共查询到20条相似文献,搜索用时 15 毫秒
1.
Levels of 184Os populated in the decay of 3.1 h 184Ir and in the 185Re(p, 2nγ) reaction have been investigated. The measurements included γ-ray singles, β+ ray endpoint, conversion coefficient, β+-γ coincidence and detailed γ-γ coincidence determinations. The results have established an extensive 184Os level scheme, which includes well developed ground state, γ-vibrational and K = 3 octupole bands and which accommodates all the intense transitions observed in both the radioactivity and in-beam γ-ray measurements. Deviations of the level energies in the Kπ = 0+and Kπ = 2+ bands and of the interband reduced transition probabilities from the predictions of the strong-coupling model are discussed in terms of the rotationvibration interaction, and the systematics of the octupole vibrational excitations in even-mass W and Os nuclei are reviewed. It is concluded that the 184Ir ground state configuration has a spin of 5, and that it contains large admixtures of K = 0 or K = 1 character. 相似文献
2.
L. Głowacka M. Jaskóła J. Turkiewicz L. Zemlo M. Kozłowski W. Osakiewicz 《Nuclear Physics A》1975,244(1):117-124
The energy spectra of α-particles emitted in the reactions have been measured at a neutron energy of 18.15 MeV. For the reaction the α-particle angular distribution has been measured as well. The results have been analysed in terms of statistical, pre-equilibrium and knock-on models. 相似文献
3.
Measurements were performed of the ratio of ternary to binary fission (T/B) in 239Pu by neutrons in the energy region from 0.020 eV to 50 eV. The ternary and binary fission time-of-flight spectra were recorded at a 8.1 m flightpath at the Geel Linac with large gold-silicon surface-barrier detectors on both sides of a 1 mg/cm2 double-faced 239Pu target. From these time-of-flight spectra the ratios of the areas of the strongest isolated resonances in ternary and in binary fission were calculated; moreover in the region 0.02–1 eV ratios were calculated for about 40 zones throughout the spectrum. The T/B ratio does not vary significantly in the energy region below 1 eV; this is not the case in the region 1–50 eV, where the T/B value for the 15.5 eV resonance is significantly larger than for the other resonances. These T/B values seem to be correlated with the resonance spin J and with some other fission characteristics. 相似文献
4.
E. Barth I. Tugtekin H. Weidenbach U. Wachter J. Vogt P. Radermacher 《Isotopes in environmental and health studies》2013,49(1-2):209-213
Abstract Breath tests using 13C-labelled substrates require the measurement of 13CO2/12CO2 ratio in breath gas samples. Next to isotope ratio mass spectrometry (IRMS), which is very sensitive but also complex and expensive, alternatively isotope selective nondispersive infrared spectrometry (NDIRS) can be used to determine the 13CO2/12CO2 ratio in expired breath. In this study we compared NDIRS- with IRMS-results to investigate whether the less expensive and very simply to operate NDIRS works as reliable as IRMS. For this purpose we applicated 1-13C-Phenylalanine to patients with advanced liver cirrhosis and healthy volunteers and took duplicated breath samples for IRMS and NDIRS at selected time points. Our data show a good correlation between these two methods for a small number of samples as required for simple breath tests. Longer series, where repeated measurements are required on the NDIRS instrument lead to a decreasing correlation. This indicates the superiority of IRMS concerning 13CO2-kinetics over longer time periods. 相似文献
5.
Fission of 232Th, 237Np, 209Bi, 235U and 238U induced by 110 MeV electrons has been studied by means of surface barrier detectors. The resulting mass and kinetic energy distributions are presented. Comparison with the liquid drop model predictions shows reasonable agreement in the case of 209Bi. The data are analysed in terms of a two component model of fission and the mean total kinetic energies of the components are shown to depend linearly on . Interesting differences are found when the present results are compared with the recent photofission experiments of Areskoug et al. and features in both sets of data correlate with changes of fragment deformation implied by the calculations of Wilkins et al. 相似文献
6.
