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Sample records for pulsed endor studies

  1. ENDOR with band-selective shaped inversion pulses

    Science.gov (United States)

    Tait, Claudia E.; Stoll, Stefan

    2017-04-01

    Electron Nuclear DOuble Resonance (ENDOR) is based on the measurement of nuclear transition frequencies through detection of changes in the polarization of electron transitions. In Davies ENDOR, the initial polarization is generated by a selective microwave inversion pulse. The rectangular inversion pulses typically used are characterized by a relatively low selectivity, with full inversion achieved only for a limited number of spin packets with small resonance offsets. With the introduction of pulse shaping to EPR, the rectangular inversion pulses can be replaced with shaped pulses with increased selectivity. Band-selective inversion pulses are characterized by almost rectangular inversion profiles, leading to full inversion for spin packets with resonance offsets within the pulse excitation bandwidth and leaving spin packets outside the excitation bandwidth largely unaffected. Here, we explore the consequences of using different band-selective amplitude-modulated pulses designed for NMR as the inversion pulse in ENDOR. We find an increased sensitivity for small hyperfine couplings compared to rectangular pulses of the same bandwidth. In echo-detected Davies-type ENDOR, finite Fourier series inversion pulses combine the advantages of increased absolute ENDOR sensitivity of short rectangular inversion pulses and increased sensitivity for small hyperfine couplings of long rectangular inversion pulses. The use of pulses with an almost rectangular frequency-domain profile also allows for increased control of the hyperfine contrast selectivity. At X-band, acquisition of echo transients as a function of radiofrequency and appropriate selection of integration windows during data processing allows efficient separation of contributions from weakly and strongly coupled nuclei in overlapping ENDOR spectra within a single experiment.

  2. Detection of Anisotropic Hyperfine Components of Chemically Prepared Carotenoid Radical Cations:1D and 2D ESEEM and Pulsed ENDOR Study

    International Nuclear Information System (INIS)

    Konovalova, Tatyana A.; Dikanov, Sergei A.; Bowman, Michael K.; Kispert, Lowell D.

    2001-01-01

    Canthaxanthin and 8'-apo-B-caroten-8'-al radical cations chemically prepared on activated silica-alumina and in CH2CI2 solution containing A1C13 were studied by pulsed EPR and ENDOR spectroscopies. Both the 1D three-pulse ESEEM and the 2D HYSCORE spectra of the carotenoid-A1C13 mixtures exhibited the 27 A1 nuclei peak at 3.75 MHz. This indicates electron-transfer interactions between carotenoids and A1III ions resulting in the formation and stabilization of carotenoid radical cations. Davies ENDOR measurements of the canthaxanthin radical cation on silica-alumina determined the hyperfine couplings of B protons belonging to three different methyl groups with ahI=2.6 MHz, aH2=8.6MHz, and ah3 ca. 13 MHz. The principal components of the proton hyperfine tensors were obtained from HYSCORE spectra in A1C13 solutions and on the solid support. Identification of the protons was made on the basis of isotropic hyperfine couplings determined by RHF-INDO/SP molecular orbital calculations. In frozen A1C13 solution, the C(7, 7')Ha and C(14, 14')-Ha a protons were observed for Canthaxanthin and the C(8 or 14')-Ha, C(15')-Ha were observed for 8'-apo-B-caroten-8'-al. On the silica-alumina support, the C(10, 10')-Ha, C(11, 11')-Ha, and C(15,15')-Ha a protons were measured for Canthaxanthin and the C(12)-Ha and C(15')-Ha were measured for 8' apo-B-caroten-8'-al. Some protons with large isotropic couplings (> 10 MHz) determined from HYSCORE analysis could be assigned to B protons, but the principal components of their hyperfine tensors are much more anisotropic than those reported previously for B protons. We suggest that cis/trans isomerization of carotenoids on silica-alumina results in stabilization of di-cis isomers with large isotropic couplings for some a protons which are comparable to those of B protons

  3. H?, D? and HD adsorption upon the metal-organic framework [Cu?Zn?(btc)?]? studied by pulsed ENDOR and HYSCORE spectroscopy

    Science.gov (United States)

    Jee, Bettina; Hartmann, Martin; Pöppl, Andreas

    2013-10-01

    The adsorption of hydrogen has become interesting in terms of gas separation as well as safe and reversible storage of hydrogen as an energy carrier. In this regard, metal-organic framework compounds are potential candidates. The metal-organic framework [Cu?Zn?(btc)?]? as a partially Zn-substituted analogue of the well known compound HKUST-1 is well suited for studying adsorption geometries at cupric ions by electron paramagnetic resonance (EPR) methods due to the formation of few mixed Cu/Zn paddle wheel units with isolated S = 1/2 electron spins. The adsorption of hydrogen (H2) as well as the deuterium (D2) and HD molecules were investigated by continuous wave EPR and pulsed ENDOR and HYSCORE spectroscopy. The principal values of the proton and deuterium hyperfine coupling tensors ? and ? were determined by spectral simulations as well as of the deuterium nuclear quadrupole tensor ? for adsorbed HD and D2. The results show a side-on coordination of HD and D2 with identical Cu-H and Cu-D distances rCuX = 2.8 Å with the tensors ? and ? aligned parallel to the C4 symmetry axis of the paddle wheel unit. A thermodynamic non-equilibrium state with J = 1, mJ = ±1 is indicated by the experimental data with ? and ? averaged by rotation around C4.

  4. Some ENDOR studies of 3d transition metal ions in semiconductors

    International Nuclear Information System (INIS)

    Engelen, P.P.J.

    1980-01-01

    The author considers 3d transition metal ions substituted in covalent semiconducting crystals. The magnitude of the contact hyperfine field at the 59 Co nucleus in cobalt doped CdS is determined. The results of an ENDOR study of supertransferred hyperfine interactions with nearest neighbour Ga ions in Mn doped GaP are presented. (G.T.H.)

  5. Application of ENDOR-induced electron spin resonance to the study of point defects in solids

    International Nuclear Information System (INIS)

    Niklas, J.R.; Spaeth, J.M.

    1980-01-01

    The technique of ENDOR-induced ESR (EI-ESR) is applied to the investigation of several point defects in insulating crystals. It is shown that the lineshape of the EI-ESR spectrum depends on the ENDOR line used for the experiment. The EI-ESR technique allows the separation of overlapping ESR spectra in the presence of several defects. New applications are the selection of spin states and the determination of relative signs of spin-Hamiltonian parameters, the selection of centre orientations and the assignment of nuclei in complex ENDOR spectra, and the determination of quadrupole interactions which are not resolved in the ENDOR spectrum. (author)

  6. Solid state radiation chemistry of co-crystallized DNA base pairs studied with EPR and ENDOR

    International Nuclear Information System (INIS)

    Nelson, W.H.; Nimmala, S.; Hole, E.O.; Sagstuen, E.; Close, D.M.

    1995-01-01

    For a number of years, the authors' group has focused on identification of radicals formed from x-irradiation of DNA components by application of EPR and ENDOR spectroscopic techniques to samples in the form of single crystals. With single crystals as samples, it is possible to use the detailed packing and structural information available from x-ray or neutron diffraction reports. This report summarizes results from two crystal systems in which DNA bases are paired by hydrogen bonding. Extensive results are available from one of these, 1-methyl-thymine:9-methyladenine (MTMA), in which the base pairing is the Hoogsteen configuration. Although this configuration is different from that found by Watson-Crick in DNA, nonetheless the hydrogen bond between T(O4) and A(NH 2 ) is present. Although MTMA crystals have been studied previously, the objective was to apply the high-resolution technique of ENDOR to crystals irradiated and studied at temperatures of 10 K or lower in the effort to obtain direct evidence for specific proton transfers. The second system, from which the results are only preliminary, is 9-ethylguanine:1-methyl-5-fluorocytosine (GFC) in which the G:C bases pair is in the Watson Crick configuration. Both crystal systems are anhydrous, so the results include no possible effects from water interactions

  7. Wide band ENDOR spectrometer

    International Nuclear Information System (INIS)

    Mendonca Filho, C.

    1973-01-01

    The construction of an ENDOR spectrometer operating from 0,5 to 75 MHz within a single band, with ore Klystron and homodine detection, and no fundamental changes on the electron spin resonance spectrometer was described. The ENDOR signal can be detected both by amplitude modulation of the frequency field, or direct detection of the ESR output, which is taken to a signal analyser. The signal-to-noise ratio is raised by averaging rather than filtering avoiding the use of long time constants, providing natural line widths. The experimental apparatus and the spectra obtained are described. A discussion, relating the ENDOR line amplitudes with the experimental conditions is done and ENDOR mechanism, in which there is a relevant presence of cross relaxation is proposed

  8. Electron spin resonance and E.N.D.O.R. double resonance study of free radicals produced by gamma irradiation of imidazole single crystals

    International Nuclear Information System (INIS)

    Lamotte, B.

    1970-01-01

    Gamma irradiation of imidazole single crystals at 300 deg. K gives two radicals. Identification and detailed studies of their electronic and geometric structure have been made by ESR and ENDOR techniques. A study of the hydrogen bonded protons hyperfine tensor is made and let us conclude to the inexistence of movement and tunneling of these protons. The principal low temperature radical, produced by gamma irradiation at 77 deg. K has been also studied by ESR and a model has been proposed. (author) [fr

  9. Electronic Structure of ZnO Quantum Dots studied by High-frequency EPR, ESE, ENDOR and ODMR Spectroscopy

    NARCIS (Netherlands)

    Baranov, P.G.; Romanov, N.G.; Bundakova, A.P.; de Mello-Donega, Celso; Schmidt, J.

    2016-01-01

    High-frequency electron paramagnetic resonance (EPR), electron spin echo (ESE), electron-nuclear double resonance (ENDOR) and optically detected magnetic resonance (ODMR) were applied for the investigation of the electronic properties of ZnO colloidal quantum dots (QDs) which consist of a ZnO

  10. Effects of ionizing radiation in cocrystals of DNA model compounds: ESR-ENDOR studies of X-irradiated imidazole:barbital and adenosine:5-bromouracil

    International Nuclear Information System (INIS)

    Kar, L.

    1982-01-01

    Electron spin resonance (ESR) and electron nuclear double resonance (ENDOR) techniques have been used to study radiation induced damage in cocrystalline complexes X-irradiated at 12 K. The study addresses the following questions: (1) whether radiation induced damage is stabilized preferentially on one of the components of the cocrystalline system; and (2) whether charge transfer occurs between purine and pyrimidine bases in hydrogen bonded or stacked configurations. The cocrystals used in this study are imidazole:5,5-diethylbarbituric acid (barbital) and adenosine:5-bromouracil (AR:BU). Results indicate that (1) preferential stability of radiation damage may be observed in a cocrystal even in the absence of stacking interactions; (2) in the presence of purine:pyrimidine stacking electron transfer may occur, but hole transfer is not likely to be the mechanism of redistribution of radiation damage in cocrystalline systems. The radiation chemistry of AR:BU is used as a model to predict the effects of ionizing radiation on DNA

  11. Electron spin resonance and E.N.D.O.R. double resonance study of free radicals produced by gamma irradiation of imidazole single crystals; Etude par resonance paramagnetique electronique et double resonance E.N.D.O.R. des radicaux libres crees par irradiation gamma de monocristaux d'imidazole

    Energy Technology Data Exchange (ETDEWEB)

    Lamotte, B [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1970-07-01

    Gamma irradiation of imidazole single crystals at 300 deg. K gives two radicals. Identification and detailed studies of their electronic and geometric structure have been made by ESR and ENDOR techniques. A study of the hydrogen bonded protons hyperfine tensor is made and let us conclude to the inexistence of movement and tunneling of these protons. The principal low temperature radical, produced by gamma irradiation at 77 deg. K has been also studied by ESR and a model has been proposed. (author) [French] L'irradiation gamma de monocristaux d'imidazole a 300 deg. K conduit a deux radicaux dont l'identification et l'etude detaillee des structures electroniques et geometriques ont ete obtenues par la resonance paramagnetique electronique (RPE) et la double resonance ENDOR. En particulier l'examen des protons de la liaison hydrogene permet de conclure, pour ceux-ci, a l'inexistence de tout mouvement par effet tunnel. De plus, l'analyse des spectres de RPE du radical principal cree par irradiation gamma de l'imidazole a 77 deg. K nous a permis de proposer un modele pour ce radical. (auteur)

  12. A theoretical interpretation of EPR and ENDOR

    International Nuclear Information System (INIS)

    Matos, M.O.M. de.

    1975-08-01

    To interpret the EPR and ENDOR results of the U 2 center in SrF 2 , two wavefunctions are proposed to describe the unpaired electron of the defect. Use is made of two different models in order to obtain the wavefunctions: the Heitler-London and that of molecular orbitals models. The Pauli repulsion (overlap of wavefunctions) is discussed as well as covalency mechanisms and their influence in the calculation of the hyperfine constants due to magnetic interaction of the unpaired electron and the magnetic nucleus of the cristal. A small amount of covalency between the ground state of the interstitial Hydrogen atom and the 2p shell of the F - ions of the first cristaline shell is introduced fenomenologically in the molecular orbitals model. Both methods are discussed by comparing the theoretical calculations of the hyperfine constants with the measured experimental values obtained with the EPR and ENDOR techniques. (Author) [pt

  13. ENDOR investigations on heat treatment centers in oxygen rich Si

    International Nuclear Information System (INIS)

    Michel, J.; Meilwes, N.; Spaeth, J.M.

    1989-01-01

    Previous ENDOR results on NL8 centers (thermal donors TD) in Czochralski (Cz) Si and 17 O diffused float zone (FZ) Si are summarised. Comparison of ENDOR spectra of NL8 centers in B and Al doped Si shows that no dopant impurity is involved in the TD + structure while Al is incorporated in the NL10 defects in Al-doped Si. No 10,11 B - ENDOR is found for NL10 in B doped Si. It is concluded that NL10 is not related to NL8 and that NL10 is not even a unique defect. (author) 6 refs., 4 figs., 1 tab

  14. Natural and induced endoreic hydrological conditions in the Alta Murgia karstic region (Apulia, Southern Italy)

    Science.gov (United States)

    Canora, F.; Fidelibus, M. D.; Spilotro, G.

    2009-04-01

    A study aimed at understanding the hydrological processes in karst areas related to the presence of natural and artificial endoreic basins and their modification due to land use change, as well as the influence of above factors on the infiltration rate has been carried out in the Alta Murgia region (Apulia, Southern Italy). The region is a Cretaceous limestone plateau of the Apulian platform, characterized by a mature karstic landscape: due to its elevation, climatic conditions and lithology, the plateau constitutes the main recharge area of the Murgia aquifer. The typical karst topography is essentially related to the subterranean drainage (sinkholes, caves, conduit): surface and subsurface karst geomorphology is strictly interrelated with hydrology. The morphological features of the karstic plateau are defined by the high density of surface karstic forms (mainly dolines), the presence of exposed karst and karren fields, as well as by the extensive outcrop of fractured rocks. Karst surface shows, on the bottom of the morpho-structural depressions called "lame", natural distribution of modest deposits of "terra rossa" and regolith. The "lame" work as streams during and after intense rainfall events, often outlining a primordial ephemeral hydrographical network, frequently convergent towards dolines, poljes or endoreic basins. Alta Murgia shows many natural endoreic basin conditions in a quite flat morphology. In this environment, when intense rainfall events cover large areas and rainfall intensity exceeds the infiltration capacity of soils and/or sinkholes, significant runoff amounts are produced and stored in the basins causing floods. Most of the natural endoreic basins are small and independent: while the majority of them continue functioning as endoreic even in presence of extreme events of high return time, others (quasi-endoreic), under the same circumstances can start contributing to other basins, due to exceeding their water storage capability. This way

  15. ENDOR-Induced EPR of Disordered Systems: Application to X-Irradiated Alanine.

    Science.gov (United States)

    Kusakovskij, Jevgenij; Maes, Kwinten; Callens, Freddy; Vrielinck, Henk

    2018-02-15

    The electron paramagnetic resonance (EPR) spectra of radiation-induced radicals in organic solids are generally composed of multiple components that largely overlap due to their similar weak g anisotropy and a large number of hyperfine (HF) interactions. Such properties make these systems difficult to study using standard cw EPR spectroscopy even in single crystals. Electron-nuclear double-resonance (ENDOR) spectroscopy is a powerful and widely used complementary technique. In particular, ENDOR-induced EPR (EIE) experiments are useful for separating the overlapping contributions. In the present work, these techniques were employed to study the EPR spectrum of stable radicals in X-irradiated alanine, which is widely used in dosimetric applications. The principal values of all major proton HF interactions of the dominant radicals were determined by analyzing the magnetic field dependence of the ENDOR spectrum at 50 K, where the rotation of methyl groups is frozen. Accurate simulations of the EPR spectrum were performed after the major components were separated using an EIE analysis. As a result, new evidence in favor of the model of the second dominant radical was obtained.

  16. Strong resistance of Arabidopsis thaliana and Raphanus sativus seeds for ionizing radiation as studied by ESR, ENDOR, ESE spectroscopy and germination measurement: Effect of long-lived and super-long-lived radicals

    Energy Technology Data Exchange (ETDEWEB)

    Kumagai, Jun E-mail: kumagai@apchem.nagoya-u.ac.jp; Katoh, Hiromi; Kumada, Takayuki; Tanaka, Atsushi; Tano, Shigemitsu; Miyazaki, Tetsuo

    2000-01-01

    Resistance of seeds for ionizing radiation effects on Arabidopsis thaliana and Raphanus sativus seeds were investigated by ESR, ENDOR, ESE spectroscopy and germination measurement. Two types of free radicals, such as long-lived (LL) and super-long-lived (SL) radicals, were produced by the {gamma}-irradiation in the seeds. More than 90% of the 1 kGy-irradiated-seeds can germinate probably by decreasing the LL radicals by absorbing water. 10 kGy-irradiated-seeds cannot germinate at all probably due to the existence of significant amounts of the SL radicals even after absorbing water. (author)

  17. Fingerprints of single nuclear spin energy levels using STM - ENDOR.

    Science.gov (United States)

    Manassen, Yishay; Averbukh, Michael; Jbara, Moamen; Siebenhofer, Bernhard; Shnirman, Alexander; Horovitz, Baruch

    2018-04-01

    We performed STM-ENDOR experiments where the intensity of one of the hyperfine components detected in ESR-STM is recorded while an rf power is irradiated into the tunneling junction and its frequency is swept. When the latter frequency is near a nuclear transition a dip in ESR-STM signal is observed. This experiment was performed in three different systems: near surface SiC vacancies where the electron spin is coupled to a next nearest neighbor 29 Si nucleus; Cu deposited on Si(111)7x7 surface, where the unpaired electron of the Cu atom is coupled to the Cu nucleus ( 63 Cu, 65 Cu) and on Tempo molecules adsorbed on Au(111), where the unpaired electron is coupled to a Nitrogen nucleus ( 14 N). While some of the hyperfine values are unresolved in the ESR-STM data due to linewidth we find that they are accurately determined in the STM-ENDOR data including those from remote nuclei, which are not detected in the ESR-STM spectrum. Furthermore, STM-ENDOR can measure single nuclear Zeeman frequencies, distinguish between isotopes through their different nuclear magnetic moments and detect quadrupole spectra. We also develop and solve a Bloch type equation for the coupled electron-nuclear system that facilitates interpretation of the data. The improved spectral resolution of STM - ENDOR opens many possibilities for nanometric scale chemical analysis. Copyright © 2018 Elsevier Inc. All rights reserved.

  18. EPR dating CO2- sites in tooth enamel apatites by ENDOR and triple resonance

    International Nuclear Information System (INIS)

    Vugman, N.V.; Rigby, S.E.J.

    1995-01-01

    In this work we combine electron paramagnetic resonance (EPR), high-resolution electron nucleus double resonance (ENDOR) and general triple resonance (GTR) spectroscopies, to study the local environment of the CO 2 - groups created by ionizing radiation in fossil tooth enamel. We demonstrate that the CO 2 - groups occupy slightly modified phosphate sites in the hydroxyapatite lattice. In quaternary shark enamel we found these groups to be interacting with water molecules in the apatite channels. The absence of water molecules as first neighbours in mammalian samples indicate, however, that these molecules are not significantly responsible for the stabilization of CO 2 - dating centers in enamel. (author)

  19. ENDOR-investigations in the environment of the ferroelectric phase transition temperature of γ-irradiated TSCC

    International Nuclear Information System (INIS)

    Welter, M.

    1983-01-01

    The structure of the CH 3 NHCH 2 COOH radical in the paraelectric phase and during the transition into the ferroelectric phase has been determined by means of ENDOR measurements. The carboxyl group of the radical is a sensitive probe for the study of crystal field changes. Structural differences of the radical between the paraelectric and the ferroelectric phase were attributed to structural changes within the nearest environment

  20. A Study of New Pulse Auscultation System

    Directory of Open Access Journals (Sweden)

    Ying-Yun Chen

    2015-04-01

    Full Text Available This study presents a new type of pulse auscultation system, which uses a condenser microphone to measure pulse sound waves on the wrist, captures the microphone signal for filtering, amplifies the useful signal and outputs it to an oscilloscope in analog form for waveform display and storage and delivers it to a computer to perform a Fast Fourier Transform (FFT and convert the pulse sound waveform into a heartbeat frequency. Furthermore, it also uses an audio signal amplifier to deliver the pulse sound by speaker. The study observed the principles of Traditional Chinese Medicine’s pulsing techniques, where pulse signals at places called “cun”, “guan” and “chi” of the left hand were measured during lifting (100 g, searching (125 g and pressing (150 g actions. Because the system collects the vibration sound caused by the pulse, the sensor itself is not affected by the applied pressure, unlike current pulse piezoelectric sensing instruments, therefore, under any kind of pulsing pressure, it displays pulse changes and waveforms with the same accuracy. We provide an acquired pulse and waveform signal suitable for Chinese Medicine practitioners’ objective pulse diagnosis, thus providing a scientific basis for this Traditional Chinese Medicine practice. This study also presents a novel circuit design using an active filtering method. An operational amplifier with its differential features eliminates the interference from external signals, including the instant high-frequency noise. In addition, the system has the advantages of simple circuitry, cheap cost and high precision.

  1. A study of new pulse auscultation system.

    Science.gov (United States)

    Chen, Ying-Yun; Chang, Rong-Seng

    2015-04-14

    This study presents a new type of pulse auscultation system, which uses a condenser microphone to measure pulse sound waves on the wrist, captures the microphone signal for filtering, amplifies the useful signal and outputs it to an oscilloscope in analog form for waveform display and storage and delivers it to a computer to perform a Fast Fourier Transform (FFT) and convert the pulse sound waveform into a heartbeat frequency. Furthermore, it also uses an audio signal amplifier to deliver the pulse sound by speaker. The study observed the principles of Traditional Chinese Medicine's pulsing techniques, where pulse signals at places called "cun", "guan" and "chi" of the left hand were measured during lifting (100 g), searching (125 g) and pressing (150 g) actions. Because the system collects the vibration sound caused by the pulse, the sensor itself is not affected by the applied pressure, unlike current pulse piezoelectric sensing instruments, therefore, under any kind of pulsing pressure, it displays pulse changes and waveforms with the same accuracy. We provide an acquired pulse and waveform signal suitable for Chinese Medicine practitioners' objective pulse diagnosis, thus providing a scientific basis for this Traditional Chinese Medicine practice. This study also presents a novel circuit design using an active filtering method. An operational amplifier with its differential features eliminates the interference from external signals, including the instant high-frequency noise. In addition, the system has the advantages of simple circuitry, cheap cost and high precision.

  2. Electron spin resonance (ESR), electron nuclear double resonance (ENDOR) and general triple resonance of irradiated biocarbonates

    International Nuclear Information System (INIS)

    Schramm, D.U.; Rossi, A.M.

    1996-01-01

    Several irradiated bicarbonates were studied by magnetic resonance techniques. Seven paramagnetic species, attributed to CO 2 - , SO 2 - and SO 3 - were identified. Comparison between radiation induced defects in bioaragonites and aragonite single-crystals show that isotropic and orthorhombic CO 2 - centers with broad line spectra are not produced in the latter samples. Vibrational and rotational properties of isotropic CO 2 - centers were studied from low temperature Q-band spectras. Vibrational frequency is determined from the 13 CO 2 - hyperfine spectrum and yielded ν 1.54 x 10 13 s -1 . The correlation time for isotropic CO 2 - , τc) = 1.2 x 10 -11 s (T = 300 K0, is typical of radicals rotating in liquids. ENDOR and General Triple spectroscopy show that orthorhombic CO 2 - centres are surrounded by water molecules located in the second nearest CO 2 2- sites at 5.14, 5.35 and 6.02 A. Water molecules replacing carbonates or as liquid inclusion of growth solution in local crystal imperfections may be responsible for the variety of orthorhombic and isotropic CO 2 - species, respectively. (author)

  3. Annular pulse column development studies

    International Nuclear Information System (INIS)

    Benedict, G.E.

    1980-01-01

    The capacity of critically safe cylindrical pulse columns limits the size of nuclear fuel solvent extraction plants because of the limited cross-sectional area of plutonium, U-235, or U-233 processing columns. Thus, there is a need to increase the cross-sectional area of these columns. This can be accomplished through the use of a column having an annular cross section. The preliminary testing of a pilot-plant-scale annular column has been completed and is reported herein. The column is made from 152.4-mm (6-in.) glass pipe sections with an 89-mm (3.5-in.) o.d. internal tube, giving an annular width of 32-mm (1.25-in.). Louver plates are used to swirl the column contents to prevent channeling of the phases. The data from this testing indicate that this approach can successfully provide larger-cross-section critically safe pulse columns. While the capacity is only 70% of that of a cylindrical column of similar cross section, the efficiency is almost identical to that of a cylindrical column. No evidence was seen of any non-uniform pulsing action from one side of the column to the other

  4. ESR-ENDOR study of x-irradiated single crystals of α.D.glucopyranose and α-methyl.D.glucopyranoside; environmental effects upon radiation and free radical chemistry in carbohydrate model systems

    International Nuclear Information System (INIS)

    Madden, K.P.

    1980-01-01

    Single crystals of x-irradiated α-D-glucopyranose (αGlu) and α-methyl-D-glucopyranoside (αMeGlu) were studied using electron spin resonance and electron nuclear double resonance spectroscopy, to determine products and reaction mechanisms in carbohydrate radiation and free-radical chemistry. Four free-radical products were identified in αMeGlu single crystals irradiated and studied at 77K. Irradiation and observation at 12K produced yet another species. Four free radicals were identified in αGlu single crystals irradiated and observed at 12K and 77K. Free radical reaction in αGlu and αMeGlu were induced by slowly warming crystals irradiated at 77K until conversion occurred. Environmental influences upon these free-radical reaction mechanisms are discussed. The results from previous work on irradiated aqueous glasses of αGlu is briefly reviewed, and compared to those obtained from the single crystal system

  5. ENDOR/ESR of Mn atoms and MnH molecules in solid argon

    Science.gov (United States)

    van Zee, R. J.; Garland, D. A.; Weltner, W., Jr.

    1986-09-01

    Mn atoms and MnH molecules, the latter formed by reaction between metal and hydrogen atoms, were trapped in solid argon and their ESR/ENDOR spectra measured at 4 K. At each pumping magnetic field two ENDOR lines were observed for 55Mn(I=5/2) atoms, corresponding to hyperfine transitions within the MS =±1/2 levels. Values of the hyperfine interaction constant and nuclear moment of 55Mn were derived from the six sets of data. For MnH, three sets of signals were detected: a proton ``matrix ENDOR'' line, transitions in the MS =0,±1 levels involving MI (55Mn)=1/2, 3/2, 5/2 levels, and proton transitions corresponding to νH and νH±aH. Analysis yielded the hyperfine constant aH =6.8(1) MHz and the nuclear quadrupole coupling constant Q'(55Mn)=-11.81(2) MHz. The latter compared favorably with a theoretical value derived earlier by Bagus and Schaefer. A higher term in the spin Hamiltonian appeared to be necessary to fit the proton hyperfine data.

  6. Experimental study of rf pulsed heating

    Directory of Open Access Journals (Sweden)

    Lisa Laurent

    2011-04-01

    Full Text Available Cyclic thermal stresses produced by rf pulsed heating can be the limiting factor on the attainable reliable gradients for room temperature linear accelerators. This is especially true for structures that have complicated features for wakefield damping. These limits could be pushed higher by using special types of copper, copper alloys, or other conducting metals in constructing partial or complete accelerator structures. Here we present an experimental study aimed at determining the potential of these materials for tolerating cyclic thermal fatigue due to rf magnetic fields. A special cavity that has no electric field on the surface was employed in these studies. The cavity shape concentrates the magnetic field on one flat surface where the test material is placed. The materials tested in this study have included oxygen free electronic grade copper, copper zirconium, copper chromium, hot isostatically pressed copper, single crystal copper, electroplated copper, Glidcop®, copper silver, and silver plated copper. The samples were exposed to different machining and heat treatment processes prior to rf processing. Each sample was tested to a peak pulsed heating temperature of approximately 110°C and remained at this temperature for approximately 10×10^{6} rf pulses. In general, the results showed the possibility of pushing the gradient limits due to pulsed heating fatigue by the use of copper zirconium and copper chromium alloys.

  7. Design Study for Pulsed Proton Beam Generation

    Directory of Open Access Journals (Sweden)

    Han-Sung Kim

    2016-02-01

    Full Text Available Fast neutrons with a broad energy spectrum, with which it is possible to evaluate nuclear data for various research fields such as medical applications and the development of fusion reactors, can be generated by irradiating proton beams on target materials such as beryllium. To generate short-pulse proton beam, we adopted a deflector and slit system. In a simple deflector with slit system, most of the proton beam is blocked by the slit, especially when the beam pulse width is short. Therefore, the available beam current is very low, which results in low neutron flux. In this study, we proposed beam modulation using a buncher cavity to increase the available beam current. The ideal field pattern for the buncher cavity is sawtooth. To make the field pattern similar to a sawtooth waveform, a multiharmonic buncher was adopted. The design process for the multiharmonic buncher includes a beam dynamics calculation and three-dimensional electromagnetic simulation. In addition to the system design for pulsed proton generation, a test bench with a microwave ion source is under preparation to test the performance of the system. The design study results concerning the pulsed proton beam generation and the test bench preparation with some preliminary test results are presented in this paper.

  8. Experimental study on performance of pulsed liquid jet pump

    International Nuclear Information System (INIS)

    Xu Weihui; Gao Chuanchang; Qin Haixia

    2010-01-01

    The device performance characteristics of transformer type pulsed liquid pump device were experimentally studied. The effects of the area ratio, work pressure and pulse parameters on the performance of the pulsed liquid jet pump device were performed in the tests. The potency of pulsed jet on improving the performance of the liquid jet pump device was also studied through the comparison with invariable jet pump at the same conditions. The results show that the pulsed jet can significantly improve the performance of transformer type jet pump devices. Area ratio and pulse parameters are the critical factors to the performance of the pulsed liquid jet pump device. The jet pump device performances are significantly improved by reducing the area ratio or by increasing the pulsed frequency. The flux characteristics of the pulsed liquid jet pump device presents the typical negative linear,the potency of pulsed jet in improving the performance of jet pump device with small area ratio can be more significant. The efficiency curve of pulsed liquid jet pump is similar to the parabola. At higher pulsed frequency, the top efficiency point of the pulsed jet pump moves to the higher flow ratio. The high efficiency area of the pulsed jet pump also is widened with the increase of the pulsed frequency. (authors)

  9. Pulsed-High Field/High-Frequency EPR Spectroscopy

    Science.gov (United States)

    Fuhs, Michael; Moebius, Klaus

    Pulsed high-field/high-frequency electron paramagnetic resonance (EPR) spectroscopy is used to disentangle many kinds of different effects often obscured in continuous wave (cw) EPR spectra at lower magnetic fields/microwave frequencies. While the high magnetic field increases the resolution of G tensors and of nuclear Larmor frequencies, the high frequencies allow for higher time resolution for molecular dynamics as well as for transient paramagnetic intermediates studied with time-resolved EPR. Pulsed EPR methods are used for example for relaxation-time studies, and pulsed Electron Nuclear DOuble Resonance (ENDOR) is used to resolve unresolved hyperfine structure hidden in inhomogeneous linewidths. In the present article we introduce the basic concepts and selected applications to structure and mobility studies on electron transfer systems, reaction centers of photosynthesis as well as biomimetic models. The article concludes with an introduction to stochastic EPR which makes use of an other concept for investigating resonance systems in order to increase the excitation bandwidth of pulsed EPR. The limited excitation bandwidth of pulses at high frequency is one of the main limitations which, so far, made Fourier transform methods hardly feasible.

  10. An ENDOR spectrum of H atoms in solid H{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Kumada, Takayuki; Kumagai, J.; Aratono, Yasuyuki; Miyazaki, T. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Kitagawa, N.; Noda, T.

    1998-10-01

    An ENDOR spectrum of H atoms produced in the {gamma}-rays irradiated solid H{sub 2} was measured at 4.2 K in order to elucidate the structures of the local environment of the H atoms in solid H{sub 2}. We found that the H atoms were not trapped in interstitial sites but in substitutional sites of the solid, and almost all ortho-H{sub 2} molecules at the first nearest sites from the H atoms converted into para-H{sub 2} molecules. This result shows that the ortho-para conversion is induced by electron spins of the H atoms. (author)

  11. Development of a Cardiovascular Simulator for Studying Pulse Diagnosis Mechanisms

    Directory of Open Access Journals (Sweden)

    Min Jang

    2017-01-01

    Full Text Available This research was undertaken to develop a cardiovascular simulator for use in the study of pulse diagnosis. The physical (i.e., pulse wave transmission and reflection and physiological (i.e., systolic and diastolic pressure, pulse pressure, and mean pressure characteristics of the radial pulse wave were reproduced by our simulator. The simulator consisted of an arterial component and a pulse-generating component. Computer simulation was used to simplify the arterial component while maintaining the elastic modulus and artery size. To improve the reflected wave characteristics, a palmar arch was incorporated within the simulator. The simulated radial pulse showed good agreement with clinical data.

  12. Pulse radiolysis study of egg white

    International Nuclear Information System (INIS)

    Micic, O.I.; Josimovic, L.; Markovic, V.

    1978-01-01

    Radiolytic processes in egg white in intervals of 0.1μs to several seconds have been studied by the pulse radiolysis technique. The formation and decay of short-lived intermediates and their absorption spectra were observed under varied experimental conditions. The results show that intermediates are produced predominantly in reactions of radicals formed in water radiolysis with egg white proteins. The intermediates decay mainly in the first-order intermolecular processes, though the mechanism of transformations is very complex. (author)

  13. Modeling study on the effects of pulse rise rate in atmospheric pulsed discharges

    Science.gov (United States)

    Zhang, Yuan-Tao; Wang, Yan-Hui

    2018-02-01

    In this paper, we present a modeling study on the discharge characteristics driven by short pulsed voltages, focusing on the effects of pulse rise rate based on the fluid description of atmospheric plasmas. The numerical results show that the breakdown voltage of short pulsed discharge is almost linearly dependent on the pulse rise rate, which is also confirmed by the derived equations from the fluid model. In other words, if the pulse rise rate is fixed as a constant, the simulation results clearly suggest that the breakdown voltage is almost unchanged, although the amplitude of pulsed voltage increases significantly. The spatial distribution of the electric field and electron density are given to reveal the underpinning physics. Additionally, the computational data and the analytical expression also indicate that an increased repetition frequency can effectively decrease the breakdown voltage and current density, which is consistent with the experimental observation.

  14. Explosive Nucleosynthesis Study Using Laser Driven γ-ray Pulses

    Directory of Open Access Journals (Sweden)

    Takehito Hayakawa

    2017-03-01

    Full Text Available We propose nuclear experiments using γ-ray pulses provided from high field plasma generated by high peak power laser. These γ-ray pulses have the excellent features of extremely short pulse, high intensity, and continuous energy distribution. These features are suitable for the study of explosive nucleosyntheses in novae and supernovae, such as the γ process and ν process. We discuss how to generate suitable γ-ray pulses and the nuclear astrophysics involved.

  15. Experimental study of rf pulsed heating

    CERN Document Server

    Laurent, L; Nantista, C; Dolgashev, V; Higashi, Y; Aicheler, M; Tantawi, S; Wuensch, W

    2011-01-01

    Cyclic thermal stresses produced by rf pulsed heating can be the limiting factor on the attainable reliable gradients for room temperature linear accelerators. This is especially true for structures that have complicated features for wakefield damping. These limits could be pushed higher by using special types of copper, copper alloys, or other conducting metals in constructing partial or complete accelerator structures. Here we present an experimental study aimed at determining the potential of these materials for tolerating cyclic thermal fatigue due to rf magnetic fields. A special cavity that has no electric field on the surface was employed in these studies. The cavity shape concentrates the magnetic field on one flat surface where the test material is placed. The materials tested in this study have included oxygen free electronic grade copper, copper zirconium, copper chromium, hot isostatically pressed copper, single crystal copper, electroplated copper, Glidcop (R), copper silver, and silver plated co...

  16. Molecular dynamics study of lubricant depletion by pulsed laser heating

    Science.gov (United States)

    Seo, Young Woo; Rosenkranz, Andreas; Talke, Frank E.

    2018-05-01

    In this study, molecular dynamics simulations were performed to numerically investigate the effect of pulsed laser heating on lubricant depletion. The maximum temperature, the lubricant depletion width, the number of evaporated lubricant beads and the number of fragmented lubricant chains were studied as a function of laser peak power, pulse duration and repetition rate. A continuous-wave laser and a square pulse laser were simulated and compared to a Gaussian pulse laser. With increasing repetition rate, pulsed laser heating was found to approach continuous-wave laser heating.

  17. Parametric study on femtosecond laser pulse ablation of Au films

    International Nuclear Information System (INIS)

    Ni Xiaochang; Wang Chingyue; Yang Li; Li Jianping; Chai Lu; Jia Wei; Zhang Ruobing; Zhang Zhigang

    2006-01-01

    Ablation process of 1 kHz rate femtosecond lasers (pulse duration 148 fs, wavelength 775 nm) with Au films on silica substrates has been systemically studied. The single-pulse threshold can be obtained directly. For the multiple pulses the ablation threshold varies with the number of pulses applied to the surface due to the incubation effect. From the plot of accumulated laser fluence N x φ th (N) and the number of laser pulses N, incubation coefficient of Au film can be obtained (s = 0.765). As the pulse energy is increased, the single pulse ablation rate is increasing following two ablation logarithmic regimes, which can be explained by previous research

  18. Laparoscopic appendicectomy using endo-ring applicator and fallope rings

    International Nuclear Information System (INIS)

    Ali, Iyoob V; Maliekkal, Joji I

    2009-01-01

    Wider adoption of laparoscopic appendicectomy (LA) is limited by problems in securing the appendiceal base as well as the cost and the duration compared with the open procedure. The objective of this study was to assess the feasibility and efficacy of a new method for securing the appendiceal base in LA, so as to make the entire procedure simpler and cheaper, and hence, more popular. Twenty-five patients who were candidates for appendicectomy (emergency as well as elective) and willing for the laparoscopic procedure were selected for this study. Ports used were 10 mm at the umbilicus, 5 mm at the lower right iliac fossa, and 10 mm at the left iliac fossa. Extremely friable, ruptured, or turgid organs of diameters larger than 8 mm were excluded from the study. The mesoappendix was divided close to the appendix by diathermy. Fallope rings were applied to the appendiceal base using a special ring applicator, and the appendix was divided and extracted through the lumen of the applicator. The procedure was successful in 23 (92%) cases, and the mean duration of the procedure was 20 minutes (15-32 minutes). There were no procedural complications seen during a median follow-up of two weeks. The equipment and rings were cheaper when compared with that of the standard methods of securing the base of the appendix. LA using fallope rings is a safe, simple, easy-to-learn, and economically viable method. (author)

  19. Spin-mapping of Coal Structures with ESE and ENDOR

    Science.gov (United States)

    Belford, R. L.; Clarkson, R. B.

    1989-12-01

    The broad goals of this project are to determine by nondestructive magnetic resonance methods chemical and physical structural characteristics of organic parts of native and treated coals. In this project period, we have begun to explore a technique which promises to enable us to follow to course of coal cleaning processes with microscopic spatial resolution. For the past five years, our laboratory has worked on extensions of the EPR technique as applied to coal to address these analytical problems. In this report we (1) describe the world's first nuclear magnetic resonance imaging results from an Illinois {number sign}6 coal and (2) transmit a manuscript describing how organic sulfur affect the very-high-frequency EPR spectra of coals. Magnetic resonance imaging (MRI) is a non-destructive technique that has found wide medical application as a means of visualizing the interior of human bodies. We have used MRI techniques to study the diffusion of an organic solvent (DMSO) into the pores of Illinois {number sign}6 coal. Proton MRI images reveal that this solvent at room temperature does not penetrate approximately 30% of the coal volume. Regions of the coal that exclude solvent could be related to inertinite and mineral components. A multi-technique imaging program is contemplated.

  20. Pulse radiolysis studies of model membranes

    International Nuclear Information System (INIS)

    Heijman, M.G.J.

    1984-01-01

    In this thesis the influence of the structure of membranes on the processes in cell membranes were examined. Different models of the membranes were evaluated. Pulse radiolysis was used as the technique to examine the membranes. (R.B.)

  1. Contamination Study of Micro Pulsed Plasma Thruster

    National Research Council Canada - National Science Library

    Kesenek, Ceylan

    2008-01-01

    .... Micro-Pulsed Plasma Thrusters (PPTs) are highly reliable and simple micro propulsion systems that will offer attitude control, station keeping, constellation flying, and drag compensation for such satellites...

  2. Heat pulse propagation studies in TFTR

    Energy Technology Data Exchange (ETDEWEB)

    Fredrickson, E.D.; Callen, J.D.; Colchin, R.J.; Efthimion, P.C.; Hill, K.W.; Izzo, R.; Mikkelsen, D.R.; Monticello, D.A.; McGuire, K.; Bell, J.D.

    1986-02-01

    The time scales for sawtooth repetition and heat pulse propagation are much longer (10's of msec) in the large tokamak TFTR than in previous, smaller tokamaks. This extended time scale coupled with more detailed diagnostics has led us to revisit the analysis of the heat pulse propagation as a method to determine the electron heat diffusivity, chi/sub e/, in the plasma. A combination of analytic and computer solutions of the electron heat diffusion equation are used to clarify previous work and develop new methods for determining chi/sub e/. Direct comparison of the predicted heat pulses with soft x-ray and ECE data indicates that the space-time evolution is diffusive. However, the chi/sub e/ determined from heat pulse propagation usually exceeds that determined from background plasma power balance considerations by a factor ranging from 2 to 10. Some hypotheses for resolving this discrepancy are discussed. 11 refs., 19 figs., 1 tab.

  3. Heat pulse propagation studies in TFTR

    International Nuclear Information System (INIS)

    Fredrickson, E.D.; Callen, J.D.; Colchin, R.J.

    1986-02-01

    The time scales for sawtooth repetition and heat pulse propagation are much longer (10's of msec) in the large tokamak TFTR than in previous, smaller tokamaks. This extended time scale coupled with more detailed diagnostics has led us to revisit the analysis of the heat pulse propagation as a method to determine the electron heat diffusivity, chi/sub e/, in the plasma. A combination of analytic and computer solutions of the electron heat diffusion equation are used to clarify previous work and develop new methods for determining chi/sub e/. Direct comparison of the predicted heat pulses with soft x-ray and ECE data indicates that the space-time evolution is diffusive. However, the chi/sub e/ determined from heat pulse propagation usually exceeds that determined from background plasma power balance considerations by a factor ranging from 2 to 10. Some hypotheses for resolving this discrepancy are discussed. 11 refs., 19 figs., 1 tab

  4. Pulse radiolysis studies in model lipid systems

    International Nuclear Information System (INIS)

    Patterson, L.K.; Hasegawa, K.

    1978-01-01

    The kinetic and spectral behavior of radicals formed by hydroxyl radical attack on linoleate anions has been studied by pulse radiolysis. Reactivity of OH toward this surfactant is an order of magnitude greater in monomeric form (kOH + linoleate = 8.0 x 10 9 M -1 sec -1 ) than in mecellar form (kOH + lin(micelle) = 1.0 x 10 9 M -1 sec -1 ). Abstraction of a hydrogen atom from the doubly allylic position gives rise to an intense absorption in the UV region (lambda max = 282-286 nm, epsilon approximately 3 x 10 4 M -1 cm -1 ) which may be used as a probe of radical activity at that site. This abstraction may occur, to a small extent, directly via OH attack. However, greater than 90% of initial attack occurs at other sites. Subsequent secondary abstraction of doubly allylic H atoms appears to occur predominantly by: (1) intramolecular processes in monomers, (2) intermolecular processes in micelles. Disappearance of radicals by secondary processes is slower in the micellar pseudo phase than in monomeric solution. (orig.) 891 HK 892 KR [de

  5. Pulsed EPR for studying silver clusters

    International Nuclear Information System (INIS)

    Michalik, J.; Wasowicz, T.; Sadlo, J.; Reijerse, E.J.; Kevan, L.

    1996-01-01

    The cationic silver clusters of different nuclearity have been produced by radiolysis of zeolite A and SAPO molecular sieves containing Ag + as exchangeable cations. The pulsed EPR spectroscopy has been applied for studying the local environment of silver cluster in order to understand the mechanism of cluster formation and stabilization. the electron spin echo modulation (ESEM) results on Ag 6 n+ cluster in dehydration zeolite A indicate that the hexameric silver is stabilized only in sodalite cages which are surrounded by α-cages containing no water molecules. Trimeric silver clusters formed in hydrated A zeolites strongly interact with water, thus the paramagnetic center can be considered as a cluster-water adduct. In SAPO-molecular sieves, silver clusters are formed only in the presence of adsorbed alcohol molecules. From ESEM it is determined that Ag 4 n+ in SAPO-42 is stabilized in α cages, where it is directly coordinated by two methanol molecules. Dimeric silver, Ag 2 + in SAPO-5 and SAPO-11 is located in 6-ring channels and interacts with three CH 3 OH molecules, each in different 10 ring or 12 ring channels. The differences of Ag 2 + stability in SAPO-5 and SAPO-11 are also discussed. (Author)

  6. A pulse radiolysis study of emulsion polymerization

    International Nuclear Information System (INIS)

    McAskill, N.A.

    1976-01-01

    The emulsion polymerisation of slightly water soluble monomers such as styrene occurs initially in micelles of surfactant swollen with monomer and later in larger particles consisting of polymer swollen with monomer and stabilized with an outer layer of surfactant. There is considerable controversy on whether the reaction sites of polymerization are inside or on the surface of the particle or micelle. The relative amounts of micelle and particles present at various stages of the polymerization are also nuclear. In the present study the OH radical formed by pulse radiolysis has been used as a probe to investigate the site of solubilization of styrene in various surfactant micelles. Two products can be distinguished by UV spectrometry, a benzyl type radical formed by OH addition to the side chain of styrene and a cyclohexadienyl type radical formed by addition to the ring. Wide differences in the relative amounts of each product were observed suggesting that in some surfactants the styrene ring is buried inside the micelle whilst in other systems the styrene appears to be so solubilized at the interface leaving both the ring and the side chain open to attack by the OH radical. (author)

  7. Studying dense plasmas with coherent XUV pulses

    International Nuclear Information System (INIS)

    Stabile, H.

    2006-12-01

    The investigation of dense plasma dynamic requires the development of diagnostics able to ensure the measurement of electronic density with micro-metric space resolution and sub-nanosecond, or even subpicosecond, time resolution (indeed this must be at least comparable with the characteristic tune scale of plasma evolution). In contrast with low-density plasmas, dense plasmas cannot be studied using optical probes in the visible domain, the density range accessible being limited to the critical density (N c equals 1.1*10 21 λ -2 (μm) ∼ 10 21 cm -3 for infrared). In addition, light is reflected even at smaller densities if the medium exhibits sharp density gradients. Hence probing of dense plasmas, for instance those produced by laser irradiation of solids, requires using shorter wavelength radiation. Thanks to their physical properties, high order harmonics generated in rare gases are particularly adapted to the study of dense plasmas. Indeed, they can naturally be synchronized with the generating laser and their pulse duration is very short, which makes it possible to use them in pump-probe experiments. Moreover, they exhibit good spatial and temporal coherencies. Two types of diagnostics were developed during this thesis. The first one was used to study the instantaneous creation of hot-solid-density plasma generated by focusing a femtosecond high-contrast laser on an ultra-thin foil (100 nm) in the 10 18 W/cm 2 intensity regime. The use of high order harmonics, providing a probe beam of sufficiently short wavelengths to penetrate such a medium, enables the study of its dynamics on the 100 fs time scale. The second one uses the harmonics beam as probe beam (λ equals 32 nm) within an interferometric device. This diagnostic was designed to ensure a micro-metric spatial resolution and a temporal resolution in the femtosecond range. The first results in presence of plasma created by irradiation of an aluminum target underline the potentialities of this new

  8. Study on the Depth, Rate, Shape, and Strength of Pulse with Cardiovascular Simulator

    Directory of Open Access Journals (Sweden)

    Ju-Yeon Lee

    2017-01-01

    Full Text Available Pulse diagnosis is important in oriental medicine. The purpose of this study is explaining the mechanisms of pulse with a cardiovascular simulator. The simulator is comprised of the pulse generating part, the vessel part, and the measurement part. The pulse generating part was composed of motor, slider-crank mechanism, and piston pump. The vessel part, which was composed with the aorta and a radial artery, was fabricated with silicon to implement pulse wave propagation. The pulse parameters, such as the depth, rate, shape, and strength, were simulated. With changing the mean pressure, the floating pulse and the sunken pulse were generated. The change of heart rate generated the slow pulse and the rapid pulse. The control of the superposition time of the reflected wave generated the string-like pulse and the slippery pulse. With changing the pulse pressure, the vacuous pulse and the replete pulse were generated. The generated pulses showed good agreements with the typical pulses.

  9. ENDOR investigations of the Ce.sup.3+./sup. ions in YAG: Transferred hyperfine interaction with nearest aluminum ions

    Czech Academy of Sciences Publication Activity Database

    Azamat, Dmitry; Badalyan, A. G.; Feng, D.H.; Lančok, Ján; Jastrabík, Lubomír; Dejneka, Alexandr; Baranov, P. G.; Yakovlev, D.R.; Bayer, M.

    2017-01-01

    Roč. 122, č. 24 (2017), s. 1-3, č. článku 243903. ISSN 0021-8979 R&D Projects: GA MŠk LO1409; GA ČR GA16-22092S Institutional support: RVO:68378271 Keywords : ENDOR * Ce 3+ ions in YAG * transferred hyperfine interactions Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 2.068, year: 2016

  10. 13C ENDOR Spectroscopy of Lipoxygenase-Substrate Complexes Reveals the Structural Basis for C-H Activation by Tunneling.

    Science.gov (United States)

    Horitani, Masaki; Offenbacher, Adam R; Carr, Cody A Marcus; Yu, Tao; Hoeke, Veronika; Cutsail, George E; Hammes-Schiffer, Sharon; Klinman, Judith P; Hoffman, Brian M

    2017-02-08

    In enzymatic C-H activation by hydrogen tunneling, reduced barrier width is important for efficient hydrogen wave function overlap during catalysis. For native enzymes displaying nonadiabatic tunneling, the dominant reactive hydrogen donor-acceptor distance (DAD) is typically ca. 2.7 Å, considerably shorter than normal van der Waals distances. Without a ground state substrate-bound structure for the prototypical nonadiabatic tunneling system, soybean lipoxygenase (SLO), it has remained unclear whether the requisite close tunneling distance occurs through an unusual ground state active site arrangement or by thermally sampling conformational substates. Herein, we introduce Mn 2+ as a spin-probe surrogate for the SLO Fe ion; X-ray diffraction shows Mn-SLO is structurally faithful to the native enzyme. 13 C ENDOR then reveals the locations of 13 C10 and reactive 13 C11 of linoleic acid relative to the metal; 1 H ENDOR and molecular dynamics simulations of the fully solvated SLO model using ENDOR-derived restraints give additional metrical information. The resulting three-dimensional representation of the SLO active site ground state contains a reactive (a) conformer with hydrogen DAD of ∼3.1 Å, approximately van der Waals contact, plus an inactive (b) conformer with even longer DAD, establishing that stochastic conformational sampling is required to achieve reactive tunneling geometries. Tunneling-impaired SLO variants show increased DADs and variations in substrate positioning and rigidity, confirming previous kinetic and theoretical predictions of such behavior. Overall, this investigation highlights the (i) predictive power of nonadiabatic quantum treatments of proton-coupled electron transfer in SLO and (ii) sensitivity of ENDOR probes to test, detect, and corroborate kinetically predicted trends in active site reactivity and to reveal unexpected features of active site architecture.

  11. ESR and ENDOR of free radicals in γ-irradiated single crystals of trimethoprim at room temperature

    International Nuclear Information System (INIS)

    Krzyminiewski, R.; Kawacka, U.; Pietrzak, J.; Erickson, R.; Lund, A.

    1995-01-01

    Singe crystals of trimethoprim were examined after γ-irradiation at room temperature by ESR and ENDOR spectroscopy. A radicals is formed by abstraction of a hydrogen atom from the CH 2 group of the bridge. The unpaired electron is delocalized mainly onto the trimethoxybenzyl ring. It interacts with one proton of the bridge and with two protons in the trimethoxybenzyl ring. (au) (14 refs.)

  12. Studies of nonlinear femtosecond pulse propagation in bulk materials

    Science.gov (United States)

    Eaton, Hilary Kaye

    2000-10-01

    Femtosecond pulse lasers are finding widespread application in a variety of fields including medical research, optical switching and communications, plasma formation, high harmonic generation, and wavepacket formation and control. As the number of applications for femtosecond pulses increases, so does the need to fully understand the linear and nonlinear processes involved in propagating these pulses through materials under various conditions. Recent advances in pulse measurement techniques, such as frequency-resolved optical gating (FROG), allow measurement of the full electric field of the pulse and have made detailed investigations of short- pulse propagation effects feasible. In this thesis, I present detailed experimental studies of my work involving nonlinear propagation of femtosecond pulses in bulk media. Studies of plane-wave propagation in fused silica extend the SHG form of FROG from a simple pulse diagnostic to a useful method of interrogating the nonlinear response of a material. Studies of nonlinear propagation are also performed in a regime where temporal pulse splitting occurs. Experimental results are compared with a three- dimensional nonlinear Schrödinger equation. This comparison fuels the development of a more complete model for pulse splitting. Experiments are also performed at peak input powers above those at which pulse splitting is observed. At these higher intensities, a broadband continuum is generated. This work presents a detailed study of continuum behavior and power loss as well as the first near-field spatial- spectral measurements of the generated continuum light. Nonlinear plane-wave propagation of short pulses in liquids is also investigated, and a non-instantaneous nonlinearity with a surprisingly short response time of 10 fs is observed in methanol. Experiments in water confirm that this effect in methanol is indeed real. Possible explanations for the observed effect are discussed and several are experimentally rejected. This

  13. Kinetic studies on a repetitively pulsed fast reactor

    International Nuclear Information System (INIS)

    Das, S.

    1982-01-01

    Neutronic analysis of an earlier proposed periodically pulsed fast reactor at Kalpakkam (KPFR) has been carried out numerically under equilibrium and transient conditions using the one-point model of reactor kinetics and the experimentally measured total worth of reactivity modulator, the parabolic coefficient of reactivity of the movable reflector and the mean prompt neutron lifetime. Results of steady-state calculations - treated on the basis of delayed neutron precursor and energy balances during a period of operation - have been compared with the analytical formulae of Larrimore for a parabolic reactivity input. Empirical relations for half-width of the fast neutron pulse, the peak pulse power and the power at first crossing of prompt criticality have been obtained and shown to be accurate enough for predicting steady-state power pulse characteristics of a periodically pulsed fast reactor. The concept of a subprompt-critical reactor has been used to calculate the fictitious delayed neutron fraction, β of the KPFR through a numerical experiment. Relative pulse height stability and pulse shape sensitivity to changes of maximum reactivity is discussed. With the aid of new safety concepts, the Power Amplification Factor (PAF) and the Pulse Growth Factor (Rsub(p)), the dynamics KPFR under accidental conditions has been studied for step and ramp reactivity perturbations. All the analysis has been done without taking account of reactivity feedback. (orig.)

  14. Studies on pulsed hollow cathode capillary discharges

    Energy Technology Data Exchange (ETDEWEB)

    Choi, P; Dumitrescu-Zoita, C; Larour, J; Rous, J [Ecole Polytechnique, 91 - Palaiseau (France). Lab. de Physique des Milieux Ionises; Favre, M; Moreno, J; Chuaqui, H; Wyndham, E [Pontificia Univ. Catolica de Chile, Santiago (Chile). Facultad de Fisica; Zambra, M [Comision Chilena de Energia Nuclear, Santiago (Chile); Wong, C S [Univ. of Malaya, Kuala Lumpur (Malaysia). Plasma Research Lab

    1997-12-31

    Preliminary results on radiation characteristics of pulsed hollow cathode capillary discharges are presented. The device combines the on axis electron beam assisted ionization capabilities of the transient hollow cathode discharge with a novel high voltage low inductance geometrical design, which integrates the local energy storage into the electrode system. A nanosecond regime high temperature plasma is produced in a long, high aspect ratio capillary, with light emission in the UV to XUV region. The discharge is operated from near vacuum to pressure in the 1000 mTorr range. (author). 2 figs., 7 refs.

  15. A Multidisciplinary Study of Pulse Detonation Engine Propulsion

    National Research Council Canada - National Science Library

    Santoro, Robert

    2003-01-01

    ... chemistry, injector and flow field mixing, and advanced diagnostics to study the fundamental phenomena of importance under both static and dynamic conditions representative of actual pulse detonation engine operation...

  16. Terahertz pulsed imaging study of dental caries

    Science.gov (United States)

    Karagoz, Burcu; Altan, Hakan; Kamburoglu, Kıvanç

    2015-07-01

    Current diagnostic techniques in dentistry rely predominantly on X-rays to monitor dental caries. Terahertz Pulsed Imaging (TPI) has great potential for medical applications since it is a nondestructive imaging method. It does not cause any ionization hazard on biological samples due to low energy of THz radiation. Even though it is strongly absorbed by water which exhibits very unique chemical and physical properties that contribute to strong interaction with THz radiation, teeth can still be investigated in three dimensions. Recent investigations suggest that this method can be used in the early identification of dental diseases and imperfections in the tooth structure without the hazards of using techniques which rely on x-rays. We constructed a continuous wave (CW) and time-domain reflection mode raster scan THz imaging system that enables us to investigate various teeth samples in two or three dimensions. The samples comprised of either slices of individual tooth samples or rows of teeth embedded in wax, and the imaging was done by scanning the sample across the focus of the THz beam. 2D images were generated by acquiring the intensity of the THz radiation at each pixel, while 3D images were generated by collecting the amplitude of the reflected signal at each pixel. After analyzing the measurements in both the spatial and frequency domains, the results suggest that the THz pulse is sensitive to variations in the structure of the samples that suggest that this method can be useful in detecting the presence of caries.

  17. Subpicosecond pulse radiolysis studies on spur reactions and nanotechnology

    International Nuclear Information System (INIS)

    Tagawa, S.

    2003-01-01

    Recently we developed a subpicosecond pulse radiolysis system, although the time resolution of pulse radiolysis had remained about 30 ps for these 30 years. Time resolution and S/N ratio have been improved dramatically. The subpicosecond pulse radiolysis is a very powerful method to detect and observe transient phenomena in radiation chemistry and physics within 30 ps. By using the subpicosecond pulse radiolysis, many researches have been carried out on ultrafast phenomena in radiation chemistry, physics, biology and applied fields such as material science.Especially the spur reaction, which is one of the most important reactions in radiation chemistry, physics and biology, has been studied in the very wide time range from subpicosecond to several hundred nanoseconds by very high S/N ratio. These experimental results were analyzed theoretically and applied to the basic data for nanofabrication, which are very important in both next generation lithography and nanotechnology

  18. Experimental study of pulsed heating of electromagnetic cavities

    International Nuclear Information System (INIS)

    Pritzkau, D.P.; Menegat, A.; Siemann, R.H.

    1997-01-01

    An experiment to study the effects of pulsed heating in electromagnetic cavities will be performed. Pulsed heating is believed to be the limiting mechanism of high acceleration gradients at short wavelengths. A cylindrical cavity operated in the TE 011 mode at a frequency of 11.424 GHz will be used. A klystron will be used to supply a peak input power of 20 MW with a pulse length of 1.5 μs. The temperature response of the cavity will be measured by a second waveguide designed to excite a TE 012 mode in the cavity with a low-power CW signal at a frequency of 17.8 GHz. The relevant theory of pulsed heating will be discussed and the results from cold-testing the structure will be presented

  19. Giant Pulse Studies of Ordinary and Recycled Pulsars with NICER

    Science.gov (United States)

    Lewandowska, Natalia; Arzoumanian, Zaven; Gendreau, Keith C.; Enoto, Teruaki; Harding, Alice; Lommen, Andrea; Ray, Paul S.; Deneva, Julia; Kerr, Matthew; Ransom, Scott M.; NICER Team

    2018-01-01

    Radio Giant Pulses are one of the earliest discovered form of anomalous single pulse emission from pulsars. Known for their non-periodical occurrence, restriction to certain phase ranges, power-law intensity distributions, pulse widths ranging from microseconds to nanoseconds and very high brightness temperatures, they stand out as an individual form of pulsar radio emission.Discovered originally in the case of the Crab pulsar, several other pulsars have been observed to emit radio giant pulses, the most promising being the recycled pulsar PSR B1937+21 and also the Vela pulsar.Although radio giant pulses are apparently the result of a coherent emission mechanism, recent studies of the Crab pulsar led to the discovery of an additional incoherent component at optical wavelengths. No such component has been identified for recycled pulsars, or Vela yet.To provide constraints on possible emission regions in their magnetospheres and to search for differences between giant pulses from ordinary and recycled pulsars, we present the progress of the correlation study of PSR B1937+21 and the Vela pulsar carried out with NICER and several radio observatories.

  20. Pulse radiolysis study on several fluoroquinolones

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Peng [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Graduate University of Chinese Academy of Science, Beijing 100049 (China); Yao Side [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Li Haixia; Song Xiyu; Liu Yancheng [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Graduate University of Chinese Academy of Science, Beijing 100049 (China); Wang Wenfeng, E-mail: wangwenfeng@sinap.ac.c [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China)

    2011-04-15

    Reactions of several fluoroquinolones (FQs), including enoxacin, norfloxacin, and ciprofloxacin, with various reactive species such as e{sub aq}{sup -}, N{sup {center_dot}}{sub 3}, and {sup {center_dot}O}H are investigated by pulse radiolysis techniques. The FQ radical anions formed in the reactions of FQs with e{sub aq}{sup -} could either be protonated or deprotonated, and the absorption of FQ radical anions was located around 370 nm. The absorption of the neutral radicals produced in the protonation, and the radical dianions produced in the deprotonation of FQ radical anions were located in the 500-750 nm region. The FQ radical cations formed in the reactions of FQs with N{sub 3}{sup {center_dot}} showed an absorption band around 360 nm. Due to the strong bleaching below 350 nm, the absorption maxima ({lambda}{sub max}) of FQ radical anions, and the {lambda}{sub max} of FQ radical cations were not confirmed. The absorption of the FQ radical anions and cations was clearly pH dependent. Under neutral conditions, the reaction rate constants of FQs with e{sub aq}{sup -} and {sup {center_dot}O}H, which are diffusion controlled, were determined.

  1. Redox reaction studies by nanosecond pulse radiolysis

    International Nuclear Information System (INIS)

    Moorthy, P.N.

    1979-01-01

    Free radicals are formed as intermediates in many chemical and biochemical reactions. An important type of reaction which they can undergo is a one electron or redox process. The direction and rate of such electron transfer reactions is governed by the relative redox potentials of the participating species. Because of the generally short lived nature of free radicals, evaluation of their redox potentials poses a number of problems. Two techniques are described for the experimental determination of the redox potentials of short lived species generated by either a nanosecond electron pulse or laser flash. In the first method, redox titration of the short lived species with stable molecules of known redox potential is carried out, employing the technique of fast kinetic spectrophotometry. Conversely, by the same method it is also possible to evaluate the one electron redox potentials of stable molecules by redox titration with free radicals of known redox potential produced as above. In the second method, electrochemical reduction or oxidation of the short lived species at an appropriate electrode (generally a mercury drop) is carried out at different fixed potentials, and the redox potential evaluated from the current-potential curves (polarograms). Full description of the experimental set up and theoretical considerations for interpretation of the raw data are given. The relative merits of the two methods and their practical applicability are discussed. (auth.)

  2. Preliminary study of pseudorandom binary sequence pulsing of ORELA

    International Nuclear Information System (INIS)

    Larson, N.M.; Olsen, D.K.

    1980-03-01

    It has been suggested that pseudorandom binary sequence (PRBS) pulsing might enhance the performance of the Oak Ridge Electron Linear Accelerator (ORELA) for neutron-induced, time-of-flight (TOF) cross-section measurements. In this technical memorandum, equations are developed for expected count rates, statistical variances, and backgrounds for a pulsing scheme in which a PRBS is superimposed on the periodic equalintensity ORELA bursts. Introduction of the PRBS modification permits neutrons of different energies originating from different bursts to reach the detector simultaneously, and the signal corresponding to a unique flight time to be extracted mathematically. Relative advantages and disadvantages of measurements from conventional and PRBS pulsing modes are discussed in terms of counting statistics and backgrounds. Computer models of TOF spectra are generated for both pulsing modes, using as examples a 20-meter 233 U fission-chamber measurement and a 155-meter 238 U sample-in transmission measurement. Detailed comparisons of PRBS vs conventional results are presented. This study indicates that although PRBS pulsing could enhance ORELA performance for selected measurements, for general ORELA operation the disadvantages from PRBS pulsing probably outweigh the advantages

  3. Comparative study on Pulsed Laser Deposition and Matrix Assisted Pulsed Laser Evaporation of urease thin films

    International Nuclear Information System (INIS)

    Smausz, Tomi; Megyeri, Gabor; Kekesi, Renata; Vass, Csaba; Gyoergy, Eniko; Sima, Felix; Mihailescu, Ion N.; Hopp, Bela

    2009-01-01

    Urease thin films were produced by Matrix Assisted Pulsed Laser Evaporation (MAPLE) and Pulsed Laser Deposition from two types of targets: frozen water solutions of urease with different concentrations (1-10% m/v) and pure urease pellets. The fluence of the ablating KrF excimer laser was varied between 300 and 2200 mJ/cm 2 . Fourier transform infrared spectra of the deposited films showed no difference as compared to the original urease. Morphologic studies proved that the films consist of a smooth 'base' layer with embedded micrometer-sized droplets. Absorption-coefficient measurements contradicted the traditional 'absorptive matrix' model for MAPLE deposition. The laser energy was absorbed by urease clusters leading to a local heating-up and evaporation of the frozen matrix from the uppermost layer accompanied by the release of dissolved urease molecules. Significant enzymatic activity of urease was preserved only during matrix assisted transfer.

  4. Pulsed total dose damage effect experimental study on EPROM

    International Nuclear Information System (INIS)

    Luo Yinhong; Yao Zhibin; Zhang Fengqi; Guo Hongxia; Zhang Keying; Wang Yuanming; He Baoping

    2011-01-01

    Nowadays, memory radiation effect study mainly focus on functionality measurement. Measurable parameters is few in china. According to the present situation, threshold voltage testing method was presented on floating gate EPROM memory. Experimental study of pulsed total dose effect on EPROM threshold voltage was carried out. Damage mechanism was analysed The experiment results showed that memory cell threshold voltage negative shift was caused by pulsed total dose, memory cell threshold voltage shift is basically coincident under steady bias supply and no bias supply. (authors)

  5. Nuclear fuel safety studies by laser pulse heating

    International Nuclear Information System (INIS)

    Viswanadham, C.S.; Kumar, Santosh; Dey, G.K.; Kutty, T.R.G.; Khan, K.B.; Kumar, Arun; Jathar, V.P.; Sahoo, K.C.

    2009-01-01

    The behaviour of nuclear fuels under transient heating conditions is vital to nuclear safety. A laser pulse based heating system to simulate the transient heating conditions experienced by the fuel during reactor accidents like LOCA and RIA is under development at BARC, Mumbai. Some of the concepts used in this system are under testing in pilot studies. This paper describes the results of some pilot studies carried out on unirradiated UO 2 specimens by laser pulse heating, followed by metallography and X-ray diffraction measurements. (author)

  6. In vitro studies with a pulsed neodymium/YAG laser.

    Science.gov (United States)

    Venkatesh, S; Guthrie, S; Foulds, W S; Lee, W R; Cruickshank, F R; Bailey, R T

    1985-02-01

    The relationships between the destructive effects of Q-switched Nd/YAG laser pulses and a number of experimental parameters were studied for various target materials including in particular excised, fixed samples of human trabecular meshwork. The laser parameters altered were the pulse energy, the convergence angle of the focused beam, and the position of the focus of the beam relative to the target's axial position. The main finding was that it was possible to make deep holes, of a diameter less than 100 micron, in virtually transparent samples of trabecular meshwork with a laser delivery system of 6 degrees convergence and pulse energies of 14 mJ or more. The relevance of this and the other experimental results to the development of a reliable system for performing internal trabeculotomies for the treatment of open-angle glaucoma is presented.

  7. Study of pulse shapes in Ge detectors with PET

    Energy Technology Data Exchange (ETDEWEB)

    Grabmayr, Peter; Hegai, Alexander; Jochum, Josef; Schmitt, Christopher; Schuetz, Ann-Kathrin [Eberhard Karls Univeritaet Tuebingen (Germany); Collaboration: GERDA-Collaboration

    2016-07-01

    The Gerda collaboration aims to determine the half life of the neutrinoless double beta decay (0νββ) of {sup 76}Ge. For Phase II Gerda wants to reduce the background contribution significantly by active background-suppression techniques. One of such techniques is the pulse shape analysis of signals induced by the interaction of radiation with the detector. The pulse shapes depend not only on the energy of the interacting gamma, the geometry and field configuration but also on the location of interaction in the crystal. The waveform and the location of the interaction in the germanium can be determined by positron-emission-tomography (PET). First results of this novel pulse shape study with the PET will be presented in this talk.

  8. Studies of Pulsed Signals in High-precision Experiments (Antarctica

    Directory of Open Access Journals (Sweden)

    Shapovalov S. N.,

    2013-07-01

    Full Text Available The paper presents the results of studies on pulsed signals in photocurrent (PCC-2 instrument, in the 565-nm LED spectrum, and in the atmospheric zenith spectrum (342.5 nm. According to the results of statistical analysis of data measurements for the period from 24.04.04 till 01.02.06 a correlation between the temporal distribution of pulsed signals in photocurrent PCC-2 and CA F10.7 cm (2800 MHz index and the total solar radiation (TSI was established. In the course of the parallel measurements of photocurrent in PCC-2 and fluctuations in the spectra frequencies of the LED and the atmosphere zenith, based on the average daily values of the standard deviation, the identical trend in the photocurrent pulse signals (PCC-2 and the fluctuations at 520-nm LED spectrum and 342.5-nm atmosphere zenith spectrum was detected (AvaSpec–2048 spectrometer.

