• <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 ?

    Synaptic plasticity and classical conditioning mimicked in single indium-tungsten-oxide based neuromorphic transistor*

    2021-05-24 02:23:36RuiLiu劉銳YongliHe何勇禮ShanshanJiang姜珊珊LiZhu朱力ChunshengChen陳春生YingZhu祝影andQingWan萬青
    Chinese Physics B 2021年5期
    關(guān)鍵詞:劉銳

    Rui Liu(劉銳), Yongli He(何勇禮), Shanshan Jiang(姜珊珊), Li Zhu(朱力),Chunsheng Chen(陳春生), Ying Zhu(祝影), and Qing Wan(萬青)

    School of Electronic Science and Engineering,Nanjing University,Nanjing 210023,China

    Keywords: neuromorphic transistors,synaptic plasticity,oxide-based semiconductors,classical conditioning

    1. Introduction

    Human brain can process multi-dimensional information simultaneously because it is a parallel, plastic, and faulttolerant neural network with ~1011neurons and ~1015synapses.[1,2]Although advanced supercomputers based on silicon based CMOS integrated circuit can perform precise digital calculation very fast,the energy consumption and space occupation are enormous.[3,4]In order to deal with complicated and unstructured data efficiently, the concept of brainlike computing and neuromorphic system was proposed.[5]

    In neuroscience, learning and memory are established on the change of synaptic weight between neurons.[6]According to various time scales, synaptic plasticity could be classified as short-term plasticity (STP) and long-term plasticity (LTP). STP is temporary change of synaptic weight which persists a few milliseconds or minutes. However,LTP will last for a few hours, or longer.[7]By enhancing or shortening synaptic strength, synaptic plasticity could be modified or transformed.[8–16]During the past decade, twoterminal devices, such as memristor, have been proposed to emulate biological synapses.[17–21]In addition,multi-terminal transistors have been also proposed for artificial synapse application.[22–32]With additional control gate electrodes providing pre-synaptic signal inputs,post-synaptic current can be read synchronously. By now, some synaptic functions, such as excitatory post-synaptic current(EPSC),paired-pulse facilitation (PPF), metaplasticity, spike timing dependent plasticity (STDP), have been successfully simulated. With a huge gate capacitance, electric-double-layer (EDL) transistors can operate at a very low voltage. Furthermore,electrostatic modulation and electrochemical process in electrolyte gated EDL transistors are very similar to the ionic modulation in biological synapses. Thus, these transistors have great value in neuromorphic systems.[9,10,28–30]

    Associative learning plays an indispensable role in individual adaptability, and classical conditioning is a simple example.[33]A few reports been demonstrated the emulation of this behavior in new-concept electronic devices.[34–38]Although the classical conditioning could be successfully emulated by these devices, a complex circuit was usually employed in the experiment. Recently, a dual-gated synaptic transistor was used to mimic classical conditioning. Inputs applied on the topgate and bottomgate were regarded as the conditioned stimulus (CS) and unconditioned stimulus (US),respectively.[39]According to STDP learning rules, Zhu et al.[40]illustrated classical conditioning in an oxide-based neuromorphic transistor. US and CS were applied on drain electrode and gate, respectively. Especially, Yang et al.[41]and Chen et al.[42]took the advantage of different voltages on behalf of CS and US to investigate the classical conditioning on a memristor and a transistor,respectively.

    Here,we fabricated indium-tungsten-oxide(IWO)-based neuromorphic transistors gated by proton conducting chitosan films. Some synaptic functions, such as EPSC, PPF, filtering, were emulated. Moreover, two types of STDP (Hebbian STDP, and anti-Hebbian STDP) and multistore memory(sensory memory, short-term memory, and long-term memory) were also emulated. At last, classical conditioning was successfully demonstrated. Such neuromorphic devices have potential application in neuromorphic systems.

    2. Experimental details

    Firstly,acetic acid(~2 wt%)is added into deionized water. Secondly, chitosan solution (~2 wt%) is prepared by dissolving chitosan powder into above solvent. Thirdly, chitosan solution is drop-coated onto the ITO glass substrates and put in ambient air to shape into homogeneous chitosan films. Next, patterned IWO films (980 μm × 1600 μm) are deposited on the chitosan films with a metal shadow mask by sputtering with a RF power of 100 W, an Ar flow rate of 28 sccm, and a working pressure of 0.5 Pa. The target material is IWO (In2O3: WO3= 99 : 1 in wt.%). Finally, patterned Ag drain/source electrodes are evaporated on the IWO films by vacuum thermal evaporation. The channel width(W)and length (L) are 1000 mm and 80 mm, respectively. The schematic diagram of the IWO-based neuromorphic transistor is shown in Fig. 1(a). The frequency dependent capacitance of the chitosan electrolyte film is characterized using the impedance analyzer(HIOKI IM 3533-01 LCR meter).Electrical performance of the IWO-based synaptic transistors is measured by source measurement units(Keithley 2636B).

