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Theoretical teaching of the work done by inertia  forces and its practical applications  CHEN Chi-yi College Physics    2024, 43 (11): 26-.   DOI: 10.16854/j.cnki.1000-0712.240156 Abstract （1517）      PDF（pc） （548KB）（644）       Knowledge map    Save This article addresses the calculation of the work done by inertia forces in the teaching of theoretical mechanics. It introduces an equivalent description of inertial forces based on the physics of reference frames. Based on this, the work done by inertia forces is re-examined. Firstly, Newtonian dynamics can be cleverly derived to yield an inevitable description that can be directly applied in a translational (non-rotating) reference frame by applying Newtonian dynamics to the reference object of the reference frame. Therefore, the theoretical expression for inertial forces is obtained through the real force acting on the reference object. Secondly, the traditional form of Newtonian dynamics can in principle be generalized to any translational reference frame and still holds by simply replacing the force terms from full to relative forces. Thus, it leads to a new approach for calculating the work done by the inertial force. Finally, as a check, the typical pedagogical topic of work done by inertial forces was re-examined and self-consistent results were obtained.  Related Articles | Metrics | Comments（0）

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The four distinct comings of Planck's constant h CAO Ze-xian College Physics    2024, 43 (11): 1-.   Abstract （1376）      PDF（pc） （1040KB）（986）       Knowledge map    Save Planck’s constant h, the tag of quantum theory, is one of the universal physical constants. The various distinct comings of Planck’s constant include the derivation of Plank’s spectral distribution formula for black-body radiation, Einstein’s interpretation of the experimental results concerning photoelectric effect, quantization of phase space by Planck (and also by Bohr and Bose), and Schrdinger’s effort to rescue the unified theory of gravity and electricity by Weyl, in which the role of the constant h is either simply a prefactor to make hν of the same dimension as energy or to make hν/kT dimensionless, a quantum of action per se,the volume element of the phase space or the angular momentum, or the energy quantum for light in the form of h , or a factor in the wave theory in the form of ih or i.The distinct comings of the Planck’s constant in the quantum theory rightly justifies its universality.By the way, neither Planck nor Einstein had introduced any revolutionary ideas by applying the energy quantum  h. Related Articles | Metrics | Comments（0）

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Attosecondpulse laser and electron dynamics-interpretation of Nobel Prize in Physics 2023 WEI Bo-ning1, 2, WANG Li-feng3 College Physics    2024, 43 (11): 7-.   DOI: 10.16854/j.cnki.1000-0712.240349 Abstract （1083）      PDF（pc） （1056KB）（1538）       Knowledge map    Save The Nobel Prize in Physics 2023 was awarded to three experimental physicists, for their tremendous contribution to "experimental methods that generate attosecond pulses of light for the study of electron dynamics in matter". For the significance and applications of attosecond pulse laser, this paper is organized by the development of human exploration on ultrafast dynamics, the principle and experimental methods of generation and measurements of attosecond pulse laser, typical applications of attosecond pulse laser and future perspectives. Related Articles | Metrics | Comments（0）

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Slant motion considering air resistance YANG Yang College Physics    2024, 43 (12): 11-.   DOI: 10.16854/j.cnki.1000-0712.240086 Abstract （1034）      PDF（pc） （902KB）（614）       Knowledge map    Save Considering air resistance and buoyancy, the law of slant motion of the object is studied by numerical solution, including the relationship between range and projecting angle, the relationship between the optimal projecting angle. In addition, the relationship between projecting angle and maximum motion height as well as motion time are also studied. Related Articles | Metrics | Comments（0）

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New research on the quantum tunneling of photons College Physics    2024, 43 (12): 5-.   DOI: 10.16854/j.cnki.1000-0712.240168 Abstract （920）      PDF（pc） （506KB）（422）       Knowledge map    Save Traditionally, the single-barrier photonic quantum tunneling has been studied via a formal analogy between the Helmholtz equation of electromagnetic waves in a waveguide or total internal reflection and the stationary Schrdinger equation of a massive particle in a single barrier, from which the tunneling probability of photons is directly obtained without taking into account the physics of the electromagnetic field itself, such that it is neither strict nor complete. More importantly, so far, the quantum resonance tunneling effect of photons passing through a multi-barrier has not been systematically studied. In this paper, starting from the physics of the electromagnetic field itself, a strictly theoretical model for photonic quantum tunneling through a single barrier is established, and some new results are obtained. Further, the quantum tunneling of guided photons through a multibarrier is studied, where the analytical expression of photonic tunneling probability is obtained, based on which the quantum resonance tunneling effect of photons and its physical characteristics are studied. A preliminary study of controlling light with light based on the photonic resonanct tunneling is presented. Related Articles | Metrics | Comments（0）

