• Journal of Welding and Joining
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• v.15 no.6
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• pp.24-31
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• 1997

2매의 금속을 맞대어 그 한 쪽에 접촉면과 평행하게 고주파진동을 가하면 단 시간에 접합된다. 이공정을 초음파 용접이라고 하며 그 물리적인 본질은 아직 불분명 하지만, 첫째로는 강한 마찰에 의해 금속 자유면의 산화물층이 제거되기 때문이라는 점과 둘째로는 마찰에 의해 금속 표면이 강하게 가열되어 이에 따른 연화에 의해 접합 이 된다고 하는 점이다. 그러나 이와 같이 가열된다고 하더라도 가열은 표면부에만 국한되고 다른 부분은 가열되지 않는다. 따라서 초음파용접은 냉간접합이라고도 한다. 또 가압력과 진동에 의한 힘이 동시에 작용하기 때문에 용접할 면을 미리 청정하게 할 필요는 없고 용접전의 단계에서 자연적으로 청정화가 이루어진다고 하는 사실이 간접 적으로 증명되고 있다. 초음파 용접(Ultrasonic welding)의 특징을 요약하면 고상용접 의 일종으로서 용접중에 국부적으로 고주파 진동에너지와 압력을 가하여 용접하는 방법이다. 이 때 모재를 용융시키지 않고 건전한 야금학적 결합부가 얻어진다는 데에 큰 특징이 있다. 또한 초음파용접은 다른 용접법에 비해 경제성이 매우 높고, 초음파 용접에 필요한 출력이 전기아크 용접에 필요한 출력의 5 - 10%로 충분한 경우가 많다. 초음파 용접은 통상의 방법으로는 용접하기 어려운 동종 금속이나 이종 금속의 용접에 널리 사용된다. 이 용접법은 반도체, 미세회로, 전기 접점의 형성에 대한 생산기술 로서 사용되고 있는데 소형 모터, 알루미늄 박의 가공, 알루미늄 합금의 조립 등에 이용되고 있다. 한편 최근에는 자동차, 우주항공산업 분야의 구조제 용접용으로도 채용되고 있다.출함이 바람직하다.분비되는 배설-분비 항원의 자극과 깊은 관계가 있음을 알 수 있었다.넌트 명세서를 대한 XML DTD(Document Type Definition)를 정의하고, HTML 기반 검색 방법과 XML 기반 검색 방법에 대한 컴포넌트 검색 성능을 비교한다.따라 NO 생산 및 세포독성이 증가하였고. NO 생산을 저하시키는 약제들은 활성화된 복강 대식세포 및 RAW264.7 세포에 의한 질편모충에 대한 세포독성을 현저히 감소시키는 것으로 보아 NO는 질편모충에 대한 대식세포의 숙주 방어기전에서 중요한 역할을 감당할 것으로 생각된다.nction index) 와 최대개구시 동통의 정도는 시술전과 시술 4주후간에 유의한 차이가 관찰되었다.피부온도는 검사자간에는 특정부위에 따라 다소 차이가 있을 수 있으나 일반적으로 높은 재현성을 보여줌으로서 향후 교근 및 측두근의 임상연구 평가에 피부온도조사는 도움이 되리라 사료된다. lactobacilli의 양은 peroxidase system을 함유하거나(p < 0.01) 함유하지 않은(p < 0.05) 치약을 사용한 군 모두에서 양치전에 비해 유의성있게 감소하였다. 6. 양치후 30분에 채취한 구강건조증 환자의 자극성 전타액내 S. mutans 양은 peroxida system을 함유한 세치제를 사용한 군에서 대조군에 비해 유의성있게 낮았다(p < 0.05). 7. 양치후 30분에 채취한 구강건조증 환자의 자극성 전타액내 lactobacilli양은 peroxidase system을 함유한 세치제를 사용한 군에서 대조군에 비해 상대적으로 낮게 나타났으나(p = 0.067)

• Applied Microscopy
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• v.36 no.3
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• pp.195-208
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• 2006

Using light and scanning electron microscopy morphological studies of pollens were conducted to determine the sectional boundary and the relationships among eight species of section Zygophyllidium and its five related species of subg. Poinsettia. Pollen characters of 13 species were described, and their diagnostic keys were presented here. Based on the sculpturing patterns and the results of numerical analysis using 10 pollen characters 13 species were divided into four Pollen types: type I, having micro-reticulate shaped pollen (E. hexagona, E. lagunensis, E. hexagonoides and E. bilobata), type II, having reticulate shaped pollen (E. delicatula, E. extipulata, E. dentata, E. heterophylla, E. pulcherrima and E. cyathophora), type III, micro-reticulate shaped pollen with platten muri (E. lacera), and type IV, haying foveolate shaped pollen grains (E. chersonesa and E. eriantha). The results of pollen morphological studies suggest that the sect. Zygophyllidium should be delimited based on only four species, E. hexagona, E. lagunensis, E. hexagonoides and E. bilobata, E. delicatural and E. exstipulata of sect. Zygophyllidium must be transferred to subg. Poinsettia based on pollen morphology. E. eriantha and E. chersonesa having forveolate sculpturing pattern of pollen grains seem to be closely related with species from subg. Agaloma, and additional studies of these species are needed to determine the species relationships within Agaloma group.

