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1Numerical simulation of mechanisms of deformation,failure and energy dissipation in porous rock media subjected to wave stresses显示文摘The pore characteristics,mineral compositions,physical and mechanical properties of the subarkose sandstones were acquired by means of CT scan,X-ray diffraction and physical tests.A few physical models possessing the same pore characteristics and matrix properties but different porosities compared to the natural sandstones were developed.The 3D finite element models of the rock media with varied porosities were established based on the CT image processing of the physical models and the MIMICS software platform.The failure processes of the porous rock media loaded by the split Hopkinson pressure bar(SHPB) were simulated by satisfying the elastic wave propagation theory.The dynamic responses,stress transition,deformation and failure mechanisms of the porous rock media subjected to the wave stresses were analyzed.It is shown that an explicit and quantitative analysis of the stress,strain and deformation and failure mechanisms of porous rocks under the wave stresses can be achieved by using the developed 3D finite element models.With applied wave stresses of certain amplitude and velocity,no evident pore deformation was observed for the rock media with a porosity less than 15%.The deformation is dominantly the combination of microplasticity(shear strain),cracking(tensile strain) of matrix and coalescence of the cracked regions around pores.Shear stresses lead to microplasticity,while tensile stresses result in cracking of the matrix.Cracking and coalescence of the matrix elements in the neighborhood of pores resulted from the high transverse tensile stress or tensile strain which exceeded the threshold values.The simulation results of stress wave propagation,deformation and failure mechanisms and energy dissipation in porous rock media were in good agreement with the physical tests.The present study provides a reference for analyzing the intrinsic mechanisms of the complex dynamic response,stress transit mode,deformation and failure mechanisms and the disaster mechanisms of rock media.JU Yang1,2,WANG HuiJie1,YANG YongMing1,HU QinAng3 & PENG RuiDong1 1 State Key Laboratory of Coal Resources and Safe Mining,Beijing Key Laboratory of Fracture and Damage Mechanics of Rock and Concrete,China University of Mining and Technology,Beijing 100083,China 2 Department of Mechanical and Manufacturing Engineering,University of Calgary,Calgary,Alberta,T2N 1N4,Canada 3 School of Environment and Civil Engineering,College of Engineering,Oklahoma State University,Stillwater,OK 74078,USA 2010Science China(Technological Sciences)2010,53,4:32
2Prevention and Treatment of Osteoporosis with Chinese Herbal Medicines显示文摘In this paper,laboratory reports,medication rules,formulating principles,and research methods are summarized and analyzed,including single herb,compound herbs,and the problems in the prevention and treatment of osteoporosis(OP) within the past decade.With widely recognized efficacy,satisfying achievements have been achieved in preventing and treating OP with Chinese herbal medicines(CHM).However,due to the complex constituents,the pharmacological activities and mechanism of CHM are not clear yet,and there is no unified standard on the diagnosis and syndrome differentiation of OP and the efficacy evaluation of CHM in the treatment.Accordingly,the research in the future should focus on the pharmacology and standardization of CHM in treating OP.ZHAO Xiao-ling1,2,FENG Yu-xiong1,2,3,PENG Yong1,2 1.Institute of Medicinal Plant Development,Chinese Academy of Medical Sciences and Peking Union Medical College,Beijing 100193,China 2.Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicines,Ministry of Education,Beijing 100193,China 3.College of Basic Medicine,Guangxi University of Chinese Medicine,Nanning 530001,China 2012Chinese Herbal Medicines2012,4,4:28
