【判断题】
>单相整流电路适用于小功率整流，三相整流电路更适用于大功率整流
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相关试题
【判断题】
>三相整流电路最基本的是三相半波整流电路，其他类型都是由三相半波整流电路以不同方式组合而成的
【判断题】
>单管功率放大器的静态工作点设置较高，是造成电路效率低的主要原因
【判断题】
>当电容器极板面积、极板内表面距离及中间介质一定时，极板上所带电荷量越多，两极板间电压越大
【判断题】
>电机的轴承，其润滑脂应填满整个轴承空间
【判断题】
>起重机起吊时，在起重臂下行走，必须戴好安全帽
【判断题】
>起吊设备时，只允许一人指挥，同时指挥信号必须明确
【判断题】
>桥式起重机设立零位保护的目的是防止当控制器的控制手柄不在零位时，电源断电后又重新送电时，电动机自行启动而发生事故
【判断题】
>X62W型铣床工作台上、下、前、后、左、右6个方向的进给运动是靠操纵手柄来实现的，各方向的进给不能同时接通
【判断题】
>X62W型铣床当主轴电机转速低于110r/min左右时，速度继电器的常开触头应处于闭合状态，直到制动结束
【判断题】
>T610型卧式镗床主轴和平旋盘无级变速电路是利用测速发电机电压与参考电压的差值来控制晶体管开关电路，再由开关电路控制继电器来对主轴电机进行无级调速
【判断题】
>移动式电动工具、手持式电动工具应加装高灵敏动作的漏电保护器
【判断题】
>变压器室、配电室、电容器室的门应向外开启，相邻配电室之间有门时，此门应能双向开启
【判断题】
>帮助触电者脱离电源时，不可直接用人的肢体或其他金属及潮湿的物体作为救护工具
【判断题】
>低压设备或做耐压实验的四周围栏上可以不用悬挂标示牌
【判断题】
>机床电气设备维护保养时，设备中的时间继电器应进行调整
【判断题】
>中、小功率的电动机短路保护时，应使用熔断器或热继电器
【判断题】
>直流单臂电桥测电阻时，应选用短粗的连接导线并拧紧
【判断题】
>双速电动机的定子绕组在低速时是三角形联接，高速时是双星形联接
【判断题】
>“五同时”是指企业生产(经营)的领导者和组织者，必须明确安全与生产是一个有机的整体，要将安全与生产的产量(进度)一起抓，在生产工作的时候，同时计划、布置、安排、检查、总结、评比安全工作
【判断题】
>当电路中的参考点改变时，某两点间的电压也将随之改变
【判断题】
>电气原理图设计中，应尽量减少通电电器的数量
【判断题】
>从各相首端引出的导线叫相线，俗称火线
【判断题】
>电气接线图中，同一电器元件的各部分不必画在一起
【判断题】
>变压器油的作用是加强变压器内部的绝缘和散热
【判断题】
>电气原理图中，位置开关应按挡块碰撞前的状态绘制
【判断题】
>在装配图中，键是实现轴上零件周向定位的零件，为保证其装卸，键的各表面与其他零件的表面应有适当的间隙
【判断题】
>钻小孔时应选择较大的进给量和较低的转速
【判断题】
>静电最主要的危害就是可能引起火灾和爆炸事故
【判断题】
>在带有电容器的供电线路停电作业时，只要断开电源后即可进行检修工作
【判断题】
>三相三线有功电能表能够准确计量三相四线制电路的有功电量
【判断题】
>单相变压器一、二次绕组的同名端同时取为首端(或末端)时，一、二次绕组的相电压U1和U2应为同相位
【判断题】
>自耦变压器降压启动结束后，自耦变压器的高压绕组仍与电源连接，不必切除，只把其低压绕组与电机定子切除即可
【判断题】
>电机电刷磨损后，应按电机制造厂规定的同一型号进行更换
【判断题】
>如果电机的轴承没有洗净或润滑脂内有杂质、水分，轴承极易损坏
【判断题】
>起重设备和吊装工具规格应比起吊设备或工件的重量小
推荐试题
【单选题】
你的项目正处于制订人力资源计划过程中。 为了获得资源， 你曾几次拜访工程设计部门的职能经理。 但是， 他总是以 “ 腾不出人手” 为由， 谢绝给你提供人员。如果缺少工程设计部门的员工， 项目将遇到很大的困难甚至完全无法开展。 为了取得他的支持， 你应该借助 （ ）。
A. 项目管理计划
B. 项目章程
C. 工作分解结构
D. 责任分配矩阵
【单选题】
你的某些团队成员之间的沟通经常出现问题， 导致合作欠佳。 你计划抽一个周末， 把整个团队带到一个度假村参加一系列拓展训练， 并组织篮球、 排球和足球比赛。 这些活动最有利于改善 （ ）。
A. 团队绩效
B. 项目质量
C. 团队士气
D. 个人绩效
【单选题】
项目正处于收尾阶段， 很快就可以做完财务收尾、 法律收尾和行政收尾。 在收尾阶段的最后， 项目经理必须把项目正式关门， 并且 （ ）
A. 把对项目成果的照管责任转移给指定的相关方
B. 解决与采购合同有关的一切未决问题
C. 完成对项目成果的正式验收
D. 更新项目管理计划
【单选题】
项目上出现了一个异常问题， 项目经理希望重要相关方尽快关注这个问题， 并采取相应行动来支持项目经理对问题的处理。 项目经理应该给他们发送 （ ）。
A. 工作绩效数据
B. 工作绩效信息
C. 质量控制测量结果
D. 工作绩效报告
【单选题】
在项目进展过程中，团队成员经常变化。那些已经完成相关工作的成员， 应该及时从项目中遣散，以便节约项目成本，并使他们能顺利过渡到下一个项目或回到职能部门。 在某个成员因完成工作而离开时，项目经理应该 （ ）。
A. 给他复制一份项目资料留作纪念
B. 更新成员的档案， 记录他在本项目上的表现
C. 邀请成员参加完工聚会
D. 确保他的离开不会影响项目工作
【单选题】
项目进入收尾阶段， 项目经理和项目管理团队需要履行对组织过程资产更新的责任。 以下哪项是他们应该做的事情？ （ ）
A. 更新组织中的项目管理政策
B. 更新组织中的项目管理程序
C. 更新组织中的共享项目知识库
D. 更新组织中的项目管理工作指南
【单选题】
你所管理的项目将需要在多个物理地点展开， 涉及的风险比较多。 你从公司的组织过程资产中了解到， 过去类似项目的风险管理工作比较混乱。 你想要在本项目上改变这种局面。 为了有效地管理本项目的风险， 你首先应该 （ ）。
