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Quantitative estimation of the shrub canopy LAI from atmosphere-corrected HJ-1 CCD data in Mu Us Sandland

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Science China Earth sciences 2010年第S1期53卷 26-33页

作者： CHEN Wei1,2,CAO ChunXiang1,HE QiSheng1,2,GUO HuaDong3,ZHANG Hao1,2,LI RenQiang4,ZHENG Sheng1,2,xu Min1,2,GAO Mengxu1,2,ZHAO Jian1,2,LI Sha1,NI XiLiang1,2,JIA HuiCong1,JI Wei1,TIAN Rong1,2,LIU Cheng1,2,ZHAO YuXing5.& LI JingLu6 1 State Key Laboratory of Remote Sensing Science,Jointly Sponsored by the institute of Remote Sensing Applications of chinese academy of sciences and beijing Normal University,beijing 100101,China 2 Graduate University of chinese academy of sciences,beijing 100049,China 3 Center for Earth Observation and Digital Earth,chinese academy of sciences,beijing 100190,China 4 China Key Laboratory of Ecological Network Observation and Modeling,institute of Geographical sciences and Natural Resources Research,chinese academy of sciences,beijing 100101,China 5.Ordos Forestry Sand Control Science institute,Dongsheng 017000,China 6 Inner Mongolia Biomass Thermoelectricity Limited Company,Wushen 017300,China 1. State Key Laboratory of Remote Sensing Science Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Beijing 100101 China 2. Graduate University of chinese academy of sciences Beijing 100049 China 3. Center for Earth Observation and Digital Earth Chinese Academy of Sciences Beijing 100190 China 4. China Key Laboratory of Ecological Network Observation and Modeling Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China 5. Ordos Forestry Sand Control Science institute Dongsheng 017000 China 6. Inner Mongolia Biomass Thermoelectricity Limited Company Wushen 017300 China

The leaf area index(LAI) is an important ecological parameter that characterizes the interface between vegetation canopy and the *** addition,it is used by most process-oriented ecosystem *** paper investigates the potential of HJ-1 CCD data combined with linear spectral unmixing and an inverted geometric-optical model for the retrieval of the shrub LAI in Wushen Banner of Inner Mongolia in the Mu Us ***(Moderate Resolution Atmospheric Radiance and Transmittance Model) was used for atmospheric *** was extracted using the threshold of the normalized difference vegetation index,with which water bodies and farmland were separated,in combination with a vegetation map of the People's Republic of China(1:1000000).Using the geometric-optical model,we derive the per-pixel reflectance as a simple linear combination of two components,namely sunlit background and *** fraction of sunlit background is related to the shrub *** the support of HJ-1 CCD data,we employ linear spectral unmixing to obtain the fraction of sunlit background in an atmospherically corrected HJ *** addition,we use the measured shrub canopy structural parameters for shrub communities to invert the geometric-optical model and retrieve the pixel-based shrub *** total,18 sample plots collected in Wushen Banner of Inner Mongolia are used for *** results of the shrub LAI show good agreement with R2 of 0.817 and a root-mean-squared error of 0.173.

关键词： shrub leaf area index inversion HJ-1 data geometric-optical model MODTRAN Mu Us Sandland

Low-temperature magnetic properties of horse spleen ferritin

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chinese Science Bulletin 2010年第27期55卷 3174-3180页

作者： TIAN LanXiang 1,2,CAO ChangQian 1,2,LIU QingSong 1,2 &PAN YongXin 1,2 1Key Laboratory of the Earth’s Deep Interior,institute of geology and geophysics,chinese academy of {5.,beijing 1.0029,China 2Franco-chinese Biomineralization and Nano-structures Laboratory,beijing 1.0029,China Key Laboratory of the Earth''s Deep Interior Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Franco-chinese Biomineralization and Nano-structures Laboratory Beijing 100029 China

The magnetic properties of the antiferromagnetic cores in ferritin are of importance in the construction and improvement of ferritin-based magnetic resonance imaging systems and their application to environmental *** this study,we carry out integrated magnetic and transmission electron microscopy analyses of horse spleen ferritin(HoSF)to understand the relationships between the magnetic behavior of HoSF and temperature,applied field and grain-size *** R-value from the Wohlfarth-Cisowski test for the investigated sample at 5.K was 0.46,indicating very weak magnetostatic interactions among the nanoparticles of *** nanoparticles of HoSF show superparamagnetic properties at room temperature,while below the blocking temperature of Tb≈12 K it has a net magnetic moment that comes from the uncompensated spins of the nanoparticle surface or *** thermal relaxation process of HoSF follows the Néel-Arrhenius *** low-temperature AC susceptibility data,we calculated the effective magnetic anisotropy energy Ea=(5.5.±0.16)×10-21 J;the effective magnetic anisotropy energy constant Keff=(4.65.0.14)×10 4 J/m3 and the pre-exponential frequency factor f0 =(4.5.±2.93)×1011 *** values are useful in understanding the magnetic behavior of the antiferromagnetic nanoparticles and their potential application in biomedical technology.

