检索结果-南通市图书馆

同方期刊数据库

Measurement of the ^(232)Th(n,f)cross section in the 1-200 MeV range at the CSNS Back-n

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2023年第8期34卷 142-153页

作者： Zhi-Zhou Ren Yi-Wei Yang Yong-Hao Chen Rong liu Bang-jiao Ye jie Wen Hai-Rui Guo Zi-jie Han Qi-Ping Chen Zhong-Wei Wen Wei-li Sun Han Yi Xing-Yan liu Tao Ye jiang-Bo Bai Qi An jie Bao Yu Bao Ping Cao Hao-lei Chen Zhen Chen Zeng-Qi Cui Rui-Rui Fan Chang-Qing feng Ke-Qing Gao Xiao-Long Gao Min-Hao Gu Chang-Cai Han Guo-Zhu He Yong-Cheng He Yang Hong Yi-Wei Hu Han-Xiong Huang Xi-Ru Huang Hao-Yu jiang Wei jiang Zhi-jie jiang Han-Tao jing ling Kang Bo li Chao li jia-Wen li Qiang li Xiao li Yang li jie liu Shu-Bin liu Ze Long Guang-Yuan Luan Chang-Jun Ning Meng-Chen Niu Bin-Bin Qi jie Ren Xi-Chao Ruan Zhao-Hui Song Kang Sun Zhi-jia Sun Zhi-Xin Tan jing-Yu Tang Xin-Yi Tang Bin-Bin Tian li-jiao Wang Peng-Cheng Wang Zhao-Hui Wang Xiao-Guang Wu Xuan Wu li-Kun Xie Xiao-yun Yang li Yu Tao Yu Yong-ji Yu Guo-Hui zhang lin-Hao zhang Qi-Wei zhang Xian-Peng zhang Yu-liang zhang Zhi-Yong zhang Lu-Ping Zhou Zhi-Hao Zhou Ke-Jun Zhu Department of Modern Physics University of Science and Technology of ChinaHefei 230026China Institute of Nuclear Physics and Chemistry China Academy of Engineering PhysicsMianyang 621900China Institute of High Energy Physics Chinese Academy of Sciences(CAS)Beijing 100049China Spallation Neutron Source Science Center Dongguan 523803China Institute of Applied Physics and Computational Mathematics Beijing 100088China State Key Laboratory of Particle Detection and Electronics University of Science and Technology of ChinaHefei 230027China Key Laboratory of Nuclear Data China Institute of Atomic EnergyBeijing 102413China School of Nuclear Science and Technology University of Science and Technology of ChinaHefei 230027China State Key Laboratory of Nuclear Physics and Technology School of PhysicsPeking UniversityBeijing 100871China State Key Laboratory of Particle Detection and Electronics Institute of High Energy PhysicsChinese Academy of SciencesBeijingChina Northwest Institute of Nuclear Technology Xi’an 710024China University of Chinese Academy of Sciences Beijing 100049China Department of Engineering and Applied Physics University of Science and Technology of ChinaHefei 230026China

The ^(232)Th(n,f)cross section is very important in basic nuclear physics and applications based on the Th/U fuel *** the time-of-flight method and a multi-cell fast-fission ionization chamber,a novel measurement of the^(232)Th(n,f)cross sec-tion relative to^(235)U in the 1–200 MeV range was performed at the China Spallation Neutron Source Back-n white neutron source(Back-n).The fission event-neutron energy spectra of^(232)Th and^(235)U fission cells were measured in the single-bunch *** 232Th/235U fission cross-sectional ratios were obtained,and the measurement uncertainties were 2.5–3.7%for energies in the 2–20 MeV range and 3.6–6.2%for energies in the 20–200 MeV ***^(232)Th(n,f)cross section was obtained by introducing the standard cross section of^(235)U(n,f).The results were compared with those of previous theoreti-cal calculations,measurements,and *** measured 232Th fission cross section agreed with the main evaluation results in terms of the experimental uncertainty,and 232Th fission resonances were observed in the 1–3 MeV *** present results provide^(232)Th(n,f)cross-sectional data for the evaluation and design of Th/U cycle nuclear systems.