3Different Effects of Homocysteine and Oxidized Low Density Lipoprotein on Methylation Status in the Promoter Region of the Estrogen Receptor α Gene显示文摘我们调查了人的效果半胱氨酸(Hcy ) 和在雌激素受体高山的倡导者区域的 DNA methylation 上的氧化低密度脂蛋白(ox-LDL ) 哈(ERalpha ) 基因,和它在动脉粥样硬化的致病的潜在的机制。人的有教养的光滑的肌肉房间(SMC ) 被 Hcy 和 ox-LDL 为时间的不同经期与不同集中对待。DNA methylation 地位是由嵌套的 methylation 特定的聚合酶链反应的 assayed,在 SMC 和泡沫房间形成积累了的类脂化合物被检验,油红 O 染色。SMC 的增长是由 the3-(4,5-dimethylthiazol-2-yl ) 的 assayed -2,5-diphenyltetrazolium 溴化物方法。结果证明 ox-LDLin 节制导致的集中(10-40 mg/L ) 在 SMCs.However 的 ERagene 的倡导者区域的 de novo methylation, ox-LDL 的高集中(50 mg/L ) ,导致了时代的 demethylation。 Hcytreatment 与 aconcentration 在时代基因的倡导者区域导致了 de novo methylation --并且对待时间依赖者举止,并且在 SMCproliferation.These 数据上支持效果的一个剂量依赖者显示为动脉粥样硬化的二个风险因素有在 SMCs.However 的时代基因的倡导者区域导致 de novo methylation 的功能, ox-LDL 的高集中( 50 mg/L )导致了 demethylation ,显示有不同力量力量的动脉粥样硬化的不同风险因素在时代基因的倡导者区域引起不同异常 methylation 模式。Hcy 的 atherogenic 机制可能包含 hypermethylationof 时代基因,在动脉粥样硬化患者损害导致 SMC 的增长。Yushan HUANG~1 Kejun PENG~2 Juan SU~1 Yuping HUANG~3 Yizhon XU~1 and Shuren WANG~1 ~1Department of Pathophysiology,West China School of Preclinic Medical Sciences & Forensic Medicine,Sichuan University,Chengdu 610041.China ~2Department of Laboratory Medicine,Chengdu Medical College,Chengdu 610500,China ~3Department of Biochemistry and Molecular Bilogy,Gannan Medical College,Ganzhou 341000,China 2007Acta Biochimica et Biophysica Sinica2007,39,1:25
4Study of ozone “weekend effect” in Shanghai显示文摘Analysis of observed ozone data in 2006 from five monitoring sites (Xujiahui, Chongming, Baoshan, Pudong, Jinshan) in Shanghai reveals that ozone (O_3) concentrations in Xujiahui are higher at week-ends than those on weekdays, despite the fact that emissions of ozone precursor substances, such as oxides of nitrogen (NOx), carbon monoxide (CO) and volatile organic compounds (VOCs) are lower at weekends than those on weekdays. The possible chemical cause of ozone 'weekend effect' is that NO_2/NO ratio increases at weekends by 25.61% compared with those on weekdays. In addition, because of an average 12.13% reduction in NOx (NO + NO_2) in the early morning (05:00-09:00) at weekends compared with that on weekdays, the ozone inhibition period ends 0.5 h earlier at weekends resulting in the longer duration of ozone accumulation and the higher ozone production rate. The rate of ozone production is a function of VOCs and NOx in the atmosphere. VOCs/NOx ratio in Xujiahui is 4.55 at weekends, and 4.37 on weekdays, belonging to the 'NOx-limited'. The increasing VOCs/NOx ratio at weekends leads to ozone enhancement from 73 ppbv to 80 ppbv, which are consistent with ozone 'weekend effect' in Xujiahui. Furthermore, combining with MICAPS cloud amount data, the fact that ozone 'weekend effect' in Xujiahui weakens gradually along with the increasing of cloud amount indicates that ozone photochemical production leads to ozone 'weekend effect' in Xujiahui of Shanghai.TANG WenYuan1↑, ZHAO ChunSheng1, GENG FuHai1,2, PENG Li2, ZHOU GuangQiang2, GAO Wei2, XU JianMing2 & TIE XueXi2,3 1 Department of Atmospheric Science, School of Physics, Peking University, Beijing 100871, China 2 Atmospheric Chemistry Laboratory of Shanghai Meteorological Bureau, Shanghai 200030, China 3 Atmospheric Chemistry Division, NCAR, Boulder CO 80301, USA 2008Science China Earth Sciences2008,51,9:23
5Influence of stacking fault energy on formation of long period stacking ordered structures in Mg-Zn-Y-Zr alloysFu-sheng PAN~(1,2),Su-qin LUO~1,Ai-tao TANG~(1,2),Jian PENG~(1,2),Yun LU~3 1.College of Materials Science and Engineering,Chongqing University,Chongqing 400044,China 2.National Engineering Research Center for Magnesium Alloys,Chongqing University,Chongqing 400044,China 3.Faculty of Engineering,Chiba University,Chiba 263-8522,Japan 2011Progress in Natural Science:Materials International2011,21,6:17
6Carbon isotope ratios of C_(4) plants in loess areas of North China显示文摘Carbon isotope ratios (δ 13C) of 89 C4 plant samples were determined from the loess area in North China. δ 13C values vary between –10.5‰ and –14.6‰ with a mean of –12.6‰. Along a pre-cipitation gradient from the semi-moist area to the semiarid area, then to the arid area, the δ 13C val-ues of C4 plants show a slight decreasing trend. The δ 13C values of C4 plants in the dry season are found lower than those in the wet season. These trends are opposite to those observed for C3 spe-cies.WANG Guoan1,2,3, HAN Jiamao 2, ZHOU Liping3, XIONG Xiaogang4, TAN Ming2, WU Zhenhai5 & PENG Jun6 1. Department of Plant Nutrition, China Agricultural University, Beijing 100094, China 2. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China 3. College of Environmental Sciences, MOE Laboratory for Earth Surface Processes, Peking University, Beijing 100871, China 4. Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China 5. Northwest Sci-Tech University of Agriculture and Forestry, Yangling 712100, China 6. Network Center, China Agricultural University, Beijing 100094, China 2006Science China Earth Sciences2006,49,1:16
