检索结果-南通市图书馆

Validating global hydrological models by ground and space gravimetry

chinese Science Bulletin 2009年第9期54卷 1534-1542页

作者： ZHOU JiangCun1,2.3, SUN HePing1,2.& XU JianQiao1,2.1 Institute of Geodesy and Geophysics, chinese academy of sciences, Wuhan 430077, china 2.Key Laboratory of dynamic geodesy, chinese academy of sciences, Wuhan 430077, china 3 graduate University of chinese academy of sciences, beijing 100049, china Institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan 430077 China Key Laboratory of dynamic geodesy Chinese Academy of Sciences Wuhan 430077 China graduate University of chinese academy of sciences Beijing 100049 China

The long-term continuous gravity observations obtained by the superconducting gravimeters (SG) at seven globally-distributed stations are comprehensively analyzed. After removing the signals related to the Earth's tides and variations in the Earth's rotation, the gravity residuals are used to describe the seasonal fluctuations in gravity field. Meanwhile, the gravity changes due to the air pressure loading are theoretically modeled from the measurements of the local air pressure, and those due to land water and nontidal ocean loading are also calculated according to the corresponding numerical models. The numerical results show that the gravity changes due to both the air pressure and land water loading are as large as 100×10-9 m s-2.in magnitude, and about 10×10-9 m s-2.for those due to the nontidal ocean loading in the coastal area. On the other hand, the monthly-averaged gravity variations over the area surrounding the stations are derived from the spherical harmonic coefficients of the GRACE-recovered gravity fields, by using Gaussian smoothing technique in which the radius is set to be 600 km. Com-pared the land water induced gravity variations, the SG observations after removal of tides, polar mo-tion effects, air pressure and nontidal ocean loading effects and the GRACE-derived gravity variations with each other, it is inferred that both the ground- and space-based gravity observations can effec-tively detect the seasonal gravity variations with a magnitude of 100×10-9 m s-2.induced by the land water loading. This implies that high precision gravimetry is an effective technique to validate the re-liabilities of the hydrological models.

关键词：重力测量水文模型模型验证和空间地面重力变化季节性波动空气压力

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

NEW WIND WAVE GROWTH RELATIONS

引用

Journal of Hydrodynamics 2004年第5期16卷 608-614页

作者： WUShu-ping HOUYi-jun YINBao-shu InstituteofOceanology ChineseAcademyofSciencesQingdao266071China

In the present paper combining the relationship between wave steepness andwave age with the significant wave energy balance equation for wind wave, a new wind wave growthrelation is presented. Comparisons with the other existing wind wave growth relations show that theresults in present paper accord better with the wind wave growth process.

关键词： relationship between wave steepness and wave age wind wave energy balanceequation new wind wave growth relation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Strict constraints on 2. primitive pairs for engineering symbol recognition:Theory and application

引用

Science china(Information sciences) 2012年第5期55卷 1032-1041页

作者： LI Ting 1,2.QIU XianJie 1,HUANG He 1 & WANG ZhaoQi 1 1 Virtual Reality Laboratory,Institute of Computing Technology chinese academy of sciences,beijing 100190,{2. 2.graduate University of chinese academy of sciences,beijing 100049,{2. 1. Virtual Reality Laboratory Institute of Computing Technology Chinese Academy of Sciences Beijing 100190 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China

Geometric constraints on the line-line pair,line-arc pair and arcarc pair are *** con-straints are able to encode the geometric relations between lines,arcs and circles.A geometric proof is presented to demonstrate that the constraints are stable under translation,rotation,uniform scaling or reflection of the primitive *** on the constraints,an algorithm for recognizing symbols in drawings is ***-perimental results show that,compared with three other methods,our method can distinguish more primitive pairs and has higher accuracy in engineering symbol recognition.

