Ex) Article Title, Author, Keywords
pISSN 0374-4914
eISSN 2289-0041
pISSN 0374-4914
eISSN 2289-0041
Ex) Article Title, Author, Keywords
Abstract : This study introduces a scientific inquiry activity to analyze the magnetic braking phenomenon. This phenomenon occurs when a permanent magnet is brought close to a rotating conductive plate, resulting in a decrease in the plate’s velocity due to magnetic drag force (FD). The FD was measured using the rotated angles of a permanent magnet pendulum positioned near the conductive plate while the plate was rotating. This FD demonstrated a linear proportionality to the velocity. The coefficient α, determined by the electrical resistances inside and outside the magnetic field zone on the plate, exhibits a dependence on the magnet’s shape and is proportional to the square of distance (d) between the magnet and the plate. This proportionality arises because the area of the magnetic field (B) on the plate increases with increasing d. The area coefficient, χ, was determined by this relationship. When the circular or square magnet is positioned near the rotating conductive plate, the FD exponentially decreases the plate’s angular velocity (ω). The inverse of the time constant, 1/τ, is linearly proportional to χB2.
Abstract : Atomic force microscopy (AFM) is widely used for surface analysis due to its versatility and ability to provide 3D surface information. Especially, the quartz tuning fork (QTF)-AFM enables highly sensitive measurements with a simple electronic circuit, while scanning electron microscopy (SEM) allows rapid high-resolution imaging over large areas. To combine the strengths of these two techniques, a hybrid system integrating QTF-AFM and SEM was developed to analyze how the QTF, a key component, responds in a vacuum environment depending on the presence of the probe under vacuum and electron beam exposure. As a results, in a vacuum environment, it was observed that the QTF’s quality factor (Q) increased when transitioning from atmospheric pressure to vacuum, and the amplitude of the resonant frequency slightly decreased but stabilized over time with minimal phase change.
Abstract : The purpose of this study is to analyze the inquiry process of science-gifted students using classical methods in relation to Galileo's inclined plane experiment and to assess their perception of classical experimental methods. The gifted students designed and conducted experiments using both classical methods, simulating the 17th-century context, and modern methods, utilizing video analysis techniques. The main research findings are as follows. First, the gifted students designed and conducted experiments using the classical method with time and travel distance as the main variables, employing pendulums, water clocks, constant velocity motion devices, and hourglasses as time measurement tools. Second, despite the presence of error factors due to uncertainty in human sensory perception or the limitations of measurement tools in the classical method, the experimental results are very successful. Third, many gifted students exhibited a positive shift in their perception of classical methods after the activity. Based on the findings of this study, the potential for integrating classical methods with modern methods is discussed.
Abstract : The electromagnets used in the 4th Generation electron Storage Ring (4GSR) require a higher field gradient than the conventional magnets facilitated in a machine. However, the magnetic field at the pole-tip saturates at the level of 1.3 T, resulting in the dilution of the operational efficiency. Therefore, a higher magnetic field gradient is only feasible by reducing the diameter of the magnet. However, as the diameter of the magnet decreases, the shape of the pole determines the higher-order term strongly, so it is essential to take account into the design of the magnet. In this presentation, we present an optimization strategy of the pole shape for the occasion of magnetic saturation using a 2D solver and Pymoo optimization algorithms using the Poisson Superfish code.
Abstract : As an essential feature of doing science or physics, inquiry and laboratory work have been emphasized as both pedagogical goals and strategies. The discussion on what constitutes physics inquiry and laboratory work has philosophical, cultural and historical aspects and also reflects the relatively recent development of science curriculum. In this paper, I have reviewed how the notion of science inquiry and laboratory work has changed and elaborated on the recent emphasis on scientific practices in doing physics. The review has shown that students’ doing science or physics entails their epistemic agency while participating in scientific practices and sensemaking. Following the review, I have presented an empirical analysis of middle school science teachers’ facilitation, or lack thereof, of students’ sensemaking during scientific practices. The analysis revealed several strategies that facilitated students' sensemaking during scientific practices and underscored the critical role of teacher noticing in supporting students’ sensemaking. Further research topics are suggested in the conclusion.
Abstract : PEDOT:Sulf-NMP films using sulfuric acid (H2SO4) with various concentrations as a dopant were prepared and analyzed to improve the electrical properties of conductive polymer poly(3,4- ethylenedioxythiophene) (PEDOT). These films were fabricated by doping PEDOT:OTf-NMP films with sulfuric acid concentrations ranging from 0.1 M to 18.4 M, followed by measurements of conductivity, oxidation level and surface property. As sulfuric acid concentration increases, the oxidation level and crystallinity of the PEDOT:Sulf-NMP films were significantly improved, and the surface domain boundaries were most clearly observed, particularly at a concentration of 1.0 M. Although the films treated with high-concentration sulfuric acid show elevated oxidation levels, the resulting increase in conductivity was limited due to increased non-crystallinity. These findings indicate that the conductivity of PEDOT films can be controlled by adjusting the doping concentration, suggesting potential applications such as transparent electrodes and thermoelectric devices.
