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Sample records for 217at 213po 209pb

  1. The continuum shell-model neutron states of 209Pb

    Ramendra Nath Majumdar

    2003-12-01

    The neutron strength distributions of the three high-spin 117/2, 2ℎ11/2 and 113/2 states of 209Pb have been obtained within the formalism of the core-polarisation effect where the effect of interaction of the neutron shell-model states of 209Pb with the collective vibrational states (originating also from the giant resonances) have been taken into consideration. The theoretical results have been discussed in the light of works on 117/2, 2ℎ11/2 and 113/2 neutron orbitals of 209Pb. The shell-model energies of the neutron states have been obtained by Skyrme–Hartree–Fock method.

  2. Contribution to construction and setup of a detection system for the focal plan of the BBS spectrometer. Application to study of the neutron emission decay of the resonant states populated by the reaction (4He,3He) at 42 MeV/u in nuclei 208Pb and 209Pb

    In order to realize an experimental program dedicated to nuclear structure studies we have conceived and constructed at IPN Orsay a detection system for the focal plane of the magnetic spectrometer BBS, installed at the cryogenic cyclotron AGOR of the laboratory KVI (The Netherlands). Two detection units, consisting each of two localization plans of the Cathode Strip Chamber (CSC) type, measure the position and angle of particle trajectory. This information is used for the determination of the reaction parameters at the target by a backtracking procedure. The identification of the reaction products is done by the measurement of their time-of-flight and energy loss. For light ions this task is assumed by plastic scintillators, and for heavy ions by a parallel plan detector (PPAC) and an ionization chamber. This detection system is well adapted to the requirements given by the detection of a large range of ions (protons to 36Ar at energies of several tenths of MeV/nucleon) as well as the big acceptance, the small dispersion and the aberration of the BBS. The results of the test show the good performances of the detection system. In a first experiment the focal plane detection system was coupled to the neutron multidetector EVEN in order to study the decay of resonant high spin states at high excitation energies by the (4He, 3He) reaction on 207Pb and 208Pb targets. The transfer spectra, inclusive and in coincidence, of the nuclei 208Pb and 209Pb show a striking resemblance except for an excitation energy shift which is due to the hole in the last neutron shell of 207Pb. The resonances at l 8 and l = 9 are clearly populated, in agreement with the predictions of the Bonaccorso-Brink model. A sizeable fraction of the decay of the l = 8 resonance is direct, but at excitation energies higher than 15 MeV (in 208Pb) the decay is mostly statistical. (author)

  3. Contribution to construction and setup of a detection system for the focal plan of the BBS spectrometer. Application to study of the neutron emission decay of the resonant states populated by the reaction ({sup 4}He,{sup 3}He) at 42 MeV/u in nuclei {sup 208}Pb and {sup 209}Pb; Contribution a la construction et a la mise au point d'un systeme de detection pour le plan focal du spectrometre BBS. Application a l'etude de la decroissance par emission de neutrons d'etats resonants peuples par la reaction ({sup 4}He,{sup 3}He) a 42 MeV/u dans les noyaux {sup 208}Pb et {sup 209}Pb

    Plankl-Chabib, Elke [Inst. de Physique Nucleaire, Paris-11 Univ., 91 - Orsay (France)

    1999-06-11

    In order to realizean experimental program dedicated to nuclear structure studies we have conceived and constructed at IPN Orsay a detection system for the focal plane of the magnetic spectrometer BBS, installed at the cryogenic cyclotron AGOR of the laboratory KVI (The Netherlands). Two detection units, consisting each of two localization plans of the Cathode Strip Chamber (CSC) type, measure the position and angle of particle trajectory. This information is used for the determination of the reaction parameters at the target by a backtracking procedure. The identification of the reaction products is done by the measurement of their time-of-flight and energy loss. For light ions this task is assumed by plastic scintillators, and for heavy ions by a parallel plan detector (PPAC) and an ionization chamber. This detection system is well adapted to the requirements given by the detection of a large range of ions (protons to {sup 36}Ar at energies of several tenths of MeV/nucleon) as well as the big acceptance, the small dispersion and the aberration of the BBS. The results of the test show the good performances of the detection system. In a first experiment the focal plane detection system was coupled to the neutron multidetector EVEN in order to study the decay of resonant high spin states at high excitation energies by the ({sup 4}He, {sup 3}He) reaction on {sup 207}Pb and {sup 208}Pb targets. The transfer spectra, inclusive and in coincidence, of the nuclei {sup 208}Pb and {sup 209}Pb show a striking resemblance except for an excitation energy shift which is due to the hole in the last neutron shell of {sup 207}Pb. The resonances at l 8 and l = 9 are clearly populated, in agreement with the predictions of the Bonaccorso-Brink model. A sizeable fraction of the decay of the l = 8 resonance is direct, but at excitation energies higher than 15 MeV (in {sup 208}Pb) the decay is mostly statistical.

  4. Activity determination of 229Th by means of liquid scintillation counting

    Liquid scintillation measurements of 229Th in radioactive equilibrium with its progenies were carried out. The counting efficiency was determined by means of a free parameter model. The measurements were made in a custom-built triple-to-double coincidence ratio (TDCR) system. In addition, a new portable mini-TDCR system with three channel photomultipliers and two commercial counters were tested. The decay of the short-lived 213Po requires great care, since it often occurs during the dead time of the counter systems. Also the rather short-lived 217At may decay during the dead time caused by 221Fr decay events. The overall counting efficiency of the TDCR system of PTB was found to be about 700% (depending on the degree of chemical quenching) and the relative standard uncertainty of the activity concentration was found to be about 0.23%. The determined activity concentration was compared with the outcome of alpha spectrometry under defined solid angle and excellent agreement was found. The TDCR efficiency calculations can be easily adapted to activity determinations of 225Ra or 225Ac in equilibrium with their progenies. - Highlights: • The activity of a 229Th solution was determined by means of TDCR measurements. • The relative standard uncertainty was found to be 0.23%. • A new portable mini-TDCR system was successfully tested. • Results are in good agreement with the outcome from alpha spectrometry

  5. Antioxidant and gene expression responses of Eisenia fetida following repeated exposure to BDE209 and Pb in a soil-earthworm system.

    Hu, Shuangqing; Zhang, Wei; Li, Jing; Lin, Kuangfei; Ji, Rong

    2016-06-15

    This study first adopted repeated treatment model to investigate stress responses in earthworms (Eisenia fetida) following exposure to decabromodiphenyl ether (BDE209) and lead (Pb), which are the mainly co-existed contaminants at e-waste recycling sites. We evaluated the impacts of BDE209-Pb on antioxidative enzyme (superoxide dismutase, SOD; catalase, CAT) activities, malondialdehyde (MDA) contents and transcriptional levels of three target genes (SOD, CAT and Hsp70), and further explored the relationships among these biomarkers. Results demonstrated that almost all the parameters were generally induced and the responses followed certain dose-effect relationships. Compared to the controls, a significant (P0.64). The observations could provide important information of ecotoxicological effects of BDE209-Pb in a soil-earthworm system as well as the mechanism of antioxidant defense. PMID:26971217

  6. 18Ne Excited States Two-Proton Decay

    de Napoli, M.; Rapisarda, E.; Raciti, G.; Cardella, G.; Amorini, F.; Giacoppo, F.; Sfienti, C.

    2008-04-01

    Two-proton radioactivity studies have been performed on excited states of 18Ne produced by 20Ne fragmentation at the FRS of the Laboratori Nazionali del Sud and excited via Coulomb excitation on a 209Pb target. The 18Ne levels decay has been studied by complete kinematical reconstruction. In spite of the low statistic, the energy and angular correlations of the emitted proton pairs indicate the presence of 2He emission toghether with the democratic decay.

  7. On the direct nucleon decay of high-spin subbarrier single-particle states in near-magic nuclei

    Chekomazov, G. A.; Urin, M. H.

