• Korean Journal of Optics and Photonics
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• v.30 no.2
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• pp.37-47
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• 2019

A reflecting omnidirectional optical system with four spherical and aspherical mirrors, for use with long-wavelength infrared light (LWIR) for night surveillance, is proposed. It is designed to include a collecting pseudo-Cassegrain reflector and an imaging inverse pseudo-Cassegrain reflector, and the design process and performance analysis is reported in detail. The half-field of view (HFOV) and F-number of this optical system are $40-110^{\circ}$ and 1.56, respectively. To use the LWIR imaging, the size of the image must be similar to that of the microbolometer sensor for LWIR. As a result, the size of the image must be $5.9mm{\times}5.9mm$ if possible. The image size ratio for an HFOV range of $40^{\circ}$ to $110^{\circ}$ after optimizing the design is 48.86%. At a spatial frequency of 20 lp/mm when the HFOV is $110^{\circ}$, the modulation transfer function (MTF) for LWIR is 0.381. Additionally, the cumulative probability of tolerance for the LWIR at a spatial frequency of 20 lp/mm is 99.75%. As a result of athermalization analysis in the temperature range of $-32^{\circ}C$ to $+55^{\circ}C$, we find that the secondary mirror of the inverse pseudo-Cassegrain reflector can function as a compensator, to alleviate MTF degradation with rising temperature.

• Journal of the Korea Organic Resources Recycling Association
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• v.30 no.3
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• pp.5-12
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• 2022

This study suggests the effective recycling method of sludge waste from various industrial fields to synthesize uniform colloidal silica nanoparticles. In detail, polymers are removed from the sludge waste to attain sludge-extracted silica (s-SiO₂) micron-sized particles, and ammonia assisted sonication is applied to s-SiO₂, which has effectively extracted the silanol precursor. The nano-sized silica (n-SiO₂) particles are successfully synthesized by a typical sol-gel method using silanol precursor. Also, the yield amounts of n-SiO₂ are determined by the function of s-SiO₂ etching time. Finally, n-SiO₂-based slurry is synthesized for the practical CMP application. As a result, rough-surfaced semiconductor chip is successfully polished by the n-SiO₂-based slurry to exhibit the mirror-like clean surface. In this regard, sludge wastes are successfully prepared as valuable semicondutor grade materials.

• Journal of Software Assessment and Valuation
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• v.16 no.2
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• pp.117-125
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• 2020

In this paper, when both the refractive index grating and the gain grating exist in a 1.55um DFB laser with two cleaved mirror facets, when the phase of ρ_l is fixed to 0 and the phase of ρ_r is changed to -π/2, π, π/2, 0, the change in frequency and oscillation gain was theoretically analyzed. In the case of δL<0, the oscillation gain required for lasing is the lowest and the most stable frequency operation is obtained in the case of (ρ_l phase=0, ρ_r phase=0) and κL=10, when κL is varied from 0.1 to 10. In the case of δL>0, when (ρ_l phase=0, ρ_r phase=π) and κL=10, the oscillation gain required for lasing is the lowest and the difference between the oscillation gains of the higher-order modes is large so that the most stable frequency operation is obtained.

• Korean Journal of Optics and Photonics
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• v.32 no.6
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• pp.286-295
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• 2021

A modified catadioptric omnidirectional optical system (MCOOS) using an RGB/NIR CMOS sensor is optically designed for a capsule endoscope with the front field of view (FOV) in visible light (RGB) and side FOV in visible and near-infrared (NIR) light. The front image is captured by the front imaging lens system of the MCOOS, which consists of an additional three lenses arranged behind the secondary mirror of the catadioptric omnidirectional optical system (COOS) and the imaging lens system of the COOS. The side image is properly formed by the COOS. The Nyquist frequencies of the sensor in the RGB and NIR spectra are 90 lp/mm and 180 lp/mm, respectively. The overall length of 12 mm, F-number of 3.5, and two half-angles of front and side half FOV of 70° and 50°-120° of the MCOOS are determined by the design specifications. As a result, a spatial frequency of 154 lp/mm at a modulation transfer function (MTF) of 0.3, a depth of focus (DOF) of -0.051-+0.052 mm, and a cumulative probability of tolerance (CPT) of 99% are obtained from the COOS. Also, the spatial frequency at MTF of 170 lp/mm, DOF of -0.035-0.051 mm, and CPT of 99.9% are attained from the front-imaging lens system of the optimized MCOOS.

