发动机分析仪的组成及其计算机测控系统的研究

本文以华燕HFZF2000型发动机分析仪为例，介绍发动机分析仪的组成和计算机系统测试（CAN）的特点，利用华燕HFZF2000型发动机分析仪对发动机点火波形特征及其故障诊断，分析影响发动机的单缸转速降和点火性能等参数。     

The performative shift: middle leadership ‘in the line of fire’

ABSTRACT

State school inspection in Norway is currently changing with targeted schools becoming subject to more complex methods of inquiry. Not only school principals but middle leaders are exposed to this shifting system, for the latter are in the frontline of their schools’ everyday practices. The article examines how state school inspection is used as means of controlling legal compliance, as well as evaluating the formative assessment routines and practices of schools, middle leaders, and individual teachers. Drawing on the concepts of accountability and performativity, field observations of inspectors interrogating department heads in primary education are analysed. The empirical study demonstrates how use of standardised rubrics steer the inspection process in schools, aiming more towards completing on task, rather than supporting middle leaders in their struggle to comply with legal standards. During such interrogation, the department heads comply with the system, and are at the same time open towards the inspectors’ questioning concerning the school’s lack of fully implemented routines.     

环境中邻苯二甲酸酯样品前处理研究进展

回顾近十年来环境中邻苯二甲酸酯类化合物分析方法的研究进展，比较环境中大气、水及土壤等不同样品的前处理技术和检测方法，介绍固相萃取和固相微萃取等新型样品前处理技术在水样分析中的应用研究。     

高职汽车检测与维修专业课程体系的构建

课程改革是高职教学改革的重点和难点,本文针对目前我国高职汽车专业的发展现状,提出以职业能力为中心来构建模块式课程体系,遵循适应性、应用性、产学结合等原则,将课程分为理论教学模块和实践教学模块,使学生既动脑又动手,理论、实践融会贯通,知识与技能同步养成.     

气相色谱法测定花生油掺伪的方法研究

用气相色谱法测定了花生油和一些常见植物油的脂肪酸组成及其含量,使用添加法在花生油中掺入不同种类、不同浓度的植物油,并进行了相关分析.发现油中脂肪酸组成及其特征组分的变化成线性规律,由此做出工作曲线,可快速定性、定量掺伪油,且掺伪量的最低检出限可达到5%.     

英国学校督导类型述评

为了提高学校督导工作的效率，英国采取了全面督导和短期督导两种方式。在对这两种督导类型的适用对象和实施过程进行比较并分析两者的相互关系的基础上，做出评价，并由此提出一些经验教训，以供我国督导工作参考。     

气相色谱法测定电泳漆中乙二醇乙醚质量分数的不确定度分析

对气相色谱内标法测定电泳漆中乙二醇乙醚质量分数的整个测定过程进行研究,系统分析该法测量结果的不确定度来源,对不确定度的各个分量进行评估和合成。结果表明,峰面积的重复性测量是影响乙二醇乙醚质量分数测定不确定度的主要原因。当乙二醇乙醚测定结果为3.306%时,扩展不确定度为0.300%。该样品中乙二醇乙醚质量分数测定结果表示为ωydm=3.306%±0.300%（k=2,P=95%）。     

生物柴油（来自废弃玉米油）中三种脂肪酸甲脂的气相色谱分析

建立了用废弃玉米油制备的生物柴油（以离子液体为催化剂）中棕榈酸甲酯、油酸甲酯、亚油酸甲酯的气相色谱分析方法.采用PEG-20M填充柱,氢火焰离子检测器,对色谱条件进行了优化.当柱温为170℃,汽化室的温度为230℃,检测器温度为250℃,载气流速压力为35 mL/min,空气流速压力为450 mL/min,氢气流速压力为50 mL/min时,3个组分在55 min内达到了分离,效果良好.     

Growth rate, catalase and superoxide dismutase activities in rock carp (Procypris rabaudi Tchang) exposed to supersaturated total dissolved gas

Total dissolved gas supersaturation (TDGS) appears when the pressures of gases in a solution exceed the barometric pressures. TDGS is often caused by flood discharge at dams. It may lead to gas bubble disease (GBD) for fish and biochemical responses of selected fish and other aquatic organisms. The purpose of this study was to determine the impact of long-term TDGS levels on the growth and biochemical responses of rock carp (Procypris rabaudi Tchang) dwelling in the upper reaches of the Yangtze River. Three-year-old rock carp were exposed to TDGS levels at 100%, 104%, 108%, 112%, and 116% for 42 d. Samples were taken every 7 d after the start of the trial in order to determine catalase (CAT) and superoxide dismutase (SOD) activities in gill and muscle tissues. Samples were taken at Days 0 and 42 of exposure to determine growth rate. Little effect was found on growth rate in all treatment groups. SOD and CAT activities varied in different tissues, according to time of exposure and TDGS levels. The biochemical response of fish exposed to TDGS was more obvious in gill tissue than in muscle tissue. Surveys of SOD and CAT activities in different tissues offer important information about the effect of TDGS on the rare fish in the Yangtze River, and may help evaluate the risk to the aquatic eco-environment and aquatic ecosystem in the downstream of the Yangtze River.     

含CO2的蒸汽凝结换热特性

基于双边界层理论,建立含CO₂的蒸汽在竖直平板表面凝结换热模型。CO₂的存在极大恶化了凝结换热性能。在CO₂浓度一定时,随着过冷度的增加,热流密度逐渐增大,凝结换热系数逐渐减小,界面温度近乎线性降低;随着CO₂浓度的增大,凝结换热系数迅速降低,界面温度逐渐增大。CO₂的存在使得凝结液膜表面形成一层气膜,随过冷度的增大,液膜厚度逐渐增加,气膜厚度逐渐减小,但气膜厚度要比液膜厚度大一个数量级;随着CO₂浓度的增大,液膜厚度与气膜厚度均在减小,但气膜热阻与液膜热阻的比值逐渐增大,并且在高浓度CO₂情况下,气膜热阻成为主导热阻。