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Fluid mechanics analysis of the formation process of the tip of ice-cream JIN Zi-lu, LU Shen-yi, PENG Shi-xiang College Physics    2024, 43 (11): 74-.   DOI: 10.16854/j.cnki.1000-0712.240015 Abstract （908）      PDF（pc） （828KB）（430）       Knowledge map    Save Based on Poiseuille’s theorem, the formation model of ice cream is established to explain the phenomenon that the tip of the cone produced by the ice cream machine often forms a pointed protrusion. We assume that the raw material of ice cream is a homogeneous, incompressible, but viscous fluid. After analyzing the temperature change during the production process and operator’s manipulation, we confirm the rationality of the hypothesis of the formation model. Using computer simulation software to simplify the model, the formation process of the tip of the ice cream is concluded, that is, the ice cream is subjected to the least viscous resistance in the center of the flow tube, and it is easier to fall than other positions, and finally the tip of the ice cream is formed. The establishment of this model and the exploration of the principle can better understand and apply the principle of fluid mechanics, better understand the phenomena in life and promote the progress of industrial production. Related Articles | Metrics | Comments（0）

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The triumph of statistical physics andemergentism SHI Yu College Physics    2025, 44 (1): 1-.   DOI: 10.16854/j.cnki.1000-0712.240554 Abstract （894）      PDF（pc） （1108KB）（296）       Knowledge map    Save We introduce the achievements for which 2024 Nobel Prize in Physics was awarded，and describe the scientific background，history，current status and future，emphasizing the physical implications and biological sources，exposing the connections that were less known，including those among different disciplines and among scientists，indicating many different factors in the development of sciences. It is noted that the achievements winning this prize characterize the success of physics in understanding intelligence，and were initiative practice and triumph of statistical physics and emergentism. The future of physics will exist in various new forms. Related Articles | Metrics | Comments（0）

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Deep discussion about a mechanics problem of Chinese Physics Olympiad ZHOUZhi-wu1, LIUWen-biao1, 2 College Physics    2024, 43 (11): 16-.   DOI: 10.16854/j.cnki.1000-0712.240109 Abstract （881）      PDF（pc） （591KB）（402）       Knowledge map    Save Starting from a mechanics problem of Chinese Physics Olympiad, this paper delves into the motion of a slider on a smooth hemisphere under the influence of gravity. Beginning with a straightforward application of conservation laws to address the original query, this paper proceeds to derive the slider’s dynamic equations through force analysis using Newtonian mechanics. Furthermore, an analysis is carried out from the perspectives of Lagrangian and Hamiltonian mechanics, as well as the weak field approximation of general relativity, deriving dynamic equations consistent with those obtained via Newtonian mechanics. Numerical solutions are then employed to solve the dynamic equations, allowing for the visualization of the slider’s trajectory. Finally, a comparison is made between the trajectory of the slider’s motion on the smooth hemisphere under gravity and that on a vertical smooth conical surface. Related Articles | Metrics | Comments（0）

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Measurement of vortex beams topological charge based on  Michelson interferometric optical path LI Mo-xuan, WANG Yan-hao, XIE Xiao-na, ZENG Zi-meng, WANG Zhao-na College Physics    2024, 43 (12): 67-.   DOI: 10.16854/j.cnki.1000-0712.240100 Abstract （821）      PDF（pc） （656KB）（457）       Knowledge map    Save Vortex beams exhibit extremely important applications in optical communication, optical trapping, and other fields due to the orthogonal properties between the light fields with different topological charge numbers. In particular, the topological charge number is an important parameter for describing the phase distribution of vortex beams. Controlling and detecting this number is thus the basis for information loading and extraction in vortex beam communication. In this study, the petalshaped interference patterns are obtained and used to recover the phase distribution of vortex beams and detect the topological charge number of vortex beams based on the Michelson interference optical path. The measurement results are basically consistent with the theoretical results. Furthermore, considering the system error caused by the pixel scale of the spatial light modulator, the local phase and topological charge number are corrected. This method is also used to detect fractional topological charge and double topological charge for complex vortex beams. This work provides a feasible method for phase recovery and information extraction in complex optical light field. Related Articles | Metrics | Comments（0）

