Loading...

Table of Content

    20 December 2025 Volume 44 Issue 10
      
    Entropy conservation and entropy increase of ideal gas system on a ring
    Hai-Jun Zhou
    College Physics. 2025, 44(10):  1.  doi:10.16854/j.cnki.1000-0712. 250383
    Abstract ( 106 )   PDF (201KB) ( 81 )  
    Related Articles | Metrics
    The entropy of microscopic configurations of a classical ideal gas system located on a one-dimensional ring is investigated. It is verified that the distribution of particles on the ring becomes more and more uniform,and the positional entropy increases with time toward the maximum value,while the total entropy (contributed by positional uncertainty and velocity uncertainty) is conserved in the rigorous mathematical sense. The velocities of particles which are passing through the same position at the same time become more and more quantized,and the gap between adjacent discrete velocity values gradually reduces to zero as time increases. This quantization property means that,as the velocity resolution limit of an observer must be finite in the sense of physical measurement,the measured entropy of microscopic configurations must be increasing with time. This simple system is helpful for understanding the second law of thermodynamics.

    Bullogh-Dodd model undercelestial holography
    ZHAO Zi-Jian, FAN Wei
    College Physics. 2025, 44(10):  6.  doi:10.16854/j.cnki.1000-0712.250010
    Abstract ( 64 )   PDF (224KB) ( 27 )  
    Related Articles | Metrics
     In this paper, we firstly review the celestial holographic. Then we apply celestial holography to the 2d Bullough-Dodd model. We compute the conformal correlator dual to the 2d scattering amplitude of the Bullough-Dodd model at the leading order, and verify its unitarity.


    The Nernst equation without additional assumptions and its interpretation
    WANG Yuan1, 2, ZHOU Ying-hui2, CHEN Jin-can2
    College Physics. 2025, 44(10):  11.  doi:10.16854/j.cnki.1000-0712.240571
    Abstract ( 61 )   PDF (150KB) ( 26 )  
    Related Articles | Metrics
    A new thermodynamic function is introduced and the curve of the function varying with temperature is simulated by using the experimental data of the enthalpy and Gibbs function changes during the isothermal and isobaric process of low temperature thermodynamic systems. The Nernst equation is obtained directly by extrapolating the experimental simulation results to absolute zero without introducing additional assumptions. It is pointed out that the Nernst equation without additional assumptions should be called the Nernst statement instead of the Nernst theorem, and can be the core content of the statement of the third law of thermodynamics. Moreover, the physical connotations of the Nernst equation are explained more accurately.

    Further discussion on the relation between the electric displacement  vector D and polarization charges
    SONG Li-tao1, HE Jie2, WANG Jie-fang1
    College Physics. 2025, 44(10):  14.  doi:10.16854/j.cnki.1000-0712.250105
    Abstract ( 77 )   PDF (211KB) ( 62 )  
    Related Articles | Metrics
    In the teaching of electromagnetism, it is often asked whether the electric displacement vector D is related to the polarization charge. In this paper, the relation between the electric displacement vector D and the polarization charge is further discussed based on the viewpoints and arguments presented in previous literatures. The results demonstrate that due to the constraint relationship between free charges and polarization charges, it is inaccurate to simplistically state that the electric displacement vector D is either related or unrelated to polarization charges. The “conditions under which D is independent of polarization charges” proposed in previous literature should be more appropriately termed as “conditions under which the distribution of polarization charges does not affect the original distribution of free charges”.



    A probability theory Solution of the free electronic gas problem in the metal
    FU Qiang
    College Physics. 2025, 44(10):  18. 
    Abstract ( 58 )   PDF (224KB) ( 30 )  
    Related Articles | Metrics
    This study regards the allowable momentum value of the free electronic gas in the metal (px,py,pz) as a three-dimensional random variable which obey the uniform distribution. Meanwhile, This study use probability knowledge to solve the problem of free electronic gas in the metal. It helps students to establish intuitive physical landscape and understand the relevant concepts of free electronic gas models in metal.


