• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05c
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• pp.135-139
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• 2001

Contour vibration mode piezoelectric transformers were designed and fabricated to the square plate with size of $27.5{\times}27.5{\times}2.5(2.6,\;3.0)mm^3$ using PNW-PMN-PZT ceramics. Electrical characteristics of the piezoelectric transformer were investigated for fluorescent lamp ballast application. The electrical properties and characteristic temperature rise were measured using oscilloscope and infrared temperature sensor. A 28W fluorescent lamp was successfully driven by the fabricated transformers. After driving the lamp using Power Amplifier for 24 min, the output power, efficiency and characteristic temperature rise of PT2 piezoelectric transformer showed the appropriate values of 28.01 W, 99.43% and $11^{\circ}C$, respectively. The electronic ballast using PT2 piezoelectric transformer showed an excellent output power of 28.85 W and efficiency of 86.3%, respetively.

• Journal of computational fluids engineering
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• v.14 no.4
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• pp.67-77
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• 2009

This paper is a continuation of a recent development on the Hermite-based divergence-free element method and deals with a non-isothermal fluid flow driven by the buoyancy force in a square cavity with temperature difference across the two sides. Two Hermite functions are considered for numerical computations in this paper. One is a cubic function and the other is a quartic function. The degrees-of-freedom of the cubic Hermite function are stream function and its first and second derivatives for the velocity field, and temperature and its first derivatives for the temperature field. The degrees-of-freedom of the quartic Hermite function include two second derivatives and one cross derivative of the stream function in addition to the degrees-of-freedom of the cubic stream function. This paper presents a brief review on the Hermite based divergence-free basis functions and its finite element formulations for the buoyancy driven flow. The present algorithm does not employ any upwinding or a stabilization term. However, numerical values and contour graphs for major flow variables showed good agreements with those by De Vahl Davis[6].

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.847-851
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• 2000

In this study, contour-vibration-mode Pb($Ni_{1/2}$,$W_{1/2}$)$O_3$-Pb(Zr,Ti)$O_3$ piezoelectric transformers for driving a 28W(T5) fluorescent lamp were fabricated to the modified filter structure with ring and dot electrodes which has been developed for application in 455kHz AM radios. The piezoelectric transformers were fabricated to the size of $31.5$\times$31.5$\times$2.5$mm^3$ with the variations of ring/dot electrode area ratio. Driving of piezoelectric transformer was carried out with input region for the ring electrode and output region for the dot electrode. The electrical properties and characteristic temperature rises caused by the vibration were measured at various load resistances. A 28 W fluorescent lamp, T5, was successfully driven by the fabricated transformer. The transformer with ring/dot electrode area ratio of 1.83 exhibited the best properties in terms of output power, efficiency and characteristic temperature rise, 30.95 W, 97.57% and8.3$^{\circ}C$ respectively.

• Journal of the Korean Society for Nondestructive Testing
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• v.30 no.2
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• pp.116-120
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• 2010

The wheelset, an assembly of wheel and axle, is one of important parts in railway bogie, directly related with the running safety of railway rolling stock. In this investigation, the tensile failure behavior of railway axle materials was investigated. The tensile coupons were prepared from the actual rolling stock parts, which were operated over 20 years. The tensile testing was performed according to the KS guideline. During tensile testing, an infrared camera was employed to monitor temperature changes in specimen as well as demonstrate temperature contour in terms of infrared thermographic images. The thermographic images of tensile specimens showed comparable results with mechanical behavior of tensile materials. In this paper, the failure mode and behavior of railway axle materials were provided with the aid of infrared thermography technique.

• Journal of Acupuncture Research
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• v.20 no.5
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• pp.107-117
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• 2003

Objective: This study was examined for effects of acupuncture of Zusanli(ST36) on the facial thermography in health subjects. Methods: The voiunteers who participating in this study had taken rest for 15 mins in room temperature ($19-21^{\circ}C$) before the examination and informed them what to prohibit smoking. drinking and administration of drug for the previous day. The thermography of face was taken using Digital Infrared Thermographic Imaging (D.I.T.I.: Dorex. DTI-16UT1. U.S.A.) by time interval of 35 minutes at 15 min before and 20 min after acupuncture stimuiation. Thermal temperature of Daying(ST5). Juliao(ST3) and Quanliao(SI18) was measured and compared. Results: The results showed that acupuncture of Zusanli(ST36) significantly decreased the Absolute defference of temperature between Daying(ST5) and Juliao(ST3) (p<0.05, Data were represented meant ${\pm}$S.E.M.(n=33)). The results showed that acupuncture of Zusanli(ST36) significantly decreased the Absolute defference of temperature between Quanliao(SI18) and Juliao(ST3)(p<0.01, Data were represented mean${\pm}$S.E.M. (n=33)). But, acupuncture of Zusanli(ST36) particularly decreased the absolute defference of temperature between Daying(ST5) and Quanliao(SI18). Also. it was observed that acupuncture of ST36 decreased variety of the color tone of thermographic contour line and decreased thermal distribution. Conclusions: The results showed that acupuncture of Zusanli(ST36) significantly decreased the absolute defference of temperature of partial facial surface. Hereafter. study about if acupuncture of Zusanli(ST36) significantly decrease the absolute defference of temperature of all the areas of facial surface is requested. Also. continued study of effects of acupuncture of other meridian on the facial thermography is requested.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.6
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• pp.1493-1499
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• 2003

