• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.7
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• pp.414-420
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• 2003

The domestic needs for larger capability of power sources are increasing to cope with the expanding power load which results from the industrial developments & the progressed life style. In summer, the peak load is mainly due to the non-industrial reasons such as air-conditioners and other cooling equipments. To cover the concentrated peak load in stable, the power transmission lines should be more constructed and efficiently operated. The ampacity design of the underground cable system is generally following international standards such as IEC287, IEC60853 and JCS168 which regards the shape of 100% daily full power loads. It is not so efficient to neglect the real shapes of load curves generally below 60~70% of full load. The dynamic (real time) rating system tends to be used with the measured thermal parameters which make it possible to calculate the maximum ampacity within required periods. In this paper, the CTM(Conductor Temperature Monitoring) which is the base of dynamic rating systems for tunnel environment is proposed by a design of lumped thermal network ($\pi$-type thermal model) and distribution temperature sensor attached configuration, including the estimation results of its performances by load cycle test on 345kV single phase XLPE cable.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.10a
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• pp.146-151
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• 2003

Reduced Activation Ferritic/Martenstic (RAFs) are leading candidates for structural materials of D-T fusion reactor. One of The RAFs, JLF-1 (9Cr-2W-V, Ta) has been developed and proved to have good resistance against high-fluency neutrino irradiation and good phase stability. Recently, in order to clarify the strengthening mechanical at high temperature, a new scheme to improve high temperature mechanical properties is desired. Therefore, the creep properties and creep life prediction by Larson-Miller Parameter method for JLF-1 to be used for fusion reactor materials or other high temperature components were presented at the elevated temperatures of $500^{\circ}C$, $550^{\circ}C$, $600^{\circ}C$, $650^{\circ}C$ and $704^{\circ}C$. It was confirmed experimentally and quantitatively that a creep life predictive e벼ation at such various high temperatures was well derived by LMP.

• Journal of Food Hygiene and Safety
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• v.12 no.1
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• pp.55-62
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• 1997

This study was carried out to investigate the microbiological and chemical properties of natural water during storage. The water samples were taken at the time of purchase and the opened bottles and unopened bottles stored at the temperature of 4$^{\circ}C$, 18$^{\circ}C$, and 3$0^{\circ}C$. The bacterial content normally rose to 2.06$\times$102 CFU/$m\ell$ for the unopened bottles and 2.91$\times$102 CFU/$m\ell$ for the opened bottles after 2 weeks of storage, and 1.21$\times$102 CFU/$m\ell$ and 2.64$\times$102, respectively, after 24 weeks of storage. The number of viable cells of bacteria peaked more rapidly at the storage temperature of 3$0^{\circ}C$ than 18$^{\circ}C$. But the total samples were found to be negative for coliforms test during the study period. The average range of pH value was from 7.39 to 7.76. The results showed that the nitrates and chlorides satisfied the Korea Drinking Water Quality Standards during the storage period of 24 weeks. However, the undesirable changes of the taste and odor were detected within 2 weeks and 3 weeks, respectively.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.3
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• pp.179-184
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• 1999

In the past ten years, $LiMn_2O_4$-based spinels have been extensively studied as positive electrode materials for lithium-ion batteries. To improve the cycle performance of spinel $LiMn_2O_4$ as the cathode of 4V class lithium secondary batteries, spinel phases $LiMn_2O_4$ were prepared at various temperatures ranging form 600-900$^{\cire}C$ in air. The results showed that charge.dischare capacity of $LiMn_2O_4$ varied at 1st temperature from $200^{\circ}C to 600^{\circ}C$ increase with increasing temperature. $LiMn_2O_4$ synthesized at 2nd temperature $750^{\circ}C$excellent charge.discharge capacity, efficiency and cyclability compared to the samplesynthesized different temperatures. The value of lst charge.discharge capacity was 121mAh/g, 118mAh/g, Also, the efficiency value was about 97%.

• Conservation Science in Museum
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• v.19
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• pp.83-98
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• 2018

Most preceding studies on museum lighting have focused mainly on illuminance, however this study examines diverse lighting characteristics, including illuminance, luminance, color temperature, and color rendering to allow a more objective evaluation of museum lighting. In particular, issues with existing museum lighting were examined through visual measurement to find an appropriate condition complying with museum lighting standards while providing a pleasant lighting experience for visitors. Although the top priority of museum lighting is to safely protect collections on display, lighting that takes into consideration luminance, color temperature and color randition will allow more effective appreciation as well as safe conservation of the exhibits.

