最新刊期
卷 0 ， 期 0 ， 2020
- 摘要：In situ high-pressure experiments of lizardite have been conducted by means of synchrotron X-ray diffraction with diamond anvil cell at room temperature.No phase transition occurs in the pressure range up to 31.9 GPa.Isothermal equation of state of lizardite can be well expressed by third-order Birch-Murnaghan equation of state,obtaining V0= 353.2(7)3,K0= 75(3) GPa,K0’= 3.4(2)(BSRF data) and V0= 356.5(6)3,K0= 69(3) GPa,K0’= 3.1(3)(SSRF data).These two sets of data show basically good consistency to each other.Anisotropy exists on axial compressibility of lizardite(Kc>Kb≈Ka),which can be ascribed to the layered structure of lizardite.The direction vertical to the structure layer are more compressible because the structure layers are collected by hydrogen bonds;while the direction parallel to the structure layer is less compressible for the reason of covalent bonds and ionic bonds.关键词：Lizardite;High pressure;Structure;Compressibility
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发布时间：2021-03-05 - 摘要：Pr0.7Sr0.3MnO3/La0.5Ca0.5MnO3/Pr0.7Sr0.3MnO3(PSMO/LCMO/PSMO) trilayers were deposited on(001)-oriented single crystal MgO by pulsed laser deposition.The thickness of both PSMO layers was 36 nm while the thickness of LCMO layer was 6,12,18,24,30 and 36nm,respectively.Out-of-plane and in-plane lattice parameters of trilayers were obtained by using symmetric scanning and asymmetric scanning mode of high resolution X-ray diffraction.Strain states of trilayers have been studied.The results showed that strain relaxation states of trilayers were decided by bulk strain and Jahn-Teller(JT) strain together.The mechanism for strain relaxation in trilayers is different from that for tetragonal distortion.The competition between bulk strain and Jahn-Teller(JT) strain played an important role in the magnetotransport and magnetic properties of trilayers.关键词：Pr0.7Sr0.3MnO3/La0.5Ca0.5MnO3/Pr0.7Sr0.3MnO3 trilayers;High resolution X-ray diffraction;Strain
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发布时间：2021-03-05 - 摘要：In the CSNS/RCS LLRF remote control prototype based on EPICS/vxWorks,one CPU board controls eight FPGA-based I/O board via cPCI bus,and transfer data to host computer to display.Meanwhile,host computer can also transfer control signal and waveform data downstream.Test result indicates that this prototype will satisfy the requirement of CSNS/RCS LLRF control system.
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发布时间：2021-03-05 - 摘要：To study intense beam transfer in electrostatic quadrupole,the matrix method was applied to analyze the transport matrixes in electrostatic quadrupole of non-intense beam and intense beam respectively,and a computer code was written for the pulsed beam transporting in electrostatic quadrupole.Optimization techniques were used to solve for the given optical conditions and iteration procedures were adopted to obtain self-consistent solutions in this computer code.The calculations were made by using the code and other codes under the condition of different beam currents,and the simulation results were compared and analyzed.The results show that the more intense the beam current,the more powerful the space-charge effect and the greater the deviation of non-self-consistent solution and self-consistent solution.关键词：Intense pulsed beam;Electrostatic quadrupole;Space-charge effect;Iteration method;Transport simulation
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发布时间：2021-03-05 - 摘要：This paper describes the experimental procedures,testing information and application advantages when neutron radiography is used for non-destructive inspections and quantitative analysis of fuel elements from nuclear power plants.Both the 235U enrichment and the material distribution inside the pellets can be determined by neutron radiography methods for the non-irradiated fuel elements.Both the structural integrity of fuel elements for different reactors such as PWR,BWR,FBTR and the hydrogen accumulation in the cladding material can be inspected for the irradiated samples.关键词：Neutron radiography;Nuclear fuel element;Non-destructive testing
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发布时间：2021-03-05 - 摘要：Design and fabricate a new test structure of bipolar device: the gate controlled later PNP bipolar transistor(GCLPNP BJT),then sealed it together with the normal lateral PNP bipolar transistor which is made under the same manufacture process.Then 60Co-γ radiation effects and annealing behaviors of these two structures are investigated.The results show that the response about base current,collector current,access base current and normalized current gain of GCLPNP bipolar transistor are almost identical to the normal one.Radiation induced defects in the GCLPNP bipolar transistor is separated quantitatively.Studying on the quantitative change of radiation induced defects in the domestic gate controlled bipolar transistor should be a useful way to research the change of radiation induced charges of normal PNP bipolar transistor.关键词：PNP bipolar transistor;60Co-γ irradiation;Radiation induced charges;Charge separation
