npsm 새물리 New Physics : Sae Mulli

pISSN 0374-4914 eISSN 2289-0041
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  • Research Paper 2022-06-30

    A Study on the Changes in the Physical Properties of MgxZn1-xO:In Thin Films Grown Using the Sol-gel Method according to the Precursor Concentration

    Hyo Jin Choi, Min Sang Lee, Hong Seung Kim et al.

    Abstract : In this paper, changes in physical properties of MgZnO:In thin films grown on a sapphire substrate using the sol-gel method were investigated as per the concentrations of In and Mg precursors. The properties of the grown thin films were analyzed using XRD, UV-Vis, Hall effect, and XPS. According to the XRD results, all samples showed the c-axis preferential orientation growth. UV-Vis analysis confirmed that the samples exhibited a transmittance of >80% in the visible region. Through the Hall effect measurement, the resistance was found to decrease with the increasing In amount. According to the XPS analysis, when >5 mol% of In was added, the Mg content decreased. The O 1s binding energy was also investigated using XPS, and the bonding state of the thin film was observed by comparing the OI/OII ratio. When >5 mol% of In was added, it interfered with the generation of oxygen vacancy during the synthesis of Mg, thus decreasing the OI/OII ratio.

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  • Research Paper 2022-06-30

    An Analysis of Student-generated Drawings in Terms of the Types of Scientific Explanations and Levels of Representations

    Jina Chang, Joonhyeong Park, Jisun Park

    Abstract : This study examined the features of student-generated drawings to foster their understanding of sound transmission. In this regard, eighteen student-generated drawings constructed by the fifth and sixth elementary science gifted students were collected and analyzed. The students were asked to draw and explain sound transmission between a tuning fork and our ears. The researchers classified the types of student-generated drawings by focusing on `air particles' and `their interactions', which are invisible, and key ideas of sound transmissions, and then analyzed the features of the students' conceptions, as visually expressed in each type. Consequently, most students focused only on the collisions among air particles, the medium transmitting sound, without conceptualizing the particle vibrations, i.e., the back-and-forth movements of particles. For example, some students drew that the particles themselves vibrate, or the particles literally transmit vibrations as if handing over an object. Finally, the educational implications were discussed in terms of alternative conceptions for elementary and middle school students and how to teach sound transmission.

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  • Research Paper 2022-05-31

    Effect of a Suppressing Additive on the Optical Reflectance of Electroplated Copper Surface

    Hoyoung Suh, Mina Heo, Kimin Hong

    Abstract : We have fabricated copper thin films by using an electroplating method. Specifically, we added an organic additive, Ralufon#14, in the plating electrolyte and observed the variation of the material property of the plated copper caused by Ralufon#14 in the electrolyte. By the addition of Ralufon#14 the crystalline orientation, grain size, and electrical resistivity changed significantly. In addition, compared to the thin films plated with pure electrolyte, the films prepared with Ralufon#14 exhibited considerable increase of the optical reflectance. The changes in crystalline orientation, grain size, and optical reflectance do not show noticeable variation when we increase the concentration of Ralufon#14 in the electrolytes.

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  • Research Paper 2022-05-31

    A Study on the Temperature Dependence of Exchange Bias on the Planar Hall Effect of NiFe/IrMn Bilayer

    Eui Young Choi, Ji Ho Kim, Ji Won Seo et al.

    Abstract : We analyzed the correlation between the planar Hall effect and the exchange bias according to the temperature in the NiFe/IrMn layered structure. As a result, it was confirmed that the temperature dependence of the exchange bias caused by the spin structure of IrMn determines the sensor sensitivity of the planar Hall effect. Above the critical temperature, the magnetic anisotropic property decreases as the temperature increases owing to thermal fluctuation; accordingly, the sensor sensitivity of the planar Hall effect decreases. By contrast, at low temperatures near 3 K, the exchange bias rapidly increases owing to the spin glass phenomenon caused by IrMn; thus, the sensor sensitivity of the planar Hall effect rapidly decreases. Our fundamental research on exchange bias, an important factor in determining the sensitivity of planar Hall sensors, is expected to help design more capable planar Hall sensors.

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  • Research Paper 2022-04-29

    Search for New Physics Using High Energy Collider Data

    Myeonghun Park*

    Abstract : New Physics searches using a high energy collider experiment should be performed systematically, especially when interpreting a new signal with a specific new Physics model among different possibilities. A data-driven method should be used in a model-independent way to capture all scenarios. In this article, we demonstrate how one can achieve a systematic and model-independent data analysis by separating an analysis on a new Physics signature into a phase space structure and matrix amplitude of a process. For instance, we consider a process with two visible particles and dark matter candidate signal at the high energy hadron collider. Finally, we recommend a proposed method to combine with a machine learning network and an algorithm to probe the broad scope of Physics beyond the standard model efficiently.

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Current Issue

    June, 2022 | Volume 72, No. 6
  • Research Paper 2022-06-30

    A Study on the Changes in the Physical Properties of MgxZn1-xO:In Thin Films Grown Using the Sol-gel Method according to the Precursor Concentration

    Hyo Jin Choi, Min Sang Lee, Hong Seung Kim et al.

