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Science China(Technological Sciences) 2011年第12期54卷 3180-3190页

作者： GUO qiang sun YuWen GUO DongMing Key Laboratory for Precision and Non-Traditional Machining Technology of the Ministry of Education Dalian University of Technology Dalian 116024 China

The cutter runout effect has significant influence on the shape of cutter swept surface and the machining surface quality. Hence,it is necessary to integrate the cutter runout effect in cutter swept surface modeling,geometric error prediction and tool path optimization for five-axis flank machining. In this paper,an envelope surface model considering cutter runout effect is first established,and geometric errors induced by runout effect are derived based on the relative motion analysis between the cutter and part in machining. In the model,the cutter runout is defined by four parameters,including inclination angle,location angle,offset value and the length of cutter axis. Then the runout parameters are integrated into the rotation surface of each cutting edge that is used to form the final cutter envelope surface for the five-axis machining process. Thus,the final resulting geometric errors of the machined surface induced by cutter runout can be obtained through computing the deviations from the nominal cutter swept surface. To reduce these errors,an iterative least square method is used to optimize the tool paths for five-axis flank machining. Finally,a validation example is given for a specific ruled surface. Results show the effectiveness and feasibility of the analytical model of geometric errors induced by cutter runout,and also show that the geometric errors can be reduced significantly using the proposed tool path planning method.

关键词： cutter runout tool path optimization envelope surface five-axis machining geometric errors

Fractal dimension study of polaron effects in cylindrical GaAs/AlxGa1-xAs core-shell nanowires

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Frontiers of physics 2018年第2期13卷 159-165页

作者： Hui sun Hua Li qiang Tian Department of Physics Beijing Normal University Beijing 100875 China Department of Fundamentali Coursesl Academy of Armored Forces Engineering Beijing 100072 China

Polaron effects in cylindrical GaAs/AlxGa1-xAs core-shell nanowires are studied by applying the fractal dimension method. In this paper, the polaron properties of GaAs/AlxGa1-xAs core-shell nanowires with different core radii and aluminum concentrations are discussed. The polaron binding energy, polaron mass shift, and fractal dimension parameter are numerically determined as functions of shell width. The calculation results reveal that the binding energy and mass shift of the polaron first increase and then decrease as the shell width increases. A maximum value appears at a certain shell width for different aluminum concentrations and a given core radius. By using the fractal dimension method, polaron problems in cylindrical GaAs/AlxGa1-xAs core-shell nanowires are solved in a simple manner that avoids complex and lengthy calculations.

关键词： core-shell nanowire polaron effects fractal dimension method

Preparation of Dicarboxyl Cellulose Nanocrystals from Agricultural Wastes by Sequential Periodate-Chlorite Oxidation

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Journal of Renewable Materials 2020年第4期8卷 447-460页

作者： Xiaozheng sun qiang He Yu Yang College of Engineering Northeast Agricultural UniversityHarbin150030China

Agricultural waste straw is the renewable resource with the highest annual yield in the *** value-added applications of agricultural waste,dicarboxyl cellulose nanocrystals(DCCs)are prepared from rice,wheat,and corn straw by sequential periodate-chlorite *** this study,DCCs from rice,wheat,and corn straw were characterized by transmission electron microscopy(TEM),Fourier transform infrared spectrometer,X-ray diffractometer(XRD),and thermal gravimetric analysis(TGA).The carboxyl content of the DCCs was also *** results show that the crystallinity index decreased after sequential periodate-chlorite oxidation;however,the cellulose I structure was *** results show that rod-shaped DCCs with an average length and width of 287.0 nm and 9.9 nm,respectively,were successfully prepared by sequential periodate-chlorite *** carboxyl content of the DCCs was around 3.9 mmol/g,and not affected by the type of *** to study the removal of copper ions in aqueous medium were performed with the prepared *** adsorption capacities of copper ions were 131,162,and 144 mg/g for DCCs prepared from rice,wheat,and corn straws,*** results show that DCCs prepared from rice,wheat,and corn straws by sequential periodatechlorite oxidation have potential for the removal of copper ions from aqueous medium.

