检索结果-南通市图书馆

Integrating MODFLOW and GIS technologies for assessing impacts of irrigation management and groundwater use in the Hetao Irrigation District,Yellow River basin

引用

Science china(Technological Sciences) 2009年第11期52卷 3257-3263页

作者： XU Xu1,2, HUANG GuanHua1,2 & QU ZhongYi3 1 Center for agriculture Water Research, china Agricultural university, beijing 100083, china 2 Chinese-Israeli International Center for Research and Training in agriculture, china Agricultural university, beijing 100083, china 3 Water Conservancy and Civil Engineering College, Inner Mongolia Agricultural university, Hohhot 010018, china 1. Center for agriculture Water Research China Agricultural University Beijing 100083 China 2. Chinese-Israeli International Center for Research and Training in agriculture China Agricultural University Beijing 100083 China 3. Water Conservancy and Civil Engineering College Inner Mongolia Agricultural University Hohhot 010018 China

Due to severe water scarcity, water resources used in agricultural sector have been reduced markedly in Hetao irrigation district. Application of water-saving practices (WSPs) is required for the sustainable agricultural development. The human activities including WSPs and increase of groundwater abstraction can lower down the groundwater table, which is helpful to the salinity control. Meanwhile, an excessively large groundwater table depth may result in negative impact on crop growth and fragile ecological environment. In this paper, the Jiefangzha irrigation system in Hetao irrigation district was selected as a typical area, a groundwater flow model based on ArcInfo Geographic Information System (GIS) was developed and implemented to quantify the effect of human activities on the groundwater system in this area. The preand post-processing of model data was performed efficiently by using the available GIS tools. The time-variant data in boundary conditions was further edited in Microsoft Excel with programs of Visual Basic for Application (VBA). The model was calibrated and validated with independent data sets. Application of the model indicated that it can well describe the effect of human activities on groundwater dynamics in Jiefangzha irrigation system.

关键词： groundwater flow modeling MODFLOW GIS water-saving practices irrigation district

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

STUDY ON THE REAR CAPACITY OF DEPOSITS USING ELECTROLESS NICKEL DEPOSITION AND ELECTROPLATE CHROMIUM

引用

Acta Metallurgica Sinica(English Letters) 1999年第5期12卷 777-781页

作者： S.Y.Hu Collge of Mechanical Engineering, china agriculture university (East Campus), beijing 100083, china

The comparison study of the relations between the hardness, wear capacity and heat treatment temperature of the electroless nickel deposition with the electroplating deposits of chromium were conducted .The results showed that the hardness and wear capacity of the electroplate technology were superior than that of electroless in general cases, but with the raising of the heat treatment temperature, the hardness and wear capacity of the samples treated by electroless deposition technology were superior obviously than that of electroplate.

关键词： electroless nickel deposition electroplating chromium wear capacity

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

Induction of phenylalanine ammonia-lyase and lipoxygenase in cotton seedlings by mechanical wounding and aphid infestation

引用

Progress in Natural Science:Materials International 2005年第5期15卷 419-423页

作者： QIN Qiuju, SHI Xueyan, LIANG Pei and GAO Xiwu*(Department of Entomology, china agriculture university, beijing 100094, china) Department of Entomology China Agriculture University Beijing 100094 China

It has been suggested that infestation of plants causes increases in the activities of phenylalanine ammonia-lyase (PAL) and lipoxygenase (LOX), key enzymes in the phenolic compounds synthesis pathway and the octadecanoid pathway, respectively. The purpose of this work is to investigate whether the infestation of cotton aphid (Aphis gossypii) and mechanical wound can cause the induction of PAL and LOX activities in cotton seedlings, and whether the induction occurs in healthy seedlings growing nearby the attacked ones. The specific activities of PAL and LOX were measured using spectrophotometric method after aphid infestation and mechanical wounding. Result indicated that PAL activity and LOX activity were greatly induced by mechanical wounding and aphid infestation in cotton seedlings. The induction of PAL and LOX occurred not only in wounded and infested seedlings but also in intact healthy seedlings growing nearby. After exposed to the aphid infestation-induced volatiles, the specific activity of PAL in cotton seedlings increased by 6% at 24 h, 80% at 48 h, 235% at 72 h compared to the control, and the specific activity of LOX increased by 18% at 24 h, 34% at 48 h, 24% at 72 h, respectively. In comparison, the specific activity of PAL in unwounded seedlings exposed to wound-induced volatiles increased by 0.0 at 24 h, 200% at 48 h, 164% at 72 h, respectively and the specific activity of LOX increased by 28% at 24 h, 37% at 48 h, 8% at 72 h, respectively. It suggests that the induced volatiles are involved in plant-plant communication as airborne transferred signals.

关键词： phenylalanine ammonia-lyase lipoxygenase cotton aphid mechanical damage cotton plants.

