• Journal of Environmental Science International
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• v.27 no.7
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• pp.531-541
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• 2018

Road freezing caused by snowfall during wintertime causes traffic congestion and many accidents. To prevent such problems, we developed, in this study, a system to predict road freezing based on weather forecast data and the freezing generation modules. The weather forecast data were obtained from a high-resolution model with 1 km resolution for Jeju Island from 00:00 KST on December 1, 2017, to 23:00 KST on February 28, 2018. The results of the weather forecast data show that index of agreement (IOA) temperature was higher than 0.85 at all points, and that for wind speed was higher than 0.7 except in Seogwipo city. In order to evaluate the results of the freezing predictions, we used model evaluation metrics obtained from a confusion matrix. These metrics revealed that, the Imacho module showed good performance in precision and accuracy and that the Karlsson module showed good performance in specificity and FP rate. In particular, Cohen's kappa value was shown to be excellent for both modules, demonstrating that the algorithm is reliable. The superiority of both the modules shows that the new system can prevent traffic problems related to road freezing in the Jeju area during wintertime.

• Current Photovoltaic Research
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• v.9 no.2
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• pp.36-44
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• 2021

To endorse the reliability and durability of the solar photovoltaic (PV) device several tests were conducted before exposing to the outdoor field in a non-ideal condition. The PV module has high probability that intend to perform adequately for 30 years under operating conditions. To evaluate the long term performance of the PV module in diversified terrestrial conditions, one should use the outdoor performance data. However, no one wants to wait for 25 years to determine the module reliability. The accelerating stress tests performing in the laboratory by mimicking different field conditions are thus important to understand the performance of a PV module. In this review, we will discuss briefly about different accelerating stress types, levels and prioritization that are used to evaluate the PV module reliability and durability before using them in real field.

• Journal of the Korean Solar Energy Society
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• v.22 no.1
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• pp.67-72
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• 2002

Solar Air Systems (SAS) have unique advantages for space heating and tempering ventilation air. Air, unlike water, needs no protection against freezing nor are leaks damaging to the building structure or its contents. In contrast to glazed collector, unglazed steel solar collector may have higher efficiencies over glazed flat collector due to the absence of the glass. Therefore, the monitoring of SAS is so important to evaluate actual performance of SAS for right applications. This study is to provide a testing method with a movable test cell developed in KIER to evaluate the thermal performance of SAS based on international standard method ASHRAE 93-86, "Method of Testing to Determine the Thermal Performance of Solar Collectors". The monitoring tool used advanced technique LabVIEW 6i with portable notebook computer. Sample results have been obtained to access the performance of a reference and a target SAS module. The process and tool introduced here could be used to provide a performance verification data for future implementation study applications.

• Journal of Plant Biotechnology
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• v.50
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• pp.225-231
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• 2023

Cold stress is one of the most vulnerable environmental stresses that affect plant growth and crop yields. With the recent advancements in genetic approaches using Arabidopsis and other model systems, genes involved in cold-stress response have been identified and the key cold signaling factors have been characterized. Exposure to low-temperature stress triggers the activation of a set of genes known as cold regulatory (COR) genes. This activation process plays a crucial role in enhancing the resistance of plants to cold and freezing stress. The inducer of the C-repeatbinding factor (CBF) expression 1-CBF module (ICE1-CBF module) is a key cold signaling pathway regulator that enhances the expression of downstream COR genes; however, this signaling module in Panax ginseng remains elusive. Here, we identified cold-signaling-related genes, PgCBF1, PgCBF3, and PgICE1 and conducted functional genomic analysis with a heterologous system. We confirmed that the overexpression of cold- PgCBF3 in the cbf1/2/3 triple Arabidopsis mutant compensated for the cold stress-induced deficiency of COR15A and salt-stress tolerance. In addition, nuclearlocalized PgICE1 has evolutionarily conserved phosphorylation sites that are modulated by brassinsteroid insensitive 2 (PgBIN2) and sucrose non-fermenting 1 (SNF1)-related protein kinase 3 (PgSnRK3), with which it physically interacted in a yeast two-hybrid assay. Overall, our data reveal that the regulators identified in our study, PgICE1 and PgCBFs, are evolutionarily conserved in the P. ginseng genome and are functionally involved in cold and abiotic stress responses.

• The KSFM Journal of Fluid Machinery
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• v.19 no.3
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• pp.43-47
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• 2016

Pile foundations constructed on extremely cold regions cause serviceability problems of superstructures from repeated actions of ground freezing and thawing. Oil sand module plants are mainly constructed on seasonal frozen ground. Due to the freezing and thawing actions of grounds, vertical movements of piles have been observed. To solve these erratic pile movement problems, thin vertical layer of PET aggregates is installed around the pile shaft to prevent potential unfavorable pile movements. There is no known method to calculate "thin PET aggregate layer" -surrounded pile shaft resistance (capacity) against vertical loads; therefore, this experimental research is conducted. Specifically, in this study, horizontal (normal) pressures on pile shaft were assessed varying PET aggregate layer thickness based on the experiment.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.98-98
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• 2003

