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Sample records for irradiated p-type magnetic

  1. Magnetic circular dichroism study of electron-irradiation induced defects in InP

    International Nuclear Information System (INIS)

    Gislason, H.P.

    1989-01-01

    A strong magnetic circular dichroism (MCD) absorption band centered at 1.07 eV in electron irradiated InP is reported. Temperature and magnetic field dependence of the signal reveal that the centre giving rise to this band is a spin triplet. By simulating neutral and reverse bias conditions of junction measurements through a careful choice of irradiation dose and starting material, the MCD band is shown to have an annealing behaviour closely resembling that of the majority carrier traps which control the Fermi level position in n- and p-type InP. The 1.07 eV MCD band represents the first magneto-optical signal connected with this family of complex irradiation-induced defects in InP. (author) 19 refs., 5 figs., 1 tab

  2. Effect of neutron irradiation on p-type silicon

    International Nuclear Information System (INIS)

    Sopko, B.

    1973-01-01

    The possibilities are discussed of silicon isotope reactions with neutrons of all energies. In the reactions, 30 Si is converted to a stable phosphorus isotope forming n-type impurities in silicon. The above reactions proceed as a result of thermal neutron irradiation. An experiment is reported involving irradiation of two p-type silicon single crystals having a specific resistance of 2000 ohm.cm and 5000 to 20 000 ohm.cm, respectively, which changed as a result of irradiation into n-type silicon with a given specific resistance. The specific resistance may be pre-calculated from the concentration of impurities and the time of irradiation. The effects of irradiation on other silicon parameters and thus on the suitability of silicon for the manufacture of semiconductor elements are discussed. (J.K.)

  3. CCE measurements and annealing studies on proton-irradiated p-type MCz silicon diodes

    CERN Document Server

    Hoedlmoser, H; Köhler, M; Nordlund, H

    2007-01-01

    Magnetic Czochralski (MCz) silicon has recently been investigated for the development of radiation tolerant detectors for future high-luminosity HEP experiments. A study of p-type MCz Silicon diodes irradiated with protons up to a fluence of has been performed by means of Charge Collection Efficiency (CCE) measurements as well as standard CV/IV characterizations. The changes of CCE, full depletion voltage and leakage current as a function of fluence are reported. A subsequent annealing study of the irradiated detectors shows an increase in effective doping concentration and a decrease in the leakage current, whereas the CCE remains basically unchanged. Two different series of detectors have been compared differing in the implantation dose of p-spray isolation as well as effective doping concentration (Neff) of the p-type bulk presumably due to a difference in thermal donor (TD) activation during processing. The series with the higher concentration of TDs shows a delayed reverse annealing of Neff after irradia...

  4. Charge collection measurements with p-type Magnetic Czochralski silicon single pad detectors

    International Nuclear Information System (INIS)

    Tosi, C.; Bruzzi, M.; Macchiolo, A.; Scaringella, M.; Petterson, M.K.; Sadrozinski, H.F.-W.; Betancourt, C.; Manna, N.; Creanza, D.; Boscardin, M.; Piemonte, C.; Zorzi, N.; Borrello, L.; Messineo, A.

    2007-01-01

    The charge collected from beta source particles in single pad detectors produced on p-type Magnetic Czochralski (MCz) silicon wafers has been measured before and after irradiation with 26 MeV protons. After a 1 MeV neutron equivalent fluence of 1x10 15 cm -2 the collected charge is reduced to 77% at bias voltages below 900 V. This result is compared with previous results from charge collection measurements

  5. TSC measurements on proton-irradiated p-type Si-sensors

    Energy Technology Data Exchange (ETDEWEB)

    Donegani, Elena; Fretwurst, Eckhart; Garutti, Erika; Junkes, Alexandra [University of Hamburg (Germany)

    2016-07-01

    Thin n{sup +}p Si sensors are potential candidates for coping with neutron equivalent fluences up to 2.10{sup 16} n{sub eq}/cm{sup 2} and an ionizing dose in the order of a few MGy, which are expected e.g. for the HL-LHC upgrade. The aim of the present work is to provide experimental data on radiation-induced defects in order to: firstly, get a deeper understanding of the properties of hadron induced defects, and secondly develop a radiation damage model based on microscopic measurements. Therefore, the outcomes of Thermally Stimulated Current measurements on 200 μm thick Float-Zone (FZ) and Magnetic Czochralski (MCz) diodes will be shown, as a results of irradiation with 23 MeV protons and isothermal annealing. The samples were irradiated in the fluence range (0.3-1).10{sup 14} n{sub eq}/cm{sup 2}, so that the maximal temperature at which the TSC signal is still sharply distinguishable from the dark current is 200 K. In particular, special focus will be given to the defect introduction rate and to the issue of boron removal in p-type silicon. Annealing studies allow to distinguish which defects mainly contribute to the leakage current and which to the space charge, and thus correlate microscopic defects properties with macroscopic sensor properties.

  6. Influence of {gamma} and neutron irradiation on the magnetic properties of Nd Fe B, Alnico, and Mn Al type permanent magnets

    Energy Technology Data Exchange (ETDEWEB)

    Jipa, S; Setnescu, R; Kappel, W; Alexandru, St [Institute of Research and Design for Electrical Engineering, ICPE - Electrostatica, Splaiul Unirii 313, Sect. 3, R-74204 Bucharest (Romania)

    1996-12-31

    The influence of {gamma} and neutron irradiation on the magnetic properties of Nd Fe B, Alnico and Mn Al type permanent magnets was studied. With the used neutron energies and fluences, no changes in remanent induction values for Nd Fe B type permanent magnets are shown. For Alnico type permanent magnets the remanent induction changes are due to reversible variation of the magnetization directions. Only in case of Mn Al type permanent magnets irreversible structural changes take place, which lead to irreversible losses of induction. (author) 4 figs., 2 tabs., 12 refs. (author).

  7. Influence of γ and neutron irradiation on the magnetic properties of Nd Fe B, Alnico, and Mn Al type permanent magnets

    International Nuclear Information System (INIS)

    Jipa, S.; Setnescu, R.; Kappel, W.; Alexandru, St.

    1995-01-01

    The influence of γ and neutron irradiation on the magnetic properties of Nd Fe B, Alnico and Mn Al type permanent magnets was studied. With the used neutron energies and fluences, no changes in remanent induction values for Nd Fe B type permanent magnets are shown. For Alnico type permanent magnets the remanent induction changes are due to reversible variation of the magnetization directions. Only in case of Mn Al type permanent magnets irreversible structural changes take place, which lead to irreversible losses of induction. (author) 4 figs., 2 tabs., 12 refs. (author)

  8. Hardness of AISI type 410 martensitic steels after high temperature irradiation via nanoindentation

    Science.gov (United States)

    Waseem, Owais Ahmed; Jeong, Jong-Ryul; Park, Byong-Guk; Maeng, Cheol-Soo; Lee, Myoung-Goo; Ryu, Ho Jin

    2017-11-01

    The hardness of irradiated AISI type 410 martensitic steel, which is utilized in structural and magnetic components of nuclear power plants, is investigated in this study. Proton irradiation of AISI type 410 martensitic steel samples was carried out by exposing the samples to 3 MeV protons up to a 1.0 × 1017 p/cm2 fluence level at a representative nuclear reactor coolant temperature of 350 °C. The assessment of deleterious effects of irradiation on the micro-structure and mechanical behavior of the AISI type 410 martensitic steel samples via transmission electron microscopy-energy dispersive spectroscopy and cross-sectional nano-indentation showed no significant variation in the microscopic or mechanical characteristics. These results ensure the integrity of the structural and magnetic components of nuclear reactors made of AISI type 410 martensitic steel under high-temperature irradiation damage levels up to approximately 5.2 × 10-3 dpa.

  9. Irradiation and annealing of p-type silicon carbide

    Energy Technology Data Exchange (ETDEWEB)

    Lebedev, Alexander A.; Bogdanova, Elena V.; Grigor' eva, Maria V.; Lebedev, Sergey P. [A.F. Ioffe Physical-Technical Institute, St. Petersburg, 194021 (Russian Federation); Kozlovski, Vitaly V. [St. Petersburg State Polytechnic University, St. Petersburg, 195251 (Russian Federation)

    2014-02-21

    The development of the technology of semiconductor devices based on silicon carbide and the beginning of their industrial manufacture have made increasingly topical studies of the radiation hardness of this material on the one hand and of the proton irradiation to form high-receptivity regions on the other hand. This paper reports on a study of the carrier removal rate (V{sub d}) in p-6H-SiC under irradiation with 8 MeV protons and of the conductivity restoration in radiation- compensated epitaxial layers of various p-type silicon carbide polytypes. V{sub d} was determined by analysis of capacitance-voltage characteristics and from results of Hall effect measurements. It was found that the complete compensation of samples with the initial value of Na - Nd ≈ 1.5 × 10{sup 18} cm{sup −3} occurs at an irradiation dose of ∼1.1 × 10{sup 16} cm{sup −2}. It is shown that specific features of the sublimation layer SiC (compared to CVD layers) are clearly manifested upon the gamma and electron irradiation and are hardly noticeable under the proton and neutron irradiation. It was also found that the radiation-induced compensation of SiC is retained after its annealing at ≤1000°C. The conductivity is almost completely restored at T ≥ 1200°C. This character of annealing of the radiation compensation is independent of a silicon carbide polytype and the starting doping level of the epitaxial layer. The complete annealing temperatures considerably exceed the working temperatures of SiC-based devices. It is shown that the radiation compensation is a promising method in the technology of high-temperature devices based on SiC.

  10. Characterization of proton and neutron irradiated low resistivity p-on-n magnetic Czochralski ministrip sensors and diodes

    International Nuclear Information System (INIS)

    Pacifico, Nicola; Dolenc Kittelmann, Irena; Fahrer, Manuel; Moll, Michael; Militaru, Otilia

    2011-01-01

    Transient Current Technique (TCT) and Charge Collection Efficiency (CCE) measurements were performed on low resistivity (280Ωcm) n-bulk, p-readout magnetic Czochralski ministrip sensors and diodes. The detectors were irradiated with neutrons and 24 GeV/c protons up to a total NIEL equivalent fluence of 8×10 15 /cm 2 . The study was addressed to assess the radiation tolerance of the detectors up to fluences expected in the next generations of High Energy Physics experiments. The charge collection efficiency after irradiation was found to be much higher than for standard FZ silicon p-in-n sensors. The underlying physics of this remarkable result was investigated by performing Edge-TCT measurements on one of the neutron irradiated ministrip sensors to extract detailed informations about the field and efficiency profiles of the detector.

  11. Characterization of proton and neutron irradiated low resistivity p-on-n magnetic Czochralski ministrip sensors and diodes

    Energy Technology Data Exchange (ETDEWEB)

    Pacifico, Nicola, E-mail: nicola.pacifico@cern.ch [CERN, Geneva (Switzerland); Dolenc Kittelmann, Irena; Fahrer, Manuel; Moll, Michael [CERN, Geneva (Switzerland); Militaru, Otilia [UCL, Louvain (Belgium)

    2011-12-01

    Transient Current Technique (TCT) and Charge Collection Efficiency (CCE) measurements were performed on low resistivity (280{Omega}cm) n-bulk, p-readout magnetic Czochralski ministrip sensors and diodes. The detectors were irradiated with neutrons and 24 GeV/c protons up to a total NIEL equivalent fluence of 8 Multiplication-Sign 10{sup 15}/cm{sup 2}. The study was addressed to assess the radiation tolerance of the detectors up to fluences expected in the next generations of High Energy Physics experiments. The charge collection efficiency after irradiation was found to be much higher than for standard FZ silicon p-in-n sensors. The underlying physics of this remarkable result was investigated by performing Edge-TCT measurements on one of the neutron irradiated ministrip sensors to extract detailed informations about the field and efficiency profiles of the detector.

  12. Magnetic properties of point defects in proton irradiated diamond

    Energy Technology Data Exchange (ETDEWEB)

    Makgato, T.N., E-mail: Thuto.Makgato@students.wits.ac.za [School of Physics, University of the Witwatersrand, Johannesburg 2050 (South Africa); Sideras-Haddad, E. [School of Physics, University of the Witwatersrand, Johannesburg 2050 (South Africa); Center of Excellence in Strong Materials, Physics Building, University of the Witwatersrand, Johannesburg 2050 (South Africa); Ramos, M.A. [CMAM, Centro de Micro-Analisis de Materiales, Universidad Autónoma de Madrid, C/Faraday 3, Campus de Cantoblanco, E-28049 Madrid (Spain); Departamento de Fisica de la Materia Condensada, Condensed Matter Physics Center (IFIMAC) and Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, 28049 Madrid (Spain); García-Hernández, M. [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, E-28049 Madrid (Spain); Climent-Font, A.; Zucchiatti, A.; Muñoz-Martin, A. [CMAM, Centro de Micro-Analisis de Materiales, Universidad Autónoma de Madrid, C/Faraday 3, Campus de Cantoblanco, E-28049 Madrid (Spain); Shrivastava, S. [School of Physics, University of the Witwatersrand, Johannesburg 2050 (South Africa); Erasmus, R. [School of Physics, University of the Witwatersrand, Johannesburg 2050 (South Africa); Center of Excellence in Strong Materials, Physics Building, University of the Witwatersrand, Johannesburg 2050 (South Africa)

    2016-09-01

    We investigate the magnetic properties of ultra-pure type-IIa diamond following irradiation with proton beams of ≈1–2 MeV energy. SQUID magnetometry indicate the formation of Curie type paramagnetism according to the Curie law. Raman and Photoluminescence spectroscopy measurements show that the primary structural features created by proton irradiation are the centers: GR1, ND1, TR12 and 3H. The Stopping and Range of Ions in Matter (SRIM) Monte Carlo simulations together with SQUID observations show a strong correlation between vacancy production, proton fluence and the paramagnetic factor. At an average surface vacancy spacing of ≈1–1.6 nm and bulk (peak) vacancy spacing of ≈0.3-0.5 nm Curie paramagnetism is induced by formation of ND1 centres with an effective magnetic moment μ{sub eff}~(0.1–0.2)μ{sub B}. No evidence of long range magnetic ordering is observed in the temperature range 4.2-300 K. - Highlights: • Proton macro-irradiation of pure diamond creates fluence dependent paramagnetism. • The effective magnetic moment is found to be in the range μ{sub eff}~(0.1–0.2)μ{sub B}. • No evidence of long range magnetic ordering is observed.

  13. Magnetic properties of point defects in proton irradiated diamond

    International Nuclear Information System (INIS)

    Makgato, T.N.; Sideras-Haddad, E.; Ramos, M.A.; García-Hernández, M.; Climent-Font, A.; Zucchiatti, A.; Muñoz-Martin, A.; Shrivastava, S.; Erasmus, R.

    2016-01-01

    We investigate the magnetic properties of ultra-pure type-IIa diamond following irradiation with proton beams of ≈1–2 MeV energy. SQUID magnetometry indicate the formation of Curie type paramagnetism according to the Curie law. Raman and Photoluminescence spectroscopy measurements show that the primary structural features created by proton irradiation are the centers: GR1, ND1, TR12 and 3H. The Stopping and Range of Ions in Matter (SRIM) Monte Carlo simulations together with SQUID observations show a strong correlation between vacancy production, proton fluence and the paramagnetic factor. At an average surface vacancy spacing of ≈1–1.6 nm and bulk (peak) vacancy spacing of ≈0.3-0.5 nm Curie paramagnetism is induced by formation of ND1 centres with an effective magnetic moment μ eff ~(0.1–0.2)μ B . No evidence of long range magnetic ordering is observed in the temperature range 4.2-300 K. - Highlights: • Proton macro-irradiation of pure diamond creates fluence dependent paramagnetism. • The effective magnetic moment is found to be in the range μ eff ~(0.1–0.2)μ B . • No evidence of long range magnetic ordering is observed.

  14. Variation of minority charge carrier lifetime in high-resistance p-type silicon under irradiation

    International Nuclear Information System (INIS)

    Basheleishvili, Z.V.; Garnyk, V.S.; Gorin, S.N.; Pagava, T.A.

    1984-01-01

    The minority carrier lifetime (tau) variation was studied in the process of p-type silicon bombardment with fast 8 MeV electrons. The irradiation and all measurements were carried out at room temperature. The tau quantity was measured by the photoconductivity attenuation method at a low injection level 20% measurement error; the resistivity was measured by the four-probe method (10% error). The resistivity and minority charge carrier lifetime tau are shown to increase with the exposure dose. It is supposed that as radiation dose increases, the rearrangement of the centres responsible for reducing the lifetime occurs and results in a tau increase in the material being irradiated, however the tau value observed in the original samples is not attained. The restoration of the minority carrier lifetime in p-type high-resistance silicon with a growing exposure dose might proceed due to reduction in the free carrier concentration

  15. Surface modifications caused by a swift heavy ion irradiation on crystalline p-type gallium antimonide

    Science.gov (United States)

    Jadhav, Vidya

    2015-09-01

    Surface modifications caused by a swift heavy ion irradiation on crystalline p-type gallium antimonide crystal have been reported. Single crystal, 1 0 0> orientations and ∼500 μm thick p-type GaSb samples with carrier concentration of 3.30 × 1017 cm-3 were irradiated at 100 MeV Fe7+ ions. We have used 15UD Pelletron facilities at IUAC with varying fluences of 5 × 1010-1 × 1014 ions cm-2. The effects of irradiation on these samples have been investigated using, spectroscopic ellipsometry, atomic force microscopy and ultraviolet-visible-NIR spectroscopy techniques. Ellipsometry parameters, psi (Ψ) and delta (Δ) for the unirradiated sample and samples irradiated with different fluences were recorded. The data were fit to a three phase model to determine the refractive index and extinction coefficient. The refractive index and extinction coefficient for various fluences in ultraviolet, visible, and infrared, regimes were evaluated. Atomic force microscopy has been used to study these surface modifications. In order to have more statistical information about the surface, we have plotted the height structure histogram for all the samples. For unirradiated sample, we observed the Gaussian fitting. This result indicates the more ordered height structure symmetry. Whereas for the sample irradiated with the fluence of 1 × 1013, 5 × 1013 and 1 × 1014 ions cm-2, we observed the scattered data. The width of the histogram for samples irradiated up to the fluence of 1 × 1013 ion cm-2 was found to be almost same however it decreased at higher fluence. UV reflectance spectra of the sample irradiated with increasing fluences exhibit three peaks at 292, 500 and 617 nm represent the high energy GaSb; E1, E1 + Δ and E2 band gaps in all irradiated samples.

  16. Enhancements of the critical currents of YBaCuO single crystals by neutron (n) and proton (p) irradiation

    International Nuclear Information System (INIS)

    Vlcek, B.M.; Frischherz, M.C.; Vishwanathan, H.K.; Welp, U.; Crabtree, G.W.; Kirk, M.A.

    1992-01-01

    We present results of magnetization hysteresis and T c measurements of neutron and proton irradiated YBaCuO single crystals. The crystals used for comparison were irradiated to a fluence of 2x10 7 n/cm 2 (n,E > 0.1MeV) and 1x10 16 p/cm 2 (p,E=3.5MeV). The critical currents at 1T and 10K are enhanced by a factor of 5 for the neutron irradiated and a factor of 9 for the proton irradiated sample respectively. After irradiation the crystals were annealed at 100, 200 and 300C for 8h each in air. Following each annealing step the critical temperature and the magnetization hysteresis at 10 and 70K was measured. Upon annealing, we observe a decrease of the critical currents, which is more pronounced for the proton irradiated sample. This decrease is related to the removal of point defects or their small clusters. Thus, their contribution to pinning can be studied. The critical temperature decreases after both types of irradiation by about 0.5K and is fully recovered after annealing

  17. Tailoring magnetism by light-ion irradiation

    International Nuclear Information System (INIS)

    Fassbender, J; Ravelosona, D; Samson, Y

    2004-01-01

    Owing to their reduced dimensions, the magnetic properties of ultrathin magnetic films and multilayers, e.g. magnetic anisotropies and exchange coupling, often depend strongly on the surface and interface structure. In addition, chemical composition, crystallinity, grain sizes and their distribution govern the magnetic behaviour. All these structural properties can be modified by light-ion irradiation in an energy range of 5-150 keV due to the energy loss of the ions in the solid along their trajectory. Consequently the magnetic properties can be tailored by ion irradiation. Similar effects can also be observed using Ga + ion irradiation, which is the common ion source in focused ion beam lithography. Examples of ion-induced modifications of magnetic anisotropies and exchange coupling are presented. This review is limited to radiation-induced structural changes giving rise to a modification of magnetic parameters. Ion implantation is discussed only in special cases. Due to the local nature of the interaction, magnetic patterning without affecting the surface topography becomes feasible, which may be of interest in applications. The main patterning technique is homogeneous ion irradiation through masks. Focused ion beam and ion projection lithography are usually only relevant for larger ion masses. The creation of magnetic feature sizes below 50 nm is shown. In contrast to topographic nanostructures the surrounding area of these nanostructures can be left ferromagnetic, leading to new phenomena at their mutual interface. Most of the material systems discussed here are important for technological applications. The main areas are magnetic data storage applications, such as hard magnetic media with a large perpendicular magnetic anisotropy or patterned media with an improved signal to noise ratio and magnetic sensor elements. It will be shown that light-ion irradiation has many advantages in the design of new material properties and in the fabrication technology of

  18. Different early effect of irradiation in brain and small cell lung cancer examined by in vivo 31P-magnetic resonance spectroscopy

    DEFF Research Database (Denmark)

    Kristjansen, P E; Pedersen, A G; Quistorff, B

    1992-01-01

    Early effects of irradiation were evaluated by non-invasive in vivo 31P-magnetic resonance spectroscopy (31P-MRS) of two small cell lung cancer (SCLC) tumor lines CPH SCCL 54A and 54B, in nude mice. The tumors were originally derived from the same patient and have similar morphology and growth...

  19. Some physical properties of irradiated and non-irradiated oxide glasses containing uranium

    International Nuclear Information System (INIS)

    Simon, V.; Ardelean, I.; Simon, S.; Cozar, O.; Milea, I.; Lupsa, I.; Mih, V.

    1995-01-01

    The x U O 3 (1-x) [2 P 2 O 5 · Na 2 O] non-irradiated and gamma irradiated glasses (0 3+ , U 4+ and U 5+ ions. The gamma irradiation induces paramagnetic defects around the glass network forming sites occupied by phosphorous atoms. The non-irradiated samples are weak paramagnetic up to x = 0.1. For higher U O 3 concentration (0.1 < x ≤ 0.2) the magnetic measurements indicated a larger number of paramagnetic ions which are magnetically isolated and exhibit a Curie type behaviour. (author) 5 figs., 14 refs

  20. Surface modifications caused by a swift heavy ion irradiation on crystalline p-type gallium antimonide

    Energy Technology Data Exchange (ETDEWEB)

    Jadhav, Vidya, E-mail: vj1510@yahoo.com

    2015-09-01

    Surface modifications caused by a swift heavy ion irradiation on crystalline p-type gallium antimonide crystal have been reported. Single crystal, 1 0 0〉 orientations and ∼500 μm thick p-type GaSb samples with carrier concentration of 3.30 × 10{sup 17} cm{sup −3} were irradiated at 100 MeV Fe{sup 7+} ions. We have used 15UD Pelletron facilities at IUAC with varying fluences of 5 × 10{sup 10}–1 × 10{sup 14} ions cm{sup −2}. The effects of irradiation on these samples have been investigated using, spectroscopic ellipsometry, atomic force microscopy and ultraviolet–visible–NIR spectroscopy techniques. Ellipsometry parameters, psi (Ψ) and delta (Δ) for the unirradiated sample and samples irradiated with different fluences were recorded. The data were fit to a three phase model to determine the refractive index and extinction coefficient. The refractive index and extinction coefficient for various fluences in ultraviolet, visible, and infrared, regimes were evaluated. Atomic force microscopy has been used to study these surface modifications. In order to have more statistical information about the surface, we have plotted the height structure histogram for all the samples. For unirradiated sample, we observed the Gaussian fitting. This result indicates the more ordered height structure symmetry. Whereas for the sample irradiated with the fluence of 1 × 10{sup 13}, 5 × 10{sup 13} and 1 × 10{sup 14} ions cm{sup −2}, we observed the scattered data. The width of the histogram for samples irradiated up to the fluence of 1 × 10{sup 13} ion cm{sup −2} was found to be almost same however it decreased at higher fluence. UV reflectance spectra of the sample irradiated with increasing fluences exhibit three peaks at 292, 500 and 617 nm represent the high energy GaSb; E{sub 1}, E{sub 1} + Δ and E{sub 2} band gaps in all irradiated samples.

  1. Surface modifications caused by a swift heavy ion irradiation on crystalline p-type gallium antimonide

    International Nuclear Information System (INIS)

    Jadhav, Vidya

    2015-01-01

    Surface modifications caused by a swift heavy ion irradiation on crystalline p-type gallium antimonide crystal have been reported. Single crystal, 1 0 0〉 orientations and ∼500 μm thick p-type GaSb samples with carrier concentration of 3.30 × 10 17 cm −3 were irradiated at 100 MeV Fe 7+ ions. We have used 15UD Pelletron facilities at IUAC with varying fluences of 5 × 10 10 –1 × 10 14 ions cm −2 . The effects of irradiation on these samples have been investigated using, spectroscopic ellipsometry, atomic force microscopy and ultraviolet–visible–NIR spectroscopy techniques. Ellipsometry parameters, psi (Ψ) and delta (Δ) for the unirradiated sample and samples irradiated with different fluences were recorded. The data were fit to a three phase model to determine the refractive index and extinction coefficient. The refractive index and extinction coefficient for various fluences in ultraviolet, visible, and infrared, regimes were evaluated. Atomic force microscopy has been used to study these surface modifications. In order to have more statistical information about the surface, we have plotted the height structure histogram for all the samples. For unirradiated sample, we observed the Gaussian fitting. This result indicates the more ordered height structure symmetry. Whereas for the sample irradiated with the fluence of 1 × 10 13 , 5 × 10 13 and 1 × 10 14 ions cm −2 , we observed the scattered data. The width of the histogram for samples irradiated up to the fluence of 1 × 10 13 ion cm −2 was found to be almost same however it decreased at higher fluence. UV reflectance spectra of the sample irradiated with increasing fluences exhibit three peaks at 292, 500 and 617 nm represent the high energy GaSb; E 1 , E 1 + Δ and E 2 band gaps in all irradiated samples

  2. Magnetism in the p-type Monolayer II-VI semiconductors SrS and SrSe

    Science.gov (United States)

    Lin, Heng-Fu; Lau, Woon-Ming; Zhao, Jijun

    2017-01-01

    Using density functional theory calculations, we study the electronic and magnetic properties of the p-type monolayer II-VI semiconductors SrX (X = S,Se). The pristine SrS and SrSe monolayers are large band gap semiconductor with a very flat band in the top valence band. Upon injecting hole uniformly, ferromagnetism emerges in those system in a large range of hole density. By varying hole density, the systems also show complicated phases transition among nonmagnetic semiconductor, half metal, magnetic semiconductor, and nonmagnetic metal. Furthermore, after introducing p-type dopants in SrS and SrSe via substitutionary inserting P (or As) dopants at the S (or Se) sites, local magnetic moments are formed around the substitutional sites. The local magnetic moments are stable with the ferromagnetic order with appreciable Curie temperature. The ferromagnetism originates from the instability of the electronic states in SrS and SrSe with the large density of states at the valence band edge, which demonstrates a useful strategy for realizing the ferromagnetism in the two dimensional semiconductors. PMID:28378761

  3. Switching the uniaxial magnetic anisotropy by ion irradiation induced compensation

    Science.gov (United States)

    Yuan, Ye; Amarouche, Teyri; Xu, Chi; Rushforth, Andrew; Böttger, Roman; Edmonds, Kevin; Campion, Richard; Gallagher, Bryan; Helm, Manfred; Jürgen von Bardeleben, Hans; Zhou, Shengqiang

    2018-04-01

    In the present work, the uniaxial magnetic anisotropy of GaMnAsP is modified by helium ion irradiation. According to the micro-magnetic parameters, e.g. resonance fields and anisotropy constants deduced from ferromagnetic resonance measurements, a rotation of the magnetic easy axis from out-of-plane [0 0 1] to in-plane [1 0 0] direction is achieved. From the application point of view, our work presents a novel avenue in modifying the uniaxial magnetic anisotropy in GaMnAsP with the possibility of lateral patterning by using lithography or focused ion beam.

  4. Study on 150μm thick n- and p-type epitaxial silicon sensors irradiated with 24 GeV/c protons and 1 MeV neutrons

    International Nuclear Information System (INIS)

    Kaska, Katharina; Moll, Michael; Fahrer, Manuel

    2010-01-01

    A study on 150μm epitaxial (EPI) n- and p-type silicon diodes irradiated with neutrons up to 8x10 15 n/cm 2 and protons up to 1.7x10 15 p/cm 2 has been performed by means of CV/IV, charge collection efficiency (CCE) and transient current technique (TCT) measurements. It is found that the effective space charge density increases three times faster after proton than after neutron irradiation with a slightly higher effective space charge generation rate for n-type material compared to p-type material. A drop in charge collection efficiency already at fluences of 1x10 12 n eq /cm 2 can be seen in n-type material, but is absent in p-type material. TCT measurements show space charge sign inversion from positive to negative charge in n-type material after neutron irradiation and from negative to positive space charge in p-type material after proton irradiation. No difference was found in the response of diodes manufactured by different producers out of the same wafer material.

  5. Effects of proton irradiation on electronic structure of NdFeB permanent magnets

    Energy Technology Data Exchange (ETDEWEB)

    Yang, L. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Zhen, L. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)], E-mail: lzhen@hit.edu.cn; Xu, C.Y.; Sun, X.Y.; Shao, W.Z. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2009-09-15

    Effects of proton irradiation on electronic structure and atomic local structure of N35EH-type NdFeB permanent magnet were investigated by soft X-ray absorption spectrometry and Moessbauer spectrometry. The local coordination environment of Fe atoms changes after proton irradiation, and the average hyperfine field H{sub in} of the magnets decreases from 288.4 to 286.9 kOe. The effects of irradiation on Fe atoms local environment at different lattice sites are different. The near edge structure of Fe L{sub 3} edge is changed, indicating the density of unoccupied state of Fe 3d electrons increases after proton irradiation.

  6. Defect formation in n-type InP at elevated temperatures of irradiation

    International Nuclear Information System (INIS)

    Kozlovskij, V.V.; Kol'chenko, T.I.; Lomako, V.M.; Moroz, S.E.

    1990-01-01

    Effect of irradiation temperature within 25-250 deg C traps in InP. Rate of most deep level introduction, as well as, rate of charge carrier removing at the increase of irradiation temperature are shown to decrease and it is explained by defect annealing occuring simultaneously with irradiation

  7. Investigation of the stability of polysilicon layers in SOI-structures under irradiation by electrons and hard magnetic field influence

    Directory of Open Access Journals (Sweden)

    Khoverko Yu. N.

    2010-10-01

    Full Text Available The properties of recrystallized polysilicon on insulator layers of p-type conductive SOI-structures with different carrier concentration irradiated with high-energy electrons flow about 1017 сm–2 in temperature range 4,2—300 К and high magnetic fields were investigated. It was found that heavily doped laser recrystallized polysilicon on insulator layers show its radiation resistance under irradiation with high-energy electrons and magnetoresistance of such material remains quite low in magnetic field about 14 T does not exceed 1—2%. Such qulity can be applied in designing of microelectronic sensors of mechanical values operable in hard conditions of exploitation.

  8. Magnetic properties of the filled skutterudite-type structure compounds GdRu4P12 and TbRu4P12 synthesized under high pressure

    OpenAIRE

    Sekine, C; Uchiumi, T; Shirotani, I; Matsuhira, kazuyuki; Sakakibara, T; Goto, T; Yagi, T

    2000-01-01

    We have succeeded in synthesizing filled skutterudite-type structure compounds GdRu4P12 and TbRu4P12 under high pressure. The magnetic properties of GdRu4P12 and TbRu4P12 have been studied by means of electrical resistivity, magnetic susceptibility, and magnetization measurements. Magnetic experiments suggest that the Gd and Tb ions in the compounds have trivalent state. The compound GdRu4P12 displays features that suggest the occurrence of antiferromagnetic ordering below TN=22 K. In TbRu4P1...

  9. Antisite defects in γ-irradiated InP and InP crystals

    International Nuclear Information System (INIS)

    Aliev, M.I.; Rashidova, Sh.Sh.; Gusejnova, M.A.; Gadzhieva, N.N.

    2008-01-01

    By means of TL and IR spectroscopy methods, it has been found that γ-irradiation of lnP single crystals doped with Sn leads to TL peak appearance at 230 K with activation energy E a =0.19 eV. This peak is connected with vacancy-antisite donor-type doped defect complex formation under irradiation [ru

  10. Performance of p-type micro-strip detectors after irradiation to $7.5x10^{15} p/cm^{2}$

    CERN Document Server

    Allport, Philip P; Lozano-Fantoba, Manuel; Sutcliffe, Peter; Velthuis, J J; Vossebeld, Joost Herman

    2004-01-01

    Exploiting the advantages of reading out segmented silicon from the n-side, we have produced test detectors with LHC pitch but 1 cm long strips which even after proton irradiation at the CERN PS to 7.5*10 /sup 15/ cm/sup -2/ show signal to noise greater than 8:1 using LHC speed electronics. This dose exceeds by a factor of 2 that required for a replacement of the ATLAS semiconductor tracker to cope with an upgrade of the LHC to a Super-LHC with 10 times greater luminosity. These detectors were processed on p-type starting material of resistivity ~ 2 k Omega cm and, unlike n-in-n designs, only required single-sided processing. Such technology should therefore provide a relatively inexpensive route to replacing the central tracking at both ATLAS and CMS for Super-LHC. The shorter strip length is required to limit the noise. Even at these extreme doses 30% of the non-irradiated signal is seen. This 7000e/sup -/ signal (in 280 mu m thick sensors) is very competitive with the post irradiation performance of other,...

  11. Characteristics of accumulation of recombination centers due to irradiation of p-type Si

    International Nuclear Information System (INIS)

    Kazakevich, L.A.; Lugakov, P.F.; Filippov, I.M.

    1989-01-01

    Irradiation of Czochralski-grown p-type Si single crystals results primarily in creation of recombination-active radiation defects which give rise to a donor energy level at E v + 0.30-0.38 eV in the band gap. The ideas on the structure and mechanisms of formation of these radiation defects are continuously evolving and at present the most widely held view is that which assumes that the K centers can be carbon-oxygen-divacancy complexes or interstitial carbon-interstitial oxygen pairs. The authors investigated the recombination properties of such centers

  12. Temperature dependence of magnetoresistance in neutron-irradiated and unirradiated high resistivity p-type silicon

    International Nuclear Information System (INIS)

    Yildirim, M.; Efeoglu, H.; Abay, B.; Yogurtcu, Y.K.

    1996-01-01

    The temperature dependence of the transverse magnetoresistance in irradiated and unirradiated p-type Si is studied in the range from 120 to 290 K. The magnetoresistance coefficients for the unirradiated left angle 001 right angle and left angle 1 anti 10 right angle samples increases with decreasing sample temperature in the range from 160 to 290 K, however, this behavior is reversed below 160 K. It is proposed that this reversal is due to the double injection effect. The magnetoresistance coefficient for the irradiated left angle 001 right angle sample increases with decreasing sample temperature in the range of 120 to 290 K and is greater than that for the unirradiated left angle 001 right angle sample. This result can be explained by increased scattering due to the increased number of defects produced by irradiation. On the other hand, the magnetoresistance coefficient for the unirradiated left angle 1 anti 10 right angle sample is found to be greater than that of the unirradiated left angle 001 right angle sample. (orig.)

  13. Gamma-Ray Irradiation Effects on the Characteristics of New Material P Type 6H-SiC Ni-Schottky Diodes (Application For Nuclear Fuel Facilities)

    International Nuclear Information System (INIS)

    U-Sudjadi; T-Ohshima, N. Iwamoto; S-Hishiki; N-Iwamoto, K. Kawano

    2007-01-01

    Effects of gamma-ray irradiation on electrical characteristics of new material p type 6H-SiC Ni-Schottky diodes were investigated. Ni Schottky diodes fabricated on p type 6H-SiC epi-layer were irradiated with gamma-rays at RT. The electrical characteristics of the diodes were evaluated before and after irradiation. The value of the on-resistance does not change up to 1 MGy, and the value increases with increasing absorbed dose above 1 MGy. For n factor, no significant increase is observed below 500 kGy, however, the value increases above 500 kGy. Schottky Barrier Height (SBH) decreases with increasing absorbed dose. Leakage current tends to increase due to irradiation. (author)

  14. Magnetic patterning by means of ion irradiation and implantation

    International Nuclear Information System (INIS)

    Fassbender, J.; McCord, J.

    2008-01-01

    A pure magnetic patterning by means of ion irradiation which relies on a local modification of the magnetic anisotropy of a magnetic multilayer structure has been first demonstrated in 1998. Since then also other magnetic properties like the interlayer exchange coupling, the exchange bias effect, the magnetic damping behavior and the saturation magnetization to name a few have also been demonstrated to be affected by ion irradiation or ion implantation. Consequently, all these effects can be used if combined with a masking technique or employing direct focused ion beam writing for a magnetic patterning and thus an imprinting of an artificial magnetic domain structure, which subsequently modifies the integral magnetization reversal behavior or the magnetization dynamics of the film investigated. The present review will summarize how ion irradiation and implantation can affect the magnetic properties by means of structural modifications. The main part will cover the present status with respect to the pure magnetic patterning of micro- and nano structures

  15. P-type conduction in Mg-doped GaN treated with low-energy electron beam irradiation (LEEBI)

    International Nuclear Information System (INIS)

    Amano, Hiroshi; Kito, Masahiro; Hiramatsu, Kazumasa

    1989-01-01

    Distinct p-type conduction is realized with Mg-doped GaN by the low-energy electron-beam irradiation (LEEBI) treatment, and the properties of the GaN p-n junction LED are reported for the first time. It was found that the LEEBI treatment drastically lowers the resistivity and remarkably enhances the PL efficiency of MOVPE-grown Mg-doped GaN. The Hall effect measurement of this Mg-doped GaN treated with LEEBI at room temperature showed that the hole concentration is ∼2·10 16 cm -3 , the hole mobility is ∼8 cm 2 /V·s and the resistivity is ∼35Ω· cm. The p-n junction LED using Mg-doped GaN treated with LEEBI as the p-type material showed strong near-band-edge emission due to the hole injection from the p-layer to the n-layer at room temperature. (author)

  16. Effect of {gamma}-ray irradiation on the magnetic properties of NdFeB and Fe-Cr-Co permanent magnets

    Energy Technology Data Exchange (ETDEWEB)

    Gao, R.S. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Zhen, L. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)]. E-mail: zhenl@hit.edu.cn; Li, G.A. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Xu, C.Y. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Shao, W.Z. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2006-07-15

    The effect of {gamma}-ray irradiation on the magnetic properties of NdFeB and Fe-Cr-Co permanent magnets has been investigated. The magnetic flux loss of two kinds of magnets before and after irradiation was measured. Results show that the effect of {gamma}-ray irradiation on the magnetic properties of sintered NdFeB is not so obvious as that on Fe-Cr-Co magnet. Irradiation-induced damage from {gamma}-ray for the Fe-Cr-Co magnets was characterized for the first time. The decline of permanent magnetic properties of Fe-Cr-Co magnet induced by {gamma}-ray irradiation is reversible except for the maximum energy product (BH){sub max}. The difference of coercivity mechanism between these two kinds of permanent magnets is responsible for the different dependence of magnetic properties loss induced by {gamma}-ray irradiation.

  17. Processing and first characterization of detectors made with high resistivity n- and p-type Czochralski silicon

    International Nuclear Information System (INIS)

    Bruzzi, M.; Bisello, D.; Borrello, L.; Borchi, E.; Boscardin, M.; Candelori, A.; Creanza, D.; Dalla Betta, G.-F.; DePalma, M.; Dittongo, S.; Focardi, E.; Khomenkov, V.; Litovchenko, A.; Macchiolo, A.; Manna, N.; Menichelli, D.; Messineo, A.; Miglio, S.; Petasecca, M.; Piemonte, C.; Pignatel, G.U.; Radicci, V.; Ronchin, S.; Scaringella, M.; Segneri, G.; Sentenac, D.; Tosi, C.; Zorzi, N.

    2005-01-01

    We report on the design, manufacturing and first characterisation of pad diodes, test structures and microstrip detectors processed with high resistivity magnetic Czochralski (MCz) p- and n-type Si. The pre-irradiation study on newly processed microstrip detectors and test structures show a good overall quality of the processed wafers. After irradiation with 24 GeV/c protons up to 4x10 14 cm -2 the characterisation of n-on-p and p-on-n MCz Si sensors with the C-V method show a decrease of the full depletion voltage and no space charge sign inversion. Microscopic characterisation has been performed to study the role of thermal donors in Czochralski Si. No evidence of thermal donor activation was observed in n-type MCz Si detectors if contact sintering was performed at a temperature lower than 380 deg. C and the final passivation oxide was omitted

  18. Irradiation capsule for testing magnetic fusion reactor first-wall materials at 60 and 2000C

    International Nuclear Information System (INIS)

    Conlin, J.A.

    1985-08-01

    A new type of irradiation capsule has been designed, and a prototype has been tested in the Oak Ridge Research Reactor (ORR) for low-temperature irradiation of Magnetic Fusion Reactor first-wall materials. The capsule meets the requirements of the joint US/Japanese collaborative fusion reactor materials irradiation program for the irradiation of first-wall fusion reactor materials at 60 and 200 0 C. The design description and results of the prototype capsule performance are presented

  19. Meso-scale magnetic signatures for nuclear reactor steel irradiation embrittlement monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Suter, J. D., E-mail: pradeep.ramuhalli@pnnl.gov; Ramuhalli, P., E-mail: pradeep.ramuhalli@pnnl.gov; Hu, S.; Li, Y.; Jiang, W.; Edwards, D. J.; Schemer-Kohrn, A. L.; Johnson, B. R. [Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA 99352 (United States); McCloy, J. S., E-mail: john.mccloy@wsu.edu; Xu, K., E-mail: john.mccloy@wsu.edu [Washington State University, PO Box 642920, Pullman, WA 99164 (United States)

    2015-03-31

    Verifying the structural integrity of passive components in light water and advanced reactors will be necessary to ensure safe, long-term operations of the existing U.S. nuclear fleet. This objective can be achieved through nondestructive condition monitoring techniques, which can be integrated with plant operations to quantify the “state of health” of structural materials in real-time. While nondestructive methods for monitoring many classes of degradation (such as fatigue or stress corrosion cracking) are relatively advanced, this is not the case for degradation caused by irradiation. The development of nondestructive evaluation technologies for these types of degradation will require advanced materials characterization techniques and tools that enable comprehensive understanding of nuclear reactor material microstructural and behavioral changes under extreme operating environments. Irradiation-induced degradation of reactor steels causes changes in their microstructure that impacts their micro-magnetic properties. In this paper, we describe preliminary results of integrating advanced material characterization techniques with meso-scale computational models. In the future, this will help to provide an interpretive understanding of the state of degradation in structural materials. Microstructural data are presented from monocrystalline Fe and are correlated with variable-field magnetic force microscopy and micro-magnetic measurements. Ongoing research is focused on extending the measurements and models on thin films to gain insights into the structural state of irradiated materials and the resulting impact on magnetic properties. Preliminary conclusions from these correlations are presented, and next steps described.

  20. Magnetically separable nanoferrite-anchored glutathione: Aqueous homocoupling of arylboronic acids under microwave irradiation

    Science.gov (United States)

    A highly active, stable and magnetically separable glutathione based organocatalyst provided good to excellent yields to symmetric biaryls in the homocoupling of arylboronic acids under microwave irradiation. Symmetrical biaryl motifs are present in a wide range of natural p...

  1. A permanent magnet electron beam spread system used for a low energy electron irradiation accelerator

    International Nuclear Information System (INIS)

    Huang Jiang; Xiong Yongqian; Chen Dezhi; Liu Kaifeng; Yang Jun; Li Dong; Yu Tiaoqin; Fan Mingwu; Yang Bo

    2014-01-01

    The development of irradiation processing industry brings about various types of irradiation objects and expands the irradiation requirements for better uniformity and larger areas. This paper proposes an innovative design of a permanent magnet electron beam spread system. By clarifying its operation principles, the author verifies the feasibility of its application in irradiation accelerators for industrial use with the examples of its application in electron accelerators with energy ranging from 300 keV to 1 MeV. Based on the finite element analyses of electromagnetic fields and the charged particle dynamics, the author also conducts a simulation of electron dynamics in magnetic field on a computer. The results indicate that compared with the traditional electron beam scanning system, this system boosts the advantages of a larger spread area, non-power supply, simple structure and low cost, etc., which means it is not only suitable for the irradiation of objects with the shape of tubes, strips and panels, but can also achieve a desirable irradiation performance on irregular constructed objects of large size. (authors)

  2. Studies of defects in neutron-irradiated p-type silicon by admittance measurements of n+-p diodes

    International Nuclear Information System (INIS)

    Tokuda, Y.; Usami, A.

    1978-01-01

    Defects introduced in p-type silicon by neutron irradiation were studied by measuring the admittance of n + -p diodes. It was shown that the energy levels and capture cross sections estimated from the temperature dependence of the admittance had some uncertainty due to the temperature dependence of the concentration of free carriers in the bulk and the high-frequency-junction capacitance. So, we presented the method of determination of the energy levels, capture cross sections, and concentrations of defects from the frequency dependence of the admittance. This method consists of the measurements of G/ω and C as a function of frequency. From this method, assuming that capture cross sections are independent of temperature, the energy levels of E/sub v/+0.16 and E/sub v/+0.36 eV were obtained. For these defects, the calculated values of the hole capture cross section were 2.4 x 10 -14 and 3.7 x 10 -14 cm 2 , respectively. Comparing with other published data, the energy level of E/sub v/+0.36 eV was found to be correlated with the divacancy

  3. Stored energy in fusion magnet materials irradiated at low temperatures

    International Nuclear Information System (INIS)

    Chaplin, R.L.; Kerchner, H.R.; Klabunde, C.E.; Coltman, R.R.

    1989-08-01

    During the power cycle of a fusion reactor, the radiation reaching the superconducting magnet system will produce an accumulation of immobile defects in the magnet materials. During a subsequent warm-up cycle of the magnet system, the defects will become mobile and interact to produce new defect configurations as well as some mutual defect annihilations which generate heat-the release of stored energy. This report presents a brief qualitative discussion of the mechanisms for the production and release of stored energy in irradiated materials, a theoretical analysis of the thermal response of irradiated materials, theoretical analysis of the thermal response of irradiated materials during warm-up, and a discussion of the possible impact of stored energy release on fusion magnet operation 20 refs

  4. Electrophysical properties of In P crystals, irradiated with CO-60 gamma quanta

    International Nuclear Information System (INIS)

    Aliyev, M.I.; Guseynova, M.A.; Aliyev, I.M.; Ragimov, S.S.

    2005-01-01

    Full text : n-InP monocrystals were investigated before and after gamma irradiation having a doze about 10 and also within temperature interval from 77 to 320 K. On χ(T) and σ(T) dependences it is revealed that during gamma irradiation p-type antistructural defects are generated in n-InP crystals. It gives an opportunity of receiving of not alloyed semiinsulating indium fosfide [ru

  5. Magnetic properties of a stainless steel irradiated with 6 MeV Xe ions

    Science.gov (United States)

    Xu, Chaoliang; Liu, Xiangbing; Qian, Wangjie; Li, Yuanfei

    2017-11-01

    Specimens of austenitic stainless steel were irradiated with 6 MeV Xe ions at room temperature to 2, 7, 15 and 25 dpa. The vibrating sample magnetometer (VSM), grazing incidence X-ray diffraction (GIXRD) and positron annihilation lifetime spectroscopy (PLS) were carried out to analysis the magnetic properties and microstructural variations. The magnetic hysteresis loops indicated that higher irradiation damage causes more significant magnetization phenomenon. The equivalent saturated magnetization Mes and coercive force Hc were obtained from magnetic hysteresis loops. It is indicated that the Mes increases with irradiation damage. While Hc increases first to 2 dpa and then decreases continuously with irradiation damage. The different contributions of irradiation defects and ferrite precipitates on Mes and Hc can explain these phenomena.

  6. Rapid microwave-assisted regeneration of magnetic carbon nanotubes loaded with p-nitrophenol

    International Nuclear Information System (INIS)

    Cui, Chunyue; Zheng, Qingzhu; Han, Yanhe; Xin, Yanjun

    2015-01-01

    Highlights: • Magnetic CNTs material was successfully synthesized. • Magnetic CNTs have high fast adsorption rate and adsorption capacity. • Magnetic CNTs can be easily separated from the water by external magnetic field. • Magnetic CNTs can be recycled by MW irradiation regeneration. - Abstract: A novel magnetic carbon nanotubes (CNTs) adsorbent with good sorption, magnetic separability, and microwave (MW) regeneration properties was prepared successfully using thermal decomposition. The magnetic CNTs were characterized using transmission electron microscopy, energy dispersive X-ray, nitrogen adsorption (Brunauer–Emmett–Teller surface area), and X-ray diffraction and their magnetic properties were measured using a vibrating sample magnetometer. Magnetic nanoparticles (≈10 nm diameter) were dispersed uniformly on the CNTs with a magnetic CNTs surface area of 146.7 m 2 g −1 and a saturation magnetization of 21.11 emu g −1 . When the magnetic CNTs were used in the sorption of p-nitrophenol, the equilibrium time was 20 min and the sorption isotherms fit the Freundlich isotherm well. The spent magnetic CNTs could be separated magnetically and be regenerated by MW irradiation. After six adsorption and MW regeneration cycles (at 850 W for 180 s), the adsorption capacity of the magnetic CNTs was higher than that of the virgin magnetic CNTs with a low carbon loss

  7. Processing of n{sup +}/p{sup −}/p{sup +} strip detectors with atomic layer deposition (ALD) grown Al{sub 2}O{sub 3} field insulator on magnetic Czochralski silicon (MCz-si) substrates

    Energy Technology Data Exchange (ETDEWEB)

    Härkönen, J., E-mail: jaakko.harkonen@helsinki.fi [Helsinki Institute of Physics (Finland); Tuovinen, E. [Helsinki Institute of Physics (Finland); VTT Technical Research Centre of Finland, Microsystems and Nanoelectronics (Finland); Luukka, P.; Gädda, A.; Mäenpää, T.; Tuominen, E.; Arsenovich, T. [Helsinki Institute of Physics (Finland); Junkes, A. [Institute for Experimental Physics, University of Hamburg (Germany); Wu, X. [VTT Technical Research Centre of Finland, Microsystems and Nanoelectronics (Finland); Picosun Oy, Tietotie 3, FI-02150 Espoo Finland (Finland); Li, Z. [School of Materials Science and Engineering, Xiangtan University, Xiangtan, Hunan 411105 (China)

    2016-08-21

    Detectors manufactured on p-type silicon material are known to have significant advantages in very harsh radiation environment over n-type detectors, traditionally used in High Energy Physics experiments for particle tracking. In p-type (n{sup +} segmentation on p substrate) position-sensitive strip detectors, however, the fixed oxide charge in the silicon dioxide is positive and, thus, causes electron accumulation at the Si/SiO{sub 2} interface. As a result, unless appropriate interstrip isolation is applied, the n-type strips are short-circuited. Widely adopted methods to terminate surface electron accumulation are segmented p-stop or p-spray field implantations. A different approach to overcome the near-surface electron accumulation at the interface of silicon dioxide and p-type silicon is to deposit a thin film field insulator with negative oxide charge. We have processed silicon strip detectors on p-type Magnetic Czochralski silicon (MCz-Si) substrates with aluminum oxide (Al{sub 2}O{sub 3}) thin film insulator, grown with Atomic Layer Deposition (ALD) method. The electrical characterization by current–voltage and capacitance−voltage measurement shows reliable performance of the aluminum oxide. The final proof of concept was obtained at the test beam with 200 GeV/c muons. For the non-irradiated detector the charge collection efficiency (CCE) was nearly 100% with a signal-to-noise ratio (S/N) of about 40, whereas for the 2×10{sup 15} n{sub eq}/cm{sup 2} proton irradiated detector the CCE was 35%, when the sensor was biased at 500 V. These results are comparable with the results from p-type detectors with the p-spray and p-stop interstrip isolation techniques. In addition, interestingly, when the aluminum oxide was irradiated with Co-60 gamma-rays, an accumulation of negative fixed oxide charge in the oxide was observed.

  8. Effects of High-Energy Proton-Beam Irradiation on the Magnetic Properties of ZnO Nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jun Kue; Kwon, Hyeok-Jung; Cho, Yong Sub [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    There are still many problem for the application due to its unstable magnetism state and too small magnetization values. Here we investigate magnetic properties of ZnO nanorods after high-energy proton-beam irradiation. Electron spin resonance (ESR) measurement on temperature was made to identify intrinsic or extrinsic defects as well as to observe magnetic ordering after irradiation. Understanding the effects of proton beam irradiation on magnetic behavior may help to shed light on the mechanism responsible for the magnetic ordering in this material. We have investigated proton-beam irradiation effects on the magnetic properties of ZnO nanorods. After irradiation a broad ESR line is observed, indicating emergence of ferromagnetic ordering up to room temperature. In M-H curve, stronger coercive field is observed after irradiation.

  9. Magnetic phase transitions and magnetization reversal in MnRuP

    Science.gov (United States)

    Lampen-Kelley, P.; Mandrus, D.

    The ternary phosphide MnRuP is an incommensurate antiferromagnetic metal crystallizing in the non-centrosymmetric Fe2P-type crystal structure. Below the Neel transition at 250 K, MnRuP exhibits hysteretic anomalies in resistivity and magnetic susceptibility curves as the propagation vectors of the spiral spin structure change discontinuously across T1 = 180 K and T2 = 100 K. Temperature-dependent X-ray diffraction data indicate that the first-order spin reorientation occurs in the absence of a structural transition. A strong magnetization reversal (MR) effect is observed upon cooling the system through TN in moderate dc magnetic fields. Positive magnetization is recovered on further cooling through T1 and maintained in subsequent warming curves. The field dependence and training of the MR effect in MnRuP will be discussed in terms of the underlying magnetic structures and compared to anomalous MR observed in vanadate systems. This work is supported by the Gordon and Betty Moore Foundation GBMF4416 and U.S. DOE, Office of Science, BES, Materials Science and Engineering Division.

  10. Neutron irradiation effects on magnetic properties of some Heusler alloys

    International Nuclear Information System (INIS)

    Onodera, Hideya; Shinohara, Takeshi; Yamamoto, Hisao; Watanabe, Hiroshi

    1975-01-01

    The neutron irradiation effects were studied with measurements of temperature dependence of magnetization in ordered and disordered Heusler alloys. The irradiation was carried out in JMTR with a total flux of fast neutrons of 10 20 nvt. Fully ordered Cu 2 MnIn, partially ordered Cu 2 MnAl and completely disordered Cu 2 MnSn were prepared with various temperature treatments. The magnetization-temperature curves of each specimen were measured before and after irradiation. In the irradiated Cu 2 MnIn, the disordering by the irradiation gave rise to a decrease of magnetization, and the temperature dependence of magnetization showed that the disordered region contained various regions with different degrees of disorder. For the distribution of the disordered region, the calculation based on the theory of temperature spike by Seitz and Koekler gave a feasible result that a disordered region comprised a central core with a radius of 5.4 A which was completely disordered and a periphery of 3.3 A thickness which was partially disordered. From the magnetization-temperature curves of Cu 2 MnAl, it was considered that the disordered regions induced by the irradiation had different properties from those induced by the heat treatment. The former were the localized and comprised regions corresponding to various degrees of disorder, while the latter spread spatially in a wide range with a certain degree of disorder. The ordering by enhanced diffusion occurred simultaneously to an extent comparable to the disordering, and so it played an important role in the magnetization in the partially disordered Cu 2 MnAl. In the disordered Cu 2 MnSn, however, the ordering effect was very small. It is supposed to be difficult for the A2 structure to transform into the L2 1 structure by the enhanced diffusion. (auth.)

  11. Carrier removal and defect behavior in p-type InP

    Science.gov (United States)

    Weinberg, I.; Swartz, C. K.; Drevinsky, P. J.

    1992-01-01

    A simple expression, obtained from the rate equation for defect production, was used to relate carrier removal to defect production and hole trapping rates in p-type InP after irradiation by 1-MeV electrons. Specific contributions to carrier removal from defect levels H3, H4, and H5 were determined from combined deep-level transient spectroscopy (DLTS) and measured carrier concentrations. An additional contribution was attributed to one or more defects not observed by the present DLTS measurements. The high trapping rate observed for H5 suggests that this defect, if present in relatively high concentration, could be dominant in p-type InP.

  12. Hole-capture properties of the electron-irradiation-induced deep-level H5 in p-type InP: A charge-controlled bistable model

    International Nuclear Information System (INIS)

    Bretagnon, T.; Bastide, G.; Rouzeyre, M.

    1989-01-01

    The electron-induced irradiated defect H 5 in Zn-doped p-type InP is an unusual hole trap, since its temperature-independent weak-hole capture cross section, σ c ∼10 -21 cm 2 , is 6 orders of magnitude lower than the value obtained from thermal-emission rates. We present a charge-controlled bistable configuration-coordinate diagram that explains this large difference and accounts for the optical-absorption properties. In addition, a microscopic D In n+ -Zn - defect, made by pairing under electrostatic attraction of the ionized acceptor Zn - and of a positively charged primitive defect D In n+ of the In sublattice, is tentatively proposed as a plausible complex at the origin of H 5

  13. Modification of structural and magnetic properties of soft magnetic multi-component metallic glass by 80 MeV {sup 16}O{sup 6+} ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kane, S.N., E-mail: kane_sn@yahoo.com [School of Physics, D.A. University, Khandwa Road Campus, Indore 452001 (India); Shah, M.; Satalkar, M.; Gehlot, K. [School of Physics, D.A. University, Khandwa Road Campus, Indore 452001 (India); Kulriya, P.K.; Avasthi, D.K. [Inter-University Accelerator Centre, P.O. Box No. 10502, Aruna Asaf Ali Marg, New Delhi 110067 (India); Sinha, A.K. [Raja Ramanna Centre for Advanced Technology, P.O. CAT, Indore 452013 (India); Modak, S.S. [Physics Department, Jaypee University of Eng. & Tech., A-B Road, Raghogarh, Guna 473226 (India); Ghodke, N.L.; Reddy, V.R. [UGC-DAE CSR, University Campus, Khandwa Road, Indore 452001 (India); Varga, L.K. [RISSPO, Hungarian Academy of Sciences, P.O. Box 49, 1525 Budapest (Hungary)

    2016-07-15

    Effect of 80 MeV {sup 16}O{sup 6+} ion irradiation in amorphous Fe{sub 77}P{sub 8}Si{sub 3}C{sub 5}Al{sub 2}Ga{sub 1}B{sub 4} alloy is reported. Electronic energy loss induced modifications in the structural and, magnetic properties were monitored by synchrotron X-ray diffraction (SXRD), Mössbauer and, magnetic measurements. Broad amorphous hump seen in SXRD patterns reveals the amorphous nature of the studied specimens. Mössbauer measurements suggest that: (a) alignment of atomic spins within ribbon plane, (b) changes in average hyperfine field suggests radiation-induced decrease in the inter atomic distance around Mössbauer (Fe) atom, (c) hyperfine field distribution confirms the presence of non-magnetic elements (e.g. – B, P, C) in the first near-neighbor shell of the Fe atom, thus reducing its magnetic moment, and (d) changes in isomer shift suggests variation in average number of the metalloid near neighbors and their distances. Minor changes in soft magnetic behavior – watt loss and, coercivity after an irradiation dose of 2 × 10{sup 13} ions/cm{sup 2} suggests prospective application of Fe{sub 77}P{sub 8}Si{sub 3}C{sub 5}Al{sub 2}Ga{sub 1}B{sub 4} alloy as core material in accelerators (radio frequency cavities).

  14. High temperature superconductors for fusion magnets -influence of neutron irradiation

    International Nuclear Information System (INIS)

    Chudy, M.; Eisterer, M.; Weber, H. W.

    2010-01-01

    In this work authors present the results of study of influence of neutron irradiation of high temperature superconductors for fusion magnets. High temperature superconductors (type of YBCO (Yttrium-Barium-Copper-Oxygen)) are strong candidates to be applied in the next step of fusion devices. Defects induced by fast neutrons are effective pinning centres, which can significantly improve critical current densities and reduce J c anisotropy. Due to induced lattice disorder, T c is reduced. Requirements for ITER (DEMO) are partially achieved at 64 K.

  15. Fe+ ion irradiation induced changes in structural and magnetic properties of iron films

    Directory of Open Access Journals (Sweden)

    K. Papamihail

    2016-12-01

    Full Text Available 490keV Fe+ ion irradiation of 200nm thick Fe films was found to induce both structural and magnetic changes. Both, the lattice constant and the grain size increase as a function of dose and both properties follow the same power law. Irradiation induces a depth dependent magnetic profile consisting of two sublayers. The top Fe sublayer has a magnetic moment higher than that of the Fe before the irradiation whereas the bottom sublayer lower. The two sublayers are connected with the effects of Fe+ irradiation, i.e. the top sublayer with the depth in which mainly radiation damage occurs whereas the bottom one with the implantation of impinging Fe+ ions. The magnetic moments of the two sublayers have a non-monotonous variation with irradiation dose depicting a maximum for the top sublayer and a minimum for the bottom one at 96.2 dpa (‘displacements per atom’. The magnetic moment enhancement/reduction is discussed in relation with the atomic volume variation in the case of atom displacements and/or implantation effects.

  16. Technology development of p-type microstrip detectors with radiation hard p-spray isolation

    International Nuclear Information System (INIS)

    Pellegrini, G.; Fleta, C.; Campabadal, F.; Diez, S.; Lozano, M.; Rafi, J.M.; Ullan, M.

    2006-01-01

    A technology for the fabrication of p-type microstrip silicon radiation detectors using p-spray implant isolation has been developed at CNM-IMB. The p-spray isolation has been optimized in order to withstand a gamma irradiation dose up to 50 Mrad (Si), which represents the ionization radiation dose expected in the middle region of the SCT-Atlas detector of the future Super-LHC during 10 years of operation. The best technological options for the p-spray implant were found by using a simulation software package and dedicated calibration runs. Using the optimized technology, detectors have been fabricated in the Clean Room facility of CNM-IMB, and characterized by reverse current and capacitance measurements before and after irradiation. The average full depletion voltage measured on the non-irradiated detectors was V FD =41±3 V, while the leakage current density for the microstrip devices at V FD +20 V was 400 nA/cm 2

  17. Electron-irradiation induced changes in structural and magnetic properties of Fe and Co based metallic glasses

    Energy Technology Data Exchange (ETDEWEB)

    Kane, S.N., E-mail: kane_sn@yahoo.com [School of Physics, D.A. University, Khandwa Road Campus, Indore 452001 (India); Satalkar, M., E-mail: satalkar.manvi@gmail.com [School of Physics, D.A. University, Khandwa Road Campus, Indore 452001 (India); Ghosh, A.; Shah, M. [School of Physics, D.A. University, Khandwa Road Campus, Indore 452001 (India); Ghodke, N. [UGC-DAE CSR, University Campus, Khandwa Road, Indore 452001 (India); Pramod, R.; Sinha, A.K.; Singh, M.N.; Dwivedi, J. [Raja Ramanna Centre for Advanced Technology, P.O. CAT, Indore 452013 (India); Coisson, M.; Celegato, F.; Vinai, F.; Tiberto, P. [INRIM, Electromagnetism Division, Strada Delle Cacce 91, I-10135 TO (Italy); Varga, L.K. [RISSPO, Hungarian Academy of Sciences, P.O. Box 49, 1525 Budapest (Hungary)

    2014-12-05

    Highlights: • Enhancement of Ms by low electron irradiation dose in Fe-based alloy. • Variation of magnetic properties by electron irradiation induced ordered phase. • Electron irradiation alters TM-TM distance and, magnetic properties. - Abstract: Electron-irradiation induced changes in structural and, magnetic properties of Co{sub 57.6}Fe{sub 14.4}Si{sub 4.8}B{sub 19.2}Nb{sub 4}, Fe{sub 72}Si{sub 4.8}B{sub 19.2}Nb{sub 4} and, Co{sub 72}Si{sub 4.8}B{sub 19.2}Nb{sub 4} metallic glasses were studied using magnetic hysteresis and, synchrotron X-ray diffraction measurements. Results reveal composition dependent changes of magnetic properties in electron irradiated metallic glasses. A low electron irradiation dose (15 kGy) enhances saturation magnetization (up to 62%) in Fe-based alloy (Fe{sub 72}Si{sub 4.8}B{sub 19.2}Nb{sub 4}). Synchrotron XRD measurements reveal that electron irradiation transforms the amorphous matrix to a more ordered phase, accountable for changes in magnetic properties.

  18. Irradiated radiation dose measurements of multilayer mirrors and permanent magnets used at FELI facilities

    International Nuclear Information System (INIS)

    Wakisaka, K.; Tongu, H.; Okuma, S.; Oshita, E.; Wakita, K.; Takii, T.; Tomimasu, Takio

    1997-01-01

    Recently the operation time of the free electron laser (FEL) user's facilities is close on three thousand hours per year. Cavity mirrors of their optical resonators and permanent magnets of their undulators are used under high intensity radiation field along their high current electron beam lines. Among these mirrors and permanent magnets, multilayer mirrors and Nd-Fe-B permanent magnets are not so strong against radiation damage compared with Au-coated copper mirrors and Sm-Co permanent magnets. A radiation damage on Ta 2 O 5 /SiO 2 mirrors was found for the first time after about fifty hours visible FEL operation at the FELI. The damage is due to irradiated bremsstrahlung and intracavity FEL. However, radiation damages on Nd-Fe-B permanent magnets were already reported compared with Sm-Co ones using high energy neutrons, protons, deuterons and 60 Coγ-rays. Mixed irradiation effects of 85-MeV electrons, bremsstrahlung and 60 Coγ-rays and of 17-MeV electrons and 60 Coγ-rays were also studied. The latest results show that the magnetic flux loss of Nd-Fe-B is 2% at an absorbed dose of 10 MGy. The present work was carried out to study the irradiated dose distributions near the multilayer mirrors and Nd-Fe-B permanent magnets with thermoluminescence dosimeters (TLDs). The irradiated dose to the cavity mirrors used in Linac-based FEL experiment is estimated to be 0.3 MGray for fifty hours irradiation. The irradiated dose to the Nd-Fe-B magnets is estimated to be 16 MGray for 2 thousand hours operation. The decrease of their magnetic flux due to 16 MGray is estimated to be about 3%. These dose monitorings are useful to reduce irradiated dosages to the mirrors and the permanent magnets as low as possible and to estimate their safety lifetimes. (author)

  19. Role of wild-type p53 in apoptotic and non-apoptotic cell death induced by X-irradiation and heat treatment in p53-mutated mouse M10 cells

    International Nuclear Information System (INIS)

    Ito, Atsushi; Nakano, Hisako; Shinohara, Kunio

    2010-01-01

    The sensitizing effects of wild-type p53 on X-ray-induced cell death and on heat-induced apoptosis in M10, a radiosensitive and Trp53 (mouse p53 gene)-mutated lymphoma cell line which dies through necrosis by X-irradiation, were investigated using three M10 derived transfectants with wild-type TP53 (human p53 gene). Cell death was determined by colony formation and/or dye exclusion test, and apoptosis was detected as the changes in nuclear morphology by Giemsa staining. Expression of wild-type p53 protein increased radiosensitivity of cell death as determined by both clonogenic and dye exclusion assays. This increase in radiosensitivity was attributable largely to apoptosis induction in addition to a small enhancement of necrosis. Interestingly neither pathway to cell death was accompanied by caspase-3 activation. On the other hand, heat-induced caspase-3 dependent apoptotic cell death without transfection was further increased by the transfection of wild-type p53. In conclusion, the introduction of wild-type p53 enhanced apoptotic cell death by X-rays or heat via different mechanisms that do or do not activate caspase-3, respectively. In addition, p53 also enhanced the X-ray-induced necrosis in M10 cells. (author)

  20. Application of neutron transmutation doping method to initially p-type silicon material.

    Science.gov (United States)

    Kim, Myong-Seop; Kang, Ki-Doo; Park, Sang-Jun

    2009-01-01

    The neutron transmutation doping (NTD) method was applied to the initially p-type silicon in order to extend the NTD applications at HANARO. The relationship between the irradiation neutron fluence and the final resistivity of the initially p-type silicon material was investigated. The proportional constant between the neutron fluence and the resistivity was determined to be 2.3473x10(19)nOmegacm(-1). The deviation of the final resistivity from the target for almost all the irradiation results of the initially p-type silicon ingots was at a range from -5% to 2%. In addition, the burn-up effect of the boron impurities, the residual (32)P activity and the effect of the compensation characteristics for the initially p-type silicon were studied. Conclusively, the practical methodology to perform the neutron transmutation doping of the initially p-type silicon ingot was established.

  1. Space charge sign inversion and electric field reconstruction in 24 GeV/c proton-irradiated MCZ Si p+-n(TD)-n+ detectors processed via thermal donor introduction

    International Nuclear Information System (INIS)

    Li, Z.; Verbitskaya, E.; Carini, G.; Chen, W.; Eremin, V.; Gul, R.; Haerkoenen, J.; Li, M.

    2009-01-01

    The aim of this study is the evaluation of radiation effects in detectors based on p-type magnetic czochralski (MCZ) Si that was converted to n-type by thermal donor (TD) introduction. As-processed p + -p-n + detectors were annealed at 430 deg. C resulting in p + -n(TD)-n + structures. The space charge sign and the electric field distribution E(x) in MCz Si p + -n(TD)-n + detectors irradiated by 24 GeV/c protons were analyzed using the data on the current pulse response and the Double Peak (DP) electric field distribution model for heavily irradiated detectors. The approach considers an irradiated detector as a structure with three regions in which the electric field depends on the coordinate, and the induced current pulse response arises from the drift process of free carriers in the detector with variable electric field. Reconstruction of the E(x) profile from the pulse response shapes is performed employing a new method for DP electric field reconstruction. This method includes: (a) a direct extraction of charge loss due to trapping and (b) the fitting of a simulated pulse response to the 'corrected' pulse by adjusting the electric field profiles in the three regions. Reconstruction of E(x) distribution showed that in the diodes irradiated by a proton fluence of (2-4)x10 14 p/cm 2 space charge sign inversion has occurred. This is the evidence that the influence of 24 GeV/c proton radiation on MCz Si p + -n(TD)-n + detectors is similar to that on p + -n-n + detectors based on FZ or diffusion oxygenated n-type Si.

  2. γ-ray irradiation effect on magnetic properties of electromagnetic Fe-Si sheets

    International Nuclear Information System (INIS)

    Harara, W.

    1994-11-01

    The present work investigates the effect of γ-ray irradiation on the relative and differential magnetic permeabilities of electromagnetic steel sheets. The experimental work was carried out using transformer Fe-Si (97-3%) sheets. The sheets have two different forms E and I> The magnetic field dependence on the relative permeability as well as on the differential permeability before and after irradiation were measured. The measurements show that the relative permeability values of the sheets after irradiation in the region of rotation of magnetization domains were decreased whereas the value of their differential permeability around each working point remains unchangeable. (author). 7 refs., 14 figs., 6 tabs

  3. A comparison study on of tumor cell-killing effects between low-dose-rate β-irradiation of 32P and γ-irradiation of 60Co

    International Nuclear Information System (INIS)

    Feng Huiru; Tian Jiahe; Ding Weimin; Zhang Jinming; Chen Yingmao

    2004-01-01

    The paper is to elucidate radiobiological characteristics and radiobiological mechanism in killing tumor cells with low dose rate β-rays and high dose rate γ-rays. HeLa cells were exposed to low-rate β-irradiation of 32 P or high-dose-rate γ-irradiation of 60 Co. Cell response-patterns were compared between two the types of radiations in terms of their inhibition of cell proliferation and cell cycle blockage, evaluated by trypanblue excluded method and flow cytometry, respectively. Results show that there is a different way in growth inhibition effect on HeLa cells between low-dose-rate irradiation of 32 P and high-dose-rate irradiation of 60 Co γ. In exposure to 32 P, the inhibition of cell proliferation in HeLa cell was a prolong course, whereas and the effect was in a more serious and quick way in 60 Co irradiation. Cell cycle arrest in G 2 phase induced by 32 P was lower and more prolong than that induced by 60 Co. The inhibition effect on tumor cells between the two types of radiations is different. Impaired DNA repair system by continuous low-dose-rate radiation might contribute to the final radiation effect of 32 P

  4. Functionalization and magnetization of carbon nanotubes using Co-60 gamma-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Chen, C.Y.; Fu, M.J.; Tsai, C.Y. [Division of Isotope Application, Institute of Nuclear Energy Research, Atomic Energy Council, P.O. BOX 3-27 Longtan, Taoyuan County 32546, Taiwan (R.O.C.) (China); Lin, F.H. [Institute of Biomedical Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan (R.O.C.) (China); Chen, K.Y., E-mail: chenky@iner.gov.tw [Division of Isotope Application, Institute of Nuclear Energy Research, Atomic Energy Council, P.O. BOX 3-27 Longtan, Taoyuan County 32546, Taiwan (R.O.C.) (China)

    2014-10-01

    Functionalized magnetic carbon nanotubes (CNTs) can be used in the biological and biomedical fields as biosensors, drug delivery systems, etc., which makes research into processes for manufacturing modified CNTs quite important. In this paper, Co-60 gamma irradiation is shown to be an effective tool for fabricating functionalized and magnetized CNTs. After the Co-60 gamma irradiation, the presence of carboxylic functional groups on the CNT walls was confirmed by their Fourier transform infrared spectra, and the presence of Fe{sub 3}O{sub 4} was verified by the X-ray diffraction patterns. The functionalized and magnetized CNTs produced using Co-60 gamma irradiation have excellent dispersion properties. The techniques for functionalizing and magnetizing CNTs are introduced in this paper, and applications of the modified CNTs will be reported after more data are gathered. - Highlights: Dispersion ability of carbon nanotubes (CNTs) was improved by functionalization. CNTs were easily manipulated by precipitation of magnetic nanoparticles. Our product can be used as versatile biosensor substrate for biomarker screening.

  5. Contribution of caspase-3 differs by p53 status in apoptosis induced by X-irradiation

    International Nuclear Information System (INIS)

    Kobayashi, Daisuke; Tokino, Takashi; Watanabe, Naoki

    2001-01-01

    We investigated the effect of p53 status on involvement of caspase-3 activation in cell death induced by X-irradiation, using rat embryonic fibroblasts (REFs) transduced with a temperature-sensitive mutant (mt) p53 gene. Cells with wild-type (wt) p53 showed greater resistance to X-irradiation than cells with mt p53. In cells with wt p53, X-irradiation-induced apoptosis was not inhibited by the caspase-3 inhibitor acetyl-L-aspartyl-L-methionyl-L-glutaminyl-L-aspartyl-aldehyde (Ac-DMQD-CHO) and caspase-3 activity was not elevated following X-irradiation, although induction of p53 and p21/WAF-1 protein was observed. In contrast, irradiated cells with mt p53 showed 89% inhibition of cell death with Ac-DMQD-CHO and 98% inhibition with the antioxidant N-acetyl-L-cysteine (NAC). In cells with mt p53, caspase-3 activity was increased approximately 5 times beyond baseline activity at 24 h after irradiation. This increase was almost completely inhibited by NAC. However, inhibition of caspase-3 by Ac-DMQD-CHO failed to decrease production of reactive oxygen species by cells with mt p53. Differential involvement of caspase-3 is a reason for differences in sensitivity to X-irradiation in cells with different p53 status. Caspase-3 activation appears to occur downstream from generation of reactive oxygen species occurring independently of wt p53 during X-irradiation-induced cell death. (author)

  6. Change in properties of superconducting magnet materials by fusion neutron irradiation

    International Nuclear Information System (INIS)

    Nishimura, Arata; Nishijima, Shigehiro; Takeuchi, Takao; Nishitani, Takeo

    2007-01-01

    A fusion reactor will generate a lot of high energy neutron and much energy will be taken out of the neutrons by a blanket system. Since some neutrons will stream out of a plasma vacuum vessel through neutral beam injection ports and penetrate a blanket system, a superconducting magnet system, which provides high magnetic field to confirm high energy particles, will be irradiated by a certain amount of neutrons. By developing the new NBI system or by reducing the penetration, the neutron fluence to the superconducting magnet will be able to be reduced. However, it is not easy to achieve the lower streaming and penetration at the present. Therefore, investigations on irradiation behavior of superconducting magnet materials are desired and some novel researches have been performed from 1970s. In general, the critical current of the superconducting wire increases under fast neutron environment comparing with that of the non-irradiated wire, and then decreased to almost zero as an increase of neutron fluence. On the other hand, the critical temperature of the wire starts to get down around 10 22 n/m 2 of neutron fluence and the temperature margin will be decreased during the operation by the neutron irradiation. In this paper, some aspects of irradiated materials will be overviewed and general tendency will be discussed focussing on knock-on effect of fast neutron and long range ordering of A15 compounds

  7. Radiation safety in 'install and operate type' irradiator

    International Nuclear Information System (INIS)

    Sahoo, D.K.; Kohli, A.K.