关键词：马脾铁蛋白低温度磁性质透射电子显微镜磁各向异性常数纳米粒子生物医学技术交流磁化率

中国大陆地壳“镶嵌与叠覆”的结构特征及其演化

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地质通报 2004年第9期23卷 986-1004页

作者： LI Jinyi(institute of geology, chinese academy of Geological sciences, {5. 100037, China) 中国地质科学院地质研究所北京100037

初步探讨了中国大陆地壳“块带镶嵌多层叠覆”的结构特征和多阶段的构造演化过程。中国大陆地壳新元古代中期以来的一级构造单元有中朝、塔里木、扬子、敦煌4个陆块和中央、西北、东北、西南、东南5.造山区(带)。中朝陆块的形成源于古... 详细信息

初步探讨了中国大陆地壳“块带镶嵌多层叠覆”的结构特征和多阶段的构造演化过程。中国大陆地壳新元古代中期以来的一级构造单元有中朝、塔里木、扬子、敦煌4个陆块和中央、西北、东北、西南、东南5.造山区(带)。中朝陆块的形成源于古元古代期间发生的古大陆裂解;扬子、塔里木和敦煌陆块的形成源于新元古代早期发生的古大陆裂解。西北造山区的形成源于古生代晚期洋盆关闭、大陆碰撞并叠加新生代陆内再造山;东北造山带的形成过程包括古生代碰撞造山及中生代增生、碰撞造山;中央造山带至三叠纪大陆碰撞才最后形成并叠加有新生代再造山;东南造山带的形成经历了古生代至新生代的多次造山作用;西南造山带主要是中—新生代造山作用的产物。这些单元都具有“块带镶嵌多层叠覆”的结构特征和多阶段构造演化的特点。中国大陆地壳的形成与演化可以划分为太古宙—古元古代、中元古代—新元古代早期、新元古代中期—古新世和始新世以来4个构造阶段,每个阶段都对应不同的超大陆裂解-聚合旋回。其中新元古代中期以来的地壳形成演化与全球洋陆格局中的古亚洲洋、古特提斯洋、古太平洋、特提斯洋和太平洋5.动力学体制有关,相应地可以归结为古亚洲、古特提斯、古太平洋、特提斯和太平洋5.造山域。

关键词：中国大陆地壳块带镶嵌多层叠覆超大陆裂解-聚合旋回动力学体制造山域

Coupling effect on the thermal hazard assessment of hazardous chemical materials via calorimetric technologies and simulation approaches

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Defence Technology（防务技术） 2024年第2期32卷 644-654页

作者： Yabei xu Jiankun Shao Wei Wang Shengliang xu Dongping Chen State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China Science and Technology on Aerospace Chemical Power Laboratory Hubei Institute of Aerospace ChemotechnologyXiangyang 441003China

The coupling effect of heat absorption and release exists in the thermal decomposition of a few chemical ***,the impact of the above coupling on thermal hazard assessment is not considered in the literature *** this work,nitroguanidine(NQ)and 1,3,5.trinitro-1,3,5.triazine(RDX)are selected as representative materials to explore the influence of the coupling effect on the thermal hazard assessment of chemical *** linear heating experiments of NQ and RDX are carried out by a microcalorimeter and synchronous thermal *** thermal decomposition curves are decoupled by advanced thermokinetics *** thermal decomposition and kinetic parameters before and after decoupling are *** results of TG experiment show that both NQ and RDX began to lose mass during the endothermic *** endothermic melting and exothermic decomposition of NQ and RDX are coupled within this *** coupling effect has different degrees of influence on its initial decomposition temperature and safety *** with the parameters in the coupling state,the initial decomposition temperature and adiabatic induction period after decoupling *** self-accelerating decomposition temperature increases,and internal thermal runaway time *** the thermal hazard assessment of chemical materials with coupling effects,the calculated parameters after decoupling should be taken as an important safety index。

关键词： Calorimetric technologies Kinetics Thermal hazard Phase transformation Thermal decomposition

