光杠杆镜面和望远镜光轴初始不垂直度对放大率的影响

结合光杠杆测量微小伸长量的光学原理,详细分析了静态拉伸法测量金属丝杨氏弹性模量的实验中,光杠杆镜面初始不竖直对光杠杆放大率造成的影响.分析结果表明,随着光杠杆镜面初始时与竖直方向夹角的增大,其放大率与传统教材中的放大率公式相比,将非线性地增加,进而对金属丝杨氏弹性模量的测量精度造成影响.最后给出了降低此影响的实验仪器调节步骤建议.如采用新增加的仪器调节建议,可将金属丝杨氏弹性模量测量精度的影响降低到1‰以内.     

弹性模量千分表测量方法的建立

为建立一种借助千分表测量杨氏弹性模量高精度的方法,本研究通过千分表精准测量样品受力后其微小长度变化量,进而测得其杨氏弹性模量。对所测的数据经计算分析,结果表明该方法精度高,测量结果可靠。与光杠杆法测量样品微小长度这一传统方法相比,仪器构造简单,实验现象直观,操作简便。     

基于Matlab GUI的拉伸法测杨氏弹性模量实验的数据处理

借助Matlab软件分别采用逐差法和最小二乘法对拉伸法测量杨氏弹性模量实验进行数据处理，利用Matlab GUI设计数据处理交互式界面，通过在GUI界面输入测量数据和实验参数，绘制出了拟合直线图，实现了杨氏模量值及其不确定度的程序计算，分析了两种方法求得的实验结果。数据处理过程操作简单，提高了学生运用软件的能力和实验效率。     

利用箔式应变片测量金属丝杨氏模量

杨氏弹性模量测量实验是各高校必开的经典物理实验之一.现阶段各高校实验中大都采用镜尺组测量杨氏模量,提出用箔式应变片测量杨氏弹性模量,该方法将电学和力学知识结合在一起,增强学生综合实验能力,提高创新意识.在测量时先采用精密位移平台定标,然后测量加力后惠斯通电桥输出电压值.测量数据和数据处理结果表明方法稳定性好、精度高,适合运用到实际教学中.     

用读数显微镜测金属丝的杨氏弹性模量

研究了杨氏弹性模量的测量 ,提出用读数显微镜测量的原理和方法 ,并对误差作了分析     

用单镜装置测金属棒的杨氏弹性模量

介绍了用单镜装置测金属棒的杨氏弹性模量的原理及方法 ,并对测量结果进行误差分析     

利用电容器测量杨氏弹性模量

提出用可变电容器测金属杨氏弹性模量的新方法，并从实验上测定了碳钢丝的杨氏弹性模量。     

用钟表式百分表测金属丝的杨氏弹性模量

简要介绍了用钟表式百分表测钢丝杨氏弹性模量的原理及方法, 并对测量的误差作了分析．     

复射式光杠杆

本文给出了一种新式光杠杆——复射式光杠杆的结构，并用新旧两种光杠杆测定杨氏弹性模量进行了对比实验，给出了测量结果及误差。     

金属丝在静态拉伸时滞后现象的观测

在用静态拉伸法测量金属丝杨氏弹性模量实验中,可以明显观察到弹性滞后现象。本文通过测量数据和弹性特性曲线直观展示了金属丝在静态拉伸时的弹性滞后现象,估算了滞后的大小。     

游标卡尺在测定金属杨氏模量中的应用

根据拉伸法测量金属杨氏模量的原理,利用现有的杨氏模量仪,设计了一套应用游标卡尺测定金属杨氏模量的方法。     

动态法测杨氏模量实验的探索与改进

本文的主要工作有:分析了国内外杨氏模量测量的原理与方法;把测量装置由悬挂法改为支撑法,增加了实验棒的长度(原实验棒长度16 cm,新实验棒长度23 cm),扩大了数据的测量范围;移动支架置于导轨上,可直接在导轨标尺上准确读数,每隔3 mm测一次数据,数据增多;组装调试实验装置,测量了黄铜、纯铜、钛三种材料的杨氏模量并进行数据处理,将改进后实验系统测得的结果和原实验系统测得的结果以公认值进行比较,完善了改进后实验系统的教学功能。     

对液压法测杨氏模量的实验研究

引入了液压法测量杨氏模量,用液压微位移放大原理来表征微小变化量,用液压微位移放大器对传统的实验装置进行改进,通过实验原理、误差分析,结合测量结果,对此实验方法进行分析与讨论,由此给出了一种测量杨氏模量新的方法.     

弯曲共振法测量材料的杨氏模量实验改进

针对共振法测量杨氏模量实验中存在精确度和获取共振频率上的不足,在原装置中增加高度调节装置和水平仪,通过实验操作对共振阶数进行判断.实验结果证明选用共振二阶型态测量杨氏模量较有优势.     

杨氏模量测定实验的整体改进

拉伸法测定金属丝杨氏弹性模量实验是力学的一个基础性实验.本文提出一种创新方法并研制了新的仪器,用微型激光器代替原来的尺读望远镜,大幅提高了测量精度,明显改善了实验操作性.实践证明,该仪器具备良好教学效果.     