A Coulomb excitation experiment has been performed on the first 2+ states of 122Te, 124Te and 130Te. The relative excitation probabilities of the first 2+ states were measured at backward and forward projectile scattering angles. Particle-γ coincidences were used to identify the inelastic events. The data were analyzed with the aid of the Winther-deBoer multiple Coulomb excitation program. Separate γ-ray angular distribution measurements were made as a function of target recoil velocity to determine the influence of the deorientation effect. The projectile and bombarding energy were chosen to minimize the effect on the experiment of higher state interference due to Coulomb excitation of the first 2+ state via the second 2+ state. For positive higher state interference the extracted quadrupole moments of the first 2+ states are Q2+ = ?0.43 ± 0.08 b, ?0.49 ± 0.08 b and ?0.08 ± 0.08 b for 122Te, 124Te and 130Te respectively. These results and other measurements of Q2+ for the doubly even Te isotopes are used to discuss the model dependent calculations of Q2+. 相似文献
7.
The activity concentrations of the natural radionuclides namely 238Ra, 232Th and 40K are measured for soil samples collected from different locations of Faridkot and Mansa districts of Punjab. HPGe detector,
based on high-resolution gamma spectrometry system is used for the measurement of activity concentration. The range of activity
concentrations of 226Ra, 232Th and 40K in the soil from the studied areas varies from 21.42 Bq kg−1 to 40.23 Bq kg−1, 61.01 Bq kg−1 to 142.34 Bq kg−1 and 227.11 Bq kg−1 to 357.13 Bq kg−1 with overall mean values of 27.17 Bq kg−1, 95.22 Bq kg−1 and 312.76 Bq kg−1, respectively. Radium equivalent activities are calculated for the analyzed samples to assess the radiation hazards arising
due to the use of these soil samples in the construction of dwellings. The absorbed dose rate calculated from activity concentration
of 226Ra, 232Th and 40K ranges between 9.87 and 18.55, 38.01 and 88.68 and 9.40 and 14.79 nGy h−1, respectively. The total absorbed dose in the study area ranges from 61.10 nGy h−1 to 112.86 nGy h−1 with an average value of 84.80 nGy h−1. The calculated values of external hazard index (H
ex) for the soil samples of the study area range from 0.36 to 0.68. Since these values are lower than unity, according to the
Radiation Protection 112 (European Commission, 1999) report, soil from these regions is safe and can be used as construction
material without posing any significant radiological threat to population. The corresponding average annual effective dose
for indoor and outdoor measured in the study area are 0.42 mSv and 0.10 mSv respectively.
相似文献
8.
E. Therssen Y. Bouvier C. Schoemaecker-Moreau X. Mercier P. Desgroux M. Ziskind C. Focsa 《Applied physics. B, Lasers and optics》2007,89(2-3):417-427
A new method is proposed to measure the ratio of the refractive index function of soot particles E(m) at the two fixed wavelengths:
532 and 1064 nm. Using a non-intrusive, in-situ laser based technique, the ratio E(m,1064 nm)/E(m,532 nm) can be determined
by comparing laser induced incandescence (LII) intensities at 532 and 1064 nm excitation wavelengths. The method consists
of selecting laser energies that insure the equality of the LII signals in the low fluence regime under given conditions.
Such equality is consistent with the fact that the soot particle will have reached the same temperature independently of the
laser wavelength, i.e. the soot particle has absorbed the same energy. As the absorbed energy is proportional to the laser
irradiance times E(m), the measurement of the laser energies required to insure perfect concordance of the LII intensities
(spatially and temporally) serves to deduce the ratio E(m,1064 nm)/E(m,532 nm). The method is demonstrated in an acetylene/air
flame, validated against extinction measurements performed by cavity ring-down spectroscopy (CRDS) by using laser radiations
at 532 nm and 1064 nm and finally applied to different flame conditions.
PACS 78.20.Ci; 78.90.+t; 81.05.Uw; 42.62.-b 相似文献
9.
环境中天然伽马射线主要来源于40K以及钍系、铀系和锕系.通过探测伽马射线来识别放射性核素并得到它们的相对含量,是核科学与核技术中的一个重要方法.利用高分辨的高纯锗探测器,北航以及国内部分高校已开设了鉴别环境中放射性核素的实验.在此基础上,本文进一步利用特征γ射线与递次衰变规律,对北航沙河校区土壤中的40 K、238 U... 相似文献
10.
基于~(85)Rb原子5S1/2-5P3/2-5D_(5/2)阶梯型能级系统(780 nm+776 nm),利用高信噪比的电磁诱导透明谱对~(85)Rb原子5D_(5/2)态超精细分裂进行测量.其中,频率校准是通过位相型电光调制器和共焦法布里-珀罗腔共同实现的.通过测量~(85)Rb原子5D′5/2态(F′=5),(F′′=4)及(F′′=3)之间的超精细分裂,我们确定了~(85)Rb原子5D_(5/2)态的磁偶极超精细相互作用常数(A=-(2.222±0.019)MHz)和电四极超精细相互作用常数(B=(2.664±0.130)MHz). 相似文献
11.
