D36580/97t锥顶储罐罐顶桁架的整体吊装和旋转就位

本文针对大型储罐罐顶整体桁架结构尺寸大、质量大、易变形的特点,详细介绍了一种切实可行的整体吊装及旋转就位方法。从选定吊装方案入手,阐叙了实现本方法的思路和技术细节,提出了实施过程中的注意事项。实践证明,该方法能保证安装质量,安全、可靠、可行。     

利用CFD获取超声流量计截面速度分布

 通过CFD技术在超声波流量计设计过程中的引入,为流量系数的获取提供了新的途径.通过对特定管道的理论计算表明,采用CFD技术获取的管道内部流型完全可以与试验数据吻合,有助于超声波流量计应用场合流量系数曲线的获取及其精度的保证.     

Overview of ship-design expert systems

Expert systems constitute a branch of artificial intelligence, and their unique characteristics enable computer systems to perform at the level of a human expert by the use of algorithms that can capture domain-specific knowledge. Through an extensive survey of research about ship-design expert systems, we conclude that although development and implementation of expert systems for ship design offer substantial barriers, the shipbuilding industry needs them nonetheless. We examine the major reasons that use of expert systems in this industry has lagged behind. These include the problems of integration with existing computer-aided design systems, problems of knowledge representation and sizable development costs. We discuss in detail some key factors that can lead to the solution of these problems.     

一个可切实服务于运营商的移动无线因特网

本文在简单介绍了移动IP及其路由优化，无线局域网（WLAN）和GPRS的基础上，提出了一个新的利用移动IP来融合WLAN和GPRS的移动无线因特网的网络结构，详细论述了其多连接的路由过程，平滑垂直切换，AAA，并做了简要的性能分析。     

基于POSC的测井曲线数据存储管理系统

在基于POSC标准的基础上，分析了POSC EPICENTER数据模型，对油田中普遍使用的LS716测井大块数据在磁盘和远程自动磁带库之间实现了一体化的数据管理，开发了数据加载，数据删除，头信息浏览线回施行能模块。该系统特点是，管理信息加载到POSC数据仓中，而真正的数据体以外部数据文件的形式存放，使得大块数据的加载和提取速度大大提高，同时，在数据仓库和远程带库之间实现了一体化的数据管理。     

NO emission characteristics in counterflow diffusion flame of blended fuel of H2/CO2/Ar

Flame structure and NO emission characteristics in counterflow diffusion flame of blended fuel of H₂/CO₂/Ar have been numerically simulated with detailed chemistry. The combination of H₂, CO₂ and Ar as fuel is selected to clearly display the contribution of hydrocarbon products to flame structure and NO emission characteristics due to the breakdown of CO₂. A radiative heat loss term is involved to correctly describe the flame dynamics especially at low strain rates. The detailed chemistry adopts the reaction mechanism of GRI 2.11, which consists of 49 species and 279 elementary reactions. All mechanisms including thermal, NO₂, N₂O and Fenimore are taken into account to separately evaluate the effects of CO₂ addition on NO emission characteristics. The increase of added CO₂ quantity causes flame temperature to fall since at high strain rates a diluent effect is prevailing and at low strain rates the breakdown of CO₂ produces relatively populous hydrocarbon products and thus the existence of hydrocarbon products inhibits chain branching. It is also found that the contribution of NO production by N₂O and NO₂ mechanisms are negligible and that thermal mechanism is concentrated on only the reaction zone. As strain rate and CO₂ quantity increase, NO production is remarkably augmented. Copyright © 2002 John Wiley & Sons, Ltd.     

The onset of vortex instability in laminar forced convection flow through a horizontal porous channel

The onset of convective instability in a fluid-saturated porous layer between the two horizontal plates heated isothermally from below has been analyzed theoretically by using propagation theory. In the analysis the thermal dispersion coefficient is assumed to be proportional to the streamwise velocity. The results show that both inertia and thermal dispersion stabilize the system.     

重金属(以铅计)含量测定方法的改进

探讨了用硫化钠-丙三醇溶液代替饱和硫化氢水溶液进行重金属(以铅计)测定的分析方法。此法简单、快速,并在实际应用中取得了满意的结果。     

电算法在液压支架受力分析中的应用

建立支架受力分析的电算设计数学模型并给出程序框图     

Accumulation of thiobarbituric acid‐reactive substances in cured pork sausages treated with propolis extracts

Propolis collected by bees has many components that possess antifungal, anticancer and antioxidant properties. Cured ground pork meat was treated separately with 0.4% w/w ethanol‐extracted propolis (EEP 0.4%), 0.6% w/w water‐extracted propolis (WEP 0.6%), 0.8% w/w dried residue of ethanol‐extracted propolis (DREEP 0.8%) and 0.1% w/w potassium sorbate (PS 0.1%) and made into sausages. Thiobarbituric acid‐reactive substances (TBARS) were measured in the sausages to assess the effects of storage at 5, 10 and 20 °C after 0, 2 and 4 weeks. After 4 weeks of storage at 5 °C the sausages treated with EEP 0.4%, DREEP 0.8%, WEP 0.6% and PS 0.1% yielded TBARS values which were 50, 59, 35 and 91% respectively of the control value. There was an increase of 0.33 mg MDA kg^?1, the lowest of all treatments, in TBARS for the 0.4% w/w EEP‐treated sausages. The curing process will control microbiological spoilage, as will potassium sorbate. © 2002 Society of Chemical Industry