棉花对淹水胁迫的适应机制

淹涝是造成棉花减产的重要灾害因素。在淹水胁迫下,棉花的生长发育会受到不利影响,中、重度持续淹水还会引起棉花减产甚至绝产。但是,棉株自身具有完整的适应保护机制,遭受淹水胁迫后通过启动逃避机制、静止适应机制和再生调节补偿机制,适应淹水胁迫、减少涝害损失。本文重点就棉花对淹水胁迫的3个适应机制进行了详细论述,就淹水胁迫对棉花生长发育、生理特性和产量性状的影响以及缓解棉花淹水伤害的主要措施与方法也作了简要评述。     

基于AHP方法的黑龙江粮食主产县发展策略研究

为了寻求黑龙江省粮食主产县的发展策略,促进黑龙江省区域经济运行质量的全面提升,运用美国运筹学家Saaty的多目标决策层次分析法(Analytical Hierarchy Process,AHP),依据黑龙江省10个粮食主产县发展现状,构建了黑龙江省粮食主产县层次分析模型。通过分析黑龙江省产粮大县普遍存在的粮食优势与经济劣势的关系,找出粮食主产县县域经济发展落后、经济结构不合理、后续产业发展滞后等问题,在构建的层次分析模型中将需要解决的问题分解成发展战略、制约因子及解决措施等层次和元素,运用德尔菲法确定了粮食主产县在发展中应从构建粮食主产县利益补偿机制入手,力争突破土地制约并拓展域外农业,同时应积极发展粮食主产县第二、三产业,并继续巩固提高农业基础设施建设,从而提升黑龙江省粮食主产县的自身积累和发展能力。     

中国绿豆种质资源初选核心种质构建

以国家作物种质资源数据库中5 072份国内绿豆资源为材料, 根据14个农艺性状, 利用地理来源(省)和性状群进行分组, 分别采用比例法、平方根法和多样性指数法确定取样数及聚类选择和随机选择2种个体选择法构建了13个不同的绿豆初选核心样本, 对不同的取样方法及总资源间进行了品种间平均相似性系数、性状符合度、遗传多样性指数和数量性状变异系数的比较。结果表明, 聚类选择取样优于随机取样, 按照性状群分组优于按省分组; 在聚类选择条件下采用多样性指数法确定取样数优于平方根法和比例法。最终确定按性状群分组, 利用多样性指数确定取样数, 聚类选择个体为绿豆核心种质构建的最佳方案。用此方案, 构建了包含719份绿豆种质的初选核心种质, 取样比例为14.2%, 性状符合度达100%。     

Study and Simulation on Control Strategy for CVT Ratio in HEV when Regenerative Braking

In order to satisfy the safety of vehicle braking and the fuel economy,a control strategy for regenerative braking force distribution is proposed by considering of battery SOC and braking severity.In addition,a CVT speed ratio control strategy is proposed to operate the motor in the high efficiency area to improve motor generating efficiency.A simulation model of mild hybrid electric vehicle is set up.Simulation result on ECE+EUDC typical driving cycles show that the effectively regenerating energy of braking of hybrid vehicle with CVT is lager than that of hybrid vehicle with MT by 2.5%.     

Overall control strategy and operational performances of a doubly fed wind turbine generator system

In order to comprehensively and correctly analyze the real-time operational characteristics of a grid-connected wind turbine generator system, it is necessary to analyze the overall control strategies and operation performances of the wind turbine generator system. According to the type of a doubly fed wind turbine generator system, the mathematical models of wind turbine, drive train and doubly fed induction generator (DFIG) are presented. From the viewpoints of the maximum wind energy capture and safe operation of the wind turbine, a maximum power output control strategy is proposed by considering the DFIG loss minimization, and a variable pitch control strategy is also presented by considering generator rotational speed restriction and the output power restriction. Combined with a power decoupling strategy of DFIG, the overall operational performances of the doubly fed wind turbine generator system are simulated. By comparing the simulation, theoretical analysis and actual operational data, the results show that the presented model and overall control strategies of the doubly fed wind turbine generator system are valid.     

Control Strategy for Asychronized Turbogenerators

Asynchronized Generator can better solve the excessive reactive and stability problem in power system.In order to improve the dynamic and transient performances of an asynchronized turbogenerator(ASTG),excitation control equation of it in the dynamic synchronous reference frame is presented.Control results are simulated in the synchronous and dynamic synchronous reference frames for ASTG.It is shown that the dynamic and transient performances in the dynamic synchronous reference frame are better than those in the synchronous reference frame.Consequently,the control strategy of dynamic synchronous reference frame can shorten more time on the dynamic process of ASTG.     

