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        검색결과 23

        1.
        2022.10 구독 인증기관·개인회원 무료
        Ag-containing aluminosilicate sorbents capable of capturing iodine were prepared by sol-gelation from Na, Al, and Si alkoxides using co-solvent exchange, Ag/Na ion exchange, solvent exchange, and ambient-pressure drying. The Na+AlSi-OH gel was prepared using sodium methoxide (NaOMe): aluminum tri-sec-butoxide (Al(OsBu)3): tetraethyl orthosilicate (TEOS) molar ratios of 1.05:1:1, 1.3:1.1:1, 1.5:1.3:1. The solvent effect on textural properties such as Brunauer-Emmett-Teller (BET) surface areas and pore size distributions and Ag0 particle sizes was investigated using water with high surface tension, isopropanol and n-heptane with low surface tension. The BET surface area, average pore size, and cumulative pore volume for sorbents strongly increased with decreasing surface tension of solvents and increasing Al/Si atomic ratios. In addition, Ag0 particle sizes increased with decreasing surface tension of solvents.
        3.
        2020.11 구독 인증기관 무료, 개인회원 유료
        The present study embarks from a targeted literature review to operationalize classic models of cultural communication in the territory of official Greek tourism websites. The paper explores how cultural awareness is manifested in these spaces through their structure, content and design features vis-à-vis the needs and preferences of their users. Key trends are identified and their significance is examined. Through an exploratory qualitative research, the paper identifies the factors that affect user interfaces and argues that web possibilities are not adequately exploited to promote the Greek tourism product. Websites often do not sufficiently embed emerging technologies of the digital era to address increasingly sophisticated and technology-oriented publics. With this as the backdrop, a novel conceptualization of website evaluation is offered which can be tested empirically and evolved to support functions of cultural adjustment. A concrete structure exemplifies the model and helps illustrate the cultural awareness and sensitivity parameters involved in browsing websites that support the tourism industry. The paper concludes with diagnostic findings and improvement recommendations for destination and professional web spaces to be strategically adaptive to the increasing needs of their diverse audiences.
        5,200원
        6.
        2019.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        사고저항성 핵연료의 일환으로 UO2 입자가 세라믹 셀 벽으로 둘러싸인 미세구조를 갖는 세라믹 미소셀 UO2 소결체를 개발 중이다. 이는 핵분열생성물들을 UO2 펠렛 내에 포집하여 펠렛 외부로의 방출을 저감함으로써 봉내압 상승을 완화하고 응력부식균열 발생률을 낮춘다. 생성량이나 방사능 측면에서 위험한 핵분열생성물 중 하나로 여겨지는 세슘은 세라믹 미소셀 소결체 내에서 셀 물질과 화학반응 하여 포집될 수 있다. 따라서, 세슘 포집능은 해당 화학반응의 열역학적, 속도론적 특성에 의해 결정된다. 역으로, 미소셀 소결체의 조성설계 시 해당 반응에 대한 열역학적 예측이 필수적이다. 본 연구는 세라믹 현재 개발 중인 여러 미소셀 조성(Si-Ti-O, Si-Cr-O, Si-Al-O)에 대해 세슘의 포집능을 평가하는 열역학적 계산을 다룬다. 계 산에 앞서 먼저 HSC Chemistry를 이용해 세슘과 셀 물질의 물리/화학적 상태를 정의한 후, LWR 정상운전 모사환경에서 계 산된 세슘포텐셜(ΔGCs)과 산소포텐셜(ΔG02)에 근거하여 세슘포집 반응성을 평가하였다. 계산 결과에 근거하면, 세슘 포집 반응은 상기 모든 조성에서 자발적일 것으로 예상되며 이로써 조성설계의 근거를 제시함과 동시에 세슘의 포집능을 평가하는 효과적인 방법을 제공한다.
        4,000원
        7.
        2018.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Microalgae produce not only lipids for biodiesel production but also valuable biochemicals which are often accumulated under cellular stress mediated by certain chemicals. While the microcarriers for the application of drug delivery systems for animal cells are widely studied, their applications into microalgal research or biorefinery are rarely investigated. Here we develope dual-functional magnetic microcapsules which work not only as flocculants for microalgal harvesting but also potentially as microcarriers for the controlled release of target chemicals stimulating microalgae to enhance the accumulation of valuable chemicals. Magnetic microcapsules are synthesized by layer-by-layer(LbL) coating of PSS-PDDA on Fe3O4 nanoparticle-embedded CaCO3 microparticles followed by removing CaCO3 sacrificial templates. The positively charged magnetic microcapsules flocculate microalgae by electrostatic interaction which are sequentially collected by the magnetophoretic separation. The microcapsules with a polycationic outer layer provide efficient binding sites for negatively charged microalgae and by that means are further utilized as a chemical-delivery and flocculation system for microalgal research and biorefineries.
