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Distributions of arsenic and essential elements in pinna of arsenic hyperaccumulator Pteris vittata L.

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science china(Life sciences) 2005年第1期48卷 18-24页

作者： CHEN Tongbin, HUANG Zechun, HUANG Yuying & LEI Mei laboratory of Environmental Remediation, institute of Geographic {2.s and Natural Resources Research, {3. academy of {2.s, beijing 100101, china laboratory of synchrotron radiation, institute of {12. Energy {13., {3. academy of {2.s, beijing 10003., china laboratory of Environmental Remediation Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing100101 China laboratory of synchrotron {2. Institute of High Energy Physics Chinese Academy of Sciences Beijing100039 China

The distributions of arsenic and 6 essential elements in the pinna of As hyperaccumulator, Pteris vittata L., were studied using synchrotron radiation X-ray fluorescence (SRXRF). Significant correlation between the distribution and mobility of the elements revealed that SRXRF study on the elemental distribution was feasible to inspect the transportations of elements in plants. The distribution of As in the pinna showed that As had great abilities to be transported in xylem vessels and from xylem to mesophyll. The distribution of K, one of the most mobile elements in plants, was similar to that of As, whereas the distributions of Fe and Ca with less mobility in plants were almost opposite to that of As in the pinna.

关键词： hyperaccumulator, chinese brake (Pteris vittata L.), arsenic, element, distribution, SRXRF.

Theoretical and experimental researches on C-band three-cavity transit-time effect oscillator

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science china({2.,Mechanics & Astronomy) 2004年第3期47卷 310-329页

作者： FAN Zhikai1, LIU Qingxiang1, CHEN Daibing1, TAN Jie1 & ZHOU Haijing2.1. institute of Applied Electronics, chinese {2. of Engineering physics, Mianyang 62.900, china 2. institute of Applied physics and Computational Mathematics, beijing 100088, china 1. institute of Applied Electronics Chinese Academy of Engineering Physics 621900 Mianyang China 2. institute of Applied physics and Computational Mathematics 100088 Beijing China

The C-band three-cavity transit-time effect oscillator (3. TTTO) is a novel high power microwave device based on the transit-time effect of the three-cavity (3.) resonator. The operational principle of this device is briefly expounded in this paper, and the theoretical and experimental researches on the radial insulation diode, the 3. resonator, the double-gap output cavity and the circular waveguide bevel cut radiation antenna are presented in detail. By using the analytic method, the eigen modes and their field distributions of the 3. resonator are developed, and some basic laws of the transit-time effect are obtained in non-π mode field of the 3. resonator. At last, the experimental results are given. This device generated RF peak power in excess of 400MW with 15ns FWHM, and its beam-wave power conversion efficiency is about 17%.

关键词： C-band, three-cavity (3.) resonator, transit-time effect, high power microwave, oscillator.

用原位x射线小角散射研究块体非晶合金Zr_(55)Cu_(3.)Al_(10)Ni_5的结构弛豫

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物理学报 2003年第9期52卷 2219-2222页

作者：柳义柳林王俊赵辉荣利霞董宝中中国原子能科学研究院北京102413 华中科技大学材料学院武汉430074 中国科学院高能物理研究所同步辐射实验室北京100039

应用同步辐射x射线小角散射法在原位对块体非晶合金Zr55Cu3. Al1 0 Ni5在等温退火过程中的微结构变化进行研究 .实验表明 :在等温退火过程中电子密度涨落反映了晶化之前的结构弛豫过程 ;在一定的退火温度下、随退火时间的增加 ,拓扑短... 详细信息

应用同步辐射x射线小角散射法在原位对块体非晶合金Zr55Cu3. Al1 0 Ni5在等温退火过程中的微结构变化进行研究 .实验表明 :在等温退火过程中电子密度涨落反映了晶化之前的结构弛豫过程 ;在一定的退火温度下、随退火时间的增加 ,拓扑短程序弛豫与化学短程序弛豫之间存在一个电子密度均匀化的过程 ;导致这两种弛豫过程转变的退火时间与退火温度有关 ,温度越高。

关键词：原位x射线小角散射块体非晶合金等温退火结构弛豫 Zr55Cu3.Al10Ni5合金电子密度涨落

The formation process and cloud physical characteristics for a typical downburstproducing thunderstorm in beijing

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chinese science Bulletin 2003年第S2期48卷 77-82页

