检索结果-南通市图书馆

Nitrogen isotopic composition of plant-soil in the Loess Plateau and its responding to environmental change

Chinese Science Bulletin 2009年第2期54卷 272-279页

作者： LIU Weiguo1,2.& WANG Zheng1,3.1 State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of sciences, Xi’an 710075, {2. 2.Xi’an Jiaotong university, school of Human Settlement and Civil Engineering, Xi’an 710049, {2. 3.Graduate university of Chinese Academy of sciences, beijing 100049, {2. State Key Laboratory of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Xi’an China school of Human Settlement and Civil Engineering Xi’an Jiaotong University Xi’an China Graduate university of Chinese Academy of sciences Beijing China

The nitrogen isotope of soil is of emerging significance as an indicator of climatic change and biogeochemical cycle of nitrogen in nature systems. In this paper, the nitrogen content and isotopic composition of modern ecosystems from arid and semiarid Loess Plateau in northwestern china, including plant roots and surface soil, were determined to investigate trends in δ15N variation of plant roots and soil along a precipitation and temperature gradient in northwestern china under the East Asian Monsoon climate condition. The δ15N values of surface soil from the study area vary from ?1.2. to 5.8‰, but from -5.1‰ to 1.9‰ in the plant roots. Our results indicate that (1) although the isotopic compositions of both plant roots and surface soil change with a similar trend along the climate gradient, the apparent nitrogen difference between plant roots and soil existed, with -δ15N values ranging from 0.3. to 7.2. with average of 4.1‰; and (2. mean annual precipitation (MAP) is the dominant factor for isotopic composition of plant-soil nitrogen in the Loess Plateau, and the δ15N values are less correlated with MAT; we suggest that nitrogen isotopic composition of soil is a potential tracer for environmental changes.

关键词：氮同位素物理性质化学性质环境论

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

Quick image-processing method of UAV without control points data in earthquake disaster area

引用

中国有色金属学会会刊：英文版 2011年第S3期21卷 523-528页

作者： LI Chang-chun1, ZHANG Guang-sheng1, LEI Tian-jie2. 3. GONG A-du2. 3.1. school of Surveying & Land Information Engineering, Henan Polytechnic {3., Jiaozuo 454000, {2. 2. Key Laboratory of Environmental Change and Natural Disaster, Ministry of Education, beijing Normal {3., beijing 100875, {2. 3. Ministry of Civil Affairs/Ministry of Education of {2. Academy of Disaster Reduction and Emergency Management, beijing Normal {3., beijing 100875, {2. school of Surveying & Land Information Engineering Henan Polytechnic University Jiaozuo 454000 China Key Laboratory of Environmental Change and Natural Disaster Ministry of Education Beijing Normal University Beijing 100875 China Ministry of Civil Affairs/Ministry of Education of china Academy of Disaster Reduction and Emergency Management Beijing Normal University Beijing 100875 China

The methods of unmanned aerial vehicles images splicing rapidly and rectifying without control points data, only using auxiliary data recorded by unmanned aerial vehicle (UAV) system, were researched. Two algorithms were proposed, including UAV images auto- splicing rapidly after image blocking and UAV images rectifying based on pseudo center points of auxiliary data. When SIFT algorithm for UAV images splicing is applied, the accuracy is very high, but the efficiency is very low. The splicing efficiency is improved greatly based on SIFT algorithm after image blocking. The results show that rectifying accuracy is very high and has no visual dislocation when pseudo center points of auxiliary data is applied.

关键词： unmanned aerial vehicles SIFT algorithm blocking quickly splicing rectification

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

Convergence analysis of the adaptive finite element method with the red-green refinement

引用

Science china Mathematics 2010年第2期53卷 499-512页

作者： ZHAO XuYing 1, 3., HU Jun 2.? & SHI ZhongCi 1 1 State Key Laboratory of Scientific and Engineering Computing, Institute of Computational Mathematics and Scientific/Engineering Computing, Academy of Mathematics and Systems Science, Chinese Academy of sciences, beijing 100190, {2. 2.Key Laboratory of Mathematics and Applied Mathematics (Peking university), Ministry of Education and school of mathematical sciences, Peking university, beijing 100871, {2. 3.Graduate university of Chinese Academy of sciences, beijing 100190, {2. State Key Laboratory of Scientific and Engineering Computing Institute of Computational Mathematics and Scientific/Engineering Computing Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing China Graduate university of Chinese Academy of sciences Beijing China Key Laboratory of Mathematics and Applied Mathematics (Peking university) Ministry of Education and School of Mathematical Sciences Peking University Beijing China

In this paper, we analyze the convergence of the adaptive conforming P 1 element method with the red-green refinement. Since the mesh after refining is not nested into the one before, the Galerkin-orthogonality does not hold for this case. To overcome such a difficulty, we prove some quasi-orthogonality instead under some mild condition on the initial mesh (Condition A). Consequently, we show convergence of the adaptive method by establishing the reduction of some total error. To weaken the condition on the initial mesh, we propose a modified red-green refinement and prove the convergence of the associated adaptive method under a much weaker condition on the initial mesh (Condition B).