    1996-01-01

    The description of the direct nucleon decay of high-spin subbarrier one-particle states in near-magic nuclei is attempted using a simple optical model and the simplest version of the coupled-channel approach. The branching ratios for the direct decay of the several single-neutron states in $^{209}Pb$ and $^{91}Zr$ to the ground state and to the low-lying collective states of $^{208}Pb$ and $^{90}Zr$, respectively, are evaluated. Results are compared with recent experimental data.

  8. Double-magic nature of 132Sn and 208Pb through lifetime and cross-section measurements.

    Allmond, J M; Stuchbery, A E; Beene, J R; Galindo-Uribarri, A; Liang, J F; Padilla-Rodal, E; Radford, D C; Varner, R L; Ayres, A; Batchelder, J C; Bey, A; Bingham, C R; Howard, M E; Jones, K L; Manning, B; Mueller, P E; Nesaraja, C D; Pain, S D; Peters, W A; Ratkiewicz, A; Schmitt, K T; Shapira, D; Smith, M S; Stone, N J; Stracener, D W; Yu, C-H

    2014-05-01

    Single-neutron states in (133)Sn and (209)Pb, which are analogous to single-electron states outside of closed atomic shells in alkali metals, were populated by the ((9)Be, (8)Be) one-neutron transfer reaction in inverse kinematics using particle-γ coincidence spectroscopy. In addition, the s(1/2) single-neutron hole-state candidate in (131)Sn was populated by ((9)Be, (10)Be). Doubly closed-shell (132)Sn (radioactive) and (208)Pb (stable) beams were used at sub-Coulomb barrier energies of 3 MeV per nucleon. Level energies, γ-ray transitions, absolute cross sections, spectroscopic factors, asymptotic normalization coefficients, and excited-state lifetimes are reported and compared with shell-model expectations. The results include a new transition and precise level energy for the 3p(1/2) candidate in (133)Sn, new absolute cross sections for the 1h(9/2) candidate in (133)Sn and 3s(1/2) candidate in (131)Sn, and new lifetimes for excited states in (133)Sn and (209)Pb. This is the first report on excited-state lifetimes of (133)Sn, which allow for a unique test of the nuclear shell model and (132)Sn double-shell closure. PMID:24836240

  9. Elastic and inelastic scattering of polarized protons from lead-206 and lead-208 near isobaric analog resonances

    Excitation functions have been measured for elastic scattering of polarized protons from 206Pb and 208Pb, and for inelastic scattering to collective states in 206Pb (2+, 0.8033 MeV; 3-, 2.647 MeV) and 208Pb (3-, 2.6145 MeV). Both differential cross sections and analyzing powers were measured at theta/sub lab/ = 1200, 1350, 1500, and 1650, for E/sub p/ = 14.25 to 18 MeV. Fits to the excitation-function data were obtained using scattering amplitudes consisting of sums of resonant and non-resonant parts. The resonances are the isobaric analogs (IARs) of 7 low-lying states in 209Pb and 35 in 207Pb. The fits to the elastic-scattering data are excellent; for the inelastic scattering the fit is very good for the 2+ state but only fair for the 3- states. For each IAR, the energy, the total width, and the partial width and mixing phase in each channel were obtained. Also, new spin assignments were made for a number of parent states in 207Pb. The theory of Bund and Blair was used to find the spectroscopic amplitudes, which provide information on the wave functions for the parent states in 207Pb and 209Pb and for the 3- states in 206Pb and 208Pb. These spectroscopic amplitudes were then checked for internal consistency and compared with the results of other experiments and with theoretical predictions

  10. Precise Study of Fine Structure in $^{14}$C Emission from $^{223}$Ra

    2002-01-01

    We request 10 shifts in two sessions of beam time at ISOLDE for the production of a $^{223}$Ra source. This source will be used with the superconducting spectrometer SOLENO at Orsay for a precise measurement (good statistics and energy resolution) of the fine stucture in the energy spectrum of $^{14}$C nuclei emitted by $^{223}$Ra, discovered at Orsay in July 1989. The measurement will be devoted to carry out the hindrance factors of the transitions to 15$\\!^-\\!$/2$\\,$ (1.423 MeV) and 5$\\!^+\\!$/2$\\,$ (1.567 MeV) excited states of $^{209}$Pb, which present a particular interest for obtaining spectroscopic information and testing nuclear models.

  11. Octupole transitions in the 208Pb region

    The 208Pb region is characterised by the existence of collective octupole states. Here we populated such states in 208Pb + 208Pb deep-inelastic reactions. γ-ray angular distribution measurements were used to infer the octupole character of several E3 transitions. The octupole character of the 2318 keV 17− → 14+ in 208Pb, 2485 keV 19/2− → 13/2+ in 207Pb, 2419 keV 15/2− → 9/2+ in 209Pb and 2465 keV 17/2+ → 11/2− in 207Tl transitions was demonstrated for the first time. In addition, shell model calculations were performed using two different sets of two-body matrix elements. Their predictions were compared with emphasis on collective octupole states

  12. (d,p) reactions on 124Sn, 130Te, 138Ba, 140Ce, 142Nd, and 208Pb below and near the Coulomb barrier

    The reactions 124Sn(d,p)125Sn, 130Te(d,p)131Te, 138Ba(d,p)139Ba, 140Ce(d,p)141Ce, 142Nd(d,p)143Nd, and 208Pb(d,p)209Pb have been investigated by measuring the differential cross sections of the (d,p) reactions and of the elastic scattering of deuterons at various incident energies below and near the Coulomb barrier. Using scattering potentials which describe the elastic scattering of the particles in the entrance and exit channels, reduced normalizations of 40 final states have been determined which are nearly independent of the uncertainties due to the ambiguities of optical potentials. The experimental errors are 8% on the average. In the energy region studied the expected constancy of derived spectroscopic factors is demonstrated

  13. Neutron halos in the excited states for N=127 isotones

    SUN Qin; GUO Jian-You

    2009-01-01

    Properties of the ground states and the excited states of N=127 isotones are investigated by using the nonlinear relativistic mean field theory with the interactions PK1. By analyzing the rms of proton and neutron, the single particle energies of valence nucleon and the density distributions of neutron, proton and the last neutron, it can be found that there exists a neutron halo in the excited states of 3d5/2, 4s1/2 and 3d3/2 in 209Pb. It is also predicted that there exists a neutron halo in the excited states of 3d5/2, 4s1/2 and 3d3/2 in 207Hg, 208Tl, 210Bi and 211Po.

  14. Discovery of 109Xe and 105Te: Superallowed α Decay near Doubly Magic 100Sn

    Two new α emitters 109Xe and 105Te were identified through the observation of the 109Xe→105Te→101Sn α-decay chain. The 109Xe nuclei were produced in the fusion-evaporation reaction 54Fe(58Ni,3n)109Xe and studied using the Recoil Mass Spectrometer at the Holifield Radioactive Ion Beam Facility. Two transitions at Eα=4062±7 keV and Eα=3918±9 keV were interpreted as the l=2 and l=0 transitions from the 7/2+ ground state in 109Xe (T1/2=13±2 ms) to the 5/2+ ground state and a 7/2+ excited state, located at 150±13 keV in 105Te. The observation of the subsequent decay of 105Te marks the discovery of the lightest known α-decaying nucleus. The measured transition energy Eα=4703±5 keV and half-life T1/2=620±70 ns were used to determine the reduced α-decay width δ2. The ratio δ105Te2/δ213Po2 of ∼3 indicates a superallowed character of the α emission from 105Te

  15. An analytical model to calculate absorbed fractions for internal dosimetry with alpha, beta and gamma emitters

    Ernesto Amato

    2014-03-01

    Full Text Available We developed a general model for the calculation of absorbed fractions in ellipsoidal volumes of soft tissue uniformly filled with alpha, beta and gamma emitting radionuclides. The approach exploited Monte Carlo simulations with the Geant4 code to determine absorbed fractions in ellipsoids characterized by a wide range of dimensions and ellipticities, for monoenergetic emissions of each radiation type. The so-obtained absorbed fractions were put in an analytical relationship with the 'generalized radius', calculated as 3V/S, where V is the ellipsoid volume and S its surface. Radiation-specific parametric functions were obtained in order to calculate the absorbed fraction of a given radiation in a generic ellipsoidal volume. The dose from a generic radionuclide can be calculated through a process of summation and integration over the whole radionuclide emission spectrum, profitably implemented in an electronic spreadsheet. We compared the results of our analytical calculation approach with those obtained from the OLINDA/EXM computer software, finding a good agreement in a wide range of sphere radii, for the high-energy pure beta emitter 90Y, the commonly employed beta-gamma emitter 131I, and the pure alpha emitter 213Po. The generality of our approach makes it useful an easy to implement in clinical dosimetry calculations as well as in radiation safety estimations when doses from internal radionuclide uptake are to be taken into account.

