注化学剂驱油数值模拟(理论部分)

本文给出了一个多维多相多组分注化学剂(如表面活性剂、醇、聚合物)驱油的数学模型。该模型考虑了化学驱替过程中各种主要的质量转换过程(对流、扩散、液相间质量转换及液固相间转换)及足以适应现场应用的各种边界条件。它可以模拟各种几何形状多孔介质中的多相渗流问题,每一相都可能是一个多组份的混合物。在目前的物化知识条件下,该模型考虑了尽可能多的物化现象及参数影响,模型中毛细数在时间和空间上的分布影响,合宜的相平衡处理,活性剂损失及来自实验的其它物化资料的处理等,使得它有别于其它模型,这使它更能正确地描述现实问题。它可被用来模拟解释实验室试验结果,进行机理性研究,优选注入化学剂段塞组份和尺寸等,也可用于模拟现场条件下注化学剂驱油过程。预测驱油特性及各参数的影响,解决各种实际问题。     

A principled approach to developing legal knowledge systems

In this article we present a principled, four-phased approach to the development of legal knowledge systems. We set out from the well-studied CommonKADS method for the development of knowledge systems and tailor this method to the legal domain. In particular, we propose a generic legal ontology, and describe the creation of statute-specific ontologies to adopt the method for building legal systems. In the construction of these ontologies, we start from a theoretical analysis of the legal domain. The well-known example of the Imperial College Library Regulations (ICLR) is used to illustrate the method.     

基于C/S的县(市)级土地利用总体规划管理信息系统的设计与开发——以江阴市为例

县（市）级土地利用总体规划是有限的土地资源科学管理、合理利用的前提,而县（市）级土地利用总体规划管理信息系统是规划动态实施和实时管理的科学保障。以江阴市为研究区,分析、设计、开发了以Ｃｌｉｅｎｔ／ｓｅｒｖｅｒ为体系结构的土地利用总体规划管理信息系统     

Confocal microscopy and spectroscopy of InGaN epilayers on sapphire

We report a preliminary investigation of spatial inhomogeneities in an InGaN epilayer using scanning confocal microscopy as the investigative tool. The Daresbury confocal microscope SYCLOPS provides simultaneous high quality reflection and fluorescence images of InGaN sample areas up to 500 μm square, even at room temperature. Sample cooling increases the brightness and quality of the fluorescence image, as expected. Spectral selection using interference filters permits identification of features close to sample edges resulting from the nitridation of indium droplets. The unexpected non-coincidence of fluorescence and reflection features below 10 μm in size is tentatively attributed to the differing absorption strengths of different crystallites.     

A THIRD-ORDER NUMERICAL SCHEME WITH UPWIND WEIGHTING FOR SOLVING THE SOLUTE TRANSPORT EQUATION

Solute transport in the subsurface is generally described quantitatively with the convection–dispersion transport equation. Accurate numerical solutions of this equation are important to ensure physically realistic predictions of contaminant transport in a variety of applications. An accurate third-order in time numerical approximation of the solute transport equation was derived. The approach leads to corrections for both the dispersion coefficient and the convective velocity when used in numerical solutions of the transport equation. The developed algorithm is an extension of previous work to solute transport conditions involving transient variably saturated fluid flow and non-linear adsorption. The third-order algorithm is shown to yield very accurately solutions near sharp concentration fronts, thereby showing its ability to eliminate numerical dispersion. However, the scheme does suffer from numerical oscillations. The oscillations could be avoided by employing upwind weighting techniques in the numerical scheme. Solutions obtained with the proposed method were free of numerical oscillations and exhibited negligible numerical dispersion. Results for several examples, including those involving highly non-linear sorption and infiltration into initially dry soils, were found to be very accurate when compared to other solutions. © 1997 by John Wiley & Sons, Ltd.     

