• 대한수학교육학회지:수학교육학연구
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• 제25권2호
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• pp.189-206
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• 2015

비례 추론에 관한 여러 연구에서 학습 지도 개선 방향으로 시각적 표상의 활용이 제안되어 왔다. 그러나 초등학교 교과서의 비와 비율, 비례식과 비례배분 단원에 사용되고 있는 시각적 표상은 질적인 면에서나 양적인 면에서나 매우 제한되어 있다. 이 논문에서는 교과서의 비례식과 비례배분 내용을 시각적 표상에 주목하여 분석하고, 시각적 표상의 적극적인 활용 방안 마련을 위한 기초적 논의를 전개한다. 이중수직선 모델과 이중테이프 모델은 각각 다중 묶음 관점과 변동 부분 관점에서 비례 맥락에 내재된 공변 관계와 불변성을 인식하는 데 유용하게 사용될 수 있다. 이 논문에서는 이를 초등학교 교과서의 비례식 및 비례배분 실생활 문제의 유형별로 이중수직선 모델과 이중테이프 모델이 어떻게 기능할 수 있는지를 논의함으로써 예시하였다. 초등 수학 교과서의 비례식 및 비례배분 실생활 문제의 각 유형은 두 관점(다중 묶음 관점과 변동 부분 관점) 및 두 모델(이중수직선 모델과 이중테이프 모델)과 모두 연결될 수 있다. 이 논문의 분석은 비례식과 비례배분 교재 구성 및 수업에서 시각적 표상을 활용하는 구체적인 방안을 마련하는 데 도움이 될 것이다.

• 멤브레인
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• 제12권1호
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• pp.41-50
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• 2002

하전된 마이크로채널의 전기이중층에서 계면동전기 흐름에 의해 발생되는 흐름전위는 일반적 Helmholtz-Smoluchowski 관계식으로부터 중공사 멤브레인 기공의 제타전위를 결정하는데 적용된다. 흐름전위는 실제 운전상황이나 물리화학적 조건에서의 표면특성 및 기공과 입자간 상호작용에 대한 유용한 실시간 정보를 제공함이 알려져 있다. 무리화학적 인자들이 주공사에 의한 여과에 미치는 영향을 투과플럭스와 흐름전위의 동시적 모니터링으로 고찰하였다. 특히, 본 연구에서는 중공사의 위치에 따른 흐름전위를 측정함으로써 중공사 길이 방향과 멤부레인 오염 진행에 따라 달라지는 케이크층 효과를 규명하는 실험방법을 다루었다. 실험결과, 입자농도가 증가할수록 투과플럭스는 감소하나 흐름전위는 증가하였다. 입자농도가 증가하면서 케이크층 성장은 활발하지만 쌓인 하전 입자들의 표면전하 효과로 흐름전위는 증가한 것이다. 용액의 이온화 세기를 KCI 0.1 mM에서 10mM로 증가하면 투과플럭스와 흐름전위가 함께 감소하였다. 이는, 이온화 세기의 증가로 라텍스입자 주위의 Debye 길이 감소로 치밀한 케이크층이 형성되고, 전기이중층의 얇아진 확산층에 의한 이온흐름의 약화로 흐름전위는 감소한 것을 판단된다.

• Advances in nano research
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• 제10권4호
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• pp.373-383
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• 2021

In this work, silver nitrate complexes of sulfanilamide-5-methyl-2-thiophene carboxaldehyde (SMTCA) ligand intercalated Zn/Al-layered double hydroxide [Ag-SMTCA-LDH] were synthesized for the potential application as an antimicrobial system. The SMTCA ligand was synthesized by reacting sulfanilamide and 5-methyl-2-thiophene carboxaldehyde in methanol and further complexation with silver nitrate metal ions [Ag-SMTCA]. The structural analyses of synthesized compounds confirmed an intercalation of Ag-SMTCA into Zn/Al-NO₃-LDH by flake/restacking method. SMTCA, Ag-SMTCA and Ag-SMTCA-LDH were characterized by ¹H nuclear magnetic resonance (¹H NMR) spectroscopy, Fourier-transform infrared (FTIR), ultraviolet-visible (UV-Vis) spectrophotometer, scanning electron microscopy (SEM) and transmission electron microscopy (TEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). It was found that Ag-SMTCA-LDH exhibited good antimicrobial activity against both gram-positive (Bacillus subtilis, [B. subtilis], Staphylococcus aures, [S. aureus]) and gram-negative (Escherichia coli, [E. coli], Pseudomonas aeruginosa [P. aeroginosa]) bacteria as well as excellent antioxidant activity.

