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1.
Sr2CeO4/Ln3+ (Ln = Er, Ho, Tm) phosphors were synthesized with the microwave radiation method for the first time. The luminescent properties
of the samples were investigated and the up-conversion luminescence of Er3+, Ho3+ and Tm3+ doped Sr2CeO4 phosphors was observed. The spectra indicate that the energy transfer takes place from the triplet excited state of MLCT
(metal-to-ligand charge transfer) state for Sr2CeO4 (sensitizer) to the rare earth ions (activator).
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Translated from Journal of Hebei Normal University (Natural Science Edition), 2007, 31(2): 212–216 [译自: 河北师范大学学报 (自然科学版)] 相似文献
2.
ZrWMoO8 powders with different morphologies were obtained using ammonium tungstate, molybdate tungstate and zirconium tungstate as
the starting materials by dehydrating the precursor ZrWMoO7(OH)2(H2O)2. The precursor was studied by thermo-gravimetric and differential scanning calorimetry (TG-DSC). The influence of the gelling
agents (HCl, HClO4, HNO3, H2SO4 and H3PO4) on the crystallization process and crystal morphology of the products prepared was investigated by X-ray powder diffraction
(XRD), scanning electron micrograph (SEM) and X-ray fluorescence spectrometer (XRF). Results showed that the morphology of
the ZrWMoO8 particles can be simply adjusted by changing the gelling agents, and the thermal expansion coefficients of cubic ZrWMoO8 prepared in HCl solution are −3.84 × 10−6 K−1 from 100°C to 700°C.
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Translated from Chemical Journal of Chinese University, 2007, 28(3): 397–401 [译自: 高等学校化学学报] 相似文献
3.
Liangzhun Yang Min Fang Yuejiao Liu Chao Liu Xiuying Wang Xibin Yu 《Frontiers of Chemistry in China》2007,2(4):442-446
The luminous materials of CaSiO3: Pb, Mn were synthesized by sol-gel method and ultrasound technology. The properties of the phosphors were characterized
by luminescence spectrum, differential thermal analysis and thermal gravimetry analysis (DTA-TG), X-ray diffraction (XRD),
Fourier transform infrared spectrometer (FT-IR) and transmission electron microscopy (TEM). The effects of factors such as
the synthetic material compositions, ultrasound time and annealed temperature on phosphorescent brightness of sample were
studied and the optimum synthetic conditions were determined. The results show that, compared with the sample made by the
high temperature solid-state reaction, the luminescent intensity of the CaSiO3: Pb, Mn sample increased by about 200% and the mean diameter of particles of the sample decreased by about 300 nm.
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Translated from Chemical Research and Application, 2007, 19(2): 140–144 [译自: 化学研究与应用] 相似文献
4.
A nano-alumina with high specific area was prepared using a homogeneous precipitation method with titanium dioxide and barium
oxide as modifying additives. Results showed that 5 wt% TiO2 or BaO added in the alumina gels can decrease the particle size and increase the specific area, but excessive TiO2 or BaO could deteriorate the properties of α-Al2O3.
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Translated from Journal of Shandong University of Technology (Natural Science Edition), 2007, 27(3): 23–26 [译自: 山东理工大学学报(自然科学版)] 相似文献
5.
Xianru Pei Xiaodong Wang Shunli Zhang Jingwei Zhang Jianjun Yang Zhensheng Jin 《Frontiers of Chemistry in China》2007,2(3):265-269
Nanotube Li-Ti-O compound with high surface (198.6 m2·g−1) was prepared by a method involving the treatment of nanotube Na2Ti2O5·H2O in molten LiNO3 and characterization by means of transmission electron microscopy (TEM), energy-dispersive spectra (EDS), X-ray diffraction
(XRD), X-ray photoelectron spectroscopy (XPS), and thermogravimetry-differential thermal analysis (TG/DTG). Results show that
the nanotube Li-Ti-O compound prepared by this method involves two crystal phases: spinel Li2Ti2O4 and anatase LixTiO2 (x < 0.1). Li+ exhibits different Li1s binding energy in the two crystal phases. In ambient air, the Li-Ti-O compound adsorbs water easily,
and the chemically adsorbed water is difficult to remove below 400°C.
Translated from Chinese Journal of Inorganic Chemistry, 2006, 22(12): 2135–2139 [译自: 无机化学学报] 相似文献
6.
