• Title/Summary/Keyword: Temperature independent

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Fabrication of Carbon Thin Film by Electrochemical Method (전기화학 Carbon Film 합성)

  • Lee, Sang-Heon
    • Proceedings of the KIEE Conference
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    • 2007.11a
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    • pp.128-129
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    • 2007
  • Electrochemical method of carbon film on silicon substrate in methanol solution was carried out with various current density, solution temperature and electrode spacing between anode and cathode. The carbon films with smooth surface morphology and high electrical resistance were formed when the distance between electrode was relatively wider. The electrical resistance of the carbon films were independent of both current density and solution temperature.

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Fabrication of DLC Using Electrodeposition (전기분해 DLC 합성)

  • Lee, Sang-Heon;Choi, Yong
    • Proceedings of the KIEE Conference
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    • 2007.07a
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    • pp.1265-1266
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    • 2007
  • Electro-deposition of carbon film on silicon substrate in methanol solution was carried out with various current density, solution temperature and electrode spacing between anode and cathode. The carbon films with smooth surface morphology and high electrical resistance were formed when the distance between electrode was relatively wider. The electrical resistance of the carbon films were independent of both current density and solution temperature.

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Equation of State Studies on $MgF_2$at Room Temperature (상온하에서 $MgF_2$에 대한 상태방정식 연구)

  • Young-Ho Kim
    • Journal of the Mineralogical Society of Korea
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    • v.3 no.2
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    • pp.72-78
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    • 1990
  • Polycrystalline MaF2(rutile structure) has been studied up to∼15 GPa under truly hydrostatic pressures in a diamond anvil cell(DAC) at room temperature. Its bulk modulus was determined to 96.0 GPa, from two independent runs using Birch-Murnaghan equation of state with an assumed Ko' of 5.1 from ultrasonic measurements. These are in good agreement with the previously reported values by both ultrasonic and X-ray diffraction meth-ods.

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Optimization for Extrusion Cooking Conditions of Rice Extrudate by Response Surface Methodology (반응 표면 분석방법을 이용한 쌀 압출 성형물 제조조건의 최적화)

  • 이상현;김창근
    • The Korean Journal of Food And Nutrition
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    • v.7 no.2
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    • pp.137-143
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    • 1994
  • To optimize extrusion cooking condition of single screw extuder for production of puffed rice extrudate using response surface methodology (RSM), moisture content, barrel temperature and screw speed were determined from contour maps, showing relationship between dependent (hardness, expansion ratio, water absorption index, water solubility Index, degree of gelatinization) and independent variables. Optimum operational conditions for production of puffed rice extrudate with suitable quality properties were moisture content 17%, barrel temperature 1$25^{\circ}C$ and screw speed 210 rpm, respectively.

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Temperature and Loading-Rate Dependence on the Mechanical Behavior of Carbon Nanotubes (탄소나노튜브의 역학적 거동에 관한 온도와 하중부하속도의 의존성)

  • Jeong Byeong-Woo;Lim Jang-Keun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.7 s.250
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    • pp.809-815
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    • 2006
  • The temperature and loading-rate dependence on the mechanical behavior of single-walled carbon nanotubes under axial compression and torsion is examined with classical molecular dynamics simulation. The critical buckling is found to depend on the temperature and loading-rate. The yielding under torsion is also found to depend on the temperature and loading-rate. But it is shown that the compression and torsional stiffness are independent of the varied temperatures and loading-rates.

Dynamic Rheological Invest igation of Hot Pepper-soybean Paste Mixed with Acetylated Starch: Effect of Storage Time and Temperature

  • Yoo, Byoung-Seung
    • Food Science and Biotechnology
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    • v.17 no.5
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    • pp.1119-1121
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    • 2008
  • The effects of storage time (0, 1, and 2 month) and temperature (5, 15, and $25^{\circ}C$) on the dynamic rheological properties of hot pepper-soybean paste (HPSP) mixed with acetylated starches (AS) were studied by small-deformation oscillatory measurements. Dynamic moduli (G', G", and $\eta^*$) values of HPSP-AS mixtures increased with an increase in storage time and also decreased with increasing storage temperature. However, dynamic moduli values of the control (no added AS) were independent on storage time and temperature. Tan $\delta$ values (ratio of G"/G') in all HPSP samples did not change much with an increase in storage time and temperature. After 2 months of storage, the dynamic moduli of the HPSP-AS mixture samples were much lower than those of the control, indicating that the addition of AS can inhibit the retrogradation that developed over a long period of storage. Structural and rheological properties of HPSP samples seem to be stabilized by the presence of AS.

