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Investigations of high-frequency induction hardening process for piston rod of shock absorber

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Journal of University of Science and Technology Beijing 2005年第1期12卷 85-89页

作者： XianhuaCheng QianqianShangguan schoolofmechanical＆PowerEngineering ShanghaiJiaotongUniversityShanghai200030China

The microhardness of piston rods treated with different induction hardening processes was tested. The experimental results reveal that the depth of the hardened zone is proportional to the ratio of the moving speed of the piston rod to the output power of the induction generator. This result is proved correct through the Finite Element Method (FEM) simulation of the thermal field of induction heating. From tensile and impact tests, an optimized high frequency induction hardening process for piston rods has been obtained, where the output power was 82%×80 kW and the moving speed of workpiece was 5364 mm/min. The piston rods, treated by the optimized high frequency induction hardening process, show the best comprehensive mechanical performance.

关键词： high-frequency induction hardening piston rod mechanical properties finite element method numerical simulation

Study on Contact Fatigue Life and Failure Mechanism of Subquenched 42CrMo Steel

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材料热处理学报 2004年第5期25卷 260-262页

作者： HEBo-lin YUYing-xia SHAOEr-yu schoolofmechanical＆ElectricalEngineering EastChinaJiaotongUniversityNanchangChina MaterialInstitute HenanUniversityofScienceandTechnologyLuoyangChina

The effect of undissolved ferrite amount in subcritically quenched 42CrMo steel on contact fatigue properties and failure mechanism were studied. The amount of undissolved ferrite in the steel were 0%,3%,10%,15% and 20% in volume fraction, respectively. The experimental results show that the existence of undissolved ferrite can increase the contact fatigue life The contact fatigue life can be prolonged with increasing the amounts of undissolved ferrite The grain size can be fined by using subcritical quenching process and the area of phase boundaries can also be greatly increased. The stress relaxation and grain refinement due to occurring of plastic deformation are main reasons for improving the fatigue life. The existence of undissolved ferrite can increase the crack initiation period. Under the experiment conditions, when the amount of undissolved ferrite is 10%, the longest contact fatigue life can be the obtained.

关键词：亚临界灭弧接触疲劳失效机理铁素体 42CrMo钢

Glass-Forming Ability of an Iron-Based Alloy Enhanced by Co Addition and Evaluated by a New Criterion

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Chinese Physics Letters 2005年第7期22卷 1736-1738页

作者：陈庆军沈军范洪波孙剑飞黄永江 MCCARTNEYD.G. SchoolofMaterialsScienceandEngineering HarbinInstituteofTechnologyHarbin150001 SchoolofMaterialsScienceandEngineering HarbinInstituteofTechnologyHarbin150001//SchoolofMechanicalMaterialsandManufacturingEngineeringUniversityofNottinghamUniversityParkNottinghamNG72RDUK schoolofmechanical MaterialsandManufacturingEngineeringUniversityofNottinghamUniversityParkNottinghamNG72RDUK

A new Fe-based alloy that can be cast into a fully amorphous rod with a diameter of at least 16mm by the conventional copper-mould casting technique is obtained by partially replacing Fe with Co in a previously reported Fe-based bulk metallic glass. The preliminary thermodynamic analysis indicates that the Co-containing alloy has a significantly lower Gibbs free energy difference between the undercooled melt and the corresponding crystalline solid, compared to the Co-free alloy, reflecting the dramatic role of the Co addition in stabilizing the supercooled melt and facilitating glass formation in iron-based alloys. Here, a new criterion, derived from the classical nucleation and growth theory, is introduced to evaluate the glass-forming ability of Fe-based bulk metallic glasses.

关键词： GFA DTA XRD

A Feasibility Study on ECT Monitoring of Froth Molding of Polyurethane

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Journal of Thermal Science 2005年第1期14卷 92-96页

作者： QiCHEN ShiLIU XiangyuanDONG schoolofmechanical ElectronicandControlEngineeringBeijingJiaotongUniversityBeijing100044China InstituteofEngineeringThermophysics ChineseAcademyofSciencesBeijing100080China

This paper presents our recent experimental investigation on the feasibility of monitoring the froth molding, a special case of solidification process, of polyurethane by using electrical capacitance tomography. The major challenge is the extremely low solid density of the solidified material during the process due to the very large expansion ratio. Suitable calibration method is sought and adequate image reconstruction algorithm is applied for such a task. Different expansion modes have been observed during experiment and corresponding images reconstructed. This visualization technique clearly revealed the expansion process by a time series of images of the solid density. The test results proved the capability of electrical capacitance tomography in monitoring the expansion of polyurethane. Future ways for improvement are also suggested.

关键词： electrical capacitance tomography froth molding.

