A jet-stirred reactor and kinetic modeling study of ethyl propanoate oxidation

A jet-stirred reactor study of ethyl propanoate, a model biodiesel molecule, has been carried out at 10 atm pressure, using 0.1% fuel at equivalence ratios of 0.3, 0.6, 1.0 and 2.0 and at temperatures in the range 750-1100 K with a constant residence time of 0.7 seconds. Concentration profiles of ethyl propanoate were measured together with those of major intermediates, ethylene, propanoic acid, methane and formaldehyde, and major products, water, carbon dioxide and carbon monoxide. This data was used to further validate a previously published detailed chemical kinetic mechanism, containing 139 species and 790 reversible reactions. It was found that this mechanism required a significant increase in the rate constant of the six-centered unimolecular elimination reaction which produces ethylene and propanoic acid in order to correctly reproduce the measured concentrations of propanoic acid. The revised mechanism was then used to re-simulate shock tube ignition delay data with good agreement observed. Rate of production and sensitivity analyses were carried out under the experimental conditions, highlighting the importance that ethylene chemistry has on the overall reactivity of the system.     

集成化门户WJPortal开发与应用

针对现有门户在Portlet集成、访问模式、远程调用等方面存在的不足。结合WSRP框架,设计并开发了一个符合JSR168标准的开放式信息门户WJPortal。该门户采用远程Portlet代理、Portal容器和WSRP Stub等技术实现,通过Client、Interface、Provider三大组件的开发,为企业信息门户的开发提供了一个更加统一、便捷、开放、灵活的框架结构。基于WSRP门户构建了一个水利信息门户服务平台,给出了应用实例,提高了水利业务Portlet的集成能力。     

基于JES平台的典型标准门户组件的设计与实现

介绍了企业门户技术与门户组件技术以及门户组件标准的发展,研究了门户页面的产生过程,将门户组件标准定义的门户组件生命周期模型化,基于JES平台构建典型标准门户组件,并对其生命周期进行分析.     

基于JetSpeed 的多portlet 流程协作机制研究与实现

当前门户的功能定位已经从传统的信息集成转向应用集成。门户环境中应用间的进一步集成实际上表现为Portlet 协作问题。在分析现有协作方法的基础上,遵循jsr286 规范,提出了可扩展的多Portlet的流程协作框架,并结合开源门户产品JetSpeed2.0 进行开发,从而解决了数字校园建设中利用门户实现应用交互协作和个性化信息服务的关键问题。     

网格门户开发研究

网格门户担当着网格大门的角色,使人们能更顺利地使用网格资源.介绍网格门户的发展历程,重点阐述了开发第二代网格门户的技术规范和开发方法,分析网格门户的发展趋势.     

2FSK灵巧干扰技术

通过对FSK信号接收解调薄弱环节的分析,提出实现灵巧干扰的可能途径,并对各种相关方法进行了实验验证和比对,证实了该方法的有效性,对2FSK数传通信电台的干扰结果表明灵巧干扰可比噪声干扰节省5dB的干扰功率。     

基于JSR180的手机SIP功能的开发

本文介绍了JSR180资源开发包,分析了手机SIP的会话建立和拆除过程,开发了基于JSR180的短信收发程序,并给出了WTK模拟结果。本文对开发手机SIP功能具有参考作用。     

Experimental study and detailed kinetic modeling of the effect of exhaust gas on fuel combustion: mutual sensitization of the oxidation of nitric oxide and methane over extended temperature and pressure ranges

New experimental results were obtained for the mutual sensitization of the oxidation of NO and methane in a fused silica jet-stirred reactor operating at 1-10 atm, over the temperature range 800-1150 K. Probe sampling followed by on-line FTIR analyses and off-line GC-TCD/FID analyses allowed the measurement of concentration profiles for the reactants, stable intermediates, and final products. Detailed chemical kinetic modeling of the experiments was performed. An overall reasonable agreement between the present data and modeling was obtained, whereas previously published models failed to properly represent these new data. According to the proposed model, the mutual sensitization of the oxidation of methane and NO proceeds through the NO to NO₂ conversion by HO₂ and CH₃O₂. The modeling showed that at 1-10 atm, the conversion of NO to NO₂ by CH₃O₂, is more important at low temperatures (800 K) than at higher temperatures (850-900 K), where the reaction of NO with HO₂ dominates the production of NO₂. The NO to NO₂ conversion is enhanced by the production of HO₂ and CH₃O₂ radicals from the oxidation of the fuel. The production of OH resulting from the oxidation of NO promotes the oxidation of the fuel: NO + HO₂ ? OH + NO₂ is followed by OH + CH₄ ? CH₃. At low temperature, the reaction further proceeds via CH₃ + O₂ ? CH₃O₂, CH₃O₂ + NO ? CH₃O + NO₂. At higher temperatures, the production of CH₃O involves NO₂: CH₃ + NO₂ ? CH₃O. The sequence is followed by CH₃O ? CH₂O + H, CH₂O + OH ? HCO, HCO + O₂ ? HO₂, and H + O₂ ? HO₂. ? CH₂O + H, CH₂O + OH ? HCO, HCO + O₂ ? HO₂, and H + O₂ ? HO₂.     

多音干扰信号对直扩通信系统伪码捕获过程的干扰效果分析

传统的对直扩通信系统干扰样式分析一般认为多音干扰能量分散,干扰效果不如单音干扰理想。从组成多音干扰的每一个单音干扰分量入手,分析其干扰效果,进而得到多音干扰的总体干扰效果。仿真结果表明:在有用信号频率无法准确侦察的情况下,多音干扰能够有效提高干扰范围,干扰效果较好;在确定多音干扰频率分布时,应该充分考虑有用信号频率的分布,做到在其频率范围内的任意有用信号都有一个或者多个单音干扰分量能够对其有效干扰;在确定多音干扰的功率分配时,应该充分考虑有用信号频率的概率分布,对于干扰有用信号频率出现概率较大区域的单音干扰分量,其功率也应该较大。