Metal halide perovskite (MHP) nanocrystals (NCs) have emerged as promising materials for various optoelectronic applications including photovoltaics, light-emitting devices, and photodetectors because of their high absorption coefficient, high diffusion length, and photoluminescence quantum yield. However, understanding the morphological evolution of the MHP NCs as well as their controlled assembly into optoelectronic devices is still challenging and will require further investigation of the colloidal chemistry. In this study, we found that the amount of n-octylamine (the capping agent) plays a crucial role in inducing further growth of the MHP NCs into one-dimensional nanowires during the aging process. In addition, we demonstrate that the dielectrophoresis process can permit self-alignment of the MHP nanowires with uniform distribution and orientation on interdigitated electrodes. A strong light-matter interaction in the MHP NWs array was observed under UV illumination, indicating the photo-induced activation of their luminescence and electrical current in the self-aligned MHP nanowire arrays.
Metal halide perovskite nanocrystals, due to their high absorption coefficient, high diffusion length, and photoluminescence quantum yield, have received significant attention in the fields of optoelectronic applications such as highly efficient photovoltaic cells and narrow-line-width light emitting diodes. Their energy band structure can be controlled via chemical exchange of the halide anion or monovalent cations in the perovskite nanocrystals. Recently, it has been demonstrated that chemical exfoliation of the halide perovskite crystal structure can be achieved by addition of organic ligands such as noctylamine during the synthetic process. In this study, we systematically investigated the quantum confinement effect of methylammonium lead bromide (CH3NH3PbBr3, MAPbBr3) nanocrystals by precise control of the crystal thickness via chemical exfoliation using n-octylammonium bromide (OABr). We found that the crystalline thickness consistently decreases with increasing amounts of OABr, which has a larger ionic radius than that of CH3NH3 + ions. In particular, a significant quantum confinement effect is observed when the amounts of OABr are higher than 60 %, which exhibited a blue-shifted PL emission (~ 100 nm) as well as an increase of energy bandgap (~ 1.53 eV).
In this study, internationally widely utilized bioeconomic models were used to make a comparison and analyze the effectiveness of red snow crab fisheries management measures. As a specific effect analysis, biological and economic effects of both total allowable catch (TAC) and effort reduction management measures were analyzed simultaneously. Model results showed that the red snow crab biomass would be decreased from 106,000 tons to 73,076 tons after ten years when the TAC is set to and maintained at the current level of 26,000 tons. The amount of biomass would be increased to 125,316 tons when the level of TAC is set to 22,000 tons. In cases of reduced fishing efforts, a 30% decrease from the current level would result in greater biomass and NPV would be also estimated at the highest level. In addition, a sensitivity analysis by market price was conducted to analyze the minimum TAC level of the red snow crab offshore pot fishery. Results showed that the minimum TAC level would be 8,210 tons when the market price increased by 30% and it would be also 15,247 tons when the market price decreased by 30%. Furthermore, results of the sensitivity analysis by fishing cost showed that the minimum TAC level was analyzed to be 13,857 tons when the fishing cost increased by 30% from the current level.
관상어는 최근 전 세계를 비롯하여 우리나라 관상어의 산업적, 사회적 가치가 재인식됨 으로써, 우리나라의 관상어 시장은 지속적으로 성장을 하고 있지만, 상품으로서는 일부 품종에만 한정되어있어 경쟁이 가능한 품종이 부족한 상태이다. 따라서 우리나라는 관상 어의 경쟁력을 확보해야 하고 뿐만 아니라 지속적인 홍보 전략 마련이 필요한 상황이다. 그리하여 본 연구는 한국 토종 담수 관상어의 대중화를 위해 일반인 10대부터 50대까지 의 다양한 연령대를 대상으로 온라인 설문조사를 실시하였다.
설문 결과, 한국 토종 담수어의 관심도는 ‘예’ 32%, ‘아니오’ 68%로 관심이 비교적 적 은 것으로 나타났다. 그리고 한국 담수 관상어의 개발현황 파악 인지도는 ‘예’ 18%, ‘아니 오’ 82%로 일반인 소비자 대부분이 개발현황 파악 인지를 하지 못 하고 있음을 알 수 있 었다. 또한, 우리나라의 소비자가 바라본 한국 담수 관상어의 개선방안은 ‘수입어종보다 아름다운 어종’ 88%, ‘홍보’ 76%, ‘사육난이도’ 43%, ‘분양비용’ 39%로 외관적인 개선과 홍보 전략이 높게 나타났다. 따라서 우리나라는 관상어의 대중화를 위해 한국 담수 관상 어의 외관적인 개선과 지속적인 홍보 전략 방안을 모색하여야 한다.
