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Sub-nanometer finishing of polycrystalline tin by inductively coupled plasma-assisted cutting

《机械工程前沿（英文）》 2023年第18卷第3期 doi: 10.1007/s11465-023-0751-5

摘要： Polycrystalline tin is an ideal excitation material for extreme ultraviolet light sources. However, the existence of grain boundary (GB) limits the surface roughness of polycrystalline tin after single-point diamond turning (SPDT). In this work, a novel method termed inductively coupled plasma (ICP)-assisted cutting was developed for the sub-nanometer finishing of polycrystalline tin. The relationship between ICP power, processing time, and modification depth was established by thermodynamic simulation, and the fitted heat transfer coefficient of polycrystalline tin was 540 W/(m²·K). The effects of large-thermal-gradient ICP treatment on the microstructure of polycrystalline tin were studied. After 0.9 kW ICP processing for 3.0 s, corresponding to the temperature gradient of 0.30 K/µm, the grain size of polycrystalline tin was expanded from a size of approximately 20–80 μm to a millimeter scale. The Taguchi method was used to investigate the effects of rotational speed, depth of cut, and feed rate on SPDT. Experiments conducted based on the ICP system indicated that the plasma-assisted cutting method promoted the reduction of the influence of GB steps on the finishing of polycrystalline tin, thereby achieving a surface finish from 8.53 to 0.80 nm in Sa. The results of residual stress release demonstrated that the residual stress of plasma-assisted turning processing after 504 h stress release was 10.7 MPa, while that of the turning process without the ICP treatment was 41.6 MPa.

关键词： plasma-assisted cutting polycrystalline tin single-point diamond turning surface roughness

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Recent advancements in optical microstructure fabrication through glass molding process

Tianfeng ZHOU,Xiaohua LIU,Zhiqiang LIANG,Yang LIU,Jiaqing XIE,Xibin WANG

《机械工程前沿（英文）》 2017年第12卷第1期页码 46-65 doi: 10.1007/s11465-017-0425-2

摘要：

Optical microstructures are increasingly applied in several fields, such as optical systems, precision measurement, and microfluid chips. Microstructures include microgrooves, microprisms, and microlenses. This paper presents an overview of optical microstructure fabrication through glass molding and highlights the applications of optical microstructures in mold fabrication and glass molding. The glass-mold interface friction and adhesion are also discussed. Moreover, the latest advancements in glass molding technologies are detailed, including new mold materials and their fabrication methods, viscoelastic constitutive modeling of glass, and microstructure molding process, as well as ultrasonic vibration-assisted molding technology.

关键词： optical microstructure microgroove microlens glass molding process single-point diamond cutting

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Fundamental frequency and testing mode of complicated elastic clamped-plate vibration

QI Hongyuan, GUAN Yiduo

《机械工程前沿（英文）》 2008年第3卷第4期页码 360-364 doi: 10.1007/s11465-008-0084-4

摘要： Aimed at the modal analysis of complicated elastic clamped-plates, a trigonometric interpolation method of conformal mapping is applied to set up the mapping function between a complicated region and a unit dish region, and the fundamental frequency of the complicated vibrating region is analyzed with the help of the Galerkin method. Taking an elastic rectangle-plate with arc radius as an example, the testing mode frequency band of plates is determined by analyzing the fundamental frequency; meanwhile, according to hamming testing method of multi-point excitation to the single-point response, and by signal processing technology and its software programming, modal parameter recognition of the elastic clamped-plate is completed. Comparing the first order modal frequency with the theoretical fundament frequency, the validity of the testing mode method and theoretical analysis are verified.

关键词： multi-point excitation rectangle-plate single-point processing technology trigonometric interpolation

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Molecular dynamics modeling of a single diamond abrasive grain in grinding

Angelos P. MARKOPOULOS,Ioannis K. SAVVOPOULOS,Nikolaos E. KARKALOS,Dimitrios E. MANOLAKOS

《机械工程前沿（英文）》 2015年第10卷第2期页码 168-175 doi: 10.1007/s11465-015-0337-y

摘要：

In this paper the nano-metric simulation of grinding of copper with diamond abrasive grains, using the molecular dynamics (MD) method, is considered. An MD model of nano-scale grinding, where a single diamond abrasive grain performs cutting of a copper workpiece, is presented. The Morse potential function is used to simulate the interactions between the atoms involved in the procedure. In the proposed model, the abrasive grain follows a curved path with decreasing depth of cut within the workpiece to simulate the actual material removal process. Three different initial depths of cut, namely 4 ?, 8 ? and 12 ?, are tested, and the influence of the depth of cut on chip formation, cutting forces and workpiece temperatures are thoroughly investigated. The simulation results indicate that with the increase of the initial depth of cut, average cutting forces also increase and therefore the temperatures on the machined surface and within the workpiece increase as well. Furthermore, the effects of the different values of the simulation variables on the chip formation mechanism are studied and discussed. With the appropriate modifications, the proposed model can be used for the simulation of various nano-machining processes and operations, in which continuum mechanics cannot be applied or experimental techniques are subjected to limitations.

