大學(xué)物理小抄物理4

1、專業(yè)好文檔 光的強(qiáng)度：?jiǎn)挝粫r(shí)間內(nèi)通過與光傳播方向垂直的單位面 積的光子束所具有的總能量 1、 導(dǎo)體的三種情況：1.價(jià)帶是未填滿的導(dǎo)帶（電子易從低能級(jí)向高能級(jí)躍遷）2. 價(jià)帶是滿帶，但滿帶與空帶相重疊（電子易從滿帶躍遷至空帶）3.價(jià)帶是未滿的導(dǎo)帶，又與相鄰的空帶重合2、絕緣體：價(jià)帶為滿帶，且滿帶與空帶之間的禁帶寬度較大，電子很難躍遷導(dǎo)電3、半導(dǎo)體：價(jià)帶是滿帶，滿帶與空帶之間的禁帶寬度較小。電子容易從滿帶被激發(fā)到空帶中去，從而電子和空穴都參與導(dǎo)電 4、本征半導(dǎo)體：不含任何雜質(zhì)的半導(dǎo)體，導(dǎo)電率很低。導(dǎo)電機(jī)理：電子和空穴混合導(dǎo)電。本征載流子：電子和空穴5、n型半導(dǎo)體（電子型）：施主雜質(zhì)：能向?qū)е刑峁?/p>

2、電子的雜質(zhì)。施主能級(jí)處于禁帶中，但接近導(dǎo)帶底。6、p型半導(dǎo)體（空穴型）：受主能級(jí)處于禁帶中，但接近滿帶頂7、自發(fā)輻射：處于高能級(jí)上的原子自發(fā)的向低能級(jí)躍遷而輻射出一個(gè)光子的過程8、受激輻射：在入射光的激勵(lì)下（激光）受激輻射發(fā)出的光與入射光的頻率、初相位、偏振態(tài)均相同受激吸收：在入射光的激勵(lì)下向高能級(jí)躍遷的過程9、（1）自發(fā)輻射的光波是非相關(guān)的，受激輻射的光波是相關(guān)的（2）受激輻射和受激吸收與入射光的光強(qiáng)有關(guān)（3）在熱平衡條件下，兩能級(jí)受激吸收的概率大于受激輻射的概率10、產(chǎn)生激光的必要條件：介質(zhì)中粒子數(shù)反轉(zhuǎn)（高能級(jí)原子數(shù)超過低能級(jí)原子數(shù)）。11、實(shí)現(xiàn)粒子反轉(zhuǎn)的條件：激勵(lì)能源（提供能量）；激活物

3、質(zhì)（有適當(dāng)?shù)哪芗?jí)結(jié)構(gòu)：亞穩(wěn)態(tài)）12、激勵(lì)的方法：光激勵(lì)、氣體放電激勵(lì)、化學(xué)反應(yīng)激勵(lì)、 核能激勵(lì)等。13、光學(xué)諧振腔的作用：1.產(chǎn)生并維持光振蕩，使光得到加強(qiáng)放大。2.提高激光的方向性。3.具有選頻作用，提高激光的單色性14、激光的特征：1.高定向性；2.高單色性；3.高亮度；4.極好的相干性15、世界上第一臺(tái)激光器是：紅寶石激光器。16、激光全息照相技術(shù)主要利用激光的：相干性好 無限長(zhǎng)直線 無限大平面 細(xì)圓環(huán)中軸線特別地（圓心處） 均勻帶點(diǎn)球面球內(nèi) ： 球外： 長(zhǎng)直螺線管 n：線圈密度一段直線電流螺繞環(huán)內(nèi) r到通電線圈環(huán)中心的距離無限大平面電流無限長(zhǎng)載流圓柱導(dǎo)體:1.平面載流線圈的磁矩2.均勻

4、磁場(chǎng)中載流線圈所受的磁力矩3.磁場(chǎng)中任一點(diǎn)放一個(gè)小的載流試驗(yàn)線圈可以確定該點(diǎn)的磁感應(yīng)強(qiáng)度，其大小等于放在該點(diǎn)處試驗(yàn)線圈所受的 最大磁力矩和線圈的 磁矩的比值4.磁化電流5.磁化電流的性質(zhì)：6.軟磁材料的特點(diǎn)是 磁導(dǎo)率大，矯頑力小 ，磁質(zhì)損耗低 ，它們適于用來制造 變壓器，交流電機(jī)的鐵芯 等光的波粒二項(xiàng)性對(duì)于各項(xiàng)同性介質(zhì)麥克斯韋方程組winger tuivasa-sheck, who scored two tries in the kiwis 20-18 semi-final win over england, has been passed fit after a lower-leg inju

5、ry, while slater has been named at full-back but is still recovering from a knee injury aggravated against usa.both sides boast 100% records heading into the encounter but australia have not conceded a try since josh charnleys effort in their first pool match against england on the opening day.aussi

6、e winger jarryd hayne is the competitions top try scorer with nine, closely followed by tuivasa-sheck with eight.but it is recently named rugby league international federation player of the year sonny bill williams who has attracted the most interest in the tournament so far.the kiwi - with a tourna

7、ment high 17 offloads - has the chance of becoming the first player to win the world cup in both rugby league and rugby union after triumphing with the all blacks in 2011.id give every award back in a heartbeat just to get across the line this weekend, said williams.the (lack of) air up there watch

8、mcayman islands-based webb, the head of fifas anti-racism taskforce, is in london for the football associations 150th anniversary celebrations and will attend citys premier league match at chelsea on sunday.i am going to be at the match tomorrow and i have asked to meet yaya toure, he told bbc sport

9、.for me its about how he felt and i would like to speak to him first to find out what his experience was.uefa hasopened disciplinary proceedings against cskafor the racist behaviour of their fans duringcitys 2-1 win.michel platini, president of european footballs governing body, has also ordered an

10、immediate investigation into the referees actions.cska said they were surprised and disappointed by toures complaint. in a statement the russian side added: we found no racist insults from fans of cska. baumgartner the disappointing news: mission aborted.the supersonic descent could happen as early

11、as sunda.the weather plays an important role in this mission. starting at the ground, conditions have to be very calm - winds less than 2 mph, with no precipitation or humidity and limited cloud cover. the balloon, with capsule attached, will move through the lower level of the atmosphere (the tropo

12、sphere) where our day-to-day weather lives. it will climb higher than the tip of mount everest (5.5 miles/8.85 kilometers), drifting even higher than the cruising altitude of commercial airliners (5.6 miles/9.17 kilometers) and into the stratosphere. as he crosses the boundary layer (called the trop

13、opause),e can expect a lot of turbulence.the balloon will slowly drift to the edge of space at 120,000 feet ( then, i would assume, he will slowly step out onto something resembling an olympic diving platform.they blew it in 2008 when they got caught cold in the final and they will not make the same

14、 mistake against the kiwis in manchester.five years ago they cruised through to the final and so far history has repeated itself here - the last try they conceded was scored by englands josh charnley in the opening game of the tournament.that could be classed as a weakness, a team under-cooked - but

15、 i have been impressed by the kangaroos focus in their games since then.they have been concentrating on the sort of stuff that wins you tough, even contests - strong defence, especially on their own goal-line, completing sets and a good kick-chase. theyve been great at all the unglamorous stuff that

16、 often goes unnoticed in the stands but not by your team-mates.it is as though their entire tournament has been preparation for the final.in johnathan thurston, cooper cronk, cameron smith and either billy slater or greg inglis at full-back they have a spine that is unmatched in rugby league. they have played in so many high-pressure games - a priceless asset going into saturday.the kiwis