• 제목/요약/키워드: second transition

검색결과 770건 처리시간 0.027초

연속고체 표면 위의 단순유체 홑층에 대한 시늉연구 (A Simulational Study of a Simple Fluid Monolayer on a Smooth Solid Surface)

  • 한규광
    • 자연과학논문집
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    • 제10권1호
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    • pp.1-7
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    • 1998
  • 대정준 몬테카를로 시늉을 집중적으로 수행하여 무결정 연속고체 표면 위에 흡착된 Lennard-Jones 유체의 홑층에 대해 덮힘률 $\theta$ ~ 0.8에서 1.8 까지를 연구하였다. 시늉 결과는 최근 흑연위의 알곤 홑층 녹기에 대한 열역학적 실험측정에서 관찰되어졌던 두 단계의 녹음 행태를 뚜렷이 보여 주었다. 본 연구에서 관찰된 녹음 행태는 갑작스러운 밀도 변화 후에 점진적인 상전이로 이루어진다. 홑층 구조에 대한 스냅 사진들은 녹기과정에 어긋나기 짝의 형성과 그 짝의 분리가 연루되어 있다는 것을 가르키고 있다. 계의 크기에 의한 효과를 감안하여, 갑작스러운 밀도 변화는 Kosterlitz, Thouless, Halperin, Nelson, and Young (KTHNY)의 이론과 무관할 것인 반면에, 두 번째의 점진적 전이는 KTHNY 타입의 녹기 상전이일 것이라고 사료된다.

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학교 학습환경 변화에 따른 학생적응에 관한 연구 - 신축 교과교실제 중학교로의 이전경험을 중심으로 - (A Study on Students' Adaptation to Changes in Their Learning Environments at School - Focused on Students' Experience of Transition to the New Variation Type Middle School -)

  • 이선영
    • 교육시설 논문지
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    • 제27권2호
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    • pp.79-86
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    • 2020
  • Since the introduction of the new Variation Type school, few studies have focused on students' adaptation to the changes in their learning environments at school. This paper is based on the Stage-Environment Fit theory, which asserts that a successful school life(in terms of motivation to learn) is ensured only when the school environment meets the social and emotional needs of students. Focusing on the third-grade student's adaptation to a new Variation Type school during their middle school period, the following conclusions were drawn. First, the transition to a new Variation Type school during middle school is much more difficult than adjusting to a new Variatio Type school upon admission to middle school. Second, this difficulty in adaptation is caused by socio-emotional dissatisfaction in adolescent students, for whom deconstruction of previous friendships can hinder motivation to learn. Third, third-grade students who experienced stress due to spatial changes tended to have a negative attitude towards the new Variation Type itself as they feel more tired from failing to use the space properly. Fourth, to transition successfully to a new Variation Type school, socio-emotional problems must be solved through the reduction of scale of the homebase, and the provision of various choices increasing the number of homebase.

Molecular Dynamics Simulation for Monolayers of Alkyl Thiol Molecules at Air-Solid Interfaces

  • 이송희;김한수
    • Bulletin of the Korean Chemical Society
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    • 제17권8호
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    • pp.700-706
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    • 1996
  • We present the results of molecular dynamics simulations of monolayers of long-chain alkyl thiol [S(CH2)15CH3] molecules on an air-solid interface using the extended collapsed atom model for the chain-molecule and a gold surface for the solid surface. Several molecular dynamics simulations have been performed on monolayers with areas per molecule ranging from 18.30 to 32.10 Å2/molecule. It is found that there exist three possible transitions: a continuous transition characterized by a change in molecular configuration without change in lattice structure, a sudden transition characterized by the distinct lattice defects and perfect islands, and a third transition characterized by the appearance of a random, liquid-like state. The analysis of probability distributions of the segments shows that the structure of the chain-molecules at the air-solid interface is completely different from that at the air-water interface in the view of the degree of overlap of the probability distributions of the neighbor segments. The calculated diffusion coefficients of the chain-molecules on the monolayers seem to be not directly related to any one of the three transitions. However, the large diffusion of the molecules enhanced by the increment of the area per molecule may induce the second transition.

