深水气田长距离混输模式下水相运动规律研究

陵水25-1深水气田混输管道距离长、管道爬坡段坡度大,初始投产阶段混输流体水相到达平台的时间长且预测困难,给管道安全运行带来风险。基于多相流计算模型,运用LedaFlow软件,对陵水25-1深水气田初始投产阶段的水相运动规律进行研究,并深入分析含水率、油量、气量、油水相间摩擦系数等因素对水相运行的影响。结果表明:初始投产阶段水相在爬坡段分离和积聚,形成长时间的停滞,管道坡度越大,水相波动越剧烈;含水率越高的物流,水相在爬坡段聚集时间越短;气量增大则会降低水相滞液程度,提高水相运行速度,有助于水相爬坡;油量变化对水相运行速度的影响较小,油水相间摩擦系数对爬坡段水相运动有直接影响,油水相间摩擦系数修正拟合,对实际管道运行有重要指导意义。研究结果可为深水气田开发研究提供借鉴。

库区浮泥层纵向流速垂线分布特性研究

水库浮泥是存在于水库底部的一层高含沙水体,流动性较强,直接影响水库淤积形态和水库排沙,研究其运动规律对水库减淤优化调度具有重要意义。根据三峡库区实测泥沙矿物组成和级配资料,配置沙样进行流变试验,以幂律流变模型描述浮泥的本构关系。构建了浮泥运动的速度分布理论模型,通过水槽试验对模型进行了验证,计算结果与试验结果吻合较好。结果表明,浮泥运动速度随浮泥厚度、上层水流流速、床面坡度增大而增大,随浮泥密度增大而减少。沿水深方向浮泥纵向流速分布始终呈抛物线型,表层的浮泥流速要远大于底层浮泥,浮泥纵向流速沿垂向方向不断减少,最底部的浮泥几乎处于静止状态。

列车制动作用下悬索桥纵向运动及其黏滞阻尼器控制研究

列车的制动行为会对悬索桥的纵向运动产生影响,因此有必要对千米级大跨度铁路悬索桥在列车制动下的纵向运动进行研究。以一座主跨1060 m的大跨度铁路悬索桥为研究对象,采用数值模拟的方式探讨了列车制动作用下其梁端纵向运动的响应特性,并研究了黏滞阻尼器在控制纵向运动中的效果。首先介绍了该千米级大跨径铁路悬索桥的工程背景,以及基于ANSYS软件建立的有限元模型;然后介绍了大跨径铁路悬索桥纵向运动的加载求解方式,支座摩阻和黏滞阻尼器的有限元模拟方式,以及制动力的模拟方式;接着探究了不同制动位置、是否考虑支座摩阻力对悬索桥梁端纵向运动响应的影响;最后,研究了黏滞阻尼器的纵向运动控制效果,并进行了参数分析。研究结果表明:随着制动位置越接近下桥位置,纵向位移变化曲线形状越接近正弦函数形式;支座摩阻对列车制动作用下的梁端位移响应有一定的控制作用,对梁端速度响应控制效果不佳;采用黏滞阻尼器可以有效控制列车制动下的悬索桥梁端位移和速度响应;当采用阻尼系数为2500 kN(m/s)^(-α),阻尼指数为0.1的黏滞阻尼器时,控制效果最佳。

含水溶洞对采煤工作面覆岩移动的影响规律

含水溶洞的存在使得煤层覆岩移动规律具有特殊性。为了研究含水溶洞对煤层覆岩移动的影响,以贵州松南煤矿作为工程背景,利用FLAC 3D进行数值模拟研究,对比分析溶洞有无含水作用下煤层覆岩移动规律。研究发现:随着采煤工作面的推进,含水溶洞围岩裂隙和煤层顶板裂隙不断扩展,当工作面推进至与溶洞水平距离小于10 m时,溶洞围岩裂隙和顶板裂隙贯通,形成导水裂隙;含水溶洞煤层开采情况下,溶洞围岩变形下沉量相较于无水情况增加了37.24%,随着推进距离的增加,溶洞靠近采空区侧底角出现明显的下沉现象,溶洞右帮出现向内挤压现象,溶洞围岩和煤层顶板应力集中区和破坏区逐渐贯通;相比于无水情况,覆岩运移在含水条件下得到加强,其中最大曲率增大了0.88 mm/m^(2)、最大水平变形增大了1.81 mm/m。建议该矿采煤工作面与溶洞水平距离需大于10 m。

