• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.14 no.1
• /
• pp.56-63
• /
• 2004

Exact solutions are presented for the free vibration and buckling of rectangular plates haying two opposite edges ( x=0 and a) simply supported and the other two ( y=0 and b) clamped, with the simply supported edges subjected to a linearly varying normal stress $\sigma$$_{x}$=- $N_{0}$[1-a(y/b)]/h, where h is the plate thickness. By assuming the transverse displacement ( w) to vary as sin(m$\pi$x/a), the governing partial differential equation of motion is reduced to an ordinary differential equation in y with variable coefficients. for which an exact solution is obtained as a power series (the method of Frobenius). Applying the clamped boundary conditions at y=0 and byields the frequency determinant. Buckling loads arise as the frequencies approach zero. A careful study of the convergence of the power series is made. Buckling loads are determined for loading parameters a= 0, 0.5, 1, 1.5. 2, for which a=2 is a pure in-plane bending moment. Comparisons are made with published buckling loads for a= 0, 1, 2 obtained by the method of integration of the differential equation (a=0) or the method of energy (a=1, 2). Novel results are presented for the free vibration frequencies of rectangular plates with aspect ratios a/b =0.5, 1, 2 when a=2, with load intensities $N_{0}$ / $N_{cr}$ =0, 0.5, 0.8, 0.95, 1. where $N_{cr}$ is the critical buckling load of the plate. Contour plots of buckling and free vibration mode shapes ate also shown.shown.

• Journal of Chest Surgery
• /
• v.9 no.2
• /
• pp.175-186
• /
• 1976

The cellular change of the pulmonary tuberculous lesions may be divided into two groups,exudative and proliferative form by their course and fate. In the most cases, the patients usually have very much complex type of cellular changes. Therefore, the shadows of the chest films in pulmonary tuberculosis are also much variable in nature. And Daniel said that knowledge of the pathology of tuberculosis and an appreciation of the method of progression and healing are essential to proper interpretation of the films. Author, having reviewed 33 cases of resected tuberculous lung obtained in N.M.T.H. for one year from Oct. '75 to Sep. '76 by surgical managements, classified the Pathological findings such as: 1) caseation only, 2) tuberculoma, 3) atelectatic lung 4) cavitary lesion and 5) atelectasis with cavity, and examined the relationship between the roentgenological characteristics of the chest films and the pathological process of tuberculous lesions of the resected lungs, The result were obtained as follows. (1) Tuberculoma was commonly appeared in $S_2$ segment in right and $S_6$ segment in left. (2) Atelectasis and destroyed lung were more commonly appeared in left lung than right, and their containing rate of cavity was 82%. (3) Cavities were mostly appeared in $S_1$ and $S_2$ segments of both lung and the appearance-rate of cavity on $S_6$ segment was higher in left than right. And among the cavitary lesions of the resected lung, cavity was not seen in the preoperative chest films in 22%. (4) The configuration, thickness and sharpness of the walls of cavities, which revealed the cavitary shadows in the preoperative chest films, were mostly depended on the degree of increased collagenous fiber of the wall, existence of perifocalitis, and more or less of the caseous masses on the inner surface of the cavity wall.

• The Korean Journal of Mycology
• /
• v.16 no.4
• /
• pp.235-241
• /
• 1988

This study was carried out to investigate some morphological characters of fruit bodies of Ganoderma lucidum and to classify the fungus on the bases of the genetic character. Some of the isolates of the fungus which originally have the kidney-shaped fruit bodies produced the antler-shaped fruit bodies on artificial media and the latter characters were inherited. Pattern of the pileus surface and thickness of the pileus of the fruit bodies were also considered to be hereditary. Although morphology of the pileus margin and fruiting mode of the fungus were variable among the isolates, they were greatly influenced by environment conditions. Ganoderma lucidum could be classified into two groups and four strains according to the morphology of the fruit bodies on artificial cultivation media. Electrophoretic patterns of esterase, peroxidase, leucine aminopeptidase(LAP) and proteins of fruit bodies and mycelia of Ganoderma lucidum showed high genetic variation. Isozyme patterns of esterase of the mushroom mycelia were applicable for the classification of strains of the fungus. Patterns of proteins, leucine aminopeptidase and peroxidase did not indicate any genetic relation among the fungus strains.

