SEM Tribosystem에 의한 CVD TiN막의 미시적 마모 특성 평가

문봉호(Bongho Moon) 한국표면공학회 2004 한국표면공학회지 Vol.37 No.3

This study surveys the microscopic wear of CYO TiN coatings in repeated sliding, using the SEM Tribosystem as in-situ system. According to the research, the depth of wear groove and the specific wear amount are changed by the transition of the microscopic wear mode. This investigation leads to the fact that the change of wear characteristics produces the transition of the wear mode. In this survey, four modes are observed for CYO TiN coatings with the thickness of 1.6 ㎛: ploughing, powder formation, flake formation and coating delimitation. The microscopic wear properties is quantitatively evaluated in terms with the microscopic wear mode and the specific wear amount. These relationships prove that the observation of wear modes with a SEM Tribosystem is useful to evaluate wear properties.

등산복의 쾌적성 연구

이원자,윤준식 건국대학교 생활문화연구소 2001 생활문화ㆍ예술논집 Vol.24 No.-

This study investigated physiological responses and subjective sensation by dividing the environmental condition into 2 types, climbing wear into 2 Types(HF/CF) and subjects into 2 groups. The indicators of physiological responses included mean skin temperature, sites of skin temperature(Tsk) (head, cheat, far arm, hand, thigh, leg, foot) eardrum temperature, temperature and moisture within the clothing, the amount of sweating, heart rate. The indicators of subjective sensation included thermal sensation, moisture sensation and thermal comfort. They were measured every 5 minutes. The results for this study were follows. First, The higher temperature/moisture (B environment) were the higher this distribution of skin temperature was shown to be in the 'A' environment. It was found that there were significant difference in Te and Tsk, moisture within clothing between the types of climbing wear. In the 'B' environment, it was found that there was not a statistically significant difference. Te and Tsk decreased in HF than LF into the 'A' environment (18±2℃, 40%) significant. The sweating amount of the chest and the back was shown to be highest. Second, It was found that there was not a difference in the thermal sensation between the climbing wear of general materials and the climbing wear of functional materials in both the 'A' environment(18℃, 40%) and the 'B' environment(25℃, 60%). There were environment. But it was found that there were not difference between climbing wears in the 'B' environment(25℃, 60%). Third, It was fecund that the group of general people were Tsk, Tsk, amount of sweating subjects sensation to changes in wear materlals. It was found that were more or less difference between the types of wear materials in each environment.

자동차용 클러치 마찰재의 미끄럼 마모특성에 관한 연구

이한영,김근영,허만대 한국트라이볼로지학회 2004 한국트라이볼로지학회 학술대회 Vol.38 No.-

The wear properties of clutch facing materials with two different amounts of Cu against two different fly wheel materials, gray cast iron and spheroidal graphite cast iron, were studied using the plate on disc test machine. Sliding wear tests were carried out at several sliding speeds and applied loads for several pairs combined with the clutch facing materials and the fly wheel materials. These results showed that the clutch facing material contained the high Cu amount is exhibited in better wear resistance than that contained low Cu amount. And using the gray cast iron as a counter material, clutch facing material has a much lower wear rate. It is obvious that the wear properties of clutch facing material are influenced on the thermal conductivity of clutch facing material and counter material.

