沈中华
个性化签名
- 姓名:沈中华
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学术头衔:
博士生导师, 教育部“新世纪优秀人才支持计划”入选者
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学科领域:
数理科学
- 研究兴趣:
沈中华,女,1973年10月生,博士,教授,博士生导师。1999年4月在南京理工大学应用物理系光学工程专业获博士学位,1999年4月至2001年4月在南京大学电子科学与工程系声学研究所博士后流动站工作,出站后至今在南京理工大学理学院信息物理与工程系从事教学与科研工作,其中2004年获德国“克虏伯”青年学者奖学金在德国海德堡大学作访问学者,此后多次受邀到该校作短期访问及合作研究。承担本科生“大学物理”和“信息光学”课程和研究生“激光超声原理及技术”和“计算物理”课程教学,发表教学论文多篇,主持完成国家和省自然科学基金项目各一项,为主参加完成兵器工业部和国防科工委项目多项,曾获国家教委科技进步奖三等奖一项和兵器工业部科学技术进步二等奖一项。在国内外的核心学术刊物和国际会议上发表学术论文五十余篇,目前为多家国内一级期刊及国外期刊的特聘审稿专家或审稿人。2003年获江苏省普通高等学校“青蓝工程”优秀青年骨干教师,2005年获南京理工大学董事会优秀后备学科带头人奖。
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1335
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成果阅读
240
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成果数
7
【期刊论文】Mechanical properties of nanocrystalline diamond films
沈中华, Z. H. Shena and P. Hessb J. P. Huang, Y. C. Lin, and K. H. Chen L. C. Chen S. T. Lin
JOURNAL OF APPLIED PHYSICS 99, 124302 2006 ,-0001,():
-1年11月30日
Nanocrystalline diamond _NCD_ films with thicknesses in the range of 0.12–1.5 _m were deposited on silicon substrates in CH4/H2/O2 gas mixtures by microwave plasma-enhanced chemical vapor deposition. The morphology and structure of these NCD films were analyzed by field-emission scanning electron microscopy, x-ray diffraction [XRD], and ultraviolet-Raman spectroscopy. The lower limit of the grain size in the NCD films was estimated to be 10 nm from the XRD measurements. These grains are embedded in a columnar-type structure. The elastic and mechanical properties of the NCD films were determined by measuring the dispersion of laser-induced surface acoustic waves. The densities were in the range of 3.41±0.11g/cm3 and Young's moduli varied between 674±34 and 953±48 GPa, depending on the growth time and deposition conditions. It is concluded that oxygen may have a significant positive effect on the elastic properties of NCD films. The growth rate decreases sharply for an oxygen content in the source gas in excess of about 4%.
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沈中华, Z. H. Shen a, , P. Hess a, *, J. P. Huang b, Y. C. Lin b, K. H. Chen b
Ultrasonics 44(2006)e1229-e1232,-0001,():
-1年11月30日
Laser-induced surface acoustic waves (SAWs) were used to study the influence of oxygen on the elastic properties of nanocrystalline diamond films. A series of samples was grown by chemical vapor deposition (CVD) on the (100) plane of p-type silicon for 3 h under different O2/(CH4+H2) flow ratios from 0% to 8%. The elastic properties of these nanocrystalline diamond films were determined from the SAW dispersion curves. The maximum frequency realized was about 310 MHz in wideband SAW experiments and about 700 MHz using a narrowband mask method with several higher harmonics. It was found that the densities of all samples were surprisingly high, approaching the ideal value of diamond, whereas the Young's modulus increased from 700 to 950 GPa with the addition of oxygen. It is concluded that oxygen has a significant positive effect on the elastic properties of nanocrystalline diamond.
Laser-induced surface acoustic waves, Nanocrystalline diamond film, Elastic properties
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【期刊论文】Simulation of leaky Rayleigh wave at air–solid cylindrical interfacesby finite element method
沈中华, Yan Zhao, Zhonghua Shen *, Jian Lu, Xiaowu Ni
Ultrasonics 44(2006)e1169-e1172,-0001,():
-1年11月30日
The finite element method is used to simulate the laser-excited leaky Rayleigh wave at air–solid cylindrical interfaces. A whole arithmetic of fluid–solid interaction is presented, which includes a coupling matrix that describing the process of the interaction between fluid and solid, the Arbitrary Lagrangian–Eulerian (ALE) formulation for treating the variation of fluid domain, which results from the Rayleigh wave propagating on the cylindrical interface, etc. Typical calculation is executed and the results show that the polarity of leaky Rayleigh waveform gradually changes as it propagates on the air–solid cylindrical interface.