关键词： Agricultural waste dicarboxyl cellulose nanocrystals sequential periodate-chlorite oxidation copper ion removal

Combined torsional buckling of double-walled carbon nanotubes with axial load in the multi-field coupled condition

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Science China(Physics,Mechanics & Astronomy) 2011年第9期54卷 1659-1665页

作者： sun YuGang YAO XiaoHu HAN qiang Department of Engineering Mechanics School of Civil Engineering and Transportation South China University of Technology Guangzhou 510640 China

The present study has theoretically investigated the combined torsional buckling of double-walled carbon nanotubes (DWCNTs) with axial load in the multi-field coupled condition. The effects of torsion, axial load, thermal-electrical change, surrounding elastic medium and the Van der Waals forces are all taken into consideration. The governing equation of buckling for CNTs subjected to thermo-electro-mechanical loadings has been established based on an elastic shell model of continuum mechanics. Reasonable simplifications are made to get the explicit expression of the critical buckling shear stress of DWCNTs, and numerical experiments are conducted for further research. It is shown that under certain electric and temperature field the critical buckling shear stress of DWCNTs only depends on the wave number of buckling modes. On the other hand, all the related impact factors have enormous influence on the critical buckling shear stress under a certain buckling mode. The critical buckling shear stress changes linearly with the axial-to-shear stress ratio, as well as the thermal and electric change. Axial compression tends to make DWCNTs unstable, while axial tension benefits the buckling stability. The critical buckling shear stress is directly proportional to the applied voltage. At room or lower temperature, the critical shear stress for infinitesimal buckling increases as the temperature change increases, while it decreases at a higher temperature. The conclusions are useful for the design of nano-structures related to the buckling stability of DWCNTs.

关键词： Carbon nanotubes buckling multi-field coupling

Asymmetric Michael addition reactions catalyzed by a novel upper-rim functionalized calix[4]squaramide organocatalyst

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Chinese Chemical Letters 2020年第12期31卷 3259-3262页

作者： Ke Yang Zhiyan Ma hong-Xiao Tong Xiao-qiang sun Xiao-Yu Hu Zheng-Yi Li Jingsu Key Laboratory of Advanced Catalytic Materials&Technology School of Petrochemical EnginerngChangzhou LniversityChangzhou 213184China College of Material Science and Technology Nanjing University of Aeronatutics and AstronauricsNanjing 211100China

A novel upper-rim functionalized calix[4]squaramide organocatalyst bearing bis-squaramide and cyclohexanediamine scaffolds was designed and prepared to catalyse a serial of asymmetric Michael addition of 1,3-dicarbo nyl compounds to a,β-unsaturated carbonyl compounds in high yields(up to 99%)and good to excellent enantiomeric excesses(up to 99%ee).The comparative experiments indicated that the cooperative effect between calixarenes cavitives and chiral catalytic centers on this calix[4]squaramide catalyst could promote these ***,this strategy also provides valuable and easy access to chiral chromene,naphthoquinone and acetylacetone derivatives,which are important skeletons in biological and pharmaceutical compounds.

关键词： Calixsquaramide Supramolecular catalyst Asymmetric catalysis Michael addition Organic synthesis

Antibacterial ability and cytocompatibility of Cu-incorporated Ni–Ti–O nanopores on NiTi alloy

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Rare Metals 2019年第6期38卷 552-560页

作者： Jia-Ming Zhang Yong-Hua sun Ya Zhao Yan-Lian Liu Xiao-hong Yao Bin Tang Rui-qiang Hang Research Institute of Surface Engineering College of Materials Science and Technology Taiyuan University of Technology

Nearly equiatomic nickel–titanium(NiTi) alloy is an ideal implant biomaterial because of its shape memory effect, superelasticity, low elastic modulus as well as other desirable ***, it is prone to infection because of its poor antibacterial *** present work incorporated Cu into Ni–Ti–O nanopores(NP–Cu) anodically grown on the NiTi alloy to enhance its antibacterial ability, which was realized through *** results show that incorporation of Cu(0.78 at%–2.37 at%)has little influence on the NP diameter, length and *** release level of Cu ions is in line with loadage which may be responsible for the improved antibacterial ability of the NiTi alloy to combat possible bacterial infection in ***, the NP–Cu shows better cytocompatibility and even can promote proliferation of bone marrow mesenchymal stem cells(BMSCs),up-regulate collagen secretion and extracellular matrix mineralization when compared with Cu-free *** antibacterial ability and cytocompatibility of the NP–Cu render them to be promising when serving as NiTi implant coatings.

关键词： Nickel–titanium alloy Nickel–titanium–oxygen nanopores Copper Antibacterial ability Cytocompatibility

Theoretical Research and Experimental Validation of Elastic Dynamic Load Spectra on Bogie Frame of High-speed Train

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Chinese Journal of Mechanical Engineering 2016年第3期29卷 498-506页

作者： ZHU Ning sun Shouguang LI qiang ZOU Hua Engineering Research Center of Structure Reliability and Operation Measurement Technology of Rail Guided Vehicles Ministry of Education Beijing Jiaotong University

