根霉脂肪酶有机相合成己酸乙酯条件的研究

用根霉ZM-10脂肪酶为催化剂,在有机相中催化合成己酸乙酯。文中研究了温度、底物浓度、酸醇比、溶剂、吸水方法等对己酸乙酯合成转化率的影响。结果表明,以环己烷为溶剂,以摩尔比为1∶1.3的己酸和乙醇为底物,己酸浓度为0.2 mol/L,在40℃条件下振荡反应14h,合成己酸乙酯的的转化率可达到91.5%。     

以受众思维和媒介观念强化创作——基于接受之维的交互艺术创作研究

互动媒体驱动艺术的创作内容、艺术形式发生变革,由此引发新的观众接受方式。交互艺术的观众接受现象表现出不同于传统审美的特点,本文基于此对交互艺术创作相关问题进行研究,分析交互艺术的受众接受现象及接受视野等问题,阐释交互艺术的文本召唤结构与受众从观望走向参与的接受路径,阐明受众思维和媒介观念在相关设计实践中的重要价值。     

流媒体技术及其应用

流媒体是网络环境中的一种新的媒体形式,本文探讨了流媒体技术,并对其主要应用做了介绍。     

Numerical simulation of density-driven natural convection in porous media with application for CO2 injection projects

In this paper we investigate the mass transfer of CO₂ injected into a homogenous (sub)-surface porous formation saturated with a liquid. In almost all cases of practical interest CO₂ is present on top of the liquid. Therefore, we perform our analysis to a porous medium that is impermeable from sides and that is exposed to CO₂ at the top. For this configuration density-driven natural convection enhances the mass transfer rate of CO₂ into the initially stagnant liquid. The analysis is done numerically using mass and momentum conservation laws and diffusion of CO₂ into the liquid. The effects of aspect ratio and the Rayleigh number, which is dependent on the characteristics of the porous medium and fluid properties, are studied. This configuration leads to an unstable flow process. Numerical computations do not show natural convection effects for homogeneous initial conditions. Therefore a sinusoidal perturbation is added for the initial top boundary condition. It is found that the mass transfer increases and concentration front moves faster with increasing Rayleigh number. The results of this paper have implications in enhanced oil recovery and CO₂ sequestration in aquifers.     

流式音频及RealSystem系统

概括阐述了以边下载边播放的形式在网上传输多媒体信息的新技术-流式媒体技术，并着重介绍三大解决方案中目前较具优势的方案-RealSystem系统。     

Rapid vaporization of subcooled liquid in a capillary structure

A novel process is introduced for rapid vaporization of subcooled liquid in a capillary structure. The process consists of a low-thermal-conductivity porous wick, heated from a downward-facing grooved heating block that is in intimate contact with the upper surface of the wick structure. For such a specially configured heat transfer device, measurements show that vapor can be generated rather quickly once a sufficient amount of heat was applied. The mechanisms leading to the rapid vaporization of liquid are numerically investigated. It is found that the low thermal conductivity of the capillary structure and the presence of the extremely steep temperature gradients at the fin/porous structure interface due to the rather weak natural convection, reflected by small-scale secondary flow cells below the heated fins, are responsible for the rapid vaporization of subcooled liquid.     

Antibacterial Effect of Glucose Oxidase on Growth of Pseudomonas fragi as Related to pH

The effect of glucose oxidase (GOX) catalyzed reaction with glucose on Pseudomonas fragi was analyzed in nutrient broth and fish extract media. Growth of P. fiugi in nutrient broth was clearly suppressed by 1.0, 2.0 and 4.0 mg/mL glucose when combined with 0.5–2.0 U/mL GOX. The same GOX/glucose combinations inhibited P. frasi growth in fish extract media. Viable cell numbers in fish media showed clear growth inhibition with combinations of l.0–2.0 U/mL GOX and 8.0–16.0 mg/mL glucose. Higher GOX and glucose rapidly produced 2.0–2.5 unit decreases in pH, but produced enough gluconic acid to precipitate fish proteins. Use of 0.5 U/mL GOX in fish extract media resulted in slow, sustained activity with potential for inhibition of microbial growth in foods without excessive acidity.     

等径棒球介质在煤磨中的应用

对比等径棒球介质与传统圆球介质在煤磨中使用情况,等径棒球研磨介质在增产、节能和提高粉体 制备质量等方面具有显著的技术经济效果,其具有广阔的推广应用前景。     

气藏多孔介质中组分吸附等温线的建立

根据吸附位势（位能）理论，利用Dubinin吸附势的定义，对于同一种类型的吠附剂（多孔介质），对不同吸附质在不同温度条件下测得的吸附实验数据，将其吸附量和吸附势相关联，拟合得到相应的回归方程。并利用拟合得到的回归方程，针对某个气藏（Case2)，在确定的平均气层岩心参数的条件下，建立该气藏在给定气层温度下所有组分的吸附等温线。此项研究工作将为开展多孔介质中吸附作用的各种研究（如吸附平衡相态模拟和油气藏数值模拟研究等）提供重要的基础数据和研究方法。     

Minimum Depth of Soil Cover above Soil–Steel Bridges

Soil–steel bridges are built of flexible corrugated steel panels buried in well-compacted granular soil. Their design is based on the composite interaction between the soil pressures and the displacements of the conduit wall. The structure failure could be initiated by shear or tension failure in the soil cover above the steel conduit. The provisions for design given in different codes, such as the Canadian Highway Bridge Design Code, managed to avoid some of the problems associated with the failure of soil above soil–steel bridges by requiring a minimum depth of soil cover over the crown of the conduit taking into consideration the geometric shape of the conduit. However, the present code requirements for a minimum depth of cover were developed for a maximum span of 7.62 m and using nonstiffened panels of 51 mm depth of corrugation. The effect of having larger spans or using more rigid corrugated panels has not been examined before and is the subject of this paper. The present study uses the finite-element analysis to re-examine the possible soil failures due to centric live loads (i.e., loads acting symmetrically about the mid span of conduit) or eccentric live loads. The study deals with spans up to 15.24 m of circular conduits and 21.3 m of arches with deep corrugations. It has been found that, in addition to the conduit geometry, the actual dimension of the span should be considered to determine the required depth of soil cover.