最新刊期
卷 0 ， 期 0 ， 2020
- 关键词：glass scintillator;activator;Li-glass;absolute scintillation efficiency
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发布时间：2022-09-13 - 关键词：radiolytic hydrolysis of cellulose;acidic hydrolysis;enzymatic hydrolysis;glucose lignin;pretreatment
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发布时间：2022-09-13 - 关键词：241Am thin source;α-γcoincidence method;2π ionization chamber of boom nets
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发布时间：2022-09-13 - 摘要：Forty-five tree rings (1881-1925) were taken from a white spruce grown near Campell River in Mackenzie Delta, Canada, for the measurement of 14C activity variation. The 14C content in these specimens was measured with a liquid scintillation counter. The data shows there is a 10‰ variation in 14C contents. which is correlated with sunspot numbers. The physical implication is discussed.关键词：atmospheric 14C fluctuation;11 year solar cycle
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发布时间：2022-09-13 - 摘要：On the basis of more precise experimental law of beta absorption, the calculation formula for plating thickness measurement by beta backscattering is deduced theoretically in this paper, the validity and universality of this formula are verified experimentally.In addition, according to the analysis of experimental data and the parameters of the formula, the measuring range of common used beta isotopes is given and the principle of base correction technique has also been introduced.关键词：plaing thickness measurement;beta backscattering
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发布时间：2022-09-13 - 摘要：In this paper, a dual parameter spectrum data acquisition and processing system based on a microcomputer is described. The main advantage of this system are low cost, convenience to use and the intense stereoscopic sense perception in the displayed spectrum. The data acquisition passage and tne three dimentional spectrum display are described in detail. An example is given.关键词：dual parameter;nuclear spectrum;Data acquisition;Data processing;three dimention display
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发布时间：2022-09-13 - 摘要：The ability of on-line data processing for Model-YSJ LSC is similar to that of commercially available products in tne world market after connecting a MIC-80 microcomputer to the LSC.28 programms are mainly for quench correction and counting error calculation of single or double samples, for RIA, for approximate measurement of chemiluminescence and scatchard plotting, etc.Besides, one can reject experimental 'bad points' on the screen by manipulating the keyboard.The whole programm is written in level II basic and assembly languages, which makes it easy for different users to put in their own programms.关键词：liquid scintillation counter;microcomputer;on-line data processing;Control;Interface
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发布时间：2022-09-13 - 摘要：A device for automatic counting and data reduction is introduced. This device consists of a semiconductor detector, a charge sensitive amplifier, a pulse shaping circuit and a microcomputer. It was successfully used to automatically determine the concentrations of radon and thoron daughters in air.关键词：microcomputer;automatic counting;radon and thoron concentration calculation
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发布时间：2022-09-13 - 摘要：The 1.2 metre cyclotron of Shanghai Institute of Nuclear Research has been used as a high energy mass spectrometer for measurment of 3H content in water sample collected from Mount Yuquan in the suburbs of Beijing.The 3H content was obtained by comparison with a sample containing known 3H concentration. These two samples were concentrated electrolytically by a factor of several hundred. A blank sample containing no 3H was used to subtract the triton background due to the cyclotron interior contamination.Three samples were alternatively introduced into the ion source in the form of gas. The 3H ions were identified and counted by a silicon detector telescope with a 100µm Al foil inserted between the dE/dX and E detector. The cyclotron output was monitored by integrating the 3He counts in the dE/dX detector during the collection of 3H events in the E detector.Our experimental results is in good agreement with the value obtained by beta-decay measurement done at Atomic Energy Institute in Beijing.关键词：accelerator mass spectrometry;tritium unit
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发布时间：2022-09-13 - 摘要：A type of low energy gamma-ray scattering well logger for coal fields is introduced in this paper. It is named the selective gamma-gamma well logger. This divice using an 241Am source is more sensitive to the value of the equivalent atomic number Zeq and valuable in estimation of the ash content in coal.关键词：selective gamma-gamma well logger;coal fields
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发布时间：2022-09-13 - 摘要：An experimental determination of Mössbauer parameters of F-series nitrogen fixation model compounds has been carried out with total errors less than±1%. It has been found that the molecualr formula of this compound is (Et4N) 2[MoxFe4-xS4 (SR) 4]. From the Mössbauer spectrum it can be seen that the isomer shift and quadrupolar splitting values are linear functions of X, which indicates the isomorphous substitution of Mo and Fe. It is deduced from our experimental results that the F-series nitrogenn fixation model compounds synthesized is a mono cubane-like configuration.关键词：F-series nitrogen fixation model compounds;Mössbauer spectru
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发布时间：2022-09-13 - 摘要：Using the relaxation method, a numerical calculation of three dimensional electric field in the central region was described of a three-sector cyclotron with 20° rotation of ion source surface with repect to dee gap.关键词：central region of isochronous cyclotron;relaxation method;numerical calculation of three dimensional electric field
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发布时间：2022-09-13 - 关键词：β scintillation probe of low energy;Plastic scintillator
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发布时间：2022-09-13 - 摘要：3H NMR determination of the assignment and relative intensity of tritium in cortisol and other eight tritiated compounds using JEOL FX-100 NMR spectrometer is described. Only small amounts of radioactivity (about 10~30 mCi) are needed to obtain satisfactory spectrum in determining the position and extent of the tritium labelling.关键词：tritium NMR;tritium-labelling;mannose;galactose;Phenylalanine;Thymine;thymidine;cholesterol;progesterone;cortisol
