吃吃吃吃吃Chen
Six Sigma seeks to identify and remove the causes of defects and errors in manufacturing and business processes.[1] It uses a set of quality management methods, including statistical methods, and creates a special infrastructure of people within the organization ("Black Belts" etc.) who are experts in these methods.[1] Each Six Sigma project carried out within an organization follows a defined sequence of steps and has quantified financial targets Historical overview Six Sigma was originally developed as a set of practices designed to improve manufacturing processes and eliminate defects, but its application was subsequently extended to other types of business processes as well.[2] In Six Sigma, a defect is defined as anything that could lead to customer dissatisfaction.[1] The particulars of the methodology were first formulated by Bill Smith at Motorola in 1986.[3] Six Sigma was heavily inspired by six preceding decades of quality improvement methodologies such as quality control, TQM, and Zero Defects, based on the work of pioneers such as Shewhart, Deming, Juran, Ishikawa, Taguchi and others. Like its predecessors, Six Sigma asserts that – Continuous efforts to achieve stable and predictable process results (i.e. reduce process variation) are of vital importance to business success. Manufacturing and business processes have characteristics that can be measured, analyzed, improved and controlled. Achieving sustained quality improvement requires commitment from the entire organization, particularly from top-level management. Features that set Six Sigma apart from previous quality improvement initiatives include – A clear focus on achieving measurable and quantifiable financial returns from any Six Sigma project.[1] An increased emphasis on strong and passionate management leadership and support.[1] A special infrastructure of "Champions," "Master Black Belts," "Black Belts," etc. to lead and implement the Six Sigma approach.[1] A clear commitment to making decisions on the basis of verifiable data, rather than assumptions and guesswork.[1] The term "Six Sigma" is derived from a field of statistics known as process capability studies. Originally, it referred to the ability of manufacturing processes to produce a very high proportion of output within specification. Processes that operate with "six sigma quality" over the short term are assumed to produce long-term defect levels below 3.4 defects per million opportunities (DPMO).[4][5] Six Sigma's implicit goal is to improve all processes to that level of quality or better. Six Sigma is a registered service mark and trademark of Motorola, Inc.[6] Motorola has reported over US$17 billion in savings[7] from Six Sigma as of 2006. Other early adopters of Six Sigma who achieved well-publicized success include Honeywell (previously known as AlliedSignal) and General Electric, where the method was introduced by Jack Welch.[8] By the late 1990s, about two-thirds of the Fortune 500 organizations had begun Six Sigma initiatives with the aim of reducing costs and improving quality.[9] In recent years, Six Sigma has sometimes been combined with lean manufacturing to yield a methodology named Lean Six Sigma. [edit] Origin and meaning of the term "six sigma process" Graph of the normal distribution, which underlies the statistical assumptions of the Six Sigma model. The Greek letter σ marks the distance on the horizontal axis between the mean, µ, and the curve's inflection point. The greater this distance is, the greater is the spread of values encountered. For the curve shown in red above, µ = 0 and σ = 1. The other curves illustrate different values of µ and σ.Sigma (the lower-case Greek letter σ) is used to represent the standard deviation (a measure of variation) of a statistical population. The term "six sigma process" comes from the notion that if one has six standard deviations between the process mean and the nearest specification limit, there will be practically no items that fail to meet specifications.[5] This is based on the calculation method employed in process capability studies. In a capability study, the number of standard deviations between the process mean and the nearest specification limit is given in sigma units. As process standard deviation goes up, or the mean of the process moves away from the center of the tolerance, fewer standard deviations will fit between the mean and the nearest specification limit, decreasing the sigma number and increasing the likelihood of items outside specification.[5] [edit] Role of the 1.5 sigma shift Experience has shown that in the long term, processes usually do not perform as well as they do in the short.[5] As a result, the number of sigmas that will fit between the process mean and the nearest specification limit is likely to drop over time, compared to an initial short-term study.