• 대한기계학회논문집A
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• 제40권8호
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• pp.693-701
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• 2016

본 논문에서는 파괴역학적 방법으로 노치 결함을 평가해 보았다. 인장 하중과 굽힘하중이 작용하는 중앙 균열, 모서리 균열 평판 구조물을 바탕으로 노치 크기를 달리하며 한계하중 및 에너지해방률을 유한요소 해석의 J-적분으로 도출하였다. 노치의 반경이 커짐에 따라 한계하중은 큰 변화가 없었으며, 에너지해방률는 커지는 양상을 보였다. 노치 반경에 따른 재료 파괴인성($J_{IC}$)측정을 위해 실험을 대신한 유한요소 연성파손 모사기법을 사용하였다. 그 결과 노치 크기 증가에 따른 에너지해방률 증가량 대비 파괴인성($J_{IC}$) 증가량이 더욱 큰 양상을 보였다. 이런 결과를 통해 노치 반경이 커질수록 균열 진전에 대한 저항성이 커진다는 사실을 알 수 있었다.

• 대한기계학회논문집A
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• 제25권2호
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• pp.250-263
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• 2001

The up and down speed of heddle frames that produce woven cloth by insertion of weft yarns between warp yarns has been increased recently much for productivity improvement, which induces higher inertial stresses and vibrations in the heddle frame. the heddle frame is required to reduce its mass because the heddle frame contributes the major portion of the stresses in the heddle frames during accelerating and decelerating. Conventional aluminum heddle frames have fatigue life of around 5 months at 550rpm due to their low fatigue flexural strength as well as low bending stiffness. In this work, since carbon/epoxy composite materials have high specific fatigue strength(S/p), high specific modulus(E/p), high damping capacity and sandwich construction results in lower deflections and higher buckling resistance, the sandwich structure composed of carbon/epoxy composite skins and polyurethane foam were employed for the high-speed heddle frame. The design map for the sandwich beams was accomplished to determine the optimum thickness and the stacking sequences for the heddle frames. Also the effects of the number of ribs on the stress of the heddle frame were investigated by FEM analyses. Finally, the high-speed heddle frames were manufactured with sandwich structures and the static and dynamic properties of the aluminum and the composite heddle frames were tested and compared with each other.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.278.1-278.1
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• 2014

Organic materials have been explored as the gate dielectric layers in thin film transistors (TFTs) of backplane devices for flexible display because of their inherent mechanical flexibility. However, those materials possess some disadvantages like low dielectric constant and thermal resistance, which might lead to high power consumption and instability. On the other hand, inorganic gate dielectrics show high dielectric constant despite their brittle property. In order to maintain advantages of both materials, it is essential to develop the alternative materials. In this work, we manufactured nanocomposite gate dielectrics composed of organic material and inorganic nanoparticle and integrated them into organic TFTs. For synthesis of nanocomposite gate dielectrics, polyimide (PI) was explored as the organic materials due to its superior thermal stability. Candidate nanoprticles (NPs) of halfnium oxide, titanium oxide and aluminium oxide were considered. In order to realize NP concentration dependent electrical characteristics, furthermore, we have synthesized the different types of nanocomposite gate dielectrics with varying ratio of each inorganic NPs. To analyze gate dielectric properties like the capacitance, metal-Insulator-metal (MIM) structures were prepared together with organic TFTs. The output and transfer characteristics of organic TFTs were monitored by using the semiconductor parameter analyzer (HP4145B), and capacitance and leakage current of MIM structures were measured by the LCR meter (B1500, Agilent). Effects of mechanical cyclic bending of 200,000 times and thermally heating at $400^{\circ}C$ for 1 hour were investigated to analyze mechanical and thermal stability of nanocomposite gate dielectrics. The results will be discussed in detail.

• 한국산학기술학회논문지
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• 제17권2호
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• pp.378-385
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• 2016

전기 분 배전반의 내부 회로 인 부스 바는 충전부의 노출로 인해 전기 사고의 원인이 되며 이로 인한 감전 사고와 단락 사고가 발생된다. 또한 동물 및 이물질 침투로 인한 전기 화재 사고가 발생되는 원인이 되기도 한다. 또한 확장이 불가능한 구조로 무리하게 연결하여 사용하므로 접촉 저항 증가 발생으로 과열 사고를 유발시키기도 하며, 절단과 절곡 등의 제조 공정상의 어려움을 가지고 있기 때문에 주문생산방식을 택할 수밖에 없는 현실이며, 긴급전기 사고 발생시 복구하는데 지연되는 원인이 되기도 한다. 본 논문에서는 이와 같은 문제점을 개선하기 위해서 분 배전반의 모선을 절단하여 개별 블록으로 절연 난연 케이스와 격벽 구조화로 안전성을 높여 모듈 블록화 하였으며, 확장성과 유연성을 구현하였으며, 쉽게 확장이 가능한 구조이며, 또한 쉽게 분 배전반을 조립할 수 있다는 것이며, 이와 같이 전기적 위험 요소를 제거한 전기 분 배전반의 내부 구조는 블록형 부스 바 구조를 가지고 메인차단기와 분기차단기간의 회로 형성 구현 방식의 분 배전반를 제안하고 공인시험기관의 시험을 통해 그 유용성을 입증 하였다.

