• <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 ?

    Mathematical Analysis of the Meridian System in Traditional Chinese Medicine

    2020-11-03 03:12:04WANXiaoHai
    Digital Chinese Medicine 2020年3期
    關(guān)鍵詞:藝文志靈樞漢書

    WAN Xiao-Hai

    EMD Serono Research & Development Institute,Billerica,Massachusetts 01821-3936,USA

    Keywords

    Meridian system

    Pumping power

    Fluid mechanics

    Human physiology

    Work of breathing

    ABSTRACT

    Energy expenditure of the meridian system in traditional Chinese medicine(TCM)for living human bodies is one of the fundamental questions regarding the physical properties of the meridian system.As a first attempt to address this,24 hand/foot meridians were modeled as a continuous channel with the sustainable movement of Qi and blood inside.Then,the fluid mechanics energy equation for steady and incompressible flow was applied to estimate the pumping power of meridian circulation,based on the meridian length,blood viscosity and circulation velocity.Additional findings based on the pumping power estimation results include:(1)new information to corroborate the determination of the production era of Yellow Emperor’s Inner Classics(Huang Di Nei Jing,《黃帝內(nèi)經(jīng)》);(2)a new definition for work of breathing(WOB)from a TCM perspective.This paper could lead to future research aimed at modernizing the understanding of the meridian system,Qi and TCM using quantitative methods.

    1 Introduction

    The meridian system is an important concept in traditional Chinese medicine(TCM),and it is about a path through which the life-energy,known as Qi flows.I hypothesize that physically,this life-energy Qi represents effective pumping energy,which is defined as,for a given region of interest in the meridian system,the pumping power needed to maintain the flow of Qi.Meridian system is a complex network to connect human body viscera(e.g.,lung,kidney and heart)with the rest of the body.An illustration of the system can be reviewed in Figure 1.As this system is complex,and there is a lack of proper ways to study it quantitatively using modern technology,the meridian system has long been regarded as an abstract concept.Although there is increasing worldwide interest in acupuncture and alternative medicines,there is still much that needs to be learned about the different aspects of the meridian system.

    In this paper,I have applied principles of fluid mechanics to study the pumping power of the meridian system,focusing on the resting human body without inclination,such as while sleeping.My findings include:(1)pumping power estimation of circulation in twelve hand/foot meridians;(2)new information using a mathematical analysis to corroborate the determination of the production era ofYellow Emperor’s Inner Classics(Huang Di Nei Jing,《黃帝內(nèi)經(jīng)》);(3)a new definition for work of breathing(WOB)from a TCM perspective.

    This study is organized as follows.In Section 2,existing data on the meridian system is summarized fromYellow Emperor’s Inner Classics(Huang Di Nei Jing,《黃帝內(nèi)經(jīng)》).Section 3 provides details of the pumping power analysis,and Section 4 discusses and summarizes the findings based on the analysis.Section 5 contains further discussion and the conclusions of the paper.

    2 Data

    According to TCM theory,and more specifically,the principle of Yin and Yang,Qi’s property is regarded as Yang as it represents a moving action.Moreover,blood,which is a general term for living and mobile entities that have material representation in the meridian,not to be confused with blood that flows in arteries and veins,is regarded as Yin.Indeed,what is flowing in the meridian is this blood driven by Qi,or Yin driven by Yang.

    There are 12 hand/foot meridians on each side(left and right)of the human body,and one middle meridian in the front(Yin)and back(Yang).Together,12×2 + 2=26 meridians are of common interest in TCM.The total number of meridians will become 28 if the Yang Heel Vessel(Yang HV)and Yin Heel Vessel(Yin HV)meridians are also included.

    2.1 Unit conversion

    2.1.1 Time unitAs mentioned in reference[1],13 500 standard breathing periods occur in a 24 hour period,with a unit referred to as “Xi” in Chinese.Therefore,one can deduce that one standard breathing period takes 24×3 600/13 500=6.4 seconds(s),which includes inspiration,expiration and a pause in between.Note that a breathing period in modern medicine usually includes around 2 s for inhalation,and 3 s for exhalation[2],which would add up to 5 s.Therefore,we can deduce that the pause between inspiration and expiration lasts about 1.4 s.

    2.1.2 Length unitInYellow Emperor’s Inner Classics(Huang Di Nei Jing,《黃帝內(nèi)經(jīng)》),length unit “Chi”has a long history of use in China and could refer to quite different physical lengths during different historical periods[3,4].According to reference[4],conversion of 1 “Chi” to centimeters(cm)and feet(ft)are summarized in Table 1,which includes the Chinese dynasties before or around the time when the bookYellow Emperor’s Inner Classics(Huang Di Nei Jing,《黃帝內(nèi)經(jīng)》)was conceived.

    Table 1 Conversion of 1 “Chi” to centimeters(cm)and feet(ft)in the Shang,Zhou,Qin and Han dynasties

    2.2 Meridians' length

    According to reference[1],the length data for each of the 12 meridians are listed in Table 2.