써클 콘택트렌즈와 동일 재질 소프트 콘택트렌즈의각막에서의 움직임 비교

김소라,박상희,주선옥,이혜림,박미정 한국안광학회 2012 한국안광학회지 Vol.17 No.1

Purpose: The present study was conducted to compare any difference caused by pigmentation in the centrations and movement patterns on the cornea between circle and soft contact lens with identical material and parameters during lens wearing. Methods: Soft and circle contact lenses with identical material and parameters were applied to twenty eyes with normal tear volume for 3 hrs a day during a total of 5 days and then their lens centrations,the moving distances and rotations by repeat blinking were compared. Results: The lens centration beyond the fitting criteria was shown in initial wears of both soft contact lens and circle contact lens. However, the centration of soft contact lens was changed to the pupil center for being suitable to the fitting criteria with longer wearing time. On the other hand, the decentration of circle contact lens in the horizontal direction was still presented even with longer wearing time. The moving distances of soft contact lens and circle contact lens decreased with the expand of lens wearing but were not significantly different between total wearing period and daily wearing time. The rotation of circle contact lens by repeat blinking was significantly different from that of soft contact lens even when the wearing period was extended. Conclusions: We revealed that the lens centration and movement of circle contact lens on cornea were different from those of regular soft contact lens resulting in bigger difference with the expand of wearing period in the study. 목적: 본 연구에서는 동일 재질 및 렌즈 파라미터를 가진 일반 소프트 콘택트렌즈와 써클 콘택트렌즈의 각막에서중심안정위치와 움직임 양상을 비교하여 착색 여부에 따른 차이를 알아보고자 하였다. 방법: 눈물양이 정상인 20안을 대상으로 동일한 재질 및 파라미터의 일반 소프트 콘택트렌즈와 써클 콘택트렌즈를 각각 1일에 3시간씩 5일 동안 착용시키면서 각막에서의 중심안정위치와 반복적인 순목 후 콘택트렌즈의 이동거리 및 회전량을 측정하고 비교하였다. 결과: 일반 소프트 콘택트렌즈와 써클 콘택트렌즈 모두 착용 초기의 중심안정위치는 피팅 기준에서 벗어나는 경우가 있었으나 일반 소프트 콘택트렌즈의 경우는 착용 시간이 증가함에 따라 동공 중심으로 모이면서 모든 경우에도 피팅 기준에서 벗어나지 않는 적합한 중심안정위치로 변화되었다. 하지만, 써클 콘택트렌즈는 착용 시간이증가하여도 수평 방향으로의 중심이탈이 여전히 존재하였다. 일반 소프트 콘택트렌즈와 써클 콘택트렌즈 모두 반복적인 순목 후 각막에서의 이동거리는 착용기간이 증가할수록 감소하였으나 두 콘택트렌즈 간에는 총 착용 기간이나 일일 착용 시간의 증가에 따른 차이는 통계적으로 유의하지 않았다. 반복적인 순목에 의한 써클 콘택트렌즈의회전양은 착용기간이 증가하였을 때 일반 소프트 콘택트렌즈를 착용한 경우와 비교하여 통계적으로 유의한 차이가있었다. 결론: 써클 콘택트렌즈의 각막에서의 위치 및 움직임은 일반 소프트 콘택트렌즈와 달라지며 이러한 차이는착용기간이 증가하면 더 커짐을 밝혔다.

나노다이아몬드가 첨가된 윤활제의 마모 특성 연구

김승택(Seung Taek Kim),김승목(Seung Mok Kim),박태희(Tae Hee Park),이정석(JungSeok Lee),이영제(YoungZe Lee) 한국트라이볼로지학회 2014 한국윤활학회지(윤활학회지) Vol.30 No.5

Multiple additives can help improve the performance of generally used lubricants. These additives include MoS₂, cadmium, chloride, indium, sulfide, and phosphide, which are harmful to both humans and the environment. Thus, researchers in this industry have been trying to reduce the use of these additives by finding alternatives. Nanodiamonds are one of these candidates. Nanodiamond particles are very hard, chemically stable, and highly heat-conductive. This research involved uniformly dispersing nanodiamond particles in marine engine oils via a matrix synthesis method at various concentrations (0, 0.1, 0.3, 0.5, and 1.0 wt). Friction and wear tests involved constant loads on ball-on-disk specimens, where the ball was AISI 51200 steel, the disk was AISI 1020 steel, and the sliding speed was 0.217 m/s. The lowest wear occurred at a suitable concentration of nanodiamonds (0.3 wt). However, excessive amounts of nanodiamonds caused them to act as abrasive debris because of their hardness, which increased the wear amount. The friction coefficient decreased as the nanodiamond concentration increased because their octagonal, almost spherical shape caused them to act as rolling contact elements between two surfaces.

가스충전소에서 작업복의 정전기 안전관리에 관한 연구

이금환,정재희 한국안전학회 2009 한국안전학회지 Vol.24 No.6

In order to prevent fire and explosion due to the electrostatic discharge at the Gas Station etc. This result will be applied to standard in the future. Wearing the non-electrostatic removing wear, Charged voltage of human body is 3,980V(MIE is approximately 0.79mJ). There is a possibility of fire explosion because the MIE of LP gas is 0.25mJ. In accordance with using period(whasing times), Charged voltage is shown that propensity is increased. Electrostatic charge amount is upper standard(0.6µC) of the hazard of electrostatic removing wear. There is a possibility of fire and explosion. Therefore, countermeasure and management are needed about gas station worker.

