热门试题:
[判断题]炼油厂装置区内的架空管道或装置起火,容易出现易燃可燃液体由上向下流淌的现象,形成立体火灾
A.正确
B.错误
[单项选择]急性药物过敏性间质性肾炎常见致病药物为()。
A. 青霉素类
B. 利尿药
C. 先锋霉素类
D. 磺胺类
E. 以上均是
[判断题]( )所谓触电是指电流流过人体对人体产生的生理和病理伤害。
A.正确
B.错误
[多项选择]关于市场机会的分类,主要包括( )。
A. 整体市场机会和局部市场机会
B. 环境市场机会与企业市场机会
C. 边缘市场机会与行业市场机会
D. 表面市场机会与潜在市场机会
E. 目前市场机会与未来市场机会
[单选题]转赠物资的委托人取消了对捐赠物资的转赠要求,且不再收回捐赠物资的,应当将转赠物资转为单位的存货、固定资产等,同时确认( )。
A.财政拨款预算收入
B.其他收入
C.投资收益
D.事业预算收入
[单项选择]X射线在空间某一点的强度是指单位时间内通过垂直于X射线传播方向上的单位面积上的光子数量与能量乘积的总和。可见,X射线强度是由光子数目和光子能量两个因素决定的。在医学应用中,常用X射线的量和质来表示X射线的强度。以下描述正确的是()
A. 单能X射线的强度Ⅰ与光子能量成反比
B. 单能X射线的强度Ⅰ与光子数目成正比
C. 单能X射线的强度Ⅰ与光子数目成反比
D. 单能X射线的强度Ⅰ与光子数目无关
E. 在X射线能谱中,曲线下所包括的总面积代表X射线的能量
[判断题]保险粉发生燃烧时可用水扑灭。( )
A.正确
B.错误
[多项选择]建筑装饰装修材料按照其材质的不同,可以分为()。
A. 有机和无机纤维类
B. 有机复合材料
C. 无机胶凝材料类
D. 无机复合材料类
E. 地面装饰材料
[判断题]作业许可证的有效期限一般不超过一个班次(8小时),办理许可证延期一般不得超过24小时。临时用电作业许可证的有效期限最长不能超过15日。
A.正确
B.错误
[单选题]现在车统计是反映车站、局管内及新线、合资、地方铁路内每日18点( )。
A.货车现在数
B.货车的现在数及运用情况
C.货车数
D.货车、客车数
[判断题]站长室无人时,空调、照明等电源应可以处于常开状态。
A.正确
B.错误
[单选题]小概率事件的频率是( )
A. P≤0.05
B. p≤0.02
C. p≤0.005
D. p≤0.002
[填空题]对于一个具有n个结点的单链表,在已知p结点后插入一个新结点的事件的时间复杂性为______,在给定值为x的结点后插入一个新结点的时间复杂性为______。
[判断题]发生旅客人身伤害或急病时,车站或列车应会同公安人员勘察现场,收集旁证、物证,调查事故发生原因,编制旅客伤亡事故记录并积极采取抢救措施。
A.正确
B.错误
[多选题]事故发生单位的()在事故调查期间,不得擅离职守,应当随时接受事故调查组询问。如实提供情况或资料。
A.负责人
B.分管负责人
C.安全管理人员
D.有关人员
[单选题]水源手册主要包括辖区消防水源的种类.数量.分布和( )等。
A.管网.管径
B.管网
C.管径
D.流量
[单选题]下列项目中,必须进行招标的项目是( )。
A.需要采用不可替代的专利的项目
B.使用外国政府贷款、援助资金的项目
C.采购人依法能够自行建设的项目
D.无关社会经济、安生的大型基础设施项目
[单选题]09版智能电能表出现故障时,显示出错代码Err-06的故障为(____)。
A.卡内初始化错误
B.时钟故障
C.过载
D.存储器故障或损坏
[判断题]使用钳形电流表测量低压线路和配电变压器低压侧电流,应注意不触及其他带电部位,以防接地短路。
A.正确
B.错误
[判断题]凡未经检查或不合格的电气产品一律不得安装使用。( )
A.正确
B.错误
[单项选择]任务分解时,()方法从特殊到一般的方向进行,首先定义一些特殊的任务,然后将这些任务组织起来,形成更高级别的WBS层。
A. 模板参照
B. 自顶向下
C. 类比
D. 自底向上
[单选题]依据《中国南方电网有限责任公司电气操作导则》(2017),关于断路器及负荷开关操作原则,以下说法错误的是
A.断路器分闸操作时,若发现断路器非全相分闸,可不经值班调度员命令立即合上该断路器;断路器合闸操作时,若发现断路器非全相合闸,可不经值班调度员命令立即拉开该断路器
B.断路器分(合)闸操作时,若发生断路器非全相分(合)闸,应立即检查三相不一致等相关保护动作情况并汇报值班调度员,由值班调度员依据断路器闭锁分闸故障处置原则指挥处理,尽快消除三相不平衡电流,并隔离故障断路器
C.断路器控制电源、保护电源必须待其回路有关隔离开关全部操作完毕后才能退出,以防止误操作时失去控制电源和保护电源
D.断路器允许断开、合上额定电流以内的负荷电流及切断额定遮断容量以内的故障电流
[单项选择] Information is the primary commodity in more and more industries today.
