[单选题]某构件采用机械张拉后张法施工,孔道长度为29.8m,预应力筋为单根粗钢筋,每根长88米,两端均用螺丝端杆锚具,则对焊接头数量为( )个.A.3B.4C.5D.6
[单选题]交易成本论认为,交易资产的价值取决于( )A.产品的数量和质量B.交易双方的意愿C.买卖关系的连续性D.交易风险的消除
[阅读理解]Sound sleep occurs when one.s internal clock is regulated.Circadian rhythms(生理节奏)canbecome compromised quite easily.Many people with sleep troubles tend to vary bedtimes.To avoid thiscommon problem,sleep sufferers should go to bed and wake up at the same time every day.To helpimprove circadian rhythms,sufferers should enjoy 15 minutes of sun exposure the first thing in themorning.A bedtime routine can help prevent insomnia(失眠).One hour before bedtime,one should lowerthe lights and relax.Reading a book or listening to calm music can help prepare the body for a goodnight.s sleep.Taking a warm,candlelit bath or drinking a cup of warm milk can also help you preparefor deep sleep at night.Stress can have a bad effect on the body and the ability to sleep.A daily exercise routine can helplower the body.s stress naturally.One can also manage stress by writing diaries.Writing diaries canhelp people express their anxieties,plan for the future and improve sleep.Other ways to lower stressinclude deep breathing exercises and progressive muscle relaxation.The light sending out from computers,cellphones,tablets and televisions can cause sleepproblems.Therefore,these items should be turned off at least an hour before bedtime.Additionally,lowering the backlight on these electronic devices earlier in the evening can help you fall asleep fasterand stay asleep longer once bedtime arrives.A perfect bedroom invites sweet sleep.Most people sleep better in a cool,dark,and quiet room.Lower the temperature in the room to 16~20 degrees for a peaceful night.s sleep. A dark room can beaccomplished by installing light blocking curtains or wearing a sleep mask.Noise can be reduced witheither earplugs or a white noise machine.Finally,a comfortable mattress(床垫)and pillows areessential to a good night.s sleep.36.What is the passage mainly about A.How to get a sound sleep.B.How to lower body stress.C.How to regulate internal clocks.D.How to manage anxieties.37.According to Paragraph 2,which of the following may lead to insomnia A.Reading a book for relaxation before bedtime.B.Lowering lights one hour before bedtime.C.Drinking some warm milk before bedtime.D.Listening to rock music before bedtime.38.What can be done to reduce stress A.Doing exercise every day.B. Making plans for the future.C.Writing about your sleep patterns.D. Learning to hold your breath.39.What is the perfect condition for sleep A.A quiet room with flashing lights.B.A brightroom with white curtains.C.A cool room with comfortable pillows.D.A darkroom with electronic devices.
[填空题]二一十进制数转换的连减法适用于 .
