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A Low-Cost Dual Energy CT System with Sparse Data

Tsinghua Science and Technology 2014年第2期19卷 184-194页

作者： Yuanyuan Liu Jianping Cheng Li Zhang Yuxiang Xing Zhiqiang Chen Peng Zheng Nuclear and radiation Safety Center Ministry of Environmental Protection of China department of Engineering physics Tsinghua University

Dual Energy CT （DECT） has recently gained significant research interest owing to its ability to discriminate materials, and hence is widely applied in the field of nuclear safety and security inspection. With the current technological developments, DECT can be typically realized by using two sets of detectors, one for detecting lower energy X-rays and another for detecting higher energy X-rays. This makes the imaging system expensive, limiting its practical implementation. In 2009, our group performed a preliminary study on a new low-cost system design, using only a complete data set for lower energy level and a sparse data set for the higher energy level. This could significantly reduce the cost of the system, as it contained much smaller number of detector elements. Reconstruction method is the key point of this system. In the present study, we further validated this system and proposed a robust method, involving three main steps：（1） estimation of the missing data iteratively with TV constraints; （2） use the reconstruction from the complete lower energy CT data set to form an initial estimation of the projection data for higher energy level; （3） use ordered views to accelerate the computation. Numerical simulations with different number of detector elements have also been examined. The results obtained in this study demonstrate that 1 ＋ 14% CT data is sufficient enough to provide a rather good reconstruction of both the effective atomic number and electron density distributions of the scanned object, instead of 2 sets CT data.

关键词： X-ray imaging dual energy CT system sparse samples reconstruction material discriminationAR^TV

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Simulation study of the dose and energy responses of FNTD personal neutron dosimetry

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Nuclear Science and Techniques 2019年第2期30卷 29-38页

作者： Yi-Hang Wang Qiang Li Li Chen Yong-Gang Yuan Tai-Ping Peng Institute of Nuclear physics and Chemistry China Academy of Engineering Physics China Institution for radiation protection

The objective of this work was to use the Geant4 toolkit to perform simulation studies on the personal dose response of fluorescent nuclear track detectors(FNTDs).The entire structure of the FNTD response can be designed,and the detector's energy and dose responses can be optimized in a broad energy range(0.01 eV-20 MeV). In general, the detectors used ~6LiF and CH_2 converters that have high energy and high dose response at neutron energies lower than 10 eV and greater than 1 MeV, respectively. The method of least squares was used to optimize the dose response of H*(10) and the energy response corresponding to Rtotal. The values of the optimized response of H*(10) lie between 0.8 and 1.4, corresponding to the energy ranges 0.01 eV-70 keV and 4-14 MeV, respectively. This occupies nearly eight out of the nine orders of the total energy range. Even though the optimized response of Rtotal is constrained between 0.89 and 1.1 in the energy range of 0.01 eV-20 MeV, it is suitable for obtaining the broad neutron spectrum of fluence with good accuracy.

关键词： FNTD Geant4 AI2O3/C,Mg Personal neutron dose

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Uptake of U-and Th-series radionuclides by cereal crops in Upper Egypt

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Nuclear Science and Techniques 2009年第2期20卷 99-105页

作者： SHABAN Harb ROLF Michel Center for radiation protection and Radioecology Hanover University(ZSR) physics department Faculty of ScienceSouth Valley University

The main aim of this study is to determine the activity concentrations of uranium series and thorium series radionuclide in crops cultivated in Upper *** types of cereal crops were collected from local markets and analyzed by γ-ray *** mean activity concentrations of the natural radionuclides 238U,226Ra and 232Th were 0.67,1.27 and 0.56 Bq·kg-1,*** annual effective doses from these radionuclides were estimated for different age groups.

关键词：天然放射性核素谷类作物埃及 U型吸收 226Ra 作物栽培有效剂量

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Measurements of natural radionuclides in soil samples from Upper Egypt

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Nuclear Science and Techniques 2008年第5期19卷 302-307页

作者： Shaban Ramadan Mohamed HARB Khaled SALAHEL DIN Abd Elbaset ABBADY Mohamed Abd Elleh ALI Rolf MICHEL physics department Faculty of ScienceSouth Valley University Center for radiation protection and Radioecology Hanover University (ZSR)

This paper presents the results of natural radioactivity measured for the soil of Qena using gamma-ray spectrometry at ZSR,Hanover University,*** samples of radioactive concentrations of ^(238)U-series (^(234)Th, ^(214)pb,and^(214)Bi),^(232)Th-series (^(228)Ac,^(212)pb,and ^(208)T1) and ^(40)K were *** objectives were set:(1) activity levels by surface soil sampling at 0～30 cm depth,(2) dose rates of gamma radiation,radium equivalent,index hazard, and effective dose,and (3) ambient dose rates.

