HYDRAULIC CHARACTERISTICS OF SLIT-TYPE ENERGY DISSIPA-TERS

Slit-Type Energy Dissipater(STED) has been a kind of important devices for energy dissipation.The flow through the STED is longitudinally extended and the velocity is decreased by means of the cross-section increase of the flow,which is closely related to geometric and hydraulic parameters of the STED.Therefore,it is necessary to investigate and control the hydraulic condi-tions through the STED,including the nappe section form,the conversion condition,and the effect of energy dissipation with the geometric and hydraulic parameters.In the present work,"I-type" and "T-type" nappe forms were experimentally classified,the con-version conditions of the nappe forms were empirically provided,and the effects of geometric parameters of the STED on energy dissipation were roughly analyzed.It is concluded that the contraction angle of the STED is a key factor influencing the hydraulic characteristics of the STED.     

Metabolic and cardiovascular responses to exercise with caffeine

The effect of caffeine on circulation and metabolism was studied during a discontinuous maximal oxygen uptake (VO₂ max) test on a bicycle ergometer. Eight male subjects were chosen for their minimal use of caffeine of which six normally did not ingest caffeinated beverages. Two caffeinated and two decaffeinated (control) trials were administered to each subject following double-blind and counterbalanced testing procedures. One hour before exercise, subjects ingested decaffeinated coffee with or without 350 mg of caffeine anhydrous added. Cardiac output (Q) was measured by a C0₂ rebreathing technique. Compared to control trials, caffeine increased the VO₂ max by an average of 140ml min?¹ (p <0-0·5)l. In addition, during caffeine trials, the average maximal heart rate (HR max) was elevated by 5 beats min^?1 (p<0·01). There were no other statistically significant changes in metabolic (VO₂ and R) and cardiovascular (Q, HR, SV and (a-v) 0₂ diff) variables during either submaximal or maximal exercise. Performance, as measured by total exercise time on the VO₂ max test, was not significantly different (p>0·05). It was concluded that caffeine has a small physiological but a statistically significant effect on VQ₂ max and HR max. During submaximal exercise, caffeine did not significantly effect the cardiovascular system.     

基于PCA降维和优化核参数SVM的电能质量扰动分类

首先对采样信号用db4小波进行10层的多分辨分解,提取扰动信号各层能量与标准信号的能量差作为特征向量;然后用PCA对特征向量进行降维,取3维数据作为分类的特征向量,并将训练集采用交叉验证的方法自适应选择最优参数,并构造训练集模型;最后将测试集数据代入训练集模型进行分类测试.测试结果表明,在PCA降维后可以实现扰动的分类:分辨率高;抗噪能力强;适用于电能质量扰动的分类.     

炼油企业综合能源效率评价指标体系的研究

利用3E评价模型构建炼油企业的综合能源效率评价指标体系,通过运用BP神经网络确定评价指标的权重,权重最高的指标是资源循环利用率,其次是能源强度。利用2010年M企业和炼油行业的数据进行神经网络训练,结果显示,M企业的综合能源效率评价结果明显优于行业水平。     

低碳酒店发展策略探析

低碳旅游是顺应全球低碳经济的发展而提出的,低碳酒店作为低碳旅游的重要部分,在当代社会也发挥着重要的节能减排作用。通过对国内低碳酒店的现状调查,可以发现在酒店方面实行节能减排还具有很大的潜能,文章提出了一些低碳酒店发展策略,以期为国内酒店的低碳发展提供参考。     

河南省建筑业投入与产出分析

选取2010 ～2011年的统计数据,依据DEA数据包络评价分析方法,以建筑业从业人员总数、固定资产投资总额、建筑业从业人员工资总额、建筑业总产值以及竣工房屋面积为评价指标,对河南省下属的17个省辖市、10个省直管市（县）的投入产出整体效率及各投入要素效率进行了测算和分析.对各地区建筑业发展的投入、产出不足之处予以了说明,同时对这些地区的竞争力作了详细的分析和论证.     

LNG接收站冷能利用方案

浙江液化天然气(Liquefied Natural Gas,LNG)接收站项目一期设计生产能力为300万t/a,可利用的冷能相当于6亿度电。冷能利用是工艺优化、节能环保和经济效益最大化的重要步骤。本文通过对冷能利用方案的原料、市场、冷能利用率、与LNG冷能工艺的匹配性、投资及回报等进行对比分析,选择合适的冷能利用方案,为其他LNG接收站项目提供参考。     

探析成人二语习得过程中语言输出的途径

在我国成人教育迅速发展的步伐中,对成人二语习得的研究日益增加。本文提出了当今成人英语教育和学习中只重视语言输入而忽视语言输出的不足,分析总结语言输出的重要性以及对成人英语学习影响,从四个方面探讨了成人英语学习中有效的语言输出途径,以求有效地增加成人英语学习中的语言输出,切实提高成人二语习得的效果。     

半刚性钢框架的抗震性能研究综述

半刚性连接节点钢框架由于节点本身的非线性受力性能,使框架内力发生重分布,提高了钢框架整体的滞回性能,大大增强了结构的抗震能力.因此,半刚性钢框架的研究对工程结构抗震具有重要意义.     

我国报废汽车回收利用行业产值预测

基于历史数据变化规律,运用回归分析法对2012-2016年间我国汽车保有量和新增量,汽车报废量以及报废汽车回收利用行业产值进行了预测。