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排序方式: 共有952条查询结果,搜索用时 46 毫秒
1.
孙英潮 《科技和产业》2021,21(2):238-242
基于严寒区京沈客专朝阳试验段路基基床的温度监测资料分析,研究不同厚度聚氨酯保温板对高速铁路路基混凝土基床温度变化特性影响.测试结果表明:①铺设聚氨酯保温板能够有效阻断严寒区环境与路基基床间的热量传递,保温效果与板厚相关;②地温大多数时间呈阳高阴低现象,同时阴、阳坡路基温差波动幅度随埋深逐渐减小;③基床表层阴、阳面各测点的温度变化起始时间一致,而阴面的冻结时间比阳面晚一个月.由此表明,保温板能够有效降低环境与混凝土道床之间的热交换,但是对路基阴、阳坡的影响存在差异.建议在严寒地区高速铁路路基阳、阴坡可以采取不同厚度的聚氨酯保温板,减小阴阳坡地温差异,保持季冻土路基温度变化稳定.  相似文献   
2.
张震  郑檩  张雷  靳晔 《科技和产业》2021,21(2):243-248
为研究自动涂胶系统的胶枪最优材质、最佳热源位置和最佳测温位置,利用ANSYS Workbench软件对自粘胶胶枪进行数值模拟.通过分析不同材质胶枪的温度场分布情况,结合经济性和加热性能,选定最优胶枪基材.同时分析得出加热自粘胶至工作温度的时间和保持工作温度的加热功率,确定了热源和测温点位置,拟定了升温策略.进行自粘胶胶枪加热试验,验证了仿真分析结果的准确性.  相似文献   
3.
This research explored the leisure meanings of three African women, former refugees resettled in Canada. Using a hermeneutic phenomenological approach, this study revealed that leisure meanings were tightly bound in the women’s Christian faith, church, and faith community in affording them solace, socialisation, and community bonding. Furthermore, learning for leisure emphasised leisure for educational advancement, self-improvement, and knowledge-gain, to keep busy, and for companionship. Physically active leisures afforded fitness and fun, while nature-based leisure, particularly with friends, family, and their ethnocultural communities were important for restoration, nurturing relationships, and fostering social networks. These leisures also served to mitigate traumatic memories and stress. Because of the prominence of their Christian faith and the church as central to these women’s leisure, collaborative efforts by faith-based entities, leisure and recreation organisations and practitioners, settlement agencies, and mental health bodies, are recommended to effectively address the challenges and aspirations of resettled African women refugees through leisure.  相似文献   
4.
Although attention to the business risks posed by natural disasters fueled by climate change has grown, the toll that disasters have on human resources in the form of traumatic stress is comparatively neglected. It is common for more than 20% of people exposed to natural disasters to develop traumatic stress disorders that can last for years. In the workplace, traumatic stress hurts attendance, the quantity and quality of output, and relationships. Fortunately, businesses can promote employee resilience and recovery. Given the Asia-Pacific region’s high risk of natural disasters, businesses operating there should include employees’ traumatic stress in their disaster preparedness.  相似文献   
5.
This study investigates the relationships between challenge and hindrance stressors and hotel employees’ interpersonal citizenship behaviors (ICB). The study also tests the moderating role of hotel employees’ psychological capital (PsyCap) on the aforementioned relationships. Data were collected from 213 U.S. hotel frontline employees. The results showed that both challenge and hindrance stress had a negative relationship with ICB. PsyCap was found to moderate both relationships. Implications for hospitality researchers and industry practitioners are discussed along with the limitations and suggested avenues for future research.  相似文献   
6.
2017年,我国环保部门完成了火力发电等行业的排污许可证的核发,对我国建设排污权交易制度和实现“一证式”环境管理体制具有重要意义。围绕排污许可证中污染物的排放许可限值展开研究,应用脱钩原理对我国2003—2017年火力发电行业SO2排放与经济增长之间的脱钩关系进行分析,并基于脱钩理论,结合灰色预测方法GM(1,1)并运用情景假设法分析评价了排污许可证对我国2018—2020年火力发电行业SO2排放的约束作用强弱及其合理性,并提出建议。  相似文献   
7.
