Comparison of Displacement and Mixing Diffusers

In order to cumpare the peformance of different supply diffuers of ventilation air, the airflow passern, temperature stratifiation and contaminant dispersion in a furnitured office ventilated by three kinds of air diffuer were numerically investigated. The air diffuers studied in this paper are a quarter-cylinder displacement diffuer on the floor and mixing diffuers (linear and vortex diffuers) on the ceiling. The heat sources in the of-fice are considered to be 50% convective and 50% radiative. The k-? two-equatwn model of turbulence is employed to predict the turbulent diffusion. The results show that the displacement diffuser provides a rather uniform flow field with low velocify in most areas, and the vertical temperature difference from floor to ceiling is as high as 6 K. With the linear diffuser, the air velociry is high, and the temperature is uniform both horizontally and vertically. The air velocity generated by the vortex diffuser is moderate. The distributions of the temperature and the contaminant are rather uniform.     

企业施工定额的编制以及施工成本分析平台的应用

本文阐述了施工企业内部编制定额的必要性和成本分析平台的实用性,并根据多年的工作经验就建筑施工企业对施工成本的控制谈谈一自己的认识和看法.     

低旋流进气直喷燃烧系统在195柴油机上的应用研究

介绍了低旋流进气直喷燃烧系统应用于１９５柴油机的试验结果，着重探讨了燃烧室结构尺寸和供油系统主要参数对柴油机性能和燃烧放热规律的影响。研究表明，这种燃烧系统应用于小缸径直喷柴油机具有良好的推广前景。     

General rate equations and their applications for cyclic reaction networks: multi-cycle systems

The network reduction technique and the Bodenstein approximation of quasi-stationary behavior of reaction intermediates were systematically applied to derive general yield ratio and rate equations for multi-cycle reaction networks in homogeneous catalysis. Dual-cycle reaction networks connected by a linear pathway, multi-cycle networks stemming from the same intermediate, and single-cycle with arbitrary number of pathways between two intermediates were considered. The general yield ratio and rate equations derived in this study are applicable for most enzymatic reactions and for homogeneous catalytic reactions. Examples of homogeneous catalysis were used to illustrate the application of the general yield ratio and rate equations for network elucidation.     

MIMO系统中的分组全分集全码率空时编码

针对未编码的多输入多输出（MIMO，Multi—Input Multi—Output）系统，提出一种复杂度适中的分组全分集全码率（GFDFR，Group—wise Full Diversity Full Rate）空时编码方案。该方案通过在发送端进行天线分组，各组独立编码，减小全分集全码率（FDFR，Full Diversity Full Rate）编码块的大小从而降低系统编解码复杂度；在频率选择性信道中，进一步对子载波分组进行独立编码，获得频率分集（或多径分集），以适中的复杂度在不降低系统分集度的情况下保证了信息的全码率传输，是一种在MIMO信道中极具实用价值的空时编码方案。     

对供电损失率变动规律的分析与预测

通过对历史统计资料的研究,揭示出了供电损失率变动的基本趋势,得出预测的数学模型,同时也获得一种简捷计算供电损失率理论值的方法,便于从宏观角度掌握供电损失率,也可为供电损失管理部门决策提供参考。     

超高速电流反馈集成运放电路与特性

介绍了超高速电流反馈集成运放电路结构，基本特性以及与电压反馈集成运放在性能上的差异。     

Photocatalytic degradation of gaseous perchloroethylene in continuous flow reactors: Rate enhancement by chlorine radicals

The degradation of perchloroethylene (PCE) by UV/TiO₂ photocatalysis in gas phase was studied. The degradation efficiency has been compared in different continuous flow reactors: a photocatalytic tangential reactor (PTR) where the air flows tangentially over the catalytic medium and two photocatalytic filtering reactors (PFR) where the air flows through the porous catalytic medium. The degradation rate shows a linear dependence with the concentration of pollutants (up to 350 mg PCE/N m³) for the PTR, but the degradation was negligible for the PFR. The degradation rate was enhanced by accelerating the chlorine radicals’ formation (by adding HCl in catalytic quantity in the air flow or by PCE over-heating). In these conditions, the oxidation rate constant of PCE in the PFR was about five times higher than that in the PTR, although the mass of catalyst involved in the PFR was about 10 times lower and the contact time was about a 1000 times shorter than that of the PTR. Thus, the catalyst is globally more efficiently used in the PFR, as the mass transfer is not limiting. As a result, a degradation mechanism of PCE, involving the generation of free chlorine radicals, as the first limiting step, has been confirmed.     

单嘴精炼装置真空室内卷渣水模型研究

本文针对长城特殊厂单嘴精炼装置进行了真空室内加渣精炼的卷渣水模型研究。在试验的基础上，首先讨论了真空室内卷渣现象的工艺过程，然后进一步得出了临界吹气量的表达式。研究结果为工业性生产进一步提高钢的质量打下了基础。     

多功能数字信号调制器的研究

本文介绍以８０３１单片机为核心的数字信号调制器的实现原理，由于采用了倍频技术和复合波形合成技术，因而这种数字信号调制器的传输速率在１００－９６００ｂｉｔ／ｓ范围内可调，并且在ＡＳＫ、ＦＳＫ、ＰＳＫ、ＤＰＳＫ、ＱＡＭ等信号调制方式可供选择，以便适用于各种特性的信道。