加热器内部泄漏故障的实验研究

高压加热器内部泄漏故障是火电厂回热系统主要故障之一,针对加热器的泄漏故障进行实验研究,设计并搭建高加泄漏模拟实验台.通过实验研究和数据处理,找出不同工况下泄漏声发射信号的最大能量值、最大频率值以及平均频率3个参数在发生泄漏故障时的变化规律.以期准确提供泄漏相关参数的特征,这将有利于故障的早期诊断和排除.     

带高压一级旁路的1000MW汽轮机不设高排逆止门的布置改进

论述了采用高压缸启动方式的带高压一级旁路的1000MW超超临界汽轮机不设高排逆止门的依据及其防止汽轮机甩负荷超速、高缸超温与进水的方法:一是在高压导汽管上加装通风阀,二是在冷再管上加装通往凝汽器的排汽管,三是在冷再管的低位加装能显示水位、自动报警及自动疏水的疏水罐。这种设计布置是带有高排逆止门原设计的改进。根据改进结果,可以得出具有防止汽机甩负荷超速、防止空转时汽机高压部件过热、防止汽机进水的完善功能,达到系统简单、安全适用、减少投资目的的结论。     

基于矩阵分解的周期块三对角线性方程组的并行直接解法

提出了分布式环境下求解周期块三对角线性方程组的一种并行算法．该算法充分利用系数矩阵结构的特殊性,通过对系数矩阵进行适当分解及近似处理,使算法只在相邻处理机间通信2次,并从理论上给出了算法有效的一个充分条件．最后,在HP rx2600集群上进行了数值试验,结果表明,实算与理论是一致的,并行性也很好．     

Combined effect of high pressure treatment and anti-microbial bio-sourced materials on microorganisms' growth in model food during storage

Antimicrobial bio-sourced films based on poly(lactic acid) containing either carvacrol or allyl isothiocyanate (AITC) were prepared and their antimicrobial properties were assessed on Botrytis cinerea during storage and after a high pressure (HP) “pasteurisation-like” treatment (up to 800 MPa at ambient temperature). A dry process (extrusion + thermomoulding) was used to shape the material. The high temperature encountered during film processing dramatically decreased the carvacrol and AITC content in the film, leading to a less efficient antimicrobial activity. The use of β-cyclodextrin (β-CD) to encapsulate the active compounds before film processing proved to be efficient to protect the AITC against thermal degradation and to control its release from the films during its use. PLA-based films containing either AITC or β-CD encapsulated AITC showed a significant activity against B. cinerea. An effective combination between the antimicrobial activity of AITC-based films and the high pressure treatment was observed on a model food system (PDA) inoculated with N × 10⁴ (N ~ 1–9) conidia of B. cinerea. An HP treatment of only 300 MPa associated with an antimicrobial PLA/β-CD system providing an initial quantity of active agents equivalent to 4 mg of AITC/L of air (i.e. almost 2 folds lower than the minimal inhibition concentration of the active packaging used alone, which was determined to be equal to 10 mg/L of air in the same conditions) was found more efficient (total inhibition of B. cinerea growth during 10 days) than an 800 MPa HP treatment used alone (increase of the lag phase growth of 3.3 days).

Industrial relevance

The consumer demand for “fresh like” product containing reduced amount of preservatives without compromising human and environmental safety needs the development of new preservation strategies. As a consequence, the concept of “hurdle technologies” has risen up. The combined effect of HP treatment and volatile antimicrobial packaging allowed the use of lower individual treatment intensities to inhibit B. cinerea growth. Combining such “hurdles” is of relevance in the context of development of low-cost and eco-friendly food technologies.     

基于Web3D技术的工程施工可视化仿真应用研究

为了直观地表述水利水电工程施工过程和施工形象，并对来自工程施工的信息进行管理和分析处理．以提高水电工程施工过程信息化管理与决策水平，结合长江三峡工程二期厂坝施工的实践，应用VRML虚拟现实建模语言及PHP动态网页技术，实现了基于网络三维技术(Web3D)的水电工程施工过程可视化仿真和施工信息的交互式查询，为施工管理决策者提供了远程科学决策的信息支持．     

航天反射镜材料SiC

航天反射镜材料的一些优选性质包括密度低、弹性模量高、热膨胀系数低及热传导率高。与传统光学材料相比,碳化硅(SiC)具有优异的机械和热性能,被认为是引入注目的反射镜材料。本文概述了SiC的基体成形工艺和机械精加工工艺,讨论了其优缺点,并概述了国内外的发展现状。     

引进型汽轮发电机组甩负荷工况特点及改进

为解决某电厂机组在甩负荷时出现的高压缸排汽温度升高甚至达到跳闸值的问题，从控制原理人手，分析了机组甩负荷时可能出现的转速控制方式以及由此产生的对高压缸排汽温度的影响特点，指出高压缸排汽温度升高是由于OPC动作后高压调节门未及时打开所致。确定了甩负荷时控制策略的改进方案：在再热蒸汽压力一定的情况下，适当限制中压调节门开度，及时打开高压调节门。经实际甩负荷试验表明，改进后的控制方案不但有利于甩负荷时的转速稳定，而且使高压缸排汽温度升高问题得到显著改善，解决了由于机组甩负荷引起的高压缸排汽温度超标等问题。     

基于HP VEE语言的数字示波器模块开发应用

HP VEE作为一种可视化的编程语言 ,在仪器控制方面有许多独特的优点。它具有软面板和直接输入输出两种方式 ,可用来对仪器进行控制操作。就其结合 HP E142 6 A型数字示波器模块的开发应用 ,阐述了分别利用上述两种方式控制 HP E142 6 A型数字示波器模块的一般步骤以及在具体测试中所采用的方法和应注意的要点 ,并且还对测试过程中出现的问题作了描述和解释     

Study of anti-coking property of SiO2/S composite coatings deposited by atmospheric pressure chemical vapor deposition

To alleviate catalytic coking on the inner surfaces of radiant tubes for ethylene production in petrochemical plants, SiO₂/S composite coatings were prepared on the surface of HP40 steel tube using dimethyldisulfide (DMDS) and tetraethylorthosilicate (TEOS) by atmospheric pressure chemical vapor deposition. A comparison of anti-coking property of the coated and uncoated HP40 steel tubes has been made under the same conditions. SiO₂/S composite coatings are compact and have better anti-coking property. The coke on the coated HP40 steel tube is about 22% of that on the uncoated HP40 steel tube, and only small granular coke is deposited on the coated HP40 steel tube. However, the filamentous coke is formed on the uncoated HP40 steel tube. SiO₂/S composite coatings have good thermal stability at cracking temperature by the comparison of Raman spectra before and after coking.     

高温高压超深井中途测试工艺的改进及应用

摘要根据胜利油田高温高压井测试的特点，分析了测试工作的重点、难点，提出了一系列技术改进措施。用HST工具取代MFE测试工具、VR安全接头取代P-T封隔器，在测试管柱、测试压差、测试制度等方面进行优化创新。经现场实际应用，测试成功率和施工质量明显提高。