• 감성과학
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• 제10권2호
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• pp.169-175
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• 2007

본 연구에서는 국내 7개회사와 중국과 대만의 각각 2개회사에서 만든 PET POY 사(絲)의 섬도, 인장역학특성 그리고 열 수축특성 등의 물성편차에 대해 연구하였다. 이를 위해 준비된 시료로서는 239d/96f 중국사와 255d/48f의 국내사를 시료로 사용하였으며 120d 굵기의 중국사와 대만사 두 가지를 국내 6개 기업에서 만들어진 사(絲)와 또한 각각 비교하였다. 그리고 섬도, 인장역학특성 그리고 습열과 건열 수축률 등과 같은 물성 실험은 원사 케이크 내의 사(絲), 50,000m를 1개 층으로 각각 나누어 각각의 층별로 측정하였으며 이들 원사 케이크 내외층의 물성의 편차를 국내 외 원사별로 측정 분석하였다. 이들 결과들은 국내 중소 제직, 사가공 기업에게 고부가가치 고감성 소재를 개발하는데 필요한 기초물성 데이터를 제공해주는 데 큰 의의를 가진다.

• 대한화학회지
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• 제54권6호
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• pp.749-754
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• 2010

본 연구에서는 IR과 CR의 블렌딩을 통하여 물성 개선 및 내구 성능 개선을 목적으로 IR/CR의 비율을 다양하게 블렌딩하여 제조한 고무시료의 가교 특성, 물성 변화, Morphology의 변화 및 화학적 특성을 조사하였다. 한편으로 블렌딩 된 고무에 다양한 조건으로 염소 표면처리를 하였을 때 고무시료의 Morphology를 관찰하고 마찰 시험을 통해 염소의 표면처리가 마찰계수에 미치는 영향을 조사하였다. 고무의 가교특성에서는 CR의 함량이 증가할수록 가교 속도가 감소하였으나 가교밀도는 일정하였고,경도, 모듈러스가 증가하였는데 이것은 가교특성의 변화와 밀접한 관계가 있으며, 가교 반응의 활성화에 의한 결정화 영향으로 기계적 강도가 증가하는 것으로 나타났다. 노화 후 물성 변화는 IR/CR Blend가 상호 기계적 물성의 단점을 보완하여 노화에 의한 물성 변화를 감소시키는 역할을 하는 것으로 나타났다. 염소 표면처리 한 시료의 노화 전, 후 상태물성의 변화는 감소하였다. 현미경 사진 관찰 결과 CR 함량 증가에 따라 표면 분산도가 증가함을 알 수 있었다. 염소 표면처리된 고무의 표면은 일정한 방향으로 균일하게 표면처리되었고 매끄러움과 광택이 증가하였다. 고무 표면의 개질 정도는 표면염소잔류량으로 확인할 수 있었으며, 마찰계수는 고무와 결합된 염소함량에 의존하는 것으로 나타났다. CR 함량이 10 - 40 phr까지는 표면처리 초기단계에서 마찰계수가 급격히 감소하였으나, 처리용액의 염소농도가 증가할수록 마찰계수의 감소는 둔화되었고, CR 함량이 50 phr에서는 처리용액의 염소농도 변화에 따라 마찰계수의 감소가 둔화되었다.

• 한국의류산업학회지
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• 제20권1호
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• pp.93-100
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• 2018

This study comparatively analyzed the changes in the dimensional stability and the mechanical properties of stretch knit fabrics associated with washings conditions in order to determine the most appropriate washing method. Polyester and spandex knit fabrics were washed 25 cycles with nine washing condition profiles that controled detergent, hardness. temperature and RPM. The knit fabrics with repeated washings were evaluated by dimensional stability and measured by the KES-FB system. Polyester and spandex fibers have good chemical resistance. However, the changes in the dimensional stability and the mechanical properties were observed in washed knit fabrics. After repeated washings, the knit fabrics washed in an alkali or neutral detergent had good dimensional stability compared with the knit fabric washed in functional detergent. The washed knit fabrics were extended, stiff, rough, and had a smaller volume. The changes were the result of the rearrange of polyester fibers which twisted around spandex core and chemical interactions involving the detergent and the physical and mechanical forces of washing. Especially, using an alkali detergent resulted in increased stiffness and roughness of the knit fabric. In conclusion, the washing in water with low hardness and a neutral detergent can minimize the changes in dimensional stability and mechanical properties of polyester and spandex knit fabric.

