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581.
以合肥市的景观水体为研究对象,从景观水资源的自然属性和美学属性研究入手,探讨了城市水体的景观、环境和经济效应及美学特征,并在此基础上,应用"专家评估"与"系统调查分析"相结合的评价方法,对主要景观水体的美景度进行了综合评价。结果表明:合肥市内水景中美感度最高的是黑池坝风景区(113.3),其次是银河公园风景区(60.9),再次是雨花塘风景区(46.4),而美景度较差的是杏花公园(-27.5)和南淝河(-4.9)。  相似文献   
582.
塔里木河流域生态脆弱性评价研究   总被引:49,自引:1,他引:48  
塔里木河流域受自然及人为因素的影响,局部地区生态退化问题突出,从景观生态学的干扰性质理论和恢复生态学的观点出发,选择水资源系统、土地资源系统及植被资源系统及其10个综合性敏感因子对流域生态的敏感性及恢复力进行分析,并确定敏感因子的定量指标,定性代码及其权重和阈值,通过算术对数插值对敏感因子实际值进行规范化处理,并构建生态胁迫度。结果表明,塔里木河三源流阿克苏河流域、叶尔羌河流域、和田河流域及于流区的上、中、下游区生态胁迫度分别为0.13、0.25、0.30、0.31、0.57及0.84,在评价分级标准的限定下,其对应的生态脆弱性程度依次为轻微脆弱、一般脆弱、一般脆弱、一般脆弱、中等脆弱及严重脆弱。  相似文献   
583.
为缓解夏季配戴安全帽导致的头部高温不适,采用具有光谱选择特性的辐射降温涂料对安全帽表面光学性能进行改性,经光学测试,安全帽的太阳辐射反射率由45%提升至89%,大气窗口发射率由92%提升至95%。对安全帽进行降温效果测试,并基于测试结果建立热力学模型。结果表明:在阳光直射下,改性安全帽内部温度低于普通白色安全帽,温差最大12.2 ℃;在热力学模型中,即使在夏季最热时间段(12∶00~14∶00),改性安全帽内部温度仍可比普通安全帽低8 ℃,预测平均评价值由普通安全帽的3.5降低至1.0,预测不满意百分比从100%降低至20%。  相似文献   
584.
为量化环境条件对消防服热舒适性能的影响,选取我国02式消防服,测量其在不同环境温度、湿度及风速条件下的热阻和湿阻并得出拟合公式;通过回归分析法分析环境条件对热阻和湿阻的影响,提出其对热阻和湿阻影响的数学模型。结果表明:风速对热阻和湿阻的影响较大,而环境温度和湿度对热阻及湿阻的影响较少;风速与整体热阻及整体湿阻呈负相关,而风速与固有热阻和固有湿阻呈正相关。该研究可为消防服热舒适性能测试及高性能防护装备研发提供理论指导。  相似文献   
585.
为揭示半填半挖黄土路基的变形规律及其影响因素,为高填方黄土路基稳定性的评估提供科学依据。以国道G310典型半填半挖黄土路基为例,运用Settle3D软件对不同工况条件下的黄土路基进行精确建模与系统分析。结果表明:自然条件下路基左右侧沉降量差别不大,而降雨条件下原状黄土侧的沉降大于压实黄土侧的沉降,土层交界处沉降差异显著;降雨条件下中心点的沉降曲线在原填土交界处发生转折,表明压实效果显著;各施工阶段间沉降量差值呈非线性减小趋势,但降雨条件下的稳定时间更长。因此施工中控制路基压实度和采取合理的路基防水排水措施非常重要。  相似文献   
586.
• A hydrophilic resin (GCHM) was facile synthesis and characterized. • Average absolute recovery of GCHM (75.6%) performs better than Oasis® HLB. • Detection limits of method (SPE-UPLC-MS/MS) ranged between 0.03 and 0.6 ng/L. • 22 PPCPs were determined in environmental waters ranging from 0.5 to 1590 ng/L. In this study, a hydrophilic resin named GCHM was fabricated based on poly(N-vinyl pyrrolidone-co-divinylbenzene), characterized, and applied as a solid-phase extraction (SPE) material. Up to 44 pharmaceuticals and personal care products (PPCPs) belonging to 10 classes were recovered in environmental water samples. Different variables affecting extraction, such as adsorbent amount, sample pH, and loading speed, were optimized. Under optimal conditions, the average absolute recovery of 44 PPCPs was 75.6% using GCHM, indicating a better performance than the commercial Oasis® HLB. SPE with home-made hydrophilic polymeric sorbent followed by ultra-performance liquid chromatography and tandem mass spectrometry was validated, and the method achieved good linearity (r2>0.991, for all analytes). In addition, the method detection limits of target compounds ranged from 0.03 to 0.6 ng/L. The developed method was applied to determine PPCPs in 10 environmental water samples taken from the Yangtze River, Huaihe River, and Taihu Lake, 1 groundwater sample from Changzhou in Jiangsu Province, 1 wastewater sample from Xiamen and 2 seawater samples from the Jiulong River in Fujian Province, China. In these samples, 22 compounds were determined at levels ranging from 0.5 to 1590 ng/L.  相似文献   
587.
我国水资源、能源、粮食消费量均居世界首位,如何保证水资源-能源-粮食之间的协调发展成为我国实现可持续发展急需解决的关键问题。基于耦合协调度模型测算2003—2015年我国省际水-能源-粮食耦合协调度,并结合ESDA方法和空间计量模型探讨水-能源-粮食耦合协调度的空间相关性及影响因素。结果表明:①我国省际水-能源-粮食子系统及综合评价指数水平较低,呈现上升态势,其空间分布格局与我国水-能源-粮食资源禀赋分布格局相一致。②我国省际水-能源-粮食耦合度已处于高水平,但我国省际水-能源-粮食耦合协调度水平较低,呈现出稳定上升态势,存在较大的提升空间;我国省际水-能源-粮食耦合协调度具有显著的空间分异规律,各地区空间差异性明显,呈现出东北>中部>东部>西部的空间分布格局。③我国省际水-能源-粮食耦合协调度呈正向空间自相关性,集聚状态明显,但分布格局不够稳定,易发生变动。④我国省际水-能源-粮食耦合协调度的影响因素主要有经济发展水平、经济集聚、技术进步、教育、人口和农林支出。因此,国家应针对水、能源、粮食的协调发展进行顶层设计,统筹考虑水、能源、粮食与产业布局及行业外部影响的关系。通过技术进步来提升水、能源、粮食的利用效率,保证协调发展的质量。各省市则应结合自身实际情况,制定有针对性的措施,弥补短板,促进其水-能源-粮食的协调发展。  相似文献   
588.
China is preparing to establish a nationwide carbon market in 2017, and in order to facilitate this goal, seven pilot carbon markets have been under study for the past few years. This paper summarizes the operation experience and challenges of the seven pilot carbon markets in China. It has been widely accepted that the essence of a carbon market is to solve environmental problems through market mechanisms, with environmental benefit being the fundamental purpose, market mechanism being the key measure, and policies and regulations being an important guarantee for an orderly carbon market. Therefore, this paper constructs an evaluation index system composed of 34 detailed sub-indexes in three dimensions, such as environmental constraint force, market resource allocation ability, and supporting policies and facility completeness. Through analyzing the operation data from 2013 to 2016, the weights of the sub-indexes are obtained. In addition, the study obtains experts’ opinions from over 10 carbon permits exchanges, consultancy firms and research institutions in China, and conducts a comprehensive evaluation on the development degree of the seven pilot carbon markets. Results show that the pilot carbon markets that include private SMEs as the covered entities for emissions control present relatively higher environmental constraint force. But too many covered entities could increase the difficulty of market performance management, while the pilots that include high energy-consuming state-owned enterprises as the entities for emissions control demonstrate a phenomenon of “high market compliance rate with low trading volume”. The resource allocation capability of China’s carbon market has not been effectively brought into play, and low degree of market participation has become an important constraint factor for market development. Due to the lack of laws and regulations at the national macro-level, the legally binding force of the pilot markets construction is obviously insufficient, and the supporting policies are lacking foresights. Generally, the development of China’s pilot carbon markets is still in such a fragmented state as in the aspects of environment, market and policy development, and the market operation has not yet achieved the purpose of solving environmental problems through market mechanisms. Accordingly, policy recommendations pointed out by this study are that tightening the allowance of free quota and progressively increasing the auction proportion, improving legal construction, increasing the services and products of carbon finance and standardizing the order of market transactions, enhancing capacity building of local governments and promoting the participation willingness and capability of emissions control entities, will be necessary.  相似文献   
589.
Objective: Driving speed is a major concern for driving safety under reduced visibility conditions. Many factors affect speed selection in low visibility, but few studies have been conducted examining drivers' characteristics, particularly in China. The present study aimed to investigate the correlation between drivers' demographic information, driving ability, and speed choice in low-visibility conditions using a sample of Chinese drivers.