  9. Study on high gain broadband optical parametric chirped pulse amplification

    International Nuclear Information System (INIS)

    Zhang, S.K.; Fujita, M.; Yamanaka, C.; Yoshida, H.; Kodama, R.; Fujita, H.; Nakatsuka, M.; Izawa, Y.

    2000-01-01

    Optical parametric chirped pulse amplification has apparent advantages over the current schemes for high energy ultrashort pulse amplification. High gain in a single pass amplification, small B-integral, low heat deposition, high contrast ratio and, especially the extremely broad gain bandwidth with large-size crystals available bring people new hope for over multi-PW level at which the existing Nd:glass systems suffered difficulties. In this paper we present simulation and experimental studies for a high gain optical parametric chirped pulse amplification system which may be used as a preamplifier to replace the current complicated regenerative system or multi-pass Ti:sapphire amplifiers. Investigations on the amplification bandwidth and gain with BBO are performed. Analysis and discussions are also given. (author)

  10. Study of laser pulses propagation through an ultrashort pulse amplifying systems for the development of an Offner temporal stretcher

    International Nuclear Information System (INIS)

    Cordeiro, Thiago da Silva

    2009-01-01

    The study of laser pulses propagation through an ultrashort pulses amplifying system containing dispersive and spectral modifying media was performed. The study emphasis was the development of an ultrashort pulse stretcher to replace the one inside a hybrid Ti:Sapphire/Cr:LiSAF CPA system operating at the Center for Lasers and Applications at IPEN/CNEN-SP. A spherical aberration free Offner stretcher was theoretically studied, aiming to obtain a stretching ratio larger than the one available in our system. The influence of the phase components in the amplified pulse final duration was also studied, and the bandwidth limiting elements of the system in operation were mapped, with the purpose of determining the conditions under which a new stretcher should be implemented. Based on the actual measurements, computing routines were implemented in order to determine the consequences of an ultrashort pulse travelling through a bandwidth limiting component. (author)

  11. Pulse radiolysis study on aqueous solution of nicotine

    International Nuclear Information System (INIS)

    Wang Shilong; Mei Wang; Ni Yaming; Yao Side; Wang Wenfeng

    2004-01-01

    Nicotine has been studied for the first time by pulse radiolysis techniques. It has been found that hydrated electrons, hydrogen radicals and hydroxyl radicals can react with nicotine to produce anion radicals and neutral radicals, respectively, and the related rate constants have been determined. (authors)

  12. Spectroscopic studies of pulsed-power plasmas

    International Nuclear Information System (INIS)

    Maron, Y.; Arad, R.; Dadusc, G.; Davara, G.; Duvall, R.E.; Fisher, V.; Foord, M.E.; Fruchtman, A.; Gregorian, L.; Krasik, Ya.

    1993-01-01

    Recently developed spectroscopic diagnostic techniques are used to investigate the plasma behavior in a Magnetically Insulated Ion Diode, a Plasma Opening Switch, and a gas-puffed Z-pinch. Measurements with relatively high spectral, temporal, and spatial resolutions are performed. The particle velocity and density distributions within a few tens of microns from the dielectric-anode surface are observed using laser spectroscopy. Collective fluctuating electric fields in the plasma are inferred from anisotropic Stark broadening. For the Plasma Opening Switch experiment, a novel gaseous plasma source was developed which is mounted inside the high-voltage inner conductor. The properties of this source, together with spectroscopic observations of the electron density and particle velocities of the injected plasma, are described. Emission line intensities and spectral profiles give the electron kinetic energies during the switch operation and the ion velocity distributions. Secondary plasma ejection from the electrodes is also studied. In the Z-pinch experiment, spectral emission-line profiles are studied during the implosion phase. Doppler line shifts and widths yield the radial velocity distributions for various charge states in various regions of the plasma. Effects of plasma ejection from the cathode are also studied

  13. Pulse radiolysis study of aqueous cyanamide solutions

    International Nuclear Information System (INIS)

    Draganic, I.G.; Draganic, Z.D.; Sehested, K.

    1978-01-01

    The radiolysis of oxygen-free, aqueous solutions of cyanamide was studied by fast kinetic spectrophotometry. Computer simulation of the reaction mechanisms was used to evaluate the experimental data. Four different species are identified: (1) the radical anion (NH 2 CN) - absorbing light in the UV with lambda/sub max/ 240 = 1500 M -1 cm -1 ; the disappearance is a second-order process with 2k = 1.3 x 10 9 M -1 s -1 ; (2) the hydrogen adduct, NH 2 C(H) double bond N (or NH 2 C double bond NH), with lambda/sub max/ 300 nm and epsilon 300 = 150 M -1 cm -1 decaying by second-order kinetics with 2k = 3.1 x 10 9 M -1 s -1 ; (3) the hydroxyl radical preferentially adds to the cyano group, NH 2 C(OH) double bond N (or NH 2 C double bond NOH). This species rearranges in the submicrosecond scale to NH 2 C ( double bond O) NH (lambda/sub max/ 325 nm and epsilon/sub 325 = 1900 M -1 cm -1 ) and disappears by a second-order process with 2k = 6.3 x 10 9 M -1 s -1 . (4) It is estimated that about 10% of OH radicals attack the substituent group and by H abstraction produce the NHCN radical (lambda/sub max/ 370 nm and epsilon 370 = 1800 M -1 cm -1 ); it disappears by a pseudo-first-order process attributed to a hydrolysis reaction. At increasing acidities, protonation of this radical takes place, NHCN + H + → + NH 2 CN; the protonated form decays faster and absorbs more strongly. In a cyanamide solution containing S 2 O 8 2- , the SO - 4 . radicals react with cyanamide, k = 1 x 10 8 M -1 s -1 , producing + NH 2 CN radicals. The dependence of the optical density at 325 nm on the dose rate and solute concentration are quantitatively consistent with the assumption that the OH radicals react with the NH 2 C(=O)NH species with k = 4 x 10 9 M -1 s -1

  14. Comparative Study Between Intense Pulsed Light IPLAND Pulsed Dye Laser In The Treatment Of Striae Distensae

    International Nuclear Information System (INIS)

    El-Khalafawy, Gh.M.K.A.

    2013-01-01

    Pulsed dye laser (PDL) and Intense Pulsed Light (IPL) have been used to treat Striae Distensae (SD). Thirty patients with age ranging from 14 - 42 years were included in this study. Twenty patients were treated on one side of their bodies with PDL and on the other side with IPL while seven patients were treated on both sides by IPL and three patients were treated on both sides by PDL for five sessions with four weeks interval between sessions. Skin biopsies were stained with H and E, Masson Trichrome, Orcein, Alcian blue and anti-collagen I Α1. After both PDL and IPL treatments striae width was decreased and the texture was improved in a highly significant manners where P value was 0.001. Collagen expression was increased in a highly significant manner and P values were <0.001 and 0.004 after PDL and IPL treatments respectively. However, PDL induced expression of collagen I in a highly significant manner compared to the treatment with IPL where P values were <0.001 and 0.193 respectively. Striae rubra gave a superior response with either PDL or IPL compared to striae alba which was evaluated clinically by the width, color and texture, although the histological changes could not verify this consequence. Both PDL and IPL can enhance the clinical picture of striae through collagen stimulation therapeutic modalities

  15. Nonlinear scattering in hard tissue studied with ultrashort laser pulses

    International Nuclear Information System (INIS)

    Eichler, J.; Kim, B.M.

    2002-01-01

    The back-scattered spectrum of ultrashort laser pulses (800 nm, 0.2 ps) was studied in human dental and other hard tissues in vitro below the ablation threshold. Frequency doubled radiation (SHG), frequency tripled radiation and two-photon fluorescence were detected. The relative yield for these processes was measured for various pulse energies. The dependence of the SHG signal on probe thickness was determined in forward and back scattering geometry. SHG is sensitive to linear polarization of the incident laser radiation. SHG in human teeth was studied in vitro showing larger signals in dentin than in cementum and enamel. In carious areas no SHG signal could be detected. Possible applications of higher harmonic radiation for diagnostics and microscopy are discussed. (orig.)

  16. Study of polysilane mainchain electronic structure by picosecond pulse radiolysis

    International Nuclear Information System (INIS)

    Habara, H.; Saeki, A.; Kunimi, Y.; Seki, S.; Kozawa, T.; Yoshida, Y.; Tagawa, S.

    2000-01-01

    The electronic structure of a charged polysilane molecle is studied. The transient absorption spectroscopy was carried out for charged radicals of poly (methylphenylsilane): PMPS by pico-second and nanosecond pulse radiolysis technique. It was observed that the peak of the transient absorption spectra shifted to longer wavelength region within a few nsec, and an increase was observed in the optical density at 370 nm, which had been already assigned to the radical anions of PMPS. It is ascribed to inter-segment electron transfer (intra-molecular transfer) through polymer chain. The nanosecond pulse radiolysis experiments gave similar kinetic traces in near-UV and IR region. This suggests the presence of an interband level, that is, a polaron level occupied by an excess electron or a hole. (author)

  17. Laser-driven hydrothermal process studied with excimer laser pulses

    Science.gov (United States)

    Mariella, Raymond; Rubenchik, Alexander; Fong, Erika; Norton, Mary; Hollingsworth, William; Clarkson, James; Johnsen, Howard; Osborn, David L.

    2017-08-01

    Previously, we discovered [Mariella et al., J. Appl. Phys. 114, 014904 (2013)] that modest-fluence/modest-intensity 351-nm laser pulses, with insufficient fluence/intensity to ablate rock, mineral, or concrete samples via surface vaporization, still removed the surface material from water-submerged target samples with confinement of the removed material, and then dispersed at least some of the removed material into the water as a long-lived suspension of nanoparticles. We called this new process, which appears to include the generation of larger colorless particles, "laser-driven hydrothermal processing" (LDHP) [Mariella et al., J. Appl. Phys. 114, 014904 (2013)]. We, now, report that we have studied this process using 248-nm and 193-nm laser light on submerged concrete, quartzite, and obsidian, and, even though light at these wavelengths is more strongly absorbed than at 351 nm, we found that the overall efficiency of LDHP, in terms of the mass of the target removed per Joule of laser-pulse energy, is lower with 248-nm and 193-nm laser pulses than with 351-nm laser pulses. Given that stronger absorption creates higher peak surface temperatures for comparable laser fluence and intensity, it was surprising to observe reduced efficiencies for material removal. We also measured the nascent particle-size distributions that LDHP creates in the submerging water and found that they do not display the long tail towards larger particle sizes that we had observed when there had been a multi-week delay between experiments and the date of measuring the size distributions. This is consistent with transient dissolution of the solid surface, followed by diffusion-limited kinetics of nucleation and growth of particles from the resulting thin layer of supersaturated solution at the sample surface.

  18. 5 MW pulsed spallation neutron source, Preconceptual design study

    Energy Technology Data Exchange (ETDEWEB)

    1994-06-01

    This report describes a self-consistent base line design for a 5 MW Pulsed Spallation Neutron Source (PSNS). It is intended to establish feasibility of design and as a basis for further expanded and detailed studies. It may also serve as a basis for establishing project cost (30% accuracy) in order to intercompare competing designs for a PSNS not only on the basis of technical feasibility and technical merit but also on the basis of projected total cost. The accelerator design considered here is based on the objective of a pulsed neutron source obtained by means of a pulsed proton beam with average beam power of 5 MW, in {approx} 1 {mu}sec pulses, operating at a repetition rate of 60 Hz. Two target stations are incorporated in the basic facility: one for operation at 10 Hz for long-wavelength instruments, and one operating at 50 Hz for instruments utilizing thermal neutrons. The design approach for the proton accelerator is to use a low energy linear accelerator (at 0.6 GeV), operating at 60 Hz, in tandem with two fast cycling booster synchrotrons (at 3.6 GeV), operating at 30 Hz. It is assumed here that considerations of cost and overall system reliability may favor the present design approach over the alternative approach pursued elsewhere, whereby use is made of a high energy linear accelerator in conjunction with a dc accumulation ring. With the knowledge that this alternative design is under active development, it was deliberately decided to favor here the low energy linac-fast cycling booster approach. Clearly, the present design, as developed here, must be carried to the full conceptual design stage in order to facilitate a meaningful technology and cost comparison with alternative designs.

  19. 5 MW pulsed spallation neutron source, Preconceptual design study

    International Nuclear Information System (INIS)

    1994-06-01

    This report describes a self-consistent base line design for a 5 MW Pulsed Spallation Neutron Source (PSNS). It is intended to establish feasibility of design and as a basis for further expanded and detailed studies. It may also serve as a basis for establishing project cost (30% accuracy) in order to intercompare competing designs for a PSNS not only on the basis of technical feasibility and technical merit but also on the basis of projected total cost. The accelerator design considered here is based on the objective of a pulsed neutron source obtained by means of a pulsed proton beam with average beam power of 5 MW, in ∼ 1 μsec pulses, operating at a repetition rate of 60 Hz. Two target stations are incorporated in the basic facility: one for operation at 10 Hz for long-wavelength instruments, and one operating at 50 Hz for instruments utilizing thermal neutrons. The design approach for the proton accelerator is to use a low energy linear accelerator (at 0.6 GeV), operating at 60 Hz, in tandem with two fast cycling booster synchrotrons (at 3.6 GeV), operating at 30 Hz. It is assumed here that considerations of cost and overall system reliability may favor the present design approach over the alternative approach pursued elsewhere, whereby use is made of a high energy linear accelerator in conjunction with a dc accumulation ring. With the knowledge that this alternative design is under active development, it was deliberately decided to favor here the low energy linac-fast cycling booster approach. Clearly, the present design, as developed here, must be carried to the full conceptual design stage in order to facilitate a meaningful technology and cost comparison with alternative designs

  20. ENDOR determination of the proton positions around Gd3+ in La(C2H5SO4)3.9H2O

    International Nuclear Information System (INIS)

    Beer, R. de; Biesboer, F.; Ormondt, D. van

    1976-01-01

    The water proton positions around Gd 3+ in La(C 2 H 5 SO 4 ) 3 .9H 2 O have been determined by means of ENDOR. The positions of the nearest neighbour water oxygens are discussed on the basis of a superposition model analysis of the ratios b 2 0 /A 2 0 2 >, b 6 6 /b 6 0 and mod(A 6 6 )modA 6 0 . (Auth.)

  1. Pulse radiolysis in model studies toward radiation processing

    Energy Technology Data Exchange (ETDEWEB)

    Sonntag, C Von; Bothe, E; Ulanski, P; Deeble, D J [Max-Planck-Institut fuer Strahlenchemie, Muelheim an der Ruhr (Germany)

    1995-10-01

    Using the pulse radiolysis technique, the OH-radical-induced reactions of poly(vinyl alcohol) PVAL, poly(acrylic acid) PAA, poly(methyacrylic acid) PMA, and hyaluronic acid have been investigated in dilute aqueos solution. The reactions of the free-radical intermediates were followed by UV-spectroscopy and low-angle laser light-scattering; the scission of the charged polymers was also monitored by conductometry. For more detailed product studies, model systems such as 2,4-dihydroxypentane (for PVAL) and 2,4-dimethyl glutaric acid (for PAA) was also investigated. (author).

  2. One-electron oxidations of ferrocenes: a pulse radiolysis study

    International Nuclear Information System (INIS)

    Faraggi, Moshe; Weinraub, Dany; Broitman, Federico; DeFelippis, M.R.; Klapper, M.H.

    1988-01-01

    Using the pulse radiolysis technique we have studied the oxidation by various inorganic radicals of four water soluble ferrocene derivatives, hydroxyethyl, dimethylaminomethyl, monocarboxylic acid and dicarboxylic acid. We report the second order rate constants for these reactions, the stabilities and spectral properties of the ferrocinium products, and the electrochemically determined ferrocinium/ferrocene redox potentials. We also present preliminary estimates of tyrosine and tryptophan radical redox potentials obtained with the dicarboxylic acid ferrocene derivative as reference, and we discuss the relationship between redox potential differences and the reactivities of the ferrocenes with the inorganic radicals. (author)

  3. Free radical reactions of hematoporphyrin: a pulse radiolysis study

    International Nuclear Information System (INIS)

    Ahmed, Mohammed; Guleria, Apurav; Singh, Ajay K.; Sarkar, S.K.

    2011-01-01

    Radiation chemistry of porphyrin derivatives has been given much attention in recent years. Although till date photo dynamic therapy (PDT) with Hematoporphyrin (HP) has already proved its effectiveness in the treatment of cancer, the molecular mechanisms by which this therapy-destroys tumour cells as well as its optimal physical parameters are still not fully understood. Thus it becomes necessary to understand the interaction of different free radicals with HP. Pulse radiolysis studies have been performed to understand the interaction of different free radicals with HP. The product formation along with bleaching and presence of a number of transients makes it difficult to pin point the mode and site of free radical attack. The radiation-induced formation of various transients (HP-OH, HO - , HP + ) in aqueous solution was investigated at various pHs by pulse radiolysis technique by means of N 3 , O - and CCl 3 O 2 radicals with and without triethyl-amine, under different dose conditions. The observed intermediates are characterized by their kinetic and spectroscopic data. The absorption spectrum of each transient could be differentiated from each other by their absorption maxima, extinction coefficients and kinetics. A clear indication of product formation has also been observed by employing continuous electron pulse and the solution shows a green coloration. It is conceivable that under certain conditions, similar transients may be produced when HP is used as a sensitizer in radiation chemotherapy of cancer patients. Our study may throw some light into the breakdown mechanism of haemoglobin to BV in addition to the understanding of free radical interaction of HP. (author)

  4. Studying the mechanism of micromachining by short pulsed laser

    Science.gov (United States)

    Gadag, Shiva

    economical, because the micromachining rates are much higher than in the case of the ultra-short pulsed lasers. Hence, studying the mechanisms of micromachining by nanosecond pulsed laser of semiconductor silicon, transparent dielectric glass and quartz is undertaken for this research work. Laser drilling of an array of miniaturized micro holes is termed as laser micro via. A study of the effect of laser wavelengths, frequency, and energy of the pulses on the depth and diameter of craters and micro via are carried out using high resolution optical microscopy and a nano via 3D profiler. Analytical equations correlating depth and volume of the crater in terms of the optical absorption coefficient and ratio of peak applied to the threshold fluence for ablation of the silicon are derived. The depth of crater is scaled in terms of optical penetration depth times the ratio of crater diameter to the beam diameter. The shorter UV wavelengths are found to be more suitable for ablation of Si and SiO2 than longer IR wavelengths from the study of the absorption coefficient of Si varying with wavelength. Hence, the UV lasers (266 nm or 355 nm) are used for micromachining of Si and SiO2 involving cutting, cleaning, drilling and dicing, micro-milling and texturing of submicron size vertically oriented silicon wires for photovoltaic applications. The high density vertical wires are useful to grab a greater density of solar energy to generate more environmentally-friendly green power. The laser drilling of micro via can be typically of two types: (1) percussion drilling using a stationary laser beam with single or multiple pulses of the laser or (2) trepanned drilling of micro via by the circular motion of laser. Numerical simulation of dynamic drilling of laser micro via of silicon is performed, using control volume (FV) Fluent code in a Cartesian co-ordinate system. Total enthalpy formulation is used to simulate the phase change taking place during the laser ablation process from melting

  5. Feasibility study of a 1-MW pulsed spallation source

    International Nuclear Information System (INIS)

    Cho, Y.; Chae, Y.C.; Crosbie, E.

    1995-01-01

    A feasibility study of a 1-MW pulsed spallation source based on a rapidly cycling proton synchrotron (RCS) has been completed. The facility consists of a 400-MeV HP - linac, a 30-Hz RCS that accelerates the 400-MeV beam to 2 GeV, and two neutron-generating target stations. The design time-averaged current of the accelerator system is 0.5 mA, or 1.04x1014 protons per pulse. The linac system consists of an H - ion source, a 2-MeV RFQ, a 70-MeV DTL and a 330-MeV CCL. Transverse phase space painting to achieve a Kapchinskij-Vladimirskij (K-V) distribution of the injected particles in the RCS is accomplished by charge exchange injection and programming of the closed orbit during injection. The synchrotron lattice uses FODO cells of ∼90 degrees phase advance. Dispersion-free straight sections are obtained by using a missing magnet scheme. Synchrotron magnets are powered by a dual-frequency resonant circuit that excites the magnets at a 20-Hz rate and de-excites them at a 60-Hz rate, resulting in an effective rate of 30 Hz, and reducing the required peak rf voltage by 1/3. A key feature, of the design of this accelerator system is that beam losses are from injection to extraction, reducing activation to levels consistent with hands-on maintenance. Details of the study are presented

  6. Hole transfer in DNA studied by pulse radiolysis

    International Nuclear Information System (INIS)

    Majima, T.; Kawai, K.; Takada, T.

    2003-01-01

    Attention has been paid to charge transfer in DNA with respect to oxidation damage of DNA and nano bio-devices such as DNA molecular wire. We report hole transfer in DNA during pulse radiolysis of molecule-conjugated DNA (M-DNA). Direct measurement of the charge transfer in DNA has never been reported due to the low extinction coefficient of nucleobase radical ions and to difficult definition of nucleobases. We have used M-DNA in which M radical cation has enough extinction coefficient and distinct absorption. Radical cation was generated in M-DNA during pulse radiolysis in water, and hole transfer through DNA was monitored by time-resolved transient absorption spectra of the radical cations. Hole was generated in Py-DNA by pulse radiolysis in water. Hole transfer to Py through DNA was monitored by transient absorption of Py'+ at 465 nm. The hole hopping rate (k) from G-region to Py was determined to be 104 s-1 which decreased with intervening A-T base-pairs between Py and G-region. We suppose that G(-H+)-radical and C(+H+) basepair can alive in DNA more than 100 us and that this long lifetime is responsible to the long-distance hole transfer. The dependence of k against the distance between the G-region and Py led to the slope of 0.3 Angstroms-1 which is due to multi-step k with the smaller distance dependence. On the other hand, beta = 0.6 Angstroms-1 was found for the single-step k in DNA. On the basis of pulse radiolytic studied on various molecule-conjugated DNA, we found that hole transfer between two chromophores (A and B)-conjugated DNA increased with decreasing the distance between A and B and was accelerated slightly with increasing the number of Gs of the bridge between A and B, and that k was modulated by the bridged base sequences. We also found that weak distance dependent hole transfer in DNA by adenine hopping mechanism

  7. A feasibility study on age-related factors of wrist pulse using principal component analysis.

    Science.gov (United States)

    Jang-Han Bae; Young Ju Jeon; Sanghun Lee; Jaeuk U Kim

    2016-08-01

    Various analysis methods for examining wrist pulse characteristics are needed for accurate pulse diagnosis. In this feasibility study, principal component analysis (PCA) was performed to observe age-related factors of wrist pulse from various analysis parameters. Forty subjects in the age group of 20s and 40s were participated, and their wrist pulse signal and respiration signal were acquired with the pulse tonometric device. After pre-processing of the signals, twenty analysis parameters which have been regarded as values reflecting pulse characteristics were calculated and PCA was performed. As a results, we could reduce complex parameters to lower dimension and age-related factors of wrist pulse were observed by combining-new analysis parameter derived from PCA. These results demonstrate that PCA can be useful tool for analyzing wrist pulse signal.

  8. Numerical study of free pulsed jet flow with variable density

    Energy Technology Data Exchange (ETDEWEB)

    Kriaa, Wassim [Laboratoire de Mecanique des Fluides et Thermique, Ecole Nationale d' Ingenieurs de Monastir, Route de Ouardanine, 5000 Monastir (Tunisia)], E-mail: kriaawass@yahoo.fr; Cheikh, Habib Ben; Mhiri, Hatem [Laboratoire de Mecanique des Fluides et Thermique, Ecole Nationale d' Ingenieurs de Monastir, Route de Ouardanine, 5000 Monastir (Tunisia); Le Palec, Georges; Bournot, Philippe [Institut de Mecanique de Marseille, 60 rue Juliot Curie Technopole de Chateau-Gombert 13453, Marseille Cedex 13 (France)

    2008-05-15

    In this work, we propose a numerical study of a free pulsed plane jet with variable density in unsteady and laminar modes. At the nozzle exit, the flow is characterized by a uniform temperature and submitted to a longitudinal and periodic velocity disturbance: u = u{sub 0}(1 + A sin({omega}t)). A finite difference method is performed to solve the equations governing this flow type. The discussion relates to the effect of the most significant parameters, such as the pulsation frequency and amplitude, on the flow characteristic fields. The effects of Reynolds and Galileo numbers was also examined. The results show that the pulsation affects the flow in the vicinity of the nozzle, and further, the results of the unsteady mode join those of the steady non-pulsed jet. The results state also that the Strouhal number has no influence on the flow mixture degree, whereas the amplitude of pulsation affects, in a remarkable way, the mixture and, consequently, the concentration core length.

  9. Pulse shape discrimination studies of Phase I Ge-detectors

    Energy Technology Data Exchange (ETDEWEB)

    Kirsch, Andrea [MPI fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Collaboration: GERDA-Collaboration

    2013-07-01

    The GERmanium Detector Array experiment aims to search for the neutrinoless double beta decay (0νββ) of {sup 76}Ge by using isotopically enriched germanium crystals as source and detector simultaneously. The bare semiconductor diodes are operated in liquid argon at cryogenic temperatures in an ultra-low background environment. In addition, Gerda applies different active background reduction techniques, one of which is pulse shape discrimination studies of the current Phase I germanium detectors. The analysis of the signal time structure provides an important tool to distinguish single site events (SSE) of the ββ-decay from multi site events (MSE) of common gamma-ray background or surface events. To investigate the correlation between the signal shape and the interaction position, a new, also to the predominantly deployed closed-ended coaxial HPGe detectors applicable analysis technique has been developed. A summary of the used electronic/detector assembly is given and followed by a discussion of the performed classification procedure by means of accurate pulse shape simulations of 0νββ-like signals. Finally, the obtained results are presented along with an evaluation of the relevance for the Gerda experiment.

  10. Study on pulsed current cathodic protection in a simulated system

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Milin; Li, Helin [Xi' an Jiao Tong Universitiy (China)]|[Tubular Goods Research Center of China National Petroleum Corp. (China); Qiu, Yubing; Guo, Xingpeng [Hua Zhong University of Science and Techonology (China)

    2004-07-01

    The pulsed current cathodic protection (PCCP) is a new cathodic protection (CP) technology and shows more advantages over the conventional DC cathodic protection (DCCP) in oil well casing system. However, little information about PCCP is reported. In this research, a simulated CP system was set up in a pool of 3.5 m x 2.0 m x 3.0 m size, in which the effects of the square wave pulsed current (SWPC) parameters (amplitude: IA, frequency: f, duty cycle: P), auxiliary anode distance (d) and media conductivity ({mu}) on the cathodic potential (E) distribution were studied, and the protection effects of PCCP and DCCP were compared. The results show that with increase of the square wave parameters (IA, f, P), the E distribution becomes more negative and the effects of each current parameter are relate closely to the cathode polarizing state. Only with suitable square wave parameters can the whole cathode be effectively protected. With increase of d and {mu}, the E distribution becomes more uniform. Compared with DCCP system, PCCP system has much more uniform E distribution, costs less average current, and gains much better protection effects. Further, the mechanism of PCCP was analyzed. (authors)

  11. EPR and ENDOR Studies of Point Defects in Lithium Tetraborate Crystals

    Science.gov (United States)

    2012-12-14

    the US and its allies. Terrorist groups have shown interest in seeking and deploying weapons of mass destruction and mass disruption--weapons that...5]. Lithium tetraborate, has been grown pure and doped with many different elements including transition metals, actinides , and rare earth...microwave cavity is said to be “ critically coupled” when there is no reflected microwave power. Absorption of microwaves, which occurs when the magnetic

  12. A comparative study of pulsed dye laser versus long pulsed Nd:YAG laser treatment in recalcitrant viral warts.

    Science.gov (United States)

    Shin, Yo Sup; Cho, Eun Byul; Park, Eun Joo; Kim, Kwang Ho; Kim, Kwang Joong

    2017-08-01

    Viral warts are common infectious skin disease induced by human papillomavirus (HPV). But the treatment of recalcitrant warts is still challenging. In this study, we compared the effectiveness of pulsed dye laser (PDL) and long pulsed Nd:YAG (LPNY) laser in the treatment of recalcitrant viral warts. We retrospectively analyzed the medical records of patients with recalcitrant warts treated with laser therapy between January 2013 and February 2016. Seventy-two patients with recalcitrant warts were evaluated. Thirty-nine patients were treated with pulsed dye laser and thirty-three patients were treated with LPNY laser. The following parameters were used: PDL (spot size, 7 mm; pulse duration, 1.5 ms; and fluence, 10-14 J/cm 2 ) and LPNY (spot size, 5 mm; pulse duration, 20 ms; and fluence, 240-300 J/cm 2 ). Complete clearance of two patients (5.1%) in PDL group, and three patients (9.1%) in LPNY group were observed without significant side effects. The patients who achieved at least 50% improvement from baseline were 20 (51.3%) in PDL and 22 (66.7%) in LPNY, respectively. This research is meaningful because we compared the effectiveness of the PDL and LPNY in the recalcitrant warts. Both PDL and LPNY laser could be used as a safe and alternative treatment for recalcitrant warts.

  13. Pulse radiolysis studies of proline-ninhydrin complex

    Energy Technology Data Exchange (ETDEWEB)

    Barik, A; Priyadarsini, K I [Radiation and Photochemistry Division, Behabha Atomic Research Centre, Trombay, Mumbai (India); Prabhakar, K R; Veerapur, V P; Unnikrishnan, M K [Department of Pharmacology, Manipal College of Pharmaceutical Sciences (India)

    2006-07-01

    Proline-Ninhydrin (PN) complex has earlier been reported by us to be an excellent free radical scavenger and also examined for in vitro and in vivo radioprotection. Here we present mechanism of reaction of PN complex with hydroxyl ({sup .}OH) radicals and other oxidants and compared the results with proline and ninhydrin independently. PN complex was prepared by mixing in 1:1 stoichiometric ratio of proline and ninhydrin in a ball mill at 40 degree C and purified by crystallisation. Parent absorption spectra of PN complex show peak at 300 nm and 304 nm with a ground state pK{sub a} of 9.3. The reaction of {sup .}OH radical and other one-electron oxidants were studied using 7 MeV electron pulses from LINAC and the dose determined by aerated KSCN dosimeter. {sup .}OH radical reaction with PN studied at pH 6.8 produced a transients having broad absorption band at 400 nm. The reaction of {sup .}OH with PN complex was found to be dependent on the pH of the solution, at pH > 8 the transient absorption band shifted to 360 nm. The pK{sub a} of the transient was measured by following these absorption changes with varying the pH from 2 to 11 to be 6.9. OH radical reactions with the organic substrates is non-selective in nature and in order to establish the nature of the transient absorption band, pulse radiolysis studied were carried out with specific one electron oxidants, SO{sub 4}{sup .-} radical and Cl{sub 2}{sup .-} radical, which showed the transient absorption band with maximum at 440 nm and 350 nm respectively, indicating that the reaction {sup .}OH with PN complex at pH 7 is not by oxidation but by addition reaction to the aromatic ring. The reaction of H atom with PN complex was carried out in presence of tert-butanol at pH 1. The transient showed similar spectrum as observed with reaction OH radical reaction. As the H atom proceeds through mostly abstraction reaction, the transient formed by H atom and OH radical at low pH produces H atom abstracted species of the

  14. Studies of exposure of rabbits to electromagnetic pulsed fields

    International Nuclear Information System (INIS)

    Cleary, S.F.; Nickless, F.; Liu, L.M.; Hoffman, R.

    1980-01-01

    Dutch rabbits were acutely exposed to electromagnetic pulsed (EMP) fields (pulse duration 0.4 mus, field strengths of 1--2 kV/cm and pulse repetition rates in the range of 10 to 38 Hz) for periods of up to two hours. The dependent variables investigated were pentobarbital-induced sleeping time and serum chemistry (including serum triglycerides, creatine phosphokinase (CPK) isoenzymes, and sodium and potassium). Core temperature measured immediately pre-exposure and postexposure revealed no exposure-related alterations. Over the range of field strengths and pulse durations investigated no consistent, statistically significant alterations were found in the end-points investigated

  15. Theoretical study on device efficiency of pulsed liquid jet pump

    International Nuclear Information System (INIS)

    Gao Chuanchang; Lu Hongqi; Wang Shicheng; Cheng Mingchuan

    2001-01-01

    The influence of the main factors on device efficiency of pulsed liquid jet pump with gas-liquid piston is analysed, the theoretical equation and its time-averaged solution of pulsed liquid jet pump device efficiency are derived. The theoretical and experimental results show that the efficiency of transmission of energy and mass to use pulsed jet is greatly raised, compared with steady jet, in the same device of liquid jet pump. The calculating results of time-averaged efficiency of pulsed liquid jet pump are approximately in agreement with the experimental results in our and foreign countries

  16. Experimental study and modelisation of a pulse tube refrigerator

    International Nuclear Information System (INIS)

    Ravex, A.; Rolland, P.; Liang, J.

    1992-01-01

    A test bench for pulse tube refrigerator characterization has been built. In various configurations (basic pulse tube, orifice pulse tube and double inlet pulse tube), the ultimate temperature and the cooling power have been measured as a function of pressure wave amplitude and frequency for various geometries. A lowest temperature of 28 K has been achieved in a single staged double inlet configuration. A modelisation taking into account wall heat pumping, enthalpy flow and regenerator inefficiency is under development. Preliminary calculation results are compared with experimental data

  17. Hyperfine interaction studies with pulsed heavy-ion beams

    International Nuclear Information System (INIS)

    Raghavan, P.

    1985-01-01

    Heavy-ion reactions using pulsed beams have had a strong impact on the study of hyperfine interactions. Unique advantages offered by this technique have considerably extended the scope, detail and systematic range of its applications beyond that possible with radioactivity or light-ion reaction. This survey will cover a brief description of the methodological aspects of the field and recent applications to selected problems in nuclear and solid state physiscs illustrating its role. These include measurements of nuclear magnetic and electric quadrupole moments of high spin isomers, measurements of hyperfine magnetic fields at impurities in 3d and rare-earths ferromagnetic hosts, studies of paramagnetic systems, especially those exhibiting valence instabilities, and investigations of electric field gradients of impurities in noncubic metals. Future prospects of this technique will be briefly assessed. (orig.)

  18. An Experimental Study of a Pulsed Electromagnetic Plasma Accelerator

    Science.gov (United States)

    Thio, Y. C. Francis; Eskridge, Richard; Lee, Mike; Smith, James; Martin, Adam; Markusic, Tom E.; Cassibry, Jason T.; Rodgers, Stephen L. (Technical Monitor)

    2002-01-01

    Experiments are being performed on the NASA Marshall Space Flight Center (MSFC) pulsed electromagnetic plasma accelerator (PEPA-0). Data produced from the experiments provide an opportunity to further understand the plasma dynamics in these thrusters via detailed computational modeling. The detailed and accurate understanding of the plasma dynamics in these devices holds the key towards extending their capabilities in a number of applications, including their applications as high power (greater than 1 MW) thrusters, and their use for producing high-velocity, uniform plasma jets for experimental purposes. For this study, the 2-D MHD modeling code, MACH2, is used to provide detailed interpretation of the experimental data. At the same time, a 0-D physics model of the plasma initial phase is developed to guide our 2-D modeling studies.

  19. Pulse radiolysis studies of iron(I) in aqueous solutions

    International Nuclear Information System (INIS)

    Nenadovic, M.T.; Micic, O.I.; Muk, A.A.

    1980-01-01

    The absorption spectrum and decay kinetics of the products of the reactions of iron(II) ions with hydrated electrons and hydrogen atoms have been studied in aqueous solution using pulse-radiolysis techniques. Iron(I) is formed by reaction with hydrated electrons and its absorption spectrum is reported and discussed. The formation of molecular hydrogen by reaction of Fe + with water is suppressed by other solutes present in the solutions. In acidic solutions containing [SO 4 ] 2- , the intermediates formed in the reaction with H atoms decay by a first-order process and produce molecular hydrogen, but the rate of their decay does not depend only on the oxonium ion concentration but also on intermolecular rearrangement in the [FeSO 4 -H] complex. (author)

  20. CENTER FOR PULSED POWER DRIVEN HIGH ENERGY DENSITY PLASMA STUDIES

    Energy Technology Data Exchange (ETDEWEB)

    Professor Bruce R. Kusse; Professor David A. Hammer

    2007-04-18

    This annual report summarizes the activities of the Cornell Center for Pulsed-Power-Driven High-Energy-Density Plasma Studies, for the 12-month period October 1, 2005-September 30, 2006. This period corresponds to the first year of the two-year extension (awarded in October, 2005) to the original 3-year NNSA/DOE Cooperative Agreement with Cornell, DE-FC03-02NA00057. As such, the period covered in this report also corresponds to the fourth year of the (now) 5-year term of the Cooperative Agreement. The participants, in addition to Cornell University, include Imperial College, London (IC), the University of Nevada, Reno (UNR), the University of Rochester (UR), the Weizmann Institute of Science (WSI), and the P.N. Lebedev Physical Institute (LPI), Moscow. A listing of all faculty, technical staff and students, both graduate and undergraduate, who participated in Center research activities during the year in question is given in Appendix A.

  1. Pulsed laser photoacoustic spectrometer for study of solid materials

    International Nuclear Information System (INIS)

    Patel, N.D.; Kartha, V.B.

    1991-01-01

    The technique of photoacoustic spectroscopy has wide applications bacause it is extremely sensitive, and can be used to obtain spectra in wide spectral range for solids, liquids, gases, solutions, crystals etc. which may be usually difficult by conventional methods. For studying a variety of materials, a pulsed laser photoacoustic spectrometer has been set up in the laboratory. The report discusses the design and performance of the instrument. Some of the spectra of materials like Nd 2 O 9 powder, Nd-YAG crystal, CoCl 2 6H 2 O etc. are shown. A detailed discussion on assignment of the spectra of Nd-YAG is also presented. (author). 4 refs., 5 figs., 1 tab

  2. Mechanical study of 20 MJ superconducting pulse coil

    International Nuclear Information System (INIS)

    Hattori, Yasuhide; Shimamoto, Susumu

    1985-09-01

    This paper describes calculation methods and computer codes of stress distribution in a circular-shaped superconducting pulsed coils. The stress problems of a large sized superconducting coil, for example, are discussed for 20 MJ pool-cooled pulse coil. Young's modulus of a stranded flat cable, low rigidity, is measured and evaluated. (author)

  3. Pulsed Electromagnetic Field Assisted in vitro Electroporation: A Pilot Study

    Science.gov (United States)

    Novickij, Vitalij; Grainys, Audrius; Lastauskienė, Eglė; Kananavičiūtė, Rūta; Pamedytytė, Dovilė; Kalėdienė, Lilija; Novickij, Jurij; Miklavčič, Damijan

    2016-09-01

    Electroporation is a phenomenon occurring due to exposure of cells to Pulsed Electric Fields (PEF) which leads to increase of membrane permeability. Electroporation is used in medicine, biotechnology, and food processing. Recently, as an alternative to electroporation by PEF, Pulsed ElectroMagnetic Fields (PEMF) application causing similar biological effects was suggested. Since induced electric field in PEMF however is 2-3 magnitudes lower than in PEF electroporation, the membrane permeabilization mechanism remains hypothetical. We have designed pilot experiments where Saccharomyces cerevisiae and Candida lusitaniae cells were subjected to single 100-250 μs electrical pulse of 800 V with and without concomitant delivery of magnetic pulse (3, 6 and 9 T). As expected, after the PEF pulses only the number of Propidium Iodide (PI) fluorescent cells has increased, indicative of membrane permeabilization. We further show that single sub-millisecond magnetic field pulse did not cause detectable poration of yeast. Concomitant exposure of cells to pulsed electric (PEF) and magnetic field (PMF) however resulted in the increased number PI fluorescent cells and reduced viability. Our results show increased membrane permeability by PEF when combined with magnetic field pulse, which can explain electroporation at considerably lower electric field strengths induced by PEMF compared to classical electroporation.

  4. Pulse radiolysis studies on DNA-Binding radioprotectors

    International Nuclear Information System (INIS)

    Anderson, R.F.

    1996-01-01

    Full text: Hoechst 33342 and newly-synthesised analogues exhibit radioprotective activity in cultured cells and in vivo, as described in accompanying abstracts. These minor groove binding ligands bind at discreet sites in DNA, characterised by 3 to 4 consecutive AT base pairs, and DNA sequencing studies have shown focussed radioprotection at these binding sites. There is evidence that the bound ligands also confer more 'global' protection including the intervening DNA between the binding sites. The observed focussed radioprotection could be explained by H-atom donation from the ligand to radiation-induced carbon-centred deoxyribosyl radicals, but this mechanism is unlikely to account for the global radioprotection. We now report pulse radiolysis studies on another possible mechanism, namely reduction of transient radiation-induced oxidising species on DNA by the ligand, which is consistent with the report of reduction of G + by TMPD. Oxidation of deoxyguanosine (dG) by Br 2 - , produced by radiolysis of Br- in N 2 0-saturated solutions, in the presence of Hoechst 33342 results in the appearance of a transient ligand species which is kinetically resolvable from that obtained from direct oxidation of Hoechst 33342 by Br 2 - . A plot of reaction rate versus ligand concentration indicates that the rate constant for reduction of G + is approximately 3 x 10 8 dm 3 M -1 sec -1 . Similar experiments with DNA, rather than dG, also revealed a transient species corresponding to oxidation of the ligand, but the absolute rate of oxidation was considerably slower for the DNA-bound ligand compared to that for oxidation of the free ligand by G+. These results are clearly consistent with the proposed mechanism of radioprotection by Hoechst 33342 and its analogues, moreover, pulse radiolysis may provide a very useful endpoint for screening new analogues, as a preliminary to radiobiological evaluation

  5. Study of general digital DC/pulse neutron generator

    International Nuclear Information System (INIS)

    Li Gang; Liu Zheng; Li Wensheng; Liu Hanlin; Liu Linmao

    2014-01-01

    Preliminary experimental results of digital DC/pulse neutron generator based on a ceramic drive-in target neutron tube for explosives detection are presented. The generator is a portable and on-off neutron source, and it can be controlled by remote PC. The generator can produce DC neutrons, pulse neutrons and multiple pulse neutrons. The maximum neutron yield is about 2 × 10"8 n/s, the minimum pulse width is 10 μs and the maximum pulse frequency is 10 kHz. Neutron yield and time-spectrum is measured in China Academy of Engineering Physics. The generator is suitable for explosive detection with PFTNA technology, and it can be used in other areas such as reactor measurements and on-line industrial test systems. (authors)

  6. Picosecond pulse radiolysis study of primary reactions in solutions

    International Nuclear Information System (INIS)

    El-Omar, Abdel Karim

    2013-01-01

    Following the discovery of ionizing radiations and their chemical effects, it was important to study and comprehend the formation mechanisms of short lived free radicals and molecular products. In order to perform such studies, researchers and research groups worked on developing tools allowing both formation and detection of those species at short time scales. Nowadays, pulse radiolysis imposed itself as a fundamental and efficient tool allowing scientists to probe chemical effects as well as reaction mechanisms in studied media. The Laboratoire de Chimie Physique d'Orsay 'LCP' is an interdisciplinary laboratory hosting the platform of fast kinetics known as 'ELYSE'. Due to its femtosecond laser and its picosecond electron accelerator, we have the possibility to study chemical effects of ionizing radiations interaction with media at ultrashort times up to ∼5 ps.Knowing that we are interested in primary reactions induced in aqueous media by ionizing radiations, ELYSE represents the essential tool in performing our studies. The obtained results concern:- First direct determination of hydroxyl radical 'HO*' radiolytic yield as function of time at picosecond time scale;- Direct effect of ionizing radiation in highly concentrated aqueous solutions as well as investigation of the ultrafast electron transfer reaction between solute molecules and positive holes 'H 2 O*+' formed upon water radiolysis;- Study at room temperature of electron transfer reaction between solvated electron (electron donor) and organic solutes (electron acceptors) en viscous medium;- Study at room temperature of electron's solvation dynamics in ethylene glycol and 2-propanol. (author)

  7. Hydroxyapatite thin films grown by pulsed laser deposition and matrix assisted pulsed laser evaporation: Comparative study

    Science.gov (United States)

    Popescu-Pelin, G.; Sima, F.; Sima, L. E.; Mihailescu, C. N.; Luculescu, C.; Iordache, I.; Socol, M.; Socol, G.; Mihailescu, I. N.

    2017-10-01

    Pulsed Laser Deposition (PLD) and Matrix Assisted Pulsed Laser Evaporation (MAPLE) techniques were applied for growing hydroxyapatite (HA) thin films on titanium substrates. All experiments were conducted in a reaction chamber using a KrF* excimer laser source (λ = 248 nm, τFWHM ≈ 25 ns). Half of the samples were post-deposition thermally treated at 500 °C in a flux of water vapours in order to restore crystallinity and improve adherence. Coating surface morphologies and topographies specific to the deposition method were evidenced by scanning electron, atomic force microscopy investigations and profilometry. They were shown to depend on deposition technique and also on the post-deposition treatment. Crystalline structure of the coatings evaluated by X-ray diffraction was improved after thermal treatment. Biocompatibility of coatings, cellular adhesion, proliferation and differentiation tests were conducted using human mesenchymal stem cells (MSCs). Results showed that annealed MAPLE deposited HA coatings were supporting MSCs proliferation, while annealed PLD obtained films were stimulating osteogenic differentiation.

  8. Study of growth mechanism of conducting polymers by pulse radiolysis

    International Nuclear Information System (INIS)

    Coletta, Cecilia

    2016-01-01

    Today conductive polymers have many applications in several devices. For these reasons they have received much attention in recent years. Despite intensive research, the mechanism of conducting polymers growth is still poorly understood and the methods of polymerization are limited to two principal ways: chemical and electrochemical synthesis. On the other hand, the complex properties of polymers can be controlled only if a good knowledge of polymerization process is acquired. In this case, it is possible to control the process during the synthesis (functionalization, hydrophilicity, chain length, doping level), and consequently to improve the conductive properties of the synthesized polymers. Water radiolysis represents an easy and efficient method of synthesis comparing to chemical and electrochemical polymerization routes. It enables the polymerization under soft conditions: ambient temperature and pressure, without any external dopant. Among all conductive polymers, poly(3, 4-ethylenedioxy-thiophene) (PEDOT, a derivative of poly-thiophene) and poly-Pyrrole (PPy) have gained some large scale applications for their chemical and physical proprieties. The aim of the present work was the synthesis of PEDOT and PPy in aqueous solution and the study of their growth mechanism by pulsed radiolysis. Thanks to the electron accelerator ELYSE, the use of pulsed radiolysis coupled with time-resolved absorption spectroscopy allowed to study the kinetics of polymerization. The first transient species involved in the mechanism were identified by time resolved spectroscopy and the rate constants were determined. First, the reaction of hydroxyl radicals onto EDOT and Py monomers was studied, as well as the corresponding radiation induced polymerization. Then, the study was transposed to others oxidizing radicals such as CO3 .- , N 3 . and SO 4 .- at different pHs. This approach allowed to check and to highlight the influence of oxidizing species onto the first transient species

  9. S-process studies using single and pulsed neutron exposures

    Science.gov (United States)

    Beer, H.

    The formation of heavy elements by slow neutron capture (s-process) is investigated. A pulsed neutron irradiation leading to an exponential exposure distribution is dominant for nuclei from A = 90 to 200. For the isotopes from iron to zirconium an additional 'weak' s-process component must be superimposed. Calculations using a single or another pulsed neutron exposure for this component have been carried out in order to reproduce the abundance pattern of the s-only and s-process dominant isotopes. For the adjustment of these calculations to the empirical values, the inclusion of new capture cross section data on Se76 and Y89 and the consideration of the branchings at Ni63, Se79, and Kr85 was important. The combination of an s-process with a single and a pulsed neutron exposure yielded a better representation of empirical abundances than a two component pulsed s-process.

  10. S-process studies using single and pulsed neutron exposures

    International Nuclear Information System (INIS)

    Beer, H.

    1986-01-01

    The formation of heavy elements by slow neutron capture (s-process) is investigated. A pulsed neutron irradiation leading to an exponential exposure distribution is dominant for nuclei from A=90 to 200. For the isotopes from iron to zirconium an additional ''weak'' s-process component must be superimposed. Calculations using a single or another pulsed neutron exposure for this component have been carried out in order to reproduce the abundance pattern of the s-only and s-process dominant isotopes. For the adjustment of these calculations to the empirical values, including new capture cross section data on Se76 and Y89 and the consideration of the branchings at Ni63, Se79, and Kr85 was important. The combination of a s-process with a single and a pulsed neutron exposure yielded a better representation of empirical abundances than a two component pulsed s-process

  11. Fundamental study on metal plating removal using pulsed power technology

    International Nuclear Information System (INIS)

    Imasaka, Kiminobu; Gnapowski, Sebastian; Akiyama, Hidenori

    2013-01-01

    A novel method for the metal removal from metal-plated substrate using pulsed power technology is proposed. A metal-plated substrate with three metal-layers structure (Cu, Ni and Au) is used as the sample substrate. Repetitive pulsed arc discharge plasma is generated between a rod electrode and the surface of substrate. Effect of the type of electrode system on metal plating removal was investigated. The removal region is produced by the moving phenomena of the pulsed arc discharge. A part of Au layer, which is the tompost metal surface of the substrate is vaporized and removed by the repetitive pulsed arc discharges. The proposed method can be used for recycle of metal-plated substrate. (author)

  12. In-vivo studies of reflectance pulse oximeter sensor

    Science.gov (United States)

    Ling, Jian; Takatani, Setsuo; Noon, George P.; Nose, Yukihiko

    1993-08-01

    Reflectance oximetry can offer an advantage of being applicable to any portion of the body. However, the major problem of reflectance oximetry is low pulsatile signal level which prevents prolonged clinical application during extreme situations, such as hypothermia and vasoconstriction. In order to improve the pulsatile signal level of reflectance pulse oximeter and thus its accuracy, three different sensors, with the separation distances (SPD) between light emitting diode (LED) and photodiode being 3, 5, and 7 mm respectively, were studied on nine healthy volunteers. With the increase of the SPD, it was found that both the red (660 nm) and near-infrared (830 nm) pulsatile to average signal ratio (AC/DC) increased, and the standard deviations of (AC/DC)red/(AC/DC)infrared ratio decreased, in spite of the decrease of the absolute signal level. Further clinical studies of 3 mm and 7 mm SPD sensors on seven patients also showed that the (AC/DC)red/(AC/DC)infrared ratio measured by the 7 mm sensor were less disturbed than the 3 mm sensor during the surgery. A theoretical study based on the three-dimensional photon diffusion theory supports the experimental and clinical results. As a conclusion, the 7 mm sensor has the highest signal-to- noise ratio among three different sensors. A new 7 mm SPD reflectance sensor, with the increased number of LEDs around the photodiode, was designed to increase the AC/DC ratio, as well as to increase the absolute signal level.

  13. Pulsed field studies of magnetotransport in semiconductor heterostructures

    International Nuclear Information System (INIS)

    Dalton, K.S.H.

    1999-01-01

    High field magnetotransport in two classes of semiconductor heterostructures has been studied: parallel transport in InAs/(Ga,In)Sb double heterojunctions and superlattices at low temperatures (300 mK-4.2 K), and vertical transport in GaAs/AlAs short-period superlattices at 150-300 K. The experiments mainly used the Oxford pulsed magnet (∼45 T, ∼15 ms pulses). The development of the data acquisition system and experimental techniques for magnetotransport are described, including corrections to the data, required because of the rapidly changing magnetic field. Previous studies of magnetotransport in InAs/GaSb double heterojunctions are reviewed: this electron-hole system shows compensated quantum Hall plateaux, with ρ xy dips accompanied by 'anomalous' peaks in σ xx . New data show a peak between ν=1 plateaux; this behaviour and the temperature dependence of the 'anomalous' σ xx peaks are explained by considering the movement of the Fermi level amongst anticrossing electron- and hole-like levels. InAs/(Ga,In)Sb superlattices with electron:hole density ratios close to 1 exhibit large oscillations in the resistivity (maxima typically ∼20-30 x higher than minima) and conductivity components. Deep minima in ρ xy alternate with low-integer plateaux. The magnetotransport in various ideal structures is considered, to explain the experimental results. The growth of a novel structure has allowed clearer observation of the behaviour of ρ xx (giant maxima) and ρ xy (zeroes or maxima) when the contributions from each well to σ xx and σ xy approach zero. Measurements of the high field magnetotransport peak positions show that the band overlap is increased by growing 'InSb' rather than 'GaAs' interfaces (∼20% increase), increasing the indium in the (Ga,In)Sb (∼30% increase per 10% In), or growing along [111] instead of [001] (∼30% increase). Magnetophonon resonance in short-period GaAs/AlAs superlattices causes strong, electric field-dependent vertical

  14. Pulsed radiation studies of carotenoid radicals and excited states

    International Nuclear Information System (INIS)

    Burke, M.

    2001-04-01

    The one-electron reduction potentials of the radical cations of five dietary carotenoids, in aqueous micellar environments, have been obtained from a pulse radiolysis study of electron transfer between the carotenoids and tryptophan radical cations as a function of pH, and lie in the range 980 to 1060 mV. The decays of the carotenoid radical cations suggest a distribution of exponential lifetimes. The radicals persist for up to about one second, depending on the medium and may re-orientate within a biological environment to react with other biomolecules, such as tyrosine, cysteine or ascorbic acid, which was indeed confirmed. Spectral information of carotenoid pigmented liposomes has been collected, subsequently pulse radiolysis was used to generate the radical cations of β-carotene, zeaxanthin and lutein, in unilamellar vesicles of dipalmitoyl phosphatidyl choline. The rate constants for the 'repair' of these carotenoid radical cations by water-soluble vitamin C were found to be similar (∼1 x 10 7 M -1 s -1 ) for β-carotene and zeaxanthin and somewhat lower (∼0.5 x 10 7 M -1 s -1 ) for lutein. The results are discussed in terms of the microenvironment of the carotenoids and suggest that for β-carotene, a hydrocarbon carotenoid, the radical cation is able to interact with a water-soluble species even though the parent hydrocarbon carotenoid is probably entirely in the non-polar region of the liposome. Studies investigating the ability of ingested lycopene to protect human lymphoid cells against singlet oxygen and nitrogen dioxide radical mediated cell damage have shown that a high lycopene diet is beneficial in protecting human cells against reactive oxygen species. Triplet states of carotenoids were produced in benzene solvent and their triplet lifetimes were found to depend on the concentration of the parent molecule. The rate constants obtained for ground state quenching correlate with the number of conjugated double bonds, the longer chain systems having

  15. A study of pulse columns for thorium fuel reprocessing

    International Nuclear Information System (INIS)

    Fumoto, H.

    1982-03-01

    Two 5 m pulse columns with the same cartridge geometries are installed to investigate the performance. The characteristic differences of the aqueous continous and the organic continuous columns were investigated experimentally. A ternary system of 30% TBP in dodecane-acetic acid-water was adopted for the mass-transfer study. It was concluded that the overall mass-transfer coefficient was independent of whether the mass-transfer is from the dispersed to the continuous phase or from the continuous to the dispersed phase. Thorium nitrate was extracted and reextracted using both modes of operation. Both HETS and HTU were obtained. The aqueous continuous column gave much shorter HTU than the organic continuous column. In reextraction the organic continuous column gave shorter HTU. The Thorex-processes for uranium and thorium co-extraction, co-stripping, and partitioning were studied. Both acid feed solution and acid deficiend feed solution were investigated. The concentration profiles along the column height were obtained. The data were analysed with McCABE-THIELE diagrams to evaluate HETS. (orig./HP) [de

  16. Pulse radiolysis in model studies toward radiation processing

    Science.gov (United States)

    Von Sonntag, C.; Bothe, E.; Ulanski, P.; Deeble, D. J.

    1995-02-01

    Using the pulse radiolysis technique, the OH-radical-induced reactions of poly(vinyl alcohol) PVAL, poly(acrylic acid) PAA, poly(methacrylic acid) PMA, and hyaluronic acid have been investigated in dilute aqueous solution. The reactions of the free-radical intermediates were followed by UV-spectroscopy and low-angle laser light-scattering; the scission of the charged polymers was also monitored by conductometry. For more detailed product studies, model systems such as 2,4-dihydroxypentane (for PVAL) and 2,4-dimethyl glutaric acid (for PAA) was also investigated. With PVA, OH-radicals react predominantly by abstraction of an H-atom in α-position to the hydroxyl group (70%). The observed bimolecular decay rate constant of the PVAL-radicals decreases with time. This has been interpreted as being due to an initially fast decay of proximate radicals and a decrease of the probability of such encounters with time. Intramolecular crosslinking (loop formation) predominates at high doses per pulse. In the presence of O 2, peroxyl radicals are formed which in the case of the α-hydroxyperoxyl radicals can eliminate HO 2-radicals in competition with bimolecular decay processes which lead to a fragmentation of the polymer. In PAA, radicals both in α-position (characterized by an absorption near 300 nm) and in β-position to the carboxylate groups are formed in an approximately 1:2 ratio. The lifetime of the radicals increases with increasing electrolytic dissociation of the polymer. The β-radicals undergo a slow (intra- as well as intermolecular) H-abstraction yielding α-radicals, in competition to crosslinking and scission reactions. In PMA only β-radicals are formed. Their fragmentation has been followed by conductometry. In hyaluronic acid, considerable fragmeentation is observed even in the absence of oxygen which, in fact, has some protective effect against this process. Thus free-radical attack on this important biopolymer makes it especially vulnerable with respect

  17. Studies on gas breakdown in pulsed radio frequency atmospheric pressure glow discharges

    International Nuclear Information System (INIS)

    Huo, W. G.; Jian, S. J.; Yao, J.; Ding, Z. F.

    2014-01-01

    In pulsed RF atmospheric pressure glow discharges, the gas breakdown judged by the rapid drop in the amplitude of the pulsed RF voltage is no longer universally true. The steep increment of the plasma-absorbed RF power is proposed to determine the gas breakdown. The averaged plasma-absorbed RF power over a pulse period is used to evaluate effects of the preceding pulsed RF discharge on the breakdown voltage of the following one, finding that the breakdown voltage decreases with the increment in the averaged plasma-absorbed RF power under constant pulse duty ratio. Effects of the pulse off-time on the breakdown voltage and the breakdown delay time are also studied. The obtained dependence of the breakdown voltage on the pulse off-time is indicative of the transitional plasma diffusion processes in the afterglow. The breakdown voltage varies rapidly as the plasma diffuses fast in the region of moderate pulse off-time. The contribution of nitrogen atom recombination at the alumina surface is demonstrated in the prolonged memory effect on the breakdown delay time vs. the pulse off-time and experimentally validated by introducing a trace amount of nitrogen into argon at short and long pulse off-times

  18. Feasibility study of a contained pulsed nuclear propulsion engine

    International Nuclear Information System (INIS)

    Parlos, A.G.; Metzger, J.D.

    1994-01-01

    The result of a feasibility analysis of a contained pulsed nuclear propulsion (CPNP) engine concept utilizing the enormously dense energy generated by small nuclear detonations is presented in this article. This concept was initially proposed and studied in the 1950s and 1960s under the program name HELIOS. The current feasibility of the concept is based upon materials technology that has advanced to a state that allows the design of pressure vessels required to contain the blast associated with small nuclear detonations. The impulsive nature of the energy source provides the means for circumventing the materials thermal barriers that are inherent in steady-state nuclear propulsion concepts. The rapid energy transfer to the propellant results in high thrust levels for times less than 1 s following the detonation. The preliminary feasibility analysis using off-the-shelf materials technology appears to indicate that the CPNP concept can have thrust-to-weight ratios on the order of 1 or greater. Though the specific impulse is not a good indicator for impulsive engines, an operating-cycle averaged specific impulse of approximately 1000 or greater seconds was calculated. 16 refs

  19. Pulse EPR distance measurements to study multimers and multimerisation

    Science.gov (United States)

    Ackermann, Katrin; Bode, Bela E.

    2018-06-01

    Pulse dipolar electron paramagnetic resonance (PD-EPR) has become a powerful tool for structural biology determining distances on the nanometre scale. Recent advances in hardware, methodology, and data analysis have widened the scope to complex biological systems. PD-EPR can be applied to systems containing lowly populated conformers or displaying large intrinsic flexibility, making them all but intractable for cryo-electron microscopy and crystallography. Membrane protein applications are of particular interest due to the intrinsic difficulties for obtaining high-resolution structures of all relevant conformations. Many drug targets involved in critical cell functions are multimeric channels or transporters. Here, common approaches for introducing spin labels for PD-EPR cause the presence of more than two electron spins per multimeric complex. This requires careful experimental design to overcome detrimental multi-spin effects and to secure sufficient distance resolution in presence of multiple distances. In addition to obtaining mere distances, PD-EPR can also provide information on multimerisation degrees allowing to study binding equilibria and to determine dissociation constants.

  20. Long-pulsed Nd: YAG laser and intense pulse light-755 nm for idiopathic facial hirsutism: A comparative study

    Directory of Open Access Journals (Sweden)

    Arpit Shrimal

    2017-01-01

    Full Text Available Background: Hirsutism means excessive terminal hair growth in a female in male pattern distribution. Perception of hirsutism is subjective. Permanent laser hair reduction is a slow process taking many sessions and tracking of improvement parameters is tedious. Hence, a lot of confusion still exists regarding the type of laser most beneficial for treatment. Aim: The aim of this study was to compare the effectiveness and safety profile of long-pulsed Nd: YAG laser (1064 nm and intense pulse light (IPL-755 nm in management of idiopathic facial hirsutism. Settings and Design: Open-labelled, randomly allocated experimental study. Subjects and Methods: The study included 33 cases of idiopathic facial hirsutism. Patients were randomly divided into Group A, treated with long-pulsed Nd: YAG laser and Group B, treated with IPL-755 for a total of six sessions at 1 month interval. Statistical Analysis: Chi-square test was used in Medcalc® version 9.0 and the test of significance was taken to be P75% reduction in hair after six sessions in Group A was seen in fourteen (93.33% out of fifteen patients, whereas in Group B, it was seen only in three (16.66% out of eighteen patients. In Group A, erythema was seen in 26.67%, perifollicular edema and hyperpigmentation in 13.33% each. In Group B, erythema was seen in 50% patients, perifollicular edema in 16.67% and hyperpigmentation in 38.89% patients. Conclusions: Long-pulsed Nd: YAG Laser (1064 nm is better than IPL-755 nm in terms of safety and effectiveness in the management of idiopathic facial hirsutism.

  1. Pulse radiolysis for the study of lead salt solutions

    International Nuclear Information System (INIS)

    Breitenkamp, M.

    1976-01-01

    The Pb + ions are produced from Pb 2 + in lead perchlorate solutions by reduction with hydrated electrons, and the absorption spectrum of this ion has been measured together with a time differential observation in the micro- and millisecond range of the disparation of these ions from the solution in the presence of different substances. For these studies the method of pulsed radiolysis has been applied, detecting the short lifed intermediate reaction products by optical absorption and electric conductivity measurements. First an attempt has been made to produce the Pb + ions also by reduction of Pb 2 + with H-atoms. If Pb + and H is produced simultaneously in an aqueous solution the reaction Pb + + H -> PbH + can occur. The absorption spectrum of the short lifed species PbH + has been studied together with the second order evanescence. In addition Pb 2 + has been reduced by i-propanol radicals at high Pb 2 + concentrations. The second order evanescence has been observed and the rate constant of the reaction 2Pb + -> Pb + Pb 2 + has been measured. The Pb 2 + ions can also be reduced by CO 2- radicals, which are formed in the presence of formiate. The observations can be interpreted by the assumption of the primary reaction Pb 2 + + CO 2- -> PbCO 2+ . the spectrum of the product PbCO 2+ has been measured. A second order reaction of PbCO 2+ is observed with a resulting unstable particle of the structure Pb 2 CO 2 2 + . Finally the oxidation of Pb + by the OH-radical and by hydrogen peroxide has been studied. (orig./HK) [de

  2. Study of low vibration 4 K pulse tube cryocoolers

    Science.gov (United States)

    Xu, Mingyao; Nakano, Kyosuke; Saito, Motokazu; Takayama, Hirokazu; Tsuchiya, Akihiro; Maruyama, Hiroki

    2012-06-01

    Sumitomo Heavy Industries, Ltd. (SHI) has been continuously improving the efficiency and reducing the vibration of a 4 K pulse tube cryocooler. One advantage of a pulse tube cryocooler over a GM cryocooler is low vibration. In order to reduce vibration, both the displacement and the acceleration have to be reduced. The vibration acceleration can be reduced by splitting the valve unit from the cold head. One simple way to reduce vibration displacement is to increase the wall thickness of the tubes on the cylinder. However, heat conduction loss increases while the wall thickness increases. To overcome this dilemma, a novel concept, a tube with non-uniform wall thickness, is proposed. Theoretical analysis of this concept, and the measured vibration results of an SHI lowvibration pulse tube cryocooler, will be introduced in this paper.

  3. Pulsed Thermography Applied to the Study of Cultural Heritage

    Directory of Open Access Journals (Sweden)

    Fulvio Mercuri

    2017-09-01

    Full Text Available In this paper, an overview of the recent applications of pulsed infrared thermography is presented. Pulsed infrared thermography, which provides stratigraphic information by analyzing the heat diffusion process within the sample after a thermal perturbation, is applied to the investigation of different kinds of cultural heritage artefacts. In particular, it is used to analyze repairs, decorative elements, and casting faults on bronzes, to detect texts hidden or damaged in ancient books/documents, and to characterize paint decorations. Moreover, the integration of pulsed infrared thermography and three-dimensional shape recording methods is proposed in order to provide a three-dimensional representation of the thermographic results. Finally, it is shown how the obtained thermographic results may be crucial from the historical and artistic points of view for understanding the modus operandi of a specific artist and/or of a workshop and for reconstructing the manufacturing process of the analyzed artefacts.

  4. Preliminary Optical And Electric Field Pulse Statistics From Storm Overflights During The Altus Cumulus Electrification Study

    Science.gov (United States)

    Mach, D. A.; Blakeslee, R. J.; Bailey, J. C.; Farrell, W. M.; Goldberg, R. A.; Desch, M. D.; Houser, J. G.

    2003-01-01

    The Altus Cumulus Electrification Study (ACES) was conducted during the month of August, 2002 in an area near Key West, Florida. One of the goals of this uninhabited aerial vehicle (UAV) study was to collect high resolution optical pulse and electric field data from thunderstorms. During the month long campaign, we acquired 5294 lightning generated optical pulses with associated electric field changes. Most of these observations were made while close to the top of the storms. We found filtered mean and median 10-10% optical pulse widths of 875 and 830 microns respectively while the 50-50% mean and median optical pulse widths are 422 and 365 microns respectively. These values are similar to previous results as are the 10-90% mean and median rise times of 327 and 265 microns. The peak electrical to optical pulse delay mean and median were 209 and 145 microns which is longer than one would expect from theoretical results. The results of the pulse analysis will contribute to further validation of the Optical Transient Detector (OTD) and the Lightning Imaging Sensor (LIS) satellites. Pre-launch estimates of the flash detection efficiency were based on a small sample of optical pulse measurements associated with less than 350 lightning discharges collected by NASA U-2 aircraft in the early 1980s. Preliminary analyses of the ACES measurements show that we have greatly increased the number of optical pulses available for validation of the LIS and other orbital lightning optical sensors. Since the Altus was often close to the cloud tops, many of the optical pulses are from low-energy pulses. From these low-energy pulses, we can determine the fraction of optical lightning pulses below the thresholds of LIS, OTD, and any future satellite-based optical sensors such as the geostationary Lightning Mapping Sensor.

  5. Study of startup conditions of a pulsed annular reactor

    International Nuclear Information System (INIS)

    Silva, Mario Augusto Bezerra da

    2003-10-01

    A new concept of reactor, which combines features of pulsed and stationary reactors, was proposed so as to produce intense neutronic fluxes. Such a reactor, known as VICHFPR (Very Intense Continuous High Flux Pulsed Reactor), consists of a subcritical core with an annular geometry and pulsed by a rotating reflector which acts as a reactivity modulator as it produces a short pulse (approximately equal to 1 ms) of high intensity, guiding the region near the pulser to super-prompt critical state. This dissertation intends to analyze the startup conditions of a Pulsed Annular Reactor. The evolution of the neutron pulse intensity is analyzed when the reactivity modulator is brought upwards according to a helicoidal path from its initial position (far away from the core), when the multiplication factor has a subcritical value, up to the final position (near the core), in which a super-prompt critical state is reached. Part of the analysis is based on the variation of neutron reflection, which is a uniform function of the exit and reflection angles between the core and the modulator. It must be emphasized that this work is an approximation of the real situation. As the initial and final reactor parameters are known, a programming code in Fortran is worked out to provide the multiplication factor and the flux intensity evolution. According to the results obtained with this code, the conditions under which the modulator must be lifted up during the startup are established. Basically, these conditions are related to the analysis of the rising and the rotation velocities, the reflector saving and the initial distance between the reactor and the modulator. The Pulsed Annular Reactor startup was divided into three stages. Because of its negative reactivity in the first two stages, the neutron multiplication is not large, while the last one, having a positive reactivity, shows an intense multiplication as is usually expected when handling pulsed systems. This last stage is quite

  6. Pulsed radiation studies of carotenoid radicals and excited states

    Energy Technology Data Exchange (ETDEWEB)

    Burke, M

    2001-04-01

    The one-electron reduction potentials of the radical cations of five dietary carotenoids, in aqueous micellar environments, have been obtained from a pulse radiolysis study of electron transfer between the carotenoids and tryptophan radical cations as a function of pH, and lie in the range 980 to 1060 mV. The decays of the carotenoid radical cations suggest a distribution of exponential lifetimes. The radicals persist for up to about one second, depending on the medium and may re-orientate within a biological environment to react with other biomolecules, such as tyrosine, cysteine or ascorbic acid, which was indeed confirmed. Spectral information of carotenoid pigmented liposomes has been collected, subsequently pulse radiolysis was used to generate the radical cations of {beta}-carotene, zeaxanthin and lutein, in unilamellar vesicles of dipalmitoyl phosphatidyl choline. The rate constants for the 'repair' of these carotenoid radical cations by water-soluble vitamin C were found to be similar ({approx}1 x 10{sup 7} M{sup -1}s{sup -1}) for {beta}-carotene and zeaxanthin and somewhat lower ({approx}0.5 x 10{sup 7} M{sup -1}s{sup -1}) for lutein. The results are discussed in terms of the microenvironment of the carotenoids and suggest that for {beta}-carotene, a hydrocarbon carotenoid, the radical cation is able to interact with a water-soluble species even though the parent hydrocarbon carotenoid is probably entirely in the non-polar region of the liposome. Studies investigating the ability of ingested lycopene to protect human lymphoid cells against singlet oxygen and nitrogen dioxide radical mediated cell damage have shown that a high lycopene diet is beneficial in protecting human cells against reactive oxygen species. Triplet states of carotenoids were produced in benzene solvent and their triplet lifetimes were found to depend on the concentration of the parent molecule. The rate constants obtained for ground state quenching correlate with the number

  7. Neutron depolarization studies on magnetization process using pulsed polarized neutrons

    International Nuclear Information System (INIS)

    Mitsuda, Setsuo; Endoh, Yasuo

    1985-01-01

    Neutron depolarization experiments investigating the magnetization processes have been performed by using pulsed polarized neutrons for the first time. Results on both quenched and annealed ferromagnets of Fe 85 Cr 15 alloy indicate the significant difference in the wavelength dependence of depolarization between them. It also constitutes the experimental demonstration of the theoretical prediction of Halpern and Holstein. (author)

  8. RHEED study of titanium dioxide with pulsed laser deposition

    DEFF Research Database (Denmark)

    Rasmussen, Inge Lise; Pryds, Nini; Schou, Jørgen

    2009-01-01

    Reflection high-energy electron diffraction (RHEED) operated at high pressure has been used to monitor the growth of thin films of titanium dioxide (TiO2) on (1 0 0) magnesium oxide (MgO) substrates by pulsed laser deposition (PLD). The deposition is performed with a synthetic rutile TiO2 target...

