渚滑川河口拦门沙演变特性

河口拦门沙的存在可导致径流流出不畅，并能引起一系列的河口生态及环境问题。特别是弯曲型河口，在波浪流、河川径流及弯道副流的共同作用下，拦门沙的形成及演变将更为复杂。通过对日本渚滑川河口多次实地调查资料的分析，揭示了渚滑川河口拦门沙的演变特性。结果表明：渚滑川河口修筑防波堤后，在东北方向的海洋入射波作用下，拦门沙由河口右岸发育并向左岸逐渐延伸扩展，其河水流动也相应由右岸偏向左岸一侧；不论河口有无拦门沙，3次洪水在右岸的最大冲深均稳定在-6m高程，且河床横剖面的形状基本不变，即汛期时该河口河床形状已达平衡状态。     

雾灵山自然保护区的生态效应与保护对策

通过对雾灵山国家级自然保护区的调查，研究保护区的生态沿革，分析保护区的生态功能、生态作用等生态效应，针对当前所存在的草甸严重退化、动物种群密度降低、水量减少等生态问题，提出对保护区的生态环境应尽快制定环境保护规范化，建立生物多样性保护权威机构，实行社区共管，开展科学生态旅游等措施。     

Combining geodiversity with climate and topography to account for threatened species richness

Understanding threatened species diversity is important for long‐term conservation planning. Geodiversity—the diversity of Earth surface materials, forms, and processes—may be a useful biodiversity surrogate for conservation and have conservation value itself. Geodiversity and species richness relationships have been demonstrated; establishing whether geodiversity relates to threatened species’ diversity and distribution pattern is a logical next step for conservation. We used 4 geodiversity variables (rock‐type and soil‐type richness, geomorphological diversity, and hydrological feature diversity) and 4 climatic and topographic variables to model threatened species diversity across 31 of Finland's national parks. We also analyzed rarity‐weighted richness (a measure of site complementarity) of threatened vascular plants, fungi, bryophytes, and all species combined. Our 1‐km² resolution data set included 271 threatened species from 16 major taxa. We modeled threatened species richness (raw and rarity weighted) with boosted regression trees. Climatic variables, especially the annual temperature sum above 5 °C, dominated our models, which is consistent with the critical role of temperature in this boreal environment. Geodiversity added significant explanatory power. High geodiversity values were consistently associated with high threatened species richness across taxa. The combined effect of geodiversity variables was even more pronounced in the rarity‐weighted richness analyses (except for fungi) than in those for species richness. Geodiversity measures correlated most strongly with species richness (raw and rarity weighted) of threatened vascular plants and bryophytes and were weakest for molluscs, lichens, and mammals. Although simple measures of topography improve biodiversity modeling, our results suggest that geodiversity data relating to geology, landforms, and hydrology are also worth including. This reinforces recent arguments that conserving nature's stage is an important principle in conservation.     

SRHSC梁主要设计参数损伤敏感度分析

以型钢高强混凝土(SRHSC)梁为研究对象,结合SRHSC梁受力机理及承载能力的试验研究成果,提出了极限状态下的承载能力是评价梁力学性能的关键指标,将损伤前后梁正截面抗弯承载力之比和斜截面抗剪承载力之比的均值作为自变量,给出了SRHSC梁损伤表征函数,并借助"预定损伤法",揭示了主要设计参数对SRHSC梁损伤演化的影响规律。研究成果将为建立地震激励下SRHSC框架结构楼层损伤模型提供理论和数据支持。     

突发事件情景演化及关键要素提取方法

针对突发事件应急处置难度大的特点,突发事件应急管理模式必须向"情景-应对"转变。从系统复杂性、开放式预先设想以及序贯性三个主要原则的角度理解突发事件情景演化的机理,构建了突发事件情景演化系统模型,并以此为基础设计了突发事件情景网络关键要素的提取方法。该方法以危险源形成、突发事件演化以及应急响应三方面主要内容为情景网络的主体,以三方面主要内容所涉及的影响因素为分支,适当的选取情景网络关键要素并将关键要素分为四类。该方法的提出弥补了情景网络关键要素提取方法理论的空白,为突发事件情景构建提供了理论支持。     

基于情景信息扩散模型的雾霾社会风险演化仿真研究

雾霾灾害不仅危害公众健康,且风险信息的传播会引发社会次级风险。为了研究社会风险信息的扩散演化趋势,本文构建了雾霾社会风险的情景信息扩散模型。以中国2013年雾霾灾害为例,将风险信息扩散过程分为爆发期、扩散期和稳定期,分析了不同参数条件下的信息扩散规律。结果表明,政府应在风险信息爆发期和扩散期增大官方渠道信息的覆盖范围,尤其在爆发期需对自由渠道发布的信息进行严格监管,在社会风险扩大之前制定应对策略。     

An integrated EDIB model for probabilistic risk analysis of natural gas pipeline leakage accidents