    The main methods for quasi exact solvable systems
    SHI Jiaxuan, QU Feiyang
    College Physics. 2025, 44(10):  22.  doi:10.16854/j.cnki.1000-0712.240477
    Abstract ( 56 )   PDF (193KB) ( 24 )  
    Related Articles | Metrics
     Reviewed the research history and main methods of quasi exactly solvable systems The QES system falls between precisely solvable and unsolvable systems and is capable of solving some eigenvalues and eigenstates under specific conditions The research began with the Razavy potential and gradually developed through Lie algebra, Heun equations, supersymmetric quantum mechanics, and the Bethe Ansatz method These analytical tools reveal the symmetry and complex structure of QES systems, expanding the scope of solvable models The article also discusses the application of pre potential methods and possible future research directions for QES systems, including non Hermitian quantum systems and experimental verification The research on QES system has a profound impact on multiple fields of physics


    Comparative study onnumerical solutions of Schrdinger #br# equation under different forms of δ potential wells#br#
    YANG Dongcheng1, ZHANG Erhu1, SHEN Yeqi1, FANG Aiping1, LI Rong1, JIANG Chenwei1, ZHANG Xiuxing2, WANG Xiaoli1
    College Physics. 2025, 44(10):  29.  doi:10.16854/j.cnki.1000-0712.250151
    Abstract ( 69 )   PDF (306KB) ( 32 )  
    Related Articles | Metrics
    The delta potential well is an important idealized model in quantum mechanics, which has significant applications in understanding quantum tunneling phenomena and describing the scattering of electrons by impurities This article selects four common approximate expressions of the delta function in literature. Numerical methods are used to solve the Schrdinger equation corresponding to different function forms in the delta potential well. The numerical results are compared with the theoretical results in terms of wave function, energy eigenvalues, and wave function derivatives Research has found that among the four common approximate expressions of the δ function in literature, the function δ(x)=limk→∞kπe-(kx)2 can better replace the δ function for numerical operations. The wave function, energy eigenvalues, and wave function derivatives obtained from numerical calculations are very close to theoretical results, and the accuracy of the numerical solution corresponding to the δ function potential well approximation expression increases with the increase of parameter k. This proves that the method of numerically solving the Schrdinger equation under the δ potential well by constructing an approximation function is feasible.


    Experimentaltest system of metal ball pendulum based on wireless power transfer#br#
    GUO Huaxiang, WANG Liwei, ZENG Zilun, WU Jingqi, XU Jianchun, BI Ke
    College Physics. 2025, 44(10):  34.  doi:10.16854/j.cnki.1000-0712.240510
    Abstract ( 63 )   PDF (320KB) ( 21 )  
    Related Articles | Metrics
     In recent years, wireless power transmission (WPT) has been widely applied in various fields such as energy, medical, and communication, becoming a research hot spot in the electromagnetic domain. Compared to wired transmission, WPT offers greater flexibility and safety; however, issues like high costs for equipment replacement and maintenance still exist. This paper presents the design and implementation of a wireless energy communication system utilizing Universal Software Radio Peripheral (USRP) technology, along with the development of a counting device for metal detection based on electromagnetic induction principles. Through a pendulum experiment, the system successfully monitored and recorded the oscillation behavior of a metal ball, demonstrating its feasibility and effectiveness in detecting metallic targets. Additionally, this paper explores the extensive application potential of USRP in signal processing and communication systems, highlighting its advantages in enhancing system flexibility and performance.


