• Proceedings of the Korean Ceranic Society Conference
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• 2003.10a
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• pp.106.2-106
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• 2003

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.790-793
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• 2004

이중의 망간 perovskite 블록을 가진 Ruddlesden-Popper 상(R-P phase) $Sr_3Mn_2O_7$ 은 공기중에서 불안정하다. 본 연구에서는 망간 이온 자리에 철 이온을 소량 치환 함으로써 R-P 상을 안정화 시켰으며 이들의 결정구조는 X-선회절 데이터를 이용하여 Rietveld 법으로 정밀화하였다. 안정화에 필요한 Fe 이온의 양은 약 x=0.15로 나타났으며 Fe이온의 양이 증가함에 따라 쉽게 안정화 되었다. 자화율 측정결과 x=0.20 시료는 120K에서 paramgnetic-antiferromagnetic 전이를 나타내었고 이 전이 온도는 치환되는 Fe이온의 양이 증가함에 따라 감소하는 경향을 나타내었다.

• Journal of Information Management
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• v.16 no.4
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• pp.96-116
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• 1983

여타 다른 학문분야에서 주장되지 않는 정보과학(情報科學)에 대한 정립(定立)은 Kari Popper의 제 3 세계 - 객관적(客觀的) 지식(知識)의 세계(世界) - 고도(高度)의 자율성(自律性)을 인정함으로써 발견 될 수 있다는 것을 우선적으로 논의하게 된다. 따라서 정보과학의 임무란 객관적(客觀的) 지식(知識)의 세계(世界)를 탐구(探究)하는 것으로 정의(定議)를 내릴 수 있으며, 또한 도큐멘테이션과 도서관학의 영역을 확대시키는 것도 되지만, 양자(兩者)는 분명히 구별되어야 한다. Popper 식(式)의 존재론은 정보(情報) 개념(槪念) 및 주관적(主觀的) 객관적(客觀的) 지식(知識)들과의 관계가 확대되어 수용되어져야 한다. 그리하여 Popper의 세가지 세계의 공간영역들은 고찰(考察)의 대상이 된다. 인식과 물리적인 공간은 동일(同一)하지 않으며, 이러한 동일성(同一性)의 결여가 정보현상에 대한 적절한 정량화(定量化)를 저지시키는 문제를 발생케하는 요인이 된다고 주장하고 있다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.351-352
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• 2009

이중의 망간 페로브스카이트 블록을 가진 Ruddlesden-Popper 상 (R-P phase) $Sr_3Mn_2O_7$은 공기중에서 불안정하다. 본 연구에서는 Sr이온 자리에 La, Ca이온을 치환함으로써 R-P상을 안정화 시켰으며, 이들의 결정구조는 Neutron Diffraction 데이터를 이용하여 Rietveld 법으로 정밀화하였다 $La_{1.4}Sr_{0.8}Ca_{0.8}Mn_2O_7$, $La_{1.2}Sr_{0.9}Ca_{0.9}Mn_2O_7$은 $T_N$이 80K이며 25K에서 spin-glass 변이가 관찰되었다.

• Coupled systems mechanics
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• v.6 no.1
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• pp.29-40
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• 2017

This work employed density functional theory to investigate the structural and ferroelectric properties of the Ruddlesden-Popper (RP) phase of lead titanate, $Pb_2TiO_4$, as well as its phase transitions with epitaxial strain. A wealth of novel structural instabilities, which are absent in the host $PbTiO_3$ material, were identified in the RP phase through phonon soft-mode analysis. Our calculations showed that the ground state of $Pb_2TiO_4$ is antiferroelectric, distinct from the dominant ferroelectric phase in the corresponding host material. In addition, applied epitaxial strain was found to play a key role in the interactions among the instabilities. The induction of a sequence of antiferroelectric and antiferrodistortive (AFD) phase transitions by epitaxial strain was demonstrated, in which the ferroic instability and AFD distortion were cooperative rather than competitive, as is the case in the host $PbTiO_3$. The RP phase in conjunction with strain engineering thus represents a new approach to creating ferroic orders and modifying the interplay among structural instabilities in the same constituent materials, enabling us to tailor the functionality of perovskite oxides for novel device applications.

