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Injected spectrum for TeV γ-ray emission from the galactic center

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Research in Astronomy and Astrophysics 2009年第7期9卷 761-769页

作者： Yan-Ping Wang Ye lu li Chen National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Department of Astronomy Beijing Normal University Beijing 100875 China

The detection of very high energy γ-ray emission from the Galactic center has been reported by four independent groups. One of these γ-ray sources, the 10 TeV -γ-ray radiation reported by HESS, has been suggested as having a hadronic origin when relativistic protons are injected into and interact with the dense ambient gas. Assuming that such relativistic protons required by the hadronic model come from the tidal disruption of a star by the massive black hole of Sgr A＊, we explore the spectrum of the relativis- tic protons. In the calculations, we investigate cases where different types of stars are tidally disrupted by the black hole of Sgr A＊, and we consider that different diffusion mechanisms are used for the propagation of protons. The initial energy distribution of the injected spectrum of protons is assumed to follow a power-law with an exponential cut-off, and we derive the different indices of the injected spectra for the tidal disruption of different types of stars. For the best fit to the spectrum of photons detected by HESS, the spectral index of the injected relativistic protons is about 2.05 when a red giant is tidally disrupted by the black hole of Sgr A＊ and the diffusion mechanism is the Effective Confinement of Protons.

关键词： black hole physics - galaxies jets - Galaxy center

Improving the real-time performance of Ethernet for plant automation(EPA) based industrial networks

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Journal of Zhejiang University-Science C(Computers and Electronics) 2013年第6期14卷 433-448页

作者： li lu Dong-qin FENG Jian CHU Institute of Cyber-Systems and Control Zhejiang University State Key Laboratory of Industrial Control Technology Zhejiang University

Real-time Ethernet(RTE) control systems with critical real-time requirements are called fast real-time(FRT) *** improve the real-time performance of Ethernet for plant automation(EPA),we propose an EPA-FRT *** minimum macrocycle of EPA networks is reduced by redefining the EPA network frame format,and the synchronization process is modified to acquire higher accuracy.A multi-segmented topology with a scheduling scheme is introduced to increase effective bandwidth utilization and reduce protocol overheads,and thus to shorten the communication cycle *** analysis and practical tests on a prototype system show the effectiveness of the proposed scheme,which achieves the best performance at small periodic payload in large scale systems.

关键词： Ethernet for plant automation (EPA) Fast real-time (FRT) system Real-time Ethernet (RTE) Scheduling scheme171 ~ ~l ~nI~ ]Ui^umanf onrla* A ~| F numh~* TDg02

Effect of Thermomechanical Processing on Mechanical Properties of Hot Rolled Multiphase Steel

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Journal of Iron and Steel Research International 2008年第1期15卷 55-60页

作者： li Zhuang WU Di lu Hui-sheng Department of Material Engineering Shenyang Institute of Aeronautical Engineering Shenyang 110034 Liaoning China State Key Lab of Rolling and Automation Northeastern University Shenyang 110004 Liaoning China Department of Science and Technology Information China Iron and Steel Research Institute Group Beijing 100081 China

The effect of thermomechanical processing（TMP）on the mechanical properties of hot rolled multiphase steel was *** was conducted using a laboratory hot rolling mill,in which three different kinds of finish rolling deformation degrees and temperatures were *** results indicate that polygonal ferrite,granular bainite,and a considerable amount of stabilized retained austenite can be obtained by *** stability of the retained austenite increases with decreasing finish rolling temperature and increasing finish rolling deformation *** tensile strength（σb）,total elongation（δ）,and the product of ultimate tensile strength by total elongation（σb·δ）for 50% reduction at finish rolling temperature of 700 ℃ reach maximum values [791 MPa,36% and 28 476（MPa·%）,respectively].

关键词： hot rolled multiphase steel finish rolling deformation degree finish rolling temperature retained austenite mechanical property

鄂西—渝东地区上二叠统大隆组页岩气富集条件与勘探有利区

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天然气工业 2024年第5期44卷 1-15页

作者：李世臻周志李飞沈斌徐秋晨宋腾张小涛杨晓光胡才志王超魏思宇王昱荦卢妍欣中国地质调查局油气资源调查中心中国地质调查局非常规油气地质重点实验室国家地质实验测试中心

近年来,鄂西—渝东地区多口井在二叠系大隆组获得页岩气重要发现和工业气流,展现出新层系海相页岩气良好的勘探开发前景,深化其地质认识对于指导下一步页岩气勘探具有重要意义。为此,基于岩心观察、薄片及扫描电镜观察、测/录井和有机... 详细信息