  16. Effects of Nonlocality on Transfer Reactions

    Titus, Luke J

    2016-01-01

    We solved the nonlocal scattering and bound state equations using the Perey-Buck type interaction, and compared to local equivalent calculations. Using the distorted wave Born approximation we construct the T-matrix for (p,d) transfer on 17O, 41Ca, 49Ca, 127Sn, 133Sn, and 209Pb at 20 and 50 MeV. Additionally we studied (p,d) reactions on 40Ca using the the nonlocal dispersive optical model. We have also included nonlocality consistently into the adiabatic distorted wave approximation and have investigated the effects of nonlocality on on (d,p) transfer reactions for deuterons impinged on 16O, 40Ca, 48Ca, 126Sn, 132Sn, 208Pb at 10, 20, and 50 MeV. We found that for bound states the Perry corrected wave functions resulting from the local equation agreed well with that from the nonlocal equation in the interior region, but discrepancies were found in the surface and peripheral regions. Overall, the Perey correction factor was adequate for scattering states, with the exception for a few partial waves. Nonlocality...

  17. Meson-Exchange Enhancement of First-Forbidden $\\beta$-Transitions in the Lead Region

    Delaure, B J P; Severijns, N

    2002-01-01

    Both on-line and off-line low temperature nuclear orientation is used to measure the $\\beta$-asymmetry parameter for the first-forbidden g.s. $\\rightarrow$~g.s. $\\beta$-transitions of $^{205}$Hg, $^{207,209}$Tl, $^{209}$Pb and $^{213}$Bi. From this, the ratio of the rank-zero and the rank-one strengths in these decays can be deduced, with the rank of a $\\beta$-transition being defined as the total angular momentum of the lepton system. Combining this result with the experimental ${ft}$-values yields for the first time a purely experimental determination of the rank-zero contribution in these $\\Delta$ J = 0 first-forbidden transitions. This provides an independent check of the large enhancement (of about 100% over the impulse approximation) of the rank-zero matrix element of $\\gamma_{5} $, caused by meson exchange currents (MEC), which was recently obtained from a comparison of calculated first-forbidden $\\beta$-decay rates with experimentally observed values for nuclei in the lead region (A = 205-212). Measur...

  18. A walk-free centroid method for lifetime measurements with pulsed beams

    A delayed-coincidence lifetime measurement method based on a comparison of walk-free centroids of time spectra is presented. The time is measured between the cyclotron RF signal and the pulse from a plastic scintillation detector followed by a fixed energy selection. The events to be time-analyzed are selected from the associated charge-particle spectrum of a silicon detector which is operated in coincidence with the scintillator, i.e., independently of the formation of the signal containing the time information. With this technique, with the micropulse FWHM of typically 500 to 700 ps, half-lives down to the 10 ps region can be measured. The following half-lives are obtained with the new method: 160+-6 ps for the 2032 keV level in 209Pb; 45+-10 ps and 160+-20 ps for the 1756.8 keV (02+) and 2027.3 keV (03+) levels in 116Sn, respectively. (author)

  19. Numerical and analytical super-asymmetric fission model for exotic cluster decays. Chapter 17

    One has to keep in touch with any experimental new finding in the field, trying to improve the fundamental understanding and description of various decay modes within different theoretical approaches. As an example, new experimental results are awaited in the island of cluster emitters above Sn, particularly 12C radioactivity of 114Ba, from which different nuclear properties of intermediate mass proton-rich nuclei can be determined. Also a new experiment on the fine structure of 14C decay of 223Ra should determine the hindrance factor of the transition to the fourth (1/2+) excited state of the daughter 209Pb. At present it is not known whether this transition is hindered or not. The fission theory of the fine structure, and more generally of cluster emission from nuclei with odd number of protons and/or neutrons, has to be elaborated up to the point of predicting some other interesting cases which could be measured in the near future. In the same time one has to think about the cold fission of heavy nuclei which can be experimentally studied with the technique of large arrays of gamma ray detectors already applied to the study of spontaneous fission of 252Cf in Oak Ridge. The best candidate for a cold fission process would certainly be 264Fm, decaying into two double magic 132Sn nuclei. Some other nuclei (perhaps longer lived) will be recommended to be measured. Interesting connections with the fission of atomic clusters could be made, by trying to see how far can be extrapolated to this new field of research the knowledge of nuclear phenomena

  20. Lead isotopes and trace metal ratios of aerosols as tracers of Pb pollution sources in Kanpur, India

    Sen, Indra; Bizimis, Michael; Tripathi, Sachchida; Paul, Debajyoti; Tyagi, Swati; Sengupta, Deep

    2015-04-01

    The anthropogenic flux of Pb in the Earth's surface is almost an order of magnitude higher than its corresponding natural flux [1]. Identifying the sources and pathways of anthropogenic Pb in environment is important because Pb toxicity is known to have adverse effects on human health. Pb pollution sources for America, Europe, and China are well documented. However, sources of atmospheric Pb are unknown in India, particularly after leaded gasoline was phased out in 2000. India has a developing economy with a rapidly emerging automobile and high temperature industry, and anthropogenic Pb emission is expected to rise in the next decade. In this study, we report on the Pb- isotope compositions and trace metal ratios of airborne particulates collected in Kanpur, an industrial city in northern India. The Pb concentration in the airborne particulate matter varies between 14-216 ng/m3, while the other heavy metals vary by factor of 10 or less, e.g. Cd=0.3-3 ng/m3, As=0.4-3.5 ng/m3, Zn=36-161 ng/m3, and Cu=3-22 ng/m3. The 206Pb/207Pb, 208Pb/206Pb, and 208Pb/207Pb vary between 1.112 - 1.129, 2.123-2.141, and 2.409-2.424 respectively, and are highly correlated with each other (R2>0.9). Pb isotopes and trace metal data reveals that coal combustion is the major source of anthropogenic Pb in the atmosphere, with limited contribution from mining and smelting processes. We further conclude that combination of Pb isotope ratios and V/Pb ratios are powerful tracers for Pb source apportionment studies, which is otherwise difficult to differentiate based only on Pb systematics [1] Sen and Peucker-Ehrenbrink (2012), Environ. Sci. Technol.(46), 8601-8609

