• Progress in Superconductivity and Cryogenics
• /
• v.13 no.4
• /
• pp.26-29
• /
• 2011

In a High temperature superconducting (HTS) tape with high aspect ratio, the magnetic field applied to the HTS tape can be different considerably within the HTS tape. The current distribution in the HTS tape is generally non-uniform because the current distribution is strongly dependent on the applied magnetic field. Non-uniform current distribution in a HTS tape has not been properly considered when the critical current has been estimated. This paper shows the calculation of critical current of a HTS magnet consisting of pancake windings. Non-uniform distribution of current in the HTS tape is considered during the calculation of the critical current. Results of calculation show the current concentrated in the middle part of the HTS tape which is used for one pancake winding.

• Journal of the Semiconductor & Display Technology
• /
• v.10 no.2
• /
• pp.109-113
• /
• 2011

Hot air flow simulations of the wet station dryer module for the solar cell cleaning were conducted. Air incident angles such as to the substrates ($45^{\circ}$), to the bottom ($90^{\circ}$), and to the wall ($135^{\circ}$) were considered. Based on the simulated velocity and temperature profiles, appropriate incident angle was proposed, and it was well matched to experimental results. Additionally, uniform and non-uniform air hole sizes of the tube were compared for the uniform air flow distribution through the batch.

• Proceedings of the KSME Conference
• /
• 2004.11a
• /
• pp.1231-1235
• /
• 2004

The needs of micro scale thermal detecting technique are increasing in biology and chemical industry. For example, Thermal finger print, Micro PCR(polymer chain reaction), ${\mu}TAS$ and so on. To satisfy these needs, we developed a DTSA(Diode Temperature Sensor Array) for detecting and controlling the temperature on small surface. The DTSA is fabricated by using VLSI technique. It consists of 32 ${\times}$ 32 array of diodes (1,024 diodes) for temperature detection and 8 heaters for temperature control on a 8mm ${\times}$ 8mm surface area. The working principle of temperature detection is that the forward voltage drop across a silicon diode is approximately proportional to the inverse of the absolute temperature of diode. And eight heaters ($1K{\Omega}$) made of poly-silicon are added onto a silicon wafer and controlled individually to maintain a uniform temperature distribution across the DTSA. Flip chip packaging used for easy connection of the DTSA. The circuitry for scanning and controlling DTSA are also developed

• Ocean and Polar Research
• /
• v.25 no.1
• /
• pp.63-74
• /
• 2003

The build-up of the heat field in shallow coastal water due to a point source has been investigated using an analytical solution of a time-integral form derived by extending the solutions by Holley(1969) and also presented in Harleman (1971). The uniform water depth is assumed with non-isotropic turbulent dispersion. The alongshore-flow is assumed to be uni-directional, spatially uniform and oscillatory. Due to the presence of the oscillatory alongshore-flow, the heat build-up occurs in an oscillatory manner, and the excess temperature thereby fluctuates in that course and even in the quasi-steady state. A series of calculations reveal that proper choices of the decay coefficient as well as dispersion coefficients are critical to the reliable prediction of the excess temperature field. The dispersion coefficients determine the absolute values of the excess temperature and characterize the shoreline profile, particularly within the tidal excursion distance, while the decay coefficient determines the absolute value of the excess temperature and the convergence rate to that of the quasi-steady state. Within the e-folding time scale $1/k_d$ (where $k_d$ is the heat decay coefficient), heat build-up occurs more than 90% of the quasi-steady state values in a region within a tidal excursion distance (L), while occurs increasingly less the farther we go to the downstream direction (about 80% at 1.25L, and 70% at 1.5L). Calculations with onshore and offshore discharges indicate that thermal spreading in the direction of the shoreline is reduced as the shoreline constraint which controls the lateral mixing is reduced. The importance of collecting long-term records of in situ meteorological conditions and clarifying the definition of the heat loss coefficient is addressed. Interactive use of analytical and numerical modeling is recommended as a desirable way to obtain a reliable estimate of the far-field excess temperature along with extensive field measurements.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.13 no.5
• /
• pp.1012-1022
• /
• 1989

Numerical analysis has been performed on three-dimensional natural convection in inclined concentric annuli with the nonuniform temperature distribution of the inner cylinder. The governing equations are numerically solved by successive over-relaxation methods for various inclination angles at $R_{a}$=3*10$^{4}$, $P_{r}$=7.0 and $r_{1}$ / $r_{2}$=0.6. Temperature and Nusselt number distributions are obtained and calculated results are compared with those of published uniform temperature distributions. It is found that the mean Nusselt numbers for the nonuniform temperature distributions increase more than those for the uniform temperature distributions by about 9. 6% at .delta.= 0.deg., 7.5% at .delta. = 30.deg. and 4.6% at .delta. = 60.deg.. In the case of .delta. = 0.deg., the maximum local Nusselt numbers on the inner and outer cylinder walls show at .xi. = 0.5, 1.5 of .psio=100 .deg. and .xi. = 0.4, 1.6 of .psi. = 180 .deg.. But in the case of .delta. = 30.deg. and .delta. = 60.deg., the maximum local Nusselt numbers on the inner and other cylinder walls show at .xt. = 0.0 of .psi. = 180 .deg. and .xi. = 2.0 of .psi. = 180 .deg...

