检索结果-南通市图书馆

Geochemical characteristics of rare earth elements in Wuhan section of the Yangtze River

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental sciences 1995年第1期7卷 44-51页

作者： Wang lijun Zhang Shen Zhang Chaosheng(institute of Geography,chinese academy of sciences,beijing 100101,china)li Xiuxia(institute of high energy physics,chinese academy of sciences,beijing 100080,china) Inst of Geog Chinese Academy of Sciences Beijing China China

ＧｅｏｃｈｅｍｉｃａｌｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｒａｒｅｅａｒｔｈｅｌｅｍｅｎｔｓｉｎＷｕｈａｎｓｅｃｔｉｏｎｏｆｔｈｅＹａｎｇｔｚｅＲｉｖｅｒＷａｎｇＬｉｊｕｎ；ＺｈａｎｇＳｈｅｎ；ＺｈａｎｇＣｈａｏｓｈｅ... 详细信息

ＧｅｏｃｈｅｍｉｃａｌｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｒａｒｅｅａｒｔｈｅｌｅｍｅｎｔｓｉｎＷｕｈａｎｓｅｃｔｉｏｎｏｆｔｈｅＹａｎｇｔｚｅＲｉｖｅｒＷａｎｇＬｉｊｕｎ；ＺｈａｎｇＳｈｅｎ；ＺｈａｎｇＣｈａｏｓｈｅｎｇ（ＩｎｓｔｉｔｕｔｅｏｆＧｅｏ...

关键词： geochemical characteristics rare earth elements Yangtze River

Systematic distortion in cosmic microwave background maps

在线全文

学校读者我要写书评

暂无评论

Science china(physics,Mechanics & Astronomy) 2009年第5期52卷 804-808页

作者： liU Hao 1,3 &li TiPei 1,2 1Key Laboratory of Particle Astrophysics,institute of high energy physics,chinese academy of sciences,beijing 100049,china 2Center for Astrophysics,Tsinghua University,beijing 100084,china 3 Graduate University of chinese academy of sciences,beijing 100049,china Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing China Graduate University of chinese academy of sciences Beijing China Center for Astrophysics Tsinghua University Beijing China

To minimize instrumentally the induced systematic errors,cosmic microwave background(CMB)anisotropy experiments measure temperature differences across the sky using pairs of horn antennas, temperature map is recovered from temperature difference obtained in sky survey through a map-making *** inspect and calibrate residual systematic errors in the recovered temperature maps is important as most previous studies of cosmology are based on these *** analyzing pixel-ring coupling and latitude dependence of CMB temperatures,we find notable systematic devia- tion from CMB Gaussianity in released Wilkinson Microwave Anisotropy Probe(WMAP)*** detected deviation cannot be explained by the best-fit LCDM cosmological model at a confidence level above 99%and cannot be ignored for a precision cosmology study.

关键词： cosmology cosmic microwave background methods data analysis

Advances of graphdiyne-supported metal catalysts in thermocatalytic reactions

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第4期17卷 2223-2233页

作者： Jia Yu Yida Yang Yuliang li Changyan Cao weiguo Song beijing National Laboratory for Molecular sciences CAS Research/Education Center for Excellence in Molecular SciencesLaboratory of Molecular Nanostructures and NanotechnologyInstitute of ChemistryChinese Academy of SciencesBeijing 100190China School of Chemical sciences University of Chinese Academy of SciencesBeijing 100049China beijing National Laboratory for Molecular sciences CAS Research/Education Center for Excellence in Molecular SciencesLaboratory of organic solidsInstitute of ChemistryChinese Academy of SciencesBeijing 100190China

Supported metal catalysts are widely used in the modern chemical *** electronic interaction between supports and active components is of great significance for heterogeneous ***(GDY),a new type of carbon allotrope with sp-hybridized carbon atoms,πconjugate structure,and electron transmission capability,is a promising candidate as catalyst *** years have witnessed the rapid progress of GDY-supported metal catalysts for different catalysis *** that most processes in the current chemical industry are thermocatalytic reactions,we herein give an overview about the advances and particular characteristics of GDY-supported catalysts in these *** geometric structure and electronic properties of GDY are first ***,the synthesis methods for GDY-supported metal catalysts and their applications in thermocatalytic reactions are discussed,in which the effect of electronic interaction on catalytic performance is ***,the current challenges and future directions of GDY-supported metal catalysts for thermocatalysis are *** is expected that this review will enrich our understanding of the advances of GDY as a superior support for metal catalysts in thermocatalytic reactions.

