6. nothing (else) but  只不过, 除了…不…
Indeed, it is possible that electrons are make of nothing else but negative electricity.
的确，电子只是由负电荷构成的。
7. no…unless…  如果没有……就没有，除非……否则不……
No current will flow at any time unless there is a complete circuit.
任何时候，如果没有闭合回路，就没有电流流动。
8. nothing but 只能，除……外什么也不……
Early computers did nothing but compute : adding, subtracting, multiplying, and dividing.
早期的计算机只能做加减乘除运算。
 
 
翻译的基本方法 – 肯定与否定处理 Skills of Translation –affirm and negate 2
9. no……-less  没有……不
No machine can be made completely frictionless.
没有摩擦力作用的机器是造不出来的。
10. nothing un-  没有什么……不
There is nothing unexpected about it.
一切都在意料之中。
（没有什么不在意料之中。）
11. impossible but   不可能不
It is impossible but that rod will be longer under such big tension force.
杆件在这么大的拉力作用下不可能不被拉长。
 
翻译的基本方法 – 肯定与否定处理 Skills of Translation –affirm and negate 2
（七）意义否定
    有些英语句子，虽然在结构上或形式上是肯定句，但由于含有表示否定意义的一些词，因而使句子在意义上变成了各种类型的否定句。如介词without, 带有前缀un-或in-的形容词，带有后缀-less的形容词，连词until和but等都可以构成否定意义。
The slight amount of current flowing through the voltmeter may be ignored.
通过伏特计的微量电流是可以忽略不计的。
Another advantage of the absence of moving parts is that a transformer needs very little attention.
变压器没有运动部件的另一好处，在于它几乎不需要照看。
 
翻译的基本方法 – 肯定与否定处理 Skills of Translation –affirm and negate 2
The unit horsepower is independent of the cutting speed.
马力这个单位与切削速度无关。
It is necessary to prevent the follower from losing contact with the cam.
必须使随动件与凸轮不脱离接触。
This equation is far from being complicated.
这个方程式一点也不复杂。
We tried in vain to measure the voltage.
我们原想测量电压，但没测成。（in vain 徒然的）
The principle of echo-ranging is by no means new.
回声测距原理一点也不新奇。
 
机械工程专业英语文献阅读之八  Mechanism 2
Mechanisms may be categorized in several different ways to emphasize their similarities and differences. One such grouping divides mechanisms into planar, spherical, and spatial categories. All three groups have many things in common; the criterion which distinguishes the groups, however, is to be found in the characteristics of the motions of the links. 
 
机械工程专业英语文献阅读之八  Words Learning
emphasize  V 强调, 着重,  emphasis  n.强调, 重点
He emphasize that we should lay heavy stress on law and order.
他强调我们应把主要重点放在法律和秩序上。
You should laid a strong emphasis on the study of foreign languages. 
你应把主要重点放在学习外语上。
similarity   类似，相似，类似处
I think they have the similarity of childhood experiences.
我认为他们的童年经历很相似。
Two transducer have a similarity in out appearance but difference in inner structure.
两个变换器有着相似的外形，但内部结构却不同。
 
机械工程专业英语文献阅读之八  Words Learning
divide…into  分成, 分为, 除, 被除尽
Let’s divide this paper into three section.
让我们把这篇文章分为三个部分。
Three will not divide into seven.
三除不尽七。
criterion  标准, 准则, 规范
We must make a acceptance criterion for new products.
我们必须为新产品制定一个验收标准。
distinguishes  区别，辩别，判别
He can not distinguish between right and wrong now.
他现在不能辨别是非。
Can you distinguish between silk and rayon
你能分清丝稠和人造丝吗？
 
机械工程专业英语文献阅读之八  Mechanism 2
A planar mechanism is one in which all particles
describe plane curves in space and all these curves lie in parallel planes; i.e., the loci of all points are plane curves parallel to a single common plane. This characteristic makes it possible to represent the locus of any chosen point of a planar mechanism in its true size and shape on a single drawing or figure. The plane four-bar linkage, the plate cam and follower, and
the slider-crank mechanism are familiar examples of planar mechanisms. The vast majority of mechanisms in use today are planar.
 
