• Korean Journal of Radiology
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• 제24권8호
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• pp.715-718
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• 2023

• 한국해양공학회지
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• 제22권5호
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• pp.87-93
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• 2008

The objective of this paper is the investigation of the statistical properties of Vickers hardness (HV) of friction welded parts in nickel based super resisting steel, alloy 718 steel. First, we examine the statistical properties on the case of as-welded parts. Several Virkers indentations were made under same nominal conditions. This was repeated for three different applied loads, 100, 200 and 300g with a duration time, 10 second. The arithmetic mean of Vickers hardness in base metal (BM) materials is larger than that of HAZ in all applied loads. The measure of dispersion, that is, the coefficient of variation (COV) for BM and HAZ is decreased by increasing with the applied load. The distribution of Vickers hardness was not found to be symmetric type. The probability distribution of Vickers hardness was well followed Weibull distribution. The shape parameter and the scale parameter (characteristic hardness) are increased by increasing with the applied load, as both BM and HAZ.

• 한국재료학회지
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• 제14권11호
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• pp.813-820
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• 2004

The electrolytic reduction of spent oxide fuel involves the liberation of oxygen in a molten LiCl electrolyte, which is a chemically aggressive environment that is very corrosive for typical structural materials. So, it is essential to choose the optimum material for the process equipment handling molten salt. In this study, corrosion behavior of Haynes 263, 75, and Inconel X-750, 718 in molten salt of $LiCl-Li_{2}O$ under oxidation atmosphere was investigated at $650^{\circ}C\;for\;72\sim360$ hours. At $3\;wt\%\;of\;Li_{2}O$, Haynes 263 alloy showed the highest corrosion resistance among the examined alloys, and up to $8\;wt\%\;of\;Li_{2}O$, Haynes 75 exhibited the highest corrosion resistance. Corrosion products were formed $Li(Ni,Co)O_2,\;LiNiO_2\;and\;LiTiO_2\;and\;Cr_{2}O_3$ on Haynes 263, $Cr_{2}O_3,\;NiFe_{2}O_4,\;LiNiO_2,\;Li_{2}NiFe_{2}O_4,\;Li_{2}Ni_{8}O_10$ and Ni on Haynes 75, $Cr_{2}O_3,\;(Al,Nb,Ti)O_2,\;NiFe_{2}O_4,\;and\;Li_{2}NiFe_{2}O_4$ on Inconel X-750 and $Cr_{2}O_3,\;NiFe_{2}O_4\;and\;CrNbO_4$ on Inconel 718, respectively. Haynes 263 showed local corrosion behavior and Haynes 75, Inconel X-750, 718 showed uniform corrosion behavior.

• Journal of Acupuncture Research
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• 제26권3호
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• pp.11-18
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• 2009

Objectives : This study identified the effects of the acupuncture associated with successful cessation at a smoking-cessation clinic of public health center in an urban area. Methods : The subjects of this study were 1121 patients to the smoking cessation clinic of the Anjung Public Healthcare Center in Pyeongtaek, from June 1, 2007 to December 31, 2008. The 123 patients of them were treated by the auricular acupuncture. The experimental group were treated by the acupuncture, and the control only participated in the smoking-cessation clinic program. The data were analysed by SPSS(version 17.0). Chi-square analysis were conducted to see the different of effects between experimental and control group. Also, to find out the factors that affect the success of smoking cessation, logistic regression and Fisher's exact test were done. Results & Conculusions : 1. As the result of the analysis, it showed that 73.2% of the experimental were able to quit smoking for 4 weeks and 6months. 2. Logistic regression and Fisher's exact test showed that number of Cigarette per day, Nicotine Dependence, CO figure(p=.004<.01), and Number of Acupuncture(p=.000<.001) were the factors that affect the successful smoking cessation. 3. The smoking cessation were more likely to success as patients have lower CO figure(B=-.074), more number of the acupuncture(B=1.718). The more number of acupuncture increased 1 time, the more smoking cessation success did 5.576 times(e$^{(1.718{\times}x)$=e$^{(1.718{\times}1)$ = 5.576). 4. As the result of the analysis between experimental and control group, the success rate have the significance difference(p=.000<.001). 73.2% of the experimental were able to quit smoking, but 45.1% of the control did.