    2003-01-01

    Install and operate type irradiator has been designed to carry out radiation processing of various food products as well as medical products. It is a category 1 type batch irradiator. This paper brings out the radiation safety aspects of this irradiator. Comparison has been made with conveyor type category IV irradiators, which are more common in use for commercial purposes. The design has many features that make it a very safe, convenient and economical method for processing of all items that are permitted and amenable for gamma radiation processing. (author)

  8. High-energy electron irradiation of NdFeB permanent magnets: Dependence of radiation damage on the electron energy

    Energy Technology Data Exchange (ETDEWEB)

    Bizen, Teruhiko [JASRI SPring-8, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan)]. E-mail: bizen@spring8.or.jp; Asano, Yoshihiro [JASRI SPring-8, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); RIKEN SPring-8 Center, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Marechal, Xavier-Marie [JASRI SPring-8, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Seike, Takamitsu [JASRI SPring-8, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Aoki, Tsuyoshi [JASRI SPring-8, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Fukami, Kenji [JASRI SPring-8, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Hosoda, Naoyasu [JASRI SPring-8, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Yonehara, Hiroto [JASRI SPring-8, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Takagi, Tetsuya [JASRI SPring-8, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Hara, Toru [RIKEN SPring-8 Center, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Tanaka, Takashi [RIKEN SPring-8 Center, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Kitamura, Hideo [RIKEN SPring-8 Center, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan)

    2007-05-11

    High-energy electron-beam bombardment of Nd{sub 2}Fe{sub 14}B-type permanent magnets induces radiation damage characterized by a drop in the magnetic field. Experiments carried out at the SPring-8 booster synchrotron, with 4, 6, and 8 GeV electrons, show that the drop in magnetic field is energy dependent. Electromagnetic shower simulations suggest that most of the radiation damage happens in a small region around the irradiation axis, and that the contribution of neutrons with large scattering angles or with low energies to the magnetic field change is small.

  9. High-energy electron irradiation of NdFeB permanent magnets: Dependence of radiation damage on the electron energy

    International Nuclear Information System (INIS)

    Bizen, Teruhiko; Asano, Yoshihiro; Marechal, Xavier-Marie; Seike, Takamitsu; Aoki, Tsuyoshi; Fukami, Kenji; Hosoda, Naoyasu; Yonehara, Hiroto; Takagi, Tetsuya; Hara, Toru; Tanaka, Takashi; Kitamura, Hideo

    2007-01-01

    High-energy electron-beam bombardment of Nd 2 Fe 14 B-type permanent magnets induces radiation damage characterized by a drop in the magnetic field. Experiments carried out at the SPring-8 booster synchrotron, with 4, 6, and 8 GeV electrons, show that the drop in magnetic field is energy dependent. Electromagnetic shower simulations suggest that most of the radiation damage happens in a small region around the irradiation axis, and that the contribution of neutrons with large scattering angles or with low energies to the magnetic field change is small

  10. Magnetic, thermal and luminescence properties in room-temperature nanosecond electron-irradiated various metal oxide nanopowders

    Science.gov (United States)

    Sokovnin, S. Yu; Balezin, M. E.; Il’ves, V. G.

    2018-03-01

    By means of pulsed electron beam evaporation in vacuum of targets non-magnetic, in bulk state, Al2O3 and YSZ (ZrO2-8% Y2O3) oxides, magnetic nanopowders (NPs) with a high specific surface were produced. The NPs were subsequently irradiated in air by electrons with energy of 700 keV, using a URT-1 accelerator for 15 and 30 minutes. The magnetic, thermal, and pulsed cathodoluminescence (PCL) characteristics of NPs were measured before and after irradiation. It was established that the electron irradiation non-monotonically changes the magnetization of the pristine samples. To the contrary, a clear correlation between the intensity of PCL and the irradiation doses is found in the oxides. There was a decrease in the intensity of PCL after irradiation. Luminescent and thermal properties reflect the transformation of structural defects in NPs more strongly after the exposure to a pulsed electron beam in comparison with corresponding changes of the NPs magnetic response.

  11. Synthesis and spectroscopic characterization of magnetic hydroxyapatite nanocomposite using ultrasonic irradiation

    Science.gov (United States)

    Gopi, D.; Ansari, M. Thameem; Shinyjoy, E.; Kavitha, L.

    2012-02-01

    Nowadays magnetic hydroxyapatite (m-HAP) has potential applications in biomedicine more especially for bone cancer treatment. In this paper the functionalization of the hydroxyapatite (HAP) with magnetite nanoparticle (MNP) through ultrasonic irradiation technique is reported and its spectral investigation has been carried out. The ultrasonic irradiation with two different frequencies of 28 kHz and 35 kHz at the power of 150 and 320 W, respectively, was employed for the synthesis of m-HAP. The ultrasound irradiation of 35 kHz at 320 W shows the efficient diffusion of MNP to the HAP host matrix leads to the formation of m-HAP. The ultrasonic irradiation technique does not require stabilizers as in the case of coprecipitation method hence the final product of pure m-HAP is obtained. The X-ray diffraction pattern shows the formation of magnetite nanoparticles which are functionalized with hydroxyapatite host matrix. The vibrating sample magnetometer curve exhibits the super paramagnetic property of the samples and the saturation magnetization ( Ms) value of the functionalized magnetic hydroxyapatite. The Ms value is found to be much less than that of pure magnetite nanoparticle and this decrement in Ms is due to the hindrance of magnetic domain of the particles with HAP. The portrayed Raman spectra discriminate between the m-HAP and MNP with corresponding vibrational modes of frequencies. The transmission electron micrograph shows excellent morphology of functionalized m-HAP in nanometer range. The atomic force microscopic investigation shows the 3-dimensional view of crust and trench shape of m-HAP. All these results confirm the formation of magnetic hydroxyapatite nanocomposite with typical magnetic property for biological applications.

  12. Effect of sulphur-doping on the formation of deep centers in n-type InP under irradiation

    International Nuclear Information System (INIS)

    Kol'chenko, T.I.; Lomako, V.M.; Moroz, S.E.

    1988-01-01

    Effect of sulfur-doping on the efficiency of electron trap formation in InP under irradiation was studied using deep level capacity nonstationary spectroscopy method (DLCNS). Structures with Schottky barrier based on epitaxial InP films with ∼10μm thickness (n 0 =8x10 14 -6x10 17 cm -3 ) were irradiated with 60 Co γ-quanta at 40 deg C; the particle flux intensity made up ∼10 12 cm -2 xs -1 . Experimental results presented allow one to conclude that InP doping with sulfur up to n 0 =6x10 17 cm -3 in contrast to the case of silicon doping does not produce a notable effect on the electron trap formation efficiency under irradiation. The observed reduction of configuration-bistable M-center introduction rate in samples with n 0 >10 16 cm -3 is explained by the change of filling of E c -0.12 eV level belonging to unknown X defect

  13. Irradiation of Nd-Fe-B permanent magnets with APS bending magnet x-rays and 60Co γ-rays

    International Nuclear Information System (INIS)

    Alderman, J.; Job, P. K.; Puhl, J.

    2000-01-01

    The Advanced Photon Source (APS), as well as other third-generation synchrotron light sources, uses permanent magnets in the insertion devices to produce x-rays for scientific research. When placed in a high-energy storage ring, these permanent magnets are subjected to irradiation from synchrotron radiation, high-energy bremsstrahlung, and bremsstrahlung-produced photoneutrons. Previous investigations have exhibited varying degrees of degradation in the intensity of magnetization of these magnets due to irradiation from electron beams, 60 Co γrays, and high-energy neutrons. The APS specifically uses Nd-Fe-B permanent magnets in their insertion devices. Although no detectable radiation-induced demagnetization has been observed in the APS insertion devices so far, partial demagnetization has been observed in at least one insertion device at the European Synchrotron Radiation Facility (ESRF), where Nd-Fe-B permanent magnets are also used

  14. Dose selenomethionine have radio-protective effect on cell lines with wild type p53?

    International Nuclear Information System (INIS)

    Tsuji, K.; Hagihira, T.; Ohnishi, K.; Ohnishi, T.; Matsumoto, H.

    2003-01-01

    Full text: Selenium compounds are known to have cancer preventive effects. It is reported recently that selenium in the form of selenomethionine (SeMet) can protect cells with wild type p53 from UV-induced cell killing by activating the DNA repair mechanism of p53 tumor suppressor protein via redox factor Ref1 by reducing p53 cysteine residue 275 and 277. In contrast, SeMet has no protective effect on UV-induced cell killing in p53-null cells. If SeMet also has protective effect in cells with wild type p53 on cell killing by photon irradiation, SeMet can be used as normal tissue radio-protector. We examined the effect of SeMet on cell killing by X-ray irradiation in several cell lines with different p53 status at exponentially growing phase. Cell lines used in this experiment were as follows: H1299/neo; human lung cancer cell line of p53 null type tranfected with control vector with no p53, H1299/wp53; wild type p53 transfected counterpart. A172/neo; human glioblastoma cell line with wild type p53, A172/mp53-248; mp53-248 (248-mutant, ARG >TRP) transfected counterpart. SAS/neo; human tongue cancer cell line with wild type p53, and SAS/mp53-248; mp53-248 transfected counterpart. Cells were subcultured at monolayer in D-MEM containing 10% FBS. Survivals of the cells were determined by colony forming ability. Ten-MV linac X-ray was used to irradiate the cells. Exponentially growing cells were incubated with 20μM of SeMet for 15 hours before irradiation. After 24 hours exposure of SeMet, cells were incubated up to two weeks in growth medium for colony formation. Twenty-four hours exposure of 20μM of SeMet had no cytotoxicity on these cell lines. SeMet had no modification effect on cell killing by photon irradiation in H1299/neo, H1299/wp53, SAS/neo, SAS/mp53-248, and A172/mp53-248. On the other hand, SeMet sensitized A172/neo in radiation cell killing. The effects of p53 on interaction of SeMet and photon irradiation differ according to cell lines

  15. Hierarchical heterostructures of p-type bismuth oxychloride nanosheets on n-type zinc ferrite electrospun nanofibers with enhanced visible-light photocatalytic activities and magnetic separation properties.

    Science.gov (United States)

    Sun, Yucong; Shao, Changlu; Li, Xinghua; Guo, Xiaohui; Zhou, Xuejiao; Li, Xiaowei; Liu, Yichun

    2018-04-15

    P-type bismuth oxychloride (p-BiOCl) nanosheets were uniformly grown on n-type zinc ferrite (n-ZnFe 2 O 4 ) electrospun nanofibers via a solvothermal technique to form hierarchical heterostructures of p-BiOCl/n-ZnFe 2 O 4 (p-BiOCl/n-ZnFe 2 O 4 H-Hs). The density and loading amounts of the BiOCl nanosheets with exposed {0 0 1} facets were easily controlled by adjusting the reactant concentration in the solvothermal process. The p-BiOCl/n-ZnFe 2 O 4 H-Hs exhibited enhanced visible-light photocatalytic activities for the degradation of Rhodamine B (RhB). The apparent first-order rate of the p-BiOCl/n-ZnFe 2 O 4 H-Hs and its normalized constant were about 12.6- and 8-fold higher than pure ZnFe 2 O 4 nanofibers. This suggests that both the improved charge separation efficiency from the uniform p-n heterojunctions and the enlarged active surface sites from the hierarchical structures increase the photocatalytic performances. Furthermore, the p-BiOCl/n-ZnFe 2 O 4 H-Hs could be efficiently separated from the solution with an external magnetic field via the ferromagnetic behavior of ZnFe 2 O 4 nanofibers. The magnetic p-BiOCl/n-ZnFe 2 O 4 H-Hs with enhanced visible-light photocatalytic performances might have potential applications in water treatment. Copyright © 2018. Published by Elsevier Inc.

  16. Effect of gamma irradiation on the structural and magnetic properties of Co–Zn spinel ferrite nanoparticles

    International Nuclear Information System (INIS)

    Raut, Anil V.; Kurmude, D.V.; Shengule, D.R.; Jadhav, K.M.

    2015-01-01

    Highlights: • Co–Zn ferrite nanoparticles were examined before and after γ-irradiation. • Single phase cubic spinel structure of Co–Zn was confirmed by XRD data. • The grain size was reported in the range of 52–62 nm after γ-irradiation. • Ms, Hc, n B were reported to be increased after gamma irradiation. - Abstract: In this work, the structural and magnetic properties of Co 1−x Zn x Fe 2 O 4 (0.0 ≤ x ≤ 1.0) ferrite nanoparticles were studied before and after gamma irradiation. The as-synthesized samples of Co–Zn ferrite nanoparticles prepared by sol–gel auto-combustion technique were analysed by XRD which suggested the single phase; cubic spinel structure of the material. Crystal defects produced in the spinel lattice were studied before and after Co 60 γ-irradiation in a gamma cell with a dose rate of 0.1 Mrad/h in order to report the changes in structural and magnetic properties of the Co–Zn ferrite nanoparticles. The average crystallite size (t), lattice parameter (α) and other structural parameters of gamma-irradiated and un-irradiated Co 1−x Zn x Fe 2 O 4 spinel ferrite system was calculated from XRD data. The morphological characterizations were performed using scanning electron microscopy (SEM). The magnetic properties were measured using pulse field hysteresis loop tracer by applying magnetic field of 1000 Oe, and the analysis of data obtained revealed that the magnetic property such as saturation magnetization (Ms), coecivity (Hc), magneton number (n B ) etc. magnetic parameters were increased after irradiation

  17. Defect reactions on the phosphorus sublattice in low-temperature electron-irradiated InP

    International Nuclear Information System (INIS)

    Sibille, A.; Suski, J.

    1985-01-01

    This Rapid Communication describes several thermally or electronically stimulated defect reactions involving the dominant deep centers in low-temperature (25--300 K) electron-irradiated InP. Some of these reactions result in an increased concentration of the centers, thereby revealing the existence of a secondary production mechanism of the related defects. Low-energy irradiations allows one to select the type of the ejected atom (P) and gives direct evidence that only a phosphorus species, interstitial or vacancy, is involved in the creation-reaction-annealing events

  18. Biologic effect of exogenous wild p53 combined with irradiation on human melanoma cell lines with different p53 status

    International Nuclear Information System (INIS)

    Min Fengling; Zhang Hong; Li Wenjian; Liu Bing; Zhou Qingming; Duan Xin; Gao Qingxiang

    2007-01-01

    Objective: To investigate the effect of low dose irradiation on gene transfer efficiency and the effect of adenoviral-mediated exogenous P53 overexpression on apoptosis and radiosensitivity of radioresistant human melanoma cell lines A375(wild type p53)and WM983a(mutant type p53). Methods: Control vector, a replication deficient recombinant adenoviral vector containing a CMV promoter and green fluorescent protein (AdCMV-GFP), was used to transfect A375 cells and WM983a cells preirradiated with or without 1 Gy X-ray. The transduction efficiency of GFP gene was determined with fluorescence microscope directly. These two types of cells irradiated by 1 Gy X-ray were transfected with a replication deficient recombinant adenoviral vector carrying human wild p53 (AdCMV-p53), and mRNA level was detected by RT-PCR. The cell cycle delay and the expression of exogenous P53 were detected using flow cytometry (FCM) at different times after transfection. Tunel technique was used to detect cell apoptosis. The radiosensivity of A375 and WM983a cells after p53 transduction was analyzed by colony formation. Results: It is found that 1 Gy irradiation increased the gene transfection efficiency of A375 and WM983a cells. The expression of exogenous P53 was found to range from 60% to 80% among transfected cells during the first three days after transduction and then declined continuously down to the control level on day 10. G 1 cell cycle arrest was also observed after p53 gene transduction. WM983a cells transfected with p53 showed higher sensitivity to X-ray-induced cell killing than A375 cells. Conclusions: It is indicated that low dose of ionizing radiation can improve gene transfection efficiency of A375 and WM983a cells mediated by adenovirus vector. Althrough the overexpresion of exogenous p53 may not inhibit cell growth and induce apoptosis of melanoma cell line A375 and WM983a irt vitro, the two cell lines are much more sensitive to cell death induced by irradiation. It is

  19. Effect of gamma irradiation on the structural and magnetic properties of Co–Zn spinel ferrite nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Raut, Anil V., E-mail: nano9993@gmail.com [Vivekanand Arts, Sardar Dalipsingh Commerce and Science College, Aurangabad 431004, (M.S.) India (India); Kurmude, D.V. [Milind College of Science, Aurangabad 431004, (M.S.) India (India); Shengule, D.R. [Vivekanand Arts, Sardar Dalipsingh Commerce and Science College, Aurangabad 431004, (M.S.) India (India); Jadhav, K.M. [Department of Physics, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad 431004, (M.S.) India (India)

    2015-03-15

    Highlights: • Co–Zn ferrite nanoparticles were examined before and after γ-irradiation. • Single phase cubic spinel structure of Co–Zn was confirmed by XRD data. • The grain size was reported in the range of 52–62 nm after γ-irradiation. • Ms, Hc, n{sub B} were reported to be increased after gamma irradiation. - Abstract: In this work, the structural and magnetic properties of Co{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} (0.0 ≤ x ≤ 1.0) ferrite nanoparticles were studied before and after gamma irradiation. The as-synthesized samples of Co–Zn ferrite nanoparticles prepared by sol–gel auto-combustion technique were analysed by XRD which suggested the single phase; cubic spinel structure of the material. Crystal defects produced in the spinel lattice were studied before and after Co{sup 60} γ-irradiation in a gamma cell with a dose rate of 0.1 Mrad/h in order to report the changes in structural and magnetic properties of the Co–Zn ferrite nanoparticles. The average crystallite size (t), lattice parameter (α) and other structural parameters of gamma-irradiated and un-irradiated Co{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} spinel ferrite system was calculated from XRD data. The morphological characterizations were performed using scanning electron microscopy (SEM). The magnetic properties were measured using pulse field hysteresis loop tracer by applying magnetic field of 1000 Oe, and the analysis of data obtained revealed that the magnetic property such as saturation magnetization (Ms), coecivity (Hc), magneton number (n{sub B}) etc. magnetic parameters were increased after irradiation.

  20. Solar Irradiance Variability is Caused by the Magnetic Activity on the Solar Surface.

    Science.gov (United States)

    Yeo, Kok Leng; Solanki, Sami K; Norris, Charlotte M; Beeck, Benjamin; Unruh, Yvonne C; Krivova, Natalie A

    2017-09-01

    The variation in the radiative output of the Sun, described in terms of solar irradiance, is important to climatology. A common assumption is that solar irradiance variability is driven by its surface magnetism. Verifying this assumption has, however, been hampered by the fact that models of solar irradiance variability based on solar surface magnetism have to be calibrated to observed variability. Making use of realistic three-dimensional magnetohydrodynamic simulations of the solar atmosphere and state-of-the-art solar magnetograms from the Solar Dynamics Observatory, we present a model of total solar irradiance (TSI) that does not require any such calibration. In doing so, the modeled irradiance variability is entirely independent of the observational record. (The absolute level is calibrated to the TSI record from the Total Irradiance Monitor.) The model replicates 95% of the observed variability between April 2010 and July 2016, leaving little scope for alternative drivers of solar irradiance variability at least over the time scales examined (days to years).

  1. Information for irradiation and post-irradiation of the silicide fuel element prototype P-07

    International Nuclear Information System (INIS)

    Abbate, Maximo J.; Sbaffoni, Maria M.

    2003-01-01

    Included in the 'Silicides' Project, developed by the Nuclear Fuels Department of the National Atomic Energy Commission (CNEA), it is foreseen the qualification of this type of fuel for research reactors in order to be used in the Argentine RA-3 reactor and to confirm the CNEA as an international supplier. The paper presents basic information on several parameters corresponding to the new silicide prototype, called P-07, to be taken into account for its irradiation, postirradiation and qualification. (author)

  2. Design practice and operational experience of highly irradiated, high-performance normal magnets

    International Nuclear Information System (INIS)

    Schultz, J.H.

    1982-09-01

    The limitations of high performance magnets are discussed in terms of mechanical, temperature, and electrical limits. The limitations of magnets that are highly irradiated by neutrons, gamma radiation, or x radiation are discussed

  3. Photocurrent generation in lateral graphene p-n junction created by electron-beam irradiation

    KAUST Repository

    Yu, Xuechao; Shen, Youde; Liu, Tao; Wu, Tao; Jie Wang, Qi

    2015-01-01

    Graphene has been considered as an attractive material for optoelectronic applications such as photodetectors owing to its extraordinary properties, e.g. broadband absorption and ultrahigh mobility. However, challenges still remain in fundamental and practical aspects of the conventional graphene photodetectors which normally rely on the photoconductive mode of operation which has the drawback of e.g. high dark current. Here, we demonstrated the photovoltaic mode operation in graphene p-n junctions fabricated by a simple but effective electron irradiation method that induces n-type doping in intrinsic p-type graphene. The physical mechanism of the junction formation is owing to the substrate gating effect caused by electron irradiation. Photoresponse was obtained for this type of photodetector because the photoexcited electron-hole pairs can be separated in the graphene p-n junction by the built-in potential. The fabricated graphene p-n junction photodetectors exhibit a high detectivity up to ~3 × 1010 Jones (cm Hz1/2 W−1) at room temperature, which is on a par with that of the traditional III–V photodetectors. The demonstrated novel and simple scheme for obtaining graphene p-n junctions can be used for other optoelectronic devices such as solar cells and be applied to other two dimensional materials based devices.

  4. Photocurrent generation in lateral graphene p-n junction created by electron-beam irradiation

    KAUST Repository

    Yu, Xuechao

    2015-07-08

    Graphene has been considered as an attractive material for optoelectronic applications such as photodetectors owing to its extraordinary properties, e.g. broadband absorption and ultrahigh mobility. However, challenges still remain in fundamental and practical aspects of the conventional graphene photodetectors which normally rely on the photoconductive mode of operation which has the drawback of e.g. high dark current. Here, we demonstrated the photovoltaic mode operation in graphene p-n junctions fabricated by a simple but effective electron irradiation method that induces n-type doping in intrinsic p-type graphene. The physical mechanism of the junction formation is owing to the substrate gating effect caused by electron irradiation. Photoresponse was obtained for this type of photodetector because the photoexcited electron-hole pairs can be separated in the graphene p-n junction by the built-in potential. The fabricated graphene p-n junction photodetectors exhibit a high detectivity up to ~3 × 1010 Jones (cm Hz1/2 W−1) at room temperature, which is on a par with that of the traditional III–V photodetectors. The demonstrated novel and simple scheme for obtaining graphene p-n junctions can be used for other optoelectronic devices such as solar cells and be applied to other two dimensional materials based devices.

  5. Effect of neutron and gamma irradiation on magnetic bubble memories

    International Nuclear Information System (INIS)

    Cambou, B.

    1981-06-01

    Many years of research preceeded the introduction of magnetic bubble memories (M.B.M.) into the memory components market. They are used as bulk storage memories principally for their non volatile characteristics under irradiation. A physical and technological description of MBM is given in the first part of the text together with the results of work on their vulnerability when subjected to irradiation. Permanent damage caused by neutrons and gamma radiation on thin magnetic layers is then studied. A theoretical analysis on the stability of bubbles based on the results of pulsed laser experiments is given. The stability of the information stored in a commercially available MBM subjected to neutron and gamma irradiation (MBM - TIB 203 of 92 kBits, Texas) is described in the last part of the text. The vulnerability thresholds determined for the MBM are too high for them to be used in a radioactive environment with an improved electronic control system [fr

  6. Effect of UV C irradiation on P53 in FADD+/+ and FADD-/- cells

    International Nuclear Information System (INIS)

    Matic, Igor; Radnic, Maja; Marijanovic, Inga; Furcic, Ivana; Nagy, Biserka

    2008-01-01

    not mutant-specific. Allele-specific PCR detection of P53 in genomic DNA from UV-irradiated knockout and wild type cells were analyzed by gel electrophoresis.The results indicated that the mutant-specific primers (154-155, 175-176 and 275) didn't amplified 119-, 55- and 134-base pair (bp) products, unexpectedly, from irradiated FADD +/+ and FADD -/- cell DNAs as well as expected from non-radiated FADD +/+ and FADD -/- cell DNAs. In contrast, the mutant-specific primer for codon 270 amplified 134-base pair product from irradiated from FADD +/+ and FADD -/- cell DNAs. Because FADD is required for elimination of UV-irradiated cells, its loss could inhibit apoptosis and lead to expansion of apoptosis defective cells that contain P53 mutations. The data presented here suggest that loss of FADD expression and loss of wild type P53 function due to mutations can inhibit apoptosis and lead to the expansion of UV carcinogenesis. (author)

  7. Magnetic resonance thermometry for monitoring photothermal effects of interstitial laser irradiation

    Science.gov (United States)

    Goddard, Jessica; Jose, Jessnie; Figueroa, Daniel; Le, Kelvin; Liu, Hong; Nordquist, Robert E.; Hode, Tomas; Chen, Wei R.

    2012-03-01

    Selective photothermal interaction using dye-assisted non-invasive laser irradiation has limitations when treating deeper tumors or when the overlying skin is heavily pigmented. We developed an interstitial laser irradiation method to induce the desired photothermal effects. An 805-nm near-infrared laser with a cylindrical diffuser was used to treat rat mammary tumors by placing the active tip of the fiber inside the target tumors. Three different power settings (1.0 to 1.5 watts) were applied to treat animal tumors with an irradiation duration of 10 minutes. The temperature distributions of the treated tumors were measured by a 7.1-Tesla magnetic resonance imager using proton resonance frequency (PRF) method. Three-dimensional temperature profiles were reconstructed and assessed using PRF. This is the first time a 7.1-Tesla magnetic resonance imager has been used to monitor interstitial laser irradiation via PRF. This study provides a basic understanding of the photothermal interaction needed to control the thermal damage inside tumor using interstitial laser irradiation. It also shows that PRF can be used effectively in monitoring photothermal interaction. Our long-term goal is to develop a PRF-guided laser therapy for cancer treatment.

  8. study of irradiation effects on physical properties of some magnetic semiconductor materials

    International Nuclear Information System (INIS)

    Ahmed, I.A.A.

    2011-01-01

    The effect of gamma irradiation on the structure , magnetic and electrical properties of ferrite samples with chemical formula Mg x Cu 0.5-x Zn 0.5 Fe 2 O 4 (where x=0.0 , 0.2 and 0.4) were studied. The samples were prepared by conventional ceramic method.X-ray diffraction parameters, magnetization, initial permeability, electrical resistivity and dielectric constant were measured for the investigated samples before and after irradiation. Both magnetization and initial permeability were measured on toroidal samples used as transformer cores.The initial permeability (μ-i) was measured as a function of temperature at constant frequency of 10 khz and then curie temperatures (T c ) were determined. The Dc resistivity (ρ DC ) and the dielectric constant are measured on tablet form samples using the two probes technique.The real and imaginary parts of dielectric constant ε ' and ε '' were measured as a function of frequency within the range 45 Hz - 5 MHz before and after irradiation.

  9. Investigation on demagnetization of Nd2Fe14B permanent magnets induced by irradiation

    Science.gov (United States)

    Li, Zhefu; Jia, Yanyan; Liu, Renduo; Xu, Yuhai; Wang, Guanghong; Xia, Xiaobin

    2017-12-01

    Nd2Fe14B is an important component of insertion devices, which are used in synchrotron radiation sources, and could be demagnetized by irradiation. In the present study, the Monte Carlo code FLUKA was used to analyze the irradiation field of Nd2Fe14B, and it was confirmed that the main demagnetization particle was neutron. Nd2Fe14B permanent magnet samples were irradiated by Ar ions at different doses to simulate neutron irradiation damage. The hysteresis loops were measured using a vibrating sample magnetometer, and the microstructure evolutions were characterized by transmission electron microscopy. Moreover, the relationship between them was discussed. The results indicate that the decrease in saturated magnetization is caused by the changes in microstructure. The evolution of single crystals into an amorphous structure is the reason for the demagnetization phenomenon of Nd2Fe14B permanent magnets when considering its microscopic structure.

  10. Review of events at large pool-type irradiators

    International Nuclear Information System (INIS)

    Trager, E.A. Jr.

    1989-03-01

    Large pool-type gamma irradiators are used in applications such as the ''cold'' sterilization of medical and pharmaceutical supplies, and recent changes in federal regulations make it possible they will be used extensively in the preservation of foodstuffs. Because of this possible large increase in the use of irradiators, the Office of Nuclear Materials Safety and Safeguards was interested in knowing what events had occurred at irradiators. The event data would be used as background in developing new regulations on irradiators. Therefore, AEOD began a study of the operating experience at large, wet source storage gamma irradiators. The scope of the study was to assess all available operating information on large (≥ 250,000 curie), pool-type irradiators licensed by both the NRC and the Agreement States, and events at foreign facilities. The study found that about 0.12 events have been reported per irradiator-year. Most of these events were precursor events, in that there was no evidence of damage to the radioactive sources or degradation in the level of safety of the facility. Events with more significant impacts had a reported frequency of about 0.01 event per irradiator-year. However, the actual rate of occurrence of events of concern to the staff may be higher because there are few specific reporting requirements for events at irradiators. It is suggested that during development of a regulation for large pool-type irradiators consideration be given to specifying requirements for: reporting breakdowns in access control systems; periodic inspection of the source movement and suspension system; systems to detect source leakage and product contamination; allowable pool leakage; and feedback of information on operational events involving safety-important systems

  11. Superconductivity in Ti3P-type compounds

    International Nuclear Information System (INIS)

    Wills, J.O.; Hein, R.A.; Waterstrat, R.M.

    1978-01-01

    A study of 12 intermetallic A 3 B compounds which crsytallize in the tetragonal Ti 3 P-type structure has revealed five new superconductors with transition temperatures below 1 K: Zr 3 Si, Zr 3 Ge, Zr 3 P, V 3 P, and Nb 3 Ge (extrapolated from the alloy series Nb-Ge-As). In addition, two compounds, Zr 3 Sb and Ta 3 Ge, having the Ni 3 P structure type are found to be superconducting below 1 K. Within the Ti 3 P-type compounds, those with the lighter ''B'' elements in a given column of the Periodic Table have the higher transition temperatures. Critical-magnetic-field and electrical-resistivity data are reported for the superconducting Ti 2 P-type compound Nb 3 P, which permit one to estimate the Ginzburg-Landau kappa parameter and the electronic-specific-heat coefficient γ. The kappa value of 8.4 indicates that this material is type II, and the γ value of 1.3 mJ/mole K 2 for Nb 3 P is probably related to its low transition temperature relative to many A15 compounds

  12. Defect induced modification of structural, topographical and magnetic properties of zinc ferrite thin films by swift heavy ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Raghavan, Lisha [Department of Physics, Cochin University of Science and Technology, Cochin 682022 (India); Inter University Accelerator Center, New Delhi 110067 (India); Joy, P.A. [National Chemical Laboratory, Pune (India); Vijaykumar, B. Varma; Ramanujan, R.V. [School of Materials Science and Engineering, Nanyang Technological University (Singapore); Anantharaman, M.R., E-mail: mraiyer@gmail.com [Department of Physics, Cochin University of Science and Technology, Cochin 682022 (India)

    2017-04-01

    Highlights: • Zinc ferrite films exhibited room temperature ferrimagnetic property. • On ion irradiation amorphisation of films were observed. • The surface morphology undergoes changes with ion irradiation. • The saturation magnetisation decreases on ion irradiation. - Abstract: Swift heavy ion irradiation provides unique ways to modify physical and chemical properties of materials. In ferrites, the magnetic properties can change significantly as a result of swift heavy ion irradiation. Zinc ferrite is an antiferromagnet with a Neel temperature of 10 K and exhibits anomalous magnetic properties in the nano regime. Ion irradiation can cause amorphisation of zinc ferrite thin films; thus the role of crystallinity on magnetic properties can be examined. The influence of surface topography in these thin films can also be studied. Zinc ferrite thin films, of thickness 320 nm, prepared by RF sputtering were irradiated with 100 MeV Ag ions. Structural characterization showed amorphisation and subsequent reduction in particle size. The change in magnetic properties due to irradiation was correlated with structural and topographical effects of ion irradiation. A rough estimation of ion track radius is done from the magnetic studies.

  13. Effects of irradiation and mechanical stress on the superconducting properties of candidate magnet conductors

    International Nuclear Information System (INIS)

    Snead, C.L. Jr.; Luhman, T.

    1980-01-01

    The effects of radiation damage on the superconducting critical properties of candidate magnet materials are reviewed. Neutron, and charged-particle irradiation results are covered. The discussion is restricted to effects in NbTi and the A15-compound superconductors. The utility of these conductors in radiation fields is first explored by defining the magnitude of critical-property changes with the fluence of various irradiating particles. The physical mechanisms that couple the irradiation defects to the observed critical-property changes are discussed. Annealing/recovery data on irradiated materials are included where they pertain to the understanding of the physical mechanisms involved, and thereby to the desirability of magnet annealing in actual operating circumstances

  14. Influence of the interface on the magnetic properties of NiZn ferrite thin films treated by proton irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, X.D. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou 730000 (China); Guo, D.W. [Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou 730000 (China); Zhang, C.H., E-mail: c.h.zhang@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Fan, X.L.; Chai, G.Z. [Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou 730000 (China); Xue, D.S., E-mail: xueds@lzu.edu.cn [Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou 730000 (China)

    2015-09-01

    In order to systematically investigate the influence of the interface on the magnetic properties, polycrystalline NiZn ferrite thin films were irradiated with 60 keV proton in the dose range from 5 × 10{sup 12} to 5 × 10{sup 16} ions/cm{sup 2}. A non-destructive approach by proton irradiation was found to finely adjust the magnetic properties of polycrystalline NiZn ferrite thin films such as coercivity, perpendicular magnetic anisotropy as well as the effective g value. The coercivity is about 725 Oe for high proton dose ferrite, which is twice larger than the unirradiated one. The ferromagnetic resonance measurements indicated that perpendicular magnetic anisotropy and the effective g value increase with the irradiation dose. Our finding indicates that all modifications of these magnetic properties were associated with the change of interface due to the diffusion and the stress induced by proton irradiation. The change of the effective g value is a result of lattice expansion and the decrease of the magnetic dipole interaction between the columnar grains. This work provides a feasible way to tailor the magnetic properties of thin films by ion irradiation and promotes investigations for the stability of magnetic thin film devices in space or unclear radiation environments.

  15. Effect of 1.2 MeV argon ions irradiation on magnetic properties of ZnO

    International Nuclear Information System (INIS)

    Mishra, D.K.; Mohapatra, Jyoshnarani; Mahato, Banashree; Kumar, P.; Mitra, Amitav; Singh, S.K.; Kanjilal, D.

    2013-01-01

    Room temperature ferromagnetism in 1.2 MeV argon ions irradiated polycrystalline ZnO has been observed. The magnetic contribution in form of saturation magnetization is higher in sample irradiated with ion fluence of 1 × 10 15 ions/cm 2 . However, annealing of the defects at higher fluences of 5 × 10 15 ions/cm 2 reduce the magnetic contribution in comparison to the magnetic contribution of the lower fluences. The X-ray diffraction reveals that the degree of crystallinity decreases with the increase of ion fluences upto 1 × 10 15 ions/cm 2 and further it increases at a fluence of 5 × 10 15 ions/cm 2 . The inhomogeneous arrangement of grains and changes in their sizes with increasing ion fluences decrease the magnetic ordering of the system. The electron probe microstructure analyses and micro-Raman spectra of irradiated samples show in-homogeneity in zinc and oxygen ratio which is one of the causes to show ferromagnetism.

  16. Pre-irradiation at a low dose-rate blunted p53 response

    International Nuclear Information System (INIS)

    Takahashi, A.; Ohnishi, K.; Asakawa, I.; Tamamoto, T.; Yasumoto, J.; Yuki, K.; Ohnishi, T.; Tachibana, A.

    2003-01-01

    Full text: We have studied whether the p53-centered signal transduction pathway induced by acute radiation is interfered with chronic pre-irradiation at a low dose-rate in human cultured cells and whole body of mice. In squamous cell carcinoma cells, we found that a challenge irradiation with X-ray immediately after chronic irradiation resulted in lower levels of p53 than those observed after the challenge irradiation alone. In addition, the induction of p53-centered apoptosis and the accumulation of its related proteins after the challenge irradiation were strongly correlated with the above-mentioned phenomena. In mouse spleen, the induction of apoptosis and the accumulation of p53 and Bax were observed dose-dependently at 12 h after a challenge irradiation. In contrast, we found significant suppression of them induced by challenge irradiation at a high dose-rate when mice were pre-irradiated with chronic irradiation at a low dose-rate. These findings suggest that chronic pre-irradiation suppressed the p53 function through radiation-induced p53-dependent signal transduction processes. There are numerous papers about p53 functions in apoptosis, radiosensitivity, genomic instability and cancer incidence in cultured cells or animals. According to our data and other findings, since p53 can prevent carcinogenesis, pre-irradiation at a low dose-rate might enhance the predisposition to cancer. Therefore, it is possible that different maximal permissible dose equivalents for the public populations are appropriate. Furthermore, concerning health of human beings, studies of the adaptive responses to radiation are quite important, because the radiation response strongly depends on experience of prior exposure to radiation

  17. Fabrication and magnetic properties of granular Co/porous InP nanocomposite materials

    Directory of Open Access Journals (Sweden)

    Ma Li

    2011-01-01

    Full Text Available Abstract A novel Co/InP magnetic semiconductor nanocomposite was fabricated by electrodeposition magnetic Co nanoparticles into n-type porous InP templates in ethanol solution of cobalt chloride. The content or particle size of Co particles embedded in porous InP increased with increasing deposition time. Co particles had uniform distribution over pore sidewall surface of InP template, which was different from that of ceramic template and may open up new branch of fabrication of nanocomposites. The magnetism of such Co/InP nanocomposites can be gradually tuned from diamagnetism to ferromagnetism by increasing the deposition time of Co. Magnetic anisotropy of this Co/InP nanocomposite with magnetization easy axis along the axis of InP square channel was well realized by the competition between shape anisotropy and magnetocrystalline anisotropy. Such Co/InP nanocomposites with adjustable magnetism may have potential applications in future in the field of spin electronics. PACS: 61.46. +w · 72.80.Tm · 81.05.Rm · 75.75. +a · 82.45.Aa

  18. Fabrication and magnetic properties of granular Co/porous InP nanocomposite materials.

    Science.gov (United States)

    Zhou, Tao; Cheng, Dandan; Zheng, Maojun; Ma, Li; Shen, Wenzhong

    2011-03-31

    A novel Co/InP magnetic semiconductor nanocomposite was fabricated by electrodeposition magnetic Co nanoparticles into n-type porous InP templates in ethanol solution of cobalt chloride. The content or particle size of Co particles embedded in porous InP increased with increasing deposition time. Co particles had uniform distribution over pore sidewall surface of InP template, which was different from that of ceramic template and may open up new branch of fabrication of nanocomposites. The magnetism of such Co/InP nanocomposites can be gradually tuned from diamagnetism to ferromagnetism by increasing the deposition time of Co. Magnetic anisotropy of this Co/InP nanocomposite with magnetization easy axis along the axis of InP square channel was well realized by the competition between shape anisotropy and magnetocrystalline anisotropy. Such Co/InP nanocomposites with adjustable magnetism may have potential applications in future in the field of spin electronics.PACS: 61.46. +w · 72.80.Tm · 81.05.Rm · 75.75. +a · 82.45.Aa.

  19. Inter-individual and inter-cell type variation in residual DNA damage after in vivo irradiation of human skin

    International Nuclear Information System (INIS)

    Chua, Melvin Lee Kiang; Somaiah, Navita; Bourne, Sara; Daley, Frances; A'Hern, Roger; Nuta, Otilia; Davies, Sue; Herskind, Carsten; Pearson, Ann; Warrington, Jim; Helyer, Sarah; Owen, Roger; Yarnold, John; Rothkamm, Kai

    2011-01-01

    Purpose: The aim of this study was to compare inter-individual and inter-cell type variation in DNA double-strand break (DSB) repair following in vivo irradiation of human skin. Materials and methods: Duplicate 4 mm core biopsies of irradiated and unirradiated skin were collected from 35 patients 24 h after 4 Gy exposure using 6 MeV electrons. Residual DSB were quantified by scoring 53BP1 foci in dermal fibroblasts, endothelial cells, superficial keratinocytes and basal epidermal cells. Results: Coefficients of inter-individual variation for levels of residual foci 24 h after in vivo irradiation of skin were 39.9% in dermal fibroblasts, 44.3% in endothelial cells, 32.9% in superficial keratinocytes and 46.4% in basal epidermal cells (p < 0.001, ANOVA). In contrast, the coefficient of inter-cell type variation for residual foci levels was only 11.3% in human skin between the different epidermal and dermal cells (p = 0.034, ANOVA). Foci levels between the different skin cell types were correlated (Pearson's R = 0.855-0.955, p < 0.001). Conclusions: Patient-specific factors appear to be more important than cell type-specific factors in determining residual foci levels following in vivo irradiation of human skin.

  20. Neutron-irradiation facilities at the Intense Pulsed Neutron Source-I for fusion magnet materials studies

    International Nuclear Information System (INIS)

    Brown, B.S.; Blewitt, T.H.

    1982-01-01

    The decommissioning of reactor-based neutron sources in the USA has led to the development of a new generation of neutron sources that employ high-energy accelerators. Among the accelerator-based neutron sources presently in operation, the highest-flux source is the Intense Pulsed Neutron Source (IPNS), a user facility at Argonne National Laboratory. Neutrons in this source are produced by the interaction of 400 to 500 MeV protons with either of two 238 U target systems. In the Radiation Effects Facility (REF), the 238 U target is surrounded by Pb for neutron generatjion and reflection. The REF has three separate irradiation thimbles. Two thimbles provide irradiation temperatures between that of liquid He and several hundred degrees centigrade. The third thimble operates at ambient temperature. The large irradiation volume, the neutron spectrum and flux, the ability to transfer samples without warm up, and the dedication of the facilities during the irradiation make this ideally suited for radiation damage studies on components for superconducting fusion magnets. Possible experiments for fusion magnet materials are discussed on cyclic irradiation and annealing of stabilizers in a high magnetic field, mechanical tests on organic insulation irradiated at 4 K, and superconductors measured in high fields after irradiation

  1. Strong out-of-plane magnetic anisotropy in ion irradiated anatase TiO2 thin films

    Directory of Open Access Journals (Sweden)

    M. Stiller

    2016-12-01

    Full Text Available The temperature and field dependence of the magnetization of epitaxial, undoped anatase TiO2 thin films on SrTiO3 substrates was investigated. Low-energy ion irradiation was used to modify the surface of the films within a few nanometers, yet with high enough energy to produce oxygen and titanium vacancies. The as-prepared thin film shows ferromagnetism which increases after irradiation with low-energy ions. An optimal and clear magnetic anisotropy was observed after the first irradiation, opposite to the expected form anisotropy. Taking into account the experimental parameters, titanium vacancies as di-Frenkel pairs appear to be responsible for the enhanced ferromagnetism and the strong anisotropy observed in our films. The magnetic impurities concentrations was measured by particle-induced X-ray emission with ppm resolution. They are ruled out as a source of the observed ferromagnetism before and after irradiation.

  2. Radiation defects in electron-irradiated InP crystals

    International Nuclear Information System (INIS)

    Brailovskii, E.Yu.; Karapetyan, F.K.; Megela, I.G.; Tartachnik, V.P.

    1982-01-01

    The results are presented of formation and annealing of defects in InP crystals at 1 to 50 MeV electron irradiation. The recovery of electrical properties in the range of 77 to 970 K during annealing processes is studied. Five low temperature annealing states in n-InP and the reverse annealing in p-InP are observed at 77 to 300 K. Four annealing stages at temperatures higher than 300 K are present. When the electron energy is increased more complicated thermostable defects are formed, and at 50 MeV electron energy besides of the point defect clusters are formed, which anneal at temperatures of 800 to 970 K. It is shown that the peculiarities of the Hall mobility at irradiation and annealing are caused by the scattering centres E/sub c/ - 0.2 eV. The 'limiting' position of the Fermi level in electron irradiated InP crystals is discussed. (author)

  3. Radiation defects in electron-irradiated InP crystals

    Energy Technology Data Exchange (ETDEWEB)

    Brailovskii, E.Yu.; Karapetyan, F.K.; Megela, I.G.; Tartachnik, V.P. (AN Ukrainskoj SSR, Kiev. Inst. Yadernykh Issledovanij)

    1982-06-16

    The results are presented of formation and annealing of defects in InP crystals at 1 to 50 MeV electron irradiation. The recovery of electrical properties in the range of 77 to 970 K during annealing processes is studied. Five low temperature annealing states in n-InP and the reverse annealing in p-InP are observed at 77 to 300 K. Four annealing stages at temperatures higher than 300 K are present. When the electron energy is increased more complicated thermostable defects are formed, and at 50 MeV electron energy besides of the point defect clusters are formed, which anneal at temperatures of 800 to 970 K. It is shown that the peculiarities of the Hall mobility at irradiation and annealing are caused by the scattering centres E/sub c/ - 0.2 eV. The 'limiting' position of the Fermi level in electron irradiated InP crystals is discussed.

  4. Proton irradiation effects on deep level states in Mg-doped p-type GaN grown by ammonia-based molecular beam epitaxy

    Science.gov (United States)

    Zhang, Z.; Arehart, A. R.; Kyle, E. C. H.; Chen, J.; Zhang, E. X.; Fleetwood, D. M.; Schrimpf, R. D.; Speck, J. S.; Ringel, S. A.

    2015-01-01

    The impact of proton irradiation on the deep level states throughout the Mg-doped p-type GaN bandgap is investigated using deep level transient and optical spectroscopies. Exposure to 1.8 MeV protons of 1 × 1013 cm-2 and 3 × 1013 cm-2 fluences not only introduces a trap with an EV + 1.02 eV activation energy but also brings monotonic increases in concentration for as-grown deep states at EV + 0.48 eV, EV + 2.42 eV, EV + 3.00 eV, and EV + 3.28 eV. The non-uniform sensitivities for individual states suggest different physical sources and/or defect generation mechanisms. Comparing with prior theoretical calculations reveals that several traps are consistent with associations to nitrogen vacancy, nitrogen interstitial, and gallium vacancy origins, and thus are likely generated through displacing nitrogen and gallium atoms from the crystal lattice in proton irradiation environment.

  5. Magnetic properties changes of MnAs thin films irradiated with highly charged ions

    OpenAIRE

    Trassinelli , Martino; Gafton , V.; Eddrief , Mahmoud; Etgens , Victor H.; Hidki , S.; Lacaze , Emmanuelle; Lamour , Emily; Luo , X.; Marangolo , Massimiliano; Merot , Jacques; Prigent , Christophe; Reuschl , Regina; Rozet , Jean-Pierre; Steydli , S.; Vernhet , Dominique

    2013-01-01

    International audience; We present the first investigation on the effect of highly charged ion bombardment on a manganese arsenide thin film. The MnAs films, 150~nm thick, are irradiated with 90 keV Ne$^{9+}$ ions with a dose varying from $1.6\\times10^{12}$ to $1.6\\times10^{15}$~ions/cm$^2$. The structural and magnetic properties of the film after irradiation are investigated using different techniques, namely, X-ray diffraction, magneto-optic Kerr effect and magnetic force microscope. Prelim...

  6. Wood construction and magnetic characteristics of impregnated type magnetic wood

    International Nuclear Information System (INIS)

    Oka, Hideo; Hojo, Atsushi; Seki, Kyoushiro; Takashiba, Toshio

    2002-01-01

    The results of experiments involving the AC and DC magnetic characteristics of impregnated type magnetic wood were studied by taking into consideration the wood construction and fiber direction. The experimental results show that the sufficient amount of impregnated magnetic fluid varies depending on the fiber direction and length, and the grain face of the wood material. The impregnated type magnetic wood sample that is fully impregnated by magnetic fluid has a 60% saturation magnetization compared to the saturation magnetization of magnetic fluid. Samples for which the wood fiber direction was the same as the direction of the magnetic path had a higher magnetization intensity and permeability

  7. Neutron irradiation effects on magnetic properties of Fe-based ferromagnetic metallic glasses

    International Nuclear Information System (INIS)

    Miglierini, M.; Nasu, Saburo; Skorvanek, I.; Sitek, J.

    1992-01-01

    Transmission 57 Fe Moessbauer spectroscopy, J-H quasistatic hysteresis loop and AC susceptibility measurements are used to study effects of neutron irradiation on magnetic properties of Fe-based-ferromagnetic metallic glasses. Elastic stress centers are produced during the process of neutron irradiation as a result of atom mixing. Rearrangement of the atoms causes changes in the average value of the hyperfine field distribution and orientation of the net magnetic moment. They are shown to depend on the composition of the investigated samples. Cr-doped metallic glasses depict transition from the ferromagnetic to paramagnetic state at room temperature after neutron irradiation implying changes in the Curie temperature. The presence of Ni in the samples reduces the effects of radiation damage as revealed also from position lifetime data. Possible sources of a radiation damage are discussed using the results of γ-ray spectroscopy. (author)

  8. Neutron irradiation effects on magnetic properties of Fe-based ferromagnetic metallic glasses

    Energy Technology Data Exchange (ETDEWEB)

    Miglierini, M.; Nasu, Saburo (Osaka Univ., Toyonaka (Japan). Faculty of Science); Skorvanek, I.; Sitek, J.

    1992-04-01

    Transmission {sup 57}Fe Moessbauer spectroscopy, J-H quasistatic hysteresis loop and AC susceptibility measurements are used to study effects of neutron irradiation on magnetic properties of Fe-based-ferromagnetic metallic glasses. Elastic stress centers are produced during the process of neutron irradiation as a result of atom mixing. Rearrangement of the atoms causes changes in the average value of the hyperfine field distribution and orientation of the net magnetic moment. They are shown to depend on the composition of the investigated samples. Cr-doped metallic glasses depict transition from the ferromagnetic to paramagnetic state at room temperature after neutron irradiation implying changes in the Curie temperature. The presence of Ni in the samples reduces the effects of radiation damage as revealed also from position lifetime data. Possible sources of a radiation damage are discussed using the results of {gamma}-ray spectroscopy. (author).

  9. The effect of charge collection recovery in silicon p-n junction detectors irradiated by different particles

    International Nuclear Information System (INIS)

    Verbitskaya, E.; Abreu, M.; Anbinderis, P.; Anbinderis, T.; D'Ambrosio, N.; Boer, W. de; Borchi, E.; Borer, K.; Bruzzi, M.; Buontempo, S.; Casagrande, L.; Chen, W.; Cindro, V.; Dezillie, B.; Dierlamm, A.; Eremin, V.; Gaubas, E.; Gorbatenko, V.; Granata, V.; Grigoriev, E.; Grohmann, S.; Hauler, F.; Heijne, E.; Heising, S.; Hempel, O.; Herzog, R.; Haerkoenen, J.; Ilyashenko, I.; Janos, S.; Jungermann, L.; Kalesinskas, V.; Kapturauskas, J.; Laiho, R.; Li, Z.; Mandic, I.; De Masi, Rita; Menichelli, D.; Mikuz, M.; Militaru, O.; Niinikoski, T.O.; O'Shea, V.; Pagano, S.; Palmieri, V.G.; Paul, S.; Perea Solano, B.; Piotrzkowski, K.; Pirollo, S.; Pretzl, K.; Rato Mendes, P.; Ruggiero, G.; Smith, K.; Sonderegger, P.; Sousa, P.; Tuominen, E.; Vaitkus, J.; Da Via, C.; Wobst, E.; Zavrtanik, M.

    2003-01-01

    The recovery of the charge collection efficiency (CCE) at low temperatures, the so-called 'Lazarus effect', was studied in Si detectors irradiated by fast reactor neutrons, by protons of medium and high energy, by pions and by gamma-rays. The experimental results show that the Lazarus effect is observed: (a) after all types of irradiation; (b) before and after space charge sign inversion; (c) only in detectors that are biased at voltages resulting in partial depletion at room temperature. The experimental temperature dependence of the CCE for proton-irradiated detectors shows non-monotonic behaviour with a maximum at a temperature defined as the CCE recovery temperature. The model of the effect for proton-irradiated detectors agrees well with that developed earlier for detectors irradiated by neutrons. The same midgap acceptor-type and donor-type levels are responsible for the Lazarus effect in detectors irradiated by neutrons and by protons. A new, abnormal 'zigzag'-shaped temperature dependence of the CCE was observed for detectors irradiated by all particles (neutrons, protons and pions) and by an ultra-high dose of γ-rays, when operating at low bias voltages. This effect is explained in the framework of the double-peak electric field distribution model for heavily irradiated detectors. The redistribution of the space charge region depth between the depleted regions adjacent to p + and n + contacts is responsible for the 'zigzag'- shaped curves. It is shown that the CCE recovery temperature increases with reverse bias in all detectors, regardless of the type of radiation

  10. Ion irradiation effects in structural and magnetic properties of Co/Cu multilayers

    International Nuclear Information System (INIS)

    Sakamoto, Isao; Okazaki, Satoshi; Koike, Masaki; Honda, Shigeo

    2012-01-01

    400 keV Ar ion (the Ar ion) and 50 keV He ion (the He ion) irradiations were performed in order to elucidate roles of Co/Cu interfacial structures in physical origins of giant magnetoresistance (GMR) in the [Co (2 nm)/Cu (2 nm)] 30 multilayers (MLs). The magnetoresistance (MR) ratio after the Ar ion irradiation decreases abruptly with increasing Ar ion fluence. On the other hand, the MR ratio after the He ion irradiation decreases slowly with increasing He ion fluence. The Ar ion irradiation induces the decrease in the difference (R max − R sat ) between the maximum resistance (R max ) and the saturated resistance (R sat ) under in-plane magnetic field and the increase in the R sat , although the effect of the He ion irradiation is not remarkable. The decrease in the (R max − R sat ) rather than the increase in the R sat seems to be effective for the decrease in the MR ratios after the Ar ion and the He ion irradiation. The increase in the R sat implies the mixing of Co atoms in Cu layers. The antiferromagnetic coupling fraction (AFF) estimated from the magnetization curves after the Ar ion and the He ion irradiation shows the similar behavior with the MR ratio as a function of ion fluence. Therefore, although the degrees of the irradiation effects by the Ar ion and the He ions are different, we suggest the relation between the GMR and the AFF affected by the ion-induced interfacial structures accompanied with the atomic mixing in the interfacial region.

  11. Combined exposure of ELF magnetic fields and X-rays increased mutant yields compared with X-rays alone in pTN89 plasmids

    International Nuclear Information System (INIS)

    Koyama, Shin; Nakahara, Takehisa; Sakurai, Tomonori; Komatsubara, Yoshiki; Miyakoshi, Junji; Isozumi, Yasuhito

    2005-01-01

    We have examined mutations in the supF gene carried by pTN89 plasmids in Escherichia coli (E. coli) to examine the effects of extremely low frequency magnetic fields (ELFMFs) and/or X-rays to the plasmids. The plasmids were subjected to sham exposure or exposed to an ELFMF (5 mT), with or without X-ray irradiation (10 Gy). For the combined treatments, exposure to the ELFMF was immediately before or after X-ray irradiation. The mutant fractions were 0.94 x 10 -5 for X-rays alone, 1.58 x 10 -5 for an ELFMF followed by X-rays, and 3.64 x 10 -5 for X-rays followed by an ELFMF. Increased mutant fraction was not detected following exposure to a magnetic field alone, or after sham exposure. The mutant fraction for X-rays followed by an ELFMF was significantly higher than those of other treatments. Sequence analysis of the supF mutant plasmids revealed that base substitutions were dominant on exposure to X-rays alone and X-rays plus an ELFMF. Several types of deletions were detected in only the combined treatments, but not with X-rays alone. We could not find any mutant colonies in sham irradiated and an ELFMF alone treatment, but exposure to ELFMFs immediately before or after X-ray irradiation may enhance the mutations. Our results indicate that an ELFMF increases mutation and alters the spectrum of mutations. (author)

  12. Progress towards vertical transport study of proton-irradiated InAs/GaSb type-II strained-layer superlattice materials for space-based infrared detectors using magnetoresistance measurements

    Science.gov (United States)

    Malone, Mitchell C.; Morath, Christian P.; Fahey, Stephen; Klein, Brianna; Cowan, Vincent M.; Krishna, Sanjay

    2015-09-01

    InAs/GaSb type-II strained-layer superlattice (T2SLS) materials are being considered for space-based infrared detector applications. However, an inadequate understanding of the role of carrier transport, specifically the vertical mobility, in the radiation tolerance of T2SLS detectors remains. Here, progress towards a vertical transport study of proton-irradiated, p-type InAs/GaSb T2SLS materials using magnetoresistance measurements is reported. Measurements in the growth direction of square mesas formed from InAs/GaSb superlattice material were performed using two distinct contact geometries in a Kelvin mode setup at variable magnetic fields, ranging from -9 T to 9 T, and temperatures, ranging from 5 K and 300 K. The results here suggested multi-carrier conduction and a field-dependent series resistance from the contact layer were present. The implications of these results and the plans for future magnetoresistance measurements on proton-irradiated T2SLS materials are discussed.

  13. Pre-irradiation at a low dose-rate blunted p53 response

    International Nuclear Information System (INIS)

    Takahashi, Akihisa

    2002-01-01

    We investigated whether chronic irradiation at a low dose-rate interferes with the p53-centered signal transduction pathyway induced by radiation in human cultured cells and C57BL/6N mice. In in vitro experiments, we found that a challenge with X-ray irradiation immediately after chronic irradiation resulted in lower levels of p53 than those observed after the challenge alone in glioblastoma cells (A-172). In addition, the levels of p53-centered apoptosis and its related proteins after the challenge were strongly correlated with the above-mentioned phenomena in squamous cell carcinoma cells (SAS/neo). In in vivo experiments, the accumulation of p53 and Bax, and the induction of apoptosis were observed dose-dependently in mouse spleen at 12 h after a challenge with X-rays (3.0 Gy). However, we found significant suppression of p53 and Bax accumulation and the induction of apoptosis 12 h after challenge irradiation at 3.0 Gy with a high doses-rate following chronic pre-irradiation (1.5 Gy, 0.001 Gy/min). These findings suggest that chronic pre-irradiation suppressed the p53 function through radiation-induced signaling and/or p53 stability. (author)

  14. Optical properties of the main electron-irradiation-induced defects in p-type InP: Comparison with calculations for the isolated and acceptor-paired phosphorus vacancy

    International Nuclear Information System (INIS)

    Bretagnon, T.; Bastide, G.; Rouzeyre, M.; Delerue, C.; Lannoo, M.

    1990-01-01

    Optical capacitance spectroscopy and thermal annealing of defects have been used to study both the electron traps EP 1 ,E 11 and the dominant hole traps (H 3 -H 4 -H 4 ' ) produced by low-energy electron irradiation in Zn-doped p-type InP. This shows that the 1.1-eV onset in the photoionization cross sections (PCS's) previously attributed to (H 3 -H 4 ) is actually due to the unrelated electron trap EP 1 . The true PCS's σ p 0 of (H 3 ,H 4 ) are compared with PCS tight-binding Green's function calculations to test the earlier proposal that the (H 2 -H 3 -H 4 -H 4 ' ,E 11 ) series might arise from different states of (V P -Zn) complexes. The model yields an effective agreement as concerns both the energy location of the hole-levels series in the forbidden gap and the vanishingly small contribution to the PCS's of the four equivalent L valence-band minima. The proposal that E 11 might correspond to the ionization of an e state of the V P -Zn complex also agrees with the experimental observation of both optical transitions to the valence band and to the conduction band but cannot account for the midgap position of E 11

  15. P-stop isolation study of irradiated n-in-p type silicon strip sensors for harsh radiation environment

    CERN Document Server

    AUTHOR|(CDS)2084505

    2015-01-01

    In order to determine the most radiation hard silicon sensors for the CMS Experiment after the Phase II Upgrade in 2023 a comprehensive study of silicon sensors after a fluence of up to $1.5\\times10^{15} n_{eq}/cm^{2}$ corresponding to $3000 fb^{-1}$ after the HL-LHC era has been carried out. The results led to the decision that the future Outer Tracker (20~cm${<}R{<}$110~cm) of CMS will consist of n-in-p type sensors. This technology is more radiation hard but also the manufacturing is more challenging compared to p-in-n type sensors due to additional process steps in order to suppress the accumulation of electrons between the readout strips. One possible isolation technique of adjacent strips is the p-stop structure which is a p-type material implantation with a certain pattern for each individual strip. However, electrical breakdown and charge collection studies indicate that the process parameters of the p-stop structure have to be carefully calibrated in order to achieve a sufficient strip isolatio...

  16. Theoretical study of magnetic pattern replication by He+ ion irradiation through stencil masks

    International Nuclear Information System (INIS)

    Devolder, T.; Chappert, C.; Bernas, H.

    2002-01-01

    We have developed an irradiation technique that allows us to tune the magnetic properties of Co/Pt multilayers without affecting their roughness. The planarity and the ability to independently control nanostructure size and coercivity make our technique very appealing for magnetic recording. We study the irradiation-induced 1:1 replication of features drilled in a stencil mask. Both the 'gap' G between the magnetic film and the mask, and the aspect ratio (AR) of the mask features are analyzed, in view of the ion straggling in the mask resulting in collateral damages. Optimal gap is such that D<< G<< D/tan(α) (typically 0.1<< G<<25 μm), where the D is the feature size. The replication quality is best for AR≥3. Since the allowed gap interval is wide, we anticipate that mask fast positioning will be possible for the applications to magnetic recording

  17. Performance degradation of ferrofluidic feedthroughs in a mixed irradiation field

    Science.gov (United States)

    Simos, Nikolaos; Fernandes, S.; Mittig, Wolfgang; Pellemoine, Frederique; Avilov, M.; Kostin, M.; Mausner, L.; Ronningen, R.; Schein, M.; Bollen, G.

    2017-01-01

    Ferrofluidic feedthrough (FF) rotary seals containing either NdFeB or SmCo-type permanent magnets have been considered for use in the target and beam dump systems of the Facility for Rare Isotope Beams (FRIB). To evaluate their performance under irradiation three FF seals were irradiated in a mixed field consisting of fast neutrons, protons and γ-rays to an average absorbed dose of 0.2, 2.0, and 20.0 MGy at the Brookhaven Linac Isotope Producer facility (BLIP). The radiation types and energy profiles mimic those expected at the FRIB facility. Degradation of the operational performance of these devices due to irradiation is expected to be the result of the de-magnetization of the permanent magnets contained within the seal and the changes in the ferrofluid properties. Post-irradiation performance was evaluated by determining the ferrofluidic seal vacuum tightness and torque under static and dynamic conditions. The study revealed that the ferrofluidic feedthrough seal irradiated to a dose of 0.2 MGy maintained its vacuum tightness under both static and rotational condition while the one irradiated to a dose of 2.0 MGy exhibited signs of ferrofluid damage but no overall performance loss. At 20 MGy dose the effects of irradiation on the ferrofluid properties (viscosity and particle agglomeration) were shown to be severe. Furthermore, limited de-magnetization of the annular shaped Nd2Fe14B and Sm2Co17 magnets located within the irradiated FFs was observed for doses of 0.2 MGy and 20 MGy respectively.

  18. n/p-Type changeable semiconductor TiO{sub 2} prepared from NTA

    Energy Technology Data Exchange (ETDEWEB)

    Li Qiuye; Wang Xiaodong; Jin Zhensheng, E-mail: zhenshengjin@henu.edu.cn; Yang Dagang; Zhang Shunli; Guo Xinyong; Yang Jianjun; Zhang Zhijun [Henan University, Key Laboratory of Special Functional Materials (China)

    2007-10-15

    A novel kind of nano-sized TiO{sub 2} (anatase) was obtained by high-temperature (400-700 deg. C) dehydration of nanotube titanic acid (H{sub 2}Ti{sub 2}O{sub 4}(OH){sub 2}, NTA). The high-temperature (400-700 deg. C) dehydrated nanotube titanic acids (HD-NTAs) with a unique defect structure exhibited a p-type semiconductor behavior under visible-light irradiation ({lambda}{>=} 420nm, E{sub photon}=2.95 eV), whereas exhibited an n-type semiconductor behavior irradiated with UV light ({lambda}{>=} 365nm, E{sub photon}=3.40 eV)

  19. Effects of 3.1-MeV proton and 1-GeV Au-ion irradiation on the magnetic flux noise and critical current of YBa2Cu3O7-δ

    International Nuclear Information System (INIS)

    Shaw, T.J.; Clarke, J.; van Dover, R.B.; Schneemeyer, L.F.; White, A.E.

    1996-01-01

    We have used a dc superconducting quantum interference device to measure the spectral density of magnetic flux noise, S Φ (f), generated by vortex motion in crystals of YBa 2 Cu 3 O 7-δ (YBCO) both before and after irradiation with 3.1-MeV protons and 1-GeV Au ions. In addition, we have studied the effects of irradiation on the critical current J c of the same samples. Both types of irradiation reduced S Φ (f) at most temperatures and magnetic fields and increased J c at all temperatures and magnetic fields. By measuring S Φ (f) versus temperature, we extract the distribution of vortex pinning energies, D(U 0 ). Both crystals have peaks in D(U 0 ) near 0.1 eV and 0.2 eV before irradiation, and a much reduced peak near 0.1 eV after irradiation. The noise level after either kind of irradiation was substantially higher than in an unirradiated YBCO film. copyright 1996 The American Physical Society

  20. UV-irradiation potentiates the antimutagenicity of p-aminobenzoic and p-aminosalicylic acids in Salmonella typhimurium

    International Nuclear Information System (INIS)

    Gichner, T.; Baburek, I.; Veleminsky, J.; Kappas, A.

    1991-01-01

    UV-irradiation (254 nm, 10 or 20 J/cm 2 ) of p-aminobenzoic acid (PABA) and p-aminosalicylic acid (NaPAS) potentiated their antimuta-genicity towards N-methyl-N'-nitro-N-nitrosoguanide metagenesis in Salmonella typhimurium. Their inhibitory action towards the formation of mutagen N-methyl-N-mitrosourea from the nitrosation mixture of N-methylurea and nitrite was also increased by UV-irradiation. In contrast, UV-irradiated PABA exhibited no inhibitory effects towards the mutagenicity of sodium azide or 3-azidoglycerol. Neither PABA nor NaPAS not their UV-irradiation products were themselves mutagenic in the Ames assay. 13 refs.; 5 tabs

  1. Change of magnetic properties of nanocrystalline alloys under influence of external factors

    Science.gov (United States)

    Sitek, Jozef; Holková, Dominika; Dekan, Julius; Novák, Patrik

    2016-10-01

    Nanocrystalline (Fe3Ni1)81Nb7B12 alloys were irradiated using different types of radiation and subsequently studied by Mössbauer spectroscopy. External magnetic field of 0.5 T, electron-beam irradiation up to 4 MGy, neutron irradiation up to 1017 neutrons/cm2 and irradiation with Cu ions were applied on the samples. All types of external factors had an influence on the magnetic microstructure manifested as a change in the direction of the net magnetic moment, intensity of the internal magnetic field and volumetric fraction of the constituent phases. The direction of the net magnetic moment was the most sensitive parameter. Changes of the microscopic magnetic parameters were compared after different external influence and results of nanocrystalline samples were compared with their amorphous precursors.

  2. Apoptosis in spermatogonia irradiated P53 null mice

    International Nuclear Information System (INIS)

    Streit-Bianchi, M.; Hendry, J.H.; Roberts, S.A.; Morris, J.D.; Durgaryan, A.A.

    2007-01-01

    Complete text of publication follows. The exposure of germ cells to ionizing radiations is of concern both from high-dose therapeutic exposures and from low doses causing deleterious trans-generational mutations. P53 protein plays an important role in cellular damage and is expressed in the testis normally during meiosis, its expression being localised to the preleptotene and early/mid pachytene spermatocytes. P53 null mice, heterozygotes possessing a 129 Sv/C57BL6 genetic background and B6D2F1 mice have been irradiated to 1 and 2 Gy single doses. Fractionated exposures of 1+1 Gy at 4 hours interval were also carried out. Apoptosis induction, spermatogonia and spermatocytes survival were assessed by microscope analysis of histological samples at 4 to 96 hours after irradiation in time-course experiments. The same end-points were also assessed at 72 and 96 hours after irradiation to single doses in the region between 20cGy to 2Gy. A dose dependent level of p53 expression was observed at 4 hours after irradiation to 1 and 2 Gy which returned to normal level by 24 hours. Our data support a two process mode of apoptosis with a first wave around 12 hours followed by a second wave at 2-3 days. The first wave apoptosis is substantially reduced in p53 null mice whereas the second wave is reduced in B6D2F1 mice. The initial increase in apoptosis was delayed in some stages of the of germ cells development which were identified by the spermatids shape. Clear correlation exists between apoptosis and survival assessed in stage XI-XII Tubules 72 hours after irradiation. The data are in agreement with other data in literature indicating that irradiated spermatogonia die through apoptosis. The lack of apoptosis observed in p53 null mice results in a very high survival rate of daughter cells assessed later. Theses spermatocytes and the following progenitor cells are likely to carry mutations as most will not die in the smaller second wave of apoptosis observed 3 days after

  3. Characteristics of The Magnet Wheel As A Magnetic Levitation Device of Induction Type

    OpenAIRE

    藤井, 信男; 小川, 幸吉; 松本, 敏雄; Nobuo, FUJII; Kokichi, OGAWA; Toshio, MATSUMOTO; 九州大学; 大分大学; 安川電機; Kyushu University; Oita University; Yaskawa Electric Co., Ltd.

    1996-01-01

    A new type of magnetic wheel called the "magnet wheel" has been proposed. The magnet wheel has both magnetic levitation and linear drive functions combined into one. In the magnet wheel, the permanent magnets are rotated over the conducting plate so that an induction type of repulsive lift force is obtained. To produce thrust from the drag torque which is simultaneously induced with the lift force, the "tilt type" and "partial overlap type" magnet wheels have been proposed. Poor power factor ...

  4. F-type centers in neutron-irradiated AIN

    International Nuclear Information System (INIS)

    Atobe, Kozo; Honda, Makoto; Fukuoka, Noboru; Okada, Moritami; Nakagawa, Masuo.

    1990-01-01

    The production of point defects by neutron irradiation and thermal decay in sintered AIN polycrystal are investigated. The absorption band at 370 nm is observed after reactor neutron irradiation to a dose of 10 16 n/cm 2 (E > 0.1 MeV). The defect corresponding to the band is tentatively assigned as an F-type center from the optical absorption and electron spin resonance. (author)

  5. Effects of a low-energy proton irradiation on n+/p-AlInGaP solar cells

    International Nuclear Information System (INIS)

    Lee, H.S.; Yamaguchi, M.; Ekins-Daukes, N.J.; Khan, A.; Takamoto, T.; Imaizumi, M.; Ohshima, T.; Itoh, H.

    2006-01-01

    For the first time, by deep-level transient spectroscopy, 30keV proton irradiation-induced defects in n + /p-AlInGaP solar cells have been observed. After the 30keV proton irradiation, new deep-level defects such as two majority-carrier (hole) traps HP1 (E V +0.98eV, N T =3.8x10 14 cm -3 ) and HP2, and two minority-carrier (electron) traps EP1 (E C -0.71eV, N T =2.0x10 15 cm -3 ) and EP2 have been observed in p-AlInGaP. The introduction rate of majority-carrier trap center (HP1) is 380cm -1 , which is lower than that (1500cm -1 ) in 100keV proton-irradiated p-InGaP. From the minority-carrier injection annealing for HP1 defect and carrier concentration in 30keV proton-irradiated p-AlInGaP, HP1 defect is likely to act as a recombination center as well as a compensator center

  6. Irradiation-injured brain tissues can self-renew in the absence of the pivotal tumor suppressor p53 in the medaka (Oryzias latipes) embryo

    International Nuclear Information System (INIS)

    Yasuda, Takako; Nagata, Kento; Igarashi, Kento; Watanabe-Asaka, Tomomi; Oda, Shoji; Mitani, Hiroshi; Kimori, Yoshitaka

    2016-01-01

    The tumor suppressor protein, p53, plays pivotal roles in regulating apoptosis and proliferation in the embryonic and adult central nervous system (CNS) following neuronal injuries such as those induced by ionizing radiation. There is increasing evidence that p53 negatively regulates the self-renewal of neural stem cells in the adult murine brain; however, it is still unknown whether p53 is essential for self-renewal in the injured developing CNS. Previously, we demonstrated that the numbers of apoptotic cells in medaka (Oryzias latipes) embryos decreased in the absence of p53 at 12-24 h after irradiation with 10-Gy gamma rays. Here, we used histology to examine the later morphological development of the irradiated medaka brain. In p53-deficient larvae, the embryonic brain possessed similar vacuoles in the brain and retina, although the vacuoles were much smaller and fewer than those found in wild-type embryos. At the time of hatching (6 days after irradiation), no brain abnormality was observed. In contrast, severe disorganized neuronal arrangements were still present in the brain of irradiated wild-type embryos. Our present results demonstrated that self-renewal of the brain tissue completed faster in the absence of p53 than wild type at the time of hatching because p53 reduces the acute severe neural apoptosis induced by irradiation, suggesting that p53 is not essential for tissue self-renewal in developing brain. (author)

  7. The performance of the anthraquinone/p-Si and the pyridine/p-Si rectifying device under X-ray irradiation

    International Nuclear Information System (INIS)

    Şahin, Yılmaz; Aydoğan, Şakir; Ekinci, Duygu; Turut, Abdulmecit

    2016-01-01

    Some X-ray irradiation-induced electrical characteristics of the Au/anthraquinone/p-Si and the Au/pyridine/p-Si junction devices have been investigated. The experimental ideality factors increased for both devices with increasing irradiation dose from 25 Gy to 150 Gy. These values ranged from 1.10 to 1.52 for Au/anthraquinone/p-Si and from 1.46 to 1.77 for Au/pyridine/p-Si, respectively. Furthermore, the barrier height of Au/anthraquinone/p-Si increased with increasing irradiation dose from 0.75 to 0.91 eV, whereas it displayed about a constant value for Au/pyridine/p-Si. In addition, the series resistance of both devices increased with x-ray dose too. The increase in the series resistance with x-ray irradiation has been attributed to the decrease in the active dopant densities. It was seen that the ionization damage is effective on most of the junction characteristics. The leakage current of the Au/anthraquinone/p-Si device decreased with x-ray irradiation since the irradiation induced the formation of electron-hole pairs and hydroquinone structure, and thus some of them are trapped by the interface states. The degradation of the I-V curves of Au/pyridine/p-Si/Al device is attributed to the variation of the surface or interface states distribution for the devices. The reverse and forward bias currents relatively increased after x-ray irradiation because of the decrease in bulk lifetime. In addition, ATR-FTIR spectra of anthraquinone and pyridine films showed that pyridine is more stable than anthraquinone under x-ray irradiation. - Highlights: • Two junction devices based on organic materials were fabricated. • The effect of the x-ray irradiation on devices were examined. • Both devices showed x-irradiation-dependence.

  8. The performance of the anthraquinone/p-Si and the pyridine/p-Si rectifying device under X-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Şahin, Yılmaz [Department of Physics, Faculty of Sciences, University of Atatürk, 25240 Erzurum (Turkey); Aydoğan, Şakir, E-mail: saydogan@atauni.edu.tr [Department of Physics, Faculty of Sciences, University of Atatürk, 25240 Erzurum (Turkey); Ekinci, Duygu [Department of Chemistry, Faculty of Sciences, University of Atatürk, 25240 Erzurum (Turkey); Turut, Abdulmecit [Department of Engineering Physics, Faculty of Sciences, Istanbul Medeniyet University (Turkey)

    2016-11-01

    Some X-ray irradiation-induced electrical characteristics of the Au/anthraquinone/p-Si and the Au/pyridine/p-Si junction devices have been investigated. The experimental ideality factors increased for both devices with increasing irradiation dose from 25 Gy to 150 Gy. These values ranged from 1.10 to 1.52 for Au/anthraquinone/p-Si and from 1.46 to 1.77 for Au/pyridine/p-Si, respectively. Furthermore, the barrier height of Au/anthraquinone/p-Si increased with increasing irradiation dose from 0.75 to 0.91 eV, whereas it displayed about a constant value for Au/pyridine/p-Si. In addition, the series resistance of both devices increased with x-ray dose too. The increase in the series resistance with x-ray irradiation has been attributed to the decrease in the active dopant densities. It was seen that the ionization damage is effective on most of the junction characteristics. The leakage current of the Au/anthraquinone/p-Si device decreased with x-ray irradiation since the irradiation induced the formation of electron-hole pairs and hydroquinone structure, and thus some of them are trapped by the interface states. The degradation of the I-V curves of Au/pyridine/p-Si/Al device is attributed to the variation of the surface or interface states distribution for the devices. The reverse and forward bias currents relatively increased after x-ray irradiation because of the decrease in bulk lifetime. In addition, ATR-FTIR spectra of anthraquinone and pyridine films showed that pyridine is more stable than anthraquinone under x-ray irradiation. - Highlights: • Two junction devices based on organic materials were fabricated. • The effect of the x-ray irradiation on devices were examined. • Both devices showed x-irradiation-dependence.

  9. Irradiations under magnetic field. Measurement of resistivity sample irradiations between 100 and 500 deg C in a swimming-pool reactor

    International Nuclear Information System (INIS)

    Pauleve, J.; Marchand, A.; Blaise, A.