By continuing the 2H(, p)3H, Ed = 13.0 MeV tensor polarizations to the forward and backward transfer poles it was possible to determine the corresponding values for the deuteron (0.0268 ± 0.0007) and triton (0.048 ± 0.007). 相似文献
12.
Igor F. Mikhailov Alexey A. Baturin Anton I. Mikhailov Svetlana S. Borisova 《X射线光谱测定》2020,49(5):554-559
A generalization of the Compton method for determining elements with a low atomic number Z from 1 (H) to 9 (F) by the ratio of the intensities of incoherent (Compton) and coherent (Rayleigh) scattering is proposed. The generalization takes into account not only the dependence of this ratio on the effective atomic number of the scatterer material but also the momentum transfer variable x = . The new method is based on the application of calibration function of obtained by measuring scattering spectra at two values of x1= 0.831 Å−1 and x2= 1.297 Å−1 with a WDXRF spectrometer. The elemental atomic numbers and their concentrations of binary compounds with unknown compositions are determined by the solution of a system of linear equations. Coefficients of the equations are calculated from the measured ratios for the test sample and the regularization solution for the corresponding calibration. The experiments have been carried out for standard samples of single-component, binary and triple stoichiometric compounds based on H, Li, Be, B, C, O and F. The identification of these elements was found to be possible in the absence of a relationship between the positions of scattering peaks and the composition of the sample, and a qualitative and quantitative analysis of the composition of the material was carried out as part of the solution of a single inverse problem. 相似文献
13.
Keita Yamada Ryota Hattori Yuji Ito Hiroki Shibata Naohiro Yoshida 《Isotopes in environmental and health studies》2013,49(3):392-399
Isotopic signatures of atmospheric methanol and acetaldehyde have the potential to improve our ability to quantitatively assess their importance in atmospheric chemistry. However, isotopic measurements of atmospheric methanol and acetaldehyde and their individual source and sink processes have been limited. In this study, we examined gas chromatography-isotope ratio mass spectrometry combined with headspace solid-phase microextraction to measure the carbon isotope ratios of methanol and acetaldehyde in air samples. The method enabled us to determine carbon isotope ratios with a precision (1 standard deviation) of±0.6 ‰ for 20 ml of air sample containing more than 3 ppm of methanol and±0.7 ‰ for 20 ml of air sample containing more than 2 ppm of acetaldehyde. Moreover, the applicability of this method to determine isotope ratios of methanol and acetaldehyde emitted from detached plant leaves was demonstrated. 相似文献
14.
O. P. Somani T. S. Sunil Kumar B. M. Kukreti B. K. Bhaumik R. A. Gorikhan 《Indian Journal of Physics》2009,83(6):879-885
Gross gamma radiation survey was carried out using Nal(Tl) scintillator based portable gamma ray spectrometer (PGRS) around
areas of Gaonri, Dholera, Pachnota and Meghot in Mahendragarh district, Haryana. Geologically the area forms part of north
Delhi fold belt comprising calc-silicate, quartz biotite schist, impure marble, quartzite and pegmatite rocks. Equivalent
uranium (eU3O8) concentration in ppm was estimated in situ on a regular grid pattern of 500 m (E-W) × 1000 m (N-S) and grab samples were
collected at grid locations for analyzing in the laboratory for estimating the contents of eU3Os Raeq, ThO2 and %K. A comparison with the laboratory analysed grab samples for eU308 data and in situ radiation measurements shows a good match of the two sets of data. The in situ measurements indicate higher
concentration of eU3O8 in Chapra Bibipur in northeastern most corners, Maghot area in central part, Gaonri in western part and Pachnota in southwestern
part of the study area.
As index to uranium favorability, U(Raeq)-Th contour map (prepared using Surfer software with Krieging interpolation method for this grid size) based on the data
on grab samples was generated which show three major clusters of relatively high U-Th ratio. The blocks delineated are enriched
in sodic mineral albite which support albite hosted uranium mineralization potential in metamorphic rocks in Haryana.
相似文献
15.
