• Fibers and Polymers
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• 제7권3호
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• pp.317-322
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• 2006

Reduction of yam hairiness by nozzles in ring spinning and winding is a new approach. Simulation of the airflow pattern inside the nozzles provides useful information about actual mechanism of hairiness reduction. The swirling air current inside the nozzles is capable of wrapping the protruding hairs around the yam body, thereby reducing yam hairiness. Since production rate of winding is very high and the process itself increases yarn hairiness any method to reduce the hairiness of yarns at this stage is a novel approach. A CFD (computational fluid dynamics) model has been developed to simulate the airflow pattern inside the nozzles using Fluent 6.1 software. In this study, both S- and Z-type nozzles having an axial angle of 500 and diameter of 2.2 mm were used for simulation studies. To create a swirling effect, four air holes of 0.4 mm diameter are made tangential to the inner walls of the nozzles. S- and Z-twisted yams of 30 tex were spun with and without nozzles and were tested for hairiness, tensile and evenness properties. The total number of hairs equal to or exceeding 3 mm (i.e. the S3 values) for yam spun with nozzle is nearly 49-51 % less than that of ring yams in case of nozzle-ring spinning, and 15 % less in case of nozzle-winding, while both the yarn types show little difference in evenness and tensile properties. Upward airflow gives best results in terms of hairiness reduction for nozzle-ring and nozzle wound yams compared to ring yarns. Yarn passing through the centre of the nozzle shows maximum reduction in S3 values.

• 대한환경공학회지
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• 제34권12호
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• pp.835-839
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• 2012

도심의 교통량의 증가와 더불어 급증하는 교통소음의 피해를 최소화하기 위하여 도로변 지역에 방음벽의 설치가 이루어지고 있다. 이에 따라 여러 형태의 방음벽 설치되었고, 그 형태와 재질에 따라방음성능, 시야확보측면, 유지관리 등에서 장단점이 존재한다. 최근 꾸준하게 적용되고 있는 반사형 투명형 방음벽의 경우, 시야를 확보할 수 있고 외관이 우수하지만 반사음의 영향을 고려해야 하는 단점이 있다. 본 연구에서는 방음벽 전면 형상에 의한 반사음의 영향을 분석하여 반사형 방음벽을 최적화하여 반사음의 영향을 최소화 하고자 하였다. 방음벽 전면에 두께가 다른 블록을 설치하고 일반 반사형 방음벽의 소음 반사 효과와 비교한 결과, 일반 반사형 투명 방음벽에 비하여 0.9~1.5 dB(A)의 소음저감 효과가 있었다. 또한 반사음이 증가 또는 감소하는 공간적 영역이 블록의 두께에 따라 변화하는 것을 알 수 있었다. 이러한 현상은 방음벽 전면 형상에 따라 소음의 집중 및 확산분포가 다양하게 변화하는 것을 나타내며 방음벽을 최적화하는 기술의 가능성을 보여주는 결과라고 판단 하였다.

• 한국건설관리학회논문집
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• 제14권4호
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• pp.55-64
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• 2013

온실가스 에너지 목표관리제가 시행됨에 따라, 해당 사업장은 2020년까지 온실가스 배출 전망치 대비 30% 이상을 의무적으로 감축해야 한다. 에너지소비의 큰 비중을 차지하는 대학교 부문 역시 온실가스 감축이 요구됨에도 불구하고, 교육기관의 특성 상 에너지 절감에 투자할 수 있는 예산은 한정적이므로 고가의 대응책 적용에는 한계가 따른다. 따라서 본 연구는 서울대학교 관악캠퍼스를 대상으로 실 레벨에서 쉽게 적용 가능한 저가의 에너지감축 방안을 도출하고, 이를 통한 최대감축잠재량을 산정하는 사례연구를 목적으로 한다. 먼저, 관악캠퍼스 내 표본이 될 11개 용도의 실을 뽑아 1월 1일부터 7월 31일까지 에너지소비량을 매일 실측하였고, 실별 전력기기 계수 조사를 통해 실용도별 표준모형을 구축하였으며, 사용자 인터뷰와 설문 및 행정조사를 통해 전력소비패턴을 분석함으로써 실용도 표준모형 기반의 기기별 소비전력량을 산출하였다. 이를 기반으로, 32개의 감축기술 및 실천프로그램을 도출하여 실용도 표준모형에 적용하고 각 프로그램별 최대감축비율을 기기별 소비전력량에 곱해 기기별 최대감축량을 유도함으로써, 실별 월별 최대감축량과 관악캠퍼스 최대감축잠재량을 산정하였다. 그 결과, 본 연구가 제안한 감축기술 및 실천프로그램의 적용 시 1월부터 7월까지 약 $5,311tCO_2$-eq 즉 동일기간 관악캠퍼스 전체 에너지 사용량의 12.66%에 해당되는 양을 감축할 수 있으며, 2016년까지 서울대학교 필요감축량의 24.48%를 감축할 수 있는 것으로 조사되었다.