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

Systemic PCD occurs in TMV-tomato interaction

引用

Science china(Life Sciences) 2008年第11期51卷 1009-1019页

作者： ZHOU ShuMin, LIU WenNa, KONG LinAn & WANG Mao College of Biological Sciences, china agriculture university, beijing 100094, china 1. College of Biological Sciences China Agriculture University Beijing 100094 China

In hypersensitive response (HR), programmed cell death (PCD) is reported as a powerful defense mechanism in plant immune responses to pathogen. However, little is known about the PCD in sys-temic acquired resistance (SAR). Using tobacco mosaic virus (TMV) to infect the tomato (Lycopersicon esculentum cv. Jiafen 16) we found that localized TMV-infection could induce cell death in the uninoculated parts of the tomatoes, where the enzyme-linked immunosorbent assay (ELISA) showed no spreading virus. The biological and molecular characterization of this cell death was shown as fol-lowing: chromatin condensed and formed peripheral conglomeration in nuclei; cell nucleus were TUNEL positive labeled; genomic DNA was fragmented and showed DNA laddering; mitochondria and chloroplast were disrupted; tonoplast and plasma membrane were shrunk and degradated. These re-sults suggested that with an absence of TMV spread, the local TMV-infection on certain tomato leaves could induce systemic PCD in the root-tips, stem-apices and uninoculated leaves. The systemic PCD has various initiation and synchronization in such tissues and is distinct in inducement and exhibition from HR-PCD and SAR.

关键词： programmed cell death systemic PCD TUNEL assay DNA ladder TMV tomato

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

Research progress on electrical signals in higher plants

引用

Progress in Natural Science:Materials International 2009年第5期19卷 531-541页

作者： Xiaofei Yana, Zhongyi Wang a, Lan Huang a, Cheng Wang b, Ruifeng Hou b, Zhilong Xu b, Xiaojun Qiao b a College of Information and Electrical Engineering, china Agricultural university, beijing 100083, china b National Engineering Research Center for Information Technology in agriculture, beijing 100097, china [a]College of Information and Electrical Engineering China Agricultural University Beijing 100083 China [b]National Engineering Research Center for Information Technology in Agriculture Beijing 100097 China

This review introduces the characteristics of electrical signals in higher plants and their corresponding physiological significance, and describes in detail the impact of environmental factors (e.g. light and temperature) on the electrical potential of the plants. Also, we evaluate the measurement techniques used for electrical signals in plants, including intracellular measurement, extracellular measurement, measurement of the ion channel based on the patch-clamp technique and on the non-invasive microelectrode vibrating probe technique. We also give a brief review of the applications of these methods for investigating electrical signals in plants. The ionic mechanism of electrical activity in plants is then discussed in terms of environmental response in higher plants, and this is used to provide a theoretical basis for quantitative description of the electrical signals in plants. A model for interpretation of the electrical signal mechanisms in higher plants is discussed, but further experiments are required for the verification of this model.

关键词： Ion channel Temperature-induced Light-induced Ion mechanism Measurement technology

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

Effects of nitrogen ion implantation on Ca^(2+) concentration and membrane potential of pollen cell

引用

Chinese Science Bulletin 2001年第20期46卷 1691-1693页

作者： HUANG Zhonglian, JING Yanping, ZHU Guoli, LU Ting, ZHOU Hongyu & REN Haiyun1. Key Laboratory of Cell Proliferation and Regulation Biology of the Ministry of Education, beijing Normal university, beijing 100875, china 2. Key Laboratory of Plant Physiology and Biochemistry of the Ministry of agriculture, china agriculture university, beijing 100094, china 3. Institution of Low Energy Nuclear Physics, beijing Normal university, beijing 100875, china Key Laboratory of Cell Proliferation Regulation Biology of Min. of Educ. Beijing Normal University Beijing 100875 China

The effects of low energy nitrogen ion implantation on Ca2+ concentration and membrane potential of illy (Mum davidii Duch) pollen cell have been studied. The results showed that the Ca2+ concentration was increased when pollen grain was implanted by nitrogen ion with energy 100 keV and dose 1013 ions/cm2. However, the increase of Ca2+ concentration was partly inhibited by the addition of Ca2+ channel inhibitor depending on dose. And nitrogen ion implantation caused depolarization of pollen cell membrane potential. In other words, membrane potential was increased, but the effect decreased by adding Ca2+ channel inhibitor. However, it was still significantly higher than the membrane potential of control cells. It was indicated that the depolarization of cell membrane potential opened the calcium channel on the membrane that caused the increasing of intracel-lular calcium concentration. This might be an earlier step of the effect of low energy nitrogen ion implantation on pollen germination.

关键词： nitrogen ion implantation lily pollen calcium concentration membrane potential.

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

The Status of Organochlorine Pesticides Pollution in Hubei Section of the Yangtze River

引用

地学前缘 2009年第S1期16卷 81-82页

作者： Chen Liu,Liyuan Guo School of the Earth Sciences and Resources,china university of Geosciences(beijing),beijing 100083,china.

