杆件力学性能分析是大学生结构设计竞赛模型优化的核心课题,采用电子压力试验机,系统地测试了108根不同厚度(0.2 mm、0.35 mm和0.5 mm)和宽度(3 mm至8 mm)的竹皮纸拉杆,以及42个样本的0.35 mm厚、6 mm宽的单层压杆、双层压杆和单层加横...杆件力学性能分析是大学生结构设计竞赛模型优化的核心课题,采用电子压力试验机,系统地测试了108根不同厚度(0.2 mm、0.35 mm和0.5 mm)和宽度(3 mm至8 mm)的竹皮纸拉杆,以及42个样本的0.35 mm厚、6 mm宽的单层压杆、双层压杆和单层加横向肋压杆的极限承载力。实验结果表明,0.35 mm厚度的竹皮纸拉杆在抗拉性能上优于0.2 mm和0.5 mm厚度的拉杆,且拉杆的宽度与抗拉强度之间存在正相关关系。因此,建议优先选择0.35 mm厚度的竹皮纸作为拉杆材料。基于实验数据,构建了一个三维模型,描述了宽度、厚度与极限抗拉强度之间的关系。对于压杆试验,加横向肋会降低压杆的极限抗压强度,但能显著提升压杆的抗弯、抗剪和局部稳定性。研究进一步分析了不同加横向肋间距对压杆性能的影响,发现当间距与杆件宽度比值为5时,杆件综合性能较好。The mechanical performance analysis of members is a central topic in the optimization of models for college students’ structural design competitions. Utilizing an electronic universal testing machine, a systematic test was conducted on 108 bamboo veneer paper tension members of varying thicknesses (0.2 mm, 0.35 mm, and 0.5 mm) and widths (ranging from 3 mm to 8 mm), as well as 42 samples of single-layer compression members, double-layer compression members, and single-layer compression members reinforced with transverse ribs, each with a thickness of 0.35 mm and a width of 6 mm, to determine their ultimate load-bearing capacity. The experimental results indicate that the bamboo veneer paper tension members with a thickness of 0.35 mm exhibit superior tensile performance compared to those with thicknesses of 0.2 mm and 0.5 mm, and there is a positive correlation between the width of the tension members and their tensile strength. Consequently, it is recommended to prioritize the selection of bamboo veneer paper with a thickness of 0.35 mm as the material for tension members. Based on the experimental data, a three- dimensional model was constructed to describe the relationship among width, thickness, and ultimate tensile strength. For the compression member tests, the addition of transverse ribs was found to reduce the ultimate compressive strength of the compression members but significantly enhance their flexural, shear, and local stability. Further analysis of the impact of different spacings of transverse ribs on the performance of compression members revealed that a spacing-to- width ratio of 5 yields optimal comprehensive performance of the members.展开更多
Porous silver-modified ZnO microrods photocatalysts were synthesized through direct thermal decomposition of the Ag-doped zinctartrate precursor,which was prepared by homogeneous precipitation method at 80 °C for...Porous silver-modified ZnO microrods photocatalysts were synthesized through direct thermal decomposition of the Ag-doped zinctartrate precursor,which was prepared by homogeneous precipitation method at 80 °C for 2 h.The obtained samples were characterized by XRD,FTIR,TG？DTA and UV-VIS absorption spectroscopy.The photocatalytic activity of the as-prepared porous Ag/ZnO microrods was tested with the photocatalytic degradation of methyl orange.The results indicate that doping Ag greatly improves the photocatalytic efficiency of ZnO and 3% Ag-doped（mole fraction） ZnO porous microrod photocatalyst exhibits the highest photocatalytic decolorization efficiency,leading to as much as 80% reduction of MO concentration in 120 min.Moreover,the 3% Ag-doped porous microrods also possess higher photocatalytic activity under the real sunlight irradiation.展开更多
The mineral of manganese oxalate dihydrate was synthesized in aqueous and organic-water binary solvent system (OWBS), respectively. The samples were characterized by XRD and SEM. The results show that OWBS can effecti...The mineral of manganese oxalate dihydrate was synthesized in aqueous and organic-water binary solvent system (OWBS), respectively. The samples were characterized by XRD and SEM. The results show that OWBS can effectively control the phase and morphology of manganese oxalate dihydrate. The distinction of thermal decompositon of monoclinic and orthogonal manganese oxalate dihydrate can be ascribed to the different linkage mode of manganese cation, oxalate anion and crystallized water in inter-molecules. The kinetic parameters of thermal decomposition were obtained by TG-DTA curves in various scan rates, and notably, porous manganese oxide was prepared from orthogonal manganese oxalate.展开更多