关键词： molecular dynamics abrasive process chip formation cutting force temperature

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人造金刚石工业在我国迅猛崛起

刘广志

《中国工程科学》 2000年第2卷第5期页码 31-33

摘要：

论述了人造金刚石的发展历程及其在我国的迅猛发展，目前我国的人造金刚石产量已居世界首位。进入20世纪末，人造金刚石新品种不断涌现，CVD、卡邦、世界首颗超厘米级C₆₀单晶也研制成功。

关键词：人造金刚石人造金刚石膜复合片

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Multiple damage detection in complex bridges based on strain energy extracted from single point measurement

Alireza ARABHA NAJAFABADI, Farhad DANESHJOO, Hamid Reza AHMADI

《结构与土木工程前沿（英文）》 2020年第14卷第3期页码 722-730 doi: 10.1007/s11709-020-0624-5

摘要： Strain Energy of the structure can be changed with the damage at the damage location. The accurate detection of the damage location using this index in a force system is dependent on the degree of accuracy in determining the structure deformation function before and after damage. The use of modal-based methods to identify damage in complex bridges is always associated with problems due to the need to consider the effects of higher modes and the adverse effect of operational conditions on the extraction of structural modal parameters. In this paper, the deformation of the structure was determined by the concept of influence line using the Betti-Maxwell theory. Then two damage detection indicators were developed based on strain energy variations. These indices were presented separately for bending and torsion changes. Finite element analysis of a five-span concrete curved bridge was done to validate the stated methods. Damage was simulated by decreasing stiffness at different sections of the deck. The response regarding displacement of a point on the deck was measured along each span by passing a moving load on the bridge at very low speeds. Indicators of the strain energy extracted from displacement influence line and the strain energy extracted from the rotational displacement influence line (SERIL) were calculated for the studied bridge. The results show that the proposed methods have well identified the location of the damage by significantly reducing the number of sensors required to record the response. Also, the location of symmetric damages is detected with high resolution using SERIL.

关键词： damage detection strain energy influence line complex bridges rotation displacement

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Renewable synthetic fuel: turning carbon dioxide back into fuel

《能源前沿（英文）》 2022年第16卷第2期页码 145-149 doi: 10.1007/s11708-022-0828-6

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Design and locomotion analysis of two kinds of rolling expandable mobile linkages with a single degree

Yanlin HAO, Yaobin TIAN, Jianxu WU, Yezhuo LI, Yan-An YAO

《机械工程前沿（英文）》 2020年第15卷第3期页码 365-373 doi: 10.1007/s11465-020-0585-3

摘要： This study presents two kinds of rolling robots that are able to roll by deforming their outer shapes with a single degree of freedom. Each robot is an essential multi-loop planar expandable linkage constructed by a concave outer loop and several inner parallelogram loops. In this study, the mechanical design of the robots is introduced. Dynamic rolling process is further analyzed on the basis of zero moment point method, and a morphing strategy is proposed to guarantee a stable dynamic rolling process. A novel passive rolling locomotion is also developed, which enables the robots to roll and stand on a slope. To verify the design, two prototypes are manufactured, wherein the dynamic and passive rolling locomotion are carried out.