• Asia Marketing Journal
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• 제15권1호
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• pp.57-81
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• 2013

The purpose of this paper is to seek ways to improve the competitiveness of Korea's fashion industry by utilizing the source of competitiveness of Japan's fashion industry, which represents the world's leading countries in terms of fashion, so that Korea can better enter the global fashion market. The study shall first compare the competitiveness of the Japanese and Korean fashion industries by utilizing the generalized double diamond model; second, provide an understanding of what the Japanese fashion industry can offer to Korean fashion industry and companies - that is, understand what the Japanese fashion industry's competitive edge is; and third, study the kind of global competitiveness that Korea's fashion industry must achieve. To adopt a generalized double diamond model to compare the competitiveness of the Korean and Japanese fashion industries, we selected 31 sub-variables to act as determinants of the model. That is, we extracted 31sub-variables by doing research of literature to analyze national competitiveness of the fashion industries. To measure these 31 sub-variables, secondary data was gathered. We collected data related to each sub-variable from various sources of Korea and Japan. And to calculate the competitiveness index, we took three steps with reference to previous studies. We found that status of the fashion industry of the two countries as it stands. That is, Japan is an advanced country of which fashion industry is domestic market-oriented while Korea is a small open economy that mainly focuses on the foreign market. Out of 31 proxy variables, Korea's fashion industry shows higher measurements relating to production and export than Japan, but Japan's fashion industry reports higher measurements than Korea in the fields of R&D, design and brand power, the rate of value added, the efficiency of companies and globalization. In order for Korea's fashion industry to achieve competitiveness in the global market, it should pursue the following development direction. First, it is very difficult for Korea to follow the footsteps of the U.S. and Japanese fashion industries that are able to take advantage of economies of scale, because Korea is smaller than those countries. Therefore, in the case of small economies such as Singapore, strengthening of international activities will practically improve domestic determinants that Korea should improve its domestic diamond by enhancing the current competitiveness of its international diamond. In other words, Korea needs to further endeavor to develop and expand global resources and markets as well as improve its competitiveness in terms of R&D, design and brand power, the rate of value-added, and the efficiency of companies. As the Korean fashion industry shows relatively advanced level of information technology and the fashion education system, it has considerable potential to grow. Korea is expected to have a huge growth potential since it has relatively higher level of information technology, fashion education system and activities than those of Japan in both the domestic diamond and international diamond. In particular, a better environment is laid out before Korea to gain competitiveness in the fashion industry due to the recently growing influence of the Korean Wave that Korea is expected to grow as a leader in the Asian market as well as in the global market.

• 한국의류학회지
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• 제30권9_10호
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• pp.1354-1365
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• 2006

China has a big potential as an apparel market due to its rapid economic growth. In the fashion industry, great attention has been paid to China. However, analysis of competitiveness has received relatively little attention from fashion scholarship. This study attempts to apply the double diamond model to analyze the international competitiveness of the apparel industry of China as well as of Korea. The purpose of this study is 1) to establish diamond model components in the fashion industry for Korea and China respectively, and 2) to compare the established diamond models(i.e., double diamond model, multinational diamond model) between Korea and China. Finally we suggested a marketing strategy based on the results of the double diamond model application. To build a diamond model for each country intensive literature review were conducted and additionally quantitative data were collected from 31 merchandisers and managers. We found that the domestic diamond of China was larger than Korea's, but firm strategy, structure and rivalry condition of Korea were more competitive than China's. Secondly, regarding the international diamond, China was more competitive, and especially had more the larger factor condition than Korea confirming that Korea was less competitive than China. This article provides a theoretical background and empirical findings for the competitiveness model of the fashion industry.

• 한국전기전자재료학회논문지
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• 제23권9호
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• pp.724-729
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• 2010

We have proposed a new configuration on the cathode structure to improve a neutron yield without the application of external ion sources in an inertial electrostatic confinement (IEC) device. A neutron yield in the IEC device is closely related to the potential well structure generated inside the cathode and is proportional to the ion current. Therefore, the application of a double grid cathode structure to the IEC device is expected to produce a higher ion current and neutron yield than at a single grid cathode due to a high electric field strength generated around the cathode. These possibilities were verified as compared with the ion current calculated from both shape of the single and double grid cathode. Additionally from the results of ion's lives and trajectories examined at various outer cathode voltages and grid cathode configurations by using particle simulations, the validity of the double grid cathode was confirmed.

