最新刊期
      卷 39 ， 期 8 ， 2016
      • Pei HUANG,Minjun LI,Gang ZUO,Haojie GUO,Huan ZHOU,Muyun XIE,Feng YU,Chunyan XU,Jianhua HE
        Vol. 39, Issue 8, Article number: 080101(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.080101
        摘要：Background: Fatty acid binding protein 4 (FABP4), as fatty acid chaperone, plays center roles in lipid transport, lipolysis and liposynthesis, and it has been proved to be involved in the lipid signaling and inflammatory responses. Inhibitors of FABP4 are promising treatments for the diabetes and atherosclerosis. Purpose: The aim is to reveal the structural conformation of aspirin and salicylic acid binding to the FABP4, and to explore the novel structural features for the design of high-selective FABP4 inhibitors. Methods: Single crystal X-ray diffraction is applied to solve the structure of the ligand-protein complexes. Results: We have determined the crystal structures of FABP4 in complex with aspirin and its derivative, and from which a special C-H-πinteraction between the residues Phe16, Arg126 and the benzyl ring of aspirin has been defined. Conclusion: The complex structures of FABP4 bound with aspirin and its derivative show that the edge-to-face C-H-πinteraction between the residues Phe16, Arg126 and the benzyl ring of aspirin is a critical intermolecular force between the ligand-FABP4 interactions, which enables us to consciously apply these interactions in hit and lead optimization in rational structure based drug design.  
        关键词：FABP4;Protein crystallography;C-H-πinteraction   
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        发布时间：2021-05-24
      • Xinyu TONG,Chuanqian PENG,Yumei HE,Jie WANG
        Vol. 39, Issue 8, Article number: 080102(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.080102
        摘要：Background: The Long Trace Profiler (LTP) has been widely used to measure the profile of optical mirrors used in synchrotron radiation applications. The Root Mean Square (RMS) of profile error from fitted profile is used to evaluate the quality of mirror. Purpose: This study aims to find a better fitting algorithm for measurement data of LTP and minimize system errors generated by fitting. Methods: Least square method (LSM) based on the algebraic distance, LSM based on geometric distance, and genetic algorithm have been compared for simulation profiles of the measured data of LTP with different radii, noise intensities and postures. Results: Simulation results showed that fitting algorithm of least-squares orthogonal geometric distances had a good noise robustness, and insensitiveness to the mirror's postures. Conclusion: Least-squares orthogonal distances is the most suitable curve fitting algorithm for LTP, it provides references for the profile testing of optical mirrors at SSRF.  
        关键词：LTP;Curve fitting algorithm;Synchrotron radiation;Surface quality   
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        发布时间：2021-05-24
      • Chao WANG,Jun XIAO,Pan WANG,Yingying LI,Ziyue LI,Xiaobing LUO
        Vol. 39, Issue 8, Article number: 080201(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.080201
        摘要：Background: As a kind of important fission material, the accurate quantification of 238U is of great significance in the measurement of fission yield data. Purpose: The aim is to nondestructively measure the content of 238U by using the activation method. Methods: Neutron of 483-keV produced by the reaction of T(p, n)3He induces 238U occurring radiative capture reaction on the 2.5-MeV electrostatic accelerator of Sichuan University. The atomic number of 238U in uranium samples is measured by using 278-keV gamma ray of 239Np on the detector of high purity germanium (HPGe) and the data of capture cross section. Results:The deflections which were caused by multiple scattering and self-shielding of the target and sample in the experiment were corrected with MCNPX (Monte Carlo N-Particle eXtended). The result of the experiment is that the atomic number of238U in the 2.884 2-g metal uranium is 5.712 8×1021. Conclusion: The uncertainty of the experimental result is 4.1%. We can reduce the effect of multiple scattering effects and self-shielding by decreasing the thickness of the bottom lining, target tube, water layer and cladding material of the sample.  
