您所在的位置:黃岡中學廣州學校 > 師生園地 > 語言文字工作專欄 > > 【國際部•教師科普】暢談雪花
                【國際部•教師科普】暢談雪花

                *此文為科普文,其中有部分內容借鑒相關書籍、資料

                 

                近日,傳來一則神奇的喜訊——南方大部分地區都降雪啦!

                雪花對于長期在陽光雨露之下成長的南方的孩子來說是新鮮的。同學們熱烈地討論著,甚至還存在著小小的期盼與幻想:廣州會不會也有機會下雪呢?如果真有那么一天,我們一定要打雪仗堆雪人!





                不過,這漫天飛舞的雪花這么好看,它究竟是如何形成的呢?這其中就涉及到很多化學知識。

                雪花是一種美麗的晶體,又名未央花和六出,是由雪晶互相碰并、粘合和鉤連在一起而形成的雪晶聚合物。目前,已知的雪花形狀大約有兩萬多種,可以說是形形色色,絢麗多姿。




                雪花的形成,首先要具備兩個條件:一是水汽飽和,另一個條件就是空氣里必須有凝結核。只有空氣中的水蒸氣附在凝結核上凝聚成水滴,才能形成降雨和降雪。

                凝結核(condensation nuclei),是物質由氣態轉化為液態或固態,或由液態轉化為固態的凝結過程中,起凝結核心作用的顆粒。這些顆粒對水分子格外具有“吸引力”,在水汽接近飽和的空氣中,水分子遇上它們,便會附著上去,并迅速聚集起來,凝結成小水滴。所以說,我們看到的雪花其實都是有“核”的。

                 

                雪花的形狀基本上以六角形為主,如六角枝狀、六角片狀等,由它們變化而來的雪花也多呈現出“六角”的特征。古人很早就發現雪花呈現六邊形,所謂“草木之花多五出,獨雪花六出”。那么,這是什么原因形成的呢?

                這主要是和水的結晶習性有關。當水結成冰的時候,由于水分子中的氫鍵作用,會有序排列形成具有一定剛性的六方形晶體結構。天然水凍結的冰和大氣中水汽凝華結晶的雪,都屬于六方晶系。其實,六方晶系就像是幾何學上的一個正六面柱體。當水汽凝華結晶的時候,如果主晶軸比其它三個輔軸發育緩慢,并且較短,那么,雪的形狀就成為六角形雪片;要是主晶軸發育很快,延伸較長,那么,雪的形狀就成為一個六個側面,一個上面和一個下面的六棱柱體。

                正是由于水分子通過化學鍵結合成六邊形的網狀結構。隨著氣溫的降低,新生的分支尖端開始變窄,并出現側向分支。冰晶遭受了交替的冷暖氣流,就會出現更多的分支,這時晶體變得又長又細。當晶體降落到更暖和的空氣中,就不再生長,尖端卻越來越寬闊,最終形成了六瓣雪花的形態。



                雪花——這冬日飛舞的精靈,呈現出千姿百態、瞬息萬變的美麗景象。

                 

                不過,在北方銀裝素裹的精致固然美麗,卻也為交通帶來了不便。于是,人們通常會將融雪劑撒在路面上以除冰除雪。那么融雪劑究竟是什么物質?它又是如何實現融雪化冰的呢?

                融雪劑,主要成份是醋酸鉀和氯鹽等化學品。當它溶于水后,相對來說,水中離子濃度會上升,從而使水的液相蒸氣壓比飽和時的蒸汽壓降低,但冰的固態蒸氣壓不變。為了使冰水混和物固液蒸氣壓相等,冰就開始融化了,其本質就是使冰雪的熔點降低。

                目前,融雪劑主要分為兩大類:一類是以“氯鹽”為主要成分的無機融雪劑,也叫“化冰鹽”,如氯化鈉(NaCl)、氯化鈣(CaCl2)、氯化鎂(MgCl2)、氯化鉀(KCl)等。其中最常用的就是是氯化鈉(即工業鹽),其價格便宜,使用方便。但是,由于鹽類遇水發生鹽漲現象,會破壞道路路基;另外,由于鹽類融雪劑和路基上的鐵等金屬形成原電池,也會加快路面破損;而且,“氯鹽”還會增加道路兩旁農田的鹽堿性,造成植被難以生長。

