• <tr id="yyy80"></tr>
  • <sup id="yyy80"></sup>
  • <tfoot id="yyy80"><noscript id="yyy80"></noscript></tfoot>
  • 99热精品在线国产_美女午夜性视频免费_国产精品国产高清国产av_av欧美777_自拍偷自拍亚洲精品老妇_亚洲熟女精品中文字幕_www日本黄色视频网_国产精品野战在线观看 ?

    Response characteristics of fiber Bragg gratings irradiated by high energy lasers

    2012-11-06 08:05:14TAOMengmengYANGPenglingLIUWeipingWUYongWUJunjieYEXisheng
    中國光學(xué) 2012年5期

    TAO Meng-meng,YANG Peng-ling,LIU Wei-ping,WU Yong,WU Jun-jie,YE Xi-sheng

    (State Key Laboratory of Laser Interaction with Matter,Northwest Institute of Nuclear Technology,Xi'an 710024,China)

    *Corresponding author,E-mail:yxschx@yeah.net

    1 Introduction

    High Energy Lasers(HELs)are crucial in industrial and scientific applications.With rapid development and upgrading of HELs such as carbon dioxide lasers,Solid State Diode-pumped Lasers(SSDPL),Chemical Oxygen-iodine Lasers(COIL)and Hydrogen-fluoride/Deuterium-fluoride lasers ( HF/DF)[1-2], the parameter measurements of those lasers are becoming an outstanding problem[3].Current measurement methods mainly include burn-in method,calorimetric method[4]and electro-optical sensor method[5].However,in these methods,most of them require complicated engineering design,and laser beams need to be blocked,split,reflected or scattered.It raises problems for HELs resistance,which is a much tougher task for the future intense laser systems[6].

    Since the appearance of Fiber Bragg Gratings(FBGs),people have been thinking about their applications in sensing.After decades of fast development,F(xiàn)BG sensors are covering a wide range of fields[7],such as geological science,civil engineering,aviation,medicine and chemistry.

    In this paper,we investigate the response characteristics of FBGs under HEL beam radiation to explore the potential application of the FBG in HEL measurement.

    2 Experiments and Simulation

    Laser radiation of the fiber leads to temperature changes,resulting in the index gradient(photo-thermal effect)and strains(thermal expansion and photo-elastic effect)[8-9].As the shift of the FBG caused by strain effect is much smaller than that directly caused by temperature change[10],only the temperature change is considered in our model.Given the small diameter of the fiber,the radial heat transfer in the fiber is negligible compared with that along the fiber[10-11].

    First,the temperature features of the FBG should be revealed.An ESPEC MT3065 incubator is used to provide the stable temperature environment,and an I-MON 512E-USB interrogation monitor is used to record the resonance wavelength shift of the FBG,the relationship between the resonance wavelength shift and the temperature change of the FBG is obtained as:

    Here the parameters used are all in SI unit.This result coincides with the statement in Ref.[10].

    For position x with a length of Δx along the fiber,when irradiated by a laser beam,the heat transfer equation should be:

    where the term 1-term 4 stand for the absorption,the heat convection with the surrounding air,thermal radiation;and the heat conduction,respectively.Descriptions of the symbols used in this paper are listed in Table 1.

    The radiation experiment setup is shown in Fig.1.The high power fiber laser is used to simulate the HEL radiation situation with a center wavelength at 1 070 nm.The FBG is written in a SMF-28 fiber with a grating region of 10 mm.In the experiment,the coating layer is removed to protect the grating region from being burned.The FBG was irradiated with different laser power densities ranging from 100 to 600 W/cm2with a laser duration of 5 s.And the laser beam is 16 mm in diameter which can cover the whole grating region of the FBG.

    Tab.1 Parameters used in this paper

    Fig.1 Schematic diagram of the FBG response experiment.The inset shows the dimension of the irradiation situation.The ASE is a broadband light source covering from 1 510 to 1 580 nm.

    Solid lines in Fig.2 record the experimental rise curves of the resonance wavelength of the FBG irradiated with different laser power densities.

