• Asian-Australasian Journal of Animal Sciences
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• v.13 no.1
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• pp.10-18
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• 2000

This paper describes the magnetic orientation of the intact and demembranated bull sperm treated by DTT or heparin in a 5,400 G static field. Semen samples collected from four bulls (Japanese Black) were mixed to the same sperm density. One percentage triton X-100 was used to extract the plasma membrane. The intact and demembranated sperm suspensions were treated with 20, 200, 2,000 mM DTT, 100, 1,000 or 10,000 units heparin solutions at $4{^{\circ}C}$ for 6 days. The decondensation of the sperm nuclei treated by DTT or heparin was examined by measuring the sperm head area at 1, 3, and 6 days. After measuring the area, each sperm sample was exposed to a 5,400 G static magnetic field generated by Nd-Fe-B permanent magnets for 24 hours at room temperature. Results showed that the decondensation of bull sperm nuclei was not induced by the heparin treatment, however, incomplete decondensation was induced by the DTT treatment. During the magnetic orientation, bull sperms treated by DTT or heparin had low percentages of long axis perpendicular to the magnetic lines of force. However, different aspects were obtained for long axis perpendicular orientations following treatment of DTT or heparin. Through the DTT treatment, the decline of long axis perpendicularly oriented percentages was due to the increase of long axis parallel orientation with the head of the flat plane perpendicular to the magnetic lines of force, whereas, using the heparin treatment, the decline of long axis perpendicular orientation was due to the increment of long axis parallel orientation with the head of the flat plane parallel to the magnetic lines of force. Also, percentages of the head of the flat plane perpendicular were decreased by the heparin treatment. These findings suggest that maintaining the structure of protamine in the chromatin is necessary for the sperm head to orient with its flat plane perpendicular, and maintaining the disulfide bond in the chromatin is necessary for the long axis of sperm to orient perpendicularly.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05e
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• pp.23-26
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• 2003

The flat transformer, typically, has a number of parallel single turn secondary windings. Each secondary winding is coupled to the same primary winding. Therefore, the current in each secondary winding is equal to the ampere-turns in the primary winding, and to each other. These characteristics are particularly advantageous where parallel rectifiers are used. The windings share the current equally, with no need for ballast resistors or other added components. In this study, the ferrite magnetic core samples of Mn-Zn system for the Flat transformer are manufactured and the electrical and magnetic characteristics of its tested. The density of sample FO2-2 sintered at $1350^{\circ}C$ is $4.00kg/m^3$, which shows the good microstructural state. The initial permeability and saturation flux density of FO2 at room temperature is 2700 and 510mT, individually. The power loss of FO2 samples at 250kHz have been ranged $350kW/m^3$ to $80kW/m^3$ with temperature. And the minimum power loss of sample FO2-2 showed at $70^{\circ}C$, which property seems very positive to apply for a flat transformer.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.12
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• pp.1335-1341
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• 2011

The purpose of this research is to investigate how separated and reattached flow affects mass transfer, by comparing the local mass transfer characteristics on an inclined flat plate with those on a parallel flat plate. The local mass transfer coefficients for the flat plate were measured using the naphthalene sublimation technique; the inclined angle of the flat plate was varied from $-10^{\circ}$ to $10^{\circ}$ at $5^{\circ}$ intervals, and the free-stream velocity was varied from 2m/s to 15m/s. At positive inclined angles, the local Sherwood numbers decreased gradually because the boundary-layer thickness increased. On the other hand, for negative inclined angles, the local Sherwood numbers assumed the minimum value at the separation point of the recirculation flow and the maximum value at the reattachment point. The average Sherwood numbers for both positive and negative inclined angles were lower than those in the case of the parallel plate.

• Journal of ILASS-Korea
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• v.13 no.1
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• pp.9-15
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• 2008

This experimental study was carried out to examine the heat transfer characteristics of impinging air jet on a flat plate with a set of right angled triangle rods. Each right angled triangle rod in the array was positioned normal to the flow direction and parallel to the flat plate surface. The clearances from a right angled triangle rod to flat plate surface (C=1, 2 and 4 mm) and the distance from nozzle exit to flat plate (H=100 and 500 mm) were changed for the pitch between each right angled triangle rods (P=40 mm). As a result, heat transfer shows best performance at the clearance of C=1 mm, in case clearance changed, and the average heat transfer enhancement rate increased up to 47% compared to the result of a flat plate without a right angled triangle rod.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.405-406
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• 2006

