• 한국정밀공학회지
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• 제21권6호
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• pp.172-178
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• 2004

Tungsten carbide microshaft can be used as various micro-tools for MEMS because it has high hardness and high rigidity. In this study, experiments are performed to produce tungsten carbide micro-shaft using electrochemical etching. H$_2$SO$_4$ solution is used as electrolyte because it can dissolve tungsten and cobalt simultaneously. Optimal electrolyte concentration and machining voltage satisfying uniform shape, good surface quality, and high MRR of workpiece are experimentally found. By controlling the various machining parameters, a straight micro-shaft with 5 ${\mu}{\textrm}{m}$ diameter, 3 mm length, and 0.2$^{\circ}$taper angle was obtained.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.919-924
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• 2005

Fretting-wear caused by turbulence excitation for KSNP(Korea standard nuclear power plant) steam generator is investigated numerically. Secondary sides density and normal velocity are obtained by the thermal-hydraulic data of the steam generator. Because nonlinear finite element analysis is complex and time consuming, work rate is estimated by using linear analysis for simple straight 2-span tube. Wear volume and depth by using work rate calculation are estimated. Span length, secondary side fluid density and normal velocity are adopted to study the effects on the fretting-wear by turbulence excitation. When secondary sides density and normal velocity is increased, It turns out that secondary side density and normal gap velocity are very important paramater for fretting-wear phenomena of the steam generator.

• Structural Engineering and Mechanics
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• 제27권3호
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• pp.293-310
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• 2007

Theoretical foundation for the buckling load determination in reinforced concrete columns is described and analytical solutions for buckling loads of the Euler-type straight reinforced concrete columns given. The buckling analysis of the limited set of restrained reinforced concrete columns is also included, and some conclusions regarding effects of material non-linearity and restrain stiffnesses on the buckling loads and the buckling lengths are presented. It is shown that the material non-linearity has a substantial effect on the buckling load of the restrained reinforced concrete columns. By contrast, the steel/concrete area ratio and the layout of reinforcing bars are less important. The influence on the effective buckling length is small.

• 한국수소및신에너지학회논문집
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• 제32권1호
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• pp.63-67
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• 2021

Accurate measurements of the heat transfer coefficients of concentric annular space for the test section is important to measure the tube-side heat transfer coefficients of working fluids. This paper presents the annular side heat transfer coefficients of concentric annuli with variation of tube diameter ratios using Wilson plot method. The test facility has a straight, horizontal test section with an active length of 3.0 m. Inner/outer diameters of test tubes are 7.0/7.5 and 8.0/8.56 mm, respectively. An outer diameter of annulus side is 16.0 mm. The test results show that convective heat transfer coefficients in annuli increase with annular diameter ratio. The correlations for convective heat transfer coefficients in annuli are also developed.

• Animal Systematics, Evolution and Diversity
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• 제39권1호
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• pp.53-57
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• 2023

During a survey for the southern sea of Korea, an iphiculid crab, Pariphiculus coronatus, was newly recorded from Korea. Specimens were obtained at a depth of 109-120 m near Jejudo Island. Pariphiculus coronatus can be distinguished from congeners by the following characters: the carapace length and the carapace width subequal, the surface of carapace covered with round granules, the medial tubercles of the intestinal and cardiac region of the carapace, and the first gonopod curved in the half region and straight in the distal portion. The Korean leucosiods have 16 genera and 20 species so far. Here we provide the diagnosis and illustration of Pariphiculus coronatus.

• 한국재료학회지
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• 제34권3호
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• pp.144-151
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• 2024

This work focuses on the fabrication of excellent magnetic structures for trapping breast cancer cells. Micromagnetic structures were patterned for trapping cancer cells by depositing 30 nm of permalloy on a silicon substrate. These structures were designed and fabricated using two fabrication techniques: electron beam lithography and laser direct writing. Two types of magnetic structures, rectangular wire and zig-zagged wire, were created on a silicon substrate. The length of each rectangular wire and each straight line of zig-zagged wire was 150 ㎛ with a range of widths from 1 to 15 ㎛ for rectangular and 1, 5, 10 and 15 ㎛ for zigzag, respectively. The magnetic structures showed good responses to the applied magnetic field despite adding layers of silicon nitride and polyethylene glycol. The results showed that Si + Si₃N₄ + PEG exhibited the best adhesion of cells to the surface, followed by Si + Py + Si₃N₄ + PEG. concentration of 5-6 with permalloy indicates that this layer affected silicon nitride in the presence of Polyethylene glycolPEG.