    Fig.2 Experimental rise curves of the FBG irradiated with different laser power densities and their fitted lines.

    Fitting of those curves in Fig.2(shown in black dashed)with single exponential growth functions gives a same time constant τ =0.436 s,independent of the laser power density.It is suggested that the heat loss is linearly proportional to the temperature change of the FBG[10].Thus,the thermal radiation term in Eq.(2)can be approximated as proportional to the temperature change[12].

    For the sake of simplicity,take the irradiated region,including the 10 mm grating region,as a whole,thus,Δx=2R.Correspondingly,take I as the average power density irradiated on the fiber.As indicated in Ref.[11],due to the small conductivity of the fiber,the sideward fiber is hardly heated,which means the temperature of the sideward fiber can be taken as the room temperature.An effective heat loss coefficient h'is introduced and it contains the convection term and the thermal radiation term,and setting Δt→0,we get:

    It has the same form with the one in Ref.[9].At steady-state,we get:

    Solving Eq.(3),the explicit expression of T(t)is:

    Since τ =0.436 s,we get the value of the effective heat loss coefficient h'=1.15×102W/(m2·K),which is very close to the one derived in Ref.[10].

    The maximal resonance wavelength shift of the FBG under different laser power densities is presented in Fig.3 with filled squares.Linear fit indicates that the maximal resonance wavelength shift changes linearly with the laser power density with the coefficient of determination being 0.997 when the laser power density is smaller than 600 W/cm2.

    Exploiting themaximal wavelength shiftat 109 W/cm2in Fig.3,together with Eq.(6),we obtain the absorption coefficient α =2.28 ×10-3.It should be noticed that this value is measured in outdoor environment where the dust on the surface of the fiber may contribute a large part to the effective absorption coefficient.This explains the difference between this effective absorption coefficient and the one of fused silica[13].Together with those listed in Table 1,these parameters can be used to calculate the time responses of the FBG irradiated by any amount of power density and duration.

    Simulation results of the maximal resonance wavelength shift and the time response of the FBG are shown in Fig.3 and Fig.4,respectively.The experimental and simulation results agree well with each other.

    Fig.3 Maximal resonance wavelength shift under different laser power densities.

    Fig.4 Experimental and numerical time response of the FBG at different laser power densities with a duration of 5 s.

    3 Discussions

    When irradiated by HEL beams,the fiber absorbs part of the energy and gets heated.However,owing to a small absorption coefficient in the near infrared range(0.8-2 μm),and a large surface area to volume ratio,the fiber can reach equilibrium in just a few seconds,resulting in limited temperature rise.And the maximal resonance wavelength shift of the FBG changes linearly with irradiating power density in a certain range.During the experiment,one bare FBG was irradiated with a powerdensity of 6 000 W/cm2for one minute,and no damage was found in the reflective spectrum,which indicats that FBGs can withstand long period radiation of HELs and it is more suitable for long time measurement of HELs.

    However,further improvement is required for this system.As we can see in Fig.4,differences exist between experimental curves and numerical ones.The possible reason would be the instability of the beam profile during the irradiating process.In addition,in our model,we assume the absorption coefficient α and the effective heat loss coefficient h'as constants which means they don't change with the temperature.But,in fact,they are temperature-dependent values[11].This will also lead to the difference between the experiment and the simulation.

    The major concern is the non-uniform temperature distribution of the grating region caused by the Gaussian distribution of the laser beam.This leads to the chirp and broadening of the reflective spectrum[10].Fig.5 shows the spectrum evolution during laser radiation process at high power density.With multi-peaks,the interrogation monitor which generates the resonance wavelength of the FBG with a Gaussian fit of the spectrum,can't present the actual wavelength shift of the FBG.

    Fig.5 Reflective spectra of the FBG under laser irradiation measured with an Agilent 86140B Spectrum Analyzer The black solid line is the reflective spectrum of the FBG at normal state.The black dashed shows the change of the spectrum during the rise time(as shown in Fig.2).And the grey solid line is the steady state spectrum when the heat transfer of the grating region reaches equilibrium.