    3 Analysis

    3.1 Meridians' circulation time and speed

    The Qi takes 270 standard breathing periods(or 270×6.4/3 600=0.48 hours(h))to complete one full cycle through the 28(and more)meridians[1,5].Therefore,in a single day and night,the Qi completes 13 500/270=50 cycles.On average,the circulation speedVavgis 162/0.48=337.5 “Chi”/h,or 0.052(Shang dynasty),0.061(Zhou dynasty),0.071(Qin dynasty),0.066 - 0.073(Han dynasty)ft/s,if the length unit“Chi” is converted based on the unit conversion rule for each dynasty in Table 1.

    The two middle meridians and the Yin/Yang HV meridians belong to eight extraordinary meridians,and they do not have a corresponding visceral manifestation in TCM theory.For analysis purposes,I choose to focus on Qi’s flow within the 12(or 24 for both the left and right side)meridians,which all have visceral manifestations.

    Although it may seem not intuitive,Qi’s flow is assumed to be sequential,from the left side(Yang)to the right side(Yin)and continues without stopping such that life-supporting subsystems can run.On each side of the body,according to midnight-noon and ebb-flow doctrine,the flow happens sequentially in the following order:(1)hand-Yin-lung;(2)hand-Yang-large intestine;(3)foot-Yang-stomach;(4)foot-Yin-spleen;(5)hand-Yin-heart;(6)hand-Yang-small intestine;(7)foot-Yang-bladder;(8)foot-Yin-kidney;(9)hand-Yin-heart sac;(10)hand-Yangtriple energizer;(11)foot-Yang-gall; and(12)foot-Yin-liver.The incoming connection between the left and right sides is assumed to be the following:(1)left-foot-Yin-liver; and(2)right-hand-Yin-lung.The outgoing connection between the right and left sides is assumed to be the following:(1)right-foot-Yin-liver; and(2)left-hand-Yin-lung.This completes the description of the sequential flow of Qi within the 12 meridians.In the following analysis,I assumed that the average circulation speedVavgis the same as those estimated based on 28 meridians data,even though additional meridians such as the eight extraordinary meridians and others are not considered.

    Table 2 Length data for 12 meridians(unit:“Chi”)

    Note that the assumption of the sequential flow of Qi from the left side to the right side does affect the pumping power estimation.As an example,if the flow of Qi is indeed parallel,and it happens concurrently at both the left and right sides of the body,then this would lead to a different interpretation of one full circulation cycle through the 28 meridians in TCM theory.As a result,it would impact the calculation of the meridian circulation time and speed,as demonstrated in this section.Nevertheless,it seems to be reasonable to assume that the one full circulation cycle in TCM theory is meant for Qi’s flow sequentially through all branches of the meridian system,namely a Lagrangian specification of its flow field.

    3.2 Pumping power estimation

    As the flow of Qi is assumed to be sequential,it is modeled as fluid flow inside a circular pipe.The energy equation for steady flow inside the pipe was calculated,in terms of the heads as(Eq.5-74 in reference[6]):

    wherePi(i=1,2)is the static pressure,ρiis the density of the blood,gis the gravitational acceleration constant on earth,Viis the flow velocity,ziis the hydrostatic head,hpump,uis useful head delivered to the flow,hturbine,eis the extracted head removed from the flow,andhLis the irreversible head loss between meridian location 1 and 2 due to all components of the meridian system,other than the pump or turbine.I further assumed that there was no pump(for the power analysis using the energy equation)and turbine in the meridian system.As this paper focuses on the resting human body without inclination,such as sleeping on a flatbed at nighttime,there is no hydrostatic head,zi.If the flow is steady with a constant velocity,Vavg,the power equation is:

    If the density of the blood is assumed to be the same asρbetween the meridian location 1 and 2,the power equation becomes:

    where ΔP=P1-P2is the pressure loss between the meridian locations 1 and 2 according to the fluid mechanics terminology[6].

    If the cross-sectional shape of the meridian is assumed to be circular with a constant diameterD,the volume flow rate of the meridian therefore is:

    whereVavgis the average circulation speed,andAcis the cross-sectional area of the meridian.So,the required pumping power to overcome this pressure loss is determined by:

    If the meridian’s circulation is mostly laminar,according to Poiseuille’s law[6],the pressure loss(due to frictional force)for a constant circulation speedVavgis(Eq.8-20 in reference[6]):

    it turns out that the corresponding pumping power is:

    whereμis the dynamic blood viscosity,andLis the meridian length.It is interesting to see that diameterDcancels out in this formulation,and pumping power is a function ofVavg,μandL.

