查询词典 high velocity

SiC is a very promising material for high temperature, high power, high frequency, and radiation application because of its superior properties such as wide band gap, high critical breakdown field, high thermal conductivity and high saturation electron drift velocity.

SiC材料具有宽禁带、高临界击穿电场、高热导率、高载流子饱和漂移速度等优良特性，这些特性决定了它在高温、大功率、高频和抗辐照等方面的有着广泛的应用前景。

High-frequency and high power electronic or microwave devices, because of their excellent properties such as wide band gap, high electron saturation drift velocity, low dielectric constant, high thermal conductivity, good chemical and thermal stability, and so on.

同时由于GaN基材料具有电子漂移饱和速度高、介电常数小、导热性能好、化学和热稳定性好等特点，也非常适合于制作高温、高频及大功率电子器件。

Those problems include inverse position analysis of the machine, inverse and direct position analysis of the parallel locking mechanism, relationships of velocity and acceleration between cutter and actuators, Jacobian matrix of the machine, forward position computation of the machine, the links'velocity and acceleration of the driving chains, the links'velocity and acceleration of the locking mechanism, kinematics simulation of the machine, and so on. The Jacobian method presented in the thesis to calculate the direct position of the machine is of high efficient.

其中包括机床的位置逆解分析，平行机构的位置逆解分析，机床刀具与各主动关节之间的速度和加速度映射关系的求解，并联机床雅可比矩阵的计算，并联机床的位置正解计算，支链构件的速度和加速度计算，平行机构各构件的速度和加速度计算以及机床各运动学指标的仿真计算等。

By a series field observation data, an empirical equation of mean velocity of viscous debris flow was got. The velocity calculated by the asymmetric coefficients, bottom slope and hydraulic radius of flow. It is good at both high resistance and low resistance area of debris flows. It is good consistent for the measuring velocity of otherwise field observation data of debris flow and viscous mudflow by this empirical equation.

由一系列野外观测资料得到的由泥石流不均匀系数、泥石流运动底部纵比降和水力半径计算的粘性泥石流运动平均速度经验公式，能适应各种类型的泥石流沟，与其它系列的观测资料对比有很好的一致性，与粘性泥流的观测资料对比也很接近。

The main research content is: Using the experimental of cutting force and roughness of high speed face milling cutter and high speed end milling cutter mill aluminium alloy and cast iron, analyze the rules of the high speed milling velocity, feed rate per tooth, milling depth and milling width to high speed processing. Use multiple linear regression method, set up surface roughness and the cutting force fluctuation models. Certify the regression model notability, and provide a reliable guarantee for the accuracy of function optimization. Based on the targets of productivity, manufacturing cost, surface roughness, cutting force fluctuation optimization model, according to research of the high speed milling parameters selecting restrict of work piece, machine, tool and safety, set up high speed milling parameters multi-object optimization system.

本文以已有的高速铣削机理及高速刀具技术研究成果为基础，结合高速铣削试验，进行了基于遗传算法的高速铣削参数优化研究与系统开发，主要的研究内容为：通过高速面铣刀和高速立铣刀加工铝合金和铸铁等材料的切削力和表面粗糙度试验，进行了铣削速度、每齿进给量、铣削深度和铣削宽度对高速铣削加工过程影响的研究；采用多元线形回归的方法，建立了切削力及其振幅和表面粗糙度模型，并对模型的显著性进行验证，为高速铣削参数优化模型的建立奠定了基础。

Aiming at these problems, we have designed the processing workflow to effectively suppress the surface Wave interference, regular interference, high energy interference, and other random noise interference. The treatment clue was from thick to thin. Firstly, the spectral analysis method was used to establish macroscopic velocity field. Then, the ray tomography method was used to enhance the accuracy of velocity analysis and to establish a more accurate velocity model. Finally, the finite difference pre-stack depth migration on method in -k domain was adopted to solve the imaging problem of subsalt and salt dome flank.

通过合理组织处理流程，有效压制了面波干扰、规则于扰、强能量干扰和随机噪声干扰；采用由粗到细的思路，先利用谱分析方法建立宏现速度场，再利用射线层析成像方法提高速度分析精度，建立了较为准确的速度模型；利用频率－空间域有限差分叠前深度偏移解决了盐下及盐丘侧翼的成像问题。

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。

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。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。