Two-Dimensional Wave Motion on the Charged Surface of a Viscous Liquid
超声剪切波弹性成像的技术进展
超声剪切波弹性成像的技术进展李强【摘要】E成像,又称为实时剪切波弹性成像,该技术是近来兴起的一种实时二维弹性成像技术,它与静态弹性成像技术有本质的区别,与瞬时弹性成像技术以及声辐射力弹性成像技术相比,在技术上也有了新的进展.本文介绍了弹性成像的相关原理,以及现阶段应用于临床的弹性成像技术,并着重探讨了实现E成像快速、实时、大范围检测的技术方法,尤其是在剪切波产生、检测、成像方面采用的技术,如"马赫圆锥"动态的相干增强技术,一次并行发射、接收的超高频成像技术.同时对E成像技术的研究及其临床应用进展做了综述,最后对剪切波弹性成像技术的未来应用进行了展望.%E imaging, also named shear wave elastography (SWE) is a real time elastography technology of two-dimensional emerging in recent years. It is not only fundamentally different from the static elastography technique, but also different from transient elastography and acoustic radiation force impulse. A new technology progress has occurred in SWE. In this paper, the related principle of elastography and several elastography technologies in clinical application were introduced, and the methods of achieving rapid, real-time, and extensive testing of SWE were explored. Meanwhile, emerging and detecting methods of SWE, for example, dynamic coherence enhancement technique based on "March Wave" and ultra high frequency imaging technology for one transmitting-receiving were renumbered. Moreover, this paper reviewed the technology researches and clinical applications of SWE, and the future development of SWE was discussed in the end.【期刊名称】《中国医疗设备》【年(卷),期】2017(032)007【总页数】6页(P101-105,123)【关键词】E成像;声辐射力脉冲;马赫圆锥;超高频;杨氏模量;声束形成【作者】李强【作者单位】泰安市中医医院设备科,山东泰安271000【正文语种】中文【中图分类】R445.1超声诊断技术的发展，包括A型（Amplitude）、B型（Brightness）、M型（Motion）、C型（Color）、D型（Doppler）超声等，经历了一个由“点”（A型超声）、“线”(M型超声）、“面”（二维超声）、“体”（三维超声）的发展过程[1]。
Simplifiedwavemodelling
Simplified wave modellingJohn C. BancroftABSTRACTWave motion is modelled using the acoustic wave equation and implemented using MATLAB. This method requires two initial conditions that are introduced using a simple wavelet on a one dimensional propagator such as a string, spring, or wire. This model is expanded to two dimensions that illustrate plane-wave propagation, boundary effects, and Huygen’s wavelets.WAVE ON A STRING.Assume we want to model transverse wave motion on a string (spring, wire, etc). We will compute the motion of a wavelet at equal time increments that simulate photos to evaluate the motion.We start with a Gaussian-shaped wavelet illustrated below in Figure 1 that represents a photograph of the transverse displacement. We have chosen the width of the wavelet to be large, relative to the sample interval so that linear interpolation provides an adequate description, i.e. the sample rate is approximately ten times the maximum frequency to minimize grid dispersion. Given this information:•What is the direction of motion?•What will be the shape in the next photograph?FIG 1: A representation of a Gaussian shaped wavelet on a string.Is the wavelet in Figure 1 going to move to the left, the right or bounce up and down? We simply don’t know because we don’t have enough information. How do we provide that additional information? Let’s examine the wave equation to find out.The string has one distance dimension, x, and we define the displacement p(x), at different time intervals such as p(x, t=1), p(x, t=2), etc. It therefore becomes convenient to define a 2D array, p(x, t), that defines the amplitude of the strings displacement at agiven location, x , and time, t . The movement of energy on the string is governed by the one dimensional acoustic wave-equation()()22222,,1p x t p x t x v t∂∂=∂∂. (1) We will use the finite difference method to approximate the wave-equation. A second derivative of a function, f(x), is approximated in a discrete form of f at position, n , i.e. f n , and is approximated by()211222n n n f x f f f x x δ−+∂−+=∂, (2) where the increments of f n are d x . The finite difference equation for the wave equation becomes: 1,,1,,1,,1222221i j i j i j i j i j i j p p p p p p x v tδδ−+−+−+−+=. (3) This equation can be represented in graphical form in the following figure, with the increment, i , representing distance to the left, and j , the time increment that increases vertically.FIG 2: Finite difference model of full wave-equation.We wish to compute the position of the string at a new time, given some initial condition. We will choose p i, j+1 as the unknown value in the finite-difference equation because it is a single value at a new time, giving()22,1,,11,,1,222i j i j i j i j i j i j v t p p p p p p x δδ+−−+=−−+. (4) According to this equation, we need to know the position of the string at the two previous times, j , and j-1; .i.e. the two initial conditions of the string. Shown below is thefinite-difference operator positioned at the at i th spatial location to calculate the amplitude on the string for the third time, at j=3.i-1 i+1iFIG 3: The first two initial conditions at j =1 and 2 to compute the first line of samples at j=3. If we desire to model a wave travelling down the string, then we need to start with a wavelet on the string at time j=1, and the same wavelet repeated on the string at time j=2 but moved to a new spatial location. The location on the j=2 string is critical and must have a spatial increment defined by the wave velocity, v , and the time increment, d t . These two initial conditions would also match any two sequential photos of the wave moving down the string. They are shown above, along with the finite-difference operator, illustrating the computation of the amplitudes on the string at time, j=3. (The above figure has used a very large d x on the operator for the purposes of illustration only).Computer simulations are illustrated in Figure 4, with (a) showing the amplitude of a Gaussian wavelet on the string at the first two times and the resulting calculation of the wavelet at the third time, k=3. The amplitudes at succeeding times may be calculated from the previous two times as illustrated in (b) that shows the wavelet at a time increment, k=50. The initial two wavelets are also shown to demonstrate how well the amplitude and shape of the wavelet has been preserved after 48 iterations.The complete MATLAB code for producing Figures 4 and 5 is listed in Appendix A. The part of the code that propagates the wavefield is six lines that are encircled to illustrate the simplicity. The coding method is similar to FORTRAN and does not take advantage of vector math that is available to a programmer.a)b)FIG 4: The first two initial conditions and the computation of a) the next third time increment, and b) at 50 time increments later. Note the preservation of the shape and amplitude.The full set of iterations are shown below in a three-dimensional view that shows the amplitude of the wavelet at the incremental times. This is a trivial task in MATLAB that simply displays 2D array, p(t, x), in Figure 5 with the call, “figure (3); mesh(p);”, highlighted in the program listing in appendix A. This figure has zoom androtation features that allow the programmer to view the image from any position. Thesimple coding of this program, along with the powerful MATLAB graphics, provide anexcellent analysis tool.FIG 5: A full set of time images of the displacementTo illustrate the importance of the initial conditions, various configurations of the first two wavelets are shown in the following figures. Note the effect on the subsequent propagations.•Figure 6a and b show the first two wavelets at the same amplitude and location at the centre of the string. The result is two wavelets moving away from eachother. (These two images demonstrate two different perspective views of thesame figure).