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Wang L.,Jilin University | Ren F.,Changchun Normal University | Li K.K.,China South Industries Group Corporation
MATEC Web of Conferences | Year: 2016

Smooth shift and low shift shock are needed to improve power shift quality and comfort of construction vehicle. And higher dynamic performance of power shift clutch is needed. In this paper, the dynamic mathematical model and simulation model of the clutch engagement process were established, the factors affecting the shift quality were analyzed qualitatively and quantitatively. The simulation model of the transmission system was established based on the software AMESim, the corresponding vehicle tests were performed, and the shifting quality was improved by changing key parameters. Analysis results illustrate that the proposed mathematical model and simulation model are correct and effective and can be used to predict and evaluate construction vehicle shift-feel, which are the theoretical basis for analysis and research on the static and dynamic characteristics of the dynamic shifting process in the future. © 2016 The Authors, published by EDP Sciences.


Zhao Y.,Beihang University | Li J.-P.,Aerospace Research Institute of Materials And Processing Technology | Wang T.-Y.,Beihang University | Li R.-X.,Beihang University | And 2 more authors.
Wuji Cailiao Xuebao/Journal of Inorganic Materials | Year: 2016

ZrB2 nanoparticles were synthesized synergistically by Sol-Gel method and carbothermal reduction reaction using zirconium n-propoxide, acetic acid, boric acid and xylitol as starting materials. In the reaction system, xylitol acted as a carbon source for the carbothermal reduction reaction and chelated boron, leading to the formation of coordination compound through its polyhydroxy reaction with boric acid. According to the Fourier Transform infrared spectra and thermal analysis of gel precursor, the effects of sol and gel reaction processes on the carbothermal reduction reaction temperature and gelation time were discussed. The results show that the polyhydroxy compound of xylitol is beneficial to initiate reactions and gelation, which makes the threshold throughout the whole chemical processes easy to overcome. The gel does not need aging treatment and the reaction temperature is lowered. Besides, a single phase of equiaxed ZrB2 nanoparticles could be obtained from nascent state gel calcined at 1450℃ with n(xylitol)/n(zirconium n-propoxide) of 1.4. The average diameter and oxygen content of ZrB2 nanoparticles are ca. 50 nm and 1.36wt%, respectively. © 2016, Science Press. All right reserved.


Wang T.,Beihang University | Xiong Y.,Beihang University | Li R.,Beihang University | Cai H.,China South Industries Group Corporation
New Journal of Chemistry | Year: 2016

A series of molybdenum-doped tungsten bronzes with various alkali metals were synthesized by a solvothermal process using ethanol and acetic acid as solvents. All the X-ray diffraction (XRD) peaks for the samples could be indexed as the corresponding types of hexagonal tungsten bronzes with the general formula, MxWO3, where M denotes an alkali metal. Targeted research on cesium tungsten bronze indicates that the actual atomic ratio of Cs to W (x) could be influenced by the introduction of molybdenum, which has a critical effect on the infrared absorption properties. Optical tests show that molybdenum-doping is an effective process, with respect to enhancing the absorption of infrared and the conversion efficiency of light energy to heat energy, for tungsten bronzes with various alkali metals. The optimum starting Mo/W (mol) ratios for obtaining high infrared absorption properties were 0.01 for sodium and potassium tungsten bronzes and 0.03 for rubidium and cesium tungsten bronzes. Among the samples, doped cesium tungsten bronze has the strongest properties. © 2016 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.


