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  • Title/Summary/Keyword: Spray method

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Optimization of VUV Characteristics of M3MgSi2O8:Eu2+ (M=Ca, Sr, Ba) Phosphor by Spray Pyrolysis (분무열분해법을 이용하여 M3MgSi2O8:Eu2+ (M=Ca, Sr, Ba) 형광체 분말의 VUV 특성 최적화)

  • Jung, You-Ri;Jung, Kyeong-Youl
    • Journal of Powder Materials
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    • v.15 no.5
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    • pp.399-404
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    • 2008
  • Spray pyrolysis was applied to prepare M3MgSi2O8:Eu2+ (M=Ca, Sr, Ba) blue phosphor powder. The library of a Ca-Sr-Ba ternary system was obtained by a combinatorial method combined with the spray pyrolysis in order to optimize the luminescent property under vacuum ultraviolet (VUV) excitation. 10 potential compositions were chosen from the first screening. The emission shifted to longer wavelength as Ca became a dominant element and the emission intensity was greatly reduced in the composition region at which Ba is dominant element. On the base of the first screening result, the second fine tuning was carried out in order to optimize the luminescence intensity under VUV excitation. The optimal composition for the highest luminescence intensity was (Ca1.7,Sr0.3,Ba1.0)Si2O8:Eu2+ which had the color coordinate of (0.152, 0.072) and about 64% emission intensity of BaMgAl10O17 (BAM) phosphor.

Efficiency enhancement of spray QD solar cells

  • Park, Dasom;Lee, Wonseok;Jang, Jinwoong;Yim, Sanggyu
    • Proceedings of the Korean Vacuum Society Conference
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    • 2016.02a
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    • pp.420.1-420.1
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    • 2016
  • Colloidal quantum dot (CQD) is emerging as a promising active material for next-generation solar cell applications because of its inexpensive and solution-processable characteristics as well as unique properties such as a tunable band-gap due to the quantum-size effect and multiple exciton generation. However, the most widely used spin-coating method for the formation of the quantum dot (QD) active layers is generally hard to be adopted for high productivity and large-area process. Instead, the spray-coating technique may potentially be utilized for high-throughput production of the CQD solar cells (CQDSCs) because it can be adapted to continuous process and large-area deposition on various substrates although the cell efficiency is still lower than that of the devices fabricated with spin-coating method. In this work, we observed that the subsequent treatment of two different ligands, halide ion and butanedithiol, on the lead sulfide (PbS) QD layer significantly enhanced the cell efficiency of the spray CQDSCs. The maximum power conversion efficiency was 5.3%, comparable to that of the spin-coating CQDSCs.

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A Study on the Fuel Behavior and Mixture Formation in the Early Injection Timing of GDI Injector (직분식 가솔린 인젝터의 흡입 행정 분사시의 연료 거동 및 혼합기 분포 특성에 관한 연구)

  • Lee, Chang-Hui;Lee, Gi-Hyeong;Bae, Jae-Il;Baek, Seung-Guk
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.26 no.8
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    • pp.1138-1144
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    • 2002
  • Recently GDI(Gasoline Direct Injection) engine is spot-lighted to achieve higher thermal efficiency under partial loads and better performance at full loads. To realize this system, it is essential to make both stratified combustion and homogeneous combustion. Spray pattern must be optimized according to injection timing because ambient pressure in combustion chamber is varied with crank angle. In this experimental study, two types of visualization system such as laser scattering method and schlieren method were developed to clarity the spray behavior during on intake stroke. As the ambient pressure increases, thepenetration length and spray angle show a tendancy to decrease due to rising resistance caused by the drag force of the ambient air. Distribution of injected fuel on intake stroke has a significant effect on homogeneous mixture in the cylinder. These results provide the information on macroscopic wall-wet growth in the cylinder and design factors for developing GDI injector.