    In our case,L=138 "Chi" for the 24 hand/foot meridians.Therefore the corresponding pumping power delivered to the meridian is:

    To continue with the analysis,the blood dynamic viscosityμassumes a value of(3 ~ 4)×10-3Pa·s[7].Therefore,the pumping power was calculated to be(4.4 ~ 5.9)×10-4(Shang dynasty),(7.1 ~ 9.5)×10-4(Zhou dynasty),(1.1 ~ 1.5)×10-3(Qin dynasty),and(0.9 ~ 1.2)×10-3-(1.2 ~ 1.6)×10-3(Han dynasty)watts.Furthermore,if 28 meridians are considered,and one assumes that the sequential channel model still holds true,L=162 “Chi”.Then,the pumping power for this total meridian length is(5.2 ~ 6.9)×10-4(Shang dynasty),(8.4 ~ 11.2)×10-4(Zhou dynasty),(1.3 ~ 1.8)×10-3(Qin dynasty),and(1.1 ~ 1.4)×10-3-(1.4 ~ 1.9)×10-3(Han dynasty)watts.The pumping power required to keep Qi flowing in the meridian system has been estimated to have a possible range of 4.4×10-4- 1.9×10-3watts.

    4 Further Findings

    Based on the estimates in Section 3,further findings are presented below.

    4.1 New information about the Yellow Emperor’s Inner Classics( Huang Di Nei Jing,《黃帝內(nèi)經(jīng)》)production era

    Yellow Emperor’s Inner Classics(Huang Di Nei Jing,《黃帝內(nèi)經(jīng)》)is considered to date the earliest book of medicine in China.It provides a foundation of TCM theory.However,due to its long history,it is not known exactly when the book was written.Based on TCM literature,this book was first recorded in another book calledHan Shu · Treatise on Literature(Han Shu · Yi Wen Zhi,《漢書·藝文志》),which itself is considered to be the earliest history directory book in China.Therefore,it is clear thatYellow Emperor’s Inner Classics(Huang Di Nei Jing,《黃帝內(nèi)經(jīng)》)must have been written during the Han dynasty or even earlier.Interestingly,the estimate of pumping power in Section 3 could shed some light on this.Here,I will start with information about the power of breathing,a quantity which is measured in modern medical studies to check lung function.

    In a normal person at rest,the power of breathing per liter of ventilation has been measured to be about 2.4 J/min[8]or 0.040 08 watts.For a standard breathing period that usually lasts 6.4 s(Section 2),with an associated tidal volume of 500 mL[9],the power of breathing turns out to be 3.13×10-3watts.

    According to the knowledge of human physiology[10,11],the WOB is divided into elastic work and resistive work.Elastic work is the energy required to overcome elastic forces,including lung elastic recoil and surface tension of alveoli,and is stored as elastic potential energy.Resistive work is due to the energy required to overcome frictional forces between tissue and between gas molecules.

    About 65% of the total work is elastic work,while 35% of the total work is resistive[10,11].

    InYellow Emperor’s Inner Classics · Miraculous Pivot(Huang Di Nei Jing·Ling Shu,《黃帝內(nèi)經(jīng)·靈樞》),relationship between breathing and meridian circulation is well documented.For example,1 “Xi” is comprised of one inspiration and one expiration.During one inspiration,meridian circulates by 3“Cun”.Similarly,during one expiration,meridian also circulates by 3 “Cun”.Therefore,it is stated that 1 “Xi” leads to 6 “Cun” circulations of the meridian,implying that there is no movement of meridian circulation during the pause between breathing.As Qi takes 270 “Xi” to complete one full cycle through the meridian system,it can be verified that the distance of such circulation equals 270×6 “Cun”=162 “Chi”,which matches with the 28 meridians’length in Section 2.2.Therefore,based on TCM theory,it is reasonable to assume that the energy spent during breathing includes the energy to sustain the circulation of the meridian system.

    Furthermore,if the resistive work during breathing is indeed close to the work to overcome viscous force in the meridian,one would expect that:

    This would dictate that the length unit “Chi” used extensively inYellow Emperor’s Inner Classics(Huang Di Nei Jing,《黃帝內(nèi)經(jīng)》)should allow for the matching of the estimated pumping power and breathing power measured in modern times.Indeed,1.1×10-3watts coincides exactly with the estimated pumping power in Section 3 with the Han dynasty and a blood dynamic viscosity value of 3×10-3Pa·s.It can be seen in Figure 2,that the pumping power estimates from the Shang dynasty are not as close as those estimates from the Zhou,Qin and Han dynasties,regarding the power of breathing.Therefore,one can deduce that “Chi,” as written in the book,was more likely the length unit commonly used in the Zhou,Qin and Han dynasties as opposed to the Shang dynasty.It is a surprising,yet powerful finding that this mathematical analysis could shed some light on questions usually addressed by archaeology,language science and the astronomical calendar.

    Although one of the estimates of the Han dynasty can be considered closest to the estimate from the power of breathing,the Zhou and Qin dynasties cannot be excluded since the range of their estimates is also close to the line representing 35% of breathing power.

