THE SIZE EFFECT OF THE FRACTURE ENERGY OF CONCRETE TESTED BY THREE POINT BENDING

This paper ainalyses the size effect of the fracture energy of concrete tested bythree point bending. It is shown that positive errors of test results of fracture energy increase,ornegative errors decrease with increasing of the specimen ize. The phenomenon is one of main causesresulting in the size effect of fracture energy.     

Energy Efficiency Analysis of Heating System in the Birdhouse

In this paper the problem of energy consumption and environment in the birdhouse is introduced and the reconstructive measures aiming at energy savings are recommended. The measures include the limitation of temperature region, reconstruction of the building envelop and using the sunny board at the south side of the birdhouse roof. Finally, the energy efficiency of the reconstructive project is estimated.     

Optimum Planting System for Energy Saving and Healthy Demanded

It is proved that planting is effective to improve environment both indoor and outdoor resulted from the functions of plants to clean air and save energy. So the contradiction between saving energy and comfort,healthy demanded by people can be solved by planting. The planting have being emphasized and expanded during recent years,but in the planting plan,just the function of beautifying the environment is concerned and the function of ecological and saving energy are neglected. The analysis on the ooptimum system of planting is to make the planting system as an organic composition in the effectiveness structure and space layout of the city. Based on the study on equivalent relation of different effects on environment, the optimum system of planting structure will be determined in order to achieve the integrated effects of planting on environment.     

Discussion about Saving Energy in Refrigeratory

Food refrigeration is regarded as a high energy consuming trade. Under the long period system of state operated enterprise,there are many phenomenons of ignoring energy management and wasting energy. Energy consuming is not very clear for production.Consuming in our country is far more than the international standard and there is a distance between the middle_westland and the eastland. As a enterprise that faces the international market,it is important for it to strength the management so that the cost can be reduced. Considering those phenomenons of ignoring energy management and wasting energy in refrigeratory at present, some measures such as improved the unreasonable operation process, strengthening the energy management and automation to realize automatizing operation are improved to reduce the cost for refrigeratory trades.     

基于KPCA-WLSSVM的建筑能耗预测模型

为降低建筑能耗影响因素间复杂相关性对模型性能的影响,建立了一种基于KPCA-WLSSVM的建筑能耗预测模型。利用核主元分析(KPCA)对输入变量进行数据压缩,消除变量之间的相关性,简化模型结构;进一步采用加权最小二乘支持向量机(WLSSVM)方法建立建筑能耗预测模型,同时结合一种新型混沌粒子群-模拟退火混合优化(CPSO-SA)算法对模型参数进行优化,以提高模型的预测性能及泛化能力。通过将KPCA-WLSSVM模型方法应用于某办公建筑能耗的预测中,并与WLSSVM、LSSVM及RBFNN模型相比,实验结果表明,KPCA-WLSSVM模型方法能有效提高建筑能耗预测精度。     

地源热泵技术在中国温室设施中的应用探讨

当前在中国温室设施中应用和推广地源热泵技术尚存在诸多不利因素,大大限制了该项技术在设施农业领域中的发展。为探寻合理的解决途径,对地源热泵空调系统的关键技术和其在中国的发展概况进行了相关的阐述和分析,并以中国农业大学上庄实验站已经建成使用的地下水式温室地源热泵空调系统为实例,介绍该系统的组成、工作流程、性能参数和使用情况,探讨温室地源热泵空调系统在推广和使用中可能出现的投资较高,长时间运行性能不稳定等问题,分析其原因并提出相应的对策建议。     

生物质气体燃料概述与展望

论述了生物质气体燃料的种类以及生产各种气体燃料的相应技术及其国内外发展概况和存在问题.生物质气化方面国内外有产业化实例;生物发酵制氢大多数处于实验阶段,关键是培育高效产氢发酵菌种、进一步提高系统的产氢能力、降低生产成本;厌氧发酵制取沼气生产技术比较成熟,在其生产过程中不消耗其它能源、没有环境污染、而且可降解各种有机废弃物,是目前最有希望的生物质能源之一.     

农作物秸秆资源的开发与利用

我国每年秸秆产量约5.7亿t,这是一项巨大的资源.为此,从燃料、肥料、工业原料和饲料4个方面论述了秸秆开发利用的方法和原理,指出了秸秆资源利用的出路在于饲料业;同时,强调做好秸秆资源的开发和利用,对于解决我国饲料粮紧缺状况,缓解能源、林木减产的压力具有重要意义.     

甘肃能源型生态农业推广效益分析

本文就近年来甘肃以沼气为纽带的能源型生态农业模式的推广情况及其所带来的社会、经济和生态效益做一简要分析.     

一种新的能量叠加点火系性能匹配研究

在能量叠加点火系电路分析的基础上，对其进行了匹配发动机的试验研究。试验结果表明，能量叠加点火系可有效改善发动机的点火性能，从而使发动机的动力性能提高约2％～5％，经济性能改善4％左右，怠速排放特性改善幅度达10％左右，外特性排放改善幅度达8％～20％；与传统点火系相比，还可以使发动机最低稳定运转速度降低30％左右，同时使发动机的起动变得迅速、容易。试验结果与理论分析完全吻合，证明了能量叠加点火系确实可以缩短可燃混合气的着火延迟期，有利于混合气的快速燃烧，这种技术特别适合于稀薄燃烧与快速燃烧系统。