        关键词：Quantification analysis of 238U;Data of capture cross section;Monte Carlo correction   
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        发布时间：2021-05-24
      • Haifeng LI,Xiaojun ZHANG,Yungang LI,Jinming ZHANG
        Vol. 39, Issue 8, Article number: 080301(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.080301
        摘要：Background: The FDG 18F-fluorodeoxyglucose (18F-FDG) synthesis module was obtained by one process of production generally. The adjusting of synthetic technology would have a significant influence on the quality of product. Purpose: In order to solve the problem and optimize the production process, in this paper, the domestic FDG synthesis module has been improved. Methods:The domestic FDG synthesis module of basic hydrolysis was optimized by removing the components of automatic alkali-adding and on-column hydrolysis. The influencing factors of synthesis process were discussed, including the time of nucleophilic reaction, the amount of HCl, the hydrolysis time and the residual solvents. Results:It took 27 min from 18F-to final product of 18F-FDG, and a radiochemical yield of 60.27%±2.29% (n=37, End of Synthesis (EOS)) was obtained. The radiochemical purity of 18F-FDG was higher than 98% and the radioactivity was (29.15±3.09) GBq (n=37). Conclusion: The synthetic process was reliable and automated, and the product was suitable for clinical use. Finally, two different processes were used for synthesizing 18F-FDG on the same module.  
        关键词：18F-FDG;Automated synthesis;PET/CT (Positron emission tomography/computer tomography);Quality control   
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        发布时间：2021-05-24
      • Songtao XIAO,He YANG,Tian LAN,Xiechun LIU,Li LI,Huibo LI,Yan WANG
        Vol. 39, Issue 8, Article number: 080302(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.080302
        摘要：Background: Plutonium was one of the most radionuclides and the reducing of Pu(Ⅳ) had been researched extensively. It was one of the main research directions that Pu(Ⅳ) was reduced by hydrazine derivatives. Purpose:The direction of the study of the separation of Np(Ⅵ) from Pu(Ⅳ) could be pointed out and crucial basic data for it could be obtained by the study of the quantitative structure-activity relationships (QSAR) between the half-reaction times of reducing Pu(Ⅳ) and their physicochemical parameters. Methods: 3D structure of hydrazine derivatives was optimized and their energy was calculated by density functional theory (DFT) with B3LYP method and 6-311+(3d, 3p) basis set and the most stable structure was obtained. The physicochemical parameters such as hydrophobic parameters etc. that can describe the structure were gained by HyperChem. Results:The interconnectedness between the half-reaction times and their physicochemical parameters was analyzed, and the QSAR equation with a good correlation is obtained, finally. Conclusion:The result showed that the hydrophobic parameter was the most important factor affecting the reduction rate of Pu(Ⅳ) by hydrazine derivatives, and was negatively correlated with Pu(Ⅳ) reduction rate.  
        关键词：Hydrazine derivatives;Pu(Ⅳ);Reduction rate;QSAR   
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        发布时间：2021-05-24
      • Fengle DAI,Hongtao WANG,Shihao ZHANG,Ming XUE,Jianhua DING,Zichao JIANG
        Vol. 39, Issue 8, Article number: 080501(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.080501
        摘要：Background: Magnesium phosphate cement (MPC) has a good application prospect in radioactive waste solidification for its good adsorption property of Sr and Cs which are the main elements in the middle and low level nuclear reactor waste. Purpose: This study aims to investigate the migration of radionuclides in MPC and build a transport model of Sr2+, Cs+ in MPC. Methods: According to Fick's second law, the migration model of Sr2+, Cs+ to predict the leaching behavior of Sr2+, Cs+ was established by studying the leach abilities of Sr2+ and Cs+ in MPC. Results: Sr and Cs can be effectively solidified by MPC, and the leaching rate of Sr2+, Cs+ is low. Compared with Sr2+, Cs+ has stronger migration ability in magnesium phosphate cement. Conclusion:The leaching behavior of Sr2+, Cs+ immobilized in MPC can be predicted well by one-dimension decay migration model. In addition, the migration behavior of Sr2+ was predicted more accurately by the migration model.  