    3. Results and discussion

    The specific capacitance curve of the chitosan film is shown in Fig.S1(a). An EDL capacitor can be formed due to the accumulation of proton at chitosan/metal electrode under an external field. A maximal specific gate capacitance value(Ci)of ~5.7μF/cm2can be measured at 1.0 Hz. Output plots and transfer characteristics are provided in Figs. S1(b) and S1(c), respectively. From these output plots, the devices exhibit a good ohmic contact at low Vds. Because of the mobile protons in the chitosan electrolyte, a counterclockwise hysteresis can be observed in the transfer curve, which is necessary for synaptic function emulation. The current on/off ratio of the IWO-based synaptic transistor is estimated to be~2.0×106. Moreover,as shown in Fig.S1(d),the gate leakage current is measured to be as low as 2.0 nA. Here, the modulation of the IWO channel conductance should be explained. Under a positive gate voltage,proton in the chitosan film will migrate to the channel/chitosan interface. Such interfacial EDL modulation can modulate the IWO channel current at a low gate voltage range. Thanks to the mobile proton and interfacial EDL modulation,biological synaptic functions can be emulated in an IWO-based synaptic transistor. Here we should point that the properties of the oxide-based EDL transistors can be influenced by the humility,so in the future,device package should be done in order to control the humidity.Temperature can also influence the electrical properties of the oxide-based EDL transistors gated by electrolyte,our preliminary experimental results show that such device can operate safely in the temperature range of 0°C to 80°C. In fact, as a biological neural network system, our brain only works in a very narrow temperature range. So,function is the first and the temperature range is secondary. In the future, controlling the temperature for a small volume brain-like system should not be a big problem.

    Fig.1. (a)A diagram of the IWO-based neuromorphic transistor. (b)A diagram showing the biological synapse structure.

    As shown in Fig.1(b),a synapse consists of pre-synapse,cleft,and post-synapse,and biological signal can be transmitted from the pre-synapse to the post-synapse. Some investigations indicated that the synaptic plasticity could be tuned by neurotransmitters or ionic fluxes in the cleft while the action potential is triggered by the pre-synapse.[6,7,43]The operation principle of the IWO-based neuromorphic transistor is similar to the process of synaptic plasticity modulation. When a pre-synaptic spike is evoked, an EPSC in IWO channel will be measured with a small reading voltage applied between the source and drain electrode(Vds).

    Figure 2(a)shows a classical EPSC response of our IWObased neuromorphic transistor. The pre-synaptic spike is(0.2 V, 20 ms) and the reading voltage (Vds) is 0.1 V. When the spike comes to the end, a max EPSC value of ~4.7 nA is measured. The EPSC curve increases quickly in response to the pre-synaptic spike and then decays to the initial level step by step. The movement of proton within chitosan film plays a significant role in triggering EPSC. When a positive pulse voltage is applied on the gate electrode, proton will accumulate at electrolyte/IWO interface. After the pre-synaptic spike, proton will migrate to the balanced position, and the current returns to the initial level.[10]The energy dissipation of a spike event can be calculated by W =Ipeak×t×Vds, where Ipeakand t are the peak value and pulse width, respectively.The energy consumption per spike is estimated to be ~9.4 pJ.Figure 2(b)shows the energy consumption with various pulse amplitudes. As Vgsreduces, the energy consumption will reduce. Moreover, the energy consumption is also influenced by reading voltage Vdsand spike duration. When the reading voltage is reduced to 0.01 V,the energy consumption can be reduced to ~0.5 pJ,and the corresponding EPSC curve is shown in Fig.S2. Such energy consumption is much less than that of the classical CMOS-based artificial synapse.[44]

    Fig. 2. (a) A post-synaptic current of the IWO-based synaptic transistor measured under a voltage spike (0.2 V, 20 ms). (b) Energy consumption changes with Vgs. (c) PPF index as a function of ΔT. (d) Spike frequency dependent EPSC gain.

    As an important short-term plasticity, PPF is induced by 2 serial pulses with a short time interval (ΔT). Due to the successive release of neurotransmitters, the second spike response will be enhanced. PPF is widely considered to play a crucial role in temporal signal decoding.[7]In this work,PPF can be emulated in single IWO-based synaptic transistor.The inset in Fig. 2(c) is a response curve of PPF. The EPSC curves are evoked by two pre-synaptic spikes(0.2 V,20 ms)at ΔT =20 ms. As shown by the curve,the second EPSC peak is larger than the first one.As we all know,the movement of proton in chitosan takes some relaxation time. Considering ΔT is less than the relaxation time, some protons will not migrate back to their initial position. As a result, more protons will gather at the interface and the post-synaptic current in the IWO channel layer will also increase due to the corresponding field effect modulation. Figure 2(c)shows the PPF as a function of the interval time between two input spikes. A maximum PPF index of ~126 % is measured at ΔT =20 ms, and the PPF index decreases gradually when ΔT increases gradually.

