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B0 g i A o duc vA d Ao ta o DAI HOC THAI NGUYEN BUI VAN THlfiN - NGUYEN QUANG DONG GIAO TRINH VfiT IV DM CUONG (Danh cho sinh vien dai hoc chinh quy nganh Y - Dirac) DAI HOC THAI NC-UYEN TRUNG TAM HOC LIEU NHA XUAT BAN DAI HOC QUOC GIA HA N 0I s A c h d u o c x u a t b a n b c ji sir t a i t r o c u a d u A n g iA o d u c d a i h o c MUC LUC Lai noi dau: Phan thufnhat: Bai mo dau: ' CO HOC Cac khai niem dai cuomg 11 Dong hoc chat diem 14 Vecto dich chuydn 14 Van toe 15 Gia toe 17 M6t sd dang chuydn dong dac biet 20 Chuydn dong dao dong 23 Chuydn dong song 26 Song am va sieu am 29 Hieu umg Doppler va ling dung 34 Dong luc hoc chat diem - Nangluong 36 Dinh luat Niuton thur nhat 36 Dinh luat Niuton thu: hai 36 Djnh luat Niuton thti ba 37 Dinh luat bao toan dong lucrng trongco he km 38 Cong va cong suat 39 Dong nang 41 The nang 42 Dinh luat bao toan co nang trudng luc the 44 Ca hoc chat luu 46 Dac diem cua cha't luu 46 Tinh hoc cha't luu Chuong Chuong Chuong 3 Dong luc hoc ch£t luu If tuong 48 Hien tuong nhdt Ung dung 50 NHIET HOC 53 Bai md dau 53 Cac dinh luat thuc nghiem ve chat 58 Phan thurhai: Chuong 1 Thuyet dong hoc chat khf va khf ly tudng 58 Phuong trinh trang thai cua khf ly tucmg 60 Cac nguyen ly nhiet dong luc hoc 62 Chuong Nguyen ly thu: nhat cua nhiet dong luc hoc 62 Nguyen ly thu: hai cua nhiet dong luc hoc 68 Entropi va nguyen ly thur hai cua nhiet dong luc hoc 71 Chat long 81 Chuong 3: Cau tao va chuydn dong phan tir cua cha't long 81 Cac hien tuong mat ngoai cua chat long 82 Hien tuong mao dan 87 Hien tuong soi, hien tuong bay hoi 91 DIEN T I f HOC 95 Tinh dien 97 Khai niem mo dau 97 Dinh luat Coulomb 99 Dien trudng cua cac dien tfch diem 100 Dien the Hieu dien the 105 Dong dien khong doi 107 Nhung khai niem md dau 107 Nhung dai luong dac trung cua ddng dien 108 Tir trircmg dong dien khong doi 112 Thf nghiem v& tuong tac tir cua ddng dien 112 Phan thurba: Chuong 1: Chuong 2: Chuong 3: A Dinh luat Ampe ve tucmg tac ttr cua dong dien 113 Vecto cam ling tti, vecta cudng dd tti trudng 114 Cam urng dien tir 120 Thi nghiem ve hien tucmg cam ting dien tti 120 Cac dinh luat cor ban ve cam ting di6 n tti 121 Mot sd trudng hap dac biet cua cam ting dien tti 123 Dao dong dien tir - Song dien tir 125 Cac luan didm cua Macxoen 125 Su tao song dien tti Cac tfnh cha't, dac didm cua song dien tti 126 Thang song dien tti 128 QUANG HOC 129 Co sd cua quang hinh hoc - Dung cu quang hoc 131 Cac dinh luat ca ban cua quang hinh hoc 131 Dung cu quang hoc 135 Giao thoa anh sang 146 Nguyen If Huyghen - Frenen 146 Ly thuyet chung ve hien tuong giao thoa anh sang 147 Giao thoa cua hai chum tia sang 154 Ung dung hien tuong giao thoa 156 Nhi6u xa anh sang 160 Ly thuyet chung ve nhilu xa anh sang 160 Nhiiu xa cua song cau qua Id tron 162 Nhidu xa gay bdi cac song phang 165 Phan cuc anh sang 172 a Anh sang tu nhien va anh sang