• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.21 no.1
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• pp.83-89
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• 1991

This study was performed to simulate various sizes of periapical lesions and condensing osteitis in bone and to clarify that condensing osteitis would give a greater radiographic contrast because of the more radiopacity immediately adjacent to the lesion and what the lamina dura on radiogram is in bone. For this study, two dry and wet human adult mandible and a cadaver were used. Each mandible was sectioned longitudinally to split lingual and buccal cortical plates to gain better access to the apex of tooth. Lesions were gradually enlarged and bordered with tooth ash that burned out at 950℃ for the reproduction of condensing osteitis in sequence. The serial radiograms were taken under the constantly maintained condition and compared with the actual lesions.

• Wind and Structures
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• v.30 no.2
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• pp.133-140
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• 2020

In this paper, critical fluid velocity and frequency of laminated pipe conveying fluid are presented. Each layer of the pipe is reinforced by functionally graded carbon nanotubes (FG-CNTs). The internal fluid is assumed turbulent and the induced forces are calculated by momentum equations. The pipe is resting on viscoelastic foundation with spring, shear and damping constants. The motion equations are derived based on classical shell theory and energy method. Differential quadrature method (DQM) is used for solution and obtaining the critical fluid velocity. The effects of volume percent and distribution of CNT, boundary condition, lamina layer number, length to radius ration of pipe, viscoelastic medium and fluid velocity are shown on the critical fluid velocity. Results show that with increasing the lamina layer number, the critical fluid velocity increases.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.2
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• pp.115-124
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• 2003

A prestressed concrete slab bridge is analyzed by the specially orthotropic laminates theory. Both the geometry and the material of the cross section of the slab are considered symmetrical with respect to the mid-surface so that the bending extension coupling stiffness, $B_{ij}=0$, and $D_{16}=D_{26}=0$. Each longitudinal and transverse steel layer is regarded as a lamina, and material constants of each lamina is calculated by the use of rule of mixture. This bridge with simple support is under uniformly distributed vertical and axial loads. In this paper, the finite difference method and the beam theory are used for analysis. The result of beam analysis is modified to obtain the solution of the plate analysis.

• Journal of the Korean Society for Advanced Composite Structures
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• v.1 no.4
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• pp.13-17
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• 2010

A post-tensioned slab bridge is analyzed by the specially orthotropic theory. Each longitudinal and transverse steel layer is regarded as a lamina, and material constants of each lamina is calculated by the use of rule of mixture. This slab bridge with simple support is under uniformly distributed vertical and axial loads. In this paper, the finite difference method and the beam theory are used for analysis. The result of beam analysis is modified to obtain the solution of the plate analysis. The result of this paper can be used for post-tensioned slab bridge analysis by the engineers with undergraduate study in near future.

• Journal of the Korean Society of Tobacco Science
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• v.17 no.2
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• pp.149-159
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• 1995

The freeze drying rate was investigated under various conditions such as pressure and moisture contents in order to establish the optimum condition for expansion of the culled flue cured tobacco lamina. The optimal pressure in the chamber to maintain the heat and mass transfer was about 0.8torr, When the moisture contents of sample was 50-60%, expanding rate was the optimum condition and the rate was 67-76%. As the thickness of the sample layers was increased, drying-rate was decreased conversely and this result seemed to be due to decline of heat and mass transfer coefficients. Differences with the position of its stalk were also observed in drying rate, and low stalk position leaves of 5 and 3 was the fastest. Key words : freeze drying, Popping, expansion tobacco.

• The Korean Journal of Zoology
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• v.34 no.1
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• pp.103-109
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• 1991

한국 특산종 Cobitis longicorpus (왕종개)의 주요 분류형질인 골절반의 지리적 변이를 조사하기 위하여 남한의 12개집단 205개체를 이용, 골질반의 type분석과 계수학분석을 실시하였다. Type분석 결과, 동해유입하천집단(영덕의 송천, 축산천, 경주 형산강, 울주 회야강)의 골질반은 등근 삼각형, 삼각형, 인각형으로 남해 유입하천 및 도서집단의 타원형, 반타원형, 부채꼴과 구별되었다. 골질반의 계수화분석 결과에서도 동해유입하천의 골질반 폭은 비교적 좁아 남해유입하천 및 도서지방과의 평균 CD값이 1.64로 새종 수준 이상의 차이를 보였다. 아울러 조사, 비교된 제 1 체측반문도 동해유입하천에서는 C. longicorpus의 특징이 전혀 나타나지 않아, 원기재질단인 섬진강집단을 포함한 남해유입하천 및 도서집단과 구별된 새종수준의 종분화가 이루어진 것으로 사료되었다.

