• <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 ?

    Weak-focused acoustic vortex generated by a focused ring array of planar transducers and its application in large-scale rotational object manipulation?

    2021-05-06 08:56:16YuzhiLi李禹志PeixiaLi李培霞NingDing丁寧GepuGuo郭各樸QingyuMa馬青玉JuanTu屠娟andDongZhang章東
    Chinese Physics B 2021年4期
    關(guān)鍵詞:丁寧

    Yuzhi Li(李禹志), Peixia Li(李培霞), Ning Ding(丁寧), Gepu Guo(郭各樸),Qingyu Ma(馬青玉),?, Juan Tu(屠娟), and Dong Zhang(章東)

    1School of Computer and Electronic Information/School of Artificial Intelligence,Nanjing Normal University,Nanjing 210023,China

    2Institute of Acoustics,Nanjing University,Nanjing 210093,China

    Keywords: acoustic vortex,weak-focused,large-scale object manipulation,acoustic scatter,acoustic radiation force

    1. Introduction

    Due to the orbital angular momentum transfer of helical wavefronts,the acoustic vortex(AV)[1–6]has been proved to possess the capability of object manipulation. The center pressure null[7,8]formed by the screw phase dislocation can be applied to form the potential well to trap small objects in a rotation manner. The AV beam can go deeply into tissues[9–11]to manipulate small targets[12–16]as vortex tweezers,exhibiting the application potential in the fields of particle manipulation and drug delivery in biomedical engineering. It was reported that the acoustic radiation torque(ART)[17]of a monochromatic nonparaxial AV beam was proportional to the power absorbed by the object with a factor of l/ω, where l was the topological charge of the AV.To generate an AV with a phase spiral, the phased technology for the point or quasipoint sources was often employed based on acoustic interference. AVs with l =1 and 2 were generated[18,19]using an 8-source array and the OAM transfer was verified by the measurement of the ART exerted on a hanging disk.For the phasecoded approach[20–22]applied to a ring array of N sources,the maximum topological charge of the AV was achieved and the circular distributions of pressure and phase were also discussed. However, the AVs generated by the ring array were along the center axis of the acoustic beam with a low-level trapping force, resulting in an instable axial manipulation of particles.

    A spherical transducer array was developed[23,24]to generate AVs and a stable trapping of particles of wavelength order was demonstrated. The rotation speed of particles was adjusted by regulating the amount of time for each direction of the emitted vortex. Whereas, for weak directional transducers with k0b=3.7 (product of the wave number k0and the transducer radius b), the axial width of the interference area could not be limited effectively by the main lobes. The axially controllable deep-level multiple traps[25]of AVs using directional sources (k0b=29.32) were investigated. The main-AV formed by main lobes was far away from the source plane in a divergent manner and the energy was not fully utilized to produce a strong capability of object manipulation. A triangular lattice phased array was reported[26]to generate a focused AV (FAV) with the peak pressure increased up to 3 times that of a non-focalized one. By mounting an acoustic lens on a phased array, a FAV was developed[27]to manipulate objects on a thin film. The clearest experiment concerning the ART on spheres[28]was observed by the simultaneous rotating and trapping of particles. Riaud et al.[11]reported that precursor swirling Rayleigh waves could degenerate into AVs after crossing a stack made of a liquid layer and its solid support, creating a localized acoustic trap in a fluid cavity. The inverse problem to design integrated transducers for arbitrary acoustic fields was solved and applied to design an integrated spiraling transducer for AVs. This technology was selective,label-free, biocompatible, flat, easy to miniaturize, and compatible with microfluidic disposable chips, which opened exciting prospects for cell printing and tissue engineering. In order to improve the selectivity and integrability of contactless particle manipulation,the potential of FAV[29]was unleashed by developing the first flat, compact, paired single electrode focalized acoustical tweezers,which relied on spiraling transducers obtained by folding a spherical AV on a flat piezoelectric substrate. The ability to grab and displace micrometric objects in a standard microfluidic environment with unique selectivity was demonstrated. However,due to the small size of the focal zone,the practical application of the FAV is still limited by the weak ART[30]exerted on objects and the possible acousto-thermal damage to biological tissues at the focal center.

    In this paper, by introducing the elevation angle to the planar transducers of an N-element ring array, the weakfocused acoustic vortex(WFAV)composed of a main-AV and N paraxial-AVs is constructed to conduct a large-scale rotational manipulation of objects in the focal plane. Compared with the ellipsoidal focal zone formed by the concave spherical transducers,the cone-shaped WFAV generated by the main lobes of the planar sources is much larger with the size inversely associated with the elevation angle. Based on acoustic scattering, the transverse properties and the capacity of rotational object trapping of the WFAV is analyzed in detail.Compare with the FAV, the higher ARF and ART exerted on an elastic ball can be produced by the WFAV in a larger radius.The pressure distribution of the WFAV is confirmed by the experimental scanning measurement in water and the capability of object manipulation in the focal plane is also verified by the rotational capture of particles on the water surface. The favorable results demonstrate the feasibility of large-scale rotational manipulation of objects with a strengthened ART and a reduced acousto-thermal damage to biological tissues. In addition,with a confocal design with a high intensity focused ultrasound(HIFU),the WFAV can be used to improve the therapeutic effect of HIFU therapy with the accumulation of drug particles,which might enable more potentials in clinical applications.