    1964-01-01

    An oven is described which enables the irradiation of small samples in the maximum neutron flux of a swimming-pool reactor of 15 MW (Siloe), at temperatures of between 100 and 500 deg.C defined to ± 0,5 deg.C, The oven is very simple from the technological point of view, and has a diameter of only 27 mm, This permits resistivity measurements to be carried out under irradiation in the reactor, or as another example, it enables irradiations in a magnetic field of 5000 oersteds, created by an immersed solenoid. (authors) [fr

  10. Effects of cavitation on damage calculations in ion-irradiated P7 alloy

    International Nuclear Information System (INIS)

    Sindelar, R.L.; Farrens, S.N.; Kulcinski, G.L.

    1985-01-01

    The purpose of this study is to investigate the effect of voids on the depth-dependent damage energy in ion-irradiated metals. Corrections to the dose at the swelling peak will be used to obtain the swelling rate of ion-irradiated 316-type stainless steels. Samples of the P7 alloy were ion-irradiated to four fluence levels up to a peak dose level of 100 dpa at 650 0 C. The depth-dependent void parameters extracted in cross section were used to model the effect of voids on the depth-dependent damage produced during 14 MeV nickel ion irradiation. An increase in the range of damage produced from the original foil surface for the target containing voids was modeled as a first-order correction to the damage profile. A second-order effect, void straggling, was shown to cause a time-dependent decrease in the damage rate at the peak swelling depth. Corrections applied to the dose at the peak swelling depth yield swelling rates approaching 0.7%/dpa

  11. Influence of an external magnetic field on damage by self-ion irradiation in Fe90Cr10 alloy

    Directory of Open Access Journals (Sweden)

    Fernando José Sánchez

    2016-12-01

    Full Text Available The effect of an external magnetic field (B=0.5 T on Fe90Cr10 specimens during Fe ion irradiation, has been investigated by means of Conversion Electron Mössbauer Spectroscopy (CEMS. The analysis has revealed significant differences in the average hyperfine magnetic field (=0.3 T between non-irradiated and irradiated samples as well as between irradiations made with B (w/ B and without B (w/o B. It is considered that these variations can be due to changes in the local environment around the probe nuclei (57Fe; where vacancies and Cr distribution play a role. The results indicate that the Cr distribution in the neighbourhood of the iron atoms could be changed by the application of an external field. This would imply that an external magnetic field may be an important parameter to take into account in predictive models for Cr behaviour in Fe–Cr alloys, and especially in fusion conditions where intense magnetic fields are required for plasma confinement.

  12. Singlet Ground State Magnetism: III Magnetic Excitons in Antiferromagnetic TbP

    DEFF Research Database (Denmark)

    Knorr, K.; Loidl, A.; Kjems, Jørgen

    1981-01-01

    The dispersion of the lowest magnetic excitations of the singlet ground state system TbP has been studied in the antiferromagnetic phase by inelastic neutron scattering. The magnetic exchange interaction and the magnetic and the rhombohedral molecular fields have been determined.......The dispersion of the lowest magnetic excitations of the singlet ground state system TbP has been studied in the antiferromagnetic phase by inelastic neutron scattering. The magnetic exchange interaction and the magnetic and the rhombohedral molecular fields have been determined....

  13. Effects of low-dose rate irradiation on two types of type II diabetes model mice

    International Nuclear Information System (INIS)

    Nomura, Takaji; Sakai, Kazuo

    2004-01-01

    The effects of low-dose rate gamma-irradiation were investigated in two mouse strains - C57BL/KsJ-db/db (db mouse) and AKITA (AKITA mouse)-for type II diabetes mellitus. Both strains develop the developed type II diabetes by about 8 weeks of age due to dysfunction of the insulin/insulin receptor. The db Mouse' shows obese and exhibits hyperinsulinism, and the onset of Type II diabetes like resembles that for Westerners. On the other hand, the AKITA mouse has exhibits disordered insulin secretion, and the diabetes such as resembles that of Asians. Ten-week old female mice, in groups of 8 or 12, were irradiated at 0.65 mGy/hr in the low-dose rate irradiation facility in the Low Dose Radiation Research Center. The level of urine glucose was measured with test slips. The urine glucose levels of all of the mice were highly elevated the beginning of the irradiation. In the irradiated group of db mice, three mice showed decrease in glucose level compare to the level of non-irradiated diabetes mice after 35, 52 or 80 weeks of irradiation. All had maintained a normal level thereafter. No such improvement in diabetes was ever observed in the 12 mice of in the non-irradiated control group. The AKITA mice, however, did not decrease the glucose level regardless of the irradiation. Both the db mice and AKITA mice had their lives prolonged their life by the irradiation. The survival rate of db mice at the age of 90 weeks was 75% in the irradiated group, but 50% in the non-irradiated group. The average life span was 104 weeks in the irradiated group and 87 weeks in the control group. Furthermore, a marked difference was furthermore observed in the appearance of the coat hair, skin, and tail; appearances were well preserved in the irradiated group. The average life span in the irradiated AKITA mice was also longer than that for the non-irradiated mice, 51 weeks and 41 weeks in the irradiated and non-irradiated group respectively. These results suggest that the low-dose irradiation

  14. Magnetic studies of current conduction and flux pinning in high-Tc cuprates: Virgin, irradiated, and oxygen deficient materials

    International Nuclear Information System (INIS)

    Thompson, J.R.; Civale, L.; Marwick, A.D.; Holtzberg, F.

    1992-09-01

    To increase the current density and pinning of magnetic flux in high temperature superconductors, defects with point-like and line-like geometries were created in controlled numbers using ion irradiation methods. Single crystals of Y 1 Ba 2 Cu 3 O 7 and Bi 2 Sr 2 Ca 1 Cu 2 0 8 superconductors were studied using dc magnetic methods. These studies showed greatly increased irreversibility in the vortex state magnetization and enhanced intragrain current density J c following irradiation. Linear defects, created by irradiation with energetic heavy ions, are particularly effective in pinning vortices at higher temperatures and magnetic fields. Further investigations of ''flux creep'' (the time dependence of magnetization) are well described by recent vortex glass and collective pinning theories. Complementary investigations have delineated the role of oxygen deficiency δ on pinning in aligned Y 1 Ba 2 Cu 3 O 7-δ materials

  15. 50 MeV, Li"3"+ - ion irradiation effect on magnetic ordering of Y"3"+ - substituted yttrium iron garnet

    International Nuclear Information System (INIS)

    Sharma, P. U.; Zankat, K. B.; Dolia, S. N.; Modi, K. B.

    2016-01-01

    This communication presents the effect of non-magnetic Y"3"+ ions substitution for magnetic Fe"3"+ ions and 50 MeV, Li"3"+ ion irradiation (fluence: 5 × 10"1"3 ions/cm"2) on magnetic ordering and Neel temperature of Y_3_+_xFe_5_-_xO_1_2 (x = 0.0, 0.2, 0.4 and 0.6) garnet system, studied by means of X-ray powder diffractometry and thermal variation of low field (0.5 Oe) ac susceptibility measurements. The un-irradiated compositions exhibit normal ferrimagnetic behavior with decrease in transition temperature (T_N) on increasing Y"3"+-concentration (x). The irradiated counterparts are characterized by tailing effect indicative of non-uniform effect of irradiation and lower value of T_N. The results have been discussed based on the weakening of magnetic exchange interactions and cumulative effect of redistribution of cations and fractional creation of localized paramagnetic centers resulting from swift heavy ion irradiation. The Neel temperatures and exchange integrals have been calculated theoretically.

  16. Heavy ion irradiation effects of brannerite-type ceramics

    International Nuclear Information System (INIS)

    Lian, J.; Wang, L.M.; Lumpkin, G.R.; Ewing, R.C.

    2002-01-01

    Brannerite, UTi 2 O 6 , occurs in polyphase Ti-based, crystalline ceramics that are under development for plutonium immobilization. In order to investigate radiation effects caused by α-decay events of Pu, a 1 MeV Kr + irradiation on UTi 2 O 6 , ThTi 2 O 6 , CeTi 2 O 6 and a more complex material, composed of Ca-containing brannerite and pyrochlore, was performed over a temperature range of 25-1020 K. The ion irradiation-induced crystalline-to-amorphous transformation was observed in all brannerite samples. The critical amorphization temperatures of the different brannerite compositions are: 970 K, UTi 2 O 6 ; 990 K, ThTi 2 O 6 ; 1020 K, CeTi 2 O 6 . The systematic increase in radiation resistance from Ce-, Th- to U-brannerite is related to the difference of mean atomic mass of A-site cation in the structure. As compared with the pyrochlore structure-type, brannerite phases are more susceptible to ion irradiation-induced amorphization. The effects of structure and chemical compositions on radiation resistance of brannerite-type and pyrochlore-type ceramics are discussed

  17. Sb2S3:C/CdS p-n junction by laser irradiation

    International Nuclear Information System (INIS)

    Arato, A.; Cardenas, E.; Shaji, S.; O'Brien, J.J.; Liu, J.; Castillo, G. Alan; Das Roy, T.K.; Krishnan, B.

    2009-01-01

    In this paper, we report laser irradiated carbon doping of Sb 2 S 3 thin films and formation of a p-n junction photovoltaic structure using these films. A very thin carbon layer was evaporated on to chemical bath deposited Sb 2 S 3 thin films of approximately 0.5 μm in thickness. Sb 2 S 3 thin films were prepared from a solution containing SbCl 3 and Na 2 S 2 O 3 at 27 deg. C for 5 h and the films obtained were highly resistive. These C/Sb 2 S 3 thin films were irradiated by an expanded laser beam of diameter approximately 0.5 cm (5 W power, 532 nm Verdi laser), for 2 min at ambient atmosphere. Morphology and composition of these films were analyzed. These films showed p-type conductivity due to carbon diffusion (Sb 2 S 3 :C) by the thermal energy generated by the absorption of laser radiation. In addition, these thin films were incorporated in a photovoltaic structure Ag/Sb 2 S 3 :C/CdS/ITO/Glass. For this, CdS thin film of 50 nm in thickness was deposited on a commercially available ITO coated glass substrate from a chemical bath containing CdCl 2 , sodium citrate, NH 4 OH and thiourea at 70 deg. C . On the CdS film, Sb 2 S 3 /C layers were deposited. This multilayer structure was subjected to the laser irradiation, C/Sb 2 S 3 side facing the beam. The p-n junction formed by p-Sb 2 S 3 :C and n-type CdS showed V oc = 500 mV and J sc = 0.5 mA/cm 2 under illumination by a tungsten halogen lamp. This work opens up a new method to produce solar cell structures by laser assisted material processing

  18. Point defects and magnetic properties of neutron irradiated MgO single crystal

    Directory of Open Access Journals (Sweden)

    Mengxiong Cao

    2017-05-01

    Full Text Available (100-oriented MgO single crystals were irradiated to introduce point defects with different neutron doses ranging from 1.0×1016 to 1.0×1020 cm-2. The point defect configurations were studied with X-ray diffuse scattering and UV-Vis absorption spectra. The isointensity profiles of X-ray diffuse scattering caused by the cubic and double-force point defects in MgO were theoretically calculated based on the Huang scattering theory. The magnetic properties at different temperature were measured with superconducting quantum interference device (SQUID. The reciprocal space mappings (RSMs of irradiated MgO revealed notable diffuse scattering. The UV-Vis spectra indicated the presence of O Frenkel defects in irradiated MgO. Neutron-irradiated MgO was diamagnetic at room temperature and became ferromagnetic at low temperature due to O Frenkel defects induced by neutron-irradiation.

  19. Effect of pH on paste properties of irradiated corn starch by gamma-rays

    International Nuclear Information System (INIS)

    Kume, Tamikazu; Aoki, Shohei; Kobayashi, Nobuo; Okuaki, Akira.

    1979-01-01

    The degradation of starch by γ-irradiation and the effect of pH on gelatinization of starch after irradiation were investigated. Paste viscosities were markedly affected by pH on gelatinization and a decrease in the viscosity of irradiated starch was stimulated by increasing pH. On the other hand, the solubility of irradiated starch increased significantly at the high pH. The granule structure of irradiated starch easily disintegrated at alkaline pH. Remarkable dissolution from the surface of the irradiated starch granules was observed after heating at high pH only a filamentous network frame remained, but the unirradiated one collapsed and folded. It was seen that alkali treatment after irradiation reduces the required dose to obtain low viscosity starch. The required dose to produce a low viscosity starch, for example Ajinomoto Essan Sizer 600 grade, was ca. 3 Mrad at pH 11.0 and ca. 5 Mrad at pH 7.0, whereas it was ca. 7 Mrad without pH adjustment. (author)

  20. Expression of multidrug resistance gene and P-glycoprotein in nasopharyngealcarcinoma cells after irradiation

    International Nuclear Information System (INIS)

    Wang Ruoyu; Wang Hui; Fan Kai; Lv Shen

    2007-01-01

    Objective: To mimick a clinical fractionated protocol of exposure to X-radiation in vitro in order to investigate the changes in the function of MDR1 and P-gp in nasopharyngeal carcinoma (NPC) CNE cell before and after irradiation to determine the sequential order of radiotherapy and chemotherapy or the time of chemotherapy after radiotherapy in the treatment of NPC. Methods: Exponentially growing CNE cells were treated with fractionated X-radiation with total dose of 10 Gy (2 Gy per day for 5 days consecutively) in vitro. The expression of MDR1 gene was examined in CNE cells before irradiation and on days 4,8,13,17 and 21 after irradiation by RT-PCR, and its protein P-gp were detected by immunocytochemistry. The function of multidrug resistance protein P-gp was examined by MTT method. Results: Expression of MDR1 gene was below the level of detection before irradiation. Irradiation induced an overexpression of MDR1 gene on day 4, expression of MDR1 was decreased from day 8 to day 21. The overall expression of MDR1 was significantly more than that before irradiation (P<0.05) Expression of P-gp was below the level of detection before irradiation, which demonstrated that irradiation induced an overexpression of P-gp. This overexpression was increased from day 8 to day 21. The overpression of MDR1 gene was maintained dining a short period, however, the emergence of overpression of protein P-gp was later than that of MDR1 gene. Resistance index was 1 for both pre-irradiation and on day 8, and up to 8,10,11.2 on days 13, 17 and 21, respectively. The change of resistance index was accordant with the condition of overexpression of P-gp . Conclusions: Expression of P-gp in nasopharyngeal carcinoma (NPC) CNE cell was below the level of detection before irradiation. Irradiation can induce an overexpression of MDR1 gene and its protein P-gp in CNE cells. The overexpression of MDR1 gene and its protein P-gp lasted a long term. (authors)

  1. Effect of a magnetic field on the fluorescence produced in irradiated anthracene solutions

    International Nuclear Information System (INIS)

    Dixon, R.S.; Sargent, F.P.; Lopata, V.J.; Gardy, E.M.; Brocklehurst, B.

    1977-01-01

    The effect of an applied magnetic field on the fluorescence from radiolytic ion recombination has been studied for anthracene in some hydrocarbon solvents. In pulse-irradiated anthracene in squalane, the fluorescence intensity following the pulse increases as a function of applied magnetic field in the range studied. At a constant magnetic field strength, the field-induced enhancement of the fluorescence intensity varies with time after the pulse. At high field strengths the enhancement reaches a maximum about 50 ns after the pulse. Similar effects are observed in cyclohexane but the enhancement is smaller than that in squalane. In benzene solutions the effect is extremely small. These findings are confirmed by observations in continuously gamma-irradiated solutions. 9,10-Dimethylanthracene gives a larger enhancement and anthracene-d 10 a smaller enhancement than the parent anthracene at high fields. The results are in general agreement with recent theoretical predictions based on the effect of a magnetic field on the loss of spin correlation of geminate ions pairs prior to recombination

  2. Large Magnetic Anisotropy in HfMnP

    Science.gov (United States)

    Parker, David; Lamichhane, Tej; Taufour, Valentin; Masters, Morgan; Thimmaiah, Srinivasa; Bud'Ko, Ser'gey; Canfield, Paul

    We present a theoretical and experimental study of two little-studied manganese phosphide ferromagnets, HfMnP and ZrMnP, with Curie temperatures above room temperature. We find an anisotropy field in HfMnP approaching 10 T - larger than that of the permanent magnet workhorse NdFeB magnets. From theory we determine the source of this anisotropy. Our results show the potential of 3d-element-based magnetic materials for magnetic applications.

  3. Effects of Nd:YAG laser irradiation on structural, morphological, cation distribution and magnetic properties of nanocrystalline CoFe{sub 2}O{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Mane, Maheshkumar L., E-mail: mane.maheshkumar@hotmail.com [Department of Physics, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad (M.S.) 431004 (India); Dhage, Vinod N. [Department of Physics, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad (M.S.) 431004 (India); Sundar, R.; Ranganathan, K.; Oak, S.M. [Solid State Laser Division, Raja Ramanna Center for Advanced Technology, Indore (M.P.) (India); Shengule, D.R.; Jadhav, K.M. [Department of Physics, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad (M.S.) 431004 (India)

    2011-08-01

    The cobalt ferrite nanoparticles of 20 nm size were synthesized by sol-gel auto-combustion technique. The samples were irradiated with Nd:YAG laser to understand the effects of irradiation on structural, cation distribution and magnetic properties. The virgin and irradiated samples were characterized by X-ray diffraction technique. The X-ray diffraction studies at room temperature shows that defects were created in the lattice after irradiation which causes effects on structural, cation distribution and magnetic properties. The energy dispersive analysis of X-rays (EDAX) showed the chemical composition is as per the expected stichiometry. The lattice constant observed from XRD data for virgin and irradiated samples shows increasing trend after irradiation. Cation distribution was investigated by using X-ray diffraction method. We observe decrease in magnetization of the samples after irradiation. The observed reduction in the saturation magnetization after irradiation can be understood on the basis of the partial formation of paramagnetic centers and rearrangement of cations in the lattice.

  4. Comparison of UVB and UVC irradiation disinfection efficacies on Pseudomonas Aeruginosa (P. aeruginosa) biofilm

    Science.gov (United States)

    Argyraki, A.; Markvart, M.; Nielsen, Anne; Bjarnsholt, T.; Bjørndal, L.; Petersen, P. M.

    2016-04-01

    Disinfection routines are important in all clinical applications. The uprising problem of antibiotic resistance has driven major research efforts towards alternative disinfection approaches, involving light-based solutions. Pseudomonas aeruginosa (P. aeruginosa) is a common bacterium that can cause skin, soft tissue, lungs, kidney and urinary tract infections. Moreover, it can be found on and in medical equipment causing often cross infections in hospitals. The objective of this study was to test the efficiency, of two different light-based disinfection treatments, namely UVB and UVC irradiation, on P. aeruginosa biofilms at different growth stages. In our experiments a new type of UV light emitting diodes (LEDs) were used to deliver UV irradiation on the biofilms, in the UVB (296nm) and UVC (266nm) region. The killing rate was studied as a function of dose for 24h grown biofilms. The dose was ramped from 72J/m2 to 10000J/m2. It was shown that UVB irradiation was more effective than UVC irradiation in inactivating P. aeruginosa biofilms. No colony forming units (CFU) were observed for the UVB treated biofilms when the dose was 10000 J/m2 (CFU in control sample: 7.5 x 104). UVB irradiation at a dose of 20000J/m2 on mature biofilms (72h grown) resulted in a 3.9 log killing efficacy. The fact that the wavelength of 296nm exists in daylight and has such disinfection ability on biofilms gives new perspectives for applications within disinfection at hospitals.

  5. Bulk and interface defects in electron irradiated InP

    International Nuclear Information System (INIS)

    Peng Chen; Sun Heng-hui

    1989-01-01

    Systematic studies on the structure of defects in InP caused by electron irradiation are conducted based on experimental measurements and theoretical calculations. The rates of introduction and annealing-out temperatures of In and P vancancies are estimated using proper theoretical models. These calculations reveal that after room temperature irradiation only complexes may exist. It is also supported by our experimental data that the sum of introducing rates of three detected levels are less than the theoretical value calculated for single vacancies. According to our equation on the relation between interface states and DLTS signal and from the results of computer calculation we believe that the broad peak appearing in the DLTS diagram before irradiation is related to interface states. Its disappearance after electron irradiation suggests the reduction of interface states; this is further confirmed by the reduction of surface recombination rate derived from the results of surface photovoltage measurement

  6. Influence of neutron irradiation on the magnetic properties of the Fe Ni pure alloy and with impurities of Si and Mo

    International Nuclear Information System (INIS)

    Lucki, George

    1971-01-01

    Hysteresis loop, Initial permeability and Curie Temperature measurements were conducted on several pure and polluted (with Si and Mo) Fe Ni 50-50% at. alloys. Isochronal annealings were performed between 25 deg 65 deg C, on each composition in three different ways: quenched (anisotropic) samples; quenched and irradiated samples; quenched irradiated samples annealed with saturating magnetic field. The experiment showed a sharp decrease in all parameters of the polluted alloys. Fast neutron irradiation results indicated that the magnetic properties are affected by the defects created during irradiation. The effect of thermal treatment, magnetic annealing and irradiation is greatest in anisotropic alloys. It is considered that magnetic annealing introduces a uniaxial anisotropy that tends to increase the remanence and hence the squareness of the hysteresis loop; but an increase in both remanence and coercivity was measured even in absence of the magnetic field. Magnetic after effect has been detected and a simple model for the diffusion of defects is presented. Many models have been proposed to explain the resultant properties, the most feasible being that based upon short-range ordering, proposed by Neel and Taniguchi, together with the interesting hypothesis of Heidenreich and Nesbitt. (author)

  7. Defects in low temperature electron irradiated InP

    International Nuclear Information System (INIS)

    Suski, J.; Bourgoin, J.

    1984-01-01

    n and p-InP has been irradiated at 25K with 1MeV electrons and the created defects were studied by deep level transient spectroscopy (DLTS) in the range 25K-400K. In n-InP, four traps are directly observed, with low introduction rates except for one. They anneal in three stages, and four new centers of still lower concentration appear after 70 0 C heat treatment. In p-InP, two dominant traps stable up to approx.= 400K with introduction rates close to the theoretical ones, which might be primary defects are found, while another one is clearly a secondary defect likely associated to Zn dopant. At least two of the low concentration irradiation induced electron traps, created between 25K and 100K are also secondary defects, which implies a mobility of some primary defects down to 100K at least. (author)

  8. Effect of low temperature reactor irradiation on organic insulators in superconducting magnets, (4)

    International Nuclear Information System (INIS)

    Kato, Teruo; Takamura, Saburo

    1983-01-01

    In order to study effects of irradiation at low temperature on insulating materials of superconducting magnets, flexural and impact tests are carried out at 4.2K without warmup after low temperature irradiation for several fiber reinforced plastics. The used materials are glass fiber reinforced epoxies and polyimide, and carbon fiber reinforced epoxies. After irradiation of 1.1 X 10 9 rad, the reduction in flexural strength of G-10 CR is about 70% and that of G-11 CR about 25%. No change are observed in strength of glass fiber reinforced polyimide by low temperature irradiation. Other kinds of glass fiber reinforced epoxies show a reduction in strength but the flexural strength of carbon fiber reinforced epoxies increases a small by irradiation. Irradiation effect of these materials on impact value is similar to that on flexural strength. (author)

  9. Development of irradiation rig in HTTR and dosimetry method. I-I type irradiation equipment

    Energy Technology Data Exchange (ETDEWEB)

    Shibata, Taiju; Kikuchi, Takayuki [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Miyamoto, Satoshi; Ogura, Kazutomo [Japan Atomic Power Co., Tokyo (Japan)

    2002-12-01

    The High Temperature Engineering Test Reactor (HTTR) is a graphite-moderated, helium gas-cooled test reactor with a maximum power of 30 MW. The HTTR aims not only to establish and upgrade the technological basis for the HTGRs but also to perform the innovative basic research on high temperature engineering with high temperature irradiation fields. It is planned that the HTTR is used to perform various engineering tests such as the safety demonstration test, high temperature test operation and irradiation test with large irradiation fields at high temperatures. This paper describes the design of the I-I type irradiation equipment developed as the first irradiation rig for the HTTR and does the planned dosimetry method at the first irradiation test. It was developed to perform in-pile creep test on a stainless steel with large standard size specimens in the HTTR. It can give great loads on the specimens stably and can control the irradiation temperature precisely. The in-core creep properties on the specimens are measured by newly developed differential transformers and the irradiation condition in the core is monitored by thermocouples and self-powered neutron detectors (SPNDs), continuously. The irradiated neutron fluence is assessed by neutron fluence monitors of small metallic wires after the irradiation. The obtained data at the first irradiation test can strongly be contributed to upgrade the technological basis for the HTGRs, since it is the first direct measurement of the in-core irradiation environments of the HTTR. (author)

  10. Controlling magnetic domain wall motion in the creep regime in He+-irradiated CoFeB/MgO films with perpendicular anisotropy

    International Nuclear Information System (INIS)

    Herrera Diez, L.; García-Sánchez, F.; Adam, J.-P.; Devolder, T.; Eimer, S.; El Hadri, M. S.; Ravelosona, D.; Lamperti, A.; Mantovan, R.; Ocker, B.

    2015-01-01

    This study presents the effective tuning of perpendicular magnetic anisotropy in CoFeB/MgO thin films by He + ion irradiation and its effect on domain wall motion in a low field regime. Magnetic anisotropy and saturation magnetisation are found to decrease as a function of the irradiation dose which can be related to the observed irradiation-induced changes in stoichiometry at the CoFeB/MgO interface. These changes in the magnetic intrinsic properties of the film are reflected in the domain wall dynamics at low magnetic fields (H) where irradiation is found to induce a significant decrease in domain wall velocity (v). For all irradiation doses, domain wall velocities at low fields are well described by a creep law, where Ln(v) vs. H −1∕4 behaves linearly, up to a maximum field H*, which has been considered as an approximation to the value of the depinning field H dep . In turn, H* ≈ H dep is seen to increase as a function of the irradiation dose, indicating an irradiation-induced extension of the creep regime of domain wall motion

  11. Angular and magnetic field dependences of critical current in irradiated YBaCuO single crystals

    International Nuclear Information System (INIS)

    Petrusenko, Yu.

    2010-01-01

    The investigation of mechanisms responsible for the current-carrying capability of irradiated high-temperature superconductors (HTSC) was realized. For the purpose, experiments were made to investigate the effect of point defects generated by high-energy electron irradiation on the critical temperature and the critical current in high-Tc superconducting single crystals YBa 2 Cu 3 O 7-x . The transport current density measured in HTSC single crystals YBa 2 Cu 3 O 7-x by the dc-method was found to exceed 80000 A/cm 2 . The experiments have demonstrated a more than 30-fold increase in the critical current density in single crystals irradiated with 2.5 MeV electrons to a dose of 3·10 18 el/cm 2 . Detailed studies were made into the anisotropy of critical current and the dependence of critical current on the external magnetic field strength in irradiated single crystals. A high efficiency of point defects as centers of magnetic vortex pinning in HTSC single crystals was first demonstrated.

  12. Air-electron stream interactions during magnetic resonance IGRT. Skin irradiation outside the treatment field during accelerated partial breast irradiation

    International Nuclear Information System (INIS)

    Park, Jong Min; Shin, Kyung Hwan; Wu, Hong-Gyun; Kim, Jung-in; Park, So-Yeon; Kim, Jin Ho; Jeon, Seung Hyuck; Choi, Noorie

    2018-01-01

    To investigate and to prevent irradiation outside the treatment field caused by an electron stream in the air generated by the magnetic field during magnetic resonance image-guided accelerated partial breast irradiation (APBI). In all, 20 patients who received APBI with a magnetic resonance image-guided radiation therapy (MR-IGRT) system were prospectively studied. The prescription dose was 38.5 Gy in 10 fractions of 3.85 Gy and delivered with a tri-cobalt system (the ViewRay system). For each patient, primary plans were delivered for the first five fractions and modified plans with different gantry angles from those of the primary plan (in-treatment plans) were delivered for the remaining five fractions to reduce the skin dose. A 1 cm thick bolus was placed in front of the patient's jaw, ipsilateral shoulder, and arm to shield them from the electron stream. Radiochromic EBT3 films were attached to the front (towards the breast) and back (towards the head) of the bolus during treatment. Correlations between the measured values and the tumor locations, treatment times, and tumor sizes were investigated. For a single fraction delivery, the average areas of the measured isodoses of 14% (0.54 Gy), 12% (0.46 Gy), and 10% (0.39 Gy) at the front of the boluses were as large as 3, 10.4, and 21.4 cm 2 , respectively, whereas no significant dose could be measured at the back of the boluses. Statistically significant but weak correlations were observed between the measured values and the treatment times. During radiotherapy for breast cancer with an MR-IGRT system, the patient must be shielded from electron streams in the air generated by the interaction of the magnetic field with the beams of the three-cobalt treatment unit to avoid unwanted irradiation of the skin outside the treatment field. (orig.) [de

  13. p53-independent early and late apoptosis is mediated by ceramide after exposure of tumor cells to photon or carbon ion irradiation

    International Nuclear Information System (INIS)

    Alphonse, Gersende; Maalouf, Mira; Battiston-Montagne, Priscillia; Ardail, Dominique; Beuve, Michaël; Rousson, Robert; Taucher-Scholz, Gisela; Fournier, Claudia; Rodriguez-Lafrasse, Claire

    2013-01-01

    To determine whether ceramide is responsible for the induction of p53-independent early or late apoptosis in response to high- and low-Linear-Energy-Transfer (LET) irradiation. Four cell lines displaying different radiosensitivities and p53-protein status were irradiated with photons or 33.4 or 184 keV/μm carbon ions. The kinetics of ceramide production was quantified by fluorescent microscopy or High-Performance-Liquid-Chromatogaphy and the sequence of events leading to apoptosis by flow cytometry. Regardless of the p53-status, both low and high-LET irradiation induced an early ceramide production in radiosensitive cells and late in the radioresistant. This production strongly correlated with the level of early apoptosis in radiosensitive cells and delayed apoptosis in the radioresistant ones, regardless of radiation quality, tumor type, radiosensitivity, or p53-status. Inhibition of caspase activity or ceramide production showed that, for both types of radiation, ceramide is essential for the initiation of early apoptosis in radiosensitive cells and late apoptosis following mitotic catastrophe in radioresistant cells. Ceramide is a determining factor in the onset of early and late apoptosis after low and high-LET irradiation and is the mediator of the p53-independent-apoptotic pathway. We propose that ceramide is the molecular bridge between mitotic catastrophe and the commitment phase of delayed apoptosis in response to irradiation

  14. Irradiation-induced softening of Ni3P and (Ni, Fe, Cr)3P alloys

    International Nuclear Information System (INIS)

    Schumacher, G.; Miekeley, W.; Wahi, R.P.

    1993-01-01

    Production of amorphous alloys by solid state reactions (SSR) has attracted much interest during the last few years. One of the methods to induce such a reaction is the irradiation of suitable crystalline alloys by fast particles. Examination of this kind of SSR in M 3 P type of brazing alloys (M: Metal) is attractive because of the following reason: In brazed joints of candidate structural materials like 316L stainless steel for applications in fusion reactors, crystalline intermetallic phases have been detected which are unstable relative to the amorphous state when irradiated at moderate temperatures with fast particles. It is expected that the transition to the amorphous state is accompanied by changes of the mechanical properties, which are of fundamental interest in this context. Until now, only a few studies on the evolution of mechanical properties during amorphization have been performed. Measurements of microhardness of the crystalline and the corresponding amorphous phase do not exist to the authors knowledge. In this communication, the authors present results on changes of microhardness, due to amorphization by fast ions. The measurements have been performed on a model alloy Ni 3 P and on the brazed joint of stainless steel 316L, containing M 3 P (M: Ni, Fe, Cr) as one of the phases. Though microhardness is not a fundamental property of materials, it is a manifestation of several related properties, such as yield stress, ductility, work-hardening, elastic modulus and residual stress states. It represents a resistance for indentation and is, therefore, appropriate for comparative purposes

  15. optical properties and morphological structure of Eb-Irradiated LDPE / P P Blends

    International Nuclear Information System (INIS)

    Ali, Z.I.; Said, H.M.; Youssef, H.A.; Saleh, H.H.; Abdel Monem, N.M.

    2004-01-01

    Blending is an effective method for improving the physical and chemical properties of homopolymers. however, the problem of phase separation often in some polymer blends occurs due to incompatibility of homopolymer which impairs the expected physico- chemical properties of blends. in this study , isotactic polypropylene, (P P), was blended with low density polyethylene, (LDPE), in the presence of various ratios of polyfunctional monomer, (PFM), namely trimethylol propane trimethacrylate, (TMPTMA), as a crosslinking and/or compatibilizing agents. the electron beam irradiation of the investigated LDPE/PP blends was carried out at different irradiation doses up to 50 kGy to improve the compatibility of LDPE/PP blends. the dye affinity of disperse and basic dyes in LDPE, PP and LDPE/PP blends was investigated in terms of color strength and visible absorbance intensities. in addition, the microstructures of the investigated samples have been studied and it is considered as an indication of the compatibility of LDPE/PP blend. the results show that the unmodified and modified LDPE samples exhibit the highest values of both color strength and visible absorbance intensities compared with unmodified and modified PP samples. also the intensities of these values in the LDPE/PP blends decrease as the PP content increases in the blend . in addition, the increase of EB irradiation dose and PFM ratios leads to an increase in the values of color strength and visible absorbance intensities. moreover, the affinity of all investigated samples towards disperse dye is being more pronounced than the basic dye. the interfacial adhesion of LDPE/PP blend could be enhanced by adding crosslinking agent, (TMPTMA), and EB irradiation process with different irradiation doses. the obtained data for the microstructures of all the investigated samples support that the EB irradiation beside the incorporation of PEM into the homopolymer matrix remarkably improve the compatibility of the polymer blend

  16. Gene expression and apoptosis induction in p53-heterozygous irradiated mice

    International Nuclear Information System (INIS)

    Di Masi, Alessandra; Antoccia, Antonio; Dimauro, Ivan; Argentino-Storino, Alberta; Mosiello, Alberto; Mango, Ruggiero; Novelli, Giuseppe; Tanzarella, Caterina

    2006-01-01

    The role of the p53-genetic background in the expression of genes involved in either cell cycle checkpoint activation or apoptosis was evaluated in p53+/+ and p53+/- mouse strains at both basal levels and after DNA-induced damage. The spleen, colon, kidneys, lungs and liver of both strains were harvested from untreated animals and from mice exposed to 7.5 Gy of X-rays and sacrificed after 5 h. No significant differences were observed in the basal levels of p53 protein, CDKN1A and bax mRNA and spontaneous apoptosis, neither among the different organs within the same strain, nor between the same organ in the p53+/+ and p53+/- strains. After X-ray exposure, p53-dependent regulation was strikingly tissue-specific. In wild-type irradiated mice, p53 protein level increased after radiation treatment in all the organs analysed, whereas both CDKN1A and bax genes transcription increased in the spleen, colon and lungs, as assessed by means of quantitative RT-PCR. In p53+/- irradiated mice, on the contrary, a significant p53 induction was detected only in the spleen, while CDKN1A and bax genes levels increased in the spleen, colon and lungs, revealing the existence of different mechanisms of gene regulation in different organs. Apoptosis induction was observed in the spleen and colon of both strains, even if to lower extent in p53+/- mice compared to p53+/+ animals. In conclusion, in the spleen and colon, target gene transcription and apoptosis may be related to p53 genotype after DNA damage-induction. Moreover, our findings highlight the selectivity of p53 in transactivation following DNA damage in vivo, resulting in tissue-specific responses

  17. Gene expression and apoptosis induction in p53-heterozygous irradiated mice

    Energy Technology Data Exchange (ETDEWEB)

    Di Masi, Alessandra [Department of Biology, University of Rome ' Roma Tre' , Viale G. Marconi, 446, 00146 Rome (Italy); Antoccia, Antonio [Department of Biology, University of Rome ' Roma Tre' , Viale G. Marconi, 446, 00146 Rome (Italy); Dimauro, Ivan [Department of Biology, University of Rome ' Roma Tre' , Viale G. Marconi, 446, 00146 Rome (Italy); Argentino-Storino, Alberta [Research Toxicology Centre S.p.A., Via Tito Speri, 18, 00040 Pomezia (RM) (Italy); Mosiello, Alberto [Research Toxicology Centre S.p.A., Via Tito Speri, 18, 00040 Pomezia (RM) (Italy); Mango, Ruggiero [Centre of Excellence for Genomic Risk Assessment in Multifactorial and Complex Diseases, School of Medicine, University of Rome ' Tor Vergata' , Rome (Italy); Novelli, Giuseppe [Centre of Excellence for Genomic Risk Assessment in Multifactorial and Complex Diseases, School of Medicine, University of Rome ' Tor Vergata' , Rome (Italy); Tanzarella, Caterina [Department of Biology, University of Rome ' Roma Tre' , Viale G. Marconi, 446, 00146 Rome (Italy)]. E-mail: tanzarel@uniroma3.it

    2006-02-22

    The role of the p53-genetic background in the expression of genes involved in either cell cycle checkpoint activation or apoptosis was evaluated in p53+/+ and p53+/- mouse strains at both basal levels and after DNA-induced damage. The spleen, colon, kidneys, lungs and liver of both strains were harvested from untreated animals and from mice exposed to 7.5 Gy of X-rays and sacrificed after 5 h. No significant differences were observed in the basal levels of p53 protein, CDKN1A and bax mRNA and spontaneous apoptosis, neither among the different organs within the same strain, nor between the same organ in the p53+/+ and p53+/- strains. After X-ray exposure, p53-dependent regulation was strikingly tissue-specific. In wild-type irradiated mice, p53 protein level increased after radiation treatment in all the organs analysed, whereas both CDKN1A and bax genes transcription increased in the spleen, colon and lungs, as assessed by means of quantitative RT-PCR. In p53+/- irradiated mice, on the contrary, a significant p53 induction was detected only in the spleen, while CDKN1A and bax genes levels increased in the spleen, colon and lungs, revealing the existence of different mechanisms of gene regulation in different organs. Apoptosis induction was observed in the spleen and colon of both strains, even if to lower extent in p53+/- mice compared to p53+/+ animals. In conclusion, in the spleen and colon, target gene transcription and apoptosis may be related to p53 genotype after DNA damage-induction. Moreover, our findings highlight the selectivity of p53 in transactivation following DNA damage in vivo, resulting in tissue-specific responses.

  18. Apparatus for electron beam irradiation of objects

    International Nuclear Information System (INIS)

    Dmitriev, S.P.; Ivanov, A.S.; Sviniin, M.P.; Fedotov, M.T.

    1984-01-01

    This patent provides an apparatus for electron beam irradiation of objects, comprising a shaper of a ribbon-shaped electron beam and a deflecting electromagnet having a frame-type magnetic circuit and used to direct said electron beam onto an irradiated object substantially at an angle of 90 degrees. The deflecting electromagnet has two poles extended over the width of the irradiated object and comprises two windings embracing said poles and connected to a d.c. source. The deflecting electromagnet is arranged in such a manner that the trajectories of the electrons at an area from the shaper to the electromagnet are inclined to the plane of the frame of its magnetic circuit

  19. A review of radiation-induced demagnetization of permanent magnets

    Science.gov (United States)

    Samin, Adib J.

    2018-05-01

    Radiation-induced demagnetization of permanent magnets is important for a number of applications including space missions, particle accelerators and robots designed to carry out rescue missions at nuclear accidents where magnet failure can lead to serious consequences. This topic has been studied by several investigators over the past three decades and in this work, a review of the available literature is conducted and some general conclusions and trends are presented. In short, it can be gleaned that magnetism loss is dependent on the type of radiation, the energy of the incoming particle and the overall dose or fluence. Furthermore, magnetism loss also shows a dependence on the type of the irradiated magnet, the coercivity of the magnet, the demagnetizing field and the temperature of irradiation.

  20. Simulation of new p-type strip detectors with trench to enhance the charge multiplication effect in the n-type electrodes

    International Nuclear Information System (INIS)

    Fernández-Martínez, P.; Pellegrini, G.; Balbuena, J.P.; Quirion, D.; Hidalgo, S.; Flores, D.; Lozano, M.; Casse, G.

    2011-01-01

    This paper shows the simulation results of new p-type strip detectors with trench electrodes to enhance the charge multiplication effect in the irradiated detector. The new design includes baby microstrip detectors (area=1 cm 2 ) with a strip pitch of 80 μm and p-stop isolation structures. The strip has a 5 μm-wide trench along all its length, filled and doped with polysilicon to create a deep N + contact into the material bulk. The trench depth can be varied in order to study the influence of the electric field on the charge multiplication effect in heavily irradiated samples. Some alternative designs have also been studied to establish a comparison between various structures using different technologies. Simulation reproduce the electrical behaviour under different irradiation conditions, taking into account the damage accumulated after irradiation with neutrons and protons with several fluence values. The investigation of these effects provides important indications on the ability of this modified electrode geometry to control and optimise the charge multiplication effect, in order to fully recover the collection efficiency of heavily irradiated microstrip detectors, at reasonable bias voltage compatible with the voltage feed limitation of the CERN SLHC experiments.

  1. Comparison of /sup 32/P therapy and sequential hemibody irradiation (HBI) for bony metastases as methods of whole body irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Aziz, H.; Choi, K.; Sohn, C.; Yaes, R.; Rotman, M.

    1986-06-01

    We report a retrospective study of 15 patients with prostate carcinoma and diffuse bone metastases treated with sodium /sup 32/P for palliation of pain at Downstate Medical Center and Kings County Hospital from 1973 to 1978. The response rates, duration of response, and toxicities are compared with those of other series of patients treated with /sup 32/P and with sequential hemibody irradiation. The response rates and duration of response are similar with both modalities ranging from 58 to 95% with a duration of 3.3 to 6 months with /sup 32/P and from 75 to 86% with a median duration of 5.5 months with hemibody irradiation. There are significant differences in the patterns of response and in the toxicities of the two treatment methods. Both methods cause significant bone marrow depression. Acute radiation syndrome, radiation pneumonitis, and alopecia are seen with sequential hemibody irradiation and not with /sup 32/P, but their incidence can be reduced by careful treatment planning. Hemibody irradiation can provide pain relief within 24 to 48 h, while /sup 32/P may produce an initial exacerbation of pain. Lower hemibody irradiation alone is less toxic than either upper hemibody irradiation or /sup 32/P treatment.

  2. Effect of gamma irradiation on the chemical compositions of some feed block types

    International Nuclear Information System (INIS)

    Al-Masri, M.R.

    1994-02-01

    The effect of gamma irradiation (100 kilo gray,KGy) on chemical compositions for 3 types of feed blocks was studied. the first type (Type I) contained 28% wheat bran, 31% dried poultry manure, 20% molasses, 10% urea, 6% Co(OH)-2, 5% salt. Type (II) contained 22% wheat bran, 10% dried poultry manure, 30% dried beet pule, 20% molasses, 8% urea, 6% Ca(OH)-2, 4% salt. Type (III) contained 35% olive cake, 30% wheat bran, 10% urea, 15% cement, 10% salt. The results indicate that there were significant differences (P<0.05) between controls and treatments for the crude fibre (CF) and NDF. CF values decreased by 12% for all types. NDF values decreased by 25%, 19% and 16% and hemicellulose (HCL) by 46%, 35%, 44% for types (I), (II) and (III) respectively. Total nitrogen crude fat, crude ash, organic matter, ADF, ADL, cellulose (CL) and CL:ADL ratio did not change as a result of irradiation, CL:CF ratio increased by 14%, 10% and 17%, and CL:NDF ratio increased by 37%, 29% and 25% for types (I), (II) and (III) respectively. HCL:CF ratio decreased by 39%, 27% and 38% and HCL:NDF ratio by 27%, 20% and 33% and HCL:ADL ratio decreased by 45%, 30%, and 40% for types (I), (II), (III) respectively. (author). 27 refs., 4 figs., 3 tabs

  3. The development of p-type silicon detectors for the high radiation regions of the LHC

    International Nuclear Information System (INIS)

    Hanlon, M.D.L.

    1998-04-01

    This thesis describes the production and characterisation of silicon microstrip detectors and test structures on p-type substrates. An account is given of the production and full parameterisation of a p-type microstrip detector, incorporating the ATLAS-A geometry in a beam test. This detector is an AC coupled device incorporating a continuous p-stop isolation frame and polysilicon biasing and is typical of n-strip devices proposed for operation at the LHC. It was successfully read out using the FELix-128 analogue pipeline chip and a signal to noise (s/n) of 17±1 is reported, along with a spatial resolution of 14.6±0.2 μm. Diode test structures were fabricated on both high resistivity float zone material and on epitaxial material and subsequently irradiated with 24 GeV protons at the CERN PS up to a dose of (8.22±0.23) x 10 14 per cm 2 . An account of the measurement program is presented along with results on the changes in the effective doping concentration (N eff ) with irradiation and the changes in bulk current. Changes in the effective doping concentration and leakage current for high resistivity p-type material under irradiation were found to be similar to to that of n-type material. Values of α=(3.30±0.08) x 10 -17 A cm -1 for the leakage current parameter and g c =(1.20±0.05)x10 -2 cm -1 for the effective dopant introduction rate were found for this material. The epitaxial material did not perform better than the float zone material for the range of doses studied. Surprising results were obtained for highly irradiated p-type diodes illuminated on the ohmic side with an α-source, in that signals were observed well below the full depletion voltage. The processing that had been used to fabricate the test structures and the initial prototype that was studied in the test beam was based on the process used to fabricate devices on n-type material. Presented in this thesis are the modifications that were made to the process, which centred on the oxidation

  4. Effects of PTEN transfer on cell cycle progression and expression of P27kipl followed by X-ray irradiation

    International Nuclear Information System (INIS)

    Tian Mei; Wu Congmei; Liu Linlin; Piao Chunji; Li Xiuyi

    2007-01-01

    Objective: To investigate the effect of pEgr-hPTEN stable transfer combined with irradiation on the cell cycle progression and the expression of cell cycle kinase inhibitor P27 kipl protein of SHG-44 human glioma cells. Methods: pEgr-hPTEN vector containing the exogenous wild type PTEN gene was transfected into SHG-44 cells under mediation of lipofectamine in vitro, the positive cell clones were selected and amplified by using G418. Western blotting was used to measure the expression of PTEN protein. Transmission electron microscope was adopted to detect the cell ultrastructural changes and flow cytometry was adopted to analysis the changes of cell cycle progression and the expression of P27 kipl in SHG-44-sPTEN cells followed by different doses of X-ray irradiation. Results: Egr-1 promoter could be induced and activated by irradiation and then enhanced the expression of downstream PTEN gene within 5 Gy. The ultrastructure of SHG-44-sPTEN cells had many degenerative changes and many early apoptotic changes including the chromosome condensate around the nuclear envelope. pEgr-hPTEN stable transfer combined with X-ray irradiation could significantly induce G 1 arrest. The expression of P27 kipl proteins increased in SHG-44-sPTEN stable transfected cells. Conclusion: PTEN stable transfer combined with irradiation can significantly induce G 1 arrest. The molecular basis may be correlated with the enhanced expression of PTEN induced by irradiation and increased expression of cell cycle kinase inhibitor P27 kipl . (authors)

  5. Observation of magnetically anisotropic defects during stage I recovery in nickel after low-temperature electron irradiation

    International Nuclear Information System (INIS)

    Forsch, K.; Hemmerich, J.; Knoll, H.; Lucki, G.

    1974-01-01

    The measurement of defect-induced changes of magnetic anisotropy in a nickel single crystal after low-temperature electron irradiation was undertaken. A dynamic measuring method was used after reorienting a certain fraction of the radiation-induced defects in an external magnetic field of 5 kOe. In the temperature range of recovery stage I sub(C,D,E) (45 to 60 k) the crystallographic direction dependence of defect-induced anisotropy could be determined. The results show that in this temperature range the (100) split interstitial is mobile and able to reorient. The obtained data are further discussed with respect to existing information on magnetic after effect and resistivity annealing in electron-irradiated nickel

  6. Time-resolved magnetic field effects in exciplex systems under X-irradiation

    International Nuclear Information System (INIS)

    Anishchik, S.V.; Lavrik, N.L.

    1988-01-01

    The presence of exciplex systems after X-irradiation of pyrene and N,N-diethylaniline in methanol as well as the influence of the applied magnetic field on exciplex fluorescence was registered using a time-resolving method. The experimental results confirmed the hypothesis on exciplex emergence in the system under study. (author)

  7. Hydrogen interaction with radiation defects in p-type silicon

    CERN Document Server

    Feklisova, O V; Yakimov, E B; Weber, J

    2001-01-01

    Hydrogen interaction with radiation defects in p-type silicon has been investigated by deep-level non-stationary spectroscopy. Hydrogen is introduced into the high-energy electron-irradiated crystals under chemical etching in acid solutions at room temperature followed by the reverse-bias annealing at 380 K. It is observed that passivation of the irradiation-induced defects is accompanied by formation of novel electrically active defects with hydrogen-related profiles. Effect of hydrogen on the electrical activity of the C sub s C sub i complexes is shown for the first time. Based on the spatial distribution and passivation kinetics, possible nature of the novel complexes is analyzed. The radii for hydrogen capture by vacancies, K-centers, C sub s C sub i centers and the novel complexes are determined

  8. Irradiation effect of the insulating materials for fusion superconducting magnets at cryogenic temperature

    Science.gov (United States)

    Kobayashi, Koji; Akiyama, Yoko; Nishijima, Shigehiro

    2017-09-01

    In ITER, superconducting magnets should be used in such severe environment as high fluence of fast neutron, cryogenic temperature and large electromagnetic forces. Insulating material is one of the most sensitive component to radiation. So radiation resistance on mechanical properties at cryogenic temperature are required for insulating material. The purpose of this study is to evaluate irradiation effect of insulating material at cryogenic temperature by gamma-ray irradiation. Firstly, glass fiber reinforced plastic (GFRP) and hybrid composite were prepared. After irradiation at room temperature (RT) or liquid nitrogen temperature (LNT, 77 K), interlaminar shear strength (ILSS) and glass-transition temperature (Tg) measurement were conducted. It was shown that insulating materials irradiated at room temperature were much degraded than those at cryogenic temperature.

  9. Controlling magnetic domain wall motion in the creep regime in He{sup +}-irradiated CoFeB/MgO films with perpendicular anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Herrera Diez, L., E-mail: liza.herrera-diez@ief.u-psud.fr; García-Sánchez, F.; Adam, J.-P.; Devolder, T.; Eimer, S.; El Hadri, M. S.; Ravelosona, D. [Institut d' Electronique Fondamentale, Université Paris-Sud, UMR CNRS 8622, 91405 Orsay (France); Lamperti, A.; Mantovan, R. [Laboratorio MDM, IMM-CNR, Via C. Olivetti 2, 20864 Agrate (MB) (Italy); Ocker, B. [Singulus Technology AG, Hanauer Landstrasse 103, 63796 Kahl am Main (Germany)

    2015-07-20

    This study presents the effective tuning of perpendicular magnetic anisotropy in CoFeB/MgO thin films by He{sup +} ion irradiation and its effect on domain wall motion in a low field regime. Magnetic anisotropy and saturation magnetisation are found to decrease as a function of the irradiation dose which can be related to the observed irradiation-induced changes in stoichiometry at the CoFeB/MgO interface. These changes in the magnetic intrinsic properties of the film are reflected in the domain wall dynamics at low magnetic fields (H) where irradiation is found to induce a significant decrease in domain wall velocity (v). For all irradiation doses, domain wall velocities at low fields are well described by a creep law, where Ln(v) vs. H{sup −1∕4} behaves linearly, up to a maximum field H*, which has been considered as an approximation to the value of the depinning field H{sub dep}. In turn, H* ≈ H{sub dep} is seen to increase as a function of the irradiation dose, indicating an irradiation-induced extension of the creep regime of domain wall motion.

  10. Investigation of the effect of some irradiation parameters on the response of various types of dosimeters to electron irradiation

    International Nuclear Information System (INIS)

    Farah, K.; Kuntz, F.; Kadri, O.; Ghedira, L.

    2004-01-01

    Several undyed and dyed polymer films are commercially available for dosimetry in intense radiation fields, especially for radiation processing of food and sterilisation of medical devices. The effects of temperature during irradiation and post-irradiation stability, on the response of these dosimeters are of importance to operators of irradiation facilities. The present study investigates the effects of temperature during irradiation by 2.2 MeV electrons beam accelerator and post irradiation storage on the response of several types of dosimeter films. All dosimeters showed a significant effect of temperature during irradiation and post-irradiation storage

  11. Investigation of the effect of some irradiation parameters on the response of various types of dosimeters to electron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Farah, K. E-mail: k.farah@cnstn.rnrt.tn; Kuntz, F.; Kadri, O.; Ghedira, L

    2004-10-01

    Several undyed and dyed polymer films are commercially available for dosimetry in intense radiation fields, especially for radiation processing of food and sterilisation of medical devices. The effects of temperature during irradiation and post-irradiation stability, on the response of these dosimeters are of importance to operators of irradiation facilities. The present study investigates the effects of temperature during irradiation by 2.2 MeV electrons beam accelerator and post irradiation storage on the response of several types of dosimeter films. All dosimeters showed a significant effect of temperature during irradiation and post-irradiation storage.

  12. The post-irradiated examination of CANDU type fuel irradiated in the Institute for Nuclear Research TRIGA reactor

    International Nuclear Information System (INIS)

    Tuturici, I.L.; Parvan, M.; Dobrin, R.; Popov, M.; Radulescu, R.; Toma, V.

    1995-01-01

    This post-irradiation examination work has been done under the Research Contract No. 7756/RB, concluded between the International Atomic Energy Agency and the Institute for Nuclear Research. The paper contains a general description of the INR post-irradiation facility and methods and the relevant post-irradiation examination results obtained from an irradiated experimental CANDU type fuel element designed, manufactured and tested by INR in a power ramp test in the 100 kW Pressurised Water Irradiation Loop of the TRIGA 14 MW(th) Reactor. The irradiation experiment consisted in testing an assembly of six fuel elements, designed to reach a bumup of ∼ 200 MWh/kgU, with typical CANDU linear power and ramp rate. (author)

  13. Magnetism by interfacial hybridization and p-type doping of MoS(2) in Fe(4)N/MoS(2) superlattices: a first-principles study.

    Science.gov (United States)

    Feng, Nan; Mi, Wenbo; Cheng, Yingchun; Guo, Zaibing; Schwingenschlögl, Udo; Bai, Haili

    2014-03-26

    Magnetic and electronic properties of Fe4N(111)/MoS2(√3 × √3) superlattices are investigated by first-principles calculations, considering two models: (I) Fe(I)Fe(II)-S and (II) N-S interfaces, each with six stacking configurations. In model I, strong interfacial hybridization between Fe(I)/Fe(II) and S results in magnetism of monolayer MoS2, with a magnetic moment of 0.33 μB for Mo located on top of Fe(I). For model II, no magnetism is induced due to weak N-S interfacial bonding, and the semiconducting nature of monolayer MoS2 is preserved. Charge transfer between MoS2 and N results in p-type MoS2 with Schottky barrier heights of 0.5-0.6 eV. Our results demonstrate that the interfacial geometry and hybridization can be used to tune the magnetism and doping in Fe4N(111)/MoS2(√3 × √3) superlattices.

  14. Magnetization at high pressure in CeP

    Science.gov (United States)

    Naka, T.; Matsumoto, T.; Okayama, Y.; Môri, N.; Haga, Y.; Suzuki, T.

    1995-02-01

    We have investigated the pressure dependence of magnetization below 60 K up to 1.6 GPa in the low-carrier concentration system CeP showing two step transitions at T = TL and TH under high pressure. At high pressure, M( P, T) exhibits a maximum at around the lower transition temperature TL. This behavior implies that the magnetic state changes at TL. The pressure dependence of isothermal magnetization M( P) is different above and below TL. In fact, M( P) below TL exhibits a maximum at around 1.4 GPa, whereas M( P) above TL increases steeply with pressure up to 1.6 GPa.

  15. Effect of microwave irradiation on selective heating behavior and magnetic separation characteristics of Panzhihua ilmenite

    International Nuclear Information System (INIS)

    Zhao, Wei; Chen, Jin; Chang, Xiaodong; Guo, Shenghui; Srinivasakannan, C.; Chen, Guo; Peng, Jinhui

    2014-01-01

    Highlights: • Microwave irradiation can be applied effectively and efficiently to the irradiation processes of Panzhihua ilmenite. • The mineral processing properties of microwave treated ilmenite were generally as good as or better than that of initial ilmenite. • The microwave selective heating characteristics of the different minerals and compounds, and the thermal stresses were caused by the uniform heat rate disturbed under microwave irradiation. - Abstract: The influences of microwave irradiation on the surface characteristics of Panzhihua ilmenite were systematically investigated. The crystal structures, surface morphology and surface chemical functional groups of ilmenite were characterized before and after microwave irradiation and magnetic separation for different microwave treatment times by using various methods, such as XRD, SEM, and FT-IR, respectively. XRD analysis showed that the microwave treated ilmenite has the strongest peaks of phase more than that of raw samples, indicates that the crystalline compound of ilmenite increased with the microwave irradiation time. SEM analysis showed the micro-cracking appeared at many grain boundaries of ilmenite after being pretreated by microwave treatment. The separations of ilmenite from gangue minerals were completed and the micro-fissure within ilmenite minerals were also formed, which could be attributed to the microwave selective heating characteristics of the different minerals and compounds, and the thermal stresses were caused by the uniform heat rate disturbed under microwave irradiation. The mineral processing results showed that the magnetic separation characteristics and properties of microwave treated ilmenite samples were better than that of microwave untreated ilmenite samples. It was concluded that microwave irradiation can be applied effectively and efficiently to the irradiation processes of Panzhihua ilmenite

  16. Experimental and theoretical basis of agricultural plant immunostimulation with regard to pathogenic fungi by magnetic field and He-Ne laser irradiation

    Science.gov (United States)

    Belski, Alexey I.; Chivanov, Vadym D.

    1996-09-01

    Spring barley, winter wheat and maize seeds were subjected to the action of He-Ne laser irradiation having a low intensity in the visible region of the spectrum (628-640 nm) in conjunction with magnetic fields. The following results were obtained: laser irradiation with magnetic fields induced activation of the natural plant defence/immune systems gave the harvest crop level increased to about 50- 300 percent; a correlation was established between the rate of the fungal pathogens growth and the stimulation of plant immunity after the seeds had been treated with laser irradiation and magnetic field.

  17. The study of 1 MeV electron irradiation induced defects in N-type and P-type monocrystalline silicon

    Science.gov (United States)

    Babaee, S.; Ghozati, S. B.

    2017-12-01

    Despite extensive use of GaAs cells in space, silicon cells are still being used. The reason is that not only they provide a good compromise between efficiency and cost, but also some countries do not have the required technology for manufacturing GaAs. Behavior of a silicon cell under any levels of charged particle irradiation could be deducted from the results of a damage equivalent 1 MeV electron irradiation using the NASA EQflux open source software package. In this paper for the first time, we have studied the behavior of a silicon cell before and after 1 MeV electron irradiation with 1014, 1015 and 1016 electrons-cm-2 fluences, using SILVACO TCAD simulation software package. Simulation was carried out at room temperature under AM0 condition. Results reveal that open circuit voltage and efficiency decrease after irradiation while short circuit current shows a slight increase in the trend around 5 × 1016 electrons-cm-2, and short circuit current loss plays an important role on efficiency changes rather than open circuit voltage.

  18. Effects of Nd:YAG laser irradiation on structural and magnetic properties of Li{sub 0.5}Fe{sub 2.5}O{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Mane, Maheshkumar L. [Department of Physics, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad (M.S.) 431004 (India); Sundar, R.; Ranganathan, K.; Oak, S.M. [Solid State Laser Division, Raja Raman Research Center for Advanced Technology, Indore (M.P.) (India); Jadhav, K.M., E-mail: drkmjadhav@yahoo.co [Department of Physics, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad (M.S.) 431004 (India)

    2011-02-15

    In the present paper we report our results on the effect of Nd:YAG laser irradiation on the structural and magnetic properties of Li{sub 0.5}Fe{sub 2.5}O{sub 4} spinel ferrite prepared by solid-state reaction technique. X-ray diffraction analysis was carried out to confirm the formation of the single phase cubic spinel structure. The lattice constant calculated from X-ray diffraction data (XRD) goes on increasing with non irradiated phase to exceeding higher doses of irradiation. The distribution of the substituted ions over the different lattice sites is determined from XRD and infrared spectra. The damage structure and morphological investigations were carried out by using scanning electron microscopy and transmission electron microscopy techniques. It has been observed from our data on magnetic properties that laser irradiation severely affects the magnetization. From the magnetization measurements it has been observed that the saturation magnetization decreases with increase in the laser dose rate. The observed reduction in the saturation magnetization after irradiation is understood on the basis of the partial formation of paramagnetic centers and rearrangement of cations in the lattice.

  19. Air-electron stream interactions during magnetic resonance IGRT : Skin irradiation outside the treatment field during accelerated partial breast irradiation.

    Science.gov (United States)

    Park, Jong Min; Shin, Kyung Hwan; Kim, Jung-In; Park, So-Yeon; Jeon, Seung Hyuck; Choi, Noorie; Kim, Jin Ho; Wu, Hong-Gyun

    2018-01-01

    To investigate and to prevent irradiation outside the treatment field caused by an electron stream in the air generated by the magnetic field during magnetic resonance image-guided accelerated partial breast irradiation (APBI). In all, 20 patients who received APBI with a magnetic resonance image-guided radiation therapy (MR-IGRT) system were prospectively studied. The prescription dose was 38.5 Gy in 10 fractions of 3.85 Gy and delivered with a tri-cobalt system (the ViewRay system). For each patient, primary plans were delivered for the first five fractions and modified plans with different gantry angles from those of the primary plan (in-treatment plans) were delivered for the remaining five fractions to reduce the skin dose. A 1 cm thick bolus was placed in front of the patient's jaw, ipsilateral shoulder, and arm to shield them from the electron stream. Radiochromic EBT3 films were attached to the front (towards the breast) and back (towards the head) of the bolus during treatment. Correlations between the measured values and the tumor locations, treatment times, and tumor sizes were investigated. For a single fraction delivery, the average areas of the measured isodoses of 14% (0.54 Gy), 12% (0.46 Gy), and 10% (0.39 Gy) at the front of the boluses were as large as 3, 10.4, and 21.4 cm 2 , respectively, whereas no significant dose could be measured at the back of the boluses. Statistically significant but weak correlations were observed between the measured values and the treatment times. During radiotherapy for breast cancer with an MR-IGRT system, the patient must be shielded from electron streams in the air generated by the interaction of the magnetic field with the beams of the three-cobalt treatment unit to avoid unwanted irradiation of the skin outside the treatment field.

  20. Radiation damage and defect behavior in proton irradiated lithium-counterdoped n+p silicon solar cells

    Science.gov (United States)

    Stupica, John; Goradia, Chandra; Swartz, Clifford K.; Weinberg, Irving

    1987-01-01

    Two lithium-counterdoped n+p silicon solar cells with different lithium concentrations were irradiated by 10-MeV protons. Cell performance was measured as a function of fluence, and it was found that the cell with the highest concentration of lithium had the highest radiation resistance. Deep level transient spectroscopy which showed two deep level defects that were lithium related. Relating the defect energy levels obtained from this study with those from earlier work using 1-MeV electron irradiation shows no correlation of the defect energy levels. There is one marked similarity: the absence of the boron-interstitial-oxygen-interstitial defect. This consistency strengthens the belief that lithium interacts with oxygen to prevent the formation of the boron interstitial-oxygen interstitial defect. The results indicate that, in general, addition of lithium in small amounts to the p-base of a boron doped silicon solar cell such that the base remains p-type, tends to increase the radiation resistance of the cell.

  1. Acousto-defect interaction in irradiated and non-irradiated silicon n+-p structures

    Science.gov (United States)

    Olikh, O. Ya.; Gorb, A. M.; Chupryna, R. G.; Pristay-Fenenkov, O. V.

    2018-04-01

    The influence of ultrasound on current-voltage characteristics of non-irradiated silicon n+-p structures as well as silicon structures exposed to reactor neutrons or 60Co gamma radiation has been investigated experimentally. It has been found that the ultrasound loading of the n+-p structure leads to the reversible change of shunt resistance, carrier lifetime, and ideality factor. Specifically, considerable acoustically induced alteration of the ideality factor and the space charge region lifetime was observed in the irradiated samples. The experimental results were described by using the models of coupled defect level recombination, Shockley-Read-Hall recombination, and dislocation-induced impedance. The experimentally observed phenomena are associated with the increase in the distance between coupled defects as well as the extension of the carrier capture coefficient of complex point defects and dislocations. It has been shown that divacancies and vacancy-interstitial oxygen pairs are effectively modified by ultrasound in contrast to interstitial carbon-interstitial oxygen complexes.

  2. Commissioning dosimetry for the laboratory irradiation facility type PX-γ-30

    International Nuclear Information System (INIS)

    Prieto Miranda, E.F.; Cuesta Fuente, G.I.; Chavez Ardanza, A.; Sainz Vidal, D.

    1997-01-01

    In the present paper at the laboratory irradiation type PX-y-30 was carried out the commissioning dosimetry, which belongs to Radiological Department of the CEADEN. It was determined the dose distribution as well as principal dosimetric parameters of the irradiation process. Besides, an irradiation position was found for the calibration or intercomparison of dosimetry systems

  3. Synthesis of flexible magnetic nanohybrid based on bacterial cellulose under ultrasonic irradiation

    International Nuclear Information System (INIS)

    Zheng, Yi; Yang, Jingxuan; Zheng, Weili; Wang, Xiao; Xiang, Cao; Tang, Lian; Zhang, Wen; Chen, Shiyan; Wang, Huaping

    2013-01-01

    Flexible magnetic membrane based on bacterial cellulose (BC) was successfully prepared by in-situ synthesis of the Fe 3 O 4 nanoparticles under different conditions and its properties were characterized. The results demonstrated that the Fe 3 O 4 nanoparticles coated with PEG were well homogeneously dispersed in the BC matrix under ultrasonic irradiation with the saturation magnetization of 40.58 emu/g. Besides that, the membranes exhibited the striking flexibility and mechanical properties. This study provided a green and facile method to inhibit magnetic nanoparticle aggregation without compromising the mechanical properties of the nanocomposites. Magnetically responsive BC membrane would have potential applications in electronic actuators, information storage, electromagnetic shielding coating and anti-counterfeit. - Highlights: ► Flexible magnetic film is prepared by in situ synthesis on bacterial cellulose. ► Ultrasound and PEG are used together to inhibit the nanoparticle aggregation. ► The magnetic membrane demonstrates the great superparamagnetic behavior

  4. Germanium-doped gallium phosphide obtained by neutron irradiation

    Science.gov (United States)

    Goldys, E. M.; Barczynska, J.; Godlewski, M.; Sienkiewicz, A.; Heijmink Liesert, B. J.

    1993-08-01

    Results of electrical, optical, electron spin resonance and optically detected magnetic resonance studies of thermal neutron irradiated and annealed at 800 °C n-type GaP are presented. Evidence is found to support the view that the main dopant introduced via transmutation of GaP, germanium, occupies cation sites and forms neutral donors. This confirms the possibility of neutron transmutation doping of GaP. Simultaneously, it is shown that germanium is absent at cation sites. Presence of other forms of Ge-related defects is deduced from luminescence and absorption data. Some of them are tentatively identified as VGa-GeGa acceptors leading to the self-compensation process. This observation means that the neutron transmutation as a doping method in application to GaP is not as efficient as for Si.

  5. The investigation of the magnetic after-effect in iron-alpha after neutron irradiation at low temperature

    International Nuclear Information System (INIS)

    Mensch, W.

    1986-01-01

    The present thesis investigates the magnetic after-effect for neutron irradiated, polycrystalline iron-alpha for the temperature range 10 to 400 K by means of susceptibility measurements. 24 maxima of magnetic after-effect are found, which are related to different classes of defects. (BHO)

  6. Detection of irradiated peppers by viscosity measurement at extremely high pH

    International Nuclear Information System (INIS)

    Hayashi, Toru; Todoriki, Setsuko

    1996-01-01

    The viscosities of aqueous suspensions of irradiated peppers determined after heat gelatinization were influenced by the pH of the suspension to a greater degree than those of unirradiated ones. Viscosity measurement under an extremely alkaline condition (pH 13.8) resulted in a significant different between irradiated peppers and unirradiated ones, irrespective of the planting locality and storage period. All of the pepper samples irradiated at 5 kGy showed viscosity values significantly lower than unirradiated ones. (Author)

  7. Spin dynamics in the single molecule magnet Ni4 under microwave irradiation

    Science.gov (United States)

    de Loubens, Gregoire

    2009-03-01

    Quantum mechanical effects such as quantum tunneling of magnetization (QTM) and quantum phase interference have been intensively studied in single molecule magnets (SMMs). These materials have also been suggested as candidates for qubits and are promising for molecular spintronics. Understanding decoherence and energy relaxation mechanisms in SMMs is then both of fundamental interest and important for the use of SMMs in applications. Interestingly, the single-spin relaxation rate due to direct process of a SMM embedded in an elastic medium can be derived without any unknown coupling constant [1]. Moreover, nontrivial relaxation mechanisms are expected from collective effects in SMM single crystals, such as phonon superradiance or phonon bottleneck. In order to investigate the spin relaxation between the two lowest lying spin-states of the S=4 single molecule magnet Ni4, we have developed an integrated sensor that combines a microstrip resonator and micro-Hall effect magnetometer on a chip [2]. This sensor enables both real time studies of magnetization dynamics under pulse irradiation as well as simultaneous measurements of the absorbed power and magnetization changes under continuous microwave irradiation. The latter technique permits the study of small deviations from equilibrium under steady state conditions, i.e. small amplitude cw microwave irradiation. This has been used to determine the energy relaxation rate of a Ni4 single crystal as a function of temperature at two frequencies, 10 and 27.8 GHz. A strong temperature dependence is observed below 1.5 K, which is not consistent with a direct spin-phonon relaxation process. The data instead suggest that the spin relaxation is dominated by a phonon bottleneck at low temperatures and occurs by an Orbach process involving excited spin-levels at higher temperatures [3]. Experimental results will be compared with detailed calculations of the relaxation rate using the density matrix equation with the relaxation

  8. Topology optimization of the permanent magnet type MRI considering the magnetic field homogeneity

    International Nuclear Information System (INIS)

    Lee, Junghoon; Yoo, Jeonghoon

    2010-01-01

    This study is to suggest a concept design of the permanent magnet (PM) type magnetic resonance imaging (MRI) device based on the topology optimization method. The pulse currents in the gradient coils in the MRI device will introduce the effect of eddy currents in ferromagnetic material and it may worsen the quality of imaging. To equalize the magnetic flux in the PM type MRI device for good imaging, the eddy current effect in the ferromagnetic material must be reduced. This study attempts to use the topology optimization scheme for equalizing the magnetic flux in the measuring domain of the PM type MRI device using that the magnetic flux can be calculated directly by a commercial finite element analysis package. The density method is adopted for topology optimization and the sensitivity of the objective function is computed according to the density change of each finite element in the design domain. As a result, optimal shapes of the pole of the PM type MRI device can be obtained. The commercial package, ANSYS, is used for analyzing the magnetic field problem and obtaining the resultant magnetic flux.

  9. Changes of surface electron states of InP under soft X-rays irradiation

    International Nuclear Information System (INIS)

    Yang Zhian; Yang Zushen; Jin Tao; Qui Rexi; Cui Mingqi; Liu Fengqin

    1999-01-01

    Changes of surface electronic states of InP under 1 keV X-ray irradiation is studied by X-ray photoelectron spectroscopy (XPS) and ultraviolet ray energy spectroscopy (UPS). The results show that the soft X-ray irradiation has little effect on In atoms but much on P atoms. The authors analysed the mechanism of irradiation and explained the major effect

  10. Tests on irradiated magnet-insulator materials

    International Nuclear Information System (INIS)

    Schmunk, R.E.; Miller, L.G.; Becker, H.

    1983-01-01

    Fusion-reactor coils, located in areas where they will be only partially shielded, must be fabricated from materials which are as resistant to radiation as possible. They will probably incorporate resistive conductors with either water or cryogenic cooling. Inorganic insulators have been recommended for these situations, but the possibility exists that some organic insulators may be usuable as well. Results were previously reported for irradiation and testing of three glass reinforced epoxies: G-7, G-10, and G-11. Thin disks of these materials, nominally 0.5 mm thick by 11.1 mm diameter, were tested in compressive fatigue, a configuration and loading which represents reasonably well the magnet environment. In that work G-10 was shown to withstand repeated loading to moderately high stress levels without failure, and the material survived better at liquid nitrogen temperature than at room temperature

  11. (Ga,Fe)Sb: A p-type ferromagnetic semiconductor

    Energy Technology Data Exchange (ETDEWEB)

    Tu, Nguyen Thanh; Anh, Le Duc; Tanaka, Masaaki [Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656 (Japan); Hai, Pham Nam [Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656 (Japan); Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo 152-0033 (Japan)

    2014-09-29

    A p-type ferromagnetic semiconductor (Ga{sub 1−x},Fe{sub x})Sb (x = 3.9%–13.7%) has been grown by low-temperature molecular beam epitaxy (MBE) on GaAs(001) substrates. Reflection high energy electron diffraction patterns during the MBE growth and X-ray diffraction spectra indicate that (Ga,Fe)Sb layers have the zinc-blende crystal structure without any other crystallographic phase of precipitates. Magnetic circular dichroism (MCD) spectroscopy characterizations indicate that (Ga,Fe)Sb has the zinc-blende band structure with spin-splitting induced by s,p-d exchange interactions. The magnetic field dependence of the MCD intensity and anomalous Hall resistance of (Ga,Fe)Sb show clear hysteresis, demonstrating the presence of ferromagnetic order. The Curie temperature (T{sub C}) increases with increasing x and reaches 140 K at x = 13.7%. The crystal structure analyses, magneto-transport, and magneto-optical properties indicate that (Ga,Fe)Sb is an intrinsic ferromagnetic semiconductor.

  12. Proposal of Magnetic Circuit using Magnetic Shielding with Bulk-Type High Tc Superconductors

    Science.gov (United States)

    Fukuoka, Katsuhiro; Hashimoto, Mitsuo; Tomita, Masaru; Murakami, Masato

    Recently, bulk-type high Tc superconductors having a characteristic of critical current density over 104 A/cm2 in liquid nitrogen temperature (77K) on 1T, can be produced. They are promising for many practical applications such as a magnetic bearing, a magnetic levitation, a flywheel, a magnetic shielding and others. In this research, we propose a magnetic circuit that is able to use for the magnetic shield of plural superconductors as an application of bulk-type high Tc superconductors. It is a closed magnetic circuit by means of a toroidal core. Characteristics of the magnetic circuit surrounded with superconductors are evaluated and the possibility is examined. As the magnetic circuit of the ferrite core is surrounded with superconductors, the magnetic flux is shielded even if it leaked from the ferrite core.

  13. Grain boundary composition and irradiation-assisted stress corrosion cracking resistance in Type 348 stainless steel

    International Nuclear Information System (INIS)

    Jacobs, A.J.; Wozadlo, G.P.; Nakata, K.

    1994-01-01

    Scanning transmission electron microscopy (STEM) analyses, in-reactor swelling mandrel tests, and laboratory constant extension rate tensile (CERT) tests were conducted on nine custom type 348 (UNS S34800) stainless steel (SS) alloys in an attempt to correlate grain boundary composition with irradiation-assisted stress corrosion cracking (IASCC) resistance. Phosphorus (P) enrichment showed the best correlation with in-reactor test results, and chromium (Cr) depletion showed the best correlation with laboratory results. Silicon (Si) and P enrichment were found to depend quantitatively on the bulk concentrations of these elements. The amount of Cr depletion seemed dependent at least partially on the amounts of Si and/or P enrichment. Si and P enrichment and Cr depletion were suppressed by higher carbon (C) contents, such as that present in commercial-purity type 348 SS

  14. Discussions on performance of two types of permanent multipole magnets

    International Nuclear Information System (INIS)

    Xu Jianming; Xu Qing; Yin Zhaosheng

    1987-01-01

    The field distributions of MMD type and MW type multipole permanent magnets are calculated by means of programme POISCR and the results are summarized and discussed in this paper. The resutls show that, considering the nonlinearity of the real demagnetization curve of permanent magnet material, the field distributions of both types of permanent magnets with the same aperature are about the same but the field strength of MW type magnet with soft iron shield is higher than that of MMD type magnet

  15. Neutronic irradiation effect in FeNi alloys, observed by magnetic measurements

    International Nuclear Information System (INIS)

    Sciani, V.; Lucki, G.

    1986-01-01

    In this work some aspects of radiation damage are analysed through the influence of neutron irradiation on magnetic properties of FeNi alloys. The main points emphasized are: radiation enhanced diffusion, determination of the activation energy for diffusion process and vacancies supersaturation, which is an important parameter from technological point of view and a necessary condition for the void formation. (Author) [pt

  16. Effect of Carbon Doping on the Structure and Magnetic Phase Transition in (Mn,Fe2(P,Si))

    Science.gov (United States)

    Thang, N. V.; Yibole, H.; Miao, X. F.; Goubitz, K.; van Eijck, L.; van Dijk, N. H.; Brück, E.

