• Advances in materials Research
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• 제5권3호
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• pp.181-192
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• 2016

In this work effect of high energy milling on the structural and electrical properties of $Ba(Fe_{1/2}Ta_{1/2})O_3$ (BFT) ceramic synthesized using standard solid-state reaction method were investigated. X-ray diffraction studies indicated that the unit cell structure for all the samples to be hexagonal (space group: P3m1). FTIR spectra also confirmed the formation of BFT without any new phase. The milled (10 h) BFT ceramic showed the formation of small grain sizes (<$2{\mu}m$) which is beneficial for dielectric applications in high density integrated devices. Besides, the milled (10 h) BFT ceramic sample exhibited superior dielectric properties (enhancement in ${\varepsilon}^{\prime}-value$ and reduction in $tg{\delta}-value$) compared to un-milled one. Impedance analysis indicated the negative temperature coefficient of resistance (NTCR) character. The correlated barrier hopping model (jump relaxation type) is found to successfully explain the mechanism of charge transport in present ceramic samples.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.297-301
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• 2002

High-speed machining generates concenter thermal/frictional damage at the cutting ed rapidly decreases the tool life. This paper I at determining the effect of cutter orienter the cutting environment on tool life, tool mechanism when down milling. In this paper, experiments were carried out in various tool and cutting environments, such as dry, wet compressed chilled air, tool life were measu evaluate machinability in high-speed milli difficult-to-cut material and die steel, Tool measured in horizontal upwards, horiz downwards, vertical upwards and vert downwards. In addition, tool life was measur dry, wet and compressed chilled air. For this a compressed chi1led-air system was manufact The results show that a horizontal cutter ori provided a longer tool life than a vertical orientation. With respect to the cutting envi compressed chilled air increased tool life. H the wet condition decreased tool life due thermal shock caused by excessive cooling high-speed mill ins and the compressed chilled had little effect.

• 한국정밀공학회지
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• 제12권3호
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• pp.5-14
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• 1995

In recent years, the automization of cutting machine tools has been developed very fast. Hance, the in-process detection of cutting condition is very important for automatic manufacturing system in factory. Acoustic Emission(AE) has been widely used in monitoring the cutting conditions, because of high sensitivity of AE signal and low cost of AE equipment. This experimental study deals with the relations between AE signal, cutting force charcteristics and tool wear in the machining of SUS304. Face milling operation is used for the analysis between tool wear and AE signal.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.440-441
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• 2006

Several titanate powders ($Al_2TiO_5,\;SrTiO_3$, etc.) were synthesized by an ethylene glycol solution route. Titanium isopropoxide and nitrate salts were dissolved in stoichiometric proportions in liquid-type ethylene glycol without any precipitation. The parent precursor sols were dried to porous gels, and then the gels were calcined and crystallized. All synthesized titanate powders had stable crystallization behavior at low temperature and high specific surface area after a simple ball-milling process. A three-component PZT $(Pb(Zr_{0.52}{\cdot}Ti_{0.48})O_3)$ powder was also synthesized successfully by the ethylene glycol method. In this study, the characteristics of the multi-component titanate powders by the ethylene glycol method are examined.

• 한국식품과학회지
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• 제50권5호
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• pp.549-554
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• 2018

본 연구에서는 일반 메밀과 쓴 메밀의 제분 분획 별(겉껍질, 겨, 가루) 에탄올 추출물의 항산화 성분 함량을 분석하고, 항산화 활성을 시험관과 세포 수준에서 확인하였다. 그 결과, 일반 메밀보다 쓴 메밀에서 총 폴리페놀 및 총 플라보노이드 함량이 월등히 높았으며, 항산화 물질로 주된 성분은 루틴으로 확인되었고, 에탄올 추출과정에서 루틴이 퀘세틴으로 일부 분해되는 것으로 나타났다. 또한 식용 부위인 가루 분획보다 겨 분획에서의 항산화 성분 함량이 높은 것으로 분석되어 겨 분획의 항산화 기능성 소재로 개발의 필요성을 제시하였다. 한편 시험관 및 세포수준에서 항산화 효과를 확인한 결과, 일반 메밀보다 쓴 메밀에서의 항산화 활성이 유의적으로 높았으며, 특히 쓴 메밀 겨 분획의 항산화력이 우수한 것으로 나타났다. 메밀 추출물을 산화스트레스 유발 전, 후 처리한 경우 모두에서 항산화 활성이 유사한 경향으로 나타나, 메밀 추출물의 산화스트레스 예방 및 치료 효과 가능성을 제시하였다.

