• Journal of Powder Materials
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• v.28 no.2
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• pp.164-172
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• 2021

Titanium is the ninth most abundant element in the Earth's crust and is the fourth most abundant structural metal after aluminum, iron, and magnesium. It exhibits a higher specific strength than steel along with an excellent corrosion resistance, highlighting the promising potential of titanium as a structural metal. However, titanium is difficult to extract from its ore and is classified as a rare metal, despite its abundance. Therefore, the production of titanium is exceedingly low compared to that of common metals. Titanium is conventionally produced as a sponge by the Kroll process. For powder metallurgy (PM), hydrogenation-dehydrogenation (HDH) of the titanium sponge or gas atomization of the titanium bulk is required. Therefore, numerous studies have been conducted on smelting, which replaces the Kroll process and produces powder that can be used directly for PM. In this review, the Kroll process and new smelting technologies of titanium for PM, such as metallothermic, electrolytic, and hydrogen reduction of TiCl₄ and TiO₂ are discussed.

• Clinical and Experimental Pediatrics
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• v.65 no.3
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• pp.115-126
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• 2022

Retinopathy of prematurity (ROP) is among the most common causes of childhood blindness. Three phases of ROP epidemics have been observed worldwide since ROP was first described in the 1940s. Despite advances in neonatal care, the occurrence of ROP and associated visual impairment has been increasing somewhere on Earth and remains difficult to control. Conventional treatment options for preventing ROP progression include retinal ablation using cryotherapy or laser therapy. With the emergence of anti-vascular endothelial growth factor (anti-VEGF) treatment for ocular diseases, the efficacy and safety of anti-VEGF therapy for ROP have recently been actively discussed. In the advanced stage of ROP with retinal detachment, surgical treatment including scleral buckling or vitrectomy is needed to maintain or induce retinal attachment. At this stage, the visual outcome is usually poor despite successful anatomical retinal attachment. Therefore, preventing ROP progression by timely screening examinations and treatment remains the most important part of ROP management.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.26 no.1
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• pp.1-14
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• 2023

Foreign body (FB) ingestion is a common health problem that affects children more than adults. According to gastroenterologists' guidelines, the management of FB ingestion differs slightly between adult and children. This review aimed to compile adult and children guidelines and establish an understandable association to reveal the requirements and timing of the endoscopic procedure, which is the most effective and least complicated technique for gastrointestinal FBs. Coins, pins, and chicken and fish bones have been the most commonly ingested FBs. However, with their increasing use in recent years, large batteries with lithiumion conversion, stronger magnets composed of rare earth metals, such as neodymium, and superabsorbent objects have become the most morbid and mortal, necessitating new management strategies. Although the approach to gastrointestinal FBs is controversial, with different treatment options available in different disciplines, many studies have demonstrated the efficacy and safety of endoscopic procedures. Many factors influence the timing of endoscopy, including the nature, size, and location of the ingested object and the patient's clinical condition.

• Korean Journal of Remote Sensing
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• v.37 no.2
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• pp.337-357
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• 2021

Because the growth of paddy rice is affected by meteorological factors, the selection of appropriate meteorological variables is essential to build a rice yield prediction model. This paper examines the suitability of multiple meteorological datasets for the rice yield modeling in South Korea, 1996-2019, and a hindcast experiment for rice yield using a machine learning method by considering the nonlinear relationships between meteorological variables and the rice yield. In addition to the ASOS in-situ observations, we used CRU-JRA ver. 2.1 and ERA5 reanalysis. From the multiple meteorological datasets, we extracted the four common variables (air temperature, relative humidity, solar radiation, and precipitation) and analyzed the characteristics of each data and the associations with rice yields. CRU-JRA ver. 2.1 showed an overall agreement with the other datasets. While relative humidity had a rare relationship with rice yields, solar radiation showed a somewhat high correlation with rice yields. Using the air temperature, solar radiation, and precipitation of July, August, and September, we built a random forest model for the hindcast experiments of rice yields. The model with CRU-JRA ver. 2.1 showed the best performance with a correlation coefficient of 0.772. The solar radiation in the prediction model had the most significant importance among the variables, which is in accordance with the generic agricultural knowledge. This paper has an implication for selecting from multiple meteorological datasets for rice yield modeling.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.28 no.3
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• pp.98-104
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• 2010

