严寒地区高速铁路混凝土基床聚氨酯保温特性试验研究

基于严寒区京沈客专朝阳试验段路基基床的温度监测资料分析,研究不同厚度聚氨酯保温板对高速铁路路基混凝土基床温度变化特性影响.测试结果表明:①铺设聚氨酯保温板能够有效阻断严寒区环境与路基基床间的热量传递,保温效果与板厚相关;②地温大多数时间呈阳高阴低现象,同时阴、阳坡路基温差波动幅度随埋深逐渐减小;③基床表层阴、阳面各测点的温度变化起始时间一致,而阴面的冻结时间比阳面晚一个月.由此表明,保温板能够有效降低环境与混凝土道床之间的热交换,但是对路基阴、阳坡的影响存在差异.建议在严寒地区高速铁路路基阳、阴坡可以采取不同厚度的聚氨酯保温板,减小阴阳坡地温差异,保持季冻土路基温度变化稳定.     

当代中国城镇化的问题及提升策略

改革开放让中国城镇化水平明显提高,已经达到中等收入国家的平均水平,但仍存在需要提升之处:城镇化动力的非经济性因素占比较大,需要强化市场机制的主导作用;城乡矛盾依旧存在,需要进一步推动城乡融合;城镇化进程存在不协调因素,需要进一步促进城镇化的和谐进行.政府需要提升城市规划的科学性,促进城市基础设施水平和功能持续加强,引导制度革新,通过制定公平的政策来协调各方利益,消除阻碍市场体制建设的障碍,建立开放、自由的市场意识,提高公共服务水平.     

普惠金融发展的地区差异、收敛性及影响因素研究*——基于中国省级面板数据的检验

本文利用2005—2016年省级面板数据，对我国各地区普惠金融发展水平进行测度，并在此基础上探讨其收敛性及影响因素。结果表明：（1）我国普惠金融发展水平在考察期内总体偏低，并且呈现出显著的地区差异性。（2）绝对β收敛在全国、中部和西部均存在，而东部不存在；条件β收敛在全国、东部和西部均存在，而中部不存在。（3）政府干预程度、市场化程度、人力资本质量、非正规金融以及外商直接投资对普惠金融发展均具有重要的影响。     

The heterogeneous relationship between board social ties and corporate environmental responsibility in an emerging economy

Firms in emerging economies are faced with multiple, incompatible institutional forces in their environmental activities. Which of these forces will be dominant and instantiated within an organization is partly determined by the social relationships that a firm maintains with external actors. This paper investigates the relationship between board social ties and the level of environmental responsibility undertaken by firms in China, an emerging economy, by categorizing board social ties into three types in terms of the three isomorphic forces in the institutional field (coercive, normative and mimetic). Drawing on institutional and agency theories, using a sample of listed firms in environmentally sensitive industries, and a generalized least squares regression method, the results provide empirical evidence that ties that are linked to coercive and normative forces (i.e., political organizations and universities) are related to a higher level of environmental responsibility; however, those that are linked to mimetic forces (i.e., industrial peers) have a negative association with environmental responsibility, which is mitigated by CEO power. These findings suggest that the heterogeneous effects of board social ties on environmental responsibilities experienced by firms in a context of environmentalism are at an early stage.     

Factor Heterogeneity,Factor Market Imperfection and Trade

This paper develops a tractable model of examining how factor heterogeneity and imperfect factor market interact for determining a pattern of trade. Institution plays a crucial role for the interaction. In my work, firm productivity is defined as a composition of factor productivity and technology. Thus, input selection should affect the pattern of Melitz’s intra-industry allocation due to the incurring transaction cost. For a simple model, I assume two factors (labor and capital) and two sectors, which are relatively less institution-dependent and relatively more institution-dependent. When the economy is open, effect of the transaction cost on income distribution is more drastic for an institutionally underdeveloped country. Depending on institutional quality, the economic openness reallocates resource across countries through job creation or job destruction. The job turnovers redistribute income between heterogeneous labors within countries. The income redistribution is catalyzed by international mobility of capital. As a result, income disparity is widened between the institutionally developed country and the institutionally underdeveloped country. This paper can contribute to the literature of institution and international trade.     