        关键词：MPC;Immobilize;Leaching rate;Migration model   
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        发布时间：2021-05-24
      • Qinglei LIANG,Bo XING,Bin YING,Jinghuai LI,Xuesheng LYU,Guorong LIU
        Vol. 39, Issue 8, Article number: 080502(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.080502
        摘要：Background:Uranium enrichment of on-line monitor (UEOM) is an equipment which is adopted to measure enrichment of UF6 flowing through the processing pipes at uranium enrichment plant. Background is the key parameter which directly influences the measurement precision. Traditional background measurement methods need to stop work of monitor and vacuum container. Purpose: This study aims to build up a method to measure the background of monitor automatically. Methods: A NaI(T1) detector is used to measure the count rates ofγ-ray emitted from 235U and a pressure sensor is used to measure the pressure of gases in the container, the background of monitor is obtained by fitting the data of different pressures. Results: The experimental results show that the relative standard deviation is less than 0.30% and the maximum deviation is less than 0.25% comparing with the data from mass spectrometry method. Conclusion: The new method shows a better precision compared with the traditional and it increases automation of the monitor greatly.  
        关键词：On-line monitor;Background;Uranium enrichment;Automation   
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        发布时间：2021-05-24
      • Lei WANG,Chuangxiong CAI,Jing ZHAO,Zhaozhong HE,Kun CHEN
        Vol. 39, Issue 8, Article number: 080601(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.080601
        摘要：Background: A molten salt natural circulation experimental loop was developed to study characteristics of the molten salt natural circulation and support the design of passive safety systems of advanced molten salt reactors. Purpose: The heat loss of the loop may affect the molten-salt natural circulation profoundly, thus, it is necessary to quantify the heat loss. Methods:A series of heat loss experiments were conducted on the salt storage tank of the natural circulation loop and the heat losses were also calculated using numerical methods. Based on the measured and calculated results, we obtained the relations between the power of the heat loss and the temperature and the cooling time. Results: It was found that the calculated values of the power of the heat loss were in good agreement with the measured ones. The difference is within 10% for all temperatures concerned. Conclusion: The thermal insulation design of the molten salt natural circulation experimental loop limits the heat loss successfully. An intrusive heating device, though widely adopted, may become a major heat loss channel when not in use, and lead to the molten salt temperature stratification.  
        关键词：Molten salt;Heat loss;Thermal insulation;Heater;ANSYS CFX   
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        发布时间：2021-05-24
      • Bo SUN,Jinhao ZHOU,Changfeng SHE,Qiang DOU,Dewu LONG,Weiqing HU,Qingnuan LI
        Vol. 39, Issue 8, Article number: 080602(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.080602
        摘要：Background: During dry reprocessing of spent nuclear fuel in the molten salt reactor, the processing equipment is confronted with serious material corrosion problems. The molten salt frozen-wall technique has been proposed as an effective method to protect the equipment from chemical corrosion whilst stability of frozen wall thickness is the key to success in the application of frozen wall technique for dry reprocessing. Purpose:This paper aims to study the influence of key factors in the application of molten salt frozen wall. Methods: Based on the homemade experimental apparatus of frozen wall, the application of molten salt frozen wall during dry reprocessing was simulated. The influences of inlet temperature of oil, initial temperature of molten salt, heater power and initial thickness of frozen wall on the change of frozen wall in the process were analyzed, as well as the reasons behind the change of the thickness of frozen wall via the change of the heat flux. Results:The influence laws of main factors are obtained, and the optimum condition for use is obtained. Experimental data fitting results show the relationship between the heat flux of the unit length and the thickness of the frozen wall, and the average relative error rate is 11.2%. Conclusion:The greater heat flux is, the more frozen wall disappears. When equilibrium is reached, the greater the heat flux is, the smaller thickness of the frozen wall will be.  
