【判断题】
埋弧焊在中、厚板对接、角接接头有广泛应用，14 mm以下板材对接可以不开坡口。埋弧焊也可用于合金材料的堆焊上
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相关试题
【判断题】
等离子弧按电源供电方式不同，分为两种形式
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非转移型等离子弧：电极接电源正极，喷嘴接负极，而零件不参与导电。电弧是在电极和喷嘴之间产生
【判断题】
转移型等离子弧： 钨极接电源负极，零件接正极，等离子弧在钨极与零件之间产生
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气焊是利用气体火焰加热并熔化母体材料和焊丝的焊接方法
【判断题】
气焊常用于薄板的低碳钢、低合金钢、不锈钢的对接、端接，在熔点较低的铜、铝及其合金的焊接中仍有应用
【判断题】
中性焰是当氧气与乙炔的混合比为 1～1.2 时，燃烧充分，燃烧过后无剩余氧或乙炔，热量集中，温度可达 2050℃～2150℃
【判断题】
中性焰焰心是呈亮白色的圆锥体，温度较低；内焰呈暗紫色，温度最高，适用于焊接；外焰颜色从淡紫色逐渐向橙黄色变化，温度下降，热量分散
【判断题】
碳化焰是指当氧气与乙炔的混合比小于 1 时，部分乙炔未曾燃烧，焰心较长，呈蓝白色，温度最高达 2700℃～3000℃
【判断题】
氧化焰是指当氧气与乙炔的混合比大于 1.2时，燃烧过后的气体仍有过剩的氧气，焰心短而尖，内焰区氧化反应剧烈，火焰挺直发出“嘶嘶”声，温度可达 2100℃～2300℃
【判断题】
氧化焰由于火焰具有氧化性，焊接碳钢易产生气体，并出现熔池沸腾现象，很少用于焊接
【判断题】
电阻焊是将零件组合后通过电极施加压力，利用电流通过零件的接触面及临近区域产生的电阻热将其加热到熔化或塑性状态，使之形成金属结合的方法
【判断题】
点焊方法：将零件装配成搭接形式，用电极将零件夹紧并通以电流，在电流热作用下，电极之间零件接触处被加热熔化形成焊点
【判断题】
凸焊 是电加热后突起点被压塌，形成焊接点的电阻焊方法
【判断题】
对焊工作原理：将两零件端部相对放置，加压使其端面紧密接触，通电后利用电阻热加热零件接触面至塑性状态，然后迅速施加大的顶锻力完成焊接
【判断题】
电渣焊是一种利用电流通过液体熔渣所产生的电阻热加热熔化填充金属和母材，以实现金属焊接的熔化焊接方法
【判断题】
电渣焊适用于厚板、大断面、曲面结构的焊接，如火力发电站数百吨的汽轮机转子、锅炉大厚壁高压汽包等
【判断题】
激光焊是利用大功率相干单色光子流聚集而成的激光束为热源进行焊接的方法
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焊接时，焊件仅在局部区域被加热到高温，离焊缝愈远，温度愈高，膨胀也愈大
【判断题】
焊接产生拉应力和压应力，当这些应力超过金属的强度极限时，将产生焊接变形；当超过金属的屈服极限时，则会出现裂缝
【判断题】
未焊透是指工件与焊缝金属或焊缝层间局部未熔合的一种缺陷
【判断题】
裂纹是最危险的一种缺陷，它除了减少承载截面之外，还会产生严重的应力集中，在使用中裂纹会逐渐扩大，最后可能导致构件的破坏
【判断题】
孔加工刀具都应同时完成两个运动。主运动，即沿着轴线方向对着零件的直线运动；进给运动，即刀具刀具绕轴线的旋转运动
【判断题】
CO2 气体保护焊设备可分为手动焊和自动焊两种类型
【判断题】
以惰性气体氩气作保护气的电弧焊方法有钨极氩弧焊和熔化极氩弧焊两种
【判断题】
由于被惰性气体隔离，焊接区的熔化金属不会受到空气的有害作用，所以钨极氩弧焊可用以焊接易氧化的有色金属如铝、镁及其合金
【判断题】
埋弧焊电弧产生于堆敷了一层的焊剂下的焊丝与零件之间，受到熔化的焊剂—熔渣以及金属蒸汽形成的气泡壁所包围
【判断题】
埋弧焊主要优点是焊接电流和电流密度大，生产效率高，是手弧焊生产率的 1～2 倍
【判断题】
气焊是利用气体火焰加热并熔化母体材料和焊条的焊接方法
【判断题】
锯条一般用工具钢或合金钢制成，并经淬火和高温回火处理
【判断题】
锯条规格用锯条两端安装孔之间距离表示，并按锯齿齿距分为粗齿、细齿二种
【判断题】
锯齿在制造时按一定的规律错开排列形成锯路
【判断题】
安装锯条时，锯齿方向必须朝前，锯条绷紧程度要适当
【单选题】
移动式供气源呼吸器可单人使用，也可___使用。
A. 多人同时
B. 两人同时
C. 3 人同时
D. 4人同时
【单选题】
移动式供气源4个气瓶允许每次更换___个空瓶而不中断供气。
【单选题】
移动式供气源配置4个6升/20兆帕气瓶时，1人使用可用___小时。
【单选题】
电绝缘手套最高测试电压为___伏。
A. 500
B. 5000
C. 10000
D. 20000
【单选题】
防高温手套的耐热温度为___℃。
A. 450
B. 900
C. 1200
D. 2000
【单选题】
防护器材按使用场合分为常规防护装备和___防护装备。
推荐试题
【单选题】
The introduction of Christianity to Britain added the first element of words to English.
A. A. Danish and Finnish
B. B. Dutch and German
C. C. French and Italian
D. D. Latin and Greek
【单选题】
The evolution of Middle English was reinforced by the influence.
A. A. Norman
B. B. Dutch
C. C. German
D. D. Danish
【单选题】
