电气专业中英文翻译
The report concludes
The report mainly collected from the power transmission and power system requirements related to the content of these two
areas, and analyze, to understand some of the relevant knowledge.
Page2 Electrical Energy Transmission（电能输送）
1 English text
From reference 1
Growing populations and industrializing countries create huge needs for electrical energy. Unfortunately, electricity is not always
used in the same place that it is produced, meaning long-distance transmission lines and distribution systems are necessary. But
transmitting electricity over distance and via networks involves energy loss.
So, with growing demand comes the need to minimize this loss to achieve two main goals: reduce resource consumption while
delivering more power to users. Reducing consumption can be done in at least two ways: deliver electrical energy more efficiently
and change consumer habits.
Transmission and distribution of electrical energy require cables and power transformers, which create three types of energy loss:
the Joule effect, where energy is lost as heat in the conductor (a copper wire, for example); magnetic losses, where energy dissipates into a magnetic field;
the dielectric effect, where energy is absorbed in the insulating material.
The Joule effect in transmission cables accounts for losses of about 2.5 % while the losses in transformers range between 1 % and
2 % (depending on the type and ratings of the transformer). So, saving just 1 % on the electrical energy produced by a power
plant of 1 000 megawatts means transmitting 10 MW more to consumers, which is far from negligible: with the same energy we can
supply 1 000 - 2 000 more homes.
Changing consumer habits involves awareness-raising programmers, often undertaken by governments or activist groups. Simple
things, such as turning off lights in unoccupied rooms, or switching off the television at night (not just putting it into standby
mode), or setting tasks such as laundry for non-peak hours are but a few examples among the myriad of possibilities.
On the energy production side, building more efficient transmission and distribution systems is another way to go about it. High
efficiency transformers, superconducting transformers and high temperature superconductors are new technologies which promise
much in terms of electrical energy efficiency and at the same time, new techniques are being studied. These include direct current
and ultra high voltage transmission in both alternating current and direct current modes. Keywords: electrical energy transmission
From reference 2
Disturbing loads like arc furnaces and thyristor rectifiers draw fluctuating and harmonic currents from the utility grid. These non
sinusoidal currents cause a voltage drop across the finite internal grid impedance, and the voltage waveform in the vicinity becomes
distorted. Hence, the normal operation of sensitive consumers is jeopardized.
Active filters are a means to improve the power quality in distribution networks. In order to reduce the injection of non sinusoidal
load currents shunt active filters are connnected in parallel to disturbing loads (Fig. 1). The active filter investigated in this project
consists of a PWM controlled three-level VSI with a DC link capacitor.The VSI is connected to the point of common coupling via a
transformer. The configuration is identical with an advanced static var compensator.
The purpose of the active filter is to compensate transient and harmonic components of the load current so that only fundamental
frequency components remain in the grid current. Additionally, the active filter may provide the reactive power consumed by the
load. The control principle for the active filter is rather straightforward: The load current ismeasured, the fundamental active
component is removed from the measurement, and the result is used as the reference for the VSI output current.
In the low voltage grid, active filters may use inverters based on IGBTs with switching frequencies of 10 kHz or more. The harmonics
produced by those inverters are easily suppressed with small passive filters. The VSI can be regarded nearly as an ideally controllable
voltage source. Inmedium voltage applications with power ratings of several MV A, however, the switching frequen cy of today’s VSIs
is limited to some hundred Hertz. Modern high power IGCTs can operate at around 1 kHz. Therefore, large passive filters are needed
in order to remove the current ripple generated by the VSI. Furthermore, in fast control schemes the VSI no longer represents an
ideal voltage source because the PWM modulator produces a considerable dead-time. In this project a fast dead-beat algorithm for
PWM operated VSIs is developed [1].This algorithm improves the load current tracking performance and the stability of the active
filter. Normally, for a harmonics free current measurement the VSI current
would be sampled synchronously with the tips of the triangular carriers. Here, the current acquisition is shifted in order to minimize
the delays in the control loop. The harmonics now included in themeasurement can be calculated and subtracted from the VSI
current. Thus, an instantaneous current estimation free of harmonics is obtained.
Keywords: active filters
From reference 3
This report provides background information on electric power transmission and related policy issues. Proposals for changing federal
transmission policy before the 111th Congress include S. 539, the Clean Renewable Energy and Economic Development Act,
introduced on March 5, 2009; and the March 9, 2009, majority staff transmission siting draft of the Senate Energy and Natural
Resources Committee. The policy issues identified and discussed in this report include:
Federal Transmission Planning: several current proposals call for the federal government to sponsor and supervise large scale, on-
going transmission planning programs. Issues for Congress to consider are the objectives of the planning process (e.g., a focus on
supporting the development of renewable power or on a broader set of transmission goals), determining how much authority new
interconnection-wide planning entities should be granted, the degree to which transmission planning needs to consider non-
transmission solutions to power market needs, what resources the
executive agencies will need to oversee the planning process, and whether the benefits for projects included in the transmission
plans (e.g., a federal permitting option) will motivate developers to add unnecessary features and costs to qualify proposals for the
plan.
Permitting of Transmission Lines: a contentious issue is whether the federal government should assume from the states the primary
role in permitting new transmission lines. Related issues include whether Congress should view management and expansion of the
grid as primarily a state or national issue, whether national authority over grid reliability (which Congress established in the Energy
Policy Act of 2005) can be effectively exercised without federal authority over permitting, if it is important to accelerate the
construction of new transmission lines (which is one of the assumed benefits of federal permitting), and whether the executive
agencies are equipped to take on the task of permitting transmission lines.
Transmission Line Funding and Cost Allocation: the primary issues are whether the the federal government should help pay for new
transmission lines, and if Congress should establish a national standard for allocating the costs of interstate transmission lines to
ratepayers.
Transmission Modernization and the Smart Grid: issues include the need for Congressional oversight of existing federal smart grid
research, development, demonstration, and grant programs; and oversight over whether the smart grid is actually proving to be a
good investment for taxpayers and ratepayers.
Transmission System Reliability: it is not clear whether Congress and the executive branch have the information needed to evaluate
the reliability of the transmission system. Congress may also want to review whether the power industry is striking the right balance
between modernization and new construction as a means of enhancing transmission reliability, and whether the reliability standards
being developed for the transmission system are appropriate for a rapidly changing power system. Keywords: electric power transmission
Page3 Requirements of an Electric Supply System(供电系统需求)
1 English text
From reference1
Connections to external 330 kV power grids are provided using an open 330 kV switchyard. The plant is connected to the
Lithuanian power grid using two transmission lines L-454 and L-453, 330 kV each, to the Belorussian power grid using three
transmission lines L-450, L-452 and L-705, and to the Latvian power grid using one transmission line L-451.
