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Effects of anatase-rutile phase transition and grain growth with WO3 on thermal stability for TiO2 SCR catalyst (WO3 첨가에 의한 TiO2계 SCR 촉매의 상전이 및 입자성장이 고온안정성에 미치는 영향)

  • Yoon, Sang-Hyeon;Kim, Jang-Hoon;Shin, Byeong-Kil;Park, Sam-Sik;Shin, Dong-Woo;Lee, Hee-Soo
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.21 no.4
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    • pp.181-186
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    • 2011
  • Thermal stability of the $TiO_2$ SCR catalyst with W03 loading was investigated in terms of structural and morphological analyses. The $TiO_2$ catalysts with 10 w% $WO_3$ content and without $WO_3$ were prepared. which were heat-treated at $800^{\circ}C$ for 5 h. It was found that the catalytic acidity was decreased by thermal degradation in the $WO_3-TiO_2$ specimen that relatively less than the $TiO_2$ specimen from FT-IR analysis. The phase transition of the $TiO_2$ catalyst from anatase to rutile was increased by heal-treatment, and the percentage of the rutile phase was 28.4 % in the $WO_3-TiO_2$ and 22.9 % in the $TiO_2$. A shell region of $WO_3$ distinguished from a $TiO_2$ particle was also observed in the grain boundary region, and the $WO_3$ led to the suppression of grain growth. It could be confirmed that the suppression of grain growth can contribute to the improvement of catalytic properties for thermal stability more than the increase of anatase-rutile phase transformation which cause the reduction of the catalytic activity in the $TiO_2$ SCR catalyst by the presence of $WO_3$.

Middle School Students' Construction of Physics Inquiry Problems and Variables Isolation and Clarification during Small Group Open-inquiry Activities (중학생의 소집단 자유탐구활동 중 물리 영역 탐구문제의 구성과 변인 추출 및 명료화 과정)

  • Yoo, Junehee;Kim, Jongsook
    • Journal of The Korean Association For Science Education
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    • v.32 no.5
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    • pp.903-927
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    • 2012
  • The study aimed to analyze middle school students construction of physics inquiry problems for open inquiry from the viewpoint of variable isolation and clarification, and investigate students' difficulties during the processes of variable isolation and clarification to get implications for teaching and learning strategies for small group open inquiry activities which have been included in the 2007 national curriculum. The participants were 4 students who had attended an outreach program for the science gifted run by a university institution located in Seoul area. They performed an open inquiry on egg drop for 13 lessons for 30 hours. Level descriptions for variable isolation and clarification have been developed and applied to analyze students' inquiry problems and variables included by the problems. Students iterated inquiry processed 5 times and the inquiry problem showed progress gradually. Dependent variables have been isolated ahead and the levels of variable isolation and clarification showed higher than the independent variables. Many kinds of independent variables isolated extensively and the independent variables and control variables have been mingled. One of the reasons why students had some difficulties in isolation of independent variables could be the absence of theoretical models. The realities of school lab could restrict the variable isolation and clarification as well as topic selections. Some sensory or extensive variables such as broken eggs and drop height seem to be salient to be focused on as core variables. Lack of background knowledges could be one of the reasons for students' difficulties in variable clarification, such as theoretical definitions and operational definitions. As a result of lacking background knowledges, students could not construct theoretical models even though they could isolate and clarify variables as scientific lexical definitions. Some perceptions of inquiry as trial and error or reckless establishment of causal relations between variables could be accounted as one reason.

Beach Resort Formation and Development Processes by Fabric Construction in an Island Environment (구조물 축조에 의한 도서지역 해수욕장의 발달과정에 관한 연구 -완도군 보길면 지역을 사례로-)

  • 박의준;황철수
    • Journal of the Korean Geographical Society
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    • v.36 no.4
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    • pp.474-482
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    • 2001
  • The purpose of this study is to investigate the formation and development processes of beach resort by fabric construction in a island environment. The results are as follows. (1) The research area(Tong-ri beach, Bokil-myon, Chollanam-do)has been transformed to belch by sedimentary environmental change since latter half of 1800's. (2) The mean slope of beach face is 0.96°, and the difference of attitude between beach and mud flat face is 75cm. (3) The mean particle size of beach surface sediment is 3.53$\Phi$. This value is very finer than that of any other beach in Korea peninsula. But its value is coarser than that of mud flat surface sediment. (4) The particle size distribution of core sediment is become changed to fine particle in 70cm depth. This value is corresponded to difference of altitude between beach face and mud flat face. (5) The analysis of aerial photographs after 1970 indicates that sedimentation process was not brisked since 1970's. Consequently, the research ares has been developed by sedimentary environmental change for sea-level rise effect and wave height energy rise effect.