[5] To account for this real-life increase in process variation over time, an empirically-based 1.5 sigma shift is introduced into the calculation.[10][5] According to this idea, a process that fits six sigmas between the process mean and the nearest specification limit in a short-term study will in the long term only fit 4.5 sigmas – either because the process mean will move over time, or because the long-term standard deviation of the process will be greater than that observed in the short term, or both.[5] Hence the widely accepted definition of a six sigma process is one that produces 3.4 defective parts per million opportunities (DPMO). This is based on the fact that a process that is normally distributed will have 3.4 parts per million beyond a point that is 4.5 standard deviations above or below the mean (one-sided capability study).[5] So the 3.4 DPMO of a "Six Sigma" process in fact corresponds to 4.5 sigmas, namely 6 sigmas minus the 1.5 sigma shift introduced to account for long-term variation.[5] This is designed to prevent underestimation of the defect levels likely to be encountered in real-life operation.[5] [edit] Sigma levels See also: Three sigma rule Taking the 1.5 sigma shift into account, short-term sigma levels correspond to the following long-term DPMO values (one-sided): One Sigma = 690,000 DPMO = 68.26% efficiency Two Sigma = 308,000 DPMO = 95.24% efficiency Three Sigma = 66,800 DPMO = 99.73% efficiency Six Sigma = 3.4 DPMO = 99.9997% efficiency [edit] Methods Six Sigma has two key methods: DMAIC and DMADV, both inspired by Deming's Plan-Do-Check-Act Cycle.[9] DMAIC is used to improve an existing business process; DMADV is used to create new product or process designs.[9] [edit] DMAIC The basic method consists of the following five steps: Define high-level project goals and the current process. Measure key aspects of the current process and collect relevant data. Analyze the data to verify cause-and-effect relationships. Determine what the relationships are, and attempt to ensure that all factors have been considered. Improve or optimize the process based upon data analysis using techniques like Design of experiments. Control to ensure that any deviations from target are corrected before they result in defects. Set up pilot runs to establish process capability, move on to production, set up control mechanisms and continuously monitor the process. [edit] DMADV The basic method consists of the following five steps: Define design goals that are consistent with customer demands and the enterprise strategy. Measure and identify CTQs (characteristics that are Critical To Quality), product capabilities, production process capability, and risks. Analyze to develop and design alternatives, create a high-level design and evaluate design capability to select the best design. Design details, optimize the design, and plan for design verification. This phase may require simulations. Verify the design, set up pilot runs, implement the production process and hand it over to the process owners. DMADV is also known as DFSS, an abbreviation of "Design For Six Sigma".[9] [edit] Implementation roles One of the key innovations of Six Sigma is the professionalizing of quality management functions. Prior to Six Sigma, quality management in practice was largely relegated to the production floor and to statisticians in a separate quality department. Six Sigma borrows martial arts ranking terminology to define a hierarchy (and career path) that cuts across all business functions and a promotion path straight into the executive suite. Six Sigma identifies several key roles for its successful implementation.[11] Executive Leadership includes the CEO and other members of top management. They are responsible for setting up a vision for Six Sigma implementation. They also empower the other role holders with the freedom and resources to explore new ideas for breakthrough improvements. Champions are responsible for Six Sigma implementation across the organization in an integrated manner. The Executive Leadership draws them from upper management. Champions also act as mentors to Black Belts. Master Black Belts, identified by champions, act as in-house coaches on Six Sigma. They devote 100% of their time to Six Sigma. They assist champions and guide Black Belts and Green Belts. Apart from statistical tasks, their time is spent on ensuring consistent application of Six Sigma across various functions and departments. Black Belts operate under Master Black Belts to apply Six Sigma methodology to specific projects. They devote 100% of their time to Six Sigma. They primarily focus on Six Sigma project execution, whereas Champions and Master Black Belts focus on identifying projects/functions for Six Sigma.