Connections to external power grids at 110 kV are provided using the first section of the open 110 kV switchyard. The plant is
connected to the Lithuanian power grid using one transmission line “Zarasai” 110 kV, and to the Latvian power grid using one
transmission line L-632.
Connections between the open switchyards at 330 kV and 110 kV are established using two coupling autotransformers AT-1 and
AT-2, types ATDCTN- 200000/330. Power of each autotransformer is equal to 200 MV×A. The autotransformers have a device for
voltage regulation under load. The device type is RNOA-110/1000. 15 positions are provided to regulate voltage in a range (115 ±
6) kV.
The open 330 kV switchyard is designed using "4/3" principle (four circuit breakers per three connections) and consists of two
sections. Circuit breakers are placed in two rows. The first section of the open switchyard 110 kV is designed using “Double system
of buses with bypass” structure. The second section of open switchyard 110 kV is connected to the first section through two
circuit breakers C101 and C102. The second section has the same design as the first one. The following transmission lines are
connected to the second section: L-Vidzy, L-Opsa, L-Statyba, LDuk ?tas. These transmission lines are intended for district power
supplies, so they are not essential for electric power supply for the plant in-house operation.
Air circuit breakers of VNV-330/3150A type are used in the open 330 kV switchyard. Air circuit breakers of VVBK-110B-50/3150U1
type are used in open switchyard 110 kV. To supply power loads on voltage level 330 kV and 110 kV, aerial transmission lines are
used. Electrical connections of external grids 110 and 330 kV are presented in Fig. 8.1. Keywords: transmission lines
From reference 2
Abstract
This paper addresses sustainability criteria and the associated indicators allowing operationalization of the sustainability concept in the context of electricity supply. The criteria and indicators cover economic,
environmental and social aspects. Some selected results from environmental analysis, risk assessment and economic studies are
shown. These studies are supported by the extensive databases developed in this work. The applications of multi-criteria analysis
demonstrate the use of a framework that allows decision-makers to simultaneously address the often conflicting socio-economic and
ecological criteria. “EnergyGame”, the communication-oriented software recently developed by the Paul Scherrer Institute (PSI),
provides the opportunity to integrate the central knowledge-based results with subjective value judgments. In this way a sensitivity
map of technology choices can be constructed in an interactive manner. Accommodation of a range of perspectives expressed in
the energy debate, including the concept of sustainable development, may lead to different internal rankings of the options but
some patterns appear to be relatively robust.
Introduction
The public, opinion leaders and decision-makers ask for clear answers on issues concerning the energy sector and electricity
generation in particular. Is it feasible to phase out nuclear power in countries extensively relying on nuclear electricity supply and
simultaneously reduce greenhouse gas emissions? What are the environmental and economic implications of enhanced uses of
cogeneration systems, renewable sources and heat pumps? How do the various energy carriers compare with respect to accident
risks? How would internalization of external costs affect the relative competitiveness of the various means of electricity production?
What can we expect from the prospective technological advancements during the next two or three decades? Which systems or
energy mixes come closest to the ideal of being cheap, environmentally clean, reliable and at the same time exhibit low accident
risks?
How can we evaluate and rank the current and future energy supply options with respect to their performance on specific
sustainability criteria?
The Swiss GaBE Project on “Comprehensive Assessment of Energy Systems” provides answers to many issues in the Swiss and
international energy arena. A systematic, multidisciplinary, bottom-up methodology for the assessment of energy systems, has been
established and implemented. It covers environmental analysis, risk assessment and economic studies, which are supported by the
extensive databases developed in this work. One of the analysis products are aggregated indicators associated with the various
sustainability criteria, thus allowing a practical operationalization of the sustainability concept. Apart from technical and economic
aspects an integrated approach needs to consider also social preferences, which may be done in the framework of multi-criteria
analysis.
Keywords: criteria indicators
From reference 3
Mobility of persons and goods is an essential component of the competitiveness of European industry and services as well as an
essential citizen right. The goal of the EU's sustainable transport policy is to ensure that our transport systems meet society's
economic, social and environmental needs.
The transport sector is responsible for about 30% of the total final energy consumption and for about 25% of the total CO2
emissions. In particular the contribution of road transport is very high (around 80% and 70% respectively). These simple data shed
light on the necessity to move towards a more sustainable transportation system, but also suggest that a technological/systemic
revolution in the field will positively impact the overall world’s sustainable development.
From a technological point of view, a lower dependency from not renewable energy sources (i.e. fuel oil) of the road transport is
the main anticipated change. In particular electric engines possibly represent the natural vehicle evolution in this direction. Indeed
they have much higher energy efficiency (around three times that of internal combustion engines, ICE) and do not produce any
kind of tailpipe emissions. How the electricity will be supplied to the vehicles is still unpredictable due to the too many existing
uncertainties on the future development, but the electrification of the drive train will contribute to having alternative energy paths
to reduce the nearly total dependency on crude oil. In particular, vehicle range and performances allowed by the different
possibilities will play a key role on the debate.
At the moment a great attention is attracted by electric vehicles, both hybrid and not, that will allow users to recharge their
vehicles directly at home. This kind of vehicle can represent a real future alternative to the ICE vehicles in particular for what
concerns the daily commuting trips (whose range is quite low). It is therefore important to understand what might be the impact
on the electric supply system capabilities of this recharging activity.
In this light the present study carries out an analysis of this impact for the Province of Milan (of particular relevant due the very high
daily commuting trips) at a 2030 time horizon. Key issue of the analysis is the estimation of a potential market share evolution for the
electric vehicles. The results obtained show that even with a very high future market penetration the impact of the vehicles on the
annual energy consumption will be quite negligible. On the contrary they also show that without an appropriate regulation (e.g. the
intelligent integration of electric vehicles into the existing power grid as decentralised and flexible energy storage), they could
heavily impact on the daily electric power requirements.
Keywords: electric vehicles
报告总结
本次报告主要从网上收集了电能输送和供电系统的需求这两个方面的相关内容，并对其进行了分析，了解了一些相关知识。
2 中文翻译及分析
出资文献1：
人口增长和工业化国家导致电力能源的庞大需求量. 不幸的是, 电力的使用和生产常常不是在相同的地方，意味着长距离传输线路配电系统
是必需的. 然而长距离输电以及通过网络这就涉及到能量损耗的问题。.
