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MECHANICAL-ELECTRIC COUPLING DYNAMICAL CHARACTERISTICS OF AN ULTRA-HIGH SPEED GRINDING MOTORIZED SPINDLE SYSTEM 被引量:23
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作者 LUE Lang XIONG Wanli GAO Hang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2008年第5期34-40,共7页
On the basis of the traditional mechanical model of a grinding wheel rotor and the mechanical-electric coupling model with ideal sinusoidal supply, taking high-frequency converting current of inverter power switches i... On the basis of the traditional mechanical model of a grinding wheel rotor and the mechanical-electric coupling model with ideal sinusoidal supply, taking high-frequency converting current of inverter power switches into further consideration, a modified mechanical-electric coupling model is created. The created model consists of an inverter, a motorized spindle, a grinding wheel and grinding loads. Some typical non-stationary processes of the grinding system with two different supplies, including the starting, the speed rising and the break in grinding loads, are compared by making use of the created model. One supply is an ideal sinusoidal voltage source, the other is an inverter. The theoretical analysis of the high-order harmonic is also compared with the experimental result. The material strategy of suppressing high-order harmonic mechanical-electric coupling vibration by optimizing inverter operating parameters is proposed. 展开更多
关键词 ultra-high speed grinding Motorized spindle Mechanical-electric coupling Vibration Suppression
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Controllable and high-throughput preparation of microdroplet using an ultra-high speed rotating packed bed
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作者 Jing Xie Xiangbi Jia +5 位作者 Dan Wang Yingjiao Li Bao-chang Sun Yong Luo Guang-wen Chu Jian-feng Chen 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2022年第8期116-124,共9页
Microdroplets and their dispersion,with a large specific surface area and a short diffusion distance,have been applied in various unit operations and reaction processes.However,it is still a challenge to control the s... Microdroplets and their dispersion,with a large specific surface area and a short diffusion distance,have been applied in various unit operations and reaction processes.However,it is still a challenge to control the size and size distribution of microdroplets,especially for high-throughput generation.In this work,a novel ultra-high speed rotating packed bed(UHS-RPB)was invented,in which rotating foam packing with a speed of 4000-12000 r·min^(-1) provides microfluidic channels to disperse liquid into microdroplets with high throughput.Then generated microdroplets can be directly dispersed into a continuous falling film for obtaining a mixture of microdroplet dispersion.In this UHS-RPB,the effects of rotational speed,liquid initial velocity,liquid viscosity,liquid surface tension and packing pore size on the average size(d_(32))and size distribution of microdroplets were systematically investigated.Results showed that the UHS-RPB could produce microdroplets with a d_(32) of 25-63μm at a liquid flow rate of 1025 L·h^(-1),and the size distribution of the microdroplets accords well with Rosin-Rammler distribution model.In addi-tion,a correlation was established for the prediction of d_(32),and the predicted d_(32) was in good agreement with the experimental data with a deviation within±15%.These results demonstrated that UHS-RPB could be a promising candidate for controllable preparation of uniform microdroplets. 展开更多
关键词 ultra-high speed rotating packed bed MICRODROPLET Controllable preparation High throughput
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High speed laser cladding as a new approach to prepare ultra-high temperature ceramic coatings
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作者 Qiyao Deng Pengfei He +8 位作者 Chuan Sun Yang Li Yue Xing Yujie Wang Jinglong Li Xiubing Liang Xin Wang Yujie Zhou Yujun Cai 《Journal of Advanced Ceramics》 SCIE EI CAS CSCD 2024年第2期143-154,共12页