Application of jet main region specification model in CFD simulation for room air movement analysis

This paper analyzes the applications of four air terminal device（ATD）models（i.e.,the basic model,the box model,the N-point momentum model,the jet main region specification model）in computational fluid dynamics（CFD）simulation and their performance in case study.A full-scale experiment is performed in an environment chamber,and the measured air velocity and temperature fields are compared with the simulation results by using four ATD models.The velocity and temperature fields are measured by an omni-directional thermo-anemometer system.It demonstrates that the basic model and the box model are not applicable to complicated air terminal devices.At the occupant area,the relative errors between simulated and measured air velocities are less than 20% based on the N-point momentum model and the jet main region specification model.Around the ATD zone,the relative error between the numerical and measured air velocity based on the jet main region specification model is less than 15%.The jet main region specification model is proved to be an applicable approach and a more accurate way to study the airflow pattern around the ATD with complicated geometry.

血浆及脑脊液的神经丝轻链蛋白对帕金森病运动和认知功能障碍的研究进展

神经丝轻链蛋白(NfL)是细胞骨架的神经元特异性成分,其对于中枢神经和周围神经中树突分支和生长、轴突的稳定性以及创伤后轴突再生非常重要。轴突损伤导致NfL释放到细胞外间隙,因此,脑脊液(CSF)或血液NfL被认为是一系列神经系统疾病中轴突损伤和神经变性的生物标志物。帕金森病(PD)是一种慢性进展性疾病,发生严重运动与认知功能障碍PD患者的生活质量和临床结局更差。近年来的临床研究表明,NfL与PD的发生发展可能存在关联,但NfL与PD患者的运动和认知功能障碍的具体关系及其预后价值尚不完全明确,本文对此作一综述。

基于膜系理论的疾病治疗原则

膜系是全身膜状结构及其附属组织共同构成的多层次复杂系统,根据其是否与外界相通,可分为外通性膜系与内通性膜系。外通性膜系具有屏障保护功能,是与外界环境物质、信息和能量交换的重要结构;内通性膜系具有联络协调的功能,是机体各脏腑器官之间物质、信息和能量交换的重要结构。基于膜系理论,可指导临床膜系疾病的治疗。外通性膜系是重要的祛邪途径,临床可采用汗、吐、下等方法,通过调畅外通性膜系的气津输布,以祛邪而出。内通性膜系是疾病传变的重要途径,其常见病理为气机郁滞、水液代谢异常等,可通过调理膜系气津输布治疗疾病。调畅膜系气津输布时,应重点关注少阳与中焦气机,以恢复全身气机升降出入。全身膜系起源于肾,在膜系疾病早期注重顾护肾膜,可先安未受邪之地;在疾病中晚期调补肾阴肾阳,可治疾病之本,顾护正气。

Application of Computational Fluid Dynamics and Fluid Structure Interaction Techniques for Calculating the 3D Transient Flow of Journal Bearings Coupled with Rotor Systems

