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Guided Waves in the Multilayered One-Dimensional Hexagonal Quasi-crystal Plates

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Acta Mechanica Solida Sinica 2021年第1期34卷 91-103页

作者： b.Zhang J.G.Yu x.M.Zhang x.H.Wang School of Mechanical and Power Engineering Henan Polytechnic UniversityJiaozuo454003China

Guided waves in the multilayered one-dimensional quasi-crystal plates are,respectively,investigated in the context of the bak and elasto-hydrodynamic *** curves and phonon and phason displacements are calculated using the Legendre polynomial *** characteristics in the context of these two models are analyzed in *** show that the phonon-phason coupling effects on the first two layers are the same at low frequencies;but,they are more significant on the first layer than those on the second layer at high *** obtained results lay the theoretical basis of guided-wave nondestructive test on multilayered quasi-crystal plates.

关键词： Multilayered structures Quasi-crystal plate Guided wave Phonon-phason coupling effect

A novel approach to enhance decrepitation temperature and reducibility of ultrafine iron ore concentrate pellets

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Journal of Iron and Steel Research International 2024年第11期31卷 2622-2632页

作者： b.L.Wen Z.H.Fan J.x.Li D.L.Liu J.L.yang School of Metallurgical Engineering Anhui University of TechnologyMa'anshan 243032AnhuiChina Jianlong(Liaoning)Energy Saving and Environmental Protection

Utilizing ultrafine iron ore concentrate for pellet production can expand domestic iron ore resources in China and promote the utilization of low-grade ***,a challenge arises with the low decrepitation temperature and reducibility in the preparation process of ultrafine iron ore concentrate *** address the challenge,a novel approach was proposed,which incorporated straw powder as an additive to enhance pellet porosity,thereby improving the decrepitation temper-ature and reducibility of ultrafine iron ore concentrate *** effect of varying proportions of straw powder(0.0-2.0%)on the characteristics of ultrafine iron ore concentrate pellets was *** indicate that at a 2.0%straw powder ratio,pellet decrepitation temperature notably rises from 380 to 540℃,while the reducibility index escalates from 25.7%to 48.1%.Nevertheless,the addition of straw powder results in diminished drop strength,compressive strength of green pellets,and cold crushing strength of fired *** addition,enhanced pellet reducibility leads to exacerbated reduction swelling index and reduction degradation *** these effects,all parameters remain within an acceptable range.

关键词： Ultrafine iron ore concentrate:Straw powder Green pellet quality Decrepitation temperature:Metallurgical property

A dissolution-diffusion sliding model for soft rock grains with hydro-mechanical effect

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Journal of Rock Mechanics and Geotechnical Engineering 2018年第3期10卷 457-467页

作者： Z.Liu C.Y.Zhou b.T.Li Y.Q.Lu x.yang Guangdong Engineering Research Center for Major Infrastructure Safety School of Civil Engineering Sun Yat-sen University

The deformation and failure of soft rock affected by hydro-mechanical（HM） effect are one of the most concerns in geotechnical engineering, which are basically attributed to the grain sliding of soft rock. This study tried to develop a dissolution-diffusion sliding model for the typical red bed soft rock in South China. based on hydration film, mineral dissolution and diffusion theory, and geochemical thermodynamics, a dissolution-diffusion sliding model with the HM effect was established to account for the sliding rate. Combined with the digital image processing technology, the relationship between the grain size of soft rock and the amplitude of sliding surface was presented. An equation for the strain rate of soft rocks under steady state was also derived. The reliability of the dissolution-diffusion sliding model was verified by triaxial creep tests on the soft rock with the HM coupling effect and by the relationship between the inversion average disjoining pressure and the average thickness of the hydration film. The results showed that the sliding rate of the soft rock grains was affected significantly by the waviness of sliding surface, the shear stress, and the average thickness of hydration film. The average grain size is essential for controlling the steady-state creep rate of soft rock. This study provides a new idea for investigating the deformation and failure of soft rock with the HM effect.

