拉格朗日－达朗伯方程的普遍意义及不便求解的问题

拉格朗日－达朗伯方程是动力学普遍而统一的方程，是分析力学的基础，本文阐述了方程的普遍意义；指出了应用时的限定条件；用它推导建立了动力学３个普遍定理和机械能守恒定律；并探讨了方程的局限性和不便求解的问题。     

Systems biology: a brief overview

To understand biology at the system level, we must examine the structure and dynamics of cellular and organismal function, rather than the characteristics of isolated parts of a cell or organism. Properties of systems, such as robustness, emerge as central issues, and understanding these properties may have an impact on the future of medicine. However, many breakthroughs in experimental devices, advanced software, and analytical methods are required before the achievements of systems biology can live up to their much-touted potential.     

处理黑色体系的几种化学计量学算法的比较

对近期提出的几种处理黑色分析体系的二维数据的算法－－渐进因子分析法，迭代目标转换因子分析法，演进因子分析法，直观推导式渐进因子分析法等４种算法进行比较研究，为了方便比较，以光谱或色谱的协方差阵的行列式作为体系重叠度的度量，在此基础上，对确定未知混合物组分数和纯组分光谱及色谱的分辨结果进行了较详细的讨论，ＨＥＬＰ给出最佳结果。     

In situ formation of an oxygen-evolving catalyst in neutral water containing phosphate and Co2+

The utilization of solar energy on a large scale requires its storage. In natural photosynthesis, energy from sunlight is used to rearrange the bonds of water to oxygen and hydrogen equivalents. The realization of artificial systems that perform "water splitting" requires catalysts that produce oxygen from water without the need for excessive driving potentials. Here we report such a catalyst that forms upon the oxidative polarization of an inert indium tin oxide electrode in phosphate-buffered water containing cobalt (II) ions. A variety of analytical techniques indicates the presence of phosphate in an approximate 1:2 ratio with cobalt in this material. The pH dependence of the catalytic activity also implicates the hydrogen phosphate ion as the proton acceptor in the oxygen-producing reaction. This catalyst not only forms in situ from earth-abundant materials but also operates in neutral water under ambient conditions.     

Managing natural resources: A social learning perspective

This article presents a social learning perspective as a means to analyze and facilitate collective decision making and action in managed resource systems such as platforms. First, the social learning perspective is developed in terms of a normative and analytical framework. The normative framework entails three value principles, namely, systems thinking, experimentation, and communicative rationality. The analytical framework is built up around the following questions: who learns, what is learned, why it is learned, and how. Next, this perspective is used to analyze two managed resource systems: Fishery management in Lake Aheme, Benin and water resources management in Gelderland, The Netherlands. To assess platform performance in resource use negotiation, emerging lessons from the case studies are combined with propositions concerning membership of platforms, accessibility of platform meetings, skills and relations of platform members, realization of platforms, and third party facilitation of platform activities.     

具有参数激励约简的扰动KdV方程的混沌行为

研究了具有参数激励约简的扰动KdV方程的混沌动力学行为.利用改进的Melnikov方法分析了由于同宿轨道的横截相交而产生的混沌行为.对周期外激励、周期线性参数激励和周期非线性参数激励下的扰动KdV方程的混沌行为进行了比较,发现划分混沌区与非混沌区的临界曲线是互不相同的.尤其是对非线性参数激励系统,存在"死频率".当这类系统受到该频率激励时,不论激励的振幅多大,混沌也不会发生.用时间积分法对上述系统进行了数值计算,结果与理论分析一致.     

Equilibrium regained: from nonequilibrium chaos to statistical mechanics

Far-from-equilibrium, spatially extended chaotic systems have generally eluded analytical solution, leading researchers to consider theories based on a statistical rather than a detailed knowledge of the microscopic length scales. Building on the recent discovery of a separation of length scales between macroscopic behavior and microscopic chaos, a simple far-from-equilibrium spatially extended chaotic system has been studied computationally at intermediate, coarse-grained scales. Equilibrium properties such as Gibbs distributions and detailed balance are recovered at these scales, which suggests that the macroscopic behavior of some far-from-equilibrium systems might be understood in terms of equilibrium statistical mechanics.     