Nano-Crystalline Diamond Films with Pineapple-Like Morphology Grown by the DC Arcjet vapor Deposition Method

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Chinese Physics Letters 2014年第8期31卷 167-169页

作者：李彬张勤俭石彦超李佳君李宏吕反修陈广超 SchoolofMetallurgicalandEcologicalEbgineering UniversityofScienceandTechnologyBeijingBeijing100083 schoolofmechanical ElectronicandControlEngineeringBeijingJiaotongUniversityBeijing100044 CollegeofMaterialsScienceandOpto-electronicTechnology UniversityofChineseAcademyoiSciencesBeijing100049

A nano-crystlline diamond film is grown by the dc arcjet chemical vapor deposition method. The film is characterized by scanning electron microscopy, high-resolution transmission electron microscopy （HRTEM）, x-ray diffraction （XRD） and Ftaman spectra, respectively. The nanocrystalline grains are averagely with 80hm in the size measured by XRD, and further proven by Raman and HRTEM. The observed novel morphology of the growth surface, pineapple-like morphology, is constructed by cubo-octahedral growth zones with a smooth faceted top surface and coarse side surfaces. The as-grown film possesses （100） dominant surface containing a little amorphous sp2 component, which is far different from the nano-crystalline film with the usual cauliflower-like morphology.

关键词： Diamond films

DYNAMIC MATHEMATICAL MODELING AND APPLICATION FOR PUMPING SYSTEM PERFORMANCE INTEGRATED EVALUATION

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Chinese Journal of Mechanical Engineering 2003年第3期16卷 285-288页

作者： ChenHongxun WangJian WuYuejun ShanghaiInstituteofAppliedMathematics&Mechanics ShanghaiUniversityShanghai200072China schoolofmechanical&EleclronicEngineeringandAutomation ShanghaiUniversityShanghai200072China

A mathematical model is set to evaluate the overall centrifugal pumpingsystem using asynchronous motor as power. This method can be used to affirm system performanceaccording the transform and the aberrance of interior parameters and exterior performance curves soas to give a reference to the equipment amelioration. The analysis of emulation experiment datasuggests the model is effectively used.

关键词： Pumping system Mathematical model Performance evaluation

STOCHASTIC OBJECT-ORIENTED PETRI NETS (SOPNS) AND ITS APPLICATION IN MODELING OF MANUFACTURING SYSTEM RELIABILITY

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Chinese Journal of Mechanical Engineering 2003年第3期16卷 272-276,284页

作者： JiangZhibin HeJunming DepartmentofIndustrialEngineering&Management ShanghaiJiaotongUniversityShanghai200030China schoolofmechanical&AutomotiveEngineering HefeiUniversityofTechnologyHefei230009China

Object-oriented Petri nets (OPNs) is extended into stochastic object-oriented Petri nets (SOPNs) by associating the OPN of an object with stochastic transitions and introducing stochastic places. The stochastic transition of the SOPNs of a production resources can be used to model its reliability, while the SOPN of a production resource can describe its performance with reliability considered. The SOPN model of a case production system is built to illustrate the relationship between the system's performances and the failures of individual production resources.

关键词： Stochastic object-oriented Petri nets Modeling Reliability Manufacturing system

Hardness variations during aging process of deformed W-Ni-Fe ternary alloys with high nickel-to-iron ratios

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Journal of University of Science and Technology Beijing 2003年第4期10卷 78-80页

作者： RonghuaLi JihuaHuang ShengYin JunZhao schoolofmechanical EleOronicandControlEngineeringNorthernJiaotongUniversityBeijing100044China MaterialsScienceandEngineeringSchool UniversityofScienceandTechnologyBeijingBeijing100083China

The aging precipitation behavior of beta phase in two kinds of alloys with7/3 and 9/1 ssickel4o-iron ratios during aging at 800 deg C after deformation was studied. Theresults show that there are two different kinds of aging hardness variation mechanisms (thesoftening mechanism and the hardening mechanism) deciding the hardness variations of the *** Ni/Fe is smaller than8/2, there is only the softening mechanism which results from the decreasing of dislocation densityand recovery or re-crystallization. And when NI/Fe is greater than 8/2 besides the softeningmechanism there is still the hardening mechanism that is induced by the precipitation of beta phase.

关键词： W-Ni-Fe ternary system aging precipitationss

Improving Reliability of Communication in RS-485 Design

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Journal of China University of Mining and Technology 2002年第2期12卷 219-221页

作者：蒋小平刘晓辉 schoolofmechanical

Three aspects of RS 485 application, which affect the reliability of communication of data system are analyzed and discussed. In network configuration, it presents the optimal configuration for the bus of RS 485, the better rule for derivative line and the choice for termination. In hardware design, it presents three parts of driver’s peripheral circuit. In control software design, it presents a method of using 75176’s DE line to control the driver.

关键词： communication RS 485 reliability data trasmission