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Fouling process and anti-fouling mechanisms of dynamic membrane assisted by photocatalytic oxidation under sub-critical fluxes

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Chinese Journal of Chemical Engineering 2019年第8期27卷 1798-1806页

作者： Tao yang fen Liu Houfeng Xiong Qiyong yang Fushan Chen Changchao Zhan School of Chemistry and Environment Engineering Jiujiang UniversityJiujiang 332005China Jiangxi Province Engineering Research Center of Ecological Chemical Industry Jiujiang UniversityJiujiang 332005China State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology Zhejiang University of TechnologyHangzhou 310014China

Membrane fouling is often considered as a hindrance for the application of microfiltration/ultrafiltration(MF/UF) for drinking water production. A novel process of photocatalytic membrane reactor/dynamic membrane(PMR/DM), operating in a continuous mode under sub-critical flux, was proposed for the mitigation of membrane fouling caused by humic acids(HAs) in water. The mechanism of membrane fouling alleviation with synergistic photocatalytic oxidation and dynamic layer isolating effect was comprehensively investigated from the characterization of foulant evolution responsible for the reversible and irreversible fouling. The results showed that the PMR/DM utilized photocatalytic oxidation to enhance the porosity and hydrophilicity of the fouling layer by converting the high molecular weight(MW) and hydrophobic HA molecules with carboxylic functional groups and aromatic structures into low-MW hydrophilic or transphilic fractions, including tryptophan-like or fulvic-like substances. The fouling layer formed in the PMR/DM by combination of photocatalytic oxidation and DM running at a sub-critical flux of 100 L·h^-1·m^-2, was more hydrophilic and more porous, resulting in the lowest trans-membrane pressure(TMP) growth rates, as compared to the processes of ceramic membrane(CM), DM and PMR/***, the dynamic layer prevented the foulants, particularly the high-MW hydrophobic fractions,from contacting the primary membrane, which enabled the membrane permeability to be restored easily.

关键词： Dynamic membrane Photocatalytic membrane reactor Humic acids Membrane fouling Sub-critical flux

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Room-temperature giant magnetotranstance effect in single-phase multiferroics

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Science China(Physics,Mechanics & Astronomy) 2021年第3期64卷 105-110页

作者： Yan-fen Chang Young Sun Beijing National Laboratory for Condensed Matter Physics and Beijing Advanced Innovation Center for Materials Genome Engineering Institute of PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Science University of Chinese Academy of SciencesBeijing 100190China Center of Quantum Materials and Devices Chongqing UniversityChongqing 401331China

Single-phase multiferroic materials are usually considered useless because of the weak magnetoelectric effects,low operating temperature,and small electric polarization induced by magnetic *** a result,current studies on applications of the magnetoelectric effects are mainly focusing on multiferroic heterostructures and *** we report a room-temperature giant effect in response to external magnetic fields in single-phase multiferroics.A low magnetic field of 1000 Oe applied on the spin-driven multiferroic hexaferrites BaSrCo_(2) Fe_(11)AlO_(22) and Ba_(0.9)Sr_(1.1)Co_(2) Fe_(11)AlO_(22)is able to cause a huge change in the linear magnetoelectric coefficient(α_(E)=dE/dH) by several orders,leading to a giant magnetotranstance(GMT) effect at room *** GMT effect is comparable to the well-known giant magnetoresistance(GMR) effect in magnetic multilayers,and thus opens up a door toward practical applications for single-phase multiferroics.

关键词： multiferroic magnetoelectric effect transtor

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Effect of Vegetation Changes on Soil Erosion on the Loess Plateau

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Pedosphere 2006年第4期16卷 420-427页

作者： ZHENG fen-Li State Key Laboratory of Soil Erosion and Dryland Farming in Loess Plateau Northwest A＆F University Yangling 712100 （China）.