•Figure 6c shows the two initiating wavelets at the same location, but the second is twice the amplitude, producing an interesting deformation of thestring. A similar type of deformation is obtained by zeroing the amplitude ofthe second wavelet as viewed in Figure 6d.We refer to the setting of the two initial conditions or the defining the deformation ofthe string at the first two time intervals as “exciting” the string.a) b)c) d) FIG 6: Various wave propagations that result when the initial conditions are varied, a) when the location and amplitude are the same, b) the same as (a) but a different view, c) with the same location but the amplitude of the second initial condition has twice the amplitude, and d) when the second initial condition is zero.2D WAVE PROPAGATIONThe propagation of energy on a 2D plane is also quite simple to program by extending the concepts of the 1D program. The two-dimensional wave equation,()()()2222222,,,,,,1p x z t p x z t p x z t x z v t∂∂∂+=∂∂∂, (5) becomes the finite difference equation, 1,,,,1,,,1,,,,1,,,1,,,,122222221i j k i j k i j k i j k i j k i j k i j k i j k i j k p p p p p p p p p x z v t δδδ−+−+−+−+−+−++=. (6) Solving for the single time sample at k+1 we get:1,,,,1,,,1,,,,1,22,,1,,,,122222i j k i j k i j k i j k i j k i j k i j k i j k i j k p p p p p p p p p v t x z δδδ−+−++−−+−+ =−++. (7) This difference equation is illustrated in Figure 7. A plane through the central points represents time at the k th level and the one sample point below this plane is a sample on the previous time layer at k-1. The single point to be computed (the circle) lies on the upper plane at time k+1.FIG 7: Schematic representation of the three-dimensional (x, z, t ) operator.We therefore need two planes of the wavefield (at k-1, and k ) to start the propagation. As in the 1D case, it is critical that the first two planes represent the desired initial conditions. In Figure 8a below, the initial wavefield starts at the centre of the plane and then, after 80 time iteration of computing the wavefield, we get the wavefield shifted to the left as evident in part (b). Note that the amplitude and shape of the wave field has been preserved.a) b) FIG 8: A plane wave designed to propagate to the left, a) at time zero, and b) at after 80 time increments.Figure 9a show the an initialization of a plane-wave that only extend part way across the surface. The resulting wavefield after 80 time iterations is shown in various perspectiveviews in panels b), c), and d). Note the unusual effect of this result as energy has propagated opposite to the direction to the main part of the wavefront.a) b)c) d)FIG 9: A portion of a plane-wave is propagated 40 time increments with: a) the initial location with a rounded edge, b) a perspective view after 40 time lags, c) side view, and d) a plan view.Figure 10 contains two images that result from a 3-D Gaussian-shaped wavelet that is circular in (x, z) as displayed in Figure 11a. The circular wavefront in part (a) in Figure 10 was excited by keeping the two excitation wavelets at the same location, while part (b) was excited by moving the second wavelet to the left with the propagation velocity. Note that even though the wavelet was initially propagated to the left, some energy also moves in the opposite direction.Figure 11 displays three additional wavelets in (b), (c), and (d) that are truncated to widths of five, three, and one sample. The intent of these wavelets is to represent some form of decomposition of a plane wave: i.e. part (d) is just one slice from the wavefront. This slice is definitely aliased in the direction parallel to the wavefront and we should expect some form of dispersion during propagation.Each wavelet is propagated in the direction of the wavefront and creates the circular images on the left side of the corresponding parts of Figure 12. These circular imagesrepresent some form of Huygen’s wavelets that are used to propagate wavefronts. The right side of these figures are the wavefront that are reconstructed from the Huygen’s wavelets. This was achieved by assuming source points were positioned at the original location of the wavefront (i.e. a continuous line of samples) and the resulting Huygen’s wavelets summed.a) b) FIG 10: Two wavefront responses from a Gaussian shaped wavelet at the centre with different initial conditions; with a) the initial wavelets at the same location, and b) when the second initial wavelet is shifted to the left with the medium’s velocity.a) b) c) d) FIG 11: Wavelet sources with a) the full circular wavelet, b) truncated to five points wide, c) three points wide and d) one point wide.a)b)c)d)FIG 12: Huygen’s wavefronts on the left side of each image when the source wavelet is: a) circular; b) 5 points wide; c) 3 points wide; and d) 1 sample wide. The right side is the corresponding reconstruction of the wavefront from an array of source points.FIG 13: Reconstructed wavefront and Huygen’s wavelet approximation when a single sample spike is propagated as part of a wavefront.The results of using a single sample for excitation is illustrated in Figure 13. Aliasing in the direction of wavefield propagation causes excessive dispersion of the energy.The non-aliased circular/Gaussian wavelet of Figure 11a was used to demonstrate the formation of the Huygen’s wavelet. This is illustrated in Figure 14, which shows the propagating wavefields at time intervals of 5, 10, 20, 30, 40, 50, 60, and 80. Note the formation of the phase-shift as the amplitudes become negative, and that some energy is propagated in the reverse direction.The Huygen’s wavelet energy lies on a circular path that extends in all directions around the excitation point. The amplitude tapers to zero in the direction opposite the excitation direction, and then to a maximum in the direction of excitation or propagation. Figure 15 is a side view of the Huygen’s wavelet that shows the peak amplitude has a linear slope that rises in the direction of propagation. This amplitude is described in theory as 1+cosine(q), where q is the angle from the direction of propagation. Also note that the phase-shift appears to be 45 degrees.COMMENTSThe images in Figure 10 illustrate the difference in the energy radiated from an isotropic point source and that of an element on a wavefront.The small portion of MATLAB code that propagates the 2D energy is included asAppendix B.FIG 14: Formation of a Huygen’s wavelet at 5,10, 20, 30, 40, 50, 60, 80 time units.FIG 15: Side view of Huygen’s wavelet displaying the amplitude.CONCLUSIONSWave propagation can be illustrated using simple programs written and displayed in MATLAB.ACKNOWLEDGEMENTSWe acknowledge NSERC and the CREWES sponsors for their continued support.APPENDIX AMATLAB code for modelling 2D data. The two parts encircled contain the wave propagation code and the function call to plot the view of the full movement of the waveform.% Wave on stringclearv = 1000.0; % Velocitydx = 1.0; % x incrementdt = 0.001; % time incrementnx = 100; %Number of x samplesnt = 100; %Number of z samplesp = zeros(nt,nx); % Matrix for strings1 = zeros(nx); % String at time 1s2 = zeros(nx); % String at time 2s40= zeros(nx); % String at time 50xary=zeros(nx); % Plot axis% Define the position of the string at the first two times for ix = -10:10p(1, ix+20 ) = 100*exp(-(ix^2 )/16.0 );p(2, ix+21 ) = 100*exp(-(ix^2 )/16.0 );end% Loop for each time increment: limit time to prevent distortion due to boundary reflectionfor it = 3: nt-55for ix = 2:99p(it,ix) = 2*p(it-1,ix) - p( it-2, ix) +((v*dt/dx)^2)*(p(it-1,ix-1)-2*p(it-1,ix)+p(it-1,ix+1)); endend% Get singel copies of the two excitation arrays and one latter array.for ix = 1:nxxary(ix)=ix;s1(ix) = p(1, ix);s2(ix) = p(2, ix);s40(ix) = p(40, ix);end% Plot the datafigure (1); plot(xary,s2,'r--',xary,s1,'b','LineWidth',3); xlabel('x','FontSize',20), ylabel('Amp','FontSize',20)title(' \it{ Wave on string}', 'FontSize',20)figure (2); plot(xary,s40,'g:',xary,s2,'r--',xary,s1,'b','LineWidth',3);xlabel('x','FontSize',20), ylabel('Amp','FontSize',20)title(' \it{ Wave on string}', 'FontSize',20)figure(3); mesh( p);xlabel('x','FontSize',20), ylabel('t','FontSize',20),zlabel('Amp','FontSize',20)title(' \it{ Wave on string}', 'FontSize',20)a) b)c)FIG A1: MATLAB windows with results of the 1D modelling code showing: a) the initial conditions on a string; b) initial conditions on a string and the wave after 40 time increments; and c) all 40 time increments on the string.APPENDIX BPortion of MATLAB code for modelling 3D data that propagates the wave.%********************************************************* % Compute each time layerfor it = 3:ntdit% Compute each x tracefor ix = 2:nx-1%Compute each sample in tracefor iz = 2:nz-1p = vol(ix, iz, it-1);ptm1 = vol(ix, iz, it-2);pzm1 = vol(ix, iz-1, it-1);pzp1 = vol(ix, iz+1, it-1);pxm1 = vol(ix-1, iz, it-1);pxp1 = vol(ix+1, iz, it-1);%solve wave-equationptp1 = 2.0*p - ptm1 + V^2*dt^2*( (pxm1 -2*p+pxp1)/dx^2 + (pzm1 -2*p + pzp1)/dz^2 );vol(ix, iz, it) = vol(ix, iz, it) + ptp1;endend%********************************************************。
