网络环境下国际商务实验教学研究

为了解决我国大学生“供求悖论”的问题,该文应用教育理论中的建构主义原理,就网络环境下国际商务实验教学模式进行了分析,得出在教学改革中要从培养目标开始就要重视培养学生的实际应用能力,并提出了相应的对策和思路．参3．     

沃特世超高效合相色谱系统首次亮相中国

沃特世（Waters）公司在慕尼黑上海分析生化展（analytica China）推出最新技术的Waters ACQUITY UPC2TM系统,它是分离科学仪器的一个新类别.利用超高效合相色谱（UPC2）的工作原理,沃特世ACQUITY UPC2系统作为正交分离技术的补充用于解决复杂的色谱问题,尤其适用于处理极性各异的样品．任何使用液相色谱或气相色谱的实验室,将因在其分析技术中增加合相色谱而受益．     

可持续发展对采矿部门的挑战

支撑实际上所有可持续能力定义的基本原理现在已经应用于采矿部门，然而，它们的应用仍然具有明显和潜在的障碍 障碍包括原理本身以及它们在一些情况下与当前运作的社会和经济系统不一致这一事实．我们作出如下结论：由于有许多途径来定义和实施可持续发展，引用它的原理可能带来不同的可能结果．这井不降低解决公开问题的可能性，而且它更可能为适合每一种特定矿物操作或活动的特殊条件的平衡的解决方法，以及每一个国家的独特处境带来机遇．     

多媒体课件在病理生理学教学中的应用

病理生理学是一门医学基础学科,是沟通基础医学与临床医学的桥梁,理论性和逻辑性强,知识点多,既有局部微观的病理机制,又有宏观的整合原理．在病理生理学教学中,应用多媒体课件教学,可以增强学生学习的兴趣,活跃课堂气氛;增加了教学信息量;使抽象、复杂的基本概念、原理形象化、简单化等优点,同时也要避免多媒体技术对病理生理学教学的一些误区,必须正确认识并发挥它的优势,与传统的教学模式进行互补,从而提高教学质量．参6．     

控制思想在《自动控制原理》教学中的实践

本文将闭环控制原理运用于自动控制理论的教学实践，阐述了怎样保证“教”和“学”的各环节协调作用．并对自动控制理论课程的教学改革后的教学思想、教学方式、教学手段进行了探索和实践，并取得了良好的效果．     

城市污水深度处理工艺的设计与运行

在水资源日趋紧张的今天,污水的深度处理回用工艺成了人们探讨的热点。结合郑州市五龙口污水处理厂的设计与运行,介绍了以改良氧化沟为主体的污水深度处理回用工艺,并对工艺除磷脱氮及污水深度处理的原理、设计参数、运行情况及运行条件的控制进行了介绍。运行结果表明该工艺既具有较高的COD、SS去除效率,又解决了传统氧化沟在脱氮除磷时存在相互影响的矛盾问题,在进水COD为326mg/L、SS为301mg/L、NH_4~+-N为45．1mg/L、TP为4．1mg/L;出水COD为21mg/L、SS为9mg/L、NH_4~+-N为1．4mg/L、TP为0．6mg/L,各项指标均达到了景观用水标准。     

生态设计——一种有希望的可持续生产与消费思路

生态设计——一种有希望的可持续生产与消费思路在过去１５年中,联合国环境署为帮助工业界改善其环境表现已经做了很多工作．注意力起初集中在工业过程中,然后,又转移到环境管理系统上．然后,到了解决工业生产的最根本方面的时候：产品本身．在１９９０年代初,启动和...     