关键词： rolling locomotion expandable mechanism mechanism design zero moment point (ZMP) analysis

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Recognition of diamond grains on surface of fine diamond grinding wheel

HUO Fengwei, JIN Zhuji, KANG Renke, GUO Dongming, YANG Chun

《机械工程前沿（英文）》 2008年第3卷第3期页码 325-331 doi: 10.1007/s11465-008-0071-9

摘要： The accurate evaluation of grinding wheel surface topography, which is necessary for the investigation of the grinding principle, optimism, modeling, and simulation of a grinding process, significantly depends on the accurate recognition of abrasive grains from the measured wheel surface. A detailed analysis of the grain size distribution characteristics and grain profile wavelength of the fine diamond grinding wheel used for ultra-precision grinding is presented. The requirements of the spatial sampling interval and sampling area for instruments to measure the surface topography of a diamond grinding wheel are discussed. To recognize diamond grains, digital filtering is used to eliminate the high frequency disturbance from the measured 3D digital surface of the grinding wheel, the geometric features of diamond grains are then extracted from the filtered 3D digital surface, and a method based on the grain profile frequency characteristics, diamond grain curvature, and distance between two adjacent diamond grains is proposed. A 3D surface profiler based on scanning white light interferometry is used to measure the 3D surface topography of a #3000 mesh resin bonded diamond grinding wheel, and the diamond grains are then recognized from the 3D digital surface. The experimental result shows that the proposed method is reasonable and effective.

关键词： topography frequency disturbance filtering analysis wavelength

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Ultra-precision ductile grinding of BK7 using super abrasive diamond wheel

ZHAO Qingliang, Brinksmeier Ekkard, Riemer Oltmann, Rickens Kai

《机械工程前沿（英文）》 2007年第2卷第3期页码 350-355 doi: 10.1007/s11465-007-0061-3

摘要： In this paper, a novel conditioning technique using copper bonded diamond grinding wheels of 91 yD grain size and electrolytic in-process dressing (ELID) is first developed to precisely and effectively condition a nickel-electroplated monolayer coarse-grained diamond grinding wheel of 151 μm grain size. Under optimised conditioning parameters, the super abrasive diamond wheel was well conditioned in terms of a minimized run-out error and flattened diamond grain surfaces of constant peripheral envelope. The conditioning force was monitored by a force transducer, while the modified wheel surface status was in-situ monitored by a coaxial optical distance measurement system. Finally, the grinding experiment on BK7 was conducted using the well-conditioned wheel with the corresponding surface morphology and subsurface damage measured by atomic force microscope (AFM) and scanning electric microscope (SEM), respectively. The experimental result shows that the newly developed conditioning technique is applicable and feasible to ductile grinding optical glass featuring nano scale surface roughness, indicating the potential of super abrasive diamond wheels in ductile machining brittle materials.

关键词： ELID peripheral electrolytic in-process nickel-electroplated monolayer measurement

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Prediction of cutting force in turning of UD-GFRP using mathematical model and simulated annealing

Meenu GUPTA, Surinder Kumar GILL

《机械工程前沿（英文）》 2012年第7卷第4期页码 417-426 doi: 10.1007/s11465-012-0343-2

摘要：

Glass fiber reinforced plastics (GFRPs) composite is considered to be an alternative to heavy exortic materials. According to the need for accurate machining of composites has increased enormously. During machining, the obtaining cutting force is an important aspect. The present investigation deals with the study and development of a cutting force prediction model for the machining of unidirectional glass fiber reinforced plastics (UD-GFRP) composite using regression modeling and optimization by simulated annealing. The process parameters considered include cutting speed, feed rate and depth of cut. The predicted values radial cutting force model is compared with the experimental values. The results of prediction are quite close with the experimental values. The influences of different parameters in machining of UD-GFRP composite have been analyzed.

关键词： UD-GFRP ANOVA radial cutting force PCD tool Taguchi method regression analysis simulated annealing multi objective techniques

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Shadow obstacle model for realistic corner-turning behavior in crowd simulation

Gao-qi HE,Yi JIN,Qi CHEN,Zhen LIU,Wen-hui YUE,Xing-jian LU

《信息与电子工程前沿（英文）》 2016年第17卷第3期页码 200-211 doi: 10.1631/FITEE.1500253

摘要： This paper describes a novel model known as the shadow obstacle model to generate a realistic corner-turning behavior in crowd simulation. The motivation for this model comes from the observation that people tend to choose a safer route rather than a shorter one when turning a corner. To calculate a safer route, an optimization method is proposed to generate the corner-turning rule that maximizes the viewing range for the agents. By combining psychological and physical forces together, a full crowd simulation framework is established to provide a more realistic crowd simulation. We demonstrate that our model produces a more realistic corner-turning behavior by comparison with real data obtained from the experiments. Finally, we perform parameter analysis to show the believability of our model through a series of experiments.