天天~甜甜
1.引言景观设计是环境设计的组成部分,大到绵延几十公里的风景区规划,小到十几平方米的庭院设计,都属于景观设计的范畴。本文的景观设计定位于城市景观设计的层次上,选择城市景观设计作为切入点,从中研究分析一般的设计要素和方法,是比较适宜的。近年来,我们生活的城市发生了很大的变化,大批的广场绿地、商业步行街、主题公园、街头小品出现在我们的视觉以内,影响着我们的感观和行为方式。而新建的住宅小区都以景观优美的园林作为卖点,影响着人们的思维和购买心理。景观设计已经不知不觉中走到了我们的周围,走近了我们的身边,并对我们施展着潜移默化的作用。你可以不到美术馆去欣赏艺术品,但你不得不在城市环境中行走,不得不在居住小区的环境中活动,它的景观视觉美感、造型形态、色彩、材质、以及在阳光下灯光下呈现出来的效果,时时会刺激你的目光,影响你的行为和心理的变化。一个有良好景观的城市环境、居住环境,为人们提供了物质功能和精神功能双重价值。“诗意的栖居”始终是人们内心的向往,而景观设计正式通过提高生活品质,提升生活品位,以人为主体,以空间环境为客体,构架着现实通向理想的桥梁。2.景观的概念景观(Landscape),什么是景观,无论是在西方还是在东方,都是一个美丽而难以说清的概念。哪怕是同一景象,不同的人都有不同的理解。景观是人类的栖息地,景观是人类的工艺品,景观是需要科学分析方法能被理解的物质系统,景观是有待解决的问题,景观是可以带来财富的资源,景观是反映社会伦理、道德和价值观念的意识形态,景观是历史,景观是美。我们可以从景观与人的物我关系与景观的艺术性、科学性、场所性及符号性入手,来认识景观。2.1 景观的视觉美的含义:外在人眼中的景象景观作为城市景象景观的设计与创造,实际上也就是创造城市、造建筑的城市。景观作为视觉审美对象的含义,经历了一些微妙的变化。第一个变化来源于文艺复兴时期对乡村土地的贪欲,即景观作为城市的延伸;其二则来源于工业革命中后期对城市的恐惧和憎恶,即景观作为对工业城市的对抗。景观作为城市的延伸和附属 人们最早注意到的景观是城市本身,“景观的视野随后从城市扩展到了乡村,是乡村也成为景观”。文艺复兴之前的欧洲封建领主制度将人束缚在君权之下,人被束缚在土地之中,大自然充满神秘和恐怖,且又为人类生活之母,对土地的眷恋和依赖,使得人如母亲襁褓之中的婴儿。城市资本主义的兴起使人从土地中解放出来,土地的价值从生活和生存所必须的使用价值,转变成为可以交换的商品和资源,人与土地第一次分离而成为城里人。新兴的城市贵族通过强大的资本勾画其理想的城市,同时不断的向乡村扩展,将其作为城市的附属。1420年前后发明的ts原理,使理想城市的模式成为一个完全几何、数学的围有围墙的图案。在几何中心是一个大的开放空间,被行政建筑所包围:国王的宫殿,法院的大楼,主教堂,监狱,财务大楼和军事中心。这样的理想城市是为行政办公及法律公正而设立的,是为了城市生活而设计的,是纯粹理想化的。理想城市模式与文艺复兴时期的绘画一样,遵循了严格的比例关系和美学原则。而景观作为城市的延伸,也被同样的审美标准来设计和建造,因此有了凡尔塞为代表的巴洛克造园。景观作为城市的逃避 景观作为视觉美的含义的第二个转变,源于工业化带来的城市环境的恶化。工业化本身是文艺复兴的成果,但是至少从19世纪下半叶开始,在欧洲和美国各大城市,城市环境极度恶化。城市作为文明和高雅的形象被彻底破坏。相反成为了丑陋和恐怖的场所,而自然原野和田园成为了逃避的场所。因此。作为审美对象的景观也从欣赏和赞美城市,转向爱恋和保护田园。