phan cuc Su phan cuc anh sang truyen qua ban Tuamalin day Dinh luat Malus 172 173 Phan cuc vi phan xa Dinh luat Brewster 175 Phan cuc quay tJng dung 175 Hien tuong quang dien 179 Hien tuong quang dien 179 Cac dinh luat quang dien 180 Thuyet luong tu anh sang cua Einstein va giai thich cac dinh luat quang dien 181 Su hap thu anh sang 183 Dinh luat ha'p thu anh sang 183 Ung dung quang ha'p thu phan tu 186 Kien thurc co ban ve laser 190 Khai niem ve birc xa cam urng 190 Laser va may phat tia laser 191 So lupc ve tinh cha't cua chum tia laser 192 Ung dung cua laser 193 PHONG XA VA PHONG XA SINH HOC 195 Chuong 5: Chuong 6: Chuong 7: Ph£n thurnam: Chuong 1: Phong xa va phong xa sinh hoc 197 Cac dac trung co ban cua phong xa 197 Cac phuong phap ghi phong xa 202 Tuong tac cua tia phong xa vcti vat chat 204 Cac hieu ting sinh hoc cua phong xa 207 An toan phong xa 213 Chuong 2: (Jng dung mot so ki thuat vat ly vao chan doan benh bang hinh anh Nguyen ly tao hinh chung 221 Nguyen ly tao hinh chupcat ldp 222 Chup cat ldp dung vi tmh 223 Tai lieu tham khao 221 225 Lcfi noi dau Ngay nhifng tUu cua vat ly difdc ling dung rong rai nhieu Imh vuc, d c biet Y hoc, nhifng ung dung cua Vat ly hoc nhu: sif dung cac ki thu^t vat ly chin doan va di£u tri, dien tim, dien tam dd, dien nao d , dieu tri bang nhiet, bang tif trudng, ling dung cua am va sieu am , chup X quang, sdi quang hoc md ndi soi, ting dung cua phong xa, chup hinh c£t ldp vi tinh, chup cdng hudng tir hat nhan, mat va cac dung cu quang hoc, ling dung cua anh sang dieu tri, nhifng ting dung cua laser da lam cho nganh Y - Difpc co mdt su phat trien vudt bac, giup cac thly thuoc chan doan va di£u tri chinh xac va cd hieu qua cao Giang day mdn Vat ly dai ctfdng nham trang bi cho sinh vien nganh Y Dude nhifng kien thuc vat ly cd ban nhat lien quan phuc vu nganh nghe, va trang bi cho sinh vien phudng phap tu khoa hdc, ket hdp vdi thuc tien, cung cap cac khai niem, nguyen ly, quy luat cd ban nhat cua vat ly, de? tif dd ho cd the hoc cac mdn hoc khac nhu : Hoa vd cd, Hoa - Ly, Ly sinh y hoc, Vat ly tri lieu - phuc hdi chuc nang, Chan doan hinh anh, y hoc hat nhan, va cac mdn hoc khac cd lien quan Giao trinh dude bien soan theo chuong trinh dao tao mdi xay dung cua Trudng Dai hoc Y - Dude - Dai hoc Thai Nguyen Noi dung cua tai lieu cung cap nhifng kie'n thuc cd ban ve: Cd hoc, nhiet hoc, dien hoc, quang hoc, phdng xa, hat nhan nguyen tu phuc vu nganh Y - Dude Do doi tudng dao tao chu yeu la sinh vien mien nui, nen kha n£ng tiep thu kieh thuc vat ly cd nhieu han che' Vi vay, vifc bien soan mdt giao trinh V at ly dai cifdng vifa dam bao tinh cd ban va he thong kie'n thuc, phu hdp vdi chudng trinh chung cua Bd, vifa phu hdp vdi doi tudng dao tao la mdt viec lam can thiet Giao trinh d u d e b ien soan lin d au , kha nang va kinh nghiem han che', chSc chin khdng tranh khoi thie'u sot Chung tdi rat mong nhan d u d e su gop y cua