Double-sided lapping is an precision machining method capable of obtaining high-precision surface.However,during the lapping process of thin pure copper substrate,the workpiece will be warped due to the influence of r...Double-sided lapping is an precision machining method capable of obtaining high-precision surface.However,during the lapping process of thin pure copper substrate,the workpiece will be warped due to the influence of residual stress,including the machining stress and initial residual stress,which will deteriorate the flatness of the workpiece and ultimately affect the performance of components.In this study,finite element method(FEM)was adopted to study the effect of residual stress-related on the deformation of pure copper substrate during double-sided lapping.Considering the initial residual stress of the workpiece,the stress caused by the lapping and their distribution characteristics,a prediction model was proposed for simulating workpiece machining deformation in lapping process by measuring the material removal rate of the upper and lower surfaces of the workpiece under the corresponding parameters.The results showed that the primary cause of the warping deformation of the workpiece in the doublesided lapping is the redistribution of initial residual stress caused by uneven material removal on the both surfaces.The finite element simulation results were in good agreement with the experimental results.展开更多
This paper proposes a method combining blue the Haar wavelet and the least square to solve the multi-dimensional stochastic Ito-Volterra integral equation.This approach is to transform stochastic integral equations in...This paper proposes a method combining blue the Haar wavelet and the least square to solve the multi-dimensional stochastic Ito-Volterra integral equation.This approach is to transform stochastic integral equations into a system of algebraic equations.Meanwhile,the error analysis is proven.Finally,the effectiveness of the approach is verified by two numerical examples.展开更多
目的:系统评价坦索罗辛单用或联合抗胆碱能药物治疗输尿管支架相关症状(SRSs)的疗效,为临床治疗提供循证参考。方法:计算机检索Pub Med、Embase、Cochrane图书馆、中国期刊全文数据库、中国生物医学文献数据库、中文科技期刊数据库、万...目的:系统评价坦索罗辛单用或联合抗胆碱能药物治疗输尿管支架相关症状(SRSs)的疗效,为临床治疗提供循证参考。方法:计算机检索Pub Med、Embase、Cochrane图书馆、中国期刊全文数据库、中国生物医学文献数据库、中文科技期刊数据库、万方数据库,检索时限均为各数据库自建库起至2019年10月,收集坦索罗辛单药(单用组)或联合抗胆碱能药物(联用组)对比安慰剂或空白对照(对照组)治疗SRSs的随机对照试验(RCT),对符合纳入标准的临床研究进行资料提取后,采用Cochrane协作网系统评价手册5.1.0进行质量评价,采用Rev Man 5.3统计软件进行Meta分析。结果:共纳入9项RCT,合计932例患者。Meta分析结果显示,在支架置入术后,单用组患者尿路症状评分[MD=-4.23,95%CI(-5.96,-2.51),P<0.00001]、躯体疼痛评分[MD=-4.20,95%C(I-5.30,-3.10),P<0.00001]、总体健康评分[MD=-1.36,95%C(I-1.75,-0.98),P<0.00001]均显著低于对照组,差异均有统计学意义;两组患者工作能力评分[MD=0.19,95%CI(-0.99,1.37),P=0.76]、性生活质量评分[MD=-0.31,95%CI(-0.68,0.05),P=0.09]比较,差异均无统计学意义。支架取出后4周,单用组患者躯体疼痛评分[MD=-0.64,95%CI(-0.84,-0.43),P<0.00001]、总体健康评分[MD=-0.28,95%CI(-0.41,-0.15),P<0.0001]、尿路症状评分[MD=-1.46,95%C(I-2.60,-0.32),P=0.01]均显著低于对照组,差异均有统计学意义;而两组患者工作能力评分[MD=0.31,95%CI(-0.22,0.84),P=0.25]、性生活质量评分[MD=-0.15,95%C(I-0.41,0.10),P=0.23]比较,差异无统计学意义。单用组患者尿路症状评分[MD=5.93,95%CI(2.83,9.02),P=0.0002]、躯体疼痛评分[MD=3.49,95%CI(1.39,5.60),P=0.001]、总体健康评分[MD=2.96,95%CI(1.44,4.49),P=0.0001]均显著高于联用组;两组患者工作能力评分[MD=1.53,95%CI(-0.12,3.18),P=0.07]、性生活质量评分[MD=0.46,95%CI(-1.03,1.96),P=0.54]比较,差异均无统计学意义。结论:坦索罗辛对SRSs有较好的治疗作用,联合抗胆碱能药物能获得更好的治疗效果。展开更多
基金National Key Research and Development Program of China(Grant No.2018YFA0702900)Science Challenge Project of China(Grant No.TZ2016006)National Natural Science Foundation of China(Grant No.51975096)。
文摘Double-sided lapping is an precision machining method capable of obtaining high-precision surface.However,during the lapping process of thin pure copper substrate,the workpiece will be warped due to the influence of residual stress,including the machining stress and initial residual stress,which will deteriorate the flatness of the workpiece and ultimately affect the performance of components.In this study,finite element method(FEM)was adopted to study the effect of residual stress-related on the deformation of pure copper substrate during double-sided lapping.Considering the initial residual stress of the workpiece,the stress caused by the lapping and their distribution characteristics,a prediction model was proposed for simulating workpiece machining deformation in lapping process by measuring the material removal rate of the upper and lower surfaces of the workpiece under the corresponding parameters.The results showed that the primary cause of the warping deformation of the workpiece in the doublesided lapping is the redistribution of initial residual stress caused by uneven material removal on the both surfaces.The finite element simulation results were in good agreement with the experimental results.