    To improve the system,the laser power distribution along the grating region should be smoothed,where FBG s with much shorter grating regions would be a good choice.Furthermore,the interrogation method should be perfected.Package of the FBG sensor is also determinative,which will seriously affect the stability,sensitivity and dynamic range of the FBG sensor.Future work in this field will focus on these aspects.

    4 Conclusions

    Response characteristics of FBGs irradiated by HEL beams are studied,which offers a potential method to HEL parameter measurements in the near infrared range.This system can withstand extremely strong laser radiation to offer a long-time record for the laser parameters and avoid a complicated engineering design.Given the small volume of FBG,multipoint FBG sensors or FBG arrays may provide detailed distribution information for large beam profiles of HELs.

    [1] BULAEV V D,GUSEV V S,F(xiàn)IRSOV K N,et al..High power pulse-periodical electrochemical HF laser[J].Chinese Optics,2011,4(1):26-30.

    [2] RUAN P,ZHANG L M,XIE J J,et al..Key technologies of pulsed non-chain DF lasers[J].Chinese Optics,2011,4(3):313-318.

    [3] LUKE J R,GODDARD D N,LEWIS J,et al..High energy laser diagnostic sensors[C].Proc.International Symposium on High Power Laser Ablation 2010,Santa Fe,New Maxico,USA,April 18-22,2010:861-868.

    [4] ZHANG L,SHAO B B,YANG P L,et al..Diagnosis of high-repetition-rate pulse laser with pyroelectric detector[J].Chinese Optics,2011,4(4):404-410.

    [5] ROUNDY C B.Electronic laser beam profile measurement[J].SPIE,1998,3405:768-778.

    [6] GILSE J V,KOCZERA S,GREBY D.Direct laser beam diagnostics[J].SPIE,1991,1414:45-54.

    [7] RAO Y J.Recent Progress in applications of in-fiber Bragg Grating Sensors[J].Opt.Laser Eng.,1999,31:297-324.

    [8] HILL K O,MELTZ G.Fiber Bragg grating technology fundamentals and overview[J].J.Lightwave Technol.,1997,15(8):1263-1276.

    [9] WILLAMOWSKI U,RISTAU D,WELSCH E.Measuring the absolute absorptance of optical laser components[J].Appl.Optics,1998,37(36):8362-8370.

    [10] ROGERS J A,KUO P,AHUJA A,et al..Characteristics of heat flow in optical fiber devices that use integrated thin-film heaters[J].Appl.Optics,2000,39(28):5109-5116.

    [11] SALAMON T R,ROGERS J A,EGGLETON B J.Analysis of heat flow in optical fiber devices that use micro-fabricated thin film heaters[J].Sensor Actuat.A,2001,95:8-16.

    [12] LI L,GENG J X,ZHAO L,et al..Response characteristics of thin-film-heated tunable fiber Bragg gratings[J].IEEE Photon.Tech.Lett.,2003,15(4):545-547.

    [13] RICH T C,PINNOW D A.Optical absorption in fused silica and fused quartz at 1.06 μm[J].Appl.Optics,1973,12(10):2234.