所以，随着需求的增长，就要使得这个损耗最小化，以达到两个主要目标: 在减少资源消耗，同时为用户传送更多电能。至少有两种方式可
以实现减少消耗量：更有效地传送电能以及改变用户的习惯。
电能的传输和分配需要电缆和电力变压器, 他们产生三种类型的能量损失：焦耳效应, 那些在导体发热过程中损失的能量(例如铜金属线)；
电磁损耗, 这部分能量被转化为电磁场；电介质效应, 这部分能量在绝缘材料中被吸收。
传输电缆中的焦耳效应导致大约2.5 % 的损耗，电力变压器中这个损耗大约在1 %到 2 %之间(取决与变压器的类型和电压等级). 所以在
1000兆瓦的发电厂产出的电能中节省仅仅1%就意味着向用户传输了10 MW 能量，这是远不可忽视的：和它相同的能量，我们可以提供给
1 000 -
2 000个家庭。
改变消费习惯涉及到宣传计划，这常常由政府或积极团体进行。这仅是些简单的小事，例如关掉无人房间的灯，或在晚上关掉电视（不只
是把它进入待机模式），或把洗衣服安排在非高峰时段，这仅仅是无数的可行性中的几个例子。
在能源生产方面，建立更有效的传输和分配系统是减少损耗的另一种方式。高效变压器、超导变压器、高温超导体是能够保证电能效率的
新技术，同时我们要研究新的工艺。这包括交直流切换模式下的直流和特高压输电。
关键词：电能输送
出资文献2：
例如电弧炉和可控硅整流器这样的配电网负载会对公用电网产生扰动和谐波电流。这些非正弦电流导致有穷网络的内部阻抗电压下降，在
附近的电压波形产生畸变。因此，对电压敏感的用户的正常运作受到损害。
有源滤波器是一种手段，以提高配电网电能质量。为了减少注入的非正弦负荷电流，通过并联有源滤波器来重新分配负荷(图1)。有源滤波
器包括了PWM三级控制逆变器的直流环节的电容器。逆变器通过变压器进行公共连接，这样的配置等同于一种先进的静态变量补偿器
有源滤波器的目的是为了补偿瞬态和谐波分量负载电流的基本频率成分,所以只留在栅极电流。此外,有源滤波器可以提供无功功率被负荷。
控制原理,介绍了有源滤波器很简单:负载电流活性成分,将测量结果用作参考电压源逆变器输出电流。
在低电压电网,有源滤波器可以使用的基础上,IGBTs逆变器的开关频率10千赫或更多。那些产生的谐波的逆变器很容易抑制与小被动过滤器
。逆变器的几乎可以把被作为一种理想的可控的电压源等。然而，在几兆伏安电力级别的中压的应用中,如今的VSIs仅限于几百赫兹。现代
高功率IGCTs可以操作的大约1千赫兹。因此,需要大规模无源滤波器,以清除脉动电流产生。逆变器的。此外,在快速控制方案不再逆变器的代表一个理想的电压源PWM调制生产因为dead-time相当大。在这个项目dead-beat算法快
速发展VSIs PWM操作[1]该算法提高了跟踪性能和负载电流稳定的有源滤波器。通常,一个自由的谐波电流测量逆变电流。
将被采样时同步的三角形尖端的载体。在这里,当前的收购是为了最大限度地减少了控制回路的延迟。现在谐波的包括时能计算和衰减逆变
电流。因此,可以估计出摆脱了谐波的瞬时电流。
关键词：滤波
出资文献3：
该报告提供了背景资料的电力传输和相关的政策问题。改变政策建议111届前联邦传输539 .国会,包括清洁的可再生能源和经济开发条例,
介绍了2009年3月5日,2009年3月9日,多数员工传输选址参议院的草案能源和自然资源委员会。确定的政策问题,讨论了这份报告包括:
联邦传输计划:几个前沿建议呼吁联邦政府制定并监督大的规模,持续的传输规划中。国会的问题的目标是需要考虑的规划过程(例如,作出了
重点扶持的可再生能源的发展上,或者在一个更广泛的套传动目标),决定新多的权力广泛关联规划实体应该被授予,传输计划的程度,需要考虑
无输送解决电力市场的需要,有哪些资源
执行机构需要检查计划的过程中,是否在项目包括福利传动方案(比如,一个联邦允许选择)鼓励开发者增加不必要的特点、成本晋级提案的计
划。
允许的输电线路:一个有争议的话题是美国联邦政府是否从美国应当承担的主要角色,来允许新的输送线。相关问题,包括国会是否要看管理
和扩展栅格里,主要是一个国家或民族问题,是否在国家权威机构的电力输送网的可靠度(国会成立能源政策法案的2005)可以有效地执行联
邦权威没有在允许的情况下,如果它是很重要的,加快建设新的输电线路(假定的好处之一),联邦政府的允许是否有执行机构的任务,以允许输
电线路。
传输线的资金和成本分摊:主要问题是否有联邦政府将帮助支付新的传输线,如果国会不应确立一个全国范围的成本分配标准地方纳税人输电
线路对号州际公路。
传输现代化和聪明的网格:课题包含需要国会忽略了现有的联邦聪明的网格研究、发展、示范,并给予和监管程序;实际上是聪明阀是否证明
自己是一个不错的投资纳税人和地方纳税人。
传动系统可靠性:不清楚国会和行政部门有所需的信息的可靠性进行了评价的传输系统。国会也可能要检讨电力行业是否之间找到平衡点现
代化建设、新建设作为一种手段,提高传输的可靠性,以及处理可靠性的标准被开发出来用于传动系统适合一个快速变化的电力系统。
关键词：电能输送
2 中文翻译及分析
出资文献1：
连接到外部330千伏电网使用一个公开的330千伏提供送变电。植物被连接到立陶宛电网输电线路使用两L-454和L-453,需要330名千伏各电
网的使用三输电线路,L-450 L-452和L-705,拉脱维亚电网输电线路L-451使用。
连接到外部力量,提供110千伏网格使用第一部分开放的110千伏送变电。植物被连接到立陶宛电网输电线路使用110千伏和拉脱维亚电网输
电线路L-632使用。
打开开关之间的连结在330千伏及110千伏建立了耦合自耦变压器AT-1使用两AT-2、类型ATDCTN,——200000/330。能对各自耦变压器
等于200 MV。自耦变压器有一个装置的在荷载作用下,电压调整。是该设备类型RNOA-110/1000。15个新职位提供给调节电压范围(115±
6)千伏。
开放330千伏送变电设计使用“4/3”的原则(4断路器每三连接),由两个部分。断路器被安置在两排。第一部分开放送变电110千伏使用“双系
统设计的公车搭桥”的结构。第二部分开放送变电110千伏被连接到第一部分通过两个断路器C101和C102。第二部分有相同的设计的第一
次。下面的输电线路连接到第二条L-Vidzy,L-Opsa L-Statyba,以LDuk,。这些输电线路的目的是为地区电力供应,所以他们不是必需的电力供
应植物内部运作。
空气断路器的类型VNV-330/3150A用于开放330千伏送变电。空气断路器的使用VVBK-110B-50/3150U1类型在公开送变电110千伏。提供
电力负载电压水平330千伏及110千伏、空中输电线路使用。电气连接外部网格110、330千伏了图8.1。
关键词：输电线
出资文献2
文摘
本文对可持续发展的标准和相关的指标允许可持续发展概念的操作化语境中的供电。标准和指标覆盖经济效益、环境效益和社会方面。一
些选定的结果,从环境分析、风险评估和经济研究显示。这些研究受到广泛的数据库支持了这项工作。多准则的应用分析证明使用一种框架,
允许决策者往往都各不相让同时解决经济发展与生态标准。“EnergyGame”,通信-定向保罗最近开发的软件Scherrer研究所(PSI),提供机会整
合中央知识结果与主观价值判断。该方法灵敏度的地图可以构建技术选择以交互的态度。住宿表达了不同的观点在能源的辩论,包括可持续
发展的理念,可能会导致不同的内部挤一些模式的选择,但似乎相对鲁棒性。
介绍：
公众舆论领袖和决策者要求明确的答复能源部门有关问题和发电具体的目标。是可行的逐步淘汰核电广泛的国家依靠核电力供应同时减少
温室气体的排放吗?什么是环境与经济意涵热电联产系统的使用增强的、可再生的资源和热泵好吗?我们应该怎样利用不同的能源输送比较
就事故风险吗?额外成本内部化会如何影响相对竞争力的各种方式的电力生产方式吗?我们能期待从高职在技术上的进步下二或三十年?混合
制度或能源的最接近理想的被便宜, 干净整洁的,可靠的,同时具有低事故风险吗?我们怎样才能进行了综合评价和排位当前和未来能源供给
的选择对他们的表现在特定的可持续发展标准吗?瑞士费拉里”的综合评价项目能量系统”,提供一些瑞士和较多问题国际能源的舞台。一个系
统、多学科方法论,自下而上的评价能源系统,已经建立和实施。它涵盖环境分析、风险评估和经济研究,重点扶持广泛的数据库开发这项工
作。分析产品的相关聚集指标与不同的可持续发展,从而使一种实用标准的操作化可持续发展的概念。除了技术、经济等方面的综合方案也
需要考虑社会偏好,它可以做多的框架分析。
关键词：标准准则
出资文献3
流动的人员,货物是一个重要的组成部分,欧盟工业的竞争力、服务是一种基本的公民权利。目标欧盟的可持续交通政策是为了保证本港的交
通运输体系满足社会的经济、社会、环境的需要。
运输领域,负责大约30%的总最后能源消费和大约25%全部的二氧化碳的排放。特别是道路运输的贡献非常高(大约80%分别和70%)。这
些简单的数据说明了必要移到一个更可持续交通系统,而且反映出技术、系统革命积极影响和领域的整体世界的可持续发展。
