• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2004년도 학술대회지
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• pp.139-142
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• 2004

The object of the present work is the acoustic emission energy analysis of subambient pressure tri-pad slider. Head/disk interaction during start/stop and constant speed were detected by using acoustic emission (AE) test system The frequency spectrum analysis is performed using the AE signal obtained during the head/disk interaction Natural frequency analysis was performed using Ansys program. Acoustic emission energy was calculated for the slider modes.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.924-929
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• 2001

The flying height of contact slider is determined by vertical and pitching motions of slider. This paper performed the computer simulation for flying height change of contact slider. It is changed by many parameters, contact stiffness, contact damping, air bearing stiffness ratio, a location of mass center, and so on. Computer simulation is performed for knowing for what change of these parameters influences in flying height of contact slider. Disk surface is modeled in harmonic wave with from 10㎑ to 600㎑. Tri-pad slider is modeled in that contact slider has 2-DOF motion (vertical motion, pitching motion). Tri-pad contact slider is analyzed by numerical analysis method in computer simulation.

• KSTLE International Journal
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• 제5권1호
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• pp.28-31
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• 2004

The object of the present work is the natural frequency analysis of subambient pressure tri-pad and pico sliders. Head/disk interaction during start/stop and constant speed were detected by using the acoustic emission (AE) test system. The frequency spectrum analysis is performed using the AE signal obtained during the head/disk interaction. The FFT (Fast Fourier Transform) analysis of the AE signals is used to understand the interaction between the AE signal and the state of contact. Natural frequency analysis was performed using the Ansys program. The results indicate acceptable accordance of finite element calculation results with the experimental results.

• Journal of the Korean Wood Science and Technology
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• 제42권6호
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• pp.740-746
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• 2014

꾸지뽕나무 미숙과를 50% 발효주정으로 추출하고, 농축한 추출용액을 n-hexane, chloroform, ethyl acetate, butanol로 순차적으로 분액하여 수용성 조추출물을 얻었다. 수용성 조추출물을 분취용 겔 투과 크로마토그래피(Gel Permeation Chromatography, GPC)를 실시하여 다당류(F1)를 분리하였다. F1을 가수분해하여 단당 성분 분석을 실시한 결과 glucose, galactose, arabinose, xylose 등 4가지로 구성되어 있었으며, 그 조성비는 6.1 : 1.8 : 3.1 : 1.0이었다. F1에 acetyl 기의 치환여부와 uronic acid의 존재 유무를 확인하기 위해 FT-IR로 측정하고 염산 가수분해 한 다음 HPLC 분석을 실시한 결과, 두 가지 모두 없는 것으로 분석되었다. 결합 위치 확인을 위해 permethylation, 산 가수분해, 환원, silylation을 순차적으로 실시하여 얻은 partially methylated alditol silylate (PMAS)들을 GC-MS 분석을 실시한 결과, 1,5-di-O-trimethylsilyl-2,3,4-tri-O-methyl xylose, 1,5-di-O-trimethylsily-2,3,4-tri-O-methyl arabinose, 1,4,5-tri-O-trimethylsily-2,3-di-O-methy arabinose, 1,3,5-tri-O-trimethylsily-2,4,6-tri-O-methyl glucose, 1,4,5-tri-O-trimethylsily-2,3,6-tri-O-methyl galactose, 1,4,5-tri-O-trimethylsily-2,3,6-tri-O-methyl glucose, 1,3,5,6-tetra-O-trimethylsily-2,4-di-O-methyl galactose, 1,3,5,6-tetra-O-trimethylsily-2,4-di-O-methyl glucose로 구성되어 있었고 그 조성비는 1.1 : 1.0 : 4.9 : 7.5 : 3.0 : 3.1 : 1.4 : 1.5였다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2003년도 학술대회지
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• pp.384-387
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• 2003

The object of the present work is the analysis of head/disk interaction during start/stop and constant speed operation using acoustic emission (AE). The frequency spectrum analysis is performed using the AE signal obtained during the head/disk interaction. The FFT (Fast Fourier Transform) analysis of the AE signals is used to understand the interaction between the AE signal and the state of contact.

• Weed & Turfgrass Science
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• 제2권4호
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• pp.395-401
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• 2013

본 연구는 켄터키블루그래스 내에 발생한 크리핑벤트그래스를 방제하기 위하여 제초제를 선발하고, 그 피해 지역에 켄터키블루그래스의 샌드인젝션파종에 의한 회복방법을 개발하기 위해 수행되었다. 약제선발시험에 이용된 제초제는 메코프로프액제(mecoprop; MCPP), 트리클로로 피르티이에이액제(triclopyr-TEA; Tri-T), 이마자퀸액제(imazaquin; Ima), 벤타존액제(bentazone; Ben) 및 페녹슐람 피라조설퓨론에틸입상수화제(penoxsulam pyrazosulfuronethyl; PPE)와 같은 선택성제초제와 글리포세이트액제(glyphosate; Gly), 파라콰트디클로라이드액제(paraquat dichloride; Pad) 및 글리포세이트암모늄 옥시플루오르펜입 상수화제(glyphosate ammonium oxyflorfen; GAO)와 같은 비선택성제초제를 이용하였다. 엽색지수와 엽록소지수 및 방제 효과를 통해 크리핑벤트그래스의 방제에 효과적인 선택성제초제는 Tri-T 배량(2Tri-T)처리이었으며, 비선택성 제초제 중에서는 GAO 1/5량(1/5GAO)이 우수하였다. 크리핑벤트그래스가 침입한 켄터키블루그래스 포장에서 2Tri-T와 1/5GAO의 방제효과는 각각 6.0과 7.4로 우수하였다. 방제지역에 켄터키블루그래스를 샌드인젝션을 통해 파종 후 약 30일 후에는 약 $70{\pm}3%$ 정도의 피복율을 보였고, 50일 후에는 대조구와 비슷하게 회복되었다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2000년도 제31회 춘계학술대회
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• pp.24-33
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• 2000

