高频率

Researched influence of frequency on characteristic of electromagnetic wave transmission in tunnels, and analyzed characteristic of electromagnetic wave transmission in circular, arches and curved tunnels by method of metal wave guide, and gives approximate formulas of attenuation rate. Main conclusions we obtain are as follows: in circular,rches tunnels, if frequency is higher, attenuation rate is smaller, it is beneficial for EM waves to transmit, in curved tunnel, higher frequency, more attenuation rate ...

研究了频率对井下电磁波传输特性的影响，采用金属波导法分析了圆形、拱形及弯曲隧道中电磁波的传输特性并给出衰减率近似公式，得出主要结论：在圆形和拱形隧道中，频率越高，衰减率越小，越有利于电磁波的传播；在弯曲隧道中，频率越高，衰减率越大，不利于电磁波的传播；通过特性曲线与井下实验数据相比较得出在900MHz左右为井下无线通信系统传输信号最佳频段。

With regard to the external Qinhuai River regulation project in Nanjing City, the inverse Gaussian distribution curve was determined as the flood level frequency curve of the river course by use of the frequency statistics technique, and the parameters λ and μ of the inverse Gaussian distribution were derived according to the current flood design standard.

结合南京市外秦淮河堤防整治工程，放弃传统的堤防潮位频率曲线线型，采用频率统计分析的方法确定了外秦淮河堤防潮位频率曲线的线型为反高斯分布；根据该堤防现行洪水设计标准推求了反高斯分布参数λ和μ。

The main content of this dissertation includes: 1. Research on the theory of ultrasonic power supply, introduce its development process. On the basis of these, fix on the scheme of medical ultrasonic low-power supply. 2. According to the principle of modularized design, divide medical ultrasonic low-power supply into four parts. They are power amplify circuit, power control circuit, frequency automatic tracking circuit and matching circuit. Separately research on their theories and design their circuits and necessary programs, especially, effectively resolve the problem tracking the supersonic vibration system with a narrow syntony frequency bandwidth and a high swing. 3. The matching experiments gain good result, and prove that medical ultrasonic low-power supply is entirely up to the mustard on intellectualization, wide band of working frequency, steady output and high efficiency.

本文工作的主要内容包括： 1、研究了超声功率电源的原理，并回顾了它的发展过程，在此基础之上确定本文医用小功率超声电源的设计方案； 2、按照模块化的设计原则，将医用小功率超声电源的设计分解为功率放大电路、功率控制电路、频率自动跟踪电路和匹配电路等四个部分，分别研究了各部分的原理，在此基础之上进行了具体的电路设计和程序设计，尤其是有效地解决了对谐振频率带宽窄振幅高的超声振动系统的频率跟踪问题； 3、通过与超声振动系统的各项配合实验，取得了很好的实验结果，验证了医用小功率超声电源完全满足智能化、工作频带宽、输出功率稳定、输出效率高的设计要求。

Originally, higher input trigger frequency or lower input frequency for Viterbi Decoder were used to meet the transitions requirements.

因原本既有的标准，都是使用较高的输入频率来达成标准内的传输率，或者使用较低的输入频率，再用内部的PLL，提供出较高的触发频率给内部的维特比解码器来达成。

The agglomerations sizes of fine particles in the fluidized bed are smaller under higher SPL. The sound waves have little effect on the agglomerations when it is under 120dB. But the agglomerations sizes will be dramatically reduced to 180μm from 720μm when the SPL is above 130dB. The umf has a minimum value at an appropriate frequency of sound and a good quality of fluidization can exist in a greater ranges of frequency of sound when the SPL is higher.

当频率高于120Hz，流化床中形成聚团尺寸随着频率的增加而增大，最小流化速度也随着频率的增加而增大，当频率低于120Hz，流化床中形成聚团尺寸随着频率的减小而增大，最小流化速度也随着频率的减小而增大；料层越高，声波的衰减越大，超细颗粒的流化效果越差，最小流化速度越大。

In view of these shortcomings, this frequency meter has made the radical innovation in the design, its merit is: Uses the core component is the advanced monolithic special-purpose frequency measurement component -- monolithic frequency meter, the integration rate is high, the volume is small, consumes the electricity province, function, has realized the frequency meter high integration and the microminiaturization; So long as the monolithic frequency meter adds on the crystal oscillator, the measuring range choice, the frequency demonstrated and so on the very few components then constitute DC to the 10MHz miniature basic frequency measurement electric circuit; But the biggest merit was this frequency meter has realized monolithic frequency meter, frequency sampling electric circuit and the monolithic microcomputer three between hardware and the software connection completely, caused the frequency measurement measuring range the choice, the frequency data survey, the sampling as well as the code frontier transformation and the data dump possible monolithic microcomputer software programming automatically to carry on, thus has realized the frequency measurement and the sampling work intellectualizes completely, causes this system already to be possible to constitute a miniature intelligence to measure rate the instrument core electric circuit independently, also might take in the large-scale automatic control or a test system intelligent subsystem.