流体力学中英文术语
流体力学中英文术语Index 翻译（Fluid Mechanics）Absolute pressure,绝对压力（压强）Absolute temperature scales, 绝对温标Absolute viscosity, 绝对粘度Acceleration加速度centripetal, 向心的convective, 对流的Coriolis, 科氏的field of a fluid, 流场force and，作用力与……local, 局部的Uniform linear, 均一线性的Acceleration field加速度场Ackeret theory, 阿克莱特定理Active flow control, 主动流动控制Actuator disk, 促动盘Added mass, 附加质量Adiabatic flow绝热流with friction,考虑摩擦的isentropic,等熵的air, 气体with area changes, 伴有空间转换Bemoullii’s equation and, 伯努利方程Mach number relations,马赫数关系式，pressure and density relations, 压力-速度关系式sonic point，critical values, 音速点，临界值，stagnation enthalpy, 滞止焓Adiabatic processes, 绝热过程Adiabatic relations, 绝热关系Adverse pressure gradient, 逆压力梯度Aerodynamic forces, on road vehicles, 交通工具,空气动力Aerodynamics, 空气动力学Aeronautics, new trends in, 航空学，新趋势Air空气testing/modeling in, 对……实验/建模useful numbers for, 关于……的有用数字Airbus Industrie, 空中客车产业Aircraft航行器airfoils机翼new designs, 新型设计Airfoils, 翼型aspect ratio (AR), 展弦比cambered, 弧形的drag coefficient of , 阻力系数early, 早期的Kline-Fogleman, 克莱恩-佛莱曼lift coefficient, 升力系数NACA,(美国) 国家航空咨询委员会separation bubble, 分离泡stalls and, 失速stall speed, 失速速度starting vortex, 起动涡stopping vortex, 终止涡Airfoil theory, 翼型理论flat-plate vortex sheet theory, 平板面涡理论Kutta condition, 库塔条件Kutta-Joukowski theorem, 库塔-儒科夫斯基定理1thick cambered airfoils, 厚弧面翼型thin-airfoils, 薄翼型wings of finite span, 有限展宽的翼型A-380 jumbo jet, 大型喷气式客机Alternate states, 交替状态American multiblade farm HA WT, 美式农庄多叶水平轴风机Angle of attack, 攻角Angle valve, 角阀Angular momentum角动量differential equation of , 关于…的微分方程relation/theorem, 联系/理论Annular strips, 环形带Applied forces, linear momentum, 外加力，线性冲力Apron,of a dam, 大坝的护坦Arbitrarily moving/deformable control volume, 任意运动/可变形控制体Arbitrary fixed control volume, 任意固定控制体Arbitrary viscous motion, 随机粘性运动Archimedes, 阿基米德Area changes, isentropic flow. 域变换，等熵流Aspect ratio (AR), 展弦比Automobiles, aerodynamic forces on, 汽车，气动力A verage velocity, 平均速度Axial-flow pumps. 轴流泵Axisymmetric flow, stream function 轴对称流，流函数Axisymmetric Potential flow, 轴对称有势流hydrodynamic mass, 水力学质量Point doublet, 点偶极子point source or sink, 点源与点汇spherical Polar coordinates and, 球极坐标uniform stream in the x direction, x方向的均匀流uniform stream plus a point doublet, 均匀流附加点偶极子uniform stream plus a point source, 均匀流附加点源BBackward-curved impeller blades, 后向曲叶轮片,Backwater curves, 回水曲线Basic equations, non dimensional, 基本方程，无量纲的Bernoulli obstruction theory, 伯努利障碍理论Bernoulli's equation, 伯努利方程with adiabatic and isentropic steady flow, as绝热、等熵稳态流frictionless flow, 无摩擦流assumptions/restrictions for, 假想/约束HGLs and EGLs, 水力坡度线和能量梯度线steady flow energy and, 定常流动能量in rotating coordinates. 在旋转坐标下，Best efficiency point (BEP), pumps, 最佳效率点，Betz number, 贝兹数Bingham plastic idealization, 宾汉塑性理想化，Biological drag reduction, 生物学阻力衰减Blade angle effects, on pump head, 叶片安装角效率，泵头处Blasius equation, 布拉修斯方程Body drag, at high Mach numbers, 机体阻力，在高马赫数下Body forces, 体力Boeing Corp., 波音公司Boundaries, of systems, 边界，系统Boundary conditions. 边界条件，differential relations for fluid flow, 流体的微分关系nondimensionalizalion and, 无量纲化Boundary element method (BEM), 边界元方法2Boundary layer (BL) analysis, 边界层分析boundary layer flows, 边界层流动boundary layer separation on a half body, 边界层半体分离displacement thickness, 位移厚度drag force and, 阻力equations, 方程flat-plate. 平板，Karman's analysis, 卡门分析momentum integral estimates, 动量积分估计momentum integral relation. 动量积分关系momentum integral theory, 动量积分理论pressure gradient 压力梯度separation on a half body, 半模分离skin friction coefficient, 表面摩擦系数two-dimensional flow derivation, 二维流推导Boundary layers with Pressure gradient, 边界层压力梯度adverse gradient, 反梯度favorable gradient, 正梯度laminar integral theory, 层流积分理论，nozzle-diffuser example,喷口扩散算例Bourdon tube, 波登管Bow shock wave, 弓形激波Brake horsepower,制动马力Broad-crested weirs, 宽顶堰Buckingham Pi Theorem, 白金汉定理Bulb Protrusion, 球形突出物（船头）Bulk modulus. 体积模量Buoyancy, 浮力Buoyant particles, local velocity and, 悬浮颗粒，局部速度Buoyant rising light spheres, 浮力作用下自由上升的球体Butterfly valve, 蝶形阀CCambered airfoils, 弓型翼Cauchy-Riemann equations, 柯西-黎曼方程Cavitation/Cavitation number, 气穴/气蚀数Celsius temperature scales, 摄氏温标Center of buoyancy, 浮心Center of Pressure (CP),压力中心，压强中心Centrifugal pumps, 离心泵backward-curved impeller blades, 后曲叶轮片blade angle effects on pump head, 泵头处叶片安装角效率brake horsepower, 制动马力circulation losses, 环量损失closed blades, 闭叶片efficiency of, 效率的elementary pump theory. 基泵理论Euler turbomachine equations, 欧拉涡轮机方程eye of the casing, 泵体通风口friction losses, 摩擦损失hydraulic efficiency, 水力[液压]效率mechanical efficiency.机械效率open blades, 开放式叶片output parameters, 输出参数power, delivered, 功率，传递pump surge, 泵涌，scroll section of casing, 卷形截面，泵体，shock losses, 激波损失vaneless, 无叶片的3volumetric efficiency, 容积效率[系数]water horsepower, 水马力Centripetal acceleration, 向心加速度Channel control Point, 传送控制点Characteristic area. external flows, 特征区域，外流Chezy coefficient, 薛齐系数Chezy formula, 薛齐公式Chezy coefficient,薛齐系数flow in a Partly full circular pipe, 流体非充满的圆管流Manning roughness correlation. 曼宁粗糙度关系，normal depth estimates, 法向深度估计Choking, 壅塞；堵塞of compressors, 压缩机的due to friction, compressible duct and, 由于摩擦，可压缩管的isentropic flow with area changes, 变横截面积等熵流simple heating and, 单纯加热Circular cylinder, flow with circulation. 圆柱体，Circulation环量and flow past circular cylinder, 流体经过圆柱体losses, in centrifugal pumps, 损失，离心泵potential flow and, 有势流Circumferential pumps, 环型泵Classical venturi, 标准文氏管Closed blades, centrifugal pumps. 闭叶片，离心泵Closed-body shapes, 闭体外形，circular cylinder, with circulation, 圆柱体，环量Kelvin oval, 开尔文椭圆，Kutta-Joukowski lift theorem,库塔－儒科夫斯基升力定理，Potential flow analogs, 有势流模拟Rankine oval, 兰金椭圆rotating cylinders. lift and drag, 旋转柱体，升力与阻力Coanda effect, 柯恩达效应( 沿物体表面的高速气流在Cobra P-530 supersonic interceptor, 眼镜蛇超音速拦截机Coefficient matrix. 系数矩阵Coefficient of surface tension, 表面张力系数Coefficient of viscosity, 粘滞系数Commercial CFD codes, viscous flow, 商业的计算流体力学代码，粘流Commercial ducts, roughness values for, 商业管道Composite-flow, open channels, 合成流，开槽道Compressibility, non dimensional. 压缩性，无量纲Compressibility effects, 压缩效果Compressible duct flow with friction, 伴有摩擦的可压缩管流adiabatic, 绝热的, 隔热的choking and, 壅塞；堵塞isothermal flow in long pipelines, 管线中的等温流动，long pipelines, isothermal flow in, 管线，等温流动，mass flow for a given pressure drop, 给定压降下质量流动minor losses in, 最小损失subsonic inlet, choking due to friction, 亚音速进口，摩擦引发阻塞，supersonic inlet, choking due to friction, 超音速进口，摩擦引发阻塞，Compressible flow, 可压缩流flow with friction摩擦流choking and, 壅塞；堵塞converging-diverging nozzles, 拉瓦尔喷管converging nozzles, 收缩喷嘴Fanno flow, 法诺流动，gas flow correction factor, 气流校正参数hypersonic flow, 高超音速气流4incompressible flow, 不可压缩流isentropic.等熵的isentropic Process, 等熵过程，Mach number, 马赫数normal shock wave. 正激波the perfect gas, 理想气体Prandtl-Meyer waves. 普朗特－麦耶膨胀波shock waves. 激波specific-heat ratio, 比热比speed of sound and,声速subsonic, 亚音速的supersonic,超音速的transonic, 跨音速的two-dimensional supersonic, 二维超音速的Compressible gas flow correction factor, 可压缩气流校正因数Compressors, 压缩机Computational fluid dynamics (CFD), 计算流体力学pump simulations, 泵模拟viscous flow. 粘流Concentric annulus, viscous flows in, 同心环Cone flows, 锥体绕流Conformal mapping, 保角映射[变换] Conservation of energy, 能量守恒定律Conservation of mass. 质量守恒定律Consistent units, 相容单元Constants, 常量dimensional, 空间的pure, 纯粹的Constant velocity, fluid flow at, 常速度, 等速度Constructs, 结构Contact angle, 交会角Continuity, 连续性，equation of ,方程nondimensionalization and, 无量纲的Continuum, fluid as, 连续流体Contraction flow, 收缩流动Control Point, channel, 控制点，管道Control volume analysis,控制体分析angular momentum theorem. 角动量定理，arbitrarily moving/deformable CV,任意运动/可变形控制体arbitrarily fixed control volume, 任意固定控制体conservation of mass, 质量守恒定律control volume moving at constant velocity, 控制体以等速运动control volume of constant shape but variable velocity作变速运动的刚性控制体energy equation. 能量方程introductory definitions, 介绍性定义linear momentum equation. 线性动量方程，one-dimensional fixed control volume, 一维固定控制体，one-dimensional flux term approximations, 一维通量项近似Physical laws. 物理定律。
