Robert Hall and his colleagues, while working at General Electric’s Research and Developme

nt Center in New York, were among the first groups of researchers to report a working semiconductor laser diode in 1962.

提问人：网友hexiaodong90 发布时间：2022-01-07

参考答案

抱歉！暂无答案，正在努力更新中……

如搜索结果不匹配，请联系老师获取答案

您可能会需要：

重置密码查看订单联系客服

安装简答题APP，拍照搜题省时又省心！

更多“Robert Hall and his colleagues…”相关的问题

第1题

Being China's sixth largest export market, Wal-Mart is never exempted from the blame for killing U.S. manufacturing sector by too-cheap-to-beat Chinese imports

点击查看答案

第2题

They collected __________ from public bins around campus — even carting styrofoam and old computers to companies that could reprocess them.

点击查看答案

第3题

________ rooms on the campus were being used by holidaying families.

A、Durable

B、External

C、Vacant

D、Occasional

点击查看答案

第4题

Not too many decades ago it seemed "obvious" both to the general public and to sociologists that modem society has changed people's natural relations, loosened their responsibilities to kin and neighbors, and substituted in their place superficial relationships with passing acquaintances. However, in recent years a growing body of research has revealed that the "obvious" is not true. It seems that if you are a city resident, you typically know a smaller proportion of your neighbors than you do if you are a resident of a smaller community. But, for the most part, this fact has few significant consequences. It does not necessarily follow that if you know few of your neighbors you will know no one else.

Even in very large cities, people maintain close social ties within small, private social worlds. Indeed, the number and quality of meaningful relationships do not differ between more and less urban people. Small-town residents are more involved with kin than big-city residents. Yet city dwellers compensate by developing friendships with people who share similar interests and activities. Urbanism may produce a different style. of life, but the quality of life does not differ between town and city. Nor are residents of large communities any likelier to display psychological symptoms of stress or alienation, a feeling of not belonging, than are residents of smaller communities. However, city dwellers do worry more about crime, and this leads them to a distrust of strangers.

These findings do not imply that urbanism makes little or no difference. If neighbors are strangers to one another, they are less likely to sweep the sidewalk of an elderly couple living next door or keep an eye out for young trouble makers. Moreover, as Wirth suggested, there may be a link between a community's population size and its social heterogeneity. For in- stance, sociologists have found much evidence that the size of a community is associated with bad behavior. including gambling, drugs, etc. large-city urbanites are also more likely than their small-town counterparts to have a cosmopolitan outlook, to display less responsibility to traditional kinship roles, to vote for leftist political candidates, and to be tolerant of nontraditional religious groups, unpopular political groups, and so-called undesirables. Everything considered, heterogeneity and unusual behavior. seem to be outcomes of large population size.

Which of the following statements best describes the organization of the first paragraph?

A．Two contrasting views are presented.

B．An argument is examined and possible solutions given.

C．Research results concerning the quality of urban life are presented in order of time.

D．A detailed description of the difference between urban and small-town life is given.

点击查看答案

第5题

Universal ethics argue that there are certain universal principles that should apply to all ethical judgments.

点击查看答案

第6题

A double heterostructure semiconductor laser device has its active region buried within the device in such a way that it is surrounded by low refractive index materials rendering the active region as a waveguide.

点击查看答案

第7题

Photons from the stimulated emission can themselves further stimulate emissions leading to an avalanche of stimulated emissions and coherent photons being emitted.

点击查看答案

第8题

A buried heterostructure laser diode for telecom applications: The active layer (InGaAsP) is surrounded by the wider bandgap, lower refractive index InP material. Layers are grown on an InP substrate.

点击查看答案

第9题

The density of sates g(E) is a step-like function, and is finite at E1 and E1¢.

点击查看答案

第10题

In MQW, most of the light is in the active region.

点击查看答案