查询词典 frequency conversion

Dynamic video frequency color images is the subject investigated of this algotithm.Firstly, by making the best of tinct information, the face region, of which complexion is concentrative and steady, is segmented through color space conversion. In this way, the range where faces are to be searched is reduced. Secondly, multi-template matching,mosaic image validation and geometric rule affirmance are combined to detect faces. Compared with the only one method, the false detection ratio of this multiple method is reduced further more.

本算法以动态视频流彩色图像为研究对象，首先充分利用人脸面部的颜色信息，通过色彩空间变换，将肤色相对集中与稳定的人脸面部区域分割出来，这样大大缩小了后续人脸检测的搜索范围；然后再利用多模板匹配、镶嵌图验证和几何规则确认等几种方法相结合来检测人脸，与单纯仅用一种检测方法相比较，进一步降低了该算法的误检率。

Based on the conversion of trigonometric function ,a novel real-time algorithm of reactive power similar to that of active power is presented,which reactive power is speed-ily and accurately measured by the voltage,current and frequency.

运用三角函数变换的方法，提出了一种新颖的与计算有功功率相似的电网无功功率的离散化实时算法。

Adopting discrete time-domain method to set up the mathematical model of high-voltage conversion circuit, and analyzing the influence of frequency, duty cycle, primary inductance, different turns ratio parameters how to affect high-voltage convertion circuit charging time.

采用离散时域方法建立高压转换电路数学模型，分析了高压转换电路频率、占空比、原边电感量以及匝比等设计参数对高压转换电路充电时间的影响，并进行了仿真和实验验证。

A quadrature down-conversion mixer based on this topology is designed and optimized for an ultra high frequency RFID reader.

设计并优化了一个基于共用跨导级结构的用于超高频RFID阅读器的正交下变频混频器。

In this circuit, you will simply tune to whatever frequency makes the most efficient vapour conversion.

在这条赛道，你将简单的调子，无论频率，使最有效的蒸汽转换。

Based on the previous research on the deposition of amorphous/microcrystalline silicon tandem solar cells, silane concentration for the deposition of microcrystalline bottom cell was selected to further optimize the performance for micromorph tandem solar cells using very high frequency technique. Finally, micromorph silicon tandem solar cell with 11.02%(Area=1.0cm2) initial conversion efficiency has been fabricated at a certain silane concentration and suitable light trapping structure.

采用甚高频等离子体增强化学气相沉积技术，在前期我们单室沉积的微晶硅薄膜太阳电池和非晶硅/微晶硅叠层太阳电池研究的基础上，通过对微晶硅底电池本征层硅烷浓度的优化，获得了初始效率达到11.02%（电池面积1.0cm2）的非晶硅/微晶硅叠层太阳电池。

LBO crystal was used as the frequency doubling device which has the advantages of noncritical phase matching, temperature tunability, and higher conversion efficiency. The comparison between our experiment data and theoretical predictions is reported.

依据LBO晶体的温度调谐特性，采用Ⅰ类非临界相位匹配方式，探讨了LBO的倍频工作情况，文中分别给出了Nd：YAG的两种激光波长（1064nm和1319nm）的倍频实验与理论的对比结果，实验结果与理论能较好的符合。

According to the definition and the distribution of VSR's voltage space vector, the introduction of a rule-based SVPWM current control strategy, with non-fixed switching frequency and dual hysteresis loops, that obviously improves the performance of current control. Based on two kinds of control strategies of VSR under unbalanced grid condition, the introduction of a new VSR control strategy featuring undamped-oscillation that simplifies the controller structure and effectively improves VSR's performance under unbalanced grid condition. A systematic description of the state switching in trilogic PWM signal generation of threephase CSR by using the conversion between bilogic and trilogic switching functions.

作者在如下工作的基础上对PWM整流器的一些关键问题提出了自己的研究思路、观点和方法：根据PWM整流器网侧矢量关系，直观地描述了其四象限运行的基本原理及特征；定量分析了VSR、CSR的PWM换相过程及波形特征；引入等效变压器模型并详细分析了VSR、CSR基于d—q模型的动、静态特性；提出了满足四象限有功、无功运行指标时的VSR交流侧电感设计方法；并提出了依据控制系统跟随性和抗扰性性能指标设计VSR、CSR直流侧储能元件的参数计算方法；在研究了VSR电流控制策略基础上，提出了影响VSR电流控制的几个要素，并进行了定量分析；根据VSR空间电压矢量的定义及分布，提出了基于规则控制的不定频滞环空间矢量PWM电流控制策略，并由此提出了具有双滞环特性的不定频滞环优化SVPWM电流控制策略，有效地改进了滞环PWM电流控制性能。

This paper has studied preparation of Grignard reagents under phonochemistry and optimum technologic conditions is: the power of ultrasonic is 500W and frequency is 250KHZ, having twelve energy conversion devices, water bath temperature being 20C, solvent being THF,unstirred.

本文探讨了超声波合成格利雅试剂的机理，研究了声化学法制备格利雅试剂氯化苄基镁的最佳工艺条件为：在超声波的功率为500W，频率为25KHZ，有12个换能器的条件下，水浴温度为20℃，以THF为溶剂，不搅拌。

A design and implementation method of the high speed modulation system, which adopted the new techniques of the FPGA and DAC based communication system,is presented in this paper. The effect of the key techniques of this system, such as the high speed digital signal processing for modulation, high speed based-band signal conversion, wide-band modulation, carrier suppression, high frequency and high precision system clock generation, is analyzed, and the solutions and performance analysis is also given. Finally, a high speed modulation system for space applications is implemented, can be used for high speed data transmission with QPSK, 8PSK, QAM or other kinds of digital modulation.

本论文依据正交调制原理，采用基于FPGA和DAC的设计技术，提出了一种高速、灵活的调制系统的设计方法，重点分析了系统组成的调制编码映射、基带脉冲信号转换、信号滤波、调制、系统时钟产生等关键技术环节的影响，解决了高速调制信号处理、高速数据转换、宽带调制、载波抑制、高频率高精度系统时钟的产生等关键技术问题，完成了一种适用于空间应用的高传输速率、多进制数字调制方式和调制体制灵活的数据传输调制系统的设计与实现，可在硬件设计不变的情况下，实现QPSK、8PSK和16QAM等多种调制方式的高速数据传输，QPSK调制速率达到500Mbps。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。