美国调频辅助服务市场的调频补偿机制分析

合理的补偿机制是调频辅助服务市场正常运行的重要保障。为进一步促进调频资源的优化配置,美国调频辅助服务市场引入了基于调频效果的补偿机制。文中对比分析了美国宾夕法尼亚—新泽西—马里兰州、加利福尼亚州、纽约、新英格兰和中西部电力市场区域的最新调频补偿机制,包括补偿结算规则、调频里程与调频性能指标的计算方法等。最后,结合当前国内电力体制改革的现状提出建立调频辅助服务市场和调频补偿机制的相关思路和建议。     

An analysis of construction productivity differences between Canada and the United States

Comparisons of industry sectors in advanced economies since the 1960s show that the construction sector has lagged in productivity growth rates, especially in the United States. Although the US and Canadian economies are highly integrated, Canada’s experience differs in key ways. Analysis of these differences offers insight into fundamental construction productivity drivers. Three levels of analyses of construction productivity in the US are provided in this study. The first analysis compared international levels of labour productivity growth. The second compared construction productivity between the US and Canada, and the third analysed cost estimating data from RS Means estimating manuals to measure the changes in labour and partial factor productivity in the US from 1995 to 2009. Statistical significance testing indicates that labour productivity remained nearly constant in the building sub-sector and that partial factor productivity has improved at an annual compound rate of 0.66%. This supports previous findings that US construction has stagnated but is still improving in Canada, with wage differentials and training systems as potential drivers of this difference. While growth rates of productivity seem to decline with higher absolute levels of productivity, there is no evidence that high absolute productivity levels preclude significant growth.     

Differences in cardiovascular mortality rates among hemodialysis patients in the United States and Japan: The importance of background cardiovascular mortality

Mortality rates among hemodialysis patients differ greatly among the United States, Europe, and Japan and it has been hypothesized that this is mainly due to differences in practice patterns. Results from the international DOPPS study, however, indicate that differences in practice patterns among the United States, Japan, and Europe are small and not alone explanatory for the differences in mortality rates. Ethnic variability in predisposition to atherosclerotic cardiovascular disease in the general population may lead to significant differences in background cardiovascular mortality in the United States, Japan, and Europe. It is our hypothesis that cardiovascular mortality in dialysis patients is to a great extent dependent on cardiovascular background mortality of the general population. We are currently studying the relationship between all‐cause and cardiovascular death rates in countries worldwide using the WHO database. Preliminary data from 35 countries show that all‐cause and cardiovascular death rates differ significantly among regions, with Eastern European countries reporting four‐ to sevenfold higher death rates than Asian countries. A strong linear relationship between cardiovascular and all‐cause death rates is observed among these countries. The next step of our study will be to compare country‐specific cardiovascular death rates of dialysis populations with those of the respective general populations. Ethnic differences in cardiovascular morbidity and mortality may be explained by genetic variability based upon polymorphism of genes involved in the pathogenesis of atherosclerosis and myocardial infarction.     

Security of Payment Legislation—Case of a Blunt but Practical and Equitable Instrument

In the modern world, some traditions are falling faster than others. The threat to end the legal concept of freedom of contract may be realized sooner than expected with the statutory interference of not only consumer contracts but contracts between nonconsumers. The family of security of payment legislation, beginning from the United Kingdom has been adopted by New South Wales and now in Singapore, regulates a business-to-business contract to facilitate progress payment in the construction industry by introducing statutory adjudication to resolve disputes producing the effect of nonpayment. The struggle between two parties, one with a right to demand payment and the other with the right to withhold payment because of his right to set-off and counter-claim, is examined in light of the new legislation called the Singapore Building and Construction Industry Security of Payment Act 2004. Having examined specific provisions of the Act and the experience of New South Wales—as Singapore has no relevant case law, it is concluded that the Act is a blunt but practical and equitable instrument to achieve its intention.     

The Development Of Ozone For Potable Water Treatment Within The United Kingdom

The historical development of the application of ozone to potable water treatment within the United Kingdom is reviewed up to 1990. The impact of privatization of the water utilities on the use of ozone is discussed and the process applications currently being considered are described. The paper concludes with a survey of water treatment plants which are using ozone in 1993, and those planned for completion by the year 2000.     

Short rotation woody crop plantations in Brazil and the United States

The Short Rotation Woody Crop (SRWC) concept has been applied in the establishment of experimental and commercial plantations in both the United States and Brazil. The SRWC concept involves the application of agricultural principles to the production of tree crops for fiber or fuel. Although extensive SRWC research has occurred in the United States during the past 10 to 16 years, commercial applications have been rather limited. On the other hand, Brazil has made considerable progress in producing SRWC on a large-scale commercial basis while simultaneously conducting research. It seems clear that both countries can gain from each other's experience in SRWC experimentation and commercialization. This paper discusses and compares SRWC system developments in both countries and suggests means of improving and expanding SRWC systems use.     

Review of the United States Refractories Industry

Factors affecting the U.S.refractories industry,such as decreasing demand,mergers ,and decreased education are discussed,along with manufacturing statistics(i.e.,annual value and product trends),indicating that the U.S.market has declined for five straight years,.Research activities have changed,with more emphasis on practical,applied projects,which have continued to produce important advances,Many challenges and opportunities remain,based on the current and future business requirements.     

中央亚利桑那工程

由于地表水资源供给不足，亚利桑那卅l自20世纪60年代开始大规模超采地下水。为有效解决地下水超采伺题，同时促进亚利桑那州经济和社会发展，美国政府于20世纪90年代兴建了中央亚利桑那调水工程。该工程是一项大型远距离凋水工程，也是迄今为止美国水利丁程史上规模最大、费用最高的调水工程。工程主要建筑物包括渠道、泵站、倒虹吸、隧洞和大坝等。中央亚利桑那工程的主要目标是为亚利桑那州中南部地区提供农业、城市生活和上业用水，同时兼具防洪、发电、泥沙控制、娱乐等多项任务。主要介绍中央亚利桑那工程的建设背景、关键工程设施、工程管理和上程效益等方面的内容。     

Thermal efficiency of solid electrolyte fuel cells with mixed conduction

The effect of mixed anionic and n-type electronic conduction in solid electrolytes on the thermal efficiency of a fuel cell system was analyzed quantitatively. The mixed conduction observed when electrolytes based on ceria are used in H₂/air fuel cell applications lowers the maximum attainable cell thermal efficiency to below 40%. Neither the zirconia nor the ceria based solid oxide electrolytes studied to date can be used in a low temperature (700 °C) system that meets simultaneously the requirements of power density and thermal efficiency for electric utility power plants. The material properties required for an advanced fuel cell power plant solid electrolyte were derived in terms of the ionic conductivity and the Schmalzried parameters P⊕ and P? : σ_ion > 0.033 (ω-cm)^?1, P⊕ > 10³ atm., P? < 10^?23 atm. at 700 °C.     

Evaluation of United States of America psychology by the "four-years-absent" method.

Criticisms are leveled at psychology in the United States: (a) psychology, both as a discipline and as a profession is vague; (b) psychology lacks goals; (c) psychology is fragmented—the specialities are isolated from each other with little effective inter-communication; (d) psychology appears to be angry—the profession lacks harmony; (e) psychology is insecure—we have a status problem; (f) psychologists suffer from inbreeding—their views are often narrow; (g) psychology lacks tradition; (h) psychology has no modern heroes; and (i) psychologists have surrendered—not only do we lack a concept of self, but "we do not seem to seek one within the framework of our profession." Remedies are suggested. (PsycINFO Database Record (c) 2010 APA, all rights reserved)