• 복식문화연구
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• 제16권3호
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• pp.518-532
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• 2008

The purposes of this study were to investigate the relationships between women's self-image and the preference and the wearing frequency of knit-wears, and to examine the characteristics of the design elements that influence the preferred knit-wear images. The subjects were 277 female college students and working women living in metropolitan area of Seoul. The data were analyzed by using descriptive analysis, factor analysis, Cronbach's $\alpha$-reliability coefficient, Pearson's correlation coefficient, and multiple regression analysis. Four dimensions of women's self-images were derived by factor analysis; elegance, conservativeness, individuality, and maturity. Women with conservative self-image preferred simple knit-wears and women with high rate for individuality preferred splendid and sporty knit-wears. Women with elegant self-image disliked sporty knit-wears. Women with conservative self-image preferred white, and those who rated their self-image to be individuality preferred various colors including yellow, blue, green, purple, pink, and sky-blue. Women with mature self-image preferred black and beige. Women with individuality as their self-image preferred jacquard pattern and abstract pattern. There was a higher wearing frequency for all four seasons for women with conservative self-image, and there was higher wearing frequency in the winter for those with elegant self-images. Women who preferred simple knit-wears showed preference for single color with no prints and low chroma color, and those who preferred sporty knit-wears showed preference for elastic materials. Women who preferred neat and elegant knit-wears showed preference for argyle check pattern.

• 대한소아치과학회지
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• 제34권2호
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• pp.273-284
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• 2007

본 연구는 광중합형 복합레진 Composan LCM Flow(Promedica, Germany), Clearfil ST(Kuraray medical, Japan) Durafil VS(Heraeus Kulzer, U.S.A), Point 4(Kerr, U.S.A)를 사용하여 각 제품의 물리적, 화학적 평가를 하고자 하였다. 마모시험 후 마모된 면의 깊이를 측정하였고 0.1N NaOH에 보관 후. 각 제품의 분해저항성을 무게손실, 표면하 분해층 깊이, 용출된 Si 농도를 기준으로 평가하였으며 주사전자현미경과 공촛점 레이저 현미경으로 분해 층을 관찰하여 다음과 같은 결과를 얻었다. 1. 무게 손실량은 $1.02{\sim}6.04%$까지 다양하였으며 Durafil VS에서 가장 높았다$(6.04{\pm}0.29%)$. 2. 분해층 깊이는 Durafil VS이 가장 깊었고 Clearfil ST, Point 4, Composan LCM Flow순이었고 Point 4와 Composan LCM Flow는 다른 제품과 유의한 차이를 보였다(p<0.001). 3. Si 용출량은 Clearfil ST가 가장 많았으며 Durafil VS, Composan LCM Flow, Point 4 사이에 유의한 차이를 보였다(p<0.001). 4. 주사전자현미경 관찰시 표면 양상 및 분해층 깊이를 관찰할 수 있었고 공촛점 레이저 현미경 관찰시 NaOH 용액에 보관한 후 수복재의 기질과 충전제 사이의 결합의 파괴 양상을 관찰할 수 있었다. 5. 최대마모깊이는 Durafil VS, Composan LCM Flow, Point 4, Clearfil ST 순으로 낮았으며 유의한 차이를 보이지 않았다(p>0.001). 6. 각 제품의 Si 용출량과 분해층 깊이 사이(r=0.892, p<0.01), Si 용출량과 무게손실 사이(r=0.736, p<0.01)에는 유의한 상관관계를 보였다.

• Journal of Korean Vacuum Science & Technology
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• 제6권2호
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• pp.105-107
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• 2002

a-C:H films were coated on windows of mobile telephone by RF plasma chemical vapor deposition equipment made in our company. Thickness of the coatings is about 0.7 micrometers and they have high hardness, low friction coefficient, good adhesion, high optical transparency and chemical inertness. Knoop hardness of the diamond-like carbon films on glass substrate is 2328 kg/mm$^2$. The adherence between films and substrate is good and shows to be 69 N by scratching test. The optical performance is improved obviously owing to coat the film on it. The index of the coated windows is 2.5, transmission of visible light is larger than 90%, and transmission of ultraviolet light decreases by 30% and the ultraviolet light can be obstructed obviously. The coated glass also has self-clean effect and decontamination ability. The films have hydrophobic character and the soakage angle of water drop is larger than 90 degrees. The windows have fog-proof ability owing to eliminate the capillary phenomena in the inner surface. The physics and chemical properties of the coated windows are steady. Study indicates that the performance of a-C:H coated mobile phone windows are improved notably on wear-resistance, corrosion-proof and optical properties and it is excellent mobile windows protective coatings.

• 한국표면공학회지
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• 제41권5호
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• pp.245-253
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• 2008

The porous metal material is used for injection metal mold with a great deal of gas production because it makes plenty of gas exhausted through pores formed in the metal mold. A canning HIP method was conventionally used for manufacturing of porous metals, but because of difficulty of process control and high cost of production its application was limited. In this experiment, porous metal mold material was produced by an enhanced vacuum sintering method with simply controlled and economical process and porosities/mechanical properties with variation of sintering temperature and duration time during vacuum sintering were studied. As a result, quality goods were obtained at optimized conditions as follows: sintering temperature of $1230^{\circ}C$, duration time of 2 hr and showed superior properties in wear loss and thermal conductivity and the same properties in hardness, TRS (Transverse Rupture Strength), and thermal expansion coefficient in comparison with those under canning HIP.

