膜下滴灌节水技术在农业中的应用与推广

我国是农业大国，全国需要灌溉的土地约有19．5亿亩，灌溉用水约为3900多亿立方米。传统农业采用的灌溉方式。都是“浇地”不“浇作物”。随着水资源日益短缺的严峻形势，农业节水灌溉技术已迅速发展起来，特别是膜下滴灌技术的应用，给农业生产带来了相当的经济效益。是很值得推广的。     

我国灌溉农田高效用水研究进展评述

在农业水利灌溉领域,论述我国水资源现状和农业用水状况以及我国对于高效农业的研究进展。针对我国人口与水、土地等资源的矛盾问题,提出因地制宜地农业灌溉方法。指出了在我国农业节水灌溉的现状和推广中出现的问题,并针对出现的一系列问题,提出了加强宣传力度,提高节水意识、加强国家引导力度、加强节水灌溉新技术的应用等对策,以促进我国高灌溉农田高效用水的进展。     

现阶段我国农业节水灌溉实用技术及其发展趋势

我国水资源短缺现象严重,发展农业节水灌溉技术很是必要。本文对现阶段我国农业节水灌溉实用技术进行了介绍和分析,并对今后农业节水灌溉技术的发展进行了展望和分析,以期为大力推广节水灌溉技术,发展节水农业,构建节水型社会提供参考。     

许昌花木基地节水灌溉模式及效益分析

许昌市花木节水灌溉示范区,选择多种现代节水灌溉技术,对不同种类花木的需水规律、技术模式、管理模式、产生的效益进行了深入的分析研究,对提高花木基地的水资源承载能力,改善农业基础生产条件等多方面具有重要意义.     

农业节水灌溉现状及其发展趋势

在分析我国实施农业节水灌溉必要性的基础上,论述了目前我国农业主要采取的节水灌溉技术及其优缺点,并对农业未来的发展趋势进行了展望,即继续完善农业田间工程配套技术建设,在农业管理中采用信息化管理,并将农业节水与工程节水技术相结合,利用先进的灌溉管理体制来实现农业节水的高效快速发展。     

农业灌溉泵站日常运行与维护管理研究

浇灌泵站建筑物的日常运行和维护管理对于提高区域农业的防洪能力必不可少，它们不仅能够满足人们的基本需求，还能够为农村发展提供强有力的支撑。对于我国区域农业水利灌溉和防洪而言，灌溉泵站的日常运行和维护管理至关重要，但是仍然存在一些问题，本文将对这些问题进行深入探讨，并提出有效的解决方案，以期达到更好的灌溉效果。     

自动化技术在节水灌溉中的应用——以西北农业耕作区为例

在西北农业耕作区,能自动收集各种农业灌溉信息,实现节水灌溉,应是西北现代化节水灌溉技术的主要发展方向,而实现这一技术的关键就在于灌溉自动控制技术的相关设计和实施。本文尝试根据我国西北地区农业节水灌溉的问题,简析节水灌溉自动化控制实现的可行性。     

我国农业节水灌溉现状与对策建议

近些年我国农业节水灌溉有了显著的发展,但相比其他国家来说,我国还有相当大的差距.在我国严峻的水资源形势下,发展节水灌溉具有重要的现实意义和历史意义.通过分析目前我国农业节水灌溉的现状,指出了节水灌溉推广中遇到的问题和困难,最后提出了针对性的对策建议.     

农业灌溉自动控制系统研究

所谓灌溉自动化，即在农业生产过程中，使用一定的设备、元件，通过适当的灌溉方式，在准确地分析各种生产要素的基础上，对衣作物的不同生长阶段分别进行定时、定量的自动、半自动灌溉。应用节水型农业灌溉技术是今后发展的必然趋势，研究自动化控制灌溉用水量是发展节水农业的先决条件。     

基层节水灌溉技术推广中存在的问题及改善策略

面对全球水资源日益缺乏的现状,我国在水资源利用方面提倡节约用水,在节约用水方面,主要表现在农业的灌溉上。我国的土地面积大,农业用水量大,在农业用水上实行节水灌溉是发展的主要方向。我国在实行基层节水灌溉技术推广过程中存在很多的问题,阻碍了灌溉技术的发展,本文对此做出分析,并制定出改善的策略。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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