• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.2
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• pp.155-162
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• 1989

This experiment was conducted to investigate the endosperm characteristics of an opaque rice which was derived from an Indica cultivar Pokhareli Mashino. Grain apperance of opaque rice looked similar to the waxy grain, while the blue-color response to the iodine solution was similar to non-waxy endosperm. The shape of starch granules was alike each other, but their size were different each other with the smallest of the opaque rice. Their cristaline structure of starch granules were A type. The content of total protein and most of the amino-acids of opaque rice was about 1.5 times of other varieties. Alkali digestibility of the opaque rice was very low. Total water uptake and hydration rate of opaque rice was similar to non-waxy variety Tongil. Amylogram characteristics such as viscosity, setback and consistency of opaque rice revealed medium value between. waxy and non-waxy rice.

• Journal of the Korean institute of surface engineering
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• v.49 no.3
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• pp.280-285
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• 2016

In this study, we investigated the influences of potassium fluoride(KF) addition on the surface characteristics of plasma electrolytic oxidation(PEO) coating produced on Al alloy. The PEO of marine grade Al alloy(5083 grade) was conducted in KOH 1g/L solution adding different concentrations of KF(0, 1 and 2 g/L) under a galvanostatic regime. With KF addition, unusual behavior was observed on the voltage-time characteristic curves, which can be characterized by the following process: (i) initial rapid increase in voltage (ii) a short plateau after 1st breakdown (iii) gradual increase in voltage (iv) intermittent fluctuation of voltage after 2nd breakdown. The SEM observation revealed irregular surface morphology with KF addition, as compared with one formed without KF addition, which had a reticulate structure. The XRD analysis detected the formation of aluminium hydroxide fluoride hydrate($H_{4.76}Al_2F_{3.24}O_{3.76}$) on surface grown by PEO process with KF. Particularly, at very early stage of the process (~ 120 s), thin film was formed having nanoporous structure, and F element was confirmed on surface by EDS analysis. The thickness and surface roughness of the coating increased with increasing KF concentration. As a result, KF addition was found to be less beneficial influences on PEO of marine grade Al alloy, and therefore needs further research to improve its capability.

• Journal of the Korean institute of surface engineering
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• v.50 no.5
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• pp.322-331
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• 2017

Hydrogen evolution reaction(HER) was studied over $Ni_4Cr$ nanofibers(NFs) prepared by electrospinning method and oxidation/reduction heat treatment for alkaline water electrolysis. The physicochemical and electrochemical properties such as average diameter, lattice parameter, HER activity of synthesized $Ni_4Cr$ NFs could be modified by proper electrospinning process condition and reduction temperature. It was shown that $Ni_4Cr$ NFs had average diameter from 151 to 273 nm. Also, it exhibited the overpotential between 0.419 V and 0.526 V at $1mA/cm^2$ and Tafel slope of -334.75 mV to -444.55 mV per decade in 1 M KOH solution. These results indicate that $Ni_4Cr$ NFs with reduction heat treatment at $600^{\circ}C$ show thinnest diameter and highest HER activity among the other catalysts.

• Journal of the Korean institute of surface engineering
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• v.34 no.1
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• pp.62-67
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• 2001

Green technology is being developed up to a point that is feasible not only in an environmental sense, but also in an economical viewpoint. This paper introduces two case studies that applied $CO_2$ technology into nuclear industry. 1) Nuclear laundry : A laundry machine that uses liquid and supercritical $CO_2$ as a solvent for decontamination of contaminated working dresses in nuclear power plants was developed. The machine consists of a 16 liter reactor, a recovery system with compressors, and storage tanks. All $CO_2$ used in cleaning is fully recovered and reused in next cleaning, resulting in no production of secondary nuclear waste. Decontamination factor is still lower than that in the methods currently used in the plant. Nuclear laundry using $CO_2$ looks promising with technical improvements-surfactants and mechanical agitation. 2) $CO_2$ nozzle decontamination : An adjustable nozzle for controlling the size of dry ice snow was developed. Using the developed nozzle, a surface decontamination device was made. Human oils like fingerprints on glass were easy to remove. Decontamination ability was tested using a contaminated pump-housing surface. About 40 to 80% of radioactivity was removed. This device is effective in surface-decontamination of any electrical devices like detector, controllers which cannot be cleaned in aqueous solution.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.12
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• pp.852-856
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• 2014

$BaTiO_3$ nano powder can be synthesized by hydrate salt method at $120^{\circ}C$ in air. Decreasing the thickness of thick film, the nano dielectric particle is needed in electronic ceramics. However, the synthesis of $BaTiO_3$ nano particle at low temperature in air and their mechanism were not reported enough. And ultrasonic treatment can be tried because of low temperature process in air. Therefore, in this study, the $BaTiO_3$ nano powder was synthesised with the synthesis time and ultrasonic treatment at $120^{\circ}C$ in air. In the synthesis process, the effects of process were evaluated. From the experimental observation, the synthesis mechanism was proposed. The homogeneous $BaTiO_3$ particle was synthesised by KOH salt solution at $120^{\circ}C$ for 1hour. It was conformed that the ultrasonic treatment effected on the increase of synthesis rate. After cutting the salt powder using FIB, $BaTiO_3$ nano particles observed homogeneously in the cross-section of the salt particle.

