不同生态修复模式下土壤水文性质及其对溶质运移的影响

煤矿区生态修复过程中不可避免地改变了土壤水和溶质运移过程.土壤水是溶质运移的主要载体,溶质运移受土壤水文性质与植被状况影响.以我国北方典型半干旱区山西古交矿区草本、灌草和乔灌草3种不同生态修复区和撂荒地的土壤为研究对象,揭示不同生态修复模式下土壤水文性质变化规律及其对溶质运移的影响.结果表明,土壤持水性从大到小依次为乔灌草地灌草地草地撂荒地,草本、灌草和乔灌草3种植被修复区的土壤持水量相对于撂荒地分别增加了33.79%、59.19%和62.71%,植被修复有助于增加土壤层蓄水能力.土壤饱和导水率由大到小依次为草地(1.736 mm·min~(-1))灌草地(1.678 mm·min~(-1))乔灌草地(1.564 mm·min~(-1))撂荒地(1.012 mm·min~(-1)),非饱和导水率随吸力增大而呈指数下降,植被修复过程中降低容重的同时提高了土壤持水性,改善土壤持水性能.不同生态修复区土壤中溶质穿透时间呈草地灌草地乔灌草地撂荒地的趋势.CDE、SC和TRM模型均可对矿区不同生态修复模式土壤的溶质运移过程进行较好的表达,其中CDE模型拟合效果最好.结果表明研究区溶质运移方式以对流为主,而且土壤容重和砂粒含量是影响溶质运移的主要因素.     

城市生命线系统安全保障对策探析

针对我国城市生命线系统存在的抗灾能力弱、缺乏综合规划、缺乏相应的统筹应急体制和生命线系统安全保障的科技水平总体较低等诸多问题,提出城市生命线系统的安全应从注重规划、更新传统模式、加大基础设施投入和提高管理水平、完善应急体制等多种途径加以保障,构建完善的城市生命线系统安全保障体系,以提高我国城市整体安全性能和抗灾能力,从而实现城市安全和城市化同步发展。     

Differential use of conspecific-derived information by sexual and asexual parasitic wasps exploiting partially depleted host patches

When foraging partially depleted patches (i.e., a fraction of hosts are already parasitized), female parasitoids must decide: 1—whether to superparasitize, and 2—whether to stay in their current patch (thus missing the opportunity of finding a better patch elsewhere). To make these decisions, parasitoids may rely on different cues, produced both by the environment and by conspecifics. Animals thriving in different environments may differ in cues they use. In the solitary parasitoid Venturia canescens, thelytokous (asexual) and arrhenotokous (sexual) individuals are found in two contrasting environments. Thelytokous females, from anthropogenic conditions, are known to cope with superparasitism in an adaptive way. On the other hand, little is known about superparasitism by arrhenotokous females. We compared the host exploitation strategies of thelytokous and arrhenotokous females in partially depleted patches. Hosts parasitized by thelytokous females were more frequently avoided than those parasitized by arrhenotokous females, suggesting a stronger chemical marking of the former. Only thelytokous females used information from conspecifics for patch-leaving decisions. The conformity of the differences in the behavior of thelytokous and arrhenotokous females with the environmental conditions they experience in their habitat is discussed.     

堆肥系统的通风控制方式

对堆肥系统的不同通风控制方式比较结果表明,强制通风静态垛系统宜采用通风速率变化的时间－温度反馈正压通风控制方式（控制堆体中心最高温度为６０℃）,密闭式堆肥系统宜采用Ｏ₂含量反馈的通风控制方式（保持堆料间Ｏ₂ 体积分数为１５％ ～２０％）． 在中国,堆肥系统采用时间控制和时间－温度反馈控制的通风方式比较经济和适宜．     

上海市居民出行方式与城市交通CO2排放及减排对策

以上海市居民出行方式为研究对象,利用联合国政府间气候变化专门委员会(IPCC)温室气体排放计算指南中关于交通能源消费碳排放量的计算方法,探讨2002—2006年上海市居民出行选择的不同交通方式对CO₂排放的影响和规律,并提供应对策略.结果表明,2002年以来上海市因居民出行导致的交通CO₂排放总量呈显著增长趋势.私家车的CO₂排放量增加速度最快,截至2006年私家车CO₂排放量约相当于出租车、轨道交通和公交车3种公共交通方式之和.公共交通中,出租车的CO₂年排放量和人均CO₂排放量都最大,轨道交通的CO₂年排放量和人均CO₂排放量最小.公交车和出租车的CO₂排放量所占比例减少,轨道交通的CO₂排放量所占比例增加,这种排放结构的变化有利于减少CO₂排放总量.CO₂减排的具体措施包括限制私家车数量,设计合理的道路交通方案,使汽车尽可能接近其经济车速,改变汽车燃料种类等,其中限制私家车数量最为关键.      