Bitao Su Ke Wang Jie Bai Hongmei Mu Yongchun Tong Shixiong Min Shixiong She Ziqiang Lei 《Frontiers of Chemistry in China》2007,2(4):364-368
Fe3+-doped TiO2 composite nanoparticles with different doping amounts were successfully synthesized using sol-gel method and characterized
by X-ray diffraction (XRD), transmission electron microscopy (TEM) and ultravioletvisible spectroscopy (UV-Vis) diffuse reflectance
spectra (DRS). The photocatalytic degradation of methylene blue was used as a model reaction to evaluate the photocatalytic
activity of Fe3+/TiO2 nanoparticles under visible light irradiation. The influence of doping amount of Fe3+ (ω: 0.00%–3.00%) on photocatalytic activities of TiO2 was investigated. Results show that the size of Fe3+/TiO2 particles decreases with the increase of the amount of Fe3+ and their absorption spectra are broaden and absorption intensities are also increased. Doping Fe3+ can control the conversion of TiO2 from anatase to rutile. The doping amount of Fe3+ remarkably affects the activity of the catalyst, and the optimum efficiency occurs at about the doping amount of 0.3%. The
appropriate doping of Fe3+ can markedly increase the catalytic activity of TiO2 under visible light irradiation.
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Translated from Journal of Northwest Normal University (Natural Science), 2006, 42(6): 55–56 [译自: 西北师范大学学报(自然科学版)] 相似文献
7.
Yongheng Zhang Yusheng Lin Chengbin Jing Yuhua Qin 《Journal of Dispersion Science and Technology》2013,34(7):1053-1058
A soft solution method for synthesizing nanocrystalline CeO2 powders via formation of cerium citrate compounds with subsequent thermal decomposition was studied. Increasing calcinations temperature could result in a larger crystalline size, while increasing the citric acid content resulted in the powders with less agglomeration. Using this method, the CeO2 particles with a crystalline size of about 4 nm could be obtained. Initial study demonstrated that the precursor prepared with polyacrlic acid resulted in the powders with a crystalline size of about 20–30 nm. 相似文献
8.
3-Ene-1, 5-diynes are important components of many enediyne antitumor agents and luminescent materials. A stereo-controlled
approach to the synthesis of E-enediynes was developed, and it consists of the following two steps: (1) a mild and economical synthesis of dihalo vinyl
derivatives via addition of CuBr2 to alkynes; (2) the Sonogashira coupling reaction of the dihalo vinyl derivatives with terminal alkynes to form conjugated
enediynes.
Translated from Chinese Journal of Organic Chemistry, 2006, 26(12): 1682–1685 [译自: 有机化学] 相似文献
9.
Yingpin Li Xiaoquan Zhou Huijing Zhou Zhurui Shen Tiehong Chen 《Frontiers of Chemistry in China》2008,3(2):128-132
Manganese dioxides with various morphologies were prepared using a common hydrothermalmethod without any templates or additives.
The evolution of the morphology was accompanied by the gradual conversion of the polymorphic forms from γ-type to β-type. Meanwhile, MnO2 microspheres, urchin-like nanostructures and nanowires were successfully synthesized. The products were characterized by
X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscope and transmission electron microscope. The
evolution process can be explained by the Ostwald Ripening mechanism.
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Translated from Chinese Journal of Chinese Universities 28(7): 1223–1226 [译自: 高等学校化学学报] 相似文献
10.
After preparing the precursor by a liquid precipitation method, a series of tin-zinc composite oxides with different components
and structures were synthesized as the anode materials for lithium ion batteries when the precursor was pyrolyzed at different
temperatures. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and electrochemical
measurements. The reversible capacity of amorphous ZnSnO3 is 844 mA · h/g in the first cycle and the charge capacity is 695 mA · h/g in the tenth cycle. The reversible capacity of
ZnO · SnO2 is 845 mA · h/g in the first cycle and the charge capacity is 508 mA · h/g in the tenth cycle. The reversible capacity of
SnO2 · Zn2SnO4 is 758 mA · h/g in the first cycle and the charge capacity is 455 mA · h/g in the tenth cycle. Results show that amorphous
ZnSnO3 exhibits the best electrochemical property among all of the tin-zinc composite oxides. With the formation of crystallites
in the samples, the electrochemical property of the tin-zinc composite oxides decreases.
Translated from Chem J Chin Univ, 2006, 27(12): 2252–2255 [译自: 高等学校化学学报] 相似文献
11.
Controlled/living photopolymerization of methyl methacrylate (MMA) in miniemulsion mediated by 4-hydroxy-2,2,6,6-tetramethyl-piperidinyloxy
(HTEMPO) was carried out at ambient temperatures. MMA miniemulsion was prepared by using an anionic surfactant with cetylalcohol
as a co-stabilizer. The photopolymerization led to stable lattices and they were obtained with no coagulation during synthesis
and no destabilization over time. It was found that the obtained MMA homopolymers exhibited relatively narrow molecular weight
distribution (PDI = 1.27 − 1.36) which was characterized by GPC. The plots of number-average molecular weight in (M
n) vs. conversion and ln([M0]/[M]) vs. time both were linear indicating that the reaction was a controlled/living free radical polymerization.
