• Title/Summary/Keyword: Physics

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Growth and Photocurrent Properties of $CuGaSe_2$ Single Crystal ($CuGaSe_2$ 단결정 박막 성장과 광전류 특성)

  • K.J. Hong
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2003.03a
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    • pp.81-81
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    • 2003
  • The stochiometric mixture of evaporating materials for the CuGaSe$_2$ single crystal thin films were prepared from horizontal furnace. Using extrapolation method of X-ray diffraction patterns for the polycrystal CuGaSe$_2$, it was found tetragonal structure whose lattice constant no and co were 5.615$\AA$ and 11.025$\AA$, respectively. To obtains the single crystal thin films, CuGaSe$_2$ mixed crystal was deposited on throughly etched GaAs(100) by the Hot Wall Epitaxy(HWE) system. The source and substrate temperature were 61$0^{\circ}C$ and 45$0^{\circ}C$ respectively, and the growth rate of the single crystal thin films was about 0.5${\mu}{\textrm}{m}$/h. The crystalline structure of single crystal thin films was investigated by the double crystal X-ray diffraction(DCXD). Hall effect on this sample was measured by the method of van der pauw and studied on carrier density and mobility depending on temperature. From Hall data, the mobility was likely to be decreased by pizoelectric scattering in the temperature range 30K to 150K and by polar optical scattering in the temperature range 150K to 293K. The optical energy gaps were found to be 1.68eV for CuGaSe$_2$ single crystal thin films at room temperature. The temperature dependence of the photocurrent peak energy is well explained by the Varshni equation then the constants in the Varshni equation are given by a=9.615$\times$ 10$^{-4}$ eV/K, and $\beta$=335K. From the photocurrent spectra by illumination of polarized light of the CuGaSe$_2$ single crystal thin films. We have found that values of spin orbit coupling ΔSo and crystal field splitting ΔCr was 0.0900eV and 0.2498eV, respectively. From the PL spectra at 20K, the peaks corresponding to free bound excitons and D-A pair and a broad emission band due to SA is identified. The binding energy of the free excitons are determined to be 0.0626eV and the dissipation energy of the acceptor-bound exciton and donor-bound exciton to be 0.0352eV, 0.0932eV, respectively.

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The Role of Tolerance to Promote the Improving the Quality of Training the Specialists in the Information Society

  • Oleksandr, Makarenko;Inna, Levenok;Valentyna, Shakhrai;Liudmyla, Koval;Tetiana, Tyulpa;Andrii, Shevchuk;Olena, Bida
    • International Journal of Computer Science & Network Security
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    • v.22 no.12
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    • pp.63-70
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    • 2022
  • The essence of the definition of "tolerance" is analyzed. Motivational, knowledge and behavioral criteria for tolerance of future teachers are highlighted. Indicators of the motivational criterion are the formation of value orientations, motivational orientation, and the development of empathy. Originality and productivity of thoughts and judgments, tact of dialogue, pedagogical ethics and tact are confirmed as indicators of the knowledge criterion. The behavioral criterion includes social activity as a life position, emotional and volitional endurance, and self-control of one's own position. The formation of tolerance is influenced by a number of factors: the social environment, the information society, existing stereotypes and ideas in society, the system of education and relationships between people, and the system of values. The main factors that contribute to the education of tolerance in future teachers are highlighted. Analyzing the structure of tolerance, it is necessary to distinguish the following functions of tolerance: - motivational (determines the composition and strength of motivation for social activity and behavior, promotes the development of life experience, because it allows the individual to accept other points of view and vision of the solution; - informational (understanding the situation, the personality of another person); - regulatory (tolerance has a close connection with the strong - willed qualities of a person: endurance, selfcontrol, self-regulation, which were formed in the process of Education); - adaptive (allows the individual to develop in the process of joint activity a positive, emotional, stable attitude to the activity itself, which the individual carries out, to the object and subject of joint relations). The implementation of pedagogical functions in the information society: educational, organizational, predictive, informational, communicative, controlling, etc. provides grounds to consider pedagogical tolerance as an integrative personal quality of a representative of any profession in the field of "person-person". The positions that should become conditions for the formation of tolerance of the future teacher in the information society are listed.