因此才有以Olmsted为代表的景观设计师的出现和景观设计学的诞生。一般来说,这个诞生的时间被确认为是1863年5月;因此才有以倡导田园风光为主调的美国城市公园运动,和以保护自然原始美景为主导的美国国家公园体系;因此也才有霍华德那深得人心的田园城市和随后的田园郊区运动。2.2 景观的栖息地含义:内在人的生活体验景观是人与人、人与自然关系在大地上的烙印 每一景观都是人类居住的家,或者说是潜在的家。中国古代山水画把可居性作为画境和意境的最高标准。所谓的“山水有可行者,有可望者,有可居者,有可游者……但可行可望不如可居可游之为得”(郭熙、郭思《林泉高致》)。无论是作画还是赏画,实质上都是一种卜居的过程。也就是场所概念(place)的深层含义。这便又回到哲学家海得歌尔的栖居概念。栖居的过程实际上与自然的力量与过程相互作用,以便取得和谐的过程,大地上的景观是人类为了生存和生活而对自然的适应、改造和创造的结果。同时,栖居的过程也是建立在人与人和谐相处的过程。因此,作为栖息地的景观,是人与人,人与自然关系在大地上的烙印。景观是内在人的生活体验 景观作为人在其中生活的地方,把具体的人和具体的场所联系在一起。景观是由场所构成的,而场所的结构又是通过景观来表达的。与时间和空间的概念一样,场所是无处不在的,人离不开场所,场所是人于地球和宇宙中的立足之处,场所使无变为有,使抽象变具体,是人在冥冥之中有了一个认识和把握外界空间和认识及定位自己的出发点和终点。2.3 景观作为系统的含义:科学、客观的解读在一个景观系统中,至少存在着五个层次以上的生态关系:第一是景观与外部系统的关系,如哈尼族村寨的核心生态流是水。哀劳山中,山有多高,水有多深,高海拔将南太平洋的暖湿气流截而为雨,在被灌溉,饮用和洗涤利用之后,流到干热的红河谷地,而后蒸腾、蒸发回大气,经降雨又回到本景观之中,从而有了经久不衰的元阳梯田和山上茂密的丛林,这是全球及区域生态系统科学研究的对象。根据Lovelock的盖娅理论,大地本来是一个生命体:地表、空气、海洋和地下水等通过各种生物的物理的和化学的过程,维持着一个生命的地球。第二是景观内部各个元素之间的生态关系,即水平生态过程。来自大气的雨、雾,经过村寨上丛林的截流、涵养,成为终年不断的涓涓细流,最先被引入寨中人所共饮的蓄水池;再流经家家户户门前的洗涤池,汇入寨中和寨边的池塘,那里是耕牛沐浴和养鱼的场所,最后富含养分的水流,被引入寨子下方的层层梯田,灌溉着他们的主要作物——水稻。这种水平生态过程,包括水流、物种流、营养流与景观空间格局的关系,正是景观生态学的主要研究对象。第三种生态关系,是景观元素内部的结构与功能的关系,如丛林作为一个森林生态系统,水塘作为一个水域生态系统,梯田本身作为一个农田系统,其内部结构与物质和能量流的关系,这是一种在系统边界明确情况下的垂直生态关系,其结构是食物链和营养阶,功能是物质循环和能量流动,这是生态系统生态学的研究对象。第四种生态关系则存在于生命和环境之间,包括植物与植物个体之间与群体之间的竞争、共生关系,是生物对环境的适应,及个体与群体的进化和演替过程,这便是植物生态、动物生态、个体生态、种群生态所研究的对象。第五种生态关系则存在于人类与其环境之间的物质、营养及能量的关系,这是人类生态学所要讨论的。当然,人类本身的复杂性,包括其社会、文化、政治性以及心理因素都使得人与人、人与自然的关系变得十分复杂。已远非人类生态本身所能解决,因此又必须借助社会学、文化生态、心理学、行为学等学科对景观进行研究。