In Britain, the parliamentary general election is held every years.
A. A. three
B. B. four
C. C. five
D. D. six
【单选题】
has a distinct legal system based on Roman law.
A. A. Wales
B. B. England
C. C. Scotland
D. D. Northern Ireland
【单选题】
Generally speaking, the British Parliament operates on a system.
A. A. single-party
B. B. two-party
C. C. three-party
D. D. multi-party
【单选题】
The policies of the Conservative Party areThe policies of the Conservative Party are characterized by pragmatism and .
A. A. government intervention
B. B. nationalization of enterprises
C. C. social reform
D. D. a belief in individualism
【单选题】
The Labor Party affected the British society greatly in that it .
A. A. set up the National Health Service
B. B. improved public transportation
C. C. abolished the old tax system
D. D. enhanced the economic development
【单选题】
The British economy achieved global dominance by the .
A. A. 1860s
B. B. 1870s
C. C. 1880s
D. D.1890s
【单选题】
In , the British Parliament passed two important acts to establish a welfare state.
A. A. 1945
B. B. 1946
C. C. 1947
D. D. 1948
【单选题】
The in the early 1970s worsened an already stagnant economy in Britain.
A. A. oil crisis
B. B. high inflation rates
C. C. large imports
D. D. unemployment problem
【单选题】
Of the following practices, does not belong to Thatcher’s social welfare reform.
A. A. reducing child benefits
B. B. shortening the unemployment benefits period
C. C. reducing the unemployment
D. D. lowering old age pensions
【单选题】
The Blair government has been successful in all the following aspects except .
A. A. limiting government spending
B. B. keeping inflation under control
C. C. reducing unemployment
D. D. reducing inequality
【单选题】
Britain has devoted of its land area to agriculture.
A. A. 54%
B. B. 64%
C. C. 74%
D. D.84%
【单选题】
Britain’s important fishing areas include all the following except .
A. A. the North Sea
B. B. the English Channelnnel
C. C. The sea area around Ireland
D. D. The sea area between Britain and Ireland
【单选题】
Coal mining industry in Britain provides of the energy consumed in the country.
A. A. 1/3
B. B. 1/4
C. C. 1/5
D. D. 2/3
【单选题】
The car industry in Britain in mostly .
A. A. foreign-owned
B. B. state-owned
C. C. joint-venture
D. D. privately-owned
【单选题】
Of the following sectors in Britain, has experienced spectacular growth since the end of Word War II.
A. A. agriculture
B. B. energy industry
C. C. service industry
D. D. manufacturing industry
【单选题】
Samuel Johnson’s dictionary was influential in establishing a standard form of .