基于动态冲击试验的通勤类飞机座椅符合性验证技术

国产某型民用通勤类飞机为了取得欧洲航空安全局(EASA)型号合格证,机上座椅需进行设计更改并补充进行应急着陆情况下的动态要求符合性验证.通过对适航条款及相应标准的解读,研究了基于动态试验的航空座椅动态要求适航验证技术,其主要包括座椅动态性能基本要求、试验构型及工况筛选、试验规划、合格判据和试验结果分析等内容.结果表明,该型机旅客座椅满足适航规章对座椅的动态性能要求.该项旅客座椅动态性能试验的成功为型号取得EASA型号合格证奠定了良好的基础,该型飞机也即将成为第一个取得欧洲型号合格证的国产飞机.     

增信服务还是腐蚀效应:论金融科技等新兴产业发展过程中的风险信号

提出行业性风险暴发的"腐蚀效应"理论,即存在着一种特殊的行业风险暴发过程:行业中各个企业的倒闭是沿着企业的资质链从低到高的顺序发生的.该过程的存在得到了数据回归证实.对于科技金融等新兴行业,警惕和积极防范腐蚀效应,对防范行业性风险具有重要意义.对于客户信任高度依赖的新兴行业,如金融科技等,最容易出现腐蚀效应.因此,在一度高速膨胀的网络贷款领域出现腐蚀效应具有一定必然性."腐蚀效应"的存在也否定了当前把网络贷款行业大面积爆雷的原因归咎于其开展"增信服务"的普遍观点,真正引发风险的原因是网络贷款行业中的企业资质参差不齐和无序竞争造成的无谓成本的大幅增加.从政府对行业的管理视角来看,在促进行业发展时不忘记防范风险十分重要.这在实质上是对制度-制度接口的设计问题.因此应当以制度设计理论来指导防范风险政策的制定,才能取得更好的效果.     

The effect of corporate real estate ownership on R&D innovation: credit relief vs. resource replacement in China

Against the background of supply-side structural reform and the real estate financialisation in China, this study investigates the impact of real estate holdings on R&D investment using data of enterprises listed on the Shanghai and Shenzhen stock exchanges. Our empirical results yield five main findings. First, enterprises holding more real estate assets face more serious financial constraints, thus restraining corporate innovation efficiency. Second, when the profit margin gap between entity enterprises and the real estate industry is larger, enterprises are more inclined to transfer industrial capital into the real estate industry, thus reducing R&D investment. Third, when the degree of marketisation is high, intensified market competition, the optimal allocation of factor and product markets, and stronger patent protection will weaken the restraining effect of corporate real estate holdings on R&D investment. Fourth, monopoly enterprises obtain potential profits more than undertaking risks from the real estate industry, they are more willing to hold real estate, thus strengthening the restraining effect of real estate holdings on innovation. Finally, investors' regional preference intensifies the restraining effect of corporate real estate holdings on R&D investment. Our empirical evidence can guide entity enterprises on how to effectively balance short-term (non-productive) and long-term (productive) capital investment.     

城镇群空间结构与要素集聚

依据城镇化发展过程中要素空间集聚理论，展开区域经济发展的空间经济结构研究。通过城市引力、克鲁格曼指数计算，比较分析城镇群内部城市吸引力和城市产业分布的差异性，通过人口与生产空间分布集中度指标和不一致系数的测算，分析了山西省城镇群空间要素集聚效应。研究表明，山西省的城镇群规划与要素空间集聚趋势整体一致，城市间产业分工体系基本形成，城镇群的要素集聚效应明显，但人口与生产分布仍存在不一致性。研究认为，山西省城镇群发展应该继续明确各城市的产业分工和特色，引导劳动力和资本要素的合理流动，实现人口与生产空间分布的一致。