交通基础设施与民族地区高质量发展——来自高铁开通的证据

交通基础设施的持续完善,是我国民族地区实现高质量发展的重要基础支撑。以高铁开通作为民族地区交通基础设施改善的准自然实验,结合2004~2018年民族八省区地级城市的经济社会发展数据,采用渐进性双重差分模型,实证检验了交通基础设施对我国民族地区高质量发展的影响,结果显示:民族地区的高铁建设具有选择性,高铁发展阶段、城市规模、以及与规划骨干网的距离均有可能影响所在城市的高铁开通;整体来看,高铁开通对民族地区的高质量发展具有积极影响,且高铁的影响既表现出显著的“节点效应”,又展现了较强的“场所效应”;从影响的异质性看,高铁规模和新建站点对高质量发展的影响会分别随城市财政实力的增强和人口密度的增加而增大,体现出影响的“马太效应”;从影响的动态性看,在高铁开通的第三年,其对城市高质量发展的影响开始变得显著,至第五年累积影响则达到最大,其后快速衰减,显示出高铁影响高质量发展的时滞性和阶段性;从影响的机制看,高铁开通可通过交通改善机制和投资激发机制促进民族地区的高质量发展,且当前投资激发机制所具有的中介作用更大;基于有效挖掘“高铁红利”考量,研究结果蕴含的政策含义包括:进一步加强民族地区的高铁建设;完善高铁站点周边的配套基础设施建设;增强高铁配套设施建设资金的保障力度。     

Make way for the wealthy? Autonomous vehicles,markets in mobility,and social justice

ABSTRACT

The development of a ‘mobility as a service’ model for accessing urban transport via autonomous vehicles may be expected to have far-reaching implications for the economics of road transport. In particular, it would offer a new opportunity to price access to the roads in accordance with the principles of the free market. Once people are paying for mobility on the roads on a ‘per trip’ basis, it will be possible to offer different levels of access – and service – at different prices. According to hegemonic ideas in the transport planning and economics literature the introduction of such a ‘market in mobility’ would be an economically efficient way of allocating access to the scarce good of space on the roads. In this paper we draw attention to a number of ethical and political challenges to the appropriateness of the use of such a pricing mechanism in the context of urban mobility.     

杂化膜驻极体PVDF／SiO_2的电荷输运特性

通过常温和高温下对ＰＶＤＦ／ＳｉＯ＿２，（ＰＶＤＦ－聚偏氯乙烯）膜的恒压负电晕充电，系统地研究了充电注入的负表面电荷受激脱阱后在电荷层自身内场作用下的输运规律。确定了ＴＳＤ（ＴｈｅｒｍａｌｌｙＳｔｉｍｕｌａｒｅｄＤｉｓｃｈａｒｇｅ）的偶极峰和空间电荷峰对电荷稳定性的明显区另。实验结果表明，高温负电晕充电对该材料的驻极性能有明显的改善。     

碱水驱组分输运过程有效性研究

建立了碱水驱组分孔隙输运数学模型,将模型中所需的物化参数描述为驱油剂浓度相关的函数,用“有效驱替带”量化和分析了吸附、驱油剂段塞尺寸、驱替速度、扩散弥散等因素对碱组分输运过程有效性的影响机理。在此基础上,进一步分析了大庆油田ASP复合驱用碱剂NaOH在孔隙输运过程中的有效性和持久性,并对模拟软件进行了实验验证,它们具有很好的一致性。经过实验验证的模拟软件,不仅可代替部分实验室流动实验和辅助机理分析,而且可以为碱水驱和ASP复合驱工程工艺方案设计和动态监测提供指导。     

基于ARM9的无线数据传输终端的设计

设计了1个基于ARM9与GPRS模块的工程机械无线数据传输终端。该终端以samsung公司的s3c2440a微处理器为控制核心，利用BenQ M22模块进行GPRS无线传输，克服了工业、军事等领域一些设备工作环境受地域限制数据传输不便的问题。实现实时监控，为机械设备故障诊断与维修提供了依据。     

Stochastic Estimates of Exposure and Cancer Risk from Carbon Tetrachloride Released to the Air from the Rocky Flats Plant

Carbon tetrachloride is a degreasing agent that was used at the Rocky Flats Plant (RFP) in Colorado to clean product components and equipment. The chemical is considered a volatile organic compound and a probable human carcinogen. During the time the plant operated (1953-1989), most of the carbon tetrachloride was released to the atmosphere through building exhaust ducts. A smaller amount was released to the air via evaporation from open-air burn pits and ground-surface discharge points. Airborne releases from the plant were conservatively estimated to be equivalent to the amount of carbon tetrachloride consumed annually by the plant, which was estimated to be between 3.6 and 180 Mg per year. This assumption was supported by calculations that showed that most of the carbon tetrachloride discharged to the ground surface would subsequently be released to the atmosphere. Atmospheric transport of carbon tetrachloride from the plant to the surrounding community was estimated using a Gaussian Puff dispersion model (RATCHET). Time-integrated concentrations were estimated for nine hypothetical but realistic exposure scenarios that considered variation in lifestyle, location, age, and gender. Uncertainty distributions were developed for cancer slope factors and atmospheric dispersion factors. These uncertainties were propagated through to the final risk estimate using Monte Carlo techniques. The geometric mean risk estimates varied from 5.2 x 10(-6) for a hypothetical rancher or laborer working near the RFP to 3.4 x 10(-9) for an infant scenario. The distribution of incremental lifetime cancer incidence risk for the hypothetical rancher was between 1.3 x 10(-6) (5% value) and 2.1 x 10(-5) (95% value). These estimates are similar to or exceed estimated cancer risks posed by releases of radionuclides from the site.     

宋代江西地区交通建设与维护述论

江西地区自古即有水陆交通之便,宋代水陆交通进一步拓展,新建了多条驿道,加强了对道路的整修与维护,极大地改善了本区的内外交通条件,有力地促进了江西社会经济的发展,收到了良好的社会效果。     

主副拱协作体系柔性系杆拱桥拱肋刚度优化

在回顾和分析铁路改革进程的基础上，提出解放运输生产力，提高运输效率是铁路改革目的，“政企分开”是改革目标和手段的观点。铁路改革必须解放思想，开拓思路，保持运输高效率，且须臾不可偏离改革目的。     

略论三国后期的两淮水利工程

汉末世乱,社会经济遭到严重破坏,曹操为强兵足食而推行屯田措施,从而刺激了曹魏时期水利工程的建设。曹魏的农田灌溉水利工程为曹魏经济的恢复和发展奠定了坚实的物质基础;军事漕运水利工程的兴修为曹魏、西晋的伐吴提供了保证。曹魏的两淮水利工程对三国后期政治格局的变动产生了重要的影响。     

Stuck in the Slow Lane: Reconceptualizing the Links between Gender,Transport and Employment

This article draws on primary research undertaken in the North East of England to explore the way in which inequalities in access to transport resources impact on women’s opportunities to enter the public domain of paid work. It advances the idea of spatiality as a social construction and, building on previous studies, it explores the way in which a gender division of transport operating in the home and at work limits women’s access to temporal, financial and personal and geographic travel resources; ultimately constraining women’s mobility and restricting their employment opportunities. Finally, the article will argue that, although some women can achieve ‘masculine’ levels of transport resources, the majority of women are stuck in the slow lane and their mobility deprivation often confines them to the private world of the family, or alternatively, to part‐time, low paid work on the periphery of the labour market. This leads to the conclusion that there is an urgent need to provide women with a range of mobility choices which enhance their access to the labour market and to challenge the socially constructed processes which underpin the discrimination women face when accessing the world of paid employment.