Development of Mass Proliferation Control Algorithm of Phytoplankton Using Artificial Neural Network (인공신경망을 이용한 식물플랑크톤의 대량 증식 제어 알고리즘 개발)

  • Seonghwa Park;Jonggu Kim;Minsun Kwon
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.29 no.5
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    • pp.435-444
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    • 2023
  • Suitable environmental conditions in Saemangeum frequently favor phytoplankton growth. There have been occurrences of sudden phytoplankton blooms, surpassing the algae management standards. A model was designed to prevent such blooms using scientific predictive techniques to forecast and regulate the possibility of phytoplankton blooms. We propose effective and efficient algae control measures concerning every phytoplankton species optimized through the policy control of nutrients (DIN, PO4-P) from rivers and controlling lake salinity using gate operations. The probability of phytoplankton blooms was initially forecast using an artificial neural network algorithm based on observations. The model's Kappa number fluctuated from 0.7889 to 1.0000, indicating good to excellent predictive power. The Garson algorithm was then utilized to assess the significance of explanatory variables for every species. Meanwhile, the probability of phytoplankton blooms was anticipated depending on the DIN and salinity value changes. Therefore, the model predicted the precise DIN and salinity concentrations to inhibit phytoplankton blooms for each species. Hence, the green algae model can create effective proactive measures to avoid future phytoplankton blooms in enormous artificial lakes.

Matter and Becoming in Gilbert Simondon's Theory of Individuation (물질과 생성: 질베르 시몽동의 개체화론을 중심으로)

  • Kim, Jaehee
    • Journal of Korean Philosophical Society
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    • no.93
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    • pp.231-260
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    • 2011
  • Simondon's theory of individuation and methodology of transduction presents a possibility of contemporary natural philosophy and a new perspective about the relation between philosophy and sciences. According to Simondon's anti-substantial viewpoint, being, as a metastable system charged with potential energy, complicates itself with quantum leaps transversing successive equilibriums. Individuation is the becoming of phases of being which transits from preindividual state to individuated states. Physical individuation as a paradigmatic model of individuation in general demonstrates not only insufficiency of form-oriented hylomorphism, but also spontaneous formational capacity of matter and reality of energetic relational operation immanent in matter. Genesis of a individual (structure or form) occurs as a resolution of the disparation between orders of magnitude, that is, the difference of potentials immanent in nature through the internal resonance, communication by information, transductive relation between the opposites. I'm trying to show that Simondon revives 'physis' of ancient natural philosophy by his own transductive applications of contemporary physics' conceptions, and therefore suggest a new non-reductive materialism. Especially Simondon's 'transduction' which is neither induction, deduction, nor dialectic, but an original ontological process and a peculiar method of thinking, I think, is worthy of note in order to construct network of knowledge and inter-relation between various sciences.

View of the God in Daesoon Thoughts viewed from Perennial Philosophy (영원의 철학(Perennial Philosophy)으로 본 대순사상의 신관)

  • Heo, Hoon
    • Journal of the Daesoon Academy of Sciences
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    • v.25_2
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    • pp.177-213
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    • 2015
  • We live in two giant pendulum in called 'science' and 'religion'. But science and religion are contained in disparate information with each other, Those two is not easy to achieve convergence. But if you accept the ontological scheme of Great Chain of Being(存在의 大連鎖) in the Perennial philosophy(永遠의 哲學), Debate between religion and science is meaningless 'Great Nest of Being(存在의 대둥지, Great Chain of Being)' is similar to the multiple concentric circles, there are different dimension that the each top level to subsume surrounding the lower level. For example, upper zone 'Mysticism(神秘主義)' includes but transcends(or transcends but includes.) the sub-region theology, psychology, biology and physics. The Perennial philosophy is the great spiritual teachers of the world, philosophers and thinkers have adopted a common worldview, a religious views. Philosophers of the perennial philosophy seem to match the cross-cultural almost unanimous about the general level of the 'Great Nest of Being' for the past 3,000 years. The perennial philosophy made the conclusion that God exists in the world. Several types of view of God existing religions in the world have 'Monotheism(一神論)', 'Pantheism(汎神論)' and 'Panentheism (汎在神論)'. Although traditionally the God of the philosophers is the classical Theism, theological trends of today it is moving in the direction of Panentheism. Panentheism see that god is immanent and transcendent. also Daesoon Thoughts is the position of the Panentheism. so this paper points out the fact that the view of God of the perennial philosophy is precisely consistent with the view of God of Daesoon Thoughts. Wilber says 'envelopment [transcend and include]'. The word translates as 'powol(包越)' in Korean. 'Powol(包越)' means that all the developmental evolution is to surround the sub-region developed into the higher realms. View of the God in the perennial philosophy is 'powol theism(包越的 有神論)'. but 'powol immanent God(包越的 內在神論)' rather than building regulations as 'powol theism(包越的 有神論)'. It would have to be a more accurate representation of it. Because in the existing 'theism(有神論)' the god and humans are thought to exist apart. However, Daesoon Thoughts are deemed to also recognize another universal laws. also Sangje(上帝, the Supreme God) is recognized as a cosmic existence that transcends the laws. This point, as the characteristics of the Daesoon Thoughts, In other religions can not be found. Therefore, More specifically represent(More accurately represent), Sangje of the Daesoon Thoughts can be described as 'powol theism' or 'transcendental and included deism(包越的 理神論)'. Importantly, The idea of God can be captured directly by the discipline. In this sense, In terms of the other religions have no discipline law, the practice [discipline] of the Daesoon Thoughts required in the present age. It has the absoluteness.