Journal bearings are important parts to keep the high dynamic performance of rotor machinery. Some methods have already been proposed to analysis the flow field of journal bearings, and in most of these methods simplified physical model and classic Reynolds equation are always applied. While the application of the general computational fluid dynamics （CFD）-fluid structure interaction （FSI） techniques is more beneficial for analysis of the fluid field in a journal bearing when more detailed solutions are needed. This paper deals with the quasi-coupling calculation of transient fluid dynamics of oil film in journal bearings and rotor dynamics with CFD-FSI techniques. The fluid dynamics of oil film is calculated by applying the so-called ＂dynamic mesh＂ technique. A new mesh movement approacb is presented while the dynamic mesh models provided by FLUENT are not suitable for the transient oil flow in journal bearings. The proposed mesh movement approach is based on the structured mesh. When the joumal moves, the movement distance of every grid in the flow field of bearing can be calculated, and then the update of the volume mesh can be handled automatically by user defined function （UDF）. The journal displacement at each time step is obtained by solving the moving equations of the rotor-bearing system under the known oil film force condition. A case study is carried out to calculate the locus of the journal center and pressure distribution of the journal in order to prove the feasibility of this method. The calculating results indicate that the proposed method can predict the transient flow field of a journal bearing in a rotor-bearing system where more realistic models are involved. The presented calculation method provides a basis for studying the nonlinear dynamic behavior of a general rotor-bearing system.

Focused fluid flow in the Baiyun Sag, northern South China Sea: implications for the source of gas in hydrate reservoirs

The origin and migration of natural gas and the accumulation of gas hydrates within the Pearl River Mouth Basin of the northern South China Sea are poorly understood. Based on high-resolution 2D/3D seismic data, three environments of focused fluid flow： gas chimneys, mud diapirs and active faults have been identified. Widespread gas chimneys that act as important conduits for fluid flow are located below bottom simulating reflections and above basal uplifts. The occurrence and evolution of gas chimneys can be divided into a violent eruptive stage and a quiet seepage stage. For most gas chimneys, the strong eruptions are deduced to have happened during the Dongsha Movement in the latest Miocene, which are observed below Pliocene strata and few active faults develop above the top of the Miocene. The formation pressures of the Baiyun Sag currently are considered to be normal, based on these terms： 1） Borehole pressure tests with pressure coefficients of 1.043-l.047; 2） The distribution of gas chimneys is limited to strata older than the Pliocene; 3） Disseminated methane hydrates, rather than fractured hydrates, are found in the hydrate samples; 4） The gas hydrate is mainly charged with biogenic gas rather than thermogenic gas based on the chemical tests from gas hydrates cores. However, periods of quiet focused fluid flow also enable the establishment of good conduits for the migration of abundant biogenic gas and lesser volumes ofthermogenic gas. A geological model goveming fluid flow has been proposed to interpret the release of overpressure, the migration of fluids and the formation of gas hydrates, in an integrated manner. This model suggests that gas chimneys positioned above basal uplifts were caused by the Dongsha Movement at about 5.5 Ma. Biogenic gas occupies the strata above the base of the middle Miocene and migrates slowly into the gas chimney columns. Some of the biogenic gas and small volumes ofthermogenic gas eventually contribute to the formation of the gas hydrates.

Simulation of Fluid Flow in a Channel Induced by Three Types of Fin-Like Motion

One of many interesting research activities in biofluidmechanics is dedicated to investigations of locomotion in water. Some of propulsion mechanisms observed in the underwater world are used in the development process of underwater autonomic vehicles （AUV）. In order to characterise several solutions according to their manoeuvrability, influence on the surrounding fluid and energetic efficiency, a detailed analysis of fin-like movement is indispensable. In the current paper an analysis of undulatory, oscillatory and combined fin-like movements by means of numerical simulation is carried out. The conservation equation of mass and the conservation equation of momentum axe solved with the Finite Volume Method （FWM） by use of the software CFX-10.0. The undulatory and oscillatory fin movements axe modelled with an equation that is implemented within an additional subroutine and joined with the main solver. N carried out in the computational domain, in which one fin is fixed in a flow-through water duct. Simulations axe carded out in the range of the Re number up to 105. The results show significant influence of applied fin motion on the velocity distribution in the surrounding fluid.