The objective of this study was to understand the origin and characteristics of stone tower's style through the study of the 'Village Shrine at Seoji-ri, Andong'. The three kinds of stone towers were located forming a line of 9m on the hill of a red pine forest along the stream in the village. Toward the direction looking at the village, the three-story stone located on left, the two-story stone located in the middle, and the common style stone tower located on right. The bottom part of the three-story stone was 2.5m in length, 1.8m in width, 1.3m in height. The bottom part of the two-story stone was 1.3m in length, 1.5m in width, 0.9m in height. The common style stone heap tower was 3.0m in diameter, 1.8m in height with a cone shape. The small hat-shaped stone was presumed to be the top part of a three-story stone. According to the three factors(heaven, earth, human) of the idea of the universe in Korea, most ancient remains have components of odd numbers. Then it had been substituted with smaller three-story stone(at present, two-story stone). And then altered to a common stone tower later, such as the 'Village Shrine at Seoji-ri, Andong' that shows the combination of the Bronze Age's megalithic and a folk religion. The 'Village Shrine at Seoji-ri, Andong' is a valuable relic that shows the stone towers, and is derived from the Bronze Age. The 'Village Shrine at Seoji-ri, Andong' shows that the 'Village Shrine at Seoji-ri, Andong' was embodied the three-factor(heaven, earth, human) idea of the universe in three-story stone of megalithic culture' remains.

• Journal of the Korean Society of Earth Science Education
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• v.13 no.1
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• pp.53-63
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• 2020

The purpose of this study is to analyze the current status of the second year of application of Integrated Science and Science Laboratory Experiments, which are common courses of high school, and to explore suggestions for curriculum development in the future. To this end, the results of the survey of a total of 244 science-core and general high schools were compared with the survey result of 2018 school year. In addition, in-depth interviews were conducted with nine science teachers of the focus group to discuss the current state of curriculum implementation. According to the results, as in the first year, most of the Integrated Science courses were implemented in 6-8 units, and in most schools the number of teachers in charge of Integrated Science per class were 3-4. In the teacher's focus group interview, teachers insisted that Integrated Science requires integrated teaching approaches and is good for generating students' interest, but it is difficult to implement process-based assessment due to issues such as ensuring fairness of assessment. Most of Science Laboratory Experiments courses were implemented in two semesters, one unit per semester, and there was little link between Integrated Science and Science Laboratory Experiments because of the different teaching staff. The school life record entry method of Science Laboratory Experiments has been changed to criterion-based assessment starting in 2019, so students' satisfaction or flow of classes is much better than expected, and teachers can teach without burden. Based on the research results, ways to support the settlement of Integrated Science and Science Laboratory Experiments as common subjects, and ways to improve those subjects in the next curriculum revision were suggested.

• Journal of the Korean earth science society
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• v.24 no.7
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• pp.625-634
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• 2003

This study was designed to analyze the differences in science achievement and satisfaction between the environments of Face-To-Face (FTF) and Computer Mediated Communication (CMC), and between the interactions of Teacher-Students (TS) and Students-Students (SS). The activities for the interaction in the FTF and the CMC were carried out in the environments of traditional classrooms and the on-line network of communication computer, respectively. These experiments for four different groups (CMC-TS, CMC-SS, FTF-TS and FTF-SS) were performed with respect to 103 students of three 10th grade classes at a girls' high school in Chungju city. The questionnaires were composed of 5questions for achievement, and 13 questions on Likert scale for satisfaction. The data was analyzed using ANOVA, and through examination of each question about the satisfaction. The mean of the science achievement in learning activity was significantly higher in the CMC environment than the FTF. Also, the score in the TS interaction was meaningfully higher than the SS. Under the common environment of the CMC, science achievement and satisfaction in the TS interaction were significantly higher than in the SS. A similar result has been obtained in the satisfaction case even in the common environment of the FTF. The itemized analysis for the satisfaction shows a high score in the individual condition of CMC and TS, compared to that of FTF and SS, respectively. Thus, the school activity, formed in the TS interaction in the CMC environment is more effective at improving science achievement and satisfaction in the teaching and learning of science.

• Journal of the Korean Society of Hazard Mitigation
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• v.7 no.5
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• pp.129-137
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• 2007

It is very urgent to research the proper recycling method of marine dredged soil as construction material for environmental conservation. Couple of developed countries have been lots of related researches on recycling of marine dredged soil for marine environmental conservation. This is highly imperative in our country. A small-scaled model test for underground pipe has been conducted on the use of controlled low strength materials with marine dredged soil. The flexible pipe, which is called PVC, was used. Four different testing materials, such as natural sand, insitu-soil, sand-CLSM with marine dredged soil and insitu-soil CLSM with marine dredged soil, were used. The vertical and lateral displacement of pipe with CLSM is one tenth of common granular materials. Also, the use of CSLM showed lower lateral and vertical pressure than that of common granular materials. The main reason is the effect of cement hardening of CLSM. This could increase of the stiffness of pipe with backfill materials. In this study, the data presented show that marine dredged soil and in-situ soil can be successfully used in CLSM and reduce the deformation and earth pressure on flexible pipe.