关键词： coordinated multi-point transmission multicell cooperation capacity analysis MIMO-OFDM power allocation frequency selective MIMO channel

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

DNA barcoding:species delimitation in tree peonies

引用

Science china(Life sciences) 2009年第6期52卷 568-578页

作者： ZHANG JinMei1,2.WANG JianXiu1,2.XIA Tao1,2.& ZHOU ShiLiang1 1State Key Laboratory of Systematic and Evolutionary Botany,Institute of Botany,the chinese academy of sciences,beijing 100093,{2. 2.3} school of the chinese academy of sciences,beijing 100039,{2. 1. State Key Laboratory of Systematic and Evolutionary Botany Institute of Botany the Chinese Academy of Sciences Beijing 100093 China 2. graduate school of the chinese academy of sciences Beijing 100039 China

Delimitations of species are crucial for correct and precise identification of *** "spe-cies" is more a subjective than an objective concept in taxonomic practice due to difficulties in revealing patterns of infra-or inter-specific *** phylogenetic studies at the population level solve this problem and lay a sound foundation for DNA *** this paper we exemplify the necessity of adopting a phylogenetic concept of species in DNA barcoding for tree peonies(Paeonia ***).We used 40 samples representing all known populations of rare and endangered species and several populations of widely distributed tree *** currently recognized species and major variants have been included in this *** chloroplast gene fragments,***,rps16-trnQ,trnL-F and trnS-G(a total of 5040 characters,96 variable and 69 parsimony-informative characters) and one variable and single-copy nuclear GPAT gene fragment(2.93?2.97 bp,2.9 variable and 148 parsi-mony-informative characters) were used to construct phylogenetic relationships among the *** evolutionary lineages revealed by the nuclear gene and the chloroplast genes are inconsistent with the current circumscriptions of ***,***,***,and *** based on *** inconsistencies come from(1) significant chloroplast gene divergence but little nuclear GPAT gene divergence among population systems of *** + ***,and(2. well-diverged nuclear GPAT gene but little chloroplast gene divergence between *** and *** incongruence of the phylogenies based on the chloroplast genes and the nuclear GPAT gene is probably due to the chloro-plast capture event in evolutionary history,as no reproductive barriers exist to prevent inter-specific *** also evaluated the suitability of these genes for use as DNA barcodes for tree *** variability of chloroplast genes among well-defined species or population systems of a specie

关键词： DNA barcoding evolution Paeonia phylogeny species concept

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Adaptive quasi-likelihood estimate in generalized linear models

引用

Science china Mathematics 2005年第6期48卷 829-846页

作者： CHEN Xia & CHEN Xiru school of Mathematics and Statistics, Wuhan University, Wuhan 430072. china {2. school, chinese academy of Science, beijing 100049, china 1. school of Mathematics and Statistics Wuhan University 430072 Wuhan China 2. graduate school Chinese Academy of Science 100049 Beijing China

This paper gives a thorough theoretical treatment on the adaptive quasilikelihood estimate of the parameters in the generalized linear models. The unknown covariance matrix of the response variable is estimated by the sample. It is shown that the adaptive estimator defined in this paper is asymptotically most efficient in the sense that it is asymptotic normal, and the covariance matrix of the limit distribution coincides with the one for the quasi-likelihood estimator for the case that the covariance matrix of the response variable is completely known.

关键词： generalized linear models, quasi likelihood estimate, adaptive estimate.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Cloning and roles of goldfish maternal factor β-Catenin cDNA in embryonic development

引用

chinese Science Bulletin 2004年第7期49卷 683-688页

作者： ZHANG Jingpu1,2.WANG Weixian1 & ZHU Shaoxia1 1.Institute of Genetics and Developmental Biology,chinese academy of {2.,beijing 100080,china 2.The graduate school of the chinese academy of sciences,beijing 100039,china Correspondence should be addressed to Zhang Jingpu Institute of Genetics and Developmental Biology Chinese Academy of Sciences Beijing 100080 China The graduate school of the{2. Beijing 100039 China

