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        검색결과 34

        2.
        2021.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of this study was to evaluate the basic data of Cirsium setidens Nakai fine powder (FPC), which will then be used in the development of functional fooditems. We measures and evaluated the level of pectolinarin content, phenol content, flavonoids content, antioxidants and anti-obesity properties of FPC. Our results from the study showed that the pectolinarin, phenol, and flavonoids contents of FPC measured at 10.95±0.15 mg/g, 12.92±0.18 mg gallic acid equivalent (GAE)/g and 26.47±0.77 mg rutin equivalent (RE)/g, respectively. The exhibited antioxidant activity of FPC increased significantly depending on the dosage, and additionally. FPC did not show any cytotoxicity up to the dosage level of 500 μg/mL. During adipocyte differentiation, FPC significantly inhibited ROS production and lipid accumulation, compared with the control substance. These results suggest that FPC could be considered a promising resource of natural antioxidants and could serve a variety of health-improving roles in the production of functional food ingredients.
        4,000원
        3.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this work, ultra-fine calcium oxide (CaO) powder derived from eggshells is used as the starting material to synthesize mineral trioxide aggregate (MTA). The prepared CaO powder is confirmed to have an average particle size of 500 nm. MTAs are synthesized with three types of fine CaO-based powders, namely, tricalcium silicate (C3S), dicalcium silicate (C2S), and tricalcium aluminate (C3A). The synthesis behavior of C3S, C2S and C3A with ultra-fine CaO powder and the effects of C3A content and curing time on the properties of MTA are investigated. The characteristics of the synthesized MTA powders are examined by X-ray diffraction (XRD), field emission-scanning electron microscope (FE-SEM), and a universal testing machine (UTM). The microstructure and compressive strength characteristics of the synthesized MTA powders are strongly dependent on the C3A wt.% and curing time. Furthermore, MTA with 5 wt.% C3A is found to increase the compressive strength and shorten the curing time.
        4,000원
        4.
        2013.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Ultra-fine zirconium carbide (ZrC) powder with nano-sized primary particles was synthesized by the carbothermal reduction method by using nano-sized and nano-sized graphite powders mixture. The synthesized ZrC powder was well dispersed after simple milling process. After heat-treatment at for 2 h under vacuum, ultra-fine ZrC powder agglomerates (average size, ) were facilely obtained with rounded particle shape and particle size of ~200 nm. Ultra-fine ZrC powder with an average particle size of 316 nm was obtained after ball milling process in a planetary mill for 30 minutes from the agglomerated ZrC powder.
        4,000원
        7.
        2006.09 구독 인증기관·개인회원 무료
        In recent years, PCB drills with smaller diameters less than 0.1 mm are used and thus there are growing needs for ultra-fine grained cemented carbides. However, ultra-fine WC powder usually causes extraordinary grain growth during sintering which weakens mechanical strength of ultra-fine grained cemented carbides. So we examined several kinds of WC powders to make new ultra-fine grained cemented carbides having superior performance. We found that direct carburized WC powder is very good as a WC raw material. The PCB drills made of the developed ultra-fine grained cemented carbides have higher hardness, toughness and stiffness than conventional ones.
        8.
        2006.09 구독 인증기관·개인회원 무료
        A new extra-fine grade Ni powder (XF Ni) has demonstrated increased sintering activity in Co-Fe-Ni binders for diamond tool applications. XF Ni has the advantage of significantly lower cost than XF Co. Up to 30% of XF Co was substituted with XF Ni while maintaining comparable apparent hardness and transverse rupture strength to pure Co binders. Ni substantially increased the diffusion of Fe. Diamond tool producers can take advantage of the improved sintering properties of XF Ni powder to substantially lower material costs.
        9.
        2006.09 구독 인증기관·개인회원 무료
        The MIM industry is currently focusing on parts that are used in automobiles and medical instruments. Many of the parts in these categories are very small and often not easy to machine because of its complex geometry. Therefore MIM is well suited for the production of these parts. We tested the sinterability of SUS316L ultra fine powders (3,4, 6, 8micron) produced by ATMIX high-pressure water-atomization, and it showed excellent results. A density of 97% theoretical was obtained by sintering at 1373K when using the ultra fine powder (3micron). Specifically, the finer the powder size, higher was the sintered density. The surface roughness and accuracy are also greatly improved with ATMIX ultra fine powder.
        10.
        2006.09 구독 인증기관·개인회원 무료
        Granulated powders, prepared from PF-5F(D50=4μm), PF-10F(D50=6μm) and PF-20F(D50=10μm) water atomized powder, were compacted, debound and sintered to evaluate the properties of sintered parts. As a result, the relative sintered density of about 97% at sintering temperature of 1423K was obtained. It can be considered that by using granulated finer particle size powder, mechanical properties of sintered parts were also improved.
        11.
        2006.04 구독 인증기관·개인회원 무료
        Development of recycling method at cemented carbide scraps was researched. Some properties of recycled cemented carbides were investigated. Recycled WC fine powder suffered the surface oxidation. Therefore it was necessary to be done by reduction treatment at 1073K-3.6ks under hydrogen atmosphere. When sintering condition at 1673K-3.6ks was treated under vacuum condition, it gained the deflective strength of about 90%, and gained hardness and sintering density about same value compared with commercial alloys. As a result, it was able to recycle only by 7 processes.