7An accurately delineated Permian-Triassic Boundary in continental successions显示文摘The Permian-Triassic Boundary Stratigraphic Set (PTBST), characteristic of the GSSP section of Meishan and widespread in marine Permian-Triassic Boundary (PTB) sequences of South China, is used to trace and recognize the PTB in a continental sequence at Chahe (Beds 66f―68c). Diversified Permian plant fossils extended to the PTBST, and a few relicts survived above that level. Sporomorphs are dominated by fern spores of Permian nature below the PTBST, above which they are replaced by gymnosperm pollen of Triassic aspect. In the nearby Zhejue Section, the continental PTBST is charac- terized by the fungal 'spike' recorded in many places throughout the world. The boundary claybeds (66f and 68a,c) of the PTBST are composed of mixed illite-montmorillonite layers analogous with those at Meishan. They contain volcanogenic minerals such as β quartz and zircon. U/Pb dating of the upper claybed gives ages of 247.5 and 252.6 Ma for Beds 68a and 68c respectively, averaging 250 Ma. In con- trast to the situation in Xinjiang and South Africa, the sediment sequence of the Permian-Triassic tran- sition in the Chahe section (Beds 56―80) become finer upward. Shallowing and coarsening upward is not, therefore, characteristic of the Permian-Triassic transition everywhere. The occurrence of relicts of the Gigantopteris Flora in the Kayitou Fm. indicates that, unlike most marine biota, relicts of this pa- leophytic flora survived into the earliest Triassic. It is concluded that Bed 67 at Chahe corresponds to Bed 27 at Meishan, and that the PTB should be put within the 60-cm-thick Bed 67b④, now put at its base tentatively. This is the most accurate correlation of the PTB in continental facies with that in the marine GSSP.YIN HongFu1, YANG FengQing2, YU JianXin2, PENG YuanQiao1, WANG ShangYan3 & ZHANG SuXin1 1 Laboratory of Biological and Environmental Geology, China University of Geosciences, Wuhan 430074, China 2 State Key Laboratory of Geological Process and Mineral Resources, China University of Geosciences, Wuhan 430074, China 3 Geological Survey of Guizhou Province, Guiyang 550011, China 2007Science China Earth Sciences2007,50,9:13
8Comparative analysis of astaxanthin and its esters in the mutant E1 of Haematococcus pluvialis and other green algae by HPLC with a C30 column显示文摘A gradient reversed-phase high-performance liquid chromatography (HPLC) method using a C30 col-umn was developed for the simultaneous determination of astaxanthin, astaxanthin monoesters and astaxanthin diesters in the green algae Chlorococcum sp., Chlorella zofingiensis, Haematococcus plu-vialis and the mutant E1, which was obtained from the mutagenesis of H. pluvialis by exposure to UV-irradiation and ethyl methanesulphonate (EMS) with subsequent screening using nicotine. The re-sults showed that the contents of total astaxanthins including free astaxanthin and astaxanthin esters ranged from 1.4 to 30.9 mg/g dry biomass in these green algae. The lower total astaxanthin levels (< 2 mg/g dry biomass) were detected in the green algae Chlorococcum sp. and C. zofingiensis. The higher total astaxanthin levels (>16 mg/g dry biomass) were found in the green alga H. pluvialis and its mutant E1. It is notable that the mutant E1 is found to have considerably higher amounts of total astaxanthin (30.9 mg/g) as compared to the wild strain of H. pluvialis (16.1 mg/g). This indicates that UV-irradiation and EMS compound mutagenesis with subsequent screening using nicotine is an effective method for breeding of a high-producing astaxanthin strain of H. pluvialis. In addition, the green alga C. zofingien-sis had a remarkably higher percentage of astaxanthin diesters (76.3% of total astaxanthins) and a re-markably lower percentage of astaxanthin monoesters (18.0% of total astaxanthins) in comparison with H. pluvialis (35.5% for diesters and 60.9% for monoesters), the mutant E1 (49.1% and 48.1%) and Chlorococcum sp. (18.0% and 58.6%).PENG Juan1, XIANG WenZhou2,1, TANG QuanMing1, SUN Ni1, CHEN Feng1,3 & YUAN JianPing 4 1 South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China 2 Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China 3 School of Biological Sciences, The University of Hong Kong, Hong Kong, China 4 Institute of Oceanology & College of Life Sciences, Sun Yat-Sen University, Guangzhou 510301, China 2008Science China(Life Sciences)2008,51,12:12
