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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
2.
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
3.
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
4.
5.
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
6.
7.
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
8.
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
9.
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
10.
Tatiana K. Zakharchenko Alina I. Belova Alexander S. Frolov Olesya O. Kapitanova Juan-Jesus Velasco-Velez Axel Knop-Gericke Denis Vyalikh Daniil M. Itkis Lada V. Yashina 《Topics in Catalysis》2018,61(20):2114-2122
One of the key factors responsible for the poor cycleability of Li–O2 batteries is a formation of byproducts from irreversible reactions between electrolyte and discharge product Li2O2 and/or intermediate LiO2. Among many solvents that are used as electrolyte component for Li–O2 batteries, acetonitrile (MeCN) is believed to be relatively stable towards oxidation. Using near ambient pressure X-ray photoemission spectroscopy (NAP XPS), we characterized the reactivity of MeCN in the Li–O2 battery. For this purpose, we designed the model electrochemical cell assembled with solid electrolyte. We discharged it first in O2 and then exposed to MeCN vapor. Further, the discharge was carried out in O2?+?MeCN mixture. We have demonstrated that being in contact with Li–O2 discharge products, MeCN oxidizes. This yields species that are weakly bonded to the surface and can be easily desorbed. That’s why they cannot be detected by the conventional XPS. Our results suggest that the respective chemical process most probably does not give rise to electrode passivation but can decrease considerably the Coulombic efficiency of the battery. 相似文献
11.
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
12.
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
13.
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
14.
Marco Ocsachoque Jose Bengoa Delia Gazzoli María Gloria González 《Catalysis Letters》2011,141(11):1643-1650
Abstract
The Rh/α-Al2O3 catalyst was modified by CeO2 in order to improve the thermal stability and the carbon deposition resistance during the CO2 reforming of methane The carbon formation was determined by TPO, TEM and Raman spectroscopy. Characterization results showed that the incorporation of Ce in the support inhibits the carbon deposition, increasing the useful life and the stability of the Rh base catalysts. 相似文献15.
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
16.
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
17.
Ternary IrO2–Sb2O5–SnO2 anode has shown its superiorities over IrO2 and many other electrocatalysts for O2 evolution, in terms of electrochemical stability, activity and cost. The performance of IrO2–Sb2O5–SnO2 anodes is affected by its electrochemical properties and operating conditions. In this paper, the electrochemical stability
and activity of the Ti/IrO2–Sb2O5–SnO2 anodes prepared with three different geometries were investigated under different operating conditions. It was found that
anodes with large mean curvature have high electrochemical stability. Although increasing temperature results in a decrease
in the stability of Ti/IrO2–Sb2O5–SnO2, the anode with a mean curvature of 200 m−1 still shows acceptable service life even at 70 °C. This tolerance of high temperature was attributed to the thermal expansion
difference between the substrate and the coating layer, the redox window for Ir(V)/Ir(IV) conversion, and the redox reversibility
of Sb and Sn species in the coating layer. 相似文献
18.
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
19.
Crystallization of zeolites from the gels of the (3–x)К2О–xR2O(RO)–0.05Na2O–Al2O3–5SiO2–100H2O composition where x was varied from 0 to 3 and R = Li, Na, Rb, Cs, Ba, tetraethylammonium, tetrapropylammonium, and tetrabutylammonium, has been performed by hydrothermal synthesis. The influence of various cationic ratios on the final product of crystallization depending on the synthesis temperature has been studied at constant SiO2: A2lO3 and H2O: SiО2 ratios. The correlation between the cationic composition of the initial gels, their structure, and the structure of the crystallizing zeolites has been estimated. 相似文献
20.
Pawel Mierczynski Radoslaw Ciesielski Adam Kedziora Waldemar Maniukiewicz Tomasz P. Maniecki 《Catalysis in Industry》2017,9(2):99-103
Monometallic copper and bimetallic palladium-copper catalysts supported on ZnO–Al2O3 and ZrO2–Al2O3 were prepared by conventional impregnation method and tested in methanol synthesis reaction under elevated pressure (3.5 MPa) in gradientless reactor at 220°C. The physicochemical properties of prepared catalytic systems were studied using BET, X-ray, TPR-H2, TPD-NH3 techniques. The promotion effect of palladium on catalytic activity and selectivity of copper supported catalyst in methanol synthesis reaction was proven. The highest activity of this system is explained by the Pd–Cu alloy formation. 相似文献