This study was examined for effects of acupuncture of Chok-Samni(ST36) on the facial thermography in health subjects, The volunteers who participating in this study had taken rest for 15 mins in room temperature (19-21 ℃) before the examination and informed them what to prohibit smoking, drinking and administration of drug for the previous day, The thermography of face was taken using Digital Infrared Thermographic Imaging (D.I.T.I. : Dorex, DTI-16UT1, U.S.A.) by time interval of 35 minutes at 15 min before and 20 min after acupuncture stimulation. Thermal temperature of Yangbaek(GB14), Myon-koryo(ST3) and Chichang(ST4) was measured and compared, The results showed that acupuncture of Chok-Samni(ST36) decreased the Absolute difference of temperature between Myon-koryo(ST3) and Chichang(ST4) (p<0,05, Data were represented mean±S,E.M.(n=33)), But, acupuncture of Chok-Samni(ST36) particularly decreased the absolute difference of temperature between Yangbaek(GB14) and Chichang(ST4) and particularly decreased the absolute difference of temperature between Vangbaek(GB14) and Myon-koryo(ST3) (p<0,05, Data were represented mean±S,E.M.(n=33)). Also, it was observed that acupuncture of Chok-Samni(ST36) decreased variety of the color tone of thermographic contour line and decreased thermal distribution. The results showed that acupuncture of Chok-5amni(ST36) significantly decreased the absolute difference of temperature of partial facial surface. Hereafter, study about if acupuncture of Chok-Samni(ST36) significantly decrease the absolute difference of temperature of all the areas of facial surface is requested. Also, continued study of effects of acupuncture of other meridian on the facial thermography is requested.

• Preventive Nutrition and Food Science
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• v.12 no.3
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• pp.160-166
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• 2007

Response surface methodology (RSM) was used for the optimization of the baking process of cookies made with onion powders (onion cookie). Experiments were carried out according to a central composite design, selecting onion powder content $(1.15{\sim}8.86%)$ and baking temperature $(155.9{\sim}184.1^{\circ}C)$ as independent variables and pH, titratable acidity, moisture content, density, spread factor, CIE color parameters $(L^{\ast}-$, $a^{\ast}-$, and $b^{\ast}-values)$, and hardness as response variables. pH decreased with increasing amount of onion powder and baking temperature. Moisture content also decreased as the baking temperature increased. $L^{\ast}-$ and $b^{\ast}-values$ decreased but $a^{\ast}-values$ increased with increasing onion content and baking temperature. Most polynomial models developed by RSM were highly effective to describe the relationships between the studied factors and the responses. Overall optimization, conducted by overlaying the contour plots under investigation, was able to point out the optimal range of the independent variables within which the six responses were simultaneously optimized. The point chosen as representative of this optimal region corresponded to 4.01% onion powder content and $161.84^{\circ}C$ baking temperature. The predicted dependent or response values in the optimal region were: pH＝6.87, moisture content＝2.77%, $L^{\ast}-value＝68.45$, $a^{\ast}-value＝1.98$, $b^{\ast}-value＝34.64$, and spread factor＝9.41.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.5
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• pp.115-123
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• 2010

Cool-down performance after soaking is important because it affects passenger's thermal comfort. The cooling capacity of HVAC system determines initial cool down performance in most cases, the performance is also affected by location, and shape of panel vent, indoor seat arrangement. Therefore, optimal indoor designs are required in developing a new car. In this paper, initial cool down performance is predicted by CFD(computational fluid dynamics) analysis. Experimental time-averaging temperature data are used as inlet boundary condition. For more reliable analysis, real vehicle model and human FE model are used in grid generation procedure. Thermal and aerodynamic characteristics on re-circulation cool vent mode are investigated using CFX 12.0. Thermal comfort represented by PMV(predicted mean vote) is evaluated using acquired numerical data. Temperature and velocity fields show that flow in passenger's compartment after soaking is considerably unstable at the view point of thermodynamics. Volume-averaged temperature is decreased exponentially during overall cool down process. However, temperature monitored at different 16 spots in CFX-Solver shows local variation in head, chest, knee, foot. The cooling speed at the head and chest nearby panel vent are relatively faster than at the knee and foot. Horizontal temperature contour shows asymmetric distribution because of the location of exhaust vent. By evaluating the passenger's thermal comfort, slowest cooling region is found at the driver's seat.

• Journal of the Korean Institute of Gas
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• v.21 no.5
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• pp.45-55
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• 2017

Release and fire/explosion tests of flammable gas are extremely dangerous. Furthermore, it is difficult to select the site where the experiment can be performed. In these reasons, gas flow analysis(CFD) has been used as much as possible. However, with the opening of the Energy Safety Empirical Research Center in Yeongwol-gun, Gangwon-do in October 2016, it was possible to conduct releases and detection tests of small scale combustible gas as well as large scale / high pressure / ultra low temperature experiments. In this study, LPG leaked after the calibration and placement of the sensor, the sensor detected LPG and the data were visualized as a contour map. And the differences between the actual release(28s, max 3.7[m]) and the analysis were analyzed compared to the FLACS analyzed under the same conditions.

• Food Science and Preservation
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• v.10 no.3
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• pp.314-319
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• 2003

This study was conducted to the optimize salting process of eggplant for development new product and enhancement quality for export. Three variables by five level central composite design and response surface methodology were used to determine optimum conditions for salting time, temperature and salt concentration. Optimization of the process was conducted using the combination of the moisture content, salinity and color of surface and inside of salted eggplant. The regression polynomial model was suitable (P>0.05) by Lack-of-Fit analysis with highly significant. To optimize the process, based on surface response and contour plots, the individual contour plots of the response variables were superimposed. The optimum conditions for this process were 6 days and 15$^{\circ}C$ at 30％ concentration under the optimum of restricted variables as moisture content was below 84％, salinity was below 14％, L and b value of surface were 10 to 20 and below 0, L value and b value of inside were 70 to 75 and 16 to 18.