    av在线app专区| 婷婷成人精品国产| 久久久久精品人妻al黑| 午夜福利影视在线免费观看| 色婷婷av一区二区三区视频| 美女高潮到喷水免费观看| 丝袜在线中文字幕| 成人18禁高潮啪啪吃奶动态图| 欧美激情高清一区二区三区 | 丝袜在线中文字幕| 免费在线观看完整版高清| 9色porny在线观看| 老司机影院毛片| 纯流量卡能插随身wifi吗| av国产精品久久久久影院| 亚洲美女视频黄频| 天天添夜夜摸| 波多野结衣av一区二区av| 欧美 亚洲 国产 日韩一| 日韩精品有码人妻一区| 亚洲av日韩精品久久久久久密 | 黄片无遮挡物在线观看| 秋霞伦理黄片| 人人妻人人澡人人看| 亚洲人成77777在线视频| 青春草视频在线免费观看| 国产亚洲av高清不卡| 亚洲精品av麻豆狂野| 国产精品成人在线| 熟女av电影| 国产无遮挡羞羞视频在线观看| 中国国产av一级| 日本午夜av视频| 国产精品久久久人人做人人爽| 午夜福利影视在线免费观看| 满18在线观看网站| 国产精品麻豆人妻色哟哟久久| xxxhd国产人妻xxx| 免费观看人在逋| 国产亚洲av片在线观看秒播厂| av国产久精品久网站免费入址| 美女主播在线视频| 久久久精品免费免费高清| 亚洲四区av| 国产熟女午夜一区二区三区| 宅男免费午夜| 天堂俺去俺来也www色官网| av天堂久久9| 国产成人精品久久二区二区91 | 久久人人爽人人片av| svipshipincom国产片| 伊人亚洲综合成人网| 久久久久久免费高清国产稀缺| 视频区图区小说| 人人妻人人澡人人爽人人夜夜| 在线观看一区二区三区激情| 男人爽女人下面视频在线观看| 又粗又硬又长又爽又黄的视频| 男女下面插进去视频免费观看| 国产精品久久久久久精品古装| av卡一久久| 最新在线观看一区二区三区 | 亚洲伊人色综图| 国产精品欧美亚洲77777| 纵有疾风起免费观看全集完整版| 精品国产一区二区三区四区第35| 亚洲欧美激情在线| 美女福利国产在线| 自拍欧美九色日韩亚洲蝌蚪91| 色网站视频免费| 80岁老熟妇乱子伦牲交| av不卡在线播放| 校园人妻丝袜中文字幕| 少妇人妻 视频| 亚洲国产精品一区二区三区在线| a级片在线免费高清观看视频| 国产精品久久久久久久久免| 女性被躁到高潮视频| 国产免费视频播放在线视频| 高清av免费在线| 欧美激情高清一区二区三区 | 欧美精品人与动牲交sv欧美| 99精国产麻豆久久婷婷| 男女无遮挡免费网站观看| 国产无遮挡羞羞视频在线观看| 欧美日韩精品网址| 国产1区2区3区精品| 日韩av免费高清视频| 国产精品无大码| 中文字幕人妻丝袜制服| 国产成人精品福利久久| 精品亚洲成国产av| 狂野欧美激情性bbbbbb| 亚洲国产欧美网| √禁漫天堂资源中文www| 久久久精品国产亚洲av高清涩受| 狠狠婷婷综合久久久久久88av| 1024香蕉在线观看| 无遮挡黄片免费观看| 国产亚洲av高清不卡| 啦啦啦在线免费观看视频4| 久久综合国产亚洲精品| 亚洲美女视频黄频| 超色免费av| 国产精品一区二区在线观看99| 亚洲国产看品久久| 国产精品国产三级国产专区5o| 青青草视频在线视频观看| 又粗又硬又长又爽又黄的视频| 欧美日韩福利视频一区二区| 亚洲国产欧美一区二区综合| 夫妻性生交免费视频一级片| 久久天堂一区二区三区四区| 伊人久久大香线蕉亚洲五| 久久精品亚洲熟妇少妇任你| 一区二区三区四区激情视频| 精品久久久久久电影网| 在线观看免费日韩欧美大片| 国产在线视频一区二区| 青春草国产在线视频| 女性被躁到高潮视频| 