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Cross section measurement for the^(232)Th(n,f)reaction in the 4.50−5.40 MeV region using a time projection chamber

Chinese Physics C 2024年第10期48卷 157-167页

作者： Haofan Bai Han Yi Yankun Sun Yiwei Hu Jie Liu Zepeng Wu Cong Xia Wenkai Ren wentian cao Tieshuan Fan Guohui Zhang Ruirui Fan Yang Li Wei Jiang Yonghao Chen You Lv Changjun Ning Weihua Jia Zhiyong Zhang Haolei Chen Zhen Chen Maoyuan Zhao Changqing Feng Shubin Liu State Key Laboratory of Nuclear Physics and Technology Institute of Heavy Ion PhysicsPeking UniversityBeijing 100871China Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China Spallation Neutron Source Science Center Dongguan 523803China National Key Laboratory of Intense Pulsed Radiation Simulation and Effect Northwest Institute of Nuclear TechnologyXi'an 710024China Department of Nuclear Science and Technology School of Energy and Power EngineeringXi’an Jiaotong UniversityXi’an 710049China State Key Laboratory of Particle Detection and Electronics University of Science and Technology of ChinaHefei 230026China Department of Modern Physics University of Science and Technology of ChinaHefei 230026China

Accurate cross sections of neutron induced fission reactions are required in the design of advanced nuclear systems and the development of fission *** projection chambers(TPCs),with their track reconstruction and particle identification capabilities,are considered the best detectors for high-precision fission cross section *** TPC developed by the back-streaming white neutron source(Back-n)team of the China Spallation Neutron Source(CSNS)was used as the fission fragment detector in *** this study,the cross sections of the ^(232)Th(n,f)reaction at five neutron energies in the 4.50−5.40 MeV region were *** fission fragments and α particles were well identified using our TPC,which led to a higher detection efficiency of the fission fragments and smaller uncertainty of the measured cross *** is the first measurement of the ^(232)Th(n,f)reaction using a TPC for the detection of fission *** uncertainties less than 5%,our cross sections are consistent with the data in different evaluation libraries,including JENDL-4.0,ROSFOND-2010,CENDL-3.2,ENDF/B-VⅢ.0,and BROND-3.1,whose uncertainties can be reduced after future improvement of the measurement.

关键词： ^(232)Th(n,f)fission cross section time projection chamber(TPC) ^(232)Th

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Exploration and Research on Employment Guidance System in Universities from the Perspective of Artificial Intelligence

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Open Journal of Applied Sciences 2023年第6期13卷 934-940页

作者： wentian cao Xueer Ye Xiaoying Chen Student Affairs Office Wenzhou Medical University Wenzhou China

In the context of the era of continuous development of artificial intelligence, the labor value of university students is impacted by technological substitution. Simultaneously, university students are also required to constantly update their skills. All of the above will be the challenge of university students’ employment prospects. However, artificial intelligence will also bring new opportunities, which will stimulate the innovation ability of university students and bring new directions for employment. In order to better cope with the possible impact of artificial intelligence, universities should incorporate employment guidance services into the “three-wide education” system. To achieve this, universities need to take the following measures: developing the dynamic monitoring system of university employment based on big data, constructing the employment guidance curriculum system of university students throughout the whole process, updating the mode of diversified employment guidance service as well as establishing a team of employment guidance teachers keeping pace with the times. These measures aim to better adapt to the job market demands in the context of artificial intelligence, guide students to actively respond to the possible impact of artificial intelligence technology, cultivate their core competencies and qualities that are less likely to be replaced by artificial intelligence, and promote the high-quality employment of university students.

关键词： Employment Guidance Artificial Intelligence High Quality Employment University Students

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Preparation and Properties of GaN Micro-Ribbons on Ga-Diffused Si （111） Substrates

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稀有金属材料与工程 2005年第7期34卷 1162-1165页

作者： XueChengshan SunZhencui WeiQinqin caowentian ZhuangHuizhao ShandongNormalUniversity Jinan250014China

Hexagonal GaN micro-ribbons were synthesized through nitriding Ga2O3 films under flowing ammonia. Ga2O3 films were deposited on the Ga-diffused Si (111) substrates by radio frequency (r.f.) magnetron sputtering. X-ray diffraction (XRD), scanning electron microscopy (SEM), selected area electron diffraction (SAED); X-ray photo electronic spectrometer (XPS) and photoluminescence (PL) spectroscopy were used to characterize the structure, surface morphology, composition and optical property of the synthesized samples. SEM images show that GaN micro-ribbons with 100-300rim in diameter are randomly distributed on the uniform films. XRD, XPS and SAED analysis suggest the micro-ribbons are polycrystalline GaN with hexagonal structure and preferentially grow in the [001] direction. The PL spectrum has a remarkable blue shift compared with the reported values of bulk GaN, which might be ascribed to quantum confinement effects.

