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Electron irradiation effects on DC electrical performances of SiGe HBT in a comparison with Si BJT

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Rare Metals 2004年第4期23卷 330-339页

作者： mengxiangti ZHANGXimin WANGJilin HUANGWentiao CHENPeiyi KLAHongyong instituteofnuclearandNewenergytechnology TsinghuaUniversityBeijing100084China instituteofMicroelectronics TsinghuaUniversityBeijing100084China

The DC characteristics of SiGe HBT irradiated at different electron dose havebeen studied in a comparison with those of Si B JT. Generally, I_b and I_b - I_(b0) increase, I_c,I_c -I_(c0) and its +/- transition V_(be) as well as DC current gain ft decreases with increasingdose; increase of I_b -I_(b0) with increasing dose for Si BIT is much larger than that for SiGe HBT;beta increases with V_(be) or I_b, but decreases at I_b < 0.25 mA with I_b, and congregates athigher dose; and a damage factor d(beta) is much less at the same dose for SiGe HBT than for Si *** HBT has much better anti-radiation performance than Si BJT. Some anomalous phenomena forincrease of I_c, I_c -I_(c0), I_b -I_(b0) and beta at low dose have been found. Some electron trapshave been measured. The mechanism of changes of characteristics is discussed.

关键词： semiconductor technology SiGe HBT electron irradiation Si BJT DCelectrical performance

INFRARED ABSORPTION BANDS OF Si-H CENTERS IN γ-RAY IRRADIATED FZSi GROWN IN HYDROGEN ATMOSPHERE AND THEIR IDENTIFICATION

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Science in china,Ser.A 1987年第2期30卷 176-185页

作者：杜永昌张玉峰孟祥提沈宏扬 Department of Physics Peking university institute of nuclear energy technology Qinghua university institute of Atomic energy Academia Sinica beijing

Gamma-ray irradiated and neutron irradiated silicon have been stualea using the rourler transiorm inftared spectroscopy and deep-level transient spectroscopy. In γ-ray irradiated silicon the production rate of divacancy is very low, which can be used to identify radiation point defects. Only three new Si-H stretching vibration bands of 1832, 2054 and 1980 cm-1 are produced in γ-ray irradiated FZ （H）Si, fewer than that in neutron irradiated FZ（H）Si. In this paper the models of the three bands are discussed and their optical absorption sections are estimated.

关键词： RAY IRRADIATED FZSi GROWN IN HYDROGEN ATMOSPHERE AND THEIR IDENTIFICATION INFRARED ABSORPTION BANDS OF Si-H CENTERS IN Si

Vacancy-Type Defects in Neutron-Irradiated Silicon

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Chinese Physics Letters 1993年第10期10卷 605-608页

作者： meng xiangti institute of nuclear energy Tcchnologyf tsinghua UniversityBeijing 100084

Position annihilation measurements show that the radiation defects and secondary defects in neutron-transmutation-doped(NTD)Si irradiated by two neutron doses can he removed at 600-650℃。The concentration and annealing behavior of V-type and Vo defects are related to the neutron doses.V_(4 )appears at 150℃ and 450℃-550℃ in NTD Si irradiated by higher neutron dose.

关键词： irradiated removed annihilation

CHARACTERS OF NTD FZ(H_(2)) Si KEPT AT ROOM TEMPERATURE FOR THREE YEARS

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Chinese Physics Letters 1989年第2期6卷 80-83页

作者： meng xiangti institute of nuclear energy technology Tsinghua UniversityBeijing

It has been found that the hydrogen-dtfect shallow donors do not appear,and some strong neutron radiation-induced Si-H IR bands,such as 1882 and 2054cm^(-1) disappear;but the strength of some others,e.g.1979 and 2065cm^(-1) increases greatly for NTD FZ(H_(2))Si kept at room temperature for 3 *** changes indicate that at room temperature simple point defects diffuse and interact,and hydrogen atoms trap the vacancy and vacancy cluster *** gives important information in the discussion of the micro-structures of the above Si-H IR bands.