    2. Principle and Method

    The phase-coded approach[20]is employed to form the AV beam with a controllable topological charge l. The spatial angle and the initial phase of the n-th source are set to ?n=n(2π/N) and φn=nl(2π/N) for n=0 to N ?1. As shown in Fig.1(a), the acoustic pressure at (r,?,z) produced by the n-th source[25,31]can be calculated by

    where q0is the acoustic source strength, Rnand θnare the transmission distance and the radiation angle from the n-th source to(r,?,z). Thus,the acoustic pressure of the AV beam can be achieved as

    Therefore,the cone-shaped WFAV can be formed by the main lobes for θn<θ1N. Although many on-axis or off-axis sub-AVs can also be generated by the side lobes (θn>θ1N),they can be neglected in practical applications due to the lowlevel acoustic pressure.

    3. Numerical and experimental studies

    Numerical studies are conducted for an 8-source ring array with R=60 mm,b=7 mm,and θc=30?at f =1 MHz in water,the density and the acoustic speed in water are set to be ρ0=1000 kg/m3and c0=1500 m/s. Cross-sectional distributions of pressure and phase for the WFAV with l=1 at the focal distance(z=52.0 mm)are plotted in Figs.2(a1)and 2(a2).Concentric pressure circles with an obvious pressure zero at the center is clearly displayed in Fig.2(a1). The radii of the pressure peak and valley of the main-AV are about 0.85 mm and 1.8 mm, respectively. The main-AV in r < 1.8 mm is proved by the conspicuous clockwise phase spiral from ?π to π in Fig.2(a2), and an expanded AV is also identified by the phase spiral in r<3.7 mm. Meanwhile, eight phase spirals evenly distributed on the circumference(r=4.8 mm)demonstrate the occurrence of eight paraxial-AVs with the radius of 1.8 mm.Due to the interference of the main lobes of the planar transducers on the ring array, the number of paraxial-AVs is equal to that of the sources. In addition,obvious off-axis sub-AVs formed by side lobes can also be observed by the phase spirals in r >6.6 mm. Thus, the maximum radial distance of about 6.6 mm can be regarded as the radius of the WFAV,which is 4 times larger than the wavelength. The axial pressure profile in Fig.2(a3)shows a large-scale WFAV around the focal center. The main-AV and paraxial-AVs symmetrically distributed around the beam axis agree well with the crosssectional distributions in Figs.2(a1)and 2(a2). Whereas,several off-axis sub-AVs outside the WFAV are too low to be identified.

    The experimental ring array of eight planar transducers with the elevation angle of 30?was fabricated as displayed in Fig.1(b). The array bracket was manufactured by three-dimensional (3D) printing using the photopolymer material, and the planar transducers (radius 7 mm, center frequency 1 MHz)made of PZT were commercially customized by Chongqing Haifu Medical Technology Co. Ltd. An 8-channel phase-coded driving circuit[19,29]made by the direct digital synthesis(DDS)devices and the high-frequency power amplifiers was used to excite the transducers with the phase difference of π/4. The acoustic pressure was scanned by a needle hydrophone (Onda HNR-1000, Onda Corporation,USA) using two step motors (Newport M-ILS250, Newport Corporation,USA)at the step of 0.1 mm,and collected by the digital oscilloscope (Agilent DSO9064A, Agilent Technologies,USA).To reduce the influence of the near-field interference, the axial measurement distance was set from 20 mm to 80 mm. Besides,two magnets mounted inside and outside the water tank were used to conduct a contactless linear motion control of the ring array.

    The experimental cross-sectional distributions of pressure and phase in the focal plane at z=52.0 mm are illustrated in Figs. 2(b1) and 2(b2), which are in good agreements with the simulations in Figs.2(a1)and 2(a2). For the possible experimental errors in scanning measurements, the vortex center (indicated by the intersection of the axes) of the WFAV deviates slightly from the origin as shown in Fig.2(b1). As indicated by the arrows,a main-AV and eight paraxial-AVs located around are clearly displayed with obvious pressure circles,which are verified by the corresponding phase spirals as shown in Fig.2(b2).Meanwhile,several off-axis sub-AVs outside the WFAV can also be identified in Figs.2(a)and 2(b). In addition, the experimental axial profile in Fig.2(b3) in terms of the location and size of the main-AV and paraxial-AVs consists qualitatively with the simulation in Fig.2(a3).

    Also as indicated by the arrows in Fig.2(a1),normalized radial pressure distributions in the focal plane at ? =22.5?for the ring arrays of planar transducers with various elevation angles are plotted in Fig.3(a).Although there are several pressure valleys along the radial direction,the vortex centers of the main-AV and paraxial-AVs are located at the 1st and 4th pressure valleys of r=0 mm and 4.8 mm, and the radius of the WFAV is positioned at the 5-th pressure valley of r=6.6 mm.It shows that the radii of the main-AV and paraxial-AVs decrease accordingly for a larger elevation angle. As plotted in Fig.3(b), the radius in the focal plane and the axial width(?6 dB attenuation) of the WFAV exhibit a similar decreasing tendency with respect to the elevation angle. When the elevation angle is enhanced from 20?to 80?,the radius of the WFAV decreases from 9.8 mm to 3.4 mm with a declined axial width from 27.8 mm to 9.5 mm. For the array with θc=30?,the axial width(18.7 mm)and the radius(6.6 mm)are proved by the similar sizes as indicated in Fig.2(a3). Thus, the size of the WFAV can be controlled accurately by the elevation angle of the transducers,and a more concentrated WFAV with a smaller main-AV can be formed by a bigger elevation angle.