Methods: A self-designed driving ability scale was used to assess driving ability in reduced visibility conditions. The reliability and validity of 306 gathered questionnaires were examined in this article, and a structural equation model (SEM) was built to explore the predictors of drivers' speed selection behavior under reduced visibility conditions and to measure the relationships between various factors.

Results: Age and driving experience have no direct relationship to speed selection behavior in reduced visibility, but the frequency of using expressways and annual mileage are significantly related to the speed on roads that have a speed restriction of 80 or 120 km/h. Under reduced visibility conditions, driving ability has a significant effect on speed selection behavior, and driving skill (DS) is the most influential on speed selection behavior on roads with a speed limit of 120 km/h; otherwise, the effect of risk perception (RP) does not differ by speed choice on 3 roads with different speed limits. Driving speed in good weather also has a positive influence on speed selection behavior in low visibility.

Conclusion: Driving ability is directly associated with speed selection in reduced visibility conditions, and some demographic data indirectly influence speed selection. This study provides useful recommendations for drivers' training programs to reduce casualties from accidents in low-visibility conditions.  相似文献   

590.
农户是秸秆机械化还田服务的直接受益者,从农户视角来评价秸秆还田服务绩效水平,并诊断其可能的障碍因子,可为提高秸秆还田服务绩效提供决策依据。从秸秆还田服务过程和秸秆还田服务结果两个阶段、农户经济人属性和社会人属性两个方面构建秸秆机械化还田服务绩效评价指标体系,采用基于熵权改进的TOPSIS法和障碍度模型,通过对冀、鲁、皖、鄂四省农户的问卷调查,评价秸秆机械化还田服务绩效水平及障碍因子。结果显示:山东省秸秆机械化还田服务绩效水平为“优秀”,河北省的绩效水平“一般”,湖北省和安徽省绩效水平“较差”。秸秆机械化还田服务绩效水平最重要的影响因素是农户对秸秆机械化还田结果的评价,其次是还田过程阶段的评价;影响秸秆机械化还田服务绩效水平的主要因子为还田服务后社会发展情况、耕地病虫害情况、还田政策补贴及还田后耕地熵情的评价。为此,提高秸秆机械化还田服务的绩效水平,加强对秸秆机械化还田服务的宣传推广,积极完善秸秆机械化还田补贴等政策措施,提高还田后配套化设施及服务供给,应是当前政策关注的重心。  相似文献   
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