Polygon Inflation for Animated Models: a Method for the Extrusion of Arbitrary Polygon Meshes

A method for the extrusion of arbitrary polygon meshes is introduced. This method can be applied to model a large class of complex 3-D closed surfaces. It consists of defining a (typically small) set of connected polygons in 3-D that form a skeleton of the final object, and assigning extrusion distances to all polygons. The two sides of a polygon may have different extrusion distances. An automatic extrusion algorithm constructs a closed 3-D polygon mesh around the skeleton, making use of the indicated extrusion distances. We call this process inflating the polygons of the skeleton. Unlike traditional extrusion, the method works for non-planar skeleton configurations, and it also supports branching skeleton structures (i.e. edges with more than two incident polygons). © 1997 by John Wiley & Sons, Ltd.     

BERRY SEEDS: A SOURCE OF SPECIALTY OILS WITH HIGH CONTENT OF BIOACTIVES AND NUTRITIONAL VALUE

Selected berry seed oils from blackberry, blueberry, cranberry, strawberry, red raspberry and kiwi were characterized for their quality and nutritional characteristics. These oils are by-products of berry juice production that have only recently gained commercial interest. Free fatty acid content was below 1.6% for all examined oil samples. Peroxide value ranged between 0.6 and 44 mg O₂/kg oil for blackberry and kiwi seed oils, respectively, and p -anisidine value varied from 6 in cranberry to 23 in strawberry. Linolenic acid content ranged from 17.53% in blackberry seed oil to 57.60% in kiwi seed oil. The oxidative stability of all oils was rather low (0.17 h for kiwi to 8.4 h for blackberry at 97.8C). Phytosterol contents ranged between 403 and 692 mg/100 g for blackberry and cranberry, respectively. The content of tocols (tocopherol  +  tocotrienol) varied from 34.4 for kiwi to 2,133 mg/kg for red raspberry seed oils.

PRACTICAL APPLICATIONS

A waste stream of fruit processing is used to extract the oil from berry seeds. Such oils are particularly rich in essential fatty acids (with a favorable low n-6/n-3 ratio) and antioxidants. They are incorporated in cosmetic preparations such as hand and body creams, and shampoos. Their composition is also interesting from a nutritional point of view. As the commercial interest is growing, chemical studies are necessary to elucidate the composition, activity and stability of different berry seed oils.     

Probiotic buttermilk-like fermented milk product development in a semiindustrial scale: Physicochemical, microbiological and sensory acceptability

Probiotic buttermilk-like fermented milk in different flavors in versions with sucrose and sucralose were processed in a pilot plant. The Mesophilic Aromatic Culture CHN-22 and Bifidobacterium animalis Bb12 were the cultures employed for fermentation. Physicochemical composition, apparent viscosity, diacetyl content, viability of cultures during storage, and acceptance of product via sensorial analysis were assessment factors. The high viability of the probiotic culture was observed (average 8.08 log cfu/ml) during refrigerated storage (28 days) of buttermilk and good acceptance of the product via sensory test. However, the probiotic culture might have been responsible for the loss of diacetyl, a volatile compound that is a characteristic feature of the product.     

铸铁中碳测定方法的改进

碳是铸铁中最重要的元素。因此,在铸造过程中需要经常对碳进行监控。取样过程非常关键,冷凝速度过慢就会产生石墨夹杂。然而,火花直读光谱仪进行测定时需要完全不含石墨的样品才能得到精确的测量结果。本文对这种要求的原因进行了研究和讨论,并对一种测定碳新方法的原理和可行性进行了阐述。该方法改进了测定未达到最佳标准要求的铸铁样品中碳含量的准确性,并能提示取样过程是否恰当。     

Helical Baffles in Shell-and-Tube Heat Exchangers,Part I: Experimental Verification

Performance of heat exchangers with helical baffles, or helixchangers, is discussed using the results of tests conducted on units with uarious baffle geometries. An optimum helix angle is identified at which the conversion efficiency for converting pressure drop to heat transfer on the shell side of helixchangers is maximized. Designs for standard industry applications are optimized using the analysis of test results.