College Physics

Notes on the principles of quantum mechanics

YANG Shi-jie

College Physics. 2021, 40(11): 1. doi:10.16854 / j.cnki.1000-0712.210122

Abstract ( 909 )

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The principles of quantum mechanics as well as basic concepts and classical

correspondence are re- examined from advanced point of views. We also discusse the relation

between Planck constant and representation transformation.

Electrostatic induction of the infinite ungrounded conductor plate

FU Quan-hong, ZHENG Jian-bang, FAN Yuan-cheng, ZHANG Fu-li

College Physics. 2021, 40(11): 5. doi:10.16854 / j.cnki.1000-0712.210041

Abstract ( 1050 )

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Utilizing the uniqueness theorem of the boundary value problem of electrostatic field，we

strictly an- alyze the problem of electrostatic induction of the infinite ungrounded conductor

plate，and use the simulation soft- ware of COMSOL Multiphysics to verify the theoretically

calculated results.

Refraction relation of the extraordinary light in uniaxial crystals and its applications

XING Rong, ZHU Xiang-ping, HAN Xin

College Physics. 2021, 40(11): 9. doi:10.16854 / j.cnki.1000-0712.210150

Abstract ( 754 )

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The refraction relation of the extraordinary light ray with the incident light on

uniaxial crystals from isotropic media is derived by using Huyghens principle. And the matched

sign convention is also given. The refrac- tion relation is appropriate for the situations where

the optical axis is in the incidence plane. Three special cases are discussed with the refraction

relation. The results are as follows: when the incident light ray rotates around the inci- dence

point in the incident plane，the extraordinary light ray must rotate in the same direction; under

the particular conditions，the extraordinary light ray can appear at the side of the

interfacial normal where the incident light ray exists; the refraction angle of the

extraordinary light ray has a maximum value when the incident angle is 90°.

Geometric phase of one-dimensional forced harmonic oscillator

SUN Yu-ming

College Physics. 2021, 40(11): 12. doi:10.16854 / j.cnki.1000-0712.210231

Abstract ( 764 )

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Combining the unitary transformation method and Lie algebra method，a simple method

for solving one-dimensional forced harmonic oscillator is given，and the geometric phases of

cyclic and non-cyclic evolution of quantum states are discussed.

vibration law of Wilberforce pendulum

JIANG Fu-jin¹, HAN Can²

College Physics. 2021, 40(11): 15. doi:10.16854 / j.cnki.1000-0712.210083

Abstract ( 2338 )

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In this paper，a possible vibration model is conjectured according to the vibration

characteristics of Wilberforce pendulum. Based on this model，the dynamic differential equations of

Wilberforce pendulum are written out. Then the normal frequency and the analytical solution of the

vibration are obtained. Finally，the numerical sim- ulation of the analytical solution is carried

out and compared with the experimental data，which proves the rationali- ty of the conjecture

Development of a comprehensive experimental instrument for magnetic field and Ampere force

HUANG Yun-mi¹, ², CAI Jian-qiu¹, ², LUO Hai-jun¹, ²

College Physics. 2021, 40(11): 21. doi:10.16854 / j.cnki.1000-0712.210254

Abstract ( 692 )

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The measurement of traditional magnetic field and Ampere force are carried out on

completely inde- pendent experimental instruments. In this paper，Arduino MCU and Hall sensor

are applied to university physics experimental instruments，and a kind of comprehensive

instrument is designed and manufactured to measure the distribution of magnetic field and

the Ampere force caused by the current carrying circular coil，Helmholtz coil and Hall sensor. The

magnetic induction intensity and Ampere force can be read through the display screen

directly， conveniently and fast. The experimental teaching principles and contents of studying the

influence factors of magnet- ic field distribution and Ampere force are expanded，which is helpful

for students to deepen their understanding of the application and practice of physical

knowledge，cultivate students’innovative thinking and stimulate their inter- est in learn.

Exploration and practice of college physics teaching based on portable demonstration experiment

QIN Zhe¹, YANG Guang-wu², HU Xue-lan¹, LU Xiao-cui², MA Zeng-hong²

College Physics. 2021, 40(11): 26. doi:10.16854 / j.cnki.1000-0712.210026

Abstract ( 606 )

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Firstly，through the investigation and analysis of the current situation of

demonstration experiment in colleges and universities，it is found that most of the science and

engineering colleges and universities have less class hours，low utilization rate，and can not

achieve the desired teaching effect. Secondly，it is proposed that teachers should

constantly carry out the innovation and practice of teaching ideas. According to the

characteristics of their own teaching in colleges and universities，the portable classroom

demonstration experiment instrument is de- veloped and designed，and the portable classroom

demonstration experiment system is constructed. Finally，taking the portable wave optics

demonstrator used in the teaching process of single slit diffraction of wave optics in the sec- ond

semester of the junior year as a teaching case，the role of physics demonstrator in the daily

teaching of cultiva- ting students' physical thinking and innovation ability is expounded

