• Current Photovoltaic Research
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• v.4 no.2
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• pp.59-63
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• 2016

A key point of a soldering process for photovoltaic (PV) modules is to increase an adhesive strength leading a low resistivity between ribbon and cell. In this study, we intended to optimize a heating condition for the soldering process and characterize the soldered joint via physical and chemical analysis methods. For the purpose, the heating conditions were adjusted by IR lamp power, heating time and hot plate temperature for preheating a cell. Since then the peel test for the ribbon and cell was conducted, consequently the peel strength data shows that there is some optimum soldering condition. In here, we observed that the peel strength was modified by increasing the heating condition. Such a soldering property is affected by a various factors of which the soldered joint, flux and bus bar of the cell are changed on the heating condition. Therefore, we tried to reveal causes determining the soldering property through analyzing the soldered interface.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.2
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• pp.281-287
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• 1999

The turbulent natural convection in the membrane type LNG carrier cofferdam with heating points has been studied by numerical method. As the numerical methods, we introduced the three turbulence model, a standard $k-{\varepsilon}$ model and two case of a low Reynolds number models. The parameters considered for this study ore number and capacity of heating points i.e., $1{\leq}Ns{\leq}12$ and $1.0{\times}10^5{\leq}Qs(W/m^3){\leq}1.0{\times}10^8$. The results of the isotherms and velocity vectors have been represented for various parameters. The temperature and velocity at upper position in the space ore shown to be higher than those at lower position. For obtaining the optimal temperatures, $20{\sim}30^{\circ}C$ in the cofferdam space, the heating capacities show $2.0{\times}10^7W/m^3$ at g-heating points and $1.0{\times}10^7W/m^3$ at 12-points. The mean temperature in the cofferdam space can be expressed as a function of number and capacity of heating points.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.4
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• pp.337-345
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• 2009

This paper investigates the reliability of district heating pipes at thermo-elastic fatigue loading. District heating pipes, subjected to $120^{\circ}C$ and $16kg_f/cm^2$ due to water distributing service through inside the pipes, should endure long term cyclic thermal-mechanical loadings. The heating pipes are the co-centric tubes of steel pipe, poly urethane(PUR) insulator, and high density poly ethylene(HDPE) case. On installation, foam pad is externally wrapped for accommodating stress reduction near the bend sections of pipes. However, there have been frequent reports on the failures of bend sections in the middle of long term service. This study scrutinizes the observed failures near the bend sections through applying the finite element methods. Specially in this study, heating pipes are studied on the influence of foam padding on failures and proposed new designs for reinforced bend without foam pad.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.9
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• pp.110-121
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• 2001

During hot pipe bending using induction heating, the wall of bending outside is thinned by tensile stress. In design requirement, the reduction of wall thickness is not allowed to exceed 12.5%. So in this study, two methods of bending, one is loading of reverse moment and the other is loading of temperature gradient, have been investigated to design pipe bending process that satisfy design requirements. For this purpose, finite element analysis with a bending radius 2Do(outer diameter of pipe) has been performed to calculate proper reverse moment and temperature gradient to be applied. Induction heating process has been analyzed to estimate influence of heating process parameters on heating characteristic by finite difference method. Then pipe bending experiments have been performed for verification of finite element and finite difference analysis results. Experimental results are in good agreement with the results of simulations.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.3
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• pp.131-136
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• 2013

The present study has conducted cycle design and control technology of a water source VRF heat pump system. Previously, study of a simultaneous heating and cooling in an air source VRF heat pump system has been conducted. However, performance data and design methods for simultaneous heating and cooling in a water source VRF heat pump system are limited in the literature, due to various system parameters and operating conditions. In this study, the operating characteristics and performances of a simultaneous heating and cooling heat pump system are carried out, in simultaneous operation modes. Control logics of an EEV are developed for flow rate control to the outdoor unit, and are verified. When the control logics are applied, the simultaneous cooling and heating performances are sufficiently achieved, and system COPs are increased by up to 23.4%.

• Journal of Korean Medicine Rehabilitation
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• v.21 no.4
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• pp.181-190
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• 2011

Objectives: The purpose of this study is to investigate the clinical effects of heating-conduction acupuncture therapy on anterior talofibular ligament injury induced by acute and chronic ankle sprain. Methods: From April 19, 2010 to May 30, 2011 the 79 outpatients who had admitted to department of oriental rehabilitation medicine, Dae-Jeon oriental medical hospital, Dae-Jeon university with ankle sprain were performed heating-conduction acupuncture therapy on anterior taIofibular ligament injury. To evaluate the efficiency of heating-conduction acupuncture therapy, pain threshold with pressure algometer and visual analogue scale(VAS) were applied before treatment and after 1st, 2nd treatment. Results: 1. The pain threshold and VAS score showed significant improvement on acute subacute, chronic anterior talofibular ligament injury group. 2. The difference in pain threshold and VAS score between acute, subacute, chronic phase group was not significant. Conclusions: Heating-conduction acupuncture therapy has clinical effects of pan reduction on patient with anterior talofibular ligament injury.