    Abstract : In this paper, changes in physical properties of MgZnO:In thin films grown on a sapphire substrate using the sol-gel method were investigated as per the concentrations of In and Mg precursors. The properties of the grown thin films were analyzed using XRD, UV-Vis, Hall effect, and XPS. According to the XRD results, all samples showed the c-axis preferential orientation growth. UV-Vis analysis confirmed that the samples exhibited a transmittance of >80% in the visible region. Through the Hall effect measurement, the resistance was found to decrease with the increasing In amount. According to the XPS analysis, when >5 mol% of In was added, the Mg content decreased. The O 1s binding energy was also investigated using XPS, and the bonding state of the thin film was observed by comparing the OI/OII ratio. When >5 mol% of In was added, it interfered with the generation of oxygen vacancy during the synthesis of Mg, thus decreasing the OI/OII ratio.

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  • Research Paper 2022-06-30

    Characterization of a 20-inch Micro Channel Plate Photomultiplier Tube

    Geonwoo Kim, Jik Lee, Hongjoo Kim*

    Abstract : There is a proposal to construct a large neutrino detector in Korea, called Korean Neutrino Observatory (KNO), which consists of a large water tank and several tens of thousands of photosensors placed deep underground for neutrino detection. A 20-inch-diameter photosensor including a microchannel plate-photomultiplier Tube (MCP-PMT) is a candidate for the KNO due to its large photo-coverage. We characterized a 20-inch MCP-PMT by measuring its properties, including single photoelectron charge resolution, gain, signal-to-noise performance, dark count rate, after-pulse ratio, and timing performance. We present our measurements of its properties and compare them with those of a previous study.

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  • Research Paper 2022-06-30

    Analysis of Peer Instruction Activities in the Preservice Science Teachers' Inquiry Planning

    Bongwoo Lee*

    Abstract : The purpose of this study is to analyze the characteristics of peer instruction activities in the preservice science teachers’ inquiry planning. The preservice teachers formulated their inquiry plans and presented opinions regarding the improvement of the inquiry plans of other groups. Later, they modified their own inquiries considering of these opinions. The main findings are as follows: first, the most offered opinions from the preservice teachers in terms of peer instruction were related to the `hypothesis generation and experiment design' phase. Among them, several opinions were related to variables, especially those proposing ways to add or modify independent variables. Second, they offered numerous opinions `suggesting something else'. They offered multiple opinions suggesting different subjects or materials and different experimental devices. Preservice teachers used scientific communication that provided a logical basis for determining whether to reflect upon the opinions proposed by others. They also showed a positive side of mutual cooperation by actively participating in the improvement of other groups’ inquiries.

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  • Research Paper 2022-06-30

    An Analysis of Student-generated Drawings in Terms of the Types of Scientific Explanations and Levels of Representations

    Jina Chang, Joonhyeong Park, Jisun Park

    Abstract : This study examined the features of student-generated drawings to foster their understanding of sound transmission. In this regard, eighteen student-generated drawings constructed by the fifth and sixth elementary science gifted students were collected and analyzed. The students were asked to draw and explain sound transmission between a tuning fork and our ears. The researchers classified the types of student-generated drawings by focusing on `air particles' and `their interactions', which are invisible, and key ideas of sound transmissions, and then analyzed the features of the students' conceptions, as visually expressed in each type. Consequently, most students focused only on the collisions among air particles, the medium transmitting sound, without conceptualizing the particle vibrations, i.e., the back-and-forth movements of particles. For example, some students drew that the particles themselves vibrate, or the particles literally transmit vibrations as if handing over an object. Finally, the educational implications were discussed in terms of alternative conceptions for elementary and middle school students and how to teach sound transmission.

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  • Research Paper 2022-06-30

    Determination of Nonlinear Refraction and Absorption Coefficient of MO/PVA film Using a Radially Varying Aperture Scan Method

    Gun Yeup Kim*, Chong Hoon Kwak

    Abstract : We proposed a radially varying aperture scan (RVA scan), which simultaneously determines both the magnitudes of nonlinear refraction and absorption coefficient and their signs. Additionally, we experimentally obtained the nonlinear optical coefficients such as effective nonlinear refractive index γeff and effective nonlinear absorption coefficient βeff against various concentrations of MO (Methyl Orange) azo-dye embedded in PVA (Polyvinyl Alcohol) polymer film. Comparing the experimental data with the proposed RVA scan theory, we estimated the nonlinear optical coefficients of the MO/PVA film, showing excellent agreements with the theory. To validate of the RVA theory, we compared the effective nonlinear coefficients, measured by two independent RVA scan and conventional Z-scan for the fabricated MO/PVA film, which showed excellent agreements.

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  • Research Paper 2022-06-30

    Optical Design and Light-emitting Effect Analysis to Improve the Uniform Light Distribution Characteristics of Large-area Flat-type LED Lighting Systems

    So Hee Park*

    Abstract : As the technology of fusion lighting develops rapidly, the reliable technology of lighting systems along with more differentiated display technology must be a research focus. In this study, to improve the light distribution characteristics of a large-area flat-type lighting system and to prepare a way to maximize the light efficiency, the light-emitting effect based on the change in the etching shape of the light incident part of LGP was analyzed. As a result, when the light incident part was etched in a curved shape, the illuminance was 407 Lux, which increased by 63% compared to when it was not etched. Moreover, compared to the light guide plate etched in a rectangular shape, it was improved by 53%. The optical design condition of the light incident part is also an important factor because when the light concentrated on the light incident part is evenly incident into the light guide plate, the glare can be minimized with uniform light distribution characteristics. Therefore, it was confirmed that the appropriate application of the etching type of the light incident part can also be a factor in measuring the efficiency of a large-area flat-type lighting system.

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Current Issue

June, 2022
Vol.72 No.6

pISSN 0374-4914
eISSN 2289-0041

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