  9. Study of a pulsed capillary discharge with a modulated radius

    NARCIS (Netherlands)

    Broks, B.H.P.; Dijk, van W.; Mullen, van der J.J.A.M.; Veldhuizen, van E.M.

    2005-01-01

    In this contribution, we present a plasma physical model of a pulsed capillary discharge with a modulated radius. Using a 2D time-dependent model, we have modeled the plasma and wall properties of this channel. It was found that properties of the central plasma are different than the properties of a

  10. Ultraviolet germicidal efficacy as a function of pulsed radiation parameters studied by spore film dosimetry.

    Science.gov (United States)

    Bauer, Stefan; Holtschmidt, Hans; Ott, Günter

    2018-01-01

    Disinfection by pulsed ultraviolet (UV) radiation is a commonly used method, e.g. in industry or medicine and can be carried out either with lasers or broadband UV radiation sources. Detrimental effects to biological materials depending on parameters such as pulse duration τ or pulse repetition frequency f p are well-understood for pulsed coherent UV radiation, however, relatively little is known for its incoherent variant. Therefore, within this work, it is the first time that disinfection rates of pulsed and continuous (cw) incoherent UV radiation studied by means of spore film dosimetry are presented, compared with each other, and in a second step further investigated regarding two pulse parameters. After analyzing the dynamic range of the Bacillus subtilis spore films with variable cw radiant exposures H=5-100Jm -2 a validation of the Bunsen-Roscoe law revealed its restricted applicability and a 28% enhanced detrimental effect of pulsed compared to cw incoherent UV radiation. A radiant exposure H=50Jm -2 and an irradiance E=0.5Wm -2 were found to be suitable parameters for an analysis of the disinfection rate as a function of τ=0.5-10ms and f p =25-500Hz unveiling that shorter pulses and lower frequencies inactivate more spores. Finally, the number of applied pulses as well as the experiment time were considered with regard to spore film disinfection. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Pulsed Neutron Scattering Studies of Strongly Fluctuating solids, Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Collin Broholm

    2006-06-22

    The conventional description of a solid is based on a static atomic structure with small amplitude so-called harmonic fluctuations about it. This is a final technical report for a project that has explored materials where fluctuations are sufficiently strong to severely challenge this approach and lead to unexpected and potentially useful materials properties. Fluctuations are enhanced when a large number of configurations share the same energy. We used pulsed spallation source neutron scattering to obtain detailed microscopic information about structure and fluctuations in such materials. The results enhance our understanding of strongly fluctuating solids and their potential for technical applications. Because new materials require new experimental techniques, the project has also developed new techniques for probing strongly fluctuating solids. Examples of material that were studied are ZrW2O8 with large amplitude molecular motion that leads to negative thermal expansion, NiGa2S4 where competing interactions lead to an anomalous short range ordered magnet, Pr1- xBixRu2O7 where a partially filled electron shell (Pr) in a weakly disordered environment produces anomalous metallic properties, and TbMnO3 where competing interactions lead to a magneto-electric phase. The experiments on TbMnO3 exemplify the relationship between research funded by this project and future applications. Magneto-electric materials may produce a magnetic field when an electric field is applied or vise versa. Our experiments have clarified the reason why electric and magnetic polarization is coupled in TbMnO3. While this knowledge does not render TbMnO3 useful for applications it will focus the search for a practical room temperature magneto-electric for applications.

  12. Studies of calorimeter absorbers for CW and pulsed CO2 lasers

    International Nuclear Information System (INIS)

    Gunn, S.R.

    1975-01-01

    Solid and liquid absorbers, used in calorimeters to measure the power and energy of cw and pulsed CO 2 lasers, have been studied from 9.24 to 10.76 μm (cw) and near 10.588 μm (pulsed). The principal materials used were magnesium oxide, lithium fluoride, polystyrene, polytetrafluorethylene, carbon tetrachloride and kerosene. (U.S.)

  13. Experimental study of the counting loss in an ionization chamber in pulsed radiation fields

    International Nuclear Information System (INIS)

    Goncalez, O.L.; Yanagihara, L.S.; Veissid, V.L.C.P.; Herdade, S.B.; Teixeira, A.N.

    1983-01-01

    The behavior of an ionization chamber gamma ray monitor in a pulsed radiation field at a linear electron accelerator facility was studied experiementally. A loss of sensitivity was observed as expected due to the pulsed nature of the radiation. By fitting the experiemental data to semi-empirical expressions, parameters for the correction of the counting efficiency were obtained. (Author) [pt

  14. Parametric Study of Pulse-Combustor-Driven Ejectors at High-Pressure

    Science.gov (United States)

    Yungster, Shaye; Paxson, Daniel E.; Perkins, Hugh D.

    2015-01-01

    Pulse-combustor configurations developed in recent studies have demonstrated performance levels at high-pressure operating conditions comparable to those observed at atmospheric conditions. However, problems related to the way fuel was being distributed within the pulse combustor were still limiting performance. In the first part of this study, new configurations are investigated computationally aimed at improving the fuel distribution and performance of the pulse-combustor. Subsequent sections investigate the performance of various pulse-combustor driven ejector configurations operating at highpressure conditions, focusing on the effects of fuel equivalence ratio and ejector throat area. The goal is to design pulse-combustor-ejector configurations that maximize pressure gain while achieving a thermal environment acceptable to a turbine, and at the same time maintain acceptable levels of NOx emissions and flow non-uniformities. The computations presented here have demonstrated pressure gains of up to 2.8%.

  15. Optimisation studies for a moderator on a pulsed neutron source

    International Nuclear Information System (INIS)

    Picton, D.J.; Ross, D.K.; Taylor, A.D.

    1982-01-01

    Having reviewed general aspects of moderator design for pulsed neutron sources, calculations are presented on a number of aspects of moderator optimization. Results of time-independent calculations on metal hydride moderators and a detailed method of evaluating moderated pulse intensities and time distributions, are given. Using computer codes, neutron cross-sections have been calculated from vibrational frequency distributions and time-dependent moderator calculations performed by Monte Carlo methods. The choice of an ambient moderator material and the optimum configuration of heterogeneous poisoning are examined and evaluations of liquid-nitrogen-cooled moderators are presented. Conclusions are drawn concerning the relative merits of cooled and poisoned moderators and an evaluation presented of solid methane at 20 K as a moderator for the production of cold neutrons. (U.K.)

  16. FEASIBILITY STUDY OF PRESSURE PULSING PIPELINE UNPLUGGING TECHNOLOGIES FOR HANFORD

    Energy Technology Data Exchange (ETDEWEB)

    Servin, M. A. [Washington River Protection Solutions, LLC, Richland, WA (United States); Garfield, J. S. [AEM Consulting, LLC (United States); Golcar, G. R. [AEM Consulting, LLC (United States)

    2012-12-20

    The ability to unplug key waste transfer routes is generally essential for successful tank farms operations. All transfer lines run the risk of plugging but the cross site transfer line poses increased risk due to its longer length. The loss of a transfer route needed to support the waste feed delivery mission impacts the cost and schedule of the Hanford clean up mission. This report addresses the engineering feasibility for two pressure pulse technologies, which are similar in concept, for pipeline unplugging.

  17. Feasibility Study Of Pressure Pulsing Pipeline Unplugging Technologies For Hanford

    International Nuclear Information System (INIS)

    Servin, M. A.; Garfield, J. S.; Golcar, G. R.

    2012-01-01

    The ability to unplug key waste transfer routes is generally essential for successful tank farms operations. All transfer lines run the risk of plugging but the cross site transfer line poses increased risk due to its longer length. The loss of a transfer route needed to support the waste feed delivery mission impacts the cost and schedule of the Hanford clean up mission. This report addresses the engineering feasibility for two pressure pulse technologies, which are similar in concept, for pipeline unplugging

  18. CFD study of a simple orifice pulse tube cooler

    Science.gov (United States)

    Zhang, X. B.; Qiu, L. M.; Gan, Z. H.; He, Y. L.

    2007-05-01

    Pulse tube cooler (PTC) has the advantages of long-life and low vibration over the conventional cryocoolers, such as G-M and Stirling coolers because of the absence of moving parts in low temperature. This paper performs a two-dimensional axis-symmetric computational fluid dynamic (CFD) simulation of a GM-type simple orifice PTC (OPTC). The detailed modeling process and the general results such as the phase difference between velocity and pressure at cold end, the temperature profiles along the wall as well as the temperature oscillations at cold end with different heat loads are presented. Emphases are put on analyzing the complicated phenomena of multi-dimensional flow and heat transfer in the pulse tube under conditions of oscillating pressure. Swirling flow pattern in the pulse tube is observed and the mechanism of formation is analyzed in details, which is further validated by modeling a basic PTC. The swirl causes undesirable mixing in the thermally stratified fluid and is partially responsible for the poor overall performance of the cooler, such as unsteady cold-end temperature.

  19. Photoemission studies using femtosecond pulses for high brightness electron beams

    International Nuclear Information System (INIS)

    Srinivasan-Rao, T.; Tsang, T.; Fischer, J.

    1990-06-01

    We present the results of a series of experiments where various metal photocathodes are irradiated with ultrashort laser pulses, whose characteristics are: λ = 625 nm, τ = 100 fs, PRR = 89.5 MHz, Hν = 2 eV and average power 25 mW in each of the two beams. The quantum efficiency of the metals range from ∼10 -12 to 10 -8 at a power density of 100 MW/cm 2 at normal incidence. Since all the electrons are emitted due to multiphoton processes, these efficiencies are expected to increase substantially at large intensities. The efficiency at 100 MW/cm 2 has been increased by using p-polarized light at oblique incidence by ∼20x and by mediating the electron emission through surface plasmon excitation by ∼10 3 x. For the low intensities used in these experiments, the electron pulse duration is almost the same as the laser pulse duration for both the bulk and the surface plasmon mediated photoemission. 7 refs., 8 figs., 2 tabs

  20. Photosynthetic pigments and model compounds studied by pulse radiolysis

    International Nuclear Information System (INIS)

    Jensen, N.-H.

    1980-05-01

    The photosynthetic pigments chlorophyll a and alltrans-β-carotene as well as the quinone model compound duroquinone have been studied in solution by pulse radiolysis combined with time-resolved absorption and resonance Raman spectroscopy. In benzene solution the excited triplet states of the subtrates were produced either directly in the case of duroquinone or by triplet energy transfer from triplet naphthalene in the case of chlorophyll a and β-carotene. All relevant rate constants involved in the reactions of the excited states in benzene were determined, including i) the rate constants for energy transfer from triplet naphthalene to chlorophyll a with k = (3.6+-0.6).10 9 M -1 s -1 and β-carotene with k = (10.7+-1.2).10 9 M -1 s -1 ii) the rate constants of triplet annihilation of chlorophyll a: (1.4+-0.3).10 9 M -1 s -1 , β-carotene: (3.6+-0.4).10 9 M -1 s -1 , duroquinone: (3.0+-0.6).10 9 M -1 s -1 . For β-carotene it is suggested that triplet-triplet annihilation produces the optically forbidden excited 1 Asub(g) state. The first-order components of the triplet decays were strongly dependent upon irradiation dose in the case of naphthalene and duroquinone but apparently only slightly dependent on or independent or irradiation dose in the case of chlorophyll a and β-carotene. Apparent bimolecular rate constants for triplet quenching by radiolytically produced free radicals are determined. The triplet state of duroquinone is quenched by ground state duroquinone with a rate constant of (1.2+-0.3).10 6 M -1 s -1 . The excited triplet state of all-trans-β-carotene has been investigated by time-resolved resonance Raman spectroscopy. Six transient Raman bands at 965 cm -1 , 1009 cm -1 , 1125 cm -1 , 1188 cm -1 , 1236 cm -1 and 1496 cm -1 were observed. The spectra suggest that the C = C band order is decreased and that the molecule may be substantially twisted, presumably at the 15,15 1 band, in the triplet state. The radical anion of chlorophyll a with

  1. Study and realisation of a femtosecond dye laser operating at different wavelengths. Ultrashort pulses compression and amplification

    International Nuclear Information System (INIS)

    Georges, Patrick

    1989-01-01

    We present the study and the realization of a passively mode-locked dye laser producing pulses shorter than 100 femto-seconds (10 -13 s). In a ring cavity with an amplifier medium (Rhodamine 60) and a saturable absorber (DODCI), a sequence of four prisms controls the group velocity dispersion and allows the generation of very short pulses. Then we have studied the production of femtosecond pulses at other wavelengths directly from the femtosecond dye laser. For the first rime, 60 fs pulses at 685 nm and pulses shorter than 50 fs between 775 nm and 800 nm have been produced by passive mode locking. These near infrared pulses have been used to study the absorption saturation kinetics in semiconductors multiple quantum wells GaAs/GaAlAs. We have observed a singular behavior of the laser operating at 685 nm and analyzed the produced pulses in terms of optical solitons. To perform time resolved spectroscopy with shortest pulses, we have studied a pulse compressor and a multipass amplifier to increase the pulses energy. Pulses of 20 fs and 10 micro-joules (peak power: 0.5 GW) have been obtained at low repetition rate (10 Hz) and pulses of 16 fs and 0.6 micro-joules pulses have been generated at high repetition rate (11 kHz) using a copper vapor laser. These pulses have been used to study the absorption saturation kinetics of an organic dye (the Malachite Green). (author) [fr

  2. Note: Tesla based pulse generator for electrical breakdown study of liquid dielectrics

    Science.gov (United States)

    Veda Prakash, G.; Kumar, R.; Patel, J.; Saurabh, K.; Shyam, A.

    2013-12-01

    In the process of studying charge holding capability and delay time for breakdown in liquids under nanosecond (ns) time scales, a Tesla based pulse generator has been developed. Pulse generator is a combination of Tesla transformer, pulse forming line, a fast closing switch, and test chamber. Use of Tesla transformer over conventional Marx generators makes the pulse generator very compact, cost effective, and requires less maintenance. The system has been designed and developed to deliver maximum output voltage of 300 kV and rise time of the order of tens of nanoseconds. The paper deals with the system design parameters, breakdown test procedure, and various experimental results. To validate the pulse generator performance, experimental results have been compared with PSPICE simulation software and are in good agreement with simulation results.

  3. Experimental studies of the overshoot and undershoot in pulse-modulated radio-frequency atmospheric discharge

    Energy Technology Data Exchange (ETDEWEB)

    Huo, W. G.; Li, R. M.; Shi, J. J. [School of Physics and Electronic Technology, Liaoning Normal University, Dalian 116029 (China); Ding, Z. F., E-mail: huowg.wg@tom.com [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116023 (China)

    2016-08-15

    The overshoot and undershoot of the applied voltage on the electrodes, the discharge current, and radio frequency (RF) power were observed at the initial phase of pulse-modulated (PM) RF atmospheric pressure discharges, but factors influencing the overshoot and undershoot have not been fully elucidated. In this paper, the experimental studies were performed to seek the reasons for the overshoot and undershoot. The experimental results show that the overshoot and undershoot are associated with the pulse frequency, the rise time of pulse signal, and the series capacitor C{sub s} in the inversely L-shaped matching network. In the case of a high RF power discharge, these overshoot and undershoot become serious when shortening the rise time of a pulse signal (5 ns) or operating at a moderate pulse frequency (500 Hz or 1 kHz).

  4. Experimental Study of RF Pulsed Heating on Oxygen Free Electronic Copper

    Energy Technology Data Exchange (ETDEWEB)

    Pritzkau, David P.

    2003-02-10

    When the thermal stresses induced by RF pulsed heating are larger than the elastic limit, microcracks and surface roughening will occur due to cyclic fatigue. Therefore, pulsed heating limits the maximum surface magnetic field and through it the maximum achievable accelerating gradient. An experiment using circularly cylindrical cavities operating in the TE{sub 011} mode at a resonant frequency of 11.424 GHz was designed to study pulsed heating on Oxygen Free Electronic (OFE) copper. An X-band klystron delivered up to 10 MW to the cavities in 1.5 {micro}s pulses at 60 Hz repetition rate. One run was executed at a temperature rise of 120 K for 56 x 10{sup 6} pulses. Cracks at grain boundaries, slip bands and cracks associated with these slip bands were observed. The second run consisted of 86 x 10{sup 6} pulses with a temperature rise of 82 K, and cracks at grain boundaries and slip bands were seen. Additional information can be derived from the power-coupling iris, and we conclude that a pulsed temperature rise of 250 K for several million pulses leads to destruction of copper. These results can be applied to any mode of any OFE copper cavity.

  5. Randomized, double-blind, comparative study on efficacy and safety of itraconazole pulse therapy and terbinafine pulse therapy on nondermatophyte mold onychomycosis: A study with 90 patients.

    Science.gov (United States)

    Ranawaka, Ranthilaka R; Nagahawatte, Ajith; Gunasekara, Thusitha Aravinda; Weerakoon, Hema S; de Silva, S H Padmal

    2016-08-01

    Nondermatophyte mold (NDM) onychomycosis shows poor response to current topical, oral or device-related antifungal therapies. This study was aimed to determine the efficacy and safety of itraconazole and terbinafine pulse therapy on NDM onychomycosis. Mycologically proven subjects were treated with itraconazole 400 mg daily or terbinafine 500 mg daily for 7 days/month; two pulses for fingernails and three pulses for toenails(SLCTR/2013/013). One-hundred seventy-eight patients underwent mycological studies and 148 had positive fungal isolates. NDM were the prevailing fungi, 68.2%, followed by candida species 21.6%, and dermatophytes made up only 10.1%. Out of NDM Aspergillus spp (75.1%) predominated followed by 8.9% Fusarium spp and 4.95% Penicillium spp. The clinical cure at completion of pulse therapy was statistically significant 9.2% versus 2.0% (p terbinafine pulse cured 55.0% Aspergillus spp and 50.0% Fusarium spp. NDM was the prevailing fungi in onychomycosis in Sri Lanka. Both itraconazole and terbinafine were partially effective on NDM onychomycosis showing a clinical cure of 54-65%. Future research should focus on searching more effective antifungal for NDM onychomycosis.

  6. A pulse radiolysis study of hyperoside isolated from Hypericum mysorense

    International Nuclear Information System (INIS)

    Hariharapura, Raghu C.; Mahal, H.S.; Srinivasan, R.; Jagani, Hitesh; Vijayan, P.

    2015-01-01

    Background: The recent growth in knowledge of free radicals in biology is producing a medical revolution that promises a new age in health and disease management. In the last two decades there has been an explosive interest in the role of oxygen free radicals, more generally known as “reactive oxygen species” and of “reactive nitrogen species” in experimental and clinical medicine. Methods: The flowering top extract of Hypericum mysorense possessing potent anti-oxidant activity was subjected to bio-active guided isolation. Pulse radiolysis technique was used to determine the transient spectrum and rate constant for the one-electron oxidation of hyperoside by · OH, N 3 · , NO 2 · , NO · , CCl 3 OO · radicals in aqueous solution. Results: Three compounds were isolated and characterized as rutin, quercetin-3-O-galactoside (hyperoside) and quercetin from spectral analysis. The hyperoside radical showed pK a1 and pK a2 at 5.4 and 9.2. Both, Cu(II) and iron(II) ions form chelate with hyperoside. The Cu–hyperoside chelate was able to scavenge O 2 ·− , k=7.0(±0.3)×10 6 dm 3 mol −1 s −1 at pH 9. The repair rates for tryptophan and guanosine radicals by hyperoside were also determined. Conclusion: The reduction potential of hyperoside radical was determined by cyclic voltammetric and pulse radiolysis methods. - Highlights: • Hyperoside, rutin and quercetin were isolated from extract of Hypericum mysorense. • Rate constant of hyperoside was determined by Pulse radiolysis technique. • The hyperoside radical showed pK a1 and pK a2 at 5.4 and 9.2. • Cu(II) and iron(II)ions form chelate with hyperoside. • Hyperoside can repair the damage to guanosine, tryptophan radicals

  7. Numerical study of the propagation of high power microwave pulses in air breakdown environment

    International Nuclear Information System (INIS)

    Kim, J.; Kuo, S.P.

    1992-01-01

    A theoretical model based on a set of two modal equations has been developed to describe self-consistently the propagation of an intense microwave pulse in an air breakdown environment. It includes Poynting's equation for the continuity of the power flux of the pulse and the rate equation of the electron density. A forward wave approximation is used to simplify Poynting's equation and a semi-empirical formula for the ionization frequency as a function of the wave field amplitude is adopted for this model. In order to improve the numerical efficiency of the model in terms of the required computation time and available subroutines for numerical analysis of pulse propagation over a long distance, a transformation to the frame of local time of the pulse is introduced. The effect of space-time dependence of the group velocity of the pulse is included in this properly designed transformation. The inhomogeneous feature of the background pressure is also preserved in the model. The resultant equations are reduced to the forms which can be solved directly by the available subroutine of ODE solver. In this work, a comprehensive numerical analysis of the propagation of high power microwave pulse through the atmosphere is performed. It is shown that the pulse energy can severely be attenuated by the self-generated plasma. Therefore, the aim of the present study is to identify the optimum parameters of the pulse so that the energy loss of the pulse before reaching the destination can be minimized. These parameters include the power, frequency, shape and length of the pulse. The conditions for maximizing the ionization at a destinated region in the upper atmosphere will also be determined

  8. Proposals of electronic-vibrational energy relaxation studies by using laser pulses synchronized with IR-SR pulses

    International Nuclear Information System (INIS)

    Nakagawa, Hideyuki

    2000-01-01

    Synchrotron radiation is expected to be the sharp infrared light source for the advanced experiments on IR and FIR spectroscopy in wide research fields. Especially, synchronized use of SR with VIS and/or UV laser light is to be a promising technique for the research on the dynamical properties of the photo-excited states in condensed materials. Some proposals are attempted for high resolution IR spectroscopy to elucidate fine interaction of molecular ions in crystalline solids with their environmental field and for time-resolved IR spectroscopic studies on the electronic and vibrational energy relaxation by using laser pulses synchronized with IR-SR pulses. Several experimental results are presented in relevance to the subjects; on high-resolution FTIR spectra of cyanide ions and metal cyanide complexes in cadmium halide crystals, on the energy up-conversion process among the vibrational levels of cyanide ions in alkali halide crystals, and on the electronic-to-vibrational energy conversion process in metal cyanide complexes. (author)

  9. A feasibility study for a contained pulsed nuclear propulsion concept

    International Nuclear Information System (INIS)

    Parlos, A.G.; Metzger, J.D.

    1993-01-01

    A preliminary analysis of a pulsed propulsion concept is performed utilizing the enormously dense energy generated by small nuclear detonations. The concept feasibility is based on the premise that current materials technology has undergone significant breakthroughs, allowing design of pressure vessels capable of containing the blast associated with such detonations. Furthermore, the rapid energy transfer to the propellant, allows generation of high thrust levels for up to 10 ms following the detonation. Preliminary reevaluation of the concept using off-the-shelf materials technology appears to indicate that the contained pulsed nuclear propulsion concept has no major flaws, and it can provide thrust levels resulting in average thrust-to-weight ratios on the order of 2--2.5 over an engine operating cycle. Furthermore, even though the specific impulse is not a good performance indicator for impulsive engines, operating-cycle-averaged specific impulse of approximately 1800 s has been calculated. The engine mass associated with this performance is on the order of 50 Mg. The concept appears attractive for a number of missions planned for the Space Exploration Initiative, however, there are still a number of issues that must be addressed

  10. Study on irradiation effects of nucleus electromagnetic pulse on single chip computer system

    International Nuclear Information System (INIS)

    Hou Minsheng; Liu Shanghe; Wang Shuping

    2001-01-01

    Intense electromagnetic pulse, namely nucleus electromagnetic pulse (NEMP), lightning electromagnetic pulse (LEMP) and high power microwave (HPM), can disturb and destroy the single chip computer system. To study this issue, the authors made irradiation experiments by NEMPs generated by gigahertz transversal electromagnetic (GTEM) Cell. The experiments show that shutdown, restarting, communication errors of the single chip microcomputer system would occur when it was irradiated by the NEMPs. Based on the experiments, the cause on the effects on the single chip microcomputer system is discussed

  11. Study of {sup 14}N NQR response to SORC pulse sequence

    Energy Technology Data Exchange (ETDEWEB)

    Konnai, A., E-mail: konnai@nmri.go.jp; Odano, N. [National Maritime Research Institute, Department of Navigation and System Engineering (Japan); Asaji, T. [Nihon University, Department of Chemistry, College of Humanities and Sciences (Japan)

    2008-01-15

    The behavior of nuclear quadrupole resonance (NQR) signals between RF pulses of the strong off-resonance comb (SORC) as well as the spin-locking spin-echo (SLSE) pulse sequences was studied as for {sup 14}N NQR line {nu}{sub +} of dimethylnitramine (CH{sub 3}){sub 2}NNO{sub 2} at 77 K. The periodic variation of the signal amplitude observed by using SORC pulse sequence could be reasonably explained by the theoretical expression reported in the literature.

  12. Time resolved studies of H{sub 2}{sup +} dissociation with phase-stabilized laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Bettina

    2010-06-23

    In the course of this thesis, experimental studies on the dissociation of H{sub 2}{sup +}(H{sub 2}{sup +}{yields}p+H) in ultrashort laser pulses with a stabilized carrier-envelope phase (CEP) were carried out. In single-pulse measurements, the ability to control the emission direction of low energetic protons, i.e. the localization of the bound electron at one of the nuclei after dissociation, by the CEP was demonstrated. The coincident detection of the emitted protons and electrons and the measurement of their three-dimensional momentum vectors with a reaction microscope allowed to clarify the localization mechanism. Further control was achieved by a pump-control scheme with two timedelayed CEP-stabilized laser pulses. Here the neutral H{sub 2} molecule was ionized in the first pulse and dissociation was induced by the second pulse. Electron localization was shown to depend on the properties of the bound nuclear wave packet in H{sub 2}{sup +} at the time the control pulse is applied, demonstrating the ability to use the shape and dynamics of the nuclear wave packet as control parameters. Wave packet simulations were performed reproducing qualitatively the experimental results of the single and the two-pulse measurements. For both control schemes, intuitive models are presented, which qualitatively explain the main features of the obtained results. (orig.)

  13. Time resolved studies of H2+ dissociation with phase-stabilized laser pulses

    International Nuclear Information System (INIS)

    Fischer, Bettina

    2010-01-01

    In the course of this thesis, experimental studies on the dissociation of H 2 + (H 2 + →p+H) in ultrashort laser pulses with a stabilized carrier-envelope phase (CEP) were carried out. In single-pulse measurements, the ability to control the emission direction of low energetic protons, i.e. the localization of the bound electron at one of the nuclei after dissociation, by the CEP was demonstrated. The coincident detection of the emitted protons and electrons and the measurement of their three-dimensional momentum vectors with a reaction microscope allowed to clarify the localization mechanism. Further control was achieved by a pump-control scheme with two timedelayed CEP-stabilized laser pulses. Here the neutral H 2 molecule was ionized in the first pulse and dissociation was induced by the second pulse. Electron localization was shown to depend on the properties of the bound nuclear wave packet in H 2 + at the time the control pulse is applied, demonstrating the ability to use the shape and dynamics of the nuclear wave packet as control parameters. Wave packet simulations were performed reproducing qualitatively the experimental results of the single and the two-pulse measurements. For both control schemes, intuitive models are presented, which qualitatively explain the main features of the obtained results. (orig.)

  14. Pulse radiolysis studies of bergenin, an isocoumarin polyphenolic derivative

    International Nuclear Information System (INIS)

    Singh, Umang; Srinivasan, R.; Barik, A.; Priyadarsini, K.I.

    2008-01-01

    Bergenin, a polyphenolic isocoumarin derivative, isolated from medicinal plant Caesalpinia digynae, has been subjected for OH and oxidizing radical reactions using pulse radiolysis technique coupled with absorption detection. OH radicals cause multiple reactions, producing transients absorbing with maxima at 440 nm and 500 nm. By comparing the spectra and decay kinetics with that produced by N 3 radicals, the species absorbing at 440 nm is assigned to phenoxyl type radical and the one absorbing at 500 nm to be a hydroxyl-radical adduct, which has been found to be reducing in nature. Bergenin also reacts with peroxyl radicals, with rate constants of 4.2 x 10 6 M -1 s -1 . (author)

  15. Pulse radiolysis studies of bergenin, an isocoumarin polyphenolic derivative

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Umang; Srinivasan, R; Barik, A; Priyadarsini, K I [Radiation and Photochemistry Div., Bhabha Atomic Research Centre, Mumbai (India)

    2008-01-15

    Bergenin, a polyphenolic isocoumarin derivative, isolated from medicinal plant Caesalpinia digynae, has been subjected for OH and oxidizing radical reactions using pulse radiolysis technique coupled with absorption detection. OH radicals cause multiple reactions, producing transients absorbing with maxima at 440 nm and 500 nm. By comparing the spectra and decay kinetics with that produced by N{sub 3} radicals, the species absorbing at 440 nm is assigned to phenoxyl type radical and the one absorbing at 500 nm to be a hydroxyl-radical adduct, which has been found to be reducing in nature. Bergenin also reacts with peroxyl radicals, with rate constants of 4.2 x 10{sup 6} M{sup -1}s{sup -1}. (author)

  16. NeuRad detector prototype pulse shape study

    Science.gov (United States)

    Muzalevsky, I.; Chudoba, V.; Belogurov, S.; Kiselev, O.; Bezbakh, A.; Fomichev, A.; Krupko, S.; Slepnev, R.; Kostyleva, D.; Gorshkov, A.; Ovcharenko, E.; Schetinin, V.

    2018-04-01

    The EXPERT setup located at the Super-FRS facility, the part of the FAIR complex in Darmstadt, Germany, is intended for investigation of properties of light exotic nuclei. One of its modules, the high granularity neutron detector NeuRad assembled from a large number of the scintillating fiber is intended for registration of neutrons emitted by investigated nuclei in low-energy decays. Feasibility of the detector strongly depends on its timing properties defined by the spatial distribution of ionization, light propagation inside the fibers, light emission kinetics and transition time jitter in the multi-anode photomultiplier tube. The first attempt of understanding the pulse formation in the prototype of the NeuRad detector by comparing experimental results and Monte Carlo (MC) simulations is reported in this paper.

  17. Radiation chemistry and advanced polymer materials studied by picosecond pulse radiolysis combined with femtosecond laser

    International Nuclear Information System (INIS)

    Tagawa, S.; Yoshida, Y.; Miki, M.; Yamamoto, T.; Ushida, K.; Izumi, Y.

    1996-01-01

    We have synchronized a single picosecond MeV electron pulse from L-band linear accelerator (linac) of The Institute of Scientific and Industrial Research of Osaka University to a single femtosecond laser pulse of Ti:Sapphire laser. It is an essential technique for the future femtosecond pulse radiolysis and is also applied to many kinds of combined application of more than two different beams from accelerators in very short time range. Radiation chemistry and new type of polymers have been studied by LL (laser-linac) twin picosecond pulse radiolysis. Especially the early events in radiation chemistry such as geminate recombination processes of electrons and radical cations are have been studied in both liquids and solids. (author)

  18. Neutronic studies on decoupled hydrogen moderator for a short-pulse spallation source

    International Nuclear Information System (INIS)

    Harada, Masahide; Watanabe, Noboru; Teshigawara, Makoto; Kai, Tetsuya; Ikeda, Yujiro

    2005-01-01

    Neutronic studies of decoupled hydrogen moderators were performed by calculations taking into account para hydrogen content, decoupling energy, moderator dimensions/shapes and reflector material. Low-energy parts of calculated spectral intensities with different para hydrogen contents were analyzed by a modified Maxwell function to characterize neutron spectra. The result shows that a 100% para hydrogen moderator gives the highest pulse peak intensity together with the narrowest pulse width and the shortest decay times. Pulse broadening with a reflector was explained by time distributions of source neutrons entering into the moderator through a decoupler. Material dependence of time distribution was studied. A decoupling energy higher than 1 eV does not bring about a large improvement in pulse widths and decay times, even at a large penalty in the peak intensity. The optimal moderator thickness was also discussed for a rectangular parallelepipe-shaped and a canteen-shaped moderator

  19. Thermodynamic Basis of Electron Transfer in Dihydroorotate Dehydrogenase B from Lactococcus lactis:  Analysis by Potentiometry, EPR Spectroscopy, and ENDOR Spectroscopy

    DEFF Research Database (Denmark)

    Mohnsen, Al-Walid A.; Rigby, Stephen E. J.; Jensen, Kaj Frank

    2004-01-01

    Dihydroorotate dehydrogenase B (DHODB) is a complex iron-sulfur flavoprotein that catalyzes the conversion of dihydroorotate to orotate and the reduction of NAD+. The enzyme is a dimer of heterodimers containing an FMN, an FAD, and a 2Fe-2S center. UV-visible, EPR, and ENDOR spectroscopies have...... similar to those recorded for the blue semiquinone of free flavins in aqueous solution, thus confirming the presence of this species in DHODB. Spectral features observed during EPR spectroscopy of dithionite-reduced DHODB are consistent with the midpoint reduction potentials determined using UV-visible...... spectroscopy and further identify an unusual EPR signal with very small rhombic anisotropy and g values of 2.02, 1.99, and 1.96. This unusual signal is assigned to the formation of a spin interacting state between the FMN semiquinone species and the reduced 2Fe-2S center. Reduction of DHODB using an excess...

  20. Spectroscopic studies on diamond like carbon films synthesized by pulsed laser ablation

    Energy Technology Data Exchange (ETDEWEB)

    Panda, Madhusmita; Krishnan, R., E-mail: krish@igcar.gov.in; Ravindran, T. R.; Das, Arindam; Mangamma, G.; Dash, S.; Tyagi, A. K. [Material Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam - 603102, Tamil Nadu (India)

    2016-05-23

    Hydrogen free Diamond like Carbon (DLC) thin films enriched with C-C sp{sup 3} bonding were grown on Si (111) substrates at laser pulse energies varying from 100 to 400 mJ (DLC-100, DLC-200, DLC-300, DLC-400), by Pulsed Laser Ablation (PLA) utilizing an Nd:YAG laser operating at fundamental wavelength. Structural, optical and morphological evolutions as a function of laser pulse energy were studied by micro Raman, UV-Vis spectroscopic studies and Atomic Force Microscopy (AFM), respectively. Raman spectra analysis provided critical clues for the variation in sp{sup 3} content and optical energy gap. The sp{sup 3} content was estimated using the FWHM of the G peak and found to be in the range of 62-69%. The trend of evolution of sp{sup 3} content matches well with the evolution of I{sub D}/I{sub G} ratio with pulse energy. UV-Vis absorption study of DLC films revealed the variation of optical energy gap with laser pulse energy (1.88 – 2.23 eV), which matches well with the evolution of G-Peak position of the Raman spectra. AFM study revealed that roughness, size and density of particulate in DLC films increase with laser pulse energy.

  1. The use of pulsed power ion/electron beams for studying of units of electronuclear reactor

    Energy Technology Data Exchange (ETDEWEB)

    Korenev, S A; Korenev, A S; Puzynin, I V; Samojlov, V N; Sissakyan, A N [Joint Institute for Nuclear Research, Dubna (Russian Federation)

    1997-12-31

    The problems associated with the use of power pulsed ion beams for studying some units of the model electronuclear installation are considered. This makes it possible to analyze the problem of heating loads on the targets, entrance and exit windows for beams of charged particles. The methods of increasing the life-time of these thin foil based windows by surface modification of the materials by high current pulsed ion beams are considered. (author). 4 figs., 5 refs.

  2. The use of pulsed power ion/electron beams for studying of units of electronuclear reactor

    Energy Technology Data Exchange (ETDEWEB)

    Korenev, S.A.; Korenev, A.S.; Puzynin, I.V.; Samoilov, V.N.; Sissakian, A.N. [Joint Inst. for Nuclear Research, Dubna (Russian Federation)

    1997-09-01

    The questions of using power pulsed ion beams for studying some units of model`s electronuclear installation are considered in this report. It allows to analyze the question of heating loads on the targets, entering and output windows for beams of charge particles. The methods of increasing a life-time of these windows on the basis of thin foils with help of surface modification of materials by high current pulsed ion beams are considered. 5 refs., 4 figs.

  3. The use of pulsed power ion/electron beams for studying of units of electronuclear reactor

    International Nuclear Information System (INIS)

    Korenev, S.A.; Korenev, A.S.; Puzynin, I.V.; Samojlov, V.N.; Sissakyan, A.N.

    1996-01-01

    The problems associated with the use of power pulsed ion beams for studying some units of the model electronuclear installation are considered. This makes it possible to analyze the problem of heating loads on the targets, entrance and exit windows for beams of charged particles. The methods of increasing the life-time of these thin foil based windows by surface modification of the materials by high current pulsed ion beams are considered. (author). 4 figs., 5 refs

  4. The use of pulsed power ion/electron beams for studying of units of electronuclear reactor

    International Nuclear Information System (INIS)

    Korenev, S.A.; Korenev, A.S.; Puzynin, I.V.; Samoilov, V.N.; Sissakian, A.N.

    1997-01-01

    The questions of using power pulsed ion beams for studying some units of model's electronuclear installation are considered in this report. It allows to analyze the question of heating loads on the targets, entering and output windows for beams of charge particles. The methods of increasing a life-time of these windows on the basis of thin foils with help of surface modification of materials by high current pulsed ion beams are considered. 5 refs., 4 figs

  5. Simulation study of a pulsed neutron focusing using a pulsed electromagnetic lens coupled with a permanent magnet

    International Nuclear Information System (INIS)

    Iwashita, H.; Iwasa, H.; Hiraga, F.; Kamiyama, T.; Kiyanagi, Y.; Suzuki, J.; Shinohara, T.; Oku, T.; Shimizu, H.M.

    2009-01-01

    A pulsed sextupole electromagnetic lens with suitably controlled time-dependent magnetic field can in principle focus pulsed neutrons at the same focal point over a wide range of wavelength as the lens removes aberrations. However, in fact, it is difficult to focus neutrons over a wide range of wavelength because attenuation of a practical pulsed sextupole electromagnet is faster than an ideal case. We have devised a method of canceling the difference between the practical pulsed sextupole magnetic field and the ideal magnetic field with the use of a permanent sextupole magnet. We performed simulation calculations to investigate the feasibility of this method, and it was shown that focusing wavelength range spread compared with the case using a pulsed magnetic lens only. This result indicates the usefulness of the method.

  6. Infrared study of the Crab pulsar: The ''shoulder'' pulse and the 3.45 micron pulse profile

    International Nuclear Information System (INIS)

    Middleditch, J.; Pennypacker, C.; Burns, M.S.

    1983-01-01

    Infrared measurements of the Crab pulsar with the NASA IRTF 3.0 m telescope show that the spectrum of the main pulse turns downward for wavelengths longer than 3 μm. The ''shoulder'' pulse discovered by Pennypacker is measured in the 0.9--2.4 μm region, but disappears at 3.5 μm. This pulse rises from 0 to 20% of the height of the main pulse within 1 to 2 ms after the main pulse peak and decays with a 4 to 5 ms time constant. Excess infrared flux also appears after the interpulse. The main peak itself may be narrower at 3.45 μm than in the optical to 2.2 μm band

  7. XPS studies of short pulse laser interaction with copper

    International Nuclear Information System (INIS)

    Stefanov, P.; Minkovski, N.; Balchev, I.; Avramova, I.; Sabotinov, N.; Marinova, Ts.

    2006-01-01

    The effect of laser ablation on copper foil irradiated by a short 30 ns laser pulse was investigated by X-ray photoelectron spectroscopy. The laser fluence was varied from 8 to 16.5 J/cm 2 and the velocity of the laser beam from 10 to 100 mm/s. This range of laser fluence is characterized by a different intensity of laser ablation. The experiments were done in two kinds of ambient atmosphere: air and argon jet gas. The chemical state and composition of the irradiated copper surface were determined using the modified Auger parameter (α') and O/Cu intensity ratio. The ablation atmosphere was found to influence the size and chemical state of the copper particles deposited from the vapor plume. During irradiation in air atmosphere the copper nanoparticles react with oxygen and water vapor from the air and are deposited in the form of a CuO and Cu(OH) 2 thin film. In argon atmosphere the processed copper surface is oxidized after exposure to air

  8. Pulse radiolysis studies concerning oxidative degradation processes in linear polymers

    International Nuclear Information System (INIS)

    Schnabel, Wolfram

    1986-01-01

    On the basis of pulse radiolysis experiments carried out with various polymers in dilute solution three modes of action of molecular oxygen, 0 2 , can be discriminated with respect to main-chain scission: (a) 0 2 acts as a promoter, (b) 0 2 acts as an inhibitor, and (c) 0 2 acts as a fixing agent for main-chain breaks. The promoting mode of action (a) is due to the inhibition of simultaneously occurring intermolecular crosslinking (DNA, polymethylvinylketone) and/or to the combination of peroxyl radicals with the subsequent formation of readily decomposing oxyl radicals (polyethylene oxide, polyacrylamide, polyvinylpyrrolidone, polyribouridylic acid, polyriboadenylic acid, polyribocytidylic acid). The inhibiting mode of action (b) pertains to the reaction of 0 2 with macroradicals that otherwise undergo main-chain rupture (amylose polymethylmethacrylate). Fixing of main-chain ruptures (mode c) becomes important, if macroradicals generated by a very fast rupture of bonds in the main-chain, are prone to recombine quickly. This mode of action was evidenced in the case of polybutenesulfone where main-chain scission involves the extrusion of small segments of the chain. (author)

  9. Moessbauer and XRD study of pulse plated Fe-P and Fe-Ni thin layers

    Energy Technology Data Exchange (ETDEWEB)

    Miko, Annamaria [Bay Zoltan Institute for Material Science (Hungary); Kuzmann, Erno, E-mail: kuzmann@para.chem.elte.hu [Eoetvoes Lorand University, Research Group for Nuclear Methods in Structural Chemistry, Hungarian Academy of Sciences, Department of Nuclear Chemistry (Hungary); Lakatos-Varsanyi, Magda [Bay Zoltan Institute for Material Science (Hungary); Kakay, Attila [Research Institute for Solid State Physics and Optics (Hungary); Nagy, Ferenc [Eoetvoes Lorand University, Research Group for Nuclear Methods in Structural Chemistry, Hungarian Academy of Sciences, Department of Nuclear Chemistry (Hungary); Varga, Lajos Karoly [Research Institute for Solid State Physics and Optics (Hungary)

    2005-09-15

    {sup 57}Fe conversion electron Moessbauer spectroscopy, X-ray diffraction, electrochemical and magnetic measurements were used to study pulse electroplated Fe-P and Ni-Fe coatings. XRD and {sup 57}Fe CEMS measurements revealed the amorphous character of the novel pulse plated Fe-P alloys. CEM spectra indicated significant differences in the short range order and in the magnetic anisotropy between the Fe-P deposits pulse plated at medium long deposition time (t{sub on} = 2 ms), with short relaxation time (t{sub off} = 9 ms) and low current density (I{sub p} = 0.05 Acm{sup -2}) or at short deposition time (t{sub on} = 1 ms) with long relaxation time (t{sub off} = 250 ms) and high current density (I{sub p} = 1.0 Acm{sup -2}). The broad peaks centred around the fcc reflections in XRD of the pulse plated Ni-22 wt.% Fe deposit reflected a microcrystalline Ni-Fe alloy with a very fine, 5-8 nm, grain size. The CEM spectrum of the pulse plated Ni-22 wt.% Fe coating corresponded to a highly disordered solid solution alloy containing a minute amount of ferrihydrite. Extreme favourable soft magnetic properties were observed with these Ni-Fe and Fe-P pulse plated thin layers.

  10. Moessbauer and XRD study of pulse plated Fe-P and Fe-Ni thin layers

    International Nuclear Information System (INIS)

    Miko, Annamaria; Kuzmann, Erno; Lakatos-Varsanyi, Magda; Kakay, Attila; Nagy, Ferenc; Varga, Lajos Karoly

    2005-01-01

    57 Fe conversion electron Moessbauer spectroscopy, X-ray diffraction, electrochemical and magnetic measurements were used to study pulse electroplated Fe-P and Ni-Fe coatings. XRD and 57 Fe CEMS measurements revealed the amorphous character of the novel pulse plated Fe-P alloys. CEM spectra indicated significant differences in the short range order and in the magnetic anisotropy between the Fe-P deposits pulse plated at medium long deposition time (t on = 2 ms), with short relaxation time (t off = 9 ms) and low current density (I p = 0.05 Acm -2 ) or at short deposition time (t on = 1 ms) with long relaxation time (t off = 250 ms) and high current density (I p = 1.0 Acm -2 ). The broad peaks centred around the fcc reflections in XRD of the pulse plated Ni-22 wt.% Fe deposit reflected a microcrystalline Ni-Fe alloy with a very fine, 5-8 nm, grain size. The CEM spectrum of the pulse plated Ni-22 wt.% Fe coating corresponded to a highly disordered solid solution alloy containing a minute amount of ferrihydrite. Extreme favourable soft magnetic properties were observed with these Ni-Fe and Fe-P pulse plated thin layers.

  11. Pulse radiolysis studies on liquid alkanes and related polymers

    International Nuclear Information System (INIS)

    Tagawa, S.; Hayashi, N.; Yoshida, Y.; Washio, M.; Tabata, Y.

    1989-01-01

    Absorption spectra of alkane radical cations, alkane excited states, and alkyl radicals and electrons in irradiated neat liquid alkanes at room temperature were assigned on subnanosecond and nanosecond time scale after an electron pulse. Two broad visible and near-infrared absorption bands of alkane excited states and radical cations, and UV absorption band of alkyl radicals was observed in neat n-alkanes. In neat cyclohezane and trans-decalin, very broad visible absorption band mainly due to alkane excited states and UV absorption band of alkyl radicals were observed. In neat neopentane and isooctane, visible absorption bands were not observed, although UV absorption bands of alkyl radicals were observed. The wavelengths of absorptive peaks of alkane radical cations and excited states become longer with increasing the number of carbon atoms of n-alkanes. The lifetimes of alkane radical cations become shorter with decreasing the number of carbon atoms of n-alkanes and are shorter than those of electrons in neat alkanes. The main processes of the alkyl radical formation finish within the time resolution of our system (about 20 ps). The alkyl radicals are produced mainly from excited radicals cations and partly from higher excited states, the lowest excited states, radical cations, and thermal hydrogen atoms, In irradiated ethylene-propylene copolymers, broad absorption bands of excited states and tail parts of absorption bands of radical cations and electrons were observed in visible and near-infrared region, although UV absorption of alkyl radicals was not confirmed lack of transparency of polymer films. (author)

  12. Lithium-sodium separation by ion-exchange. Particular study of a pulsed column

    International Nuclear Information System (INIS)

    Auvert, H.

    1966-02-01

    A study is made of the operational conditions and constraints in the case of a moving-bed ion-exchange column subjected to pulses. The example chosen to illustrate its application concerns the lithium-sodium separation in a hydroxide medium (LiOH, NaOH). In the first part, the physico-chemical characteristics of the exchange and the kinetic characteristics of the exchange-reaction are considered. In the second part, the operation of the pulsed column is studied. Using the results obtained in the first part, the conditions required for study state operation are determined. When this is obtained, it is possible to calculate the height equivalent of the theoretical plate (HETP) of the installation. A study is also made of 'sliding', a phenomenon peculiar to pulsed columns. The results obtained show that it is possible, using laboratory tests, to determine the characteristics and the operational condition of a moving-bed ion-exchange column. (author) [fr

  13. Study of resolution and linearity in LaBr3: Ce scintillator through digital-pulse processing

    International Nuclear Information System (INIS)

    Abhinav Kumar; Mishra, Gaurav; Ramachandran, K.

    2014-01-01

    Advent of digital pulse processing has led to a paradigm shift in pulse processing techniques by replacing analog electronics processing chain with equivalent algorithms acting on pulse profiles digitized at high sampling rates. In this paper, we have carried out offline digital pulse processing of Cerium-doped Lanthanum bromide scintillator (LaBr 3 : Ce) detector pulses, acquired using CAEN V1742 VME digitizer module. Algorithms have been written to approximate the functioning of peak sensing analog-to-digital convertor (ADC) and charge-to-digital convertor (QDC). Energy dependence of resolution and energy linearity of LaBr 3 : Ce scintillator detector has been studied by utilizing aforesaid algorithms

  14. Heat pulse propagation studies on DIII-D and the Tokamak Fusion Test Reactor

    Science.gov (United States)

    Fredrickson, E. D.; Austin, M. E.; Groebner, R.; Manickam, J.; Rice, B.; Schmidt, G.; Snider, R.

    2000-12-01

    Sawtooth phenomena have been studied on DIII-D and the Tokamak Fusion Test Reactor (TFTR) [D. Meade and the TFTR Group, in Proceedings of the International Conference on Plasma Physics and Controlled Nuclear Fusion, Washington, DC, 1990 (International Atomic Energy Agency, Vienna, 1991), Vol. 1, pp. 9-24]. In the experiments the sawtooth characteristics were studied with fast electron temperature (ECE) and soft x-ray diagnostics. For the first time, measurements of a strong ballistic electron heat pulse were made in a shaped tokamak (DIII-D) [J. Luxon and DIII-D Group, in Proceedings of the 11th International Conference on Plasma Physics and Controlled Nuclear Fusion Research, Kyoto (International Atomic Energy Agency, Vienna, 1987), Vol. 1, p. 159] and the "ballistic effect" was stronger than was previously reported on TFTR. Evidence is presented in this paper that the ballistic effect is related to the fast growth phase of the sawtooth precursor. Fast, 2 ms interval, measurements on DIII-D were made of the ion temperature evolution following sawteeth and partial sawteeth to document the ion heat pulse characteristics. It is found that the ion heat pulse does not exhibit the very fast, "ballistic" behavior seen for the electrons. Further, for the first time it is shown that the electron heat pulses from partial sawtooth crashes (on DIII-D and TFTR) are seen to propagate at speeds close to those expected from the power balance calculations of the thermal diffusivities whereas heat pulses from fishbones propagate at rates more consistent with sawtooth induced heat pulses. These results suggest that the fast propagation of sawtooth-induced heat pulses is not a feature of nonlinear transport models, but that magnetohydrodynamic events can have a strong effect on electron thermal transport.

  15. Study of intense pulse irradiation effects on silicon targets considered as ground matter for optical detectors

    International Nuclear Information System (INIS)

    Muller, O.

    1994-12-01

    This study aim was centered on morphological and structural alterations induced by laser irradiation on silicon targets considered as ground matter for optical detectors. First we recalled the main high light intensity effects on the condensed matter. Then we presented the experimental aspects. The experimental studies were achieved on two sample types: SiO 2 /Si and Si. Two topics were studied: the defect chronology according to wavelength and pulse length, and the crystalline quality as well as the structure defects of irradiated zones by Raman spectroscopy. Finally, irradiation of Si targets by intense pulsed beams may lead to material fusion. This phenomenon is particularly easy when the material is absorbent, when the pulse is short and when the material is superficially oxidized. (MML). 204 refs., 93 figs., 21 tabs., 1 appendix

  16. Assessment of anastomotic reliability with pulse oximetry in graded intestinal ischemia: an experimental study in dogs.

    Science.gov (United States)

    Türkyilmaz, Z; Sönmez, K; Başaklar, A C; Demiroğullari, B; Numanoğlu, V; Ekingen, G; Dursun, A; Altin, M A; Kale, N

    1997-12-01

    Pulse oximetry has been proposed as an appropriate and feasible technique in the assessment of intestinal ischemia in recent years. In this study the authors aimed to assess the reliability of anastomoses in the dog small intestine in which there is graded irreversible ischemia as measured by pulse oxymeter. In a control group of four dogs, without any devascularization, three small bowel anastomoses were formed in each dog. The study group consisted of 12 dogs. In each animal three intestinal segments with different levels of ischemia were created by ligating the marginal vessels proximally and distally in sequence beginning from the midpoint of the segmental vascular arcade. Preanastomotic pulse oximeter readings between 80% and 90% were assigned to mild ischemia, 70% and 80% to moderate, and 60% and 70% to severe ischemia group. Pulse oximetry measurements were obtained from probes applied to the antimesenteric serosal surfaces at the midpoint of small intestinal segments. A total of 48 intestinal segments (12 nonischemic in the control group and 36 with three different levels of ischemia in the study group) were transected in the midpoint and anastomosed in double layers. Postanastomotic SaO2 values were also noted. The anastomoses were evaluated 48 hours later macroscopically if there was any leakage, and biopsy specimens were obtained for histopathologic ischemic gradings. All results were studied statistically. Histopathologic grades between each group were statistically different (P .05), worsening as the level of ischemia increased. Pre- and postanastomotic pulse oximetry measurements correlated very well with the histological gradings (r = -0.90, P anastomoses) in severe ischemia groups. In the moderate ischemia group with an average preanastomotic pulse reading of 76.75%, each of the leaking anastomoses had a postanastomotic pulse measurement of lower than 70%. The finding that the difference between histopathologic grades of control and mild ischemia

  17. Pulse wave imaging in normal, hypertensive and aneurysmal human aortas in vivo: a feasibility study

    International Nuclear Information System (INIS)

    Li, Ronny X; Luo, Jianwen; Shahmirzadi, Danial; Konofagou, Elisa E; Balaram, Sandhya K; Chaudhry, Farooq A

    2013-01-01

    Arterial stiffness is a well-established biomarker for cardiovascular risk, especially in the case of hypertension. The progressive stages of an abdominal aortic aneurysm (AAA) have also been associated with varying arterial stiffness. Pulse wave imaging (PWI) is a noninvasive, ultrasound imaging-based technique that uses the pulse wave-induced arterial wall motion to map the propagation of the pulse wave and measure the regional pulse wave velocity (PWV) as an index of arterial stiffness. In this study, the clinical feasibility of PWI was evaluated in normal, hypertensive, and aneurysmal human aortas. Radiofrequency-based speckle tracking was used to estimate the pulse wave-induced displacements in the abdominal aortic walls of normal (N = 15, mean age 32.5 ± 10.2 years), hypertensive (N = 13, mean age 60.8 ± 15.8 years), and aneurysmal (N = 5, mean age 71.6 ± 11.8 years) human subjects. Linear regression of the spatio-temporal variation of the displacement waveform in the anterior aortic wall over a single cardiac cycle yielded the slope as the PWV and the coefficient of determination r 2 as an approximate measure of the pulse wave propagation uniformity. The aortic PWV measurements in all normal, hypertensive, and AAA subjects were 6.03 ± 1.68, 6.69 ± 2.80, and 10.54 ± 6.52 m s −1 , respectively. There was no significant difference (p = 0.15) between the PWVs of the normal and hypertensive subjects while the PWVs of the AAA subjects were significantly higher (p 2 in the AAA subjects was significantly lower (p 2 ) obtained using PWI, in addition to the PWI images and spatio-temporal maps that provide qualitative visualization of the pulse wave, may potentially provide valuable information for the clinical characterization of aneurysms and other vascular pathologies that regionally alter the arterial wall mechanics. (paper)

  18. An Experimental Study of Two-Phase Pulse Flushing Technology in Water Distribution Systems

    Directory of Open Access Journals (Sweden)

    Zhaozhao Tang

    2017-12-01

    Full Text Available The deterioration of drinking water during distribution process is caused by many factors. The microorganisms and substances peeling off from the “growth-ring” make the secondary pollution in drinking water distribution systems. To reduce the secondary pollution, two-phase pulse flushing technology is introduced to quickly remove the “growth-ring”. In this study, experiment is undertaken for investigating the efficiency of the two-phase pulse flushing and finding the best setting combination. A case study is undertaken to compare the efficiencies between the two-phase pulse and the single-phase flushing. The best setting combination of the two-phase pulse flushing is at the frequency 4 s–6 s (air inflow time is 4 s and air cut off time is 6 s and the round air inflow nozzle is set at the bottom of the pipe. Two-phase pulse flushing technology can save 95% of water and 6 h 40 min flushing time.

  19. Mathematical-model study of servo system with pulse-duration control of micromovements

    International Nuclear Information System (INIS)

    Dement'eva, M.A.; Leonov, A.P.; Popov, V.V.; Skugarevskii, A.I.; Ustinov, E.A.; Chernyavskii, N.N.

    1988-01-01

    A number of digital servo systems with pulse-duration control have been developed at the Institute of High Energy Physics for the instruments of the scanning and measurement system and various experimental setups. They are based on stock transistor bridge stages, whose loads are high-speed servomotors with printed-circuit armature windings. Study of these servo systems by traditional methods, which are based on Laplace transforms, or by mean values with expansion of the current pulse into a Fourier transform yields approximate results and does not reflect the actual processes that take place in a pulse servo system. They attempt to develop a method and extend it to the study of high-speed servo systems in the area of micromovements and quasistationary velocity without position or velocity feedback

  20. Numerical and experimental study of pulse-jet cleaning in fabric filters

    DEFF Research Database (Denmark)

    O. Andersen, B.; Nielsen, N. F.; Walther, J. H.

    2016-01-01

    Pulse-jet cleaning and understanding of the complex physics are essential when designing fabric filters used for air pollution control. Today, low-pressure cleaning is of particular interest due to demand for reduced compressed air consumption. Pulse-jet cleaned fabric filters have been studied......-pressure fabric filters (2 bar) is studied using a full three-dimensional (3D) CFD model. Experimental results obtained in a pilot-scale test filter with 28 bags, in length of 10 m and in general full-scale dimensions of the cleaning system are used to verify the reliability of the present CFD model....... The validated CFD model reveals the strong compressible effects, a highly transient behaviour, the formation of compressible vortex rings and the shock cell phenomenon within the overexpanded supersonic jet. The cleaning nozzles and venturi design aid or oppose the pulse-pressure within the bags, and this plays...

  1. Transient behaviour study program of research reactors fuel elements at the Hydra Pulse Reactor

    International Nuclear Information System (INIS)

    Khvostionov, V.E.; Egorenkov, P.M.; Malankin, P.V.

    2004-01-01

    Program on behavior study of research reactor Fuel Elements (FE) under transient regimes initiated by excessive reactivity insertion is being presented. Program would be realized at HYDRA pulse reactor at Russian Research Center 'Kurchatov Institute' (RRC 'K1'). HYDRA uses aqueous solution of uranyl sulfate (UO 2 SO 4 ) as a fuel. Up to 30 MJ of energy can be released inside the core during the single pulse, effective power pulse width varying from 2 to 10 ms. Reactor facility allows to investigate behaviour of FE consisting of different types of fuel composition, being developed according to Russian RERTR. First part of program is aimed at transient behaviour studying of FE MR, IRT-3M, WWR-M5 types containing meats based on dioxide uranium in aluminum matrix. Mentioned FEs use 90% and 36% enriched uranium. (author)

  2. Genome-wide association study identifies six new loci influencing pulse pressure and mean arterial pressure

    NARCIS (Netherlands)

    L.V. Wain (Louise); G.C. Verwoert (Germaine); P.F. O'Reilly (Paul); G. Shi (Gang); T. Johnson (Toby); M. Bochud (Murielle); K. Rice (Kenneth); P. Henneman (Peter); A.V. Smith (Albert Vernon); G.B. Ehret (Georg); N. Amin (Najaf); M.G. Larson (Martin); V. Mooser (Vincent); D. Hadley (David); M. Dörr (Marcus); J.C. Bis (Joshua); T. Aspelund (Thor); T. Esko (Tõnu); A.C.J.W. Janssens (Cécile); J.H. Zhao (Jing Hua); S.C. Heath (Simon); M. Laan (Maris); J. Fu (Jingyuan); G. Pistis (Giorgio); J. Luan; G. Lucas (Gavin); N. Pirastu (Nicola); I. Pichler (Irene); A.U. Jackson (Anne); R.J. Webster (Rebecca J.); F.F. Zhang; J. Peden (John); R. Schmidt (Reinhold); T. Tanaka (Toshiko); H. Campbell (Harry); W. Igl (Wilmar); Y. Milaneschi (Yuri); J.J. Hottenga (Jouke Jan); V. Vitart (Veronique); D.I. Chasman (Daniel); S. Trompet (Stella); J.L. Bragg-Gresham (Jennifer L.); B.Z. Alizadeh (Behrooz); J.C. Chambers (John); X. Guo (Xiuqing); T. Lehtimäki (Terho); B. Kuhnel (Brigitte); L.M. Lopez; O. Polasek (Ozren); M. Boban (Mladen); C.P. Nelson (Christopher P.); A.C. Morrison (Alanna); V. Pihur (Vasyl); S.K. Ganesh (Santhi); A. Hofman (Albert); S. Kundu (Suman); F.U.S. Mattace Raso (Francesco); F. Rivadeneira Ramirez (Fernando); E.J.G. Sijbrands (Eric); A.G. Uitterlinden (André); S.J. Hwang; R.S. Vasan (Ramachandran Srini); Y.A. Wang (Ying); S.M. Bergmann (Sven); P. Vollenweider (Peter); G. Waeber (Gérard); J. Laitinen (Jaana); A. Pouta (Anneli); P. Zitting (Paavo); W.L. McArdle (Wendy); H.K. Kroemer (Heyo); U. Völker (Uwe); H. Völzke (Henry); N.L. Glazer (Nicole); K.D. Taylor (Kent); T.B. Harris (Tamara); H. Alavere (Helene); T. Haller (Toomas); A. Keis (Aime); M.L. Tammesoo; Y.S. Aulchenko (Yurii); K-T. Khaw (Kay-Tee); P. Galan (Pilar); S. Hercberg (Serge); G.M. Lathrop (Mark); S. Eyheramendy (Susana); E. Org (Elin); S. Sõber (Siim); X. Lu (Xiaowen); I.M. Nolte (Ilja); B.W.J.H. Penninx (Brenda); T. Corre (Tanguy); C. Masciullo (Corrado); C. Sala (Cinzia); L. Groop (Leif); B.F. Voight (Benjamin); O. Melander (Olle); C.J. O'Donnell (Christopher); V. Salomaa (Veikko); P. d' Adamo (Pio); A. Fabretto (Antonella); F. Faletra (Flavio); S. Ulivi (Shelia); F. Del Greco M (Fabiola); M.F. Facheris (Maurizio); F.S. Collins (Francis); R.N. Bergman (Richard); J.P. Beilby (John); J. Hung (Judy); A.W. Musk (Arthur); M. Mangino (Massimo); S.Y. Shin (So Youn); N. Soranzo (Nicole); H. Watkins (Hugh); A. Goel (Anuj); A. Hamsten (Anders); P. Gider (Pierre); M. Loitfelder (Marisa); M. Zeginigg (Marion); D.G. Hernandez (Dena); S.S. Najjar (Samer); P. Navarro (Pau); S.H. Wild (Sarah); A.M. Corsi (Anna Maria); A. Singleton (Andrew); E.J.C. de Geus (Eco); G.A.H.M. Willemsen (Gonneke); A.N. Parker (Alex); L.M. Rose (Lynda); B.M. Buckley (Brendan M.); D.J. Stott (David. J.); M. Orrù (Marco); M. Uda (Manuela); M.M. van der Klauw (Melanie); X. Li (Xiaohui); J. Scott (James); Y.D.I. Chen (Yii-Der Ida); G.L. Burke (Greg); M. Kähönen (Mika); J. Viikari (Jorma); A. Döring (Angela); T. Meitinger (Thomas); G.S. Davis; J.M. Starr (John); V. Emilsson (Valur); A.S. Plump (Andrew); J.H. Lindeman (Jan H.); P.A.C. 't Hoen (Peter); I.R. König (Inke); J.F. Felix (Janine); R. Clarke; J. Hopewell; H. Ongen (Halit); M.M.B. Breteler (Monique); S. Debette (Stéphanie); A.L. DeStefano (Anita); M. Fornage (Myriam); G.F. Mitchell (Gary); H. Holm (Hilma); K. Stefansson (Kari); G. Thorleifsson (Gudmar); U. Thorsteinsdottir (Unnur); N.J. Samani (Nilesh); M. Preuss (Michael); I. Rudan (Igor); C. Hayward (Caroline); I.J. Deary (Ian); H.E. Wichmann (Heinz Erich); O. Raitakari (Olli); W. Palmas (Walter); J.S. Kooner (Jaspal); R.P. Stolk (Ronald); J.W. Jukema (Jan Wouter); A.F. Wright (Alan); D.I. Boomsma (Dorret); S. Bandinelli (Stefania); U. Gyllensten (Ulf); J.F. Wilson (James); L. Ferrucci (Luigi); M. Farrall (Martin); T.D. Spector (Timothy); L.J. Palmer; J. Tuomilehto (Jaakko); A. Pfeufer (Arne); P. Gasparini (Paolo); D.S. Siscovick (David); D. Altshuler (David); R.J.F. Loos (Ruth); D. Toniolo (Daniela); H. Snieder (Harold); C. Gieger (Christian); P. Meneton (Pierre); N.J. Wareham (Nick); B.A. Oostra (Ben); A. Metspalu (Andres); L.J. Launer (Lenore); R. Rettig (Rainer); D.P. Strachan (David); J.S. Beckmann (Jacques); J.C.M. Witteman (Jacqueline); J.A.P. Willems van Dijk (Ko); E.A. Boerwinkle (Eric); M. Boehnke (Michael); P.M. Ridker (Paul); M.R. Järvelin; A. Chakravarti (Aravinda); J. Erdmann (Jeanette); V. Gudnason (Vilmundur); C. Newton-Cheh (Christopher); D. Levy (Daniel); P. Arora (Pankaj); P. Munroe (Patricia); B.M. Psaty (Bruce); M. Caulfield (Mark); D.C. Rao (Dabeeru C.); P. Elliott (Paul); P. Tikka-Kleemola (Päivi); G.R. Abecasis (Gonçalo); I.E. Barroso (Inês)

    2011-01-01

    textabstractNumerous genetic loci have been associated with systolic blood pressure (SBP) and diastolic blood pressure (DBP) in Europeans. We now report genome-wide association studies of pulse pressure (PP) and mean arterial pressure (MAP). In discovery (N = 74,064) and follow-up studies (N =

  3. Competition for pulsed resources: an experimental study of establishment and coexistence for an arid-land grass.

    Science.gov (United States)

    Jankju-Borzelabad, Mohammad; Griffiths, Howard

    2006-07-01

    In arid environments, episodically-pulsed resources are important components of annual water and nutrient supply for plants. This study set out to test whether seedlings have an increased capacity for using pulsed resources, which might then improve establishment when in competition with older individuals. A second aim was to determine whether there is a trade-off in competitive strategies when resources are supplied continuously at low concentrations, or as pulses with pronounced inter-pulse periods. A glasshouse experiment used a target-neighbour design of size-asymmetric competition, with juveniles of Panicum antidotale (blue panicgrass) introduced into contrasting densities of adult plants. Stable isotopes of nitrogen were used for measuring plant resource uptake from pulses, and tolerance to inter-pulse conditions was assessed as the mean residence time (MRT) of nitrogen. A higher root/shoot ratio and finer root system enhanced the capacity of juveniles to use resources when pulsed, rather than when continuously supplied. Higher resource uptake during pulses improved the establishment of juvenile Panicum in mixed cultures with older individuals. However, a trade-off was observed in plant strategies, with juveniles showing a lower MRT for nitrogen, which suggested reduced tolerance to resource deficit during inter-pulse periods. Under field conditions, higher utilization of pulsed resources would lead to the improved seedling establishment of Panicum adjacent to "nurse" plants, whereas mature plants with well-developed roots, exploiting a greater soil volume, maintain more constant resource uptake and retention during inter-pulse periods.

  4. A pulsed source neutron reflectometer for surface studies

    International Nuclear Information System (INIS)

    Penfold, J.; Williams, W.G.

    1985-05-01

    A design for a neutron reflectometer for surface studies to be constructed at the SNS is presented. Examples of its use to study problems in surface chemistry, surface magnetism and low dimensional structures are highlighted. (author)

  5. Shock wave generation in laser ablation studied using pulsed digital holographic interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Amer, Eynas; Gren, Per; Sjoedahl, Mikael [Division of Experimental Mechanics, Luleaa University of Technology, SE-971 87 Luleaa (Sweden)], E-mail: eynas.amer@ltu.se, E-mail: per.gren@ltu.se, E-mail: mikael.sjodahl@ltu.se

    2008-11-07

    Pulsed digital holographic interferometry has been used to study the shock wave induced by a Q-switched Nd-YAG laser ({lambda} = 1064 nm and pulse duration 12 ns) on a polycrystalline boron nitride (PCBN) ceramic target under atmospheric air pressure. A special setup based on using two synchronized wavelengths from the same laser for processing and measurement simultaneously has been introduced. Collimated laser light ({lambda} = 532 nm) passed through the volume along the target and digital holograms were recorded for different time delays after processing starts. Numerical data of the integrated refractive index field were calculated and presented as phase maps showing the propagation of the shock wave generated by the process. The location of the induced shock wave front was observed for different focusing and time delays. The amount of released energy, i.e. the part of the incident energy of the laser pulse that is eventually converted to a shock wave has been estimated using the point explosion model. The released energy is normalized by the incident laser pulse energy and the energy conversion efficiency between the laser pulse and PCBN target has been calculated at different power densities. The results show that the energy conversion efficiency seems to be constant around 80% at high power densities.