Abstract : Interface control plays a pivotal role in optimizing charge carrier injection in organic optoelectronic devices. Despite the universal use of 1,4,5,8,9,12-hexaazatriphenylene-2,3,6,7,10,11- hexacarbonitrile (HAT-CN) layers in such devices, their conduction mechanisms remain unclear. In this work, electrical measurements and ultraviolet photoelectron spectroscopy reveal that a 3 nm-thick HAT-CN hole injection layer enables direct tunneling conduction to the N,N’-bis(1- naphthyl)-(1,1’-biphenyl)-4,4’-diamine (NPB) hole transport layer, fundamentally challenging the conventional charge-generation mechanism that relies on thermal energy. Furthermore, these findings highlight that the unique electronic properties of HAT-CN layers provide valuable insights into the charge injection mechanisms, paving the way for the optimization of next-generation organic optoelectronic devices.
Abstract : The Landau-Khalatnikov(LK) simulation was used to study the coupling between ferroelectric and ferroelastic properties in perovskite ferroelectric BaTiO3. The coupling term was added with coupling parameter γ, between polarization(P) and strain(μ) of γP2μ2 in free energy density functional for LK simulation. By changing the external electric field(E) or stress(σ), piezoelectric μ − E and P − σ loops were simulated together with P − E and μ − σ loops. The derivative of μ−E loop showed E dependent piezoelectric coefficient behavior similarly to the piezoelectric force microscope response. This result showed that LK simulation is applicable to piezoelectric responses.
Abstract : We introduce a novel dichroic coating method that utilizes the unique optical properties of organic dyes to achieve selective reflection and transmission depending on the wavelength. The large transition dipole moment of organic materials leads to strong absorption at specific wavelengths, along with abrupt changes in the nearby permittivity. In highly absorbing organic dyes, there exists a wavelength range where the real part of the permittivity becomes negative, allowing the material to optically behave like a metal and exhibit high reflectivity in that range. By exploiting this property, we designed dichroic coating films that reflect only specific wavelength ranges while transmitting others. Using the finite-difference time-domain (FDTD) method, we confirmed that the dichroic property is maintained across various thicknesses and incident angles, followed by the experimental realization of the organic dye thin films using solvent processing. The optical characteristics of the fabricated films, including reflection and transmission, were evaluated using UV-VIS-NIR spectroscopy.
Abstract : In this research, a simulation was performed to verify the effectiveness of using a photomultiplier tube (PMT) to measure the decay time of a liquid scintillator. When a radioactive particle interacts with the liquid scintillator, it produces scintillation light, which can be analyzed by examining its decay time characteristics. However, when observing scintillation through a PMT, the signal is often distorted due to various factors. This study developed a simulation to model such distortions and assessed whether the decay time could still be accurately measured using the PMT by fitting the distorted signal and comparing it to the input decay constant. The simulation results demonstrated that fitting the waveform in a region sufficiently distant from the peak produced values consistent with the input decay constant. This confirms the feasibility of using a PMT to accurately measure the decay time of liquid scintillators.
Abstract : This study introduces a scientific inquiry activity to analyze the magnetic braking phenomenon. This phenomenon occurs when a permanent magnet is brought close to a rotating conductive plate, resulting in a decrease in the plate’s velocity due to magnetic drag force (FD). The FD was measured using the rotated angles of a permanent magnet pendulum positioned near the conductive plate while the plate was rotating. This FD demonstrated a linear proportionality to the velocity. The coefficient α, determined by the electrical resistances inside and outside the magnetic field zone on the plate, exhibits a dependence on the magnet’s shape and is proportional to the square of distance (d) between the magnet and the plate. This proportionality arises because the area of the magnetic field (B) on the plate increases with increasing d. The area coefficient, χ, was determined by this relationship. When the circular or square magnet is positioned near the rotating conductive plate, the FD exponentially decreases the plate’s angular velocity (ω). The inverse of the time constant, 1/τ, is linearly proportional to χB2.
Abstract : This study explored the conceptual understanding of light among 16 middle school students at a school for the visually impaired. A survey with one descriptive and eight multiple-choice items was developed based on previous studies and administered using a teacher’s voice support and enlarged text. The understanding of light was analyzed in two categories and seven subtopics: substance of light, vision, light propagation, shadow, reflection, refraction, and color. The results showed that the conceptual understanding of blind students in the category of the nature of light was similar to or better than that of sighted students in terms of scientific conceptual understanding. The types of misconceptions exhibited by blind students were similar to those of sighted students and were independent of the degree of visual impairment, such as total blindness or low vision. In the interaction of light with matter category, the proportion of scientific concept understanding in the topics of shadow and reflection was higher for the total blindness than for the low vision, and the low vision students had similar misconceptions as the sighted students.