                另一類融雪劑,則是以醋酸鉀為主要成分的有機融雪劑,這類融雪劑融雪效果好,基本不會造成腐蝕損害, 但其成本價格較高,一般只用于機場、高爾夫球場等重要場所。

                一片小小的雪花,竟凝聚了如此眾多的化學知識。這正應了那句詩:“一粒沙里看世界,半瓣花上說人情”。也許,化學的魅力正是體現在這些細微之處,生活之中。

                【文/國際部 顧雪雅老師】

                上一條:沒有了       下一條:【愛與嚴】淺談國際部教師的職業化道路       返回上頁
                599彩票平台599彩票主页599彩票网站599彩票官网599彩票娱乐 2543jc.com | 778074.com | m35151.com | www.466890.com | 2677ddd.com | www.tushan168.com | www.55238c.com | hg999333x.com | www.40998.com | www.549377.com | 9995v.cc | www.6889781.com | 7742d.com | www.dg533.com | www.32126p.net | www.n63568.com | 168cp-i.com | www.soxi588.com | www.055520.cc | www.6491y.com | www.135.ag | 3568q.com | www.bd2019e.com | www.53900e.com | www.3569f.com | www.c6092.com | uu56988.com | www.81608t.com | e14666.com | www.jy883.com | 99988807.com | www.2605505.vip | www.340680.com | www.493365.com | www.087wy.com | 2267c.com | www.x32031.com | 1305009.com | www.938r.cc | 5004ddd.com | www.am5599.com | www.278207.com | www.cp127w.com | www.912063.com | 12742l.com | www.29178c.com | nn500r.com | www.6678685.com | 075nn.com | www.4058mm.com | 42fhyl.com | www.1168t.com | 83377e.com | www.49350.com | 61321199.com | www.61msxfpt2.com | 111122vv.com | www.623667.com | 78111199.com | www.e3410.com | 33432x.com | www.0041331.com | js07749.com | www.574546.com | 53262r.com | www.www45641.com | 2545.com | www.c1959.com | 60266.com | www.809183.com | www.pjbet444.com | www.238500.com | www.d45638.com | www.41518b.com | www.34kj.com | 56987rr.com | www.00778x.com | mmm5682.com | www.hg7022.com | mg4377.com | www.41518r.com | 6363l.com | www.786682.com | www.6020011.com | 20559944.com | www.z456x.com | ll1331.com | www.hg735.com | 91019g.com | www.44czt.com | www.63877j.com | www.424223.com | www.85886.la | 55967p.com | www.4520022.com | hd8332.com | www.717228.com | www.44221.com | 1649.com | www.81508.com | 80368e.com | www.222hy.cc | www.ylzz7770.com | 66667375.com | www.1500777.com | 07.tt | www.hf6880.com | www.55155g.com | 68228j.com | www.9b800.com | l21148com | www.08588o.com | www.882235y.com | www.217113.com | www.www-737475.com | 039da.com | www.46689.com | ss4255.com | www.046161.com | www.771049.com | 8538a.com | www.076069.com | www.81678h.com | www.88166n.com | www.twcp06.com | 32424e.com | yd12309.com | www.980158.com | www.4546600.com | www.803303.com | 496.ma | yth206.net | P35xx.com | www.916270.com | www.42456666.com | www.755.so | www.w8606.com | 78365.com | yh77.com | www.053883.com | www.71399b.com | www.5981i.com | www.hg9801199.com | yhshanghai.vip | yk117.com | www.876488.com | www.6880ff.com | www.e23012.com | www.3435b.com | 93922i.com | 22dd8332.com | www.lczg5.com | www.9570100.com | www.4901a.com | www.tushan08.com | hgyz77.com | 66681f.com | hd81366.com | www.137103.com | www.y5578.com | 0134.com | 4774b.com | www.608587.com | www.86267f.com | www.565636.com | www.pj19119.com | www.8814e5.com | 44077j.com | 66681e.com | 8890850.com | www.356387.com | www.50054k.com | www.4996xz.com | www.99291a.com | www.288msc.com | 30006n.com | 28365.com | 1434i.com | www.77996e.com | www.hqcp2.com | www.3a436.com | www.ba304.com | www.11c93.com | www.hg9509.com | www.242005.com | 272nn.net | 55545d.com | eee1915.com | 112i.net | 4869822.com | 8827xx.com | www.351731.com | www.987590.com | www.27776.cc | www.7793v.com | www.txedz.com | www.126629.com | www.848777v.com | www.667686.com | www.bet9339.com | 2268.com | 3822o.com | 2267c.com | 7508g.com | 36403388.com | ca9033.com | 25288k.com | pj88vv.com | 8037ttt.com | 3416e.com | 7003z.com | 01234lll.com | m4255.com | 3846eee.com | 8344dd.com | 159666n.com | 0332m.com | 0080u.com | ddd444000.com | 76886x.com | ppjj00.com | 1288m.com | ddd444000.com | hk6686.cc | vns8049.com | 3405w.com | 0004116.com | chinapsp.cn | x33d.vip | 2649l.com | js8800.net | 50000944.com | www.hg77848.com | www.pj11588.com | www.yun388.com | www.407776.com | www.pjbet444.com | www.2078g.com | www.hg0799.com | www.vns3600.com | www.xpj1507.com | www.hg3756.com | www.7777hx.com | www.jbs095.com | www.1168m.com | www.6663ylg.com | www.9j3.com | www.hg6688.net | www.h6630.com | www.51515m.com | www.1035s.com | www.715033.com | www.224066.com | 28hg.net | 6601.com | 22098.com | 3661yh.com | vn13588.me | www.am9977.com | www.1076008.com | www.900168.com | www.526688.com | www.4996gx.com | www.704906.com | www.32031r.com | www.1466r.com | www.88858c.com | www.aa0090.com | www.389144.com | www.c44tt.com | www.v3065.com | www.07679s.com | www.83993n.com | www.cai009.vip | www.113669.com | 33115uu.com | 1294c.cc | zhcp08.com | www.8124q.com | www.44488.cc | www.4996ln.com | www.7449cc.com | www.7793d.com | www.381860.com | h45638.com | 1104014.com | 2224001.com | 4546vip3.com | www.4887555.com | www.00773p.com | www.882918.com | www.lczg5.com | 7720o.com | l82365.com | 2146j.com | www.bet365604.com | www.365279c.com | www.wns77.me | www.hx6611.com | 2269jc.com | ii00558.com | 922630.com | www.5319tt.com | www.271998.com | www.1466h.com | www.701541.com | 2127kk.com | 38365j.com | www.pj6633.com | www.hg206.com | www.flb677.com | www.c3518.com | 5456r.com | nn40033.com | www.6491v.com | www.56655g.com | www.7886265.com | www.573667.com | chinajtw.com | s47479.com | www.z6777.com | www.63606y.com | www.c9220.com | 2698c.com | 3522g.vip | www.77537j.com | www.89599j.com | www.56666.cc | 99306d.com | 6118d.com | www.66930000.com | www.88325d.com | www.914908.com | 9995a.cc | 30006hd.com | www.js520123.com | www.55070e.com | www.10113.com | 00115003.com | 6688214app.com | www.57798b.com | www.6889771.com | www.083019.com | 8538q.com | www.21365vv.com | www.621301.com | www.956568.com | feicai0530.com | 55818b.com | www.77731h.com | www.24020.cc | 4694f.com | 88113885.com | www.7415f.com | www.am7654.com | 5555vn77.com | www.6535.com | www.63606.com | www.550134.com | 453.com | www.3643k.com | www.89386c.com | www.355711.com | 6487ccc.com | www.8888888b.com | www.7714w.com | 6137h.com | 364830.com | www.5360uu.com | www.lqc4.com | www.568001.com | www.36166v.com | 0069.com | www.3846y.com | www.qml3.com | 2566h1.com | www.0860t.com | www.pj99n.com | 6363w.com | bcrpk.com | www.295002.com | www.599546.com | 9068e.com | www.v82888.com | www.pj9030.com | 3aobo.com | 55588.com | www.hj809.com | www.60123t.com | x33o.vip | vns100.net | www.7225r.com | www.316106.com | 28288z.com | www.hemi168.com | www.hw7890.com | sha9966.com | www.88993m.com | www.33112j.com | 91019r.net | www.36677d.com | www.js1045.com | 9679a.com | www.222144.com | www.55676o.com | xpj728.com | j15hh.com | www.sss2848.com | 9339999j.com | 79889g.com | www.50685d.com | 00nn8331.com | 509191.com | www.792072.com | 0693i.com | www.81866o.com | www.90365vip.com | www.550021j.com | www.50732a.com | feicai0937.com | www.8645007.com | 