  6. Measurement of carboxyhemoglobin and methemoglobin by pulse oximetry: a human volunteer study.

    Science.gov (United States)

    Barker, Steven J; Curry, Jeremy; Redford, Daniel; Morgan, Scott

    2006-11-01

    A new eight-wavelength pulse oximeter is designed to measure methemoglobin and carboxyhemoglobin, in addition to the usual measurements of hemoglobin oxygen saturation and pulse rate. This study examines this device's ability to measure dyshemoglobins in human volunteers in whom controlled levels of methemoglobin and carboxyhemoglobin are induced. Ten volunteers breathed 500 ppm carbon monoxide until their carboxyhemoglobin levels reached 15%, and 10 different volunteers received intravenous sodium nitrite, 300 mg, to induce methemoglobin. All were instrumented with arterial cannulas and six Masimo Rad-57 (Masimo Inc., Irvine, CA) pulse oximeter sensors. Arterial blood was analyzed by three laboratory CO-oximeters, and the resulting carboxyhemoglobin and methemoglobin measurements were compared with the corresponding pulse oximeter readings. The Rad-57 measured carboxyhemoglobin with an uncertainty of +/-2% within the range of 0-15%, and it measured methemoglobin with an uncertainty of 0.5% within the range of 0-12%. The Masimo Rad-57 is the first commercially available pulse oximeter that can measure methemoglobin and carboxyhemoglobin, and it therefore represents an expansion of our oxygenation monitoring capability.

  7. Studies of nanosecond pulse surface ionization wave discharges over solid and liquid dielectric surfaces

    International Nuclear Information System (INIS)

    Petrishchev, Vitaly; Leonov, Sergey; Adamovich, Igor V

    2014-01-01

    Surface ionization wave discharges generated by high-voltage nanosecond pulses, propagating over a planar quartz surface and over liquid surfaces (distilled water and 1-butanol) have been studied in a rectangular cross section test cell. The discharge was initiated using a custom-made, alternating polarity, high-voltage nanosecond pulse plasma generator, operated at a pulse repetition rate of 100–500 Hz, with a pulse peak voltage and current of 10–15 kV and 7–20 A, respectively, a pulse FWHM of ∼100 ns, and a coupled pulse energy of 2–9 mJ/pulse. Wave speed was measured using a capacitive probe. ICCD camera images demonstrated that the ionization wave propagated predominantly over the quartz wall or over the liquid surface adjacent to the grounded waveguide placed along the bottom wall of the test cell. Under all experimental conditions tested, the surface plasma ‘sheet’ was diffuse and fairly uniform, both for positive and negative polarities. The parameters of ionization wave discharge propagating over distilled water and 1-butanol surfaces were close to those of the discharge over a quartz wall. No perturbation of the liquid surface by the discharge was detected. In most cases, the positive polarity surface ionization wave propagated at a higher speed and over a longer distance compared to the negative polarity wave. For all three sets of experiments (surface ionization wave discharge over quartz, water and 1-butanol), wave speed and travel distance decreased with pressure. Diffuse, highly reproducible surface ionization wave discharge was also observed over the liquid butanol–saturated butanol vapor interface, as well as over the distilled water–saturated water vapor interface, without buffer gas flow. No significant difference was detected between surface ionization discharges sustained using single-polarity (positive or negative), or alternating polarity high-voltage pulses. Plasma emission images yielded preliminary evidence of charge

  8. Simulation study on cross polarization scattering of ultrashort-pulse electromagnetic waves

    International Nuclear Information System (INIS)

    Katsuragawa, Naoki; Hojo, Hitoshi; Mase, Atushi

    1996-11-01

    Simulation study on cross polarization scattering of ultrashort-pulse electromagnetic waves due to magnetic fluctuations is presented. One-dimensional coupled wave equations for the ordinary and extraordinary modes are solved for incident unipolar sub-cycle pulses in an inhomogeneous magnetized plasma. It is shown that the peak frequencies in the frequency-spectral signals of the mode-converted reflected waves are determined from the Bragg resonance condition in the wave numbers of the ordinary mode, the extraordinary mode and the magnetic fluctuations for relatively short-wavelength localized magnetic fluctuations. (author)

  9. Comparative study of pulsed and steady-state tokamak reactor burn cycles

    International Nuclear Information System (INIS)

    Ehst, D.A.; Brooks, J.N.; Cha, Y.; Evans, K.; Hassanein, A.M.; Kim, S.; Majumdar, S.; Misra, B.; Stevens, H.C.

    1984-05-01

    Four distinct operating modes have been proposed for tokamaks. Our study focuses on capital costs and lifetime limitations of reactor subsystems in an attempt to quantify sensitivity to pulsed operation. Major problem areas considered include: thermal fatigue on first wall, limiter/divertor; thermal energy storage; fatigue in pulsed poloidal field coils; out-of-plant fatigue and eddy current heating in toroidal field coils; electric power supply costs; and noninductive driver costs. We assume a high availability and low cost of energy will be mandatory for a commercial fusion reactor, and we characterize improvements in physics and engineering which will help achieve these goals for different burn cycles

  10. Parameter studies on the effect of pulse shape on the dynamic plastic deformation of a hexagon

    International Nuclear Information System (INIS)

    Youngdahl, C.K.

    1973-10-01

    Results of a parameter study on the dynamic plastic response of a hexagonal subassembly duct subjected to an internal pressure pulse of arbitrary shape are presented. Plastic distortion of the cross section and large-deformation geometric effects that result in redistribution of the internal forces between bending and membrane stresses in the hexagon wall are included in the analytical model. Correlation procedures are established for relating permanent plastic deformation to simple properties of the pressure pulse, for both the small- and large-deformation ranges. Characteristic response times are determined, and the dynamic load factor for large-deformation plastic response is computed

  11. [The development of a wearable pulse oximeter sensor and study of the calibration method].

    Science.gov (United States)

    Wu, Xiaoling; Cai, Guiyan

    2009-08-01

    The paper first analyses the principles of measurement of the two-wave oximeter and their limitations in technology. We propose to filter off motion interference from pulse oximeter signal using an algorithm based on the Beer-Lambert law that requires a three-wave probe (660 nm, 850 nm, and 940 nm). Based on the new algorithm, this paper describes the design principle of the circuitry and the software flowchart. Also, we study the calibration method of the pulse oximeter sensor and discuss the results in this paper.

  12. Experimental study and numerical simulation of free pulsed jets; Etude experimentale et modelisation numerique des jets libres pulses

    Energy Technology Data Exchange (ETDEWEB)

    Marzouk, Salwa; Mhiri, Hatem [Ecole Nationale d' Ingenieurs de Monastir, Lab. de Mecanique des Fluides et Thermique, Monastir (Tunisia); Caminat, Ph.; Le Palec, G.; Bournot, Ph. [UNIMECA, 13 - Marseille (France)

    2001-07-01

    A plane pulsed jet flow has been simulated by a finite difference method. Experimental results have also been obtained by laser tomography and particle image velocimetry. The results show that the flow is affected by the pulsation in the vicinity of the nozzle to reach an asymptotic state of a permanent jet. (A.L.B.)

  13. Relaxation and crystallization of amorphous carbamazepine studied by terahertz pulsed spectroscopy

    DEFF Research Database (Denmark)

    Zeitler, J Axel; Taday, Philip F; Pepper, Michael

    2007-01-01

    At the example of carbamazepine the crystallization of a small organic molecule from its amorphous phase was studied using in situ variable temperature terahertz pulsed spectroscopy (TPS). Even though terahertz spectra of disordered materials in the glassy state exhibit no distinct spectral featu...

  14. Local electronic structure of TM-based alloys: a pulsed NMR study

    International Nuclear Information System (INIS)

    Guerra, D.A.

    1984-01-01

    A pulsed NMR study on several transition metal + metalloid amorphous alloys is reported. The analisis of Knight shifts and nuclear spin-lattice relaxation of metalloids indicates a dominant contribution of p-electrons in the Fermi level density of state, supporting the existence of a p-d hibridization. (author) [pt

  15. Experimental studies on pulse soft X-ray generator

    International Nuclear Information System (INIS)

    Li Chengrong; Yang Qinchi; Luo Chengmu; Han Min

    1990-01-01

    Emission sources of soft x rays (2 keV < hv < 6 keV) from hot plasmas have been studied in a small gas-puff Z-pinch. The emission sources are a group of uncontinuous hot spots. The output of soft x rays from the hot spots have been measured and the effect of the initial gas density on the yield of soft x rays has been investigated

  16. Pulse radiolysis study on oxidation reactions of gallic acid

    International Nuclear Information System (INIS)

    Dwibedy, P.; Dey, G.R.; Naik, D.B.; Kishore, Kamal

    1998-01-01

    Reactions of OH . /O - and other oxidising radicals viz. N 3 . , Br 2 .- , Cl 2 .- with gallic acid (GA) have been studied at various pHs. At pH 6.8, OH . radicals react with GA giving an adduct which in turn reacts with the parent GA to give a dimeric species. At pH 9.7, the initial OH adduct formed is able to oxidize GA to give a semi-oxidised species. At pH 12 and ∼ 13.6, OH . /O .- radicals directly bring about oxidation of GA. (author)

  17. A pulse radiolytic study of some radiosensitizing and radioprotective substances

    International Nuclear Information System (INIS)

    Sjoeberg, L.

    1981-01-01

    The one-electron reduction potentials for substituted nitroimidazoles and nitrobenzenes in aqueous solution have been correlated to their electron affinities calculated by the semiempirical quantum mechanical method HAM/3. This procedure implies the validity of a Hammet like equation for the substances studied. Glutathione has been shown to compete with oxygen for radiation induced radicals. Hence the reaction of the hydroxyl radical with glutathione in neutral and alkaline aqueous solution was investigated in some detail. A reaction scheme involving a pH dependent formation of thiyl, and carbon centered radicals is given. (Auth.)

  18. Mechanisms of CFR composites destruction studying with pulse acoustic microscopy

    Science.gov (United States)

    Petronyuk, Y. S.; Morokov, E. S.; Levin, V. M.; Ryzhova, T. B.; Chernov, A. V.

    2016-05-01

    Non-destructive inspection of carbon-fiber-reinforced (CFR) composites applied in aerospace industry attracts a wide attention. In the paper, high frequency focused ultrasound (50-100 MHz) has been applied to study the bulk microstructure of the CFR material and mechanisms of its destruction under the mechanical loading. It has been shown impulse acoustic microscopy provides detecting the areas of adhesion loss at millimeter and micron level. Behavior of the CFR laminate structure fabricated by prepreg or infusion technology has been investigated under the tensile and impact loading.

  19. Study on the dynamic holdup distribution of the pulsed extraction column

    International Nuclear Information System (INIS)

    Wang, S.; Chen, J.; Wu, Q.

    2013-01-01

    In the study, a CSTR cascade dynamic hydraulic model was developed to investigate the dynamic holdup distribution of the pulsed extraction column. It is assumed that the dynamic process of the dispersed phase holdup of pulsed extraction column has equal effects with the operational process of multiple cascade CSTRs. The process is consistent with the following assumptions: the holdups vary on different stages but maintain uniform on each stage; the changes of the hydraulic parameters have impact initially on the inlet of dispersed phase, and stability will be reached gradually through stage-by-stage blending. The model was tested and verified utilizing time domain response curves of the average holdup. Nearly 150 experiments were carried out with different capillary columns, various feed liquids, and diverse continuous phases and under different operation conditions. The regression curves developed by the model show a good consistency with the experimental results. After linking parameters of the model with operational conditions, the study further found that the parameters are only linearly correlated with pulse conditions and have nothing to do with flow rate for a specific pulsed extraction column. The accuracy of the model is measured by the average holdup, and the absolute error is ±0.01. The model can provide supports for the boundary studies on hydraulics and mass transfer by making simple and reliable prediction of the dynamic holdup distribution, with relatively less accessible hydraulic experimental data. (authors)

  20. Study on the dynamic holdup distribution of the pulsed extraction column

    Energy Technology Data Exchange (ETDEWEB)

    Wang, S.; Chen, J.; Wu, Q. [Tsinghua University, Beijing 100084 (China)

    2013-07-01

    In the study, a CSTR cascade dynamic hydraulic model was developed to investigate the dynamic holdup distribution of the pulsed extraction column. It is assumed that the dynamic process of the dispersed phase holdup of pulsed extraction column has equal effects with the operational process of multiple cascade CSTRs. The process is consistent with the following assumptions: the holdups vary on different stages but maintain uniform on each stage; the changes of the hydraulic parameters have impact initially on the inlet of dispersed phase, and stability will be reached gradually through stage-by-stage blending. The model was tested and verified utilizing time domain response curves of the average holdup. Nearly 150 experiments were carried out with different capillary columns, various feed liquids, and diverse continuous phases and under different operation conditions. The regression curves developed by the model show a good consistency with the experimental results. After linking parameters of the model with operational conditions, the study further found that the parameters are only linearly correlated with pulse conditions and have nothing to do with flow rate for a specific pulsed extraction column. The accuracy of the model is measured by the average holdup, and the absolute error is ±0.01. The model can provide supports for the boundary studies on hydraulics and mass transfer by making simple and reliable prediction of the dynamic holdup distribution, with relatively less accessible hydraulic experimental data. (authors)

  1. In vivo study of human skin using pulsed terahertz radiation

    International Nuclear Information System (INIS)

    Pickwell, E; Cole, B E; Fitzgerald, A J; Pepper, M; Wallace, V P

    2004-01-01

    Studies in terahertz (THz) imaging have revealed a significant difference between skin cancer (basal cell carcinoma) and healthy tissue. Since water has strong absorptions at THz frequencies and tumours tend to have different water content from normal tissue, a likely contrast mechanism is variation in water content. Thus, we have previously devised a finite difference time-domain (FDTD) model which is able to closely simulate the interaction of THz radiation with water. In this work we investigate the interaction of THz radiation with normal human skin on the forearm and palm of the hand in vivo. We conduct the first ever systematic in vivo study of the response of THz radiation to normal skin. We take in vivo reflection measurements of normal skin on the forearm and palm of the hand of 20 volunteers. We compare individual examples of THz responses with the mean response for the areas of skin under investigation. Using the in vivo data, we demonstrate that the FDTD model can be applied to biological tissue. In particular, we successfully simulate the interaction of THz radiation with the volar forearm. Understanding the interaction of THz radiation with normal skin will form a step towards developing improved imaging algorithms for diagnostic detection of skin cancer and other tissue disorders using THz radiation

  2. In vivo study of human skin using pulsed terahertz radiation

    Energy Technology Data Exchange (ETDEWEB)

    Pickwell, E [Semiconductor Physics Group, Cavendish Laboratory, Cambridge University, Madingley Road, Cambridge CB3 0HE (United Kingdom); Cole, B E [TeraView Ltd, Unit 302/4 Cambridge Science Park, Cambridge CB4 0WG (United Kingdom); Fitzgerald, A J [TeraView Ltd, Unit 302/4 Cambridge Science Park, Cambridge CB4 0WG (United Kingdom); Pepper, M [Semiconductor Physics Group, Cavendish Laboratory, Cambridge University, Madingley Road, Cambridge CB3 0HE (United Kingdom); Wallace, V P [TeraView Ltd, Unit 302/4 Cambridge Science Park, Cambridge CB4 0WG (United Kingdom)

    2004-05-07

    Studies in terahertz (THz) imaging have revealed a significant difference between skin cancer (basal cell carcinoma) and healthy tissue. Since water has strong absorptions at THz frequencies and tumours tend to have different water content from normal tissue, a likely contrast mechanism is variation in water content. Thus, we have previously devised a finite difference time-domain (FDTD) model which is able to closely simulate the interaction of THz radiation with water. In this work we investigate the interaction of THz radiation with normal human skin on the forearm and palm of the hand in vivo. We conduct the first ever systematic in vivo study of the response of THz radiation to normal skin. We take in vivo reflection measurements of normal skin on the forearm and palm of the hand of 20 volunteers. We compare individual examples of THz responses with the mean response for the areas of skin under investigation. Using the in vivo data, we demonstrate that the FDTD model can be applied to biological tissue. In particular, we successfully simulate the interaction of THz radiation with the volar forearm. Understanding the interaction of THz radiation with normal skin will form a step towards developing improved imaging algorithms for diagnostic detection of skin cancer and other tissue disorders using THz radiation.

  3. Pulse radiolysis study of one electron oxidation of riboflavin

    International Nuclear Information System (INIS)

    Kishore, K.; Moorthy, P.N.; Guha, S.N.

    1991-01-01

    One electron oxidation of riboflavin (Rf) has been studied using various oxidising species such as Cl 2 -. , SO 4 -. and OH radicals. The transient species produced by the reaction of SO 4 -. with riboflavin gave spectra with λ m at 680 and 640 nm at pHs 4 and 7.1 respectively with a pK a at ∼ 6. Cl 2 -. radicals reacted with riboflavin to give a transient spectrum with λ m at 570 nm. The possibility of two sites viz. C-8 methyl group and the extended π-ring system of the molecule for oxidation reaction are discussed. The reaction of Cl 2 -. with riboflavin is an equilibrium from which the redox potential for the Rf +. /Rf couple has been evaluated to be 2.28 V vs NHE. OH radicals reacted with riboflavin to give a transient spectrum attributable to a mixture of species produced by addition or abstraction reactions. (author)

  4. [Autoaggression and pulse rate--a longitudinal study].

    Science.gov (United States)

    Rohmann, U H; Elbing, U; Hartmann, H

    1988-12-01

    This article presents a model of autoaggressive behavior in which a distinction is made between determining and maintaining factors. Specific environmental, in particular social, and organismic variables are linked to them. The two types of variables interact, thus causing or maintaining autoaggressive behavior. A theory of autoaggression must therefore rely on multicausal/multimodal explanations. A connection between autoaggression and a high level of arousal suggests itself. In this single-case longitudinal study a comparison was made between heart rate and frequency of autoaggressive behavior. High heart rates were found to be correlated with low frequencies of autoaggressive behavior and vice versa. Decreasing autoaggressive behavior was coupled with increasing muscle relaxation and increasing motor activity. However, abnormally high heart rates were associated with both low and high levels of motor activity.

  5. Material studies for pulsed high-intensity proton beam targets

    International Nuclear Information System (INIS)

    Simos, N.; Kirk, H.; Ludewig, H.; Thieberger, P.; Weng, W-T.; McDonald, K.; Yoshimura, K.

    2004-01-01

    Intense beams for muon colliders and neutrino facilities require high-performance target stations of 1-4 MW proton beams. The physics requirements for such a system push the envelope of our current knowledge as to how materials behave under high-power beams for both short and long exposure. The success of an adopted scheme that generates, captures and guides secondary particles depends on the useful life expectancy of this critical system. This paper presents an overview of what has been achieved during the various phases of the experimental effort including a tentative plan to continue the effort by expanding the material matrix. The first phase of the project was to study the changes after irradiation in mechanical properties and specially in thermal expansion coefficient of various materials. During phase-I the study attention was primarily focused on Super-invar and in a lesser degree on Inconel-718. Invar is a metal alloy which predominantly consists of 62% Fe, 32% Ni and 5% Co. It is showed that this metal, whose non-irradiated properties held such promise, can only be considered a serious target candidate for an intense proton beam only if one can anneal the atomic displacements followed by the appropriate heat treatment to restore its favorable expansion coefficient. New materials that have been developed for various industrial needs by optimizing key properties, might be of value for the accelerator community. These materials like carbon-carbon composites, titanium alloys, the Toyota 'gum metal', the Vascomax material and the AlBeMet alloy will be explored and tested in the second phase of the project. (A.C.)

  6. Redox reactions of methylene blue: a pulse radiolysis study

    International Nuclear Information System (INIS)

    Kishore, K.; Guha, S.N.; Mahadevan, J.; Moorthy, P.N.; Mittal, J.P.

    1989-01-01

    One-electron oxidation of methylene blue (MB - has been studied using specific oxidizing radicals such as Cl 2 - , Br 2 - , N 3 and Tl(II) in acidic and neutral aqueous solutions). The transient spectrum showed absorption maxima at 525 nm and 360 nm in the acidic pH region. At neutral pH also the absorption maxima were at 525 and 360 nm but the extinction coefficients were lower by 30%. A pK a of ∼4.3 was observed for the equilibrium MBH 3+ MB 2+ + H + . In the case of N 3 radical as the oxidant, the equilibrium: N 3 + MB = N 3 - + MB 2+ was observed for which an equilibrium constant of 120 was estimated from the experimental data. From this as well as from cyclic voltammetric experiments, the redox potential for the MB 2+ /MB + couple was calculated as 1.25 V vs NHE. The transient species produced by the reaction of OH radicals with methylene blue gave a very different spectrum with λ m = 400nm and a pK a of ∼ 8.6, and hence it is inferred that OH radicals do not bring about one-electron oxidation of the molecule. (author)

  7. Pulse radiolysis study of zinc(II)-insulin

    Energy Technology Data Exchange (ETDEWEB)

    Elliot, A J; Wilkinson, F; Armstrong, D A [Calgary Univ., Alberta (Canada). Dept. of Chemistry

    1980-07-01

    Reactions of e/sup -/sub(aq) with zinc(II)-insulin at pH 6.6 and 9.0 yielded relatively low disulphide anion absorptions, suggesting e/sup -/sub(aq) reacts at other sites than S-S. A similar conclusion was reached for the reaction of COsub(./2) where an even lower yield of disulphide anion was found. However, here the disulphide anion yield increased with 'prepulsing'. Simultaneously the rate constant decreased, implying that a more reactive site was 'cleaned up'. While no reaction of Brsub(./2) with insulin was observed, both OH and Clsub(./2) reacted rapidly and predominantly at the tyrosine residues. The second order rate constants, calculated in terms of insulin monomer concentrations, are reported for e/sup -/sub(aq) COsub(./2) and Clsub(./2). The transient spectra qualitatively support evidence regarding the accessibility of S-S bonds and tyrosine residues in the various forms of insulin as predicted from earlier studies.

  8. Study on the flow nonuniformity in a high capacity Stirling pulse tube cryocooler

    Science.gov (United States)

    You, X.; Zhi, X.; Duan, C.; Jiang, X.; Qiu, L.; Li, J.

    2017-12-01

    High capacity Stirling-type pulse tube cryocoolers (SPTC) have promising applications in high temperature superconductive motor and gas liquefaction. However, with the increase of cooling capacity, its performance deviates from well-accepted one-dimensional model simulation, such as Sage and Regen, mainly due to the strong field nonuniformity. In this study, several flow straighteners placed at both ends of the pulse tube are investigated to improve the flow distribution. A two-dimensional model of the pulse tube based on the computational fluid dynamics (CFD) method has been built to study the flow distribution of the pulse tube with different flow straighteners including copper screens, copper slots, taper transition and taper stainless slot. A SPTC set-up which has more than one hundred Watts cooling power at 80 K has been built and tested. The flow straighteners mentioned above have been applied and tested. The results show that with the best flow straightener the cooling performance of the SPTC can be significantly improved. Both CFD simulation and experiment show that the straighteners have impacts on the flow distribution and the performance of the high capacity SPTC.

  9. Study on the E-beam pulse width scaling for a 25-kilojoule KrF amplifier

    International Nuclear Information System (INIS)

    Ramirez, J.J.

    1983-02-01

    The KrF laser is being considered as an ICF driver candidate. Since this laser is not an energy storing system, the output energy of an amplifier is delivered over the entire pulse width of the excitation source. E-beam pumping is preferred for large energy systems. The e-beam pulse width is constrained to a few hundred nanoseconds by laser operation and pulsed power considerations. The target requires pulses of a few nanoseconds. Angular multiplexing of probe beams through the amplifier is a preferred scheme for bridging this difference in timing requirements. Progressively shorter target irradiation times may be obtained by using shorter pulse probe beams and by either increasing the number of angular multiplexed beams or by decreasing the e-beam pulse width. This report documents results of a study on the consequences of following the latter approach

  10. Study of Pulsed vs. RF Plasma Properties for Surface Processing Applications

    Science.gov (United States)

    Tang, Ricky; Hopkins, Matthew; Barnat, Edward; Miller, Paul

    2015-09-01

    The ability to manipulate the plasma parameters (density, E/N) was previously demonstrated using a double-pulsed column discharge. Experiments extending this to large-surface plasmas of interest to the plasma processing community were conducted. Differences between an audio-frequency pulsed plasma and a radio-frequency (rf) discharge, both prevalent in plasma processing applications, were studied. Optical emission spectroscopy shows higher-intensity emission in the UV/visible range for the pulsed plasma comparing to the rf plasma at comparable powers. Data suggest that the electron energy is higher for the pulsed plasma leading to higher ionization, resulting in increased ion density and ion flux. Diode laser absorption measurements of the concentration of the 1S5 metastable and 1S4 resonance states of argon (correlated with the plasma E/N) provide comparisons between the excitation/ionization states of the two plasmas. Preliminary modeling efforts suggest that the low-frequency polarity switch causes a much more abrupt potential variation to support interesting transport phenomena, generating a ``wave'' of higher temperature electrons leading to more ionization, as well as ``sheath capture'' of a higher density bolus of ions that are then accelerated during polarity switch.

  11. Studies of pulsed laser melting and rapid solidification using amorphous silicon

    International Nuclear Information System (INIS)

    Lowndes, D.H.; Wood, R.F.

    1984-06-01

    Pulsed-laser melting of ion implantation-amorphized silicon layers, and subsequent solidification were studied. Measurements of the onset of melting of amorphous silicon layers and of the duration of melting, and modified melting model calculations demonstrated that the thermal conductivity, K/sub a/, of amorphous silicon is very low (K/sub a/ approx. = 0.02 W/cm-K). K/sub a/ is also the dominant parameter determining the dynamical response of amorphous silicon to pulsed laser radiation. TEM indicates that bulk (volume) nucleation occurs directly from the highly undercooled liquid silicon that can be prepared by pulsed laser melting of amorphous silicon layers at low laser energy densities. A modified thermal melting model is presented. The model calculations demonstrate that the release of latent heat by bulk nucleation occurring during the melt-in process is essential to obtaining agreement with observed depths of melting. These calculations also show that this release of latent heat accompanying bulk nucleation can result in the existence of buried molten layers of silicon in the interior of the sample after the surface has solidified. The bulk nucleation implies that the liquid-to-amorphous phase transition (produced using picosecond or uv nanosecond laser pulses) cannot be explained using purely thermodynamic considerations

  12. Retrieval process development and enhancements FY96 pulsed-air mixer testing and deployment study

    International Nuclear Information System (INIS)

    Powell, M.R.; Hymas, C.R.

    1996-08-01

    Millions of gallons of radioactive wastes resides in underground tanks at US Department of Energy sites. The waste was generated primarily by the processing of nuclear fuel elements to remove fissile radionuclides for use in atomic weapons. Plans call for the waste to be removed from the tanks and processed to create immobile waste forms, which will be stored to prevent release to the environment. The consistency of the waste ranges from liquid, to slurry, to sticky sludge, to hard saltcake. a variety of waste- retrieval and processing methods are being evaluated and implemented. One such method is pulsed-air mixing, which is the subject of this report. Pulsed-air mixing equipment has been successfully applied to a number of difficult mixing applications in various chemical-process industries. Most previous applications involved the mixing of particle-free viscous fluids. The study described in this report was preformed to improve the understanding of how pulsed-air mixing applies to slurries. This document describes work conducted to evaluate the potential application of pulsed-air mixers to the slurry- mixing needs of the US Department of Energy's waste-retrieval programs

  13. A new mathematical model of wrist pulse waveforms characterizes patients with cardiovascular disease - A pilot study.

    Science.gov (United States)

    He, Dianning; Wang, Lu; Fan, Xiaobing; Yao, Yang; Geng, Ning; Sun, Yingxian; Xu, Lisheng; Qian, Wei

    2017-10-01

    The purpose of this study was to analyze and compare a series of measured radial pulse waves as a function of contact pressure for young and old healthy volunteers, and old patients with cardiovascular disease. The radial pulse waves were detected with a pressure sensor and the contact pressure of the sensor was incremented by 20gf during the signal acquisition. A mathematical model of radial pulse waveform was developed by using two Gaussian functions modulated by radical functions and used to fit the pulse waveforms. Then, a ratio of area (r A ) and a ratio of peak height (r PH ) between percussion wave and dicrotic wave as a function of contact pressure were calculated based on fitted parameters. The results demonstrated that there was a maximum for waveform peak height, a minimum for r A (r A min ) and a minimum for r PH (r PH min ) appeared as contact pressure varied. On average, older patients had higher peak amplitude and a significantly smaller r A min (pmathematical model had moderate to strong positive linear correlations (r=0.66 to 0.84, pmodel. The receiver operating characteristic (ROC) analysis showed that the r A min calculated with the model and the contact pressure measured at the r A min had good diagnostic accuracy to distinguish healthy volunteers vs. diseased patients. Therefore, using the mathematical model to quantitatively analyze the radial pulse waveforms as a function of contact pressure could be useful in the diagnosis of cardiovascular diseases. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

  14. A magnetic resonance study of 3d transition metals and thermal donors in silicon

    International Nuclear Information System (INIS)

    Wezep, D.A. van.

    1986-01-01

    This thesis describes a study of 3d-transition metal impurities in silicon (titanium and iron in particular) and a study of oxygen-related heat-treatment centers in silicon, both carried out mainly by magnetic resonances techniques like EPR and ENDOR. 119 refs.; 31 figs.; 14 tabs

  15. An optimization study of peak thermal neutron flux in moderators of advanced repetitive pulse reactors

    International Nuclear Information System (INIS)

    Asaoka, Takumi; Watanabe, N.

    1976-01-01

    In achieving a high peak thermal neutron flux in hydrogenous moderators installed in repetitive pulse reactors, the core-moderator arrangement can play as much an important role as the moderator design itself. However, the effect of the former has not been adequately emphasized to date, while a rather extensive study has been made on the latter. The present study concerns with a core-moderator system parameter optimization for a repetitive accelerator pulsed fast reactor. The results have shown that small differences in the arrangement resulting from the optimizations of various parameters are significant and the effects can be summed up to give an increase in the peak thermal flux by a factor of about two. (auth.)

  16. Short-pulse CO2-laser damage studies of NaCl and KCl windows

    International Nuclear Information System (INIS)

    Newnam, B.E.; Nowak, A.V.; Gill, D.H.

    1979-01-01

    The damage resistance of bare surfaces and the bulk interior of NaCl and KCl windows was measured with a short-pulse CO 2 laser at 10.6 μm. Parametric studies with 1.7-ns pulses indicated that adsorbed water was probably the limiting agent on surface thresholds in agreement with previous studies at long pulsewidths. Rear-surface thresholds up to 7 J/cm 2 were measured for polished NaCl windows, whereas KCl surfaces damaged at approximately 60% of this level. The breakdown electric-field thresholds of exit surfaces were only 50% of the value of the bulk materials. The pulsewidth dependence of surface damage from 1 to 65 ns, in terms of incident laser fluence, increased as t/sup 1/3/

  17. Study of heterogeneous multiplying and non-multiplying media by the neutron pulsed source technique

    International Nuclear Information System (INIS)

    Deniz, V.

    1969-01-01

    The pulsed neutron technique consists essentially in sending in the medium to be studied a short neutron pulse and in determining the asymptotic decay constant of the generated population. The variation of the decay constant as a function of the size of the medium allows the medium characteristics to be defined. This technique has been largely developed these last years and has been applied as well to moderator as to multiplying media, in most cases homogeneous ones. We considered of interest of apply this technique to lattices, to see if useful informations could be collected for lattice calculations. We present here a general theoretical study of the problem, and results and interpretation of a series of experiments made on graphite lattices. There is a good agreement for non-multiplying media. In the case of multiplying media, it is shown that the age value used until now in graphite lattices calculations is over-estimated by about 10 per cent [fr

  18. Studying Intense Pulsed Light Method Along With Corticosteroid Injection in Treating Keloid Scars

    OpenAIRE

    Shamsi Meymandi, Simin; Rezazadeh, Azadeh; Ekhlasi, Ali

    2014-01-01

    Background: Results of various studies suggest that the hypertrophic and keloid scars are highly prevalent in the general population and are irritating both physically and mentally. Objective: Considering the variety of existing therapies, intense pulsed light (IPL) method along with corticosteroid injection was evaluated in treating these scars. Materials and Methods: 86 subjects were included in this clinical trial. Eight sessions of therapeutic intervention were done with IPL along with co...

  19. Pulse radiolysis study of the reduction mechanism of an antitumor antibiotic, mitomycin C

    International Nuclear Information System (INIS)

    Machtalere, G.; Houee-Levin, C.; Gardes-Albert, M.; Ferradini, C.; Hickel, B.

    1988-01-01

    Mitomycin C is a quinonic antitumor metabolized in vivo by one-electron reduction. We have studied the mechanism of the one-electron reduction of this drug by pulse radiolysis using C00 .- free radicals as reductants. Semiquinonic and hydroquinonic intermediates are formed. The hydroquinonic form undergoes a methanol elimination leading to a transient which can disappear in one of two ways: by either internal redox reaction or hydrolysis of the aziridine. 17 refs [fr

  20. Technical design study. BESSY VSR. Variable pulse length Storage Ring. Upgrade of BESSY II

    International Nuclear Information System (INIS)

    2015-06-01

    BESSY-VSR is a novel approach to create in the Storage Ring BESSY II long and short photon pulses simultaneously for all beam lines through a pair of superconducting bunch compression cavities. Pulse-picking schemes will allow each individual user to freely switch between high average flux for X-ray spectroscopy, microscopy and scattering and picosecond pulses up to 500 MHz repetition rate for dynamic studies. Thus BESSY-VSR preserves the present average brilliance of BESSY II and adds the new capability of user accessible picosecond pulses at high repetition rate. In addition, high intensities for THz radiation with intrinsic synchronization of THz and X-ray pulses can be extracted from BESSY-VSR. For the scientific challenges of quantum materials for energy, future information technologies and basic energy science BESSY-VSR is the multi-user Synchrotron Radiation facility that allows with the flexible switching between high repetition rate for picosecond dynamics and high average brightness to move classical 3rd generation Synchrotron Radiation science from the observation of static properties and their quantum mechanical description towards the function and the control of materials properties, technologically relevant switching processes and chemical dynamics and kinetics on the picosecond time scale. Strategic relevance of BESSY-VSR for science with photons BESSY-VSR creates for the highly productive Synchrotron Radiation community a uniquely attractive multi user storage ring adding the soft X-ray picosecond dynamics at MHz repetition rate. In particular investigations on reversible dynamics and switching in molecular systems and materials are accessible in a non destructive way. The investigations with X-rays from BESSY-VSR are highly complementary and compatible to dynamic studies conducted by users with optical lasers at their home universities and laboratories. Technologically, the employed superconducting bunch compression cavities in BESSY-VSR are a

  1. Technical design study. BESSY VSR. Variable pulse length Storage Ring. Upgrade of BESSY II

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2015-06-15

    BESSY-VSR is a novel approach to create in the Storage Ring BESSY II long and short photon pulses simultaneously for all beam lines through a pair of superconducting bunch compression cavities. Pulse-picking schemes will allow each individual user to freely switch between high average flux for X-ray spectroscopy, microscopy and scattering and picosecond pulses up to 500 MHz repetition rate for dynamic studies. Thus BESSY-VSR preserves the present average brilliance of BESSY II and adds the new capability of user accessible picosecond pulses at high repetition rate. In addition, high intensities for THz radiation with intrinsic synchronization of THz and X-ray pulses can be extracted from BESSY-VSR. For the scientific challenges of quantum materials for energy, future information technologies and basic energy science BESSY-VSR is the multi-user Synchrotron Radiation facility that allows with the flexible switching between high repetition rate for picosecond dynamics and high average brightness to move classical 3rd generation Synchrotron Radiation science from the observation of static properties and their quantum mechanical description towards the function and the control of materials properties, technologically relevant switching processes and chemical dynamics and kinetics on the picosecond time scale. Strategic relevance of BESSY-VSR for science with photons BESSY-VSR creates for the highly productive Synchrotron Radiation community a uniquely attractive multi user storage ring adding the soft X-ray picosecond dynamics at MHz repetition rate. In particular investigations on reversible dynamics and switching in molecular systems and materials are accessible in a non destructive way. The investigations with X-rays from BESSY-VSR are highly complementary and compatible to dynamic studies conducted by users with optical lasers at their home universities and laboratories. Technologically, the employed superconducting bunch compression cavities in BESSY-VSR are a

  2. Study on Digital Pulse Shape Discrimination System in BF{sub 3} Detector

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jinhyeong; Kim, J. H.; Choi, H. D. [Seoul National Univ., Seoul (Korea, Republic of)

    2013-10-15

    In this study, we develop the digital PSD system and discriminate the background signal of BF{sub 3}. Spectrum shapes are different according to the t{sub start} setting method, and it is favorable to set it as the certain ratio of maximum height. In future, it will be performed to vary t{sub start} point to optimize the pulse discrimination. To quantify the performance, Figure Of Merit (FOM) will be determined. For the nuclear non-proliferation and safeguards, an accurate and reliable measurement of nuclear material is essential. The nuclear material emits neutron and γ-ray, simultaneously. For the accurate detection of the nuclear material, neutron should be discriminated from γ-ray or background radiation. In previous study, N. S. Jung developed pulse shape analysis method based on NIM and CAMAC system. However, applications of other discrimination methods based on different detection modules or changing parameters are time-and-money consuming procedures in analogue systems. Today, the performance of digitizers is improved and it replaces some radiation measurement systems which require simple and portable equipment. Digital Pulse Shape Discrimination (PSD) method by using a digital oscilloscope is developed and applied to a neutron detection system by using BF{sub 3} detector in this study.

  3. Optical design and studies of a tiled single grating pulse compressor for enhanced parametric space and compensation of tiling errors

    Science.gov (United States)

    Daiya, D.; Patidar, R. K.; Sharma, J.; Joshi, A. S.; Naik, P. A.; Gupta, P. D.

    2017-04-01

    A new optical design of tiled single grating pulse compressor has been proposed, set-up and studied. The parametric space, i.e. the laser beam diameters that can be accommodated in the pulse compressor for the given range of compression lengths, has been calculated and shown to have up to two fold enhancement in comparison to our earlier proposed optical designs. The new optical design of the tiled single grating pulse compressor has an additional advantage of self compensation of various tiling errors like longitudinal and lateral piston, tip and groove density mismatch, compared to the earlier designs. Experiments have been carried out for temporal compression of 650 ps positively chirped laser pulses, at central wavelength 1054 nm, down to 235 fs in the tiled grating pulse compressor set up with the proposed design. Further, far field studies have been performed to show the desired compensation of the tiling errors takes place in the new compressor.

  4. Studies of the pulse charge of lead-acid batteries for PV applications. Part I. Factors influencing the mechanism of the pulse charge of the positive plate

    Energy Technology Data Exchange (ETDEWEB)

    Kirchev, A.; Perrin, M.; Lemaire, E.; Karoui, F.; Mattera, F. [Commissariat de l' Energie Atomique, Institut National de l' Energie Solaire, INES-RDI, Parc Technologique de Savoie Technolac, 50 Avenue du Lac Leman, 73377 Le Bourget du Lac Cedex (France)

    2008-02-15

    The mechanism of the positive plate charge in pulse regime was studied in model lead-acid cells with one positive and two negative plates (8 Ah each) and Ag/Ag{sub 2}SO{sub 4} reference electrodes. The results showed that the evolution of the electrode potential is much slower on the positive plate than on the negative plate. Regardless of this fact, the calculated capacitive current of charge and self-discharge of the electrochemical double layer (EDL) during the 'ON' and 'OFF' half-periods of the pulse current square waves is comparable with the charge current amplitude. The result is due to the high values of the EDL on the surface of the lead dioxide active material. The influence of different factors like state of charge, state of health, pulse frequency, current amplitude and open circuit stay before the polarization was discussed. The previously determined optimal frequency of 1 Hz was associated with a maximum in the average double layer current on frequency dependence. The average double layer current is also maximal at SOC between 75 and 100%. The exchange of the constant current polarization with pulse polarization does not change substantially the mechanism and the overvoltage of the oxygen evolution reaction on the positive plate. The mechanism of the self-discharge of the EDL was also estimated analyzing long-time PPP transients (up to 2 h). It was found that when the PPP is lower than 1.2 V the preferred mechanism of EDL self-discharge is by coupling with the lead sulphate oxidation reaction. At higher values of PPP the EDL self-discharge happens via oxygen evolution. The high faradic efficiency of the pulse charge is due to the chemical oxidation of the Pb(II) ions by the O atoms and OH radicals formed at the oxygen evolution both during the 'ON' and 'OFF' periods. (author)

  5. Study on the construction and its operating characteristics of Marx high voltage pulse generator

    International Nuclear Information System (INIS)

    Chung, W.K.; Yook, C.C.

    1984-01-01

    This study is to investigate the operating characteristics of a Marx high voltage pulse generator, which is designed and fabricated for the purpose of constructing a linear theta-pinch plasma generating facility. The Marx generator consists of a 2 kJ capacitor bank of maximum output voltage of 200kV, a set of main spark switch, a triggring system, and high voltage charging power supply. The experimental results show that the operating characteristics of the generator can be controlled through varying nitrogen pressure as a filling gas. The output pulse of the generator is achieved close to the estimated voltage with the rise time of 3*m seconds. The stability of the generator is also very satisfactory within operating range of main spark switch. (Author)

  6. Damage threshold of lithium niobate crystal under single and multiple femtosecond laser pulses: theoretical and experimental study

    International Nuclear Information System (INIS)

    Meng, Qinglong; Zhang, Bin; Zhong, Sencheng; Zhu, Liguo

    2016-01-01

    The damage threshold of lithium niobate crystal under single and multiple femtosecond laser pulses has been studied theoretically and experimentally. Firstly, the model for the damage threshold prediction of crystal materials based on the improved rate equation has been proposed. Then, the experimental measure method of the damage threshold of crystal materials has been given in detail. On the basis, the variation of the damage threshold of lithium niobate crystal with the pulse duration has also been analyzed quantitatively. Finally, the damage threshold of lithium niobate crystal under multiple laser pulses has been measured and compared to the theoretical results. The results show that the transmittance of lithium niobate crystal is almost a constant when the laser pulse fluence is relative low, whereas it decreases linearly with the increase in the laser pulse fluence below the damage threshold. The damage threshold of lithium niobate crystal increases with the increase in the duration of the femtosecond laser pulse. And the damage threshold of lithium niobate crystal under multiple laser pulses is obviously lower than that irradiated by a single laser pulse. The theoretical data fall in good agreement with the experimental results. (orig.)

  7. Square biphasic pulse deep brain stimulation for essential tremor: The BiP tremor study.

    Science.gov (United States)

    De Jesus, Sol; Almeida, Leonardo; Shahgholi, Leili; Martinez-Ramirez, Daniel; Roper, Jaimie; Hass, Chris J; Akbar, Umer; Wagle Shukla, Aparna; Raike, Robert S; Okun, Michael S

    2018-01-01

    Conventional deep brain stimulation (DBS) utilizes regular, high frequency pulses to treat medication-refractory symptoms in essential tremor (ET). Modifications of DBS pulse shape to achieve improved effectiveness is a promising approach. The current study assessed the safety, tolerability and effectiveness of square biphasic pulse shaping as an alternative to conventional ET DBS. This pilot study compared biphasic pulses (BiP) versus conventional DBS pulses (ClinDBS). Eleven ET subjects with clinically optimized ventralis intermedius nucleus DBS were enrolled. Objective measures were obtained over 3 h while ON BiP stimulation. There was observed benefit in the Fahn-Tolosa Tremor Rating Scale (TRS) for BiP conditions when compared to the DBS off condition and to ClinDBS setting. Total TRS scores during the DBS OFF condition (28.5 IQR = 24.5-35.25) were significantly higher than the other time points. Following active DBS, TRS improved to (20 IQR = 13.8-24.3) at ClinDBS setting and to (16.5 IQR = 12-20.75) at the 3 h period ON BiP stimulation (p = 0.001). Accelerometer recordings revealed improvement in tremor at rest (χ 2  = 16.1, p = 0.006), posture (χ 2  = 15.9, p = 0.007) and with action (χ 2  = 32.1, p=<0.001) when comparing median total scores at ClinDBS and OFF DBS conditions to 3 h ON BiP stimulation. There were no adverse effects and gait was not impacted. BiP was safe, tolerable and effective on the tremor symptoms when tested up to 3 h. This study demonstrated the feasibility of applying a novel DBS waveform in the clinic setting. Larger prospective studies with longer clinical follow-up will be required. Copyright © 2017. Published by Elsevier Ltd.

  8. Preliminary studies of the quickly pulsed synchrotron involved in the Beta-Beam project; Etudes preliminaires du synchrotron rapidement pulse du projet Beta-Beam

    Energy Technology Data Exchange (ETDEWEB)

    Lachaize, A

    2007-07-01

    This study presents a quickly-pulsed synchrotron able to accelerate He{sup 6} and Ne{sup 18} beams from 100 MeV/u till 3.5 GeV (proton equivalent) The accelerator is made up of 48 bending dipoles and 42 focusing quadrupoles. The design of the HF accelerating system, the bunch injection and the correction of errors in beam dynamics are dealt with.

  9. Study of performance of electronic dosemeters in continuous and pulsed X-radiation beams

    International Nuclear Information System (INIS)

    Guimaraes, Margarete Cristina

    2014-01-01

    Personal radiation monitoring is a basic procedure to verify the compliance to regulatory requirements for radiological protection. Electronic personal dosimeters (EPD) based on solid state detectors have largely been used for personnel monitoring; including for pulsed radiation beams where their responses are not well known and deficiencies have been reported. In this work, irradiation conditions for testing the response of EPDs in both continuous and pulsed X-ray beams were studied to be established in a constant potential Seifert-Pantak and in a medical Pulsar 800 Plus VMI X-ray machines. Characterization of X-ray beams was done in terms of tube voltage, half-value layer, mean energy and air kerma rate. A Xi R/F Unfors solid state dosimeter used as reference for air kerma measurements was verified against a RC-6 and 10X6-6 Radical ionization chambers as far its metrological coherence. Rad-60 RADOS, PDM- 11 Aloka and EPD MK2 Thermo electron EPDs were selected to be tested in terms of relative intrinsic error and energy response in similar to IEC RQR, IEC RQA and ISO N reference radiations. Results demonstrated the reliability of the solid state Xi R/F Unfors dosimeter to be as reference dosimeter although its response was affected by heavily filtered beams. Results also showed that relative intrinsic errors in the response of the EPDs in terms of personal dose equivalent, Hp(10), were higher than the requirement established for continuous beams. In pulsed beams, some EPDs showed inadequate response and high relative intrinsic errors. This work stressed the need of performing additional checks for EPDs, besides the limited 137 Cs beam calibration, before using them in pulsed X-ray beams. (author)

  10. Experimental study on the vascular thermal response to visible laser pulses.

    Science.gov (United States)

    Li, D; Chen, B; Wu, W J; Wang, G X; He, Y L; Ying, Z X

    2015-01-01

    Port-wine stains (PWSs) are congenital vascular malformations that progressively darken and thicken with age, and laser therapy is the most effective in clinical practice. Using dorsal skin chamber (DSC), this study evaluated thermal response of blood vessel to a 595-nm pulsed dye laser (PDL) with controlled energy doses and pulse durations. Totally, 32 vessels (30∼300 μm in diameter) are selected from the dorsal skin of the mouse to match those in port-wine stain. The experimental results showed that the thermal response of the blood vessels to laser irradiation can be recognized as coagulation, constriction with diameter decrease, disappearance (complete constriction), hemorrhage, and collagen damage in the order of increasing laser radiant exposure. Blood vessels with small diameter would response poorly and survive from the laser heating because their thermal relaxation time is much shorter than the pulse duration. The optimalradiant exposure is from 10 to 12 J/cm(2) under 6 ms pulse duration without considering the epidermal light absorption. Numerical simulations were also conducted using a 1,000-μm deep Sprague-Dawley (SD) mouse skinfold. The light transportation and heat diffusion in dorsal skin were simulated with the Monte Carlo method and heat transfer equation, while the blood vessel photocoagulation was evaluated by Arrhenius-type kinetic integral. Both experimental observation and numerical simulation supported that hemorrhage is the dominant thermal response, which occurs due to preferential heating of the superior parts of large blood vessels. In clinical practice for 595 nm PDL, the consequent purpura caused by hemorrhage can be used as a treatment end point.

  11. Design and development of micro pulse lidar for cloud and aerosol studies

    Science.gov (United States)

    Dubey, P. K.; Arya, B. C.; Ahammed, Y. Nazeer; Kumar, Arun; Kulkarni, P. S.; Jain, S. L.

    2008-12-01

    A micro pulse lidar (MPL) has been indigenously designed and developed at the National Physical Laboratory, New Delhi using a 532 nm, 500 pico second pulsed laser having average power of 50mW (at 7.5 KHz PRR). Photon counting technique has been incorporated using the conventional optics, multichannel scaler (Stanford Research Systems SR430) and high sensitive photomultiplier tube. The sensitivity, range and bin etc are computer controlled in the present system. The interfacing between MPL and computer has been achieved by serial (RS232) and parallel printer port. The necessary software and graphical user interface has been developed using visual basic. In addition to this the telescope cover status sensing circuit has been incorporated to avoid conflict between dark count and background acquisition. The micro pulse lidar will be used for the aerosol, boundary layer and the cloud studies at a bin resolution of 6 meters. In the present communication the details of the system and preliminary results will be presented.

  12. Use of a ring chromosome and pulsed-field gels to study recombinational repair

    International Nuclear Information System (INIS)

    Game, J.C.; Arabi, S.; Mortimer, R.K.

    1989-01-01

    In wild type yeast, it is known that x-ray induced DNA double-strand breaks (dsb) are repaired, leading to recovery of high molecular-weight molecules on gradients or pulsed-field gels. There is genetic evidence that some or all of this repair occurs via recombinational mechanisms involving sister-chromatid exchange (SCE) and (in diploids) inter-homologue recombination. However, this evidence is indirect and qualitative. The authors of this paper are attempting to use pulsed-field gels to detect and measure recombinational repair at the physical level in yeast strains with a circular homologue of Chr. III. The authors have previously used such strains to study meiotic recombination. The authors have shown that double-size circular molecules can be detected in log-phase haploid yeast cells carrying a ring chromosome, when such cells are exposed to x-rays and allowed time for subsequent repair. Large circular molecules will not enter our pulsed-field gels, but treatment of the DNA samples with radiation prior to running the gels will linearize a fraction of such molecules with a single dsb. Such linearized molecules will run as a band whose position indicates the size of the original unbroken circles

  13. Studies on the wetting properties of plate surfaces used in pulsed extraction columns

    International Nuclear Information System (INIS)

    Tai Derong; Yang Xin; Wang Xinchang

    1991-01-01

    Many factors influence the hydrodynamic characteristics of pulsed column. Of all the factors the surface effect at liquid-liquid interfaces and liquid-solid boundaries may be the most influential factor to the state of droplets. In order to get some understanding of the behaviour of droplets in a pulsed column, the time history of wetting properties of plates under different conditions in 30% TBP (Kerosene) -HNO 3 -UO 2 (NO 3 ) 2 -H 2 O systems was studied. The results show that the hydrophilic wetting behaviour of the plates changes into the hydrophobic and neutral conditions, respectively after they have been exposed to air and put in the 'open system' within about 50 days after contacting with process solutions. For the case where the access of air is prohibited at the upper organic phase boundary by a well fitting cover, or supersonic pulse cleaning is used to the cartridge, the behaviour of the metal surface stays in the original good hydrophilic wetting condition constant with time. The uranium charged liquid systems can conserve hydrophilic behaviour better than the non-charged systems under identical conditions. It is also found that the interfacial tension is unvaried with time for saturated process systems, hence it has no effects on the variation of wettability

  14. Studies of Effect Analysis of Electromagnetic Pulses (EMP) in Operating Nuclear Power Plants (NPP)

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Song Hae; Ryu, Ho Sun; Kim, Min Yi; Lee, Eui Jong [KHNP, Daejeon (Korea, Republic of)

    2016-05-15

    The effect analysis of electromagnetic pulses (EMPs) has been studied for the past year by the Central Research Institute of Korea Hydro Nuclear Power Co. (KHNP) in order to better establish safety measures in operating nuclear power plants. What is an electromagnetic pulse (EMP)? As a general term for high-power electromagnetic radiation, it refers to strong electromagnetic pulses that destroy only electronic equipment devices in a short period without loss of life. The effect analysis of EMPs in operating NPPs and their corresponding safety measures in terms of selecting target devices against EMP impact have been examined in this paper. In general, domestic nuclear power plants do apply the design of fail-safe concepts. For example, if key instruments of a system fail because of EMPs, the control rods of a nuclear reactor are dropped automatically in order to maintain safe conditions of the NPP. Reactor cooling presents no problem because the diesel generator will adopt the analog starting circuit least affected by the electromagnetic waves.

  15. Properties of the radicals formed by one-electron oxidation of acetaminophen - a pulse radiolysis study

    International Nuclear Information System (INIS)

    Bisby, R.H.; Tabassum, N.

    1988-01-01

    The semi-iminoquinone radical of acetaminophen, which has previously been proposed as a possible hepatotoxic intermediate in the cytochrome P-450 catalysed oxidation of acetaminophen, has been generated and studied by pulse radiolysis. In the absence of other reactive solutes, the radical decays rapidly by second order kinetics with a rate constant (2k 2 ) of (2.2 ± 0.4) x 10 9 M -1 sec -1 . In alkaline solutions the radical deprotonates with a pK of 11.1 ± 0.1 to form a radical-anion. The acetaminophen radical-anion reacts with resorcinol at high pH values, leading to the formation of a transient equilibrium from which the one-electron reduction potential of the semi-iminoquinone radical of acetaminophen is estimated to be + 0.707 ± 0.01 V at pH 7. This value predicts that acetaminophen should be oxidised by thiyl radicals. This was confirmed by pulse radiolysis experiments for reaction of the cysteinyl radical, for which rate constants of 7 x 10 6 M -1 sec -1 at pH7 and 2.7 x 10 8 M -1 sec -1 at pH 11.3 were obtained. The reaction of O 2 with the acetaminophen semi-iminoquinone radical could not be detected by pulse radiolysis, and alternative mechanisms for superoxide radical formation are discussed. (author)

  16. UV laser interaction with a fluorescent dye solution studied using pulsed digital holography.

    Science.gov (United States)

    Amer, Eynas; Gren, Per; Sjödahl, Mikael

    2013-10-21

    A frequency tripled Q-switched Nd-YAG laser (wavelength 355 nm, pulse duration 12 ns) has been used to pump Coumarin 153 dye solved in ethanol. Simultaneously, a frequency doubled pulse (532 nm) from the same laser is used to probe the solvent perpendicularly resulting in a gain through stimulated laser induced fluorescence (LIF) emission. The resulting gain of the probe beam is recorded using digital holography by blending it with a reference beam on the detector. Two digital holograms without and with the pump beam were recorded. Intensity maps were calculated from the recorded digital holograms and used to calculate the gain of the probe beam due to the stimulated LIF. In addition numerical data of the local temperature rise was calculated from the corresponding phase maps using Radon inversion. It was concluded that about 15% of the pump beam energy is transferred to the dye solution as heat while the rest is consumed in the radiative process. The results show that pulsed digital holography is a promising technique for quantitative study of fluorescent species.

  17. Numerical study on increasing mass flow ratio by energy deposition of high frequency pulsed laser

    International Nuclear Information System (INIS)

    Wang Diankai; Hong Yanji; Li Qian

    2013-01-01

    The mass flow ratio (MFR) of air breathing ramjet inlet would be decreased, when the Mach number is lower than the designed value. High frequency pulsed laser energy was deposited upstream of the cowl lip to reflect the stream so as to increase the MFR. When the Mach number of the flow was 5.0, and the static pressure and temperature of the flow were 2 551.6 Pa and 116.7 K, respectively, two-dimensional non-stationary compressible RANS equations were solved with upwind format to study the mechanisms of increasing MFR by high frequency pulsed laser energy deposition. The laser deposition frequency was 100 kHz and the average power was 500 W. The crossing point of the first forebody oblique shock and extension line of cowl lip was selected as the expected point. Then the deposition position was optimized by searching near the expected point. The results indicate that with the optimization of laser energy deposition position, the MFR would be increased from 63% to 97%. The potential value of increasing MFR by high frequency pulsed laser energy deposition was proved. The method for selection of the energy deposition position was also presented. (authors)

  18. Study on Analysis and Pattern Recognition of the Manifestation of the Pulse Detection of Cerebrovascular Disease

    Energy Technology Data Exchange (ETDEWEB)

    Jing, J; Wang, Y C; Hong, W X; Zhang, W P [Department of Biomedical Engineering, University of Yanshan, Qinhuangdao, Hebei Province, 066004 (China)

    2006-10-15

    Cerebrovascular Disease (CVD) is also called stroke in Traditional Chinese Medicine (TCM). CVD is a kind of frequent diseases with high incidence, high death rate, high deformity rate and high relapse rate. The pathogenesis of CVD has relation to many factors. In modern medicine, we can make use of various instruments to check many biochemical parameters. However, at present, the early detection of CVD can mostly be done artificially by specialists. In TCM the salted expert can detect the state of a CVD patient by felling his (or her) pulse. It is significant to apply the modern information and engineering techniques to the early discovery of CVD. It is also a challenge to do this in fact. In this paper, the authors presented a detection method of CVD basing on analysis and pattern recognition of Manifestation of the Pulse of TCM using wavelet technology and Neural Networks. Pulse signals from normal health persons and CVD patients were studied comparatively. This research method is flexible to deal with other physiological signals.

  19. STUDY OF THE PROPAGATION OF SHORT PULSE LASER WITH CAVITY USING NUMERICAL SIMULATION SOFTWARE

    Directory of Open Access Journals (Sweden)

    S. Terniche

    2015-07-01

    Full Text Available The purpose of this representation is to show the potentialities (Computational Time, access to the dynamic and feasibility of systematic studies of the numerical study of the nonlinear dynamics in laser cavity, assisted by software. We will give as an example, one type of cavity completely fibered composed of several elements and then studying the physical parameters of a pulse propagating into this cavity, determining its characteristics at the output. The results are interesting but we also projects to verify them experimentally by making assemblies similar to this type of cavities.

  20. Study of the oncogenic expression in human fibroblast cells after exposure to very short pulsed laser radiations

    International Nuclear Information System (INIS)

    Dormont, D.; Freville, Th.; Raoul, H.; Courant, D.; Court, L.

    1992-01-01

    The aim of this study is to evaluate the capacity of a laser, delivering very short pulses in the near infrared spectrum with a high pulse ratio frequency, to induce genetic modification on biological tissues. The absence of dicentric among chromosomal aberrations on human lymphocytes suggests that a repetitive very short pulses irradiation has a relatively low capacity to induce genetic abnormalities. The studies of the radiation effects on the cellular growth and the oncogenic expression show that the modifications, induced at the cellular level, do not seem the origin of a cellular transformation and a possible mechanism of carcinogenesis. (author)

  1. Magnetic study of a few antiferromagnets in very-strong pulsed fields (450 kOE)

    International Nuclear Information System (INIS)

    Krebs, J.

    1968-01-01

    In this thesis we describe a pulsed field device with which we obtain magnetization curves up to 450 kOE at all temperatures between 1. 6 and 300. We have studied the 'spin-flopping'(and therefore the anisotropy) in MnF 2 versus temperature, below the Neel point. We have also studied the antiferromagnets MnSO 4 . and MnSO 4 .H 2 O which have revealed saturation fields respectively of 250 kOE and 320 kOE. (author) [fr

  2. Polarized Raman study on the lattice structure of BiFeO3 films prepared by pulsed laser deposition

    KAUST Repository

    Yang, Yang; Yao, Yingbang; Zhang, Q.; Zhang, Xixiang

    2014-01-01

    Polarized Raman spectroscopy was used to study the lattice structure of BiFeO3 films on different substrates prepared by pulsed laser deposition. Interestingly, the Raman spectra of BiFeO3 films exhibit distinct polarization dependences

  3. Optimum pulse duration and radiant exposure for vascular laser therapy of dark port-wine skin: a theoretical study

    International Nuclear Information System (INIS)

    Tunnell, James W.; Anvari, Bahman; Wang, Lihong V.

    2003-01-01

    Laser therapy for cutaneous hypervascular malformations such as port-wine stain birthmarks is currently not feasible for dark-skinned individuals. We study the effects of pulse duration, radiant exposure, and cryogen spray cooling (CSC) on the thermal response of skin, using a Monte Carlo based optical-thermal model. Thermal injury to the epidermis decreases with increasing pulse duration during irradiation at a constant radiant exposure; however, maintaining vascular injury requires that the radiant exposure also increase. At short pulse durations, only a minimal increase in radiant exposure is necessary for a therapeutic effect to be achieved because thermal diffusion from the vessels is minimal. However, at longer pulse durations the radiant exposure must be greatly increased. There exists an optimum pulse duration at which minimal damage to the epidermis and significant injury within the targeted vasculature occur. For example, the model predicts optimum pulse durations of approximately 1.5, 6, and 20 ms for vessel diameters of 40, 80, and 120 μm, respectively. Optimization of laser pulse duration and radiant exposure in combination with CSC may offer a means to treat cutaneous lesions in dark-skinned individuals

  4. Feasibility study for a multi-channel pulsed radar reflectometer for the jet divertor region

    International Nuclear Information System (INIS)

    Heijnen, S.H.; Pol, M.J. van de.

    1994-09-01

    In this report, the feasibility of a pulsed radar system for measuring the electron density profile in the divertor region of JET is studied. Some dedicated experiments are performed with a four-channel system, which was designed for the Rijnhuizen Tokamak Project. To simulate divertor plasmas the measurements are performed in ECRH induced plasmas without current. The parameters of these kinds of plasmas are: n e 19 m -3 , T e <100 eV, and a diameter of ∼30 cm. (HSI)

  5. Study on boron-film thermal neutron converter prepared by pulsed laser deposition

    International Nuclear Information System (INIS)

    Song Zifeng; Ye Shuzhen; Chen Ziyu; Song Liao; Shen Ji

    2011-01-01

    The boron film converter used in the position-sensitive thermal neutron detector is discussed and the method of preparing this converter layer via Pulsed Laser Deposition (PLD) is introduced. The morphology and the composition were studied by Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS). Both boron and boride existed on the layer surface. It was shown that the energy intensity of laser beam and the substrate temperature both had an important influence on the surface morphology of the film.

  6. Study on boron-film thermal neutron converter prepared by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Song Zifeng; Ye Shuzhen; Chen Ziyu; Song Liao [Department of Modern Physics, University of Science and Technology of China, Anhui Hefei 230026 (China); Shen Ji, E-mail: shenji@ustc.edu.c [Department of Modern Physics, University of Science and Technology of China, Anhui Hefei 230026 (China)

    2011-02-15

    The boron film converter used in the position-sensitive thermal neutron detector is discussed and the method of preparing this converter layer via Pulsed Laser Deposition (PLD) is introduced. The morphology and the composition were studied by Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS). Both boron and boride existed on the layer surface. It was shown that the energy intensity of laser beam and the substrate temperature both had an important influence on the surface morphology of the film.

  7. Pulsed EPR studies of Phosphorus shallow donors in diamond and SiC

    International Nuclear Information System (INIS)

    Isoya, J.; Katagiri, M.; Umeda, T.; Koizumi, S.; Kanda, H.; Son, N.T.; Henry, A.; Gali, A.; Janzen, E.

    2006-01-01

    Phosphorus shallow donors having the symmetry lower than T d are studied by pulsed EPR. In diamond:P and 3C-SiC:P, the symmetry is lowered to D 2d and the density of the donor wave function on the phosphorus atom exhibits a predominant p-character. In 4H-SiC:P with the site symmetry of C 3v , the A 1 ground state of the phosphorus donors substituting at the quasi-cubic site of silicon shows an axial character of the distribution of the donor wave function in the vicinity of the phosphorus atom

  8. Tunable pores in mesoporous silica films studied using a pulsed slow positron beam

    International Nuclear Information System (INIS)

    He Chunqing; Muramatsu, Makoto; Ohdaira, Toshiyuki; Oshima, Nagayasu; Kinomura, Atsushi; Suzuki, Ryoichi; Kobayashi, Yoshinori

    2007-01-01

    Positron annihilation lifetime spectroscopy (PALS) based on a pulsed slow positron beam was applied to study mesoporous silica films, synthesized using amphiphilic PEO-PPO-PEO triblock copolymers as structure-directing agents. The pore size depends on the loading of different templates. Larger pores were formed in silica films templated by copolymers with higher molecular-weights. Using 2-dimensional PALS, open porosity of silica films was also found to be influenced by the molecular-weight as well as the ratio of hydrophobic PPO moiety of the templates

  9. Broad line and pulsed NMR study of molecular motion in furfuryl alcohol resins

    International Nuclear Information System (INIS)

    Glowinkowski, S.; Pajak, Z.

    1978-01-01

    Broad line and pulsed nuclear magnetic resonance studies are carried out on a number of furfuryl alcohol resins differentiated by viscosity. Proton NMR spectra and relaxation times T 1 and Tsub(1rho) are measured over a wide temperature range and the results are interpreted in terms of molecular motion. The marked decrease in second moment and existence of high temperature spin-lattice relaxation times minima are presumed to result from rotational motion of polymer chains. The relaxation processes at low temperature are believed to be due to rotational motion of methyl endgroup and paramagnetic centres. (author)

  10. Iron hexacyanide/cytochrome-C - intramolecular electron transfer and binding constants - (pulse radiolytic study). Progress report

    International Nuclear Information System (INIS)

    Ilan, Y.; Shafferman, A.

    Internal oxidation and reduction rates of horse cytochrome-c in the complexes, CII.Fe/sup III/(CN) -3 6 and CIII.Fe/sup II/(CN) -4 6 , are 4.6.10 4 s -1 and 3.3.10 2 s -1 , respectively. The binding sites of the iron hexacyanide ions on either CII or CIII are kinetically almost indistinguishable; binding constants range from 0.87.10 3 to 2.10 3 M -1 . The present pulse radiolytic kinetic data are compared with that from N.M.R, T-jump and equilibrium dialysis studies

  11. Positron and positronium annihilation in silica-based thin films studied by a pulsed positron beam

    International Nuclear Information System (INIS)

    Suzuki, R.; Ohdaira, T.; Kobayashi, Y.; Ito, K.; Shioya, Y.; Ishimaru, T.

    2003-01-01

    Positron and positronium annihilation in silica-based thin films has been investigated by means of measurement techniques with a monoenergetic pulsed positron beam. The age-momentum correlation study revealed that positron annihilation in thermally grown SiO 2 is basically the same as that in bulk amorphous SiO 2 while o-Ps in the PECVD grown SiCOH film predominantly annihilate with electrons of C and H at the microvoid surfaces. We also discuss time-dependent three-gamma annihilation in porous low-k films by two-dimensional positron annihilation lifetime spectroscopy

  12. Photochemistry of CS2/Cl complexes-combined pulse radiolysis-laser flash photolysis studies

    International Nuclear Information System (INIS)

    Sumiyoshi, Takashi; Nakayama, Masayoshi; Fujiyoshi, Ryoko; Sawamura, Sadashi

    2006-01-01

    Complexes of chlorine atoms and carbon disulfide (CS 2 ) were produced by pulse radiolysis of CS 2 in halocarbons and photochemical reactions were studied by laser flash photolysis. Excitation of CS 2 /Cl complexes resulted in rapid and permanent photobleaching. The photobleaching of CS 2 /Cl complexes is due to intermolecular chlorine atom abstraction in CCl 4 with a quantum yield of 0.04, while that ascribed to hydrogen atom abstraction in 1,2-dichloroethane has a quantum yield of 0.21. The effects of additives are discussed based on the bond dissociation energy

  13. A Three-Pulse Release Tablet for Amoxicillin: Preparation, Pharmacokinetic Study and Physiologically Based Pharmacokinetic Modeling.

    Science.gov (United States)

    Li, Jin; Chai, Hongyu; Li, Yang; Chai, Xuyu; Zhao, Yan; Zhao, Yunfan; Tao, Tao; Xiang, Xiaoqiang

    2016-01-01

    Amoxicillin is a commonly used antibiotic which has a short half-life in human. The frequent administration of amoxicillin is often required to keep the plasma drug level in an effective range. The short dosing interval of amoxicillin could also cause some side effects and drug resistance, and impair its therapeutic efficacy and patients' compliance. Therefore, a three-pulse release tablet of amoxicillin is desired to generate sustained release in vivo, and thus to avoid the above mentioned disadvantages. The pulsatile release tablet consists of three pulsatile components: one immediate-release granule and two delayed release pellets, all containing amoxicillin. The preparation of a pulsatile release tablet of amoxicillin mainly includes wet granulation craft, extrusion/spheronization craft, pellet coating craft, mixing craft, tablet compression craft and film coating craft. Box-Behnken design, Scanning Electron Microscope and in vitro drug release test were used to help the optimization of formulations. A crossover pharmacokinetic study was performed to compare the pharmacokinetic profile of our in-house pulsatile tablet with that of commercial immediate release tablet. The pharmacokinetic profile of this pulse formulation was simulated by physiologically based pharmacokinetic (PBPK) model with the help of Simcyp®. Single factor experiments identify four important factors of the formulation, namely, coating weight of Eudragit L30 D-55 (X1), coating weight of AQOAT AS-HF (X2), the extrusion screen aperture (X3) and compression forces (X4). The interrelations of the four factors were uncovered by a Box-Behnken design to help to determine the optimal formulation. The immediate-release granule, two delayed release pellets, together with other excipients, namely, Avicel PH 102, colloidal silicon dioxide, polyplasdone and magnesium stearate were mixed, and compressed into tablets, which was subsequently coated with Opadry® film to produce pulsatile tablet of

  14. Positron annihilation in SiO 2-Si studied by a pulsed slow positron beam

    Science.gov (United States)

    Suzuki, R.; Ohdaira, T.; Uedono, A.; Kobayashi, Y.

    2002-06-01

    Positron and positronium (Ps) behavior in SiO 2-Si have been studied by means of positron annihilation lifetime spectroscopy (PALS) and age-momentum correlation (AMOC) spectroscopy with a pulsed slow positron beam. The PALS study of SiO 2-Si samples, which were prepared by a dry-oxygen thermal process, revealed that the positrons implanted in the Si substrate and diffused back to the interface do not contribute to the ortho-Ps long-lived component, and the lifetime spectrum of the interface has at least two components. From the AMOC study, the momentum distribution of the ortho-Ps pick-off annihilation in SiO 2, which shows broader momentum distribution than that of crystalline Si, was found to be almost the same as that of free positron annihilation in SiO 2. A varied interface model was proposed to interpret the results of the metal-oxide-semiconductor (MOS) experiments. The narrow momentum distribution found in the n-type MOS with a negative gate bias voltage could be attributed to Ps formation and rapid spin exchange in the SiO 2-Si interface. We have developed a two-dimensional positron lifetime technique, which measures annihilation time and pulse height of the scintillation gamma-ray detector for each event. Using this technique, the positronium behavior in a porous SiO 2 film, grown by a sputtering method, has been studied.

  15. A time-pulsed positronium beam and a study of oxides on silicon using positrons

    International Nuclear Information System (INIS)

    Khatri, R.K.