    Research on MicroMagnetic Field Measurement Based on Moiré Fringe Technology
    SHEN Huijuan, WU Jinghua, LAN Shenni, YU Yitong, LAI Hansen, LU Xuewei, HAN Taikun
    College Physics. 2025, 44(10):  39.  doi:10.16854/j.cnki.1000-0712.250043
    Abstract ( 66 )   PDF (322KB) ( 31 )  
    Related Articles | Metrics
    Micromagnetic field measurement has shown significant application value in many scientific fields. However, existing instruments for physics experiments in university are relatively rigid, limiting students' opportunities to conduct further experimental exploration. By leveraging the amplification characteristics of Moiré fringes, the variation patterns of Moiré fringes under magnetic fields was observed and established a quantitative relationship between them, enabling micromagnetic field measurement based on Moiré fringe technology. Furthermore, by modifying the grating constant, the influence on the measurement results was investigated. The Image J software was utilized to collect and analyze image data, optimizing the micromagnetic field measurement system based on Moiré fringe technology. This measurement method offers the advantages of visualization, ease of operation, and straightforward equipment assembly, enables students to both understand the characteristics of micromagnetic fields and pursue extended research projects.

    Exploration on the curriculum reform of “Open Physics Experiments” for cultivating outstanding students
    HUANG Zhencheng, FENG Raohui, TANG Jian, SHEN Han, LUO Xin, CHEN Yu, LIAO Deju, FANG Yizhong, CUI Xintu, PANG Xiaoning, LI Mengyu
    College Physics. 2025, 44(10):  44.  doi:10.16854/j.cnki.1000-0712.240599
    Abstract ( 48 )   PDF (220KB) ( 25 )  
    Related Articles | Metrics
    Plan for Cultivating Outstanding Students in Basic Disciplines is an exploration in China to independently cultivate top talents towards the international outstanding level. In order to achieve the goal, we set up the course “Open Physics Experiment” by combining the self-design experiment with the critical thinking in the class, and develop different scientific research skills in the training program. This paper gives a comprehensive introduction to the course, its reform and innovation measures in the teaching concept, goal, method, arrangement, and assessment. It analyzes the positive influence of the curriculum on the cultivation of students' capabilities and the improvement of scientific research accomplishment, as well as the teaching results obtained. Our experience might offer valuable examples and ideas for similar cultivating outstanding students programs.


    Analysis of research status and hotspots of university physics #br# experiment teaching based on CiteSpace
    ZHOU Xiaoyun, YANG jie
    College Physics. 2025, 44(10):  49.  doi:10.16854/j.cnki.1000-0712. 240514
    Abstract ( 56 )   PDF (289KB) ( 20 )  
    Related Articles | Metrics
     Based on CiteSpace visualization analysis software and bibliometric methods, 3426 articles related to University physics experiment teaching research included in China National Knowledge Infrastructure from 2014 to 2024 were selected as the research object.From the perspective of the number of published articles and the authors, the research on college physics experiment teaching has been continuously deepened in the past 10 years, and the authors have a relatively stable cooperative relationship based on "class relationship".From the graph of the issuing institutions, the research of each institution is relatively independent, and it is necessary to strengthen cooperation and exchange between schools and enterprises to build a high-quality resource sharing system.From the perspective of research hotspots, we can strengthen curriculum teaching research from three aspects in the future,the first is to further improve the teaching content system, highlighting the cultivation of inquiry ability and innovation ability;the second is to strengthen the integration of new technologies and new means in teaching methods and means, open up a new track of education development, and shape new advantages of education development; the third is to support the macro vision of talent cultivation, grasp the needs of students 'ability cultivation,strengthen the top-level design of the course.


    Innovative research on teaching of electromagnetic waves obliquely #br# incident on three-layer media#br#
    TAN Zhen
    College Physics. 2025, 44(10):  55.  doi:10.16854/j.cnki.1000-0712.240586
    Abstract ( 42 )   PDF (221KB) ( 22 )  
    Related Articles | Metrics
    Consider the propagation of parallel polarized waves of plane electromagnetic waves obliquely incident on a three-layer medium. Based on the cognitive model of physics problem-solving and electromagnetic field theory, the reflection and transmission coefficients under arbitrary conditions are derived, and the formulas for reflection and transmission coefficients under normal incidence in textbooks such as electromagnetic fields and waves are extended. Several special conclusions are discussed in specific situations, which can enrich the content of the textbook and prepare for future updates on electromagnetic fields and waves. This has positive significance for cultivating college students' innovative consciousness and research ability, and also provides innovative teaching research cases for science and engineering teachers to conduct teaching research.

