查询词典 uniform velocity

The distributions of velocity, velocity gradient, shear stress, clongation stress, first normal stress difference and pressure of the flow of a power-law fluid in the profile die were analyzed. It indicates that for a power-law fluid only after a few iterations a good convergence can be reached, even though in the case of high extrusion velocity.

本文分析了幂律流体在异型材挤出口模内的速度分布、速度梯度分布、剪切应力分布、拉伸应力分布、第一法向应力差分布和压力场，研究表明采用幂律流体模型，即使在挤出速度非常大的情况下，经过有限次迭代，模拟计算都能够收敛，并得到合理的结果。

In this dissertation the"Penalty"finite element method was employed to compute the velocity of the three-dimensional flow of power-law fluid in a profile die. In order to decrease the needed computer memory and raise the stability of numerical simulation, a set of decoupled methods such as PFEM, pseudo-body force method and transformation of momentum equation to the elliptic equation was developed to establish the general finite element equations to compute the distributions of velocity and viscoelastic stress of the three-dimensional viscoelastic flow of the Phan ThienTanner fluid in a profile die. During numerical simulation of the extrudate swell of the PTT fluid, the flow in the die and out of the die was analyzed separately, which demands less computer memory. The key techniques used in numerical simulation of the three-dimensional extrusion from dies such as decision of boundary conditions, creation of initial velocity field, selection of penalty factor, high Weissenberg number problem , regeneration of the free surface were studied in detail.

中文题名聚合物异型材口模挤出三维流动研究副题名外文题名 Study on three-dimensional flow of polymer melts during the process of profile extrusion from dies 论文作者涂志刚导师柳和生包忠诩教授学科专业材料加工工程研究领域\研究方向学位级别博士学位授予单位南昌大学学位授予日期2001 论文页码总数148页关键词挤出成型聚合物材料挤出口模聚合物异型材馆藏号BSLW /2003 /TQ320 /9 本文建立了求解挤出口模内幂律流体流动速度场的通用三维罚有限元模型；对于非线性粘弹性的Phan Thien-Tanner流体，为了降低模拟计算对计算机硬件的要求，并使模拟计算更加稳定，采用了一种去耦算法，包括罚有限元方法、拟体力方法和动量方程的椭圆类方程转化方法，并建立了求解速度场和粘弹性应力场的总体有限元方程；对于PTT流体的挤出胀大问题，提出了挤出胀大熔体口模内外分离模拟法，这样可以显著降低数值模拟对计算机硬件的要求。

Compared with the sail style and the hang style, the hitch kick style have advantages to join the front swing and trig swing of swing leg tightly, to speed the buffer and stretch of take-o?leg, to acquire more vertical muzzle velocity and to decrease losing of horizontal velocity, which results in more velocity and more angle when take o?.and more vertical height of body center, has advantage to obtain better result.

走步式空中技术能在起跳过程中通过紧密衔接的摆动腿加速前摆和制动前摆，加快起跳腿的缓冲和蹬伸动作速度，促进身体重心获得更大的垂直速度，而且水平速度没有更多的损耗，从而获得更大的腾起速度和腾起角，腾起时身体重心的垂直位置更高，最终取得优异成绩，促进跳远起跳技术朝着快速积极的方向发展。

As the study shows, the signal of recoil velocity is selected by the velocity sensor, then the electric current of magnetic liquid buffer is confirmed through the contrast and calculation of the control system, and the movement resistance is adjusted by changing the viscosity of magnetic liquid medium, so the velocity fluctuation of bolt is reduced effectively.

研究结果表明，通过枪管速度传感器，采集发射时的后坐速度信号，经控制系统的对比和解算，确定磁流体缓冲装置的励磁电流，改变磁流体介质的动力粘度，调节自动机运动阻力，可以有效地减小自动机前冲击发速度的波动。

This paper reviewed the theory, development and applications of 3 typical velocity analysis technologies, stack velocity analysis, migration velocity analysis and tomographic inversion.