FMCW-ISAR对舰船目标成像脉内补偿方法研究
FMCW-ISAR对舰船目标成像脉内补偿方法研究王勇;黄鑫【摘要】调频连续波逆合成孔径雷达(FMCW-ISAR)具有造价低、功耗低和重量轻的优点，因此被广泛用于对各类目标成像。
FMCW信号可以看作是占空比为1的脉冲信号，其脉冲宽度相对较长，在此期间内目标的运动常常不可忽略。
此时，利用传统的“走-停”模式和距离-多普勒(R-D)算法得到的ISAR像将出现距离-方位2维的模糊，导致图像分辨率下降。
该文针对FMCW-ISAR对舰船目标实测数据成像时出现的模糊现象进行了研究，首先建立目标的运动模型，并分析目标在调频周期内的运动分量对距离压缩结果和最终成像结果的影响，最后提出相应的脉内补偿方法以改善图像分辨率。
对比补偿前后对仿真模型与实测数据的成像结果，该文所提出的脉内补偿方法能够有效抑制1维距离像的展宽，提高FMCW-ISAR的成像质量。
%Given its advantages of low cost, low weight, and low power consumption, Frequency Modulated Continuous Wave-Inverse Synthetic Aperture Radar (FMCW-ISAR) has been widely used for imaging many kinds of targets. Since the FMCW signal can be regarded as a pulse signal whose duty ratio is one and pulse duration is relatively long, the motion of targets usually cannot be neglected. In this circumstance, the stop-go assumption is not valid, so ISAR images obtained using the traditional Range-Doppler (R-D) procedure exhibit two-dimensional blurring, which results in decreased resolution. In this paper, we investigate the blur problems of FMCW-ISAR in imaging ship targets, and construct a target motion model. Then, we analyze the influence of the in-pulse motion component in range profiles and final images. We propose acorresponding in-pulse compensation method to improve the resolutionof ISAR images. A comparison with the imaging results of real measured echo data verifies the effectiveness of the proposed method in diminishing the 1-D-profile broadening and improving image quality.【期刊名称】《雷达学报》【年(卷),期】2019(008)003【总页数】9页(P373-381)【关键词】调频连续波逆合成孔径雷达; 舰船目标成像; “走-停”模式; 脉内补偿;【作者】王勇;黄鑫【作者单位】哈尔滨工业大学电子与信息工程学院 ??哈尔滨 ??150001;哈尔滨工业大学电子与信息工程学院 ??哈尔滨 ??150001【正文语种】中文【中图分类】TN957.511 引言逆合成孔径雷达(Inverse Synthetic Aperture Radar, ISAR)成像是对海探测中很重要的精细化描述和识别手段[1]。
超声英文简写
超声常用术语英语解释2D：two-dimensional 二维3D: three-dimensional 三维AAO: ascending aorta 升主动脉AbAO: abdominal aorta 腹主动脉ABD: automatic borderline determination 自动边缘检测AC: accessory chamber 附属腔AD: acoustic densitometry 声学密度定量AML: anterior mitral leaflet 二尖瓣前叶AMV: anterior mitral valve 二尖瓣前叶AN: anuerysm 动脉瘤AO: aorta or aorta root 主动脉或主动脉根部AoAR: aortic arch 主动脉弓AoS: aortic sinus 主动脉窦AQ: acoustic quantification 声学定量ARCH: aortic arch 主动脉弓ARV: atrialized right ventricle 房化右室ASD: atrial septal defect 房间隔缺损ATL: anterior tricuspid leaflet 三尖瓣前叶ATV: anterior tricuspid valve 三尖瓣前叶A V: aortic valve 主动脉瓣AW: anterior wall 前壁CABG: coronary artery bypass grafting冠状动脉旁路血管移植术CDFI: color Doppler flow imaging 彩色多普勒血流成像CDFM: color Doppler flow mapping 彩色多普勒血流成像CK: color kinesis 彩色室壁动态技术CO: cardic output 心排出量CPV: common pulmonary vein 肺总静脉CS: coronary sinus 冠状静脉窦CS: crista supraventricularis 室上嵴CT: chordae tendinae 腱索CV: common ventricle 共同心室CW: continuous wave Doppler 连续型多普勒DA: dissecting aneurysm 夹层动脉瘤DAO: descending aorta 降主动脉DSE: Dobutamine stress echocardiography 多巴酚丁胺负荷超声心动图DTI: Doppler tissue imaging 组织多普勒成像技术DV: ductus venosus 静脉导管ECG: electrocardiogram 心电图EN: endocardium 心内膜EP: epicardium 心外膜EPSS: E point-septal seperation E 峰至室间隔间距ET: ejection time 射血期FCR: flow convergence region 血流汇聚区FFT: fast Fourier transformation 快速富利叶转换FL: false lumen 假腔HPLA: high pressure left atrium 左房高压腔HR: heart rate 心率HV: hepatic vein 肝静脉Hz: Hertz 赫兹I A S: interatrial septum 房间隔LA: left atrium 左房IBS: integral of backscatter 背向散射积分IVC: inferior vena cava 下腔静脉IVS: interventricular septum 室间隔IVUS: intravascular ultrasound 血管内超声IW: interior wall 下壁VSD: ventricular septal defect 室间隔缺损LAA: left atrial auricle 左心耳VV: vertical vein 垂直静脉LAD: left anterior descending coronary atery 左冠状动脉前降支LCA: left coronary artery 左冠状动脉LCC: left circumflex coronary artery 左冠状动脉回旋支LD: long diameter 长径LIV: left innominate vein 左无名静脉LPA: left pulmonary artery 左肺动脉VC: vena cava 腔静脉LPEP: left ventricular pre-ejection period左室射血前期LPLA: low pressure left atrium 左房低压腔LPV: left pulmonary vein 左肺静脉L-RD: left-right diameter 左右径LSVC: left superior vena cava 左位上腔静脉LV: left ventricle 左室LVC: left ventricular cavity 左室腔LVET: left ventricular ejection time 左室射血时间V: vegetation 赘生物LV I T: left ventricular inflow tract 左室流入道LV O T: left ventricular outflow tract 左室流出道LVPW: left ventricular posterior wall 左室后壁LW: lateral wall 侧壁m／s: 米/秒 MHz: 兆赫MCE: mycardial contrast echocardiogrphy 心肌声学造影M-LD: medial-lateral diameter 内外径M-mode: motion mode M型（超声心动图）MPA: main pulmonary artery 主肺动脉MV: mitral valve 二尖瓣MVP: mitral valve prolapse 二尖瓣脱垂PE: pericardial effusion 心包积液PA Bif: pulmonary artery bifurcation 肺动脉分叉PDA: patent ductus arteriousus 动脉导管未闭PM: papillary muscle 乳头肌PMV: posterior mitral valve 二尖瓣后叶PRF: pulsed repetition frequency 脉冲重复频率RA: right atrium 右房RPV: right pulmonary vein 右肺静脉PTV: posterior tricuspid valve 三尖瓣后叶PW: pulsed wave Doppler 脉冲型多普勒RCA: right coronary artery 右冠状动脉RIV: right innominate vein 右无名静脉RPA: right pulmonary artery 右肺动脉RPEP: right ventricular pre-ejection period 右室射血前期RSVC: right superior vena cava 右位上腔静脉RUPV: right upper pulmonary vein 右上肺静脉RLPV: right low pulmonary vein 右下肺静脉RV: right ventricle右室RV AW: right ventricular anterior wall 右室前壁RVC: right ventricular cavity 右室腔TL: true lumen 真腔RVET: right ventricular ejection time 右室射血时间RVOT: right ventricular out tract 右室流出道RWMA: regional wall motion abnormality 节段性室壁运动异常SAM: systolic anterior motion 二尖瓣收缩期前向运动SHI: second harmonic imaging 二次谐波成像技术SV: sampling volume or strake volume 取样容积或心搏量TEE: transesophageal echocardiography 经食管超声心动图TGA: transposition of the great arteries 大动脉转位TH: thrombosis 血栓形成ThAO: thoracic aorta 胸主动脉TMLR or TMR: transmyocardial laser revascularization 激光心肌血运重建术TTE: transthoracic echocardiography 经胸超声心动图TV: tricuspid valve 三尖瓣仪器和原理方面：切面面积Cross sectional Area (CSA)扫描器、探头Scanner (SCNR)凸形、凸阵Convex (CVX)扇扫角度Sector Angle (Sec Ang)辉度、亮度Brightness冻结Freeze (FRZ)平均速度Mean Velocity (Mean Vel)增益Gain返流Reversed Flow (RF)频谱Frequency Spectrum彩色多普勒血流显像Color Doppler Flow Imaging (CDFI)经颅多普勒Transcranial Doppler ( TCD)腹部血流显示Abdominal Flow Display (AFD)阴道超声Transvagin Scan (TVS)解剖学方面1）妇产科：胎盘Placenta (PL)胎心Fetal Heart (F Ht)胎头Fetal Head (FH)胎头指数Cephalic Index大脑镰Falx Cerebri (FC;FL)丘脑、视丘Thalmus (Th)侧脑室Lateral Ventricle (LV)第三脑室Third Ventricle (V3)透明隔Septum Pellucidum (SP)透明隔腔Septum Pellucidum (SP)蜕膜Decidua脐带Umbilical Cord (UC)绒毛Villus绒毛膜Chorion (C )羊水Amniotic Fluid (AF)羊水指数Amniotic Fluid Index (AFI)子宫内口Internal Ostium of the Uterius妊娠囊Gestational Sac (GS)双顶径Biparietal Diameter (BPD)股骨径Femur Length (FL)子宫口Orifice of the Uterius顶臀长度Crowm-Rump Length (CRL)胸围Thoracic Circumference (Th C)腹围Abdominal Circumference (AC)阴道Vagina头围Head circumference (HC)枕额径Occipital Frontal Diameter (OFD)子宫Uterus输卵管Uterine Tube,Oviduct卵巢Ovary, Ovaries (Ov)子宫颈Cervix (C )子宫腔Urterine Canal子宫内膜Endometriosis (En)卵黄囊Yolk Sac (YS)眼、面颈、涎腺、乳腺、胸腔：眼球Optic Bulb; Eyeball角膜Cornea前房Anterior Chamber(AC )虹膜Iris睫状体Ciliary Body视网膜Retina脉络膜Choroid巩膜Sclera房水Aqueous Humour玻璃体Vitreous晶状体Lens腮腺Parotid颌下腺Submaxillay Gland舌下腺Sublingual Gland甲状腺Thyroid甲状旁腺Parathroid乳腺Breast横膈Diaphragm (D)胸腔Thoracic cavity血管：腹主动脉Abdominal Aorta (AA)腹腔动脉Celiac Artery (Ce A;CA)肠系膜上动脉Superior Mesenteric Artery (SMA) 胃左动脉Left Gastric Artery脾动脉Splenic Artery (Sp A)肾动脉Renal Artery (RA)肾静脉Renal Vein (RV)门静脉Portal Vein (PV)肝静脉Hepatic Vein (HV)肝中静脉Medial Hepatic Vein (MHV)肝左静脉Left Hepatic Vein(LHV)腋静脉Axillary Vein肝右静脉Right Hepatic Vein (RHV)下腔静脉Inferior Vena Cava (IVC)肠系膜上静脉Superior Mesenteric Vein (SMV) 锁骨下静脉Subclavian Vein (SCV)颈外静脉External Jugular Vein颈内静脉Internal Jugular Vein颈总动脉Common Jugular Artery髂内动脉Internal Iliac Artery髂外动脉External Iliac Artery髂总动脉Common Iliac Artery大隐静脉Great Saphenous Vein小隐静脉Short Saphenous Vein股动脉Femoral Artery股静脉Femoral Vein腘动脉Popliteal Artery腘静脉Popliteal Vein足背动脉Dorsal Pedal Artery肝、胆、胰、脾、泌尿生殖：肝左叶Left Liver Lobe (LL)肝右叶Right Liver Lobe (RL)尾状叶Caudate Lobe (CL)方叶Quadrate Lobe (QL)胆囊Gallbladder (G)胆囊管Cystic Duct (CD)肝管Hepatic Duct (HD)胆总管Common Bile Duct (CBD)肝门Porta Hepatis肝总管Common Hepatic Duct (CHD)胰腺Pancreas (P;Pa)胰管Pancreatic Duct (PD;PaD)副胰管Santorini Duct (SD)胰头Head of Pancreas (PaH)胰颈Neck of Pancreas (PaN)胰体Body Of Pancreas (Pa)胰尾Tail of Pancreas (PaT)钩突Uncinate Process脾Spleen (Sp)肾Kidney (K)肾盂Renal Pelvis (RP)肾盏Renal