查询词典 in flux

Shadow effect can not be neglected for thermal analysis of spacecraft,Accroding to the angle between solar light and antenna orbit plane and its orbit location,analytical geometry method was used for accurately calculating solar radiation heat flux distribution of reflector surfaces.To analyze the temperature field under heat flux,the formulations of net radiation flux density between two gray elements and the net flux density of gray surface under external thermal flux were deduced.Based on the characteristic of space environment,the nonlinear temperature distribution in transverse direction of reflector shell self radiation were considered,the finite element formulations were given for orthogonal material layered shell by Galerkin method.A layered element including a inner heat source layer was proposed,and the finite element formulation expressed by DOF of the inner heat source layer were put forward with temperature and heat flux boundarys between adjacent layer.

单馈反射面赋形天线是未来星载天线发展的一个重要形式，分析了基于物理光学、几何光学和几何绕射理论的理想反射面辐射场；介绍了基于几何光学的反射面天线赋形方法；针对赋形过程中辐射场的快速分析要求，比较分析了基于物理光学的Fourier-Bessel和Jacobi-Bessel级数展开方法以及GB展开分析方法；利用GB展开快速分析方法在20GHz频率下对0.6m口径的天线进行赋形分析，实现中国大陆的30dB增益覆盖，通过数值计算研究了固定增益期望下的口径尺寸随频率的变化，以及频率为20GHz的不同尺寸天线赋形后的覆盖目标区域最大增益的变化情况。

Results from the experiment on an EHD experiment bench show that condensation heat transfer in a horizontal tube responds strongly to the EHD technique; the effect is greater for lower heat flux but lesser for higher heat flux; the enhancement coefficient is proportional to the exerted voltage for a constant heat flux and reaches as high as 156% under the conditions described in this paper.

在电流体力学强化传热试验台上进行了水平管内凝结传热的强化试验研究，结果表明，EHD技术对水平管内的凝结传热有明显的强化效果；低热流密度时，强化效果较好，增大热流密度时，强化效果减弱；热流密度维持不变时，强化系数随强化电压的升高而增大；在本试验条件下，对凝结传热的最大强化系数为 1 5 6%。

In order to implement the algorithm, a linearization method is applied in an extremely short sampling cycle to calculate the increments of torque and flux magnitude, to derive the linear equation between the desired stator flux linkage vector increment angle and the increments of torque and flux magnitude, to derive the stator voltage vector reference and to determine the next position of the stator flux linkage vector.

算法的实现运用了线性化的方法，在一个极小的采样周期内，计算出转矩增量和磁通增量，以此推导出所需的定子磁链增量角与转矩增量及磁通增量两者之间的线性方程，进一步导出所需的定子电压矢量，并确定新的定子磁链位置。

In this system,the VVVF(variable voltage variable frequency) control method based on magnetic flux trajectory is applied.In the system,it is the target for the magnetic flux linkage polygon to be greatly approximate to the ideal magnetic flux circle.Considering such limitations as the low speed torque ripple,high speed real time and the working frequency of switching element,through the subsection synchronization control method by applying different numbers of magnetic flux linkage polygon for different frequency range,the perfect precision specifications for speed can be obtained.

系统采用基于磁通轨迹法的他控式变频调速方案，以磁链多边形尽量逼近理想磁通圆为目标，并考虑低速转矩脉动、高速实时性和开关元件的工作频率限制等约束条件，通过采用分段同步控制方式，在不同的频段采用不同的磁链多边形边数，使系统获得了优异的转速精度指标。