In this study, the Bayesian state-space model was used for the stock assessment of the Blackfin flounder. In addition, effective measures for the resource management were presentedwith the analysis on the effectiveness of fisheries management plans. According to the result of the analysis using the Bayesian state-space model, the main biometric value of Blackfin flounder was analyzed as 1,985 tons for maximum sustainable yield (MSY), 23,930 tons for carrying capacity (K), 0.000007765 for catchability coefficient (q) and 0.31 for intrinsic growth (r). Also the evaluation on the biological effect of TAC was done. The result showed that the Blackfin flounder biomass will be kept at 14,637 tons 20 years later given the present TAC volume of 1,761 tons. If the Blackfin flounder TAC volume is set to 1,600 tons, the amount of biomass will increase to 16,252 tons in the future. Lastly, the biological effectiveness of the policy to reduce fishing effort was assessed. The result showed that the Blackfin flounder biomass will be maintained at 13,776 tons if the current fishing efforts (currently hp) level is set and maintained. If the fishing effort is reduced by 20%, it will increase to 17,091 tons in the future. The analysis on the economic effect of TAC showed that NPV will be the lowest at 1,486,410 won in 2038, 20 years after the establishment of 2,500 tons of TAC volume. If the TAC volume is set at 2,000 tons, NPV was estimated to be the highest at 2,206,522,000 won. In addition, the analysis on the economic effect of the policy to reduce the amount of fishing effort found that NPV will be 2,235,592,000 won in 2038, 20 years after maintaining the current level of fishing effort. If the fishing effort is increased by 10%, NPV will be the highest at 2,257,575 won even thoughthe amount of biomass will be reduced.
Organic-inorganic hybrid perovskite nanocrystals have attracted a lot of attention owing to their excellent optical properties such as high absorption coefficient, high diffusion length, and photoluminescence quantum yield in optoelectronic applications. Despite the many advantages of optoelectronic materials, understanding on how these materials interact with their environments is still lacking. In this study, the fluorescence properties of methylammonium lead bromide (CH3NH3PbBr3, MAPbBr3) nanoparticles are investigated for the detection of volatile organic compounds (VOCs) and aliphatic amines (monoethylamine, diethylamine, and trimethylamine). In particular, colloidal MAPbBr3 nanoparticles demonstrate a high selectivity in response to diethylamine, in which a significant photoluminescence (PL) quenching (~ 100%) is observed at a concentration of 100 ppm. This selectivity to the aliphatic amines may originate from the relative size of the amine molecules that must be accommodated in the perovskite crystals structure with a narrow range of tolerance factor. Sensitive PL response of MAPbBr3 nanocrystals suggests a simple and effective strategy for colorimetric and fluorescence sensing of aliphatic amines in organic solution phase.
This study is aimed to compare stock assessment models depending on how the models fit to observed data. Process-error model, Observation-error model, and Bayesian state-space model for the Korean Western coast fisheries were applied for comparison. Analytical results show that there is the least error between the estimated CPUE and the observed CPUE with the Bayesian state-space model; consequently, results of the Bayesian state-space model are the most reliable. According to the Bayesian State-space model, potential yield of fishery resources in the West Sea of Korea is estimated to be 231,949 tons per year. However, the results show that the fishery resources of West Sea have been decreasing since 1967. In addition, the amounts of stock in 2013 are assessed to be only 36% of the stock biomass at MSY level. Therefore, policy efforts are needed to recover the fishery resources of West Sea of Korea.
This study is aimed to take a stock assessment of blackthroat seaperch Doederleinia seaperch regarding the fishing effort of large-powered Danish Seine Fishery and Southwest Sea Danish Seine Fishery. For the assessment, the state-space model was implemented and the standardized catch per unit effort (CPUE) of large powered Danish Seine Fishery and Southwest Sea Danish Seine Fishery which is necessary for the model was estimated with generalized linear model (GLM). The model was adequate for stock assessment because its r-square value was 0.99 and root mean square error (RMSE) value was 0.003. According to the model with 95% confidence interval, maximum sustainable yield (MSY) of Blackthroat seaperch is from 2,634 to 6,765 ton and carrying capacity (K) is between 33,180 and 62,820. Also, the catchability coefficient (q) is between 2.14E-06 and 3.95E-06 and intrinsic growth rate (r) is between 0.31 and 0.72.