9Thermal-mechanical coupled effect on fracture mechanism and plastic characteristics of sandstone显示文摘Scanning electronic microscopy (SEM) was employed to investigate fractographs of sandstone in mine roof strata under thermal-mechanical coupled effect. Based on the evolution of sandstone surface morphology in the failure process and frac- tography, the fracture mechanism was studied and classified under meso and mi- cro scales, respectively. The differences between fractographs under different tem- peratures were examined in detail. Under high temperature, fatigue fracture and plastic deformation occurred in the fracture surface. Therefore, the temperature was manifested by these phenomena to influence strongly on micro failure mechanism of sandstone. In addition, the failure mechanism would transit from brittle failure mechanism at low temperature to coupled brittle-ductile failure mechanism at high temperature. The variation of sandstone strength under differ- ent temperature can be attributed to the occurrence of plastic deformation, fatigue fracture, and microcracking. The fatigue striations in the fracture surfaces under high temperature may be interpreted as micro fold. And the coupled effect of tem- perature and tensile stress may be another formation mechanism of micro fold in geology.ZUO JianPing1,2, XIE HePing2,3, ZHOU HongWei1,2 PENG SuPing1 1 State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Beijing 100083, China 2 Institute of Rock Mechanics and Fractals, China University of Mining and Technology, Beijing 100083, China 3 Sichuan University, Chengdu 610065, China 2007Science China(Technological Sciences)2007,50,6:11
10Multi-spectral image fusion method based on two channels non-separable wavelets显示文摘A construction method of two channels non-separable wavelets filter bank which dilation matrix is [1, 1; 1, ?1] and its application in the fusion of multi-spectral image are presented. Many 4×4 filter banks are designed. The multi-spectral image fusion algorithm based on this kind of wavelet is proposed. Using this filter bank, multi-resolution wavelet decomposition of the intensity of multi-spectral image and panchromatic image is performed, and the two low-frequency components of the intensity and the panchromatic image are merged by using a tradeoff parameter. The experiment results show that this method is good in the preservation of spec-tral quality and high spatial resolution information. Its performance in preserving spectral quality and high spatial information is better than the fusion method based on DWFT and IHS. When the parameter t is closed to 1, the fused image can obtain rich spectral information from the original MS image. The amount of computation reduced to only half of the fusion method based on four channels wavelet trans-form.LIU Bin1,2 & PENG JiaXiong3 1 School of Mathematics and Computer Science, Hubei University, Wuhan 430062, China 2 Key Laboratory of Applied Mathematics of Hubei Province, Wuhan 430062, China 3 Institute of Image Recognition and Artificial Intelligence, Huazhong University of Science and Technology, Wuhan 430074, China 2008Science in China(Series F)2008,51,12:9
11Changes in biodiversity and ecosystem function during the restoration of a tropical forest in south china显示文摘Tropical forests continue to vanish rapidly,but few long-term studies have ever examined if and how the lost forests can be restored.Based on a 45-year restoration study in south China,we found that a tropical rain forest,once completely destroyed,could not recover naturally without deliberate restoration efforts.We identified two kinds of thresholds that must be overcome with human ameliorative measures before the ecosystem was able to recover.The first threshold was imposed primarily by extreme physical conditions such as exceedingly high surface temperature and impoverished soil,while the second was characterized by a critical level of biodiversity and a landscape context that accommodates dispersal and colonization processes.Our three treatment catchments(un-restored barren land,single-species plantation,and mixed-forest stand)exhibited dramatically different changes in biodiversity and ecosystem functioning over 4 decades.The mixed forest,having the highest level of biodiversity and