• 제목/요약/키워드: rubber surface

검색결과 699건 처리시간 0.031초

자기조립법에 의한 $\alpha$-D-만노실 풀러렌[$C_{60}$]-금 나노입자 필름 제조 (Preparation of Self-Assembled of $\alpha$-D-Mannosyl Fullerene[$C_{60}$]-Gold Nanoparticle Films)

  • 윤신숙;황성호;고원배
    • Elastomers and Composites
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    • 제43권4호
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    • pp.264-270
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    • 2008
  • 3-아미노프로필메톡시 실란을 처리한 반응성 있는 유리표면 위에 "LbL" 방법을 사용하여 $\alpha$-D-만노실 풀러렌[$C_{60}$]-금 나노입자를 자기조립 하였다. 표면 처리한 유리막을 $\alpha$-D-만노실 풀러렌[$C_{60}$]과 헥산 티올레이트/아미노 티오페녹사이드-금나노입자를 포함하고 있는 용액속에 교대로 담그었다. $\alpha$-D-만노실 풀러렌[$C_{60}$] -금 나노입자 필름을 시간에 따라 다중성(5층)막으로 제조하였다. 자외선-가시광선 분광기를 사용한 자기조립 나노입자 필름의 분석은 530 nm 일 때 금 나노입자의 표면 플라스몬 밴드로 인해 다중성(5층)막이 형성되는 것을 보여주었다.

통신장비용 앰플리파이어 액체냉각장치 및 냉각유체 분배기의 최적설계 및 성능특성 (Optimum Design of Liquid Cooling Heat Exchangers and Cooling-Fluid Distributors for a Amplifier Cabinet of Telecommunication Equipment)

  • 윤린;김용찬;김현종;최종민;천덕우
    • 설비공학논문집
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    • 제18권1호
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    • pp.24-30
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    • 2006
  • Three liquid cooling heat exchangers for cooling of telecommunication equipment were designed and their cooling performances were tested. The liquid cooling heat exchangers had twelve rectangular channels $(5\times3 mm)$ with different flow paths of 1, 4, and 12. Silicon rubber heaters were used to provide heat flux to the test section. Heat input was varied from 75 to 400 W, while flow rate and inlet temperature of working fluid were altered from 1.2 to 4.0 liter/fin and from 15 to 3$30^{\circ}C$, respectively. The 4-path heat exchanger showed lower and more uniform average inner temperatures between heaters and the surface of heat exchanger than those of the others. To obtain optimal distribution of working fluid to each channels of liquid cooling heat exchangers, 2-3-2 and 4-3 type tube distributors were designed, and their distribution performances of working fluid were numerically and experimentally investigated. The distributor of the 2-3-2 type showed superior distribution performance compared with those of the 4-3 type distributor.

자기장에 따른 자기유변탄성체의 스틱 슬립 현상 연구 (Stick-slip Characteristics of Magnetorheological Elastomer under Magnetic Fields)

  • 연성룡;이광희;김철현;이철희;최종명
    • Tribology and Lubricants
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    • 제31권1호
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    • pp.6-12
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    • 2015
  • This paper investigates the stick-slip characteristic of magnetorheological elastomer (MRE) between an aluminum plate and the surface of the MRE. MRE is a smart material and it can change its mechanical behavior with the interior iron particles under the influence of an applied magnetic field. Stick-slip is a movement of two surfaces relative to each other that proceeds as a series of jerks caused by alternate sticking from friction and sliding when the friction is overcome by an applied force. This special tribology phenomenon can lead to unnecessary wear, vibration, noise, and reduced service life of work piece. The stick-slip phenomenon is avoided as far as possible in the field of mechanical engineering. As this phenomenon is a function of material property, applied load, and velocity, it can be controlled using the characteristics of MRE. MRE as a soft smart material, whose mechanical properties such as modulus and stiffness can be changed via the strength of an external magnetic field, has been widely studied as a prospective replacement for general rubber in the mechanical domain. In this study, friction force is measured under different loads, speed, and magnetic field strength. From the test results, it is confirmed that the stick-slip phenomenon can be minimized under optimum conditions and can be applied in various mechanical components.

