• 한국전산유체공학회:학술대회논문집
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• 1999.05a
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• pp.192-198
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• 1999

The present study proposes modified temperature-dependent non-Newtonian viscosity model and investigates flow characters and heat transfer enhancement of the viscoelastic non-Newtonian fluid in a 2:1 rectangular duct. The proposed modified temperature dependent viscosity model has non-zero value near the high temperature and high shear rate region while on the existing viscosity models have zero value. Two versions of thermal boundary conditions involving difference combination of heated walls and adiabatic walls are analyzed in this study. The combined effect of temperature dependent viscosity, buoyancy, and secondary flow caused by second normal stress difference are ail considered. The Reiner-Rivlin model is adopted as a viscoelastic fluid model to simulate the secondary flow caused by second normal stress difference. Calculated Nusselt numbers by the modified temperature-dependent viscosity model gives under prediction than the existing temperature-dependent viscosity model in the regions of thermally developed with same secondary normal stress difference coefficients with experimental results in the regions of thermally developed. The heat transfer enhancement of the viscoelastic fluid in a 2:1 rectangular duct is highly dependent on the secondary flow caused by the magnitude of second normal stress difference.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.4
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• pp.202-211
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• 2017

In this study, the exergy that can be reflected in the energetic and economic values was used to assess the heat tariff of a district heating (DH) system instead of the enthalpy. It is difficult to directly apply the exergy to the current heat-charge system because of the complicated calculation; therefore, the difference between the supply and return temperatures was converted to the exergy-temperature difference for the ease of the heat-amount calculation. As a result of the exergy analysis for a DH substation, the exergy-temperature difference did not affect the surrounding temperature and pressure loss. The supply temperature and the maximum difference between the supply temperature and the return temperature exerted the main effect on the exergy-temperature difference. The new heat charge of a DH user was slightly reduced in winter compared with the previous charge, but the heat charges in the other seasons are almost the same. It is concluded from the assessment of the heat tariff for which the exergy is used that this tariff is more feasible for both DH suppliers and consumers compared with enthalpy.

• Journal of Veterinary Clinics
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• v.19 no.1
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• pp.28-36
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• 2002

These studies were carried out to develop some easy-checking thermometers instead of taking temperature of ectum for the farmers to detect easily a diseased animal with fever. Thermometers such as pincher-type, hood-type, raser-type, stick-type, and wrap-type were devised for the experiments. The experimental animals were cattle, horse, swine, aprine, and canine. Temperature-taking parts of the body were ear, shoulder, axilla, gluteal part, and coccygeal part according o the devised thermometer. Rectal temperature was taken at the same time for the comparison of temperature between rectum nd the certain part. The difference of temperature between rectum and shoulder part using eraser-type thermometer for the domestic animals were $3.37^{\circ}C$ for cattle, $1.94^{\circ}C$ for horses, $2.04^{\circ}C$ for swine, $1.27^{\circ}C$ for caprine, $0.9^{\circ}C$ for canine. The difference of temperature between rectum and gluteal part using eraser-type thermometer for domestic animals were $3.46^{\circ}C$ for cattle, $1.98^{\circ}C$ for horses, $2.22^{\circ}C$ for swine, and $1.1^{\circ}C$ for canine. The difference of intra-individual temperature taken by eraser-type thermometer of shoulder and gluteal part were 0.3 and $0.8^{\circ}C$ for cattle, 0.7 and $1.1^{\circ}C$ for horses, 0.6 and $0.7^{\circ}C$ for swine, 0.9 and $1.1^{\circ}C$ for canine. The difference of temperature between rectum and shoulder part taken by hood-type thermometer for cattle was $3.93^{\circ}C$ and the difference of intra-individual temperature was $0.8^{\circ}C$. The difference of temperature between rectum and gluteal part taken by stick-type thermometer for cattle was $3.7^{\circ}C$ and the difference of intra-individual temperature was $0.8^{\circ}C$. The other types of thermometers than the above three were not proved to be reliable to detect temperature of domestic animals. It was concluded that hood-type, stick-type and eraser-type thermometers are recommendable devices of thermometer to detect easily the status of body temperature and that the eraser-type was proved to be a practical one of the thermometers used in this study.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.6 s.237
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• pp.722-729
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• 2005

Design analysis of the solid oxide fuel cell and gas turbine combined power system is performed considering different methods for preheating cell inlet air. The purpose of air preheating is to keep the temperature difference between cell inlet and outlet within a practical design range thus to reduce thermal stress inside the cell. Three different methods considered are (1) adopting a burner in front of the cell, (2) adopting a preheater (heat transfer from the main combustor) in front of the cell and (3) using recirculation of the cathode exit gas. For each configuration, analyses are carried out for two values of allowable maximum cell temperature difference. Performance characteristics of all cases are compared and design limitations are discussed. Relaxation of the cell temperature difference (larger difference) is proved to ensure higher efficiency. Recirculation of the cathode exit gas exhibits better performance than other methods and this advantage becomes more prominent as the constraint of the cell temperature difference becomes more severe (smaller temperature difference).