Recently, the flat display modules such as plasma or TFT-LCD employ thin crystallized panels which are normally weak to high level transient mechanical energy inputs. As a result, anti-shock performance is one of the most important design specifications for TFT-LCD modules. However, most of large display module designs are generated based on engineers own experiences. Also, a large-scale analysis to evaluate complex material and structural behaviors is one of interesting topic in diverse engineering and scientific fields. The utilization of massively parallel processors has also been a recent trend of high performance computing. The objective of this paper is to introduce a parallel process system which consists of general purpose finite element analysis solver as well as parallelized PC cluster. The parallel processing system is constructed using thirty-two processing elements and the finite element program is developed by adopting hierarchical domain decomposition method. In order to verify the efficiency of the established system, an impact analysis on thin and complex sub-parts of flat display modules is performed. The evaluation results showed a good agreement with the corresponding reference solutions, and thus, the parallel process system seems to be a useful tool fur the complex structural analysis such as IT related products.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.3
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• pp.533-541
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• 2001

In this paper, we proposed lowpass filter using all-pass sums of flat delay characteristics. this filter consisted of all-pass filter of parallel structure, the general analog filter is impossible to adjust the phase and the delay, using the Proposed filter, it has advantage to adjust them. And, we compared and analyzed this filter with passband width and magnitude characteristics, and the relation of group delay characteristics and cut-off frequency. Also, in order to obtain desired cut-off frequency, forming the weighing, we obtained desired cut-off frequency and group delay characteristics.

• Transactions of Materials Processing
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• v.29 no.2
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• pp.113-117
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• 2020

Various parameters are involved in the frictional behavior of steel sheet during stamping. We performed various tests in order to investigate the influence of tool surface texture directionality upon the resulting friction in sheet forming processes. Four different tools were manufactured which gave us a range of roughness for both parallel and transverse texture directions. Each of the tools was examined in flat type friction tests under identical test conditions. The tool with the transverse surface texture produces significantly lower levels of friction than the tool with parallel texture direction. Considering the lubrication mechanism associated with transverse texture, one can imagine the lubricant being constantly supplied from the reservoir of the micro valley to the point of contact and hence producing the lower levels of friction seen.

• Solar Energy
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• v.6 no.2
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• pp.62-69
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• 1986

An analysis is made of the fully developed laminar flow and heat transfer in a parallel flat plate with heated rectangular block arrays to investigated the influence of bouyancy force. The shrouds is considered as adiabatic, while the heated block surface transmit a uniform rate of heat flux per unit axial length. The governing equations for velocity and temperature are solved by SIMPLE(Semi-Implicit Method Pressure Linked Equation) algorithm. Detailed velocity and temperature fields and overall heat transfer on wide range of Rayleigh number and various aspect ratios of heated rectangular blocks are computed. The result show that bouyancy leads to a significient enhancement in heat transfer along with a smaller increase in pressure drop, with the great enhancement found when the aspect ratio is 3.0.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.6
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• pp.781-788
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• 2003

In the present study, the heat and flow characteristics of a parallel-flow heat exchanger are numerically analyzed by using three-dimensional turbulent modeling. Heat transfer rate and pressure drop are evaluated using the concept of the efficiency index by varying the locations, the shapes and angles of inlet/outlet, and the protrusion height of flat tube. It is found that negative angle of the inlet improves the heat transfer rate and pressure drop. Results show that the locations of the inlet and outlet should be toward the right side and the left side to the reference model, respectively, in order to enhance the heat transfer rate and pressure drop. Increasing the height of the lower header causes pressure drop to decrease and yields the good flow characteristics. The lower protrusion height of flat tube shows the improvement of the heat transfer rate and pressure drop. The heat transfer rate is greatly affected by the parameters of outlet side such as the location and angle of the outlet. However, the pressure drop is influenced by the parameters of inlet side such as the location and angle of inlet and the height of the header.

• Journal of the korean Society of Automotive Engineers
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• v.15 no.3
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• pp.68-74
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• 1993

The mixed convection heat transfer has been studied numerically for misaligned and parrallel arrays of two flat plates at 100.leg.Re.leg.700, 0.1.leg.B.leg.1.0, 0.2.leg.leg.PHI.$_{R}$.leg.1Gr=10$^{4}$ and Pr=0.71. For misaligned plates and parallel plates, the optimum plate spacings move to the narrow spacing as Reynolds number and .PHI.$_{R}$ increase and can be expressed by the correlation equations at Gr=10$^{4}$. The optimum plate spacings for parallel plates sharply move to the narrow spacing compared with misaligned plates. The maximum mean Nusselt number of parallel plates shows higher value than that of misaligned plates and can be expressed by the correlation equations at Gr=10$^{4}$.EX>.