Natural gas pipeline construction is developing rapidly worldwide to meet the needs of international and domestic energy transportation. Meanwhile, leakage accidents occur to natural gas pipelines frequently due to mechanical failure, personal operation errors, etc., and induce huge economic property loss, environmental damages, and even casualties. However, few models have been developed to describe the evolution process of natural gas pipeline leakage accidents (NGPLA) and assess their corresponding consequences and influencing factors quantitatively. Therefore, this study aims to propose a comprehensive risk analysis model, named EDIB (ET-DEMATEL-ISM-BN) model, which can be employed to analyze the accident evolution process of NGPLA and conduct probabilistic risk assessments of NGPLA with the consideration of multiple influencing factors. In the proposed integrated model, event tree analysis (ET) is employed to analyze the evolution process of NGPLA before the influencing factors of accident evolution can be identified with the help of accident reports. Then, the combination of DEMATEL (Decision-making Trial and Evaluation Laboratory) and ISM (Interpretative Structural Modeling) is used to determine the relationship among accident evolution events of NGPLA and obtain a hierarchical network, which can be employed to support the construction of a Bayesian network (BN) model. The prior conditional probabilities of the BN model were determined based on the data analysis of 773 accident reports or expert judgment with the help of the Dempster-Shafer evidence theory. Finally, the developed BN model was used to conduct accident evolution scenario analysis and influencing factor sensitivity analysis with respect to secondary accidents (fire, vapor cloud explosion, and asphyxia or poisoning). The results show that ignition is the most critical influencing factor leading to secondary accidents. The occurrence time and occurrence location of NGPLA mainly affect the efficiency of emergency response and further influence the accident consequence. Meanwhile, the weight ranking of economic loss, environmental influence, and casualties on social influence is determined with respect to NGPLAs.     

Graduated driver licensing: the New Zealand experience

In New Zealand, on 1 August 1987, a three-stage graduated driver licensing (GDL) system that applied to all new drivers aged 15-24 years was introduced. The essential elements of GDL were a 6-month learner license (supervised driving) and an 18-month restricted license stage (with restrictions on night driving and carrying passengers). A blood alcohol limit of 0.03 mg% applied at both stages. EVALUATION STUDIES: Early studies indicated that young people were reasonably accepting of the restrictions, with the passenger restriction being the least acceptable. Problems of compliance with the restricted license driving restrictions were reported. Evaluations of the impact of the graduated driver licensing (GDL) on serious traffic-related injury showed that up until 1991-1992, an 8% reduction could be attributed to GDL. At this time, it was considered that reduced exposure was the main reason for this reduction. However, the number of fatalities and hospital admissions among young people continued to decline, as did the population rate and the rate per number of licensed drivers among the young driver age group. A further evaluation study showed that drivers with a restricted license had a smaller proportion of crashes at night, and with passengers, compared with drivers licensed before GDL. IMPACT OF GDL: These results suggested that GDL restrictions had contributed to the reduction in crashes among young people and that it was not simply a case of reduced exposure to risk. An update of the most recent crash statistics indicated that, compared with older age groups, the fatal and serious injury crash rate among young people has remained substantially below the pre-GDL level. This suggests that the impact of GDL has not diminished over time.     

乡村人居环境系统韧性的演变规律及其提升路径——以国家城乡融合发展试验区重庆西部片区为例

以国家城乡融合发展试验区——重庆西部片区为研究区,以2009年、2014年、2019年为研究时点,以2009—2019年为研究时段,按照思想缘起、理论基础、实证演绎、提升路径的研究思路,建立乡村人居环境系统韧性测度的指标体系,分析其演变规律。研究结果表明：2009—2019年,重庆西部片区的乡村人居环境系统韧性水平不断上升,呈现出“南高北低”的空间格局。各子系统韧性在时间上呈现出不同程度的增长趋势,在空间上差异明显：自然系统韧性与人类系统韧性分别呈现出“由南向北递减”和“东西部向中部递减”的空间格局;居住系统韧性与支撑系统韧性则分别呈现出由“低值点缀分布”逐渐过渡到较为均衡和“普遍均衡、高低值点缀”的空间格局;社会系统韧性表现为“西部增强、东部减弱”的空间格局特征。借助障碍度模型对重庆西部片区乡村人居环境系统韧性提升的障碍因子及不同区县面临的主导障碍进行诊断,根据结果将重庆西部片区划分为单一主导障碍型、双重障碍型与三层障碍型三种类型,据此设计乡村人居环境系统韧性提升的差异化路径,以期打破重庆西部片区乡村人居环境系统韧性提升的多重制约。     

中国旅游业绿色发展效率时空演变特征及影响机理

绿色发展是旅游业可持续发展理念的重要组成部分,是旅游业奉行以人为本、生态至上和全面发展的新价值观。在梳理旅游业绿色发展概念及内涵基础上,构建旅游业绿色发展效率评价体系,运用SBM-Undersirable模型、核密度估计、空间马尔科夫链等方法,探讨2008—2018年中国31个省（市、自治区）旅游业绿色发展效率（TGDE）时空演化特征及影响机理。研究发现：（1）时间和空间变化方面,TGDE总体处于中等偏下水平,时间上呈“W”型变化形态,“下降—上升—调整”阶段特征显著;空间呈“东—中—西”递减分布,内部差异为西部地区>东部地区>中部地区,低、中、高效率由“金字塔”向“菱形”结构转变,高效率地区集中于东部沿海,中等效率多分布于中西部地区,低效率位于胡焕庸线两侧。（2）动态演进方面,TGDE始终存在两极分化现象,但区域协调性逐步增强,具有较强平稳性,难以实现跨越式发展,空间向上转移省份比较集中,以中西部为主,向下调整省份较少,且存在明显的空间溢出效应,溢出影响具有不对称性。（3）影响机理方面,总体上,经济水平、产业结构、政府规制、教育水平和旅游资源影响因子与TGDE间存在显著的正向关系,对外开放程度的作用不显著,但各因子的影响程度、作用机理及条件具有较强地域性。