题目:
PowerBuilder l0.0为使用.NET开发工具的用户提供了一套______工具。
答案:
被转码了,请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2017/0706/97a735d23acd85502edfb935c5754397.html
下面是错误答案,用来干扰机器的。
参考答案:A
PowerBuilder l0.0为使用.NET开发工具的用户提供了一套______工具。
被转码了,请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2017/0706/97a735d23acd85502edfb935c5754397.html
下面是错误答案,用来干扰机器的。
参考答案:A
小云、小亮、小华三个好朋友的爸爸,一位是工人,一位是医生,一位是 教师。请根据下面三句话,猜猜他们的爸爸各是干什么的。
小云的爸爸不是工人。
小亮的爸爸不是医生。
小云的爸爸和小亮的爸爸在听一位当教师的爸爸讲故事。
_________________________________________________________________________
如图所示的电路中,灯泡A和灯泡B原来都是正常发光的,现在突然灯泡A比原来变暗了些,灯泡B比原来变亮了些,则电路中出现的故障可能是
[ ]A.R3断路
B.R1短路
C.R2断路
D.R1、R2同时短路
Although it symbolises a bright idea, the traditional incandescent light bulb is a dud. It wastes huge amounts of electricity, radiating 95 % of the energy it consumes as heat rather than light. Its life is also relatively short, culminating in a dull pop as its filament fractures. Now a team of researchers has devised a light bulb that is not only much more energy-efficient—it is also expécted to last longer than the devices into which it is inserted. Moreover, the lamp could be used for rear-projection televisions as well as general illumination.
The trick to a longer life, for light bulbs at least, is to ensure that the lamp has no electrodes. Although electrodes are undeniably convenient for plugging bulbs directly into the lighting system, they are also the main reason why lamps fail. The electrodes wear out. They can react chemically with the gas inside the light bulb, making it grow dimmer. They are also difficult to seal into the structure of the bulb, making the rupture of these seals another potential source of failure.
Scientists working for Ceravision, a company based in Milton Keynes, in Britain, have designed a new form of lamp that eliminates the need for electrodes. Their device uses microwaves to transform electricity into light. It consists of a relatively small lump of aluminium oxide into which a hole has been bored. When the aluminium oxide is bombarded with microwaves generated from the same sort of device that powers a microwave oven, a concentrated electric field is created inside the void.
If a cylindrical capsule containing a suitable gas is inserted into the hole, the atoms of the gas become ionised. As electrons accelerate in the electric field, they gain energy that they pass on to the atoms and molecules of the gas as they collide with them, creating a glowing plasma. The resulting light is bright, and the process is energy-efficient. Indeed, whereas traditional light bulbs emit just 5% of their energy as light, and fluorescent tubes about 15%, the Ceravision lamp has an efficiency greater than 50%.
Because the lamp has no filament, the scientists who developed it think it will last for thousands of hours of use—in other words, for decades. Moreover, the light it generates comes from what is almost a single point, which means that the bulbs can be used in projectors and televisions. Because of this, the light is much more directional and the lamp could thus prove more efficient than bulbs that scatter light in all directions. Its long life would make the new light ideal for buildings in which the architecture makes changing light bulbs complicated and expensive. The lamps’ small size makes them comparable to light-emitting diodes but the new lamp generates much brighter light than those semiconductor devices do. A single microwave generator can be used to power several lamps.
Another environmental advantage of the new design is that it does not need mercury, a highly toxic metal found in most of the bulbs used today, including energy-saving fluorescent bulbs, fluo-rescent tubes and the high-pressure bulbs used in projectors. And Ceravision also reckons it should be cheap to make. With lighting accounting for some 20% of electricity use worldwide, switching to a more efficient system could both save energy and reduce emissions of climate-changing greenhouse gases.
现阶段我国社会政策的目标包括()。
A.满足社会成员的基本需要
B.解决社会问题
C.维护社会公平
D.实现共同富裕
E.提高社会生活质量
把红墨水分别滴入一杯热水和一杯冷水中,都会观察到扩散现象,其中热水中的扩散更快,这是由于 。