• 제목/요약/키워드: Homogeneous group

검색결과 396건 처리시간 0.026초

교육시설의 공간구성과 이용방법에 관한 연구 -일본과 미국의 1970년대 이후의 초등학교의 사례를 중심으로- (A Study on the Space Composition and Usage of Educational Facilities -Focused on Japan and U.S. Elementary School after 1970's-)

  • 김진모;임수영
    • 교육시설
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    • 제14권1호
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    • pp.44-51
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    • 2007
  • The purpose of this research starts analyzing the case with the United States and Japan and considering the plan form of educational facilities in the advanced country for the improvement of educational facilities in our counties. Japan was managing the educational system which carried out homogeneous till the first stage of the 1970s like advanced nations, such as the educational system of the industrialization age before World War II, i.e., Britain and the United States. The form of an American open school was adopted after the second half of the 1960s, trying the educational system which also globalized the educational system of Japan while the world went into the information society. In the process of the introduction, Japan did not simply imitate a huge open space in the United States. Japan selected the content of the education carefully. And, to do an original educational activity by guidance. The current classroom and multipurpose space were planned as one body. As a result, the environment of the classroom was able to do various studying patterns of individual study and the group study.

Physico-Chemical Properties of Pseudoceramide in Relation to Bilayer-Forming

  • Jeong, Min-Woo;Oh, Seong-Geun;Kim, Do-Hoon;Kang, Hak-Hee
    • 대한화장품학회지
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    • 제27권1호
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    • pp.3-15
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    • 2001
  • The bilayer forming ability of pseudo-ceramide PC104 in octanoic acid/water/n-octyl $\beta$-D-glucoside mixtures was investigated through the phase diagram. Because of its low solubility in water and of its crystallization, pseudoceramide PC104 was dissolved in octanoic acid, which is nontoxic additive for foods and cosmetics. The mixtures formed four different phases (L1, L2, LC and two phases). Depending on the concentration of PC104 in octanoic acid, the region of each phase was extended or contracted. On the contrary to the region of L2, regions of lamellar phase and L1 phase were expanded. The bilayer-forming ability of PC104 was explained on the basis of concentration of PC104 at interface and interaction between PC104 and octanoic acid. From FT-IR results, it was found that the interactions of PC104’s polar head group with octanoic acid increased as the amount of PC104 in octanoic acid increased. Also emulsion size and size distribution have been studied depending upon the emulsification path. droplets of emulsion prepared from lamellar phase were smaller and more homogeneous compared to those of emulsions formed from L2 phase.

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A New Cluster Head Selection Technique based on Remaining Energy of Each Node for Energy Efficiency in WSN

  • Subedi, Sagun;Lee, Sang-Il;Lee, Jae-Hee
    • International journal of advanced smart convergence
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    • 제9권2호
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    • pp.185-194
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    • 2020
  • Designing of a hierarchical clustering algorithm is one of the numerous approaches to minimize the energy consumption of the Wireless Sensor Networks (WSNs). In this paper, a homogeneous and randomly deployed sensor nodes is considered. These sensors are energy constrained elements. The nominal selection of the Cluster Head (CH) which falls under the clustering part of the network protocol is studied and compared to Low Energy Adaptive Clustering Hierarchy (LEACH) protocol. CHs in this proposed process is the function of total remaining energy of each node as well as total average energy of the whole arrangement. The algorithm considers initial energy, optimum value of cluster heads to elect the next group of cluster heads for the network as well as residual energy. Total remaining energy of each node is compared to total average energy of the system and if the result is positive, these nodes are eligible to become CH in the very next round. Analysis and numerical simulations quantify the efficiency and Average Energy Ratio (AER) of the proposed system.

