检索结果-南通市图书馆

Effective capacity region of two-user opportunistic spectrum access

在线全文

学校读者我要写书评

暂无评论

Science china(Information Sciences) 2011年第9期54卷 1928-1937页

作者： XU YuHua,WANG JinLong & WU QiHui institute of Communications Engineering,PLA University of Science and Technology,nanjing 210007,china 1. institute of Communications Engineering PLA University of Science and Technology Nanjing 210007 China

The effective capacity region of the two-user opportunistic spectrum access (OSA) system in Rayleigh fading environment is derived in this *** OSA is a contemporary research topic,little attention has been given to the capacity analysis under quality-of-service (QoS) ***,we use the effective capacity,which is a powerful tool to analyze the QoS requirements in wireless communication systems,to study the sustainable packet arrival rate of the secondary users while meeting statistical QoS *** derive the effective capacity region of the two-user OSA system and propose a method to obtain the capacity region *** addition,by combining the finite state channel model and the activity of the primary user,an extended finite state channel model for the two-user OSA system is also proposed.

关键词： cognitive radio opportunistic spectrum access effective capacity

Sustainable Nutrient Management in Chinese Agriculture: Challenges and Perspective

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Pedosphere 2006年第2期16卷 253-263页

作者： GAO Chao SUN Bo ZHANG Tao-Lin Department of Geography Nanjing University Nanjing 210093 （China）. institute of Soil Science Chinese Academy of Sciences Nanjing 2100（78 （China）

china has to raise agricultural productivity in its limited and shrinking farmland to guarantee food security for its huge and ever-growing population. Sustainable soil nutrient management is of paramount importance to the world's most populous country. Critical challenges the country is facing in sustaining soil fertility and in alleviating the hazardous impact of intensive fertilizer use are discussed in this paper. It is emphatically pointed out that national strategies as well as area-specific action plans with respect to scientific nutrient management are urgently needed to balance productivity and sustainability in the future. Relevant proposals for addressing those challenges are also presented.

关键词： china food security nutrient management soil fertility water quality

Gas formation mechanism of marine carbonate source rocks in china

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2005年第4期48卷 441-453页

作者： ZHAO Wenzhi1, WANG Zhaoyun1, HE Haiqing2, ZHANG Mingjie3. WANG Hongjun1, WANG Yunpeng4 & QIN Yong5 1. Research institute of Petroleum Exploration & Development, Petrochina, Beijing 100083. china 2. Petrochina Exploration & Production, Beijing 100011, china 3. Department of Geology, Lanzhou University, Lanzhou 73.000, china 4. Guangzhou Geochemical institute, Chinese Academy of Sciences, Guangzhou 510640, china 5. china University of Mining and Technology, Xuzhou 221000, china 1. Research institute of Petroleum Exploration & Development 100083 PetroChinaBeijin China 2. Petrochina Exploration & Production 100011 Beijing China 3. Department of Geology Lanzhou University 730000 Lanzhou China 4. Guangzhou Geochemical institute Chinese Academy of Sciences 510640 Guangzhou China 5. china University of Mining and Technology 221000 Xuzhou China

By breaking through the conventional ideology on the study of gas-formation mechanism of source rocks which focused on merely the characteristics of source rocks them- selves, and based on the development and distribution characteristics of marine carbonate source rocks in the medium-to-bottom parts of the Chinese superimposed sedimentary basins as well as various processes in the course of gas generation and reservoir forming, the complex hydrocarbon-generating model of carbonates is established. Such a model concerns not only the “three-stage” gas formation characteristics of carbonates, but also the gas generation process due to a thermal cracking of oil and the re-generation process of gas from heated secondary organic matters during the gas-generation and reservoir-forming course. The high-quality hy- drocarbon generating matter of marine carbonate source rocks determined a high gas-oil ratio and tended to form paleo-oil-reservoirs, representing an enrichment process of organic matters. The thermal cracking of oil in palaeo-oil-reservoirs is an important means for the effective forma- tion of gas reservoirs. The secondary organic matters in carbonate reservoirs may regenerate gas after a secondary deep burial, thus becoming an effective gas source.

关键词： carbonate, three-stage hydrocarbon generation, inhibitive effect of maturity, oil-cracking gas, second-ary asphalt gas.

