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Response of remotely sensed Normalized Difference Water Deviation Index to the 2006 Drought of eastern Sichuan Basin

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science china Earth sciences 2008年第5期51卷 748-758页

作者： ZHANG WenJiang1, LU QiFeng2, GAO ZhiQiang3 & PENG Jian4 1 School of Water Resource and Hydropower, Sichuan university, Chengdu 610065, china 2 National Satellite Meteorological center, china Meteorological Administration, beijing 100081, china 3 Institute of Geographic sciences and Natural Resources Research, Chinese Academy of sciences, beijing 100101, china 4 School of Environmental sciences, peking university, beijing 100871, china School of Water Resource and Hydropower Sichuan University Chengdu China National Statellite Meteorological center China Meteorological Administration Beijing China Institute of Geographic sciences and Natural Resources Research Chinese Academy of Sciences Beijing China School of Environmental sciences Peking University Beijing China

One of the most serious droughts in last century occurred in eastern Sichuan Basin in the summer of 2006 (hereinafter called the Drought). The response of Moderate Resolution Imaging Spectroradiometer (MODIS, boarding on NASA satellites of Terra and Aqua) to the Drought was analyzed in order to reach one practicable monitoring solution for regional soil moisture. Temporal process and spatial extension of the Drought were firstly estimated with ground meteorological and hydrological observations. Then, for the whole region of Sichuan and Chongqing, the remotely sensed Normalized Difference Water In- dex (NDWI) for the summers of 2001―2006 were calculated based on 8-day composite MODIS products, which were further used to construct a new water index (Normalized Difference Water Deviation Index, NDWDI) to examine the sensitivity of remote sensing in the Drought. The study showed that the NDWDI is more sensitive to regional drought than other absolute-soil-moisture-based indices. With the new index, the study extracted the spatial-temporal characteristics of the 2006 Drought, and explored its developing and withdrawing processes, which agreed with related statistics. Compared with ground method of drought observation, the NDWDI-based remote sensing solution of this paper is more pref- erable and practicable in that the local soil properties of water consumption and supply are implicitly taken into account, and the spatial representativity limit of ground observation is circumvented to a degree as satellite remotely senses the earth surface in a way of two-dimensional pixel matrix. So, the NDWDI-based method can be used to monitor regional soil water stress situation more practically and efficiently.

关键词： Sichuan Basin drought Normalized Difference Water Deviation Index response of remote sensing regional scale

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The theoretical research of basic function method in incompressible viscous flow and its simulations in three-dimensional aneurysms

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science china(Physics,Mechanics & Astronomy) 2009年第6期52卷 909-918页

作者： SHEN Fang1 & WU WangYi2 1 State Key Laboratory for Space Weather, center for Space science and Applied Research, Chinese Academy of sciences, beijing 100190, china 2 State Key Laboratory of Turbulence and Complex Systems & Department of Mechanics and Engineering science, peking university, beijing 100871, china State Key Laboratory for Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences Beijing China State Key Laboratory of Turbulence and Complex Systems & Department of Mechanics and Engineering science Peking University Beijing China

Basic function method is developed to treat the incompressible viscous flow. Artificial compressibility coefficient, the technique of flux splitting method and the combination of central and upwind schemes are applied to construct the basic function scheme of trigonometric function type for solving three-dimensional incompressible Navier-Stokes equations numerically. To prove the method, flows in finite-length-pipe are calculated, the velocity and pressure distribution of which solved by our method quite coincide with the exact solutions of Poiseuille flow except in the areas of entrance and exit. After the method is proved elementary, the hemodynamics in two-and three-dimensional aneurysms is researched numerically by using the basic function method of trigonometric function type and unstructured grids generation technique. The distributions of velocity, pressure and shear force in steady flow of aneurysms are calculated, and the influence of the shape of the aneurysms on the hemodynamics is studied.