关键词：土壤环境放射能 γ光谱测定法辐射暴露环境剂量

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A new horizon for neuroscience:terahertz biotechnology in brain research

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Neural Regeneration Research 2025年第2期20卷 309-325页

作者： Zhengping Pu Yu Wu Zhongjie Zhu Hongwei Zhao Donghong Cui Shanghai Key Laboratory of Psychotic Disorders Shanghai Mental Health CenterShanghai Jiao Tong University School of MedicineShanghaiChina department of Psychiatry Kangci Hospital of JiaxingTongxiangZhejiang ProvinceChina Shanghai Synchrotron radiation Facility Shanghai Advanced Research InstituteChinese Academy of SciencesShanghaiChina Key Laboratory of Interfacial physics and Technology Shanghai Institute of Applied PhysicsChinese Academy of ScienceShanghaiChina National Facility for Protein Science in Shanghai Shanghai Advanced Research InstituteChinese Academy of SciencesShanghaiChina

Terahertz biotechnology has been increasingly applied in various biomedical fields and has especially shown great potential for application in brain *** this article,we review the development of terahertz biotechnology and its applications in the field of *** evidence indicates promising prospects for the use of terahertz spectroscopy and terahertz imaging techniques in the diagnosis of amyloid disease,cerebrovascular disease,glioma,psychiatric disease,traumatic brain injury,and myelin *** vitro and animal experiments have also demonstrated the potential therapeutic value of terahertz technology in some neuropsychiatric *** the precise underlying mechanism of the interactions between terahertz electromagnetic waves and the biosystem is not yet fully understood,the research progress in this field shows great potential for biomedical noninvasive diagnostic and therapeutic ***,the biosafety of terahertz radiation requires further exploration regarding its two-sided efficacy in practical *** review demonstrates that terahertz biotechnology has the potential to be a promising method in the field of neuropsychiatry based on its unique advantages.

关键词： biological effect brain neuron neuropsychiatry neuroscience non-thermal effect terahertz imaging terahertz radiation terahertz spectroscopy terahertz technology

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Gamma-ray measurements of natural radioactivity in sedimentary rocks from Egypt

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Nuclear Science and Techniques 2006年第2期17卷 123-128页

作者： A.M.EL-ARABI Adel G.E.ABBADY A.S.HUSSEIN physics department Faculty of Science South Valley University Qena Egypt radiation protection department Nuclear Power Plants Authority Egypt

The aim of this study was to measure concentrations and distributions of natural radionuclides occurring in rocks. The activity concentrations (Bq·kg-1) of the naturally occurring radionuclides 226Ra, 232Th, and 40K in sedi- mentary rock samples from Eastern Desert (Um El-Huetat), Nile Valley (Gebel Owina) and from southwest Sinai (Wadi Ghweiba) were measured using a high-purity germanium detector. The samples under investigation (clay, shale and sandstone) were used as raw materials in the construction industry (bricks, ceramics, cement, fillers, etc.). Though the sediments of Egypt have already been investigated in the geological and mineralogical aspects, it is necessary to investigate the natural radioactivity in order to complete their classification. The average concentration values of 226Ra, 232Th, 40K in the surveyed samples were 47 ± 7 , 21± 5, 393±19 ***-1 (clay); 23 ± 5, 30 ± 6, 563 ± 24 ***-1 (shale); and 17 ± 4, 14 ± 4, 299 ± 17 ***-1 (sandstone), respectively. All sediment samples have radium equivalent activities ranging from 55 to 115 Bq·kg-1, lower than the limit set in the OECD Report (370 Bq·kg-1). The overall mean outdoor terrestrial gamma dose rates fluctuate from 28 to 55 nGy·h-1. The external gamma radiation dose due to natural radionuclides present in the samples have been computed and compared with the global averages. In terms of the radiation safety, the natural radioactivity of the sediment in Egypt is below the recommended limits of the gamma dose rate. Therefore, they can be used for all kinds of public buildings.