• Korean Journal of Materials Research
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• v.29 no.10
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• pp.609-616
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• 2019

Oxide coatings are formed on die-cast AZ91D Mg alloy through an environmentally friendly plasma electrolytic oxidation(PEO) process using an electrolytic solution of $NaAlO_2$, KOH, and KF. The effects of PEO condition with different duty cycles (10 %, 20 %, and 40 %) and frequencies(500 Hz, 1,000 Hz, and 2,000 Hz) on the crystal phase, composition, microstructure, and micro-hardness properties of the oxide coatings are investigated. The oxide coatings on die-cast AZ91D Mg alloy mainly consist of MgO and $MgAl_2O_4$ phases. The proportion of each crystalline phase depends on various electrical parameters, such as duty cycle and frequency. The surfaces of oxide coatings exhibit as craters of pancake-shaped oxide melting and solidification particles. The pore size and surface roughness of the oxide coating increase considerably with increase in the number of duty cycles, while the densification and thickness of oxide coatings increase progressively. Differences in the growth mechanism may be attributed to differences in oxide growth during PEO treatment that occur because the applied operating voltage is insufficient to reach breakdown voltage at higher frequencies. PEO treatment also results in the oxide coating having strong adhesion properties on the Mg alloy. The micro-hardness at the cross-section of oxide coatings is much higher not only compared to that on the surface but also compared to that of the conventional anodizing oxide coatings. The oxide coatings are found to improve the micro-hardness with the increase in the number of duty cycles, which suggests that various electrical parameters, such as duty cycle and frequency, are among the key factors controlling the structural and physical properties of the oxide coating.

• Journal of the Korea Institute of Military Science and Technology
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• v.24 no.4
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• pp.382-391
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• 2021

Unsupervised domain adaptation often gives impressive solutions to handle domain shift of data. Most of current approaches assume that unlabeled target data to train is abundant. This assumption is not always true in practices. To tackle this issue, we propose a general solution to solve the domain gap minimization problem without any target data. Our method consists of two regularization steps. The first step is a pixel regularization by arbitrary style transfer. Recently, some methods bring style transfer algorithms to domain adaptation and domain generalization process. They use style transfer algorithms to remove texture bias in source domain data. We also use style transfer algorithms for removing texture bias, but our method depends on neither domain adaptation nor domain generalization paradigm. The second regularization step is a feature regularization by feature alignment. Adding a feature alignment loss term to the model loss, the model learns domain invariant representation more efficiently. We evaluate our regularization methods from several experiments both on small dataset and large dataset. From the experiments, we show that our model can learn domain invariant representation as much as unsupervised domain adaptation methods.

• Knowledge Management Research
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• v.22 no.1
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• pp.1-19
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• 2021

Large-scaled hospital information system projects are often delayed than originally planned. Regarding project management, it is necessary to examine main factors triggering the schedule delay and to analyze the causality of such delay. This study tries to find the delay factors and causal relationship between them based on the case of the hospital information system development project by using the grounded theory method. It turned out that 'unrealistic scheduling' affects overall schedule delays like domino phenomenon, and 'poor analysis of existing systems' leads to poor quality of work analysis while 'poor subsystem integrated interface' triggers poor design quality. This study found out the factors affecting the delay of a project, analyzing cause-and-effect relationships between them in the academic side. From the practical view, it shows a solution to minimize delays in the project schedule for each of SI companies, hospitals and project managers.

• Korean Journal of Veterinary Service
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• v.44 no.4
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• pp.283-290
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• 2021

This is a study on the improvement of the chemical treatment method of the livestock carcass treatment newly introduced in the livestock infectious disease prevention method in order to improve the problems of the existing burial-centered carcass treatment method when a livestock infectious disease occurs. It was conducted to establish detailed treatment standards for the chemical treatment method of pig carcasses based on the results of proof of the absence of infectious diseases in pigs. After inoculating pig carcasses with 10 pathogens (6 viruses [FMDV, ASFV, CSFV, PCV2, PRRSV, PEDV] and 4 bacteria [Lawsonia intracellularis, Clostridium perfringens type C, E. coli, Salmonella Typhimurium]) It was treated at 90℃ for 5 hours in a potassium hydroxide (KOH) liquid solution corresponding to 15% of the body weight. This method liquefies all cadaveric components and inactivates all inoculated pathogens. Based on these results, it was possible to prove that chemical treatment of pig carcasses is effective in killing pathogens and is a safe method without the risk of disease transmission. Although there are problems to be solved in the processing and operation of the chemical treatment products of livestock carcasses, the chemical treatment method of livestock carcasses can be suggested as an alternative to the current domestic burial-centered livestock carcass treatment method, preventing environmental pollution, and contributing to public health.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.2A
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• pp.223-231
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• 2008

This research presents a new maintenance planning method for deteriorating bridges considering simultaneously the minimization of the maintenance cost and maximization of the bridge performance. Optimal maintenance planning is formulated as a multi-objective optimization problem that treats the maintenance cost as well as the bridge performance such as the condition grade of the bridge deck, girder and pier. To effectively address the multi-objective optimization problem and decision making process for the obtained solution set, we apply a genetic algorithm as a numerical searching technique and adopt a preference-based optimization method. A numerical example for a typical 5-span prestressed concrete girder bridge shows that the maintenance cost and the performance of the bridge can be balanced reasonably without severe trade-offs between each objectives.