• Journal of Korean Medicine Rehabilitation
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• v.19 no.4
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• pp.127-134
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• 2009

Objectives : The purpose of this study is to investigate the clinical effects of heating-conduction acupuncture therapy on anterior talofibular ligament injury induced by acute ankle sprain. Methods : From October 31, 2008 to July 21, 2009, the 11 outpatients who had admitted to department of oriental rehabilitation medicine, Dae-Jeon oriental medicine hospital, Dae-Jeon university with acute ankle sprain were performed heating-conduction acupuncture therapy on anterior talofibular ligament injury. To evaluate the efficiency of heating-conduction acupuncture therapy, pain threshold with Pressure algometer and visual analogue scale(VAS) were applied before treatment and after 1st, 2nd treatment. Results : 1. The pain threshold score and the VAS score showed statistical significant improvement after 1st treatment. 2. The pain threshold score and the VAS score showed improvement but had no statistical significance after 2nd treatment. 3. The difference between left and right were not statistical significant in pain threshold score and VAS score. Conclusions : Heating-conduction acupuncture therapy has clinical effects of pain reduction on patient with anterior talofibular ligament injury induced by acute ankle sprain.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.1
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• pp.68-76
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• 2007

As an alternative approach to evaluate the unit heating load for apartment houses, we newly developed and proposed unit building method. The new method, which calculates the heating load of an apartment building as a whole, conceptually corresponds to integral analysis of building heat loss, while the existing unit apartment method to differential analysis. Four typical building models of Korean-style apartment house and two dynamic load calculation programs were selected to validate the present method under realistically imposed conditions. Eight sets of unit heating load calculated respectively by unit building and unit apartment methods showed excellent agreements regardless of building model and simulation program. It is expected that the unit building method can take the place of the unit apartment method due to fewer modeling assumptions as well as less computational efforts. Additional calculations to investigate the effects of various parameters on unit heating load yield good consistencies with known facts, and re-confirm the validity.

• Journal of Korean Medicine Rehabilitation
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• v.20 no.3
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• pp.109-117
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• 2010

Objectives : The purpose of this study is to investigate the clinical effects of heating-conduction acupuncture therapy on lumbago induced by iliolumbar ligament sprain. Methods : From September 25 to December 30, 2009, the 8 outpatients who had admitted to department of oriental rehabilitation medicine, Dae-Jeon oriental medical hospital, Dae-Jeon university, with acute lumbago were performed heating-conduction acupuncture therapy on iliolumbar ligament sprain. To evaluate the efficiency of heating-conduction acupuncture therapy, visual analogue scale(VAS) and short-form McGill pain questionnaire(SF-MPQ) were applied before treatment and after 1st, 2nd treatment. Results : 1.The VAS and SF-MPQ scores showed statistically significant improvement after 1st treatment. 2. The VAS and SF-MPQ scores after 2nd treatment showed better improvement than those of before and 1st treatment, but had no statistical significance compared with those of before and 1st treatment. Conclusions : Heating-conduction acupuncture therapy has clinical effects of pain reduction on patient with acute lumbago induced by iliolumbar ligament sprain.

• Journal of The Korean Astronomical Society
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• v.56 no.2
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• pp.225-229
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• 2023

We investigated an emerging magnetic loop dynamically formed on the Sun, which has the effective footpoint heating source that may play a key role in heating a solar atmosphere with free magnetic energy in it. It is suggested that the heating source could be related to local compression of a plasma in the emerging loop by means of Lorentz force, which converts the magnetic energy to the internal energy of the plasma that is used to reaccelerate a decelerated downflow along the loop, eventually generating the source when the kinetic energy of the downflow is thermalized. By analyzing very high-cadense data obtained from a magnetohydrodynamic simulation, we demonstrate how the local compression is activated to trigger the generation of the heating source. This reveals a characteristic of the emerging loop that experiences a dynamic loop-loop interaction, which causes the local compression and makes the plasma gain the internal energy converted from the magnetic energy in the atmosphere. What determines the characteristic that could distinguish an illuminated emerging loop from a nonilluminated one is discussed.