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Geometric Error Identification of Gantry-Type CNC Machine Tool Based on Multi-Station Synchronization Laser Tracers

Chinese Journal of Mechanical Engineering 2024年第2期37卷 150-162页

作者： jun zha Huijie zhang School of Mechanical Engineering Xi’an Jiaotong UniversityXi’an 710049China Xi’an Jiaotong University Suzhou Academy Suzhou 215123China

Laser tracers are a three-dimensional coordinate measurement system that are widely used in industrial *** propose a geometric error identification method based on multi-station synchronization laser tracers to enable the rapid and high-precision measurement of geometric errors for gantry-type computer numerical control(CNC)machine *** method also improves on the existing measurement efficiency issues in the single-base station measurement method and multi-base station time-sharing measurement *** consider a three-axis gantry-type CNC machine tool,and the geometric error mathematical model is derived and established based on the combination of screw theory and a topological analysis of the machine kinematic *** four-station laser tracers position and measurement points are realized based on the multi-point positioning principle.A self-calibration algorithm is proposed for the coordinate calibration process of a laser tracer using the Levenberg-Marquardt nonlinear least squares method,and the geometric error is solved using Taylor’s first-order linearization *** experimental results show that the geometric error calculated based on this modeling method is comparable to the results from the Etalon laser *** a volume of 800 mm×1000 mm×350 mm,the maximum differences of the linear,angular,and spatial position errors were 2.0μm,2.7μrad,and 12.0μm,respectively,which verifies the accuracy of the proposed *** research proposes a modeling method for the precise measurement of errors in machine tools,and the applied nature of this study also makes it relevant both to researchers and those in the industrial sector.

关键词： Multi-point positioning Multi-station synchronization CNC machine tool Geometric error Error separation

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Modular Verification of SPARCv8 Code

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Journal of Computer Science & Technology 2020年第6期35卷 1382-1405页

作者： jun-Peng zha Xin-Yu Feng Lei Qiao Department of Computer Science and Technology Nanjing UniversityNanjing 210023China State Key Laboratory for Novel Software Technology Nanjing UniversityNanjing 210023China Beijing Institute of Control Engineering Beijing 100080China

Inline assembly code is common in system software to interact with the underlying hardware platforms. The safety and correctness of the assembly code is crucial to guarantee the safety of the whole system. In this paper, we propose a practical Hoare-style program logic for verifying SPARC (Scalable Processor Architecture) assembly code. The logic supports modular reasoning about the main features of SPARCv8 ISA (instruction set architecture), including delayed control transfers, delayed writes to special registers, and register windows. It also supports relational reasoning for refinement verification. We have applied it to verify that there is a contextual refinement between a context switch routine in SPARCv8 and a switch primitive. The program logic and its soundness proof have been mechanized in Coq.

关键词： Scalable Processor Architecture Version 8(SPARCv8) assembly code verification context switch Coq refinement verification

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Effect of Working Position on Vertical Motion Straightness of Open Hydrostatic Guideways in Grinding Machine

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Chinese Journal of Mechanical Engineering 2017年第1期30卷 46-52页

作者： zha jun WANG Zhiwei XUE Fei CHEN Yaolong State Key Laboratory for Manufacturing Systems Engineering Xi 'an Jiaotong University Xi 'an 710049 China College of Mechanical and Electronic Engineering Shandong University of Science and Technology Qingdao 266590 China