Yang B.-Y.,Beihang University | Li J.-P.,Aerospace Research Institute of Materials And Processing Technology | Wang T.-Y.,Beihang University | Li R.-X.,Beihang University | And 2 more authors.
Wuji Cailiao Xuebao/Journal of Inorganic Materials | Year: 2014

ZrB2 particles were synthesized by a Sol-Gel method using zirconium n-propoxide, boric acid, acetic acid and D-fructose. D-Fructose acts as both a modifier and a carbon source for carbothermal reduction reaction. For comparison, both nascent state gel and aged gel were used to clarify the aging-time-dependent mechanism for ZrB2 synthesis. As a result, a single phase ZrB2 powder with a uniform size and shape distribution can be obtained from the aged gel with a boron and carbon to zirconium molar ratio of 3.5-4 and 7, respectively, after reduced at 1550°C for 2 h. Besides, the synthesized ZrB2 particles exhibit prism-like morphology with average particle size of ca. 4-7 μm in length, 1 μm in diameter of excircle of the cross-section and 4-7 in aspect ratio, when initial raw materials ratio n(B)/n(Zr) is 3.5-4 and n(C)/n(Zr) is 7. The median diameter D50 is 6.46 μm and specific surface area is about 2.53 m2/g. Furthermore, a complete carbothermal reduction of ZrO2 can be achieved using the aged gel.


Zhang S.,Beihang University | Xu Y.,Beihang University | Wang T.,Beihang University | Li R.,Beihang University | Cai H.,China South Industries Group Corporation
Jinshu Xuebao/Acta Metallurgica Sinica | Year: 2016

CeO2 is an important rare earth oxide and can be used in automotive exhaust three-way catalysts on the basis of its oxygen storage capability. Ion doping is an effective method to enhance the oxygen storage capability of CeO2. And when doping a cation whose size is smaller than Ce4+ and valence is lower than +4, it tends to evolve more defects. It is known that defects play important roles in enhancing the oxygen storage capability of CeO2. Therefore, In ion was selected as a dopant cation which matches above two factors of size and valence. In this work, a series of CeO2 with different content of In3+ were synthesized via a two-step process. The precursor was synthesized by a solvothermal method at 200℃ using a mixture solvent of (CH2OH)2 and H2O, as well as Ce(NO3)3·6H2O and In(NO3)3·4.5H2O as Ce and In sources, respectively. CeO2 was obtained after the precursor was calcined at 500℃ for 2 h in air. It was found that the solid solubility of In3+ in CeO2 was 1% (molar fraction). The doping of 1%In3+ in CeO2 almost had no impact on the morphology of multilayered structure. However, a second phase of small particles appeared and there were some changes of the morphology of multilayered structure when the concentration of In3+ increased further. The specific surface area of the 1%In3+ solid solution was 100 m2/g, which was th highest among all the samples, and undoped CeO2 (92 m2/g) ranked second. When the content of In3+ was above the solid solubility,i.e., 1%In3+, the specific surface area decreased. The low temperature oxygen storage capability could be improved from 3.6×10-4 mol/g for undoped CeO2 to 4.4×10-4 mol/g for 1%In3+-doped CeO2. When the In3+ content was greater than or equal to 3%, the low temperature oxygen storage capability decreased at the beginning, and then almost no change. Lattice parameter decreased and the concentration of Ce3+ and oxygen vacancy increased by the doping of In3+. Moreover, lattice parameter, the specific surface area, concentration of oxygen vacancy and low temperature oxygen storage capacity could mark a turning point for 1%In3+. It could be found that the low temperature oxygen storage capability was in relation to both the specific surface area and the concentration of oxygen vacancy of CeO2. In addition, the low temperature reduction peaks shifted towards lower temperatures with the addition of In3+. © All right reserved.


Xu Y.-X.,Beijing Institute of Technology | Wang S.-S.,Beijing Institute of Technology | Zhu X.-Q.,China South Industries Group Corporation
ICCASM 2010 - 2010 International Conference on Computer Application and System Modeling, Proceedings | Year: 2010

In the present study, a lot of numerical analysis and experiments were performed to investigate the penetration power of jet under great standoff distance. In the Numerical simulation, the finite element model was built based on the representative shaped charge. Through computation on nonlinear dynamics AutoDyn program, the penetration characteristics that jet shaped by representative charge impact on the semi-infinite steel target and interval plates under different standoff was obtained; base on these, under the same condition, the static explosive experiments that the jet impact on the interval plates under different standoffs were done, the variety rule between the standoff and layer number penetrated by jet was obtained. The outcomes between experiments and numerical simulation were consistent. It was indicated that the numerical simulation method was correct and available. © 2010 IEEE.


