• Title/Summary/Keyword: Thin sheet

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Improvement of anti-corrosive property for alloy plated steel sheet by UV curable organic-inorganic hybrid coatings (합금도금강판 내식성 향상을 위한 UV 경화형 유무기 하이브리드 코팅)

  • Park, Jongwon;Lee, Kyunghwang;Na, Hyunju;Park, Byungkyu;Nam, Yeungsub;Hong, Shinhyub
    • Corrosion Science and Technology
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    • v.12 no.1
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    • pp.27-33
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    • 2013
  • According to its merits about high curing speed and low emission of volatile organic compounds, UV curable inorganic-organic coating technology has been developed as an alternative for toxic and carcinogenic chromate-based treatments for years. It is consistently observed that ultra-thin films offer excellent corrosion protection as well as paint adhesion to metals. Based on the tetra-ethylorthosilicate(TEOS) and methacryloxypropyl trimethoxysilane(MPTMS), inorganic sol was synthesized and formed hybrid networks with UV curable acrylic monomer, 6-hexanediol diacrylate(HDDA), trimethylolpropane triacrylate(TMPTA), pentaerylthritol triacrylate(PETA). Several methods were used to test their properties such as salt spray test, potentiodynamic measurement, tape peel test, etc. It was shown that anti-corrosive property and stability of storage were affected by the molecular ratios of inorganic and organic compounds. It was not only the stability of storage, but had a excellent anti-corrosive, paint adhesive, and anti-solvent properties in a final molar ratios of 0.6/0.04/0.86/0.005 (TEOS/MPTMS/Acetone/HNO3) and 0.08/0.106/0.081/0.02 (TMPTA/HDDA/PETA/photo initiator).

A Study on Evaporative Characteristics of Multi-component Mixed Fuels Using Mie Scattered Light and Shadowgraph Images (Mie 산란광법 및 Shadowgraph법을 이용한 다성분 혼합연료의 증발특성연구)

  • Yoon, Jun-Kyu;Myong, Kwang-Jae;Jiro Senda;Fujimoto Hajime;Cha, Kyung-Ok
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.30 no.7 s.250
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    • pp.682-691
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    • 2006
  • This study was conducted to assess the effect of mixed fuel composition and mass fraction on spray inner structure in evaporating transient spray under the various ambient conditions. Spray structure and spatial distribution of liquid phase concentration are investigated using a thin laser sheet illumination technique on the multi-component mixed fuels. A pulsed Ar+ laser was used as a light source. The experiments were conducted in a constant volume vessel with optical access. Fuel was injected into the vessel with electronically controlled common rail injector. Used fuel contain $i-octane(C_8H_{18}),\;n-dodecane(C_{12}H_{26})$ and $n-hexadecane(C_{16}H_{34})$ that are selected as low-, middle- and high-boiling point fuel, respectively. Experimental conditions are 25Mpa, 42MPa, 72MPa and 112MPa in injection pressure, $5kg/m^3,\;15kg/m^3\;and\;20kg/m^3$ in ambient gas density, 400K, 500K, 600K and 700K in ambient gas temperature, 300K and 368K in fuel temperature, and different fuel mass fraction. Experimental results indicate that the more high-boiling point component, the longer the liquid phase it were closely related to fuel physical properties, but injection pressure had no effect on. And there was a high correlation between the liquid phase length and boiling temperature at 75% distillation point.

Measurement of Stress and Displacement Fields in Particle Assembly subjected to Shallow Foundation Loading via Photoelasticity Technique (광탄성 기법을 이용한 얕은 기초 하중을 받는 입상체의 응력 및 변위장 측정)

  • Byeon, Bo-Hyeon;Jung, Young-Hoon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.33 no.5
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    • pp.1947-1955
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    • 2013
  • The purpose of this paper is to present an photoelasticity technique for measuring the displacement and stress distribution in particle assembly subjected to shallow foundation loading. Photoelastic measurement technique was employed to visualize the force transmission of a particle assembly. A model assembly bounded by a steel frame was built by stacking bi-dimensional circular particles made of polycarbonate elastomer. Each particle was coated by a thin photoelastic sheet so that the force transmission represented by bright light stripes can be visualized. In a contacted particle, both magnitude and orientation of principal stress difference can also be measured via the photoelasticity technique. The different distributions of the contact stresses at the initial loading and near the failure were quantitatively compared. The photoelastic patterns and displacement fields observed in the pre-failure state disappears immediately after the buckling of confined force chains.

