用蒙特卡罗方法求平均指示压力

蒙特卡罗方法可用随机投点法及期望估计法在计算机上的模拟求积仪，对示功图进行积分从而为平均指示压力的求取提供了新的方法。并通过计算实例，表明选取适当的随机数列和投点数后，可取得较高计算精度。     

Combustion analysis of a spark ignition engine fueled with gaseous blends containing hydrogen

This paper presents the combustion characteristics of a naturally aspirated spark ignition engine, intended for installation in vehicles, fueled with different hydrogen and methane blends. The experimental tests were carried out in a wide range of speeds at equivalence ratios of 1, 0.8 and 0.7 and at full load. The ignition timing was maintained for each speed, independently of the equivalence ratio and blend used as fuel. Four methane-hydrogen blends were used. In-cylinder pressure, mass fraction burned, heat released and cycle-by-cycle variations were analyzed as representative indicators of the combustion quality. It was observed that hydrogen enrichment of the blend improve combustion for the ignition timing chosen. This improvement is more appreciable at low speeds, because at high speeds hydrogen effect is attenuated by the high turbulence. Also, hydrogen addition allowed the extension of the LOL, enabling the engine to run stable in points where methane could not be tested. The main inconvenience detected was the high NO_x emissions measured, especially at stoichiometric conditions, due mainly to the increment in the combustion temperature that hydrogen produces.     

Effect of methanol gasoline blended fuels on the performance and emissions of SI engine

This article presents experimental results of the effect of methanol gasoline blends as alternate fuels for the spark ignition (SI) engine. As the cost of the gasoline is periodically increasing the quest for the alternative fuels are evolved with which the emissions are reduced along with improved engine performance. A set of experiments have been conducted to investigate the effect of gasoline methanol blends in methanol percentages of M5, M10 and M15 on the engine performance and emissions. A significant reduction in emissions is observed with methanol blends compared to the standard gasoline with improved engine performance and emission characteristics. The fuels blends ranging from M10 to M15 have been found suitable for reduced emissions and improved engine performance.     

物理学中的自然单位方法

分析了物理学中自然单位的特点，用自然单位方法给出了原子物理学中玻尔理论的全部结果．     

SI住宅干式内装系统架空地面和地暖干式铺法施工技术

SI住宅干式内装系统架空地面施工技术是在地板下采用CP地脚螺栓支撑,架空空间内铺设机电管线。与一般的直铺地板相比,本方法地面温度相对较高,地面干燥,温度、湿度适中。在架空地板施工的基础上,实施地暖干式铺法施工。地暖干式铺法施工由基层聚苯乙烯泡沫板、中间层导热板及加热管、顶层水泥承压板组成,用尼龙胀塞与底层地面进行固定。将以前由工人在现场自由安装的管道敷设到预制好的衬板中,规整有序,同时减少施工过程中对材料的损坏。     

SI engine assessment using biogas,natural gas and syngas with different content of hydrogen for application in Brazilian rice industries: Efficiency and pollutant emissions

After Asia, Brazil is the world's largest rice producer. During the processing of the grain, large amounts of husk are generated, corresponding to 22% of its weight. On the other hand, in the process of parboiling, in turn, the final result is considerable volumes of effluents rich in organic matter, generating large amounts of methane gas through anaerobic treatment. Therefore, the SI engine can operate with mixtures of biogas and syngas, generating electricity and heat in the Brazilian rice industries. In addition, it reduces the emissions of polluting gases that are generated with a direct burning of the husks instead of their gasification, as well as the use of methane gas. Accordingly, in this work, it was used the spark-ignition engine operating with one of the typical biogas and syngas compositions generated in the rice industries, named Bio65 (containing 65% of CH₄ by vol.), syngas1 (containing 18,3% of H₂ by vol.), and syngas2 (containing 13,5% of H₂ by vol.), respectively. Additionally, the tests with natural gas as a reference fuel have been performed. It was evaluated the emissions of polluting gases such as CO, NO_x and HC, as well as the thermal and electrical efficiency of all tested fuels. An important result that could be observed was that for both natural gas and biogas fuel, the increase in excess ratio (λ) value from 1 to 1.5 led to lower NO_x and CO emissions, even if with increased HC emissions. On the other hand, the Indicated Specific Energy Consumption increased to all the fuels tested in lean conditions in almost all ignition advances angles. The research tried to show that biogas and syngas can be used in parboiling rice industries, taking the advantage of the generated gases for energy self-sufficiency as well as reducing emissions.     

机顶盒解复用器适配层的设计与实现

本文提出了一套机顶盒解复用器的设计和相关的接口函数 .它具有完备 ,简单 ,通用 ,易用的特点 ,支持应用程序的各种要求 ,数目少 ,抽象程度高 ,主要描述应用程序的要求 ,并且从 MPEG和 DVB标准出发 ,不涉及解复用器操作的细节 ,可在多个硬件平台上使用 ,为应用程序提供了一个稳定的开发环境 .能够很好地支持应用程序的开发 .文中详细地介绍了它的指导思想 ,概念 ,结构 ,所提供的服务 .同时 ,还介绍了实现这些函数的关键算法 .     

半绝缘GaAs的表面光伏谱研究

利用表面光伏法（ＳＰＶ）研究了半绝缘ＧａＡｓ（ＳＩ－ＧａＡｓ）的缺陷态,通过加直流光偏置测量了室温下带边以下的光伏响应,发现带隙内缺陷态的光伏向应主要是由于表面复合而在样品表面形成协流子浓度梯度引起的,通过实验表明ＳＰＶ是一种对ＳＩ－ＧａＡｓ晶片表面质量进行检测的非常灵敏的无损检测方法。     

Multi-dimensional modelling of spray,in-cylinder air motion and fuel-air mixing in a direct-injection engine

In this work, three-dimensional fuel-air mixing inside a conventional spark ignition engine cylinder is simulated under direct injection conditions. The motivation is to explore retrofitting of conventional engines for direct injection to take advantage of low emissions and high thermal efficiency of the direct injection concept. Fuel-air mixing is studied at different loads by developing and applying a model based on the Lagrangian-drop and Eulerian-fluid (LDEF) procedure for modelling the two-phase flow. The Taylor Analogy Breakup (TAB) model for modelling the hollow cone spray and appropriate models for droplet impingement, drag and evaporation are used. Moving boundary algorithm and two-way interaction between both phases are implemented. Fuel injection timing and quantity is varied with load. Results show that near-stoichiometric fuel-air ratio region is observed at different locations depending on the load. The model developed serves to predict the fuel-air mixing spatially and temporally, and hence is a useful tool in design and optimization of direct injection engines with regards to injector and spark plug locations. Simulations over a range of speed and load indicate the need for a novel ignition strategy involving dual spark plugs and also provide guidelines in deciding spark plug locations.     

数字电视分前端系统集成的讨论

讨论地市级分前端系统构成与维护，分析不同节目源的特点及后续处理方法，结合本地节目插入对技术指标保障作具体分析，并就EPG信息的统一规划进行细致论述。