Hot plate forming using a cell-typed die is a process for forming a large thick plate with a spherical shape for the manufacture of a large spherical LNG tank.Cell-typed upper and lower dies made of a framework of ste...Hot plate forming using a cell-typed die is a process for forming a large thick plate with a spherical shape for the manufacture of a large spherical LNG tank.Cell-typed upper and lower dies made of a framework of steel plates fitted to make a grid pattern are used in this process,and an air-cooling device is separately installed inside the lower die.A finite element analysis (FEA) technique was developed,which included hot forming,air flow,cooling and thermal deformation analysis for the hot plate forming process using the cell-typed die.Further,the convective and interface heat transfer coefficients were used to reproduce analytically the effects of the cooling device in the hot plate forming analysis.A small-scale model test of the process was conducted to verify the FEA technique.The analysis results show that the curvature of the final plate agrees well with that of the designed experiment within a maximum relative error of 0.03% at the corner of the plate.展开更多
目的:分析应用掌侧接骨板方法治疗桡骨远端die-punch骨折的临床可行性。方法:选取我院2014年12月~2015年12月已接受掌侧接骨板治疗的远端die-punch骨折患者32例为对象。32例患者的die-punch骨折类型主要有三种,为纵向劈裂类型、掌侧类...目的:分析应用掌侧接骨板方法治疗桡骨远端die-punch骨折的临床可行性。方法:选取我院2014年12月~2015年12月已接受掌侧接骨板治疗的远端die-punch骨折患者32例为对象。32例患者的die-punch骨折类型主要有三种,为纵向劈裂类型、掌侧类型、背侧类型。治疗所用的接骨板的类型为万向双柱锁定加压类型及2.4 mm T类型。患者手术后选择性进行一些功能恢复训练,如术后1个月内行手掌和指关节的活动,术后超1个月行腕关节活动训练。对32例患者进行随访,相关内容有X片、DASH评分、腕部是否出现畸形、并发症情况、握力、腕关节活动情况。探究采用不同die-punch骨折类类型和不同接骨板类型患者之间上述指标的差异。结果:成功随访了32例患者,经X片发现骨折愈合状况良好,且关节面也较为平整,未出现并发症和腕部畸形现象。不同die-punch骨折类型和不同接骨板类型患者DASH评分、握力、腕关节活动状况差异均无统计学意义(P>0.05)。结论:应用掌侧接骨板方法治疗桡骨远端die-punch骨折具有临床可行性。展开更多
Electroless nickel-plating on die cast magnesium alloy AZ91D was investigated. Growth of the electroless nickel-plating coating was characterized using scanning electron microscopy. Corrosion resistance of the coating...Electroless nickel-plating on die cast magnesium alloy AZ91D was investigated. Growth of the electroless nickel-plating coating was characterized using scanning electron microscopy. Corrosion resistance of the coating was evaluated by open circuit potential and potentiodynamic polarization curves in 3.5%(mass fraction) NaCl solution. The results show that plating deposition is initiated on the crevices and then spread onto primary α phase. The corrosion potentials for die cast magnesium alloy AZ91D and nickel-plating coating are about -1.45 V and -0.36 V(vs. SCE),respectively. No discoloration,cracks,blisters,or peeling appear by heat-quench test. The results show that the corrosion potential of Ni-P coating is increased by 1 000 mV and corrosion resistance for die cast magnesium alloy AZ91D is improved. The adhesion between the coating and the substrate is excellent. Electroless nickel plating is a promising method to enhance magnesium alloys resistance for attacking.展开更多
In order to produce thick plates with complicated curved surface, a prototype bending machine by the use of high frequency inductor was developed. The bending mechanism is based on the localized stresses which are in...In order to produce thick plates with complicated curved surface, a prototype bending machine by the use of high frequency inductor was developed. The bending mechanism is based on the localized stresses which are induced from the difference of temperature in thickness by the high frequency inductor. The operating speed and the thickness of plate were examined from the experiment, and the variation of the temperature was measured. Finite element analysis was carried out in the second part based on the experimentally obtained temperature distribution. The so-called Mindlin plate element was used in order to perform the simulation efficiently. The strategy to produce such curved surface in the practical process was discussed and further perspective of the production system was described. (Edited author abstract) 6 Refs.展开更多