    Classroom Teaching Practice of College Physics Based on the ETA Physics Cognitive Model——Taking “Newtons Rings” as an example#br#
    ZHOU Yaling, YANG Fan, ZHANG Jianqiao, WANG Zhong, XIA Bin
    College Physics. 2025, 44(10):  60.  doi:10.16854/j.cnki.1000-0712.240596
    Abstract ( 51 )   PDF (290KB) ( 27 )  
    Related Articles | Metrics
    This paper is based on the ETA Physics Cognitive Model, Taking “Newtons Rings” as an example, starting from the experimental physics cognition (E), moving on to the theoretical physics (T) cognitive level, and then further delves into the applied physics (A) cognition. The three-level structure from the surface to the core, reconstructs the teaching content, optimizes the teaching process, and constructs a classroom teaching model that combines virtual - theoretical and practical aspects. Also, in line with the requirements of integrating ideological and political education into the college physics curriculum, it trains students physical thinking, helps them understand the spirit of physics, and appropriately cultivates students entire process of physical cognition. Practice shows that the teaching model built based on the ETA Physics Cognitive Model has achieved remarkable results. In class, students active participation has increased significantly, their enthusiasm has been enhanced, and their problem-solving ability after class has improved obviously.

    Research on Electromagnetic Teaching under the integration of science #br# and education-Topological origin of Ampères circuital law#br#
    WANG Xiaoran, Li Chunmi, ZHAO Xiaoming, YANG Mingchao, KOU Supeng
    College Physics. 2025, 44(10):  64.  doi:10.16854/j.cnki.1000-0712.240572
    Abstract ( 42 )   PDF (254KB) ( 29 )  
    Related Articles | Metrics
     In the context of the integration of science and education, integrating the concepts, methods, and processes of scientific research into undergraduate teaching is an effective way to cultivate top-notch innovative talents with open thinking, innovative spirit, and innovative ability. Accurately finding the connection point between textbook knowledge and scientific research content is the key to its implementation. This article takes Amperes circuital law in electromagnetics as an example and finds that its proof process is naturally appropriate for the topological concept of the number of loops. Explore the topological origin of Amperes circuital law and clarify the topological essence of magnetic field integral loop fine-tuning invariance.Enable students to have a profound understanding of Amperes circuital law and vector field properties, while also gaining a preliminary understanding of topology knot theory.At the same time, in tracing the formation of scientific knowledge, understanding the spirit of scientific inquiry, mastering scientific inquiry methods, and subtly cultivating students innovative spirit and ability. This provides effective methods and examples for integrating the concepts, methods, and processes of scientific research into classroom teaching in universities.

    Constructing a new ecology of college physics teaching under the background of informationization#br#
    SHI Shunping1, Song Yong1, Diao Kai2, Li Xia1, Lei Dan1, Zhao Xiaofeng1
    College Physics. 2025, 44(10):  69.  doi:10.16854/j.cnki.1000-0712.240575
    Abstract ( 47 )   PDF (407KB) ( 16 )  
    Related Articles | Metrics
    Under the background of digital informationization, traditional teaching has changed to mixed teaching, teaching content has changed from textbook text to network resources, the connotation and extension of teachers preaching, teaching and solving doubts are constantly expanding, and teachers have changed from the leading role to the guiding role. The physics teaching team of Chengdu University of Technology focused on the pain points in teaching and carried out the reform of intelligent teaching mode. By optimizing the curriculum system, self-made micro-course video, knowledge expansion, knowledge sharing, self-made animation, etc., the team independently created SPOC and MOOC courses, constructed a new teaching ecology under the background of informatization, created a golden course of college physics, and successfully approved provincial online and offline hybrid first-class courses.