  1. Evaluation of sample pretreatment methods for analysis of Polonium isotopes in herbal medicine

    Ayurvedic medicines are widely consumed by Indian population both for treatment and good health Ayurvedic medicines are used in various forms like infusions, decoctions, powder, tablets, fermented decoction (Arishta) etc. Arishtas are prepared using plant extracts soaked in sugar or jaggery and are generally consume on regular basis for good health. Hence an effort was made to analyse the natural radioactivity in the Ayurvedic Arishtas. 213Po is an important naturally occurring radionuclide that volatilizes beyond 150℃. Hence adequate care is needed during sample pretreatment step. Both physical (freeze-drying, open vessel evaporation and microwave digestion) and chemical (digestion using various mineral acids like aqua regia, Con. HNO3, H2SO4 and oxidizing agents like H2O2 and HClO4) pretreatment procedures were adopted. After the initial sample treatment polonium radionuclide was pre-concentrated using calcium phosphate co-precipitation. Calcium phosphate precipitate was dissolved in 150 ml of 0.5M HCI solution with approximately 1 g of ascorbic acid for auto deposition of Polonium on silver planchette for 3 hours at 90℃ on a rotary hot plate. The sample sources were counted in calibrated alpha spectrometer with 450 mm2 low-back-ground PIPS detector interfaced with ECIL MCA. The spectrum analysis was done using PHAST Software. 209Po tracer, at low levels was added to the samples for assessing the radiochemical recovery. The recovery ranged between 18-83 %. The lowest recovery was obtained for the samples that were processed by open vessel digestion with HNO3 + HCIO4 + H2O2. The highest recover was for those samples that were freeze dried and subjected to HNO3 + HCIO4 + H2O2 acid digestion at 90℃ for 8 hours. 210Po concentration in a few samples varied between 0.3-3.5 mBq/L. The paper presents the results of radiochemical recoveries for different pretreatment methods and also the 210Po content in the ayurvedic arishtas. (author)

  2. High thermoelectric figure of merit in nanocrystalline polyaniline at low temperatures

    Nath, Chandrani; Kumar, Ashok, E-mail: ask@tezu.ernet.in, E-mail: okram@csr.res.in [Materials Research Laboratory, Department of Physics, Tezpur University, Tezpur 784 028 (India); Kuo, Yung-Kang [Department of Physics, National Dong-Hwa University, Hualien 974, Taiwan (China); Okram, Gunadhor Singh, E-mail: ask@tezu.ernet.in, E-mail: okram@csr.res.in [Electrical Transport Laboratory, UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452 017 (India)

    2014-09-29

    Thermoelectric coolers with figure of merit (ZT) close to unity at low temperatures are the need of the hour with new advances in high temperature superconductors, superconducting microelectronic circuits, quantum computers, and photonics. Here, we demonstrate that the conducting polymer polyaniline (Pani) doped with camphor sulfonic acid synthesized in semi-crystalline nanostructures, possesses a giant Seebeck effect at low temperatures. The resulting enormously large Seebeck coefficient (up to 0.6 V/K) combined with an intrinsically low electrical conductivity and thermal conductivity give rise to a ZT = 0.77 at 45 K and ZT = 2.17 at 17 K.

  3. Direct measurement of tritium production rate in LiPb with removed parasitic activities: Preliminary experiments

    Liquid scintillation (LS) technique applied to direct measurement of tritium activity produced in LiPb eutectic in Frascati HCLL TBM mock-up neutronic experiment has been tested so far in the case of LS measurement after long period since irradiation. LiPb samples irradiated in neutron filed show, except of tritium, meaningful activity of other radioisotopes (parasitic). Parasitic activity, mainly from isotopes of lead (209Pb, 204mPb, 203Pb) calculated with the use of FISPACT, exceeds ca 5 times tritium activity 1.4 h after irradiation. We propose to remove disturbing radioisotopes in a chemical way to avoid long “cooling” of the irradiated samples before tritium measurement. Samples (1 g of LiPb) irradiated in reactor fast neutron flux were diluted and metallic cations removed by chemical precipitation. For this purpose we used: potassium iodide (KJ), strontium chloride (SrCl2), APDC (C5H8NS2·NH4), NaDDTC (C5H10NNaS2·3H2O), and PAN (C15H11N3O). Precipitation procedure in each case lasted ca 5–25 min, and the following filtration next 10–20 min. In each filtrate (ca 120 ml) we measured Pb concentration in total reflection X-ray fluorescence (TXRF) analyzer and parasitic activity (left after 21-day “cooling”) applying HPGe gamma spectrometer. Pb cations precipitated by SrCl2 and than by PAN lowered activity of Pb isotopes to less than 1% of the initial tritium activity. Another combination of reagents: NaDDTC followed by SrCl2 in a single and double step filtration reduced Pb concentration 102 and 104 times, respectively. Reduction of this order allows tritium radiometric measurement ca 3 h after irradiation with acceptable accuracy. This time can be shortened by applying correction for decay of known parasitic activity. Input of 76As and other less abundant radioisotopes can be eliminated using high purity LiPb. Tritium activity of the filtrates measured in LS spectrometer showed no dependence upon used reagent being, within measurement error, the

  4. Hydrogen adsorption on zirconium carbide and its alloys with rhenium

    Hydrogen adsorption on zirconium carbide and ZrC-Re84at%, ZrC-Re21.7at% alloys was studied by the themodesorption method. Hydrogen thermodesorption curves were taken after various exposures, at the temperature increase from 300 up to 1450 K, or up to 2500 K. Determined were the initial hydrogen adhesion coefficient of S0=0.03+-0.02, and desorption temperature of 750-1000 K. The initial hydrogen coefficient of adhesion to carbides is less than to metals of their composition. Thermoemission and adsorption properties of two-phase alloys are close to those for ZrC. The soluted hydrogen deposition proceeded in zirconium carbide at 750-1500 K slower than thermodesorption

  5. Tunnel magnetoresistance in epitaxially grown magnetic tunnel junctions using Heusler alloy electrode and MgO barrier

    Tsunegi, S.; Sakuraba, Y.; Oogane, M.; Telling, N. D.; Shelford, L. R.; Arenholz, E.; van der Laan, G.; Hicken, R. J.; Takanashi, K.; Ando, Y.

    2009-07-01

    Epitaxially grown magnetic tunnel junctions (MTJs) with a stacking structure of Co{sub 2}MnSi/MgO/CoFe were fabricated. Their tunnel magnetoresistance (TMR) effects were investigated. The TMR ratio and tunnelling conductance characteristics of MTJs were considerably different between those with an MgO barrier prepared using sputtering (SP-MTJ) and those prepared using EB evaporation (EB-MTJ). The EB-MTJ exhibited a very large TMR ratio of 217% at room temperature and 753% at 2 K. The bias voltage dependence of the tunnelling conductance in the parallel magnetic configuration for the EB-MTJ suggests that the observed large TMR ratio at RT results from the coherent tunnelling process through the crystalline MgO barrier. The tunnelling conductance in the anti-parallel magnetic configuration suggests that the large temperature dependence of the TMR ratio results from the inelastic spin-flip tunnelling process.

  6. Synthesis and Antiproliferative Activity of Steroidal Thiosemicarbazone Platinum (Pt(II)) Complexes.

    Huang, Yanmin; Kong, Erbin; Gan, Chunfang; Liu, Zhiping; Lin, Qifu; Cui, Jianguo

    2015-01-01

    Steroidal compounds exhibit particular physiological activities. In this paper, some steroidal thiosemicarbazones platinum (Pt(II)) complexes were synthesized by the condensation of steroidal ketones with thiosemicarbazide using estrone, chenodeoxycholic acid, and 7-deoxycholic acid as starting materials and complexation of steroidal thiosesemicarbazones with Pt(II). The complexes were characterized by IR, NMR, and MS, and their antiproliferative activities were evaluated. The results showed that some steroidal thiosemicarbazones platinum (Pt(II)) complexes displayed moderate cytotoxicity to HeLa and Bel-7404 cells. Thereinto, complex 6 showed an excellent inhibited selectivity to HeLa cells with an IC50 value of 9.2 μM and SI value of 21.7. At the same time, all compounds were almost inactive to HEK293T (normal kidney epithelial cells). The information obtained from the studies may be useful for the design of novel chemotherapeutic drugs. PMID:26635511

  7. Synthesis and Antiproliferative Activity of Steroidal Thiosemicarbazone Platinum (Pt(II Complexes

    Yanmin Huang

    2015-01-01

    Full Text Available Steroidal compounds exhibit particular physiological activities. In this paper, some steroidal thiosemicarbazones platinum (Pt(II complexes were synthesized by the condensation of steroidal ketones with thiosemicarbazide using estrone, chenodeoxycholic acid, and 7-deoxycholic acid as starting materials and complexation of steroidal thiosesemicarbazones with Pt(II. The complexes were characterized by IR, NMR, and MS, and their antiproliferative activities were evaluated. The results showed that some steroidal thiosemicarbazones platinum (Pt(II complexes displayed moderate cytotoxicity to HeLa and Bel-7404 cells. Thereinto, complex 6 showed an excellent inhibited selectivity to HeLa cells with an IC50 value of 9.2 μM and SI value of 21.7. At the same time, all compounds were almost inactive to HEK293T (normal kidney epithelial cells. The information obtained from the studies may be useful for the design of novel chemotherapeutic drugs.

