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Isothermal oxidation behavior of Nb-bearing austenitic cast steels at 950℃

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International Journal of Minerals,Metallurgy and Materials 2022年第4期29卷 814-824页

作者： Hailong Zhao Longfei Li qiang feng Beijing Advanced Innovation Center for Materials Genome Engineering State Key Laboratory for Advanced Metals and MaterialsUniversity of Science and Technology BeijingBeijing 100083China

The oxidation behaviors of three austenitic cast steels with different morphologies of primary carbides at 950℃ in air were investigated using scanning electron microscopy,energy dispersive spectroscopy,and focused ion beam/transmission electron *** oxidation kinetics followed a logarithmic law,and the oxidation rate can be significantly decreased as long as a continuous silica layer formed at the scale/substrate *** the local Si concentration was inadequate,internal oxidation occurred beneath the oxide *** spallation of oxides during cooling can be inhibited with the formation of internal oxidation,owing to the reduced mismatch stress between the oxide scale and the ***“Chinese-script”primary Nb(C,N)was superior to the dispersed primary Nb(C,N)in suppressing the oxidation penetration in the interdendritic region by supplying a high density of quick-diffusion Cr *** addition,the innermost and outermost oxidation layers were enriched with Cr,whereas the Cr evaporation in the outermost layer was significant when the water vapor concentration in the environment was high *** findings further the understanding regarding the oxidation behavior of austenitic cast steels and will promote the alloy development for exhaust components.

关键词： austenitic cast steels isothermal oxidation primary Nb(C,N) internal oxidation Cr depletion

Analytical solution for stress and deformation of the mining floor based on integral transform

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International Journal of Mining Science and Technology 2015年第4期25卷 581-586页

作者： feng qiang Jiang Binsong State Key Laboratory of Geomechanics and Deep Underground Engineering China University of Mining & Technology Civil Engineering and Architecture Shandong Key Laboratory of Civil Engineering Disaster Prevention & Mitigation Shandong University of Science and Technology

Following exploitation of a coal seam, the final stress field is the sum of in situ stress field and an excavation stress field. Based on this feature, we firstly established a mechanics analytical model of the mining floor strata. Then the study applied Fourier integral transform to solve a biharmonic equation,obtaining the analytical solution of the stress and displacement of the mining floor. Additionally, this investigation used the Mohr–Coulomb yield criterion to determine the plastic failure depth of the floor strata. The calculation process showed that the plastic failure depth of the floor and floor heave are related to the mining width, burial depth and physical–mechanical properties. The results from an example show that the curve of the plastic failure depth of the mining floor is characterized by a funnel shape and the maximum failure depth generates in the middle of mining floor; and that the maximum and minimum principal stresses change distinctly in the shallow layer and tend to a fixed value with an increase in depth. Based on the displacement results, the maximum floor heave appears in the middle of the stope and its value is 0.107 m. This will provide a basis for floor control. Lastly, we have verified the analytical results using FLAC3 Dto simulate floor excavation and find that there is some deviation between the two results, but their overall tendency is consistent which illustrates that the analysis method can well solve the stress and displacement of the floor.

关键词： Integral transform Mining floor Plastic failure depth Floor heave Analytical solution

A multi-agent based intelligent configuration method for aircraft fleet maintenance personnel

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Chinese Journal of Aeronautics 2014年第2期27卷 280-290页

作者： feng qiang Li Songjie Sun Bo School of Reliability and Systems Engineering Beihang University

A multi-agent based fleet maintenance personnel configuration method is proposed to solve the mission oriented aircraft fleet maintenance personnel configuration problem. The mainte- nance process of an aircraft fleet is analyzed first. In the process each aircraft contains multiple parts, and different parts are repaired by personnel with different majors and levels. The factors and their relationship involved in the process of maintenance are analyzed and discussed. Then the whole maintenance process is described as a 3-layer multi-agent system （MAS） model. A com- munication and reasoning strategy among the agents is put forward. A fleet maintenance personnel configuration algorithm is proposed based on contract net protocol （CNP）. Finally, a fleet of 10 aircraft is studied for verification purposes. A mission type with 3 waves of continuous dispatch is imaged. Compared with the traditional methods that can just provide configuration results, the proposed method can provide optimal maintenance strategies as well.

关键词： Aircraft Configuration Fleet Maintenance-planningMulti-agent system Personnel

Fractal-like Kinetic Characteristics of Coalbed Methane Hydrate Dissociation at Normal Pressure

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Chinese Journal of Chemistry 2011年第1期29卷 21-26页

作者： Xu, feng Wu, qiang Zhu, Lihua School of Safety Engineering & Technology Heilongjiang Institute of Science & Technology Harbin Heilongjiang 150027 China

Surface modality of coalbed methane hydrate and fractal-like kinetic characteristics of the hydrate dissociation at normal pressure have been studied by using fractal geometry theory. The results show that the surface modality of coalbed methane hydrate has fractal characteristic, and the dissociation kinetics of coalbed methane hydrate is fractal-like. Moreover, a new kinetic model for coalbed methane hydrate dissociation was proposed, and its reliability was validated.

