最新刊期
卷 0 ， 期 0 ， 2020
- 关键词：removal of SO2 and NOx;acid rain;flue grases
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发布时间：2022-09-13 - 摘要：A set of geological samples of Cretaceous—Tertiary section taken from Zhongba county, Tibet, was studied with neutron activation technique. The preliminary experimental results reveal that the high concentration of iridium exists in the clay layer at the C-T boundary. On the basis of the anomaly of Ir, variation of CaCO3 contents and REE abundance patterns, possible mechanisms were examined, among which the impact of extraterrestrial substance on the earth is very attractive.关键词：Neutron activation;rare event;iridium anomaly
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发布时间：2022-09-13 - 摘要：This paper describes the basic principle and experimental arrangement of accelerator mass spectrometer based on 2.5 MV Van de Graaff accelerator, and the concentrations of tritium in the heavy water samples have been determined. For comparision the measurement was also carried out with radioactive method. The experimental result has demonstrated that tritium at concentration of 1 part in 1014 can be determined with a 1—2 MeV Van de Graaff accelerator mass spectrometer, and the potential sensitivity would be 2—3 orders higher. The prospect and problem on this small accelerator mass spectrometer have also been discussed.关键词：Van de Graaff accelerator mass spectrometry;radioactive method;method of direct counting of atoms;Heavy water;Tritium
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发布时间：2022-09-13 - 摘要：Under some conditions, there is a simple hyperbola function relationship between the ratio of the characteristic X-ray intensity of an element analysed to Compton scattering intensity by primary X-ray and the ratio of the characteristic X-ray intensity of the element to the intensity measured with a absorbent filter. The hyperbola function relationship enables us to improve the matrix effect easily by using the method of "characteristic/scattering ratio" with a portable radioisotope X-ray fluorescence single channel analyzer. The results of this new method is fairly identical with that of "characteristic/scattering ratio". Besides, there is no need of extra devices and it saves time and money. Many types of Sn samples and one type of Cu sample have been analysed.关键词：portable RI X-ray fluorescence analyzer;Matrix effect;tin ore samples;the ratio of characteristic to scattering;the ratio of characteristic to absorbent hyperbola function fitting
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发布时间：2022-09-13 - 摘要：The application characteristics, construction and operation principles of the curved crystal spectrometer of MWPC are described in this paper. The construction and the values of characteristics for MWPC are reported as well. Finally, the objective to separate Kα1 and Kα2 is achieved in measuring the Kα characteristic line of iron with the instrument.关键词：MWPC;curved crystal spectrometer
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发布时间：2022-09-13 - 摘要：The cubic spline has been used as the efficiency curve model of Ge (Li) gamma-ray spectrometric instrument and improved the algorithm of stepwise regression. Methods such as AIC test etc have also been employed to majorize the model. Thus the problems of the numbers of the partition points, the locations of the best points and the continuity of fitting function at these points are solved. This model contains fewer parameters and better precision than those old ones.We have used this method to do efficiency calibration for our 185 cm3 Ge (Li) coaxial detector. The every model obtained contains only three parameters and the precision is about 2.5% in the region from 59 keV to 1408 keV. The deviation of 152Eu emissionrate measured by our calibrated system from the international comparision at 1978 is equal to or less than 3%.关键词：fitting a curve;Efficiency calibration;γ-spectrum;spline;stepwise;regression minimum information theoretic criterion
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发布时间：2022-09-13 - 摘要：This Mobley type magnet is installed on the 2.5MV Van de Graaff machine in our institute. It is a main facility for obtaining about 1 ns pulsed beam. The 10—15 ns pulsed beam can be compressed into 0.9—1.1 ns and 1.3—1.5 ns for H+and D+, respectively. The observed optimum beam spot size is about 3×4 mm2 at the target. The energy both for H+ and D+ ions rangs from 1.5 to 2.3 MeV with the energy resolution about±0.5%.关键词：broad window magnet;Van de Graaff accelerator