• Korean Journal of Bronchoesophagology
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• v.1 no.1
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• pp.64-68
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• 1995

Vocal folds injury from vocal abuse is important topics of phonosurgery. Recent advances in diagnostic equipment, phonosurgery and speech analysis equipment have provided a lot of Information about fine movement of the vocal folds. However, predicting the reaction of the vocal folds to phonatory trauma remains difficult. The vocal folds need to withstand great vibratory and shearing stress and anchoring fibers of basement membrane Bone play a role in maintaining structural integrity of histologically different epidermis and superficial layer of lamina propria(cover of vocal folds). The purpose of this study is to demonstrate the changes of anchoring fibers in vocal polyp using transmission electron microscope. Various defects were observed : a irregular thickening of basement membrane, a near absence of normal anchoring fiber, a lot of electron dense material in superficial layer of lamina propria, a destruction of hemidesmosome and many vesicles carrying electron dense material In basal keratinocyte. These observations were suggestive of a hyperactivity of basal keratinocyte of vocal folds epithelium in response to vibratory stress.

• Structural Engineering and Mechanics
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• v.55 no.1
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• pp.79-92
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• 2015

In this study, free vibration analyses of symmetric laminated cantilever and simply supported damaged composite beams are investigated by using finite element method (FEM). Free vibration responses of damaged beams are examined using Euler Bernoulli beam and classical lamination theories. A computer code is developed by using MATLAB software to determine the natural frequencies of a damaged beam. The local damage zone is assumed to be on the surface lamina of the beam by broken fibers after impact. The damaged zone is modeled as a unidirectional discontinuous lamina with $0^{\circ}$ orientations in this study. Fiber volume fraction ($v_f$), fiber aspect ratio ($L_f/d_f$), damage length ($L_D$) and its location (${\lambda}/L$), fiber orientation and stacking sequence parameters effects on natural frequencies are investigated. These parameters are affected the natural frequency values significantly.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1991.06a
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• pp.13-13
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• 1991

후두는 호흡기가 시작되는 부위로 후두의 태생학적 연구는 타장기에서와 같이 정상 후두의 해부학적 이해, 후두 기형의 병인의 이해 및 치료에 기초 자료가 된다. 그러나 사람 배아의 후두 발생에 관한 연구는 재료확보가 용이하지 않고 해부학적 난이성으로 매우 드물다. 이에 저자는 사람 배아의 후두 발달을 연구하고자 배령이 확인된 20례의 배아(배령 4 주에서 8 주 까지)의 연속절편에서 광학현미경하에 후두 발달의 형태학적 관찰을 시행하여 다음과 같은 결과를 얻었다. 1. 배령 4 주에 median pharyngeal groove, laryngotracheal sulcus 와 tracheoesophageal septum 이 관찰되었다. 2. 배령 5 주에 hypopharyngeal eminence, epithelial lamina of larynx와 arytenoid swelling이 관찰되었다. 3. 배령 6 주에 hyoid condensation과 tracheoesophagealfistula가 관찰되었다. 4. 배령 7 주에 epiglottis 가 확인되었고 hyoid bone, thyroid lamina 와 cricoid cartilage 의 condensation 및 muscular condensation 이 관찰되었다. 5. 배령 8 주에 laryngeal cartilage의 chondrification과 ventricle이 관찰되었으며, vestibulotracheal canal과 pharyngotracheal canal 의 교통은 관찰되지 않았다.

• Journal of Species Research
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• v.2 no.1
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• pp.69-77
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• 2013

One newly recorded species, Dryopteris namegatae, sect. Hirtipedes, was collected in forests in Jeju-do. Dryopteris namegatae (vernacular name: 'Tam-ra-top-ji-ne-go-sa-ri') was distinguished from other Korean congeners of sect. Hirtipedes of the genus Dryopteris by having stiff black scales on stipe and rachis, less narrowed base of lamina, and adaxial surface of pinna immersed along veins. Dryopteris hangchowensis ('Gak-si-top-ji-ne-go-sa-ri', new local name), recorded without any comments and description, was reexamined with similar taxa and was distinguished by smaller plants, brilliant leaves, many prominent fimbriate blackish scales on stipe and rachis, long-pointed apex of lamina and pinna, halfway-lobed pinna, and narrowest pinna. Descriptions and illustrations of the two species and their photographs in the habitat are provided along with a key to the species of sect. Hirtipedes of Dryopteris in Korea.