• ETRI Journal
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• v.41 no.6
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• pp.820-828
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• 2019

A highly reliable conductive adhesive obtained by transient liquid-phase sintering (TLPS) technologies is studied for use in high-power device packaging. TLPS involves the low-temperature reaction of a low-melting metal or alloy with a high-melting metal or alloy to form a reacted metal matrix. For a TLPS material (consisting of Ag-coated Cu, a Sn96.5-Ag3.0-Cu0.5 solder, and a volatile fluxing resin) used herein, the melting temperature of the metal matrix exceeds the bonding temperature. After bonding of the TLPS material, a unique melting peak of TLPS is observed at 356 ℃, consistent with the transient behavior of Ag₃Sn + Cu₆Sn₅ → liquid + Cu₃Sn reported by the National Institute of Standards and Technology. The TLPS material shows superior thermal conductivity as compared with other commercially available Ag pastes under the same specimen preparation conditions. In conclusion, the TLPS material can be a promising candidate for a highly reliable conductive adhesive in power device packaging because remelting of the SAC305 solder, which is widely used in conventional power modules, is not observed.

• Proceedings of the Korean Reliability Society Conference
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• 2005.06a
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• pp.339-348
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• 2005

In evaluation of electronic reliability on the PCB(Printed Circuit Board),electrochemical migration is one of main test objects. The phenomenon of electrochemical migration occurs In the environment of the high humidity and the high temperature under bias through a continuous aqueous electrolyte. In this paper, the generating mechanism of electrochemical migration is investigated by using water drop acceleration test under various waters. The waters used in the water drop test are city water, distilled water and ionic water. It found that the generated velocity o of electrochemical migration depended on the temperature of water and the electrolyte quantity which included in the various waters.

• Journal of Radiation Protection and Research
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• v.38 no.3
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• pp.132-137
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• 2013

Cryogenic particle detectors have recently been adopted in radiation detection and measurement because of their high energy resolution. Many of these detectors have demonstrated energy resolutions better than the theoretical limit of semiconductor detectors. We report the development of alpha spectrometer using a micro-fabricated magnetic calorimeter coupled to a large-area particle absorber. A piece of gold foil of $2{\times}2{\times}0.05mm^3$ was glued to the paramagnetic temperature sensor made of sputtered Au:Er film to serve as an absorber for incident alpha particles. We performed experiments with 241Am source at cryogen free adiabatic demagnetization refrigerator (CF-ADR). A high energy resolution of 6.8 keV in FWHM was obtained for 5.5 MeV alpha particles.

• Journal of the Korean Institute of Gas
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• v.25 no.4
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• pp.49-56
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• 2021

Liquefied Petroleum Gas is divided into liquefied gases containing propane (C₃H₈) and butane (C₄H₁₀). The quality of LPG varies greatly depending on the composition of the mixture, so it is important to measure the composition accurately. It is difficult to determine the composition of the mixture because liquid and gas coexist at room temperature. Therefore, the uncertainty in determining the concentration of hydrocarbons by component is high, and there are many problems that differ from the actual content standard. Therefore, it is necessary to develop a mixed liquid propane standard gas for the composition and accurate concentration of hydrocarbon substances. Mixed liquid propane standard gas is manufactured into bellows-type constant-pressure cylinders by ISO-6142 (2015). The homogeneity of the four standard gases manufactured was confirmed to be GC-FID. The manufacturer's uncertainty of expansion was 0.01 % to 0.30 % and homogeneity was 0.03 % to 0.25 %. In this mixed liquid propane standard gas, the relative expansion uncertainty of weight method, manufacturing consistency, cylinder adsorption and long-term stability was developed within 0.26 %-1.3 9% (95% of confidence level, k=2).

• Korean Journal of Optics and Photonics
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• v.19 no.6
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• pp.400-407
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• 2008

An Instrument to measure normal spectral emissivity is built using a Fourier Transform-Infrared (FT-IR) spectrometer. The instrument is composed of four main parts, reference blackbody, sample furnace, optics system, and FT-IR spectrometer. Measurement ranges of temperature and wavelength are $200^{\circ}C{\sim}500^{\circ}C$ and $3.5{\mu}m{\sim}20{\mu}m$, respectively. Measured emissivity of the reference blackbody is greater than 0.9993 with combined relative uncertainty less than 0.69%, which can be considered an ideal blackbody. We studied the emissivity of opaque alumina, graphite, anodized aluminum, and steel (IMS 200). It is shown that emissivity increases with the roughness of the steel (IMS 200) surface.