Surface Analysis of Cold Rolled Steel Sheets by X-ray Photoelectron Spectroscopy (X-ray Photoelectron Spectroscopy를 이용한 냉연 강판의 표면 분석 연구)

  • Lee, Do Hyung;So, Jae Choon
    • Analytical Science and Technology
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    • v.7 no.1
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    • pp.115-124
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    • 1994
  • The corroded surface of cold rolled steel sheet in the process of rinsing after alkali-cleaning was examined by means of X-ray Photoelectron Spectroscopy(XPS). In addition, the surface-treated cold rolled steel with 0.05wt% $Na_5P_3O_{10}$ solution for the purpose of preventing the corrosion was examined by means of XPS and the results were compared with those for the non-treated cold rolled steel. It was found that the corroded surface consists of $Fe_2O_3$, FeO and $Fe(OH)_3$ and the thickness of the oxide layer is about $1500{\AA}$. On the other hand, in the case of surface-treated cold rolled steel, the phosphate layer of $60{\AA}$ thickness was found to act as a protective film over the relatively thin Fe oxide layer.

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The characterization of a barrier against Cu diffusion by C-V measurement (C-V 측정에 의한 Cu 확산방지막 특성 평가)

  • 이승윤;라사균;이원준;김동원;박종욱
    • Journal of the Korean Vacuum Society
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    • v.5 no.4
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    • pp.333-340
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    • 1996
  • The properties of TiN as a barrier against Cu diffusion ere studied by sheet resistance measurement, X-ray diffraction, scanning electron microscopy, Auger electron spectroscopy, and capacitance-voltage(C-V) measurement. The sensitivities of the various methods were compared. Specimens with Cu/TiN/Ti/SiO2/Si structure were prepared by various deposition techniques and annealed at various temperatures ranging from $500^{\circ}C$ to $800^{\circ}C$ in 10%H2/90%Ar ambient for hours. As the effectiveness of the barrier property of TiN against Cu diffusion was vanished, the irregular-shaped sports were observed and outdiffused Si were detected on the surface of the Cu thin film. The C-V characteristics of the MOS capacitors varied drastically with annealing temperatures. In C-V measurement, the inversion capacitance decreased at annealing temperature range from $500^{\circ}C$ to $700^{\circ}C$ and increased remarkably at $800^{\circ}C$. These variations may be due to the Cu diffusion through TiN into $SiO_2$ and Si.

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The Delamination and Fatigue Crack Propagation Behavior in A15052/AFRP Laminates Under Cyclic Bending Moment (반복-굽힘 모멘트의 진폭에 따른 A15052/AFRP 적층재의 층간분리 영역과 피로균열진전 거동)

  • Song, Sam-Hong;Kim, Cheol-Ung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.8
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    • pp.1277-1286
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    • 2001
  • Aluminum 5052/Aramid Fiber Reinforced Plastic(Al5052/AFRP) laminates are applied to the fuselage-wing intersection. The Al5052/AFRP laminates suffer from the cyclic bending moment of variable amplitude during the service. Therefore, the influence of cyclic bending moment on the delamination and the fatigue crack propagation behavior in Al5052/AFRP laminate was investigated in this study. Al5052/AFRP laminate composite consists of three thin sheets of Al5052 and two layers of unidirectional aramid fibers. The cyclic bending moment fatigue tests were performed with five different levels of bending moment. The shape and size of the delamination zone formed along the fatigue crack between Al5052 sheet and aramid fiber-adhesive layer were measured by an ultrasonic C-scan. The relationships between da/dN and ΔK, between the cyclic bending moment and the delamination zone size, and between the fiber bridging mechanism and the delamination zone were studied. Fiber failures were not observed in the delamination zone in this study. It represents that the fiber bridging modification factor should turn out to increase and that the fatigue crack growth rate should decrease. The shape of delamination zone turns out to be semi-elliptic with the contour decreased non-linearly toward the crack tip.

Fabrication of Transparent Electrode Film for Organic Photovoltaic using Ag grid and Conductive Polymer (Ag grid와 전도성 고분자를 이용한 인쇄기반 OPV용 투명전극 형성)