Determination of the Li/Nb ratio in lithium niobate by means of birefringence and Raman measurements
U. Schlarb S. Klauer M. Wesselmann K. Betzler M. Wöhlecke 《Applied Physics A: Materials Science & Processing》1993,56(4):311-315
Two optical methods for the determination of the Li/Nb ratio in lithium niobate (LiNbO3) are discussed. Data for the optical birefringence method are presented, they cover the entire composition range in which LiNbO3 can be fabricated and a wide spectral region. The line-widths of lattice modes have been measured by means of Raman scattering as a function of the Li/Nb ratio for single crystals with polished and rough surfaces. 相似文献
16.
17.
Z.A. Rostami S.E. Mousavi Ghahfarokhi I. Kazeminezhad 《Chinese Journal of Physics (Taipei)》2018,56(2):760-769
In this paper, lead hexaferrite (PbFe12O19) nanoparticles were synthesized by sol-gel method. In order to prepare PbFe12O19 nanoparticles, the metal nitrates with Fe/Pb?=?8, 10, 11, 12, 14 ratios and citric acid were used. The structure, morphology, magnetic, and dielectric properties of PbFe12O19 nanoparticles were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), vibrating sample magnetometer (VSM) and LCR meter. XRD results revealed that the samples with Fe/Pb?≤?10 and Fe/Pb?>?10 have single-phase hexaferrite and hematite (α- Fe2O3) structures, respectively. As a result, the sample with Fe/Pb?=?10 is single-phase and shows the highest values of the saturation magnetization and remanence magnetization. We found that the values of dielectric constant (ε′) and dielectric loss (ε″) increase with an increase in the Fe/Pb molar ratio from 8 to 12 and then decreases with an increase of Fe/Pb molar ratio to 14. The variation of ac conductivity (σac) with frequency ranging from 1?kHz to 200?kHz showed that electrical conductivity in these ferrites is mainly due to the electron hopping mechanism. 相似文献
18.
L. Joly V. Zéninari D. Courtois 《Journal of Quantitative Spectroscopy & Radiative Transfer》2006,102(2):129-138
A quantum cascade spectrometer was used in the laboratory to study H216O, H218O and HDO line intensities near 6.7 μm. The spectral region ranging from 1483 to 1487 cm−1, which is suitable for the in situ laser sensing of these isotopologues in the atmosphere, was investigated using a continuous-wave distributed feed-back quantum cascade laser. Eight lines of water vapor isopologues were studied—one line of the ν2 band of H216O, one line of the 2ν2-ν2 band of H216O, two lines of the ν2 band of H218O and four lines of the ν2 band of HDO were carefully revisited. The measured intensities were thoroughly compared to relevant molecular databases and other experimental and calculated results. We also observe that the H2O, D2O, HDO equilibrium constant agrees excellently with previously determined values. 相似文献
19.
ICP法测定超临界水氧化设备腐蚀液中铜、铬、铝、镍、钛 总被引:1,自引:1,他引:0
采用光谱法研究了超临界水氧化设备腐蚀液中Cu,Cr,Al,Ni和Ti元素的含量,分析判断不锈钢设备腐蚀状况及其因素。结果表明,超临界设备不锈钢材料主要成分元素Cr在超临界水中有不同程度的溶解,并且溶解程度随温度和压力升高而增大。 相似文献
20.
Molecular dynamics method was employed to study the binding energies and mechanical properties of the selected crystal planes of the energetic/nonenergetic 1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane (HMX)/2-picoline-N-oxide cocrystal in different molecular ratios. The solvent effect in HMX:2-picoline-N-oxide (1:1) was calculated, and the cooperativity effect was discussed in HMX···HF/CH4···2-picoline-N-oxide by using the M06-2X and MP2(full) methods at the 6-311++G** basis set. The density, oxygen balance and detonation velocity were calculated. The results indicate that HMX/2-picoline-N-oxide prefers cocrystalising in the 1:1, 2:1 and 3:1 molar ratios, in which the cocrystals own the highest binding energy and best ductility. The cooperativity effect is present in the cyclic complex with CH4, while the anti-cooperativity effect is found in the HF complex. Thus, in order to obtain stable HMX/2-picoline-N-oxide cocrystal, the solvent with low dielectric constant should be chosen, as is in accordance with the result from solvent effect. The reduced density gradient (RDG) and surface electrostatic potential analysis confirms the cooperativity effect and reveals the nature of decreased sensitivity in complex (or cocrystal). The cocrystals in the molar ratios of 5:1–10:1 could be satisfactory in view of explosive properties. 相似文献