Loading...

Table of Content

    20 March 2017 Volume 36 Issue 3
      
    The law of particle dynamics summarized by several simple models
    BAO Jing-dong,PENG Jing
    College Physics. 2017, 36(3):  1-4.  doi:10.16854 /j.cnki.1000-0712.2017.03.001
    Abstract ( 1273 )   PDF (473KB) ( 999 )  
    Related Articles | Metrics
    Illumined by 2016’s Nobel prize and Feynman s physical education,we discuss deficient for the moment of college physics,i.e., searching origin and generalization of result.Several key points are summarized from the Atwood machine, trajectory of throwing body,non-inertial system on the tilted surface,a coed on a stable as examples.Namely,the relation between a few variables through derivation of the restrict equation is found; idealization and dimensionless of the trajectory curve; effective gravity force in the non-inertial system; the motion tendency of a system is judged by using the reversal thinking.
    Landau spectrum of monolayer MoS2 in a nonuniform magnetic field
    HUANG Ze-yuan,SHEN Ai-ying,WANG Da-li
    College Physics. 2017, 36(3):  5-7.  doi:10.16854 /j.cnki.1000-0712.2017.03.002
    Abstract ( 1622 )   PDF (431KB) ( 883 )  
    Related Articles | Metrics
    Monolayer MoS2 is a new kind of graphene - like materials,which exhibits many novel physical properties different from monolayer graphene due to the greater spin - orbit coupling. Based on the elementary concepts of quantum mechanics,the exotic Landau level structure in monolayer MoS2ubjected to a non -uniform   magnetic field is investigated by means of special function theory.
    A research for two-dimensional standing waves on sectorial plate
    FANG Yi-zhong,SHEN Han,CUI Xin-tu,LIAO De-ju,FENG Rao-hui,WANG Gang
    College Physics. 2017, 36(3):  8-13.  doi:10.16854 /j.cnki.1000-0712.2017.03.003
    Abstract ( 1344 )   PDF (1123KB) ( 911 )  
    Related Articles | Metrics
    Using the variables - separated method under the polar coordinate system,the normal modes of analytical solution of small flexivity vibration equation on a sectorial thin plate along the vertical direction is studied experimentally and theoretically when the boundary is free.The radii of arc-shaped standing wave nodes on the thin plate are calculated exactly for different frequencies,the laws of equation’s eigen-values and the modulus of plate are obtained.The figures of standing waves are also plotted.Two kinds of standing wave nodes are observed on the board: only radical nodes and both of arc - shaped and radical shape nodes. The theoretical results are in well agreement with the experimental measurements.
    Deducing adiabatic equation of ideal gas via kinetic theory of gas
    HOU Ji-xuan1,SI Li-ming2,WENG Hua3
    College Physics. 2017, 36(3):  14-15.  doi:10.16854 /j.cnki.1000-0712.2017.03.004
    Abstract ( 1578 )   PDF (149KB) ( 765 )  
    Related Articles | Metrics
    By using statistical physics,we obtain the adiabatic equation of an ideal gas contained in a heat-insulated cylinder with a slow-moving piston.
    The experiment of measurement the air drag coefficient   of different shape objects
    LIU Yang-zheng,QIAN Yang-de
    College Physics. 2017, 36(3):  16-19.  doi:10.16854 /j.cnki.1000-0712.2017.03.005
    Abstract ( 3713 )   PDF (961KB) ( 4725 )  
    Related Articles | Metrics
    In order to measure the air drag coefficients for the circular plate, the cylinder and the streamline   body,a small wind tunnel of adjustable air velocity is designed. The height difference of U type tube in the water column is used to express the air velocity with method of orifice plate through a cantilever beam force sensor measurement air drag of test item. The air drag coefficient is determined according to the air resistance and the difference of the height of the water in U tube.
    Formula of equivalent resistance between any two nodes of n step network
    ZHOU Qian,TAN Zhi-zhong
    College Physics. 2017, 36(3):  20-24.  doi:10.16854 /j.cnki.1000-0712.2017.03.006
    Abstract ( 1517 )   PDF (406KB) ( 1467 )  
    References | Related Articles | Metrics
    Considering the equivalent resistance between any two nodes of n step resistor network,which is a difficult problem that has not been solved before.First of all,we present a general formula of equivalent resistance between any two nodes of n step resistor network. Second,we model the differential equation by the method of network analysis,and model the constraint equation by the currents of input and output,thus the formula of equivalent resistance is proved by using the above equations.Finally,the formula of equivalent resistance of infinite network is given,and the conclusions in special cases are compared and discussed with other conclusions,and thus the correctness of the conclusions obtained is validated.