关键词： coalbed methane hydrate dissociation kinetic normal pressure fractal

The Fine Structures of Three Symmetric Latin Squares with Even Orders

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Acta Mathematica Sinica,English Series 2011年第6期27卷 1137-1148页

作者： Er qiang feng Yan Xun CHANG Institute of Mathematics Beijing Jiaotong University Beijing 100044 P. R. China

Denote by SFin（v） the set of all integer pairs （t, s） for which there exist three symmetric Latin squares of order v on the same set having fine structure （t, s）. We completely determine the set SFin（2n） for a... 详细信息

关键词： Symmetric Latin square symmetric Latin trade fine structure

Enhancing gene editing efficiency for cells by CRISPR/Cas9 system-loaded multilayered nanoparticles assembled via microfluidics

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Chinese Journal of Chemical Engineering 2021年第10期34卷 216-220页

作者： Xuanyu Li qiang feng Ziwei Han Xingyu Jiang Shenzhen Bay Laboratory Department of Biomedical EngineeringSouthern University of Science and TechnologyShenzhen 518055China

Most non-viral carriers for in vitro delivery of nucleic acids suffer from low efficiency of introducing m RNA and other nucleic acids,especially large m ***9 protein is the nuclease part of the powerful gene-editing tool,CRISPR/Cas9 system,Cas9 m RNA is particularly large,thus presents a big challenge for *** assembled a multilayered biodegradable nanocarrier to load Cas9 m RNA inside to protect Cas9 m RNA from *** used a microfluidic chip to synthesize a small,positively charged,and degradable core to attract negatively charged Cas9 m *** microfluidic assembly allows the core to be small enough to incorporate into a cationic *** multilayered nanocarriers elevated the delivery efficiency of Cas9 m RNA by over 2 folds and increased the expression by over 5 folds compared to commercially used non-viral *** addition,the multilayered nanocarriers do not require reduced serum medium for *** using the standard complete medium for transfection,the multilayered nanocarriers could increase the expression of Cas9 m RNA by over 15 folds compared to commercially used non-viral *** co-delivery of Cas9 m RNA and sg RNA via LRC elevated the gene-editing efficiency by 3 folds compared to that via commercially used non-viral *** on the higher transfection efficiency of Cas9 m RNA/sg RNA than commercially used non-viral carriers,these multilayered nanocarriers may have a good prospect as efficient commercial delivery carriers for Cas9 m RNA/sg RNA and other nucleic acids.

关键词： Nanotechnology Biomedical engineering Microfluidics CRISPR/Cas9 system Poly(lactic-co-glycolic acid)

Synthesis of 1,1'-binaphthyl-2,2'-diamine from 2-naphthol under atmospheric pressure

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Chinese Chemical Letters 2009年第10期20卷 1150-1152页

作者： qiang feng Chao Zhang qiang Tang Mei Ming Luo Key Laboratory of Green Chemistry & Technology of Ministry of Education College of Chemistry Sichuan University Chengdu 610064 China

A practical protocol to obtain 1,1′-binaphthyl-2,2′-diamine was developed from 2-naphthol and 2-naphthylhydrazine under mild conditions： solvent-free, 125-130 ℃, atmospheric pressure. The convenient procedure make... 详细信息

关键词： 1,1′-Binaphthyl-2,2′-diamine 2-Naphthol 2-Naphthylhydrazine Synthesis

The stable planar conformation of the γ-butyrolactone ring in solution

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Chinese Chemical Letters 2010年第2期21卷 187-190页

作者： Zhi qiang feng Cheng Lie Yin Institute of Materia Medica Chinese Academy of Medical Sciences Beijing 100050 China Department of Chemistry Beijing Normal University Beijing 100875 China

The conformations ofγ-butyrolactone ring in solution were deduced on the basis of ~1H NMR spectra of geminal protons of the butyrolactone ring.A series of optically pure(Z)-(-)-4-(1 -alkoxyl-1 -carbalkoxy-methylene)-... 详细信息

关键词： β-Methylene-γ-butyrolactone Planar conformation Envelope conformation

Syntheses,Structure and Thermal Analysis of a Cobalt Coordination Polymer with Multiform Helical Features Based on Flexible Iododicarboxylate Ligand and N-donor Ancillary Ligand

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Chinese Journal of Structural Chemistry 2015年第5期34卷 735-740页

作者： LI Bo FAN Hui-Tao WANG Zhi-qiang feng Chao-qiang College of Chemistry and Pharmaceutical Engineering Nanyang Normal University

A new 3D complex,[Co（L）（bpe）0.5（H2O）2]n（1,H2 L = 5-iodo-benzene-1,3-dioxyacetic acid,bpe = 1,2-bis（4-pyridyl）ethylene）,has been hydrothermally synthesized and structurally characterized by elemental analysis,IR and X-ray *** is formulated as C16H16 Co INO8,crystallizes in monoclinic,space group P21/c,with a = 9.806（2）,b = 6.5492（13）,c = 28.187（8） A,β = 100.12（3）°,V = 1782.0（7） A^3,Z = 4,Dc = 1.998 g/m^3,F（000） = 1052,Μr = 536.13,the final R = 0.0393 and w R = 0.0858 for 3134 observed reflections with I 〉 2σ（I）.Complex 1 displays a 3D framework with multiform helical features,left-and right-handed triple helical braids and single helical chains,which can be simplified as a new type of（3,4）-connected lattice with a（6·10^2）（6^2·10^4） SchlAfli ***,the thermal analysis of complex 1 has also been investigated.

关键词： coordination polymer triple helical braid topology