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Grain refinement of bronze alloy by equal-channel angular pressing(ECAP) and its effect on corrosion behaviour

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Defence Technology（防务技术） 2016年第4期12卷 316-323页

作者： M.M.SADAWY M.GHANEM Mining and Pet. dept. Faculty of Engineering Al-Azhar University Mechanical dept. Faculty of Industrial Education Suez University

The corrosion behaviour of bronze alloy prepared by equal channel angular pressing(ECAP) was investigated in 3.5 wt. % Na Cl *** corrosion tests and different electrochemical techniques were carried out. The results showed that ECAPed bronze samples exhibited higher corrosion resistance compared with the as-cast alloy and the passive current density decreased with increasing number of passes. Moreover,the morphology of alloys indicated that the corrosion damage on the surface of ECAPed bronze was smooth and uniform while the as-cast alloy suffered from selective corrosion.

关键词： Bronze ECAP Corrosion resistance Passive film Pitting

Φ-INEQUALITIES AND LAWS OF LARGE NUMBERS OF HARDY MARTINGALETRANSFORMS

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Acta Mathematica Scientia 1997年第3期17卷 269-275页

作者：刘培德吐尔德别克 dept. of Math. Wuhan University Wuhan 430071 China dept. of Math. Xinjiang University Ulumuqi 830046 China

Using stopping time method we proved the Φ-inequalities, pointwise convergence, strong and weak laws of large numbers of Hardy martingale transforms with values in complex Banach spaces, and applying them to give sev... 详细信息

关键词： AUMD space Hardy martingale martinale transform geometry of complex Banach space

STUDY ON LIQUID CRYSTAL POLYMERS WITH TWO-DIMENSIONAL MESOGENIC UNITS

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Chinese Journal of Polymer Science 1993年第4期11卷 58-63页

作者：张春晓李自法周其凤周洪兵 Chem. dept. Zhengzhou Univ. Zhengzhou 450052 Chem. dept. Peking Univ. Beijing 100871

A series of liquid crystalline polymers with two-dimensional mesogenic units were synthesized by solution polycondensation at low temperature. All the polymers were liquid crystalline. The melting temperature T;（except that with substituent of methoxy） and the clearing temperature T;of the polymers change regularly with varying of the length of the alkyl substituent groups.

关键词： Liquid crystal polymer Two-dimensional mesogenic unit N-2 ', 5 '-dihydroxy benzylidene-4-alkoxyaniline Monotropic nematics

Generalized fuzzy ideals of near-rings

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Applied Mathematics(A Journal of Chinese Universities) 2009年第3期24卷 343-349页

作者： ZHAN Jian-ming Davvaz B. dept. of Math. Hubei Institute for Nationalities Enshi 445000 China dept. of Math. Yazd University Yazd Iran

The concept of（∈,∈∨q）-fuzzy subnear-rings（ideals） of a near-ring is introduced and some of its related properties are *** particular,the relationships among ordinary fuzzy subnear-rings（ideals）,（∈,∈∨ q）-fuzzy subnear-rings（ideals） and（∈,∈∨q）-fuzzy subnear-rings（ideals） of near-rings are ***,some characterization of [μ]t is given by means of（∈,∈∨ q）-fuzzy ideals.

关键词： near-ring subnear-ring (ideal) (∈,∈ ∨ q)-fuzzy subnear-ring (ideal) (∈ ∈∨ q)-fuzzy subnear-ring(ideal)

Growth of Mixed Rare Earth Tartrate Crystals (Y_(1-x)Sm_x)_2(C_4H_4O_6)_3·zH_2O from Silica Gels

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Journal of Materials Science & Technology 1996年第2期12卷 81-88页

作者： Anima Jain and P.N.Kotru(dept. of Physics, University of Jammu, Jammu-180 001, India)M.L.Kaul (dept. of Chemistry , University , University of Jammu, Jammu-180 001, India (To whom correspondence should be addressed) dept. of Physics University of Jammu Jammu-180 001 India dept. of Chemistry University of Jammu Jammu-180 001 India

Experiments performed on the grwth of mixed crystals of rare earth tartrates (Y1-xSmx)2 (C4H4O6)***2O (0≤x≤1) from silica gels at 35~40℃ and 25~30℃ employing single-diffusion technique. are discussed. The crystals maintain spherulitic morphology, irrespective of the value of x, concentration of upper and lower reactants, gel pH, gel age and gel temperature. Formation Of Liesegang rings in this system is a temperature dependent phenomenon. It is shown that with the increase of the value of x the system passes from Liesegangring phenomenon to singlezone phenomenon. Operative mechanism of crystallization in the higher (35~40℃) and lower temperature ranges (25~30℃) is explained. Seeded growth experiments indicate the possibility of increasing the size of the spherulites in the gel medium

关键词： Sm C4H4O6 Growth of Mixed Rare Earth Tartrate Crystals x)Sm_x zH2O from Silica Gels