• Journal of the Daesoon Academy of Sciences
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• v.20
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• pp.169-191
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• 2009

The Four Tenets of Daesoon thought are the Creative conjunction of the virtues of Eum and Yang, the Harmonious union of divine beings and human beings, the Resolution of grievances for the mutual beneficence of all life and the Realization of the Dao in the world. This article compares the concepts of the "Creative conjunction of the virtues of Eum and Yang", the "Harmonious union of divine beings and human beings" and the "Resolution of grievances for the mutual beneficence of all life" with "EumYangDaeDaeRon", "ShinMyonKiDeok", the Theory of Mutual Giving Life / Mutual Destruction (SangSaeng/SangGeukRon) of the Book of Changes and analyzes their common and different points. The conclusion is that Daesoon thought and the philosophy of the Book of Changes share common fundamental standpoints. However, the Daesoon thought defines the world of SeonCheon (the state before the Heaven and Earth have been created) as Mutual Giving Life (SangSaeng), and the world of HuCheon (the state after the Heaven and Earth have been created) as Mutual Destruction (SangGeuk). According to Daesoon thought the Mutual Destruction (SangGeuk) is seen as negative, while according to the philosophy of the Book of Changes the Theory of Mutual Giving Live/Mutual Destruction (SangSaeng/SangGeukRon) is viewed as a positive relationship of EumYangDaeDae. This is a point of difference between the Daesoon thought and the philosophy of the Book of Changes. According to EumYangDaeDae relationship theory the contradictory "other" is viewed not as an enemy, but as a necessary element that assures one's existence. When Buddhism and Christianity first came to existence, they did not belong to a main stream. Later, through continuous theorization and systematization they became generally accepted religions. The case of Confucianism was not much different. During Song dynasty in China Buddhism has contributed to the systematization and establishment of Neo-Confucianism; in the middle of 20th century the Confucian scholars of Hong Kong and Taiwan interpreted and defined Confucianism a new in the light of Western philosophy. Thus the "Modern Neo-Confucianism" came to existence. That's why the history of Confucianism is also called "the history of advancing and developing a concept". From this point of view the critical acceptance of some elements of Confucian, Buddhist, Taoist etc. traditions, as well as modern philosophy, by Daesoon, in order to achieve the systematization of Daesoon thought, is a very important process. As a part of this process, this essay explains the Daesoon thought from the point of view of the Book of Changes, which may be said to present the original East-Asian view of the world. Daesoon's emphasis of human dignity, the equality of sexes, the critics the hierarchical society etc. are rather "modern" and should be examined from the point of view of social science. Besides, leaving the boundaries of "modern philosophy", the concepts of "Harmonious union of divine beings and human beings", viewing the universe as one organism etc. should be approached from the point of view of Post-Modernism.

• Journal of the Korean Society of Earth Science Education
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• v.4 no.3
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• pp.242-250
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• 2011

The present study compared the contents and methods of elementary science education in schools and education institutes for the gifted and surveyed the contents and methods of science education for the gifted desired by students in order to set the direction of elementary science education at education institutes for the gifted. For this study, we conducted interviews with a 5th-grade male student and a 6th-grade female student at the science class of the Education Institutes for the Gifted run by Iksan Education Office. Besides, printed materials were collected and used to refer to the contents of education. The results of this study are as follows. First, in school, the student learn according to the curriculum defined by the government and the contents begin with elementary and basic ones and move step by step to deeper and wider scientific principles. On the contrary, in the education institute for the gifted, the contents of teaching materials are decided at the teacher's discretion, and because they target gifted children, their level is higher than that of the science curriculum in school. Second, the most common teaching method in school is lecturing and, next, experiments, group activities, etc. On the contrary, in the education institute for the gifted, experiments are used most frequently, and various educational methods are adopted including lectures, project learning and cyber learning. Third, the contents of science education that gifted children wanted to learn are not limited to any specific area. Science education methods that gifted children wanted were various, including project learning, group activities, experiments, and report making and presentation.