Transient stability simulation methods incorporating PMU measurements

Incorporating the PMU measurements information in transient stability simulation can increase computing speed and enhance accuracy in the time domain simulation. Based on the conventional alternating iteration technique, this paper presents two simulation methods combined with the PMU measurements information, in which the number of differential algebraic equations is reduced and so is the computational scale. The proposed methods have been tested and compared with the conventional method using the New England 10 machine 39 bus system and IEEE 50 machine 145 bus system. The cases with errors of the dynamic model parameter and PMU have been also simulated and discussed. The simulation results demonstrate the effectiveness of the presented methods.     

石斛属植物种质资源鉴定及指纹图谱应用研究进展

为了鉴别石斛属植物不同种质,区分石斛伪品劣品,笔者综述了传统的形态学与显微鉴定、细胞学、孢粉学以及指纹图谱技术（化学指纹图谱和DNA指纹图谱）的特点,及其在石斛属植物种质资源鉴定中的应用,发现指纹图谱技术对石斛属植物的种源和道地性鉴定以及石斛类药材质量控制十分有效,但指纹图谱标准和评价体系还存在不足,今后还需在野生石斛资源的评价与合理利用、指纹图谱与药理作用相关性、遗传改良和基因克隆等方面开展深入研究。     

土壤氮素矿化研究进展

总结了现阶段土壤中有机氮矿化的研究成果，详细阐述了影响有机氮矿化的因素：温度、水分均对氮矿化量、矿化速率有影响，且二者存在明显交互作用；耕作制度通过改变土壤的物理性质，也导致了土壤中氮矿化过程发生变化；施用不同肥料对氮矿化过程的影响也不同；土壤预处理等均会对氮矿化过程产生影响。该文还归纳了目前在研究土壤氮矿化过程中的主要方法及氮素矿化模型，并剖析了各种研究方法的适用条件及各种模型的应用范围。     

A Survey of Power Flow Tracing Algorithm

Competition in the electricity markets requires identifying the responsibility in the use of transmission networks or the associated effects. Power Flow Tracing algorithms have been developed recently to enhance the transparence of transmission system. This paper focuses on power flow tracing procedures and provides a detailed comparison of three classified algorithms: 1) power flow tracing based methods; 2) current tracing based methods; and 3) power flow analytic methods. The advantage and disadvantage of each method are discussed. Finally, the potential applications and development of the methodology is presented for furthermore research.     

Development and Research of Forest Tourism from the Perspective of Forest Experience

Forest experience is an important scale for measuring the development degree of forest tourism,and also an indispensable part of forest tounsm.Domestic theoretical and practical researches on forest experience and forest tourism have been less reported,forest tounsm development and research from the perspective of forest experience have remained in the exploration stage,and researches on natural education and forest culture have also been just initiated.This paper explored problems of current forest tourism development from three perspectives of forest experience,i.e.environmental index,experience content and facility service.By applying scientific development and marketing methods,and combining with traditional health-care culture,forest tourism development spaces could be expanded.Finally,the paper proposed to establish forest ecological monitoring system and enrich forest experience projects to provide visitors forest tounsm expenence with high additional value and satisfaction degree.     

检验功能性提取物抗过敏活性方法综述

阐述了过敏反应的原因、抗过敏活性成分的作用机制,侧重对近年来检验抗过敏食品活性方法进行了综述。过敏性疾病对过敏人群的正常生活造成了较为严重的困扰,抑制过敏发病率,开发新型抗过敏功能性食品成为近年来的热门方向。如今,研究抗过敏活性的方法不断增加完善,为需要研究抗过敏活性方法的研究者提供参考。     

基因型与环境互作研究的新进展

研究基因型-环境互作是进行遗传分析、品种评价的一个重要环节。Freeman(1973)、Hill(1975)和 Westcott(1986)对用于这一领域的研究方法进行了总结回顾。本文将系统地阐述其中研究非线性基因型-环境互作的方法的基本理论及运用思想。包括非线性回归分析、聚类分析、主分量分析、偶图法、多维标度法和主坐标分析及对应分析。     

