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1.
The phase relationships in the Na2ZnP2O7–LiKZnP2O7 system are studied. They are represented by a mixture of the starting components in the subsolidus region. The eutectic was found at a temperature of 640°C and composition of 0.5LiKZnP2O7. The phase formation of this system is compared with the previously studied NaKZnP2O7–LiKZnP2O7 system. It is shown that a structural factor affects the geometry of the state diagrams. 相似文献
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J. E. Anderson R. S. Bubnova S. K. Filatov V. L. Ugolkov S. N. Britvin 《Glass Physics and Chemistry》2009,35(2):191-198
The thermal behavior of ammonioborite (NH4)3[B15O20(OH)8] · 4H2O is investigated using thermal X-ray diffraction, differential thermal analysis (DTA) in air and vacuum, and thermogravimetry. It is shown that the decomposition of the mineral (dehydration, dehydroxylation, deammoniation) proceeds in several stages, and the dehydration is accompanied by the amorphization. The thermal expansion of ammonioborite is sharply anisotropic. As in the case of other hydrous pentaborates, the thermal expansion is maximum in the direction in which pentaborate groups alternate with ammonium cations. 相似文献
4.
Some photon interaction parameters such as mass attenuation coefficient, effective atomic number, half value layer, mean free path and electron density for 15ZnO–(17.5–x)Al2O3–xFe2O3–67.5P2O5 glass system (x = 0, 7.5, 12.5, 17.5) and 15ZnO–(25–x)Al2O3–xFe2O3–60P2O5 glass system (x = 0, 25) have been investigated in the photon energy range of 1 keV to 100 GeV. It has been observed that all the photon interaction parameters for the selected glass systems vary with the photon energy. Among the selected glass systems, the sample 15ZnO–25Fe2O3–60P2O5 glass system shows maximum values for mass attenuation coefficients, effective atomic numbers, electron densities and minimum values for mean free path and half value layer in the entire energy grid. 相似文献
5.
Ultrafast pump-probe and transient photoluminescence spectroscopy were used to investigate carrier dynamics in β-Ga2O3 nanowires converted to β-Ga2O3/Ga2S3 under H2S between 400 to 600 °C. The β-Ga2O3 nanowires exhibited broad blue emission with a lifetime of 2.4 ns which was strongly suppressed after processing at 500–600 °C giving rise to red emission centered at 680 nm with a lifetime of 19 μs. Differential absorption spectroscopy reveals that state filling occurs in states located below the conduction band edge before sulfurization, but free carrier absorption is dominant in the β-Ga2O3/Ga2S3 nanowires processed at 500 to 600 °C for probing wavelengths >500 nm related to secondary excitation of the photo-generated carriers from the mid-gap states into the conduction band of Ga2S3. 相似文献
6.
S. V. Mulevanov V. M. Nartsev A. N. Trofimov O. F. Beinarovich I. N. Gavrikova 《Glass Physics and Chemistry》2017,43(2):188-190
It is shown that the phase heterogeneity of SiO2–Na2O–Al2O3 glass has a liquation and crystallization nature, the balance between which is determined by the conditions of their synthesis. An increase in the aluminum oxide content decreases the number of liquation and crystallization sites, and also the linear sizes of the crystalline formations without eliminating the phase separation due to the liquation. The area of metastable immiscibility in the SiO2–Na2O–Al2O3 system, which is determined by scanning electron microscopy, is probably wider than the area detected by the optical methods. 相似文献
7.
E. A. Buluchevskii E. D. Fedorova A. V. Lavrenov M. V. Zhuravleva 《Catalysis in Industry》2018,10(2):118-125
The effect of the hydroisomerization conditions of the benzene-containing fraction of catalytic reforming gasoline on the yield and composition of products is studied on Pt/B2O3–Al2O3 and Pt/WO3–Al2O3 catalysts. These catalysts allow benzene to be completely removed from the raw material. At the same time, the greatest yields of liquid products are obtained with minimal losses of the octane number at 2 MPa, a mass feedstock hourly space velocity (MFHSV) of 2 h?1, and 325°C: 96.3 and 95.4 wt % on Pt/B2O3–Al2O3 and Pt/WO3–Al2O3 catalysts, respectively. The activity of the catalysts is maintained for 100 h during their operation. 相似文献
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An oxygen-diluted partially premixed/oxygen-enriched supplemental combustion (ODPP/OESC) counterflow flame is studied in this paper. Flame images are obtained through experiments and numerical simulations with the GRI-Mech 3.0 chemistry. The oxygen dilution effects are revealed by comparing the flame structures and emissions with those of a premixed flame and partially premixed flame (PPF) at the same equivalence ratio (?Σ = 0.95 and ? f = 1.4). The results show that both PPF and ODPP/OESC flames have distinct double flame structures; however, the location of the premixed combustion zone and the distance between premixed/nonpremixed combustion zone are significantly different for these two cases. For the ODPP/OESC flame, the temperature in the premixed combustion zone is lower and the premixed zone itself is located farther downstream from the fuel nozzle, which leads to reduction of NO and CO emissions, as compared to those of the PPF. Therefore, by adjusting the distribution of the oxygen concentration in the premixed and nonpremixed combustion zones, the ODPP/OESC can effectively balance the chemical reaction rate in the entire combustion zone and, consequently, reduce emissions. 相似文献
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L. V. Morozova M. V. Kalinina T. V. Khamova E. A. Vasil’eva O. A. Shilova 《Glass Physics and Chemistry》2016,42(4):408-413
The results of the studies of the process of fabricating ceramic filtration membranes in the system ZrO2(Y2O3)–Al2O3 are presented. The phase compositions of the precursor powders and sintered ceramics have been investigated and their porous structures have been determined. Two stages of the implementation of the technology were demonstrated: fabrication of substrates with an open porosity ranging from 20 to 47% and pore sizes in the 100–300 nm range, as well as the deposition of nanocrystalline aluminum oxide layers on them. It has been established that the pore size distribution in the membrane layer of α-Al2O3 is unimodal (from 30 to 100 nm). 相似文献
11.
