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Preparation of b-Ca3(PO4)2 bioceramic powderfrom calcium carbonate and phosphoric acid q
Yun Zhang,Guangfu Yin,Shifu Zhu,Dali Zhou,Yuehua Wang,Yong Li,Lin Luo 한국물리학회 2005 Current Applied Physics Vol.5 No.5
When preparing b-tricalcium phosphate (b-TCP) with Ca(NO3)2 or Ca(OH)2 as the raw materials, because of the problem ofltering, it is dicult to industrialize traditional methods. In this paper,b-TCP was prepared with calcium carbonate and phospho-ric acid. According to XRD spectrum, the precursor of this system is octacalcium phosphate (OCP) [Ca8H2(PO4)6Æ5H2O] instead ofnon-stoichiometric hydroxyapatite (HA) obtained from traditional methods, and thermodynamics mechanism of the reaction wasalso studied. The crystalb-TCP powders were obtained after the precursor had been calcined at 8501150.C for 2 h. SEM imagesshowed that hardening could eliminate the reunion to a great extent, and obtain dispersiveb-TCP powders with a particle diameterbetween 0.5 and 2.0l m. The main advantages of this process over traditional methods are the fast reaction rate, the easy ltering,the ne particle size and the minimum impurity..
Preparation and photoluminescence properties of the Eu2+, Sm3+ co-doped Li2SrSiO4 phosphors
Lijuan Liu,Panli You,Guangfu Yin,Xiaoming Liao,Zhongbing Huang,Xianchun Chen,Yadong Yao 한국물리학회 2012 Current Applied Physics Vol.12 No.4
A series of Eu2+ and Sm3+ co-doped Li2SrSiO4 phosphors are prepared by the high temperature solidstate reaction. The morphology, structure and spectroscopic properties of the prepared samples are characterized by scanning electron microscopy, X-ray diffraction, diffuse reflection spectra, photoluminescence spectra and electron paramagnetic resonance spectra, respectively. The effect of Sm3þdoping concentration on the photoluminescence intensity of the prepared samples is also investigated. The results indicate that the crystal structure of Li2SrSiO4 is not changed with the Eu2+, Sm3+ co-doping. The spherical-like particle size of the obtained product is about 20-30 nm in diameter. When the Sm3+ concentration is 0.3 mol% and the Eu2+ concentration is 0.7 mol%, the phosphors show the maximum emission intensity, which is 50% higher than that of Eu2+ doped Li2SrSiO4. Excited at 420 nm, the phosphor presents a single broad emission band peaking at 558 nm, which is ascribed to the 4f65d1 / 4f7 transitions of Eu2+ and 4G5/2 / 6H5/2 and 4G5/2 / 6H7/2 transitions of Sm3+. The Commission International de I0Eclairage chromaticity coordinates of Li2SrSiO4:0.7 mol% Eu2+, 0.3 mol%Sm3+ are x = 0.28, y = 0.28. A series of Eu2+ and Sm3+ co-doped Li2SrSiO4 phosphors are prepared by the high temperature solidstate reaction. The morphology, structure and spectroscopic properties of the prepared samples are characterized by scanning electron microscopy, X-ray diffraction, diffuse reflection spectra, photoluminescence spectra and electron paramagnetic resonance spectra, respectively. The effect of Sm3þdoping concentration on the photoluminescence intensity of the prepared samples is also investigated. The results indicate that the crystal structure of Li2SrSiO4 is not changed with the Eu2+, Sm3+ co-doping. The spherical-like particle size of the obtained product is about 20-30 nm in diameter. When the Sm3+ concentration is 0.3 mol% and the Eu2+ concentration is 0.7 mol%, the phosphors show the maximum emission intensity, which is 50% higher than that of Eu2+ doped Li2SrSiO4. Excited at 420 nm, the phosphor presents a single broad emission band peaking at 558 nm, which is ascribed to the 4f65d1 / 4f7 transitions of Eu2+ and 4G5/2 / 6H5/2 and 4G5/2 / 6H7/2 transitions of Sm3+. The Commission International de I0Eclairage chromaticity coordinates of Li2SrSiO4:0.7 mol% Eu2+, 0.3 mol%Sm3+ are x = 0.28, y = 0.28.
