• 제목/요약/키워드: contact angle test

검색결과 351건 처리시간 0.032초

표면거칠기와 액막 증발에 관한 상관 관계 고찰 (Investgation on the Relationships between the Surface Roughness and Film Evaporation)

  • 김균석;김익생;유병훈;김도형;김춘동;최고원
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 춘계학술대회논문집D
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    • pp.272-279
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    • 2001
  • The objective of this paper is the investigation of the relationships between the surface roughness and film evaporative characteristics of the surface. For example, when the droplet of liquid is in contact with the solid surface, its behavior strongly depends on the surface characteristics. The material properties and geometry - profile shape, waviness, roughness - of the surfaces have strongly influenced on the wettability of the droplet. To investigate the effect of the surface roughness on the film evaporation, firstly, the characteristics of wettabilities were studied according to contact angle and surface tree energy of specimens with various roughness heights. Secondly, the experimental test were carried out on capacities of the tubes diversly roughened by using different kinds of emery papers. Finally, the relationships between the film evaporation characteristics and surface roughness were explained by means of the correlation of contact angle and surface free energy with surface roughness and the influences of surface tree energy on the heat transfer performance.

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사용후 연료 건식저장용기 1/8규모 축소모형 지진회전응답해석 (Seismic Rocking Response Analysis of 1/8 Scale Model for a Spent Fuel Storage Cask)

  • 이재한;서기석;구경회;조천형;최병일;이흥영;염성호
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 2005년도 춘계 학술발표회 논문집
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    • pp.383-389
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    • 2005
  • This research is to develop a seismic response analysis method for a spent fuel storage cask. FEM model is built for the test model of 1/8 scale spent fuel dry storage cask using available 3D contact conditions in ABAQUS/Explicit. Input load for this analysis os a seismic wave of El-centro earthquake, and the friction and damping coefficients in the analysis condition we obtained from the test result. Penalty and kinematic contact methods of ABAQUS are used for mechanical contact formulation. The analysis method was verified for rocking angle obtained by seismic response tests. The kinematic contact method with an adequate normal contact stiffness showed a good agreement with tests.

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Wetting Balance Test를 이용한 솔더의 젖음성 분석 (Wettability Analysis of Solders using Wetting Balance Test)

  • 정도현;임동욱;백범규;임송희;윤종혁;정재필
    • 마이크로전자및패키징학회지
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    • 제24권2호
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    • pp.1-9
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    • 2017
  • Recently, there has been a continuous researches on solders having sophisticated and improved performance due to demand for high-density and miniaturization of electronics, and development of solder for automotive electronics which can be used in harsh environment. When developing a new solder alloy, there is a wettability of solder on substrate for things to consider, and the wetting balance test is one of the methods for measuring that one. In this paper, the wetting balance test is introduced, and the calculus of the surface tension of solder and the contact angle between solder and substrate using wetting curve obtained is introduced too. In detail, the principle and test method of the wetting balance test, the introduction of the parameters with important meaning in the wetting curve, the method of calculating the contact angle as well as the surface tension of the solder using the shape of the solder meniscus.

정상인의 평지보행과 트레드밀 보행 시 족저압의 특성 비교 (The Comparison of Characteristics of Foot pressure between Treadmill and Ground walking in Normal person)

  • 김지혜;오태영
    • 대한물리의학회지
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    • 제5권1호
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    • pp.53-61
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    • 2010
  • Purpose : The purpose of this study is to compare the distribution of foot pressure, knee and ankle joint angle between treadmill walking and ground walking in normal person. Methods : 18 Person of subject has participated this study, let subject to walk in ground and treadmill in order to gain data of foot distribution and knee, ankle joint angle using by parotec system. and Dartfish system. Walking velocity was constrained by 2Km/h and more 10sec. Date analysis was used by paired-t test using SPSS/PC statistical programs for window. Results : Result show that total contact times has shown symmetry between both legs, and more increase of left foot pressure in treadmill walking. Foot pressure of treadmill walking was significantly decreased in right hind foot and fore foot and hallux area. The ankle joint angle of treadmill walking was significantly decreased in initial contact phase. Conclusion : Results of this study show that foot pressure of treadmill walking was more decreased than ground walking in right hind foot and fore foot, hallux area. And the ankle joint angle of treadmill walking was significantly decreased in initial contact phase.

표면에너지와 거칠기가 응착력에 미치는 영향 (The Effects of Surface Energy and Roughness on Adhesion Force)

  • 나종주;권식철;정용수
    • 대한기계학회논문집A
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    • 제30권11호
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    • pp.1335-1347
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    • 2006
  • Surface energies calculated from measured contact angles between several solutions and test samples, such as Si wafer, $Al_2O_3$, $SiO_2$, PTFE(Polytertrafluoroethylene), and DLC(Diamond Like Carbon) films, based on geometric mean method and Lewis acid base method. In order to relate roughness to adhesion force, surface roughness of test samples were scanned large area and small by AFM(Atomic Force Microscopy). Roughness was representative of test samples in large scan area and comparable with AFM tip radius in small scan area. Adhesion forces between AFM tip and test samples were matched well with order of roughness rather then surface energy. When AFM tips having different radius were used to measure adhesion force on DLCI film, sharper AFM tip was, smaller adhesion force was measured. Therefore contact area was more important factor to determine adhesion force.

