查询词典 acoustic velocity

In applying high concentration burning technique to improving burning efficiency for pulverized coal burner, for studying the effect of solid flows of different concentration on burning, Euler mathematical model is set up using gas-solid two phase flow theory. The paper describes the low concentration pulverized coal in horizontal primary air pipe. The relationship between the velocity and concentration of gas phase and that of solid phase, and the effect of gas flow velocity on gas-solid two-phase flows, is arrived through calculating the flow field. Reasonable gas flow velocity is proposed.

在应用高浓度燃烧技术提高煤粉炉的燃烧效率时，为了研究不同浓度固相流动对燃烧的影响，应用气固两相流理论建立Euler数学模型对一次风水平管道中低浓度的煤粉颗粒进行了描述，通过求解流场，得到了管内气相和固相的速度和浓度的分布关系，及其气体流速对气固两相流动的影响，并提出合理气流速度。

Prominence a wide variety of shapes and movement characteristics, in general can be divided into four categories:(1) quiet prominence, change is slow, longer life expectancy, up to the number, and with the presence of sunspots related to sunspots for a long time, it is also a little more;(2) the activities of prominence, from a quiet prominence changes years, the movement is faster, but lower than the sun's surface escape velocity, so mostly circular, the material eventually thrown off the plane back to Japan;(3) the outbreak of prominence, activities of the most intense one, and sometimes velocity can exceed the Sun the surface escape velocity, reaching 100 km D seconds, or even higher altitudes of up to one million kilometers, 20,000 kilometers thick;(4) crown-shaped prominence, looks like clouds, is a rather exceptional prominence.

日珥有各种各样的形状和运动特征，大体上可分为四类：（1）宁静日珥，变化缓慢，寿命较长，可达数目，并与黑子的存在有关，黑子多时，它也多一些；（2）活动日珥，由宁静日珥变化而来，运动速度较快，但低于太阳表面逃逸速度，因此多为环形，抛出的物质最终仍落回日面；（3）爆发日珥，活动最激烈的一种，有时运动速度可超过太阳表面逃逸速度，达100公里D秒，甚至更高，高度可达上百万公里，厚达2万公里；（4）冕形日珥，貌似浮云，是一种比较特殊的日珥。

The wave velocity ratio vertical to the stratum of the rock samples is usually less than that in parallel direction, and the relative increment of wave velocity ratio between the vertical direction and the parallel direction decreases as the wave velocity ratio in vertical direction gradually increases.

波速比的各向异性特征主要表现为垂直层理方向上的波速比普遍小于平行层理方向，且两方向波速比的相对增量还随着垂直层理方向上的波速比的增大而逐步减小。

In order to contribute to analyse and compute easily setback moving devices on the projectile fuzes,and to make the fuze devisers be able to get the approximate acceleration curves with a few parameters such as tube length and muzzle velocity of the guns,the displacement-time curve and velocity-time curve of gun interior ballistic are fitted with the Logistic models,then the formula of projectile acceleration curves in bore are gotten by the derivation of the formula of fitting velocity-time curve.

为了便于炮弹引信后坐运动机构的分析和计算，能使引信工作者只根据身管长度和炮口速度等少量参数就能获得弹丸膛内加速度近似曲线，运用Logistic函数拟合火炮内弹道的位移－时间曲线和速度－时间曲线，再对拟合得到的速度－时间曲线求导便得到了弹丸膛内加速度近似曲线。

The study area is basically located in hydrodynamic balance belt, and the suspended sediment transport is characteristics of reciprocating movement and small amount of net sediment discharge. The net suspended sediment transport is mainly controlled by average current transport, Stokes drift-induced transport and gravitational circulation transport. The advection transport effect gradually weakens and gravitational circulation transport evidently intensifies from Hangzhou Bay to the offshore area. Settling velocity of single particles is far smaller than that of floccules, so, influence of flocculation of suspended sediments must be taken into the consideration.Incipient velocity and transport flux of surface sediments are analyzed using formulas of incipient velocity and transport flux. Transport trend and controlling factors of surface sediments are studied by the method of grain size trend analysis.

结果表明，研究区净悬沙通量自杭州湾内向外海迅速变小，悬沙总体由杭州湾向外海输运，但同时存在向杭州湾方向的净输沙；研究区基本处于水动力平衡带，悬沙输运具有往复搬运、净输沙量小的特点；平均流输运、Stokes漂移输运和垂向净环流输运是引起悬沙泥沙净输运的主要作用机制，自口门至外海，平流输运作用逐渐减弱，垂向净环流输沙在悬沙净输运中所占比例逐渐增加；舟山群岛海域既是杭州湾向东海输运泥沙的重要通道，也是东海沿岸流携带泥沙向南输运的过渡地带；研究区单颗粒泥沙沉降速度很小，远小于絮凝沉降速度，在研究本区悬沙沉降时必须考虑絮凝的影响。

PDA laser flow velocity testing technique was used to measure the flow velocity of solid particles in the solid-liquid-gas three-phase system in a flotation cell and obtained the velocity distribution of solid particles so as to provide reliable data for the study on adsorption and deadsoption mechanism of particles onto and off from bubbles.

采用PDA激光流速测试技术，在固-液-气三相体系中对浮选槽中固体颗粒进行了流速测定，获得了固体颗粒的速度分布，为矿粒与气泡粘附过程和脱附过程机理的研究提供可靠数据。

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.

详细分析了聚合物口模挤出三维计算机模拟研究中的若干关键技术问题，如对异型材结构特点的分析、边界条件的确定、初始速度场的自动生成、罚数的求取、粘弹性流动模拟中的高We数问题、三维挤出胀大的自由界面更新等。

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。

Finally it offers the analysis of the fault-tolerance system as well as its test verification.

这样，运行于空间环境中的系统的设计目标就是在保证系统实时性

However, it is still difficult to find out the real reason of the increase of the keratinized gingiva during the orthodontic extrusion whether it is due to the proliferation of the gingival tissue or to its elastic nature, that is because the proliferation of the fibroblasts as well as the connective tissue changes in volume and the intra-fibers spaces were all immeasurable in most of the studies.

然而，仍然难以找到真正的原因增加的角化牙龈在正畸挤压它是否是由于扩散的牙龈组织或其弹性性质，这是因为增殖的成纤维细胞以及作为结缔组织的变化量和内部纤维空格都是不可估量的，大多数的研究。