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11.
本文用水热法生长了Al~(3+):α-SiO_2石英晶体,测量了γ射线辐照赋色的晶体的吸收光谱。主要的可见吸收带位于2、61ev,2.07ev和2.30ev处。其中2、6ev和2、07ev吸收带是GOW心(即〔Al_(e+)〕°心)产生的色心吸收带。本文理论上计算了GOW心的电子能态。对应该心两个吸收带的理论值分别位于2、72ev和1.94ev与实验结果相符。  相似文献   
12.
介绍了一种电子信息专业词典。该词典在0FFICE的ACCESS软件平台上设计开发,成为一种专业术语的数据库系统。该系统具有编辑和查询两大功能,录入了上万条电子信息专业词汇。利用系统的编辑功能,还可以对词汇动态更新,弥补了一般专业词典更新缓慢的缺陷。词典结合教学内容对词条的专业解释,使词典成为某种意义上的电子专业百科书,有助于拓展学生的专业知识和教学工作。  相似文献   
13.
Many thousands of people in developing country cities depend on recycling materials from waste for their livelihoods. With the focus of the Millennium Development Goals on poverty reduction, and of waste strategies on improving recycling rates, one of the major challenges in solid waste management in developing countries is how best to work with this informal sector to improve their livelihoods, working conditions and efficiency in recycling.The general characteristics of informal recycling are reviewed, highlighting both positive and negative aspects. Despite the health and social problems associated with informal recycling, it provides significant economic benefits that need to be retained. Experience shows that it can be highly counterproductive to establish new formal waste recycling systems without taking into account informal systems that already exist. The preferred option is to integrate the informal sector into waste management planning, building on their practices and experience, while working to improve efficiency and the living and working conditions of those involved. Issues associated with integrating informal recycling into the formal waste management sector are discussed.  相似文献   
14.
蒲松  夏嫦 《中国管理科学》2021,29(5):166-172
城市医疗废弃物日益增加,且回收需求量受诸多因素的影响,难以准确预测,假定回收需求为确定值的医疗废弃物网络优化设计不能与实际需求相匹配。本文考虑了离散随机参数环境下,医疗回收网络设计中选址规划、分配计划及运输规划的协同优化问题,建立了以选址成本、运输成本最小为目标,设施与车辆能力限制为约束的二阶段随机规划模型。根据模型特点,设计了基于Benders decomposition的求解算法,同时,设计了一系列加速技术用于提高算法的求解效率。最后,以国内某城市医疗回收网络为背景设计算例,检验本文模型和求解策略的可行性和有效性。结果表明:相比确定性规划,随机规划的解能够节约总成本,结合一系列加速技术的Benders decomposition方法比CPLEX与纯的Benders decomposition更有优势。  相似文献   
15.
David Gefen  Detmar W. Straub   《Omega》2004,32(6):1337
Reducing social uncertainty—understanding, predicting, and controlling the behavior of other people—is a central motivating force of human behavior. When rules and customs are not sufficient, people rely on trust and familiarity as primary mechanisms to reduce social uncertainty. The relative paucity of regulations and customs on the Internet makes consumer familiarity and trust especially important in the case of e-Commerce. Yet the lack of an interpersonal exchange and the one-time nature of the typical business transaction on the Internet make this kind of consumer trust unique, because trust relates to other people and is nourished through interactions with them.This study validates a four-dimensional scale of trust in the context of e-Products and revalidates it in the context of e-Services. The study then shows the influence of social presence on these dimensions of this trust, especially benevolence, and its ultimate contribution to online purchase intentions.  相似文献   
16.
The evaluation of hazards from complex, large scale, technologically advanced systems often requires the construction of computer implemented mathematical models. These models are used to evaluate the safety of the systems and to evaluate the consequences of modifications to the systems. These evaluations, however, are normally surrounded by significant uncertainties related to the uncertainty inherent in natural phenomena such as the weather and those related to uncertainties in the parameters and models used in the evaluation.

Another use of these models is to evaluate strategies for improving information used in the modeling process itself. While sensitivity analysis is useful in defining variables in the model that are important, uncertainty analysis provides a tool for assessing the importance of uncertainty about these variables. A third complementary technique, is decision analysis. It provides a methodology for explicitly evaluating and ranking potential improvements to the model. Its use in the development of information gathering strategies for a nuclear waste repository are discussed in this paper.  相似文献   
17.
现代城市垃圾治理是一项复杂的系统工程。在城市垃圾中,生活垃圾所占比重大、与民众联系密切且处理阻力大,对城市生活垃圾治理的战略设计已成为城市管理者面临的最大难题之一。作为我国重要中心城市的广州,也正面临形势严峻的"垃圾围城"之困,自2012年开启新一轮城市生活垃圾综合治理以来,在有创新、有收获的同时也遇到了新的挑战。为进一步深化城市生活垃圾治理工作,广州应准确把脉顶层制度难"落地"、流程运行难系统、民众习惯难转变等现实症结,科学设计生活垃圾的多元共治路径,实现挑战与机遇的对接,为我国城市生活垃圾的治理树立标杆,助推开创城市垃圾治理的新局面。  相似文献   
18.
19.
BackgroundMoral judgements are commonly directed towards mothers through reference to health behaviour in pregnancy, and working-class mothers are particularly subject to this moral gaze.AimTo gain an in-depth understanding of the health issues affecting 10 low income pregnant women from deprived areas of south Wales, UK.MethodsParticipants completed visual activities (timelines, collaging or thought bubbles and dyad sandboxing) prior to each interview. Participants’ visual representations were used in place of a topic guide, to direct the interview. Guided by feminist principles, 28 interviews were completed with 10 women. Data were analysed thematically.FindingsSmoking was discussed at length during interviews, and this paper focuses on this issue alone. Five of the participants had smoked during pregnancy. Negative reactions were directed towards pregnant women who smoked in public, resulting in maternal smoking being undertaken in private. Participants also reported awkward relationships with midwives and other health professionals, including receipt of public health advice in a judgemental tone.DiscussionSmoking during pregnancy is a particularly demonised and stigmatised activity. This stigma is not always related to the level of risk to the foetus, and instead can be seen as a moral judgement about women. We urgently need to move from individualised neo-liberal discourses about the failure of individual smokers, to a more socio-ecological view which avoids victim blaming.ConclusionStigma from friends, family, strangers and health professionals may lead to hidden smoking. This is a barrier to women obtaining evidence based stop smoking support.  相似文献   
20.
近年来,发达国家电子废弃物的流入给发展中国家的环境和民众健康带来了严重的危害。我国在阻止电子废弃物流入的相关法律规制与监管上存在漏洞,且经济发展战略不合理,发展水平相对落后。法律和经济方面的双重落差导致发达国家电子废弃物流入屡禁不止,迫切需要采取有效措施加以应对。分析国外电子废弃物涌入我国之现状与原因,并从法律制度建设、经济发展思路、经济发展战略、国内管理和国际合作5方面提出应对策略。  相似文献   
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