一区二区三区乱码不卡18| 国产亚洲午夜精品一区二区久久| 日本wwww免费看| 亚洲一区二区三区欧美精品| 丝袜美腿诱惑在线| 国产成人精品福利久久| 亚洲精华国产精华液的使用体验| 极品少妇高潮喷水抽搐| 国产欧美日韩一区二区三区在线| 免费日韩欧美在线观看| 国产欧美日韩综合在线一区二区| 欧美人与善性xxx| 国产淫语在线视频| 91精品伊人久久大香线蕉| 免费人妻精品一区二区三区视频| 午夜福利,免费看| 精品一区二区三卡| 国产在线一区二区三区精| 狂野欧美激情性bbbbbb| 好男人视频免费观看在线| 国产欧美日韩综合在线一区二区| 美女大奶头黄色视频| 人人妻人人澡人人爽人人夜夜| 亚洲,欧美精品.| 亚洲国产精品国产精品| 老司机在亚洲福利影院| 久久综合国产亚洲精品| 天堂俺去俺来也www色官网| 亚洲婷婷狠狠爱综合网| 美女主播在线视频| 国产成人系列免费观看| 在线 av 中文字幕| 午夜免费鲁丝| 国产高清国产精品国产三级| 久久久国产一区二区| 久久这里只有精品19| 亚洲精品自拍成人| 香蕉丝袜av| 人妻一区二区av| 秋霞伦理黄片| 在线观看人妻少妇| 国产精品国产三级专区第一集| 色94色欧美一区二区| 亚洲,欧美,日韩| 亚洲国产看品久久| 三上悠亚av全集在线观看| 一区二区三区激情视频| 亚洲欧美一区二区三区久久| 午夜福利视频精品| 我的亚洲天堂| 亚洲国产中文字幕在线视频| 日韩精品有码人妻一区| 在线观看免费午夜福利视频| 久久精品亚洲av国产电影网| 在线观看免费日韩欧美大片| 日韩人妻精品一区2区三区| 欧美激情高清一区二区三区 | 中文精品一卡2卡3卡4更新| 久久久久久久久久久久大奶| 人人妻人人澡人人爽人人夜夜| 精品少妇黑人巨大在线播放| 男女床上黄色一级片免费看| 99国产精品免费福利视频| 亚洲国产看品久久| 亚洲国产看品久久| 热99久久久久精品小说推荐| 日韩精品免费视频一区二区三区| av在线app专区| 晚上一个人看的免费电影| 最近2019中文字幕mv第一页| 老司机在亚洲福利影院| 一二三四在线观看免费中文在| 99久久99久久久精品蜜桃| av卡一久久| 超碰成人久久| 久久精品亚洲熟妇少妇任你| 亚洲成人手机| 精品少妇内射三级| 午夜免费鲁丝| 欧美日韩亚洲国产一区二区在线观看 | 精品一品国产午夜福利视频| 精品国产超薄肉色丝袜足j| 老司机深夜福利视频在线观看 | 午夜影院在线不卡| 亚洲国产欧美网| 国产精品女同一区二区软件| 欧美日韩一级在线毛片| 狠狠婷婷综合久久久久久88av| 精品酒店卫生间| 亚洲精品美女久久久久99蜜臀 | a级毛片黄视频| 国产精品久久久久成人av| www.熟女人妻精品国产| 亚洲精品自拍成人| av在线观看视频网站免费| 尾随美女入室| 亚洲精品中文字幕在线视频| 9热在线视频观看99| 国产99久久九九免费精品| www.精华液| 国产激情久久老熟女| 亚洲av福利一区| 亚洲伊人久久精品综合| 一级片'在线观看视频| 制服人妻中文乱码| 久久精品久久精品一区二区三区| 午夜日韩欧美国产| 色婷婷久久久亚洲欧美| 美女国产高潮福利片在线看| 亚洲国产精品成人久久小说| 丝袜脚勾引网站| 最近2019中文字幕mv第一页| 国产亚洲av高清不卡| 97精品久久久久久久久久精品| av电影中文网址| 午夜福利影视在线免费观看| 最近2019中文字幕mv第一页| 日韩中文字幕欧美一区二区 | 国语对白做爰xxxⅹ性视频网站| 国产精品一区二区精品视频观看| 少妇人妻精品综合一区二区| 一本大道久久a久久精品| 