The Organochlorine Pesticides(OCPs),such as hexachlorocyclohexane(HCH)and dichlorodiphenyltrichloro ethane(DDT),are well known as typical persistent organic pollutions(POPs).They were worldwide used several decades ago,even today in some *** the water resource is very important in natural environments and essential to agriculture,the pollution of OCPs in water has emerged as worldwide environmental problem. Wuhan section of the Yangtze River is the drinking water source of Wuhan area in Hubei *** addition,Hubei province is an important production base of grain,cotton,oil and *** the rapid development of industry and mass-use of OCPs

关键词： organochlorine pesticides Yangtze River water residues

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

Ramet population ecology of Panicum virgatum in the field–Competitively random growth of ramets and foraging behavior of ramet populations

引用

Progress in Natural Science:Materials International 2008年第7期18卷 901-906页

作者： Xinguo Yang a,*, Tianlong Wu b, Xu Chengb a College of Resources and Environmental Sciences, china Agricultural university, beijing 100193, P.R. china b College of agriculture and Biotechnology, china Agricultural university, beijing 100193, P.R. china College of Resources and Environmental Sciences China Agricultural University Beijing 100193 P.R. China College of agriculture and Biotechnology China Agricultural University Beijing 100193 P.R. China

The authors investigated the heterogeneous size patterns and dynamic growth of the ramet population of Panicum virgatum, a clonal caespitose plant, limited to the space occupied by a ramet bunch and the time of the ramet yearly life cycle, to understand the ecology of clonal caespitose plants in the field, where the ramet bunch generally consisted of more than one genet. Dynamic life tables for ramet populations were established by the replacement of living ramets at the present time with "dead" ones in past time. These tables revealed stable coexisting patterns of isometric and allometric growing processes of ramets in mass and height respectively, which approximately followed the historic trajectory of a density-independent population. The ecology of clonal caespitose plants is further discussed based on the competitively random growth of ramet individuals, including the scale of foraging behavior. In the field, the ramet population ecol- ogy of switchgrass may be a statistical result of competitively random growth of ramet individuals. The foraging behavior of a ramet population could then be presented as a process in which ramet individuals competed with each other for light and grew randomly, while at the same time a relatively stable dynamic growth pattern was apparent at the level of the ramet population, and the functional leaves were placed properly in time and space.

关键词： Caespitose clone Ramet population Panicum virgatum Life table Phenotypic plasticity Foraging behavior

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

The action and analysis of magnetic field on the lubricants and wear products in the process of wearing

引用

Science china Mathematics 2001年第S1期44卷 267-272页

作者： ZHOU Qiang XU Ruiqing Mechanical Engineering College, china agriculture university, beijing 100083, china china Agr Univ Mech Engn Coll Beijing 100083 Peoples R China

The magnetic field is an important factor in the conditioning and controlling tribologicalproperty. This paper analyzes and describes the physical effects and chemical natures of magneticfield to affect the friction, wear and lubrication, and characterize the tribochemical effect of mag-netic field on WRL lubricant by infrared(IR) spectrum method. At same time, the tribological prop-erty of WRL lubricant was examined by using the reciprocating friction-wear tester of NG-x type inthe condition of magnetic field. The results show that the present of magnetic field can decreasethe friction coefficient(f) and wear weight(W), even realize the zero-wear testing situation.

关键词： magnetic field friction and wear lubricant boundary film micro-particles alkylated metal micro-debris

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

The boundary of palaearctic and oriental realms in western china

引用

Progress in Natural Science:Materials International 2008年第7期18卷 833-841页

作者： Ling Chen a,b,c, Yanling Songd,*, Shufang Xu e a Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810001, china b Graduate university of the Chinese Academy of Sciences, beijing 100039, china c National Science Foundation of china, beijing 100085, china d Institute of Zoology, Chinese Academy of Sciences, beijing 100101, china e beijing Academy of agriculture and Forestry Sciences, beijing 100097, china Northwest Institute of Plateau Biology Chinese Academy of Sciences Xining 810001 China Graduate university of the Chinese Academy of Sciences Beijing 100039 China National Science Foundation of china Beijing 100085 China Institute of Zoology Chinese Academy of Sciences Beijing 100101 China beijing Academy of agriculture and Forestry Sciences Beijing 100097 China

In the world-wide zoogeographic division, there has been no consentaneous understanding about the delimitation between palaearctic and oriental realms in western china. In this study, we will discuss the division based on amphibian distribution in Shaanxi, Gansu, Sichuan, Yunnan, and Tibet according to species coefficient similarity between each zoogeographic province. The results show that the northern border lies from Qinling Mountains–Feng Xian (Shaanxi)–Debu (Gansu)–Aba (Sichuan)–Batang–Bomi (Tibet), to Linzhi districts, and the southern border is from Taibai–Feng Xian in Shaanxi–Wen Xian (Gansu)–Songpan–Kangding–Daocheng (Sichuan), to Zhongdian–Gongshan in Yunnan, and westward to Motuo and Bomi district in Tibet.

关键词： Amphibian Zoogeography Palaearctic Oriental Hengduan Mt.

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

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：