• 한국재료학회지
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• 제8권4호
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• pp.354-358
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• 1998

Inconel 719 선재의 경도에 미치는 냉간신선가공량과 시효시간의 영향을 경도측정과 전자현미경을 사용하여 조사하였다. 고용화처리된 재료의 경도는 245Hzv이었으나 50% 냉간신선가공으로 450Hv까지 증가했다. 경도값은 시효시간이 증가함에 따라 초기에 증가하다 감소하는 것으로 나타났으며, 시효 초기 경도증가는 $\gamma^{"}$과 $\gamma^{'}$ 상의 석출에 의한 것이며, 최고경도 이후의 경도감소는$\gamma^{'}$상이 $\delta$상으로 변태되었기 때문이다. 냉간가공도가 증가함에 따라 최고경도에 이르는 시간은 감소되어 0, 30, 50%가공재들에 대해 각각 30, 10, 5분으로 나타났다. 이는 냉간가공으로 인해 $\gamma^{'}$ / $\gamma^{'}$ 상의 석출이 촉진되었기 때문이다. 50%가공재의 경우 1116K에서 5분 시효로$\Upsilon^{'}$ 및 $\Upsilon^{'}$상들이 석출되었다. 또한 50%가공재에서는 초기경도 이하로 경도값이 감소되었는데, 이와 같은 경도값의 큰 감소는 재결정이 일어났기 때문이다.

• 한국해양공학회지
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• 제28권4호
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• pp.356-362
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• 2014

Wear and corrosion of the engine parts surrounded with combustion chamber is more serious compared to the other parts of the engine because temperature of the exhaust gas in a combustion chamber is getting higher and higher with increasing of using the heavy oil of low quality. Therefore, an optimum repair weldment as well as an available choice of the base metal for these parts are very important to prolong their lifetime in a economical point of view. It reported that there was an experimental result for repair weldment on the forged steel which would be generally used with piston crown material, however, it is considered that there is no study for the repair weldment on the cast steel of piston crown material. In this study, four types of electrodes such as 1.25Cr-0.5Mo, 0.5Mo Inconel 625 and 718 were welded with SMAW and GTAW methods on the cast steel which would be generally used with piston crown material. And the corrosion properties of weld metal, heat affected zone and base metal were investigated using electrochemical methods such as measurement of corrosion potential, anodic polarization curves, cyclic voltammogram and impedance etc. in 35% $H_2SO_4$ solution. In the cases of Inconel 625, 718, the weld metals and base metals exhibited the best and worst corrosion resistance respectively, however, 1.25Cr-0.5Mo and 0.5Mo indicated that corrosion resistance of the base metal was better than the weld metal. And the weld metal welded with electrodes of Inconel 625 revealed the best corrosion resistance among the electrodes, and Inconel 718 followed the Inconel 625. Hardness relatively also indicated higher value in the weld metal compared to heat affected zone and base metal. In particular, Inconel 718 indicated the highest value of hardness compared to other electrodes in the heat affected zone.

• 대한기계학회논문집B
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• 제33권9호
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• pp.718-721
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• 2009

A new progressive advanced approach (Loop thermosyphon Thermoelectric Power generation System) is suggested to optimize heat recovery ability from vehicle exhaust gas. As an initial look at device feasibility, the present new TE system adopted the loop thermosyphon as a cooling heat exchanger. The TE system with loop thermosyphon was investigated in terms of working fluids, instability of system, amount of working fluid, and so on. Basically, the present experimental works have been focused on finding the optimum working condition of the system to improve thermoelectric power output and to obtain stable power generation to operate hybrid vehicles. The present experimental results with the loop thermosyphon TE module shows possibilities as an improved TE system for future thermoelectric hybrid vehicles.

• 방송공학회논문지
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• 제23권5호
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• pp.718-721
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• 2018

최근 차세대 국제 비디오 압축 표준 제정에 딥러닝을 이용하여 비디오 부호화 효율을 향상시키기 위한 다양한 시도가 이루어지고 있다. 본 논문에서는 참조프레임 리스트에 포함된 복원 프레임을 이용하여 현재 프레임의 가상 참조프레임을 딥러닝으로 생성하여 화면 간 예측 부호화에 이용하는 알고리즘을 제안한다. 실험에 따르면 제안 알고리즘은 HEVC 참조 소프트웨어 대비 Random Access 실험 환경에서 평균 1.9%의 BD-rate 감소 효율을 제공한다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.139-142
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• 1995

Inconel 718 is one of the most difficut workpiece for machining, So it is necessary to evaluate the machining characteristics of Inconel 718 In this study, High speed machining of this material was carried out with Tin coated WC ball endmill and TiN coated HSS ball endmill. The cutting force and shape of machined surface and cip type were investigated according to variation of cutting speed,feed rate and depth of cut

• 대한화학회지
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• 제39권5호
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• pp.379-383
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• 1995

Amberlite IRC-718 킬레이트 수지에서의 주석(II)이온의 PSA(phenol sulfonic acid) 리간드에 의한 용리현상을 연구하였다. 0.10 M $Sn^{2+}$ 용액 일정량을 흡착시키고 시료를 녹인 여러 가지 농도의 PSA 용리액으로 용리하면 $Sn^{2+}$이 두 개의 봉우리로 용리되고, 이 두 개의 봉우리 면적은 PSA의 농도에 따라 변한다. 이를 이용하여 $Sn^{2+}$와 PSA간의 착물의 안정도상수를 계산하였다. 그 값은 $2.0{\times}10^{-1}$이었다.