B.Q. Jiang
,
L. Gu
,
W.L. Zhang
,
Y.S. Sun and F. Lin Chemical Engineering Department of Nanchang University
,
Nanchang 330029
,
China
金属学报(英文版)
A ceramic tube supported γ alumina silica inorganic composite membrane was made by modifying a ceramic tube supported γ alumina film with a silica sol using sol gel method. The thickness of the silica thin film was 750? and the pore diameter was less than 5?.The prepared silica molecular sieve membrane displayed a high hydrogen permeability and high selectivities of H 2/N 2 and H 2/CO 2 gas mixtures. This composite membrane can be used to separate high purity hydrogen of more than 99 5% from various kinds of industrial waste gas mixtures containing hydrogen.
关键词:
silica
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null
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null
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null
W.L. Zhang
,
B.Q. Jiang
,
Y.S. Sun
,
F. Lin and L. Gu Chemical Engineering Department of Nanchang University
,
Nanchang 330029
,
China
金属学报(英文版)
A stable colloidal boehmite sol was made with the aluminium iso propoxide made in China and used to prepare the supported γ alumina membrane using sol gel method. The γ alumina thin layer was characterized by SEM, N 2 sorption method and permeation measurement. The γ alumina membrane was prepared with uniform surface, thickness of 3 μm and average diameter of about 5 nm. The permeabilities of the single gases of H 2, N 2, Ar and their separation factors were measured. The experimental data explained a behavior of Knudsen diffusion for the gas transport through the thin membrane.
关键词:
boehmite
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null
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null
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null
W.L. Zhang
,
R.J. Tang
,
W.X. Zhang
,
B. Peng
,
H.C. Jiang
,
H.W. Zhang
金属学报(英文版)
The magnetization reversal process of nano-size rectangle-shaped NiFe film elements with different aspect ratios have been investigated under the orthogonally applied magnetic fields by micromagnetic simulation. Different magnetization reversal modes can appear depending on whether the bias field is applied or not. When there is no bias field, double "C" state is the initial reversal state. However, when there is a bias field, "S" state is the starting mode. The larger the aspect ratio is, the larger the switching field is. But, when the aspect ratio is larger than 3, the increase of the switching field ceases. These results can provide useful information to the application of the patterned NiFe film with rectangular elements.
关键词:
NiFe film element
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null
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null
W.L. Zhang
材料科学技术（英文）
An axisymmetrical unit cell model was used to represent a bimodal Al alloy that was composed of both nano-grained (NG) and coarse-grained (CG) aluminum. Effects of microstructural and materials parameters on tensile properties of bimodal Al alloy were investigated by finite element method (FEM). The parameters analyzed included aspect ratios of CG Al and the unit cell, volume fraction of CG Al (VFCG), and yield strength and strain hardening exponent of CG Al. Aspect ratios of CG Al and the unit cell have no significant influence on tensile stress-strain response of the bimodal Al alloy. This phenomenon derives from the similarity in elastic modulus and coefficient of thermal expansion between CG Al and NG Al. Conversely, tensile properties of bimodal Al alloy are extremely sensitive to VFCG, yield strength and strain hardening exponent of CG Al. Specifically, as VFCG increases, both yield strength and ultimate tensile strength (UTS) of the bimodal Al alloy decreases, while uniform strain of bimodal Al alloy increases. In addition, an increase in yield strength of CG Al results in an increase in both yield stress and UTS of bimodal Al alloy and a decrease in uniform strain of bimodal Al alloy. The lower capability in lowering the increase of stress concentration in NG Al due to a higher yield strength of CG Al causes the lower uniform strain of the bimodal Al alloy. When strain hardening exponent of CG Al increases, 0.2% yield stress, UTS, and uniform strain of the bimodal Al alloy increases. This can be attributed to the increased work-hardening ability of CG Al with a higher strain hardening exponent.
关键词:
Nanomaterials
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null
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null
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null
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