    To make a precise comparison with the WFAV,the model of the traditional FAV is developed by replacing each planar transducer with a concave spherical one with the conceptual diagram as shown in Fig.1(a). The focal length of the concave spherical transducers is set to R=60 mm with the height of the spherical cap of 0.4 mm to ensure the same surface area as the planar one. By applying the phase difference to the ring array,the FAV can be generated around the focus. Crosssectional distributions of pressure and phase in the focal plane of the FAV with l =1 are illustrated in Figs. 4(a) and 4(b),and the corresponding axial pressure profile is also presented in Fig.4(c). The FAV featured by the obvious concentric circles with a pressure null at the center is clearly displayed in Fig.4(a)and the formation of the FAV in r<1.8 mm is proved by the perfect phase spiral around the center in Fig.4(b). The circular pressure distributions of eight paraxial-AVs are incomplete with the pressure obviously lower than that of the FAV. In addition, the acoustic pressures of the off-axis sub-AVs are too low to be identified in Fig.4(a). Compared with the axial profile of the WFAV in Fig.2(a3), only the main-AV around the focus can be observed in Fig.4(c). Therefore,due to the focusing of the concave spherical transducers, the acoustic power is more concentrated in the FAV around the focal center.

    As plotted in Fig.4(d), the normalized radial pressure distribution of the WFAV at ? =22.5?in the focal plane is simulated to analyze the driving capability of the WFAV,and the corresponding distribution of the FAV is also provided for comparison. It shows that the pressure peak of the FAV is a little higher than that of the main-AV of the WFAV at r=0.9 mm,whereas,the pressure peak of the FAV decreases with the increase of the radius. When r>3.2 mm,the 3rd and the 4th acoustic pressure peak of the FAV is obviously lower than that of the WFAV,meaning that no obvious paraxial-AVs can be formed in the FAV. Then, the offset dependences of the tangential ARF and the corresponding ART exerted on the elastic ball (a = 0.5 mm) in the WFAV are compared with those of the FAV. The comparisons plotted in Fig.4(e) show that the tangential ARF of the FAV is stronger than that of the WFAV in the center region. When the ball is moved farther to dy>2.9 mm, a higher tangential ARF of the WFAV is produced, especially for the existence of paraxial-AVs at dy=5.6 mm. Meanwhile,the corresponding ART generated by the FAV is a little higher than that of the WFAV when the ball is located at the central region in dy<2.9 mm. With the further increase of dy,the ART of the WFAV enhances rapidly with the maximum value at dy=5.6 mm, which is about 9 times that of the FAV. Therefore, the improved capability of large-scale object manipulation can be created for the WFAV due to the higher ARF when 2.9 mm

    In order to further analyze the capability of object manipulation, the acoustic pressure scattered by the elastic ball with a=0.5 mm,ρs=980 kg/m3,and cs=2300 m/s is simulated. Supposing the elastic ball is located eccentrically at(0,0.8)mm in the focal plane at z=52.0 mm,cross-sectional pressure distributions scattered by the ball radiated from each transducer are illustrated in Figs.5(a)–5(h). Obvious pressure fluctuations indicate the acoustic diffraction and reflection of the elastic ball. By further considering the initial phases of the sources, distributions of pressure and phase of the WFAV are illustrated in Figs.5(i)and 5(j). The acoustic pressure on the left side of the ball is obviously higher than that on the right side as plotted in Fig.5(i), creating the ARF (about 8.2 nN,white arrows)along the normal direction of the helical wavefronts as shown in Fig.5(j). The ARF produced by the WFAV on the elastic ball deviates slightly from the tangent direction with a radial component towards the vortex center,which produces in an inward rotation driving for the ball. The direction of the inward object rotation is determined by the tangential and radial components of the ARF in the transverse plane.Thus,by considering the role of the arm,a strengthened ART can be produced by the WFAV,which is beneficial to the rotational manipulation of objects in a large scale.

    The performance of object manipulation of the WFAV is demonstrated by the experimental rotation and movement of the center accumulated polyethylene particles (a=0.5 mm).For the axial radiation force of nN level is too low to be measured, particles floating on the transparent surface of water were often used to study the characteristics of the rotational trapping in the focal plane at z=52 mm to improve the observation effect. Due to the action of the ARF, particles rotate anticlockwise around the center with an obvious accumulation in a circular distribution of the radius of 6.0 mm in Fig.6(a). For the WFAV is formed by the interference of the main lobes of the transducers, particles inside the WFAV can be easily driven by the strong ARF produced by the main-AV and the paraxial-AVs as shown in Fig.2. While,although the off-axis AVs can also be formed by the side lobes outside the WFAV, the acoustic power is too low to driven the particles. Therefore, as observed in the Supplementary video I, particles inside the central area with the radius of about 6.0 mm are gathered to the center in a rotation manner,while the ones outside keep a steady state. A clear circular demarcation(6.0 mm

    4. Discussion

    For the ring array of eight planar transducers with a given R0, the shape and size of the WFAV can be adjusted by the elevation angle θc, which is also limited by the configuration of the array and size of the transducers. For θc=90?, all the transducers are positioned in the source plane with the surfaces pointing to the center, and an octagon AV at the center inside the array can be formed by the main lobes of the sources.However, for this case, the object to be manipulated should be placed in the source plane without axial operation depth,which would limit the practical application of AV manipulations. While, for the specific angle of θc=0?, the model is the traditional ring array[25]with the transducer faces perpendicular to the beam axis, and the main-AV can be generated by the main lobes of the sources. However, due to the directivity of the transducers, the main-AV is far away from the source plane in a divergent manner, and the acoustic energy cannot be fully utilized to produce a strong capability of object manipulation.[38]Thus,the WFAV is proposed to shorten the axial distance of the focal zone with an improved capability of object manipulation.

