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1.
BaCuQF (Q=S, Se, Te) materials exhibit band gaps that allow transmission of much of the visible spectrum. BaCuSF is transparent in thin-film form with a band gap of 3.1 eV. Band gap estimates for powders of the solid solution series BaCuS1−xSexF were obtained from wavelength-dependent diffuse-reflectance measurements using an integrating sphere. The band gap can be tuned by the substitution of Se for S to 2.9 eV for BaCuSeF. The decrease scales almost linearly with the increase in the volume of the tetragonal unit cell, which is determined primarily by the expansion of the a lattice parameter; the overall volume increase is 7.0% from x=0 to 1. Further reduction of the band gap is observed in BaCuSe1−xTexF solid solutions, where a unit cell volume increase of 5.5% produces a band gap of 2.7 eV in BaCuSe0.5Te0.5F. Powders and films of BaCuSF exhibit strong red luminescence under ultraviolet excitation, which is suppressed by K doping. Additional tuning of band gap and electrical properties (the materials are p-type conductors) can be achieved by replacing Ba with Sr. 相似文献
2.
John M. Jewell James Jaganathan Ishwar D. Aggarwal 《Journal of the American Ceramic Society》1991,74(4):788-796
The effect of controlled heterogeneous nucleation by platinum on the crystallization of a ZrF4 -BaF2 -LaF3 -AlF3 -NaF (ZBLAN) glass was studied. Various levels of platinum were incorporated into this glass by a combination of PtCl2 -doping and melting-atmosphere variation. The effect of doping levels and melting conditions on the incorporation of platinum and the subsequent nucleation of crystals was studied by optical microscopy, scanning electron microscopy, differential scanning calorimetry (DSC), and X-ray diffraction. Increased platinum in the glass resulted in an increased number of nucleation sites for the growth of β-ZrF4 -BaF2 crystals. Analysis of isothermal and ramp-rate DSC measurements indicated that the crystallization of this glass changed from surface controlled to bulk controlled with an increased number of nuclei. This was confirmed by optical microscopy. In addition, Avrami analysis of the isothermal crystallization data gave an accurate approximation of the number of nuclei in the glass. 相似文献
3.
提出以硼酸作为解蔽剂,FereneS作显色剂,直接测定氟化和氟酸盐中杂质铁量的方法。 相似文献
4.
Ziyang Jia Rui Ding Wujiang Yu Yi Li Ailin Wang Miao Liu Feng Yang Xiujuan Sun Enhui Liu 《Advanced functional materials》2022,32(1):2107674
Herein, a trimetallic Ni–Co–Zn perovskite fluoride (ABF3) (denoted as KNCZF) electrode material is explored for advanced aqueous supercabatteries (ASCBs), with KNCZF and activated carbon–FeBiCu@reduced graphene oxides (AC–FeBiCu@rGO) as cathode and anode, respectively, which outperform aqueous supercapacitors (ASCs) and batteries (ABs) with AC and FeBiCu@rGO anodes because of the synergistic effect of pseudocapacitive (KNCZF), capacitive (AC), and faradaic (FeBiCu@rGO) responses. One of the important findings is that the KNCZF shows a typical bulk phase conversion mechanism for charge storage in the alkaline media with the transition of ABF3 perovskite nanocrystals into amorphous metal oxides/(oxy)hydroxides nanosheets, showing the redox-active and redox-inert roles for the Ni/Co and Zn species, respectively, which can be deduced by various ex-situ techniques. Another interesting finding is that the redox-inert Zn species largely enhance the activity of Ni/Co redox-active species in the ABF3 materials, mainly owing to the promotion of surface electroactive sites, adsorption of OH?, and charge transfer of surface Ni/Co atoms by Zn-doping, which can be proved by ex-situ characterizations and theoretical calculations. Overall, this study reveals the structure–activity relationship and charge storage mechanisms of Zn-doping ABF3 materials for advanced ASCBs, showing a great impact on developing advanced electrochemical energy storage. 相似文献
5.
