• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.433-439
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• 2001

An experimental study was carried out on the characteristics of the mixed-convection heat transfer from a protruding heat source module which had uniform heat flux and was located on a flat plate in the inclined channel. The effects of the inclined channel(${\varphi}=0{\sim}90^{\circ}$) was studied for the input power($Q=3,\;7W$) and inlet air velocities($V_{i}=0.1{\sim}0.9m/s$). Experimental results indicate that the input power was most effective parameter on the temperature differences between inlet air and module. The effects of the inclined angle was negligible when the inlet velocities were above 0.5m/s and 0.9m/s at Q = 3W, 7W respectively. As the inclined angle of the channel increases, the temperatures of the module are decreased. So we obtained the best condition on the adiabatic board at the vertical channel.

• International Journal of Aeronautical and Space Sciences
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• 제10권2호
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• pp.23-33
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• 2009

The inherent aeromechanical complexity of a rotor system necessitated the comprehensive analysis code for helicopter rotor system. In the present study, an aerodynamic analysis module has been developed as a part of rotorcraft comprehensive program. Aerodynamic analysis module is largely classified into airload calculation routine and inflow analysis routine. For airload calculation, quasi-steady analysis model is employed based on the blade element method with the correction of unsteady aerodynamic effects. In order to take unsteady effects - body motion effects and dynamic stall - into account, aerodynamic coefficients are corrected by considering Leishman-Beddoes's unsteady model. Various inflow models and vortex wake models are implemented in the aerodynamic module to consider wake induced inflow. Specifically, linear inflow, dynamic inflow, prescribed wake and free wake model are integrated into the present module. The aerodynamic characteristics of each method are compared and validated against available experimental data such as Elliot's induced inflow distribution and sectional normal force coefficients of AH-1G. In order to validate unsteady aerodynamic model, 2-D unsteady model for NACA0012 airfoil is validated against aerodynamic coefficients of McAlister's experimental data.

• 대한지구과학교육학회지
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• 제1권1호
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• pp.99-110
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• 2008

The purpose of this study was to develop an instructional module for creativity(lMC) which was mainly based on a unit ('Sun's family' in the 2nd semester of the 5th grade in the textbook), to verify the effect of this module on Elementary student's creativity and attitudes related to science. The subject in this study was two 5th grade classes from J elementary school located in Busan. One of the group took the lessons which were designed for the IMC, and the other group took the normal classes. The effect of this subject for the experimental group and controlled group was verified by post-test: creativity and attitude related to science. The results of this study are as follows. First, the experimental group showed more creativity than controlled group on the post-test. The IMC was more effective to enhance student's creativity than general class. Second, the IMC was effective to enhance student's creativity without the difference in academic ability level. Third, the IMC was effective to enhance student's creativity without the difference in the gender. Fourth, the IMC was more effective to change student's attitude related to science than general class in the module application.

• ETRI Journal
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• 제43권5호
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• pp.891-899
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• 2021

We propose a stray inductance extraction method on power modules of the few-kilovolts/several-hundred-amperes class using only low voltages and low currents. The method incorporates a double-pulse generator, a level shifter, a switching device, and a load inductor. The conventional approach generally requires a high voltage of more than half the power module's rated voltage and a high current of around half the rated current. In contrast, the proposed method requires a low voltage and low current environment regardless of the power module's rated voltage because the module is measured in a turn-off state. Both theoretical and experimental results are provided. A physical circuit board was fabricated, and the method was applied to three commercial power modules with EconoDUAL3 cases. The obtained stray inductance values differed from the manufacturer-provided values by less than 1.65 nH, thus demonstrating the method's accuracy. The greatest advantage of the proposed approach is that high voltages or high currents are not required.