城市景观作为一个生态系统,几乎包含了所有上诉生态过程,而成为城市生态学的研究对象。2.4 景观作为符号的含义:人类理想和历史的书人类是符号动物,景观是一个符号传播的媒体,是有含义的,它记载着一个地方的历史,包括自然和社会历史;讲述着动人的故事,包括美丽的或者是凄惨的故事;讲述着土地的归属,也讲述着人与土地,人与人,以及人与社会的关系,因此行万里路,如读万卷书。这本书是由符号和语言写成的,“景观具有语言的所有特征,它包含着话语中的单词和构成——形状图案、结构、材料、形态和功能。所有景观都是由这些组成的。如同单词的含义一样,景观组成的含义是潜在的,只存在于上下文中才能显示。景观语言也有方言,它可以是实用的,也可以是诗意的。海得歌尔把语言比喻成人们栖居的房子。景观语言是人类最早的语言,是人类文字及数字语言的源泉。“河出图,洛出书”固然是一个神话传说,但它却生动的说明了中国文字与数字起源于对自然景观中自然物及现象的观察和启示的过程。同文字语言一样,景观语言可以用来说,读和书写,为了生存和生活——吃、住、行、求偶和生殖,人类发明了景观语言,如同文字语言一样,景观语言是社会的产物。景观语言是为了交流信息和情感的,同时也是为了庇护和隔离的,景观语言所表达的含义只能部分地为外来者所读懂,而有很大部分只能为自己族群的人所共享,从而在交流中维护了族群内部的认同,而有效的抵御外来者的攻击。景观中的基本名词是石头、水、植物、动物和人工构筑物,他们的形态、颜色、线条和质地是形容词和状语。这些元素在空间上的不同组合,便构成了句子、文章和充满意味的书。一本关于自然的书,关于这个地方的书,以及关于景观中人的书。当然,要读懂,读者就必须要有相应的知识和文化。不同的社会文化背景的人,如同上下文关系中的景观语言一样,是有多重含义的,这都是因为人是符号的动物;而景观符号,是人类文化和理想的载体。3.景观设计的概念景观设计是指通过对环境的设计使人与自然相互协调,和谐共存。她是大工业时代的产物、科学与艺术的结晶,融合了工程和艺术、自然与人文科学的精髓,创造一个高品质的生活居住环境,帮助人们塑造一种新的生活意识,更是社会发展的趋势。3.1 景观设计所涵盖的领域景观设计具有广泛的领域,大到国土与区域规划设计,小到庭院,甚至室内的绿色空间设计;从纯自然的生态保护和恢复,到城市中心地段的空间设计,都是景观设计多涵盖的领域。以下就初步的谈一下景观设计所涵盖的领域:3.1.1城镇规划景观设计师很早就开始担当城市物质空间的规划角色,城镇规划是城市空间的中心规划。城镇规划是针对城市与乡镇的规划与设计。规划者运用区域规划技术与法规、常规规划、概念规划、土地使用研究和其他方法来确定城市地域内的布局与组织。城镇规划也涉及到“城市设计”内容,如广场、街道景观等开放空间与公共空间的发展。3.1.2场地和社区规划环境设计是景观设计专业的核心问题。涉及到居住区、商业、工业、各机构的室内空间以及公共空间等室外空间的细部设计。它把场地作为艺术研究的对象来看待,综合平衡室内与室外的软、硬表面,建筑物与植物的材料选择以及灌溉、栽培等基础设施建设和详细的构筑物的规划说明与准备等。场地规划以某一地块内的建筑和自然元素的协调与安排为基础,场地规划项目涉及单幢建筑的土地设计、办公区公园设计、购物中心或整个居住社区的地块设计等。从更大的职业范围讲,基地设计还包括基地内自然元素与人工元素的秩序性、效率性、审美性以及生态等敏感性的组织与整合。其中,基地的自然环境包括地形、植物、水系、野生动物和气候。敏感性的设计有利于减少环境压力与消耗,从而提高基地的价值。(接下面!)