A. 识别潜在的风险及影响
B. 指定专门人员负责风险管理
C. 编制风险管理计划
D. 编制风险登记册
【单选题】
项目提前终止， 发起人要求提交收尾文件， 以便了解项目的最终情况。 在此份文件中， 项目经理应该注意包括以下信息， 除了 （ ）。
A. 项目终止的原因
B. 项目偏差情况
C. 移交阶段可交付成果的正式程序
D. 项目成员遣散计划
【单选题】
ABB 公司与某水电站业主签订了电站开关站和高压输电线路的设备供货和安装合同。在安装施工过程中， 卖方抱怨买方没有及时为 ABB 公司清理安装现场， 这可能影响工期。 合同规定场地清理是买方的职责之.。 作为买方的项目经理，你将 （ ）。
A. 告诉卖方自己清理安装现场
B. 签发合同变更令， 更改合同
C. 从项目中取消安装现场清理这一工作
D. 预期将收到卖方的合同索赔
【单选题】
需要聘请一位咨询专家为本项目提供技术咨询服务。 现在， 只知道这类咨询服务工作的性质， 还不知道究竟需要多少时日的咨询服务。 为了尽快签订咨询服务合同， 最好采用哪种合同类型？ （ ）
A. 总价合同
B. 成本补偿合同
C. 总价加经济价格调整合同
D. 时间和手段合同
【单选题】
在项目的执行阶段，一个新成员加入了项目团队。项目经理要求他先跟着一个经验丰富的老成员实习一个月。 这种工作跟随方式最有利于 （ ）。
A. 新成员与老成员发展个人友谊
B. 新成员迅速有效地融人团队
C. 新成员学习老成员的显性知识
D. 新成员学习老成员的隐性知识
【简答题】
攻势已经持续了三天，但是我们并没有取得多少进展。师长命令我们营夜晚绕到敌人后方发起突然袭击。然而，要绕到敌人后方，我们必须越过一片沼泽地。我们很多人担心会陷入泥潭之中。我们营长决定冒下险。所幸由于寒冷天气沼泽地都结上了冰，我们于天亮前到达目的地并从敌人后方发起进攻。这一下扭转了战局。敌人没有戒备，不久便投降了。
【简答题】
汽年自从发明以来使交通运输发生了草命性的变化，永远地改变了人们的生活、旅行和办事的方式。但另ー方面，也带来了危害，尤其是公路死亡事故。然而，现今由于计算机技术和电子传感器的使用，有可能消除发生的大多数交通事故。例如，装在你汽车上的电子传感器能检测到空气中的酒精雾汽并拒绝启动引擎。同样，传感器还能通过接受在轨道上运行的卫星发出的信号监测路况并大大减少你陷入交通拥堵的可能性。
【简答题】
常言道，好的开端是成功的一半。在求职时，求职者事先做好充分的准备是非常重要的。我认为，事先做不做准备显然会影响求职者的成功机会。
我的一位朋友在一家大型计算机软件公司供职，年薪十万美元左右。他根据自己的经历告诉我说，那些面试未来雇员的具有录用决定权的人喜欢有充分准备的人。那些没有在了解未来雇主方面尽全力的人很难有成功的希望。
【简答题】
全球化对中国年轻人具有重大影响。例如，年轻的农民正在大规模流向城市寻找工作。而对那些想出国深造或进外企工作的年轻人来说，英语变得越来越重要。另一方面，许多海外学子近年来回归祖国，因为他们看好中国经济的长期增长前景。因特网加强了中国年轻人和其他地方年轻人的联系。他们跟踪最新的潮流，模仿外国的时尚。他们中一些人似乎不在乎中国的传统美德，更不要说发扬光大，这使得有人忧虑中国传统文化会不会有一天终将消失。
【简答题】
就我来说，我发现外表往往是靠不住的。譬如，要是你仅凭外表去判断诸如爱德华・海德・伯顿这样的人，你就错了。外表上，伯顿像是个表里一致的人。他个子很小，满头白发，有着一双温和、蔚蓝的眼睛，文雅且坦率。然而，他原来却是十分的残忍。他侮辱和愚弄穷困潦倒的伦尼，让他去做那样的蠢事。更让人吃惊的是，他对伦尼的死全然冷漠无情。毫无疑问，他是个铁石心肠的家伙。
【简答题】
They say that pride comes before a fall. In the case of both Napoleon and Hitler, the many victories they enjoyed led them to believe that anything was possible, that nothing could stand in their way. Russia's icy defender was to prove them wrong.
【简答题】
In 1812, Napoleon Bonaparte, Emperor of the French, led his Grand Army into Russia. He was prepared for the fierce resistance of the Russian people defending their homeland. He was prepared for the long march across Russian soil to Moscow, the capital city. But he was not prepared for the devastating enemy that met him in Moscow -- the raw, bitter, bleak Russian winter.
【简答题】
In 1941, Adolf Hitler, leader of Nazi Germany, launched an attack against the Soviet Union, as Russia then was called. Hitler's military might was unequaled. His war machine had mowed down resistance in most of Europe. Hitler expected a short campaign but, like Napoleon before him, was taught a painful lesson. The Russian winter again came to the aid of the Soviet soldiers.