• 대한기계학회논문집B
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• 제26권7호
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• pp.1022-1030
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• 2002

The experiments were performed with a $31{\times}31{\times}7mm^3$ simulated 3-dimensional module on the thermal conductive board of a parallel plate channel. The convective thermal conductance for the path from the module surface directly to airflow and conjugate thermal conductance for the path leading from the module to the floor by way of a module support, then, to the airflow were determined with several combinations of module-support-construction(210, 0.32, 0.021 K/W)/floor-material(398, 0.236W/mK) and channel height(15-30mm). As the result, it was found that the conjugate thermal conductance and the temperature distribution around the module depend on the thermal resistance of the module support, and the channel height. These configurations were designed to investigate on the feasibility of using the substrate as an effective heat spreader in the forced convective air-cooling of surface mounted heat source. The experimental results were discussed in the light of interactive nature of heat transfer through two paths, one directed from the module to the airflow and the other via the module support and the floor to the air.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.471-476
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• 2001

The characteristics of conjugated heat transfer in the inclined channel was experimentally investigated. The simulated module is attached to the bottom of the inclined channel and is heated with constant heat flux. The experimental parameters of this study are input power (Q = 3, 7W), inlet air velocity ($V_{i}=0.1{\sim}0.9m/s$) and inclined channel angle (${\varphi}=0{\sim}90^{\circ}$). The results show that input power was most effective parameter on the temperature differences between module and air. As the inclined channel angle increases, the temperatures of the module are increased. And we obtained the best condition on the conductive board when ${\varphi}=0^{\circ}$.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.1109-1112
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• 2004

This paper presents a high sensitive force sensing module to measure machining forces for a tip-based nanopatterning instrument. The force sensing module utilizing a leaf spring mechanism and a capacitive displacement sensor has been designed to provide a measuring range from 80$\mu$N to 8N. This force sensing module is mounted on a PZT driven in-feed motion stage with 1 nm resolution. The sample can be moved by a X-Y scanning motion stage with 5 nm resolution. In the patterning experiments, the machining forces were controlled and monitored by the force sensing module. Then, the patterned sample was measured by AFM. Experimental results demonstrated that the developed force sensing module can be used as an effective sensing device in the nanopatterning operation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.1090-1095
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• 1992

This paper describes the systematic control method of process information transfer and machine cell control in FMS implementation. We have constructed an experimental FMS computer network and control system. The system hardware consists of host computer to manage process data and information transfer of machine cells, cell control computers to control machine cells(NC lathe, machining center). On the other hand, software is made up of oredr management module, NC program searching and generation module, NC part program error check module and cell control module. In this study, we could arrive at conclusion as following : The first, each task could be accomplihed by the efficient information transfer in hierachical computer network. The second, data base system of part programs and process control data is needed for the efficint information transfer and production management. Lastly, expansion of FMS control system could be achieved by the hierachical and decentralized computer control system.

• 한국태양에너지학회 논문집
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• 제26권1호
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• pp.73-79
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• 2006

The integration of PV modules into building facades or roof could raise PV module temperature that results in the reduction of electrical power generation. Lowering operating temperature of PV module is important in this respect, and PV module temperature should be considered more accurately, for building-integrated PV(BIPV) systems in predicting their performance. This paper describes a BIPV solar roof design and verifies its performance through experiment In relation to the effect of ventilation in space between PV module and roof surface. The results showed that the ventilation in the space had a positive effect in lowering the module temperature of the BIPV solar roof that enhanced the performance of its electricity generation.

• KIEAE Journal
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• 제11권3호
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• pp.69-73
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• 2011

In general, there are two types of PVT module depending on the existence of the glass in front of PV module: glazed and unglazed. On the other hand, the water-type PVT modules can be classified into two types, according to absorber type: the sheet-and-tube absorber PVT module and the fully wetted absorber PVT module. The aim of this study is to analyze the electrical and thermal performance of a water-type PVT module with fully wetted absorber. For this study, a prototype of unglazed PVT module with fully wetted absorber was designed and built, and both the thermal and electrical performances of the prototype module were measured in outdoor conditions. A conventional mono-crystalline Si PV module was tested alongside the PVT module for their electrical performance comparison. The results showed that the thermal efficiency of the PVT module was average 51% and its electrical efficiency was average 14.3% in mean fluid temperature $10-40^{\circ}C$, whereas the electrical efficiency of the conventional PV module was average 12.6%. It is found that the electrical efficiency of the PVT module was improved by approximately 14% compared to that of the PV module. The temperature of PVT module becomes lower due to the cooling effect by the fluid of the absorber. The results proved that the electrical efficiency was higher when the mean fluid temperature was lower.