中国热带作物产业发展的战略思考

为科学、高效和可持续发展热带作物产业提供参考依据,主要分析中国热带作物产业发展概况,并与世界热带作物产业进行比较,进而探讨热带作物产业发展的思路、目标,提出发展热带作物产业的3个路径选择：（1）国内适度规模发展,做精做强,建立和完善现代热带作物产业体系;（2）实施“引进来”战略,着力提高热带作物产业的综合生产能力;（3）实施“走出去”战略,合作开发境外热带作物资源,积极开辟国际贸易市场。     

基于多项Logit模型的牧户生计资本对生计策略选择影响的实证研究

为探究牧户生计资本对生计策略影响,识别牧户生计策略转化的关键生计资本和生计资本指标,以便引导牧民调整生计结构,提高草原治理能力。以内蒙古自治区5种草原类型15个旗（县）848户牧户为样本,运用熵值法评估牧户生计资本,建立多项Logit回归模型,识别影响牧户生计策略转化的关键生计资本。研究区牧户生计资本值为1.428;4类生计策略牧户生计资本存量为纯牧性>牧兼性>兼牧性>非牧性,P< 0.01;5种草原类型牧户生计资本存量为草甸草原>典型草原>荒漠草原>沙地草原>草原化荒漠,P<0.01。牧户以牧业收入和政府转移收入为主,纯牧性生计策略为首选的策略;金融资本存量是影响生计策略转化的关键生计资本,对牧户由纯牧性向牧兼性、兼牧性和非牧性生计策略转化均具有显著负向影响。牧户家庭承包草地资源、使用草地资源和家庭总收入是影响生计策略转化的关键生计资本指标。     

Analysing the Changing Landscape of European Financial Centres: The Role of Financial Products and the Case of Amsterdam

ABSTRACT The turn of the twenty‐first century saw the re‐emergence of debates about the reconfiguration of European financial geographies and the role of stock exchange mergers in this process. There has been, however, no systematic attempt to date to analyse such changes. This paper proposes a specific conceptual framework to explore these issues. It uses a product‐based analysis to examine, in the context of recent stock exchange mergers, the factors affecting the competitiveness of a financial centre. It argues that it is important to understand three intertwined influences—product complementarities, the nature of local epistemic communities, and regulation—and their contingent effects on change. This is exemplified by a tentative application of the framework to the case of Amsterdam in order to better understand its recent decline in competitiveness as a European financial centre.     

浅论4Cs营销理论在农业信息服务中的应用

随着中国对“三农”问题的日趋重视以及社会主义新农村建设战略的出台,农业、农村、农民问题成为中国政府当前及今后工作的重中之重。“三农”问题的根本解决取决于多方面因素,大力提高农业信息服务的水平和效率无疑对于“三农”问题的最终解决有巨大的助力作用。为了推动中国农业信息服务的发展,切实提高农业信息服务的水平和效率,笔者运用比较分析的方法对中国农业信息服务进行营销创新的可能和重要性进行了深刻剖析,从营销学的角度探讨了中国农业信息服务理念、方式的创新,最后提出了农业信息服务的营销对策。     

Police-based encryption for privacy protection of trust negotiation

Privacy protection technologies of automated trust negotiation have witnessed great development, among which hidden credentials is an admittedly more satisfactory one. However, for hidden credentials, there exists fatal weakness of blindly decryption, which results decryption execution costly. To solve the problem, using bilinear pairings over elliptic curves, a policy-based encryption for privacy protection is proposed. Under the assumption of BDH problem, the scheme is proven to be IND-Pol-CCA safety in the random prediction model. Compared with hidden credentials and other encryption solutions based on policy, this scheme is more efficient, secure and of shorter length of cipher text.     

氮肥运筹对小麦群体变化、穗粒数分布及产量的影响

为小麦持续增产提供重要技术途径,对氮肥不同施用量和不同底追比例进行研究,选用‘周麦18’作为试验材料,研究了氮肥运筹技术对小麦群体动态变化、穗粒数分布及产量的影响。结果表明：“前轻中重后补充”的氮肥运筹技术降低了小麦生育期的最高群体,小麦分蘖成穗率较传统施肥处理提高了3.1个百分点,同时增加了穗粒重、提高了千粒重,单穗重显著提高了0.2 g;在每公顷施纯氮240 kg和180 kg条件下,运用“前轻中重后补充”氮肥运筹技术较传统施肥处理（全底）增产694.5 kg/hm2、486.0 kg/hm2,增幅分别为10.1%和7.2%。结果说明“前轻中重后补充”的氮肥应用策略是一项高产高效的氮肥运筹技术。     

