• Journal of the Korean Society for Heat Treatment
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• v.21 no.6
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• pp.287-292
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• 2008

Dissolution behavior of complex carbonitrides in a Nb-Ti-V microalloyed steel was quantitatively examined by electrical resistivity, transmission electron microscopy (TEM), and optical microscopy. The electrical resistivity increased with solution treatment temperature up to $1250^{\circ}C$ for a holding time of 15 min. But, an increasing rate of electrical resistivity with temperature was obviously decreased above $1150^{\circ}C$. As the solution treatment temperature increases, irregular shaped Nb-rich carbonitrides disappear and cuboidal Ti-rich carbonitrides are observed. Abnormal grain growth occurs above $1250^{\circ}C$ for a holding time of 15 min. The optimal solution treatment temperature of a Nb-Ti-V microalloyed steel was determined as $1200^{\circ}C$ for a holding time of 15 min.

• Journal of Korean Society for Quality Management
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• v.48 no.1
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• pp.215-225
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• 2020

Purpose: The purpose of this study was to show current states of domestic Precision Guided Missile(PGM) by analyzing Live-fire test results using general methods to get the Confidence Levels. Methods: Live-fire test results were used to get Confidence Levels of PGM. The Confidence Levels were derived by two general methods. The first method was Binomial distribution and second was convergence of Hypergeometric distribution and Bayes' rule. Results: The results of this study are as follows; The more Live-fire tests of PGM are performed, the higher Confidence Level of PGM will be estimated. And the number of Live-fire tests are related to a unit price of PGM. This results means that the increase of live-fire test, which is useful data for preparation and evaluation of Development Tests / Operation Tests for PGMs, is only way to enhance the Confidence Levels of each PGMs. Conclusion: This study shows the relationship between the Live-fire tests and Confidence Levels of PGMs and it will be used on Live-fire Test & Evaluation of PGMs for reference.

• International Journal of Control, Automation, and Systems
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• v.6 no.5
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• pp.731-739
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• 2008

The docking and recharging system for a mobile robot must guarantee the ability to perform its tasks continuously without human intervention. This paper proposes two docking mechanisms with localization error-compensation capability for an auto recharging system. The mechanisms use friction forces or magnetic forces between the docking parts of the robot and those of the docking station. It is a structure to improve the allowance ranges of lateral and directional docking offsets, in which the robot is able to dock into the docking station. In this paper, auto-recharging system and the features of the proposed mechanisms are verified with experimental results using simple homing method.

• Macromolecular Research
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• v.17 no.7
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• pp.533-537
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• 2009

This paper introduces a modified electro spinning system for biomedical wound-healing applications. The conventional electrospinning process requires a grounded electrode on which highly charged electro spun ultrafine fibers are deposited. Biomedical wound-healing membranes, however, require a very low charge and a low level of remnant solvent on the electrospun membrane, which the conventional process cannot provide. An electrohydrodynamic process complemented with field-controllable electrodes (an auxiliary electrode and guiding electrodes) and an air blowing system was used to produce a membrane, with a considerably reduced charge and low remnant solvent concentration compared to one fabricated using the conventional method. The membrane had a small average pore size (102 nm) and high porosity (85.1%) for prevention of bacterial contamination. In vivo tests on rats showed that these directly electro spun fibrous membranes produced using the modified electro spinning process supported the good healing of skin bums.

• International Journal of Naval Architecture and Ocean Engineering
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• v.5 no.3
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• pp.376-391
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• 2013

Brackets in ships and offshore structures are added structures that can endure stress concentrations. In this study, a concurrent engineering solution was proposed, and a high strength low carbon cast steel alloy applicable to offshore structures was designed and developed. The yield strength and ultimate tensile strength of the designed steel were 480 and 600 MPa, respectively. The carbon equivalent of the steel was 0.446 with a weld crack susceptibility index of 0.219. The optimal structural design of the brackets for offshore structures was evaluated using ANSYS commercial software. The possibility of replacing an assembly of conventional built-up brackets with a single casting bulb bracket was verified. The casting process was simulated using MAGMAsoft commercial software, and a casting fabrication process was designed. For the proposed bulb bracket, it was possible to reduce the size and weight by approximately 30% and 50%, respectively, compared to the conventional type of bracket.