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Translated from Chemical Journal of Chinese Universities, 2007, 28(4): 774–778 [译自: 高等学校化学学报] 相似文献
12.
A. Mesquita M. I. B. Bernardi L. J. Q. Maia V. R. Mastelaro 《Journal of Thermal Analysis and Calorimetry》2007,87(3):747-751
Pb1–xLaxTiO3
(PLT) nanocrystalline powders were obtained by polymeric precursor method.
The samples were analyzed by differential scanning calorimetry (DSC) and thermogravimetry
(TG) techniques to characterize properly the distinct thermal events occurring
during synthesis. The X-ray diffraction patterns show a tetragonal structure
for the samples with x=0.10 and 0.15. An
increase of the lanthanum concentration to x=0.20
led to a highly symmetric structure, cubic on average. The powders obtained
at the end of the synthesis had an average particle size of 30 to 70 nm. 相似文献
13.
Hongbo Guan Pei Wang Biying Zhao Yuexiang Zhu Youchang Xie 《Frontiers of Chemistry in China》2007,2(2):204-208
Nanometer MgO samples with high surface area, small crystal size and mesoporous texture were synthesized by thermal decomposition
of MgC2O4 · 2H2O prepared from solid-state chemical reaction between H2C2O4 · 2H2O and Mg (CH3COO)2 · 4H2O. Steam produced during the decomposition process accelerated the sintering of MgO, and MgO with surface area as high as
412 m2 · g−1 was obtained through calcining its precursor in flowing dry nitrogen at 520°C for 4 h. The samples were characterized by
X-ray diffraction, N2 adsorption, transmission electron microscopy, thermogravimetry, and differential thermal analysis. The as-prepared MgO was
composed of nanocrystals with a size of about 4–5 nm and formed a wormhole-like porous structure. The MgO also had good thermal
stability, and its surface areas remained at 357 and 153 m2·g−1 after calcination at 600 and 800°C for 2 h, respectively. Compared with the MgO sample prepared by the precipitation method,
MgO prepared by solid-state chemical reaction has uniform pore size distribution, surface area, and crystal size. The solid-state
chemical method has the advantages of low cost, low pollution, and high yield, therefore it appears to be a promising method
in the industrial manufacture of nanometer MgO.
Translated from Chinese Journal of Catalysis, 2006, 27(9): 793–798 (in Chinese) 相似文献
14.
S. F. Santos M. C. de Andrade J. A. Sampaio A. B. da Luz T. Ogasawara 《Journal of Thermal Analysis and Calorimetry》2007,87(3):743-746
TiO2–CeO2 oxides
for application as ceramic pigments were synthesized by the Pechini method.
In the present work the polymeric network of the pigment precursor was studied
using thermal analysis. Results obtained using TG and DTA showed the occurrence
of three main mass loss stages and profiles associated to the decomposition
of the organic matter and crystallization. The kinetics of the degradation
was evaluated by means of TG applying different heating rates. The activation
energies (E
a) and
reaction order (n) for each stage were
determined using Horowitz–Metzger, Coats–Redfern, Kissinger and
Broido methods. Values of E
a
varying between 257–267 kJ mol–1 and n=0–1 were found. According to the kinetic
analysis the decomposition reactions were diffusion controlled. 相似文献
15.
A single phase of monoclinic MnV2O6 nanoflakes was prepared by a hydrothermal process at 180°C for 18 h, using Mn (CH3COO)2·4H2O and NH4VO3 as starting materials and using acetic acid to adjust the pH value of the reaction solution. The as-prepared samples were
characterized by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). X-ray photoelectron
spectrum (XPS) measurements further confirm the component of MnV2O6. Results indicated that the products consisted of a large quantity of compact accumulated nanoflakes, with average width
of 0.85 μm, thickness of 100 nm and lengths up to 1.7 μm.
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Translated from Journal of Inorganic Materials, 2007, 22(6): 1139–1141 [译自: 无机材料学报] 相似文献
16.