关键词： red-green refinement adaptive finite element method convergence non-nested local refinement

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

Calculating soil moisture by remote sensing and analyzing hydrologic cycle process in the Yellow River basin

引用

Science china(Technological sciences) 2004年第Z1期47卷 1-13页

作者： YANG Shengtian1 & LIU Changming1, 2.1. school of Environmental sciences, {2. Normal university, {2. 100875, china 2. Institute of Geographic Science and Natural Resources Research, {2. 100101, china school of Environmental sciences Beijing Normal University Beijing China Institute of Geographic Science and Natural Resources Research Beijing China

Based on the AVHRR pathfinder remote sensing data, soil moisture, precipitation and evaporation during the period of 1982.1998, soil moisture of all layers of soil-profile (0—1 m) in the Yellow River basin over the 17 years are calculated by the remote sensing model of calculating soil water. The Yellow River basin is divided into seven subcatchments as control sections at the location of six hydrologic stations (Lanzhou, Toudaoguai, Longmen, Sanmenxia, Huayuankou and Lijin). After calculating soil moisture and obtaining runoff data and precipitation data, the dynamical features of hydrological cycle in the Yellow River basin are analyzed for the period from 1982.to 1988 using water balance method. The conclusions are as follows: It is feasible to calculate the soil water on the macro-scale, in the soil profile with temporal continuity by means of remote sensing and survey in land. Some values of the key water cycle factors in the Yellow River are obtained, which include the annual precipitation of 4000 km3. the evapotranspiration of 3.00-3.00 km3. and the soil moisture transformation of ?500- 500 km3. Consequently, we analyzed the process of the water cycle in the Yellow River over the 17 years, and the results show that the segment upstream of Lanzhou city is a relatively humid region, and the area of internal waters and the reaches of Shanshan is the most desiccated region. Therefore, the runoff in the depth process is intensive and the runoff-generating process is weak in more arid regions.

关键词： the Yellow River, soil moisture, remote sensing, hydrologic cycle.

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

Conceptual design,data model and key techniques of“3. Assistant”

引用

中国有色金属学会会刊：英文版 2011年第S3期21卷 692-698页

作者： LI Qing-yuan1, ZHANG Xuan2. JIN Yang2. ZHOU Hui3. WANG Qian-jin3.WEI Zhan-yin1 1. Key Laboratory of Geo-Informatics, Chinese Academy of Surveying and Mapping, {3. 10083., {2. 2. school of Geo-Science and Surveying Engineering, {2. university of Mining and Technology, {3. 100083. {2. 3. school of Geomatics, Liaoning Technical university, Fuxin 12.000, {2. Key Laboratory of Geo-Informatics Chinese Academy of Surveying and Mapping Beijing 100830 China school of Geo-Science and Surveying Engineering China University of Mining and Technology Beijing 100083 China school of Geomatics Liaoning Technical University Fuxin 123000 China

Conceptual design, data model and key techniques of "Geo-engineer 3. assistant", an underground 3. GIS oriented to geology and mine application, were discussed. In particular, the importance of high-order smoothing triangular pieces to surface's fine expression in geological modeling was emphasized. The contour mode is the most favorite mode of the three modes about surface expression: DEM, TIN and contour. Topology in underground 3. modeling with CAGD was compared. From the view of boundary and coboundary, which is soul of IS 19107 (Geographic information spatial schema), 3. underground topology was re-examined.

关键词： 3. assistant true 3. GIS fine expression of surface contour mode 3. topology

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

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 2.003., china 2. Graduate {2. of the Chinese Academy of sciences, beijing 10003., china 3. Joint Institute for Galaxy and Cosmology, Shanghai Astronomical Observatory and the university of Science and Technology of china, Shanghai 2.003., china Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai China Graduate school of the Chinese Academy of sciences Beijing China Joint Institute for Galaxy and Cosmology Shanghai Astronomical Observatory and the University of Science and Technology of China Shanghai China

The 12.O (J=1-0), 13.O (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, 13.O 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

Average Secrecy Capacity of the Reconfigurable Intelligent Surface-Assisted Integrated Satellite Unmanned Aerial Vehicle Relay Networks

