三合板板厂为什么用到尿素?

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问题:

三合板板厂为什么用到尿素?

考点:自然科学知识竞赛化学常识化学常识题库
题型:问答题 简答题

柜员轮岗换岗、休假、离职应履行有关审批手续,并按要求办理交接。

题型:问答题 简答题

下列物质的用途,主要利用物质的化学性质的是(  )

A.用氧气抢救生命垂危的病人

B.用铜做导线

C.用氦气填充探空气球

D.用铁制成锅

题型:问答题 简答题

如图所示,从图钉的构造来看,钉帽的面积做得很大是为了使用时对手指

A.增大压强

B.减小压强

C.增大压力

D.减小压力

题型:问答题 简答题

任务型填空。

     People who are concerned about pollution will be happy to know that clean and renewable energy sources

that protect the environment such as solar energy are becoming possible alternatives.

     Increasing demand for clean, renewable energy is driving a growing market for solar energy products..

Two of the main types of products that take advantage of solar energy are passive and active solar products.

These two types of systems differ in how they are constructed and can also differ greatly in cost. Passive solar

technology can be used to heat air or water directly using the sun's energy. Unlike an active solar application,

passive solar set-ups accomplish their task without the use of additional electrical components, such as fans

that need an external electricity supply. Some solar space heating or water heating systems are active solar

heating systems that have various components that call for external power sources. Because of their simplicity

compared with active systems, passive solar heating systems generally are cheaper than active ones.

     In addition to these solar heating systems, there are also solar power system available. Rather than using the

sun's energy for heating applications, these systems change solar energy into electricity. An important part of

these products is called photovoltaic cells, which generate electricity from light. As sunlight falls on a

photovoltaic cell, the light's energy is changed into electricity that can then be used to power many kinds of

electronic devices. Because of the complicated technology involved, these kinds of solar power systems can

be very expensive.

     When considering what kind of solar heating or power system to install (安装) in your home or business,

be sure to purchase your equipment from a reputable manufacturer who will be able to help you with any

necessary repair.

                                                          Solar energy application

题型:问答题 简答题

支原体肺炎,X线的特点主要是

A.内中带,中下野,小点片状阴影

B.大小不等片状阴影,融合成大病灶

C.肺纹理增强及肺气肿

D.肺下部呈去雾状浸润影,有游走性

E.多发性脓肿,脓胸,脓气胸

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