91精品国产国语对白视频| 日韩欧美精品免费久久| 亚洲av电影在线观看一区二区三区| 多毛熟女@视频| 国产精品一国产av| 永久免费av网站大全| 日韩av不卡免费在线播放| 成年人免费黄色播放视频| 尾随美女入室| 国产不卡av网站在线观看| 国产精品麻豆人妻色哟哟久久| tube8黄色片| videos熟女内射| 国产高清国产精品国产三级| 日本wwww免费看| 两性夫妻黄色片| 老鸭窝网址在线观看| 女人久久www免费人成看片| 亚洲国产日韩一区二区| 国产精品国产av在线观看| 国产精品99久久99久久久不卡 | 极品少妇高潮喷水抽搐| 男人添女人高潮全过程视频| 日本91视频免费播放| 麻豆乱淫一区二区| 在线 av 中文字幕| 国产黄色视频一区二区在线观看| 国产av国产精品国产| 日本猛色少妇xxxxx猛交久久| 69精品国产乱码久久久| e午夜精品久久久久久久| 亚洲精品视频女| 纵有疾风起免费观看全集完整版| 亚洲av日韩在线播放| 国产成人精品久久久久久| 亚洲人成77777在线视频| 夫妻性生交免费视频一级片| 制服丝袜香蕉在线| 免费观看人在逋| 午夜福利在线免费观看网站| 蜜桃在线观看..| av视频免费观看在线观看| 国产av一区二区精品久久| 悠悠久久av| 亚洲国产精品国产精品| 女人被躁到高潮嗷嗷叫费观| 嫩草影视91久久| 亚洲综合精品二区| 综合色丁香网| 国产人伦9x9x在线观看| 亚洲欧洲日产国产| av片东京热男人的天堂| 永久免费av网站大全| 亚洲av日韩精品久久久久久密 | 熟女少妇亚洲综合色aaa.| 国精品久久久久久国模美| 捣出白浆h1v1| 下体分泌物呈黄色| 免费观看性生交大片5| 一区二区三区四区激情视频| 久久97久久精品| 丰满迷人的少妇在线观看| 久久久久人妻精品一区果冻| 久久97久久精品| 免费少妇av软件| 男女之事视频高清在线观看 | 在线观看免费午夜福利视频| 国语对白做爰xxxⅹ性视频网站| 热99久久久久精品小说推荐| 成人黄色视频免费在线看| 下体分泌物呈黄色| 国产高清不卡午夜福利| 精品一区二区三区av网在线观看 | 亚洲第一av免费看| 欧美在线一区亚洲| 少妇人妻 视频| 最近2019中文字幕mv第一页| 久久久国产精品麻豆| 国产视频首页在线观看| 天天躁狠狠躁夜夜躁狠狠躁| 久久99精品国语久久久| 97人妻天天添夜夜摸| 国产精品麻豆人妻色哟哟久久| 成人影院久久| 亚洲国产精品国产精品| 国产片特级美女逼逼视频| 在线观看国产h片| 韩国高清视频一区二区三区| 欧美日韩一区二区视频在线观看视频在线| 国产片内射在线| 国产成人欧美| 五月开心婷婷网| 可以免费在线观看a视频的电影网站 | 国产精品 欧美亚洲| 国产精品成人在线| 国产亚洲av片在线观看秒播厂| 黄色 视频免费看| 久久久国产欧美日韩av| 两个人免费观看高清视频| netflix在线观看网站| 99久久综合免费| av网站在线播放免费| 操美女的视频在线观看| 视频在线观看一区二区三区| 国产成人免费观看mmmm| 黑人欧美特级aaaaaa片| 人人澡人人妻人| 咕卡用的链子| 亚洲五月色婷婷综合| 激情五月婷婷亚洲| 91aial.com中文字幕在线观看| 亚洲av欧美aⅴ国产| 久久性视频一级片| 免费av中文字幕在线| 亚洲色图综合在线观看| xxxhd国产人妻xxx| 好男人视频免费观看在线| 99九九在线精品视频| 久久97久久精品| 精品国产国语对白av| 亚洲欧美一区二区三区久久| 悠悠久久av| 日韩欧美一区视频在线观看| 女人久久www免费人成看片| 