作者： GUO Xueliang FU Danhong institute of Almospherie physics, {2. {3. of sciences, beijing 10002.. china chinese Acad Sci Inst Atmospher Phys Beijing 100029 Peoples R China

The formation process and characteristics ofcloud physical structure of a severe thunderstorm accompa-nied with strong wind on 2. August, 2.01 in beijing wasstudied using PSU/NCAR mesoscale model ( MM5) couplingwith a severe storm model with hail-bin micro{3.. Theresults show that the specific topography and distributionfeatures of cold/warm current in the beijing region playedprominent roles in forming, developing and maintaining thesevere storm. Due to solar radiation heating and topographiclifting, the convective cells were easily formed when thewesterly airflow passed over high mountainous regions inbeijing. The warm and wet air entered the cloud from itsfrontage and enhanced the convection, and formed a largeamount of graupel/hail particles at the middle and upperportion of the clouds. The precipitation was primarilyformed due to melting of graupel/hail particles. The strongdowndraft was mainly produced by negative buoyancy dueto loading, melting of graupel/hail particles as well asevaporative cooling of rain water. The divergent airflow in-duced by the strong downdraft led to the disastrous burstwinds at the surface and also forced lifting of warm and wetairflow in the moving direction of the storm and formed newclouds that further promoted and maintained the storm de-velopment.

关键词： beijing region thunderstorm and disastrous wind cluud physical features.

Preliminary results of a regional air-sea coupled model over East Asia

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chinese science Bulletin 2010年第21期55卷 2295-2305页

作者： LI Tao ZHOU GuangQing institute of Atmospheric physics Chinese Academy of Sciences Beijing 100029 China Graduate University of the chinese academy of sciences Beijing 100049 China

We have established a regional air-sea coupled model over East Asia and conducted a 2.-year integration to evaluate its performance in reproducing the present *** coupled model consists of RegCM3.and HYCOM controlled by the OASIS3.coupler with resuolution of 60 km for the atmosphere and 3. km for the ocean,*** some other regional air-sea coupled models,a one-way nesting method is employed in the oceanic component and a heat flux adjustment for solar radiation is used to remove an about 2.C cold bias in *** primary analysis for this 2.-year integration shows that the coupled model successfully reproduces the main features of the circulations over East Asia,both in the atmosphere and the ocean,including climatology,seasonal and interannual *** are seen in the coupled model compared to the uncoupled one,especially in the simulation of precipitation,the most important element of the East Asian monsoon,although there are still obvious discrepancies that come mainly from the model components *** analyses show that the rainfall simulation benefits from the enhancements of the Northwest Pacific Subtropical high in summer,which leads to the improvement of the moisture flux simula-tion at the middle-lower atmospheric *** results indicate that the regional air-sea coupled model is more suitable for the East Asia monsoon simulation.

关键词：海气耦合模式东亚地区空气西北太平洋副高大气环流海域耦合模型模拟降雨

In situ study on dendrite growth of metallic alloy by a synchrotron radiation imaging technology

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science china(Technological sciences) 2010年第5期53卷 1278-1284页

作者： WANG TongMin1,XU JingJing1,LI Jun1,HUANG WanXia2.LIU ShengChu1 & LI TingJu1 1 School of Materials science and Engineering,Dalian University of Technology,Dalian 11602.,{3. 2.{2. of high Energy physics,chinese academy of sciences,beijing 10003.,{3. 1. School of Materials science and Engineering Dalian University of Technology Dalian 116024 China2. Institute of High Energy Physics Chinese Academy of Sciences Beijing 100039 China

This study was trying to observe the real-time dendrite growth of Sn-Bi and Sn-Pb binary alloys by a synchrotron radiation imaging *** imaging system includes an intense and {2. brightness synchrotron radiation source,a {2.-resolution and fast-readout charge coupled device camera,an alloy sample and a Bridgman solidification *** imaging experiments were done at beijing synchrotron radiation Facility with an updated synchrotron radiation imaging technique,diffraction-enhanced imaging,which was firstly used to study the dendrite growth of metallic alloy.A series of growth behavior and morphology evolution of dendrite have been in situ observed,such as columnar-to-equiaxed transition,dendrite competition,dendrite fragmentation and floating,etc.,which can offer the direct proofs to verify or improve the solidification theories of metallic *** research opens a novel window for the study of alloy solidification and enables the unambiguous understanding of solidification processes in optically opaque,metallic alloys.