Nature of the Interfacial Regions in the Antiferromagnetically-coupled Fe/Si Multilayered Films

  • Moon, J.C.;Y.V. Kudryavtsev;J.Y.Rhee;Kim, K.W.;Lee, Y.P.
    • Proceedings of the Korean Vacuum Society Conference
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    • 2000.02a
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    • pp.174-174
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    • 2000
  • A strong antiferromagnetic coupling in Fe/Si multilayered films (MLF) had been recently discovered and much consideration has been given to whether the coupling in the Fe/Si MLF system has the same origin as the metal/metal MLF. Nevertheless, the nature of the interfacial ron silicide is still controversial. On one hand, a metal/ semiconductor structure was suggested with a narrow band-gap semiconducting $\varepsilon$-FeSi spacer that mediates the coupling. However, some features show that the nature of coupling can be well understood in terms of the conventional metal/metal multilayered system. It is well known that both magneto-optical (MO) and optical properties of a metal depend strongly on their electronic structure that is also correlated with the atomic and chemical ordering. In this study, the nature of the interfacial regions is the Fe/Si multilayers has been investigated by the experimental and computer-simulated MO and optical spectroscopies. The Fe/Si MLF were prepared by rf-sputtering onto glass substrates at room temperature with the number of repetition N=50. The thickness of Fe sublayer was fixed at 3.0nm while the Si sublayer thickness was varied from 1.0 to 2.0 nm. The topmost layer of all the Fe/Si MLF is Fe. In order to carry out the computer simulations, the information on the MO and optical parameters of the materials that may constitute a real multilayered structure should be known in advance. For this purpose, we also prepared Fe, Si, FeSi2 and FeSi samples. The structural characterization of Fe/Si MLF was performed by low- and high -angle x-ray diffraction with a Cu-K$\alpha$ radiation and by transmission electron microscopy. A bulk $\varepsilon$-FeSi was also investigated. The MO and optical properties were measured at room temperature in the 1.0-4.7 eV energy range. The theoretical simulations of MO and optical properties for the Fe/Si MLF were performed by solving exactly a multireflection problem using the scattering matrix approach assuming various stoichiometries of a nonmagnetic spacer separating the antiferromagnetically coupled Fe layers. The simulated spectra of a model structure of FeSi2 or $\varepsilon$-FeSi as the spacer turned out to fail in explaining the experimental spectra of the Fe/Si MLF in both intensity and shape. Thus, the decisive disagreement between experimental and simulated MO and optical properties ruled out the hypothesis of FeSi2 and $\varepsilon$-FeSi as the nonmagnetic spacer. By supposing the spontaneous formation of a metallic ζ-FeSi, a reasonable agreement between experimental and simulated MO and optical spectra was obtained.

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Analysis of Domestic and International Science Education Research Trends on Play: Focusing on Implications for Research in Elementary Science Education (놀이에 관한 국내·외 과학교육 연구 동향 분석 - 초등과학교육 연구를 위한 시사점을 중심으로 -)

  • Na, Jiyeon
    • Journal of Korean Elementary Science Education
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    • v.42 no.1
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    • pp.34-46
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    • 2023
  • To investigate the trends in science education research related to play and derive implications for elementary science education research, we analyzed 109 research articles on play in science education published both in Korea and abroad. First, the number of research studies conducted abroad has been steadily increasing since 2009, with the highest number targeting middle school students. Conversely, domestic research has the highest number of papers targeting elementary school students. Second, in terms of research methods, quantitative methods were the most commonly used. Third, the use of questionnaires was the most frequently published research method, while the use of observation and products was smaller in number in domestic studies compared to those conducted abroad. Fourth, In the aspects of the contents, more research was conducted in the field of physics than in other areas. In case of researches for elementary school students, domestic research was focused on four areas of science. Fifth, among the studies exploring effectiveness, the 'cognitive domain' was the most studied, followed by the 'science-related attitude domain' and the 'inquiry and practice domain'. Sixth, the use of play was high in the following order: online games, video games, virtual play, and games with rules. For domestic researches, studies on analog play were most frequently reported, and the ratio of digital games in abroad was higher than that of others. Seventh, the highest number of papers used teacher-directed play, and this tendency was more noticeable in domestic studies.

