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An　Information　Theory　Approach　to　the　Data　Compression　and　Imaging　System　for　Synthetic　Aperture　Radar　（SAR）

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Journal of Systems engineering and Electronics 1995年第1期6卷 1-15页

作者： Xiao Yongxin Peng Hailiang and Chen Zongzhi(institute of Electronics, chinese academy of sciences, beijing 100080, P. R. china.) institute of Electronics Chinese Academy of Sciences Beijing 100080 P. R. China

Synthetic aperture radar (SAR) is portrayed as a multiple access channel. An information theory approach is applied to the SAR imaging system, and the information content about a target that can be extracted from its radar image is evaluated by the average mutual information measure. A conditional (transition) probability density function (PDF) of the SAR imaging system is derived by analyzing the system and a closed form of the information content is found. It is shown that the information content obtained by the SAR imaging system from an independent sample of echoes will decrease and the total information content obtained by the SAR imaging system will increase with an increase in the number of looks. Because the total average mutual information is also used to define a measure of radiometric resolution for radar images, it is shown that the radiometric resolution of a radar image of terrain will be improved by spatial averaging. In addition, the imaging process and the data compression process for SAR are each treated as an independent generalized communication channel. The effects of data compression upon radiometric resolution for SAR are studied and some conclusions are obtained.

关键词： Synthetic aperture radar (SAR) information theory data compression radiometric resolution,probability density function (PDF) multiple access channel average mutual information

Variations of near-surface atmospheric CO_(2)and H_(2)O concentrations during summer on Muztagata

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Science china Earth sciences 2006年第1期49卷 18-26页

作者： XU Baiqing1,2, YAO Tandong1,2, LU Anxin2, GUO Xuejun, LIU Xianqin2 & LI Zhen2 1. Laboratory of Environment and process on Tibetan Plateau, institute of Tibetan Plateau Research, chinese academy of sciences, beijing 100085, china 2. Key Laboratory of Cryosphere and Environment, Jointly Established by Cold and Arid Regions Environmental and Engi-neering Research institute and institute of Tibetan Plateau Research, chinese academy of sciences and chinese academy of Meteorological sciences, china Meteorological Administration, Lanzhou 730000, china Laboratory of Environment and process on Tibetan Plateau Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing China Key Laboratory of Cryosphere and Environment Jointly Established by Cold and Arid Regions Environmental and Engineering Research Institute and Institute of Tibetan Plateau Research Chinese Academy of Sciences and Chinese Academy of Meteorological Sciences China Meteorological Administration Lanzhou China

Expeditions during the summers of 2002 and 2003 implemented continuous monitoring of near-surface (2 m height) atmospheric CO2 and H2O concentrations at the 4500 m elevation on Muztagata. The resultant data sets reveal a slight decrease of CO2 concentrations (of about 5 μmol·mol?1) and changes in the diurnal variations from the end of June to the middle August. The daily maximum CO2 concentrations occur between 02:30―05:30 AM (local time) and the minimum levels occur between 12:00―15:30 PM. The atmospheric CO2 concentrations in the summer of 2002 were around 5 μmol·mol?1 lower than those during the same period of 2003, whereas the diurnal amplitude was higher. In contrast, we found that the daily mean atmospheric H2O content in 2003 was much lower than that in 2002 and there exists a striking negative correlation between CO2 and H2O con-centrations. We therefore suggest that the near-surface atmospheric CO2 concentration is affected not only by photosynthesis and respiration, but also by the air H2O content in the glaciated region around Muztagata.

关键词： atmospheric CO2 and H2O concentration, continuous monitoring, glaciation region, Muztagata.

A NOTE ON FIRST PASSAGE TIMES FOR GI/M/1 TYPE MARKOV processES

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中国科学院大学学报(中英文) 1994年第1期 1-10页

作者： Xue-Ming Yuan(institute of Automation, chinese academy of sciences, beijing, 100080)

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关键词： GI/M/1 type Markov process first passage time L-S transform vector

Transgenic expression of DwMYB2 impairs iron transport from root to shoot in Arabidopsis thaliana

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Cell Research 2006年第10期16卷 830-840页

作者： Yan-Hong Chen~(1,2,3) Xue-Min Wu~5 Hong-Qing Ling~4 Wei-Cai Yang~1 ~1The Key Laboratory of Molecular and Developmental Biology,institute of Genetics and Developmental Biology,chinese academy of sciences,beijing 100101 china ~2Graduate University of the chinese academy of sciences,19 Yuquan Road,beijing 100049,china ~3School of Life Science,Nantong University,Nantong 226007 china ~4The State Key Laboratory of Plant Cell and Chromosome engineering,institute of Genetics and Developmental Biology,chinese academy of sciences,beijing 100101,china The Key Laboratory of Molecular and Developmental Biology Institute of Genetics and Developmental Biology Chinese Academy of Sciences Beijing China Graduate University of the chinese academy of sciences Beijing China School of Life Science Nantong University Nantong China Department of Botany University of British Columbia 6270 University Blvd. Vancouver Canada The State Key Laboratory of Plant Cell and Chromosome engineering Institute of Genetics and Developmental Biology Chinese Academy of Sciences Beijing China