    2017-08-01

    Given the potential applications of (Mn,Fe2(P,Si))-based materials for room-temperature magnetic refrigeration, several research groups have carried out fundamental studies aimed at understanding the role of the magneto-elastic coupling in the first-order magnetic transition and further optimizing this system. Inspired by the beneficial effect of the addition of boron on the magnetocaloric effect of (Mn,Fe2(P,Si))-based materials, we have investigated the effect of carbon (C) addition on the structural properties and the magnetic phase transition of Mn_{1.25}Fe_{0.70}P_{0.50}Si_{0.50}C_z and Mn_{1.25}Fe_{0.70}P_{0.55}Si_{0.45}C_z compounds by x-ray diffraction, neutron diffraction and magnetic measurements in order to find an additional control parameter to further optimize the performance of these materials. All samples crystallize in the hexagonal Fe_2P-type structure (space group P-62m), suggesting that C doping does not affect the phase formation. It is found that the Curie temperature increases, while the thermal hysteresis and the isothermal magnetic entropy change decrease by adding carbon. Room-temperature neutron diffraction experiments on Mn_{1.25}Fe_{0.70}P_{0.55}Si_{0.45}C_z compounds reveal that the added C substitutes P/Si on the 2 c site and/or occupies the 6 k interstitial site of the hexagonal Fe_2P-type structure.

  17. High-aspect ratio microstructures in p-type GaAs and InP created by proton beam writing

    International Nuclear Information System (INIS)

    Menzel, F.; Spemann, D.; Butz, T.

    2011-01-01

    With proton beam writing (PBW) and subsequent electrochemical etching in HF-solution the creation of high-aspect ratio microstructures in p-type InP was performed for the first time. Microstructures with high surface quality as well as high-aspect ratio possessing lateral dimensions down to 1 μm were produced. Furthermore, free-standing microstructures were created in this material by a combined irradiation with 2.25 MeV protons and 1.125 MeV H 2 + molecules, were the smallest structure dimension of 0.6 μm was achieved for a horizontal needle. The creation of nearly perfect circular microstructures indicates that the crystal structure has little effect on the structuring process by PBW in this material. Moreover, the effect of reduced etching inside of closed irradiation patterns, already known from Si and GaAs, was observed also in InP. In further PBW experiments and subsequent electrochemical etching with KOH-solution p-type GaAs microstructures were produced. By using a 4-fold higher etch current density of 45 mA/cm 2 compared to former PBW experiments on this material the quality of the microstructures could be improved significantly leading to high aspect-ratio structures with minimum lateral sizes of ∼1 μm, nearly vertical side walls as well as circular microstructures. This shows the reduced influence of the crystal structure on the shape of the microstructures compared to experiments with lower etch current density where only flat microstructures with inclined side walls determined by the crystal structure could be created.

  18. Effect of low temperature neutron irradiation on the magnetoresistivity in stabilizer materials for a superconducting magnet

    International Nuclear Information System (INIS)

    Nakata, Kiyotomo; Tada, Naobumi; Masaoka, Isao; Takamura, Saburo.

    1985-01-01

    Magnetoresistivity changes caused by neutron irradiation at 5 K, annealing up to 300 K and cyclic irradiation are studied in copper and aluminuim stabilizer materials at 4.2 K. The radiation-induced resistivity in Al is about three times as large as that in Cu, and the resistivities in both Al and Cu are independent of the purity and the degree of cold-work of the samples. The radiation-induced magnetoresistivity of the high purity Cu with R.R.R. (R sub(298 K)/R sub(4.2 K)) of 1400 is larger than that of the impure Cu with R.R.R. of 300 and 280. The magnetoresistivities of the high purity Cu and Al with R.R.R. of 1500 increase with the magetic field. Magnetoresistivity change with the magnetic field in the irradiated Cu mostly follows Kohler's rule, and that in the irradiated Al does not follow the rule at high magnetic fields. By the annealing at 300 K after the irradiation, the radiation-induced resistivity is completely annihilated in the Al, but about 20 % of the resistivity retains in the full-annealed Cu and the retained resistivity is accumulated during the cyclic irradiation. Though the accumulated resistivity in the cold-worked Cu is smaller than that in the full-annealed one, the resistivity before irradiation in the cold-worked samples is very large. From the above results, the full-annealed Cu with R.R.R. of about 300 is considered to be the best material as a stabilizer used under irradiation. (author)

  19. Magnetism by interfacial hybridization and p-type doping of MoS2 in Fe4N/MoS2 superlattices: A first-principles study

    KAUST Repository

    Feng, Nan

    2014-03-26

    Magnetic and electronic properties of Fe4N(111)/MoS 2(√3 × √3) superlattices are investigated by first-principles calculations, considering two models: (I) FeIFe II-S and (II) N-S interfaces, each with six stacking configurations. In model I, strong interfacial hybridization between FeI/Fe II and S results in magnetism of monolayer MoS2, with a magnetic moment of 0.33 μB for Mo located on top of Fe I. For model II, no magnetism is induced due to weak N-S interfacial bonding, and the semiconducting nature of monolayer MoS2 is preserved. Charge transfer between MoS2 and N results in p-type MoS2 with Schottky barrier heights of 0.5-0.6 eV. Our results demonstrate that the interfacial geometry and hybridization can be used to tune the magnetism and doping in Fe4N(111)/MoS2(√3 × √3) superlattices. © 2014 American Chemical Society.

  20. Magnetism by interfacial hybridization and p-type doping of MoS2 in Fe4N/MoS2 superlattices: A first-principles study

    KAUST Repository

    Feng, Nan; Mi, Wenbo; Cheng, Yingchun; Guo, Zaibing; Schwingenschlö gl, Udo; Bai, Haili

    2014-01-01

    Magnetic and electronic properties of Fe4N(111)/MoS 2(√3 × √3) superlattices are investigated by first-principles calculations, considering two models: (I) FeIFe II-S and (II) N-S interfaces, each with six stacking configurations. In model I, strong interfacial hybridization between FeI/Fe II and S results in magnetism of monolayer MoS2, with a magnetic moment of 0.33 μB for Mo located on top of Fe I. For model II, no magnetism is induced due to weak N-S interfacial bonding, and the semiconducting nature of monolayer MoS2 is preserved. Charge transfer between MoS2 and N results in p-type MoS2 with Schottky barrier heights of 0.5-0.6 eV. Our results demonstrate that the interfacial geometry and hybridization can be used to tune the magnetism and doping in Fe4N(111)/MoS2(√3 × √3) superlattices. © 2014 American Chemical Society.

  1. P-Type Silicon Strip Sensors for the Future CMS Tracker

    CERN Document Server

    The Tracker Group of the CMS Collaboration

    2016-01-01

    The upgrade to the High-Luminosity LHC (HL-LHC) is expected to increase the LHC design luminosity by an order of magnitude. This will require silicon tracking detectors with a significantly higher radiation hardness. The CMS Tracker Collaboration has conducted an irradiation and measurement campaign to identify suitable silicon sensor materials and strip designs for the future outer tracker at CMS. Based on these results, the collaboration has chosen to use n-in-p type strip and macro-pixel sensors and focus further investigations on the optimization of that sensor type. This paper describes the main measurement results and conclusions that motivated this decision.

  2. Cytogenetic damage, oncogenic transformation and p53 induction in human epithelial cells in response to irradiation

    Science.gov (United States)

    Armitage, Mark

    Ionizing radiation can have several different effects on cells, some are almost instantaneous such as the generation of DNA damage, other cellular responses take a matter of minutes or hours - DNA repair protein induction/activation, and others may take months or even years to be manifested - carcinogenesis. Human epithelial cell lines derived from both normal, non-neoplastic tissues and from a malignant source were cultured in order to examine several effects of ionizing radiation on such cell types. Cells not from a malignant source were previously immortalized by viral infection or by transfection with viral sequences. Simian virus 40 immortalised uroepithelial cells (SV-HUC) were found to be approximately a factor of two fold more radioresistant than cells of malignant origin (T24) in terms of unrepaired clastogenic damage i.e. assessment of micronuclei levels following irradiation. SV-HUC lines unlike T24 cells are non-tumourigenic when inoculated into nude athymic mice. SV-HUC lines proved very resistant to full oncogenic transformation using radiation and chemical carcinogens. However, morphological alterations and decreased anchorage dependant growth was observed in post carcinogen treated cells after appropriate cell culture conditions were utilized. The progression from this phenotype to a fully tumourigenic one was not recorded in this study. The ability of ionizing radiation to induce increased levels of the nuclear phosphoprotein p53 was also assessed using several different cell lines. SV- HUC and T24 cell lines failed to exhibit any increased p53 stabilization following irradiation. One cell line, a human papilloma virus transformed line (HPV) did show an approximate two fold increase of the wild type p53 protein after treatment with radiation. Only the cell line HPV showed any cell cycle delay, resulting in accumulation of cells in the G2/M compartment in post irradiation cell cycle analysis. The status of p53 was also assessed i.e. wild type or

  3. Proton irradiation induced defects in Cd and Zn doped InP

    International Nuclear Information System (INIS)

    Rybicki, G.C.; Williams, W.S.

    1993-01-01

    Proton irradiation induced defects in Zn and Cd doped InP have been studied by deep level transient spectroscopy, (DLTS). After 2 MeV proton irradiation the defects H4 and H5 were observed in lightly Zn doped InP, while the defects H3 and H5 were observed in more heavily Zn and Cd doped InP. The defect properties were not affected by the substitution of Cd for Zn, but the introduction rate of H5 was lower in Cd doped InP. The annealing rate of defects was also higher in Cd doped InP. The use of Cd doped InP may thus result in an InP solar cell with even greater radiation resistance

  4. Construction of pEgr.p-TNFα and its expression in NIH3T3 cells induced by ionizing irradiation

    International Nuclear Information System (INIS)

    Wu Congmei; Li Xiuyi; Liu Shuzheng

    2001-01-01

    Objective: To isolate and amplify Egr-1 promoter, construct pEgr.p-TNFα and study its response to different doses of ionizing radiation. Methods: Egr-1 promote was isolated from genomic DNA by PCR to construct pEgr.p-TNFα expression plasmid. Plasmids were transfected into NIH3T3 cells with liposome and the expression level of TNFα was detected by ELISA after irradiation with different doses of X-ray. Results: The sequence of Egr-1 promoter obtained was essentially same as reported. Egr-1 promoter and TNF α cDNA were inserted into expression vector correctly. Eight hours after irradiation with different doses of X-rays, the expression level of TNFα was higher than that of nonirradiated group (P< 0.05-0.001). Conclusion: Egr-1 promoter obtained can be activated by ionizing irradiation and regulate the expression of downstream gene. Low dose irradiation is for the first time found to be able to induce the expression of the downstream gene. the observation may be of potential significance in tumor therapy

  5. Performance, Defect Behavior and Carrier Enhancement in Low Energy, Proton Irradiated p(+)nn(+) InP Solar Cells

    Science.gov (United States)

    Weinberg, I.; Rybicki, G. C.; Vargas-Aburto, C.; Jain, R. K.; Scheiman, D.

    1994-01-01

    InP p(+)nn(+) cells, processed by MOCVD, were irradiated by 0.2 MeV protons and their performance and defect behavior observed to a maximum fluence of 10(exp 13)/sq cm. Their radiation induced degradation, over this fluence range, was considerably+less than observed for similarly irradiated, diffused junction n p InP cells. Significant degradation occurred in both the cell's emitter and base regions the least degradation occurring in the depletion region. A significant increase in series resistance occurs at the highest fluenc.e. Two majority carrier defect levels, E7 and E10, are observed by DLTS with activation energies at (E(sub C) - 0.39)eV and (E(sub C) - 0.74)eV respectively. The relative concentration of these defects differs considerably from that observed after 1 MeV electron irradiation. An increased carrier concentration in the cell's n-region was observed at the highest proton fluence, the change in carrier concentration being insignificant at the lower fluences. In agreement with previous results, for 1 and 1.5 MeV electron irradiated InP p(+)n junctions, the defect level E10 is attributed to a complex between zinc, diffused into the n-region from the zinc doped emitter, and a radiation induced defect. The latter is assumed to be either a phosphorus vacancy or interstitial. The increased, or enhanced carrier concentration is attributed to this complex acting as a donor.

  6. Thorax irradiation triggers a local and systemic accumulation of immunosuppressive CD4+ FoxP3+ regulatory T cells

    International Nuclear Information System (INIS)

    Wirsdörfer, Florian; Cappuccini, Federica; Niazman, Muska; Leve, Simone de; Westendorf, Astrid M; Lüdemann, Lutz; Stuschke, Martin; Jendrossek, Verena

    2014-01-01

    Lymphocyte infiltration is a common feature of radiation-induced pneumonitis and fibrosis, but their contribution to the pathogenic processes is still unclear. Here, we addressed the impact of thorax irradiation on the T cell compartment with a focus on immunosuppressive regulatory T cells (Treg). C57BL/6 wild type mice (WT) received anesthesia only (sham controls, 0 Gy) or were exposed to a single dose of whole thorax irradiation (15 Gy). Immune cells from lung tissue, spleen, and cervical lymph nodes were collected 10 to 84 days post-irradiation and phenotypically characterized by flow cytometry. Whole thorax irradiation provoked an increased influx of CD3+ T cells at 42 and 84 days post-irradiation. In contrast, local irradiation caused a sustained reduction in CD3+ T cells in peripheral lymphoid tissues. Interestingly, we observed a significant local and systemic increase in the fraction of CD4+ T cells expressing the transcription factor forkhead box P3 (FoxP3), the phenotypic marker for murine Treg, at day 21 post-irradiation. The accumulation of Treg was associated with increased levels of T cells expressing surface proteins characteristic for recruitment and immunosuppressive activity, e.g. CD103, CTLA-4 and CD73. Importantly, Treg isolated at this time point were able to suppress CD4+ effector T cells to a similar extent as Treg isolated from control mice. The response of the adaptive immune system to whole thorax irradiation is characterized by local immunoactivation and systemic immunosuppression. The transient accumulation of immunosuppressive CD4+ FoxP3+ Treg may be required to protect the lung against excessive inflammation-induced tissue damage. Further investigations shall define the mechanisms underlying the accumulation of Treg and their role for the pathogenesis of radiation-induced lung disease

  7. Beta-spectrometer with magnetic filter of mini orange type

    International Nuclear Information System (INIS)

    Gorozhankin, V.M.; Gromov, K.Ya.; Kalinnikov, V.G.; Sereeter, Z.; Fominykh, V.I.; Malikov, Sh.R.; Yuldashev, M.B.

    1997-01-01

    At the ISOL facility YASNAPP-2 a β-spectrometer with a magnetic filter of the miniorange type is constructed to measure γ-ray internal conversion coefficients. The magnetic filter of the mini orange type is an assemblage of permanent magnets creating a toroidal magnetic field perpendicular to the electron trajectories from the source to the Si(Li) detector. The chosen profile of the permanent magnets allowed electron registration in the defined energy energy interval with some transmission increase. There are two sets of permanent magnets of the different thickness. Varying the type and number of permanent magnets one can set the detected electron energy intervals in a 50-2500 keV range. The efficiency of the spectrometer was investigated for different assemblages of the mini orange magnet. The facility can be used for the e-γ coincidence investigation. (A.A.D.)

  8. Fatigue behavior of Type 316 stainless steel following neutron irradiation inducing helium

    International Nuclear Information System (INIS)

    Grossbeck, M.L.; Liu, K.C.

    1980-01-01

    Since a tokamak reactor operates in a cyclic mode, thermal stresses will result in fatigue in structural components, especially in the first wall and blanket. There has been limited work on fatigue in irradiated alloys but none on irradiated materials containing significant amounts of irradiation-induced helium. To provide scoping data and to study the effects of irradiation on fatigue behavior, 20%-cold-worked type 316 stainless steel from the MFE reference heat was studied

  9. Effects of proton irradiation on structure of NdFeB permanent magnets studied by X-ray diffraction and X-ray absorption fine structure

    International Nuclear Information System (INIS)

    Yang, L.; Zhen, L.; Xu, C.Y.; Sun, X.Y.; Shao, W.Z.

    2011-01-01

    The effects of proton irradiation on the structure of NdFeB permanent magnet were investigated by X-ray diffraction and X-ray absorption fine structure (XAFS). The results reveal that proton irradiation has no effect on the long-range structure, but significantly affects the atomic local structure of the NdFeB magnet. The alignment degree of the magnet decreases and the internal stress of the lattice increases after proton irradiation. XAFS results show that the coordination number of Fe-Nd in the first neighboring coordination shell of the Fe atoms decreases and the disorder degree increases.

  10. Effects of proton irradiation on structure of NdFeB permanent magnets studied by X-ray diffraction and X-ray absorption fine structure

    Energy Technology Data Exchange (ETDEWEB)

    Yang, L. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Zhen, L., E-mail: lzhen@hit.edu.c [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Xu, C.Y.; Sun, X.Y.; Shao, W.Z. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2011-01-15

    The effects of proton irradiation on the structure of NdFeB permanent magnet were investigated by X-ray diffraction and X-ray absorption fine structure (XAFS). The results reveal that proton irradiation has no effect on the long-range structure, but significantly affects the atomic local structure of the NdFeB magnet. The alignment degree of the magnet decreases and the internal stress of the lattice increases after proton irradiation. XAFS results show that the coordination number of Fe-Nd in the first neighboring coordination shell of the Fe atoms decreases and the disorder degree increases.

  11. Magnetic regimes in amorphous Ni--Fe--P--B alloys

    International Nuclear Information System (INIS)

    Durand, J.

    1976-10-01

    A complete substitution of iron for nickel was obtained by splat-cooling in amorphous alloys of composition (Ni/sub 100-y/Fe/sub y/) 79 P 13 B 8 . Results of high-field magnetization (up to 70 kOe), ac and dc low-field susceptibility, Curie temperature, and resistivity measurements over a temperature range of 1.7 to 300 0 K are reported. The Ni 79 P 13 B 8 alloy is not ferromagnetic, but the magnetization behavior as a function of field and temperature is typically that of alloys in the critical concentration range for ferromagnetism. The Fe 79 P 13 B 8 alloy is ferromagnetic with a Curie temperature T/sub c/ of 616 0 K. For y = 1 at. percent, the Fe atoms are magnetic. The variation of the moment per Fe atom as a function of y is discussed. When y is increased, the Ni atoms are likely to be polarized progressively and the moment per Ni atom would be roughly constant for y equal to or greater than 30 at. percent. Various magnetic behaviors were defined as a function of the Fe content. The value of T/sub c/ reaches a maximum for y similarly ordered 90 at. percent and extrapolates to zero for y similarly ordered 7 at. percent. Alloys within the range 1 equal to or less than y equal to or less than 10 at. percent did not exhibit well-defined Curie transition, but sharp maxima in low-field susceptibility measurements were observed at T/sub M/. The value of T/sub M/ is proportional to y for 1 equal to or less than y equal to or less than 4 at. percent, as in classical spin-glass regimes. For 4 less than y equal to or less than 10 at. percent, the variation of T/sub M/ as a function of y implies a more complicated type of magnetic ordering (micromagnetism or superparamagnetism). Homogeneous ferromagnetic ordering emerges only for y greater than 10 at. percent. Results of resistivity measurements are discussed in relation to the magnetic properties of different regimes in the magnetic phase diagram. 6 figures, 2 tables

  12. Delayed expression of apoptosis in X-irradiated human leukemic MOLT-4 cells transfected with mutant p53

    International Nuclear Information System (INIS)

    Nakano, Hisako; Yonekawa, Hiromichi; Shinohara, Kunio

    2003-01-01

    The effects of X-rays on cell survival, apoptosis, and long-term response in the development of cell death as measured by the dye exclusion test were studied in human leukemic MOLT-4 cells (p53 wild-type) stably transfected with a mutant p53 cDNA expression vector. Cell survival, as determined from colony-forming ability, was increased in an expression level dependent manner, but the increase was partial even with the highest-expressing clone (B3). This contrasts with the prior observation that cell death and apoptosis in B3 are completely inhibited at 24 h after irradiation with 1.8 Gy of X-rays. The examination of B3 cells incubated for longer than 24 h after X-irradiation showed a delay in the induction of cell death and apoptosis. Western blot analysis revealed that the time required to reach the highest level of wild-type p53 protein in B3 was longer than the time in MOLT-4 and that the p53 may be stabilized by the phosphorylation at Ser-15. These results suggest that the introduction of mutant p53 into MOLT-4 merely delays the development of apoptosis, during which the cells could repair the damage induced by X-rays, and results in the partial increase in cell survival. (author)

  13. Effect of using type A radiation for dose reconstruction in type B irradiated material: A microdosimetry approach

    International Nuclear Information System (INIS)

    Piters, T.M.; Chernov, V.

    2008-01-01

    A model is proposed to explain that in previously γ irradiated calcite, the yield after additive β irradiation tends to incline to the saturation yield of the β radiation even if that yield is lower than the yield after the γ irradiation. However, the proposed model is not specific for calcite and in fact all calculations are done in a fictive material. The proposed model considers, in contrast to existing models, the track nature of γ and β radiations and that these different types of radiations can be distinguished by the dose distribution inside their tracks. The determination of the dose distribution in the tracks for the different types of irradiations is quite complicated and instead we approximate the γ and β tracks by type A and B tracks that have different but homogeneously distributed dose in their track volumes. The trapping of generated free charges in the track was calculated with a simple one electron-one hole trap model. To obtain the total dose response (the average concentration of occupied traps as a function of dose), the yield in one point was averaged over all possible configurations of track overlapping in that point. We determined the slope of the initial part of the response curve (low dose sensitivity) and the saturation yield as function of the track dose. It is observed that the low dose sensitivity and saturation yield both decrease with increasing track dose. Simulations of the response to sequential irradiation first by type A radiation with a 64 Gy track dose and then followed by type B radiation with a track dose of 128 Gy using our model show a similar effect as observed in calcite demonstrating that the track nature of radiation is a plausible cause for the observed effect

  14. Quantum renormalizations in anisotropic multisublattice magnets and the modification of magnetic susceptibility under irradiation

    Science.gov (United States)

    Val'kov, V. V.; Shustin, M. S.

    2015-11-01

    The dispersion equation of a strongly anisotropic one-dimensional magnet catena-[FeII(ClO4)2{FeIII(bpca)2}]ClO4 containing alternating high-spin (HS) ( S = 2) and low-spin (LS) ( S = 1/2) iron ions is obtained by the diagram technique for Hubbard operators. The analysis of this equation yields six branches in the excitation spectrum of this magnet. It is important that the crystal field for ions with spin S = 2 is described by the Hamiltonian of single-ion easy-plane anisotropy, whose orientation is changed by 90° when passing from one HS iron ion to another. The U( N) transformation technique in the atomic representation is applied to diagonalize a single-ion Hamiltonian with a large number of levels. It is shown that the modulation of the orientation of easy magnetization planes leads to a model of a ferrimagnet with easy-axis anisotropy and to the formation of energy spectrum with a large gap. For HS iron ions, a decrease in the mean value of the spin projection due to quantum fluctuations is calculated. The analysis of the specific features of the spectrum of elementary excitations allows one to establish a correspondence to a generalized Ising model for which the magnetic susceptibility is calculated in a wide range of temperatures by the transfer-matrix method. The introduction of a statistical ensemble that takes into account the presence of chains of different lengths and the presence of iron ions with different spins allows one to describe the experimentally observed modification of the magnetic susceptibility of the magnet under optical irradiation.

  15. Influence of gastric pH modifiers on development of intestinal metaplasia induced by X-irradiation in rats

    International Nuclear Information System (INIS)

    Watanabe, Hiromitsu; Okamoto, Taro; Fudaba, Yasuhiro; Ogundigie, P.S.; Ito, Akihiro

    1993-01-01

    The influence of gastric pH on intestinal metaplasia was examined in male Crj:CD(SD) rats. At the age of 5 weeks, animals were irradiated with two 10 Gy doses of X-rays to the gastric region at a 3-day interval (total 20 Gy), and 6 months after irradiation, received either secretin or histamine in silicon tubes for 2 months or had their bilateral submandibular salivary glands removed. The incidences of intestinal metaplasia in the fundus of animals after administration of secretin or histamine, or removal of the salivary glands were reduced, along with the pH values, as compared with values for rats given X-rays alone. In both the pyloric and the fundic gland mucosae, the numbers of alkaline phosphatase (ALP)-positive foci and type B metaplasias (intestinal crypts without Paneth cells) were also significantly decreased (P<0.01). In a second experiment, started six months after irradiation, rats were kept on 1% sodium chloride (NaCl) diet for 6 months. Subsequent removal of salivary glands along with histamine treatment brought about a marked drop in pH and in numbers of ALP-positive foci after three and five days. The present results thus indicated that development and maintenance of intestinal metaplasia can be influenced by a decrease of pH value. (author)

  16. Effects of C3+ ion irradiation on structural, electrical and magnetic properties of Ni nanotubes

    Science.gov (United States)

    Shlimas, D. I.; Kozlovskiy, A. L.; Zdorovets, M. V.; Kadyrzhanov, K. K.; Uglov, V. V.; Kenzhina, I. E.; Shumskaya, E. E.; Kaniukov, E. Y.

    2018-03-01

    Ion irradiation is an attractive method for obtaining nanostructures that can be used under extreme conditions. Also, it is possible to control the technological process that allows obtaining nanomaterials with new properties at ion irradiation. In this paper, we study the effect of irradiation with 28 MeV C3+ ions and fluences up to 5 × 1011 cm-2 on the structure and properties of template-synthesized nickel nanotubes with a length of 12 μm, with diameters of 400 nm, and a wall thickness of 100 nm. It is demonstrated that the main factor influencing the degradation of nanostructures under irradiation in PET template is the processes of mixing the material of nanostructures with the surrounding polymer. The influence of irradiation with various fluences on the crystal structure, electrical and magnetic properties of nickel nanotubes is studied.

  17. Effects on the glucose metabolism in type II diabetes model mice treated with dose-rates irradiation

    International Nuclear Information System (INIS)

    Nomura, Takaharu; Sakai, Kazuo

    2004-01-01

    The effects of low-dose rate gamma-irradiation on the type II diabetes mellitus were investigated in C57BL/KsJ-ab/db (db mouse). This mouse develops the type II diabetes within 8 weeks of the birth due to a dysfunction of the insulin receptors. As a result the db mouse shows obese and exhibits hyperinsulinism. Ten-week old female mice (12 mice in each group) were irradiated with gamma-rays at 0.35 mGy/hr, 0.65 mGy/hr or 1.2 mGy/hr in the low-dose rate irradiation facility in the Low Dose Radiation Research Center. The level of plasma glucose and insulin was measured. After 2 weeks irradiation, the glucose level slightly increased, however the difference between the irradiated mice and non-irradiated groups was not significant. The plasma insulin concentration decreased in the non-irradiated group to half of the initial level. In the irradiated group, it also decreased but in the group of 0.65 mGy/hr and 0.35 mGy/hr, it was significantly differed from that in the non-irradiated group. In the glucose tolerance test, plasma glucose level increased shortly after 0.1 mg/head glucose injection by mouth and reached to a peak at 90-120 min after the injection. The glucose level of the non-irradiated mice was slightly higher than that of irradiated mice. The plasma insulin level of non-irradiated group was enhanced after the injection and maintained the level during the test. However the levels of irradiated mice were decreased at 30-60 min after the injection. Both the level of non-irradiated an irradiated was almost same but the non-irradiated one was a little high. In all of mice, the plasma insulin level was highly elevated right after the 0.05 units/head insulin injection by i.p. and the levels were also gradually decreased. The level of the non-irradiated group was slowly decreased and was higher than the irradiated mice. The plasma glucose levels of all mice did not change after the test; however, the levels of irradiated mice were slightly lower than that of non-irradiated

  18. Effects of electron and proton irradiations on n/p and p/n GaAs cells grown by MOCVD

    International Nuclear Information System (INIS)

    Weinberg, I.; Swartz, C.K.; Hart, R.E. Jr.

    1987-01-01

    State-of-the-art n/p and p/n heteroface GaAs cells, processed by metal organic chemical vapor deposition, were irradiated by 1 MeV electrons and 37 MeV protons and their performance determined as a function of fluence. It was found that the p/n cells were more radiation resistant than the n/p cells. The increased loss in the n/p cells was attributed to increases in series resistance and losses in the p-region resulting from the irradiation. The greater loss in fill factor observed for the n/p cells introduces the possibility that the presently observed superiority of the p/n cells may not be an intrinsic property of this configuration in GaAs

  19. Carbon-ion beam irradiation kills X-ray-resistant p53-null cancer cells by inducing mitotic catastrophe.

    Directory of Open Access Journals (Sweden)

    Napapat Amornwichet

    Full Text Available BACKGROUND AND PURPOSE: To understand the mechanisms involved in the strong killing effect of carbon-ion beam irradiation on cancer cells with TP53 tumor suppressor gene deficiencies. MATERIALS AND METHODS: DNA damage responses after carbon-ion beam or X-ray irradiation in isogenic HCT116 colorectal cancer cell lines with and without TP53 (p53+/+ and p53-/-, respectively were analyzed as follows: cell survival by clonogenic assay, cell death modes by morphologic observation of DAPI-stained nuclei, DNA double-strand breaks (DSBs by immunostaining of phosphorylated H2AX (γH2AX, and cell cycle by flow cytometry and immunostaining of Ser10-phosphorylated histone H3. RESULTS: The p53-/- cells were more resistant than the p53+/+ cells to X-ray irradiation, while the sensitivities of the p53+/+ and p53-/- cells to carbon-ion beam irradiation were comparable. X-ray and carbon-ion beam irradiations predominantly induced apoptosis of the p53+/+ cells but not the p53-/- cells. In the p53-/- cells, carbon-ion beam irradiation, but not X-ray irradiation, markedly induced mitotic catastrophe that was associated with premature mitotic entry with harboring long-retained DSBs at 24 h post-irradiation. CONCLUSIONS: Efficient induction of mitotic catastrophe in apoptosis-resistant p53-deficient cells implies a strong cancer cell-killing effect of carbon-ion beam irradiation that is independent of the p53 status, suggesting its biological advantage over X-ray treatment.

  20. Electrical characterization of proton irradiated p+-n-n+ Si diode

    International Nuclear Information System (INIS)

    Kim, J.H.; Lee, D.U.; Kim, E.K.; Bae, Y.H.

    2006-01-01

    Electrical characterization of p + -n-n + Si power electric diodes was done with proton irradiation. The kinetic energies of irradiated protons were 2.32, 2.55 and 2.97MeV, and for each energy condition, doses of 1x10 11 , 1x10 12 and 1x10 13 cm -2 were given. By modulating the kinetic energy, the proton penetration depth into Si crystal could be adjusted to the range of 55-90μm, and then controlled to the special depth regions such as junction region, depletion region and neutral region over the depletion layer in the p + -n-n + diode structure. Defects produced by the proton irradiation affected to electrical property of the Si diode because of their carrier trapping, and then the reverse recovery time was improved from 240 to 50ns. It appeared that the defect states with activation energies of 0.47 and 0.54eV may be responsible for the decrease of the minority carrier lifetime in the proton-irradiated diode with 2.97MeV energy and 1x10 13 cm -2 doses

  1. Magnetic and topographical modifications of amorphous Co–Fe thin films induced by high energy Ag{sup 7+} ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Pookat, G.; Hysen, T. [Department of Physics, Cochin University of Science and Technology, Cochin 682022, Kerala (India); Al-Harthi, S.H.; Al-Omari, I.A. [Department of Physics, Sultan Qaboos University, Muscat, P.O. Box 36, Code 123 (Oman); Lisha, R. [Department of Physics, Cochin University of Science and Technology, Cochin 682022, Kerala (India); Avasthi, D.K. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110 067 (India); Anantharaman, M.R., E-mail: mra@gmail.com [Department of Physics, Cochin University of Science and Technology, Cochin 682022, Kerala (India)

    2013-09-01

    We have investigated the effects of swift heavy ion irradiation on thermally evaporated 44 nm thick, amorphous Co{sub 77}Fe{sub 23} thin films on silicon substrates using 100 MeV Ag{sup 7+} ions fluences of 1 × 10{sup 11} ions/cm{sup 2}, 1 × 10{sup 12} ions/cm{sup 2}, 1 × 10{sup 13} ions/cm{sup 2}, and 3 × 10{sup 13} ions/cm{sup 2}. The structural modifications upon swift heavy irradiation were investigated using glancing angle X-ray diffraction. The surface morphological evolution of thin film with irradiation was studied using Atomic Force Microscopy. Power spectral density analysis was used to correlate the roughness variation with structural modifications investigated using X-ray diffraction. Magnetic measurements were carried out using vibrating sample magnetometry and the observed variation in coercivity of the irradiated films is explained on the basis of stress relaxation. Magnetic force microscopy images are subjected to analysis using the scanning probe image processor software. These results are in agreement with the results obtained using vibrating sample magnetometry. The magnetic and structural properties are correlated.

  2. Magnetization measurements and XMCD studies on ion irradiated iron oxide and core-shell iron/iron-oxide nanomaterials

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Maninder; Qiang, You; Jiang, Weilin; Pearce, Carolyn; McCloy, John S.

    2014-12-02

    Magnetite (Fe3O4) and core-shell iron/iron-oxide (Fe/Fe3O4) nanomaterials prepared by a cluster deposition system were irradiated with 5.5 MeV Si2+ ions and the structures determined by x-ray diffraction as consisting of 100% magnetite and 36/64 wt% Fe/FeO, respectively. However, x-ray magnetic circular dichroism (XMCD) indicates similar surfaces in the two samples, slightly oxidized and so having more Fe3+ than the expected magnetite structure, with XMCD intensity much lower for the irradiated core-shell samples indicating weaker magnetism. X-ray absorption spectroscopy (XAS) data lack the signature for FeO, but the irradiated core-shell system consists of Fe-cores with ~13 nm of separating oxide crystallite, so it is likely that FeO exists deeper than the probe depth of the XAS (~5 nm). Exchange bias (Hex) for both samples becomes increasingly negative as temperature is lowered, but the irradiated Fe3O4 sample shows greater sensitivity of cooling field on Hex. Loop asymmetries and Hex sensitivities of the irradiated Fe3O4 sample are due to interfaces and interactions between grains which were not present in samples before irradiation as well as surface oxidation. Asymmetries in the hysteresis curves of the irradiated core/shell sample are related to the reversal mechanism of the antiferromagnetic FeO and possibly some near surface oxidation.

  3. Structural and magnetic properties of nano-sized NiCuZn ferrites synthesized by co-precipitation method with ultrasound irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Harzali, Hassen, E-mail: harzali@mines-albi.fr [Laboratory of Applied Mineral Chemistry, Faculty of Sciences, University Tunis ElManar, Campus University, Farhat Hached El-Manar, 2092 Tunis (Tunisia); Saida, Fairouz; Marzouki, Arij; Megriche, Adel [Laboratory of Applied Mineral Chemistry, Faculty of Sciences, University Tunis ElManar, Campus University, Farhat Hached El-Manar, 2092 Tunis (Tunisia); Baillon, Fabien; Espitalier, Fabienne [Université de Toulouse, Mines Albi, CNRS, Centre RAPSODEE, Campus Jarlard, F-81013 Albi CT cedex 09 (France); Mgaidi, Arbi [Laboratory of Applied Mineral Chemistry, Faculty of Sciences, University Tunis ElManar, Campus University, Farhat Hached El-Manar, 2092 Tunis (Tunisia); Taibah University, Faculty of Sciences & art, Al Ula (Saudi Arabia)

    2016-12-01

    Sonochemically assisted co-precipitation has been used to prepare nano-sized Ni–Cu–Zn-ferrite powders. A suspension of constituent hydroxides was ultrasonically irradiated for various times at different temperatures with high intensity ultrasound radiation using a direct immersion titanium horn. Structural and magnetic properties were investigated using X-diffraction (XRD), FT-IR spectroscopy, transmission electron microscopy (TEM), Nitrogen adsorption at 77 K (BET) and Vibrating sample magnetometer (VSM). Preliminary experimental results relative to optimal parameters showed that reaction time t=2 h, temperature θ=90 °C and dissipated Power P{sub diss}=46.27 W. At these conditions, this work shows the formation of nanocrystalline single-phase structure with particle size 10–25 nm. Also, ours magnetic measurements proved that the sonochemistry method has a great influence on enhancing the magnetic properties of the ferrite. - Highlights: • Coprecipitation experiments were carried out with ultrasound. • The spinel ferrite NiCuZn was perfectly synthesized by ultrasound. • The saturation magnetization and crystals size are found to be correlated as the dissipated power was varied.

  4. Structural and magnetic properties of nano-sized NiCuZn ferrites synthesized by co-precipitation method with ultrasound irradiation

    International Nuclear Information System (INIS)

    Harzali, Hassen; Saida, Fairouz; Marzouki, Arij; Megriche, Adel; Baillon, Fabien; Espitalier, Fabienne; Mgaidi, Arbi

    2016-01-01

    Sonochemically assisted co-precipitation has been used to prepare nano-sized Ni–Cu–Zn-ferrite powders. A suspension of constituent hydroxides was ultrasonically irradiated for various times at different temperatures with high intensity ultrasound radiation using a direct immersion titanium horn. Structural and magnetic properties were investigated using X-diffraction (XRD), FT-IR spectroscopy, transmission electron microscopy (TEM), Nitrogen adsorption at 77 K (BET) and Vibrating sample magnetometer (VSM). Preliminary experimental results relative to optimal parameters showed that reaction time t=2 h, temperature θ=90 °C and dissipated Power P_d_i_s_s=46.27 W. At these conditions, this work shows the formation of nanocrystalline single-phase structure with particle size 10–25 nm. Also, ours magnetic measurements proved that the sonochemistry method has a great influence on enhancing the magnetic properties of the ferrite. - Highlights: • Coprecipitation experiments were carried out with ultrasound. • The spinel ferrite NiCuZn was perfectly synthesized by ultrasound. • The saturation magnetization and crystals size are found to be correlated as the dissipated power was varied.

  5. Proposed magnet system for EBT-P

    International Nuclear Information System (INIS)

    Ballou, J.K.; McManany, T.J.; Power, W.H.; Yeh, H.T.

    1979-01-01

    Since EBT-P, and other EBT devices, depends on having closed field lines for its successful operation, a very tight tolerance (on the order of 6 parts in 10 4 ) must be imposed on certain components of the field error. This is a global tolerance that influences the design of each magnet, its leads, the electrical bus, and the relative position of each magnet to its neighbors. This paper discusses the design, and field error analysis of the ORNL reference design for EBT-P

  6. Sb{sub 2}S{sub 3}:C/CdS p-n junction by laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Arato, A. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon (Mexico); Centro de Innovacion, Investigacion y Desarrollo en Ingenieria y Tecnologia-Universidad Autonoma de Nuevo Leon, Apodaca, Nuevo Leon (Mexico); Cardenas, E. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon (Mexico); Shaji, S. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon (Mexico); Centro de Innovacion, Investigacion y Desarrollo en Ingenieria y Tecnologia-Universidad Autonoma de Nuevo Leon, Apodaca, Nuevo Leon (Mexico); O' Brien, J.J.; Liu, J. [Center for Nanoscience, University of Missouri-St. Louis, One University Boulevard, St. Louis, Missouri-63121 (United States); Department of Chemistry and Biochemistry, University of Missouri-St. Louis, One University Boulevard, St. Louis, Missouri-63121 (United States); Castillo, G. Alan; Das Roy, T.K. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon (Mexico); Krishnan, B. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon (Mexico); Centro de Innovacion, Investigacion y Desarrollo en Ingenieria y Tecnologia-Universidad Autonoma de Nuevo Leon, Apodaca, Nuevo Leon (Mexico)], E-mail: bkrishnan@fime.uanl.mx

    2009-02-02

    In this paper, we report laser irradiated carbon doping of Sb{sub 2}S{sub 3} thin films and formation of a p-n junction photovoltaic structure using these films. A very thin carbon layer was evaporated on to chemical bath deposited Sb{sub 2}S{sub 3} thin films of approximately 0.5 {mu}m in thickness. Sb{sub 2}S{sub 3} thin films were prepared from a solution containing SbCl{sub 3} and Na{sub 2}S{sub 2}O{sub 3} at 27 deg. C for 5 h and the films obtained were highly resistive. These C/Sb{sub 2}S{sub 3} thin films were irradiated by an expanded laser beam of diameter approximately 0.5 cm (5 W power, 532 nm Verdi laser), for 2 min at ambient atmosphere. Morphology and composition of these films were analyzed. These films showed p-type conductivity due to carbon diffusion (Sb{sub 2} S{sub 3}:C) by the thermal energy generated by the absorption of laser radiation. In addition, these thin films were incorporated in a photovoltaic structure Ag/Sb{sub 2}S{sub 3}:C/CdS/ITO/Glass. For this, CdS thin film of 50 nm in thickness was deposited on a commercially available ITO coated glass substrate from a chemical bath containing CdCl{sub 2}, sodium citrate, NH{sub 4}OH and thiourea at 70 deg. C . On the CdS film, Sb{sub 2}S{sub 3}/C layers were deposited. This multilayer structure was subjected to the laser irradiation, C/Sb{sub 2}S{sub 3} side facing the beam. The p-n junction formed by p-Sb{sub 2}S{sub 3}:C and n-type CdS showed V{sub oc} = 500 mV and J{sub sc} = 0.5 mA/cm{sup 2} under illumination by a tungsten halogen lamp. This work opens up a new method to produce solar cell structures by laser assisted material processing.

  7. Irradiation Alters MMP-2/TIMP-2 System and Collagen Type IV Degradation in Brain

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Won Hee [School of Biomedical Engineering and Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia (United States); Warrington, Junie P.; Sonntag, William E. [Reynolds Oklahoma Center on Aging, Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma (United States); Lee, Yong Woo, E-mail: ywlee@vt.edu [School of Biomedical Engineering and Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia (United States); Department of Biomedical Sciences and Pathobiology, Virginia Polytechnic Institute and State University, Blacksburg, Virginia (United States)

    2012-04-01

    Purpose: Blood-brain barrier (BBB) disruption is one of the major consequences of radiation-induced normal tissue injury in the central nervous system. We examined the effects of whole-brain irradiation on matrix metalloproteinases (MMPs)/tissue inhibitors of metalloproteinases (TIMPs) and extracellular matrix (ECM) degradation in the brain. Methods and Materials: Animals received either whole-brain irradiation (a single dose of 10 Gy {gamma}-rays or a fractionated dose of 40 Gy {gamma}-rays, total) or sham-irradiation and were maintained for 4, 8, and 24 h following irradiation. mRNA expression levels of MMPs and TIMPs in the brain were analyzed by real-time reverse transcriptase-polymerase chain reaction (PCR). The functional activity of MMPs was measured by in situ zymography, and degradation of ECM was visualized by collagen type IV immunofluorescent staining. Results: A significant increase in mRNA expression levels of MMP-2, MMP-9, and TIMP-1 was observed in irradiated brains compared to that in sham-irradiated controls. In situ zymography revealed a strong gelatinolytic activity in the brain 24 h postirradiation, and the enhanced gelatinolytic activity mediated by irradiation was significantly attenuated in the presence of anti-MMP-2 antibody. A significant reduction in collagen type IV immunoreactivity was also detected in the brain at 24 h after irradiation. In contrast, the levels of collagen type IV were not significantly changed at 4 and 8 h after irradiation compared with the sham-irradiated controls. Conclusions: The present study demonstrates for the first time that radiation induces an imbalance between MMP-2 and TIMP-2 levels and suggests that degradation of collagen type IV, a major ECM component of BBB basement membrane, may have a role in the pathogenesis of brain injury.

  8. Irradiation Alters MMP-2/TIMP-2 System and Collagen Type IV Degradation in Brain

    International Nuclear Information System (INIS)

    Lee, Won Hee; Warrington, Junie P.; Sonntag, William E.; Lee, Yong Woo

    2012-01-01

    Purpose: Blood-brain barrier (BBB) disruption is one of the major consequences of radiation-induced normal tissue injury in the central nervous system. We examined the effects of whole-brain irradiation on matrix metalloproteinases (MMPs)/tissue inhibitors of metalloproteinases (TIMPs) and extracellular matrix (ECM) degradation in the brain. Methods and Materials: Animals received either whole-brain irradiation (a single dose of 10 Gy γ-rays or a fractionated dose of 40 Gy γ-rays, total) or sham-irradiation and were maintained for 4, 8, and 24 h following irradiation. mRNA expression levels of MMPs and TIMPs in the brain were analyzed by real-time reverse transcriptase-polymerase chain reaction (PCR). The functional activity of MMPs was measured by in situ zymography, and degradation of ECM was visualized by collagen type IV immunofluorescent staining. Results: A significant increase in mRNA expression levels of MMP-2, MMP-9, and TIMP-1 was observed in irradiated brains compared to that in sham-irradiated controls. In situ zymography revealed a strong gelatinolytic activity in the brain 24 h postirradiation, and the enhanced gelatinolytic activity mediated by irradiation was significantly attenuated in the presence of anti-MMP-2 antibody. A significant reduction in collagen type IV immunoreactivity was also detected in the brain at 24 h after irradiation. In contrast, the levels of collagen type IV were not significantly changed at 4 and 8 h after irradiation compared with the sham-irradiated controls. Conclusions: The present study demonstrates for the first time that radiation induces an imbalance between MMP-2 and TIMP-2 levels and suggests that degradation of collagen type IV, a major ECM component of BBB basement membrane, may have a role in the pathogenesis of brain injury.

  9. Magnetoplastic effect in irradiated NaCl and LiF crystals

    International Nuclear Information System (INIS)

    Al'shitz, V.I.; Darinskaya, E.V.; Kazakova, O.L.

    1997-01-01

    The effect of low x-ray irradiation doses (≅10 2 rad) on the magnetoplastic effect - the detachment of dislocations from paramagnetic centers under the action of an external magnetic field B - in alkali-halide crystals has been investigated. The measurements were performed on LiF crystals and three types of NaCl crystals, differing in impurity content. The dependence of the mean free path l of the dislocations on the rotational frequency ν of a sample in a magnetic field was especially sensitive to low irradiation doses. In unirradiated crystals this dependence is a single-step dependence and is characterized by a critical frequency ν c ∝B 2 above which the magnetoplastic effect is not observed. The frequency ν c depends only on the type of paramagnetic centers, and not on their density. Even the lowest irradiation dose employed ( c2 , that is insensitive to the irradiation dose, and that corresponds to the appearance of magnetically sensitive stoppers of a new type under irradiation. The initial critical frequency ν c1 , as a rule, also varies with the dose, reflecting the change in state of the impurity complexes (Ca in NaCl and Mg in LiF). Specifically, it is shown for NaCl(Ca) crystals that as the irradiation dose increases, the frequency ν c1 increases, gradually approaching the value ν c2 , so that by the time the dose is ≅300 rad, the dependence l(ν) once again becomes a single-step dependence, dropping sharply only for ν≥ν c2 . It is shown that the addition of a small number of Ni atoms to a NaCl crystal makes the Ca complexes radiation resistant, and the critical frequency ν c1 corresponding to them initially equals ν c2 for crystals with no Ni. The recombination kinetics of radiation defects in the case in which the samples are irradiated under a tungsten lamp was investigated. A possible physical model of the observed dependences is discussed

  10. Improvement of life time of SCC in type 304 stainless steel by ultrasound irradiation

    International Nuclear Information System (INIS)

    Tokiwai, Moriyasu; Kimura, Hideo

    1985-01-01

    It is well known that the susceptibility to stress corrosion cracking (SCC) is controled by compressive stress such as shot-peening treatment. In this study, the effects of ultrasound irradiation to type 304 stainless upon SCC were investigated. The main findings are as follows; (1) Ultrasound irradiation produces the high level compressive stress on the surface of metals. This compressive stress was induced by the cavitation phenomenon. (2) In U-bent specimen, the initial tensile stress was mitigated and converted to compressive stress by ultrasound irradiation. (3) Type 304 stainless steel was subjected to SCC test using sodium thyosulfate solution. It was definitely demonstrated that the ultrasound irradiation was effective for the mitigation of SCC life time. (4) Ultrasound irradiation time was one of the most important factors in irradiation conditions. (author)

  11. A structure development in electron-irradiated type Ia diamond

    International Nuclear Information System (INIS)

    Novikov, N.V.; Ositinskaya, T.D.; Tkach, V.N.

    1998-01-01

    A type Ia diamond crystal with nitrogen impurity in different forms was irradiated by 3.5 MeV electrons with increasing doses 5 centre dot 10 16 , 2 centre dot 10 17 , 4 centre dot 10 17 , 2 centre dot 10 18 e/cm 2 and investigated before and after each dose by positron annihilation, EPR, and optical spectroscopy. After irradiation with the highest dose, the effect of development of a visible defective structure of the crystal is revealed. A description of this effect and data of EPR and IR-measurements depending on irradiation doses are presented. First results of cathodoluminescence (CL) studies in the form CL-topograms and CL-spectra for difference zones of the crystal are also given

  12. Charge transport in non-irradiated and irradiated silicon detectors

    International Nuclear Information System (INIS)

    Leroy, C.; Roy, P.; Casse, G.L.; Glaser, M.; Grigoriev, E.; Lemeilleur, F.

    1999-01-01

    A model describing the transport of the charge carriers generated in n-type silicon detectors by ionizing particles is presented. In order to reproduce the experimental current pulse responses induced by α and β particles in non-irradiated and irradiated detectors up to fluences (PHI) much beyond the n to p-type inversion, an n-type region 15 μm deep is introduced on the p + side of the diode. This model also gives mobilities which decrease linearly up to fluences of around 5x10 13 particles/cm 2 and beyond, converging to saturation values of about 1000 and 450 cm 2 /V s for electrons and holes, respectively. The charge carrier lifetime degradation with increased fluence, due to trapping, is responsible for a predicted charge collection deficit for β particles and for α particles which is found to agree with direct CCE measurements. (author)

  13. Pure-type superconducting permanent-magnet undulator.

    Science.gov (United States)

    Tanaka, Takashi; Tsuru, Rieko; Kitamura, Hideo

    2005-07-01

    A novel synchrotron radiation source is proposed that utilizes bulk-type high-temperature superconductors (HTSCs) as permanent magnets (PMs) by in situ magnetization. Arrays of HTSC blocks magnetized by external magnetic fields are placed below and above the electron path instead of conventional PMs, generating a periodic magnetic field with an offset. Two methods are presented to magnetize the HTSCs and eliminate the field offset, enabling the HTSC arrays to work as a synchrotron radiation source. An analytical formula to calculate the peak field achieved in a device based on this scheme is derived in a two-dimensional form for comparison with synchrotron radiation sources using conventional PMs. Experiments were performed to demonstrate the principle of the proposed scheme and the results have been found to be very promising.

  14. Magnetic and fluorescent core-shell nanoparticles for ratiometric pH sensing

    International Nuclear Information System (INIS)

    Lapresta-Fernandez, Alejandro; Doussineau, Tristan; Moro, Artur J; Dutz, Silvio; Steiniger, Frank; Mohr, Gerhard J

    2011-01-01

    This paper describes the preparation of nanoparticles composed of a magnetic core surrounded by two successive silica shells embedding two fluorophores, showing uniform nanoparticle size (50-60 nm in diameter) and shape, which allow ratiometric pH measurements in the pH range 5-8. Uncoated iron oxide magnetic nanoparticles (∼10 nm in diameter) were formed by the coprecipitation reaction of ferrous and ferric salts. Then, they were added to a water-in-oil microemulsion where the hydrophilic silica shells were obtained through hydrolysis and condensation of tetraethoxyorthosilicate together with the corresponding silylated dye derivatives-a sulforhodamine was embedded in the inner silica shell and used as the reference dye while a pH-sensitive fluorescein was incorporated in the outer shell as the pH indicator. The magnetic nanoparticles were characterized using vibrating sample magnetometry, dynamic light scattering, transmission electron microscopy, x-ray diffraction and Fourier transform infrared spectroscopy. The relationship between the analytical parameter, that is, the ratio of fluorescence between the sensing and reference dyes versus the pH was adjusted to a sigmoidal fit using a Boltzmann type equation giving an apparent pK a value of 6.8. The fluorescence intensity of the reference dye did not change significantly (∼3.0%) on modifying the pH of the nanoparticle dispersion. Finally, the proposed method was statistically validated against a reference procedure using samples of water and physiological buffer with 2% of horse serum, indicating that there are no significant statistical differences at a 95% confidence level.

  15. Device for irradiation with electron and a magnetic lens for deviation of beams of charged particles, especially electrons

    International Nuclear Information System (INIS)

    Anderberg, B.

    1990-01-01

    An electron beam is sweeping aver the object while this is moved forward. In order to achieve a uniform irradiation and compensate for geometric errors, an additional magnetic lens is located immediately beneath the exposed area. The magnetic lens refract the electron beam in such a manner that the particle trajectories become parallel or slightly convergent after the lens. The lens consists of two parallel permanent bar magnets, preferably laminated magnets. (L.F.)

  16. Irradiation effects in superconductor oxides. Effets d'irradiation dans les oxydes supraconducteurs

    Energy Technology Data Exchange (ETDEWEB)

    Rullier-Albenque, F; Konczykowski, M [CEA-Ecole Polytechnique, 91 - Palaiseau (France). Lab. d' Etudes des Solides Irradies

    1993-01-01

    Several effects of irradiation on the 92 K - oxide superconductor YBa[sub 2]Cu[sub 3]O[sub 7] are reported. Whatever irradiation type, the critical temperature T[sub c] is found to decrease and the resistivity to increase. At sufficiently high damage levels, YBa[sub 2]Cu[sub 3]O[sub 7] is no longer superconducting and even displays a semiconducting-like behaviour. The alterations of superconducting properties are clearly related to oxygen defects - in the CuO[sub 2] planes or CuO chains... but we have shown experimentally that copper defects are also important. Magnetic properties of YBa[sub 2]Cu[sub 3]O[sub 7] in mixed state are also very sensitive to irradiation. By pinning the flux lines, irradiation defects can considerably increase the critical current density j[sub c]. At present, irradiations by highly energetic heavy ions (6 GeV Pb for instance), which produce cylindrical tubes of amorphous material (latent tracks) throughout the whole thickness of the samples, are probably the most efficient way to enhance j[sub c]. (Author). 18 refs., 7 figs.

  17. The quiescent and mitogen stimulated peripheral blood mononuclear cells after gamma irradiation and their P53, P21 and H2AX expression

    International Nuclear Information System (INIS)

    Vilasova, Z.; Vavrova, J.; Sinkorova, Z.; Tichy, A.; Oesterreicher, J.; Rezacova, M.; Zoelzer, F.

    2008-01-01

    The aim of this study was to compare reaction of quiescent and proliferating PHA (mitogenic lectin phytohemagglutinin)-stimulated human peripheral blood mononuclear cells (PBMCs) to γ-irradiation and analyze changes of proteins related to repair if DNA damage and apoptosis, such as γH2A.X, p53 and its phosphorylations on serine 15 and 392, and p21. Protein changes induced by radiation are different in quiescent and stimulated PBMCs. W e analyzed changes in proteins related to DNA damage repair and apoptosis using the western blot method in quiescent and stimulated PBMCs. Western blot technique can detect γH2A.X increase only at later times, when the phosphorylation of H2A.X is related to the onset of apoptosis (24-72 h after irradiation by the dose of 4 Gy). The level of H2A.X phosphorylation increased after stimulation of PBMC by PHA (72 h, 10 μg/ml) and as shown here it was detectable by western blot analysis. The increase in γH2A.X that we detected by western blot 4 h after irradiation of stimulated lymphocytes was dose dependent. It can be concluded that measurement of γH2A.X during the first hours after the irradiation is a good marker of the received dose of radiation. We compared the dynamics of p53 induction after irradiation by IR in both quiescent and stimulated lymphocytes. p53 increase was observed only in stimulated lymphocytes, as was p53 phosphorylation at serines-392 and -15. The increase in the amount of p53 was not dose-dependent 4 h after the irradiation. On the other hand, phosphorylation of p53 at serine-15 analyzed 4 h after the irradiation is dose-dependent over the studied dose range. Despite the fact that p53 was not detected in quiescent lymphocytes and a reaction to irradiation was not observed either, p21 levels increased after irradiation in both quiescent and stimulated lymphocytes in a dose-dependent manner. IR induces phosphorylation of p53 at both serines-15 and -392 in PHA stimulated human lymphocytes. However

  18. p-type ZnS:N nanowires: Low-temperature solvothermal doping and optoelectronic properties

    International Nuclear Information System (INIS)

    Wang, Ming-Zheng; Xie, Wei-Jie; Hu, Han; Yu, Yong-Qiang; Wu, Chun-Yan; Wang, Li; Luo, Lin-Bao

    2013-01-01

    Nitrogen doped p-type ZnS nanowires (NWs) were realized using thermal decomposition of triethylamine at a mild temperature. Field-effect transistors made from individual ZnS:N NWs revealed typical p-type conductivity behavior, with a hole mobility of 3.41 cm 2 V −1 s −1 and a hole concentration of 1.67 × 10 17  cm −3 , respectively. Further analysis found that the ZnS:N NW is sensitive to UV light irradiation with high responsivity, photoconductive gain, and good spectral selectivity. The totality of this study suggests that the solvothermal doping method is highly feasible to dope one dimensional semiconductor nanostructures for optoelectronic devices application

  19. Nano-patterning of perpendicular magnetic recording media by low-energy implantation of chemically reactive ions

    International Nuclear Information System (INIS)

    Martin-Gonzalez, M.S.; Briones, F.; Garcia-Martin, J.M.; Montserrat, J.; Vila, L.; Faini, G.; Testa, A.M.; Fiorani, D.; Rohrmann, H.

    2010-01-01

    Magnetic nano-patterning of perpendicular hard disk media with perpendicular anisotropy, but preserving disk surface planarity, is presented here. Reactive ion implantation is used to locally modify the chemical composition (hence the magnetization and magnetic anisotropy) of the Co/Pd multilayer in irradiated areas. The procedure involves low energy, chemically reactive ion irradiation through a resist mask. Among N, P and As ions, P are shown to be most adequate to obtain optimum bit density and topography flatness for industrial Co/Pd multilayer media. The effect of this ion contributes to isolate perpendicular bits by destroying both anisotropy and magnetic exchange in the irradiated areas. Low ion fluences are effective due to the stabilization of atomic displacement levels by the chemical effect of covalent impurities.

  20. Magnetic properties and magnetocaloric effect of MnFeP0.5Ge0.5-xSix compounds

    International Nuclear Information System (INIS)

    Song, L.; Wang, G.F.; Ou, Z.Q.; Haschaolu, O.; Tegus, O.; Brueck, E.; Buschow, K.H.J.

    2009-01-01

    We have studied the magnetic properties and magnetic-entropy changes of the MnFeP 0.5 Ge 0.5-x Si x compounds with x = 0.1, 0.2, 0.3, 0.4 and 0.45. X-ray diffraction shows that the compounds crystallize in the Fe 2 P-type hexagonal structure. The lattice parameter a and the Curie temperature decreases with increasing x. The maximal magnetic-entropy changes for x = 0.4 and 0.45 derived from the magnetization data are about 6.0 J/kg K and 5.8 J/kg K, respectively, for a field change from 0 to 1.5 T

  1. Low temperature fatigue crack propagation in neutron irradiated Type 316 steel and weld metal

    International Nuclear Information System (INIS)

    Lloyd, G.J.; Walls, J.D.; Gravenor, J.

    1981-02-01

    The fast cycling fatigue crack propagation characteristics of Type 316 steel and weld metal have been investigated at 380 0 C after irradiation to 1.72-1.92x10 20 n/cm 2 (E>1MeV) and 2.03x10 21 n/cm 2 (E>1MeV) at the same temperature. With mill-annealed Type 316 steel, modest decreases in the rates of crack propagation were observed for both dose levels considered, whereas for cold-worked Type 316 steel irradiation to 2.03x10 21 n/cm 2 (E>1MeV) caused increases in the rate of crack propagation. For Type 316 weld metal, increases in the rate of crack propagation were observed for both dose levels considered. The diverse influences of irradiation upon fatigue crack propagation in these materials are explained by considering a simple continuum mechanics model of crack propagation together with the results of control tensile experiments made on similarly irradiated materials. (author)

  2. Radiation damage and defect behavior in proton irradiated lithium-counterdoped n/sup +/p silicon solar cells

    International Nuclear Information System (INIS)

    Stupica, J.; Goradia, C.; Swartz, C.K.; Weinberg, I.

    1987-01-01

    Two lithium-counterdoped n/sup +/p silicon solar cells with different lithium concentrations were irradiated by 10 MeV protons. Cell performance was measured as a function of fluence, and it was found that the cell with the highest concentration of lithium had the higher radiation resistance. Deep level defects were studied using deep level transient spectroscopy which yielded two defects that were lithium related. Relating the defect energy levels obtained from this study under 10 MeV protons, with an earlier work using 1 MeV electron irradiations shows no correlation of the defect energy levels. There is one marked comparison though. The absence of the boron interstitial-oxygen interstitial defect. This consistency strengthens the belief that lithium interacts with oxygen to prevent the formation of the boron interstitial-oxygen interstitial defect. The present results indicate that, in general, addition of lithium in small amounts to the p-base of a boron doped silicon solar cell such that the base remains p-type, tends to increase the radiation resistance of the cell

  3. Nd: YAG laser irradiation effects on structural and magnetic properties of Ni1+xZrxFe2-2xO4 nanoparticles

    Science.gov (United States)

    Saraf, Tukaram S.; Kounsalye, Jitendra S.; Birajdar, Shankar D.; Shamkuwar, N. R.

    2018-05-01

    The effect of 112 mJ Nd: YAG laser irradiation on structural, morphological, infrared and magnetic properties of Ni1+xZrxFe2-2xO4 spinel ferrite nanoparticles has been systematically investigated in the present work. The sol-gel auto combustion synthesis method was successfully executed for the synthesis of the present system. All the samples were characterized by X-ray diffraction technique (XRD), scanning electron microscopy (SEM) and infrared spectroscopy (IR) technique. The magnetic properties of the present samples were measured by pulse field hysteresis loop technique. All the properties were measured for laser irradiated samples as well, to understand the effect of irradiation on the properties. The single-phase cubic spinel structure was confirmed by X-ray diffraction patterns of all samples and the disordered structure was observed for irradiated samples. The two principle absorption bands in IR spectra also confirm the formation of the spinel structure. Spherical and agglomerated morphology was observed for Zr4+ substituted nickel ferrite, whereas scratched morphology was observed for the irradiated samples. The grain size confirms the nanocrystalline nature, the crystallite size also evident the same. The magnetic parameters decreased after Zr4+ ion doping and strongly influenced by the irradiation.

  4. A structural study of effects of NiP seed layer on the magnetic properties of CoCrPt/Ti/NiP perpendicular magnetic films

    CERN Document Server

    Sun, C J; Wang, J P; Soo, E W; Noh, D Y; Je, J H; Hwu, Y K

    2003-01-01

    The CoCrPt/Ti/NiP films for perpendicular magnetic recording were studied using X-ray scattering and anomalous X-ray scattering. When the NiP seed layer was used, the long range order of the texture peak of the magnetic film decreased and less Co was associated with this Bragg order. The structural results were consistent with the observed increased coercivity and decreased magnetization due to the increased magnetic grain isolation caused by the presence of NiP seed layer.

  5. Post irradiation examination of type 316 stainless steels for in-pile Oarai water loop No.2 (OWL-2)

    International Nuclear Information System (INIS)

    Shibata, Akira; Kimura, Tadashi; Nagata, Hiroshi; Aoyama, Masashi; Kanno, Masaru; Ohmi, Masao

    2010-11-01

    The Oarai water loop No.2 (OWL-2) was installed in JMTR in 1972 for the purpose of irradiation experiments of fuel element and component material for light water reactors. Type 316 stainless steels (SSs) were used for tube material of OWL-2 in the reactor. But data of mechanical properties of highly irradiated Type 316 SSs has been insufficient since OWL-2 was installed. Therefore surveillance tests of type 316 SSs which were irradiated up to 3.4x10 25 n/m 2 in fast neutron fluence (>1 MeV) were performed. Meanwhile type 316 stainless steel (SS) is widely used in JMTR such as other irradiation apparatus and irradiation capsule, and additional data of type 316 SSs irradiated higher is required. Therefore post irradiation examinations of surveillance specimens made of type 316 SSs which were irradiated up to 1.0x10 26 n/m 2 in fast neutron fluence were performed and reported in this paper. In this result of surveillance tests of type 316 SSs irradiated up to 1.0x10 26 n/m 2 , tensile strength increase with increase of Neutron fluence and total elongation decreased with increase of Neutron fluence compared to unirradiated specimens and specimens irradiated up to 3.4x10 25 n/m 2 . This tendency has good agreement with results of 10 24 - 10 25 n/m 2 in fast neutron fluence. More than 37% in total elongation was confirmed in all test conditions. It was confirmed that type 316 SS irradiated up to 1.0x10 26 n/m 2 in fast neutron fluence has enough ductility as structure material. (author)

  6. Effect of swift heavy ion irradiation on structural and magnetic properties of GdFe{sub 1−x}Ni{sub x}O{sub 3} (x≤0.2) thin films

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Pawanpreet [Department of Physics, National Institute of Technology, Hamirpur, H.P. 177005 (India); Sharma, K.K., E-mail: kknitham@gmail.com [Department of Physics, National Institute of Technology, Hamirpur, H.P. 177005 (India); Pandit, Rabia [Department of Physics, National Institute of Technology, Hamirpur, H.P. 177005 (India); Choudhary, R.J. [UGC-DAE Consortium for Scientific Research at Indore, M.P. 452 001 (India); Kumar, Ravi [Centre for Material Science and Engineering, National Institute of Technology, Hamirpur, H.P 177005 (India)

    2016-01-15

    The present work reports the effect of Ni doping and 200 MeV Ag{sup 15+} ion irradiation on the structural and magnetic properties of GdFe{sub 1−x}Ni{sub x}O{sub 3} (x≤0.2) thin films grown on SrTiO{sub 3} (001) substrate by pulse laser deposition (PLD). From the XRD patterns ‘c-axis’ oriented growth in the pristine films is noticed, whereas after irradiation amorphization in the films is noticed. The atomic force microscopic (AFM) images reveal the increase in surface roughness with doping and irradiation as well. The irreversibility in the zero field cooled and field cooled magnetic curves indicates to the possibility of magnetic disorder in all the pristine as well as irradiated samples. Magnetization has been found to decrease with increasing Ni{sup 3+} ion substitution at room temperature whereas an enhancement in magnetization is noticed after ion irradiation for all the films. The disparity in the magnetic properties of pristine GdFe{sub 1−x}Ni{sub x}O{sub 3} (0.0≤x≤0.2) orthoferrites thin films can be correlated to the difference in hybridization in transition metal ion and O{sup 2−} ion orbitals. However, presence of strains caused by the columnar defects is responsible for the change in structural, morphological and magnetic properties in the irradiated samples. - Highlights: • ‘c-axis’ oriented GdFe{sub 1−x}Ni{sub x}O{sub 3} (x≤0.2) thin films grown on SrTiO{sub 3} substrate. • Thin films have been irradiated by 200 MeV Ag{sup 15+} ions. • Presence of columnar defects have been estimated using SRIM. • Magnetic disorder in all the film samples have been seen at lower temperatures. • Structural and magnetic characteristics altered with doping and ion irradiation.

  7. Neutron and gamma irradiation effects on organic insulating materials for fusion magnets

    International Nuclear Information System (INIS)

    Maurer, W.

    1985-10-01

    Available low-temperature neutron and gamma irradiation data for organic insulating materials are collected and compared with room temperature data. Only the most promising polymers in terms of mechanical strength for magnet insulation are taken into account. For characterization and comparison of different materials the 75% dose is used, i.e. the dose, where the mechanical strength is reduced by 25%, and 75% is retained. For room temperature special prepared polyimide and epoxy materials reinforced with glass fibre retained 75% of the mechanical strength up to a dose of 7x10 7 Gy. For 5 K irradiation the best epoxy material retained the 75% dose up to 1x10 7 Gy, the best polyimide material up to 1x10 8 Gy. (orig.) [de

  8. Specific features of recombination center formation under irradiation of dislocationless n-type Si

    International Nuclear Information System (INIS)

    Kolkovskij, I.I.; Lugakov, P.F.; Shusha, V.V.

    1989-01-01

    Peculiarities of recombination center formation during irradiation of non-dislocation n-Si, having so-called growth microdefects of different types - A,B,D, have been studied. Experimental results are obtained from the measurements in initial and irradiated by 60 Co γ-quanta (T irr ≤ 50 deg C) plates by the method of modulation of conductivity in point contact or by the drop in photoconductivity. On the basis of experimental data obtained the conclusion can be made that growth microdefects A-, B- and D-type do not produce any direct effect on the processes of accumulation of recombination and electrically active centers during irradiation. A decrease in the rate of E-center formation in crystals containing microdefects of A- and B-type observed in the experiment is related to the presence in their volume of impurity-defective accumulations of interstitial type presenting small inclusions of another phase surrounded by impurity atmosphere

  9. Controlled p-type to n-type conductivity transformation in NiO thin films by ultraviolet-laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Pranav; Dutta, Titas; Mal, Siddhartha; Narayan, Jagdish [Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27606 (United States)

    2012-01-01

    We report the systematic changes in structural, electrical, and optical properties of NiO thin films on c-sapphire introduced by nanosecond ultraviolet excimer laser pulses. Epitaxial nature of as deposited NiO was determined by x-ray diffraction phi scans and transmission electron microscopy (TEM) and it was established that NiO film growth takes place with twin domains on sapphire where two types of domains have 60 deg. in-plane rotation with respect to each other about the [111] growth direction. We determined that at pulsed laser energy density of 0.275 J/cm{sup 2}, NiO films exhibited conversion from p-type semiconducting to n-type conductive behavior with three orders of magnitude decrease in resistivity, while maintaining its cubic crystal structure and good epitaxial relationship. Our TEM and electron-energy-loss spectroscopy studies conclusively ruled out the presence of any Ni clustering or precipitation due to the laser treatment. The laser-induced n-type carrier transport and conductivity enhancement were shown to be reversible through subsequent thermal annealing in oxygen. This change in conductivity behavior was correlated with the nonequilibrium concentration of laser induced Ni{sup 0}-like defect states.

  10. Proton irradiation effects in silicon devices

    Energy Technology Data Exchange (ETDEWEB)

    Simoen, E; Vanhellemont, J; Alaerts, A [IMEC, Leuven (Belgium); and others

    1997-03-01

    Proton irradiation effects in silicon devices are studied for components fabricated in various substrates in order to reveal possible hardening effects. The degradation of p-n junction diodes increases in first order proportionally with the fluence, when submitted to 10 MeV proton irradiations in the range 5x10{sup 9} cm{sup -2} to 5x10{sup 11} cm{sup -2}. The damage coefficients for both p- and n-type Czochralski, Float-Zone and epitaxial wafers are reported. Charge-Coupled Devices fabricated in a 1.2 {mu}m CCD-CMOS technology are shown to be quite resistant to 59 MeV H{sup +} irradiations, irrespective of the substrate type. (author)

  11. Majority- and minority-carrier deep level traps in proton-irradiated n+/p-InGaP space solar cells

    International Nuclear Information System (INIS)

    Dharmarasu, Nethaji; Yamaguchi, Masafumi; Bourgoin, Jacques C.; Takamoto, Tatsuya; Ohshima, Takeshi; Itoh, Hisayoshi; Imaizumi, Mitsuru; Matsuda, Sumio

    2002-01-01

    We report the properties of observed defects in n + /p-InGaP solar cells created by irradiation of protons of different energies. Three majority (hole) and a minority-carrier traps, labeled respectively as HP1 (E v +0.90±0.05 eV), HP2 (E v +0.73±0.05 eV), H2 (E v +0.55 eV), and EP1 (E c -0.54 eV), were identified using deep level transient spectroscopy. All majority-carrier traps were found to act as recombination centers. While the H2 trap present in the proton-irradiated p-InGaP was found to anneal out by minority-carrier injection, the other traps were not

  12. Discovery of ferromagnetism with large magnetic anisotropy in ZrMnP and HfMnP

    Energy Technology Data Exchange (ETDEWEB)

    Lamichhane, Tej N.; Taufour, Valentin; Kaluarachchi, Udhara S.; Bud' ko, Sergey L.; Canfield, Paul C. [Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States); The Ames Laboratory, US Department of Energy, Iowa State University, Ames, Iowa 50011 (United States); Masters, Morgan W. [Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States); Parker, David S. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Thimmaiah, Srinivasa [The Ames Laboratory, US Department of Energy, Iowa State University, Ames, Iowa 50011 (United States)

    2016-08-29

    ZrMnP and HfMnP single crystals are grown by a self-flux growth technique, and structural as well as temperature dependent magnetic and transport properties are studied. Both compounds have an orthorhombic crystal structure. ZrMnP and HfMnP are ferromagnetic with Curie temperatures around 370 K and 320 K, respectively. The spontaneous magnetizations of ZrMnP and HfMnP are determined to be 1.9 μ{sub B}/f.u. and 2.1 μ{sub B}/f.u., respectively, at 50 K. The magnetocaloric effect of ZrMnP in terms of entropy change (ΔS) is estimated to be −6.7 kJ m{sup −3} K{sup −1} around 369 K. The easy axis of magnetization is [100] for both compounds, with a small anisotropy relative to the [010] axis. At 50 K, the anisotropy field along the [001] axis is ∼4.6 T for ZrMnP and ∼10 T for HfMnP. Such large magnetic anisotropy is remarkable considering the absence of rare-earth elements in these compounds. The first principle calculation correctly predicts the magnetization and hard axis orientation for both compounds, and predicts the experimental HfMnP anisotropy field within 25%. More importantly, our calculations suggest that the large magnetic anisotropy comes primarily from the Mn atoms, suggesting that similarly large anisotropies may be found in other 3d transition metal compounds.

  13. Discovery of ferromagnetism with large magnetic anisotropy in ZrMnP and HfMnP

    International Nuclear Information System (INIS)

    Lamichhane, Tej N.; Taufour, Valentin; Kaluarachchi, Udhara S.; Bud'ko, Sergey L.; Canfield, Paul C.; Masters, Morgan W.; Parker, David S.; Thimmaiah, Srinivasa

    2016-01-01

    ZrMnP and HfMnP single crystals are grown by a self-flux growth technique, and structural as well as temperature dependent magnetic and transport properties are studied. Both compounds have an orthorhombic crystal structure. ZrMnP and HfMnP are ferromagnetic with Curie temperatures around 370 K and 320 K, respectively. The spontaneous magnetizations of ZrMnP and HfMnP are determined to be 1.9 μ_B/f.u. and 2.1 μ_B/f.u., respectively, at 50 K. The magnetocaloric effect of ZrMnP in terms of entropy change (ΔS) is estimated to be −6.7 kJ m"−"3 K"−"1 around 369 K. The easy axis of magnetization is [100] for both compounds, with a small anisotropy relative to the [010] axis. At 50 K, the anisotropy field along the [001] axis is ∼4.6 T for ZrMnP and ∼10 T for HfMnP. Such large magnetic anisotropy is remarkable considering the absence of rare-earth elements in these compounds. The first principle calculation correctly predicts the magnetization and hard axis orientation for both compounds, and predicts the experimental HfMnP anisotropy field within 25%. More importantly, our calculations suggest that the large magnetic anisotropy comes primarily from the Mn atoms, suggesting that similarly large anisotropies may be found in other 3d transition metal compounds.

  14. Types of repair in radiosensitive organs of mice subjected to continuous γ-irradiation

    International Nuclear Information System (INIS)

    Li Yuanmin; Hu Fenghua; Gao Yabin

    1990-01-01

    LACA mice were whole-body irradiated with 1 Gy continuous γ-irradiation for 22 hours daily. Animals were divided into groups according to different cumulative doses of 10, 15, 20, 25 and 30 Gy, and were sacrificed at different intervals after the termination of irradiation when the above doses were reached. Radiosensitive organs were stduied by determination of quantitative indices and microscopic examination of histopathological sections. Three types of repair of radiation damages were found in radiosensitive organs, i.e. (1) full repair during irradiation in small intestines, (2) repair only after cessation of irradiation in hemopoietic and lymphoid tissues, and (3) continuing damage even after cessation of irradiation in testes

  15. Effect of RNAi p21 gene on uncoupling of EL-4 cells induced by X-irradiation

    International Nuclear Information System (INIS)

    Ju Guizhi; Yan Fengqin; Fu Shibo; Shen Bo; Sun Shilong; Yang Ying; Li Pengwu

    2008-01-01

    Objective: To investigate the effect of RNAi p21 gene on uncoupling of EL-4 cells induced by X-irradiation. Methods: Construction of RNAi p21 plasmid of pSileneer3.1-H1 neo-p21 was performed. Lipofectamine transfection assay was used to transfer the p21siBNA into EL-4 cells. Fluorescent staining and flow cytometry (FCM) analysis were employed for measurement of protein expression. Fluorescent staining of propidium iodide (PI) and FCM were used for measurement of potyploid cells. Results: In dose-effect experiment it was found that the expression of P21 protein of EL-4 cells increased significantly 24 h after X- irradiation with different doses compared with sham-inadiated control. In time course experiment it was found that the expression of P21 protein of EL-4 cells increased significantly at 8 h to 72 h after 4.0 Gy X-irradiation compared with sham-irradiated control. The results showed that the number of polyploid cells in EL-4 cells was not changed markedly after X-irradiation with doses of 0.5-6.0 Gy. After RNA interference with p21 gene, the expression of P21 protein of EL-4 cells decreased significantly 24 h and 48 h after 4.0 Gy X-irradiation in transfection of plasmid of pSilencer3.1-H1 neo-p21 compared with transfection of plasmid of pSilencer3.1-H1 nco control. And at the same time, the number of polyploid cells in EL-4 cells was increased significantly in transfection of plasmid of pSilencer3.1-H1 neo-p21 compared with transfection of plasmid of pSilencer3.1-H1 nco control. Conclusions: Uncoupling could be induced by X-irradiation in EL-4 cells following BNAi p21 gene, suggesting that P21 protein may play an important role in uncoupling induced by X-rays. (authors)

  16. P53-dependent ceramide generation in response ro ionizing irradiation is caspase-dependent

    International Nuclear Information System (INIS)

    Dbaibo, G.; El-Assaad, W.