可持续消费与清洁生产:同一个事情的两个方面

“寿命周期经济”是可持续生产和消费政策的一个综合性手段．这一范围内的工作意味着解决一个事情的两个方面(即可持续消费和清洁生产)以确保实施最有效的手段和战略国家清洁生产中心在这个领域具有重要的作用．     

农业生态经济系统生态效益综合评价方法探讨

根据系统思想和生态学原理，探讨了农业生态经济系统的生态效益和功能的定量评价方法，并给出了相应的计算规则．同时还阐述了这一方法在广西壮族自治区来宾县的实际应用。     

环境经济学的发展与创新

资源短缺、环境恶化，是人类社会发展所面临的突出问题，为解决这些问题，我国制定了保护资源、维护生态平衡的基本国策．而如何实施这些国策，并解决好有实施过程中出现的问题，还有待于理论上的指导，这个理论便是关于资源环境与经济发展过程中的内在联系的理论．因此，创建环境经济学，显得非常紧迫．     

Observations on the biology of Donax trunculus and D. vittatus at Ile d'Oléron (French Atlantic coast)

Observations have been made on the biology of two species of the bivalve genus Donax, on two beaches, Vertbois and St. Trojan, on the Ile d'Oléron, French Atlantic coast. The two species displayed different vertical distribution: D. trunculus Linné in the intertidal; and D. vittatus (da Costa) between low-water spring tide (LWST) and 5 to 6m depth, with only the fringe of the population extending to the shore. D. trunculus also showed differential distribution by size or age, the youngest individuals being highest on the shore, and the oldest near LWST. The two species exhibited a similar pattern of seasonal recruitment and growth, but in both there were differences in growth characteristics between the two beaches, individuals at St. Trojan growing to a larger size than those at Vertbois. The mean pattern of mortality in the two areas was similar, and productivity per 100 recruits surviving to the first winter following settlement was greater at St. Trojan than at Vertbois. For D. trunculus the mean population density at Vertbois was higher and the production per unit area on the two beaches was similar. Production to biomass (B) and elimination to biomass (B) ratios were similar for the two beaches for both species, and while production was greater for D. trunculus at both beaches, the B and B ratios were higher for D. vittatus. Comparisons with other published data reveal that the rate of growth of D. trunculus is similar throughout its range from Brittany to the Mediterranean Sea, while that of D. vittatus shows more variation. In both species, there is a trend of increasing P/B and E/B ratios from north to south throughout the geographical range.     

Review and comparison of methods to study the contribution of variables in artificial neural network models

Convinced by the predictive quality of artificial neural network (ANN) models in ecology, we have turned our interests to their explanatory capacities. Seven methods which can give the relative contribution and/or the contribution profile of the input factors were compared: (i) the ‘PaD’ (for Partial Derivatives) method consists in a calculation of the partial derivatives of the output according to the input variables; (ii) the ‘Weights’ method is a computation using the connection weights; (iii) the ‘Perturb’ method corresponds to a perturbation of the input variables; (iv) the ‘Profile’ method is a successive variation of one input variable while the others are kept constant at a fixed value; (v) the ‘classical stepwise’ method is an observation of the change in the error value when an adding (forward) or an elimination (backward) step of the input variables is operated; (vi) ‘Improved stepwise a’ uses the same principle as the classical stepwise, but the elimination of the input occurs when the network is trained, the connection weights corresponding to the input variable studied is also eliminated; (vii) ‘Improved stepwise b’ involves the network being trained and fixed step by step, one input variable at its mean value to note the consequences on the error. The data tested in this study concerns the prediction of the density of brown trout spawning redds using habitat characteristics. The PaD method was found to be the most useful as it gave the most complete results, followed by the Profile method that gave the contribution profile of the input variables. The Perturb method allowed a good classification of the input parameters as well as the Weights method that has been simplified but these two methods lack stability. Next came the two improved stepwise methods (a and b) that both gave exactly the same result but the contributions were not sufficiently expressed. Finally, the classical stepwise methods gave the poorest results.     

我国丹顶鹤自然保护区网络设计

针对原有丹顶鹤保护区规划缺乏系统设计思想,保护区面临严重的生境安全这一问题,根据维持生态系统地域完整性和生态过程完整性的原则,采用迭代法和整数规划2种方法,以高、中适宜性湿地面积占各自湿地类型总面积70%和60%为保护目标,研究了丹顶鹤自然保护区的网络设计,提出了丹顶鹤自然保护区网络的设计方案。     

Sulfate-enhanced degradation of Rhodamine B in the hydrogen peroxide/hydroxylamine system

Environmental Chemistry Letters - Hydroxyl radicals are commonly produced either by metal activation or by using external energy. However, the application of these methods is limited by low working...     