Calyces (RC)肾锥体Pyramids (Py)肾柱Renal Colums (Rco)肾上腺Adrenal Gland (AG)输尿管Ureters (Ur)膀胱Urinary Bladder (U,Bladder (BL)前列腺Prostate (Pro)尿道Urethra睾丸Testis (Ts)副睾Epididymis (Ep)鞘膜Tunica Vagialis, Vagina Tunic腹股沟Inguen精囊Vesiculae Seminals; Seminal Vesicle (SV) 阴囊Scrotum (Sc),Scrotal Sac (SS)精索Spermatic Cord胃肠：胃Stomach (STO)贲门Cardia (C ),(Ca)胃底Fundus of Stomach (SF)胃体Body of Stomach (S)幽门Pylorus (Py)十二指肠Duodenum (Du)小肠Small Intestine空肠Jejunum回肠Ileum盲肠Cecum阑尾Appendix (Ap)大肠Large Intestine结肠Colon (Co)结肠肝曲Hepatic Flexure of Colon 肠系膜Mesentery结肠脾曲Splenic Flexure of Colon 升结肠Ascending Colon (As C)横结肠Transverse Colon (Tr C)降结肠Descending Colon (De C ) 乙状结肠Sigmoid Colon直肠Rectum肌肉、骨关节：肌肉Muscle, Musculus (M)肌腱Tendon Tendon腓骨Fib腰大肌M.Psoas Major尺骨Ulna脊柱Verebral Colum, Spine椎骨Vertebra (V)半月板Meniscus肱骨Humerus脊柱裂Spina Bifida (S)桡骨Raduis股骨Fumur胫骨Tibiaula颅骨Skull ,Cranial Bones髂骨Ilium髋骨Hip髂嵴Iliac Creast关节Joint其它：脓肿Abscess (ABS)钙化Calcification (CAL)肌瘤Myoma (MYO)结核Tuberculosis (T)蛔虫Ascariasis (As)淋巴结Lymph node (LN)肿瘤Tumor (T)包块Mass( M)结节Node (N)壁Wall (W)积液Effusion (Eff)腹水Ascites (ASC)坏死Necrosis (Nec)结石Stone (St)靶团Target (TAR)血肿Hematoma (HMA)血栓Thrombus (Th)纤维化Fibrosis (Fib)疤痕Scar (Sc)囊肿Cyst (Cy)脂肪瘤Lipoma淋巴瘤Lymphoma错构瘤Hamartoma异物Foreign Boby (F)栓塞Embolism粪石Fecalith (Fe)胆道蛔虫Bile Dull Ascariasis (BDAS)转移灶Metastasis (Met)沉积物Sediment (Sed)针尖Needle Tip (NT)血管瘤Angioma (ANG)宫内节育器Intrauterine Devices (IUD)消化系统肝脏L 尾状叶CL 方叶QL 肝总管CHD 肝管HD肝外胆管EHBD 圆韧带HUL 胆囊GB 胆总管CBD 胰管ＰD镰状韧带FL 门静脉PV 胰腺PA 胰头PA 胰体PAB淋巴结L YN 胆囊管CD 胰尾PAT 脾动脉SPA 脾SP脊柱Spine 左肝管LHD 胃STO 胃底SF 胃体SB十二指肠DU 幽门PY 肠BO 升结肠ASC 结肠CO降结肠Dec 横结肠Tre泌生肾上腺AG 肾K 肾盂RP 肾盏RC 肾柱Rco肾动脉RA 肾静脉RV 尿道UR 睾丸TS 附睾EP输尿管UR 前列腺PST 阴囊S 精囊SV 膀光BL子宫内膜En 子宫UT 卵巢OV 阴道S 卵泡Fou心血管系统腹主动脉AO 奇静脉AIV 腘动脉POA 肱静脉BV腹腔动脉CA 脐静脉UV 腓动脉PEA 桡静脉RV肠系膜上动脉SMA 肱动脉BA 腋静脉AxV 桡动脉RA肠系膜上静脉SMV 尺动脉UA 腋动脉AxA 股总动脉CFA肠系膜下静脉IMV 上肢静脉UEV 腘静脉POV 股浅动脉SFA肠系膜下动脉IMA 上肢动脉UEA 椎动脉V A 股深动脉DFA颈内动脉ICA 胫前静脉ATV 椎静脉VV 胫前动脉ATA颈内静脉IJV 胫后静脉PTV 大隐静脉GSV 胫后动脉PTA基底动脉V A 颈总动脉CCA 小隐静脉SSV 足背动脉DPA锁骨下动脉SCA 颈外动脉ECA 上腔静脉SVC 下肢静脉LEV锁骨下静脉SCV 无名静脉INA 下腔静脉IVC 髂总静脉CIV髂总动脉CIA 无名动脉INA 肾静脉RV 髂内静脉IIV髂内动脉ILA 股浅静脉SFV 腓静脉PEV 髂外静脉EIV髂外动脉EIA 股深静脉DFV 股总静脉CFV 血栓TH主动脉弓AOAR 血管瘤ANG产科胚胎Emb 胎儿 F 胎盘FC 胎心FHT 胎头FH脐带UC 羊水AF 头围HC 胸围Thc 腹围AC妊娠囊GS 双顶径BPD 枕额径OFD 头臀长CRT异常脂肪瘤Lipoma 结节N 脓肿ABS 积液Eff 腹水AS坏死Nec 钙化CAL 异物FB 结石ST 肿瘤T血肿HMA 肌瘤MYO 纤维化Fib 疤痕SC 囊肿CY错构瘤FETAL 肿块MAO 腹主动脉CA 腹腔动脉SMA 肠系膜上动脉SMV 肠系膜上静脉CHA 肝总动脉HA 肝动脉SA 脾动脉IVC 下腔静脉PV 门静脉RPV 门静脉右支LPV 门静脉左支SPJ 脾门融合SV 脾静脉RHV 右肝静脉MHV 中肝静脉LHV 左肝静脉RRV 右肾静脉RRA 右肾动脉LRV 左肾静脉LRA 左肾动脉L 肝脏RL 肝右叶LL 肝左叶CL 尾叶PHT 门脉高压L 肝癌N 结节T 肿瘤HMAS 血肿ABS 脓肿CY 囊肿AS 角征HS 驼峰征ANG 血管瘤HP 冰雹状TAR 靶团SP 脾脏TSP 移植脾 D 隔肌ASC 腹水GB 胆囊RBD 右胆管LBD 左胆管ST 结石BDAS 胆道蛔虫SH 声影CBD 总胆管P 胰腺WD 胰管PCY 假性囊肿DU 十二指肠LY 淋巴LYMA 淋巴瘤PE 胸水AA 动脉瘤FH 胎头TP 双胎BPD 双顶径HDY 脑积水ANY 无脑畸形MES 脑脊膜膨出TH 丘脑LVS 侧脑室3rdV 第三脑室FL 大脑镰SP 脊柱SB 脊柱裂THX 胸部H 心脏STO 胃BO 肠SC 阴囊UV 脐静脉UC 脐带AF 羊水PL 胎盘UT 子宫 C 宫颈V 阴道OV 卵巢MYO 肌瘤FN 内膜HM 葡萄胎GS 妊囊DCY 皮样囊肿UBI 双角子宫PU 幼稚子宫M 包块BL 膀胱K 肾脏LAG 左肾上腺RAG 右肾上腺PST 前列腺【超声基础方面】超声成像ultrasonic imaging实时成像real-time imaging灰阶显示gray scale display彩阶显示color scale display经颅多普勒transcranial doppler彩色多普勒血流显像color doppler flow imaging彩色血流造影color flow angiography彩色多普勒能量图color doppler energy彩色能量图color power angio超声内镜ultrasound endoscope超声导管ultrasound catheter血管内超声intravascular ultrasound血管内超声显像intravascular ultrasonic imaging管腔内超声显像intraluminal ultrasonic imaging腔内超声显像endoluminal sonography心内超声显像intracardiac ultrasonic imaging内镜超声扫描endoscopic ultrasonography内镜超声技术endosonography膀胱镜超声技术cystosonography阴道镜超声技术vaginosonography经阴道彩色多普勒显像transvaginal color doppler imaging经直肠超声扫描transrectal ultrasonography直肠镜超声（技术）rectosonography经尿道扫查transurethral scanning介入性超声interventional ultrasound术中超声监视intraoperative ultrasonic monitoring超声引导经皮肝穿刺胆管造影ultrasound guided percutaneous transhepatic cholangiography超声引导经皮穿刺注射乙醇US guided percutaneous alcohol injection超声引导经皮胆囊胆汁引流US guided percutaneous gallbladder bile drainage超声引导经皮抽吸US guided percutaneous aspiration超声引导胎儿组织活检US guided fetal tissue biopsy超声引导经皮肝穿刺门静脉造影US guided percutaneous transhepatic portography 三维显示three dimensional display三维图像重建3D image reconstruction组织特性成像tissue specific imaging动态成像dynamic imaging数字成像digital image血管显像angiography声像图法echography sonography声像图sonogram echogram多用途探头multipurpose scanner宽频带探头wide-band probe环阵相控探头phased annular array probe术中探头intraoperative porbe穿刺探头ultrasound guided probe食管探头transesophagel probe经食管超声心动图探头transesophagel echocardiography probe 阴道探头transvaginal probe直肠探头transrectal probe尿道探头transurethral probe膀胱探头intervesical probe腔内探头intracavitary probe内腔探头endo-probe导管超声探头catheter-based US probe扫描方式scan mode线阵linear array凸阵convex array扇扫sector scanning传感器sensor换能器transducer放大器amplifier阻尼器buffer解调器、检波器demodulator触发器trigger零位调整zero adjustment定标、校正calibration快速时间常数电路fast time constant自动增益控制automatic gain control深度增益补偿depth gain compensation时间增益补偿time gain compensation对数压缩logarithmic compression灵敏度时间控制sensitivity time control动态范围dynamic range消除erase, eliminate变换shift倒置、反转invert消除clear注释annotation放大magnification , magnify , zoom写入write记录record聚焦focus帧率frame rate冻结freeze字符character抑制rejection, reject , suppression增益gain帧相关frame correlation回放rendering , play back彩色极性color polarity彩色边界color edge彩色增强color enhance菜单选择menu selection彩色余辉color persistence彩色捕获color capture彩色壁滤波color wall filter彩色速度显像color velocity imaging彩色转向color steering彩色消除color cut彩色锁定color lock成像数据imaging data预设置preset前处理pre process后处理post process重调、复原reset动态频率扫描dynamic frequency scanning 焦距focal distance动态聚焦dynamic focusing滑动聚焦sliging focusing区域聚焦zone focusing连续聚焦sequential focusing电子聚焦electric focusing分段聚焦segment focusing多段聚焦multistage focusing全场连续聚焦confocusing图像均匀性image uniformity运动辨别力motion discrimination穿透深度penetration depth空间分辨力spatial resolution瞬时分辨力temporal resolution帧分辨力frame resolution图像线分辨力image-line resolution对比分辨力contrast resolution细节分辨力detail resolution多普勒取样容积doppler sample volume多普勒流速分布分辨力doppler flow-velocity distributive resolution 多普勒流向分辨力doppler flow-direction resolution多普勒最低流速分辨力doppler minimum flow-velocity resolution彩色多普勒空间分辨力spatial resolution of color doppler彩色多普勒时间分辨力time resolution of color doppler彩色多普勒最低流速分辨力minimum flow-velocity of color doppler 彩色多普勒强度color doppler level彩色多普勒处理功能板CFM processing board彩色视频监视器color video monitor【解剖学方面】1 颅脑大脑cerebrum大脑纵裂longitudinal cerebral fissure大脑皮质cerebral cortex大脑镰falx cerebri大脑导水管，中脑水管cerebral aqueduct中脑midbrain, mesencephalon小脑cerebellum小脑幕tentorium cerebella丘脑，视丘thalmus延髓medulla oblongata侧脑室lateral ventricle第三脑室third ventricle第四脑室fourth ventricle第五脑室fifth ventricle脑桥，桥脑pons脑干brain stem间脑diencephalon中间块intermidiate mass尾状核caudate nucleus脉络丛choroid plexus胼胝体corpus callosum脑岛，岛叶insula大脑脚cerebral peduncles大脑外侧沟（窝、裂）lateral sulcus , sylvius fissure穹窿fornix透明隔septum pellucidum透明隔腔cavity of septum pellucidum额叶frontal lobe顶叶parietal lobe枕叶occipital lobe颞叶temporale lobe缘叶limbic lobe大脑动脉环Willi's artery circle大脑前动脉anterior cerebral artery大脑中动脉middle cerebral artery大脑后动脉posterior cerebral artery基底动脉basilar artery前交通支（动脉）anterior communicating branch 后交通支（动脉）posterior communicating branch 颅前窝，凹anterior cranial fossa颅中窝，凹middle cranial fossa颅后窝，凹posterior cranial fossa2 眼、面颈、涎腺、乳腺、胸肺眼球optic bulb ,eyeball角膜cornea前房anterior chamber虹膜iris睫状体ciliary body视网膜retina脉络膜choroid巩膜sclera房水aqueous humour玻璃体vitreous玻璃体膜hyaloid membrae晶状体lens（眼）直肌recti muscles视神经optic nerve眶上动脉supraorbital artery眼动脉ophthalmic artery视网膜中央动脉central retinal artery睫状后长（短）动脉posterior long (short)ciliary artery泪腺动脉lacrimal gland artery滑车上动脉supratrochlear artery眼静脉ophthalmic vein眶上静脉suprorbital vein滑车上静脉supratrochlear vein视网膜中央静脉central retinal vein涡状静脉vorticose veins眼眶orbit结膜conjunctiva唾液腺、涎腺salivary gland腮腺parotid (gland)颌下腺submaxillary gland舌下腺sublingual gland甲状腺thyroid (gland )甲状旁腺parathyroid (gland )上颌窦maxillary sinus气管trachea食管esophagus乳腺breast, mammary gland额front枕occiput颞temples颊cheek胸廓、胸腔thorax, thorax cavity肋骨ribs, costae肋软骨costal cartilages胸骨sternum乳腺组织breast tissue悬韧带suspensory ligament, Copper's ligament 乳腺后组织retromammary tissue横膈diaphragm颈总动脉common carotid artery颈外动脉external carotid artery颈内动脉internal carotid artery椎动脉vertebral artery无名动脉innominate artery颈内静脉internal jugular vein甲状腺上动脉superior thyroid artery乳房内动脉internal mammary artery3 腹部血管、周围血管腹主动脉abdominal aorta腹腔动脉celiac