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Generation of breathing solitons in the propagation and interactions of Airy–Gaussian beams in a cubic–quintic nonlinear medium

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Chinese Physics B 2018年第11期27卷 528-533页

作者： Weijun Chen Ying Ju Chunyang Liu Liankai Wang Keqing Lu School of Science Changchun University of Science and Technology Changchun 130022 China institute of electronics and Information engineering Tianjin Polytechnic University Tianjin 300387 China

Using the split-step Fourier transform method, we numerically investigate the generation of breathing solitons in the propagation and interactions of Airy–Gaussian（AiG） beams in a cubic–quintic nonlinear medium in one transverse dimension. We show that the propagation of single AiG beams can generate stable breathing solitons that do not accelerate within a certain initial power range. The propagation direction of these breathing solitons can be controlled by introducing a launch angle to the incident AiG beams. When two AiG beams accelerated in opposite directions interact with each other,different breathing solitons and soliton pairs are observed by adjusting the phase shift, the beam interval, the amplitudes,and the light field distribution of the initial AiG beams.

关键词： cubic-quintic nonlinear medium Airy-Gaussian beams propagation and interactions breathing solitons

Excitation and Detection of Shear Horizontal Waves with Electromagnetic Acoustic Transducers for Nondestructive Testing of Plates

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Chinese Journal of Mechanical engineering 2014年第2期27卷 428-436页

作者： MA Qingzeng JIAO Jingpin HU Ping ZHONG Xi WU Bin HE Cunfu electric Power Research institute of Guangdong Power Grid Corporation College of Mechanical engineering and Applied electronics technology Beijing University of Technology

The fundamental shear horizontal（SH0） wave has several unique features that are attractive for long-range nondestructive testing（NDT）. By a careful design of the geometric configuration, electromagnetic acoustic transducers（EMATs） have the capability to generate a wide range of guided wave modes, such as Lamb waves and shear-horizontal（SH） waves in plates. However, the performance of EMATs is influenced by their parameters. To evaluate the performance of periodic permanent magnet（PPM） EMATs, a distributed-line-source model is developed to calculate the angular acoustic field cross-section in the far-field. Numerical analysis is conducted to investigate the performance of such EMATs with different geometric parameters, such as period and number of magnet arrays, and inner and outer coil widths. Such parameters have a great influence on the directivity of the generated SH0 waves that arises mainly in the amplitude and width of both main and side lobes. According to the numerical analysis, these parameters are optimized to obtain better directivity. Optimized PPM EMATs are designed and used for NDT of strip plates. Experimental results show that the lateral boundary of the strip plate has no perceivable influence on SHO-wave propagation, thus validating their used in NDT. The proposed model predicts the radiation pattern ofPPM EMATs, and can be used for their parameter optimization.

关键词： electromagnetic acoustic transducers shear-horizontal waves strip plate nondestructive testing

Fabrication of Ordered Micro/Nanostructures Using Probe‑Based Force‑Controlled Micromachining System

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Chinese Journal of Mechanical engineering 2022年第6期35卷 178-193页

作者： Yanquan Geng Yuzhang Wang Jianxiong Cai Jingran Zhang Yongda Yan Key Laboratory of Micro‑systems and Micro‑structures Manufacturing of Ministry of Education Harbin Institute of TechnologyHarbin 150001China Center for Precision engineering Harbin Institute of TechnologyHarbin 150001China College of Mechanical and electric engineering Changchun University of Science and TechnologyChangchun 130000China

This paper presents a probe-based force-controlled nanoindentation method to fabricate ordered micro/*** the experimental and finite element simulation approaches are employed to investigate the influence of the interval between the adjacent indentations and the rotation angle of the probe on the formed micro/*** non-contacting part between indenter and the sample material and the height of the material pile-up are two competing factors to determine the depth relationship between the adjacent *** the one array indentations,nanostructures with good depth consistency and periodicity can be formed after the depth of the indentation becoming stable,and the variation of the rotation angle results in the large difference between the morphology of the formed nanostructures at the bottom of the one array *** addition,for the indentation arrays,the nanostructures with good consistency and periodicity of the shape and depth can be generated with the spacing greater than 1μ***,Raman tests are also carried out based on the obtained ordered micro/nanostructures with Rhodamine probe *** indentation arrays with a smaller spacing lead to better the enhancement effect of the substrate,which has the potential applications in the fields of biological or chemical molecular detection.

关键词： Ordered micro/nanostructure Probe-based micromachining In-process force-controlled Indentation array Micro cutting

Measurement of the Elasticity of Biological Soft Tissue of Finite Thickness

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Chinese Physics Letters 2016年第12期33卷 96-100页

作者：周红生王彤宇徐峥程茜钱梦騄刘逍逸 College of Mechanical and electric engineering Changchun University of Science and Technology Shanghai Acoustics Laboratory Chinese Academy of Sciences institute of Acoustics Tongji University

Elasticity is of profound significance to evaluating the function of a biological soft tissue. When the elasticity of a tissue is macroscopically changed, it means that the biological function of the tissue is abnormal and some disease or injury may occur. In the present work, an elastometer is developed to measure the elasticity of biological soft tissues. The measurement is based on the indentation method and the force is measured by the bending of the cantilever. The force-indentation data of the soft tissue is experimentally measured by this elastometer and Young＇s modulus of the tissue is calculated using the Hertz-Sneddon model. For comparison, a numerical model for the indentation method is established using the finite element method. The difference between the actual modulus and the measured modulus is discussed. The effect of the thickness of the specimen on the measurement is investigated. Young＇s moduli of beef, porcine liver and porcine kidney are experimentally measured. The results indicate that our elastometer is effective in measuring Young＇s modulus of a soft tissue quantitatively.