PMU最优配置及其在舰船电力系统中应用研究

针对舰船电力系统的特点和在潮流方程求解中存在的问题，借鉴在陆地电力系统中配置相应的PMU将使潮流方程直接可解的思想，实现采用遗传和粒子群优化算法的基于潮流可解最优PMU配置方案算法。并对其在舰船电力系统中的有效性和适用性进行了比较，可为舰船电力系统配置PMU提供参考。     

基于CGE模型的政策模拟系统的研究

针对目前政策模拟分析系统缺乏的问题,提出利用计算机技术将CGE模型、DSS、数据仓库、数据转换等集成在一个模拟系统中:采用Visual C .net开发模拟分析系统的人机交互界面和问题处理系统;GAMS IDE完成CGE模型生成和求解系统;数据仓库采用SQL Server 2000设计并实现,构造了政策模拟原型系统。在所设计的模拟系统上,以农业补贴政策模拟为例,通过情景分析法进行实证模拟分析。结果表明:模拟集成系统初步实现了CGE建模、模拟计算、系统维护及人机交互的功能。该模拟系统能够解决实际政策模拟问题,辅助决策者进行政策制定。     

基于小波变换的拉曼光谱去噪处理

拉曼光谱分析中,噪声的存在严重影响光谱的准确性。利用小波变换在信号处理方面的优良特性,采用基于小波变换的信号去噪方法,对含噪的邻二甲苯拉曼光谱进行处理。选用平稳小波 bior2.2处理了含噪的邻二甲苯拉曼光谱信号。结果表明,采用平稳小波 bior2.2可以将信噪比由10dB 提升到21.3588dB,而均方误差仅为0.0014,去噪效果明显。     

基于小波变换的拉曼光谱去噪处理

拉曼光谱分析中,噪声的存在严重影响光谱的准确性。利用小波变换在信号处理方面的优良特性,采用基于小波变换的信号去噪方法,对含噪的邻二甲苯拉曼光谱进行处理。选用平稳小波bior2·2处理了含噪的邻二甲苯拉曼光谱信号。结果表明,采用平稳小波bior2·2可以将信噪比由10dB提升到21·3588dB,而均方误差仅为0·0014,去噪效果明显。     

Phototaxis and sensory transduction in Euglena

The accumulation of Euglena gracilis in an illuminated region is brought about by two main mechanisms: orientation and subsequent directed movement (positive phototaxis) toward light scattered from particles in the illuminated zone; and by the trapping of cells in this region because of shock reactions experienced upon the cells encountering a sudden decrease of light intensity at the light-dark boundary (inverse photophobic responses).Phototactic orientation is mediated by inverse photophobic reactions which occur when the shadow of the stigma periodically falls upon the photoreceptor proper. Euglena also exhibits shock reactions when an already high light intensity is increased further (direct photophobic responses). The expression of both types of phobic responses depends upon stimulus intensity and adaptation of the sensory system in a seemingly complex way. A definition of the minimum components of the stimulus transduction system and a systems analytical approach to the study of input-output relationships enables one to construct an electronic analog of the cell's signal processing system that converts the photoreceptor input to commands which activate or inhibit flagellar reorientation. Computer simulation studies show that this model has considerable predictive value. It is hoped that with the approach presented in this article, a generalized model has become available for dealing with the questions of sensory transduction in aneural systems. Certainly, at this point more questions have been raised than have been answered. Where is the processing device located? Are its kinetic properties determined by electrical processes or by the rates of chemical reactions? Is the processor, and thereby the behavior of the orgamism, modulated by natural environmental parameters, and can it be modified permanently through more drastic chemical treatment of the cell? Is the system capable of permanent or transitory modification through repeated response, that is, does it exhibit phenomena analogous to learning and memory in higher organisms? These are only a few of the problems that require study in the future.     

联用二维数据黑色体系的多组份解析与直观推导式渐进特征投影法

本文首先对黑色分析体系化学计量学解析方法的发展历史作了简要回顾，为对现存各方法的适应性进行了评价，着重讨论了联用色谱二维数据的重要特性，在此基础上，对直观推导式渐进特征投影法的主要思路进行了较详尽剖析，列出几种不同的，现仍不能为已有方法有效解析之体素，以期引起化学计量学家们的注意。     

食品废水培养枯草芽孢杆菌产絮凝剂及固定化吸附Cu~（2＋）研究

[目的]利用食品废水培养枯草芽孢杆菌（Bacillus subtilis）AS1-296产絮凝剂吸附Cu2＋。[方法]以味精废水和啤酒废水作为替代培养基培养枯草芽孢杆菌AS1-296制备含γ-聚谷氨酸的絮凝剂,通过正交试验确定其最佳培养条件,对枯草芽孢杆菌产的絮凝剂进行了明胶-戊二醛交联固定处理,并对Cu2＋进行吸附和解析研究。[结果]培养枯草芽孢杆菌AS1-296产絮凝剂的最佳条件为：pH为7,培养时间为48 h,啤酒废水与味精废水的体积比为15。红外光谱分析结果显示,絮凝剂主要由γ-聚谷氨酸和多糖组成。固定后的絮凝剂最佳Cu2＋吸附条件为：最佳吸附pH为5,絮凝剂投加量为0.6 g,温度为40℃,Cu2＋初始浓度为30 mg/200 ml,最大Cu2＋吸附容量为4.1 mg/g。最佳Cu2＋解析条件为：pH为2,最大解析率为81%。[结论]利用味精废水和啤酒废水作为主要原料,使培养枯草芽孢杆菌AS1-296产絮凝剂更具有经济和实用价值,真正实现了＂以废治污＂。 更多还原     

