• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.170-173
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• 2001

Thin films of phase-pure perovskite (P $b_{0.72}$L $a_{0.28}$) $Ti_{0.93}$ $O_3$(PLT) were deposited in-situ onto Pt/Ti/ $SiO_2$/Si substrates by pulsed laser deposition. We have systematically investigated the variation of grain sizes depending on the process condition. Both in-situ annealing and ex-situ annealing treatments have been compared depending on the annealing time. Two-step process to grow (P $b_{0.72}$L $a_{0.28}$) $Ti_{0.93}$ $O_3$(PLT) films was adopted and verified to be useful to enlarge the grain size of the film and to enhance the leakage current characteristics. The grain sizes of PLT thin films were successfully controlled 260 to 350 nm by changing process parameters. Electrical properties including dielectric constant, ferroelectric characteristics, crystallization and leakage current of PLT thin films were shown to be strongly inf1uenced by grain size. Also PLT thin films on p-type(100) Si substrate will be fabricated by pulsed laser deposition technique using a Nd:YAG laser with different wavelengths of 355, 532 and 1064 nm. Effect of the variation of laser wavelength on dielectric properties will be discussed. Microstructural and electrical properties of the film were investigated by C-V measurement leakage current measurement and SEM.ent and SEM.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.281-281
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• 2010

Very low refractive index (<1.4) materials have been proved to be the key factor improving the performance of various optical components, such as reflectors, filters, photonic crystals, LEDs, and solar cell. Highly porous SiO2 are logically designed for ultralow refractive index materials because of the direct relation between porosity and index of refraction. Among them, ordered macroporous SiO2 is of potential material since their theoretically low refractive index ~1.10. However, in the conventional synthesis of ordered macroporous SiO2, the time required for the crystallization of organic nanoparticles, such as polystyrene (PS), from colloidal solution into well ordered template is typical long (several days for 1 cm substrate) due to the low interaction between particles and particle - substrate. In this study, polystyrene - polyacrylic acid (PS-AA) nanoparticles synthesized by miniemulsion polymerization method have hydrophilic polyacrylic acid tails on the surface of particles which increase the interaction between particle and with substrate giving rise to the formation of PS-AA film by simply spin - coating method. Less ordered with controlled thickness films of PS-AA on silicon wafer were successfully fabricated by changing the spinning speed or concentration of colloidal solution, as confirmed by FE-SEM. Based on these template films, a series of macroporous SiO2 films whose thicknesses varied from 300nm to ~1000nm were fabricated either by conventional sol - gel infiltration or gas phase deposition followed by thermal removal of organic template. Formations of SiO2 films consist of interconnected air balls with size ~100 nm were confirmed by FE-SEM and TEM. These highly porous SiO2 show very low refractive indices (<1.18) over a wide range of wavelength (from 200 to 1000nm) as shown by SE measurement. Refraction indices of SiO2 films at 633nm reported here are of ~1.10 which, to our best knowledge, are among the lowest values having been announced.

• 한국전기전자재료학회논문지
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• 제37권4호
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• pp.445-450
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• 2024

The expansion of lithium-ion battery usage beyond portable electronic devices to electric vehicles and energy storage systems is driven by their high energy density and favorable cycle characteristics. Enhancing the stability and performance of these batteries involves exploring solid electrolytes as alternatives to liquid ones. While sulfide-based solid electrolytes have received significant attention for commercialization, research on amorphous-phase glass solid electrolytes in oxide-based systems remains limited. Here, we investigate the glass transition temperatures and sintering behaviors by changing the molecular ratio of Li₂O/B₂O₃ in borate glass comprising Li₂O-B₂O₃-Al₂O₃ system. The glass transition temperature is decreasing as increasing the amount of Li₂O. When we sintered at 450℃, just above the glass transition temperature, the samples did not consolidate well, while the proper sintered samples could be obtained under the higher temperature. We successfully obtained the borate glass ceramics phases by melt-quenching method, and the sintering characteristics are investigated. Future studies could explore optimizing ion conductivity through refining processing conditions, adjusting the glass former-to-modifier ratio, and incorporating additional Li salt to enhance the ionic conductivity.