Nanoindentation study of Cu52Zr37Ti8In3 bulk metallic glass

In this paper, Cu₅₂Zr₃₇Ti₈In₃ bulk metallic glass has been studied by nanoindentation. Three different ways for nanoindentation tests were employed. Load-control nanoindentation was used to investigate the effect of the loading rate on the hardness and Young’s modulus. Young’s modulus of the specimen shows a loading rate dependence. The constant-load indentation creep measurement was performed. The creep data were fitted with the generalized Kelvin model, and the compliance spectrum and retardation spectrum were derived. Furthermore, the storage compliance and loss compliance were also discussed. For characterizing the change of the hardness and Young’s modulus with increasing indentation depth, depth-control nanoindentation analysis was conducted. The results show that both the hardness and Young’s modulus decrease with nanoindentation depth.     

Nontrivial tensile behavior of rutile TiO<Subscript>2</Subscript> nanowires: a molecular dynamics study

In this paper, we study the tensile behavior of cylindrical rutile TiO₂ nanowires, employing molecular dynamics (MD) simulation technique. The third-generation charge optimized many-body (COMB3) has been used for interatomic potential modeling. The influence of temperature and nanowire diameter on Young’s modulus is investigated. Our simulations exhibit the anisotropic behavior of Young’s modulus as a function of diameter for different crystallographic orientations. Although our results are in good accord with the existing results in [1 0 0] direction, Young’s modulus adds up monotonically with increasing the cross-sectional diameter of nanowire in [0 0 1] direction. It is found that Young’s modulus of the nanowires are lower (higher) than the bulk value for [0 0 1] ([1 0 0]) direction. Furthermore, simulation results also indicate that Young’s modulus of rutile TiO₂ nanowire increases as a function of temperature for a given diameter, unexpectedly. The obtained results may be useful in the field of nanotechnology for optimizing mechanical performance to gain specific applications.     

Material property estimates from ultrasound attenuation in fibre suspensions

An investigation of a new method for measuring fibre material properties from ultrasonic attenuation in a dilute suspension of synthetic fibres of uniform geometry is presented. The method is based on inversely solving an ultrasound scattering and absorption model of suspended fibres in water for the material properties of the fibres. Experimental results were obtained from three suspensions of nylon 66 fibres each with different fibre diameters. A forward solution to the model with reference material values is compared to experimental data to verify the model’s behaviour. Estimates of the shear and Young’s modulus, the compressional wave velocity, Poisson’s ratio and loss tangent from nylon 66 fibres are compared to data available from other sources. Experimental data confirms that the model successfully predicts that the resonance features in the frequency response of the attenuation are a function of diameter. Consistent estimated values for the compressional wave velocity and the Poisson’s ratio were found to be difficult to obtain but in combination gave values of shear modulus within previously reported values and with low sensitivity to noise. Young’s modulus was underestimated by 54% but was consistent and had low sensitivity to noise. The underestimation is believed to be caused by the assumption of isotropic material used in the model. Additional tests on isotropic fibre would confirm this. Further analysis of the model sensitivity and the reasons for the resonance features are required.     

逐差法和Origin7.0软件在大学物理实验数据处理中的比较

用逐差法和Origin7.0软件分别对拉伸法测金属丝杨氏模量的实验数据进行处理,结果表明,利用Origin7.0软件处理实验数据,具有简洁、快捷与直观等特点,避免了人为因素所造成的误差,在物理实验数据处理过程中有显著的应用价值。     

Surface topography,nano-mechanics and secondary structure of wheat gluten pretreated by alternate dual-frequency ultrasound and the correlation to enzymolysis

The effects of alternate dual-frequency ultrasound (ADFU) pretreatment on the degree of hydrolysis (DH) of wheat gluten (WG) and angiotensin I-converting enzyme (ACE) inhibitory activity were investigated in this research. The surface topography, nano-mechanics and secondary structure of WG were also determined using atomic force microscope (AFM) and circular dichroism (CD). The correlations of ACE inhibitory activity and DH with surface topography, nano-mechanics and secondary structure of WG were determined using Pearson’s correlation analysis. The results showed that with an increase in either pretreatment duration or power, the ACE inhibitory activity of the hydrolysate also increases, reaching maximum at 10 min and 150 W/L, respectively, and then decreases thereafter. Similarly, AFM analysis showed that as the pretreatment duration or power increases, the surface roughness also increase and again a decrease occurs thereafter. As the pretreatment duration or power increased, the Young’s modulus and adhesion of WG also increased and then declined. Young’s modulus and adhesions average values were compared with ACE inhibitory activity reversely. The result of the CD spectra analysis exhibited losses in the relative percentage of α-helix of WG. Pearson’s correlation analysis showed that the average values of Young’s modulus and the relative percentage of α-helix correlated with ACE inhibitory activity of the hydrolysates linearly and significantly (P < 0.05); the relative percentage of β-sheet correlated linearly with DH of WG significantly (P < 0.05). In conclusion, ADFU pretreatment is an efficient method in proteolysis due to its physical and chemical effect on the Young’s modulus, α-helix and β-sheet of WG.