Evolutionary Programming Solution of Economic Dispatch with Valve Point Loading

This paper describes an application of evolutionary programming (EP) to economic dispatch with valve point loading.Some technical problems (representations of candidate solutions,evaluation function,mutation operator) have been solved to expand the applica be prospects of the computatimal methods of economic dispatch.The proposal method is applied to a 6 bus 3 generator system and compared with the genetic algorithm(GA).Numerical results demonstrate the validity and effectiveness.     

Square Pegs and Round Holes: Can the Economic Paradigm be Used to Value the Wilderness?

ABSTRACT This paper examines whether economic valuation methods are capable of meaningfully measuring the value of the wilderness in monetary terms. Although non-monetary valuation methods are often important in policy making arenas, this paper focuses on monetary methods. Three questions are examined to determine if these economic valuation methods can contribute to the development of wilderness policy. First, are the valuation methods which have been developed by economists capable of expressing in dollar terms the value of all the services which the wilderness supplies? Second, if these valuation methods are not capable of eliciting all the relevant values, are they still useful for public policy purposes? Third, can the valuation methods be modified or can new methods be developed which can measure some of the values which have not been captured by the previously employed methods? The paper reviews existing valuation methods according to these criteria and finds that the ability to value the wilderness is limited by the shortcomings of currently employed techniques. Refinements to existing methods and potential new methods are suggested to further the valuation process.     

植物功能基因组研究主要方法与技术及在大豆上的应用

植物基因组研究已经进入了功能基因组学的新阶段,对基因功能的研究已转向对多基因的高通量、大规模和批量分析,一些新的方法和技术相继建立。大豆是世界上重要的粮、油、饲兼用作物,功能基因组学研究起步较晚,但发展迅速。本文概述了植物基因功能研究的主要内容与方法如基因序列比对、基因组序列测定和反向遗传学方法等及在大豆研究中的应用;论述了主要技术如表达序列标签(EST)、基因表达连续分析法(SAGE)、cDNA微阵列、Tilling技术、RNA干涉技术(RNAi)等及在大豆研究中的应用。最后介绍了基因组研究相关的数据库。     

Multifunctionality and agrarian transition in alternative agro‐food production in the global South: The case of organic shrimp certification in the Mekong Delta,Vietnam

Processes of globalisation in the conventional food provision system have had widespread negative impacts on small‐scale farmers. Yet, alternative food networks, which are characterised by more sustainable production/consumption practices and fairer trade relations, have increasingly been ‘going global’ and, in the process, have been integrating small‐scale farms in the South. One such high‐value export‐led commodity is certified organic shrimp. International third‐party certification schemes are becoming popular as a tool to verify the intangible attributes of such commodities. Using concepts of multifunctionality and agrarian change, this paper examines the implications of introducing an international environmental certification programme to a site where the ‘peasantry’ has been preserved and has limited integration in the global agro‐food system. Drawing on a case study that examines the first certified organic shrimp production project in Vietnam, this paper concludes that the current movement towards post‐productivism in the global North has potential to keep local farming practices in the global South by justifying the value of peasant‐like production methods through international certification. As a result, the development path of agrarian transition might be reshaped into a form not necessarily pursuing industrialisation. This leads to the new interpretation of pre‐ and post‐productivism beyond the North and South divide.     

Advances in Monitorinq Methods of Downward Surface Net Radiation

Downward surface net radiation,the net energy of the earth's surface obtained through shortwave and longwave radiation process,is the main driving force for material and energy cycle in the whole earth system.In this study,the main research results of monitoring methods of downward surface net radiation at home and abroad in recent decades have been summarized,and main remote sensing radiation products produced according to various sensors have been introduced.Moreover,the monitoring methods of downward shortwave and long-wave radiation have been discussed,and their principles,advantages and disadvantages have been analyzed to provide scientific references for further study of downward surface solar net radiation in future.     