Recently, human embryonic stem (hES) cells have become very important resources for ES cell basic research, cell replacement therapy, and other medical applications; thus, efficient cryopreservation methods for these cells are needed. This study examined whether a newly developed minimum volume cooling (MVC) vitrification method, which was tested through cryopreservation of sensitive bovine oocytes, can be used for freezing hES cells. Feeder-free cultured hES cell (MB03) colonies were mechanically dissected into several small clumps following enzymatic treatment. We compared the freezing efficiency of a slow-cooling method using a cryo-module (0.4-0.6C/min, 20-30 clumps/vial) and MVC vitrification using a modified 0.5-ml French mini-straw designated as a MVC straw (>$20,000{\circ}C$/min, 10 clumps/straw) After thawing, in vitro survival of hES cell clumps was higher for MVC-vitrified cells (80.8%, 97/120) than for slow-cooled cells (38.2%, 39/102). Further, the proliferation rate of surviving MVC-vitrified cells was similar to that of control hES cells from 2 weeks after thawing. In addition, vitrified-thawed hES cells demonstrated a normal karyotype, were positively immunostained for surface marker antibodies (AP, SSEA-4 and TRA-1-60) and the Oct-4 antibody, and could differentiate into all three embryonic germ layer cells in vitro. This result demonstrates that hES cell clumps can be successfully cryopreserved by a newly developed MVC vitrification method without loss of human cell characteristics.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.10
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• pp.1377-1384
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• 2003

An analysis has been performed for active thermal control of the KOMPSAT monopropellant rocket engine assembly, i.e., dual thruster module(DTM). The main efforts of this work have been directed at determining proper heater sizes for propellant valves and catalyst beds necessary to maintain their temperatures within specified temperature ranges under KOMPSAT environment and operational conditions. The TAS incorporated with TRASYS thermal radiation analyzer was used to establish a complete heat transfer model which allows to predict the DTM temperature as a function of time. The thermal analysis has been performed in transient mode to verify the appropriate power for catalyst bed heaters necessary to increase catalyst bed temperature to the required value within a specified period of time. Similar analysis has been executed to validate the heater power for the thermostatically controlled primary and redundant heater circuits used to prevent hydrazine freezing, i.e., single fault. Moreover the effect of the radiative property of thermal control coating of heat shield was examined. Thruster firing condition was also simulated for the heat soakback condition. As a consequence, all thermal analysis results for DTM satisfactorily met the thermal requirements for the KOMPSAT DTM under the worst case average voltage, i.e. 25 volt.

• The KSFM Journal of Fluid Machinery
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• v.19 no.3
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• pp.37-42
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• 2016

The demand for wireless technology in plant structure has recently been increasing due to several advantages such as installation cost reduction, easy placement, easy extension and aesthetic benefits. Among the many wireless technologies, ZigBee is one of the most useful for plant structure; a wireless plant networking system can be configured using ZigBee alone. This research proposes a ZigBee to use for extreme cold region and thereby enable integration of wired and wireless plant monitoring systems. In this study, in order to assess the performance of ZigBee measured data by thermocouple were examined based on the results from laboratory tests between existing ZigBee and developed ZigBee. From the experiment results, performance of developed ZigBee in harsh environment can be increased well.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.11
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• pp.1087-1093
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• 2010

The satellite thermal control H/W composed of two parallel channels working for heat pipe (HP) and phase change material (PCM) is suggested for the high heat dissipating component which works intermittently with short duty. In a limited point of view, the HP-PCM device is a kind of off-the-shelf component that requires no dedicated configuration and thermal designs to PCM. Therefore, it can be used with less impact on the program cost and schedule different from most of the PCM applications. In present study the typical honeycomb structure radiator applying the HP-PCM device is designed and the detail thermal math model is developed for numerical analyses. The result comparison between without and with PCM shows that the HP-PCM device redistributes the peak heat around the whole mission period through the alternate melting and freezing of PCM, and, as a result, the maximum and minimum temperatures are effectively alleviated. The drawback of PCM application due to low thermal conductivity can be successfully resolved by means of parallel arrangement of HP channel.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.4
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• pp.569-575
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• 2017

Objective: The objective of this research was to study the electrical properties and quality of frozen-thawed chicken breast meat and to investigate the relationship between these parameters at different times of frozen storage. Methods: Thawed samples of chicken breast muscles were evaluated after being kept in frozen storage at $-18^{\circ}C$ for different periods of time (1, 2, 3, 4, 5, 6, 7, and 8 months). Results: The results showed that water-holding capacity (WHC) and protein solubility decreased while thiobarbituric acid-reactive substances content increased with increasing storage time. The impedance module of samples decreased during 8-month frozen storage. Pearson correlation coefficients showed that the impedance change ratio (Q value) was significantly (p<0.05) related to pH, color, WHC, lipid oxidation and protein solubility, indicating a good relationship between the electrical properties and qualities of frozen-thawed chicken breast meat. Conclusion: Impedance measurement has a potential to assess the quality of frozen chicken meat combining with quality indices.