    The horizontal line represents 35% of the breathing power.

    4.2 New definition for WOB

    Another finding that could be deduced from the pumping power estimate is the WOB.WOB is defined as the energy spent to inhale and exhale a breathing gas,and is an important indicator for scientific and medical research,especially in respiratory-related medicine.The pumping power of the meridian system takes up a substantial amount(~ 35%)of the power of breathing.Therefore,from a TCM perspective,WOB should be defined as the energy spent to allow Qi to flow in the meridian system,plus the non-meridian excitation energy during a breathing period.WOB,as discussed earlier,is comprised of two components,one is the resistive work or pumping power of the meridian system,and the other is elastic work,or non-meridian excitation power,such as stretching of the lung.

    5 Discussion and Conclusions

    This paper has presented a novel approach to analyze the meridian system using the principles of fluid mechanics.Although it is not a new idea to study meridian systems using computational fluid dynamic techniques,it is,to the best of our knowledge,the first time that the meridian system has been holistically analyzed using fluid mechanic principles.This paper has demonstrated the scientific validity of such an analysis and could provide insights into the physical properties of the meridian system in humans.This work could also be the basis for future research on TCM using quantitative methods.

    A limitation of this paper is using averaged estimations due to the lack of individual subject level data,a potential extension of the current work is to measure the viscosity of blood(or interstitium related to the meridian)and breathing power on the same subjects to assess potential subject level variability,and fine-tune the relationship between the meridian pumping power and breathing power.This could lead to a more precise determination of theYellow Emperor’s Inner Classics(Huang Di Nei Jing,《黃帝內(nèi)經(jīng)》)production era.This paper also does not consider geometry of the meridian system and further work is required to understand the impact of gravitational force on pumping power estimation.

    In conclusion,this paper has estimated the pumping energy of 12 hand/foot meridians in the range of 4.4×10-4- 1.9×10-3watts.Based on the pumping energy estimate,it is deduced thatYellow Emperor’s Inner Classics(Huang Di Nei Jing,《黃帝內(nèi)經(jīng)》)was more likely conceived in the Zhou,Qin and Han dynasties as opposed to the Shang dynasty.A new definition for WOB was also introduced from a TCM perspective.

    Competing Interests

    The author is currently employed by EMD Serono Research & Development Institute(Merck KGaA subsidiary in the United States)as a global group leader in biostatistics.This paper reflects the personal work and views of the author and does not relate to or represent the company’s views or policies,nor does it relate to the resources at the company.The author declares no conflict of interest.

