37 resultados para 183-1136


Relevância:

10.00% 10.00%

Publicador:

Resumo:

A new aerodynamic principle of flame stabilization and combustion intensification, the coflow jets with large velocity difference, is described. One or more small high-velocity jets of air or steam, injected off the axis and in the same direction as the low-velocity main fuel-air flow into the combustor, create a large recirculation zone of high turbulence intensity in which the combustibles and high temperature gases are effectively mixed, so that stable and intensive combustion can be maintained even for fuels with poor ignition. A pulverized coal combustor based on the principle mentioned above is shown to be characteristic of excellent combustoom and a simple structure. A number of precombustors of this type are in operation at some power stations and industrial boilers of China. Using such precombustor, successtul startups and part-load operation of the boilers have become available under conditions of unpreheated air and low-grade coal with volatiles as low as 15% and ash content as high as 30%. This principle shows good promise as an attractive new technology of combustion.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

导弹潜射是集高速流动、冲击、结构响应于一体的流体—固体—气体三态非线性耦合复杂过程,是决定潜射导弹发射成败的关键环节。本文应用LS-DYNA显式程序建立了三种包含水体、空气、导弹、发射井和筒盖的多物质耦合ALE网格模型,使用罚函数流体—固体耦合方法对导弹水下无攻角潜射过程进行了数值模拟,给出了弹体质心的轴向加速度、轴向流体阻力及阻力系数、空泡区压力分布。仿真结果表明,模型2的仿真过程与实际导弹潜射过程最为相符。同时总结介绍了LS-DYNA程序中流体—固体耦合计算的相关设定原则和方法。本文可为潜射导弹的水动力载荷设计和数值仿真提供有益的参考。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

对爆轰驱动段的发展进程进行了回顾.比较了反向与前向爆轰驱动段的优缺点.提出在前向爆轰驱动段上游增加反向辅爆轰驱动段,来消除主驱动段中爆轰波后的Taylor波,改善其驱动性能.这种双爆轰驱动段只要辅与主驱动段初始压力比等于或大于临界值,主驱动段中的Taylor波将不再出现,可产生均匀的高温高压驱动气体.此外,还能产生过驱动爆轰波,进一步提高驱动能力.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

目录

Relevância:

10.00% 10.00%

Publicador:

Resumo:

目录

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The Tie-2 receptor has been shown to play a role in angiogenesis in atherosclerosis. The conventional method assaying the level of soluble Tie-2 (sTie-2) was ELISA. However, this method has some disadvantages. The aims of this research are to establish a more simple detection method, the optical protein-chip based on imaging ellipsomtry (OPC-IE) applying to Tie-2 assay. The sTie-2 biosensor surface on silicon wafer was prepared first, and then serum levels of sTie-2 in 38 patients with AMI were measured on admission (day 1), day 2, day 3 and day 7 after onset of chest pain and 41 healthy controls by ELISA and OPC-IE in parallel. Median level of sTie-2 increased significantly in the AMI patients when compared with the controls. Statistics showed there was a significant correlation in sTie-2 results between the two methods (r=0.923, P0.01). The result of this study showed that the level of sTie-2 increased in AMI, and OPC-IE assay was a fast, reliable, and convenient technique to measure sTie-2 in serum.