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Microstructure and hot ductility behavior of Ni-based superalloy U720Li with boron addition

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Rare Metals 2021年第5期40卷 1145-1154页

作者： Guang-Di Zhao fang Liu xi-Min Zang Wen-Ru Sun School of Material and Metallurgy University of Science and Technology LiaoningAnshan 114051China Institute of Metal Research Chinese Academy of SciencesShenyang 110016China

High-alloyed superalloy U720 Li is difficult to be processed through the conventional cast and wrought *** is an important strengthening element for superalloys,but the role of boron in the hot ductility of U720 Li alloy is not *** study is focused on the effect of boron addition,in the range of<0.0005 wt%-0.0240 wt%,on the microstructure and hot ductility behavior of superalloy U720 *** is found that boron addition significantly increases the content of eutectic(γ+γ’)and greatly affects the degree of continuity of the grain boundary eutectic(γ+γ’)*** addition dramatically worsens the 1100℃ tensile ductility of conventional cast U720 Li alloy and causes a change in tensile fracture mode from transgranular to *** eutectic(γ+γ’)represents the most effective site for crack *** deteriorates the hot ductility mainly by promoting the continuous precipitation of eutectic(γ+γ’)along the grain boundary.

关键词： Boron U720Li Eutectic(γ+γ’) Hot ductility Fracture mechanism

Microstructure and mechanical property of NbTaTiV refractory high-entropy alloy with different Y_(2)O_(3) contents

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Rare Metals 2022年第10期41卷 3504-3514页

作者： Tao Liao Yuan-kui Cao Wen-Min Guo Qi-Hong fang Jia Li Bin Liu State Key Laboratory of Powder Metallurgy Central South UniversityChangsha410083China State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan UniversityChangsha410082China

In this study,NbTaTiV refractory high-entropy alloys(RHEAs) reinforced with dispersed oxides were successfully designed and fabricated by mechanical alloying and subsequent spark plasma sintering(SPS).The effects of Y_(2)O_(3) content on the microstructure and mechanical properties have been systematically *** results show that the oxide dispersion strengthening(ODS) RHEAs are mainly composed of body centered cubic(BCC) matrix and multiscale oxides,including submicron Ti-(N,O) particles,nano-sized Y-Ti-O particles and nano-sized Y_(2)O_(3) *** ODS-RHEAs have excellent mechanical properties due to the multisc ale *** the content of Y_(2)O_(3) increasing from 1 wt% to 3 wt% Y_(2)O_(3),the compressive yield strength of the ODSRHEAs significantly increases from 1528 to 1866 MPa,while the fracture strain slightly reduces from 22% to 16%.The enhancement of the mechanical property is mainly attributed to the increased amount of multisc ale oxide particles and the refined grain structure.

关键词： Refractory high-entropy alloy Oxide dispersion strengthening Spark plasma sintering(SPS) Mechanical property Strengthening mechanism

Chemical passivation of methylammonium fragments eliminates traps,extends charge lifetimes,and restores structural stability of CH_(3)NH_(3)PbI_(3) perovskite

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Nano Research 2022年第5期15卷 4765-4772页

作者： xi Zhao Wei-Hai fang Run Long Oleg V.Prezhdo College of Chemistry Key Laboratory of Theoretical&Computational Photochemistry of Ministry of EducationBeijing Normal UniversityBeijing 100875China Department of Chemistry University of Southern CaliforniaLos AngelesCalifornia 90089USA

Hybrid organic-inorganic perovskites are currently considered the most promising next-generation photovoltaic ***,poor stability,arising from structural degradation under exposure to moisture,heat,and strong current,remains a critical challenge for their device *** ab initio nonadiabatic molecular dynamics,we demonstrate that methylamine fragments deriving from the dissociation of the methylammonium cation can undermine structural stability,produce deep hole traps,and decrease charge carrier lifetimes by 1-3 orders of *** stability and charge lifetime can be restored by methylamine passivation with chlorines,which withdraw electrons from the lone electron pair of methylamine and bring the trap levels down into the valence *** charge lifetime of the passivated system is even longer than that of the pristine *** simulations reveal the detailed microscopic mechanism underlying deterioration of perovskite performance due to molecular defects,and demonstrate an effective defect passivation strategy to obtain highly efficient and stable perovskite solar cells.