Xiaofeng Zhang Shen Lin Xinqing Chen Jiebo Chen Liuyi Yang Minghong Luo 《Frontiers of Chemistry in China》2007,2(4):419-421
Mesoporous aluminophosphate was prepared by using G4.0 poly(amido amine)dendrimer as a template and characterized by Fourier
transform infrared spectrometer (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and N2 adsorption/desorption methods. Results show that the title compound exhibits a typical mesoporous structure with the average
pore size from 5 to 8 nm. The formation mechanism of the nanoporous structure using dendrimer as a template was also discussed.
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Translated from Journal of Fujian Normal University (Natural Science Edition), 2007, 23(2): 67–70 [译自: 福建师范大学学报 (自然科学版)] 相似文献
17.
With the aim of improving the microstructures and properties of TiO2 pillared montmorillonite (MMT), a long-chain polymer (polyoxypropylenediamine, PPO-D 2000) was used as a template to synthesize
composite pillared MMT. The materials were characterized by X-ray powder diffraction (XRD), Fourier transform infrared (FT-IR)
spectrophotometer, Fourier Raman (FT-Raman) spectrophotometer, thermo-gravimeter/differential thermogravimeter (TG/DSC), transmission
electron microscopy (TEM), and Brunauer-Emmett-Teller (BET) methods. The results show that as compared to low-molecular weight
surfactant, this polymer significantly expanded the interlayer spacing and thus more TiO2 could be intercalated into MMT. The specific surface area of polymer/TiO2 pillared MMT was increased by 13% with comparison to TiO2 pillared MMT and rose to 241.52 m2/g. Both the pore diameter and volume are doubled, and thus the pore structure is optimized markedly. The investigation on
the photo-catalytic degradation of methyl orange in aqueous solution show that the modulation of polymer molecules raise the
adsorption content of montmorillonite and improve the photo-catalytic activity. Therefore, this process provides a novel alternative
to design and prepare the advanced eco-catalytic materials with high adsorption capacity and photo-catalytic activity.
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Translated from Huaxue Tongbao, 2007, 12: 936–941 [译自: 化学通报] 相似文献
18.
TiO2 films were prepared by sol-gel method. In order to improve the utilization of light, the technologies of implantation of
transition metal ions (V+ and Cr+) and electron beam irradiation to deposit noble metal particles (Ag and Pt) were used. A red shift was found in the spectrum
of modified TiO2 films. The photocatalytic experiments showed that the photocatalytic ability under visible light irradiation could be improved
dramatically by both the implantation of transition metal and the electron beam irradiation.
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Translated from Chinese Journal of Catalysis, 2007, 28(1): 39–44 [译自: 催化学报] 相似文献
19.
Xiao Yang Youyuan Huang Henghui Zhou Jitao Chen Xinxiang Zhang 《Frontiers of Chemistry in China》2008,3(1):64-69
LiCo0.2Ni0.4Mn0.4O2, as the cathode material for lithium ion batteries, was modified by TiO2-coating. The effect of TiO2-coating on the structure and electrochemical performance of LiCo0.2Ni0.4Mn0.4O2 was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS),
and galvanostatic charge-discharge tests. The results suggest that a small amount of TiO2-coating does not change the crystalline structure, but considerably improves the electrochemical performance of LiCo0.2Ni0.4Mn0.4O2 in terms of capacity delivery and cyclability. XPS measurements confirm that the improved electrochemical performance is
most possibly attributed to a decrease in interaction between the layered material and non-aqueous electrolyte during the
charge-discharge processes.
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Translated from Chinese Journal of Inorganic Chemistry, 2007, 23(5): 753–758 [译自: 无机化学学报] 相似文献
20.
Lingang Li Yu Tang Yuanming Zhang Jun Yang Biying Du 《Frontiers of Chemistry in China》2008,3(1):76-80
ZnS hollow nanospheres with holes were prepared by reacting ZnSO4 with H2S, the sulfide source formed in the reaction of CS2 with ethylenediamine, 1,3-propylenediamine, butylamine or 2-(2-aminoethylamino) ethanol, which also acted as a template agent,
at 50°C under agitation. The shape, particle size of about 100–850 nm and hole size of about 150–600 nm of ZnS hollow nanospheres
with holes were shown by SEM and TEM images. These ZnS nanospheres with β cubic ZnS phase and composed of 2–5 nm nanocrystals
were characterized by XRD and HRTEM. The blue shift of maximum absorption in UV-vis displayed the effect of quantum size.
The two amino groups of amine templates reacted favorably with Zn2+ to form uniform and relatively smooth ZnS nanospheres with holes, while hydroxyethyl played a disadvantageous role. A reasonable
mechanism of hole formation by H2S rushing out is suggested.
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Translated from Journal of Jinan University (Natural Science), 2007, 28(1): 92–95 [译自: 暨南大学学报(自然科学版)] 相似文献