In order to manage and rebuild fishery resources, the fishing effort should be controlled effectively. Especially in the setting up of the proper level of fishing efforts, economic standards as well as biological standards must be carefully considered to promote the sustainable and economically viable development of fisheries. This study is aimed to estimate optimal fishing effort of giant octopus by combo fishing which uses longline in Gangwon with statistical data. The result showed that current fishing effort is 28% higher than EMEY. Unit fishing cost for each voyage will be 27% lower and unit fishing profit will be 17% higher than the current situation when the fishing effort meets EMEY. Although current fishing effort is similar to the EMSY, current catching is 16% higher than MSY and 22% higher than MEY.
This study examines the role of visual merchandising (VMD) in creating effective interior displays for fashion “select shops”(shops that carry a wide selection of brands) amid the recent changes in consumption trends, with consumer needs becoming increasingly individualized and diversified. Fashion select shop interior displays can be categorized as self-service, showcase, counter, and environmental display spaces. Regarding the VMD elements that contribute to effective interior displays, we reached the following conclusions. First, in self-service displays, in order to heighten sales efficacy, display elements should be presented in such a way as to enable customers to select products with ease by themselves. Second, the mere presence of showcase displays was found to be insufficient; if, however, select shops use showcase displays to arrange products according to the flow of customer traffic, enabling the creation of a gentrified atmosphere for products, this may contribute to a differentiated image of brands, heightening perceived product value. Third, in counter displays, having a harmonious arrangement of display and presentation elements promotes sales by inspiring customer confidence. Fourth, regarding environmental displays, it is important for stores to have attractive interior designs and decorations in order to reproduce settings in which products are actually used, as this can inspire interest in products and promote customers’ purchasing intention.
In order to manage and rebuild fishery resources, the fishing effort should be controlled effectively. Especially in the setting up of the proper level of fishing efforts, economic standards as well as biological standards must be carefully considered to promote the sustainable and economically viable development of fisheries. This study aimed to analyze the optimal economic fishing effort (EMEY) as the most economically efficient one for the Eastern Sea Danish seine fisheries. The results showed that the optimal economic fishing effort (EMEY) of Eastern Sea Danish seine fisheries for blackfin flounder should be reduced by about 27%. That is, reducing fishing efforts up to the level of EMEY could lead to the reduction of fishing costs, thereby resulting in the increased fishing profits.
The leisure life pattern of people is changing to a familial and enthusiastic way that eventually develops the camping culture. Thus, the number of campers and the size of camping market have been dramatically increased due to significant expansion of camping people. However, many camp grounds and facilities are operating without a proper registration by government rules and regulations. In addition, many of electronic and gas equipment and tools are not used in a safe way and in a safety regulatory boundary. Therefore, campers at the camping ground is situated in a fire and safety hazard. In addition, there is limitation in rules and regulations associated with camping ground safety and fire. This study analyzed the fire and hazard guidelines and rules regulations of developed countries of campground and compared them to the current situation in South Korea. Therefore, this study is to develop a safety and fire hazard guidelines and rules and regulations related to camp ground operation, gas and electronic equipment operation and management. The study will eventually reduce the future fire and safety incidents in a campground in South Korea.
A fire sprinkler system is very important to extinguish fire in the building. The sprinkler system initiates sprinkler discharge if the detection system identifies a developing fire and opens the pre-action valve. However, pre-action fire sprinkler systems mainly installed in the underground parking lot at the apartment complex do not properly operate at fire if the connection type of fire sprinkler systems does not properly installed and operated. This study identified the relationship between fire dispersion & damage and the connection type of water supply in the sprinkler system from many fire cases at the apartment complex in South Korea. In addition, this study also identified the water supply differences and characteristics between South Korea and foreign countries. The main purpose of this study is also to improve the water connection types in the sprinkler system that can reduce the potential failures of pre-action valve operation through electrical signal system. The study also suggests the improvement plan for water connection types in pre-action fire sprinkler system that can minimize potential failure of pre-action fire sprinkler system. The suggestions for revising the fire safe standard in South Korea includes letting the water supply pipe of sprinkler system water inlet connect to the second side of pre-action valve and the water flow device that can minimize potential failure of sprinkler system.
본 연구에서는 서해안의 해양레저 대중화를 위해 누구나 세일링을 즐길 수 있고, 두 개의 킬로 선체를 지지하여 육상 및 갯벌에서도 선체가 기울지 않고 설 수 있는 트윈킬 요트를 개발하고자 한다. 기존 세일링 요트중 성능이 좋은 편인 블루워터21의 선형을 활용하고 트윈킬 요트의 경우 모노킬 요트보다는 저항성능이 불리할 것으로 예상되므로, 블루워터21의 모노킬 면적 및 무게중심 등을 고려한 트윈킬을 개발하여 모형시험을 수행하였다. 그 결과, 모노킬과 트윈킬의 저항성능에 대한 차이가 약 4 %정도로 예상보다 크지 않음을 확인하였다.