• Journal of IKEEE
• /
• v.25 no.1
• /
• pp.64-68
• /
• 2021

We demonstrate an effect of annealing temperature on imprinting process of BiLaO thin film for liquid crystal alignment. BiLaO prepared sol-gel process was deposited by spin coating on a glass substrate, and then transferred to a pre-fabricated aligned pattern which is fabricated on a silicon wafer by laser interference lithography. Thin film was annealed at different temperature of 100, 150, 200, and 250 ℃. From the polarized optical microscopy analysis, the liquid crystal orientation was not uniform at the annealing temperature of 200 ℃ or lower and the uniform liquid crystal alignment characteristics were confirmed at the annealing temperature of 250 ℃. From atomic force microscopy, the pattern was not transferred at a temperature of 200 ℃ or lower. In contrast, the pattern was transferred at 250 ℃. Anisotropy of the thin film was obtained by the alignment pattern transferred at a temperature of 250 ℃, and the liquid crystal molecules could be evenly oriented on the thin film. Therefore, it was confirmed that the liquid crystal alignment process by the imprinting process of the BiLaO oxide film was affected by the annealing temperature.

• Fashion & Textile Research Journal
• /
• v.16 no.1
• /
• pp.167-174
• /
• 2014

The physical properties of textile materials and thermal physiological responses of the human subjects were evaluated with 4 different types of the army combat uniforms including US, German, Korean and general uniforms for this study. 8 male adults were used as the human subjects and the tests were done in the environmental chamber that was $25{\pm}0.1^{\circ}C$ of temperature, $65{\pm}5%$ of relative humidity and below 0.3 m/sec of air velocity. The test protocol consisted the rest period for 20 min., the exercise period for 20 min., the rest period for 20 min., the exercise period under wind condition for 20 min., and the recovery period for 20 min. The human subjects walked with 4.5 km/hr for 10 min., ran 7.5 km/hr for 10 min. during the first exercise period and walked and ran with the same speeds under 3.5 m/sec of the air velocity that simulated outdoor condition during the second exercise period. The test results of the study were as follows; The wind condition affected the skin and microclimate temperature of the human subjects lower compared to without wind condition, but had insignificant effect on the humidity control. The low air permeability of Korean uniform caused blocking the elimination of the humidity from the body and the regulation of body temperature. However, Korean uniforms could be the excellent one with the designs considering the ventilation of the uniforms and the textile fabrics with better air permeability.

• Transactions of Materials Processing
• /
• v.11 no.1
• /
• pp.45-53
• /
• 2002

The forming process of metal matrix composites by die casting and squeeze casting process are limited in size and dimension In term of final parts. The melt strirring method have the problems that the homogeneous distribution of the reinforcements is difficult due to the low weldability and the density difference between the molten metal and the reinforcement. The thixoforming process for metal matrix composites has numerous advantages compacted to die casting, squeeze casting and compocasting. However, for the thixofoming process, the billet with the desired volume fraction must be heated to obtain a uniform temperature distribution over the entire cross-sectional areas. To obtain the reheating conditions of composites, the particulate reinforced metal matrix composites for thixoforming were fabricated by combined stirring process which is simultaneously performed with electro-magnetic stirring and mechanical stirring process. The matrix alloy and reinforcement are used to aluminum alloy(A357) and SiCp with diameter 14, $25{\mu}m$, respectively. The microstructure characteristics were investigated by changing the volume fraction and reinforcement size. The heating conditions to obtain the uniform temperature distribution in cross section area of fabricated metal matrix composites billet are proposed with heating time, the heating temperature and the holding time.

• Journal of Power System Engineering
• /
• v.8 no.3
• /
• pp.36-43
• /
• 2004

The effect of bath composition, plating condition and plating rate on the magnetic property of electroless Co-Cu-P deposits were investigated. With increasing $CuCl_2$ concentration in the bath, plating rate increased, while the Br value of deposit decreased sharply. Deposited surface were inferiority by the increase pH above 10.5, bath temperature higher than $80^{\circ}C$. Plating reaction had been ceased by the increase of pH above 11, bath temperature higher than $90^{\circ}C$ and under $40^{\circ}C$. The Br value of deposit was uniform with various concentration of complexing agent(sodium citrate) in the bath. The Br value of deposit was almost equal to that found by the addition of stabilizer (thiourea) and accelerator(NaF). The Br value of deposit was uniform in plating time(20min) and heat treatment temperature(below $200^{\circ}C$), and were confirmed to have adequate bath stability for practical use.

• Journal of Information Display
• /
• v.1 no.1
• /
• pp.14-19
• /
• 2000

Due to distinct properties of plastic substrates such as poor thermal resistance, non-rigidness and high thermal expansion, it is difficult to fabricate plastic film LCDs by conventional LCD processes. Poor thermal resistance and high thermal expansion of substrates induced deformation of substrates surface, mismatch of thermal expansion between ITO electrodes and substrates resulted in defects in the ITO electrodes during the high temperature process. Defects of ITO electrodes and non-uniform cell gap caused by non-rigid and flexible properties were also observed in the pressuring process. Based on in these observations, we used a newly developed material and fabrication process to prevent deformation of substrates, defects of electrodes and to maintain uniform cell gap. The maximum temperature of the process is limited up to $110^{\circ}C$ and pressure loaded during the process is five times less than conventional one. With these invented processes and materials, we obtained highly reliable Plastic Film STN LCDs whose electro-optical characteristics are better than or equivalent to those of typical glass LCDs.