In plant,iron uptake and homeostasis are tightly regulated to ensure its absorption from soil and to avoid excessiron in the *** genes involved in this process have been identified during past several years,but there are manyproblems remain unsolved in the genetic regulation of whole plant iron trafficking and *** transcriptionfactors contain tandem repeats of a～50 amino acid DNA-binding motif (R) and are involved in the regulation of manyaspects of plant development,hormone signaling and ***,we report that the ectopic expression of orchidR2R3-MYB gene DwMYB2 in Arabidopsis thaliana confers the transgenic plants hypersensitivity to iron *** DwMYB2 transgenic plants,the iron content in root is two-fold higher compared to that in wild-type root,while thereverse is true in *** imbalance of iron content in root and shoot suggested that the translocation of iron fromroot to shoot was affected by the expression of DwMYB2 in the transgenic ***,gene chip and reversetranscription-polymerase chain reaction analysis revealed that the ferric-chelate reductase gene,AtFRO2,and the irontransporter gene,AtIRT1 and AtIRT2,are up-regulated by DwMYB2 expression,while other potential iron transporterssuch as AtIREG1,AtFRD3 and NRAMP1 are *** addition,the expression of several putative peptidetransporters and transcription factors are also altered in the 35S::DwMYB2 transgenic *** data provide us insightinto the whole plant translocation of iron and identify candidate genes for iron homeostasis in plants despite the fact thata heterologous gene was expressed.

关键词： DwMYB2 iron uptake and homeostasis iron transporters Arabidopsis

EFFECT OF PARTICLE SIZE ON THE FILMING process OF POLYSTYRENE LATEX STUDIED BY AFM

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chinese Journal of Polymer Science 2002年第6期20卷 509-515页

作者： Xiao-zhong Qu Yi Shi Liu-sheng Chen Xi-gao Jin State Key Laboratory of Polymer Physics & Chemistry, Center for Molecular Science,institute of Chemistry, chinese academy of sciences, beijing 100080 china State Key Lab. of Polymer Phy./Chem. Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China

The film formation process of micro-PS particles (diameter 742 nm) and nano-PS particles (diameter 29 nm) was studied by atomic force microscopy and differential scanning calorimetry. During a step heating process, the particles were annealed for 0.5 h at each selected temperature. It was found that the deformation and interdiffusion temperatures of the micro-PS particles are ca. 120-130degreesC and 140-150degreesC, that of the nano-PS particles are 90degreesC and 100-110degreesC respectively. The DSC traces of nano-PS particles showed that there was an exothermic peak near T-g after annealing for 0.5 h at the selected temperatures below 90degreesC; otherwise, the exothermic peak disappeared after annealing at 100degreesC or above. Compared with the micro-PS particles, the sintering process of nano-PS particles occurs at much lower temperature determined by the confined state of polymer chains with higher conformational energy in nano-particles, and completes in a much narrower temperature range driven mainly by the larger total surface energy.

关键词： polystyrene latex filming process particle size effect

Dynamic behaviors of cavitation bubble for the steady cavitating flow

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Journal of Thermal Science 2009年第4期18卷 338-344页

作者： Jun CAI,Xiulan HUAI and Xunfeng LIinstitute of engineering Thermophysics,chinese academy of sciences,P.O.Box 2706,beijing 100190,china Professor institute of engineering Thermophysics Chinese Academy of Sciences Beijing China

In this paper, by introducing the flow velocity item into the classical Rayleigh-Plesset dynamic equation, a newequation, which does not involve the time term and can describe the motion of cavitation bubble in the steadycavitating flow, has been obtained. By solving the new motion equation using Runge-Kutta fourth order methodwith adaptive step size control, the dynamic behaviors of cavitation bubble driven by the varying pressure fielddownstream of a venturi cavitation reactor are numerically simulated. The effects of liquid temperature (correspondingto the saturated vapor pressure of liquid), cavitation number and inlet pressure of venturi on radial motionof bubble and pressure pulse due to the radial motion are analyzed and discussed in detail. Some dynamicbehaviors of bubble different from those in previous papers are displayed. In addition, the internal relationshipbetween bubble dynamics and process intensification is also discussed. The simulation results reported in thiswork reveal the variation laws of cavitation intensity with the flow conditions of liquid, and will lay a foundationfor the practical application of hydrodynamic cavitation technology.

