超声波频率

This thesis has discussed the theory of measuring distance in ultrasonic, which include ultrasonic shaking transmit velocity, central frequency, angle of launch control, measure distance, dynamic measure and so on. According to character of wave shape output by circuit, this thesis has designed an efficient way to diminish noise that enables precision of the ultrasonic sensor to 0.2%.

论文详细论述了超声波测距的基本理论，包括超声波震动传播速度、中心频率、发射角控制、发射能量、检测距离、动态检测等；并根据电路输出波形特征设计了有效的降噪方法，使超声波传感器的精度达到了0.2%，然后对降噪后的信号进行了标定。

Based on the principle of ultrasonic cleaning, the working process of the ultrasonic cleaning machine was analyzed including control circuit, driver circuit, frequency tracking,impedance matching and software design.

依据超声波清洗原理，分析了超声波清洗机的工作过程，对超声波清洗机的控制电路、驱动电路、频率自动跟踪技术、阻抗匹配及系统软件设计方法进行了详细介绍。

But there are vocal mimics too, like a palatable species of tiger moth that deters bats by parodying the ultrasonic clicks of a toxic moth the bats detest, or like the greater racket-tailed drongo of Sri Lanka, which mimics the calls of other birds to drum up a mixed-species flock in which the drongos can more safely and efficiently forage.

但是也有针对声音的欺骗术，比如有一种自身美味无比的灯蛾会很搞笑地模仿一种令蝙蝠厌恶的毒性飞蛾的超声波频率，藉此逃避被吞吃的命运；还有一种长着像火箭似的尾巴的伊斯兰卡燕卷尾会模仿其他鸟类的叫声，招揽来各式各样的鸟群，它们身处其中会更加安全而且掠夺食物也有效率得多。

Company Profile Beijing Xinyu win equipment limited liability company operating mainly in the production and domestic and international advanced testing equipment, instrumentation, and diagnostic tools, as well as introduce advanced test, measurement of new technology for operating purposes. A: electrical fire, building fire detection and public safety facilities, equipment detectors B: lightning protection, lightning protection device detection equipment, mine detection device safety box C: Fire Fire Safety Inspection and Testing equipment, and investigate the cause of the fire equipment, police station fire alarm Services and equipment D: fire inspection and fire investigation equipment boxes, fire investigation kits, fire detection equipment to determine the scene Product E: Fire Engineering Detect boxes, cartons Detect building fire service installations, fire detection electrical box F: Airport Fire fire inspection equipment, subway Fire Safety Detect Box G: boilers, pressure vessels and special equipment, elevator equipment Detect H: Victoria seized power telecommunications equipment boxes, mechanical state patrol boxes I: Detect safety boxes, traffic accident investigation boxes, property management Detected me J: Public environmental hygiene Detect boxes, boxes of food safety at the scene detection, occupational health care at the scene Detect boxes, cartons Detect Radiological Protection at the scene, the situation of sanitation and disinfection Detected me, health production supervisor at the scene seized me K: Ultrasonic leak detector, ultrasonic spectrum analyzer, ultrasonic full-function fault detection system L: fire using infra-red thermal imaging, infrared imaging system for industrial use, the security-type infra-red thermal imaging M: Energy Conservation Supervision and Testing Instruments instrument N: Private Product: 3 1/2- 8 1 / 2 handheld / desktop Digital Multimeter, cross-DC clamp level pressure ammeter, temperature gauges, tachometer, digital megohm table, grounding resistance tester, desktop multimeter, digital frequency meter smart, figure synthesis / function signal generator, desktop digital electric bridge, oscilloscopes, infrared thermometer, vibrometer, digital DC regulated power supply, 5 1 / 2 hand-held multi-function calibrator field process instrumentation. O: agent Products:, infrared thermometer, infrared, ultrasonic full-function fault leakage / discharge detection device, flammable / toxic gas detector, harmonic power quality analyzer, portable ultrasonic flowmeter, insulation / Ground Resistance Tester, temperature, current / voltage, the process of signal, thermal resistance / thermocouple, pressure, loop calibrator, such as electronics, telecommunications, electricity, petroleum chemical industry, safety inspection, steel smelting, public environmental protection, fire detection Secret rescue, fire detection equipment, special equipment testing, military field equipment dedicated monitoring equipment and tools.