关键词： 232Th(n f)cross section Fast-fission ionization chamber Back-n white neutron source

在线全文

学校读者我要写书评

暂无评论

全息谱转频椭圆特征参数的改进及应用

兰州理工大学学报 2014年第2期40卷 35-40页

作者：瞿雷陈余平张建峰金颖屈运动西安陕鼓动力股份有限公司陕西西安710075

全息谱鉴别转频故障的关键在于充分利用转频椭圆提供的特征信息.针对原偏心率指标对椭圆扁平程度变化敏感性较差的缺陷,提出改进的偏心率指标.通过构造两测点转频处的幅值比、相位差两个参数,讨论决定转频椭圆偏心率、倾斜方向的主要因... 详细信息

全息谱鉴别转频故障的关键在于充分利用转频椭圆提供的特征信息.针对原偏心率指标对椭圆扁平程度变化敏感性较差的缺陷,提出改进的偏心率指标.通过构造两测点转频处的幅值比、相位差两个参数,讨论决定转频椭圆偏心率、倾斜方向的主要因素,定量分析转子失衡、转子弯曲等故障的转频椭圆偏心率分布特点,总结出轴系热态不对中故障的偏心率变化规律.工程实例表明,改进的偏心率指标为区分不同类型的转频振动故障提供了有利的判别依据,适用于机组轴系热态对中变化过程的动态监测.

关键词：全息谱转频椭圆特征参数残余不平衡热态不对中

不同水分状况下秸秆覆盖量对玉米根、冠生长的影响

在线全文

学校读者我要写书评

暂无评论

干旱地区农业研究 2007年第5期25卷 46-51页

作者：张立强汪有科员学锋张吉祥于晓蕾刘超中国科学院水利部水土保持研究所长安大学地球科学与国土资源学院陕西西安710054 西北农林科技大学陕西杨凌712100

在遮雨棚控水条件下,采用盆栽的方式研究了不同秸秆覆盖量对玉米根、冠生长的影响。试验按对照(CK)和秸秆覆盖量0.3 kg/m2(SM0.3)、0.6 kg/m2(SM0.6)、0.9 kg/m2(SM0.9)、1.2 kg/m2(SM1.2)共设5个处理,水分按高水(占田间持水量的90%)和... 详细信息

在遮雨棚控水条件下,采用盆栽的方式研究了不同秸秆覆盖量对玉米根、冠生长的影响。试验按对照(CK)和秸秆覆盖量0.3 kg/m2(SM0.3)、0.6 kg/m2(SM0.6)、0.9 kg/m2(SM0.9)、1.2 kg/m2(SM1.2)共设5个处理,水分按高水(占田间持水量的90%)和低水(占田间持水量的60%)设两个水平。分别测定了玉米根、茎、叶、穗干重,根系垂直空间分布及叶片叶绿素相对含量等指标。结果表明:秸秆覆盖明显改变了玉米根系和地上部分的生长;高水条件下SM0.6处理玉米根系、茎秆、叶和穗干重均高于其它处理;低水条件下,地上部分干重SM1.2最大,SM0.6次之;根系的垂直空间分布与水分和覆盖条件都有密切的关系,覆盖措施主要影响下层根系的生长和发育。

关键词：控水秸秆覆盖玉米根系

Back-n white neutron source at CSNS and its applications

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2021年第1期32卷 95-104页

作者： jing-Yu Tang Qi An jiang-Bo Bai jie Bao Yu Bao Ping Cao Hao-lei Chen Qi-Ping Chen Yong-Hao Chen Zhen Chen Zeng-Qi Cui Rui-Rui Fan Chang-Qing feng Ke-Qing Gao Xiao-Long Gao Min-Hao Gu Chang-Cai Han Zi-jie Han Guo-Zhu He Yong-Cheng He Yang Hong Yi-Wei Hu Han-Xiong Huang Xi-Ru Huang Hao-Yu jiang Wei jiang Zhi-jie jiang Han-Tao jing ling Kang Bo li Chao li jia-Wen li Qiang li Xiao li Yang li jie liu Rong liu Shu-Bin liu Xing-Yan liu Ze Long Guang-Yuan Luan Chang-Jun Ning Meng-Chen Niu Bin-Bin Qi jie Ren Zhi-Zhou Ren Xi-Chao Ruan Zhao-Hui Song Kang Sun Zhi-jia Sun Zhi-Xin Tan Xin-Yi Tang Bin-Bin Tian li-jiao Wang Peng-Cheng Wang Zhao-Hui Wang Zhong-Wei Wen Xiao-Guang Wu Xuan Wu li-Kun Xie Xiao-yun Yang Yi-Wei Yang Han Yi li Yu Tao Yu Yong-ji Yu Guo-Hui zhang lin-Hao zhang Qi-Wei zhang Xian-Peng zhang Yu-liang zhang Zhi-Yong zhang Lu-Ping Zhou Zhi-Hao Zhou Ke-Jun Zhu 无 State Key Laboratory of Particle Detection and Electronics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China Department of Modern Physics University of Science and Technology of ChinaHefei 230026China Institute of Nuclear Physics and Chemistry China Academy of Engineering PhysicsMianyang 621900China Key Laboratory of Nuclear Data China Institute of Atomic EnergyBeijing 102413China Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China Spallation Neutron Source Science Center Dongguan 523803China State Key Laboratory of Nuclear Physics and Technology School of PhysicsPeking UniversityBeijing 100871China Northwest Institute of Nuclear Technology Xi’an 710024China University of Chinese Academy of Sciences Beijing 100049China Department of Engineering and Applied Physics University of Science and Technology of ChinaHefei 230026China State Key Laboratory of Particle Detection and Electronics University of Science and Technology of ChinaHefei 230026China The CSNS Back-n Collaboration

