下列实验操作和处理方法可能会引发安全事故的是( ) ①将水沿着烧杯内壁缓慢加入浓

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问题:

下列实验操作和处理方法可能会引发安全事故的是(  )

①将水沿着烧杯内壁缓慢加入浓硫酸中,并用玻璃棒不断搅拌

②给试管中的液体加热时,试管口不朝向任何人

③夜间厨房发生煤气泄漏时,立即开灯检查煤气泄漏原因,并打开所有门窗通风

④用氢气还原氧化铜时,先加热氧化铜,再通入氢气.

A.①②③

B.①③④

C.②③④

D.①②③④

考点:测容器—量筒称量器—天平加热器皿—酒精灯常见仪器和装置的用途
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用于长期贮藏的果实最好是在食用品质最佳的时候采收。

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根据我国仲裁法的规定,下列关于仲裁机构组织性质及其管辖的表述中正确的是:

A.仲裁机构是实行地域管辖的民间性组织

B.仲裁机构是独立于行政机关的民间性组织,仲裁委员会相互之间也无隶属关系

C.仲裁机构是隶属于各省、市、自治区法制局的行政性组织,实行地域管辖

D.仲裁机构是实行级别管辖的民间性组织,行政上不隶属任何行政机关

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已知某企业的生产函数为,则该企业生产处于:()

A.规模收益递增阶段

B.规模收益不变阶段

C.规模收益递减阶段

D.边际收益递减阶段

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阐述产生焊接应力和变形的原因。如何防止和减小焊接变形?

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You’ve had a problem, you’ve thought about it till you were tired, forgotten it and perhaps slept on it, and then flash! When you weren’t thinking about it suddenly the answer has come to you, as a gift from the gods.

Of course all ideas don’t come like that, but the interesting thing is that so many do, particularly the most important ones. They burst into the mind, glowing with the heat of creation. How they do is a mystery. (46) Psychology does not yet understand even the ordinary process of conscious thought, but the emergence of new ideas by a "leap in thought" is particularly intriguing, because they must have come from the somewhere. For the moment let us assume that they come from the "unconscious". (47)This is reasonable, for the psychologists use this term to describe mental processes which are unknown to the subject, and creative thought consists precisely in what was unknown becoming known.

(48) It seems that all truly creative activity depends in some degree on these signals from the unconscious, and the more highly intuitive the person, the sharper and more dramatic the signals become.

But growth requires a seed, and the heart of the creative process lies in the production of the original fertile nucleus from which growth can proceed. (49) This initial step in all creation consists in the establishment of a new unity from disparate elements, of order out of disorder, of shape from what was formless. The mind achieves this by the plastic reshaping, so derived from a new unit, of a selection of the separate elements derived from experience and stored in memory. Intuitions arise from richly unified experience.

(50) This process of the establishment of new form must occur in pattern of nervous activity in the brain, lying below the threshold of consciousness, which interacts and combines to form more comprehensive patterns. Experimental physiology has not yet identified this process, for its methods are as yet insufficiently refined, but it may be significant that a quarter of the total bodily consumption of energy during sleep goes to the brain, even when the sense organ are at rest, to maintain the activity of ten thousand million brain cells. These cells, acting together as a single organ, achieve the miracle of the production of new patterns of thought. No calculating machine can do that, for such machines can "only do what we know how to design them to do", and these formative brain processes obey laws which are still unknown.

Can any practical conclusions be drawn from the experience of genius Is there an art of thought for the ordinary person Certainly there is no single road to success; in the world of the imagination each has to find his own way to use his own gift.

(50) This process of the establishment of new form must occur in pattern of nervous activity in the brain, lying below the threshold of consciousness, which interacts and combines to form more comprehensive patterns.

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