关键词： Soft rock Hydro-mechanical (HM) effect Mineral dissolution-diffusion Grain sliding model

(−)- and (+)-Securidanes A and b, Natural Triarylmethane Enantiomers: Structure and bioinspired Total Synthesis

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Research 2018年第1期2018卷 69-77页

作者： b.Zhou D.x.Liu x.J.Yuan J.Y.Li Y.C.xu J.Li YLi J.M.Yue State Key Laboratory of Drug Research Shanghai Institute of Materia MedicaChinese Academy of Sciences555 Zuchongzhi RoadShanghai 201203China State Key Laboratory of Applied Organic Chemistry College of Chemistry and Chemical EngineeringLanzhou UniversityLanzhou 730000China

Two pairs of enantiomers,(−)and(+)-securidanes A(1 and 2)and b(3 and 4)featuring unprecedented triarylmethane(TAM)skeletons,were isolated from Securidaca *** structures were established by spectroscopic data,x-ray crystallography,and CD analysis.A plausible biosynthetic pathway for 1−4 based on the co-isolated precursors was *** total synthesis of 1−4was completed in high yield,which in turn corroborated the biosynthetic *** 1−4 showed good inhibition against protein tyrosine phosphatase 1b(PTP1b).Te molecular docking demonstrated that the strongest inhibitor 3(IC50=7.52�M)reaches deeper into the binding pocket and has an additional H-bond.

关键词： methane skeleton synthesis

MEDIUM-RANGE ORDER CLUSTERS IN Fe-2.0%C ALLOY MELT

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Acta Metallurgica Sinica(English Letters) 2003年第6期16卷 513-518页

作者： x.b.Qin S.J.Cheng x.F.bian KeyLaboratoryofLiquidStructureandHeredityofMaterials MinistryofEducationShandongUniversityJi‘nan250061China MechanicalEngineeringDepartment ShandongUniversityofTechnologyZibo255000China

The structure of Fe-2.0%C alloy melt was investigated at 1580, 1560, 1540 and 1450℃ by using an x-ray diffractometer respectively. The results showed that with decreasing temperature, the average atoms of cluster, the coordination numbers, the correlation radius and the atom density increased, whereas the pre-peak of the structure factors curve remained almost at the same position. The appearance of the pre-peak indicated that the liquid structure and the solid structure of the Fe-2.0%C alloy were correlated.

关键词： liquid structure x-ray diffraction micro-inhomogeneous model,pre-peak structure factor

Strong and ductile Mg alloys developed by dislocation engineering

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Journal of Materials Science & Technology 2019年第3期35卷 394-395页

作者： M.Wang b.b.He M.x.Huang Department of Mechanical Engineering The University of Hong Kong Shenzhen Institute of Research and Innovation The University of Hong Kong

Dislocation engineering concept has been successfully employed to tackle the strength-ductility trade-off in steels, resulting in the development of high-strength high-ductility deformed and partitioned(D&P)steel. The present perspective proposes to employ such dislocation engineering concept to develop strong and ductile magnesium(Mg) alloys. High density of dislocations could be generated at appropriate temperature and retained in the Mg alloy after quenching to room temperature. Those dislocations inherited from the warm deformation could provide dislocation sources when the Mg alloy is deformed at room temperature, resulting in good ductility. The high dislocation density generated at warm deformation provides dislocation forest hardening, leading to improved yield strength of Mg alloy.

关键词： Dislocation engineering Mg alloys Warm rolling Strength and ductility

Context-free Grammars for Triangular Arrays

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Acta Mathematica Sinica,English Series 2015年第3期31卷 445-455页

作者： Robert x.J.HAO Larry x.W.WANG Harold R.L.yang Center for Combinatorics LPMC-TJKLC Nankai University

We consider context-free grammars of the form G = {f → f^b1＋b2＋1g^a1＋a2, g → f^b1 g^a1＋1},where ai and bi are integers sub ject to certain positivity conditions. Such a grammar G gives rise to triangular arrays {T（n, k）}0≤k≤n satisfying a three-term recurrence relation. Many combinatorial sequences can be generated in this way. Let Tn （x） =∑k=0^n T（n, k）x^k. based on the differential operator with respect to G, we define a sequence of linear operators Pn such that Tn＋1（x） = Pn（Tn（x））. Applying the characterization of real stability preserving linear operators on the multivariate polynomials due to borcea and br？ndén, we obtain a necessary and sufficient condition for the operator Pn to be real stability preserving for any n. As a consequence, we are led to a sufficient condition for the real-rootedness of the polynomials defined by certain triangular arrays, obtained by Wang and ***, as special cases we obtain grammars that lead to identities involving the Whitney numbers and the bessel numbers.