Ultra-high temperature ceramic(UHTC)coatings are used to protect the hot-end components of hypervelocity aerocrafts from thermal ablation.This study provides a new approach to fabricate UHTC coatings with high speed l... Ultra-high temperature ceramic(UHTC)coatings are used to protect the hot-end components of hypervelocity aerocrafts from thermal ablation.This study provides a new approach to fabricate UHTC coatings with high speed laser cladding(HSLC)technology,and places more emphasis on investigating the formation mechanism,phase compositions,and mechanical properties of HSLC-UHTC coatings.Results show that a well-bonded interface between the coating and the tantalum alloy substrate can be formed.The coating is mainly composed of(Zr,Ta)C ceramic solid solution phase with a content of higher than 90% by volume and Ta(W)metal solid solution phase.At a relatively high powder feeding rate,the ZrC ceramic phase appears in the coating while a dense ZrC UHTC top layer with a thickness of up to~50μm is successfully fabricated.As for the mechanical properties of the HSLC coatings,the fracture toughness of the coating decreases with the increase of powder feeding rate.The increase of carbide solid solution phase can significantly improve the high temperature microhardness(552.7±1.8 HV0.5@1000℃).The innovative design of HSLC ZrC-based coatings on refractory alloys accomplishes continuous transitions on microstructure and properties from the substrate to the UHTC top layer,which is a very promising candidate scheme for thermal protection coating. 展开更多
关键词 high speed laser cladding(HSLC) ultra-high temperature ceramic(UHTC) thermal protection coating microstructure mechanical properties
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湍流场中物质微元的形态特征及相应的模型 被引量:14
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作者 李希 陈建峰 陈甘棠 《力学学报》 EI CSCD 北大核心 1994年第3期266-274,共9页
运用高速显微摄影方法对10 ̄1…10 ̄3um尺度上的微观混和过程进行了实验观察,将物质微元的形态特征归结为片状与条状两类。在此基础上,提出了片状结构模型,将微观混和描述为片状微元上的收缩变形与分子扩散。分析表明,由于... 运用高速显微摄影方法对10 ̄1…10 ̄3um尺度上的微观混和过程进行了实验观察,将物质微元的形态特征归结为片状与条状两类。在此基础上,提出了片状结构模型,将微观混和描述为片状微元上的收缩变形与分子扩散。分析表明,由于变形与扩散之间的相互作用,微元上分子扩散区的宽度将趋于某一尺度δ=12λB,从而使微元体积呈指数增长,v~exp(sf).微观混和对化学反应的影响可用Damk6hler数Da来表征,模型能够正确模拟这种影响。 展开更多
关键词 湍流 微观混和 流场 流体力学
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磁驱动飞片的超高速激光阴影扫描摄影技术 被引量:3
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作者 汪伟 王桂吉 +2 位作者 罗振雄 莫建军 尚长水 《光学精密工程》 EI CAS CSCD 北大核心 2012年第5期927-933,共7页
针对磁驱动飞片的物理过程,设计了显微装置和激光阴影照明装置。结合超高速转镜式扫描相机,利用串联式光电开关避免相机像面重复曝光,有效地解决了飞片被碰撞过程中严重影响测试结果的自发强光现象,获得了磁驱动加载下飞片运动过程清晰... 针对磁驱动飞片的物理过程,设计了显微装置和激光阴影照明装置。结合超高速转镜式扫描相机,利用串联式光电开关避免相机像面重复曝光,有效地解决了飞片被碰撞过程中严重影响测试结果的自发强光现象,获得了磁驱动加载下飞片运动过程清晰的一维扫描试验图像。图像分析数据表明,在充电电压为60~64kV时,可将尺寸为8mm×6mm×0.7/0.9mm的Ly12铝飞片发射至9~14km/s的超高速度,且飞片运动速度与充电电压和飞片厚度有关。该项工作为磁驱动飞片运动过程的研究提供了一种重要的测试手段,其测试方法也适用于其它产生强烈杂光的高速碰撞的测试研究。 展开更多
关键词 高速显微摄影 阴影扫描摄影 激光照明 磁驱动 高速飞片
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金属切削变形与显微高速摄影分析
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作者 吴惠贞 陈子文 +1 位作者 柳景图 刘家齐 《光子学报》 EI CAS CSCD 1993年第4期346-351,共6页
运用显微高速摄影技术分析了切削过程中金属显微组织塑性变形规律。结果指出,切削中金属晶粒变形具有不均匀性和多晶体变形协调性,以晶粒为单元发生了波浪式起伏立体型变化,但受到晶界的制约。
关键词 金属切削 高速摄影 显微摄影 变形
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Optimization of submerged entry nozzle parameters for ultra-high casting speed continuous casting mold of billet 被引量:2
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作者 Pei Xu Yong-zhi Zhou +2 位作者 Deng-fu Chen Mu-jun Long Hua-mei Duan 《Journal of Iron and Steel Research International》 SCIE EI CSCD 2022年第1期44-52,共9页
Controlling the flow behavior in the mold in an appropriate way is the basis for realizing the billet ultra-high speed continuous casting.Based on the new proposed physical water modeling experiment considering the ef... Controlling the flow behavior in the mold in an appropriate way is the basis for realizing the billet ultra-high speed continuous casting.Based on the new proposed physical water modeling experiment considering the effects of solidified shell and hydrostatic pressure,the flow behavior in the mold with cross section of 160 mm 9160 mm during continuous casting of billet is regulated by optimizing the inner diameters and immersion depths of submerged entry nozzle at the ultra-high casting speeds of 5.0–6.5 m/min.The results show that under the premise of no slag entrainment,as well as uniform coverage and keeping good fluidity of liquid slag layer on the top free surface of the fluid in the mold,the appropriate parameters of submerged entry nozzle under the ultra-high casting speed of billet are 50 mm in inner diameter,95 mm in outer diameter and 180 mm in immersion depth.And on the basis of the obtained parameters of submerged entry nozzle,it can be known that the reasonable ranges of level fluctuation and impacting depth of the stream in the mold are about 0.82-1.11 and 593-617 mm,respectively. 展开更多
关键词 ultra-high casting speed Billet continuous casting Submerged entry nozzle Physical water modeling Flow behavior