3474000.com | 866666h.com | www.hr1777.com | bg7666.com | www.58777w.com | www.172323.com | 206403.com | www.368766.com | www.985jc.com | oo67890.com | www.www660882.com | www.914979.com | 0048633.com | www.tycyl.cc | www.65707a.com | 111122rr.com | www.2324.com | 4377.com | www.895095.com | www.803242.com | 655ib.com | www.55070f.com | sha9904.com | www.70088hg.com | www.99677c.com | p88818.com | www.4646123.com | www.606694.com | 111wns88.org | www.3983151.com | 0015qq.com | www.tyc600.com | www.1777ac.com | 32666k.com | www.7415e.com | ojk238.com | www.5004dd.com | www.cp8019.cc | hd6766.com | www.669112.com | 998s.cc | www.hg4799.com | www.339361.com | www.yl12007.com | www.61233pp.com | 443636.com | www.2848aaa.com | 88993b.com | www.jgj230230.com | 2400017.com | www.65476600.com | www.843552.com | 6220m.com | www.87668m.com | 76368888.cn | www.68365k.com | 1813dd.com | www.00772g.com | bet365ok02.com | www.pi111.com | 2381j.com | www.5504pj.com | www.370933.com | www.474.net | www.820933.com | www.pu5555.net | www.24czj.com | 33115ff.com | www.52072n.com | 9649m.com | www.985479.com | 53358n.com | www.hr1777.com | xpj518.com | www.7036e.com | www.0343k.com | 3355vn77.com | www.04567d.com | 76543d.com | www.89599r.com | 1222p.com | www.5981d.com | 3679kk.com | www.biying920vip.com | 83377g.com | www.4196s.com | 78930006.com | www.xpj71333.com | b7090.com | www.hg8.vip | jing26.com | www.4798.cc | 4270ww.com | www.8499t.com | 6423g.com | www.925831.com | www.11155545.com | www.296979.com | www.cr707.com | jidupt.com | www.tai444.com | 33xpj377.com | www.7225r.com | 8590.cc | www.762760.com | feicai0838.com | www.098wy.com | www.546991.com | www.389233.com | www.2404000.com | aa5443.com | www.957938.com | 58885365.com | www.68365g.com | 61322288.com | www.ya218.com | www.vns9948.com | www.55885a.com | www.217456.com | 66458y.com | www.7920w.com | 838388w.com | www.998349.com | www.0860l.com | 5757394.com | www.1064e.com | 2214hh.com | www.66376j.com | www.4123vv.com | www.135125.com | www.js888800.com | 998p.cc | www.635799.com | 9411rrr.com | www.335015.com | www.426326.com | 4997y.com | www.4923a.com | www.64400a.com | www.106167.com | www.mhcpgw.com | 9991779.com | www.66332c.com | www.849558.com | sbd023.net | www.57800q.com | 40661115.com | www.905866.com | www.pj5504.com | 2757g.com | www.7886262.com | www.68666b.com | c00351.com | www.b35zz.com | 4182001.com | www.751898.com | www.101vns.com | 55663885.com | www.77802q.com | yh22999.com | www.ycu8.com | www.078tk.com | 492dh.com | www.2222y.cc | www.xpj2025.com | 7605k.com | www.50064d.com | www.900566.com | hd9909.com | www.96386h.com | www.77537f.com | 4812g.com | www.80767h.com | www.777444o.com | 892979.com | www.720650.com | www.b30226.com | 6789blr.biz | www.dy310.com | www.00829u.com | 3156hhh.com | www.33598d.com | www.367888b.com | 26688c.net | www.917gc.com | www.66632.com | hhh67890.com | www.501251.com | www.47709.net | 500000995.com | v61653.com | www.2350.vip | www.hg7977.com | 4288e.com | www.3478h.cc | www.pj00880.com | 6261s.com | www.050236.com | www.33678ss.com | www.6033j.com | qhc52.com | www.65707m.com | www.34889.com | 4329822.com | www.106216.com | www.r999994.com | www.yh77899.com | 0981.com | www.443300a.com | www.hg173e.com | 3434ppp.com | 8890.net | www.8816i.com | www.ylg07.com | 8030g.com | x33o.vip | www.73031.cc | www.bet421.com | 55818u.com | 