cac ban dong nghiep va cac em sinh vien de’ giao trinh cang d u d e hoan chinh hdn Xin chan cam dn! Thai Nguyen,, 27 thang n2m 2008 CAC tA c g i a 3.4.42 Entropi Id thudc mite dd hdn don cua II, ~ Entropi cung lien quan Id, su h6n ddn cua he Khi entropi tang thi muc non don cua nguyen tu cung tang Vf du Qua trinh gian no khf vao ch&n kh6ng entropi tang, su h6n don cua nguyen tu cQng tang vi trang thai moi vi trf khong gian tang len so voi truoc Boltzman da tim moi lien he giua entropi va su h6n don nguyen tu: S = K.lnW do: S la entropi cua he K la hing so Boltzman W la do mire h6n don cua he 80 (23) Chuong CHAT LONG Cau tao va chuyen dong phan tuf cua cha't long 1.1 Trang thai long cua cac chat Ngudi ta tha'y luc nhiet thap hon nhiet tdi han nao dd, neu nen manh chat khf, no se bien sang trang thai long Thuc nghiem chting to ring neu tiep tuc lam lanh cha't long se ddng dac va chuyen sang the ran Vay cd th i ndi trang thai long la trang thai trung gian giua trang thai khf va ran Tuy theo nhiet va ap suat, chat long cd tfnh cha't gan chat khf va gin chat ran nhiet gan nhiet tdi han khdng ranh gidi giua long va khf nua nhiet gan nhiet ddng dac, chat long lai cd nhieu tfnh chat tuong tu chat ran, luc dd cac phan tu lai khdng hoan toan chuyen dong hdn don ma chung sap xep tuong doi tuong tu, gan giong nhu cac tinh the chat ran Tuy nhien d trang thai binh thudng, chat long cd nhieu tfnh chat khac chat khf va chat ran, vf du : tfnh chay duoc, khdng cd hinh dang xac dinh Tfnh chat hai mat cua chat long lien quan den cau tao va chuyen dong phan tir cua no 1.2 Cau tao va chuyen dong phan tu cua chat long Ta biet rang nang luong chuyen dong nhiet cua cac phan tu chat long vao cd sau cua hd the nang Nhu vay nang luong urng vdi mot bae tu ^.kT se be hon sau cua hd, dd cac phan tu chat long khdng dich chuyen tu ma chi thuc hien cac dao dong quanh vi tri can bang Tuy nhien gia tri ^.kTkhdng nhd hon sau cua hd the nang nhieu qua, vi vay thang giang dong nang phan tti du ldn va phan tti cd the vuot qua hd the nang d l di chuyln den mot vi tri can bang mdi Ngudi ta ndi cac phan tti chat long song ddi “du muc” sau mot thdi gian “dinh cu” phan tti lai “nho leu” di 81 Then gian dao dong quanh vi tri can bang cua cha't long phu thudc vao nhiet Khi tang nhiet thdi gian giam, a nhiet dd gin nhiet dong dac, thdi gian rat ldn Nghien curu ve chuyln dong phan tu chat long, ngudi ta dung cong thtic: W T = T 0.e kT do: x : thdi gian dao dong trung binh cua phan tti quanh mot vi tri can bang k : hang so Boltzman T : nhiet tuyet doi t0 : chu ky dao dong trung binh cua phan tti quanh vi tri can bang W: nang luong hoat dong cua phan tu Vdi nude d nhiet thong thudng t =10 u giay, x0=10 n giay Nhu vay, cti dao dong khoang 100 chu ky, phan tti nude lai dich di ch6 khac Cac hien tutong m a t ngoai cua cha't long 2.1 Ap sua't phan tu Mat cau bao ve: Trong cha't long khoang cach giua cac phan tti la