本文标题中的GM并非目前的热门缩略词GM(genetically modi—fied,转基因)而是General Motors(美国通用汽车公司)的缩略词。汽车制造业在过去的20世纪中有了长足的进步。无疑,新世纪将能目睹汽车更大的质的飞跃。汽车制造商正在动用巨额...本文标题中的GM并非目前的热门缩略词GM(genetically modi—fied,转基因)而是General Motors(美国通用汽车公司)的缩略词。汽车制造业在过去的20世纪中有了长足的进步。无疑,新世纪将能目睹汽车更大的质的飞跃。汽车制造商正在动用巨额资金研制新型汽车,汽车制造业不断传来令人振奋的消息。《科技英语学习》曾经介绍过一种会飞的汽车,而本文则介绍了fuelcell concept vehicle(燃料电池新概念交通工具),这种汽车用liquid hydrogen(液态氢)驱动,fuel cell stack(燃料电池存储器)取代了传统的汽车发动机,它不仅符合环保要求,而且性能也极为优秀:行程达400公里/小时,时速达140公里。Fuel cell concept vehicle并非首次研制成功,研制人员在不断地改进完善其性能: Previous fuel—cell stacks took six minutes to reach full acceleration at freezingtemperatures,Wagoner said.The concept model developed takes 30 seconds.本文的末尾告诉我们在今年夏天的奥运会上,这种新型汽车将亮相。让我们拭目以待。展开更多
风电机舱用液浸式变压器客户要求进行油箱耐受试验,按照BS EN 50464—4:2007标准进行试验有许多限制条件,导致试验过程中存在一些干扰。为了达到同样的验证效果,本文提出了新的试验方法并实施验证,在试验过程中也发现了一些问题,在此提...风电机舱用液浸式变压器客户要求进行油箱耐受试验,按照BS EN 50464—4:2007标准进行试验有许多限制条件,导致试验过程中存在一些干扰。为了达到同样的验证效果,本文提出了新的试验方法并实施验证,在试验过程中也发现了一些问题,在此提出以供以后试验中予以注意。展开更多
Small modular reactors (SMRs) offer simple, standardized, and safe modular designs for new nuclear reactor construction. They are factory built, requiring smaller initial capital investment and facilitating shorter co...Small modular reactors (SMRs) offer simple, standardized, and safe modular designs for new nuclear reactor construction. They are factory built, requiring smaller initial capital investment and facilitating shorter construction times. SMRs also promise competitive economy when compared with the current reactor fleet. Construction cost of a majority of the projects, which are mostly in their design stages, is not publicly available, but variable costs can be determined from fuel enrichment, average burn-up, and plant thermal efficiency, which are public parameters for many near-term SMR projects. The fuel cost of electricity generation for selected SMRs and large reactors is simulated, including calculation of optimal tails assay in the uranium enrichment process. The results are compared between one another and with current generation large reactor designs providing a rough comparison of the long-term economics of a new nuclear reactor project. SMRs are predicted to have higher fuel costs than large reactors. Particularly, integral pressurized water reactors (iPWRs) are shown to have from 15% to 70% higher fuel costs than large light water reactors using 2014 nuclear fuels market data. Fuel cost sensitivities to reactor design parameters are presented.展开更多
This paper examines the factors that Uganda’s households consider when making fuel choices for cooking and investigates the key drivers of fuel choice. The study adopts a quantitative cross sectional research design....This paper examines the factors that Uganda’s households consider when making fuel choices for cooking and investigates the key drivers of fuel choice. The study adopts a quantitative cross sectional research design. The dependent variable of the empirical model is a qualitative response variable which defines three mutually exclusive and highly differentiated discrete choices for cooking fuels, namely: the traditional fuel (firewood), the transitional fuel (charcoal), and the modern (LPG & electricity). Results from the study show that the most important drivers of fuel choice for cooking in Uganda’s households are: household income, age of household head, gender of household head, marital status, education levels of household head and location of a household. Results also reveal high dependency of firewood as cooking energy source among households in Uganda.展开更多
文摘本文标题中的GM并非目前的热门缩略词GM(genetically modi—fied,转基因)而是General Motors(美国通用汽车公司)的缩略词。汽车制造业在过去的20世纪中有了长足的进步。无疑,新世纪将能目睹汽车更大的质的飞跃。汽车制造商正在动用巨额资金研制新型汽车,汽车制造业不断传来令人振奋的消息。《科技英语学习》曾经介绍过一种会飞的汽车,而本文则介绍了fuelcell concept vehicle(燃料电池新概念交通工具),这种汽车用liquid hydrogen(液态氢)驱动,fuel cell stack(燃料电池存储器)取代了传统的汽车发动机,它不仅符合环保要求,而且性能也极为优秀:行程达400公里/小时,时速达140公里。Fuel cell concept vehicle并非首次研制成功,研制人员在不断地改进完善其性能: Previous fuel—cell stacks took six minutes to reach full acceleration at freezingtemperatures,Wagoner said.The concept model developed takes 30 seconds.本文的末尾告诉我们在今年夏天的奥运会上,这种新型汽车将亮相。让我们拭目以待。
文摘Small modular reactors (SMRs) offer simple, standardized, and safe modular designs for new nuclear reactor construction. They are factory built, requiring smaller initial capital investment and facilitating shorter construction times. SMRs also promise competitive economy when compared with the current reactor fleet. Construction cost of a majority of the projects, which are mostly in their design stages, is not publicly available, but variable costs can be determined from fuel enrichment, average burn-up, and plant thermal efficiency, which are public parameters for many near-term SMR projects. The fuel cost of electricity generation for selected SMRs and large reactors is simulated, including calculation of optimal tails assay in the uranium enrichment process. The results are compared between one another and with current generation large reactor designs providing a rough comparison of the long-term economics of a new nuclear reactor project. SMRs are predicted to have higher fuel costs than large reactors. Particularly, integral pressurized water reactors (iPWRs) are shown to have from 15% to 70% higher fuel costs than large light water reactors using 2014 nuclear fuels market data. Fuel cost sensitivities to reactor design parameters are presented.
文摘This paper examines the factors that Uganda’s households consider when making fuel choices for cooking and investigates the key drivers of fuel choice. The study adopts a quantitative cross sectional research design. The dependent variable of the empirical model is a qualitative response variable which defines three mutually exclusive and highly differentiated discrete choices for cooking fuels, namely: the traditional fuel (firewood), the transitional fuel (charcoal), and the modern (LPG & electricity). Results from the study show that the most important drivers of fuel choice for cooking in Uganda’s households are: household income, age of household head, gender of household head, marital status, education levels of household head and location of a household. Results also reveal high dependency of firewood as cooking energy source among households in Uganda.