    猜你喜歡
    藝文志靈樞漢書
    古今字研究應(yīng)該重視出土文獻(xiàn)*——以顏師古《漢書注》古今字研究為例
    懸梁刺股
    《明史·藝文志》史部地理類訂誤十一則
    天一閣文叢(2020年0期)2020-11-05 08:28:30
    黃帝內(nèi)經(jīng) 靈樞·始終(下)
    黃帝內(nèi)經(jīng) 靈樞·始終(上)
    李學(xué)勤《〈漢書·李尋傳〉與緯學(xué)的興起》手稿
    黃帝內(nèi)經(jīng) 靈樞·針解
    黃帝內(nèi)經(jīng) 靈樞·本輸(下)
    《南明史·藝文志》經(jīng)部著錄標(biāo)準(zhǔn)商榷
    天一閣文叢(2014年1期)2014-10-13 08:00:06
    《漢書·藝文志》“輯而論篹”句釋說——“論語”二字話
    一级二级三级毛片免费看| 亚洲在久久综合| 五月开心婷婷网| 寂寞人妻少妇视频99o| av免费观看日本| 最新中文字幕久久久久| 一级二级三级毛片免费看| 熟女人妻精品中文字幕| 国产高清三级在线| 亚洲欧美成人精品一区二区| 日本-黄色视频高清免费观看| 国产一区二区三区av在线| 免费久久久久久久精品成人欧美视频 | 日本猛色少妇xxxxx猛交久久| 日日摸夜夜添夜夜爱| 国产 精品1| 丝袜喷水一区| 欧美区成人在线视频| 久久女婷五月综合色啪小说| 老司机影院毛片| 男的添女的下面高潮视频| 亚洲天堂av无毛| 国产极品粉嫩免费观看在线 | 国产精品一区二区在线观看99| 国产在线免费精品| 欧美区成人在线视频| 日本-黄色视频高清免费观看| 欧美精品人与动牲交sv欧美| 国产精品无大码| 亚洲av.av天堂| 国产精品三级大全| 9色porny在线观看| 国产免费视频播放在线视频| 五月天丁香电影| 啦啦啦啦在线视频资源| 国产淫语在线视频| 我的老师免费观看完整版| 我的女老师完整版在线观看| av国产久精品久网站免费入址| 免费黄网站久久成人精品| 国产成人freesex在线| 久久99蜜桃精品久久| 久久久精品94久久精品| 在线 av 中文字幕| 久久国产精品男人的天堂亚洲 | 国产成人一区二区在线| 欧美日韩视频精品一区| 久久午夜综合久久蜜桃| 狂野欧美白嫩少妇大欣赏| 久久狼人影院| 亚洲av国产av综合av卡| 日本猛色少妇xxxxx猛交久久| 亚洲精品日本国产第一区| 99热这里只有是精品50| 女人久久www免费人成看片| 街头女战士在线观看网站| 亚洲欧洲日产国产| 久久人人爽人人片av| 欧美变态另类bdsm刘玥| 一级,二级,三级黄色视频| 欧美国产精品一级二级三级 | 久久国产乱子免费精品| 日韩成人av中文字幕在线观看| 日韩一区二区三区影片| 欧美激情国产日韩精品一区| 中文欧美无线码| 日韩强制内射视频| 超碰97精品在线观看| 久久av网站| 只有这里有精品99| 精品少妇久久久久久888优播| 日日摸夜夜添夜夜添av毛片| 免费观看a级毛片全部| 青青草视频在线视频观看| 性色av一级| 伦精品一区二区三区| 在线观看免费日韩欧美大片 | 欧美日韩av久久| 国产色爽女视频免费观看| av.在线天堂| 亚洲一级一片aⅴ在线观看| 啦啦啦在线观看免费高清www| 91精品国产国语对白视频| 免费观看的影片在线观看| 亚洲成人一二三区av| 人人妻人人看人人澡| 亚洲av欧美aⅴ国产| 大片电影免费在线观看免费| a 毛片基地| 人妻 亚洲 视频| 日韩欧美 国产精品| 亚州av有码| 美女cb高潮喷水在线观看| 又黄又爽又刺激的免费视频.| 在线天堂最新版资源| 我的女老师完整版在线观看| 狂野欧美激情性bbbbbb| 成人午夜精彩视频在线观看| 亚洲精品,欧美精品| 国产亚洲最大av| 亚洲人与动物交配视频| 亚洲精华国产精华液的使用体验| 日本av免费视频播放| 亚洲国产精品一区三区| 免费看av在线观看网站| 精品人妻熟女毛片av久久网站| 男人舔奶头视频| 夫妻午夜视频| 久久精品久久久久久久性| 人人妻人人爽人人添夜夜欢视频 | 水蜜桃什么品种好| 国产伦理片在线播放av一区| 91aial.com中文字幕在线观看| 97在线视频观看| 51国产日韩欧美| 少妇被粗大的猛进出69影院 | 国产欧美日韩精品一区二区| 国产永久视频网站| 亚洲情色 制服丝袜| 国产亚洲一区二区精品| 国产精品一区二区在线观看99| 国产伦精品一区二区三区视频9| 一二三四中文在线观看免费高清| 在线亚洲精品国产二区图片欧美 | 99久久精品热视频| 大香蕉97超碰在线| 午夜视频国产福利| 