Hydrostatic guideways have various applications in precision machine tools due to their high motion accuracy. The analysis of motion straightness in hydrostatic guideways is generally ignoring the external load on the slider. A variation force also exists, caused by the different working positions, together with the dead load of the slider and that of other auxiliary devices. The effect of working position on vertical motion straightness is investigated based on the equivalent static model, considering the error averaging effort of pressured oil film in open hydrostatic guideways. Open hydrostatic guideways in LGF1000 are analyzed with this approach. The theoretical results show that the slider has maximum vertical motion straightness when the working position is closer the guiderail of Y axis. The vertical motion straightness reaches a minimum value as the working position is located at the center of the two guiderails on the Y axis. The difference between the maximum and minimum vertical motion straightness is 34.7%. The smaller vertical motion straightness is attributed to the smaller spacing of the two pads centers, along the Y direction. The experimental results show that the vertical motion straightness is 4.15 μm/1200 mm, when the working position is located in the middle of the Xbeam, and 5.08 pro/1200 mm, when the working position is approaching the Y guiderails, denoting an increase of 18.3%. The changing trends of the measured results validate the correctness of the theoretical model. The research work can be used to reveal the variation law of accuracy of the open hydrostatic guideways, under different working positions, to predict the machining precision, and provides the basis for an error compensation strategy for gantry type grinding machines.

关键词： open hydrostatic guideways error averaging vertical motion straightness working position

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Multi-dimensional controllability analysis of precision ball bearing integrity

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Advances in Manufacturing 2023年第4期11卷 682-693页

作者： Lai Hu jun zha Wei-Hua zhao Xiao-Fei Peng Yao-Long Chen School of Mechanical Engineering Xi’an Jiaotong UniversityXi’an710049People’s Republic of China State Key Laboratory for Manufacturing Systems Engineering Xi’an Jiaotong UniversityXi’an710054People’s Republic of China Luoyang Bearing Science and Technology Co. Ltd.Luoyang471039HenanPeople’s Republic of China

Many factors affect the integrity of precision ball *** this study,the multi-dimensional controllability of precision ball bearings produced in different company brands(bearing A and bearing B)were studied and *** geometric errors(flatness,parallelism,roundness and cylindricity of inner and outer rings,roundness,groove and roughness of inner and outer rings)and vibration errors of bearings were ***,the residual stress,residual austenite content,element content ratio,metamorphic layer and temperature-vibration displacement coupling test were also *** on the above analysis conclusion,the bearing fatigue life test was carried out for 2150 *** reliability of the conclusion is proved again as *** the residual austenite content in the raceway of precision ball bearing is 10%,the axial residual stress is 877.4 MPa;the tangential residual stress is 488.1 MPa;the carbon content is 6%;the test temperature of bearing is the lowest;and the service life is prolonged.

关键词： Precision ball bearing Controllability Geometric errors Carbon content Residual austenite Residual stress

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Theoretical analysis and application of polymer-matrix field grading materials in HVDC cable terminals

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High Voltage 2017年第1期2卷 39-46页

作者： Peng Han jun-Wei zha Si-Jiao Wang Zhi-Min Dang Department of Polymer Science and Engineering University of Science and Technology BeijingBeijing 100083People’s Republic of China State Key Laboratory of Power System and Department of Electrical Engineering Tsinghua UniversityBeijing 100084People’s Republic of China

The distortion and uneven distribution of electric field in high-voltage direct current(HVDC)terminal insulator is the key problem for stable running of the power transmission *** flexible materials filled polymer-matrix composites with non-linear conductivity have also been considered to modify the distribution of electric field in cable *** factors having influence on the non-linear conductivity will be analysed in this review.

关键词： field conductivity matrix

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Recent Progress on Aeroelasticity of High-Performance Morphing UAVs

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Computer Modeling in Engineering & Sciences 2022年第10期133卷 1-29页

作者： Binbin Lv jun zha Kaichun Zeng Hongtao Guo Li Yu Peng zhang Institute of High Speed Aerodynamics China Aerodynamics Research and Development CenterMianyang621000China

