Hole-drilling method is a commonly used method for measuring residual stress. The calibration coefficients in ASTM E837-13 a would cause large errors due to the plasticity deformation of materials. In the study, calib...Hole-drilling method is a commonly used method for measuring residual stress. The calibration coefficients in ASTM E837-13 a would cause large errors due to the plasticity deformation of materials. In the study, calibration coefficients were modified in the plasticity deformation stage based on the distortion energy theory. The calibration experiment of calibration coefficients was simulated by the finite element model, and the plasticity modification formulas of 7075 aluminum alloy were obtained. From the results of uniaxial tensile loading test, the measuring errors of high residual stress are significantly reduced from-4.071%～53.440% to-5.140% ～ 0.609% after the plasticity modification. This work provides an effective way to expand the application of hole-drilling method.展开更多
Convenient and integration fabrication process is a key issue for the application of functional nanofibers.A surface functionalization method was developed based on coaxial electrospinning to produce ultraviolet(UV)pr...Convenient and integration fabrication process is a key issue for the application of functional nanofibers.A surface functionalization method was developed based on coaxial electrospinning to produce ultraviolet(UV)protection nanofibers.The titanium dioxide(TiO_(2))nanoparticles suspension was delivered through the shell channel of the coaxial spinneret,by which the aggregation of TiO_(2) nanoparticles was overcome and the distribution uniformity on the surface of polyethylene oxide(PEO)nanofiber was obtained.With the content of TiO_(2) increasing from 0 to 3%(mass fraction),the average diameter of nanofibers increased from(380±30)nm to(480±100)nm.The surface functionalization can be realized during the electrospinning process to gain PEO/TiO_(2) composite nanofibers directly.The uniform distribution of TiO_(2) nanoparticles on the surface of nanofibers enhanced the UV absorption and resistance performance.The maximum UV protection factor(UPF)value of composite nanofibers reaches 2751.This work presented a novel surface-functionalized way for the preparation of composite nanofiber,which has great application potential in the field of micro/nano system integration fabrication.展开更多
文摘目的:研究稳定型冠心病合并H型高血压患者血管内超声虚拟组织学冠脉斑块特征。方法 52例稳定型冠心病且合并高血压患者,依据血浆同型半胱氨酸(Hcy)水平分为合并H型高血压组、合并非H型高血压组。所有患者行冠脉造影检查确诊,计算3支血管病变比例及Gensini评分;对冠脉靶病变进行血管内超声检查及虚拟组织学分析,研究两组血管重构及斑块病变特征。结果与合并非H型高血压组比较,合并H型高血压组冠脉3支血管病变比例增高(57.14%vs 41.67%)、Gensini评分增高(30.82±7.18 vs 26.35±4.27),差异有统计学意义(P<0.05);合并H型高血压组血管重构指数、正性重构比例、斑块脂质坏死组织面积、纤维脂质组织面积较合并非H型高血压组升高(P<0.05),斑块钙化组织面积、纤维组织面积两组比较差异无统计学意义(P>0.05)。相关分析显示血浆Hcy水平与3支血管病变比例、Gensini评分、血管重构指数、正性重构比例、脂质坏死组织面积、纤维脂质组织面积存在正相关关系。结论稳定型冠心病合并H型高血压患者,其高血浆Hcy水平不但影响冠脉病变的范围和严重程度,还可能进一步加重血管重塑及斑块组分的差异,造成斑块不稳定趋势。
基金国家重点研发计划(2018YFD0500600)国家肉鸡产业技术体系项目(CARS-41-G10)+5 种基金国家自然科学基金青年基金(31802104)广东省自然科学基金(2017A030310096)国家“十二五”科技支撑计划项目子课题(2014BAD13B02)广东省科技计划项目(2017B020202003)广州市科技计划重点项目(201804020091)广东省农业科学院院长基金项目(201620,201805,201807B,201809B and 201908)
基金supported by the Natural Science Foundation of Fujian Provinceof China(No.2018J01082)the China Scholarship Council(No.201806315006)the National Natural Science Foundation of China(No.51305371)
文摘Hole-drilling method is a commonly used method for measuring residual stress. The calibration coefficients in ASTM E837-13 a would cause large errors due to the plasticity deformation of materials. In the study, calibration coefficients were modified in the plasticity deformation stage based on the distortion energy theory. The calibration experiment of calibration coefficients was simulated by the finite element model, and the plasticity modification formulas of 7075 aluminum alloy were obtained. From the results of uniaxial tensile loading test, the measuring errors of high residual stress are significantly reduced from-4.071%～53.440% to-5.140% ～ 0.609% after the plasticity modification. This work provides an effective way to expand the application of hole-drilling method.
基金This work was supported by the National Natural Science Foundation of China(No.61772441)the Science and Technology Planning Project of Fujian Province,China(No.2020H6003)+2 种基金the Xiamen Municipal Science and Technology Project,China(No.3502Z20193015)the Fund of the Aviation Key Laboratory of Science and Technology on Inertia,China(No.20180868001)the Fund of Fujian Innovation Center of Additive Manufacturing,China(No.ZCZZ202-31).
文摘Convenient and integration fabrication process is a key issue for the application of functional nanofibers.A surface functionalization method was developed based on coaxial electrospinning to produce ultraviolet(UV)protection nanofibers.The titanium dioxide(TiO_(2))nanoparticles suspension was delivered through the shell channel of the coaxial spinneret,by which the aggregation of TiO_(2) nanoparticles was overcome and the distribution uniformity on the surface of polyethylene oxide(PEO)nanofiber was obtained.With the content of TiO_(2) increasing from 0 to 3%(mass fraction),the average diameter of nanofibers increased from(380±30)nm to(480±100)nm.The surface functionalization can be realized during the electrospinning process to gain PEO/TiO_(2) composite nanofibers directly.The uniform distribution of TiO_(2) nanoparticles on the surface of nanofibers enhanced the UV absorption and resistance performance.The maximum UV protection factor(UPF)value of composite nanofibers reaches 2751.This work presented a novel surface-functionalized way for the preparation of composite nanofiber,which has great application potential in the field of micro/nano system integration fabrication.