ecosystem functioning,possesses several major properties of tropical rain forest.These findings may have important implications for the restoration of many severely degraded or lost tropical forest ecosystems.REN Hai,LI ZhiAn,SHEN WeiJun,YU ZuoYue,PENG ShaoLin,LIAO ChongHui,DING MingMao & WU JianGuo 1 South China Botanical Garden,Chinese Academy of Sciences,Guangzhou 510650,China 2 Institute of Ecology and Evolution,Zhongshan University,Guangzhou 510275,China 3 Guangdong Institute of Entomology,Guangzhou 510275,China 4 School of Life Sciences and Global Institute of Sustainability,Arizona State University,Tempe,AZ 85287,USA 2007Science China(Life Sciences)2007,50,2:9
12The results and prognosis of different treatment modalities for solitary metastatic lung tumor from nasopharyngeal carcinoma:a retrospective study of 105 cases显示文摘Background and Objective:Nasopharyngeal carcinoma (NPC) is known for its propensity for distant metastases.Lung metastasis is one of the most important causes of death for patients with NPC.Solitary metastatic lung tumor from NPC is a distinctive group associated with a better survival.This study was to find a more effective treatment modality and prognostic factors for the group.Methods:Clinical data of 105 cases of solitary metastatic lung tumor from NPC were retrospectively analyzed.Survival rate was calculated by the Kaplan-Meier method.The difference of survival between the patients treated by different modalities was evaluated by the log-rank test.The Cox univariate and multivariate analyses of gender, age, pathologic type, stage, adjuvant chemotherapy, evaluation of treatment for NPC, disease-free interval, size of metastatic tumor, pulmonary hilar and/or mediastinal lymph node metastasis, treatment modalities, recurrent distant metastases and/or relapse of NPC were conducted.Results:The local control rate was 53.8% in chemotherapy group, 88.0% in radiotherapy +/-chemotherapy group, and 96.4% in operation +/-chemotherapy group (P<0.01).The most promising progression-free survival (PFS) and overall survival (OS) were obtained with operation +/-chemotherapy and followed by radiotherapy +/-chemotherapy.Both of them showed much better efficacy than chemotherapy (P<0.001).The Cox multivariate analysis showed that recurrent distant metastases and/or relapse of NPC affected the survival (OR=2.087, 95% CI=1.277-3.410, P=0.003).The T stage of NPC, size of metastatic tumor, hilar and/or mediastinal lymph node metastasis, and the treatment modality were independent prognostic factors.Conclusions:Operation +/-chemotherapy and radiotherapy +/-chemotherapy are better treatment of solitary metastatic lung tumor from NPC, which could improve the local control and prolong the PFS and OS.Chemotherapy is recommended for patients with higher T stage of NPC, size of metastatic tumor ≥3 cm, pulmonary hilar and/or mediastinal lymph node metastasis.Jun Ma1,2, Zhe-Sheng Wen1,2, Peng Lin1,2, Xin Wang1,2, Fang-Yun Xie1,3 1 State Key Laboratory of Oncology in South China, Guangzhou, Guangdong 510060, P.R.China 2 Department of Thoracic Oncology, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong 510060, P.R.China 3 Department of Radiation Oncology, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong 510060, P.R.China Department of Thoracic Surgery, Shanxi Provincial People’s Hospital, Taiyuan, Shanxi 030012, P.R.China 2010Chinese Journal of Cancer2010,29,9:9
13Characteristic atom arranging crystallogphy of alloy phases for Au-Cu system显示文摘In this paper,it is pointed out that the descriptions of alloy phase structures are dependent on structural unit sequence.In the systematic science of alloys(SSA),the alloy phase structures are described by means of the symmetry element sequence combining with characteristic atom sequence.It is named the characteristic atom arranging structure,which can display the characteristic atoms at the lattice sites and the micro-inhomogeneity,besides the symmetry.Each characteristic atom has its own characters:neighboring configuration,potential energy,volume and electronic structure.The micro-inhomogeneity of alloy phases can be described by concentrations and short-range ordered parameters of characteristic atoms.The differences between the electronic structures of alloy phases and electronic structures of characteristic atoms in the alloy phases are also discussed.XIE YouQing1,2,3,LIU XinBi1,2,3,PENG HongJian4,NIE YaoZhuang5,LI XiaoBo6 & LI YanFen1,2,3 1 School of Materials Science and Engineering,Central South University,Changsha 410083,China 2 Powder Metallurgy Research Institute,Central South University,Changsha 410083 China 3 State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China 4 School of Chemistry and Chemical Engineering,Central South University,Changsha 410083,China 5 School of Physical Science and Technique,Central South University,Changsha,410083,China 6 College of Mechanical Engineering,Xiangtan University,Xiangtan 411105,China 2011Science China(Technological Sciences)2011,54,6:8