国产精品偷伦视频观看了| 人人妻人人澡人人看| 国产精品女同一区二区软件| 97精品久久久久久久久久精品| 在线观看人妻少妇| 精品一品国产午夜福利视频| 五月开心婷婷网| 亚洲色图 男人天堂 中文字幕| 国产精品国产三级专区第一集| 亚洲美女黄色视频免费看| 超色免费av| 丝袜人妻中文字幕| 亚洲成国产人片在线观看| 欧美国产精品一级二级三级| 99久久综合免费| 亚洲精品成人av观看孕妇| 日韩精品免费视频一区二区三区| 亚洲视频免费观看视频| 国产成人精品久久久久久| 99精品久久久久人妻精品| 亚洲精品乱久久久久久| 国产1区2区3区精品| 一本久久精品| 亚洲精品一区蜜桃| 国产色婷婷99| 大香蕉久久网| 国产黄频视频在线观看| 久久ye,这里只有精品| 亚洲色图综合在线观看| 一级a爱视频在线免费观看| 巨乳人妻的诱惑在线观看| 国产成人一区二区在线| 午夜免费男女啪啪视频观看| 国产在线免费精品| 69精品国产乱码久久久| 美女扒开内裤让男人捅视频| 中文字幕高清在线视频| 久久午夜综合久久蜜桃| 一二三四中文在线观看免费高清| 热99国产精品久久久久久7| 国产精品国产三级国产专区5o| 如何舔出高潮| 高清黄色对白视频在线免费看| 搡老岳熟女国产| 国产午夜精品一二区理论片| 不卡视频在线观看欧美| 亚洲成人国产一区在线观看 | 精品国产露脸久久av麻豆| 欧美在线黄色| 在线观看一区二区三区激情| 国产又爽黄色视频| 蜜桃在线观看..| 天天添夜夜摸| 国产一区二区三区av在线| 人人澡人人妻人| 少妇人妻精品综合一区二区| 十八禁高潮呻吟视频| 日韩欧美一区视频在线观看| 黄频高清免费视频| 香蕉国产在线看| √禁漫天堂资源中文www| 久久97久久精品| 中文字幕制服av| 欧美97在线视频| 男女床上黄色一级片免费看| 一个人免费看片子| 中文字幕av电影在线播放| 观看美女的网站| 欧美日韩国产mv在线观看视频| 91精品国产国语对白视频| 九色亚洲精品在线播放| 天天躁狠狠躁夜夜躁狠狠躁| 欧美最新免费一区二区三区| 精品国产一区二区三区久久久樱花| 久久99热这里只频精品6学生| 国产精品免费视频内射| av在线app专区| 美女高潮到喷水免费观看| 亚洲一卡2卡3卡4卡5卡精品中文| 国产亚洲欧美精品永久| 国产亚洲最大av| 搡老乐熟女国产| 2021少妇久久久久久久久久久| 国产精品久久久久久久久免| 欧美亚洲日本最大视频资源| 9热在线视频观看99| 精品少妇一区二区三区视频日本电影 | 亚洲精品美女久久av网站| 欧美最新免费一区二区三区| 免费人妻精品一区二区三区视频| 最近中文字幕高清免费大全6| av不卡在线播放| 超碰97精品在线观看| 涩涩av久久男人的天堂| 亚洲人成网站在线观看播放| 免费观看人在逋| 99热国产这里只有精品6| 色视频在线一区二区三区| 欧美 日韩 精品 国产| 久久毛片免费看一区二区三区| 伊人久久国产一区二区| 黄网站色视频无遮挡免费观看| 亚洲成人国产一区在线观看 | 男女国产视频网站| 99久久99久久久精品蜜桃| 美女午夜性视频免费| 99香蕉大伊视频| 99久久99久久久精品蜜桃| 欧美在线黄色| 国产 一区精品| 精品卡一卡二卡四卡免费| 在线亚洲精品国产二区图片欧美| 九草在线视频观看| 制服人妻中文乱码| 亚洲国产毛片av蜜桃av| 日韩不卡一区二区三区视频在线| a 毛片基地| 大陆偷拍与自拍| 久久久久人妻精品一区果冻| 国产淫语在线视频| e午夜精品久久久久久久| 中文字幕制服av| 男女边摸边吃奶| 国产免费视频播放在线视频| 