• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2011년도 춘계학술대회 및 Fine pattern PCB 표면 처리 기술 워크샵
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• pp.165-166
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• 2011

conical type의 sputtering 시스템으로 3차원 치과 보철물 위에 균일한 Ti 박막의 증착을 시도하였으며, 증착 변수에 따른 Ti 박막의 특성을 조사하였다.

• 한국터널지하공간학회 논문집
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• 제21권1호
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• pp.49-59
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• 2019

본 연구는 로터리드럼커터에 적용된 두 종류의 코니컬 픽커터에 대한 현장시험을 통해 시험 전과 후의 육안조사와 중량감소 및 마모부피를 측정하여 코니컬 픽커터의 내구성을 비교 분석하였다. 육안조사를 통해 슬림 타입 코니컬 픽커터에서만 총 9개의 삽입재 손실이 나타남을 확인하였고 삽입재 보호를 위해 두부의 두께가 중요함을 알 수 있었다. 시험 전과 후의 픽커터의 중량손실과 마모부피는 헤비타입이 슬림타입에 비해 반이하로 작게 나타나 경암반에서 헤비타입이 더 유용함을 확인할 수 있었다. 픽커터의 마모손실을 판단할 때, 중량측정과 마모부피 측정결과의 상호 비교는 재료의 단위중량과 굴착에 의한 스폴링에 의해 차이가 나타날 수 있으므로 주의해야 할 것으로 판단된다.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2003년도 추계학술발표대회 요약집
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• pp.111.2-111.2
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• 2003

• Tribology and Lubricants
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• 제21권1호
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• pp.27-32
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• 2005

This paper shows a performance analysis for step type and conical type sealess cylinders. 2 dimensional Reynolds equation and finite difference numerical techniques are utilized for the performance analysis and the piston design. Centering forces of conical pistons are higher than those of step ones. Also, leakage flows of conical pistons are lower than those of step ones. But, the step type piston is practically suggested to apply for sealess cylinders because it is difficult that conical portion is precisely manufactured.

• 한국산업융합학회 논문집
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• 제25권4_2호
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• pp.637-644
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• 2022

In this study, the flow characteristics according to the shape of the vortex nozzle was studied by numerical analysis and the amount of microbubble generation was measured experimentally. The shape of the vortex nozzle is cylindrical, diffuser, and conical type. The axial fluid velocity in the induced tube gradually increased from the inlet to the outlet. In particular, the fluid velocity in the nozzle part increased rapidly. The velocity distribution of the fluid at the inlet of the induced tube showed that the flow rotates counterclockwise in the outer region and the inner center of the induced tube. At the outlet of the induced tube, the cylindrical and conical type showed rotational flow, and the diffuser type showed irregular turbulent flow. The dimensionless pressure ratio 𝜂 of the inner region of the induced tube was lower than that of the outer region. Also, 𝜂 near the outlet of the induced tube in cylindrical and conical type showed a similar tendency to the inlet area. At the outer region of inlet of induced tube, intense vorticity was observed on the wall and in lower region. At the inner region of inlet of induced tube, intense vorticity was observed on the inner wall of the induced tube and in the central region of the inlet of the induced tube. At the outlet of induced tube, in the case of the cylindrical and conical type, intense vorticity was observed near the inner wall, the diffuser type showed irregular strong vorticity inside the tube. The total number of bubbles measured was the most in the cylindrical type, and the microbubbles less than 50mm occurred the most in the conical type.

• Structural Engineering and Mechanics
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• 제45권2호
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• pp.259-275
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• 2013

Free vibration of symmetric angle-ply layered conical shell frusta of variable thickness is analyzed under shear deformation theory with different boundary conditions by applying collocation with spline approximation. Linear and exponential variation in thickness of layers are assumed in axial direction. Displacements and rotational functions are approximated by Bickley-type splines of order three and obtained a generalized eigenvalue problem. This problem is solved numerically for an eigenfrequency parameter and an associated eigenvector of spline coefficients. The vibration of three and five-layered conical shells, made up of two different type of materials are considered. Parametric studies are made for analysing the frequencies of the shell with respect to the coefficients of thickness variations, length-to-radius ratio, length-to-thickness ratio and ply angles with different combination of the materials. The results are compared with the available data and new results are presented in terms of tables and graphs.