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发布时间：2022-09-13 - 摘要：The content of ash in peat is determined by using the X-ray backscattering method. The radioactive source used is 238Pu. The average standard error is about 3% compared with those of chemical methods, and the causes of the error are discussed.关键词：X-ray backscattering;peat;photoelectric effect;spectrum;bulk density
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发布时间：2022-09-13 - 摘要：The construction and operation of a parallel plate avalanche counter for heavy ion detection is described. The time resolution of 250 ps (FWHM) for the whole time-of-flight system has been measured with 93 MeV nitrogen ions.关键词：parallel plate avalanche counter;time-of-flight measurement
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发布时间：2022-09-13 - 摘要：The 25 MeV betatron in Qinghua University has been used for nondestructive testing on 40 petroleum diamond drill bits, among them 6 have been found with defects like crackles. The detecting sensitivity could reach 1%.关键词：betatron;nondestructive testing
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发布时间：2022-09-13 - 摘要：Using delayed-coincidence measurement between 123 keV and 14.4 keV gamma rays from 57Fe, we have studied the time dependence of gamma rays. The 123 keV gamma ray signals the formation of the 14.4 keV Mössbauer level. When no filter is used, the number of gamma rays decrease exponentially with the known half-life of 0.1 ns; when a foil containing 57Fe (which is resonant to 14.4 keV radiation) is used as a filter, the number of gamma rays do not decrease exponentially. The detail of the measured decay curve depends on the thickness of the absorber and the energy shifts between the source and filter. We measured the time spectra with energy shifts of ω=0 and Δω=2.5Γ. The theoretical curve are also calculated to fit the experimental data. For comparison, the regular Mössbauer spectra and the coincidence-Mössbauer spectra are measured.关键词：Mossbauer spectra;filtered resonance radiation;delayed-coincidence measurement;natural line width;time dependence
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发布时间：2022-09-13 - 摘要：Because of the poor focusing performance of the beam from our 1.2 m cyclotron, the background gamma ray and neutron are very high in the target hall. Particularly, the high intensity neutron will damage the Ge (Li) detector. A proper shield assembly is used to decrease the interference of such background and the level of background neutron is reduced to 2—3 neutrons/cm2•s. On this condition the in beam γ-ray spectra of 199Tl from the 197Au (α, 2nγ) reaction have been measured.关键词：in beam γ-ray spectroscopy;199T1;irradiation
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发布时间：2022-09-13 - 摘要：This paper describes the preparation and animal tests of 99mTc-labelled urokinase thromboemboli imaging agent. This agent can be localized in thrombus after injection and visualized by Gamma camera or scintillation scanner. There is no allergic reaction from non antigen reaction.99mTc-urokinase can be used not only in diagnosis of deep vein thrombosis, but also in locating thrombus in transplant organs.关键词：technetium-99m labelled urokinase;Thrombosis;embolism
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发布时间：2022-09-13 - 摘要：This paper describes the distribution of I123 labelled OIH in animal by animal renal autoradiography and clinical application.The renogram gives three distinct phases: tracer appearance, buildup and excretion.The renograms of 123I-OIH and 131I-OIH are similar in pattern.关键词：renogram;123iodine-orthoiodohippurate (123I-OIH);kidney
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发布时间：2022-09-13 - 摘要：The preliminary results obtained have shown that radiation can make wine better in quality and taste sweet and mellow. Through chromatographic analysis it was shown that the irradiated Baishaye wine has higher contents of total ester, total alcohol, total aldehyde and total acid than the control. Except for iso-butanol, eghyl valerate and hexanoic acid, the ethyl caproate ethyl lactate, ethyl acetate, ethyl formate, ethyl butyrate, n-propyl alcohol, secondary butanol, n-butanol, isoamyl alcohol, acetaldehyde, acetal, biacetyl, formic acid, acetic acid and latic acid in the irradiated wine are all higher than those of control.关键词：Baishaye wine;Irradiation;chromatographic analysis
