• 한국결정성장학회지
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• 제25권3호
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• pp.93-97
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• 2015

본 연구에서는 고순도 균질 마이크로 Ag 입자를 얻기 위하여 용매추출법과 RF-LPP법을 이용하여 Air 분위기에서 $500^{\circ}C$에서 3시간 동안 열처리하여 Ag 입자를 합성하였다. 합성된 마이크로 Ag 입자를 XRD에 의해 비교 분석한 결과 주요 peak들이 JCPDS card(No. 87-0719)와 일치하는 것을 확인하였다. RF-LPP법을 이용함으로써, 핵 생성 싸이트 제어를 통해 균질 마이크로 Ag 입자를 합성하였으며, 환원처리 후 산소의 함유가 줄어드는 것을 확인하였다. 본 연구를 통하여 재활용 기술에 큰 기여를 할 것이라 기대한다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.1293-1296
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• 2009

The synthesis of nano-size ($Y_{0.955}Eu_{0.1}$)($P_{0.7}V_{0.45}$)$O_4$ red phosphors were conducted by using a Liquid Phase Precursor (LPP) method. In this method, cellulose pulp was used as a template showing the micro fibre structures to obtain the nano size YPV red phosphor. Aqueous solutions of raw materials were impregnated into cellulose pulp and subsequently impregnated pulp was dried and fired at $800-1200^{\circ}C$ for 1h. The effect of luminescence properties on compositions and temperatures was evaluated with photoluminescence spectrum, X-ray diffraction and FE-SEM, and TEM. High efficiency (~110%) of phosphor of size of ~500nm fired at $1150^{\circ}C$ was obtained compared with the micro size of commercial product. High efficiency behaviors of nano size phosphors were discussed in this paper.

• 한국해양공학회지
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• 제24권6호
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• pp.86-91
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• 2010

Superconductor material $Bi_2Sr_2Ca_2Cu_3O_x$(Bi-2223) powders were synthesized by ultrasonic spray pyrolysis method. It is clear that Bi-2223 phase more than Bi-2212 phase was acquired at sufficient synthesized time. Best condition for Bi-2223 phase was synthesizing temperature at $860^{\circ}C$. We also investigated the effects for concentrations and viscosities of starting liquid precursor as well as temperature distribution of reacting furnace. The size of synthesized powder was decreased by decreasing the concentration of starting liquid precursor. Modified reacting furnace with four different temperature heating zones gave us successful results for desirable nano-powder including $Bi_2Sr_2Ca_2Cu_3O_x$ phase. Citric acid addition to starting liquid precursor showed increasing of the size for synthesized powder. Bi-2223 single phase was acquired from Bi2223 and Bi-2212 mixed phases through heat treatment in box furnace at 24 hours.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.69-72
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• 1999

A Well oriented Bi$_2$re$_2$CaCu$_2$O$\sub$8/(Bi2212) superconductor thick films were formed successfully on a copper substrate by liquid reaction between a Cu-free precursor and Cu tape using method in which Cu-free BSCO powder mixture was printed on copper plate and heat-treated. And we examined the mechanism for the rapid formation of Bi2212 superconducting films from observing the surface microstructure with heat-treatment time. At heat-treatment temperature, the printing layer partially melt by reacting with CuO of the oxidizing copper plate, and the nonsuperconducting phases present in the melt are typically Bi-free phases and Cu-free phases. Following the partial melting, the Bi$_2$Sr$_2$CaCu$_2$O$\sub$8/ superconducting phase is formed at Bi-free phase/liquid interface by nucleation and grows. It was confirmed that the phase colony from the phase diagram of Bi$_2$O$_3$-(SrO+CaO)/2-CuO system is similar to the observed result.

• 문화기술의 융합
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• 제9권3호
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• pp.593-599
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• 2023

질산니켈육수화물염(nickel(II) nitrate hexahydrate) 수용액을 공업용 펄프에 함침시킨 전구체를 이용하여 세라믹스 분말을 제조하는 간단한 액상 합성법으로 산화니켈(NiO) 나노입자를 성공적으로 합성하였다. 질산니켈육수화물염 수용액이 함침된 전구체의 미세구조를 주사전자현미경(SEM)으로 확인하였고, 전구체의 열처리온도 증가에 따라 생성되는 산화니켈(NiO) 입자의 결정구조 및 입자크기를 X선회절분석(XRD) 및 SEM으로 분석하였다. 그 결과 전구체의 유기물질이 완전하게 열분해 되는 온도는 495-500℃이며, 열처리 온도의 증가에 따라 생성되는 산화니켈 입자의 크기 및 결정성이 증가하는 것을 XRD, SEM 분석을 통하여 확인하였다. 500-800℃에서 각각 1시간 동안 열처리하여 얻어진 산화니켈 입자의 크기는 50-200nm였다. 열처리 온도 380℃에서 NiO 결정상이 형성되고, 800℃까지는 NiO 단일상만 존재하며, 열처리 온도가 높아짐에 따라 생성되는 입자의 크기가 커지고 있음을 XRD 및 SEM 분석으로 확인하였다.