Air–solid cylindrical interface, Finite element method, Leaky Rayleigh wave
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【期刊论文】Determination of elastic properties of a film-substrate systemby using the neural networks
沈中华, Baiqiang Xu Zhonghua Shena) and Xiaowu Ni Jijun Wang Jianfei Guan and Jian Lu
APPLIED PHYSICS LETTERS VOLUME 85, NUMBER 25 20 DECEMBER 2004,-0001,():
-1年11月30日
An inverse method based on artificial neural network (ANN) is presented to determine the elastic properties of films from laser-genrated surface waves. The surface displacement responses are used as the inputs for the ANN model; the outputs of the ANN are the Young's modulus, density, Poisson's ratio, and thickness of the film. The finite element method is used to calculate the surface displacement responses in a film-substrate system. Levenberg Marquardt algorithm is used as numerical optimization to speed up the training process for the ANN model. In this method, the materials parameters are not recovered from the dispersion curves but rather directly from the transient surface displacement. We have also found that this procedure is very efficient for determining the materials parameters of layered systems.
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【期刊论文】Simulation of laser-generated ultrasonic waves in layered plates
沈中华, A. Cheng, T. W. Murray, a) and J. D. Achenbach
J. Acoust. Soc. Am. 110 (2), Aug. 2001,-0001,():
-1年11月30日
A model is presented for the pulsed laser generation of ultrasound in isotropic layered plates. The stresses and displacements of the plate have been formulated in the Hankel and Laplace transform domains using the Thompson transfer matrix approach. The time domain response has been obtained by numerically inverting the transforms. Several numerical results are presented showing the normal surface displacement in the following configurations: single-layer film on a semi-infinite substrate, two layers on a semi-infinite substrate, and three-layer plates. The model provides a useful tool for the determination of which modes are generated by a laser source in a layered system. It can also be used to determine how sensitive the modes are to small changes in density, thickness, or elastic properties of the layers and to help in the selection of experimental parameters laser spot size, pulse length, and source to receiver distance! for optimal sensitivity.
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沈中华, Z. H. Shena, *, B. Q. Xua, b, X.W. Nia, J. Lua, S. Y. Zhangc
Optics & Laser Technology 36(2004)139-143,-0001,():
-1年11月30日
The generation of ultrasound in 5lm–substrate system by a laser line source is studied in the case of ablation mechanism, which can be realized by adding a liquid layer at the excitation point. The time domain displacement can be yielded by the numerical jointed inversed Laplace–Fourier transformation technique. The typical surface acoustic waves (SAW) of two layer structures, slow 5lm on fast substrate and fast 5lmon slow substrate, are obtained and the e;ect of the propagation distance and the thickness of the 5lmon the SAW are given.
Laser, SAW, Two-layer structure
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【期刊论文】Finite element model of laser-generated surface acoustic wavesin coating-substrate system
沈中华, Baiqiang Xu Zhonghua Shena) Xiaowu Ni, and Jian Lu Yawei Wang
JOURNAL OF APPLIED PHYSICS VOLUME 95, NUMBER 4 15 FEBRUARY 2004,-0001,():
-1年11月30日
The generation of ultrasound in coating-substrate systems subjected to laser beam illumination has been studied quantitatively by using the finite element method. Taking into account the temperature dependence of material properties, the transient temperature and temperature gradient field can be obtained in different coating-substrate systems. According to the thermoelastic theory, these temperature gradient fields are taken as bulk sources to generate ultrasound in coating-substrate systems. The typical surface acoustic waves (SAWs) in systems, a slow coating on a fast substrate and a fast coating on a slow substrate, are obtained. The influence of the propagation distance and the coating thickness on the SAWs is analyzed. © 2004 American Institute of Physics.
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