        4,000원
        8.
        2018.07 구독 인증기관·개인회원 무료
        Despite a growing interest of value capture in the phenomenon of open innovation (OI), empirical evidence documenting the link between new product development (NPD), OI practices, and market performance is scarce. Drawing on organizational learning, NPD, and OI literature stream, this paper conceptualizes a framework in which open product innovation (OPI) practices are disentangled into two types: pre-launch OPI (which occurs before a new product is launched) and post-launch OPI (which occurs after a new product is launched). Specific types of OPI practices – technology in-licensing (i.e., pre-launch OPI) and product upgrades (i.e., post-launch OPI) – during the NPD process are expected to influence market performance of new products independently and interactively. This paper empirically analyzes the secondary data related to product innovation and market performance of 536 mobile games that were developed and launched by 265 local and global firms in South Korea. The results support hypotheses and indicate that NPD projects that engage in technology in-licensing by both local and global firms lead to better market performance than NPD projects that do not engage in. Furthermore, the more product upgrades that NPD projects employ during product life cycle, the better market performance. Finally, the involvement of active product upgrades strengthens market performance of global NPD projects that develop new products internally. The results regarding the role of pre-launch and post-launch OPI mechanisms contribute to research on OI and NPD, and also inform managers as to what product innovation practices are recommended to improve market performance of NPD projects.
        9.
        2018.07 구독 인증기관·개인회원 무료
        Hospitality and tourism industries have recognized that engaging with customers via social media is now a critical element of their marketing strategy. Given the high variability of success with which firms have been attracting customer interest online, businesses are clearly struggling to determine exactly the right methods to use the newest technologies. This study presents a predictive model of attributes for online posts that evoke a high level of customer engagement. The contribution to the literature is a unique set of features that have significant impact on customer engagement, using a big-data set to support findings. In accordance with theories originating from Social Belongingness and Brand Community Marketing, findings indicate that appeals to a sense of community belonging have a significant impact on customer engagement in social media. Specifically, communities have idiomatic vocabularies consisting of “activation words” that are especially effective for engaging customers on social media. This has both theoretical implications in that it constitutes a large-scale, real-world confirmation of belongingness hypotheses, and managerial implications in that it suggests best practices for maintaining an online presence.
        10.
        2018.07 구독 인증기관·개인회원 무료
        Due to the explosive growth of peer-to-peer transportation sharing services offered by micro-entrepreneurial travelers, investigating how their quality cues affect demand is of paramount importance. The goal of this study was to identify what types of intrinsic and extrinsic quality cues affect the demand of peer-to-peer transportation sharing services. Based on the rich data set of 414,292 transactions from a leading peer-to-peer ridesharing platform, it was identified that intrinsic quality cues – car status and driver status – and extrinsic quality cues – price and offering duration – significantly affect the peer-to-peer transportation demand independently and interactively. Although the lower price and longer offering duration of a transportation sharing service positively affect its demand, the higher price or shorter offering duration can increase its sales when combined with better intrinsic cues. Implications for vulnerable segments such as female and minority drivers are provided
        12.
        2015.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 파이로프로세싱에서 발생하는 배기체 내 요오드 포집을 위한 매질로서 고가의 은 기반 흡착제를 대체하기 위 한 상용 구리메쉬의 가능성에 대해 연구하였다. 열역학적 계산을 통해 구리 금속과 요오드 기체의 반응은 100 ~ 500℃ 온도 범위에서 자발적으로 일어나며 요오드화구리(CuI)를 형성할 것으로 예상되었다. 실험을 통해 반응 온도에 따른 요오드 포 집 효율의 영향을 분석한 결과, 1개의 구리메쉬(질량 0.26 g)를 이용하여 반응 온도를 300, 400℃로 변화하였을 때 각각 5 및 6 wt%의 요오드(초기질량 2.0 g)가 포집됨을 확인하였다. 또한, 반복 실험 결과를 토대로 구리메쉬 표면에 형성된 반응 생성 물(CuI)의 자발적인 탈리 현상으로 구리의 활용률이 증가할 수 있음을 확인하였다. 반응 생성물의 CuI 상 형성은 X-선 회절 실험을 통해 확인하였으며, 표면 분석은 주사전자현미경을 이용하여 수행하여 그 결과를 보고하였다.
        4,000원
        13.
