• Fibers and Polymers
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• 제7권3호
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• pp.276-285
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• 2006

Development and numerical implementation for an elastoplastic constitutive model for anisotropic and asymmetric materials are presented in this paper. The Coulomb-Mohr yield criterion was modified to consider both the anisotropic and asymmetric properties. The modified yield criterion is an isotropic function of the principal values of a symmetric matrix which is linearly transformed from the Cauchy stress space. In addition to the constitutive equation, the numerical treatment for the singularity in the vertex region of yield surface and stress integration algorithm based on elastoplasticity were presented. In order to assess the accuracy of numerical algorithm, isoerror maps were considered. Also, extension of a strip with a circular hole was simulated and results compared with those obtained using the (smooth) Mises yield criterion to validate stress output for a complex stress state.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권4호
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• pp.229-236
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• 2004

In this paper, the effect of permanent magnet overhang structure on the characteristics in Brushless DC motor has analyzed quantitatively. We classified the overhang structure as symmetric and asymmetric. 3D equivalent magnetic circuit network (EMCN) method which uses the permeance as the distributive variable is used for the efficient analysis of magnetic field. The overhang effect which increases the linkage flux at the stator is verified by comparison between overhang and no overhang structure. In addition, it is known that no load back electro motive force (EMF) is also increased due to the overhang effect. In case of asymmetric overhang structure, the ratio effect of the upper to lower overhang length on the magnetic forces is analyzed. Form the analysis results, the variation of the asymmetric overhang ratio has a significant effect on the axial magnetic force except the radial and tangential magnetic forces. The validity of the analysis results is also clarified by comparison between calculated results and measured ones such as back EMF and cogging torque.

• 전기학회논문지
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• 제57권8호
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• pp.1416-1421
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• 2008

A 10 dB branch line hybrid coupler included with defected ground structure (DGS) is proposed. In this contribution, a contact between the grounded metal housing and DGS is avoided, which has been a serious problem in applying DGS to high frequency circuits. An isolation between the metal housing and the DGS pattern is provided by inserting additional substrate between DGS and the metal package. Therefore, it is possible to design branch line hybrid couplers having highly asymmetric power dividing ratio using these DGS structure, which is demonstrated in this paper. The designed and fabricated branch line hybrid coupler using DGS is well packaged in a metal housing without touching the ground metal directly. The measurement is performed under realistic practical operating situations because it is packaged in a metal housing. The measured performances of the fabricated 10dB coupler shows a 1:9 asymmetric power dividing ratio at output ports, as predicted. In addition, the measured performances in terms of matching, isolation, and phase difference are in excellent agreement with the simulated characteristics.

• Structural Engineering and Mechanics
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• 제77권4호
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• pp.463-472
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• 2021

Fully rigid floor diaphragm is one of the main assumptions that are widely used in common practices due to its simple application. However, determining the exact degree of diaphragms flexibility cannot be easily accomplished without finite element modeling, which is an expensive and time-consuming procedure. Therefore, it is always possible that apparently rigid diaphragms, based on prescriptive limitations of seismic codes, experience some degrees of flexibility during the earthquakes. Since diaphragm flexibility has more uncertainties in asymmetric-plan structures, this study focuses on errors resulting from probable floor diaphragm flexibility of torsionally restrained structures. The analytical models used in this study were single-story buildings with asymmetric plan and RC shear walls. Although floor system is not considered explicitly, a wide range of considered diaphragm flexibility, from fully rigid to quite flexible, allows the results to be generalizable to a lot of lateral load resisting systems as well as floor systems. It has been shown that in addition to previously known effects of diaphragm flexibility, presence of orthogonal side elements during design procedure with rigid diaphragm assumption and rapid reduction in their absorbed forces can also be an important source to increase errors due to flexibility. Accordingly, from the obtained results the authors suggest designers to consider the possibility of diaphragm flexibility and its adverse effects, especially in torsionally restrained systems in their common designs.

• 한국안전학회지
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• 제37권3호
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• pp.45-51
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• 2022

This paper focuses on a recently proposed asymmetric base-isolation coupling control system (ABiCS) for the vibration control of adjacent twin buildings. The ABiCS consists of inter-story diagonal dampers, a connecting damper between the two buildings, and a seismic isolation device at the base floor of one building. To investigate the control characteristics of ABiCS, a parametric study was performed by numerically simulating the 20-story twin buildings. In the parametric study, the control capacities of the inter-story diagonal dampers, connecting damper, and seismic isolation device were considered as varying parameters. The parametric study results indicate that the connecting damper between the two buildings reduces the responses of both buildings only at optimal or near-optimal capacity. In addition, adjusting the stiffness of the base isolation is found to be the most effective method for improving seismic performance and achieving cost-effectiveness. Accordingly, we presented a scenario-based performance improvement approach in which reducing the stiffness of the base isolation device could be an effective technique to improve the seismic performance of both buildings. However, note that checking the maximum allowable displacement of the base isolation device is essential.

