• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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• pp.644-651
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• 2002

The formation and stability of stationary laser weld keyholes are investigated using a numerical simulation. The effect of multiple reflections in the keyhole is estimated using the ray tracing method, and the free surface profile, flow velocity and temperature distribution are calculated numerically. In the simulation, the keyhole is formed by the displacement of the melt induced by evaporation recoil pressure, while surface tension and hydrostatic pressure oppose cavity formation. At laser powers of 500W and greater, the protrusion occurs on the keyhole wall, which results in keyhole collapse and void formation at the bottom. Initiation of the protrusion is caused mainly by collision of upward and downward flows due to the pressure components.

• Educational Technology International
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• 제12권1호
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• pp.21-46
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• 2011

International virtual teamwork offers new opportunities for the professional development of teachers. In this paper, we examine the initial experiences in an ongoing international virtual benchmarking project coordinated by the Finnish Online University of Applied Sciences. What challenges does an international context present for project construction and collaboration? Data from five countries, in the form of participant reflections and researchers' observations, were analysed according to four types of barriers: language, time, technical and mental barriers. Initial data indicates that trust is an essential starting point, as there is neither time nor possibilities to build mutual trust by traditional means. Organisational confidentiality issues, however, can complicate the situation. The project introduces 'collision' as a method of professional development, in which physical and organisational borders are crossed and the skills and competencies needed in global learning environments are acquired.

• Child Health Nursing Research
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• 제30권3호
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• pp.167-175
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• 2024

Purpose: To measure the level of reflection, this study analyzes diaries written by third-year nursing students before and after the debriefing stage in simulation training. A qualitative study using diary entries from 15 nursing students to explore reflection depth. Methods: Students engaged in simulation training and the debriefing stage, documenting their reflections in diaries. Before and after debriefing, reflections were rated from Level 1 (reflectivity) to Level 7 (theoretical reflectivity). Results: The total number of reflection levels rose significantly from 545 to 829 post-debriefing, enhancing higher-order reflection. The shift signifies a move from superficial to deep reflection, highlighting debriefing's role in fostering critical thinking. Conclusion: The findings underscore the critical role of debriefing in enhancing reflective thinking in nursing education. There is a demonstrated need for further research into the specific elements of debriefing that are most effective at promoting deep reflection. Future studies should conduct comparative analyses of different debriefing methods and approaches across various educational settings. This research could lay the foundation for designing more effective debriefing strategies that foster critical thinking and improve learning outcomes in nursing education.

• Kyungpook Mathematical Journal
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• 제35권1호
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• pp.113-144
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• 1995

• 대한통합의학회지
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• 제7권4호
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• pp.171-180
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• 2019

Purpose : The purpose of this study is to understand the experiences of nursing students in clinical practice at a public health center through their self- reflections. Subjects : The 110 students in the 3rd year, practice at two public health centers in city P and city K. From the110, 53 male and female university students who practice in city K were selected to participate : 11males (20.8 %) and 42 females (79.2 %). Methods : The data analyzed were the self-reflections regarding the clinical practice. Results : These data indicate that : most of the participants now believe that public health centers provide many more services to the community than they previously knew about. They rate the public health center's programs highly, and want to be community health nurses. For the first time, they realize that the work of public health nurses is very important. In particular they note that their emotions while at the public health center differ significantly from when they work at the other. The environment in the public health center makes them feel more comfortable and less stressed. Generally, they are satisfied with their practice at the public health center. Conclusion : On the basis of these findings, the following recommendations can be made. Experience at public health centers is an important part of nursing students' education. I suggest that research on nursing students' experiences while practicing at the public health center should expand to include research methods other than the analysis of their reflection journals, In addition a follow-up study of experiences while practicing at the public health center should be attempted of self-reflections.

• 의학교육논단
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• 제24권1호
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• pp.46-55
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• 2022

This study aimed to analyze the subjects, situations, and reflection levels related to role modeling experienced by medical students during their clinical clerkship and their own reflections. This study intends to suggest ways of improving how residents and clinical faculty should treat and teach medical students. Written interviews were conducted regarding senior medical students' role modeling experiences during their clinical clerkships in 2018 and 2019. Content analysis was conducted for a total of 224 cases from 196 students. Content analysis revealed three types of role modeling content: subjects (faculty, residents, nurses, peer students), situations (clinical competence, personal qualities, teaching skills), and the level of reflection (critical reflection, reflection, thoughtful action, and habitual action) in each case. As role model subjects, faculty were found to be the paramount role model (n=142, 62.83%). Role modeling was the most frequently performed for clinical competence (n=103, 45.98%). Clinical competence was frequently shown in communication and empathic listening during rounds and outpatient relationships between the patient and doctor. Regarding the level of reflection for role modeling, the number of critical reflections was 86 (38.39%) and that of reflections was 80 (35.71%). In particular, negative role modeling showed a high level of critical reflection in relation to faculty (64.44%) and nurses (8.89%). In conclusion, role modeling of medical students participating in clinical clerkships occurs in situations that the role models are not aware of, with positive or negative effects on the formation of professional identity among medical students.

