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Thermal analysis of the baffle structure of the Solar Space Telescope

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Science china(Physics,Mechanics & Astronomy) 2010年第9期53卷 1755-1764页

作者： LI Rong1,2.3.& WANG Sen1,3.1 National Astronomical Observatories,chinese Academy of sciences,{2. 100012.china 2.graduate University of chinese Academy of sciences,{2. 100049,china 3.Key Laboratory of Solar Activity,National Astronomical Observatories of chinese Academy of sciences,{2. 100012.china 1. National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China3. Key Laboratory of Solar Activity National Astronomical Observatories of Chinese Academy of Sciences Beijing 100012 China

The SST(Space Solar Telescope) is an astronomical telescope with a primary mirror of 1 m in *** observes the sun with a small view field to ensure that its high spatial resolution imaging has 0.1″-0.15″ and high SNR(signal to noise ratio).Surrounding the small view field is still the sun,which is an intense source of both heat and stray *** baffles(the main baffle,the aperture,and the outer baffle),which are used to eliminate the stray light,will change the thermal flux in the SST and will weaken the effect of the thermal control *** this study,the compatibility analysis of the thermal effect of baffle structures in SST is *** GCF(Geometry Composing Function) and BRDF(Bidirectional Reflectance Distribution Function),which are two inherent related parameters in the compatibility analysis,are *** objective and method of the compatibility analysis are *** the thermal analysis software,the temperature fields are calculated for different lengths of the main baffle,different radii of apertures,different lengths of the outer baffle with a 3. tilt angle and 16' tilt angle,and different tilt angles of the outer baffle with a 2.0 mm length.A series of configurations and sizes of the baffles are studied with the goals of both thermal control and elimination of stray *** design of the baffle structure of SST is achieved:the main baffle of length 4100 mm,the internal shield of radius 494 mm,the outer baffle of length 2.0 mm,and the outer baffle of tilt angle 3. are successfully *** paper presents the relationship between the thermal control design and stray light elimination plan in the *** aims of the optimal design of the baffle structure of SST are *** thoughts and methods of the optimal analysis are also useful for similar optical telescopes designed for solar observation.

关键词： baffle the main baffle the outer baffle GCF BRDF

Study on growth and properties of novel γ-LiAlO_2.substrate

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Science china(Technological sciences) 2006年第2期49卷 188-193页

作者： ZOU Jun1,2. ZHOU Shengming1, XU Jun1 & ZHANG Rong3.1. Shanghai Institute of Optics and Fine Mechanics, chinese Academy of sciences, Shanghai 2.1800,{2. 2. graduate school of chinese Academy of sciences, beijing 10003.,{2. 3. Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 2.0093.{2. 1. Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800 China 2. graduate school of {2. Academy of sciences Beijing 100039 China 3. Laboratory of Solid State Microstructures and Department of Physics Nanjing University Nanjing 210093 China

Transparent γ-LiAlO2.single crystal has been grown by Temperature Gradient technique. The surface of the wafer annealed in O2.atmosphere at 1100°C for 70 h became opaque and Li-poor phase (LiAl5O8); while, that annealed in Li-rich atmosphere kept transparent and smooth. The full-width at half maximum value dropped to 3. arcsecs when the wafer was annealed in Li-rich atmosphere. That annealed in O2.atmosphere increased to 78 arcsec. Compared with absorption spectra, we can conclude that the 196 nm absorption peak was caused by Li vacancies and the 73. nm peak was caused by O vacancies.

关键词： γ-LiAlO2 crystal, scanning electron micrograph (SEM), absorption spectra.

Land cover changes based on plant successions: Deforestation, rehabilitation and degeneration of forest in the upper Dadu River watershed

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Science china Earth sciences 2005年第12期48卷 2214-2230页

作者： YAN Jianzhong1,2.3. ZHANG Yili1, BAI Wanqi1, LIU Yanhua4, BAO Weikai5, LIU Linshan1, 2.& ZHENG Du1 1. Institute of Geographic sciences and Natural Resources Research, {3. Academy of sciences, beijing 100101, china 2. graduate school of the {3. Academy of sciences, beijing 10003., china 3. College of Resources and Environment, Southwest Agricultural University, Chongqing 400716, china 4. The Ministry of Science and Technology, P. C. china, beijing 100862. china 5. Chengdu Institute of Biology, {3. Academy of sciences, Chengdu 610041, china 1. Institute of Geographic sciences and Natural Resources Research Chinese Academy of Sciences 100101 Beijing China 2. graduate school of the {2. Academy of sciences 100039 Beijing China 3. College of Resources and Environment Southwest Agricultural University 400716 Chongqing China 4. The Ministry of Science and Technology P. C. China 100862 Beijing China 5. Chengdu Institute of Biology Chinese Academy of Sciences 610041 Chengdu China