主要对叠加速度分析，偏移速度分析和速度层析反演三大类典型的速度分析方法的基本原理，发展及应用条件等作简要的回顾与介绍。

The conclusion is that the extent of the zenith blind zone was restricted by three parameters: maximum azimuth angular velocity of tracking mount, flight level and airspeed of the target. In astronomical coordinates (reference mark is north latitude 43. 9°), analyzed is the effect of azimuth angular velocity, acceleration and altitude angular velocity, acceleration etc. Some formulae were given to compute all correlative quantities.

在观测坐标系中推导出确定天顶盲区理论范围公式和满足过天顶跟踪条件的关系式；在天文坐标系中以长春卫星观测站（北纬43.9°）作为计算基准，分别讨论了方位、俯仰方向的角速度、角加速度等对天顶盲区的影响，在理论分析上为解决过天顶跟踪问题打下了基础。

The conclusion is that the extent of the zenith blind zone was restricted by three parameters: maximum azimuth angular velocity of tracking mount, flight level and airspeed of the target. In astronomical coordinates (reference mark is north latitude 43.9 ), analyzed is the effect of azimuth angular velocity, acceleration and altitude angular velocity, acceleration etc. Some formulae were given to compute all correlative quantities.

在观测坐标系中推导出确定天顶盲区理论范围公式和满足过天项跟踪条件的关系式；在天文坐标系中以长春卫星观测站(北纬43.9°)作为计算基准，分别讨论了方位、俯仰方向的角速度、角加速度等对天顶盲区的影响，在理论分析上为解决过天顶跟踪问题打下了基础。

The computationresults show that for a organ-pipe nozzle with a given configuration size, the nondimensional axial velocity attenuates slower with the increase in stand-distance, and the nondimensional axial velocity attenuation pattern remains the same, and the nondimensional axial velocity along the jet centerline attenuates slower with the increase in distance between the nozzleexit and the impinging plate.

计算结果还表明：对给定结构尺寸的风琴管喷嘴，随着喷距的增加，沿径向的无因次轴向速度衰减变慢、沿径向无因次轴向速度衰减规律不随喷速的变化而变化；无因次轴心速度的衰减规律随着喷嘴出口到井底间距离的增大，射流轴心速度衰减变慢，但其变化幅度不大；在固定靶距情况下，无因次轴心速度衰减规律不随喷速的变化而变化。

Methods Patients were divided into different groups, then all patients underwent renal color Doppler energy imaging examinations. The changes of systolic peak velocity, diastolic peak velocity, mean glow velocity, pulsatility index and resistent index of renal blood flow were observed.

将病人分组后，应用彩色多普勒超声仪进行肾脏的彩色多普勒能量图的扫描；并观测肾血流收缩期峰值流速，舒张末期峰值流速，平均流速，搏动指数及阻力指数的变化。

3D effect is analyzed and the average velocity of wave propagating in the pile, which mainly influences inverse interpretation, is discussed. Finally, the theory results are verified by model experiment. It is shown that 3D results have the same phase with ID results. The pile radius, the duration of impulse, the ratio of hammer radius to pile radius and shear velocity of the soil around the pile have influences on 3D effect. The best position of receiver is 0.55R from the pile center. The average velocity of wave propagating in the pile reduces due to transversal inertia effect and 3D effect.

结果表明：三维曲线与一维结果在相位特征上一致；波场图直观地反映了波在桩中的传播规律；三维效应与桩径、激振脉冲宽度、相对激振半径及桩周土剪切波速有关；传感器放在0.55R处可以得到干扰较小的信号；三维效应和横向惯性效应的存在会使桩中的波速减小，土的性质对波速影响不大；反演精度与缺陷的性质、激振条件有关。

The dissecting of samples in group2 were difficult. The root of pulmonary artery and ascending aorta failed to be unfolded because fibrous tissue was tough, right and left fibrous trigone were too firm to be solved by hand. Cardiac muscle fibers couldn't be stripped along myofibrillar trajectory since they were prone to break because of their friability.

组2的心脏解剖困难，表现为纤维组织坚韧，游离肺动脉非常困难；徒手无法松解左、右纤维三角，肺动脉和主动脉根部的游离非常困难；心肌纤维坚硬、质脆，解剖时容易断离成碎块，无法沿纤维走行方向剥离。

We have battled against the odds in a province that has become increasingly violent.

我们对在一个争夺日益激烈省的可能性。