    The changing mass cooling method for measuring the specific heat of oil
    LIU Su-mei,MA Hong-zhang,YIN Yu-fang,LIU Bing,ZHAN Kai-yun,LI Shu-guang
    College Physics. 2017, 36(3):  25-27.  doi:10.16854 /j.cnki.1000-0712.2017.03.007
    Abstract ( 1448 )   PDF (384KB) ( 1396 )  
    Related Articles | Metrics
    The electric heating method is a common method used in the liquid specific heat capacity measurement experiment,a part of the experiment error comes from the changing heating power that leads to difficulty in accurately calculating total quantity of the heat. Based on the Newton's law of cooling,the relationship between the heat capacity of the system and the cooling speed of the system is derived under the condition of different quality of the oil test samples and the measuring scheme for oil specific heat capacity is designed. The experimental result shows that the measuring relative error of the method proposed in the paper can be less than 0.03. The advantages of this method are the operability,simple data processing and anti-interference of unstable heating power.
    Measurement of distance of virtual light sources using object equaling image method in Fresnel biprism interference
    LIU Qiu-wu,WANG Xiao-huai
    College Physics. 2017, 36(3):  28-31.  doi:10.16854 /j.cnki.1000-0712.2017.03.008
    Abstract ( 1910 )   PDF (485KB) ( 1882 )  
    Related Articles | Metrics
    In this paper,we analyze the relative error of the distance between two virtual light sources by secondary imaging method in Fresnel biprism interference,derive that the measurement error of the smaller image is a major factor,and put forward a more accurate method by measuring image size when the slit is located 2f in front of the lens to measure the distance of two virtual light sources and the inference distance between the virtual light sources and the micrometer eyepiece reticle.
    Experimental study of influence of light strength on the characteristics of olar battery
    WANG Yu-qing,REN Xin-cheng
    College Physics. 2017, 36(3):  32-35.  doi:10.16854 /j.cnki.1000 -0712.2017.03.009
    Abstract ( 2649 )   PDF (773KB) ( 4453 )  
    Related Articles | Metrics
    The correlation theory of characteristics of solar battery is represented,the relationships between open-circuit voltage,short -circuit current,optimum output power,optimum load resistance,packing factor of solar battery and light strength are studied by the experimental method. The results show that the open-circuit voltage, short-circuit current and maximum output power increase with the increase of light intensity,and optimum load resistance,packing factor decrease with increasing light intensity. It is shown that with weakening the light strength and increasing the optimum load resistance,which did not report for relevant theoretical analysis or simulation results. The other results are consistent with the correlation theory of characteristics of solar battery.
    Research on the teaching reform of college physics experiment under the cultivation of creative talents
    ZHANG Feng-qin,LIN Xiao-long,WANG Xiao
    College Physics. 2017, 36(3):  36-39.  doi:10.16854/j.cnki.1000-0712.2017.03.010
    Abstract ( 1450 )   PDF (170KB) ( 1419 )  
    Related Articles | Metrics
    Starting from two main sides of teachers and students,we improve the quality of teachers and the teaching condition of experiment. In order to train more outstanding creative talents,we also take the teaching reforms of college physics experiment in many ways, such as adopting a new hierarchical teaching system,an open university physics demonstration experiment,an experiment preview system,the practice teaching platform in and out college physics experiment course.
    Research on interferometry measuring Young's modulus of rubber materials
    CAO Xu,WANG Jie,QI Kai,HAN Li-li
    College Physics. 2017, 36(3):  40-43.  doi:10.16854 /j.cnki.1000-0712.2017.03.011
    Abstract ( 1803 )   PDF (280KB) ( 1787 )  
    Related Articles | Metrics
    The common measurement method of rubber tensile Young' s modulus is the optical lever one. By means of splitting pointed intervention,small diameter variation of the rubber rod under action of an external force is measured. The material of the Poisson's ratio,diameter variation and the function relation between Young's modulus reduce the random error through the experiment many times measurement data. The best estimate of the uncertainty for   calculating the Young' s modulus is analyzed. The experimental results show that theoretical error of the present method is around 1.5%,the maximum relative uncertainty is about 1.2%.
