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        검색결과 335

        81.
        2017.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Synthesized monocrystalline nanodiamond (nD) particles are heat-treated at various temperatures to produce highly structured diamond crystals. The heat-treated nDs show different weight loss ratios during thermogravimetric analysis. The crystallinities of the heat-treated nDs are analyzed using Raman spectroscopy. The average particle sizes of the heat-treated nDs are measured by a dynamic light scattering (DLS) system and direct imaging observation methods. Moreover, individual dispersion behaviors of the heat-treated nD particles are investigated based on ultrasonic dispersion methods. The average particle sizes of the dispersed nDs according to the two different measurement methods show very similar size distributions. Thus, it is possible to produce highly crystallized nD powder particles by a heattreatment process, and the nD particles are relatively easy to disperse individually without any dispersant. The heattreated nDs can lead to potential applications such as in nanocomposites, quantum dots, and biomedical materials.
        4,000원
        82.
        2017.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Mill scale, an iron waste, was used to separate magnetite particles for the adsorption of phosphate from aqueous solution. Mill scale has a layered structure composed of wustite (FeO), magnetite (Fe3O4), and hematite (Fe2O3). Because magnetite shows the highest magnetic property among these iron oxides, it can be easily separated from the crushed mill scale particles. Several techniques were employed to characterize the separated particles. Mill scale-derived magnetite particles exhibited a strong uptake affinity to phosphate in a wide pH range of 3-7, with the maximum adsorptive removal of 100%, at the dosage of 1 g/L, pH 3-5. Langmuir isotherm model well described the equilibrium data, exhibiting maximum adsorption capacities for phosphate up to 4.95 and 8.79 mg/g at 298 and 308 K, respectively. From continuous operation of the packed-bed column reactor operated with different EBCT (empty bed contact time) and adsorbent particle size, the breakthrough of phosphate started after 8-22 days of operation. After regeneration of the column reactor with 0.1N NaOH solution, 95-98% of adsorbed phosphate could be detached from the column reactor.
        4,000원
        83.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Bi2Te3 powders are recovered by wet chemical reduction for waste n-type thermoelectric chips, and the recovered particles with different morphologies are prepared using various surfactants such as cetyltrimethylammonium bromide (CTAB), sodium dodecylbenzenesulfonate (SDBS), and ethylenediaminetetraacetic acid (EDTA). When citric acid is added as the surfactant, the shape of the aggregated particles shows no distinctive features. On the other hand, rod-shaped particles are formed in the sample with CTAB, and sheet-like particles are synthesized with the addition of SDBS. Further, particles with a tripod shape are observed when EDTA is added as the surfactant. The growth mechanism of the particle shapes depending on the surfactant is investigated, with a focus on the nucleation and growth phenomena. These results help to elucidate the intrinsic formation mechanism of the rod, plate, and tripod structures of the Bi2Te3 recovered by the wet reduction process.
        4,000원
        84.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        With relevance theory and coherence theory as the theoretical basis, this paper studies the pragmatic function of Chinese-Utterance final particles: a, ba and ne and claims that the discourse function of ne is stronger than a and ba. In other words, the modality meaning of a and ba is stronger than ne. This paper also studies the reason why a, ba and ne have different pragmatic functions and concludes that the meaning of ne is mainly the meaning of mood, ne has a longer history and the grammaticalization of ne is more complete while a and ba have obvious modality meaning; they have a shorter history than ne as mood particles and their grammaticalization still continues.
        4,500원
        86.
        2017.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Various morphologies of copper oxide (CuO) have been considered to be of both fundamental and practical importance in the field of electronic materials. In this study, using Cu (0.1 μm and 7 μm) particles, flake-type CuO particles were grown via a wet oxidation method for 5min and 60min at 75 oC. Using the prepared CuO, AlN, and silicone base as reagents, thermal interface material (TIM) compounds were synthesized using a high speed paste mixer. The properties of the thermal compounds prepared using the CuO particles were observed by thermal conductivity and breakdown voltage measurement. Most importantly, the volume of thermal compounds created using CuO particles grown from 0.1 μm Cu particles increased by 192.5% and 125 % depending on the growth time. The composition of CuO was confirmed by X-ray diffraction (XRD) analysis; cross sections of the grown CuO particles were observed using focused ion beam (FIB), field emission scanning electron microscopy (FE-SEM), and energy dispersive analysis by X-ray (EDAX). In addition, the thermal compound dispersion of the Cu and Al elements were observed by X-ray elemental mapping.
        4,000원
        87.