关键词： cavitation bubble bubble dynamics hydrodynamic cavitation cavitating flow process intensification

Energy Transfer among Chlorophylls in Trimeric Light-harvesting Complex Ⅱ of Bryopsis corticulans

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Acta Biochimica et Biophysica Sinica 2006年第5期38卷 310-317页

作者： Su-Juan ZHANG~(1,2*)Shui-Cai WANG~2 Jun-Fang HE~2 Hui CHEN~3 1 institute of Photonics and Photo-Technology,Northwest University,Xi'an 710069,china 2 State Key Laboratory of Transient Optics and Photonics,Xi 'an institute of Optics and Precision Mechanics,chinese academy of sciences,Xi'an 710068.china 3 Laboratoty of Photosynthesis Basic Research,institute of Botany,chinese academy of sciences,beijing 100093,china institute of Photonics and Photo-Technology Northwest UniversityXi'an 710069 China State Key Laboratory of Transient Optics and Photonics Xi'an Institute of Optics and Precision Mechanics Chinese Academy of SciencesXi'an 710068 China Laboratory of Photosynthesis Basic Research Institute of Botany Chinese Academy of SciencesBeijing 100093 China

A study on energy transfer among chlorophylls（Chls）in the trimeric unit of the major light-harvesting complex Ⅱ（LHC Ⅱ）from Bryopsis corriculan,was carried out using time-correlated singlephoton *** the chlorophyll Q region of LHC Ⅱ,six molecules characterized as Chlb628,Chlb646,Chlb652654,657,Chla664666,Chla674677.680and Chla682683were discriminated according to their absorption spectrumand fluorescence emission ***,excited by pulsed light of 628 nm,fluorescence kinetics spectrain the chlorophyll Q region were *** accordance with the principles of fluorescence kinetics,thesekinetics data were analyzed with a multi-exponential *** constants on energy transfer were *** overwhelming percentage of energy transfer among chlorophylls undergoes a process longer than 97picoseconds（ps）,which shows that,before transferring energy to another Chl,the excited Chl might convertenergy to vibrations of a lower state with different multiplicity（intersystem crossing）.Energy transfer at thelevel of approximately 10 ps was also obtained,which was interpreted as the excited Chls may go throughinternal conversion before transferring energy to another *** with a higher standard deviation,timeconstants at the femtosecond level can not be entirely excluded,which can be attributed to the ultrafastprocess of direct energy *** to the arrangement and direction of the dipole moment of Chls inLHC Ⅱ,the probability of these processes is *** fluorescence lifetimes of Chlb652654,657,Chla664666,Chla674677.680and Chla682683were determined to be 1.44ns,1.43 ns,636 ps and 713 ps,*** of energy dissipation in the pathway of fluorescence emission were no more than 40% in thetrimeric unit of LHC Ⅱ.These results are important for a better understanding of the relationship between thestructure and function of LHC Ⅱ.

关键词： energy transfer LHC Ⅱ transient spectrum fluorescence kinetics

ANALYSIS OF A PRODUCTION-INVENTORY MODEL WITH ERLANGIAN DEMAND ARRIVAL process

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Journal of Systems Science & Complexity 2003年第2期16卷 184-190页

作者： WANG Jinting CAO Jinhua LIU Bin(institute of Applied Mathematics, academy of Mathematics and Systems sciences, chinese academy of sciences, beijing 100080, china) institute of Applied Mathematics Academy of Mathematics and Systems Sciences Chinese Academy of Sciences 北京 100080

We study a production-inventory system having a machine, a storage facility. The demand for the product is governed by an Erlangian demand arrival process, where demand sizes are independent and identically distributed random variables. A two-criticalnumber policy (m, M) is used to control a machine's setups and shutdowns, namely, a machine is shut down whenever the inventory level reaches M, and resumes operating only when the inventory level falls below the critical number m(m ≤ M). We obtain the steady state distribution of the inventory process and some performance measures of the process.

关键词： erlangian demand arrival process production-inventory system

Photosynthesis for Food,Fuel and the Future

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Journal of Integrative Plant Biology 2010年第8期52卷 I0001-I0001,695-697页

作者： Congming Lu institute of Botany chinese academy of sciences china Issue Editorinstitute of Botanychinese academy of scienceschina

Photosynthesis is a process that converts solar energy to chemical energy in many different organisms, ranging from plants to bacteria. Photosynthesis provides all the food we eat and all the fossil fuel we use. Photosynthesis has long been studied in order to understand its underlying mechanisms and then to apply this knowledge to the production of energy and food for the needs of our society. The 15th International Congress on Photosynthesis will be held in beijing from August 22 to 27, 2010. It will feature eminent plenary speakers and state-of-the-art symposium speakers who are at the cutting edge of discovery in their fields and provide an exciting scientific program which will cover the breadth and depth of photosynthesis from molecular to global. To celebrate this congress, Journal of Integrative Plant Biology （JIPB） publishes a special issue on photosynthesis which includes reviews of the recent progress on the various aspects of photosynthesis.

关键词： Photosynthesis for Food,Fuel and the Future OEC