题目内容
（请给出正确答案）
[单选题]
What type of optical fiber is used for the connection inside the M600 rack？（)
A.SC-LC
B.LC-SC
C.LC-LC
D.SC-SC
查看答案
如果结果不匹配，请 联系老师 获取答案
题目内容
（请给出正确答案）
如果结果不匹配，请 联系老师 获取答案
题目内容
（请给出正确答案）
A.SC-LC
B.LC-SC
C.LC-LC
D.SC-SC
如果结果不匹配，请 联系老师 获取答案
更多“What type of optical fiber is …”相关的问题
What properties allow plastics compete strongly with optical glasses？
A) Better wear & abrasion resistance
B) Better toughness
C) Low cost
D) Low density
Believe it or not, optical illusion (错觉) can cut highway crashes.
(78) Japan is a case in point. (79) It has reduced automobile crashes on some roads by nearly 75 percent using a simple optical illusion. Bent stripes, called chevrons (人字形), painted on the roads make drivers think that they are driving faster than they really are, and thus drivers slow down.
Now the American Automobile Association Foundation for Traffic Safety in Washington D.C. is planning to repeat Japan's success. Starting next year, the foundation will paint chevrons and other patterns of stripes on selected roads around the country to test how well the patterns reduce highway crashes.
(80) Excessive speed plays a major role in as much as one fifth of all fatal traffic accidents, according to the foundation. To help reduce those accidents, the foundation will conduct its tests in areas where speed - related hazards are the greatest - curves, exit slopes, traffic circles, and bridges.
Some studies suggest that straight, horizontal bars pained across roads can initially cut the average speed of drivers in half. However, traffic often returns to full speed within months as drivers become used to seeing the painted bars.
Chevrons, scientists say, not only give drivers the impression that they are driving faster than they really are but also make a lane appear to be narrower. The result is a longer lasting reduction in highway speed and the number of traffic accidents.
The main point of the passage is ______.
A．a new way of highway speed control
B．a new approach to training drivers
C．a new pattern for painting highways
D．a new type of optical illusion
Each advance in microscopic technique has provided scientists with new perspectives on the function of living organisms and the nature of matter itself. The invention of the visible-light microscope late in the sixteenth century introduced a previously unknown realm of single celled plants and animals. In the twentieth century, electron microscope have provided direct views of viruses and minuscule surface structures. Now another type of microscope, one that utilizes X rays rather than light or electrons, offers a different way of examining tiny de tails; it should extend human perception still farther into the natural world.
The dream of building an X-ray microscope dates to 1895; its development, however, was virtually halted in the 1940's because the development of the electron microscope was progressing rapidly. During the 1940's, electron microscopes routinely achieved resolution better than that possible with a visible-light microscope, while the performance of X-ray microscopes resisted improvement. In recent years, however, interest in X-ray microscopes has revived, largely because of advances such as the development of new sources of X-ray illumination. As a result, the brightness available today is millions, of times that of X-ray tubes, which, for most of the century, were the only avail able sources of soft X-rays.
The new X-ray microscopes considerably improve on the resolution provided by optical microscopes. They can also be used to map the distribution of certain chemical elements. Some can form. pictures in extremely short times; others hold the promise of special capabilities such as three-dimensional imaging. Unlike conventional electron microscopy, X-ray microscopy enables specimens to be kept in air and in water, which means that biological samples can be studied under conditions similar to their natural state. The illumination used, so-called soft X rays in the wavelength range of twenty to forty angstroms (an angstrom is one ten-billionth of a meter), is also sufficiently penetrating to, image intact biological cells in many cases. Because of the wavelength of the X rays used, soft X-ray microscopes will never match the highest resolution possible with electron microscopes. Rather, their special properties will make possible investigations that will complement those performed with light-and-electron-based instruments.
What does the passage mainly discuss？
A．The detail seen through a microscope.
B．Sources of illumination for microscopes.
C．A new kind of microscope.
D．Outdated microscopic techniques.
What is a type of shoes that is mentioned in the passage？
A．Slippers.
B．Sandals.
C．Soles.
D．Crackowes.
A.An argumentation
B.A narrative
C.An exposition
D.None of the above
What type of eyes are found in the crab？
A．Electronic eyes.
B．Insect-shaped eyes.
C．Compound eyes.
D．Complicated eyes.
A.feedback control
B.projected control
C.definitional control
D.feedforward control
E.concurrent control
What is the main purpose of this passage？
A．To describe an experiment in which a Hydrapulper is used.
B．To introduce Hydrapulper, a new type of garbage disposer.
C．To tell what the writer thinks of the recycling of garbage.
D．To explain why garbage should be recycled in a new way.