    2000-01-01

    Full text.We have previously reported that p53-dependent apoptosis is accompanied by ceramide accumulation. Lack of p53 prevents ceramide accumulation in response to induces such as ionizing irradiation. The mechanisms of ceramide accumulation have not been explored. P53 has been reported to function by inducing the death receptors Fas and DR5 both of which function by initiating a caspase cascade that results in apoptosis. We decided to examine the role of caspases in the elevation of cellular ceramide levels. We treated Molt-4 cells with 5Gy of ionizing irradiation and examined the effects of co-treatment with the general caspase inhibitor z-VAD-fmk at concentration of 50 and 100μM. We found that z-VAD blocked apoptosis induced by irradiation without interfering with p53 accumulation indicating that it was not functioning upstream of p53. However, z-VAD treatment resulted in a significant decrease in ceramide accumulation. Additionally, z-VAD partially blocked the loss of glutathione in response to irradiation. This was important since glutathione has been described as an inhibitor of neutral sphindomyelinase, a major source of cellular ceramide via sphingomyelin hydrolysis. These studies indicate that p53 induces ceramide accumulation in a caspase-dependent manner and that the regulation of cellular glutathione by caspases may be a mechanism by which they regulate ceramide accumulation

  17. Radiation enhanced reactivation of irradiated human adenovirus type 2 in human cells

    International Nuclear Information System (INIS)

    Jeeves, W.P.

    1981-04-01

    Radiation-enhanced reactivation (ER) of a radiation-damaged mammalian virus is the term given to the observation that the survival of irradiated virus can be enhanced by irradiation of an appropriate host cell prior to infection. In this work, both UV-enhanced reactivation (UVER) and gamma-ray-enhanced reactivation (γRER) of irradiated human adenovirus type 2 (AD 2) were studied in a variety of normal and DNA repair-deficient human fibroblast host cell strains. In order to examine the lesion specificity of ER in human cells, experiments were performed using UV-irradiated and γ-irradiated virus. The investigation was carried out using a sensitive technique of indirect immunofluorescence, according to which irradiated and unirradiated cell cultures were infected with irradiated or unirradiated AD 2 and were subsequently examined for the presence of viral structural antigens ('V' Ag) at a fixed time after infection

  18. Study of ln s Physics in $\\bar{p}p$ Interactions at the Split Field Magnet

    CERN Multimedia

    2002-01-01

    This experiment uses the Split Field Magnet detector to investigate the low p^t, ``ln~s'', type of interactions that dominate the @*p cross-section. Systematic comparisons will be made to pp interactions. \\\\ \\\\ Specific areas to be studied include elastic scattering in the regions 0.05 $<$ !t! $<$ 0.8 GeV|2 and 0.8 $<$ !t! $<$ 4.0 GeV|2, and the use of a minimum bias trigger to study topological cross-sections, inclusive spectra, and two-body correlations. Some specialized triggers, run simultaneously with the high t elastic scattering trigger, are being studied. Examples are a trigger requiring Cerenkov identification in a limited region of phase space, and a trigger to select diffractively produced events.

  19. Electrical performance of the InGaP solar cell irradiated with low energy electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Okuno, Yasuki; Okuda, Shuichi; Kojima, Takeo; Oka, Takashi [Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai City, Osaka (Japan); Kawakita, Shirou; Imaizumi, Mitsuru; Kusawake, Hiroaki [Japan Aerospace Exploration Agency (JAXA), 2-1-1 Sengen, Tsukuba, Ibaraki (Japan)

    2015-06-15

    The investigation of the radiation degradation characteristics of InGaP space solar cells is important. In order to understand the mechanism of the degradation by radiation the samples of the InGaP solar cell were irradiated in vacuum and at ambient temperature with electron beams from a Cockcroft-Walton type accelerator at Osaka Prefecture University. The threshold energies for recoil were obtained by theoretical calculation. The energies and the fluences of the electron beams were from 60 to 400 keV and from 3 x 10{sup 14} to 3 x 10{sup 16} cm{sup -2}, respectively. The light-current-voltage measurements were performed. The degradation of Isc caused by the defects related to the phosphorus atoms was observed and the degradation was suppressed by irradiation at an energy higher than the threshold energy for recoiling Indium atoms. At an energy of 60 keV, where the recoil does not occur, the V{sub oc} was degraded. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. CLINICAL APPLICABILITY OF HUMAN IN-VIVO LOCALIZED P-31 MAGNETIC-RESONANCE SPECTROSCOPY OF BONE AND SOFT-TISSUE TUMORS

    NARCIS (Netherlands)

    HOEKSTRA, HJ; BOEVE, WJ; KAMMAN, RL; MOOYAART, EL

    1994-01-01

    Background: Magnetic resonance imaging (MRI) is of restricted value for the in vivo characterization of tumor types. The applicability of phosphorus-31 (P-31) magnetic resonance spectroscopy (MRS) in the diagnosis of bone and soft tissue tumors is unknown. Methods: A total of 191 consecutive

  1. Pressure-induced magnetic transition in CeP

    International Nuclear Information System (INIS)

    Naka, T.; Matsumoto, T.; Mori, N.; Okayama, Y.; Haga, Y.; Suzuki, T.

    1997-01-01

    Pressure dependence of magnetization in CeP is investigated up to 2 GPa. Multi-step transitions are induced by pressure. An antiferromagnetic transition at T N =11 K below 0.1 GPa develops into two (magnetic) transitions at T L and T H in the region of 0.1 L , T H and T d above 1.3 GPa. For decreasing temperature an abrupt increase of magnetization, M(T), has been observed below T H and a round maximum of magnetization appears at T L for P≥0.4 GPa. Above 1.3 GPa, an anomalous decrease of M(T) begins at T d =10 K. Using previously reported 31 P-NMR shift data it is shown that the pressure dependence of a characteristic temperature, which is proportional to the crystal field splitting in the paramagnetic temperature region, decreases rapidly with increasing pressure. (orig.)

  2. A type of 2D magnetic equivalent circuit framework of permanent magnet for magnetic system in AEMR

    Directory of Open Access Journals (Sweden)

    Huimin Liang

    2015-02-01

    Full Text Available Modeling of permanent magnet (PM is very important in the process of electromagnetic system calculation of aerospace electromagnetic relay (AEMR. In traditional analytical calculation, PM is often equivalent to a lumped parameter model of one magnetic resistance and one magnetic potential, but great error is often caused for the inner differences of PM; based on the conception of flux tube, a type of 2D magnetic equivalent circuit framework of permanent magnet model (2D MECF is established; the element is defined, the relationship between elements is deduced, and solution procedure as well as verification condition of this model is given; by a case study of the electromagnetic system of a certain type of AEMR, the electromagnetic system calculation model is established based on 2D MECF and the attractive force at different rotation angles is calculated; the proposed method is compared with the traditional lumped parameter model and finite element method (FEM; for some types of electromagnetic systems with symmetrical structure, 2D MECF proves to be of acceptable accuracy and high calculation speed which fit the requirement of robust design for AEMR.

  3. P-type sp3-bonded BN/n-type Si heterodiode solar cell fabricated by laser-plasma synchronous CVD method

    International Nuclear Information System (INIS)

    Komatsu, Shojiro; Nagata, Takahiro; Chikyo, Toyohiro; Sato, Yuhei; Watanabe, Takayuki; Hirano, Daisuke; Takizawa, Takeo; Nakamura, Katsumitsu; Hashimoto, Takuya; Nakamura, Takuya; Koga, Kazunori; Shiratani, Masaharu; Yamamoto, Atsushi

    2009-01-01

    A heterojunction of p-type sp 3 -bonded boron nitride (BN) and n-type Si fabricated by laser-plasma synchronous chemical vapour deposition (CVD) showed excellent rectifying properties and proved to work as a solar cell with photovoltaic conversion efficiency of 1.76%. The BN film was deposited on an n-type Si (1 0 0) substrate by plasma CVD from B 2 H 6 + NH 3 + Ar while doping of Si into the BN film was induced by the simultaneous irradiation of an intense excimer laser with a pulse power of 490 mJ cm -2 , at a wavelength of 193 nm and at a repetition rate of 20 Hz. The source of dopant Si was supposed to be the Si substrate ablated at the initial stage of the film growth. The laser enhanced the doping (and/or diffusion) of Si into BN as well as the growth of sp 3 -bonded BN simultaneously in this method. P-type conduction of BN films was determined by the hot (thermoelectric) probe method. The BN/Si heterodiode with an essentially transparent p-type BN as a front layer is supposed to efficiently absorb light reaching the active region so as to potentially result in high efficiency.

  4. Genomic alterations during p53-dependent apoptosis induced by γ-irradiation of Molt-4 leukemia cells.

    Directory of Open Access Journals (Sweden)

    Rouba Hage-Sleiman

    Full Text Available Molt-4 leukemia cells undergo p53-dependent apoptosis accompanied by accumulation of de novo ceramide after 14 hours of γ-irradiation. In order to identify the potential mediators involved in ceramide accumulation and the cell death response, differentially expressed genes were identified by Affymetrix Microarray Analysis. Molt-4-LXSN cells, expressing wild type p53, and p53-deficient Molt-4-E6 cells were irradiated and harvested at 3 and 8 hours post-irradiation. Human genome U133 plus 2.0 array containing >47,000 transcripts was used for gene expression profiling. From over 10,000 probes, 281 and 12 probes were differentially expressed in Molt-4-LXSN and Molt-4-E6 cells, respectively. Data analysis revealed 63 (upregulated and 20 (downregulated genes (>2 fold in Molt-4-LXSN at 3 hours and 140 (upregulated and 21 (downregulated at 8 hours post-irradiation. In Molt-4-E6 cells, 5 (upregulated genes each were found at 3 hours and 8 hours, respectively. In Molt-4-LXSN cells, a significant fraction of the genes with altered expression at 3 hours were found to be involved in apoptosis signaling pathway (BCL2L11, p53 pathway (PMAIP1, CDKN1A and FAS and oxidative stress response (FDXR, CROT and JUN. Similarly, at 8 hours the genes with altered expression were involved in the apoptosis signaling pathway (BAX, BIK and JUN, p53 pathway (BAX, CDKN1A and FAS, oxidative stress response (FDXR and CROT and p53 pathway feedback loops 2 (MDM2 and CDKN1A. A global molecular and biological interaction map analysis showed an association of these altered genes with apoptosis, senescence, DNA damage, oxidative stress, cell cycle arrest and caspase activation. In a targeted study, activation of apoptosis correlated with changes in gene expression of some of the above genes and revealed sequential activation of both intrinsic and extrinsic apoptotic pathways that precede ceramide accumulation and subsequent execution of apoptosis. One or more of these altered genes

  5. Annealing effects on resistivity and Hall coefficient of neutron irradiated silicon

    International Nuclear Information System (INIS)

    Biggeri, U.

    1995-01-01

    High Temperature Annealing (HTA) treatment has been carried out on fast-neutron irradiated silicon samples with temperatures up to 300 C. Fluences of irradiation up to 1x10 14 n/cm 2 were used. Before annealing, samples irradiated with fluences higher than 1x10 13 n/cm 2 suffered the type conductivity inversion from n-type to p-type. The changes in the resisitivity and Hall coefficient during each annealing step have been measured by Hall effect analysis. Results indicate the possible creation of acceptors for low temperature annealing up to 150 C and the phosphorous release by E centres at annealing temperatures among 150 C and 200 C. Heating samples up to 300 C allows the recovering of the sample resistivity to its value before irradiation, with the peculiarity that bulks inverted to p-type after irradiation does not come back to n-type after annealing. (orig.)

  6. The effects of three types of macrophages culture supernatant on CFU-GM in irradiated mice

    International Nuclear Information System (INIS)

    Quan Hongxun; Fu Li; Zhao Fengchen; Han Fen

    2008-01-01

    Objective: To study the effects of peritional macrophyge(PM), alveolar macrophage (AM), and Kupffer cell (KC) on colony forming unite granulacyte/macrophage (CFU -GM) in irradiated mice. Methods: Using techniques of hemopoietic progenitors in vitro, the authors studied the effects of three types of macrophages culture supernatant on CFU - GM. Results: It is shown that three types of macrophages culture supernatant may stimulate proliferation and differentiation of CFU-GM in irradiated mice, and KC is the best one in comparison to others. Conclusion: three types of macrophages culture supernatant may protect CFU-GM irradiated mice with KC being the best method. (authors)

  7. Safety analysis report of the irradiation test of Type-B bundle

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Choong Sung; Lim, I. C.; Lee, B. C.; Ryu, J. S.; Kim, H. R

    2000-06-01

    The HANARO fuel, U{sub 3}Si-A1, has been developed by AECL and tested in NRU reactor. In the course of the fuel qualification tests, only one case was performed under the higher power condition than maximum linear power which was expected in the design stage. The Korea regulatory body, KINS imposed that HANARO shall be operated at the power level less than 24MW which is 80% of the design full power until HANARO shows the repetitive performance of the fuel at the power condition abov e 112.8KW/m. To resolve this imposition, KAERI designed two types of special test bundles: two non-instrumented(Type-A) and one instrumented(Type-B) test bundles. Two Type-A bundles were irradiated in HANARO: one of them has finished PIE and the other is under PIE. Type-B bundle was loaded in the core during 1.32 day at 1996, but outstanding FIV(flow induced vibration) was observed at the pool top because of long guide tube attached to the top of the bundle. The successful installation of the chimney fastener to fix the guide tube resulted in conducting the irradiation test of Type-B bundle again. The test will start at mid- July, 2000. In order to safely do the Type-B irradiation test, the safety analysis for the nuclear, mechanical and thermal-hydraulic aspects was performed. The reactivity worth and the maximum 1 near power predicted by VENTURE are 6.3mk/k and 121.6kW/m, respectively. Thermal margins for normal and transient conditions using MATRA-h, are assessed to satisfy the safety criteria.

  8. X-ray diffraction on MnFeP0.46As0.54 in a magnetic field

    International Nuclear Information System (INIS)

    Tegus, O.; Koyama, K.; Her, J.L.; Watanabe, K.; Brueck, E.; Buschow, K.H.J.; Boer, F.R. de

    2007-01-01

    We have performed powder X-ray-diffraction measurements on MnFeP 0.46 As 0.54 in fields up to 5T in the temperature range 8-310K. The compound which has the hexagonal Fe 2 P type of structure shows a field-induced isostructural phase transition. We found that the cell volume decreases slightly and continuously with increasing magnetic field, although the lattice parameter ratio c/a drastically changes. A tentative analysis of the dependence of the lattice parameters on the magnetization has been carried out using the extended Bean-Rodbell model

  9. Posterior magnetic effect on the pure and doped Fe-Ni alloy under neutron irradiation

    International Nuclear Information System (INIS)

    Ferreira, Iris

    1974-01-01

    Polycrystalline specimens of unirradiated and neutron irradiated Fe-Ni alloys have been studied in the temperature range RT - 500 deg C. The study was carried out in pure (50-50) as well as in Si, A1, Cr and Mo doped samples. Initial magnetic permeability was measured in unirradiated (virgin)and in neutron irradiated samples, during isochronal and linear thermal treatments. The main results are: a magnetic After Effect (MAE) is detected in the temperature range 370 deg C - Tc, where Tc is the Curie Temperature. In this range an activation energy of 3.2 ± 0.2 eV was determined for the Cr doped Fe-Ni alloy (impurity content: 0.1%); measurements made in the irradiated samples, during a linear temperature treatment, show the existence of several MAE zones in the temperature range RT - Tc. The isochronal annealing experiments show that these MAE zones are accompanied by a decrease in the room temperature value of the magnetic permeability, for zones between RT and a certain temperature T 1 . Above this range there is a steep increase in the room temperature permeability. Activation energies were determined for pure and Mo-doped (0.1%) samples for the first MAE zone (50 deg C - 120 deg C). The values obtained 1.25 - 0.08 eV and 1.42 ± 0.09 eV, respectively; the impurity - doped samples show a different behaviour relative to the pure ones: samples with low impurity content (0.1% and 0.5% of Si, Al or Mo) present an enhancement in the amplitude and also an overlapping of the diffusion stages. On the other hand, samples with higher impurity content (2 and 4% of Mo) show a decrease in these amplitudes. (author)

  10. Study on a magnetic spiral-type wireless capsule endoscope controlled by rotational external permanent magnet

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Bo, E-mail: yebo@hubu.edu.cn [School of Mechanical Science & Engineering, Huazhong University of Science & Technology, Wuhan 430074 (China); School of Computer Science and Information Engineering, HuBei University, Wuhan 430062 (China); Zhang, Wei [Department of Mechanical Engineering, Hubei University of Automotive Technology, Shiyan 442002 (China); Sun, Zhen-jun [School of Mechanical Science & Engineering, Huazhong University of Science & Technology, Wuhan 430074 (China); Guo, Lin [School of Computer Science and Information Engineering, HuBei University, Wuhan 430062 (China); Deng, Chao [School of Mechanical Science & Engineering, Huazhong University of Science & Technology, Wuhan 430074 (China); Chen, Ya-qi [Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030 (China); Zhang, Hong-hai [School of Mechanical Science & Engineering, Huazhong University of Science & Technology, Wuhan 430074 (China); Liu, Sheng [School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072 (China)

    2015-12-01

    In this paper, the authors propose rotating an external permanent magnet (EPM) to manipulate the synchronous rotation of a magnetic spiral-type wireless capsule endoscope (WCE), and the synchronous rotation of the WCE is converted to its translational motion in intestinal tract. In order to preliminarily verify the feasibility of this method, a handheld actuator (HA) controlled by micro controller unit, a magnetic spiral-type WCE and a bracket were fabricated, theoretical analysis and simulations about the control distance of this method were performed, and in ex-vivo tests were examined in porcine small intestine to verify the control distance and control performances of this method. It was demonstrated that this method showed good performances in controlling the translational motion of the magnetic spiral-type WCE, and this method has great potential to be used in clinical application. - Highlights: • A new magnetic control method for spiral-type wireless capsule endoscope is proposed. • Wireless capsule endoscope rotates synchronously with external permanent magnet. • The method controls the wireless capsule endoscope well in porcine small intestine. • Long control distance makes the method may be used in future medical application. • Experimental setup has great advantages: high cost performance and easy operation.

  11. Investigation of cryogenic irradiation influence on mechanical and physical properties of ITER magnetic system insulation materials

    International Nuclear Information System (INIS)

    Kozlov, A.V.; Scherbacov, E.N.; Dudchenko, N.A.; Shihalev, V.S.; Bedin, V.V.; Paltusov, N.A.; Korsunskiy, V.E.

    1998-01-01

    A set of methods of cryogenic irradiation influence test on mechanical and physical properties of insulation of ITER magnetic system are presented in this paper. Investigations are carried out without intermediate warming up of samples. A Russian insulating composite material was irradiated in the IVV-2M reactor. The ratio of energy absorbed by insulation materials from neutron irradiation to that from gamma irradiation can be varied from ∝(25:75)% to ∝(50:50)% in the reactor. The test results on the thermal expansion, thermal conductivity and gas evolution of the above material are presented. It was shown, that cryogenic irradiation up to the fluence ∝2 x 10 22 n/m 2 (E ≥ 0.1 MeV) leads to 0.27% linear size changes along layers of fiber-glass, the thermal conductivity coefficient is decreased on 15% at 100 k in perpendicular direction to fiber-glass plane, and thermal coefficient of linear expansion (TCLE) has anomalous temperature dependence. (orig.)

  12. Fatigue behavior of type 316 stainless steel following neutron irradiation inducing helium

    International Nuclear Information System (INIS)

    Grossbeck, M.L.; Liu, K.C.

    1980-01-01

    Since a tokamak fusion reactor operates in a cyclic mode, thermal stresses will result in fatigue in structural components, especially the first wall and blanket. Type 316 stainless steel in the 20% cold-worked condition has been irradiated in the HFIR in order to introduce helium as well as displacement damage. A miniature hourglass specimen was developed for the reactor irradiations and subsequent fully reversed low cycle fatigue testing. For material irradiated and tested at 430 0 C in vacuum to a damage level of 7 to 15 dpa and containing 200 to 1000 appm He, a reduction in life by a factor of 3 to 10 was observed. An attempt was made to predict irradiated fatigue life by fitting data from irradiated material to a power law equation similar to the universal slopes equation and using ductility ratios from tensile tests to modify the equation for irradiated material

  13. Effect of high fluence neutron irradiation on transport properties of thermoelectrics

    Science.gov (United States)

    Wang, H.; Leonard, K. J.

    2017-07-01

    Thermoelectric materials were subjected to high fluence neutron irradiation in order to understand the effect of radiation damage on transport properties. This study is relevant to the NASA Radioisotope Thermoelectric Generator (RTG) program in which thermoelectric elements are exposed to radiation over a long period of time in space missions. Selected n-type and p-type bismuth telluride materials were irradiated at the High Flux Isotope Reactor with a neutron fluence of 1.3 × 1018 n/cm2 (E > 0.1 MeV). The increase in the Seebeck coefficient in the n-type material was partially off-set by an increase in electrical resistivity, making the power factor higher at lower temperatures. For the p-type materials, although the Seebeck coefficient was not affected by irradiation, electrical resistivity decreased slightly. The figure of merit, zT, showed a clear drop in the 300-400 K range for the p-type material and an increase for the n-type material. Considering that the p-type and n-type materials are connected in series in a module, the overall irradiation damages at the device level were limited. These results, at neutron fluences exceeding a typical space mission, are significant to ensure that the radiation damage to thermoelectrics does not affect the performance of RTGs.

  14. 1.0 MeV irradiation of OHMIC, MS, MIS contacts to InP

    International Nuclear Information System (INIS)

    Warren, C.E.; Wagner, B.F.; Anderson, W.A.

    1986-01-01

    The radiation effects of 1.0 MeV electrons with a dose of 10/sup 15/cm/sup -2/ to MS and MIS Schottky diodes on InP have been compared to the radiation effects of MIS diodes on GaAs and Si. The radiation effects to ohmic contacts were also investigated. The metal for the diodes on the InP was gold. Au/Ti/Al was used for the GaAs diodes and Cr for the silicon diodes. Oxide layers on InP were grown by anodization in 0.1 N KOH. Oxides to GaAs and Si were grown thermally. Ohmic contacts to InP were formed using AuGe/Ni and AuSn alloys, followed by annealing in N/sub 2//H/sub 2/ (85%/15%). Metal Semiconductor diodes on InP were found to be at least sensitive to the irradiation. The InP MS and MIS diodes showed only small changes in the current voltage (I-V) characteristic, whereas the GaAs and Si devices showed a decrease in reverse current after irradiation. The ohmic contact resistance was increased by a factor of 2 to 5 after irradiation

  15. Tuning microstructure and magnetic properties of electrodeposited CoNiP films by high magnetic field annealing

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Chun; Wang, Kai [Key Laboratory of Electromagnetic Processing of Materials (Ministry of Education), Northeastern University, Shenyang 110819 (China); Li, Donggang, E-mail: lidonggang@smm.neu.edu.cn [School of Metallurgy, Northeastern University, Shenyang 110819 (China); Lou, Changsheng [School of Materials Science and Engineering, Shenyang Ligong University, Shenyang 110159 (China); Zhao, Yue; Gao, Yang [Key Laboratory of Electromagnetic Processing of Materials (Ministry of Education), Northeastern University, Shenyang 110819 (China); Wang, Qiang, E-mail: wangq@mail.neu.edu.cn [Key Laboratory of Electromagnetic Processing of Materials (Ministry of Education), Northeastern University, Shenyang 110819 (China)

    2016-10-15

    A high magnetic field (up to 12 T) has been used to anneal 2.6-µm-thick Co{sub 50}Ni{sub 40}P{sub 10} films formed by pulse electrodeposition. The effects of high magnetic field annealing on the microstructure and magnetic properties of CoNiP thin films have been investigated. It was found that a high magnetic field accelerated a phase transformation from fcc to hcp and enhanced the preferred hcp-(002) orientation during annealing. Compared with the films annealed without a magnetic field, annealing at 12 T decreased the surface particle size, roughness, and coercivity, but increased the saturation magnetization and remanent magnetization of CoNiP films. The out-of-plane coercivity was higher than that the in-plane for the as-deposited films. After annealing without a magnetic field, the out-of-plane coercivity was equal to that of the in-plane. However, the out-of-plane coercivity was higher than that of the in-plane when annealing at 12 T. These results indicate that high magnetic field annealing is an effective method for tuning the microstructure and magnetic properties of thin films. - Highlights: • High magnetic field annealing accelerated phase transformation from γ to ε. • High magnetic field annealing enhanced preferred hcp-(002) orientation. • High magnetic field annealing decreased particle size, roughness and coercivity. • High magnetic field annealing increased the saturation and remanent magnetization.

  16. Magnetic properties and magnetocaloric effects in Mn1.2Fe0.8P1-xGex compounds

    International Nuclear Information System (INIS)

    Ou, Z Q; Wang, G F; Lin Song; Tegus, O; Brueck, E; Buschow, K H J

    2006-01-01

    We have studied the magnetic properties and magnetocaloric effects in the Mn 1.2 Fe 0.8 P 1-x Ge x compounds with x = 0.2, 0.22, 0.3, 0.4 and 0.5. X-ray diffraction patterns show that the Mn 1.2 Fe 0.8 P 1-x Ge x compounds crystallize in the hexagonal Fe 2 P-type crystal structure. The magnetic moments of the Mn 1.2 Fe 0.8 P 1-x Ge x compounds measured at 5 K and 5 T increase with increasing Ge content. The Curie temperature increases strongly and the magnetic entropy change has a maximum around 233 K for the compound with x = 0.22, which is about 19 and 31 J kg -1 K -1 for a field change of 2 and 5 T, respectively

  17. First results on the charge collection properties of segmented detectors made with p-type bulk silicon

    International Nuclear Information System (INIS)

    Casse, G.; Allport, P.P.; Bowcock, T.J.V.; Greenall, A.; Hanlon, M.; Jackson, J.N.

    2002-01-01

    Radiation damage of n-type bulk detectors introduces stable defects acting as effective p-type doping and leads to the change of the conductivity type of the silicon substrate (type inversion) after a fluence of a few times 10 13 protons cm -2 . The diode junction after inversion migrates from the original side to the back plane of the detector. The migration of the junction can be prevented using silicon detectors with p-type substrates. Furthermore, the use of n-side readout gives higher charge collection efficiency for segmented devices operated below the full depletion voltage. Large area (∼6.4x6.4 cm 2 ) capacitively coupled 80 μm pitch detectors using polysilicon bias resistors have been fabricated on p-type substrates (n-in-p diode structure). These detectors have been irradiated with 24 GeV/c protons to an integrated fluence of 3x10 14 cm -2 and kept for 7 days at 25 deg. C to reach the broad minimum of the annealing curve. Results are presented on the comparison of their charge collection properties with detectors using p-strip read-out after corresponding dose and annealing

  18. Influence of soil γ-irradiation and spiking on sorption of p,p'-DDE and soil organic matter chemistry.

    Science.gov (United States)

    Škulcová, Lucia; Scherr, Kerstin E; Chrást, Lukáš; Hofman, Jakub; Bielská, Lucie

    2018-07-15

    The fate of organic chemicals and their metabolites in soils is often investigated in model matrices having undergone various pre-treatment steps that may qualitatively or quantitatively interfere with the results. Presently, effects associated with soil sterilization by γ-irradiation and soil spiking using an organic solvent were studied in one freshly spiked soil (sterilization prior to contamination) and its field-contaminated (sterilization after contamination) counterpart for the model organic compound 1,1-Dichloro-2,2-bis(4-chlorophenyl)ethene (p,p'-DDE). Changes in the sorption and potential bioavailability of spiked and native p,p'-DDE were measured by supercritical fluid extraction (SFE), XAD-assisted extraction (XAD), and solid-phase microextraction (SPME) and linked to qualitative changes in soil organic matter (SOM) chemistry measured by diffuse reflectance infrared Fourier-transform (DRIFT) spectroscopy. Reduced sorption of p,p´-DDE detected with XAD and SPME was associated more clearly with spiking than with sterilization, but SFE showed a negligible impact. Spiking resulted in an increase of the DRIFT-derived hydrophobicity index, but irradiation did not. Spectral peak height ratio descriptors indicated increasing hydrophobicity and hydrophilicity in pristine soil following sterilization, and a greater reduction of hydrophobic over hydrophilic groups as a consequence of spiking. In parallel, reduced sorption of p,p´-DDE upon spiking was observed. Based on the present samples, γ-irradiation appears to alter soil sorptive properties to a lesser extent when compared to common laboratory processes such as spiking with organic solvents. Copyright © 2018. Published by Elsevier Inc.

  19. Magnetic-entropy change in Mn1.1Fe0.9P0.7As0.3-xGe x

    International Nuclear Information System (INIS)

    Tegus, O.; Fuquan, B.; Dagula, W.; Zhang, L.; Brueck, E.; Si, P.Z.; Boer, F.R. de; Buschow, K.H.J.

    2005-01-01

    We have studied the magnetic properties and magnetic-entropy changes of Mn 1.1 Fe 0.9 P 0.7 As 0.3-x Ge x compounds with x = 0, 0.05, 0.1, 0.15 and 0.3. X-ray diffraction (XRD) study shows all the compounds crystallize in the Fe 2 P-type structure. Magnetic measurements show that the Curie temperature increases from 150 K for Mn 1.1 Fe 0.9 P 0.7 As 0.3 to 380 K for Mn 1.1 Fe 0.9 P 0.7 Ge 0.3 . A field-induced first-order magnetic phase transition is observed above the Curie temperature for the compounds with x up to 0.15. There exists an optimal composition in which the first-order phase transition is the sharpest. The optimal composition for this system is x = 0.1. The maximal magnetic-entropy change derived from the magnetization data is about 40 J/(kg K) for a field change from 0 to 3 T

  20. The Design and Manufacturing Report of Plug Type Non-Instrumented Rig for Irradiation Test in HANARO OR Hole

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dae Ho; Bang, Je Geon; Lim, Ik Sung; Kim, Sun Ki; Yang, Yong Sik; Song, Kun Woo

    2008-09-15

    This project is developed the plug type non-instrumented irradiation test rig of the advanced nuclear fuel in HANARO for pursuit advanced performance in High Performance Fuel Technology Development as a part Nuclear Mid and Long-term R and D Program. This irradiation rig was confirmed the integrity and HANARO core compatibility by the optimum design and the thermal hydraulic out-pile test in FIVPET. The characteristic of plug type non-instrument rig is to possible irradiation test of variable in-pile condition and reduced the wastes for reusable as function. This plug type non-instrumented rig was satisfied the quality assurance requirements and written out the end of manufacturing report. This plug type non-instrumented rig is adopt to the irradiation test for nuclear fuel irradiation test in HANARO OR hole.

  1. Quiescence does not affect p53 and stress response by irradiation in human lung fibroblasts

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Jiawen [Molecular Radiobiology Laboratory, Division of Cellular and Molecular Research (Singapore); Itahana, Koji, E-mail: koji.itahana@duke-nus.edu.sg [Cancer and Stem Cell Biology Program, Duke-NUS Graduate Medical School (Singapore); Baskar, Rajamanickam, E-mail: r.baskar@nccs.com.sg [Molecular Radiobiology Laboratory, Division of Cellular and Molecular Research (Singapore); Department of Radiation Oncology, National Cancer Centre (Singapore)

    2015-02-27

    Cells in many organs exist in both proliferating and quiescent states. Proliferating cells are more radio-sensitive, DNA damage pathways including p53 pathway are activated to undergo either G{sub 1}/S or G{sub 2}/M arrest to avoid entering S and M phase with DNA damage. On the other hand, quiescent cells are already arrested in G{sub 0}, therefore there may be fundamental difference of irradiation response between proliferating and quiescent cells, and this difference may affect their radiosensitivity. To understand these differences, proliferating and quiescent human normal lung fibroblasts were exposed to 0.10–1 Gy of γ-radiation. The response of key proteins involved in the cell cycle, cell death, and metabolism as well as histone H2AX phosphorylation were examined. Interestingly, p53 and p53 phosphorylation (Ser-15), as well as the cyclin-dependent kinase inhibitors p21 and p27, were induced similarly in both proliferating and quiescent cells after irradiation. Furthermore, the p53 protein half-life, and expression of cyclin A, cyclin E, proliferating cell nuclear antigen (PCNA), Bax, or cytochrome c expression as well as histone H2AX phosphorylation were comparable after irradiation in both phases of cells. The effect of radioprotection by a glycogen synthase kinase 3β inhibitor on p53 pathway was also similar between proliferating and quiescent cells. Our results showed that quiescence does not affect irradiation response of key proteins involved in stress and DNA damage at least in normal fibroblasts, providing a better understanding of the radiation response in quiescent cells, which is crucial for tissue repair and regeneration. - Highlights: • p53 response by irradiation was similar between proliferating and quiescent cells. • Quiescent cells showed similar profiles of cell cycle proteins after irradiation. • Radioprotection of GSK-3β inhibitor caused similar effects between these cells. • Quiescence did not affect p53 response despite its

  2. Quiescence does not affect p53 and stress response by irradiation in human lung fibroblasts

    International Nuclear Information System (INIS)

    Dai, Jiawen; Itahana, Koji; Baskar, Rajamanickam

    2015-01-01

    Cells in many organs exist in both proliferating and quiescent states. Proliferating cells are more radio-sensitive, DNA damage pathways including p53 pathway are activated to undergo either G 1 /S or G 2 /M arrest to avoid entering S and M phase with DNA damage. On the other hand, quiescent cells are already arrested in G 0 , therefore there may be fundamental difference of irradiation response between proliferating and quiescent cells, and this difference may affect their radiosensitivity. To understand these differences, proliferating and quiescent human normal lung fibroblasts were exposed to 0.10–1 Gy of γ-radiation. The response of key proteins involved in the cell cycle, cell death, and metabolism as well as histone H2AX phosphorylation were examined. Interestingly, p53 and p53 phosphorylation (Ser-15), as well as the cyclin-dependent kinase inhibitors p21 and p27, were induced similarly in both proliferating and quiescent cells after irradiation. Furthermore, the p53 protein half-life, and expression of cyclin A, cyclin E, proliferating cell nuclear antigen (PCNA), Bax, or cytochrome c expression as well as histone H2AX phosphorylation were comparable after irradiation in both phases of cells. The effect of radioprotection by a glycogen synthase kinase 3β inhibitor on p53 pathway was also similar between proliferating and quiescent cells. Our results showed that quiescence does not affect irradiation response of key proteins involved in stress and DNA damage at least in normal fibroblasts, providing a better understanding of the radiation response in quiescent cells, which is crucial for tissue repair and regeneration. - Highlights: • p53 response by irradiation was similar between proliferating and quiescent cells. • Quiescent cells showed similar profiles of cell cycle proteins after irradiation. • Radioprotection of GSK-3β inhibitor caused similar effects between these cells. • Quiescence did not affect p53 response despite its known role in

  3. SU-F-P-52: A Meta-Analysis of Controlled Clinical Trials Comparing Elective Nodal Irradiation with Involved-Field Irradiation for Conformal Or Intensity-Modulated Radiotherapy in Patients with Esophageal Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Bai, W; Zhang, R; Zhou, Z; Qiao, X [The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei (China)

    2016-06-15

    Purpose: To compare elective nodal irradiation with involved-field irradiation for three-dimensional conformal radiotherapy or intensity-modulated radiotherapy in patients with esophageal cancer by a metaanalysis. Methods: Wanfang, CNKI, VIP, CBM databases, PubMed, Embase and Cochrane Library were searched to identify the controlled clinical trials of elective nodal irradiation with involved-field irradiation for three-dimensional conformal radiotherapy or intensity-modulated radiotherapy in patients with esophageal cancer. The obtained data were analyzed using Stata 11.0. The difference between two groups was estimated by calculating the odds ratio (OR) with 95% confidence interval (95% CI). Results: A total of 12 controlled clinical trials involving 1095 esophageal cancer patients, which were selected according to inclusion and exclusion criteria, were included in this meta-analysis. The meta-analysis showed that the elective nodal irradiation group reduced the rates of out-field failure comparing with involved-field irradiation group (OR=3.727, P=0.007). However, the rates of ≥grades 3 acute radiation pneumonitis and esophagitis were significantly higher in the elective nodal irradiation group than in the involved-field irradiation group (OR=0.348, P=0.001, OR=0.385, P=0.000). 1-, 2-, 3-year local control rates (OR=0.966, P=0.837, OR=0.946, P=0.781; OR=0.732P=0.098) and 1-, 3-, 5-year survival rates were similar in the two groups ( OR=0.966, P=0.837; OR=0.946, P=0.781; OR=0.732, P=0.098; OR=0.952, P=0.756; OR=1.149, P=0.422; OR=0.768, P=0.120). It is the same with the rates of distant metastasis (OR=0.986, P=0.937). Conclusion: Compared with involved-field irradiation, the elective nodal irradiation can reduce the rates of out-field failure for three-dimensional conformal radiotherapy or intensity-modulated radiotherapy in patients with esophageal cancer. However, its advantage of local control and survival rates is not obvious and it increases the incidence

  4. Neutron irradiation effects on superconducting and stabilizing materials for fusion magnets

    International Nuclear Information System (INIS)

    Maurer, W.

    1984-05-01

    Available low-temperature neutron irradiation data for the superconductors NbTi and Nb 3 Sn and the stabilization materials Cu and Al are collected and maximum tolerable doses for these materials are defined. A neutron flux in a reactor of about 10 9 n/cm 2 s at the magnet position is expected. However, in fusion experiments the flux can be higher by an order of magnitude or more. The energy spectrum is similar to a fission reactor. A fluence of about 10 18 n/cm 2 results during the lifetime of a fusion magnet (about 20 full power years). At this fluence and energy spectrum no severe degradation of the superconducting properties of NbTi and Nb 3 Sn will occur. But the radiation-induced resistivity is for Cu about a twentieth of the room temperature resistivity and a tenth for Al. (orig.) [de

  5. Heat characteristic analysis of a conduction cooling toroidal-type SMES magnet

    International Nuclear Information System (INIS)

    Kim, K.M.; Kim, A.R.; Kim, J.G.; Kim, D.W.; Park, M.; Yu, I.K.; Eom, B.Y.; Sim, K.; Kim, S.H.; Shon, M.H.; Kim, H.J.; Bae, H.J.; Seong, K.C.

    2010-01-01

    This paper analyzed the heat characteristics of a conduction cooling toroidal-type SMES magnet. The authors designed and manufactured a conduction cooling toroidal-type SMES magnet which consists of 30 double pancake coils. One (a single pancake coil) of a double pancake coil is arranged at an angle of 6 o from each other. The shape of the toroidal-type SMES magnet was designed by a 3D CAD program. The heat invasion was investigated under no-load condition and the thermal characteristic of the toroidal-type SMES magnet was analyzed using the Finite Elements Method program. Both the analyzed and the experiment results are compared and discussed in detail.

  6. Development of references of anomalies detection on P91 material using Self-Magnetic Leakage Field (SMLF) technique

    Science.gov (United States)

    Husin, Shuib; Afiq Pauzi, Ahmad; Yunus, Salmi Mohd; Ghafar, Mohd Hafiz Abdul; Adilin Sekari, Saiful

    2017-10-01

    This technical paper demonstrates the successful of the application of self-magnetic leakage field (SMLF) technique in detecting anomalies in weldment of a thick P91 materials joint (1 inch thickness). Boiler components such as boiler tubes, stub boiler at penthouse and energy piping such as hot reheat pipe (HRP) and H-balance energy piping to turbine are made of P91 material. P91 is ferromagnetic material, therefore the technique of self-magnetic leakage field (SMLF) is applicable for P91 in detecting anomalies within material (internal defects). The technique is categorized under non-destructive technique (NDT). It is the second passive method after acoustic emission (AE), at which the information on structures radiation (magnetic field and energy waves) is used. The measured magnetic leakage field of a product or component is a magnetic leakage field occurring on the component’s surface in the zone of dislocation stable slipbands under the influence of operational (in-service) or residual stresses or in zones of maximum inhomogeneity of metal structure in new products or components. Inter-granular and trans-granular cracks, inclusion, void, cavity and corrosion are considered types of inhomogeneity and discontinuity in material where obviously the output of magnetic leakage field will be shown when using this technique. The technique does not required surface preparation for the component to be inspected. This technique is contact-type inspection, which means the sensor has to touch or in-contact to the component’s surface during inspection. The results of application of SMLF technique on the developed P91 reference blocks have demonstrated that the technique is practical to be used for anomaly inspection and detection as well as identification of anomalies’ location. The evaluation of this passive self-magnetic leakage field (SMLF) technique has been verified by other conventional non-destructive tests (NDTs) on the reference blocks where simulated

  7. U-turn type continuous irradiation method and device for radiation-irradiated capsule

    International Nuclear Information System (INIS)

    Kikuchi, Takayuki.

    1997-01-01

    A capsule to be irradiated is moved while being rotated in one of conveying shafts disposed in a reactor to conduct irradiation treatment. Then, the irradiated capsule is made U-turn in the reactor, inserted to the other conveying shaft and moved while being rotated to conduct irradiation treatment again, and then transported out of the reactor. The device comprises a rotational conveying shaft for moving the irradiated capsule while rotating it, a conveying gear for U-turning the irradiated capsule in the reactor and inserting it to the conveying shaft and a driving mechanism for synchronously rotating the conveying gear relative to the conveying shaft at a constant ratio. Mechanical time loss and manual operation time loss can be reduced upon loading and taking up of the irradiated capsule. Then, the amount of irradiation treatment per unit time is increased, and an optional neutron irradiation amount can be obtained thereby enabling to reduce operator's radiation exposure. (N.H.)

  8. Defects induced magnetic transition in Co doped ZnS thin films: Effects of swift heavy ion irradiations

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Shiv P., E-mail: shivpoojanbhola@gmail.com [Physics Department, University of Allahabad, Allahabad 211002 (India); Pivin, J.C. [CSNSM, IN2P3-CNRS, Batiment 108, F-91405 Orsay Campus (France); Patel, M.K; Won, Jonghan [Materials Science and Technology Division, MST-8, P.O.Box 1663, Mail Stop G755, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Chandra, Ramesh [Nanoscience Laboratory, IIC, Indian Institute of Technology, Roorkee 247667 (India); Kanjilal, D. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Kumar, Lokendra [Physics Department, University of Allahabad, Allahabad 211002 (India)

    2012-07-15

    The effect of swift heavy ions (SHI) on magnetic ordering in ZnS thin films with Co ions substituted on Zn sites is investigated. The materials have been synthesized by pulsed laser deposition on substrates held at 600 Degree-Sign C for obtaining films with wurtzite crystal structure and it showed ferromagnetic ordering up to room temperature with a paramagnetic component. 120 MeV Ag ions have been used at different fluences of 1 Multiplication-Sign 10{sup 11} ions/cm{sup 2} and 1 Multiplication-Sign 10{sup 12} ions/cm{sup 2} for SHI induced modifications. The long range correlation between paramagnetic spins on Co ions was destroyed by irradiation and the material became purely paramagnetic. The effect is ascribed to the formation of cylindrical ion tracks due to the thermal spikes resulting from electron-phonon coupling. - Highlights: Black-Right-Pointing-Pointer Effect of swift heavy ions on magnetic ordering in Co doped ZnS thin films are presented. Black-Right-Pointing-Pointer Magnetization in the pristine films is composed of ferromagnetic and paramagnetic components. Black-Right-Pointing-Pointer The films become purely paramagnetic after swift heavy ions irradiation. Black-Right-Pointing-Pointer The magnetic transition is ascribed to the formation of ion track (or cylindrical defects) due to the thermal spikes.

  9. p-brane dyons and electric-magnetic duality

    International Nuclear Information System (INIS)

    Deser, S.; Henneaux, M.; Teitelboim, C.

    1998-01-01

    We discuss dyons, charge quantization and electric-magnetic duality for self-interacting, abelian, p-form theories in the space-time dimensions D=2(p+1) where dyons can be present. The corresponding quantization conditions and duality properties are strikingly different depending on whether p is odd or even. If p is odd one has the familiar e anti g-g anti e=2πnℎ, whereas for even p one finds the opposite relative sign, e anti g+g anti e=2πnℎ. These conditions are obtained by introducing Dirac strings and taking due account of the multiple connectedness of the configuration space of the strings and the dyons. A two-potential formulation of the theory that treats the electric and magnetic sources on the same footing is also given. Our results hold for arbitrary gauge invariant self-interaction of the fields and are valid irrespective of their duality properties. (orig.)

  10. Polymeric materials obtained by electron beam irradiation

    International Nuclear Information System (INIS)

    Dragusin, M.; Moraru, R.; Martin, D.; Radoiu, M.; Marghitu, S.; Oproiu, C.

    1995-01-01

    Research activities in the field of electron beam irradiation of monomer aqueous solution to produce polymeric materials used for waste waters treatment, agriculture and medicine are presented. The technologies and special features of these polymeric materials are also described. The influence of the chemical composition of the solution to ba irradiated, absorbed dose level and absorbed dose rate level are discussed. Two kinds of polyelectrolytes, PA and PV types and three kinds of hydrogels, pAAm, pAAmNa and pNaAc types, the production of which was first developed with IETI-10000 Co-60 source and then adapted to the linacs built in Accelerator Laboratory, are described. (author)

  11. Floquet Weyl semimetals in light-irradiated type-II and hybrid line-node semimetals

    Science.gov (United States)

    Chen, Rui; Zhou, Bin; Xu, Dong-Hui

    2018-04-01

    Type-II Weyl semimetals have recently attracted intensive research interest because they host Lorentz-violating Weyl fermions as quasiparticles. The discovery of type-II Weyl semimetals evokes the study of type-II line-node semimetals (LNSMs) whose linear dispersion is strongly tilted near the nodal ring. We present here a study on the circularly polarized light-induced Floquet states in type-II LNSMs, as well as those in hybrid LNSMs that have a partially overtilted linear dispersion in the vicinity of the nodal ring. We illustrate that two distinct types of Floquet Weyl semimetal (WSM) states can be induced in periodically driven type-II and hybrid LNSMs, and the type of Floquet WSMs can be tuned by the direction and intensity of the incident light. We construct phase diagrams of light-irradiated type-II and hybrid LNSMs which are quite distinct from those of light-irradiated type-I LNSMs. Moreover, we show that photoinduced Floquet type-I and type-II WSMs can be characterized by the emergence of different anomalous Hall conductivities.

  12. G2-block after irradiation of cells with different p53 status

    International Nuclear Information System (INIS)

    Zoelzer, Friedo; Jagetia, Ganesh; Streffer, Christian

    2014-01-01

    Although it is clear that functional p53 is not required for radiation-induced G 2 block, certain experimental findings suggest a role for p53 in this context. For instance, as we also confirm here, the maximum accumulation in the G 2 compartment after X-ray exposure occurs much later in p53 mutants than in wild types. It remains to be seen, however, whether this difference is due to a longer block in the G 2 phase itself. We observed the movement of BrdU-labeled cells through G 2 and M into G 1 . From an analysis of the fraction of labeled cells that entered the second posttreatment cell cycle, we were able to determine the absolute duration of the G 2 and M phases in unirradiated and irradiated cells. Our experiments with four cell lines, two melanomas and two squamous carcinomas, showed that the radiation-induced delay of transition through the G 2 and M phases did not correlate with p53 status. We conclude that looking at the accumulation of cells in the G 2 compartment alone is misleading when differences in the G 2 block are investigated and that the G 2 block itself is indeed independent of functional p53. (orig.) [de

  13. Long term low dose rate irradiation causes recovery from type II diabetes and suppression of aging in type II diabetes-prone mice

    International Nuclear Information System (INIS)

    Namura, T.; Oda, T.

    2003-01-01

    The effects of low dose rate gamma irradiation on model C57BL/KsJ-db/db mice with Type II diabetes mellitus was investigated. These mice develop Type II diabetes by 10 weeks of age, due to obesity, and are characterized by hyperinsulinemia. A group of 12 female 10-week old mice were irradiated at 0.65 mGy/hr in the low dose rate irradiation facility in the Low Dose Radiation Research Center. The urine glucose levels of all of the mice were strongly positive at the beginning of the irradiation. In the irradiated group, a decrease in the glucose level was observed in three mice, one in the 35th week, another in the 52nd week and the third in the 80th week. No recovery from the diabetes was observed in the 12 mice of non-irradiated control group. There was no systematic change of body weight or consumption of food and drinking water between the irradiated group and the non-irradiated group or between the recovered mice and the non-recovered mice. Survival was better in the irradiated group. The surviving fraction at the age of 90 weeks was 75 % in the irradiated group but only 40 % in the non-irradiated. A marked difference was also observed in the appearance of the coat hair, skin and tail. The irradiated group was in much better condition. Mortality was delayed and the healthy appearance was prolonged in the irradiated mice by about 20-30 weeks compared with the control mice. These results suggest that the low dose irradiation modified the condition of the diabetic mice, leading not only to recovery from diabetes, but also to suppression of the aging process

  14. Sub-micron magnetic patterns and local variations of adhesion force induced in non-ferromagnetic amorphous steel by femtosecond pulsed laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Huiyan; Feng, Yuping [Departament de Física, Universitat Autònoma de Barcelona, Bellaterra, E08193 (Spain); Nieto, Daniel [Microoptics and GRIN Optics Group, Applied Physics Department, University of Santiago de Compostela, E15782 Santiago de Compostela (Spain); García-Lecina, Eva [Unidad de Superficies Metálicas, IK4-CIDETEC, E20009 Donostia-San Sebastián Gipuzkoa (Spain); Mcdaniel, Clare [National Centre for Laser Applications, School of Physics, National University of Ireland, Galway (Ireland); Díaz-Marcos, Jordi [Unitat de Tècniques Nanomètriques, Centres Científics i Tecnològics, Universitat de Barcelona, E08028 Barcelona (Spain); Flores-Arias, María Teresa [Microoptics and GRIN Optics Group, Applied Physics Department, University of Santiago de Compostela, E15782 Santiago de Compostela (Spain); O’Connor, Gerard M. [National Centre for Laser Applications, School of Physics, National University of Ireland, Galway (Ireland); Baró, Maria Dolors [Departament de Física, Universitat Autònoma de Barcelona, Bellaterra, E08193 (Spain); Pellicer, Eva, E-mail: eva.pellicer@uab.cat [Departament de Física, Universitat Autònoma de Barcelona, Bellaterra, E08193 (Spain); and others

    2016-05-15

    Highlights: • Formation of ripples after femtosecond pulsed laser irradiation (FSPLI) of metallic glass was studied. • Magnetic patterning at the surface of non-ferromagnetic amorphous steel was induced by FSPLI. • The origin of the generated ferromagnetism is the laser-induced devitrification. - Abstract: Periodic ripple and nanoripple patterns are formed at the surface of amorphous steel after femtosecond pulsed laser irradiation (FSPLI). Formation of such ripples is accompanied with the emergence of a surface ferromagnetic behavior which is not initially present in the non-irradiated amorphous steel. The occurrence of ferromagnetic properties is associated with the laser-induced devitrification of the glassy structure to form ferromagnetic (α-Fe and Fe{sub 3}C) and ferrimagnetic [(Fe,Mn){sub 3}O{sub 4} and Fe{sub 2}CrO{sub 4}] phases located in the ripples. The generation of magnetic structures by FSPLI turns out to be one of the fastest ways to induce magnetic patterning without the need of any shadow mask. Furthermore, local variations of the adhesion force, wettability and nanomechanical properties are also observed and compared to those of the as-cast amorphous alloy. These effects are of interest for applications (e.g., biological, magnetic recording, etc.) where both ferromagnetism and tribological/adhesion properties act synergistically to optimize material performance.

  15. Low energy proton irradiation effects on InP/InGaAs DHBTs and InP-base frequency dividers

    Science.gov (United States)

    Zhang, Xingyao; Li, Yudong; Guo, Qi; Feng, Jie

    2018-03-01

    InP/InGaAs DHBTs and frequency dividers are irradiated by low energy proton, and displacement damage effect of the devices are analyzed. InP/InGaAs DHBTs has been made DC characteristics measurements, and the function measurement for frequency dividers has been done both before and after proton irradiation. The breakdown voltage of InP DHBTs drop to 3.7V When the fluence up to 5x1013 protons/cm2. Meanwhile, the function of frequency dividers get out of order. Degradation of DC characteristics of DHBTs are due to the radiation-induced defects in the quasi neutral base and the space charge region of base-collector and base-emitter junctions. The performance deterioration of DHBTs induce the fault of frequency dividers, and prescaler may be the most sensitive circuit.

  16. Charge collection in Si detectors irradiated in situ at superfluid helium temperature

    Energy Technology Data Exchange (ETDEWEB)

    Verbitskaya, Elena, E-mail: elena.verbitskaya@cern.ch [Ioffe Institute, 26 Politekhnicheskaya str., St. Petersburg 194021 (Russian Federation); Eremin, Vladimir; Zabrodskii, Andrei [Ioffe Institute, 26 Politekhnicheskaya str., St. Petersburg 194021 (Russian Federation); Dehning, Bernd; Kurfürst, Christoph; Sapinski, Mariusz; Bartosik, Marcin R. [CERN, CH-1211, Geneva 23 (Switzerland); Egorov, Nicolai [Research Institute of Material Science and Technology, 4 Passage 4806, Moscow, Zelenograd 124460 (Russian Federation); Härkönen, Jaakko [Helsinki Institute of Physics, P.O.Box 64 (Gustaf Hallströmin katu 2) FI-00014 University of Helsinki (Finland)

    2015-10-01

    Silicon and diamond detectors operated in a superfluid helium bath are currently being considered for the upgrade of the LHC beam loss monitoring system. The detectors would be installed in immediate proximity of the superconducting coils of the triplet magnets. We present here the results of the in situ irradiation test for silicon detectors using 23 GeV protons while keeping the detectors at a temperature of 1.9 K. Red laser (630 nm) Transient Current Technique and DC current measurements were used to study the pulse response and collected charge for silicon detectors irradiated to a maximum radiation fluence of 1×10{sup 16} p/cm{sup 2}. The dependence between collected charge and irradiation fluence was parameterized using the Hecht equation and assumption of a uniform electric field distribution. The collected charge was found to degrade with particle fluence for both bias polarities. We observed that the main factor responsible for this degradation was related to trapping of holes on the donor-type radiation-induced defects. In contrast to expectations, along with formation of donors, acceptor-type defects (electron traps) are introduced into the silicon bulk. This suggests that the current models describing charge collection in irradiated silicon detectors require an extension for taking into account trapping at low temperatures with a contribution of shallow levels. New in situ irradiation tests are needed and planned now to extend statistics of the results and gain a deeper insight into the physics of low temperature detector operation in harsh radiation environment. - Highlights: • Si detectors irradiated in situ at 1.9 K by 23 GeV protons are further studied. • Trapping parameters are derived from the fits of collected charge vs. fluence data. • Acceptor-type defects are likely to be induced along with donor-type ones. • Trapping of holes has a dominating effect on the collected charge degradation. • New tests are planned to gain deeper insight

  17. Gamma irradiation testing of prototype ITER in-vessel magnetic pick-up coils

    International Nuclear Information System (INIS)

    Vermeeren, Ludo; Leysen, Willem

    2013-01-01

    Highlights: ► We tested five prototype ITER in-vessel coils up to a gamma dose of 72 MGy. ► Before and after irradiation thermal tests were also performed from 30 °C till 130 °C. ► The continuity resistances and the insulation resistances were continuously monitored. ► The observed behavior of all coils was satisfactory in all conditions. ► For the further design the mechanical robustness should be taken into account. -- Abstract: To fulfill the requirements for ITER in-vessel magnetic diagnostics, several coil prototypes have been developed, aiming at minimizing the disturbing effects of temperature gradients and radiation induced phenomena. As a first step in the radiation resistance testing of these prototypes, an in-situ high dose rate gamma radiation test on a selection of prototypes was performed. The aim of this test was to get a first experimental feedback regarding the behavior of the pick-up coil prototypes under radiation. Five prototypes (a coil wound with glass-insulated copper wire, two LTCC coils and two HTCC coils) were irradiated at a dose rate of 46 kGy/h up to a total dose of 72 MGy and at a temperature of 50 °C. During the irradiation, the continuity resistances and the insulation resistances were continuously measured. Before and after irradiation reference data were recorded as a function of temperature (from 30 °C to 130 °C). This paper includes the results of the temperature and irradiation tests and a discussion of the behavior of the prototype coils in terms of electrical and mechanical properties

  18. Performance, defect behavior and carrier enhancement in low energy, proton irradiated p+nn+ InP solar cells

    Science.gov (United States)

    Weinberg, I.; Rybicki, G. C.; Vargas-Aburto, C.; Jain, R. K.; Scheiman, D.

    1994-01-01

    The highest AMO efficiency (19.1 percent) InP solar cell consisted of an n+pp+ structure epitaxially grown on a p+ InP substrate. However, the high cost and relative fragility of InP served as motivation for research efforts directed at heteroepitaxial growth of InP on more viable substrates. The highest AMO efficiency (13.7 percent) for this type of cell was achieved using a GaAs substrate. Considering only cost and fracture toughness, Si would be the preferred substrate. The fact that Si is a donor in InP introduces complexities which are necessary in order to avoid the formation of an efficiency limiting counterdiode. One method used to overcome this problem lies in employing an n+p+ tunnel junction in contact with the cell's p region. A simpler method consists of using an n+ substrate and processing the cell in the p+ nn+ configuration. This eliminates the need for a tunnel junction. Unfortunately, the p/n configuration has received relatively little attention the best cell with this geometry having achieved an efficiency of 17 percent. Irradiation of these homoepitaxial cells, with 1 Mev electrons, showed that they were slightly more radiation resistant than diffused junction n/p cells. Additional p/n InP cells have been processed by some activity aimed at diffusion. Currently, there has been some activity aimed at producing heteroepitaxial p+nn+ InP cells using n+ Ge substrates. Since, like Si, Ge is an n-dopant in InP, use of this configuration obviates the need for a tunnel junction. Obviously, before attempting to process heteroepitaxial cells, one must produce a reasonably good homoepitaxial cell. In the present case we focus our attention on homoepitaxially on an n+ Ge substrate.

  19. The Influence of High-Energy Electrons Irradiation on Surface of n-GaP and on Au/n-GaP/Al Schottky Barrier Diode

    Science.gov (United States)

    Demir, K. Çinar; Kurudirek, S. V.; Oz, S.; Biber, M.; Aydoğan, Ş.; Şahin, Y.; Coşkun, C.

    We fabricated 25 Au/n-GaP/Al Schottky devices and investigated the influence of high electron irradiation, which has 12MeV on the devices, at room temperature. The X-ray diffraction patterns, scanning electron microscopic images and Raman spectra of a gallium phosphide (GaP) semiconductor before and after electron irradiation have been analyzed. Furthermore, some electrical measurements of the devices were carried out through the current-voltage (I-V) and capacitance-voltage (C-V) measurements. From the I-V characteristics, experimental ideality factor n and barrier height Φ values of these Schottky diodes have been determined before and after irradiation, respectively. The results have also been analyzed statically, and a gauss distribution has been obtained. The built-in potential Vbi, barrier height Φ, Fermi level EF and donor concentration Nd values have been determined from the reverse bias C-V and C-2-V curves of Au/n-GaP/Al Schottky barrier diodes at 100kHz before and after 12MeV electron irradiation. Furthermore, we obtained the series resistance values of Au/n-GaP/Al Schottky barrier diodes with the help of different methods. Experimental results confirmed that the electrical characterization of the device changed with the electron irradiation.

  20. Behavior of Type 316 stainless steel under simulated fusion reactor irradiation

    International Nuclear Information System (INIS)

    Wiffen, F.W.; Maziasz, P.J.; Bloom, E.E.; Stiegler, J.O.; Grossbeck, M.L.

    1978-05-01

    Fusion reactor irradiation response in alloys containing nickel can be simulated in thermal-spectrum fission reactors, where displacement damage is produced by the high-energy neutrons and helium is produced by the capture of two thermal neutrons in the reactions: 58 Ni + n → 59 Ni + γ; 59 Ni + n → 56 Fe + α. Examination of type 316 stainless steel specimens irradiated in HFIR has shown that swelling due to cavity formation and degradation of mechanical properties are more severe than can be predicted from fast reactor irradiations, where the helium contents produced are far too low to simulate fusion reactor service. Swelling values are greater and the temperature dependence of swelling is different than in the fast reactor case

  1. Charge collection in Si detectors irradiated in situ at superfluid helium temperature

    Science.gov (United States)

    Verbitskaya, Elena; Eremin, Vladimir; Zabrodskii, Andrei; Dehning, Bernd; Kurfürst, Christoph; Sapinski, Mariusz; Bartosik, Marcin R.; Egorov, Nicolai; Härkönen, Jaakko

    2015-10-01

    Silicon and diamond detectors operated in a superfluid helium bath are currently being considered for the upgrade of the LHC beam loss monitoring system. The detectors would be installed in immediate proximity of the superconducting coils of the triplet magnets. We present here the results of the in situ irradiation test for silicon detectors using 23 GeV protons while keeping the detectors at a temperature of 1.9 K. Red laser (630 nm) Transient Current Technique and DC current measurements were used to study the pulse response and collected charge for silicon detectors irradiated to a maximum radiation fluence of 1×1016 p/cm2. The dependence between collected charge and irradiation fluence was parameterized using the Hecht equation and assumption of a uniform electric field distribution. The collected charge was found to degrade with particle fluence for both bias polarities. We observed that the main factor responsible for this degradation was related to trapping of holes on the donor-type radiation-induced defects. In contrast to expectations, along with formation of donors, acceptor-type defects (electron traps) are introduced into the silicon bulk. This suggests that the current models describing charge collection in irradiated silicon detectors require an extension for taking into account trapping at low temperatures with a contribution of shallow levels. New in situ irradiation tests are needed and planned now to extend statistics of the results and gain a deeper insight into the physics of low temperature detector operation in harsh radiation environment.

  2. Ion beam irradiation effects in strontium zirconium phosphate with NZP-structure type

    International Nuclear Information System (INIS)

    Gregg, Daniel J.; Karatchevtseva, Inna; Thorogood, Gordon J.; Davis, Joel; Bell, Benjamin D.C.; Jackson, Matthew; Dayal, Pranesh; Ionescu, Mihail; Triani, Gerry; Short, Ken; Lumpkin, Gregory R.; Vance, Eric R.

    2014-01-01

    Ceramics with the sodium zirconium phosphate or NZP type structure have potential as nuclear waste form and inert matrix materials. For both applications the material will be subjected to self-radiation damage from α-decay of the incorporated actinides. In this study, ion-beam irradiation using Au- and He-ions has been used to simulate the consequences of α-decay and the effects of irradiation on the structural and macroscopic properties (density and hardness) have been investigated. Irradiation by Au-ions resulted in a significant volume contraction of ∼7%, a reduction in hardness of ∼30% and a loss in long-range order at fluences above 10 14 Au-ions/cm 2 . In contrast, little effect on the material properties was noted for samples irradiated with He-ions up to a fluence of 10 17 ions/cm 2 . Thermal annealing was investigated for the highest fluence Au-ion irradiated sample and significant decomposition was observed

  3. Effects of recombinant plasmid pEgr-p53 transfected stably in combination with X-irradiation on cell cycle progression and proliferation in human SKOV-3 tumor cells in vitro

    International Nuclear Information System (INIS)

    Dong Lihua; Liu Feng; Li Yanbo; Fu Shibo; Gong Shouliang

    2008-01-01

    Objective: To investigate the effect of recombinant plasmid pEgr-hp53 transfected stably in combination with X-ray irradiation on the cell cycle progression and the proliferation in human SKOV-3 tumor cells. Methods: pEgr-hp53 and pcDNA3.1 packaged with liposome were stably transfected into SKOV-3 cells in vitro. SKOV-3-hp53 and SKOV-3-vect were irradiated with 0, 0.5, 2.0 and 5.0 Gy X-rays, respectively, i.e. 8 experimental groups. The SKOV-3 cell proliferation and the cell cycle progression were measured with flow cytometry and cell growth curve, respectively. Results: Compared with 0 Gy group, the cell counts in SKOV-3- hp53 plus different doses of irradiation groups 2 d after irradiation decreased significantly (P 0 /G 1 cells increased significantly (P 2 /M cells decreased in varying degrees. The cell counts in SKOV-3-hp53 plus irradiation group were significantly lower than those in corresponding SKOV-3-vect plus irradiation group, the cell counts 4-8 d after irradiation with 0.5 Gy, 2 d after 2.0 Gy irradiation and 6 d after 5.0 Gy irradiation decreased significantly (P 0 /G 1 cells increased significantly (P 2 /M cells decreased significantly (P 1 arrest in SKOV-3 cells and inhibits the cell proliferation. Ionizing radiation can activate early growth response-1 (Egr-1) gene promoter and increase the expression of p53 gene, and enhance the inhibition of tumor cell growth. (authors)

  4. Associations between tumor types in irradiated BALB/c female mice

    International Nuclear Information System (INIS)

    Storer, J.B.

    1982-01-01

    Associations between pairs of 12 different tumor types were estimated for a population of over 3800 irradiated BALB/c female mice. The associations were adjusted for age and radiation dose. Of the 66 pairs of tumor types, 21 showed significant positive or negative associations. Of these, 8 were considered to be spurious, principally because one or both of the tumors was rapidly lethal, leading to an apparent negative association. Six of the remaining 13 significant associations involed tumors of endocrine organs or tumors known to be endocrine related. Six others involved associations between lung, vascular tissue, or reticular tissue tumors, and tumors of endocrine organs. The remaining and highly negative association was between reticulum cell sarcomas and other lymphomas and leukemias. It was concluded that in irradiated female mice of this strain, at least, tumors are not independent and that alterations in host factors (principally endocrine) lead to animals developing both tumors (positive associations) or to one tumor but not the other (negative associations)

  5. Inhibition of human colorectal adenocarcinoma cells with AdCMV-p53 gene transfection induced by irradiation

    International Nuclear Information System (INIS)

    Liu Bing; Min Fengling; Xie Yi; Zhou Qingming; Duan Xin; Chinese Academy of Sciences, Beijing; Zhang Hong; Li Wenjian; Hao Jifang; Zhou Guangming; Gao Qingxiang

    2006-01-01

    The effect of AdCMV-p53 gene transfection induced by γ-ray irradiation on human colorectal adenocarcinoma cells was investigated. The HT-29 cells were irradiated by 0.5, 1.0, 2.0 Gy 60 Co γ-rays, then were transfected with AdCMV-GFP (a replication of deficient recombinant adenoviral vector containing a CMV promoter and green fluorescent protein) or AdCMV-p53 (a replication of deficient recombinant adenoviral vector containing a CMV promoter and carrying human wild p53 gene). Cytotoxity was measured by clonogenic survival assay; apoptosis and the p53 expression were determined by flow cytometry. The results show that the pre-exposure of 0.5 Gy 60 Co γ-rays significantly enhanced the inhibition of HT-29 cells with AdCMV-53 transfection and promoted cell apoptosis. The inhibition rates for the groups of pre-exposure with 0.5 Gy and transfection with 40 and 80 MOI AdCMV-p53 were 50% and 20% higher than those for the groups of the mere transfection, and 40% more than the mere irradiation group. In the case of higher than 0.5 Gy pre-exposure, no significant difference was found between the pre-exposure with transfection group and the mere irradiation group. So 0.5 Gy pre-irradiation and AdCMV-p53 transfection obviously increases the inhibition of HT-29 cells with AdCMV-p53 transfection. The optimum condition is the lower than 1.0 Gy pre-exposure combined with the lower than 80 MOI AdCMV-p53 transfection. (authors)

  6. Moessbauer spectroscopy of He irradiated austenitic stainless steel SUS304 at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Horii, Kiyomasa; Ishibashi, Tetsu; Toriyama, Tamotsu; Wakabayashi, Hidehiko; Iijima, Hiroshi [Musashi Inst. of Tech., Tokyo (Japan); Kawasaki, Katsunori; Hayashi, Nobuyuki; Sakamoto, Isao

    1996-04-01

    SUS 304 austenitic stainless steel causes the magnetic transition at 60 K, and the Young`s modulus lowers. In addition, its composition elements have the large (n,{alpha}) reaction cross section to high energy neutrons, and helium is apt to be generated, and this is a factor that lowers the material strength. In the He-irradiated parts in austenitic stainless steel, the precursory state of martensite transformation should exist, and its effect is considered to be observable by carrying out low temperature Moessbauer spectroscopy. As to the preparation of He-irradiation samples, the SUS 304 foils used and the irradiation conditions are described. The measurement of low temperature Moessbauer spectra for the samples without irradiation and with irradiation is reported. In order to determine the magnetic transition point, the thermal scanning measurement was carried out for the samples without or with irradiation. The martensite transformation was measured by X-ray diffraction and transmission type Moessbauer spectroscopy. In order to observe the state of the sample surfaces, the measurement by internal conversion electron Moessbauer spectroscopy was performed. These results and the temperature dependence of the Moessbauer spectra for the irradiated parts are reported. (K.I.)

  7. Moessbauer spectroscopy of He irradiated austenitic stainless steel SUS304 at low temperature

    International Nuclear Information System (INIS)

    Horii, Kiyomasa; Ishibashi, Tetsu; Toriyama, Tamotsu; Wakabayashi, Hidehiko; Iijima, Hiroshi; Kawasaki, Katsunori; Hayashi, Nobuyuki; Sakamoto, Isao.

    1996-01-01

    SUS 304 austenitic stainless steel causes the magnetic transition at 60 K, and the Young's modulus lowers. In addition, its composition elements have the large (n,α) reaction cross section to high energy neutrons, and helium is apt to be generated, and this is a factor that lowers the material strength. In the He-irradiated parts in austenitic stainless steel, the precursory state of martensite transformation should exist, and its effect is considered to be observable by carrying out low temperature Moessbauer spectroscopy. As to the preparation of He-irradiation samples, the SUS 304 foils used and the irradiation conditions are described. The measurement of low temperature Moessbauer spectra for the samples without irradiation and with irradiation is reported. In order to determine the magnetic transition point, the thermal scanning measurement was carried out for the samples without or with irradiation. The martensite transformation was measured by X-ray diffraction and transmission type Moessbauer spectroscopy. In order to observe the state of the sample surfaces, the measurement by internal conversion electron Moessbauer spectroscopy was performed. These results and the temperature dependence of the Moessbauer spectra for the irradiated parts are reported. (K.I.)

  8. Transport studies in p-type double quantum well samples

    International Nuclear Information System (INIS)

    Hyndman, R.J.

    2000-01-01

    The motivation for the study of double quantum well samples is that the extra spatial degree of freedom can modify the ground state energies of the system, leading to new and interesting many body effects. Electron bi-layers have been widely studied but the work presented here is the first systematic study of transport properties of a p-type, double quantum well system. The samples, grown on the 311 plane, consisted of two 100A GaAs wells separated by a 30A AlAs barrier. The thin barrier in our structures, gives rise to very strong inter-layer Coulombic interactions but in contrast to electron double quantum well samples, tunnelling between the two wells is very weak. This is due to the large effective mass of holes compared with electrons. It is possible to accurately control the total density of a sample and the relative occupancy of each well using front and back gates. A systematic study of the magnetoresistance properties of the p-type bi-layers, was carried out at low temperatures and in high magnetic fields, for samples covering a range of densities. Considerable care was required to obtain reliable results as the samples were extremely susceptible to electrical shock and were prone to drift in density slowly over time. With balanced wells, the very low tunnelling in the p-type bi-layer leads to a complete absence of all odd integers in both resistance and thermopower except for the v=1 state, ( v 1/2 in each layer) where v is the total Landau level filling factor. Unlike other FQHE features the v=1 state strengthens with increased density as inter-layer interactions increase in strength over intra-layer interactions. The state is also destroyed at a critical temperature, which is much lower than the measured activation temperature. This is taken as evidence for a finite temperature phase transition predicted for the bi-layer v=1. From the experimental observations, we construct a phase diagram for the state, which agree closely with theoretical predictions

  9. Re-irradiation for metastatic brain tumors with whole-brain radiotherapy

    International Nuclear Information System (INIS)

    Akiba, Takeshi; Kunieda, Etsuo; Kogawa, Asuka; Komatsu, Tetsuya; Tamai, Yoshifumi; Ohizumi, Yukio

    2012-01-01

    The objective of this study was to determine whether second whole-brain irradiation is beneficial for patients previously treated with whole-brain irradiation. A retrospective analysis was done for 31 patients with brain metastases who had undergone re-irradiation. Initial whole-brain irradiation was performed with 30 Gy/10 fractions for 87% of these patients. Whole-brain re-irradiation was performed with 30 Gy/10 fractions for 42% of these patients (3-40 Gy/1-20 fractions). Three patients underwent a third whole-brain irradiation. The median interval between the initial irradiation and re-irradiation was 10 months (range: 2-69 months). The median survival time after re-irradiation was 4 months (range: 1-21 months). The symptomatic improvement rate after re-irradiation was 68%, and the partial and complete tumor response rate was 55%. Fifty-two percent of the patients developed Grade 1 acute reactions. On magnetic resonance imaging, brain atrophy was observed in 36% of these patients after the initial irradiation and 74% after re-irradiation. Grade ≥2 encephalopathy or cognitive disturbance was observed in 10 patients (32%) after re-irradiation. Based on univariate analysis, significant factors related to survival after re-irradiation were the location of the primary cancer (P=0.003) and the Karnofsky performance status at the time of re-irradiation (P=0.008). A Karnofsky performance status ≥70 was significant based on multivariate analysis (P=0.050). Whole-brain re-irradiation for brain metastases placed only a slight burden on patients and was effective for symptomatic improvement. However, their remaining survival time was limited and the incidence of cognitive disturbance was rather high. (author)

  10. Profitability of an Co 60 semi-industrial irradiator type Gamma Beam 651 Pt

    International Nuclear Information System (INIS)

    Cruz Z, E.

    1997-01-01

    It is described the capacity in volume of processed material by irradiation interesting interesting for the industry and how many laboratory samples can be processed. It is showed the costs of the annual processing, that is, the relation between the volume of sterilized material and his cost, this give us an idea about the profits for this type of gamma irradiators designed for low capacity, where is necessary to define the effective area of sterilization using high dose dosimetry. Also have been compared the maintenance costs, operation and salaries including monetary devaluation in function of the real production of the irradiation processing. Finally, it is remarked the objectives and essential characteristics of this semi-industrial irradiator. (Author)

  11. SCALING LAW OF RELATIVISTIC SWEET-PARKER-TYPE MAGNETIC RECONNECTION

    International Nuclear Information System (INIS)

    Takahashi, Hiroyuki R.; Kudoh, Takahiro; Masada, Youhei; Matsumoto, Jin

    2011-01-01

    Relativistic Sweet-Parker-type magnetic reconnection is investigated by relativistic resistive magnetohydrodynamic (RRMHD) simulations. As an initial setting, we assume anti-parallel magnetic fields and a spatially uniform resistivity. A perturbation imposed on the magnetic fields triggers magnetic reconnection around a current sheet, and the plasma inflows into the reconnection region. The inflows are then heated due to ohmic dissipation in the diffusion region and finally become relativistically hot outflows. The outflows are not accelerated to ultrarelativistic speeds (i.e., Lorentz factor ≅ 1), even when the magnetic energy dominates the thermal and rest mass energies in the inflow region. Most of the magnetic energy in the inflow region is converted into the thermal energy of the outflow during the reconnection process. The energy conversion from magnetic to thermal energy in the diffusion region results in an increase in the plasma inertia. This prevents the outflows from being accelerated to ultrarelativistic speeds. We find that the reconnection rate R obeys the scaling relation R≅S -0.5 , where S is the Lundquist number. This feature is the same as that of non-relativistic reconnection. Our results are consistent with the theoretical predictions of Lyubarsky for Sweet-Parker-type magnetic reconnection.

  12. Analytical model and design of spoke-type permanent-magnet machines accounting for saturation and nonlinearity of magnetic bridges

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Peixin; Chai, Feng [State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin 150001 (China); Department of Electrical Engineering, Harbin Institute of Technology, Harbin 150001 (China); Bi, Yunlong [Department of Electrical Engineering, Harbin Institute of Technology, Harbin 150001 (China); Pei, Yulong, E-mail: peiyulong1@163.com [Department of Electrical Engineering, Harbin Institute of Technology, Harbin 150001 (China); Cheng, Shukang [State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin 150001 (China); Department of Electrical Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2016-11-01

    Based on subdomain model, this paper presents an analytical method for predicting the no-load magnetic field distribution, back-EMF and torque in general spoke-type motors with magnetic bridges. Taking into account the saturation and nonlinearity of magnetic material, the magnetic bridges are equivalent to fan-shaped saturation regions. For getting standard boundary conditions, a lumped parameter magnetic circuit model and iterative method are employed to calculate the permeability. The final field domain is divided into five types of simple subdomains. Based on the method of separation of variables, the analytical expression of each subdomain is derived. The analytical results of the magnetic field distribution, Back-EMF and torque are verified by finite element method, which confirms the validity of the proposed model for facilitating the motor design and optimization. - Highlights: • The no-load magnetic field of poke-type motors is firstly calculated by analytical method. • The magnetic circuit model and iterative method are employed to calculate the permeability. • The analytical expression of each subdomain is derived.. • The proposed method can effectively reduce the predesign stages duration.