    In order to obtain the accurate acoustic pressure for the WFAV,the laser vibrometer(Polytec OFV-503,Polytec Company, German) was used to measure the acoustic velocity on the planar transducer surface. By adjusting the experimental acoustic velocity on each transducers surface to 30 mm/s,the source pressure was about 45 kPa and the pressure peak of the WFAV reached 310 kPa by the acoustic focusing,producing an nN-level ARF in the focal plane. For the acoustic energy used in particle manipulations,the maximum pressure was less than MPa, and the nonlinear effect of the WFAV and the acoustothermal effect to biological tissues[39]were neglected. However, by further increasing the source pressure to achieve a pressure peak over MPa for the WFAV, the nonlinear effect should be considered to achieve a more accurate calculation of the ARF for object manipulations.

    As we know, the axial ARF along the center axis of an acoustic beam mainly works as the positive force to push particles away from the source plane. However,for an AV beam with a pressure null at the center,the negative force[40,42]exerted on a particle along the center axis is easy to generate at appropriate axial distances. The axial performance of a FAV[27]generated by a transducer array and a concave acoustic lens was studied by Baresch et al., and it was proved that the axial ARF was positive inside the beam focus and negative outside as the pushing and pulling forces.The particle reached an axial equilibrium position when the negative ARF balanced the positive one. In addition, Marzo et al.[24]demonstrated that the FAV was able to stably trap and effectively control the rotational speed of levitated samples by the independently tunable trapping forces and OAM.The radial and axial ARFs centered on the focus proved the existence of the ARF zero along the beam axis of the FAV. Thus, in order to improve the observation effect in water, objects floating on the water surface were often used to study the characteristics of rotational trapping in the focal plane without considering the axial ARF due to the force balance in the direction of gravity. By applying the holographic acoustic tweezers[43]of AVs using two 256-element phased arrays,the rotations of soap bubbles in opposite directions on the water surface were realized by Marzo and Drinkwater. Therefore, by considering the similar distributions of the WFAV and the FAV,the focal plane on the water surface with an axial radiation force balance in the direction of gravity can be treated as the optimized position to study the performance of the stable object trapping in the transverse plane.

    Although the experiments of particle rotation and movement provide the evidence for the WFAV,there are still some differences between the particle distributions and the theoretical expectations. Due to the electrostatic interaction, obvious particle aggregations are formed on the water surface.Only the rotation of the agglomerated particles as a whole is observed in the supplementary videos because the ARF of main-AV is much larger than of the paraxial-AVs. Meanwhile,independent rotations of several particles can also identified around the centers of the paraxial-AVs. Meanwhile, compared with the WFAV, the acoustic pressure of the off-axis sub-AVs is much smaller and the ARF is too low to produce particle rotation. The clear circular demarcation without particles between the paraxial-AVs and the off-axis sub-AVs in 6.0 mm< r < 8.0 mm is produced by the inward trapping force inside the WFAV and the outward gradient force outside along the radial direction. In addition, the high-intensity focused ultrasound(HIFU)[39]can be used to treat tumors using the thermal ablation of the focused ultrasound energy without the synergy of drug particles. Thus,with a confocal design as shown in Fig.7,the ring array with the hollow structure can be equipped around a HIFU transducer to form a WFAV covering the elliptical focal zone of thermal ablation. Combined with the effect of large-scale particle trapping, the WFAV can be applied to improve the therapeutic effect of tumor treatments during HIFU therapy with the accumulation of drug particles,which might enable more potentials in medical applications.

    As the conventional AV,objects with the size smaller than the radius of the WFAV can be captured stably, which is determined by the structure of the ring array and the topological charge. For the configuration of the system in this study,the radius(6.6 mm)of the WFAV with l=1 is 4 times larger than the wavelength. Therefore, objects of nm, μm, and mm scales can be manipulated stably by the WFAV, showing a great potential in multi-scale object trapping, especially for bio-particles or drug particles in biomedical applications. As presented in the principle section,the scattered acoustic pressure and the corresponding ARF of the elastic ball are also impacted by βlin Eq.(4),which is determined by the impedance difference between the elastic ball and surrounding water. The particles with a negative acoustic contrast factor[44,45],e.g.,the polydimethylsiloxane(PDMS)microparticles,[46]can migrate transversely with the pressure gradient towards the area of a high pressure, and they are hardly to be accumulated to the center by the WFAV.Therefore,only the regular particles with a positive acoustic contrast factor can be manipulated by the WFAV.

    5. Conclusion

    By introducing the elevation angle to the planar transducers of an N-element ring array, the WFAV is constructed to conduct a controllable rotational object manipulation in a large scale. Compared with the traditional FAV produced by concave spherical transducers,a much larger scope of the WFAV composed of a main-AV and N paraxial-AVs can be generated with the size inversely associated with the elevation angle. The inward object rotation is demonstrated by the ARF and the ART exerted on an elastic ball based on acoustic scattering. The WFAV generated by an 8-source ring array is verified by the scanning measurement of the acoustic field,and the capability of object manipulation is proved by the rotational trapping of floating particles on the water surface in the focal plane. The favorable results demonstrate that the WFAV is applicable in a large-scale object manipulation with a strengthened ART,exhibiting promising perspectives in medical applications.