MD Simulation of PLA-PEG Composites for Additive Manufacturing (적층 가공에서 적용 가능한 PLA-PEG 복합재료의 MD Simulation)

  • Songhee Ham;Youngjoon Jeon
    • Applied Chemistry for Engineering
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    • v.34 no.3
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    • pp.285-290
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    • 2023
  • Poly-lactic acid (PLA) is the most promising polymer in additive manufacturing as an alternative to acrylonitrile butadiene styrene (ABS). Since it is produced from renewable resources such as corn starch and sugar beets, it is also biocompatible and biodegradable. However, PLA has a couple of issues that limit its use. First, it has a comparatively low glass transition temperature of around 60 ℃, such that it exhibits low thermal resistance. Second, PLA has low impact strength because it is brittle. Due to these problems, scientists have found methods to improve the crystallinity and ductility of PLA. Polyethylene glycol (PEG) is one of the most studied plasticizers for PLA to give it chain mobility. However, the blend of PLA and PEG becomes unstable, and phase separation occurs even at room temperature as PEG is self-crystallized. Thus, it is necessary to investigate the optimal mixing ratio of PLA-PEG at the molecular scale. In this study, molecular dynamics will be conducted with various ratios of L-type PLA (PLLA) or DL-type PLA-PEG (PDLA-PEG) systems by using BIOVIA Materials Studio.

Bird Tracks from the Cretaceous Sanbukdong Formation, Gunsan City, Jeollabuk-do, Korea (전라북도 군산시 산북동층에서 발견된 백악기 새 발자국 화석)

  • Dong-Gwon Jeong;Cheong-Bin Kim;Kyu-Seong Cho;Kyung Soo Kim
    • Journal of the Korean earth science society
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    • v.44 no.1
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    • pp.36-46
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    • 2023
  • In this study, small bird tracks from the Cretaceous Sanbukdong Formation in Gunsan City, South Korea, were briefly described. Detrital zircon SHRIMP U-Pb dating was conducted of the tuffaceous sandstone from the formation to determine the depositional age of the vertebrate track-bearing strata. Small bird tracks are not well-preserved but divided into two types: two consecutive tracks and three isolated tracks. They are small, asymmetric, slender, functionally-tridactyl tracks, which lack a web between digits. The consecutive and isolated tracks were identified as Koreanaornis dodsoni? and Koreanaornis ichnosp., respectively. This study adds avian tracks to the Sanbukdong tetrapod track assemblage composed of theropods, ornithopods, and pterosaur tracks. According to the U-Pb dating, the estimated age of the Sanbukdong Formation is 112.5±5.8 Ma, regard as the Aptian Stage, representing the maximum depositional age for the Sanbukdong Formation. The Sanbukdong Formation can be correlated with the lower part of the Jinju Formation in the Gyeongsang Basin. Thus, small avian tracks may represent the oldest Korean occurrence of Koreanaornis.

Analysis of public library book loan demand according to weather conditions using machine learning (머신러닝을 활용한 기상조건에 따른 공공도서관 도서대출 수요분석)

  • Oh, Min-Ki;Kim, Keun-Wook;Shin, Se-Young;Lee, Jin-Myeong;Jang, Won-Jun
    • Journal of Digital Convergence
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    • v.20 no.3
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    • pp.41-52
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    • 2022
  • Although domestic public libraries achieved quantitative growth based on the 1st and 2nd comprehensive library development plans, there were some qualitative shortcomings, and various studies have been conducted to improve them. Most of the preceding studies have limitations in that they are limited to social and economic factors and statistical analysis. Therefore, in this study, by applying the spatiotemporal concept to quantitatively calculate the decrease in public library loan demand due to rainfall and heatwave, by clustering areas with high demand for book loan due to weather changes and areas where it is not, factors inside and outside public libraries and After the combination, changes in public library loan demand according to weather changes were analyzed. As a result of the analysis, there was a difference in the decrease due to the weather for each public library, and it was found that there were some differences depending on the characteristics and spatial location of the public library. Also, when the temperature was over 35℃, the decrease in book loan demand increased significantly. As internal factors, the number of seats, the number of books, and area were derived. As external factors, the public library access ramp, cafe, reading room, floating population in their teens, and floating population of women in their 30s/40s were analyzed as important variables. The results of this analysis are judged to contribute to the establishment of policies to promote the use of public libraries in consideration of the weather in a specific season, and also suggested limitations of the study.