Fuel Burning Rate Model for Stratified Charge Engine

A zero-dimensional single-zone double-curve model is presented to predict fuel burning rate in stratified charge engines, and it is integrated with GT-Power to predict the overall performance of the stratified charge engines. The model consists of two exponential functions for calculating the fuel burning rate in different charge zones. The model factors are determined by a non-linear curve fitting technique, based on the experimental data obtained from 30 cases in middle and low loads. The results show good agreement between the measured and calculated cylinder pressures, and the deviation between calculated and measured cylinder pressures is less than 5%. The zero-dimensional single-zone double-curve model is successful in the combustion modeling for stratified charge engines.     

微型冷热电联产系统动力装置的参数优化

建立了内燃机的通用数学模型,提出了内燃机的运行经济区.得出了改装后的LJ276M型内燃机的数学模型,并界定了此内燃机的运行经济区的边界范围,分析了此内燃机的运行优化曲线和最佳运行工况点.针对动力系统的冷热电、热电和供电3种操作模式,分别建立了能量转换数学模型,优化了动力装置的内燃机/变速箱传送比ies、电动机/变速箱传送比ims和电动机/内燃机传送比ime.结果表明：在冷热电模式下,ies和ims的优化值分别为2.9和1;在热电模式下,当动力系统需求负荷小于内燃机运行经济区的下限值时,ime取1,而当动力系统需求负荷超过内燃机运行经济区的下限值时,ime取0.85;在供电模式下,ims的最优值取2.5.     

柴油机燃油喷射系统的仿真计算及分析

较全面地分析了柴油机燃油喷射系统仿真计算的影响因素，给出了仿真计算的基本数学模型。研究并分析了传统和电控喷油系统仿真计算的特点，分析了现有计算模型的现状及部分缺陷，并就其发展提出了一些建议。     

水上交通加权安全评价中权重向量的异常分析

为提高指标权重在水上交通安全评价中的准确性,提出一种基于DBSCAN算法的权重向量异常分析方法.该方法选取加权评价法为研究对象,以DBSCAN算法为检测方法,对水上交通加权安全评价中的权重向量进行异常分析.实例表明,在130组数据中,异常权重向量共3组.从数据分布情况看,异常向量与正常向量有比较明显的差异,说明此方法能有效识别异常向量,是可行的.该方法对权重向量集进行分析后,可防止异常权重向量的干扰,提高评价结果的质量.     

垂直搜索引擎探索

随着网页信息量的增大,通用搜索引擎已不能满足用户需求,因此,出现了垂直搜索引擎,主要介绍了垂直搜索引擎的定义,垂直搜索引擎与通用搜索引擎搜索的区别,以及垂直搜索引擎评估、应用和发展方向.     

A study of results overlap and uniqueness among major Web search engines

The performance and capabilities of Web search engines is an important and significant area of research. Millions of people world wide use Web search engines very day. This paper reports the results of a major study examining the overlap among results retrieved by multiple Web search engines for a large set of more than 10,000 queries. Previous smaller studies have discussed a lack of overlap in results returned by Web search engines for the same queries. The goal of the current study was to conduct a large-scale study to measure the overlap of search results on the first result page (both non-sponsored and sponsored) across the four most popular Web search engines, at specific points in time using a large number of queries. The Web search engines included in the study were MSN Search, Google, Yahoo! and Ask Jeeves. Our study then compares these results with the first page results retrieved for the same queries by the metasearch engine Dogpile.com. Two sets of randomly selected user-entered queries, one set was 10,316 queries and the other 12,570 queries, from Infospace’s Dogpile.com search engine (the first set was from Dogpile, the second was from across the Infospace Network of search properties were submitted to the four single Web search engines). Findings show that the percent of total results unique to only one of the four Web search engines was 84.9%, shared by two of the three Web search engines was 11.4%, shared by three of the Web search engines was 2.6%, and shared by all four Web search engines was 1.1%. This small degree of overlap shows the significant difference in the way major Web search engines retrieve and rank results in response to given queries. Results point to the value of metasearch engines in Web retrieval to overcome the biases of individual search engines.     

国内可视化搜索引擎研究进展:架构体系与关键技术

本文介绍了可视化搜索引擎内涵、核心内容和研究框架,并从架构体系、关键技术两方面阐述了国内可视化搜索引擎研究进展。     

基于科研项目的研究生海洋生态学课程教改

研究生教育的根本目标是培养学生的科研能力和创新能力。结合现有科研项目,对研究生海洋生态学课程教学内容、教学方法和考核方式进行了改革。实现教学与科研相结合,以科研带动教学,注重培养研究生的科研能力和创新能力,以满足社会经济的发展对高层次专业人才的需要。     

高职高专轮机英语词汇教学策略

文章分析了轮机英语作为专门用途语言的词汇特点,并针对其词汇特点提出在实际教学中应使用的词汇教学策略。     

基于CGE模型的海洋生态补偿宏观经济效应

近年来,海洋经济的快速发展导致海洋生态坏境面临的压力越来越大。为保护海洋生态系统,实现海洋自然资源的可持续利用,亟需建立相应的海洋生态补偿机制,并探索生态补偿的标准问题。本文通过编制2017年中国宏观经济社会核算矩阵,构建中国宏观经济可计算一般均衡模型,模拟了征收不同程度的海洋生态补偿税对经济活动的影响。研究发现：①在征收生态补偿税的情形下,将政府收入增加的部分作为海洋生态补偿的专项资金,能够有效提高海洋生态补偿量。在生态补偿税设置为增值税的5%的情况下,海洋生态补偿量较初始情形相比,提升了4.07倍。②生态补偿税的征收会引起居民收入、企业收入、国外储蓄和国内生产总值的下降,对经济发展产生一定的阻碍作用。其中,居民收入和国外储蓄受影响较大,企业收入和国内生产总值受影响较小。因此,需要制定合理的生态补偿标准和政策,实现生态环境和社会经济的协调发展。