  8. Keck and VLT Observations of Super-damped Lyman-alpha Absorbers at z=2=2.5: Constraints on Chemical Compositions and Physical Conditions

    Kulkarni, Varsha P; Morrison, Sean; Peroux, Celine; Quiret, Samuel; York, Donald G

    2015-01-01

    We report Keck/ESI and VLT/UVES observations of three super-damped Lyman-alpha quasar absorbers with H I column densities log N(HI) >= 21.7 at redshifts z=2-2.5. All three absorbers show similar metallicities (-1.3 to -1.5 dex), and dust depletion of Fe, Ni, and Mn. Two of the absorbers show supersolar [S/Zn] and [Si/Zn]. We combine our results with those for other DLAs to examine trends between N(HI), metallicity, dust depletion. A larger fraction of the super-DLAs lie close to or above the line [X/H]=20.59-log N(HI) in the metallicity vs. N(HI) plot, compared to the less gas-rich DLAs, suggesting that super-DLAs are more likely to be rich in molecules. Unfortunately, our data for Q0230-0334 and Q0743+1421 do not cover H2 absorption lines. For Q1418+0718, some H2 lines are covered, but not detected. CO is not detected in any of our absorbers. For DLAs with log N(HI) 21.7 may have somewhat narrower velocity dispersions delta v_90 than the less gas-rich DLAs, and may arise in cooler and/or less turbulent gas.

  9. Radioisotope space power generator annual report, July 1, 1974--June 30, 1975

    The Isotec Technology Program for FY-75 concentrated on materials development efforts in two areas: TPM-217 P-type material and SiGe technology. TPM-217 P-type material is a 3M proprietary thermoelectric material whose principal components are Cu, Ag, and Se. The usefulness of TPM-217 P-type selenide in thermoelectric converters depends on its dimensional, electrical, and thermal stability at high temperature and its compatibility with other converter component materials in a low-pressure environment. Experimental efforts were directed toward determining (1) the vapor species above TPM-217 from 7000 to 11000C, (2) the weight loss rate for TPM-217 at 9000C in vacuo, and (3) the stability of TPM-217 material in contact with Mo, Fe, 316 stainless steel, and pyrocarbon. The Si-Ge program is a continuation of the experimental work performed during FY-74. The development of coatings to suppress the vaporization of SiMo and SiGe continued. Techniques for applying ion-plated and chemical-vapor-deposited coatings of Si3N4 and (Si,Al)N alloys on SiMo were examined. Methods of controlling morphology and the chemical composition of these coatings were developed. Rates of vaporization for coated samples at 11000C were measured

  10. Analysis of epitopes on dengue virus envelope protein recognized by monoclonal antibodies and polyclonal human sera by a high throughput assay.

    Hong-En Lin

    2012-01-01

    Full Text Available BACKGROUND: The envelope (E protein of dengue virus (DENV is the major target of neutralizing antibodies and vaccine development. While previous studies on domain III or domain I/II alone have reported several epitopes of monoclonal antibodies (mAbs against DENV E protein, the possibility of interdomain epitopes and the relationship between epitopes and neutralizing potency remain largely unexplored. METHODOLOGY/PRINCIPAL FINDINGS: We developed a dot blot assay by using 67 alanine mutants of predicted surface-exposed E residues as a systematic approach to identify epitopes recognized by mAbs and polyclonal sera, and confirmed our findings using a capture-ELISA assay. Of the 12 mouse mAbs tested, three recognized a novel epitope involving residues (Q211, D215, P217 at the central interface of domain II, and three recognized residues at both domain III and the lateral ridge of domain II, suggesting a more frequent presence of interdomain epitopes than previously appreciated. Compared with mAbs generated by traditional protocols, the potent neutralizing mAbs generated by a new protocol recognized multiple residues in A strand or residues in C strand/CC' loop of DENV2 and DENV1, and multiple residues in BC loop and residues in DE loop, EF loop/F strand or G strand of DENV1. The predominant epitopes of anti-E antibodies in polyclonal sera were found to include both fusion loop and non-fusion residues in the same or adjacent monomer. CONCLUSIONS/SIGNIFICANCE: Our analyses have implications for epitope-specific diagnostics and epitope-based dengue vaccines. This high throughput method has tremendous application for mapping both intra and interdomain epitopes recognized by human mAbs and polyclonal sera, which would further our understanding of humoral immune responses to DENV at the epitope level.

  11. A study on the isolation period of patients with metastatic thyroid cancer treated by 131I according to a new guideline

    In Japan, a new guideline for the release of patients administered 131I was issued by the Ministry of Welfare on June, 1998: The dose rate is under 30 μSv/h at 1 m or the activity in the body is under 500 MBq. This study was designed to set the appropriate isolation period enough to satisfy these limits. A total of 28 patients with the history of total thyroidectomy and metastasis were selected for this study. In these patients, 28 patients were treated with oral administration of 3.7 GBq of Na131I (72 times), and one of 28 patients was once treated with 5.55 GBq of Na131I. Two of them were also received a total of 4 courses of a split dose therapy of 3.7 GBq of Na131I (740 MBq once a week for 5 consecutive weeks = one course). Measurements of the external exposure dose (μSv/h) at 1 m and the urinary excretory radioactivity (MBq) were performed at various times. There was a good correlation of the external exposure dose between standing (x μSv/h) and sitting (y μSv/h) postures (y=0.99x+0.406, r=0.99, p131I, the mean and S.D. values of the external exposure dose (μSV/h) changed as follow: After 6 hr, 168±40; 24 hr, 52±23; 48 hr, 20±15; 72 hr, 10±9; and 96 hr, 8±9. The percentages of the patients satisfied the new guideline were as follow; 21.7% at 24 hr, 81.2% at 48 hr and 100% after 72 hr. Therefore the 3-day isolation is sufficient for the patients administered 3.7 GBq of Na131I. (author)

  12. Activ C cervical disc replacement for myelopathy

    L McGonagle

    2011-01-01

    Full Text Available Background: Cervical disc replacement is becoming an increasingly popular treatment option for cervical myelopathy. It retains motion at the affected segment, unlike anterior cervical discectomy and fusion. The aim of this study is to assess the outcomes of a series of patients who underwent Activ C disc replacement for cervical myelopathy. Materials and Methods: A series of patients at the above Trust with clinical and radiological evidence of cervical myelopathy who were suitable for cervical disc replacement from 2007 to 2009 were included. Implants were inserted by one of two consultant surgeons {IMS, MO′M}. Patients were assessed preoperatively and at six, 12 and 24 months, postoperatively, with a visual analogue score (VAS for neck and arm pain severity and frequency, the Neck Disability Index questionnaire (NDI and the Centre for Epidemiologic Studies Depression questionnaire (CES-D. Results: Ten patients underwent surgery between May 2007 and July 2009, 6 women, and 4 men. Average age was 54 years (40-64. Disc levels replaced were: four at C4-5; eight at C5-6; seven at C6-7. Three patients had one disc replaced, five patients had two discs replaced, and two patients had three discs replaced. The VAS for neck pain improved from 5.9 pre-operatively to 1.4-24 months postoperatively and the VAS arm pain improved from 5.4 to 2.6. The NDI improved from 51% preoperatively to 26.8% at 24 months postoperatively. The CES-D showed a slight increase from 19.5 preoperatively to 21.7 at 24 months, postoperatively. Conclusion: Cervical decompression and disc replacement improves pain and function in patients with cervical myelopathy. This benefit is maintained at 24 months post op, with no cases requiring revision.