基金Supported by the NSF of Hubei Province(2022CFD042)。
文摘This paper proposes a method combining blue the Haar wavelet and the least square to solve the multi-dimensional stochastic Ito-Volterra integral equation.This approach is to transform stochastic integral equations into a system of algebraic equations.Meanwhile,the error analysis is proven.Finally,the effectiveness of the approach is verified by two numerical examples.
文摘目的:系统评价坦索罗辛单用或联合抗胆碱能药物治疗输尿管支架相关症状(SRSs)的疗效,为临床治疗提供循证参考。方法:计算机检索Pub Med、Embase、Cochrane图书馆、中国期刊全文数据库、中国生物医学文献数据库、中文科技期刊数据库、万方数据库,检索时限均为各数据库自建库起至2019年10月,收集坦索罗辛单药(单用组)或联合抗胆碱能药物(联用组)对比安慰剂或空白对照(对照组)治疗SRSs的随机对照试验(RCT),对符合纳入标准的临床研究进行资料提取后,采用Cochrane协作网系统评价手册5.1.0进行质量评价,采用Rev Man 5.3统计软件进行Meta分析。结果:共纳入9项RCT,合计932例患者。Meta分析结果显示,在支架置入术后,单用组患者尿路症状评分[MD=-4.23,95%CI(-5.96,-2.51),P<0.00001]、躯体疼痛评分[MD=-4.20,95%C(I-5.30,-3.10),P<0.00001]、总体健康评分[MD=-1.36,95%C(I-1.75,-0.98),P<0.00001]均显著低于对照组,差异均有统计学意义;两组患者工作能力评分[MD=0.19,95%CI(-0.99,1.37),P=0.76]、性生活质量评分[MD=-0.31,95%CI(-0.68,0.05),P=0.09]比较,差异均无统计学意义。支架取出后4周,单用组患者躯体疼痛评分[MD=-0.64,95%CI(-0.84,-0.43),P<0.00001]、总体健康评分[MD=-0.28,95%CI(-0.41,-0.15),P<0.0001]、尿路症状评分[MD=-1.46,95%C(I-2.60,-0.32),P=0.01]均显著低于对照组,差异均有统计学意义;而两组患者工作能力评分[MD=0.31,95%CI(-0.22,0.84),P=0.25]、性生活质量评分[MD=-0.15,95%C(I-0.41,0.10),P=0.23]比较,差异无统计学意义。单用组患者尿路症状评分[MD=5.93,95%CI(2.83,9.02),P=0.0002]、躯体疼痛评分[MD=3.49,95%CI(1.39,5.60),P=0.001]、总体健康评分[MD=2.96,95%CI(1.44,4.49),P=0.0001]均显著高于联用组;两组患者工作能力评分[MD=1.53,95%CI(-0.12,3.18),P=0.07]、性生活质量评分[MD=0.46,95%CI(-1.03,1.96),P=0.54]比较,差异均无统计学意义。结论:坦索罗辛对SRSs有较好的治疗作用,联合抗胆碱能药物能获得更好的治疗效果。