• Korean Journal of Logic
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• v.8 no.1
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• pp.23-46
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• 2005

The purpose of the paper Is to discuss and estimate early Popper's theory of probability, which is presented in his book, The Logic of of Scientific Discovery. For this, Von Mises' frequency theory shall be discussed in detail, which is regarded as the most systematic and sophisticated frequency theory among others. Von Mises developed his theory to response to various critical questions such as how finite and empirical collectives can be represented in terms of infinite and mathematical collectives, and how the axiom of randomness can be mathematically formulated. But his theory still has another difficulty, which is concerned with the inconsistency between the axiom of convergence and the axiom of randomness. Defending the objective theory of probability, Popper tries to present his own frequency theory, solving the difficulty. He suggests that the axiom of convergence be given up and that the axiom of randomness be modified to solve Von Mises' problem. That is, Popper introduces the notion of ordinal selection and neighborhood selection to modify the axiom of randomness. He then shows that Bernoulli's theorem is derived from the modified axiom. Consequently, it can be said that Popper solves the problem of inconsistency which is regarded as crucial to Von Mises' theory. However, Popper's suggestion has not drawn much attention. I think it is because his theory seems anti-intuitive in the sense that it gives up the axiom of convergence which is the basis of the frequency theory So for more persuasive frequency theory, it is necessary to formulate the axiom of randomness to be consistent with the axiom of convergence.

• Journal of The Korean Association For Science Education
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• v.20 no.1
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• pp.88-100
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• 2000

This study was to investigate high school students' philosophical views on science and positions of constructivists; Popper, Lakatos, Toulmin, and Kuhn. The results of this study were as follows: First, most students had the eclectic position(69%): similar percentages in sex(male 67%, female 75%), stream(liberal art 72%, science 74%), and of having experience on reading books or magazines related to the philosophy of science(ever 78%, never 64%). Second, in analysis of ANDVA of science philosphical perspectives by experience of reading books, magazines, and matters related to the philosophy of science, significant difference was revealed(p<.01). Students who had ever heard of or read about the philosophy of science were tend to have Empiricism. Third, ANDVA analysis of constructivist philosphical perspectives showed that male students were nearer to Kuhn's position than female(p<.05) and students in science stream were closer to Popper than in liberal art(p<.05). And male students in science party showed a great tendency to consent Popper's perspective(p<.01). This result seems to suggest that male students tended to think social aspects more deeply than female and held Kuhn's position.

• Journal of The Korean Association For Science Education
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• v.17 no.2
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• pp.209-224
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• 1997

In this study, the images of science education illustrated in the books written by six major modern philosophers of science (K. R. Popper, N. R. Hanson, T. S. Kuhn, I. Lakatos, P. Feyerabend and J. Ziman) were investigated. In this article, the parts, from the books investigated, which have direct relevance to science education are quoted and the discussions by the researchers on them are added. Particularly, the learning by trial and error (of Popper), the role of context in scientific thinking (of Hanson), science education through the history of science (of Lakatos), science education appreciating individualities and voluntary curiosity (of Feyerabend) and the social aspect of science as a source of its rationality (of Ziman) appear to be the main points which have direct relevances and meaningful implications to science education but which have not been considered or discussed in detail in science education.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.23 no.1
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• pp.14-19
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• 2013

We have successfully synthesized $Bi_{4-x}La_xTi_3O_{12}$ (x~2) having Aurivillius-type layered perovskite structure from exfoliated layered perovskite oxide of $K_2La_2Ti_3O_{10}$ with Ruddlesden-Popper structure. The reaction between the exfoliated lanthanum titanate nanosheets and BiOCl nanocrystal resulted in the formation of polycrystalline $Bi_{4-x}La_xTi_3O_{12}$ (x~2) after heating above $700^{\circ}C$. Colloidal suspension of the nanosheets could be obtained by intercalating ethylamine (EA) into the protonated lanthanum titanate, $H_2La_2Ti_3O_{10}$, derived from $K_2La_2Ti_3O_{10}$. Transmission electron microscopic (TEM) analysis show that the exfoliated lanthanium titanate nanosheets have a thickness of a few nano meters. According to X-ray diffraction (XRD) analysis, the exfoliated lanthanium titanate was found to be transformed into $Bi_{4-x}La_xTi_3O_{12}$ (x~2) after restacking with BiOCl and subsequent thermal treatment at > $700^{\circ}C$.

• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2761-2764
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• 2011

A new Ruddlesden-Popper phase $NdSr_2MnCrO_7$ has been prepared by the standard ceramic method. The powder X-ray diffraction studies suggest that the phase crystallizes with tetragonal unit cell in the space group I4/mmm. The electrical transport properties show that the phase is an electrical insulator and the electrical conduction in the phase occurs by a 3D variable range hopping mechanism. The magnetic studies suggest that the ferromagnetic interactions are dominant.