• 한국정보통신학회논문지
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• 제17권5호
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• pp.1196-1202
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• 2013

본 연구에서는 이중게이트 MOSFET에 대한 항복전압의 변화를 채널도핑 및 소자파라미터에 따라 이차원 전위분포모델을 이용하여 분석한 것이다. 낮은 항복전압은 전력소자동작에 저해가 되고 있으며 소자의 크기가 감소하면서 발생하는 단채널 효과에 의하여 이중게이트 MOSFET의 경우도 심각하게 항복전압이 감소하고 있다. 항복전압분석을 위하여 포아송방정식의 이차원 해석학적 전위분포모델을 이용하여 채널도핑농도와 소자 파라미터인 채널길이, 채널두께, 게이트산화막 두께 등에 대하여 항복전압의 변화를 관찰하였다. 분석결과 항복전압은 채널도핑 농도의 크기뿐만이 아니라 소자크기 파라미터에 대해서 커다란 변화를 보이고 있었으며 특히 채널도핑함수인 가우시안 함수의 형태에 따라서도 큰 변화를 보이고 있다는 것을 관찰할 수 있었다.

• Geomechanics and Engineering
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• 제36권6호
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• pp.589-599
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• 2024

Dispersion occurs when clay soil disperses under specific conditions and is rapidly washed away. While there are numerous methods for rectifying it, they are neither cost nor time-effective. The current study used metakaolin and zeolite to improve heavily dispersive clay soil either separately or in combination at 0%, 2%, 4%, 6%, and 8% of the soil weight. After 7 days of curing, the samples were tested to determine the extent of change in the dispersion potential, as well as the improvement of the geotechnical properties of the soil. The results indicated that the addition of 2% zeolite with 6% to 8% metakaolin decreased the dispersion potential considerably. Double hydrometry test findings revealed that the dispersion potential decreased by almost 70% and entered the non-dispersive group; the crumb test also revealed this. Atterberg limits testing indicated a decrease in the plasticity index which reduced the flexibility of the samples. The greatest decrease in PI (67.5%) was achieved with the addition of 8% zeolite plus 8% metakaolin to the soil. The results of density tests revealed that a decrease in the optimal moisture content increased the maximum dry density of soil. This increase in density was a response to the high reactivity of metakaolin with calcium hydroxide and the formation of calcium hydroxide hydrate gel. This eventually caused an increase in the unconfined compressive strength, the greatest increase in strength of about 1.8-fold was observed with a combination of 2% zeolite and 6% metakaolin compared to the unmodified sample.

• Advances in materials Research
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• 제8권1호
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• pp.37-46
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• 2019

Electrochemical double layer capacitors (EDLCs) which are fabricated using carbon based electrodes have been emerging at an alarming rate to fulfill the energy demand in the present day world. Activated charcoal has been accepted as a very suitable candidate for electrodes but its cost is higher than natural graphite. Present study is about fabrication of EDLCs using composite electrodes with activated charcoal and Sri Lankan natural graphite as well as a gel polymer electrolyte which is identified as a suitable substitute for liquid electrolytes. Electrochemical Impedance Spectroscopy, Cyclic Voltammetry and Galvanostatic Charge Discharge test were done to evaluate the performance of the fabricated EDLCs. Amount of activated charcoal and natural graphite plays a noticeable role on the capacity. 50 graphite : 40 AC : 10 PVdF showed the optimum single electrode specific capacity value of 15 F/g. Capacity is determined by the cycling rate as well as the potential window within which cycling is being done. Continuous cycling resulted an average single electrode specific capacity variation of 48 F/g - 16 F/g. Capacity fading was higher at the beginning. Later, it dropped noticeably. Initial discharge capacity drop under Galvanostatic Charge Discharge test was slightly fast but reached near stable upon continuous charge discharge process. It can be concluded that initially some agitation is required to reach the maturity. However, the results can be considered as encouraging to initiate studies on EDLCs using Sri Lankan natural graphite.

• 대한화장품학회지
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• 제23권3호
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• pp.39-47
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• 1997

Retinol as well as RA is well known to have many beneficial effects on aged skin. But the skin irritation potential and unstable condition of the products containing them have been some problems in their cosmetic uses. So, retinol containing gel product was developed for less skin irritancy and more stability in cosmetic products. To examine the clinical effects of retinlo containing product, we used cilnicla non-invasive assessment techniques on 40 volunteers for 6 months maintaining double-blind test conditions. According to our results, the use of retinol containing product improved skin color and hydration level slightly. But there was no statistical differences. There was no erythema reaction compared to the use of RA. Especially, the skin elasticity increased above 20% and skin wrinkles of crows' feet region decreased more than 10%. Besides the instrumental analysis, a large majority of volnteers felt that their skin were improved in the case of wrunkles, elasticity, hydration and color.