By 2005, 83% of American management personnel will be knowledge workers. Europe and Japan are not far behind.
By 2005, half of all knowledge workers (22% of the labour force) will choose "flextime, flexplace" arrangements, which allow them to work at home, communicating with the office via computer networks.
In the United States, the so-called "digital divide" seems to be disappearing. In early 2000, a poll found, that, where half of white households owned computers, so did fully 43% of African-American households, and their numbers were growing rapidly. Hispanic households continued to lag behind, but their rate of computer ownership was expanding as well.
Company-owned and industry-wide television networks are bringing programming to thousands of locations. Business TV is becoming big business.
Computer competence will approach 100% in US urban areas by the year 2005, with Europe and
A. American management personnel.
B. European management personnel.
C. American people’’s choice of career.
D. traditional practice at work.
[单选题]危化品车辆夜间禁止通行高速公路的时间段为。( )
A.0-5点
B.2-5点
C.0-6点
D.2-6点
[单选题]压阻式变送器是利用半导体的( )效应。
A.应变
B.压电
C.压阻
D.电容
[单项选择]全拼或简拼汉字输入法的编码属于______。
A. 音码
B. 形声码
C. 区位码
D. 形码
[单选题]关于GOOSE,下述说法不正确的是( )。
A.代替了传统的智能电子设备之间硬接线的通信方式
B.为逻辑节点间的通信提供了快速且高效可靠的方法
C.基于发布/订阅机制基础上
D.GOOSE报文经过TCP/IP协议进行传输
[单项选择]开始投资1000万元,从第二年开始,其年收入为固定的600万元,经济寿命为5年,当年利率i从10%增加到15%时,该项目的净现值会( )。
A. 变大
B. 变小
C. 先变大后变小
D. 先变小后变大
[多项选择]对于苯的代谢解毒,脂肪的影响是促进苯()
A. 吸收
B. 生物转运
C. 分解
D. 排泄
E. 体内蓄积
[单选题]线路允许速度vmax≤120km/h正线及到发线,50 kg/m钢轨头部垂直磨耗量超过( )mm时为轻伤钢轨。
A.8
B.10
C.12
D.14
[判断题]使用手提式灭火顺序为:拔出铁销子拉环、将喷嘴对住火源根部、人站在上风头、用手压住提手(压手)、这时灭火剂即可喷出。
A.正确
B.错误
[单选题]由供货方负责供货建筑材料,交货期限应以()为准。
A.采购方收货戳记的日期为准
B.供货方按合同规定通知的提货日期
C.供货方发运产品时承运单位签发的日期
D.采购方向承运单位提出申请的日期
[不定项选择题]共用题干
第一篇
Plant Gas
Scientists have been studying natural sources of methane(甲烷,沼气)for decades but hadn't regarded plants as a producer, notes Frank Keppler, a geochemist(地球化学家)at the Max Planck Institute for Nuclear Physics in Heldelberg,Germany. Now Keppler and his colleagues find that plants,from grasses to trees,may also be sources of the greenhouse gas.This is really surprising, because most scientists assumed that methane production requires an oxygen-free environment.
Previously,researchers had thought that it was impossible for plants to make significant amounts of the gas. They had assumed that microbes(微生物)need to be in environments without oxygen to produce methane.Methane is a greenhouse gas, like carbon dioxide.Gases such as methane and carbon dioxide trap heat in Earth's atmosphere and contribute to global warming.
In its experiments, Keppler's team used sealed chambers(室,房间;腔)that contained the same concentration of oxygen that Earth's atmosphere has.They measured the amounts of methane that were released by both living plants and dried plant material,such as fallen leaves.
With the dried plants,the researchers took measurement at temperatures ranging from 30 degrees Celsius to 70 degrees
C.At 30 degrees
C.,they found,a gram of dried plant material released up to 3 nanograms(微克)of methane per hour(One nanogram is a millionth of a gram). With every 10-degree rise in temperature,the amount of methane released each hour roughly doubled.
Living plants growing at their normal temperatures released as much as 370 nanograms of methane per gram of plant tissue per hour. Methane emissions tripled when living and dead plant was exposed to sunlight.
Because there was plenty of oxygen available,it's unlikely that the types of bacteria(bacterium的复数,细菌)that normally make methane were involved. Experiments on plants that were grown in water rather than soil also resulted in methane emissions.That's another strong sign that the gas came from the plants and not soil microbes.
The new finding is an"interesting observation,"says Jennifer Y. King,a biogeochemist(生物地球化学家)at the University of Minnesota in St. Paul. Because some types of soil microbes consume methane,they may prevent plant-produced methane from reaching the atmosphere.Field tests will be needed to assess the plant's influence,she notes.
What was scientists' understanding of methane?
A.It was produced from plants.
B.It was not a greenhouse gas.
C.It was produced in oxygen-free environments.
D.It traps more heat than any other greenhouse gas.
[简答题](201)相对挥发度aAB是什么量的函数?它受温度变化的影响如何?
[单选题]《砌体结构工程施工质量验收规范》GB50203-2011规定:填充墙砌体砌筑,应待承重主体结构检验批验收合格后进行。填充墙与承重主体结构间的空(缝)隙部位施工,应在填充墙砌筑()天后进行。
A.7
B.28
C.14
D.15