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Notes on the calculation of interplanar spacing using reciprocal lattice YANG Jun College Physics    2025, 44 (1): 23-.   DOI: 10.16854/j.cnki.1000-0712.240182 Abstract （776）      PDF（pc） （803KB）（335）       Knowledge map    Save Using the properties of reciprocal lattice，a general formula for calculating the crystal interplanar spacing is derived，which can be simplified when calculating the interplanar spacing of some crystals with special lattice constants. However，this formula cannot be directly used to calculate the interplanar spacing of complex unit cells. When the general formula derived from the reciprocal lattice properties is used to calculate the interplanar spacing of complex unit cells，either a representative crystal plane that meets the constraint conditions for the appearance of reciprocal points in that plane orientation should be considered，or the primitive cell corresponding to the complex unit cell should be found. Then，new basis vectors are constructed using the three edges of the primitive cell，and the basis vectors of the reciprocal lattice are obtained. Furthermore，the interplanar spacing of the original complex unit cell can be obtained by taking the reciprocal of the modulus length of the reciprocal basis vector with the same indices. Nevertheless，in the new basis vector system，the indices of the crystal planes marked in the original unit cell often change accordingly，which is often overlooked by students when calculating interplanar spacing，leading to incorrect results. In this paper，we first briefly describe the constraints for the appearance of reciprocal points on crystal planes of complex unit cell. Then，combining a specific example of a body-centered cubic unit cell，we present the process of calculating interplanar spacing using representative crystal planes or constructing new basis vectors，aiming to deepen students' understanding of these knowledge points through specific calculations and adopt them in practical applications. Related Articles | Metrics | Comments（0）

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Recurrence of Hertz experiment: measuring light speed using cellular wireless networks WANG Jingbo, ZHANG Sheng, HANG ZhiHong College Physics    2025, 44 (1): 101-.   DOI: 10.16854/j.cnki.1000-0712.240085 Abstract （775）      PDF（pc） （914KB）（190）       Knowledge map    Save Hertz successfully verified that electromagnetic waves and light have the same speed. This important experimental conclusion made electromagnetism and optics unified, and became the experimental basis of electrodynamics, which now is also one of the most important experiments in university physics. In this paper, a splitring resonator circuit under cellular wireless network is successfully designed and prepared. An accurate value of the speed of light as (3.007±0.018)×108 m/s is obtained by standing wave method, which is in good agreement with its actual value 2.998×108 m/s. In this experiment, only cellular phones and a splitring resonator circuit board (with circuit board design provided) are required, thus it can be carried out anywhere, where an identical observation method as Hertz's original experiment can be done. It may pave new road for relevant demonstrations for university and high school students. Related Articles | Metrics | Comments（0）

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Quantum Monte-Carlo simulation of one-dimensional harmonic oscillator LIU Peng-cheng1, FU Yu-jun1, SUN Jun-song1, ZHU Xing-chuan2, GUO Huai-Ming1 College Physics    2024, 43 (12): 53-.   DOI: 10.16854/j.cnki.1000-0712.240088 Abstract （760）      PDF（pc） （573KB）（190）       Knowledge map    Save A one-dimensional harmonic oscillator is an important model in quantum mechanics. This paper introduces a quantum Monte-Carlo simulation method to solve the harmonic oscillator problem. We derive the path integral formula for the partition function and use quantum Monte-Carlo methods to calculate physical quantities such as energy, position, momentum, position squared, and momentum squared of a one-dimensional harmonic oscillator at finite temperature. The results obtained are consistent with analytical solutions. This study aids students in deepening their understanding of quantum mechanics and serves as the foundation for quantum Monte-Carlo numerical simulations of the Holstein electronphonon model, thus facilitating related scientific research. Related Articles | Metrics | Comments（0）

