• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.506-508
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• 2005

In general, organic TFTs are comprised of four components: gate electrode, gate dielectric, organic active semiconductor layer, and source and drain contacts. The TFT current, in turn, is typically determined by channel length and width, carrier field effect mobility, gate dielectric thickness and permittivity, contact resistance, and biasing conditions. More recently, a number of techniques and processes have been introduced to the fabrication of OTFT circuits and displays that aim specifically at reduced fabrication cost. These include microcontact printing for the patterning of metals and dielectrics, the use of photochemically patterned insulating and conducting films, and inkjet printing for the selective deposition of contacts and interconnect pattern. In the fabrication of organic TFTs, microcontact printing has been used to pattern gate electrodes, gate dielectrics, and source and drain contacts with sufficient yield to allow the fabrication of transistors. We were fabricated a pentacene OTFTs on flexible PEN film. Au/Cr was used for the gate electrode, parylene-c was deposited as the gate dielectric, and Au/Cr was chosen for the source and drain contacts; were all deposited by ion-beam sputtering and patterned by microcontact printing and lift-off process. Prior to the deposition of the organic active layer, the gate dielectric surface was treated with octadecyltrichlorosilane(OTS) from the vapor phase. To complete the device, pentacene was deposited by thermal evaporation and patterned using a parylene-c layer. The device was shown that the carrier field effect mobility, the threshold voltage, the subthreshold slope, and the on/off current ratio were improved.

• 화훼연구
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• 제16권1호
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• pp.76-84
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• 2008

황색 꽃의 압화 후의 변색의 원인이 무엇인지를 모색하기 위해 나리, 온시디움, 장미, 튤립, 금어초, 카네이션, 프리지아, 칼라, 거베라, 해바라기와 라넌큘러스 황색 절화 11종을 식물재료로 사용하였다. 이들 식물 재료의 꽃잎의 특성과 화색소를 분석하고 압화 후의 변색 정도와의 상호 관련성을 검토하였다. 꽃잎 두께, 꽃잎의 장폭비, 그리고 꽃잎의 수분함량은 압화의 변색에 크게 영향을 미치지 않았다. 카로티노이드에 의해 황색이 발현되는 종은 나리, 온시디움, 장미와 튤립이었으며, 플라보노이드에 의해 황색이 발현되는 종은 금어초, 카네이션, 프리지아와 칼라였으며, 카로티노이드와 플라보노이드가 공존하면서 황색이 발현되는 종은 거베라, 해바라기와 라넌큘러스였다. 카로티노이드가 단독이거나 플라보노이드와 공존하거나 상관없이 카로티노이드에 의해 황색이 발현되는 경우는 압화의 변색 정도가 심했다. 그러나 플라보노이드에 의해 황색이 발현되는 종은 거의 변색 되지 않았다. 암처리 한 압화는 거의 변색되지 않았으나 광처리 한 것은 변색의 정도가 심했다.

• Steel and Composite Structures
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• 제10권2호
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• pp.187-205
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• 2010

The existing CFT columns present the deterioration in confining effect after the yield of steel tube, local buckling and the deterioration in load capacity. If lateral load such as earthquake load is applied to CFT columns, strong shearing force and moment are generated at the lower part of the columns and local buckling appears at the column. In this study, axial compression test and beam-column test were conducted for existing CFT square column specimens and those reinforced with carbon fiber sheets (CFS). The variables for axial compression test were width-thickness ratio and the number of CFS layers and those for beamcolumn test were concrete strength and the number of CFS layers. The results of the compression test showed that local buckling was delayed and maximum load capacity improved slightly as the number of layers increased. The specimens' ductility capacity improved due to the additional confinement by carbon fiber sheets which delayed local buckling. In the beam-column test, maximum load capacity improved slightly as the number of CFS layers increased. However, ductility capacity improved greatly as the increased number of CFS layers delayed the local buckling at the lower part of the columns. It was observed that the CFT structure reinforced with carbon fiber sheets controlled the local buckling at columns and thus improved seismic performance. Consequently, it was deduced that the confinement of CFT columns by carbon fiber sheets suggested in this study would be widely used for reinforcing CFT columns.

• Steel and Composite Structures
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• 제31권6호
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• pp.541-558
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• 2019

In Special Concentrically Braced Frames (SCBFs), vertical and horizontal components of the brace force must be resisted by column and beam, respectively but normal force component existing at the gusset plate-to-column and beam interfaces, creates out-of-plane action making distortion in column and beam faces adjacent to the gusset plate. It is a main concern in Hollow Structural Section (HSS) columns and beams where their webs and gusset plate are not in the same plane. In this paper, a new gusset plate passing through the HSS columns and beams, named as through gusset plate, is proposed to study the force transfer mechanism in such gusset plates of SCBFs compared to the case with conventional gusset plates. For this purpose, twelve SCBFs with diagonal brace and HSS columns and twelve SCBFs with chevron brace and HSS columns and beams are considered. For each frame, two cases are considered, one with through gusset plates and the other with conventional ones. Based on numerical results, using through gusset plates prevents distortion and out-of-plane deformation at HSS column and beam faces adjacent to the gusset plate helping the entire column and beam cross-sections to resist respectively vertical and horizontal components of the brace force. Moreover, its application increases energy dissipation, lateral stiffness and strength around 28%, 40% and 32%, respectively, improving connection behavior and raising the resistance of the normal force components at the gusset plate-to-HSS column and beam interfaces to approximately 4 and 3.5 times, respectively. Finally, using such through gusset plates leads to better structural performance particularly for HSS columns and beams with larger width-to-thickness ratio elements.