To link regional land use/cover changes with environmental effects, land cover changes are required to reflect vegetation successions, whereas the land cover classification systems commonly used nowadays cannot serve this purpose. In this paper, a new land cover classification system is established in which land covers are classified by the vegetation succes-sions, taking Zamtang County, Barkam County and Jinchuan County in the upper Dadu River watershed as a study area. Using multi-temporal remote sensing images, the land cover data of 1967, 1986 and 2.00 are obtained by means of integration of unsupervised classification and visual interpretation methods. The database facilitates the study of land use/cover changes, en-vironmental effects and ecological construction. Land cover changes reflect the main ecological processes in the upper Dadu River watershed. The landscape composed mainly of grasslands, wildwoods and alpine scrubs in 1967 was changed to that of grasslands, secondary forests, al-pine scrubs, fragmentary wildwoods, artificial forests, secondary scrubs in 2.00, meanwhile, the landscape got more fragmentized. The total area of the forests decreased by 9.43.. Study results have shown the process of restoration of logged areas in forest centers. From 1967 to 2.00, only 6.86 percents of logged areas were converted to shrubs, meadows or crop-lands, and the rest were converted into artificial forests or secondary forests. So the ecological shelter functions will be restored, stage by stage. Firewood collection, charcoal production and overgrazing are the three major triggers for the extensive degradation of alpine oak forests, Sa-bina tibetica forests and meadows. The arid valley grasslands expanded too. The degradation of vegetation in the southern slopes impairs ecological shelter functions and affects livelihood of local residents, so it is essential to find effective measures for ecological restoration and recon-struction. Field investigations have found

关键词： land use/cover classification, upper Dadu River watershed, vegetation successions, GIS, RS.

Effects of cosmological constant on motion of UHECR particles

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Science china(Physics,Mechanics & Astronomy) 2005年第1期48卷 44-56页

作者： CHEN Shaoxia & CHANG Zhe Institute of High Energy Physics, chinese Academy of sciences,{2.,{3. graduate school of chinese Academy of sciences,{2.,{3. Institute of High Energy Physics Chinese Academy of Sciences Beijing 100039 China graduate school Chinese Academy of Sciences Beijing 100039 China

Recent astronomical observations manifest that about two-thirds of the whole energy in the Universe is contributed by a small positive cosmological constant A (> 0). Then, an asymptotically de Sitter spacetime is premised naturally. However, physics in the de Sitter spacetime is very different from that in the Minkowski spacetime. As the first step, a covariant formalism of the kinematics in the de Sitter spacetime is presented here. By solving exactly the equations of motion for a field, we obtain the dispersion relation of a free particle. It is noticed that the dispersion relation is dependent on the degree of freedom of angular momentum of the particle. We show the threshold anomaly of the ultra high energy cosmic ray disappears naturally in the framework of the de Sitter kinematics.

关键词： ultrahigh energy cosmic ray, cosmological constant, curved spacetime.

A 12.bit multichannel ADC for pixel detectors in particle physics and nuclear imaging

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Science china(Technological sciences) 2010年第5期53卷 1208-1214页

作者： WEI Wei1,2.3.WANG Zheng1,3.& ZHAO JingWei1,3.1 Institute of High Energy Physics,chinese Academy of sciences,{2. 100049,china 2.graduate University of chinese Academy of sciences,{2. 100049,china 3.Key Lab of Nuclear Detection Technology and Nuclear Electronics of chinese Academy of sciences,{2. 100049,china 1. Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China3. Key Lab of Nuclear Detection Technology and Nuclear Electronics of Chinese Academy of Sciences Beijing 100049 China

Modern pixel detectors in nuclear and particle physics experiments and also in nuclear imaging,starve for highly integrated application specified integrated circuit(ASIC),whereas in china the study of ASIC still stays far away from practical *** lack of ASIC strictly limits the research and development of domestic high energy physics field.A 12.bit multichannel ADC designed for high density readout is introduced as a major candidate for solution.A precise model is discussed and the simulation fully agrees with the model,which indicates a key principle of *** is performed according to the given rule,and novel layout techniques are carried *** results in all aspects are also obtained,showing an excellent real performance,which satisfies the practical requirement.