关键词： basic function unstructured grid aneurysm viscous incompressible flow artificial compressibility flux splitting

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Latest cosmological constraints on Cardassian expansion models including the updated gamma-ray bursts

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Research in Astronomy and Astrophysics 2011年第9期11卷 1019-1030页

作者： Nan Liang Pu-Xun Wu Zong-Hong Zhu Department of Astronomy Beijing Normal University Beijing 100875 China center for High Energy Physics Peking University Beijing 100871 China center of Nonlinear science and Department of Physics Ningbo University Ningbo 315211 China

We constrain the Cardassian expansion models from the latest observa- tions, including the updated Gamma-ray bursts （GRBs）, which are calibrated using a cosmology independent method from the Union2 compilation of type Ia supernovae （SNe Ia）. By combining the GRB data with the joint observations from the Union2 SNe Ia set, along with the results from the Cosmic Microwave Background radia- tion observation from the seven-year Wilkinson Microwave Anisotropy Probe and the baryonic acoustic oscillation observation galaxy sample from the spectroscopic Sloan Digital Sky Survey Data Release. we find significant constraints on the model oarameters of the original Cardassian model ΩM0=0.282-0.014^0.015,n=0.03-0.05^＋0.05 and n=-0.16-3.26^＋0.25,β=0.76-0.58^＋0.34 of the modified polytropic Cardassian model, which are consistent with the ACDM model in a l-or confidence region. From the reconstruction of the deceleration parameter q（z） in Cardassian models, we obtain the transition redshift ZT = 0.73 ± 0.04 for the original Cardassian model and ZT = 0.68 ± 0.04 for the modified polytropic Cardassian model.

关键词： gamma-rays bursts -- cosmology cosmological parameters

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Principle and application of three-band gradient difference vegetation index

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science china Earth sciences 2005年第2期48卷 241-249页

作者： TANG Shihao, ZHU Qijiang, WANG Jindi, ZHOU Yuyu & ZHAO Feng Research center for Remote Sensing and GIS, Department of Geography, beijing Normal university, beijing 100875, china National Satellite Meteorological center, china Meteorological Administration, beijing 100081, china Research center for Remote Sensing and GIS Department of Geography Beijing Normal University Beijing China National Satellite Meteorological center China Meteorological Administration Beijing China

Vegetation index is a simple, effective and experiential measurement of terrestrial vegetation activity, and plays a very important role in qualitative and quantitative remote sensing. Aiming at shortages of current vegetation indices, and starting from the analysis of vegetation spectral characteristics, we put forward a new vegetation index, the three-band gradient difference vegetation index (TGDVI), and established algorithms to inverse crown cover fraction and leaf area index (LAI) from it. Theoretical analysis and model simulation show that TGDVI has high saturation point and the ability to remove the influence of background to some degree, and the explicit functional relation with crown cover fraction and LAI can be established. Moreover, study shows that TGDVI also has the ability to partly remove the influence of thin cloud. Experiment in the Shunyi District, beijing, china shows that reasonable result can be reached using the vegetation index to retrieve LAI. We also theoretically analyzed the reason why the normalized difference vegetation index (NDVI) owns the low saturation point, and show that it is determined by the definition of NDVI and the characteristic of vegetation spectra, and is unavoidable to some degree. Meanwhile, through model simulation, we also indicate that the relationship between simple ratio vegetation index (SR) and LAI closes to a piecewise linear one instead of a linear one, which is mainly caused by the influence of background and different change rates of reflectance in red and infrared bands with LAI increasing.

关键词： vegetation index, remote sensing, LAI, crown cover fraction, remote sensing inversion.

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Synthesis and magnetic properties of CdS/α-Fe_2O_3 hierarchical nanostructures

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science china(Physics,Mechanics & Astronomy) 2009年第7期52卷 997-1002页

作者： CHEN YuJin1,2,3, SHI XiaoLing1, CAO MaoSheng1 & ZHU ChunLing4 1 School of Materials science and Engineering, beijing Institute of Technology, beijing 100081, china 2 Micro-Nano Technologies Research center, Hunan university, Changsha 410082, china 3 College of science, Harbin Engineering university, Harbin 150001, china 4 College of Material science and Chemical Engineering, Harbin Engineering university, Harbin 150001, china School of Materials science and Engineering Beijing Institute of Technology Beijing China Micro-Nano Technologies Research center Hunan University Changsha China College of science Harbin Engineering University Harbin China College of Material science and Chemical Engineering Harbin Engineering University Harbin China