关键词： Corner-turning behavior Crowd simulation Safety awareness Rule-based model

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Application of high-turning bowed compressor stator to redesign of highly loaded fan stage

LI Shaobin, SU Jiexian, WANG Zhongqi

《能源前沿（英文）》 2008年第2卷第4期页码 534-540 doi: 10.1007/s11708-008-0066-6

摘要： A redesign of a highly loaded fan stage by using high-turning bowed compressor stator was conducted. The original tandem stator was replaced by the highly loaded bowed stator which was applicable to highly subsonic flow conditions. 3D contouring technique and local modification of blade were applied to the design of the bowed blade in order to improve the aerodynamic performance and the matching of the rotor and stator blade rows. Performance curves at different rotating speeds and performances at different operating points for both the original fan stage and redesigned fan stage were obtained by numerical simulations. The results show that the highly loaded bowed stator can be used not only to improve the structure and the aerodynamic performances at various operating points of the compressor stage but also to provide high performances at off-design conditions. It is believed that the highly loaded bowed stator can advance the design of high-performance compressor.

关键词： off-design different numerical contouring technique high-performance compressor

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蛇绿岩型金刚石——探索深部碳循环的新窗口 Review

连东洋, 杨经绥

《工程（英文）》 2019年第5卷第3期页码 406-420 doi: 10.1016/j.eng.2019.02.006

摘要：

近些年来，在全球不同地区的一些蛇绿岩地幔橄榄岩和铬铁矿中发现了微粒金刚石和其他异常矿物，包括呈斯石英假象的柯石英、碳化硅、青松矿、自然元素矿物、金属合金以及一些壳源矿物（如锆石、石英、角闪石和金红石）。西藏罗布莎铬铁矿中的柯石英和蓝晶石呈针柱状集合体交生在一起，产在钛铁合金矿物的边部，这些柯石英集合体可能代表了更高压相的斯石英发生退变后形成的假象矿物。蓝晶石、柯石英、青松矿包裹体（一种立方晶系的氮化硼）以及TiO2 II（金红石的高压相矿物）等矿物的发现指示铬铁矿形成的温压条件可能达到10~15 GPa、约1300 ℃，深度达大于380 km 的地幔转换带（mantle transition zone，MTZ）深度。碳化硅、自然元素矿物以及金属合金矿物的产出指示了一个超还原的地质环境。与金伯利岩、变质岩和陨石中的金刚石相比，蛇绿岩中的金刚石具有较轻的碳同位素组成以及不同类型的矿物包裹体，指示其碳物质可能源于地表的有机碳，经历了俯冲板片在深部的再循环作用。金刚石在蛇绿岩地幔橄榄岩和铬铁矿中的普遍存在，表明大洋地幔可能是一个重要的碳储库。蛇绿岩型金刚石的发现证明了浅部碳可以俯冲至深部地幔。蛇绿岩型金刚石为研究地球的深部碳循环提供了新窗口。

关键词：蛇绿岩型金刚石柯石英斯石英豆荚状铬铁矿地幔过渡带

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Multi-objective optimization of process parameters in Electro-Discharge Diamond Face Grinding based on

Ravindra Nath YADAV, Vinod YADAVA, G.K. SINGH

《机械工程前沿（英文）》 2013年第8卷第3期页码 319-332 doi: 10.1007/s11465-013-0269-3

摘要：

The effective study of hybrid machining processes (HMPs), in terms of modeling and optimization has always been a challenge to the researchers. The combined approach of Artificial Neural Network (ANN) and Non-Dominated Sorting Genetic Algorithm-II (NSGA-II) has attracted attention of researchers for modeling and optimization of the complex machining processes. In this paper, a hybrid machining process of Electrical Discharge Face Grinding (EDFG) and Diamond Face Grinding (DFG) named as Electrical Discharge Diamond face Grinding (EDDFG) have been studied using a hybrid methodology of ANN-NSGA-II. In this study, ANN has been used for modeling while NSGA-II is used to optimize the control parameters of the EDDFG process. For observations of input-output relations, the experiments were conducted on a self developed face grinding setup, which is attached with the ram of EDM machine. During experimentation, the wheel speed, pulse current, pulse on-time and duty factor are taken as input parameters while output parameters are material removal rate (MRR) and average surface roughness (R_a). The results have shown that the developed ANN model is capable to predict the output responses within the acceptable limit for a given set of input parameters. It has also been found that hybrid approach of ANN-NSGA-II gives a set of optimal solutions for getting appropriate value of outputs with multiple objectives.

关键词： hybrid machining processes (HMPs) electrical discharge diamond grinding (EDDG) artificial neural network (ANN) genetic algorithm modeling and optimization