Anti-tension technology of slipway in long-stroke horizontal vibration table

为了解决长行程水平向振动台中管线对滑台牵拉引起的输出波形失真问题,提出一种带动管线跟踪滑台同步运动的随动装置设计方法.建立管线牵拉力作用下的水平向振动台机电耦合动力学模型,计算管线牵拉力对振动台输出波形失真度的影响;设计一种基于光栅尺的滑台随动装置,带动随动平台与滑台做同步运动,滑台上的管线经随动平台后引出,此时管线的牵拉力直接作用在随动平台上,而滑台上受到的牵拉力趋于零.试验结果表明,通过增设滑台随动装置,水平向振动台在做超低频大行程振动时的输出波形失真度得到极大的改善.In order to solve the problem of output waveform distortion due to the pipes and wires' tension in a long-stroke horizontal vibration table,a follow-up-gear design technology was put forward which drove the pipes and wires to move synchronously with the slipway.The electromechanical coupling kinetic model of a horizontal vibration table was analyzed considering the tension of pipes and wires in it,and the influences of tension forces of the pipes and wires on the output waveform distortion of the horizontal vibration table was calculated.A follow-up gear for the slipway was developed based on a precise linear encoder,and drove a following table moving synchronously with the slipway.And the pipes and wires on the slipway were led out through the following table,on which the tension forces directly acted,but the tension force on the slipway drove to zero.The experimental results indicate that the output waveform distortion improves greatly after adding the follow-up gear when the horizontal vibration table works in long-stroke and ultra-low-frequency motion.新世纪优秀人才支持计划资助项目(NCET-08-0494);浙江省“钱江人才计划”资助项目(2009R10026);浙江省重点科技创新团队建设资助项目(2009R50008

Improving the performance of IPMCs with a gradient in thickness

Natural Science Foundation of Fujian Province of China [2011J05140]; Fundamental Research Funds for Central Universities of Xiamen University [2011121045]An ionic polymer metal composite (IPMC) is a kind of electro-active polymer. Due to the properties of low driving voltage, large deformation, flexibility and lightness, it is becoming one of the more popular from a diversity of smart materials. In this study, a novel structure of Nafion (R) film is proposed to improve the performance of an IPMC. IPMC samples with a gradient structure in thickness are fabricated and their performance is investigated to confirm the validity of the gradient structure. The deformation displacement and the blocking force are compared under AC and DC voltage by experiments. The results indicate that the structure of gradient in thickness would improve the performance both in deformation displacement and blocking force

Time-resolved PL Spectra Study of Ordered Ga_(0.52)In_(0.48)P Alloys

【中文摘要】 在室温和低温液氮下 ,研究了有序和无序 Ga0 .52 In0 .4 8P的时间分辨发光谱。对实验结果的拟合表明 ,有序 Ga0 .52 In0 .4 8P的发光呈双指数规律衰退。其中快过程对应着有序区域上载流子的复合 ,慢过程则对应着有序区域和无序区域的空间分离中心上载流子的复合。无序 Ga0 .52 In0 .4 8P的发光在室温下呈单指数规律衰退。同时从低温下的时间分辨发光谱还可以看出有序样品的发光峰随着延迟时间的变长而蓝移 ,说明低温下在有序 Ga0 .52In0 .4 8P中存在着载流子从无序区域到有序区域的转移 【英文摘要】 The time resolved photoluminescence(TRPL) spectra of ordered and disordered Ga 0.52 In 0.48 P alloys grown by MOVPE were investigated.The least square fitting of the luminescence decay spectra of ordered alloys shows that there exist two exponential processes:The short lifetime process was corresponding to the high energy peak in PL spectra which is attributed to the recombination of the carriers in the ordered domains and the long lifetime process was corresponding to the low energy peak in the P...国家自然科学基金 (编号:69776011); 福建省自然科学基金 (编号:A9910004和 A0110007

Electrohydrodynamic direct-writing of conductor-insulator-conductor multi-layer interconnection

Key Program of the National Natural Science Foundation of China [51035002]; National Natural Science Foundation of China [51305373]; Specialized Research Fund for the Doctoral Program of Higher Education of China [20120121120035]A multi-layer interconnection structure is a basic component of electronic devices, and printing of the multi-layer interconnection structure is the key process in printed electronics. In this work, electrohydrodynamic direct-writing (EDW) is utilized to print the conductor-insulator-conductor multi-layer interconnection structure. Silver ink is chosen to print the conductor pattern, and a polyvinylpyrrolidone (PVP) solution is utilized to fabricate the insulator layer between the bottom and top conductor patterns. The influences of EDW process parameters on the line width of the printed conductor and insulator patterns are studied systematically. The obtained results show that the line width of the printed structure increases with the increase of the flow rate, but decreases with the increase of applied voltage and PVP content in the solution. The average resistivity values of the bottom and top silver conductor tracks are determined to be 1.34 x 10(-7) Omega.m and 1.39 x 10(-7) Omega.m, respectively. The printed PVP layer between the two conductor tracks is well insulated, which can meet the insulation requirement of the electronic devices. This study offers an alternative, fast, and cost-effective method of fabricating conductor-insulator-conductor multi-layer interconnections in the electronic industry