• 대한간호학회지
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• 제30권1호
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• pp.122-136
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• 2000

Chronic illness requiring attention and management during a long period of time puts great burden onto patients, their family and society. For patients with chronic illnesses, providing social support is the most important, and the fundamental support comes from their spouses. Amount and quality of support from spouses seems to differentiated according to the sex of patients. Female patients tend to believe that their spouses are not very supportive. Therefore, the researchers assessed the burden of husbands of female arthritis patients to discover the factors that result in greater burden. Also, they developed a theoretical model of husbands′ care for their wives through a qualitative research into husbands′ experience. Method 1: The study material was 650 female arthritis patients registered in an arthritis clinic. The questionnaire about the disease experience of female arthritis patients and the burden of husbands were sent. Returned questionnaires numbered 210(32.3%) and 27 were excluded because of inadequate answers. The remaining 183 questionnaires were analyzed. The mean age of the patients was 51 years and the mean age of spouses was 55 years. The mean marital period was 28 years. The average duration since diagnosis was 9.1 years. Education level was varied from primary school to graduate school, and average income/month was 1,517,300 won. Method 2: Initial questionnaire studies on the burden of husbands were performed. Among 183 responding husbands, 23 consented to participate for a qualitative research. Data was obtained by direct and telephone interviews. The mean age of participants was 58 years, and the educational level and socioeconomic status also varied. Result: 1. Husbands′ burden: The average burden was 57.68 with a range of 6-96. 2. Burden and general characteristics: The husband′s burden correlated with the age of the patients, numbers in the family, therapy methods, patient′s level of discomfort, patient′s disease severity, patient′s level of dependence and the husband′s understanding of the level of severity. 3. Linear correlation analysis on burden: The husbands′ burden is explained in 22.5% by husband′s recognition of level of severity and husbands′ age. 4. There were four patterns of the burden on husbands: both objectve burden and subjective burden were high(pattern I), both of objectve burden and subjective burden were low(pattern II), objective burden was high but subjective burden was low(pattern III), objective burden was low but subjective burden was high(pattern IV). The pattern was correlated with the family income, educational level of the patients and their husbands, therapy methods, patient′s level of discomfort, patient′s disease severity, patient′s level of dependence and husband′s understanding of level of severity. 5. The core category of the caring experience of the husbands with arthritis patients was "companionship". The causal factor was the patients′ experience due to symptoms : physical disfigurement, pain, immobility, limitation of house chores, and limitation of social activities. Contextural factors are husbands′ identification of housework and husbands′ concern about the disease. The mediating factors are economic problems, fear of aging, feeling of limitation and family support. The strategy for interaction is mind control and how to solve emotional stress. The "companionship" resulted from caring activities, participation of household activities, helping patients′ to coping with emotional experience. 6. Companionship is established through the process of entering intervention, and caring state of mind. Entering intervention is the phase of participation of therapy and involvement of houseworks. The caring phase consists of decision on therapy, providing therapy, providing direct care, and taking over the household role of wife. Through caring phase, the changing phase set a stage in which husbands consolidate the relationship with their wives, and are reminded of the meaning of marriage. As a result, in changing phase, husbands′ companionship is enhanced. In conclusion, nursing care of chronic illnesses should include a family member especially the spouse. All information on disease shoud be provided to patients and whole family member. Strong support should also be provided to overcome difficulties in taking over role of other sex. Then the quality of life of patients and families will be much improved.

• 자원리싸이클링
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• 제29권5호
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• pp.55-63
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• 2020

묽은 염산용액에서 이온성액체에 의한 코발트(II)와 니켈(II)의 분리를 조사하기 위해 이온성액체의 종류와 농도 및 수상의 초기 pH를 변화시켜 추출실험을 수행했다. 본 논문에서는 유기인산(D2EHPA, PC88A, Cyanex 272, Cyanex 301)을 Aliquat 336과 반응시켜 제조한 이온성액체와 Aliquat 336의 염소이온을 SCN과 치환한 이온성액체를 사용했다. 세 종류의 이온성액체(ALi-D2, ALi-PC, ALi-CY272)에 코발트(II)가 니켈(II)보다 추출이 잘 되었으며 평형 pH가 초기 pH보다 높았다. ALi-CY301의 경우 코발트(II)와 니켈(II)의 선택도는 추출조건에 의존했다. 또한 상기 이온성액체에 TBP의 첨가가 두 금속의 추출에 미치는 영향도 조사했다. 추출제로 ALi-SCN를 사용하는 조건에서 코발트(II)가 선택적으로 추출되어 두 금속을 완전히 분리하는 것이 가능했다.