公司简介北京新宇胜利仪器有限责任公司主要以生产和经营国际，国内先进的检测仪器仪表和设备诊断工具以及介绍先进的测试，测量新技术为经营宗旨。A：消防电气、建筑消防设施检测和公共安全侦检仪器设备B：防雷、避雷装置检测仪器设备、防雷装置安全检测箱C：消防防火监督检测装备、火灾原因调查装备、公安派出所消防警务装备D：防火检查与火灾勘查仪器箱、火灾勘查工具箱、消防产品现场判定检测仪器E：消防工程检测箱、建筑消防设施检测箱、消防电气检测箱F：机场消防防火检查仪器设备、地铁消防安全检测箱G：锅炉、压力容器和特种设备、电梯检测仪器H：电信电源维检仪器箱、机械状态巡检箱I：交通安全检测箱、交通事故勘查箱、物业管理检测箱J：公共卫生环境检测箱、食品安全现场检测箱、职业健康监护现场检测箱、放射防护现场检测箱、卫生消毒状况检测箱、健康品生产现场监检箱K：超声波泄漏检测仪、超声波频谱分析仪、超声波全功能故障检测系统L：消防用红外热像仪、工业用红外热像仪、本安型红外热像仪M：节能监督检测仪器仪表工具N ：自有产品：3 1/2-8 1/2位手持/台式数字多用表，交、直流钳形高低、压电流表，温度仪表，转速表，数字兆欧表，接地电阻测试仪，台式多用表，数字智能频率计，数字合成/函数信号发生器，台式数字电桥，示波器，红外测温仪，测振仪，数字直流稳压电源，5 1/2位手持式多功能现场过程仪表校验仪。O：代理产品：，红外测温仪，红外热像仪，超声波全功能故障泄漏/放电侦测仪，可燃/有毒气体检测仪，电力质量谐波分析仪，便携式超声波流量计，绝缘/接地电阻测试仪，温度、电流/电压、过程信号、热电阻/热电偶、压力、回路校验仪等电子、通讯、电力、石油化工、安全检查、钢冶、公共环保、消防特勤侦检救援、消防检测设备、特种设备检测、军事领域的专用仪器监测设备与工具。

This paper finds that the treatment efficiency of ultrasound wave at combined frequencies of low and high excels other fashion ultrasound wave. The combined frequencies ultrasound wave with 28 kHz and 840 kHz can compensate others trough each other and eliminate stationary wave and can make furthest effect of cavitate in liquid anywhere.

3本文从理论分析及计算机模拟超声波波形传播得出低、高频搭配的超声波对印染废水的处理效果远远高于其他方式。28kHz和840kHz频率超声波能够相互补偿对方的波谷，消除驻波，使液体各处所受超声波辐射均匀且声压均最强。

Changes in Xc for different pulp cellulose fibers are not the same during the ultrasonic treatment. Crystallization and decrystallization may both exist during the treatment at the conditions of lower-intensity ultrasonic wave. After treatment with ultrasonic Xc of MBKP cellulose is decreased and that of EBKP is increased. The changes of Xc of different pulp cellulose are more closely correlated to the fibers' morphology size and the cavitation state. The maximum Xc of 84% is obtained when BEKP cellulose is treated under the conditions of ultrasonic frequency f=23-25kHz, power=400w, and treatment time t=720s.

不同原料来源的纤维素纤维，由于形态尺寸和超分子结构的差异，经超声波处理后超分子结构表现出不同的变化规律；超声波处理过程中，结晶和消晶两种作用同时存在；超声波功率对纤维素的结晶度有较大的影响，对晶体尺寸有一定程度的影响，但结晶度Xc与超声功率没有线性关系；在频率为23-25kHz，功率为400W条件下，对桉木漂白浆纤维进行超声波处理，可获得高结晶度（84%）的纤维素样品。

In this paper,the different frequency ultrasonic and sweep frequency ultrasonic is used to degum ramie,which shows that the effect of sweep frequency ultrasonic is perfect.

文章通过采用不同频率的超声波和扫频式超声波对苎麻脱胶的对比试验，说明了扫频式超声波对苎麻脱胶的优势，并通过分析苎麻原麻的结构和超声波脱胶特性对扫频式超声波这一优势加以解释。

In this paper,The necessity of frequency tracking in ultrasonic cleaning equipmens is discussed.Based on a introduction on the principle of the mian circuit of the ultrasonic power supply for cleaning equipmens and the principle of PLL ,the output frequency of 74HC4046 is changed by a singlechip measuring the phase difference between volage and current.

本文讨论了超声波清洗机中自动频率跟踪的必要性，在介绍超声波清洗机的主电路原理、PLL锁相环原理的基础上，利用单片机检测超声电源负载的电流、电压的相位差，来改变74HC4046 的输出频率，完成了变步长频率跟踪软件设计。

In this paper,the necessity of frequency tracking in ultrasonic cleaning equipmens is discussed.Based on introduction on the principle of the mian circuit of the ultrasonic power supply for cleaning equipmens and the principle of PLL,the output frequency of 74HC4046 is changed by a single chip measuring the phase difference between volage and current.The software of adaptive tracking technique with varied frequency steps is completed.

讨论了超声波清洗机中自动频率跟踪的必要性，在介绍超声波清洗机的主电路原理、PLL锁相环原理的基础上，利用单片机检测超声电源负载的电流、电压的相位差，从而改变74HC4046 的输出频率，完成了变步长频率跟踪软件设计。

But there are vocal mimics too, like a palatable species of tiger moth that deters bats by parodying the ultrasonic clicks of a toxic moth the bats detest, or like the greater racket-tailed drongo of Sri Lanka, which mimics the calls of other birds to drum up a mixed-species flock in which the drongos can more safely and efficiently forage.

但是也有针对声音的欺骗术，比如有一种自身美味无比的灯蛾会很搞笑地模仿一种令蝙蝠厌恶的毒性飞蛾的超声波频率，藉此逃避被吞吃的命运；还有一种长着像火箭似的尾巴的伊斯兰卡燕卷尾（反正是一种鸟，我以前没听到过，长相如何请参见wiki，点这里。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。