Crust-Mantle Structures and Gold Enrichment Mechanism of Mantle Fluid System

Gold enrichment mechanism of ore-forming fluid is the essenc e of gold metallization. This paper summarizes the distinguishing symbols of man tle fluid and effect of crust-mantle structure on fluid movement. Fluid moving processes include osmosis, surge, gas-liquid alternation and mutation of fluid speed. During fluid movement, gold will be enriched gradually. Finally, a layere d circulatory system is illustrated in this paper.

Rheological fluid motion in tube by metachronal waves of cilia

This paper presents a theoretical study of a non-linear rheological fluid transport in an axisymmetric tube by cilia. An attempt has been made to explain the role of cilia motion in the transport of fluid through the ductus efferent of the male reproductive tract. The Ostwald-de Waele power-law viscous fluid is considered to represent the rheological fluid. We analyze pumping by means of a sequence of cilia beats from rowto-row of cilia in a given row of cells and from one row of cells to the next(metachronal wave movement). For this purpose, we consider the conditions that the corresponding Reynolds number is small enough for inertial effects to be negligible, and the wavelengthto-diameter ratio is large enough so that the pressure can be considered uniform over the cross section. Analyses and computations of the fluid motion reveal that the time-average flow rate depends on ε, a non-dimensional measure involving the mean radius a of the tube and the cilia length. Thus, the flow rate significantly varies with the cilia length.Moreover, the flow rate has been reported to be close to the estimated value 6 × 10ml/h for human efferent ducts if ε is near 0.4. The estimated value was suggested by Lardner and Shack(Lardner, T. J. and Shack, W. J. Cilia transport. Bulletin of Mathematical Biology, 34, 325–335(1972)) for human based on the experimental observations of flow rates in efferent ducts of other animals, e.g., rat, ram, and bull. In addition, the nature of the rheological fluid, i.e., the value of the fluid index n strongly influences various flow-governed characteristics. An interesting feature of this paper is that the pumping improves the thickening behavior for small values of ε or in free pumping(?P = 0) and pumping(?P > 0) regions.

妊娠晚期胎死宫内的临床分析及风险预测

目的 分析妊娠晚期胎死宫内的危险因素及围产结局,构建并验证列线图风险预测模型。方法 选取妊娠晚期胎死宫内患者69例为病例组,另取同期正常分娩的孕妇69例为对照组。比较患者一般情况、母体因素、胎儿因素、胎儿附属物因素、围产结局等临床资料。采用Logistic回归分析妊娠晚期发生胎死宫内的危险因素,建立风险预测列线图模型,并使用Bootstrap法进行内部验证,计算C统计量(C-Statistic),Hosmer-Lemeshow检验评模型的拟合优度。结果病例组年龄高于对照组,产检次数少于对照组(P<0.05),非高等教育背景、非中心城区居住、无业、高龄(≥35岁)、经产妇、自觉胎动异常、子痫前期、双胎妊娠、宫内感染、胎儿系统超声异常、染色体异常、小于胎龄儿、脐带异常、羊水量异常、早产、经阴道分娩的比例均高于对照组(P<0.05)。Logistic回归分析显示,自觉胎动异常、子痫前期、双胎妊娠、胎儿系统超声或染色体异常、脐带或羊水量异常为发生妊娠晚期胎死宫内的独立危险因素,高产检次数为其保护因素(P<0.05)。基于多因素Logistic回归分析结果,结合临床实际情况将年龄同时纳入预测模型,建立列线图风险预测模型,Bootstrap内部验证和Hosmer-Lemeshow检验结果显示模型区分度(C-Statistic=0.937)和校准度良好(χ^(2)=5.364,P=0.643)。结论 构建的列线图模型可有效评估发生妊娠晚期胎死宫内的风险,具有良好的临床应用价值。