关键词： vacancy bands cluster

Milestone progress of the HEPS booster commissioning

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nuclear Science and Techniques 2024年第1期35卷 170-177页

作者： Yue-Mei Peng Jian-She Cao Jin-Hui Chen Hai-Yi Dong Ping He Yi Jiao Ling kang Wen kang Jian Li Jing-Yi Li Guo-Ping Lin Fang Liu Feng-Li Long Cai meng Xin Qi Hua-Min Qu Yan-Feng Sui Sheng Wang Gang Xu Qiang Ye Jing Zhang Pei Zhang Wei-Min Pan Key Laboratory of Particle Acceleration Physics and technology Institute of High Energy PhysicsChinese Academy of Sciences19B Yuquan RoadShijingshan DistrictBeijing 100049China university of the Chinese Academy of Sciences 19A Yuquan RoadShijingshan DistrictBeijing 100049China

The high-energy photon source(HEPS)is the first fourth-generation synchrotron light source facility in *** HEPS injector consists of a linear accelerator(Linac)and a full energy *** booster captures the electron beam from the Linac and increases its energy to the value required for the storage *** full-energy beam could be injected to the storage ring directly or after“high-energy accumulation.”On November 17,2023,the key booster parameters successfully reached their corresponding target *** milestone results were achieved based on numerous contributions,including nearly a decade of physical design,years of equipment development and installation,and months of beam *** measured at the extraction energy of 6 GeV,the averaged beam current and emittance reached 8.57 mA with 5 bunches and 30.37 nm rad with a single-bunch charge of 5.58 nC,compared with the corresponding target values of 6.6 mA and 35 nm rad,*** paper presents the physical design,equipment development,installation,and commissioning process of the HEPS booster.

关键词： High energy photon source Booster Beam commissioning

Normalized glandular dose coefficients for digital breast tomosynthesis using detailed Chinese breast models

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nuclear Science and Techniques 2024年第5期35卷 42-59页

作者： Jia-Hao Wang Rui Qiu An-kang Hu Ye-Qi Liu Zhen Wu Hui Zhang Jun-Li Li Department of Engineering Physics Tsinghua UniversityBeijing 100084China Key Laboratory of Particle and Radiation Imaging Ministry of EducationTsinghua UniversityBeijing 100084China Joint institute of tsinghua university Nuctech Company Limited BeijingBeijing 100084China

The rise in breast cancer diagnoses among Chinese women has necessitated the use of X-ray breast screening,which carries a radiation *** study aimed to provide a dosimetry protocol for the Chinese female population to replace the traditional standard that utilizes simplified breast models,for the accurate estimation of the mean glandular dose of a patient undergoing digital breast tomosynthesis(DBT).The first set of detailed Chinese female breast models and representative breast parameters was *** backscatter radiation and computational efficiency,we improved the combination of these models and the Chinese reference adult female whole-body voxel *** acquisition for four commercial DBT systems that are widely employed in china was simulated using the Monte Carlo method to obtain the normalized glandular dose coefficients of DBT(D_(gN)^(DBT))and the glandular depth dose(D_(g)^(dep)(z))for different breast characteristics and X-ray *** calculated a series of D_(gN)^(DBT) values for breasts with different percentage mass glandularities(5%,25%,50%,75%,and 100%)and compressed breast thicknesses(2,3,4,5,6,and 7 cm)at various tube potentials(25,28,30,32,35,and 49 kV)and target/filter combinations(W/Rh,W/Al,Mo/Mo,Rh/Rh,and Rh/Ag).The parameter dependence of the breast characteristics and beam conditions on D_(gN)^(DBT) in detailed breast models was *** D_(gN)^(DBT) results were 14.6-51.0%lower than those of the traditional dosimetry standard in *** difference in D_(gN)^(DBT) was mainly due to a decrease in the depth of the main energy deposition area caused by the glandular distribution along the depth *** results obtained in this study may be used to improve breast dosimetry in china and provide more detailed information on risk assessment during DBT.

关键词： Digital breast tomosynthesis Normalized glandular dose coefficients Detailed breast model Monte Carlo simulation

Study on the optimal incident proton energy of ^(7)Li(p,n)^(7)Be neutron source for boron neutron capture therapy

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nuclear Science and Techniques 2024年第3期35卷 170-180页

作者： Yi-Nan Zhu Zuo-kang Lin Hai-Yan Yu Ye Dai Zhi-Min Dai Xiao-Han Yu Shanghai institute of Applied Physics Chinese Academy of SciencesShanghai 201800China university of Chinese Academy of Science Beijing 100049China

Boron neutron capture therapy(BNCT)is recognized as a precise binary targeted radiotherapy technique that effectively eliminates tumors through the^(10)B(n,α)^(7)Li nuclear *** various neutron sources,accelerator-based sources have emerged as particularly promising for BNCT ***^(7)Li(p,n)^(7)Be reaction is highly regarded as a potential neutron source for BNCT,owing to its low threshold energy for the reaction,significant neutron yield,appropriate average neutron energy,and additional *** study utilized Monte Carlo simulations to model the physical interactions within a lithium target subjected to proton bombardment,including neutron moderation by an MgF_(2)moderator and subsequent BNCT dose analysis using a Snyder head *** study focused on calculating the yields of epithermal neutrons for various incident proton energies,finding an optimal energy at 2.7 ***,the Snyder head phantom was employed in dose simulations to validate the effectiveness of this specific incident energy when utilizing a^(7)Li(p,n)^(7)Be neutron source for BNCT purposes.