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发布时间：2021-03-05 - 摘要：Stability of synchronized motion of the particle beams can be affected by high-frequency voltage disturbance and beam cooling.In this paper,using classical mechanics and small amplitude approximation,the particle motion equation is reduced to the generalized Duffing equation with the parametric excitation,while using the Melnikov method,the bifurcation nature of the periodic orbits and the chaotic behavior of the heteroclinic orbits are analyzed to derive the critical conditions for a stable system.The results show that stable synchronized motion of the particle beams can be achieved by adjusting the parameters.关键词：Voltage modulation;Beam cooling;Parametric excitation;Bifurcation;Chaos
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发布时间：2021-03-05 - 摘要：The accurate measurement of dose rate is the key issues to obtain reliable ESR age.In this article,we used X-ray fluorescence spectrometry to determine the U,Th,K content of the fluvial sediments.And the standard working curves were established using the national rock reference material.Setting the lower X-ray power and the matrix effect,U,Th,K content in the fluvial sediment were investigated.The results show that the method recovery rate of U and Th is less than 15 %.Comparing with the measurement data from the α-counting and Atomic Spectrometry analysis,the dose rate difference is less than 5 %.It shows that the X-ray fluorescence spectrometry method can fit for the requirement for obtaining the U,Th,K content of fluvial sediment for ESR dating.关键词：Environmental Dose;ESR;X-ray fluorescence spectrometry Method;Fluvial Sediments
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发布时间：2021-03-05 - 摘要：The EGSnrc/DOSRZnrc Monte Carlo program was used to calculate the absorbed dose to the quartz,the feldspar and the aluminum oxide slice samples irradiated by a 90Sr-90Yβ source.The distributions of the β absorbed dose with depth in the slice samples were evaluated,and the effects of the material and the thickness of the slice samples on the absorbed dose were discussed.Results show that for the quartz,the feldspar or the aluminum oxide slice samples with thickness ranging from 10 to 500μm,the maximum differences of the relative dose can be up to 10%,8% and 16%,respectively.However,for the quartz or the feldspar slice samples with thickness between 100 and 300μm,and for the aluminum oxide slice samples with thickness between 100 and 200μm,the maximum differences of the relative dose are all less than 4%.关键词：Luminescence;dating;β absorbed dose;Monte Carlo simulation
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发布时间：2021-03-05 - 摘要：According to fundamental parameter method theory,gained the key parameters such as mass-absorption coefficients and excitation factors and wrote the calculation procedure.In experiment,a series of lead brass alloy standard samples were analyzed with an energy dispersive X-ray fluorescence spectrometer and calculated the contents of Cu、Zn of the samples via the fundamental parameter calculation procedure.The result shows the fundamental parameter method can overcome the absorption-enhancement effect between Cu and Zn elements well.The measured contents of Cu and Zn is respectively 54%–64% and 33%–45%,the precision of the method is 0.10% and 0.15 % respectively for Cu and Zn.关键词：Energy dispersive X-ray fluorescence analysis;Fundamental parameters method;Lead brass alloy;Absorption enhancement effect
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发布时间：2021-03-05 - 摘要：In the litho-density logging,formation density and lithology were acquired by calculating the total counts in certain energy window.Therefore,the division of the energy window directly affects the evaluation of density and lithology value.In the process of the energy window division,mud type affects the determination of the range of energy window.In this work,Monte Carlo simulation method was applied to study the range of energy window regarding to water mud and barite mud,respectively.The results show that the range of the energy window with barite mud is less than that of the water mud,and lithology identification will have greater error in the barite mud.It is important to analyze influencing factors and improve the measurement accuracy of the litho-density logging.关键词：Formation density;Lithology;Energy window division;Water mud;Barite