CdS/α-Fe2O3 hierarchical nanostructures, where the CdS nanorods grow irregularly on the side surface of α-Fe2O3 nanorods, were synthesized via a three-step process. The diameters and lengths of CdS nanorods can be tuned by changing the ethylenediamine (EDA) and Cd ion concentrations. The magnetic investigations by superconducting quantum interference device indicate that the hierarchical nanostructures have an Morin transition at lower temperature (230 K) than that of the single bulk α-Fe2O3 materials (263 K). Importantly, the hierarchical nanostructures exhibit weakly ferromagnetic characteristics at 300 K. A sharp peak assigned to the surface trap induced emission are observed in room temperature PL spectra. Combining with the optoelectronic properties of CdS, the CdS/ α-Fe2O3 hierarchical nanostructures may be used as multi-functional materials for optoelectronic and magnetic devices.

关键词： α-Fe2O3 CdS hierarchical nanostructures magnetic properties

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The Strategy of Prevention of Blindness

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眼科学报 1997年第3期13卷 156-161页

作者： Hu ChengEye Research center, Department of Ophthalmology, peking Union medical College Hospital Chinese Academy of medical sciences , beijing 100730, china Eye Research center Department of Ophthalmology Peking Union Medical College Hospital Chinese Academy of Medical Sciences Beijing 100730 China

Object :To reduce the prevalence of blindness ot 0.30% by 2 000 in our county. Methods :To realize the about goal effectively, the 4 aspects should be included. 1. Epi-demiological survey of ocular diseases. 2. Measures of prevention and treatment of blindness. 3. Establishment of a primary network for the prevention and treatment of ocular diseases. *** the organizations for prevention of ocular *** : Restoration of eye sight can elevate people's health level, relieve the blind from sufferings and restore their work capacity. Launching a mass movement to prevent and treat blindness has significance in promoting both material and spiritual civilizations in our country . Eye science 1997; 13:156 - 161.

关键词：失明预放措施流行病学调查眼病

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Spray and forward:Efficient routing based on the Markov location prediction model for DTNs

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science china(Information sciences) 2012年第2期55卷 433-440页

作者： DANG Fei1,YANG XiaoLong1,2 & LONG KePing2 1 Research center for Optical Internet and Mobile Information Networks(COIMIN),university of Electronic science and Technology of china,Chengdu 611731,china 2 School of Computer and Communications Engineering,university of science and Technology beijing,beijing 100083.china Research center for Optical Internet and Mobile Information Networks (COIMIN) University of Electronic Science and Technology of China Chengdu China School of Computer and Communications Engineering University of Science and Technology Beijing Beijing China

Typical delay tolerant networks(DTNs)often suffer from long and variable delays,frequent connectivity disruptions,and high bit error *** DTNs,the design of an efficient routing algorithm is one of the key *** existing methods improve the accessibility probability of the data transmission by transmitting many copies of the packet to the network,but they may cause a high network *** address the tradeoff between a successful delivery ratio and the network overhead,we propose a DTN routing algorithm based on the Markov location prediction model,called the spray and forward routing algorithm(SFR).Based on historical information of the nodes,the algorithm uses the second-order Markov forecasting mechanism to predict the location of the destination node,and then forwards the data by greedy routing,which reduces the copies of packets by spraying the packets in a particular *** contrast to a fixed mode where a successful-delivery ratio and routing overhead are contradictory,a hybrid strategy with multi-copy forwarding is able to reduce the copies of the packets efficiently and at the same time maintain an acceptable successful-delivery *** simulation results show that the proposed SFR is efficient enough to provide better network performance than the spray and wait routing algorithm,in scenarios with sparse node density and fast mobility of the nodes.

关键词： delay tolerant networks spray and forward Markov position prediction routing algorithm

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Enhancement of magnetism of Zn0.95Co0.05O films by p-type Cu+ doping

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Progress in Natural science:Materials International 2011年第1期21卷 31-35页