技术的观点认为,较低的依赖从没有可再生能源(即燃料油)道路运输是主要预期变化。特别是很可能是表示电气引擎的自然车辆进化朝这个
方向。实际上,它们的确具有更高的能源效率(约的三倍,内燃机、冰)和不产生任何类型的排气管排放。如何将被提交给电车辆仍然难料由于
太多的未来发展存在的不确定性,但电气化驱动器列车将有助于有可替代能源的路径,以减少差不多完全对原油的依赖。特别是,车辆所允许
的范围和表现不同的可能性将扮演一个重要角色这些争论。
现在就被的重视都电动车,油电混合车,允许用户不知道给他们的交通工具直接在家里。这类汽车可以代表一个美好的未来替代方案特别是为
内燃机汽车旅行的日常通勤关心的是什么(其范围很低)。因此,重要的是,去了解可能的影响的电力供应系统能力充电的活动。
在这样的观点下目前的研究进行了分析影响的特定的米兰(省的有关由于很高的日常通勤到2030年时间旅行)地平线。关键问题的估计的分
析提出了潜在的市场份额的电动汽车的进化。计算结果表明,甚至到较高的市场渗透率的影响未来车辆在一年一度的能耗将会十分可以忽略
不计。相反他们还指出,没有一个适度规制(例如。智能集成的电动车加入现有的电网作为分权型和灵活的能源储备),他们可能会严重影响日
常电力需求。
电气工程及其自动化专业英语(1)重点
电气工程及其自动化专业英语 考试题型：选择10*2 单词翻译10*2 短句翻译5*4 长句翻译4*10 Exercise All the simple circuit elements that will be 在下面进行的工作中我们要研究的简单电路元件,可以根据流过元件的电流与元件两端的电压的关系进行分类。例如，如果元件两端的电压正比于流过元件的电流，即u＝ki，我们就把元件称为电阻器。其他的类型的简单电路元件的端电压正比于电流对时间的导数或正比于电流关于时间的积分。还有一些元件的电压完全独立于电流或电流完全独立于电压，这些是独立源。此外，我们还要定义一些特殊类型的电源，这些电源的电压或电流取决于电路中其他的电流或电压，这样的电源将被称为非独立源或受控源。 It must be emphasized that the linear 必须强调的是线性电阻器是一个理想的电路元件；它是物理元件的数学模型。我们可以很容易地买到或制造电阻器，但很快我们发现这种物理元件只有当电流、电压或者功率处于特定范围时其电压——电流之比才是恒定的，并且这个比值也取决于温度以及其它环境因素。我们通常应当把线性电阻器仅仅称为电阻器。只有当需要强调元件性质的时候才使用更长的形式称呼它。而对于任何非线性电阻器我们应当始终这么称呼它，非线性电阻器不应当必然地被视为不需要的元件。 If a circuit has two or more independent 如果一个电路有两个或多个独立源，求出具体变量值（电流或电压）的一种方法是使用节点分析法或网孔分析法。另一种方法是求出每个独立源对变量的作用然后把它们进行叠加。而这种方法被称为叠加法。叠加法原理表明线性电路某个元件两端的电压（或流过元件的电流）等于每个独立源单独作用时该元件两端的电压（或流过元件的电流）的代数和。 The ratio of the phase voltage to the 相电压与相电流之比等于电路的阻抗，符号为字母Z，阻抗是一个具有量纲为欧姆的复数量。阻抗不是一个相量，因此不能通过把它乘以e jωt,并取其实部把它转换成时域形式。但是，我们把电感器看作是通过其电感量L表现为时域形式而通过其阻抗jωL表现为频域形式，电容在时域里为电容量C而在频域里为1/jωc，阻抗是某种程度 上的频域变量而非时域变量。 Both wye and delta source connections 无论是星型连接的电源还是三角形连接的电源都有重要的实际应用意义。星型连接的电源用于长距离电力传输，此时电阻损耗(I2R)将达到最小。这是由于星型连接的线电压是三角形连接的线电压的√3倍，于是,对于相同的功率来说，三角型连接的线电流是星形连接的线电流的√3倍。三角形连接的电源使用在根据三相电源而需要的三个单相电路中。这种从三相到单相的转变用在住宅布线中因为家用照明和设备使用单相电源。三相电源用在需要大功率的工业布线中。在某些应用场合，无论负载是星形连接还是三角形连接并不重要。
各专业的英文翻译
哲学Philosophy 马克思主义哲学Philosophy of Marxism 中国哲学Chinese Philosophy 外国哲学Foreign Philosophies 逻辑学Logic 伦理学Ethics 美学Aesthetics 宗教学Science of Religion 科学技术哲学Philosophy of Science and Technology 经济学Economics 理论经济学Theoretical Economics 政治经济学Political Economy 经济思想史History of Economic Thought 经济史History of Economic 西方经济学Western Economics 世界经济World Economics 人口、资源与环境经济学Population, Resources and Environmental Economics 应用经济学Applied Economics 国民经济学National Economics 区域经济学Regional Economics 财政学（含税收学）Public Finance (including Taxation) 金融学（含保险学）Finance (including Insurance) 产业经济学Industrial Economics 国际贸易学International Trade 劳动经济学Labor Economics 统计学Statistics 数量经济学Quantitative Economics 中文学科、专业名称英文学科、专业名称 国防经济学National Defense Economics 法学Law 法学Science of Law 法学理论Jurisprudence 法律史Legal History 宪法学与行政法学Constitutional Law and Administrative Law 刑法学Criminal Jurisprudence 民商法学(含劳动法学、社会保障法学) Civil Law and Commercial Law (including Science of Labour Law and Science of Social Security Law ) 诉讼法学Science of Procedure Laws
电气英语翻译
Heat sink 散热器 Forward conduction 正向导通 Thyristor 晶闸管 Solid-state power device 固态功率器件 Silicon wafer 硅片，硅晶片 Self-latching 自锁 电流额定值current rating 反向击穿电压reverse breakdown voltage 负电流脉冲negative current pulse 交流电动机相位控制phase control AC motor 反向并联二极管reverse shunting diode 正信号positive signal Gate-turn-off thyristors 可关断晶闸管 固态功率器件基础 2.1 引言 在这一章中我们重点讨论固态功率器件，并且只讨论它们在相位控制或频率控制的三相460V交流鼠笼式感应电动机的应用。 2.2 固态功率器件 应用于固态交流电动机控制的功率半导体主要的五个类型如下： （1）二极管 （2）晶闸管（例如：硅控整流器SCRs） （3）（电子）晶体管 （4）可关断晶闸管 （5）双向可控硅 硅控整流器和双向可控硅通常用于相位控制。各种各样的二极管制品、硅控整流器、电子晶体管和可开断晶体管都应用于速度控制。这些器件的共性是：利用硅晶体薄片层层堆叠构成PN结的各种组合。在二极管、硅控整流器和可关断晶闸管中，P结常被叫作阳极，N结常被叫做阴极，在电子晶体管中相应的被叫做集电极和发射极。这些器件的区别在于导通和关断的方法及电流和电压的容量。 让我们来简答看一下这些器件，了解一下他们的参数。 2.2.1 二极管 图2.1是一个二极管。左边是一个中间有硅晶片的PN结，右边是单个二极管的表示符号。当阳极为正阴极为负时，会有电流通过，二极管本身伴随着一个比较小的压降。当极性相反时，只有很小的反向漏电流通过，这在图2.2中有表现出来。正向压降一般是1V左右，与电流额定值无关。 （PN结阳极阴极单个二极管PN结和表示符号） 二极管的正向电流额定值取决于起大小和设计，而这二者是根据器件的散热要求来确定的，一保证掐进不超过最大结温（通常是200℃）。 反向击穿电压（见图2.2）是二极管的另一个重要参数，它的数值较二极管尺寸大小更多地取决于其内部设计。
电子专业中英文翻译