雪野在宁
Translation studies As we all know, translation means communication. It is important to our daily life. When we want to communicate with others, At first, We must translateone language into another. But, translation is a complex process. Because thereare many additional factors involved. If we wan t t o get a prefect result, we must master many skills. This paper talked about something about translation.I think if we pay more attention to the following details, we will do better in translation. While opening up new perspectives, the genegel approach as practiced in North American transition workshops might best be characterized by a theoretion and subjection that tend to reinforce whatever theoretical values individual translators hold .much that has been written on the subject of translation yields very little when sifed for theoretical substance because it has always been written as if spoken in the wortkshop . the personal anecdotes and pieces of advice may provide some help ,but certainly not the coherent and consistent theory required for translation. The problem is not just a contemporary phenomenon in North America ,but one that has troubled translation theory historically . people practiced translation ,but they were never quite sure what they were practicing. During the sixties in the United States ,the translation workshop perpetuated the same practice .Clearly, a more systematic approach to translation was needed ,and the discipline that appeared to have the theoretical and linguistic tools necessary to address the problem was linguistics .
烈香杜鹃7366
Diesel vehicles Diesel vehicles may be making a comeback. Diesel engines are more powerful and fuel-efficient than similar-sized gasoline engines (about 30-35% more fuel efficient). Plus, today's diesel vehicles are much improved over diesels of the past. 柴油车柴油车可能正在东山再起. 柴油引擎更强大,更省油,比同样大小的汽油发动机(约30-35%的燃油效率) . 再加上,今天的柴油车,大大改善了柴油机的过去. Better Performance Improved fuel injection and electronic engine control technologies have Increased power Improved acceleration Increased efficiency New engine designs, along with noise- and vibration-damping technologies, have made them quieter and smoother. Cold-weather starting has been improved also. 表现较好的改善燃料喷射和发动机电子控制技术的进步已增加力量加快改善效率,增加新的引擎设计, 随着噪声及减振技术,取得了他们的宁静和畅顺. 寒冷天气开始有所改善也. Cleaner Today's diesels must meet the same emissions standards as gasoline vehicles, and advances in engine technologies, ultra-low sulfur diesel fuel, and improved exhaust treatment have made this possible. Although emissions of particulates and smog-forming nitrogen oxides (NOx) are still relatively high, new "clean" diesel fuels, such as ultra-low sulfur diesel and biodiesel, and advances in emission control technologies will reduce these pollutants also. 今天清洁的柴油,必须符合相同的排放标准,汽油车,先进的引擎技术, 超低硫柴油,并改进尾气处理有这个可能. 虽然排放的悬浮粒子和烟雾形成的氮氧化物( NOX )仍比较高,新的"干净"的柴油燃料相比, 如超低含硫量柴油,生物柴油和垫款在排放控制技术,可减少这些污染物也. Hybrid-electric vehicles; Hybrid-electric vehicles (HEVs) combine the benefits of gasoline engines and electric motors and can be configured to obtain different objectives, such as improved fuel economy, increased power, or additional auxiliary power for electronic devices and power tools. Some of the advanced technologies typically used by hybrids include混合电动车; 混合动力电动汽车(的HEV )结合的好处,汽油发动机和电动马达,可以通过配置来获取不同的目标,这种 作为提高燃油经济性,提高动力,或额外的辅助电源的电子设备和电动工具. 一些先进的技术,通常用杂交种包括: Regenerative Braking. The electric motor applies resistance to the drivetrain causing the wheels to slow down. In return, the energy from the wheels turns the motor, which functions as a generator, converting energy normally wasted during coasting and braking into electricity, which is stored in a battery until needed by the electric motor. 再生制动. 电动机电阻适用于传动造成车轮放慢了. 