近年来,鄂西—渝东地区多口井在二叠系大隆组获得页岩气重要发现和工业气流,展现出新层系海相页岩气良好的勘探开发前景,深化其地质认识对于指导下一步页岩气勘探具有重要意义。为此,基于岩心观察、薄片及扫描电镜观察、测/录井和有机地球化学数据分析,系统研究了该地区页岩沉积特征、储层特征、有机地球化学特征、含气性和保存条件,明确了大隆组海相页岩气勘探有利区。研究结果表明:①晚二叠世大隆期,该区发育深水台盆相沉积,富有机质页岩发育厚度10~60 m,现今埋深具有盆内埋深大、盆外埋深浅的特征;②大隆组自下而上划分为3段,一段以硅质页岩为主,二段岩性较为复杂,三段以混合质页岩为主,测井响应上表现为高自然伽马、高补偿中子、高声波时差、低电阻率、低密度、电阻率向底部逐渐降低的“三高两低一降”特征;③大隆组页岩脆性矿物以石英和方解石为主,平均值分别为40.58%和23.76%,储集空间分为孔隙(有机质孔、矿物颗粒间孔、粒间溶蚀孔、粒内溶蚀孔)和裂缝(矿物层间缝、有机质与矿物间缝、有机质内裂缝)2大类7种类型,以有机质孔为主,孔径分布呈现“四峰”特征,孔体积集中介于1~10 nm和500~5000 nm两个孔径区间;④大隆组有机质丰度高、储层非均质性强、热演化程度高、有机质类型以Ⅱ1型为主、Ⅱ2型为辅,有机质孔发育;⑤大隆组页岩具有较高的含气量,良好的顶底板条件发挥了重要的封闭作用;盆内受构造抬升剥蚀和断裂影响小,保存条件整体较好,盆外残留向斜核部保存条件较好。结论认为:①大隆组是四川盆地页岩气勘探的新领域,在盆地内发育5个勘探有利区,面积合计5500 km^(2),可加快勘探评价节奏;②在盆外发育7个勘探有利区,面积合计6700 km^(2),应优选残留面积大的有利区开展风险勘探,寻找新的突破和发现。

关键词：海相页岩气新领域鄂西—渝东地区上二叠统大隆组富集地质条件勘探有利区

伊犁洪海沟矿区富铀煤的元素地球化学以及铀的价态特征

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地质学报 2024年第8期98卷 2439-2451页

作者：李家新王文峰白洪阳陆青锋何鑫王文龙师志龙中国矿业大学资源与地球科学学院江苏徐州221116 新疆大学地质与矿业工程学院新疆乌鲁木齐830047 洛阳理工学院土木工程学院河南洛阳471023 核工业二一六大队新疆乌鲁木齐830011

铀是重要能源矿产和国家战略资源,煤岩型铀矿对我国核能产业可持续发展和“双碳”目标实现具有重要意义。本文采用X射线荧光光谱(XRF)、电感耦合等离子体质谱(ICP-MS)和X射线光电子能谱(XPS)等手段,研究了伊犁盆地洪海沟矿区煤的元素地... 详细信息

铀是重要能源矿产和国家战略资源,煤岩型铀矿对我国核能产业可持续发展和“双碳”目标实现具有重要意义。本文采用X射线荧光光谱(XRF)、电感耦合等离子体质谱(ICP-MS)和X射线光电子能谱(XPS)等手段,研究了伊犁盆地洪海沟矿区煤的元素地球化学、富铀因素以及铀活化迁移过程的价态变化特征。结果表明:①洪海沟煤中U超常富集,平均含量为258.91μg/g。石炭纪—二叠纪中—酸性火成岩和海西期花岗岩是煤中铀的物质来源,稳定的单斜构造,头屯河组砂砾岩和粗砂岩的岩性组合,晚侏罗世以来干旱气候及后生富铀溶液的入渗共同控制煤层中U、Re、Se、Mo等元素共同富集。②煤岩型铀矿的形成与氧化环境中U6+以络合物或酸根形式迁移,氧化—还原过渡环境中富铀含氧流体中U6+被还原成U4+沉淀富集有关。洪海沟矿区弱氧化—还原过渡环境高价态的变价元素被还原,以Se-U-Re-Mo模式共同富集于煤层顶部。③洪海沟矿区“上铀下煤”矿产资源分布和铀矿下部多煤层的发育,需要合理划分煤-铀矿产资源之间保护区距离,上部砂岩型铀矿优先进行地浸开采,下部煤岩型铀矿采用井工开拓方式进行“煤炭地下气化+煤灰原位地浸开采”,将煤灰中铀提取至地表利用,实现煤-铀资源协调开采利用。

关键词：富铀煤元素地球化学价态协调开采

Direct imaging and determination of the crystal structure of six-layered graphdiyne