    Thanks to short-term synaptic facilitation, synapse can exhibit a high-pass filtering behavior. Such filtering is a primary operation which allows post-synaptic neurons to behaviorally perceive the relevant stimulus characteristics from presynaptic spike trains.[29,45]Based on the PPF features of the proposed IWO-based neuromorphic transistor,stronger synaptic responses can be observed when the high frequency presynaptic stimulus is applied on the gate electrode. Figure 2(d)shows the frequency dependent EPSC gain. Each spike train contains eight spikes (0.2 V, 20 ms). When the spike frequency increases, the EPSC gain (A8/A1) increases accordingly. Thus,a biological filtering is successfully emulated.

    Fig.3. (a)Six pair of pre-synaptic and post-synaptic spikes adopted in Hebbian STDP test. (b)Measurements for anti-Hebbian STDP learning rule.

    In neuroscience,long-term plasticity is believed to be the foundation for learning and memory.[46]STDP is an important kind of long-term plasticity, where the synaptic weight could be adjusted by intervals between pre-synaptic and postsynaptic spikes. It illustrates synaptic learning rules which changes conventional Hebbian synaptic plasticity,and plays a significant role in cognitive behavior.[46]Generally, there are two types of STDP, the symmetric and anti-symmetric Hebbian learning rules.[47]In typical STDP,when ΔT >0,the connection strength will be potentiated or depressed. However,when ΔT <0, the connection strength will be depressed or potentiated.[48]Here,these two types of Hebbian STDP learning rules can be emulated in our IWO-based synaptic transistor. Figure 3(a)shows 6 pair of pre-synaptic and post-synaptic spikes(4.0 V,40 ms)which are applied on the gate and drain electrodes,separately. A reading pulse(0.1 V,20 ms)is used to read the synaptic strength. The change of the synaptic plasticity can be written as

    where W0is the original synaptic strength. The WSTDPis the synaptic strength after STDP measurement.[40]When ΔT >0,long-term potentiation will be formed. On the contrary,when ΔT <0, long-term depression can be formed. Anti-Hebbian STDP can also be realized by applying 6 pair of pre-synaptic and post-synaptic spikes(?4 V,40 ms)on gate and drain electrodes,respectively(Fig.3(b)).

    Fig. 4. (a) A diagram of the biological memory consolidation process.(b)SM and STM can be realized at low frequency inputs. (c)STM to LTM transition by increasing spike numbers. (d) STM to LTM transition by increasing spike amplitudes.

    In biological,the transition of short-term memory(STM)to long-term memory(LTM)was thought as a major learning rule.[49]In 1968, Atkinson and Shiffrin put forward a multistore type of brain memory, as shown in Fig. 4(a).[50]This process illustrates 3 types of memory,sensory memory(SM),short-term memory, and long-term memory. By application of adequate stimulus, SM could transform into STM. Moreover, STM could transform into LTM, too. Frequency dependent EPSC responses are shown in Fig. 4(b). The voltage pulse (4.0 V, 20 ms) is used as repeated stimulus. First,five pre-synaptic spikes(0.2 Hz)are applied on the gate electrode to mimic SM. The peak EPSC values of ~9.0 μA can be observed and each EPSC decays back to the initial current.When applying pre-synaptic spikes with a frequency range from 1.0 Hz to 10 Hz,peak EPSC values will increase due to multi-pulse facilitation,like a series of PPF.However,EPSCs also decay to the initial current when the spikes end. These processes simulate the STM behaviors. Although 100 pulses(4.0 V,20 ms)at 10 Hz are applied on the gate electrode,EPSC will still decay to the original value,as shown in Fig.S3. The transition of LTM is mimicked at the frequency of 25 Hz,as illustrated in Figs.4(c)and 4(d). The EPSC responses with different pulse number under the same pre-synaptic spike(4.0 V,20 ms)are demonstrated in Fig.4(c). EPSC responses change with the variation of the pulse number. LTM can be obtained when the pulse number is larger than 70. In this case, EPSC will not decay back to the initial value. When the gate pulse number is very samll,proton in the chitosan film will migrated to the channel/chitosan interface and induce the accumulation of carriers. However,some protons will be penetrated into the IWO channel layer and cause electrochemical doping when the gate pulse number is large enough. As a result, the channel conductivity will be nonvolatile increased, and LTM can be observed. Some previous reports have already proved that proton permeation and electrochemical doping are the main mechanisms for STM to LTM transition.[35,51,52]STM also can be transformed into LTM by increasing the pre-synaptic spike amplitudes(Fig.4(d)). The pulse number and frequency are fixed at 100 pulses and 25 Hz,respectively. When the amplitude is above 4.0 V, the EPSC will not return to the initial level. Moreover, pulse width dependent synaptic plasticity is also investigated, as shown in Fig. S4. LTM can also be obtained when the pulse width is increased.

    Fig. 5. Classical conditioning experiment. (a) Experimental arrangement and flow sheet for mimicking classical conditioning in an IWO-based synaptic transistor.(b)Similar Pavlovian process realized in an IWO-based synaptic transistor.Vgs of 3.0 V represents food while Vgs of 2.0 V represents bell.