文摘杆件力学性能分析是大学生结构设计竞赛模型优化的核心课题,采用电子压力试验机,系统地测试了108根不同厚度(0.2 mm、0.35 mm和0.5 mm)和宽度(3 mm至8 mm)的竹皮纸拉杆,以及42个样本的0.35 mm厚、6 mm宽的单层压杆、双层压杆和单层加横向肋压杆的极限承载力。实验结果表明,0.35 mm厚度的竹皮纸拉杆在抗拉性能上优于0.2 mm和0.5 mm厚度的拉杆,且拉杆的宽度与抗拉强度之间存在正相关关系。因此,建议优先选择0.35 mm厚度的竹皮纸作为拉杆材料。基于实验数据,构建了一个三维模型,描述了宽度、厚度与极限抗拉强度之间的关系。对于压杆试验,加横向肋会降低压杆的极限抗压强度,但能显著提升压杆的抗弯、抗剪和局部稳定性。研究进一步分析了不同加横向肋间距对压杆性能的影响,发现当间距与杆件宽度比值为5时,杆件综合性能较好。The mechanical performance analysis of members is a central topic in the optimization of models for college students’ structural design competitions. Utilizing an electronic universal testing machine, a systematic test was conducted on 108 bamboo veneer paper tension members of varying thicknesses (0.2 mm, 0.35 mm, and 0.5 mm) and widths (ranging from 3 mm to 8 mm), as well as 42 samples of single-layer compression members, double-layer compression members, and single-layer compression members reinforced with transverse ribs, each with a thickness of 0.35 mm and a width of 6 mm, to determine their ultimate load-bearing capacity. The experimental results indicate that the bamboo veneer paper tension members with a thickness of 0.35 mm exhibit superior tensile performance compared to those with thicknesses of 0.2 mm and 0.5 mm, and there is a positive correlation between the width of the tension members and their tensile strength. Consequently, it is recommended to prioritize the selection of bamboo veneer paper with a thickness of 0.35 mm as the material for tension members. Based on the experimental data, a three- dimensional model was constructed to describe the relationship among width, thickness, and ultimate tensile strength. For the compression member tests, the addition of transverse ribs was found to reduce the ultimate compressive strength of the compression members but significantly enhance their flexural, shear, and local stability. Further analysis of the impact of different spacings of transverse ribs on the performance of compression members revealed that a spacing-to- width ratio of 5 yields optimal comprehensive performance of the members.
基金Project (20907001) supported by the National Natural Science Foundation of ChinaProject (KJ2010A336) supported by the University Natural Science Research Project of Anhui Province,ChinaProject (KJ2009A010Z) supported by the Educational Commission of Anhui Province,China
文摘Porous silver-modified ZnO microrods photocatalysts were synthesized through direct thermal decomposition of the Ag-doped zinctartrate precursor,which was prepared by homogeneous precipitation method at 80 °C for 2 h.The obtained samples were characterized by XRD,FTIR,TG？DTA and UV-VIS absorption spectroscopy.The photocatalytic activity of the as-prepared porous Ag/ZnO microrods was tested with the photocatalytic degradation of methyl orange.The results indicate that doping Ag greatly improves the photocatalytic efficiency of ZnO and 3% Ag-doped（mole fraction） ZnO porous microrod photocatalyst exhibits the highest photocatalytic decolorization efficiency,leading to as much as 80% reduction of MO concentration in 120 min.Moreover,the 3% Ag-doped porous microrods also possess higher photocatalytic activity under the real sunlight irradiation.
文摘The mineral of manganese oxalate dihydrate was synthesized in aqueous and organic-water binary solvent system (OWBS), respectively. The samples were characterized by XRD and SEM. The results show that OWBS can effectively control the phase and morphology of manganese oxalate dihydrate. The distinction of thermal decompositon of monoclinic and orthogonal manganese oxalate dihydrate can be ascribed to the different linkage mode of manganese cation, oxalate anion and crystallized water in inter-molecules. The kinetic parameters of thermal decomposition were obtained by TG-DTA curves in various scan rates, and notably, porous manganese oxide was prepared from orthogonal manganese oxalate.