• Journal of Marine Life Science
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• v.7 no.2
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• pp.129-138
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• 2022

Crucian carp, Carassius carassius (Weight 42.4 ± 9.0 g, Length 15.0 ± 1.0 cm) were exposed to waterborne zinc at 0, 5, 10, 20, 40 and 80 mg Zn²⁺/l for 96 hours. The lethal concentration 50 (LC₅₀) at 96 hours of crucian carp, C. carassius exposed to waterborne zinc was 51.58 mg Zn²⁺/l. In hematological parameters, the RBC count was significantly decreased in the concentration of 40 mg Zn²⁺/l at 48 hours, whereas the hematocrit was significantly increased by zinc exposure. The MCV (mean corpuscular volume) (µl) and MCH (mean corpuscular hemoglobin) (pg) were significantly increased in the concentration of 40 mg Zn²⁺/l at 48 hours. The plasma components such as calcium, magnesium, glucose, cholesterol, total protein and ALT (Alanine aminotransminase) were significantly changed by zinc exposure. The results of this study suggest that the zinc exposure to C. carassius induced the significant physiological changes in the hematological parameters and plasma components as toxicity.

• International Journal of Computer Science & Network Security
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• v.22 no.8
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• pp.197-207
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• 2022

Given the prevalence of violence in Ukrainian families, measures to prevent parental abusive treatment against children are urgent. It is important to study today's youth awareness about violence within families in order to enhance a culture of engagement with spouses and children in future. The aim of the study is to examine students' reflective experiences and their attitudes towards forms, frequency, causes and effects of parental abusive treatment. During the research the following methods were used step-by-step: theoretical analyses of scientific resources, anonymous questionnaire, quantitative and correlation analyses. According to result of survey 98 students who were interviewed, none of them fell victim of sexual abuse in their families. However, more than a half (51%) of the students surveyed experienced some forms of parental physical punishment. All the interviewed students encountered psychological cases of parental violence. The mostprevalent forms of parental abuse among the interviewees are criticism, negative comparison, emotional detachment, arrogance, intimidation, blackmail and humiliation. The most prevalent consequences of parental abuse among students are anxiety, low self-esteem, insecurity, impatience, suspiciousness, constraint in communication. Students agree that budget limitations, forced labor, criticism, spanking, emotional detachment, ignoring type of communication, reproach, blackmail are acceptable methods of punishment to use when raising their own children. These results clearly demonstrate the problem of the impact of parental abuse on children and its consequences in the future. A virtual dimension of the actualized problem is considered, namely: - virtualization of aggression and cruelty in the postmodern world. - the level of determining the factor of cruelty from the space of virtual culture. - the mirror image of everyday cruelty in the virtual environment; - the phenomenon of video games as a source and context of representation of the factor of cruelty in behavioral realities; - cybercrime as a virtualized result of cruelty in family and everyday realities. - futurological perspectives of virtualization of cruelty in communicative culture in general and in family relations in particular. The postmodern world is fundamentally different from the traditions and culture of the past, primarily due to the development of computer technologies and the virtualization of life in general. So, for example, virtual communities have become, in a certain way, another world, a second reality of life in general. And certain behavioral factors, in particular cruelty in the private environment, became a projection of such a phenomenon as cybercrime. Video games are a unique modern phenomenon, which multipolarly absorb all facets of human potential, communicative tendencies, behavioral and characterological factors, from the warmth of interpersonal relationships to the extreme degree of cruelty.

