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Sine-Generated Curves: Theoretical and Empirical Notes

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Advances in Pure Mathematics 2015年第11期5卷 689-702页

作者： Dean Hathout flintridge preparatory school La Canada CA USA

Sine-generated curves belong to a class of intrinsic functions which describe a curve by specifying its “direction angle”. The curve is determined by ω, the maximum angle which the curve makes with the horizontal, and the fact that the direction angle changes in a sinusoidal fashion along the path. Sine-generated curves are shown to be excellent approximations to the path of minimal average curvature, and expressions for radius of curvature and curve sinuosity are derived.

关键词： Parametric Curves Calculus of Variations Optimization

Structural analysis by Rietveld refinement of calcium and lanthanum phosphosilicate apatites

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Journal of Rare Earths 2013年第9期31卷 897-904页

作者： Hela Njema Khaled Boughzala Habib Boughzala Khaled Bouzouita Laboratory of Industrial Chemistry National School of Engineering of Sfax preparatory Institute for Engineering Studies of Monastir Laboratory of Materials and Crystallochemistry Preparatory Institute for Engineering Studies of Nabeul

Britholites with the general formula Ca10-xLnx（PO4）6-x（SiO4）xF2, （0≤x≤6） are considered to be promising matrices for the confinement of the by-products in the nuclear industry. A thermodynamic study showed that the stability of these compounds de-creased as the substitution rate increased. The present work was an attempt to gain more information about the structural changes in-duced by the substitution, in order to understand the observed stability decrease. The samples were successfully synthesized as a sin-gle-phase apatite by a solid-state reaction between 1200 and 1400 °C. The structural refinement indicated that the La3＋ions preferen-tially occupied the 6（h） sites. A progressive shift of F-along the c-axis outside its ideal position occurred as a result of the substitution increase. This might be the cause of the observed stability decrease, especially as the energies of the La-O, La-F and Si-O bonds are higher than those of Ca-O, Ca-F and P-O. The distribution of La3＋ between the two non-equivalent sites was confirmed by the charge distribution method.

关键词： britholites Rietveld refinement infrared spectroscopy charge distribution method rare earths

Sharp Threshold of Global Existence for a Nonlocal Nonlinear Schrdinger System in R^(3)

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Chinese Annals of Mathematics,Series B 2019年第1期40卷 131-160页

作者： Zaihui GAN Xin JIANG Jing LI Center for Applied Mathematics Tianjin University school of preparatory Education Xinjiang Normal University

In this paper, the authors investigate the sharp threshold of a three-dimensional nonlocal nonlinear Schr¨odinger system. It is a coupled system which provides the mathematical modeling of the spontaneous generation of a magnetic field in a cold plasma under the subsonic limit. The main difficulty of the proof lies in exploring the inner structure of the system due to the fact that the nonlocal effect may bring some hinderance for establishing the conservation quantities of the mass and of the energy, constructing the corresponding variational structure, and deriving the key estimates to gain the expected result. To overcome this, the authors must establish local well-posedness theory, and set up suitable variational structure depending crucially on the inner structure of the system under study, which leads to define proper functionals and a constrained variational problem. By building up two invariant manifolds and then making a priori estimates for these nonlocal terms, the authors figure out a sharp threshold of global existence for the system under consideration.

关键词： Nonlocal nonlinear Schrödinger system Sharp threshold Blow-up Global existence

IMPROVED GRADIENT METHOD FOR MONOTONE AND LIPSCHITZ CONTINUOUS MAPPINGS IN BANACH SPACES

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Acta Mathematica Scientia 2017年第2期37卷 342-354页

作者： Kazuhide NAKAJO Sundai preparatory school SurugadaiKandaChiyoda-kuTokyo 101-8313Japan

Let C be a nonempty closed convex subset of a 2-uniformly convex and uniformly smooth Banach space E and {An}n∈N be a family of monotone and Lipschitz continuos mappings of C into E＊. In this article, we consider the improved gradient method by the hybrid method in mathematical programming [i0] for solving the variational inequality problem for {AN} and prove strong convergence theorems. And we get several results which improve the well-known results in a real 2-uniformly convex and uniformly smooth Banach space and a real Hilbert space.

关键词： Variational inequality problem gradient method monotone operators 2-uniformly convex Banach space hybrid method

Ca^(2+) and OH^- release of ceramsites containing anorthite and gehlenite prepared from waste lime mud

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Journal of Environmental Sciences 2016年第9期28卷 91-99页

作者： Juan Qin Chuanmeng Yang Chong Cui Jiantao Huang Ahmad Hussain Hailong Ma school of Materials Science and Engineering Nanjing University of Science and Technology Institute of Ethnic preparatory Education Ningxia University

Lime mud is a kind of solid waste in the papermaking industry,which has been a source of serious environmental *** containing anorthite and gehlenite were prepared from lime mud and fly ash through the solid state reaction method at 1050°*** objective of this study was to explore the efficiency of Ca^2＋ and OH-release and assess the phosphorus and copper ion removal performance of the ceramsites via batch experiments,X-ray diffraction（XRD） and scanning electron microscopy（SEM）.The results show that Ca^2＋ and OH-were released from the ceramsites due to the dissolution of anorthite,gehlenite and available *** is also concluded that gehlenite had stronger capacity for Ca^2＋ and OH-release compared with *** Ca^2＋ release could be fit well by the Avrami kinetic *** of porosity,dosage and temperature were associated with increases in the concentrations of Ca^2＋ and *** different conditions,the ceramsites could maintain aqueous solutions in alkaline conditions（p H = 9.3–10.9） and the release of Ca^2＋ was not *** removal rates of phosphorus and copper ions were as high as 96.88% and 96.81%,*** final p H values of both phosphorus and copper ions solutions changed *** reuse of lime mud in the form of ceramsites is an effective strategy.