Yanju Long Lingxin Li Shan Wang Yu Chen Lulu Wang Sifeng Zhang Lijun Luo Fengzhi Jiang 《Catalysis Letters》2018,148(12):3608-3617
A series of Bi2O3/Bi2O4 composites were prepared by calcining raw materials with different NaBiO3/KOH mass ratios. The Bi2O3/Bi2O4 photocatalysts were characterized by the various measurements and their photocatalytic performance was assessed by degradation of 17α-ethinyl estradiol (EE2). The Bi2O3/Bi2O4 photocatalysts have wider visible light absorption and lower fluorescence emission intensity than the commercial Bi2O3. So, they displayed superior performance in the degradation of EE2. After the adsorption equilibrium of EE2 was reached, the degradation efficiency of Bi2O3/Bi2O4 for EE2 can reach a maximum value of ~?100% in 12 min under the visible-light illumination. Degradation analysis results indicated that both holes (h+) and superoxide radical (·O2?) can affect the degradation efficiency of EE2. 相似文献
Graphical Abstract
12.
Xiaole Jiang Xingzheng Liu Qianqian Chen Risheng Jin Yu Lu Jingxiong Yu Ying Wu Yiming He 《Journal of Inorganic and Organometallic Polymers and Materials》2017,27(6):1683-1693
Ag2WO4/g-C3N4 composites with different Ag2WO4 concentration and calcination temperature were synthesized via a mixing and heating approach. Various techniques were used to investigate the characters of the as-prepared samples, such as thermogravimetric analysis, X-ray diffraction, Fourier transform infrared spectroscopy, UV–Vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and photoluminescence spectroscopy. The degradation of rhodamine B (20 ppm) under visible light was performed to investigate the photocatalytic activity of Ag2WO4/g-C3N4 composites. Results indicate that the Ag2WO4/g-C3N4 is actually Ag/Ag2WO4/g-C3N4 ternary system. 7.5 wt% Ag2WO4/g-C3N4 prepared at 300 °C presented the best photocatalytic performance in rhodamine B degradation. The degradation rate reaches 0.0679 min?1, which is 3.25 times higher than the value of pure g-C3N4. The enhanced activity is attributed to the synergetic effect of Ag2WO4, g-C3N4 and metal Ag. Additionally, cycling experiments also proved that the Ag2WO4/g-C3N4 photocatalyst has good stability. 相似文献
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F. Lian M. Gao W. H. Qiu P. Axmann M. Wohlfahrt-Mehrens 《Journal of Applied Electrochemistry》2012,42(6):409-417
With the aim of achieving a high-performance 0.5Li2MnO3·0.5LiMn0.5Ni0.5O2 material, a series of 0.5Li2MnO3·0.5LiMn
x
Ni
y
Fe(1−x−y)O2 (0.3 ≤ x ≤ 0.5, 0.4 ≤ y ≤ 0.5) samples with low Fe content was synthesized via coprecipitation of carbonates. Its crystal structure and electrochemical
performance were characterized by means of powder X-ray diffraction, field emission scanning electron microscopy, X-ray photoelectron
spectroscopy, galvanostatic charge/discharge testing, cyclic voltammetry, and electrochemical impedance spectra. Rietveld
refinements with a model integrating R
[`3] \overline{3}
m and Fm
[`3] \overline{3}
m indicate that a low concentration of Fe incorporated in 0.5Li2MnO3·0.5LiMn0.5Ni0.5O2 decrease a disordered cubic domain of the composite structure. The preferential distribution of Fe in cubic rock-salt contributes
to an unimaginable decrease of c-axis parameter of the predominant layered structure as the Fe content increases. Moreover, including Fe as a dopant can kinetically
improve crystallization and also change the ratio of Mn3+/Mn4+ and Ni3+/Ni2+. As a result, 0.5Li2MnO3·0.5LiMn0.4Ni0.5Fe0.1O2 exhibits lower Warburg impedance and higher reversible capacity than the undoped material. 相似文献
14.