机械工程专业英语文献阅读之八  Words Learning
lie in  位于，处于……状态，
Harbin lies in northeast of China.
哈尔滨位于中国的东北部。
parallel to  平行，平行的，平行面，平行线，类似的
There are two hundred kilometers that road run parallel to a railway.
那条公路和铁路平行延伸二百公里。
drawing  图，制图，视图
All detail drawings and a assembling drawing should be given.
应给出全部零件图和一张装配图。
familiar  熟悉(的), 常见的
I'm not familiar with her.
我同她不太熟悉。
 
机械工程专业英语文献阅读之八  Mechanism 2
A spherical mechanism is one in which each link has some point which remains stationary as the linkage moves and in which the stationary points of all links lie at a common location; i.e., the locus of each point is a curve contained in a
spherical surface, and the spherical surfaces defined by several arbitrarily chosen points are all concentric. The motions of all particles can therefore be completely described by their radial
projections, or "shadows," on the surface of a sphere with properly chosen center. Hooke's universal joint is perhaps the most familiar example of a spherical mechanism.
 
机械工程专业英语文献阅读之八  Words Learning
stationary  固定的, 静止的,不变的
All cars remained stationary as the snow was too heavy.
由于雪下得太大了，所有车子都停住不动了。
concentric  同心(轴)的
The input shaft of the gearing should be concentric with the output shaft of motor.
传动装置的输入轴应该与电机输入轴同轴。
projection  发射, 投影, 投影法
Geometric projection was introduced in cartography.
将几何投影法引入制图学。
universal  普遍的, 全体的, 通用的
War causes universal misery.
战争给所有的人带来苦难。
 
机械工程专业英语文献阅读之八  Mechanism 2
Spatial mechanisms, on the other hand, include no restrictions on the relative motions of the particles. The motion transformation is not necessarily coplanar, nor must it be concentric. A spatial mechanism may have particles with loci of double curvature. Any linkage which contains a screw pair, for example, is a spatial mechanism, since the relative motion within a screw pair is helical.
 
机械工程专业英语文献阅读之八  Words Learning
restrictions   限制, 约束
The productive capacity is the restriction of output products.
产量受生产能力的制约。
curvature   弯曲，曲率，曲度
Curvature radius of the cam is too small to gain a smooth motion of a follower.
凸轮的曲率半径太小了，从动件不能获得平稳的运动。
screw pair  螺旋副，
screw-jack fulfill the task of lifting a high weight object by the principle of screw pair.
螺旋千斤顶是利用螺旋副的原理来提升重物的。
helical  螺旋状的
A pair of helical bevel gears was used in transducer.
变速器中采用了一对螺旋伞齿轮。
 
机械工程专业英语   作业  English in  Mechanical Engineering (home work)
 


9机械工程专业英语  第九课
 
科技英语英文摘要简介 Abstract of English for Science and Technology
 
摘要与文摘:
    摘要与文摘两者在作用和结构方面是有
区别的。英文Abstract,在英汉词典里既作
“摘要”讲,也作“文摘”讲。
摘要
(1) 是一篇完整论文的一部分，但不是正文的部分。
(2) 它高度概括了正文叙述的内容，突出正文的重点, 是正文实质性内容的介绍。（读者通过阅读摘要，初步就能确定此文章对读者的重要性，究竟对读者从事的科研、教学有无参考价值，从而决定有否必要阅读正文。）
(3) 摘要虽然不是正文的一部分，但是它也不能脱离文章而单独印刷发行。
文摘
    文摘是一种能脱离正文而单独印行的科技文体，主要以文摘期刊或文摘卡片或光盘形式发行。文摘除向读者介绍有关的最新文献的主要内容外（有时是摘要），还介绍该文献的来源，以及查找全文的渠道。
世界上有很多著名的文摘机构
.科学引文索引 SCI （Science Citation Index）

.工程索引 EI （Engineering Index）

.科学技术会议索引 ISTP 


（Index to Scientific & Technical Proceedings）
 
英文摘要的内容
    英文摘要需要提供给读者一种信息，即
该篇文章所包含的主要概念和讨论的主要问
题。摘要主要可分为指示型、信息-指示型和
信息型3种。 
 
（一）指示性摘要
    指示型摘要（indicative abstract）即介绍型摘要，也称陈述型摘要。它只简要地介绍论
文的论题，或者概括地表述研究的目的，仅使
读者对论文的主要内容有一概括的了解。指示
型摘要一般不介绍方法、结果、结论的具体内