기선권현 강의 연구-III (Study on the Anchovy Boat Seine-III Experimental Operation of the Improved Gear Model 79)

  • 이병기
    • 수산해양기술연구
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    • 제15권2호
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    • pp.83-94
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    • 1979
  • 權現網漁具의 網形에 관하여는 李등이 1971년에 在來式에 관하여, 1978년에 日本式 파치網에 관하여 模型實驗을 실시하여 보고한 바 있으나, 이번에 이들 漁具의 場点을 살리면서 短點을 보안한 試驗漁具改式良 79型을 재작하여, 1979년 5월부터 10월까지 6개월간. 멸치漁場이 형성되는 廈南一圓에서 試驗操業을 실시하여 그 漁具의 性能을 검토하고, 漁獲性能을 비교한 바, 그 性能이 在來式보다 우수하다는 것이 규명되었다

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GTR 및 미발포 Expancel이 경질우레탄폼의 열전도특성에 미치는 영향 (Effects of GTR and Unexpanded Expancel Powders on Thermal Conducting Characteristics of Rigid Polyurethane Foams)

  • 안원술
    • 한국산학기술학회논문지
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    • 제13권6호
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    • pp.2846-2851
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    • 2012
  • 미세하게 분쇄된 폐타이어 분말(GTR)과 미발포 $Expancel^{(R)}$ 분말이 경질 폴리우레탄 발포체(PUF)의 열전도 특성에 미치는 영향을 연구하였다. 마이크론 크기로 분쇄된 GTR과 $100^{\circ}C$ 이상의 온도 영역에서 약 40배 부피로 팽창 가능한 $Expancel^{(R)}$ 미세분말을 사용하였고 이들이 경질 PUF 생성 시의 발포 기핵제 역할에 의한 기포크기 감소효과 및 이로 인한 PUF의 열전도특성 개선 효과를 집중적으로 살펴보았다. 연구의 결과로서, GTR이 충전된 PUF 샘플들의 열전도도는 GTR 함량이 증가함에 따라 선형적으로 증가하는 현상을 나타내는 반면, $Expancel^{(R)}$이 도입된 샘플들은 농도에 따라 약간 감소하는 특성을 보여 주었다. 이러한 결과로부터 GTR은 PUF 생성에서 증량제의 역할이 상대적으로 우세하여 단열 특성에 기여하지 못하는 반면, $Expancel^{(R)}$은 분말의 표면극성으로 인한 발포 기핵 작용에 의하여 셀 크기를 감소시킴으로서 단열효과에 기여할 수 있는 것으로 생각되었다.

칼라 아스팔트 포장의 색채 표면보수를 위한 칼라코팅 공법 성능평가 (Evaluation of Color Coating Method for Color Maintenance of Color Asphalt Pavement)

  • 박태순
    • 한국도로학회논문집
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    • 제13권4호
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    • pp.93-101
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    • 2011
  • 본 연구는 칼라아스팔트 포장의 표면 색채를 보수하기 위하여 사용되는 칼라코팅 공법에 대한 평가를 버스전용 차선에서 실시한 실내외 시험에 관한 연구이다. 교통과 시간의 경과에 따라 칼라아스팔트 표면은 탈변색, 마모가 발생하여 표면 색상에 손상이 발생하게 된다. 총 9개 공법에 대하여 평가를 실시하였다. 실내시험 항목으로 UV시험, 부착성능 및 타버시험장치를 사용하여 내마모시험을 실시하고 현장시험으로는 BPT를 이용한 미끄럼저항시험과 현장 육안조사를 실시하였다. 실험 결과 각 공법들은 서로 다른 공학적 특징을 보였는데 이러한 결과는 각 공법에 사용한 주재료와 관련이 있는 것으로 판단하였다. 고무에폭시를 주재료로 사용한 공법이 평가된 공법 중에서 만족할만한 결과를 보였으나 100일 후 현장 추적조사 결과 모든 공법이 탈변색, 마모, 벗겨짐 현상이 심하게 발생하여 코팅공법으로 적합하지 않으며 추후 적용하기 위해서는 연구가 필요한 것으로 나타났다.

고등학교 급식시설 운영실태 및 ATP Bioluminescence를 이용한 위생상태 조사연구 (Evauation of Management & Hygienic Status of High School Foodservice using ATP Bioluminescence Assay)

  • 계승희;황성희
    • 한국식품영양학회지
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    • 제30권3호
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    • pp.515-524
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    • 2017
  • An investigation was conducted to evaluate the hygienic status of 53 high school foodservice systems in Gyeonggi province by using hygiene management guide checklist, ATP bioluminescence assay of food utensils were conducted during process. The 5 hygiene management guide checklist groups about personal hygiene, cooking facilities control, cross contamination control, cook and storage control, management control were checked by experts and had good grades but there were some inadequate behaviors on observation. Total cleaning levels were inadequate, including hand, rubber gloves, aprons, knives, food tray, machine and instruments. The possibility of cross contamination is also noted in handles for refrigerators, ovens, food dryers, hand washing. It was also noted that there were too much work on the nutritionist and cook, additional personnel need to be added. lack of space, deterioration of facilities were identified in some high school foodservice systems. ATP bioluminescence assay was conducted on surface of food facilities, ATP ranged $1,393{\pm}5,041.2RLU$ on yellow gloves, $244{\pm}258.7RLU$ on pink gloves, $3,780{\pm}11,418.6RLU$ on apron, $49,056{\pm}62,831.4RLU$ on refrigerator grip, $41,422{\pm}61,259.8RLU$ in oven, $31,407{\pm}41,344.9RLU$ on hand cleaning board.