artery肠系膜上动脉superior mesenteric artery肠系膜下动脉inferior mesenteric artery肝总动脉common hepatic artery肝动脉hepatic artery胃左动脉left gastric artery胃十二指肠动脉gastroduodenal artery脾动脉splenic artery肾动脉renal artery卵巢动脉ovarian artery髂总动脉common iliac artery髂内动脉internal iliac artery髂外动脉external iliac artery锁骨下动脉subclavian artery椎动脉vertebral artery乳房内动脉internal mammary artery颈内静脉internal jugular vein颈外静脉external jugular vein腋静脉axillary vein奇静脉azygos vein大隐静脉great saphenous vein下腔静脉inferior vena cava门静脉portal vein肠系膜上静脉superior mesenteric vein肝静脉hepatic vein肾静脉renal vein腰静脉lumbar vein精索静脉spermatic vein肾弓形动脉renal arcuate arteries股动脉femoral artery肱动脉humeral artery桡动脉radial artery尺动脉ulnar artery面动脉facial artery锁骨下动脉subclavian artery颈浅动脉superficial cervical artery颞浅动脉superficial temporal artery4 肝、胆、胰、脾、泌尿男生殖肝左叶left liver lobe(LL)肝右叶right liver lobe(RL)尾状叶caudate lobe(CL)方叶quadrate lobe(QL)附垂叶Riedel's lobe胆囊gallbladder(G)胆囊管cystic duct(CD)肝管hepatic duct(HD)胆总管common bile duct (CBD)肝门porta hepatis胆囊窝gallbladder forssa肝圆韧带hepatoumbilical ligament, round ligament 肝镰状韧带falciform ligament肝静脉韧带venose ligament胆管、胆道bile duct(BD)螺旋状瓣spiral valve肝总管common hepatic duct肝外胆管extrahepatic duct乏特壶腹Vater's ampulla胰腺pancreas胰管pancreatic duct , Wirsung's duct副胰管Santorini duct胰头head of pancreas胰颈neck of pancreas胰体body of pancreas胰尾tail of pancreas钩突uncinate process脾spleen脾门splenic hilum肾周脂肪perinephrit fat集合系统collective system肾kedney肾盂renal calyes锥体pyramids肾柱renal colums肾上腺adrenal gland输尿管ureters, ureteral , uretero膀胱urinary bladder , bladder尿道urethra睾丸testis附睾epididymis鞘膜tunica vagialis, vagina tunic白膜tunica albuginea , albuginea输精管ductus deferens, deferent duct 精囊vesiculae seminals, seminal vesicle 射精管ejaculatory ducts阴囊scrotum, scrotal sac精索spermatic cord腹股沟inguen前列腺prostate5 妇产科子宫uterus输卵管uterine tube, oviduct卵巢ovary, ovaries子宫颈cervix子宫腔uterine canal子宫内膜endometriosis子宫直肠陷凹rectouterine fossa子宫内口internal ostium of the uterus 子宫口orifice of the uterus阴道vagina胚胎embryo卵黄囊yolk sac羊膜amnion羊膜腔amniotic cavity蜕膜decidua绒毛villus绒毛膜chorion胎盘placenta胎儿fetus胎心fetal heart胎动fetal movement, feta motion胎儿脊柱fetal spine胎儿胃泡fetal stomach bubble胎儿胸部fetal thorax胎儿肾fetal kidney胎儿肢体fetal limb脐带umbilical cord卵泡，滤泡follicle附件adnexa羊水amniotic fluid宫内节育器intrauterine device妊娠囊gestational sac顶臀长度crown-rump length双顶径biparietal diameter胎头指数cephalic index枕额径occipito-frontal diameter头围head circumference胸围thoracic circumference腹围abdominal circumference小脑径cerebellum diameter头（径）指数cephalic index双眼间距ocular distance腹部横径transverse trunk diameter腹部前后径anteroposterior trunk diameter 椎骨长度（胸6～腰3）length of vertebrae 脊柱spine, vertebral colum股骨长度femur length肱骨长度humerus length胎儿体重fetal weight脐动脉umbilical artery脐静脉umbilical vein胎盘placenta孕周gestational week孕龄gestational age。
怎样在ABAQUS中加载波浪力
Set TYPE=USER to use user subroutine UWAVE to define the fluid particle velocities, accelerations, free surface elevation, and dynamic pressure and to specify when to update the intermediate configuration for stochastic analysis.
Direction cosines giving the direction of travel of the wave, d. In three-dimensional cases both x- and y-components are needed; in two-dimensional cases only the x-component is used (in that case +1 means the wave travels in the direction of x increasing, and 1 means a component traveling in the direction of x decreasing).
Optional parameters for TYPE=GRIDDED:
MINIMUM
Set this parameter equal to the elevation below which point the structure is fully immersed for all time t. If this parameter is omitted, the elevation of the structure is compared against the instan surface penetration.
机械原理术语英汉对照
机械原理重要名词术语中英文对照表Aarchimedesworm阿基米得蜗杆BFifth-powerpolynomialmotion五次多项式运动规律oscillatingfollower摆动从动件camwithoscillatingfollower摆动从动件运动规律oscillatingguide-barmechanism摆动导杆机构cycloidalgear摆线齿轮cycloidalmotion摆线运动规律cycloidal-pinwheel摆线针轮angleofcontact包角backcone背锥backangle背锥角backconedistance背锥距scale比例尺closedkinematicchain闭式运动链closedchainmechanism闭式链机构arm臂部modifiedgear变位齿轮modificationcoefficient变位系数standardspurgear标准直齿轮combineinparallel并联式组合amountofunbalance不平衡量intermittentgearing不完全齿轮wavegenerator波发生器numberofwaves波数Cgenevawheel槽轮genevamechanism槽轮机构groovecam槽凸轮backlash侧系differentialgeartrain差动轮系differentialscrewmechanism差动螺旋机构differentials差速器space齿槽spacewidth齿槽宽addendum齿顶高addendumcircle齿顶圆dedendum齿根高dedendumcircle齿根圆thickness齿厚circularpitch齿距facewidth齿宽toothprofile齿廓toothcurve齿廓曲线gear齿轮pinionandrack齿轮齿条机构pinioncutter齿轮插刀hob,hobbingcutter齿轮滚刀gears齿轮机构blank齿轮轮坯teethnumber齿数gearratio齿数比rack齿条rackcutter齿条插刀coincidentpoints重合点contactratio重合度transmissionratio,speedratio传动比transmissionangle传动角combineinseries串连式组合drivenpulley从动带轮drivenlink,follower从动件widthofflat-face从动件平底宽度followerdwell从动件停歇followermotion从动件运动规律drivengear从动轮Dbeltdrives带传动beltpulley带轮universaljoint单万向联轴节unitvector单位矢量equivalentspurgear当量齿轮equivalentteethnumber当量齿数equivalentcoefficientoffriction当量摩擦系数cutter刀具lead导程leadangle导程角constantaccelerationanddecelerationmotion等加速等减速运动规律constantdiametercam等径凸轮constantbreadthcam等宽凸轮uniformmotion,constantvelocitymotion等速运动规律equivalentlink等效构件equivalentforce等效力equivalentmoment等效力矩equivalentmass等效质量equivalentmomentofinertia等效惯性力lowerpair低副clearance顶隙ordinarygeartrain定轴轮系dynamicbalance动平衡dynamicbalancingmachine动平衡机dynamiccharacteristics动态特性dynamicreaction动压力dynamicload动载荷transverseplane端面transverseparameters端面参数transversecircularpitch端面齿距transversecontactratio端面重合度transversemodule端面模数transversepressureangle端面压力角inlinerollerfollower对心滚子从动件inlineflat-facedfollower对心平底从动件inlineslidercrankmechanism对心曲柄滑块机构in-linetranslatingfollower对心移动从动件polynomialmotion多项式运动规律rotorwithseveralmasses多质量转子idlergear惰轮Fgeneratingline发生线generatingplane发生面normalplane法面normalparamenters法面参数normalcircularpitch法面齿距normalmodule法面模数normalpressureangle法面压力角feedbackcombining反馈式组合inversecammechanism反凸轮机构inverse(backward)kinematics反向运动学kinematicinversion反转法generating范成法formcutting仿形法flywheel飞轮momentofflywheel飞轮距nonstandardgear非标准齿轮aperiodicspeedfluctuation非周期性速度波动noncirculargear非圆齿轮standardpitchline分度线standardpitchcircle分度圆standardpitchcone分度圆锥planetarydifferential封闭差动轮系additionalmechanism附加机构compoundhinge复合铰链compoundcombining复合式组合compoundscrewmechanism复式螺旋机构complexmechanism复杂机构Ginterference干涉rigidc ircularspline刚轮bodyguidancemechanism刚体导引机构rigidimpulse(shock)刚性冲击rigidrotor刚性转子higherpair高副grashoff’slaw格拉晓夫定理undercutting根切workingspace工作空间effectiveresistance工作阻力effectiveresistancemoment工作阻力矩workingstroke工作行程commonnormalline公法线generalconstraint公共约束metricgears公制齿轮power功率conjugateprofiles共轭齿廓conjugatecam共轭凸轮link构件fixedlink,frame固定构件jointedmanipulator关节型操作器inertiaforce惯性力partialbalanceofshakingforce惯性力部分平衡momentofinertia,shakingmoment惯性力矩balanceofshakingforce惯性力平衡fullbalanceofshakingforce惯性力完全平衡pathgenerator轨迹发生器hob，hobbingcutter滚刀roller滚子radiusofroller滚子半径rollerfollower滚子从动件undercutting过度切割Hfunctiongenerator函数发生器interchangeablegears互换性齿轮slider滑块return，return-stroke回程compoundgeartrain复合轮系Jmechanism机构analysisofmechanism机构分析balanceofbalance机构平衡mechanism机构学kinematicdesignofmechanism机构运动设计kinematicdiagram机构运动简图synthesisofmechanism机构综合constitutionofmechanism机构组成frame，fixedlink机架kinematicinversion机架变换machine机器robot机器人manipulator机器人操作器robotics机器人学machinery机械dynamicanalysisofmachinery机械动力分析dynamicdesignofmachinery机械动力设计dynamicsofmachinery机械动力学mechanicaladvantage机械利益balanceofmachinery机械平衡manipulator机械手mechanicalbehavior机械特性mechanicalefficiency机械效率mechanismsandmachinetheory,theoryofmecha nismsandmachines机械原理coefficientofspeedfluctuation机械运转不均匀系数fundamentalmechanism基础机构basecircle基圆radiusofbasecircle基圆半径basepitch基圆齿距pressureangleofbasecircle基圆压力角basecylinder基圆柱basecone基圆锥quick-returnmechanism急回机构quick-returncharacteristics急回特性quick-returnmotion急回运动ratchet棘轮ratchetmechanism棘轮机构pawl棘爪extremeposition极限位置crankanglebetweenextremepositions极位夹角computeraideddesign计算机辅助设计computerintegratedmanufacturingsystem计算机集成制造系统acceleration加速度accelerationanalysis加速度分析accelerationdiagram加速度曲线knife-edgefollower尖底从动件intermittentmotionmechanism间歇运动机构simpleharmonicmotion(SHMforshort)简谐运动involutehelicoid渐开线螺旋面involute渐开线involuteprofile渐开线齿廓involutegear渐开线齿轮generatinglineofinvolute渐开线发生线involuteequation渐开线方程involutefunction渐开线函数involuteworm渐开线蜗杆pressureangleofinvolute渐开线压力角simpleharmonicmotion简谐运动cross-beltdrive交叉带传动crossedhelicalgears交错轴斜齿轮angularacceleration角加速度angularvelocity角速度angularvelocityratio角速比correctingplane校正平面structure结构structuralandmechanicalerror结构误差pitchpoint节点pitchline节线pitchcircle节园thicknessonpitchcircle节园齿厚pitchdiameter节圆直径pitchcone节圆锥pitchconeangle节圆锥角analyticaldesign解析设计diametralpitch径节clearance径向间歇staticbalance静平衡passivedegreeoffreedom局部自由度absolutemotion绝对运动absolutevelocity绝对速度loadbalanc