Commuter exposure to BTEX in public transportation modes in Bangkok, Thailand

Measurements and monitoring of volatile organic compounds (VOCs) have been conducted in the metropolitan Bangkok. However, in-vehicle levels of VOCs are still lacking. This study investigated VOCs concentrations in four public transportation modes in Bangkok, Thailand during two rush hour periods (7:00-9:00 a.m. and 4:00-7:00 p.m.). The four modes included an air-conditioned bus (A/C bus), non-air-conditioned bus (non-A/C bus), electric sky train, and a passenger boat traveling along the canal. Comparison among three important bus routes was also studied. In-vehicle air samples were collected using charcoal sorbent tubes and then analyzed by a gas chromatography-mass spectrometer. Results showed that the transportation modes significantly influenced the abundance of in-vehicle benzene, toluene, ethylbenzene, and m,p-xylene (BTEX). Median concentrations of BTEX were 11.7, 103, 11.7, and 42.8 μg/m3 in A/C bus; 37.1, 174, 14.7, and 55.4 μg/m3 in non-A/C bus; 2.0, 36.9, 0.5, and 0.5 μg/m3 in sky train; and 3.1, 58.5, 0.5, and 6.2 μg/m3 in boat, respectively. Wilcoxon rank sum test indicated that toluene and m,p-xylene in the sky trains were statistically lower than that in the other three modes at a p-value of 0.05. There were statistical differences in TEX concentrations among the bus routes in the non-A/C buses. In addition, the benzene to toluene ratios implied that tail-pipe emissions were important contributor to the abundance of in-vehicle VOCs.     

GEIA-STD-0009《系统设计、研制和制造可靠性大纲标准》分析

研究了GEIA-STD-0009《系统设计、研制和制造可靠性大纲标准》的制定背景,分析了该标准的制定过程,主要介绍了该标准4个可靠性目标及信息流,简述了每个目标的6个组成部分,详细阐述了13项规范性可靠性活动.     

On-road pollutant emission and fuel consumption characteristics of buses in Beijing

On-road emission and fuel consumption (FC) levels for Euro III and IV buses fueled on diesel and compressed natural gas (CNG) were compared, and emission and FC characteristics of buses were analyzed based on approximately 28,700 groups of instantaneous data obtained in Beijing using a portable emissions measurement system (PEMS). The experimental results revealed that NOx and PM emissions from CNG buses were decreased by 72.0% and 82.3% respectively, compared with Euro IV diesel buses. Similarly, these emissions were reduced by 75.2% and 96.3% respectively, compared with Euro III diesel buses. In addition, CO2, CO, HC, NOx, PM emissions and FC of Euro IV diesel buses were reduced by 26.4%, 75.2%, 73.6%, 11.4%, 79.1%, and 26.0%, respectively, relative to Euro III diesel buses. The CO2, CO, HC, NOx, PM emissions and FC factors all decreased with bus speed increased, while increased as bus acceleration increased. At the same time, the emission/FC rates as well as the emission/FC factors exhibited a strong positive correlation with the vehicle specific power (VSP). They all were the lowest when VSP < 0, and then rapidly increased as VSP increased. Furthermore, both the emission/FC rates and emission/FC factors were the highest at accelerations, higher at cruise speeds, and the lowest at decelerations for non-idling buses. These results can provide a base reference to further estimate bus emission and FC inventories in Beijing.     

基于资源比较优势的森林公园旅游增长方式合理性研究

利用Cobb-Douglas函数对各省森林公园旅游增长方式进行判别,结合“资源比较优势”和“资源利用合理度”,重点分析旅游资源在森林公园旅游增长过程中的作用及其利用水平。研究发现：中国森林公园在旅游增长过程中,不仅存在资本投入过剩现象,也存在旅游资源利用不合理的现象,并且由于资本投入过剩直接导致部分省份的旅游资源处于不合理利用状态,表现为旅游资源“利用过度”和“利用不足”;全国有19个省份的旅游资源利用状态处于不合理状态,其中8个处于过度开发状态,以东部沿海和中部省份为主;11个处于利用不足状态,以西南和西北各省为主。旅游资源禀赋、旅游资源比较优势和旅游资源利用合理度会因各省资本投入的不同而出现不完全匹配的发展局面。     

基于摩拜骑行数据的上海市共享单车减排效益时空分析

移动互联网环境下的共享单车能够有效减少机动化出行,可在一定成程度上缓解当下交通污染、气候变化等问题,具有显著的减排效益.本研究基于上海市摩拜单车的骑行数据,结合精细化的交通方式排放因子及共享单车替代率调查数据,计算共享单车与其替代交通方式相比所减少的温室气体排放和污染物排放,并分析共享单车减排效益的时空分布特征.结果表明：2016年上海市共享单车的CO₂、CO、HC、NO_x、PM_2.5和PM₁₀减排量分别为6322、74、8.57、6.33、0.32、0.48 t;在时间上具有典型的峰谷现象,其中,早晚高峰贡献了约45%的减排量;在空间上主要分布于中心城区,其中,南京东路街道单位面积减排量最高.因此,上海市共享单车的减排效益主要产生于早晚通勤交通与人口集聚的地区.为了提高共享单车的减排效益,政府和运营者需要在未来继续扩大共享单车的覆盖范围,增加在郊区的投放数量,鼓励更多外围居民使用共享单车.