关键词： dendritic growth synchrotron radiation solidification diffraction-enhanced imaging metal and alloys

The time lag spectrum of Cir X-1 on its normal branch

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science china({2.,Mechanics & Astronomy) 2010年第S1期53卷 60-63页

作者： QU JinLu1,LU Yu1,2.DING GuoQiang3.ZHANG Fan1,LEI YaJuan1 & LI ZhiBing1 1 Key laboratory for Particle Astrophysics,{2. of high Energy physics,chinese academy of sciences,beijing 100049,china 2.Graduate University of chinese academy of sciences,beijing 100049,china 3.Urumqi Observatory,NAOC Urumqi 83.011,china 1. Key laboratory for Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China3. Urumqi Observatory NAOC Urumqi 830011 China

In the radiation-hydrodynamics model,the time lag and fractional root-mean-squared(rms) amplitude as a function of emitted photon energy should show a minimum on the normal branch *** has been seen in the Z-sources Cyg X-2.and GX ***,using the observations from the Rossi X-ray Timing Explorer(RXTE),we study the energy dependence of normal branch QPOs in the peculiar Z-source Cir *** discuss the results in the context of radiation-hydrodynamics and the Comptonization model.

关键词： Cir X-1 temporal variability QPO time lag

EXAFS study on arsenic species and transformation in arsenic hyperaccumulator

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science china(Life sciences) 2004年第2期47卷 124-129页

作者： HUANG Zechun1, CHEN Tongbin1, LEI Mei1, HU Tiandou2.& HUANG Qifei1 1. laboratory of Environmental Remediation, institute of Geographical {2.s and Natural Resources Research, chinese academy of {2.s, beijing 100101, china 2. laboratory of synchrotron radiation, institute of {12. Energy physics, chinese academy of {2.s, beijing 10003., china Correspondence should be addressed to Chen Tongbin 1. laboratory of Environmental Remediation Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences 100101 Beijing China 2. Plaboratory of synchrotron {2. Institute of High Energy Physics Chinese Academy of Sciences 100039 Beijing China

synchrotron radiation extended X-ray absorption fine structure (SR EXAFS) was employed to study the transformation of coordination environment and the redox speciation of arsenic in a newly discovered arsenic hyperaccumulator, Cretan brake (Pteris cretica L. var ner-vosa Thunb). It showed that the arsenic in the plant mainly coordinated with oxygen, except that some arsenic coordinated with S as As-GSH in root. The complexation of arsenic with GSH might not be the predominant detoxification mechanism in Cretan brake. Although some arsenic in root presented as As(V) in Na2.AsO4 treatments, most of arsenic in plant presented as As(III)-O in both treatments, indicating that As(V) tended to be reduced to As(III) after it was taken up into the root, and arsenic was kept as As(III) when it was transported to the above-ground tissues. The reduction of As(V) primarily proceeded in the root.

关键词： hyperaccumulator, Cretan brake (Pteris cretica L. var nervosa Thunb), arsenic, species, EXAFS.

Penetrating view of nano-structures in Aleochara verna spermatheca and flagellum by hard X-ray microscopy

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chinese physics B 2013年第7期22卷 410-414页

作者：张凯李德娥洪友丽朱佩平袁清习黄万霞高昆周红章吴自玉 institute of high Energy {2.h Chinese Academy of Sciences Key laboratory of Zoological Systematics and Evolution Institute of ZoologyChinese Academy of Sciences National synchrotron radiation {2. University of Science and Technology of China

A penetrating view of the three-dimensional nanostructure of female spermatheca and male flagellum in the species Aleochara verna is obtained with 100-nm resolution using a hard X-ray microscope, which provides a fast noninvasive imaging technology for insect morphology. Through introducing Zernike phase contrast and heavy metal staining, images taken at 8 keV displayed sufficient contrast for observing nanoscale fine structures, such as the spermatheca cochleate duct and the subapex of the flagellum, which have some implications for the study of the sperm transfer process and genital evolution in insects. This work shows that both the spatial resolution and the contrast characteristic of hard X-ray microscopy are quite promising for insect morphology studies and, particularly, provide an attractive alternative to the destructive techniques used for investigating internal soft tissues.

关键词： X-ray microscopy computed tomography synchrotron radiation source morphology