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Wireless environmental monitoring system for transformer substation based on acoustic sensor

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High Technology Letters 2012年第4期18卷 394-400页

作者：朱昌平 Huang Yon.gliang shan minglei Jiangsu Key Laboratory of Power Transmission and Distribution Equipment Technology Hohai University Changzhou 213022 P. R. China

In this paper, an indoor environmental monitoring solution is proposed for the transformer sub- station system by using the ZigBee technology. It mainly analyzes the principle of sulfur hexafluoride sensor based on the acoustic method and puts forward a difference data processing method of single- channel and temperature compensation point at power consumption issues for sensor detection. The method not only reduces the sensor power consumption, but also ensures the accuracy and extends the lifetime of wireless sensor nodes effectively. This paper also analyzes the design of the base sta- tion mode, and demonstrates the running processes of routers and sensors. The feasibility of the pro- posed approach has been testified and proved.

关键词： environmental monitoring acoustic sensor ZigBee wireless network CC2430

A Precise Sensor for SF_6 Based on Piezoelectric Ultrasound

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稀有金属材料与工程 2006年第A03期35卷 157-158页

作者： Changping Zhu minglei shan Hongping Zhang Xiaohua Zhang Peng Zhen Yuanyun Tao Department of Computer ＆ Information Engineering Hohai University Changzhou 210032 China State Key Laboratory of Hydrology-water Resources And Hydraulic Engineering Hohai University Nanjing 210098 China Data Division of ZTE Corporation Nanjing 210012 China East China University of Science ＆ Technology Shanghai 200237 China

Based on piezoelectric ultrasound technology,the paper theoretically analyses the determination of gas concentration and presents a norm-contrast method,which is realized by high-speed chip CPLD (Complex programmable logic device),to determine the concentration of SF_6 accurately with air as *** is proved that this sensor can determine the concentration of SF_6 with the precision of 50μg/*** sensor is in the process of producing.

关键词： ultrasound detection gas concentration CPLD

Investigation of cavitation bubble collapse in hydrophobic concave using the pseudopotential multi-relaxation-time lattice Boltzmann method

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Chinese Physics B 2021年第4期30卷 333-341页

作者： minglei shan Yu Yang Xuemeng Zhao Qingbang Han Cheng Yao Jiangsu Key Laboratory of Power Transmission and Distribution Equipment Technology Hohai UniversityChangzhou 213022China College of Computer and Information Hohai UniversityNanjing 210000China

The interaction between cavitation bubble and solid surface is a fundamental topic which is deeply concerned for the utilization or avoidance of cavitation *** complexity of this topic is that the cavitation bubble collapse includes many extreme physical phenomena and variability of different solid surface *** the present work,the cavitation bubble collapse in hydrophobic concave is studied using the pseudopotential multi-relaxation-time lattice Boltzmann model(MRT-LB).The model is modified by involving the piecewise linear equation of state and improved forcing *** fluid-solid interaction in the model is employed to adjust the wettability of solid ***,the validity of the model is verified by comparison with experimental results and grid-independence ***,the cavitation bubble collapse in a hydrophobic concave is studied by investigating density field,pressure field,collapse time,and jet *** superimposed effect of the surface hydrophobicity and concave geometry is analyzed and explained in the framework of the pseudopotential *** study shows that the hydrophobic concave can enhance cavitation effect by decreasing cavitation threshold,accelerating collapse and increasing jet velocity.

关键词： cavitation bubble hydrophobic concave lattice Boltzmann model pseudopotential model

Study on the concentrated SF_6 quantitative intelligent ultrasonic detection system

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High Technology Letters 2010年第4期16卷 378-382页

作者：朱昌平 Bian Mangxi shan minglei Yin Dongmei Yu Hongzhen College of Information and Electrical Engineering China University of Mining and Technology Xuzhou 221008 P.R. China Department of Computer ＆ Information Engineering Hohai University Changzhou 213022 P.R. China

In order to realize on-line quantitative detection on SF6 and effective control of nlnning state of SF6 high voltage power supply system, a concentrated SF6 quantitative ultrasonic on-line deteetion system has been developed based on the actual demand of electric power system consumers. There are four major characteristics in this system. Firstly, the gas of maximum 64 detection points is transferred through the specific air path to the detection devices to he detected and analyzed, thereby the electrical lines and the complicated installation of the collectors can be avoided; secondly, the differential technique is used to shield the influence of environmental factors, which effectively improves the accuracy of the acoustic detection; thirdly, the SF6 coneentration is determined by the speed and phase in the ultrasonic wave trans- mission process, therefore there is no secondary pollution for the purely physical means; finally, the ma- ture embedded technique is applied in this system to improve its intelligence and stability.

关键词： ultrasonic detection concentrated SF6 embedded technique

Propagation dynamics of off-axis noncanonical vortices in a collimated Gaussian beam

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Chinese Physics B 2019年第3期28卷 192-196页

作者： Cheng Yin Xuefen Kan Hailang Dai minglei shan Qingbang Han Zhuangqi Cao Jiangsu Key Laboratory of Power Transmission and Distribution Equipment Technology Hohai UniversityChangzhou 213022China The State Key Laboratory on Fiber Optic Local Area Communication Networks and Advanced Optical Communication Systems Shanghai JiaoTong UniversityShanghai 200240China

It is widely accepted that an off-axis noncanonical vortex moves across the free-space diffracting Gaussian beam without rotation. But our analysis shows that the vortex swirls a while before it approaches infinite. By neglecting the divergence of the host beam, we focus on this rotation characteristics of the vortices in linear homogeneous media. For the symmetrical host beam, it is found that the vortex moves along an elliptical trajectory, while the topological charge and the angular momentum of the vortex core relative to the beam axis are conserved. For the asymmetrical host beam, the vortex trajectory is rather complicated, since the noncanonical parameter varies as the light propagates, resulting in topological charge inversion. But we find that the vortices are always confined in a rectangular area, and the rotation direction is determined by the topological charge.