    猜你喜歡
    丁寧
    Crown evolution kinematics of a camellia oil droplet impacting on a liquid layer
    丁寧在關(guān)鍵單打比賽中的技戰(zhàn)術(shù)分析
    丁寧冠軍的心
    人物(2018年1期)2018-04-26 09:24:24
    天津全運(yùn)會(huì)乒乓球比賽中丁寧的技戰(zhàn)術(shù)分析
    丁寧你憑什么
    賽馬
    《丁寧在中美乒乓球交流賽》
    海峽影藝(2013年3期)2013-12-04 03:22:32
    對丁寧在2013巴黎世乒賽半決賽的技戰(zhàn)術(shù)分析
    有友誼,才會(huì)有勝利
    知識(shí)窗(2011年8期)2011-05-14 09:07:55
    一二三四社区在线视频社区8| 男人舔女人的私密视频| 丁香欧美五月| 国产伦人伦偷精品视频| 在线观看日韩欧美| 国产激情久久老熟女| av电影中文网址| 久久久久久人人人人人| 十八禁网站免费在线| 最近最新免费中文字幕在线| 最新在线观看一区二区三区| 色播在线永久视频| 波多野结衣高清无吗| 国产精品一区二区三区四区久久 | 91大片在线观看| 亚洲最大成人中文| 亚洲全国av大片| 亚洲精品色激情综合| 久久精品91无色码中文字幕| 久久久久国产一级毛片高清牌| 成人欧美大片| 少妇粗大呻吟视频| 欧美激情极品国产一区二区三区| 后天国语完整版免费观看| www.熟女人妻精品国产| 免费无遮挡裸体视频| 午夜影院日韩av| 日韩三级视频一区二区三区| 久9热在线精品视频| 国产久久久一区二区三区| 亚洲自偷自拍图片 自拍| 亚洲全国av大片| 99热只有精品国产| 亚洲精品久久国产高清桃花| 久久午夜综合久久蜜桃| 国产一区二区三区视频了| 亚洲激情在线av| 欧美成人性av电影在线观看| 久久久国产成人精品二区| 亚洲av成人一区二区三| 日韩欧美 国产精品| 一进一出好大好爽视频| 18美女黄网站色大片免费观看| 国产成人欧美在线观看| 久久久久国产精品人妻aⅴ院| 午夜影院日韩av| 天天添夜夜摸| av片东京热男人的天堂| 中文字幕精品免费在线观看视频| 亚洲第一av免费看| 成人午夜高清在线视频 | 91麻豆精品激情在线观看国产| 老鸭窝网址在线观看| 精品无人区乱码1区二区| 中出人妻视频一区二区| 亚洲国产精品合色在线| av欧美777| 狠狠狠狠99中文字幕| 亚洲一区高清亚洲精品| 欧美精品啪啪一区二区三区| 亚洲国产毛片av蜜桃av| 狠狠狠狠99中文字幕| 精品午夜福利视频在线观看一区| 熟妇人妻久久中文字幕3abv| 亚洲欧美日韩无卡精品| 欧美zozozo另类| 女人被狂操c到高潮| av电影中文网址| 亚洲自拍偷在线| 黄色视频,在线免费观看| 国产麻豆成人av免费视频| 一级毛片精品| 午夜影院日韩av| 免费观看人在逋| 国产区一区二久久| 欧美黑人巨大hd| 精品一区二区三区四区五区乱码| 中文字幕高清在线视频| 麻豆久久精品国产亚洲av| 国产91精品成人一区二区三区| 免费看十八禁软件| 丰满人妻熟妇乱又伦精品不卡| 亚洲色图av天堂| 久久精品夜夜夜夜夜久久蜜豆 | 给我免费播放毛片高清在线观看| 窝窝影院91人妻| 午夜福利高清视频| 黑丝袜美女国产一区| 中文字幕精品亚洲无线码一区 | 日韩欧美三级三区| 国产成人av教育| 成人精品一区二区免费| www.自偷自拍.com| 精品免费久久久久久久清纯| 99热这里只有精品一区 | 中出人妻视频一区二区| 女同久久另类99精品国产91| 桃红色精品国产亚洲av| 一本精品99久久精品77| 国产高清视频在线播放一区| 国产午夜精品久久久久久| 亚洲性夜色夜夜综合| 国产麻豆成人av免费视频| 亚洲午夜理论影院| 精品人妻1区二区| 亚洲性夜色夜夜综合| 欧美中文日本在线观看视频| 国产视频一区二区在线看| 国产91精品成人一区二区三区| 夜夜爽天天搞| 老司机午夜福利在线观看视频| 亚洲自偷自拍图片 自拍| 一a级毛片在线观看| cao死你这个sao货| 人人澡人人妻人| 欧美日韩黄片免| 黄色视频不卡| 午夜老司机福利片| 91九色精品人成在线观看| 日韩成人在线观看一区二区三区| 丝袜美腿诱惑在线| 欧美另类亚洲清纯唯美| 亚洲精品在线美女| 日韩视频一区二区在线观看| 国产av一区在线观看免费| 久久香蕉精品热| 免费高清视频大片| 99热6这里只有精品| 精品卡一卡二卡四卡免费| 亚洲欧美日韩无卡精品| 亚洲精华国产精华精| 欧美大码av| 动漫黄色视频在线观看| 