Physics courses in European universities

LI Zu-bin, YAN Xiao-qing, SONG Feng

College Physics. 2021, 40(11): 31. doi:10.16854 / j.cnki.1000-0712.210136

Abstract ( 634 )

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Under the new requirements of the new century，general physics coureses in university

need to be reformed. As the birthplace of modern universities，physics coureses in

European universities are examples that should be referred to. In this paper the setting of

physics courses and their credits in high-level universities in Eu- rope are investigated. The

statistical results show that physics courses are still the basic general courses for most sci-ence disciplines in most universities. For different disciplines，more flexible and reasonable settings might be the di- rection of future reformation of general physics coureses.

Design and practice of ideological and political education in the teaching of electromagnetic field and electromagnetic wave

SONG Ling-ling, HUANG Wen

College Physics. 2021, 40(11): 36. doi:10.16854 / j.cnki.1000-0712.210201

Abstract ( 1832 )

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Based on Gauss theorem in electromagnetic field and electromagnetic wave，in this paper

the design of teaching with teachers as the main body is carried out，in which there are five

teaching links: introduction，es- tablishment，breaking，extension and conclusion，so as to realize

the teaching conception of knowledge inheritance and ability migration. Integrating the ideological

and political elements into the curriculum from three dimensions not only solve the teaching

difficulties，such as determining the size of the spatial angle，the key meaning of

positive and negative，and the calculation of the spatial angle of closed surface，but also guide

students to see problems from multiple perspectives，and help students to establish a correct

outlook on life，values，and the world，so as to real- ize the goal of condensing the knowledge in the

value dissemination and realizing value guidance in the knowledge dissemination.

Lessons learnt from online teaching during covid-19 pandemic on the development of mixed first-class curriculum —based on the data analysis of students' learning experience

CHE Xiao-qi, HUANG An-ping, JIN Shuo, CHEN Zi-yu, YE Zhan-hong

College Physics. 2021, 40(11): 41. doi:10.16854 / j.cnki.1000-0712.210209

Abstract ( 733 )

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Online teaching is an emergency education strategy that maintains the continuation of

teaching and learning during the COVID-19 pandemic. In this paper the online teaching experience in

physics college in Beihang University during the pandemic is summarized and data from four surveys

and interview contents of students' online learning experience is analyzed. The results show that

there are significant differences in students' learning experi-ence ( such as the frequency of teacher-student interaction，learning pressure，etc.) between online and in-person learning which varied with the learning time. The interactive design of online teaching and the scientific evaluation are highly approved by students，that fully expect to engage in the mixed online and in-person teaching after retur- ning to school. This large-scale

online teaching practice is consistent with the basic principles of the first-class cur- riculum development in terms of innovation of teaching methods，improvement of learning challenges，and helping students achieve the high-level learning goals. The feedback from students also serves as an excellent guide for the development of the first-class courses.

Measurement of rigid body inertia tensor using gyroscope sensor on a mobile phone

LOU Chen-xuan, ZHOU Jing-lin, ZHENG Xue-yao, LIU Ke-wei, LUO Dan-nan, BAI Zai-qiao

College Physics. 2021, 40(11): 48. doi:10.16854 / j.cnki.1000-0712.210079

Abstract ( 808 )

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By using a gyroscope sensor and phyphox software，the angular velocity curve of a free

falling mo- bile phone is recorded. Then，up to a scale constant，the inertia tensor of the

phone is determined based on the conservation of orbital angular momentum and kinetic energy

in the center-of-mass reference frame. Depending on whether vanishing off-diagonal elements is or

not assumed，two algorithms are proposed to calculate the inertia ten- sor. The results are

confirmed by substituting it into the Euler equation for recoded trajectories.

Dynamics of active Brownian particle with internal energy depot

QIU Xing, YANG Zi-bei, XIA Shi-qi, WANG Hai-yan

College Physics. 2021, 40(11): 53. doi:10.16854 / j.cnki.1000-0712.210014

Abstract ( 608 )

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In the paper，the dynamics of active Brownian particle with internal energy depot is

investigated by numerical simulation. First，for the free potential case，the results show that

active Brownian particles do not per- form directed motion and the mean squared displacement of

active Brownian particle is a nonlinear function of time. Then in the harmonic potential case，we

find that the free diffusion of particle is restricted and the range of diffusive motion of active

Brownian particle is larger than that of passive Brownian particle during the same time interval.