The high-performance morphing aircraft has become a research focus all over the *** morphing aircraft,unlike regular unmanned aerial vehicles(UAVs),has more complicated aerodynamic characteristics,making itmore difficultto conduct its design,model analysis,and *** paper reviews the recent process and the current status of aeroelastic issues,numerical simulations,and wind tunnel test of morphing *** evaluation of aerodynamic characteristics,mechanism,and relevant unsteady dynamic aerodynamicmodeling throughout the morphing process are the primary technological bottlenecks formorphing *** unstable aerodynamic forces have a significant impact on the aircraft handling characteristics,control law design,and flight *** the past,the structural analysis of morphing aircrafts,flight dynamics modeling,computational mesh morphing technology,and aerodynamic calculation were performed in promoting the development of next generation UAVs,with nonlinear dynamic challenges includingtransonic aeroelastic problems and high angle of attack aeroelastic *** present,many facets of these difficulties,together with the accompanying numerical simulation studies,remain *** addition,wind tunnel experiments face significant challenges in the dynamic morphing ***,dynamic unsteady aerodynamic characteristics in the continuous morphing process still need to be verified by more related experiments.

关键词： Morphing aircraft aeroelasticity numerical simulation wind tunnel test

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Risk factors for postpartum posttraumatic stress disorder after emergency admission

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World Journal of Emergency Medicine 2024年第2期15卷 121-125页

作者： Fengxia Du jun zha Yan Li Lichao Fang Shuyu Xia Youjia Yu Department of Obstetrics Suzhou Xiangcheng People’s HospitalSuzhou 215131China Department of Anesthesiology the Second Affiliated Hospital of Wannan Medical CollegeWuhu 241000China Department of Anesthesiology Suzhou Xiangcheng People’s HospitalSuzhou 215131China Department of Emergency and Intensive Care Unit Suzhou Xiangcheng People’s HospitalSuzhou 215131China

BACKGROUND:Postpartum posttraumatic stress disorder(PTSD)can occur in women who give birth after emergency *** identification of risk factors for this condition is crucial for developing effective preventive *** retrospective study aimed to explore the incidence and risk factors for postpartum PTSD in women who give birth after emergency ***:Medical records of women who gave birth after emergency admission were collected between March 2021 and April *** patients’general conditions and perinatal clinical indicators were *** puerperae were divided into PTSD group and control group based on symptom occurrence at six weeks *** logistic regression analysis was performed to identify risk ***:A total of 276 puerperae were included,with a PTSD incidence of 20.3% at six weeks *** logistic regression analysis identified emergency cesarean section(odds ratio[OR]=2.102;95%confidence interval[CI]:1.114-3.966,P=0.022),admission to the emergency department after midnight(12:00 AM)(OR=2.245;95%CI:1.170-4.305,P<0.001),and cervical dilation(OR=3.203;95%CI:1.670–6.141,P=0.039)as independent risk factors for postpartum *** pump use(OR=0.500;95%CI:0.259–0.966,P=0.015)was found to be a protective factor against postpartum ***:Emergency cesarean section,admission to the emergency department after midnight,and cervical dilation were identified as independent risk factors for postpartum PTSD,while analgesic pump use was a protective *** findings provide insights for developing more effective preventive measures for women who give birth after emergency admission.

关键词： Risk factors Posttraumatic stress disorder Emergency Delivery

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Residual field suppression for magnetocardiography measurement inside a thin magnetically shielded room using bi-planar coil

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Chinese Physics B 2022年第7期31卷 229-234页

作者： Kang Yang Hong-Wei zhang Qian-Nian zhang jun-jun zha Deng-Chao Huang College of Electrical Engineering Anhui Polytechnic UniversityWuhu 241000China Key Laboratory of Advanced Perception and Intelligent Control of High-end Equipment Ministry of EducationAnhui Polytechnic UniversityWuhu 241000China

For a magnetocardiography(MCG)system inside a magnetically shielded room(MSR),the residual field should be further suppressed to obtain high-quality MCG *** this paper,a compensation system has been developed based on the bi-planar coil and the proportional-integral-derivative(PID)*** bi-planar coil,derived from the target-field theory and the Tikhonov regularization method,is utilized to generate magnetic field with high uniformity in the predefined target *** the PID controller is introduced to provide dynamic compensation current for the coil,according to the residual field change monitored by a reference SQUID *** measurement results show that the noise suppression ratio(NSR)can reach above 20 dB in the low-frequency range from 0.1 Hz to 50 *** DC component and the fluctuation of the residual field in time-domain can be respectively suppressed to 0 p T and 4 p T,indicating that this proposed compensation method is useful for the MCG measurement.