针对这些缺点，本频率计在设计上作了根本的革新，其优点是：所用核心器件是先进的单片专用测频器件——单片频率计，集成度高，体积小，耗电省，功能强，实现了频率计的高度集成化和微型化；单片频率计只要加上晶振、量程选择、频率显示等很少量的器件即可构成一个DC至10MHz的微型基本测频电路；而最大的优点则是本频率计完全实现了单片频率计、频率采样与单片微机三者之间的硬件与软件接口，使得测频量程的选择、频率数据的测量、采样以及编码的边境转换和数据的转储均可能过单片微机的软件编程自动进行，从而实现了测频与采样工作的完全智能化，使得本系统既可独立构成一个微型智能测率仪器的核心电路，也可作为大型自动控制或测试系统中的一个智能子系统。

In view of these shortcomings this frequency meter has made the radical innovation in the design its merit is: Uses the core component is the advanced monolithic special-purpose frequency measurement component -- monolithic frequency meter the integration rate is high the volume is small consumes the electricity province function has realized the frequency meter high integration and the microminiaturization; So long as the monolithic frequency meter adds on the crystal oscillator the measuring range choice the frequency demonstrated and so on the very few components then constitute DC to the 10MHz miniature basic frequency measurement electric circuit; But the biggest merit was this frequency meter has realized monolithic frequency meter frequency sampling electric circuit and the monolithic microcomputer three between hardware and the software connection completely caused the frequency measurement measuring range the choice the frequency data survey the sampling as well as the code frontier transformation and the data dump possible monolithic microcomputer software programming automatically to carry on thus has realized the frequency measurement and the sampling work intellectualizes completely causes this system already to be possible to constitute a miniature intelligence to measure rate the instrument core electric circuit independently also might take in the large-scale automatic control or a test system intelligent subsystem.

摘要传统的测频仪器体积很大，耗能量大，主要靠手工操作，而最大的缺点是不可编程，其量程转换、数据测量、采样控制和处理等均不能通过程序指令来进行控制，无法作为一个微型智能子系统与某一大型自动控制或测试系统进行接口。针对这些缺点，本频率计再设计上作了根本的革新，其优点是：所用核心器件是先进的单片专用测频器件——单片频率计，集成度高，体积小，耗电省，功能强，实现了频率计的高度集成化和微型化；单片频率计只要加上晶振、量程选择、频率显示等很晌慰的器件即可构成一个DC至10MHz的微型基本测频电路；而最大的优点则是本频率计完全实现了单片频率计、频率采样与单片微机三者之间的硬件与软件接口，使得测频量程的选择、频率数据的测量、采样以及编码的边境转换和数据的转储均可能过单片微机的软件编程自动进行，从而实现了测频与采样工作的完全智能化，使得本系统既可独立构成一个微型智能测率仪器的核心电路，也可作为大型自动控制或测试系统中的一个智能子系统。关键词高度集成化，单片机，频率计，电路

This study investigated gene polymorphism of β_1-AR, CY2PD6, ACE and of BDKRB2 in the population of Hunan mid-region by PCR and PCR-RFLP method. The results showed that the frequencies of Ser49Ser and Arg389Arg genotype of β_1-AR gene were respectively 68.7% and 55.3%. And the allele frequencies of 49Ser and 49Gly were 83.9% and 16.1%, moreover 76.1% for 389Arg and 23.9% for 389Gly.

本研究应用PCR、PCR-RFLP方法首次对湖南中部地区403例原发性高血压患者的β_1-AR基因、CY2PD6基因、ACE和BDKRB2基因多态性的调查，结果显示：β_1-AR基因型Ser49Ser、Arg389Arg分别占68.7％、55.3％，49Ser和49Gly等位基因频率分别为83.9％、16.1％，389Arg和389Gly等位基因频率分别为76.1％、23.9％；CYP2D6等位基因频率由高到低依次为~*10、~*1、~*2、~*5，CYP2D6~*10~*10基因型频率最高，占47.4％；ACEI和D等位基因频率分别为55.8％、44.2％，基因型频率分别为Ⅱ型33.5％、ID型44.7％、DD型21.8％；BDKRB2-58T/C等位基因频率C、T分别为52.6％、47.4％，基因型频率分别为CC型24.8％、CT型55.6％、TT型19.6％。

After the cut-off frequency has been determined, the active noise-filtered system can be designed with several circuits to filter out those frequencies higher than the cut-off frequency and reserve the speech voice only. Besides, the music signals from the MP3 or a CD player can also be transmitted to the earplug system for increasing the signal noise ratio. The anxiety and tension of patients during treatments can, thus, be relaxed due to the euphonious music and toothaches of the patient might be further reduced.

本研究首先以离线的方式收集各类牙科噪音，然后将它传递到个人电脑，并使用CoolEdit及LabVIEW软体程式，分析出在牙科治疗过程中所产生之噪音的频率范围，最后透过各种比较，找出适当的截止频率，在截止频率(1KHz)被决定之后；针对该截止频率，使用主动式滤波的方式设计出相关的电路，组成主动式噪音率除系统，来滤除那些高於截止频率的噪音信号，只保留语音频率范围；此外透过mp3或cd player所播放出的音乐讯号，也可以同时被传递到耳塞系统来增加信号杂讯比，那麼当病人在治疗时，因为有这音乐可以使病人的焦虑跟紧张获得舒缓。

But there was no current modulate circuit for TDLAS system.The design of modulation circuit for tunable diode laser based on DDS has been introduced.The main idea of design is using MCU to control DDS and D/A chips,so we can get sine wave and saw tooth signals.

DDS器件采用高速数字电路和高速D/A转换技术，具备了频率转换时间短、频率分辨率高、频率稳定度高、输出信号频率和相位可快速程控切换等优点，可以实现对信号的全数字式调制。

Finally, according to market conditions and market products this article paper analyzes the trends in the development of camera technology, and designs a color night vision camera.

最后根据市场情况和市面上产品的情况分析了摄像机技术的发展趋势，并设计了一款彩色夜视摄像机。

Only person height weeds and the fierce looks stone idles were there.

只有半人深的荒草和龇牙咧嘴的神像。