    1993-01-01

    The studies on rare gas solid moderators were carried out with a 350 μCi 22 Na radioactive source. The corrected efficiency for neon moderator in conical geometrical configuration was as high as (1.4 ± 0.2)%. The conical configuration moderator performed better by a factor of (2.2 ± 0.2) than the cylindrical configuration. A time pulsed positron beam was built to carry out investigations on the positronium formation processes and positronium beam. This beam has the capability to store low energy e + in a magnetic bottle, with a magnetic bottle at one end and an electrostatic mirror at the other. These stored e + are then bunched to form a pulse with a buncher. The bunched beam had a FWHM of 17 nsec and contained 1 to 2 e + /pulse. A thin carbon foil of 50 angstrom thickness was used for positronium formation by process of charge exchange. Positronium Annihilation Spectroscopy (PAS) was utilized to carry out studies on the activation energy of hydrogen at the interface of oxide and silicon substrate and the effect of irradiation on the oxides in SiO 2 /Si(100) sample. The activation energy of hydrogen at the interface of SiO 2 /Si(100) samples with n- and p-type substrate was measured to be 2.60(6) eV and 2.47(6) eV respectively. The investigations of the samples irradiated with x-ray and γ-ray led to the first time identification of creation of E' centers with PAS

  16. Studying intense pulsed light method along with corticosteroid injection in treating keloid scars.

    Science.gov (United States)

    Shamsi Meymandi, Simin; Rezazadeh, Azadeh; Ekhlasi, Ali

    2014-02-01

    Results of various studies suggest that the hypertrophic and keloid scars are highly prevalent in the general population and are irritating both physically and mentally. Considering the variety of existing therapies, intense pulsed light (IPL) method along with corticosteroid injection was evaluated in treating these scars. 86 subjects were included in this clinical trial. Eight sessions of therapeutic intervention were done with IPL along with corticosteroid intralesional injection using 450 to 1200 NM filter, Fluence 30-40 J/cm2, pulse duration of 2.1-10 ms and palsed delay 10-40 ms with an interval of three weeks. To specify the recovery consequences and complication rate and to determine features of the lesion, the criteria specified in the study of Eroll and Vancouver scar scale were used. The level of clinical improvement, color improvement and scar height was 89.1%, 88.8% and 89.1% respectively. The incidence of complications (1 telangiectasia case, 7 hyperpigmentation cases and 2 atrophy cases) following treatment with IPL was 11.6%. Moreover, the participants' satisfaction with IPL method was 88.8%. This study revealed that a combined therapy (intralesional corticosteroid injection + IPL) increases the recovery level of hypertrophic and keloid scars. It was also demonstrated that this method had no significant side effect and patients were highly satisfied with this method.

  17. Portable pulse X-ray micro and nanosecond range apparatus for studying fast-going processes in opaque media

    International Nuclear Information System (INIS)

    Goganov, D.A.; Komyak, N.I.; Pelix, E.A.

    Pulse X-radiography (X-ray flash duration in the order of 10 -6 -10 -9 sec) is the principal method for studying fast-going processes in opaque media by serial and parallel radiographic imaging. Description is given and main features are outlined of pulse X-ray apparatus IRA-4b, 5b, 6b producing X-radiation flashes from 0.3 μsec to 10-20 nsec in duration

  18. An analyzer for pulse-interval times to study high-order effects in the processing of nuclear detector signals

    International Nuclear Information System (INIS)

    Denecke, B.; Jonge, S. de

    1998-01-01

    An electronic device to measure interval time density distributions of subsequent pulses in nuclear detectors and their electronics is described. The device has a pair-pulse resolution of 10 ns and 25 ns for 3 subsequent input signals. The conversion range is 4096 channels and the lowest channel width is 10 ns. Counter dead times, single and in series were studied and compared with the statistical model. True count rates were obtained from an exponential fit through the interval-time distribution

  19. Studies on the hydrodynamic properties of the sieve plate pulsed column for 30% TRPO-kerosene/nitric acid system

    International Nuclear Information System (INIS)

    Ma Ronglin; Chen Jing; Xu Shiping; Wu Qiulin; Tai Derong; Song Chongli

    2000-01-01

    The hydrodynamic properties of the sieve plate pulsed column for 30% TRPO-kerosene/nitric acid system is studied. With the organic phase or aqueous phase as the continuous one, the dispersed phase behaves mainly as coalescing or dispersing, respectively. The sieve plate pulsed column has a fairish flooding throughput for this system. Under the same pulsation intensity, the flooding throughput for the organic phase as the continuous one is more than that for the aqueous phase as the continuous one

  20. Ultra-short laser pulse ablation using shear-force feedback: Femtosecond laser induced breakdown spectroscopy feasibility study

    International Nuclear Information System (INIS)

    Samek, Ota; Kurowski, Andre; Kittel, Silke; Kukhlevsky, Sergei; Hergenroeder, Roland

    2005-01-01

    This work reports on a feasibility study of proximity ablation using femtosecond pulses. Ultra-short pulses were launched to a bare tapered optical fiber and delivered to the sample. The tip-sample distance was controlled by means of shear-force feedback. Consequently, ablation craters with submicrometer dimensions were obtained. Potential analytical applications for Laser Induced Breakdown Spectroscopy (LIBS) technique, such as e.g. inclusions in steel or bio cells, are suggested

  1. Scoping Study of Airlift Circulation Technologies for Supplemental Mixing in Pulse Jet Mixed Vessels

    Energy Technology Data Exchange (ETDEWEB)

    Schonewill, Philip P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Berglin, Eric J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Boeringa, Gregory K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Buchmiller, William C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Burns, Carolyn A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Minette, Michael J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-04-07

    At the request of the U.S. Department of Energy Office of River Protection, Pacific Northwest National Laboratory (PNNL) conducted a scoping study to investigate supplemental technologies for supplying vertical fluid motion and enhanced mixing in Waste Treatment and Immobilization Plant (WTP) vessels designed for high solids processing. The study assumed that the pulse jet mixers adequately mix and shear the bottom portion of a vessel. Given that, the primary function of a supplemental technology should be to provide mixing and shearing in the upper region of a vessel. The objective of the study was to recommend a mixing technology and configuration that could be implemented in the 8-ft test vessel located at Mid-Columbia Engineering (MCE). Several mixing technologies, primarily airlift circulator (ALC) systems, were evaluated in the study. This technical report contains a review of ALC technologies, a description of the PNNL testing and accompanying results, and recommended features of an ALC system for further study.

  2. Failure rate modeling using fault tree analysis and Bayesian network: DEMO pulsed operation turbine study case

    Energy Technology Data Exchange (ETDEWEB)

    Dongiovanni, Danilo Nicola, E-mail: danilo.dongiovanni@enea.it [ENEA, Nuclear Fusion and Safety Technologies Department, via Enrico Fermi 45, Frascati 00040 (Italy); Iesmantas, Tomas [LEI, Breslaujos str. 3 Kaunas (Lithuania)

    2016-11-01

    Highlights: • RAMI (Reliability, Availability, Maintainability and Inspectability) assessment of secondary heat transfer loop for a DEMO nuclear fusion plant. • Definition of a fault tree for a nuclear steam turbine operated in pulsed mode. • Turbine failure rate models update by mean of a Bayesian network reflecting the fault tree analysis in the considered scenario. • Sensitivity analysis on system availability performance. - Abstract: Availability will play an important role in the Demonstration Power Plant (DEMO) success from an economic and safety perspective. Availability performance is commonly assessed by Reliability Availability Maintainability Inspectability (RAMI) analysis, strongly relying on the accurate definition of system components failure modes (FM) and failure rates (FR). Little component experience is available in fusion application, therefore requiring the adaptation of literature FR to fusion plant operating conditions, which may differ in several aspects. As a possible solution to this problem, a new methodology to extrapolate/estimate components failure rate under different operating conditions is presented. The DEMO Balance of Plant nuclear steam turbine component operated in pulse mode is considered as study case. The methodology moves from the definition of a fault tree taking into account failure modes possibly enhanced by pulsed operation. The fault tree is then translated into a Bayesian network. A statistical model for the turbine system failure rate in terms of subcomponents’ FR is hence obtained, allowing for sensitivity analyses on the structured mixture of literature and unknown FR data for which plausible value intervals are investigated to assess their impact on the whole turbine system FR. Finally, the impact of resulting turbine system FR on plant availability is assessed exploiting a Reliability Block Diagram (RBD) model for a typical secondary cooling system implementing a Rankine cycle. Mean inherent availability

  3. Failure rate modeling using fault tree analysis and Bayesian network: DEMO pulsed operation turbine study case

    International Nuclear Information System (INIS)

    Dongiovanni, Danilo Nicola; Iesmantas, Tomas

    2016-01-01

    Highlights: • RAMI (Reliability, Availability, Maintainability and Inspectability) assessment of secondary heat transfer loop for a DEMO nuclear fusion plant. • Definition of a fault tree for a nuclear steam turbine operated in pulsed mode. • Turbine failure rate models update by mean of a Bayesian network reflecting the fault tree analysis in the considered scenario. • Sensitivity analysis on system availability performance. - Abstract: Availability will play an important role in the Demonstration Power Plant (DEMO) success from an economic and safety perspective. Availability performance is commonly assessed by Reliability Availability Maintainability Inspectability (RAMI) analysis, strongly relying on the accurate definition of system components failure modes (FM) and failure rates (FR). Little component experience is available in fusion application, therefore requiring the adaptation of literature FR to fusion plant operating conditions, which may differ in several aspects. As a possible solution to this problem, a new methodology to extrapolate/estimate components failure rate under different operating conditions is presented. The DEMO Balance of Plant nuclear steam turbine component operated in pulse mode is considered as study case. The methodology moves from the definition of a fault tree taking into account failure modes possibly enhanced by pulsed operation. The fault tree is then translated into a Bayesian network. A statistical model for the turbine system failure rate in terms of subcomponents’ FR is hence obtained, allowing for sensitivity analyses on the structured mixture of literature and unknown FR data for which plausible value intervals are investigated to assess their impact on the whole turbine system FR. Finally, the impact of resulting turbine system FR on plant availability is assessed exploiting a Reliability Block Diagram (RBD) model for a typical secondary cooling system implementing a Rankine cycle. Mean inherent availability

  4. Study of phonon-induced energy transfer processes in crystals using heat pulses

    International Nuclear Information System (INIS)

    Burns, A.R.

    1978-03-01

    The artificial generation of acoustic lattice vibrations by a heat pulse technique is developed in order to probe phonon interactions in molecular crystals. Specifically, the phonon-assisted delocalization of ''trapped'' excited triplet state energy in the aromatic crystal 1,2,4,5-tetrachlorobenzene (TCB) is studied in a quantitative manner by monitoring the time-resolved decrease in trap phosphorescence intensity due to the propagation of a well-defined heat pulse. The excitation distribution in a single trap system, such as the X-trap in neat h 2 -TCB, is discussed in terms of the energy partition function relating the temperature dependence of the trap phosphorescence intensity to the trap depth, exciton bandwidth, and the number of exciton band states. In a multiple trap system, such as the hd and h 2 isotopic traps in d 2 -TCB, the excitation distribution is distinctly non-Boltzmann; yet it may be discussed in terms of a preferential energy transfer between the two trap states via the exciton band. For both trap systems, a previously developed kinetic model is presented which relates the efficiency of trap-band energy exchange to the density of band states and the trap-phonon coupling matrix elements. A bolometric technique for determining the thermal response time of the heater/crystal system is presented. The phonon mean free path in the crystal is size-limited, and the heater/crystal boundary conductance is reasonably close to previously reported values. The theory of heat pulse phonon spectroscopy is presented and discussed in terms of black-body phonon radiation

  5. Properties of the radicals formed by one-electron oxidation of acetaminophen - a pulse radiolysis study

    Energy Technology Data Exchange (ETDEWEB)

    Bisby, R H; Tabassum, N

    1988-07-15

    The semi-iminoquinone radical of acetaminophen, which has previously been proposed as a possible hepatotoxic intermediate in the cytochrome P-450 catalysed oxidation of acetaminophen, has been generated and studied by pulse radiolysis. In the absence of other reactive solutes, the radical decays rapidly by second order kinetics with a rate constant (2k/sub 2/) of (2.2 +- 0.4) x 10/sup 9/ M/sup -1/ sec/sup -1/. In alkaline solutions the radical deprotonates with a pK of 11.1 +- 0.1 to form a radical-anion. The acetaminophen radical-anion reacts with resorcinol at high pH values, leading to the formation of a transient equilibrium from which the one-electron reduction potential of the semi-iminoquinone radical of acetaminophen is estimated to be + 0.707 +- 0.01 V at pH 7. This value predicts that acetaminophen should be oxidised by thiyl radicals. This was confirmed by pulse radiolysis experiments for reaction of the cysteinyl radical, for which rate constants of 7 x 10/sup 6/ M/sup -1/ sec/sup -1/ at pH7 and 2.7 x 10/sup 8/ M/sup -1/ sec/sup -1/ at pH 11.3 were obtained. The reaction of O/sub 2/ with the acetaminophen semi-iminoquinone radical could not be detected by pulse radiolysis, and alternative mechanisms for superoxide radical formation are discussed.

  6. Histologic evaluation of skin damage after overlapping and nonoverlapping flashlamp pumped pulsed dye laser pulses: A study on normal human skin as a model for port wine stains

    NARCIS (Netherlands)

    Koster, P. H.; van der Horst, C. M.; van Gemert, M. J.; van der Wal, A. C.

    2001-01-01

    BACKGROUND AND OBJECTIVE: In the treatment of port wine stains (PWS) with the flashlamp pumped pulsed dye laser (FPPDL), no consensus exists about overlapping of pulses. The advantage of overlapping pulses is homogeneous lightening of the PWS; the risk is redundant tissue damage. The aim of this

  7. Pulsed power

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    The key element of our pulsed power program is concentration of power in time and space by suppression of breakdown in dielectrics and in vacuum. Magnetically insulated vacuum transmission lines and magnetic suppression of insulator flashover have continued as the main reserch directions. Vacuum insulated line studies at Physics International have been expanded and a test bed at Sandia, called MITE (Magnetically Insulated Transmission Experiment), is under development. The choice for the baseline EBFA design will depend on the outcome of these studies and should be made in July 1977. The slow and intermediate speed pulsed power approaches to EBFA will be based on Proto I and Proto II results and several of the projected EBFA subsystems are presently being tested in Proto II. A further stage of power concentration, within the vacuum diode itself, would considerably ease the burden on dielectrics; methods of power multiplication involving magnetically imploded plasmas are being considered and tests have begun using the Ripple III apparatus

  8. Semianalytical study of the propagation of an ultrastrong femtosecond laser pulse in a plasma with ultrarelativistic electron jitter

    Energy Technology Data Exchange (ETDEWEB)

    Jovanović, Dušan, E-mail: dusan.jovanovic@ipb.ac.rs [Institute of Physics, University of Belgrade, Pregrevica 118, 11080 Belgrade, Zemun (Serbia); Fedele, Renato, E-mail: renato.fedele@na.infn.it [Dipartimento di Fisica, Università di Napoli “Federico II,” M.S. Angelo, Napoli (Italy); INFN Sezione di Napoli, Complesso Universitario di M.S. Angelo, Napoli (Italy); Belić, Milivoj, E-mail: milivoj.belic@qatar.tamu.edu [Texas A and M University at Qatar, P.O. Box 23874, Doha (Qatar); De Nicola, Sergio, E-mail: sergio.denicola@spin.cnr.it [SPIN-CNR, Complesso Universitario di M.S. Angelo, Napoli (Italy)

    2015-04-15

    The interaction of a multi-petawatt, pancake-shaped laser pulse with an unmagnetized plasma is studied analytically and numerically in a regime with ultrarelativistic electron jitter velocities, in which the plasma electrons are almost completely expelled from the pulse region. The study is applied to a laser wakefield acceleration scheme with specifications that may be available in the next generation of Ti:Sa lasers and with the use of recently developed pulse compression techniques. A set of novel nonlinear equations is derived using a three-timescale description, with an intermediate timescale associated with the nonlinear phase of the electromagnetic wave and with the spatial bending of its wave front. They describe, on an equal footing, both the strong and the moderate laser intensity regimes, pertinent to the core and to the edges of the pulse. These have fundamentally different dispersive properties since in the core the electrons are almost completely expelled by a very strong ponderomotive force, and the electromagnetic wave packet is imbedded in a vacuum channel, thus having (almost) linear properties. Conversely, at the pulse edges, the laser amplitude is smaller, and the wave is weakly nonlinear and dispersive. New nonlinear terms in the wave equation, introduced by the nonlinear phase, describe without the violation of imposed scaling laws a smooth transition to a nondispersive electromagnetic wave at very large intensities and a simultaneous saturation of the (initially cubic) nonlocal nonlinearity. The temporal evolution of the laser pulse is studied both analytically and by numerically solving the model equations in a two-dimensional geometry, with the spot diameter presently used in some laser acceleration experiments. The most stable initial pulse length is estimated to exceed ≳1.5–2 μm. Moderate stretching of the pulse in the direction of propagation is observed, followed by the development of a vacuum channel and of a very large

  9. Development of response transforms from comparative study of commercial pulsed neutron capture logging systems

    International Nuclear Information System (INIS)

    Salaita, G.N.; Youngblood, W.E.

    1991-01-01

    This paper reports that the absence of a common calibration facility to ascertain the accuracy of commercial pulsed neutron capture logging systems, coupled with the desire for more accurate saturation determination from time-lapse logs, prompted Saudi Aramco to carry out this comparative study. Three generations of Schlumberger's Thermal Decay Time (TDT) logging devices, viz., TDT-K, TDT-M, and TDT-P along with Atlas Wireline PDK-100 system were run in an Aramco well. The wellbore 8-1/2 inch with 7-inch casing-penetrated clean sand, shaly sand, and shale streaks sequence as exhibited by the open hole natural gamma ray log. initially, the wellbore fluid was diesel. The fluid was then changed to brines of 42-kppm and 176-kppm NACl, respectively. Three repeat passes at a logging speed of 900 ft/hr were obtained by each device for each of the three borehole liquids. In the case of PDK-100, a second set of log runs was obtained at 1800 ft/hr. The results of this extensive comparative study have increased the author's understanding of the borehole liquid and the diffusion effects on the response of pulsed neutron capture logging systems and also on the relative accuracy and precision of measured formation thermal neutron capture cross section by each system

  10. Long-Pulse Operation and High-Energy Particle Confinement Study in ICRF Heating of LHD

    International Nuclear Information System (INIS)

    Mutoh, Takashi; Kumazawa, Ryuhei; Seki, Tetsuo

    2004-01-01

    Long-pulse operation and high-energy particle confinement properties were studied using ion cyclotron range of frequency (ICRF) heating for the Large Helical Device. For the minority-ion mode, ions with energies up to 500 keV were observed by concentrating the ICRF heating power near the plasma axis. The confinement of high-energy particles was studied using the power-modulation technique. This confirmed that the confinement of high-energy particles was better with the inward-shifted configuration than with the normal configuration. This behavior was the same for bulk plasma confinement. Long-pulse operation for more than 2 min was achieved during the experimental program in 2002. This was mainly due to better confinement of the helically trapped particles and accumulation of fewer impurities in the region of the plasma core, in conjunction with substantial hardware improvements. Currently, the plasma operation time is limited by an unexpected density rise due to outgassing from the chamber materials. The temperature of the local carbon plates of the divertor exceeded 400 deg, C, and a charge-coupled device camera observed the hot spots. The hot spot pattern was well explained by a calculation of the accelerated-particle orbits, and those accelerated particles came from outside the plasma near the ICRF antenna

  11. Effect of intense pulsed light on immature burn scars: A clinical study

    Directory of Open Access Journals (Sweden)

    Arindam Sarkar

    2014-01-01

    Full Text Available Introduction: As intense pulsed light (IPL is widely used to treat cutaneous vascular malformations and also used as non-ablative skin rejunuvation to remodel the skin collagen. A study has been undertaken to gauze the effect of IPL on immature burn scars with regard to vascularity, pliability and height. Materials and Methods: This study was conducted between June 2013 and May 2014, among patients with immature burn scars that healed conservatively within 2 months. Photographic evidence of appearance of scars and grading and rating was done with Vancouver Scar Scale parameters. Ratings were done for both case and control scar after the completion of four IPL treatment sessions and were compared. Results: Out of the 19 cases, vascularity, pliability and height improved significantly (P < 0.05 in 13, 14 and 11 scars respectively following IPL treatment. Conclusions: Intense pulsed light was well-tolerated by patients, caused good improvement in terms of vascularity, pliability, and height of immature burn scar.

  12. Pulse Generator

    Science.gov (United States)

    Greer, Lawrence (Inventor)

    2017-01-01

    An apparatus and a computer-implemented method for generating pulses synchronized to a rising edge of a tachometer signal from rotating machinery are disclosed. For example, in one embodiment, a pulse state machine may be configured to generate a plurality of pulses, and a period state machine may be configured to determine a period for each of the plurality of pulses.

  13. Study on two phase flow characteristics in annular pulsed extraction column with different ratio of annular width to column diameter

    International Nuclear Information System (INIS)

    Qin Wei; Dai Youyuan; Wang Jiading

    1994-01-01

    Annular pulsed extraction column can successfully provide large throughput and can be made critically safe for fuel reprocessing. This investigation is to study the two phase flow characteristics in annular pulsed extraction column with four different annular width. 30% TBP (in kerosene)-water is used (water as continuous phase). Results show that modified Pratt correlation is valid under the experimental operation conditions for the annular pulsed extraction column. The characteristic velocity U K decreased with the increase of energy input and increased with the increase of the ratio of annular width to column diameter. Flooding velocity correlation is suggested. The deviation of the calculated values from the experimental data is within +20% for four annular width in a pulsed extraction column

  14. Warm dense matter study and pulsed-power developments for X-pinch equipment in Nagaoka University of Technology

    International Nuclear Information System (INIS)

    Sasaki, Toru; Miki, Yasutoshi; Tachinami, Fumitaka; Saito, Hirotaka; Takahashi, Takuya; Anzai, Nobuyuki; Kikuchi, Takashi; Aso, Tsukasa; Harada, Nob.

    2014-01-01

    In order to explore high energy density physics, we have performed WDM experiment by using several pulsed-power devices. To generate well-defined warm dense state for evaluating electrical conductivity and its properties, we have proposed an isochoric heating of foamed metal by using pulsed-power discharge. The proposed technique yields the electrical conductivity of warm dense matter with a well-defined temperature. To observe the warm dense matter, a pulsed-power generator based on a pulse-forming-network (PFN) was studied toward generating an intense point-spot-like X-ray source from X-pinch technique. From comparison of the designing and the actual inductances of the X-pinch system, the actual inductance of X-pinch system is 3.5 times higher than the designing inductance. To reduce the total inductance of X-pinch system, we will modify the gap switch system such as multi spake gap

  15. Diffraction properties study of reflection volume holographic grating in dispersive photorefractive material under ultra-short pulse readout

    Energy Technology Data Exchange (ETDEWEB)

    Yi Yingyan; Liu Deming; Liu Hairong, E-mail: yiyingyan0410@163.com [Wuhan National Laboratory for Optoelectronics, School of Optoelectronic Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074 (China)

    2011-02-01

    Based on the modified Kogelnik diffraction efficiency equation, we study the diffraction intensity spectrum and the total diffraction efficiency of reflection volume holographic gratings in photorefractive media. Taking photorefractive LiNbO{sub 3} crystal as an example, the effect of the grating parameters and the pulse width on the diffraction properties is presented under the influence of crystal material dispersion. Under the combined effects, the diffraction pulse profiles and the total diffraction efficiency are compared with and without crystal material dispersion. The results show that the dispersion will decrease the diffraction intensity. Moreover, when pulse width is smaller or the grating spacing and the grating thickness are larger, the influence of dispersion on diffraction is large. The results of our paper can be used in pulse shaping applications.

  16. Study of the mechanisms of flux enhancement through hairless mouse skin by pulsed DC iontophoresis

    International Nuclear Information System (INIS)

    Pikal, M.J.; Shah, S.

    1991-01-01

    Enhanced iontophoretic transport using pulsed DC is usually explained by citing the observed decrease in skin resistance caused by an increase in AC pulse frequency at very small currents. Alternately, it has been suggested that the on-to-off nature of pulsed DC imparts an impact energy to the fluid, thereby increasing transport. This report provides a test of these mechanisms for enhanced delivery via pulsed iontophoresis. The DC resistance of hairless mouse skin during continuous and pulsed DC iontophoresis is measured as a function of time for selected pulse frequencies and duty cycles using current densities ranging from 0.1 to 1.0 mA/cm2. As a test of the impact energy mechanism, the iontophoretic transport of 14C-glucose measured with pulsed DC is compared with similar data obtained previously using continuous DC. It is suggested that pulsed current can yield lower resistance and enhanced drug delivery provided that (a) the steady-state current during the on phase of the pulse is very small and (b) the frequency is low enough to allow depolarization of the skin during the off phase of the pulse. The glucose transport results suggest that the impact energy concept does not apply to iontophoresis

  17. Potentiostatic pulse-deposition of calcium phosphate on magnesium alloy for temporary implant applications--an in vitro corrosion study.

    Science.gov (United States)

    Kannan, M Bobby; Wallipa, O

    2013-03-01

    In this study, a magnesium alloy (AZ91) was coated with calcium phosphate using potentiostatic pulse-potential and constant-potential methods and the in vitro corrosion behaviour of the coated samples was compared with the bare metal. In vitro corrosion studies were carried out using electrochemical impedance spectroscopy and potentiodynamic polarization in simulated body fluid (SBF) at 37 °C. Calcium phosphate coatings enhanced the corrosion resistance of the alloy, however, the pulse-potential coating performed better than the constant-potential coating. The pulse-potential coating exhibited ~3 times higher polarization resistance than that of the constant-potential coating. The corrosion current density obtained from the potentiodynamic polarization curves was significantly less (~60%) for the pulse-deposition coating as compared to the constant-potential coating. Post-corrosion analysis revealed only slight corrosion on the pulse-potential coating, whereas the constant-potential coating exhibited a large number of corrosion particles attached to the coating. The better in vitro corrosion performance of the pulse-potential coating can be attributed to the closely packed calcium phosphate particles. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. Development of a high energy pulsed plasma simulator for the study of liquid lithium trenches

    International Nuclear Information System (INIS)

    Jung, S.; Christenson, M.; Curreli, D.; Bryniarski, C.; Andruczyk, D.; Ruzic, D.N.

    2014-01-01

    Highlights: • A pulse device for a liquid lithium trench study is developed. • It consists of a coaxial plasma gun, a theta pinch, and guiding magnets. • A large energy enhancement is observed with the use of the plasma gun. • A further increase in energy and velocity is observed with the theta pinch. - Abstract: To simulate detrimental events in a tokamak and provide a test-stand for a liquid-lithium infused trench (LiMIT) device [1], a pulsed plasma source utilizing a theta pinch in conjunction with a coaxial plasma accelerator has been developed. The plasma is characterized using a triple Langmuir probe, optical methods, and a calorimeter. Clear advantages have been observed with the application of a coaxial plasma accelerator as a pre-ionization source. The experimental results of the plasma gun in conjunction with the existing theta pinch show a significant improvement from the previous energy deposition by a factor of 14 or higher, resulting in a maximum energy and heat flux of 0.065 ± 0.002 MJ/m 2 and 0.43 ± 0.01 GW/m 2 . A few ways to further increase the plasma heat flux for LiMIT experiments are discussed

  19. Pulse Double-Resonance EPR Techniques for the Study of Metallobiomolecules.

    Science.gov (United States)

    Cox, Nicholas; Nalepa, Anna; Pandelia, Maria-Eirini; Lubitz, Wolfgang; Savitsky, Anton

    2015-01-01

    Electron paramagnetic resonance (EPR) spectroscopy exploits an intrinsic property of matter, namely the electron spin and its related magnetic moment. This can be oriented in a magnetic field and thus, in the classical limit, acts like a little bar magnet. Its moment will align either parallel or antiparallel to the field, giving rise to different energies (termed Zeeman splitting). Transitions between these two quantized states can be driven by incident microwave frequency radiation, analogous to NMR experiments, where radiofrequency radiation is used. However, the electron Zeeman interaction alone provides only limited information. Instead, much of the usefulness of EPR is derived from the fact that the electron spin also interacts with its local magnetic environment and thus can be used to probe structure via detection of nearby spins, e.g., NMR-active magnetic nuclei and/or other electron spin(s). The latter is exploited in spin labeling techniques, an exciting new area in the development of noncrystallographic protein structure determination. Although these interactions are often smaller than the linewidth of the EPR experiment, sophisticated pulse EPR methods allow their detection. A number of such techniques are well established today and can be broadly described as double-resonance methods, in which the electron spin is used as a reporter. Below we give a brief description of pulse EPR methods, particularly their implementation at higher magnetic fields, and how to best exploit them for studying metallobiomolecules. © 2015 Elsevier Inc. All rights reserved.

  20. Development of a high energy pulsed plasma simulator for the study of liquid lithium trenches

    Energy Technology Data Exchange (ETDEWEB)

    Jung, S., E-mail: jung73@illinois.edu [Department of Nuclear, Plasma, and Radiological Engineering, University of Illinois at Urbana-Champaign, Urbana 61801 (United States); Christenson, M.; Curreli, D. [Department of Nuclear, Plasma, and Radiological Engineering, University of Illinois at Urbana-Champaign, Urbana 61801 (United States); Bryniarski, C. [Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana 61801 (United States); Andruczyk, D.; Ruzic, D.N. [Department of Nuclear, Plasma, and Radiological Engineering, University of Illinois at Urbana-Champaign, Urbana 61801 (United States)

    2014-12-15

    Highlights: • A pulse device for a liquid lithium trench study is developed. • It consists of a coaxial plasma gun, a theta pinch, and guiding magnets. • A large energy enhancement is observed with the use of the plasma gun. • A further increase in energy and velocity is observed with the theta pinch. - Abstract: To simulate detrimental events in a tokamak and provide a test-stand for a liquid-lithium infused trench (LiMIT) device [1], a pulsed plasma source utilizing a theta pinch in conjunction with a coaxial plasma accelerator has been developed. The plasma is characterized using a triple Langmuir probe, optical methods, and a calorimeter. Clear advantages have been observed with the application of a coaxial plasma accelerator as a pre-ionization source. The experimental results of the plasma gun in conjunction with the existing theta pinch show a significant improvement from the previous energy deposition by a factor of 14 or higher, resulting in a maximum energy and heat flux of 0.065 ± 0.002 MJ/m{sup 2} and 0.43 ± 0.01 GW/m{sup 2}. A few ways to further increase the plasma heat flux for LiMIT experiments are discussed.

  1. Study on the ablation threshold induced by pulsed lasers at different wavelengths

    International Nuclear Information System (INIS)

    Torrisi, L.; Borrielli, A.; Margarone, D.

    2007-01-01

    A study of the effects induced by pulsed laser ablation on different materials as a function of the laser wavelength is presented. In particular the ablation at low laser fluence, of the order of 10 8 -10 10 W/cm 2 with ns pulse width, is investigated experimentally on different metals, semiconductors and polymers. Two theoretical models, explain the experimental results about the fluence threshold value measurements, as depending on the laser wavelength are discussed. The photothermal process is valid for the estimation of the threshold fluence for IR and visible radiation, both inducing thermal heating in metals and semiconductors through the photon-free electron energy transfer. This model is not valid for polymers. The photochemical process is valid for the estimation of the threshold fluence for UV radiation, which photon energy is higher with respect to the chemical binding energy. This radiation induces chemical bond breaking in insulators and scission and cross linking effects can be produced. This last model is not valid for metals and semiconductors

  2. Redox reactions of tocopherol monoglucoside in aqueous solutions. A pulse radiolysis study

    Energy Technology Data Exchange (ETDEWEB)

    Kapoor, S.; Mukherjee, T.; Nair, C.K.K. [Bhabha Atomic Research Centre, Mumbai (India); Kagiya, Tsutomu V. [Health Research Foundation, Kyoto (Japan)

    2002-03-01

    The reactions between tocopherol monoglucoside (TMG), a water-soluble vitamin-E derivative, with Br{sub 2}{sup {center_dot}}{sup -}, N{sub 3}{sup {center_dot}}, (SCN){sub 2}{sup {center_dot}}{sup -}, NO{sub 2}{sup {center_dot}}, OH{sup {center_dot}} and various halogenated peroxyl radicals were examined using a pulse radiolysis technique. The results demonstrate that TMG forms a stable phenoxyl radical at pH>6.8. The thus-formed phenoxyl radical shows pH-dependent decay kinetics and is disproportionated by 2nd order kinetics at pH2.3. It was observed that the TMG reactivity towards a halogenated peroxyl radical increases with the number of halogen atoms at the carbon atom having a peroxyl group. The reaction between the TMG phenoxyl radical and ascorbic acid was also examined using a pulse radiolysis technique. The results indicate that the TMG phenoxyl radical is repaired by ascorbate. Kinetic studies indicate that TMG may act as an antioxidant to repair free-radical damage to some biologically importnat compounds. The one-electron reduction potential for TMG was found to be 0.522 V{+-}0.06 vs. NHE. (author)

  3. A parametric study on the PD pulses activity within micro-cavities

    Science.gov (United States)

    Ganjovi, Alireza A.

    2016-03-01

    A two-dimensional kinetic model has been used to parametric investigation of the spark-type partial discharge pulses inside the micro-cavities. The model is based on particle-in-cell methods with Monte Carlo Collision techniques for modeling of collisions. Secondary processes like photo-emission and cathode-emission are considered. The micro-cavity may be sandwiched between two metallic conductors or two dielectrics. The discharge within the micro-cavity is studied in conjunction with the external circuit. The model is used to successfully simulate the evolution of the discharge and yield useful information about the build-up of space charge within the micro-cavity and the consequent modification of the applied electric field. The phase-space scatter plots for electrons, positive, and negative ions are obtained in order to understand the manner in which discharge progresses over time. The rise-time and the magnitude of the discharge current pulse are obtained and are seen to be affected by micro-cavity dimensions, gas pressure within the micro-cavity, and the permittivity of surrounding dielectrics. The results have been compared with existing experimental, theoretical, and computational results, wherever possible. An attempt has been made to understand the nature of the variations in terms of the physical processes involved.

  4. A quantum dynamics study of the benzopyran ring opening guided by laser pulses

    Science.gov (United States)

    Saab, Mohamad; Doriol, Loïc Joubert; Lasorne, Benjamin; Guérin, Stéphane; Gatti, Fabien

    2014-10-01

    The ring-opening photoisomerization of benzopyran, which occurs via a photochemical route involving a conical intersection, has been studied with quantum dynamics calculations using the multi-configuration time-dependent Hartree method (MCTDH). We introduce a mechanistic strategy to control the conversion of benzopyran to merocyanine with laser pulses. We use a six-dimensional model developed in a previous work for the potential energy surfaces (PES) based on an extension of the vibronic-coupling Hamiltonian model (diabatization method by ansatz), which depends on the most active degrees of freedom. The main objective of these quantum dynamics simulations is to provide a set of strategies that could help experimentalists to control the photoreactivity vs. photostability ratio (selectivity). In this work we present: (i) a pump-dump technique used to control the photostability, (ii) a two-step strategy to enhance the reactivity of the system: first, a pure vibrational excitation in the electronic ground state that prepares the system and, second, an ultraviolet excitation that brings the system to the first adiabatic electronic state; (iii) finally the effect of a non-resonant pulse (Stark effect) on the dynamics.

  5. Application of adjustable pulse lasers to studying rapid reaction kinetics of excited lanthanide complexing

    Energy Technology Data Exchange (ETDEWEB)

    Gruzdev, V.P. (Gosudarstvennyj Opticheskij Inst., Leningrad (USSR))

    1983-12-01

    Using some europium (3) ion complexes new possibilities to be opened by application of adjustable pulse lasers for studying rapid reactions of electron-excited metal ion complexing are demonstrated. The 6Zh rhodamine pulse laser is used as a source of nonequilibrium photoexcitation of an array of Eu/sup 3 +/ complexes in the luminescent kinetic spectroscopy method. The following results are obtained: for the first time the rate of reaction of acetate ion substitution for water molecules of an excited (/sup 5/D/sub 0/) ion of Eu/sup 3 +/ was measured to be (0.7+-0.2)x10/sup 7/ s/sup -1/; using direct experiments the lower limit for the rate of transition of one isomeric form of the excited Eu x EDTA complex into another one in an aqueous solution is determined to be 5x10/sup 5/ s/sup -1/ at 295 K; the kinetics of the excitation energy migration beteen aqueous solvates of Eu/sup 3 +/ and EuxEDTA complexes is investigated.

  6. Study on the exposure of spherical microtargets to a (1-3) TW iodine laser pulse

    International Nuclear Information System (INIS)

    Zaretskij, A.I.; Kirillov, G.A.; Kormer, S.B.; Kochemasov, G.G.; Murugov, V.M.; Sukharev, S.A.

    1983-01-01

    Investigations carried out at the photo dissociation iodine laser ''Iskra-4'' (PIL) with the aim of improving laser parameters and studying the interaction of laser radiation with microtargets filled with TD gas, are reviewed. PIL ''Iskra-4'' has the radiation energy maximum in the world of approximately 1.8 kJ in one beam with the light aperture approximately 60 cm, pulse duration approximately 0.8 ns, beam divergence theta approximately 0.3-0.4 mrad and the contrast more than 10 6 . A good direction of laser radiation is achieved due to . the optimization of the composition of working medium, pressure of its components, and other factors that permits to minimize the gradient of refraction index without considerable reduction of the stored energy. The problem of selecting the regime of affecting of the ''exploding shell'' type and obtaining of short duration pulses is generally considered. The assigning generator and results of experiments into irradiation of spherical microtargets filled with DT gas are described. The neutron yield of up to 10 6 neutrons in the case of 50 time volumetric compression is obtained for the first time with the aid of PIL

  7. The Feasibility and Validity of a Remote Pulse Oximetry System for Pulmonary Rehabilitation: A Pilot Study

    Directory of Open Access Journals (Sweden)

    Jonathan Tang

    2012-01-01

    Full Text Available Pulmonary rehabilitation is an effective treatment for people with chronic obstructive pulmonary disease. However, access to these services is limited especially in rural and remote areas. Telerehabilitation has the potential to deliver pulmonary rehabilitation programs to these communities. The aim of this study was threefold: to establish the technical feasibility of transmitting real-time pulse oximetry data, determine the validity of remote measurements compared to conventional face-to-face measures, and evaluate the participants’ perception of the usability of the technology. Thirty-seven healthy individuals participated in a single remote pulmonary rehabilitation exercise session, conducted using the eHAB telerehabilitation system. Validity was assessed by comparing the participant's oxygen saturation and heart rate with the data set received at the therapist’s remote location. There was an 80% exact agreement between participant and therapist data sets. The mean absolute difference and Bland and Altman’s limits of agreement fell within the minimum clinically important difference for both oxygen saturation and heart rate values. Participants found the system easy to use and felt confident that they would be able to use it at home. Remote measurement of pulse oximetry data for a pulmonary rehabilitation exercise session was feasible and valid when compared to conventional face-to-face methods.

  8. Numerical studies of acceleration of thorium ions by a laser pulse of ultra-relativistic intensity

    Directory of Open Access Journals (Sweden)

    Domanski Jaroslaw

    2018-01-01

    Full Text Available One of the key scientific projects of ELI-Nuclear Physics is to study the production of extremely neutron-rich nuclides by a new reaction mechanism called fission-fusion using laser-accelerated thorium (232Th ions. This research is of crucial importance for understanding the nature of the creation of heavy elements in the Universe; however, they require Th ion beams of very high beam fluencies and intensities which are inaccessible in conventional accelerators. This contribution is a first attempt to investigate the possibility of the generation of intense Th ion beams by a fs laser pulse of ultra-relativistic intensity. The investigation was performed with the use of fully electromagnetic relativistic particle-in-cell code. A sub-μm thorium target was irradiated by a circularly polarized 20-fs laser pulse of intensity up to 1023 W/cm2, predicted to be attainable at ELI-NP. At the laser intensity ~ 1023 W/cm2 and an optimum target thickness, the maximum energies of Th ions approach 9.3 GeV, the ion beam intensity is > 1020 W/cm2 and the total ion fluence reaches values ~ 1019 ions/cm2. The last two values are much higher than attainable in conventional accelerators and are fairly promising for the planned ELI-NP experiment.

  9. Defect studies of thin ZnO films prepared by pulsed laser deposition

    International Nuclear Information System (INIS)

    Vlček, M; Čížek, J; Procházka, I; Novotný, M; Bulíř, J; Lančok, J; Anwand, W; Brauer, G; Mosnier, J-P

    2014-01-01

    Thin ZnO films were grown by pulsed laser deposition on four different substrates: sapphire (0 0 0 1), MgO (1 0 0), fused silica and nanocrystalline synthetic diamond. Defect studies by slow positron implantation spectroscopy (SPIS) revealed significantly higher concentration of defects in the studied films when compared to a bulk ZnO single crystal. The concentration of defects in the films deposited on single crystal sapphire and MgO substrates is higher than in the films deposited on amorphous fused silica substrate and nanocrystalline synthetic diamond. Furthermore, the effect of deposition temperature on film quality was investigated in ZnO films deposited on synthetic diamond substrates. Defect studies performed by SPIS revealed that the concentration of defects firstly decreases with increasing deposition temperature, but at too high deposition temperatures it increases again. The lowest concentration of defects was found in the film deposited at 450° C.

  10. Construction and temporal behaviour study of multi RLC intense light pulses for dermatological applications.

    Science.gov (United States)

    Hamoudi, Walid K; Ismail, Raid A; Shakir, Hussein A

    2017-10-01

    Driving a flash lamp in an intense pulsed light system requires a high-voltage DC power supply, capacitive energy storage and a flash lamp triggering unit. Single, double, triple and quadruple-mesh discharge and triggering circuits were constructed to provide intense light pulses of variable energy and time durations. The system was treated as [Formula: see text] circuit in some cases and [Formula: see text] circuit in others with a light pulse profile following the temporal behaviour of the exciting current pulse. Distributing the energy delivered to one lamp onto a number of LC meshes permitted longer current pulses, and consequently increased the light pulse length. Positive results were obtained when using the system to treat skin wrinkles.

  11. Studies on the transmission and processing of pulse-shaped signals from nuclear radiation detectors using methods of systems theory

    International Nuclear Information System (INIS)

    Spillekothen, H.G.

    2007-01-01

    Using methods of the systems theory of electronic communications and theoretical electrical science, this study describes the transmission of pulse-shaped signals from nuclear radiation detectors from the detector over ''electrically long lines'' (cables) to the output of the first pulse amplifier. The example of pulses from BF 3 -proportional counters shows, using the Fourier transformation, that pulses from radiation detectors contain a frequency spectrum ranging well above 10 8 Hz. If these pulses are transmitted to the first amplifier over a line length of several meters, the laws of the theory of transmission lines must be taken into account to avoid false signals caused by reflections. In the example, line equations are applied and the influence of the line and the terminating impedance is demonstrated. The influence of the frequency response ν(ω) and the phase response δ(ω) of the amplifier is also considered in the sample calculation. The methods presented make it possible to analyze and optimize the transmission and amplification of signals from radiation detectors. Close agreement emerges between empirically observed and calculated pulse shapes. (orig.)

  12. Studies on the Pulse Rate, Pedometer Count and Satisfactoin Degree at Various Exercise

    OpenAIRE

    小原, 史朗

    2004-01-01

    This investigation examined whether free exercise of students became good stimulation of breathing circulation function from relation of pulse rate and pedometer count. And, I examined it on satisfaction degree after exercise. Object person was 432 man students (total of 1391) and 94 woman students (total of 472). As for relation of pulse rate and pedometer count, statistical meaning was recognized by man and women. The exercise that a pulse rate and pedometer count were high together seemed ...

  13. Experimental Study of SO2 Removal by Pulsed DBD Along with the Application of Magnetic Field

    International Nuclear Information System (INIS)

    Rong Mingzhe; Liu Dingxin; Wang Xiaohua; Wang Junhua

    2007-01-01

    Dielectric barrier discharge (DBD) for SO 2 removal from indoor air is investigated. In order to improve the removal efficiency, two novel methods are combined in this paper, namely by applying a pulsed driving voltage with nanosecond rising time and applying a magnetic field. For SO 2 removal efficiency, different matches of electric field and magnetic field are discussed. And nanosecond rising edge pulsed power supply and microsecond rising edge pulsed power supply are compared. It can be concluded that a pulsed DBD with nanosecond rising edge should be adopted, and electrical field and magnetic field should be applied in an appropriate match

  14. Multiplex Outputs ns Grade High-voltage Fast Pulse Generator Study

    International Nuclear Information System (INIS)

    Wang Xin; Chen Kenan

    2009-01-01

    Using a double-grid hydrogen thyratron, a fast pulse generator with four outputs, high-voltage, low jitter, was made to use at special occasion.In this paper, the basic structure of pulser, switching theory and double-grid driving of hydrogen thyratron was introduced, and also, the effects of grids driving pulses characteristics, the delay between too grids driving, the reservoir heater voltage and cathode heater voltage on the output are carefully examined in experiments. The pulse generator with four outputs was made to producing pulses with amplitude up to 4 kV, rise-time less than 15 ns and jitter less than 3 ns. (authors)

  15. Study of 18-Pulse Rectifier Utilizing Hexagon Connected 3-Phase to 9-Phase Transformer

    Directory of Open Access Journals (Sweden)

    Ahmad Saudi Samosir

    2008-04-01

    Full Text Available The 18-pulse converter, using Y or -connected differential autotransformer, is very interesting since it allows natural high power factor correction. The lowest input current harmonic components are the 17th and 19th. The Transformer is designed to feed three six-pulse bridge rectifiers displaced in phase by 200. This paper present a high power factor three-phase rectifier bases on 3-phase to 9-phase transformer and 18-pulse rectifier. The 9-phase polygon-connected transformer followed by 18-pulse diode rectifiers ensures the fundamental concept of natural power factor correction. Simulation results to verify the proposed concept are shown in this paper.

  16. Studies on widely tunable ultra-short laser pulses using energy transfer distributed feedback dye laser

    International Nuclear Information System (INIS)

    Ahamed, M.B.; Ramalingam, A.; Palanisamy, P.K.

    2003-01-01

    This paper presents both theoretical and experimental study of the characteristics of Nd: YAG laser pumped energy transfer distributed feedback dye laser (ETDFDL). Using theoretical model proposed, the behavior of ETDFDL such as the characteristics of donor DFDL, the acceptor DFDL, the dependence of their pulse width and output power on donor-acceptor concentrations and pump power are studied for dye mixture Rhodamine 6G and Cresyl Violet in detail. Experimentally using prism-dye cell configuration, the ETDFDL output is obtained and the output energy of DFDL is measured at the emission peaks of donor and acceptor dyes for different pump powers and donor-acceptor concentrations. In addition, the DFDL linewidth measurement has been carried out at the lasing wavelengths of the donor and acceptor dyes using Fabry-Perot etalon and the tunability of DFDL is measured to be in the wavelength range of 545-680 nm

  17. Photoelectric properties of GaAs materials studied by pulsed laser techniques

    International Nuclear Information System (INIS)

    Aguir, Khalifa

    1981-01-01

    This research thesis addressed the photoelectric properties of single-crystal or epitaxial GaAs (N doped or P doped) materials. The objective is to characterize and to improve the electric quality of these materials and associated components, notably for the production of high performance solar cells for ground-based or space-based applications. More particularly, this research aimed at using an excitation by a pulsed laser to analyse recombination and trapping properties of carriers created by photo-excitation, and also at studying the effect of low doses of particle irradiation on the carrier properties. Thus, the author describes conduction characteristics of two different N-type epitaxial layers, discusses carrier excitation and recombination processes which may occur in semiconductors, and proposes an overview of trapping phenomena. Photoelectric properties of the considered epitaxial layers are then studied and discussed

  18. Moessbauer and calorimetric studies of portland cement hydration in the presence of black gram pulse

    International Nuclear Information System (INIS)

    Rai, Sarita; Kurian, Sajith; Dwivedi, V. N.; Das, S. S.; Singh, N. B.; Gajbhiye, N. S.

    2009-01-01

    Effect of different concentrations of naturally occurring admixture in the form of fine powder of black gram pulse (BGP) on the hydration of Portland cement was studied by isothermal calorimetry and 57 Fe Moessbauer spectroscopy. The spectra were recorded for anhydrous cement and the hydration products at room temperature and 77 K. In the presence of BGP, the spectra showed superparamagnetic doublets at room temperature and the sextet at 77 K, due to the presence of fine particles of iron containing component. Moessbauer studies of hydration products confirmed the formation of nanosize hydration products containing Fe 3+ . The isomer shift (δ) and the quadrupole splitting (ΔE Q ) values of C 4 AF in the cement confirmed iron in an octahedral and tetrahedral environment with +3 oxidation state. The high value of quadrupole splitting showed the high asymmetry of the electron environment around the iron atom. The overall mechanism of the hydration of cement in presence of BGP is discussed.

  19. Pulse to pulse klystron diagnosis system

    International Nuclear Information System (INIS)

    Nowak, J.; Davidson, V.; Genova, L.; Johnson, R.; Reagan, D.

    1981-03-01

    This report describes a system used to study the behavior of SLAC high powered klystrons operating with a twice normal pulse width of 5 μs. At present, up to eight of the klystrons installed along the accelerator can be operated with long pulses and monitored by this system. The report will also discuss some of the recent findings and investigations

  20. The association between pulse wave velocity and cognitive function: the Sydney Memory and Ageing Study.

    Directory of Open Access Journals (Sweden)

    Joel Singer

    Full Text Available OBJECTIVES: Pulse wave velocity (PWV is a measure of arterial stiffness and its increase with ageing has been associated with damage to cerebral microvessels and cognitive impairment. This study examined the relationship between carotid-femoral PWV and specific domains of cognitive function in a non-demented elderly sample. METHOD: Data were drawn from the Sydney Memory and Ageing Study, a cohort study of non-demented community-dwelling individuals aged 70-90 years, assessed in successive waves two years apart. In Wave 2, PWV and cognitive function were measured in 319 participants. Linear regression was used to analyse the cross-sectional relationship between arterial stiffness and cognitive function in the whole sample, and separately for men and women. Analysis of covariance was used to assess potential differences in cognition between subjects with PWV measurements in the top and bottom tertiles of the cohort. Covariates were age, education, body mass index, pulse rate, systolic blood pressure, cholesterol, depression, alcohol, smoking, hormone replacement therapy, apolipoprotein E ε4 genotype, use of anti-hypertensive medications, history of stroke, transient ischemic attack, myocardial infarction, angina, diabetes, and also sex for the whole sample analyses. RESULTS: There was no association between PWV and cognition after Bonferroni correction for multiple testing. When examining this association for males and females separately, an association was found in males, with higher PWV being associated with lower global cognition and memory, however, a significant difference between PWV and cognition between males and females was not found. CONCLUSION: A higher level of PWV was not associated with lower cognitive function in the whole sample.

  1. Pilot Study: Estimation of Stroke Volume and Cardiac Output from Pulse Wave Velocity.

    Directory of Open Access Journals (Sweden)

    Yurie Obata

    Full Text Available Transesophageal echocardiography (TEE is increasingly replacing thermodilution pulmonary artery catheters to assess hemodynamics in patients at high risk for cardiovascular morbidity. However, one of the drawbacks of TEE compared to pulmonary artery catheters is the inability to measure real time stroke volume (SV and cardiac output (CO continuously. The aim of the present proof of concept study was to validate a novel method of SV estimation, based on pulse wave velocity (PWV in patients undergoing cardiac surgery.This is a retrospective observational study. We measured pulse transit time by superimposing the radial arterial waveform onto the continuous wave Doppler waveform of the left ventricular outflow tract, and calculated SV (SVPWV using the transformed Bramwell-Hill equation. The SV measured by TEE (SVTEE was used as a reference.A total of 190 paired SV were measured from 28 patients. A strong correlation was observed between SVPWV and SVTEE with the coefficient of determination (R2 of 0.71. A mean difference between the two (bias was 3.70 ml with the limits of agreement ranging from -20.33 to 27.73 ml and a percentage error of 27.4% based on a Bland-Altman analysis. The concordance rate of two methods was 85.0% based on a four-quadrant plot. The angular concordance rate was 85.9% with radial limits of agreement (the radial sector that contained 95% of the data points of ± 41.5 degrees based on a polar plot.PWV based SV estimation yields reasonable agreement with SV measured by TEE. Further studies are required to assess its utility in different clinical situations.

  2. The association between pulse wave velocity and cognitive function: the Sydney Memory and Ageing Study.

    Science.gov (United States)

    Singer, Joel; Trollor, Julian N; Crawford, John; O'Rourke, Michael F; Baune, Bernhard T; Brodaty, Henry; Samaras, Katherine; Kochan, Nicole A; Campbell, Lesley; Sachdev, Perminder S; Smith, Evelyn

    2013-01-01

    Pulse wave velocity (PWV) is a measure of arterial stiffness and its increase with ageing has been associated with damage to cerebral microvessels and cognitive impairment. This study examined the relationship between carotid-femoral PWV and specific domains of cognitive function in a non-demented elderly sample. Data were drawn from the Sydney Memory and Ageing Study, a cohort study of non-demented community-dwelling individuals aged 70-90 years, assessed in successive waves two years apart. In Wave 2, PWV and cognitive function were measured in 319 participants. Linear regression was used to analyse the cross-sectional relationship between arterial stiffness and cognitive function in the whole sample, and separately for men and women. Analysis of covariance was used to assess potential differences in cognition between subjects with PWV measurements in the top and bottom tertiles of the cohort. Covariates were age, education, body mass index, pulse rate, systolic blood pressure, cholesterol, depression, alcohol, smoking, hormone replacement therapy, apolipoprotein E ε4 genotype, use of anti-hypertensive medications, history of stroke, transient ischemic attack, myocardial infarction, angina, diabetes, and also sex for the whole sample analyses. There was no association between PWV and cognition after Bonferroni correction for multiple testing. When examining this association for males and females separately, an association was found in males, with higher PWV being associated with lower global cognition and memory, however, a significant difference between PWV and cognition between males and females was not found. A higher level of PWV was not associated with lower cognitive function in the whole sample.

  3. Particle acceleration by electromagnetic pulses

    International Nuclear Information System (INIS)

    Lai, H.M.

    1982-01-01

    Particle interaction with plane electromagnetic pulses is studied. It is shown that particle acceleration by a wavy pulse, depending on the shape of the pulse, may not be small. Further, a diffusive-type particle acceleration by multiple weak pulses is described and discussed. (author)

  4. Positron annihilation in a metal-oxide semiconductor studied by using a pulsed monoenergetic positron beam

    Science.gov (United States)

    Uedono, A.; Wei, L.; Tanigawa, S.; Suzuki, R.; Ohgaki, H.; Mikado, T.; Ohji, Y.

    1993-12-01

    The positron annihilation in a metal-oxide semiconductor was studied by using a pulsed monoenergetic positron beam. Lifetime spectra of positrons were measured as a function of incident positron energy for a polycrystalline Si(100 nm)/SiO2(400 nm)/Si specimen. Applying a gate voltage between the polycrystalline Si film and the Si substrate, positrons implanted into the specimen were accumulated at the SiO2/Si interface. From the measurements, it was found that the annihilation probability of ortho-positronium (ortho-Ps) drastically decreased at the SiO2/Si interface. The observed inhibition of the Ps formation was attributed to an interaction between positrons and defects at the SiO2/Si interface.

  5. Pulse radiolytic study of alpha-tocopherol radical mechanisms in ethanolic solution

    International Nuclear Information System (INIS)

    Jore, D.; Patterson, L.K.; Ferradini, C.

    1986-01-01

    Pulse radiolytic studies of alpha-tocopherol (alpha TH) oxidation-reduction processes were carried out with low doses (5 Gy) of high-energy electrons in O 2 -, N 2 -, and air-saturated ethanolic solutions. Depending on the concentration of oxygen in solution, two different radicals, A . and B ., were observed. The first, A ., was obtained under N 2 and results from alpha TH reaction with solvated electron (k alpha TH + e-solv = 3.4 X 10(8) mol-1 liter s-1) and with H 3 C-CH-OH, (R.) (k alpha TH + R. = 5 X 10(5) mol-1 liter s-1). B., observed under O 2 , is produced by alpha TH reaction with RO 2 . peroxyl radicals (k alpha TH + RO 2 . = 9.5 X 10(4) mol-1 liter s-1)

  6. A study of the ion species dependence of [chi][sub e] by heat pulse propagation

    Energy Technology Data Exchange (ETDEWEB)

    Giannone, L.; Mertens, V; Wagner, F [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Kraemer-Flecken, A; Waidmann, G [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Plasmaphysik; Riedel, K [New York Univ., NY (United States). Courant Inst. of Mathematical Sciences

    1991-01-01

    An investigation of the isotope dependence of [chi][sub e] on Asdex revealed that the values of [chi][sub e] in hydrogen and deuterium were the same within the limits of experimental accuracy. This study in hydrogen, deuterium and helium has been continued on Textor. The 11 channel ECE diagnostic measures the temperature perturbations generated by sawtooth crashes in an ohmically heated plasma. Averaging over the one second flat top phase improves the signal to noise ratio to the extent that differences in the radial profile of [chi][sub e] are able to be inferred. Even though the values of [chi][sub e] found in each of the three gases are greater than the values calculated from power balance, the basic relationship between the energy confinement time and the value of [chi][sub e] deduced by heat pulse propagation can still be explored. (author) 7 refs. 4 figs.

  7. A study of the ion species dependence of χe by heat pulse propagation

    International Nuclear Information System (INIS)

    Giannone, L.; Mertens, V.; Wagner, F.; Kraemer-Flecken, A.; Waidmann, G.; Riedel, K.

    1991-01-01

    An investigation of the isotope dependence of χ ε on ASDEX revealed that the values of χ ε in hydrogen and deuterium were the same within the limits of experimental accuracy. This study in hydrogen, deuterium and helium has been continued on TEXTOR. The 11 channel ECE diagnostic measures the temperature perturbations generated by sawtooth crashes in an ohmically heated plasma. Averaging over the one second flat top phase improves the signal to noise ratio to the extent that differences in the radial profile of χ ε are able to be inferred. Even though the values of χ ε found in each of the three gases are greater than the values calculated from power balance, the basic relationship between the energy confinement time and the value of χ ε deduced by heat pulse propagation can still be explored. (orig.)

  8. A study of the ion species dependence of χe by heat pulse propagation

    International Nuclear Information System (INIS)

    Giannone, L.; Mertens, V.; Wagner, F.; Kraemer-Flecken, A.; Waidmann, G.; Riedel, K.

    1991-01-01

    An investigation of the isotope dependence of χ e on Asdex revealed that the values of χ e in hydrogen and deuterium were the same within the limits of experimental accuracy. This study in hydrogen, deuterium and helium has been continued on Textor. The 11 channel ECE diagnostic measures the temperature perturbations generated by sawtooth crashes in an ohmically heated plasma. Averaging over the one second flat top phase improves the signal to noise ratio to the extent that differences in the radial profile of χ e are able to be inferred. Even though the values of χ e found in each of the three gases are greater than the values calculated from power balance, the basic relationship between the energy confinement time and the value of χ e deduced by heat pulse propagation can still be explored. (author) 7 refs. 4 figs

  9. Study of the diffusion of some emulsions in the human skin by pulsed photoacoustic spectroscopy

    International Nuclear Information System (INIS)

    Lahjomri, F; Benamar, N; Chatri, E; Leblanc, R M

    2003-01-01

    We previously used pulsed photoacoustic spectroscopy (PPAS) to quantify sunscreen diffusion into human skin, and suggested a methodology to evaluate the time and the depth diffusion profile. These results were obtained by the analysis of the photoacoustic maximum response signal P max decrease, the time delay t max and the Fourier transform representation of the photoacoustic signal. In this study we present the results obtained for diffusion of four typical emulsions used in sunscreen compositions that show, for the first time, a particular behaviour for one of these emulsions due to a chemical reaction inside the skin during the diffusion process. This result provides a particularly interesting technique through the PPAS, to evaluate in situ the eventual chemical reactions that can occur during drug diffusion into human skin

  10. Ignition Study on a Rotary-valved Air-breathing Pulse Detonation Engine

    Science.gov (United States)

    Wu, Yuwen; Han, Qixiang; Shen, Yujia; Zhao, Wei

    2017-05-01

    In the present study, the ignition effect on detonation initiation was investigated in the air-breathing pulse detonation engine. Two kinds of fuel injection and ignition methods were applied. For one method, fuel and air was pre-mixed outside the PDE and then injected into the detonation tube. The droplet sizes of mixtures were measured. An annular cavity was used as the ignition section. For the other method, fuel-air mixtures were mixed inside the PDE, and a pre-combustor was utilized as the ignition source. At firing frequency of 20 Hz, transition to detonation was obtained. Experimental results indicated that the ignition position and initial flame acceleration had important effects on the deflagration-to-detonation transition.

  11. One-electron reduction of anthraquinone sulphonates: a pulse radiolysis study

    International Nuclear Information System (INIS)

    Pal, H.; Palit, D.K.; Mukherjee, T.; Mittal, J.P.

    1991-01-01

    Semiquinone free radicals, derived from 2-sulphonate, 1,5-disulphonate and 2,6-disulphonate derivatives of 9,10-anthraquinone, have been studied using pulse radiolysis and kinetic absorption spectrophotometry techniques. Spectroscopic characteristics of both neutral and anionic species have been ascertained. Kinetics of formation and decay, reactivity with oxygen and one-electron reduction potential values have been estimated. The semiquinone radicals have been shown to be very stable under suitable pH conditions where the equilibrium (2 semiquinone ↔ quinone + hydroquinone) lies predominantly to the left. From a measurement of the equilibrium constants at different pH, values of E 2 and E m have been calculated. (author)

  12. Study of graphene growth on copper foil by pulsed laser deposition at reduced temperature

    Science.gov (United States)

    Abd Elhamid, Abd Elhamid M.; Hafez, Mohamed A.; Aboulfotouh, Abdelnaser M.; Azzouz, Iftitan M.

    2017-01-01

    Graphene has been successfully grown on commercial copper foil at low temperature of 500 °C by pulsed laser deposition (PLD). X-ray diffraction patterns showed that films have been grown in the presence of Cu(111) and Cu(200) facets. Raman spectroscopy was utilized to study the effects of temperature, surface structure, and cooling rate on the graphene growth. Raman spectra indicate that the synthesis of graphene layers rely on the surface quality of the Cu substrate together with the proper cooling profile coupled with graphene growth temperature. PLD-grown graphene film on Cu has been verified by transmission electron microscopy. Surface mediated growth of graphene on Cu foil substrate revealed to have a favorable catalytic effect. High growth rate of graphene and less defects can be derived using fast cooling rate.

  13. Reconfigurable intelligent sensors for health monitoring: a case study of pulse oximeter sensor.

    Science.gov (United States)

    Jovanov, E; Milenkovic, A; Basham, S; Clark, D; Kelley, D

    2004-01-01

    Design of low-cost, miniature, lightweight, ultra low-power, intelligent sensors capable of customization and seamless integration into a body area network for health monitoring applications presents one of the most challenging tasks for system designers. To answer this challenge we propose a reconfigurable intelligent sensor platform featuring a low-power microcontroller, a low-power programmable logic device, a communication interface, and a signal conditioning circuit. The proposed solution promises a cost-effective, flexible platform that allows easy customization, run-time reconfiguration, and energy-efficient computation and communication. The development of a common platform for multiple physical sensors and a repository of both software procedures and soft intellectual property cores for hardware acceleration will increase reuse and alleviate costs of transition to a new generation of sensors. As a case study, we present an implementation of a reconfigurable pulse oximeter sensor.

  14. Pulsed-laser studies on the free-radical polymerization kinetics of styrene in microemulsion

    NARCIS (Netherlands)

    Manders, L.G.; Herk, van A.M.; German, A.L.; Sarnecki, J.; Schomäcker, R.; Schweer, J.

    1993-01-01

    A mean value of 339 L mol-1 s-1 was obtained for the propagation const. derived from pulsed-laser polymn. (PLP) of styrene in aq. AOT microemulsions. For accurate detns., simulations accounting for the esp. high radical concn. after the laser pulse in microemulsions were recommended. PLP with

  15. Study on characteristics of valves for pulsed gas feed into a cyclotron multicharged ion source

    International Nuclear Information System (INIS)

    Bogomolov, S.L.; Efremov, A.A.; Koval'chuk, I.M.; Kutner, V.B.; Pasyuk, A.S.

    1984-01-01

    Different valves (with rotating drum, piezoelectric and electromagnetic) for pulsed gas feed into cyclotron multicharged ion arc source are described. It is shown that piezoelectric and electromagnetic valves provide a possibility of regulating in a wide range the gas flow pulse parameters

  16. Polyphenol extraction from fresh tea leaves by pulsed electric field : a study of mechanisms

    NARCIS (Netherlands)

    Zderic, Aleksandra; Zondervan, Edwin

    2016-01-01

    The major interest in pulsed electric field treatment of biological tissues is derived from its non-thermal application: increasing cell permeability. This application has an important implication in extraction of complex organic molecules. In this work, pulsed electric field treatment is

  17. Principle study on the signal connection at transabdominal fetal pulse oximetry

    Directory of Open Access Journals (Sweden)

    Böttrich Marcel

    2016-09-01

    Full Text Available Transabdominal fetal pulse oximetry is an approach to measure oxygen saturation of the unborn child non-invasively. The principle of pulse oximetry is applied to the abdomen of a pregnant woman, such that the measured signal includes both, the maternal and the fetal pulse curve. One of the major challenges is to extract the shape of the fetal pulse curve from the mixed signal for computation of the oxygen saturation. In this paper we analyze the principle kind of connection of the fetal and maternal pulse curves in the measured signal. A time varying finite element model is used to rebuild the basic measurement environment, including a bulk tissue and two independently pulsing arteries to model the fetal and maternal blood circuit. The distribution of the light fluence rate in the model is computed by applying diffusion equation. From the detectors we extracted the time dependent fluence rate and analyzed the signal regarding its components. The frequency spectra of the signals show peaks at the fetal and maternal basic frequencies. Additional signal components are visible in the spectra, indicating multiplicative coupling of the fetal and maternal pulse curves. We conclude that the underlying signal model of algorithms for robust extraction of the shape of the fetal pulse curve, have to consider additive and multiplicative signal coupling.

  18. MR pulse sequences for selective relaxation time measurements: a phantom study

    DEFF Research Database (Denmark)

    Thomsen, C; Jensen, K E; Jensen, M

    1990-01-01

    a Siemens Magnetom wholebody magnetic resonance scanner operating at 1.5 Tesla was used. For comparison six imaging pulse sequences for relaxation time measurements were tested on the same phantom. The spectroscopic pulse sequences all had an accuracy better than 10% of the reference values....

  19. Analytical performances of laser-induced micro-plasma of Al samples with single and double ultrashort pulses in air and with Ar-jet: A comparative study

    International Nuclear Information System (INIS)

    Semerok, A.; Dutouquet, C.

    2014-01-01

    Ultrashort pulse laser microablation coupled with optical emission spectroscopy was under study to obtain several micro-LIBS analytical features (shot-to-shot reproducibility, spectral line intensity and lifetime, calibration curves, detection limits). Laser microablation of Al matrix samples with known Cu- and Mg-concentrations was performed by single and double pulses of 50 fs and 1 ps pulse duration in air and with Ar-jet. The micro-LIBS analytical features obtained under different experimental conditions were characterized and compared. The highest shot-to-shot reproducibility and gain in plasma spectral line intensity were obtained with double pulses with Ar-jet for both 50 fs and 1 ps pulse durations. The best calibration curves were obtained with 1 ps pulse duration with Ar-jet. Micro-LIBS with ultrashort double pulses may find its effective application for surface elemental microcartography. - Highlights: • Analytical performances of micro-LIBS with ultrashort double pulses were studied. • The maximal line intensity gain of 20 was obtained with double pulses and Ar-jet. • LIBS gain was obtained without additional ablation of a sample by the second pulse. • LIBS properties were almost the same for both 50 fs and 1 ps pulses. • The micro-LIBS detection limit was around 35 ppm

  20. Comparison study among conventional, tissue harmonic and pulse inversion harmonic images to evaluate pleural effusion and ascites

    International Nuclear Information System (INIS)

    Chung, Hwan Hoon; Kim, Yun Hwan; Kang, Chang Ho; Park, Bum Jin; Chung, Kyoo Byung; Suh, Won Hyuck

    2000-01-01

    To determine the most useful sonographic technique to evaluate pleural effusion and ascites by comparing conventional, tissue harmonic and pulse inversion harmonic images. 12 patients having pleural effusion and 14 patients having ascites were included in this study. 18 patients were male and 8 patients were female. Average age was 54.8 yrs (25-77). We compared images which had been taken at the same section with 3 above mentioned sonographic techniques. Evaluation was done by 3 radiologists in consensus and grades were given to 3 techniques from 1 to 3. Evaluating points were 1) normal structures that border the fluid such as liver, peritoneal lining, pleura, 2) septation in fluid, 3) debris floating in fluid, and 4) artifacts. Pulse inversion harmonic image was the best in image quality for normal structures, followed by tissue harmonic and conventional image (p<0.05). Pulse inversion harmonic image was better than conventional image to evaluate septation in fluid (p<0.05), but there were no statistically significant difference between pulse inversion and tissue harmonic images, and tissue harmonic and conventional images. Tissue harmonic image was better than pulse inversion harmonic and conventional images to evaluate debris floating in fluid (p<0.05) but there was no statistically significant difference between these two latter techniques. Artifacts were most prominent on conventional image followed by tissue harmonic and pulse inversion harmonic image (p<0.05). Pulse inversion harmonic image was the best sonographic technique to evaluate pleural effusion or ascites, However, Tissue harmonic image was the best for evaluation of debris.

  1. Comparison study among conventional, tissue harmonic and pulse inversion harmonic images to evaluate pleural effusion and ascites

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Hwan Hoon; Kim, Yun Hwan; Kang, Chang Ho; Park, Bum Jin; Chung, Kyoo Byung; Suh, Won Hyuck [Korea University College of Medicine, Seoul (Korea, Republic of)

    2000-12-15

    To determine the most useful sonographic technique to evaluate pleural effusion and ascites by comparing conventional, tissue harmonic and pulse inversion harmonic images. 12 patients having pleural effusion and 14 patients having ascites were included in this study. 18 patients were male and 8 patients were female. Average age was 54.8 yrs (25-77). We compared images which had been taken at the same section with 3 above mentioned sonographic techniques. Evaluation was done by 3 radiologists in consensus and grades were given to 3 techniques from 1 to 3. Evaluating points were 1) normal structures that border the fluid such as liver, peritoneal lining, pleura, 2) septation in fluid, 3) debris floating in fluid, and 4) artifacts. Pulse inversion harmonic image was the best in image quality for normal structures, followed by tissue harmonic and conventional image (p<0.05). Pulse inversion harmonic image was better than conventional image to evaluate septation in fluid (p<0.05), but there were no statistically significant difference between pulse inversion and tissue harmonic images, and tissue harmonic and conventional images. Tissue harmonic image was better than pulse inversion harmonic and conventional images to evaluate debris floating in fluid (p<0.05) but there was no statistically significant difference between these two latter techniques. Artifacts were most prominent on conventional image followed by tissue harmonic and pulse inversion harmonic image (p<0.05). Pulse inversion harmonic image was the best sonographic technique to evaluate pleural effusion or ascites, However, Tissue harmonic image was the best for evaluation of debris.