亚洲性夜色夜夜综合| 中出人妻视频一区二区| 又紧又爽又黄一区二区| 欧美日韩中文字幕国产精品一区二区三区| 亚洲欧美激情综合另类| av免费在线观看网站| 免费电影在线观看免费观看| 中文字幕精品亚洲无线码一区 | 国产av不卡久久| 热99re8久久精品国产| 搡老熟女国产l中国老女人| 一级a爱片免费观看的视频| 亚洲一码二码三码区别大吗| 一本精品99久久精品77| 亚洲真实伦在线观看| 性色av乱码一区二区三区2| 亚洲男人的天堂狠狠| 国产亚洲av高清不卡| 亚洲熟妇熟女久久| 欧美一级毛片孕妇| 国产亚洲av高清不卡| 国产av不卡久久| 国产97色在线日韩免费| 欧美成人午夜精品| 黑丝袜美女国产一区| 美女扒开内裤让男人捅视频| 久久精品91蜜桃| 国产午夜精品久久久久久| 性欧美人与动物交配| 国产黄片美女视频| 黄片小视频在线播放| 香蕉国产在线看| 久久香蕉激情| 天堂影院成人在线观看| 成人av一区二区三区在线看| 满18在线观看网站| 制服人妻中文乱码| 韩国精品一区二区三区| 性色av乱码一区二区三区2| 级片在线观看| 久久久久久人人人人人| 满18在线观看网站| 真人做人爱边吃奶动态| 久久婷婷人人爽人人干人人爱| 欧美人与性动交α欧美精品济南到| 日日爽夜夜爽网站| 美女大奶头视频| 18美女黄网站色大片免费观看| 成人一区二区视频在线观看| 人人妻人人澡欧美一区二区| 免费看十八禁软件| 在线观看舔阴道视频| 久久亚洲精品不卡| 99久久精品国产亚洲精品| 激情在线观看视频在线高清| 久久久久久国产a免费观看| 少妇的丰满在线观看| 一级黄色大片毛片| 国产精品自产拍在线观看55亚洲| 久久午夜综合久久蜜桃| 午夜免费成人在线视频| 一本久久中文字幕| 日本熟妇午夜| АⅤ资源中文在线天堂| 午夜福利成人在线免费观看| 精品电影一区二区在线| 亚洲五月天丁香| 91国产中文字幕| 精品第一国产精品| 成人三级黄色视频| www.www免费av| 一级毛片精品| 国产精品久久久av美女十八| tocl精华| 白带黄色成豆腐渣| 欧美日韩中文字幕国产精品一区二区三区| 亚洲欧洲精品一区二区精品久久久| 一进一出抽搐gif免费好疼| 精品国产乱码久久久久久男人| 中文在线观看免费www的网站 | 久久精品国产亚洲av香蕉五月| 欧美成狂野欧美在线观看| 国产亚洲精品av在线| 欧美午夜高清在线| 国产成人欧美在线观看| 成人国产一区最新在线观看| 高清毛片免费观看视频网站| 亚洲最大成人中文| 久久久精品欧美日韩精品| 中文字幕最新亚洲高清| 丁香欧美五月| 1024手机看黄色片| 国产伦一二天堂av在线观看| 亚洲精品美女久久久久99蜜臀| 欧美丝袜亚洲另类 | 欧美一级a爱片免费观看看 | 色播亚洲综合网| 亚洲精品国产一区二区精华液| 国语自产精品视频在线第100页| 国产精品一区二区三区四区久久 | 亚洲一区二区三区色噜噜| 亚洲av日韩精品久久久久久密| 欧美另类亚洲清纯唯美| 欧美又色又爽又黄视频| 久久九九热精品免费| 国产精品亚洲美女久久久| 国产精品免费一区二区三区在线| 欧美日韩亚洲国产一区二区在线观看| 99久久久亚洲精品蜜臀av| 亚洲七黄色美女视频| 亚洲精品av麻豆狂野| 国产不卡一卡二| 亚洲人成电影免费在线| 久久香蕉精品热| 黄频高清免费视频| 亚洲av片天天在线观看| 欧美激情极品国产一区二区三区| 国产精品一区二区免费欧美| 男女下面进入的视频免费午夜 | 午夜两性在线视频| 日日干狠狠操夜夜爽| 免费在线观看日本一区| 免费av毛片视频| 日韩一卡2卡3卡4卡2021年| 国产午夜福利久久久久久| 欧美成人性av电影在线观看| 国产伦一二天堂av在线观看| 亚洲无线在线观看| 亚洲在线自拍视频| 日韩欧美一区二区三区在线观看| 成熟少妇高潮喷水视频| 亚洲精品一区av在线观看| 在线观看免费日韩欧美大片| 午夜激情av网站| 露出奶头的视频| 国产精品 欧美亚洲| 久久久久亚洲av毛片大全| 在线观看免费日韩欧美大片| 亚洲五月色婷婷综合| 久久中文字幕人妻熟女| 亚洲国产欧美网| 免费在线观看完整版高清| 中出人妻视频一区二区| 嫩草影视91久久| 中亚洲国语对白在线视频| 亚洲av五月六月丁香网| svipshipincom国产片| 99精品久久久久人妻精品| 成人一区二区视频在线观看| 久久久久久人人人人人| 国产精品免费一区二区三区在线| 欧美日韩福利视频一区二区| 欧美性长视频在线观看| 19禁男女啪啪无遮挡网站| 亚洲精品国产一区二区精华液| 久久久久久免费高清国产稀缺| 国产成人精品无人区| 黑人欧美特级aaaaaa片| 两个人免费观看高清视频| 国产日本99.