    Development of magnetic balance beam type liquid interface tensiometer
    WANG Jie,CHEN Zhi-yan,CAO Xu,WANG Jun
    College Physics. 2017, 36(3):  44-46.  doi:10.16854 /j.cnki.1000-0712.2017.03.012
    Abstract ( 1123 )   PDF (437KB) ( 570 )  
    Related Articles | Metrics
    Liquid interfacial tension coefficient is one of the important physical parameters and realizing the precise measurement of the interfacial tension coefficient of liquid has important application value. We design a new set of liquid interface tensiometer on the basis of the original instrument. The instruments of this kind with optimized suspension girder structure realizes effective amplification of the surface tension,and the introduction of magnetic levitation technology and Hall element displacement detection system can realize accurate measurement of liquid surface tension method. The designed apparatus has simple structure,measurement precision and repeatability.
    Experimental study on the phase locking of magnetic pendulum
    XU Ming-hui,BAI Zai-qiao
    College Physics. 2017, 36(3):  47-51.  doi:10.16854 /j.cnki.1000-0712.2017.03.013
    Abstract ( 1512 )   PDF (1964KB) ( 533 )  
    Related Articles | Metrics
    In certain conditions,magnetic pendulum periodically driven by a coil can become phase-locked with the driving signal and lead to stable oscillation. We study the transient process of the phase locking and measure the amplitude and phase of the pendulum in various controlling conditions. Based on the nonlinearity of   pendulum and the phase-dependent energy transfer between the pendulum and driving coil,a negative feedback mechanism is identified in the system,from which all the experimental results can be explained quantitatively.
    Measurement and research on dynamic characteristic of Hall element
    WANG Xin-yan,YAN Zheng,JIANG Shu-qi,WANG Ke,NING Lu
    College Physics. 2017, 36(3):  52-56.  doi:10.16854 /j.cnki.1000-0712.2017.03.014
    Abstract ( 1579 )   PDF (778KB) ( 1419 )  
    References | Related Articles | Metrics
    An experimental method is employed to study the dynamic characteristics of the Hall element in alternating current and the alternating magnetic field. The experiment is based on Hall effect,changed an argument and passed through an alternating signal with keeping other conditions unchanged,observed experimental results, obtained amplitude frequency and phase frequency characteristics of the Hall voltage. From the results of the experiment,we find that there is a large difference between the dynamic and static characteristics of the Hall element.
    Measuring the density of coating film using β rays
    ZHU Peng-rui,WEN Jie,YAO Yu-hua,LIU Li-jun,KANG Ming-ming,ZHANG Zhi-you
    College Physics. 2017, 36(3):  57-62.  doi:10.16854 /j.cnki.1000-0712.2017.03.015
    Abstract ( 1346 )   PDF (445KB) ( 1099 )  
    Related Articles | Metrics
    We measure the density of an aluminum coating film with the relativistic effect experimental spectrometer based on β-ray attenuation and electron energy losses in materials. The systematic error in energy loss method is large due to the widely distributed electron energy spectrum leaving lots of room for improvement. The density of aluminum coating film sample measured in β-ray attenuation method is ( 2.6 ± 0.2) g /cm2 .
    Analysis and check of cellphone's electromagnetic radiation of undergraduates
    PAN Yue-yue,WU Guang-fen,LI Xu,LI Wang
    College Physics. 2017, 36(3):  63-65.  doi:10.16854 /j.cnki.1000-0712.2017.03.016
    Abstract ( 1329 )   PDF (760KB) ( 1041 )  
    References | Related Articles | Metrics
    The ME3030B electromagnetic radiation analyzer and the HF32D electromagnetic radiation analyzer are used to determine the electromagnetic radiation' s data of cellphone when it is put in different conditions. A mountain of statistics have indicated that although the electric field intensity is different when the cellphones are put in different environment or conditions,the radiation levels electromagnetic radiation' s protection,however,the maximal moment electric field intensity is far beyond the reference value GB870288 when the cellphones are in different uses. Also,the electric field intensity reduces very quickly with increasing distance between the analyzer and  the cellphone.
     
    College Physics. 2017, 36(3):  66. 
    Abstract ( 607 )   PDF (171KB) ( 247 )  
    References | Related Articles | Metrics