The effect of particulate contamination on friction and wear between a negative-pressure picoslider / tri-pad nanoslider and laser-textured disk was studied. Particles of different concentration were injected at the head-disk interface consisting of disks with various textures and slider types at different speed. Durability increased and coefficient of friction decreased as the disk speed increased in a contaminated environment. Frictional characteristics and durability in the data zone were better for those of the laser-textured zone. It was also found that durability of head-disk interface (HDI)decreased as the particle concentration increased. The interface durability with a picoslider was better than that with a nanoslider at any condition in a contaminated environment. Based on the test results, mechanisms were proposed to explain the reasons why durability with a picoslider was superior to that with a nanoslider.

• Tribology and Lubricants
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• 제16권6호
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• pp.469-476
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• 2000

The effect of particulate contamination on the friction and wear between a negative-pressure picoslider/tri-pad nanoslider and laser-textured disk was studied. Particles of different concentration were injected at the head-disk interface consisting of disks with various textures and slider types at different speed. Durability increased and coefficient of friction decreased as the disk speed increased in a contaminated environment. Frictional characteristics and durability in the data Bone were better than those in the laser-textured zone. It was also found that durability of head-disk interface (HDI) decreased as the particle concentration increased. The interface durability with a picoslider was better than that with a nanoslider at any condition in a contaminated environment. Based on the test results, mechanisms were proposed to explain the reasons why durability with a picoslider was superior to that with a nanoslider.

• 사상체질의학회지
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• 제28권2호
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• pp.132-146
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• 2016

Objectives This study's object was to observe the comparative effects of Yangkyuksanhwa-tang, Palmulgunja-tang and Cheongpyesagan-tang on the chronic LT4(levothyroxine) induced hyperthyroidism in rats.Methods Six groups, each of 8 rats in group, were used in this study. Saline and distilled water treated rats are intact control group. Hyperthyroidism was induced by daily subcutaneous LT4 300 μg/kg treatment for 27 days(LT4 control). Since 12th LT4 treatment PTU(propylthiouracil) 10 mg/kg was intraperitoneal injected(PTU group) and aqueous extracts of Yangkyuksanhwa-tang, Palmulgunja-tang and Cheongpyesagan-tang(YS, PG and CS) 500 mg/kg were orally administrated(YS, PG, CS group), once a day for 15 days. The differences in the body, thyroid gland and epididymal fat pad weights, serum T3(tri-iodothyronine), T4(thyroxine), TSH(thyroid-stimulating hormone), thyroid gland and epididymal fat pad histopathology, liver weight, AST(asparte aminotransferase), ALT(alanine aminotransferase) concentrations, hepatic lipid peroxidation, GSH(glutathione), SOD(superoxide dismutase), CAT(catalase) activities, liver histopathology were observed to evaluate effects on hyperthyroidism, liver damages and antioxidant effects.Results As results of LT4 treatment, hyperthyroidism and related liver damages such as lower body, thyroid weights, higher serum T3, T4, AST, ALT levels, thinner follicular lining epithelium in thyroid glands were observed. However, these symptoms were inhibited by oral treatment of YS, PG and CS. As compared with PTU treatment, these herbal prescriptions showed lower overall efficacy on the hyperthyroidism, but YS showed more favorable effects on the hepatic antioxidant defense systems.Conclusions This results suggest that YS, PG and CS favorably control the LT4 induced hyperthyroidism and related liver damages in rats through modulation of the hepatic antioxidative defense systems.

• Tribology and Lubricants
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• 제36권1호
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• pp.39-46
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• 2020

Air stages are usually applied to precision engineering in sectors such as the semiconductor industry owing to their excellent performance and extremely low friction. Since the productivity of a semiconductor depends on the acceleration and deceleration performance of the air stage, many attempts have been made to improve the speed of the stage. Even during sudden start or stop sequences, the stage should maintain an air film to avoid direct contact between pad and the rail. The purpose of this study is to quantitatively predict the dynamic behavior of the air stage when acceleration and deceleration occur. The air stage is composed of two parts; the stage and the guide-way. The stage transports objects to the guideway, which is supported by an externally pressurized gas bearing. In this study, we use COMSOL Multiphysics to calculate the pressure of the air film between the stage and the guide-way and solve the two-degree-of-freedom equations of motion of the stage. Based on the specified velocity conditions such as the acceleration time and the maximum velocity of stage, we calculate the eccentricity and tilting angle of the stage. The result shows that the stiffness and damping of the gas bearing have non-linear characteristics. Hence, we should consider the operating conditions in the design process of an air stage system because the dynamic behavior of the stage becomes unstable depending on the maximum velocity and the acceleration time.