Zn-Ion Coated Structural $SiO_2$ Filled LDPE: Effects of Epoxy Resin Encapsulation

  • Reddy C. S.;Das C. K.;Agarwal K.;Mathur G N.
    • Macromolecular Research
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    • 제13권3호
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    • pp.223-228
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    • 2005
  • In the present work, a low-density polyethylene (LDPE) composite, filled with Zn-ion coated structural silica encapsulated with the diglycidyl ether of bisphenol-A (DGEBA), was synthesized using the conventional melt-blending technique in a sigma internal mixer. The catalytic activity of the Zn-ions (originating from the structural silica) towards the oxirane group (diglycidyl ether of bisphenol-A (DGEBA): encapsulating agent) was assessed by infrared spectroscopy. Two composites, each with a filler content of $2.5 wt\%$ were developed. The first one was obtained by melt blending the Zn-ion coated structural silica with LDPE in a co-rotating sigma internal mixer. The second one was obtained by melt blending the same LDPE, but with DGEBA encapsulated Zn-ion coated structural silica. Epoxy resin encapsulation of the Zn-ion coated structural silica resulted in its having good interfacial adhesion and a homogeneous dispersion in the polymer matrix. Furthermore, the encapsulation of epoxy resin over the Zn-ion coated structural silica showed improvements in both the mechanical and thermal properties, viz. a $33\%$ increase in the elastic modulus and a rise in the onset degradation temperature from 355 to $371^{\circ}C$, in comparison to the Zn-ion coated structural silica.

The Demographic Faultline Is a New Situational Factor for Team Management: The Effect of Leader Teamwork Behaviors on Support for Innovation

  • Na, Dong Man;Park, Seong Hoon;Kwak, Won Jun
    • The Journal of Asian Finance, Economics and Business
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    • 제5권4호
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    • pp.149-160
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    • 2018
  • An alternative method for team diversity studies is to examine demographic faultlines. A concept of demographic faultline enables us to better understand team dynamics with multidimensional diversity. This study suggests the demographic faultline as a new situational factorto influence the relationship between leader teamwork behaviors and a climate of support for innovation. When subgroups divided by demographic faultline are homogeneous within them and heterogeneous between them, the homogeneity may increase intimacy in each subgroup while the heterogeneity may increase exclusiveness between those subgroups. We argued that a leader could play an important role to build a cooperative relationship between faultline-based subgroups and highlight positive aspects of developing and maintaining subgroups in organizations. With a sample of 81 teams (558 employees), it was examined how leader teamwork behaviors would affect a team-level climate of support for innovation and how this relationship would be moderated by each team's demographic faultline (gender, age, and educational specialty). As predicted, it was found that there was a significant positive relationship between each leader's teamwork behaviors and each team's climate of support for innovation. In addition, this relationship was stronger for teams with strong faultline than with weak faultline. Our findings and their implications were further discussed.

黃砂의 量的推定을 위한 基礎硏究 (Basic Research on the Quantitative Estimation of Yellow Sand)

  • 김동술
    • 한국대기환경학회지
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    • 제6권1호
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    • pp.11-21
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    • 1990
  • To quantitatively estimate the effect of yellow sand(loess) fromt he Northern China, various soil sources having similar chemical compositions to yellow sands should be separated and identified. After that, mass contribution for yellow sand can be calculated. The study showed that it was impossible to solve this problem by the traditional bulk analyses. However, particle-by-particle analysis by a CCSEM (computer controlled scanning electron microscope) gave enormous potentials to solve it. To perform this study, seven soil source data analyzed by CCSEM were obtained from Texas, U.S.A. Initially, each soil date was classified into two groups, coarse and fine particle groups since the particle number distribution showed a minimum occurring at 5.2$\mu$m of aerodynamic diameter. Particles in each group were then classified into one of the 283 homogeneous particle classes by the universal classification rule which had been built by an expert system in the early study. Further, mass fractions and their uncertainties for each class in each source were calculated by the Jackknife method, and then source profile matrix for the 7 soil sources was created. To use the profile matrix in the study of source contribution, it is necessary to test the degree of collinearity among sources. The profiles were tested by the singular value decomposition method. As a result, each soil source characterized by artificially created variables was totally independent each other and is ready to use in source contribution studies as a receptor model.

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Phylogenetic rind Taxonomic Status of the Phytoplasmas Associated with Water Dropwort (Oenanthe javanica DC) Disease in Korea and Japan

