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【单选题】
Although solutions to a problem are often the. fruit of direct investments in targeted research, the most revolutionary solutions tend to emerge from cross-pollination with other disciplines. Medical investigators might never have known of X rays, since they do not naturally occur in biological systems. It took a physicist, Wilhelm Conrad Rontgen, to discover them--light rays that could probe the body's interior with nary a cut from a surgeon. Here's a more recent example of cross-pollination. Soon after the Hubble Space Telescope was launched in April 1990, NASA engineers realized that the telescope's primary mirror--which gathers and reflects the light from celestial objects into its cameras and spectrographs-had been ground to an incorrect shape. In other words, the billion-and-a-half-dollar telescope was producing fuzzy images. As if to make lemonade out of lemons, though, computer algorithms came to the rescue. Investigators developed a range of clever and innovative image-processing techniques to compensate for some of Hubble's shortcomings. Tums out, maximizing the amount of information that could be extracted from a blurry astronomical image is technically identical to maximizing the amount of information that can be extracted from a mammogram. Soon the new techniques came into common use for detecting early signs of breast cancer. In 1997, for Hubble's second servicing mission, shuttle astronauts swapped in a brand-new, high-resolution digital detector-designed to the demanding specs of astronomers whose careers are based on being able to see small, dim things in the cosmos. That technology is now incorporated in a minimally invasive, low-cost system for doing breast biopsies, the next stage after mammograms in the early diagnosis of cancer. Today, cross-pollination between science and society comes about when you have ample funding for ambitious, long-term projects. America has profited immensely from a generation of scientists and engineers who, instead of becoming lawyers or investment bankers, responded to a challenging vision posed in 1961 by President John F. Kennedy. 'We intend to land a man on the Moon,' proclaimed Kennedy, welcoming the citizenry to aid in the effort. That generation, and the one that followed, was the same generation of technologists who invented the personal computer. Bill Gates, co-founder of Microsoft, was thirteen years old when the U. S. landed an astronaut on the Moon Steve Jobs, co-founder of Apple Computer, was fourteen. The PC did not arise from the mind of a banker or artist or professional athlete. It was invented and developed by a technically trained workforce, who had responded to the dream unfurled before them, and were thrilled to become scientists and engineers. The word 'cross-pollination' (Line2, Para. ) denotes ______ .
A.
harmonious unity among diverse subject
B.
acute contradiction among diverse subjects
C.
stimulating influence among diverse subjects
D.
severe restriction among diverse subjects
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参考答案:
举一反三
【单选题】数据链路层的数据单位是
A.
B.
分组
C.
数据报
D.
【单选题】Last week the writer went to the theatre. He was ______ the theatre.
A.
to
B.
At
C.
into
D.
On
【单选题】OSI参考模型中数据链路层的单位是?
A.
B.
报文
C.
比特
D.
【单选题】Last week the writer went to the theatre. Ha was ____the theatre.
A.
to
B.
at
C.
into
D.
on
【单选题】数据链路层的数据单位是
A.
比特
B.
C.
数据包
D.
数据报
【单选题】Last week the writer went to the theatre. He was ______ the theatre.
A.
to
B.
at
C.
into
D.
On
【单选题】物理层和数据链路层的单位分别是( )。
A.
比特,包
B.
包,帧
C.
比特,帧
【判断题】在数据链路层中,帧是数据链路层的传送单位。( )
A.
正确
B.
错误
【单选题】数据链路层的数据单位是?
A.
比特
B.
字节
C.
D.
分组
【单选题】数据链路层的单位是
A.
B.
C.
D.
参考解析:
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