基于单片机控制的光收发器设计 1 引言 在“三网合一”的推动下,光纤到户等光纤接入方案的应用日益广泛。在光进铜退的呼声下,光网络迅速发展。光收发器在光通信中起到光电、电光转换的作用，是光通信必不可少的器件。由于涉及到高速电路设计、精密机械加工和光学设计,光收发器的成本占据了光纤通信系统和的重要部分,而较高的光收发器价格成了制约光纤接入推广的瓶颈。进一步降低光收发器的成本将有利于光接入的应用推广，加快光进铜退的步伐。 光收发器主要由电路部分、光发送组件和光接收组件组成。其中电路部分又包括激光驱动、光接收信号放大和控制部分。目前市场上的光收发器的电路部分使用的是三个专用芯片。一直有公司在研究把激光驱动和接收信号放大电路集成在一个器件上,控制器使用普通的嵌入式处理器的方案。由于只使用一个专用芯片和一个通用芯片，这样就可以大幅降低电路部分的成本。ＰHYWORＫS 公司研制的PＨＹ1０76芯片就是一款这样的芯片。它主要针对1.２５Ｇｂpｓ到２.5Ｇbps的光收发器,具有外围电路简单，控制电路只需要普通的8位单片机就可以实现的特点。本文主要研究了PHY１076 的性能，选择了ATMEL 公司的ATＭEＧA88 单片机进行控制,设计出光收发器样品，并进行了性能测试,最终成功设计了1.25G 光收发器。 ２光收发器设计方案及工作原理讨论 光收发器在发展的过程中,有许多种不同的外形封装。ＳＦＰ(小型化可热插拔光收发一体模块）是目前在5Ｇｂpｓ以下速率中最先进的一种封装形式,具有小型化、可热插拔、功耗小、系统可集成度高以及能够进行数字诊断功能等特点。 本设计中使用激光驱动电路和光接收放大电路集成的PHY１076 作为专用芯片，使用ＡＴＭEL 的AVR 单片机ATＭEGA88 进行控制和实现DDＭ功能,加上相应的TOＳA(光发射组件）,ROSA(光接收组件)和结构件，设计了一款工作在1.25Gｂpｓ传输距离为10km 的ＳFP 光收发器。系统方框图如图1所示：
电气英文文献+翻译
POWER SUPPLY AND DISTRIBUTION SYSTEM ABSTRACT The basic function of the electric power system is to transport the electric power towards customers. The l0kV electric distribution net is a key point that connects the power supply with the electricity using on the industry, business and daily-life. For the electric power, allcostumers expect to pay the lowest price for the highest reliability, but don't consider that it's self-contradictory in the co-existence of economy and reliable.To improve the reliability of the power supply network, we must increase the investment cost of the network construction But, if the cost that improve the reliability of the network construction, but the investment on this kind of construction would be worthless if the reducing loss is on the power-off is less than the increasing investment on improving the reliability .Thus we find out a balance point to make the most economic,between the investment and the loss by calculating the investment on power net and the loss brought from power-off. KEYWARDS：power supply and distribution,power distribution reliability，reactive compensation,load distribution
各专业的英文翻译
中国教育在线考研频道提供考研全方面信息指导及咨询服务，为您成功考研提供一切帮助。 哲学Philosophy 马克思主义哲学Philosophy of Marxism 中国哲学Chinese Philosophy 外国哲学Foreign Philosophies 逻辑学Logic 伦理学Ethics 美学Aesthetics 宗教学Science of Religion 科学技术哲学Philosophy of Science and Technology 经济学Economics 理论经济学Theoretical Economics 政治经济学Political Economy 经济思想史History of Economic Thought 经济史History of Economic 西方经济学Western Economics 世界经济World Economics 人口、资源与环境经济学Population, Resources and Environmental Economics 应用经济学Applied Economics 国民经济学National Economics 区域经济学Regional Economics 财政学（含税收学）Public Finance (including Taxation) 金融学（含保险学）Finance (including Insurance) 产业经济学Industrial Economics 国际贸易学International Trade 劳动经济学Labor Economics 统计学Statistics 数量经济学Quantitative Economics 中文学科、专业名称英文学科、专业名称 国防经济学National Defense Economics 法学Law 法学Science of Law 法学理论Jurisprudence 法律史Legal History 宪法学与行政法学Constitutional Law and Administrative Law 刑法学Criminal Jurisprudence
电气专业英语翻译
Foundation of PLC 1. The central processing unit Although referred to as the brain of the system, the Central Processing Unit in a normal installation is the unsung hero, buried in a control cabinet, all but forgotten. 2. Basic Functionality In a programmable controller system, the central processing unit(CPU) provides both the heart and the brain required for successful and timely control execution. It rapidly and efficiently scans all of the system inputs, examines and solves the application logic, and updates all of the system outputs. In addition, it also gives itself a checkup each scan to ensure that its structure is still intact. In this chapter we will examine the central processing unit as it relates to the entire system. Included will be the various functional blocks in the CPU, typical scan techniques, I/O interface and memory users, power supplies, and system diagnostics. 