滤波片透过率曲线测量中棱镜单色仪参数的选取

从理论上分析了入射、出射狭缝大小对出射光的光谱宽度和透过率曲线的影响，得到了入射、出射狭缝大小的最佳匹配条件，并通过实验验证了这一结论，分析了鼓轮每次转动格数对测得的透过率曲线的影响，给出了鼓轮每次转动的最佳格数值．     

平头pH电极-流动注射联用技术快速滴定食醋中醋酸的方法研究

采用一种具有平头结构的pH电极作为流动注射分析(FIA)的检测器,构建了流动注射自动化酸度滴定系统.优化了样品进样量、流速、载液浓度和反应管长度等参数.用NaOH溶液作为载液,在4.639×10-4～0.212 mol·L-1范围内醋酸浓度的对数与FIA峰的峰面积成正比,该方法的相对标准偏差(RSD)小于0.5%.采用...     

The Blood Flow at Arterial Bifurcations Simulated by the Lattice Boltzmann Method

The Programmed model of non-Newtonian blood fiow （the Casson model） at arterial bifurcations is established by the lattice Boltzmann method. The blood flow field under different Reynolds numbers is simulated, and distri- bution of dynamic factors such as flow velocity, shear stress, pressure and shear rate are presented. The existence of the fluid separation zone is analyzed. This provides a basis for further studies of the relationship between hemodynamic factors and pathogenesis, as well as a reference for a better understanding of the pathological changes and location of sediments, and the plague factor in arteries.     

掺La锆钛酸铅压电陶瓷(PLZT)在光Kerr效应教学实验中的应用

通过实验表明高掺La的PLZT具有较高的二次电光系数,用PLZT做Kerr效应教学实验具有明显的优势。     

利用PASCO系统研究阻力情况下二自由度系统的振动

本文从理论和实验两个方面探究了二自由度系统的振动,在考虑摩擦力和空气阻力的影响后给出了运动方程.使用3个弹簧和两个位置传感器搭建了实验装置,利用PASCO系统进行了实验,并比照数值模拟结果,得出了本系统两传感器滑块所受的摩擦力分别为0.003 075 N和0.003 225 N,空气阻力系数C为1.0,并验证了所研究系统建模的准确性.本实验结果对多自由度系统的振动问题的研究有一定参考价值.     

平头pH电极用于流动注射-电位滴定法测定碱溶液的浓度

以盐酸溶液为滴定剂,采用流动注射-平头pH电极测定强碱(如氢氧化钠溶液)及弱碱(如氨水)溶液的浓度。选择流动注射分析系统的工作参数为:①混合管长度40 cm;②载流盐酸溶液浓度1.027×10-3mol·L-1;③样品进样量310μL;④流速0.82 mL·min-1。结果表明:氢氧化钠和氨水的峰面积、峰高和半峰宽均与其浓度的对数值在一定的范围内呈线性关系。方法用于实际样品分析,滴定灵敏度比手工滴定方法的灵敏度高10倍,测定值的相对标准偏差(n=5)在1.1%~1.8%之间。     

基于LabVIEW的声波谐振管实验研究

为了更高效地测量声波谐振管的谐振频率,本文基于LabVIEW设计了测量声波谐振管谐振频率的扫频程序,分别得到了两端闭管条件下不同管长的谐振频率,以及首端闭管与尾端闭管条件下的谐振频率.此外,还通过绘制管内驻波波形图对声压波腹发生偏离的假设进行了验证.最后,对谐振管管身小孔开闭对谐振频率的影响进行了探究,发现小孔位置越接近驻波的声压波腹,谐振频率的偏离量越大.     

Simulating High Reynolds Number Flow by Lattice Boltzmann Method

A two-dimensional channel flow with different Reynolds numbers is tested by using the lattice Boltzmann method under different pressure and velocity boundary conditions. The results show that the simulation error increases,and the pressure and the flow rate become unstable under a high Reynolds number. To improve the simulation precision under a high Reynolds number, the number of fluid nodes should be enlarged. For a higher Reynoldsnumber flow, the velocity boundary with an approximately parabolic velocity profile is found to be more adaptive.Blood flow in an artery with cosine shape symmetrical narrowing is then simulated under a velocity boundary condition. Its velocity, pressure and wall shear stress distributions are consistent with previous studies.     

THE COMPARISON OF GREEN FUNCTION FOR QUASI-LINEAR ELLIPTIC EQUATION

A generalization of the usual Green function to a kind of nonlinear elliptic equation of divergence form is discussed. The regularity and comparison principle of Green function in the sense of distribution are shown.     

Simulation of Blood Flow at Vessel Bifurcation by Lattice Boltzmann Method

The application of the lattice Boltzmann method to the large vessel bifurcation blood flow is investigated in a wide range of Reynolds numbers. The velocity, shear stress and pressure distributions at the bifurcation are presented in detail The flow separation zones revealed with increase of Reynolds number are located in the areas of the daughter branches distal to the outer corners of the bifurcation where some deposition of particular blood components might occur to form arteriosclerosis. The results also demonstrate that the lattice Boltzmann method is adaptive to simulating the flow in larger vessels under a high Reynolds number.