关键词： application specified integrated circuit high density readout Wilkinson ADC multi-channel ADC

Transformations and non-degenerate maps

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Science china Mathematics 2005年第z1期48卷 195-205页

作者： LI Baokui & WANG Yuefei Institute of Mathematics, Academy of Mathematics and System sciences, chinese Academy of sciences, {3. 100080, china graduate school, chinese Academy of sciences, {3. 100080, china 1. Institute of Mathematics Academy of Mathematics and System Sciences Chinese Academy of Sciences 100080 Beijing China 2. graduate school Chinese Academy of Sciences 100080 Beijing China

We shall prove the equivalences of a non-degenerate circle-preserving map and a M(o)bius transformation in ^Rn, of a non-degenerate geodesic-preserving map and an isometry in Hn of a non-degenerate line-preserving map and an affine transformation in Rn. That a map is non-degenerate means that the image of the whole space under the map is not a circle, or geodesic or line respectively. These results hold without either injective or surjective, or even continuous assumptions, which are new and of a fundamental nature in geometry.

关键词： M(o)bius transformation, circle-preserving map, non-degenerate map.

Recent advances in the data analysis method of functional magnetic resonance imaging and its applications in neuroimaging

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Progress in Natural Science:Materials International 2006年第8期16卷 785-795页

作者： TIAN Jie, YANG Lei and HU Jin (Institute of Automation, chinese Academy of sciences, {2. 100080,{3. graduate school of chinese Academy of sciences, beijing 10003.,{3.) [a]chinese Academy of sciences Institute of Automation Beijing China [b]graduate school of {2. Academy of {3. Beijing China

Functional magnetic resonance imaging (fMRI) has opened a new area to explore the human brain. The fMRI can reveal the deep insights of spatial and temporal changes underlying a broad range of brain function, such as motor, vision, memory and emotion, all of which are helpful in the clinical investigation. In this paper, we introduce some recent-developed algorithms for fMRI signal detection such as model-driven method (general linear model, deconvolution model, non-linear model, etc. ) and data-driven method (principle component analysis, independent component analysis, self-organization mapping, clustered constrained non-negative matrix factorization, etc. ). We also propose several important applications of neuroimaging and point out their shortcomings and future perspectives.

关键词： fMR1 data analysis neuroimaging.

A cumulant-based parameter estimation algorithm for near-field sources

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Progress in Natural Science:Materials International 2007年第8期17卷 900-905页

作者： Liang Junli~(1,2.) Yang Shuyuan~(1,2. Zhang Junying~3.(1.Institute of Acoustics,chinese Academy of {3.,{2. 100080,china 2.graduate school,chinese Academy of {3.,{2. 10003.,china 3.National Laboratory of Radar Signal Processing,Xidian University,Xi'an 710071,china) [a]Institute of Acoustics Chinese Academy of Sciences Beijing China [b]graduate school Chinese Academy of Sciences Beijing China [c]National Laboratary of Radar Signal Processing Xidian University Xi'an China

To efficiently use the array aperture and avoid the complicated parameter pairing computation,this paper proposes a new cumulant-based algorithm for localizing near-field narrowband ***,this algorithm proposes a symmetric uniform linear ar- ray (ULA),and constructs three cumulant matrices by using the fourth-order cumulants of some properly chosen sensor outputs;second- ly,unlike the conventional parallel factor (PARAFAC) analysis models in data or subspace domain,it forms a three-way array (TWA) in the fourth-order cumulant domain using the three matrices,and analyzes the uniqueness of its low-rank decomposition;thirdly,it jointly estimates the frequency,the direction-of-arrival (DOA),and the range of each near-field source from the matrices via the low-rank de- composition of the *** simulation results are presented to validate the performance of our proposed method.

关键词： array signal processing localization cumulant parallel factor (PARAFAC) analysis three-way array (TWA)

A subsurface runoff parameterization with water storage and recharge based on the Boussinesq-Storage Equation for a Land Surface Model

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Science china Earth sciences 2006年第6期49卷 622-631页

作者： TIAN Xiangjun1,2. XIE Zhenghui1, ZHANG Shenglei1 & LIANG Miaoling1 1. LASG, Institute of Atmospheric Physics, chinese Academy of sciences, {2. 10002., china 2. graduate school of the chinese Academy of sciences, beijing 10003., china 1. LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China 2. graduate school of the {2. Academy of sciences Beijing 100039 China

Subsurface runoff in a land surface model is usually parameterized as a single-valued function of total storage in a basin aquifer reservoir. This kind of parameterization is often sin-gle-valued function of storage-discharge under a steady or “quasi-steady” state, which cannot rep-resent the influence of aquifer recharge on subsurface runoff generation. In this paper, a new sub-surface runoff parameterization with water storage and recharge based on the Boussinesq-storage equation is developed. This model is validated by a subsurface flow separation algorithm for an ex-ample river basin, which shows that the new model can simulate the subsurface flow reasonably.

关键词： Zsubsurface runoff parameterization Boussinesq-storage equation waterstorage and recharge