Back-streaming neutrons from the spallation target of the China Spallation Neutron Source(CSNS)that emit through the incoming proton channel were exploited to build a white neutron beam facility(the so-called Back-n white neutron source),which was completed in March *** Back-n neutron beam is very intense,at approximately 29107 n/cm2/s at 55 m from the target,and has a nominal proton beam with a power of 100 kW in the CSNS-I phase and a kinetic energy of 1.6 GeV and a thick tungsten target in multiple slices with modest moderation from the cooling water through the *** addition,the excellent energy spectrum spanning from 0.5 eV to 200 MeV,and a good time resolution related tothe time-of-flight measurements make it a typical white neutron source for nuclear data measurements;its overall performance is among that of the best white neutron sources in the *** with advanced spectrometers,detectors,and application utilities,the Back-n facility can serve wide applications,with a focus on neutron-induced cross-sectional *** article presents an overview of the neutron beam characteristics,the experimental setups,and the ongoing applications at Backn.

关键词： White neutron source Nuclear data measurements Experimental setups Neutron applications

在线全文

学校读者我要写书评

暂无评论

羊脆木的化学成分研究(Ⅱ)

云南大学学报（自然科学版） 2014年第6期36卷 903-906页

作者：罗蕾张吕丽李祖强曲云峰杨亚丹马国义云南师范大学化学化工学院云南昆明650500 云南大学化学科学与工程学院云南昆明650091 密西西比大学药学系

对滇产羊脆木(Pittosporum kerrii Craib)枝叶粗提物的有效部位进行化学成分研究.采用萃取、硅胶柱色谱、重结晶等方法,分离纯化得到8个单体,通过理化数据测定及波谱数据分析鉴定了它们的结构,分别是2-二十九烷酮(2-nonacosanone,1),1-... 详细信息

对滇产羊脆木(Pittosporum kerrii Craib)枝叶粗提物的有效部位进行化学成分研究.采用萃取、硅胶柱色谱、重结晶等方法,分离纯化得到8个单体,通过理化数据测定及波谱数据分析鉴定了它们的结构,分别是2-二十九烷酮(2-nonacosanone,1),1-二十九烷醇(nonacosan-1-ol,2),1-二十六烷醇(ceryl alcohol,3),三十二烷酸(lacceroic acid,4),三十烷酸(melissic acid,5),二十八烷酸(octacosanic acid,6),棕榈酸(palmitic acid,7),(2S,3S,4R,8E)-2-[(2R)-2-羟基二十三酰胺]-8-十八碳烯-1,3,4-三醇{(2S,3S,4R,8E)-2-[(2R)-2-hydroxytricosanoylamino]-8-octadecene-1,3,4-triol,8}.以上化合物均为首次从该植物中分离得到,化合物8为首次从该属植物中分离得到.药理试验表明化合物7、8具有细胞毒活性,对K562细胞的IC50分别为10.0、15.0μg/m L.