    Classical conditioning,namely,Pavlovian conditioned reflex, which could be acquired by applying a stimulus and an unconditional stimulus to an individual many times.[53]After associative learning, the individual can possess a capacity which induces conditioned responses like unconditional responses while applying the stimulus only. Four essential factors in this experiment are often utilized,unconditioned stimulus(US),unconditioned response(UR),conditioned stimulus(CS),and conditioned response(CR).During Pavlov’s dog experiment,feeding food and ringing bell are called US and CS,respectively. And the salivation caused by US is called UR.Before training,salivation only can be caused by feeding food(US).In the time of conditioning process,the dog was fed with food and ringing bell repeatedly. Thus, the relationship between CS and US is established. As a result,the salivation of the dog can be triggered by CS alone after training. That is to say that the CR is triggered.And the function of US is replaced by CS.It should be noted here that LTP plays an indispensable role in the process of associative learning. With the behavior of LTP, Pavlovian conditioning could be realized on our IWO-based transistors. In the experiment, the voltage pulse(2.0 V,20 ms)with a frequency of 0.5 Hz applied on the gate is considered to be‘ringing bell’(CS)while pre-synaptic spike(3.0 V,20 ms)with a frequency of 0.5 Hz applied on the gate is regarded as‘food’(US),as shown in Figs.5(a)and 5(b). And 1.0 μA of the synaptic weight is set as the threshold. Before conditioning process, 6 US and 6 CS are imposed separately on the gate. When US is applied only, the synaptic weight is over 1.0μA and the unconditioned response is caused. However,the synaptic weight is under threshold when applying CS alone. Then,100 bell stimuli(2 V,20 ms)and 100 food stimuli(3.0 V,20 ms)with a frequency of 25 Hz are utilized on the gate alternately as training spikes, as shown in Fig.5(b). After training, the synaptic weight is increased. In other words,the association behavior between CS and US is built. By application of CS alone, the synaptic weight is above 1.0 μA.That is to say, CS can trigger CR and conditioning reflex is realized. The features of classical conditioning also contain extinction. With the decay of synaptic weight, the salivation response decreases gradually. Conditioned responses will recover to its initial state after ~155 successive CS applying on gate solely,which indicates that the association learning is extinguished. Thus, the classical conditioning is successfully emulated in the IWO-based synaptic transistor.

    4. Conclusion and perspectives

    In summary, IWO-based EDL transistors gated by chitosan-based biopolymer electrolyte were fabricated and proposed for neuromorphic devices. Such multi-terminal neuromorphic devices show good electrical performance. Some basic synaptic functions, including EPSC, PPF, and filtering,were emulated in single IWO-based device. Hebbian STDP and anti-Hebbian STDP learning rules were also emulated by applying different spike protocols. Plasticity transition and classical conditioning were successfully emulated in single device, too. Our results indicate that IWO-based neuromorphic transistors have potential application for brain-like computing and neuromorphic systems.