【简答题】
In the spring of 1812, Napoleon assembled an army of six hundred thousand men on the borders of Russia. The soldiers were well trained, efficient, and well equipped. This military force was called the Grand Army. Napoleon, confident of a quick victory, predicted the conquest of Russia in five weeks.
【简答题】
Shortly afterwards, Napoleon's army crossed the Neman River into Russia. The quick, decisive victory that Napoleon expected never happened. To his surprise, the Russians refused to stand and fight. Instead, they retreated eastward, burning their crops and homes as they went. The Grand Army followed, but its advance march soon became bogged down by slow-moving supply lines.
【简答题】
In August, the French and Russian armies engaged at Smolensk, in a battle that left over ten thousand dead on each side. Yet, the Russians were again able to retreat farther into Russian territory. Napoleon had won no decisive victory. He was now faced with a crucial decision. Should he continue to pursue the Russian army? Or should he keep his army in Smolensk for the approaching winter?
【简答题】
Napoleon took the gamble of pressing on to Moscow, 448 kilometers away. On September 7, 1812, the French and Russian armies met in fierce battle at Borodino, 112 kilometers west of Moscow. By nightfall, thirty thousand French and forty-four thousand Russians lay dead or wounded on the battlefield.
【简答题】
Again, the Russian army retreated to safety. Napoleon had a clear path to Moscow, but the occupation of the city became an empty victory. The Russians fled their capital. Soon after the French arrived, a raging fire destroyed two-thirds of the city. Napoleon offered a truce to Alexander I, but the Russian czar knew he could bide his time: "We shall let the Russian winter fight the war for us."
【简答题】
Napoleon soon realized he could not feed, clothe, and quarter his army in Moscow during the winter. In October 1812, he ordered his Grand Army to retreat from Moscow.
【简答题】
The French retreat turned into a nightmare. From fields and forests, the Russians launched hit-and-run attacks on the French. A short distance from Moscow, the temperature had already dropped to minus 4 degrees Celsius. On November 3, the winter's first snow came. Exhausted horses fell dead in their tracks. Cannon became stuck in the snow. Equipment had to be burned for fuel. Soldiers took ill and froze to death. The French soldiers dragged on, leaving the dead along every mile.