Uri Cohen 《Journal of Electronic Materials》1977,6(6):607-643
Electrodeposition of both epitaxial and polycrystalline continuous films of dense, coherent, and well-adherent silicon coatings
was achieved from molten fluorides. A dissolving Si anode and an operating temperature of about 750 C were utilized. Silicon
electrocrystallization epitaxy (ECE) produced films with the (111) orientation on Si substrates of the same orientation. The
unintentionally doped films were of p-type character with a resistivity in the range 0.05 - 0.10 Ω-cm. Polycrystalline Si
films were similarly electroplated onto various polycrystalline metal substrates. Uniform coherent, and well-adherent coatings
with grain diameters as large as 40 – 50 μm were obtained. The useful rate of electrodeposition of Si could be significantly
increased by the application of an alternating square wave pulse (ASWP)2technique. Cathodic current pulses as high as 300 mA/cm2 (growth rate of about 5 μm/min) were demonstrated. The cathodic current efficiencies, for all modes of growth, were about
70 – 100%. The effects of the various operating parameters, and some prospective applications to the fabrication of solar
cells, are discussed.
This was paper A-6 in the 18th Annual Electronic Materials Conference, Salt Lake City, June 23–25, 1976. 相似文献
6.
电解铝用氟化盐工业状况 总被引:4,自引:0,他引:4
从电解铝市场、氟化盐产能、产量、技术水平等方面,浅析了氟化盐(冰晶石、氟化铝)的现状及发展趋势,对氟化盐的市场做了预测,未来几年内,由于市场竞争更加激烈,环保呼声日见高涨,氟化盐行业的结构调整及技术进步将成为必然趋势。 相似文献
7.
《Journal of Nuclear Science and Technology》2013,50(9):828-832
Cellulose nitrate films were examined for thermal neutron monitoring in contact with several kinds of (n, α) converter materials such as a plastic sheet doped with 1% boron, a solidified boron oxide plate, a single crystal plate of boron oxide and that of lithium fluoride. After thermal neutron irradiation in a research reactor, the films were etched in alkaline solution. The etch-pits on the films were counted with a spark counter. The single crystal converter of lithium fluoride was found to be the most sensitive for thermal neutron. A method for producing the single crystal converter was described. Linear relation between thermal neutron fluence and spark counts was found to be in the fluence range of 2 × 10?6–3 × 107n/cm2 in case of using a lithium fluoride single crystal converter. 相似文献
8.
为改善推进剂的燃烧、点火性能,降低燃烧过程中的团聚,应用不同的实验处理方法将不同的氟化物添加入Mg/NaN03富燃料推进剂体系中,在燃烧室内氮气加压下点燃推进剂,收集固体燃烧产物,研究了氟化物对于体系燃烧特性的影响;SEM电镜分析了MglNaN03体系燃烧产物团聚的情况;对比了添加氟化物后体系燃烧产物的颗粒度;分析了不同氟化物的不同影响机理。结果表明,体系外加5%氟化物后,不同程度地降低了体系的燃速,改变了燃烧产物颗粒度分布,氟化镁的生成有利于降低产物的团聚程度。 相似文献
9.
High‐Curie‐Temperature Ferromagnetism in (Sc,Fe)F3 Fluorides and its Dependence on Chemical Valence 下载免费PDF全文
10.
《Journal of Nuclear Science and Technology》2013,50(8):633-634
Hydrogen gas evolution from water dispersing nanoparticles induced by 60Co γ-ray irradiation was studied. Nanoparticles of TiO2 and Al2O3 with average sizes of 7–33 nm supplied from several suppliers were examined. It was indicated that reactions enhancing the hydrogen evolution proceed on particle's surface. It was implied that the yield depends on size of agglomerated particle regardless of their primary particle size and chemical species. Reactions that enhance the hydrogen yields were discussed, and radiolysis process was concluded dominant in the total enhancement mechanism. 相似文献