• Journal of Science Education
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• v.42 no.2
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• pp.242-255
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• 2018

Recently, flipped learning has been paid much attention as one of the improvement methods of teaching and learning at university level. Few studies investigated the effects of flipped learning in general physics classes. However, in order to be successfully established and spread new attempts such as flipped learning, it is necessary to investigate in detail the effect of flipped learning and the way it is perceived by students in accordance with other variables such as student's background and characteristic. In this study, we investigated differences in students' perception on the flipped learning and their achievement according to their background and characteristic in flipped-learning-based introductory physics course in which class hours are divided into lecture and group problem solving equally. Students' achievement was more influenced by their readiness before the beginning of the semester than their time consuming for learning during the semester. Students generally had a very positive perception of the new way of flipped-learning-based physics teaching. However, students of insufficient prior learning, or relatively not-hard learner agreed with careful selection of subjects rather than the overall expansion of flipped learning.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.2
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• pp.256-261
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• 2005

Scleroderma is a connective tissue disease of unknown etiology, but known as a kind of auto-immune disease. It is most common in women especially in $30{\sim}50$ years, and very rare in childhood. It can be classified into two main classes : localized scleroderma & systemic sclerosis. Localized type has better prognosis, and usually involves skin only, or in some cases, the muscle below, except inner organs. Systemic type involves skin, oral mucosa and major internal organs. Involving facial skin, we can see small and sharp nose, expressionless stare and narrow oral aperture. Usually they have Raynaud's phenomenon, and in progress, show mouth opening limitation and sclerosis of tongue and gingiva. It is called CREST syndrome showing calcinosis cutis, Raynaud's phenomenon, esophageal dysfunction, sclerodactyly, and telangioectasia. Treatment of scleroderma is systemic and localized steroid therapy, use of collagen-link inhibitor (D-penicillamine), immune depressor and etc. Mouth opening limitation can be improved by mouth stretching exercise. We report a 6 years old boy, diagnosed with localized scleroderma who had mouth opening limitation. We could get additional mouth opening, and have done successful restorative treatment of mandibular and maxillary 1st and 2nd deciduous molar under deep sedation with nitrous oxide and enflurane.

• Journal of the Korea Society of Computer and Information
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• v.16 no.11
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• pp.67-76
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• 2011

This paper describes the development of interactive visualization techniques and a program that allow us to visualize the structure of the volume data and interactively select and visualize the isosurface components using contour tree. The main characteristic of this technique is to provide an algorithm that draws the contour tree in 2D plane in a way that users easily understand the tree, and to provide an algorithm that can efficiently extract an isosurface component utilizing GPU's parallel architecture. The main characteristic of the program we developed through implementing the algorithms is to provide us with an interactive user interface based on the contour tree for extracting an isosurface component and visualization that integrates with previous isosurface and volume rendering techniques. To show the excelland vof our methods, we applied 3D biomedical volume data to our algorithms. The results show that we could interactively select the isosurface components that represent a polypeptide chain, a ventricle and a femur respectively using the user interface based on our contour tree layout method, and extract the isosurface components with 3x-4x higher speed compared to previous methods.

• Clinical and Experimental Pediatrics
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• v.48 no.12
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• pp.1317-1323
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• 2005

Purpose : This study was performed to evaluate the recent frequency of karyotypes in different sex chromosome abnormalities and to evaluate the age and clinical manifestations at diagnosis. Methods : Peripheral blood leukocytes were obtained from subjects who were clinically suspected to have sex chromosome abnormalities and referred to the cytogenetic laboratory in the Department of Pediatrics, Kyungpook National University Hospital from February 1981 to August 2001. Results : The relative frequencies of different sex chromosome abnormalities were Klinefelter(52 percent), Turner(42 percent), XXX syndrome(3 percent) and mixed gonadal dysgenesis(3 percent). The populations of different karyotypes in Klinefelter syndrome were 47,XXY(97 percent) and 46,XY/47,XYY(3 percent). The populations of different karyotypes in Turner syndrome were 45,X(67 percent,), mosaicism(23 percent), and structural aberrations(10 percent). The populations of different karyotypes in XXX syndrome were 47,XXX(67 percent,) and 46,XX/47,XXX(33 percent). All mixed gonadal dysgenesis were 45,X/46,XY. Eighty one percent of sex chromosome abnormalities was diagnosed after puberty. Patients diagnosed with Klinefelter and Turner syndrome in infancy showed nearly normal phenotypes or had minor congenital malformations. Conclusion : Early diagnoses of sex chromosome abnormalities is required to prevent associated morbidities and to maximize growth and development. We have to pay careful attention in diagnoses of Turner syndrome because of the high proportion of mosaicism and structural aberrations.