        2016.12 구독 인증기관 무료, 개인회원 유료
        本稿ではCD-ROM版新潮文庫の100冊と佐賀新聞(2001年と2003年1 月~12月)から収集した資料をもとに複合格助詞にとってとに、とし てとの交替現象及びその成立条件について考察を行った。その結果、以 下のようなことが分かった。 Xにとって(は)、AはBだ文の特徵において [1] 意味上、Xの立場から想定した觀點では AはBであるという判斷が成立可能である。 [2] Xは、主に人や擬人化された組織を表すものである。 [3] B は不可能を表す表現や内的な感情․感覚を表す表現や価 値判断や評価を表す表現のような狀態性の高いものが多い。 [4] 對比的な文脈を必要とする場合が多い。
        6,400원
        88.
        2016.11 구독 인증기관·개인회원 무료
        본 연구에서는 유화중합을 이용하여 폴리스타이렌계 나노사이즈의 입자를 제조하였으며 이를 후술폰화 공정을 이용하여 술폰산기를 도입시킨 고분자 입자를 제조 하였으며, 이를 이용하여 술폰화된 PEEK내에 도입하여 복합막을 제조하였다. 도입된 입자의 경우 고분자 분리막 내에 고르게 분산이 되었으며 제조된 분리막의 경우 입자의 함량이 증가됨에 따라 향상된 이온교환 능력 및 프로톤 전도도를 나타냄으로써 연료전지용 젼해질 막으로써의 적용가능성을 확인할 수 있었다.
        89.
        2016.11 구독 인증기관·개인회원 무료
        본 연구에서는 최근 분리, 흡착과 같은 물리적인 수처리 공정이 중요해짐에 따라 Track-etched polycarbonate(PC) membrane이 친수성이며 균일한 기공크 기를 가지고 기계적 강도가 우수하다는 점을 이용하여 표면이 하전되어있는 입자를 포함한 콜로이드 용액의 제거능력에 대해 조사형 분리 특성을 파악하였다. 유화중합을 이용하여 각각 양전하, 음전하로 각각 하전된 균일하며 착색된 나노 입자(70 ~200nm)를 제조하고, SEM, DSC, FT-IR 및 제타 전위를 측정하여 라텍스의 특성을 파악하였다. 이후 PC membrane의 표면전하 및 기공크기와 입자의 표면전하 및 입자크기에 따른 수투과도 및 배제율을 조사하였다.
        90.
        2016.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 고순도의 모데나이트(Mordenite) 입자를 합성하기 위하여 천연 제올라이트를 시드로 사용하여 시 드의 농도 및 수열합성 시간에 따른 천연 제올라이트 시드가 합성에 미치는 영향을 고찰하였다. 그 결과 시드가 입자의 형성 에 큰 영향을 끼치는 것을 확인할 수 있었고 시드를 3 g/100 g batch 주입하여 140°C에서 72시간 동안 수열합성을 진행하였 을 때 1-2 μm 사이즈의 고순도 모데나이트 입자를 합성할 수 있었다. 이를 통해 모데나이트 입자의 성장 기구를 규명할 수 있었으며, 모데나이트 입자 형성에 있어 시드는 첫째, 구형 모데나이트 전구체 형성 자리 공급의 역할과, 둘째 모데나이트 원 료 물질 소스 역할을 한다는 것을 알 수 있었다. 합성된 모데나이트 입자의 가스 흡착량 분석 결과 CO2 기체의 흡착량이 97.19 mg/g로 다른 가스들에 비해 비교적 높은 흡착성능을 보였으며, CO2/H2의 선택도가 가장 우수한 것으로 나타났다. 따라 서 이러한 결과들을 바탕으로 용도에 맞는 고순도 상의 모데나이트 입자를 합성할 수 있음을 확인하였고 보다 낮은 가격으로 우수한 분리성능을 갖는 분리막 소재개발에 활용할 수 있을 것이라 판단된다.
        4,000원
        91.
        2016.10 구독 인증기관·개인회원 무료
        Canine parvovirus (CPV), a member of the genus Parvovirus, family Parvoviridae, is a significant causative agent in Canine reproductive failure, causing serious economic losses in the pet industry. The major capsid protein, VP2 is the main target protein for neutralizing antibodies in CPV. When VP2 was expressed using baculovirus, it was produced abundantly and assembled into virus-like particles (VLPs) similar in size and morphology to the original virions. It was named as CPV-VLP. Additionally, p35 sequences of canine distemper virus (CDV) as T-helper epitope were fusion-expressed with each of N-term, C-term or both sides of CPV-VP2. Production of double antigenic recombinant protein and formation of VLPs were analyzed by SDS-PAGE and transmission electron microscopy, respectively.