• 한국구조물진단유지관리공학회 논문집
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• 제23권1호
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• pp.36-44
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• 2019

본 연구의 목적은 강 - PC 복합모듈 골조를 구성하는 프레스 성형된 비대칭 기둥과 보 접합부의 구조적 성능을 평가하는 것이다. 모듈러 골조를 구성하는 대부분의 접합부는 폐쇄형의 사각형 강재 기둥 단면을 주로 사용한다. 폐쇄형의 기둥 단면을 사용한 기둥-보 접합부는 시공성을 감소시키고 내화성을 확보하는데 어려움이 있다. 이러한 단점을 극복하기 위하여 강판을 프레스로 성형하여 비대칭 개방형 단면 내에 콘크리트를 충진하는 것이다. 프레스 성형된 비대칭 기둥-보 접합부의 구조적 성능을 조사하기 위해 총 4개의 실험체를 제작하였다. 실험결과, 비대칭 기둥의 구조적 성능과 거동이 비대칭 기둥 단면이 합성되는지 또는 기둥의 폭-두께 비율에 따라 달라지는지를 보여주었다. 프레스 성형된 비대칭 기둥-보 접합부의 구조적 성능은 실험결과와 이론식을 비교하여 평가하였다.

• 한국의상디자인학회지
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• 제21권3호
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• pp.1-11
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• 2019

This study examined the cause of the phenomenon of shrinkage in machine-embroidered fabrics, specifically those made of thin and pliable fabrics. Four woven fabrics and two knitted fabrics were selected as samples for analysis. The fabrics selected were silk organza, flax linen, polyester chiffon, cotton batiste, polyester raschel mesh, and cotton jersey. The thickness and drapability of the fabrics were observed and the shrinkage of the various types of embroidered fabrics produced using satin & step stitch techniques were measured. Moreover, the correlation between the shrinkage of the machine-embroidered fabrics and the drapability of the original fabrics was analyzed. Also, the colorfastness of six embroidery yarns was determined. The results of the study are as follows: first, the shrinkage of machine-embroidered fabrics increased at a greater rate than in embroidered knitted fabrics as compared to rates in embroidered woven fabrics. Moreover, in terms of stitch techniques, there was a greater shrinkage rate when satin stitch was applied compared to step stitch. Second, the shrinkage rate of machine-embroidered fabrics decreased when a stabilizer was fused onto the fabric. The shrinkage rate also decreased for fabrics when fused with paper stabilizer compared to those without it, and the rate decreased at a greater amount with paper stabilizer as compared to alginate film. Third, since there was a strong correlation between the shrinkage rate of the embroidered fabric and the drapability ratio of the original fabric, it was generally the case that the more pliable the fabric was, the greater the shrinkage rate was when the fabric was embroidered. Fourth, while the embroidery yarns mainly used in machine-embroidery presented an overall excellent level of colorfastness, there was slight color migration of level 4 to level 5 when using viscose rayon.

• 한국지반공학회논문집
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• 제26권7호
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• pp.59-70
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• 2010

대상지역 내 중금속 오염농경지 복원을 위해 설계된 안정화 공법에 대한 현장 적용성을 검토하기 위해 현장실증시험을 수행하였다. 대상오염 농경지에 처리구들을 설치하여 오염토양만을 채운 무처리구를 제외한 각 처리구에 중금속 안정화 재료로 선정된 석회석과 산업부산물인 제강슬래그를 각각의 혼합비로 채운 후, 관측기간동안 처리구 내 토양을 채취하여 이화학특성, 중금속농도(Cu, Cd, Pb, Zn, As) 그리고 중금속 분획특성 등을 분석하여 그 특성을 비교하였으며, 그 결과를 수록하였다.

• Computers and Concrete
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• 제32권4호
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• pp.351-363
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• 2023