Temperature Stabilization of Group Index in Silicon Slotted Photonic Crystal Waveguides

  • Aghababaeian, Hassan;Vadjed-Samiei, Mohammad-Hashem;Granpayeh, Nosrat
    • Journal of the Optical Society of Korea
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    • v.15 no.4
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    • pp.398-402
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    • 2011
  • In this paper, we have proposed a principle to design wideband, low dispersion and temperature stabilized slow light structure in slotted photonic crystal waveguide (SPCW). The infiltration of the silicon photonic crystal with polymer will enhance the slow light and increase the group index, whereas the different signs of thermo-optic coefficients of polymer and silicon make the proposed structure stable on temperature variation over $60^{\circ}C$ and improves the group index-bandwidth products of the designed structure. The SPCW structure is modified to maximize the slow light effect and minimize the dependence of the group index and hence the group velocity dispersion to temperature.

Grain growth of the PTC thermistor according to the soaking temperature (PTC 서어미스타 소자의 소성온도에 따른 Grain의 성장상태)

  • 박창엽;이영희
    • 전기의세계
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    • v.31 no.6
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    • pp.437-444
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    • 1982
  • Although several kinds of conduction mechanism of PTC thermistor have been reported, there were few satisfying results. In this paper, the reported conduction mechanism theories were scrutinized and analyzed by using the experimental results. PTC thermistors for this study were manufactured by adding Sb$\_$2/O$\_$3/, AI$\_$2/O$\_$3/, TiO$\_$2/, and SiO$\_$2/ to BaTiO$\_$3/, and by sintering it at different temperatures. In order to analyze the conduction mechanism, R-T characteristics and its frequency dependence of specimens were measured. And also, the structures of specimens were studied. Especially this paper emphasized the explanation of the resistivity characteristics as the grain growth state of PTC thermistor specimens with respect to soaking temperature. According to the results, the resistivity of PTC thermistor whose grain was formed by semiconducting, was independent to the grain size at room temperature. For small and uniform grain size, the slope of the resistivity near the Curie temperature and the resistivity above the Curie temperature became greater and PTCR effect was improved.

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Quantitative Vapor Phase Exciplex Fluorescence Measurements at High Ambient Temperature and Pressure

  • Kim, Tongwoo;Jaal B. Ghandhi
    • Journal of Mechanical Science and Technology
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    • v.17 no.1
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    • pp.157-167
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    • 2003
  • The exciplex fluorescence technique with the TMPD (tetamethyl-Ρ-phenylene-diamine) / naphthalene dopant system was applied in a combustion-type constant-volume spray chamber. A detailed set of calibration experiments has been performed in order to quantify the TMPD fluorescence signal. It has been demonstrated that the TMPD fluorescence intensity was directly proportional to concentration, was independent of the chamber pressure, and was not sensitive to quenching by either water vapor or carbon dioxide. Using a dual heated-jet experiment, the temperature dependence of TMPD fluorescence up to 1000 K was measured. The temperature field in the spray images was determined using a simple mixing model, and an iterative solution method was used to determine the concentration and temperature field including the additional effects of the laser sheet extinction. The integrated fuel vapor concentration compared favorably with the measured amount of injected fuel when all of the liquid fuel had evaporated.

GENERALIZED THERMOELASTICITY WITH TEMPERATURE DEPENDENT MODULUS OF ELASTICITY UNDER THREE THEORIES

  • Ezzat, M.;Zakaria, M.;Abdel-Bary, A.
    • Journal of applied mathematics & informatics
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    • v.14 no.1_2
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    • pp.193-212
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    • 2004
  • A new model of generalized thermoelasticity equations for isotropic media with temperature-dependent mechanical properties is established. The modulus of elasticity is taken as a linear function of reference temperature. The present model is described both generalizations, Lord Shulman (L-S) theory with one relaxation time and Green-Lindsay (G-L) with two relaxation times, as well as the coupled theory, instantaneously. The method of the matrix exponential, which constitutes the basis of the state space approach of modern control theory, applied to two-dimensional equations. Laplace and Fourier integral transforms are used. The resulting formulation is applied to a problem of a thick plate subject to heating on parts of the upper and lower surfaces of the plate that varies exponentially with time. Numerical results are given and illustrated graphically for the problem considered. A comparison was made with the results obtained in case of temperature-independent modulus of elasticity in each theory.