  13. A representation of the Sm-Co-Zr-Cu-Fe quinary system: a tool for optimisation of 2/17 permanent magnets

    In order to optimise the elaboration process of Sm2Co17 type magnets, the boundary of the single-phase domain at 1150 C and of the two-phase domain involving the 1/5 and the 2/17 at 850 C must be known. The knowledge of solid-liquid equilibria is also needed in order to avoid formation of other phases during sintering. It was then necessary to investigate phase equilibria in the Sm-Co-Zr-Cu-Fe system. However, since the variability of a such system under isobaric and isothermal conditions is four, the classic graphical representation can not be used. The presented part of the work concerns the region of interest near 1150 C. A specific approach of the quinary system is developed. It starts from the Sm-Co binary system, then the Sm-Co-Zr ternary system has been investigated: 1150 C isothermal section has been drawn for high Co contents and special attention has been paid to in the structural modification induced by Zr addition. Based on our knowledge of the ternary system, the Sm-Co-Zr-Cu quaternary one has been studied; an isothermal section has been drawn for a Cu concentration of 4 at.%. Finally a representation of the 1150 C single-phase domain in the quinary system Sm-Co-Zr-Cu-Fe is proposed. For this purpose, a method consisting of a two-dimensional projection of the domain coupled with a three-dimensional one is applied. This representation makes possible to predict if a quinary alloy is single-phased at 1150 C or not. Magnetic behaviour of alloys is shown. This easy to read, easy to use representation appears a good tool to optimise the 2/17-type permanent magnets. (orig.)

  14. Assessment of herbicidal toxicity based on non-destructive measurement of local chlorophyll content in photoautotrophic hairy roots.

    Ninomiya, Kazuaki; Oogami, Yoshihiro; Kino-Oka, Masahiro; Taya, Masahito

    2003-01-01

    Changes in local chlorophyll (Chl) content in photoautotrophic hairy roots of pak-bung (Ipomoea aquatica) were evaluated at incident light intensities of I=11 and 22 W/m2 by non-destructive measurement of the pigment based on color image analysis. Upon addition of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), 1-1'-dimethyl-4,4'-bipyridylium dichloride (paraquat) and 2,4-dichlorophenoxyacetic acid (2,4-D) to the medium at the median effective concentrations (0.40, 0.37 and 0.45 micromol/dm3 for DCMU, paraquat and 2,4-D, respectively), the roots showed different Chl pigmentation responses when the Chl content was measured at longitudinal lengths of l0=2.5 mm (Chl accumulation position) and l(0)=35 mm (Chl saturation position) under light irradiation. Chl accumulation index (beta) and Chl degradation index (gamma) were determined from the changes in Chl content at l0=2.5 and 35 mm, respectively, during the cultures for 96 h: beta=0% (DCMU), 93.6% (paraquat) and 93.8% (2,4-D), and gamma=98.4% (DCMU), 282% (paraquat) and 86.5% (2,4-D) at I=22 W/m2. Moreover, the bioassay system with the hairy roots was applied to the evaluation of a model sample of field water. The values of beta and gamma for the field water were determined, respectively, to be 105% and 217% at I=22 W/m2, from which the field water tested was judged to be a "paraquat-like" toxicant against the roots. PMID:16233403

  15. A new structure of p-GaN/InGaN heterojunction to enhance hole injection for blue GaN-based LEDs

    Lin, Zhiting; Wang, Haiyan; Lin, Yunhao; Yang, Meijuan; Li, Guoqiang; Xu, Bingshe

    2016-07-01

    A new structure of p-GaN/InGaN heterojunction has been proposed to enhance hole injection for blue GaN-based light-emitting diodes (LEDs). It is demonstrated by the simulation results that a p-GaN (50 nm)/In0.05Ga0.95N (150 nm) heterojunction can make a 25% and 10% increment of hole and electron concentration in the active region, respectively, finally resulting in a 55% improvement on the LED’s radiative recombination intensity. The simulation also reveals that the efficiency droop is alleviated from 32.9% to 21.7% at the current density of 100 A cm‑2. The enhanced hole injection is mainly attributed to the increased average background hole concentration of the area between the p-AlGaN electron blocking layer (EBL) to the p-GaN/InGaN heterojunction. The increasing potential barrier of the conduction band, resulting from the introduction of p-GaN/InGaN heterojunction, would also weaken electron leakage and is favorable to the LED’s luminous performance. The experimental results show that the wall-plug efficiency (WPE) of the p-GaN/InGaN LED increases by 26.0% at the injection current of 75 mA, in spite of the increasing electric resistance, which impairs the improvement of the LED’s performance from the enhanced hole injection. The structure of the p-GaN/InGaN heterojunction is novel in the field of p-type region design, and is a simple but effective way to promote the LED’s performance, which is very promising for application in further high-performance LED fabrication.

  16. Keck and VLT Observations of Super-Damped Lyman-Alpha Absorbers at z 2- 2.5: Constraints on Chemical Compositions and Physical Conditions

    Kulkarni, Varsha P.; Som, Debopam; Morrison, Sean; Péroux, Celine; Quiret, Samuel; York, Donald G.

    2015-12-01

    We report Keck/Echellette Spectrograph and Imager and Very Large Telescope/Ultraviolet-Visual Echelle Spectrograph observations of three super-damped Lyα quasar absorbers with H i column densities log NH i ≥ 21.7 at redshifts 2 ≲ z ≲ 2.5. All three absorbers show similar metallicities (˜-1.3 to -1.5 dex), and dust depletion of Fe, Ni, and Mn. Two of the absorbers show supersolar [S/Zn] and [Si/Zn]. We combine our results with those for other damped Lyα a absorbers (DLAs) to examine trends between NH i, metallicity, and dust depletion. A larger fraction of the super-DLAs lie close to or above the line [X/H] = 20.59 - log NH i in the metallicity versus NH i plot, compared to the less gas-rich DLAs, suggesting that super-DLAs are more likely to be rich in molecules. Unfortunately, our data for Q0230-0334 and Q0743+1421 do not cover H2 absorption lines. For Q1418+0718, some H2 lines are covered, but not detected. CO is not detected in any of our absorbers. For DLAs with log NH i 21.7 may have somewhat narrower velocity dispersions Δv90 than the less gas-rich DLAs, and may arise in cooler and/or less turbulent gas. Includes observations collected during program ESO 93.A-0422 at the European Southern Observatory (ESO) Very Large Telescope (VLT) with the Ultraviolet-Visual Echelle Spectrograph (UVES) on the 8.2 m telescopes operated at the Paranal Observatory, Chile. Some of the data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation.