        2015.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES: This study investigates the mechanical performance of carbon-capturing concrete that mainly contains blast furnace slag. METHODS: The mixture variables were considered; these included Portland cement content, which was varied from 10% to 40% of the blast furnace slag by weight. The specimens were exposed to different conditions such as high N2 and O2 concentrations, laboratory conditions and high CO2 conditions. Mechanical performances, including compressive and flexural strengths and carbon-capturing depth, were evaluated. RESULTS : The slump, air content and unit weight were not affected significantly by the variation in cement content. The strength development when the specimens were exposed to high purity air was slightly greater than that when exposed to high CO2. As the cement content increased the compressive and flexural strength increased but not considerably. The carbon-capturing capacity decreased as the cement content increased. The specimens exposed in the field for 70 days had flexural strength greater than 3 MPa. CONCLUSIONS : The results indicate that cement content is not an important parameter in the development of compressive and flexural strengths. However, the carbon-capturing depth was higher for less cement content. Even after field exposure for 70 days, neither any significant damage on the surface nor any decrease in strength was observed.
        4,200원
        14.
        2015.05 구독 인증기관·개인회원 무료
        Forward osmosis (FO) is an emerging technology to produce clean water with low energy consumption. The key elements in FO are a water-permeable membrane, and a draw solution inducing an osmotic pressure difference across the membrane. A desirable draw solution should result in a high osmotic pressure difference,together with an internal concentration polarization as low as possible.The draw solution should also have a very low toxicity,particularlywhen usedin drinking water purification. Furthermore, it is important to be easily recovered from a feed solution after FO operation for a certain period time. The multiple requirements make it difficult to develop an effective draw solution. In the present study, thermally and pH-sensitive oligomeric mixtures are used as potential draw solutions for FO system.
        15.
        2014.04 구독 인증기관·개인회원 무료
        Oak wilt disease caused by Raffaelea quercus-mongolicae was firstly reported at Sungnam city, Gyeonggi province, Korea, in 2004, and spread to several area of Korean peninsula. Raffaelea quercus-monglicae was transferred by ambrosia beetle, Platypus koryoensis, and caused oak wilt disease. Because oak wilt disease is mediated by ambrosia beetle, Platypus koryoensis, control of this disease concentrates on managing the ambrosia beetle population. Until now, several control methods such as felling and fumigation of dead oak trees with metham sodium, sticky-roll trap for catching emerged or attacking beetles, and oak tree logs for attraction of ambrosia beetle have been mainly used to control oak wilt disease in Korea. Although effective, current control methods have many side effects. Felling of oak tree is very difficult and dangerous to workers. To reduce the side effects of conventional control methods, new and safe types of control method for managing the ambrosia beetle populations are essential. In this study, we investigated the number of caught beetles, effect of height and direction of collection bottles by using newly developed mass capturing device for P. koryoensis to evaluate the effectiveness of this device as practical use in field.
        16.
        2013.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : In this study blast furnace slag, an industrial byproduct, was used with an activating chemicals, Ca(OH)2 and Na2SiO3 for carbon capture and sequestration as well as strength development. METHODS: This paper presents the optimized mixing design of Carbon-Capturing and Sequestering Activated Blast-Furnace Slag Mortar. Design of experiments in order to the optimized mixing design was applied and commercial program (MINITAB) was used. Statistical analysis was used to Box-Behnken (B-B) method in response surface analysis. RESULTS : The influencing factors of experimental are water ratio, Chemical admixture ratio and Curing temperature. In the results of response surface analysis, to obtain goal performance, the optimized mixing design for Carbon-Capturing and Sequestering Activated Blast- Furnace Slag Mortar were water ratio 40%, Chemical admixture ratio 58.78% and Curing temperature of 60℃. CONCLUSIONS: Compared with previous studies of this experiment is to some extent the optimal combination is expected to be reliable.
        4,000원
        17.
        2013.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : To investigate the fundamental characteristics of blast-furnace slag mortar that was hardened with activating chemicals to capture and sequester carbon dioxide. METHODS : Various mix proportions were considered to find an appropriate stregnth development in regards with various dosages of activating chemicals, calcium hydroxides and sodium silicates, and curing conditions, air-dried, wet and underwater conditions. Flow characteristics was investigated and setting time of the mortar was measured. At different ages of 3, 7 and 28days, strength development was investigated for all the mix variables. At each age, samples were analyzed with XRD. RESULTS : The measured flow values showed the mortar lost its flowability as the activating chemicals amount increased in the scale of mole concentration. The setting time of the mortar was relatively shorter than OPC mortar but the initial curing condition was important, such as temperature. The amount of activating chemicals was found not to be critical in the sense of setting time. The strength increased with the increased amount of chemicals. The XRD analysis results showed that portlandite peaks reduced and clacite increased as the age increased. This may mean the Ca(OH)2 keeps absorbing CO2 in the air during curing period. CONCLUSIONS : The carbon capturing and sequestering activated blast-furnace slag mortar showed successful strength gain to be used for road system materials and its carbon absorbing property was verified though XRD analysis.