23800s.com | www.50024t.com | www.41427.com | 5360t.com | 3327.com | www.8667q.com | www.rycp049.com | 2649e.com | sjfygg.com | www.66ffv.com | www.8967h.com | 91019l.net | 4195l.com | www.638809.com | www.605066.com | www.a17848.com | 6654888.com | www.77114i.com | www.89777s.com | www.29ff.com | b667766.com | sbd0022.net | www.911710.com | www.83377.com | www.7111m.com | qpby2299.com | xpj718.com | www.5091m.com | www.xycp98.net | www.206365.com | 04666s.com | nnn444000.com | 38244s.com | bbbb.AG | www.26299c.com | www.o32939.com | www.22xpjdc.com | 9068r.com | 21866b.com | www.hjin5.com | www.j83377.com | 112o.net | www.8839b.com | www.sha2299.com | www.7893800.com | 7742m.com | c99345.am | www.586840.com | www.vn888456.com | www.8582uu.com | 1434f.com | mc1888.com | 88894c.com | www.912199.com | www.zzyl67.com | www.700067.com | www.hg8880.hk | 1483zz.com | 26668l.com | www.399010.com | www.7714h.com | www.98698s.com | 7893w48.com | www.624880.com | www.345311.com | www.50999k.com | www.802msc.com | 009900a.com | ddj138.com | 9411zzz.com | www.610390.com | www.pjzxyl.com | www.pj88n.com | www.9956699.com | le888c.com | hg2886.com | hgw168n.com | www.36166i.com | www.hc8878.com | www.xj1990.com | www.bwinyz17.com | www.5487.com | www.76543p.com | e2554.com | 0008ee.com | 28839i.com | www.51515v.com | www.959589.com | www.91233q.com | www.30350l.com | www.c44ff.com | www.888vip7.com | www.js522.com | 76744.com | 0011buyu.com | sbd0022.net | vv680.com | www.503477.com | www.8499r.com | www.amjs3456.com | www.bwinyz08.com | www.8222000.com | www.58777h.com | www.jinsha49.com | feicai0559.com | 3957v.com | 45939904.com | vv879101.com | 44488r.com | www.330291.com | www.ct8877.com | www.816069.com | www.78680w.com | www.4996jc.com | www.cp0017.com | www.js429.com | www.656022.com | www.617704.com | 58802g.com | 500000830.com | 6261p.com | 00212.com | i4212.com | 28839i.com | 131nn.net | z1777.com | www.083015.com | www.529979.com | www.809285.com | www.1248h.cc | www.86889.com | www.73166b.com | www.u8999.com | www.17jsc.com | www.xpj8896.com | www.w84i.com | www.4058yy.com | www.00618h.com | www.808888m.com | www.2233suncity.com | www.40789b.com | www.11731.com | www.2767t.com | www.wl6666.cc | www.hg7288.com | www.223456j.com | www.yinhecc55.com | www.pjgansu.com | www.hg60999.com | www.hhhggg.com | www.pj3234.com | www.jh879.com | www.xin2.net | www.98723.com | www.30088hg.com | www.5487567.com | www.b3652.com | www.cr1118.com | 563447.com | www.234287.com | www.394689.com | www.239644.com | www.89894f.com | 99bjlxz.com | hg77710.com | n888ok.com | 518cp-6.com | 28839i.com | 5144.com | 20160913.one | 666365.bet | 6487lll.com | 9506e.com | 553388.com | 56988r.com | www.1869h.com | www.yh04567.com | www.4938u.com | www.4107g.com | www.4261122.com | www.aomenjinsha.com | www.hy3088.com | www.k70.com | www.293988.com | www.06386677.com | www.7249n.com | www.99099hh.com | www.7793l.com | www.955484.com | www.450689.com | 29918c.com | 18299.com | hgbet.com | wns157.com | be9458.com | 99835.com | www.hg009999.com | www.hg0450.com | www.009.happy001.biz | www.983888c.com | www.20677.com | www.16065y.com | www.5091v.com | www.701269.com | www.62118e.com | 8510.com | y61.com | 4443955.com | 5004p.com | www.s27229.com | www.45966.net | www.9737ss.com | www.hh4625.com | www.08500w.com | www.590808.com | a1654.com | 2548546.com | 908080y.com | 