• 한국실내디자인학회논문집
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• 제13호
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• pp.203-215
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• 1997

This Study typed the roof-design in analysis of structural design of the glulam architecture, developed worldwidely, nowaday. For this, it is studied the characters of glulam as the history of glulam architectures, manufacture of glulam, shapes and section of glulam, fireproof and combution of glulam. And it is studied roof-design according to structural type of glulam roof-structure. Conclusively, types of glulam roof design typied as 1)the Simple Beam str., 2)the Multi-Joints continous Beam str. 3)the Hinge str. 4)the Rahmen str. 5)the Archi str. 6)the Grid str. 7)etc str. (Folded-plate str., Radial str., Cylinder Shell str., Ring Dome str., Geodesic Dome str., Conic Coloid Shell str., H.P Shell str. Cantilever Shell str.)

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.631-636
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• 2008

The cylindrical shells are mainly used in the nuclear energy structure, pressure vessel, boiler and so on. When designing of shell structures, predicting the structure change under variety boundary conditions are necessary for estimating the safety. Design variables for the design engineer include multiple material systems and boundary conditions, in addition to overall structural design parameters. Since the vibration of stiffened cylindrical shell is an important consideration for structures design, the reliable prediction method and design methodology should be required. In this study, the optimum design of stiffened cylindrical shell for maximum natural frequency was studied by analytic and numerical method.

• 대한기계학회논문집A
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• 제31권4호
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• pp.451-460
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• 2007

The surface of 3D shell structure is created by using NURBS and nodes for generating finite element mesh on the surface are created by using external node offset method. In so doing the shortest distance between nodes on the top and bottom surface is searched and then the coordinates of nodes are determined by calculating the mid point of them in the middle of top and bottom surface. Triangular elements are formed on mid surface, and the average aspect ratio of the generated triangular elements are over 0.9.

• 전자공학회논문지B
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• 제32B권11호
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• pp.153-162
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• 1995

When vector quantization is used in low rate image coding (e.g., R<0.5), the primary problem is the tremendous computational complexity which is required to search the whole codebook to find the closest codevector to an input vector. Since the number of code vectors in a vector quantizer is given by an exponential function of the dimension. i.e., L=2$^{nR}$ where Rn. To alleviate this problem, a multiple shell structure of hypercube feature maps (MSSHFM) is proposed. A binary HFM of k-dimension is composed of nodes at hypercube vertices and a multiple shell architecture is constructed by surrounding the k-dimensional hfm with a (k+1)-dimensional HFM. Such a multiple shell construction of nodes inherently has a complete tree structure in it and an efficient partial search scheme can be applied with drastically reduced computational complexity, computer simulations of still image coding were conducted and the validity of the proposed method has been verified.

• International Journal of Naval Architecture and Ocean Engineering
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• 제12권1호
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• pp.680-690
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• 2020

In ocean environment, the sound speed gradient of seawater has an important influence on far field sound propagation. The FEM/BEM is used to decouple the vibroacoustic radiation of the spherical shell, and the Green function of the virtual source chain is adopted for decoupling. For far field radiated Sound Pressure Level (SPL), the Beam Displacement Ray normal Mode (BDRM) is employed. The vibration and near-/far-field radiated SPL of spherical shell is analyzed in shallow sea uniform layer, negative/positive gradient, negative thermocline environment, and deep-sea sound channel. Results show that the vibroacoustic radiation of spherical shell acted at 300Hz can be analogous to dipole. When the radiated field of the spherical shell is dominated by large-grazing-angle waves, it can be analogous to vertically distributed dipole, and the far field radiated SPL is lower; while similar to horizontally distributed dipole if dominated by small-grazing-angle waves, and the far field SPL is high.

• 폴리머
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• 제26권2호
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• pp.227-236
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• 2002

열가역적인 polyvinylidene fluoride (PVDF)/propylene carbonate (PC) 의 매우 묽은 농도에서의 pregel 상태의 구조를 레이저 광산란법으로 조사한 결과 겔형성농도의 100배 이상 묽은 농도 조건에서도 PVDF 사슬은 낱개로 용해되어 있는 것이 아니라 많은 PVDF 사슬들이 응집된 거대한 구형 상태로 존재하며 이때의 응집체의 분산도는 상당히 낮으며 용액온도 $40^{\circ}C$에서 회전반경$R_G$ 는 232 nm, 동력학적 반경 $R_H$는 407 nm로 측정되었다. $R_H/R_G$=1.75의 커다란 비 값, 극소점을 갖는 정적 광산란 패턴 등으로부터 예측하건대 이 응집체의 구조는 core-shell 형태의 구형이며, 이때 내부 core의 반지름은 대략 215 nm, 외부 shell의 두께는 192 nm가 되며, shell 부분에서의 PVDF의 단량체 밀도는 core 부분의 단량체 밀도의 약 75% 수준에 머무르는 것으로 판명되었다.

• Bulletin of the Korean Chemical Society
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• 제30권7호
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• pp.1485-1488
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• 2009

A facile, seed-mediated preparation method of trimetallic Au@Pb@Pt core-shell nanoparticles is developed. Au nanoparticles are the template seeds onto which sequentially reduced Pb and Pt are deposited. The trimetallic core-shell structure is confirmed by UV-Vis spectroscopy, TEM and EDS analysis, and cyclic voltammetry. The trimetallic Au@Pb@Pt core-shell nanoparticles show high electrocatalytic activity for formic acid and methanol electrooxidation.

• 한국정보통신학회논문지
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• 제2권1호
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• pp.37-43
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• 1998

This article describes the application of a coupled finite element-boundary element method to obtain the steady-state response of a sonar transducer. The particular structure considered is a flooded piezoelectric spherical shell. The sonar shell is simulated to be driven by electrical charges applied onto inner and outer surfaces of the shell. It is shown that at relatively low input frequency a beam pattern which is almost close to omnidirection can be obtained. The coupled FE-BE method is described in detail.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2005년도 춘계학술발표대회 개요집
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• pp.270-272
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• 2005

• Advances in concrete construction
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• 제13권5호
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• pp.367-376
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• 2022

Theoretical study of vibration distinctiveness of rotating cylindrical are examined for three volume fraction laws viz.: polynomial, exponential and trigonometric. These laws control functionally graded material composition in the shell radius direction. Functionally graded materials are controlled from two or more materials. In practice functionally graded material comprised of two constituent materials is used to form a cylindrical shell. For the current shell problem stainless steel and nickel are used for the shell structure. A functionally graded cylindrical shell is sanctioned into two types by interchanging order of constituent materials from inner and outer side for Type I and Type II cylindrical shell arrangement. Fabric composition of a functionally graded material in a shell thickness direction is controlled by volume fraction law. Variation of power law exponent brings change in frequency values. Influence of this physical change is investigated to evade future complications. This procedure is capable to cater any boundary condition by changing the axial wave number. But for simplicity, numerical results have been evaluated for clamped- simply supported rotating cylindrical shells. It has been observed from these results that shell frequency is bifurcated into two parts: one is related to the backward wave and other with forward wave. It is concluded that the value of backward frequency is some bit higher than that forward frequency. Influence of volume fraction laws have been examined on shell frequencies. Backward and forward frequency curves for a volume fraction law are upper than those related to two other volume fraction laws. The results generated furnish the evidence regarding applicability of present shell model and also verified by earlier published literature.