成人黄色视频免费在线看| 久久人人爽av亚洲精品天堂| 国产精品久久久久久久久免| 亚洲成色77777| 久久久久久伊人网av| 亚洲四区av| 国产淫语在线视频| 69精品国产乱码久久久| 2021少妇久久久久久久久久久| 夜夜爽夜夜爽视频| 国产极品天堂在线| 人人澡人人妻人| 特大巨黑吊av在线直播| 久久女婷五月综合色啪小说| 欧美精品国产亚洲| 简卡轻食公司| 亚洲,欧美,日韩| 国产精品成人在线| 精品久久久久久久久av| 91久久精品国产一区二区三区| 国产精品久久久久久精品电影小说| 国产精品蜜桃在线观看| 国产在线一区二区三区精| 九草在线视频观看| 如日韩欧美国产精品一区二区三区 | 精品久久久久久久久av| 日本猛色少妇xxxxx猛交久久| 成人漫画全彩无遮挡| 国产淫片久久久久久久久| 久久久久久久国产电影| 日韩视频在线欧美| 日韩熟女老妇一区二区性免费视频| 日韩av在线免费看完整版不卡| 七月丁香在线播放| av国产精品久久久久影院| 国产 精品1| 久久久国产欧美日韩av| 午夜福利,免费看| 一级,二级,三级黄色视频| 97在线视频观看| 免费看av在线观看网站| 夜夜看夜夜爽夜夜摸| 亚洲欧洲日产国产| 成人二区视频| 在线天堂最新版资源| 啦啦啦在线观看免费高清www| 狂野欧美白嫩少妇大欣赏| 久久久久久久久久成人| 久久精品久久久久久噜噜老黄| 精品卡一卡二卡四卡免费| av在线app专区| 大话2 男鬼变身卡| 国产成人a∨麻豆精品| 精品久久久噜噜| 亚洲精品日韩在线中文字幕| 久久 成人 亚洲| 精品人妻一区二区三区麻豆| 日韩一本色道免费dvd| 日韩成人av中文字幕在线观看| 国产深夜福利视频在线观看| 国产成人精品久久久久久| 免费av中文字幕在线| 日本黄色片子视频| 久久人妻熟女aⅴ| 一边亲一边摸免费视频| 极品教师在线视频| 亚洲电影在线观看av| √禁漫天堂资源中文www| 亚洲成人一二三区av| 黄色日韩在线| 噜噜噜噜噜久久久久久91| 赤兔流量卡办理| 日本色播在线视频| 曰老女人黄片| 精品酒店卫生间| 人人妻人人澡人人看| 亚洲国产精品成人久久小说| 成年人免费黄色播放视频 | 在线观看www视频免费| 欧美激情极品国产一区二区三区 | 美女主播在线视频| 国产高清有码在线观看视频| 晚上一个人看的免费电影| 亚洲成色77777| 亚洲天堂av无毛| 91精品伊人久久大香线蕉| 亚洲第一av免费看| 午夜av观看不卡| av国产久精品久网站免费入址| 久久久国产精品麻豆| 我的女老师完整版在线观看| 国产亚洲一区二区精品| 永久免费av网站大全| av国产精品久久久久影院| 少妇精品久久久久久久| 国产午夜精品久久久久久一区二区三区| 国产高清有码在线观看视频| 午夜免费观看性视频| 免费观看a级毛片全部| 夜夜骑夜夜射夜夜干| 日韩欧美一区视频在线观看 | 中文字幕亚洲精品专区| av网站免费在线观看视频| 久久青草综合色| 丝袜喷水一区| 最黄视频免费看| 大香蕉97超碰在线| av有码第一页| 国产男女内射视频| 九九爱精品视频在线观看| 三级国产精品欧美在线观看| 中文字幕av电影在线播放| 99热这里只有是精品50| 国内揄拍国产精品人妻在线| 性色av一级| 国产精品久久久久久久电影| 国产免费视频播放在线视频| 欧美高清成人免费视频www| 视频区图区小说| a 毛片基地| 色94色欧美一区二区| 2018国产大陆天天弄谢| 亚洲精品乱码久久久v下载方式| 伊人亚洲综合成人网| 日本爱情动作片www.在线观看| 久久精品国产鲁丝片午夜精品| 一级,二级,三级黄色视频| 久久精品久久精品一区二区三区| 国产午夜精品一二区理论片| 99久久中文字幕三级久久日本| 少妇熟女欧美另类| 国产精品一区二区性色av| 免费观看性生交大片5| 午夜影院在线不卡| 搡女人真爽免费视频火全软件| 国产精品久久久久久精品电影小说| 免费大片黄手机在线观看| 一边亲一边摸免费视频| 欧美日韩亚洲高清精品| 日日啪夜夜撸| 一级毛片我不卡| 人妻一区二区av| 亚洲自偷自拍三级| 涩涩av久久男人的天堂| 99热国产这里只有精品6| 简卡轻食公司| 人体艺术视频欧美日本| 中文字幕av电影在线播放| 国产伦精品一区二区三区四那| 亚洲美女视频黄频| 国产69精品久久久久777片| 全区人妻精品视频| 久久青草综合色| av专区在线播放| 国产一区二区在线观看av| 韩国av在线不卡| 午夜日本视频在线| 我要看黄色一级片免费的| 亚洲无线观看免费| 精品一区在线观看国产| 黄色欧美视频在线观看| 18禁裸乳无遮挡动漫免费视频| 欧美日韩亚洲高清精品| 