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Differences of Perceptions between Pre-service and In-service Elementary School Teachers on the Prevention and Intervention of School Violence (학교폭력의 예방 및 대책에 관한 교대생과 초등교사의 인식 비교)

  • Song, Jae-Hong;Kim, Kwang-Soo;Park, Sung-Hee;Ahn, Ie-Hwan;Oh, Ik-Soo;Eun, Hyuk-Gi;Jeong, Jong-Jin;Cho, Bung-Hwan;Hong, Jong-Kwan;Hwang, Mae-Hyang
    • The Korean Journal of Elementary Counseling
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    • v.11 no.3
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    • pp.485-504
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    • 2012
  • The purpose of study was to analyze the differences of perceptions between pre-service and in-service elementary school teachers on the prevention and intervention of school violence. For this purpose, 459 student teachers and 289 in-service teachers has responded a questionnaire consisted of 12 core questions and 8 supplementary questions about the prevention and intervention of school violence. The findings of this study was as follows: First, in-service elementary school teachers perceived the problem of school violence more seriously than student teachers. Second, in-service elementary school teachers and student teachers perceived the lack of parents' concern of their children and the disturbed friendship as major causes to arouse school violence, and insisted to improve students' emotional self-control and social skills in order to prevent school violence. Third, in coping with students' violent behaviors they took the need to interview the student' parents and to invite them to meet each other halfway. Fourth, With government's comprehensive countermeasures against school violence they acknowledged the importance of policy alternatives but made doubt of their effectiveness. Finally, both in-service elementary school teachers and student teachers approved of a plan to assign the required subject of 'Prevention and Intervention of School Violence' to the student teachers, particularly student teachers approved more positively than in-service elementary school teachers.

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Spatial Characteristics of Cultural Economy Emergence and Diffusion: Creative Retail Shops in Bukchon (문화경제의 발현과 확산의 공간적 특징: 북촌의 창의적 소매업을 중심으로)

  • Lee, Kyung-Ok;Lee, Keum-Sook
    • Journal of the Economic Geographical Society of Korea
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    • v.9 no.1
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    • pp.23-38
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    • 2006
  • This study attempts to investigate the spatial characteristics of cultural economies of Bukchon in Seoul, where abundant cultural assets exist. This area has been the administrative-political core locale since 14C, therefore, a lot of traditional- and contemporary-cultural facilities are remains, This area possessed unique place characteristics by coexisting traditional and modern cultures, and thus attracted to culture demanders. Recently many economic activities have increased in this area, and most of them are related with the cultural elements of the region, In particular creative retail shops, which produce goods by flexible-specialized production system, have been agglomerated in this area, The goods are designed, produced, and sold at the shop place. Most of them are uniquely designed hand made products, and produced a few amount. The economic value of these products related with the cultural environment of Bukchon. These creative shops emerged at the front of Samcheongdong street in the beginning, and then have diffused into the inside of Samcheongdong street and Hwagae street. The shops have very unique exteriors related with traditional houses in this area, and located on roadsides where are not many passerby. Most owners of the retail stores are highly educated and studied design, and produce goods by themselves at the shops. The reason that they opened their shops in Bukchon is directly related with the unique cultural environment of this area. They hope that more unique and artistic stores join this area so that developed this area as culture and fashion combined area.

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Geochemistry of Heavy Metals and Rare Earth Elements in Core Sediments from the Korea Deep-Sea Environmental Study (KODES)-96 Area, Northeast Equatorial Pacific (한국심해환경연구(KODES) 지역 주상 퇴적물중 금속 및 희토류원소의 지구화학적 특성)