  13. Analytical model and design of spoke-type permanent-magnet machines accounting for saturation and nonlinearity of magnetic bridges

    International Nuclear Information System (INIS)

    Liang, Peixin; Chai, Feng; Bi, Yunlong; Pei, Yulong; Cheng, Shukang

    2016-01-01

    Based on subdomain model, this paper presents an analytical method for predicting the no-load magnetic field distribution, back-EMF and torque in general spoke-type motors with magnetic bridges. Taking into account the saturation and nonlinearity of magnetic material, the magnetic bridges are equivalent to fan-shaped saturation regions. For getting standard boundary conditions, a lumped parameter magnetic circuit model and iterative method are employed to calculate the permeability. The final field domain is divided into five types of simple subdomains. Based on the method of separation of variables, the analytical expression of each subdomain is derived. The analytical results of the magnetic field distribution, Back-EMF and torque are verified by finite element method, which confirms the validity of the proposed model for facilitating the motor design and optimization. - Highlights: • The no-load magnetic field of poke-type motors is firstly calculated by analytical method. • The magnetic circuit model and iterative method are employed to calculate the permeability. • The analytical expression of each subdomain is derived.. • The proposed method can effectively reduce the predesign stages duration.

  14. Coronal Magnetic Field Lines and Electrons Associated with Type III ...

    Indian Academy of Sciences (India)

    P. Kishore

    2017-06-19

    Jun 19, 2017 ... of the electron streams that generate type V bursts, spread in the velocity spectrum, and the curvature of the magnetic field lines along which they travel. Keywords. Sun—corona—magnetic field—flares—radio bursts—polarization. 1. Introduction. Type V bursts are relatively unusual solar radio tran- sients.

  15. Minaturized disk bend tests of neutron-irradiated path A type alloys

    International Nuclear Information System (INIS)

    Lee, M.; Sohn, D.S.; Grant, N.J.; Harling, O.K.

    1983-01-01

    Path A Prime Candidate Alloy (PCA) has been rapidly solidified and consoliated by extrusion. Twenty percent CW samples, precision TEM disks, 3 phi x 0.254 mm, were irradiated in the mixed flux of the Oak Ridge HFIR reactor up to approx. 8.5 dpa (360 appm He) and approx. 34 dpa (3100 appm He) at 300, 400, 500 and 600 0 C. Similar samples of conventionally processed PCA were also irradiated for comparison. Mechanical properties were characterized using a minaturized disk bend test (MDBT) developed at MIT. These tests indicate major decreases in strength and ductility especially for the 500 and 600 0 C irradiations. No major differences were found between this first version of a rapidly solidified and extruded PCA type alloy and conventionally processed PCA

  16. Magnetic orientation of paraffin in a magnetic levitation furnace

    Science.gov (United States)

    Takahashi, K.; Umeki, C.; Mogi, I.; Koyama, K.; Awaji, S.; Motokawa, M.; Watanabe, K.

    2004-04-01

    Containerless melting of paraffin under a magnetic levitation condition has been performed by using a cryogen-free hybrid magnet and two kinds of laser furnaces. One is local irradiation of CO 2 laser light at the top of the sample. The other is homogeneous irradiation of YAG laser light with a concave ring mirror. In the latter case, reduction of the Marangoni convection on the surface of the sample and the magnetic orientation of paraffin molecules were observed. The magnetic anisotropy of the spherical sample was confirmed by the measurement of magnetization and X-ray diffraction.

  17. Magnetic orientation of paraffin in a magnetic levitation furnace

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, K.; Umeki, C.; Mogi, I.; Koyama, K.; Awaji, S.; Motokawa, M.; Watanabe, K

    2004-04-30

    Containerless melting of paraffin under a magnetic levitation condition has been performed by using a cryogen-free hybrid magnet and two kinds of laser furnaces. One is local irradiation of CO{sub 2} laser light at the top of the sample. The other is homogeneous irradiation of YAG laser light with a concave ring mirror. In the latter case, reduction of the Marangoni convection on the surface of the sample and the magnetic orientation of paraffin molecules were observed. The magnetic anisotropy of the spherical sample was confirmed by the measurement of magnetization and X-ray diffraction.

  18. Magnetic orientation of paraffin in a magnetic levitation furnace

    International Nuclear Information System (INIS)

    Takahashi, K.; Umeki, C.; Mogi, I.; Koyama, K.; Awaji, S.; Motokawa, M.; Watanabe, K.

    2004-01-01

    Containerless melting of paraffin under a magnetic levitation condition has been performed by using a cryogen-free hybrid magnet and two kinds of laser furnaces. One is local irradiation of CO 2 laser light at the top of the sample. The other is homogeneous irradiation of YAG laser light with a concave ring mirror. In the latter case, reduction of the Marangoni convection on the surface of the sample and the magnetic orientation of paraffin molecules were observed. The magnetic anisotropy of the spherical sample was confirmed by the measurement of magnetization and X-ray diffraction

  19. Apparatus for irradiation with electron beam

    International Nuclear Information System (INIS)

    Uehara, K.; Ito, A.; Nishimune, K.; Fujita, K.

    1976-01-01

    An irradiation apparatus with high energy electrons is disclosed in which a wire shaped or linear object to be irradiated is moved back and forth many times under an electron window so as to irradiate it with an electron beam. According to one feature of the invention, an electron beam, which leaks through gaps between the objects to be irradiated or which penetrates the objects to be irradiated, is reversed by a magnetic field approximately perpendicular to the scanning face of the electron beam by means of a magnet which is disposed under the objects to be irradiated, and the reversed electron beam is thereby again applied to the objects to be irradiated. A high utilization rate of the electron beam is accomplished, and the objects can be thereby uniformly irradiated with the electron beam. 4 claims, 6 drawing figures

  20. Samarium-cobalt type rare earth permanent magnets

    International Nuclear Information System (INIS)

    Kamat, S.V.

    2014-01-01

    Permanent magnets are one of the oldest and largest applications of magnetic materials and form an integral part of our modern industrial society. They belong to a special class of functional materials and are characterized for remanence (flux output from the magnet), coercivity (resistance to demagnetization) and energy product (material energy density) from the second quadrant of the magnetic hysteresis loop. The reliability, stability, size, weight, cost and performance of many electro-technical devices depend mainly on the properties of permanent magnets used in them. There are three important families of permanent magnets viz., Ferrites, Alnicos and Rare Earth Permanent Magnets (REPMs) with energy product values ranging from 3 to 50 MGOe and among the front ranking high performance REPMs, SmCo 5 , Sm 2 Co 17 type and NdFeB alloys are technologically the most important materials. They are used in a wide range of applications ranging from consumer products to very specialized areas of tele-communications, microelectronics, defence, space, avionics etc. While NdFeB has the highest energy product, Sm-Co based magnets are preferred for most critical applications where temperature stability of magnetic properties is essential because of their significantly higher Curie temperatures. In this presentation some of the key challenges associated with these Sm-Co based rare earth permanent magnets will be highlighted. (author)

  1. Ce{sup 3+} incorporated structural and magnetic properties of M type barium hexaferrites

    Energy Technology Data Exchange (ETDEWEB)

    Pawar, R.A. [Department of Physics, Arts, Commerce and Science College, Satral, MS (India); Desai, S.S.; Tamboli, Q.Y. [Materials Research Laboratory, Shrikrishna Mahavidyalaya, Gunjoti 413613, MS (India); Shirsath, Sagar E. [Spin Device Technology Center, Faculty of Engineering, Shinshu University, Nagano 380-8553 (Japan); Patange, S.M., E-mail: smpatange@rediffmail.com [Materials Research Laboratory, Shrikrishna Mahavidyalaya, Gunjoti 413613, MS (India)

    2015-03-15

    M type barium hexaferrites BaCe{sub x}Fe{sub 12−x}O{sub 19} (0≤x≤0.3) (BCFO) were synthesized by the sol–gel auto combination method. Optimum annealing temperature of hexagonal phase was determined by using the TGA analysis. The annealing temperature form the TGA is 1000 °C samples annealed 1000 °C for 5 h to produce M type hexaferrites. X-ray diffraction data run to full Prof Program (Winploter 2010) pattern indicate that samples are single phase hexagonal structure with space group P6{sub 3}/mmc. Lattice parameter ‘a’ and ‘c’ increase with increase in Ce content x. Results of field emission scanning electron microscope show that the grains are regular hexagonal platelets with sizes from 0.3 to 1.4 μm. It is observed that from M–H curve value of the saturation magnetization and coercivity decreases with increasing x. Curie temperature from magnetization with temperature plot is found to decrease with Ce{sup 3+} substitution x due to decreases in magnetic interaction. - Highlights: • Ce{sup 3+} substituted Ba hexaferrites. • Increased coercivity with Ce{sup 3+} substitution. • Decrease in saturation magnetization and Curie temperature.

  2. Discontinuous spring magnet-type magnetostrictive Terfecohan/YFeCo multilayers: A novel nanostructured material principle for excellent magnetic softness

    International Nuclear Information System (INIS)

    Duc, N.H.; Huong Giang, D.T.

    2007-01-01

    Novel physics and reversal mechanisms of the whole system switching (WS) and individual switching (IS) type are reported for hard/soft TbFeCo/YFeCo exchange-spring multilayers. The WS type usually occurs in multilayered systems, in which the magnetic anisotropy of hard TbFeCo layers is neglectable. For such a system, the ferrimagnetically coupled hard/soft multilayered state is recovered after removing applied fields from the magnetized state. At low negative fields, the magnetization switching occurs collectively for all magnetic moments in the whole system. In this case, the low-coercivity mechanism is discussed on the basis of a hard/soft interfacial point contact. This configuration is realized for TbFeCo/YFeCo discontinuous exchange-spring multilayers, in which the magnetic (Fe,Co) nanograins coexist with non-magnetic amorphous phase in the soft layers. In this state, a magnetic coercivity as small as 0.4 mT is achieved. It is considered as an excellent magnetic softness of rare-earth-based systems. Enhancing the magnetic anisotropy in the hard TbFeCo layers, the magnetization switching follows the IS type at low temperatures. Starting to decrease the applied magnetic field from the high-field state, one observes the first reversal of the magnetic moments in the soft high-magnetization YFeCo-layers in positive magnetic fields. This is the reason for the observation of the negative coercivity as well as negative-biasing phenomena

  3. Registration properties of different types of CR-39 in vacuum conditions of irradiation

    International Nuclear Information System (INIS)

    Golovchenko, A.N.; Tret'yakova, S.P.

    1991-01-01

    Sensitivity change has been studied of different types of CR-39 detectors (Pershore, Tastrak, Intercast, Ma-ND/α) in dependence on holding time of detector in vacuum chamber at the residual pressure P ≅ 2x10 -2 and ≅ 5x10 -3 Pa before their irradiation with alpha particles from thin 238 Pu source and accelerated charged ions with atomic number Z=2-10 and energy of 9.1 MeV/nucleon. Polymer of Intercast Company turned out to be the most stable one to vacuum effect, and detector does not change the sensitivity up to response function REL 200 ≅ 1 MeVxcm 2 xmg -1 in the mentioned experiment conditions. 7 refs.; 3 figs

  4. Specification for switching magnets type S30, S45 and S60

    International Nuclear Information System (INIS)

    Cornell, J.C.

    1983-01-01

    This document specifies 3 types of symmetric, water-cooled dipole switching magnets, type S30 with a maximum bend angle of plus minus 30 0 type S45 with bend angles of +45 0 and -45 0 only and type S60 with bend angles up to plus minus 60 0 . One magnet of each type will be required. These magnets will form part of the beam distribution system for the 200 MeV separated-sector cyclotron at the National Accelerator Centre of the Council for Scientific and Industrial Research at Faure

  5. Mechanical-property changes of structural composite materials after low-temperature proton irradiation: Implications for use in SSC magnet systems

    International Nuclear Information System (INIS)

    Morena, J.; Snead, C.L. Jr.; Czajkowski, C.; Skaritka, J.

    1993-01-01

    Longterm physical, mechanical, electrical, and other properties of advanced composites, plastics, and other polymer materials are greatly affected by high-energy proton, neutron, electron, and gamma radiation. The effects of high-energy particles on materials is a critical design parameter to consider when choosing polymeric structural, nonstructural, and elastomeric matrix resin systems. Polymer materials used for filled resins, laminates, seals, gaskets, coatings, insulation and other nonmetallic components must be chosen carefully, and reference data viewed with caution. Most reference data collected in the high-energy physics community to date reflects material property degradation using other than proton irradiations. In most instances, the data were collected for room-temperature irradiations, not 4.2 K or other cryogenic temperatures, and at doses less than 10 8 --10 9 Rad. Energetic proton (and the accompanying spallation-product particles) provide good simulation fidelity to the expected radiation fields predicted for the cold-mass regions of the SSC magnets, especially the corrector magnets. The authors present here results for some structural composite materials which were part of a larger irradiation-characterization of polymeric materials for SSC applications

  6. UVΑ pre-irradiation to P25 titanium dioxide nanoparticles enhanced its toxicity towards freshwater algae Scenedesmus obliquus.

    Science.gov (United States)

    Roy, Barsha; Chandrasekaran, Hemamalini; Palamadai Krishnan, Suresh; Chandrasekaran, Natarajan; Mukherjee, Amitava

    2018-04-02

    There has recently been an increase in the usage of TiO 2 nanoparticles (NPs). P25 TiO 2 NPs, a mixture of anatase and rutile phase in 3:1 ratio, are generally used for photocatalytic applications because both phases exhibit a synergistic effect on the photocatalytic activity of the TiO 2 NPs. In the present study, increased toxicity of UVA-pre-irradiated P25 TiO 2 NPs on freshwater algae Scenedesmus obliquus was assessed under visible light and dark exposure conditions at actual low concentrations (0.3, 3 and 35 μM of Ti). Photocatalytic property of P25 TiO 2 NPs caused disaggregation of UVA-pre-irradiated NPs, thus significantly decreasing the mean hydrodynamic diameter (MHD) (188.74 ± 0.54 nm) than that of non-irradiated NPs (232.26 ± 0.44). This decrease in diameter of UVA-pre-irradiated NPs may increase its biological activity towards algal samples. All concentrations of pre-irradiated NPs, under both light and dark conditions, showed a significantly lesser cell viability (p effects of UVA-pre-irradiated TiO 2 NPs on freshwater algae, thereby emphasising the need for ecological risk assessments of metal oxide nanoparticles in a natural experimental medium.

  7. Irradiation-induced doping of Bismuth Telluride Bi2Te3

    International Nuclear Information System (INIS)

    Rischau, Carl Willem

    2014-01-01

    Bismuth Telluride Bi 2 Te 3 has attracted enormous attention because of its thermoelectric and topological insulator properties. Regarding its bulk band structure Bi 2 Te 3 is a band insulator with an energy gap of around 150-170 meV. However, the native anti-site defects that are present in real samples always dope this band insulator and shift the chemical potential into the valence or conduction band. In this PhD, the Fermi surface of as-grown and electron irradiated p-type Bi 2 Te 3 single crystals has been investigated extensively using electrical transport experiments. For moderate hole concentrations (p ∼< 5 x 10 18 cm -3 ), it is confirmed that electrical transport can be explained by a six-valley model and the presence of strong Zeeman-splitting. At high doping levels (p≅5 x 10 18 cm -3 ), the hole concentrations determined from Hall and Shubnikov-de Haas (SdH) effect differ significantly which is attributed to an impurity/defect band introduced by the anti-site defects. In this work, we show that it is possible to dope p-type Bi 2 Te 3 in a very controlled manner using electron-irradiation by performing detailed in- and ex-situ electrical transport studies on samples irradiated at room and at low temperatures with 2.5 MeV electrons. These studies show that the defects induced at both irradiation temperatures act as electron donors and can thus be used to convert the conduction from p- to n-type. The point of optimal compensation is accompanied by an increase of the low-temperature resistivity by several orders of magnitude. Irradiation at room temperature showed that both the p-type samples obtained after irradiation to intermediate doses as well as the samples in which the conduction has been converted to n-type by irradiation, still have a well defined Fermi surface as evidenced by SdH oscillations. By studying the Hall coefficient in-situ during low temperature electron irradiation, the coexistence of electron- and hole-type carriers was evidenced

  8. Compact ILU-type electron accelerators as a base for industrial 4-sided irradiation systems for cable and tubes

    International Nuclear Information System (INIS)

    Auslender, V.L.; Nekhaev, V.E.; Panfilov, A.D.; Tuvik, A.A.

    1999-01-01

    The ILU-type industrial electron accelerators are developed in BINP sins 1967. Their energy range is 0.7-4.0 MeV at beam power of 20-50 kW. The comparison of the irradiation results after bilateral and four-sided irradiation of cables and tubes is given. It is shown that the required electron energy and beam power in the case of four-sided irradiation are sufficiently lower than in the case of bilateral irradiation, resulting in an increase of productive rate of the process and improvement of treatment quality. The installations for four-sided irradiation of cables and tubes are based on the industrial electron accelerators type ILU

  9. Magnetism of the spin-trimer compound CaNi 3(P 2O 7)2: Microscopic insight from combined 31P NMR and first-principles studies

    Science.gov (United States)

    Majumder, M.; Kanungo, S.; Ghoshray, A.; Ghosh, M.; Ghoshray, K.

    2015-03-01

    Magnetization, 31P nuclear magnetic resonance study, and first-principles electronic structure calculations have been performed in the spin-1 trimer chain compound CaNi3(P2O7 )2. Two separate spectra arising from magnetically and crystallographically inequivalent P sites are observed. In the ordered state, the resonance lines for both the P sites (P1 and P2) are found to be split into two, which is clear microscopic evidence of the development of two-sublattice AFM order below TM. A nonnegligible contribution of ferromagnetic hyperfine field and dipolar field have also been seen in the ordered state. The first-principles calculations show that the intratrimer (J1) and intertrimer interactions (J2) are of weak ferromagnetic type with the values 2.85 and 1.49 meV, respectively, whereas the interchain interaction (J3) is of strong antiferromagnetic type with a value of 5.63 meV. The anisotropy of the imaginary part of dynamical spin susceptibility around TM along with the exponential decrement of 1 /T1 below TM indicate the probable participation of the Ni -3 d electron's orbital degrees of freedom in the ferrimagnetic transition. The dominance of orbital fluctuations over the spin fluctuations seems to be responsible for showing low value of the binding energy u of the local spin configuration (estimated from local spin models) and an unusually weak exponent in the power-law behavior of 1 /T1 below 50 K, in the paramagnetic state. Electronic structure calculations also reveal the importance of orbital degrees of freedom of Ni -3 d moments, which is consistent with our NMR data analysis.

  10. Visualizing the photovoltaic behavior of a type-II p-n heterojunction superstructure

    Energy Technology Data Exchange (ETDEWEB)

    Xing, Juanjuan, E-mail: xingjuanjuan@mail.sic.ac.cn [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China); Electron Microscopy Group, Surface Physics and Structure Unit, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Takeguchi, Masaki [Electron Microscopy Group, Surface Physics and Structure Unit, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Hashimoto, Ayako [Electron Microscopy Group, Surface Physics and Structure Unit, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Global Research Center for Environment and Energy Based on Nanomaterials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Cao, Junyu; Ye, Jinhua [International Center for Materials Nanoarchitectonics (WPI-MANA), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

    2014-04-21

    Photovoltaic behavior of a CaFe{sub 2}O{sub 4}/ZnFe{sub 2}O{sub 4} p-n multi-junction was investigated with electron holography combined with an in situ light irradiation system. Potential profiles of the samples with and without light irradiation were extracted to measure the open circuit photovoltage generated either by the whole heterojunction superstructure or from each p-n junction. Investigation on the variation in the energy band configuration under light irradiation revealed the mechanism involved in the photoelectric effect, with respect to the properties of the heterojunction and its periodic quantum structure.

  11. Coprecipitation of M23C6 and MC type carbide under the influence of irradiation

    International Nuclear Information System (INIS)

    Kesternich, W.; Nandedkar, R.V.

    1991-01-01

    After high-temperature neutron irradiation of 1.4970 type steel, M 23 C 6 precipitation was observed in the matrix. This precipitate phase was found only at grain boundaries after thermal treatments. A unique feature of this irradiation-modified phase formation was that the M 23 C 6 precipitates nucleated at the surfaces of pre-existing MC type carbides and grew in a very unusual way by forming facetted enclosures around the primary precipitates. (orig.)

  12. Stability of the post irradiation traps in LiF: Mg, Cu, P

    International Nuclear Information System (INIS)

    Gonzalez, P.R.; Furetta, C.; Azorin, J.

    2004-01-01

    In this work the results of the study of the stability of the traps are presented in dosemeters Tl of LiF: Mg,Cu,P, irradiated with gamma radiation of 60 Co. The studied dosemeters were of LiF: Mg,Cu,P + Ptfe, developed in the ININ, taking like reference to the commercial dosemeter GR200A of Chinese manufacture. Before being exposed to the radiation, the dosemeters received their standard treatment from having erased, two hours after the irradiation they took the initial readings. The dosemeters faded again and they were irradiated to the same dose, soon after they stayed under normal conditions, protected of the light, later on they were taken their readings periodically during six months. The readings taken Tl the same day of the irradiation presented four peaks whose energy, determined by the deconvolution method were; 1.30 ± 0.01 eV, 1.50 ± 0.01 eV, 1.70 ± 0.01 eV and 2.58 ± 0.02 eV, for LiF: Mg,Cu,P + Ptfe, while GR200A stops the energy they were: 1.33 ± 0.11 eV, 1.58 ± 0.11 eV, 1.73 ± 0.11 eV and 2.60 ± 0.03 eV. In both cases the peak 1, with the energy but it lowers, it disappears completely after some later hours to the irradiation, while the peak 2, it disappears completely after 122 days for the local dosemeter and after 94 days for the commercial dosemeter. The energy of the peaks 3 and 4 that remained visible during the whole period of study it was: 1.38 ± 0.01 eV and 2.65 ± 0.01 eV, for LiF: Mg,Cu,P + Ptfe respectively, in the same order for GR200A, the energies were: 1.51 ± 0.02 eV and 2.64 ± 0.03 eV. In all the cases the peaks with energy below 2 eV, showed tendency to the drop, while the main peak, showed certain tendency to increase, as they show it the results. (Author)

  13. Construction of recombinant plasmid pIRESEgr-IFN γ and its expression in Lewis lung carcinoma induced by irradiation

    International Nuclear Information System (INIS)

    Yang Wei; Li Xiuyi; Gong Shouliang; Sun Ting; Gong Pingsheng

    2007-01-01

    Objective: To construct the recombinant plasmid pIRESEgr-IFN γ and detect its expression in Lewis lung carcinoma induced by irradiation in vitro. Methods: The recombinant plasmid pIRESEgr-IFN γ containing Egr-1 promoter and IFN γ gene was constructed with gene recombinant technique. The plasmid was transferred into Lewis lung carcinoma by liposome in vitro. The correlations of dose- and time-effects in the expression of IFN γ gene induced by X-ray were detected by ELISA. Results: The identification with enzymes proved that Egr-1 promoter and IFN γ gene were inserted into vector pIRESlneo correctly. After X-ray irradiation with different doses, the expression of IFN γ in the supernatant of Lewis lung carcinoma transfected by pIRESEgr-IFN γ was significantly higher than that in 0 Gy group (P<0.001). After 5 Gy X-ray irradiation, the expression of IFN γ was the highest, being 4.39 times as much as that in 0 Gy group. The expression of IFN γ in the supernatant increased after 5 Gy X-ray irradiation, being 6.27 times as much as that in 0 h group 36 h after irradiation. Conclusion: The recombinant plasmid pIRESEgr-IFN γ is constructed successfully, and it has the property of enhancing the expression of IFN γ gene induced by irradiation. (authors)

  14. Electrically active defects in p-type silicon after alpha-particle irradiation

    Science.gov (United States)

    Danga, Helga T.; Auret, F. Danie; Tunhuma, Shandirai M.; Omotoso, Ezekiel; Igumbor, Emmanuel; Meyer, Walter E.

    2018-04-01

    In this work, we investigated the defects introduced when boron (B) doped silicon (Si) was irradiated by making use of a 5.4 MeV americium (Am) 241 foil radioactive source with a fluence rate of 7×106 cm-2 s-1 at room temperature. Deep level transient spectroscopy (DLTS) and Laplace-DLTS measurements were used to investigate the electronic properties of the introduced defects. After exposure at a fluence of 5.1×1010 cm-2, the energy levels of the hole traps measured were: H(0.10), H(0.16), H(0.33) and H(0.52) The defect level H(0.10) was tri-vacancy related. H(0.33) was identified as the interstitial carbon (Ci) related defect which was a result of radiation induced damage. H(0.52) was a B-related defect. Explicit deductions about the origin of H(0.16) have not yet been achieved.

  15. Structural analysis on the open basket type instrumented capsule for fuel irradiation tests in HANARO

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Do Sik; Kang, Y. H.; Kim, B. G.; Cho, M. S.; Sohn, J. M.; Choo, K. N.; Oh, J. M.; Shin, Y. T.; Park, S. J. [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2002-05-01

    To develop the open basket type instrumented capsule to be used for the irradiation test of various nuclear fuels, it is necessary to ensure the compatibility of the capsule with HANARO and the structural integrity of the capsule. The dimensions of the open basket type instrumented capsule were determined in the basis of the pressure drop criteria in OR test hole of HANARO(mass flow rate <12.7kg/s, pressure drop {delta}P>200kPa). From the buckling stability analysis for this capsule, the critical buckling load P{sub cr} was 7.5kN. The vertical impact stress of the capsule under unit impact load was evaluated by the transient analysis, and the maximum vertical impact load calculated from the impact stress and the allowable stress was 60.5kN. Under the loading of the calculated Pcr, the maximum vertical impact stress was 20.4MPa. The structural integrity of the capsule under a horizontal impact loading was also examined. The mechanical stresses occurred by the pressure difference at the inner and outer surface of cladding and by the coolant pressure at the surface of cladding were 3.1MPa and 43.3MPa, respectively. These stress values were lower than the allowable stress in each case. Therefore, it was ensured that the instrumented capsule for the irradiation test of various nuclear fuels met the criteria on the structural integrity during installing and testing the capsule in HANARO. 8 refs., 61 figs., 3 tabs. (Author)

  16. Fracture toughness and stress relief response of irradiated Type 347/348 stainless steel

    International Nuclear Information System (INIS)

    Haggag, F.M.

    1985-01-01

    A test program has experimentally determined: (1) The fracture toughness of Type 347/348 stainless steel (SS) specimens with high values of irradiation fluence (2.3 to 4.8 x 10 22 n/cm 2 , E > 1.0 MeV) and experiencing different levels of irradiation creep (0.0, 0.6, 1.1, 1.8%), (2) the effect of thermal stress relief on fracture toughness recovery for the highly irradiated material, and (3) the mechanisms associated with fracture toughness recovery due to thermal stress relief. The postirradiation fracture toughness tests and tensile tests were conducted at 427 0 C

  17. A new type of permanent magnet ondulator and wiggler

    International Nuclear Information System (INIS)

    Jianming, X.; Maosan, L.; Qing, X.

    1987-01-01

    A new type of permanent magnet ondulator and wiggler is discussed. In this new design the magnet is composed of permanent magnet segments with modulated thickness. The magnetization directions of the segments are all perpendicular to the symmetrical plane of the magnet gap. By modulating the thicknesses of the segments, the field distribution is a pure sinusoidal curve in the ideal 2-dimensional case. The spatial expressions of the magnet field in the ideal case and in the real case are given. The methods for reducing the undesirable harmonics in the magnet field in the real case are discussed. Because of the arrangement of the magnetization directions of the magnet segments, soft iron shield can be used to strenghten the magnet field. In some cases, the stregnthening factor is more than two. The strenghtening effect of the soft iron shield is analysed also

  18. Magneto-transport phenomena in metal/SiO2/n(p)-Si hybrid structures

    Science.gov (United States)

    Volkov, N. V.; Tarasov, A. S.; Rautskii, M. V.; Lukyanenko, A. V.; Bondarev, I. A.; Varnakov, S. N.; Ovchinnikov, S. G.

    2018-04-01

    Present review touches upon a subject of magnetotransport phenomena in hybrid structures which consist of ferromagnetic or nonmagnetic metal layer, layer of silicon oxide and silicon substrate with n- or p-type conductivity. Main attention will be paid to a number gigantic magnetotransport effects discovered in the devices fabricated on the base of the M/SiO2/n(p)-Si (M is ferromagnetic or paramagnetic metal) hybrid structures. These effects include bias induced dc magnetoresistance, gigantic magnetoimpedance, dc magnetoresistance induced by an optical irradiation and lateral magneto-photo-voltaic effect. The magnetoresistance ratio in ac and dc modes for some of our devices can exceed 106% in a magnetic field below 1 T. For lateral magneto-photo-voltaic effect, the relative change of photo-voltage in magnetic field can reach 103% at low temperature. Two types of mechanisms are responsible for sensitivity of the transport properties of the silicon based hybrid structures to magnetic field. One is related to transformation of the energy structure of the (donor) acceptor states including states near SiO2/n(p)-Si interface in magnetic field. Other mechanism is caused by the Lorentz force action. The features in behaviour of magnetotransport effects in concrete device depend on composition of the used structure, device topology and experimental conditions (bias voltage, optical radiation and others). Obtained results can be base for design of some electronic devices driven by a magnetic field. They can also provide an enhancement of the functionality for existing sensors.

  19. 2 MeV, 60 kW dual-beam type electron accelerator irradiation facility

    International Nuclear Information System (INIS)

    Yotsumoto, Keiichi; Kanazawa, Takao; Haruyama, Yasuyuki; Agematsu, Takashi; Mizuhashi, Kiyoshi; Sunaga, Hiromi; Washino, Masamitsu; Tamura, Naoyuki

    1984-02-01

    The specification of new irradiation facility which has been constructed from 1978 through 1981 as the replacement of 1st Accelerator of JAERI, TRCRE are described. The accelerator is the Cockcroft-Walton type and both vertical and horizontal accelerating tubes are arranged on a single high voltage generator. Transferring of the high voltage to the horizontal accelerating tube is performed with the high voltage changing system in the pressure vessel. The output ratings of the accelerator are 2 MV of acceleration voltage and 30 mA of beam current. By providing the dual beam system, two irradiation rooms, one for vertical and the other for horizontal beam, are independently operationable. Persons can enter the horizontal irradiation room for experimental setting even when the vertical irradiation room is in operation. The specification of the buildings, the exhaust air treatment system, the irradiation conveyor and the safety observation system are also described. (author)

  20. SU-D-304-02: Magnetically Focused Proton Irradiation of Small Field Targets

    International Nuclear Information System (INIS)

    McAuley, GA; Slater, JM; Slater, JD; Wroe, AJ

    2015-01-01

    Purpose: To investigate the use of magnetic focusing for small field proton irradiations. It is hypothesized that magnetic focusing will provide significant dose distribution benefits over standard collimated beams for fields less than 10 mm diameter. Methods: Magnets consisting of 24 segments of radiation hard samarium-cobalt adhered into hollow cylinders were designed and manufactured. Two focusing magnets were placed on a positioning track on our Gantry 1 treatment table. Proton beams with energies of 127 and 157 MeV, 15 and 30 mm modulation, and 8 mm initial diameters were delivered to a water tank using single-stage scattering. Depth dose distributions were measured using a PTW PR60020 diode detector and transverse profiles were measured with Gafchromic EBT3 film. Monte Carlo simulations were also performed - both for comparison with experimental data and to further explore the potential of magnetic focusing in silica. For example, beam spot areas (based on the 90% dose contour) were matched at Bragg depth between simulated 100 MeV collimated beams and simulated beams focused by two 400 T/m gradient magnets. Results: Preliminary experimental results show 23% higher peak to entrance dose ratios and flatter spread out Bragg peak plateaus for 8 mm focused beams compared with uncollimated beams. Monte Carlo simulations showed 21% larger peak to entrance ratios and a ∼9 fold more efficient dose to target delivery compared to spot-sized matched collimated beams. Our latest results will be presented. Conclusion: Our results suggest that rare earth focusing magnet assemblies could reduce skin dose and beam number while delivering dose to nominally spherical radiosurgery targets over a much shorter time compared to unfocused beams. Immediate clinical applications include those associated with proton radiosurgery and functional radiosurgery of the brain and spine, however expanded treatment sites can be also envisaged

  1. SU-D-304-02: Magnetically Focused Proton Irradiation of Small Field Targets

    Energy Technology Data Exchange (ETDEWEB)

    McAuley, GA; Slater, JM [Loma Linda University, Loma Linda, CA (United States); Slater, JD; Wroe, AJ [Loma Linda University Medical Center, Loma Linda, CA (United States)

    2015-06-15

    Purpose: To investigate the use of magnetic focusing for small field proton irradiations. It is hypothesized that magnetic focusing will provide significant dose distribution benefits over standard collimated beams for fields less than 10 mm diameter. Methods: Magnets consisting of 24 segments of radiation hard samarium-cobalt adhered into hollow cylinders were designed and manufactured. Two focusing magnets were placed on a positioning track on our Gantry 1 treatment table. Proton beams with energies of 127 and 157 MeV, 15 and 30 mm modulation, and 8 mm initial diameters were delivered to a water tank using single-stage scattering. Depth dose distributions were measured using a PTW PR60020 diode detector and transverse profiles were measured with Gafchromic EBT3 film. Monte Carlo simulations were also performed - both for comparison with experimental data and to further explore the potential of magnetic focusing in silica. For example, beam spot areas (based on the 90% dose contour) were matched at Bragg depth between simulated 100 MeV collimated beams and simulated beams focused by two 400 T/m gradient magnets. Results: Preliminary experimental results show 23% higher peak to entrance dose ratios and flatter spread out Bragg peak plateaus for 8 mm focused beams compared with uncollimated beams. Monte Carlo simulations showed 21% larger peak to entrance ratios and a ∼9 fold more efficient dose to target delivery compared to spot-sized matched collimated beams. Our latest results will be presented. Conclusion: Our results suggest that rare earth focusing magnet assemblies could reduce skin dose and beam number while delivering dose to nominally spherical radiosurgery targets over a much shorter time compared to unfocused beams. Immediate clinical applications include those associated with proton radiosurgery and functional radiosurgery of the brain and spine, however expanded treatment sites can be also envisaged.

  2. Admittance studies of neutron-irradiated silicon p+-n diodes

    International Nuclear Information System (INIS)

    Tokuda, Y.; Usami, A.

    1977-01-01

    Defects introduced in n-type silicon by neutron irradiation were investigated by measuring the conductance (G) and the capacitance (C) of p + -n diodes. The method of the determination of the energy level, capture cross section, and concentration for each defect from the G-T and C-T curves for various frequencies was presented. Assuming that capture cross sections are independent of temperature, the energy levels of E/sub c/-0.15 eV, E/sub c/-0.22 eV, and E/sub c/-0.39 eV were obtained. For these defects, the calculated values of the electron capture cross section were 2.6 x 10 -14 , 3.7 x 10 -15 , and 2.0 x 10 -14 cm 2 , respectively. The introduction rate of defects for E/sub c/-0.39 eV was twice that for E/sub c/-0.22 eV which was twice that for E/sub c/-0.15 eV. Comparing with other published data, the energy levels of E/sub c/-0.15 eV and E/sub c/-0.39 eV were found to be correlated with the A center and the divacancy, respectively

  3. Systematization of types and methods of radiation therapy methods and techniques of irradiation of patients

    International Nuclear Information System (INIS)

    Vajnberg, M.Sh.

    1991-01-01

    The paper is concerned with the principles of systematization and classification of types and methods of radiation therapy, approaches to the regulation of its terminology. They are based on the distinction of the concepts of radiation therapy and irradiation of patients. The author gives a consice historical review of improvement of the methodology of radiation therapy in the course of developing of its methods and facilities. Problems of terminology are under discussion. There is a table of types and methods of radiation therapy, methods and techniques of irradiation. In the appendices one can find a table of typical legends and examples of graphic signs to denote methods of irradiation. Potentialities of a practical use of the system are described

  4. Effect of elastic deformation and the magnetic field on the electrical conductivity of p-Si crystals

    Science.gov (United States)

    Lys, R.; Pavlyk, B.; Didyk, R.; Shykorjak, J.; Karbovnyk, I.

    2018-03-01

    It is shown that at a deformation rate of 0.41 kg/min, the characteristic feature of the dependence of the surface resistance of the p-Si sample on the magnitude of its elastic deformation (R(σ)) is the reduction of the resistance during compression and unclamping. With the increase in the number of "compression-unclamping" cycles, the difference between the positions of the compression and unclamping curves decreases. The transformation of two types of magnetically sensitive defects occurs under the impact of a magnetic field on p-Si crystals. The defects are interrelated with two factors that cause the mutually opposite influence on the conductivity of the crystal. The first factor is that the action of the magnetic field decreases the activation energy of the dislocation holders, which leads to an increase in the electrical conductivity of the sample. The second factor is that due to the decay of molecules of oxygen-containing impurities in the magnetic field, the stable chemisorption bonds appear in the crystal that leads to a decrease in its conductivity. If the sample stays in the magnetic field for a long time, the one or the other mechanism predominates, causing a slow growth or decrease in resistance around a certain (averaged) value. Moreover, the frequency of such changes is greater in the deformed sample. The value of the surface resistance of p-Si samples does not change for a long time without the influence of the magnetic field.

  5. Effect of γ-rays irradiation on the structural, magnetic, and electrical properties of Mg–Cu–Zn and Ni–Cu–Zn ferrites

    Energy Technology Data Exchange (ETDEWEB)

    Assar, S.T.; Abosheiasha, H.F., E-mail: Hatem_fouad@f-eng.tanta.edu.eg; El Sayed, A.R.

    2017-01-01

    Nanoparticles of Ni{sub 0.35}Cu{sub 0.15}Zn{sub 0.5}Fe{sub 2}O{sub 4} and Mg{sub 0.35}Cu{sub 0.15}Zn{sub 0.5}Fe{sub 2}O{sub 4}, have been synthesized by citrate precursor method. Then some of the prepared samples have been irradiated by γ-rays of {sup 60}Co radioactive source at room temperature with doses of 1 Mrad and 2 Mrad, at a dose rate of 0.1 Mrad/h to study the effect of γ-rays irradiation on some structural, magnetic and electrical properties of the samples. The X-ray diffraction analysis (XRD), transmission electron microscopy, Fourier transform infrared spectroscopy and vibrating sample magnetometer measurements have been used to investigate the samples. The XRD results show that the irradiation has caused a decrease in the crystallite size and the measured density and an increase in the porosity, specific surface area, and microstrain in the case of Ni–Cu–Zn ferrite whereas in the case of Mg–Cu–Zn ferrite the reverse trend has been noticed. The lattice constant of the investigated samples has been increased with the increase of irradiation due to the conversion of Fe{sup 3+} (0.67 Å) to Fe{sup 2+} (0.76 Å). The magnetization results show an increase in saturation and remnant magnetizations for the two prepared ferrites after γ-rays irradiation. The main reason of this behavior is most probably due to the redistribution of the cations between A and B sites. The cation distribution has been proposed such that the values of theoretical and experimental magnetic moment are identical and increase as the magnetization increases. Moreover, a theoretical estimation of the lattice constant has been calculated on the basis of the proposed cation distribution for each sample and compared with the corresponding experimental values obtained by XRD analysis; where they have been found in a good agreement with each other. This can be considered as another confirmation of the validity of the cation distribution. Moreover, the cation distribution is thought

  6. Effects of helium content of microstructural development in Type 316 stainless steel under neutron irradiation

    International Nuclear Information System (INIS)

    Maziasz, P.J.

    1985-11-01

    This work investigated the sensitivity of microstructural evolution, particularly precipitate development, to increased helium content during thermal aging and during neutron irradiation. Helium (110 at. ppM) was cold preinjected into solution annealed (SA) DO-heat type 316 stainess steel (316) via cyclotron irradiation. These specimens were then exposed side by side with uninjected samples. Continuous helium generation was increased considerably relative to EBR-II irradiation by irradiation in HFIR. Data were obtained from quantitative analytical electron microscopy (AEM) in thin foils and on extraction replicas. 480 refs., 86 figs., 19 tabs

  7. Effects of helium content of microstructural development in Type 316 stainless steel under neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Maziasz, P.J.

    1985-11-01

    This work investigated the sensitivity of microstructural evolution, particularly precipitate development, to increased helium content during thermal aging and during neutron irradiation. Helium (110 at. ppM) was cold preinjected into solution annealed (SA) DO-heat type 316 stainess steel (316) via cyclotron irradiation. These specimens were then exposed side by side with uninjected samples. Continuous helium generation was increased considerably relative to EBR-II irradiation by irradiation in HFIR. Data were obtained from quantitative analytical electron microscopy (AEM) in thin foils and on extraction replicas. 480 refs., 86 figs., 19 tabs.

  8. Nanocomposite permanent magnetic materials Nd-Fe-B type: The influence of nanocomposite on magnetic properties

    Directory of Open Access Journals (Sweden)

    Talijan Nadežda M.

    2005-01-01

    Full Text Available The influence on the magnetic properties of nanocristalline ribbons and powders has character of microstructure, between others – the grain size volume of hard and soft magnetic phases and their distribution. Magnetic properties of ribbons and powders depend mainly on their chemical composition and parameters of their heat treatment [1]. Technology of magnets from nanocristalline ribbon consists of the following process: preparing the Nd-Fe- B alloy, preparing the ribbon, powdering of the ribbon, heat treatment of the powder and finally preparing the magnets. Nanocomposite permanent magnet materials based on Nd-Fe- B alloy with Nd low content are a new type of permanent magnetic material. The microstructure of this nanocomposite permanent magnet is composed of a mixture of magnetically soft and hard phases which provide so called exchange coupling effect.

  9. Application of magnetic circular dichroism spectroscopy to the optical spectra of natural and irradiated diamonds

    International Nuclear Information System (INIS)

    Douglas, I.N.; Ruciman, W.A.; Australian National Univ., Canberra. Research School of Physical Sciences)

    1977-01-01

    The MCD spectra of natural type Ia and electron-irradiated type Ia and type IIa diamonds have been measured. The information obtained from MCD spectroscopy complements that obtained from absorption spectroscopy and can be helpful in the assignment of electronic transitions. (orig.) [de

  10. Performance Comparison of Permanent Magnet Linear Actuators of Different Mover Types

    DEFF Research Database (Denmark)

    Ritchie, Ewen; Hinov, K.; Yatchev, I.

    2006-01-01

    A comparative study of permanent magnet linear actuators with different location of the permanent magnet is reported. Three mover types are considered - soft magnetic mover, permanent magnet mover and hybrid mover. Force-stroke characteristics are obtained with the help of finite element models...

  11. Gamma-ray irradiation and post-irradiation at room and elevated temperature response of pMOS dosimeters with thick gate oxides

    Directory of Open Access Journals (Sweden)

    Pejović Momčilo M.

    2011-01-01

    Full Text Available Gamma-ray irradiation and post-irradiation response at room and elevated temperature have been studied for radiation sensitive pMOS transistors with gate oxide thickness of 100 and 400 nm, respectively. Their response was followed based on the changes in the threshold voltage shift which was estimated on the basis of transfer characteristics in saturation. The presence of radiation-induced fixed oxide traps and switching traps - which lead to a change in the threshold voltage - was estimated from the sub-threshold I-V curves, using the midgap technique. It was shown that fixed oxide traps have a dominant influence on the change in the threshold voltage shift during gamma-ray irradiation and annealing.

  12. Radiation damage structure in irradiated and annealed 440 WWER-Type reactor pressure vessel steels

    International Nuclear Information System (INIS)

    Kocik, J.; Keilova, E.

    1993-01-01

    A review of irradiation damages in WWER-type RPV steels based on conventional Transmission Electron Microscopy investigations in a power reactor and a research reactor, is presented; the samples consist in Cr-Mo-V ferritic steel (15Kh2MFA type). The visible part of radiation-induced defects consists of very fine vanadium carbide precipitates, small dislocation loops and black dots (presumably corresponding to clusters and particle embryos formed from vacancies and solute-atoms (vanadium, copper, phosphorus) and carbon associated with vanadium. Radiation-induced defects are concentrated at dislocation substructure during irradiation in a power reactor, revealing the role of radiation-enhanced diffusion in damage structure forming process. Contrarily, the distribution of defects resulting from annealing of specimens irradiated in the research reactor is pre-determined by an homogenous distribution of radiation-induced defects prior to annealing. Increasing the number of re-irradiation and annealing cycles, the amount of dislocation loops among all defects seems to be growing. Simultaneously, the dislocation substructure recovers considerably. (authors). 14 refs., 11 figs., 3 tabs

  13. Radiation damage structure in irradiated and annealed 440 WWER-Type reactor pressure vessel steels

    Energy Technology Data Exchange (ETDEWEB)

    Kocik, J; Keilova, E [Czech Nuclear Society, Prague (Czech Republic)

    1994-12-31

    A review of irradiation damages in WWER-type RPV steels based on conventional Transmission Electron Microscopy investigations in a power reactor and a research reactor, is presented; the samples consist in Cr-Mo-V ferritic steel (15Kh2MFA type). The visible part of radiation-induced defects consists of very fine vanadium carbide precipitates, small dislocation loops and black dots (presumably corresponding) to clusters and particle embryos formed from vacancies and solute-atoms (vanadium, copper, phosphorus) and carbon associated with vanadium. Radiation-induced defects are concentrated at dislocation substructure during irradiation in a power reactor, revealing the role of radiation-enhanced diffusion in damage structure forming process. Contrarily, the distribution of defects resulting from annealing of specimens irradiated in the research reactor is pre-determined by an homogenous distribution of radiation-induced defects prior to annealing. Increasing the number of re-irradiation and annealing cycles, the amount of dislocation loops among all defects seems to be growing. Simultaneously, the dislocation substructure recovers considerably. (authors). 14 refs., 11 figs., 3 tabs.

  14. Graphene supported silver@silver chloride & ferroferric oxide hybrid, a magnetically separable photocatalyst with high performance under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Suting; Jiang, Wei, E-mail: superfine_jw@126.com; Han, Mei; Liu, Gongzong; Zhang, Na; Lu, Yue

    2015-08-30

    Graphical abstract: - Highlights: • The composites were synthesized via a facile and effective process. • Plenty of Fe{sub 3}O{sub 4} and Ag@AgCl nanoparticles are deposited on the reduced graphene oxide nanosheets. • The catalyst exhibited an enhanced photocatalytic performance and magnetic property. • The catalyst is stable under the visible light irradiation. - Abstract: A stable magnetic separable plasmonic photocatalyst was successfully fabricated by grafting silver@silver chloride (Ag@AgCl) and ferroferric oxide (Fe{sub 3}O{sub 4}) nanoparticles on graphene sheets. The composite exhibited high activity degrading methylene blue (MB) and rhodamine B (RB) under visible light irradiation: decomposition 97.4% of MB in 100 min and 97.9% of RB in 120 min. The enhanced photocatalytic activities can be attributed to synergistic effect between Ag@AgCl and graphene: the effective charge transfer from Ag@AgCl to graphene thus promotes the separation of electron–hole pairs. Moreover, the excellent magnetic property gives a more convenient way to recycle the photocatalysts.

  15. Preparation and influence of pH on the dynamic magnetic property of magnetic FeCoC films

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Hongmei; Wei, Jinwu; Zhu, Zengtai; Cao, Derang; Liu, Qingfang [Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou 730000 (China); Wang, Jianbo, E-mail: wangjb@lzu.edu.cn [Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou 730000 (China); Key Laboratory for Special Function Materials and Structural Design of the Ministry of the Education, Lanzhou University, Lanzhou 730000 (China)

    2016-07-01

    FeCoC films were successfully prepared by electrochemical deposition method in different citric acid concentrations and pH values. The morphology, structure and magnetic properties were investigated. FeCoC films deposited at different citric acid concentrations have good soft magnetic performance. As the pH value increases from 2.49 to 6.02, the atomic ratio of Fe:Co range from 0.72 to 0.95. The coercivities of the films deposited at different pH values first increase and then decrease with increasing pH. The resonance frequency of the films can be tuned by controlling the pH value, and in an appropriate pH value a wide absorption peak can be obtained. - Highlights: • We have successfully prepared FeCoC soft magnetic films by electrochemical deposition method. • The resonance frequency can be controlled by changing pH value. • A widely absorption peak will be obtained when the pH value is appropriate.

  16. Installation of remote-handling typed EBSD-OIM analyzer for heavy irradiated reactor materials

    International Nuclear Information System (INIS)

    Kato, Yoshiaki; Takada, Fumiki; Ohmi, Masao; Nakagawa, Tetsuya; Miwa, Yukio

    2008-06-01

    The remote-handling typed EBSD-OIM analyzer for heavy irradiated reactor materials was installed in the JMTR hot laboratory at the first time in the world. The analyzer is used to study on IASCC (irradiation assisted stress corrosion cracking) or IGSCC (inter granular stress corrosion cracking) in reactor materials. This report describes the measurement procedure, the measured results and the operating experiences on the analyzer in the JMTR hot laboratory. (author)

  17. Electrical characterization of 10B doped diamond irradiated with low thermal neutron fluence

    International Nuclear Information System (INIS)

    Reed, M.L.; Reed, M.J.; Jagannadham, K.; Verghese, K.; Bedair, S.M.; El-Masry, N.; Butler, J.E.

    2004-01-01

    A sample of 10 B isotope doped diamond was neutron irradiated to a thermal fluence of 1.3x10 19 neutron cm -2 . The diamond sample was cooled continuously during irradiation in a nuclear reactor. 7 Li is formed by nuclear transmutation reaction from 10 B. Characterization for electrical conductance in the temperature range of 160 K 10 B doped sample and the 10 B doped and irradiated sample. The unirradiated diamond sample showed p-type conductance at higher temperature (T>200 K) and p-type surface conductance at lower temperature (T 7 Li that is formed by nuclear transmutation reaction from 10 B atoms. Also, compensation of n-type carriers from 7 Li by p-type carriers from 10 B is used to interpret the conductance above 400 K. A low concentration of radiation induced defects, absence of defect complexes, and the low activation energy of n-type 7 Li are thought responsible for the observed variation of conductance in the irradiated diamond. The present results illustrate that neutron transmutation from 10 B doped diamond is a useful method to achieve n-type conductivity in diamond

  18. Cytosine modifications after gamma irradiation in aerated aqueous solution of Escherichia coli DNA

    International Nuclear Information System (INIS)

    Polverelli, M.

    1983-04-01

    After gamma irradiation of cytosine in aerated aqueous solution and utilization of various spectrometric methods (mass spectrometry, proton nuclear magnetic resonance and infrared spectrometry) about ten new radiolysis products were identified. The formation of N-glycolylbiuret in H 2 18 O aqueous solution of irradiated cytosine at pH 4,5 indicated that the preferred 18 OH hydroxyl radical attack was at C-5. The formation of trans 1-carbamoyl-4,5 dihydroxyimidazolidin-2 oxo which is the major product after cytosine pyrimidine ring rearrangement took place preferentially at neutral pH, while N-glycolylbiuret predominated at pH 4,5. The deamination pathway was predominant when cytosine was irradiated at acidic pH values (pH 2 ) or in copper complexes. The development of a new acid hydrolysis method using fluorhydric acid stabilized in pyridine made easier the evaluation of cytosine modifications after gamma irradiation in aerated aqueous solution of E. Coli DNA- 14 C-2 cytosine. This hydrolytic agent removed the modified bases from the polynucleotidic chain. A difference was found between the proportion of radiolytic products removed by acid hydrolysis and by irradiation of the free base in solution [fr

  19. Expression of p53, MDM2 in a mice hydradecarcinoma model induced by γ-ray irradiation

    International Nuclear Information System (INIS)

    Huang Yuecheng; Cai Jianming; Han Ling; Gao Fu; Sun Ding; Dong Zhitao; Zhe Wanli

    2004-01-01

    Objective: To investigate the role of the p53, MDM2 in carcinogenesis of mice hydradecarcinoma induced by γ-rays. Methods: A radiation-induced mice hydradecarcinoma model was established by γ-ray irradiation. Expression of MDM2 protein in hydradecarcinoma tissue, paracancerous tissue and normal control tissue was detected with Western blot. Immunoprecipitation (IP) was conducted to examine the phosphorylation level of MDM2 protein. PCR-SSCP was performed to detect p53 gene mutation. Results: Compared with the normal control tissue, the MDM2 protein expression and its phosphorylation level were significantly higher in hydradecarcinoma tissue. SSCP showed there were p53 gene mutations in hydradecarcinoma samples. Conclusion: p53/MDM2 pathway may be involved in the development and progression of hydradecarcinoma induced by γ-ray irradiation. The over-expression of MDM2 and hyperphosphorylation may be responsible for malignant transformation induced by irradiation by a possible mechanism of p53 inactivation. The gene mutation of p53 further supported the hypothesis that p53/MDM2 pathway played a central role in carcinogenesis of γray induced hydradecarcinoma. (authors)

  20. Electrical and optical properties of neutron-irradiated GaP crystals

    International Nuclear Information System (INIS)

    Kawakubo, T.; Okada, M.

    1990-01-01

    Infrared absorption, electron paramagnetic resonance (EPR) spectra, and the electrical resistivity of semi-insulating liquid encapsulated Czochralski GaP crystals irradiated by fast neutrons with a dose of 7.6x10 18 n cm -2 have been studied. The electrical resistivity decreases with irradiation from 10 6 Ω cm to 1.5 kΩ cm. The temperature dependence of resistivity at low temperature is fitted to exp(b/T 1/4 ). The strong continuous optical absorption extends to 0.32 eV and its tail spreads until 0.12 eV. The EPR spectrum exhibits a broad singlet at 77 K and a doublet with five line structures at room temperature, which is attributed to antisite defects P Ga . The strong infrared absorption begins to be annealed at 150 degree C, and the EPR broad singlet decreases with anneals in the same temperature range. The strong infrared absorption is assumed to arise from interstitial phosphorus clusters. A discussion is given concerning the species responsible for the EPR singlet

  1. N-type doping of InGaN by high energy particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yu, K.M. [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley CA, 94720 (United States)

    2009-06-15

    This article reviews our extensive studies of the effects of native defects introduced by high energy particles on the electrical and optical properties of InGaN alloys. We show that the electronic properties of irradiated InGaN can be well described by the amphoteric defect model. Because of the extremely low position of the conduction band edge of InN the formation energy of native donor defects is very low in In-rich InGaN alloys. High energy particle irradiation of InN and In-rich InGaN, will therefore produce donor defects and result in more n-type materials. As the irradiation dose increases, the electron concentration increases until the Fermi energy E{sub F} approaches the Fermi stabilization energy E{sub FS}. At this point both donor and acceptor-type defects are formed at similar rates, and compensate each other, leading to stabilization of E{sub F} and a saturation of the electron concentration. Hence a large increase and then saturation in the Burstein-Moss shift of the optical absorption edge is also observed. Furthermore we also found that mobilities in the irradiated films can be well described by scattering from triply charged defects, providing strong evidence that native defects in InN are triple donors. The excellent agreement between the experimental results and predictions based on the ADM suggests that particle irradiation can be an effective and simple method to control the doping (electron concentration) in In-rich In{sub x}Ga{sub 1-x}N via native point defects. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. N-type doping of InGaN by high energy particle irradiation

    International Nuclear Information System (INIS)

    Yu, K.M.

    2009-01-01

    This article reviews our extensive studies of the effects of native defects introduced by high energy particles on the electrical and optical properties of InGaN alloys. We show that the electronic properties of irradiated InGaN can be well described by the amphoteric defect model. Because of the extremely low position of the conduction band edge of InN the formation energy of native donor defects is very low in In-rich InGaN alloys. High energy particle irradiation of InN and In-rich InGaN, will therefore produce donor defects and result in more n-type materials. As the irradiation dose increases, the electron concentration increases until the Fermi energy E F approaches the Fermi stabilization energy E FS . At this point both donor and acceptor-type defects are formed at similar rates, and compensate each other, leading to stabilization of E F and a saturation of the electron concentration. Hence a large increase and then saturation in the Burstein-Moss shift of the optical absorption edge is also observed. Furthermore we also found that mobilities in the irradiated films can be well described by scattering from triply charged defects, providing strong evidence that native defects in InN are triple donors. The excellent agreement between the experimental results and predictions based on the ADM suggests that particle irradiation can be an effective and simple method to control the doping (electron concentration) in In-rich In x Ga 1-x N via native point defects. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. Magnetic Carbon Nanotubes as a Theranostic Platform for Drug Delivery and Magnetic Resonance Imaging

    KAUST Repository

    Alkattan, Nedah

    2014-06-01

    Carbon nanotubes (CNTs) have special characteristics that made them good agents especially for biomedical applications. In this study, Fe3O4 nanoparticles were incorporated onto the surface of CNTs followed by polyethylene glycol (PEG) grafting forming CNTs-Fe3O4-PEG hybrids. The PEGylation improves their biocompatibility, water solubility, and increases blood circulation. CNTs-Fe3O4-PEG was used as T2-contrat agent for magnetic resonance imaging (MRI). In addition, doxorubicin (DOX) was loaded onto CNTs-Fe3O4-PEG. The release of DOX from DOX-loaded CNTs-Fe3O4-PEG was tested under different pH conditions (7.4, 6.3 and 5.2). The release increased at acidic pH compared to neutral pH, which shows the sensitivity of the system to pH change. Triggering the release by Near Infra-Red (NIR) irradiation was furthermore investigated. The release increased after irradiation with NIR compared to control sample. These result prove that the designed system can be triggered by an internal stimuli (pH) and external stimuli (NIR irradiation) making it a promising candidate to be used for biomedical applications.

  4. Magnetohydrodynamic study for three-dimensional instability of the Petschek type magnetic reconnection

    International Nuclear Information System (INIS)

    Shimizu, T.; Kondoh, K.

    2013-01-01

    The 3D instability of the spontaneous fast magnetic reconnection process is studied with magnetohydrodynamics (MHD) simulations, where the 2D model of the spontaneous fast magnetic reconnection is destabilized in three dimension. As well known in many 2D numerical MHD studies, when a 1D current sheet is destabilized with the current-driven anomalous resistivity, the 2D Petschek type fast magnetic reconnection is established. This paper shows that the 2D Petschek type fast magnetic reconnection can be destabilized in three dimension by an initial resistive disturbance which includes a weak fluctuation in the sheet current direction, i.e., along the magnetic neutral line. The resulting 3D fast magnetic reconnection finally becomes intermittent and random through a 3D instability. In addition, it is also shown that the 3D instability is suppressed by the uniform resistivity. It suggests that the 3D instability is caused in the Petschek-type reconnection process which is characterized by a strongly localized magnetic diffusion region and the slow shock acceleration of the plasma jets and is suppressed in the Sweet-Parker type reconnection process

  5. Effect of fast-neutron irradiation on plastic deformation of Type 304 stainless steel

    International Nuclear Information System (INIS)

    Yamada, H.

    1978-01-01

    Plastic deformation of EBR-II-irradiated Type 304 stainless steel was investigated by a stress-relaxation method. The stress-strain-rate relationships for the irradiated specimens at room temperature are concave upward, which are similar to those for the unirradiated specimens. However, concave downward behavior in the stress-strain-rate relationships were observed at much lower temperatures for the irradiated specimens in contrast to the unirradiated specimens. These results were analyzed succccessfully using Hart's mechanical equation-of-state concept. It was found that the hardness sigma*, which is the minimum stress necessary for the dislocation to overcome obstacles without thermal activation, increases linearly with fast-neutron fluence. This increase in sigma* is consistent with so-called ''irradiation hardening.'' In addition, resistance to dislocation glide, which is quantitatively measured in terms of sigma 0 , was observed to decrease linearly with fast-neutron fluence. The decrease in sigma 0 can be attributed to a decrease of solute drag due to irradiation-induced solute segregation

  6. Study by AES, EELS Spectroscopy of electron Irradiation on InP and InPO4/InP in comparison with Monte Carlo simulation

    International Nuclear Information System (INIS)

    Lounis, Z; Bouslama, M; Hamaida, K; Abdellaoui, A; Ouerdane, A; Ghaffour, M; Berrouachedi, N; Jardin, C

    2012-01-01

    We give the great interest to characterise the InP and InPO 4 /InP submitted to electron beam irradiation owing to the Auger Electron Spectroscopy (AES) associated to both methods Electron Energy Loss Spectroscopy (EELS). The incident electron produces breaking of (In-P) chemical bonds. The electron beam even acts to stimulate oxidation of InP surface involving on the top layers. Other, the oxide InPO 4 developed on InP does appear very sensitive to the irradiation due to electron beam shown by the monitoring of EELS spectra recorded versus the irradiated times of the surface. There appears a new oxide thought to be In 2 O 3 . We give the simulation methods Casino (Carlo simulation of electron trajectory in solids) for determination with accuracy the loss energy of backscattered electrons and compared with reports results have been obtained with EELS Spectroscopy. These techniques of spectroscopy alone do not be able to verify the affected depth during interaction process. So, using this simulation method, we determine the interaction of electrons in the matter.

  7. TU-H-CAMPUS-TeP1-03: Magnetically Focused Proton Irradiation of Small Volume Radiosurgery Targets

    Energy Technology Data Exchange (ETDEWEB)

    McAuley, GA; Slater, JM [Loma Linda University, Loma Linda, CA (United States); Wroe, AJ [Loma Linda University, Loma Linda, CA (United States); Loma Linda University Medical Center, Loma Linda, CA (United States)

    2016-06-15

    Purpose: To investigate the use of magnetic focusing for small volume proton radiosurgery targets using a triplet combination of quadrupole rare earth permanent magnet Halbach cylinder assemblies Methods: Fourteen quadrupole magnets consisting of 24 segments of radiation hard samarium-cobalt adhered into k=3 Halbach cylinders with various field gradients (100 to 250 T/m) were designed and manufactured. Triplet combinations of the magnets were placed on a positioning track on our Gantry 1 treatment table. Unmodulated 127 MeV proton beams with initial diameters of 3 to 20 mm were delivered to a water tank using single-stage scattering. Depth and transverse dose distributions were measured using a PTW PR60020 diode detector and EBT3 film, respectively. This data was compared with unfocused passively collimated beams. Monte Carlo simulations were also performed - both for comparison with experimental data and to further investigate the potential of triplet magnetic focusing. Results: Experimental results using 150 T/m gradient magnets and 15 to 20 mm initial diameter beams show peak to entrance dose ratios that are ∼ 43 to 48 % larger compared with spot size matched 8 mm collimated beams (ie, transverse profile full-widths at 90% maximum dose match within 0.5 mm of focused beams). In addition, the focusing beams were ∼ 3 to 4.4 times more efficient per MU in dose to target delivery. Additional results using different magnet combinations will also be presented. Conclusion: Our results suggest that triplet magnetic focusing could reduce entrance dose and beam number while delivering dose to small (∼≤ 10 mm diameter) radiosurgery targets in less time compared to unfocused beams. Immediate clinical applications include those associated with proton radiosurgery and functional radiosurgery of the brain and spine, however other treatment sites can be also envisioned. This project was sponsored with funding from the Department of Defense (DOD# W81XWH-BAA-10-1).

  8. Frequency-domain analysis of resonant-type ring magnet power supplies

    International Nuclear Information System (INIS)

    Kim, J.M.S.; Reiniger, K.W.

    1993-01-01

    For fast-cycling synchrotrons, resonant-type ring magnet power supplies are commonly used to provide a dc-biased ac excitation for the ring magnets. Up to the present, this power supply system has been analyzed using simplified analytical approximation, namely assuming the resonant frequency of the ring magnet network is fixed and equal to the accelerator frequency. This paper presents a frequency-domain analysis technique for a more accurate analysis of resonant-type ring magnet power supplies. This approach identifies that, with the variation of the resonant frequency, the operating conditions of the power supply changes quite dramatically because of the high Q value of the resonant network. The analytical results are verified, using both experimental results and simulation results

  9. Irradiation effects in low T$_{c}$ superconductors

    CERN Document Server

    Flükiger, René

    2009-01-01

    The effects of neutron irradiation on the superconducting parameters Tc, Bc2 and Jc of Nb3Sn are reviewed in view of the determination of the radiation limit in the LHC upgrade magnets. The variation of Jc in binary as well as in Ti and Ta alloyed Nb3Sn wires is presented. The coexisting defect mechanisms in irradiated Nb3Sn type compounds are briefly presented and a model is discussed explaining the site exchange mechanism which leads to a decrease of atomic ordering after irradiation. Based on calculations of F. Cerutti and coworkers (CERN), the neutron fluence at the inner winding of the quadrupole Q2a is estimated to values below 1018 neutrons /cm2 for a life time of 10 years, which is within the safety margin with respect to the critical current density and Bc2.

  10. Preparation and magnetic characterization of Y-type hexaferrites containing zinc, cobalt and copper

    International Nuclear Information System (INIS)

    Bai Yang; Zhou Ji; Gui Zhilun; Yue Zhensing; Li Longtu

    2003-01-01

    Y-type hexaferrites series with Ba 2 Me 2 Fe 12 O 22 (Me=Zn, Co, Cu) has been prepared by the solid-state reaction method. Y-type polycrystalline hexaferrite powders were characterized by X-ray diffraction and the magnetic characteristics were investigated by vibrating samples magnetometer. Experimental results show that the substitution of Co for Zn leads to a decrease of saturation magnetization and an increase of magnetic anisotropy. At room temperature, saturation magnetization does not increase linearly as Zn content increases due to the effect of the thermal agitation. Saturation magnetization of the Zn-Cu Y-type ferrite exhibits the similar variational rule at room temperature. As Cu substitute for Co, the saturation magnetization and magnetic anisotropy all decrease. Cu modification can lower the single-phase formed temperature distinctly as the magnetic properties slightly debase

  11. Antiviral T cell competence and restriction specificity of mixed allogeneic (P1 + P2----P1) irradiation chimeras

    International Nuclear Information System (INIS)

    Rueedi, E.S.; Sykes, M.; Ildstad, S.T.; Chester, C.H.; Althage, A.; Hengartner, H.; Sachs, D.H.; Zinkernagel, R.M.

    1989-01-01

    Mixed irradiation bone marrow chimeras were prepared by reconstituting lethally irradiated C57BL/10 (B10) or B10.D2 mice with T cell-depleted bone marrow cells of B10 plus B10.D2 origin. These chimeras were healthy and survived well under conventional housing conditions and after experimental laboratory infections. Of a total of 17 chimeras tested, 2 died spontaneously or from the injected virus. Twelve of fifteen chimeras mounted a measurable cytotoxic T cell response to virus. Despite approximately equal percentages of B10 and B10.D2 lymphocytes in chimeras, cytotoxic T cell responses to vaccinia virus and lymphocytic choriomeningitis virus were mediated variably by either syngeneic or allogeneic donor lymphocytes; thus the H-2 type of effector T cells frequently did not correspond to the 50:50 distribution of spleen or peripheral blood lymphocytes. Cytotoxic responses were restricted exclusively to recipient H-2 type. All mixed chimeras examined were able to mount a good IgG response to vesicular stomatitis virus. These results confirm previous data suggesting that such mixed chimeras are healthy and immunocompetent and demonstrate strict recipient-determined restriction specificity of effector T cells; they also suggest that if T help is necessary for induction of virus-specific cytotoxic T cells, it does not require host-restricted interactions between helper T cells and precursor cytotoxic T cells

  12. Analysis of Low Dose Irradiation Damages in Structural Ferritic/Martensitic Steels by Proton Irradiation and Nanoindentation

    International Nuclear Information System (INIS)

    Waseem, Owais A.; Ryu, Ho Jin; Park, Byong Guk; Jeong, Jong Ryul; Maeng, Cheol Soo; Lee, Myoung Goo

    2016-01-01

    As a result, ferritic-martensitic steels find applications in the in-core and out-of-core components which include ducts, piping, pressure vessel and cladding, etc. Due to ferromagnetism of F/M steel, it has been successfully employed in solenoid type fuel injector. Although the irradiation induced degradation in ferritic martensitic steels is lower as compare to (i) reduced activation steels, (ii) austenitic steels and (iii) martensitic steels, F/M steels are still prone to irradiation induced hardening and void swelling. The irradiation behavior may become more sophisticated due to transmutation and production of helium and hydrogen. The ductile to brittle transition temperature of F/M steels is also expected to increase due to irradiation. These irradiation induced degradations may deteriorate the integrity of F/M components. As a result of these investigations, it has found that the F/M steels experience no irradiation hardening above 400 .deg. C, but below this temperature, up to 350 .deg. C, weak hardening is observed. The irradiation hardening becomes more pronounced below 300 .deg. C. Moreover, the irradiation hardening has also found dependent upon radiation damage. The hardening was found increasing with increasing dose. Due to pronounced irradiation hardening below 300 .deg. C and increasing radiation damage with increasing dose (even at low dpa), it is required to investigate the post irradiation mechanical properties of F/M steel, in order to confirm its usefulness in structural and magnetic components which experience lifetime doses as low as 1x10"-"5 dpa.

  13. Analysis of Low Dose Irradiation Damages in Structural Ferritic/Martensitic Steels by Proton Irradiation and Nanoindentation

    Energy Technology Data Exchange (ETDEWEB)

    Waseem, Owais A.; Ryu, Ho Jin; Park, Byong Guk [KAIST, Daejeon (Korea, Republic of); Jeong, Jong Ryul [Chungnam University, Daejeon (Korea, Republic of); Maeng, Cheol Soo; Lee, Myoung Goo [KEPCO, Daejeon (Korea, Republic of)

    2016-05-15

    As a result, ferritic-martensitic steels find applications in the in-core and out-of-core components which include ducts, piping, pressure vessel and cladding, etc. Due to ferromagnetism of F/M steel, it has been successfully employed in solenoid type fuel injector. Although the irradiation induced degradation in ferritic martensitic steels is lower as compare to (i) reduced activation steels, (ii) austenitic steels and (iii) martensitic steels, F/M steels are still prone to irradiation induced hardening and void swelling. The irradiation behavior may become more sophisticated due to transmutation and production of helium and hydrogen. The ductile to brittle transition temperature of F/M steels is also expected to increase due to irradiation. These irradiation induced degradations may deteriorate the integrity of F/M components. As a result of these investigations, it has found that the F/M steels experience no irradiation hardening above 400 .deg. C, but below this temperature, up to 350 .deg. C, weak hardening is observed. The irradiation hardening becomes more pronounced below 300 .deg. C. Moreover, the irradiation hardening has also found dependent upon radiation damage. The hardening was found increasing with increasing dose. Due to pronounced irradiation hardening below 300 .deg. C and increasing radiation damage with increasing dose (even at low dpa), it is required to investigate the post irradiation mechanical properties of F/M steel, in order to confirm its usefulness in structural and magnetic components which experience lifetime doses as low as 1x10{sup -5} dpa.

  14. Estimations on uranium silicide fuel prototypes for their irradiation and postirradiation

    International Nuclear Information System (INIS)

    Sbaffoni, Maria M.

    2000-01-01

    The 'Silicide' project includes the qualification of this type of research reactor fuel to be used i.e. in the Argentine RA-3 and to confirm CNEA's role as an international supplier. The present paper shows complementary basic information for P-04 prototype post-irradiation, which is already under way, and some parameter values related to the new P-06 prototype to be taken into account for planning its irradiation and post-irradiation. The reliability of these values has been evaluated through comparison with experimental results. The reported results contribute, also, to a parallel study on the nuclear data libraries used in calculations for this type of reactor. (author)

  15. Analytical model and design of spoke-type permanent-magnet machines accounting for saturation and nonlinearity of magnetic bridges

    Science.gov (United States)

    Liang, Peixin; Chai, Feng; Bi, Yunlong; Pei, Yulong; Cheng, Shukang

    2016-11-01

    Based on subdomain model, this paper presents an analytical method for predicting the no-load magnetic field distribution, back-EMF and torque in general spoke-type motors with magnetic bridges. Taking into account the saturation and nonlinearity of magnetic material, the magnetic bridges are equivalent to fan-shaped saturation regions. For getting standard boundary conditions, a lumped parameter magnetic circuit model and iterative method are employed to calculate the permeability. The final field domain is divided into five types of simple subdomains. Based on the method of separation of variables, the analytical expression of each subdomain is derived. The analytical results of the magnetic field distribution, Back-EMF and torque are verified by finite element method, which confirms the validity of the proposed model for facilitating the motor design and optimization.

  16. Pallet irradiators: circumstances under which this type of system is appropriate

    International Nuclear Information System (INIS)

    McKinnon, R.G.; Beers, E.W.

    1993-01-01

    Several pallet irradiator systems have been designed and installed in the past few years. These systems are of considerably different design and application. Systems which use full size pallets have been designed for both food and medical disposables. Designs utilizing Europallets have also been installed for specific applications. The basic advantage of these systems is the ability to handle the product in its final shipping configuration, therefore, reducing labour and cost to process. This, weighed against the radiation performance of this type of facility, has in several instances shown advantages over other designs. Several designs will be discussed to describe advantages of using pallet irradiator designs. (author)

  17. Developments in the processing and properties of NdFeb-type permanent magnets

    International Nuclear Information System (INIS)

    Brown, David; Ma, B.-M.; Chen Zhongmin

    2002-01-01

    The composition, microstructure and processing of NdFeB-type permanent magnets are all critical factors for the successful production of high performance magnet components. Three common fabrication routes can be used to categorize these NdFeB-based bulk magnets: sintering, polymer bonding and hot deformation. Generally, the former type of magnet has a high-energy product (30-50 MGOe), full density and a relatively simple shape. Bonded magnets have intermediate energy products (10-18 MGOe), lower density and can be formed into intricate net-shapes. Hot deformed magnets possess full density, intermediate to high-energy products (15-46 MGOe), isotropic or anisotropic properties and have the potential to be formed into net shapes. This article discusses the critical issues of improved magnetic performance, environmental stability, net-shape formability and magnetization behavior for the main categories of NdFeB magnets

  18. The influence of P solutes on an irradiated α-Fe matrix

    International Nuclear Information System (INIS)

    Hurchand, H.; Kenny, S.D.; Sanz-Navarro, C.F.; Smith, R.; Flewitt, P.E.J.

    2005-01-01

    Atomistic simulations of collision cascades in a Fe-0.04at.%P matrix and a pure Fe matrix are compared to investigate the interaction of the phosphorus atoms with the radiation. The simulations were performed for a primary knock-on atom having an energy in the range 1-16 keV. It is observed that the P atom in the Fe matrix does not increase significantly the damage induced to the lattice post irradiation. The density of vacancies and the morphology of the clusters formed in the Fe-0.04at.%P system are indistinguishable from residual defects produced in a pure irradiated Fe matrix. There are two mechanisms by which the Fe interstitials interact with the P atoms. The first occurs when a P atom is dislodged from its substitutional position by a recoil atom and combines with an Fe interstitial to form a mixed dumbbell. The second is one in which the Fe interstitial is attracted to a substitutional P atom due to the lattice strain region in the vicinity of the P atom. In this case the P atom acts as an attractive centre for interstitial Fe atoms and stabilises them into Fe-P nano-clusters. Nearly 35% of the atoms which are ejected from the core region of the cascade during the ballistic phase form such solute-defect clusters which remain pinned over the period of several hundred picoseconds. Finally, the radiation induced mobility of the P atom is reported. Substitutional P atoms whether isolated or as part of the larger defect clusters have a high energy barrier for diffusion but the P atoms displaced from substitutional sites can diffuse through the lattice by hopping between dumbbell and tetrahedral sites

  19. A novel p53 mutational hotspot in skin tumors from UV-irradiated Xpc mutant mice alters transactivation functions.

    Science.gov (United States)

    Inga, Alberto; Nahari, Dorit; Velasco-Miguel, Susana; Friedberg, Errol C; Resnick, Michael A

    2002-08-22

    A mutation in codon 122 of the mouse p53 gene resulting in a T to L amino acid substitution (T122-->L) is frequently associated with skin cancer in UV-irradiated mice that are both homozygous mutant for the nucleotide excision repair (NER) gene Xpc (Xpc(-/-)) and hemizygous mutant for the p53 gene. We investigated the functional consequences of the mouse T122-->L mutation when expressed either in mammalian cells or in the yeast Saccharomyces cerevisiae. Similar to a non-functional allele, high expression of the T122-->L allele in p53(-/-) mouse embryo fibroblasts and human Saos-2 cells failed to suppress growth. However, the T122-->L mutant p53 showed wild-type transactivation levels with Bax and MDM2 promoters when expressed in either cell type and retained transactivation of the p21 and the c-Fos promoters in one cell line. Using a recently developed rheostatable p53 induction system in yeast we assessed the T122-->L transactivation capacity at low levels of protein expression using 12 different p53 response elements (REs). Compared to wild-type p53 the T122-->L protein manifested an unusual transactivation pattern comprising reduced and enhanced activity with specific REs. The high incidence of the T122-->L mutant allele in the Xpc(-/-) background suggests that both genetic and epigenetic conditions may facilitate the emergence of particular functional p53 mutations. Furthermore, the approach that we have taken also provides for the dissection of functions that may be retained in many p53 tumor alleles.

  20. Formation of 32P-labelled Polyphosphates in Reactor-irradiated Solutions of Orthophosphate

    DEFF Research Database (Denmark)

    Fenger, Jørgen Folkvard; Pagsberg, Palle Bjørn

    1973-01-01

    yield increases with the concentration of the irradiated solution and varies in a complicated way with the pH. These observations and some experiments with addition of radical scavengers indicate that oxidation of the 32P-recoils by OH-radicals is an important step in the polymerization. It is suggested...... that the actual formation of a P&z.sbnd;O&z.sbnd;P bridge takes place as an addition of a Lewis acid to a lone pair of electrons on a phosphate ion....