        92.
        2016.10 구독 인증기관·개인회원 무료
        Ginsenosides are sensitive to various factors such as pH, temperature, ionic strength, etc. However, powdery form of ginseng is good to preserve ginsenosides in it compared to the extracted form. In addition, the ginseng powder can provide pickering effect to control emulsion stability as a substitute of emulsifier forming wall on the surface of oil. A ginseng pickering emulsions was prepared by mixing, MCT oil, polysorbate 80 and ginseng. Thereafter, to homogenize the emulsions magnetic stirrer, homogenizer and ultra sonicator were used. The physicochemical properties, stability, and bioaccessibility of the ginseng pickering emulsion were investigated. Both particle size and polydisperse index of the ginseng pickering emulsion were constant as time elapsed. However, pH and zeta-potential of the ginseng pickering emulsion decreased over time. Moreover, to find out the proper amount of ginseng powder, different ginseng powder weights were added to sample respectively and the physiochemical characteristics were measured. The pH and zeta-potential value tended to decrease following increase of amount of ginseng powder. This result is impacted to food quality and it could be used as a preliminary result in the development of food product.
        93.
        2016.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Magnetite particles were synthesized by co-precipitation of water-soluble 밀 스케일-derived precursor by various concentrations of (0.5, 0.67, 1, 2 N) NaOH and (0.6, 0.8, 1.2, 2.4 N) NH4OH. It is theoretically known that as the concentration of the alkaline additive used in iron oxide synthesis increases, the particle size distribution of that iron oxide decreases. This trend was observed in both kind of alkaline additive used, NaOH and NH4OH. In addition, the magnetite synthesized in NaOH showed a relatively smaller particle size distribution than magnetite synthesized in NH4OH. Crystalline phase of the synthesized magnetite were determined by X-ray diffraction spectroscopy(XRD). The particles were then used as an adsorbent for phosphate(P) removal. Phosphorus adsorption was found to be more efficient in NaOH-based synthesized magnetite than the NH4OH-based magnetite.
        4,000원
        94.
        2016.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Ag nanoparticles are extensively studied and utilized due to their excellent catalysis, antibiosis and optical properties. They can be easily synthesized by chemical reduction methods and it is possible to prepare particles of uniform size and high purity. These methods are divided into vapor methods and liquid phase reduction methods. In the present study, Ag particles are prepared and analyzed through two chemical reduction methods using solvents containing a silver nitrate precursor. When Ag ions are reduced using a reductant in the aqueous solution, it is possible to control the Ag particle size by controlling the formic acid ratio. In addition, in the Polyol process, Ag nanoparticles prepared at various temperatures and reaction time conditions have multiple twinned and anisotropic structures, and the particle size variation can be confirmed using field emissions scanning electron microscopy and by analyzing the UV-vis spectrum.
        4,000원
        95.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Well-dispersed Ag3VO4 nanoparticles @polyacrylonitrile (PAN) nanofibers were synthesized by an easily controlled, template-free method as a photo-catalyst for the degradation of methylene blue. Their structural, optical, and photocatalytic properties have been studied by X-ray diffraction, transmission electron microscopy, field-emission scanning electron microscopy equipped with rapid energy dispersive analysis of X-ray, photoluminescence, and ultraviolet–visible spectroscopy. The characterization procedures revealed that the obtained material is PAN nanofibers decorated by Ag3VO4 nanoparticles. Photocatalytic degradation of methylene blue investigated in an aqueous solution under irradiation showed 99% degradation of the dye within 75 min. Finally, the antibacterial performance of Ag3VO4 nanoparticles @PAN composite nanofibers was experimentally verified by the destruction of Escherichia coli. These results suggest that the developed inexpensive and functional nanomaterials can serve as a non-precious catalyst for environmental applications.