14The ploidy effects in plant gene expression: Progress, problems and prospects显示文摘Polyploidy and haploid are widely employed in the studies of genetics and evolution, and great pro-gress has been made in these fields, inspiring the enthusiasm of scientists to explore the ploidy effects in gene expression. In this paper, we review the gene expression and its regulation in polyploids, es-pecially in autopolyploids. We summarize some limitations in previous reports on polyploidy gene ex-pression and its regulation, especially the limitations in the research materials. We propose an idea to create homologous ploidy series with twin-seedlings and to employ high-throughput techniques to investigate the polyploidy transcriptome and its regulation.PENG Hai1, ZHANG Jing1 & WU XianJun2,3 1 Laboratory of Germplasm and Genetics, College of Life Science, Jianghan University, Wuhan 430056, China 2 Rice Research Institute of Sichuan Agricultural University, Chengdu 611130, China 3 Key Laboratory of Southwest Crop Genetic Resources and Improvement of the Ministry of Education, Sichuan Agricultural Univer-sity, Ya‘an 620514, China 2008Science China(Life Sciences)2008,51,4:8
15Ambient noise near the sea-route显示文摘Ambient noise data measured in an experiment conducted in shallow water near a sea-route were analyzed. It was observed that, at low frequency, the horizontal correlation has an obvious difference from that predicted by the classical ambient noise model. The theoretical analyses show that this phenomenon is caused by wind noise together with the discrete shipping noise nearby. An ambient noise model was proposed to include the effects caused by both the noise sources. Data measured at different times verify that the proposed model can be used to forecast the ambient noise field in shallow water near the sea-route.HE Li1,2, LI ZhengLin1,3 & PENG ZhaoHui1 1 National Laboratory of Acoustics, Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190, China 2 Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China 3 NanHai Laboratory of Acoustics, Institute of Acoustics, Chinese Academy of Sciences, Haikou 570206, China 2009Science China(Physics,Mechanics & Astronomy)2009,52,1:5
16Response of remotely sensed Normalized Difference Water Deviation Index to the 2006 Drought of eastern Sichuan Basin显示文摘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.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 2008Science China Earth Sciences2008,51,5:5
17Remote sensing and geographic information systems in the spatial temporal dynamics modeling of infectious diseases显示文摘Similar to species immigration or exotic species invasion,infectious disease transmis-sion is strengthened due to the globalization of human activities. Using schistosomiasis as an exam-ple,we propose a conceptual model simulating the spatio-temporal dynamics of infectious diseases. We base the model on the knowledge of the interrelationship among the source,media,and the hosts of the disease. With the endemics data of schistosomiasis in Xichang,China,we demonstrate that the conceptual model is feasible; we introduce how remote sensing and geographic information systems techniques can be used in support of spatio-temporal modeling; we compare the different effects caused to the entire population when selecting different groups of people for schistosomiasis control. Our work illustrates the importance of such a modeling tool in supporting spatial decisions. Our mod-eling method can be directly applied to such infectious diseases as the plague,lyme disease,and hemorrhagic fever with renal syndrome. The application of remote sensing and geographic informa-tion systems can shed light on the modeling of other infectious disease and invasive species studies.GONG Peng 1,XU Bing 2 & LIANG Song 1、3 1. State Key Laboratory of Remote Sensing Science,Jointly Sponsored by the Institute of Remote Sensing Applications,Chi-nese Academy of Sciences and Beijing Normal University,Box 9718,Beijing 100101,China 2. Department of Geography,University of Utah,Salt Lake City,UT 84112,USA 3. School of Public Health,University of California,Berkeley,CA 94720,USA 2006Science China(Life Sciences)2006,49,6:5