免费观看| 变态另类成人亚洲欧美熟女| 国产精品九九99| 久久精品国产99精品国产亚洲性色| 亚洲精品国产区一区二| 俺也久久电影网| 在线永久观看黄色视频| 老熟妇仑乱视频hdxx| 禁无遮挡网站| 成人特级黄色片久久久久久久| 免费在线观看黄色视频的| 色精品久久人妻99蜜桃| 香蕉丝袜av| 亚洲美女黄片视频| 欧美在线黄色| 香蕉av资源在线| 日韩欧美三级三区| 日韩欧美免费精品| 无人区码免费观看不卡| 国产片内射在线| 可以在线观看毛片的网站| 欧美最黄视频在线播放免费| 女人爽到高潮嗷嗷叫在线视频| 亚洲一区二区三区不卡视频| 成人特级黄色片久久久久久久| 亚洲第一av免费看| 波多野结衣高清作品| 精品国产乱码久久久久久男人| 国产av又大| 欧美中文综合在线视频| 久久人妻av系列| 精品国内亚洲2022精品成人| 777久久人妻少妇嫩草av网站| 此物有八面人人有两片| 88av欧美| 日本免费a在线| 麻豆国产av国片精品| xxxwww97欧美| 高潮久久久久久久久久久不卡| 亚洲自偷自拍图片 自拍| 夜夜看夜夜爽夜夜摸| 美女免费视频网站| 丝袜美腿诱惑在线| 午夜老司机福利片| 国产人伦9x9x在线观看| 欧美激情久久久久久爽电影| 亚洲 国产 在线| 婷婷六月久久综合丁香| 亚洲九九香蕉| 国产成人一区二区三区免费视频网站| 一本精品99久久精品77| 9191精品国产免费久久| 日韩中文字幕欧美一区二区| 午夜影院日韩av| 亚洲熟妇熟女久久| 又大又爽又粗| 亚洲黑人精品在线| 亚洲第一电影网av| 欧美绝顶高潮抽搐喷水| 欧美一区二区精品小视频在线| 国产精品久久久人人做人人爽| 久久精品国产亚洲av高清一级| 国产亚洲欧美98| 无限看片的www在线观看| 日韩精品青青久久久久久| 在线免费观看的www视频| 国产成人精品久久二区二区91| 禁无遮挡网站| 国产精品永久免费网站| 好看av亚洲va欧美ⅴa在| 亚洲一区二区三区色噜噜| 欧美激情极品国产一区二区三区| 操出白浆在线播放| 久久久久久久久免费视频了| 成人特级黄色片久久久久久久| 香蕉av资源在线| 1024视频免费在线观看| 日本在线视频免费播放| 看黄色毛片网站| 自线自在国产av| 18禁国产床啪视频网站| 亚洲欧美一区二区三区黑人| 可以免费在线观看a视频的电影网站| 国产亚洲精品综合一区在线观看 | 亚洲avbb在线观看| 久久青草综合色| 99国产极品粉嫩在线观看| 女生性感内裤真人,穿戴方法视频| 在线观看免费日韩欧美大片| 一级毛片女人18水好多| 久久精品91蜜桃| 国内揄拍国产精品人妻在线 | 99国产精品一区二区蜜桃av| 日韩一卡2卡3卡4卡2021年| 国产亚洲精品av在线| 色在线成人网| 1024视频免费在线观看| 国产熟女xx| 国产又色又爽无遮挡免费看| 一边摸一边抽搐一进一小说| 日日摸夜夜添夜夜添小说| 男人舔女人的私密视频| 成人亚洲精品一区在线观看| 女警被强在线播放| 亚洲va日本ⅴa欧美va伊人久久| 国产高清激情床上av| 久久久久九九精品影院| 黄色a级毛片大全视频| 国产男靠女视频免费网站| 搡老妇女老女人老熟妇| 成人亚洲精品av一区二区| 欧美日韩瑟瑟在线播放| 一区二区日韩欧美中文字幕| 欧美成狂野欧美在线观看| 无限看片的www在线观看| 欧美午夜高清在线| 成年人黄色毛片网站| 欧美绝顶高潮抽搐喷水| 久久精品影院6| 色综合欧美亚洲国产小说| 午夜两性在线视频| or卡值多少钱| 亚洲avbb在线观看| 一进一出抽搐gif免费好疼| 国内毛片毛片毛片毛片毛片| 精品久久蜜臀av无| 精品不卡国产一区二区三区| 欧美日韩中文字幕国产精品一区二区三区| 特大巨黑吊av在线直播 | 免费在线观看完整版高清| 久久久国产成人免费| 少妇熟女aⅴ在线视频| 亚洲 国产 在线| 国产午夜精品久久久久久| 国产激情久久老熟女| 一进一出抽搐gif免费好疼| 18禁美女被吸乳视频| 国内精品久久久久精免费| 精品国产一区二区三区四区第35| 免费女性裸体啪啪无遮挡网站| 亚洲欧洲精品一区二区精品久久久| 国产男靠女视频免费网站| 久9热在线精品视频| 亚洲欧美精品综合一区二区三区| 亚洲国产欧洲综合997久久, | 色婷婷久久久亚洲欧美| 日韩 欧美 亚洲 中文字幕| 久久天躁狠狠躁夜夜2o2o| 50天的宝宝边吃奶边哭怎么回事| 男女下面进入的视频免费午夜 | 美女午夜性视频免费| 免费看美女性在线毛片视频| 亚洲免费av在线视频| 一级毛片精品| 亚洲全国av大片| 国产精品九九99| 老司机午夜十八禁免费视频| 侵犯人妻中文字幕一二三四区| 99在线人妻在线中文字幕| 狂野欧美激情性xxxx| 国产99白浆流出| 国产三级黄色录像| 成人国语在线视频| 