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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 zha.g 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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Photothermal-photocatalytic thin-layer flow system for synergistic treatment of wastewater

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Chinese Journal of Chemical Engineering 2023年第11期63卷 120-129页

作者： Zhongjiao zha jun Wu Shaoping Tong Xuebo Cao College of Chemical Engineering State Key Laboratory Breeding Base of Green Chemistry-Synthesis TechnologyZhejiang University of TechnologyHangzhou 310014China College of Biological Chemical Sciences and EngineeringJiaxing UniversityJiaxing 314001China College of Advanced Materials Engineering Jiaxing Nanhu UniversityJiaxing 314001China

The integration of the photocatalytic effect into solar steam is highly desirable for addressing freshwater shortages and water ***,a ternary film structure for the adsorption and photothermal and photocatalytic treatment of wastewater was designed by combining the technique of self-assembled carbon nano paper with a nitrogen composite titanium dioxide(N-TiO_(2))deposited on the surface of carbon nanotubes(CNT)using polyvinylidene fluoride(PVDF)as a *** photogeneration of reactive oxygen species can be promoted by rapid oxygen diffusion at the three-phase interface,whereas the interfacial photothermal effect promotes subsequent free radical reactions for the degradation of rhodamine B(93%).The freshwater evaporation rate is 1.35 kg·m^(-2)·h^(-1)and the solar-to-water evaporation efficiency is 94%.Importantly,the N-TiO_(2)/CNT/PVDF(N-TCP)film not only effectively resists mechanical damage from the environment and maintains structural integrity,but can also be made into a large film for outdoor experiments in a large solar energy conversion device to collect fresh water from polluted water and degrade organic dyes in source water simultaneously,opening the way for applications in energy conversion and storage.

关键词： Wastewater disposal Solar-driven distill Thin-layer flow Clean water production Ternary film

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COMPARISON OF gRANULAR MATERIAL BEHAVIOUR UNDER DRAINED TRIAXIAL AND PLANE STRAIN CONDITIONS USINg 3D DEM SIMULATIONS

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Acta Mechanica Solida Sinica 2012年第2期25卷 186-196页

作者： guobin gong Xiaoxiong zha jun Wei Civil and Environmental Engineering Graduate School in ShenzhenHarbin Institute of TechnologyHIT campusUniversity TownXiliNanshan DistrictShenzhen 518055China (2 School of Civil Engineering Central Sourh UniversityChangsha 410004China

Three dimensional （3D） DEM （discrete element method） simulations of drained triaxial compression and plane strain tests are presented for both dense and loose assemblies of polydisperse spheres using a periodic cell. In the work reported, drained tests were modelled by deforming the samples under constant mean stress conditions. The drained behaviour is shown to be qualitatively similar to published physical experimental results. The Bishop＇s formula for the estimation of the intermediate principal stress is evaluated. The existence of critical density is shown to be independent of initial packing densities and strain conditions. Different failure criteria have been compared based on the DEM simulation results, and the Lade criterion is found to be the most appropriate one. A new microscopic fabric parameter is introduced to give insight to structural anisotropy under general 3D fabric conditions. It is found that two parameters characterize the evolution of the stress and fabric respectively independent of strain conditions.

关键词： DEM simulations drained constant mean stress failure criteria fabric

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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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Simulation of dual transponder carrier ranging measurements

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第10期10卷 1395-1403页

作者： Xiang-yu zha Xiao-jun JIN Zhong-he JIN Department of lnformation Science and Electronic Engineering Zhejiang University Hangzhou 310027 China

The most dominant error source for microwave ranging is the frequency instability of the oscillator that generates the carrier phase signal. The oscillator noise is very difficult to filter due to its extremely low frequency. A dual transponder carrier ranging method can effectively minimize the oscillator noise by combing the reference phase and the to-and-fro measurement phase from the same single oscillator. This method does not require an accurate time tagging system, since it extracts phases on the same satellite. This paper analyzes the dual transponder carrier ranging system by simulation of the phase measurements with comprehensive error models. Both frequency domain and time domain noise transfer characteristics were simulated to compare them with dual one-way ranging. The simulation results in the two domains conformed to each other and demonstrated that a high level of accuracy can also be achieved by use of the dual transponder carder ranging system, with relatively simple instruments.

关键词： Dual transponder carrier ranging Dual one-way ranging Oscillator noise Transfer characteristic

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Substrate Effect on Microstructure and Performance of LTHVOF Sprayed Copper Coatings

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稀有金属材料与工程 2012年第S1期41卷 380-383页

作者： zha Bailin Yuan Xiaojing zhan jun Jiang Peng Xian Res Inst Hitech Xian 710025 Peoples R China

The performance of copper coatings fabricated on three substrates by LTHVOF spraying process was *** shows that substrate material has little effect on phase composition of coatings,and there is no oxide in the three coatings *** coatings are dense,and demonstrate little difference on the microstructure of the inner part of the ***,microstructure of bonding area between coating and substrate shows big difference,copper coatings bonds compacter on soft substrate aluminum than hard substrate *** strength of coatings sprayed on the soft substrate is higher than that on the hard *** analysis of fracture surface shows that strong mechanical alloying phenomena when copper particles deposited on aluminum *** average bonding strength of copper coatings on 1Cr18Ni9Ti,45#steel and LY12 is relatively 18.83,17.49 and 32.14 *** have strong effect on microstructure and bonding strength,but little on phase composition...

关键词： bonding strength coating microstructure

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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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Synthesis of a kind of geminal imidazolium ionic liquid with long aliphatic chains

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Chinese Chemical Letters 2007年第1期18卷 48-50页

作者： Yun Sheng Ding Min zha jun zha.g Seng Shan Wang Department of Polymer Materials and Engineering School of Chemical Engineering Hefei University of Technology Hefei 230009 China CAS Key Laboratory of Engineering Plastics Joint Laboratory of Polymer Science and Materials Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China

A novel geminal imidazolium ionic liquid with long hydrocarbon group, 1,4-bis （3-tetradecylimidazolium- 1-yl） butane bromide was synthesized and an efficient synthesized method was introduced detailedly. Its structu... 详细信息

关键词： geminai imidazolium ionic liquid Long aliphatic chain Physicochemicai properties

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Rangeland grasshoppers in Relation to Soils in the Qinghai Lake Region, China

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Pedosphere 2007年第1期17卷 84-89页

作者： NI Shao-Xiang WANg Jie-Chen JIANg Jian-jun zha Yong College of geographical Science Nanjing Normal University Nanjing 210097 （China） Department of Urban and Resources Science Nanjing UniversityNanjing 910093 （China）

The relationship between rangeland grasshopper density and soil type as well as topsoil moisture content was analyzed with in situ soil data collected in the Qinghai Lake region of China. grasshoppers were confined mainly to the areas with light chestnut soil or chestnut soil, and very few were found in areas with subalpine meadow soil. grasshoppers were almost absent from other types of soil, such as aeolian soil. In addition, analysis of 14 soil samples collected in the study area revealed that a soil moisture content between 18 and 32 g kg-1 coincided spatially with a higher density of grasshoppers, with the grasshopper density averaging 15 head m-2. In areas with a soil moisture content above 42 g kg-1 or below 10 g kg-1, grasshopper density dropped to less than 5 head m-2. These indicated that for the study area, soils with very high or very low moisture contents were not conducive to the survival of grasshoppers.

关键词： Qinghai Lake rangeland grasshopper soil type soil moisture

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