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Quantitative energy-dispersive X-ray fluorescence analysis for unknown samples using full-spectrum least-squares regression

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Nuclear Science and Techniques 2019年第3期30卷 149-159页

作者： Yong-Li Liu qing-xian zhang Jian zhang Hai-Tao Bai Liang-Quan Ge The College of Applied Nuclear Technology and Automation Engineering Chengdu University of Technology

The full-spectrum least-squares(FSLS) method is introduced to perform quantitative energy-dispersive X-ray fluorescence analysis for unknown solid *** on the conventional least-squares principle, this spectrum evaluation method is able to obtain the background-corrected and interference-free net peaks, which is significant for quantization analyses. A variety of analytical parameters and functions to describe the features of the fluorescence spectra of pure elements are used and established, such as the mass absorption coefficient, the Gi factor, and fundamental fluorescence formulas. The FSLS iterative program was compiled in the C language. The content of each component should reach the convergence criterion at the end of the calculations. After a basic theory analysis and experimental preparation, 13 national standard soil samples were detected using a spectrometer to test the feasibility of using the algorithm. The results show that the calculated contents of Ti, Fe, Ni, Cu, and Zn have the same changing tendency as the corresponding standard content in the 13 reference samples. Accuracies of 0.35% and 14.03% are obtained, respectively, for Fe and Ti, whose standard concentrations are 8.82% and 0.578%, respectively. However, the calculated results of trace elements (only tens of lg/g) deviate from the standard values. This may be because of measurement accuracy and mutual effects between the elements.

关键词： Energy-dispersive X-ray fluorescence analysis Full-spectrum least-squares method Effective atomic number Mass attenuation coefficient Fundamental parameter method

Design and preliminary test of tritiated water online detector system based on plastic scintillators

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Nuclear Science and Techniques 2022年第10期33卷 68-78页

作者： Chun-Hui Dong Kai-Yong Liao Rui-Yang Xu Hong-Wu Liu qing-xian zhang Chengdu University of Technology Chengdu 610059China

In this study,an online detector system based on plastic scintillators is designed to monitor the activity of tritiated water in the liquid effluents of nuclear power *** feasibility of the detector is verified via simulation on Geant4,and the optimal detector structure size is determined.A back-end electronics system is designed and an experimental measurement platform forβ-rays based on a ^(40)KCl solution is *** ^(40)KC solutions with different activities ranging from 10 to4500 Bq/L are measured,and 1300 V is determined as the optimal operating high voltage of the photomultiplier tubes.A linear fit is performed in 10-min counts,and the maximum linear goodness of fit(R^(2))achieved is ***-term stability measurements are performed for two detectors,one filled with air and the other with a ^(40)KCl solution exhibiting an activity of 2000 Bq/*** relative deviation of the counts of the detector system every 10 min is 0.998%when the ^(40)KCl solution is used,and the maximum Gaussian R^(2) of the counts is 0.9849.

关键词： Tritiated water Geant4 Plastic scintillator Electronics system

The study of a neutron spectrum unfolding method based on particle swarm optimization combined with maximum likelihood expectation maximization

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Nuclear Science and Techniques 2023年第4期34卷 149-160页

作者： Hong-Fei Xiao qing-xian zhang He-Yi Tan Bin Shi Jun Chen Zhi-Qiang Cheng Jian zhang Rui Yang Applied Nuclear Technology in Geosciences Key Laboratory of Sichuan Province Chengdu University of TechnologyChengdu 610059China National Key Laboratory for Metrology and Calibration Techniques China Institute of Atomic EnergyBeijing 102413China

The neutron spectrum unfolding by Bonner sphere spectrometer(BSS) is considered a complex multidimensional model,which requires complex mathematical methods to solve the first kind of Fredholm integral equation. In order to solve the problem of the maximum likelihood expectation maximization(MLEM) algorithm which is easy to suffer the pitfalls of local optima and the particle swarm optimization(PSO) algorithm which is easy to get unreasonable flight direction and step length of particles, which leads to the invalid iteration and affect efficiency and accuracy, an improved PSO-MLEM algorithm, combined of PSO and MLEM algorithm, is proposed for neutron spectrum unfolding. The dynamic acceleration factor is used to balance the ability of global and local search, and improves the convergence speed and accuracy of the algorithm. Firstly, the Monte Carlo method was used to simulated the BSS to obtain the response function and count rates of BSS. In the simulation of count rate, four reference spectra from the IAEA Technical Report Series No. 403 were used as input parameters of the Monte Carlo method. The PSO-MLEM algorithm was used to unfold the neutron spectrum of the simulated data and was verified by the difference of the unfolded spectrum to the reference spectrum. Finally, the 252Cf neutron source was measured by BSS, and the PSO-MLEM algorithm was used to unfold the experimental neutron *** with maximum entropy deconvolution(MAXED), PSO and MLEM algorithm, the PSO-MLEM algorithm has fewer parameters and automatically adjusts the dynamic acceleration factor to solve the problem of local optima. The convergence speed of the PSO-MLEM algorithm is 1.4 times and 3.1 times that of the MLEM and PSO algorithms. Compared with PSO, MLEM and MAXED, the correlation coefficients of PSO-MLEM algorithm are increased by 33.1%, 33.5% and 1.9%, and the relative mean errors are decreased by 98.2%, 97.8% and 67.4%.

