• Elastomers and Composites
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• v.40 no.1
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• pp.37-44
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• 2005

Novel polyurethanes containing no mesogenic unit were synthesized by the polyaddition reaction of para-type diisocyanates such as 2,5-tolylene diisocyanate (2,5-TDI) or 1,4-phenylene diisocyanate (1,4-PDI) with 2,6-bis(${\omega}$-hydroxyalkoxy)naphthalene (BHNm; m= 5, 6, 8, 11). Intrinsic viscosities of the polymers were in the range of 0.28-0.43 dL/g. The thermal properties of these polymers were studied by differential scanning calorimetry and polarizing microscopy. Polyurethanes prepared from BHNm and 2,5-TDI haying methyl substituent on the phenylene unit exhibited monotropic liquid crystallinity. However, in the series of polyurethanes prepared from 1,4-PDI and BHNm, no explicit mesomorphic behavior was observed by differential scanning calorimetry and polarizing microscopy.

• Economic and Environmental Geology
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• v.47 no.1
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• pp.29-38
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• 2014

Recently developed illite-age-analysis (IAA) approach has been applied to determine the multiple events for the Singal and Wangsukcheon faults in the Chugaryeong fault belt, Korea. Fault reactivated events during Late Cretaceous to Paleogene events($69.2{\pm}0.3$ Ma and $27.2{\pm}0.5$ Ma) for the Singal fault and of $75.4{\pm}0.8$ Ma for the Wangsukcheon fault were determined by combined approach of the optimized illite-polytype quantification and the K-Ar age-dating of clay fractions separated from the fault clays. These absolute geochronological determinations of the multiple tectonic events recorded in the Chugaryeong fault belt are crucial to establish the tectonic evolution of the Korean Peninsula since Late Cretaceous.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05b
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• pp.46-49
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• 2001

To estimate the influence of electrical properties due to the poly back seal(PBS). we were investigated defect density in surface by deposition thickness and breakdown voltage in specimens. Deposition thickness of specimen is prepared from 7,000[$\AA$] to 13,000[$\AA$], respectively. From the results, it is confirmed that PBS deposition thickness of 10,000[$\AA$] among the specimen is decreased defect density by contribution of the gettering effect.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.10
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• pp.451-457
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• 2003

The silicon wafer is stable status at room temperature, but it is weak at high temperatures which is necessary for it to be fabricated into a power semiconductor device. During thermal diffusion processing, a high temperature produces a variety thermal stress to the wafer, resulting in device failure mode which can cause unwanted oxide charge or some defect. This disrupts the silicon crystal structure and permanently degrades the electrical and physical characteristics of the wafer. In this paper, the electrical characteristics of a single oxide layer due to high temperature diffusion process, wafer resistivity and thickness of polyback was researched. The oxide quality was examined through capacitance-voltage characteristics, defect density and BMD(Bulk Micro Defect) density. It will describe the capacitance-voltage characteristics of the single oxide layer by semiconductor process and device simulation.

• The Journal of Engineering Geology
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• v.1 no.1
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• pp.2-10
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• 1991

Some geotechnical considerations might be suggested to the construction performance from the school and the housing projects in Tripoli sub-region, Libya. The subsurface informations were compiled from the site investigation reports, for which more than 700 borings and lots of laboratory test had been conducted from 1984 to 1986. Most subsurface of 10 meter depth in the Jafara plain consists of medium dense silty sand. Some ground in the plain have poor top soil with interbedded calcarenite or limestone. The shallow subsurface is found to be very poor soil in the southern mountain range. Weak soil is hardly found except in the sabkha area. In general, natural silty sand layer may have a presumed bearing capacity of more than 150kN/$m^2$, where spread or strip footing is applied. Proper fine aggregate and natural coarse one are restricted in Tripoli sub-region. Coarse aggregate is generally supplied from the dolomite quarry.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.4
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• pp.14-22
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• 2022

To reduce the weight of the car and ensure the safety of the driver while driving, the existing 440 MPa-class mounting bracket was treated at 590MPa to improve collision safety and secure the weight of the vehicle body. The following conclusions were drawn from the tensile test, forming analysis, and springback prediction. In the formability and springback analyses using FLD, it could be confirmed that bending was an essential process because the formability and flatness were much better when bending was added than when bending was not applied. Based on the research results, it was deduced that the mold design was necessary so that the molding was carried out at a strain rate of 20% or less for stable molding.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.331-332
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• 2003

Poly(ethylene terephthalate) (PET)는 물리적, 기계적 성질이 우수한 엔지니어링 플라스틱의 하나로 섬유, 필름 및 각종 산업용 소재로 가장 널리 이용되고 있는 고분자 중의 하나이다. 그러나 PET 자체의 성질만으로 고기능성 소재로의 다양한 요구를 충족시키기에는 한계가 있어 PET의 벤젠고리 대신에 나프탈렌 고리로 치환하거나 제 3성분의 2가 알코올을 첨가하여 PET보다 유리전이 온도와 용융 온도가 높고 형태안정성 및 기계적 물성이 우수한 고분자의 개발에 관한 연구가 다수 이루어져 왔다.$^{1.2}$ (중략)

• The Science & Technology
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• v.32 no.2 s.357
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• pp.86-87
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• 1999

98년 10월 27일부터 3일간 미국 세인트루이스에서 제13차 미국정밀학회 연례학술회의가 열렸다. 유럽ㆍ한국ㆍ일본 등 각국에서 3백여명이 참석한 이번 학술대회에서 강원대 장인배교수 연구팀은 자기부상을 이용한 초정밀 직선운동 테이블에 대한 연구를 4년째 발표하여 많은 찬사를 받았다. 이번 학회는 렌즈가공을 주 대상으로 한 연삭 및 폴리싱 등의 가공방법에 대한 연구가 주종을 이루었다.

• The monthly packaging world
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• s.167
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• pp.146-153
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• 2007

국립수산물품질검사원은 수산물의 전근대적인 유통관행을 개선하기 위해 포장을 표준∙규격화하는 '수산물 표준규격 고시를 만들어 최근 고시했다. 이로 인해 1백 여종 이상의 포장규격이사용되는 등 천차만별이었던 수산물의 포장규격이 종류별로 통일될 것으로 보인다. 검사원은 고시에서 수산물의 표준거래 단위를 3kg, 5kg, 10kg, 15kg, 20kg으로 구분해 규정했고, 포장재질은 골판지 상자나 발포폴리에스틸렌 상자, 그물망 등을 사용하도록 했다. 해양수산부도 앞으로 수산물 규격상자를 만드는 업자들에게 표준규격을 따르도록 권장하고 수산물 표준 규격집을 만들어 어업인, 유통업자들에게 배포하는 한편 고등어 등 일부어종에 시범적으로 표준규격을 도입함으로써 표준규격이 확산될 수 있도록 할 방침이다. 본 고에서는 주요 내용을 살펴보도록 한다.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.10
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• pp.1054-1057
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• 2008