【正文】 Those who fail ed to get i n need not have f elt disappoi nted as many of the ar tist es who should have appeared di d not e. The only f unny things we heard that evening came f rom the adver ti ser at the beginning of t he. He was obviously ve r y ner vous and f or som e minut es stood awkwar dl y befor e the m icrophone. As soon as he opened his m out h, everyone burst out l aughing. We al l know what he poor m an should have sai d, but what he act ual ly said was: This i s Seed Bir d Company. Good l adi es, eveni ng and gent lemen!39。Do you al ways catch such an ear ly tr ai n 39。 which have at t imes been si ghted are si mply st range fi sh. Occasi onal y, unusual creatur es ar e washed t o t he shore, but they are r arely caught out at sea. Some ti me ago, however, a pecul iar fi sh was caught near Madagascar . A smal l f i shing boat was car r ied mi les out to sea by the power ful fi sh as it pulled on the li ne. Reali zing t hat thi s was no or di nar y f ish, t he fi sher man made ever y ef ort not to damage i t i n any way. When it was event ualy brought t o shor e, i t was found t o be over t hi r teen feet long. I t had a head l ike a hor se, big bl ue eyes, shini ng si lver ski n, and a br ight red t ail , t he fi sh, whi ch has since been sent to a museum where i t is being examined by a scienti st , is cal ed an oar fi sh. Such creature s have rar el y been seen ali ve by man as they l ive at a dept h of si x hundr ed f et. Lesson83 Af ter the el ecti ons 大選之后 The f ormer Pr ime Mini st er, Went wort h Lane, was defeated i n the r ecent elect ions. He is now reti ri ng f rom pol it ical lif e and has gone abroad. My f r iend, Cr awley, has al ways been a f anati cal opponent of Lane39。 tim e. Even so, peopl e are goi ng to f ind i t dif fi cul t to get to wor k. But so f ar, t he publ ic has expr esed it s grati tude t o the students i n let ters t o t he Pr es. Only one or t wo peopl e have obj ect ed that the student s wi l dri ve too f ast ! Lesson85 Never too ol d to learn 活到老學(xué)到老 I have just recei ved a let er fr om m y old school i nf orm ing me that my f or mer head master , Page, wi l l be r eti ri ng next week. Pupil s of the school , ol d and new, wi l l be sendi ng him a pr esent t o mar k the occasi on. Al l those who have contr ibuted t owards t he gi ft wi l sign their names in a large album which wi l be sent t o t he headmast er39。t not ice anything unusual . I suggest, 39。 I sai d. 39。實(shí)際中可以通過(guò)線性化得到系統(tǒng)Her e and t here: they had just di scovered t hat a pr isoner had escaped. At t hat mom ent , a large bl ack car wit h f our of fi cer s inside i t, stopped at t he camp gat es. The off icers got out and t he pri soner st ood to at tenti on and salut ed as t hey passed. When t hey had gone, the dri ver of t he car came t owar ds him. The man obviously want ed to t alk. He was r at her el der ly wi t h grey hair and clear blue eyes. The pri soner felt sorr y f or hi m, but t her e was nothi ng el se he coul d do. As the man came near, the pr isoner knocked hi m t o t he gr ound wit h a shar p bl ow. Then, jumpi ng into the car, he drove of f as quickly as he could. ？ Fishermen and sail or s som etim es cl ai m to have sen m onster s in t he sea. Though people have oft en laughed at stor ies tol d by s eamen, it i s now known that many of these 39。clock tr ain t o London, 39。cl ock tr ai n, but t hat you caught the which would st il l get you to work on tim e. You see, on the mor ning of the m urder, t he 8. 0 o39。My key, 39。 按照基座的運(yùn)動(dòng)形式，主要分為三大類：直線倒立擺、環(huán)形倒立擺和平面倒立擺，每 種形式的倒立擺再按照擺桿數(shù)量的不同可進(jìn)一步分為一級(jí)、二級(jí)、三級(jí)及多級(jí)倒立擺等 [4]。為制造方便和降低成本，倒立擺的結(jié)構(gòu)尺寸和電機(jī)功率都盡量要求最小，行程限制對(duì)于倒立擺的擺起尤為突出，很容易出現(xiàn)小車的撞邊現(xiàn)象。d pr ef er t o st ay her e, 39。And you di dn39。 t o peopl e on t hei r way to wor k. This wi l r el ieve pressur e on t he tr ai ns to some extent. Meanwhi le, a num ber of universit y student s have vol unt eer ed to dr ive buses whi le the str ike l asts. Al l the young men are exper t dri ver s, but bef ore they dri ve any of t he buse s, t hey wil l have t o pass a speci al t est . The st udents ar e goi ng to take the t est i n two days39。隨著非線性科學(xué)的發(fā)展，以前的采用線性化方法來(lái)描述非線性的性質(zhì)，固然無(wú)可非議，但這種方法是很有局限性，非線性的一些本質(zhì)特征往往不是用線性的方法所能體現(xiàn)的。 answered t he pol iceman in the same tone. 39。 39。 but I l ove to hear you say i t39。 he shout ed, Lane was def eat ed in the electi ons. He has reti r ed f r om poli ti cal li f e and gone t o li ve 39。 I m ust be at work at o39。 I l ooked down and near ly fel of f the ladder when I saw a pol iceman. I imm edi at ely r egr et ed answeri ng in the way I did, but I sai d, 39。近些年來(lái)，國(guó)內(nèi)外不少專家、學(xué)者一直將它視為典型的研究對(duì)象，提出了很多控制方案，對(duì)倒立擺系統(tǒng)的穩(wěn)定性和鎮(zhèn)定問(wèn)題進(jìn)行了大量研究，都在試圖尋找不同的控制方法實(shí)現(xiàn)對(duì)倒立擺的控制，以便檢查或說(shuō)明該方法的嚴(yán)重非線性和絕對(duì)不穩(wěn)定系統(tǒng)的控制能力，其控制方法在軍工、航天、機(jī)械人領(lǐng)域和一般工業(yè)過(guò)程中都有著廣泛的用途，如精密儀器的加工、機(jī)器人行走過(guò)程中的平衡控制、火箭發(fā)射中的垂直度控制、導(dǎo)彈攔截控制、航空對(duì)接控制、衛(wèi)星飛行中的 姿態(tài)控制等方面均涉及到倒置問(wèn)題。 but I l ove to hear you say i t39。 39。 answered t he pol iceman in the same tone. 39。 (5)開(kāi)環(huán)不穩(wěn)定性倒立擺系統(tǒng)有兩個(gè)平衡狀態(tài)：垂直向下和垂直向上。目前，直線型倒立擺作為一種實(shí)驗(yàn)儀器以其結(jié)構(gòu)相對(duì)簡(jiǎn)單、形象直觀、構(gòu)件參數(shù)易于改變和價(jià)格低廉等優(yōu)點(diǎn)，已經(jīng)廣泛運(yùn)用Her e and t here: they had just di scovered t hat a pr isoner had escaped. At t hat mom ent , a large bl ack car wit h f our of fi cer s inside i t, stopped at t he camp gat es. The off icers got out and t he pri soner st ood to at tenti on and salut ed as t hey passed. When t hey had gone, the dri ver of t he car came t owar ds him. The man obviously want ed to t alk. He was r at her el der ly wi t h grey hair and clear blue eyes. The pri soner felt sorr y f or hi m, but t her e was nothi ng el se he coul d do. As the man came near, the pr isoner knocked hi m t o t he gr ound wit h a shar p bl ow. Then, jumpi ng into the car, he drove of f as quickly as he could. ？ Fishermen and sail or s som etim es cl ai m to have sen m onster s in t he sea. Though people have oft en laughed at stor ies tol d by s eamen, it i s now known that many of these 39。 (2)不確定性主要是指建立系統(tǒng)數(shù)學(xué)模型時(shí)的參數(shù)誤差、量測(cè)噪聲以及機(jī)械傳動(dòng)過(guò)