关键词： Particle swarm optimization Maximum likelihood expectation maximization Neutron spectrum unfolding Bonner spheres spectrometer Monte Carlo method

Verification of a self-developed CFD-based multi-physics coupled code MPC-LBE for LBE-cooled reactor

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Nuclear Science and Techniques 2021年第5期32卷 84-100页

作者： Zhi-Xing Gu qing-xian zhang Yi Gu Liang-Quan Ge Guo-Qiang Zeng Mu-Hao zhang Bao-Jie Nie College of Nuclear Technology and Automation Engineering Chengdu University of TechnologyChengdu 610059China Sino-French Institute of Nuclear Engineering and Technology Sun Yat-Sen UniversityZhuhai 519082China

To perform an integral simulation of a pool-type reactor using CFD code,a multi-physics coupled code MPC-LBE for an LBE-cooled reactor was proposed by integrating a point kinetics model and a fuel pin heat transfer model into self-developed CFD *** code verification,a code-to-code comparison was employed to validate the CFD ***,a typical BT transient benchmark on the LBE-cooled XADS reactor was selected for verification in terms of the integral or system *** on the verification results,it was demonstrated that the MPC-LBE coupled code can perform thermal-hydraulics or safety analyses for analysis for processes involved in LBE-cooled pool-type reactors.

关键词： LBE-cooled pool-type reactor Computational fluid dynamics Multi-physics coupling code Safety analysis code Verification

Fast nuclide identification based on a sequential Bayesian method

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Nuclear Science and Techniques 2021年第12期32卷 116-127页

作者： Xiao-Zhe Li qing-xian zhang He-Yi Tan Zhi-Qiang Cheng Liang-Quan Ge Guo-Qiang Zeng Wan-Chang Lai Chengdu University of Technology The College of Nuclear Technology and Automation EngineeringChengdu 610059China

The rapid identification of radioactive substances in public areas is ***,traditional nuclide identification methods only consider information regarding the full energy peaks of the gamma-ray spectrum and require long recording times,which lead to long response *** this paper,a novel identification method using the event mode sequence(EMS)information of target radionuclides is *** EMS of a target radionuclide and natural background radiation were established as two different probabilistic models and a decision function based on Bayesian inference and sequential testing was *** proposed detection scheme individually processes each *** a photon is detected and accepted,the corresponding posterior probability distribution parameters are estimated using Bayesian inference and the decision function is ***,value of the decision function is compared to preset detection thresholds to obtain a detection ***ments on different target radionuclides(137Cs and 60Co)were *** count rates of the regions of interest(ROI)in the backgrounds between[651,671],[1154,1186],and[1310,1350]keV were 2.35,5.14,and 0.57 CPS,*** experimental results demonstrate that the average detection time was 6.0 s for 60Co(with an activity of 80400 Bq)at a distance of 60 cm from the *** average detection time was 7 s for 137Cs(with an activity of 131000 Bq)at a distance of 90 cm from the *** results demonstrate that the proposed method can detect radioactive substances with low activity.

关键词： Natural radiation Nuclide identification Sequential testing Nuclear safety

Method for rapid warning and activity concentration estimates in online waterγ-spectrometry systems

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Nuclear Science and Techniques 2024年第3期35卷 1-12页

作者： Meng Wang Yi Gu Mao-Lin Xiong Liang-Quan Ge qing-xian zhang Guo-Qiang Zeng Heng Lu Sheng-Liang Guo College of Nuclear Technology and Automation Engineering Chengdu University of TechnologyChengdu 610059China Applied Nuclear Technology in Geosciences Key Laboratory of Sichuan Province (Chengdu University of Technology)Chengdu 610059China Chengdu New Ray Technology Co.Ltd Chengdu 610052China

Onlineγ-spectrometry systems for inland waters,most of which extract samples in situ and in real time,are able to produce reliable activity concentration measurements for waterborne radionuclides only when they are distributed relatively uniformly and enter into a steady-state diffusion regime in the measurement *** protect residents’health and ensure the safety of the living environment,better timeliness is required for this measurement *** address this issue,this study established a mathematical model of the online waterγ-spectrometry system so that rapid warning and activity estimates can be obtained for water under non-steady-state(NSS)*** addition,the detection efficiency of the detector for radionuclides during the NSS diffusion process was determined by applying the computational fluid dynamics technique in conjunction with Monte Carlo *** this basis,a method was developed that allowed the online waterγ-spectrometry system to provide rapid warning and activity concentration estimates for radionuclides in *** analysis of the NSS-mode measurements of^(40)K radioactive solutions with different activity concentrations determined the optimum warning threshold and measurement time for producing accurate activity concentration estimates for *** experimental results show that the proposed NSS measurement method is able to give warning and yield accurate activity concentration estimates for radionuclides 55.42 and 69.42 min after the entry of a 10 Bq/L^(40)K radioactive solution into the measurement chamber,*** times are much shorter than the 90 min required by the conventional measurement ***,the NSS measurement method allows the measurement system to give rapid(within approximately 15 min)warning when the activity concentrations of some radionuclides reach their respective limits stipulated in the Guidelines for Drinking-water Quality of the WHO,suggesting that this method con