nho hon so vdi chat khf, vi vay luc htit phan tti dong vai trd dang ke Tuy nhien luc hut phan tti giam nhanh theo khoang each, dd chi nhung phan tti cach mot khoang nho hon 2r vao cd 10'9m mdi tac dung len Neu tti mot phan tti lam tam, ta ve mot mat cau ban kmh r thi phan tti tren chi tuong tac vdi cac phan tti nam mat cau dd Mat cau nhu vay duoc goi la mat ciu Hinh 3.1 Mat cau bao ve bao ve (hinh 3.1) Ap suat phan tu: vi tri (1), cac phan tu nam sau long chat long, mat cau bao ve cua chting nam hoan toan chat long, luc tac dung len mdi phan tti dd ve moi phia bu trti cho Doi vdi cac phan tti nam d vj tri (3), chung nam d ldp mat ngoai (cd be day nhd hon 10 9m) thi mat cau bao ve cua chung khdng hoan toan nam chat long, cd mot phan nam khdng khi, hut cac phan tti len phfa tren vdi mot luc rat yeu, khdng dang ke, cac phan tti chat long d dudi hut cac phan tu vdi mot luc ldn hon, dd lire tac dung len mdi phan tu dd khdng bu trti cho va mdi phan tti chiu mot lire tong hop hudng vao chat long Luc ep len phan chat long phia va gay 82 n6n mdt ap sua't goi la ap sua't phan tu Doi vdi nude, ap sua't phan tti co gia tri den hang van atmophe Dac diem: Mac du ap suat phan tti rat 1dm nhung no khong nen duoc cac phan tti a phfa sit lai VI cac phan tu sit lai g£n mot khoang cach nho hon r0 (r0 la khoang cach ma tai luc hut can bang vdi luc d£y) thi ltic luc diy lai chong lai ap suat phan tti va lam cho cac phan tu khong sit lai Do dd cac cha't long cd tfnh kho nen Cdn chti y rang khong the duoc ap suat phan tti vi no luon luon hudng vao long cha't long, no khong tac dung len binh va len nhung vat nhting vao cha't long 2.2 Nang lucmg mat ngoai va sure cang mat ngoai cua chat long 2.2.1 Nang luong mat ngoai cua chat long Ldp mat ngoai cua cha't long cd nhung tfnh cha't khac vdi phSn ben cua chat long Ta biet rang cac phan tti ldp ngoai bi cac phan tti a phia htit, vi vay nang lucmg cua chung ngoai dong nang chuyln dong nhiet cd the nang quy dinh boi cac luc htit dd Neu nhiet dong deu, thi nang luong trung binh chuyen dong nhiet cua cac phan tti mat ngoai va phfa giong nhau, ve the nang thi dem phan tu tti cac ldp mat ngoai, ta can thuc hien mot cdng chong lai luc hut phan tti, cdng dd cung lam tang the nang phan tu Do dd cac phan tti d ldp mat ngoai cd the nang ldn hem so vdi the nang cua cac phan tu phfa Nhu vay, cac phan tu mat ngoai cd nang lucmg t6ng cong ldn hem so vdi nang lucmg cua cac phan tti phfa Phan nang lucfng Ion hon duoc goi la nang luomg mat ngoai ciia chat long So phan tti ldp mat ngoai cang nhieu thi nang lucmg mat ngoai cang ldn , vi vay nang lucmg mat ngoai ty le vdi dien tfch mat ngoai Goi AE va A S la nang lucmg va dien tfch mat ngoai, ta cd AE = 8.AS (1) ia mot he so ty le phu thuoc cha't long goi la he so sure cang mat ngoai Trong he SI dem vi cua ia Jun tren met vuong (J/m2 = N/m) Ta biet rang mot he d trang thai can bang ben luc the nang cuc tieu, vi