        12.
        2006.04 구독 인증기관·개인회원 무료
        Flying trajectories of fine particles within a size range of were studied during centrifugal atomizing processes. A FORTRAN program was written by using increment method. Calculation results revealed that the drag force might reach very high value of 522-7800 g for fine powder of . Flying distance in horizontal direction could be shortened if the particles fly obliquely due to the huge drug force. On the other hand, very fine powder could be projected to far distances when the atmosphere flow velocity is much stronger. Fortunately such particles could be contracted within a cylinder closed to the atomizer when the atmosphere flow was weaken or retained in a limited diameter.
        13.
        2006.04 구독 인증기관·개인회원 무료
        High-Speed Centrifugal Compaction Process is one of slip-using compacting method originally developed for processing of oxide ceramics. In this study, we apply the HCP to ultra-fine (0.1 micron) WC powder. Organic liquid of heptane was chosen as dispersing media to avoid possible oxidation of WC. The mixing apparatus was a key to obtain dense compacts. Only the slips mixed by high energy planetary ball mill were packed up to 55% by the HCP, and sintered to almost full density at 1673 K without any sintering aids. This sintered compact marked Vickers hardness of Hv 2750 at maximum.
        14.
        2006.04 구독 인증기관·개인회원 무료
        Hybrid atomization is a new atomization technique that combines gas atomization with centrifugal atomization. This process can produce fine, spherical powders economically with a mean size of about 10 m diameter and a tight size distribution.
        15.
        2005.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 식생활의 향상 및 건강식품에 대한 관심을 반영하여 2%의 저염도 통배추 김치에 미삼추출분말을 단독 또는 미삼추출물과 오미자즙을 병용하여 첨가하였다. 김치는 25℃에서 24시간 발효 한 뒤, 4℃에서 40일간 저장하며 5일마다 김치의 이화학적, 미생물학적 특성과 함께 관능적 특성을 조사하여 상관관계를 분석하였다. pH와 환원당은 저장 초기에는 미삼추출분말 및 오미자즙 첨가군이 유의적으로 가장 높게 나타났지만, 저장 11일부터는 미삼추출분말 첨가군이 가장 높게 나타났다. 산도와 용존 CO2 함량은 저장기간 내내 전반적으로 미삼추출분말 및 오미자즙 첨가군이 가장 높게 나타났으며, 용존 CO2 함량은 미삼추출분말 및 오미자즙 첨가군, 미삼추출분말 첨가군, 대조군의 순서로 유의적으로 높게 나타났다. 경도는 저장기간 내내 미삼추출분말 첨가군이 유의적으로 가장 단단하게 나타났다. 미생물 중 총균수 및 젖산균수는 저장 6일부터 미삼추출분말 및 오미자즙 첨가군이 가장 많이 나타났다. 관능특성검사 결과, 미삼추출분말 첨가군은 신맛이 약하고, 경도가 단단하게 평가되어 대조군에 비해 저장성이 증가되었음을 알 수 있었다. 미삼추출분말 및 오미자즙 첨가군은 미삼추출 분말 첨가군과 인삼향미는 유의적인 차이가 없으며, 쓴맛은 유의적으로 약하게 평가되어 소비자 검사 결과 대조군과 유의적인 차이 없이 미삼추출분말 첨가군보다 높게 평가되었다. 이화학적 특성과 관능검사의 특성검사의 상관관계는, 용출된 국물양은 산도와 양의 상관관계, pH 및 경도와 음의 상관관계가 있었고, 용존 CO2함량과 용출된 국물양은 양의 상관관계가 있었다. 탄산미는 신맛과 매우 높은 양의 상관관계가 있었으며, 경도 및 아삭거림과 음의 상관관계가 있었다. 신맛과 탄산미는 pH와 음의 상관관계, 산도와 양의 상관관계가 있었다. 이상의 결과로 저염도 배추김치에 미삼추출분말과 오미자즙을 첨가함으로써 기능성 증진과 더불어, 인삼의 쓴맛을 완화시켜 기호도를 상승시키는 효과가 있었다. 그러나 미삼추출분말 첨가군의 저장성이 향상되었던 것과는 달리 미삼추출분말과 오미자즙을 함께 넣은 처리구에서는 대조군과 비슷한 발효 양상을 보이는 결과가 나타났는데 이는 미삼과 오미자즙의 상호작용에 의한 결과라고 생각되며, 이에 관한 더 많은 연구가 필요하다고 생각한다.
        4,000원
        17.
        2005.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper deals with the fabrication of titanium carbide using fine titanium hydride. The ratio of and C (Activated carbon) was 1:1 (mol) and milled in a planetary ball mill at a ball-to-powder weight ratio of 20:1. Thereafter, TGA was performed at to observe change of weight with milling time. Titanium carbide was obtained by using tempering the milled powders at . The microstructures of titanium carbide as well as the change of the lattice parameters and particle size have been studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM).
        4,000원
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