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What will power your house in the future? Nuclear, wind, or solar power? According to scientists at the Massachusetts Institute of Technology (MIT) in the US, it might be leaves –but artificial ones. Natural leaves are able to change sunlight and water into energy. It is known as photosynthesis (光合作用). Now researchers have found a way to imitate this seemingly simple process. The artificial leaf developed by Daniel Nocera and his colleagues at MIT can be seen as a special silicon chip (硅片) with catalysts (催化剂). Similar to natural leaves, it can split water into hydrogen and oxygen when put into a bucket of water. The hydrogen and oxygen gases are then stored in a fuel cell (电池), which uses those two materials to produce electricity, located either on top of a house or beside the house. Though the leaf is only about the shape of a poker card, scientists claimed that it is promising to be an inexpensive source of electricity in developing countries. “One can imagine villages in India and Africa not long from now purchasing an affordable basic power system based on this technology,” said Docera at a conference of the American Chemical Society. An artificial leaf is not a new idea. The first artificial leaf was invented in 1997 but was too expensive and unstable for practical use. The new leaf, by contrast, is made of cheap materials, easy to use and highly stable. In laboratory studies, Nocera showed that an artificial leaf prorotype (原型) could operate continuously for at least 45 hours without a drop in activity. The wonderful improvements come from Nocera’s recent discovery of several powerful new, inexpensive catalysts. These catalysts make the energy transformation (转换) inside the leaf more efficient with water and sunlight. Right now, the new leaf is about 10 times more efficient at carrying out photosynthesis than a natural one. Besides, the device can run in whatever water is available; that is, it doesn’t need pure water. This is important for some countries that don’t have access to pure water. With the goal to “make each home its own power station” and “giving energy to the poor”, scientists believe that the new application could be widely used in developing countries, especially in India and rural China. 小题1:Which of the following order correctly shows how the artificial leaf is used to produce electricity? a. artificial leaves split water into hydrogen and oxygen b. the hydrogen and oxygen gases are stored in a fuel cell c. the artificial leaves are put in water d. the fuel cell uses hydrogen and oxygen to produce electricity A.cbad B.cabd C.bcad D.cadb 小题2:Which of the following statements about new artificial leaves is TRUE according to the article? A.They are inexpensive but unstable. B.They are as efficient at carrying out photosynthesis as natural leaves. C.They can work only in pure water. D.They need several catalysts to help them work efficiently. 小题3:The aim of the scientists at MIT in developing the new artificial leaves is to . A.build-up more power stations in the world B.provide cheaper energy for developing countries C.offer people in developing countries access to pure water D.gain a deeper understanding of the photosynthesis process 小题4:What is the main point of the article? A.Introduction to the history of artificial leaves. B.An invention copying photosynthesis. C.Giving energy to the poor. D.A mixture of water power and solar energy.
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【单选题】王某,男性,48岁,因高热两天就诊。查体:精神萎靡,四肢末梢凉,T36.8℃,BP 70/40mmHg,右肺下背部呼吸音弱,可闻及湿性啰音,右上腹触痛(±)。你打算为该患者选用的抗菌药物是 A.   B.    C.  D. E.
A.
喹诺酮类
B.
大环内酯类
C.
氨基糖苷类
D.
三代头孢+大环内酯类
E.
一代头孢+氨基糖苷类
【单选题】解决哈希冲突的主要方法有( )。
A.
数字分析法、除余法、平方取中法
B.
数字分析法、线性探测法、再哈希法
C.
数字分析法、除余法、线性探测法
D.
线性探测法、再哈希法、链地址法
【单选题】我国劳动法的适用范围为( )。
A.
国家机关、事业组织、社会团体和其劳动者之间的关系,参照劳动法执行
B.
国家与国家机关工作人员之间的劳动关系和企业与劳动者之间的社会关系是相同的
C.
国家机关、事业组织、社会团体和与之建立劳动合同关系的劳动者,适用劳动法
D.
公务员制度由劳动法调整
【单选题】《劳动法》中权力和义务的关系是( )。
A.
相辅相成的
B.
互为条件的
C.
相互统一的
D.
辅相成的,互为条件的,相互统一的都对
【判断题】第三方物流模式的特点是,与传统的物流运作方式相比,第三方物流提供了物流配送功能。
A.
正确
B.
错误
【单选题】主控指令MC、MCR可嵌套使用,最大可编写多少次
A.
5次
B.
7次
C.
8次
D.
11次
【简答题】我国劳动法的适用范围?
【判断题】精密度是指在相同条件下,多次测定值之间相互接近的程度
A.
正确
B.
错误
【单选题】在众多国内国际跨境交易平台中,eBay,速卖通,亚马逊,敦煌网这四家的市场份额占到()以上。
A.
0.6
B.
0.7
C.
0.75
D.
0.8
【判断题】34 屋顶平面图就是屋顶外形的水平投影图。
A.
正确
B.
错误
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