Preliminary study on assessment of nutrient transport in the Taihu Basin based on SWAT modeling

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2006年第z1期49卷 135-145页

作者： LAI Geying, YU Ge & GUI Feng nanjing institute of Geography & Limnology, Chinese Academy of Sciences, nanjing 210008, {3. The Graduate School of the Chinese Academy of Sciences, Beijing 10003., {3. Key Lab of Poyang Lake Ecological Environment and Resource Development, Jiangxi Normal University, Nanchang 3.0027, {3. 1. nanjing institute of Geography & Limnology Chinese Academy of Sciences Nanjing 210008 China2. The Graduate School of the Chinese Academy of Sciences Beijing 100039 China3. Key Lab of Poyang Lake Ecological Environment and Resource Development Jiangxi Normal University Nanchang 330027 China

With the Taihu Basin as a study area, using the spatially distributed and mechanism-based SWAT model, preliminary simulations of nutrient transport in the Taihu Basin during the period of 1995～2002 has been carried out. The topography, soil, meteorology and land use with industrial point pollution discharge, the loss of agricultural fertilizers, urban sewerage, and livestock drainages were all considered in the boundary conditions of the simulations. The model was calibrated and validated against water quality monitoring data from 2001 to 2002. The results show that the annual total productions of nitrogen (TN) and phosphorus (TP) into Lake Taihu are 40000t and 2000t respectively. Nutrient from the Huxi Region is a major resource for Lake Taihu. The non-point source (surface source) pollution is the main form of catchment sources of nutrients into Lake Taihu,occupied TN 53. and TP 56% respectively. TN and TP nutrients from industrial point pollution discharge are 3.% and 16%, and sewerage in both forms of point source and non-point source are TN 3.% and TP 47%. Both the loss of agricultural fertilizers and livestock drainages from the catchment should be paid more attention as an important nutrient source. The results also show that SWAT is an effective model for the simulation of temporally and spatially nutrient changes and for the assessment of the trends in a catchment scale.

关键词： Taihu Basin, nutrients, catchment resource inputs, SWAT model, simulation.

Mapping of QTL for Phenol Reaction Using Chromosome Segment Substitution Lines in Rice （Oryza sativa L.）

在线全文

学校读者我要写书评

暂无评论

Mapping of QTL for Phenol Reaction Using Chromosome Segment ...

江苏省遗传学会第七届二次代表大会暨学术研讨会

作者： YANG De-wei1,2, ZHU Wen-yin2, LIN Jing2, ZHAO Ling2, ZHANG Ya-dong2, ZHU Zhen2, CHEN Tao2, Wang Cai-lin2① (1.Agricultural College , nanjing Agricultural University , nanjing 210095, china 2.{3. of Food Crops, jiangsu Academy of Agricultural Sciences, jiangsu High quality Rice Research&Development Center, nanjing 210014, china )

The phenol reaction on rice seed is one of the indexes differentiated japonica from indica. In this paper, chromosome segment substitution lines（CSSLs）, derived from 93.1/ Nipponbare with 93.1 as the recurrent parent, were experimented for the phenol reaction, and three QTLs were analyzed with the substitution mapping. The results showed that four chromosome segment substitution lines （CSSLs） were 4 classes and the rest were 0 to 1 class. Each CSSL had one introgressed segment coming from Nipponbare;three CSSLs on rice chromosome 2, two CSSLs on rice chromosome 4 and three CSSLs on rice chromosome 7 had one introgressed segments, respectively. The genetic distance of the eight introgressed segment were 24.9cM、3..8cM、 9.7cM、 9.5cM、22.7cM、16.7cM、22.2cM and 13.0cM , respectively. Three QTLs for the phenol reaction were identified. qPH2 was mapped in the region of RM406 and RM240, which was 12.9cM in genetic distance on rice chromosome 2. qPH4-1 was mapped in the region of RM280 and RM5709, which was 9.5cM in genetic distance on rice chromosome 4. qPH7 was mapped in the region of RM11 and RM6574, which was 16.0cM in genetic distance on rice chromosome 7. The QTL for the phenol reaction on rice seed can be mapped primely using chromosome segment substitution lines. Mapping of the QTL has laid a foundation for fine mapping and cloning of the QTL in rice.