  • Jung, Hoi-Soo;Park, Sung-Hyun;Kim, Dong-Seon;Choi, Man-Sik;Lee, Kyeong-Young
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.2 no.2
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    • pp.125-137
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    • 1997
  • To study the vertical variation of heavy metal and Rare Earth Element (REE) contents in deep-sea sediments, eighteen cores were sampled from the Korea Deep-sea Environmental Study (KODES)-96 area in the C-C zone (Clarion-Clipperton fracture zone), northeast equatorial Pacific. Sediment columns can be divided into three units based on sediment colors and geochemical characters; uppermost Unit I with brown color, middle Unit II with pale brown color and smaller Ni/Cu ratio than the ratio in Unit I, and lowermost Unit III with dark (brown) colors and higher contents of Mn, Ni, Cu, and REEs than those in Unit I and II. Unit II can be divided more into two layers of upper Unit IIa and lower Unit IIb. Unit IIb is characterized by high contents of Cu, 3+REEs (REEs except Ce), smectite, and severely deteriorated fossil tests. Unit III can also be divided into two units; upper Unit IIIa with dark brown color, and lower Unit IIIb with black color and enriched Mn and Fe. The KODES area was located near from the East Pacific Rise (EPR) When Unit III Sediments were deposited, considering the hiatus between Unit II and III (Quaternary-Tertiary boundary) and the spreading rate (10 cm/yr) and direction (north southern west) of the Pacific plate from the EPR. High contents of Mn and Fe in Unit IIIb may be related with hydrothermal influence from the EPR. Meanwhile, Unit IIb (about 2~3 Ma) and Unit III (11~30 Ma) layers were probably formed near (or under) the equatorial high productivity zone, and accordingly received a lot of organic materials. As a result, Cu and 3+REEs, closely associated with organic materials, are enriched in smectite and/or Ca-P composites (fish bone debrise, biogenic apatite) after decomposition and reprecipitation on the sea floor. Higher contents of Cu and 3+REEs in Unit IIb and III are suggested to be the result of abundant supply of organic substances in the equatorial high productivity zone.

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The Effects of the Change of Operating Income Disclosure Policy under K-IFRS - Evidence from KOSDAQ Market - (K-IFRS 이후 영업이익 공시정책의 변화에 대한 연구 - 코스닥 시장을 중심으로 -)

  • Baek, Jeong-Han;Choi, Jong-Seo
    • Management & Information Systems Review
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    • v.33 no.3
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    • pp.167-187
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    • 2014
  • While Korean GAAP had detailed regulations for the measurement and disclosure of operating income in the past, K-IFRS did not provide specific rules for operating income until 2011. Some firms that adopted K-IFRS before 2011 did not disclose or calculated operating income in an inconsistent manner although operating income is usually considered as one of the core information items to assess firm valuation. Inconsistency in firms' treatment of operating income invoked much criticism from diverse users of financial statement. The Korean Accounting Institute (KAI hereafter) revised the K-IFRS rules relevant to operating income in September 2010 in response to the voices raised by the business community, whereby the operating income number is allowed to be calculated in conformity with the previous K-GAAP. This study was motivated by the revision of K-IFRS and aims to provide a clue on the validity of such policy decision. To achieve the research objective, we test the relative value relevance of the alternative operating income numbers under K-IFRS versus K-GAAP. Our main findings are as follows. The value relevance of operating income reported before K-IFRS is proved to be higher than after K-IFRS. K-IFRS operating income adjusted to the previous K-GAAP has greater explanatory power for market values relative to one calculated under the K-IFRS regime. In an additional analysis, the sample was decomposed according to whether the operating income under K-IFRS is greater than under K-GAAP. The difference in the value relevance of K-IFRS versus K-GAAP operating income is significant only in the subsample consisting of firms which reports higher operating income under K-IFRS compared to K-GAAP. Also, the firms which would have reported negative operating income on a consecutive basis are more likely to have chosen K-IFRS, resulting in higher numbers than otherwise. It is likely that firms facing the threat of delisting due to consecutive operating loss reporting are more likely to have adopted K-IFRS disclosure rules by which they could report higher operating income numbers. To sum up, these results corroborate the limitation inherent in the K-IFRS regarding operating income disclosures. This paper suggests that the recent revision of K-IFRS implemented by KAI is likely to mitigate some of afore-mentioned limitations effectively.

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창의성과 비판적 사고

  • Kim, Yeong Jeong
    • Korean Journal of Cognitive Science
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    • v.13 no.4
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    • pp.80-80
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    • 2002
  • The main thesis of this article is that the decisive point of creativity education is the cultivation of critical thinking capability. Although the narrow conception of creativity as divergent thinking is not subsumed under that of critical thinking, the role of divergent thinking is not so crucial in the science context of creative problem-solving. On the contrary, the broad conception of creativity as focusing on the reference to utility and the third conception of creativity as a process based on the variation and combination of existing pieces of information are crucial in creative problem-solving context, which are yet subsumed under that of critical thinking. The emphasis on critical thinking education is connected with the characteristics of contemporary knowledge-based society. This rapidly changing society requires situation-adaptive or situation-sensitive cognitive ability, whose core is critical thinking capability. Hence, the education of critical thinking is to be centered on the learning of blowing-how and procedural knowledge but not of knowing-that and declarative knowledge. Accordingly, the learning of critical thinking is to be headed towards the cultivation of competence but not just of performance. In conclusion, when a rational problem-solving through critical and logical thinking turns out consequently to be novel, we call it creative thinking. So, creativity is an emergent property based on critical and logical thinking.