• 한국의류학회지
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• 제47권3호
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• pp.511-530
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• 2023

This study aims to analyze middle-aged men's frontal body shape asymmetry by measuring the left and right body dimensions and angles of 388 middle-aged men aged 40 to 59 using 3D body scan data and comparing the measured values. The study also compares the measured values of width, height, and angle and their relationships using Size Korea's anthropometric measurement and posture index of the New York Posture Rating Scale. The results confirm that the asymmetric shape characteristics of the upper and lower body appear differently. In addition, the asymmetrical characteristics between the upper and lower body differed, indicating that the close parts of the body affect each other. Similar to the difference in the left and right frontal body shapes and the average angle distribution, the asymmetrical upper and lower body characteristics also are found to be dissimilar when the correlations are examined. In contrast, there is no asymmetry in the width, height, and angle considering the age and BMI groups. Finally, the study classifies three body types and identifies their asymmetric characteristics. Overall, this study contributes primary data for further research on pattern production for asymmetric and unique body types and the development of customized apparel products.

• 한국전기전자재료학회논문지
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• 제33권1호
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• pp.25-30
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• 2020

Oxide (SiO₂)/Metal(Ag)/Oxide(SiO₂, ITO, ZnO) multilayer films were fabricated using a magnetron sputtering technique at room temperature on Si (p-type, 100) and a glass substrate. The electrical and optical properties of the asymmetric multilayer films depended on the thickness of the mid-layer film and the type of oxide in the bottom layer. As the metal layer becomes thicker, the sheet resistance decreases. However, the transmittance decreases when the metal layer exceeds a threshold thickness of approximately 10~12 nm. In addition, the sheet resistance and transmittance change according to the type of oxide in the bottom layer. If the oxide has a large resistivity, the overall sheet resistance increases. In addition, the anti-reflection effect changes according to the refractive index of the oxide material. The optical and electrical properties of multilayer films were investigated using an ultraviolet visible (UV-Vis) spectrophotometer and a 4-point probe, respectively. The optimum structure is SiO₂ (30 nm)/Ag (10 nm)/ZnO (30 nm) multilayer, with the highest FOM value of 7.7×10^-3 Ω^-1.

• 복식
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• 제57권9호
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• pp.161-176
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• 2007

The objectives of this study are to select and analyze unpublished wedding dresses in the 19th century, to investigate the design characteristics and making techniques of Victorian wedding dresses, and to examine the correlation between the wedding dress style and the fashion style in those days and the influence of the wedding dress style on contemporary's styles. The materials of this study were 9 wedding dresses owned by the Historical Costume and Textile Collection at the University of Connecticut in USA. The dresses were made during the mid and late Victorian Age. As for silhouette, the bustle style was popular in the 1870s and 1880s, and the hourglass style in the 1890s, and different from contemporary dresses there were no big differences in structural pattern and details between ordinary dresses and wedding dresses. In addition, colored wedding dresses were used until the mid and late Victorian Age, but since the wedding ceremony of Queen Victoria in 1840, white wedding dress was widely accepted and settled as the tradition of today's wedding dresses. While the Western dress style had been basically a one piece style, there appeared simple two piece designs in which the upper garment was separated from the lower one, from the mid Victorian Age. This is considered the reflection of those days' pragmatic social trend in dress style. It seems around 1875 when asymmetric design was first introduced in the Western dress style, which had been mostly symmetric. The asymmetric style that pursued atypical beauty, though not common during the late Victorian Age, shows a change in the typical Western dress style. With regard to dress making techniques, sewing machines were distributed widely during the early Victorian Age but they were not used in all parts of dress. Most of details and trimming works were done manually and some parts were attached and detached by hand sewing. In addition, not like today, there were no generalized rules of making such as the form of closings and composition.

• 멤브레인
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• 제24권1호
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• pp.50-62
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• 2014

상 전이 공정을 이용하여 polysulfone계 비대칭 정밀 여과막을 제조하였다. Polysulfone/N-methyl-2-pyrrolidone/polyvinylpyrrolidone/phosphoric acid계로 이루어진 casting 용액을 사용하였으며 응고조로는 물을 사용하였다. 멤브레인 제조공정에 적용된 상 전이 공정으로 증기 유도 상 전이 공정을 적용하였으며 상대습도 74%에서 캐스팅 판의 온도와 노출 시간을 조절한 결과 기공의 크기와 구조에 있어 변화를 관찰할 수 있었다. 제조된 멤브레인의 구조는 SEM과 microflow permporometer를 사용하여 조사하였다. Phosphoric acid의 첨가는 조밀한 스펀지 형태의 멤브레인을 느슨한 스펀지 형태의 멤브레인으로 변화시켰으며 촉매량의 Phosphoric acid 첨가로도 평균 기공크기는 거의 $0.2{\mu}m$ 정도 커지고 유량도 약 3,000 LMH가 증가하였다. 캐스팅 판의 온도와 노출 시간의 변화는 표면층의 구조, 기공의 크기 및 공극률에 큰 변화를 가져옴을 확인할 수 있었다.

• Bulletin of the Korean Chemical Society
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• 제30권1호
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• pp.23-24
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• 2009