• 문화기술의 융합
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• 제9권6호
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• pp.855-859
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• 2023

질산구리삼수화물염(copper(II) nitrate trihydrate) 수용액을 공업용 전분(starch)에 함침 시킨 전구체를 이용하여 산화구리(CuO) 나노 입자를 합성하였다. 주사전자현미경(SEM)을 통하여 질산구리삼수화물염 수용액이 함침된 전구체에 대한 구조를 분석하였고, 전구체에 대한 열처리 온도를 증가 시킴에 따라 생성되는 산화구리 입자의 입자 크기와 결정 구조를 X선회절분석법(XRD)과 주사전자현미경(SEM)으로 분석하였다. 분석 결과에 따르면, 전구체에서 유기물질이 완전히 열분해 되어지는 온도는 450-490℃이며, 열처리하는 온도가 증가함에 따라 생성되는 산화구리 입자의 크기와 결정성이 증가하는 것을 확인할 수 있었고, 또한 500-800℃에서 1시간씩 열처리하여 얻은 산화구리 입자의 크기는 100nm-2㎛인 것으로 나타났다. 하소 온도 400℃에서 산화구리 결정상이 형성되고, 800℃까지는 산화구리 단일상만 존재하며, 하소 온도의 증가에 따라 생성되는 입자의 크기가 커지는 것을 확인하였다.

• 한국분말재료학회지
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• 제18권4호
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• pp.332-339
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• 2011

Cemented tungsten carbide has been used in cutting tools and die materials, and is an important industrial material. When the particle size is reduced to ultrafine, the hardness and other mechanical properties are improved remarkably. Ultrafine cemented carbide with high toughness and hardness is now widely used. The objective of this study is synthesis of nanostructured WC-Co powders by liquid phase method of tungstate. The precursor powders were obtained by freezen-drying of aqueous solution of soluble salts, such as ammonium metatungstate, cobalt nitrate. the final compositions were WC-10Co. In the case of liquid phase method, it can be observed synthesis of WC-10Co. The properties of powder produced at various temperature, were estimated from the SEM, BET and C/S analyser.

• Bulletin of the Korean Chemical Society
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• 제23권9호
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• pp.1304-1323
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• 2002

Superconducting BiSrCaCu(Ni)O ceramicss have been prepared by the gel method using an aqueous solution containing a tartaric acid. The aqueous solution of metal salts was concentrated without precipitation. The precursor so prepared was homogeneou s and calcined at $825^{\circ}C$ for 24 h to produce superconducting phase. The thermal decomposition of gels, the formation of superconducting phase, and their ceramic microstructure were studied using IR, TGA, XRD, resistance measurements, and SEM. This method is highly reproducible and leads to powders with excellent homogeneity and small particle size for easy sinterability. The nickel dopant substituting for Cu gives rise to the gradual decrease of the Tc. Phase pure 2212 ceramics were obtained at 825 $^{\circ}C$ for 24 h. SEM pictures showed that liquid phase was formed when the samples were sintered temperatures higher than 825 $^{\circ}C$.

• Bulletin of the Korean Chemical Society
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• 제25권1호
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• pp.109-114
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• 2004

A sensitive method for quantitation of glimepiride in human plasma has been established using liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI/MS/MS). Glipizide was used as an internal standard. Glimepiride and internal standard in plasma sample was extracted using diethyl etherethyl acetate (1 : 1). A centrifuged upper layer was then evaporated and reconstituted with the mobile phase of acetonitrile-5 mM ammonium acetate (60:40, pH 3.0). The reconstituted samples were injected into a $C_{18}$ reversed-phase column. Using MS/MS in the multiple reaction monitoring (MRM) mode, glimepiride and glipizide were detected without severe interference from human plasma matrix. Glimepiride produced a protonated precursor ion ([M+H]$^+$) at m/z 491 and a corresponding product ion at m/z 352. And the internal standard produced a protonated precursor ion ([M+H]]$^+$) at m/z 446 and a corresponding product ion at m/z 321. Detection of glimepiride in human plasma by the LC-ESI/MS/MS method was accurate and precise with a quantitation limit of 0.1 ng/mL. The validation, reproducibility, stability, and recovery of the method were evaluated. The method has been successfully applied to pharmacokinetic studies of glimepiride in human plasma.

• Advances in nano research
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• 제14권1호
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• pp.103-115
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• 2023

Recent developments in the synthesis of nanomagnesia of controlled sizes and shapes that are suitable for various applications are reviewed. Two main methods, based on liquid-phase synthesis, i.e., chemical methods and bio-based methods, are used to synthesize nanomagnesia. Conventionally, nanomagnesia was synthesized by chemical methods such as coprecipitation, sol-gel, combustion method, and so on using different chemical agents and stabilizers which later on become responsible for several biological risks because of the toxicity of used chemicals. Bio-based protocols are growing as another environmental friend method for the synthesis of various nanostructures especially nanomagnesia using biomass, plant extracts, alga, and fungi as a source of precursor material. The ideal method should offer better control of textural properties of nanostructures and decrease the necessity for purification of the synthesized nanoproducts, which sequentially removes the use of large amounts of chemicals and organic solvents and manipulation of products that are unsafe to the environment. Finally, the broad applicability of nanomagnesia in diverse areas is presented. Employment of nanomagnesia reported in several laboratory and industrial fields are valued from the standpoint of the significance of these issues for technological requests, as described in the literature. Nanomagnesia has various applications such as antimicrobial performance, removing pollutants, batteries application, and catalysis.