Silk Fibroin Microsphere and Its Characterization

  • Yeo, Joo-Hong;Lee, Kwang-Gill;Lee, Yong-Woo;Kweon, Hae-Yong;Woo, Soon-Ok
    • International Journal of Industrial Entomology and Biomaterials
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    • v.6 no.2
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    • pp.151-155
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    • 2003
  • Using gel filtration chromatography, high molecular silk fibroin with high purity was obtained and silk flbroin microsphere particles (SFMP) could be simply made by spray dryer method. Also, some of the physicochemical properties of SFMP and morphology were investigated. The average molecular weight of pure silk fibroin protein dissolved in calcium chloride is about 61,500g/㏖ as measured by gel permeation chromatography. SFMP was spherical in shape, and particles, sized average of 2 ± 10 μ, were observed by SEM and particle analyzer, respectively. Obtaining microspheres particles by spray dryer method accelerated the transition from the random coil to the β-sheet structure during spray dryer treatment. It was identified by the basic fourier transform infrared spectroscopy of SFMP. The swelling ratio of SFMP is majorly dependent on the pH of the solution, not on the occurred gelation. The characteristic structure, which might be applicable to immobilization of drugs is superior to other matrix materials for the use of biomaterials with skin affinity.

Melting Point of Amorphous Copper Phase on Crystalline Silicon Solar Cells During Cold Spray using Molecular Dynamics Calculations (분자 동역학 계산을 통한 결정질 실리콘 태양전지 기판에 콜드 스프레이 전극 형성 시 발생되는 비정질 구리상에 대한 용융 온도 변화 연구)

  • Kim, Soo Min;Kang, Byungjun;Jeong, Sujeong;Kang, Yoonmook;Lee, Hae-seok;Kim, Donghwan
    • Current Photovoltaic Research
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    • v.3 no.2
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    • pp.61-64
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    • 2015
  • In solar industry, numerous researchers reported about cold spray method among various electrode formation technic, but there are no known a bonding mechanism of metal powder. In this study, a cross-section of copper electrode formed by cold spray method was observed and heterogeneous phase between silicon substrate and copper electrode was analyzed using morphology observation technic. SEM and TEM analysis were performed to analyze a crystallinity and distribution shape of heterogeneous copper phase. Molecular dynamics simulation was performed to calculate glass transition temperature of copper metal. In the result, amorphous copper phase was observed near interface between silicon substrate and metal electrode. The results of the molecular dynamics simulation show that an amorphous copper phase could be formed at a temperature below the melting point of copper because cold spraying resulted in a lower glass transition temperature.

Thermal Barrier Efficiency and Endurance of Ni-Cr Coating in Liquid Rocket Engine Combustor (액체로켓엔진 연소기에 적용된 니켈-크롬 코팅의 열차폐 효율과 내구성)

  • Lee, Kwang-Jin;Lim, Byoung-Jik;Kim, Jong-Gyu;Han, Yeoung-Min;Choi, Hwan-Seok
    • Aerospace Engineering and Technology
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    • v.8 no.1
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    • pp.138-143
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    • 2009
  • Thermal barrier efficiency and endurance of coatings in liquid rocket engine combustor were evaluated for air plasma spray coating and electro/electroless plating. The result of firing tests has revealed occasional occurrence of local delamination of ZrO2, NiCrAlY coating obtained by the method of air plasma spray in the region of supersonic flow and it necessitated a new coating method as a substitution. It was found that Ni-Cr coating by means of electro/electroless plating can substitute ZrO2, NiCrAlY coatings of air plasma spray in terms of thermal barrier efficiency and endurance.

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Optimization of Spray Drying Process for Manufacturing Dried Vinegar using Response surface methodology (분말식초제조를 위한 분무건조공정의 최적화)

  • 황성희;정용진;윤광섭
    • Food Science and Preservation
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    • v.9 no.2
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    • pp.194-199
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    • 2002
  • This study was conducted to develop processing method for vinegar powder from natural vinegar for encapsulation applications. To optimize the spray drying process, experiment was designed by central composition method to find optimal conditions for manufacturing vinegar powder. The acidity, water absorption, solid content and heat stability of vinegar powder were selected as response variables. The optimal concentration of inclusion complex which was made with vinegar and β-cyclodextrin was determined on 30。bx. On increasing the concentration of β-cyclodextrin as a wall material, the quality of the vinegar was decreased. The optimum conditions of spray drying process for manufacturing vinegar powder were 188∼192C and 500∼600 Lh\^ -1/ as inlet temperature and flow rate, respectively.