Electrohydrodynamic direct - Writing of conductor - Insulator-conductor multi-layer interconnection

A multi-layer interconnection structure is a basic component of electronic devices, and printing of the multi-layer interconnection structure is the key process in printed electronics. In this work, electrohydrodynamic direct-writing (EDW) is utilized to print the conductor - insulator - conductor multi-layer interconnection structure. Silver ink is chosen to print the conductor pattern, and a polyvinylpyrrolidone (PVP) solution is utilized to fabricate the insulator layer between the bottom and top conductor patterns. The influences of EDW process parameters on the line width of the printed conductor and insulator patterns are studied systematically. The obtained results show that the line width of the printed structure increases with the increase of the flow rate, but decreases with the increase of applied voltage and PVP content in the solution. The average resistivity values of the bottom and top silver conductor tracks are determined to be 1.34 × 10-7 Ω·m and 1.39 × 10-7 Ω·m, respectively. The printed PVP layer between the two conductor tracks is well insulated, which can meet the insulation requirement of the electronic devices. This study offers an alternative, fast, and cost-effective method of fabricating conductor - insulator - conductor multi-layer interconnections in the electronic industry. ? 2014 Chinese Physical Society and IOP Publishing Ltd

Measurement of Non-uniform Residual Stresses by Incremental Hole-Drilling Method

针对传统的小孔法只能测量试件内沿深度方向均匀分布的残余应力,采用逐层钻孔的小孔法测量试件中的非均匀残余应力,通过有限元法标定计算校准系数矩阵,构建了一种实用的非均匀应力测试技术。首先,用AnSyS软件构造试件和应变花粘贴的三维有限元模型,采用分层加载的办法实现各层校准系数的仿真计算,标定计算出钻孔深度达到H=0.5d使应力完全释放时,用5步逐层钻孔法构造5层不均匀应力所需的校准系数矩阵;然后,利用标定出的校准系数矩阵,采用5步逐层钻孔的实验方法,测量构建Cr12MOV淬火件的5层非均匀残余应力,并与传统的小孔法进行测试比对。结果表明:用有限元仿真的方法可以模拟试件中的非均匀残余应力场,用于标定计算测量所需的校准系数矩阵;通过5步逐层钻孔实验测量,可以构建出Cr12MOV淬火件的5层不均匀残余应力。While conventional hole-drilling methods can only measure uniform residual stresses along a specimen′s depth,an incremental hole-drilling method is used to measure non-uniform residual stresses inside a specimen.The calibration constants matrix is calculated using the finite element calibration method,and a practical measurement technology of non-uniform stress is established.An agglutinate 3-D finite element model of a specimen with rosette is built using ANSYS software,and the calibration constants in each layer are calculated with a dividing-layer loading method.The calibration constants matrix is obtained when the hole depth reaches h=0.5 Dto completely release residual stresses,and is used to form the fivelayer non-uniform stresses with the five-step hole-drilling method.Then,the five-step incremental holedrilling method and the calculated calibration constants matrix are used to experimentally measure the nonuniform residual stresses within the Cr12 MoV quenching specimens.Comparing these measurements with the results of conventional hole-drilling methods shows that the finite element calibration method can simulate non-uniform residual stresses field inner specimen to calculate the calibration constants matrix.In addition,the five-step incremental hole-drilling results show that the five-layer non-uniform residual stresses can be built up in Cr12 MoV quenching specimens.高等学校博士学科点专项科研基金资助项目(20120121120036); 国家自然科学基金资助项目(50675200

Eliminating residual stress in 45 steel quenching specimens by electrical pulse

为了研究电脉冲消除金属材料内部残余应力的效果,通过储能电容器放电产生高能电脉冲,对淬火后的45优质碳素结构钢冷轧薄板件进行放电处理,采用小孔法测定电脉冲处理前后试样内残余应力的变化规律.用于电脉冲处理的脉冲电流为指数衰减的振荡波形,同时满足第一个主峰的电流密度为12.2kA/MM2,单次处理的振荡脉冲持续时间小于0.8MS.试验结果表明,经过电脉冲处理后,45钢淬火件中2个主方向残余应力的幅值均出现较为显著的降低,且两者都出现均化效果.In order to investigate the effect of electrical pulse on eliminating residual stress within metallic material,high-energy electrical pulse was generated by discharging with energy-storage capacitors,and was adopted to treat quenching cold-rolled sheet specimens that were made of 45 high-quality carbon structural steel,and the hole-drilling method was taken to determine the change rule of the residual stress within the specimens before and after electropulse treatment.The pulse current used for electropulse treatment had oscillating waveshape with exponential damping,whose first peak of the current density was 12.2 kA/mm2 and oscillating pulse duration of single treatment was less than 0.8ms.The experimental results show that the amplitude of residual stresses in the two principal directions of 45 steel quenching specimens decrease much more significantly after electropulsing treatment and both of them are homogenized.国家自然科学基金资助项目(50675200);中央高校基本科研业务费专项资金资助项目(2009QNA4002);浙江省重点科技创新团队建设项目资助项目(2009R50008