关键词： hybrid organic-inorganic perovskites structural stability methylammonium dissociation chlorine passivation time-domain density functional theory nonadiabati cmolecular dynamics

Preparation of poly（N-isopropylacrylamide） brush grafted silica particles via surface-initiated atom transfer radical polymerization used for aqueous chromatography

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Frontiers of Materials Science 2012年第1期6卷 60-68页

作者： Zong-Jian LIU Yan-Li LIANG fang-fang GENG fang LV Rong-Ji DAI Yu-kui ZHANG Yu-Lin DENG School of Life Science Beijing Institute of TechnologyBeijing 100081China Dalian Institute of Chemical Physics Chinese Academy of SciencesDalian 116023China

Thermoresponsive poly（N-isopropylacrylamide）（PNIPAAm） brushes were densely grafted onto silica surface via surface-initiated atom transfer radical polymeriza- tion （SI-ATRP）. The grafting reaction started from the surfaces of 2-bromoisobutyrate- functionalized silica particles in 2-propanol aqueous solution at ambient temperature using CuCIICuCI21N, N,N＇,N＇,N”.pentamethyldiethylenetriamine （PMDETA） as the catalytic system. Based on thermogravimetric analysis （TGA） results, the grafting amount and grafting density of PNIPAM chains on the surface of silica were calculated to be 1.29 mg/ m^2 and 0.0215 chains/nm^2, respectively. The gel permeation chromatography （GPC） result showed the relatively narrow molecular weight distribution （MwlMn= 1.21） of the grafted PNIPAAm. The modified silica particles were applied as high-performance liquid chromatography （HPLC） packing materials to successfully separate three aromatic compounds using water as mobile phase by changing column temperature. Temperature- dependent hydrophilic/hydrophobic property alteration of PNIPAAm brushes grafted on silica particles was determined with chromatographic interaction between stationary phase and analytes. Retention time was prolonged and resolution was improved with increasing temperature. Baseline separation with high resolution at relatively low temperatures was observed, demonstrating dense PNIPAAm brushes were grafted on silica surfaces.

关键词： poly(N-isopropylacrylamide) (PNIPAAm) atom transfer radical polymeriza-tion (ATRP) temperature-responsive chromatography separation

Stability and Collective Excitation of Two-Dimensional BECs with Two-and Three-Body Interactions in an Anharmonic Trap

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Communications in Theoretical Physics 2009年第3期51卷 433-440页

作者： YONG Wen-Mei WEI xiu-fang ZHOU xiao-Yan XUE Ju-kui College of Physics and Electronics Engineering Northwest Normal University Lanzhou 730070 China College of Science Gansu Agricultural University Lanzhou 730070 China Department of Physics Lanzhou City University Lanzhou 730070 China

The stability and collective excitation of Bose-Einstein condensates with both two- and three-body interactions in a two-dimensional anhaxmonic trap （i.e., harmonic plus quartic trap） are investigated. By using the variational method, the influence of the three-body interaction and the anharmonicity on the stability axe discussed in detail. It is found that the anhaxmonicity of the trap and the three-body interaction have significant effect on the stability and collective excitations of the system.

关键词： Bose Einstein condensates stability anharmonicity three-body interaction

A New Practical Approach for Procedurally Representing Lofted Surface

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计算机工程 1994年第S1期20卷 496-499页

作者： fang kui (National University of Defense Technology 410073)

Fitting a surface using geometric information (for example: an arbitrary set of 3D curves) is a useful method for comstructing complex surfaces. Tensor-product B-splines usually is used to constructe so-called lofted surfaces and most other types of surfaces in CAD, but several problems must be overcome if B-spline are to represent complex lofted surfaces[1]. We describe a practical approach by using an approximating Hermite type of surface, the construction of the surface is easy. Finally, a lofted surface model is given.