直丝弓口腔正畸矫治力与患者正畸牙移动、龈沟液炎症反应程度的相关性分析

目的探讨直丝弓口腔正畸矫治力与患者正畸牙移动、龈沟液炎症反应程度的相关性。方法前瞻性选取2017年1月至2022年12月在宿州市立医院行直丝弓口腔正畸的患儿100例,采用随机数字表法将患者分为A组、B组和C组,分别有33例、33例和34例,各组均给予直丝弓口腔正畸,A组、B组和C组分别施加0、100和150 g矫治力。观察两组的正畸牙移动距离、龈沟液炎症因子[白细胞介素(IL)-1β、肿瘤坏死因子-α(TNF-α)、IL-6]及牙周状况[菌斑指数(PLI)、牙龈指数(GI)和龈沟出血指数(SBI)]。结果正畸后1、2、3和4周,C组正畸牙移动距离明显高于A组和B组,B组正畸牙移动距离明显高于A组,差异均有统计学意义(P<0.05)。正畸前,A组、B组和C组龈沟液IL-1β、TNF-α、IL-6水平比较,差异均无统计学意义(P<0.05);正畸后1、3和7 d,C组龈沟液IL-1β、TNF-α、IL-6水平均明显高于B组和A组,B组龈沟液IL-1β、TNF-α、IL-6水平均明显高于A组,差异均有统计学意义(P<0.05)。A组、B组和C组正畸前后PLI、GI和龈沟SBI比较,差异均无统计学意义(P>0.05)。结论随着直丝弓口腔正畸矫治力的增加,正畸牙移动距离增加,龈沟液炎症因子水平升高,且随时间有所变化。

基于气一元论探讨过敏性鼻炎-哮喘综合征发病机制

气一元论认为,气是构成世界万物的本原,也是构成人体和维持生命活动的基本物质。人禀气而生、得气以长,肺主一身之气的生成和运行,鼻为肺之外窍,是天地之气与人体之气相互交换的重要场所。通过梳理气一元论学说,发现过敏性鼻炎-哮喘综合征的发病机制与气的物质和功能属性密切相关,提出天地之气未顺、人气失调,导致气机失衡、痰饮内停是过敏性鼻炎-哮喘综合征的重要病机。其中,天地之气未顺是发病外因,人气失调是发病根本且受天地之气影响,气机失衡、痰饮内停是发病的关键环节。

马济佩治疗中晚期糖尿病肾病水肿经验介绍

介绍马济佩教授辨证治疗中晚期糖尿病肾病水肿的临床经验。马济佩教授认为,本病为本虚标实之证,以脾肾阳虚为本,湿浊、血瘀、气滞为标。治疗上强调以补肾健脾,温阳利水为大法,兼顾化湿泄浊,活血化瘀和调畅气机。此外,配合中药熏洗方改善下肢循环,内外兼治,相得益彰。

三体船操纵性自航回转运动仿真预报分析

针对船舶操纵性自航回转试验成本较高,且现有成熟仿真方法效率低、分析要素单一等问题,本文提出了一种船舶自航回转运动数值模拟方法,并利用商用计算流体力学软件Star-CCM+对三体船模在满舵角30°和半舵角15°所受推力情况下的自航回转运动进行了数值模拟,将该模拟结果与较为成熟的基于数学模型方程组的约束模仿真回转运动结果进行了对比分析,通过对三体船在满舵角和半舵角时的纵距、横距、旋回初径和回转直径等操纵性回转要素值进行分析可知,其差值均在7%以内,验证了文中所提方法的可靠性。且采用文中所提方法对目标船模进行模拟计算时,不仅能够获得船模在平面运动内的回转性能要素,同时还能得到船模横摇、纵摇、升沉等多自由度运动响应要素,本文亦对三体船在满舵角和半舵角下做自航回转运动时的横摇、纵摇、升沉等响应要素进行了分析,从定性分析的角度看,模拟所得的各运动响应要素结果与实际船舶在做回转运动时产生的现象相符;从定量的角度分析,模拟目标船模所得各运动响应要素结果较好,不会对船模回转产生较大干扰。

从阳明而发之谵语防治探讨

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