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Effect of lanthanum on inclusions in non-oriented electrical steel slabs

Journal of Iron and Steel Research International 2024年第7期31卷 1680-1691页

作者： qiang Ren Zhi-yuan Hu Yun-xia Liu Wei-cheng Zhang Zi-qi Gao Li-feng Zhang School of Mechanical engineering Yanshan UniversityQinhuangdao 066004HebeiChina School of Metallurgical and Ecological engineering University of Science and Technology BeijingBeijing 100083China Research and Development department Shougang Zhixin Qian'an Electromagnetic Material Co.Ltd.Qian'an 064400HebeiChina School of Mechanical and Materials engineering North China University of TechnologyBeijing 100144China

The effect of lanthanum on the characteristics of inclusions in the slab of non-oriented electrical steels was investigated through industrial trials and thermodynamic *** number,size,and chemical composition of inclusions in the surface,one-quarter of thickness and the center of slabs with and without lanthanum addition were statistically analyzed using an automatic inclusion analysis *** the lanthanum-free slab,inclusions were predominately ***_(2)O_(3.,MgO,and AlN as well as a small number of Al_(2)O_(3.-MgO-CaO and *** number densities of oxide inclusions and AlN decreased from the surface to the center of the slab,which was ascribed to the difference in cooling intensity during the continuous *** the steel with lanthanum addition,inclusions were modified into LaAlO_(3. and La_(2)O_(2)S and gradually transformed into dual-phase MgO-La_(2)S3.with an increasing distance from the slab surface due to the reaction between the lanthanum-containing inclusion and the steel *** uneven distribution of oxide inclusions along the thickness of the slab was eliminated in the lanthanum-bearing slab because the dissolved oxygen was remarkably decreased by ***-bearing inclusions were more likely to agglomerate AlN by inducing the heterogeneous nucleation of AlN on their surface,while small-size ***_(2)O_(3. inclusions hardly showed a coarsening effect on the size of AlN.

关键词： Lanthanum-Inclusion Non-oriented electrical steel Aluminum nitride Heterogenous nucleation

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On the dynamics in a transitional boundary layer

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Communications in Nonlinear science and Numerical Simulation 2001年第3期6卷 111-171页

作者： C. B. LEE and R. LEE department of Mechanics and engineering science/State Key Laboratory for Studies of Turbulence and Complex Systems,{3., beijing 100871, China department of engineering Mechanics, Tsinghua university, beijing 100084, Chi department of Mechanics and engineering science / State Key Laboratory for Studies of Turbulence and Complex Systems Peking University Beijing 100871 China department of engineering Mechanics Tsinghua University Beijing 100084 China

A model is presented to describe the dynamic physical processes that occur in a transitional boundary layer flow. The CS-solitons, the closed vortex, the secondary closed vortex and the chain of ring-like vortices are postulated to be the basic flow structures of the transitional boundary layer as well as the turbulent boundary layer. It is argued that the central features of transitional and developed turbulent boundary layer flows can be explained in terms of how the series vortices interact with each other, and with the CS-solitons. The physical process that leads to the regeneration of the new closed vortex along the border of the CS-soliton, as well as the processes of evolution of the vortices to high frequency vortices, is described. The model is supported by the important developments in a number of "kernel" experiments, which illustrate both transitional and developed turbulent boundary layer. An important aspect of the model is that it has been formulated to be consistent with accepted rational mechanics concepts that are known to provide a proper physical description of other flows.

关键词： boundary layer transition dynamic processes onset of turbulence

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Synthesis of Bis(4'-hydroxyphenyl)-toluene-2, 4-diurethane for Main Chain Liquid Crystalline Poly(urethane-ester)s

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Chinese Chemical Letters 1998年第5期9卷 439-442页

作者： Yan qing LIAN Ming qi LI qi Xiang ZHOU De Shan LIU(Institute of {3. science and engineering, department of Chemical engineering,Tsinghua university, beijing 100084) Tsing Hua Univ Dept Chem Engn Inst Polymer Sci & Engn Beijing 100084 Peoples R China

A new methodology was advanced that mesogenic cores appeared after theformation of urethane groups and during the monomer-to-polymer transition. A newdiphenol monomer, bis(4'-hydroxy-phenyl)-toluene-2 (BHPTU), was obtainedby the reaction of 2,4-tolulene diisocyanate with hydroquinone in dioxane or N,N-dimethyl-acetandde. The reaction process was monitored by FTIR, and the product was investigated bylH NMR and elemental analysis (EA). A liquid crystalline poly(urethane-ester) was obtainedusing the BHPTU monomer.