关键词： graphdiyne metal catalysts thermocatalytic reactions heterogeneous catalysis

Compression behavior of Zr_(41)Ti_(14)Cu_(12.5)Ni_(10)Be_(22.5) bulk metallic glass up to 24 GPa

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

Science china(physics,Mechanics & Astronomy) 2005年第3期48卷 319-324页

作者： li Gong 1, 2 , ZHAN Zaiji 2 , liU Jing 3 , YUN Jinku 1 , SUN liling 2 , liU Riping 1 , ZHANG Jun 2 & WANG Wenkui 1, 2 1. Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, china 2. Center for Condensed Matter physics, institute of physics, chinese academy of sciences, beijing 100080, china 3. BSRF, institute of high energy physics, chinese academy of sciences, beijing 100039, china Key Laboratory of Metastable Materials Science and Technology Yanshan University Qinhuangdao China Center for Condensed Matter physics Institute of Physics Chinese Academy of Sciences Beijing China BSRF Institute of High Energy Physics Chinese Academy of Sciences Beijing China

The compression of a Zr41Ti14Cu12.5Ni10Be22.5 bulk metallic glass (BMG) is investigated at room temperature up to 24 GPa using in-situ high pressure energy dispersive X-ray diffraction with a synchrotron radiation source. The pressure-induced structural relaxation is exhibited. It is found that below about 8 GPa, the existence of excess free volume contributes to the rapid structural relaxation, which gives rise to the rapid volumetric change, and the structural relaxation results in the structural stiffness under higher pressure.

关键词： bulk metallic glass, high pressure, structural relaxation, synchrotron radiation.

Some characteristics of the atmosphere during an adiabatic process

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2006年第6期16卷 644-648页

作者： GAO li, li Jianping and REN Hongli (LASG, institute of Atmospheric physics, chinese academy of sciences, beijing 100029, china Graduate School of chinese academy of sciences, beijing 100049, china National Climate Center, Laboratory of Climate Studies, china Meteorological Administration, beijing 100081, china) LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Graduate School of chinese academy of sciences Beijing 100049 China National Climate Center Laboratory of Climatic Studies China Meterological Administration Beijing 100081 China

Some important characteristics of the atmosphere during an adiabatic process are investigated, which include the invariability of atmospheric entropy range and local surface potential temperature, the conservation of the atmospheric mass intervened between any isentropic surface and the ground, and the isentropic surface intersecting with the ground. The analysis shows that the atmospheric reference state (ARS) for investigation on available potential energy (APE) should be defined objectively as the state which could be approached from the existing atmosphere by adiabatic adjustment, and be related to initial atmospheric state before adjustment. For the initial atmosphere state at any time, its corresponding ARS is different from the one at another time. Based on the above-mentioned conclusions, the reference state proposed by Lorenz cannot be obtained physically, so a new conception, the conditional minimum total potential energy, is put forward in order to objectively investigate atmospheric APE.

关键词： available potential energy adiabatic isentropic surface atmospheric reference state conditional minimum total potential energy.

Simulation of the in-flight calibration of the collimator alignment and PSF for HXMT

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china(physics,Mechanics & Astronomy) 2010年第S1期53卷 47-50页

作者： XIONG Shaolin,li XinQiao,QU JinLu & LU FangJun Key Laboratory for Particle Astrophysics,institute of high energy physics,chinese academy of sciences(CAS),beijing 100049,china Key Laboratory for Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences (CAS) Beijing China

The Hard X-ray Modulation Telescope(HXMT) is an X-ray astronomical satellite in 1-250 keV,consisting of three collimated *** present the in-flight calibration approach of the collimator alignment and Point Spread Function(PSF) for HXMT,using both the direct fitting method and the imaging *** to observational simulations of the Crab Nebula,we find that these two methods produce almost the same calibration accuracy of the alignment,and with a one-day scanning observation,the alignment can be calibrated to better than 0.45' and 0.1' along the wide and narrow directions of the Field of View(FOV) for a detector module,which corresponds to a localization accuracy of better than 0.1' and meets the scientific requirement.

