速度函数

The application of the lattice Boltzmann method in unsteady open channel flows was studied in detail in the paper. An existing lattice BGK model was mended; For the problem of negative local equilibrium and evolutionary distribution, we proposed a lattice Boltzmann model based on cell-population equilibrium, which is a direct non-negative approximation to the continuous Maxwell distribution. The model reduces the transport and collision, two basic evolution steps in the LB model, to transport of the non-equilibrium distribution.

本文系统的研究了格子Boltzmann 方法在明渠非恒定流中的应用问题，改进了一个现有的LB 模型，数值实验表明此改进是有效的；在平衡态分布函数及分布函数的非负性问题上，作者提出了一个基于单元均衡的格子Boltzmann 模型，通过直接对Maxwell 分布函数的离散化实现对速度分布函数的非负离散，这种方法将传统模型演化过程中的碰撞和输运两个步骤直接表现为粒子的输运。

Another reason is that the degree of linear independence of the variable basis functions composed by sigmoid functions decreases as the hidden nodes increasing, and this lead up to the inferior matrix condition number during learning, which forces the learning step length to decrease and the convergence speed to slow down.

一是因为未知系统复杂时需要较多的隐节点，从而学习的参数过多减慢了学习速度；另一个原因是随着隐节点数增加，由Sigmoid函数构造的可变基函数线性无关程度减弱，从而导致学习过程中矩阵条件数变差，迫使学习步长减小，收敛速度不得不减慢。

Quantifying similarity/difference between two objects plays an important role in many contexts The quality of the similarity/difference scores can be improved by considering the semantic information related to the features of objects A flexible semantic distance function called X Dist is proposed, which can utilize the semantic information to measure the difference between two objects based on a solution to the transportation problem from linear optimization With a ground distance function for single features being a metric, X Dist is also a metric This property is very useful for making searching efficient, but is not investigated in the previous research Moreover, the experimental results show X Dist can be as good as the previously studied similarity measures in nearest neighbor searching, discriminative power and computing speed

量化对象间相似性/差别的方法具有广泛的用途，利用相关的语义信息能够得到更好的量化结果提出了一个量化对象间语义差别的距离函数XDist，它基于线性优化中的运输问题模型和相关的语义信息量化两个对象之间的差别在量化特征的差别函数是度量的情况下，XDist是一个度量，在提高搜索的效率方面具有优势，弥补了以往研究的不足，而且实验初步表明，此函数在最近邻查询效果、差别分辨力和计算速度方面能与已有函数相媲美1 引言量化对象间相似性/差别的方法具有广泛的用途，例如数据挖掘中的聚类；信息检索中的相似文档查询；协同过滤中的相似用户查询；CBR中的相似案例查询集合是对象特征表示的常用结构，集合的元素是与对象特征相关的项，它们可以

Field data of pedestrian flow was collected in Chinese comprehensive passenger transport terminal—Xizhimen underground station using video recording, and then selected and analyzed by statistic analysis software SPSS. Parameters relation models for pedestrian flow on different terminal facilities were established based on data statistics. The results show that the pedestrian flow-density relation model is quadratic equation in corridor; the flow-space relation model is quadratic equation when space is below a certain value and is logarithmic equation when space is above the value; the speed-density relation model is linear equation. The models on stairs show the similar characteristics, but the eigenvalue is different.

对国内综合交通客运枢纽——北京西直门地铁站行人流数据进行视频采集，采用统计分析软件SPSS对行人流参数数据进行筛选及拟合分析，建立了不同设施的行人流参数关系曲线及函数模型，研究结果表明，水平通道处行人流量与密度呈二次函数关系、流量与空间在某一临界点两侧分别呈二次函数及对数函数关系、速度与密度呈线性关系，楼梯处与之相似但特征点数值存在差异。

In this paper,a rational approximation method of the norm of parametric speed is given,which is more effective than the polynomial approximation.

文章根据等距曲线逼近的关键在于对其参数速度模的逼近，提出了对参数速度模有理逼近的2种形式，在此基础上给出了平面Bézier曲线等距曲线的逼近函数和误差估计函数，并导出了保持法矢平移方向的代数方式的等距有理逼近算法。

The author thinks that the experimental curves measured by resonant-fluorescence excitation are the velocity distribution functions, but those measured by nonresonant fluorescence excitation are not the velocity distribution functions directly.

作者认为，共振荧光激发模式测出的就是速度分布函数，而非共振荧光激发模式测量的结果不能直接反映速度分布函数。

The results show that these functions have better unimodality, same adjusting focus range and accuracy, but the functions related with gradient are too slow to use in the numerical quasi-real time reconstruction.

结果表明，这些函数都具有较好的单峰性、一致的调焦范围和准确性，但与梯度运算相关的调焦函数运算时间太长；傅里叶频谱函数调焦速度最快，是首选的聚焦评价函数。

This paper presents several control methods for BLDC motor, and describes their fundamental principles ,advantages and disadvantages in brief. The method of speed-independent function,based on a new flux linkage function,is explained in detail. This method makes it possible to detect the rotor position over a wide speed range from near zero to high speed.

本文介绍了几种无位置传感器无刷直流电动机的转子位置检测方法，并对它们的基本原理，优缺点作了简单的说明，详细地阐述了基于一种新磁链函数之上的与速度无关的位置函数控制方法，利用这种方法从零转速到高转速的宽速度范围内能检测到转子位置。

When the reconstructed wind approachs the original one, it means the partitioning process is successful and the calculated stream function and velocity potential is accurate.

目前，对风场进行有效分解的方法是对有限区域里的流函数和速度势进行求解，然后对流函数和速度势求导得到对应的无辐散风与无旋转风。

Ultimately, we calculate steam function field, velocity field, pressure field and stress field.

最终，得到了粘弹性流体在扩张流道内流动时的速度场、流函数场、压力场和应力场以及在带横向槽流道内流动时的速度场和流函数场。

Cynanchum Lingtai apricot production in the average weight 65 grams, the brightly-colored fruit, juicy rich, sweet-sour taste, sweet from the nucleolus, when the late Qing Dynasty famous Shaanxi, Gansu provinces, the Qing imperial court Tongzhi tribute for years.

灵台生产的牛心杏平均单果重65克，果实色泽鲜艳，汁多味浓，甜酸适口，离核仁甜，清末时就驰名陕、甘两省，清同治年间曾为朝廷贡品。

Chenopodium album,Solanum nigrum, and Amaranthus retroflexus were very susceptible to the herbicides. Polygonum persicaria and Abutilon theophrasti were relatively less susceptible to the herbicides, and Lycopersicon esculentum was not susceptible to it. The relationship between reduction rates of weed biomass and PPM values of weed leaves 2,4, and 6 days after treatment was established.

供试的6种杂草对该混剂的敏感性存在显著差异：红心藜Chenopodium album、龙葵Solanum nigrum和反枝苋Amaranthus retroflexus对该混剂最敏感，ED90值分别为47.65、71.67和29.17g/hm2；春蓼Polygonum persicaria和苘麻Abutilon theophrasti敏感，ED90值分别为96.91、114.20g/hm2；而番茄不敏感。