• 지구물리와물리탐사
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• 제12권1호
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• pp.69-76
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• 2009

이 논문에서는 성곽의 옛터에서 수행된 GPR탐사 결과에 대해 기술하고자 한다. 이 탐사의 목적은 몽고의 반칸 투리일의 유적지에서 2차원과 3차원 GPR 탐사방법을 이용하여 벽이나 타일 등의 매립되어있는 고고학적 구조물의 특징을 알아내는데 있다. GPR자료는 500 MHz와 800 MHz의 두 주파수의 안테나를 이용하여 10 cm의 측선간격으로 $10m\;{\times}\;9m$의 영역에 대해 획득 되었다. 이 논문에서는 타일, 벽돌. 석조물 등의 고고학적 대상체를 탐지해 내기 위한 편광측정 GPR 탐사기를 통해 얻어지는 순간변수들의 이용에 관해 다루고자 한다. 레이다 편광측정은 대상체의 산란특성을 끌어내는 진보된 기술이다. 이 방법은 대상체의 크기, 모양, 지향성 및 표면의 상태에 대한 보다 많은 정보를 제공해준다. 우리는 해석의 초점을 강한 반사파에 맞추었으며, 영상의 질은 순간변수들을 사유하여 높였다. 반사신호의 모양과 길이를 살펴본 결과 순간진폭의 중간 부터 높은 강도의 반응은 벽돌이나 타일에 대응되는 것을 알 수 있었다. 순간위상을 이용하여 만든 지도는 일반 신호에서 불연속성을 보이던 탐사 대상체의 위치를 알아내는데 중요한 정보를 제공하였다. 이러한 고고학적 대상체의 탐사 가능성을 높이기 위하여, 서로 직교하는 두 측선에 대해 GPR 자료를 획득하였다. 이 두 자료를 비교한 결과 반사신호들의 정렬이 좋은 상관관계를 갖는 것을 확인하였다. 그러나. 북쪽에서 남쪽 방향으로 측정된 탐사 자료에서 서쪽에서 동쪽 방향으로 측정된 탐사자료보다 많은 반사 신호가 관측되었다. 이는 북쪽에서 남쪽으로 수행된 탐사방향과 수평면 상에 위치하게 피는 전기장의 지향성 때문이며 고에너지의 후방산란된 수평 분극 성분이 기록된 것이다.

• 한국과학교육학회지
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• 제33권6호
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• pp.1087-1102
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• 2013

본 연구에서는 예비과학교사들이 교육실습기간 중 수업 실행에서 보이는 반성의 분야와 수준에 대해 알아보았다. 모두 7명의 예비과학교사가 연구에 참여하였으며, 이 중 4명의 예비과학교사는 반성적 사고를 촉진할 수 있는 프로그램을 추가로 제공받았다. 예비과학교사들의 반성은 주로 수업 운영에 관련된 분야인 주의 집중 및 동기 유발 방식, 교수 활동에 대한 반성과 개선, 상호작용 등에서 나타났으며, 과학과 교육과정의 이해 및 재구성과 차시 예고에 대한 반성은 거의 이루어지지 않았다. 반성적 사고를 촉진하는 프로그램을 제공받은 예비과학교사들은 일반적인 교육실습 프로그램에 참여한 예비과학교사들에 비해 반성의 빈도가 높게 나타났다. 예비과학교사들이 반성을 보인 글들은 대부분 기술적 반성에 해당했으며, 반성적 사고를 촉진하는 프로그램을 제공받은 예비과학교사들은 기술적 반성 뿐 아니라 높은 수준의 반성인 대화적 반성도 많이 나타났다. 그러므로 사전 교육프로그램과 반성저널쓰기, 교사들의 수업평가 및 피드백은 예비과학교사들의 반성의 빈도와 수준을 높이는 것으로 보인다.