• Korean Journal of Veterinary Research
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• v.37 no.1
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• pp.185-188
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• 1997

전남대학교 수의과대학에서는 조류 blue-green algae를 먹이로 하여 간질의 중간숙주인 애기물달팽이를 실험실에서 유지시켜 왔으나 조류의 배양에 어려움이 많아서 보다 간편하면서 달팽이의 번식에도 좋은 방법을 고안하고자 노력하였다. $28.5{\times}17{\times}18cm$ 크기의 유리수조에 모래를 1.5cm 높이로 깔고 10개의 꼬막껍질을 그 위에 올려놓은 다음 4리터의 증류수를 부어넣었다. 야외에서 채집한 달팽이의 난괴를 부화시켜 얻은 0.63cm 크기의 어린 달팽이 45마리를 세 그룹으로 나누어 세 개의 수조에서 $20^{\circ}C$의 온도를 유지하면서 사육하였고 먹이로 상추잎을 넣어주었다. 매주 수조바닥의 물 $2{\ell}$를 흡인하여 갈아주면서 상추잎을 바꿔넣었고, 계속해서 공기를 통과시켜 산소를 공급하였다. 이와 동일한 방법으로 실험실에서 조류로 사육하던 17대의 달팽이를 사육하여 그 성적을 비교하였던 바 야외에서 채집한 달팽이의 성장률이 실험실에 적응된 것들에 비하여 약간 떨어졌으나 생존율이나 산란율에서는 큰 차이가 인정되지 않았다. 그래서 1년이 넘도록 이 방법으로 달팽이를 사육하면서 간질의 피낭유충을 생산하고 있다. 꼬막껍질은 서서히 분해하면서 달팽이의 각을 형성하는 물질을 제공하여 생존율을 높게 한 것으로 생각된다. 그리고 수조를 햇볕이 드는 창문 가까이에 놓아두었기 때문에 조류가 자생하여 적은 양이나마 달팽이의 먹이가 되었을 것으로 보인다.

• Journal of the Society of Naval Architects of Korea
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• v.45 no.4
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• pp.426-431
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• 2008

The high-strength low-alloy(HSLA) steels have low carbon contents($0.05{\sim}0.25%$ C) in order to produce adequate formability and weldability, and they have manganese contents up to 1.7%. Small quantities of silicon, chromium, nickel, copper, aluminum, molybdenum are used in various combinations. The results contained in this paper can provide the valuable information on the development of $-40^{\circ}C$ low temperature HSLA. Furthermore, the present experimental data will provide important database for casting steel materials of the offshore structure.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.6
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• pp.121-125
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• 2013

This study was carried out to provide a valuable reference which could reduce heating loss of air-inflated double PO film. Therefore, this study was aimed to choose the best air space thickness and injected air temperature. The characteristics of heat transmission variation at experimental materials were measured and analysed in the laboratory. The experiment was conducted of two layers of PO film, each 0.15 mm tick, sandwiching 110, 175, 225 mm of inflated air with 1 m sides. Environmental control lab was constantly controlled with $-10^{\circ}C$ and experiment chamber was constantly changed with 0, 5, 10, $15^{\circ}C$. The analysis of heat transfer showed that heat transmission does not have a direct correlation with Air Space thickness and injected air temperature. But when inside and outside temperature difference of chamber was great, supply of outside air to Air Space had an advantage at reduction of heating load. It was required to examine accurate analysis at a real greenhouse.

• Journal of Acupuncture Research
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• v.35 no.4
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• pp.187-192
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• 2018

Background: The aim of this study was to compare the effects of different cupping therapy methods combined with Korean medicine treatments for peripheral facial paralysis. Methods: 105 patients treated for peripheral facial paralysis with cupping therapy and other Korean medicine treatment at Gil Korean medicine hospital, Gachon University between May 19, 2014 and June 30, 2018 were selected and their medical charts retrospectively analyzed. 48 patients who met the inclusion criteria were divided into 2 groups: wet cupping (WC) therapy, or dry cupping (DC) therapy combined with Korean medicine treatment. The duration of treatment ranged from 2 weeks for inpatient treatment to 2 months for outpatient treatment. Both WC and DC therapy were performed on TE13, 3 times per week during the treatment period. The effect of cupping therapy was evaluated by using the Gross Grading System of the House-Brackmann (HB score) and the Yanagihara's Unweighted Grading System (Y score). Results: For both WC and DC treatment of symptoms related to peripheral facial paralysis, HB scores showed a significant decrease and Y scores showed a significant increase from baseline to end of treatment, indicating a beneficial improvement in patient symptoms for both WC and DC. Conclusion: In this study, both DC and WC treatment had significant improvements on peripheral facial paralysis symptoms, with WC having significantly greater beneficial effects than DC.

• Journal of the Korean Electrochemical Society
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• v.13 no.2
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• pp.132-137
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• 2010

This study is concerned the electrocatalytic generation of oxygen gas at electrochemically deposited manganese oxide electrode in KOH solution. Manganese oxide nanoparticles electrodeposited onto relatively substrate, e.g glassy carbon, Au, Ti electrode. MnOx is electrodeposited in nanorod structure which cover the overall surface of the substrate. The $\gamma$-MnOOH that is kind of manganese oxide species plays a significant role as a catalytic mediator, which promote 4-electron reduction process. Modified electrodes with electrodeposited manganese oxide structures resulted in significant decrease in the anodic polarization compared with the unmodified electrodes in alkaline media.