作为回报,能量从车轮转动马达,它的功能是一台发电机, 能源转换通常浪费在滑行和刹车成电力, 这是储存在电池直到所需的电机. Electric Motor Drive/Assist. The electric motor provides additional power to assist the engine in accelerating, passing, or hill climbing. This allows a smaller, more efficient engine to be used. In some vehicles, the motor alone provides power for low-speed driving conditions where internal combustion engines are least efficient. 电机驱动/协助. 电动机提供额外的权力,以协助发动机在加速,超越,或爬山. 这使得规模较小,更加高效的引擎可以使用. 在一些车辆,电动机单独提供电源低速驾驶的情况下,内燃机是最有效的. Automatic Start/Shutoff. Automatically shuts off the engine when the vehicle comes to a stop and restarts it when the accelerator is pressed. This prevents wasted energy from idling. 自动启动/关机. 自动拒之门外引擎当汽车来停止并重新启动它时,油门被按下. 这样可避免浪费能源,从空转. Flexible fuel vehicles (FFVs) Flexible fuel vehicles (FFVs) are designed to run on gasoline or a blend of up to 85% ethanol (E85). Except for a few engine and fuel system modifications, they are identical to gasoline-only models. FFVs have been produced since the 1980s, and dozens of models are currently available. Since FFVs look just like gasoline-only models, you may have an FFV and not even know it. To determine if your vehicle is an FFV, check the inside of your car's fuel filler door for an identification sticker or consult your owner’s manual. 灵活燃料汽车(FFVs)灵活燃料汽车(FFVs) ,设计运行于汽油或混合最多 85%乙醇( e85 ) . 除了少数的发动机和燃油系统的改装,它们是相同的汽油只有模型. 灵活燃料汽车已累计生产80年代以来,几十种型号,目前可用. 自灵活燃料汽车很像汽油唯一模式,你可以有一个新鲜水果和蔬菜,甚至不知道它. 确定如果你的汽车是一个新鲜水果和蔬菜, 检查内你的车子的加油口门上一贴,鉴定或请教你的车主手册.FFVs experience no loss in performance when operating on E85. However, since a gallon of ethanol contains less energy than a gallon of gasoline, FFVs typically get about 20-30% fewer miles per gallon when fueled with E85. 灵活燃料汽车的经验,没有任何财物损失,在性能上经营e85 . 然而,由于一加仑乙醇含有更少的能源比一加仑汽油, 外国船队通常有约20-30%少英里每加仑,当燃用e85 . Electric vehicles (EVs) Electric vehicles (EVs) are propelled by an electric motor (or motors) powered by rechargeable battery packs. Electric motors have several advantages over internal combustion engines (ICEs): 电动车(电动车)电动车(电动车) ,发动机由电动机(或马达)提供动力的电池包. 电动马达拥有几项优势内燃机(考) : Energy efficient. Electric motors convert 75% of the chemical energy from the batteries to power the wheels—internal combustion engines (ICEs) only convert 20% of the energy stored in gasoline. Environmentally friendly. EVs emit no tailpipe pollutants, although the power plant producing the electricity may emit them. Electricity from nuclear-, hydro-, solar-, or wind-powered plants causes no air pollutants. 能源效率. 电动马达,将75%的化学能量从电池为电源的车轮-内燃机(考) ,只有转换 20%的能源储存汽油. 环保. 电动车不会排放废气污染物,虽然电厂生产的电力,排出的可能. 电力来自核,水能,太阳能,风能发电厂没有造成空气中的污染物. Reduce energy dependence. Electricity is a domestic energy source. Performance benefits. Electric motors provide quiet, smooth operation and stronger acceleration and require less maintenance than ICEs. The Down Side: Batteries 减少对能源的依赖. 电力是国内的能源来源. 性能优点. 电动马达提供安静,平稳操作和强大的加速度,需要的维修较少,比考. 弊:电池 EVs face significant battery-related challenges: Driving range. Most EVs can only go 150 miles (or less) before recharging—gasoline vehicles can go over 300 miles before refueling. Recharge time. Fully recharging the battery pack can take 4 to 8 hours. Battery cost: The large battery packs are expensive and usually must be replaced one or more times. Bulk & weight: Battery packs are heavy and take up considerable vehicle space. Researchers are working on improved battery technologies to increase driving range and decrease recharging time, replacement frequency, weight, and cost. These factors will ultimately determine the future of EVs. 电动车面临着电池相关的挑战:练习场. 大部分电动车只能走150英里(或更少) ,然后充电汽油车辆可走300英里,然后加油. 充电时间. 完全充电的电池包可以采取4至8小时. 电池成本:大型电池盒十分昂贵,通常必须更换1次或更多次. 体积及重量:电池包重,并采取了相当多的车辆空间. 研究人员正在改进电池技术,以增加练习场和减少充电时间,更换频率,重量和成本. 这些因素最终决定自己前途的电动车.
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