• 한국광물학회지
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• 제4권1호
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• pp.11-21
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• 1991

1차원적 x-선 회절도형의 계산방법을 이용하여 Biedellite-nontronite 와 saponite-iron sponite의 X-선 회절현상을 조사하였다. 에틸렌 글리콜 처리된 스멕타이트는 수화된 스멕타이트보다 강한 002와 003 회절선을 나타내는데, 002와 003회절선은 Fe 성분의 함량에 따라서 그 강도가 점진적으로 변화한다. 에틸렌 글리콜처리된 dioctahedral 스멕타이트와 trioctahedral 스멕타이트에서 002/003 회절선 강도비율은 스멕타이트내에 Fe성분이 많아짐에 따라 높아진다. 이러한 비율의 변화는 Al이나 Mg보다 훨씬높은 Fe성분이 많아짐에 따라 높아진다. 이러한 비율의 변화는 Al이나 Mg보다 훨씬높은 Fe의 scattering factor에 기인한 것이며, octahedral 양이온들의 scatterinf factor들을 계산함으로써 여러 스멕타이트들의 X-선 회절선들을 정량적으로 비교할 수 있다. Interlayer 양이온들은 Fe등의 octahedral양이온들에 비해서 X-선 회절선들에 경미한 영향을 미친다. 00l회절선들이 octahedral sheet의 전반적인 회절선강도에 관한 자료를 제공하지만, Fe 성분이 많은 일부 dioctahedral 스멕타이트들은 1차원적 X-선 회절도형만으로는 trioctahedral 스멕타이트로부터 명확하게 구분될 수 없다. 1차원적 X-선 회절도형의 계산에 의하면 복합체로 이루어진 이질의 스멕타이트의 00l회절선 분포양상은 이 이질의 스멕타이트 화학성분이 평균 성분에 해당하는 균질 스멕타이트와 거의 같다. 회절선이 넓어지는 현상에 관련된 여러 요소들이 잘 파악되지 않으면, 00l회절선들이 넓어지는 정도르 스멕타이트의 이질도를 판단하기 위해 응용하는 데는 문제점이 있는 것으로 사료된다.

• Bulletin of the Korean Chemical Society
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• 제14권5호
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• pp.603-610
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• 1993

The crystal structure of dehydrated $Ag_{5.6}K_{6.4}-A$, zeolite A ion-exchanged with $K^+\;and\;Ag^+$ as indicated and dehydrated at 360$^{\circ}$C, has been determined by single-crystal X-ray diffraction techniques. Also determined were the structures of the products of the reactions of this zeolite with 0.1 Torr of Cs vapor at 250$^{\circ}$C for 48 h and 72 h, and with 0.1 Torr of Rb vapor at 250$^{\circ}$C for 24 h. The structures were solved and refined in the cubic space group Pm3m at 21(l)$^{\circ}$C (a= 12.255(l) ${\AA}$ , 12.367(l) ${\AA}$, 12.350(l) ${\AA}$, and 12.263(l) ${\AA}$, respectively). Dehydrated $Ag_{5.6}K_{6.4}$-A was refined to the final error indices $R_1= 0.044\;and\;R_2=0.037$ with 202 reflections for which I>3${\sigma}$(I). The crystal structures of the reaction products were refined to $R_1=0.087\;and\;R_2= 0.089$ with 157 reflections, $R_1=0.080\;and\;R_2= 0.087$ with 161 reflections, and $R_1= 0.071\;and\;R_2=0.061$ with 88 reflections, respectively. In the structure of $Ag_{5.6}K_{6.4}-A,\;K^+$ ions block all 8-oxygen rings, and one reduced Ag atom is found per sodalite cavity. Also, ca. 4.6 $Ag^+ ions\;and\;3.4 K^+ ions$ are found at 6-ring sites in the large cavity. The crystal structures of the reaction products show that all $K^+$ and $Ag^+$ ions have been reduced, and that all K^+$ atoms have left the zeolite. Cs or Rb species are found at three different crystallographic sites: 3.0 $Cs^+\;or\;3.0Rb^+$ ions per unit cell occupy 8-ring centers, ca. 8.0 $Cs^+ ions\;or\;5.7 Rb^+$ ions, are found on threefold axes opposite 6-rings deep in the large cavity, and ca. 2.5 $Cs^+\;or\;2.3 Rb^+ ions are found on threefold axes in the sodalite unit. Also, 1 $Rb^+$ ion lies opposite a 4-ring. Silver atoms, corresponding to 75% or 40% occupancy of hexasilver clusters stabilized by coordination to $Cs^+\;or\;Rb^+$ ions, are found at the centers of the large cavities. In the crystal structures of dehydrated Ag_{5.6}K_{6.4}-A$ reacted with Cs vapor, excess Cs atoms are absorbed and these form (locally) cationic clusters such as $(Cs_4)3^+\;and\;(Cs_6)4^+$.