  1. Sensitivity of P-Channel MOSFET to X- and Gamma-Ray Irradiation

    Directory of Open Access Journals (Sweden)

    Milić Pejović

    2013-01-01

    Full Text Available Investigation of Al-gate p-channel MOSFETs sensitivity following irradiation using 200 and 280 kV X-ray beams as well as gamma-ray irradiation of 60Co in the dose range from 1 to 5 Gy was performed in this paper. The response followed on the basis of threshold voltage shift and was studied as a function of absorbed dose. It was shown that the most significant change in threshold voltage was in the case of MOSFET irradiation in X-ray fields of 200 kV and when the gate voltage was +5 V. For practical applications in dosimetry, the sensitivity of the investigated MOSFETs was also satisfactory for X-ray tube voltage of 280 kV and for gamma rays. Possible processes in gate oxide caused by radiation and its impact on the response of MOSFETs were also analyzed in this paper.

  2. Irradiation tests on PHWR type fuel elements in TRIGA research reactor of INR Pitesti

    Energy Technology Data Exchange (ETDEWEB)

    Horhoianu, Grigore [Institute for Nuclear Research, Pitesti (Romania). Nuclear Fuel Engineering Lab.; Sorescu, Ion [Institute for Nuclear Research, Pitesti (Romania). TRIGA Reactor Loop Facility; Parvan, Marcel [Institute for Nuclear Research, Pitesti (Romania). Hot Cells Lab.

    2012-12-15

    Nine PHWR type fuel elements with reduced length were irradiated in loop A of the TRIGA Research Reactor of INR Pitesti. The primary objective of the test was to determine the performance of nuclear fuel fabricated at INR Pitesti at high linear powers in pressurized water conditions. Six fuel elements were irradiated with a ramp power history, achieving a maximum power of 45 kW/m during pre-ramp and of 64 kW/m in the ramp. The maximum discharge burnup was of 216 MWh/kgU. Another three fuel elements with reduced length were irradiated with declining power history. At the beginning of irradiation the fuel elements achieved a maximum linear power of 66 kW/m. The maximum fuel power was about 1.3 times the maximum expected in PHWR. The maximum discharge burnup was 205 MWh/kgU. The elements were destructively examined in the hot cells of INR Pitesti. Temperature-sensitive parameters such as UO{sub 2} grain growth, fission-gas release and sheath deformations were examined. The tests proved the feasibility of irradiating PHWR type fuel elements at linear powers up to 66 kW/m under pressurized water conditions and demonstrated the possibility of more flexible operation of this fuel in power reactors. This paper presents the results of the investigation. (orig.)

  3. Solar surface magnetism and irradiance on time scales

    NARCIS (Netherlands)

    Domingo, V.; Ermolli, I.; Fox, P.; Fröhlich, C.; Haberreiter, M.; Krivova, N.; Kopp, G.; Schmutz, W.; Solanki, S.K.; Spruit, H.C.; Unruh, Y.C.; Vögler, A.

    2009-01-01

    The uninterrupted measurement of the total solar irradiance during the last three solar cycles and an increasing amount of solar spectral irradiance measurements as well as solar imaging observations (magnetograms and photometric data) have stimulated the development of models attributing irradiance

  4. EUV and Magnetic Activities Associated with Type-I Solar Radio Bursts

    Science.gov (United States)

    Li, C. Y.; Chen, Y.; Wang, B.; Ruan, G. P.; Feng, S. W.; Du, G. H.; Kong, X. L.

    2017-06-01

    Type-I bursts ( i.e. noise storms) are the earliest-known type of solar radio emission at the meter wavelength. They are believed to be excited by non-thermal energetic electrons accelerated in the corona. The underlying dynamic process and exact emission mechanism still remain unresolved. Here, with a combined analysis of extreme ultraviolet (EUV), radio and photospheric magnetic field data of unprecedented quality recorded during a type-I storm on 30 July 2011, we identify a good correlation between the radio bursts and the co-spatial EUV and magnetic activities. The EUV activities manifest themselves as three major brightening stripes above a region adjacent to a compact sunspot, while the magnetic field there presents multiple moving magnetic features (MMFs) with persistent coalescence or cancelation and a morphologically similar three-part distribution. We find that the type-I intensities are correlated with those of the EUV emissions at various wavelengths with a correlation coefficient of 0.7 - 0.8. In addition, in the region between the brightening EUV stripes and the radio sources there appear consistent dynamic motions with a series of bi-directional flows, suggesting ongoing small-scale reconnection there. Mainly based on the induced connection between the magnetic motion at the photosphere and the EUV and radio activities in the corona, we suggest that the observed type-I noise storms and the EUV brightening activities are the consequence of small-scale magnetic reconnection driven by MMFs. This is in support of the original proposal made by Bentley et al. ( Solar Phys. 193, 227, 2000).

  5. Production and aging of paramagnetic point defects in P-doped floating zone silicon irradiated with high fluence 27 MeV electrons

    Science.gov (United States)

    Joita, A. C.; Nistor, S. V.

    2018-04-01

    Enhancing the long term stable performance of silicon detectors used for monitoring the position and flux of the particle beams in high energy physics experiments requires a better knowledge of the nature, stability, and transformation properties of the radiation defects created over the operation time. We report the results of an electron spin resonance investigation in the nature, transformation, and long term stability of the irradiation paramagnetic point defects (IPPDs) produced by high fluence (2 × 1016 cm-2), high energy (27 MeV) electrons in n-type, P-doped standard floating zone silicon. We found out that both freshly irradiated and aged (i.e., stored after irradiation for 3.5 years at 250 K) samples mainly contain negatively charged tetravacancy and pentavacancy defects in the first case and tetravacancy defects in the second one. The fact that such small cluster vacancy defects have not been observed by irradiation with low energy (below 5 MeV) electrons, but were abundantly produced by irradiation with neutrons, strongly suggests the presence of the same mechanism of direct formation of small vacancy clusters by irradiation with neutrons and high energy, high fluence electrons, in agreement with theoretical predictions. Differences in the nature and annealing properties of the IPPDs observed between the 27 MeV electrons freshly irradiated, and irradiated and aged samples were attributed to the presence of a high concentration of divacancies in the freshly irradiated samples, defects which transform during storage at 250 K through diffusion and recombination processes.

  6. A low dose pre-irradiation induces radio- and heat-resistance via HDM2 and NO radicals, and is associated with p53 functioning

    Science.gov (United States)

    Takahashi, A.; Ohnishi, T.

    2009-04-01

    The aim of this work was to clarify the effect of low dose pre-irradiation on radio- and heat-sensitivity. Wild-type (wt) p53 and mutated (m) p53 cells derived from the human lung cancer H1299 cell line were used. The parental H1299 cell line is p53-null. Cellular sensitivities were determined with a colony-forming assay. When wtp53 cells were exposed to a low dose X-irradiation, induction of radio- and heat-resistance was observed only in the absence of RITA (an inhibitor of p53-HDM2 interactions), aminoguanidine (an iNOS inhibitor) and c-PTIO (an NO radical scavenger). In contrast, the induced radio- and heat-resistance was not observed under similar conditions in mp53 cells. Moreover, heat-resistance as well as radio-resistance developed when wtp53 cells were treated with ISDN (an NO generating agent) alone. These findings suggest that NO radicals are an initiator of radio- and heat-resistance, and function through the activation of HDM2 and the depression of p53 accumulation.

  7. Tensile stress corrosion cracking of type 304 stainless steel irradiated to very high dose

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H. M.; Ruther, W. E.; Strain, R. V.; Shack, W. J.

    2001-09-01

    Certain safety-related core internal structural components of light water reactors, usually fabricated from Type 304 or 316 austenitic stainless steels (SSs), accumulate very high levels of irradiation damage (20--100 displacement per atom or dpa) by the end of life. The data bases and mechanistic understanding of, the degradation of such highly irradiated components, however, are not well established. A key question is the nature of irradiation-assisted intergranular cracking at very high dose, i.e., is it purely mechanical failure or is it stress-commotion cracking? In this work, hot-cell tests and microstructural characterization were performed on Type 304 SS from the hexagonal fuel can of the decommissioned EBR-11 reactor after irradiation to {approximately}50 dpa at {approximately}370 C. Slow-strain-rate tensile tests were conducted at 289 C in air and in water at several levels of electrochemical potential (ECP), and microstructural characteristics were analyzed by scanning and transmission electron microcopies. The material deformed significantly by twinning and exhibited surprisingly high ductility in air, but was susceptible to severe intergranular stress corrosion cracking (IGSCC) at high ECP. Low levels of dissolved O and ECP were effective in suppressing the susceptibility of the heavily irradiated material to IGSCC, indicating that the stress corrosion process associated with irradiation-induced grain-boundary Cr depletion, rather than purely mechanical separation of grain boundaries, plays the dominant role. However, although IGSCC was suppressed, the material was susceptible to dislocation channeling at low ECP, and this susceptibility led to poor work-hardening capability and low ductility.

  8. Study of p53 protein expression levels from irradiated peripheral blood lymphocytes for biodosimetry

    International Nuclear Information System (INIS)

    Cavalcanti, M.B.; Fernandes, T.S.; Melo, J.A.; Neves, M.A.B.; Machado, C.G.F

    2005-01-01

    Biodosimetry can be defined as the investigation of radioinduced biological effects in order to correlate them with the absorbed dose. Scoring of unstable chromosomal aberrations and micronuclei, from in vitro irradiated peripheral blood lymphocytes, is commonly used for biodosimetry based on cytogenetic analysis. However, this method of analysis is time-consuming, which may represent a pitfall when fast investigation of a possible exposure to ionizing radiation (IR) is needed. The interaction of IR with the living cell can cause injuries in the DNA molecules. However, normal cells possess mechanisms of repair that are capable to correct those damages. During the repair process of the DNA various proteins are expressed. Among these proteins, p53 plays an important role. This protein is a transcription factor that helps in the maintenance of the genomic integrity. p53 protein is found into the cytoplasm in reduced concentrations and has a short average life. However, expression of p53 protein can be induced by DNA harmful radioinduced, which increases the concentration and the average life of this protein, making possible its detection. Thus, the correlation between the increasing of p53 expression and the irradiation may constitute a fast and reliable method of individual monitoring in cases of accidental or suspected exposures to IR. In this context, the objective of this research was to evaluate the p53 protein expression levels from lymphocytes of the human peripheral blood after in vitro irradiation. For this, samples of peripheral blood from healthy individuals were irradiated with known doses. Lymphocytes were separated on ficoll gradient by centrifugation and re-suspended at 1x 10 6 /mL in RPMI medium enriched with fetal calf serum. Hence, lymphocytes were incubated in 5% CO 2 at 37 deg C prior to the methodology of flow cytometry, using intranuclear antigens for the quantification of p53. In this report, the methodology performed and the results obtained

  9. Study of p53 protein expression levels from irradiated peripheral blood lymphocytes for biodosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Cavalcanti, M.B.; Fernandes, T.S. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear; Amaral, A. [Universite Paris XII (UPXII) (France); Melo, J.A. [Centro de Radioterapia de Pernambuco (CERAPE), PE (Brazil); Neves, M.A.B.; Machado, C.G.F, E-mail: maribrayner@yahoo.com.br [Fundacao de Hematologia e Hemoterapia de Pernambuco, PE (Brazil)

    2005-07-01

    Biodosimetry can be defined as the investigation of radioinduced biological effects in order to correlate them with the absorbed dose. Scoring of unstable chromosomal aberrations and micronuclei, from in vitro irradiated peripheral blood lymphocytes, is commonly used for biodosimetry based on cytogenetic analysis. However, this method of analysis is time-consuming, which may represent a pitfall when fast investigation of a possible exposure to ionizing radiation (IR) is needed. The interaction of IR with the living cell can cause injuries in the DNA molecules. However, normal cells possess mechanisms of repair that are capable to correct those damages. During the repair process of the DNA various proteins are expressed. Among these proteins, p53 plays an important role. This protein is a transcription factor that helps in the maintenance of the genomic integrity. p53 protein is found into the cytoplasm in reduced concentrations and has a short average life. However, expression of p53 protein can be induced by DNA harmful radioinduced, which increases the concentration and the average life of this protein, making possible its detection. Thus, the correlation between the increasing of p53 expression and the irradiation may constitute a fast and reliable method of individual monitoring in cases of accidental or suspected exposures to IR. In this context, the objective of this research was to evaluate the p53 protein expression levels from lymphocytes of the human peripheral blood after in vitro irradiation. For this, samples of peripheral blood from healthy individuals were irradiated with known doses. Lymphocytes were separated on ficoll gradient by centrifugation and re-suspended at 1x 10{sub 6}/mL in RPMI medium enriched with fetal calf serum. Hence, lymphocytes were incubated in 5% CO{sub 2} at 37 deg C prior to the methodology of flow cytometry, using intranuclear antigens for the quantification of p53. In this report, the methodology performed and the results

  10. Improvement of open-type magnetically shielded room composed of magnetic square cylinders by controlling flux path

    International Nuclear Information System (INIS)

    Hirosato, S.; Yamazaki, K.; Tsuruta, T.; Haraguchi, Y.; Kosaka, M.; Gao, Y.; Muramatsu, K.; Kobayashi, K.

    2011-01-01

    We have developed an open-type magnetically shielded room composed of magnetic square cylinders that has been used for an actual MRI in a hospital. To improve shielding performance, we propose here a method to control the path of the magnetic flux in the wall composed of the magnetic square cylinders by changing the magnetic permeability in each direction of the square cylinders spatially. First, we discuss a method to control the magnetic permeability in each direction of the square cylinders independently by inserting slits without changing the outside dimensions of the square cylinders, by using 3-D magnetic field analysis. Then, the effectiveness of the design of controlling the flux pass was shown by magnetic field analysis and experiments. (author)

  11. Relation of twist of magnetic force tube and flare magnetic field

    International Nuclear Information System (INIS)

    Tanaka, H.

    1978-01-01

    The configuration of magnetic field and its development in the regions of big flare were investigated to study the features of magnetic force tubes. The photographs of delta type solar spots taken at Mt. Wilson Observatory were selected. 94 percent of the delta type spots belong to the class B activity or more active class. The features of delta type spots are the reverse configuration and the shear motion. The reverse configuration is divided into the p/f configuration and the f/p configuration. The shear motion is divided into the normal motion, the reverse motion, and the indefinite motion. Vortex structures appeared around the solar spots of reverse configuration showing normal motion. The relation among the direction of twist, reverse configuration and the direction of shear motion was deduced. In the region of normal motion, the p/f configuration corresponds to the reverse S type vortices and the f/p configuration to S type. In the region of reverse motion, the p/f configuration corresponds to the S type vortices and the f/p corresponds to the reverse S type vortices. The mechanism of development of delta type solar spots is discussed. (Kato, T.)

  12. Irradiation tests of ITER candidate Hall sensors using two types of neutron spectra

    International Nuclear Information System (INIS)

    Duran, I.; Bolshakova, I.; Holyaka, R.; Viererbl, L.; Lahodova, Z.; Sentkerestiova, J.; Bem, P.

    2010-01-01

    We report on irradiation tests of InSb based Hall sensors at two irradiation facilities with two distinct types of neutron spectra. One was a fission reactor neutron spectrum with a significant presence of thermal neutrons, while another one was purely fast neutron field. Total neutron fluence of the order of 10 16 cm -2 was accumulated in both cases, leading to significant drop of Hall sensor sensitivity in case of fission reactor spectrum, while stable performance was observed at purely fast neutron spectrum. This finding suggests that performance of this particular type of Hall sensors is governed dominantly by transmutation. Additionally, it further stresses the need to test ITER candidate Hall sensors under neutron flux with ITER relevant spectrum.

  13. Correlations for damage in diffused-junction InP solar cells induced by electron and proton irradiation

    International Nuclear Information System (INIS)

    Yamaguchi, M.; Takamoto, T.; Taylor, S.J.; Walters, R.J.; Summers, G.P.; Flood, D.J.; Ohmori, M.

    1997-01-01

    The damage to diffused-junction n + -p InP solar cells induced by electron and proton irradiations over a wide range of energy from 0.5 to 3 MeV and 0.015 to 20 MeV, respectively, has been examined. The experimental electron and proton damage coefficients have been analyzed in terms of displacement damage dose, which is the product of the particle fluence and the calculated nonionizing energy loss [G. P. Summers, E. A. Burke, R. Shapiro, S. R. Messenger, and R. J. Walters, IEEE Trans. Nucl. Sci. 40, 1300 (1993).] Degradation of InP cells due to irradiation with electrons and protons with energies of more than 0.5 MeV show a single curve as a function of displacement damage dose. Based on the deep-level transient spectroscopy analysis, damage equivalence between electron and proton irradiation is discussed. InP solar cells are confirmed to be substantially more radiation resistant than Si and GaAs-on-Ge cells. copyright 1997 American Institute of Physics

  14. P-adic Schroedinger type equation

    International Nuclear Information System (INIS)

    Vladimirov, V.S.; Volovich, I.V.

    1988-12-01

    In p-adic quantum mechanics a Schroedinger type equation is considered. We discuss the appropriate notion of differential operators. A solution of the Schroedinger type equation is given. A new set of vacuum states for the p-adic quantum harmonic oscillator is presented. The correspondence principle with the standard quantum mechanics is discussed. (orig.)

  15. Chemical-free n-type and p-type multilayer-graphene transistors

    Energy Technology Data Exchange (ETDEWEB)

    Dissanayake, D. M. N. M., E-mail: nandithad@voxtel-inc.com [Voxtel Inc, Lockey Laboratories, University of Oregon, Eugene Oregon 97402 (United States); Eisaman, M. D. [Sustainable Energy Technologies Department, Brookhaven National Laboratory, Upton, New York 11973 (United States); Department of Electrical and Computer Engineering, Stony Brook University, Stony Brook, New York 11794 (United States); Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794 (United States)

    2016-08-01

    A single-step doping method to fabricate n- and p-type multilayer graphene (MG) top-gate field effect transistors (GFETs) is demonstrated. The transistors are fabricated on soda-lime glass substrates, with the n-type doping of MG caused by the sodium in the substrate without the addition of external chemicals. Placing a hydrogen silsesquioxane (HSQ) barrier layer between the MG and the substrate blocks the n-doping, resulting in p-type doping of the MG above regions patterned with HSQ. The HSQ is deposited in a single fabrication step using electron beam lithography, allowing the patterning of arbitrary sub-micron spatial patterns of n- and p-type doping. When a MG channel is deposited partially on the barrier and partially on the glass substrate, a p-type and n-type doping profile is created, which is used for fabricating complementary transistors pairs. Unlike chemically doped GFETs in which the external dopants are typically introduced from the top, these substrate doped GFETs allow for a top gate which gives a stronger electrostatic coupling to the channel, reducing the operating gate bias. Overall, this method enables scalable fabrication of n- and p-type complementary top-gated GFETs with high spatial resolution for graphene microelectronic applications.

  16. MicroRNA-17-5p post-transcriptionally regulates p21 expression in irradiated betel quid chewing-related oral squamous cell carcinoma cells

    International Nuclear Information System (INIS)

    Wu, S.Y.; HungKuang Univ., Taichung; Lin, K.C.; Chiou, J.F.; Taipei Medical Univ. Hospital, Taipei; Taipei Medical Univ. Hospital, Taipei; Taipei Medical Univ. Hospital, Taipei; Jeng, S.C.; Cheng, W.H.; Chang, C.I.; Lin, W.C.; Wu, L.L.; Lee, H.L.; Chen, R.J.

    2013-01-01

    Background and purpose: Betel nut chewing is associated with oral cavity cancer in Taiwan. OC3 is an oral carcinoma cell line that was established from cells collected from a long-term betel nut chewer who does not smoke. After we found that microRNA-17-5p (miR-17-5p) is induced in OC3 cells, we used this cell line to examine the biological role(s) of this microRNA in response to exposure to ionizing radiation. Materials and methods: A combined SYBR green-based real-time PCR and oligonucleotide ligation assay was used to examine the expression of the miR-17 polycistron in irradiated OC3 cells. The roles of miR-17-5p and p21 were evaluated with specific antisense oligonucleotides (ODN) that were designed and used to inhibit their expression. Expression of the p21 protein was evaluated by Western blotting. The clonogenic assay and annexin V staining were used to evaluate cell survival and apoptosis, respectively. Cells in which miR-17-5p was stably knocked down were used to create ectopic xenografts to evaluate in vivo the role of miR-17-5p. Results: A radiation dose of 5 Gy significantly increased miR-17-5p expression in irradiated OC3 cells. Inhibition of miR-17-5p expression enhanced the radiosensitivity of the OC3 cells. We found that miR-17-5p downregulates radiation-induced p21 expression in OC3 cells and, by using a tumor xenograft model, it was found that p21 plays a critical role in increasing the radiosensitivity of OC3 cells in vitro and in vivo. Conclusion: miR-17-5p is induced in irradiated OC3 cells and it downregulates p21 protein expression, contributing to the radioresistance of OC3 cells. (orig.)

  17. MicroRNA-17-5p post-transcriptionally regulates p21 expression in irradiated betel quid chewing-related oral squamous cell carcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Wu, S.Y. [Taipei Medical Univ., Wan Fang Hospital, Taipei (China). Dept. of Radiation-Oncology; HungKuang Univ., Taichung (China). Dept. of Biotechnology; Lin, K.C. [Taipei Medical Univ., Wan Fang Hospital, Taipei (China). Dept. of Oral and Maxillofacial Surgery; Chiou, J.F. [Taipei Medical Univ., Taipei (China). Dept. of Radiology; Taipei Medical Univ. Hospital, Taipei (China). Dept. of Radiation Oncology; Taipei Medical Univ. Hospital, Taipei (China). Dept. of Hospice and Palliative Center; Taipei Medical Univ. Hospital, Taipei (China). Cancer Center; Jeng, S.C. [Taipei Medical Univ. Hospital, Taipei (China). Dept. of Radiation Oncology; Cheng, W.H.; Chang, C.I. [Taipei Medical Univ., Wan Fang Hospital, Taipei (China). Dept. of Hemato-Ongology; Lin, W.C. [Taipei Medical Univ., Wan Fang Hospital, Taipei (China). Div. of Thoracic Surgery; Wu, L.L. [National Taiwan Univ. Hospital, Taipei (China). Dept. of Ophthalmology; Lee, H.L. [Taipei Medical Univ., Wan Fang Hospital, Taipei (China). Dept. of Radiation-Oncology; Chen, R.J. [National Taiwan Univ. Hospital and National Taiwan Univ., Taipei (China). Dept. of Obstetrics and Gynecology

    2013-08-15

    Background and purpose: Betel nut chewing is associated with oral cavity cancer in Taiwan. OC3 is an oral carcinoma cell line that was established from cells collected from a long-term betel nut chewer who does not smoke. After we found that microRNA-17-5p (miR-17-5p) is induced in OC3 cells, we used this cell line to examine the biological role(s) of this microRNA in response to exposure to ionizing radiation. Materials and methods: A combined SYBR green-based real-time PCR and oligonucleotide ligation assay was used to examine the expression of the miR-17 polycistron in irradiated OC3 cells. The roles of miR-17-5p and p21 were evaluated with specific antisense oligonucleotides (ODN) that were designed and used to inhibit their expression. Expression of the p21 protein was evaluated by Western blotting. The clonogenic assay and annexin V staining were used to evaluate cell survival and apoptosis, respectively. Cells in which miR-17-5p was stably knocked down were used to create ectopic xenografts to evaluate in vivo the role of miR-17-5p. Results: A radiation dose of 5 Gy significantly increased miR-17-5p expression in irradiated OC3 cells. Inhibition of miR-17-5p expression enhanced the radiosensitivity of the OC3 cells. We found that miR-17-5p downregulates radiation-induced p21 expression in OC3 cells and, by using a tumor xenograft model, it was found that p21 plays a critical role in increasing the radiosensitivity of OC3 cells in vitro and in vivo. Conclusion: miR-17-5p is induced in irradiated OC3 cells and it downregulates p21 protein expression, contributing to the radioresistance of OC3 cells. (orig.)

  18. Magnetic fields in starspots on late-type giants

    International Nuclear Information System (INIS)

    Jahn, K.

    1985-01-01

    Computations of models of magnetic starspots on cool active giants show that the value of the magnetic intensity in spots is generally of the order of one kilogauss, although in larger spots the field can be as weak as a few hundred gauss. It is also argued, that spots on giants qualitatively differ from those on late-type dwarfs, since they cannot be too large. The largest individual spots can cover at most about one percent of a stellar hemisphere. This is in a very good agreement with earlier suggestions based on observations of spotted giants. The assumption that spots are the regions of the strongest magnetic field allows to discuss recent attempts of detection of the magnetic field on late-type giants. Polarimetric measurements most probably cannot be successful, due to a small field strength and a complex topology of the field. It is shown that even if a whole surface was covered by spots with relatively strong field, the resulting not longitudinal field would be as weak as a few gauss. Also methods independent of polarimetric measurements, based on the analysis of Zeeman broadening, generally are not sensitive enough to detect the magnetic field on giants, even in spots. λ And is discussed as an example. The comparison of models of spots computed for that stars with photometric observations suggests, that a dark region on λ And consists of hundreds of small spots (each of them smaller than about 0.1% of the hemisphere), in which the magnetic intensity cannot exceed about 900 gauss, and most probably is even smaller. 23 refs., 4 figs., 4 tabs. (author)

  19. Void formation in cold-worked type 316 stainless steel irradiated with 1-MeV protons

    International Nuclear Information System (INIS)

    Keefer, D.W.; Pard, A.G.

    1974-01-01

    Cold-worked Type 316 stainless steel was irradiated at 500 and 600 0 C with 1-MeV protons. The dependence of void formation on displacement damage, irradiation temperature, and microstructure was studied by transmission electron microscopy. Cold working delays the onset of swelling and reduces it, via a reduction in void size, at both irradiation temperatures. Inhomogeneity in the cold-worked microstructure leads to inhomogeneity in the disposition of voids. Swelling at 600 is greater than at 500 0 C; the voids are less numerous but larger at the higher temperature. No change in the cold-worked microstructure can be detected by transmission electron microscopy after 500 0 C irradiation to 23 displacements per atom. Irradiation to a comparable damage level at 600 0 C results in almost complete elimination of the cold-worked microstructure. Comparison of the results is made with data from reactor irradiation experiments

  20. Differential effects of atomic bomb irradiation in inducing major leukemia types

    International Nuclear Information System (INIS)

    Tomonaga, Masao; Matsuo, Tatsuki; Carter, R.L.

    1993-05-01

    In this report we utilize data from the additional 517 cases from the leukemia registry together with the Life Span Study (LSS) cohort data to study the effects of atomic bomb irradiation on major leukemia types. The French-American-British classification and other improved diagnostic methods were used to reclassify cases into 21 categories, including new disease entities such as adult T-cell leukemia (ATL). These categories were then grouped into four major types for analysis: (1) acute lymphocytic leukemia (ALL), (2) acute myeloid leukemia (AML) including myelodysplastic syndromes (MDS), (3) chronic myeloid leukemia (CML), and (4) OTHER types including ATL. Analyses of radiation effects were based on the updated Dosimetry System 1986(DS86). Incidence rates of all four leukemia types increased with increasing exposure level. The effects of radiation were significantly greater on the incidence of ALL and CML than on that of AML and OTHER. In the two lowest dose categories (1-49 and 50-499 mGy), estimated incidence either remained constant or increased slightly as the population of survivors aged. In the two highest dose categories (500-1,499 and ≥ 1,500 mGy). Among unexposed persons, the estimated risk of CML in Nagasaki relative to Hiroshima was significantly less than that of AML, whereas that of OTHER types was significantly greater. The time to onset of ALL, AML, and CML declined with increasing dose. The rate of decline, however, was greater for ALL and CML than for AML. The resulting differences at high doses reflect shorter incubation times for atomic-bomb-induced ALL and CML than for AML. (J.P.N.)

  1. Running Performance of a Pinning-Type Superconducting Magnetic Levitation Guide

    International Nuclear Information System (INIS)

    Okano, M; Iwamoto, T; Furuse, M; Fuchino, S; Ishii, I

    2006-01-01

    A pinning-type superconducting magnetic levitation guide with bulk high-Tc superconductors was studied for use as a goods transportation system, an energy storage system, etc. A superconducting magnetic levitation running test apparatus with a circular track of ca. 38 m length, 12 m diameter, which comprises the magnetic rail constituted by Nd-B-Fe rare-earth permanent magnets and steel plates, was manufactured to examine loss and high-speed performance of the magnetic levitation guide. Running tests were conducted in air. These tests clarify that a vehicle supported by a superconducting magnetic levitation guide runs stably at speeds greater than 42 km/h above the circular track

  2. Running Performance of a Pinning-Type Superconducting Magnetic Levitation Guide

    Science.gov (United States)

    Okano, M.; Iwamoto, T.; Furuse, M.; Fuchino, S.; Ishii, I.

    2006-06-01

    A pinning-type superconducting magnetic levitation guide with bulk high-Tc superconductors was studied for use as a goods transportation system, an energy storage system, etc. A superconducting magnetic levitation running test apparatus with a circular track of ca. 38 m length, 12 m diameter, which comprises the magnetic rail constituted by Nd-B-Fe rare-earth permanent magnets and steel plates, was manufactured to examine loss and high-speed performance of the magnetic levitation guide. Running tests were conducted in air. These tests clarify that a vehicle supported by a superconducting magnetic levitation guide runs stably at speeds greater than 42 km/h above the circular track.

  3. EL2-related defects in neutron irradiated GaAs1/sub -x/P/sub x/ alloys

    International Nuclear Information System (INIS)

    Munoz, E.; Garcia, F.; Jimenez, B.; Calleja, E.; Gomez, A.; Alcober, V.

    1985-01-01

    The generation of EL2-related defects in GaAsP alloys by fast neutron irradiation has been studied through deep level transient spectroscopy and photocapacitance techniques. After irradiation p-n junctions were not annealed at high temperatures. In the composition range x>0.4, fast neutrons generate a broad center at E/sub c/-0.7 eV that it is suggested to belong to the EL2 family. The presence of photocapacitance quenching effects has been taken as a preliminary fingerprint to make the above assignment. From computer analysis of the nonexponential transient capacitance waveforms, evidence that neutron irradiation creates a family of midgap levels, EL2-related, is found

  4. Study of boron carbide evolution under neutron irradiation

    International Nuclear Information System (INIS)

    Simeone, D.

    1999-01-01

    Owing to its high neutron efficiency, boron carbide (B 4 C) is used as a neutron absorber in control rods of nuclear plants. Its behaviour under irradiation has been extensively studied for many years. It now seems clear that brittleness of the material induced by the 10 B(n,α) 7 Li capture reaction is due to penny shaped helium bubbles associated to a high strain field around them. However, no model explains the behaviour of the material under neutron irradiation. In order to build such a model, this work uses different techniques: nuclear microprobe X-ray diffraction profile analysis and Raman and Nuclear Magnetic Resonance Spectroscopy to present an evolution model of B 4 C under neutron irradiation. The use of nuclear reactions produced by a nuclear microprobe such as the 7 Li(p,p'γ) 7 Li reaction, allows to measure lithium profile in B 4 C pellets irradiated either in Pressurised Water Reactors or in Fast Breeder Reactors. Examining such profiles enables us to describe the migration of lithium atoms out of B 4 C materials under neutron irradiation. The analysis of X-ray diffraction profiles of irradiated B 4 C samples allows us to quantify the concentrations of helium bubbles as well as the strain fields around such bubbles.Furthermore Raman spectroscopy studies of different B 4 C samples lead us to propose that under neutron irradiation. the CBC linear chain disappears. Such a vanishing of this CBC chain. validated by NMR analysis, may explain the penny shaped of helium bubbles inside irradiated B 4 C. (author)

  5. Annihilation of interstitial-type dislocation loops in {alpha}-Fe during He irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Q., E-mail: xu@rri.kyoto-u.ac.jp [Research Reactor Institute, Kyoto University, Osaka 590-0494 (Japan); Wang, Y.X. [Institute of Modern Physics, Fudan University, Shanghai 200433 (China); Katakabe, Y. [Research Institute for Applied Mechanics, Kyushu University, Fukuoka 816-8580 (Japan); Iwakiri, H. [Faculty of Education, University of the Ryukyus, Okinawa 903-0213 (Japan); Yoshida, N. [Research Institute for Applied Mechanics, Kyushu University, Fukuoka 816-8580 (Japan); Sato, K.; Yoshiie, T. [Research Reactor Institute, Kyoto University, Osaka 590-0494 (Japan)

    2011-10-01

    Interstitial-type dislocation loops were formed in Fe-9Cr alloys on irradiation with 1-MeV He ions at 673 K. However, with increasing irradiation dose, the dislocation loops shrunk. A molecular dynamics simulation was used to elucidate the mechanism of this unexpected phenomenon. The simulation shows that, although the binding energy of a self-interstitial atom to a dislocation loop is normally greater than that of a vacancy, the energy hierarchy is reversed when He atoms decorate the loop. This may indicates preferential absorption of vacancies, causing loop shrinkage at high doses, consistent with experimental observation.

  6. Annihilation of interstitial-type dislocation loops in α-Fe during He irradiation

    International Nuclear Information System (INIS)

    Xu, Q.; Wang, Y.X.; Katakabe, Y.; Iwakiri, H.; Yoshida, N.; Sato, K.; Yoshiie, T.

    2011-01-01

    Interstitial-type dislocation loops were formed in Fe-9Cr alloys on irradiation with 1-MeV He ions at 673 K. However, with increasing irradiation dose, the dislocation loops shrunk. A molecular dynamics simulation was used to elucidate the mechanism of this unexpected phenomenon. The simulation shows that, although the binding energy of a self-interstitial atom to a dislocation loop is normally greater than that of a vacancy, the energy hierarchy is reversed when He atoms decorate the loop. This may indicates preferential absorption of vacancies, causing loop shrinkage at high doses, consistent with experimental observation.

  7. Synthesis of magnetic nanoparticles: effects of polyelectrolyte concentration and pH

    Energy Technology Data Exchange (ETDEWEB)

    Urquijo, J. P., E-mail: jurquijo@fisica.udea.edu.co; Casanova, Herley; Garces, Javier; Morales, Alvaro L. [Universidad de Antioquia (Colombia)

    2011-11-15

    This study refers to the effect of sodium polyacrylate concentration (1 to 5 mass %) and pH (10 to 12) on the synthesis of magnetic nanoparticles (magnetite-maghemite) and their characterization by Moessbauer spectroscopy. The magnetic particles were obtained by coprecipitation method using iron chloride (II) and iron chloride (III) as precursor reagents and sodium polyacrylate as stabilizing agent. All samples showed Moessbauer broad resonance lines in typical doublet and sextets patterns of magnetite or maghemite with corresponding wide particle size distributions. The stability of magnetic particles was carried out by measuring particle sizes with dynamic light scattering (DLS). The z-average values for magnetic particles were in the range 24 to 590 nm and no significant change in size was observed on aging by leaving this material in air for 20 days. X-ray diffraction patterns showed characteristic peaks of the spinel structure and have an increase in their broadening as the pH decreases, effect that is dominated by the decrease in crystallite sizes. The nanoparticles showed to be magnetic at pH 12 and at room temperature.

  8. Argon Ion Irradiation Effect on the Magnetic Properties of Fe-Al2O3 Nano Granular Film

    Directory of Open Access Journals (Sweden)

    Setyo Purwanto

    2014-10-01

    Full Text Available We studied the effect of Argon (Ar ion irradiation on Fe-Al2O3 nanogranular thin film. X-ray diffraction (XRD patterns show that the ion dose might promote the growth of the Fe2O3 phase from an amorphous phase to a crystalline phase. The magnetic and magnetoresistance properties were investigated using a vibrating sample magnetometer (VSM and a four point probe (FPP. The results suggest that percolation concentration occurred at the 0.55 Fe volume fraction and with a maximum magnetoresistance (MR ratio of 3%. The present MR ratio was lower than that of previous results, which might be related to the existence of the α-Fe2O3 phase promoted by Ar ion irradiation. CEMS spectra show ion irradiation induces changes from superparamagnetic characteristics to ferromagnetic ones, which indicates the spherical growth of Fe particles in the Al2O3 matrix.

  9. Parameters concerning the preparation and performance of a magnetic microparticle antibody

    International Nuclear Information System (INIS)

    Rongsen, Shen; Ruiyun, Xing; Fengqi, Zhou; Xiuzhen, Liu; Dingquan, Wang

    1997-01-01

    We have described 'Magnetic Microparticle Antibodies and Their Application to RIAs' in a recently published paper. In this article operative parameters for the preparation of a magnetic second antibody (MSA-II) including results of purification of donkey anti-rabbit (D X R) serum by an (NH 4 ) 2 SO 4 precipitation method, rates of recovery of products in preparation of magnetic nucleus (MN, Fe 3 O 4 microparticle), in distillation of acrolein (AL) and in preparation of polyacrolein magnetic particle (PAMP), change in pH value of suspension irradiated before and after 60 Co γ-irradiation and volume of wet sediment in separation of magnetic particles by a magnetic separator, etc., as well as correlation of levels of quality control (QC) sera obtained with liquid-phase double antibody assay (LDA) and MSA-II assay during four years were supplementarily summarized. These operative parameters would be helpful to mastering the procedures for preparation and/or use of the magnetic particles. The better correlation of levels of QC sera for both the assays showed the reliability of the magnetic antibody. (author)

  10. Response change in winter-wheat types to the pathogen complex under chronic gamma-irradiation

    International Nuclear Information System (INIS)

    Budanov, V.E.; Lysenkov, V.I.; Shcherbakov, V.K.

    1975-01-01

    Disease reactions in plants that have been gamma-irradiated are discussed. Damage to different types of soft winter wheat, due to pathogenic fungi, is evaluated. The Mironovski Jubilee variety showed high resistance to the leaf form of powdery mildew, along with the opposite phenomenon of a high susceptibility to the stem form of this disease. Chronic gamma irradiation of plants of this variety increased the susceptibility to this disease

  11. Effect of 100 MeV Ag{sup +7} ion irradiation on the bulk and surface magnetic properties of Co–Fe–Si thin films

    Energy Technology Data Exchange (ETDEWEB)

    Hysen, T., E-mail: hysenthomas@gmail.com [Department of Physics, Cochin University of Science and Technology, Cochin 682 022, Kerala (India); Department of Physics, Christian College, Chengannur, Kerala 689 122 (India); Geetha, P. [Department of Physics, Cochin University of Science and Technology, Cochin 682 022, Kerala (India); Al-Harthi, Salim; Al-Omari, I.A. [Department of Physics, College of Science, Sultan Qaboos University, Al Khod 123 (Oman); Lisha, R. [Department of Physics, Cochin University of Science and Technology, Cochin 682 022, Kerala (India); Ramanujan, R.V. [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639 798 (Singapore); Sakthikumar, D. [Graduate School of Interdisciplinary New Science, Toyo University, Kawagoe (Japan); Avasthi, D.K. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110 067 (India); Anantharaman, M.R., E-mail: mra@cusat.ac.in [Department of Physics, Cochin University of Science and Technology, Cochin 682 022, Kerala (India)

    2014-12-15

    Thin films of Co–Fe–Si were vacuum evaporated on pre-cleaned float glass substrates employing thermal evaporation. The films were subsequently irradiated with 100 MeV Ag{sup +7} ions at fluences of 1×10{sup 11}, 1×10{sup 12} and 1×10{sup 13} ions/cm{sup 2}. The pristine and irradiated samples were subjected to surface analysis using Atomic Force Microscopy (AFM), Vibrating Sample Magnetometry (VSM) and Magneto Optic Kerr Effect (MOKE) measurements. The as deposited film has a root mean square roughness (Rq) of 8.9 nm and an average roughness of (Ra) 5.6 nm. Irradiation of the as deposited films with 100 MeV Ag{sup 7+} ions modifies the surface morphology. Irradiating with ions at fluences of 1×10{sup 11} ions/cm{sup 2} smoothens the mesoscopic hill-like structures, and then, at 1×10{sup 12} ions/cm{sup 2} new surface structures are created. When the fluence is further increased to 1×10{sup 13} ions/cm{sup 2} an increase in the surface roughness is observed. The MOKE loop of as prepared film indicated a squareness ratio of 0.62. As the film is irradiated with fluences of 1×10{sup 11} ions/cm{sup 2}, 1×10{sup 12} ions/cm{sup 2} and 1×10{sup 13} ions/cm{sup 2} the squareness ratio changes to 0.76, 0.8 and 0.86 respectively. This enhancement in squareness ratio towards 1 is a typical feature when the exchange interaction starts to dominates the inherent anisotropies in the system. The variation in surface magnetisation is explained based on the variations in surface roughness with swift heavy ion (SHI) irradiation. - Highlights: • We have irradiated thermally evaporated Co–Fe–Si thin films on glass substrate with 100 MeV Ag{sup +7} ions using the 15 UD Pelletron Accelerator at IUAC, New Delhi, India. • Surface morphology and magnetic characteristics of the films can be altered with ion irradiation. • It was observed that the variation in surface magnetic properties correlates well with the changes in surface morphology, further reiterating the

  12. Electron beam irradiation induces abnormal development and the stabilization of p53 protein of American serpentine leafminer, Liriomyza trifolii (Burgess)

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Hyun-Na; Yun, Seung-Hwan; Yoon, Changmann [Department of Plant Medicine, College of Agriculture, Life and Environment Sciences, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Kim, Gil-Hah, E-mail: khkim@chungbuk.ac.kr [Department of Plant Medicine, College of Agriculture, Life and Environment Sciences, Chungbuk National University, Cheongju 361-763 (Korea, Republic of)

    2012-01-15

    The American serpentine leafminer fly, Liriomyza trifolii (Burgess), is one of the most destructive polyphagous pests worldwide. In this study, we determined electron beam doses for inhibition of normal development of the leaf miner and investigated the effect of electron beam irradiation on DNA damage and p53 stability. Eggs (0-24 h old), larvae (2nd instar), puparia (0-24 h old after pupariation) and adults (24 h after emergence) were irradiated with increasing doses of electron beam irradiation (six levels between 30 and 200 Gy). At 150 Gy, the number of adults that developed from irradiated eggs, larvae and puparia was lower than in the untreated control. Fecundity and egg hatchability decreased depending on the doses applied. Reciprocal crosses between irradiated and unirradiated flies demonstrated that males were more radiotolerant than females. Adult longevity was not affected in all stages. The levels of DNA damage in L. trifolii adults were evaluated using the alkaline comet assay. Our results indicate that electron beam irradiation increased levels of DNA damage in a dose-dependent manner. Moreover, low doses of electron beam irradiation led to the rapid appearance of p53 protein within 6 h; however, it decreased after exposure to high doses (150 Gy and 200 Gy). These results suggest that electron beam irradiation induced not only abnormal development and reproduction but also p53 stability caused by DNA damage in L. trifolii. We conclude that a minimum dose of 150 Gy should be sufficient for female sterilization of L. trifolii. - Highlights: > Electron beam irradiation inhibited normal development of the leaf miner. > Electron beam irradiation inhibited normal reproduction of the leaf miner. > Electron beam irradiation increased levels of DNA damage. > Electron beam irradiation induced p53 stability.

  13. Atomic-scale structure of irradiated GaN compared to amorphised GaP and GaAs

    International Nuclear Information System (INIS)

    Ridgway, M.C.; Everett, S.E.; Glover, C.J.; Kluth, S.M.; Kluth, P.; Johannessen, B.; Hussain, Z.S.; Llewellyn, D.J.; Foran, G.J.; Azevedo, G. de M.

    2006-01-01

    We have compared the atomic-scale structure of ion irradiated GaN to that of amorphised GaP and GaAs. While continuous and homogenous amorphised layers were easily achieved in GaP and GaAs, ion irradiation of GaN yielded both structural and chemical inhomogeneities. Transmission electron microscopy revealed GaN crystallites and N 2 bubbles were interspersed within an amorphous GaN matrix. The crystallite orientation was random relative to the unirradiated epitaxial structure, suggesting their formation was irradiation-induced, while the crystallite fraction was approximately constant for all ion fluences beyond the amorphisation threshold, consistent with a balance between amorphisation and recrystallisation processes. Extended X-ray absorption fine structure measurements at the Ga K-edge showed short-range order was retained in the amorphous phase for all three binary compounds. For ion irradiated GaN, the stoichiometric imbalance due to N 2 bubble formation was not accommodated by Ga-Ga bonding in the amorphous phase or precipitation of metallic Ga but instead by a greater reduction in Ga coordination number

  14. The effect of nitrate, bicarbonate and natural organic matter on the degradation of sunscreen agent p-aminobenzoic acid by simulated solar irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Mao, Liang, E-mail: lmao@nju.edu.cn [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Meng, Cui; Zeng, Chao; Ji, Yuefei [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Yang, Xi, E-mail: yangxi@nju.edu.cn [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361005 (China); Gao, Shixiang [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China)

    2011-11-15

    Our experiments revealed that a model sunscreen agent, p-aminobenzoic acid (PABA), can be effectively transformed through reactions that are mediated by simulated solar irradiation. We systematically explored the effects of nitrate ions, bicarbonate and different types of natural organic matter (NOM) on the degradation of PABA by simulated solar irradiation. Experimental data suggest that these components ubiquitous in nature water have different influence on the rates of the photoinduced removal of PABA. Products were extracted and analyzed using LC/MS and a total of four products probably resulting from {center_dot}OH and {center_dot}NO{sub 2} radicals attack were identified and the possible reaction pathways were proposed. The findings in this study provide useful information for understanding the environmental transformation of sunscreen agent in aquatic system. - Highlights: {yields} In this study, we found that p-aminobenzoic acid (PABA) can be removed by simulated solar irradiation from water. {yields} Influence of environmental components on the photodegradation of PABA was further studied. {yields} We verified using LC/MS that PABA was transformed into four compounds. {yields} We proposed the possible reaction pathways probably resulting from {center_dot}OH and {center_dot}NO{sub 2} radicals attack to PABA.

  15. The effect of nitrate, bicarbonate and natural organic matter on the degradation of sunscreen agent p-aminobenzoic acid by simulated solar irradiation

    International Nuclear Information System (INIS)

    Mao, Liang; Meng, Cui; Zeng, Chao; Ji, Yuefei; Yang, Xi; Gao, Shixiang

    2011-01-01

    Our experiments revealed that a model sunscreen agent, p-aminobenzoic acid (PABA), can be effectively transformed through reactions that are mediated by simulated solar irradiation. We systematically explored the effects of nitrate ions, bicarbonate and different types of natural organic matter (NOM) on the degradation of PABA by simulated solar irradiation. Experimental data suggest that these components ubiquitous in nature water have different influence on the rates of the photoinduced removal of PABA. Products were extracted and analyzed using LC/MS and a total of four products probably resulting from ·OH and ·NO 2 radicals attack were identified and the possible reaction pathways were proposed. The findings in this study provide useful information for understanding the environmental transformation of sunscreen agent in aquatic system. - Highlights: → In this study, we found that p-aminobenzoic acid (PABA) can be removed by simulated solar irradiation from water. → Influence of environmental components on the photodegradation of PABA was further studied. → We verified using LC/MS that PABA was transformed into four compounds. → We proposed the possible reaction pathways probably resulting from ·OH and ·NO 2 radicals attack to PABA.

  16. Classification System for Identifying Women at Risk for Altered Partial Breast Irradiation Recommendations After Breast Magnetic Resonance Imaging

    International Nuclear Information System (INIS)

    Kowalchik, Kristin V.; Vallow, Laura A.; McDonough, Michelle; Thomas, Colleen S.; Heckman, Michael G.; Peterson, Jennifer L.; Adkisson, Cameron D.; Serago, Christopher; McLaughlin, Sarah A.

    2013-01-01

    Purpose: To study the utility of preoperative breast MRI for partial breast irradiation (PBI) patient selection, using multivariable analysis of significant risk factors to create a classification rule. Methods and Materials: Between 2002 and 2009, 712 women with newly diagnosed breast cancer underwent preoperative bilateral breast MRI at Mayo Clinic Florida. Of this cohort, 566 were retrospectively deemed eligible for PBI according to the National Surgical Adjuvant Breast and Bowel Project Protocol B-39 inclusion criteria using physical examination, mammogram, and/or ultrasound. Magnetic resonance images were then reviewed to determine their impact on patient eligibility. The patient and tumor characteristics were evaluated to determine risk factors for altered PBI eligibility after MRI and to create a classification rule. Results: Of the 566 patients initially eligible for PBI, 141 (25%) were found ineligible because of pathologically proven MRI findings. Magnetic resonance imaging detected additional ipsilateral breast cancer in 118 (21%). Of these, 62 (11%) had more extensive disease than originally noted before MRI, and 64 (11%) had multicentric disease. Contralateral breast cancer was detected in 28 (5%). Four characteristics were found to be significantly associated with PBI ineligibility after MRI on multivariable analysis: premenopausal status (P=.021), detection by palpation (P<.001), first-degree relative with a history of breast cancer (P=.033), and lobular histology (P=.002). Risk factors were assigned a score of 0-2. The risk of altered PBI eligibility from MRI based on number of risk factors was 0:18%; 1:22%; 2:42%; 3:65%. Conclusions: Preoperative bilateral breast MRI altered the PBI recommendations for 25% of women. Women who may undergo PBI should be considered for breast MRI, especially those with lobular histology or with 2 or more of the following risk factors: premenopausal, detection by palpation, and first-degree relative with a history of

  17. Exciton in vertically coupled type II quantum dots in threading magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza-Cantillo, J., E-mail: jhofry@gmail.com [Group of Investigation in Condensed Matter Theory, Universidad del Magdalena, Carrera 32 No 22-08, Santa Marta (Colombia); Universidad de la Guajira, Riohacha (Colombia); Escorcia-Salas, G. Elizabeth, E-mail: elizabethescorcia@gmail.com [Group of Investigation in Condensed Matter Theory, Universidad del Magdalena, Carrera 32 No 22-08, Santa Marta (Colombia); Mikhailov, I.D., E-mail: mikhail2811@gmail.com [Universidad Industrial de Santander, A. A. 678, Bucaramanga (Colombia); Sierra-Ortega, J., E-mail: jsierraortega@gmail.com [Group of Investigation in Condensed Matter Theory, Universidad del Magdalena, Carrera 32 No 22-08, Santa Marta (Colombia)

    2014-11-15

    We analyze the energy spectrum of a neutral exciton confined in a semiconductor heterostructure formed by two vertically coupled axially symmetrical type II quantum dots located close to each other. The electron in the structure is mainly located inside dots tunneling between them while the hole generally is placed in the exterior region close to the symmetry axis. Solutions of the Schrödinger equation are obtained by a variational separation of variables in the adiabatic limit. Numerical results are presented for the energies of bonding and anti-bonding lowest-lying of the exciton states and for the density of states for different InP/GaInP quantum dots' morphologies and the magnetic field strength values.

  18. Postirradiation examination of capsules P13R and P13S

    International Nuclear Information System (INIS)

    Scott, C.B.; Harmon, D.P.; Holzgraf, J.F.

    1976-01-01

    Capsules P13R and P13S were the seventh and eighth in a series of irradiation tests conducted under the ERDA-sponsored HTGR Fuels and Core Development Program. Reference type LHTGR fuel fabricated with a broad spectrum of property and process variables was irradiated to extreme temperature and fluence conditions. Postirradiation examination revealed that the bonded fuel rods exhibited good stability after irradiation to fast neutron fluences of 12.4 x 10 21 n/cm 2 (E greater than 0.18 MeV), which is 55 percent beyond the LHTGR peak design fast neutron fluence of 8.0 x 10 21 n/cm 2 . Thermal cycling to high temperatures did not adversely affect fuel rod integrity. Particle batches with coating designs representative of the design requirements envisioned for the LHTGR exhibited excellent irradiation performance. Ten batches of fissile and fertile particles were irradiated without coating failure to fast neutron exposures which exceeded the LHTGR peak design exposure by 35 to 52 percent. Capsules P13R and P13S were considered to be very successful qualification tests of LHTGR fuel components. These results provided a substantial data base for the LHTGR Fuel Product Specification and Performance Models used in HTGR core design studies, and demonstrated the excellent irradiation performance of reference LHTGR fuel to well beyond peak design exposures

  19. Effect of gamma irradiation on Burkholderia thailandensis (Burkholderia pseudomallei surrogate) survival under combinations of pH and NaCl

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Yohan; Kim, Jae-Hun; Byun, Myung-Woo [Team for Radiation Food Science and Biotechnology, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, Jeollabuk 580-185 (Korea, Republic of); Choi, Kyoung-Hee [Department of Oral Microbiology, College of Dentistry, Wonkwang University, Iksan, Jeollabuk 570-749 (Korea, Republic of); Lee, Ju-Woon, E-mail: sjwlee@kaeri.re.k [Team for Radiation Food Science and Biotechnology, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, Jeollabuk 580-185 (Korea, Republic of)

    2010-04-15

    This study evaluated the effect of gamma irradiation on Burkholderia thailandensis (Burkholderia pseudomallei surrogate; potential bioterrorism agent) survival under different levels of NaCl and pH. B. thailandensis in Luria Bertani broth supplemented with NaCl (0-3%), and pH-adjusted to 4-7 was treated with gamma irradiation (0-0.5 kGy). Surviving cell counts of bacteria were then enumerated on tryptic soy agar. Data for the cell counts were also used to calculate D{sub 10} values (the dose required to reduce 1 log CFU/mL of B. thailandensis). Cell counts of B. thailandensis were decreased (P<0.05) as irradiation dose increased, and no differences (P>=0.05) in cell counts of the bacteria were observed among different levels of NaCl and pH. D{sub 10} values ranged from 0.04 to 0.07 kGy, regardless of NaCl and pH level. These results indicate that low doses of gamma irradiation should be a useful treatment in decreasing the potential bioterrorism bacteria, which may possibly infect humans through foods.

  20. Dependence of irradiation creep on temperature and atom displacements in 20% cold worked type 316 stainless steel

    International Nuclear Information System (INIS)

    Gilbert, E.R.

    1976-04-01

    Irradiation creep studies with pressurized tubes of 20 percent cold worked Type 316 stainless steel were conducted in EBR-2. Results showed that as atom displacements are extended above 5 dpa and temperatures are increased above 375 0 C, the irradiation induced creep rate increases with both increasing atom displacements and increasing temperature. The stress exponent for irradiation induced creep remained near unity. Irradiation-induced effective creep strains up to 1.8 percent were observed without specimen failure. 13 figures

  1. EFFECT OF IRRADIATION AND PACKAGING MATERIALS TYPES ON SHELF-LIFE AND QUALITY ATTRIBUTES OF MINCED MEAT DURING COLD STORAGE

    International Nuclear Information System (INIS)

    OSHEBA, A.S.; NAGY, KH.S.; ANWAR, M.M.

    2008-01-01

    Minced meat is considered one of the most meat products that exposed to contamination which led to many changes in its quality and reduced its shelf-life.Therefore, this investigation was carried out to extend the shelf-life of minced meat for consumption and maintaining its quality during cold storage by using irradiation with various doses (3, 6 and 9 kGy) and different packing materials. The results indicated that irradiation,especially at 3 and 6 kGy, had no effect on chemical composition and some physical properties of minced meat. On the other hand, pH values of all irradiated samples were slightly decreased with decreasing irradiation doses.Irradiation at the highest dose used, i.e. 9 kGy, slightly increased total volatile nitrogen (TVN) of minced meat. Thiobarbituric acid (TBA) value of irradiated samples was tended to increase with increasing irradiation dose from 3 to 9 kGy either directly after irradiation or during storage.Regardless of irradiation effect on TVN and TBA values at zero time, there were no marked differences in TVN and TBA values of irradiated minced meat according to differentiate packaging materials (PE, PA/PE and PET/Al/PE). During cold storage, the TVN and TBA values of all minced meat samples either non-irradiated or irradiated were progressively increased as the time of cold storage increased. The higher increasing rate in TVN and TBA of irradiated samples was recorded for samples packaged in PE (one layer) followed by PA/PE (two layers) and finally PET/Al/PE (three layers) at the same irradiation dose. Irradiation of minced meat with 3 kGy reduced the counts of total bacteria, coliform bacteria, Staphylococcus aureus and yeasts and molds counts as well as eliminating Salmonella spp. Irradiation doses of 6 and 9 kGy completely eliminated coliform bacteria, Staphylococcus aureus and yeasts and molds. Also, type of packaging materials which used had no effect on counts of all studied microorganisms. Irradiation of minced meat with

  2. Simulation of irradiation hardening of Zircaloy within plate-type dispersion nuclear fuel elements

    Science.gov (United States)

    Jiang, Yijie; Wang, Qiming; Cui, Yi; Huo, Yongzhong; Ding, Shurong

    2011-06-01

    Within plate-type dispersion nuclear fuel elements, the metal matrix and cladding attacked continuously by fast neutrons undergo irradiation hardening, which might have remarkable effects upon the mechanical behaviors within fuel elements. In this paper, with the irradiation hardening effect of metal materials mainly considered together with irradiation growth effect of the cladding, the three-dimensional large-deformation constitutive relations for the metal matrix and cladding are developed. The method of virtual temperature increase in the previous studies is further developed to model the irradiation swelling of fuel particles; the method of anisotropic thermal expansion is introduced to model irradiation growth of the cladding; and a method of multi-step-temperature loading is proposed to simulate the coupling features of irradiation-induced swelling of the fuel particles together with irradiation growth of the cladding. Above all, based on the developed relationship between irradiation growth at certain burnup and the loaded virtual temperatures, with considering that certain burnup corresponds to certain fast neutron fluence, the time-dependent constitutive relation due to irradiation hardening effect is replaced by the virtual-temperature-dependent one which is introduced into the commercial software to simulate the irradiation hardening effects of the matrix and cladding. Numerical simulations of the irradiation-induced mechanical behaviors are implemented with the finite element method in consideration of the micro-structure of the fuel meat. The obtained results indicate that when the irradiation hardening effects are introduced into the constitutive relations of the metal matrix and cladding: (1) higher maximum Mises stresses for certain burnup at the matrix exist with the equivalent plastic strains remaining almost the same at lower burnups; (2) the maximum Mises stresses for certain burnup at the cladding are enhanced while the maximum equivalent

  3. Simulation of irradiation hardening of Zircaloy within plate-type dispersion nuclear fuel elements

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Yijie; Wang Qiming; Cui Yi; Huo Yongzhong [Department of Mechanics and Engineering Science, Fudan University, Shanghai 200433 (China); Ding Shurong, E-mail: dsr1971@163.com [Department of Mechanics and Engineering Science, Fudan University, Shanghai 200433 (China)

    2011-06-15

    Within plate-type dispersion nuclear fuel elements, the metal matrix and cladding attacked continuously by fast neutrons undergo irradiation hardening, which might have remarkable effects upon the mechanical behaviors within fuel elements. In this paper, with the irradiation hardening effect of metal materials mainly considered together with irradiation growth effect of the cladding, the three-dimensional large-deformation constitutive relations for the metal matrix and cladding are developed. The method of virtual temperature increase in the previous studies is further developed to model the irradiation swelling of fuel particles; the method of anisotropic thermal expansion is introduced to model irradiation growth of the cladding; and a method of multi-step-temperature loading is proposed to simulate the coupling features of irradiation-induced swelling of the fuel particles together with irradiation growth of the cladding. Above all, based on the developed relationship between irradiation growth at certain burnup and the loaded virtual temperatures, with considering that certain burnup corresponds to certain fast neutron fluence, the time-dependent constitutive relation due to irradiation hardening effect is replaced by the virtual-temperature-dependent one which is introduced into the commercial software to simulate the irradiation hardening effects of the matrix and cladding. Numerical simulations of the irradiation-induced mechanical behaviors are implemented with the finite element method in consideration of the micro-structure of the fuel meat. The obtained results indicate that when the irradiation hardening effects are introduced into the constitutive relations of the metal matrix and cladding: (1) higher maximum Mises stresses for certain burnup at the matrix exist with the equivalent plastic strains remaining almost the same at lower burnups; (2) the maximum Mises stresses for certain burnup at the cladding are enhanced while the maximum equivalent

  4. Model of deep centers formation and reactions in electron irradiated InP

    International Nuclear Information System (INIS)

    Sibille, A.; Suski, J.; Gilleron, M.

    1986-01-01

    We present a model of the production of deep centers and their reactions following electron irradiations in InP. We propose that the dominant hole traps in p-InP and electron traps in p + n InP junctions are complexes between shallow acceptors and a common intrinsic entity, the phosphorus interstitial or vacancy. The reactions observed below and above room temperature are then due to a local mobility of this entity, which can be obtained as well by thermal as by electronic stimulation of the reactions. This model implies the long-range migration (at least down to 16 K) of this entity, and explains the strongly different behavior of n-InP compared to p-InP samples

  5. Post-irradiation pericardial malignant mesothelioma with deletion of p16: a case report.

    Science.gov (United States)

    Naeini, Yalda B; Arcega, Ramir; Hirschowitz, Sharon; Rao, Nagesh; Xu, Haodong

    2018-02-01

    Malignant mesotheliomas are rather uncommon neoplasms associated primarily with asbestos exposure; however, they may also arise as second primary malignancies after radiation therapy, with a latency period of 15-25 years. Numerous studies have reported an association between pleural malignant mesothelioma and chest radiation performed for other malignancies; on the other hand, post-irradiation mesotheliomas of the pericardium have been reported in only a few published cases to date, and no homozygous deletion of 9p21 has been described in such cases. We report the case of a 48-year-old man with a history of Hodgkin's lymphoma and no prior asbestos exposure who developed pericardial malignant epithelioid mesothelioma. We further discuss the cytologic, histologic, immunophenotypic, and fluorescence in situ hybridization findings in this case. To our knowledge, this is the first well-documented case of post-radiation pericardial malignant mesothelioma showing homozygous deletion of 9p21. Homozygous deletion of 9p21, the locus harboring the p16 gene, is present in post-irradiation pericardial malignant mesothelioma.

  6. The effect of fast particles' irradiation on electrooptical properties of GaP LEDs

    International Nuclear Information System (INIS)

    Gontaruk, O.; Kovalenko, A.; Malyj, E.; Petrenko, I.; Pinkovska, M.; Polivtcev, L.; Tartachnyk, V.

    2013-01-01

    The electrooptical properties of industrial AL 102 GaP light-emitting diodes (LEDs) irradiated with fast particles have been studied. 2 MeV electrons and fast reactor neutrons were used and devices' microplsma emitting, current-voltage and capacitance-voltage characteristics were measured. It was shown that electron irradiation in the range (2-5)10 16 cm -2 leads to the drop of microplasma emitting intensity, decrease of capacity and reverse currents and increase of reverse bias. The annealing study of current-voltage characteristics after neutron irradiation of diodes confirms the assumption about prevailing radiation influence on diode base due to induce of deep levels. (authors)

  7. Evolution of plant P-type ATPases

    Directory of Open Access Journals (Sweden)

    Christian N.S. Pedersen

    2012-02-01

    Full Text Available Five organisms having completely sequenced genomes and belonging to all major branches of green plants (Viridiplantae were analyzed with respect to their content of P-type ATPases encoding genes. These were the chlorophytes Ostreococcus tauria and Chlamydomonas reinhardtii, and the streptophytes Physcomitrella patens (a moss, Selaginella moellendorffii (a primitive vascular plant, and Arabidopsis thaliana (a model flowering plant. Each organism contained sequences for all five subfamilies of P-type ATPases. Our analysis demonstrates when specific subgroups of P-type ATPases disappeared in the evolution of Angiosperms. Na/K-pump related P2C ATPases were lost with the evolution of streptophytes whereas Na+ or K+ pumping P2D ATPases and secretory pathway Ca2+-ATPases remained until mosses. An N-terminally located calmodulin binding domain in P2B ATPases can only be detected in pumps from Streptophytae, whereas, like in animals, a C-terminally localized calmodulin binding domain might be present in chlorophyte P2B Ca2+-ATPases. Chlorophyte genomes encode P3A ATPases resembling protist plasma membrane H+-ATPases and a C-terminal regulatory domain is missing. The complete inventory of P-type ATPases in the major branches of Viridiplantae is an important starting point for elucidating the evolution in plants of these important pumps.

  8. A Novel High-Precision Digital Tunneling Magnetic Resistance-Type Sensor for the Nanosatellites’ Space Application

    Directory of Open Access Journals (Sweden)

    Xiangyu Li

    2018-03-01

    Full Text Available Micro-electromechanical system (MEMS magnetic sensors are widely used in the nanosatellites field. We proposed a novel high-precision miniaturized three-axis digital tunneling magnetic resistance-type (TMR sensor. The design of the three-axis digital magnetic sensor includes a low-noise sensitive element and high-performance interface circuit. The TMR sensor element can achieve a background noise of 150 pT/Hz1/2 by the vertical modulation film at a modulation frequency of 5 kHz. The interface circuit is mainly composed of an analog front-end current feedback instrumentation amplifier (CFIA with chopper structure and a fully differential 4th-order Sigma-Delta (ΣΔ analog to digital converter (ADC. The low-frequency 1/f noise of the TMR magnetic sensor are reduced by the input-stage and system-stage chopper. The dynamic element matching (DEM is applied to average out the mismatch between the input and feedback transconductor so as to improve the gain accuracy and gain drift. The digital output is achieved by a switched-capacitor ΣΔ ADC. The interface circuit is implemented by a 0.35 μm CMOS technology. The performance test of the TMR magnetic sensor system shows that: at a 5 V operating voltage, the sensor can achieve a power consumption of 120 mW, a full scale of ±1 Guass, a bias error of 0.01% full scale (FS, a nonlinearity of x-axis 0.13% FS, y-axis 0.11% FS, z-axis 0.15% FS and a noise density of x-axis 250 pT/Hz1/2 (at 1 Hz, y-axis 240 pT/Hz1/2 (at 1 Hz, z-axis 250 pT/Hz1/2 (at 1 Hz, respectively. This work has a less power consumption, a smaller size, and higher resolution than other miniaturized magnetometers by comparison.

  9. Low-frequency photocurrent oscillations in InP in magnetic field

    International Nuclear Information System (INIS)

    Slobodchikov, S.V.; Salikhov, Kh.M.; Kovalevskaya, G.G.

    1994-01-01

    Results of investigations of magnetic field effect on the oscillating photocurrent in InP crytals are presented. It is shown that the magnetic field plays the part of an additional source of photocarrier injection in the sample bulk. 3 refs., 2 figs

  10. WE-D-17A-04: Magnetically Focused Proton Irradiation of Small Volume Targets

    Energy Technology Data Exchange (ETDEWEB)

    McAuley, G; Slater, J [Loma Linda University, Loma Linda, CA (United States); Wroe, A [Loma Linda University Medical Center, Loma Linda, CA (United States)

    2014-06-15

    Purpose: To explore the advantages of magnetic focusing for small volume proton irradiations and the potential clinical benefits for radiosurgery targets. The primary goal is to create narrow elongated proton beams of elliptical cross section with superior dose delivery characteristics compared to current delivery modalities (eg, collimated beams). In addition, more general beam shapes are also under investigation. Methods: Two prototype magnets consisting of 24 segments of samarium-cobalt (Sm2Co17) permanent magnetic material adhered into hollow cylinders were manufactured for testing. A single focusing magnet was placed on a positioning track on our Gantry 1 treatment table and 15 mm diameter proton beams with energies and modulation relevant to clinical radiosurgery applications (127 to 186 MeV, and 0 to 30 mm modulation) were delivered to a terminal water tank. Beam dose distributions were measured using a PTW diode detector and Gafchromic EBT2 film. Longitudinal and transverse dose profiles were analyzed and compared to data from Monte Carlo simulations analogous to the experimental setup. Results: The narrow elongated focused beam spots showed high elliptical symmetry indicating high magnet quality. In addition, when compared to unfocused beams, peak-to-entrance depth dose ratios were 11 to 14% larger (depending on presence or extent of modulation), and minor axis penumbras were 11 to 20% smaller (again depending on modulation) for focused beams. These results suggest that the use of rare earth magnet assemblies is practical and could improve dose-sparing of normal tissue and organs at risk while delivering enhanced dose to small proton radiosurgery targets. Conclusion: Quadrapole rare earth magnetic assemblies are a promising and inexpensive method to counteract particle out scatter that tends to degrade the peak to entrance performance of small field proton beams. Knowledge gained from current experiments will inform the design of a prototype treatment

  11. Addressing of LnCaP Cell Using Magnetic Particles Assisted Impedimetric Microelectrode.

    Science.gov (United States)

    Nguyen, Dung Thi Xuan; Tran, Trong Binh; Nguyen, Phuong-Diem; Min, Junhong

    2016-03-01

    In this study, we provide a facile, effective technique for a simple isolation and enrichment of low metastatic prostate tumor cell LNCaP using biocompatible, magnetic particles asissted impedimetric sensing system. Hydrophobic cell membrane anchors (BAM) were generated onto magnetic particles which diameters vary from 50 nm to 5 μm and were used to capture LNCaP cells from the suspension. Finally, magnetic particle-LNCaP complex were addressed onto the surface of the interdigitated microelectrode (IDM). Cell viability was monitored by our laboratory developed-technique Electrical Cell Substrate Impedance Sensing (ECIS). The results reavealed that 50 nm-magnetic particles showed best performance in terms of cell separation and cell viability. This technique provides a simple and efficient method for the direct addressing of LNCaP cell on the surface and enhances better understanding of cell behavior for cancer management in the near future.

  12. A magnetic resonance imaging study on changes in rat mandibular bone marrow and pulp tissue after high-dose irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Wan; Lee, Byung Do [Dept. of Oral and Maxillofacial Radiology and Wonkwang Dental Research Institute, College of Dentistry, Wonkwang University, Iksan (Korea, Republic of); Lee, Kang Kyoo [Dept. of Radiation Oncology, School of Medicine, Wonkwang University, Iksan (Korea, Republic of); Koh, Kwang Joon [Dept. of Oral and Maxillofacial Radiology, School of Dentistry and Institute of Oral Bioscience, Chonbuk National University, Jeonju (Korea, Republic of)

    2014-03-15

    This study was designed to evaluate whether magnetic resonance imaging (MRI) is appropriate for detecting early changes in the mandibular bone marrow and pulp tissue of rats after high-dose irradiation. The right mandibles of Sprague-Dawley rats were irradiated with 10 Gy (Group 1, n=5) and 20 Gy (Group 2, n=5). Five non-irradiated animals were used as controls. The MR images of rat mandibles were obtained before irradiation and once a week until week 4 after irradiation. From the MR images, the signal intensity (SI) of the mandibular bone marrow and pulp tissue of the incisor was interpreted. The MR images were compared with the histopathologic findings. The SI of the mandibular bone marrow had decreased on T2-weighted MR images. There was little difference between Groups 1 and 2. The SI of the irradiated groups appeared to be lower than that of the control group. The histopathologic findings showed that the trabecular bone in the irradiated group had increased. The SI of the irradiated pulp tissue had decreased on T2-weighted MR images. However, the SI of the MR images in Group 2 was high in the atrophic pulp of the incisor apex at week 2 after irradiation. These patterns seen on MRI in rat bone marrow and pulp tissue were consistent with histopathologic findings. They may be useful to assess radiogenic sclerotic changes in rat mandibular bone marrow.

  13. Effects of low intensity laser acupoint irradiation on inhibiting islet beta-cell apoptosis in rats with type 2 diabetes

    Science.gov (United States)

    Xiong, Guoxin; Xiong, Leilei; Li, Xinzhong

    2016-09-01

    To investigate the effects of low intensity semiconductor laser acupoint irradiation on inhibiting islet beta-cell apoptosis in rats with type 2 diabetes, a method using a high-fat diet and low-dose intraperitoneal injections of streptozotocin established a type 2 diabetes mellitus rat model. Model rats were randomly divided into a laser acupoint irradiation group, rosiglitazone control group, and placebo group; each group had 10 rats. In addition, 10 normal male rats were selected for the normal control group. The Housanli, Neiting and Yishu acupoints of the rats in the laser acupoint irradiation group were irradiated with a 10 mW semiconductor laser; each point was irradiated for 15 min, once every 2 d over 28 d, for a total of 14 episodes of irradiation. The rosiglitazone group rats were given rosiglitazone (0.2 mg kg-1) intragastrically; the placebo group rats were given 0.9% brine (0.2 mg kg-1) intragastrically, once daily, for four consecutive weeks. The change of fasting blood glucose was determined before and after each treatment. The islet beta-cell apoptosis was determined. The islet beta-cell apoptosis rates of the laser acupoint irradiation group and the rosiglitazone group were significantly lower than the rate of the placebo group. Even though the rate was lower in the laser acupoint irradiation group than in the rosiglitazone group, there was no significant difference between them. It is shown that acupoint irradiation with a semiconductor laser can effectively inhibit islet beta-cell apoptosis in rats with type 2 diabetes.

  14. Performance of silicon pad detectors after mixed irradiations with neutrons and fast charged hadrons

    Energy Technology Data Exchange (ETDEWEB)

    Kramberger, G. [Jozef Stefan Institute, Department of Physics, University of Ljubljana, Jamova 39, SI-1000 Ljubljana (Slovenia)], E-mail: Gregor.Kramberger@ijs.si; Cindro, V.; Dolenc, I.; Mandic, I.; Mikuz, M.; Zavrtanik, M. [Jozef Stefan Institute, Department of Physics, University of Ljubljana, Jamova 39, SI-1000 Ljubljana (Slovenia)

    2009-10-11

    A large set of silicon pad detectors produced on MCz and FZ wafer of p- and n-type was irradiated in two steps, first by fast charged hadrons followed by reactor neutrons. In this way the irradiations resemble the real irradiation fields at LHC. After irradiations controlled annealing started in steps during which the evolution of full depletion voltage, leakage current and charge collection efficiency was monitored. The damage introduced by different irradiation particles was found to be additive. The most striking consequence of that is a decrease of the full depletion voltage for n-type MCz detectors after additional neutron irradiation. This confirms that effective donors introduced by charged hadron irradiation are compensated by acceptors from neutron irradiation.

  15. Performance of silicon pad detectors after mixed irradiations with neutrons and fast charged hadrons

    International Nuclear Information System (INIS)

    Kramberger, G.; Cindro, V.; Dolenc, I.; Mandic, I.; Mikuz, M.; Zavrtanik, M.

    2009-01-01

    A large set of silicon pad detectors produced on MCz and FZ wafer of p- and n-type was irradiated in two steps, first by fast charged hadrons followed by reactor neutrons. In this way the irradiations resemble the real irradiation fields at LHC. After irradiations controlled annealing started in steps during which the evolution of full depletion voltage, leakage current and charge collection efficiency was monitored. The damage introduced by different irradiation particles was found to be additive. The most striking consequence of that is a decrease of the full depletion voltage for n-type MCz detectors after additional neutron irradiation. This confirms that effective donors introduced by charged hadron irradiation are compensated by acceptors from neutron irradiation.

  16. Alignment of dipole magnet in micro-beam line of HIRFL

    International Nuclear Information System (INIS)

    Wang Shaoming; Chen Wenjun; Yang Shengli; Cai Guozhu; Guo Yizhen; Zhou Guangming; Man Kaidi; Song Mingtao

    2010-01-01

    Microbeam irradiation facility is an experiment platform, which can reduce the beam-spot on the irradiated sample to micrometer level, and can accurately locate and count the radioactive particles. It is a powerful research tool for the irradiation material science, irradiation biology, irradiation biomedicine and micro mechanical machining. The microbeam irradiation facility requires the precise work for installation and alignment. These conditions make magnet's change for directions and positions because the location space of dipole magnets in micro-beam line of HIRFL (Heavy Ion Research Facility in Lanzhou) is very small. It is a challenge for the installation and alignment work of magnets. It was solved by transforming coordinates of benchmarks of magnets, which controlled the error of magnet setup within error tolerance range. (authors)

  17. ESR investigation of radicals formed in γ-irradiated vinylidene fluoride based copolymer: P(VDF-co-HFP)

    International Nuclear Information System (INIS)

    Dumas, Ludovic; Albela, Belén; Bonneviot, Laurent; Portinha, Daniel; Fleury, Etienne

    2013-01-01

    Samples of copolymer based on vinylidene fluoride and hexafluoropropene P(VDF-co-HFP) were exposed to γ-radiation performed under an inert atmosphere and the total amount of radicals was quantified by electron spin resonance spectroscopy (ESR). An in-depth study of recorded ESR spectra allowed the identification of several types of radical species formed during radiolysis. Starting from an ESR simulation model established for irradiated PVDF, seven radical species have been identified in the case of P(VDF-co-HFP): five of them are related to the VDF units while the two others are derived from the HFP unit. The model used to simulate the complex superimposed ESR signals is presented. The proportions of each species are discussed and correlated to the amount of HFP units contained in the copolymer, and to the stability of each species depending on their local environment. Furthermore, the evolution of radical density with radiation dose and the decay resulting from annealing at a given temperature are presented. Corresponding spectral evolution shows the progressive predominance of most stable species. - Highlights: ► ESR signal of γ-irradiated P(vinylidene fluoride-co-hexafluoropropene) containing 6 wt% of hexafluoropropene is modeled. ► The formation of seven major radical species is proposed for the first time. ► Despite a low comonomer content, 43% of radicals are localized on hexafluoropropene. ► Effect of dose and annealing highlight radical stability. ► Radical stability is found to depend on both chemical environment and chain location

  18. Inhibition of cyclobutane pyrimidine dimer formation in epidermal p53 gene of UV-irradiated mice by alpha-tocopherol

    International Nuclear Information System (INIS)

    Chen, W.; Barthelman, M.; Martinez, J.; Alberts, D.; Gensler, H.L.