At last，for asymmetric period potential we calculate the distribution of the displacement of the

active Brownian particle and the averaged velocity of the active Brownian particle change in time

with different potential barriers. The results show whether or not active Brownian particle is

able to transfer the depot energy into directed motion depends on the height of asymmetric

potential barrier.

Virtual experiment system of potentiometer based on LabVIEW

LI Wen-tao¹, SUN Qian-qian¹, LU Chen-ling¹, YU Ming-zhou²,

College Physics. 2021, 40(11): 59. doi:10.16854 / j.cnki.1000-0712.210194

Abstract ( 810 )

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In order to help students to learn physics experiment courses online and realize the

online examina- tion of experimental operation，virtual simulation experiment of measuring

electromotive force with eleven-wire po- tentiometer is designed and developed on LabVIEW

platform，which can fully simulate all functions of the actual in- strument. The operating steps and

experimental precision of the virtual simulation experiment software are consistent with those of

the experimental instrument used in our school. Meanwhile，the virtual instrument is also

equipped with operational tips and instructions，which can help students preview and review the

experimental principles and process on the computer. The packaged software can be completely

detached from the programming platform and be used on other computers without the need for

pre-installed software. The experimental principle，the design method of the virtual instrument

and the selection basis of the parameters are described in detail，and the programming

block diagram of the system is provided.

Diffraction and splitting function of phase grating

ZOU Yi-yun, LIN Jia-li, LU Yue-yuan, YAN Xiao-na

College Physics. 2021, 40(11): 64. doi:10.16854 / j.cnki.1000-0712.210104

Abstract ( 2989 )

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Using the coherent superposition，diffractions are deduced when a plane wave incidents on

a phase grating. Results show that the ±1 order diffraction of the phase grating can get the

maximum intensity and realize the splitting function，overcoming the problems in amplitude grating

where the 0 order diffraction has the maximum in- tensity but with no splitting function. The

diffraction efficiency of ±1 order diffraction with respect to the duty ratio and phase introduced

by the phase material are discussed. The method we provided here has implicit physical mean- ings

and is easy to adapt to other diffraction structure.

Analysis of rainbow from the perspective of wave optics

JIA Jia-qi, HUANG Zhen, XU Qing-ying, WU Qing-lin

College Physics. 2021, 40(11): 69. doi:10.16854 / j.cnki.1000-0712.210114

Abstract ( 1260 )

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Rainbow is a common natural phenomenon. In optical teaching，Fermat principle

is the general method for rainbow angle deduction. Nevertheless，this paper explores the

principles and features of rainbow from the perspective of wave optics by calculating the

intensity of the primary and secondary rainbow quantitatively using Fresnel formula.

Furthermore，we give the theoretical explanation of the rainbow angle and prove that

rainbow is partial polarized light.

Principle and experimental verification of mirage formation

HAN Run-ze

College Physics. 2021, 40(11): 74. doi:10.16854 / j.cnki.1000-0712.210046

Abstract ( 624 )

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This article studies the principle of mirage formation in nonlinear index

gradient fluids. Based on Snell's law，the optical path model is established. On this basis，the

optical path and mirage imaging law are simu- lated with MATLAB. A solution with negative

exponential gradient of refractive index in the vertical direction is con- figured，and the actual

optical path is obtained by irradiating the solution with laser. The data points of optical path

are extracted by tracker software，and the data are analyzed by MATLAB. The experimental

optical path function and imaging position are consistent with the prediction results of Snell's

law. We also analyze the rationality of neg- lecting the secondary factors in the experiment，which

shows that Snell's law is reasonable The law explains the cor- rectness of mirage formation.

Exploration of the sinking of Saxon bowl: correction of simple harmonic vibration

WANG Xing¹, ², LI Qiu-hang¹, HOU Ji-xuan¹, CHEN Qian¹

College Physics. 2021, 40(11): 80. doi:10.16854 / j.cnki.1000-0712.210095

Abstract ( 1094 )

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Starting from the correction of harmonic vibration，theoretical analysis and

experimental exploration on the sixth topic Saxon bowl of IYPT2020 are carried out. This topic

describes a fact that the ancient Saxons used the bowl with holes on bottom to tell the time. Such

a bowl sinking model can be used as a vivid case to enhance students' understanding of simple

harmonic vibration and damped vibration. In this way，the complicated formula derivation is avoided

and the simple equation is obtained. By using computer to solve the differential equation

and doing experi- ments，the feasibility of the theory is proved and the influence of some

factors on the sinking time is studied

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