• 공업화학
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• 제1권2호
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• pp.168-175
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• 1990

1, 2-Disubstituted imidazoline 화합물인 1-behenoylaminoethyl-1-glycidyl-2-heneicosylimidazolinium chloride(BHIC), 1-behen oylbis(aminoethyl)-1-glycidyl-2-heneicosylimidazolinium chloride(BBIC) 및 1-behenoyltris(aminoethyl)-1-glycidyl-2-heneicosylimidazolinium chloride(BTIC)로부터 유연제 원액인 BHICS, BBICS, BTICS를 각각 제조하여 아크릴섬유에 유연처리를 한 후 유연성, 평활성 및 대전방지성을 측정한 결과 유연제 모두 유연성과 평활성이 양호하였으며 약간의 대전방지성도 보유하였다. 또한 BBICS와 BTICS의 초기강연도는 5 grade, 5회 세탁후는 3~4 grade로 각각 나타나 내수성을 지닌 양호한 유연효과를 나타내었다. 아울러 처리온도에 따른 촉감의 내세탁성 및 pH 변화에 따른 촉감의 내세탁성 시험결과 등을 통하여 제조된 유연제가 내구성 유연제임을 입증하였다.

• 패션비즈니스
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• 제21권2호
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• pp.105-112
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• 2017

A string wallcovering is a kind of textile wallcovering which is made of cellulose fiber yarn laminated on base paper. Compared with normal paper or PVC wallpaper, a string wallcovering is preferred continually in the interior design market, as it is not only environmentally friendly but it also has less cost on mass production without the weaving process and has a natural visual effect, excellent functionality such as thermo keeping, permeability, sound absorption. However, in the dyeing process, it is not appropriate to use plenty of energy such as water, electricity, steam or chemicals considering the environmental trend and the government policy plenty of energy such as water, electricity, steam or chemicals. Currently, a string wallcovering is made of raw white yarn and padding with direct dye or pigment which includes toxic elements, especially the use of direct dye is restricted in a part of the developed country due to inclusion of azo. In this study, we researched dyeing based on cold pad batch dyeing of a string wallcovering with reactive dyestuff. The peel strength and bending depth test confirmed that the optimum adhesive type and spread amount improved the water resistance of the string wallcovering. Also, pad batch dyeing with optimum reactive dyestuff enhanced the color fastness to light and rubbing in dry and wet conditions. Additionally, for improvement of color fastness to rubbing in a wet condition, the additional treatment finishing without soaping process which is used water. The results of this study can be used as basic data for environmentally friendly and energy saving of the textile wallcovering.

• 한국도로학회논문집
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• 제14권1호
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• pp.17-24
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• 2012

본 연구에서는 다양한 실내시험을 통하여 국내에서 개발된 에폭시 아스팔트 혼합물의 공용성을 평가하였다. 최대입경 13mm의 밀입도 혼합물을 기초로 하여 아스팔트 바인더의 20% 또는 40%를 국산 및 일본산 에폭시 수지로 치환하여 4종류의 에폭시 아스팔트 혼합물의 배합 설계를 실시하였다. 에폭시 아스팔트의 가사시간이 에폭시 수지가 40% 사용한 경우 3시간, 20% 사용한 경우 6시간 정도임을 확인할 수 있었다. 휠트랙킹 시험, 간접인장 반복시험, 그리고 저온 휨 시험 결과 국산 및 일본산 에폭시 아스팔트 혼합물의 공용성이 일반 아스팔트 혼합물 보다 상당히 우수한 것으로 나타났다. 하지만 일부 에폭시 아스팔트 혼합물에서는 수분손상 가능성을 확인할 수 있었다. 또한 일본산 에폭시 아스팔트 혼합물과 국산 에폭시 아스팔트는 유사한 성능을 나타냈다. 또한 콘크리트 보수재로 개발한 국산 에폭시 아스팔트의 적합성을 평가하기 위하여 추가적으로 열팽창계수, 부착강도, 인장강도를 측정한 결과, 일반 콘크리트와의 부착력은 우수하고 인장강도는 유사한 것으로 나타났으나 열팽창계수는 5배정도 큰 것으로 나타났다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.491-491
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• 2011