The COVID-19 pandemic has hit the hospitality industry hard globally, resulting in millions of employees being laid off. Drawing upon the conservation of resources theory, this study aims to empirically examine how and when COVID-19-induced layoff influences employees’ in-role and extra-role performance in the hospitality industry. We tested this model by using field data collected from 302 employees and their supervisors in China across two waves. Results revealed that COVID-19-induced layoff increases survivors’ COVID-19-related stress, which in turn leads to decreased in-role and extra-role performance. The strength of these indirect effects is mitigated by perceived family support against COVID-19. Unexpectedly, perceived organizational support against COVID-19 intensifies these indirect effects. The theoretical and practical implications of this study are further discussed.  相似文献   
8.
Drought tolerant (DT) maize varieties have received massive support in sub‐Saharan Africa because of their potential to protect smallholder farmers against drought‐related maize yield losses. Using four waves of household farm panel data from six districts in Malawi, we examine the impact heterogeneity of this technology on maize productivity using a continuous treatment approach. We find strong evidence of positive correlation between maize yield and adoption of DT maize varieties. On average, an increase by one hectare in the area allocated to DT varieties increases maize yield by 547 Kg/ha representing a 44% increase from the average maize yield of 1,254 Kg/ha for our sample. Our findings give evidence that DT maize technology has potential to protect smallholder farmers against drought‐related production losses. Policies that promote increased allocation of maize area to DT maize hold potential to enhance food security. Smallholder farmers especially in drought‐prone areas should be encouraged to allocate at least one‐third of the maize plot to DT varieties while breeders continue with the efforts of breeding a DT variety that is not only drought tolerant but also adapted to all weather conditions. More importantly, the government should ensure provision of timely ex ante weather information to guide farmers on decision‐making with respect to maize varietal choices.  相似文献   
9.
Abstract

Perceived work-related stress has increased notably in recent years, reducing individuals’ well-being and increasing organizations’ and economies’ costs. This study focuses on worktime control as a key approach to reducing work stress, as the extant research on its effects reports inconsistent results. The study argues that comparisons play a major role in how work stress, conceptualized as effort-reward imbalance, occurs. Ordinary least squares is used to test hypotheses with a sample of 1721 employees from Germany to determine whether employees’ prior worktime control and employees’ referents’ worktime control affect the relationship between worktime control and work stress. Results show that (1) worktime control is negatively associated with the experience of work stress, (2) employees’ prior worktime control moderates the relationship between worktime control and work stress, and (3) there is no moderating effect of employees’ referents’ worktime control. The results are discussed in light of gift-exchange theory and related empirical findings.  相似文献   
10.
We introduce the job crafting competency construct and apply it to predict tradeoffs between competing outcomes that are inherent in job crafting, like performance and well-being or engagement and withdrawal. Job crafting competencies are the clusters of individual knowledge, skills, and abilities that are necessary to achieve personal objectives through effective job crafting problem-solving. We create a framework of job crafting competencies consisting of comprehensive/simplistic heuristic information use and approach/avoidance problem-solving skills. In Study 1, we operationalize competencies as profiles demonstrated through an aptitude-oriented assessment that predicts differences in outcomes. Five distinct profiles emerged in a sample of 174 workers. The high-volume analytic problem-solving profile was associated with higher performance and strain, while the ambivalent acquiescence profile was associated with lower performance and strain. The practical problem-solving profile minimized tradeoffs between performance and strain. Rapid problem-solving and low-volume analytic problem-solving profiles were variants in between these other patterns. Study 2 used a survey of 323 workers to support the uniqueness of the five competencies, and their relationships with approach/avoidance job crafting, engagement, and withdrawal. The research identifies a new job crafting individual difference (job crafting competencies) to delineate outcomes and tradeoffs according to unique competency profiles.  相似文献   
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