    猜你喜歡
    劉銳
    《爭暖》
    劉銳作品欣賞
    Diffusion of a chemically active colloidal particle in composite channels
    哈爾濱師范大學(xué)作品賞析
    Buying a New Bird
    《欣欣向榮》《景觀一角之四》《鄉(xiāng)間小景》《家鄉(xiāng)巨變》《山村老人》《幽》
    《欣欣向榮》《景觀一角之四》《鄉(xiāng)間小景》《家鄉(xiāng)巨變》《山村老人》《幽》
    淺析金融危機(jī)化解救助的效果
    智富時代(2017年7期)2017-09-05 13:30:01
    無辜發(fā)小之死:朋友前妻不能追?
    無辜發(fā)小之死:朋友前妻不能追?
    亚洲一卡2卡3卡4卡5卡精品中文| 国内久久婷婷六月综合欲色啪| 精品久久蜜臀av无| 亚洲欧美日韩高清在线视频| 亚洲中文字幕日韩| 国产高清激情床上av| 欧美日韩亚洲综合一区二区三区_| 久久久国产成人免费| 亚洲国产精品久久男人天堂| 国内精品一区二区在线观看| 日韩成人在线观看一区二区三区| a级毛片a级免费在线| 桃红色精品国产亚洲av| 欧美久久黑人一区二区| 成人特级黄色片久久久久久久| 天天躁狠狠躁夜夜躁狠狠躁| 叶爱在线成人免费视频播放| 在线看三级毛片| 麻豆一二三区av精品| 色哟哟哟哟哟哟| 香蕉av资源在线| 大型av网站在线播放| 亚洲一区高清亚洲精品| 亚洲精品av麻豆狂野| 亚洲精品中文字幕在线视频| 免费电影在线观看免费观看| 黄片大片在线免费观看| 国产单亲对白刺激| 色老头精品视频在线观看| 在线视频色国产色| 欧美在线一区亚洲| 欧洲精品卡2卡3卡4卡5卡区| 9191精品国产免费久久| 免费看a级黄色片| 国产一区二区三区在线臀色熟女| bbb黄色大片| 啦啦啦观看免费观看视频高清| 777久久人妻少妇嫩草av网站| 五月伊人婷婷丁香| 亚洲国产精品成人综合色| 99久久精品国产亚洲精品| 看黄色毛片网站| 大型黄色视频在线免费观看| 黄色视频,在线免费观看| 中文字幕精品亚洲无线码一区| 国产精品电影一区二区三区| 精品电影一区二区在线| 亚洲九九香蕉| 欧美另类亚洲清纯唯美| 中文亚洲av片在线观看爽| 一进一出好大好爽视频| 一本一本综合久久| 黄色毛片三级朝国网站| 久久久久久九九精品二区国产 | 国产精品一区二区免费欧美| 99久久久亚洲精品蜜臀av| www.999成人在线观看| 高清毛片免费观看视频网站| 高潮久久久久久久久久久不卡| 国产99白浆流出| 亚洲,欧美精品.| 麻豆av在线久日| av片东京热男人的天堂| 99热这里只有精品一区 | 18禁美女被吸乳视频| 两个人视频免费观看高清| 午夜免费激情av| 最新在线观看一区二区三区| 两个人看的免费小视频| 亚洲av成人一区二区三| 亚洲精品一区av在线观看| 极品教师在线免费播放| 亚洲第一欧美日韩一区二区三区| 久热爱精品视频在线9| 一进一出好大好爽视频| 欧美日韩福利视频一区二区| 99国产精品一区二区三区| 久久久国产欧美日韩av| 欧美zozozo另类| 法律面前人人平等表现在哪些方面| 久久久久国产精品人妻aⅴ院| av欧美777| 久久天躁狠狠躁夜夜2o2o| 国产aⅴ精品一区二区三区波| 午夜两性在线视频| 亚洲精品美女久久av网站| 日韩有码中文字幕| 特级一级黄色大片| 国产蜜桃级精品一区二区三区| 久久精品91无色码中文字幕| 亚洲国产中文字幕在线视频| 欧美三级亚洲精品| 亚洲狠狠婷婷综合久久图片| 久久久久性生活片| 777久久人妻少妇嫩草av网站| 一进一出好大好爽视频| 国产麻豆成人av免费视频| 在线国产一区二区在线| 日韩成人在线观看一区二区三区| 一级片免费观看大全| 正在播放国产对白刺激| 男人舔女人的私密视频| 两个人视频免费观看高清| svipshipincom国产片| 黑人巨大精品欧美一区二区mp4| 1024香蕉在线观看| bbb黄色大片| 黑人操中国人逼视频| 精品久久久久久,| 欧美成人性av电影在线观看| 久久热在线av| 亚洲精品在线观看二区| 母亲3免费完整高清在线观看| 国产激情久久老熟女| 三级男女做爰猛烈吃奶摸视频| 久久中文看片网| 后天国语完整版免费观看| 亚洲精品av麻豆狂野| 最好的美女福利视频网| 久久精品成人免费网站| 中文字幕av在线有码专区| 男女午夜视频在线观看| 日本a在线网址| 欧美日韩亚洲国产一区二区在线观看| 在线观看www视频免费| 久久香蕉国产精品| 特大巨黑吊av在线直播| 亚洲午夜精品一区,二区,三区| 久久国产乱子伦精品免费另类| 