치과용 세라믹 임플란트 지대주의 기계적 특성 및 절단면 평가 (Mechanical Properties and Cross-sectional Surface Evaluation of Dental Ceramic Abutment)

  • 황준호;권성민;최성기;성미애;이규복
    • 한국표면공학회지
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    • 제51권5호
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    • pp.309-315
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    • 2018
  • The purpose of this study is to assess the mechanical properties of the ceramic abutment with washer. In this study, ceramic abutment were used, tested with $30^{\circ}$ compression load, shear fatigue, adaptation accuracy test(rotation angle, contact interval), removal torque force test, torsional breaking force test. The $30^{\circ}$ compression load was 729 N, the shear fatigue load was 275 N, adaptation accuracy test of rotation angle was within $3^{\circ}$, contact interval within $10{\mu}m$, and removal torque force test value is $18.88N{\cdot}cm$, torsional breaking force test value is $35.52N{\cdot}cm$. Ceramic abutment with a washer fitted have sufficient mechanical strength and may be substituted for titanium abutment.

리그닌 함유 셀룰로오스 나노섬유로 강화된 폴리락틴산 나노복합재의 제조 및 분석 (Preparation and Characterization of Poly(lactic acid) Nanocomposites Reinforced with Lignin-containing Cellulose Nanofibrils)

  • Sun, Haibo;Wang, Xuan;Zhang, Liping
    • 폴리머
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    • 제38권4호
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    • pp.464-470
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    • 2014
  • A chemo-mechanical method was used to prepare lignin-containing cellulose nanofibrils(L-CNF) from unbleached woodpulps dispersed uniformly in an organic solvent. L-CNF/PLA composites were obtained by solvent casting method. The effects of L-CNF concentration on the composite performances were characterized by tensile test machine, contact angle machine, scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR). The tensile test results indicated that the tensile strength and elongation-at-break increased by 50.6% and 31.8% compared with pure PLA. The contact angle of PLA composites decreased from $79.3^{\circ}$ to $68.9^{\circ}$. The FTIR analysis successfully showed that L-CNF had formed intermolecular hydrogen bonding with PLA matrix.

Pb-Free 도금용액 및 피막의 신뢰성평가 (A Reliability Test for Pb-Free Plating Solution and its Deposit)

  • 허진영;구석본;이홍기
    • 청정기술
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    • 제11권3호
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    • pp.153-164
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    • 2005
  • This study found a reliable evaluation for four kinds of pb-Free plating solutions and it's layers, through pure Sn, SnAg, SnBi and SnCu. These four kind of solutions are widely used to pb-Free plating. Hull-cell, Harring-blum, coverage, throwing power, current efficiency, stability, life-time, composition, hardness, roughness, abrasion, scratch, solderability, corrosion, contact angle, morphology, SIR(Surface insulation resistance) and Whisker test were experimented. Also, Using ICP, XRF, FE-SEM, EDS, temperature/humidity chamber, solderability tester, hardness tester, roughness tester, abrasion tester, salt spray tester, contact angle tester, SIR tester, and microscope. In this paper could be shown the systematic and various analysis for reliability about four kinds of pb-Free plating solutions, processes and it's deposit surface.

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누전차단기 하우징의 내후성에 관한 연구 (A Study on the Weathering of RCD'S Housing)

  • 김창환;신진용;강병철;김상명
    • 한국표면공학회지
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    • 제47권6호
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    • pp.335-340
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    • 2014
  • This study selected an outdoor RCD'S and verified behavior of change in the housing with time. Weathering tests were carried out as outdoor exposure test (90 degrees, 37 degrees) and laboratory test (xenon lamp), and the results were evaluated based on color difference, gloss, contact angle, and optical microscope. This study can provide basic data for standardization of development and performance evaluation on RCD'S housing products.

볼스크류 너트부의 강성 모델링과 불확도 해석 (Modeling and Uncertainty Analysis of Ballscrew Nut Stiffness)

  • 민복기;조뢰;김경호;박천홍;정성종
    • 한국정밀공학회지
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    • 제32권5호
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    • pp.415-422
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    • 2015
  • Ballscrews are important motion transfer and positioning units of industrial machinery and precision machines. Positioning accuracy of the feed drive system depends upon axial stiffness of ballscrew systems. As the nut stiffness depends upon preload and operating conditions, analytical modeling of the stiffness is performed through the contact and body deformation analysis. For accurate contact analysis, the contact angle variation between balls and grooves is incorporated in the developed model. To verify the developed mathematical stiffness model, experiments are conducted on the test-rig. Through the uncertainty analysis according to GUM (Guide to the expression of Uncertainty in Measurement), it is confirmed that the formulated stiffness model has over 85% estimation accuracy. After constructing the ballscrew DB, a quick turnaround system for the nut stiffness estimation has been developed in this research.