Preparation and properties of the green-emitting phosphors NaCa0.98-xMgxPO4:
Bo Yue,Juan Gu,Guangfu Yin,Zhongbing Huang,Xiaoming Liao,Yadong Yao,Yunqing Kang,Panli You 한국물리학회 2010 Current Applied Physics Vol.10 No.4
In this study, a series of the green-emitting phosphors NaCa0.98-xMgxPO4:Eu2þ 0:02 was prepared through high temperature solid-state reaction. The structure and spectroscopic properties of these samples were characterized by XRD, FT-IR, reflectance spectra and photoluminescence (PL) spectra, respectively. The effect of Mg2+ co-doping concentration on the PL intensity of as-prepared samples was also investigated. The enhanced intensities of excitation and emission band of Eu2+ and a slight red-shift of the emission peak were observed due to Mg2+ co-doping. When the x value is 0.08, the phosphors possessed the maximum emission intensity monitored at 360 nm and the emission spectrum shows a single band centered at about 500 nm. The obtained phosphors had strong absorption in near-UV zone (350–400 nm), which can match the emission of near-UV light-emitting diodes. The prepared material is potential green phosphors for white LEDs.
Xiaonan Liu,Gang He,Jin-shan Li,Guangfu Yin 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2017 NANO Vol.12 No.9
In this study, we synthesized Hematite nano rings using hydrothermal treatment. The experimental results demonstrated that the (001)-orientated Hematite nano rings were produced in all of the obtained products. To determine the formation mechanism of the (001) orientation, the lowest three index crystal faces of Hematite, Hematite (001), Hematite (101), and Hematite (104), were investigated with the Cambridge Sequential Total Energy Package (CASTEP) within the Materials Studio software environment (MS5.5) using the density functional theory (DFT). Our theoretical results showed that Hematite (001), the Hematite crystal with the lowest surface energy, had the greatest Hematite nano ring growth. In addition, we present the growth process of the Hematite nano rings based on our experimental and theoretical results.
The precipitation of three Ca-P phase whiskers from an acid solution through hydrolysis of urea
Yunqing Kang,Yunshan Liu,Zhongbing Huang,Yadong Yao,Xiaoming Liao,Li Liao,Guangfu Yin 한양대학교 세라믹연구소 2008 Journal of Ceramic Processing Research Vol.9 No.2
Hydroxyapatite (HA), beta-tricalcium phosphate (β-TCP) and dicalcium phosphate (DCP) whiskers with high aspect ratio and good crystallinity were successfully prepared by hydrolysis of urea in acid solutions at 90oC for 96 h. The precipitated whiskers were characterized by XRD, SEM and TEM. The lengths and aspect ratios of whiskers could be controlled by the precipitation agent, urea, with a proper incubation time. Results revealed good morphology and crystallinity of the precipitated whiskers without any impurities. TEM indicated single crystal diffraction patterns of HA and β-TCP were clearly identified. The high aspect ratio of whiskers could be potentially used as the scaffold in tissue engineering or filler in composite biomaterials to enhance mechanical properties. Hydroxyapatite (HA), beta-tricalcium phosphate (β-TCP) and dicalcium phosphate (DCP) whiskers with high aspect ratio and good crystallinity were successfully prepared by hydrolysis of urea in acid solutions at 90oC for 96 h. The precipitated whiskers were characterized by XRD, SEM and TEM. The lengths and aspect ratios of whiskers could be controlled by the precipitation agent, urea, with a proper incubation time. Results revealed good morphology and crystallinity of the precipitated whiskers without any impurities. TEM indicated single crystal diffraction patterns of HA and β-TCP were clearly identified. The high aspect ratio of whiskers could be potentially used as the scaffold in tissue engineering or filler in composite biomaterials to enhance mechanical properties.