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Notes on Retarded and Advanced Green's Function WANG Zi-hao, MENG De-shuo College Physics    2024, 43 (11): 78-.   DOI: 10.16854/j.cnki.1000-0712.230396 Abstract （759）      PDF（pc） （575KB）（233）       Knowledge map    Save  Based on the theory of complex variable function and the basic laws of electromagnetic phenomena, the Lorentz invariant form of the propagator function in quantum electrodynamics is studied first, and the relationship between the propagator function and the delayed and advanced Green function is discussed. Secondly, the delayed and advanced Green's functions are derived by Fourier transform and the properties of ordinary differential equations combined with the boundary conditions. The infinitesimal imaginary part is added to the wave number again and applied to the Fourier transform. The result is reproduced in a more rigorous and simple way by combining the residue theorem and the equivalent lemma. Finally, the specific expression of the Fourier-Laplace integral theorem is given. It provides a new idea for the teaching and research of electrodynamics. Related Articles | Metrics | Comments（0）

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Experimental method for measuring the top angle of a prism using the  double mirrors reflection method CHEN Baohua1, WU Quanying1, TANG Yunhai1, CHEN Gaoyuan1, WANG Jun1, SHEN Donghui2 College Physics    2025, 44 (2): 7-.   DOI: 10.16854/j.cnki.1000-0712.240261 Abstract （758）      PDF（pc） （815KB）（187）       Knowledge map    Save  In order to improve the complicated pose adjustment and operation steps involved in the experiment of measuring the top angle of the prism by spectrometer，optimize the structure space of the device and improve the measurement efficiency，a double-mirror reflection method is proposed. In this method，the laser as the light source is vertically incident on the bottom surface of the prism and refracted on the slope of the prism. The refracted light is reflected several times between the two parallel mirrors and received by the target surface of the CCD detector to form a laser spot，and the center position of the spot S1 is recorded. Rotate the prism by a known small angle β，at which time the light spot shifts，record the center position of the light spot after the shift S2，and calculate the displacement ΔS between S1 and S2. Finally，the angle β，the displacement ΔS and the measurement formula are used to calculate the top Angle a. The experimental results show that when the interval of two mirrors is between 65 mm and 95 mm，and the rotation Angle β is selected between 0.1° and 0.2°，the measurement error between the measured top Angle a of the prism to be measured and the standard value is less than 0.25%. This method doesnt involve complex telescope adjustment in the spectrometer. It not only folds the system optical path，reduces instrument weight，and optimizes device space，but also has high repeated measurement accuracy by using the double mirrors and an automatic reading program interface with a CCD camera. Related Articles | Metrics | Comments（0）

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Analysis of energy band structure of tightly  bound electrons in face-centered cubic lattice WANG Chang1, 2, HU Jianmin1, 2, LI Lin1, 2, GAO Feng1, 2, WANG Yueyuan1, 2 College Physics    2024, 43 (12): 15-.   DOI: 10.16854/j.cnki.1000-0712.240091 Abstract （749）      PDF（pc） （1040KB）（453）       Knowledge map    Save The tight-binding electron model is the key point in the teaching of band theory in solid state physics, while the band structure analysis of tight-binding electrons in face-centered cubic lattice is a teaching difficulty. In this article, a graphical method is proposed for analyzing the energy spectrum characteristics of tightly bound electrons in a face centered cubic lattice through numerical fitting. The results show that the energy spectrum varies in different directions and the energy band bottom is located in the center of simple Brillouin zone. The two high-energy extreme points are located at the four-face center and six-face center of the reduced Brillouin zone, respectively. The band widths along simple Brillouin zone center to four-faceted and six-faceted face-centered axes are 16-fold and 12-fold overlap integral, respectively. The relevant research results can not only provide an effective method for the analysis of crystal band structure, but also provide important theoretical guidance for the teaching of solid-state physics. Related Articles | Metrics | Comments（0）

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Solution of the stationary Schrödinger equation by the fast Fourier transform method College Physics    2024, 43 (11): 23-.   DOI: 10.16854/j.cnki.1000-0712.240117 Abstract （713）      PDF（pc） （796KB）（253）       Knowledge map    Save  The stationarySchrödinger equation is usually solved numerically using the finite difference method and shooting method in the coordinate space. This paper employs the Fourier transform to numerically solve the stationarySchrödinger equation in the momentum space, the solving speed is greatly improved by using the fast Fourier transform algorithm, and the corresponding MATLAB numerical codes were developed. By comparing with the analytic solutions of the eigenvalues and eigenfunctions of the one-dimensional harmonic oscillator, the reliability of the method and the correctness of the codes are verified, which provides an efficient numerical algorithm for solving the stationary Schrödinger equation. Related Articles | Metrics | Comments（0）