关键词： Lime mud Ceramsite Gehlenite Calcium ion PH value

Frictionless Multi-field Coupling Contact Problem for a Thermoelectric Layer Loaded by Two Rigid Punches

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Acta Mechanica Solida Sinica 2023年第2期36卷 282-292页

作者： Yali Zhang Hailiang Ma Juan Yang Shenghu Ding school of Mathematics and Statistics Ningxia UniversityYinchuan 750021China school of Ethnic preparatory Education Ningxia UniversityYinchuan 750021China

In this paper,the thermo-electro-mechanical coupling contact problem of thermoelectric material with double punches is analyzed *** the Fourier cosine transform technique,the thermo-electro-elastic problem is transformed into three sets of singular integral equations,which are numerically solved by the Gauss–Chebyshev integral formula according to the unknown normal electric current density,normal energy flux and normal contact *** a rigid flat indenter,the results can be covered by the degradation results of two rigid flat *** numerical results reveal the interaction between two punches and the effect of thermoelectric load on the indentation *** interaction between the two punches reduces the contact pressure at the inner edge of the indenter as the thermoelectric load increases while increasing the stress singularity at the outer *** change of punches’spacing makes the singularity of normal stress at the inner and outer edges *** results provide an in-depth understanding of the multi-region contact damage mechanism of thermoelectric material.

关键词： Thermoelectric material Two rigid punches Interaction Analytical solutions

Mechanical Properties of Autoclaved Shell-aggregate

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Journal of Wuhan University of Technology(Materials Science) 2011年第4期26卷 723-729页

作者：马海龙崔崇 school of Materials Science and Engineering Nanjing University of Science and Technology Institute of Ethnic preparatory Education Ningxia University

Waste solid propylene oxide sludge （POS） and fly ash were used as main raw material to prepare propylene oxide sludge aggregate （POSA） under the condition of autoclaved （180 ℃,1.0 MPa） curing. Three different test methods namely cylinder compressive strength （CCS）, individual aggregate compressive strength （IACS） and strength contribution rate （SCR） proposed were used to characterize the mechanical properties of the autoclaved POSA. POS shell-aggregate with SCR of 94% were prepared under the hydrothermal synthesis and autoclaved curing. The experimental results indicate that CCS and IACS have good consistency in characterizing mechanical properties of POSA. It is suggested that SCR not only can characterize the strength of POSA core, but also can reflect the effect of shell on the performance of POSA. By means of least square method, relationships between CCS and IACS, CCS and SCR, IACS and SCR were deduced.

关键词： propylene oxide sludge cylinder compressive strength strength contribution rate aggregate individual aggregate compressive strength

High-temperature Phase Transition and the Activity of Tobermorite

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Journal of Wuhan University of Technology(Materials Science) 2014年第2期29卷 298-301页

作者：杨秀丽崔崇 CUI Xiaoyu TANG Guodong MA Hailong school of Materials Science and Engineering Nanjing University of Science and Technology Institute of Ethnic preparatory Education Ningxia University

The high-temperature phase transition of tobermofite was investigated by TGA/DSC, X-ray diffraction and Infrared spectroscopy （IR）, respectively. The experimental results showed that Si-OH bonds were cleaved at 724℃ and dehydroxylation occured at the same time, implying that the crystal structure of tobermorite was broken. As a result, the dehydroxylatiun tobermorite was metastable state, exhibiting obviously hydrolysis activity. The suspension was alkaline and Ca^2＋ ions content reached a maximum value 4.76% after heat treatment at 724℃. The dehydroxylation tobermorite had potential reactive activity due to the strong hydrolysis activity. The disordered structure recombined to wollastonite, and the crystal structure became ordering and stable at 861℃. Finally, 2M-wollastonite structure can be found in the sample as the temperature reached up to 1 000℃.

关键词： reaction tobermorite crystal structure hydrolysis

Experimental investigation on SPS casing treatment with bias flow

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Chinese Journal of Aeronautics 2014年第6期27卷 1352-1362页

作者： Dong Xu Liu Xiaohua Sun Dakun Sun Xiaofeng school of Energy and Power Engineering Beihang University Aeroengine Airworthiness Certification Center preparatory Office China Academy of Civil Aviation Science and Technology

Generally, casing treatment（CT） is a passivity method to enhance the stall margin of fan/compressor. A novel casing treatment based on the small disturbance theory and vortex and wave interaction suggestion is a method combining passive control and active control, which has been proved effective at enhancing the stall margin of fan/compressor in experiment. In order to investigate the mechanism of this kind of casing treatment, an experimental investigation of a stall precursor-suppressed（SPS） casing treatment with air suction or blowing air is conducted in the present paper. The SPS casing treatment is designed to suppressing stall precursors to realize stall margin enhancement in turbomachinery. The experimental results show that the casing treatment with blowing air of small quantity can improve the stall margin by about 8% with about 1% efficiency loss. By contrast, the SPS casing treatment with micro-bias flow does not improve the stall margin much more than that without bias flow, even worse. Meanwhile, the present investigation has also attempted to reveal the mechanism of stall margin improvement with the casing *** is found that the stall margin improvements vary with the modification of the unsteady shedding flow and the unsteady wall boundary impedance. The experimental results agree fairly well with the theoretical prediction using a flow stability model of rotating stall.

关键词： Air blowing Air suction Casing treatment Fan stability Rotating stall