关键词： Ga2O3 films GaN micro-ribbons radio frequency (r.f.) magnetron sputtering

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EVALUATION OF NEUTRON NUCLEAR DATA OF NATURAL CALCIUM FOR CENDL-2

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中国核科技报告 1989年第S2期 41-48页

作者： Tang Guoyou Bao Shanglian Shi Zhaomin cao wentian(INSTITUTE OF HEAVY ION PHYSICS PEKING UNIVERSITY)

Neutron nuclear data of natural calcium for CENDL-2 were evaluated in the energyregion from 10eV to 20 *** quantities are the toal,non-elastic scattering,elastic and inelastic scattering,radiation capture,(n,p),(n,t),(n,2n,)(n,α)reactioncross sections,some angular distributions and energy *** of the data were calcu-lated with the program AUJP based on optical model and the program MUP2 based onHauser-Feshbach model and pre-equilibrium evaporation model.

关键词： EVALUATION OF NEUTRON NUCLEAR DATA OF NATURAL CALCIUM FOR CENDL-2 data ENDF

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EVALUATION OF NEUTRON NUCLEAR DATA OF NATURAL CALCIUM FOR CENDL-2

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中国核科技报告 1992年第S2期 31-39页

作者： Tang Guoyou Bao Shanglian Shi Zhaomin cao wentian (INSTITUTE OF HEAVY ION PHYSICS, PEKING UNIVERSITY)

Neutron nuclear data of natural calcium for CENDL-2 has been evalu-ated in the energy region from 10eV to 20 *** quantities are thetotal,nonelastic scattering,elastic and inelastic scattering,radiation capture,(n,p)(n,t),(n,2n),(n,α)reaction cross sections and the angular distributions ofelastic and inelastic cross *** of the data were calculated with theprogram AUJP based on optical model and the program MUP2 based on Hauser-Feshbach model and pre-equilibrium evaporation model.

关键词： EVALUATION OF NEUTRON NUCLEAR DATA OF NATURAL CALCIUM FOR CENDL-2 data NP

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草地承包中、前期放牧行为及相关生态补偿对策建模研究

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北京大学学报（自然科学版） 2009年第3期45卷 528-532页

作者：宋波辛永亮曹文田北京科技大学土木与环境工程学院环境工程系北京100083 北京大学物理学院北京100871

分析牧民的放牧行为并予以指导,有助于缓解或避免由于过度放牧导致的草地退化。利用牧草生长-消费模型,引入贴现影响,分析了牧民接手草地后的承包前期和中期放牧行为。结果显示,在承包前期,无论草地产权制度多么完善,当初始牧草生物量... 详细信息

分析牧民的放牧行为并予以指导,有助于缓解或避免由于过度放牧导致的草地退化。利用牧草生长-消费模型,引入贴现影响,分析了牧民接手草地后的承包前期和中期放牧行为。结果显示,在承包前期,无论草地产权制度多么完善,当初始牧草生物量较高时,牧民总会采用最大放牧强度,使牧草生物量迅速下降至经济最佳牧草生物量水平。在承包中期,牧民会降低放牧强度,使牧草生物量维持在经济最佳牧草生物量水平。承包中期的放牧强度与贴现率正相关,此时的牧草生物量与贴现率负相关。为保障牧草生物量不低于一定的阈值,可以采取向牧民发放生态补偿金的经济措施,以促使牧民降低放牧强度。补偿金额是补偿系数与实际牧草生物量的乘积,补偿系数与贴现率正相关,与牧草生物量阈值负相关。

关键词：生长-消费模型承包前期放牧行为承包中期放牧行为经济最佳牧草生物量生态补偿草地管理

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EVALUATION OF NEUTRON NUCLEAR DATA OF 237Np FOR CENDL-2

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中国核科技报告 1991年第S2期 290-300页

作者： Tang Guoyou Fan Jihong cao wentian Bao Shanglian (INST. OF HEAVY ION PHYSICS, PEKING UNIVERSITY ) Cai Chonghai ( PHYSICS DEPARTMENT, NANKAI UNIVERSITY )

The measured data of（n,f）,（n,γ）reaction for237Np have been evaluated inthe energy region from 30 keV to 20 *** the data of237Np for other reac-tion channels are theoretically *** recommended experimental dataand the theortically calculated data are adjusted and make σtot=σel+σnonAll the data in the energy range 10-5eV to 20 MeV are recommended as the da-ta file of237Np for CENDL-2.