영상실감을 위한 시각과 청각의 이용은 많은 발전을 이루어 왔다. 그러나 후각을 이용한 영상의 실감증대는 기술적 한계와 기초연구의 부족으로 구현되지 못하고 있다. 특히 다양한 영상에 필요한 냄새를 각각 구현하는 것은 반드시 해결해야하는 과제이다. 한 가지 방법은 유사한 냄새들의 군집을 발견하여 각 군집의 대표냄새를 사용하는 것이다. 이를 해결하기 위한 한 가지 방법은 서로 유사한 다양한 냄새를 포괄하는 냄새군집을 발견하 여 각 군집의 대표냄새를 사용하는 것이다. 이를 위해 본 연구에서는 냄새 간 쌍유사성 평정에 근거하여 영상에 빈번하게 등장하는 냄새의 군집을 탐색하였다. 먼저 300개의 다양한 냄새를 수집하여 11개의 범주로 구분한 후 각 범주별로 빈도, 선호도, 구체성에 근거하여 152개의 냄새를 선별하였다. 참가자들은 선별된 냄새로 구성 가능 한 1,018개의 냄새쌍에 대해 유사성 평정을 실시하였고 이 결과는 다차원척도법(multi-dimensional scaling, MDS) 으로 분석하였다. 냄새들의 구체성이 낮을수록 대표냄새의 사용이 용이할 것이라는 판단 하에 MDS 결과를 냄새 구체성이 낮은 순서부터 높은 범주순서로 제시하였다. 즉 꽃, 식물, 과일, 채소범주는 냄새 구체성이 낮아 대표냄 새 사용이 용이할 것 같은 범주로 (그림 1), 화학제품, 개인생활용품, 생리적 냄새, 일상적 장소는 구체성이 높은 것과 낮은 것이 섞여 있어 대표냄새 사용에 신중해야하는 범주로 (그림 2), 식재료, 음료, 음식은 구체성이 높아 대표냄새 사용에 어려운 범주로 (그림 3) 분류하였다. 본 연구의 결과는 냄새제작 비용과 시간을 줄이고 소비자 에게 합리적인 가격의 실감서비스를 제공하는데 기여할 수 있을 것이다.
영상실감증대를 위한 시각, 청각, 촉각정보의 제시방식에 대해서는 많은 진보가 이루어 졌다. 반면 후각은 정의하기 어렵고 다루기 까다롭기 때문에 관련연구를 찾아보기 어렵다. 본 연구에서는 후각정보를 통한 영상실감증대 연구의 첫걸음으로 후각정보에 대한 사용자 수용도를 조사한 후 이에 근거하여 다양한 영상을 분류하였다. 이를 위해 먼저 영상에 냄새가 존재하는지 (냄새존재여부), 그 냄새가 실감을 증대시키는지 (실감증대효과), 영상과 함께 해당 냄새를 경험하고 싶은지 (냄새제시선호)라는 세가지 질문을 선정하였다. 각 질문들에 높은 혹은 낮은 점수를 받을 만한 다양한 장르의 영상 (51)개를 수집한 후, 참가자들에게 하나씩 영상을 시청하게 한 후 위의 세가지 질문에 대해 7점 척도로 평정하게 하였다. 영상분류를 위해 두 질문씩 쌍으로 묶어 각 질문의 척도를 2차원 평면의 X, Y축으로 설정한 후 평정값을 이용하여 영상분류를 위한 산포도를 구성하였다. 2차원 평면의 서로 다른 사분면에 위치한 영상군집들은 영상실감증대를 위한 후각정보 제시에 중요한 시사점을 줄 것으로 기대한다.
In this study, we evaluated the composition of smoke released from fish frying processes. We selected 4 fish types (mackerel (M), hairtail (H), croaker (C), and japanese mackerel (J)) which are commonly served in our daily diet and collected their smoke samples. The analysis was made to cover both toxic and hazardous volatile organic compounds (VOCs) that include benzene, toluene, p-xylene, methyl ethyl ketone, methyl isobutyl ketone, butyl acetate, and isobutyl alcohol. According to our analysis, the mean concentrations (ppb) of VOCs derived from all 4 fish types were 254.5 (benzene), 34.5 (toluene), 833.0 (MEK), 29.4 (MIBK). Benzene as the class one carcinogen was detected at fairly high levels from these fish smoke samples so as to exceed indoor emission standard. Considering that roasted fish is often included as one of the common diet items, we can confirm that the smoke released from cooking should be controlled to reduce the possibility of their exposure to human.