vay chat long d trang thai can bang ben ltic dien tfch mat ngoai cua no nhd nhat Thdng thudng tac dung cua luc nen chat long choan phan dudi cua binh chtia va mat ngoai la mat thoang nam ngang nhung neu ta khti tac dung cua luc, thi khoi chat long se cd dang hinh cau, ttic la hinh cd dien tfch mat ngoai nhd nhat cac hinh cd cung the tfch 83 Thi nghiem sau day cho ta thay dieu Bo mdt ft giot dSu vao dung dich ruou cung ty (khong hoa tan dfiu); lumig cua cac giot diu triet tieu boi stic day Acsimet nen cac giot dau co dang nhung qua cdu lo lung dung dich Hinh 3.2 Nhumg giot dau Hinh 3.3 Vong chi dang hinh tron dung dich co dang hinh cau Neu lay mot khung day thep nhung vao nude xa phong ta se duoc mot mang xa phong phu km khung Tha vao mot vong chi roi choc thung mang xa phong phfa vong chi, vong chi se trd hinh tron So dl nhu vay vi dieu kien nang luong cuc tieu nen dien tfch mang xa phong lai phai nho nhat, tuc la dien tfch thung phai ldn nhat Muon vay thi dien tfch thung phai la hinh tron, vi cac hinh cung chu vi, hinh tron cd dien tfch ldn nhat 2.2.2 Site cdng mat ngoai Cac thi nghiem tren day churng to dien tfch mat ngoai cua chat long cd khuynh hudng tu co lai, vi vay mot phuong dien nao day, mat ngoai chat long giong nhu mot¥ mang cao su bi cang De giu nguyen ' tinh trang mat ngoai cua chat long, ta phai tac dung len chu vi mat ngoai nhung luc vuong goc vdi dudng chu vi va tiep tuyen vdi mat ngoai, luc dd goi la stfc cang mat ngoai M Hinh 3.4 De tinh gia tri site cdng mat ngoai ngudi ta lam thi nghiem sau: Lay mot khung day thep cd canh MN chiiu dai bang /, cd the linh dong duoc (hinh 3.4) Nhung khung vao nude xa phong va lay ra, ta duoc mang xa phong De mang xa phong khoi co lai, can phai tac dung len MN mot luc F dung bing sue cang mat ngoai Dich chuyen canh MN mot doan Ax, dien tfch mat ngoai tang len mot luong la: AS = 2.1 Ax Sd di cd thua sd ve phai la vi mang xa phdng cd hai mat ngoai d hai phfa 84 Cdng thuc hien bai luc F dich chuyln A x la: A = F Ax Cong dung de lam tang dien tich mat ngoai len A S, turc la da lam lang nang luong mat ngoai len mot luong AE Theo (1) ta co: AE = AA =5.AS Tir ta suy ra: F = 5.2./ 21 chinh la chieu dai cua dudng kinh chu vi Trudng hop tong quat, sure cang cd thi thay d6i duoc doc theo dudng chu vi, luc dd xet mot doan A1 du nhd cua chu vi, ta ap dung pong thtic tren : AF = 6.A/ (2) Trong dd A F la sure cang tac dung len doan A / Tir (2) ta tha'y neu A / bang mot don vi chieu dai thi =AF Vi vay, cd thi dinh nghla nhu sau: He so sue cdng mat ngoai la mot dai lucmg vat ly ve tri so bang site cdng mat ngoai tac dung len mot dem vi chu vi mat ngoai Trong he SI, bang don vi Niutan/met Vdi mot cha't long cho trudc, phu thuoc nhiet do, nhiet tang thi giam Bang sau cd gia tri su:c cang mat ngoai cua mot so cha't long d 20°C Chat long d 20°C (N/m) Ni/6c 0,073 Thuy ngan 0,540 Ete 0,017 Ung dung cua hien tuong: - Gidi thich