ABSTRACT Aiming at problems of trans-vector controller in a vehicle-carried induction motor such as variable rotor and stator resistance following motor temperature, and their inductance varying with flux saturation degrees. Firstly, CSI and VSI are introduced, for CSI, it can hold the advantages both FOC and DTC using stator flux directional, PI parameter and simulation are also introduced. Secondly, equations of IM in the synchronous rotary frame and its static counterpart, as figuring in the saturation condition of magnetic field, are dealt in this paper and the simulation results are presented. Thereafter, the parameter designing of PI trans-vector controller is processed, which features the non-linear model. In practical realization, as neglecting the dynamical change of motor inductance, this paper employs online modification of inductance parameters, according to the flux saturation, then transforms the non-linear equations into linear ones, and so compacts the structure of controller. Thirdly, in view of the maximum torque output is extraordinary requisite when Electrical Vehicle start up, accelerate, and overtake, this paper issues the maximum torque when both inverter and battery capacity is corporeally definite. Fourthly, on-line differentiating and analyzing both rotor's time constants and its flux by using the expanding order reduction and discrete Kalman filter equation are fathomed, in order to realize high-performance trans-vector algorithm, and also the simulation results are presented. Fifthly, the close-loop regenerative brake system, when the EV's torque is set constant, is deduced; at the same time, unification of electric drive model and brake model is executed. Combined with maximum charge current demands, the mathematical model for online yielding torque as a demand.

本论文针对车载异步电机在矢量控制器所遇到的问题：定转子电阻随温度变化及随电机饱和程度变化的转子电感及定子电感而影响电机调速性能提出一套完整的解决方案：分析了电流型逆变器和电压型逆变器在实现矢量控制时控制器参数的计算，分析出对于电流型逆变器在采用定子磁场定向时，其性能同时具有矢量控制和直接转矩控制两者的优势，并对电压型逆变器在转子磁场定向下的模型进行了仿真研究；建立异步电机非线性模型，推导出考虑磁饱和时异步电机在同步旋转坐标系及静止坐标系下的方程，并做出了仿真结果，建立异步电机在非线性模型下的矢量控制调节器的PI参数设计，在实际应用中，若忽略电机电感的动态变化，可以根据当前的磁路饱和状态而在线修正电感参数，从而将非线性方程线性化，降低控制器的复杂度；考虑到电动汽车在起动和加速超车时需要电机有最大转矩输出，本文讨论在逆变器容量一定和电池供电能力有限的情况下电机最大转矩输出问题；推导了异步电机扩展降阶、离散卡尔曼滤波方程在线辨识转子时间常数和转子磁通，用于实现高性能的矢量控制算法，并给出了仿真结果；推导出了电动汽车恒转矩给定的闭环回馈制动系统，实现了电动控制模型和制动模型的统一，而且结合铅酸电池最大充电电流的要求，为制动转矩在线给定建立了数学模型；设计了基于双DSP系统的高性能矢量控制器软硬件框图，并以大量实验数据说明矢量控制在电动汽车应用的实际应用状况。

When the gas flux is constant, the ratio of reduced resistance is improved with the increase of the water stream velocity. However, the relationship between the gas flux and the ratio of reduced resistance is more complex. When the water stream velocity is constant, if the gas flux is small in contrast, the effectiveness of reduced resistance is not obvious. But when the gas flux increased, the jetted gas will form """"archform"""" which will augment the shape resistance. In this condition, resistance could not be reduced and could even be increased, if the gas flux continues to be increased. So that there needs setting a baffle called step, which introduces the jetted gas into the turbulence boundary layer. In this case, the shape resistance may be fairly great. Besides, the waterline of model has also some effect on the ratio of reduced resistance, which acts on the size of wave. If waterline is deep, the wave could not affect the deployment of microbubble layer, so there is almost no effect on ratio of reduced resistance. However, the wave would affect distributing of microbubble layer under the model so that the gas could leak out from the two sides of model and directly affect the ratio of reduce resistance if the waterline is very small. Whether installing the dashplate or not has also the great influence on the effectiveness the ratio of reduced resistance. From the results of experiment, conclusion is that adding dashplate will greatly improve the effectiveness of reduced resistance.