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Nano Research 2018年第3期11卷 1714-1721页

作者： Chao li Xiuli lu Yingying Han Shangfeng Tang Yi Ding Ruirui liu Haihong Bao Yuliang li Jun luo Tongbu lu Center for Electron Microscopy TUT-FEI Joint Laboratory Tianjin Key Laboratory of Advanced Porous Functional Materials Institute for New Energy Materials & Low-Carbon Technologies School of Materials Science and Engineering Tianjin University of Technology Tianjin 300384 China Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 China

Since its discovery, the direct imaging and determination of the crystal structure of few-layer graphdiyne has proven difficult because it is too delicate under irradiation by an electron beam. In this work, the crystal structure of a six-layered graphdiyne nanosheet was directly observed by low-voltage transmission electron microscopy （TEM） using low current density. The combined use of high-resolution TEM （HRTEM） simulation, electron energy-loss spectroscopy, and electron diffraction revealed that the as-synthesized nanosheet was crystalline graphdiyne with a thickness of 2.19 nm （corresponding to a thickness of six layers） and showed ABC stacking. Thus, this work provides direct evidence for the existence and crystal structure of few-layer graphdiyne, which is a new type of two-dimensional carbon material complementary to graphene.

关键词： few-layer graphdiyne crystal structure low-voltage transmissionelectron microscopy

Single-cell profiling of the pig cecum at various developmental stages

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INVESTIGATION ON STABIliTY OF PZT/EPOXY PIEZOCOMPOSITE WITH PRESSURE AND TEMPERATURE

动物学研究 2024年第1期

作者： Yan-Yuan Xiao Qing Zhang Fei Huang lin rao Tian-Xiong Yao Si-Yu Yang Lei Xie Xiao-Xiao Zou li-Ping Cai Jia-Wen Yang Bin Yang lu-Sheng Huang

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Acta Mechanica Solida Sinica 2009年第3期22卷 226-231页

作者： likun Wang Yuanyuan Wan li li Lei Qin Yi lu Beijing Key Laboratory for Sensor Beijing Information Science and Technology University Beijing 100101 China Computer Science and Technology Department Shenyang Institute of Chemical Technology 11 Economic Development District Shenyang 110142 China The Department of Foreign Languages Teaching Yunnan University Kunming 650091 China

With the universal test machine and temperature test chamber, the effect of pressure and temperature on the behavior of 1-3 and 1-3-2 piezocomposites prepared with PZT/epoxy in our lab has been investigated through electrical impedance and dielectric analysis. The permittivity, resonant frequency and dielectric loss of the composites have been measured under vertical stress and temperature, and the variety of the material properties under pressure and temperature could also be obtained. The pressure and temperature stability of the composites have been assessed through experiments. The data of these two types of composites indicated that the stability of 1-342 composite with pressure was better than that of 1-3 composite, and two composites have almost the same dielectric stability with temperature. However, 1-3-2 composite showed slower frequency variation than 1-3 composite.

关键词： piezoelectric composite directional pressure temperature stability

A comparison of n-γ discrimination by the rise-time and zero-crossing methods

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Science China(Physics,Mechanics & Astronomy) 2010年第8期53卷 1453-1459页

作者： Jie Yan Rong liu Cheng li li Jiang XinXin lu University of Science and Technology of China Department of Modern Physics Hefei China (GRID:grid.59053.3a) (ISNI:***) Chinese Academy of Engineering Physics Institute of Nuclear Physics and Chemistry Mianyang China (GRID:grid.249079.1) (ISNI:***) Chinese Academy of Engineering Physics Institute of Nuclear Physics and Chemistry Mianyang China (GRID:grid.249079.1) (ISNI:***) University of Science and Technology of China Department of Modern Physics Hefei China (GRID:grid.59053.3a) (ISNI:***)

The n-γ discrimination performance of two experimental arrangements based on the rise-time method and the zero-crossing method was compared for a 50.8 mm-diametered and 50.8 mm-high BC501A liquid scintillator coupled to a 50.8 mm-diametered 9807B photomultiplier in this work. The low energy limitation of the detected neutron with different detector high voltages and the figure of merit of the n-γ discrimination in four neutron energy regions (1–2 MeV, 0.75–1 MeV, 0.5–0.75 MeV and below 0.5 MeV) were studied by using the Am-Be neutron source. Under a time statistical model of the photoelectron emission process in scintillation counters, the intrinsic capability of the n-γ discrimination performance under the optimal condition was evaluated. The experimental results of the zero-crossing method demonstrate a better n-γ. discrimination performance than those of the rise-time method, which is consistent with the calculated results.

关键词： rise-time method zero-crossing method n-g discrimination time statistics analysis BC501A scintillation detector