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发布时间：2022-09-13 - 摘要：Method for determination of N2 fixed by legume crops is reported. By difference method and 15N-A value method the amount of total N2 fixed and percentages of total N2 fixed by 5 soybeans and 2 species of legume grasses are highly corrected (r=0.96, y=1.051x+0.037 for the amount of N2 fixation and r=0.39, y=0.245x+43.597 for the percentage of N2 fixation). It is shown that the estimated percentage of N2 fixed by AN-value method is more reliable than by difference method as a result of comparing the variation coefficents of total amount of N with the variation coefficents of 15N% atom excess for non-fixing N2 crops. It is found that the AN-value method has more advantageous than the difference method and the acetylene-ethylene method for measurement of dinitrogen fixation.关键词：biological N2 fixation;AN-value;nodulating;non-nodulating;N2 fixing crop;N2
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发布时间：2022-09-13 - 摘要：This paper describes the mechanism and detective system of lyoluminesent and discriminated two different life-span kinds of free-radical luminescent factors with the sucrose free-radical decay law.Through experiments it shows that the detective system was in accord with the demands for detecting lyoluminesence.关键词：lyoluminescence;sucrose;detective system;discrimination free-radical
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发布时间：2022-09-13 - 摘要：A procedure of decontaminating emulsified toluene triton-x-100 liquid scintillation cocktail is described. After a single extraction more than 93% tritium activity was decontaminated.关键词：Extraction;Decontamination;liquid scintillator recovery
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发布时间：2022-09-13 - 摘要：In order to increase the figure of merit, the sample chamber was improved and various sample vials were designed.Three kinds of "clean" and high reflexible materials (pure aluminium, teflon and plastic film vaccum-evaporated aluminium) were used as the inner linings of the sample chamber and compared each other.The brass chamber with the teflon inner lining was chosen in our experiment.The diameter of the vials is the same as the usual vials but their height is different. For small sample, if we use a low vial and add appropriate chamber appendages or raise the elevater, the figure of merit can be increased.The homogeneity and the leakage of vials were discussed.关键词：low-level liquid scintillation measurement;sample chamber;sample vial
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发布时间：2022-09-13 - 摘要：In presenta paper, the interference between Sm and U in non-destructive neutron activation analysis has been studied. When the radioactivities of 153Sm and 239Np are close to each other, the 103.2keV photopeak of 153Sm and the 103.7keV photopeak of 239Np (239Pu) do not appear correctly if the single-peak analysis is used. It seriously interfered the accurate measurement of Sm. The overlapping-peak-analysis program designed by our laboratory can be used to obtain the mixture of these two peaks. We use the stripping method. i. e. after stripping the spectrum of pure uranium, the mixed γ spectrum of Sm and U go through the single-peak or overlapping-peak analysis. By this way, we can get the pure 103.2keV photopeak of 153Sm quite accurately. The stripping method can be used to strip the contributions of all the fission products of uranium. This also is the one of its advantages. The stripping method may have other applications in non-destructive neutron activation analysis.关键词：non-destructive neutron activation analysis;interference;stripping method
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发布时间：2022-09-13 - 摘要：The radio-paper chromatograph scanning instrument may be used for the measurment of radionuclides emitting low energy β and γ rays with the background being about 30 cpm. Its efficiency was 1~3% (3H), 20~26% (14C) and 8~10% (125I). The scanning sensitivity was 0.01µCi (3H), 0.001µCi (14C) and 0.004µCi (125I). Its localization resolving power was about 5mm and a comparison was made with the liquid and crystalloid scintillation methods.关键词：radio-paper chromatograph;Scanning;Background;Efficiency;localization resolving power radiochemical purity Rf value
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发布时间：2022-09-13 - 摘要：The power calibration of the zero-power reactor of uranium water lattice can be derived from the total fission rate of the whole reactor. The total fission rate depends on the thermal neutron flux at certain point of the reactor core, fuel cadmium ratio. 235U fission cross section, 235U nuclear number in the whole reactor and the relative distribution of the fission rate in the reactor core. In this paper the thermal neutron flux in certain point of the reactor core, the total fission rate of the whole reactor and the reactor power have been determined.关键词：power calibration;zero-power reactor;active absolute measurement;codmium ratio
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发布时间：2022-09-13 - 摘要：The proliferative effect of hyperlipemic serum with or without Chinese herb medicine pollen typhae was compared in vitro. 3H-TdR was incorporated to DNA of cultured cells of smooth muscle of rabbit aorta. Radioactivity of DNA was determined by liquid scintillation counting (cpm) and the percentage of labelled nuclei was determined by autoradiography. It was found that the counting and the percentage of labelled nuclei were low in the cultured smooth muscle cells when hyperlipemic sera were added with pollen typhae than hyperlipemic sera were added alone. The results demonstated that pollen typhae has inhibiting effect on the stimulating action of hyperlipemic serum upon cells of smooth muscle.关键词：aortic smooth muscle cell;Autoradiography;hyperlipemic serum;low density lipoprotein;platelet derived growth factor;pollen typhae;Liquid scintillation counting
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发布时间：2022-09-13 - 关键词：environmental radiochemistsy;environmetal contamination;environmental monitoring;environmental analytical chemistry
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发布时间：2022-09-13
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