Vegetation is one of the key factors affecting soil erosion on the Loess Plateau. The effects of vegetation destruction and vegetation restoration on soil erosion were quantified using data from long-term field runoff plots established on the eastern slope of the Ziwuling secondary forest region, China and a field survey. The results showed that before the secondary vegetation restoration period (before about 1866-1872), soil erosion in the Ziwuling region of the Loess Plateau was similar to the current erosion conditions in neighboring regions, where the soil erosion rate now is 8000 to 10000 t km-2 year-1. After the secondary vegetation restoration, soil erosion was very low; influences of rainfall and slope gradient on soil erosion were small; the vegetation effect on soil erosion was predominant; shallow gully and gully erosion ceased; and sediment deposition occurred in shallow gully and gully channels. In modern times when human activities destroyed secondary forests, soil erosion increased markedly, and erosion rates in the deforested lands reached 10000 to 24000 t km-2 year-1, which was 797 to 1682 times greater than those in the forested land prior to deforestation. Rainfall intensity and landform greatly affected the soil erosion process after deforestation. These results showed that accelerated erosion caused by vegetation destruction played a key role in soil degradation and eco-environmental deterioration in deforested regions.

关键词： deforestation Loess Plateau natural vegetation restoration soil erosion

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Triality and Dual Equivalence Between Dirac Field and Topologically Massive Gauge Field

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Communications in Theoretical Physics 2006年第3X期46卷 481-492页

作者： LIU Yu-fen Institute of Theoretical Physics Academia Sinica Beijing 100080 China

It is proved that there exists a vector representation of Dirac＇s spinor field and. in one sense it is equivalent to biquaternion （i.e. complexified quaternion） representation. This can be considered as a generalization of Cartan＇s idea of triality to Dirac＇s spinors. In the vector representation the first-order Dirac Lagrangian is dual-equivalent to the two-order Lagrangian of topologically massive gauge field. The potential field which corresponds to the Dirac field is obta/ned by using master （or parent） action approach. The novel gauge field is self-dual and contains both anti-symmetric Lee and symmetric Jordan structure.

关键词： triality biquatermion self-dual

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SHARP ESTIMATES OF QUASI-CONVEX MAPPINGS OF TYPE B AND ORDER α

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Acta Mathematica Scientia 2019年第5期39卷 1265-1276页

作者： Mingsheng LIU fen WU Yan yang School of Mathematical Sciences South China Normal University Guangzhou 510631 China School of Mathematics(Zhuhai) Sun Yat-Sen University Zhuhai 519080 China

In this paper,we first establish several sharp inequalities of homogeneous expansion for biholomorphic quasi-convex mappings of type B and order a on the unit ball E in a complex Banach space X by applying the method and technique of complex ***,as the application of these sharp inequalities,we derive the sharp estimate of third homogeneous expansions for the above mappings defined on the unit polydisk U^n in C^n.

关键词： quasi-convex mappings of type B and order α inequalities of homogeneous expansions the sharp estimate of third homogeneous expansions

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Effects of Accelerated Soil Erosion on Soil Nutrient Loss After Deforestation on the Loess Plateau

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Pedosphere 2005年第6期15卷 707-715页

作者： ZHENG fen-Li State Key Laboratory of Soil Erosion and Dryland Farming in Loess Plateau Institute of Soil and Water ConservationChinese Academy of Sciences and Ministry of Water Resources Yangling 712100 （China）

Soil erosion and nutrient losses on newly-deforested lands in the Ziwuling Region on the Loess Plateau of China were monitored to quantitatively evaluate the effects of accelerated soil erosion, caused by deforestation, on organic matter, nitrogen and phosphorus losses. Eight natural runoff plots were established on the loessial hill slopes representing different erosion patterns of dominant erosion processes including sheet, rill and shallow gully (similar to ephemeral gully). Sediment samples were collected after each erosive rainfall event. Results showed that soil nutrients losses increased with an increase of erosion intensity. Linear relations between the losses of organic matter, total N, NH4-N, and available P and erosion intensity were found. Nutrient content per unit amount of eroded sediment decreased from the sheet to the shallow gully erosion zones, whereas total nutrient loss increased. Compared with topsoil, nutrients in eroded sediment were enriched, especially available P and NH4-N. The intensity of soil nutrient losses was also closely related to soil erosion intensity and pattern with the most severe soil erosion and nutrient loss occurring in the shallow gully channels on loessial hill slopes. These research findings will help to improve the understanding of the relation between accelerated erosion process after deforestation and soil quality degradation and to design better eco-environmental rehabilitation schemes for the Loess Plateau.