Reducing the self-weight of reinforced concrete structures problem is discussed in this paper by using two types of self-weight reduction, the first is by using lightweight coarse aggregate (crushed brick) and the second is by using styropor block. Experimental and Numerical studies are conducted on (LWAC) lightweight aggregate reinforced concrete slabs, having styropor blocks with various sizes of blocks and the ratio of shear span to the effective depth (a/d). The experimental part included testing eleven lightweight concrete one-way simply supported slabs, comprising three as reference slabs (solid slabs) and eight as styropor block slabs (SBS) with a total reduction in cross-sectional area of (43.3% and 49.7%) were considered. The holes were formed by placing styropor at the ineffective concrete zones in resisting the tensile stresses. The length, width, and thickness of specimen dimensions were 1.1 m, 0.6 m, and 0.12 m respectively, except one specimen had a depth of 85 mm (which has a cross-sectional area equal to styropor block slab with a weight reduction of 49.7%). Two shear spans to effective depth ratios (a/d) of (3.125) for load case (A) and (a/d) of (2) for load case (B), (two-line monotonic loads) are considered. The test results showed under loading cases A and B (using minimum shear reinforcement and the reduction in cross-sectional area of styropor block slab by 29.1%) caused an increase in strength capacity by 60.4% and 54.6 % compared to the lightweight reference slab. Also, the best percentage of reduction in cross-sectional area is found to be 49.7%. Numerically, the computer program named (ANSYS) was used to study the behavior of these reinforced concrete slabs by using the finite element method. The results show acceptable agreement with the experimental test results. The average difference between experimental and numerical results is found to be (11.06%) in ultimate strength and (5.33%) in ultimate deflection.

• 한국산림과학회지
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• 제14권1호
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• pp.33-38
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• 1972

지리산산(智異山産) 참나무류(類)의 목섬유(木纖維) 변이(變移)를 알고져 신갈나무, 졸참나무 및 굴참나무 3수종(樹種)에 대(對)하여 수(髓)에서 부터 2년륜(年輪)씩 28년륜(年輪)까지 취(取)하여 그 변이(變移)를 조사(調査)한바 그 결과(結果)는 아래와 같다. 1. 목섬유장(木纖維長)의 범위(範圍)는 신갈나무는 $640{\sim}1,544{\mu}$(평균(平均) $1,142.3{\mu}$)이며 변이계수(變移係數)는 8~16%, 졸참나무는 $592{\sim}1,600{\mu}$(평균(平均) $1,179.6{\mu}$)이며 변이계수(變移係數)는 6~21%, 굴참나무는 $672{\sim}1,592{\mu}$ (평균(平均) $1,298.9{\mu}$)이며 변이계수(變異係數)는 2~15%으로 3 수종(樹種) 공(共)히 16년륜(年輪)까지 목섬유장(木纖維長)은 급격(急激)히 증가(增加)하고 이후(以後)는 약간의 변동(變動)이 있으나 거의 안정상태(安定狀態)를 유지 하였다. 2. 목섬유(木纖維) 폭(幅) 및 막후(膜厚)는 폭(幅)이 $7.6{\sim}10{\mu}$(평균(平均) $9.3{\mu}$)이였으며 막후(膜厚)는 $20{\sim}3.2{\mu}$(평균(平均) $2.6{\mu}$)으로 3수종(樹種) 공(共)히 연륜(年輪)이 증가(增加)함에 따라 서서히 증가(增加)하나 목섬유장(木纖維長)에 비(比)하면 극히 완만한 안정상태(安定狀態)의 변화(變化)를 보이고 있다. 3. 수종간(樹種間) 목섬유장(木纖維長) 차(差)를 알고져 유의성(有意性)을 검정(檢定)한바 유의차(有意差)가 없으므로 수종간(樹種間) 식별(識別)의 요인(要因)으로는 의의(意義)가 없다. 4. 지질(紙質)을 좌우(左右)하는 요소(要素) 즉(卽) 목섬유결합면적(木纖維結合面積), 룬켈 계수(係數) 및 유연계수(柔軟係數)를 산출(産出)한바 펄프재(材)로도 유용(有用)하다고 인정(認定)할 수 있겠다.

• 한국음향학회지
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• 제19권2호
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• pp.33-39
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• 2000

낮은 형상요소를 갖는 표면탄성파 대역통과 필터의 주파수 특성을 구현하기 위하여 35° Y-cut Quartz 표면에 빗살무늬 변환기를 형성시켜 모의실험을 수행하였으며, 전극재료로는 Al을 이용하였다. 이 모의실험에서 얻은 조건들로부터 필터를 설계하였으며, 필터의 입력단에는 apodization weighted형 빗살무늬 변환기를 이용하고, 출력단에는 withdrawal weighted형 빗살무늬 변환기로 필터를 구성하였다. 또한, 입·출력 빗살무늬 변환기의 전극 수는 리플의 영향을 최소화하기 위해 Kaiser-Bessel 창함수를 이용하였으며, 각각 2200쌍과 1000쌍으로 하였다. 그리고, 빗살무늬 변환기 전극의 폭은 6㎛, 간격은 5.75㎛ 및 두께는 표면탄성파 파장과의 비를 고려해 6000Å으로 할 때 최적의 결과를 얻을 수 있었으며, 구경은 임피던스 정합을 위해 2mm로 하였다. 제작한 표면탄성파 대역통과 필터의 중심주파수는 70MHz, 형상요소는 1.3이하, 1.5dB에서의 통과 대역은 1.3MHz, 저지대역은 -45dB, 삽입손실은 19dB, 통과 대역폭 내의 리플은 1dB정도로 측정되었다. 따라서, 제작한 필터의 주파수 응답과 특성은 설계조건과 잘 일치하였다.