最近最新中文字幕大全免费视频| 两个人看的免费小视频| 色在线成人网| 啪啪无遮挡十八禁网站| 看免费av毛片| 人人妻人人澡欧美一区二区| 夜夜爽天天搞| 精品国内亚洲2022精品成人| 18禁黄网站禁片免费观看直播| a级毛片在线看网站| 精品第一国产精品| 亚洲乱码一区二区免费版| 免费人成视频x8x8入口观看| 日本一本二区三区精品| 亚洲精品在线观看二区| 日韩av在线大香蕉| 真人做人爱边吃奶动态| 草草在线视频免费看| 久久九九热精品免费| 99国产精品99久久久久| 男女下面进入的视频免费午夜| www.www免费av| 国产99久久九九免费精品| 精品人妻1区二区| 最近最新中文字幕大全免费视频| 亚洲精品av麻豆狂野| 少妇人妻一区二区三区视频| 后天国语完整版免费观看| 在线观看舔阴道视频| 午夜福利欧美成人| 可以在线观看的亚洲视频| 欧美乱码精品一区二区三区| 国产精品免费一区二区三区在线| 又爽又黄无遮挡网站| av免费在线观看网站| 床上黄色一级片| 成年女人毛片免费观看观看9| 国产精品免费视频内射| 露出奶头的视频| 美女扒开内裤让男人捅视频| 国产精品久久久久久久电影 | 18禁国产床啪视频网站| 成人国语在线视频| 999精品在线视频| 国内毛片毛片毛片毛片毛片| 50天的宝宝边吃奶边哭怎么回事| 啦啦啦免费观看视频1| 久久九九热精品免费| 搡老熟女国产l中国老女人| 色综合亚洲欧美另类图片| 日本一区二区免费在线视频| 少妇熟女aⅴ在线视频| 在线免费观看的www视频| 久久这里只有精品19| 手机成人av网站| 一二三四社区在线视频社区8| 国产区一区二久久| 国产亚洲av高清不卡| 国产精品爽爽va在线观看网站| 婷婷丁香在线五月| 亚洲成人久久性| 欧美日韩亚洲综合一区二区三区_| √禁漫天堂资源中文www| 一进一出抽搐gif免费好疼| 丝袜美腿诱惑在线| 免费在线观看日本一区| 亚洲国产看品久久| 桃红色精品国产亚洲av| 757午夜福利合集在线观看| 国产高清视频在线观看网站| 欧美中文综合在线视频| 最好的美女福利视频网| 精品欧美国产一区二区三| 欧美乱色亚洲激情| 亚洲国产欧美人成| 国产精品久久电影中文字幕| 午夜影院日韩av| 十八禁人妻一区二区| 看黄色毛片网站| 婷婷六月久久综合丁香| 久久精品国产99精品国产亚洲性色| 在线观看免费视频日本深夜| 午夜亚洲福利在线播放| 国产成人av激情在线播放| 久久人人精品亚洲av| 在线观看午夜福利视频| 国内精品一区二区在线观看| 听说在线观看完整版免费高清| 国产高清videossex| 亚洲精品一区av在线观看| 嫁个100分男人电影在线观看| 人人妻人人看人人澡| 两个人免费观看高清视频| 狂野欧美白嫩少妇大欣赏| 曰老女人黄片| 我要搜黄色片| 在线国产一区二区在线| 亚洲精品美女久久av网站| 精品久久久久久成人av| 亚洲成人精品中文字幕电影| 91国产中文字幕| 国产免费男女视频| АⅤ资源中文在线天堂| 日本三级黄在线观看| 国产精品影院久久| 日韩大码丰满熟妇| 国产精品乱码一区二三区的特点| 国产亚洲欧美在线一区二区| 色尼玛亚洲综合影院| 天天躁夜夜躁狠狠躁躁| 欧美色视频一区免费| 亚洲专区字幕在线| 宅男免费午夜| 欧美中文综合在线视频| av国产免费在线观看| 精品熟女少妇八av免费久了| 亚洲中文字幕日韩| 午夜福利在线观看吧| 一本综合久久免费| 国产一区二区在线av高清观看| 色尼玛亚洲综合影院| 最好的美女福利视频网| bbb黄色大片| 熟女电影av网| 精品久久久久久久末码| 757午夜福利合集在线观看| 色综合站精品国产| 高潮久久久久久久久久久不卡| 男女下面进入的视频免费午夜| 午夜老司机福利片| 久久久久久九九精品二区国产 | 日本黄大片高清| 最近最新中文字幕大全免费视频| 亚洲一区二区三区不卡视频| 亚洲av日韩精品久久久久久密| 国产又黄又爽又无遮挡在线| 男女做爰动态图高潮gif福利片| 非洲黑人性xxxx精品又粗又长| 亚洲电影在线观看av| 两个人视频免费观看高清| 一区二区三区国产精品乱码| 一二三四社区在线视频社区8| 日韩欧美在线二视频| 亚洲av成人不卡在线观看播放网| 久99久视频精品免费| 在线a可以看的网站| 国产黄色小视频在线观看| 一级毛片精品| 久久精品影院6| 国内久久婷婷六月综合欲色啪| 久久国产乱子伦精品免费另类| 可以在线观看的亚洲视频| 精品不卡国产一区二区三区| 色播亚洲综合网| 搡老熟女国产l中国老女人| 哪里可以看免费的av片| 夜夜躁狠狠躁天天躁| 日韩 欧美 亚洲 中文字幕| 在线看三级毛片| 禁无遮挡网站| 日韩精品中文字幕看吧| 国产伦人伦偷精品视频| 亚洲国产日韩欧美精品在线观看 | 久久亚洲精品不卡| 