• 한국의상디자인학회지
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• 제16권4호
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• pp.189-203
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• 2014

In this study, Creative motifs using face composition of Jogakbo and Knot Symbol were developed, and applied to traditional Baeja of Joseon Dynasty to develop design contents of traditional clothes. As for study method, 7 motifs of new formative image that integrates traditional beauty and contemporary sense were developed by applying Knot Symbols and face compositions of Jogakbo with the use of Adobe Illustrator CS6 and Adobe Photoshop CS6 vector graphic software. The motifs were designed in contemporary image in face compositions like rectangle pattern, triangle pattern, dual rectangle pattern, vertical and horizontal pattern, pinwheel pattern, gojunmun pattern and free pattern by involving various changes like repetition, rotation, reduction, expansion and decomposition and using the colors used in the Jogakbo. It is desired that through this study, traditional Baeja may develop to bear traditional and contemporary image so that our traditional clothes design may become global. Also it is anticipated that this study will contribute to development of culture products of Hanbok like Jeogori, pants and skirt that require change of design in the global era while maintaining traditional beauty to appeal to the emotions of world citizens.

• 한국산업융합학회 논문집
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• 제22권1호
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• pp.47-54
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• 2019

An experimental study was conducted on the wear and friction responses in sliding tests of a micro-textured surface on laser pattern (LP) steel as reduction gear material in electric guided vehicle. In this research, the friction characteristics of laser pattern steel under different micro texture density conditions were investigated. The friction tests were carried out at sliding speeds of 0.06 m/s to 0.34 m/s and at normal loads of 2 to 10 N. Photolithography method was used to create the dimples for surface texturing purpose. Four different specimens having different dimple densities of 10%, 12.5%, 15%, and 20% were observed respectively. In this research, friction conditions as shown in Stribeck curve were investigated. Furthermore, the microscopic surface was observed using scanning electron microscope. It was found that the dimple density had a significant role on the friction characteristics of laser pattern steel conditioned as reduction gear material in an agricultural vehicle. The duty number showed that the friction condition was hydrodynamic regime. The best performance was obtained from 12.5% dimple density with lowest friction coefficient achieved at 0.018771 under the velocity of 0.34 m/s and 10N load.

• 유통과학연구
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• 제13권6호
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• pp.17-23
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• 2015

Purpose - Transnational corporations (TNCs) have influenced drastic changes (financial services, manufacturing, labor, technology transfer) in Central Eastern Europe (CEE). This paper examines the indirect changes in the CEE pattern of industrial development and market distribution. Research design, data, and methodology - Over 25 years, neighboring (or rival) countries competed to attract TNCs as a double-edged strategy for privatization and debt reduction. Through their experience attracting foreign direct investment (FDI), many countries started to reflect aspects of national capitalism. Countries also began to realize in 2010 that TNCs sought to enter markets with more favorable conditions for export-oriented manufacturing. Results - The analysis reveals that TNC investment strategies were aimed at eliminating local competition to acquire industrial "brown fields" to convert into "green fields." CEE countries have since strengthened their national systems and the support of large-scale state-owned enterprises and small and medium-sized start-up enterprises. Conclusions - CEE has changed based on industrial development and a regional structure of TNC market distribution and associated government policies. The pattern toward flexible markets gives countries the ability to further their economies.

• 전기학회논문지
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• 제59권7호
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• pp.1340-1345
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• 2010

FRC(Frame Rate Control) has been applied to the monitor and TV product as part of cost-saving in many flat panel display manufacturers. As FRC can represent the same number of gray scale level with bits of a smaller amount than bits of the input image data, it is widely used. However, FRC causes visual artifacts by using repeatedly pre-designed the FRC unit size of block pattern in display devices. Therefore, this paper analyzes the cause of the visual artifacts. And in order to improve them, it proposed the pattern arrangement of FRC unit blocks through frame rolling method as analytic solution for the first time. So, we could embody causes of FRC noise. Using the proposed structure, more robust pattern to FRC noise will be designed.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2007년도 하계종합학술대회 논문집
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• pp.79-80
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• 2007

In this paper, it tried to observe the relationship of radiation pattern and the polarization of the PCB. First, through the PCB trace structure analysis which is various it leads, it analyzes the feature of the DM/CM and provides the interrelation of far-field radiation pattern and the D/V polarization. Also, like this interrelation it leads, it proposes the PCB pattern plan for a decreasing of EMI.

• Journal of Advanced Marine Engineering and Technology
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• 제22권4호
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• pp.505-514
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• 1998

Flow pattern of air-water two phase flow depends on the conditions of pressure void fraction and channel geometry. We classify the flow pattern by measuring the output signal of the conductivity probe. under the classified flow pattern we mount a visualization equipment on the test section and take pictures. We vary the concentration of pure solvent and polymer to measure local void fraction. We know that the maximum point position of local void fraction distribution move from the center of the pipe to the wall of the pipe as JSL increase when JSA is constant in two phase flow. But we find that the maximum point position of local void friction move from the wal of the pipe to the center of the pipe when polymer concentration increase.

• 전자공학회논문지A
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• 제30A권1호
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• pp.8-15
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• 1993

A concrete disign of memory circuit is presented aiming at the application of sliding diagonal test patterns. A modification of sliding diagonal test pattern includes the complexity reduction from O(n$^{32}$) to O(n) using parallel test memory concept. The control circuit design was based on delay-element, and verified via logic and circuit simulation. Area overhead was evaluated based on physical layout using a 0.7 micron design rule resulting in about 1% area increase for a typical 16Mbit DRAM.