• Ocean and Polar Research
• /
• v.28 no.4
• /
• pp.475-484
• /
• 2006

In order to reveal the vertical variation of physical properties in deep-sea sediments, deep-sea sediment cores were collected at 78 stations using a multiple corer in the KR5 area, one of the Korea contract areas for manganese nodule exploration, located in the northeast equatorial Pacific. Based on the color of sediments, sampled sediment cores were characterized into three lithologic units (unit 1,2, and 3). In all sediment cores, three units appear systematically; unit 1 lies at the top of cores and unit 2 and/or unit 3 appear to underlie unit 1 or alternate with unit 3. Unit 1 layer from the top of cores shows dark grayish brown to dark brown with mean thickness of 10.2cm. Unit 2 and 3 layers show very dark brown to black color and yellowish brown to brown color, respectively. According to the physical properties of the deep-sea sediment cores, sediment column can be divided into three sections. Section A $(0{\sim}15cm)$ in subbottom depth consists mostly of unit 1. Mean values of physical properties of section B $(15{\sim}30cm)$ in subbottom depth are similar to those of section C (>30 cm) in subbottom depth. However, the physical properties of section B were more variable than those of section C because of the high activity of bioturbation in section B. These results will provide valuable information for selecting suitable sites for mining manganese nodules in the Korea contract areas.

• Archives of Plastic Surgery
• /
• v.36 no.3
• /
• pp.361-364
• /
• 2009

Purpose: Sebaceous carcinoma is a rare malignant tumor derived from the adnexal epithelium of sebaceous glands. This tumor usually occurs on the eyelids, but uncommonly it may occur on the extraocular sites. It is characterized by a tendency of local recurrence and occasional metastasis. Surgical excision is appropriate treatment for patients with sebaceous carcinoma. Because this kind of case is rare, we report two cases of sebaceous carcinoma developed on scalp. Methods: Case 1 was a 69 - year - old woman. She visited the hospital with a $1.5{\times}2.5cm$ sized reddish yellow - colored, slowly growing mass on left parietal scalp. The mass began at birth and started growing at 5 years ago. Case 2 was a 67 - year - old woman. She had $2.5{\times}3.0cm$ sized yellow - colored mass on right parietal scalp. It occured at birth and started growing at 3 years ago. And the masses had erythematous ulcer with sanguineous discharge. In the beginning, the masses were miliary nodule. Results: CT scan and fine needle biopsy were done. Case 1 and 2 were diagnosed as sebaceous carcinoma. Wide excision with safety margin of 10 mm and split thickness skin graft was done. Histological examination revealed well demarcated, irregular, variable sized tumor lobules. Each lobule was composed of sebaceous and undifferentiated cells. Postoperatively, the patients did well and the lesion had not recurred. Conclusion: Sebaceous carcinoma is an aggressive malignant tumor. It often can be mistaken for other skin tumors. Authors experienced two rare cases of sebaceous carcinoma developed on scalp. We recommend early wide excision with enough safety margin as treatment of sebaceous carcinoma.

• Journal of Korean Society of Steel Construction
• /
• v.16 no.1 s.68
• /
• pp.43-49
• /
• 2004

With building structures becoming higher and having longer spans, new structural steel with better strength, thicker plate, and performance may be required rather than conventional structural steel. TMC steel is widely used in building structures largely due to its excellent seismic performance, superior weldability, and design strength that is not affected by plate thickness. To make use of TMC steel in pipe structures with large diameter and heavy wall, however, the this study, the degradation of material properties in submerged are welded SM520TMC steel pipes and tubes was evaluated using variable fabrication process and material change. Degradation test results showed that the yield and ultimate strength increased and elongation decreased regardless of the mode of fabrication, i.e., through roll bending or press forming, or steel used, i.e., domestic SM520TMC steel or SM520TMC steel from Japan.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.35 no.10
• /
• pp.891-898
• /
• 2007