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发布时间：2021-03-05 - 摘要：Ge γ-ray spectrometer is an important tool for determining potassium,uranium and thorium contents in sediments.The results depend on accuracy of the calibration and the extent to which the measuring conditions resemble those adopted during calibration.Our ORTEC GEM70 P4-95 P type Ge γ-ray spectrometer was calibrated by measuring K,Ra,Th and U standards from Ionizing Radiation Division National Institute of Metrology.Different type samples were analyzed by both ICP-MASS and the Ge γ-ray spectrometer.The results show that 8 hours measured time are enough and the calibration is accurate.关键词：Ge γ-ray spectrometer;Radioactivity nuclide;Dose rate;Calibration
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发布时间：2021-03-05 - 摘要：Nowadays,the measurement for radon concentration and radon daughters potential ɑ energy concentration has gained more and more attention.This paper introduces the basic principle for ’Markov’ method in details.A hardware and software of the radon measure instrument by balloon has also been described.This system integrated Au-Si surface barrier detector and dc vacuum pump and designed a pneumatic switch valve.With the switch valve,the direction of gas path can be changed conveniently without the balloon being taken down.This instrument has an internal temperature and humidity sensor and ARM7 microprocessor as the logic core.It can store 2000 groups of data in the system.Meanwhile this Radon instrument has been tested in standard radon chamber of South China University and the results showed that the new developed balloon method measure radon apparatus could be applicable because of its easy use,great reliability and performance stability.关键词：Radon concentration;Radon daughters potential alpha energy concentration;Markov method;Balloon radon method;Embedded system
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发布时间：2021-03-05 - 摘要：The solid state nuclear track detectors(SSNTDs) are used very extensive in the radiation research and radiation protection dosimetry in many domains.As the necessary member of that,CR-39 detectors have been popular between scientific research workers preference in recent years.This paper briefly introduces and compares with several commonly used neutron solid state nuclear track detector,and introduces the CR-39 detectors and its etching methods emphatically and summarizes the main factors that effect the etching rate of the CR-39 neutron detectors,this paper expounds the importance of etching technology for CR-39 detectors and prospects its application in other fields.关键词：CR-39 Detectors;Etching;Influencing factors
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发布时间：2021-03-05 - 摘要：Typical operational transients have been analyzed with RELAP5 code for AP1000 NPP,in which the reactor power control system was simulated,including Reactor Control System(RECS),Rapid Power Reduction(RPR),Steam Dump Control System(SDCS),Feedwater Control System(FWCS),Pressurizer Pressure Control System(PPCS) and Pressurizer Level Control System(PLCS).It indicates that the plant control system is effective to bring the plant into a safe steady state without actuation of reactor protection system under the representative operational transient,only depends upon the plant control system adjustment.Analysis results show that the design requirement will be met for AP1000 operational transient.关键词：Plant operational transient;Step/Ramp load change;Reactor power control system;RELAP5 code
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发布时间：2021-03-05 - 摘要：Acupuncture is a procedure in which fine needles are inserted into an individual at discrete points and then manipulated,with the intent of treating disease.Acupuncture is practiced worldwide,despite difficulties in reconciling its principles with evidence-based medicine.Here we studied the effect of acupuncture treatment on motor function and its underlying mechanism in mouse model of Parkinson’s Disease(PD) using 1-methyl-4-phenyl-1,2,3,6-terahydropyridine(MPTP).We found that acupuncture treatment at acupoint GB34 improved motor function of model mice.We also found evidence that lysosomal membranes were repaired and ɑ-synuclein was degraded,suggesting that the autophagy level of PD model mice was increased.This study reveals a new possible mechanism of acupuncture treatment.关键词：Acupuncture;Parkinson’s Disease;GB34;Autophagy
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发布时间：2021-03-05
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