        4,000원
        18.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        1. 세계 26개국에서 도입된 녹두 유전자원 705점에 대하여16개의 형태적 형질 특성을 이용하여 각각 두 가지의 군집방법, 핵심집단 자원수 결정방법 및 표본추출 방법을 조합하여 총8개의 핵심집단(SUNPR, SUNPPr, UNPR, UNPPr, SUNLR, SUNLPr, UNLR, UNLPr)을 작성하여 원수집단과 비교한바 8개핵심집단 모두 원수집단과는 분산과 평균치에서 차이가 없었다. 2. Nei의 다양성지수는 8개 핵심집단 모두 원수집단 보다높았고, 특히 UNLPr이 가장 높았으며, UNPR은 다른 핵심집단에 비하여 상대적으로 낮은 지수를 보였다. 3. 원수집단과 핵심집단간 자원분포의 동질성을 파악하기 위하여 카이자승 검증을 한 결과 12개 양적형질과 1개의 질적형질(종피색)은 모든 핵심집단이 동질분포를 보였으나 3개의질적 형질 (배축색, 종피광택, 생육습성)은 핵심집단에 따라서동질분포를 하는 것과 그렇지 않은 것이 있었으며, 8개 핵심집단 중 UNPPr은 동질성이 가장 높았다. 평균차율(MD%)과일치율(CR%)은 8개 핵심집단 모두 유의한 수준을 보였다. 4. 8개의 모든 핵심집단이 원수집단과 평균치에서 차이가 없고, 높은 다양성을 과 동질한 분포를 보이며, 평균차율(MD%)과 일치율(CR%)이 유의한 수준을 보여 원수집단의 다양성을잘 나타내는 것으로 해석되었다. 5. 핵심수집단 크기(10%와 15%)에 따른 다양성은 유의한차이가 없었으며, 8개의 핵심집단 중 평균치, 동질분포, 일치율 및 도복내성을 고려할 때 UNPPr이 가장 좋은 핵심집단으로 사료되었다.
        4,300원
        19.
        2020.08 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        This study investigates the short-run and long-run causal behavior of the Philippine stock market index volatility under vector error correction environment. The variables were tested first for stationarity and then long-run equilibrium relationship. Moreover, an impulse response function was estimated to examine the extent of innovations in the independent variables in explaining the Philippine stock market index volatility. The results reveal that the volatility of the Philippine stock market index exhibit long-run equilibrium relationship with Peso- Dollar exchange rate, London Interbank Offered Rate, and crude oil prices. The short-run dynamics-based VECM estimates indicate that in the short-run, increases (i.e., depreciation) in Peso-Dollar exchange rate cause PSEI volatility to increase. As for the London Interbank Offered Rate, it causes increases in PSEI volatility in the short-run. The adjustment coefficients used with the long-run dynamics validates the presence of unidirectional causal long-run relationship from Peso-Dollar exchange rate, London Interbank Offered Rate, and crude oil prices to PSEI volatility, and bidirectional causal long-run relationship between PSEI volatility and London Interbank Offered Rate. The impulse response functions developed within the VECM framework demonstrate the positive and negative reactions of PSEI volatility to unanticipated Peso-Dollar exchange rate, London Interbank Offered Rate, and crude oil price shocks.
        20.
        2020.08 KCI 등재 서비스 종료(열람 제한)
        In order to effectively control the Ricania sp., we investigated the light response to adults and developed an adult capturing device using light with superior attractiveness. The preference among six light sources such as daylight color, green, etc. for the Ricania sp. adult was favored with daylight color 97 > black 79 = red 79 = blue 79 > green 24 > yellow 13. We have developed an adult catching device using the most preferred daylight colors and behavioral habits of the Ricania sp.. The capture device consisted of two daylight compact lamps (30W, 20W), a yellow plate, and a catcher using water, and caught about 700 individuals a day. The capturing device has a large amount of capturing because adult is activity at high nighttime temperatures, but the capturing amount decreased significantly when the temperature dropped below 23℃. More than 85% of the Ricania sp. adults were trapped for 3 hours from 19:00 to 23:00. Therefore, it is considered that the adult capturing device for the control of Ricania sp. is used from mid July to late August when the night temperature is over 23℃, and lights up from 19:00 to 23:00.
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