关键词： Boron neutron capture therapy ^(7)Li(p,n)7Be neutron source Incident proton energy Monte Carlo simulation

Quantifying the contribution of activity patterns to PM_(2.5)exposure inequity between urban and rural residents by a novel method

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Building Simulation 2024年第8期17卷 1323-1333页

作者： Wei Du Zhanpeng Cui Jinze Wang Yuqiong Wang Yungui Li Xiaoan Li Yan Zhou Tao Jiang kang Mao Xianbiao Lin Jianwu Shi Dengzhou Gao Yiming Qin Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control Faculty of Environmental Science&EngineeringKunming University of Science&TechnologyKunming 650500China Laboratory of Earth Surface Processes College of Urban and Environmental SciencesPeking UniversityBeijing 100871China Department of Environmental Engineering Southwest University of Science and TechnologyMianyang 621010China NHC Key Laboratory of nuclear technology Medical Transformation Mianyang Central HospitalSchool of MedicineUniversity of Electronic Science and Technology of ChinaMianyang 621000China State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China Key Laboratory of Marine Chemistry Theory and technology Ministry of EducationOcean University of ChinaQingdao266100China Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education School of Geographical SciencesFujian NormalUniversityFuzhou350117China School of energy and Environment City University of Hong KongHong KongChina

PM_(2.5)pollution variations in different microenvironments would result in PM_(2.5)exposure inequity between rural and urban *** this study,the real-time PM_(2.5)exposure of urban and rural residents in china was examined based on portable PM_(2.5)sensors together with activity patterns derived from questionnaire surveys,with a focus on students and senior citizens who are sensitive to air *** results showed that PM_(2.5)exposure varied significantly among different resident groups,with higher PM_(2.5)exposure of rural residents than those of urban ***_(2.5)exposure peaks mostly occurred during(Accompanied)cooking activities owing to strong *** and resting were the main activities that affected PM_(2.5)exposures of different resident groups,accounting for 60.7%-94.5%of total daily ***,the long duration of sleeping makes it the predominant activity contributing to PM 25 exposure *** is necessary to obtain point-to-point respiratory volume(respiratory rate)data when measuring real-time PM_(2.5)exposure data and incorporate respiratory volume(respiratory rate)into the analysis of PM_(2.5)*** the first time,this study quantified the PM_(2.5)exposure inequality based on a novel method and can provide useful information for further studies on the exposure inequity.

关键词： PM_(2.5)exposure environmental inequity activity pattern urban and rural difference

Germylene-Fe complexes caused by heterometallic coupling and investigation into the 3d-4p bonding

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Chinese Chemical Letters 2024年第3期35卷 304-307页

作者： Yingying Qin Yongmei kang Lei Zhang Jianping Sun Zhijing Zhang Jialei Xu Fanlong Zeng Anyang Li Wenyuan Wang Weiqun Shi Key Laboratory of Synthetic and Natural Functional Molecule of Ministry of Education College of Chemistry and Materials ScienceNorthwest UniversityXi'an 710127China Laboratory of nuclear energy Chemistry Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China Shaanxi Coal and Chemical Industry Xi'an 710054China

The interpretation of heterometallic bonding nature is a basic work of inorganic *** means of intermetallic substitution of germylene anions with iron halide complexes CpFe(CO)_(2)I andβ-diketiminato Fe^Ⅱchloride,the ferrogermylene complexes 3a,3b and 4a were synthesized and structurally *** structural and IR characterizations show the presence of the Ge←Feπbackbonding in molecules 3a,3b and *** computational works on frontier molecular orbitals and their comparison of energy states confirmed thatσdonation andπbackbonding are both weak in these molecules,despite three complexes have longer Ge-Fe bonds,whose strength decreases slightly with the degressive electron density around Fe environment in a sequence from 3a,3b to 4a.

关键词： Metallic bonding Germylene Iron Crystal structure σbond πbackbond