气质联用检测食品包装材料中的PAEs的教学实验探索

设计了一个综合性教学实验,采用超声萃取、化学浸出等前处理方法,并应用气相色谱质谱联用仪,对学生取样的六种有代表性的食品包装材料中的PAEs迁移值进行了检测。通过分析总离子流图中的丰度值和目标化合物的质谱图,确定了各包装材料中所含PAEs的种类和含量。本实验成功应用于学生的教学实验中,效果良好。     

The relaxed inexact projection methods for the split feasibility problem

In this paper we present several relaxed inexact projection methods for the split feasibility problem (SFP). Each iteration of the first proposed algorithm consists of a projection onto a halfspace containing the given closed convex set. The algorithm can be implemented easily and its global convergence to the solution can be established under suitable conditions. Moreover,we present some modifications of the relaxed inexact projection method with constant stepsize by adopting Armijo-like search. We furthermore present a variable-step relaxed inexact projection method which does not require the computation of the matrix inverses and the largest eigenvalue of the matrix A^TA, and the objective function can decrease sufficiently at each iteration. We show convergence of these modified algorithms under mild conditions. Finally, we perform some numerical experiments, which show the behavior of the algorithms proposed.     

基于FAHP的研究创新型实验项目选择

将模糊层次分析法(FAHP)应用于项目的选择中来,根据相关因素对项目的重要程度进行排序,改变了靠决策者主观选择项目这一现状,使项目的决择更科学.     

Otto Stern (1888–1969): The founding father of experimental atomic physics

We review the work and life of Otto Stern who developed the molecular beam technique and with its aid laid the foundations of experimental atomic physics. Among the key results of his research are: the experimental test of the Maxwell‐Boltzmann distribution of molecular velocities (1920), experimental demonstration of space quantization of angular momentum (1922), diffraction of matter waves comprised of atoms and molecules by crystals (1931) and the determination of the magnetic dipole moments of the proton and deuteron (1933).     

半导体阻温曲线拟合方法的研究

针对物理实验中半导体热敏电阻在一定温度范围内电阻随温度变化的关系,采用了多种方法进行曲线拟合,结果发现e指数拟合后的残差平方和最小,其次是二次三项式拟合。结果表明,对于一定范围内热敏电阻阻值随温度变化进行数据拟合以及残差分析,有利于物理实验教学向着数字化、信息化研究型方向发展。     

自制表面张力演示仪和稳定度判定仪

介绍了第3届大学生物理教学技能大赛中韩山师范学院参赛的利用身边材料自制的表面张力演示仪和稳定度判定仪.表面张力演示仪是用饮料瓶和钢丝网制成的,当瓶子倾斜时,水将流出,但若瓶子倒立时,由于水的表面张力,水反而不会流出.而稳定度判定仪是利用螺纹铁棒和木框组合而成,在稳定度判定仪的重心位置安装了一盏小灯,利用小灯在支撑面上灯光的投影来判断装置是否稳定.     

氢气和氧气生成气态水反应热力学函数的高水平量化计算研究——介绍一个计算化学实验

On the basis of teaching practice, we introduce a computational chemistry experiment for highgrade undergraduate students. This experiment uses Gaussian 09, GaussView and UltraEdit softwares to calculate the changes of thermodynamic parameters for generation of vaporous water from hydrogen and oxygen, including the internal energy, enthalpy, entropy and Gibbs free energy. Through this experiment, students will learn how to perform the geometry optimization, frequency calculation and energy calculation with the high-level quantum chemistry calculation methods.     

Accuracy of the random-incidence scattering coefficient measurement

The experimental results presented in this study aim at providing an useful insight into the accuracy of the measurement procedure of the random-incidence scattering coefficient as defined in ISO 17497-1:2004. A systematic experimental investigation has been conducted in a full-scale reverberation room. The tested diffusers are characterized by different geometrical distributions of hollow wooden cubes with an edge length of 20 cm, and different configurations of the measurement set-up. The accuracy of the measurement results has been evaluated considering the contribution of the different undefined aspects of the ISO method such as the microphones height, the air gap underneath the turntable, the sample shape, and the correction of the effects of the absorption and scattering coefficients of the base plate. The results showed that the accuracy of the measurement increases when a more rigid turntable and a circular sample are used, and when the air gap below the turntable is covered. Furthermore, the distance of the microphones from the sample surface was found to affect significantly the results, thus to influence the accuracy of the measurements.     

大学物理实验在线教学及资源建设的思考

从大学物理实验教学在军队院校人才培养中的作用入手,深入分析了传统大学物理实验教学中存在的问题与根源,结合当前该校在线教学开展的成果,阐述了开展实验在线教学的必要性。最后,针对在线教学工作的关键:在线资源建设,根据实验课程的特点,给出了从实验人文史料、课程学习须知、基本实验方法、常见仪器使用、数据处理五个方面进行资源建设的设想。     

Miller–Urey Spark-Discharge Experiments in the Deuterium World

We designed and conducted a series of primordial-soup Miller-Urey style experiments with deuterated gases and reagents to compare the spark-discharge products of a “deuterated world” with the standard reaction in the “hydrogenated world”. While the deuteration of the system has little effect on the distribution of amino acid products, significant differences are seen in other regions of the product-space. Not only do we observe about 120 new species, we also see significant differences in their distribution if the two hydrogen isotope worlds are compared. Several isotopologue matches can be identified in both, but a large proportion of products have no equivalent in the corresponding isotope world with ca. 43 new species in the D world and ca. 39 new species in the H world. This shows that isotopic exchange (the addition of only one neutron) may lead to significant additional complexity in chemical space under otherwise identical reaction conditions.