• 한국전자파학회논문지
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• 제17권9호
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• pp.900-912
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• 2006

본 논문에서는 1.575 GHz에서 운용되는 미사일 탄두 탑재형 GPS 수신 안테나를 원형 패치 안테나 구조로 미사일 탄두부의 중간에 장착하였으며, 원형 링 구조의 단락 핀을 이용하여 패치면과 접지면을 연결하였다. 제안된 안테나는 이중 급전과 이중 급전점의 위상 차이를 이용하여 미사일 비행 축과 수직한 방향(H-면)에서 무지향성의 방사 특성을 갖도록 설계되었다. 유전체로 1.6 mm 높이의 $FR4(\varepsilon_r=4.6)$를 사용하였으며 무지향성 방사패턴은 원형 패치 직경 59.5 mm, 단락 핀 직경 14 mm일 때 최적화되었다. 또한 실제 미사일 형태를 갖도록 직경 100 mm, 길이 500 mm의 원통형 몸체를 탄두 하단부에 장착하였다. 이때 이중 급전점의 사이각과 이중 급전점의 위상을 변화시키면서 H-면에서의 방사 패턴의 변화를 측정하였으며 그 결과, 이중 급전점의 사이각과 이중 급전점의 위상 차이가 각각 $100^{\circ}$일 때 이득 -5.55 dBd, 최대/최소 방사 전력 레벨 차 3.98 dB를 갖는 무지향성에 가까운 방사 패턴 특성을 얻을 수 있었다.

• World Technopolis Review
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• 제4권1호
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• pp.11-22
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• 2015

Globalization, increasing technological advancements and dynamic knowledge diffusion are moving our world closer together at a unique scale and pace. At the same time, our rapidly changing society is confronted with major challenges ranging from demographic to economic ones; challenges that necessitate highly innovative solutions, forcing us to reconsider the way that we actually innovate and create shared value. As such the linear, centralized innovation models of the past need to be replaced with new approaches; approaches that are based upon an open and collaborative, global network perspective where all innovation actors strategically network and collaborate, openly distribute their ideas and co-innovate/co-create in a global context utilizing our society's full innovation potential (Innovation 4.0 - Open Innovation 2.0). These emerging innovation paradigms create "an opportunity for a new entrepreneurial renaissance which can drive a Cambrian like explosion of sustainable wealth creation" (Curley 2013). Thus, in order to materialize this entrepreneurial renaissance, it is critical not only to value but also to actively employ this new innovation paradigms so as to derive community-driven shared value that stems from global innovation networks. This paper argues that there is a gap in existing business incubation model that needs to be filled, in that the innovation and entrepreneurship community cannot afford to ignore the emerging innovation paradigms and rely upon closed incubation models but has to adopt an "open incubation" (Ziouvelou 2013). The open incubation model is based on the principles of open innovation, crowdsourcing and co-creation of shared value and enables individual users and innovation stakeholders to strategically network, find collaborators and partners, co-create ideas and prototypes, share their ideas/prototypes and utilize the wisdom of the crowd to assess the value of these project ideas/prototypes, while at the same time find connections/partners, business and technical information, knowledge on start-up related topics, online tools, online content, open data and open educational material and most importantly access to capital and crowd-funding. By introducing a new incubation phase, namely the "interest phase", open incubation bridges the gap between entrepreneurial need and action and addresses the wantpreneurial needs during the innovation conception phase. In this context one such ecosystem that aligns fully with the open incubation model and theoretical approach, is the VOICE ecosystem. VOICE is an international, community-driven innovation and entrepreneurship ecosystem based on open innovation, crowdsourcing and co-creation principles that has no physical location as opposed to traditional business incubators. VOICE aims to tap into the collective intelligence of the crowd and turn their entrepreneurial interest or need into a collaborative project that will result into a prototype and to a successful "crowd-venture".