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Exploration of teaching skill training model of physics teacher education in  local university: a case study in Bohai university ZHOU Shu-jun, XIU Xiao-ming, WANG Chun-yan, LI Meng, WANG Long-sheng College Physics    2024, 43 (11): 54-.   DOI: 10.16854/j.cnki.1000-0712.240041 Abstract （685）      PDF（pc） （804KB）（311）       Knowledge map    Save  In this article, it is summarized that the ‘3211 teaching skill training model for physics teacher education has carried out in Bohai university based on years of practical experience in teaching and skill development. This training model is introduced from three aspects: main methods, innovations, and practical achievements. Taking the training process of 164 undergraduate students majoring in physics teacher education in 2019 class of the university as an example, the feasibility of this teaching skill training model for teacher trainees is explored, which can serve as a reference for the training of physics teacher trainees in other local universities． Related Articles | Metrics | Comments（0）

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Visualized analysis of ideological and political research of physics  curriculum in China based on CiteSpace YANG Yu-yan, LI Gui-an College Physics    2024, 43 (12): 37-.   DOI: 10.16854/j.cnki.1000-0712.240042 Abstract （665）      PDF（pc） （643KB）（239）       Knowledge map    Save  In recent years, the ideological and political teaching reform of physics course has become a hot topic in academic circles. Taking 690 documents in CNKI database as samples, with the help of the visual function of CiteSpace software, in this paper the number of papers, institutions and authors of ideological and political research on physics courses in China are analyzed. The research hotspots from the logical main line of 'why-what-how to do it' are also analyzed. Finally, the research in this field is summarized and the prospect is put forward: uniting educational efforts, promoting theoretical deepening, improving teachers' quality, improving teaching effectiveness and perfecting evaluation system. Related Articles | Metrics | Comments（0）

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reform under the guidance of new engineering JIANGChen-wei, FANG Ai-ping, ZHANG Er-hu, LIU Dan-dong, YU You-li, WANG Xing, ZHANG Yang, WANG Rui-min, LI Hong-rong, XU Zhong-feng, WANG Xiao-li College Physics    2024, 43 (11): 59-.   DOI: 10.16854/j.cnki.1000-0712.240098 Abstract （664）      PDF（pc） （968KB）（623）       Knowledge map    Save College physics course plays an irreplaceable and important role in the cultivation of new engineering talents．Driven by the demand for new engineering construction, Xi'an Jiaotong University has continued to promote the reform and innovation of college physics course teaching, and has achieved remarkable and fruitful results. In this paper, it is introduced the reform and innovation measures of Xi'an Jiaotong University in teaching concepts, models, contents, methods, means and evaluation under the educational concept of cultivating people with virtue, teaching and educating people, and quality is king, as well as the curriculum system with complete system, distinctive characteristics and excellent effects, and the teaching system of three basics, two comprehensives and one expansion in order to share the reform experience with peers and jointly make positive contributions to the national talent training work. Related Articles | Metrics | Comments（0）

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Exploration and practice on arousing students's intrinsic  motivation for learning LI Xiao-xin, QU Xiu-yun College Physics    2024, 43 (12): 41-.   DOI: 10.16854/j.cnki.1000-0712.240079 Abstract （661）      PDF（pc） （927KB）（287）       Knowledge map    Save  College physics lays an essential scientific foundation for students subsequent specialities and plays an irreplaceable role in cultivating their abilities. The student's initiative decisively impacts the effectiveness of their studies. It is observed that some students currently lack this learning initiative. Drawing from the concept of intrinsic motivation in psychology, a variety of strategies has been implemented to address this issue. These include effectively utilizing formative assessment to engage students, incorporating interesting content to grab students attention, following the cognitive law, structuring problems at different levels of complexity, and designing practical application scenarios with a focus on student development. By doing so, the aim is to arouse students intrinsic motivation, thereby to enhance their learning outcomes. Related Articles | Metrics | Comments（0）