Closed loop dynamic fuzzy neural network for real-time lifetime forecasting

Conference Name:2013 3rd International Conference on Materials and Products Manufacturing Technology, ICMPMT 2013. Conference Address: Guangzhou, China. Time:September 25, 2013 - September 26, 2013.Real-time lifetime forecasting has extensive application in the fields of machine system manufacturing and integration, which is a good way to promote the dependability and operation stability. In this paper, a closed loop adaptive forecasting model with feedback channel of state monitoring information is built up for the real-time lifetime forecasting. The difference of working state between prediction and monitoring information is used to evaluate the prediction performance. The dynamic fuzzy neural network introduced into the prediction model, in which the fuzzy rule, membrane function and structure parameters can be adjusted according to the evaluate results. A service lifetime testing experiment of gear case is utilized to validate the prediction model. The proposed model achieved reasonable precision with an error of less than 1 hour between the failure time of experimental results and the forecasting remaining lifetime. The adaptive prediction method can deal with the real-time lifetime forecasting for multiple factors and nonlinear system without specific parameters structure. ? (2014) Trans Tech Publications, Switzerland

Precision deposition of micro/nano pattern printed by electrohydrodynamic direct-write

研究了利用电纺直写技术进行图案化微纳结构可控喷印沉积的方法,该方法利用喷头与收集板之间的稳定直线射流来实现有序纳米纤维的直写制造。分析了电纺直写射流在静止收集板和移动收集板上的沉积行为;探究了工艺参数对电纺直写微纳结构定位误差的影响规律。实验显示:在内部应力和电荷排斥力的作用下,射流会产生弯曲螺旋从而引导纳米纤维在静止收集板上逐层叠加形成三维微结构;提高收集板运动速度可克服射流螺旋鞭动,获得无螺旋结构的直线纳米纤维。根据设计图形分别电纺直写了方波、多圈矩形纳米纤维图案,分析了直写图案尺寸与设计图案尺寸间的误差。结果显示:电纺直写纤维图案定位误差随着收集板运动速度、喷头至收集板距离、施加电压、收集板运动距离的升高而增加;优化实验条件和试验参数,电纺直写微纳结构定位误差可优于10μm。实验验证了微纳结构图案的精确喷印沉积有助于提高电纺直写技术的控制水平。The precision deposition of micro/nano patterns printed by Electrohydrodynamic Direct Writing(EDW)technology was explored and the EDW for orderly nanofibers was implemented by the straight stable jet between a spinneret and a collector.The deposition behaviors of EDW jet on stationary and moving substrates were investigated.The effects of process parameters on the position errors of EDW patters were also studied.The experiments show that the jet is bended into a spiral structure by the inner stress and charge repulse force,and then the nanofiber is guided to form a three-dimensional fibrous microstructure on the stationary substrate.By increasing the velocity ofcollector,the bending process of charged jet can be overcome and the straight line nanofiber without spiral coil is direct-written on the substrate.The multi rectangle wave and square wave nanofibrous patterns are direct-written according to the designed pattern,respectively,and the dimension error between the direct-written nanofibrous pattern and designed pattern is also analyzed.The results indicates that the position error of direct-written nanofibrous pattern increases with increasing the velocity of collector,the distance between spinneret and collector,applied voltage,and the motion distance of collector.Moreover,by optimizing the experimental conditions and design parameters,the position error of direct-written fibrous pattern can be less than 10μm.It concludes that the precision deposition of micro/nano pattern is benefit to promoting the control level of EDW technology.国家自然科学基金资助项目(No.51305373);; 发光材料与器件国家重点实验室开放基金资助项目(No.2015-skllmd_03);; 中央高校基本科研业务费专项资金资助项目(No.20720150082);; 广东省前沿与关键技术创新专项资金(省重大科技专项)(No.2015B010124001

Eliminating residual stress in 45 steel quenching specimens by electrical pulse

In order to investigate the effect of electrical pulse on eliminating residual stress within metallic material, high-energy electrical pulse was generated by discharging with energy-storage capacitors, and was adopted to treat quenching cold-rolled sheet specimens that were made of 45 high-quality carbon structural steel, and the hole-drilling method was taken to determine the change rule of the residual stress within the specimens before and after electropulse treatment. The pulse current used for electropulse treatment had oscillating waveshape with exponential damping, whose first peak of the current density was 12.2 kA/mm2 and oscillating pulse duration of single treatment was less than 0.8ms. The experimental results show that the amplitude of residual stresses in the two principal directions of 45 steel quenching specimens decrease much more significantly after electropulsing treatment and both of them are homogenized