人妻久久中文字幕网| av天堂在线播放| 精品欧美国产一区二区三| 精品少妇一区二区三区视频日本电影| 母亲3免费完整高清在线观看| 又黄又粗又硬又大视频| 亚洲人成77777在线视频| 亚洲天堂国产精品一区在线| 国内揄拍国产精品人妻在线| 中出人妻视频一区二区| 午夜免费成人在线视频| 久9热在线精品视频| 一边摸一边做爽爽视频免费| 久久久久国内视频| 黄色成人免费大全| 亚洲国产精品成人综合色| 亚洲自偷自拍图片 自拍| 午夜福利免费观看在线| 99久久综合精品五月天人人| 亚洲欧美日韩无卡精品| 很黄的视频免费| 国产爱豆传媒在线观看 | 日韩欧美国产一区二区入口| 国产成人aa在线观看| 亚洲国产高清在线一区二区三| 精品免费久久久久久久清纯| 亚洲va日本ⅴa欧美va伊人久久| 九九热线精品视视频播放| 亚洲av成人精品一区久久| 草草在线视频免费看| 色av中文字幕| 人人妻,人人澡人人爽秒播| 最近最新免费中文字幕在线| 国产精品98久久久久久宅男小说| 99久久无色码亚洲精品果冻| 亚洲av五月六月丁香网| 欧美在线一区亚洲| 国产精品1区2区在线观看.| 国产成人精品久久二区二区91| 国产精品亚洲美女久久久| 精品久久久久久久毛片微露脸| 人妻丰满熟妇av一区二区三区| 在线永久观看黄色视频| 欧美另类亚洲清纯唯美| 国产精品av视频在线免费观看| 精品午夜福利视频在线观看一区| 国产不卡一卡二| 免费看日本二区| 人人妻人人澡欧美一区二区| 国产精品亚洲av一区麻豆| 欧美又色又爽又黄视频| 很黄的视频免费| 嫩草影视91久久| 亚洲人与动物交配视频| 日韩欧美国产一区二区入口| e午夜精品久久久久久久| 亚洲专区中文字幕在线| 免费在线观看成人毛片| 国产av在哪里看| 国产成人av教育| 欧美+亚洲+日韩+国产| 18禁黄网站禁片午夜丰满| 午夜福利高清视频| 国产熟女午夜一区二区三区| ponron亚洲| 好男人在线观看高清免费视频| 国产99白浆流出| 成年人黄色毛片网站| 国产精品国产高清国产av| 国产成人精品久久二区二区91| 在线十欧美十亚洲十日本专区| 国产黄色小视频在线观看| 搞女人的毛片| 亚洲黑人精品在线| 国产精品一区二区三区四区免费观看 | 日韩精品中文字幕看吧| 久久亚洲真实| 国产视频一区二区在线看| 中国美女看黄片| 精品少妇一区二区三区视频日本电影| 国产亚洲av嫩草精品影院| 亚洲精品在线美女| 麻豆国产av国片精品| 在线观看66精品国产| 久久精品91无色码中文字幕| 亚洲 欧美 日韩 在线 免费| 亚洲一卡2卡3卡4卡5卡精品中文| 97碰自拍视频| 首页视频小说图片口味搜索| 五月伊人婷婷丁香| 亚洲第一电影网av| 亚洲激情在线av| 成人三级做爰电影| 好男人电影高清在线观看| av欧美777| 国产高清激情床上av| 国产成人aa在线观看| 亚洲一区二区三区不卡视频| 国产免费av片在线观看野外av| 在线观看日韩欧美| 人人妻人人看人人澡| 深夜精品福利| 成人亚洲精品av一区二区| 一进一出抽搐gif免费好疼| 亚洲精华国产精华精| 国产激情欧美一区二区| 亚洲片人在线观看| 久久九九热精品免费| 女人爽到高潮嗷嗷叫在线视频| 亚洲激情在线av| 欧美黄色淫秽网站| 三级国产精品欧美在线观看 | 国内毛片毛片毛片毛片毛片| 成人18禁高潮啪啪吃奶动态图| 欧美又色又爽又黄视频| www.www免费av| 又黄又粗又硬又大视频| АⅤ资源中文在线天堂| 亚洲第一电影网av| 欧美在线黄色| 桃色一区二区三区在线观看| 搡老岳熟女国产| 99久久综合精品五月天人人| 国产欧美日韩一区二区三| 九色国产91popny在线| 宅男免费午夜| 脱女人内裤的视频| or卡值多少钱| 国产精品国产高清国产av| 精品久久久久久久末码| 国产99白浆流出| 又大又爽又粗| 精品一区二区三区视频在线观看免费| 给我免费播放毛片高清在线观看| 99久久久亚洲精品蜜臀av| 国产成人一区二区三区免费视频网站| 久久国产乱子伦精品免费另类| 欧美另类亚洲清纯唯美| 久久婷婷人人爽人人干人人爱| 欧美3d第一页| 99国产极品粉嫩在线观看| 最新在线观看一区二区三区| 国产三级在线视频| 免费在线观看亚洲国产| 亚洲精品一区av在线观看| 精品午夜福利视频在线观看一区| 1024香蕉在线观看| 真人做人爱边吃奶动态| 狠狠狠狠99中文字幕| 国语自产精品视频在线第100页| 一本久久中文字幕| 国产爱豆传媒在线观看 | 黄色女人牲交| 中文资源天堂在线| 欧美日韩亚洲综合一区二区三区_| 成人高潮视频无遮挡免费网站| av超薄肉色丝袜交足视频| 激情在线观看视频在线高清| 国产亚洲精品久久久久5区| 亚洲av成人一区二区三| 