男人舔奶头视频| 国内精品宾馆在线| 国产av一区二区精品久久| 天堂中文最新版在线下载| 久久精品国产自在天天线| 夜夜看夜夜爽夜夜摸| 少妇人妻久久综合中文| 亚洲欧美清纯卡通| 国产日韩欧美在线精品| 午夜日本视频在线| 亚洲,一卡二卡三卡| 女的被弄到高潮叫床怎么办| 免费av不卡在线播放| 久久精品国产自在天天线| 国产精品女同一区二区软件| 欧美 日韩 精品 国产| 老司机影院毛片| 国产精品欧美亚洲77777| 色视频www国产| 久久久国产精品麻豆| 一级毛片电影观看| 国产美女午夜福利| 国产精品人妻久久久久久| 只有这里有精品99| 天堂8中文在线网| 秋霞伦理黄片| 亚洲中文av在线| 日本猛色少妇xxxxx猛交久久| 欧美日韩亚洲高清精品| 肉色欧美久久久久久久蜜桃| 午夜久久久在线观看| 国产69精品久久久久777片| 18+在线观看网站| 天天操日日干夜夜撸| 激情五月婷婷亚洲| 少妇人妻精品综合一区二区| 欧美老熟妇乱子伦牲交| 一区在线观看完整版| 国精品久久久久久国模美| 国产精品久久久久久久久免| 亚洲在久久综合| av免费观看日本| 国产成人a∨麻豆精品| 老熟女久久久| 久久国产精品大桥未久av | 久久 成人 亚洲| 亚洲av成人精品一区久久| 亚洲精品乱码久久久久久按摩| 久久精品久久久久久久性| 中国美白少妇内射xxxbb| 3wmmmm亚洲av在线观看| 美女cb高潮喷水在线观看| 国产成人午夜福利电影在线观看| 亚洲熟女精品中文字幕| 丰满少妇做爰视频| h视频一区二区三区| 亚洲美女黄色视频免费看| 日韩欧美精品免费久久| 亚洲人成网站在线观看播放| 自拍偷自拍亚洲精品老妇| 中文字幕av电影在线播放| 成人综合一区亚洲| 最黄视频免费看| 亚洲国产色片| 国产一区二区三区综合在线观看 | 人人妻人人爽人人添夜夜欢视频 | 久久狼人影院| 亚洲内射少妇av| 日本欧美视频一区| 九色成人免费人妻av| 观看免费一级毛片| 丰满人妻一区二区三区视频av| 99久久人妻综合| 欧美bdsm另类| 九九爱精品视频在线观看| 精品久久久久久久久亚洲| 一级av片app| 深夜a级毛片| 在线观看www视频免费| 国产亚洲5aaaaa淫片| 精品人妻熟女av久视频| 欧美精品一区二区大全| 99热全是精品| av播播在线观看一区| 一级黄片播放器| 国产黄色免费在线视频| 亚洲成人一二三区av| 久久99蜜桃精品久久| 亚洲欧美清纯卡通| 久久久精品免费免费高清| 国产一区二区在线观看日韩| 久久99精品国语久久久| 亚洲美女黄色视频免费看| 校园人妻丝袜中文字幕| 日本爱情动作片www.在线观看| 大片免费播放器 马上看| 美女中出高潮动态图| 亚洲精品日韩av片在线观看| 99久国产av精品国产电影| 亚洲欧美日韩东京热| 国产亚洲欧美精品永久| 狠狠精品人妻久久久久久综合| 成人毛片a级毛片在线播放| av在线播放精品| 国产欧美日韩精品一区二区| 久久精品久久久久久噜噜老黄| 亚洲欧美中文字幕日韩二区| 久久久久久久久久久丰满| 亚洲精品自拍成人| 成人影院久久| av线在线观看网站| 亚洲欧美一区二区三区黑人 | av福利片在线观看| 天堂8中文在线网| 一级爰片在线观看| 国产欧美另类精品又又久久亚洲欧美| 国产精品伦人一区二区| freevideosex欧美| 亚洲精品成人av观看孕妇| 亚洲经典国产精华液单| 天美传媒精品一区二区| 两个人免费观看高清视频 | av线在线观看网站| 在线观看免费日韩欧美大片 | 99九九在线精品视频 | 高清不卡的av网站| 久久毛片免费看一区二区三区| 国产精品秋霞免费鲁丝片| 中文字幕亚洲精品专区| 男人舔奶头视频| 天堂俺去俺来也www色官网| 国产有黄有色有爽视频| 日本猛色少妇xxxxx猛交久久| 久久精品熟女亚洲av麻豆精品| 搡女人真爽免费视频火全软件| 日日啪夜夜爽| 久久国产乱子免费精品| 97精品久久久久久久久久精品| 91久久精品电影网| 午夜91福利影院| 亚洲电影在线观看av| 国产av国产精品国产| 少妇被粗大的猛进出69影院 | 妹子高潮喷水视频| 亚洲国产精品一区二区三区在线| 曰老女人黄片| 亚洲电影在线观看av| 国产综合精华液| 日韩视频在线欧美| 又大又黄又爽视频免费| 91成人精品电影| 国产 一区精品| 亚洲国产成人一精品久久久| 一区二区三区精品91| 久久久久网色| 欧美精品人与动牲交sv欧美| 精品久久久精品久久久| www.av在线官网国产| 久久国产亚洲av麻豆专区| 午夜免费男女啪啪视频观看| 天堂8中文在线网| 两个人免费观看高清视频 | 精品人妻一区二区三区麻豆| 