【導讀】太陽能是太陽內部或者表面的黑子連續(xù)不斷的核聚變反應過程產(chǎn)生的能量。軌道上的平均太陽輻射強度為1367w/㎡。地球赤道的周長為40000km，從而可計算。出，地球獲得的能量可達173000TW。在海平面上的標準峰值強度為1kw/m2，地球。類依賴這些能量維持生存，其中包括所有其他形式的可再生能源，低，而且它因地而異，因時而變，這是開發(fā)利用太陽能面臨的主要問題。些特點會使它在整個綜合能源體系中的作用受到一定的限制。173,000TW，也就是說太陽每秒鐘照射到地球上的能量就相當于500萬噸煤。上的風能、水能、海洋溫差能、波浪能和生物質能以及部分潮汐能都是來源于太陽；輸，對環(huán)境無任何污染。約能源減少污染的時代。以來，太陽能電池的技術得到非常迅速的發(fā)展，單晶硅太陽能電池的轉換效率已接近25%，多晶硅太陽能電池的轉換效率已接近20%。料內的吸收產(chǎn)生電子與空穴對。減少電極區(qū)的復合可采用將電極區(qū)的摻雜濃度提高，從而降低少數(shù)載流。電池立下汗馬功勞。

　　

【正文】 on the CD now stand at around 36,000 addressed,is not confined to sex team in Virginia is also on the lookout for sites advocating drugs,or which contain references to violence or gambling,and keeps a watch on chat rooms, services,entertainment portals— even job search and financial sites can be blocked by the program. Computer users can also refresh the address list online with the Live update feature which is used by Norton AntiVirus (which is bundled with NIS) to load the latest virus service is free for the first year but,including virus definition updates,it costs $US a year thereafter. The system is not perfect, testing found the blocking of some “questionable” sites was not to get access to a wellknown US site such as Playboy results in an immediate blocking message with a standard invitation to report an“incorrectly categorized” contrast,you could find in other countries such as New Zealand a sex site which declared itself to be“dedicated to providing sexual material,imaged,and anything a little bit unusual for sex enthusiasts all over the country.” In promising to fuse media as diverse as television,telephone munication,video games,music and data transmission,the era of digital convergence goes better than yesterday’s celebrated “information superhighway.” Yet achieving this single technology is far from are currently three major television broadcast standards,and they are all inpatible with each this is nothing pared to the many technologies supporting the Inter,each with a different bandwidth and physical problems faced in designing platforms and munication systems that will be accepted across the world can appear insuperable. Even once global standards are assured,however,a further obstacle lies in Inter is plagued by long,erratic response times because it is a pulltechnology,driven by patterns of user ,on the other hand,reverses the relationship: servers simply send information to passive users,as in television and if some form of bination between oneway television flow and interactive Inter is to be the basis of our future media,it is hard to see how it could be ,the problem of fusing Inter with television is also one of defining the services ,entertainment and relaxation appear at first to be quite different doubts remain over whether consumers will be interested in having to make the sort of mental effort associated with puting while also settling down in front of a sit. Besides the issue of consumer habits,infrastructure costs are set to be immense,and will have to be met by national states or the private sector before being passed on to do not necessarily have to be mobile phone is a good example of how something that is technologically sophisticated can almost be given away,with its cost recovered through service are then coerced through clever marketing to upgrade to newer phones with more features to reinforce their dependence. Whatever the oute,it is obvious that technology will play an increasing part in our everyday technology,digital convergence embraces the services,industrial practices and social behavior that form modern have in our hands the technology to construct the most sophisticated machines ever built,but if they are unusable,simply because of their operating instructions,then recent lessons have taught us they will not we design must be simple,reliable and this is where artificial intelligence will e in.