In current college physics textbooks, the way of teaching the damped harmonic oscillation brings a certain cognitive load to students who lack a background in differential equation theory. Taking General Physics for undergraduates majoring in physics as an example, its modern teaching method has already reduced certain mathematical requirements through deductive reasoning. However, the exotic solution of critical damping problem makes it impossible to integrate into the teaching process naturally. In this paper, a new derivation method for solving the critical damping by using the limit method and its corresponding teaching methods is presented. This innovative solution process and teaching methodology not only help to cultivate the scientific thinking and innovation ability of physics undergraduates, but also can be used as supplementary material to expand the teaching of the damped harmonic oscillation for non-physics science and engineering students. 

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.

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.

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.

Based on the eigenvalues and eigenfunctions of the angular Mathieu function, we disscusse the energy differences and relationships among the inclined quantum pendulum, harmonic oscillator and plane rotor. The probability density distribution influenced by energy levels, inclination angles and dimensionless parameter U0 are also analyzed. The lower energy level of quantum pendulum is non-degenerate, but the degeneracy of the quantum pendulum at higher excited state is two. Although the quantum pendulum energy at lower energy level is close to that of the harmonic oscillator, the probability density distribution generally exceeds that of the classical pendulum. Several factors affect the probability density distribution of inclined quantum pendulum.

The condensation of nanoparticles, the holes of porous materials, and the morphology of quasi-crystals are difficult to describe the teaching of solid state physics. Therefore，the experiment on the fractal structure is introduced into the process of teaching for the visual presentation. Based on a simple experiment on finger fractal, the fractal structures and dimensions that a mixture of ink and alcohol on the diluted acrylic paint are investigated. By changing the ratio of ink and alcohol in mixture and concentration of acrylic paint, the factors affecting the fractal structure of fingers are obtained, including the applied electric field and temperature, which is helpful for students to understand the fractal theory. Lastly, the growth of dendritic crystal is simulated based on COMSOL software, which shows that the fractal structure is related to anisotropy and dimensionless latent heat. The introduction of interesting experiment, will be help for cultivating students' innovation awareness and self-investigation ability, which is an important link of practice teaching under the background of new engineering.

With increasing aperture of optical telescopes and the continuous development of new technologies, many important advances have been made in modern astronomy. In addition, a good site is also of great significance for astronomical ground observation. In this paper, some key technologies of optical telescope are discussed, such as optical splicing technology, adaptive optics technology and so on. At the same time, the existing optical sites and representative telescopes in China are summarized.

 In contemporary research within physics and materials science, smart materials play a crucial role. Magnetic fluids, characterized by high magnetization, low viscosity, and longterm stability, are a type of smart material with significant industrial applications. This paper specifically explores the mechanism behind the formation of magnetic chain structures in magnetic fluids and their impact on the properties of these fluids. The study reveals that the formation of magnetic chain structures not only affects the magnetic and rheological properties of magnetic fluids but also has a crucial impact on their applications in magnetic fluid sealing, damping, and sensors. The research conducted in this paper serves as a reference for a deeper understanding of the mechanism and properties of magnetic chain structures in magnetic fluids. Future studies could further investigate the applications of magnetic chain structures and explore methods to mitigate inconveniences associated with chainlike structures, thereby expanding their applications across different domains.

 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.

 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.

Students as nongovernmentfunded pedagogical students are subordinate to pedagogical students while they shall not enjoy privileges belonging to governmentfunded ones. As a result, their appeals which should have been paid attention to are now becoming stronger with the population increasing. The conclusion shows that the nongovernmentfunded pedagogical students’ academic performance is significantly greater than governmentfunded ones. Their academic motivation mainly arouses from inner motivation. Their academic stress mainly arouses from competition in curricula. Their academic planning is influenced by both inner and outer factors. Suggestions concerning students, administrators, and policy are put forward based on the analysis of causes.

In order to fully implement national quality standards and excellent teacher training plan, and follow the development needs of employers and students, a curriculum system with professional concepts and ethics, professional knowledge and professional ability as the basic content is formed in the physics major of Nantong University. By adopted the UGS joint practice system，the government, universities and local middle schools cooperate to educate students. This kind of joint training mode pays more attention to the sinking and connection of the basic concepts and basic laws of middle school physics, so as to realize the deep understanding and integration of students' subject knowledge and normal university students' skills. In this paper, it is also introduced how to expand the teaching space of normal university students with the help of caseteaching and realize the sharing of highquality teaching resources.

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.

Laser holographic imaging experiment is an important part of modern physics experiment in university. By using the principle of light interference, the object light and reference light which meet the coherent conditions are recorded on the dry holographic plate in the form of interference fringes to form a hologram. The amplitude and phase information of the light wave reflected by the object can be recorded to form a threedimensional and vivid threedimensional holograms image. Due to the high complexity of the experiment, the imaging effect is often affected by many factors and it leads to a high failure rate of the experiment. In this paper, the effects of the intensity ratio and the optical path difference of object light to reference light and the parameter characteristics of the light source on the imaging results are analyzed. At the same time, a new method to obtain the interference fringes under the same conditions by designing optical path is proposed so that the results of holographic imaging can be described quantitatively. Finally, the optimal parameters of imaging are obtained, which provided a good reference for the improvement of experimental success rate and imaging effect.

The colorful lines on the back of disc are well known, but the physics behind them are rarely explored. Starting from the special phenomena observed in daily life, in this paper experiments are designed to systematically study the characteristics of color lines and stripes behind disc and to find out the fringe bending phenomenon that is different from the traditional empirical law. Creatively, the theory of OPDfield is proposed to explain it in combination with the unique structural characteristics of disc. Then it is verified quantitatively by Matlab simulation and experiment. Finally, the concept of traditional grating is enriched from the symmetry point of view and the physical connotation behind the empirical law of grating diffraction is revealed, which provides a new way to study the spectral effect of grating diffraction and enriches the teaching content．

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.

This article introduces a simple method of locating the centroid of the stick-like object. By supporting the object with two fingers at each end and slowly moving them towards each other, the position of the centroid will be revealed under the works of supporting and frictional forces. The article starts with the ideal model abstracted from a pen and presents additional analysis of the physical principle in the progress. Through semi-quantitative experiments, compared with some traditional methods to find the centroid, this article illustrates the advantages and disadvantages of the new method. The principle of this method has certain application value in teaching, popularization of science, life and production.

(Inner Mongolia University for Nationalities, School of Physics and Electronic Information, Tongliao,Inner Mongolia 028000, China)

Abstract:In this paper, the relation between the additional pressure on the axis and the moment of inertia of a rigid body rotating on a fixed axis is discussed. Based on the vertical axis theorem of moment of inertia, the additional pressure of different mass distribution and thickness of disk is analyzed, and the influence of mass distribution and thickness of disk on the additional pressure is discussed. The theoretical analysis shows that there is a close quantitative relationship between the mass distribution and thickness of the disk and the additional pressure, which is of great significance for engineering design and theoretical research of physics.
Key words:moment of inertia; vertical axis theorem; additional pressure on the shaft