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471.
陕西省城市化与生态环境系统耦合关系 总被引:1,自引:0,他引:1
采用层次分析法(AHP)和系统科学的理论构建了城市化与生态环境系统的评价指标体系和耦合模型,并将这个耦合系统的演化周期分为低级共生、协调发展等4个阶段,根据耦合度为45°时,耦合效果最佳的理论又可将协调发展阶段分为相对协调、最佳协调、低度协调3个状态.1990-2008年陕西省的城市化综合指数呈现直线上升的趋势,生态环... 相似文献
472.
保护生态系统、提高居民福祉是实现联合国2030可持续发展目标的核心内容。在分析秦巴山区生态系统服务与居民福祉时空演化特征的基础上,采用弹性系数揭示了二者的时空耦合关系。研究发现:(1)1990—2018年秦巴山区水源涵养总量、土壤保持总量均呈波动下降趋势,碳储量总量则呈缓慢增长趋势,且各生态系统服务呈不同的空间分异特征。(2)1990—2018年居民福祉呈上升趋势,增幅高达220%,并呈“南高北低”的分布格局。(3)县域尺度上,三种生态系统服务与居民福祉明显不协调发展。其中,水源涵养、固碳服务与居民福祉的耦合关系均以“福祉增—服务减”为主,占比分别为88.75%、62.5%;而土壤保持服务与居民福祉的耦合关系则以“双增”为主,占比为57.5%。此外,各项生态系统服务与居民福祉反向变化区多分布于汉江河谷盆地和秦岭山脉中段。研究结果可为促进贫困山区生态系统服务与居民福祉协调发展提供决策依据。 相似文献
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Although transformational leadership has been investigated in connection with change at higher levels of organizations, less is known about its “in‐the‐trenches” impact. We examined relations among transformational leadership, explicit change reactions (i.e., relationship quality), change frequency, and change consequences (i.e., task performance and organizational citizenship behavior (OCB)) during continuous incremental organizational change at lower hierarchical levels. In a sample of 251 employees and their 78 managers, analyses revealed that the quality of relationships between leaders and employees mediated the influence of transformational leadership on employee task performance and OCB. We also found that change frequency moderated the positive association of relationship quality with task performance and OCB, such that associations were stronger when change frequency was high. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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Tzai-Zang Lee Chih-Wei Hong 《International journal of occupational safety and ergonomics》2013,19(3):255-269
Although the social exchange relationships between employers and employees are increasingly important to the performance of safety management systems, the psychological effects of work attitudes on this relationship have been less studied. Using a sample of first-line operators and their supervisors from 188 facilities in Taiwan which had Occupational Health and Safety Assessment Series 18000 (OHSAS 18000) certification, the current research conducted an empirical investigation of the influence of safety climate on organizational citizenship behavior (OCB). Work attitude was used to disclose the psychological effect. Research results indicated that (a) safety climate was a significant predicator of OCB, (b) the psychological effect significantly influenced social exchange relationships, and (c) job satisfaction showed a stronger mediating influence than organizational commitment due to the frequent top management turnover. Discussions and implications are also addressed. 相似文献
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478.
《Environmental Communication: A Journal of Nature and Culture》2013,7(4):520-538
Aron Ralston and Christopher McCandless, two outdoor adventurers, have captured the hearts of many American environmentalists. Each has attained the status of cultural icons and inspired books and films to recount their tales. While entertainment media have romanticized both individuals, news media are not as easy on one—McCandless is vilified while Ralston is valorized. When reporting these stories, news media outlets attempted to retell each story in a way that conforms to the dominant American ideology of wilderness, where “progress” is marked by control over nature—control that both Ralston and McCandless clearly unsettled. In addition, both committed many of the same errors in being underprepared. Despite these similarities, why are they each presented so differently in the news media? This paper offers a rhetorical analysis of newspaper articles on each story, where the phenomenon of scapegoating alienates McCandless, and the phenomenon of mortification purifies Ralston, restabilizing this American environmental ideology in both stories. In conclusion, I argue that the essential difference between these two stories is that they present two opposing ideals of a human–nature relationship, with Ralston's ideology including a space for technology and industrial knowledge, and thus construed as more appropriate than McCandless' ideology. 相似文献
479.
Polyols and Polyurethanes from Hydroformylation of Soybean Oil 总被引:10,自引:0,他引:10
Andrew Guo Dima Demydov Wei Zhang Zoran S. Petrovic 《Journal of Polymers and the Environment》2002,10(1-2):49-52
This paper compares physical and mechanical properties of polyurethanes derived via the hydroformylation approach and is a part of our study on the structure–property relationships in polyurethanes created from vegetable oils. The double bonds of soybean oil are first converted to aldehydes through hydroformylation using either rhodium or cobalt as the catalyst. The aldehydes are hydrogenated by Raney nickel to alcohols, forming a triglyceride polyol. The latter is reacted with polymeric MDI to yield the polyurethane. Depending on the degree of conversion, the materials can behave as hard rubbers or rigid plastics. The rhodium-catalyzed reaction afforded a polyol with a 95% conversion, giving rise to a rigid polyurethane, while the cobalt-catalyzed reaction gives a polyol with a 67% conversion, leading to a hard rubber having lower mechanical strengths. Addition of glycerine as a cross-linker systematically improves the properties of the polyurethanes. The polyols are characterized by DSC. The measured properties of polyurethanes include glass transition temperatures, tensile strengths, flexural moduli, and impact strengths. 相似文献
480.
污染物排放量与河流水质输入响应关系的建立,是实施排污总量控制的关键.文章以小清河(济南段)为例,将小清河分为睦里庄-还乡店段,还乡店-大码头段和大码头-辛丰庄段,应用一维稳态河流水质模型,确定相应模型参数,与水质实测值相结合,建立污染物排放量与河流水质的输入响应关系,计算响应系数.结果表明:小清河不同段COD的响应系数分别为94.3%、76.7%和76.6%,氨氮的响应系数分别为277.2%、85.7%和58.8%;COD的计算值与实测值比较接近,而睦里庄-还乡店段、大码头-辛丰庄段氨氮的计算值与实测值偏差较大. 相似文献