2018国产大陆天天弄谢| 亚洲性久久影院| 热re99久久国产66热| 夜夜看夜夜爽夜夜摸| 丝袜脚勾引网站| 国产av精品麻豆| 丰满迷人的少妇在线观看| 在线观看一区二区三区激情| 亚洲国产av新网站| 在线观看人妻少妇| 极品人妻少妇av视频| 伊人久久国产一区二区| 五月伊人婷婷丁香| 51国产日韩欧美| 亚洲欧美精品专区久久| 狂野欧美白嫩少妇大欣赏| 如日韩欧美国产精品一区二区三区 | 日韩一本色道免费dvd| 欧美性感艳星| 亚洲欧美成人精品一区二区| 日韩三级伦理在线观看| 国产av一区二区精品久久| 欧美精品国产亚洲| 亚洲性久久影院| 人人澡人人妻人| 亚洲经典国产精华液单| 日本av手机在线免费观看| 黄色配什么色好看| 亚洲色图综合在线观看| 97在线人人人人妻| 九色成人免费人妻av| 中文在线观看免费www的网站| 亚洲国产欧美在线一区| 国产日韩欧美亚洲二区| 日本猛色少妇xxxxx猛交久久| 又爽又黄a免费视频| 亚洲天堂av无毛| 精品亚洲成a人片在线观看| 婷婷色综合大香蕉| 在线观看人妻少妇| 日本vs欧美在线观看视频 | 91午夜精品亚洲一区二区三区| 丰满饥渴人妻一区二区三| 亚洲精品视频女| 好男人视频免费观看在线| 高清黄色对白视频在线免费看 | 日韩av不卡免费在线播放| 妹子高潮喷水视频| av播播在线观看一区| 久久久久久久久久久丰满| 五月玫瑰六月丁香| 丝袜喷水一区| 桃花免费在线播放| 涩涩av久久男人的天堂| a级毛片在线看网站| 高清av免费在线| 国产色婷婷99| 黄色怎么调成土黄色| 欧美最新免费一区二区三区| 成人无遮挡网站| 成人毛片60女人毛片免费| 国产老妇伦熟女老妇高清| 成人黄色视频免费在线看| 99热6这里只有精品| 亚洲欧洲国产日韩| 精品人妻熟女av久视频| 久久久久久久久久人人人人人人| 日韩av免费高清视频| 又黄又爽又刺激的免费视频.| 亚洲精品久久久久久婷婷小说| 黄色视频在线播放观看不卡| 日韩,欧美,国产一区二区三区| 夫妻午夜视频| 欧美激情极品国产一区二区三区 | av网站免费在线观看视频| 亚洲四区av| 欧美精品一区二区免费开放| 亚洲精品成人av观看孕妇| 一区二区av电影网| 97在线人人人人妻| 国产日韩一区二区三区精品不卡 | 观看免费一级毛片| www.色视频.com| 欧美成人午夜免费资源| av福利片在线| 亚洲av成人精品一区久久| 国产精品免费大片| www.av在线官网国产| 午夜福利视频精品| 久久久久久久久久久久大奶| 国产淫片久久久久久久久| 永久网站在线| 亚洲四区av| 欧美三级亚洲精品| 亚洲精品中文字幕在线视频 | 免费观看的影片在线观看| 亚洲成色77777| 男男h啪啪无遮挡| 久久免费观看电影| 国产精品久久久久久精品电影小说| 69精品国产乱码久久久| 如何舔出高潮| 国产亚洲欧美精品永久| h视频一区二区三区| 久久精品久久精品一区二区三区| 成年人免费黄色播放视频 | 国产成人午夜福利电影在线观看| 国产一区亚洲一区在线观看| 午夜福利,免费看| 我要看日韩黄色一级片| 尾随美女入室| 青青草视频在线视频观看| 老司机影院毛片| 国语对白做爰xxxⅹ性视频网站| 日韩人妻高清精品专区| 中文精品一卡2卡3卡4更新| 99久久精品一区二区三区| 亚洲自偷自拍三级| 精品少妇黑人巨大在线播放| 91在线精品国自产拍蜜月| 人妻夜夜爽99麻豆av| 国产黄色视频一区二区在线观看| 最新中文字幕久久久久| 色视频www国产| 十分钟在线观看高清视频www | 在线天堂最新版资源| 热re99久久精品国产66热6| 国产精品福利在线免费观看| 在线看a的网站| 99国产精品免费福利视频| 黄色怎么调成土黄色| av有码第一页| 久久久久国产精品人妻一区二区| 最近中文字幕2019免费版| 啦啦啦啦在线视频资源| 少妇人妻一区二区三区视频| 青春草视频在线免费观看| 国产一区亚洲一区在线观看| 黄色配什么色好看| 在线观看免费高清a一片| 婷婷色麻豆天堂久久| 精品人妻熟女av久视频| 国产成人91sexporn| 日韩在线高清观看一区二区三区| 日韩成人av中文字幕在线观看| 夜夜看夜夜爽夜夜摸| 免费观看的影片在线观看| av.在线天堂| 嘟嘟电影网在线观看| 26uuu在线亚洲综合色| 国产精品国产av在线观看| 久久ye,这里只有精品| 肉色欧美久久久久久久蜜桃| 国产老妇伦熟女老妇高清| 少妇人妻 视频| 丁香六月天网| 久久青草综合色| 精品国产一区二区三区久久久樱花| 国产无遮挡羞羞视频在线观看| 观看av在线不卡| 日韩一区二区视频免费看| 多毛熟女@视频|