• 자원리싸이클링
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• 제29권1호
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• pp.17-24
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• 2020

침철석을 주요 맥석광물로 하는 난용성 자원으로부터 희토류를 회수하기 위해 화학적 분해-산 침출의 2단계 방법을 이용한 맥석광물 분해 및 희토류 침출율 향상 연구를 수행하였다. 화학적 분해에는 알칼리인 NaOH를 사용하였으며 NaOH 용액 농도 20-50 wt%, 광액 농도 10% (w/w), 온도는 각 농도에서 NaOH 용액이 끓지 않는 최대 온도로 하여 분해 반응을 진행하였다. NaOH 농도가 높아질수록 경희토류 (Ce, La, Nd) 와 철은 고체상의 분해 산물 내에 농축되는 경향을 나타냈으며, 알루미늄과 인은 용액상으로 제거되어 50 wt% NaOH로 분해 시 고체상에 각각 0.96%, 0.17% 만이 잔류하는 것으로 나타났다. 또한, 주요 맥석광물인 침철석의 결정성이 분해 과정 후 감소하는 것으로 분석되었다. 50 wt% NaOH 분해 산물을 3.0 M 염산, 80 ℃ 조건에서 3시간 동안 침출했을 때, 94% 이상의 희토류 침출율을 달성하였으며 (Ce 80%), 불순물 중 알루미늄 침출율이 12%, 인 침출율이 0%로 감소하여 본 광석에 대한 최적 분해 및 침출 조건으로 선정하였다. 본 실험 결과로부터 희토류와 철의 침출율 간에 양의 상관관계가 있는 것으로 분석되었으며, 따라서 침철석의 결정성 감소가 희토류 침출율 향상에 기여한다고 할 수 있다.

• 한국건설순환자원학회논문집
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• 제7권1호
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• pp.60-68
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• 2012

이 연구에서는 건물의 사용에 있어서 잠열의 축열 성능을 이용하여 에너지를 절감할 수 있는 축열 건자재로서 멜라민 수지를 콘크리트 벽체 물질로 하는 파라핀 왁스의 마이크로 캡슐화를 통한 축열미립자의 제조에 관하여 연구하였다. 마이크로 캡슐화 공정에 있어서 계면활성제로서 SDS의 첨가량이 미치는 영향을 검토하였으며 제조된 축열미립자의 축열 성질을 비교하였다. SDS가 첨가됨에 따라서 마이크로캡슐화가 가능하였으며 첨가량이 증가함에 따라서 보다 단단한 캡슐이 형성되었다. 또한 적정 첨가량에서는 매우 균일한 재료가 형성되었다. 또한 SDS 첨가량은 제조된 축열 미립자의 축열 성질에도 영향을 크게 미쳤으며 첨가량이 증가할수록 왁스의 융점 온도에서 열 저장 및 방출 현상이 뚜렷히 관찰되었다. 이 연구는 건물의 사용 에너지 절감을 위해 마이크로 캡슐화된 PCM을 콘크리트 벽체에 적용하는 연구 시리즈의 일부이다.

• 한국재료학회지
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• 제26권4호
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• pp.173-181
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• 2016

In order to use coal tar pitch (CTP) as a raw material for carbon fibers, it should have suitable properties such as a narrow range of softening point, suitable viscosity and uniform optical properties. In this study, raw CTP was modified by heat treatment with three types of polymer additives (PS, PET, and PVC) to make a spinnable pitch for carbon fibers. The yield, softening point, C/H ratio, insoluble yield, and meso-phase content of various modified CTPs with polymer additives were analyzed by changing the type of polymer additive and the heat treatment temperature. The purpose of this study was to compare the properties of CTPs modified by polymer addition with those of a commercial CTP. After the pitch spinning, the obtained green fibers were stabilized and carbonized. The properties of the respective fibers were analyzed to compare their uniformity, diameter change, and mechanical properties. Among three polymer additives, PS220 and PET261 pitches were found to be spinnable, but the carbon fibers from PET261 showed mechanical properties comparable with those of a commercial CTP produced by an air-blowing method (OCI284). The CTPs modified with polymer additive had higher ${\beta}$-resin fractions than the CTP with only thermal treatment indicating a beneficial effect of carbon fiber application.