su tao lop bot chat long: Gia sir cd mot bot khdng d chat long, no se noi len mat Tdi mat chat long, bot se doi mot ldp mong cha't long cd dang hinh vom Neu bot khdng du nhd thi no khdng th i xe rach ldp mat ngoai va chiu d dudi mat chat long Nhung bot nhd nhu vay tao ldp bot - Su tao giot chat long chay qua mot IS nho: Khi chat long chay khoi mot ong thang dung thi sire cang mat ngoai, chat long khdng th i mot luc chay khoi ong Chat long chay tir tir va phia tren giot cha't long bi that lai Luc luong giot cha't long thdng sue cang mat ngoai thi chd that bi dirt va tao mot giot nude roi xuong Neu 16 rat nhd va ap sua't chat long 85 khong du ldn, giot chat long se khdng chay ngoai duoc Thi du nude mua khong chay qua duoc cac 16 nho cua vai bat Chmh di6u Y hoc ngudi ta co the la'y giot thuoc lam don vi lieu «2r Bot dudfi mat cha't 16ng Hinh 3.5 Giot cha't long khoi ong thing Hinh 3.6 2.3 Hien tirong dinh irtit va khong dinh udt Thong thucmg, dieu kien can bang thuy tmh mat thoang cua cha't long la mat nam ngang Nhung d ch6 chat long tiep xuc voi binh anh huong cua luc phan tir phia binh, mat thoang cua chat long bi cong di Goi O la diem mat thoang cham binh, tai vi tri khong nhung t6n tai luc hut phan tir cua chat long ma co luc hut phan tir cua chat ran doi vdi chat long 2.3.1 Hien tuong dinh udt Goi F, la tong cong cac luc cua cac phan tir nude tac dung len phan tir A x * nam sat binh Goi F2 la tong luc cac phan tir binh tac dung len phan tir A Trudng hop luc F2 cd gia tri ldn hon F, thi tong hop lire F hudng vao binh, chinh luc da day cac phan tir chat long xo vao binh tao mat cong lom: chat long lam udt binh Dang mat ngoai cua chat long duoc xac dinh bdi goc lam udt Dd la goc giua tiep tuyen cua be mat chat long va binh tiep xuc vdi chat long Neu < 90° : ta ndi chat long lam udt vat Vi du: nude lam udt thuy tinh, giot dau loang rong tren mat nude Neu = 0° ta ndi lam udt hoan toan 2.3.2 Hien tuong khong dinh u&t Trudng hop F2 cd tri sd be hon F, nen tong hop luc F hudng vao long chat long, luc day cac phan tir xo vao long cha't long tao mat cong loi: chat long khdng lam udt binh 86 Trong trudng hop goc > 90° Vf du thuy ngan thuy tinh goc = 169° Neu =180° Chat long khong lam udt hoan toan cha't ran Goc phu thuoc ban cha't cac cha't tiep xuc vdi nhau, phu thuoc trang thai be mat tiep xuc cha't long F, _ - _ Hien tuong lam udt va khdng lam udt thudng hay gap thuc te: Muc lam udt ngoi but nen mdi di'nh vao ngoi but, nude muakhdnglam udtmot sola cay (la mon, la khoai, sen ), ting dung ky thuat tuyen khoang de lam giau quang Hien tiTdng m ao dan ✓ 3.1 Ap suat phu dudi mat khum Nhu ta da biet mat thoang cha't long tdn tai stic cang mat ngoai nen cd the coi nhu mot mang dan hoi, dd no cd dang loi len hoac lom xuong Be mat cong cd xu hudng cd dien tfch tao mot ap sua't AP phu them vao ap sua't phan tti Trudng hop be mat cha't long la mat thoang loi (chat long khdng