作者： Wei-chang HAO~(1,5),Jian-jun LI~2,Huai-zhe XU~3,Jia-ou WANG~4,Tian-min WANG~1 1.center of Materials Physics and Chemistry,Beihang university,beijing 100083.china 2.Department of Materials science and Engineering, Anhui university of science and Technology,Huainan 232001,china 3.Department of Physics,Beihang university,beijing 100083.china 4.beijing Synchrotron Radiation Facility,Institute of High Energy Physics, Chinese Academy of sciences,100049,china 5.Key Laboratory of Micro-nano Measurement,Manipulation and Physics, Ministry of Education,Beihang university,beijing 100191,china center of Materials Physics and Chemistry Beihang University Beijing 100083 China Key Laboratory of Micro-nano Measurement Manipulation and Physics Ministry of Education Beihang University Beijing 100191 China Department of Materials science and Engineering Anhui University of Science and Technology Huainan 232001 China Department of Physics Beihang University Beijing 100083 China beijing Synchrotron Radiation Facility Institute of High Energy Physics Chinese Academy of Sciences 100049 China

Zn0.95Co0.05O and Zn0.91Co0.05Cu0.04O thin films were fabricated on Si（111） substrate by the reactive magnetron sputtering method at different O-Ar *** characterizations by X-ray diffractometry（XRD）,X-ray photo-electronic spectrum（XPS）, and electron paramagnetic resonance（EPR） indicate that the doped Cu ions substitute the Zn2+ions in the ZnO *** doped Cu ions are in Cu+and Cu2+mixture valence *** ferromagnetism of the Zn0.91Co0.05Cu0.04O film increases gradually the increasing Cu+ions *** results indicate that the increase of ferromagnetism is not owing to the magnetic contribution of Cu+ions themselves,but owing to the enhancement of magnetic interaction between Co ions,which suggests that p-type doping of Cu+ions plays an important role in mediating the ferromagnetic coupling between Co ions.

关键词： Zn0.95Co0.05O films Zn0.91Co0.05Cu0.04O films magnetic semiconductors magnetic coupling co-doping

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Patterns of platinum-group elements in mantle peridotite, granulite xenoliths and basalt in Hannuoba

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Chinese science Bulletin 1999年第18期44卷 1676-1681页

作者： CHU Xuelei, LI Xiaolin, XU Jiuhua and LIU Jianming1. The Research center of Mineral Resources Exploration , Chinese Academy of sciences , beijing 100101, china 2. Institute of Geology , Chinese Academy of sciences , beijing 100029, china 3. Institute of High Energy Physics , Chinese Academy of sciences , beijing 100817 , china 4. beijing university of science and Engineering , beijing 100083, china Corresponding author The Research center of Mineral Resources Exploration Chinese Academy of Sciences Beijing China Institute of Geology Chinese Academy of Sciences Beijing China Institute of High Energy Physics Chinese Academy of Sciences Beijing China beijing university of science and Engineering Beijing China

Neutron activation analysis after preconcentration of nickel sulfide fire assay was used in measurement of Ru, Ph, Pd, Os, Ir, Pt (i.e. PGE elements) and Au concentrations for basalt, mantle and granulite xenoliths in Hannuoba. The chondrite- and primitive mantle-normalized PGE patterns generally exhibit flat (for Iherzolite), negative slope (for harzburgite),

关键词： mantle xenolith granulite xenolith basalt platinum-group element Hannuoba.

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Experimental study on upward bubble velocity and pierce length distributions in a water model of copper converter

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Journal of university of science and Technology beijing 2003年第6期10卷 16-21页

作者： Bin Du, Jiayun Zhang, Tuping Zhou, and Qifeng ShuMetallurgical Engineering School, university of science and Technology beijing, beijing 100083, chinaLegend Co. Ltd., beijing 100085, china Metall. Eng. Sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China Legend Co. Ltd. Beijing 100085 China

The upward bubble velocity and the pierce length distributions in a sectionalwater model of the copper converter in Guixi Smelter in Jiangxi, china, were measured using atwo-contact electro-resistivity probe. In the case of using a single tuyere, the bubble velocitydistribution along longitudinal direction was similar to that derived from Guassian function. Beyondthe center of the longitudinal range, the bubble pierce length exhibited a sudden increase. Theupward bubble velocity at a specified location could go up to meters per second. Its probability ata fixed location obeys a lognormal function; the bubble pierce length there varies bellow a fewcentimeters. In the case of using multi-tuyeres, the upward bubble velocity was roughly uniformright above the tuyeres and showed a slow decrease beyond this region. The bubble pierce lengthwithin both of these two regions was roughly uniform. Its average value in the former region,however, was found to he somewhat lower than that in the later.

关键词： upward bubble velocity bubble pierce length distribution copper converter

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