久久精品影院6| 一本精品99久久精品77| 美女午夜性视频免费| av福利片在线| 动漫黄色视频在线观看| 99精品在免费线老司机午夜| 色哟哟哟哟哟哟| 黄片大片在线免费观看| 麻豆成人av在线观看| 亚洲aⅴ乱码一区二区在线播放 | 国产一区二区在线av高清观看| 国内久久婷婷六月综合欲色啪| 日韩成人在线观看一区二区三区| 狂野欧美白嫩少妇大欣赏| 黑人巨大精品欧美一区二区mp4| 欧美日韩乱码在线| 亚洲国产欧美网| 国产av不卡久久| 中文在线观看免费www的网站 | 欧美丝袜亚洲另类 | 国产探花在线观看一区二区| 国产真人三级小视频在线观看| 中文字幕精品亚洲无线码一区| 日本黄大片高清| 禁无遮挡网站| 女同久久另类99精品国产91| 别揉我奶头~嗯~啊~动态视频| 村上凉子中文字幕在线| 伦理电影免费视频| 九九热线精品视视频播放| 欧美日韩瑟瑟在线播放| 久久午夜亚洲精品久久| 久久国产乱子伦精品免费另类| 国产av一区在线观看免费| 麻豆国产97在线/欧美 | 舔av片在线| 精品福利观看| 欧美人与性动交α欧美精品济南到| 亚洲乱码一区二区免费版| www.熟女人妻精品国产| 麻豆国产97在线/欧美 | 免费看美女性在线毛片视频| 国产亚洲av高清不卡| 国产成人av教育| 日韩精品免费视频一区二区三区| 看免费av毛片| 岛国在线免费视频观看| 欧美三级亚洲精品| 欧美3d第一页| 亚洲男人天堂网一区| 亚洲国产日韩欧美精品在线观看 | 一夜夜www| 一边摸一边做爽爽视频免费| 国内精品久久久久久久电影| 亚洲片人在线观看| 看片在线看免费视频| 亚洲aⅴ乱码一区二区在线播放 | 婷婷丁香在线五月| 一二三四社区在线视频社区8| 一本大道久久a久久精品| 黄片大片在线免费观看| 村上凉子中文字幕在线| 精品第一国产精品| 久久人妻福利社区极品人妻图片| 国产亚洲精品久久久久久毛片| 很黄的视频免费| 在线永久观看黄色视频| 亚洲成av人片在线播放无| 日本 欧美在线| 又粗又爽又猛毛片免费看| 成熟少妇高潮喷水视频| 免费高清视频大片| 国内精品一区二区在线观看| 久久久国产成人免费| 99re在线观看精品视频| 国产精品电影一区二区三区| 久久久久久久精品吃奶| 亚洲专区中文字幕在线| 日本三级黄在线观看| 久久精品综合一区二区三区| 手机成人av网站| 亚洲成人久久爱视频| 国产又色又爽无遮挡免费看| 一级毛片精品| 色精品久久人妻99蜜桃| 人人妻,人人澡人人爽秒播| 日韩欧美国产在线观看| 欧美日韩亚洲综合一区二区三区_| 亚洲成人免费电影在线观看| 首页视频小说图片口味搜索| 国产精品一区二区三区四区久久| 两性午夜刺激爽爽歪歪视频在线观看 | netflix在线观看网站| 1024视频免费在线观看| 久久久久亚洲av毛片大全| 精品久久久久久久久久久久久| 欧美性猛交黑人性爽| 变态另类成人亚洲欧美熟女| 亚洲人成伊人成综合网2020| 宅男免费午夜| 超碰成人久久| av福利片在线| 少妇被粗大的猛进出69影院| netflix在线观看网站| 嫁个100分男人电影在线观看| 亚洲自拍偷在线| 最新美女视频免费是黄的| 久久中文字幕一级| 老汉色∧v一级毛片| 欧美日韩亚洲国产一区二区在线观看| 国产精品日韩av在线免费观看| 久热爱精品视频在线9| aaaaa片日本免费| 免费在线观看完整版高清| 亚洲va日本ⅴa欧美va伊人久久| 午夜精品久久久久久毛片777| 久久亚洲精品不卡| 欧美日本视频| 毛片女人毛片| av在线播放免费不卡| 国产精品野战在线观看| 18美女黄网站色大片免费观看| 男女午夜视频在线观看| 人妻丰满熟妇av一区二区三区| 日韩av在线大香蕉| 午夜福利在线在线| 最近最新中文字幕大全电影3| 搡老妇女老女人老熟妇| 欧美一区二区精品小视频在线| 亚洲第一电影网av| 免费看美女性在线毛片视频| 老司机靠b影院| 久久精品国产99精品国产亚洲性色| 久久亚洲精品不卡| 久久热在线av| 亚洲精品粉嫩美女一区| 久久精品国产综合久久久| 日日干狠狠操夜夜爽| 国产精品国产高清国产av| 久久精品成人免费网站| 国产高清视频在线播放一区| 精品无人区乱码1区二区| 亚洲美女黄片视频| 亚洲精品国产一区二区精华液| 在线免费观看的www视频| 男男h啪啪无遮挡| 欧美成人性av电影在线观看| 一边摸一边做爽爽视频免费| 免费在线观看黄色视频的| 国产在线观看jvid| 久久久久久久久免费视频了| 国产成人精品无人区| 悠悠久久av| 少妇的丰满在线观看| 久久婷婷人人爽人人干人人爱| 亚洲av成人精品一区久久| 成在线人永久免费视频| 国产免费男女视频| 最近最新免费中文字幕在线| 妹子高潮喷水视频| 久久久久性生活片| 一区福利在线观看|