关键词： liquid crystalline polymer poly(urethane-ester) synthesis

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FABRICATION AND AFM/FFM STUDIES OF C_(60)-CONTAINING POLYELECTROLYTE SELF-ASSEMBLED FILMS

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Chinese Journal of polymer science 2002年第3期20卷 197-203页

作者： Lan Huang Xiao-rong Hou Yuan-kang He Xiao-liang Zheng Fang Wei Xin-sheng Zhao Wei-xiao Cao college of chemistry & Molecular engineering peking university{3., China peking Univ Coll Chem & Mol Engn Beijing 100871 Peoples R China

An initial investigation on the roughness and frictional properties of the self-assembled thin films from polyelectrolytes is presented. Star-shaped C-60-Poly(styrene-maleic anhydride) was successful prepared. The multilayer thin films have been fabricated on mica with diazoresin as the cationic polyelectrolyte and hydrolyzed star-shaped C-60-poly(styrene-maleic anhydride) as the anionic polyelectrolyte via self-assembly technique. The crosslinking structure of the films is formed from the conversion of ionic bond to covalent bond after UV irradiation. AFM/FFM investigations provide insights into the roughness and frictional properties on a microscale. The roughness depends strongly on the number of film layers in the case of C-60-containing films. The frictional forces of the films exhibited a well behaved non-linear relationship in response to the change of applied load. It supports the prediction of enhanced load-bearing property Of C60-containing thin films.

关键词： star-shaped C-60-poly(styrene-maleic anhydride) self-assembly film AFM/FFM roughness frictional properties

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Synthesis and thermodynamic analysis of nano-La2O3

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Progress in Natural science:Materials International 2007年第7期17卷 838-844页

作者： Liu Lili~(1,2) Tang Jie~2 Li Yuxiang~1 Zhang Mei~(1**) Wang Xidong~(1,3. (1.department of Physical chemistry,university of {3. and Technology beijing,beijing 100083.China 2.National Institute for Materials {3.,Segen 1-2-1,Tsukuba 3.5-0047,Japan 3.college of engineering,beijing university,beijing 100871,China) [a]department of Physical chemistry University of Science and Technology Beijing Beijing China [b]National Institute Materials science Tsukuba Jpan [c]college of engineering Beijing University Beijing China

The thermodynamic parameters of La（NO3.3.nd La（OH）3.re evaluated and the thermodynamics of nano-La2O3.yn- thetic process is *** the base of thermodynamic analysis,La2O3.ano-powders are prepared by the sol-gel method and the experi- ment scheme is designed by an orthogonal *** dry-gelatin is analyzed with differential thermal analysis/thermo-gravimetric analy- sis（TGA-DTA）and X-ray diffraction *** microstructure of nano-La2O3.owders is observed by transmission dectron micro- *** synthetic parameters affecting the average grain size and dispersivity of nano-La2O3.articles are experimentally examined and *** the results indicate that nano-La2O3.articles well-dispersed are obtained and the average grain size is in the range of 20—50 nm.

关键词： nano-La2O3 sol-gel thermodynamic analysis

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On the Essential Self-Adjointness of Pseudodifferential Operators

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Acta Mathematica Sinica,English Series 1994年第1期10卷 72-79页

作者： Fan qihong department of Mathematics peking university {3.,100871 China 1. department of Mathematics Peking University 100871 Beijing China

In this paper we investigate the self-adjointness for a kind of pseudodifferential operators,which include the nonsemi-bounded Schr（o|¨）dinger operator,-△+v（x）,v（x）→-∞, as |x|→∞,and the relativistic correc... 详细信息

关键词： On the Essential Self-Adjointness of Pseudodifferential Operators

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Thermodynamic evaluation and hydrothermal preparation of K_xNa_(1-x)NbO_3

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Rare Metals 2008年第4期27卷 371-377页

作者： ZHANG Ci LV Haijun GUO Min ZHANG Mei WANG Xidong department of Physical chemistry University of Science and Technology Beijing Beijing 100083 China college of engineering. peking university Beijing 100871 China

The Gibbs free energies of reaction △rGτ of KNbO3.and NaNbO3.were calculated and then that of KxNa1-xNbO3.was estimated. On the basis of the thermodynamic calculation results, the hydrothermal temperatures were designed at 100, 160, and 23.℃ respectively. However, NaNbO3.was prepared when the heating temperature was higher than 160℃, and KNbO3.and KxNa1-xNbO3.were obtained at 23.℃, suggesting that only at a higher temperature the kinetic requirement is satisfied. According to the X-ray diffraction results, both the solid solutions, NaNbO3.based solid solution, Na1-xKxNbO3. and KNbO3.based solid solution, K1-xNaxNbO3. were hydrothermally synthesized in 6 mol/L alkali （NaOH and KOH） solution at 23.℃.