When a train runs at high speeds, the external exciting frequencies approach the natural frequencies of bogie critical components, thereby inducing strong elastic vibrations. The present international reliability test evaluation standard and design criteria of bogie frames are all based on the quasi-static deformation hypothesis. Structural fatigue damage generated by structural elastic vibrations has not yet been included. In this paper, theoretical research and experimental validation are done on elastic dynamic load spectra on bogie frame of high-speed train. The construction of the load series that correspond to elastic dynamic deformation modes is studied. The simplified form of the load series is obtained. A theory of simplified dynamic load–time histories is then deduced. Measured data from the Beijing–Shanghai Dedicated Passenger Line are introduced to derive the simplified dynamic load–time histories. The simplified dynamic discrete load spectra of bogie frame are established. Based on the damage consistency criterion and a genetic algorithm, damage consistency calibration of the simplified dynamic load spectra is finally performed. The computed result proves that the simplified load series is reasonable. The calibrated damage that corresponds to the elastic dynamic discrete load spectra can cover the actual damage at the operating conditions. The calibrated damage satisfies the safety requirement of damage consistency criterion for bogie frame. This research is helpful for investigating the standardized load spectra of bogie frame of high-speed train.

关键词： elastic dynamic load spectra finite element method modal deformation calibration bogie frame high-speed train

Redesigned Surface Based Machining Strategy and Method in Peripheral Milling of Thin-walled Parts

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Chinese Journal of Mechanical Engineering 2010年第3期23卷 282-287页

作者： JIA Zhenyuan GUO qiang sun Yuwen GUO Dongming Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education Dalian University of Technology Dalian 116024 China

Currently, simultaneously ensuring the machining accuracy and efficiency of thin-walled structures especially high performance parts still remains a challenge. Existing compensating methods are mainly focusing on 3-aixs machining, which sometimes only take one given point as the compensative point at each given cutter location. This paper presents a redesigned surface based machining strategy for peripheral milling of thin-walled parts. Based on an improved cutting force/heat model and finite element method（FEM） simulation environment, a deflection error prediction model, which takes sequence of cutter contact lines as compensation targets, is established. And an iterative algorithm is presented to determine feasible cutter axis positions. The final redesigned surface is subsequently generated by skinning all discrete cutter axis vectors after compensating by using the proposed algorithm. The proposed machining strategy incorporates the thermo-mechanical coupled effect in deflection prediction, and is also validated with flank milling experiment by using five-axis machine tool. At the same time, the deformation error is detected by using three-coordinate measuring machine. Error prediction values and experimental results indicate that they have a good consistency and the proposed approach is able to significantly reduce the dimension error under the same machining conditions compared with conventional methods. The proposed machining strategy has potential in high-efficiency precision machining of thin-walled parts.

关键词： redesigned surface tool path part deflection error prediction finite element method

Enhancing both strength and toughness of carbon/carbon composites by heat-treated interface modification

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Journal of Materials Science & Technology 2019年第3期35卷 383-393页

作者： Jiajia sun Hejun Li Liyuan Han qiang Song State Key Laboratory of Solidification Processing Northwestern Polytechnical University

A simple method to increase both strength and toughness of carbon/carbon(C/C) composites is *** method is based on the heat treatment of the pre-deposited thin carbon coating, leading to the formation of more orderly pyrolytic carbon(PyC) as a functional interlayer between fiber and matrix that could optimize the interfacial sliding strength in C/C composites. Effects of such a heat-treated PyC layers on the microstructure, tensile strength and fracture behavior of unidirectional C/C composites were investigated. Results showed that although the in-situ fiber strength was deteriorated after the introduction of interfacial layer, tensile strength of the specimen was greatly improved by 38.5% compared with pure C/C composites without any treatment. The interfacial sliding stress sharply decreased, which was interpreted from finite element analysis and verified by Raman spectra. Therefore, the fracture behavior was changed from brittle fracture to multiple-matrix cracking induced non-linear mechanical ***, the ultimate strength can be predicted by different models according to the interfacial sliding stress. Our research would provide a meaningful way to improve both strength and toughness of C/C composites.

关键词： Carbon/carbon composites Tensile strength Interface Heat treatment

RHEOLOGICAL PROPERTIES OF WHEAT GLIADINS IN AQUEOUS PROPANOL

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Chinese Journal of Polymer Science 2013年第5期31卷 809-814页

作者： Shao-min sun 宋义虎 qiang Zheng MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and EngineeringZhejiang University

Rheological properties of wheat gliadins in 50% （V/F） aqueous propanol were carried out as a function of gliadin concentration c and temperature. The solutions at 20 g L-1 to 200 g L-1 behave as Newtonian fluids with an flow activation energy of 23.5-27.3 kJ mol-1. Intrinsic viscosity [η] and Huggins constant kH are determined according to Huggins plot at c 〈 120 g L-1. The results reveal that gliadins are not spherical shaped and the molecular size tends to increase with temperature due to improved solvation.

关键词： Gliadin Solution Rheological properties Intrinsic viscosity.