当喷气量一定时，水流速度增大，减阻率提高；喷气量与减阻率之间的关系比较复杂，速度一定时，如果喷气量较小，减阻效果就比较差，但当喷气量增大的话，喷射出的气体就会形成一个&拱度&，增加了船模的形状阻力，在这种情况下最好采取断阶喷气，把气体引入到湍流边界层中，在这种情况下，船模的形状阻力比较大；船模的吃水对减阻率也有一定的影响，主要表现在波浪大小上，如果吃水较深，波浪影响不到微气泡层的分布，对减阻率不会造成太大影响，如果吃水较浅，波浪就会影响到微气泡层在船模底部的覆盖情况，可能会有部分微气泡从船模两侧泄漏，这样就直接影响到了减阻效果；是否安装压浪板，对减阻率也有较大的影响，从试验结果可以看出，在船模尾部加设了压浪板时，减阻效果明显得到改善。

The result makes clear, 2 class give urban sewage plant on the molecular quantity interval that organic owner should center the dissolvability in water water in kDa, and the content of organic matter compares hydrophoby the element of content big; of organic matter measures hydrophily interval distributings different organic thing shows water to accept filter film flux and hold back rate having distinct effect, the organic matter under molecular quantity 2kDa causes accept filter film to appear water flux attenuation bigger, organic matter is held back rate is minor, the organic matter that amounts to 57.2%; element to measure 10 ～ 100kDa causes accept filter film to appear water flux attenuation gentlier, organic matter is held back rate is older however highest the organic matter that amounts to 73.8%; to kiss scanty sex to differ shows water to accept filter film flux and hold back rate having distinct effect, classics is right of velar surface obstruction determine, confirm cause film to appear water flux and the main material that hold back rate change to be hydrophoby material, and the change that hydrophily material causes is minor.

结果表明，城市污水厂二级出水水中的溶解性有机物主要集中在kDa的分子量区间上，且疏水性有机物的含量比亲水性有机物的含量大；分子量区间分布不同的有机物对纳滤膜透水通量和截留率有着不同的影响，分子量2kDa以下的有机物引起纳滤膜透水通量衰减较大，有机物截留率较小，达57.2%；分子量10～100kDa的有机物引起纳滤膜透水通量衰减较平缓，有机物截留率却较大最高达73.8%；亲疏性不同的有机物对纳滤膜透水通量和截留率有着不同的影响，经对膜表面阻力的测定，证实引起膜透水通量和截留率变化的主要物质为疏水性物质，而亲水性物质引起的变化较小。

Plainly, Chinese policy is in flux as it grapples with the political, social, religious and ethnic complexities of getting its raw materials out of Africa.

很明了，中国的政策在不断变化为应对盘根错节的政治、社会、宗教以及种族问题的复杂性以从非洲获取资源。

The setting was fuzzy and constantly in flux—it morphed from misty forest to cloud-covered city to arctic night—because Edward was keeping the location of our honeymoon a secret to surprise me.

周围环境有些模糊且在持续地变幻——雾气弥漫的森林到重云叠嶂的城市，又到北极圈之夜——因为爱德华不向我透露关于我们蜜月旅行地步的消息，想要给我个惊喜。

The magnetic intensity of the applied magnetic force on a ferromagnetic material denoted by the term H measured in oersteds; b. The magnetic inducition or flux density as the flux per unit area normal to the direction of the flux ,denoted by B and measured in gauss; c. The magnetic permeability establishes the relation between magnetic induction and magnetizing force expressed as B/H =u; d.Residual magnetism or remanent magnetism which remains in the casting after the magnetizing force has been removed .

磁场强度的应用磁力就一铁磁材料标注由任期h来衡量， oersteds ；乙磁inducition或磁通密度为通量每单位面积正常的方向通量，标注由B和衡量在高斯；长该磁导建立的关系磁感应强度和磁化力表示的B /为H = u ； d.residual磁性或剩余磁性，这仍然是在铸造后，磁化部队已被删除。

In the negative and interrogative forms, of course, this is identical to the non-emphatic forms.

。但是，在否定句或疑问句里，这种带有"do"的方法表达的效果却没有什么强调的意思。

Go down on one's knees;kneel down

屈膝跪下。。。下跪祈祷