Interaction between nucleus and cytoplasm has been focused in the field of animal embryonic development, in which study of maternal factors is required positively. b-Catenin, an important maternal factor in early embryo-genesis, has been analyzed in its expression pattern and func-tions in this paper. We have cloned goldfish b-Catenin cDNA gene and compared it with zebrafish b-Catenin cDNA. High homology was found in cDNA and in amino acid sequences between them, 93% (2.2./2.84 bp) and 98.5% (768/780 aa) respectively. The expression pattern of b-Catenin by in situ hybridization and the roles of b-Catenin on embryonic de-velopment by co-injection of anti-sense RNA and reporter gene, EGFP have been investigated in the whole process of goldfish embryonic development. The results suggest that b-Catenin presents dynamic distribution, mainly locates at body axis, dorsal tissues, head and tail structures after being fertilized. The loss of b-Catenin activity would cause serious destruction of embryo in dorsal tissues and in anteroposte-rior axes, and leads embryos to die before larva get hatched.

关键词：胚胎发育母体因子金鱼基因克隆氨基酸序列 cDNA 细胞质细胞核

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

CBCR:CBC MAC with rotating transformations

引用

Science china(Information sciences) 2011年第11期54卷 2247-2255页

作者： ZHANG LiTing 1,2.WU WenLing 1,ZHANG Lei 1 & WANG Peng 2. State Key Laboratory of Information Security,Institute of Software,chinese academy of {2.,beijing 100190,china 2.graduate University of chinese academy of sciences,beijing 100049,china 1. State Key Laboratory of Information Security Institute of Software Chinese Academy of Sciences Beijing 100190 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China

Message authentication codes (MACs) are widely used to protect data integrity and data origin authentication in *** this paper,we propose a new block-cipher-based MAC algorithm,CBCR,with provable security for arbitrary-length *** adopts rotating operations in the end of cipherblock-chaining structure,and it appends fixed-length prefixes to all messages,which implies flexible usages in *** example,these fixed-length prefixes can be filled with some security parameters,message redundancies,*** also propose CBCR0,a special case of CBCR that sets its prefix to be an all-zero *** with CMAC,a recommended standard by the US National Institute of Standards and Technology (NIST),CBCR0 enjoys all the advantages that CMAC has,but requires less memory;so,in practical applications,CBCR0 behaves as well as CMAC does,and it is even more suitable for environments with limited memory resources,*** cards.

关键词： message authentication code cipher block chaining block cipher provable security

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

CO observations of massive star forming regions at different evolutionary phases

引用

Science china(Physics,Mechanics & Astronomy) 2006年第5期49卷 626-640页

作者： CHEN Xi1,2. XU Ye1,3, SHEN Zhiqiang1,3 & LI Jingjing1,2.1. Shanghai Astronomical Observatory, chinese academy of sciences, Shanghai 2.0030, china {2. of the chinese academy of sciences, beijing 100034, china 3. Joint Institute for Galaxy and Cosmology, Shanghai Astronomical Observatory and the University of Science and Technology of china, Shanghai 2.0030, china Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai 200030 China graduate school of the{2. Beijing 100034 China Joint Institute for Galaxy Cosmology Shanghai Astronomical Observatory the University of Science Technology of china Shanghai 200030 China

The 12.O (J=1-0), 13CO (J=1-0) and C18O (J=1-0) emissions in 9 massive star forming regions, which are believed to be at different stages of massive star formation, were mapped with the 13.7 m millimeter wave telescope at Qinghai Station of Purple Mountain Observatory. Of the observed 9 sources, 13CO cores were detected in seven of them, and C18O cores in five of them. And only two sources associated with C18O cores and H2. masers showed the extended structures and strong outflows. This is the first detection of outflow associated with IRAS 2.566+582. in the observing field of S152.S153. The physical parameters of cores and outflows for these sources, derived from Local Thermal Equilibrium (LTE) analysis, are presented. These observing results suggest that the C18O cores will only appear when the gas density is high enough and the probability to have an outflow is very high when the clumps show the C18O and H2. maser simulta- neously.

