基于车桥耦合振动分析的桥梁损伤诊断方法评述

车辆通过桥梁时,桥梁和车辆的动力响应都包含桥梁结构模态或者几何参数信息,对它们进行分析能识别桥梁的模态参数和损伤。结合国内外最新研究成果,综述基于车桥耦合振动分析的桥梁结构损伤识别技术,并与传统识别方法进行比较。指出其优缺点;详细介绍基于灵敏度分析和模型修正的方法、基于结构刚度搜索的方法、利用车辆响应傅立叶变换识别桥梁频率的方法、利用车激桥梁响应的小波变换识别桥梁模态参数的方法以及综合利用车辆和桥梁响应识别桥梁损伤的方法等5种参数识别与损伤诊断方法的基本原理,并总结上述方法的实施步骤和应用时应该注意的问题;指出了该领域的关键问题和进一步的研究方向。     

安全氛围对企业安全行为的影响研究

国外大量研究表明,安全氛围调查在改进企业的安全行为方面有积极的作用,为组织制订未来的安全政策提供依据。本研究通过查阅文献、国外类似的诊断调查工具及软件,根据所提出的理论假设,采用线性结构方程建模的方法,构建了本研究的LISREL理论模型,并设计了相应的调查问卷和量表。从所建立的安全氛围的三个构面(安全管理、安全认知、安全态度)入手探讨企业的安全氛围对企业的安全行为(两个构面:安全执行、安全处理)的影响。本研究采用问卷调查的方式采集数据,将所得资料用SPSS11.0和LISREL8.3软件来分析处理和检验研究假设,研究结果为实证单位改进企业的安全行为提供了帮助。     

国有重点煤矿企业安全科技人才现状研究

依据对我国国有重点煤矿企业抽样调查的结果,着重对国有重点煤矿企业安全科技人才的总量、密度、结构、流失等进行了系统的分析,并与美国煤炭行业的人才状况进行了比较分析。笔者在此基础上,给出了国有重点煤矿企业安全科技人才现状的基本评价,国有重点煤矿企业安全科技人才断层已经出现,安全科技人才总量严重不足,人才的问题已经开始制约煤炭行业的发展,尤其是严重制约着煤炭行业建立安全生产长效机制;对进一步加强和优化国有重点煤矿企业安全科技人才队伍建设提供了可靠的依据,具有重要指导意义。     

燃烧、爆炸过程复杂性行为的非线性动力学—突变燃烧学、突变爆炸学(Ⅱ)(上)

针对燃烧,爆炸学中存在的大量非连续性现象,提出了突变燃烧学和突变爆炸学的概念,指出了突变燃烧学和突变爆炸学的基本任务和主要研究内容。提出了单颗碳粒着火和熄火现象的突变机理。     

区域资源开发的系统转换理论

作者在分析资源与资源功能的基础上,以区际资源功能互补转换和区内资源结构对应转换为主题,论述了有关“区域资源开发的系统转换理论”的新思想。     

Estimation of emission reduction potential in China’s industrial sector

The industrial sector is usually the largest economy sector for carbon emissions in many countries, which made it the sector with greatest potential for carbon reduction although the process duration might be very long. Studying the potential of industrial emission reduction has great significance in estimating the carbon emission peak of China on the one hand, and adjusting its strategy in international climate change negotiations. By employing the economic accounting method, this article estimates the emission reduction potential of China’s Industrial sector for the period of 2010–2050. It reveals that, taking 2030 as the year when the emission reaches the peak, the total reduction can be 8.38 billion tons (bts) for the period of 2010–2030, with 3.12 bts from structural reduction while 5.26 bts from intensity reduction. Afterwards, reduction will continue with a total amount of 6.59 bts for the period of 2030–2050, where the structural reduction accounts for 2.47 bts, and intensity reduction 4.115 bts. If both industrial and energy consumption structures are improved during the above period, the reduction potential can be even greater, e.g. the emission peak can arrive five years earlier (in the year of 2025) and the peak value can decline by about 8% as compared to the original estimation. Reviewing the trajectory of emission changes in developed countries indicates that the industry sector can contribute to the overall reduction targets through the dual wheels of structural reduction and intensity reduction, even beyond the emission peak. This article concludes with the following policy suggestions. (1) Our estimation on the emission peak of the industrial sector suggests that China should avoid any commitment earlier than 2030 on the timeline of the overall emission peak; (2) the great potential of industrial emission reduction can improve the situation of China in climate change negotiation, where the intensity reduction can serve as an important policy option. (3) Reduction potential can be further enhanced through technology advancement, which requires furthering of market oriented reforms and improvement of institutional design. (4) To secure the reduction effects of the industrial structure adjustment, the balanced development among different regions should be encouraged in order to avoid the reverse adjustment caused by industrial transferring. (5) International cooperation promoting the application and development of industrial emission reduction technologies, including carbon capture, utilization and storage, should be encouraged.     