• Journal of the Korean Wood Science and Technology
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• 제25권4호
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• pp.29-38
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• 1997

The effect and control of wood property of reconstituted composite panels for improved board properties by wood-waste materials and development of combination method for heterogeneous materials have been of interest to the wood science researchers. The purpose of this study is to consider the properties in relation to hot pressing conditions and to develope the optimum hot pressing condition with waste wood and waste tire for the manufacturing of composite boards. The study of composite boards for recycling of wood and waste tire is nothing up to the present. Physical and mechanical properties such as specific gravity, moisture content, swelling coefficient, modulus of rupture and modulus of elasticity in bending test were studied. The condition of 3-stage press time for the lowest moisture content of composite board was $4{\rightarrow}3{\rightarrow}3$ minutes. Specific gravity of composite panels was affected mainly by the amount of rubber chip. Because of the low rigidity and high elasticity in rubber chip, it is considered the composite panel was adequate material in the place of compression load, but not bending load. Therefore, it was concluded that a use of rubber-based wood composite panel is proper to the interior materials such as floor a room than exterior materials. From the test results, the most optimum hot pressing conditions were $4{\rightarrow}3{\rightarrow}3$ minutes for 3-stage press time and $45{\rightarrow}20{\rightarrow}5kg/cm^2$ for 3-stage press pressure. The rubber-based wood composite panel was very excellent in elasticity by combination of rubber chip in comparison with existing other wood-based materials. Therefore, it was considered that rubber-based wood composites can be applicable to every interior materials such as floor a room and will be expected to effective reuse and recycle of waste tires and wood-waste materials, and will be contribute to protection of environment pollution in earth.

• 한국가스학회지
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• 제8권2호
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• pp.1-7
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• 2004

경질폴리우레탄 폼 제조 시 water, HFC-365mfc, HFC-245fa, HCFC-l4lb, CFC-11, n-pentane을 사용하여 단일발포제가 폼의 물성에 미치는 영향을 알아보고, HFC-365mtc 를 주 발포제로 사용하고 water, HFC-245fa, HCFC-l4lb, CFC-11, n-Pentane을 보조발포제로 사용하여 혼합 발포제(co-blowing agent)가 폼의 물성에 미치는 영향을 고찰하였다. 단일 발포제의 영향에서 압축강도는 물의 경우가 3.83kg/m^2으로 가장 큰 값을 나타내었으며 Scanning electron/microscopy(SEM)분석 결과 HFC-245fa와 HFC-365mfc의 경우가 기공분포 크기가 가장 작은 것으로 관찰이 되었다. 열전도도는 CFC-11, HFC-245fa와 HFC-365mfc의 경우가 낮은 열전도도 값을 보여서 폼의 열전도도는 기공크기와 발포제의 열전도도에 의존함을 알 수 있었다. 혼합 발포제의 영향에서는 HFC-245fa를 $30mo1e\%$로 사용한 경우가 가장 높은 기계적 물성 값을 나타내었으며 이는 SEM 분석 결과, HFC-245fa를 보조 발포제로 사용한 경우가 가장 작은 기공분포크기를 나타내었기 때문이었다. 혼합 발포제의 영향에서도 폼의 열전도도는 기공크기와 발포제의 열전도도에 의존함을 확인 할 수 있었다.