Abstract : This study aims to measure the angular distance of the shadow zone using an experimental model of the shadow zone based on the refraction of light, and estimate the refractive index of the outer core based on this. The relationship between the minimum angle of divergence of a triangular prism and the angular distance of the shadow zone is established through experiments and simulations, and the refractive index is measured using the optical refraction relationship. Based on the idea from the existing prism optics theory, the refractive index relationship is verified through experiments and simulation data. In addition, the relationship between the angular distance of the shadow zone and the minimum angle of divergence is clarified by using the fact that the path of light constituting the minimum angle of divergence reaches the end of the shadow zone. Ultimately, the key goal of this study is to accurately derive the refractive index of the outer core using the angular distance of the end of the shadow zone. This study can be used as an important educational tool to explain the formation and refraction phenomenon of the shadow zone in earth science and physics education, and provides a new experimental approach that applies optics to physics and earth science education.
Abstract : The purpose of this study is to analyze literature using smartphone sensors to investigate physical phenomena. Through an international academic database, 86 pieces of literature were extracted until December 2023, and analyzed by year, country, branches, and sensors used, among other factors. The study finds that smartphone-related literature started in 2012, maintained a steady volume of publications, and peaked in 2020. The primary area of exploration is classical mechanics, and the most commonly used sensors are those for acceleration, light, and sound, while the use of electrical and barometric sensors is relatively low. More than half of the literature is authored by researchers from Germany, the USA, Italy, and Turkey, predominantly targeting university students rather than middle or high school students. Through the systematic literature review conducted in this study, suggestions were made regarding the necessity of providing various teaching-learning examples utilizing smartphone sensors in school settings, addressing areas for improvement, and emphasizing the need for further research on their educational effects.
Abstract : In this study, we solved the eigenfunction and eigenvalue problems of the Schrödinger equation with a Gaussian potential, which plays an important role in both theoretical and experimental contexts, using Physics-Informed Neural Networks (PINNs). Since the Gaussian potential lacks an analytical solution, we validated the results obtained from PINNs using the finite difference method. The results showed that PINNs closely matched the finite difference method for the ground state and lower energy levels, with eigenvalues agreeing within a 1% margin of error. However, at higher energy levels, discrepancies arose due to boundary conditions and the limitations of the orthogonality loss function. This study demonstrates the potential of applying PINNs to eigenvalue problems in realistic experimental scenarios and discusses their possible use in future research on complex quantum systems and as an educational tool.
Abstract : Atomic force microscopy (AFM) is widely used for surface analysis due to its versatility and ability to provide 3D surface information. Especially, the quartz tuning fork (QTF)-AFM enables highly sensitive measurements with a simple electronic circuit, while scanning electron microscopy (SEM) allows rapid high-resolution imaging over large areas. To combine the strengths of these two techniques, a hybrid system integrating QTF-AFM and SEM was developed to analyze how the QTF, a key component, responds in a vacuum environment depending on the presence of the probe under vacuum and electron beam exposure. As a results, in a vacuum environment, it was observed that the QTF’s quality factor (Q) increased when transitioning from atmospheric pressure to vacuum, and the amplitude of the resonant frequency slightly decreased but stabilized over time with minimal phase change.
Abstract : In non-destructive testing using high-energy radiation, the detection of cracks varies depending on the performance of the image acquisition system. Since high energy is used, the penetration is strong, so the degree measured by the detector varies, and the design of the image acquisition system is required. In general, a scintillator with excellent density is used to detect high-energy radiation, and detector using a GOS is mainly used. Existing non-destructive testing detectors on the market use a GOS with a thickness of about 1 mm, and a photodiode is used as the light sensor. A GOS with a low thickness is not enough to sufficiently detect high-energy radiation. In this study, a detector with excellent density and different thicknesses and types of scintillators was designed to apply the image acquisition system. The performance of the designed system was evaluated through a comparative evaluation with the detector used in the past. As a result, it was confirmed that the size of the measurable cracks varied by changing the thickness of the scintillator used. The possibility of designing an excellent image acquisition system was confirmed by applying various types and thicknesses of scintillators in the detection system.
Youngchun Jo, Haeyong Kang, Hyunkyung Lee, Jinho Jeon, Hyeonseop Lee, Kanghyun Kim
New Phys.: Sae Mulli 2024; 74(1): 25-34
https://doi.org/10.3938/NPSM.74.25
Sangwoo Ha
New Phys.: Sae Mulli 2023; 73(9): 734-749
https://doi.org/10.3938/NPSM.73.734
Hunkoog Jho*
New Phys.: Sae Mulli 2024; 74(8): 812-823
https://doi.org/10.3938/NPSM.74.812
pISSN 0374-4914