关键词：天然放射性核素页岩沙岩埃及

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A new method for position-sensitive measurement of beta surface contamination

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Nuclear Science and Techniques 2017年第2期28卷 49-56页

作者： Yan-Tao Qu Hui Wang Yang Liu Ling Chen Jie Hou Zhe Liu Ji-Zeng Ma department of radiation protection China Institute of Atomic Energy Beijing 102413 China Nuclear and radiation Safety Center Ministry of Environment Protection Beijing 100082 China Occupational radiation protection Unit Radiation Safety and Monitoring Section NSRW IAEA PO Box 1001400 Vienna Austria

In this paper, we propose a new method for position-sensitive measurement of beta surface contamination. With a position-sensitive detector of enlarged sensitive detection area, accurate information of the contamination distribution can be obtained. The positionsensitive detection is based on a large-area plastic scintillator and the wavelength shifting(WLS) fibers and adopts the ‘‘light center of gravity'' method. Optical transmission of the detector is simulated with a preliminary detector model, and feasibility of the detector design and measurement method is evaluated using an experiment *** simulation and experiment results at different beta-ray incident points on the scintillator surface show that there is a polynomial relationship between the average amplitude ratio of the output pulses from the two parallel WLS fibers in the same fiber layer and the relative distance from the incident point to the WLS fiber.

关键词： Beta surface contamination Position-sensitive measurement Wavelength shifting fibers Plastic scintillator

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Reliability analysis of the gasification process of nuclear fuel manufacturing facilities based on the GO methodology

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Nuclear Science and Techniques 2019年第10期30卷 85-94页

作者： Yan Wang Zhi-Jie Gu Bing Lian Jie Yang Yang-Jun Zhao department of Nuclear Environmental Sciences China Institute for Radiation Protection

Uranium hexafluoride(UF6)leakage accidents represent one of the most serious classes of accidents in the gasification process in nuclear fuel manufacturing *** UF6 leakage accidents include various fault conditions,such as pipeline and valve breakages or ruptures and pipeline *** establishing goal-oriented(GO)operators that can represent multi-fault states,this study estimates the probabilities of various fault states corresponding to UF6 leakage accidents in the gasification process using the GO methodology and analyzes the system *** article expands the scope of the GO methodology and provides technical support for reliability analysis using the GO methodology in multi-fault systems.

关键词： GO methodology Operator Multi-fault state Reliability analysis UF6 leakage

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Optimization of moderator assembly for neutron flux measurement:experimental and theoretical approaches

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Nuclear Science and Techniques 2017年第5期28卷 7-12页

作者： Abdul Waheed Nawab Ali Muzahir A.Baloch Aziz A.Qureshi Eid A.Munem Muhammad Usman Rajput Tauseef Jamal Wazir Muhammad radiation physics Laboratory Physics DepartmentCOMSATS Institute of Information Technology(CIIT)

A moderator of paraffin wax assembly has been demonstrated where its thickness can be optimized to thermalize fast neutrons. The assembly is used for measuring fast neutron flux of a neutron probe at different neutron energies, using BF03(U10and 200) and3He(U0.500)neutron detectors. The paraffin wax thickness was optimized at 6 cm for the neutron probe which contains an Am–Be neutron source. The experimental data are compared with Monte Carlo simulation results using MCNP5 version 1.4. Neutron flux comparison and neutron activation techniques are used for measuring neutron flux of the neutron probe to validate the optimum paraffin moderator thickness in the assembly. The neutron fluxes are measured at(1.17 ± 0.09) 9 105 and(1.19 ± 0.1) 9 105n/s, being in agreement with the simulated values. The moderator assembly can easily be utilized for essential requirements of neutron flux measurements.

关键词： Am–Be and 252Cf neutron sources BF3&3He detectors Paraffin wax Neutron flux Monte Carlo simulation

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GSN antibody pretreatment aggravates radiation-induced lung injury in mice

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Nuclear Science and Techniques 2014年第2期25卷 26-31页

作者：王洁袁小鹏顾成黄建峰俞家华刘芬菊 department of Radiobiology School of Radiation Medicine and ProtectionMedical College of Soochow University School for Radiological and Interdisciplinary Sciences Soochow University

radiation-induced lung injury is one of the main dose limiting factors for thoracic radiation ***(GSN) is a widespread,multifunctional regulator of cellular structure and *** this work,the roles of GSN in radiation-induced lung injury in Balb/c mice were *** GSN levels in plasma reduced progressively in 72 hours after irradiation,and then increased *** contents in the bronchoalveolar lavage(BAL) fluid increased after thoracic irradiation,whereas mRNA levels of GSN in the lung tissue decreased significantly within 24 hours after irradiation and then increased *** were intravenously injected with 50 ug GSN antibody 0.5 hour before 20 Gy of thoracic *** antibody pretreatment increased lung inflammation,protein concentration in the BAL fluid and leukocytes infiltration in the irradiated *** activities of superoxidase dismutase(SOD) in the plasma and the BAL fluid in irradiated mice injected with GSN antibody were less than that of control groups,whereas the levels of malondialdehyde(MDA)*** results suggest that pretreatment of GSN antibody may aggravate radiation-induced pneumonitis.

关键词： GSN 肺损伤放射性预处理小鼠抗体 mRNA水平超氧化物歧化酶

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