Strontium lanthanum vanadate La1-xSrxVO3 (LSVO) is a promising anode material for electrochemical devices, especially for solid oxide fuel cells, thanks to its irregular electrical conductivity. However, the known synthesis methods are incapable of producing well-dispersed LSVO nanoparticles (NPs) with homogeneous size distribution, which partly impedes the applicability of the material. Thus, a new approach to synthesize LSVO NPs with such characteristics is of paramount importance. In the present work, we successfully prepare LSVO NPs with a high dispersion degree and homogeneous size distribution via a modified co-precipitation pathway, followed by hydrogen reduction at a temperature as low as 700 oC. The prepared LSVO NPs display uniform sizes in the range of 50 ~ 100 nm and do not contain any secondary phases, according to XRD analysis. The chemical mechanism of reactions that occur to form the LSVO is thoroughly highlighted. The work functions of NPs measured by the UPS analysis are in the 2.13 ~ 3.62 eV range, making the LSVO powders promising for use in thermionic devices. An explanation of the role of Sr substitution in work function values of LSVO is also proposed.

In this study, (GaN)1-x(ZnO)x solid solution nanoparticles with a high zinc content are prepared by ultrasonic spray pyrolysis and subsequent nitridation. The structure and morphology of the samples are investigated by X-ray diffraction (XRD), field-emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The characterization results show a phase transition from the Zn and Ga-based oxides (ZnO or ZnGa2O4) to a (GaN)1-x (ZnO)x solid solution under an NH3 atmosphere. The effect of the precursor solution concentration and nitridation temperature on the final products are systematically investigated to obtain (GaN)1-x(ZnO)x nanoparticles with a high Zn concentration. It is confirmed that the powder synthesized from the solution in which the ratio of Zn and Ga was set to 0.8:0.2, as the initial precursor composition was composed of about 0.8-mole fraction of Zn, similar to the initially set one, through nitriding treatment at 700oC. Besides, the synthesized nanoparticles exhibited the typical XRD pattern of (GaN)1-x(ZnO)x, and a strong absorption of visible light with a bandgap energy of approximately 2.78 eV, confirming their potential use as a hydrogen production photocatalyst.

Nickel nanopowders are obtained by the spark discharge method, which is based on the evaporation of the electrode surface under the action of the discharge current, followed by vapor condensation and the formation of nanoparticles. Nickel electrodes with a purity of 99.99% are used to synthesize the nickel nanoparticles in the setup. Nitrogen is used as the carrier gas with a purity of 99.998%. XRD, TEM, and EDX analyses of the nanopowders are performed. Moreover, HRTEM images with measured interplanar spacings are obtained. In the nickel nanopowder samples, a phase of approximately 90 wt% with an expanded crystal lattice of 6.5% on average is found. The results indicate an unusual process of nickel nanoparticle formation when the spark discharge method is employed.

탄소 양자점 (CQDs, Carbon Quantum Dots)은 크기에 따라 광 물리적 특성이 다르게 나타나는 소재로 각광을 받고 있지만 용매의 호환성과 화학적 안정성은 개선해야 할 문제로 남아있다. 따라서 CQDs에 여러 소수성 기능기를 도 입하여 고분자 미셀 내부에 들어갈 수 있도록 표면을 개질하였다. 탄소 양자점이 함유된 고분자 미셀의 광 물리적 특성은 흡광, 형광 분광법으로 측정하였다.

Many electronic applications require magnetic materials with high permeability and frequency properties. We improve the magnetic permeability of soft magnetic powder by controlling the shape magnetic anisotropy of the powders and through the preparation of amorphous nanoparticles. For this purpose, the effect of the shape magnetic anisotropy of amorphous Fe-B-P nanoparticles is observed through a magnetic field and the frequency characteristics and permeability of these amorphous nanoparticles are observed. These characteristics are investigated by analyzing the composition of particles, crystal structure, microstructure, magnetic properties, and permeability of particles. The composition, crystal structure, and microstructure of the particles are analyzed using inductively coupled plasma optical emission spectrometry, X-ray diffraction, scanning electron microscopy and focused ion beam analysis. The saturation magnetization and permeability are measured using a vibrating sample magnetometer and an LCR meter, respectively. It is confirmed that the shape magnetic anisotropy of the particles influences the permeability. Finally, the permeability and frequency characteristics of the amorphous Fe-B-P nanoparticles are improved.

Organic-inorganic hybrid perovskite nanocrystals have attracted a lot of attention owing to their excellent optical properties such as high absorption coefficient, high diffusion length, and photoluminescence quantum yield in optoelectronic applications. Despite the many advantages of optoelectronic materials, understanding on how these materials interact with their environments is still lacking. In this study, the fluorescence properties of methylammonium lead bromide (CH3NH3PbBr3, MAPbBr3) nanoparticles are investigated for the detection of volatile organic compounds (VOCs) and aliphatic amines (monoethylamine, diethylamine, and trimethylamine). In particular, colloidal MAPbBr3 nanoparticles demonstrate a high selectivity in response to diethylamine, in which a significant photoluminescence (PL) quenching (~ 100%) is observed at a concentration of 100 ppm. This selectivity to the aliphatic amines may originate from the relative size of the amine molecules that must be accommodated in the perovskite crystals structure with a narrow range of tolerance factor. Sensitive PL response of MAPbBr3 nanocrystals suggests a simple and effective strategy for colorimetric and fluorescence sensing of aliphatic amines in organic solution phase.

