我国GDS系统的发展现状及其对策分析

加入WTO后,我国航空领域中的信息、票务、服务等三大市场将逐渐放开,而国内航空和旅游业的信息技术和信息服务相对于发达国家还处在起步阶段,功能不健全,网络不发达,缺乏市场竞争力。如何从战略的高度尽快接受并引入新技术以完善中国的GDS系统,已变得十分迫切。     

Green cities? Urbanization,trade, and the environment

Is urbanization good for the environment? This paper establishes a simple core–periphery model with monocentric cities, which comprises key forces that shape the structure and interrelation of cities to study the impact of the urban evolution on the environment. We focus on global warming and the potential of unfettered market forces to economize on emissions. The model parameters are chosen to match the dichotomy between average “large” and “small” cities in the urban geography of the United States, and the sectoral greenhouse gas emissions recorded for the United States. Based on numerical analyzes we find that a forced switch to a system with equally sized cities reduces total emissions. Second, any city driver which pronounces the asymmetry between the core and the periphery drives up emissions in the total city system, too, and the endogenous adjustment of the urban system accounts for the bulk of the change in emissions. Third, none of the city drivers gives rise to an urban environmental Kuznets curve according to our numerical simulations. Finally, the welfare‐maximizing allocation tends to involve dispersion of cities and the more so the higher is the marginal damage from pollution.     

Does clean air increase the demand for the consumer city? Evidence from Beijing

Cities offer a large menu of possible employment and leisure opportunities. The gains from such consumer city leisure are likely to be lower on more polluted days. We study the association between daily consumption activity and outdoor air pollution in China and find evidence in favor of the hypothesis that clean air and leaving one's home for leisure trips are complements. Given the high levels of air pollution in cities in the developing world, regulation induced improvement in environmental quality is likely to further stimulate demand for the consumer city.     

Perceived Risk and Citizen Preferences for Governmental Management of Routine Hazards

Risk perceptions are important to the policy process because they inform individuals’ preferences for government management of hazards that affect personal safety, public health, or ecological conditions. Studies of risk in the policy process have often focused on explicating the determinants of risk perceptions for highly salient, high consequence hazards (e.g., nuclear energy). We argue that it is useful to also study more routinely experienced hazards; doing so shows the relevance of risk perceptions in individuals’ daily lives. Our investigation focuses on the impact perceived risk has on citizens’ preferences over hazard management policies (as distinct from identifying risk perception determinants per se). We use a recursive structural equation model to analyze public opinion data measuring attitudes in three distinct issue domains: air pollution, crime, and hazardous waste storage and disposal. We find that citizens utilize perceived risk rationally: greater perceived risk generally produces support for more proactive government to manage potential hazards. This perceived risk–policy response relationship generally holds even though the policy options respondents were asked to consider entailed nontrivial costs to the public. The exception seems to be when individuals know less about the substantive issue domain.     

中国城市密集区航空运输联系研究

城市密集区间的航空运输联系导致城市间的内聚效应和空间互动。城市密集区间的航空运输联系具有明显方向性。京津唐、长江三角洲和珠江三角洲城市密集区间航空运输联系密切,国家级大都市与国家级大都市(区域性大都市)间联系具有普遍性,而与地方性城市中心间航空运输联系具有特殊性。长江三角洲、珠江三角洲和京津唐城市密集区等为人流与信息流联系密切的、以辐射为主的航空中心;辽宁中南部城市密集区为航空运输联系欠密切的、人流辐射与信息流集聚中心;四川盆地城市密集区为航空运输联系欠密切的、人流集聚与信息流辐射中心。     

博物馆文物环境用甲醛净化材料评价方法研究

博物馆文物环境因装饰材料所致甲醛污染以及由此产生对文物危害问题已被普遍关注.为了评价净化材料实际使用中对污染物去除净化能力,搭建了静态试验舱,建立了该环境中甲醛的定量分析方法.研究了甲醛溶液法和人造板散发法两种产生甲醛气体的方法,以及吸附材料不同加入方法等对净化材料评价结果的影响,研究试验舱内甲醛浓度随时间的变化规律,建立了净化材料脱附量检测方法,分别测定了活性炭和三种壳聚糖基净化材料的净化效果.结果表明,用人造板散发法产生甲醛气体方法能用于甲醛净化材料的评价,得到净化率指标反映了净化材料在实际文物环境中的应用效果,脱附量指标能直观比对和反映净化材料对污染物的吸附稳定性.