引用

Computer Modeling in Engineering & sciences 2024年第2期138卷 1849-1864页

作者： ping Li Kefeng guo Feng Zhou XuelingWang Yuzhen Huang school of Information Technology Yancheng Institute of TechnologyYancheng224051China school of Space Information Space Engineering UniversityBeijing101407China Space E-Star Communication Technology Co. LtdNanjing210007China Academy of Military sciences of PLA Beijing100097China

Integrated satellite unmanned aerial vehicle relay networks(ISUAVRNs)have become a prominent topic in recent *** paper investigates the average secrecy capacity(ASC)for reconfigurable intelligent surface(RIS)-enabled ***,an eve is considered to intercept the legitimate information from the considered secrecy ***,we get detailed expressions for the ASC of the regarded secrecy system with the aid of the reconfigurable ***,to gain insightful results of the major parameters on the ASC in high signalto-noise ratio regime,the approximate investigations are further gotten,which give an efficient method to value the secrecy *** last,some representative computer results are obtained to prove the theoretical findings.

关键词： Integrated satellite unmanned aerial vehicle relay networks reconfigurable intelligent surface average secrecy capacity(ASC) asymptotic ASC

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

The Koppelman-Leray formula on complex Finsler manifolds

引用

Science china Mathematics 2005年第6期48卷 847-863页

作者： QIU Chunhui & ZHONG Tongde school of mathematical {2., Xiamen {3., Xiamen 3.1005, china Academy of Mathematics and System {2., Chinese Academy of {2., beijing 100080, china school of mathematical {2. Xiamen University Xiamen China Academy of Mathematics and System sciences Chinese Academy of Sciences Beijing China

By means of the invariant integral kernel (the Berndtsson kernel), the complex Finsler metric and the non-linear connection associated with the Chern-Finsler connection to research into the integral representation theory on complex Finsler manifolds, theKoppelman and Koppelman-Leray formulas are obtained, and the - -equations are solved.

关键词： complex Finsler manifold, Chern-Finsler connection, invariant integral kernel, Koppelman-Lerayformulas, - -equation.

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

Tumor immunological phenotype-derived gene classification predicts prognosis,treatment response,and drug candidates in ovarian cancer

引用

Genes & Diseases 2024年第5期11卷 94-97页

作者： Chengbin guo Yuqin tang Zhihai Liu a Chuanliang Chen Xun Hu Yongqiang Zhang Guangzhou Women and Children’s Medical Center Guangzhou Medical UniversityGuangzhouGuangdong 510623China Clinical Bioinformatics Experimental Center Henan Provincial People’s HospitalPeople’s Hospital of Zhengzhou UniversityZhengzhouHenan 450003China school of Pharmacy Macao University of Science and TechnologyTaipaMacao 999078China Clinical Research Center The Second Affiliated HospitalSchool of MedicineZhejiang UniversityHangzhouZhejiang 310003China Biorepository State Key Laboratory of BiotherapyWest China HospitalSichuan UniversityChengduSichuan 610041China West china school of Medicine West China HospitalSichuan UniversityChengduSichuan 610041China

The high recurrence and low responsiveness to immunotherapy make ovarian cancer(OC)the most lethal gynecological *** microenvironment is critical in risk stratification and the discovery of molecular *** developed a prognostic classification for OC,which could also predict the prognosis of other gynecological cancers including breast cancer,endometrial cancer,and cervical *** mutation,hallmark pathways,and immune landscapes were *** analysis of immune checkpoints and multiple immune signatures revealed the low-risk group responds better to immune checkpoint inhibitors,which was validated by an external immunotherapeutic cohort(IMvigor2.0).Singlecell RNA sequencing(scRNA-seq)confirmed the high expression of SERPINB1 and SERPINB9 in dendritic cells,and AlphaFold2.was used to infer their 3. protein *** molecular compounds binding to SERPINB1/SERPINB9 were predicted by virtual screening.

关键词： prognosis cancer treatment

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Plus cupping degrees do not form an ideal

引用

Science in china(Series F) 2004年第5期47卷 635-654页

作者： LI Angsheng1,2.& ZHAO Yicheng1 1. Institute of Software,Chinese Academy of sciences,beijing 100080,{2. 2. school of Information sciences,beijing Normal university,beijing 100871,{2. Institute of Software Chinese Academy of Sciences Beijing China school of Information sciences Beijing Normal University Beijing China

A computably enumerable (c.e.,for short)degree a is called plus cupping,if every c.e. degree x with 0ping *** the present paper,we show that PC is not closed under the join op... 详细信息

A computably enumerable (c.e.,for short)degree a is called plus cupping,if every c.e. degree x with 0ping *** the present paper,we show that PC is not closed under the join operation ∨ by constructing two plus cupping degrees which join to a high degree. So by the Harringtons noncupping theorem,PC is not an ideal of ε.

关键词： computably enumerable set Turing degree definability.

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：