[阅读理解]二、阅读下面文字,完成1~4题.电磁波已成为一种新的污染源.它看不见,摸不着,穿透力强,充斥着整个空间,令人防不胜防.电磁污染源主要包括两大类,即自然型电磁污染源与人工型电磁污染源.前者来源于某些自然现象,以雷电所产生的电磁污染最为突出.后者产生于人工制造的若干系统(如高压系统)、电子设备与电气装置.人体处在一定强度的电磁场下,会吸收辐射能量,发生生物学作用,包括热作用和非热作用.所谓热作用,就是高频电磁波对生物机体细胞的“加热”作用.人体接受电磁辐射后,体内的分子会受到磁场的影响而重新排列,在重排过程中,分子间相互碰撞、摩擦而产生热能,引起热作用.人体内电解质溶液的离子因受到电场的作用而发生移动(传导电流),也能使电解质变热.另外,由于人体内某些成分(如体液等)为导体,还可产生局部性感应涡流,也会产生热.如果人体吸收的辐射能太多,靠体温的调节无法把热量散发出去,就会引起体温升高,进而引发各种病症.由于电磁波是穿透生物表层直接对内部组织“加热”,往往机体表面看不出什么,而内部组织却已严重“烧伤”.至于电磁波的非热作用问题,正在进一步研究之中,一般认为是低频波产生的影响.人体被电磁波辐射后,体温并未明显升高,但已经干扰了人体的固有微弱电磁场,造成细胞内遗传基因发生畸形突变,进而诱发白血病和肿瘤,还会引发胚胎染色体改变,导致婴儿的畸形或孕妇的自然流产.鉴于电磁辐射对人体的危害,联合国人类环境会议已将防治电磁辐射污染列为环境保护项目.1.属于自然型电磁污染源的一项是( ).A.家用电器B.高压、超高压系统C.雷雨天气D.无线电广播通信设备2.下列说法,不能解释高频电磁波在人体内引起热作用的一项是( ).A.磁场使人体内的分子重新排列B.体温调节无法把热量散发出去C.电场使人体内电解质离子发生移动D.电经质所3.下列说法组成四个选项,全都符合文意的一项是( ).①热作用是人体在电磁场下体温升高的一种物理反应.②引发热作用和非热作用的电磁波的频率是不同的.③研究证明,白血病和肿瘤是由于低频电磁波干扰人体微弱电磁场而造成的.④人处在一定强度的电磁场中,就会发生热作用或非热作用.⑤电磁波对机体表层不会造成明显损伤.A.②④⑤B.①③④c.②③⑤D.①②③4.如果给这篇短文拟一个标题,最恰当的一项是( ).A.危害人体的电磁辐射B.电磁辐射与环保C.电磁辐射的热作用和非热作用D.无处不在的电磁辐射
[填空题]磁路基尔霍夫定律的含义是什么
[填空题]设有三相负载Z=|Z|∠QZb=|Zb|..若|Z0|=|Zb|=|Z|ψa=ψb=ψc,则称此三相负载为______.
[单选题]以下不属于E.S功能内容的是( )A.自动发电控制B.经济调度C.静态安全分析D.负荷管理
[问答题]输入100名学生的出生月份,统计并输出每个月份过生日的学生人数.#include #define N 100void main ( ){int i, month;int birth[13]={0};/*birth[1]~birth[12]分别保存1~12月过生日的学生数*/for (i=1;i=1 && month<=12) birth[month]++;}for (i=1;___;i++) /*第二空*/printf(%d month___\n,i, birth[i]); /*第三空*/}
[单选题]以下不属于E.S功能内容的是( )A.自动发电控制B.经济调度C.静态安全分析D.负荷管理
[问答题]输电线路电压降落,电压损耗的含义分别是什么
[单选题]Several novels by Mo Yaninto E.glish so far.B.were translatedA. had been translatedD.have been translatedC.are translated
[单选题]根据加里?德斯勒个人职业生涯发展的五阶段论,45岁到65岁阶段属于A.探索阶段B.下降阶段C.维持阶段D.确立阶段
[单选题]大型异步电动机不允许直接起动,其原因是( )A.机械强度不够B.电机温升过高C.起动过程太快D.对电网冲击太大
[名词解释]电汇
[单选题]以下提高导体载流量的方法哪一个是错误的_______.A.增加导体截面积B.提高长期发热最高允许温度C.采用电阻率小的材料D.采用电阻率大的材料
[单选题]截断误差是( )产生的误差.A.A. 只取有限位数B.模型准确值与用数值方法求得的准确值之差C.观察与测量D.数学模型准确值与实际值
[填空题]有三个电容器的电容量分别是C1、C2和C3,已知C1> C2> C3,将它们并联在适当的电源上,则它们所带电荷量的大小关系是( )
[填空题]两个以上触点串联形成的支路叫串联电路块指令的是 .
[多选题]兰州市的地域形态主要是受 ( )A.气候的影响B.河流的影响C.地形的影响D.政治因素的影响
[填空题]短路的形式有: 两相接地短路 三相短路,两相短路,单相短路.发生 单相短路 短路可能性最大. ( ) 短路的短路电流最大,因此造成 的危害最大.