关键词： of in is for Measurement of the Elasticity of Biological Soft Tissue of Finite Thickness

Intersubband absorption with difference-frequency generation in GaAs asymmetric quantum wells

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Chinese Physics B 2012年第8期21卷 252-257页

作者：曹小龙李忠洋姚建铨王与烨朱能念钟凯徐德刚 College of Precision Instrument and Opto-electronics engineering Institute of Laser and Opto-electronicsTianjin University Key Laboratory of Opto-electronics Information technology(Tianjin university) Ministry of Education institute of electric Power North China University of Water Resources and Electric Power

An asymmetric quantum well （AQW） is designed to emit terahertz （THz） waves by using difference frequency generation （DFG） with the structure of GaAs/Al0.2Ga0.8As/***. The characteristics of absorption coefficients are analysed under the parabolic and non-parabolic energy-band conditions in detail. We find that the absorption coefficients vary with the two pump optical intensities, and they reach the maxima when the pump wavelengths are given as λp1 = 9.70 μm and λp2 = 10.64 μm, respectively. Compared with non-parabolic conditions, the total absorption coefficient under parabolic conditions shows a blue shift, which is due to the increase in the energy difference between the ground and excited states. By adjusting the two pump optical intensities, the wave vector phase-matching condition inside the AQW is satisfied.

关键词： asymmetric quantum wells absorption coefficient THz-wave phase-matching

NEW METHOD OF REDUCING HEAT DEFORMATION OF SLIDEWAY GRINDERS

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Chinese Journal of Mechanical engineering 2007年第3期20卷 9-12页

作者： YAN Zhanhui CAO Yi YU Junyi School of Mechatronics engineering Changchun Institute of Technology Changchun 130012 China Machinery ＆ electric Equipment and Research Design institute of Jilin Chanclchun 130012 China College of Mechanical Science ＆ engineering Jilin University Changchun 130025 China

A new concept used for designing large-scale and high-precision NC slideway grinders which are called self-collimation slideway grinders is introduced to eliminate thermal deformation of them. Its principle is to make use of gravitational deformation of machine beds and their foundations automatically to compensate for thermal deformation caused by environmental temperature fluctuation and friction heat between machine tables and machine beds by decreasing longitudinal section stiffness of machine beds and foundations. By FEM analysis and application of more than 10 years, it shows that they have advantages of high precision and low cost, moreover, no constant temperature rooms are required. The linearity error of parts machined with them is less than 0.003 mm/m, and machining precision can almost keep constant for a long time.

关键词： Slidewaygrinders Heat deformation Self-collimation Flexibility

A pseudo differential Gm-C complex filter with frequency tuning for IEEE802.15.4 applications

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Journal of Semiconductors 2011年第7期32卷 89-96页

作者：程心钟伦贵杨海钢刘飞高同强 institute of electronics Chinese Academy of Sciences Graduate university of the Chinese Academy of Sciences Department of Electronic Information and electric engineering Fujian University of Technology

This paper presents a CMOS G;-C complex filter for a low-IF receiver of the IEEE802.15.4 standard.A pseudo differential OTA with reconfigurable common mode feedback and common mode feed-forward is proposed as well as the frequency tuning method based on a relaxation oscillator.A detailed analysis of non-ideality of the OTA and the frequency tuning method is *** analysis and measurement results have shown that the center frequency of the complex filter could be tuned *** chip was fabricated in a standard 0.35μm CMOS process,with a single 3.3 V power *** filter consumes 2.1 mA current,has a measured in-band group delay ripple of less than 0.16μs and an IRR larger than 28 dB at 2 MHz apart,which could meet the requirements of the IEEE802.15.4 standard.

关键词： IEEE802.15.4 standard complex filter G_m-C filter frequency tuning

A permanent magnet electron beam spread system used for a low energy electron irradiation accelerator

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Chinese Physics C 2014年第10期38卷 111-116页

作者：黄江熊永前陈德智刘开峰杨军李冬余调琴樊明武杨波 College of electrical and electronics engineering State Key Laboratory of Advanced Electromagnetic Engineering and TechnologyHuazhong University of Science and Technology China electric Power Research institute

The development of irradiation processing industry brings about various types of irradiation objects and expands the irradiation requirements for better uniformity and larger areas. This paper proposes an innovative design of a permanent magnet electron beam spread system. By clarifying its operation principles, the author verifies the feasibility of its application in irradiation accelerators for industrial use with the examples of its application in electron accelerators with energy ranging from 300 keV to 1 MeV. Based on the finite element analyses of electromagnetic fields and the charged particle dynamics, the author also conducts a simulation of electron dynamics in magnetic field on a computer. The results indicate that compared with the traditional electron beam scanning system, this system boosts the advantages of a larger spread area, non-power supply, simple structure and low cost, etc., which means it is not only suitable for the irradiation of objects with the shape of tubes, strips and panels, but can also achieve a desirable irradiation performance on irregular constructed objects of large size.

关键词： permanent magnet spread system irradiation accelerator finite element analysis beam dynamic,uniformity

An optimal torque distribution for electric vehicle based on sliding mode observer 36

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An optimal torque distribution for electric vehicle based on...