Wang J.-G.,Nanjing University of Science and Technology | Wang J.-G.,China South Industries Group Corporation | Yu Y.-G.,Nanjing University of Science and Technology | Guo F.,China South Industries Group Corporation | Zhou L.-L.,Nanjing University of Science and Technology
Dandao Xuebao/Journal of Ballistics | Year: 2015

To provide theoretical foundation for interior ballistic design of cased telescoped ammunition (CTA) gun, the influence of loading parameters variation of CTA gun on the interior ballistic process was studied. Based on the second ignition and combustion control technology of gunpowder, the properties experiments of interior ballistics of 35 mm CTA gun were carried out, and the interior ballistic theoretical model of second ignition was established. The calculated result is in good agreement with the experimental result. On this basis, the effects of multi-parameters including main charge loading dose, projectile mass, chamber volume and gunpowder force on the interior ballistic properties of CTA gun were analyzed. The results offer valuable reference for the design of interior ballistics of CTA gun. ©, 2015, Nanjing University of Science and Technology. All right reserved.


Fu X.,Nanjing University of Aeronautics and Astronautics | Li Q.-F.,Nanjing University of Aeronautics and Astronautics | Huang G.-P.,Nanjing University of Aeronautics and Astronautics | Li C.-P.,Nanjing University of Aeronautics and Astronautics | And 2 more authors.
Kung Cheng Je Wu Li Hsueh Pao/Journal of Engineering Thermophysics | Year: 2016

Data of flow field affected by unsteady jet of different frequencies in diffuser, are analyzed by the POD method, and the modal coefficients spectrum and the energy spectrum are then analyzed in order to explaining the control mechanism of flow field with unsteady excitation. The results show that: 1) The flow field tends to resonate with the unsteady excitation, and the low order modal resonates strongly while higher modal weakly; 2) 'Natural frequency' of flow field will not be changed by excitement,whereas its strength tends to be stronger or weaker, and so as the field 'protection' mechanism; 3) Energy spectrum demonstrates that the energy percents representing the second and third modal kinetic energy become bigger by unsteady excitement, and so as those representing the first modal quasi vortex energy, indicating that the decrease of small-scale fluctuations energy and the parallel flow energy. © 2016, Science Press. All right reserved.


Liang Z.-Y.,North University of China | Gao W.,China South Industries Group Corporation | Chen Z.-G.,North University of China
Binggong Xuebao/Acta Armamentarii | Year: 2013

A metal foam/metal tube plastic deformation energy absorber is designed to reduce the high overload of projectile-borne equipment when a projectile penetrates into a target at high velocity. And the efficiency of the energy absorber to reduce the overload is studied by using finite element software LS-DYNA. The overload-time curves of projectile-borne equipment are obtained during penetrating process, and compared with the curves obtained without any measures and with metal tube plastic deformation energy absorber. The results show that the metal foam/metal tube energy absorber can drastically reduce the overload of projectile-borne equipment at high velocity, especially, the efficiency of overload reduction and the working time is better than simple metal tube energy absorber.


Wu S.-S.,South China University of Technology | Hu A.-T.,South China University of Technology | Du J.,China South Industries Group Corporation
Huanan Ligong Daxue Xuebao/Journal of South China University of Technology (Natural Science) | Year: 2015

In this paper, first, novel mechanical principle-based extrusion equipment with axial screw vibration is designed, and the principle of the axial screw vibration is analyzed. Then, according to the theory of envelopes, the mathematical equations of the undulant vibration surface are established, and a 3D model of the extrusion equipment is constructed. Moreover, by the force analysis of the vibration parts, a physical model describing the screw vibration is established, and the key parameters are theoretically inferred out. Finally, in ADMAS environment, a dynamic simulation of vibration characteristics of the extrusion equipment is carried out. The results show that the designed extrusion equipment exhibits a simple harmonic vibration waveform with small distortion and high stability, which means that the equipment is feasible and effective. ©, 2015, South China University of Technology. All right reserved.

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