Stretchable and foldable silicon integrated circuits

We have developed a simple approach to high-performance, stretchable, and foldable integrated circuits. The systems integrate inorganic electronic materials, including aligned arrays of nanoribbons of single crystalline silicon, with ultrathin plastic and elastomeric substrates. The designs combine multilayer neutral mechanical plane layouts and "wavy" structural configurations in silicon complementary logic gates, ring oscillators, and differential amplifiers. We performed three-dimensional analytical and computational modeling of the mechanics and the electronic behaviors of these integrated circuits. Collectively, the results represent routes to devices, such as personal health monitors and other biomedical devices, that require extreme mechanical deformations during installation/use and electronic properties approaching those of conventional systems built on brittle semiconductor wafers.     

Synteny and collinearity in plant genomes

Correlated gene arrangements among taxa provide a valuable framework for inference of shared ancestry of genes and for the utilization of findings from model organisms to study less-well-understood systems. In angiosperms, comparisons of gene arrangements are complicated by recurring polyploidy and extensive genome rearrangement. New genome sequences and improved analytical approaches are clarifying angiosperm evolution and revealing patterns of differential gene loss after genome duplication and differential gene retention associated with evolution of some morphological complexity. Because of variability in DNA substitution rates among taxa and genes, deviation from collinearity might be a more reliable phylogenetic character.     

Expert systems in forestry: Utilizing information and expertise for decision making

Expert systems are computer programs designed to simulate the problem-solving ability of human experts in specialized fields. They incorporate a knowledge base that contains the scientific knowledge and experience for solving specific types of problems, a data base for the facts pertinent to particular problems, and a control program that constructs lines of reasoning to solve the problems. They have been successfully applied in many fields, but very few forestry applications have been reported.The authors have developed an expert system, named PREDICT, to help foresters diagnose pest problems in red pine (Pinus resinosa, Ait.) stands, based on symptoms easily observed in the field. The program recognizes 28 different causes of symptoms in red pine, and incorporates over 400 inference rules in its knowledge base. The manner in which expert systems solve problems is illustrated with an example from the pest diagnosis system. Preliminary experience with the pest diagnosis application suggests that expert systems can be very effective at solving forestry problems of this type. Other areas of forestry that might benefit from the application of expert systems include silviculture, site evaluation, reforestation, and inventory design. The authors encourage other forestry researchers to investigate possible applications of expert systems. Several topics are discussed that are of importance to anyone considering the application of expert systems to areas of forestry.Tools for developing expert systems are readily available, and they can be implemented on desk-top computers for easy access by professionals in all sectors of forestry. Expert systems provide a framework for presenting the latest scientific knowledge and decision-making expertise in a form that can be readily applied by foresters in the field.     

Decision support system for nitrogen fertilization using fuzzy theory

During the last three decades there has been great concern about the impact of agriculture on the environment and its resources. Conventional agriculture is based on whole field and mostly empirical approaches to defining and applying agrochemical inputs, which poses certain limitations regarding the management of existing variability in agricultural land. In this paper, the design and application of a fuzzy decision support system, concerning site specific nitrogen fertilization, is described. The system uses an easy but efficient way of solving the nitrogen equation under agricultural conditions and is based on knowledge elicitation and fuzzy logic methodologies. More specifically, the system is composed of two parts; a knowledge base and an analytical modular part which simulates nitrogen balance. The analytical part is built in a four level structure which consists of eleven fuzzy systems. The evaluation of the system presupposes the availability of 14 state variables that can be easily collected and refer to characteristics of the soil, weather and farming practices. The incorporated knowledge and the formulation of fuzzy rules were based on interviews with experts and on annotating scientific and technical bibliographic resources. A sensitivity analysis of the developed system was carried out in order to evaluate its robustness against errors or uncertainty in the state variables and further to assess and highlight the important variables. The application of the system using a set of point data, drawn from cotton fields in central Greece and stored in a Geographical Information System, is described in brief and the results show considerable variability in the recommended amount of nitrogen fertilizer among the reference sites.     

麦类作物不同品种混合群体的生产性能评述

同种作物不同品种混作由于表现出比单作在产量及其稳定性、抗病性、品质等方面的优势而受到广泛关注,在国内外已做了大量研究,其中尤以对麦类作物研究较多。回顾了麦类作物不同品种混作的研究成果,评述了麦类作物不同品种混合群体的生产性能,并对产生各种效应的机理进行了总结,最后对麦类作物混作的应用和需要进一步研究的问题提出了建议。     

非线性渗流区域井流问题渗流速度的分区研究

为了精确求解两种流态并存区域上井流问题的渗流速度,在非线性渗流区域内对渗流规律中的非线性指数进行了分区研究,通过对水均衡方程用Boltzmann变换进行求解,推导出了线性与非线性渗流区域内渗流速度的解析表达式。