Transparent and flexible electronic devices that are light-weight, unbreakable, low power consumption, optically transparent, and mechanical flexible possibly have great potential in new applications of digital gadgets. Potential applications include transparent displays, heads-up display, sensor, and artificial skin. Recent reports on transparent and flexible field-effect transistors (tf-FETs) have focused on improving mechanical properties, optical transmittance, and performances. Most of tf-FET devices were fabricated with transparent oxide semiconductors which mechanical flexibility is limited. And, there have been no reports of transparent and flexible all-organic tf-FETs fabricated with organic semiconductor channel, gate dielectric, gate electrode, source/drain electrode, and encapsulation for sensor applications. We present the first demonstration of transparent, flexible all-organic sensor based on multifunctional organic FETs with organic semiconductor channel, gate dielectric, and electrodes having a capability of sensing infrared (IR) radiation and mechanical strain. The key component of our device design is to integrate the poly(vinylidene fluoride-triflouroethylene) (P(VDF-TrFE) co-polymer directly into transparent and flexible OFETs as a multi-functional dielectric layer, which has both piezoelectric and pyroelectric properties. The P(VDF-TrFE) co-polumer gate dielectric has a high sensitivity to the wavelength regime over 800 nm. In particular, wavelength variations of P(VDF-TrFE) molecules coincide with wavelength range of IR radiation from human body (7000 nm ~14000 nm) so that the devices are highly sensitive with IR radiation of human body. Devices were examined by measuring IR light response at different powers. After that, we continued to measure IR response under various bending radius. AC (alternating current) gate biasing method was used to separate the response of direct pyroelectric gate dielectric and other electrical parameters such as mobility, capacitance, and contact resistance. Experiment results demonstrate that the tf-OTFT with high sensitivity to IR radiation can be applied for IR sensors.

• 한국구조물진단유지관리공학회 논문집
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• 제15권4호
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• pp.99-106
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• 2011

본 연구는 LB-DECK의 합성 전과 후 적절한 설계방법을 적용하기 위하여 PBD의 기초 개념에 근거하여 성능향상을 위한 연구를 수행하였다. 그 결과, 합성 전 폴리머 콘크리트를 활용함에 따라 휨 인장강도를 증가시켜 미세균열을 감소시킬 수 있으며, 심미적인 효과를 기대할 수 있고, 낮은 침투성으로 인하여 내구성을 향상시키고, 이에 따른 피복두께를 감소시킬 수 있을 것으로 평가되었다. 또한 합성 후 경험적 설계법을 적용한 LB-DECK 바닥판은 일반적인 바닥판보다 하중 저항능력이 우수하여 안전성이 증가되며, 강도설계법 적용시와 달리 지간이 증가되어도 철근배근방법과 철근배근량이 일정하기 때문에 시공성과 경제성을 동시에 확보할 것으로 기대된다.

• 한국염색가공학회지
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• 제16권3호
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• pp.22-30
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• 2004

The polyester fabrics were treated with the chitosan with various solubility in optimized treatment condition. The treatment method was discussed to be a high functional finishing for the polyester fabric to obtain the high moisture absorption and anti-microorganism property by evaluating the effect of the chitosan purification method on the yield and anti-microorganism property of the chitosan. On the other hand, soluble polyurethane was added to the chitosan treatment solution and/or plasma pretreatment was done. The addition of soluble polyurethane give a high add-on ratio as well as a linen like effect of treated polyester fabric. The results were as follows: 1. In the treatment of polyester fabric by the chitosan solution, a soluble PU resin and low temperature plasma treatment were done to obtain high binding force between the fabrics and the chitosan. The add-on rate and the moisture absorption ratio of the fabrics treated with the chitosan-PU after treated with the plasma slightly increased more than those of the fabrics treated with the chitosan only. 2. Anti-static property of the fabrics treated with the chitosan decreased rapidly with increasing of the chitosan concentration. The washing fastness of the fabrics treated with the chitosan-PU after treated with the plasma was better than those of the fabrics treated with chitosan only. The wrinkle resistance of the treated fabrics decreased constantly with the concentration of the chitosan. The bending rigidity of the treated fabrics increased greatly. On the treatment of polyester fabric under optimum condition, the microorganism reduction rate kept above 90％ after 10times launderings. 3. As the polyester fabrics which has flat yam was used as a weft yams were treated with the chitosan-PU as give a functional finishing effects such as durability, moisture absorption, anti-static and anti- microorganism property. Treated polyester fabric showed a good functional finishing effect and a linen like property.