• 대한기계학회논문집
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• 제8권1호
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• pp.10-17
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• 1984

The critical conditions marking the onset of thermally induced vortices over an inclined iso-thermal plate are investigated using the linear stability theory. The stability equations are simplified by estimating the orders of magnitude of respective terms. The analysis is carried out under the assumption that for the system of large Prandtl numbers temperature disturbances are initiated within the conventional thermal boundary layer of the basic flow. The stability criteria obtained from the present results agree well with those of the existing quasi-parallel flow models. In addition it is found that the critical conditions generate the heat transfer correlation in good agreement with experiments. Therefore, it is suggested that the validity of existing theoretical models will be reexamined.

• Journal of Nutrition and Health
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• 제18권1호
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• pp.55-62
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• 1985

The storage stability of the developed Formula of infant foods was investigated. The results are summarized as follows : When formula A and B were stored at room temperature and refrigeration temperature, there was no remarkable changes in consistency. In frozen state, formula A showed more stability in consistency than formula B and formula A could be stored for 6 months without problems due to retrogradation of starch. The heat treatment of both A and B resulted in the increase of a-value, while L-and b-value showed no such change. But from the 4th month at room temperature, and 5th to 6th month at refrigeration appeared an increase in a -value, hence the browning reaction, while frozen samples did not show noticeable changes in surface color. The heat treatment also caused an increase in POV on both formula. The extent of changes in POV during storage varied with storage temperatures and samples.

• 열처리공학회지
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• 제14권6호
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• pp.345-349
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• 2001

This study has investigated the effect of thermal stability and mechanical property of $Fe_{80-X}P_{10}C_6B_4M_X$(X=2, 4, 6, M=transition metal) amorphous alloys fabricated by the melt-spun process. The glass transition temperature($T_g$), crystallization temperature($T_x$) and hardness increase with decreasing electron concentration (e/a) from about 7.38 to 7.18. The decrease of e/a implies the increase in the attractive bonding state between the M elements and other constituent element. The decrease in a/e leads to the enhancement of the attractive bonding state among the constituent elements which is favorable for the increase in $T_g$, $T_x$ and hardness.

• 열처리공학회지
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• 제25권4호
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• pp.175-180
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• 2012

Role of Ca in grain growth behavior has been investigated in hot-rolled Al-3%Mg and Al-3%Mg-0.5%Ca wrought alloys. When annealed for 1 hr from 723 to 823 K, grain size of the Al-3%Mg alloy increased rapidly above 723 K, whereas grains were relatively stable up to 773 K for the Ca-containing alloy. Grain homogeneity of the Ca-containing alloy was better than that of the Ca-free alloy both in hot-rolled and annealed states. Calculated activation energies for grain growth were 77.6 and 85.9 kJ/mole in the range of 723 to 823 K for the alloys with 0 and 0.5%Ca, respectively. Taking SEM images and EDS results into account, enhanced thermal stability in response to Ca addition would be associated with Al4Ca compounds located along the grain boundaries, which eventually play a role in restricting grain growth at elevated temperatures.

• 한국연소학회지
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• 제18권2호
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• pp.42-50
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• 2013

Linear stability analysis of radiating counterflow diffusion flames is numerically conducted to examine the instability characteristics of cellular patterns. Lewis number is assumed to be 0.5 to consider diffusional-thermal instability. Near kinetic limit extinction regime, growth rates of disturbances always have real eigen-values and neutral stability condition of planar disturbances perfectly falls into quasi-steady extinction. Cellular instability of disturbance with transverse direction occurs just before steady extinction. However, near radiative limit extinction regime, the eigenvalues are complex and pulsating instability of planar disturbances appears prior to steady extinction. Cellular instability occurs before the onset of planar pulsating instability, which means the extension of flammability.

• 한국전기전자재료학회논문지
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• 제35권1호
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• pp.50-57
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• 2022

Reliability of CMOS has been severed under aggressive device scaling. Conventional technologies such as lightly doped drain (LDD) and forming gas annealing (FGA) have been applied for better device reliability, but further advances are modest. Alternatively, electro-thermal annealing (ETA) which utilizes Joule heat produced by electrodes in a MOSFET, has been newly introduced for gate dielectric curing. However, concerns about mechanical stability during the electro-thermal annealing, have not been discussed, yet. In this context, this paper demonstrates the mechanical stability of nanosheet FET during the electro-thermal annealing. The effect of mechanical stresses during the electro-thermal annealing was investigated with respect to device design parameters.

• Journal of Mechanical Science and Technology
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• 제15권10호
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• pp.1451-1460
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• 2001

The critical condition of the onset of buoyancy-driven convective motion of uniformly heated horizontal fluid layer was analysed by the propagation theory which transforms the disturbance quantities similarly. The dimensionless critical time, $\tau$$\sub$c/, is obtained as a function of the Rayleigh number and the Prandtl number. Based on the stability criteria and the boundary-layer instability model, a new heat transfer correlation which can cover whole range of Rayleigh number was derived. Our theoretical results predict the experimental results quite reasonably.

• 한국식품위생안전성학회지
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• 제23권1호
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• pp.68-72
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• 2008

Antimicrobial stability of grape seed extract ($ActiVin^{TM}$), pine bark extract ($Pycnogenol^{(R)}$), and oleoresin rosemary ($Herbalox^{(R)}$) on the growth of Aeromonas hydrophila was investigated in cooked ground beef. When compared to the control, the populations of A. hydrophila were most effectively reduced by 4.06 log CFU/g for 1% $Pycnogenol^{(R)}$ added after cooking at 10 days of refrigerated storage, followed by 3.06 log CFU/g for 1% $Pycnogenol^{(R)}$ added before cooking and 1.36 log CFU/g for $ActiVin^{TM}$. Bacteriostatic and bactericidal activities were observed for $Pycnogenol^{(R)}$ added before and after cooking, respectively. $Pycnogenol^{(R)}$ consists of heat-labile and heat-stable compounds. $ActiVin^{TM}$ and $Pycnogenol^{(R)}$ could be considered for use as multifunctional preservatives in meat and meat products.

• 대한수학회논문집
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• 제23권3호
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• pp.401-411
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• 2008

In this paper, we characterize Sobolev spaces $H^s(\mathbb{R}^n),\;s{\in}\mathbb{R}$ by the initial value of solutions of heat equation with a growth condition. By using an idea in its proof, we also discuss a stability problem for Cauchy functional equation in the Sobolev spaces.

• 한국초전도ㆍ저온공학회논문지
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• 제2권1호
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• pp.35-35
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• 2000

The main issues for the power application of High Tc superconducting tape are lower AC loss and higher stability conditions. HTS tape has large stability margin by high heat capacity of superconductor itself and high temperature margin. But, it can be damaged by continuous heat generation at quench point, because normal zone propagation velocity by generating heat is very low. Here, we analyze the quench propagation characteristics using finite element method for BSCCO-2223 HTS tape.