非化学处理对储粮病虫害的控制进展

在粮食储藏中广泛使用的化学药剂已受到严格限制，各种无毒无害且环保的非化学处理对储粮病虫害的控制成为近年来研究的热点之一。本文探讨了目前国内外研究开发的代替化学手段的生物、物理方法以及如何结合安全的储藏条件控制储藏中的病虫害。     

水果保鲜技术及其保鲜机理的研究进展

综述了水果物理、化学和生物保鲜技术及保鲜机理的研究进展,分析了不同保鲜技术方法的利弊,展望了建立适合我国国情的水果保鲜技术与安全质量监控体系的前景。     

Research in Automation Process Planning About Sheet Metal

Along with the development and appliance of the artificial intelligence, professional have adopted many kinds of methods such as expert system, NN and so on to explore an innovation type CAPP. The paper gives a brief introduction to the principle and design methods of process planning based on the theory of expert system developing a computer aided process planning system of sheet metal and discusses in detail the system uses the network graph to describe the parts and technology decision-making route, and the methods of separated reasoning and various expressions of knowledge are used to solve the complexity of development in CAPP research. Finally satisfied the requirement of the practicability?opening and intelligence about the system.     

棉花转基因技术的研究及应用

目前应用于棉花遗传转化的主要转基因技术是农杆菌介导、基因枪和花粉管通道导入外源基因等方法。本研究对这3种方法的技术特点、研究动态及其在棉花分子育种中的应用进行了综述。     

An Unsteady Flow Analysis in Gas Transmission Pipeline Based on Theory of Functional Analysis

Branch -like pipeline is a common structure in gas transmission pipeline. In the light of the constituent properties of natural gas branch - like pipeline system, the system can be divided into fundamental constituent units. This paper presents a realistic unsteady flow model consisting of simple models of pipeline units and connecting conditions, boundary conditions and initial condition associated with units by using system analysis method. The solutions in wide sense are obtained by theory of functional analysis and operator series method, Such a method has the properties of both analytical solution and numerical solution methods. When the divided pipeline unit is larger, an intuitive approximate analytical solution may be obtained; while the one is smaller, a more accurate numerical solution may be acquired. Based on this, a general computer program has been developed for this model and solutions have been used successfully in a local natural gas transmission network in Sichuan. It is proved that the model and algorithm proposed in this paper are of the advantages of convenient calculation, high precision, time saving and wide application range by way of analysis and application.     

微孔保鲜膜制备方法与应用

全面介绍微孔保鲜膜的不同制备方法、微孔保鲜膜的主要性能特点及其应用前景,并简要分析微孔保鲜膜今后的发展方向.     

葫芦科植物的遗传转化研究进展

葫芦科植物中包括多种以采收果实为主的蔬菜作物，对其进行品质改良、延迟成熟和抗病虫害的遗传转化研究具有重要的理论和实践意义。目前，在葫芦科植物中已建立了子叶、茎尖、胚轴、茎段、原生质体和子叶节等的再生体系；用于遗传转化的方法有农杆菌介导法、基因枪法、花粉管通道法、DNA浸泡法等；用于转化的目的基因多为抗病毒病基因和延迟成熟的基因；NPTII基因为最常用的筛选标记基因。主要对以上几个方面进行综述，并讨论了葫芦科植物遗传转化过程中的影响因素及存在的问题。     

日韩梨贮藏保鲜技术研究与应用进展

从品种选择、采收期、贮藏温度、贮藏气体条件4个方面阐述了影响日韩梨贮藏保鲜质量的若干因素,对土窑洞贮藏、冷库贮藏、CA贮藏和MA贮藏方法与应用进行了总结,并且讨论了日韩梨的贮藏保鲜研究方向。