80892nn.com | www.7111x.com | www.56655f.com | www.wns123c.com | www.80767r.com | www.866505.com | 25288y.com | yk117.com | 55331gg.com | www.hg9678.com | www.8622msc.com | www.02bet8.com | www.5856889.com | www.c5905.com | 4647.net | 3mgmqqq.com | 30006b.com | www.7111x.com | www.rycp162.com | www.47jsc.com | www.jcai4.com | 98982325.com | 759hd.com | 2373o.com | www.553843.com | www.hg6668.ph | www.66653p.com | www.390500.com | 0789.com | 33382ss.com | www.65358.com | www.98cpw.com | www.9422j.com | www.670209.com | 1168n.com | 50099.com | www.28758k.com | www.68suncitya.com | www.551108.com | www.843633.com | 2127uu.com | 999649.com | www.76543p.com | www.377838.com | www.78949f.com | www.202419.com | 8722dddd.com | 667766k.com | www.266555a.com | www.733485.com | www.fo03.com | xpj51333.com | 30019jj.com | www.7600679.com | www.w32939.com | www.08588d.com | 8381w.com | 0128765.com | 7508t.com | www.s874.vip | www.29937.com | www.914904.com | 30019e.com | 3844e.com | www.hg7602.com | www.540729.com | www.529121.com | 2v939.com | www.xsj900.com | www.DF83.com | www.9818c.cc | 4379k.com | 11ll8331.com | www.219js.com | www.428.com | www.310295.com | 80878h.com | www.8xinhao.com | www.4058x.com | www.924570.com | 156250.com | 76678.com | www.xy048.com | www.55220.com | k3405.com | 22556s.com | www.2302325.com | www.60108y.com | amjs9944.com | c86811.com | www.11099.com | www.tyc44666.com | 8381uu.com | 7788xpj.com | www.fcd666.com | www.66621q.com | 1086.com | 28483000.com | www.393222.com | www.4323w.com | 51335z.com | 65005y.com | www.cp67775.com | www.3478l.cc | 3473o.com | www.vns0600.com | www.1168k.com | www.2350i.com | 01234d.com | 2649nn.com | www.615073.com | www.6832g.com | 7605f.com | www.jinsha49.com | www.766129.com | www.541611.com | 3846ff.com | www.64566z.com | www.36166l.com | 27365.com | www.hg290.com | www.pjc88.vip | 188711.com | aobo26.com | www.kjlhc.cc | www.qml7.com | 6261b.com | www.6555567.com | www.ya2019v.com | 3559cccc.com | 5130.cc | www.14168a.com | zhcw.com | 05877.com | www.365022.bet | www.588730.com | 33111177.com | www.55526q.com | www.924177.com | 3807.com | www.bj448.com | www.0014j.com | 00jidu.com | www.k87087.com | www.07163e.com | m85323.net | www.msc66.com | www.50054h.com | 8977kk.com | www.4645555.com | www.3552k.com | 0805f.com | www.44400.cc | www.tctx2.com | 9068i.com | www.55526o.com | www.548277.com | 9694x.com | www.biying950vip.com | www.52303e.com | 7979xpj.com | www.087w.com | 6245c.com | www.dh70507.com | www.99638b.com | yh888k.com | www.8799.cc | www.853689.com | 85698z.com | www.1bet005.com | 2012vip77.com | www.86611d.com | www.6889775.com | 143547.com | www.pj7686.com | www.865065.com | 678888.vip | www.18131.com | 6423q.com | www.8882558.com | www.60339.cc | rrr67890.com | www.ggu.99233u.com | www.321537.com | bcylc7.com | www.36586666.com | xpj5590.com | www.2302321.com | www.168323.com | www.04222e.com | www.hg09b.com | P77.cc | www.92820.com | 86811j.com | www.3657a.com | www.3890w.com | qqq7570.com | www.4963s.com | 22296yy.com | www.55scweb.com | www.fcff9.com | 808vns.com | www.3032nn.com | 19991e.com | www.3165.com | www.196902.com | www.593858.com | www.66201.cc | v3405.com | www.r1432.com | 55984q.com | www.7878788.com | www.375781.com | www.7amc.com | www.89894j.com | 4255aa.com | www.n80288.com | 11tyc.com | www.d6969.com | vic040.com | www.5604q.com | www.508533.com |