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Commuter trains are often stuffy and crowded, and they frequently fail to run on time. As if that were not bad enough, physicist Hondon published a paper that gave commuters yet another reason to feel uncomfortable. Dr. Hondon examined mobile-phone usage in enclosed spaces such as railway carriages, buses and lifts, all of which are, in essence, metal boxes. His model predicted that a large number of passengers crowded together, all talking, sending text messages, or browsing the web on their phones, could produce levels of electromagnetic radiation that exceed international safety standards. That is because the radio waves produced by each phone are reflected off the metal walls of the carriage, bus or lift. Enough radiation escapes to allow the phone to communicate with the network, but the rest fills the inside of the carriage with bouncing microwaves. This sounds worrying. However, in a paper published recently, Jaime Ferrer and Lucas Fernández-Seivane from the University of Oviedo in Spain, dispute Dr. Hondou’’s findings. They conclude that the level of radiation is safe after all. In their opinion, while each phone produces radiation that bounces around the car, the passengers absorb some of it, which has the effect of reducing the overall intensity. Dr. Hondon’’s model, in short, was valid only in the case of a single passenger sitting in an empty carriage with an active mobile phone on every seat. According to Dr. Ferrer and his colleagues, Dr. Hondon overestimated the level of electromagnetic radiation. When one is sitting on a train, they found, the most important sources of radiation are one’’s own phone, and those of one’’s immediate neighbours. The radiation from these sources far exceeds that from other phones or from waves bouncing around the carriage. And all these sources together produce a level of radiation within the bounds defined by the ICNIRP, the international body that regulates such matters. People concerned about the effects of mobile-phone radiation are unlikely to take much comfort from Dr. Ferrer’’s results. Indeed, Dr. Ferrer says he was surprised at how little research has been done in this area. Yet both Dr. Hondon’’s results and Dr. Ferrer’’s are based on mathematical models. Their models make assumptions about the physical properties of train carriages and their passengers, and both assume that the radiation is uniformly distributed rather than gathered into "hot spots". But if the debate about the safety of mobile phones is to be resolved, there must be less reliance on models, and more emphasis on hard experimental data.
A．They don’’t worry about the safety of mobile phone any more.B．They want to carry out some researches by themselves.C．They still have concerns over the mobile-phone radiation.D．They find the results of all the researches boring.
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以下关于小额支付系统说法正确的是（）。
A.小额支付系统支持7×24小时连续运行
B.批量组包
C.日切时间为每日16：00
D.净额轧差
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休闲农业目标市场策略，目标市场的选择策略通常有以下哪几种模式作为参考？（）
A.市场集中化
B.产品专门化
C.市场专门化
D.有选择的专门化
E.完全 市场覆盖
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Corrigon公司正在准备一个特殊项目的的报价。这个项目是生产35，000单位的产品。工程人员建议产品以组来生产，每组包含1，000个产品。以前的经验显示，随着经验的积累，每个单位所需要的直接人工时间将以一个稳定的百分比率而逐步减少。 估计Corrigon这个项目的总成本的最好的定量工具是（）
A. 线性规划
B. 动态规划
C. 学习曲线
D. 时间序列分析
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《安全生产法》对安全生产危险性较大的行业做出了规定，即“矿山、建筑施工单位和危险物品的生产、经营、储存单位，（）。”
A.应当配备兼职安全生产管理人员
B.应当配备专职或兼职安全生产管理人员
C.必须设置安全生产管理机构
D.应当设置安全生产管理机构或配备专职安全生产管理人员
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离心泵安装的工程内容包括（）。
A．泵的开箱检查
B．泵的清洗检查
C．泵的安装和试运转
D．发电机安装
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用碘量法测定废水溶解氧，已知废水样100.0ml；滴定时消耗0，005M硫代硫酸钠溶液24ml；求溶解氧浓度？
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下列哪种恶性肿瘤属于T细胞型淋巴瘤?
A. 浆细胞样淋巴细胞型淋巴瘤 B. 蕈样霉菌病 C. 大无核裂滤泡中心细胞型淋巴瘤 D. 非Burkitt淋巴瘤
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会议文献主要的全文获取途径是（）。
A.直接参加会议B.会议论文数据库C.互联网会议网站D.图书馆借阅
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用户来电投诉，之前有接到电话推荐套餐升级，当时自己同意了，现在又不想改套餐了，第一级节点应选择（）。
A.移动业务
B.集团业务
C.家庭业务
D.增值业务
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导致局部静脉压增高的原因有（）
A.静脉痉挛B.血管硬化C.长期输入高渗性液体D.长期输入碱性液体E.栓塞形成
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连续型随机变量X的分布函数为
则常数A,B,C的取值是( ) .
A=-1, B=1/2, C=1B . A=0, B=1/2, C=2C . A=1, B=1, C=2D . A=0, B=1, C=0
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水泥混凝土路面的填缝料必须具有不流淌、不透水，低温不缩裂，富有弹性、韧性、耐老化，并且与水泥混凝土板有较强的粘附力。
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