유압 모터 하우징 내벽의 마멸 특성 연구

신대영(D. Y. Shin),서동진(D. J. Seo),윤주섭(J. S. Yun),장주섭(J. S. Jang),오주영(J. Y. Oh),최병운(B. Y. Choi) 유공압건설기계학회 2014 유공압건설기계학회 학술대회논문집 Vol.2014 No.9

This study is on problem of jamming gears, which is one of the most degrading factors in hydraulic motor performance. The phenomenon of gear sticking to the inside of a hydraulic motor housing was mathematically modeled as quantitative value of wear, and then structural analysis according to the geometric shape of the motor was performed as an analysis. Also in order to improve the manufacturing quality, a method was proposed to lower the defect rate by statistically analyzing the manufacturing process for parts exposed to wear. The analysis showed that 62.6% of parts hydraulic motor were exposed to wear. For the future, optimization of dimensions, addition of clearance values, and improvement of manufacturing process should be further studies in order to minimize wear and increase the mechanical efficiency.

3차원 인체 형상을 이용한 아웃도어 슬랙스 패턴 비교분석 연구

김희선(Kim Hee-Sun),김경희(Kim Kyung-Hee) 한복문화학회 2014 韓服文化 Vol.17 No.1

The purpose of this study is to design and manufacture experimental clothing based on a comparative analysis of patterns by collecting 3 kinds of patterns in outdoor slacks by brands for women at home targeting middle-aged women, and to suggest a plan for developing improved products through real wearing evaluation, motion optimization evaluation, and virtual wearing evaluation. To compare and analyze the outdoor slacks of the experimental clothing and comparative clothing, 5 subjects were selected based on the waist circumference of middle-aged women with standard body type at age 50~59, and then real wearing evaluation and motion optimization evaluation were carried out. The real wearing evaluation was performed by 10 experts. The virtual wearing evaluation of outdoor slacks of the experimental clothing and the comparative clothing was carried out by generating a virtual model with the I-Virds 3.0 software package. Also, the air gap amount was measured by calculating the air gap area and the air gap distance between clothing and the human body using Auto CAD by Autodesk (USA) based on a real wearing evaluation.

Fatigue Crack Growth and Wear Behaviors in Rheocast Al-Si-Mg Alloys

Kim, Sug-Won,Lee, Ui-Jong,Han, Sang-Won 대한금속재료학회 2003 METALS AND MATERIALS International Vol.9 No.2

Rheocast aluminum alloys, which consist of globular α-Al cells, refined grains and eutectic Si particles, were used to investigate fatigue crack growth and wear characteristics. The Si particles were systematically varied from coarse and acicular shapes to small and globular ones. At low ΔK, fatigue crack growth rates decreased in samples consisting of acicular Si particles of large grain size, which induced a large amount of crack closure. Large and acicular Si particles were easily cracked and separated the particle/matrix interface, which promoted to fracture at smaller ΔK. On the other hand, small Si particles made fatigue crack grow, even at a high ΔK region, and increased the fracture toughness of the alloy. However, in the wear test, small eutectic Si particles were pulled out by friction force during sliding wear and the wear loss amount increased with increase in sliding distance.

Effect of Ti Content on Microstructure and Wear Performance of TZM Alloys Produced by Mechanical Alloying Method

Haktan Sıralı,Doğan Şimşek,Dursun Özyürek 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.10

In this study, changes in microstructure, hardness and wear performance of titanium–zirconium–molybdenum (TZM) alloysproduced by mechanical alloying method with the addition of different amounts of titanium (Ti) were investigated. Mechanicallyalloyed powders were sintered at 1300 °C for 4 h under 10–6 mbar vacuum environment. The produced alloys werecharacterized by scanning electron microscope (SEM + EDS), X-ray diffraction, grain size distribution, hardness and densitymeasurements. In the wear tests, three different loads and five different sliding distances were used. Results showed that theproduced TZM alloys were porous, and the pores in the alloys containing 0.40% and 0.45% Ti were generally located onthe grain boundaries. In alloys containing 0.50% Ti, inside the grain the pore sizes increase, while in the alloy containing0.55% Ti, the pore sizes in grain boundary decrease. Grain size distribution results show that as the Ti content increased, theamount of grain size over 6 μm decreased and smaller than 6 μm increased. Hardness and density results show that whilethe hardness of TZM alloys produced increases depending on Ti content, their density decreases. The highest hardness wasobtained in the TZM alloy containing 0.55% Ti, while the lowest density was obtained in the same alloy. Wear test resultsshow that the lowest weight loss was obtained in TZM alloy containing the highest amount of Ti (0.55%) under all loads.