  17. Snack Consumption among Iranian Children and Adolescents: The CASPIAN-IV Study

    Maryam BAHREYNIAN

    2015-10-01

    Full Text Available Background: This study aimed to assess the frequency of consuming different types of snacks among Iranian students according to socio-economic status (SES of their living region.Methods: Data were obtained from the fourth national school-based surveillance survey entitled CASPIAN-IV study. Overall, 14880 school students, aged 6-18 years, were selected through multistage, cluster sampling from rural and urban areas of the of 30 provinces of Iran. The World Health Organization Global School Student Health Survey (WHO-GSHS was used. Data were compared at national/sub-national levels by survey data analysis methods.Results: The participation rate was 90.6%, 13486 students (49.2% girls, mean (SD age of 12.50 (3.36 years completed the study. At national level, fresh fruits were the most common used category of healthy snacks (55.74%, 95% CI: 54.51, 56.96. Boys had more daily consumption of milk (48.65% vs. 43.27%, and girls had more daily consumption of fresh fruits (58.07% vs. 53.47%. Urban residents had lower consumption of vegetables (30.53% vs. 37.55%, dried fruits (18.29% vs. 23.02%, and fresh fruits (45.33% vs. 50.09% than their rural counterparts. Among unhealthy snacks, sweets had the highest daily consumption (34.15%, 95% CI: 33.04, 35.28. Boys had higher consumption of sweetened beverages (22.57% vs. 17.6% and fast foods (3.51% vs. 2.17%. At national level, except than salty snacks (16.24% rural vs.11.83% urban, consumption of other junk snacks had no significant difference between urban and rural residents.Conclusion: Differences in the frequency of consuming healthy and unhealthy snacks according to the SES of the living region, and the choice differences between genders should be considered in planning national health programs. Keywords: Snack, Healthy snack, Junk food, Socio-economic status, Iran 

  18. Wind tunel tests of Risoe-B1-18 and Risoe-B1-24

    Fuglsang, P.; Bak, C.; Gaunaa, M.; Antoniou, I.

    2003-01-01

    This report contains 2D measurements of the Risoe-B1-18 and Risoe-B1-24 airfoils. The aerodynamic properties were derived from pressure measurements on the airfoil surface and in the wake. The measurements were conducted in the VELUX open jet wind tunnel, which has a background turbulence intensity of 1%, and an inlet flow velocity of 42 m/s. The airfoil sections had a chord of 0.600 m giving a Reynolds number of 1.6Oe106. The span was 1.9 m and end plates were used to minimize 3D flow effects. The measurements comprised both static and dynamic inflow. Static inflow covered angles of attack from 5o to 30 deg. Dynamic inflow was obtained by pitching the airfoil in a harmonic motion around various mean angles of attack. The test matrix involved smooth flow, various kinds of leading edge roughness, stall strips, vortex generators and Gurney flaps in different combinations. The quality of the measurements was good and the agreement between measurements and numerical CFD predictions with EllipSys2D was good. For both airfoils predictions with turbulent flow captured very well the shapes of lift and drag curves as well as the magnitude of maximum lift. Measurements of Risoe-B1-18 showed that the maximum lift coefficient was 1.64 at an angle of attack of approximately 13 deg. The airfoil was not very sensitive to leading edge roughness despite its high maximum lift. Measurements with stall strips showed that stall strips could control the level of maximum lift. The Risoe-B1-24 measurements showed that the maximum lift coefficient was 1.62 at an angle of attack of approximately 14 deg. The airfoil was only little sensitive to leading edge roughness despite its high relative thickness and high maximum lift. Measurements with delta wing shaped vortex generators increased the maximum lift coefficient to 2.02 and measurements with Gurney flaps increased the maximum lift coefficient to 1.85. Measurements with combination of vortex generators and Gurney flaps showed a maximum increase in the maximum lift coefficient to 2.17. At the design Reynolds number of 6Oe10{sup 6} numerical predictions showed that there was a clear increase in the maximum lift coefficient of 0.22 for Risoe-B1-18 and 0.21 for Risoe-B1-24. (au)

  19. Determination the total neutron yields of several semiconductor compounds using various alpha emitters

    Abdullah, Ramadhan Hayder; Sabr, Barzan Nehmat

    2016-03-01

    In the present work, the cross-sections of (α,n) reactions available in the literature as a function of α-particle energies for light and medium elements have been rearranged for α-particle energies from near threshold up to 10 MeV in steps of (0.050MeV) using the (Excel and Matlab) computer programs. The obtained data were used to calculate the neutron yields (n/106α) using the quick basic-computer program (Simpson Rules). The stopping powers of alpha particle energies from near threshold to 10 MeV for light and medium elements such as (nat.Be,10B,11B,13C,14N,nat.O,nat.F,nat.Mg,nat.Al,29Si,30Si, nat.P and 46.48Ti) have been calculated using the Zeigler formula. The kinetic energies (Tα) and the branching ratios of each α-emitters such as (211Bi, 210Po, 211Po, 215Po, 217At, 218Rn, 219Rn, 222Rn, 224Ra, 226Ra, 215Th, 228Th, 232U, 234U, 236U, 238U, 238Pu, 239Pu, 241Am, 245Es, 252Fm, 254Fm, 256Fm, 257Fm and 257Md) are taken into consideration to calculate the mean kinetic energy . The polynomial expressions were used to fitting the calculated weighted average of neutron yields (n/106α) for natural light and medium elements such as (Be, B, C, N, O, F, Mg, Al, Si, P and Ti) to determine the adopted neutron yields from the best fitting equation with minimum (CHISQ) at mean kinetic energies of various α-emitters. The total neutron yields (n/s/gx/ppmi) of the mentioned natural light and medium elements have been calculated using the adopted neutron yields (n/106α) from the fitting equations at mean kinetic energies of various α-emitters. The total neutron yields (n/s/gα-emitters/gcompounds) of semiconductor compounds such as (AlN, AlP, BN, BP, SiC, TiO2, BeSiN2, MgCN2, MgSiN2 and MgSiP2) have been calculated by mixing (1gram) of compounds with (1gram) of pure α-emitters using the quick basic computer program. The aim of the present work is to constructed and fabricate the neutron sources theoretically

  20. 组配改良剂对重金属污染土壤理化性质及有效养分的影响%Effects of Combined Amendments on Physicochemical Properties and Available Nutrients of Soil Contaminat-ed with Heavy Metals

    邱琼瑶; 周航; 曾卉; 王英杰; 廖柏寒

    2014-01-01

    Chemical fixation is one of remediation techniques for heavy metal contaminated soils. This study was designed to examine and e-valuate the effects of combined amendments(calcium carbonate+sepiolite)on soil pH, organic matter content, available micronutrients in soil, and contents of Pb and Cd in brown rice. Compared to the control, application of combined amendments decreased contents of Pb and Cd in brown rice, and elevated soil pH(from 5.57 to 7.34)and CEC by 217% at 16 g·kg-1 of combined amendments). No significant changes were observed in soil organic matter(range from-2%to 7%). Soil exchangeable Ca and Mg were enhanced by 293%and 22%, re-spectively, after application of combined amendments. Soil available N, P and K did not show significant correlationship with amounts of combined amendments. Soil available Fe reduced in the amendment treatments, but had no relation with application rates. These results in-dicate that application of combined amendments(calcium carbonate+sepiolite)could increase soil pH, improve soil nutrient holding ca-pacity, and decrease heavy metals in brown rice.%采用水稻盆栽实验,对施用组配改良剂(石灰石+海泡石)前后盆栽土壤的酸碱性、有机质含量和营养元素有效态含量,盆栽水稻糙米Pb、Cd含量进行分析和评价。结果显示:施用组配改良剂能够降低水稻糙米Pb、Cd含量,显著提高土壤pH值(从5.57到7.34)和土壤CEC(添加量达到16 g·kg-1时,比对照提高217%);但是施用组配改良剂对土壤有机质含量影响未达显著水平,其变化率在-2%到7%之间。另一方面,施用组配改良剂对土壤中营养元素(Ca、Mg)有效态含量有提高作用,最多比对照分别提高293%和22%;组配改良剂添加量与土壤中碱解N、有效P、速效K含量无显著相关性;施用组配改良剂会降低微量营养元素Fe有效态的含量,但添加量与有效态含量并无显著相关性。因此,本研