  2. An automated pulse labelling method for structure-activity relationship studies with antibacterial oxazolidinones.

    Science.gov (United States)

    Eustice, D C; Brittelli, D R; Feldman, P A; Brown, L J; Borkowski, J J; Slee, A M

    1990-01-01

    The 3-aryl-2-oxooxazolidinones are a new class of synthetic antibacterial agents that potently inhibit protein synthesis. An automated pulse labelling method with [3H]-lysine was developed with Bacillus subtilis to obtain additional quantitative activity data for structure-activity relationship studies with the oxazolidinones. Inhibition constants were calculated after a Logit fit of the data into the formula: % of control = 100/(1 + e[-B(X - A)]), where B is the slope of the model, X is the natural log of the inhibitor concentration and A is the natural log of the inhibitor concentration required to inhibit protein synthesis by 50% (ln IC50). When substituents at the 5-methyl position of the heterocyclic ring (B-substituent) were NHCOCH3, OH or Cl, the correlation coefficient was 0.87 between the MIC and IC50 values (for all compounds with MICs less than or equal to 16 micrograms/ml). The D-isomers of DuP 721 (A-substituent = CH3CO) and DuP 105 (A-substituent = CH3SO) gave MICs of 128 micrograms/ml and IC50s of greater than or equal to 50 micrograms/ml for protein synthesis, showing that only the L-isomers were active. By MIC testing, oxazolidinones with the B-substituent of NHCOCH3 and the A-substituent of CH3CO, NO2, CH3S, CH3SO2 or (CH3)2CH had comparable antibacterial potency; however, pulse labelling analysis showed that compounds with an A-substituent of CH3CO or NO2 were more potent inhibitors of protein synthesis.

  3. Studies of the confinement at laser-induced backside dry etching using infrared nanosecond laser pulses

    Science.gov (United States)

    Ehrhardt, M.; Lorenz, P.; Bayer, L.; Han, B.; Zimmer, K.

    2018-01-01

    In the present study, laser-induced backside etching of SiO2 at an interface to an organic material using laser pulses with a wavelength of λ = 1064 nm and a pulse length of τ = 7 ns have been performed in order to investigate selected processes involved in etching of the SiO2 at confined ablation conditions with wavelengths well below the band gap of SiO2. Therefore, in between the utilized metallic absorber layer and the SiO2 surface, a polymer interlayer with a thickness between 20 nm to 150 nm was placed with the aim, to separate the laser absorption process in the metallic absorber layer from the etching process of the SiO2 surface due to the provided organic interlayer. The influence of the confinement of the backside etching process was analyzed by the deposition of different thick polymer layers on top of the metallic absorber layer. In particular, it was found that the SiO2 etching depth decreases with higher polymer interlayer thickness. However, the etching depth increases with increasing the confinement layer thickness. SEM images of the laser processed areas show that the absorber and confinement layers are ruptured from the sample surface without showing melting, and suggesting a lift off process of these films. The driving force for the layers lift off and the etching of the SiO2 is probably the generated laser-induce plasma from the confined ablation that provides the pressure for lift off, the high temperatures and reactive organic species that can chemically attack the SiO2 surface at these conditions.

  4. Analytical and Numerical Studies of the Complex Interaction of a Fast Ion Beam Pulse with a Background Plasma

    International Nuclear Information System (INIS)

    Kaganovich, Igor D.; Startsev, Edward A.; Davidson, Ronald C.

    2003-01-01

    Plasma neutralization of an intense ion beam pulse is of interest for many applications, including plasma lenses, heavy ion fusion, high energy physics, etc. Comprehensive analytical, numerical, and experimental studies are underway to investigate the complex interaction of a fast ion beam with a background plasma. The positively charged ion beam attracts plasma electrons, and as a result the plasma electrons have a tendency to neutralize the beam charge and current. A suite of particle-in-cell codes has been developed to study the propagation of an ion beam pulse through the background plasma. For quasi-steady-state propagation of the ion beam pulse, an analytical theory has been developed using the assumption of long charge bunches and conservation of generalized vorticity. The analytical results agree well with the results of the numerical simulations. The visualization of the data obtained in the numerical simulations shows complex collective phenomena during beam entry into and ex it from the plasma

  5. The study of Zn–Co alloy coatings electrochemically deposited by pulse current

    Directory of Open Access Journals (Sweden)

    Tomić Milorad V.

    2012-01-01

    Full Text Available The electrochemical deposition by pulse current of Zn-Co alloy coatings on steel was examined, with the aim to find out whether pulse plating could produce alloys that could offer a better corrosion protection. The influence of on-time and the average current density on the cathodic current efficiency, coating morphology, surface roughness and corrosion stability in 3% NaCl was examined. At the same Ton/Toff ratio the current efficiency was insignificantly smaller for deposition at higher average current density. It was shown that, depending on the on-time, pulse plating could produce more homogenous alloy coatings with finer morphology, as compared to deposits obtained by direct current. The surface roughness was the greatest for Zn-Co alloy coatings deposited with direct current, as compared with alloy coatings deposited with pulse current, for both examined average current densities. It was also shown that Zn-Co alloy coatings deposited by pulse current could increase the corrosion stability of Zn-Co alloy coatings on steel. Namely, alloy coatings deposited with pulse current showed higher corrosion stability, as compared with alloy coatings deposited with direct current, for almost all examined cathodic times, Ton. Alloy coatings deposited at higher average current density showed greater corrosion stability as compared with coatings deposited by pulse current at smaller average current density. It was shown that deposits obtained with pulse current and cathodic time of 10 ms had the poorest corrosion stability, for both investigated average deposition current density. Among all investigated alloy coatings the highest corrosion stability was obtained for Zn-Co alloy coatings deposited with pulsed current at higher average current density (jav = 4 A dm-2.

  6. Structural, morphological and Raman studies of pulse electrosynthesised indium antimonide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Joginder, E-mail: joginderchauhan82@gmail.com; Chandel, Tarun; Rajaram, P. [School of Studies in Physics, Jiwaji University, Gwalior (MP), India-474011 (India)

    2015-08-28

    InSb films deposited on fluorine doped tin oxide (FTO) substrates by a pulse elctrodeposition technique. The deposition was carried out at an applied potential −1.3V versus Ag/AgCl electrode. Structural, morphological and optical studies were performed on the electrodeposited InSb. X-ray diffraction (XRD) studies show that the deposited InSb films are polycrystalline in nature having the zinc blend structure. The crystallite size (D), dislocation density (δ) and strain (ε) were calculated using XRD results. The EDAX analysis shows that chemical composition of In{sup 3+} and Sb{sup 3+} ions is close to the required stoichiometry. The surface morphology of the deposited films was examined using scanning electron microscopy (SEM). SEM studies reveal that the surface of the films is uniformly covered with submicron sized spherical particles. However, the crystallite size determined by the Scherrer method shows a size close to 30 nm. Surface morphology studies of the InSb films were also performed using atomic force microscopy (AFM). The average surface roughness as measured by AFM is around 40 nm. Hot probe studies show that all the electrodeposited thin films have n type conductivity and the thickness of the films is calculated using electrochemical formula.

  7. Study of the fast inversion recovery pulse sequence. With reference to fast fluid attenuated inversion recovery and fast short TI inversion recovery pulse sequence

    International Nuclear Information System (INIS)

    Tsuchihashi, Toshio; Maki, Toshio; Suzuki, Takeshi

    1997-01-01

    The fast inversion recovery (fast IR) pulse sequence was evaluated. We compared the fast fluid attenuated inversion recovery (fast FLAIR) pulse sequence in which inversion time (TI) was established as equal to the water null point for the purpose of the water-suppressed T 2 -weighted image, with the fast short TI inversion recovery (fast STIR) pulse sequence in which TI was established as equal to the fat null point for purpose of fat suppression. In the fast FLAIR pulse sequence, the water null point was increased by making TR longer. In the FLAIR pulse sequence, the longitudinal magnetization contrast is determined by TI. If TI is increased, T 2 -weighted contrast improves in the same way as increasing TR for the SE pulse sequence. Therefore, images should be taken with long TR and long TI, which are longer than TR and longer than the water null point. On the other hand, the fat null point is not affected by TR in the fast STIR pulse sequence. However, effective TE was affected by variation of the null point. This increased in proportion to the increase in effective TE. Our evaluation indicated that the fast STIR pulse sequence can control the extensive signals from fat in a short time. (author)

  8. Efficacy and cognitive side effects after brief pulse and ultrabrief pulse right unilateral electroconvulsive therapy for major depression: a randomized, double-blind, controlled study

    NARCIS (Netherlands)

    Spaans, H.P.; Verwijk, E.; Comijs, H.C.; Kok, R.M.; Sienaert, P.; Bouckaert, F.; Fannes, K.; Vandepoel, K.; Scherder, E.J.A.; Stek, M.L.; Kho, K.H.

    2013-01-01

    Objective: To compare the efficacy and cognitive side effects of high-dose unilateral brief pulse electroconvulsive therapy (ECT) with those of high-dose unilateral ultrabrief pulse ECT in the treatment of major depression. Method: From April 2007 until March 2011, we conducted a prospective,

  9. Magnetic Resonance Studies of Proton Loss from Carotenoid Radical Cations

    Energy Technology Data Exchange (ETDEWEB)

    Kispert, Lowell D [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Focsan, A Ligia [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Konovalova, Tatyana A [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lawrence, Jesse [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Bowman, Michael K [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Dixon, David A [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Molnar, Peter [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Deli, Jozsef [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2007-06-11

    Carotenoids, intrinsic components of reaction centers and pigment-protein complexes in photosynthetic membranes, play a photoprotective role and serve as a secondary electron donor. Before optimum use of carotenoids can be made in artificial photosynthetic systems, their robust nature in living materials requires extensive characterization of their electron transfer, radical trapping ability, stability, structure in and on various hosts, and photochemical behavior. Pulsed ENDOR and 2D-HYSCORE studies combined with DFT calculations reveal that photo-oxidation of natural zeaxanthin (I) and violaxanthin (II) on silica-alumina produces not only the carotenoid radical cations (Car•+) but also neutral radicals (#Car•) by proton loss from the methyl groups at positions 5 or 5', and possibly 9 or 9' and 13 or 13'. Notably, the proton loss favored in I at the 5 position by DFT calculations, is unfavorable in II due to the epoxide at the 5, 6 position. DFT calculations predict the isotropic methyl proton couplings of 8-10 MHz for Car•+ which agree with the ENDOR for carotenoid α-conjugated radical cations. Large α-proton hyperfine coupling constants (>10 MHz) determined from HYSCORE are assigned from the DFT calculations to neutral carotenoid radicals. Proton loss upon photolysis was also examined as a function of carotenoid polarity [Lycopene (III) versus 8'-apo-β-caroten-8'-al (IV)]; hydrogen bonding [Lutein (V) versus III]; host [silica-alumina versus MCM-41 molecular sieve]; and substituted metal in MCM-41. Loss of H+ from the 5(5'), 9(9') or 13(13') methyl positions has importance in photoprotection. Photoprotection involves nonphotochemical quenching (NPQ) in which 1Ch1* decays via energy transfer to the carotenoid which returns to the ground state by thermal dissipation; or via electron transfer to form a charge transfer state (I •+…Chl•-), lower in energy than 1Chl*. Formation of I •+ results in bond

  10. Magnetic Resonance Studies of Proton Loss from Carotenoid Radical Cations

    International Nuclear Information System (INIS)

    Kispert, Lowell D.; Focsan, A. Ligia; Konovalova, Tatyana A.; Lawrence, Jesse; Bowman, Michael K.; Dixon, David A.; Molnar, Peter; Deli, Jozsef

    2007-01-01

    Carotenoids, intrinsic components of reaction centers and pigment-protein complexes in photosynthetic membranes, play a photoprotective role and serve as a secondary electron donor. Before optimum use of carotenoids can be made in artificial photosynthetic systems, their robust nature in living materials requires extensive characterization of their electron transfer, radical trapping ability, stability, structure in and on various hosts, and photochemical behavior. Pulsed ENDOR and 2D-HYSCORE studies combined with DFT calculations reveal that photo-oxidation of natural zeaxanthin (I) and violaxanthin (II) on silica-alumina produces not only the carotenoid radical cations (Car ·+ ) but also neutral radicals ((number s ign)Car · ) by proton loss from the methyl groups at positions 5 or 5(prime), and possibly 9 or 9(prime) and 13 or 13(prime). Notably, the proton loss favored in I at the 5 position by DFT calculations, is unfavorable in II due to the epoxide at the 5, 6 position. DFT calculations predict the isotropic methyl proton couplings of 8-10 MHz for Car # center d ot# + which agree with the ENDOR for carotenoid π-conjugated radical cations. Large α-proton hyperfine coupling constants (>10 MHz) determined from HYSCORE are assigned from the DFT calculations to neutral carotenoid radicals. Proton loss upon photolysis was also examined as a function of carotenoid polarity (Lycopene (III) versus 8(prime)-apo-β-caroten-8(prime)-al (IV)); hydrogen bonding (Lutein (V) versus III); host (silica-alumina versus MCM-41 molecular sieve); and substituted metal in MCM-41. Loss of H + from the 5(5(prime)), 9(9(prime)) or 13(13(prime)) methyl positions has importance in photoprotection. Photoprotection involves nonphotochemical quenching (NPQ) in which 1 Ch1* decays via energy transfer to the carotenoid which returns to the ground state by thermal dissipation; or via electron transfer to form a charge transfer state (I # center d ot# + ...Chl # center d ot# - ), lower in

  11. Study and realisation of a programmable generator of pulse sequences, for nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Lambert, Daniel

    1974-01-01

    After having recalled the operation of pulse-based nuclear magnetic resonance and the use of pulse sequences in NMR-based measurements, and outlined the need for a pulse sequence generator, the author reports the design and realisation of such a device. He describes its general organisation with its base sequence, base clock, sequence start, duration, displays, data transfers, data processing, and signal distribution. He presents the chosen technology (ECL logics), the sequence base set, time bases, multiplexers, comparison sets, the distribution set, the sequence programming, the sampling and output set. He reports tests and the use of the so-designed generator [fr

  12. Study of graphitic microstructure formation in diamond bulk by pulsed Bessel beam laser writing

    Science.gov (United States)

    Kumar, S.; Sotillo, B.; Chiappini, A.; Ramponi, R.; Di Trapani, P.; Eaton, S. M.; Jedrkiewicz, O.

    2017-11-01

    The advantages of using Bessel beams for the generation of graphitic structures in diamond bulk are presented. We show that by irradiating the sample with a pulsed Bessel beam whose non-diffracting zone is of the same order of the sample thickness, it is possible to produce without any sample translation straight graphitic through-microstructures, whose size depends on the input pulse energy. The microstructure growth is investigated as a function of the number of irradiating pulses, and the femtosecond and picosecond regimes are contrasted.

  13. Pulse radiolysis study of monomer and dimer cations of styrene, 1-methylstyrene and 1,1'-diphenylethylene

    International Nuclear Information System (INIS)

    Mehnert, R.; Helmstreit, W.; Boes, J.; Brede, O.

    1977-01-01

    In pulse-irradiated solutions of styrene, 1-methylstyrene and 1,1'-diphenylethylene, the decay kinetics of the olefin monomer cations and the formation kinetics of the corresponding dimer cations have been studied at room temperature. The solutions were irradiated with 15-nsec 15-ampere pulses of 1-MeV electrons from an Elit-type accelerator. The total dose per pulse was approximately 10 krad. The monomer cations were generated with rate constants of about 10 11 M -1 sec -1 . From the time decay of the monomer light absorption and the growth in time of the dimer absorption rate constants for the dimer formation between 0.8x10 10 and 1.2x10 10 M -1 sec -1 have been determined. (T.I.)

  14. Pulsed activation analyses of the ITER blanket design options considered in the blanket trade-off study

    International Nuclear Information System (INIS)

    Wang, Q.; Henderson, D.L.

    1995-01-01

    Pulsed activation calculations have been performed on two blanket options considered as part of the ITER home team blanket trade-off study. The objective was to compare the activity, afterheat and waste disposal rating (WDR) results of a composite blanket-shield design for the continuous operation approximation to a pulsed operation case to determine whether the differences are at most the duty factor as predicted by the two nuclide chain model. Up to a cooling period of 100 years, the pulsed activity and afterheat values were below the continuous oepration results and well within (except for one afterheat value) the maximum deviation predicted by the two nuclide chain model. No differences in the WDR values were noted as they are, to a large extent, based on long-lived nuclides which are insensitive to short-term changes in the operation history. (orig.)

  15. Experimental and theoretical studies of the physical processes occurring in thin plane targets irradiated by intense X-ray pulses

    International Nuclear Information System (INIS)

    Bugrov, A. E.; Burdonskii, I. N.; Gavrilov, V. V.; Gol'tsov, A. Yu.; Grabovskii, E. V.; Efremov, V. P.; Zhuzhukalo, E. V.; Zurin, M. V.; Koval'skii, N. G.; Kondrashov, V. N.; Oleinik, G. M.; Potapenko, A. I.; Samokhin, A. A.; Smirnov, V. P.; Fortov, V. E.; Frolov, I. N.

    2007-01-01

    Results are presented from experimental and theoretical studies of the interaction of intense X-ray pulses with different types of plane targets, including low-density (∼10 mg/cm 3 ) ones, in the Angara-5-1 facility. It is found experimentally that a dense low-temperature plasma forms on the target surface before the arrival of the main heating X-ray pulse. It is demonstrated that the contrast of the X-ray pulse can be increased by placing a thin organic film between the target and the discharge gap. The expansion velocity of the plasma created on the target surface irradiated by Z-pinch-produced X rays was found to be (3-4) x 10 6 cm/s. A comparison between the simulation and experimental results confirms the validity of the physical-mathematical model used

  16. Urinary 1H Nuclear Magnetic Resonance Metabolomic Fingerprinting Reveals Biomarkers of Pulse Consumption Related to Energy-Metabolism Modulation in a Subcohort from the PREDIMED study.

    Science.gov (United States)

    Madrid-Gambin, Francisco; Llorach, Rafael; Vázquez-Fresno, Rosa; Urpi-Sarda, Mireia; Almanza-Aguilera, Enrique; Garcia-Aloy, Mar; Estruch, Ramon; Corella, Dolores; Andres-Lacueva, Cristina

    2017-04-07

    Little is known about the metabolome fingerprint of pulse consumption. The study of robust and accurate biomarkers for pulse dietary assessment has great value for nutritional epidemiology regarding health benefits and their mechanisms. To characterize the fingerprinting of dietary pulses (chickpeas, lentils, and beans), spot urine samples from a subcohort from the PREDIMED study were stratified using a validated food frequency questionnaire. Urine samples of nonpulse consumers (≤4 g/day of pulse intake) and habitual pulse consumers (≥25 g/day of pulse intake) were analyzed using a 1 H nuclear magnetic resonance (NMR) metabolomics approach combined with multi- and univariate data analysis. Pulse consumption showed differences through 16 metabolites coming from (i) choline metabolism, (ii) protein-related compounds, and (iii) energy metabolism (including lower urinary glucose). Stepwise logistic regression analysis was applied to design a combined model of pulse exposure, which resulted in glutamine, dimethylamine, and 3-methylhistidine. This model was evaluated by a receiver operating characteristic curve (AUC > 90% in both training and validation sets). The application of NMR-based metabolomics to reported pulse exposure highlighted new candidates for biomarkers of pulse consumption and the impact on energy metabolism, generating new hypotheses on energy modulation. Further intervention studies will confirm these findings.

  17. Pulsed Electrical Spin Injection into InGaAs Quantum Dots: Studies of the Electroluminescence Polarization Dynamics

    International Nuclear Information System (INIS)

    Asshoff, P.; Loeffler, W.; Fluegge, H.; Zimmer, J.; Mueller, J.; Westenfelder, B.; Hu, D. Z.; Schaadt, D. M.; Kalt, H.; Hetterich, M.

    2010-01-01

    We present time-resolved studies of the spin polarization dynamics during and after initialization through pulsed electrical spin injection into InGaAs quantum dots embedded in a p-i-n-type spin-injection light-emitting diode. Experiments are performed with pulse widths in the nanosecond range and a time-resolved single photon counting setup is used to detect the subsequent electroluminescence. We find evidence that the achieved spin polarization shows an unexpected temporal behavior, attributed mainly to many-carrier and non-equilibrium effects in the device.

  18. Development and application of resistive pulse spectroscopy: studies on the size, form and deformability of red blood cells

    Energy Technology Data Exchange (ETDEWEB)

    Yee, J.P.

    1979-01-01

    The following studies were conducted using the resistive pulse spectroscopy (RPS) technique: cumulative spectra and individual pulse forms for rigid latex polymer spheres; acquisition and analysis of RPS spectral data by means of special computer program; interaction of red blood cells with glutaraldehyde; membrane properties of erythrocytes undergoing abrupt osmotic hemolysis; reversible effects of the binding of chlorpromazine HCl at the red cell membrane surface; effects of high cholesterol diet on erythrocytes of guinea pigs; and multi-population analysis for a mixture of fetal and maternal red cells. (HLW)

  19. Numerical and experimental studies of mechanisms underlying the effect of pulsed broadband terahertz radiation on nerve cells

    Energy Technology Data Exchange (ETDEWEB)

    Duka, M V; Dvoretskaya, L N; Babelkin, N S; Khodzitskii, M K; Chivilikhin, S A; Smolyanskaya, O A [St. Petersburg National Research University of Information Technologies, Mechanics and Optics, St. Petersburg (Russian Federation)

    2014-08-31

    We have studied the mechanisms underlying the effect of pulsed broadband terahertz radiation on the growth of neurites of sensory ganglia using a comparative analysis of measured reflection spectra of ganglion neurites (in the frequency range 0.1 – 2.0 THz) and spectra obtained by numerical simulation with CST Microwave Studio. The observed changes are shown to be mainly due to pulse energy absorption in the ganglion neurites. Of particular interest are the observed single resonance frequencies related to resonance size effects, which can be used to irradiate ganglia in order to activate their growth. (laser biophotonics)

  20. Study on Writing Transmission Metal Grating with Pulse Shaping of Femtosecond Laser

    International Nuclear Information System (INIS)

    Ni, X C; Sun, Q; Wang, Ch Y; Yang, L; Wu, Y Z; Jia, W; Chai, L

    2006-01-01

    Pulse shaping in femtosecond(fs) laser micromachining is different from that of traditional laser, whose main purpose is to reduce focal scale size, wipe off fluorescence around laser beam, decrease pulse distortion, and fabricate all kinds of figures. To describe the spatial form of laser pulse around focal scale, the synchronous moving of focal objective and accepting material is presented. When a pinhole mask is placed in front of focal objective, the changing trend of laser spatial form around focal point with the laser beam diameter will be obtained by the diameter changing of the hole mask. Experimental results show that the diameter of laser pulse around focal point trends smoothly when the pinhole diameter is modulated to smaller, even the position of beam waist is changed. These phenomena can be explained by optical imaging theory. Finally, the transmission metal grating is written successfully with a selected parameter

  1. Pulse radiolysis studies of fast reactions in molecular systems. Progress report, November 1976--October 1977

    International Nuclear Information System (INIS)

    Dorfman, L.M.

    1977-01-01

    Results from research in the following two areas are given: formation, properties, and reactivity of molecular ionic species in irradiated liquid systems; and pulse radiolysis of elementary reactions in protein function

  2. Optimal pulse sequence for ferumoxides-enhanced MR imaging used in the detection of hepatocellular carcinoma: a comparative study using seven pulse sequences

    International Nuclear Information System (INIS)

    Kim, Seung Hoon; Choi, Dongil; Lim, Jae Hoon; Lee, Won Jae; Jang, Hyun Jung; Lim, Kyo Keun; Lee, Soon Jin; Cho, Jae Min; Kim, Seung Kwon; Kim, Gab Chul

    2002-01-01

    To identify the optimal pulse sequence for ferumoxides-enhanced magnetic resonance (MR) imaging in the detection of hepatocelluar carcinomas (HCCs). Sixteen patients with 25 HCCs underwent MR imaging following intravenous infusion of ferumoxides. All MR studies were performed on a 1.5-T MR system, using a phased-array coil. Ferumoxides (Feridex IV) at a dose of 15 μmol/Kg was slowly infused intravenously, and axial images of seven sequences were obtained 30 minutes after the end of infusion. The MR protocol included fast spin-echo (FSE) with two echo times (TR3333-8571/TE18 and 90-117), singleshot FSE (SSFSE) with two echo times (TR∞/TE39 and 98), T2-weighted gradient-recalled acquisition in the steady state (GRASS) (TR216/TE20), T2-weighted fast multiplanar GRASS (FMPGR) (TR130/TE8.4-9.5), and T2-weighted fast multiplanar spoiled GRASS (FMPSPGR) (TR130/TE8.4-9.5). Contrast-to-noise ratios (CNRs) of HCCs determined during the imaging sequences formed the basis of quantitative analysis, and images were qualitatively assessed in terms of lesion conspicuity and image artifacts. The diagnostic accuracy of all sequences was assessed using receiver operating characteristic (ROC) analysis. Quantitative analysis revealed that the CNRs of T2-weighted FMPGR and T2-weighted FMPSPGR were significantly higher than those of the other sequences, while qualitative analysis showed that image artifacts were prominent at T2-weighted GRASS imaging. Lesion conspicuity was statistically significantly less clear at SSFSE imaging. In term of lesion detection, T-weighted FMPGR, T2- weighted FMPSPGR, and proton density FSE imaging were statistically superior to the others. T2-weighted FMPGR, T2- weighted FMPSPGR, and proton density FSE appear to be the optimal pulse sequences for ferumoxidesenhanced MR imaging in the detection of HCCs

  3. Experimental studies of thorium ion implantation from pulse laser plasma into thin silicon oxide layers

    Science.gov (United States)

    Borisyuk, P. V.; Chubunova, E. V.; Lebedinskii, Yu Yu; Tkalya, E. V.; Vasilyev, O. S.; Yakovlev, V. P.; Strugovshchikov, E.; Mamedov, D.; Pishtshev, A.; Karazhanov, S. Zh

    2018-05-01

    We report the results of experimental studies related to implantation of thorium ions into thin silicon dioxide by pulsed plasma flux expansion. Thorium ions were generated by laser ablation from a metal target, and the ionic component of the laser plasma was accelerated in an electric field created by the potential difference (5, 10 and 15 kV) between the ablated target and a SiO2/Si (0 0 1) sample. The laser ablation system installed inside the vacuum chamber of the electron spectrometer was equipped with a YAG:Nd3  +  laser having a pulse energy of 100 mJ and time duration of 15 ns in the Q-switched regime. The depth profile of thorium atoms implanted into the 10 nm thick subsurface areas together with their chemical state as well as the band gap of the modified silicon oxide at different conditions of implantation processes were studied by means of x-ray photoelectron spectroscopy and reflected electron energy loss spectroscopy methods. Analysis of the chemical composition showed that the modified silicon oxide film contains complex thorium silicates. Depending on the local concentration of thorium atoms, the experimentally established band gaps were located in the range 6.0–9.0 eV. Theoretical studies of the optical properties of the SiO2 and ThO2 crystalline systems were performed by ab initio calculations within hybrid functional. The optical properties of the SiO2/ThO2 composite were interpreted on the basis of the Bruggeman effective medium approximation. A quantitative assessment of the yield of isomeric nuclei in ‘hot’ laser plasma at the early stages of expansion was performed. The estimates made with experimental results demonstrated that the laser implantation of thorium ions into the SiO2 matrix can be useful for further research of low-lying isomeric transitions in a 229Th isotope with energy of 7.8 +/- 0.5 eV.

  4. Pulsed EPR studies of small reactive radicals produced by ionizing radiation

    International Nuclear Information System (INIS)

    Lawler, R.G.

    1985-01-01

    For several years we have participated in a collaborative research effort to apply the pulsed EPR-pulse radiolysis technique to several problems associated with the dynamics of small reactive radicals formed during radiolysis of aqueous solutions using 3 MeV electrons from a Van de Graaff accelerator. We will discuss experimental techniques and applications arising from this work, with particular emphasis on problems requiring high initial radical concentrations and EPR time resolution of one microsecond or better. 2 figs., 2 tabs

  5. Study of hydrodynamic and mass transfer parameters in pulsed sieve-plate columns

    International Nuclear Information System (INIS)

    Safdari, J.

    2001-01-01

    One of the most important liquid-liquid extractor in industry is pulsed column. The pulsed columns are generally classified into the following categories: 1-Pulsed perforated-plate column. 2- Pulsed packed column. The pulsed plate column is differential contactor with the application of mechanical energy and is used for a diverse range of processes. Probably its best known application has been in the nuclear fuel industry. The pulsed plate column consists of a cylindrical shell with settling zones at the top and the bottom of the column. The liquids are fed continuously to the column (flowing counter-currently) and are removed continuously from opposite ends of the column. In this work using a pilot pulsed plate column and two different chemical systems (toluene/acetone/water and n-butyl acetate/acetone/water) various experiments are carried out. In each experiment direction of mass transfer is from organic phase (dispersed phase) into aqueous phase (continuous phase) and the continuous phase is water. The main objects of this thesis are as follow: a- Investigation of effect of operating parameters on dispersed phase hold up, volumetric overall mass transfer coefficients based on dispersed and continuous phase, extraction efficiency, pressure drop of column and flooding velocities (maximum column capacities). Obtained results in this part show that if the calorimetric flow rate of aqueous phase or pulsation intensity increase, hold up, volumetric overall mass transfer coefficients based on both two phases and extraction efficiency will increase and flooding velocities will decrease. Also results show that if volumetric flow rate of organic phase increase, hold up, volumetric mass transfer coefficients based on both two phases and pressure drop will increase and extraction efficiency and flooding velocities will decrease. b- Investigation of effect of internal circulation inside drops in designing pulsed perforated-plate column

  6. Comparative study on preliminary breakdown pulse trains observed in Johor, Malaysia and Florida, USA

    Science.gov (United States)

    Baharudin, Z. A.; Ahmad, Noor Azlinda; Fernando, M.; Cooray, V.; Mäkelä, J. S.

    2012-11-01

    In this paper, the preliminary breakdown (PB) pulse train preceding the negative first return stroke (RS) is recorded using a broad band antenna system. These analyses were carried out in Johor Bahru, Malaysia and Florida, United States. This is a novel initiative at examining and identifying the characteristics of the PB pulse trains in the negative cloud-to-ground flashes observed in Malaysia. The arithmetic mean of the total pulse train duration is 12.3 ms and the weighted arithmetic mean of the pulse durations and interpulse intervals are 11 μs and 152 μs, respectively. The arithmetic mean ratio between the maximum peak amplitude of the PB pulse and the peak RS electric field was 27.8%, and the corresponding value in Florida was 29.4%. The arithmetic mean of the time duration between the most active part of the pulse train, and the RS was 57.6 ms in Malaysia and 22 ms in Florida. A qualitative comparison of our results with those obtained earlier in Sri Lanka, Sweden and Finland supports the hypothesis that the PBP/RS ratio is higher in the northern regions compared to the tropical regions.

  7. Study on pulsed-operation of the drift tube quadrupole magnets

    International Nuclear Information System (INIS)

    Mutou, M.

    1982-01-01

    The heavy ion linac for NUMATRON project is designed not only as a injector for a synchrotron but also as a supplier of heavy ion beams for experiments with linac beam. In one repetition cycle of the synchrotron (1sec), the linac injects nearly 25 beam pulses with pulse width of 300 μsec and pulse interval of 30 msec. And the ion species can be varied every repetition. On the other hand, when it is off duty of injection to the synchrotron, the linac accelerates the beams that are directly used for the experiments. Also in this case, the ion species should be varied according to the requests of the experiments, for instance every 1 sec. Therefore, the quadrupole magnets installed in the drift tubes of the linac must be excited with pulse mode. The power supply of the quadrupole magnets will consists of two parts, namely pulse-excitation and dc-excitation power sources. The report describes the posibilities on the pulse-operation of the quadrupole magnets with the field gradient of asymptotically equals 10 KG/cm, and the analysis of the power supply of the quadrupole magnets. (author)

  8. Numerical study on transverse asymmetry in the temperature profile of a regenerator in a pulse tube cooler

    DEFF Research Database (Denmark)

    Andersen, Stig Kildegård; Dietrich, M.; Carlsen, Henrik

    2007-01-01

    Transverse asymmetry in the temperature profile of the regenerator in a Stirling-type pulse tube cooler as observed in experiments was analysed in a numerical study. The asymmetry was reproduced using a one-dimensional model of the cooler where the regenerator was modelled using two identical...

  9. Time-resolved study of a pulsed dc discharge using quantum cascade laser absorption spectroscopy : NO and gas temperature kinetics

    NARCIS (Netherlands)

    Welzel, S.; Gatilova, L.; Röpcke, J.; Rousseau, A.

    2007-01-01

    In a pulsed dc discharge of an Ar–N2 mixture containing 0.91% of NO the kinetics of the destruction of NO has been studied under static and flowing conditions, i.e. in a closed and open discharge tube (p = 266 Pa). For this purpose quantum cascade laser absorption spectroscopy (QCLAS) in the

  10. NO kinetics in pulsed low-pressure nitrogen plasmas studied by time resolved quantum cascade laser absorption spectroscopy

    NARCIS (Netherlands)

    Welzel, S.; Guaitella, O.; Lazzaroni, C.; Pintassilgo, C.; Rousseau, A.; Röpcke, J.

    2011-01-01

    Time-resolved quantum cascade laser absorption spectroscopy at 1897 cm-1 (5.27 µm) has been applied to study the NO(X) kinetics on the micro- and millisecond time scale in pulsed low-pressure N2/NO dc discharges. Experiments have been performed under flowing and static gas conditions to infer the

  11. Pulse and gamma radiolytic studies of Ag, Cd and mixed clusters in aqueous solutions of carboxymethyl cellulose and gelatin

    International Nuclear Information System (INIS)

    Kapoor, Sudhir; Gopinathan, C.

    1996-01-01

    Pulse and gamma radiolytic studies in aqueous solutions of Ag, Cd and mixed clusters were carried out in carboxymethylcellulose (CMC) or gelatin. The reaction rate of e aq - with Ag + is lower in the presence of CMC or gelatin and oligomeric clusters of silver, Cd and mixed clusters get stabilized in their presence. (author). 2 refs., 2 figs

  12. Noninvasive pulse pressure variation and stroke volume variation to predict fluid responsiveness at multiple thresholds : a prospective observational study

    NARCIS (Netherlands)

    Vos, Jaap Jan; Poterman, Marieke; Papineau Salm, Pieternel; Van Amsterdam, Kai; Struys, Michel M. R. F.; Scheeren, Thomas W. L.; Kalmar, Alain F.

    2015-01-01

    Pulse pressure variation (PPV) and stroke volume variation (SVV) are dynamic preload variables that can be measured noninvasively to assess fluid responsiveness (FR) in anesthetized patients with mechanical ventilation. Few studies have examined the effectiveness of predicting FR according to the

  13. Biosynthesis of intestinal microvillar proteins. Pulse-chase labelling studies on maltase-glucoamylase, aminopeptidase A and dipeptidyl peptidase IV

    DEFF Research Database (Denmark)

    Danielsen, E M; Sjöström, H; Norén, Ove

    1983-01-01

    The biogenesis of three intestinal microvillar enzymes, maltase-glucoamylase (EC 3.2.1.20), aminopeptidase A (aspartate aminopeptidase, EC 3.4.11.7) and dipeptidyl peptidase IV (EC 3.4.14.5), was studied by pulse-chase labelling of pig small-intestinal explants kept in organ culture. The earliest...

  14. Pulsed lasers versus continuous light sources in capillary electrophoresis and fluorescence detection studies: Photodegradation pathways and models

    International Nuclear Information System (INIS)

    Boutonnet, Audrey; Morin, Arnaud; Petit, Pierre; Vicendo, Patricia; Poinsot, Véréna; Couderc, François

    2016-01-01

    Pulsed lasers are widely used in capillary electrophoresis (CE) studies to provide laser induced fluorescence (LIF) detection. Unfortunately pulsed lasers do not give linear calibration curves over a wide range of concentrations. While this does not prevent their use in CE/LIF studies, the non-linear behavior must be understood. Using 7-hydroxycoumarin (7-HC) (10–5000 nM), Tamra (10–5000 nM) and tryptophan (1–200 μM) as dyes, we observe that continuous lasers and LEDs result in linear calibration curves, while pulsed lasers give polynomial ones. The effect is seen with both visible light (530 nm) and with UV light (355 nm, 266 nm). In this work we point out the formation of byproducts induced by pulsed laser upon irradiation of 7-HC. Their separation by CE using two Zeta LIF detectors clearly shows that this process is related to the first laser detection. All of these photodegradation products can be identified by an ESI-/MS investigation and correspond to at least two 7HC dimers. By using the photodegradation model proposed by Heywood and Farnsworth (2010) and by taking into account the 7-HC results and the fact that in our system we do not have a constant concentration of fluorophore, it is possible to propose a new photochemical model of fluorescence in LIF detection. The model, like the experiment, shows that it is difficult to obtain linear quantitation curves with pulsed lasers while UV-LEDs used in continuous mode have this advantage. They are a good alternative to UV pulsed lasers. An application involving the separation and linear quantification of oligosaccharides labeled with 2-aminobezoic acid is presented using HILIC and LED (365 nm) induced fluorescence. - Highlights: • No linear calibration curves are obtained in CE/Pulsed-LIF detection. • Photodegradation and photodimerisation are responsible of this non linearity. • A mathematical model of this phenomenon is presented. • 7 hydroxycoumarin in CE/LIF is used to verify the

  15. Fast reactions of organic anion radicals with organic halides in hexamethylphosphoric triamide studied by pulse radiolysis

    International Nuclear Information System (INIS)

    Honda, Eiji; Tokuda, Masao; Yoshida, Hiroshi; Ogasawara, Masaaki

    1987-01-01

    Fast reactions of diethyl fumarate anion radical (DEF - ) and fluorenone anion radical (Fl - ) with various organic halides (RX) in hexamethylphosphoric triamide have been studied by means of ns pulse radiolysis at room temperature. Reactions of acetophenone anion radical were also studied for comparison. It was found that the reaction rate of Fl - was subject to the steric and resonance effects of R groups of RX in accord with the classical concept of S N 2 reactions: the rate constant was reduced by 2 orders of magnitude by the steric effect when R was changed from ethyl to bulky isopropyl or t-butyl, and it was still large by the resonance effect of R even if R was changed from ethyl to an allyl or a benzyl group. While the reaction rate of DEF - was not much affected when R was changed to more bulky groups, the rate constant was correlated to the reduction potential of RX. The results were interpreted in terms of a VB correlation diagram approach or rate-equilibrium relationship within a framework of S N 2 reactions. (author)

  16. Pulse radiolysis study of the reactions of catechins with nitrogen dioxide

    International Nuclear Information System (INIS)

    Gebicki, Jerzy L.; Meisner, Piotr; Stawowska, Katarzyna; Gebicka, Lidia

    2012-01-01

    Nitrogen dioxide ( • NO 2 ), one of the oxidizing radicals formed in vivo is suspected to play a role in various pathophysiological processes. The reactions of • NO 2 with dietary catechins, the group of flavonoids present in high amounts in green tea and red wine, have been investigated by pulse radiolysis method. The kinetics of the reaction of • NO 2 with gallic acid have been also studied for comparison. The spectra of transient intermediates are presented. The rate constants of the reaction of • NO 2 with catechin, epigallocatechin, epigallocatechin gallate and gallic acid determined by the competition method with 2,2’-azinobis-(3-ethylbenzthiazoline-6-sulfonate) at pH 7.0 and room temperature have been found to be 0.9, 1.0, 2.3 and 0.5×10 8 M −1 s −1 , respectively. The values for catechins are among the highest reported for the reactions of • NO 2 with non-radical compounds. - Highlight: ► Reaction kinetics of catechins with · NO 2 is studied by the competition method. ► Catechins are excellent · NO 2 scavengers. ► Epigallocatechin gallate is the best · NO 2 scavenger among investigated catechins.

  17. Solvation of the electron in alcohols studied using the Argonne picosecond pulse radiolysis system

    International Nuclear Information System (INIS)

    Jonah, C.D.; Kenney-Wallace, G.A.

    1979-01-01

    With a stroboscopic pulse radiolysis system, it is possible to measure the reactions of solvated electrons and dry electrons and the solvation time of electrons in alcohols from 20 psec to 350 psec. The solvation in alcohol and alcohol-alkane solutions is a complex process which depends on the microscopic structure of the fluid, so that the studies of solvation in alcohols as a function of temperature or as a function of the concentration of the alcohols must take into account the structure of the fluid being studied. The relaxation processes may not be dominant at low temperature. However, in room temperature alcohols, pre-existing traps are the dominant means of electron trapping. The extrapolation to water may be reasonable since water and alcohols both give similar final species. To obtain such idea of the solvation process in alcohols, the change of the absorption of electrons at 500 nm was measured. At very low concentration of alcohols in alkanes, electrons form a complex with a cluster of alcohol molecules, and the most probable size of this cluster is two alcohols (C 4 , C 10 ). The species formed is not solvated electrons, since the characteristic spectrum of solvated electrons is absent, and the conductivity of the species is far above that of solvated electrons. (Yamashita, S.)

  18. A novel low cost pulse excitation source to study trap spectroscopy of persistent luminescent materials

    Science.gov (United States)

    Chandrasekhar, Ngangbam; Singh, Nungleppam Monorajan; Gartia, R. K.

    2018-04-01

    Luminescent techniques require one or the other source of excitations which may vary from high cost X-rays, γ-rays, β-rays etc. to low cost LED. Persistent luminescent materials or Glow-in-the-Dark phosphors are the optical harvesters which store the optical energy from day light illuminating a whole night. They are so sensitive that they can be excited even with the low light of firefly. Therefore, instead of using a high cost excitation source authors have developed a low cost functioning of excitation source controlling short pulses of LED to excite persistent phosphors with the aid of ExpEYES Junior (Hardware/software framework developed by IUAC, New Delhi). Using this, the authors have excited the sample under investigation upto 10 ms. Trap spectroscopy of the pre-excited sample with LED is studied using Thermoluminescence (TL) technique. In this communication, development of the excitation source is discussed and demonstrate the its usefulness in the study of trap spectroscopy of commercially available CaS:Eu2+, Sm3+. Trapping parameters are also evaluated using Computerized Glow Curve Deconvolution (CGCD) technique.

  19. Genome-wide association study identifies six new loci influencing pulse pressure and mean arterial pressure

    Science.gov (United States)

    Wain, Louise V; Verwoert, Germaine C; O’Reilly, Paul F; Shi, Gang; Johnson, Toby; Johnson, Andrew D; Bochud, Murielle; Rice, Kenneth M; Henneman, Peter; Smith, Albert V; Ehret, Georg B; Amin, Najaf; Larson, Martin G; Mooser, Vincent; Hadley, David; Dörr, Marcus; Bis, Joshua C; Aspelund, Thor; Esko, Tõnu; Janssens, A Cecile JW; Zhao, Jing Hua; Heath, Simon; Laan, Maris; Fu, Jingyuan; Pistis, Giorgio; Luan, Jian’an; Arora, Pankaj; Lucas, Gavin; Pirastu, Nicola; Pichler, Irene; Jackson, Anne U; Webster, Rebecca J; Zhang, Feng; Peden, John F; Schmidt, Helena; Tanaka, Toshiko; Campbell, Harry; Igl, Wilmar; Milaneschi, Yuri; Hotteng, Jouke-Jan; Vitart, Veronique; Chasman, Daniel I; Trompet, Stella; Bragg-Gresham, Jennifer L; Alizadeh, Behrooz Z; Chambers, John C; Guo, Xiuqing; Lehtimäki, Terho; Kühnel, Brigitte; Lopez, Lorna M; Polašek, Ozren; Boban, Mladen; Nelson, Christopher P; Morrison, Alanna C; Pihur, Vasyl; Ganesh, Santhi K; Hofman, Albert; Kundu, Suman; Mattace-Raso, Francesco US; Rivadeneira, Fernando; Sijbrands, Eric JG; Uitterlinden, Andre G; Hwang, Shih-Jen; Vasan, Ramachandran S; Wang, Thomas J; Bergmann, Sven; Vollenweider, Peter; Waeber, Gérard; Laitinen, Jaana; Pouta, Anneli; Zitting, Paavo; McArdle, Wendy L; Kroemer, Heyo K; Völker, Uwe; Völzke, Henry; Glazer, Nicole L; Taylor, Kent D; Harris, Tamara B; Alavere, Helene; Haller, Toomas; Keis, Aime; Tammesoo, Mari-Liis; Aulchenko, Yurii; Barroso, Inês; Khaw, Kay-Tee; Galan, Pilar; Hercberg, Serge; Lathrop, Mark; Eyheramendy, Susana; Org, Elin; Sõber, Siim; Lu, Xiaowen; Nolte, Ilja M; Penninx, Brenda W; Corre, Tanguy; Masciullo, Corrado; Sala, Cinzia; Groop, Leif; Voight, Benjamin F; Melander, Olle; O’Donnell, Christopher J; Salomaa, Veikko; d’Adamo, Adamo Pio; Fabretto, Antonella; Faletra, Flavio; Ulivi, Sheila; Del Greco, M Fabiola; Facheris, Maurizio; Collins, Francis S; Bergman, Richard N; Beilby, John P; Hung, Joseph; Musk, A William; Mangino, Massimo; Shin, So-Youn; Soranzo, Nicole; Watkins, Hugh; Goel, Anuj; Hamsten, Anders; Gider, Pierre; Loitfelder, Marisa; Zeginigg, Marion; Hernandez, Dena; Najjar, Samer S; Navarro, Pau; Wild, Sarah H; Corsi, Anna Maria; Singleton, Andrew; de Geus, Eco JC; Willemsen, Gonneke; Parker, Alex N; Rose, Lynda M; Buckley, Brendan; Stott, David; Orru, Marco; Uda, Manuela; van der Klauw, Melanie M; Zhang, Weihua; Li, Xinzhong; Scott, James; Chen, Yii-Der Ida; Burke, Gregory L; Kähönen, Mika; Viikari, Jorma; Döring, Angela; Meitinger, Thomas; Davies, Gail; Starr, John M; Emilsson, Valur; Plump, Andrew; Lindeman, Jan H; ’t Hoen, Peter AC; König, Inke R; Felix, Janine F; Clarke, Robert; Hopewell, Jemma C; Ongen, Halit; Breteler, Monique; Debette, Stéphanie; DeStefano, Anita L; Fornage, Myriam; Mitchell, Gary F; Smith, Nicholas L; Holm, Hilma; Stefansson, Kari; Thorleifsson, Gudmar; Thorsteinsdottir, Unnur; Samani, Nilesh J; Preuss, Michael; Rudan, Igor; Hayward, Caroline; Deary, Ian J; Wichmann, H-Erich; Raitakari, Olli T; Palmas, Walter; Kooner, Jaspal S; Stolk, Ronald P; Jukema, J Wouter; Wright, Alan F; Boomsma, Dorret I; Bandinelli, Stefania; Gyllensten, Ulf B; Wilson, James F; Ferrucci, Luigi; Schmidt, Reinhold; Farrall, Martin; Spector, Tim D; Palmer, Lyle J; Tuomilehto, Jaakko; Pfeufer, Arne; Gasparini, Paolo; Siscovick, David; Altshuler, David; Loos, Ruth JF; Toniolo, Daniela; Snieder, Harold; Gieger, Christian; Meneton, Pierre; Wareham, Nicholas J; Oostra, Ben A; Metspalu, Andres; Launer, Lenore; Rettig, Rainer; Strachan, David P; Beckmann, Jacques S; Witteman, Jacqueline CM; Erdmann, Jeanette; van Dijk, Ko Willems; Boerwinkle, Eric; Boehnke, Michael; Ridker, Paul M; Jarvelin, Marjo-Riitta; Chakravarti, Aravinda; Abecasis, Goncalo R; Gudnason, Vilmundur; Newton-Cheh, Christopher; Levy, Daniel; Munroe, Patricia B; Psaty, Bruce M; Caulfield, Mark J; Rao, Dabeeru C

    2012-01-01

    Numerous genetic loci influence systolic blood pressure (SBP) and diastolic blood pressure (DBP) in Europeans 1-3. We now report genome-wide association studies of pulse pressure (PP) and mean arterial pressure (MAP). In discovery (N=74,064) and follow-up studies (N=48,607), we identified at genome-wide significance (P= 2.7×10-8 to P=2.3×10-13) four novel PP loci (at 4q12 near CHIC2/PDGFRAI, 7q22.3 near PIK3CG, 8q24.12 in NOV, 11q24.3 near ADAMTS-8), two novel MAP loci (3p21.31 in MAP4, 10q25.3 near ADRB1) and one locus associated with both traits (2q24.3 near FIGN) which has recently been associated with SBP in east Asians. For three of the novel PP signals, the estimated effect for SBP was opposite to that for DBP, in contrast to the majority of common SBP- and DBP-associated variants which show concordant effects on both traits. These findings indicate novel genetic mechanisms underlying blood pressure variation, including pathways that may differentially influence SBP and DBP. PMID:21909110

  20. Development of an ultrasonic pulse-echo (UPE) technique for aircraft icing studies

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yang; Hu, Hui [Department of Aerospace Engineering, Iowa State University, 2271 Howe Hall, Room 1200, Ames, IA 50011 (United States); Chen, Wen-Li [Department of Aerospace Engineering, Iowa State University, 2271 Howe Hall, Room 1200, Ames, IA 50011 (United States); School of Civil Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150090 (China); Bond, Leonard J. [Department of Aerospace Engineering, Iowa State University, 2271 Howe Hall, Room 1200, Ames, IA 50011 (United States); Center for Nondestructive Evaluation, Iowa State University, 1915 Scholl Road, 151 ASC II, Ames, IA 50011 (United States)

    2014-02-18

    Aircraft operating in some cold weather conditions face the risk of icing. Icing poses a threat to flight safety and its management is expensive. Removing light frost on a clear day from a medium-size business jet can cost $300, heavy wet snow removal can cost $3,000 and removal of accumulated frozen/freezing rain can cost close to $10,000. Understanding conditions that lead to severe icing events is important and challenging. When an aircraft or rotorcraft flies in a cold climate, some of the super cooled droplets impinging on exposed aircraft surfaces may flow along the surface prior to freezing and give various forms and shapes of ice. The runback behavior of a water film on an aircraft affects the morphology of ice accretion and the rate of formation. In this study, we report the recent progress to develop an Ultrasonic Pulse-Echo (UPE) technique to provide real-time thickness distribution measurements of surface water flows driven by boundary layer airflows for aircraft icing studies. A series of initial experimental investigations are conducted in an ice wind tunnel employing an array of ultrasonic transducers placed underneath the surface of a flat plate. The water runback behavior on the plate is evaluated by measuring the thickness profile variation of the water film along the surface by using the UPE technique under various wind speed and flow rate conditions.

  1. Pulse radiolysis studies of mangiferin: A C-glycosyl xanthone isolated from Mangifera indica

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, B. [Radiation Chemistry and Chemical Dynamics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Priyadarsini, K.Indira [Radiation Chemistry and Chemical Dynamics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)]. E-mail: kindira@apsara.barc.ernet.in; Sudheerkumar, M. [College of Pharmaceutical Sciences, Kasturba Medical College, Manipal 576119 (India); Unnikrishhnan, M.K. [College of Pharmaceutical Sciences, Kasturba Medical College, Manipal 576119 (India); Mohan, H. [Radiation Chemistry and Chemical Dynamics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

    2006-01-15

    Pulse radiolysis technique has been employed to study the reaction of different oxidizing and reducing radicals with mangiferin. The reaction of {sup {center_dot}}OH radical showed the formation of transient species absorbing in 380-390 and 470-480 nm region. The reaction with specific one-electron oxidants (N{sub 3} {sup {center_dot}}, CCl{sub 3}O{sub 2} {sup {center_dot}}) also showed the formation of similar transient absorption bands and is assigned to phenoxyl radicals. The pK {sub a} values of the transient species have been determined to be 6.3 and 11.9. One-electron oxidation potential of mangiferin at pH 9 has been found to be 0.62 V vs. NHE. The reaction of e{sub aq} {sup -} showed the formation of transient species with {lambda} {sub max} at 340 nm, which is assigned to the ketyl anion radical formed on addition of e{sub aq} {sup -} at carbonyl site. Reactions of one-electron oxidised mangiferin radicals with ascorbic acid have also been studied.

  2. Pulse radiolysis studies of mangiferin: A C-glycosyl xanthone isolated from Mangifera indica

    International Nuclear Information System (INIS)

    Mishra, B.; Priyadarsini, K.Indira; Sudheerkumar, M.; Unnikrishhnan, M.K.; Mohan, H.

    2006-01-01

    Pulse radiolysis technique has been employed to study the reaction of different oxidizing and reducing radicals with mangiferin. The reaction of · OH radical showed the formation of transient species absorbing in 380-390 and 470-480 nm region. The reaction with specific one-electron oxidants (N 3 · , CCl 3 O 2 · ) also showed the formation of similar transient absorption bands and is assigned to phenoxyl radicals. The pK a values of the transient species have been determined to be 6.3 and 11.9. One-electron oxidation potential of mangiferin at pH 9 has been found to be 0.62 V vs. NHE. The reaction of e aq - showed the formation of transient species with λ max at 340 nm, which is assigned to the ketyl anion radical formed on addition of e aq - at carbonyl site. Reactions of one-electron oxidised mangiferin radicals with ascorbic acid have also been studied

  3. Pulse radiolysis studies of mangiferin: A C- glycosyl xanthone isolated from Mangifera indica

    Science.gov (United States)

    Mishra, B.; Priyadarsini, K. Indira; Sudheerkumar, M.; Unnikrishhnan, M. K.; Mohan, H.

    2006-01-01

    Pulse radiolysis technique has been employed to study the reaction of different oxidizing and reducing radicals with mangiferin. The reaction of rad OH radical showed the formation of transient species absorbing in 380-390 and 470-480 nm region. The reaction with specific one-electron oxidants (N 3rad , CCl 3O 2rad ) also showed the formation of similar transient absorption bands and is assigned to phenoxyl radicals. The p Ka values of the transient species have been determined to be 6.3 and 11.9. One-electron oxidation potential of mangiferin at pH 9 has been found to be 0.62 V vs. NHE. The reaction of e aq- showed the formation of transient species with λmax at 340 nm, which is assigned to the ketyl anion radical formed on addition of e aq- at carbonyl site. Reactions of one-electron oxidised mangiferin radicals with ascorbic acid have also been studied.

  4. Oxidation of ortho- and para-aminobenzoic acid. A pulse radiolysis- and gamma radiolysis study

    International Nuclear Information System (INIS)

    Solar, Sonja; Getoff, Nikola; Zona, Robert; Solar, Wolfgang

    2011-01-01

    The oxidation of anthranilic acid (ortho-aminobenzoic acid, ANA) and para-aminobenzoic acid (PABA) by · OH, N 3 · and O ·- in basic solution was studied by pulse radiolysis. The kinetic and spectroscopic characteristics of the intermediate transients were determined. For ANA the site attack of the OH radicals was established to be ∼50% on the -NH 2 moiety and ∼50% on the aromatic ring with an overall rate constant k( · OH+ANA)=(5.5x10 9 ) dm 3 mol -1 s -1 . The rate constant of PABA was k( · OH+PABA)=8x10 9 dm 3 mol -1 s -1 . The OH-adducts of both compounds showed a first order decay of 0.8x10 5 and 1.2x10 5 s -1 , respectively, whereby the corresponding anilino-radicals were formed. The rate constant of ANA with solvated electrons was k(e - aq +ANA)=2.9x10 9 dm 3 mol -1 s -1 . The radiation induced decomposition of both substrates was studied by gamma radiolysis as a function of the absorbed dose. They exhibited a distinct radiation resistance, the initial degradation yields were ∼0.16 μmol J -1 , i.e. only 28% of the · OH radicals contributed to their decomposition. The hydroxylation process was of minor importance, the yield of hydroxylated aminobenzoic acids was≤0.01 μmol J -1 .

  5. Experimental study of plume induced by nanosecond repetitively pulsed spark microdischarges in air at atmospheric pressure

    Science.gov (United States)

    Orriere, Thomas; Benard, Nicolas; Moreau, Eric; Pai, David

    2016-09-01

    Nanosecond repetitively pulsed (NRP) spark discharges have been widely studied due to their high chemical reactivity, low gas temperature, and high ionization efficiency. They are useful in many research areas: nanomaterials synthesis, combustion, and aerodynamic flow control. In all of these fields, particular attention has been devoted to chemical species transport and/or hydrodynamic and thermal effects for applications. The aim of this study is to generate an electro-thermal plume by combining an NRP spark microdischarge in a pin-to-pin configuration with a third DC-biased electrode placed a few centimeters away. First, electrical characterization and optical emission spectroscopy were performed to reveal important plasma processes. Second, particle image velocimetry was combined with schlieren photography to investigate the main characteristics of the generated flow. Heating processes are measured by using the N2(C ->B) (0,2) and (1,3) vibrational bands, and effects due to the confinement of the discharge are described. Moreover, the presence of atomic ions N+ and O+ is discussed. Finally, the electro-thermal plume structure is characterized by a flow velocity around 1.8 m.s-1, and the thermal kernel has a spheroidal shape.

  6. Structural, optical and electrical studies on pulse electrodeposited CdIn2S4 thin films

    International Nuclear Information System (INIS)

    Kokate, A.V.; Asabe, M.R.; Shelake, S.B.; Hankare, P.P.; Chougule, B.K.

    2007-01-01

    CdIn 2 S 4 thin films were prepared by pulse electrodeposition technique over F:SnO 2 glass and stainless steel substrates in galvanostatic mode from an aqueous acidic bath containing CdSO 4 , InCl 3 and Na 2 S 2 O 3 . The growth kinetics of the film has been studied and the deposition parameters such as electrolyte bath concentration, bath temperature, time of deposition, deposition current and pH of the bath are optimized. X-ray diffraction (XRD) analysis of the as deposited and annealed films shows polycrystalline nature. Energy dispersive analysis by X-ray (EDAX) confirms nearly stoichiometric CdIn 2 S 4 nature of the film. Scanning electron microscope (SEM) studies show that, the deposited films are well adherent and grains are uniformly distributed over the surface of the substrate. The optical transmission spectra show a direct band gap of 2.16 eV. Conductivity measurements have been carried out at different temperatures and electrical parameters such as activation energy, trapped energy state and barrier heights etc. have been determined

  7. Ozone decomposition in water studied by pulse radiolysis. 2. OH and HO4 as chain intermediates

    International Nuclear Information System (INIS)

    Staehelin, J.; Buehler, R.E.; Hoigne, J.

    1984-01-01

    Ozone decomposition in pure water involves a chain mechanism, initiated by the reaction OH - +O 3 and propogated by O 2 - and OH. In the present studies this chain is initiated by pulse radiolysis of aqueous solutions of ozone. The chain propogation steps were studied in two parts. By computer simulation of the rate curves, it is shown that from OH + O 3 and intermediate HO 4 must be formed, most likely a charge-transfer complex (HO.O 3 ), which eventually decays into HO 2 . The derived rate constants for the formation of the various species are included. The spectrum of HO 4 is derived. It is similar to the one of ozone, but the absorption coefficients are about 50% larger. In the presence of high ozone concentration, the dominant chain termination reactions are HO 4 + HO 4 and HO 4 + HO 3 . The effect on chain length, dose, overall rate, and pH and of added scavengers is described. The implications for the natural ozone decay mechanism are discussed

  8. Taking in account the electromagnetic pulses in study of a material or system

    International Nuclear Information System (INIS)

    Jeannolle, J.

    1985-01-01

    High altitude nuclear bursts generate extremely short and large magnitude electromagnetic pulses (EMP). Electronic circuits which are commonly used nowadays are directly threatened by such an effect. This effect is so important that it has the characteristic to cover large areas, as large as a whole country. For an equipment or a system to stand against such an electromagnetic threat without being considerably disturbed, it is advised to take into account particular protections from the outset of the design phase and during the production phase, that is to say to ensure its hardening. Taking into account and ensuring the EMP protection of an equipment or a system, the Telecommunications Division (DTC) of Thomson-CSF has been devoting to for a number of years. The experience acquired through various studies and production work has allowed a thorough definition of the main steps required in an EMP hardening task: - hardening goal definition; - hardening study and design; - hardening carrying out; - design and production of EMP environment simulators; - hardening validation; - maintenance. This paper describes for each one of these steps: - which approach is undertaken; - which questions are raised; - which documents to constitute [fr

  9. A feasibility study for a one-megawatt pulsed spallation source at Los Alamos National Laboratory

    International Nuclear Information System (INIS)

    Pynn, R.

    1994-01-01

    Over the past two decades, high-intensity proton accelerators have been designed and developed to support nuclear physics research and defense applications. This technology has now matured to the point where it can support simultaneous and cost-effective exploitation of a number of important areas of both basic and applied science. Examples include neutron scattering, the production of radioisotopes, tests of technologies to transmute nuclear waste, radiation damage studies, nuclear physics, and muon spin research. As part of a larger program involving these and other areas, a team at Los Alamos National Laboratory has undertaken a feasibility study for a 1-MW pulsed spallation neutron source (PSS) based on the use of an 800-MeV proton linac and an accumulator ring. In January 1994, the feasibility study was reviewed by a large, international group of experts in the design of accelerators and neutron spallation targets. This group confirmed the viability of the proposed neutron source. In this paper, I describe the approach Los Alamos has taken to the feasibility study, which has involved a synergistic application of the Laboratory's expertise in nuclear science and technology, computation, and particle-beam technologies. Several examples of problems resolved by the study are described, including chopping of low-energy proton beam, interactions between H - particles and the stripper foil used to produce protons for injection into an accumulator ring, and the inclusion of engineering realities into the design of a neutron production target. These examples are chosen to illustrate the breadth of the expertise that has been brought to bear on the feasibility study and to demonstrate that there are real R ampersand D issues that need to be resolved before a next-generation spoliation source can be built

  10. A Study of Tongue and Pulse Diagnosis in Traditional Korean Medicine for Stroke Patients Based on Quantification Theory Type II

    Directory of Open Access Journals (Sweden)

    Mi Mi Ko

    2013-01-01

    Full Text Available In traditional Korean medicine (TKM, pattern identification (PI diagnosis is important for treating diseases. The aim of this study was to comprehensively investigate the relationship between the PI type and tongue diagnosis or pulse diagnosis variables. The study included 1,879 stroke patients who were admitted to 12 oriental medical university hospitals from June 2006 through March 2009. The status of the pulse and tongue was examined in each patient. Additionally, to investigate relatively important indicators related to specialist PI, the quantification theory type II analysis was performed regarding the PI type. In the first axis quantification of the external criteria, the Qi-deficiency and the Yin-deficiency patterns were located in the negative direction, while the dampness-phlegm (DP and fire-heat patterns were located in the positive direction. The explanatory variable with the greatest impact on the assessment was a fine pulse. In the second axis quantification, the external criteria were divided into either the DP or non-DP patterns. The slippery pulse exhibited the greatest effect on the division. This study attempted to build a model using a statistical method to objectively quantify PI and various indicators that constitute the unique diagnosis system of TKM. These results should assist the development of future diagnostic standards in stroke PI.

  11. Nanosecond Pulsed Discharge in Water without Bubbles: A Fundamental Study of Initiation, Propagation and Plasma Characteristics

    Science.gov (United States)

    Seepersad, Yohan

    The state of plasma is widely known as a gas-phase phenomenon, but plasma in liquids have also received significant attention over the last century. Generating plasma in liquids however is theoretically challenging, and this problem is often overcome via liquid-gas phase transition preceding the actual plasma formation. In this sense, plasma forms in gas bubbles in the liquid. Recent work at the Drexel Plasma Institute has shown that nanosecond pulsed electric fields can initiate plasma in liquids without any initial cavitation phase, at voltages below theoretical direct-ionization thresholds. This unique regime is poorly understood and does not fit into any current descriptive mechanisms. As with all new phenomena, a complete fundamental description is paramount to understanding its usefulness to practical applications. The primary goals of this research were to qualitatively and quantitatively understand the phenomenon of nanosecond pulsed discharge in liquids as a means to characterizing properties that may open up niche application possibilities. Analysis of the plasma was based on experimental results from non-invasive, sub-nanosecond time-resolved optical diagnostics, including direct imaging, transmission imaging (Schlieren and shadow), and optical emission spectroscopy. The physical characteristics of the plasma were studied as a function of variations in the electric field amplitude and polarity, liquid permittivity, and pulse duration. It was found that the plasma size and emission intensity was dependent on the permittivity of the liquid, as well as the voltage polarity, and the structure and dynamics were explained by a 'cold-lightning' mechanism. The under-breakdown dynamics at the liquid-electrode interface were investigated by transmission imaging to provide evidence for a novel mechanism for initiation based on the electrostriction. This mechanism was proposed by collaborators on the project and developed alongside the experimental work in this

  12. The impact of left ventricular preload reduction on cardiac pulsed doppler indices during hemodialysis and its relation to intra-dialysis hypotension: A pulsed doppler study

    International Nuclear Information System (INIS)

    Alarrayed, Sameer; Garadah Taysir Said; Alawdi, Abdulhai Ali

    2009-01-01

    Fluid status in the body plays an important role on left ventricular (LV) filling in patients with end-stage renal disease (ESRD) on regular hemodialysis (HD), and plays a role in intra-dialysis hemodynamic derangement. Fifty-two patients with ESRD on regular HD, including 34 males with a mean age of 45.5 +- 13 years (range 18-72 years), were studied. All patients underwent Echo-pulsed Doppler study before and immediately after a HD session. The Echo Doppler indices noted were: LV cavity dimension and wall thickness, LV ejection fraction (LVEF%), trans-mitral early diastolic filling velocity (E wave), atrial filling diastolic velocity (A wave), E/A ratio, Deceleration Time (DT) of E wave, Isovolumic relaxation time (IVRT), Aortic Velocity Integral (AVI) and Inferior Vena Cava Diameter (VCD) at expiration. Patients were divided into two groups according to the amount of net ultra filtrate loss after HD. Group I comprised of 25 patients with fluid loss of 2 liters. During the HD session, each patient was observed for the development of acute clinical events such as arterial hypotension (systolic BP less than 90 mmHg), chest pain and arrhythmias. There was a significant difference between the two groups in the mean values, pre- and post- HD, of reduction of E wave velocity (p < 0.01), the reduction of E/A ratio (p< 0.05), the increment in DT of E wave (p< 0.05), the reduction in AVI (p< 0.01) and the reduction of VCD (p< 0.05). There was no significant difference between the groups in the reduction of A wave velocity and the reduction of IVRT. Among the study patients, 11 (21%) developed systolic hypo-tension during HD. The pre-dialysis mean values of E/A ratio and DT of E wave in patients who developed hypotension compared to those who did not was 0.7 +- 0.2 vs 1.1 +- 0.2.1 (p< 0.001) and 246 +- 40 vs 224 +- 34 msec (p< 0.05), respectively. Our study suggests that preload reduction in patients with ESRD on regular HD is directly proportional to the reduction of left

  13. PERIPHERAL APPLICATION OF REPETITIVE PULSE MAGNETIC STIMULATION ON JOINT CONTRACTURE FOR MOBILITY RESTORATION: CONTROLLED RANDOMIZED STUDY

    Directory of Open Access Journals (Sweden)

    Efthimios J. Kouloulas

    2016-10-01

    Full Text Available Background: Joint contracture is a limitation in the passive or active range of motion (ROM of a joint, where in addition to the mobility limiting factor the pain is also present. Repetitive pulsed Magnetic Stimulation (rPMS appears to be an effective, non-invasive and safety solution for treating this condition. Therefore aim of this study was to evaluate the effect of rPMS in treating joint contracture. Methods: 30 subjects with joint contracture in the knee were enrolled in this study and divided respectively into Treatment and Control group. The treatment group were delivered with rPMS therapy. The control group was delivered with conventional physiotherapy method (ultrasound. The primary outcome measurements were: 1. Mobility evaluation by goniometry (ROM in degrees while performing flexion and Patient Functional Assessment Questionnaire (PFAQ for ability to perform Activities of Daily Living (ADL and 2. Pain evaluation by 10-point Visual Analog Scale (VAS for pain perception. Absence of adverse events was set as a secondary measure. Results: The results of the study show statistical difference (p<0.05 between the levels of improvement of all studied parameters while comparing between both groups. The results suggest greater immobility restoration and pain relieving effect of the rPMS in comparison to conventional physiotherapy method. Conclusion: rPMS an effective and safe non-invasive method for mobility restoration and pain relief in case of joint contractures. This study suggests the method as beneficial and quality of life ameliorating among patients suffering from immobilized joints accompanied by pain.

  14. Studies on pulsed optogalvanic effect in Eu/Ne hollow cathode discharge.

    Science.gov (United States)

    Saini, V K; Kumar, P; Dixit, S K; Nakhe, S V

    2014-07-01

    The optogalvanic (OG) effect has been observed in a Eu/Ne hollow cathode discharge lamp using pulsed laser irradiation. An OG spectrum is recorded in dye laser wavelength region 574–602 nm using a boxcar-averager. In total 41 atomic lines are observed. Of these, 38 lines are assigned to neon transitions. Two lines observed corresponding to wavelengths 576.519 and 601.815 nm are assigned to europium transitions; (4f 7 6s 2 , S 8 7/2 →4f 7 6s6p , zP 6 7/2 ) and (4f 7 6s 2 , S 8 7/2 →4f 7 6s6p , zP 8 9/2 ), respectively, and the remaining line at 582.475 nm could not be assigned. The effect of the discharge current on europium as well as neon OG signals is also studied. At moderate discharge current values, an extra positive peak is observed in neon OG signal for the transition (1s 5 →2p 2 ) at 588.189 nm, which is explained by Penning-ionization process using the quasi-resonant energy transfer interactions between excited neon and europium atoms lying in 2p 2 and D 10 9/2 states, respectively.

  15. Favism inducing agents: a pulse radiolysis study of isouramil and convicine

    International Nuclear Information System (INIS)

    Chevion, M.; Ilan, Y.A.