Development of Spray Coating Methods for Large Area Sol-Gel ZnO/Ag Nanowire Composite Transparent Conducting Substrates (대면적 졸-겔 산화아연/은 나노선 복합 투명 전도 기판 제조를 위한 스프레이 코팅법 개발)

  • Cho, Wonki;Baik, Seung Jae
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.31 no.1
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    • pp.55-60
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    • 2018
  • Transparent conductive thin films (TCFs) are essential materials for solar cells, organic light-emitting diodes, and display panels. Indium tin oxide (ITO) is one of the most widely used commercial materials to create TCFs'; however, new materials that can possibly replace ITO at a lower cost and/or those possessing mechanical flexibility are urgently needed. Silver nanowire (AgNW) is one of those promising materials, as it is less expensive and possesses superior mechanical flexibility as compared to ITO. We used AgNW and sol-gel ZnO to fabricate composite thin films by spray coating. We propose two spray-coating methods: the 'metal-organic chemical vapor deposition (MOCVD)/AgNW' method and the Mixture method. These two methods are expected to be commercialized for high-quality and low-cost products, respectively.

Optical Properties of Spherical YAG:Ce3+ Phosphor Powders Synthesized by Atmospheric Plasma Spraying Method Appling PVA Solution Route and Domestic Aluminium Oxide Seed (PVA 용액법과 국산 산화알루미늄을 적용하여 대기 플라즈마 용사법으로 합성된 구형의 YAG:Ce3+ 형광체의 발광특성)

  • Yong-Hyeon Kim;Sang-Jin Lee
    • Journal of Powder Materials
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    • v.30 no.5
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    • pp.424-430
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    • 2023
  • YAG phosphor powders were fabricated by the atmospheric plasma spraying method with the spray-dried spherical YAG precursor. The YAG precursor slurry for the spray drying process was prepared by the PVA solution chemical processing utilizing a domestic easy-sintered aluminum oxide (Al2O3) powder as a seed. The homogenous and viscous slurry resulted in dense granules, not hollow or porous particles. The synthesized phosphor powders demonstrated a stable YAG phase, and excellent fluorescence properties of approximately 115% compared with commercial YAG:Ce3+ powder. The microstructure of the phosphor powder had a perfect spherical shape and an average particle size of approx imately 30 ㎛. As a result of the PKG test of the YAG phosphor powder, the synthesized phosphor powders exhibited an outstanding luminous intensity, and a peak wavelength was observed at 531 nm.

Synthesis of Y2O3-Dispersed W Powders Prepared by Ultrasonic Spray Pyrolysis and Polymer Solution Route

  • Hyeonhui Jo;Young-In Lee;Myung-Jin Suk;Young-Keun Jeong ;Sung-Tag Oh
    • Archives of Metallurgy and Materials
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    • v.66 no.3
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    • pp.799-802
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    • 2021
  • The nano-sized Y2O3 dispersed W composite powder is prepared by ultrasonic spray pyrolysis of a tungsten precursor using ammonium metatungstate hydrate and a polymer addition solution method using Y-nitrate. XRD analysis for calcined powder showed the formation of WO2 phase by partial oxidation of W powder during calcination in air. The TEM and phase analysis for further hydrogen reduction of calcined powder mixture exhibited that the W powder with a uniform distribution of Y2O3 nanoparticles can be successfully produced. These results indicate that the wet chemical method combined with spray pyrolysis and polymer solution is a promising way to synthesis the W-based composites with homogeneous dispersion of fine oxide particles.