• 펄프종이기술
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• 제45권3호
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• pp.1-8
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• 2013

Hanji has been used mainly for preservation paper because of superior mechanical properties. However, it was not used in printing for inkjet and laser printer-printed letters. In this study, machine-made Hanji was prepared with five different contents of paper mulberry 20, 40, 60, 80 and 100% and managed by same pressure calendering. By increasing of paper mulberry contents, tearing index and folding endurance of machine-made Hanji increased because of increased fiber-to-fiber bonding. Printability property of machine-made Hanji improved by decreasing of paper mulberry contents. After 20 hours accelerated aging, the initial folding endurance of machine-made Hanji was reduced by approximately one-fourth degree. Between 40 and 100% contents of paper mulberry was showed similar levels about preservation property. The machine-made Hanji of paper mulberry 60% content was suitable for permanence and printability properties using preservation paper and printer-printed letters.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제18권2호
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• pp.77-105
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• 2014

Medical imaging techniques have evolved to expand our ability to visualize new contrast information of electrical, optical, and mechanical properties of tissues in the human body using noninvasive measurement methods. In particular, electrical tissue property imaging techniques have received considerable attention for the last few decades since electrical properties of biological tissues and organs change with their physiological functions and pathological states. We can express the electrical tissue properties as the frequency-dependent admittivity, which can be measured in a macroscopic scale by assessing the relation between the time-harmonic electric field and current density. The main issue is to reconstruct spectroscopic admittivity images from 10 Hz to 1 MHz, for example, with reasonably high spatial and temporal resolutions. It requires a solution of a nonlinear inverse problem involving Maxwell's equations. To solve the inverse problem with practical significance, we need deep knowledge on its mathematical formulation of underlying physical phenomena, implementation of image reconstruction algorithms, and practical limitations associated with the measurement sensitivity, specificity, noise, and data acquisition time. This paper discusses a number of issues in electrical tissue property imaging modalities and their future directions.

• 한국인쇄학회지
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• 제29권3호
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• pp.97-104
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• 2011

The storing ability of information of optical disks directly depends on the physical property of recording unit cells. It means that the degradation of optical disks ultimately causes the loss of the physical and chemical properties of recording unit cells and leads also information, too. We investigated the degradation and life time of optical disks which tell us the longevity of the preservation of information. Optical disks were aged using the accelerated aging system and studied by optical reflectivity spectroscopy and atomic force microscopy(AFM), and the preservation environment of electronic media in National central library of Korea also were analysed. Results show that the double reflective coated optical disks have good preservation of recording information but revealed some deformation of dye area in the AFM images. It means that we should include the mechanical and chemical degradation of the optical disks in the life time expectation evaluation.

• 한국염색가공학회지
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• 제11권4호
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• pp.8-15
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• 1999

Electroconductive fiber was obtained by acryl fiber treated with $CuSO_4$. The Properties and structure of fiber and fabric such as mechanical property, electrical conductivity, fine structure, electrification were investigated. The experimental results are as follows 1) The electrical conductivity of the conducting fiber was greatly increased but fine structure and physical properties were similar to acryl fiber 2) Fabric made by mix spinning with conducting fiber was shown great electrification effect. 3) In the mix spinning with conducting fiber, it was necessary to use different. finishing such as milled finish because stiffness of fabric made by mix spinning with conducting fiber was increased and elastic recovery was decreased. 4) The antimicrobial activity of electroconductive fiber blended wool was effective by Cu component for shake flask test.

• Journal of the Korean Physical Society
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• 제73권9호
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• pp.1225-1229
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• 2018

The Drosophila auditory system consists of four large basal segments: the arista, the funiculus, the pedicel, and the scape. When an acoustic stimulus is applied to the arista and the funiculus their mechanical vibrations are transmitted to chordotonal neurons in Johnston's organ where mechanoelectric transduction arises. We study the mechanotransduction mechanism in the Drosophila auditory system by using a laser Doppler vibrometer (LDV) and extracellular electrophysiology. We find that large and small peaks appear alternatively and that the antenna vibration is asymmetric depending on whether the pedicel and the scape are fixed. Interestingly, we find that this asymmetric vibration accompanies the alternating neural peak structure. Here, we propose a mathematical model to explain the alternating peak structure by using a model consisting of two opposing neurons that are modeled as strings. Generally, strings have tension only when they are elongated. This property allows the alternating neural peaks for asymmetric antenna motion.