ingmechanism均衡装置Kopen-beltdrive开口传动openkinematicchain开式链openchainmechanism开式链机构spatialmechanism空间机构spatiallinkages空间连杆机构spatialcams空间凸轮机构spatialkinematicpair空间运动副spatialkinematicchain空间运动链blockdiagram框图Lpitchcurve理论廓线force力forcepolygon力多边形force-closedcammechanism力封闭型凸轮机构moment力矩equilibrium力平衡couple[offorces],couples力偶momentofcouple力偶矩connectingrod,couple连杆linkages连杆机构couplecurve连杆曲线lineofcenters连心线chainwheel链轮two-dimensionalcam两维凸轮criticalspeed临界转速six-barlinkage六杆机构blank轮坯geartrain轮系screw螺杆threadpitch螺矩nut,screwnut螺母threadofascrew螺纹helicalpair螺旋副screwmechanism螺旋机构helicalangle螺旋角helix,helicalline螺旋线Mmodule模数friction摩擦frictionangle摩擦角frictionforce摩擦力frictionmoment摩擦力矩coefficientoffriction摩擦系数frictioncircle摩擦圆end-effector末端执行器objectivefunction目标函数N mechanismwithflexibleelements挠性机构flexiblerotor挠性转子internalgear内齿轮ringgear内齿圈engaging-out啮出engagement,meshingengagement,meshing啮合meshingpoint啮合点angleofengagement啮合角contactingline,pressureline,lineofengagement 啮合线lengthofcontactingline啮合线长度engaging-in啮入nomogram诺模图Pdiskcam盘形凸轮parabolicmotion抛物线运动beltpulley皮带轮offsetdistance偏距offsetcircle偏距圆eccentric偏心盘offsetrollerfollower偏置滚子从动件offfserknife-edgefollower偏置尖底从动件offsetflat-facefollower偏置平底从动件offsetslider-crankmechanism偏置曲柄滑块机构frequency频率flatbeltdrive带传动flat-facefollower平底从动件facewidth平底宽度balance平衡balancingmachine平衡机balancingquality平衡品质correctingplane平衡平面balancemass,qualityofmass平衡质量counterweight平衡重balancingspeed平衡转速planarpair,flatpair平面副planarmechanism平面机构planarkinematicpair平面运动副planarlinkage平面连杆机构planarcam平面凸轮parallelhelicalgears平行轴斜齿轮Qothermechanismmostinuse其它常用机构startingperiod起动阶段pneumaticmechanism气动机构singularposition奇异位置initialcontact,beginningofcontact起始啮合点forcedvibration强迫振动depthofcut切齿深度crank曲柄grashoff’slaw曲柄存在条件rotationguide-barmechanism转动导杆机构slider-crankmechanism曲柄滑块机构crank-rockermechanism曲柄摇杆机构curvature曲率radiusofcurvature曲率半径curved-shoefollower曲面从动件curvematching曲线拼接drivingforce驱动力drivingmoment驱动力矩wholedepth全齿高sphericalpair球面副sphericalinvolute球面渐开线sphericalmotion球面运动sphere-pinpair球销副polarcoordinatemanipulator球坐标操作器Rherringbonegear，doublehelicalgear人字齿轮redundantdegreeoffreedom冗余自由度flexspline柔轮flexibleimpulse,softshock柔性冲击flexiblemanufacturingsystem柔性制造系统flexibleautomation柔性自动化Sthree-dimensionalcam三维凸轮kennedy’stheorem，theoremofthreecenters三心定理planetarydrivewithsmallteethdifference少齿差行星传动designvariable设计变量rise升程camprofile实际廓线realpart实部vector矢量outputwork输出功outputlink输出构件outputmechanism输出机构outputtorque输出力矩outputshaft输出轴inputlink输入构件mathematicalmodel数学模型double-slidermechanism,ellipsograph双滑块机构doublecrankmechanism双曲柄机构constant-velocityuniversaljoints双万向联轴节doublerockermechanism双摇杆机构oldhamcoupling双转块机构instantaneouscenter瞬心deadpoint死点four-barlinkage四杆机构velocity速度speedfluctuation速度波动coefficientofspeedfluctuation速度波动系数velocitydiagram速度曲线instantaneouscenterofvelocity速度瞬心Tsteppulley塔轮sungear太阳轮characteristics特性equivalentmechanism替代机构governor调速器stoppingphase停车阶段dwell停歇synchronousbeltdrive同步带传动cam凸轮cams,cammechanism凸轮机构camprofile凸轮(实际)廓线layoutofcamprofile凸轮廓线绘制pitchcurve凸轮理论廓线graphicaldesign图解设计rise推程Wexternalgear外齿轮externalforce外力universaljoint,hooke’scoupling万向联轴节wrist腕部reciprocatingmotion往复移动differentialscrewmechanism差动螺旋机构displacement位移displacementdiagram位移曲线pose,positionandorientation位姿steadymotionperiod稳定运转阶段robustdesign稳健设计worm蜗杆wormgearing蜗杆传动机构numberofthreads蜗杆头数diametralquotient蜗杆直径系数wormandwormgear蜗杆蜗轮机构wormgear蜗轮Xcrankarm,planetcarrier系杆fieldbalancing现场平衡centrifugalforce离心力relativevelocity相对速度relativemotion相对运动pinion小齿轮harmonicdrive谐波传动helicalgear斜齿圆柱齿轮stroke工作行程coefficientoftravelspeedvariation,advance-tore turn-timeratio行程速比系数planetgear行星轮planetgeartrain行星轮系planetcarrier行星架form-closedcammechanism形封闭凸轮机构virtualreality虚拟现实redundantconstraint虚约束imaginarypart虚部allowableamountofunbalance许用不平衡量allowablepressureangle许用压力角circulatingpowerload循环功率流Ypressureangle压力角jacobimatrix雅克比矩阵rocker摇杆hydrodynamicdrive液力传动hydraulicmechanism液压机构reciprocatingfollower移动从动件slidingpair,prismaticpair移动副prismaticjoint移动关节wedgecam移动凸轮incrementordecrementwork盈亏功optimaldesign优化设计detrimentalresistance有害阻力simpleharmonicmotion余弦加速度运动roundbeltdrive圆带传动circulargear圆形齿轮cylindricpair圆柱副cylindricalcam圆柱凸轮cylindricalworm圆柱蜗杆cylindricalcoordinatemanipulator圆柱坐标操作器bevelgears圆锥齿轮机构coneangle圆锥角drivinglink原动件constraint约束constraintcondition约束条件jerk跃度jerkdiagram跃度曲线kinematicinversion运动倒置kinematicanalysis运动分析kinematicpair运动副movinglink运动构件kinematicdiagram运动简图kinematicchain运动链motionskewness运动失真kinematicdesign运动设计cycleofmotion运动周期kinematicsynthesis运动综合coefficientofvelocityfluctuation运动不均匀系数Zload载荷generating展成法，范成法tensionpulley张紧轮vibration振动shakingcouple振动力矩frequencyofvibration振动频率amplitudeofvibration振幅tangentmechanism正切机构direct(forward)kinematics正向运动学sinegenerator,scotchyoke正弦机构spurgear直齿圆柱齿轮cartesiancoordinatemanipulator直角坐标操作器diametralquotient直径系数mass-radiusproduct质径积mid-plane中间平面centerdistance中心距centerdistancechange中心距变动centralgear中心轮finalcontact，endofcontact终止啮合点periodicspeedfluctuation周期性速度波动epicyclicgeartrain周转轮系togglemechanism肘形机构shaftangle轴角axialthrustload轴向分力drivinggear主动齿轮drivingpulley主动带轮rotatingguide-barmechanism转动导杆机构revolutepair转动副revolutejoint转动关节rotor转子balanceofrotor转子平衡assemblycondition装配条件bevelgear锥齿轮commonapexofcone锥顶conedistance锥距conepulley锥轮sub-mechanism子机构automation自动化self-locking自锁degreeoffreedom(dofforshort)自由度totalcontactratio总重合度resultantforce总反力overlapcontactratio纵向重合度combinedmechanism组合机构minimumteethnumber最少齿数minimumradius最小向径appliedforce作用力coordinateframe坐标系。
alevel物理u2知识点整理
alevel物理u2知识点整理English Answer：1. Motion.Describe motion in terms of displacement, speed, and acceleration.Derive and use the equations of motion:v = u + at.s = ut + 1/2 at^2。
v^2 = u^2 + 2as.Analyze motion in one and two dimensions, including projectiles.2. Forces and Dynamics.Define and apply Newton's three laws of motion.Use force diagrams to analyze forces acting on objects.Calculate the acceleration of an object due to a given net force.Apply the concepts of momentum and impulse in collisions.3. Energy.Define and explain the different types of energy: kinetic, potential (gravitational and elastic), and internal.Derive and use the equation for conservation of energy.Apply the concept of energy transfer and transformation.Analyze energy efficiency and power.4. Waves.Describe the characteristics of waves: wavelength, amplitude, frequency, and wave speed.Explain the relationship between wave speed, wavelength, and frequency.Apply the concepts of wave reflection, refraction, and interference.Use the Doppler effect to explain shifts in wave frequency.5. Electricity.Describe the structure of an atom and explainelectrical charge.Define and use Ohm's law for resistors.Analyze the behavior of resistors, capacitors, and inductors in circuits.Explain the concepts of electromotive force (EMF) and electrical power.6. Magnetism.Describe the magnetic field around a current-carrying wire and a permanent magnet.Explain the concepts of magnetic force and magnetic flux.Apply the concepts of electromagnetic induction to explain the operation of generators and transformers.7. Waves in Matter.Describe the properties of sound waves and explain the concept of resonance.Analyze the behavior of light waves and explain the concepts of reflection, refraction, and diffraction.Explain the principles of optical instruments such as telescopes and microscopes.8. Astrophysics.Describe the structure and evolution of stars.Explain the formation and properties of galaxies.Discuss the concepts of cosmology and the origin of the universe.Chinese Answer：1. 运动。
大连理工大学智慧树知到“选修课”《专业英语(计算机英语)》网课测试题答案3