重金属污染对土壤动物的影响

随着工业污染的加剧和农用化学物质的增加,土壤中的重金属污染日益严重,其中一部分重金属残留物被土壤动物吸收和富集后,通过食物链对动物和人类健康造成了很大的威胁。该文在讨论重金属富集特性的基础上,从个体、种群及群落水平上综合分析了重金属污染对土壤动物的毒害作用,并论述了土壤动物对重金属污染的解毒策略,最后从重金属污染的毒性测定方法、复合污染机制、分子机理研究和土壤动物的生态恢复作用等几个方面,阐述了当前研究主要动态和今后的发展趋势,旨在为今后的研究提供参考依据。     

基因克隆策略在抗稻瘟病基因分离中的应用

稻瘟病是限制水稻生产的主要病害之一,不断分离克隆抗性基因并通过现代生物技术培育抗病水稻新品种是防治该病最经济有效的途径。介绍了当前4种主要的基因克隆即转座子标签法、图位克隆法、电子克隆法和电子图位克隆法的原理和操作流程,并概述了已克隆的19个稻瘟病抗性基因的克隆途径,分别举例介绍了抗稻瘟病基因图位克隆策略、电子图位克隆策略和转座子标签法克隆策略的主要流程。结合研究实践,提出稻瘟病基因的克隆要在不断通过对抗病基因结构和功能深入了解的基础上,灵活选择不同基因分离策略,发挥多种克隆策略的长处。     

Selection Theory and Method of Stock Investment Strategy

The author analyzes and concludes the factors that affect the stock market, and gives out the theory basis of the model and its feasibility; Then, based on the related knowledge of statistics and unit exchange, the selection theory and its corresponding model of stock investment strategy are gotten to describe the risk situation of stock market. At last, the author concludes the selection method of stock investment strategy and does the empirical study to prove that the strategy is both right and efficient.     

农业生态区昆虫群落特点与害虫生态控制策略

文章系统阐述了农业生态区昆虫群落特点与影响因素,探讨了农田害虫生态控制策略。旨在优化农业害虫生态控制策略,实现农业害虫的自控或半自控防治,促进新型生态农业的发展。     

中国热带农业科技国际合作发展策略研究

概述了中国热带农业科技的对外合作现状,指出中国热带农业科技国际合作已经拥有了一定的基础;同时,分析了中国热带农业科技国际合作存在的问题。在上述研究基础上,提出了以下发展策略以进一步促进中国热带农业科技国际合作：国家应有计划、有步骤地组织国内热区农业科技力量开展国际合作,针对不同国家农业资源及其科技发展特点,采取不同的合作对策;参与或组织实施国际科技合作项目和重大国际合作计划,充分利用国际智力,争取引领国际热带农业科技发展。     

创新农业科技发展战略，加快推进农业科技进步

系统总结了农业科技取得的成就,科学分析了农业发展所面临的挑战,提出了农业科技进步是农业发展的决定力量,农业发展的根本途径在于农业科技进步,同时围绕农业科技创新提出了实施农业科技创新战略、农业科技产业化战略、农业科技体制创新战略、创新条件与平台提升战略,以进一步提升农业科技的支撑能力、引领能力,不断增强农业的抗风险能力、国际竞争能力和可持续发展能力。     

Application of Improved Hierarchic Genetic Algorithm to Damage Detection of the Main Girder for Cable-stayed Bridge

In the process of damage identification for high-order nonlinear structure such as cable-stayed bridges by the standard genetic algorithm, premature convergence would appear. In order to avoid this, an improved hierarchic genetic algorithm was proposed. The cable force change was used to establish the optimization function and threetypes of standard genetic algorithm were combined with variable fine-tuning and hierarchic strategy.To establish a hierarchical genetic algorithm with catastrophe characteristics A single-tower cable-stayed bridge model was used in the numerical simulation and the result showed that the probability of premature convergence was reduced in the improved hierarchic genetic algorithm and and the cable-stayed bridge damage was identified effectively. The anti-noise performance was better.     

Game Analysis between Manufacturer and Wholesaler in the Management of Distribution Channel

In the distribution channel management, a good cooperation relationship between manufacture and wholesaler is an effective way for them to complement each other with their respective advantages, improve channel competitive abilities and adapt to market fluctuations. Based on their mutual cooperative relationship, a mixed game model is constituted by introducing the characteristics and postulating the prerequisites of trade between manufacturer and wholesaler, then the factors affecting their mutual cooperative relationship and the conditions of their stable cooperation are found through analyzing the mixed game model. Furthermore, a finitely repeated game model is used to analyze the cooperation between manufacturer and wholesaler, the conclusion of the cooperative qualification that influences the cooperation of both sides is given. As a result, the strategies employed by the manufacturer and wholesaler are pointed out.