No apparent lock-in depth of the Laschamp geomagnetic excursion: Evidence from the Malan loess

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Science China Earth sciences 2006年第9期49卷 960-967页

作者： ZHU Rixiang1, LIU Qingsong1,2, PAN Yongxin1, DENG Chenglong1, ZHANG Rui1 & WANG Xianfeng3 1. Paleomagnetism and Geochronology Laboratory (SKL of Lithosphere Evolution), institute of geology and geophysics, Chi- nese academy of sciences,{5., China 2. institute of geophysics and Planetary geophysics, University of California, Santa Cruz, CA 95.64, USA 3. Department of geology and geophysics, University of Minnesota, Minneapolis, MN 5.45., USA 1. Paleomagnetism and Geochronology Laboratory (SKL of Lithosphere Evolution) Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China 2. institute of geophysics and Planetary geophysics University of California Santa Cruz CA 95064 USA 3. Department of geology and geophysics University of Minnesota Minneapolis MN 55455 USA

The first-order chronological framework of the long-term chinese loess/paleosol sequences was based mainly on magnetostratigraphy. However, there remain arguments on the lock-in ages of the major geomagnetic reversals. This study systematically compared the stratigraphic locations of the Laschamp excursion and Henrich events (H4 at～39 ka and H5.at～48 ka) recorded by the Luochuan loess profile in the central chinese Loess Plateau. Results show that the Lascchamp excursion is bracketed well by these two cold events, and the corresponding estimated age is between about 41.7-43.7 ka, which is close to the widely accepted age of ～40-41 ka for the ***, our new results do not suggest apparent lock-in effects in the last glacial Malan loess.

关键词： chinese loess, Laschamp excursion, Henrich event, lock-in depth.

Crust and upper mantle structure beneath western China from P wave travel time tomography

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Crust and upper mantle structure beneath western China from ...

Experimental Study of the Influence of Hydrous Minerals on the Melting Behaviour of Rocks at High Temperatures and Pressures

中国科学院地质与地球物理研究所2002学术年会

作者： Yi xu Futian Liu Jianhua Liu Hui Chen institute of geology and geophysics,chinese {5. of {5.,beijing,China

Three-dimensional velocity images of the crust and upper mantle beneath western China are obtained through seismic tomography by using first P wave arrival times of local/regional and teleseismic events recorded in chinese and Kyrgyzhstan seismic *** shallow depths,most mountain belts and tectonically elevated areas are imaged as higher velocities,relative to adjacent sediment-filled basins and foreland depressions with lower *** mid-lower crust depths,the Kyrgyz Tian Shan is underlain by lower velocity material and a distinct low velocity zone in the south-north direction is observed between the eastern and western parts of the chinese Tian *** Moho of the southern Tarim basin has a greater depth over 5. km in front of the western Kun Lun,compared to the northern and western Tarim *** heterogeneity within the upper mantle is apparent at depths from 71 km to 5.1 *** uppermost mantle beneath the Kyrgyz Tian Shan,Altay,Qi Lian and eastern Kun Lun is characterized by low velocity material that is probably related to the upwelling of hot *** lithospheric thickness varies from 120-170 km beneath the chinese Tian Shan and northern Tibetan plateau to 200-25. km beneath the Tarim *** coupling pattern of the chinese Tian Shan with adjacent provinces can be classified into the embedding,detaching and sinking,and underthrusting of lithospheric *** addition,the lithosphere of the northern edge of the Tibetan plateau seems to be thickened,in contrast to the central part of the northern plateau. North-dipping low velocities exist in the upper mantle between the Tibetan plateau and provinces to its north,which might indicate mantle flow from the Tibetan plateau towards surrounding areas, but it has been blocked by the thick Tarim lithosphere.

关键词： western China crust and upper mantle seismic tomography lithospheric structure continental collision

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Acta Geologica Sinica(English Edition) 1996年第2期70卷 157-167页

作者： Zheng Haifei Xie Hongsen xu Yousheng Song Maoshuang Zhang Yueming Wang Mingzai and xu Huigang Department of geology, Peking University, beijing institute of Geochemistry,{5., Guiyang,Guizhou