lam udt chat ran), dien tfch chiu tac dung cua cac luc cac phan mat thoang xung quanh keo ra, tiep tuyen mat, cd the 87 phan tich luc nam ngang va luc hucmg xuong duoi Ket qua chung la mat thoang loi chiu tac dung mot ap suat phu AP hudng xuong phia dudi Trucmg hop mat thoang lom, dien tfch chiu tac dung cua cac lire cac phan mat thoang xung quanh keo (tiep tuyen mat) co the phan tfch luc nam ngang va luc huong len tren Ket qua chung la mat thoang lom chiu tac dung mot ap suat phu huong len tren Ap suat phu AP duoc tfnh theo cong thtic: AP=— R (3) do, R la ban kfnh cua mat cong, la he so stic cang mat ngoai, Cong thtic co the chting minh nhu sau: Xet mot mat cong dang chom cau, dac trung bang ban kfnh cong R va khau kfnh r (Hinh 3.9) Xet mot phan tti AI tren chu vi C, no chiu tac dung cua mot luc cang AF, AF vuong goc voi A/ va tiep tuyen voi mat cong Tti cong thtic: AF = 5.A l Phan tfch AF hai luc phan : phan nam ngang AF2 va phan thang dting AFi Tti hinh 3.9, ta co: AF, =AF.sinP va AF2=AF.cos(3 Thanh phan AFi gay ap suat phu Tfnh stic cang len chat long bang tong cac luc A£i va co ldn: F = IAF, =!AF.sinP = Z5.A/.— = — SA/ R R Vi rang Z Al bang chu vi vong tron C, nen ta co: „ 5.r 5.27r.r2 F = — 271.r = -R R Luc phan phoi deu va ep len dien tfch chom cau la n.r2, tao ap suat phu AP Do ap sua't phu AP se la: F _ 27t.r2.5 _ 28 AP = T T =— S7= ^R.Tr.r2 R (4) Trudng hop mat khum lom: A P = -f (5) Hai cong thtic (4) va (5) co the viet chung: AP = — R 88 (6) Vdi quy udc: R > n6'u ban kfnh mat ciu huong ve phfa cha't long R < neu ban kfnh mat c£u hudmg khoi cha't long Trucmg hop mat thoang la mat phang (R = c o ) ap sua't phu AP = Y nghia ciia dp suat phu su chay ciia cha't long ong ddn hinh tru cho cha't long khong chay duoc Hien tuong bot khf can chuyen dong duoc goi la chudi hat mao quan That vay, xet mot ong dan cd bot khf ben ta tha'y: - Neu cha't long dting yen, hai ap sua't phu AP, va AP2 hudmg vao mat khum lom Neu ong tru deu thi AP,= AP2 nhung nguoc chieu (Hinh 3.10a) - Neu chat long chuyln dong (tti trai sang phai chang han) mat bj bet ra, 25 ban kfnh cong 1dm len, dd: AP, = — se be, mat lom vao, ban kfnh cong R2 R, 28 be di, dd AP2 = — se lom len AP2 cd gia tri lom hon AP, se can chuyen dong R2 cua chat long (hinh 3.10b) Tac dung can chuyen dong cang tang cd mot chudi bot (hinh 3.10c) goi la chudi hat mao quan hoac cd bot ch6 phan nhanh Tti dd ta thay cd bot khf lot vao mach mau cd the lam ngung su tuan hoan Do dd, can chti y day het bot khf trudc khf tiem thuoc vao tinh mach Tho lan trudfc len khoi mat nude phai cho ap luc khf bo lan giam tti tti neu khdng thi khf nito tan mau thoat nhanh lam phoi khong kip bai tiet se tao chudi hat mao quan ngan can su tuan hoan Nhting phi cong lai may bay o tang cao cua khf quyen neu buong lai khong km cung cd the gap tai nan tuong tu nhu tho lan K f AP, AP; AP, APj
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