Development of a Practical Two-Microphone Impedance Tube Method for Sound Transmission Loss Measurement of Sound Isolation Materials

  • Ro, Sing-Nam;Hwang, Yoon;Lee, Dong-Hoon
    • International Journal of Air-Conditioning and Refrigeration
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    • 제11권3호
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    • pp.105-113
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    • 2003
  • This study developed a practical two-microphone impedance tube method to measure the sound transmission loss of sound isolation materials without the use of an expensive reverberation room or an acoustic intensity probe. In order to evaluate the validation and applicability of the two-microphone impedance tube method, sound transmission losses for several sound isolation materials with different surface density and bending stiffness were measured, and the measured values were compared with the results from the reverberation room method and the theory. From the experimental results, it was found that the accuracy of sound transmission loss obtained by the impedance tube method depends upon the diameter size of the impedance tube (i.e., tested sample size). For sound isolation materials having relatively large bending stiffness such as acryl, wood, and aluminum plates, it was found that the impedance tube method proposed by this study was not valid to measure the sound transmission loss. On the other hand, for sound isolation materials having relatively small bending stiffness such as rubber, polyvinyl, and asphalt sheets, the comparisons of transmission loss between the results from the impedance tube method and the theory showed a good agreement within the range of the frequencies satisfying the normal incidence mass law. Therefore, the two-microphone impedance tube method proposed by this study can be an effective measurement method to evaluate the sound transmission loss for soft sound isolation sheets having relatively small bending stiffness.

산업용 단선 궤도 차량의 주행 동특성에 관한 연구 (A Study on Dynamic Characteristic Analysis for the Industrial Monorail Vehicle)

  • 이수호;정일호;이형;박중경;박태원
    • 대한기계학회논문집A
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    • 제29권7호
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    • pp.1005-1012
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    • 2005
  • An OHT(Over Head Transportation) vehicle is an example of the industrial monorail vehicle, and it is used in the automobile, semiconductor, LCD manufacturing industries. OHT vehicle is moved by main wheels and guide rollers. The major function of the main wheel is to support and drive the OHT vehicle. The roles of the guide roller is the inhibition of derailment and steering of the OHT vehicle. Since the required vehicle velocity becomes faster and the required load capacity is increased, the durability characteristics of the wheel and roller, which was made of urethane, need to be increased. So it is necessary to estimate the fatigue life cycle of the wheel and roller. In this study, OHT dynamic model was developed by using the multi body dynamic analysis program ADAMS. Wheel and roller are modeled by the 3-D surface contact module. Especially, motor cycle tire mechanics is used in the wheel contact model. The OHT dynamic model can analyze the dynamic characteristic of the OHT vehicle with various driving conditions. And the result was verified by a vehicle traveling test. As a result of this study, the developed model is expected to predict wheel dynamic load time history and makes a contribution to design of a new monorail vehicle.

코팅재료를 이용한 비쇄석골재의 성능향상 (Improvement of Low-quality Local Aggregates Using Coating Materials)

  • 박대욱;김민구
    • 한국도로학회논문집
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    • 제8권3호
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    • pp.39-48
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    • 2006
  • 세립의 포리에틸렌, 카펫부산물, 시멘트와 라텍스로 코팅된 매끄럽고 둥근 규사질의 강자갈을 가지고 실험적인 조사가 이루어졌으며 아스팔트 혼합물 공시체를 만들었다. No. 4번체 이상에 남아 있는 골재만 코팅을 하였다. 개념은 매끄럽고 둥근 강자갈을 코팅함으로서 표면 거칠기를 증가시켜 공학적 특성이 우수한 혼합물을 만들어 내는 것이다. 표준 테스트와 비표준 테스트를 이용하여 아스팔트 혼합물 공시체를 평가하였다. 코팅과정과 제한된 혼합물 공시체 테스트 결과에 근거하여 다음과 같은 결과를 얻을 수 있었다. 세 가지 종류로 코팅된 골재를 사용한 혼합물들은 Hveem과 Marshall 안정도, 인장강도와 회복탄성계수가 증가되었으며 이는 코팅되지 않은 골재로 만든 혼합물과 비교하여 소성변형과 균열저항성이 향상된 것으로 판단할 수 있다.

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