Effects of Hyperfine and Dopant Cation Interactions on theDC-Electrical Conductivity of MnZn Ferrites

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Journal of Materials Science & Technology 1997年第6期13卷 467-470页

作者： M.M.Abou Sekkina(Chem. dept., Faculty of Science, Tanta University, Tanta, Egypt)A.M.El-Sayed(Inorganic Chemistry dept., National Research Centre, Dokki, Cairo, Egypt) Chem. dept. Faculty of Science Tanta University Tanta Egypt Inorganic Chemistry dept. National Research Centre Dokki Cairo Egypt

Samples of undoped, and CuO, CaO, Al2O3 as well as V2O5 doped MnZn ferrite were prepared using standard ceramic method. The X-ray diffraction results for the base and doped ferrite samples show a single phase with spinel cubic structure. The Mossbauer spectrum of the base sample indicates line broadening and overlapping due to relaxation of magnetic dipoles. The temperature dependence of DC-electrical conductivity has been discussed on the basis of electronic conduction (electron hopping) and ionic conduction mechanism.

关键词： Effects of Hyperfine and Dopant Cation Interactions on theDC-Electrical Conductivity of MnZn Ferrites

Hydrodynamic Performance of Vertical Porous Structures Under Regular Waves

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China Ocean Engineering 2013年第4期27卷 451-468页

作者： A.S.Koraim O.S.Rageh Water and Water Structure Eng. dept. Faculty of Eng. Zagazig University Irrigation and Hydraulics dept. Faculty of Eng. El-Mansoura University

The hydrodynamic efficiency of the vertical porous structures is investigated under regular waves by use of physical models. The hydrodynamic efficiency of the breakwater is presented in terms of the wave transmission （kt）, reflection （kr） and energy dissipation （ka） coefficients. Different wave and structural parameters affecting the breakwater efficiency are tested. It is found that, the transmission coefficient （kt） decreases with the increase of the relative water dept. （h/L）, the wave steepness （Hi^L）, the relative breakwater widths （B/L, B/h）, the relative breakwater height （D/h）, and the breakwater porosity （n）. The reflection coefficient （kr） takes the opposite trend of kt when D/h=l.25 and it decreases with the increasing h/L, HJL and B/L when D/h〈1.0. The dissipation coefficient （kd） increases with the increasing h/L, HilL and B/L when D/h〈_l.O and it decreases when D/h=l.25. In which, it is possible to achieve values ofkt smaller than 0.3, k~ larger than 0.5, and kd larger than 0.6 when D/h=1.25, B/h=0.6, h/L〉0.22, B/L〉O. 13, and H/L 〉0.04. Empirical equations are developed for the estimation of the transmission and reflection coefficients. The results of these equations are compared with other experimental and theoretical results and a reasonable agreement is obtained.

关键词： water waves porous breakwaters wave attenuation wave transmission wave reflection wave dissipation

Macroscopic Studies on the Properties of the Anodic Oxide Films on Titanium

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Journal of Materials Science & Technology 1998年第3期14卷 241-246页

作者： Mahdy, G.A. Mahmoud, S.S. Chemistry dept. Faculty of Science Helwan University Helwan Cairo Egypt Chemistry dept. University College for Women Ain-Shams University Helopolis Cairo Egypt

The effect of fluoride ions on the formation and dissolution behaviour of anodic oxide films on Ti has been investigated in acidic fluoride media (pH=1) using impedance and galvanostatic techniques. A5 the fluoride ion concentration and temperature increase the rate of oxide film formation decreases while the dissolution process increases. oxide film formed at high tem-perature and formation voltage was found to contain more defect sites in the film than that formed at a lower one. Activation energies are calculated during the oxide film formation and dissolution and found to be 20.76 and 28.72 kJ/mol, respectively. Formation rate and reciprocal capacitance data are reported as a function of polarizing current density. Values are recorded for the electrolytic parameters A and B. Potentiostatic curves are derived from the galvanostatic results.

关键词： Figure Macroscopic Studies on the Properties of the Anodic Oxide Films on Titanium

Magnetism and Its Dependence on Annealing Temperature for Sputtered Co/Cu Multilayers

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Journal of Materials Science & Technology 1998年第2期14卷 139-142页

作者： Gao, Ruwei Liu, Yihua Yan, Shishen Zhang, Deheng Zhang, Lin dept. of Physics Shandong University Jinan 250100 China

It was found that the easy magnetization axes of the films are parallel to the substrate, and the magnetic properties of both as-sputtered and annealed multilayers are isotropic in the film plane. The coercive field H//c is 4.8 kA/m and the ratio of remanence-to-saturation magnetization M//r/M//s is about 0.73 for as-sputtered samples. Both H//c and M//r/M//s increase with increasing annealing temperatures, especially when annealing temperatures are higher than 400 degree C. These experimental results can be interpreted by using the ferromagnetic exchange coupling and the pinning theory of the coercivity. (Edited author abstract) 13 Refs.

关键词： Cobalt alloys