• 대한기계학회논문집A
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• 제20권1호
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• pp.68-78
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• 1996

A study of the natural vibraion of Timoshenko beam with a laminar tear is presented. An analytic model, based on the transverse and longitudinal vibration of beams is employed to determine the natural frequencies. A specific example are given to show the effects of rotary inertia, and shear deformation on the natural frequencies of the beam with a laminar tear. the variations of matural frequencies of beam with the changes of size and location of laminar tear are plotted for several thickness ratio.

• 전기의세계
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• 제20권5호
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• pp.15-18
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• 1971

Up to now, there have been numerous investigations about the effect of diffusion on the wave propagation in gaseous plasmas, but not so much in semiconductor magnetoplasmas. However, currently, it becomes the centor of interest to work with the latter problem, and this paper deals with the dispersion equation including diffusion effect in the latter case to see how diffusion affects the equation in which diffusion term is neglected in the first place, and the analysis is based on the assumption that the plasma can be treated as a hydrodynamical fluid, since, from a macroscopic view point, the plasma interacting with a magnetic field can be considered as a magneto-hydrodynamical fluid, an electrically conducting fluid subjected to electromagnetic force, and the system is linear. The results of the relation and computation show that in the non-streaming case the diffusion terms appear in the equation as perturbation terms and the amplitude of the wave vector changes parabolically with the variation of the angular frequency and the longitudinal modes are observed.

• 대한치과의사협회지
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• 제11권4호
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• pp.277-280
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• 1973

The author observed the changes of dental arch dimensions and compared spae-maintainer group with non-space-maintainer group after primary tooth extraction. The results were as follows 1) The rate of growth of dental arch of expeirmental group in intercanine width and in inter-1st molar width was more rapid than that of the control group. 2) Arch length is almost no dimensions but it was slightly decreased in lower arch. 3) Dental arch growth and tooth eruption were stimulated by space-maintainer appliance, so it is the best way to replace a new appliance at least once a year. 4) It is thought that satisfactory conclusions in this observation must be researched successively until the mixed dentition completes.

• 경영과정보연구
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• 제5권
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• pp.161-184
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• 2000

Accounting education research addresses a wide range of topics related to students, educational processes, educational outcomes, faculty, administrative structures, and the programs and constituents of accounting education. This study examines accounting education researches for the purpose of identifying changes in this research literature and opportunities for enhancing its development. The total number of accounting articles published each year has increased. More significant is the increase in the portion of articles based on empirical research and the decrease in the portion of non-empirical articles. And the empirical studies were classified by type of study, by type of statistics used in the study, and by whether the study referred to other accounting or non-accounting literature. These analysis suggests a number of opportunities for the development of future accounting education research: (1) review relevant non-accounting literature, (2) seek empirical tests of fundamental relationships, (3) design multi-institutional and longitudinal tests, (4) provide for aptitude-treatment interactions, and (5) focus on educational outcomes.

• 대한치과교정학회지
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• 제15권1호
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• pp.23-42
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• 1985

The morphology and growth changes of the Craniofacial Complex are important in orthodontics and cephalometrics for analysis and evaluation of facial bone growth are widely used. The author analyzed the data using lateral cephalometric roentgenogram of 75 Korean male and 50 Korean females age of 6 to 10 with normal occlusion to provide informations-relative rates of facial bone growth of Korean which is to be contributed in Korean standard. The results were as follows: 1. Means, standard deviation and coefficient of variation of Korean children were obtained. 2. The item which showed significent difference between male and female was craniofacial height in absolute dimension. 9. No difference of sex was showed in increment of craniofacial height and depth. 4. Among the craniofacial depth increments, the lower facial depth dimension increased most, midfacial depth dimension increased less, and cranial depth dimension increased the least. 5. The horizontal body of mandible showed rapid growing tendency more than did the ascending ramus.

• 대한치과보철학회지
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• 제19권1호
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• pp.29-37
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• 1981

The bond strengths with ceramco porcelain were compared between precious alloy S, and non-precious alloys V.U. and R. And the changes in bond strengths of non-precious alloys with ceramco porcelain, according to surface preparations by sand blasting, longitudinal grinding, transverse grinding, and high polishing, were studied. The test specimens were prepared by firing porcelain doughnuts on the surface prepared alloy rods, and investing in dental stone. The specimens were subjected to shear loading forces. The conclusions drawn from the investigation are as follows: 1. The bond strengths with ceramco porcelain were higher in the non-precious alloys U and R, than in the precious alloy S. 2. The bond strengths were in descending order for R alloy, U alloy, V alloy, and S alloy. 3. The bond strengths were highest when the R alloy and U alloy were surface prepared by sand blasting. 4. All bond strength values were lowest when the alloy surfaces were prepared by high polishing.

• Journal of Magnetics
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• 제7권1호
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• pp.21-23
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• 2002

The magnetoimpedance of $Fe_{91.5-x}Zr_7B_xCu_1Al_{0.5}$alloys has been measured to investigate the influence of structural changes in the nanocrystallization process after thermal treatment. Annealing was performed at temperatures of $350^\circ{C}$, $450^\circ{C}$, and $550^\circ{C}$ for 1 hour in a vacuum. Ultra soft magnetic behavior was observed in the samples annealed at $550^\circ{C}$. The magnetoimpedance ratio and the longitudinal permeability ratio coincided with the softness of the magnetic properties of the thermally treated samples.

• Journal of Magnetics
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• 제14권1호
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• pp.15-17
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• 2009

The magnetostatic interaction between the two magnetic nanowires was studied by using the longitudinal magneto-optical Kerr effect (MOKE). For this purpose two magnetic nanowires having different widths (400 nm, 800 nm) were fabricated on an Si substrate with electron beam lithography and the lift-off method. Magnetic hysteresis loops measured by MOKE showed double switching behavior, corresponding to the separated switching fields of each wire. The switching field of the narrow wire was greatly affected by the separation between the two wires. Based on how the switching field changes with decreasing separation, it is concluded that the magnetostatic field of the 800-nm wire strongly affects the switching of the 400-nm wire when the separation is less than $0.5{\mu}m$.

• 설비공학논문집
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• 제21권2호
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• pp.126-130
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• 2009

The present study describes an investigation into the characteristics of combustion oscillation and its suppression instability of a silo type gas turbine combustor in commercial power plant. Combustion oscillation is occurred the combustor in near full load during operation. As a result of FFT analysis of the combustion dynamics, the frequency of the oscillation is analyzed as the 1'st longitudinal mode of acoustic resonance of the combustor. For suppress of the instability, combustion tuning with adjust of fuel valve schedule is carried out, which changes equivalent ratio of each burners. As the result, the oscillation is successfully reduced with meeting the level of NOx emission regulation.

• 한국임상수의학회지
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• 제15권1호
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• pp.174-177
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• 1998

Two 7 months old Korean native beef calves, which were suspected as ergotisms were referred to the Veterinary Teaching Hospitals Chonnam National University in February 1997. Those showed severe lameness as a result of a dry gangrene of the lower part of both hindlimbs which unilaterally were detached, tail necrosis and retarded growth. On the skin of the extremities of both hindlimbs were clearly appeared indented line, hypertropic granuloma and hemorrhage, from which were isolated gicrosp$\theta$rum gysiNㅁt. On the X-ray views of hindlimbs and the longitudinal sectioned metatarsal bones were not observed any changes of osteomyelitis except slightly increased osteophytes and soft tissue swelling. Clnical and anatomical observations were suggested that these calves were affected by the ergotism.