The experimental study on the melting of potassic basalt and eclogite with about 2% waterat 800-1300℃ and 1.0-3.5.GPa shows that the solidi of both rocks are significantly lower thanthose obtained from the previous experiments of the same type of rocks under dry conditions,and the former which is enriched in potassium has a lower melting point than the latter. It is con-sistent with the previous study. The melting temperature of eclogite increases with pressure,whereas potassic basalt has similar properties only at 1.5.2.5.GPa and>3.0 GPa, and at 2.5.3.0 GPa the melting temperature decreases with pressure. This can be explained as follows: (1)eclogite only has one hydrous mineral amphibole and the dehydous temperature is lower than thewet solidus of the rock. (2) Amphibole exists in potassic basalt at the pressures lower than 2.5.Pa and phlogopite exists at pressures higher than 2.5.GPa, and the special compositions of bothminerals determine that amphibole has a dehydration temperature higher than or close to that ofthe wet solidus of the rocks, while phlogopite has a dehydration temperature lower than that ofthe wet solidus. On the other hand the features of the continuous solidus in the experiment ofhydrous eclogite were produced by the fact that the dehydration temperature of its amphibolelower than or close to the melting temperature of the hydrous conditions. So the melting tempera-ture lowers at higher pressures. Therefore, the composition of the rocks in the lithosphere and thetypes of hydrous minerals and their stable P-T conditions are the important factors controllingthe solidi of rocks. It can quite well explain the partial melting of rocks and the origin of the lowvelocity zone in the deep lithosphere.

关键词： high-T/P hydrous minerals melting point of rock experimental condition

The Impacts of Permafrost Change on NPP and Implications:A Case of the Source Regions of Yangtze and Yellow Rivers

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Journal of Mountain Science 2011年第3期8卷 437-447页

作者： FANG Yiping QIN Dahe DING Yongjian YANG Jianping xu Keyan institute of Mountain Hazards & Environment Chinese Academy of Sciences Chengdu 610041 China Cold and Arid Regions Environmental and Engineering Research institute Chinese Academy of Sciences Lanzhou 730000 China Graduate School of chinese academy of sciences Beijing 100049 China

This paper studies the relationship between net primary productivity (NPP) and annual average air temperature (GT) at 0cm above ground in permafrost regions by using revised Chikugo NPP model,cubic spline interpolating functions,and non-linear regression *** source regions of the Yangtze and Yellow Rivers were selected as the research *** illustrate that:(1) There is significant non-linear relationship between NPP and GT in various typical years;(2) The maximum value of NPP is 6.17,5.87,7.73,and 5.41 DM·t·hm-2 ·a-1 respectively,and the corresponding GT is 7.1,10.0,21.2,and 8.9 o C respectively in 1980,1990,2000 and 2007;(3) In 1980,the sensitivity of NPP to GT is higher than in 1990,2000 and *** tendency shows that the NPP presents change from fluctuation to an adaptation process over time;(4) During 1980～2007,the accumulated NPP was reduced to 8.05.and the corresponding carrying capacity of theoretical livestock reduced by 11%;(5. The shape of the demonstration region of ecological compensation system,livelihood support system,and science appraisal system in the source regions of Yangtze and Yellow Rivers are an important research for increasing the adaptation capacity and balancing protection and development.

关键词： The source regions of Yangtze and Yellow Rivers Permafrost Ground temperature (GT) Net primary productivity (NPP) Policy adaptation

Drifting bands of solar radio spikes

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chinese Science Bulletin 2008年第4期53卷 638-640页

作者： xu FuYing1,2& WU HongAo1,2 1 Purple Mountain Observatory,chinese academy of sciences,Nanjing 210008,China 2 National Astronomical Observatories,chinese academy of sciences,beijing 100012,China Purple Mountain Observatory Chinese Academy of Sciences Nanjing China National Astronomical Observatories Chinese Academy of Sciences Beijing China

The solar flare(1N/C5.3) occurred in NOAA 8742 on October 27,1999,and the accompanied complex radio burst was observed by the spectrometer with both high temporal(5.ms) and frequency(10 MHz) resolutions at Purple Mountain Observatory(PMO).It started at 04:27:42 UT,peaked at 04:28:42 UT and ended at 04:29:18 *** most significant feature of the event might be the sequential spikes in both time and frequency to form three slow drift bands over the frequency range of ～5.to ≥7.5.GHz with almost the same drift rate about 2.7 GHz/*** relative bandwidth for the individual spikes varied from 1.6% to 4.9%,typically 3.3%.Based on electron cyclotron maser action driven by loss-cone anisotropy,the rare phenomena of slow drift band consisting of spikes were interpreted by spike source moving back and forth along the magnetic ***,the estimations of the narrow bandwidths of spike given by electron cyclotron maser theory coincided well with the observations.

关键词：太阳耀斑微波爆裂太阳活动天文学