Showing papers by "Wuhan University of Technology published in 1991"
TL;DR: Thin vanadium oxide films were made by vacuum evaporation followed by the annealing posttreatment in the presence of air to establish VO(2) films with a well defined semiconductor-metal transition and concomitant thermochromic switching.
Abstract: Thin vanadium oxide films were made by vacuum evaporation followed by the annealing posttreatment in the presence of air. The thickness increased by a factor as large as ~2.3 on oxidation. Electron diffractograms indicated a bcc → monoclinic transformation during the annealing, and electron micrographs showed pronounced grain growth. Temperature-dependent electrical conductivity as well as spectral transmittance was measured vs annealing time. At an initial thickness of 0.12 μm, it took a few hours to establish VO2 films with a well defined semiconductor–metal transition and concomitant thermochromic switching at ~57°C.
60 citations
TL;DR: It is proved that there exist 4-{v; k,k, k, k; k; λ} supplementary difference sets (SDSs) with v = q2, q ≡ 1 (mod 4) a prime power, k = q(q − 1) 2 , λ = 4k − v, and Williamson matrices of order 4tv are proved.
25 citations
01 Nov 1991
TL;DR: In this paper, Li et al. showed that both the Fe2 and Fe3+ ions are present in the phosphate glasses, and that Fe2+ ions were coordinated with both four and six oxygen.
Abstract: Lithium phosphate glasses with different iron oxide contents were prepared using a rapid quenching technique and their glass transition temperatures (Tg), densities (d) and refractive indexes (n) were measured.X-ray photoelectron spectroscopy(XPS), infrared spectroscopy(IR) and Mossbauer spectroscopy have been used to study structure of the glasses and oxidation states of iron. These results indicate that both the Fe2+ and Fe3+ ions are present in the phosphate glasses, and that Fe2+ ions are coordinated with both four and six oxygen, but Fe2+ ions are only in six coordination, and that the physical and optical properties depended on the Fe2+/Fe ratio and Fe3+(4-coordinated)/Fe ratio. The XPS spectra and Mossbauer effect measurements showed that an increase in the Fe203 content causes a decrease of Fe2+/Fe ratio and an increase Fe3+(4-coordinated)/Fe ratio. The infrared measurements showed that an increase in the Fe203 content causes a change in coordination from Fe06 to FeO4.
10 citations
TL;DR: In this article, the electrical properties and structure of Niobium-doped TiC0.78 are discussed in terms of percolation theory, and the results obtained theoretically are consistent with the experimental results.
Abstract: The electrical properties and structure of niobium-doped TiC0.78 are discussed in terms of percolation theory. At a critical dopant concentration yc=0.143 (percolation threshold) of niobium atoms the conduction behaviour of the niodium-doped TiC0.78 gradually changes from semiconductor to metallic type, and in the structure the covalent bond network is mutually connected with the metal bond network. The results obtained theoretically are consistent with the experimental results.
6 citations
4 citations
TL;DR: In this paper, several different kinds of domain structures formed during phase transformation have been observed by means of high-resolution electron microscopy (HREM) in Ca4Al6S016.
Abstract: Several different kinds of domain structures formed during phase transformation have been observed by means of high-resolution electron microscopy (HREM) in Ca4Al6S016. They are 〈110〉 90 ° and 120 ° orientation variants and 〈1 1 0〉 translation variants found in the superstructure. These orientation variants are related to the lost symmetries of matrix and the number of them can be predicted according to the Van Tendeloo's conclusion. In addition to these domain structures, the 〈1 1 0〉 180 ° rotation domain with the characteristic feature of non-stoichiometry and {1 1 0} general domain have also been revealed in the matrix. The {1 1 0} and {2 1 1} small angle grain boundaries were studied as well.
4 citations
TL;DR: A series of melting-crystallization experiments on alkali basalt samples from Minqing, Fujian Province was carried out in dry and waterbearing systems at high pressures as discussed by the authors.
Abstract: A series of melting-crystallization experiments on alkali basalt samples from Minqing, Fujian Province was carried out in dry and waterbearing systems at high pressures. A high-pressure melting curve was obtained. The results indicate that clinopyroxene crystallized from basalt melt at 13.5–23.7 kbar. spinel at 23.7–28.6 kbar and garnet at > 28.6 kbar. With increasing pressure, the CaSiO3 contents of clinopyroxenes increase; and the FeSiO3 decreases, but the chemical composition of garnet does not show any significant difference. The minerals are larger and euhedral in the water-bearing system. Therefore, we consider that natural megacrysts of the basalt can crystallize from the water-bearing basalt magma at high pressure. So the megacrysts may be derived from the upper mantle as a result of magmatic crystallization-fractionation under high pressure.
2 citations
01 Jan 1991
TL;DR: In this paper, two kinds of micromechanical models of composite materials with fibers in two directions at right angles are advanced and compared with the predictions of the creep behavior for the composite by the creep mixture rules in this paper with the experimental data.
Abstract: Creep mixture rules of polymer matrix fiber-reinforced composite materials are studied systematically in this paper. Two kinds of micromechanical models of composite materials with fibers in two directions at right angles are advanced. The comparisons of the predictions of creep behavior for the composite by the creep mixture rules in this paper with the experimental data show that this theory is very precise for predicting the linear creep behavior of composite materials.
2 citations
TL;DR: Wang et al. as discussed by the authors proposed a method for image solids lab at Wuhan univ technol, wuhan 430070,wuhan, China.
Abstract: wuhan univ technol,wuhan 430070,peoples r china.;wang, yg (reprint author), acad sinica,inst met res,atom imaging solids lab,shenyang 110015,peoples r china
1 citations
01 Jan 1991
TL;DR: In this paper, a new method is used to calculate interlaminar stresses and edge effects in composite laminates, and the edge effects are calculated using a weighted average of the interlaminar stresses and edges.
Abstract: In this paper, a new method is used to calculate interlaminar stresses and edge effects in composite laminates
01 Jan 1991
TL;DR: In this paper, pyroelectric glass-ceramics of crystal structure β -BaB 2 O 4, have first been made satisfactorily in this work by crystallizing the glass in a temperature gradient.
Abstract: Pyroelectric glass-ceramics of crystal structure β -BaB 2 O 4 , have first been made satisfactorily in this work by crystallizing the glass in a temperature gradient. The microstructure of the materials prepared were investigated by IR, Raman spectra, XRD and SEM. The pyroelectric properties of BBO glass-ceramics were measured and compared with those of BBO single crystal and PZT ceramic. This kind of material has potential applications in the field of pyroelectric detectors.
TL;DR: In this paper, a strategy to optimize various non-coplanar laminate thin-walled structures is presented for the purposes of minimizing the total weight and maximizing the globe stiffness of the structures.
TL;DR: The determinate allocation decision model and the probabilistic allocation decisionmodel of a kind of renewable resource are separately studied by means of dynamic programming, and the optimal allocation policy is given under some special conditions.