基金Project(2010-0008-277)supported by the NCRC(National Core Research Center)Program through the National Research Foundation of Korea,funded by the Ministry of Education,Science,and TechnologyProject supported by R&D for Technology Development Program of Ministry of Knowledge Economy,Korea
文摘Hot plate forming using a cell-typed die is a process for forming a large thick plate with a spherical shape for the manufacture of a large spherical LNG tank.Cell-typed upper and lower dies made of a framework of steel plates fitted to make a grid pattern are used in this process,and an air-cooling device is separately installed inside the lower die.A finite element analysis (FEA) technique was developed,which included hot forming,air flow,cooling and thermal deformation analysis for the hot plate forming process using the cell-typed die.Further,the convective and interface heat transfer coefficients were used to reproduce analytically the effects of the cooling device in the hot plate forming analysis.A small-scale model test of the process was conducted to verify the FEA technique.The analysis results show that the curvature of the final plate agrees well with that of the designed experiment within a maximum relative error of 0.03% at the corner of the plate.
文摘目的:分析应用掌侧接骨板方法治疗桡骨远端die-punch骨折的临床可行性。方法:选取我院2014年12月~2015年12月已接受掌侧接骨板治疗的远端die-punch骨折患者32例为对象。32例患者的die-punch骨折类型主要有三种,为纵向劈裂类型、掌侧类型、背侧类型。治疗所用的接骨板的类型为万向双柱锁定加压类型及2.4 mm T类型。患者手术后选择性进行一些功能恢复训练,如术后1个月内行手掌和指关节的活动,术后超1个月行腕关节活动训练。对32例患者进行随访,相关内容有X片、DASH评分、腕部是否出现畸形、并发症情况、握力、腕关节活动情况。探究采用不同die-punch骨折类类型和不同接骨板类型患者之间上述指标的差异。结果:成功随访了32例患者,经X片发现骨折愈合状况良好,且关节面也较为平整,未出现并发症和腕部畸形现象。不同die-punch骨折类型和不同接骨板类型患者DASH评分、握力、腕关节活动状况差异均无统计学意义(P>0.05)。结论:应用掌侧接骨板方法治疗桡骨远端die-punch骨折具有临床可行性。
文摘Electroless nickel-plating on die cast magnesium alloy AZ91D was investigated. Growth of the electroless nickel-plating coating was characterized using scanning electron microscopy. Corrosion resistance of the coating was evaluated by open circuit potential and potentiodynamic polarization curves in 3.5%(mass fraction) NaCl solution. The results show that plating deposition is initiated on the crevices and then spread onto primary α phase. The corrosion potentials for die cast magnesium alloy AZ91D and nickel-plating coating are about -1.45 V and -0.36 V(vs. SCE),respectively. No discoloration,cracks,blisters,or peeling appear by heat-quench test. The results show that the corrosion potential of Ni-P coating is increased by 1 000 mV and corrosion resistance for die cast magnesium alloy AZ91D is improved. The adhesion between the coating and the substrate is excellent. Electroless nickel plating is a promising method to enhance magnesium alloys resistance for attacking.
文摘In order to produce thick plates with complicated curved surface, a prototype bending machine by the use of high frequency inductor was developed. The bending mechanism is based on the localized stresses which are induced from the difference of temperature in thickness by the high frequency inductor. The operating speed and the thickness of plate were examined from the experiment, and the variation of the temperature was measured. Finite element analysis was carried out in the second part based on the experimentally obtained temperature distribution. The so-called Mindlin plate element was used in order to perform the simulation efficiently. The strategy to produce such curved surface in the practical process was discussed and further perspective of the production system was described. (Edited author abstract) 6 Refs.
