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Ni-B 분말의 기계적 합금화 과정에서 밀링시간에 따른 미세조직과 상변화 거동
김정근,이욱진,박성균,박익민,박용호,Kim, Jung-Geun,Lee, Wook-Jin,Park, Sung-Kyun,Park, Ik-Min,Park, Yong-Ho 한국분말야금학회 2011 한국분말재료학회지 (KPMI) Vol.18 No.6
In this study, the effect of milling time on the microstructure and phase transformation behaviors of Ni-12 wt.%B powders was investigated using vibratory ball milling process. X-ray diffraction patterns showed that the phase transformation of mixed Ni-B elemental powder occurred after 50 hours of milling, with a formation of nickel boride phases. Through the study of microstructures in mechanical alloying process, it was considered that ball milling strongly accelerates solid-state diffusions of the Ni and B atoms during mechanical alloying process. The results of X-ray photoelectron spectroscopy showed that most of B atoms in the powder were linked to Ni with a formation of nickel boride phases after 200 hours of milling. It was finally concluded that mechanical alloying using ball milling process is feasible to synthesize fine and uniform nickel boride powders.
분말야금법으로 제조한 A359/SiCp 복합재료의 미세조직 및 기계적 특성에 미치는 강화재의 분포와 크기의 영향
김정근 ( Jung Geun Kim ),방정일 ( Jeong Il Bang ),김용진 ( Yong Jin Kim ),박용호 ( Yong Ho Park ) 대한금속재료학회(구 대한금속학회) 2013 대한금속·재료학회지 Vol.51 No.12
Abstract: The aim of this study is to characterize the microstructure and mechanical properties of aluminum metal matrix composites (MMCs) containing 20 vol% of silicon carbide particles (SiCp) with different particle sizes. The A359/SiCp MMCs sinterted specimens were respectively manufactured from a blended powder and composite powders by a hot press technique. The consolidated composite with the blended powder exhibited a clustered region of reinforcement particles in the matrix, which was due to the influence of the interfacial debonding of the SiCp/matrix during fracture. On the other hand, a homogeneous particle distribution of the composite powders and the SiCp was observed in the sintered specimens after fracture. Homogeneous distribution of the MMCs and SiCp was significantly affected by the method of the preparation or the powder materials. This phenomena was predominant elevation of the mechanical properties in these composites.
투라노스 당침을 통해 제조된 매실청의 저장기간 중 성분 함량 변화
김정근(Jung-Geun Kim),유상호(Sang-Ho Yoo) 한국식품과학회 2021 한국식품과학회지 Vol.53 No.6
본 연구는 설탕과 투라노스를 이용한 매실청의 주요 유리당과 유기산, 아미그달린의 함량 및 항산화 활성을 측정하여 설탕 대체 감미료로써 이용된 투라노스의 건강기능식품원료로의 가능성을 확인하고자 하였으며, 이에 따른 건강기능성 투라노스 매실청 제품 개발의 기초자료를 제공하고자 하였다. 매실과 첨가당의 비율을 1:1로 하여 제조한 설탕 및 투라노스 매실청을 저장일 15, 20, 25, 30, 40, 60, 90일에서 각각 취하였다. 저장기간동안 설탕 및 투라노스 매실청의 pH는 각 2.83-2.92, 2.87-3.00의 범위를 보였으며 당도는 54.55-57.30, 55.40-58.60°Bx로 관찰되었고, 두 당류로 제조된 매실청 모두 pH 및 당도의 변화는 저장 기간에 따라 유의적으로 관찰되지 않았다. 저장 기간 동안 설탕 매실청의 유리당은 저장 기간과 반비례하게 sucrose의 함량은 점차 감소하여 최종적으로 11% (w/w) 잔존하였고, glucose와 fructose는 저장기간과 비례하게 증가하는 경향을 보였으며 최종적으로 각각 25와 26% (w/w) 잔존하는 것으로 관찰되었다. 설탕 및 투라노스 매실청에서의 유기산 함량 분석에서 oxalic acid, malic acid 및 citric acid가 관찰되었으며 두 매실청 모두 citric acid가 가장 높은 함량을 차지하고 있었다. 설탕 매실청(SM)은 매실 과육으로부터 침출된 유기산에 의해 sucrose가 가수분해되어 glucose와 fructose함량이 증가하는 경향을 나타내는 반면, 투라노스 매실청(TM)에서 투라노스는 저장 전 기간 동안 구성당으로의 가수분해가 일어나지 않아 glucose와 fructose는 검출되지 않았으며, 저장기간 초기에는 매실 과육 속의 수분 침출로 인한 희석 효과로 인해 투라노스 함량이 소량 감소하는 경향을 보이며 저장 중기 이후에는 변화를 보이지 않았다. 따라서, 투라노스 매실청 섭취 시 설탕 섭취로 인한 혈당 증가로 인해 발생할 수 있는 질병을 예방할 수 있을 것으로 판단된다. 독성을 나타낼 수 있는 매실청 유래 아미그달린 함량의 경우 저장 기간이 증가할수록 두 가지 당류를 사용한 매실청 모두 증가하는 양상을 보여주었으나 설탕 매실청(SM)보다 투라노스 매실청(TM)에서 저장 전 기간 동안 상대적으로 낮게 측정되었으며, 설탕 및 투라노스 매실청에서 최종적으로 검출된 아미그달린 함량은 각각 167.76과 124.72 ppm으로 반수치사량(LD<SUB>50</SUB>)보다 낮은 농도로 확인되어 독성에 대한 위험수준은 매우 낮다고 볼 수 있다. 