    Historical origin and developments of rational mechanics and theoretical mechanics#br#
    CHEN Liqun
    College Physics. 2025, 44(10):  75.  doi:10.16854/j.cnki.1000-0712.240459
    Abstract ( 51 )   PDF (134KB) ( 39 )  
    Related Articles | Metrics
    The historical development of rational mechanics and the name changes of general courses in mechanics are investigated. Rational mechanics, the branch of mechanics based on rigorous mathematical demonstrations and proofs, reached its peak in the 19th century under the guidance of French scholars and declined in the first half of the 20th century. It was rejuvenate in the mid-20th century under the advocacy of American scholars. In China, rational mechanics began in 1980s and has continued to develop since then. In the 19th century, the mechanics textbooks focusing on theoretical issues in French were named rational mechanics, and it is still used in general textbooks in French and Italian. Theoretical mechanics possibly derived from rational mechanics is widely used as the titles of general textbooks in Russian and Chinese, as well as occasionally used in English and German for textbooks or treatises.

    Research on quantum tunneling problem based on onedimensional #br# GrossPitaevskii equation#br#
    WU Jianan1, FANG AipinLIU Yuhao1, SHI Chengyu1, LI Rong1, JIANG Chenwei1, ZHANG XiuXing2, WANG Xiaoli1
    College Physics. 2025, 44(10):  80.  doi:10.16854/j.cnki.1000-0712.250174
    Abstract ( 57 )   PDF (468KB) ( 31 )  
    Related Articles | Metrics
    We utilized the splitoperator method to numerically solve the onedimensional GrossPitaevskii equation. The quantum tunneling time was defined as the time difference corresponding to the maximum value of the modulus square of the wave function when entering and exiting the barrier. We obtain the tunneling time and tunneling probability of its bright soliton solution through a Gaussian potential barrier of a certain width at different energies. It was observed that when the incident energy is less than the barrier height,the tunneling time increases with the incident energy. When the incident energy is greater than the barrier height,the tunneling time is inversely proportional to the tunneling velocity. Furthermore,within different energy ranges,the effects of the oscillation frequency of the barrier on the quantum tunneling time and probability were studied when the barrier undergoes smallamplitude oscillations. It is observed that under the quantum state with incident energy less than the barrier height,different barrier oscillation frequencies caused significant oscillations in the tunneling time.

    Study on the characteristics of interference patterns of Fresnels Biprism
    SONG Xueyang, ZHANG Ruixuan, LI Sicheng, Yu Xiaochong BAI Zaiqiao
    College Physics. 2025, 44(10):  89.  doi:10.16854/j.cnki.1000-0712.240512
    Abstract ( 67 )   PDF (558KB) ( 41 )  
    Related Articles | Metrics
    The interference pattern of Fresnels biprism is recorded by a CMOS camera and converted to intensity distribution curve. It is found that the envelope of the interference fringes fluctuates regularly in the central region and decays rapidly on both sides, two features cannot be observed in the classic double-slit interference pattern. To explain this phenomenon, a simple model is proposed that take the straight-edge diffraction at the ridge of the biprism into consideration. By MATLAB simulation, light intensity distribution matching the observed characteristics is obtained. The model also implies that the spacing between interference fringes gradually narrows in the diffraction regions on both sides. Moreover, the relationship between the number and visibility of interference fringes in the central region with the slit width and the position of the biprism is studied. All the results are in good agreement with the experiment measurements.


    Multitechnical integration experiment for measuring the young s modulus  of metal wires: improvements and precision enhancement
    HUANG Shuqi, LI Yuke
    College Physics. 2025, 44(10):  96.  doi:10.16854 /j.cnki.1000-0712.250026
    Abstract ( 56 )  
    Related Articles | Metrics
    The conventional experimental setup of Youngs modulus measurement based on optical lever method has been believed to exhibit some disadvantages such as high operational requirements and relatively low data accuracy, making it difficult to meet the needs of highquality teaching. Here, we employed a new method to improve the traditional experimental setup through using air wedge instead of optical lever, thereby this setup is characterized by its integrated design, which saves space. A pulley is added to change the direction of the wedge angle, which expands the angle and increases the measurement range. In addition, a vernier caliper is designed to improve the measurement accuracy of the metal wire.