3. Typical Function Block Interactions In practice, the central processing unit can vary in its architecture, but consists of the basic building block structure illustrated in Fig.1.1.The processing section consists of one or more microprocessors and their associated circuitry. While it is true that some of the luxury of using microprocessors, most modern systems use either a single microprocessors such as the AMD 2903, usedin a bit slice architecture. This multiple microprocessor system to break the control system tasks into many small components which can be executed in parallel. The result of this approach is to achieve execution speeds that are orders of magnitude faster than their single-tasking counterparts. In addition to efficiently processing direct I/O control information and being programmable, the real advantage that microprocessor-based system have over their hardwired relay counterparts is the ability to acquire and manipulate numerical data easily. It is this attribute that makes programmable controllers the powerhouses that they are today in solving tough factory automation problems. The factory of tomorrow will run efficiently only if quality information about process needs and status of the process equipment are known on a realtimes basis. This can and will come about only if the unit level controllers, including programmable controllers, are empowered with the ability to collect, analyze, concentrate, and deliver data about the process. As the
电气专业术语中英对照
一．电气名词Electric items 二．线路（母线、回路）Lines (Bus , circuits) 三．设备Equipments 四．保护、继电器Protection , relays 五．电气仪表Electric instruments 六．防雷Lightning protection 七．接地Grounding , earthing 八．室、所Room , Substation 九．电修车间设备Equipments of electric repair 十．材料Material 十一．图名Drawings , diagrams 十二．表头Tables 十三．标准图词汇Terms from standard DWG 一．电气名词Electric items 交（直）流Alternating (direct) current 短路电流Short-circuit current 起始次暂态短路电流Initial subtransient short-circuit current 冲击电流Impulse current 稳态短路电流Steady state short-circuit current 临界电流Critical current 切断电流Rupturing current 熔断电流Blow-out current 故障电流Fault current 计算电流Calculating current 极限有限电流Limit effective current 过电流Over current 逆电流Inverse current 整定电流Setting current 额定电流Rated current 电流密度Current density 短路电流最大有效值Maximum effective value of short-circuit current 高压High-voltage , High-tension 低压Low-voltage , Low-tension 计算电压Calculating voltage 激磁电压Exciting voltage 冲击电压Impulse voltage 临界电压Critical voltage
机械专业外文翻译中英文翻译
外文翻译 英文原文 Belt Conveying Systems Development of driving system Among the methods of material conveying employed，belt conveyors play a very important part in the reliable carrying of material over long distances at competitive cost．Conveyor systems have become larger and more complex and drive systems have also been going through a process of evolution and will continue to do so．Nowadays，bigger belts require more power and have brought the need for larger individual drives as well as multiple drives such as 3 drives of 750 kW for one belt(this is the case for the conveyor drives in Chengzhuang Mine)．The ability to control drive acceleration torque is critical to belt conveyors’ performance．An efficient drive system should be able to provide smooth，soft starts while maintaining belt tensions within the specified safe limits．For load sharing on multiple drives．torque and speed control are also important consideratio ns in the drive system’s design. Due to the advances in conveyor drive control technology，at present many more reliable．Cost-effective and performance-driven conveyor drive systems cov ering a wide range of power are available for customers’ choices[1]. 1 Analysis on conveyor drive technologies 1．1 Direct drives Full-voltage starters．With a full-voltage starter design，the conveyor head shaft is direct-coupled to the motor through the gear drive．Direct full-voltage starters are adequate for relatively low-power, simple-profile conveyors．With direct fu11-voltage starters．no control is provided for various conveyor loads and．depending on the ratio between fu11- and no-1oad power requirements，empty starting times can be three or four times faster than full load．The maintenance-free starting system is simple，low-cost and very reliable．However, they cannot control starting torque and maximum stall torque；therefore．they are