关键词： overcome approximating arbitrary spline CAGD parametric Bezier NURBS cubic offset

TRAF4 mediates activation of TGF-β signaling and is a biomarker for oncogenesis in breast cancer

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Science China(Life Sciences) 2014年第12期57卷 1172-1176页

作者： ZHOU fang fang LI fang xiE Feng ZHANG Zheng kui HUANG Hui Zhe ZHANG Long Life Sciences Institute Zhejiang University Department of Molecular Cell Biology Cancer Genomics Centre Netherlands and Centre for Biomedical Genetics Leiden University Medical Cente Faculty of Basic Medical Sciences Chongqing Medical University

The tumor-promoting arm of transforming growth factor beta(TGF-β)receptor signaling contributes to advanced cancer progression and is considered a master regulator of breast cancer *** mammals,there are six distinct members in the tumor-necrosis factor receptor(TNFR)-associated factor(TRAF)family(TRAF1–TRAF6),with the function of TRAF4 not being extensively studied in the past *** numerous studies have suggested that there is elevated TRAF4 expression in human cancer,it is still unknown in which oncogenic pathway TRAF4 is mainly *** review highlights TGF-β-induced SMAD-dependent signaling and non-SMAD signaling as the major pathways regulated by TRAF4 involved in breast cancer metastasis.

关键词： TRAF4 TGF-β breast cancer metastasis

Corrosion behavior of aluminum alloys in Na_2SO_4 solution using the scanning electrochemical microscopy technique

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International Journal of Minerals,Metallurgy and Materials 2009年第1期16卷 84-88页

作者： He-rong Zhou xiao-gang Li Chao-fang Dong kui xiao Tai Li School of Materials Science and Engineering University of Science and Technology Bei.jing Beijing 100083 China Beijing Key Laboratory for Corrosion Erosion and Surface Technology Beijing 100083 China

The corrosion behavior of aluminum alloys 1060 and 2A12 in a 10 mM Na2SO4＋5 mM KI solution was investigated by scanning electrochemical microscopy （SECM） and scanning electron microscopy （SEM）. The potential topography and corrosion morphology results show that the potential of the sample surface over the same area changes with the increase of immersion time. The corrosion area becomes large, and the potential becomes more negative. The corrosion potential of the 2A12 alloy surface is lower than that of 1060 aluminum, and 2A12 alloy becomes easily corrosive. This is the reason that preferential dissolution in the boundary region of some intermetallic particles （IMPs） occurs and different dissolution behaviors are associated with different types of IMPs because of different potentials.

关键词： aluminum alloys corrosion behavior intermetallic particles scanning electrochemical microscopy (SECM)

Monolithic Covalent Organic Framework Aerogels through Framework Crystallization Induced Self-assembly:Heading towards Framework Materials Synthesis over All Length Scales

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Chinese Journal of Polymer Science 2019年第11期37卷 1045-1052页

作者： Wei Zhao Tian-Pin Wang Jia-Li Wu Ru-Ping Pan xiang-Yang Liu xi-kui Liu College of Polymer Science and Engineering Sichuan University

Here, through the synergism between kinetic dynamic imine-exchange control and thermodynamic control, rarely observed compressible, porous, crystalline covalent organic framework (COF) aerogels were synthesized, the mechanism behind which is a framework crystallization induced self-assembly (FCISA) process. The prepared COF aerogel possessed extremely high BET surface over 2000 m^2·g^-1 and high maximum equilibrium adsorption capacity toward bisphenol-A of 699 mg·g^-1 in aqueous solution.

关键词： Covalent organic framework (COF) Aerogel Framework crystallization