• Tribology and Lubricants
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• 제23권6호
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• pp.298-300
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• 2007

Frictional characteristics of mesoporous $SiO_2$ thin films were evaluated with different pore sizes. The films were manufactured by sol-gel and self-assembly methods to have a porous structure. The pores on the surface may play as the outlet of wear particle and the storage of lubricant so that the surface interactions could be improved. The pores were exposed on the surface by chemical mechanical polishing (CMP) or plasma-etching after forming the porous films. The ball-on-disk tests with mesoporous $SiO_2$ thin films on glass specimen were conducted at sliding speed of 15 rpm and a load of 0.26 N. The results show considerable dependency of friction on pore size of mesoporous $SiO_2$ thin films. The friction coefficient decreased as increasing the pore size. CMP process was very useful to expose the pores on the surface.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2000년도 제31회 춘계학술대회
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• pp.180-186
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• 2000

Friction materials with four different sizes of zircon - l${\mu}{\textrm}{m}$, 6${\mu}{\textrm}{m}$, 75${\mu}{\textrm}{m}$, 140${\mu}{\textrm}{m}$- were investigated to evaluate the size effects of abrasive particles used in the automotive brake pads on brake performance. Although the brake pads with the largest size of zircon showed a good frictional stability and low wear, rotors were severely abraded due to the aggressiveness of coarse Bircon. As the siBe of zircon decreased. friction force and the amplitude of friction coefficient increased. Considering the above results, abrasive materials were thought to destroy transfer film and the extent of the destruction depends on the size of zircon. The small size zircon was not effective in developing a transfer layer on the rotor surface while minimizing the damage on the counter surface.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.51-52
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• 2002

We report results on microtribological studies of chemically grafted nanoscale polymer layers of different architecture with thickness below 30 nm. We have fabricated the molecular lubrication coatings from elastomeric tri-block copolymers and tested two different designs of corresponding nanocomposite coatings. We observed a significant reduction of friction forces and an increase of the wear stability when a minute amount of oil was trapped within the grafted polymer layer. These polymer gel layers exhibited a very steady friction response and a small value of the coefficient of friction as compared to the initial polymer coating. A polymer 'triplex' coating has been formed by a multiple grafting technique. The unique design of this layer Includes a hard-soft-hard architecture with a compliant rubber interlayer mediating localized stresses transferred through the topmost hard layer. This architecture provides a non-linear mechanical response under a normal compression stress and allows additional dissipation of mechanical energy via the elastic rubber interlayer.

• 대한기계학회논문집A
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• 제21권1호
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• pp.83-92
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• 1997

In a study on the development of Cu-based sintered friction materials, the specimens pressed with various compacting pressures $(3-6 ton/cm^2/)$ have been evaluated to find the optimum condition of compacting pressure. As compacting pressure increased up to $(5 ton/cm^2/)$, mechanical properties such as density, hardness, bending strength, wear and coefficient of friction, etc. improved remarkably, but up to 6 ton/cm$^{2}$, decreased slightly because of traps of gases and water vapors in specimen. Disk assembly composed of 12 pieces of Cu-based friction materials has been compared with one of asbestos-and nonasbestos-based friction materials. In dynamic and driving tests to find burst spin strength, corrosion area rate and friction properties, etc., Cu-based sintered friction materials showed better properties than the others, especially in severe conditions because oxides such as $Cu_2O; and; SnO_2$ in the friction surface of friction materials were formed.

• 한국결정성장학회지
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• 제13권1호
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• pp.36-40
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• 2003

$CH_4/(C_2H_5O)_4Si/H_2$/Ar가스 혼합물을 출발 반응원료로 하여 플라즈마 화학기상증착법으로 Si 기판 위에 유사 다이아몬드 나노복합체(diamond-like nanocomposite, DLN) 박막을 증착하였다. 성장된 막의 화학구조와 미세구조를 확인하였으며 막의 마모특성을 평가하였다. 증착된 DLN 막은 다이아몬드와 유사한 a-C:H 구조와 실리카와 유사한 a-Si:O 구조가 네트워크 형태로 구성되어 있음을 확인하였으며 극도로 낮은 마모계수와 마모속도를 나타내어 내마모 코팅용 보호막으로 의 응용에 적합한 것으로 나타났다.

• Advances in concrete construction
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• 제6권4호
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• pp.363-373
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• 2018

Portland cement pervious concrete (PCPC) is an effective pavement material to solve or reduce the urban waterlogging problems. The Mechanical properties, the permeability, the abrasion resistance and the frost resistance of PCPC without fine aggregate were investigated. The increase of porosity was achieved by fixing the dosage of coarse aggregate and reducing the amount of cement paste. The results show that the compressive strength and the flexural strength of PCPC decrease with the increase of porosity. The permeability coefficient and the wear loss of PCPC increase with the increase of the porosity. The compressive strength and the flexural strength of PCPC subjected to 25 freeze-thaw cycles are reduced by 13.7%-17.8% and 10.6%-18.3%, respectively. For PCPC subjected to the same freeze-thaw cycles, the mass loss firstly increases and then decreases with the increase of the porosity. The relative dynamic modulus elasticity decreases with the increase of freeze-thaw cycles. And the lower the PCPC porosity is, the more obvious the dynamic modulus elasticity decreases.