    1980-01-01

    Isouramil and covicine, substances implicated in precipitating favic crises in glucose-6-phosphate dehydrogenase deficient individuals, have been studied in N 2 O-saturated aqueous solutions by pulse radiolysis, and the kinetics of the reactions of both substances with OH radicals were determined. The products of these reactions are addition intermediates absorbing above 330 nm. The decay of the intermediate(s) formed in the isouramil reaction is a biphasic one, while the decay of the corresponding intermediate for the convicine reaction is characterized by a single constant. By analogy to uracil, it is suggested that the OH radical is added to the double bond at either positions 5 or 6 of the pyrimidine ring forming two different intermediates. Each of these intermediates loses a molecule of water indicated by the observed biphasic decay reaction. For convicine on the other hand, position 5 is blocked by the O-gucosidic bond and the addition of the OH radical could take place only at position 6. Thus, a single intermediate is formed and its decay is a single-phase one. It has been shown that although free radicals could not be detected in the course of the reactions between isouramil and oxygen or with cellular components by electron paramagnetic resonance, isouramil can participate in a uni-electron transfer reacton and can form relatively stable intermediates. Thus, it is speculated that in the red blood cells isouramil could give rise to deleterious free radicals

  16. Phase transition and thermal expansion studies of alumina thin films prepared by reactive pulsed laser deposition.

    Science.gov (United States)

    Balakrishnan, G; Thirumurugesan, R; Mohandas, E; Sastikumar, D; Kuppusami, P; Songl, J I

    2014-10-01

    Aluminium oxide (Al2O3) thin films were deposited on Si (100) substrates at an optimized oxygen partial pressure of 3 x 10(-3) mbar at room temperature by pulsed laser deposition (PLD). The films were characterized by high temperature X-ray diffraction (HTXRD), field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The HTXRD pattern showed the cubic y-Al2O3 phase in the temperature range 300-973 K. At temperatures ≥ 1073 K, the δ and θ-phases of Al2O3 were observed. The mean linear thermal expansion coefficient and volume thermal expansion coefficient of γ-Al2O3 was found to be 12.66 x 10(-6) K(-1) and 38.87 x 10(-6) K(-1) in the temperature range 300 K-1073 K. The field emission scanning electron microscopy revealed a smooth and structureless morphology of the films deposited on Si (100). The atomic force microscopy study indicated the increased crystallinity and surface roughness of the films after annealing at high temperature.

  17. X-ray absorption study of silicon carbide thin film deposited by pulsed laser deposition

    International Nuclear Information System (INIS)

    Monaco, G.; Suman, M.; Garoli, D.; Pelizzo, M.G.; Nicolosi, P.

    2011-01-01

    Silicon carbide (SiC) is an important material for several applications ranging from electronics to Extreme UltraViolet (EUV) space optics. Crystalline cubic SiC (3C-SiC) has a wide band gap (near 2.4 eV) and it is a promising material to be used in high frequency and high energetic electronic devices. We have deposited, by means of pulsed laser deposition (PLD), different SiC films on sapphire and silicon substrates both at mild (650 o C) and at room temperature. The resulted films have different structures such as: highly oriented polycrystalline, polycrystalline and amorphous which have been studied by means of X-ray absorption spectroscopy (XAS) near the Si L 2,3 edge and the C K edge using PES (photoemission spectroscopy) for the analysis of the valence bands structure and film composition. The samples obtained by PLD have shown different spectra among the grown films, some of them showing typical 3C-SiC absorption structure, but also the presence of some Si-Si and graphitic bonds.

  18. A study of direct- and pulse-current chromium electroplating on rotating cylinder electrode (RCE)

    International Nuclear Information System (INIS)

    Chang, J.H.; Hsu, F.Y.; Liao, M.J.; Huang, C.A.

    2007-01-01

    Direct- and pulse-current (DC and PC) chromium electroplating on Cr-Mo steel were performed in a sulfate-catalyzed chromic acid solution at 50 deg. C using a rotating cylinder electrode (RCE). The electroplating cathodic current densities were at 30, 40, 50 and 60 A dm -2 , respectively. The relationship between electroplating current efficiency and the rotating speed of the RCE was studied. The cross-sectional microstructure of Cr-deposit was examined by transmission electron microscope (TEM). Results showed that DC-plating exhibited higher current efficiency than the PC-plating under the same conditions of electroplating current density and the rotating speed. We found the critical rotating speed of RCE used in the chromium electroplating, above this rotating speed the chromium deposition is prohibited. At the same plating current density, the critical rotating speed for DC-plating was higher than that for PC-plating. The higher plating current density is, the larger difference in critical rotating speeds appears between DC- and PC-electroplating. Equiaxed grains, in a nanoscale size with lower dislocation density, nucleate on the cathodic surface in both DC- and PC-electroplating. Adjacent to the equiaxed grains, textured grains were found in other portion of chromium deposit. Fine columnar grains were observed in the DC-electroplated deposit. On the other hand, very long slender grains with high degree of preferred orientation were detected in PC-electroplated deposit

  19. A pulse-radiolysis study of the manganese-containing superoxide dismutase from Bacillus stearothermophilus

    International Nuclear Information System (INIS)

    McAdam, M.E.; Fox, R.A.; Lavelle, F.; Fielden, E.M.

    1977-01-01

    The enzymic reaction mechanism of a manganese-containing superoxide dismutase from Bacillus stearothermophilus was studied by using pulse radiolysis. During catalysis (pH 8.9; 25 0 C), changes occurring in the kinetics of substrate disappearance and in the visible absorption of the enzyme at 480 nm established that the simple two-step mechanism found for copper- and iron-containing superoxide dismutases was not involved. At a low ratio ( 2 sup(-.) was close to exponential, whereas at much higher ratios (> 100) the observed decay was predominantly zero-order. The simplest interpretation of the results invokes a rapid one-electron oxidation-reduction cycle ('the fast cycle') and, concurrently, a slower reaction giving a form of the enzyme that is essentially unreactive towards O 2 sup(-.) but which undergoes a first-order decay to yield fully active native enzyme ('the slow cycle'). The fast cycle involved the native enzyme Esub(A) and a form of the enzyme Esub(B) which could be obtained also be treating the form Esub(A) with H 2 O 2 . Computer calculations made with such a simple model predicted behaviour in excellent agreement with the observed results. (author)

  20. A pulse-radiolysis study of the manganese-containing superoxide dismutase from Bacillus stearothermophilus

    International Nuclear Information System (INIS)

    McAdam, M.E.; Lavelle, F.; Fox, R.A.; Fielden, E.M.

    1977-01-01

    The mechanism of catalysis of the manganese-containing superoxide dismutase from Bacillus stearothermophilus has been shown to involve a 'fast cycle' and a 'slow cycle' (McAdam, M.E., Fox, R.A., Lavelle, F., and Fielden, E.M., Biochem. J.; 165:71 (1977)). Further properties of the enzyme are now considered. Pulse-radiolysis studies, under conditions of low substrate concentration to enzyme concentration (i.e. when the fast cycle predominates), showed that enzyme activity decreases as pH increases (6.5 to 10.2). Activity was unaffected by the addition of H 2 O 2 or NaN 3 but slightly decreased by KCN. Both H 2 O 2 and the reducing radical anion CO 2 sup(-.) caused a decrease in A 480 of the native enzyme. The rate of the fast catalytic cycle was independent of temperature (5 to 55 0 C), and as temperature increased the slow catalytic cycle became relatively more important. Arrhenius parameters of the rate constants were estimated. The possible identity of the various forms of the enzyme is considered. (author)

  1. Space charge beam dynamics studies for a pulsed spallation source accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Y.; Lessner, E.

    1995-12-31

    Feasibility studies for 2-GeV, 1-MW and 10-GeV, 5-MW rapid cycling synchrotrons (RCS) for spallation neutron sources have been completed. Both synchrotrons operate at a repetition rate of 30 Hz, and accelerate 1.04 {times} 10{sup 14} protons per pulse. The injection energy of the 2-GeV ring is 400 MeV, and the 10-GeV RCS accepts the beam from the 2-GeV machine. Work performed to-date includes calculation of the longitudinal space charge effects in the 400-MeV beam transfer line, and of both longitudinal and transverse space charge effects during the injection, capture and acceleration processes in the two rings. Results of space charge calculations in the rings led to proper choices of the working points and of rf voltage programs that prevents beam loss. Space charge effects in the 2-GeV synchrotron, in both transverse and longitudinal phase space, have major impact on the design due to the fact that the injection energy is 400 MeV. The design achieves the required performance while alleviating harmful effects due to space charge.

  2. Studies on perovskite film ablation and scribing with ns-, ps- and fs-laser pulses

    Science.gov (United States)

    Bayer, Lukas; Ye, Xinyuan; Lorenz, Pierre; Zimmer, Klaus

    2017-10-01

    Hybrid organic-inorganic perovskites attract much attention due to their exceptional optoelectronic properties, in particular for photovoltaic (PV) applications. The accurate, high-speed and reliable patterning of the PV films is required for perovskite solar modules fabrication. Laser scribing provides these characteristics needed for industrial fabrication processes. In this work, the laser ablation and scribing of perovskite layers (CH3NH3PbI3: MAPbI3) with different laser sources (ns-, ps-, fs-laser pulses with wavelengths of 248 nm to 2.5 µm) were systematically investigated. The perovskite material was irradiated from both the film side and the substrate (rear side) side to study and compare the particular processes. The patterning results of the perovskite film can be classified into (1) regular laser ablation, (2) thin-film delamination lift-off process, and (3) lift-off with thermal modifications. A particular process, the localised lift-off of single grains from the perovskite film, has been observed and is discussed in relation to the thin-film lift-off process. Ablation and ablation-related mechanisms provide good conditions for laser scribing of the perovskite layer required for module interconnection via P2.

  3. Ligand exchange reactions of the heme group in hemoglobin and myoglobin as studied by pulse radiolysis

    International Nuclear Information System (INIS)

    Raap, I.A.

    1978-01-01

    In this thesis, the kinetic aspects of the ligand exchange reactions of hemoglobin are studied using the pulse radiolysis technique, in particular, the reactions of hydrated electrons with methemoglobin. A hitherto unobserved transient state of the heme group is observed which appears immediately after the rapid reduction process. The absorption spectrum of this new species has the characteristics of a ferrous low-spin state and can therefore be ascribed to the formation of a hemochrome non-equilibrium state. The subsequent relaxation of this intermediate structure into a deoxy-conformation is dependent on the amount of proton activity in the solution and on the presence of organic and inorganic phosphate anions. The final absorption spectrum of the heme group is shown to correspond to a ferrous high-spin state in the relaxed quaternary conformation. This is in agreement with the kinetics observen the binding of carbon monoxide and oxygen to partially reduced methemoglobin. At reduction degrees of methemoglobin as well as of valncy 8ybrids where there is an important contribution from species with two reduced subunits, the binding of carbon monoxide to hemoglobin occurs with on-rate constants characteristic for the tensed quaternary conformation. It is argued that this conformational change of hemoglobin (the R-to-T transition) takes place very rapidly, which suggests the participation of an activated relaxed conformation. In addition, it is found that there is a distinct heterogeneity in the binding of oxygen to partially reduced methemoglobin even at low degrees of reduction

  4. Microdosimetric study for nanosecond pulsed electric fields on a cell circuit model with nucleus.

    Science.gov (United States)

    Denzi, Agnese; Merla, Caterina; Camilleri, Paola; Paffi, Alessandra; d'Inzeo, Guglielmo; Apollonio, Francesca; Liberti, Micaela

    2013-10-01

    Recently, scientific interest in electric pulses, always more intense and shorter and able to induce biological effects on both plasma and nuclear membranes, has greatly increased. Hence, microdosimetric models that include internal organelles like the nucleus have assumed increasing importance. In this work, a circuit model of the cell including the nucleus is proposed, which accounts for the dielectric dispersion of all cell compartments. The setup of the dielectric model of the nucleus is of fundamental importance in determining the transmembrane potential (TMP) induced on the nuclear membrane; here, this is demonstrated by comparing results for three different sets of nuclear dielectric properties present in the literature. The results have been compared, even including or disregarding the dielectric dispersion of the nucleus. The main differences have been found when using pulses shorter than 10 ns. This is due to the fact that the high spectral components of the shortest pulses are differently taken into account by the nuclear membrane transfer functions computed with and without nuclear dielectric dispersion. The shortest pulses are also the most effective in porating the intracellular structures, as confirmed by the time courses of the TMP calculated across the plasma and nuclear membranes. We show how dispersive nucleus models are unavoidable when dealing with pulses shorter than 10 ns because of the large spectral contents arriving above 100 MHz, i.e., over the typical relaxation frequencies of the dipolar mechanism of the molecules constituting the nuclear membrane and the subcellular cell compartments.

  5. Study of Coherence Limits and Chirp Control in Long Pulse FEL Oscillator

    CERN Document Server

    Gover, Avraham; Socol, Yehoshua; Volshonok, Mark

    2004-01-01

    Electrostatic Accelerator FELs have the capacity to generate long pulses of tens microseconds and more, that in principle can be elongated indefinitely (CW operation). This allows the generation of very coherent radiation. The fundamental linewidth is extremely narrow [1], and in practice the spectral width is limited by the pulse duration (Fourier transform limit) and e-beam stability. Practical problems such as the accelerator terminal voltage drop due to a non-ideal electron beam transport may reduce the length of the radiation pulse and hence create a limiting factor for coherence measurement. The current status of the Israeli Tandem Electrostatic Accelerator FEL allows the generation of pulses of tens microseconds duration. It has been operated recently past saturation, and produces single mode coherent radiation of relative linewidth ~Δf/f=10-5 at frequencies near 100GHz. A clear frequency chirp is observed during pulses of tens of microseconds (0.1-1 MHz/mS), and is directly proportional to th...

  6. Pulsed dye laser application in ablation of vascular ectasias of the larynx: a preliminary animal study

    Science.gov (United States)

    Woo, Peak; Wang, Zhi; Perrault, Donald F., Jr.; McMillan, Kathleen; Pankratov, Michail M.

    1995-05-01

    Vascular ectasias (dilatation) and vascular lesions of the larynx are difficult to treat with exciting modalities. Varix (enlarged vessel) of the vocal folds, vocal fold hemorrhage, vascular polyp, hemangioma, intubation or contact granuloma are common problems which disturb voice. Current applications of CO2 laser and cautery often damage the delicate vocal fold cover. The 585 nm dermatologic pulsed dye laser may be an ideal substitute. Two adult canines were examined under anesthesia via microlaryngoscopy technique. Pulsed dye laser (SPTL-1a, Candela Laser Corp., Wayland, MA) energy was delivered via the micromanipulator with the 3.1-mm spot size in single pulses of 6, 8, and 10 Joules/cm2 and applied to the vessels of the vocal folds, epiglottis, and arytenoid cartilage. Endoscopic examination was carried out immediately after the treatment and at 4 weeks postoperatively. The animals were sacrificed at 3 weeks, larynges excised, and whole organ laryngeal section were prepared for histology. Pulsed dye laser thrombosed vessels of the vocal fold using 6 or 8 Joules/cm2. Vascular break and leakage occurred at 10 Joules/cm2. Follow up examination showed excellent vessel obliteration or thrombosis without scarring or injury to the overlying tissues. Histologic examination shows vascular thrombosis without inflammation and fibrosis in the vocal fold cover. Pulsed dye laser may have promise in treatment of vascular lesions of the larynx and upper airway.

  7. Enhancing caries resistance with a short-pulsed CO2 9.3-μm laser: a laboratory study (Conference Presentation)

    Science.gov (United States)

    Rechmann, Peter; Rechmann, Beate M.; Groves, William H.; Le, Charles; Rapozo-Hilo, Marcia L.; Featherstone, John D. B.

    2016-02-01

    The objective of this laboratory study was to test whether irradiation with a new 9.3µm microsecond short-pulsed CO2-laser enhances enamel caries resistance with and without additional fluoride applications. 101 human enamel samples were divided into 7 groups. Each group was treated with different laser parameters (Carbon-dioxide laser, wavelength 9.3µm, 43Hz pulse-repetition rate, pulse duration between 3μs to 7μs (1.5mJ/pulse to 2.9mJ/pulse). Using a pH-cycling model and cross-sectional microhardness testing determined the mean relative mineral loss delta Z (∆Z) for each group. The pH-cycling was performed with or without additional fluoride. The CO2 9.3μm short-pulsed laser energy rendered enamel caries resistant with and without additional fluoride use.

  8. A Pulsed Electric Field (PEF) bench static system to study bacteria inactivation

    International Nuclear Information System (INIS)

    Cortese, Pietro; Dellacasa, Giuseppe; Gemme, Roberto; Bonetta, Sara; Bonetta, Silvia; Carraro, Elisabetta; Motta, Francesca; Paganoni, Marco; Pizzichemi, Marco

    2011-01-01

    Pulsed Electric Fields (PEF) technology is a promising non-thermal processing method for inactivation of microorganisms. A small PEF bench system able to treat a 0.4 ml static liquid volume has been built and tested at the laboratories of the Universita del Piemonte Orientale in Alessandria, Italy. The technique used to produce the required fields consists of charging high voltage cables of various lengths and subsequently discharge them on a cylindrical cell. The pulse intensity can be adjusted to reach a maximum electric field in the cell of about 35 kV/cm and the pulse frequency can reach 10 Hz. We describe the PEF system in some detail and, as a benchmark of its performances, we report preliminary results obtained on Escherichia coli (ATCC 25922) at 10 9 Cfu/ml concentration suspended in a McIlvaine buffer (pH 7.2).

  9. Study of pulse stretching in high current power supplies using multipulse techniques

    International Nuclear Information System (INIS)

    Trendler, R.C.

    1977-01-01

    Considerable interest exists at Fermilab to increase the pulse width of the Neutrino Focusing Horn to permit an increase in beam spill length from twenty (20) microseconds to one (1) millisecond. Two techniques to do this were examined: (1) a high current transformer, and (2) increased bank capacitance using the multi-power supply technique. The transformer is the most straightforward conceptually; it is, however, a complicated device requiring sizable changes to the existing horn power supply. This alternative is briefly reviewed. The second scheme involves pulsing a 20 kv 200 ka power supply to establish the required load current and then maintaining this current by the sequential pulsing of a number of low voltage high current power supplies. This alternative is discussed in detail with the results of tests performed on the Fermilab Focusing Horn System

  10. Effects of Acupuncture Stimulation on the Radial artery’s Pressure Pulse Wave in Healthy Young Participants: Protocol for a prospective, single-Arm, Exploratory, Clinical Study

    Directory of Open Access Journals (Sweden)

    Jae-Young Shin

    2016-09-01

    Full Text Available Introduction: This study aims to investigate the effects of acupuncture stimulation on the radial artery’s pressure pulse wave, along with various hemodynamic parameters, and to explore the possible underlying mechanism of pulse diagnosis in healthy participants in their twenties. Methods and analysis: This study is a prospective, si

  11. Gas phase pulse radiolysis

    International Nuclear Information System (INIS)

    Jonah, C.D.; Andong Liu; Mulac, W.A.

    1987-01-01

    Gas phase pulse radiolysis, a technique which can be used to study many different phenomena in chemistry and physics, is discussed. As a source of small radicals, pulse radiolysis is important to the field of chemistry, particularly to combustion and atmospheric kinetics. The reactions of 1,3-butadiene, allene, ethylene and acetylene with OH are presented. 52 refs., 1 fig., 1 tab

  12. A STUDY ABOUT CELL ACTIVITY ON ANODIZED Ti-6Al-4V BY MEANS OF PULSED CURRENT

    Directory of Open Access Journals (Sweden)

    LUANA M. R. VASCONCELLOS

    2017-05-01

    Full Text Available Titanium and some of its alloys exhibit excellent anti-corrosive and biocompatibility properties due to rapid formation of a passive film on their surfaces when exposed to the atmosphere. However, such materials presentpoor osteoindutive properties. Surfaces modified via anodization are being proposed in this study to promote a chemical interaction between implants and bone cells. For this purpose, samples in Ti-6Al-4V alloy discs were anodized in a phosphoric acid solution using pulsed current for being applied in orthopaedic implants. The pulsed current is based on duty cycle (DC, which was supplied by a square wave pulse rectifier at 100 Hz and maximum tension of 30 V. A scanning electron microscope was used to obtain images of the anodized surfaces, thus revealing the presence of uniformly distributed pores over the entire surface, measuring approximately 2 m in diameter. Osteogenic cells grown on the surface of the control and anodized samples were assayed for cytotoxicity and mineralized matrix formation. The anodized surfaces presented a higher rate of viable cells after 10 days, as well as a higher amount of nodules (p = 0.05. In conclusion, these results suggest that the nanotopography promoted by anodization using pulsed current induces beneficial modulatory effects on osteoblastic cells.

  13. Ankle Blood Pressure and Pulse Pressure as Predictors of Cerebrovascular Morbidity and Mortality in a Prospective Follow-Up Study

    Directory of Open Access Journals (Sweden)

    Heikki J. Hietanen

    2010-01-01

    Full Text Available Background and Objective. We examined the association of elevated ankle blood pressure (ABP, together with exercise blood pressure, with incident cerebrovascular (CV morbidity and mortality in a prospective follow-up study of 3,808 patients. The results were compared with pulse pressure, another indicator of arterial stiffness. Methods. Patients with normal ankle and exercise brachial blood pressures were taken as the reference group. Pulse pressure was considered as quartiles with the lowest quartile as the reference category. Results. A total of 170 subjects had a CV event during the follow-up. Multivariate adjusted hazard ratio of a CV event was 2.24 (95% CI 1.43–3.52, <.0001 in patients with abnormal ABP. The pulse pressure was significant only in the model adjusted for age and sex. Conclusion. The risk of a future CV event was elevated already in those patients among whom elevated ABP was the only abnormal finding. As a risk marker, ABP is superior to the pulse pressure.

  14. Preventing Electromagnetic Pulse Irradiation Damage on Testis Using Selenium-rich Cordyceps Fungi. A Preclinical Study in Young Male Mice.

    Science.gov (United States)

    Miao, Xia; Wang, Yafeng; Lang, Haiyang; Lin, Yanyun; Guo, Qiyan; Yang, Mingjuan; Guo, Juan; Zhang, Yanjun; Zhang, Jie; Liu, Junye; Liu, Yaning; Zeng, Lihua; Guo, Guozhen

    2017-02-01

    Networked 21st century society, globalization, and communications technologies are paralleled by the rise of electromagnetic energy intensity in our environments and the growing pressure of the environtome on human biology and health. The latter is the entire complement of environmental factors, including the electromagnetic energy and the technologies that generate them, enacting on the digital citizen in the new century. Electromagnetic pulse (EMP) irradiation might have serious damaging effects not only on electronic equipment but also in the whole organism and reproductive health, through nonthermal effects and oxidative stress. We sought to determine whether EMP exposure (1) induces biological damage on reproductive health and (2) the extent to which selenium-rich Cordyceps fungi (daily coadministration) offer protection on the testicles and spermatozoa. In a preclinical randomized study, 3-week-old male BALB/c mice were repeatedly exposed to EMP (peak intensity 200 kV/m, pulse edge 3.5 ns, pulse width 15 ns, 0.1 Hz, and 400 pulses/day) 5 days per week for four consecutive weeks, with or without coadministration of daily selenium-rich Cordyceps fungi (100 mg/kg). Testicular index and spermatozoa formation were measured at baseline and 1, 7, 14, 28, and 60 day time points after EMP exposure. The group without Cordyceps cotreatment displayed decreased spermatozoa formation, shrunk seminiferous tubule diameters, and diminished antioxidative capacity at 28 and 60 days after exposure (p digital citizenship.

  15. Achieved versus intended pulse oximeter saturation in infants born less than 28 weeks' gestation: the AVIOx study.

    Science.gov (United States)

    Hagadorn, James I; Furey, Anne M; Nghiem, Tuyet-Hang; Schmid, Christopher H; Phelps, Dale L; Pillers, De-Ann M; Cole, Cynthia H

    2006-10-01

    The objective of this study was to document pulse oximeter saturation levels achieved in the first 4 weeks of life in infants who were born at signal-extraction oximeters for a 72-hour period in each of the first 4 weeks of life. Data were compared with the pulse oximeter saturation target range prescribed by local institutional policy. Factors that were associated with intended range compliance were identified with hierarchical modeling. Fourteen centers from 3 countries enrolled 84 infants with mean +/- SD birth weight of 863 +/- 208 g and gestational age of 26 +/- 1.4 weeks. Oxygen saturation policy limits ranged between 83% and 92% for lower limits and 92% and 98% for upper limits. For infants who received respiratory support, median pulse oximeter saturation level achieved was 95%. Center-specific medial levels were within the intended range at 12 centers. Centers maintained infants within their intended range 16% to 64% of the time but were above range 20% to 73% of the time. In hierarchical modeling, wider target ranges, higher target range upper limits, presence of a policy of setting oximeter alarms close to the target range limits, and lower gestational age were associated with improved target range compliance. Success with maintaining the intended pulse oximeter saturation range varied substantially among centers, among patients within centers, and for individual patients over time. Most noncompliance was above the intended range. Methods for improving compliance and the effect of improved compliance on neonatal outcomes require additional research.

  16. Study on automatic control of high uranium concentration solvent extraction with pulse sieve-plate column

    International Nuclear Information System (INIS)

    You Wenzhi; Xing Guangxuan; Long Maoxiong; Zhang Jianmin; Zhou Qin; Chen Fuping; Ye Lingfeng

    1998-01-01

    The author mainly described the working condition of the automatic control system of high uranium concentration solvent extraction with pulse sieve-plate column on a large scale test. The use of the automatic instrument and meter, automatic control circuit, and the best feedback control point of the solvent extraction processing with pulse sieve-plate column are discussed in detail. The writers point out the success of this experiment on automation, also present some questions that should be cared for the automatic control, instruments and meters in production in the future

  17. Neutron powder diffraction at a pulsed neutron source: a study of resolution effects

    International Nuclear Information System (INIS)

    Faber, J. Jr.; Hitterman, R.L.

    1985-11-01

    The General Purpose Powder Diffractometer (GPPD), a high resolution (Δd/d = 0.002) time-of-flight instrument, exhibits a resolution function that is almost independent of d-spacing. Some of the special properties of time-of-flight scattering data obtained at a pulsed neutron source will be discussed. A method is described that transforms wavelength dependent data, obtained at a pulsed neutron source, so that standard structural least-squares analyses can be applied. Several criteria are given to show when these techniques are useful in time-of-flight data analysis. 14 refs., 6 figs., 1 tab

  18. Experimental study of mechanical response of artificial tissue models irradiated with Nd:YAG nanosecond laser pulses

    Science.gov (United States)

    Pérez-Gutiérrez, Francisco G.; Camacho-López, Santiago; Aguilar, Guillermo

    2011-07-01

    Nanosecond long laser pulses are used in medical applications where precise tissue ablation with minimal thermal and mechanical collateral damage is required. When a laser pulse is incident on a material, optical energy will be absorbed by a combination of linear and nonlinear absorption according to both: laser light irradiance and material properties. In the case of water or gels, the first results in heat generation and thermoelastic expansion; while the second results in an expanding plasma formation that launches a shock wave and a cavitation/boiling bubble. Plasma formation due to nonlinear absorption of nanosecond laser pulses is originated by a combination of multiphoton ionization and thermionic emission of free electrons, which is enhanced when the material has high linear absorption coefficient. In this work, we present three experimental approaches to study pressure transients originated when 6 ns laser pulses are incident on agar gels and water with varying linear absorption coefficient, using laser radiant exposures above and below threshold for bubble formation: (a) PVDF sensors, (b) Time-resolved shadowgraphy and (c) Time-resolved interferometry. The underlying hypothesis is that pressure transients are composed of the superposition of both: shock wave originated by hot expanding plasma resulting from nonlinear absorption of optical energy and, thermoelastic expansion originated by heat generation due to linear absorption of optical energy. The objective of this study is to carry out a comprehensive experimental analysis of the mechanical effects that result when tissue models are irradiated with nanosecond laser pulses to elucidate the relative contribution of linear and nonlinear absorption to bubble formation. Furthermore, we investigate cavitation bubble formation with temperature increments as low as 3 °C.

  19. Multi-parametric study of temperature and thermal damage of tumor exposed to high-frequency nanosecond-pulsed electric fields based on finite element simulation.

    Science.gov (United States)

    Mi, Yan; Rui, Shaoqin; Li, Chengxiang; Yao, Chenguo; Xu, Jin; Bian, Changhao; Tang, Xuefeng

    2017-07-01

    High-frequency nanosecond-pulsed electric fields were recently introduced for tumor or abnormal tissue ablation to solve some problems of conventional electroporation. However, it is necessary to study the thermal effects of high-field-intensity nanosecond pulses inside tissues. The multi-parametric analysis performed here is based on a finite element model of liver tissue with a tumor that has been punctured by a pair of needle electrodes. The pulse voltage used in this study ranges from 1 to 4 kV, the pulse width ranges from 50 to 500 ns, and the repetition frequency is between 100 kHz and 1 MHz. The total pulse length is 100 μs, and the pulse burst repetition frequency is 1 Hz. Blood flow and metabolic heat generation have also been considered. Results indicate that the maximum instantaneous temperature at 100 µs can reach 49 °C, with a maximum instantaneous temperature at 1 s of 40 °C, and will not cause thermal damage during single pulse bursts. By parameter fitting, we can obtain maximum instantaneous temperature at 100 µs and 1 s for any parameter values. However, higher temperatures will be achieved and may cause thermal damage when multiple pulse bursts are applied. These results provide theoretical basis of pulse parameter selection for future experimental researches.

  20. Study on laser welding of austenitic stainless steel by varying incident angle of pulsed laser beam

    Science.gov (United States)

    Kumar, Nikhil; Mukherjee, Manidipto; Bandyopadhyay, Asish

    2017-09-01

    In the present work, AISI 304 stainless steel sheets are laser welded in butt joint configuration using a robotic control 600 W pulsed Nd:YAG laser system. The objective of the work is of twofold. Firstly, the study aims to find out the effect of incident angle on the weld pool geometry, microstructure and tensile property of the welded joints. Secondly, a set of experiments are conducted, according to response surface design, to investigate the effects of process parameters, namely, incident angle of laser beam, laser power and welding speed, on ultimate tensile strength by developing a second order polynomial equation. Study with three different incident angle of laser beam 89.7 deg, 85.5 deg and 83 deg has been presented in this work. It is observed that the weld pool geometry has been significantly altered with the deviation in incident angle. The weld pool shape at the top surface has been altered from semispherical or nearly spherical shape to tear drop shape with decrease in incident angle. Simultaneously, planer, fine columnar dendritic and coarse columnar dendritic structures have been observed at 89.7 deg, 85.5 deg and 83 deg incident angle respectively. Weld metals with 85.5 deg incident angle has higher fraction of carbide and δ-ferrite precipitation in the austenitic matrix compared to other weld conditions. Hence, weld metal of 85.5 deg incident angle achieved higher micro-hardness of ∼280 HV and tensile strength of 579.26 MPa followed by 89.7 deg and 83 deg incident angle welds. Furthermore, the predicted maximum value of ultimate tensile strength of 580.50 MPa has been achieved for 85.95 deg incident angle using the developed equation where other two optimum parameter settings have been obtained as laser power of 455.52 W and welding speed of 4.95 mm/s. This observation has been satisfactorily validated by three confirmatory tests.

  1. A search for upstream pressure pulses associated with flux transfer events: An AMPTE/ISEE case study

    Science.gov (United States)

    Elphic, R. C.; Baumjohann, W.; Cattell, C. A.; Luehr, H.; Smith, M. F.

    1994-01-01

    On September 19, 1984, the Active Magnetospheric Particle Tracers Explorers (AMPTE) United Kingdom Satellite (UKS) and Ion Release Module (IRM) and International Sun Earth Explorers (ISEE) 1 and 2 spacecraft passed outbound through the dayside magnetopause at about the same time. The AMPTE spacecraft pair crossed first and were in the near-subsolar magnetosheath for more than an hour. Meanwhile the ISEE pair, about 5 R(sub E) to the south, observed flux transfer event (FTE) signatures. We use the AMPTE UKS and IRM plasma and field observations of magnetosheath conditions directly upstream of the subsolar magnetopause to check whether pressure pulses are responsible for the FTE signatures seen at ISEE. Pulses in both the ion thermal pressure and the dynamic pressure are observed in the magnetosheath early on when IRM and UKS are close to the magnetopause, but not later. These large pulses appear to be related to reconnection going on at the magnetopause nearby. AMPTE magnetosheath data far from the magnetopause do not show a pressure pulse correlation with FTEs at ISEE. Moreover, the magnetic pressure and tension effects seen in the ISEE FTEs are much larger than any pressure effects seen in the magnetosheath. A superposed epoch analysis based on small-amplitude peaks in the AMPTE magnetosheath total static pressure (nkT + B(exp 2)/2 mu(sub 0)) hint at some boundary effects, less than 5 nT peak-to-peak variations in the ISEE 1 and 2 B(sub N) signature starting about 1 min after the pressure peak epoch. However, these variations are much smaller than the standard deviations of the B(sub N) field component. Thus the evidence from this case study suggests that upstream magnetosheath pressure pulses do not give rise to FTEs, but may produce very small amplitude signatures in the magnetic field at the magnetopause.

  2. Experimental study of a diod with magnetic insulation at the pulse duration more or equal to 10-5 s

    International Nuclear Information System (INIS)

    Rojfe, I.M.; Burtsev, V.A.; Vasilevskij, M.A.; Ehngel'ko, V.I.

    1980-01-01

    Results of the experimental investigation of a heavy-current diod with magnetic insulation are presented. Diod characteristics dependence on magnetic field distribution and magnitude in the accelerating interval has been studied. It is noted that the magnetic insulation of the accelerating tube has permitted to obtain the pulse duration of > or approximately 10 sub(s)sup(-5) at the voltage of > or approximately 400 kV in the tube and electron beam current of 3-4 kA. Maximum insulating magnetic field is 2.5 kOe. It is shown that the pulse duration of electron current in diods with magnetic insulation is limitted by break-down development along the accelerating tube surface. When magnetic field on the cathode is approximately 5kOe thre is a time interval of 4-5μs when the impedance is constant. The difference of diod impedance behaviour in time in these two cases are defined by a distinct expansion of cathode plasma at low magnetic fields. Cathode lateral surface plays a significant role in the process of plasma expantion. When the interelectrode gap is 3-5 cm and the voltage amplitude - < or approximately 400 kV it is possible to obtain tubular electron beams with the pulse duration of 10-15 μs, beam energy of 5-6 kJat a relatively small (approximately equal to 5kOe) magnitudes of magnetic field on the cathode. A possibility is shown to use multipoint graphite cathodes with a large area for obtaining tubular beams. The tubular electron beam of approximately equal to 400 A with the pulse duration of 25 μs have been obtained in the first experiments with such cathode at the voltage amplitude of < or approximately 150 kV. The conclusion is made that the tube magnetic isolation permits to increase considerably the pulse duration

  3. Picosecond pulse radiolysis studies to understand the primary processes in radiolysis

    International Nuclear Information System (INIS)

    Jonah, C.D.; Lewis, M.A.

    1984-01-01

    The use of pulse radiolysis to learn about processes which occur before the beginning of chemical times is discussed. Two examples, the distance distribution of positive and negative ions in hydrocarbons, and the state of the dry electron are discussed in detail

  4. Picosecond pulse radiolysis studies to understand the primary processes in radiolysis

    Energy Technology Data Exchange (ETDEWEB)

    Jonah, C.D.; Lewis, M.A.

    1984-01-01

    The use of pulse radiolysis to learn about processes which occur before the beginning of chemical times is discussed. Two examples, the distance distribution of positive and negative ions in hydrocarbons, and the state of the dry electron are discussed in detail.

  5. Field emission study of pulsed laser deposition of gold on clean and oxidized tungsten tip

    Czech Academy of Sciences Publication Activity Database

    Plšek, Jan

    2014-01-01

    Roč. 292, FEB 2014 (2014), s. 717-725 ISSN 0169-4332 R&D Projects: GA MŠk LH13022 Institutional support: RVO:61388955 Keywords : nanoparticles * nucleation and growth * pulsed laser deposition Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.711, year: 2014

  6. Comparative study of pulsed laser cleaning applied to weathered marble surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz, P., E-mail: mportcal@upo.es [Department of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, 41013 Seville (Spain); Antúnez, V.; Ortiz, R.; Martín, J.M. [Department of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, 41013 Seville (Spain); Gómez, M.A. [Instituto Andaluz de Patrimonio Histórico, Camino de los Descubrimientos s/n, 41092 Seville (Spain); Hortal, A.R.; Martínez-Haya, B. [Department of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, 41013 Seville (Spain)

    2013-10-15

    The removal of unwanted matter from surface stones is a demanding task in the conservation of cultural heritage. This paper investigates the effectiveness of near-infrared (IR) and ultraviolet (UV) laser pulses for the cleaning of surface deposits, iron oxide stains and different types of graffiti (black, red and green sprays and markers, and black cutting-edge ink) on dolomitic white marble. The performance of the laser techniques is compared to common cleaning methods on the same samples, namely pressurized water and chemical treatments. The degree of cleaning achieved with each technique is assessed by means of colorimetric measurements and X-ray microfluorescence. Eventual morphological changes induced on the marble substrate are monitored with optical and electronic microscopy. It is found that UV pulsed laser ablation at 266 nm manages to clean all the stains except the cutting-edge ink, although some degree of surface erosion is produced. The IR laser pulses at 1064 nm can remove surface deposits and black spray acceptably, but a yellowing is observed on the stone surface after treatment. An economic evaluation shows that pulsed laser cleaning techniques are advantageous for the rapid cleaning of small or inaccessible surface areas, although their extensive application becomes expensive due to the long operating times required.

  7. Comparative study of pulsed laser cleaning applied to weathered marble surfaces

    International Nuclear Information System (INIS)

    Ortiz, P.; Antúnez, V.; Ortiz, R.; Martín, J.M.; Gómez, M.A.; Hortal, A.R.; Martínez-Haya, B.

    2013-01-01

    The removal of unwanted matter from surface stones is a demanding task in the conservation of cultural heritage. This paper investigates the effectiveness of near-infrared (IR) and ultraviolet (UV) laser pulses for the cleaning of surface deposits, iron oxide stains and different types of graffiti (black, red and green sprays and markers, and black cutting-edge ink) on dolomitic white marble. The performance of the laser techniques is compared to common cleaning methods on the same samples, namely pressurized water and chemical treatments. The degree of cleaning achieved with each technique is assessed by means of colorimetric measurements and X-ray microfluorescence. Eventual morphological changes induced on the marble substrate are monitored with optical and electronic microscopy. It is found that UV pulsed laser ablation at 266 nm manages to clean all the stains except the cutting-edge ink, although some degree of surface erosion is produced. The IR laser pulses at 1064 nm can remove surface deposits and black spray acceptably, but a yellowing is observed on the stone surface after treatment. An economic evaluation shows that pulsed laser cleaning techniques are advantageous for the rapid cleaning of small or inaccessible surface areas, although their extensive application becomes expensive due to the long operating times required.

  8. Comparative study of pulsed laser cleaning applied to weathered marble surfaces

    Science.gov (United States)

    Ortiz, P.; Antúnez, V.; Ortiz, R.; Martín, J. M.; Gómez, M. A.; Hortal, A. R.; Martínez-Haya, B.

    2013-10-01

    The removal of unwanted matter from surface stones is a demanding task in the conservation of cultural heritage. This paper investigates the effectiveness of near-infrared (IR) and ultraviolet (UV) laser pulses for the cleaning of surface deposits, iron oxide stains and different types of graffiti (black, red and green sprays and markers, and black cutting-edge ink) on dolomitic white marble. The performance of the laser techniques is compared to common cleaning methods on the same samples, namely pressurized water and chemical treatments. The degree of cleaning achieved with each technique is assessed by means of colorimetric measurements and X-ray microfluorescence. Eventual morphological changes induced on the marble substrate are monitored with optical and electronic microscopy. It is found that UV pulsed laser ablation at 266 nm manages to clean all the stains except the cutting-edge ink, although some degree of surface erosion is produced. The IR laser pulses at 1064 nm can remove surface deposits and black spray acceptably, but a yellowing is observed on the stone surface after treatment. An economic evaluation shows that pulsed laser cleaning techniques are advantageous for the rapid cleaning of small or inaccessible surface areas, although their extensive application becomes expensive due to the long operating times required.

  9. DEGRADATION BY PULSED CORONA DISCHARGES: STUDY ON THE POSSIBLE CHEMICAL DEGRADATION PATHWAY FOR DICLOFENAC

    OpenAIRE

    TORRES-GODOY, CYNTHIA

    2012-01-01

    The remo val of hazardous organic pollutants such as polychlorinated biphenyls (PCB's), polycyclic aromatic hydrocarbons (benzopyrene, dibenzoanthracene), pesticides (DDT, lindane), and pharmaceutical products ( diclofenac, ibuprofen, carbamazepine) from waste water is a growing concem in environmental science and technology. Therefore, innovative methods for water remediation in removing contaminants from waste sites need to be examined. This work explores the use of Pulsed Corona Disc...

  10. A pulse radiolysis study of the formation and reactions of reduced metal EDTA complexes

    International Nuclear Information System (INIS)

    Buitenhuis, R.

    1977-01-01

    The construction of a computerized pulse radiolysis system with available means appropriate for the wavelength interval between 300 and 1000 nm is described. The investigation of the radiolysis of aqueous solutions of EDTA complexes in the presence of alcohols is discussed

  11. Ultrafast electron field emission from gold resonant antennas studied by two terahertz pulse experiments

    DEFF Research Database (Denmark)

    Iwaszczuk, Krzysztof; Zalkovskij, Maksim; Strikwerda, Andrew C.

    2015-01-01

    Summary form only given. Ultrafast electron field emission from gold resonant antennas induced by strong terahertz (THz) transient is investigated using two THz pulse experiments. It is shown that UV emission from nitrogen plasma generated by liberated electrons is a good indication of the local...

  12. Tar removal from biomass derived fuel gas by pulsed corona discharges: chemical kinetic study II

    NARCIS (Netherlands)

    Nair, S.A.; Yan, K.; Pemen, A.J.M.; Heesch, van E.J.M.; Ptasinski, K.J.; Drinkenburg, A.A.H.

    2005-01-01

    Tar (heavy hydrocarbon or poly aromatic hydrocarbon (PAH)) removal from biomass derived fuel gas is one of the biggest obstacles in its utilization for power generation. We have investigated pulsed corona as a method for tar removal. Our previous experimental results indicate the energy consumption

  13. Study of the interaction between heavy ions and integrated circuits using a pulsed laser beam

    International Nuclear Information System (INIS)

    Lewis, D.; Fouillat, P.; Pouget, V.; Lapuyade, H.

    2002-01-01

    A new pulsed laser beam equipment dedicated to the characterization of integrated circuit is presented. Using ultra-short laser pulses is a convenient way to simulate experimentally the spatial environment of integrated circuits when interactions with heavy ions occur. This experimental set-up can be considered as a complementary tool for particle accelerators to evaluate the hardness assurance of integrated circuits for space applications. These particles generate temporally electrical disturbance called Single Event Effect (SEE). The theoretical approach of an equivalence between heavy ions and a laser pulses is discussed. The experimental set-up and some relevant operational methodologies are presented. Experimental results demonstrate that the induced electrical responses due to an heavy ion or a laser pulse are quite similar. Some sensitivity mappings of integrated circuits provided by this test bench illustrate the capabilities and the limitations of this laser-based technique. Contrary to the particle accelerators, it provides useful information concerning the spatial and temporal dependences of SEE mechanisms. (authors)

  14. Using a Force Probe to Study Transverse Pulses and Reflections on a Plucked Elastic Cord

    Science.gov (United States)

    Hamalainen, Ari; Abbott, David

    2010-01-01

    Before the advent of microcomputer-based labware (MBL), "time-of-flight" measurements for the speed of a transverse pulse on a string required elegant apparatus. This paper describes how to use an off-the-shelf MBL force sensor and a computer to perform the measurement. The data shown in this paper were collected using Vernier Software's wireless…

  15. Reactivity of OH and O– with aqueous methyl viologen studied by pulse radiolysis

    DEFF Research Database (Denmark)

    Solar, Sonja; Solar, Wolfgang; Getoff, Nikola

    1985-01-01

    The behaviour of aqueous MV2+ towards oxidizing radicals (OH and O–) has been investigated in the pH range from 6 to 14 by means of pulse radiolysis. A semi-linear optimization method was applied for resolving the complex reaction mechanism. In the pH range from 6 to 8 the rate constant for attac...

  16. A portable high-field pulsed-magnet system for single-crystal x-ray scattering studies

    International Nuclear Information System (INIS)

    Islam, Zahirul; Lang, Jonathan C.; Ruff, Jacob P. C.; Ross, Kathryn A.; Gaulin, Bruce D.; Nojiri, Hiroyuki; Matsuda, Yasuhiro H.; Qu Zhe

    2009-01-01

    We present a portable pulsed-magnet system for x-ray studies of materials in high magnetic fields (up to 30 T). The apparatus consists of a split-pair of minicoils cooled on a closed-cycle cryostat, which is used for x-ray diffraction studies with applied field normal to the scattering plane. A second independent closed-cycle cryostat is used for cooling the sample to near liquid helium temperatures. Pulsed magnetic fields (∼1 ms in total duration) are generated by discharging a configurable capacitor bank into the magnet coils. Time-resolved scattering data are collected using a combination of a fast single-photon counting detector, a multichannel scaler, and a high-resolution digital storage oscilloscope. The capabilities of this instrument are used to study a geometrically frustrated system revealing strong magnetostrictive effects in the spin-liquid state.

  17. Carotid-femoral pulse wave velocity in a healthy adult sample: The ELSA-Brasil study.

    Science.gov (United States)

    Baldo, Marcelo Perim; Cunha, Roberto S; Molina, Maria Del Carmen B; Chór, Dora; Griep, Rosane H; Duncan, Bruce B; Schmidt, Maria Inês; Ribeiro, Antonio L P; Barreto, Sandhi M; Lotufo, Paulo A; Bensenor, Isabela M; Pereira, Alexandre C; Mill, José Geraldo

    2018-01-15

    Aging declines essential physiological functions, and the vascular system is strongly affected by artery stiffening. We intended to define the age- and sex-specific reference values for carotid-to-femoral pulse wave velocity (cf-PWV) in a sample free of major risk factors. The ELSA-Brasil study enrolled 15,105 participants aged 35-74years. The healthy sample was achieved by excluding diabetics, those over the optimal and normal blood pressure levels, body mass index ≤18.5 or ≥25kg/m 2 , current and former smokers, and those with self-report of previous cardiovascular disease. After exclusions, the sample consisted of 2158 healthy adults (1412 women). Although cf-PWV predictors were similar between sex (age, mean arterial pressure (MAP) and heart rate), cf-PWV was higher in men (8.74±1.15 vs. 8.31±1.13m/s; adjusted for age and MAP, PELSA-Brasil population (n=15,105) increased by twice the age-related slope of cf-PWV growth, regardless of sex (0.0919±0.182 vs. 0.0504±0.153m/s per year for men, 0.0960±0.173 vs. 0.0606±0.139m/s per year for women). cf-PWV is different between men and women and even in an optimal and normal range of MAP and free of other classical risk factors for arterial stiffness, reference values for cf-PWV should take into account MAP levels. Also, the presence of major risk factors in the general population doubles the age-related rise in cf-PWV. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. One-electron transfer equilibria and redox potentials of radicals studied by pulse radiolysis

    International Nuclear Information System (INIS)

    Meisel, D.; Czapski, G.

    1975-01-01

    The pulse radiolysis technique is utilized for measurements of the equilibrium constants for electron transfer between the durosemiquinone radical anion and oxygen, menadione, and indigodisulfonate. These equilibrium constants are in turn used for calculations of one-electron redox potentials for these systems. Each of these equilibrium constants was determined experimentally and independently and found to be self-consistent. Only for the reactions of the semiquinone radical ions with oxygen could the electron transfer reaction be followed directly. For the reactions between the various quinone-semiquinone systems substantial indirect evidence is presented that these equilibria are achieved rapidly. In those cases equilibrium constants were determined from studies of the effect of quinone concentrations on the relative yields of the semiquinones. A method for distinguishing between kinetic competition and equilibrium is outlined and its usefulness is emphasized. The DQ parallel DQ - (DQ = duroquinone) and IDS parallel IDS - (IDS = indigodisulfonate) systems were employed as reference couples as the redox potentials for those systems are either available in the literature (IDS parallel IDS - ) or may be calculated from available data (DQ parallel DQ - ). Taking E 7 1 , the redox potential for the first one-electron reduction step at pH 7, of DQ parallel DQ - as -0.235 V or of IDS parallelIDS - as -0.247 V both yield E 7 1 = -0.325 V for the O 2 parallel O 2 - system (1 atm of O 2 ) and E 2 1 = -0.20 V for the menadione system. (U.S.)

  19. Electron microscopy studies of octa-calcium phosphate thin films obtained by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Iliescu, Monica; Nelea, V.; Werckmann, J.; Mihailescu, I.N.; Socol, G.; Bigi, Adriana; Bracci, Barbara

    2004-04-01

    Octa-calcium phosphate (OCP), Ca{sub 8}(HPO{sub 4}){sub 2}(PO{sub 4}){sub 4}{center_dot}5H{sub 2}O, is present as transient compound in the precipitation of hydroxyapatite (HA) and biological apatites. Because of these characteristics, OCP plays a crucial role in the in-vivo mineralization of human bones and teeth. The use of OCP in developing new generations of bone prosthesis stands therefore for an innovative challenge. This paper reports studies of OCP structures grown in the form of thin films by pulsed laser deposition (PLD) with emphasis on electron microscopy investigations. OCP films were grown on etched Ti substrates, using an UV KrF* excimer laser source ({lambda}=248 nm, {tau}{>=}20 ns). Films were deposited in low-pressure (50 Pa) water vapors environment on substrates heated at 20-180 deg. C. We performed annealing treatments in water vapors and ambient pressure at substrate temperatures identical to those used during deposition. Comprehensive structural and morphological investigations were carried out with different based-electron microscopy procedures. Grazing incidence X-ray diffraction (GIXRD) and white light confocal microscopy were also applied to characterize the films. Ca/P atomic ratio of films was determined by energy dispersive X-ray spectrometry, electron energy loss spectroscopy and X-ray photoelectron spectroscopy. The obtained films generally exhibit an amorphous structure, as evidenced by GIXRD. Nevertheless, cross-section transmission electron microscopy investigations provide supplementary information about the film characteristics and material crystallization in small domains. OCP nanoparticles coalesce and grow perpendicular to the substrate in a tree-like structure, comparable to a coral reef.

  20. Pulse radiolysis study of supercritical water-G-value measurement up to 450 degree C

    International Nuclear Information System (INIS)

    Katsumura, Y.

    2006-01-01

    It is widely recognized that the understanding of water radiolysis at elevated temperatures is inevitably important in the field of water chemistry in light water reactors because water radiolysis is closely related to many subjects such as hydrogen water chemistry (H 2 injection), SCC (stress corrosion cracking), dose accumulation and so on. This situation would also be applied to the future reactor using supercritical water (>374 C, 22.1MPa) as a coolant, so called supercritical water-cooled reactor (SCWR). Therefore, it is important to investigate water radiolysis of supercritical water. In 1989 Prof. Oka, University of Tokyo, proposed the SCWR as a future reactor and done much design study. This reactor has many advantages such as high energy efficiency, applicability of experience accumulated in light water reactors and supercritical fissile plant, and compact structure. In 2002 the Department of Energy in USA has selected the SCWR as one of the six Generation IV reactors and fundamental research has started in different countries as a national or an international project. In the present research G-values of water radiolysis have been measured by using a pulse radiolysis method up to 450 degree C to obtain the fundamental data relevant to the development of the SCWR. In supercritical water, the pressure controls the density of water easily and it was found that the G-values are strongly dependent not only on temperature but also on density in supercritical water. After presentation of experimental method and its difficulties, temperature and density dependent G-values of water decomposition products in supercritical water would be summarized. (authors)

  1. Pulsed NMR studies of crosslinking and entanglements in high molecular weight linear polydimethylsiloxanes

    International Nuclear Information System (INIS)

    Folland, R.; Charlesby, A.

    1977-01-01

    Pulsed NMR studies of proton spin relaxation are used to investigate both radiation-induced cross linking and entanglements in three high molecular weight linear polydimethylsiloxanes (Msub(w) = 26,000, 63,000 and 110,000). Particular emphasis is placed on the spin-spin relaxation since this is determined by the slower relative translational motions of the polymer chains and hence profoundly affected by the presence of intermolecular couplings such as crosslinks or entanglements. The spin-lattice relaxation times, T 1 , are determined by the fast anisotropic chain rotations and are rather insensitive to such intermolecular couplings. The spin-spin relaxation in these materials is represented by a double exponential decay involving two time constants, Tsub(2S) and Tsub(2L). The shorter component, Tsub(2S), is attributed to network material, which may be either of a dynamic form arising from temporary entanglements or of a permanent nature due to crosslinks. The concentration of entanglements depends on the initial molecular weight of the sample whereas the concentration of crosslinks is a function of the radiation dose. The longer component, Tsub(2L), is attributed to the non-network molecules. On the time scale of the NMR measurements the entanglements are shown to act in the same way as crosslinks. The variation of the relative proportions of network and non-network material with dose is shown to be accounted for by using standard gelation theory when allowance is made for the initial effective crosslink density due to entanglements. The analysis provides a value for the average molecular weight per entanglement point of 27,000 +- 1000 which is consistent with the critical molecular weight for entanglements of 29,000. The dependences of Tsub(2S) and Tsub(2L) on dose and molecular weight are also discussed in terms of the molecular motion. (author)

  2. Study of ultra-high gradient wakefield excitation by intense ultrashort laser pulses in plasma

    International Nuclear Information System (INIS)

    Kotaki, Hideyuki

    2002-12-01

    We investigate a mechanism of nonlinear phenomena in laser-plasma interaction, a laser wakefield excited by intense laser pulses, and the possibility of generating an intense bright electron source by an intense laser pulse. We need to understand and further employ some of these phenomena for our purposes. We measure self-focusing, filamentation, and the anomalous blueshift of the laser pulse. The ionization of gas with the self-focusing causes a broad continuous spectrum with blueshift. The normal blueshift depends on the laser intensity and the plasma density. We, however, have found different phenomenon. The laser spectrum shifts to fixed wavelength independent of the laser power and gas pressure above some critical power. We call the phenomenon 'anomalous blueshift'. The results are explained by the formation of filaments. An intense laser pulse can excite a laser wakefield in plasma. The coherent wakefield excited by 2 TW, 50 fs laser pulses in a gas-jet plasma around 10 18 cm -3 is measured with a time-resolved frequency domain interferometer (FDI). The density distribution of the helium gas is measured with a time-resolved Mach-Zehnder interferometer to search for the optimum laser focus position and timing in the gas-jet. The results show an accelerating wakefield excitation of 20 GeV/m with good coherency, which is useful for ultrahigh gradient particle acceleration in a compact system. This is the first time-resolved measurement of laser wakefield excitation in a gas-jet plasma. The experimental results are compared with a Particle-in-Cell (PIC) simulation. The pump-probe interferometer system of FDI and the anomalous blueshift will be modified to the optical injection system as a relativistic electron beam injector. In 1D PIC simulation we obtain the results of high quality intense electron beam acceleration. These results illuminate the possibility of a high energy and a high quality electron beam acceleration. (author)

  3. Advanced numerical studies of the neutralized drift compression of intense ion beam pulses

    Directory of Open Access Journals (Sweden)

    Adam B. Sefkow

    2007-10-01

    Full Text Available Longitudinal bunch compression of intense ion beams for warm dense matter and heavy ion fusion applications occurs by imposing an axial velocity tilt onto an ion beam across the acceleration gap of a linear induction accelerator, and subsequently allowing the beam to drift through plasma in order to neutralize its space-charge and current as the pulse compresses. The detailed physics and implications of acceleration gap effects and focusing aberration on optimum longitudinal compression are quantitatively reviewed using particle-in-cell simulations, showing their dependence on many system parameters. Finite-size gap effects are shown to result in compression reduction, due to an increase in the effective longitudinal temperature imparted to the beam, and a decrease in intended fractional tilt. Sensitivity of the focal plane quality to initial longitudinal beam temperature is explored, where slower particles are shown to experience increased levels of focusing aberration compared to faster particles. A plateau effect in axial compression is shown to occur for larger initial pulse lengths, where the increases in focusing aberration over the longer drift lengths involved dominate the increases in relative compression, indicating a trade-off between current compression and pulse duration. The dependence on intended fractional tilt is also discussed and agrees well with theory. A balance between longer initial pulse lengths and larger tilts is suggested, since both increase the current compression, but have opposite effects on the final pulse length, drift length, and amount of longitudinal focusing aberration. Quantitative examples are outlined that explore the sensitive dependence of compression on the initial kinetic energy and thermal distribution of the beam particles. Simultaneous transverse and longitudinal current density compression can be achieved in the laboratory using a strong final-focus solenoid, and simulations addressing the effects

  4. Experimental Study of Direct Laser Deposition of Ti-6Al-4V and Inconel 718 by Using Pulsed Parameters

    Directory of Open Access Journals (Sweden)

    Kamran Shah

    2014-01-01

    Full Text Available Laser direct metal deposition (LDMD has developed from a prototyping to a single metal manufacturing tool. Its potential for creating multimaterial and functionally graded structures is now beginning to be explored. This work is a first part of a study in which a single layer of Inconel 718 is deposited on Ti-6Al-4V substrate. Single layer tracks were built at a range of powder mass flow rates using a coaxial nozzle and 1.5 kW diode laser operating in both continuous and pulsed beam modes. This part of the study focused on the experimental findings during the deposition of Inconel 718 powder on Ti-6Al-4V substrate. Scanning electron microscopy (SEM and X-ray diffraction analysis were performed for characterization and phase identification. Residual stress measurement had been carried out to ascertain the effects of laser pulse parameters on the crack development during the deposition process.

  5. Morphology and structural studies of WO_3 films deposited on SrTiO_3 by pulsed laser deposition

    International Nuclear Information System (INIS)

    Kalhori, Hossein; Porter, Stephen B.; Esmaeily, Amir Sajjad; Coey, Michael; Ranjbar, Mehdi; Salamati, Hadi

    2016-01-01

    Highlights: • Highly oriented WO_3 stoichiometric films were determined using pulsed laser deposition method. • Effective parameters on thin films including temperature, oxygen partial pressure and laser energy fluency was studied. • A phase transition was observed in WO_3 films at 700 °C from monoclinic to tetragonal. - Abstract: WO_3 films have been grown by pulsed laser deposition on SrTiO_3 (001) substrates. The effects of substrate temperature, oxygen partial pressure and energy fluence of the laser beam on the physical properties of the films were studied. Reflection high-energy electron diffraction (RHEED) patterns during and after growth were used to determine the surface structure and morphology. The chemical composition and crystalline phases were obtained by XPS and XRD respectively. AFM results showed that the roughness and skewness of the films depend on the substrate temperature during deposition. Optimal conditions were determined for the growth of the highly oriented films.

  6. Pulse induction heating

    Energy Technology Data Exchange (ETDEWEB)

    Vasiliev, A S; Kachanov, B Y; Kogan, B V

    1993-12-31

    Induction heating and three types of pulse processes were studied. It was found that in pulse processes the frequency and pulse duration of heat treatments do not remain constant. High frequency pulse heat treatments can be used on sprayed coatings; such treatments will result in stronger surfaces with no cracks. For induction hardening, the rate of specific power was 1 to 1.5 kW/sq.cm, for forging it was 0.2 to 0.3 kW/sq.cm and for melting it was 0.05 to 0.1 kW/sq.cm. The application of pulse heating will result in higher rates of specific power.

  7. Intense pulsed light, near infrared pulsed light, and fractional laser combination therapy for skin rejuvenation in Asian subjects: a prospective multi-center study in China.

    Science.gov (United States)

    Tao, Li; Wu, Jiaqiang; Qian, Hui; Lu, Zhong; Li, Yuanhong; Wang, Weizhen; Zhao, Xiaozhong; Tu, Ping; Yin, Rui; Xiang, Leihong

    2015-09-01

    Ablative skin rejuvenation therapies have limitations for Asian people, including post-inflammatory hyperpigmentation and long down time. Non-ablative lasers are safer but have limited efficacy. This study is to investigate the safety and efficacy of a combination therapy consisting of intense pulsed light (IPL), near infrared (NIR) light, and fractional erbium YAG (Er:YAG) laser for skin rejuvenation in Asian people. This study recruited 113 subjects from six sites in China. Subjects were randomly assigned to a full-face group, who received combination therapy, and split-face groups, in which one half of the face received combination therapy and the other half received IPL monotherapy. Each subject received five treatment sessions during a period of 90 days. Subjects were followed up at 1 and 3 months post last treatment. Three months after last treatment, the full-face group (n = 57) had a global improvement rate of 29 % and 29 % for wrinkles, 32 % for skin texture, 33 % for pigment spots, 28 % for pore size, respectively. For patients in the split-face groups (n = 54), monotherapy side had a global improvement rate of 23 % and 20 % for wrinkles, 27 % for skin texture, 25 % for pigment spots, 25 % for pore size, respectively. Both combination therapy and monotherapy resulted in significant improvements at the follow-up visits compared to baseline (P < 0.001). Combination therapy showed significantly greater improvements compared to monotherapy at two follow-up visits (P < 0.05). Combination therapy is a safe and more effective strategy than IPL monotherapy for skin rejuvenation in Asian people.

  8. Pulse radiolysis study on solvated electrons in ionic liquid with controlling water content

    International Nuclear Information System (INIS)

    Yang Jinfeng; Kondoh, T.; Yoshida, Y.; Nagaishi, R.

    2006-01-01

    Room-temperature ionic liquids, which are nonvolatile and nonflammable, have been proposed as 'green solvents' for new applications in chemical synthesis, separation chemistry, electrochemistry and other areas. In the separation chemistry, the hydrophobic ionic liquids have been practically expected to be alternative to traditional organic solvents for solvent extraction of 4f and 5f elements from the viewpoints of the immiscibility in water, especially in the spent nuclear fuel reprocessing. However, the chemical reaction or kinetics studies are important to apply the ionic liquids for various processes. To understand the effects of ionic liquids on chemical reactions, pulse radiolysis studies of ionic liquid have been carried out on nanosecond scale by using a 27 MeV electron beam and an analyzing light source of xenon lamp. In the experiment, a hydrophobic ionic liquid of diethylmethyl(2-methoxy)ammonium-bis(trifluoromethanesulfonyl)imide (DEMMA-TFSI) salt was used. The ionic liquid of DEMMA-TFSI was prepared by reacting equimolar amounts of diethylmethyl(2-methoxy)ammonium chloride (C 10 H 20 F 6 N 2 O 5 S 2 Cl, >98%, Nisshinbo) with lithium bis(trifluoromethanesulfonyl)imide (LiN(SO 2 CF 3 ) 2 , SynQuest Labs., Inc.) in aqueous solutions at room temperature. The ionic liquid was separated from the aqueous phase, purified by repeated extractions with water to LiCl and excess reagent, and finally dried at 110 degree C under vacuum. The transient absorptions of the ionic liquid were measured at wavelengths from 350 to 1400 nm, in which two photodiodes of silicon ( 1000 nm) were used. The spectrum of solvated electrons in the ionic liquid of DEMMA-TFSI was obtained with an absorption peak of 1060 nm and a wide bandwidth of about 600 nm (FWHM). The decay constant of the solvated electrons in the ionic liquid was 1.54 x 10 7 s -1 , which is independent on the wavelength. The absorption peak of the spectrum was blue-shifted from 1060 to 780 nm with increasing water

  9. Effectiveness of Intense Pulsed Light treatment in solar lentigo: a retrospective study

    Directory of Open Access Journals (Sweden)

    İlgen Ertam

    2014-03-01

    Full Text Available Intense Pulsed Light (IPL; is a light system of 500-1200 nm wavelength which is used for the treatment of hair removal, hyperpigmentation, non-ablative skin resurfacing and superficial vascular lesions. The mechanism of action is thought to be the focal epidermal coagulation due to selective photothermolysis in the epidermal keratinocytes and melanocytes. A variety of laser systems can be used in the treatment of lsolar entigo. The aim of this study is to investigate the effectiveness of IPL in solar lentigo. Materials and Methods: The archives of Cosmetology Unit retrospectively reviewed for the patients with the diagnosis of solar lentigo from March 2007 to November 2010. There were 139 files of patients who were diagnosed as solar lentigo clinically and dermoscopically and treated by IPL (L900 a & m IPL. Informed consent was taken from all patients. Among them, 42 patients who had come to controls regularly and had photographed before and after treatment included into the study. Results: A total of 52 lesions of 42 female and 1 male patient included into the study. Patients’ mean age was 42±9.6 years, ranging between 33 to 88. Of the lesions, 27 lesions(51.9% were on cheek, 7 lesions (13.5% were on zygoma, 6 lesions (11.5% were on chin, 4 lesions (7.7% were on hands, 4 lesions (7.7% were on forehead, 2 lesions(3.8% were on nose, 2 lesions (3.8% were on forearm. The mean number of sessions was 3.28 ranging between 1 and 7. After treatment, improvement was over 75% in 57,7% lesions, 50-75% in 17.3% of the lesions, 25-50% in 17.3% of the lesions, under 25% in 7.7% of the lesions. Conclusion: According to the results of our work, IPL can be accepted as an effective, cheap and safety method in terms of its side effects in treatment of solar lentigo.

  10. Effects of energy, distance and orientation on electron transfer rates studied by pulse radiolysis in organic media

    International Nuclear Information System (INIS)

    Miller, J.R.

    1987-01-01

    In the past few years the methods of radiation chemistry in organic media have made an enormous change in how we view electron transfer processes, as these media have proved the most useful for studying long distance electron transfer between molecules. This paper briefly summarizes a few of the aspects of this area and discusses some of the attributes and limitations of radiation tehniques, particularly pulse radiolysis, in organic solvents. 14 refs., 2 figs

  11. A Study of Polycrystalline Silicon Damage Features Based on Nanosecond Pulse Laser Irradiation with Different Wavelength Effects

    OpenAIRE

    Xu, Jiangmin; Chen, Chao; Zhang, Tengfei; Han, Zhenchun

    2017-01-01

    Based on PVDF (piezoelectric sensing techniques), this paper attempts to study the propagation law of shock waves in brittle materials during the process of three-wavelength laser irradiation of polysilicon, and discusses the formation mechanism of thermal shock failure. The experimental results show that the vapor pressure effect and the plasma pressure effect in the process of pulsed laser irradiation lead to the splashing of high temperature and high density melt. With the decrease of the ...

  12. Time-resolved studies of ultrarapid solidification of highly undercooled molten silicon formed by pulsed laser irradiation

    International Nuclear Information System (INIS)

    Lowndes, D.H.; Jellison, G.E. Jr.; Wood, R.F.; Carpenter, R.

    1984-01-01

    This paper reports new results of nanosecond-resolution time-resolved optical reflectivity measurements, during pulsed excimer (KrF, 248 nm) laser irradiation of Si-implanted amorphous (a) silicon layers, which, together with model calculations and post-irradiation TEM measurements, have allowed us to study both the transformation of a-Si to a highly undercooled liquid (l) phase and the subsequent ultrarapid solidification process

  13. A study of two kinds of electromagnetic pulse antennas with a continuous resistive loading using the FDTD method

    International Nuclear Information System (INIS)

    Mao Congguang; Zhou Hui

    2003-01-01

    The cylindrical and conical monopole antenna with a continuous resistive loading is considered as a radiator in the experiments of the electromagnetic pulse compatibility. The various principle of the resistive loading is discussed in details and the characters of the antennas are studied using the Finite-Difference Time-Domain (FDTD) method. The key techniques of the calculating are presented. The results are in good agreement with the documents and the theory

  14. Pulse pile-up IV

    International Nuclear Information System (INIS)

    Wilkinson, D.H.

    1991-05-01

    The study of pulse pile-up is extended from the case of unipolar pulses, for which ruin theory is an excellent approximation, to the case of bipolar pulses for which ruin theory is not applicable to the effect of the back-kicks in reducing the pile-up: an appropriate solution is presented. (Author) 3 refs., 11 figs

  15. Study on the mode-transition of nanosecond-pulsed dielectric barrier discharge between uniform and filamentary by controlling pressures and pulse repetition frequencies

    Science.gov (United States)

    Yu, Sizhe; Lu, Xinpei

    2016-09-01

    We investigate the temporally resolved evolution of the nanosecond pulsed dielectric barrier discharge (DBD) in a moderate 6mm gap under various pressures and pulse repetition frequencies (PRFs) by intensified charge-coupled device (ICCD) images, using synthetic air and its components oxygen and nitrogen. It is found that the pressures are very different when the DBD mode transits between uniform and filamentary in air, oxygen, and nitrogen. The PRFs can also obviously affect the mode-transition. The transition mechanism in the pulsed DBD is not Townsend-to-streamer, which is dominant in the traditional alternating-voltage DBDs. The pulsed DBD in a uniform mode develops in the form of plane ionization wave, due to overlap of primary avalanches, while the increase in pressure disturbs the overlap and DBD develops in streamer instead, corresponding to the filamentary mode. Increasing the initiatory electron density by pre-ionization methods may contribute to discharge uniformity at higher pressures. We also find that the dependence of uniformity upon PRF is non-monotonic.

  16. Study of novel plasma devices generated by high power lasers coupled with a micro-pulse power technology

    International Nuclear Information System (INIS)

    Nishida, A; Chen, Z L; Jin, Z; Kondo, K; Nakagawa, M; Kodama, R; Arima, H; Yoneda, H

    2008-01-01

    The authors have proposed introducing a micro pulse power technology in high power laser plasma experiments to boost up the return current, resulting in efficiently guiding of energetic electrons. High current pulse power generators with a pulse laser trigger system generate high-density plasma that is well conductor. To efficiently guiding by using a micro pulse power, we estimated parameter of a micro pulse power system that is voltage of rise time, current, charging voltage and capacitance

  17. A study on matrix assisted pulsed evaporation (MAPLE) of organic materials

    DEFF Research Database (Denmark)

    Matei, Andreea; Canulescu, Stela; Constantinescu, Catalin

    2012-01-01

    Organic films can be produced either by MAPLE or directly by PLD (Pulsed laser deposition). For a reasonable deposition rate of ng/cm2 per pulse for film production by MAPLE a fluence of 1-1.5 J/cm2 is required at the laser wavelength of 355 nm, while the fluence can be considerably lower at 248 nm....... At high fluence the deposition rate of proteins by MAPLE seems to decrease. The surface roughness is still an issue, but at low fluence it seems to be acceptable. The fragmentation rate increases with fluence, and seems to be less pronounced for MAPLE than for PLD. Also this issue is not yet resolved....

  18. Pulsed-field gradient nuclear magnetic resonance study of transport properties of fluid catalytic cracking catalysts

    Czech Academy of Sciences Publication Activity Database

    Kortunov, P.; Vasenkov, S.; Kärger, J.; Fé Elía, M.; Perez, M.; Stöcker, M.; Papadopoulos, G. K.; Theodorou, D.; Drescher, B.; McElhiney, G.; Bernauer, B.; Krystl, V.; Kočiřík, Milan; Zikánová, Arlette; Jirglová, Hana; Berger, C.; Gläser, R.; Weitkamp, J.; Hansen, E. W.