关键词： KNbO3 NaNbO3 thermodynamic calculation hydrothermal synthesis Gibbs free energy

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Syntheses, structures and magnetic properties of a family of one-dimensional M(Ⅱ)-lanthanide(Ⅲ) (M = Ni(Ⅱ) and Zn(Ⅱ)) coordination polymers

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science China chemistry 2007年第3期50卷 308-317页

作者： ZHANG Wen, ZHAO Fei, LIU Tao & GAO Song beijing National Laboratory for Molecular sciences, State Key Laboratory of Rare Earth Materials chemistry and Applications,{3. and Molecular engineering, peking university, beijing 100871, China 1. beijing National Laboratory for Molecular sciences State Key Laboratory of Rare Earth Materials Chemistry and Applications College of Chemistry and Molecular Engineering Peking University Beijing 100871 China

A series of 1D nickel(II)/zinc(II)-lanthanide(III) coordination polymers, [M(μ-L)2Ln(NO3.3.n·solvents (HL = bis(2-pyridylcarbonyl)amine; M = Ni, Ln = Gd (1·NiGd), Tb (2·NiTb), Dy (3.NiDy), Ho (4·NiHo), Y (5·NiY); M = Zn, Ln = Gd (6·ZnGd), Tb (7·ZnTb), Dy (8·ZnDy), Ho (9·ZnHo); solvents = H2O or H2O-ethanol), was synthesized and characterized. All of the complexes are isostructural at 293.K and crystallize in the orthorhombic space group Fddd. Magnetic measurements were performed on 1―9, where weak ferromagnetic interaction is found in 1·NiGd, ferromagnetic interaction in 2·NiTb and 3.NiDy, and antiferromagnetic interaction in 4·NiHo. A remarkable dc magnetic field dependence of ac susceptibilities was found in this series of complexes.

关键词： nickel lanthanide 3.-4f coordination polymer magnetic property

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Petrogenesis of Songshugou dunite body in the qinling orogenic belt, Central China: Constraints from geochemistry and melt inclusions

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science China Earth sciences 2005年第8期48卷 1146-1157页

作者： SU Li1,2, SONG Shuguang3.& ZHOU Dingwu1 1. Key Laboratory of Continental Dynamics of the Ministry of Education, department of Geology, Northwestern university, Xi’an 710069, China 2. The Geological Lab Center, China university of Geo{3.s (beijing), beijing 100083. China 3. Key Laboratory of Orogenic Belts of the Ministry of Education, department of Geology, peking university, beijing 100871, China 1. Key Laboratory of Continental Dynamics of the Ministry of Education Department of Geology Northwestern University 710069 Xi’an China 2. The Geological Lab Center China University of Geosciences 100083 (Beijing)Beijing China 3. Key Laboratory of Orogenic Belts of the Ministry of Education Department of Geology Peking University 100871 Beijing China

The Songshugou dunite body, which occupies an area of about 20 km2, is the largest ultramafic massif in the eastern qinling orogenic belt, Central China. The major compo-nent of this body is dunitic rocks including mylonitic dunite and coarse-grained dunite; they oc-cupy about 95 vol% of the total body. Petrography, mineral composition, major and trace ele-ments and primitive melt inclusions have been investigated in this paper; all revealed that this dunite body is the product of melt-rock interaction by porous percolation flow. In comparison with dunite sills or veins in harzburgite from the basal part of Oman ophiolite, this dunite body is characterized by lower contents of Al2O3. CaO and HREE but higher content of highly incom-patible elements and Zr and Hf. The LREE enriched patterns and primitive mantle normalized spidergrams of trace elements are also different from the Oman dunite. Combining with melt in-clusions observed in olivines, we conclude that this dunite body is the product of large- scale porous percolation flow of high-MgO melts within depleted mantle peridotites. The high-MgO magma, in essence, was most probably produced at the hot head of an upwelling mantle plume. The occurrence of the Songshugou dunite body is closely associated with the activity of mantle super-plume in Neo-Proterozoic era in the Yangtze Craton.

关键词： Songshugou dunite body, geochemistry, melt inclusion, mantle plume, qinling orogenic belt.

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Some preservation of stability of modules

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Chinese science Bulletin 1997年第19期42卷 1596-1599页

作者： WANG Hanpindepartment of Computer science and Technology. peking university,{3., China department of Computer science and Technology Peking University Beijing China

IN model theory, Zil’ ber has proved that any model of nontrivial -categorical theory is verysimilar to a module or field. So some people wanted to prove the famous Vaught’s conjec-ture for superstable theories of modules. Later, Buechler proved that the Vaught’s conjectureis true for the theories of modules with Morley rank 1. In order to reduce Vaught’s conjec-ture for superstablc theories of modules, Prest suggested discussing the preservation of stabili-ty--theory properties of modules when the underlying ring of the modules changes. Zieglergave some preservation theorems of clementary properties of the theory of modules in ref.

关键词： model theory ω-stahility superstability ring of fractions fractional module.

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