功能梯度材料组元设计的研究进展

综述目前功能梯度材料的国内外研究情况,从双组元和多组元设计角度着重阐述目前研究进展。展望今后功能梯度材料组元设计的发展方向。     

零部件制造商加工制造能力考核评价方法的研究

在全球经济一体化的环境下,复杂产品的制造是由多个制造商共同完成。为考核不同制造商零部件的加工能力,需要对制造商的加工能力进行分析。在简单叙述多色集合和多色图的基础上,运用多色集合理论及多色图,建立了产品加工系统的数学模型,然后根据多色集合的析取和合取形式,对制造商的加工能力给出了分析预测的数学公式和方法。用案例说明了应用上述理论的步骤和方法。     

夹绳器专用电磁铁的设计

通过对一种电梯上行超速保护装置广泛采用的夹绳器的简单分析．引出了安全部件所用的电磁铁的性能要求．详细分析了直流电磁铁的时间特性．给出了优化直流电磁铁时间特性的几种方法。     

Environmental labelling of timber-framed dwellings and their building components

Demands by customers for environmentally better products produced under economically sound conditions are increasing steadily. Wood has a lower environmental impact than most of the competing materials used in the building sector. However, for reliable customer information, environmental impact verification methods for timber-frame houses are needed. The Forest Stewardship Council (FSC) is a forest certification scheme operating at a global level. It relies upon a performancebased standard that includes specific performance measures that can be used as a basis for product labelling; minimizing the environmental impact is covered by one of the FSC's ten principles. A case study of a customized timber-frame house illustrates the possibility of using the FSC percentage-based volume criteria as an environmental labelling, ensuring criteria that the wood products come from well-managed forests. The case study demonstrates not only the simplicity, but also the drawbacks of applying the FSC labelling to complex wood products such as houses, and an analysis of a proposed model gives insights into how the FSC labelling can be extended for houses by incorporating building functional and service-life criteria.

Les consommateurs demandent de plus en plus de produits qui soient meilleurs pour l'environnement et qui sont fabriqués dans de bonnes conditions économiques. L'impact du bois sur l'environnement est plus faible que celui de la plupart des matériaux qui le concurrencent et qui sont utilisés dans le secteur de la construction. Toutefois, pour que les informations fournies aux consommateurs soient fiables, il faut avoir recours à des méthodes de vérification de l'impact des maisons à charpente en bois sur l'environnement. Le FSC (Forest Stewardship Council) est un organisme d'homologation forestier présent dans le monde entier. Il s'appuie sur une norme basée sur les performances qui inclut des mesures de performances spécifiques pouvant servir de base à l'étiquetage des produits ; la réduction de l'impact sur l'environnement est couverte par l'un des dix principes du FSC. Une étude de cas portant sur une maison à charpente en bois « sur mesure » illustre les possibilités d'utilisation des critères de volume du FSC (pourcentages) en tant qu'étiquette environnementale, ces critères garantissant que les produits du bois proviennent de forêts bien gérées. Cette étude de cas fait non seulement la preuve de la simplicité mais expose aussi les inconvénients de l'application de l'étiquetage FSC à des produits en bois complexes tels que les maisons; l'analyse d'un modèle proposé donne des éléments informatifs sur la possibilité d'étendre l'étiquetage FSC à des maisons en incorporant des critères fonctionnels et de service.     

Method for determining novolac glycidyl ether (NOGE) and its chlorohydrins in oily canned foods

In order to be analysed, NOGE components with epoxy groups must be separated from polar food material to prevent losses through uncontrolled reactions. Samples are homogenized minimally and extracted into a phase of minimized polarity. The NOGE components are then separated from the oil by extraction into acetonitrile and analysed by RPLC with fluorescence detection. Hydrolysis of the epoxy and chlorohydroxy functions to diols may help the analysis. Application and limitations of the method are illustrated by examples. Detection limits vary widely, depending on interfering food components, but legal limits below 1mg/kg can hardly be reliably enforced.     

Is it possible to predict gas yields of any biomass after rapid pyrolysis at high temperature from its composition in cellulose, hemicellulose and lignin?

Ligno-cellulosic biomass from different sources presents very variable compositions. Consequently, there is a wide variation in the nature and quantities of gaseous products obtained after thermal treatment of biomasses.The objective of this work is to establish a link between the composition of a biomass and its pyrolysis gas yields and composition. Experimental flash pyrolysis of several biomasses at a temperature of 950 °C and a gas residence time of about 2 s was carried out. An attempt was then made to predict gas yields of any biomass according to its composition. We show that an additivity law does not allow the gas yields of a biomass to be correlated with its fractions of cellulose, hemicellulose and lignin. Several potential explanations are then offered and quantitatively demonstrated: it is shown that interactions occur between compounds and that mineral matter influences the pyrolysis process.     

Office办公组件间的数据转换

通过调用相应的命令。进行合理的设置．能在多个办公组件之间进行一些数据的相互转换。形成资源共享。     

Frequency domain methods applied to forecasting electricity markets

The changes taking place in electricity markets during the last two decades have produced an increased interest in the problem of forecasting, either load demand or prices. Many forecasting methodologies are available in the literature nowadays with mixed conclusions about which method is most convenient. This paper focuses on the modeling of electricity market time series sampled hourly in order to produce short-term (1 to 24 h ahead) forecasts. The main features of the system are that (i) models are of an Unobserved Component class that allow for signal extraction of trend, diurnal, weekly and irregular components; (ii) its application is automatic, in the sense that there is no need for human intervention via any sort of identification stage; (iii) the models are estimated in the frequency domain; and (iv) the robustness of the method makes possible its direct use on both load demand and price time series. The approach is thoroughly tested on the PJM interconnection market and the results improve on classical ARIMA models.     

不同树龄白果中营养成分的比较分析

利用不同方法对不同树龄的银杏树所产的白果中的水分、脂肪、淀粉和多糖等主要营养成分进行了比较分析。结果表明,100年树龄的银杏树所产白果的营养成分含量较高,而800年树龄的银杏树所产白果和邳州市产白果的营养成分含量较少。其结论可为白果的深加工提供一定的依据。