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.2
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• pp.729-737
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• 2013

The environmental load of concrete pavement can be categorized by temperature and moisture loads, which mean temperature distribution, and drying shrinkage and creep in the concrete slab. In this study, a method calculating the environmental load essential to mechanistic design of airport concrete pavement was developed. First, target area and design slab thickness were determined. And, the concrete temperature distribution with slab depth was predicted by a pavement temperature prediction program to calculate equivalent linear temperature difference. The concrete drying shrinkage was predicted by improving an existing model to calculate differential shrinkage equivalent linear temperature difference considering regional relative humidity. In addition, the stress relaxation was considered in the drying shrinkage. Eventually, the equivalent linear temperature difference due to temperature and the differential shrinkage equivalent linear temperature difference due to moisture were combined into the total equivalent linear temperature difference as terminal environmental load. The environmental load of eight civilian and two military airports which represent domestic regional weather conditions were calculated and compared by the method developed in this study to show its application.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1163-1165
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• 1987

A novel temperature difference-to-frequency converter using two resistance temperature detectors (RTDs) has been developed. The resistance difference of two RTDs is converted into its equivalent inductance to form the resonant circuit of the Colpitts oscillator. The conversion sensitivity of $16\;Hz/^{\circ}C$ and the residual nonlinearity less than 2.15% over the temperature difference range from $35^{\circ}C$ to $155^{\circ}C$ are obtained by the prototype converter. The frequency drift of oscillator itself is ${\pm}0.5\;Hz$. Thus, the minimum detectable temperature difference is estimated to be ${\pm}0.013^{\circ}C$. The proposed converter, except for two RTDs, can be fabricated in monolithic IC form.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.11
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• pp.1282-1285
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• 1988

A novel temperature difference-to-frequency converter using two resistance temperature detectors (RTD) has been developed. The resistance difference of two RTD is converted into its equivalent inductance to form the resonant circuit of the Colpitts oscillator. The conversion sensitivity of 16 Hz/$^{\circ}C$ and the residual nonlinearity less than 2.15% over the temperature difference range from 35$^{\circ}C$ to 155$^{\circ}C$ are obtained by the prototype converter. The frequency drift of oscillator itself is $\pm$ 0.5Hz. Thus, the minimum detectable temperature difference is estimated to be $\pm$ 0.013$^{\circ}C$. The proposed coverter, except for two RTD, can be fabricated in monolithic IC form.

• Journal of Oriental Medical Thermology
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• v.8 no.1
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• pp.7-12
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• 2010

Purpose : The purpose of this study is to know the temperature difference between hysterectomy patients and non-hysterectomy patients. Methods : We studied 45 who had and 45 non-hysterectomy visiting ${\bigcirc}{\bigcirc}$ medical center from January 1st 2010 to December 31st 2010. We measured 3 points temperature of specific acupoints-Chonjung(CV17), Chungwan(CV12), Kwanwon(CV4) by DITI in each group. And then we checked the difference of temperature between CV17 and CV4, CV12 and CV4. For statistics, we used Independent T-test and SPSS version 17.0 for windows. Results : There is no statistically differences between hysterectomy group and non-hysterectomy group on CV17, CV12, CV4 and CV12-CV4 temperature. There is statistically significant difference between group and group on CV17-CV4 temperature. Conclusion : The result showed that the difference between Chonjung(CV17) and Kwanwon(CV4) is higher in group than non-hysterectomy group. Further study will be needed.

• Current Optics and Photonics
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• v.6 no.3
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• pp.297-303
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• 2022

Multiple fiber Bragg gratings (FBGs) have been proposed and demonstrated for gas-flow measurements in a flow channel, using the temperature-difference method. This sensor consists of two FBG temperature sensors and two coil heaters. Coil heaters are used to heat the FBGs. The flow rate of the gas can be obtained by monitoring the difference in the Bragg-wavelength shifts of the two FBGs, which has features that exclude the effect of temperature fluctuations. In this study, experiments are conducted to measure the wavelength shift based on the flow rate, and to evaluate the gas-flow rate in a gas tube. Experimental results show that the sensor has a linear characteristic over a flow-rate range from 0 to 25 ℓ/min. The measured sensitivity of the sensor is 3.2 pm/(ℓ/min) at a coil current of 120 mA.

• Proceedings of the Korea Contents Association Conference
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• 2017.05a
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• pp.101-102
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• 2017

This study of purpose was to evaluate the changes in hands and feet temperature by applying massage and paraffin bath.. The subject of this study was 30 university healthy students. Subjects were divided into paraffin bath group and massages group. The digital infrared thermographic imaging was used for thermographic analysis. The visual analog scale was used for subjective information about the degree of cold sensitivity and cold stress test was used for analyzing the temperature recovery rate. After the interventions showed that temperature difference of the right hand and temperature difference of the left hand are less in the paraffin group than the massage group. When applied paraffin bath and massage to the cold hypersensitivity patient the massage group showed difference in the visual analog scale and the paraffin group showed difference in the temperature of the right hand, left hand, left foot and in the visual analog scale. Paraffin bath treatment seems to be useful to patients with cold hypersensitivity on hands and feet.