또한 두 매실청 모두 저장 기간에 따라 항산화능이 증가하는 경향을 나타냄으로써 체내 활성 산소 발생을 억제하는 효과를 기대할 수 있으며, 매실청 제조 시 설탕 대체 당류로 투라노스를 이용하면 건강기능성을 갖춘 식품으로써 제품 개발 가능성이 높을 것으로 판단된다. Turanose is a potential candidate for use as a functional sweetener because of its gentle taste, low calorie, and non-cariogenicity. The aim of this study was to replace sucrose with turanose to produce health-beneficial maesil-cheong. Quality effects of turanose on maesil-cheong were evaluated by determining the contents of free sugars, organic acids, amygdalin, and antioxidant activity. The pH and Brix values of sucrose- and turanose-based maesil-cheong remained at the same level between 2.83 and 3.00 and 54.6-58.6oBx, respectively, after 90-day storage. Among oxalic, malic, and citric acids, citric acid content was the highest in both maesil-cheong samples. Turanose did not significantly hydrolyze in maesil-cheong, whereas sucrose was completely hydrolyzed to glucose and fructose. Thus, turanose is suitable for the development of acidic maesil-cheong to improve its health promoting effect. Turanose showed product qualities similar to sucrose-based maesil-cheong. Turanose can be used as a functional sweetener or bulking agent in processed foods.
($Interferon-{\gamma}$)가 마우스 조골세포의 생물학적 활성에 미치는 영향에 관한 연구
이관훈,김정근,정진형,Lee, Kwan-Hoon,Kim, Jung-Geun,Chung, Chin-Hyung 대한치주과학회 1996 Journal of Periodontal & Implant Science Vol.26 No.1
Interferon(IFN) is a sort of glycoproteins that are produced by activated lymphocyte, monocyte and fibroblast. IFN has anti-viral effects, immuno-defensive mechanism and regulating properties to the several kinds of cells that includes affect on the bone formation and resorption. The effect of IFN on the osteoclast & other tissue cells has been studied in a number of researchers with the limited reports on the osteoblast. The purpose of this study was to evaluate the effects of IFN on the osteoblastic function. The MC3T3/El cell(Mouse osteoblast) was incubated in ${\alpha}-minimum$ essential medium containing 10% FBS. To detect the cytotoxic effect of $IFN-{\gamma}$ on osteoblast, the cells were cultured in 96-well plate to which $IFN-{\gamma}$ of various concentrations were added for 2 days. After staining with trypan blue, total cells and living cells were counted under microscope. To determine the activity of alkaline phosphataset(ALP), various concentrations of $IFN-{\gamma}$ were treated to culture medium, and biochemical assay was performed. $IFN-{\gamma}$ and $IFN-{\gamma}$ plus cycloheximide were added to culture medium separately and then ALP activity were determined. To detect the effect of the $IFN-{\gamma}$ on the bone formation of osteoblast, long-term culture was performed, and calcified nodule formation were observed using von Kossa's staining. After the addition of $IFN-{\gamma}$ with various concentrations to the medium, no cytotoxic effect of $IFN-{\gamma}$ was detected at any concentration. The significant increase in ALP activity of osteoblast were found the concentration of $IFN-{\gamma}$ 500-2500U/ml and the culture time of 24-48 hours respectively. The enhancement of ALP activity by $IFN-{\gamma}$ of osteoblast was decreased significantly by the treatment of cycloheximide. After long-term culture of osteoblast, the nodule formation was found to be increased in number and density by the addition of 500 U/ml $IFN-{\gamma}$. These results suggest that $IFN-{\gamma}$ was affected on the bone formation of osteoblast. Forthemore this kind of study or $IFN-{\gamma}$ to osteoblast will be held continuously.