Thailand’s economic growth and structural development projections in the context of environmental control

Projections for 20 years of economic growth and change in the structure of the Thai economy were made for 180 sectors using a computable general equilibrium (CGE) model to compare the following four scenarios: (1) standard growth with infinite supply of factors, (2) finite land supply, (3) fixed use of agricultural chemicals, and (4) combined finite land supply with fixed use of agricultural chemicals. The computable projections suggest that the economic cost of hypothetical environmental control in agriculture is small and further weakened by urbanization. The computed structural development points to efficiency improvements specific to sectors to return the economy to balanced growth.     

中国大气汞排放变化的社会经济影响因素

基于投入产出模型,从生产和最终需求角度计算了1997~2017年中国大气汞排放量;并结合结构分解分析方法,定量分析了各种社会经济因素对大气汞排放变化的相对贡献.结果表明：生产端大气汞排放较多的行业主要是水泥、石灰和石膏制造业（135t）、有色金属冶炼及压延加工业（86t）等重工业;消费端对大气汞排放贡献较多的行业主要是建筑业（219t）、汽车制造业（16t）等.各种社会经济因素对不同排放源和不同行业的相对贡献存在差异.人均最终需求水平提高是大气汞排放增加的最大驱动因素,其中,有色金属冶炼及压延加工业,电力、热力的生产和供应业,水泥、石灰和石膏制造业是其推动排放增加的主要行业.排放强度降低是大气汞排放减少的最大驱动因素,对有色金属冶炼及压延加工业,电力、热力的生产和供应业,水泥、石灰和石膏制造业的减排贡献最大.生产结构、最终需求行业结构和最终需求类别结构变化导致大气汞排放略有增加,但1997~2017年间因这3种结构性因素变化而减少汞排放的排放源和行业数量增多.根据研究结果,本文从生产全过程管控、优化社会经济结构等角度提出相关政策建议.     

基于描述函数法的典型结构非线性识别方法研究

目的为典型的结构非线性提供识别方法。方法基于动力学基本理论,对典型结构非线性系统在建模时,将非线性单元产生的非线性力作为位移或速度的函数加入到潜在的线性系统中,对不同激励量级的频响函数加以分析,通过描述函数法识别非线性单元的位置、类型和参数。结果通过Matlab编程进行仿真验证,使用描述函数法对非线性系统进行识别,成功对三种不同情况的非线性系统实现了非线性单元识别。结论描述函数法识别的非线性位置是准确的,类型是匹配的,参数准确度极高。     

中国粮食作物种植结构调整及其水土资源利用效应

粮食种植结构调整会影响农业资源的消耗需求。20世纪90年代中后期以来,玉米在我国粮食生产中的地位明显提升。以粮食种植结构无调整为参照情景,一定产量下,1996-2015年,在国家层面,因粮食种植结构调整对水土资源消耗的节省量约占现期需求量的4%左右。在区域层面,从结构调整对种植面积的减省效应看,耕地资源相对丰富的北方地区明显高于南方地区;从对水资源消耗的减省效应看,北方贫水区也普遍高于南方地区,干旱度最高的西北地区最高。期间区域分品种粮食生产广泛受到作物种植比例变化的影响。研究结果表明,要充分利用好南方水热资源,恢复水稻生产,主要取决于稻米需求及其种植效益,而北方地区则要尽可能按降水规律调整农作制度,合理控制水稻、小麦的种植面积。