外教教你学第十一讲成对词的顺序

Very manyidioms consist of pairs. Life has its ups and downs. He doesn't know whether he is comingorgoing. They came from the east and from the west.Reversing the order creates an unprofessional impression. For example, "life has its downs and ups,"or,"he doesn't know whether he is going or coming,"is obviously not how a native speaker would say it.……

外教教你学第十讲从句的主语

1.…ing clauses are usefulfor describing twosimultaneousactions.The actions can be past,present or future. ……

都柏林的童年

When I was nine years old there was nothing I loved more than being chased by grown ups. Nothing equaled the excitement of it. During the long summer holidays from school I went out the front door of our semi-detached two storey house, hoping to see some of my mates on the road outside. What did I see only our next door neighbour Mr Hickey high up on his ladder painting the frame of his bedroom window. Here, I thought,was a good chance of a chase because Mr Higgins's hot temper was known everywhere in the neighbourhood. Over the garden wall I climbed and stood at the foot of the ladder and started shaking it.……

埃迪·兰恩的父亲

Mr Lane, Eddie Lane's Dad, came out the door of the betting shop at the end of Davis Road. With long,slow steps he walked across Davis Road, across the car park outside the Cherry Tree pub, and in the door of the pub. It was a damp Saturday afternoon.……

生在都柏林--屋后的空地

At the back of our house was a triangular(三角形的)field. We called it ‘the back field’. On one side of the triangle there was an open lane running along the back gardens of the houses in Pearse's Road. On the other side was a rubber factory called Somerville Roberts. In the distance you could see the mountains of south County Dublin.……

GE公司GEVO柴油机的开发

美国GE公司运输分部开发了一种新型柴油机以满足下一阶段的排放和燃油经济性要求。该型发动机的开发始于1998年,其包括GE公司现有发动机的最佳特性以及新发动机技术的最新发展。它将首先应用于自2005年起新造的符合美国环保局2级排放标准的内燃机车。GEVO12缸发动机在1050 r/min下的标定功率达到3360 kW,这相当于原来的一台7FDL 16缸发动机所达到的功率水平。发动机的缸径为250 mm,行程为320 mm。这导致了采用约2 0 MPa的较保守的平均有效压力。美国机车的2级排放标准较之0级和1级排放标准在降低NOx和颗粒物质排放方面具有特殊要求。为了达到NOx排放标准而对现有发动机作进一步调整势必造成燃油经济性的巨大损失。为此,GE公司运输分部正通过开发一种新型发动机来满足2级排放标准要求,新型发动机将不仅能满足排放要求,而且在燃油经济性方面较之现有发动机亦将有较大改进。发动机的性能开发包括燃烧模拟、系统模拟和优化。应用统计学方法对燃油喷射系统进行了优化设计以保证高效和可靠的运行。涡轮增压器设计采用了先进的空气动力学和结构模拟以获得高的效率和安全性。单缸机和多缸机的性能试验进一步改进了燃烧系统。采用一个严格的可靠性设计(DFR)程序对每个系统和部件的可靠性进行了评估。通过将?

GE公司PowerHaul柴油机的开发

GE运输装备公司开发了一种新系列柴油机以接受轻型机车高功率、低重量和新排放要求的挑战。该系列柴油机的第一个成员为16缸机,该机在1500r/min下标定功率为2750kW。未来的机型包括一种标定功率为2060kW的12缸发动机,其用于船舶发电。PowerHaul发动机由成功的6系列Jenbacher气体燃料发动机演变而来。它保持了后者的强度,同时应用了最新的燃料喷射、涡轮增压和燃烧系统技术。高压共轨系统可以灵活地优化NOx排放与燃油消耗之间的折衷效果,同时使颗粒物的排放降至最低。发动机采用高压比、单级增压器供应空气以支持一种适度的Miller循环燃烧系统。利用一适度的Miller循环进气门关闭来保持涡轮增压器和一种传统的气门机构简单匹配,与此同时保持良好的加速和低功率性能。在一台单缸试验机上对燃烧过程进行了模拟与校准,以评估几种活塞头、气门定时、增压比和燃油喷嘴几何形状的组合效果。这使得只需制造一套多缸硬件并直接达到功率、排放和燃油消耗的目标。该16缸发动机已被证明达到欧盟EUIIIa排放标准。发动机的基本结构经过修改以与机车主发电机紧密配合,并驱动机车冷却系统所需的机油泵和冷却水泵。发动机弹性地安装在机车内,除了抵抗在机车应用中遇到的冲击负荷外,还可以减少振动传递。通过广泛的部件和发动机耐久性试验,整个发动机及其主要零部件已被证实可以用于机车运营。发动机允许超速10%,超载20%。此外,还对发动机做了一项特殊的负荷循环试验,以使其能够胜任高循环机车运营。16缸PowerHaul发动机的首次应用将是安装在为英国货运铁路公司提供的PH37ACmi型机车上。在轻型机车市场上,该发动机代表了功率、排放、牵引力和燃油消耗的新标准。