关键词： accelerated soil erosion deforestation erosion intensity Loess Plateau nutrient loss

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Weighted composition operators from F(p,q,s) spaces to Bers-type spaces in the unit ball

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Applied Mathematics(A Journal of Chinese Universities) 2009年第4期24卷 462-472页

作者： LU Xiao-fen Department of Mathematics Huzhou Teachers College Huzhou 313000 China

This paper deals with the boundedness and compactness of the weighted composition operators from the F（p, q, s） spaces, including Hardy space, Bergman space, Qp space, BMOA space, Besov space and α-Bloch space, to ... 详细信息

关键词： F(p q s) space Bers-type space weighted composition operator unit ball

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EQ^(rot)_1 Nonconforming Finite Element Method for Nonlinear Dual Phase Lagging Heat Conduction Equations

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Acta Mathematicae Applicatae Sinica 2013年第1期29卷 201-214页

作者： Yan-min Zhao fen-ling Wang Dong-yang Shi School of Mathematics and Statistics Xuchang University Department of Mathematics Zhengzhou University

EQrot nonconforming finite element approximation to a class of nonlinear dual phase lagging heat conduction equations is discussed for semi-discrete and fully-discrete schemes. By use of a special property, that is, the consistency error of this element is of order O（h2） one order higher than its interpolation error O（h）, the superclose results of order O（h2） in broken Hi-norm are obtained. At the same time, the global superconvergence in broken Hi-norm is deduced by interpolation postprocessing technique. Moreover, the extrapolation result with order O（h4） is derived by constructing a new interpolation postprocessing operator and extrapolation scheme based on the known asymptotic expansion formulas of EQrot element. Finally, optimal error estimate is gained for a proposed fully-discrete scheme by different approaches from the previous literature.

关键词： nonlinear dual phase lagging heat conduction equations EQrot nonconforming finite element superclose and superconvergence extrapolation semi-discrete and fully-discrete schemes

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Superconvergence Analysis and Extrapolation of Quasi-Wilson Nonconforming Finite Element Method for Nonlinear Sobolev Equations

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Acta Mathematicae Applicatae Sinica 2013年第2期29卷 403-414页

作者： Dong-yang SHI fen-ling WANG Yan-min ZHAO Department of Mathematics Zhengzhou University School of Mathematics and Statistics Xuchang University

Quasi-Wilson nonconforming finite element approximation for a class of nonlinear Sobolev equa- tions is discussed on rectangular meshes. We first prove that this element has two special characters by novel approaches. One is that （Vh（U -- Ihu）,VhVh）h may be estimated as order O（h2） when u E H3（Ω）, where Iuu denotes the bilinear interpolation of u, vh is a polynomial belongs to quasi-Wilson finite element space and △h denotes the piecewise defined gradient operator, h is the mesh size tending to zero. The other is that the consistency error of this element is of order O（h2）/O（h3） in broken Hi-norm, which is one/two order higher than its interpolation error when u ε Ha（Ω）/H4 （（1）. Then we derive the optimal order error estimate and su- perclose property via mean-value method and the known high accuracy result of bilinear element. Furthermore, we deduce the global superconvergence through interpolation post processing technique. At last, an extrapola- tion result of order O（h3）, two order higher than traditional error estimate, is obtained by constructing a new suitable extrapolation scheme.

关键词： nonlinear Sobolev equations quasi-Wilson element superclose and superconvergence extrapola-tion

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Effect of manganese sulfide on the precipitation behavior of tin in steel

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International Journal of Minerals,Metallurgy and Materials 2014年第7期21卷 654-659页

作者： Gui-lin Sun Bo Song Ling-zhi yang Su-fen Tao Yong yang State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Department of Metallurgical Technology

Tramp elements such as tin are considered harmful to steel because of hot brittleness they induce at high temperatures. Because tramp elements retained in steel scrap will be enriched in new steel due to the difficultly of their removal, studies on the precipitation behavior of tin are essential. In this study, the effects of different inclusions on the precipitation behavior of tin in steel were studied. The results show that the tin-rich phase precipitates at austenite grain boundaries in an Fe-5%Sn alloy without MnS precipitates, whereas Sn precipitates at the boundaries of MnS inclusions in steel that contains MnS precipitates. MnS is more effective than silicon dioxide or aluminum oxide as a nucleation site for the precipitation of the tin phase, which is consistent with the disregistry between the lattice parameters of the tin phase and those of the inclusions.

关键词： steelmaking manganese sulfide tin precipitation heterogeneous nucleation

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