少妇熟女aⅴ在线视频| 国产高清激情床上av| 成人手机av| 一级毛片精品| 亚洲精品久久成人aⅴ小说| 亚洲一卡2卡3卡4卡5卡精品中文| 精品卡一卡二卡四卡免费| 男人舔女人下体高潮全视频| 日韩高清综合在线| 99精品在免费线老司机午夜| 丁香欧美五月| 麻豆成人午夜福利视频| 黑人操中国人逼视频| 国产蜜桃级精品一区二区三区| tocl精华| 91九色精品人成在线观看| 久久国产精品男人的天堂亚洲| 中国美女看黄片| 一区二区三区国产精品乱码| 久久久国产欧美日韩av| 黄频高清免费视频| 久久国产精品人妻蜜桃| 好男人电影高清在线观看| 最近最新中文字幕大全免费视频| 级片在线观看| 亚洲专区中文字幕在线| 极品教师在线免费播放| www.熟女人妻精品国产| 男人舔奶头视频| 69av精品久久久久久| 黄色丝袜av网址大全| 欧美+亚洲+日韩+国产| 一个人观看的视频www高清免费观看 | 日韩 欧美 亚洲 中文字幕| 一本一本综合久久| netflix在线观看网站| 一区福利在线观看| 制服诱惑二区| 777久久人妻少妇嫩草av网站| 91成年电影在线观看| 中文在线观看免费www的网站 | 久久久久免费精品人妻一区二区 | 听说在线观看完整版免费高清| svipshipincom国产片| 日韩欧美国产一区二区入口| 禁无遮挡网站| 女性被躁到高潮视频| 视频区欧美日本亚洲| 国产在线精品亚洲第一网站| 午夜影院日韩av| 国产欧美日韩一区二区精品| 婷婷亚洲欧美| 成在线人永久免费视频| 久久人妻av系列| 一区福利在线观看| 国产单亲对白刺激| 18禁观看日本| 日本免费a在线| 热re99久久国产66热| 久久亚洲精品不卡| 午夜激情福利司机影院| 不卡一级毛片| 18禁裸乳无遮挡免费网站照片 | 动漫黄色视频在线观看| 国产精品久久久久久人妻精品电影| 国产精品亚洲美女久久久| 国产精品免费一区二区三区在线| 国产激情久久老熟女| 在线视频色国产色| 精品一区二区三区四区五区乱码| 亚洲精品中文字幕在线视频| 色精品久久人妻99蜜桃| av电影中文网址| 长腿黑丝高跟| 国内久久婷婷六月综合欲色啪| 91成人精品电影| 免费在线观看黄色视频的| 妹子高潮喷水视频| 18禁裸乳无遮挡免费网站照片 | 美女国产高潮福利片在线看| 久久精品影院6| 制服人妻中文乱码| 日韩精品免费视频一区二区三区| 久99久视频精品免费| 国产精品一区二区精品视频观看| 亚洲av电影在线进入| 午夜久久久在线观看| 神马国产精品三级电影在线观看 | 亚洲av电影在线进入| 亚洲av片天天在线观看| 天堂动漫精品| 伦理电影免费视频| 亚洲第一青青草原| 欧美中文综合在线视频| 18禁黄网站禁片免费观看直播| 在线观看免费午夜福利视频| 欧美最黄视频在线播放免费| 亚洲男人天堂网一区| 色尼玛亚洲综合影院| 欧美黑人精品巨大| 99热这里只有精品一区 | 视频在线观看一区二区三区| av免费在线观看网站| 日韩av在线大香蕉| 久热爱精品视频在线9| 99久久无色码亚洲精品果冻| 超碰成人久久| 视频区欧美日本亚洲| 91在线观看av| av在线天堂中文字幕| 好看av亚洲va欧美ⅴa在| 51午夜福利影视在线观看| 成人精品一区二区免费| 99在线人妻在线中文字幕| xxx96com| 日韩精品免费视频一区二区三区| 亚洲免费av在线视频| av天堂在线播放| 中文字幕精品亚洲无线码一区 | 巨乳人妻的诱惑在线观看| 亚洲人成伊人成综合网2020| 色老头精品视频在线观看| 精品国产乱码久久久久久男人| 精品高清国产在线一区| 90打野战视频偷拍视频| 淫妇啪啪啪对白视频| 免费电影在线观看免费观看| 高清在线国产一区| 日韩 欧美 亚洲 中文字幕| 久久久国产成人精品二区| 婷婷精品国产亚洲av在线| 亚洲成人久久爱视频| 国产一区二区三区视频了| 午夜精品在线福利| 成人特级黄色片久久久久久久| 18美女黄网站色大片免费观看| 国产精品一区二区精品视频观看| 老鸭窝网址在线观看| 国产精品99久久99久久久不卡| 大型av网站在线播放| 婷婷亚洲欧美| 满18在线观看网站| 久久久久国产精品人妻aⅴ院| 免费女性裸体啪啪无遮挡网站| 国产成+人综合+亚洲专区| 一个人免费在线观看的高清视频| 亚洲av中文字字幕乱码综合 | 国产成人一区二区三区免费视频网站| 日本免费一区二区三区高清不卡| 久久性视频一级片| 国产精品综合久久久久久久免费| 久9热在线精品视频| 免费在线观看影片大全网站| 好男人在线观看高清免费视频 | 色精品久久人妻99蜜桃| 国产精品免费视频内射| 久久久久九九精品影院| 久久精品91蜜桃| 真人一进一出gif抽搐免费| 国产99白浆流出|