  1. Discólisis percutánea con ozono: nuestra experiencia Percutaneous ozone discolysis: our experience

    M. Castro

    2009-10-01

    Full Text Available Objetivo: Demostrar la eficacia y seguridad clínica de la discólisis percutánea con ozono en el tratamiento de la hernia discal lumbar sintomática. Material y métodos: Estudio observacional prospectivo en 41 pacientes diagnosticados de hernia discal lumbar sintomática, a los que se les realizó un total de 49 discólisis percutáneas con ozono durante el período comprendido entre febrero de 2004 y febrero de 2009. Todas las discólisis se realizaron en quirófano, bajo control radioscópico, con medidas de asepsia habitual, anestesia local y sedación. Se administró ozono intradiscal (5 a 7 ml, epidural (5 a 7 ml y perirradicular (5 a 7 ml a una concentración de 27 µg. En todos los casos se administró quimioprofilaxis con 1.500 mg de cefuroxima. La eficacia del tratamiento se basó en el control del dolor según la escala visual analógica basal (EVA 0, a los 30 días (EVA 1, a los 90 días (EVA 3 y a los 6 meses (EVA 6 de las discólisis y mediante el test de Lattinen evaluado antes del tratamiento (TLT 0 y al final del estudio (TLT 1. Todos los pacientes fueron preguntados acerca de posibles efectos secundarios y finalmente se registró el grado de satisfacción. Resultados: Se realizaron 49 discólisis percutáneas con ozono en 41 pacientes. La EVA media inicial fue de 7,37 ± 0,96 y la evolución al mes, a los 3 y a los 6 meses fue: 2,41 ± 2,17, 1,80 ± 2,31 y 2,05 ± 2,45, respectivamente, con diferencia estadísticamente significativa en los 3 cortes. El índice de Lattinen medio inicial fue de 12,68 ± 2,32 y pasó a 6,07 ± 2,91 a los 6 meses, con una reducción también estadísticamente significativa. Solamente 5 pacientes (12,2% presentaron efectos adversos que consistieron en 4 cefaleas transitorias leves y un neumoencéfalo bastante incapacitante que obligó al paciente a guardar reposo en cama durante 1 semana hasta su reabsorción espontánea. En cuanto a la satisfacción expresada por los pacientes fue buena para 35 (85,4%, regular para 4 (9,8%, y solamente 2 (4,9% la calificaron de mala. Conclusiones: La discólisis percutánea con ozono se muestra como una técnica eficaz y segura en el tratamiento del dolor lumbar irradiado secundario a hernia de disco lumbar.Objective: To demonstrate the safety and effectiveness of percutaneous discolysis using ozone in the treatment of symptomatic lumbar hernia. Material and methods: We performed a prospective observational study in 41 patients diagnosed with symptomatic lumbar hernia, in whom we performed 49 percutaneous discolysis procedures introducing ozone in the lumbar region between February 2004 and February 2009. All the procedures were performed in the operating room under radiological guidance, with aseptic conditions, local anaesthesia and sedation. The ozone was introduced into the lumbar disc (5 to 7 ml, in the epidural (5 to 7 ml and periradicular spaces (5 to 7 ml at a concentration of 27 Ìg. In all patients, 1500 mg of cefuroxime was administrated intravenously as a prophylactic measure. The effectiveness of the treatment was based on pain control according to the visual analogue scale before the procedure (VAS 0, at 30 days (VAS 1, at 90 days (VAS 3 and at 6 months (VAS 6, and by means of Lattinen's test before treatment and at the end of the study. All the patients were asked about the possible adverse effects of the treatment and a survey was carried out on patient satisfaction with the technique. Results: We performed 49 percutaneous ozone discolysis procedures in 41 patients. The initial mean VAS was 7.37 ± 0.96 and subsequent values were 2.41 ± 2.17 at 1 month, 1.80 ± 2.31 at 3 months and 2.05 ± 2.45 at 6 months, with statically significant differences in the three measurements. The initial mean Lattingen index was 12.68 ± 2.32 and was 6.07 ± 2.91 at 6 months, representing a statically significant reduction. Adverse effects occurred in only five patients (12.2%: four mild transient headaches and one symptomatic pneumoencephalos, requiring bed rest for 1 week until spontaneous reabsorption. The degree of satisfaction was good in 35 patients (85.4%, acceptable in four (9.8% and bad in only two patients (4.9%. Conclusions: Percutaneous ozone discolysis is a safe and effective technique in the treatment of symptomatic lumbar hernia.

  2. Velocidade de estabelecimento de acessos de amendoim forrageiro na Amazônia Ocidental Speed of establishment of accessions of forage peanut in the Western Amazon

    Judson Ferreira Valentim

    2003-12-01

    Full Text Available O objetivo deste estudo foi avaliar a velocidade de estabelecimento de acessos de amendoim forrageiro (Arachis repens e Arachis pintoi, visando selecionar materiais adaptados aos sistemas intensivos de produção pecuária do Acre. O delineamento experimental utilizado foi de blocos casualizados, com quatro repetições. Os tratamentos consistiram de dois acessos de A. repens, sete acessos e duas cultivares de Arachis pintoi identificados como promissores para as condições ambientais de Rio Branco, Acre. Foi adotado como testemunha A. pintoi cv. Amarillo. Os acessos Ap 65, Ap 39 e Ar 10, com desempenho semelhante às cultivares Amarillo e Belmonte, destacaram-se por apresentar excelente velocidade de estabelecimento, com índice de sobrevivência das mudas e cobertura do solo superiores a 80% e comprimento dos estolões acima de 85 cm, respectivamente, aos 50, 70 e 120 dias após o plantio. Estes genótipos apresentaram produtividade de matéria seca (MS superior a 2.300 kg/ha, taxas de acúmulo de MS iguais ou superiores a 20 kg/ha/dia e teor de proteína bruta variando entre 17,9 e 21,7%, no final do período de estabelecimento. Entre os quatro grupos heteróticos, o formado pelo acesso Ap 39 destacou-se dos demais, por apresentar valores médios a altos para todas as características avaliadas, de acordo com a análise de agrupamento realizada pelo Método de Otimização de Tocher, com base na distância generalizada de Mahalanobis. Para que os materiais promissores possam ser recomendados para uso nos sistemas intensivos de produção de bovinos no Acre, devem ser desenvolvidos estudos adicionais com relação à: 1 produtividade e qualidade de MS nos períodos chuvoso e seco; 2 ocorrência de pragas e doenças; 3 produção de sementes; 4 adaptação a solos de baixa permeabilidade; 5 compatibilidade com gramíneas forrageiras e espécies arbóreas e arbustivas perenes; 6 produção animal e persistência sob pastejo.The objective of this study was to evaluate the speed of establishment of accessions of Arachis repens and Arachis pintoi with the purpose of selecting materials capable of producing adequate quantities of high quality forage, according to the requirements of the intensive cattle production systems of Acre. The experimental design was a randomized block with four replications. The treatments consisted of two accessions of Arachis repen, seven accession and two cultivars of Arachis pintoi, identified as promising for the environmental conditions of Rio Branco, Acre. The control treatment was A. pintoi cv. Amarillo. The accessions Ap 65, Ap 39 and Ar 10, with performance similar to the cultivars Amarillo and Belmonte, were selected because of their excellent speed of establishment with index of survival of stolon and rhizome plantings and ground cover higher than 80% and length of stolons above 85 cm, respectively, 50, 70 and 120 days after planting. These genotypes showed DM yields above 2,300 kg/ha, DM accumulation rates equal or superior to 20 kg/ha/day and crude protein content ranging from 17.9 to 21.7%, at the end of the establishment period. Among the four heterotic groups, the one consisting of accession Ap 39 outranked the others by presenting high mean values for all the characteristics evaluated according to the cluster analysis by the Tocher Optimization Method, based on the generalized Mahalanobis. For the recommendation of the promising accessions for use in the intensive cattle production systems in Acre, additional studies should be conducted in relation to: 1 dry matter yield and quality during the rainy and dry seasons; 2 occurrence of pests and diseases; 3 seed production; 4 adaptation to low permability soils; 5 compatibility with grasses and shrub and tree species; 6 animal production and persistence under grazing.