关键词： Context-free grammar stable polynomials real-rootedness bessel numbers Whitneynumbers

Nano-phase transformation of composite precipitates in multicomponent Al-Mg-Si(-Sc)alloys

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Journal of Materials Science & Technology 2022年第15期110卷 216-226页

作者： S.b.Wang C.F.Pan b.Wei x.Zheng Y.x.Lai J.H.Chen Key Laboratory of LCR Materials and Devices of Yunnan Province National Center for International Research on Photoelectric and Energy MaterialsSchool of Materials and EnergyYunnan UniversityKunming 650091China Collaborative Innovation Center of Renewable Energy Materials and Department of Physics Guangxi UniversityNanning 530004China Center for High-Resolution Electron Microscopy College of Materials Science and EngineeringHunan UniversityChangsha 410082China

Sc-addition can significantly enhance the performance of the micro-alloyed Al-Mg-Si-Sc ***,the mechanisms by which the Sc element modifies the microstructure of the alloys are still unknown in many ***,using atomic-scale transmission electron microscopy and atomic-resolution spectroscopy,we have revealed the microstructural differences between two age-hardened Al-0.5Mg-0.4Si(wt.%)alloys with and without *** first significant effect of Sc-addition on the precipitation microstructure of the Al-Mg-Si-Sc alloy is that Sc-atoms may distribute at theβ"-precipitate/Al-matrix interface and therefore accelerate aging kinetics at the initial stage of *** second significant effect of Sc-addition is that in the transition from theβ"-hardened peak-age stage to theβ′-hardened late stage,Sc-atoms can greatly improve the stability of transitionalβ"/b'/β′composite precipitates by entering the b'-substructures and/or locating at the precipitate/Al *** such Sc-atoms effectively suppressβ"toβ'transformation and cross-sectional coarsening of bothβ"and composite precipitates,leading to much finer precipitate needles with smaller diameter but much larger length,as compared with those precipitate needles formed in the alloy without ***,the alloy with Sc-addition exhibits a much better thermal stability than that without Sc.

关键词： Al alloy Strengthening mechanism Phase transition Transmission electron microscopy

REDUCTION bEHAVIOR OF IRON ORE PELLETS CONTAININGCARbON UNDER NON-ISOTHERMAL CONDITION

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Acta Metallurgica Sinica(English Letters) 2000年第5期13卷 1059-1067页

作者： x.M.yang Y.S.xie D.G.Wang D.b.Huang T.J.yang L.T.Kong Institute of Chemical Metallurgy The Chinese Academy of Sciences Beijing 100080China University of Science and Technology beijing Beijing 100083China

The reduction behavior of iron ore pellets containing carbon under non-isothermal condition in the temperature range from 573 to 1373 K was investigated in a laboratory scale setup. The test results show that carbon content has no obvious effect on reduction degree of composite pellets (C/O mole ratio=1.0) by CO in the temperature range from 573 to 1373 K under linear temperature-rising program; reduction degree of iron ore pellets containing carbon is large in 90%CO-10%CO2 mixture than that of in 100%CO atmosphere or in 80%CO-20%CO2 mixture; the s type temperature-rising program has a better effect than that of linear one in increasing the reduction degree; and reduction degree of slower linear temperature-rising program is greater than that of faster one, but the final reduction degrees, i.e., those at the highest temperature are about the same for various CO partial pressures or temperature-rising programs. The kinetic analysis also shows that the reduction of iron ore-carbon composite pellets by CO or CO-CO2 mixture under non-isothermal condition should be controlled by surface reaction, and the apparent reduction activation energy changes with the reduction progress under various test conditions.

关键词： iron ore pellet containing carbon reduction behavior kinetics activation energy non-isothermal