  • Jung, Hee-Young;Woo, Tae-Ha;Hibi, Tadaaki;Namba, Shigetou;Lee, Joon-Tak
    • The Plant Pathology Journal
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    • 제18권3호
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    • pp.109-114
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    • 2002
  • To evaluate the phylogenetic and taxonomic status of the phytoplasmas associated with water dropwort (Oenanthe javanica DC) disease in Korea and Japan, their 16S rDNA was analyzed. DNAs extracted from water dropworts collected in Korea (Kyongnam province) and Japan (Chiba prefecture) affected by witches' broom and yellows were subjected to PCR using phytoplasma-specific primers, which amplified a 1.4-kbp fragment that included the 16S rDNA. Phytoplasmas were characterized by RFLP analysis using AluI, HaeIII, HhaI, KpnI, MseI, and RsaI restriction enzymes and by sequence analysis of the PCR products. The mater dropwort witches'broom (WDWB) and water dropwort yellows (WDY) 16S rDNA sequences were identical and closely related to onion yellows (OY, 99.9% identity), which belong to the aster yellows (AY) 16S-subgroup. However, the KpnI RFLP analyses clearly distinguished the WDY and WDWB phytoplasmas from the OY phytoplasma. The phylogenetic analysis based on 16S rDNA showed that WDWE and WDY phytoplasmas are members of a relatively homogeneous group that evolved from a common ancestor.

Characteristics of Lanthanum Silicates Electrolyte for Solid Oxide Fuel Cells

  • Lee, Dong-Jin;Lee, Sung-Gap;Noh, Hyun-Ji;Jo, Ye-Won
    • Transactions on Electrical and Electronic Materials
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    • 제16권4호
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    • pp.194-197
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    • 2015
  • La9.33(Si5V1)O26 ceramics were fabricated by the mixed oxide method for solid oxide electrolytes. La9.33(Si5V1)O26 specimens showed the hexagonal, space group P63 or P63/m, and the unit cell volume increased when the sintering temperature increased. The specimen sintered at 1,400℃ showed the X-ray patterns of the homogeneous apatite single phase without the second phase, such as La2SiO5 and SiO2. The specimen sintered at 1,400℃ showed the maximum sintered density of 4.93 g/cm3. When the sintering temperature increased, the electrical conductivities increased, the activation energy decreased and the values were 7.83×10−4 S/cm, 1.61 eV at 600℃, respectively.

유성볼밀링 및 스파크 플라즈마 소결법으로 제조한 Mo-5~20 wt%. Cu 합금의 열적 특성 (Thermal Property of Mo-5~20 wt%. Cu Alloys Synthesized by Planetary Ball Milling and Spark Plasma Sintering Method)

  • 이한찬;문경일;신백균
    • 한국전기전자재료학회논문지
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    • 제29권8호
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    • pp.516-521
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    • 2016
  • Mo-Cu alloys have been widely used for heat sink materials, vacuum technology, automobile, and many other applications due to their excellent physical and electric properties. Especially, Mo-Cu composites with 5 ~ 20 wt.% copper are widely used for the heavy duty service contacts due to their excellent properties like low coefficient of thermal expansion, wear resistance, high temperature strength, and prominent electrical and thermal conductivity. In most of the applications, highly-dense Mo-Cu materials with homogeneous microstructure are required for better performance. In this study, Mo-Cu alloys were prepared by PBM (planetary ball milling) and SPS (spark plasma sintering). The effect of Cu with contents of 5~20 wt.% on the microstructure and thermal properties of Mo-Cu alloys was investigated.

Ferromagnetism and p-type Conductivity in Laser-deposited (Zn,Mn)O Thin Films Codoped by Mg and P

  • Kim, Hyo-Jin;Kim, Hyoun-Soo;Kim, Do-Jin;Ihm, Young-Eon;Choo, Woong-Kil;Hwang, Chan-Yong
    • Journal of Magnetics
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    • 제12권4호
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    • pp.144-148
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    • 2007
  • We report on the observation of p-type conductivity and ferromagnetism in diluted magnetic semiconductor $(Zn_{0.97}Mg_{0.01}Mn_{0.02})O:P$ films grown on $SiO_2/Si$ substrates by pulsed laser deposition. The p-type conduction with hole concentration over $10^{18}cm^{-3}$ is obtained by codoping of Mg and P followed by rapid thermal annealing in an $O_2$ atmosphere. Structural and compositional analyses for the p-type $(Zn_{0.97}Mg_{0.01}Mn_{0.02})O:P$ films annealed at $800^{\circ}C$ indicates that highly c-axis oriented homogeneous films were grown without any detectable formation of secondary phases. The films were found to be transparent in the visible range. The magnetic measurements clearly revealed an enhancement of room temperature ferromagnetism by p-type doping.