查询词典 numerical constant

When the beam current is 7A, voltage is 90kV, the velocity ratio is 1.0 and the axial velocity spread is 2%, numerical results show a constant bandwidth of 20%with an efficiency 42%, the peak power and gain are, respectively, 260kW and 47dB.

当电子束的电流为7 A，电压为90 kV，速率比为1.0，纵向动量散度为2%时，计算得到了20%的常数驱动带宽和42%的效率，输出的峰值功率和增益分别为260 kW和47 dB。

A sample numerical design method for constant beamwidth beamformer is given. This method is easy to implement and has no restriction on array geometry and sensor patterns; Three methods for the design of broadband frequency invariant beamformer are proposed, which are the method of resampling signals received by the array, the DFT interpolation method and adaptive synthesis method, respectively. Examples and performance analyses are given for each method; A simplified linear constrained minimum variance broadband adaptive algorithm that based on DFT interpolation method is presented. Compared with conventional broadband adaptive algorithms, the presented method can reduce computation work greatly.

提出了一种简单、易于实现的恒定束宽波束形成器设计方法，该方法对阵形和阵元指向性没有任何限制；分别提出了基于阵列接收数据重采样、基于DFT插值和自适应综合的三种具有频率不变波束图的宽带波束形成器设计方法，对于每一种设计方法都给出了一个设计实例并做了性能分析；提出一种基于DFT插值的简化线性约束最小方差宽带自适应阵列算法，该方法可以大大降低自适应阵列的运算量。

This paper performs an numerical modelling on constant water flooding of water injection well arrays and production well arrays in low permeable reservoirs and analyses the factors effecting the recovery of water flooding in low permeable reservoirs, including pore structure of porous medium, oil water relative permeability curve, starting...

通过对低渗透油藏中注水井排和采油井排的定压水驱进行数值模拟，分析了低渗透油藏水驱采收率的影响因素，包括多孔介质孔隙结构、油水相对渗透率曲线、启动压力梯度、注入速度和注采井距。

Numerical results show that constant coagulation kernel has more influences on small particles than linear and quadratic coagulation kernel,whereas has less influences on big particles than linear and quadratic coagulation kernel;in the same wa...

发现常凝并核要比线性和二次方凝并核对小颗粒的影响大一些、对大颗粒的影响小一些，线性和二次方凝并核对颗粒尺度分布的时间演变影响则取决于具体情况；常冷凝核要比线性冷凝核对小颗粒的影响大一些、对大颗粒的影响小一些；连续区布朗凝并核类似于常凝并核；扩散冷凝核对颗粒尺度分布的影响界于常冷凝核和线性冷凝核之间。

Under the condition that the maximum index change at the core-cladding interface and absorption coefficient were constant, the numerical results indicated that the reflectivity of cross-mode coupling peak between LP_ 01 and LP_ 11 modes varies parabolically with the saturation length of index change.

仿真结果表明，在纤芯和包层边界的最大光致折射率变化量和纤芯吸收因子不变的情况下，随着纤芯折射率变化的饱和长度的增大，LP01和LP11模间的互耦合反射峰呈抛物线形变化，当饱和长度增大到一定值后，互耦合反射峰随饱和长度的增大而逐渐减小并最终消失；同阶LP模的自耦合反射峰随饱和长度的增大而增大。

Zhu Jialin[23]used a simple layer distribution expression based on velocity-pressure formula for the Dirichlet problem of Stokes equation with a Galerkin boundary element method and presented some numerical examples calculated by constant boundary element.

祝家麟从速度-压力公式出发，利用单层位势表示定常Stokes 方程Dirichlet 问题的解，用Galerkin 边界元法求解，并用常单元给出数值算例。

In the actual application systems of measurement, a transient process is created in a RL circuit, and then the frequency and time constant of RL circuits can be accurately estimated using numerical differentiation methods.

深入研究和分析了具有电感和电阻的电流互感器和电压互感器的等值电路，在实际测量应用中人为地造成一个RL电路的暂态过程，采用数字微分算法能够快速准确地算出RL电路的频率和时间常数，进而计算出电流互感器和电压互感器的角差。

The symplectic preserving property of the numerical methods was guaranteed by the canonical transformation, and the energy in the integration time can be adjusted to be constant by changing the parametric variable.

正则变换保证了数值积分的保辛性质，而通过调整引入的〖HT5"H〗参变量〖HT5"SS〗可保证能量在积分格点上守恒。

The Luneburg lens antenna is composed of a series of concentric shells of constant permittivity. Considering the complexity of numerical calculation, this paper presents a closed-form approach, which combines the spherical vector wave method and the reciprocity theorem.

摘要伦伯透镜是一种球形分层介质天线，考虑到数值计算的复杂性，本文提出用矢量球面波理论和互易原理相结合，分析其性能。

Physical reality can be seen as grounded in the numerical values of a handful of dimensionless constants, the best known of which are the fine structure constant and the ratio of the rest mass of the proton to the electron.

自然实在被视为基于少数无量纲常数的数值，其中最有名的常数是"精细结构常数"和"质子与电子静止质量的比率"。

But GST= 0.156, Nm=1. 588. As a result, the foundation of Youyongchi Avicennia marina population was the result of the migration of hypocotyles and human factors.

这项工作可以为海岸防护林中新引进种类的判定以及为研究种群建立者效应方法的确定提供科学依据。

The two-dimensional CDRC-ADI-FDTD update equations for collision unmagnetized plasma are induced. The unconditional stability of the CDRC-ADI-FDTD formulation for collision unmagnetized plasma is obtained by the examples.

推导了碰撞非磁化等离子体中的二维CDRC-ADI-FDTD迭代公式，并用算例验证了碰撞非磁化等离子体CDRC-ADI-FDTD算法也是无条件稳定的。