关键词：羊脆木化学成分细胞毒性神经酰胺脂肪酸脂肪醇

塔中海相碳酸盐岩凝析气田试采动态特征与开发技术对策

在线全文

学校读者我要写书评

暂无评论

天然气地球科学 2014年第12期25卷 2047-2057页

作者：韩剑发宋玉斌熊昶吉云刚张云峰杨磊何虎庄中国石油塔里木油田分公司新疆库尔勒841000 中国地质大学湖北武汉430074 西南石油大学四川成都610500

超深古老海相碳酸盐岩凝析气田的开发面临一系列世界级难题,特别是其多成因多期次叠合形成的复杂缝洞型储层和多充注点多期次的油气成藏以及高温高压、多相态流特征是制约油气上产的瓶颈问题。通过对塔里木盆地塔中海相碳酸盐岩凝析气田... 详细信息

超深古老海相碳酸盐岩凝析气田的开发面临一系列世界级难题,特别是其多成因多期次叠合形成的复杂缝洞型储层和多充注点多期次的油气成藏以及高温高压、多相态流特征是制约油气上产的瓶颈问题。通过对塔里木盆地塔中海相碳酸盐岩凝析气田100口试采井初期油气产量、自然递减、综合含水、相态变化等生产特征的解析,揭示出4种储层类型组合方式制约着产量递减规律;阐明了5种含水变化特征受控出4种储集体与水体的连接模式;形成了3种基本相态变化类型与2种组合类型受控于储层类型、地露压差、水体能量及组分梯度等基本认识。根据对储层类型、含水变化与相态变化认识,形成了优选井位、优化井型、注水注气及控制相变等提高凝析气田的开发效益的关键技术,推动了塔中海相碳酸盐岩大型凝析气田的开发,为类似的复杂油气田开发提供了借鉴。

关键词：塔中海相碳酸盐岩凝析气田试采动态开发对策

在线全文

学校读者我要写书评

暂无评论

采油污水的电催化杀菌工艺及其作用机理

环境科学与技术 2008年第10期31卷 108-111页

作者：张翼李云峰张妍嵇境鹏李建雷徐秀丽大庆石油学院化学化工学院黑龙江大庆163318 大庆石化公司黑龙江大庆163714 抚顺石化公司辽宁抚顺113001

利用形稳阳极借助于电催化方法对油田污水中的硫酸盐还原菌(SRB)、铁细菌(FB)、腐生菌(TGB)进行杀菌实验研究,确定了最佳操作条件,并对杀菌机理作了初步探讨。结果表明,在电流密度30mA/cm2、极板间距2cm、pH值5.0下处理30min时三种细菌... 详细信息

利用形稳阳极借助于电催化方法对油田污水中的硫酸盐还原菌(SRB)、铁细菌(FB)、腐生菌(TGB)进行杀菌实验研究,确定了最佳操作条件,并对杀菌机理作了初步探讨。结果表明,在电流密度30mA/cm2、极板间距2cm、pH值5.0下处理30min时三种细菌的杀菌率均达100%。通过对杀菌机理的初步探讨表明,在电催化过程中产生的活性氯对杀菌效果起主要作用。

关键词：油田污水硫酸盐还原菌铁细菌腐生菌电催化

Searching for ^(76)Ge neutrinoless double beta decay with the CDEX-1B experiment

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2024年第10期48卷 11-22页

作者： Bing-Tao zhang Jun-Zheng Wang li-Tao Yang Qian Yue Ke-Jun Kang Yuan-jing li Hai-Peng An C.Greeshma jian-Ping Chang yun-Huan Chen jian-Ping Cheng Wen-Han Dai Zhi Deng Chang-Hao Fang Xin-Ping Geng Hui Gong Qiu-Ju Guo Xu-Yuan Guo li He sheng-Ming He jin-Wei Hu Han-Xiong Huang Tu-Chen Huang Hai-Tao jia Xi jiang S.Karmakar Hao-Bin li jian-Min li jin li Qian-yun li Ren-Ming-jie li Xue-Qian li Yu-Lan li Yi-Fan liang Bin liao Fong-Kay lin Shin-Ted lin jia-Xuan liu Shu-Kui liu Yan-Dong liu Yu liu Yuan-Yuan liu Zhong-Zhi liu Hao Ma Yu-Cai Mao Qi-Yuan Nie jin-Hua Ning Hui Pan Ning-Chun Qi jie Ren Xi-Chao Ruan Ze She Manoj Kumar Singh Tian-Xi Sun Chang-jian Tang Wei-You Tang Yang Tian Guang-Fu Wang li Wang Qing Wang Yu-feng Wang yun-Xiang Wang Henry-Tsz-King Wong Shi-Yong Wu Yu-Cheng Wu Hao-Yang Xing Rui Xu Yin Xu Tao Xue Yu-Lu Yan Nan Yi Chun-Xu Yu Hai-Jun Yu jian-feng Yue Ming Zeng Zhi Zeng feng-Shou zhang lei zhang Zhen-Hua zhang Zhen-Yu zhang Kang-Kang Zhao Ming-Gang Zhao ji-Fang Zhou Zu-Ying Zhou jing-Jun Zhou Key Laboratory of Particle and Radiation Imaging(Ministry of Education)and Department of Engineering Physics Tsinghua UniversityBeijing 100084 Department of Physics Tsinghua UniversityBeijing 100084 Institute of Physics Academia SinicaTaipei 11529 NUCTECH Company Beijing 100084 YaLong River Hydropower Development Company Chengdu 610051 College of Nuclear Science and Technology Beijing Normal UniversityBeijing 100875 College of Physics Sichuan UniversityChengdu 610065 School of Physics Peking UniversityBeijing 100871 Department of Nuclear Physics China Institute of Atomic EnergyBeijing 102413 Sino-French Institute of Nuclear and Technology Sun Yat-sen UniversityZhuhai 519082 School of Physics Nankai UniversityTianjin 300071 Department of Physics Banaras Hindu UniversityVaranasi 221005 Department of Physics Beijing Normal UniversityBeijing 100875