大连理工大学智慧树知到“选修课”《专业英语（计算机英语）》网课测试题答案（图片大小可自由调整）第1卷一.综合考核(共15题)1.CD is designed to read the disks and translate the data into a it can process.()A.正确B.错误2.However what really triggered the tremendous growth of computers and its significant impact on our lives is the invention of the microprocessor.()A.正确B.错误3.An audio wave is a two-dimensional acoustic wave.()A.正确B.错误4.Click the backward Undo arrow to cancel the first action you performed.()A.正确B.错误5.Most networks-even those with just two computers also contain a hub or switch to act as a connection point between the computers.()A.正确B.错误6.The keyboard is classified as a of output.()A.正确B.错误7._____ is an operating system similar to Unix.A.Windows NTB.MS-DOSC.OS/2D.Linux8.A computer can be broken down into three distinct categories, namely output, and CPU.()A.正确B.错误9.It wasn't until the 1980's that people began buying computer for personal use.()A.正确B.错误10.The fourth generation computers can be characterized by both the jump to monolithic integrated circuits and the invention of _____.A.microprocessorB.transistorC.chipD.circuit11.A(n) _____ mouse emits and senses light to detect movement.A.cordlessB.opticalC.cameraD.microphone12.Each web page has a unique address, called a URL that identifies its location on the network.()A.正确B.错误13.A computer must include three of following. Which one is not necessary?A. systemB.output systemC.processing systemworking system14.A network interface on each computer, usually called a network interface card(NIC) or adapter.()A.正确B.错误15.Microsoft Office 2000 includes Word, _____, Outlook and FrontPage.A.ExcelB.Power PointC.AccessD.All of the above第2卷一.综合考核(共15题)1.Database management system(DBMS) programs are designed to work with data that is logically structured or arranged in a particular way, known as _____.A.data modelB.databaseC.inationD.data2.A _____ is a collection of relation fields.A.fieldB.recordC.characterD.file3.Which one is an image-editing tool?A.PhotoshopB.WordC.Extreme 3DD.Premiere4.To access the Web, users require a _____, which is the software program used to access the World Wide Web.A.Plug-insB.HelperC.Add-onsD.Web browser5.Telnet enables users to cute terminal sessions with local hosts.()A.正确B.错误6._____ provides reliable, full-duplex connections and reliable service by ensuring that data is resubmitted when transmission results in an error.A.TCPB.ARPC.UDPD.IP7.Click the open folder button to open an existing workbook.() A.正确B.错误8.Which of the following is not a format for a graphical image file?A.BMP fileB.GIF fileC.JPG fileD.AVI file9.TCP/IP application layer protocols include the following except _____.A.HTTPB.FTPC.UDPD.Telnet10.C is an object-oriented programming language.()A.正确B.错误11.Transistors were a tremendous breakthrough in advancing the computer.()A.正确B.错误12.A VPN offers the security and full data access of a private WAN, but because it runs over the Internet, it is more affordable and complex.()A.正确B.错误13.ERP is _____.A.Enterprise resource planning softwareB.Enterprise Application IntegrationC.Electronic Application IntegrationD.None of the above.e the spell checker to correct spelling errors on the worksheet.()A.正确B.错误15.FTP performs basic interactive file transfers between hosts.()A.正确B.错误第1卷参考答案一.综合考核1.参考答案：B2.参考答案：A3.参考答案：B4.参考答案：B5.参考答案：A6.参考答案：B7.参考答案：D8.参考答案：A9.参考答案：B10.参考答案：A11.参考答案：B12.参考答案：A13.参考答案：D14.参考答案：A15.参考答案：D第2卷参考答案一.综合考核1.参考答案：A2.参考答案：D3.参考答案：A4.参考答案：D5.参考答案：B6.参考答案：A7.参考答案：A8.参考答案：D9.参考答案：C10.参考答案：B11.参考答案：A12.参考答案：A13.参考答案：A14.参考答案：A15.参考答案：A。
二维波动方程泊松公式
二维波动方程泊松公式二维波动方程泊松公式（Two-Dimensional Wave Equation Poisson Formula）是一种描述物理过程的灵活且有效的工具，可用于模拟数值计算机模拟和理论研究。
它可以应用于气象学、化学反应、化学动力学、等离子体动力学以及热力学和流体力学等领域，用于计算平面的平均温度或压力，以及近似解决具有更复杂的热或流体现象的物理问题。
一、二维波动方程泊松公式的定义二维波动方程泊松公式（Two-Dimensional Wave Equation Poisson Formula）是在有限差分法和计算机模拟中应用的一个偏微分方程式，它描述了物理现象的局部温度或压力变化，主要是假定一定空间变化和一定形状波动时，一定时间变化的物理现象。
它可以用来模拟两维热或流体中本征方程的稳定参数，从而求出局部的温度或压力的变化。
二、二维波动方程泊松公式的误差二维波动方程泊松公式的近似误差是主要由于数值模拟的结果和真实物理现象之间存在差异造成的。
这是因为当运用数学方法来模拟物理现象时，它们描述的有限元件不能和完全精确再现真实现象，必然会有一定的误差。
尽管有这样的误差，二维波动方程泊松公式仍然被经常用于数值计算机中，因为它使计算迅速、简洁。
三、应用（1）气象领域：二维波动方程泊松公式可以用于模拟湍流气象情况，如风速、风向、风湍等，以便更好地预报天气。
（2）热力学领域：二维波动方程泊松公式可以用于模拟非绝热多相过程物理现象。
比如在结构图像该反应化学过程中，使用该方程可以得到局部的温度变化，从而进一步推导出整个反应所需要的条件。
（3）等离子体动力学领域：二维波动方程泊松公式也可以用于计算不同物理量在等离子体动力学现象中的变化，比如电流密度、电场强度、电子速度以及电子温度等。
（4）流体力学领域：二维波动方程泊松公式可以用来研究流体的实际效应，如液体的流变、湍流、传热等。
四、优势（1）具有很好的灵活性：根据需要调整边界条件，可以计算出不同情况下物理量的变化。
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small compared with the wavelength λ = 2π/k. Upon this assumption, the equations governing the motion of wave can be linearized.[8,9] According to the Taylor– Melcher leaky dielectric model,[3,4] we have
dF/dt = 0,
(6)
number Ne = Q20/ε0γk. Following the strategy illuminated by Prosperetti,[8] we haveቤተ መጻሕፍቲ ባይዱ
a˜(s) = a0s−1 + [u0s2 + C8s + C9 + C10 s + Oh
+ C11s−1( s + Oh − Oh)]χ˜(s + Oh), (11)
According to the electrical properties of the liquid, two cases are considered. Case 1: the liquid is a leaky dielectric. Case 2: the liquid is a perfect dielectric. The air is perfectly dielectric. For case 1, in the unperturbed state the liquid is equipotential, the air has a basic electric field of uniform strength V0/H in the y
in the Laplace space for case 1, where a˜ denotes the
Laplace transform of a, s is the Laplace variable con-
jugated to time, C8 − C11 are the coefficients, and
No. 7
LI Fang et al.
2547
∇2φ = 0, E = −∇φ,
(5)
where u, ρ, p, υ = µ/ρ, g, φ and E are the velocity, density, pressure, kinematic viscosity, gravitational acceleration, electric potential and electric field intensity, respectively, j is the unit vector in the y direction, ∇ is the gradient operator and ∇2 is the Laplacian operator. The boundary conditions at the surface include the kinematic boundary condition, balance of forces, continuity of tangential electric field and Gauss theorem, i.e.
CHIN.PHYS.LETT.
Vol. 25, No. 7 (2008) 2546
Two-Dimensional Wave Motion on the Charged Surface of a Viscous Liquid ∗
ÓǑ Ư ƨ LI Fang( ), YIN Xie-Yuan(
), YIN Xie-Zhen(
)∗∗
Department of Modern Mechanics, University of Science and Technology of China, Hefei 230027
(Received 10 March 2008)
The wave motion on the charged surface of a viscous Newtonian liquid is solved as an initial-value problem. Both the leaky dielectric and perfect dielectric cases are considered. The amplitude of wave is assumed to be small. The electric field induced by surface charge is shown to have a generally destabilizing effect on surface wave. The neutral stability curve is drawn in the (G, Ne) plane (G: the gravitational bond number; Ne: the electrical Bond number). The Ohnesorge number, Taylor–Melcher number and permittivity ratio have little influence on the neutral stability curve. It is testified that the classical normal mode method cannot predict wave behaviour at small times.
direction, and free charge of uniform density ε0V0/H is distributed on the surface between the liquid and air (ε0: the permittivity of the air). For case 2, the basic electric field intensities in the liquid and air are, respectively,
∇ · u = 0,
(3)
∂u ∂t
=
−
1 ρ
∇p
+
v∇2u
−
gj,
(4)
∗Supported by the National Natural Science Foundation of China under Grant No 10572137. ∗∗ Email: xzyin@ c 2008 Chinese Physical Society and IOP Publishing Ltd
E = V0/(D + εrH) and Ea = εrV0/(D + εrH), (1)
where the permittivity ratio εr = ε/ε0 (ε: the permittivity of the liquid). Subscript a denotes the air medium. There is no free charge in case 2.
Fig. 1. Sketch of the model.
The basic flow is assumed to be stationary. In the Cartesian coordinate system (x, y, z) as sketched in Fig. 1, the free surface subjected to a single harmonic wave is described by
PACS: PACS: 47. 35. −i, 47. 20. Ma
Liquid sheets and films are involved in applications related to coating, cooling, lithography, biological membrane, micro-scale and micro-gravitational systems, where an electric field is often used to control the behaviour of an interface.[1,2] For different purposes, electric field parallel to undisturbed interface or normal to it may be imposed. In most applications liquids are commonly leaky dielectric. That is, the electrical conductivity of the liquid is finite, and moreover, electrical shear force exists on the surface.[3,4]