• 식물분류학회지
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• 제43권2호
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• pp.106-117
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• 2013

한국산 Potentilleae족의 Fragariinae아족과 Potentillinae아족에 포함된 8속 27분류군을 대상으로 주사전자 현미경을 이용하여 잎 양면과 엽병의 털 및 잎 표면의 미세구조를 관찰하였다. 연구결과 한국산 Potentilleae족의 잎과 엽병의 털은 크게 4가지 유형으로 구분되었다(Type I: conical hirtellous, type II: verruculose conical hirtellous, III: crispate villous, IV: floccose villous). Type I은 Fragariinae아족과 Potentillinae아족의 대부분의 분류군에서 관찰되었고, Type II는 유일하게 Potentillinae아족 Potentilla속 Conostylae절의 P. cryptotaeniae에서 나타났다. Type III은 Potentilla속 Conostylae절의 P. chinensis complex와 Leptostylae절의 P. egedii에서 나타났고, type IV는 Conostylae절의 P. discolor와 P. nivea에서 관찰되었다. 융모형인 Type III과 IV를 갖는 분류군들에서는 미세강모가 함께 나타났다. 서로 다른 아족 혹은 절간에 동일한 털 유형을 공유하고 있으며, 한 종에서 두 가지 이상의 털 유형이 관찰되기도 하였다. Type I에 해당하는 Fragariinae아족 다수의 분류군과 Potentillinae아족의 P. centigrana와 P. dickinsii complex에서는 잎 표면에 표피상납질이 발달하였다. 이들의 분포 패턴을 고려하였을 때 아족 간에 표피상납질을 공유하는 특성은 서식지의 생태적 환경과 관련되었을 가능성이 있다. 그러나 분자 계통분류학적인 연구와 비교한 결과 계통적인 영향 또한 관련되었을 것으로 판단된다.

• Steel and Composite Structures
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• 제43권5호
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• pp.603-623
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• 2022

This article is dedicated to predict the natural frequencies of joined conical shell structures made of Functionally Graded Material (FGM). The structure includes two conical segments. The equivalent material properties are found by using the rule of mixture based on Voigt model. In addition, three well-known patterns are employed for distribution of material properties throughout the thickness of the structure. The main objective of the present research is to propose a novel exponential pattern and obtain the related equivalent material properties. Furthermore, the Donnell type shell theory is used to obtain the governing equations of motion. Note that these equations are obtained by employing First-order Shear Deformation Theory (FSDT). In order to discretize the governing system of differential equations, well-known and efficient semi-analytical scheme, namely Generalized Differential Quadrature Method (GDQM), is utilized. Different boundary conditions are considered for various types of single and joined conical shell structures. Moreover, an applicable modification is considered for the continuity conditions at intersection position. In the first step, the proposed formulation is verified by solving some well-known benchmark problems. Besides, some new numerical examples are analyzed to show the accuracy and high capability of the suggested technique. Additionally, several geometric and material parameters are studied numerically.

• 전기학회논문지
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• 제60권9호
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• pp.1727-1732
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• 2011

In order to realize a high performance(low loss, high isolation) microwave power divider/combiner, we have designed the power combiner/divider precisely in accordance with the different hight of central part. In the case of the high central part of the hight of $h_r$=10.2, a compensating part of the conical line is inserted in the conical conversion transmission line, and in the case of low central part of the hight of $h_r$=5.0, the conical conversion transmission line is remodeled into the 2-stage bend structure. In both case, the reflection characteristics are improved to 30dB over the operating frequency range of 5GHz bandwidth. A resistance is inserted between the peripheral ports so as to try to improve the isolation characteristics of the device. For the 16-divider/combiner, the isolation characteristics are improved to 10dB over the operating frequency range of 5GHz bandwidth.

• Structural Engineering and Mechanics
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• 제43권1호
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• pp.89-103
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• 2012

In this study, the stability of laminated homogeneous and non-homogeneous orthotropic truncated conical shells with freely supported edges under a uniform hydrostatic pressure is investigated. It is assumed that the composite material is orthotropic and the material properties depend only on the thickness coordinate. The basic relations, the modified Donnell type stability and compatibility equations have been obtained for laminated non-homogeneous orthotropic truncated conical shells. Applying Galerkin method to the foregoing equations, the expression for the critical hydrostatic pressure is obtained. The appropriate formulas for the single-layer and laminated, cylindrical and complete conical shells made of homogeneous and non-homogeneous, orthotropic and isotropic materials are found as a special case. Finally, effects of non-homogeneity, number and ordering of layers and variations of shell characteristics on the critical hydrostatic pressure are investigated.