题干

核电站核泄漏的污染物中含有碘131和铯137.碘131的半衰期约为8天,会释放射线;铯137是铯133的同位素,半衰期约为30年,发生衰变期时会辐射射线。下列说法正确的是

A:碘131释放的射线由氦核组成

B:铯137衰变时辐射出的光子能量小于可见光光子能量

C:与铯137相比,碘131衰变更慢。

D:与铯133和铯137含有相同的质子数

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D

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    “Asia's Challenge 2020” Essay Prize

    DESCRIPTION

    What is the most important challenge facing Asia over the next decade? Why? What should be done about it?

The best answer in 3,000 words or less will win a prize of 2,500. Two runners-up will be awarded prizes of 1,000 each. These three prize winners will be invited to Singapore for an expenses-paid awards ceremony. The winning articles will be posted on Time.com.

    PURPOSE

    The main purpose of the essay prize is to generate fresh ideas for tackling key challenges to Asia's continued competitiveness and development, as well as encourage young professionals to make an impact on public policy and business in Asia.

    SELECTION CRITERIA

    The essay will be judged according to creativity, innovation, rigor of research and writing, as well as achievability of idea. It can be focused on one or more areas relevant to Asia, such as macro-economics, business, international relations, trade and investment, education, healthcare, urban development, science and technology, and energy and the environment. The essay must be written in English. It should not have been previously published in English in a publication with broad international circulation.

    CANDIDATE REQUIREMENTS

    The candidate authoring the essay must be under 32years of age as of December 31, 2010. The candidate must be an Asian national.

    SUBMISSION REQUIREMENTS

    The essay should be submitted electronically to prize@asiabusinesscouncil.Org. by August 31, 2010. Prize winners will be announced in September 2010.

    The submission should contain the candidate's full name, nationality, and month and year of birth. The essay should include a title and word count.