关键词： noncanonical optical vortex topological charge inversion

Electric characteristic and cavitation bubble dynamics using underwater pulsed discharge

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Plasma Science and Technology 2019年第7期21卷 16-22页

作者： minglei shan Bingyan CHEN Cheng YAO Qingbang HAN Changping ZHU Yu YANG Jiangsu Key Laboratory of Power Transmission and Distribution Equipment Technology Changzhou 213022People’s Republic of China College of Internet of Things Engineering Hohai UniversityChangzhou 213022People’s Republic of China Key Laboratory of Unmanned Aerial Vehicle Development&Data Application of Anhui Higher Education Institutes Wanjiang University of TechnologyMa’anshan 243031People’s Republic of China

Underwater pulsed discharge is widely applied in medicine, machining, and material *** induced cavitation bubble and subsequent cavitation collapse are considered the major motivations behind these applications. This paper presents an underwater pulsed discharge *** experimental setup is established to induce and investigate the cavitation bubble assisted with a high-speed camera. Three aspects, including the characteristic of the discharge with different applied voltages and conductivities, the evolution of the cavitation bubble profile, and the energy efficiency of cavitation bubble inducing, are investigated, respectively. Especially, the mechanism of pre-discharge time delay in the low field intensity case is explained using the Joule heat *** results show the validity of the underwater pulsed discharger and experimental setup. The present underwater pulsed discharger is proved to be a simple, portable, and easy-to-implement device for the investigation of cavitation bubble dynamics.

关键词： underwater pulsed discharge cavitation bubble electric discharge characteristic high-speed camera

Negative Refraction at a Lossy Interface and a Bold Hypothesis via Complex Frequency

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Journal of shanghai Jiaotong university(Science) 2019年第5期24卷 545-550页

作者： YIN Cheng KAN Xuefen shan minglei CAO Zhuangqi WANG Xianping Jiangsu Key Laboratory of Power Transmission and Distribution Equipment Technology Hohai UniversityChangzhou213022JiangsuChina Department of Physics and Astronomy Shanghai Jiao Tong UniversityShanghai200240China Jiangxi Key Laboratory of Optoelectronic and Telecommunication Department of PhysicsJiangxi Normal UniversityNanchang330022China

We investigate the negative refraction effect at a planar interface of a highly absorptive material,where the direct experimental verification is difficult because of the loss-induced skin depth effect. An apparent contradiction occurs when we try to determine the group velocity direction by the method of equifrequency contours(EFCs) in detail. This contradiction forbids any physical solution to be found for negative *** conclude that this paradox is mainly caused by the definition of complex wavevector ■which is conventionally adopted in the case of complex permittivity. The complex wavevector may result in ambiguously defined optical path, which limits the application of the classical Snell’s law. We propose a bold suggestion that the complex wavevector■ should be replaced by a complex frequency■ . Therefore, the optical path can always be defined as real. The proposed hypothesis is capable of resolving the contradiction about the loss-induced negative refraction,and the obtained theoretical prediction fits well with the reported experimental results.

关键词： Drude material negative refraction anomalous dispersion complex frequency

Interface wave propagation characteristics of liquid-immersed porous cylinder

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Chinese Journal of Acoustics 2018年第2期37卷 177-190页

作者： HAN Qingbang XU Zhouchen TONG Ziwei QI Lihua WANG Peng shan minglei ZHU Changping College of IOT Engineering of Hohai University

This paper devotes to investigate the propagation characteristics of the interface wave on the liquid-immersed porous cylinder, and special emphasis is paid on the dependence of the dispersion relation on the porous media parameters. A model of liquid-immersed porous cylinder is established theoretically. Based on the elastic-dynamic theory of liquid-saturated porous solid and wave theory, the dispersion curves and transient response of open-pores and sealed-pores are simulated numerically, and their dependence on the cylinder radius and porous medium parameters are analyzed. The results show that the Stoneley-Scholte wave can be clearly distinguished with other waves in the time domain, and the Stoneley-Scholte wave dispersion relates intimately with the porosity of the porous medium and cylinder radius, whilst the permeability of the media has little effect on the dispersion property.

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Morphological analysis for thermodynamics of cavitation collapse near fractal solid wall

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Chinese Physics B 2024年第6期33卷 422-432页

作者：单鸣雷杨雨阚雪芬殷澄韩庆邦 Jiangsu Key Laboratory of Power Transmission and Distribution Equipment Technology Hohai UniversityChangzhou 213022China College of Information Science and Technology Nanjing Forestry UniversityNanjing 210000China Department of Transportation Engineering Jiangsu Shipping CollegeNantong 226000China

A fractal geometric boundary with natural wall features is introduced into a hybrid lattice-Boltzmann-method(LBM)multiphase model. The physical model of cavitation bubble collapse near the irregular geometric wall is established to study the thermodynamic characteristics of the bubble collapse. Due to the lack of periodicity, symmetry, spatial uniformity and obvious correlation in the LBM simulation of the bubble collapse near the fractal wall, the morphological analysis based on Minkowski functional is introduced into the thermodynamic investigation of cavitation bubble so as to analyze and obtain the effective information. The results show that the Minkowski functional method can employed to study the temperature information in complex physical fields hierarchically and quantitatively. The high/low temperature region of the cavitation flow is explored, and thermal effect between irregular and fractal geometric wall and cavitation bubble can be revealed. It illustrates that LBM and morphological analysis complement each other, and morphological analysis can also be used as an optional and potential tool in research field of complex multiphase flows.

关键词： lattice Boltzmann method cavitation bubble morphological analysis