久久精品国产a三级三级三级| 亚洲av中文av极速乱| 国产成人a∨麻豆精品| 亚洲四区av| 国产精品二区激情视频| 在线观看免费午夜福利视频| 最近手机中文字幕大全| 性高湖久久久久久久久免费观看| 国产人伦9x9x在线观看| 亚洲国产精品成人久久小说| 另类亚洲欧美激情| 日韩不卡一区二区三区视频在线| 日韩 亚洲 欧美在线| 久久久久久久久久久免费av| 日本猛色少妇xxxxx猛交久久| 一个人免费看片子| 亚洲欧美激情在线| 免费女性裸体啪啪无遮挡网站| 2018国产大陆天天弄谢| 新久久久久国产一级毛片| av.在线天堂| 成人18禁高潮啪啪吃奶动态图| 在线观看免费视频网站a站| 亚洲激情五月婷婷啪啪| 在线观看国产h片| 亚洲国产看品久久| av片东京热男人的天堂| 久久久久久免费高清国产稀缺| av在线观看视频网站免费| 老司机深夜福利视频在线观看 | 黄色视频不卡| 国产亚洲欧美精品永久| 天天影视国产精品| 大香蕉久久成人网| 又黄又粗又硬又大视频| 97在线人人人人妻| 国产免费福利视频在线观看| 搡老乐熟女国产| 一级黄片播放器| 宅男免费午夜| 天天躁夜夜躁狠狠久久av| 丰满迷人的少妇在线观看| 丝袜在线中文字幕| 成人午夜精彩视频在线观看| 天天操日日干夜夜撸| 又粗又硬又长又爽又黄的视频| 国产精品免费视频内射| h视频一区二区三区| 欧美人与性动交α欧美精品济南到| 综合色丁香网| 黄色 视频免费看| 国产成人精品在线电影| 汤姆久久久久久久影院中文字幕| 两个人看的免费小视频| 亚洲精品中文字幕在线视频| 伦理电影大哥的女人| 最近最新中文字幕免费大全7| 一二三四中文在线观看免费高清| 97人妻天天添夜夜摸| 久久婷婷青草| 91国产中文字幕| 国产av国产精品国产| 天天影视国产精品| 超色免费av| 免费日韩欧美在线观看| 久久久欧美国产精品| 国产精品秋霞免费鲁丝片| 国产精品久久久久成人av| 欧美人与善性xxx| 男女高潮啪啪啪动态图| 久久精品aⅴ一区二区三区四区| 十分钟在线观看高清视频www| 18禁动态无遮挡网站| 日韩av不卡免费在线播放| 综合色丁香网| 18禁国产床啪视频网站| 久久久国产一区二区| 在线观看一区二区三区激情| 日韩一卡2卡3卡4卡2021年| 十八禁高潮呻吟视频| 一区在线观看完整版| 悠悠久久av| 久久精品亚洲av国产电影网| 午夜激情av网站| 欧美日韩一区二区视频在线观看视频在线| 咕卡用的链子| 啦啦啦 在线观看视频| 免费久久久久久久精品成人欧美视频| 国产深夜福利视频在线观看| 男女下面插进去视频免费观看| 美女国产高潮福利片在线看| 夫妻性生交免费视频一级片| 女人爽到高潮嗷嗷叫在线视频| www.av在线官网国产| 久久99精品国语久久久| 老司机影院成人| 亚洲中文av在线| 好男人视频免费观看在线| 看免费成人av毛片| 精品国产国语对白av| 深夜精品福利| 青青草视频在线视频观看| 国产又色又爽无遮挡免| 国产高清国产精品国产三级| 另类亚洲欧美激情| 黑人欧美特级aaaaaa片| 亚洲成人国产一区在线观看 | 亚洲第一区二区三区不卡| 观看美女的网站| 五月开心婷婷网| 久久国产亚洲av麻豆专区| 九草在线视频观看| 国精品久久久久久国模美| 亚洲成色77777| netflix在线观看网站| 国产熟女欧美一区二区| av卡一久久| 你懂的网址亚洲精品在线观看| netflix在线观看网站| 最近中文字幕2019免费版| av卡一久久| 亚洲欧美一区二区三区黑人| 国产精品久久久久成人av| 永久免费av网站大全|