    1997-01-01

    Mutations or alterations in the p53 gene have been observed in 50-100% of ultraviolet light (UV)-induced squamous cell carcinoma in humans and animals. Most of the mutations occurred at dipyrimidine sequences, suggesting that pyrimidine dimers in the p53 gene play a role in the pathogenesis of cutaneous squamous cell carcinoma. We previously showed that topical alpha-tocopherol prevents UV-induced skin carcinogenesis in the mouse. In the present study we asked whether topical alpha-tocopherol reduces the level of UV-induced cyclobutane pyrimidine dimers in the murine epidermal p53 gene. Mice received six dorsal applications of 25 mg each of alpha-tocopherol, on alternate days, before exposure to 500 J/m2 of UV-B irradiation. Mice were killed at selected times after irradiation. The level of dimers in the epidermal p53 gene was measured using the T4 endonuclease V assay with quantitative Southern hybridization. Topical alpha-tocopherol caused a 55% reduction in the formation of cyclobutane pyrimidine dimers in the epidermal p53 gene. The rate of reduction of pyrimidine dimers between 1 and 10 hours after irradiation was similar in UV-irradiated mice, regardless of alpha-tocopherol treatment. Therefore, the lower level of cyclobutane pyrimidine dimers in UV-irradiated mice treated with alpha-tocopherol than in control UV-irradiated mice resulted from the prevention of formation of the dimers, and not from enhanced repair of these lesions. Our results indicate that alpha-tocopherol acts as an effective sunscreen in vivo, preventing the formation of premutagenic DNA lesions in a gene known to be important in skin carcinogenesis

  19. Hair dosimetry following neutron irradiation.

    Science.gov (United States)

    Lebaron-Jacobs, L; Gaillard-Lecanu, E; Briot, F; Distinguin, S; Boisson, P; Exmelin, L; Racine, Y; Berard, P; Flüry-Herard, A; Miele, A; Fottorino, R

    2007-05-01

    Use of hair as a biological dosimeter of neutron exposure was proposed a few years ago. To date, the (32)S(n,p)(32)P reaction in hair with a threshold of 2.5 MeV is the best choice to determine the fast neutron dose using body activation. This information is essential with regards to the heterogeneity of the neutron transfer to the organism. This is a very important parameter for individual dose reconstruction from the surface to the deeper tissues. This evaluation is essential to the adapted management of irradiated victims by specialized medical staff. Comparison exercises between clinical biochemistry laboratories from French sites (the CEA and COGEMA) and from the IRSN were carried out to validate the measurement of (32)P activity in hair and to improve the techniques used to perform this examination. Hair was placed on a phantom and was irradiated at different doses in the SILENE reactor (Valduc, France). Different parameters were tested: variation of hair type, minimum weight of hair sample, hair wash before measurement, delivery period of results, and different irradiation configurations. The results obtained in these comparison exercises by the different laboratories showed an excellent correlation. This allowed the assessment of a dose-activity relationship and confirmed the feasibility and the interest of (32)P measurement in hair following fast neutron irradiation.

  20. Average cross-sections for /n, p/ reactions on calcium in a fission-type reactor spectrum

    International Nuclear Information System (INIS)

    Bruggeman, A.; Maenhaut, W.; Hoste, J.

    1974-01-01

    The average cross-section in a fission-type reactor spectrum sigmasub(F) was experimentally determined for the reactions 42 Ca/n,p/ 42 K, 43 Ca/n,p/ 43 K and 44 Ca/n,p/ 44 K. Calcium carbonate samples and fast neutron flux monitors were irradiated with and without cadmium shielding in the Thetis reactor (Institute for Nuclear Sciences, Rijksuniversiteit Gent). The potassium activities induced in the calcium carbonate samples were separated and purified by tetraphenylborate precipitation, after which they were measured with a Ge/Li/-detector of calibrated detection efficiency. On the basis of sigmasub(F)=0.64 mb for the reaction 27 Al/n,α/ 24 Na, the average cross-sections were as follows: 42 Ca/n,p/ 42 K: 2.82+-0.07 mb; 43 Ca/n,p/ 43 K: 1.89+-0.05 mb; 44 Ca/n,p/ 44 K: 0.065+-0.003 mb. (T.G.)

  1. Types and rate of cataract development in mice irradiated at different ages

    International Nuclear Information System (INIS)

    Gajewski, A.K.; Majewska, K.; Slowikowska, M.G.; Chomiczewski, K.; Kulig, A.

    1977-01-01

    The effect of age on the development of radiation cataract has been investigated in an inbred A strain of mice and, as a result, the patterns of age dependence and senile mice cataract development were obtained. In general, the lenses of mice 1 to 3 days old were the most sensitive to radiation; the maximum resistance was noted in 5-day-old mice, and from this age up to 3 to 7 weeks of life there was a period of increasing sensitivity. In older animals the lens sensitivity tends to level off. The early stages of cataract occurred in all irradiated groups at a younger age than in the control group, but the late stages occurred in irradiated groups at the same age as the senile cataract occurred in the control group. Two types of cataract were observed. One was typical for young irradiated mice 1 to 5 days of age and the other was typical for all remaining irradiated groups and for a control group. Also, an attempt was made to correlate the obtained results with the cell kinetics in normal lens epithelium

  2. Positron annihilation measurements in high-energy alpha-irradiated n-type gallium arsenide

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Sandip; Mandal, Arunava; SenGupta, Asmita [Visva-Bharati, Department of Physics, Santiniketan, West Bengal (India); Roychowdhury, Anirban [UGC-DAE Consortium for Scientific Research, Kolkata Centre, Kolkata, West Bengal (India)

    2015-07-15

    Positron annihilation lifetime spectroscopy and Doppler broadening annihilation line-shape measurements have been carried out in 40-MeV alpha-irradiated n-type GaAs. After irradiation, the sample has been subjected to an isochronal annealing over temperature region of 25-800 C with an annealing time of 30 min at each set temperature. After each annealing, the positron measurements are taken at room temperature. Formation of radiation-induced defects and their recovery with annealing temperature are investigated. The lifetime spectra of the irradiated sample have been fitted with two lifetimes. The average positron lifetime τ{sub avg} = 244 ps at room temperature after irradiation indicates the presence of defects, and the value of τ{sub 2} (262 ps) at room temperature suggests that the probable defects are mono-vacancies. Two distinct annealing stages in τ{sub avg} at 400-600 C and at 650-800 C are observed. The variations in line-shape parameter (S) and defect-specific parameter (R) during annealing in the temperature region 25-800 C resemble the behaviour of τ{sub avg} indicating the migration of vacancies, formation of vacancy clusters and the disappearance of defects between 400 and 800 C. (orig.)

  3. Preparation, characterization and activity evaluation of p-n junction photocatalyst p-CaFe2O4/n-Ag3VO4 under visible light irradiation

    International Nuclear Information System (INIS)

    Chen Shifu; Zhao Wei; Liu Wei; Zhang Huaye; Yu Xiaoling; Chen Yinghao

    2009-01-01

    p-n junction photocatalyst p-CaFe 2 O 4 /n-Ag 3 VO 4 was prepared by ball milling Ag 3 VO 4 in H 2 O doped with p-type CaFe 2 O 4 . The structural and optical properties of the photocatalyst were characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and UV-vis diffuse reflection spectrum (DRS). The photocatalytic activity was evaluated by photocatalytic degradation of methylene blue (MB) under visible light irradiation. The results showed that the photocatalytic activity of the p-CaFe 2 O 4 /n-Ag 3 VO 4 was higher than that of Ag 3 VO 4 . When the amount of doped p-CaFe 2 O 4 was 2.0 wt.% and the p-CaFe 2 O 4 /n-Ag 3 VO 4 was ball milled for 12 h, the photocatalytic degradation efficiency was 85.4%. Effect of ball milling time on the photocatalytic activity of the photocatalyst was also investigated. The mechanisms of the increase in the photocatalytic activity were discussed by the p-n junction principle.

  4. Origin of the main deep electron trap in electron irradiated InP

    International Nuclear Information System (INIS)

    Sibille, A.

    1986-01-01

    The electrical activity and annealing behavior of the main electron trap in electron irradiated InP p + n junctions has been investigated. A very marked depth dependence of the annealing rate has been found. Moreover, this center apparently acts as if it were a deep donor, leading to an increase of carrier concentration on the n side. All these results are coherently interpreted with a model in terms of radiation defect D(P) (phosphorus interstitial or vacancy), residual shallow acceptor complexing, the final annealing resulting from a dissociation of the complex followed by a diffusion and either recapture or annihilation of D(P)

  5. Magnetic field evolution in dwarf and Magellanic-type galaxies

    Science.gov (United States)

    Siejkowski, H.; Soida, M.; Chyży, K. T.

    2018-03-01

    Aims: Low-mass galaxies radio observations show in many cases surprisingly high levels of magnetic field. The mass and kinematics of such objects do not favour the development of effective large-scale dynamo action. We attempted to check if the cosmic-ray-driven dynamo can be responsible for measured magnetization in this class of poorly investigated objects. We investigated how starburst events on the whole, as well as when part of the galactic disk, influence the magnetic field evolution. Methods: We created a model of a dwarf/Magellanic-type galaxy described by gravitational potential constituted from two components: the stars and the dark-matter halo. The model is evolved by solving a three-dimensional (3D) magnetohydrodynamic equation with an additional cosmic-ray component, which is approximated as a fluid. The turbulence is generated in the system via supernova explosions manifested by the injection of cosmic-rays. Results: The cosmic-ray-driven dynamo works efficiently enough to amplify the magnetic field even in low-mass dwarf/Magellanic-type galaxies. The e-folding times of magnetic energy growth are 0.50 and 0.25 Gyr for the slow (50 km s-1) and fast (100 km s-1) rotators, respectively. The amplification is being suppressed as the system reaches the equipartition level between kinetic, magnetic, and cosmic-ray energies. An episode of star formation burst amplifies the magnetic field but only for a short time while increased star formation activity holds. We find that a substantial amount of gas is expelled from the galactic disk, and that the starburst events increase the efficiency of this process.

  6. Effect of elevated postirradiation pH on the yield of double-strand breaks in DNA from irradiated bacterial cells

    International Nuclear Information System (INIS)

    Tilby, M.J.; Loverock, P.S.; Fielden, E.M.

    1984-01-01

    Exposure of DNA isolated from irradiated cells of Escherichia coli to a pH of 9.6 caused a marked increase in the yield of double-strand breaks (dsb). After incubation for 4 hr at 37 0 C and pH 9.6 the dsb yields were 95% and 71% higher than when incubation was at pH 7.0 for irradiation under oxic and anoxic conditions, respectively. This effect was not apparent when dsb were induced enzymatically and it was linearly related to radiation dose. After oxic irradiation, the increase in dsb at pH 9.6 was consistent with first-order kinetics over >2 half-lives (t/sub 1/2/ = 1.6 hr at 37 0 C). It is propsoed that the effects of elevated pH revealed the presence in intracellularly irradiated DNA of previously unidentified sites where both strands of the DNA were damaged as a result of single radiation events. The possible nature of the proposed sites and the relevance of these findings to the ''neutral'' elution technique are discussed

  7. Effect of gamma irradiation on Burkholderia thailandensis ( Burkholderia pseudomallei surrogate) survival under combinations of pH and NaCl

    Science.gov (United States)

    Yoon, Yohan; Kim, Jae-Hun; Byun, Myung-Woo; Choi, Kyoung-Hee; Lee, Ju-Woon

    2010-04-01

    This study evaluated the effect of gamma irradiation on Burkholderia thailandensis ( Burkholderia pseudomallei surrogate; potential bioterrorism agent) survival under different levels of NaCl and pH. B. thailandensis in Luria Bertani broth supplemented with NaCl (0-3%), and pH-adjusted to 4-7 was treated with gamma irradiation (0-0.5 kGy). Surviving cell counts of bacteria were then enumerated on tryptic soy agar. Data for the cell counts were also used to calculate D10 values (the dose required to reduce 1 log CFU/mL of B. thailandensis). Cell counts of B. thailandensis were decreased ( P<0.05) as irradiation dose increased, and no differences ( P≥0.05) in cell counts of the bacteria were observed among different levels of NaCl and pH. D10 values ranged from 0.04 to 0.07 kGy, regardless of NaCl and pH level. These results indicate that low doses of gamma irradiation should be a useful treatment in decreasing the potential bioterrorism bacteria, which may possibly infect humans through foods.

  8. Magnetization reversal of a type-II superconductor thin disk under the action of a constant magnetic field

    International Nuclear Information System (INIS)

    Koval'chuk, D.G.; Chornomorets', M.P.

    2010-01-01

    The applicability of relations obtained by Clem and Sanchez for the ac magnetic susceptibility of type-II superconductor thin films to the case where an additional constant magnetic field is applied perpendicularly to the film has been analyzed in the framework of the critical state model. The issues concerning the sample 'memory' and the influence of the magnetic field change prehistory on the current sample state have been discussed. It has been shown that the ac component of the magnetic moment and, hence, the amplitudes of ac magnetic susceptibility harmonics are established within one period of the ac magnetic field irrespective of the field prehistory.

  9. Bilateral irradiation of head and neck induces and enhanced expression of substance P in the parasympathetic innervation of the submandibular gland

    Energy Technology Data Exchange (ETDEWEB)

    Forsgren, S; Franzen, L; Funegard, U; Gustafsson, H; Henriksson, R [Umeaa Univ. (Sweden). Dept. of Oncology, Anatomy and Oto-laryngology

    1992-01-01

    Substance P and calcitonin gene-related peptide (CGRP) are present in nerve fibers innervating the submandibular gland. Radiotherapy of tumours in the head and neck region usually embraces the salivary glands in the irradiated field and consequently a dramatic decrease in salivary function is seen. In this study, the submandibular glands and ganglia of rats subjected to fractionated irradiation were examined by use of immunohistochemical techniques for demonstration of substance P and CGRP. Irradiation was given on five consecutive days with unilateral or bilateral irradiation techniques. Specimens of control and experimental animals were processed in parallel. A marked increase in the expression of substance P in the ganglionic cells-presumably parasympathetic-and in the number of fibers showing substance P-like immunoreactivity in association with acini and small ducts was seen in response to bilateral irradiation. No changes in the pattern of CGRP immunoreactivity occurred. In the trigeminal ganglion, which supplies the submandibular gland with the majority of the sensory substance P-and CGRP-containing nerve fibers, no changes in the expression of substance P or CGRP immunoreactivity were seen. The results suggest that bilateral irradiation leads to an increase in the synthesis of substance P-like substance in the parasympathetic ganglionic cells supplying the submandibular gland with secretory nerves, and can thus be an additional factor in explaining the altered secretory capacity of salivary glands. (author).

  10. Detection of irradiation induced modifications in foodstuff DNA using 32p post-labelling

    International Nuclear Information System (INIS)

    Hoey, B.M.; Swallow, A.J.; Margison, G.P.

    1991-01-01

    DNA post-labelling has been used successfully to detect damage to DNA caused by a range of damaging agents. The assay results in a fingerprint of changes induced in DNA which might, in principle, be useful as a test for the detection of the irradiation of foods. The authors present their DNA extraction and 32 p post-labelling methods from chicken or cooked prawn samples and their analysis method (High Performance liquid chromatography). It's hoped that these results could form the basis of a test to detect if foods have been irradiated

  11. P-type zinc oxide spinels: application to transparent conductors and spintronics

    International Nuclear Information System (INIS)

    Stoica, Maria; S Lo, Cynthia

    2014-01-01

    We report on the electronic and optical properties of two theoretically predicted stable spinel compounds of the form ZnB 2 O 4 , where B = Ni or Cu; neither compound has been previously synthesized, so we compare them to the previously studied p-type ZnCo 2 O 4 spinel. These new materials exhibit spin polarization, which is useful for spintronics applications, and broad conductivity maxima near the valence band edge that indicate good p-type dopability. We show that 3d electrons on the octahedrally coordinated Zn atom fall deep within the valence band and do not contribute significantly to the electronic structure near the band edge of the material, while the O 2p and tetrahedrally coordinated B 3d electrons hybridize broadly in the shallow valence states, resulting in increasing curvature (i.e., decreased electron effective mass) of valence bands near the band edge. In particular, ZnCu 2 O 4 exhibits high electrical conductivities in the p-doping region near the valence band edge that, at σ=2×10 4  S cm −1 , are twice the maximum found for ZnCo 2 O 4 , a previously synthesized compound in this class of materials. This material also exhibits ferromagnetism in all of its most stable structures, which makes it a good candidate for further study as a dilute magnetic semiconductor. (paper)

  12. Precipitation response of annealed type 316 stainless steel in HFIR irradiations at 550 to 6800C

    International Nuclear Information System (INIS)

    Maziasz, P.J.

    1978-01-01

    Precipitation in annealed type 316 stainless steel after HFIR irradiation at 550--680 0 C to fluences producing 2000--3300 at. ppM He and 30--47 dpa is changed relative to fast reactor or thermal aging exposure to similar temperatures and times. The phases observed after HFIR irradiation are the same as those observed after aging to temperatures 70--200 0 C higher or for much longer times. There is a similar temperature shift in addition to different phases observed for HFIR irradiation compared with EBR-II. The changes observed are coincident with including simultaneous helium production to high levels in the irradiation damage products of the material

  13. Rotor design of a novel self-start type permanent magnet synchronous motor

    OpenAIRE

    Egawa, T; Higuchi, Tsuyoshi; Yokoi, Yuichi; Abe, T; Miyamoto, Yasuhiro; Ohto, M

    2012-01-01

    Recently, permanent magnet type synchronous motor has been used widely for industry application. In the paper, we propose a novel self-start type permanent magnet synchronous motor with squirrel-cage and analyze the basic characteristics of the motor. We try to increase the efficiency by the rotor design with the finite element analysis.

  14. The precipitation response of 20%-cold-worked type 316 stainless steel to simulated fusion irradiation

    International Nuclear Information System (INIS)

    Maziasz, P.J.

    1979-01-01

    The precipitation response of 20%-cold-worked type 316 stainless steel has been examined after irradiation in HFIR at 380-600 0 C, after irradiation in EBR-II at 500 0 C, and after thermal aging at 600 to 750 0 C. Eta phase forms during exposure to all environments. It constitutes a major portion of the precipitation response, and is rich in Ni, Si and Mo relative to M 23 C 6 after thermal aging. It is not normally reported in 20%-cold-worked type 316 stainless steel. The eta, M 23 C 6 , Laves, sigma, and chi precipitate phases appear at similar temperatures after HFIR, EBR-II, or thermal exposure. There are, however, some differences in relative amounts, size, and distribution of phases among the various environments. Eta phase is the only carbide-type phase observed after irradiation in HFIR from 380-550 0 C. The large cavities associated with it at 380 0 C contribute significantly to swelling. Re-solution of fine M 23 C 6 , eta, and Laves particles and re-precipitation of massive particles of sigma, M 23 C 6 and chi are observed after recrystallization in HFIR. (orig.)

  15. Change of I-V characteristics of SiC diodes upon reactor irradiation; Modification des caracteristiques I-V de jonctions p-n au SiC du fait d'une irradiation dans un reacteur; Izmeneniya kharakteristik I-V vyrashchennogo v SiC perekhoda tipa p-n posle oblucheniya ego v reaktore; Modificaciones que sufren por irradiacion en un reactor las caracteristicas I-V de uniones p-n en SiC

    Energy Technology Data Exchange (ETDEWEB)

    Heerschap, M; De Coninck, R [Solid State Physics Dept., SCK-CEN, Mol (Belgium)

    1962-04-15

    In search for semiconductors, which can be used in high-flux reactors in order to measure flux distributions, we irradiated SiC p-n junctions in the Belgium BR-1 reactor. Two types of SiC-diodes of different origin have been irradiated. These junctions are grown in the Lely-furnace. The change in forward and reverse characteristics have been measured during and after irradiation up to temperatures of 150{sup o}C, while measurements up to a temperature of 500{sup o}C are in progress. It has been found that one type resists BR-1 neutrons up to an integrated flux of 10{sup 15} n/cm{sup 2}, while the other resists irradiation up to a flux of 10{sup 17} n/cm{sup 2}. The changes in characteristics are given as well as the result of some annealing experiments. (author) [French] En recherchant des semi-conducteurs pouvant servir a mesurer les distributions de flux dans les reacteurs a haut flux de neutrons, les auteurs ont irradie des jonctions p-n au SiC dans le reacteur belge BR-1. Deux types de diodes a SiC d'origines differentes ont ete ainsi irradies. Les jonctions en question sont preparees par etirage dans le four Lely. Les auteurs ont mesure les modifications subies par les caracteristiques I-V apres et pendant l'irradiation a des temperatures allant jusqu'a 150{sup o}C; ils poursuivent leurs mesures dans la gamme des temperatures allant de 150{sup o}C a 500{sup o}C. Us ont constate que l'un des types de diode a SiC resiste aux neutrons du reacteur BR-1 jusqu'a 10{sup 15} n/cm{sup 2}, tandis que l'autre type resiste a l'irradiation jusqu'a 10{sup 17} n/cm{sup 2}. Les auteurs indiquent les modifications subies par les caracteristiques, ainsi que le resultat de certaines experiences de recuit. (author) [Spanish] Los autores estan tratando de encontrar semiconductores con los que sea posible medir distribuciones de flujo en reactores de flujo elevado, y con este fin irradiaron uniones p-n del SiC en el reactor BR-1 de Belgica. Irradiaron dos tipos de diodos de SiC de

  16. Synthesis of p-type GaN nanowires.

    Science.gov (United States)

    Kim, Sung Wook; Park, Youn Ho; Kim, Ilsoo; Park, Tae-Eon; Kwon, Byoung Wook; Choi, Won Kook; Choi, Heon-Jin

    2013-09-21

    GaN has been utilized in optoelectronics for two decades. However, p-type doping still remains crucial for realization of high performance GaN optoelectronics. Though Mg has been used as a p-dopant, its efficiency is low due to the formation of Mg-H complexes and/or structural defects in the course of doping. As a potential alternative p-type dopant, Cu has been recognized as an acceptor impurity for GaN. Herein, we report the fabrication of Cu-doped GaN nanowires (Cu:GaN NWs) and their p-type characteristics. The NWs were grown vertically via a vapor-liquid-solid (VLS) mechanism using a Au/Ni catalyst. Electrical characterization using a nanowire-field effect transistor (NW-FET) showed that the NWs exhibited n-type characteristics. However, with further annealing, the NWs showed p-type characteristics. A homo-junction structure (consisting of annealed Cu:GaN NW/n-type GaN thin film) exhibited p-n junction characteristics. A hybrid organic light emitting diode (OLED) employing the annealed Cu:GaN NWs as a hole injection layer (HIL) also demonstrated current injected luminescence. These results suggest that Cu can be used as a p-type dopant for GaN NWs.

  17. Tornado type closed magnetic trap for an ECR source

    CERN Document Server

    Abramova, K B; Voronin, A V; Zorin, V G

    1999-01-01

    We propose to use a Tornado type closed magnetic trap for creation of a source of mul-ticharged ions with plasma heating by microwave radiation. Plasma loss in closed traps is deter-mined by diffusion across the magnetic field, which increases substantially plasma confinement time as compared to the classical mirror trap [1]. We propose to extract ions with the aid of additional coils which partially destroy the closed structure of the magnetic lines in the trap, but don not influence the total confinement time. This allows for producing a controlled plasma flux that depends on the magnetic field of the additional coil. The Tornado trap also possesses merits such as an opportunity to produce high magnetic fields up to 3 T, which makes possible heating and confinement of plasma with a high density of electrons; plasma stability to magneto-hydrodynamic perturbations because the magnetic field structure corresponds to the "min B" configuration; and relatively low costs. All estimates and calculations were carrie...

  18. Radio-thermoluminescence of p-InP crystals

    International Nuclear Information System (INIS)

    Aliyev, M.I.; Rashidova, Sh.Sh.; Guseynova, M.A.; Aliyev, I.M.

    2004-01-01

    Full text: A 3 B 5 compounds, including InP, are called forth the heighten interest in connection with their use in such devices as bipolar and field transistors with hetero junctions, solar cells, light emitting diodes, etc. It is known that under influence of high-level radiation (gamma quanta electron, etc. bombardment ) in semiconductors there are formed either local energetic defect states of torn bonds in the case of the crystal radiation with gamma quanta or local energy level tails of gap states at the expense of the point defect formation and that leads to the change of electrophysical and optical properties of A 3 B 5 compounds. In the paper, it is put forward results of experimental investigations of radio-thermoluminescence (RTL) features of gamma irradiated p-InP crystals in the range of 80 to 400 K. Samples doped with InP were fabricated by the Czochralski method. p-In crystals were irradiated with gamma quanta by the isotopic source, 60 Co, with the dose power of D=1.03 Gy/s at temperature of 77 K. Curves for RTL were obtained by a radio-thermo-luminograph, RTL-69, while the heating rate was 5 K/min. Presents the dependence of RTL versus temperature after each stage of radiation with doses of D=10 kGy and D=35 kGy. It is shown, that with increasing the radiation dose the intensity of luminescence decreases. It is also observed a shift of the maximum peak at 180 K towards lower temperatures by 10 degrees. The peak after irradiation with the large dose (D=35 kGy) is manifested at 170 K. The peak being emerged after irradiation with the dose of D=35 kGy at 300 K correspondents the H 3 (0.51 eV) level, which is the P In 0 hole trap. The decrease of the peak intensity after irradiation with the high dose is apparently connected with radiation anti-structural defects (ASD) of the donor type, In P . Thus, the irradiation by gamma quanta of InP crystals, doped with Zn results in the point defect formation of the structure, i.e. defects of the ASD

  19. Design of spoke type motor and magnetizer for improving efficiency based rare-earth-free permanent-magnet motor

    Science.gov (United States)

    Kim, Young Hyun; Cheon, Byung Chul; Lee, Jung Ho

    2018-05-01

    This study proposes criteria for both optimal-shape and magnetizer-system designs to be used for a high-output spoke-type motor. The study also examines methods of reducing high-cogging torque and torque ripple, to prevent noise and vibration. The optimal design of the stator and rotor can be enhanced using both a response surface method and finite element method. In addition, a magnetizer system is optimally designed for the magnetization of permanent magnets for use in the motor. Finally, this study verifies that the proposed motor can efficiently replace interior permanent magnet synchronous motor in many industries.

  20. Design of spoke type motor and magnetizer for improving efficiency based rare-earth-free permanent-magnet motor

    Directory of Open Access Journals (Sweden)

    Young Hyun Kim

    2018-05-01

    Full Text Available This study proposes criteria for both optimal-shape and magnetizer-system designs to be used for a high-output spoke-type motor. The study also examines methods of reducing high-cogging torque and torque ripple, to prevent noise and vibration. The optimal design of the stator and rotor can be enhanced using both a response surface method and finite element method. In addition, a magnetizer system is optimally designed for the magnetization of permanent magnets for use in the motor. Finally, this study verifies that the proposed motor can efficiently replace interior permanent magnet synchronous motor in many industries.

  1. Recovery Effect and Life Prolong Effect of Long Term Low-Dose Rate Irradiation on Type II Diabetes Model Mice

    International Nuclear Information System (INIS)

    Nomura, T.; Makino, N.; Oda, T.; Suzuki, I.; Sakai, K

    2004-01-01

    The effects of low-dose rate gamma-irradiation were investigated on model mice for type II diabetes mellitus, C57BL/KsJ-db/db. The mice develop the type II diabetes by 10 weeks of age due to obesity and are characterized by hyperinsulinemia. Female 10-week old mice, a group of 12 mice, were irradiated at 0.65 mGy/hr from 137-Cs (370 GBq). The urine glucose levels of all of the mice were strongly positive at the beginning of the irradiation. In the irradiated group, the decrease in the glucose level was observed in 3 mice. Such recovery from the diabetes was never observed in 12 mice of non-irradiated control group. There is no systematic difference in the change of body weight, food assumption, and amount of drinking water, between the irradiated group and the non-irradiated group or between the recovered mice and the non-recovered mice. The survival was better in the irradiated group: the surviving fraction at the age of 90 weeks was 75% in the irradiated group, while 40% in the non-irradiated. Marked difference was also observed in the appearance of the coat hair, skin, and tail; better condition was kept in the irradiated group. In the irradiated mice mortality was delayed and the healthy appearance was prolonged in the irradiated mice by about 20 ? 30 weeks compared with the non-irradiated mice. These results suggest that the low-dose irradiation modified the condition of the diabetic mice, which lead not only to the recovery of the diabetes, but also to the suppression of the aging process. (Author)

  2. Study of irradiation defects in bismuth by electric transport measurements

    International Nuclear Information System (INIS)

    Le Goff, M.

    1984-01-01

    Pure monocrystalline bismuth is irradiated near 4K by electrons of different energies. Irradiation effects are measured by galvanomagnetic properties at low temperature. Frenkel pairs created during irradiation have a strong effect on carrier mobilities. The data are quantitatively analyzed assuming a rigid band model. After irradiation with 1 MeV electrons, each Frankel pair created corresponds to a total charge of 0.14 electrons. This result obtained by magnetoresistance and Hall effect is confirmed by Shubnikov-de Haas experiments. There is a linear variation between the excess carrier density (p-n) and the Frenkel pair concentration. The more important step of annealing is observed around 40-50 K. This step is attributed to interstitial migration. Resistivity presents a minimum at low temperature after irradiation with electrons of energy over 1.3 MeV. This is explained by virtual bound levels near the Fermi level. The Kondo effect bound to magnetic defects is discussed [fr

  3. Theoretical study for ICRF sustained LHD type p-11B reactor

    International Nuclear Information System (INIS)

    Watanabe, Tsuguhiro

    2003-04-01

    This is a summary of the workshop on 'Theoretical Study for ICRF Sustained LHD Type p- 11 B Reactor' held in National Institute for Fusion Science (NIFS) on July 25, 2002. In the workshop, study of LHD type D- 3 He reactor is also reported. A review concerning the advanced nuclear fusion fuels is also attached. This review was reported at the workshop of last year. The development of the p- 11 B reactor research which uses the LHD magnetic field configuration has been briefly summarized in section 1. In section 2, an integrated report on advanced nuclear fusion fuels is given. Ignition conditions in a D- 3 He helical reactor are summarized in section 3. 0-dimensional particle and power balance equations are solved numerically assuming the ISS95 confinement law including a confinement factor (γ HH ). It is shown that high average beta plasma confinement, a large confinement factor (γ HH > 3) and the hot ion mode (T i /T e > 1.4) are necessary to achieve the ignition of the D- 3 He helical reactor. Characteristics of ICRF sustained p- 11 B reactor are analyzed in section 4. The nuclear fusion reaction rate is derived assuming a quasilinear plateau distribution function (QPDF) for protons, and an ignition condition of p- 11 B reactor is shown to be possible. The 3 of the presented papers are indexed individually. (J.P.N.)

  4. Ultraviolet-irradiated urocanic acid suppresses delayed-type hypersensitivity to herpes simplex virus in mice

    International Nuclear Information System (INIS)

    Ross, J.A.; Howie, S.E.; Norval, M.; Maingay, J.; Simpson, T.J.

    1986-01-01

    Ultraviolet radiation is known to induce a transient defect in epidermal antigen presentation which leads to the generation of antigen-specific suppression of the delayed-type hypersensitivity (DTH) response. The putative receptor in skin for the primary event in UV-suppression is urocanic acid (UCA) which may then interact locally, or systemically, with antigen presenting cells or initiate a cascade of events resulting in suppression. We present the first direct evidence that UCA, when irradiated with a dose (96 mJ/cm2) of UVB radiation known to suppress the DTH response to herpes simplex virus, type 1 (HSV-1) in mice, can induce suppression following epidermal application or s.c. injection of the irradiated substance. This suppression is transferable with nylon wool-passed spleen cells

  5. Formation of Ga2O3 by the oxidation of p-type GaN thin films

    Energy Technology Data Exchange (ETDEWEB)

    Pinnisch, Melanie; Reppin, Daniel; Stehr, Jan; Laufer, Andreas; Hofmann, Detlev M.; Meyer, Bruno K. [1. Physikalisches Institut, Justus-Liebig-University, Giessen (Germany)

    2010-07-01

    Both GaN and Ga{sub 2}O{sub 3} are wide band gap semiconductors with energies of 3.45 eV and 4.9 eV, respectively. While GaN can be achieved p- or n-type conducting by doping, Ga{sub 2}O{sub 3} is n-type or high resistive dependent on the presence of oxygen vacancies. We studied the conversion of p-type Mg doped GaN thin films to Ga{sub 2}O{sub 3} by thermal treatments in the temperature range from 600 C to 1200 C and in different atmospheres. Changes of the film properties were studied by means of X-ray diffraction, photo-electron spectroscopy and atomic force microscopy. Optical and magnetic resonance methods were used to investigate the evolution of the dopands and defects.

  6. Trapped magnetic field in a (NdFeB)–(MgB2) pair-type bulk magnet

    International Nuclear Information System (INIS)

    Aldica, Gheorghe; Burdusel, Mihail; Badica, Petre

    2014-01-01

    Highlights: • Dense MgB 2 discs were obtained by ex-situ Spark Plasma Sintering. • A NdFeB–MgB 2 pair-type bulk magnet was tested for different working conditions. • The polarity of the NdFeB permanent magnet influences macro flux jumps of MgB 2 . • Trapped field of the pair was 2.45 T (20 K) and 3.3 T (12 K). - Abstract: Superconducting bulk discs, S, of 20 mm in diameter and 3.5 or 3.3 mm thickness of MgB 2 (pristine or added with cubic BN, respectively) with density above 97% were prepared by Spark Plasma Sintering. Discs were combined in a pair-type sandwich-like arrangement with a permanent NdFeB axially magnetised magnet, PM (∼0.5 T). Measurement of the trapped field, B tr , with temperature, time, and the reduction rate of the applied magnetic field was performed using a Hall sensor positioned at the centre between the superconductor and the permanent magnet. It is shown that the permanent magnet with certain polarity favors higher trapped field of the superconductor owing to suppression of flux jumps specific for high density MgB 2 samples. The B tr of the PM–S pair was 2.45 T (20 K) and 3.3 T (12 K)

  7. Enhancement of structural and magnetic properties of M-type hexaferrite permanent magnet based on synthesis temperature

    Science.gov (United States)

    Anjum, Safia; Sehar, Fatima; Mustafa, Zeeshan; Awan, M. S.

    2018-01-01

    The main purpose of this research work is to develop the single domain magnetic particles of M-type barium hexaferrite (BaFe12O19) using oxide precursors employing conventional powder metallurgy technique. The phase formation and magnetic performance of the powders and magnets will be optimized by adjusting calcination and sintering temperatures. The synthesis of M-type barium hexaferrite was carried out in two sections. A series of four samples have been prepared by initial wet mixed powders calcined at different temperatures, i.e., 750, 850, 950 and 1050 °C. On the basis of structural analysis, the sample calcined at 950 °C has been selected and further divided into four parts to sintered them at 1100, 1150, 1200 and 1250 °C. The structural measurements depict the confirmation of M-type barium hexaferrite structure. SEM micrographs show the hexagonal-shaped grains. The abrupt decrease in coercivity for the sample sintered at 1250 °C has been seen which may be due to high sintering temperature, at which the particles have multi-domain properties.

  8. Ion, X-ray, UV and Neutron Microbeam Systems for Cell Irradiation.

    Science.gov (United States)

    Bigelow, A W; Randers-Pehrson, G; Garty, G; Geard, C R; Xu, Y; Harken, A D; Johnson, G W; Brenner, D J

    2010-08-08

    The array of microbeam cell-irradiation systems, available to users at the Radiological Research Accelerator Facility (RARAF), Center for Radiological Research, Columbia University, is expanding. The HVE 5MV Singletron particle accelerator at the facility provides particles to two focused ion microbeam lines: the sub-micron microbeam II and the permanent magnetic microbeam (PMM). Both the electrostatic quadrupole lenses on the microbeam II system and the magnetic quadrupole lenses on the PMM system are arranged as compound lenses consisting of two quadrupole triplets with "Russian" symmetry. Also, the RARAF accelerator is a source for a proton-induced x-ray microbeam (undergoing testing) and is projected to supply protons to a neutron microbeam based on the (7)Li(p, n)(7)Be nuclear reaction (under development). Leveraging from the multiphoton microscope technology integrated within the microbeam II endstation, a UV microspot irradiator - based on multiphoton excitation - is available for facility users. Highlights from radiation-biology demonstrations on single living mammalian cells are included in this review of microbeam systems for cell irradiation at RARAF.

  9. Manifestation of π-contacts in magnetic field dependence of I-V characteristics for proximity-type 2D Josephson junction array

    International Nuclear Information System (INIS)

    Rivera, V.A.G.; Sergeenkov, S.; Marega, E.; Araujo-Moreira, F.M.

    2009-01-01

    Results on the temperature and magnetic field dependence of current-voltage characteristics (CVC) are presented for SNS-type 2D ordered array of Nb-Cu 0.95 Al 0.05 -Nb junctions. The critical current I C (T,H) and the power exponent a(T,H)=1+Φ 0 I C (T,H)/2k B T of the nonlinear CVC law V=R[I-I C (T,H)] a(T,H) are found to have a maximum at non-zero value of applied magnetic field H p =225 Oe, which is attributed to manifestation of π-type Josephson contacts in our sample.

  10. Effects of laser acupoint irradiation on blood glucose and glycosylated hemoglobin in type 2 diabetes mellitus

    Science.gov (United States)

    Hui-Hui, Liu; Guo-Xin, Xiong; Li-Ping, Zhang

    2016-06-01

    To investigate the effects of semiconductor laser acupoint irradiation on blood glucose, glycosylated hemoglobin and physical fitness in type 2 diabetes mellitus, 44 cases of type 2 diabetic patients were randomly divided into a control group and a treatment group. All patients in both groups were given a drug treatment. The Hegu, Quchi and Zusanli acupoints of patients in the treatment group were then irradiated daily for 15 d with a 10 MW semiconductor laser. Before and after treatment, patients in both groups underwent a variety of tests and measurements: a two-hour postprandial blood glucose test; a glycosylated hemoglobin test and body mass index (BMI), waist-to-hip ratio (WHR) and body fat percentage (BFP) measurements. The data detected after treatment greatly decreased in the treatment group and was significantly different from that in the control group. It is shown that the acupoint irradiation with a semiconductor laser can improve two-hour postprandial blood glucose, glycosylated hemoglobin and some physical fitness measurements in type 2 diabetes mellitus patients.

  11. Comparison of invitro cytotoxic and genotoxic potential of glass ionomer cement type IX on human lymphocytes before and after electron beam irradiation

    International Nuclear Information System (INIS)

    Hegde, Mithra N.; Brijesh; Shetty, Shilpa S.; Hegde, Nidarsh D.; Suchetha Kumari; Sanjeev, Ganesh

    2013-01-01

    Glass ionomer cements are widely used in dentistry as an adhesive restorative materials. However, the results of cytotoxicity and genotoxicity studies using these materials are inconclusive in literature. The aim of this study was to examine the cytotoxic and genotoxic potential of glass ionomer cement type IX available commercially before and after irradiation. Glass ionomer cement type IX was obtained commercially. Samples were prepared as per the ISO standard size of 25x2x2 mm using polytetrafluoroethylene teflon mould and divided into two groups - non irradiated and irradiated groups. The samples in radiated category were exposed to 10 KGy of electron beam irradiation at Microtron Centre, Mangalore University, Mangalore, India. For hemolysis assay, the samples were immersed in phosphate buffer saline and incubated at 370℃ for 24 hrs, 7 days and 14 days. 200 μL of 24 hr material extract was mixed with human peripheral blood lymphocyte tested for comet assay by single cell DNA comet assay and apoptosis by DNA diffusion assay. Hemolytic activity of non irradiated Glass ionomer cement type IX after 24 hrs, 7 days and 14 days was 78.18±10.13, 32.57±12.28, 38.56±4.68 respectively whereas hemolytic activity of irradiated Glass ionomer cement type IX after 24 hrs, 7 days and 14 days was 58.90±2.28, 35.04±1.09 and 34.26±7.71 respectively. The irradiation of Glass ionomer cement type IX with 10 KGy dose of electron beam irradiation did not show significant increase in the frequency of DNA damage when compared to that of the nonirradiated group. Apoptotic index did not show much difference between non-irradiated and irradiated groups. Taken together, we conclude that some components of glass ionomer cements show both genotoxic and cytotoxic effects. (author)

  12. THE EFFECT OF A TWISTED MAGNETIC FIELD ON THE PERIOD RATIO P{sub 1}/P{sub 2} OF NONAXISYMMETRIC MAGNETOHYDRODYNAMIC WAVES

    Energy Technology Data Exchange (ETDEWEB)

    Karami, K. [Department of Physics, University of Kurdistan, Pasdaran Street, Sanandaj (Iran, Islamic Republic of); Bahari, K., E-mail: KKarami@uok.ac.ir, E-mail: K.Bahari@razi.ac.ir [Physics Department, Faculty of Science, Razi University, Kermanshah (Iran, Islamic Republic of)

    2012-10-01

    We consider nonaxisymmetric magnetohydrodynamic (MHD) modes in a zero-beta cylindrical compressible thin magnetic flux tube modeled as a twisted core surrounded by a magnetically twisted annulus, with both embedded in a straight ambient external field. The dispersion relation is derived and solved analytically and numerically to obtain the frequencies of the nonaxisymmetric MHD waves. The main result is that the twisted magnetic annulus does affect the period ratio P{sub 1}/P{sub 2} of the kink modes. For the kink modes, the magnetic twist in the annulus region can achieve deviations from P{sub 1}/P{sub 2} = 2 of the same order of magnitude as in the observations. Furthermore, the effect of the internal twist on the fluting modes is investigated.

  13. Expression of p53 and p21 in primary glioblastomas

    International Nuclear Information System (INIS)

    Gross, M.W.; Nashwan, K.; Engenhart-Cabillic, R.; Kraus, A.; Mennel, H.D.; Schlegel, J.

    2005-01-01

    Background and purpose: primary glioblastomas (GBMs) are highly radioresistant, and in contrast to secondary GBMs, they bear wild-type (wt) p53 protein, which is stabilized in a proportion of these tumors. Therefore, it was investigated in vivo whether p53 expression has prognostic value in patients undergoing radiochemotherapy. Additionally, the authors tried to identify, in vitro, subgroups of primary GBM with different susceptibilities to irradiation, on the basis of their p53 and p21 responses to ionizing radiation. Material and methods: tumor tissue samples from 31 patients suffering from primary GBM undergoing a combined radiochemotherapy with topotecan were investigated. The percentage of cells expressing p53 protein was determined immunohistochemically. Additionally, primary cultures from eleven primary GBMs were established and investigated. p53 and p21 expressions were evaluated before irradiation with 10 Gy and at 2 and 8 h after irradiation. p53 protein expression was measured by western analysis and p21 mRNA expression by reverse transcription-polymerase chain reaction (RT-PCR). Results: the percentage of p53-positive cells within the tumor specimens obtained from the 31 patients ranged from 0% to 28%, the median value being 4.3%. No significant correlation with disease-free survival or overall survival was found. In vitro, p53 protein was detected in seven of eleven cultures from primary GBM. After irradiation a decrease in p53 protein expression was seen in six of the seven p53-positive cultures. Half of the cultures (two of four) without basal p53 expression showed an increase in p53 expression after irradiation. Basal overexpression of p21 was detected in six of the eleven cultures; in four out of six irradiation led to a decrease in p21 expression. In all cell lines (five of eleven) initially showing absent p21 expression, irradiation induced p21 expression. Despite these responses, G1 arrest was not detectable in any of the GBM cultures

  14. Study of charge transport in silicon detectors: Non-irradiated and irradiated

    International Nuclear Information System (INIS)

    Leroy, C.; Roy, P.; Casse, G.; Glaser, M.; Grigoriev, E.; Lemeilleur, F.

    1999-01-01

    The electrical characteristics of silicon detectors (standard planar float zone and MESA detectors) as a function of the particle fluence can be extracted by the application of a model describing the transport of charge carriers generated in the detectors by ionizing particles. The current pulse response induced by α and β particles in non-irradiated detectors and detectors irradiated up to fluences PHI ∼ 3 · 10 14 particles/cm 2 is reproduced via this model: i) by adding a small n-type region 15 μm deep on the p + side for the detectors at fluences beyond the n to p-type inversion and ii) for the MESA detectors, by considering one additional dead layer of 14 μm (observed experimentally) on each side of the detector, and introducing a second (delayed) component to the current pulse response. For both types of detectors, the model gives mobilities decreasing linearily up to fluences of about 5·10 13 particles/cm 2 and converging, beyond, to saturation values of about 1050 cm 2 /Vs and 450 cm 2 /Vs for electrons and holes, respectively. At a fluence PHI ∼ 10 14 particles/cm 2 (corresponding to about ten years of operation at the CERN-LHC), charge collection deficits of about 14% for β particles, 25% for α particles incident on the front and 35% for α particles incident on the back of the detector are found for both type of detectors

  15. Piezoresistance in p-type silicon revisited

    DEFF Research Database (Denmark)

    Richter, Jacob; Pedersen, Jesper; Brandbyge, Mads

    2008-01-01

    We calculate the shear piezocoefficient pi44 in p-type Si with a 6×6 k·p Hamiltonian model using the Boltzmann transport equation in the relaxation-time approximation. Furthermore, we fabricate and characterize p-type silicon piezoresistors embedded in a (001) silicon substrate. We find...... to experiments. Finally, we present a fitting function of temperature and acceptor density to the 6×6 model that can be used to predict the piezoresistance effect in p-type silicon. ©2008 American Institute of Physics...... that the relaxation-time model needs to include all scattering mechanisms in order to obtain correct temperature and acceptor density dependencies. The k·p results are compared to results obtained using a recent tight-binding (TB) model. The magnitude of the pi44 piezocoefficient obtained from the TB model...

  16. Analysis of levitation characteristics of radial-type superconducting magnetic bearings; Rajiarugata chodendojikijikuju no fujotokusei kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Fukuyama, H.; Takizawa, T. [NSK Ltd., Kanagawa (Japan)

    1999-11-25

    In the design of a large-scale flywheel. load capacity and bearing constants (i.e. spring and damping constants) should be accurately calculated. In this report, a newly developed analysis method for radial-type superconducting magnetic bearings (SMBs) composed of several couples of magnet rings and magnetic material spacers is described. The analysis based both on electromagnetic FEM of the magnetic field and the 2-dimensional Bean model for analysis of the magnetization of type-2 superconductors. To obtain accurate magnetization hysteresis that reflects the complex magnetic fields, a superconductor is meshed into cells and then the electromagnetic force between the magnetic fields of magnetics and the magnetization of the superconductor are calculated. Recently, computer programs which can calculate the axial load capacity of radial-type SMBs have been developed. Furthermore, programs which can calculate bearing constants are close to being completed. Calculated results on axial load capacity showed good agreement with the experimental results. (author)

  17. Optimizing the field distribution of a Halbach type permanent magnet cylinder using the soft iron and superhard magnet

    Science.gov (United States)

    Xu, Xiaonong; Lu, Dingwei; Xu, Xibin; Yu, Yang; Gu, Min

    2018-01-01

    When a conventional Halbach type Hollow Cylindrical Permanent Magnet Array (HCPMA) is used to generate magnetic induction over the magnitude of coercivity μ0Hc, some detrimental parasitic magnetic phenomena, such as the demagnetization, magnetization reversal, and vortexes of magnetization, can appear in the interior of the magnets. We present a self-consistent quantitative analysis of the magnetization and magnetic induction distributions inside the magnetic array by considering the anisotropic and nonlinear magnetization functions of the materials consisting of the array. These numeric simulations reveal novel magnetization structures resulted from the self-field of array. We demonstrate that both the field uniformity and magnetic flux in the pole gap can be modulated by partially substituting the magnets of high energy products with the soft irons and the superhard magnets. We also show how the optimized substitution parameters can be obtained for a HCPMA achieving the best field uniformity or the maximum magnetic flux.

  18. 119Sn Moessbauer spectroscopy in the magnetically diluted Heusler-type systems

    International Nuclear Information System (INIS)

    Ruebenbauer, K.

    1981-01-01

    119 Sn Moessbauer investigations of the ferromagnetically diluted Nisub(2)Mnsub(x)Bsub(1-x)Sn(B=Ti, V) and Pdsub(2)Mnsub(x)Vsub(1-x)Sn Heusler-type systems have been performed and the results are reviewed and discussed. It has been found that distributions of the transferred hyperfine magnetic field as seen by a tin nucleus are very sensitive for a type of the local magnetic interaction in these simple ferromagnets, especially when studied versus the sample temperature. This sensitivity allows to reach some conclusions about the coupling mechanism between localised manganese magnetic moments. Namely, it is concluded that the interaction beyond the second neighbour shell is practically irrelevant for the magnetic ordering process. This very fact means that the free electron approach to the calculation of exchange integrals can not be applied for these particular systems. (Author)

  19. Coronal Magnetic Field Lines and Electrons Associated with Type III

    Indian Academy of Sciences (India)

    Coronal Magnetic Field Lines and Electrons Associated with Type III–V Radio Bursts in a Solar Flare ... velocities of the electron streams associated with the above two types of bursts indicate ... Journal of Astrophysics and Astronomy | News ...

  20. Response of thyroid follicular cells to gamma irradiation compared to proton irradiation: II. The role of connexin 32

    Science.gov (United States)

    Green, L. M.; Tran, D. T.; Murray, D. K.; Rightnar, S. S.; Todd, S.; Nelson, G. A.

    2002-01-01

    The objective of this study was to determine whether connexin 32-type gap junctions contribute to the "contact effect" in follicular thyrocytes and whether the response is influenced by radiation quality. Our previous studies demonstrated that early-passage follicular cultures of Fischer rat thyroid cells express functional connexin 32 gap junctions, with later-passage cultures expressing a truncated nonfunctional form of the protein. This model allowed us to assess the role of connexin 32 in radiation responsiveness without relying solely on chemical manipulation of gap junctions. The survival curves generated after gamma irradiation revealed that early-passage follicular cultures had significantly lower values of alpha (0.04 Gy(-1)) than later-passage cultures (0.11 Gy(-1)) (P 0.1, n = 9). This strongly suggests that the presence of functional connexin 32-type gap junctions was contributing to radiation resistance in gamma-irradiated thyroid follicles. Survival curves from proton-irradiated cultures had alpha values that were not significantly different whether cells expressed functional connexin 32 (0.10 Gy(-1)), did not express connexin 32 (0.09 Gy(-1)), or were down-regulated (early-passage plus heptanol, 0.09 Gy(-1); late-passage plus heptanol, 0.12 Gy(-1)) (P > 0.1, n = 19). Thus, for proton irradiation, the presence of connexin 32-type gap junctional channels did not influence their radiosensitivity. Collectively, the data support the following conclusions. (1) The lower alpha values from the gamma-ray survival curves of the early-passage cultures suggest greater repair efficiency and/or enhanced resistance to radiation-induced damage, coincident with the expression of connexin 32-type gap junctions. (2) The increased sensitivity of FRTL-5 cells to proton irradiation was independent of their ability to communicate through connexin 32 gap junctions. (3) The fact that the beta components of the survival curves from both gamma rays and proton beams were

  1. Effect of ultraviolet B irradiation on delayed-type hypersensitivity, cytotoxic T lymphocyte activity, and skin graft rejection

    International Nuclear Information System (INIS)

    Tamaki, K.; Iijima, M.

    1989-01-01

    The influence of ultraviolet B irradiation on the induction of delayed-type hypersensitivity reactions to alloantigens by epidermal cells (EC), on the generation of cytotoxic T lymphocyte activity to alloantigens, and on skin graft rejection was studied. After the skin was irradiated with UVB in vitro, EC were obtained. The EC were injected subcutaneously, and the DTH reaction was compared with that induced by non-UVB-irradiated EC. A reduction in the DTH reaction was observed (from 62% to 99.1%). CTL activity in these mice was assessed after in vitro stimulation. CTL activity in mice sensitized with UVB-irradiated EC was significantly reduced. Furthermore, mice sensitized with UVB-irradiated EC did not reject a subsequent skin allograft in an accelerated fashion, whereas mice sensitized with non-UVB-irradiated EC did. The mechanism(s) of these reactions and the clinical application of the UVB irradiation prior to grafting are discussed

  2. Axial magnetic field extraction type microwave ion source with a permanent magnet

    International Nuclear Information System (INIS)

    Ishikawa, Junzo; Takagi, Toshinori

    1984-01-01

    A new type of microwave ion source in which a permanent magnet generates an axially directed magnetic field needed for the electron cyclotron resonance was developed. The electron cyclotron resonance produces a high density plasma in the ion source. A mA-order ion beam can be extracted. Compared with usual microwave ion sources, this source has a distinguished feature in that the axially directed magnetic field is formed by use of a permanent magnet. Shape of magnetic force lines near the ion extraction aperture was carefully investigated. The extracted ion current as a function of the ion extraction voltage was measured. The experimental data are in good agreement with the theoretical line. The ion source can be heated up to 500 deg C, and extraction of the alkaline metal ions is possible. The extracted ion current for various elements are shown in the table. The current density normalized by the proton was 350-650 mA/cm 2 which was nearly equal to the upper limit of the extractable positive ion current density. The plasma density was estimated and was 2 - 3 x 10 12 cm -3 . The mass spectrum of a Cesium ion beam was obtained. A negligible amount of impurities was observed. The emittance diagram of the extracted ion beam was measured. The result shows that a low emittance and high brightness ion source is constructed. (Kato, T.)

  3. The UV-light and X-irradiation induced conversion of p-phenoxyphenol in aqueous solution at 250C

    International Nuclear Information System (INIS)

    Ehrl, A.

    1975-01-01

    UV-photolysis and X-radiolysis of p-phenoxyphenol was expected to yield products analogous to those of thyronine, after aromatic structures being equivalent. When exposed to UV-light, p-phenoxyphenol was found being selectively converted into phenylhydroquinone in consequence of intramolecular rearrangement. The reaction heat was estimated applying bond energies to the conversion and comparing the result with differences in the combustion heat of homologous compounds. After X-irradiation, phenylhydroquinone however was not present. Formation of the irradiation products phenol, hydroquinone, p-benzoquinone and pyrocatechol presumed breakage of substrate molecules in consequence of intermolecular interaction with transient water radiolysis species. (orig.) [de

  4. Identification of proteins that regulate radiation-induced apoptosis in murine tumors with wild type p53

    Energy Technology Data Exchange (ETDEWEB)

    Seong, Jinsil; Oh, Hae Jin; Kim, Jiyoung; An, Jeung Hee; Kim, Wonwoo [Dept. of Radiation Oncology, Yonsei Univ. Medical College, Seoul (Korea, Republic of)

    2007-09-15

    In this study, we investigated the molecular factors determining the induction of apoptosis by radiation. Two murine tumors syngeneic to C3H/HeJ mice were used: an ovarian carcinoma OCa-I, and a hepatocarcinoma HCa-I. Both have wild type p53, but display distinctly different radiosensitivity in terms of specific growth delay (12.7 d in OCa-I and 0.3 d in HCa-I) and tumor cure dose 50% (52.6 Gy in OCa-I and >80 Gy in HCa-I). Eight-mm tumors on the thighs of mice were irradiated with 25 Gy and tumor samples were collected at regular time intervals after irradiation. The peak levels of apoptosis were 16.1{+-}0.6% in OCa-I and 0.2{+-}0.0% in HCa-I at 4 h after radiation, and this time point was used for subsequent proteomics analysis. Protein spots were identified by peptide mass fingerprinting with a focus on those related to apoptosis. In OCa-I tumors, radiation increased the expression of cytochrome c oxidase and Bcl2/adenovirus E1B-interacting 2 (Nip 2) protein higher than 3-fold. However in HCa-I, these two proteins showed no significant change. The results suggest that radiosensitivity in tumors with wild type p53 is regulated by a complex mechanism. Furthermore, these proteins could be molecular targets for a novel therapeutic strategy involving the regulation of radiosensitivity. (author)

  5. Identification of proteins that regulate radiation-induced apoptosis in murine tumors with wild type p53

    International Nuclear Information System (INIS)

    Seong, Jinsil; Oh, Hae Jin; Kim, Jiyoung; An, Jeung Hee; Kim, Wonwoo

    2007-01-01

    In this study, we investigated the molecular factors determining the induction of apoptosis by radiation. Two murine tumors syngeneic to C3H/HeJ mice were used: an ovarian carcinoma OCa-I, and a hepatocarcinoma HCa-I. Both have wild type p53, but display distinctly different radiosensitivity in terms of specific growth delay (12.7 d in OCa-I and 0.3 d in HCa-I) and tumor cure dose 50% (52.6 Gy in OCa-I and >80 Gy in HCa-I). Eight-mm tumors on the thighs of mice were irradiated with 25 Gy and tumor samples were collected at regular time intervals after irradiation. The peak levels of apoptosis were 16.1±0.6% in OCa-I and 0.2±0.0% in HCa-I at 4 h after radiation, and this time point was used for subsequent proteomics analysis. Protein spots were identified by peptide mass fingerprinting with a focus on those related to apoptosis. In OCa-I tumors, radiation increased the expression of cytochrome c oxidase and Bcl2/adenovirus E1B-interacting 2 (Nip 2) protein higher than 3-fold. However in HCa-I, these two proteins showed no significant change. The results suggest that radiosensitivity in tumors with wild type p53 is regulated by a complex mechanism. Furthermore, these proteins could be molecular targets for a novel therapeutic strategy involving the regulation of radiosensitivity. (author)

  6. Preparation Of Phosphorus-32 (P-32) From Irradiated Target P2O5 For Therapeutic Purposes In Nuclear Medicine

    International Nuclear Information System (INIS)

    Nguyen Dang Khoa; Chu Van Khoa; Duong Van Dong

    2011-01-01

    Phosphorus-32 is produced using the nuclear reaction 31 P (n,γ) 32 P by irradiation of the phosphorus peroxide (P 2O 5) target. Phosphoric acid is prepared by the dissolution of irradiated target in 40 ml of boiling chloric acid 0.1 N. When the dissolution of phosphor peroxide is completed, the beaker is allowed to cool. 8 ml of 30% H 2 O 2 is added and refluxed for 3 h. Finally, the solution is filtered through a sintered glass filter, porosity G3 and passed into a column of cationic exchanger (Dowex-50 W-X4 preconditioned in hydrogen form) to remove metallic impurities. The effluent is collected as the stock solution. Radiochemical purity is determined by paper chromatography (radiochemical purity control) in the solvent system: Whatman No. 1 paper and the mixture of isopropyl alcohol : water : 50% trichloracetic acid : 25% NH 4 OH (75:15:10:0.3 v/v.) as a mobile phase, developing time ranged from 12 to 17 h. Radiochemical purity of phosphoric acid (H 3 32 PO 4 ) solution prepared by our method is obtained more than 99%. (author)

  7. P -type transparent conducting oxides

    International Nuclear Information System (INIS)

    Zhang, Kelvin H L; Xi, Kai; Blamire, Mark G; Egdell, Russell G

    2016-01-01

    Transparent conducting oxides constitute a unique class of materials combining properties of electrical conductivity and optical transparency in a single material. They are needed for a wide range of applications including solar cells, flat panel displays, touch screens, light emitting diodes and transparent electronics. Most of the commercially available TCOs are n -type, such as Sn doped In 2 O 3 , Al doped ZnO, and F doped SnO 2 . However, the development of efficient p -type TCOs remains an outstanding challenge. This challenge is thought to be due to the localized nature of the O 2 p derived valence band which leads to difficulty in introducing shallow acceptors and large hole effective masses. In 1997 Hosono and co-workers (1997 Nature 389 939) proposed the concept of ‘chemical modulation of the valence band’ to mitigate this problem using hybridization of O 2 p orbitals with close-shell Cu 3 d 10 orbitals. This work has sparked tremendous interest in designing p -TCO materials together with deep understanding the underlying materials physics. In this article, we will provide a comprehensive review on traditional and recently emergent p -TCOs, including Cu + -based delafossites, layered oxychalcogenides, nd 6 spinel oxides, Cr 3+ -based oxides (3 d 3 ) and post-transition metal oxides with lone pair state (ns 2 ). We will focus our discussions on the basic materials physics of these materials in terms of electronic structures, doping and defect properties for p -type conductivity and optical properties. Device applications based on p -TCOs for transparent p – n junctions will also be briefly discussed. (topical review)

  8. The CAD concept for stellarator-type magnetic systems

    International Nuclear Information System (INIS)

    Vorobyova, V.P.; Martynov, S.A.; Khazhmuradov, M.A.

    2002-01-01

    The paper describes the computer-aided design (CAD) concept for stellarator-type magnetic systems. Consideration is given to the main peculiarities, principles, and dialog organization and design stages of the CAD. The practical realization of the concept is illustrated by specific examples

  9. Electron and gamma-ray irradiated NTD Si p-n structures static and dynamic parameters trade-off

    International Nuclear Information System (INIS)

    Marchenko, I.G.; Zhdanovich, N.E.; Karas', V.I.

    2005-01-01

    The comparison of different radiation defects types influence on static and dynamic parameters trade-off of power diodes fabricated on neutron-transmutation doped silicon have been fulfilled. Various defects sets were introduced utilizing electron irradiation (E=6 MeV), gamma-ray Co 60 irradiation and electron irradiation and subsequent annealing at temperature 700 degrees centigrade. It is established that optimal trade-of between forward voltage drop and operation speed is achieved in case of electron irradiation and annealing. In this case recombination process is governed by defect with energy level near middle of forbidden gap (E c -0.53 eV). The results obtained indicate on possibility of using these defect recombination properties for speed control in production of power fast high-voltage devices on the base of neutron-transmutation doped silicon. (authors)

  10. Effect of irradiation on the pH for 11 commercial salad dressings near expiration date

    International Nuclear Information System (INIS)

    Sagretti, Juliana M.A.; Fabbri, Adriana D.T.; Hirashima, Fabiana K.; Nunes, Thaise C.F.; Rogovschi, Vladimir D.; Sabato, Susy F.

    2013-01-01

    The demand for salad dressings has evolved significantly in recent years and has become a frequent option in the meal. The pH values for salad dressings are low, precisely because they are emulsions acidified by adding ingredients, such as, acetic acid and / or citric acid and preservatives like benzoic acid and / or sorbic those provide an environment unfavorable to the growth of many microorganisms. However, the deterioration of such products occur as a result of growth of lactobacilli, bacilli, yeasts, once damaged, can present loss of taste and dark spots on the surface as an indication of yeast colony formation. Whereas, the positive effects of gamma irradiation on food, such as improved safety and stability of food products on shelves, the pH is a key factor for assessing not only the conservation, but also to the quality. The aim of this study was to reassess the effects of radiation on the pH of 9 varieties of commercial salad dressing after 6 months of storage, near the expiration of samples validity. The samples were acquired on the market of Sao Paulo and subjected to low doses of radiation at irradiator Multipurpose IPEN / CNEN-SP. The irradiated samples were compared to control. Statistical analyzes were performed using the program Graph Pad 5 and adopting a significance level of 5% (p <0.05). (author)

  11. Effect of irradiation on the pH for 11 commercial salad dressings near expiration date

    Energy Technology Data Exchange (ETDEWEB)

    Sagretti, Juliana M.A.; Fabbri, Adriana D.T.; Hirashima, Fabiana K.; Nunes, Thaise C.F.; Rogovschi, Vladimir D.; Sabato, Susy F., E-mail: jusagretti@uol.com.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    The demand for salad dressings has evolved significantly in recent years and has become a frequent option in the meal. The pH values for salad dressings are low, precisely because they are emulsions acidified by adding ingredients, such as, acetic acid and / or citric acid and preservatives like benzoic acid and / or sorbic those provide an environment unfavorable to the growth of many microorganisms. However, the deterioration of such products occur as a result of growth of lactobacilli, bacilli, yeasts, once damaged, can present loss of taste and dark spots on the surface as an indication of yeast colony formation. Whereas, the positive effects of gamma irradiation on food, such as improved safety and stability of food products on shelves, the pH is a key factor for assessing not only the conservation, but also to the quality. The aim of this study was to reassess the effects of radiation on the pH of 9 varieties of commercial salad dressing after 6 months of storage, near the expiration of samples validity. The samples were acquired on the market of Sao Paulo and subjected to low doses of radiation at irradiator Multipurpose IPEN / CNEN-SP. The irradiated samples were compared to control. Statistical analyzes were performed using the program Graph Pad 5 and adopting a significance level of 5% (p <0.05). (author)

  12. Divertor Heat Flux Reduction by Resonant Magnetic Perturbations in the LHD-Type Helical DEMO Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Yanagi, N.; Sagara, A.; Goto, T.; Masuzaki, S.; Miyazawa, J., E-mail: yanagi@lhd.nifs.ac.jp [National Institute for Fusion Science, Toki (Japan)

    2012-09-15

    Full text: The conceptual design studies of the LHD-type helical fusion DEMO reactor, FFHR-d1, are progressing steadfastly. The LHD-type heliotron magnetic configuration equipped with the built- in helical divertors has a potential to realize low divertor heat flux in spatial average. However, the toroidal asymmetry may give more than a couple of times higher peak heat flux at some locations, as has been experimentally observed in LHD and confirmed by magnetic field-line tracing. By providing radiation dispersion accompanied with a plasma detachment, the heat flux may decrease significantly though the compatibility with a good core plasma confinement is an important issue to be explored. Whereas the engineering difficulties for developing materials to be used under the neutron environment require even further decrease of the heat flux (even though the heliotron is a unique configuration that divertor plates be largely shielded from the direct irradiation of neutrons by breeder blankets). In this respect, we proposed, in the last IAEA FEC, a new strike point sweeping scheme using a set of auxiliary helical coils, termed helical divertor (HD) coils. The HD coils carrying a few percent of the current amplitude of the main helical coils sweep the divertor strike points without altering the core plasma. Though this scheme is effective in dispersing the heat flux in the poloidal direction, the toroidal asymmetry still remains. The AC operation may also give unforeseen engineering difficulties. We here propose that the peak heat flux be mitigated using RMP fields in steady-state. The magnetic field-lines are numerically traced in the vacuum configuration and their footprints coming to the divertor regions are counted. Their fraction plotted as a function of the toroidal angle indicates that the peak heat flux be mitigated to {approx} 20 MW per square meters at 3 GW fusion power generation without having radiation dispersion when an RMP field is applied. We note that the

  13. Performance of the ALIBAVA portable readout system with irradiated and non-irradiated microstrip silicon sensors

    International Nuclear Information System (INIS)

    Marco-Hernadez, R.

    2009-01-01

    A readout system for microstrip silicon sensors has been developed as a result of collaboration among the University of Liverpool, the CNM of Barcelona and the IFIC of Valencia. The name of this collaboration is ALIBAVA and it is integrated in the RD50 Collaboration. This system is able to measure the collected charge in one or two microstrip silicon sensors by reading out all the channels of the sensor(s), up to 256, as an analogue measurement. The system uses two Beetle chips to read out the detector(s). The Beetle chip is an analogue pipelined readout chip used in the LHCb experiment. The system can operate either with non-irradiated and irradiated sensors as well as with n-type and p-type microstrip silicon sensors. Heavily irradiated sensors will be used at the SLHC, so this system is being to research the performance of microstrip silicon sensors in conditions as similar as possible to the SLHC operating conditions. The system has two main parts: a hardware part and a software part. The hardware part acquires the sensor signals either from external trigger inputs, in case of a radioactive source setup is used, or from a synchronised trigger output generated by the system, if a laser setup is used. This acquired data is sent by USB to be stored in a PC for a further processing. The hardware is a dual board based system. The daughterboard is a small board intended for containing two Beetle readout chips as well as fan-ins and detector support to interface the sensors. The motherboard is intended to process the data, to control the whole hardware and to communicate with the software by USB. The software controls the system and processes the data acquired from the sensors in order to store it in an adequate format file. The main characteristics of the system will be described. Results of measurements acquired with n-type and p-type irradiated and non-irradiated detectors using both the laser and the radioactive source setup will be also presented and discussed

  14. Effect of low-dose gamma irradiation on enterotoxin-positive strains of Clostridium perfringens Type A

    International Nuclear Information System (INIS)

    Barnhart, H.M. Jr.

    1976-01-01

    The effect of low-dose gamma irradiation on selected enterotoxin producing strains of Clostridium perfringens Type A was studied. The radioresistance of three strains NCTC-8239, NCTC-10239 and NCTC-8798 in 0.1 percent peptone water, beef gravy and ground beef was determined for both vegetative cells and spores. D 10 values were approximately 30 Krad in 0.1 percent peptone water and 175 Krad in beef menstruums. D 10 values for spores were approximately 250 Krad in 0.1 percent peptone water and 335 Krad in beef. Low-level irradiation induced a 2 hr lag for cell recovery at 37 0 C following irradiation though this was strain dependent. Heat resistance of vegetative cells decreased following irradiation, although one strain was stimulated in growth response and unaltered in its heat resistance. Spore activation and germination were not affected by low-level irradiation. Spores were not significantly inactivated at this level. Irradiation had no effect on subsequent survival of vegetative cells stored at cold temperatures. Enterotoxin production by irradiated cultures was not affected by the irradiation treatment. A method for quantitating C. perfringens enterotoxin using crossed-immunoelectrophoresis was developed. It was found that this technique could detect at least .05 g of enterotoxin, could utilize crude enterotoxin preparations and was more sensitive than other methods based on biological activity

  15. High photocarrier mobility in ultrafast ion-irradiated In.sub.0.53./sub.Ga.sub.0.47./sub.As

    Czech Academy of Sciences Publication Activity Database

    Delagnes, J.C.; Mounaix, P.; Němec, Hynek; Fekete, Ladislav; Kadlec, Filip; Kužel, Petr; Martin, M.; Mangeney, J.

    2009-01-01

    Roč. 42, č. 19 (2009), 195103/1-195103/6 ISSN 0022-3727 R&D Projects: GA ČR(CZ) GP202/09/P099; GA AV ČR(CZ) IAA100100902 Institutional research plan: CEZ:AV0Z10100520 Keywords : InGaAs * photocarrier mobility * ultrafast photoconductivity terahertz * ion irradiation * terahertz * ion irradiation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.083, year: 2009

  16. Study about internal friction in deformed - and irradiated pure titanium

    International Nuclear Information System (INIS)

    Miyada, L.T.

    1979-01-01

    Internal friction and modulus are measured in pure Ti at low temperature using an inverted torsion-pendulum at about 1 Hz. The presence of four relaxation peaks P' sub(d)(-140 0 C), P sub(d)(-101 0 C), P' sub(α)(-75 0 C) and P sub(α)(-50 0 C) has been found, and effects of plastic deformation, heat treatment and neutron irradiation on these peaks are investigated in detail. Activation energies and frequency factors of P sub(d) and Pα peaks are consistent with the data in higher frequency range reproted by other workers. The P sub(d) and P' sub(d) peaks grow after deformation and tend to decay after annealing at high temperatures or after neutron irradiation. Both peaks are resonably interpreted in terms of dislocation relaxation mechanisms (Bordoni type) arising from thermally activated motion of dislocations in different slip planes of h.c.f. structure. Peierls stress of dislocations giving rise to each peak have calculated based on Seeger's theory, and found to be consistent with that of f.c.c. metals. On the other hand, P sub(α) and P' sub(α) peaks grow significantly at the expense of P sub(d) and P' sub(d) peaks after neutron irradiation in deformed samples. The behaviour of these peaks as a function of irradiation dose and annealing temperatures strongly indicated that they are due to relaxations resulting from dislocations-point defects interactions (Hasiguti type). It is tentatively suggested that P sub(α) and P' sub(α) peaks are related with interactions of dislocations with divacancies and single vacancies, respectively. Application of Schiller's model showed a consistent result with regard to the P' sub(α) peak experimentally observed. (Author) [pt

  17. E2F1 induces p19INK4d, a protein involved in the DNA damage response, following UV irradiation.

    Science.gov (United States)

    Carcagno, Abel L; Giono, Luciana E; Marazita, Mariela C; Castillo, Daniela S; Pregi, Nicolás; Cánepa, Eduardo T

    2012-07-01

    Central to the maintenance of genomic integrity is the cellular DNA damage response. Depending on the type of genotoxic stress and through the activation of multiple signaling cascades, it can lead to cell cycle arrest, DNA repair, senescence, and apoptosis. p19INK4d, a member of the INK4 family of CDK inhibitors, plays a dual role in the DNA damage response, inhibiting cell proliferation and promoting DNA repair. Consistently, p19INK4d has been reported to become upregulated in response to UV irradiation and a great variety of genotoxic agents. Here, this induction is shown to result from a transcriptional stimulatory mechanism that can occur at every phase of the cell cycle except during mitosis. Moreover, evidence is presented that demonstrates that E2F1 is involved in the induction of p19INK4d following UV treatment, as it is prevented by E2F1 protein ablation and DNA-binding inhibition. Specific inhibition of this regulation using triplex-forming oligonucleotides that target the E2F response elements present in the p19INK4d promoter also block p19INK4d upregulation and sensitize cells to DNA damage. These results constitute the first description of a mechanism for the induction of p19INK4d in response to UV irradiation and demonstrate the physiological relevance of this regulation following DNA damage.

  18. Preparation and characterization of natural polymers as stabilizer for magnetic nanoparticles by gamma irradiation

    International Nuclear Information System (INIS)

    Eid, M.

    2012-01-01

    A Highly stable and uniformly distributed magnetic nanoparticles have been obtained onto hydroxyethyl methacrylate (HEMA)-Agar- Fe 3 O 4 (HAF), and HEMA-Gelatin- Fe 3 O 4 (HGF) networks via gamma irradiation and loading technique. The swelling property of the prepared hydrogels in bidistilled water and different ph's was studied and the results showed that, the swelling percent of the plain hydrogel was found to be higher for all different compositions. The morphology and structure of the prepared hydrogels and dispersion of the magnetite nanoparticles in the hydrogel network were examined by Scanning electron microscopy (SEM) and Infrared spectroscopy (FT-IR). The particle size of the formed magnetite nanoparticles has been confirmed by Dynamic light scattering (DLS) and Transmission electron microscope (TEM), and it was found to be smaller in loading technique than irradiation technique. The HEMA-Gelatin-Fe 3 O 4 has higher particle size than HEMA-Agar-Fe 3 O 4 (HAF). Finally, the drug loading capacities of the magnetite nanoparticles and their releasing dependence on different ph were investigated with doxorubicin hydrochloride (DOX) as an anticancer drug model.

  19. Primary defect transformations in high-resistivity p-type silicon irradiated with electrons at cryogenic temperatures

    CERN Document Server

    Makarenko, L F; Korshunov, F P; Murin, L I; Moll, M

    2009-01-01

    It has been revealed that self-interstitials formed under low intensity electron irradiationin high resistivity p-type silicon can be retained frozen up to room temperature. Low thermal mobility of the self-interstitials suggests that Frenkelpair sinsilicon can be stable at temperatures of about or higher than 100K. A broad DLTS peak with activation energy of 0.14–0.17eV can be identified as related to Frenkel pairs. This peak anneals out at temperatures of 120 140K. Experimental evidences are presented that be coming more mobile under forwardcurrent injection the self-interstitials change their charge state to a less positive one.

  20. Influence of impurities on the evolution of vacancy-type defects in neutron-irradiated nickel

    International Nuclear Information System (INIS)

    Druzhkov, A.P.; Perminov, D.A.; Arbuzov, V.L.

    2012-01-01

    Highlights: ► We study, by means of PAS, the effects of purity on damage evolution in neutron-irradiated Ni at 330 K. ► Impurity carbon atoms in solution decrease the cascade efficiency during irradiation. ► C–V complexes are formed on the recovery stage III in impure Ni irradiated with 10 −4 dpa. ► The formation of V-loops and SFTs dominate on stage III with increasing dose level. ► The thermal stability of SFTs in impure Ni is similar to that in pure Ni. - Abstract: In order to investigate the effect of impurities on vacancy defect evolution in nickel, specimens with high (5N) and technical (3N) purity were neutron-irradiated at ∼330 K in the IVV-2M reactor (Russia) to fluencies in the range of 1 × 10 21 –1 × 10 23 n/m 2 (E > 0.1 MeV) corresponding to displacement dose levels in the range of about 0.0001–0.01 dpa and subsequently stepwise annealed to about 900 K. The specimens of Ni with different purities were characterized both in as-irradiated state as well as after post-irradiation annealing by positron annihilation spectroscopy. The formation of three-dimensional vacancy clusters (3D-VCs) in cascades was observed under neutron irradiation. The density and size of 3D-VCs depended not only on dose level, but also on purity. The population of 3D-VCs in the technical Ni is lower than that in the high-purity Ni. 3D-VCs collapse into secondary-type clusters (stacking fault tetrahedra (SFTs) and vacancy loops) during stepwise annealing at 350–450 K (stage III in Ni). The suppression of secondary cluster formation in 3N Ni is attributed to an effective vacancy interaction with impurity carbon atoms, which based on a relatively large vacancy–carbon atom binding energy (0.32–0.35 eV). The trapping of vacancies released at the collapse of 3D-VCs by the interstitial impurity atoms dominates at low irradiation dose level (10 −4 dpa). Thus, we found that carbon impurity atoms have strong effects both on the primary vacancy-type defect