• (The)Study of the Eastern Classic
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• no.41
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• pp.37-59
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• 2010

This thesis is for clarifying a few aspects of 'Kyung(敬)' ideology and figures appearing in Yeheon(旅軒)'s poem. This ideology and figures is a kind of a imaginative thing that a poet designed. This feature is a very important subject of Yeheon(旅軒)'s poem world, so that we are going to make it clear. First, we focused his aspirations of virtual uncontaminated areas and found out his big store of life wisdom and knowledge. The second is we thought about a displaying a emphasis of proud spirit[氣像] in his own poem world, and we found that he saw things from an unworldly point of view. Finally we talked about several features of Yeheon(旅軒)'s poem world. Now we have to compare Yeheon(旅軒)'s poem and any other Dohakpa(道學派) poets for example Toegye(退溪), Hwejae(晦齋) etc. And we must clarify the whole poem world of Dohakpa(道學派). In the end, I'm so sure that we will get a prospect of their literature.

• Journal of the Korean Chemical Society
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• v.66 no.5
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• pp.362-375
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• 2022

In this study, science teachers' NOS lessons were observed and the characteristics of the lessons were analyzed. Three science teachers who taught NOS in the 'Science Inquiry Experiment' developed under the 2015 revised curriculum participated in the study. Their NOS lessons were observed and interviews were conducted before and after lessons. The collected data were analyzed using analytical induction and constant comparative method. The analyses of the result revealed the teachers' naive views on NOS were also revealed during the lessons. There were some cases where they showed naive views during the lessons even if they showed informed views in the interviews. Although the domains of NOS taught by them were diverse, all of them taught 'tentativeness' and considered this an important goal. They tended to teach NOS with content related with their major, and teaching NOS was found to be deeply related to their major. In the activity where students learn NOS by inferring the unknown object, teachers disclosed the unknown object, which is unlike the rule of the activity. They thought that could help students' learning. At last, although they emphasized teaching NOS, they either did not assess NOS or assessed NOS in a limited way. Based on the results, some directions for teacher education and follow-up study are suggested.

• Journal of the Korea Society of Computer and Information
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• v.28 no.10
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• pp.133-153
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• 2023

In this paper, we propose a novel approach to investigating brain-signal measurement technology using Electroencephalography (EEG). Traditionally, researchers have combined EEG signals with bio-signals (BSs) to enhance the classification performance of emotional states. Our objective was to explore the synergistic effects of coupling EEG and BSs, and determine whether the combination of EEG+BS improves the classification accuracy of emotional states compared to using EEG alone or combining EEG with pseudo-random signals (PS) generated arbitrarily by random generators. Employing four feature extraction methods, we examined four combinations: EEG alone, EG+BS, EEG+BS+PS, and EEG+PS, utilizing data from two widely-used open datasets. Emotional states (task versus rest states) were classified using Support Vector Machine (SVM) and Long Short-Term Memory (LSTM) classifiers. Our results revealed that when using the highest accuracy SVM-FFT, the average error rates of EEG+BS were 4.7% and 6.5% higher than those of EEG+PS and EEG alone, respectively. We also conducted a thorough analysis of EEG+BS by combining numerous PSs. The error rate of EEG+BS+PS displayed a V-shaped curve, initially decreasing due to the deep double descent phenomenon, followed by an increase attributed to the curse of dimensionality. Consequently, our findings suggest that the combination of EEG+BS may not always yield promising classification performance.

• Journal of Christian Education in Korea
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• v.78
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• pp.87-110
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• 2024

The purpose of this study is to explore the educational philosophy that is the basis for the establishment of Christian alternative schools and the curriculum that is the standard for educational practice accordingly, and to understand in depth the educational philosophy and curriculum, what characteristics are common in each type in the school field. This study also explored the main factors that lead to educational practice in the curriculum. In order to explore these research questions, this study was conducted using interview that is one of the qualitative studies. The subjects of this study are 16 teachers selected from the three types of Christian alternative schools that exist in Korea. Based on our findings and discussion, this study was presented several suggestions. First, in the reality that parents are sending their children to alternative schools for their faith, school leaders and teachers must practice sincere faith education with deep reflection. Second, in order for Christian alternative schools to fulfill their responsibilities as schools and continue to provide a valuable education, it is necessary to integrate Christian worldviews and academics through cooperation with allied organizations. Third, in order to reduce the burden of parents' excessive educational expenses, there should be a civic effort to request financial support from the nation at least for school operating expenses.