        4,000원
        96.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Phagocytosis is a primary and an essential step of host defense, and is triggered by the interaction of particles with specific receptor of macrophages. In this study, we investigated the effect of extracts of Rudbeckia laciniata (RLE) on the phagocytic activity of macrophage, by monitoring the phagocytosis-associated signal transduction. RLE markedly increased phagocytosis of serum-opsonized zymosan particles (SOZ), while phagocytosis of IgG-opsonized zymosan particles (IOZ) or none-opsonized zymosan particles (NOZ) remained unaffected. However, RLE did not affect the binding of opsonized zymosan particles (OZ) with the cell surface of macrophage. This suggests that RLE may regulate SOZ-induced intracellular signaling during phagocytosis of macrophage. To confirm this hypothesis, we investigated whether RLE was involved in the RhoA-mediated signal transduction during phagocytosis of SOZ. Inhibitors of the RhoA-mediated signaling pathway, such as Y-27632 (for ROCK), ML-7 (for MLCK), and Tat-C3 (for RhoA), totally blocked phagocytosis of SOZ enhanced by RLE, as well as phagocytosis of SOZ. Additionally, RhoA activity was markedly increased when cells were treated with RLE, suggesting that RLE could increase the phagocytic activity of macrophage via RhoA-ROCK/MLCK signal pathway. Thus, RLE may be used to develop functional foods for immunity.
        4,000원
        97.
        2016.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this study, an environment-friendly synthetic strategy to process zinc oxide nanocrystals is reported. The biosynthesis method used in this study is simple and cost-effective, with reduced solvent waste via the use of fruit peel extract as a natural ligation agent. The formation of ZnO nanocrystals using a rambutan peel extract was observed in this study. Rambutan peels has the ability to ligate zinc ions as a natural ligation agent, resulting in ZnO nanochain formation due to the presence of an extended polyphenolic system over the whole incubation period. Via transmission electron microscopy, successful formation of zinc oxide nanochains was confirmed. TEM observation revealed that the bioinspired ZnO nanocrystals were spherical and/or hexagonal particles with sizes between 50 and 100 nm.
        4,000원
        98.
        2016.05 구독 인증기관·개인회원 무료
        본 연구에서는 고순도의 모데나이트 입자를 합성하기 위하여 천연 제올라이트를 시드로 사용하여 시드 농도 및 수열합성 시간에 따라 시드가 미치는 영향 을 고찰하였다. 시드를 3 g/100g batch 주입하여 140°C에서 72시간 동안 수열 합성 하였을 때 1-2 μm 사이즈의 고순도 모데나이트 입자를 안정적으로 합성할 수 있었다. 이를 통해 천연 제올라이트 시드는 모데나이트 입자의 성장에서 구형 모데나이트 전구체 형성 자리를 공급하고 모데나이트 원료 물질 소스 역 할을 한다는 것을 알 수 있었다. 이러한 결과들을 바탕으로 용도에 맞는 고순도 의 모데나이트 입자를 합성할 수 있음을 확인하였고 천연제올라이트를 사용함으로써 낮은 가격으로 우수한 성능을 갖는 소재개발에 활용할 수 있을 것이라 판단된다.
        99.
        2016.05 구독 인증기관·개인회원 무료
        이번 연구에서는 기존의 이온교환 수지를 대체 할 수 있는 물질에 대한 연구를 진행하였다. 이에 대한 물질로는 유화중합을 통해 Styrene monomer를 활용한 Polystyrene particle을 제조하였다. 이온기가 도입된 입자의 경우 기존의 이온교환수지보다 표면적이 훨씬 크고, 입자 크기가 작아 좁은 분포를 나타내어 더 높은 이온 교환 용량을 나타냄을 확인 하였다. 단분산된 입자에 Sulfonation 반응을 통해 -SO3 -관능기를 도입하였으며 이외에도 -COO-, -PO3 -, -C6H4O- 등의 관능기를 도입함으로써 SEBS 고분자 분리막을 음전하로 높게 하전 시킬 수 있 었다. 입자를 제조하고 이에 따른 특성평가는 SEM, FT-IR, Zeta potential, IEC value등의 전기적 특성과 TGA, DSC 등의 열적 특성을 파악하였다.
        100.
        2016.05 구독 인증기관·개인회원 무료
        본 연구에서는 기존의 음이온 교환 수지를 대체하기 위한 물질로써 Emulsion polymerization을 통해 Polystyrene Latex입자를 제조하였다. 관능기를 도입한 입자를 활용하였을 때 기존의 이온교환 수지가 가지고 있는 특성보다 좁은 분 포도를 가지며 훨씬 높은 표면적을 나타낸다. 단분산된 나노크기의 입자에 Chloromethylation과 Amination 반응을 통해 -NH3 +, -NR3 +, -PR3 +, -SR2 + 등의 관능기를 도입함으로써 SEBS 고분자 분리막을 양전하로 높게 하전시킬 수 있다. 입자를 제조하고 SEM, FT-IR, Zeta potential, IEC value 등의 전기적 및 TGA, DSC등의 열적인 부분을 특성평가 진행하였다.
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