关键词： HXMT alignment PSF calibration

light collection of the POLAR detector

在线全文

学校读者我要写书评

暂无评论

Science china(physics,Mechanics & Astronomy) 2010年第S1期53卷 43-46页

作者： DONG YongWei,li YanGuo,WU BoBing,ZHANG YongJie & ZHANG ShuangNan Key Laboratory of Particle Astrophysics,institute of high energy physics,chinese academy of sciences,beijing 100049,china Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing China

POLAR is a compact polarimeter dedicated to measuring the polarization of GRBs between 50-350 *** light collection of 200 mm×6 mm×6 mm plastic bars has been simulated and optimized in order to get uniform response to X-rays at different points along one single *** to the Monte Carlo results,the amplitude uniformity strongly depends on the level of polishing of the scintillator surface and the covering.A uniformity of 89% is achieved with a prototype constructed by a non position-sensitive PMT and an array of 4×4 bars.

关键词： plastic scintillator light collection gamma-ray burst polarimeter

energy dissipation mechanism and ballistic characteristic optimization in foam sandwich panels against spherical projectile impact

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第5期35卷 108-122页

作者： Jianqiang Deng Tao liu liming Chen Xin Pan Jingzhe Wang Shaowei Zhu weiguo li College of Aerospace Engineering Chongqing UniversityChongqing 400030China State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing 400030China Chongqing Key Laboratory of Heterogeneous Material Mechanics Chongqing UniversityChongqing 400030China State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China

This study systematically examines the energy dissipation mechanisms and ballistic characteristics of foam sandwich panels(FSP)under high-velocity impact using the explicit non-linear finite element *** on the geometric topology of the FSP system,three FSP configurations with the same areal density are derived,namely multi-layer,gradient core and asymmetric face sheet,and three key structural parameters are identified:core thickness(t_(c)),face sheet thickness(t_(f))and overlap face/core number(n_(o)).The ballistic performance of the FSP system is comprehensively evaluated in terms of the ballistic limit velocity(BLV),deformation modes,energy dissipation mechanism,and specific penetration energy(SPE).The results show that the FSP system exhibits a significant configuration dependence,whose ballistic performance ranking is:asymmetric face sheet>gradient core>*** mass distribution of the top and bottom face sheets plays a critical role in the ballistic resistance of the FSP *** BLV and SPE increase with tf,while the raising tcor noleads to an increase in BLV but a decrease in ***,a face-core synchronous enhancement mechanism is discovered by the energy dissipation analysis,based on which the ballistic optimization procedure is also conducted and a design chart is *** study shed light on the anti-penetration mechanism of the FSP system and might provide a theoretical basis for its engineering application.

关键词： Sandwich panel Numerical simulation Ballistic resistance Specific penetration energy energy analysis

SVOM gamma ray monitor

在线全文

学校读者我要写书评

暂无评论

Science china(physics,Mechanics & Astronomy) 2010年第S1期53卷 40-42页

作者： DONG YongWei,WU BoBing,li YanGuo,ZHANG YongJie & ZHANG ShuangNan Key Laboratory of Particle Astrophysics,institute of high energy physics,chinese academy of sciences,beijing 100049,china Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing China

The space-based multi-band astronomical Variable Object Monitor(SVOM) mission is dedicated to the detection,localization and broad-band study of gamma-ray bursts(GRBs) and other high-energy transient *** gamma ray monitor(GRM) onboard is designed to observe GRBs up to 5 *** this instrument,one of the key GRB parameters,Epeak,can be easily measured in the hard X-ray *** can achieve a detection rate of 100 GRBs per year which ensures the scientific output of SVOM.

关键词： gamma-ray burst Epeak triple phoswich