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研究金属切削中组织变化的网格高速摄影装置
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作者 台伟 刘家齐 《高速摄影与光子学》 CSCD 1989年第2期131-138,共8页
研究金属切削过程中的变化,对改进切削工艺、实现高速、自动化和精密加工具有重要意义。高速显微摄影是实现从宏观到微观、从定性到定量、从静态到动态研究的有效方法。 为了上述目的,我们研制了一台网格显微高速摄影装置,其主要参数为:... 研究金属切削过程中的变化,对改进切削工艺、实现高速、自动化和精密加工具有重要意义。高速显微摄影是实现从宏观到微观、从定性到定量、从静态到动态研究的有效方法。 为了上述目的,我们研制了一台网格显微高速摄影装置,其主要参数为: 放大倍率:50X 视场:1.2×1.2mm^2 拍摄频率:10~3~10~5fps 目前已完成了显微系统与网格摄影系统的光学匹配,解决了显微网格高速摄影中的一些特殊问题,并对图象还原问题进行了研究。利用该装置为华侨大学进行了实际拍摄,取得了令人满意的结果。 展开更多
关键词 金属切削 显微摄影 网格摄影
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Design and Key Technology of Oil-Free Centrifugal Air Compressor for Hydrogen Fuel Cell 被引量:3
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作者 Hongjie Zhang Wenfei Yu Wei Hua 《CES Transactions on Electrical Machines and Systems》 CSCD 2022年第1期11-19,共9页
For a 120 kW hydrogen fuel cell system,a centrifugal air compressor with fixed power of 22 kW fuel cell is designed.Firstly,the theoretical calculation is carried out for the aerodynamic characteristics of a ultra-hig... For a 120 kW hydrogen fuel cell system,a centrifugal air compressor with fixed power of 22 kW fuel cell is designed.Firstly,the theoretical calculation is carried out for the aerodynamic characteristics of a ultra-high-speed permanent magnet synchronous motor,an air compressor,and an aerodynamic foil bearing.Then,a prototype is trial-produced and a related test bench is built for test verification.Finally,both the simulation and test results indicate that the designed centrifugal air compressor meets the overall requirements of the hydrogen fuel cell system,and the relevant conclusions provide both theoretical and experimental references for the subsequent series development and design of the centrifugal air compressor. 展开更多
关键词 Hydrogen fuel cell Centrifugal air compressor ultra-high speed permanent magnet synchronous motor Compressor impeller Air pressure foil bearing
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Ultra-high speed holographic shape and displacement measurements in the hearing sciences
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作者 Haimi Tang Pavel Psota +2 位作者 John J.Rosowski Cosme Furlong Jeffrey Tao Cheng 《Light(Advanced Manufacturing)》 2022年第2期1-14,共14页
The auditory system of mammals enables the perception of sound from our surrounding world.Containing some of the smallest bones in the body,the ear transduces complex acoustic signals with high-temporal sensitivity to... The auditory system of mammals enables the perception of sound from our surrounding world.Containing some of the smallest bones in the body,the ear transduces complex acoustic signals with high-temporal sensitivity to complex mechanical vibrations with magnitudes as small as tens of picometers.Measurements of the shape and acoustically induced motions of different components of the ear are essential if we are to expand our understanding of hearing mechanisms,and also provide quantitative information for the development of numerical ear models that can be used to improve hearing protection,clinical diagnosis,and repair of damaged or diseased ears.We are developing digital holographic methods and instrumentation using an ultra-high speed camera to measure shape and acoustically-induced motions in the middle ear.Specifically we study the eardrum,the first structure of the middle ear which initializes the acoustic-mechanical transduction of sound for hearing.Our measurement system is capable of performing holographic measurement at rates up to 2.1 M frames per second.Two shape measurement modalities had previously been implemented into our holographic systems:(1)a multi-wavelength method with a wavelength tunable laser;and(2)a multi-angle illumination method with a single wavelength laser.In this paper,we present a third method using a miniaturized fringe projection system with a microelectromechanical system(MEMS)mirror.Further,we optimize the processing of large data sets of holographic displacement measurements using a vectorized Pearson's correlation algorithm.We validate and compare the shape and displacement measurements of our methodologies using a National Institute of Standards and Technology(NIST)traceable gauge and sound-activated latex membranes and human eardrums. 展开更多
关键词 ultra-high speed digital holography Microelectromechanical systems(MEMS) Miniaturized Fringe Projection Middle-ear mechanics Shape and displacement measurements.