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发布时间：2022-09-13 - 摘要：Four (125I) iodinated peptide tracers, (125I) growth hormone, (125I) alpha fetoprotein, (125I) porcine proinsulin and A14- or A19-(125I) monoiodoinsulin labelled with domestic-made Na125I by lactoperoxidase or chloroamine T method were purified successfully by polyacrylamide gel electrophoresis. The tracers were characterized in radioimmunoassay systems in terms of their immunoreactivity, specific radioactivity and stability during storage.The results show that both LPO and ChT could be used as oxidizing agent except LPO for alpha fetoprotein. There were no marked differences concerning the immunoreactivity of tracers labelled by LPO or ChT judging from dose-response curve. The specific radioactivity for (125I) hGH, (125I) aFP, (125I) porcine proinsulin, A14- and A19-(125I) monoiodoinsulin were 110, 33, 145, 100—250 and 80—160 mCi/mg respectively determined by self-displacement method. The shelf-time of these four tracers were about 2—3, 1.5—2, 1.5 and 3—5 months respectively.It is shown that polyacrylamide gel electrophoresis is an effective method for purification of (125I)-iodinated peptide tracers.关键词：human growth hormone;Porcine proinsulin;alpha fetoprotein;polyacrylamide gel electrophoresis;immunoreactivity;radioimmunoassay;specific radioactivity;peak radioactivity recovery;excess antibody binding;iodination yield
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发布时间：2022-09-13 - 摘要：In this paper separation of 57Co-Ni, Cu by ion-exchange method is described. In 9N HCl nickel passes easily through the column, leaving Co and Cu in the column, 57Co is eluted by 4N HCl with copper remaining on the column.关键词：57Co;ion exchange separation
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发布时间：2022-09-13 - 摘要：An irradiation facility of 137Cs gamma source, has been established in 1981 in Hangchow and functioned normally since then. The intensity of 137Cs gamma source used is 50 kCi. The source is composed of a cast cylinder of 137Cs chloride, doubly encapsulated in high integrity stainless steel casting filled with helium and sealed by welding. The dimensions of the cylinder were 52 mm in outer diameter and 480 mm in length, having characteristics of a single line source. The pool is 5 m in depth under the floor locating at the center of the cave. The source is arranged on the elevator frame. The top end of the source was kepted 3 m under water level, so that it can meet the need of safty requirement of 2.68 m under the water level. The irradiation cave was shielded with concrets wall of 1.56 m for the sake of residents safety nearby. The roof of the cave was designed in arched form.This pool type designs, in comparing with dry-well type is more simple, safe, and-easy to operate and repair etc.关键词：cesium-137;irradiation cave;irradiation shielding;pool
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发布时间：2022-09-13 - 摘要：This paper describes synthesis of 2-14C-Alloxan from 14C-urea condensation with malonic ester to form barbituric acid, and directly oxidization of it by chromium oxide. The yield of two steps was 50%. The chemical and radiochemical purities of Alloxan assessed by paper chromatography were over than 95%. The specific activity of barbituric acid was 2.84 mCi/mmol and that of Alloxan was 2.46 mCi/mmol.关键词：alloxan;carbon-14;Labelled compound
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发布时间：2022-09-13 - 摘要：The I-123 obtained from 121Sb (α, 2n) 123I reaction and separated by dry distillation in this institute gave a thyroid uptake of 45 D %/g in distribution test. The ratio of thyroid uptake to that of other organs were 10—45 and has a maximum appeared in 1—6 after injection. Clear thyroid imagi ngs were obtained by both rectillinear scanner and gamma camera in 1—6 h after iv to rabbits.关键词：I-123;in-vivo distribution;uptake thyroid imaging;mice;rabbit
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发布时间：2022-09-13 - 关键词：ichthyology;tracer techniques;nutrition physiology;reproductive endocrinology;ecology;radioimmuoassay
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发布时间：2022-09-13
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