A. A. grammar
B. B. handwriting
C. C. spelling
D. D. pronunciation
【单选题】
At present, nearly of the world’s population communicate in English.
A. A. half
B. B. a quarter
C. C. one third
D. D. one fifth
【单选题】
The attack on Rome ended the Roman occupation in Britain in 410.
A. A. Norman
B. B. Danish
C. C. Celtic
D. D. Germanic
【单选题】
By the late 7th century, became the dominant religion in England.
A. A. Celtic Christianity
B. B. Anglo-Saxon Christianity
C. C. Germanic Christianity
D. D. Roman Christianity
【单选题】
Westminster Abbey was built at the time of .
A. A. St. Augustine
B. B. Edward the Confessor
C. C. William the Conqueror
D. D. Alfred the Great
【单选题】
The marked the establishment of feudalism in England.
A. A. Viking invasion
B. B. signing of the Magna Carta
C. C. Norman Conquest
D. D. Adoption of common law
【单选题】
The end of the Wars of the Roses led to the rule of .
A. A. the House of Valois
B. B. the House of York
C. C. the House of Tudor
D. D. the House of Lancaster
【单选题】
The direct cause for the Religious Reformation was King Henry VIII’s effort to .
A. A. divorce his wife
B. B. break with Rome
C. C. support the Protestants
D. D. declare his supreme power over the church
【单选题】
The English Civil War broke out in 1642 between .
A. A. Protestants and Puritans
B. B. Royalists and Parliamentarians
C. C. nobles and peasants
D. D. aristocrats and Christians
【单选题】
was passed after the Glorious Revolution.
A. A. Bill of Rights
B. B. Act of Supremacy
C. C. Provisions of Oxford
D. D. Magna Carta
【单选题】
The Industrial Revolution was aThe Industrial Revolution was accomplished in Britain by the middle of the century.
A. A. 17th
B. B. 18th
C. C. 19th
D. D. 20th
【单选题】
Britain faced strong challenges in its global imperial dominance by the beginning of the century.
A. A. 17th
B. B. 18th
C. C. 19th
D. D. 20th
【单选题】
As a revising chamber, the House of Lords is expected to the House of Commons.
A. A. rival
B. B. complement
C. C. criticize
D. D. inspect
【单选题】
The British government is characterized by a division of powers between three of the following branches with the exception of the .
A. A. judiciary
B. B. legislature
C. C. monarchy
D. D. executive
【单选题】
The importance of the British monarchy can be seen in its effect on .
A. A. passing the bills
B. B. advising the government
C. C. political parties
D. D. public attitude
【单选题】
British Cabinet works on the principle of .
A. A. collective responsibility
B. B. individual responsibility
C. C. defending the collectivism
D. D. defending the individuals
【单选题】
The main duty of the British Privy Council is to .
A. A. make decisions
B. B. give advice
C. C. pass bills
D. D. supervise the Cabinet
【单选题】
is the first African-American winner of the Nobel Prize for Literature.
A. A.Ralph Ellison
B. B. Tony Morrison
C. C. Richard Wright
D. D. James Baldwin
【单选题】
Of the following writers, is Not a Nobel Prize winner.
A. A. Alice Walker
B. B. Ernest Hemingway
C. C. William Faulkner
D. D. Eugene O’Neil
【单选题】
Of the following books, is NOT written by Ernest Hemingway.
A. A. The Sun Also Rises
B. B. The Sound and the Fury
C. C. A Farewell to Arms
D. D. For Whom the Bell Tolls
【单选题】
F. Scott Fitzgerald’s finest novel is , and its theme is about
A. A. The Great Gatsby, the American Dream
B. B. Tender is the Night, love
C. C. Tales of the Jazz Age, the loss of oneself
D. D. The Beautiful and the Damned, the evil of human nature
【单选题】
Of the following writers, is NOT included in the group of naturalists.
A. A. Stephen Crane
B. B. Frank Norris
C. C. Theodore Dreiser
D. D. Herman Melville
【单选题】
Of the following, is NOT characteristic of Mark Twain’s works.
A. A. colloquial speech
B. B. a sense of humor
C. C. a realistic view
D. D. an idealistic view