水安全智能识别模型的建立及应用

通过人口迁移算法优化投影寻踪模型,提出了一种新的水安全智能识别模型。与遗传算法优化的投影模型相对比,人口迁移算法的自身优势有效地避免了网络早熟现象及寻找全局最优解的困扰。从水安全的评价结果来看,用人口迁移算法优化投影寻踪是可行的,并显示出优越性。人口迁移算法为求解投影寻踪模型的非线性约束提供了新的优化方法,并为水安全评价工作提供了新的智能识别模型。     

白光散斑法原理及其发展

白光散斑法——一种较新的用于力学实验分析的方法,从其发展历程出发,简述其在40多年里的发展历史和其目前在中国国内的发展研究现状,并就其基本原理,位移信息提取的两种方法即逐点分析法和全场分析法,做了简要叙述.简单的介绍了白光散斑法的实际测量过程,并简要总结其自身独特的优势、适用的领域和其今后大体发展的趋势.图1,参27.     

广东省耕地分等中的土壤肥力评价指标体系

土壤肥力评价是耕地分等的基础及重要组成部分。土壤肥力评价的关键是评价指标体系的确定，指标的选择原则主要有主导性原则、稳定性原则、差异性原则、分层次控制原则、定量分析与定性分析相结合原则。指标分值和权重的确定方法主要是模糊评价法和层次分析法，但必须依据土壤学的研究成果和生产实践经验。     

Das OECD-Prüfrichtlinienprogramm

The Test Guideline of the OECD (organisation for Economic Co-operation and Development) is concerned with the international harmonisation of physicochemical, ecotoxicological and toxicological testing methods for chemicals and pesticides. New guidelines have been actualised and survey reports (Detailed Review Papers — DRP) dealing with test methods and the related questions have been compiled for the OECD member countries. The basic work to this international programme has occurred by way of the national co-ordinators who represent the interface between the national experts and the OECD bodies. The co-ordination of the Test Guidelines in Germany involves specific experts as well as the routine convention of working groups for exchanging the specific state of affairs and the respective strategies employed.     

Predicting community responses to perturbations in the face of imperfect knowledge and network complexity

How best to predict the effects of perturbations to ecological communities has been a long-standing goal for both applied and basic ecology. This quest has recently been revived by new empirical data, new analysis methods, and increased computing speed, with the promise that ecologically important insights may be obtainable from a limited knowledge of community interactions. We use empirically based and simulated networks of varying size and connectance to assess two limitations to predicting perturbation responses in multispecies communities: (1) the inaccuracy by which species interaction strengths are empirically quantified and (2) the indeterminacy of species responses due to indirect effects associated with network size and structure. We find that even modest levels of species richness and connectance (-25 pairwise interactions) impose high requirements for interaction strength estimates because system indeterminacy rapidly overwhelms predictive insights. Nevertheless, even poorly estimated interaction strengths provide greater average predictive certainty than an approach that uses only the sign of each interaction. Our simulations provide guidance in dealing with the trade-offs involved in maximizing the utility of network approaches for predicting dynamics in multispecies communities.     

土壤养分空间估测方法研究综述

土壤养分是土壤提供的植物生长发育所必需的营养元素。由于受到自然因素和人为因素的共同作用,土壤养分具有高度的空间变异性。土壤的这种特性不仅表现在区域尺度上,而且也表现在田块尺度上。在研究方法上经历了从传统统计学到地统计学,再到神经网络、地理信息技术以及高精度曲面建模等新方法的不断改进过程。文章从地统计学方法引入到土壤养分空间变异研究中为出发点,论述了国内外基于地统计学的土壤养分空间变异的研究现状,主要包括利用地统计学方法来确定合理的土壤采样数目,土壤养分空间变异的定量化研究,土壤养分空间变异的尺度效应;然后简述了神经网络、地理信息技术、高精度曲面建模等技术在土壤养分空间变异研究中的研究现状和应用。最后对比分析了各种研究方法在应用中存在的缺陷,同时指明了今后应加强作物生长的不同时期土壤养分的空间变异性、土壤在四维空间尺度上的演变机理以及环境信息获取的不确定性等方面的研究。