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51.
谢桂杰 《价值工程》2015,(11):124-126
介绍工业锅炉酸洗中铁离子的来源,并以实例说明酸洗中应强化对铁离子、亚铁离子(Fe3+、Fe2+)的化学监测,使锅炉酸洗安全进行,及终点的判断。  相似文献   
52.
An economic growth target is a declaration by policy authorities of commitment to that target and the corresponding allocation of resources. The constraints created by economic growth target are an important economic management method in China, which has helped China's economy to achieve remarkable achievements. However, it has also brought about serious environmental problems, threatening China's sustainable development. Using the data about economic growth targets in the work reports of 30 Chinese provincial governments from 2006 to 2017, this paper constructs several spatial measurement methods, such as the spatial Durbin model, to examine the constraints created by economic growth target's impacts on air pollution. The main conclusions are as follows. First, a significant “U-shaped” relationship exists between the constraints created by economic growth targets and air pollution. Second, the spatial Durbin model analysis revealed that PM2.5 across China's provinces display significant positive spatial spillover effects and spatial agglomeration characteristics. Third, the direct, indirect, and total effects of constraints created by economic growth targets on air pollution are all statistically significant and depict a “U shape.” Finally, the constraints created by economic growth targets have an apparent threshold effect on air pollution, and the inhibiting effects increase with human capital and industrial restructuring. However, with the increase in foreign direct investments, constraints created by economic growth targets may increase air pollution. The conclusions of this paper are of great significance for improving the management of local government economic growth targets and sustainable development.  相似文献   
53.
近年来对菱角壳的研究主要分为化学成分和药理活性研究两个方面,其中化学成分方面的研究可以概括为生物碱、酚酸类、萜类和甾体、多糖类、黄酮类5个方面;药理活性方面的研究可以概括为抗癌活性、抗氧化活性、降低α-葡萄糖苷酶活性、保肝护肝活性、抗菌活性5个方面。目前在化学成分方面的研究较弱,从研究结果来看,没食子酸及其衍生物是菱角壳的主要药用成分。最后就菱角壳的开发利用提出了几点建议。  相似文献   
54.
就 业问题、环境污染以及从业人员研发能力下降已经成为制约软件外包承接城市发展的瓶颈问 题。文章运用DEA方法构建考虑非期望产出和非合意变量的软件外包承接效率评价模型,重 点比较不同模型下我国软件外包承接城市效率的差异,并引入Tobit回归分析软件外包承接 城市效率的驱动因素。研究发现:我国软件外包承接城市的投入产出组合在逐步优化,且东 部沿海城市的效率值明显优于中西部城市,其中大连市的效率值始终为1,处于生产的前沿 面。另外,人才竞争力对软件外包承接城市效率有显著的正向影响,信息技术基础设施竞争力与承接效率的关系呈显著负相关。  相似文献   
55.
Increased fertilizer use is considered important for agricultural development in low-income countries. Promoting increased use of chemical fertilizer by lowering its price may be ineffective if demand is price inelastic. In theory, the price elasticity of demand depends on the returns to its use, but the evidence is scarce. Furthermore, while returns are often estimated for small changes in chemical fertilizer use, returns to larger changes in its use (intensive margins) are less understood. Through the inter-zonal comparisons in Nepal, we provide indicative evidence that greater returns to chemical fertilizer are associated with greater price elasticities of demand. Moreover, the evidence suggests that returns at the intensive margins, rather than returns to small changes, may largely account for inter-zonal differences in returns to chemical fertilizer within Nepal. The results suggest that better understanding the returns at the intensive margins is critical for effective agricultural inputs policies in developing countries.  相似文献   
56.
Haze pollution has become the most important environmental issue in China in recent years. Using the data of PM2.5 concentration and stocks of listed companies located in Beijing between 2010 and 2014, this article investigates the effects of haze pollution on stock performances. Empirical results indicate that haze pollution has significant negative effects on stock returns and significant positive effects on stock volatilities, through the channel of investors’ mood. Furthermore, the effects of haze pollution on stock returns emerge gradually and the effects of haze pollution on stock volatilities weaken gradually over time during a trading day.  相似文献   
57.
外商直接投资在对中国经济增长起到积极推动作用的同时,我们也不可忽视其可能会对我国环境造成的影响。文章通过构建环境污染综合指数,并且以东中西部为三个横截面建立动态面板数据模型来分析外商直接投资对各个地区环境的影响。结果显示,外商直接投资和东部中部地区的环境污染指数之间有正相关关系,和西部地区的环境污染指数之间是一个负相关关系。  相似文献   
58.
Plastic pollution is a global environmental crisis that poses a huge threat to the health of people and marine ecosystems worldwide. A significant source of plastic pollution is menstrual hygiene management, and an approach that can help address this crisis is the usage of washable and reusable menstrual cups. Using an extended theory of planned behavior model that includes self-identity and perceived quality, the study predicted intentions to use menstrual cups in the Philippines. Structural equation modeling results showed that perceived quality predicted attitudes towards menstrual cup usage. Moreover, attitudes, perceived behavioral control, and self-identity predicted intentions to use menstrual cups. There were also some differences in the factors and predictors of intentions between non-users and regular users of menstrual cups. Among regular users, perceived behavioral control did not predict intentions. These findings provide empirical support for the extended model, and provides insights for governments, non-government organizations, and corporations in promoting the usage of menstrual cups to address the global plastic pollution crisis.  相似文献   
59.
周翠兰 《价值工程》2014,(11):324-325
本文介绍了汽车尾气对人类健康和生态环境的危害,及其生成机理和影响因素并简述汽车尾气治理与发展。  相似文献   
60.
Plastic bag litter generates serious environmental concerns and poses a risk to wildlife. As this does not seem to be a problem which can be resolved by the private sector alone, or by ‘Coasean’ negotiation, legislation is proposed, particularly focusing on ‘one‐use’ bags. This article surveys legislation worldwide, while concentrating on lessons from the United States and the United Kingdom. The issues are more complex than is often assumed. While environmentalists argue for restriction and ultimate elimination of one‐use bags, manufacturers, especially those that have reformulated the composition of their bags, see legislation as an overreaction to a problem that is already being addressed within the industry. They cite evidence that, when used within a comprehensive recycling programme, plastic bags are not only cost‐effective but a sound use of our limited resources. Bans or restrictions can have knock‐on effects which can create new problems.  相似文献   
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