Optimal aerodynamic design for the pitch-controlled horizontal axis wind turbine and its aerodynamic performance for various pitch angles are performed numerically by using the blade element momentum theory. The numerical calculation includes effects such as Prandtl‘s tip loss, airfoil distribution, and wake rotation. Six different airfoils are distributed along the blade span, and the special airfoil i.e. airfoil of 40% thickness ratio is adopted at the hub side to have structural integrity. The nonlinear chord obtained from the optimal design procedure is linearized to decrease the weight and to increase the productivity with very little change of the aerodynamic performance. From the comparisons of the power, thrust, and torque coefficients with corresponding values of different pitch angles, the aerodynamic performance shows delicate changes for just $3^{\circ}$ increase or decrease of the pitch angle. For precisive pitch control, it requires the pitch control algorithm and its drive mechanism below $3^{\circ}$ increment of pitch angle. The maximum torque is generated when the speed ratio is smaller than the designed one.

• The Journal of Engineering Geology
• /
• v.20 no.4
• /
• pp.415-424
• /
• 2010

A prototype of a Concrete-Faced Rock-fill Dam (CFRD) was constructed to evaluate the behavior of the materials in each zone within the dam. The tested materials, selected based on their grain size distribution, were used in constructing the prototype dam with layers of variable thickness, settlement ratio, and water content. We investigated the suitability of various values of hydraulic conductivity, water content, dry unit weight, and settlement ratio for zones within the dam. The test results revealed the relationships between the number of passes and the dry unit weight, between the dry unit weight and the settlement ratio, and between the settlement ratio and the number of passes. This paper focuses on the relationship between hydraulic conductivity and the number of passes. The results of the present analysis could be used to establish reasonable compaction standards for materials used in dam construction.

• Journal of Fashion Business
• /
• v.11 no.5
• /
• pp.15-34
• /
• 2007

This study held a questionnaire for men in their 60s or above to analyze the market research of slacks, understand the characteristics of their lower body types, and provide the basic data for the slacks pattern-making fitting the body types of senior citizens. The findings are as follows. According to the results of a questionnaire, elderly men preferred order-made slacks for better fitness, but they favored ready-made owing to the matter of prices. In particular, the girth of waist was the most considered when purchasing. However, as most customers tended to repair slacks length and the waist part, their unsatisfaction with sizes was rather high. In body measurements, elderly men had higher variable coefficients or more individual differences in the items of thickness and angles than in those of height, length, and girth. Factor analysis revealed 5 front and 6 side factors. According to the results of front-side somatotype analysis, pimento-flat, trapezoid-flat, and bent-flat types require narrower pattern designs in down-upper width than the middle-aged class. In addition, pimento-protruded hip and straight-jar types need to be designed in the same amount as in the middle-aged class. Based on the questionnaire results, down-upper length as 1cm above real dimensions was analyzed to have superior sense of wearing.

• Steel and Composite Structures
• /
• v.26 no.4
• /
• pp.473-484
• /
• 2018

Free vibration of cross-ply laminated plates using a higher-order shear deformation theory is studied. The arbitrary number of layers is oriented in symmetric and anti-symmetric manners. The plate kinematics are based on higher-order shear deformation theory (HSDT) and the vibrational behaviour of multi-layered plates are analysed under simply supported boundary conditions. The differential equations are obtained in terms of displacement and rotational functions by substituting the stress-strain relations and strain-displacement relations in the governing equations and separable method is adopted for these functions to get a set of ordinary differential equations in term of single variable, which are coupled. These displacement and rotational functions are approximated using cubic and quantic splines which results in to the system of algebraic equations with unknown spline coefficients. Incurring the boundary conditions with the algebraic equations, a generalized eigen value problem is obtained. This eigen value problem is solved numerically to find the eigen frequency parameter and associated eigenvectors which are the spline coefficients.The material properties of Kevlar-49/epoxy, Graphite/Epoxy and E-glass epoxy are used to show the parametric effects of the plates aspect ratio, side-to-thickness ratio, stacking sequence, number of lamina and ply orientations on the frequency parameter of the plate. The current results are verified with those results obtained in the previous work and the new results are presented in tables and graphs.