경력단절 어린이집 보조교사의 경험과 의미연구 (A Study on the Experiences of Daycare Center Assistant Teachers Taking a Career Break)

  • 최현정;정연아
    • 한국보육지원학회지
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    • 제17권4호
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    • pp.49-71
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    • 2021
  • Objective: This study aims to explore the experiences of women who take a career break while working in daycare center as a teacher assistant. Methods: Seven assistant teachers and two child care teachers who took more than two years of career break were selected and given in-depth interviews over 17 weeks from August to December in 2020. Results: The results of this study are as follows. First, the women experienced the need for a career transition as an assistant teacher because it was time to for a change. Second, while working as a teacher assistant, they had various experiences and meanings in the process of career transition while playing the role as a teacher in daycare centers. Third, they also had some difficulties in conflict and some needs to build their professional expertise as a teacher. Conclusion/Implications: The study is expected to give insights to understand the difficulties of teachers who had experienced the need for a career transition as teacher assistant and to provide important data to develop teacher professional development.

오리피스와 충돌하는 액적 거동에 관한 연구 (A Study on the Droplet Behavior Impacting on an Orifice)

  • 서동현;이덕진;이현빈;강보선
    • 한국분무공학회지
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    • 제27권4호
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    • pp.188-194
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    • 2022
  • In this study, the behavior of water droplet impacting on a thin horizontal orifice was investigated. The impact behavior modes, transition velocities and diameters of daughter droplets were analyzed by changing the droplet velocity, orifice diameter and orifice thickness. Four typical modes of impacting droplet on an orifice were observed. The single-droplet and double-droplet transition velocities increased with increasing the orifice thickness and decreased with increasing the orifice diameter. On the other hand, the multi-droplet transition velocity decreased and then increased as the orifice diameter increased. At thin orifice thickness, the single droplet diameter approximated the orifice diameter, and increasing the orifice thickness produced a droplet larger than the orifice diameter. In the case of double droplet mode, the diameter of the first droplet showed a similar tendency like the single droplet mode, but the diameter of the second droplet was smaller than that of the first droplet, and the difference between them was affected more by the orifice thickness.

제2차 MLMS 알고리즘을 이용한 시스템 Identification (System Identification Using the Second Order MLMS Algorithm)

  • 김해정;이두수
    • 전자공학회논문지B
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    • 제29B권11호
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    • pp.8-15
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    • 1992
  • This paper analyzes the properties of such algorithm that corresponds to the LMS algorithm with additional update terms, parameterized by the scalar factors $\alpha$ and $\beta$, and presents its structure. The analysis of convergence leads to complex eigenvalues of the transition matrix for the mean weight vector. Regions in which the algorithm becomes stable are demonstrated. The computational cmomplexities of MLMS algorithms are compared with those of MADF, sign and the conventional LMS algorithms. In application of the system identification the second order momentum MLMS algorithm has faster convergence speed than LMS and the first order MLMS algorithms.

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SECOND CHERN NUMBERS OF VECTOR BUNDLES AND HIGHER ADELES

  • Osipov, Denis V.
    • 대한수학회보
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    • 제54권5호
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    • pp.1699-1718
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    • 2017
  • We give a construction of the second Chern number of a vector bundle over a smooth projective surface by means of adelic transition matrices for the vector bundle. The construction does not use an algebraic K-theory and depends on the canonical ${\mathbb{Z}}-torsor$ of a locally linearly compact k-vector space. Analogs of certain auxiliary results for the case of an arithmetic surface are also discussed.

히르슈슈프룽병의 One-stage Transanal Endorectal Pull-through 술식에서 대장조영술의 의의 (Significance of Contrast Enema in One-stage Transanal Endorectal Pull-through Operation for Hirschsprung Disease)

