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林顯埈 최신의학사 1971 最新醫學 Vol.14 No.9
The author report here the clinical data of 18 cases of tonsillar cancer which verifide histopathologically during six year period (Jan. 1965-Dec. 1970) at the Dept. of Otolaryngology, S. N. U. H. . The results were as follows; 1. The histopathological classification revealed 11 cases of malignant lymphoma, 4 squamous cell carci?noma;2 undifferentiated cell carcinoma and 1 anaplastic cell carcinoma. 2. The age distribution was even and the sex ratio was almost equal in malignant lymphoma, whereas the squamous cell carcinoma was found chiefly in fifth and sixth decades and in man. 3. Most of the cases (more than 80%) complained of sore throat and more than 70% of the cases had visited the clinic within three months after onset.
균열에 의한 초음파 산란 현상의 해석해 계산 프로그램 개발
任賢準,李東厚 弘益大學校 科學技術硏究所 2000 科學技術硏究論文集 Vol.11 No.-
Analytical solutions are sought for the scattering of a plane longitudinal ultrasonic wave by a semi-infinite crack embedded in an infinite elastic medium. Stress formulation for exact solution to this problem, available from the literature, is modified and extended for displacement fields. In the formulation, the Wiener-Hopf technique and the Cagniard-de Hoop method are used to solve the mixed-boundary problem. The angular distribution of the displacement magnitude due to the diffracted longitudinal wave is obtained for various angles of the incident longitudinal wave, several characteristics of the diffracted wavefield have been observed: for example, the displacement fields are symmetric with respect to the crack faces. In order to confirm the accuracy of the formulation and program for the exact solution, the results are compared with the approximate solution obtained by the geometrical theory of diffraction. It has been found that the two solutions for the longitudinal diffracted wave agree well with each other in terms of their angular distributions. Though the exact solutions for further similar problems must be found and confirmed, the analytical solutions and the programs developed in this study will play an indispensable role in the development of a reliable ultrasonic simulator.
고체내 탄성파 전파의 수치해석을 위한 질량스프링 모델 개발
孫榮薰,任賢準 弘益大學校 科學技術硏究所 1999 科學技術硏究論文集 Vol.10 No.1
A mass-spring lattice model is used to develop a numerical analysis which can simulate the phenomena of elastic wave propagation and scattering effectively. In order to confirm the reliability of their numerical results, the consistency, convergence, stability and accuracy of the algorithms are studied using the Taylor series expansion and the von Neumann analysis. As a result, the optimum size of time step is found for a given mesh size, such that more accurate numerical solution can be obtained in high frequency regime, along with significant saving of computation time. Numerical results have been obtained for fundamental problems in ultrasonic testing such as plane waves incident on cracks. All numerical results have shown excellent agreements with analytical results, and the reflected, diffracted, head, and Rayleigh waves have been observed. An improved mass-spring lattice model is shown to produce more accurate results for surface wave propagation than the previous models.
任賢準,白은솔 弘益大學校 科學技術硏究所 2002 科學技術硏究論文集 Vol.13 No.-
As an attempt to further improve the reliability and effectiveness of ultrasonic testing (UT), a two-dimensional numerical simulator of UT is desired. Such a simulator may be established by combining the previous mass-spring lattice model (MSLM) that consists of mass-points and springs and transducer models. Models of transmitting and receiving piezoelectric transducers are introduced in this paper with some numerical results. Using the models, various problems having typical UT setups are addressed, and the computed results are discussed. The numerical results appear to be physically reasonable though they should be validated through future works.