창의성과 비판적 사고

  • 김영정
    • Korean Journal of Cognitive Science
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    • v.13 no.4
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    • pp.81-90
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    • 2002
  • The main thesis of this article is that the decisive point of creativity education is the cultivation of critical thinking capability. Although the narrow conception of creativity as divergent thinking is not subsumed under that of critical thinking, the role of divergent thinking is not so crucial in the science context of creative problem-solving. On the contrary, the broad conception of creativity as focusing on the reference to utility and the third conception of creativity as a process based on the variation and combination of existing pieces of information are crucial in creative problem-solving context, which are yet subsumed under that of critical thinking. The emphasis on critical thinking education is connected with the characteristics of contemporary knowledge-based society. This rapidly changing society requires situation-adaptive or situation-sensitive cognitive ability, whose core is critical thinking capability. Hence, the education of critical thinking is to be centered on the learning of blowing-how and procedural knowledge but not of knowing-that and declarative knowledge. Accordingly, the learning of critical thinking is to be headed towards the cultivation of competence but not just of performance. In conclusion, when a rational problem-solving through critical and logical thinking turns out consequently to be novel, we call it creative thinking. So, creativity is an emergent property based on critical and logical thinking.

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Rate of Sediment Accumulation and Geochemical Characteristics of Muddy Sediment in the Central Yellow Sea (황해 중앙부 해역 니질 퇴적물의 지화학적 특성 및 퇴적률)

  • 윤정수;김여상
    • The Korean Journal of Quaternary Research
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    • v.16 no.1
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    • pp.1-16
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    • 2002
  • A total of 4 muddy sediment samples collected from the Central Yellow Sea were analyzed for chemical composition. The results are compared with the previously published Huanghe, Changjiang and Keum River geochemical data in order to understand provenance and sedimentation of fine-grained mud, and the sediment accumulation rates estimated. The sandy sediment facies is distributed in the eastern area, a patch of fine-grained mud exists in the western central prat, and the sandy mud and clay sedimentary facies shot. north to south zonal distribution in the central region. The content of calcium carbonate ranges from 2.8 to 10.5%, and its distributional trends to be more concentrated on the western muddy sediments near toward the China side rather than on the eastern sandy sediments. The accumulation rates obtained using Pb-210 geochronologies for the muddy sediments in the Central Yellow Sea showed ranges from 0.21 to 0.68 cm/yr or 0.176 to 0.714 g/$\textrm{cm}^2$. yr. The sedimentation rate from core CY96010 located in the eastern near side of Shandong Peninsula which is affected by the Huanghe River shows 0.68 cm/yr or 0.714 g/$\textrm{cm}^2$ . yr. The sediment cores CY96008 and CY96002 in the Central Yellow Sea, the estimated of sediment accumulation rates shows 0.21~0.23cm1yr or 0.176~0.220 9/$\textrm{cm}^2$.Vr respectively, which are much lower than above samples. These indicate that the muddy sediments in central area of the Yellow Sea may have received influence of the sediment discharge from the Huanghe River. The concentrations of Ca, Na, Sr, Ho, La, Tb, Ta and Ca/Ti ratio of the muddy sediments in the Central Yellow Sea are higher than those of the Changjiang sediments and lower than those of the Huanghe sediments. However, these element values showed similar concentration patterns than those of the Huanghe sediment. The element contents such as Fe, Ti, Nl, Co, Cr, Cu, Pb, Sc, Ce, Nd, Sm, Eu, Cd and Dy in the study area are higher than those of the Huanghe sediments and lower than the Changjiang River sediments, but these values showed close to resemblance content trends those of the Changjiang sediment. The concentration of Mn, K and Sr in sediments of the study area are similar to those of the Keum River and eastern Yellow Sea sediment. They are rich in Zn, Rb, Cd, U, Cs and Li than those of the other comparison legions. Therefore, the terrigenous materials sources of the muddy sediment in the Central Yellow Sea comes mainly from Huanghe River in the past and present, and also have party derived from the Changjiang and Keum River, while the biological deposit in this area are carried by the Yellow Sea Warm Current.

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