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Time amplifying techniques towards atomic time resolution 被引量:5
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作者 LI JingZhen Institute of Photonic Engineering,College of Electron Science&Technology,Shenzhen University,and Shenzhen Key Laboratory of Micro·Nano Photonic Information,Shenzhen 518060,China 《Science China(Technological Sciences)》 SCIE EI CAS 2009年第12期3425-3446,共22页
High speed imaging technology has opened applications in many fields,such as collision,detonating, high voltage discharge,disintegration and transfer of phonon and exciton in solid,photosynthesis primitive reaction,an... High speed imaging technology has opened applications in many fields,such as collision,detonating, high voltage discharge,disintegration and transfer of phonon and exciton in solid,photosynthesis primitive reaction,and electron dynamics inside atom shell.In principle,all of the transient processes need to be explained theoretically and,at the same time,the time amplifying technique is required for observations of these processes.The present review concerns the atomic time amplifying mechanism of optical information and the extremely-high speed imaging methods,which are expressed in terms of the short time amplifying techniques.It is well-known that for extremely-high speed imaging with the converter tube,the temporal resolution is in the order of sub-picosecond of the streak imaging,and the imaging frequency is 6×10 8 ―5×10 9 fps(frame per second)of the frame imaging.On the other hand,for the tubeless extremely-high speed imaging,the imaging frequency is 10 7 ―10 14 fps,and its mechanism of forming high speed and framing could involve a lot of factors of the light under investigation,for instance,light speed,light parallelism,the parameters of light wave such as amplitude,phase,polari- zation and wavelength,and even quantum properties of photon.In the cascaded system of electro- magnetic wave and particle wave,it is possible to simultaneously realize extremely-high resolution in time and space,which is higher than a kite resolution.Then it would be possible to break the limit of the Heisenberg uncertainty relation of the optical frequency band. 展开更多
关键词 TIME amplification image converter tube IMAGING TUBELESS IMAGING ultra-high speed IMAGING extremely-high speed IMAGING holog- raphic coherent SHUTTER optical acceleration
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Performance of waterjet on cutting maize stalks: A preliminary investigation 被引量:1
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作者 Hongnan Hu Hongwen Li +4 位作者 Qingjie Wang Jin He Caiyun Lu Yingbo Wang Chunlei Wang 《International Journal of Agricultural and Biological Engineering》 SCIE EI CAS 2019年第5期64-70,共7页
Large amounts of crop stalks left in the field as a result of conservation agriculture cause blockage during no-till planting.To solve this issue,pure waterjet was used to cut off the maize stalks so that the rear fur... Large amounts of crop stalks left in the field as a result of conservation agriculture cause blockage during no-till planting.To solve this issue,pure waterjet was used to cut off the maize stalks so that the rear furrow opener could pass through without blockage.In this investigation,an experimental study on depth of cut,which was the main performance indicator of pure waterjet on cutting maize stalks,was presented.A full factorial design with 200 tests was implemented with respect to three operation parameters,that is traverse speed,waterjet pressure,and standoff distance were considered as variables.An analysis of variance(ANOVA)was carried out in order to determine the statistical significance of individual operation parameters.Using multilinear stepwise regression analysis,a model to predict the cut of depth from the predicted pure waterjet operation to cut maize stalks was then developed.All three operation parameters significantly influenced the cutting performance.Moreover,the results indicated that depth of cut increased with the increase of waterjet pressure,the decrease of traverse speed,and decrease in standoff distance.Waterjet pressure provided major contribution to depth of cut,followed by traverse speed,then standoff distance,which was demonstrated by both ANOVA and regression analysis.The experimental results showed that when the standoff distance was closer than 10 mm and waterjet pressure was 280 MPa,all maize stalks specimen could be cutoff thoroughly.With the consideration of field operating conditions,waterjet pressure of 280 MPa or higher and 10 mm to 15 mm standoff distance were recommended for maize stalks cutting.This analysis provided a realistic approach for the optimization of the ultra-high pressure pure waterjet parameters in maize stalks cutting,which could be used to relieve the occurrence of straw blockage in no-till planting. 展开更多
关键词 waterjet ultra-high pressure conservation tillage maize stalks CUTTING traverse speed standoff distance
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