We operated a p-type point contact high purity germanium(PPCGe)detector(CDEX-1B,1.008 kg)in the China jinping Underground Laboratory(CJPL)for 500.3 days to search for neutrinoless double beta(0νββ)decay of ^(76)Ge.A total of 504.3 kg⋅day effective exposure data was *** anti-coincidence and the multi/single-site event(MSE/SSE)discrimination methods were used to suppress the background in the energy region of interest(ROI,1989–2089 keV for this work)with a factor of 23.A background level of 0.33 counts/(keV⋅kg⋅yr)was *** lower limit on the half life of^(76)Ge 0νββdecay was constrained as T_(1/2)^(0ν)>1.0×10^(23)yr(90%C.L.),corresponding to the upper limits on the effective Majorana neutrino mass:<3.2–7.5 eV.

关键词： neutrinoless double beta decay CDEX point-contact germanium detector ^(76)Ge

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

西藏唐北地区湖泊动态及空间格局预测

应用生态学报 2019年第8期30卷 2793-2802页

作者：张路李炳章郭克疾刘峰宗嘎李昕宇吕永磊欧阳志云中国科学院生态环境研究中心城市与区域生态国家重点实验室北京100085 西藏自治区林业调查规划研究院拉萨850000 国家林业局中南林业调查规划设计院长沙410014 西藏自治区林业厅拉萨850000 国家林业和草原局昆明勘察设计院昆明650041

本研究评估了西藏唐古拉山以北地区(唐北地区)湖泊动态并预测了湖泊空间格局变化.使用面向对象分类和光谱角向量变化检测方法生成了2000-2015年西藏唐北地区每5年一期的生态系统分布数据.以此为基础,分析了湖泊与其他生态系统之间的转... 详细信息

本研究评估了西藏唐古拉山以北地区(唐北地区)湖泊动态并预测了湖泊空间格局变化.使用面向对象分类和光谱角向量变化检测方法生成了2000-2015年西藏唐北地区每5年一期的生态系统分布数据.以此为基础,分析了湖泊与其他生态系统之间的转换和空间格局特征,评估了湖泊空间格局的动态及其与相关自然地理因素的关系.通过增强回归树识别了不同因素对湖泊动态的贡献,使用GEOMOD模型预测了湖泊到2030年的空间变化.结果表明:唐北地区在2000-2015年间湖泊增加了14.2%,是唐北地区生态系统变化的主要形式之一.区域内15个面积大于10 km2的湖泊有10个增加,另有5个减少,且缩减量较低.通过空间格局分析发现,唐北地区湖泊斑块表现为面积和数量同时增加,大斑块面积比重略有上升.扩张幅度高的湖泊多分布于海拔高、坡度大、温度低、降水少、距离冰川近的区域.位于现有湖泊周边、温度低、降水少、坡度小的区域转变为湖泊的几率较高.根据过去15年的趋势,到2030年,唐北地区湖泊将继续增加119 km2,主要变化形式从大湖扩张转变为小型水面扩张.

关键词：湖泊面积动态青藏高原空间格局 GEOMOD模型