关键词： Rice chromosome segment substitution lines(CSSLs) substitution mapping phenol reaction

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

人之卓越的丧失与制造平庸的教育

教育发展研究 2011年第21期31卷 32-36页

作者：章乐南京师范大学道德教育研究所南京210097

人之卓越就是实现人之为人的内在要求,在现代条件下,它意味着人要超越低层次的需要,走向高层次的需要,即"自我超越"。人之卓越不是一种品质,而是实现活动。物质主义造成了卓越的扭曲,官僚体系束缚了对卓越的追求,相对主义带来了自我的封... 详细信息

人之卓越就是实现人之为人的内在要求,在现代条件下,它意味着人要超越低层次的需要,走向高层次的需要,即"自我超越"。人之卓越不是一种品质,而是实现活动。物质主义造成了卓越的扭曲,官僚体系束缚了对卓越的追求,相对主义带来了自我的封闭,民主政体在某种程度上造成了大众的平庸,这些都是造成人之卓越丧失的现代根源。让学生接受卓越的教育,学过卓越的生活,对他们的卓越表现给予承认,并培养他们苏格拉底式反思的品质是可能的教育出路。

关键词：人之卓越

Fine Mapping and Candidate Gene Analysis of a Green-revertible Albino Gene gra(t) in Rice (Oryza sativa L.)

在线全文

学校读者我要写书评

暂无评论

Fine Mapping and Candidate Gene Analysis of a Green-revertib...

FORTRAN 2000异常处理机制的研究

2009中国作物学会学术年会

作者： Chen Tao, Zhang Ya-Dong, Zhao Ling, Zhu Zhen, Lin Jing, Zhang Suo-Bing, Wang Cai-Lin* (institute of Food Crops, jiangsu Academy of Agricultural Sciences, jiangsu High {3. Rice R&D Center, nanjing Branch of china National Center for Rice Improvement, nanjing 210014, china)

Green-revertible albino is a novel type of chlorophyll deficiency in rice (Oryza sativa L.), which is helpful for further research in chlorophyll synthesis and chloroplast development to illuminate their

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

计算机科学 2004年第3期31卷 173-175页

作者：鞠小林徐宝文东南大学计算机科学与工程系

异常处理是现代程序设计语言的一个重要特征,它为检测和恢复软件系统在运行时的错误、构建系统的容错处理提供了强有力的支持。本文分析了FORTRAN 2000的异常处理机制,并提出一种扩充方案,引入用户定义异常和异常处理区的概念,改进了异... 详细信息

异常处理是现代程序设计语言的一个重要特征,它为检测和恢复软件系统在运行时的错误、构建系统的容错处理提供了强有力的支持。本文分析了FORTRAN 2000的异常处理机制,并提出一种扩充方案,引入用户定义异常和异常处理区的概念,改进了异常的传播机制,从而使FORTRAN编程更好地实现普通代码和异常处理代码的分离,提高了程序的可读性和可维护性。

关键词：程序设计语言 FORTRAN 2000 异常处理机制程序代码缺省处理程序

Preparation of microencapsulatedα-olefin drag reducing polymer used in oil pipeline transportation

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2011年第1期8卷 99-107页

作者： Li Bing Xing Wenguo Dong Guilin Chen Xiangjun Zhou Ningning Qin Zhanbo Zhang Changqiao School of Chemistry and Chemical Engineering Shandong UniversityShandong 250061China Linyi institute of Product quality Supervision and Inspection Shandong 276004China Shandong institute of Metrology Shandong 250014China Shandong quality Certification Centre Shandong 250014China

Microcapsules containing oil drag-reducing polymer particles were prepared by melting-scattering and condensing of polyethylene wax,in-situ polymerization of urea and formaldehyde,and interfacial polymerization of styrene *** related processes were studied by a molecular dynamics simulation method,and molecular design of microcapsule isolation agent was carried out on the basis of the *** technologies for preparing microencapsulated oil drag-reducing polymer particles were compared and the circulation drag reducing efficiency of the microencapsulated polymer particles was evaluated based on the characterization results and their dissolution *** design of a microcapsule isolation agent suggests that a-olefin polymer particles can be stably dispersed in water by using long-chain alkyl sodium salt surfactant which can prevent the agglomeration ofα-olefin polymer *** results of simulation of the adsorption process shows that the amount of alkyl sodium salt surfactant can directly affect the stability of microencapsulatedα-olefin polymer particles, and there must be a minimum critical amount of *** characterization of the morphology by Scanning Electron Microscopy（SEM） and comparison of the static pressure stability,especially the conditions of reaction and technological control of microcapsules with different shell materials,microencapsulation of a-olefin polymer particles with poly-（urea-formaldehyde） as shell material was selected as the optimum scheme,because it can react under mild conditions and its technological process can be controlled in a large *** relationship of drag reducing rate and dissolving time of microcapsules showed that the formation of microcapsules did not affect the maximum drag reducing rate,and the drag reducing rate of each sample can reach about 3.%along with the dissolving time,*** did not affect the drag reducing property ofα-olefin polymer.

关键词： α-olefin polymer molecular design coating material microcapsule preparation stability and solubility drag reducing property