    Conductivity of stretchable carbon nanotubes
    JIANG Haolin, XI Shu, Wang Yinshu, WANG Aiji
    College Physics. 2025, 44(10):  101.  doi:10.16854/j.cnki.1000-0712.240453
    Abstract ( 35 )   PDF (249KB) ( 15 )  
    Related Articles | Metrics
    This paper discusses the relationship between the resistance of stretchable elastic wires, made by injecting water-based carbon nanotube slurry into rubber tubes, and the bending angle and stretching length of the wires under two conditions: bending and straight stretching. Experimental results show that, under straight stretching, the change in resistance has a strong linear correlation with the stretching length. Under bending, a functional relationship is also observed. This paper attempts to explain these patterns using conductive channel theory and quantum tunneling effect. After establishing the relationship between the degree of bending and stretching of the wire and its resistance, the wires changes can be measured by its resistance in practical applications. This offers broad potential for applications in robotics, flexible electronics, wearable devices, and more.

    The calculation of the electric multipole potential and field strength and their  physical essence
    DONG Xianghao1, WANG Nengchao2, 1
    College Physics. 2025, 44(10):  111.  doi:10.16854/j.cnki.1000-0712.240526
    Abstract ( 64 )   PDF (415KB) ( 36 )  
    Related Articles | Metrics
    This paper presents a method for calculating the potentials and electric field strengths of higher-order electric multipoles based on known electric multipole potentials. The method employs simpler mathematical techniques by using known multipoles as a reference. Through coordinate transformation, the potential of newly constructed electric multipoles is expressed in terms of the known multipole potentials. Traditional methods for calculating the electric potential and field strength of electric multipoles often rely on complex mathematical operations and cumbersome derivations, limiting their flexibility and efficiency in practical applications. Additionally, such methods pose challenges for lower-level students with limited mathematical knowledge to learn and understand. The proposed calculation method offers a clear physical picture, which also aids in deepening the understanding of the physical nature of electric dipoles and electric dipole moments.

    Accurate measurement of small electric charges based on digital speckle pattern interferometry
    YI Jiaxiong, YAO Chuansen, FANG Xiongjun
    College Physics. 2025, 44(10):  111.  doi:10.16854/j.cnki.1000-0712.240546
    Abstract ( 48 )  
    Related Articles | Metrics
    This paper proposes a noncontact optical measurement method based on digital speckle pattern interferometry (DSPI) to achieve precise quantification of small charges. By investigating the electric field distributions in parallelplate capacitor systems and analyzing the forces acting on charged objects, the challenge of charge measurement is converted into a problem of angular deflection detection. Leveraging the diffuse reflection characteristics of a ground glass plate, speckle patterns are captured using a CCD sensor. Through sequential grayscale conversion, Fast Fourier Transform (FFT) processing, and phase extraction algorithms, the interference fringes of speckles are reconstructed, thereby enabling noncontact charge measurement. The developed system achieves precise measurements of charges ranging from 0.1 nC to 1.0 nC under standard laboratory conditions, showing high consistency with simulation results. This work establishes a novel strategy for contactless precision measurement of small charges.



    Discussion on the error caused by the position difference between virtual and  real light sources in the double prism interference experiment
    HANG Jiasheng1, WANG Liying1, 2, JIN Chao1
    College Physics. 2025, 44(10):  117.  doi:10.16854/j.cnki.1000-0712.250005
    Abstract ( 52 )  
    Related Articles | Metrics
    The slit (real light source) and the virtual light source are not on the same plane, which is a commonly overlooked problem in measuring the wavelength of light using Fresnel prism interferometry. The principle of measurement error caused by this problem is explained and the process for calculating the associated error values is derived. The analysis indicate that the relative error caused by replacing the virtual light source plane with a slit plane is less than 0.01%, which is significantly smaller than other systematic errors in this experiment. Therefore, in experiments, it is common to approximate the position of the slit plane as the position of the virtual light source plane to measure the distance to the observation screen, neglecting the measurement errors caused by the non-coplanarity of the virtual and real light sources.