  • Yu, Jongsu;Kim, Jungsu;Yoon, Sungman;Kim, Dongsoo;Kim, Dojin;Jo, Jeongdai
    • 한국신재생에너지학회:학술대회논문집
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    • 2011.05a
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    • pp.116.1-116.1
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    • 2011
  • Materials with a combination of high electrical conductivity and optical transparency are important components of many electronic and optoelectronic devices such as liquid crystal displays, solar cells, and light emitting diodes. In this study, to fabricate a low-resistance and high optical transparent electrode film for organic photovoltaic, the following steps were performed: the design and manufacture of an electroforming stamp mold, the fabrication of thermal roll imprinted (TRI) poly-carbonate (PC) patterned films, the manufacture of high-conductivity and low-resistance Ag paste which was filled into patterned PC film using a doctor blade process and then coated with a thin film layer of conductive polymer by a spin coating process. As a result of these imprinting processes the PC films obtained a line width of $10{\pm}0.5{\mu}m$, a channel length of $500{\pm}2{\mu}m$, and a pattern depth of $7.34{\pm}0.5{\mu}m$. After the Ag paste was used to fill part of the patterned film with conductive polymer coating, the following parameters were obtained: a sheet resistance of $9.65{\Omega}$/sq, optical transparency values were 83.69 % at a wavelength of 550 nm.

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Evaluation of Pressure Distribution, Muscle Activity, and Subjective Comfort according to the Baby Carrier Type (아기 띠 종류에 따른 압력분포와 근활성도, 주관적 착용감 평가)

  • Lee, Heeran;Hong, Kyung Hwa
    • Journal of Fashion Business
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    • v.21 no.4
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    • pp.105-115
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    • 2017
  • Continuous lifting and carrying of babies constitutes a serious physical burden, leading to issues such as muscle fatigue and pain in child-care workers. However, there is a lack of research on the pressure and subjective comfort of baby carriers that are commercially available in the market. Therefore, this study was intended to determine the most comfortable and least burdensome type of baby carrier. This was done by analyzing muscle activity and pressure when subjects carried babies using three types of baby carriers. The types of baby carriers evaluated included a 'baby carrier of thin shoulder straps without back support band (X-type)', a 'baby carrier with a back-support band and without a hip sheet (H-type)', and a 'baby carrier with back support band and hip support (H-hip type). The subjective comfort of subjects wearing each type of baby carrier was investigated and compared to the objectively measured data. As a result, the X-type baby carrier showed the heaviest pressure on the shoulders and the subjective comfort was found to not be good. On the waist region, the H-type and H-hip type baby carriers showed significantly less muscle activation than the X-type baby carrier. However, subjects showed a stronger preference for the X-type baby carrier on the waist region, despite greater muscle activation. This appears to be because although the back-support band disperses the weight and thus improves physiological comfort; the wearers feel cramped and thus, lower their psychological comfort.

High functional biodegradable card through annealing (어닐링을 통한 고기능성 생분해성 카드)

  • Sim, Jae-Ho
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.2
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    • pp.280-286
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    • 2020
  • Cards made from PVC and PET materials do not oxidize or decompose readily, so they are generally incinerated or landfilled after use and cause pollution problems, such as environmental hormones and combustion gases during incineration. In addition, there is a problem of environmental pollution because they are discarded as semi-permanent refuse without being decomposed at landfill. This study attempted to solve this problem using polylactic acid (PLA), which is a representative biodegradable material as a substitute material that can solve the issues with these cards. On the other hand, when the thin card core sheet is made from only PLA material, the physical properties of the material are insufficient, such as the low temperature impact strength, high temperature stability, and poor bending properties, so its use is limited. To solve this problem, the compositional ratio of PLA was reviewed, and the optimal biodegradable compound composition was determined through an examination of the compositions, such as crystallization nucleating agents, additives, and nano compound technology. The high functionalization as a biodegradable card was verified through a laminating process using annealing technology.

Summer Algal Communities in the Rocky Shore of the South Sea of Korea -1. Intertidal Communities- (남해의 하계 해조군집 -1. 조간대-)

  • KANG Rae-Seon;JE Jong-Geel;HONG Jae-Sang
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.26 no.1
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    • pp.49-62
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    • 1993
  • Structure of intertidal algal communities of the islands on the South Sea of Korea was studied in summer of 1987 and 1988. The area includes Manjedo, Ch'ujado, Kwantaldo, Munsom, Yosodo, Komumdo, Soridi, Yokchido, Pijindo and Hongdo. Three biologically distinct zones, were commonly recognized in the intertidal bulk of the all examined islands. In the high intertidal zone, only a few species showing thin, tubular and sheet like forms were observed, and the most abundant species was Gloiopeltis spp.. Corallina pilulifera, Hizikia fusiformis and Chondria crassicaulis were most abundant species of the mid intertidal zone, which was formed near the mean sea level. The structure of the low intertidal zone was much more complex than the high and mid, the most abundant species were Laurencia spp. and Sargassum sagamianum. All of the coarsely branched and articulated calcareous species were distributed below mean sea level.

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