关键词： star formation cloud core outflow H2. maser

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Preparation of Pt/K_2.a_2.i_3O_(10) and its photo-catalytic activity for hydrogen evolution from methanol water solution

引用

Science china Chemistry 2006年第2期49卷 162-168页

作者： CUI Wenquan1,3, LIU Li2. FENG Liangrong1, XU Chenghua1, LI Zijian1, Lü Shaojie1 & QIU Fali1 1. Chengdu Institute of Organic Chemistry, chinese academy of sciences, Chengdu 610041, china 2. Chemistry Department, Sichuan University of Science & Engineering, Zigong 643033, china 3. graduate school of the chinese academy of sciences, beijing 100039, china Correspondence should be addressed to Qiu Fali 1. Chengdu Institute of Organic Chemistry Chinese Academy of Sciences Chengdu 610041 China 3. graduate school of the{2. Beijing 100039 China 2. Chemistry Department Sichuan University of Science & Engineering Zigong 643033 China

A layered perovskite-type oxide K2.a2.i3O10 was prepared with high-temperature solid-state reaction, and characterized with X-ray diffraction (XRD) and ultraviolet-visible diffuse re-flectance spectroscopy (UV-Vis DRS). Platinum was loaded onto K2.a2.i3O10 as a co-catalyst with different methods. The dispersion of platinum on K2.a2.i3O10 was determined with HOT method. The photocatalytic activity of Pt/K2.a2.i3O10 was studied. This catalyst showed much higher activity in hydrogen evolution reaction than Ni/K2.a2.i3O10. The effects of different amounts of loaded platinum and several preparation methods were evaluated. The best achieved hydrogen evolution rate was 2.3.88 μmol·h?1 by Pt(2.)/K2.a2.i3O10. A possible band structure and mechanism were discussed based on the results.

关键词： photocatalysis hydrogen platinum K_2.a_2.i_3O_(10) support

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Synthetic aperture radar tomography sampling criteria and three-dimensional range migration algorithm with elevation digital spotlighting

引用

Science in china(Series F) 2009年第1期52卷 100-114页

作者： TAN WeiXian1,2.3?, HONG Wen1,2. WANG YanPing1,2. LIN Yun1,2.3 & WU YiRong1,2.1 State Key Laboratory of Microwave Imaging Technology, beijing 100190, china 2.Institute of Electronics,{2., beijing 100190, china 3 graduate school,{2., beijing 100190, china State Key Laboratory of Microwave Imaging Technology Beijing 100190 China Institute of Electronics Chinese Academy of Sciences Beijing 100190 China graduate school Chinese Academy of Sciences Beijing 100190 China

Based on the general geometric model of multi-baseline Synthetic Aperture Radar Tomography （TomoSAR）, the three-dimensional （3-D） sampling criteria, the analytic expression of the 3-D Point Spread Function （PSF） and the 3-D resolution are derived in the 3-D wavenumber domain in this paper. Considering the relationship between the observation geometry and the size of illuminated scenario, a 3-D Range Migration Algorithm with Elevation Digital Spotlighting （RMA-EDS） is proposed. With this algorithm 3-D images of the area of interest can be directly and accurately reconstructed in the 3-D space avoiding the complex operations of 3-D geometric correction. Finally, theoretical analyses and simulation results are presented to demonstrate the shift-varying property of the 3-D PSF and the spatialvarying property of the 3-D resolution and to demonstrate the validity of the 3-D RMA-EDS.

关键词： synthetic aperture radar tomography (TomoSAR) three-dimensional (3-D) SAR imaging 3-D sampling criteria 3-D resolution,3-D range migration algorithm with elevation digital spotlighting (RMA-EDS)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：