• 한국해안해양공학회지
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• 제14권3호
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• pp.232-239
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• 2002

본 논문에서는 조위변화에 따른 오탁방지막 계류라인의 거동을 조사하였다. 거동분석으로부터 안전율을 고려하여 팽팽하게 적정케이블의 길이를 정하면 수심이 하강하더라도 긴장측 케이블은 거의 일정한 장력을 유지하는 것을 알 수 있었다 그러나, 이완케이블의 기능은 상실되어 구조체 전체의 불안정성을 초래할 수도 있는 것을 알 수 있었다. 또한, 초기 직선긴장각이 계류거동에 미치는 영향을 조사해봄으로써 케이블 장력, 수중부상길이 케이블길이(재료량과 관계 있음)및 부체변위 등을 복합 고려하면서 계류 해석하여야만 적정한 설계를 할 필요가 있을 것으로 보였으며, 막체의 부착물로 인한 케이블의 장력은 줄어들어 재료손상은 일으키지 않으나 저면 앵글, Total scope 및 부체변위에 영향을 미쳐 구조물 전체의 불안정성을 초래할 수 있다는 것도 알 수 있었다.

• 한국의류산업학회지
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• 제20권3호
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• pp.266-278
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• 2018

This study investigated the transformation of the Chanel jacket by looking at clothing design and constructional components. This study explored Chanel jacket's designs from 2001 S/S to 2016-17 F/W, and collected designs from Samsung Design Net and Vogue. The study used 690 designs with the following results. First, in the silhouette of the Chanel jacket, straight silhouette and hourglass silhouette had the most; in addition, in the length, hip line and under hip line were in order. Second, in case of collar and neckline, the form of a non-collar was the most and revealed the persistence of round neckline which is the basic style of a Chanel jacket. Third, in the shape of sleeves, the loose-fit straight sleeves, wide sleeves, and cocoon sleeves appeared most often. In method of closure, button, zipper were in order, and snaps or without closure appeared. Fourth, in the form of braids, various forms such as twisted yarns, leashes, or lace were used, and patch pockets were mainly used in pockets. Chanel maintains its original design by using various methods. Chanel tried to improve activity and functionality through silhouettes, lengths, necklines, and sleeves. The unchanging expression of the world of Chanel will continue to display and inherit future value. This study can provide Chanel's unique characteristics and new ideas that can transform their origins for jacket design.

• 한국입자에어로졸학회지
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• 제9권4호
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• pp.231-238
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• 2013

Carbon nanotubes (CNTs) are one of the nanomaterials that were discovered by Iijima in 1991 for the first time. CNTs have long cylindrical and axi-symmetric structures. CNTs are made by rolling graphene sheets. Because of their large length-to-diameter ratio, they are called nanotubes. CNTs are categorized as single-walled carbon nanotubes (SWCNTs) or multi-walled carbon nanotubes (MWCNTs) based on the shell structures. CNTs are broadly used in various fields, such as scanning probe microscopy, ultra fine nano balance and medicine, due to their extraordinary thermal conductivity, electrical and mechanical properties. Because long, straight CNTs have the same shape as asbestos, which cause cancer in cells lining the lung, there have been many studies on the effects of MWCNTs on human health that have been conducted. Stable atomization of CNTs is very important for the estimation of inhalation toxicity. In the present study, electro-static assisted axial atomizer (EAAA), which is the instrument that uses MWCNTs and aerosolizes them by transforming the single fiber shape using ultrasonic dispersion and electric field, was invented. EAAA consists of a ultrasonic bath for dispersion of MWCNTs and a particle generator for atomizing single fibers. The performance evaluation was conducted in order to assess the possibilities of 6-hour straight atomization with stability, which is the suggested exposure time in a day for the estimation of inhalation toxicity.

• 한국의류산업학회지
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• 제8권5호
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• pp.496-504
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• 2006

This study was conducted for silver generation women, age 60 and more. Questionnaire was answered by the total 291 of women. Frequency analysis, t-test, ANOVA and Duncon-Test have been completed by using SPSS 12.0 tool. The conclusion of the study is below. First, silver generation women live in Seoul and South Gyeongsang Province. The data shows huge academic background gab among regions. Second, the following is the preferences found by 15 stimulants which expert groups identified based on demography. People in South Gyeongsang Province like default, tailored, three-button jacket more. People in South Gyeongsang Province prefer to Chanel jackets and people in their 70s prefer to it than in 60s, stand collar casual jacket for color and material, and the less they are educated, the more they like the jackets. And those who have less personal expenses tend to prefer to it. South Gyeongsang Province shows preference for semi polo-neck sweater. Highly educated did not show any preference for it. Women in their 70s tend to like blouses with round neckline. The data shows there is significant difference of preference for design, color and material for coloration vest between education levels. The less educated tends to like it. People in South Gyeongsang Province and those who live with their children are in favor with half sleeve jackets for colors and materials. All in Seoul and South Gyeongsang Province do not like three-quarter-length sleeve jackets because those jacket have wide and deep plunging neckline. The study showed people living in Seoul, in their 60s, highly-educated tend to favor polo shirts significantly. Seoul favor basic straight pants and people with any level of education excluding elementary prefer to it. The highly-educated and those who have a bigger allowance tend not to prefer to baggy trousers. In conclusion, Fifteen incentives (clothing design) for semi polo-neck sweaters, polo t-shirts, basic straight pants are more proper to silver generation women in their 60s, living in Seoul. Other designs are desirably applicable to customers on a national scale at middle prices.