본 연구에서는, 혐기성 처리수에 용해된 바이오가스의 회수를 위해 불화 실리카/고분자 중공사 복합막을 제조하 고 막접촉기에서의 성능을 평가하였다. 복합막은 상용 폴리에테르이미드인(PEI) Ultem®을 이용하여 만든 중공사막 표면에 불 화 실리카를 강력한 공유 결합을 통해 코팅하는 방법으로 제조되었다. 막접촉기는 바이오가스로 포화된 수용액을 중공사의 외부에 공급하고, 중공사 내부로 기체를 투과시키는 방법으로 운전하였다. 높은 공극률을 가진 중공사막(PEI-fSiO2-A)은 액상 속도가 0.03 m/s일 때 메탄 회수 유량이 8.25 × 10-5 cm3 (STP)/cm2⋅s에 달했고 불화 실리카에 의해 표면 소수성이 매우 높 아져 물과의 접촉각이 75.6°에서 120~122°로 향상되었다. 본 연구에서 제조된 복합막은 바이오가스의 투과 속도와 소수성 모 두에서 탈기용으로 제조된 상용 폴리프로필렌 막보다 우수한 성능을 나타냈다.

CeO2 nanoparticles, employed in a lot of fields due to their excellent oxidation and reduction properties, are synthesized through a solvothermal process, and a high specific surface area is shown by controlling, among various process parameters in the solvothermal process, the type of solvent. The synthesized CeO2 nanoparticles are about 11~13 nm in the crystallite size and their specific surface area is about 65.38~84.65 m2/g, depending on the amount of ethanol contained in the solvent for the solvothermal process; all synthesized CeO2 nanoparticles shows a fluorite structure. The dispersibility and microstructure of the synthesized CeO2 nanoparticles are investigated according to the species of dispersant and the pH value of the solution; an improvement in dispersibility is shown with the addition of dispersants and control of the pH. Various dispersing properties appear according to the dispersant species and pH in the solution with the synthesized CeO2 nanoparticles, indicating that improved dispersing properties in the synthesized CeO2 nanoparticles can be secured by applying dispersant and pH control simultaneously.

This research is conducted to analyze the compatibility of used monomers and produce the high functional hydrogel ophthalmic polymer containing silane and nanoparticles. VTMS (vinyltrimethoxysilane), TAVS [Triacetoxy(vinyl)silane] and cobalt oxide nanoparticles are used as additives for the basic combination of SilM (silicone monomer), MMA (methyl methacrylate) and MA (methyl acrylate). Also, the materials are copolymerized with EGDMA (ethylene glycol dimethacrylate) as cross-linking agent, AIBN (thermal polymerization initiator) as the initiator. It is judged that the lenses of all combinations are optically excellent and thus have good compatibility. Measurement of the optical and physical characteristics of the manufactured hydrophilic ophthalmic polymer are different in each case. Especially for TAVS, the addition of cobalt oxide nanoparticles increases the oxygen permeability. These materials are considered to create synergy, so they can be used in functional hydrogel ophthalmic lenses.

We prepare ZnO nanoparticles by environmentally friendly synthesis using Cyathea nilgiriensis leaf extract. Various phytochemical constituents are identified through the assessment of ethanolic extract of plant Cyathea nilgiriensis holttum by GC-MS analysis. The formation of ZnO nanoparticles is confirmed by FT-IR, XRD, SEM-EDX, TEM, SAED and PSA analysis. TEM observation reveals that the biosynthesized ZnO nanopowder has a hexagonal structure. The calculated average crystallite size from the high intense plane of (1 0 1) is 29.11 nm. The particle size, determined by TEM analysis, is in good agreement with that obtained by XRD analysis. We confirm the formation of biomolecules in plant extract by FT-IR analysis and propose a possible formation mechanism of ZnO nanoparticles. Disc diffusion method is used for the analyses of antimicrobial activity of ZnO nanoparticles. The synthesized ZnO nanoparticles exhibit antimicrobial effect in disc diffusion experiments. The biosynthesized ZnO nanoparticles display good antibacterial performance against B. subtilis (Gram-positive bacteria) and K. pneumonia (Gram-negative bacteria). Bio-synthesized nanoparticles using green method are found to possess good antimicrobial performance.

Fluorescent nanoparticles are characterized by their unique properties such as luminescence, optical transparency, and sensitivity to various chemical environments. For example, semiconductor nanocrystals (quantum dots), which are nanophosphors doped with transition metal or rare earth ions, can be classified as fluorescent nanoparticles. Tuning their optical and physico-chemical properties can be carried out by considering and taking advantage of nanoscale effects. For instance, quantum confinement causes a much higher fluorescence with nanoparticles than with their bulk counterparts. Recently, various types of fluorescent nanoparticles have been synthesized to extend their applications to other fields. In this study, State-of-the-art fluorescent nanoparticles are reviewed with emphasis on their analytical and anti-counterfeiting applications and synthesis processes. Moreover, the fundamental principles behind the exceptional properties of fluorescent nanoparticles are discussed.

Environmental pollution remains a considerable health risk source all over the world; however, hazards are usually higher in developing countries. Iraq has long been suffering from the problem of pollution and how to treat pollution. Photocatalytic degradation has turned out to be most productive process for dye degradation. In this investigation, Rhodamine B (RhB), dye has been selected for degradation under visible light illumination. To address this issue, we fabricate erbium trioxide nanoparticles (Er2O3/NPs). Erbium trioxide nanoparticles are prepared and utilized for photo-catalytic degradation. The characterization of Er2O3/NPs is described and confirmed by utilizing of XRD (X-ray diffraction) and SEM (Scanning Electron Microscopy). The average size of Er2O3 nanoparticles is observed to be 16.00 nm. Er2O3/NPs is investigated for its ability of photo-catalytic degradation through certain selected parameters such as concentration and time. The methodological results show that the synthesized Er2O3/NPs is a good photo-catalytic for Rhodamine degradation.