建筑电气英文翻译
建筑电气 电气工程设计包括两个主要的设计方面。主要是一部分的电能的转换及分配和电力的供配、照明系统、防雷接地系统。一般来说,建筑主要的变化包括:高压和低压配电系统、变压器、备用电源系统。电力系统包括配电和控制，室内和室外照明系统包括所有类型的照明，防雷系统包括入侵波防护、闪电传感器、接地、等电位连接和局部等电位连接等。辅助等电位连接等。在短短的20年里,系统在技术和产品的面貌发生了翻天覆地的变化。许多的设计理念也发生了巨大的变化。开关设备如高压系统的第一个断路器油断路器，后来油断路器的逐步发展,不仅规模大,但是一般都包含油物质。由于开关设备尺寸较大,我们还必须建立独立的设备房间,占据了大量的建筑面积。现在真空断路器和六氟化硫断路器,不仅体积小,而且短路容量大，外壳尺寸远小于原来的橱柜，并且断路器没有任何油,防火性能大大提高。而且断路器和其他低压设备在一个房间里,这样即节省空间又方便管理。过去大容量的低压断路器,短路电流容量逐渐变大,规模也逐渐变小,而且更加稳定,使系统运行更加安全可靠,为设计带来了方便。向着智能化低压断路器方向发展,断路器各种参数可以通过总线工业控制,信号直接传输到计算机。 干式变压器的出现,对建筑电气设计带来了极大的方便,因为没有变压器油泄漏和火灾的可能性,以便它可以很容易地安装在建筑本身,甚至直接到负荷中心。它还消除变压器对油的需求限制,构建大容量设备时可以使用干式变压器。在实际工程设计中曾应用四个台湾2500kVA干式变压器。 在使用紧急发电机方面,从性能和尺寸的角度来看,比过去进步很多。除了使用柴油发电机；应急照明使用EPS备用电源；中断供电在一个毫秒以内的设备,可以使用UPS。 电力设备的控制从单一元件的控制到控制继电器控制变化。除了更好的性能的各种组件的规模较小,也降低控制箱的规模。由于数字技术更多的运用于控制能达到最佳的控制状态来控制设备。进一步提高了节能的效果。 照明系统从过去单一光源、灯具和低效率的状态向更广泛的前景发展。建筑中使用的光源可供选择的品种数量很多。光的发光效率和色调在向着高效的方向发展,灯具不断地改进其效率和不同形式的灯具运用于不同场合。例如,普通的荧光灯镇流器由普通的镇流器向节能型镇流器方向发展。还对谐波组件的大小进行精简,生产低谐波电子镇流器。许多措施如配件和灯具的使用,可以满足设计要求,同时能实现不同的体系结构、照明要求的各种场所。无论照明和室内装饰照明还是道路照明和户外庭院建筑的光照明,所有的都展示了照明技术的发展和建筑照明的好处与便利。
电气工程专业英语翻译
实用资料：电气工程专业课(电力类)翻译参考 专业外语：Professional English 电路（上） electrical circuit (I) 电路（下） electrical circuit (II) 金工实习 machinery practice 电机（上） electrical machinery (I) 电工实验与测试 electrical experiment & test 电子综合实践 integrated electronic practice 信号与系统 signal & system 电子技术基础（模拟） fundamentals of electronic (analog) 电磁场electromagnetic field 电子技术实验 electronic experiment(I) 电子辅助设计EDA Electronic Design Automatic(I) 发电厂动力工程基础 Heat power engineering in generating plant 企业管理 enterprise management 电气主系统electrical system principle 电力系统稳态/暂态分析 Steady-State/ Transient-State Analysis of Power System 电力系统继电保护 Power System Relaying Protection 电力系统潮流计算机分析：Computer Analysis of Power Flow 数字电子技术 Digital Electrical Technique 微机原理 microcomputer principle 电子技术基础（数字） fundamentals of electronic (digital) 自动控制 automatic control theory 电力系统分析 electric power system analysis 电子技术基础实验electronic experiment(II) 电气主系统课程设计 electrical system principle-course design 电子辅助设计EDA Electronic Design Automatic(II) 通信与计算机网络 communication & computer networks 电力系统继电保护 electric power system relaying 电力系统继电保护 Power System Protective Relaying 电力系统远动技术electric power system remote protocol 生产实习productive practice Technology 继电保护课程设计 electric power system relaying-course design 电力电子技术 power electronics 电力电子技术基础：Fundamentals of Electronics Power Technology 电力电子课程设计 Power electronics course design 电力系统自动控制 electric power system control & automation 高电压技术 High voltage engineering Technology 变电站自动化 substation automation 电力经济 electric power system economics 电能质量控制 electric power quality control 配电网自动化 distribution system automation 电力系统新技术 new techniques on electric power system
多专业标识中英文翻译
标识类中英文翻译对照表
1 当心触电 Danger！High Voltage 2 当心碰撞 Beware of Collisions 3 当心台阶 Mind the Step/Watch Your Step 4 小心玻璃 Caution! Glass 5 小心滑倒/小心地滑 Caution! Slippery/Caution! Wet Floor 6 小心碰头 Mind Your Head/Watch Your Head 7 注意安全 CAUTION!/Caution! 