关键词： SQUID magnetocardiography bi-planar coil active compensation

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Self-assembled core-shell polydopamine@MXene with synergistic solar absorption capability for highly efficient solar-to-vapor generation

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Nano Research 2020年第1期13卷 255-264页

作者： Xing zhao Xiang-jun zha Li-Sheng Tang jun-Hong Pu Kai Ke Rui-Ying Bao Zheng-ying Liu Ming-Bo Yang Wei Yang College of Polymer Science and Engineering Sichuan UniversityState Key Laboratory of Polymer Materials EngineeringChengdu610065China

As a renewable and environment-friendly technology for seawater desalination and wastewater purification,solar energy triggered steam generation is attractive to address the long-standing global water scarcity ***,practical utilization of solar energy for steam generation is severely restricted by the complex synthesis,low energy conversion efficiency,insufficient solar spectrum absorption and water extraction capability of state-of-the-art ***,for the first time,we report a facile strategy to realize hydrogen bond induced self-assembly of a polydopamine(PDA)@MXene microsphere photothermal layer for synergistically achieving wide-spectrum and highly efficient solar absorption capability(≈96%in a wide solar spectrum range of 250–1,500 nm wavelength).Moreover,such a system renders fast water transport and vapor escaping due to the intrinsically hydrophilic nature of both MXene and PDA,as well as the interspacing between core-shell *** solar-to-vapor conversion efficiencies under the solar illumination of 1 sun and 4 sun are as high as 85.2%and 93.6%,***,the PDA@MXene photothermal layer renders the system durable mechanical properties,allowing producing clean water from seawater with the salt rejection rate beyond 99%.Furthermore,stable light absorption performance can be achieved and well maintained due to the formation of ternary TiO2/C/MXene complex caused by oxidative degradation of ***,this work proposes an attractive MXene-assisted strategy for fabricating high performance photothermal composites for advanced solar-driven seawater desalination applications.

关键词： self-assembly polydopamine(PDA)@MXene microsphere synergistic light absorption solar-to-vapor generation light absorption stability

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Improvements of dielectric properties and energy storage performances in BaTiO_(3)/PVDF nanocomposites by employing a thermal treatment process

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Journal of Advanced Dielectrics 2018年第6期8卷 108-117页

作者： Yue-Mao Dang Ming-Sheng Zheng jun-Wei zha Tsinghua University High School Beijing 100084 P.R.China School of Biological and Chemical Engineering University of Science and Technology Beijing Beijing 100083 P.R.China

The influence of thermal treatment on the dielectric properties and energy storage performances of a classical dielectric nanocomposite system(barium titanate/polyvinylidene fluoride PVDF)was discussed *** results demonstrated that the permittivity of thermal treated nanocomposites increased and dielectric loss decreased compared with the untreated *** addition,the energy density was also greatly improved due to the inclined residual *** example,the energy density of the treated nanocomposite with 50 vol.%nanofillers was 3.14 times higher than the untreated nanocomposite at 50 MV/***,the charge–discharge efficiency was also promoted from 6.36%to 56.89%.According to the viewpoint of microstructure,the improvement of the dielectric and energy storage properties would be ascribed to the suppression on void defects in the interphase of dielectric nanocomposite by employing the thermal treatment ***,thermal treatment turns out to be a simple and an effective method to improve the dielectric performances and energy storage properties in the dielectric nanocomposites.

关键词： Thermal treatment BaTiO_(3)/PVDF nanocomposites dielectric properties energy storage

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