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151.
文章通过选取几种不同的絮凝剂进行研究,来选出对木糖废水处理效果最佳的絮凝剂及其最佳絮凝条件、最佳去除率。从硫酸铝、三氯化铝、PAC、硫酸铁、硫酸亚铁、三氯化铁中选出PAC和Al2(SO4)3,然后针对这两种絮凝剂,研究确定其最佳絮凝条件及最大去除率。PAC的最佳实验条件为:投加量为1.6 g/L,pH=6,快速搅拌时间为30 s,沉降时间为30 min;Al2(SO4)3的最佳实验条件为:投加量为1 g/L,原水pH=6,快速搅拌时间为90 s,沉降时间为30 min。絮凝效果为:COD去除率分别为82.3%和75.38%,色度去除率都达到了90%以上。 相似文献
152.
目前油田修井作业现场生产方式存在信息不畅通的问题,无法实时跟踪监控井场安全生产运行情况和设备安全运转情况。研究应用"修井作业现场3G网络视频监控系统",能很好的解决作业现场视频信息及时交换问题,较好的解决了较偏远的作业队督查、监控问题,提高油田修井作业现场安全管理和应急管理水平。 相似文献
153.
在数学教学中,认知固然重要,但情感因素对学习者的影响也不可忽视。积极的情感因素可以激发学生的学习兴趣,从而提高学习成绩。 相似文献
154.
随着测绘科技的进步和现代技术的发展,信息技术日新月异,各领域的新技术层出不穷。在地籍测绘领域中,新技术和设备也在不断更新,随着GIS、RS、GPS(RTK)等技术的不断发展,对促进地籍测绘技术的进步和跨越式发展具有十分重要的意义和作用,这为地籍测绘领域的发展和进步作出巨大的贡献。 相似文献
155.
电子商务是指以互联网为整体架构,网络交易为主要内容,交易双方为主体,网上支付为手段,网络客户数据库为依托的全新的商务运作模式.我们着重分析基于B2B模式的电子商务在未来的巨大发展前景. 相似文献
156.
Sudipto Sarkar 《Journal of Macroeconomics》2011,33(4):681-689
Corporate investment is an important determinant of economic well-being. The existing literature identifies optimal investment size and timing without the possibility of debt financing, as well as the effect of debt financing on investment timing without the option to choose investment size. This paper contributes to the literature by identifying the optimal size, optimal timing and optimal financing for an investment when the firm controls all three decisions (as it usually does in practice). The investment size and investment trigger are generally positively related: when investment is delayed (accelerated) it is larger (smaller) in size, thus the overall effect on investment is ambiguous. However, when tax rate or bankruptcy cost is increased, the trigger rises and size falls, hence the effect on investment is unambiguously negative. The effect of debt financing on investment depends on the amount of debt used; with the optimal amount of debt, investment is delayed relative to the no-debt case, and this delay can be economically significant; however, the investment, when eventually made, will be larger in size. Overall, it is not appropriate to ignore either the firm’s ability to choose investment size or its option to use debt financing, when modeling the investment decision. 相似文献
157.
We show that attractiveness, as measured by facial symmetry, leads to greater rewards in professional sports. National Football League quarterbacks who are more attractive are paid greater salaries and this premium persists after controlling for player performance. 相似文献
158.
In this paper we examine long-run house price convergence across US states using a novel econometric approach advocated by Pesaran (2007) and Pesaran et al. (2009). Our empirical modelling strategy employs a probabilistic test statistic for convergence based on the percentage of unit root rejections among all state house price differentials. Using a sieve bootstrap procedure, we construct confidence intervals and find evidence in favour of convergence. We also conclude that speed of adjustment towards long-run equilibrium is inversely related to distance. 相似文献
159.
Paul Collier 《Journal of development economics》2011,94(2):202-206
Where imports are financed predominantly by rents from resource extraction or aid the revenue generated by tariffs is illusory. Revenue earned by the tariff is offset by a reduction in the real value of aid and resource rents. Revenue is however moved between accounts in the government budget which, in the case of aid, may reduce the burden of donor conditionality. We demonstrate this proposition for a simple central case and show that the result is not overturned by generalisations around this case. We argue that trade policy formulation in such economies should recognize the illusory nature of tariff revenues. 相似文献
160.
In this paper, we adopt a recent OECD framework and examine the role of external policy tools and internal firm specific factors for stimulating three different types of eco-innovations that range on a spectrum of lower to higher technological and environmental impacts: End-of-Pipeline Pollution Control Technologies, Integrated Cleaner Production Technologies and Environmental R&D. Using a novel firm-level dataset from a DEFRA survey, we estimate a Tobit model, which provides empirical evidence showing that these eco-innovations are motivated by different external policy tools and internal firm specific factors. Our findings indicate that End of Pipeline Technologies and Integrated Cleaner Production Technologies are mainly driven by equipment upgrade motives with a view of improving efficiency while environmental regulations are effective in stimulating the End-of-Pipeline technologies and Environmental R&D. Interestingly, alongside government induced regulations, we find that market factors, mainly motivated by cost savings, are effective in driving Environmental R&D. Finally, ISO14001 certification is effective in strengthening the positive impact of environmental management systems on both End-of-Pipeline technologies and Environmental R&D while CSR policies have no significant impact on motivating any of the eco-innovations. 相似文献