• The Journal of the Convergence on Culture Technology
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• v.8 no.6
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• pp.261-268
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• 2022

No language can be separated from other languages and exist independently. When a language comes in contact with a foreign culture, they continuously affect each other and bring changes. Hallyu boom(Korean wave), which was derived from the emergence of K-drama and K-pop due to rapid developments in global scientific technologies and digitization after the 90's, affected the Chinese language. As a result, neologisms that are derived from the Korean language are being commonly used for making exchanges and becoming social buzzwords. Neologisms derived from Korean reflect the effects and results of language contact between the two languages. We examined the background and cause of Chinese neologisms derived from Korean based on the sociocultural factors and psychological necessity, and explained neologisms by using four categories of transliteration, liberal translation, borrowing Korean-Chinese characters and others. Despite having the issue of being anti-normative during the process of coining new words, neologism enriches Chinese expressions and is a mirror for social culture that reflects the opinions and understandings of young Chinese people who pursue novelty, change, innovation and creativity in linguistic aspects. We hope that it will serve as an opportunity for the young people in Korea and China to change their perceptions and become more friendly by understanding each other's language, culture and by communicating. We also expect to provide assistance in regard to teaching and learning the applications of Korean-Chinese language fusion at Chinese education fields.

• Journal of Korean Elementary Science Education
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• v.41 no.2
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• pp.186-198
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• 2022

With the science curriculum about to be revised in 2022, this study aimed to guide curriculum revision by addressing suggested approaches to the electromagnetism education in elementary school science curriculum. The core concepts of electromagnetism are "electric field" and "magnetic field" as a medium of force, but the current curriculum does not properly describe the core concepts of electromagnetism. Mechanics and electromagnetism should be linked in elementary schools to form science curriculum based on core concepts to solve this problem. Additionally, the nine aspects of technology extracted in this study offer various educational contexts to match the development of engineering technology based on electromagnetism. However, the current curriculum does not comprise these various contexts and focuses on the limited content of electric circuits using light bulbs. Therefore, it is necessary to expand the scope of the curriculum to better mirror real-life technology. Through the use of more diverse materials and contexts, the scope and level of STS education as well as conceptual learning could be expanded. Finally, in the case of electric circuit learning, various issues such as difficulty in connecting electric circuits and electric field concepts, representativeness of electric circuit, students' learning difficulty, and phenomena-oriented learning should be considered.

• Korean Journal of Optics and Photonics
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• v.33 no.2
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• pp.74-83
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• 2022

The entire process, from the raw material to the final system qualification test, has been developed to fabricate a large-diameter, lightweight reflective-telescope system for a satellite observation. The telescope with 3 anastigmatic mirrors has an aperture of 700 mm and a total mass of 66 kg. We baked a silicon carbide substrate body from a carbon preform using a reaction sintering method, and tested the structural and chemical properties, surface conditions, and crystal structure of the body. We developed the polishing and coating methods considering the mechanical and chemical properties of the silicon carbide (SiC) body, and we utilized a chemical-vapor-deposition method to deposit a dense SiC thin film more than 170 ㎛ thick on the mirror's surface, to preserve a highly reflective surface with excellent optical performance. After we made the SiC mirrors, we measured the wave-front error for various optical fields by assembling and aligning three mirrors and support structures. We conducted major space-environment tests for the components and final assembly by temperature-cycling tests and vibration-shock tests, in accordance with the qualifications for the space and launch environment. We confirmed that the final telescope achieves all of the target performance criteria.

• Journal of The Korean Association For Science Education
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• v.43 no.4
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• pp.333-349
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• 2023

This study employs Lacan's psychoanalytic approach to reinterpret the images of others and teachers that influence the process of self-formation within the teaching profession as students enter a university of education Seventy-four first- and second-year students majoring in science education at the College of Education from three regions across the country participated in this study, which was conducted using Lacan's L schematic as a representative theoretical framework. Through qualitative analysis and a word cloud analysis, it was confirmed that the students developed perceptions of the teaching profession based on somewhat fictitious and unrealistic teacher images, while others actively intervened in the process of career decision-making. In addition, although parents or teachers mainly occupied the realm of the Other, it was found that they failed to appropriately fulfill the role of the Other, in that they should have corrected the fictional image of teachers. Accordingly, it is necessary to recognize the limitations of ego-psychological career education that can deepen fixations on distorted self-images and, therefore, seek a new career education and counseling model through a psychoanalytic approach.