Formation and solving for the micro-waves of fly-cut surface introduced by spindle error

为分析超精密飞切机床加工表面微波纹的形成机理,研究了主轴回转误差信息提取与表面形貌仿真技术,获取微波纹误差来源并研究解决方案。首先,在超精密飞切机床主轴上搭载五通道在线电容位移检测系统,并对采集到的信号进行误差分析提取。然后,建立飞切加工表面微观形貌三维仿真模型,仿真分析主轴误差引入的加工表面微波纹,并与表面检测结果比对确定误差来源。最后,通过调整主轴电机控制系统抑制该误差。三维仿真和实测结果相吻合,证实超精密飞切机床主轴转速波动导致的回转误差造成了工件表面1 Hz左右的规律性条纹,对主轴转速控制系统进行数字化改造后,基本消除了该因素导致的表面微波纹,表面粗糙度从5 nm以上抑制到2 nm左右,PV值优于10 nm。超精密飞切机床主轴转速波动会对飞切加工表面微观形貌以及表面粗糙度产生显著影响,需至少控制在0.5 r/min以内。In order to find out the formation mechanism of micro-waves on the fly-cut surface,the spindle motion error was sampled and a 3D topography simulation model was compiled. Firstly,a nano-class testing and evaluation system was established on the fly cutting machine,the displacement data was sampled and the spindle motion error was analyzed.Then a 3D surface profile topography simulation model was established to analyze the micro-waves caused by the spindle motion error. The simulated surface was compared with the measured surface to find out the error sources. Finally,the characteristics of spindle were improved by adjusting the control system of the spindle motor. The simulated 3D surface profile topography was similar to that of the measured profile,which verified that the macro-waves was caused by the undulate of the spindle speed. When the spindle characteristics was improved,the macro-waves caused by the spindle motion error almost disappeared,and the surface roughness reduced from more than 5 nm to 2 nm. It is thus concluded that the undulate of ultra-precision fly cutting machine spindle speed causes macro-waves on the work-piece surface,and the undulate spindle speed must less than 0. 5 r / min.基金项目:高档数控机床与基础制造装备《强激光光学元件超精密制造关键装备研制》(2013ZX04006011-102-001

“一带一路”视角下东南亚职业型人才培养模式分析

在"一带一路"倡议推动以来,中国与东南亚各国在贸易及建设上有着更紧密的合作,在开展合作的过程中对于双方在各行各业的人才有着莫大的需求。由于国情不同,加上重大项目所涉略的领域过广,不论是中国或是东南亚国家都出现人才短缺的问题,所以当务之急是培养一批适用于双方的人才。此文梳理了东南亚各国与中国在各方面的关系,找出东南亚各国在人才培养方面所存在的问题,借鉴德国双元制教育模式来对东南亚职业型人才进行有针对性的培养

On-line measurement and evaluation of spindle error motion in ultra precision machine tool

为了实现对超精密机床主轴回转误差的在线测试与评价,建立了纳米级在线测试与评价系统。对该系统所采用的测试仪器、干扰抑制、数据处理与指标评价方法进行研究。首先,在某台超精密切削机床上搭建了由5个电容传感器组成的5通道测试模块。接着,以多通道高速数据采集模块实现多通道位移数据模拟量的高速采集。然后,对采集的信号进行必要的干扰信号分离。最后,将5通道位移数据转换为易于理解的轴向误差和径向误差数据,并按照同步误差和异步误差进行分离。测试结果表明:该机床主轴工作转速下的径向同步误差为405 nM,径向异步误差为66 nM;轴向同步误差为59 nM,轴向异步误差为54 nM。能够实现超精密机床主轴回转误差的纳米级在线测试,对于超精密光学加工表面的误差溯源和机床主轴性能分析具有重要意义。In order to realize the on-line measurement and analysis of spindle error motion in ultra precision machine,a nano-class testing and evaluation system is established and its measurement instruments,interference control,data processing,evaluation methods and etc.are investigated.Firstly,a five-channel module consisted of five capacitance sensors is established on an ultra precision cutting machine.All the five channels of the displacement sensors are sampled via a high speed data acquisition system simultaneously.Secondly,the separation of interference signals from displacement sensors has been carried out.Finally,the displacement signals are transformed into radial error and axial error,and are separated as synchronous and asynchronous error.Experimental results indicate that the synchronous error and the asynchronous error in radial direction are 405 nm and 66 nm respectively,and the synchronous error and the asynchronous error in axial direction are 59 nm and 54 nm respectively.It can meet the system demands of nano-class,on-line measurement of ultra precision spindle.Thus,it is of great importance for the optical work piece's surface error tracing,and the spindle's performance analyzing.高档数控机床与基础制造装备“强激光光学元件超精密制造关键装备研制”(2013ZX04006011-102-001

Separation and purification of catalpol from Radix Rehmanniae

An ultrasonic extraction technology of preparing catalpol from Radix Rehmanniae was optimized by a uniform experimental design.The optimum conditions for ultrasonic extraction were thus established: 68% (vol) ethanol aqueous solution as extraction solvent,the volume(ml) to mass(g) ratio of extraction solvent to feed of 5∶1,the ultrasonic treatment time of 36 min.The crude catalpol obtained from the optimized ultrasonic extraction technology was further purified by selective adsorption with macroporous resin.The adsorption capacities and desorption yields of ten kinds of macroporous resins for catalpol were investigated.The results showed that H103 resin possessed the best performance.The properties of dynamic adsorption and desorption of H103 resin for catalpol were subsequently investigated on adsorption column.The optimum conditions for adsorption and desorption were determined.The concentration of catalpol in the loaded sample solution was 6.15 mg·ml-1,the flow rate was 1.0 ml·min-1,the volumetric percentage of ethanol in the eluting solvent was 75%,the elution flow rate was 0.5 ml·min-1 and the elution volume was 3.33 BV(bed volume).Under the above conditions,the purity of catalpol product eluted from the column packed with H103 resin reached 62.39% while that of the crude catalpol was only 10.01%

Numerical Simulation of Transportation of Marine Microplastics: A Review

The temporal and spatial discontinuity of microplastic sampling data restricts the investigation on their source,sink,transport pathway and trend. Numerical simulation combined with sampling investigation can comprehensively study the effects of microplastic characteristics,meteorology and hydrodynamics on the distribution and transportation of microplastics. In this paper,the studies of microplastic numerical simulation were reviewed from the aspects of numerical simulating research and their applications in microplastic tranportation,and the results were summarized as follows:The construction of the main driving force(current); the influence of environmental factors,such as wind,waves,topography and extreme sea conditions on the properties of microplastics with different characteristics(particle size,density,shape)and their tranportation; the application of numerical simulation in the study of microplastic removal. Based on progress on the study of numerical simulation of marine microplastics,the future directions were pointed out that the further simulating studies should focuson the spatio-temporal distribution and evolvement of microplastics by combining sampling data and numerical model, the simulating research on the relationship between microplastic parameters (roughness,wind drag coefficient,settling rate,resuspension rate and biofouling rate)and(meteorological and ocean)dynamic condition. Moreover,the results of simulating sensitivity experiments should be compared with sampling and laboratory testing data to improve the empirical parameters and formulas of numerical model.</p