18The microarray analysis for gene expression in haploids and diploids derived from twin-seedling rice显示文摘In this study, microarray technique was employed to analyze the gene expression at the RNA level between haploids and corresponding diploids derived from a rice twin-seedling line SARII-628. Differ- ent degrees of expression variations were observed in the plant after haploidization. The main results are as follows: (1) after haploidization, the ratio of the sensitive loci was 2.47% of the total loci designed on chip. Those loci were randomly distributed on the 12 pairs of rice chromosomes and the activated loci were more than the silenced ones. (2) Gene clusters on chromosome were observed for 33 se- quences. (3) GoPipe function classification for 575 sensitive loci revealed an involvement in the bio- logical process, cell component and molecular function. (4) RT-PCR generally validated the result from microarray with a coincidence rate of 83.78%. And for the randomly-selected activated or silenced loci in chip analysis, the coincidence rate was up to 91.86%.ZHANG HongYu1,3, PENG Hai2*, LI PingChuan1, DENG QiMing1, XU PeiZhou1, LI Yun4, WANG XuDong1 & WU XianJun1,3 1 Rice Research Institute of Sichuan Agricultural University, Chengdu 611130, China 2 Laboratory of Germplasm and Genetics, College of Life Science, Jianghan University, Wuhan 430056, China 3 Key Laboratory of Southwest Crop Genetic Resources and Improvement, Ministry of Education, Sichuan Agricultural University, Ya′an 620514, China 4 Crop Research Institute of Agricultural and Forestal Science Academy of Chengdu, Chengdu 611130, China 2008Science China(Life Sciences)2008,51,6:4
19Synthesis of vertically aligned carbon nanotube arrays on silicon substrates显示文摘The growth of well-aligned carbon nanotube (CNT) arrays using a heat chemical vapor deposition system on silicon substrates is reported. The growth properties of CNT arrays are studied as a function of synthesis conditions. It is found that 750℃ and 10 nm Fe film are suitable conditions for the growth of well-aligned CNT arrays. CNT arrays with a uniform diameter, thick tube wall and firm cohesion to the Si substrate can be grown for C2H2 concentration of 27%. Based on the experiment, the processes of improving the alignment of CNT arrays and cohesion between CNT arrays and Si substrates are discussed.ZHENG Ruiting1, CHENG Guoan1, PENG Yibin1, 2, ZHAO Yong1, 3, LIU Huaping1 & LIANG Changlin1 1. Key Laboratory of Radiation Beam Technology and Materials Modification of Ministry of Education, Department of Materials Science and Engineering, Beijing Normal University, Beijing 100875, China 2. School of Science, Civil Aviation University of China, Tianjin 300300, China 3. Department of Physics, Nanchang University, Nanchang 330047, China Correspondence should be addressed to Zheng Ruiting 2004Science China(Technological Sciences)2004,47,5:4
20Application of asymptotic waveform approximation technique to hybrid FE/BI method for 3D scattering显示文摘The asymptotic waveform evaluation (AWE) technique is a rational function ap- proximation method in computational mathematics, which is used in many appli- cations in computational electromagnetics. In this paper, the performance of the AWE technique in conjunction with hybrid finite element/boundary integral (FE/BI) method is firstly investigated. The formulation of the AWE applied in hybrid FE/BI method is given in detail. The characteristic implementation of the application of the AWE to the hybrid FE/BI method is discussed. Numerical results demonstrate that the AWE technique can greatly speed up the hybrid FE/BI method to acquire wide-band and wide-angle backscatter radar-cross-section (RCS) by complex tar- gets.PENG Zhen1,2,3 & SHENG XinQing2 1 Institute of Electronics, Chinese Academy of Sciences, Beijing 100080, China 2 Department of Electronic Engineering, Beijing Institute of Technology, Beijing 100081, China 3 Graduated University of Chinese Academy of Sciences, Beijing 100039, China 2007Science in China(Series F)2007,50,1:4
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