Idris Kabalci Erkan Koc Sirri Semih Ozturk 《Journal of Inorganic and Organometallic Polymers and Materials》2017,27(3):788-794
Oxide based optical glass materials has important potential material in many applications from fiber optic to sensor due to the high transparency and amourphous structures. The objective of this study is to synthesize the novel optical glass materials based on the bismuth and aluminum contents to be able to determine the physical, chemical and mechanical properties by considering the systematic experimental steps. In this study, Bi2O3–Al2O3 based tellurite optical glasses have been prepared by using conventional melt quenching method as a function of the both Bi2O3 and Al2O3 compositions. There is a strong interactions between the glass former and modifier ions that might effect on the structure and mechanical properties. During the experimental steps, thermal, structural and mechanical properties of the prepared glass materials have been determined considering the DTA/DSC, FT-IR spectroscopy, SEM and Vicker’s hardness techniques, respectively. Thermal parameters, like glass transition, Tg, onset, Tx, crystallization, Tp, and melting, Tm, temperatures were obtained by using DTA scan. 相似文献
15.
Effects of ZnO–B2O3 (ZB) addition on the densification, phase evolution and microwaves dielectric properties of Ba4Sm9.33Ti18O54 (BST) ceramics for low-temperature fired applications have been investigated. The sintering temperature of BST ceramics can be effectively lowered to about 1000°C with introduction of ZB. Tungsten bronze like single phase is observed in the BST ceramics with 0.5 and 1.0% ZB. However, Sm2Ti2O7 secondary phase appears when ZB addition reaches 2%, and Sm2Ti2O7 phase gradually increases with the increase ZB addition. Microwave dielectric properties of the present ceramics are strongly dependent on phase constitution and density. Optimal microwave dielectric properties of ε = 63.4, Qf = 2830 GHz, τ f =–8.8 ppm/°C is obtained for BST ceramics with 1% ZB addition. 相似文献
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Vapor–liquid equilibria of binary components of the BrCF2COOCH3–CF3COOH–BrCF2COOH–CF3COOCH3 quaternary system have been studied experimentally at constant pressure. The experiments have been carried out on a modified Sventoslavskii ebulliometer. Using the Aspen Plus software package, the appropriate models have been selected and the vapor–liquid equilibria for six binary systems have been simulated. 相似文献
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The results of the studies of the conditions of the liquid-phase synthesis of highly dispersed xerogels with a low degree of agglomeration and precursor nanopowders (~10–12 nm) based on zirconium dioxide in the ZrO2–HfO2–Y2O3(CeO2) system are presented. The thermal decomposition of xerogels and formation of crystalline solid solutions with the structure of fluorite are investigated. The optimal conditions for the solidification of nanodispersed powders for fabricating compact ceramics based on solid solutions of ZrO2 and the physical–chemical properties of these ceramics are studied. 相似文献
18.
Fan Yang Zhiwei Wu Jianchao Ma Huabang Wang Yang Li Ligong Chen 《Catalysis Letters》2011,141(8):1142-1148
Abstract
Continuous synthesis of N-methylhomopiperazine over Cu–Cr–Mg/γ-Al2O3 has been developed. The doped Cr improves the dispersion of the Cu0 particles and inhibits the generation of CuAl2O4 so that the Cu0 particles are retained as the active sites. Doped Mg neutralizes the strong acid sites in Cu20Cr10Mg10/γ-Al2O3, and led to a decrease in coking side reactions. The reaction parameters were optimized and N-methylhomopiperazine was obtained in a yield of 66%. 相似文献19.
Yoshio Takasu Wataru Sugimoto Yoshinori Nishiki Shuji Nakamatsu 《Journal of Applied Electrochemistry》2010,40(10):1789-1795
The morphology and composition of RuO2–TiO2/Ti and IrO2–RuO2–TiO2/Ti anodes, which have been used for the production of chlorine for more than 10 years, were analyzed by various methods;
such as high-resolution scanning electron microscopy, high-resolution Auger electron spectroscopy, electron probe X-ray emission
microanalysis and X-ray diffraction analysis. Drastic changes in the surface morphology, including partial exfoliation of
a small amount of the oxide layer and a reduction in the content of ruthenium species through dissolution, were observed for
the RuO2–TiO2/Ti anode. For the IrO2–RuO2–TiO2/Ti anode, on the other hand, there were moderate changes in the surface morphology and moderate dissolution of iridium and
ruthenium species. 相似文献
20.
Vitrification in the Ga2S3–GeS2–PbF2 system is considered. The physicochemical properties of glasses, such as density, microhardness, electroconductivity, refraction index, and transmission percentage of specimens in visible and IR ranges of spectrum are studied; differential thermal analysis is carried out; and Raman and electron paramagnetic resonance spectra are investigated. 相似文献