关键词： Water radioactivity monitoring Dynamic detection efficiency Rapid warning Activity estimation

Inhibition of proliferation of prostate cancer cell line, PC-3, in vitro and in vivo using （-）-gossypol

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Asian Journal of Andrology 2010年第3期12卷 390-399,I0011页

作者： xian-qing zhang Xiao-Feng Huang Shi-Jie Mu Qun-Xing An Ai-Jun Xia Rui Chen Dao-Cheng Wu The Key Laboratory of Biomedical Information Engineering of Ministry of Education Xi ＇an Jiaotong University Xi ＇an 710038 China Department of Blood Transfusion Xij＇ing Hospital Xi ＇an 710032 China Central Laboratory Fourth Military Medical University Xi＇an 710032 China

We investigated the antiproliferative activity of （-）-gossypol on the human prostate cancer cell line PC3 in vitro and in vivo to elucidate its potential molecular mechanisms. Cell growth and viability were evaluated using the 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide （MTT） assay, and cell apoptosis was detected by flow cytometry, terminal deoxynucleotidyl transferase dUTP nick end labelling （TUNEL） and electron microscopy. Expression of proliferating cell nuclear antigen （PCNA）, Bcl-2, CD31, caspase-3 and caspase-8 in tumour tissue was determined by immunohistochemistry. The drug concentration that yielded 50% cell inhibition （IC50 value） was 4.74 μg mL-1. In the PC-3 tumour xenograft study, （-）-gossypol （〉 5 mg kg-1） given once a day for 7 days significantly inhibited tumour growth in a dose-dependent manner. Immunohistochemical analysis revealed that （-）-gossypol enhanced caspase-3 and caspase-8 expression and decreased the expression of PCNA, Bcl-2 and CD31 in tumour tissues. It suggested that cell apoptosis and inhibition of angiogenesis might contribute to the anticancer action of （-）-gossypol.

关键词： apoptosis electron microscopy flow cytometry (-)-gossypol immunohistochemistry prostate cancer

Investigating the minimum detectable activity concentration and contributing factors in airborne gamma-ray spectrometry

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Nuclear Science and Techniques 2021年第10期32卷 30-38页

作者： Yi Gu Kun Sun Liang-Quan Ge Yuan-Dong Li qing-xian zhang Xuan Guan Wan-Chang Lai Zhong-xiang Lin Xiao-Zhong Han The College of Nuclear Technology and Automation Engineering Chengdu University of TechnologyChengdu 610059China Key Laboratory of Applied Nuclear Techniques in Geosciences of Sichuan Province Chengdu University of TechnologyChengdu 610059China China Coal Geology Group Co. LtdBeijing 100040China

In this study,the theory of minimum detectable activity concentration(MDAC)for airborne gamma-ray spectrometry(AGS)was derived,and the relationship between the MDAC and the intrinsic effi-ciency of a scintillation counter,volume,and energy res-olution of scintillation crystals,and flight altitude of an aircraft was *** verify this theory,experi-mental devices based on NaI and CeBr 3 scintillation counters were prepared,and the potassium,uranium,and thorium contents in calibration pads obtained via the stripping ratio method and theory were *** MDACs of AGS under different conditions were calculated and analyzed using the proposed theory and the Monte Carlo *** relative errors found via a comparison of the experimental and theoretical results were less than 4%.The theory of MDAC can guide the work of AGS in probing areas with low radioactivity.

关键词： Airborne gamma-ray spectrometry(AGS) Minimum detectable activity concentration(MDAC) Sensitivity

Simulation results of the online tritiated water measurement system

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Nuclear Science and Techniques 2021年第11期32卷 96-104页

作者： Rui-Yang Xu Chun-Hui Dong Xiao-qing Mao qing-xian zhang Hui Gong Kai-yong Liao Zhi-Gang Lu Liang-quan Ge Zhi-Yu Gao Ting-Fang Luo Qi-Chang Huang Chengdu University of Technology Chengdu 610059China Nuclear Power Institute of China Chengdu 610005China

Currently,the liquid scintillation method is widely used to measure the activity of tritiated water in the primary circuit of nuclear power plants,which leads to the continuous production of radioactive waste during *** addition,the real-time activity information of tritiated water cannot be *** solve this problem,herein we present an online tritiated water measurement method based on plastic scintillators that used the optical transport process in the Geant 4 software toolkit to build a model of plastic scintillation detection for tritiated *** simulation,the basic geometric dimensions of the detector were *** this dimension,using one detector to measure for 3 h,when the tritiated water activity was 100 Bq/L,its resolution was 16%(16 Bq/L).In addition,calculations were performed for the presence of other background signals to obtain the minimum detectable concentration.

关键词： Tritiated water Geant 4 Plastic scintillators Measurement system