关键词： ENDF data EVALUATION OF NEUTRON NUCLEAR DATA OF Np FOR CENDL-2 NSE

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基于Monte Carlo模拟的系统矩阵解析算法

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仪器仪表学报 2009年第9期30卷 1789-1794页

作者：凌松云曹文田李军蔡白银包尚联北京大学医学物理和工程北京市重点实验室北京100871

系统矩阵是单光子发射计算机断层成像系统(SPECT)中迭代重建算法的关键因素。蒙特卡洛(MC)模拟是计算系统矩阵最准确、最常用的方法,但是标准的MC算法最大的缺点就是耗时太长。为此,提出一种新的解析算法:利用MC模拟的投影数据,拟合准... 详细信息

系统矩阵是单光子发射计算机断层成像系统(SPECT)中迭代重建算法的关键因素。蒙特卡洛(MC)模拟是计算系统矩阵最准确、最常用的方法,但是标准的MC算法最大的缺点就是耗时太长。为此,提出一种新的解析算法:利用MC模拟的投影数据,拟合准直器的点扩散函数,并以此作为计算系统矩阵的解析表达式。该新算法既缩短了计算耗时又包含了MC投影信息,使得解析计算的系统矩阵与MC模拟的结果相当。因此,该方法可用于修正准直器张角效应对系统矩阵计算的影响。本文采用解析计算得到的系统矩阵,重建了均匀泛源和Jaszczak模型的MC投影图像,重建图像能真实的反映原始图像。

关键词：蒙特卡洛系统矩阵准直器张角效应点扩散函数

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Zeros of Complete Symmetric Polynomials over Finite Fields

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Journal of Systems Science & Complexity 2024年第4期37卷 1772-1788页

作者： cao Wei School of Mathematics and Statistics Minnan Normal UniversityZhangzhou 363000China

Wan and Zhang(2021) obtained a nontrivial lower bound for the number of zeros of complete symmetric polynomials over finite fields,and proposed a problem whether their bound can be *** this paper,the author improves Wan-Zhang's bound from three *** proposed results are based on the estimates related to the number of certain permutations and the value sets of non-permutation polynomials associated to the complete symmetric *** the author believes that there are still possibilities to improve the bounds and hence Wan-Zhang's bound.

关键词： Complete symmetric polynomial finite field permutation polynomial value set

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Pt nanodendrites with a PtIr alloy surface structure exhibit excellent stability toward acidic hydrogen evolution reaction

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Nano Research 2024年第6期17卷 4844-4849页

作者： Chang Liu Zongnan Wei Minna cao Rong cao State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China University of Chinese Academy of Sciences Beijing 100049China Fujian Science and Technology Innovation Laboratory for Optoelectronic Information of China Fuzhou 350108China

The development of effective and stable electrocatalysts for the hydrogen evolution reaction(HER)in acidic electrolytes is a significant *** this work,homogeneous Pt nanodendrites(Pt NDs)with a PtIr shell were successfully synthesized by a two-step wet chemical *** open three-dimensional(3D)dendritic structure exhibited exceptional electrocatalytic characteristics,exposing as many active sites as ***,by alloying Ir with Pt on the surface,catalytic activity was greatly enhanced while ensuring extremely high *** surface-enriched platinum nanodendritic catalysts(Pt@PtIr NDs)outperformed the control samples and the commercial *** acidic HER test,Pt@PtIr NDs had a lower overpotential(22 mV)than Pt NDs(26 mV)and commercial Pt/C(31 mV)at 10 mA/cm^(2),and the activity of Pt@PtIr NDs remained consistent even after undergoing a continuous durability test for at least 168 h,which was much superior to the performance of commercial Pt/C(10 h)under identical test *** study revealed that the application of 3D Pt dendritic metal alloys may offer a chance for the development of enhanced electrocatalysts in acidic HER.

关键词： Pt nanodendrites iridium high stability hydrogen evolution reaction alloy

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