【简答题】
As the Russian army was gathering its strength, the French had to flee Russia to avoid certain defeat. At the Berezina River, the Russians nearly trapped the retreating French by burning the bridges over the swollen river. But Napoleon, by a stroke of luck, was able to build two new bridges. Thousands of French soldiers escaped, but at the cost of fifty thousand dead. Once across the Berezina, the tattered survivors limped toward Vilna.
【简答题】
Of the six hundred thousand soldiers Napoleon had led into Russia, less than one hundred thousand came back. The weakened French army continued its retreat westward across Europe. Soon, Britain, Austria, Russia, and Prussia formed a powerful alliance and attacked these stragglers. In March 1814, Paris was captured. Napoleon abdicated and went into exile, his empire at an end.
【简答题】
By early 1941, Adolf Hitler, leader of Nazi Germany, had seized control of most of Europe. To the east of Hitler's German empire was the Soviet Union. On June 22, 1941, without a declaration of war, Hitler began an invasion of the Soviet Union that was the largest military land campaign in history. Confident of a quick victory, Hitler expected the campaign to last no longer than three months. He planned to use the blitzkrieg, or "lightning war," tactics that had defeated the rest of Europe. The invasion had three broad thrusts: against Leningrad and Moscow and through the Ukraine.
【简答题】
Caught off guard by the invasion, Soviet leader Joseph Stalin instructed the Russian people to "scorch the earth" in front of the German invaders. Farms and factories were burned, destroyed, or rendered useless. During the first ten weeks of the invasion, the Germans pushed the front eastward, and the Russians suffered more than a million casualties.
【简答题】
In the north, the Germans closed in on Leningrad. Despite great suffering, however, the people of Leningrad refused to surrender. As the battle of Leningrad dragged on into winter, the city's situation became desperate. As food ran out, people died from hunger and disease. By the middle of the winter of 1941-1942, nearly four thousand people starved to death every day. Close to one million people died as a result of the siege.
【简答题】
In the center of Russia, Hitler's goal was the capture of Moscow. Because the Germans had anticipated a quick victory, they had made no plans for winter supplies. October arrived with heavy rains. "General Mud" slowed down the movement of the Germans' lightning attack.
【简答题】
As Hitler's armies drew closer and closer to Moscow, an early, severe winter settled over the Soviet Union, the harshest in years. Temperatures dropped to minus 48 degrees Celsius. Heavy snows fell. The German soldiers, completely unprepared for the Russian winter, froze in their light summer uniforms. The German tanks lay buried in the heavy snowbanks. The Russian winter brought the German offensive to a halt.
【简答题】
By the summer of 1942, Hitler had launched two new offensives. In the south, the Germans captured Sevastopol. Hitler then pushed east to Stalingrad, a great industrial city that stretched for 48 kilometers along the Volga River. Despite great suffering, Soviet defenders refused to give up Stalingrad.
【简答题】
In November 1942, the Russians launched a counterattack. With little or no shelter from the winter cold in and around Stalingrad, German troops were further weakened by a lack of food and supplies. Not until January 1943 did the Germans give up their siege. Of the three hundred thousand Germans attacking Stalingrad, only ninety thousand starving soldiers were left. The loss of the battle for Stalingrad finally turned the tide against Hitler. The German victories were over, thanks in part to the Russian winter.
【简答题】
During 1943 and 1944, the Soviet armies pushed the German front back toward the west. In the north, the Red Army broke the three-year siege of Leningrad with a surprise attack on January 15, 1944. Within two weeks, the heroic survivors of Leningrad saw their invaders depart. By March 1944, the Ukraine farming region was again in Soviet hands. On May 9, 1944, Sevastopol was liberated from the Germans. The Russians were now heading for Berlin.
【简答题】
For Hitler, the invasion of the Soviet Union had turned into a military disaster. For the Russian people, it brought unspeakable suffering. The total Soviet dead in World War II reached almost 23 million.
【简答题】
The elements of nature must be reckoned with in any military campaign. Napoleon and Hitler both underestimated the severity of the Russian winter. Snow, ice, and freezing temperatures took their toll on both invading armies. For the Russian people, the winter was an icy defender.
【单选题】
________不属于鼠类及体表寄生虫携带的病原体。___
A. 鼠疫耶尔森菌
B. 汉坦病毒
C. 黄病毒属病毒
D. 致病性钩端螺旋体
【单选题】
病媒生物死体样本运送，如果在24h内不能到达实验室的，运送过程中箱内温度应保持在_____。___
A. 4℃以下
B. 0℃以下
C. -20℃以下
D. 4℃以上