        关键词：Frozen wall;Dry reprocessing;Molten salt reactor   
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        发布时间：2021-05-24
      • Huaping DONG,Wenyuan FAN,Yun GUO
        Vol. 39, Issue 8, Article number: 080603(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.080603
        摘要：Background: Plate-type assembly is widely used in research reactors. Flow distribution inside the assembly is a key factor in design process. Computational fluid dynamics (CFD) method is an important way for flow distribution calculations. However, huge requirements on computing resources limit the application scope of CFD method. Purpose: The aim is to invest the CFD method in the flow distribution with smaller requirements on computing resources. Methods:New developed CFD method by partial modeling and iterating is used. Results: Using the traditional CFD and newly developed method, flow distribution calculations are done toward plate-type assembly with and without the flow distributor, and the maximum differences are 0.81% and 0.56%, respectively. Conclusion:The partial modeling and iterating method could optimize CFD simulations on flow distribution of plate-type assembly accurately, economically and quickly.  
        关键词：Plate-type assembly;Flow distribution;CFD   
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        发布时间：2021-05-24
      • Deng PAN,Xiaohan YU,Yang ZOU,Yanzhi E,Bo XU,Zhenhua ZHOU,Jie HE
        Vol. 39, Issue 8, Article number: 080604(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.080604
        摘要：Background:The computational fluid dynamics (CFD) simulation of thermal-hydraulic characters is essential to ensure the safety in designing and operating a nuclear reactor. To obtain reliable results, a suitable model must be chosen. For the pebble bed reactors, the complex geometries of the core make it difficult to establish a precise model for CFD simulation, especially for the molten salt reactor (MSR)-one of the most hopeful GIV nuclear power system. Purpose:This study is aimed to valid the porous media model used in pebble beds thermal-hydraulic simulation, including the Pressure-Drop formula and the Convection-Heat-Transfer formula. Methods: The fluent model of an orderly-arranged pebble bed was built, and the SST-turbulence model was chosen to simulate the molten salt flow inside the bed. Results: In a large range of fluid Reynolds numbers, the linear pressure drop of the flow was obtained, and also was the Nusselt numbers for convection heat transfer between sphere surface and the salt fluid. Conclusions: The data was fitted to format new formulas. For the pressure drop, simulation result much differs in both of the KTA (Kerntechnischer Ausschuss)-formula and the Ergun-equation. However, the Nusselt number from simulation is more close to the KTA-formula and the Wakao-formula. Modification of the traditional formulas is needed obviously, and new formulas fitted from KTA-formula is much more close to the simulation results, both for the linear pressure drop and the Nusselt number.  
        关键词：Pebble bed reactor;MSR;CFD simulation;Porous media model   
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        发布时间：2021-05-24
      • Yalan PAN,Xiuchun LUAN,Zhe WANG,Jiaxu ZUO,Wei SONG
        Vol. 39, Issue 8, Article number: 080605(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.080605
        摘要：Background:The Steam Generator Tube Rupture (SGTR) accident, which has its own characteristics, is one of the important accidents in nuclear power plants, and it is significant to the safety of the nuclear power station. Purpose: In this paper, AP1000 reactor is selected as the typical advanced passive nuclear power plant to analyze the core damage consequence caused by SGTR accident, so as to find out the weak links existing in the system. Methods: The Probabilistic Safety Assessment (PSA) method in level one has been used to analyze the SGTR accident in AP1000. After the power plant accident occurs, systems, equipment and personnel respond differently, event tree analysis method is used to obtain sequence, and the systems related to this accident are analyzed by fault tree models. Results: By the Risk Spectrum software, the total Core Damage Probability (CDF) has been calculated, and the minimal cut sets, the importance measures and the sensibility of the core damage have also been analyzed respectively. Conclusion:According to a series of analysis results, the most important basic events resulting in the core damage can be obtained, and the weak link of the system can be found, which has a certain theoretical support for the further strengthening of accident prevention and mitigation of the core damage caused by the accident.  
        关键词：Advanced passive nuclear power plants;SGTR;CDF;PSA   
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        发布时间：2021-05-24
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