  • 신만식;이미정;김명준;홍영주;장혜경;한석주;오정탁
    • Advances in pediatric surgery
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    • 제18권2호
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    • pp.75-82
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    • 2012
  • In one-stage transanal endorectal pull-through operation (TERPT) for Hirschsprung disease, preoperative evaluation by contrast enema (CE) is important tool in aspect of planning of surgical procedure as well as diagnosis. This study was to evaluate the significance of CE for identifying the extent of aganglionic bowel. A retrospective analysis was performed in 40 patients who underwent TERPT between 2003 and 2011. The authors reviewed the CE studies and their correlation with pathologic extent of aganglionosis. Total 66 contrast enemas were performed in 40 patients. Twenty patients underwent single CE, but 20 patients required multiple CEs. In single CE group, 17 had clear radiographic transition zone, but 3 had less definite transition zone. In multiple CE group, 17 patients who had equivocal finding in first or second CE had definite radiographic transition zone, but 3 patients of this group had less definite radiographic transition zones. Overall, 34 patients (85%)had clear radiographic transition zone by single or repeated CE. One (2.9%) out of 34 patients with clear radiographic transition zone had discordance between radiographic and pathologic transition zone. In contrast 4 (66.7%) out of 6 patients with equivocal radiographic transition zone had discordance between radiographic and pathologic transition zone. Observation of clear radiographic transition zone is important in preparation of TERPT, and repeated CE is helpful to reduce the discordance between radiographic and pathologic transition zone. Awareness of the possibility of discordance is also important if radiographic transitional zone is not clear.

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기업사옥 저층부의 공공성을 위한 계획특성 경향 분석 (Analysis of Trend on the Planning Characteristics for Publicity of the Low Level Area in the Headquarter Office Buildings)

  • 강선경;송병준;주범
    • 한국실내디자인학회논문집
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    • 제23권6호
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    • pp.178-186
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    • 2014
  • Recently, a lower levels space has turned into a mediating space where people can experience urban spaces directly and it has revitalized communication between the city and company and also it has changed itself newly. In addition, this space which is connecting interior and exterior spaces of company's buildings can attract people living in the downtown as shock-absorbing and transitional space and it is getting more important part in urban context these days. Through case studies of corporate office space planning characteristics derived lower levels and to provide direction for the lower levels of the corporate office space planning purposes of the present study. Therefore, I establish the concept of the public good corporate office space and transition space, the concept of transition through the first Theoretical Methods. I investigate the properties of the transition area is used as the target for completion of the current construction culture destination since 2000, winning the corporate office, I have been talking about the characteristics of the corporate office along the lower part of the last PPS assessment criteria to apply to the building. PPS by applying an assessment factor can be derived for building enterprise case studies and analysis of the results the following conclusions about the use of publicity and transition space. First, lower levels of corporate office space had been applied to the use and activity in a very important project characteristics. Second, corporate office space, lower levels of access and linkages are important. Finally, in terms of public characteristics transition space is a important characteristic for low-rise space of headquarter buildings.

Conformational Transition of Form II to Form Ⅰ PoLy(L-proline) and the Aggregation of Form Ⅰ in the Transition: Water-Propanol Solvent System

  • 김현돈
    • Bulletin of the Korean Chemical Society
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    • 제18권9호
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    • pp.922-928
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    • 1997
  • The conformational transition of poly(L-proline) (PLP), Form Ⅱ → Form Ⅰ and the intermolecular aggregation of the product, Form Ⅰ, during and after the transition in water-propanol (1:7, 1:9, 1:15.7, and 1:29 v/v) were studied. For the study, the viscosity change and excess light scattering intensity were measured in the course of the transition which was determined by the Form Ⅰ fraction, fI of the sample solution. For the PLP sample of molecular weight Mv=31,000 the experimental results show that the reaction course is roughly divided into three regions: in the first region [fI=0.27 to 0.40 (- [α]D=400 to 330)], the conformational change of Form Ⅱ → Form Ⅰ occurs with decrease of viscosity, in the second region [fI=0.40 to 0.80 (- [α]D=330 to 120)], a partial side-by-side (p-S-S) type aggregation in which Form Ⅰ blocks interact with each other, which induces the increase of viscosity, starts to occur, and in the third region [fI=0.80 to 1.00 (- [α]D=120 to 15)], a side-by-side type (raft like) aggregation of Form Ⅰ or an end-to-end (E-E) type aggregation occurs according to the solvent situation, i.e., in a water-rich medium [water-propanol (1:9 or 1:7 v/v)], the (S-S) type aggregation with a gross decrease in viscosity occurs while in a water-poor medium [water-propanol (1:29 or 1:15.7 v/v), the (E-E) type aggregation with a large increase in viscosity occurs. The (S-S) type aggregation was promoted at high temperatures. Based on the structure of PLP, a reasonable mechanism for the (p-S-S) and (S-S) aggregation which occurs with the transition of Form Ⅱ → Form Ⅰ is considered. The suggested mechanism was also supported by the result of chain length effect of PLP for the aggregation.