    2005-01-01

    Roč. 23, č. 2 (2005), s. 233-237 ISSN 0730-725X Grant - others:TROCAT project - European Community(DE) G5RD-CT-2001-00520 Institutional research plan: CEZ:AV0Z40400503 Keywords : pulsed-field gradient * nuclear magnetic resonance * fluid catalytic cracking catalyst Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.361, year: 2005

  19. A study of trapped ion dynamics by photon-correlation and pulse-probe techniques

    International Nuclear Information System (INIS)

    Rink, J.; Dholakia, K.; Zs, G.; Horvath, K.; Hernandez-Pozos, J. L.; Power, W.; Segal, D. M.; Thompson, R. C.; Walker, T.

    1995-01-01

    We demonstrate non-evasive methods for observing ion and ion cloud oscillation frequencies in a quadrupole ion trap. These trap resonances are measured for small clouds using a photon correlation technique. For large clouds the rotation frequency can be detected with the help of an additional pulsed probe laser. We show applications of the photon correlation method such as estimating the dynamic properties of a combined trap and detecting ion crystals

  20. Radiolysis of concentrated solutions. 2. Pulse and #betta#-radiolysis studies of direct and indirect effects in lithium iodide solutions

    International Nuclear Information System (INIS)

    Hadjadj, A.; Julien, R.; Pucheault, J.; Ferradini, C.; Hickel, B.

    1982-01-01

    In the preceding study of the radiolysis of concentrated aqueous LiCl solutions, one of the hypotheses used to explain the apparent inefficacy of Cl 2- formation by the direct effect was that molecular chlorine, not detectable by spectrophotometry, could be formed during the early stages of water radiolysis. Such an hypothesis is confirmed here for pulse and #betta#-radiolysis of concentrated aqueous neutral LiI solutions. Indeed, it is shown that, 10 ns after the pulse, molecular iodine, detected as I 3- , is formed with a yield that increases with the LiI concentration. The experimental results yields values of 4.8 and 7.3 respectively for the indirect and direct effects of total oxidation G/sub I 2- / + 2G/sub I 3- /. This last high value is discussed

  1. Study of thermal response of superconducting NbN meander line by using 20 ps pulse laser

    International Nuclear Information System (INIS)

    Miki, Shigehito; Fujiwara, Daisuke; Simakage, Hisashi; Kawakami, Akira; Wang Zhen; Satoh, Kazuo; Yotsuya, Tsutomu; Ishida, Takekazu

    2005-01-01

    The thermal response of a superconducting NbN thin-film meander line was studied by irradiating with a 20 ps pulse laser. A 10 nm-thick NbN thin film was prepared by dc magnetron sputtering and then processed to fabricate a 3 μm-wide, 125.5 mm-long meander line. The device was placed in a 4 K refrigerator, and the bias temperature was kept below the critical temperature T c . The end of an optical fiber was fixed at the front of a meander line, which was then directly irradiated by using the 20 ps pulse laser. The output voltage was observed with a digital oscilloscope and a low-noise amplifier. The output signals of the thermal response were clearly observed

  2. Description of design and operating procedures of small scale pulsed columns for experimental study on extraction process under abnormal conditions

    International Nuclear Information System (INIS)

    Wakamatsu, Sachio; Sato, Makoto; Kubo, Nobuo; Sakurai, Satoshi; Ami, Norio

    1990-09-01

    To study transient phenomena in a pulsed column co-decontamination process under abnormal conditions, a pair of small scale pulsed columns (effective extraction section; I.D: 25 mm, H.: 2260 mm) for extraction and scrub were installed in the laboratory. An evaporator of aqueous uranium solution was also equipped to reuse concentrated solution as the feed. This report describes several items to have been carefully treated in design, specification and operating procedure of the apparatuses for the experiments. Also described are the procedures for preparation of the feed solutions and treatments of the solutions after the experiments; back-extraction of uranium, diluent washing, alkaline washing and concentration of uranium solution. (author)

  3. Model study of an automatic controller of the IBR-2 pulsed reactor

    International Nuclear Information System (INIS)

    Pepelyshev, Yu.N.; Popov, A.K.

    2007-01-01

    For calculation of power transients in the IBR-2 reactor a special mathematical model of dynamics taking into account the discontinuous jump of reactivity by an automatic controller with the step motor is created. In the model the nonlinear dependence of the energy of power pulse on the reactivity and the influence of warming up of the reactor on the reactivity by means of introduction of a nonlinear feedback 'power-pulse energy - reactivity' are taken into account. With the help of the model the transients of relative deviation of power-pulse energy are calculated at various (random, mixed and regular) reactivity disturbances at the reactor mean power 1.475 MW. It is shown that to improve the quality of processes the choice of such regular values of parameters of the automatic controller is expedient, at which the least effect of smoothing of a signal acting on an automatic controller and the least speed of an automatic controller are provided, and the reduction of efficiency of one step of the automatic controller and introduction of a five-percent dead space are also expedient

  4. Laboratory studies of the behavior of undissolved solids in both pulsed and packed column extraction systems

    International Nuclear Information System (INIS)

    Siemer, D.D.

    1989-01-01

    A substantial fraction of the finely divided undissolved solid material found in nuclear fuel reprocessing dissolver-product solutions is hydrophobic and tends to ''seek'' any organic-aqueous interface existing within countercurrent liquid-liquid extraction systems. While passing through pulsed-type columns this material is swept out of the aqueous phase by the combined surface area of the tiny bubbles of dispersed phase. Because these bubbles have a net velocity towards the end of the column where the nominal interface is located, the solids are swept in that direction too. These solids tend to gather in a three-phase ''crud'' layer at the nominal interface point. At equilibrium, about the same amount breaks off from the crud layer and escapes into the liquid exiting from that end of the column as enters it from the other side. If large enough, the crud layer can even interfere with interface detection and control equipment. In packed-column extraction systems, an additional problem is that feed solids can accumulate within the packing material to the point that the column '' floods'' or even totally plugs. The keys to preventing solids-related problems is the correct choice of interface level, and with packed columns, the addition of a ''pulsing leg'' at the bottom of the column. Pulsing packed column systems not only prevents solids from settling onto packing material but it also increses the number of theoretical stages available for extraction. 3 figs., 2 tabs

  5. Non-invasive aortic systolic pressure and pulse wave velocity estimation in a primary care setting: An in silico study.

    Science.gov (United States)

    Guala, Andrea; Camporeale, Carlo; Ridolfi, Luca; Mesin, Luca

    2017-04-01

    Everyday clinical cardiovascular evaluation is still largely based on brachial systolic and diastolic pressures. However, several clinical studies have demonstrated the higher diagnostic capacities of the aortic pressure, as well as the need to assess the aortic mechanical properties (e.g., by measuring the aortic pulse wave velocity). In order to fill this gap, we propose to exploit a set of easy-to-obtain physical characteristics to estimate the aortic pressure and pulse wave velocity. To this aim, a large population of virtual subjects is created by a validated mathematical model of the cardiovascular system. Quadratic regressive models are then fitted and statistically selected in order to obtain reliable estimations of the aortic pressure and pulse wave velocity starting from the knowledge of the subject age, height, weight, brachial pressure, photoplethysmographic measures and either electrocardiogram or phonocardiogram. The results are very encouraging and foster clinical studies aiming to apply a similar technique to a real population. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

  6. Gold Nanoparticle-Mediated Delivery of Molecules into Primary Human Gingival Fibroblasts Using ns-Laser Pulses: A Pilot Study

    Directory of Open Access Journals (Sweden)

    Judith Krawinkel

    2016-05-01

    Full Text Available Interaction of gold nanoparticles (AuNPs in the vicinity of cells’ membrane with a pulsed laser (λ = 532 nm, τ = 1 ns leads to perforation of the cell membrane, thereby allowing extracellular molecules to diffuse into the cell. The objective of this study was to develop an experimental setting to deliver molecules into primary human gingival fibroblasts (pHFIB-G by using ns-laser pulses interacting with AuNPs (study group. To compare the parameters required for manipulation of pHFIB-G with those needed for cell lines, a canine pleomorphic adenoma cell line (ZMTH3 was used (control group. Non-laser-treated cells incubated with AuNPs and the delivery molecules served as negative control. Laser irradiation (up to 35 mJ/cm2 resulted in a significant proportion of manipulated fibroblasts (up to 85%, compared to non-irradiated cells: p < 0.05, while cell viability (97% was not reduced significantly. pHFIB-G were perforated as efficiently as ZMTH3. No significant decrease of metabolic cell activity was observed up to 72 h after laser treatment. The fibroblasts took up dextrans with molecular weights up to 500 kDa. Interaction of AuNPs and a pulsed laser beam yields a spatially selective technique for manipulation of even primary cells such as pHFIB-G in high throughput.

  7. Study on the cutting quality by rectangular pulse wave of the CO sub 2 laser. CO sub 2 laser no kukei pulse hakei ni yoru setsudan hinshitsu no kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Kanaoka, M. (Mitsubishi Electric Corporation, Tokyo (Japan))

    1992-05-20

    The paper studies effects of laser power parameters on processing quality in cutting metal by the use of rectangular pulse waveform formed by the triaxial cross flow resonator. As a result, the heat affected zone appearing around the kerf expands from the upper part to the lower part, and by increasing pulse peak power the width of the heat affected zone from the central part of board thickness to the lower part lessens. Further, by lowering pulse frequency, the width of the heat affected zone appearing around the kerf from the central part of board thickness to the lower part lessens. Also, by lowering frequency, an energy absortion rate of the workpiece to be processed decreases. Cutting surface roughness is affected by pulse peak power, and the high the peak value is, the better the surface roughness is improved. In addition, the surface roughmess is affected by pulse frequency, and the higher the frequency is, the better the surface roughness is improved. 6 refs., 15 figs.

  8. Biochemical study of human periodontal ligament: preparation of cell attachment materials induced by pulsed electromagnetic fields.

    Science.gov (United States)

    Kim, K T

    1990-09-01

    The periodontium, especially the periodontal ligament and alveolar bone, are tissues constantly subjected to physical stress such as occlusion and mastication. This study was designed to explore the effect of the pulsed electromagnetic fields (PEMF) on the cell attachment and the spread of human periodontal ligament fibroblasts (HPLF) and rat osteoblasts (ROB). PEMF are categorized as one type of mechanical stress. HPLF were obtained by the explantation method described by Saito et al. They were then subcultured in Dulbecco's modified Eagle's medium (D-MEM) and supplemented with 2 mg/ml dialyzed fetal calf serum protein (FCSP), 50 micrograms/ml ascorbic acid and penicillin/streptomycin after trypsinization. ROB were isolated from a two-day-old rat calvaria by the sequential bacterial collagenase digestion method described by Dziak and Brand and were subcultured in D-MEM supplemented with FCSP, ascorbic acid and penicillin/streptomycin. After the confluent HPLF were cultured with serum-free MCDB 107 medium, the quiescent HPLF were exposed with or without PEMF for 24 hr. This was followed by the collection of the control conditioned medium (C-CM) and PEMF exposed conditioned medium (PEMF-CM). The cell attachment assay was performed so that the hydrophobic 24 multiwells were coated with the whole conditioned medium or fractionated conditioned medium by a PO-60K column. After coating, heat inactivated BSA blocked nonspecific sites for cell adhesion, and 3H-TdR labeled HPLF or ROB were cultured on the precoated wells. The activity of cell attachment and spreading was determined by the radioactivity of 3H-TdR using a scintillation counter. The characters of cell attachment factors derived from HPLF were hydrophobic, heat labile and proteolytic enzyme digestible. In addition, the fractionated PEMF-CM enhanced the spreading activity of ROB. PEMF induced the 10 KDa which can enhance the HPLF and ROB spreading. Therefore, the cell attachment and spreading factors secreted by

  9. Study and development of 22 kW peak power fiber coupled short pulse Nd:YAG laser for cleaning applications

    Science.gov (United States)

    Choubey, Ambar; Vishwakarma, S. C.; Vachhani, D. M.; Singh, Ravindra; Misra, Pushkar; Jain, R. K.; Arya, R.; Upadhyaya, B. N.; Oak, S. M.

    2014-11-01

    Free running short pulse Nd:YAG laser of microsecond pulse duration and high peak power has a unique capability to ablate material from the surface without heat propagation into the bulk. Applications of short pulse Nd:YAG lasers include cleaning and restoration of marble, stones, and a variety of metals for conservation. A study on the development of high peak power short pulses from Nd:YAG laser along with its cleaning and conservation applications has been performed. A pulse energy of 1.25 J with 55 μs pulse duration and a maximum peak power of 22 kW has been achieved. Laser beam has an M2 value of ~28 and a pulse-to-pulse stability of ±2.5%. A lower value of M2 means a better beam quality of the laser in multimode operation. A top hat spatial profile of the laser beam was achieved at the exit end of 200 μm core diameter optical fiber, which is desirable for uniform cleaning. This laser system has been evaluated for efficient cleaning of surface contaminations on marble, zircaloy, and inconel materials for conservation with cleaning efficiency as high as 98%. Laser's cleaning quality and efficiency have been analysed by using a microscope, a scanning electron microscope (SEM), and X-ray photon spectroscopy (XPS) measurements.

  10. A BROADBAND RADIO STUDY OF THE AVERAGE PROFILE AND GIANT PULSES FROM PSR B1821-24A

    Energy Technology Data Exchange (ETDEWEB)

    Bilous, A. V. [Department of Astrophysics/IMAPP, Radboud University Nijmegen, P.O. Box 9010, 6500 GL Nijmegen (Netherlands); Pennucci, T. T. [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904 (United States); Demorest, P. [National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States); Ransom, S. M., E-mail: a.bilous@science.ru.nl [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States)

    2015-04-20

    We present the results of a wideband (720–2400 MHz) study of PSR B1821–24A (J1824–2452A, M28A), an energetic millisecond pulsar (MSP) visible in radio, X-rays and γ-rays. In radio, the pulsar has a complex average profile that spans ≳85% of the spin period and exhibits strong evolution with observing frequency. For the first time we measure phase-resolved polarization properties and spectral indices of radio emission throughout almost all of the on-pulse window. We synthesize our findings with high-energy information to compare M28A to other known γ-ray MSPs and to speculate that M28A’s radio emission originates in multiple regions within its magnetosphere (i.e., both in the slot or outer gaps near the light cylinder and at lower altitudes above the polar cap). M28A is one of a handful of pulsars that are known to emit giant radio pulses (GRPs)—short, bright radio pulses of unknown nature. We report a drop in the linear polarization of the average profile in both windows of GRP generation and also a “W”-shaped absorption feature (resembling a double notch), partly overlapping with one of the GRP windows. The GRPs themselves have broadband spectra consisting of multiple patches with Δν/ν ∼ 0.07. Although our time resolution was not sufficient to resolve the GRP structure on the μs scale, we argue that GRPs from this pulsar most closely resemble the GRPs from the main pulse of the Crab pulsar, which consist of a series of narrowband nanoshots.

  11. Performance study of highly efficient 520 W average power long pulse ceramic Nd:YAG rod laser

    Science.gov (United States)

    Choubey, Ambar; Vishwakarma, S. C.; Ali, Sabir; Jain, R. K.; Upadhyaya, B. N.; Oak, S. M.

    2013-10-01

    We report the performance study of a 2% atomic doped ceramic Nd:YAG rod for long pulse laser operation in the millisecond regime with pulse duration in the range of 0.5-20 ms. A maximum average output power of 520 W with 180 J maximum pulse energy has been achieved with a slope efficiency of 5.4% using a dual rod configuration, which is the highest for typical lamp pumped ceramic Nd:YAG lasers. The laser output characteristics of the ceramic Nd:YAG rod were revealed to be nearly equivalent or superior to those of high-quality single crystal Nd:YAG rod. The laser pump chamber and resonator were designed and optimized to achieve a high efficiency and good beam quality with a beam parameter product of 16 mm mrad (M2˜47). The laser output beam was efficiently coupled through a 400 μm core diameter optical fiber with 90% overall transmission efficiency. This ceramic Nd:YAG laser will be useful for various material processing applications in industry.

  12. Design and study of photomultiplier pulse-shaping amplifier powered by the current flowing through a voltage divider

    International Nuclear Information System (INIS)

    Vladimir Popov

    2003-01-01

    A new version of Photomultiplier Tube (PMT) pulse amplifier, entirely powered by the current flowing through the base voltage divider, was designed and tested. This amplifier was designed for application in the JLAB G0 Experiment E00-006 as a part of high voltage base for XP2262 Photonis PMT. According to JLAB G0 experiment requirement, these PMT's operate with plastic scintillators at high counting rate (about MHz). Tests in JLAB experimental Hall C indicate that low energy gamma background cause up to 0.1 mA of PMT average anode current (without amplifier). At this radiation condition, PMT gain decreases by 50% within about 1 month of operation. The amplifier needs to reduce PMT anode current and to shape PMT anode pulse prior to sending it through a long cable line (more then 400 ft of RG-213 and RG-58 coax cables). Shaping of the PMT output pulse helps to reduce attenuation effect of the long cable line without significant reduction of timing accuracy. The results of this study of designed amplifier and PMT plus amplifier system are presented

  13. Experimental study on vapor explosion induced by pressure pulse in coarse mixing of hot molten metal and water

    International Nuclear Information System (INIS)

    Inoue, A.; Tobita, Y.; Aritomi, M.; Takahashi, M.; Matsuzaki, M.

    2004-01-01

    An experimental study was done to investigate characteristics of metal-water interaction, when a mount of hot liquid metal is injected into the water. The test section is a vertical shock tube of 60mm in inner diameter and 1200mm in length. A special injector which is designed to inject hot metal of controlled volume and flow rate is attached at the top of the tube. When the hot metal is injected in the water and comes down at a position of the test vessel, a trigger pressure pulse is generated at the bottom of the test tube. Local transient pressures along the tube are measured by piezo pressure transducers. The following items were investigated in the experiment; 1) The criteria to cause a vapor explosion, 2) Transient behaviors and propagation characteristics of pressure wave in the mixing region. 3) Effects of triggering pulse, injection temperature and mass of hot molten metal on the peak pressure. The probability of the vapor explosion jumped when the interface temperature at the molten metal-water direct contact is higher than the homogeneous nucleation temperature of water and the triggering pulse becomes larger than 0.9MPa. Two types of the pressure propagation modes are observed, one is the detonative mode with a sharp rise and other is usual pressure mode with a mild rise. (author)

  14. Structural and dynamical properties of solvated electrons; a study of kinetic spectroscopy using pulse radiolysis

    International Nuclear Information System (INIS)

    Huis, C. van

    1977-01-01

    In this thesis the pulse radiolysis experiments of hexamethyl-phosphortriamide (HMPA), propanol-1, 3-methylpentane and mixtures of propanol-1 and 3-methylpentane are reported. In the pulse radiolysis of HMPA, carried out at room temperature, the high yield of esub(s) - (G=2) and the very high wavelength of the maximum absorption (max= 2200 nm) in the esub(s) - absorption spectrum are explained by considering the aprotic nature and the molecular structure of this compound. In the experiment with propanol-1 (temperature range 93deg-123degK) a temporal shift to lower wavelengths in the time range of 10 s-10 ms is observed. In further experiments biphenyl was used as electron scavenger. It was concluded that after the electron pulse the following sequence of events takes place: 1) electron redistribution in times shorter than 1 s; 2) dipole reorientation during 10 s-10 ms; 3) recombination of a part of the solvated electrons; 4) a reaction of the solvated electrons with the neighbouring propanol-1 molecules. In the experiments with 3-methylpentane at 103deg-113degK an esub(s) - absorption band with third order decay kinetics was observed. This is attributed to geminate recombination. The activation energy of the recombination process was 0.4 eV. The experiments with mixtures of propanol-1 and 3-methylpentane were carried out at 103degK. At low propanol-1 concentrations the build-up at 500 nm obeys first order kinetics, whereas at high concentrations this build-up can be split up into three first order components, as was measured in pure propanol-1. The half-lives of the three components were in the ratio of 1:10:100. In the last chapter theoretical models for the electron redistribution and the matric relaxation are discussed and compared with the experiments

  15. Conceptual moderator studies for the Spallation Neutron Source short-pulse second target station

    Energy Technology Data Exchange (ETDEWEB)

    Gallmeier, F. X., E-mail: gallmeierfz@ornl.gov; Lu, W.; Riemer, B. W.; Zhao, J. K.; Herwig, K. W.; Robertson, J. L. [Instrument and Source Division, Oak Ridge National Laboratory, P.O. Box 2008, MS6466, Oak Ridge, Tennessee 37831 (United States)

    2016-06-15

    Candidate moderator configurations for a short-pulse second target station (STS) at the Oak Ridge National Laboratory Spallation Neutron Source (SNS) have been identified using a global optimizer framework built around the MCNPX particle transport code. Neutron brightness metrics were selected as the figure-of-merit. We assumed that STS would use one out of six proton pulses produced by an SNS accelerator upgraded to operate at 1.3 GeV proton energy, 2.8 MW power and 60 Hz repetition rate. The simulations indicate that the peak brightness can be increased by a factor of 5 and 2.5 on a per proton pulse basis compared to the SNS first target station for both coupled and decoupled para-hydrogen moderators, respectively. Additional increases by factors of 3 and 2 were demonstrated for coupled and decoupled moderators, respectively, by reducing the area of neutron emission from 100 × 100 mm{sup 2} to 20 × 20 mm{sup 2}. This increase in brightness has the potential to translate to an increase of beam intensity at the instruments’ sample positions even though the total neutron emission of the smaller moderator is less than that of the larger. This is especially true for instruments with small samples (beam dimensions). The increased fluxes in the STS moderators come at accelerated poison and de-coupler burnout and higher radiation-induced material damage rates per unit power, which overall translate into lower moderator lifetimes. A first effort was undertaken to group decoupled moderators into a cluster collectively positioning them at the peak neutron production zone in the target and having a three-port neutron emission scheme that complements that of a cylindrical coupled moderator.

  16. Decomposition of three volatile organic compounds by nanosecond pulsed corona discharge: Study of by-product formation and influence of high voltage pulse parameters

    Science.gov (United States)

    Jarrige, Julien; Vervisch, Pierre

    2006-06-01

    Increasing concerns over atmospheric pollution has motivated research into technologies able to remove volatile organic compounds (VOC's) from gas streams. The aim of this paper is to understand the chemical and physical mechanisms implied in the decomposition of VOC's in a filamentary nonthermal plasma discharge. Experiments have been carried out on three pollutants (propane, propene, and isopropyl alcohol) in dry air at atmospheric pressure using a wire to cylinder corona discharge generated by a homemade nanosecond rise time high voltage pulse generator. The resulting plasma efficiently destructs propane, propene, or isopropyl alcohol at a concentration of 500 ppm with low specific input energies (less than 500 J/L), but the poor oxidation rate leads to the formation of numerous by-products (acetone, formaldehyde, formic acid, and methyl nitrate) whose concentration can reach some hundreds of ppm. We also investigated the effect of pulse parameters on VOC removal efficiency. Neither pulse peak value nor rise time (in the range of 4-12 ns) appears to have a significant influence on the VOC decomposition rates. Therefore, we believe that the way the energy is deposited in the plasma does not modify the density of active species (radicals, ions) in the streamers. The production of energetic electrons is not enhanced by the external applied field, and the only effective parameter may be the local field in the streamer head, which is almost the same (around 500 Td) whatever the voltage (above the inception value).

  17. Decomposition of three volatile organic compounds by nanosecond pulsed corona discharge: Study of by-product formation and influence of high voltage pulse parameters

    International Nuclear Information System (INIS)

    Jarrige, Julien; Vervisch, Pierre

    2006-01-01

    Increasing concerns over atmospheric pollution has motivated research into technologies able to remove volatile organic compounds (VOC's) from gas streams. The aim of this paper is to understand the chemical and physical mechanisms implied in the decomposition of VOC's in a filamentary nonthermal plasma discharge. Experiments have been carried out on three pollutants (propane, propene, and isopropyl alcohol) in dry air at atmospheric pressure using a wire to cylinder corona discharge generated by a homemade nanosecond rise time high voltage pulse generator. The resulting plasma efficiently destructs propane, propene, or isopropyl alcohol at a concentration of 500 ppm with low specific input energies (less than 500 J/L), but the poor oxidation rate leads to the formation of numerous by-products (acetone, formaldehyde, formic acid, and methyl nitrate) whose concentration can reach some hundreds of ppm. We also investigated the effect of pulse parameters on VOC removal efficiency. Neither pulse peak value nor rise time (in the range of 4-12 ns) appears to have a significant influence on the VOC decomposition rates. Therefore, we believe that the way the energy is deposited in the plasma does not modify the density of active species (radicals, ions) in the streamers. The production of energetic electrons is not enhanced by the external applied field, and the only effective parameter may be the local field in the streamer head, which is almost the same (around 500 Td) whatever the voltage (above the inception value)

  18. Electron gain and electron loss radicals stabilized on the purine and pyrimidine of a cocrystal exhibiting base-base interstacking: ESR-ENDOR of X-irradiated adenosine:5-bromouracil

    International Nuclear Information System (INIS)

    Kar, L.; Bernhard, W.A.

    1983-01-01

    The predominant free radicals trapped in cocrystals of adenosine:5-bromouracil X-irradiated at 12 0 K were identified by ESR-ENDOR spectroscopy and the radical reactions were followed upon annealing to 480 0 K. The dominant electron abstraction and electron addition products stabilized on the bases at 12 0 K are observed to be the bromouracil π-cation and the adenine π-cation and π-anion. The formation of an anion on bromouracil is inferred from the presence of a radical formed by deuterium addition to C 6 of bromouracil at higher temperatures. Above 40 0 K the bromouracil π-cation appears to decay by recombination and is reduced to undetectable levels at approx.170 0 K. Both adenine π-ions are also observed to decay within the same temperature range. Above 200 0 K hydrogen adducts are stabilized on the bases. Experiments using partially deuterated cocrystals indicate that the H-adducts are formed via both hydrogen addition and protonation of the respective anions. Two hydrogen abstraction radicals stabilized on the sugar residue are detectable at temperatures above 200 0 K, but these may be present at much lower temperatures. The results presented here question the generally accepted hypothesis that, in the presence of purine:pyrimidine stacking interactions, holes are predominantly transferred to the purines while electrns are predominantly transferred to the pyrimidines

  19. Method of summation of amplitudes of coinciding pulses from Ge(Li) detectors used to study cascades of gamma-transitions in (n,#betta#) reaction

    International Nuclear Information System (INIS)

    Bogdzel', A.A.; Vasil'eva, Eh.V.; Elizarov, O.I.

    1982-01-01

    Main performanes and peculiarities of spectrometer based on the coincidence pulse amplitude total-count method and containing two Ge(La) detectors with transmission neutron spectrometer - IBR-30 pulse reactor are considered. It is shown on the 35 Cl(n, #betta#) reaction that the method of summalion of amplitudes of coinciding pulses from the Ge(Li) detector can be used to study the cascades of two #betta#-transitions with a total energy similar to the neutron binding energy. The shape of the response function of this spectrometer was studied versus the energies of #betta#-transition cascades

  20. Study of γ-irradiated lithographic polymers by electron spin resonance and electron nuclear double resonance

    International Nuclear Information System (INIS)

    Schlick, S.; Kevan, L.

    1982-01-01

    The room temperature gamma irradiation degradation of the lithographic polymers, poly(methylmethacrylate) (PMMA), poly(methyl-α-chloroacrylate) (PMCA), poly(methyl-α-fluoroacrylate) (PMFA), and poly(methylacrylonitrile) (PMCN), have been studied by electron spin resonance and electron nuclear double resonance (ENDOR) to assess their molecular degradation processes of relevance to electron beam lithography. Two classes of radicals are found, chain radicals and chain scission radicals. PMMA and PMCA mainly form chain scission radicals consistent with degradation while for PMCN the resolution is poorer, and this is only probable. PMFA forms mainly chain radicals consistent with predominant crosslinking. The total radical yield is greatest in PMCA and PMCN. ENDOR is used to assess the compactness of the radiation degradation region for PMMA and PMCA and hence the potential resolution of the resist; this appears to be about the same for these methacrylate polymers

  1. Multi-wavelength study of PPDs using an OPO tunable pulse laser microscope system

    International Nuclear Information System (INIS)

    Yoshimura, Koji; Nakamura, Isamu

    2012-01-01

    We have developed a new pulsed laser microscope system whose wavelength is continuously tunable from 410 nm to 2200 nm by using an optical parametric oscillator (OPO) laser system. The laser spot can be focused to ∼2μm diameter, small enough to measure pixel-by-pixel performance of PPDs (pixelated photon detectors). Using multi-wavelength laser light, we plan to probe PPDs at various depths, thanks to their different penetration lengths in the silicon layer. In this paper, details of the commissioning of the laser microscope system and pilot measurements on a PPD at several wavelengths will be presented.

  2. Multi-wavelength study of PPDs using an OPO tunable pulse laser microscope system

    Energy Technology Data Exchange (ETDEWEB)

    Yoshimura, Koji, E-mail: koji.yoshimura@kek.jp [High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Nakamura, Isamu [High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan)

    2012-12-11

    We have developed a new pulsed laser microscope system whose wavelength is continuously tunable from 410 nm to 2200 nm by using an optical parametric oscillator (OPO) laser system. The laser spot can be focused to {approx}2{mu}m diameter, small enough to measure pixel-by-pixel performance of PPDs (pixelated photon detectors). Using multi-wavelength laser light, we plan to probe PPDs at various depths, thanks to their different penetration lengths in the silicon layer. In this paper, details of the commissioning of the laser microscope system and pilot measurements on a PPD at several wavelengths will be presented.

  3. Neutron scattering studies of the dynamics of biopolymer-water systems using pulsed-source spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    Middendorf, H.D. [Univ. of Oxford (United Kingdom); Miller, A. [Stirling Univ., Stirling (United Kingdom)

    1994-12-31

    Energy-resolving neutron scattering techniques provide spatiotemporal data suitable for testing and refining analytical models or computer simulations of a variety of dynamical processes in biomolecular systems. This paper reviews experimental work on hydrated biopolymers at ISIS, the UK Pulsed Neutron Facility. Following an outline of basic concepts and a summary of the new instrumental capabilities, the progress made is illustrated by results from recent experiments in two areas: quasi- elastic scattering from highly hydrated polysaccharide gels (agarose and hyaluronate), and inelastic scattering from vibrational modes of slightly hydrated collagen fibers.

  4. Resolved multisite OH-attack on aqueous aniline studied by pulse radiolysis

    International Nuclear Information System (INIS)

    Solar, S.; Solar, W.; Getoff, N.

    1986-01-01

    The individual formation and decay kinetics as well as the absorption characteristics of the simultaneously formed primary species by OH attack on aniline in aqueous solution (pH 8-9.6), saturated with N 2 O, have been determined by pulse radiolysis combined with a computer optimization procedure. Further the rate constant of e - sub(aq) with aniline was determined to (3.0+-0.1) x l0 7 dm 3 mol -1 cm -1 . Qualitative analysis of final products were also performed. (author)

  5. Study of two-zone reactor system using a pulsed neutron technique

    Energy Technology Data Exchange (ETDEWEB)

    Shishin, B P; Platovskikh, Yu A; Didejkin, T S

    1977-05-01

    Theoretical and experimental investigations of a neutron flux time dependence after a sport fast neutron pulse in a reactor core - neutron reflector multiplying system have been conducted. A correlation between eigenvalues governing neutron flux decrease at t..-->..infinity for the two-zone system and eigenvalues for each zone has been established in terms of the one-group diffusion approximation. Experiments have been performed in an experimental subcritical assembly comprising a cylindrical uranium core surrounded by a radial water reflector with different boric acid concentrations.

  6. Study of a pulsed discharge in nitrogen: the N2 laser

    Energy Technology Data Exchange (ETDEWEB)

    Spyrou, N

    1979-01-01

    The characteristics of the pulsed nitrogen discharge and the power supply circuit of an N2 laser operating in the UV are investigated. Following a review of the characteristics of molecular lasers in general and the N2 laser in particular, a theoretical model based on a simultaneous description of the electric circuit and the discharge is developed to explain such laser characteristics as current evolution and electron density and temperature and to allow the calculation of laser energy levels. The theoretical model is found to be in agreement with experimental results, and optimal conditions for the operation of the experimental laser are obtained.

  7. Neutron scattering studies of the dynamics of biopolymer-water systems using pulsed-source spectrometers

    International Nuclear Information System (INIS)

    Middendorf, H.D.; Miller, A.

    1994-01-01

    Energy-resolving neutron scattering techniques provide spatiotemporal data suitable for testing and refining analytical models or computer simulations of a variety of dynamical processes in biomolecular systems. This paper reviews experimental work on hydrated biopolymers at ISIS, the UK Pulsed Neutron Facility. Following an outline of basic concepts and a summary of the new instrumental capabilities, the progress made is illustrated by results from recent experiments in two areas: quasi- elastic scattering from highly hydrated polysaccharide gels (agarose and hyaluronate), and inelastic scattering from vibrational modes of slightly hydrated collagen fibers

  8. Redox chemistry of orange I and orange II: a pulse radiolysis study

    International Nuclear Information System (INIS)

    Yadav, P.; Sharma, K.K.; Rao, B.S.M.; O'Neill, P.; Oakes, J.; Batchelor, S.N.

    2004-01-01

    The relative reactivities of different tautomeric forms of model azo dyes (Orange I and Orange II) with oxidising and reducing radicals are investigated using pulse radiolysis technique. The rate of the reaction of N 3 with Orange I is diffusion controlled and the order of the reactivity among the tautomers is common ion > hydrazone > azo, whereas a reverse trend was seen in the reaction of e aq . The reducing alcohol radicals react with Orange II with k values in the range (1-3) x 10 9 dm 3 mol -1 s -1 . The relevant reaction mechanism is discussed. (author)

  9. Pulse radiolysis studies of the interaction of tea polyphenol derivatives with oxidizing OH adduct of thymine

    International Nuclear Information System (INIS)

    Jiang Yue; Li Hucheng; Yao Side; Zuo Zhihua; Wang Zailan; Zhang Jiashan; Lin Nianyun

    1996-01-01

    The electron transfer reactions between oxidizing OH adduct of thymine with tea polyphenol derivatives has been investigated by pulse radiolysis. The tea polyphenol derivatives are identified as good antioxidants for reduction of oxidizing OH adducts of thymine. From buildup kinetic analysis of radical phenoxyl product, the rate constants for reactions of the N 3 radical with tea polyphenol derivatives have been determined to be (8-9) x 10 9 dm 3 /mol s, while the rate constants of electron transfer from tea polyphenol derivatives to oxidizing OH adducts of thymine was obtained to be around 10 9 dm 3 /mol s. Copyright direct C 1996 Elsevier Science Ltd

  10. A pulse radiolysis study of the reaction of the sulphate radical ion in aqueous solutions of styrene

    International Nuclear Information System (INIS)

    McAskill, N.A.; Sangster, D.F.

    1979-01-01

    The ultraviolet absorption spectra of the transient species formed during the pulse radiolysis of styrene and peroxydisulfate solutions showed that a benzyl-type radical was formed from styrene and the SO 4 - radical. The effect of adding Cl - was also studied. These results are in conflict with the claim that a phenylethyl radical was formed from SO 4 - via the styrene cation radical. That study was made on acetonitrile solutions of styrene, S 2 O 8 2- CUCl 2 and LiCl and the present results suggest that up to 70% of the SO 4 - radicals may have been converted into Cl 2 - radical which then reacted with styrene

  11. RF Pulsed Heating

    Energy Technology Data Exchange (ETDEWEB)

    Pritzkau, David P.

    2002-01-03

    RF pulsed heating is a process by which a metal is heated from magnetic fields on its surface due to high-power pulsed RF. When the thermal stresses induced are larger than the elastic limit, microcracks and surface roughening will occur due to cyclic fatigue. Pulsed heating limits the maximum magnetic field on the surface and through it the maximum achievable accelerating gradient in a normal conducting accelerator structure. An experiment using circularly cylindrical cavities operating in the TE{sub 011} mode at a resonant frequency of 11.424 GHz is designed to study pulsed heating on OFE copper, a material commonly used in normal conducting accelerator structures. The high-power pulsed RF is supplied by an X-band klystron capable of outputting 50 MW, 1.5 {micro}s pulses. The test pieces of the cavity are designed to be removable to allow testing of different materials with different surface preparations. A diagnostic tool is developed to measure the temperature rise in the cavity utilizing the dynamic Q change of the resonant mode due to heating. The diagnostic consists of simultaneously exciting a TE{sub 012} mode to steady-state in the cavity at 18 GHz and measuring the change in reflected power as the cavity is heated from high-power pulsed RF. Two experimental runs were completed. One run was executed at a calculated temperature rise of 120 K for 56 x 10{sup 6} pulses. The second run was executed at a calculated temperature rise of 82 K for 86 x 10{sup 6} pulses. Scanning electron microscope pictures show extensive damage occurring in the region of maximum temperature rise on the surface of the test pieces.

  12. Pulse holographic measurement techniques

    International Nuclear Information System (INIS)

    Kim, Cheol Jung; Baik, Seong Hoon; Hong, Seok Kyung; Kim, Jeong Moog; Kim, Duk Hyun

    1992-01-01

    With the development of laser, remote inspection techniques using laser have been growing on. The inspection and measurement techniques by pulse holography are well-established technique for precise measurement, and widely used in various fields of industry now. In nuclear industry, this technology is practically used because holographic inspection is remote, noncontact, and precise measurement technique. In relation to remote inspection technology in nuclear industry, state-of-the art of pulse HNDT (Holographic non-destructive testing) and holographic measurement techniques are examined. First of all, the fundamental principles as well as practical problems for applications are briefly described. The fields of pulse holography have been divided into the HNDT, flow visualization and distribution study, and other application techniques. Additionally holographic particle study, bubble chamber holography, and applications to other visualization techniques are described. Lastly, the current status for the researches and applications of pulse holography to nuclear industry which are carried out actively in Europe and USA, is described. (Author)

  13. Weekly azathioprine pulse versus daily azathioprine in the treatment of Parthenium dermatitis: A non-inferiority randomized controlled study

    Directory of Open Access Journals (Sweden)

    Kaushal K Verma

    2015-01-01

    Full Text Available Background: Azathioprine in daily doses has been shown to be effective and safe in the treatment of Parthenium dermatitis. Weekly pulses of azathioprine (WAP are also effective, but there are no reports comparing the effectiveness and safety of these two regimens in this condition. Aims: To study the efficacy and safety of WAP and daily azathioprine in Parthenium dermatitis. Methods: Sixty patients with Parthenium dermatitis were randomly assigned to treatment with azathioprine 300 mg weekly pulse or azathioprine 100 mg daily for 6 months. Patients were evaluated every month to assess the response to treatment and side effects. Results: The study included 32 patients in the weekly azathioprine group and 28 in the daily azathioprine group, of whom 25 and 22 patients respectively completed the study. Twenty-three (92% patients on WAP and 21 (96% on daily azathioprine had a good or excellent response. The mean pretreatment clinical severity score decreased from 26.4 ± 14.5 to 4.7 ± 5.1 in the WAP group, and from 36.1 ± 18.1 to 5.7 ± 6.0 in the daily azathioprine group, which was statistically significant and comparable (P = 0.366. Patients on WAP had a higher incidence of adverse effects (P = 0.02. Limitations: The study had a small sample size and the amount of clobetasol propionate used in each patient was not determined, though it may not have affected the study outcome due to its comparable use in both groups. Conclusions: Azathioprine 300 mg weekly pulse and 100 mg daily dose are equally effective and safe in the treatment of Parthenium dermatitis.

  14. Comparative Study on the Pulse Wave Variables and Sasang Constitution in Cerebral Infarction Patients and Healthy Subjects

    Directory of Open Access Journals (Sweden)

    Ko KiDuk

    2007-06-01

    Full Text Available This study was performed to determine whether a pulse analyzer was useful 1 to characterize the variables of pulse wave of cerebral infarction patieno (CI, compared with those of healthy subjects, as well as 2 to determine Sasang Constitution in CI and healthy subjects. 1. Calibrated in Gwan, the amount of energy(Energy, height of main peak(H1, height of aorticvalley(H2, height of aortic peak(H3, total area of pulse wave(At, and area of main peak width(Aw of the CI group were higher than those of the healthy group. 2. Calibrated in Cheek, Energy, H1, H2, H3, height of valve valley(H4, At, Aw, and main peak angle(MPA of the CI group were higher than those of the healthy group. 3. Among the healthy (subjects group, Taeumin showed the highest contact pressure(CP and height of valve peak(H5 calibrated in Chon. The main peak width divided by whole time of pulse wave(MPW/T calibrated in Gwan and Cheok, was highest in Soyangin and was lowest in Taeumin. The H3 divided by H1(H3/H1 and the time to valve valley minus the time to main peak and divided by T[(T4-T1/T] calibrated in Cheek were highest in Soyangin. The time to main peak(T1 was longest in Soumin. 4. Among the CI group, At calibrated in Chon was widest in Taeumin and was narrowest in Soumin The time to aortic peak(T3 calibrated in Cheek was longest in Soumin and was shortest in Soyangin. The time to valve peak(T5 was shortest in Soyangin. 5. There were main effects of cerebral infarction in the area of systolic period(As and area of diastolic period(Ad calibrated in Chon, Energy calibrated in Cwan, and Energy, H1, H2, H3, (H4+H5/Hl, and MPA calibrated in Cheek. 6. There were main effects of Sasang Constitution in (T4-T1/T, area of systolic period(As, and Ad calibrated in Chon. 7. The interactions between the cerebral infarction and Sasang Constitution were observed in H5/H1 , T, At, As, Ad, and MPA calibrated in Chon, H4, T4, (T4-T1/T, As, and Ad calibrated in Cwan, and 74,75, and MPW calibrated

  15. Experimental and modelling study of pulsed optically stimulated luminescence in quartz, marble and beta irradiated salt

    International Nuclear Information System (INIS)

    Pagonis, V; Mian, S M; Barnold, C; Chithambo, M L; Christensen, E

    2009-01-01

    Optical stimulation luminescence (OSL) signals can be obtained using continuous-wave optical stimulation (CW-OSL), the linear modulation optical stimulation method (LM-OSL) and the time-resolved optical stimulation (TR-OSL) method. During TR-OSL measurements, the stimulation and emission of luminescence are experimentally separated in time by using short light pulses. This paper presents new TR-OSL data for annealed high purity synthetic quartz, for marble and for commercially available iodized salt. A new type of behaviour for TR-OSL signals for quartz and iodized salt is presented, in which the OSL signal exhibits a nonmonotonic behaviour during optical stimulation; this type of behaviour has not been reported previously in the literature for quartz. Furthermore, a luminescence component with very long luminescence lifetime is reported for some quartz aliquots, which may be due to the presence of a delayed-OSL (DOSL) mechanism in quartz. A new kinetic model for TR-OSL in quartz is presented, which is based on a main electron trap and on several luminescence centres. The model is used to quantitatively fit several sets of experimental data of pulsed optically stimulated luminescence from quartz.

  16. Positron and positronium annihilation in low-dielectric-constant films studied by a pulsed positron beam

    International Nuclear Information System (INIS)

    Suzuki, R.; Ohdaira, T.; Kobayashi, Y.; Ito, K.; Yu, R.S.; Shioya, Y.; Ichikawa, H.; Hosomi, H.; Ishikiriyama, K.; Shirataki, H.; Matsuno, S.; Xu, J.

    2004-01-01

    Positron and positronium annihilation in porous low-dielectric-constant (low-k) films deposited by plasma-enhanced chemical vapor deposition (PECVD) and spin-on dielectric (SOD) have been investigated by means of positron annihilation lifetime spectroscopy (PALS) and age-momentum correlation (AMOC) spectroscopy with a pulsed slow positron beam. The ortho-positronium (o-Ps) lifetime strongly depends on the deposition condition. In general, PECVD low-k films have shorter o-Ps lifetimes than SOD low-k films, indicating PECVD low-k films have smaller pores. Since o-Ps diffusion and escaping from the surface occurs in most of porous SOD films, three-gamma annihilation measurement is important. To investigate o-Ps behavior in SOD films, we have carried out two-dimensional (2D) PALS measurement, which measures annihilation time and pulse-height of the scintillation detector simultaneously. Monte-Carlo simulation of the o-Ps diffusion and escaping in porous films has been carried out to simulate the 2D-PALS results. (orig.)

  17. Study of time-domain digital pulse shaping algorithms for nuclear signals

    International Nuclear Information System (INIS)

    Zhou Jianbin; Tuo Xianguo; Zhu Xing; Liu Yi; Zhou Wei; Lei Jiarong

    2012-01-01

    With the development on high-speed integrated circuit, fast high resolution sampling ADC and digital signal processors are replacing analog shaping amplifier circuit. This paper firstly presents the numerical analysis and simulation on R-C shaping circuit model and C-R shaping circuit model. Mathematic models are established based on 1 st order digital differential method and Kirchhoff Current Law in time domain, and a simulation and error evaluation experiment on an ideal digital signal are carried out with Excel VBA. A digital shaping test for a semiconductor X-ray detector in real time is also presented. Then a numerical analysis for Sallen-Key(S-K) low-pass filter circuit model is implemented based on the analysis of digital R-C and digital C-R shaping methods. By applying the 2 nd order non-homogeneous differential equation,the authors implement a digital Gaussian filter model for a standard exponential-decaying signal and a nuclear pulse signal. Finally, computer simulations and experimental tests are carried out and the results show the possibility of the digital pulse processing algorithms. (authors)

  18. Study on ultrastructural changes in thyroid gland of rats exposed to pulsed electromagnetic wave

    International Nuclear Information System (INIS)

    Zhou Xiaoguang; Zeng Guiying; Ren Dongqing; Fang Henghu; Su Xiaoming; Huang Xiaofeng

    2006-01-01

    The work is to observe effects of PEMW (pulse electromagnetic wave) exposure on function and morphology of thyroid gland of rats. At different time points (24, 48, 96 and 192 h) after exposure to PEMW (E=115 kV m -1 , 12000 pulses), radioimmunoassay was performed to observe the levels of thyroid-stimulating hormone (TSH), thyroxine (T 4 ) and triiodo- thyronine (T 3 ) in sera of the male Sparague-Dawley rats. Optic microscopy and transmission electron microscopy (TEM) were used to observe structural changes of the thyroid gland at the time points. The T 3 , T 4 and TSH in sera increased significantly, reaching a peak at 24 h and decreasing gradually then. Although no obvious changes in the thyroid gland were observed under the optic microscope, some ultrastructural changes in the thyroid gland were found under the TEM. The ultrastructures were obviously changed at 12 h and aggravated until 48 h. In the experimented rats, dilatated endoplasmic reticulum gathered with lots of protein excretion, lipid droplet and heterochromatin gathered under the nucleus membranes were observed in follicular epithelial cells. These changes were palliated at 96 h but not recovered. PEMW can affect levels of hormones in sera and the hazard ultrastructural changes of thyroid gland. Endoplasmic reticulum is the main injured organelle. (authors)

  19. A study of flow performance and flooding in pulsed sieve plate extraction columns

    International Nuclear Information System (INIS)

    Zhang Quanrong; Wang Ruipian

    1986-01-01

    The pulsed sieve plate extraction columns could be divided into two types. The type II which has larger coalescence-damping coefficient K has an apparent transition region that widens when the K value has been increased. In this time, the operation condition in the column of type II is very different from that of type I. The flooding could be divided into three types: the flooding due to insufficient pulsing; emulsion flooding; and flooding due to dispersed phase and continuous phase that replace each other. The three kinds of flooding in the column of type II are very different from that in the column of type I. In the column of type II, when the value of K is about 2 to 3, emulsion flooding has occured and flooding capacity is the largest. In that column. The largest flooding capacity is usually larger than 1300 l/dm 2 · hr when the system 30% TBP(OK)-HNO 3 is used, but it cannot be used under normal conditions when the K value is larger

  20. In vitro study of the variable square pulse Er:YAG laser cutting efficacy for apicectomy.

    Science.gov (United States)

    Grgurević, Josko; Grgurević, Lovro; Miletić, Ivana; Karlović, Zoran; Krmek, Silvana Jukić; Anić, Ivica

    2005-06-01

    Variable square pulse (VSP) Er:YAG laser should be quicker than older Er:YAG lasers. The objectives were: (1) comparison of VSP laser and mechanical handpiece efficacy for apicectomy and (2) determination of optimal pulse width/energy/frequency combination. Sixty extracted, single-rooted mature human teeth with round apical parts were instrumented, root filled, cleaned, and divided into four groups. Apical 2 mm of each root were apicectomized with mechanical handpiece and Er:YAG laser with three different settings (LaserA = 200 mJ/300 microseconds/ 8 Hz; LaserB = 200 mJ/100 microseconds/8 Hz; LaserC = 380 mJ/100 microseconds/20 Hz). Timing results were statistically compared. LaserC was the most efficient setting. Differences between groups were significant except between LaserC-Mechanical and LaserA-LaserC (P < 0.05). VSP Er:YAG laser used for apicectomy is slower by a factor of 7-31 than mechanical handpiece, but treatment outcome is acceptable. Optimal settings for apicectomy with VSP laser are 380 mJ/100 microseconds/20 Hz. Copyright 2005 Wiley-Liss, Inc.

  1. NATO Advanced Study Institute on Chemical Crystallography with Pulsed Neutrons and Synchrotron X-Rays

    CERN Document Server

    Jeffrey, George

    1988-01-01

    X-ray and neutron crystallography have played an increasingly impor­ tant role in the chemical and biochemical sciences over the past fifty years. The principal obstacles in this methodology, the phase problem and com­ puting, have been overcome. The former by the methods developed in the 1960's and just recognised by the 1985 Chemistry Nobel Prize award to Karle and Hauptman, the latter by the dramatic advances that have taken place in computer technology in the past twenty years. Within the last decade, two new radiation sources have been added to the crystallographer's tools. One is synchrotron X-rays and the other is spallation neutrons. Both have much more powerful fluxes than the pre­ vious sources and they are pulsed rather than continuos. New techniques are necessary to fully exploit the intense continuos radiation spectrum and its pulsed property. Both radiations are only available from particular National Laboratories on a guest-user basis for scientists outside these Na­ tional Laboratories. Hi...

  2. Study on Nanostructures Induced by High-Current Pulsed Electron Beam

    Directory of Open Access Journals (Sweden)

    Bo Gao

    2012-01-01

    Full Text Available Four techniques using high-current pulsed electron beam (HCPEB were proposed to obtain surface nanostructure of metal and alloys. The first method involves the distribution of several fine Mg nanoparticles on the top surface of treated samples by evaporation of pure Mg with low boiling point. The second technique uses superfast heating, melting, and cooling induced by HCPEB irradiation to refine the primary phase or the second phase in alloys to nanosized uniform distributed phases in the matrix, such as the quasicrystal phase Mg30Zn60Y10 in the quasicrystal alloy Mg67Zn30Y3. The third technique involves the refinement of eutectic silicon phase in hypereutectic Al-15Si alloys to fine particles with the size of several nanometers through solid solution and precipitation refinement. Finally, in the deformation zone induced by HCPEB irradiation, the grain size can be refined to several hundred nanometers, such as the grain size of the hypereutectic Al-15Si alloys in the deformation zone, which can reach ~400 nm after HCPEB treatment for 25 pulses. Therefore, HCPEB technology is an efficient way to obtain surface nanostructure.

  3. A study of the transient plasma potential in a pulsed bi-polar dc magnetron discharge

    International Nuclear Information System (INIS)

    Bradley, J W; Karkari, S K; Vetushka, A

    2004-01-01

    The temporal evolution of the plasma potential, V p , in a pulsed dc magnetron plasma has been determined using the emissive probe technique. The discharge was operated in the 'asymmetric bi-polar' mode, in which the discharge voltage changes polarity during part of the pulse cycle. The probe measurements, with a time-resolution of 20 ns or better, were made along a line above the racetrack, normal to the plane of the cathode target, for a fixed frequency (100 kHz), duty cycle (50%), argon pressure (0.74 Pa) and discharge power (583 W). At all the measured positions, V p was found to respond to the large and rapid changes in the cathode voltage, V d , during the different phases of the pulse cycle, with V p always more positive than V d . At a typical substrate position (>80 mm from the target), V p remains a few volts above the most positive surface in the discharge at all times. In the 'on' phase of the pulse, the measurements show a significant axial electric field is generated in the plasma, with the plasma potential dropping by a total of about 30 V over a distance of 70 mm, from the bulk plasma to a position close to the beginning of the cathode fall. This is consistent with measurements made in the dc magnetron. During the stable 'reverse' phase of the discharge, for distances greater than 18 mm from the target, the axial electric field is found to collapse, with V p elevated uniformly to about 3 V above V d . Between the target and this field-free region an ion sheath forms, and the current flowing to the target is still an ion current in this 'reverse' period. During the initial 200 ns of the voltage 'overshoot' phase (between 'on' and 'reverse' phases), V d reached a potential of +290 V; however, close to the target, V p was found to attain a much higher value, namely +378 V. Along the line of measurement, the axial electric field reverses in direction in this phase, and an electron current of up to 9 A flows to the target. The spatial and temporal

  4. Pulse plating

    CERN Document Server

    Hansal, Wolfgang E G; Green, Todd; Leisner, Peter; Reichenbach, Andreas

    2012-01-01

    The electrodeposition of metals using pulsed current has achieved practical importance in recent years. Although it has long been known that changes in potential, with or without polarity reversal, can significantly affect the deposition process, the practical application of this has been slow to be adopted. This can largely be explained in terms of the complex relationship between the current regime and its effect on the electrodeposition process. In order to harness these effects, an understanding of the anodic and cathodic electrochemical processes is necessary, together with the effects of polarity reversal and the rate of such reversals. In this new monograph, the basics of metal electrodeposition from solution are laid out in great detail in seven distinct chapters. With this knowledge, the reader is able to predict how a given pulse train profile can be adopted to achieve a desired outcome. Equally important is the choice of a suitable rectifier and the ancillary control circuits to enable pulse platin...

  5. SU-F-J-225: Histology Study of MR Guided Pulsed Focused Ultrasound On Treatment of Prostate Cancer in Vivo

    Energy Technology Data Exchange (ETDEWEB)

    Chen, L; Cvetkovic, D; Chen, X; Wang, B; Gupta, R; Ma, C [Fox Chase Cancer Center, Philadelphia, PA (United States)

    2016-06-15

    Purpose: Our previous study demonstrated significant tumor growth delay in the mice treated with pulsed high intensity focused ultrasound (pHIFU). The purpose of this study is to understand the cell killing mechanisms of pHIFU. Methods: Prostate cancer cells (LNCaP), were grown orthotopically in 17 nude mice. Tumor-bearing mice were treated using pHIFU with an acoustic power of 25W, pulse width 100msec and 300 pulses in one sonication under MR guidance. Mutiple sonications were used to cover the whole tumor volume. The temperature (less than 40 degree centigrade in the focal spot) was monitored using MR thermometry. Animals were euthanized at pre-determined time points (n=2) after treatment: 0 hours; 6 hrs; 24 hrs; 48 hrs; 4 days and 7 days. Two tumorbearing mice were used as control. Three tumor-bearing mice were treated with radiation (RT, 2 Gy) using 6 MV photon beams. RT treated mice were euthanized at 0 hr, 6 hrs and 24 hrs. The tumors were processed for immunohistochemical (IHC) staining for PARP (a surrogate of apoptosis). A multispectral imaging analysis system was used to quantify the expression of PARP staining. Cell apoptosis was calculated based on the PARP expression level using the DAB analysis software. Results: Our data showed that PARP related apoptosis peaked at 48 hrs and 7 days in pHIFU treated mice, which is comparable to that for the RT group at 24 hrs. The preliminary results from this study were consistent with our previous study on tumor growth delay using pHIFU. Conclusion: Our results demonstrated that non-thermal pHIFU increased apoptotic tumor cell death through the PARP related pathway. MR guided pHIFU may have a great potential as a safe, noninvasive treatment modality for cancer therapy. This treatment modality may synergize with PARP inhibitors to achieve better therapeutic result.

  6. SU-F-J-225: Histology Study of MR Guided Pulsed Focused Ultrasound On Treatment of Prostate Cancer in Vivo

    International Nuclear Information System (INIS)

    Chen, L; Cvetkovic, D; Chen, X; Wang, B; Gupta, R; Ma, C

    2016-01-01

    Purpose: Our previous study demonstrated significant tumor growth delay in the mice treated with pulsed high intensity focused ultrasound (pHIFU). The purpose of this study is to understand the cell killing mechanisms of pHIFU. Methods: Prostate cancer cells (LNCaP), were grown orthotopically in 17 nude mice. Tumor-bearing mice were treated using pHIFU with an acoustic power of 25W, pulse width 100msec and 300 pulses in one sonication under MR guidance. Mutiple sonications were used to cover the whole tumor volume. The temperature (less than 40 degree centigrade in the focal spot) was monitored using MR thermometry. Animals were euthanized at pre-determined time points (n=2) after treatment: 0 hours; 6 hrs; 24 hrs; 48 hrs; 4 days and 7 days. Two tumorbearing mice were used as control. Three tumor-bearing mice were treated with radiation (RT, 2 Gy) using 6 MV photon beams. RT treated mice were euthanized at 0 hr, 6 hrs and 24 hrs. The tumors were processed for immunohistochemical (IHC) staining for PARP (a surrogate of apoptosis). A multispectral imaging analysis system was used to quantify the expression of PARP staining. Cell apoptosis was calculated based on the PARP expression level using the DAB analysis software. Results: Our data showed that PARP related apoptosis peaked at 48 hrs and 7 days in pHIFU treated mice, which is comparable to that for the RT group at 24 hrs. The preliminary results from this study were consistent with our previous study on tumor growth delay using pHIFU. Conclusion: Our results demonstrated that non-thermal pHIFU increased apoptotic tumor cell death through the PARP related pathway. MR guided pHIFU may have a great potential as a safe, noninvasive treatment modality for cancer therapy. This treatment modality may synergize with PARP inhibitors to achieve better therapeutic result.

  7. Intense pulsed light treatment for dry eye disease due to meibomian gland dysfunction; a 3-year retrospective study.

    Science.gov (United States)

    Toyos, Rolando; McGill, William; Briscoe, Dustin

    2015-01-01

    The purpose of this study was to determine the clinical benefits of intense-pulsed-light therapy for the treatment of dry-eye disease caused by meibomian gland dysfunction (MGD). MGD is the leading cause of evaporative dry eye disease. It is currently treated with a range of methods that have been shown to be only somewhat effective, leading to the need for advanced treatment options. A retrospective noncomparative interventional case series was conducted with 91 patients presenting with severe dry eye syndrome. Treatment included intense-pulsed-light therapy and gland expression at a single outpatient clinic over a 30-month study. Pre/post tear breakup time data were available for a subset of 78 patients. For all patients, a specially developed technique for the treatment of dry eye syndrome was applied as a series of monthly treatments until there was adequate improvement in dry eye syndrome symptoms by physician judgment, or until patient discontinuation. Primary outcomes included change in tear breakup time, self-reported patient satisfaction, and adverse events. Physician-judged improvement in dry eye tear breakup time was found for 68 of 78 patients (87%) with seven treatment visits and four maintenance visits on average (medians), and 93% of patients reported post-treatment satisfaction with degree of dry eye syndrome symptoms. Adverse events, most typically redness or swelling, were found for 13% of patients. No serious adverse events were found. Although preliminary, study results of intense-pulsed-light therapy treatment for dry eye syndrome caused by meibomian gland dysfunction are promising. A multisite clinical trial with a larger sample, treatment comparison groups, and randomized controlled trials is currently underway.

  8. Rapid thermal pulse annealing

    International Nuclear Information System (INIS)

    Miller, M.G.; Koehn, B.W.; Chaplin, R.L.

    1976-01-01

    Characteristics of recovery processes have been investigated for cases of heating a sample to successively higher temperatures by means of isochronal annealing or by using a rapid pulse annealing. A recovery spectra shows the same features independent of which annealing procedure is used. In order to determine which technique provides the best resolution, a study was made of how two independent first-order processes are separated for different heating rates and time increments of the annealing pulses. It is shown that the pulse anneal method offers definite advantages over isochronal annealing when annealing for short time increments. Experimental data by means of the pulse anneal techniques are given for the various substages of stage I of aluminium. (author)

  9. A 12 kV, 1 kHz, Pulse Generator for Breakdown Studies of Samples for CLIC RF Accelerating Structures

    CERN Document Server

    Soares, R H; Kovermann, J; Calatroni, S; Wuensch, W

    2012-01-01

    Compact Linear Collider (CLIC) RF structures must be capable of sustaining high surface electric fields, in excess of 200 MV/m, with a breakdown (BD) rate below 3×10-7 breakdowns/pulse/m. Achieving such a low rate requires a detailed understanding of all the steps involved in the mechanism of breakdown. One of the fundamental studies is to investigate the statistical characteristics of the BD rate phenomenon at very low values to understand the origin of an observed dependency of the surface electric field raised to the power of 30. To acquire sufficient BD data, in a reasonable period of time, a high repetition rate pulse generator is required for an existing d.c. spark system at CERN. Following BD of the material sample the pulse generator must deliver a current pulse of several 10’s of Amperes for ~2 μs. A high repetition rate pulse generator has been designed, built and tested; this utilizes pulse forming line technology and employs MOSFET switches. This paper describes the design of the pulse generat...

  10. Tokamak burn cycle study: a data base for comparing long pulse and steady-state power reactors

    International Nuclear Information System (INIS)

    Ehst, D.A.; Brooks, J.N.; Cha, Y.; Evans, K. Jr.; Hassanein, A.; Kim, S.; Majumdar, S.; Misra, B.; Stevens, H.C.

    1983-11-01

    Several distinct operating modes (conventional ohmic, noninductive steady state, internal transformer, etc.) have been proposed for tokamaks. Our study focuses on capital costs and lifetime limitations of reactor subsystems in an attempt to quantify sensitivity to pulsed operation. Major problem areas considered include: thermal fatigue on first wall, limiter/divertor; thermal energy storage; fatigue and eddy current heating in toroidal field coils; electric power supply costs; and noninductive driver costs. We assume a high availability and low cost of energy will be mandatory for a commercial fusion reactor, and we characterize improvements in physics (current drive efficiency) and engineering (superior materials) which will help achieve these goals for different burn cycles

  11. Quantitative study of the ionization-induced refraction of picosecond laser pulses in gas-jet targets

    International Nuclear Information System (INIS)

    Mackinnon, A.J.; Borghesi, M.; Iwase, A.; Jones, M.W.; Pert, G.J.; Rae, S.; Burnett, K.; Willi, O.

    1996-01-01

    A quantitative study of refractive whole beam defocusing and small scale breakup induced by optical ionization of subpicosecond and picosecond, 0.25 and 1 μm, laser pulses in gas-jet targets at densities above 1x10 19 cm -3 has been carried out. A significant reduction of the incident laser intensity was observed due to refraction from ionization-induced density gradients. The level of refraction measured with optical probing correlated well with the fraction of energy transmitted through the plasma. The numerical and analytical models were found to agree well with experimental observations. copyright 1996 The American Physical Society

  12. Reactivity of OH radicals with chlorobenzoic acids-A pulse radiolysis and steady-state radiolysis study

    DEFF Research Database (Denmark)

    Zona, Robert; Solar, Sonja; Getoff, Nikola

    2010-01-01

    The reactions of OH radicals with 2-, 3-, 4-chlorobenzoic acids (ClBzA) and chlorobenzene (ClBz), k(OH+substrates)=(4.5−6.2)×109 dm3 mol−1 s−1, have been studied by pulse radiolysis in N2O saturated solutions. The absorption maxima of the OH-adducts were in the range of 320−340 nm. Their decay wa...... to degradation. The order for the efficiency of dehalogenation was 4->2->3-ClBzA. Several primary radiolytic products could be detected by HPLC. To evaluate the toxicity of final products a bacterial bioluminescence test was carried out....

  13. Pulse gas chromatographic study of adsorption of substituted aromatics and heterocyclic molecules on MIL-47 at zero coverage.

    Science.gov (United States)

    Duerinck, Tim; Couck, Sarah; Vermoortele, Frederik; De Vos, Dirk E; Baron, Gino V; Denayer, Joeri F M

    2012-10-02

    The low coverage adsorptive properties of the MIL-47 metal organic framework toward aromatic and heterocyclic molecules are reported in this paper. The effect of molecular functionality and size on Henry adsorption constants and adsorption enthalpies of alkyl and heteroatom functionalized benzene derivates and heterocyclic molecules was studied using pulse gas chromatography. By means of statistical analysis, experimental data was analyzed and modeled using principal component analysis and partial least-squares regression. Structure-property relationships were established, revealing and confirming several trends. Among the molecular properties governing the adsorption process, vapor pressure, mean polarizability, and dipole moment play a determining role.

  14. Producing High Intense Attosecond Pulse Train by Interaction of Three-Color Pulse and Overdense Plasma

    Science.gov (United States)

    Salehi, M.; Mirzanejad, S.

    2017-05-01

    Amplifying the attosecond pulse by the chirp pulse amplification method is impossible. Furthermore, the intensity of attosecond pulse is low in the interaction of laser pulse and underdense plasma. This motivates us to propose using a multi-color pulse to produce the high intense attosecond pulse. In the present study, the relativistic interaction of a three-color linearly-polarized laser-pulse with highly overdense plasma is studied. We show that the combination of {{ω }}1, {{ω }}2 and {{ω }}3 frequencies decreases the instance full width at half maximum reflected attosecond pulse train from the overdense plasma surface. Moreover, we show that the three-color pulse increases the intensity of generated harmonics, which is explained by the relativistic oscillating mirror model. The obtained results demonstrate that if the three-color laser pulse interacts with overdense plasma, it will enhance two orders of magnitude of intensity of ultra short attosecond pulses in comparison with monochromatic pulse.

  15. Experimental study of transmission of a pulsed focused beam through a skull phantom in nonlinear regime

    Energy Technology Data Exchange (ETDEWEB)

    Tsysar, S. A., E-mail: sergey@acs366.phys.msu.ru; Nikolaeva, A. V.; Khokhlova, V. A.; Yuldashev, P. V. [Physics Faculty, Moscow State University, Leninskie Gory, Moscow 119991 (Russian Federation); Svet, V. D. [Andreyev Acoustics Institute, 4, Shvernik Street, Moscow 117036 (Russian Federation); Sapozhnikov, O. A. [Physics Faculty, Moscow State University, Leninskie Gory, Moscow 119991 (Russian Federation); Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, 1013 NE 40th Street, Seattle, WA 98105 (United States)

    2015-10-28

    In the paper the use of receiving and radiating system, which allows to determine the parameters of bone by nonlinear pulse-echo technique and to image of brain structures through the skull bones, was proposed. Accuracy of the skull bone characterization is due to higher measured harmonic and is significantly better than in linear case. In the experimental part focused piezoelectric transducer with diameter 100 mm, focal distance 100 mm, the frequency of 1.092 MHz was used. It was shown that skull bone profiling can be performed with the use of 3rd harmonic since 1st harmonic can be used for visualization of the underlying objects. The use of wideband systems for both skull profiling and brain visualization is restricted by skull attenuation and resulting low effective sensitivity.

  16. Further study on heredity of liquid aluminum modified by electric pulse

    Directory of Open Access Journals (Sweden)

    Qi Jingang

    2011-08-01

    Full Text Available The remarkable heredity of liquid aluminum modified by electric pulse (EP, EPM has been uncovered. For better understanding from all aspects on the hereditary properties, the present research deals with the heredity destruction and the secondary EPM procedure. It is shown that the secondary EPM is capable of preventing the heredity reduction of EP-modified liquid aluminum, and that the final refining effect has a close relationship with technique parameters of the secondary EPM. Furthermore, at a certain superheated temperature depending on the initial EPM technique parameters, the heredity relationship of EP-modified liquid aluminum can be cut off during remelting. High temperature X-ray diffraction combining with the DSC tests also indicates that the EP-induced structure changes have almost disappeared at an elevated remelting temperature.

  17. Histochemical and polarization microscopic study of two cases of vegetable/pulse granuloma

    Directory of Open Access Journals (Sweden)

    Manjunatha B

    2008-01-01

    Full Text Available Vegetable granuloma (VG or pulse granuloma (PG results from the implantation of food particles of plant or vegetable origin. It is usually seen in the periapical or in the sulcus areas. These lesions have been described as a distinct entity and classified into central and peripheral lesions according to the location. Central lesions are asymptomatic, whereas peripheral lesions present as painless sub-mucosal swellings. Many authors have postulated that food particles in VG or PG get implanted and are rapidly digested, and sometimes partly get altered by host responses. The cellulose part of plant foods being indigestible persists in the form of hyaline material, whereas the starch matter gets digested. This cellulose moiety invokes chronic granulomatous response.

  18. Experimental study of transmission of a pulsed focused beam through a skull phantom in nonlinear regime

    International Nuclear Information System (INIS)

    Tsysar, S. A.; Nikolaeva, A. V.; Khokhlova, V. A.; Yuldashev, P. V.; Svet, V. D.; Sapozhnikov, O. A.

    2015-01-01

    In the paper the use of receiving and radiating system, which allows to determine the parameters of bone by nonlinear pulse-echo technique and to image of brain structures through the skull bones, was proposed. Accuracy of the skull bone characterization is due to higher measured harmonic and is significantly better than in linear case. In the experimental part focused piezoelectric transducer with diameter 100 mm, focal distance 100 mm, the frequency of 1.092 MHz was used. It was shown that skull bone profiling can be performed with the use of 3rd harmonic since 1st harmonic can be used for visualization of the underlying objects. The use of wideband systems for both skull profiling and brain visualization is restricted by skull attenuation and resulting low effective sensitivity

  19. Studies of closure phenomena in pinholes irradiated by Nd laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Auerbach, J.M.; Holmes, N.C.; Hunt, J.T.; Linford, G.J.

    1978-08-21

    The plasma closure of spatial filter pinholes is a critical parameter in the performance of high energy glass laser systems. Using 50 to 100 J, 300 psec FWHM laser pulses on the Janus laser, an investigation has been made on closure effects in 300 ..mu..m to 500 ..mu..m diameter pinholes of various materials and thicknesses. Calorimetry measurements have yielded data on pinhole transmission and intensity loading on the periphery of the pinhole. Ultrafast streak photography measurements indicate effective closure velocities of 2 x 10/sup 7/ cm/sec to 5 x 10/sup 7/ cm/sec. Scattered light measurements have shown the transmission loss through a typical spatial filter configuration to be primarily refractive in nature.

  20. Studies of closure phenomena in pinholes irradiated by Nd laser pulses

    International Nuclear Information System (INIS)

    Auerbach, J.M.; Holmes, N.C.; Hunt, J.T.; Linford, G.J.

    1978-01-01

    The plasma closure of spatial filter pinholes is a critical parameter in the performance of high energy glass laser systems. Using 50 to 100 J, 300 psec FWHM laser pulses on the Janus laser, an investigation has been made on closure effects in 300 μm to 500 μm diameter pinholes of various materials and thicknesses. Calorimetry measurements have yielded data on pinhole transmission and intensity loading on the periphery of the pinhole. Ultrafast streak photography measurements indicate effective closure velocities of 2 x 10 7 cm/sec to 5 x 10 7 cm/sec. Scattered light measurements have shown the transmission loss through a typical spatial filter configuration to be primarily refractive in nature