8 注意防火 Fire Hazard Area 9 非公莫入 Staff Only 10 禁止鸣笛 No Horn 11 勿扔垃圾/请勿乱扔废弃物 No Littering 12 禁止停车 No Parking 13 禁止停留 No Stopping 14 禁止吸烟 No Smoking 15 拉 PULL/Pull 16 推 PUSH/Push 17 入口 ENTRANCE/Entrance 18 出口/安全出口/安全通道 EXIT/Exit 19 紧急出口 Emergency Exit 20 紧急救护电话（120） First Aid Call 120 21 紧急疏散地 Evacuation Site 22 请勿跨越 No Crossing 23 请勿拍照 No Photography 24 请勿摄影 No Filming / No Video 25 请勿使用闪光灯 No Flash Photography 26 火警电话119 Fire Call 119/Fire Alarm 119 27 投诉电话 Complaints Hotline 28 危难时请速报110 Emergency Call 110 29 危险，请勿靠近 Danger! Keep Away 30 请绕行 Detour 31 请勿打电话 No Phone Calls 32 请勿带宠物入内 No Pets Allowed 33 请勿抚摸/请勿触摸 Don't Touch 34 请勿践踏草坪 Please Keep Off the Grass 34 请勿坐卧停留 No Loitering 35 请爱护公共财产 Please Protect Public Property 36 请爱护公共设施 Please Protect Public Facilities 37 请节约用水 Please Save Water /Don't Waste Water 38 请您保管好自己的物品 Take Care of Your Belongings 39 请按顺序排队 Please Line Up 40 安全疏散指示图/紧急疏散指示图 Evacuation Chart 41 保持安静/请勿大声喧哗 Quiet Please 42 残疾人专用 Disabled Only 43 留言栏 Complaints & Suggestions 44 伸手出水 Automatic Tap 45 随手关门 Keep Door Closed/Please close the door behind you. 46 禁止入内/严禁入内 No Entry/No Admittance 47 闲人免进/请勿入内 Staff Only /No Admittance 48 谢绝参观/游客止步 No Admittance 49 正在维修 Repairs in Progress 50 有电危险 Danger! Electric Shock Risk
电气专业术语中英文对照
一．电气名词 Electric items 二．线路（母线、回路）Lines (Bus , circuits) 三．设备 Equipments 四．保护、继电器 Protection , relays 五．电气仪表 Electric instruments 六．防雷 Lightning protection 七．接地 Grounding , earthing 八．室、所 Room , Substation 九．电修车间设备 Equipments of electric repair 十．材料 Material 十一．图名 Drawings , diagrams 十二．表头 Tables 十三．标准图词汇 Terms from standard DWG 一．电气名词 Electric items 交（直）流 Alternating (direct) current 短路电流 Short-circuit current 起始次暂态短路电流 Initial subtransient short-circuit current 冲击电流 Impulse current 稳态短路电流 Steady state short-circuit current 临界电流 Critical current 切断电流 Rupturing current 熔断电流 Blow-out current 故障电流 Fault current 计算电流 Calculating current 极限有限电流 Limit effective current 过电流 Over current 逆电流 Inverse current 整定电流 Setting current 额定电流 Rated current 电流密度 Current density 短路电流最大有效值 Maximum effective value of short-circuit current 高压 High-voltage , High-tension 低压 Low-voltage , Low-tension 计算电压 Calculating voltage 激磁电压 Exciting voltage 冲击电压 Impulse voltage 临界电压 Critical voltage 残留电压 Residual voltage 击穿电压 Puncture voltage 脉动电压 Pulsating voltage 供电电压 Supply voltage 电力电压 Power voltage
大学各个专业名称的英文翻译
中文学科、专业名称英文学科、专业名称哲学Philosophy 哲学Philosophy 马克思主义哲学Philosophy of Marxism xx 哲学Chinese Philosophy xx 哲学Foreign Philosophies 逻辑学Logic 伦理学Ethics 美学Aesthetics 宗教学Science of Religion 科学技术哲学Philosophy of Science and Technology 经济学Economics 理论经济学Theoretical Economics 政治经济学Political Economy 经济思想史History of Economic Thought 经济史History of Economic
西方经济学Western Economics 世界经济World Economics 人口、资源与环境经济学Population, Resources and Environmental Economics 应用经济学Applied Economics 国民经济学National Economics 区域经济学Regional Economics 财政学(含税收学) Public Finance (including Taxation) 金融学(含保险学) Finance (including Insurance) 产业经济学Industrial Economics 国际贸易学International Trade 劳动经济学Labor Economics 统计学Statistics 数量经济学Quantitative Economics 中文学科、专业名称英文学科、专业名称 国防经济学National Defense Economics
电气自动化专业毕业论文英文翻译
电厂蒸汽动力的基础和使用 1.1 为何需要了解蒸汽 对于目前为止最大的发电工业部门来说, 蒸汽动力是最为基础性的。 若没有蒸汽动力, 社会的样子将会变得和现在大为不同。我们将不得已的去依靠水力发电厂、风车、电池、太阳能蓄电池和燃料电池,这些方法只能为我们平日用电提供很小的一部分。 蒸汽是很重要的,产生和使用蒸汽的安全与效率取决于怎样控制和应用仪表,在术语中通常被简写成C&I(控制和仪表 。此书旨在在发电厂的工程规程和电子学、仪器仪表以 及控制工程之间架设一座桥梁。 作为开篇,我将在本章大体描述由水到蒸汽的形态变化,然后将叙述蒸汽产生和使用的基本原则的概述。这看似简单的课题实际上却极为复杂。这里, 我们有必要做一个概述:这本书不是内容详尽的论文,有的时候甚至会掩盖一些细节, 而这些细节将会使热力学家 和燃烧物理学家都为之一震。但我们应该了解,这本书的目的是为了使控制仪表工程师充 分理解这一课题,从而可以安全的处理实用控制系统设计、运作、维护等方面的问题。1.2沸腾:水到蒸汽的状态变化 当水被加热时,其温度变化能通过某种途径被察觉(例如用温度计 。通过这种方式 得到的热量因为在某时水开始沸腾时其效果可被察觉,因而被称为感热。 然而,我们还需要更深的了解。“沸腾”究竟是什么含义?在深入了解之前,我们必须考虑到物质的三种状态:固态,液态,气态。 (当气体中的原子被电离时所产生的等离子气体经常被认为是物质的第四种状态, 但在实际应用中, 只需考虑以上三种状态固态,
物质由分子通过分子间的吸引力紧紧地靠在一起。当物质吸收热量,分子的能量升级并且 使得分子之间的间隙增大。当越来越多的能量被吸收,这种效果就会加剧,粒子之间相互脱离。这种由固态到液态的状态变化通常被称之为熔化。 当液体吸收了更多的热量时,一些分子获得了足够多的能量而从表面脱离,这个过程 被称为蒸发(凭此洒在地面的水会逐渐的消失在蒸发的过程中,一些分子是在相当低的 温度下脱离的,然而随着温度的上升,分子更加迅速的脱离,并且在某一温度上液体内部 变得非常剧烈,大量的气泡向液体表面升起。在这时我们称液体开始沸腾。这个过程是变为蒸汽的过程,也就是液体处于汽化状态。 让我们试想大量的水装在一个敞开的容器内。液体表面的空气对液体施加了一定的压 力,随着液体温度的上升,便会有足够的能量使得表面的分子挣脱出去,水这时开始改变 自身的状态,变成蒸汽。在此条件下获得更多的热量将不会引起温度上的明显变化。所增 加的能量只是被用来改变液体的状态。它的效用不能用温度计测量出来,但是它仍然发生 着。正因为如此,它被称为是潜在的,而不是可认知的热量。使这一现象发生的温度被称为是沸点。在常温常压下,水的沸点为100摄氏度。 如果液体表面的压力上升, 需要更多的能量才可以使得水变为蒸汽的状态。 换句话说, 必须使得温度更高才可以使它沸腾。总而言之,如果大气压力比正常值升高百分之十,水必须被加热到一百零二度才可以使之沸腾。