• 한국식품저장유통학회지
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• 제12권2호
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• pp.141-145
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• 2005

RPC에서 도정수율은 물론이며 쌀의 품질과 직접 관계가 있는 도정도의 측정에 활용하기 위하여 3품종(추청, 남평, 오대)의 현미를 도정도 $0\~20\%$범위에서 도정하면서 측정한 백도를 이용하여 도정도별 비선형 백도모델을 개발하였으며, 이 때 결정계수는 0.990, RMSE는 0.877로서 실측치와 예측치는 잘 일치하여 개발된 백도모델은 적용이 가능한 것으로 판단되었다. 또한, 칼라간의 상관관계를 구명하기 위하여 Lab와 RGB 쌀의 칼라시스템의 칼라인자와 백도와의 상관관계를 검토한 결과, Lab 칼라체계에서 b값 및 Hunter whiteness와 RGB 칼라체계에서 B값이 각각 결정계수 0.990, 0.985, 0.989로서 백도와 높은 상관관계를 나타내었다. b값과 B값이 쌀의 노란색과 파란색정도를 나타내고 있어 쌀의 백도는 특히 노란색과 파란색의 정도로 나타낼 수 있음을 알 수 있었다.

• Journal of Biosystems Engineering
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• 제26권5호
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• pp.469-474
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• 2001

Milling the rice with low moisture requires more energy, produces more cracked rice, and results in reducing taste of cooked rice. Accordingly, it is necessary to add moisture to the rice with low moisture to obtain optimum moisture level for milling and taste of rice. This study was performed to evaluate the influence of initial moisture content and absorption rate on rice crack, milling energy and whiteness of milled rice and to obtain the information for design of rewetting system mounted on stirring device in grain bin. The tests were conducted for the four levels of initial moisture content in the range of 11.4 to 14.5%(w.b.) and six levels of absorption rate in the range of 0.04 to 1.0%, w.b./hr. In the case of lower moisture content below 12%(w.b.), crack ratios of brown rice were remarkably high regardless of initial moisture contents. Therefore, it was found that rough rice below 12%(w.b.) in initial moisture content could not rewetted by spraying water without crack generation of low level. Absorption rate must be below 0.3%, w.b./hr to maintain crack ratio increase of less than 1% regardless of initial moisture contents. In the case of allowable crack ratio increase of 2% and 5%, it was found that the maximum absorprion rate was respectively 0.6%, w.b./hr and 1.0%, w.b./hr in the initial moisture content of above 13.5%(w.b.). Rewetting the rough rice in moisture content of 11.4 to 14.5%(w.b.) to 14.3 to 16.9%(w.b.) decreased milling energy consumption by 15.9 to 22.3%. The effect of energy saving was higher in the samples of higher initial moisture content. Whiteness of milled rice was decreased by 0.5 to 1.5.

• 열처리공학회지
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• 제31권3호
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• pp.135-142
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• 2018

In this study, we have fabricated n-type $Bi_2Te_{2.85}Se_{0.15}$ compounds by different processing routes such as crushing, milling and mixing respectively. Subsequently, the obtained powders were consolidated by spark plasma sintering (SPS). The phase crystallinity of bulk samples were identified using X-ray diffraction technique. Powder morphology and fracture surface of bulk samples were observed using the scanning electron microscopy (SEM). The Seebeck coefficient and electrical conductivity values were significantly increased for the milling sample than crushing and mixing samples. As a result, the maximum power factor was obtained $2.4mW/mK^2$, which is thrice than that of crushing process. The maximum figure of merit (ZT) of 0.77 was achieved at 400 K for the milling sample. Furthermore, relatively high hardness and density values were noticed for the different processed samples.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2003년도 추계총회 및 연구발표회 초록집
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• pp.183.2-183
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• 2003

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 추계학술대회 논문집
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• pp.539-540
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• 2010