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        검색결과 83

        1.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this paper, the commercial anion exchange resin (IRA900) was used to investigate the adsorption properties, comparing the anion selectivity of phosphate and sulfate in water. The phosphate removal efficiency was 29.6% less than sulfate in single condition, and significantly decreased from 44.8% to 3.47 in mixed conditions while sulfate removal efficiency remained unchanged, confirming a higher selectivity for sulfate over phosphate. In the pH effect, phosphate removal efficiency increased with increase of pH due to the increased HPO4 2- species. The total removal efficiency of phosphate and sulfate was obtained approximately 62% in mixed condition, regardless of solution pH, indicating that the total anion exchange capacity was not influenced in the pH. The values of qmL and bL derived from Langmuir isotherm equation were 11.5 and 8.10 times higher for sulfate than for phosphate in mixed conditions. In single condition, sulfate and phosphate reached to equilibrium at 6 and 3 h, respectively. In mixed condition, phosphate was desorbed by the sulfate after 1h and the time to equilibrium for sulfate was retarded to 6h. Furthermore, when comparing the separation factor (αP/S), increasing the initial concentration led to higher selectivity of phosphate.
        4,000원
        2.
        2024.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aimed to investigate the catch selectivity characteristics related to the mesh arrangement of the codend in bottom trawl. Sea trials were conducted using the covered codend method from January 16 to 17, 2024, off the southern coast of Gyeongsangnam-do, focusing on the side panels of diamond and square mesh codend. A probit model was used in the selectivity analysis to estimate retention probability curves for sea pike comparing the  , , and  selectivity lengths, the selection range ( ), and the corresponding  and  values. The estimated 50% selection lengths were 23.82 cm for the diamond mesh and 25.20 cm for the square mesh whereas the corresponding selection ranges were 5.23 cm for the diamond mesh and 3.71 cm for the square mesh. The  and  values for the square mesh were lower, at 35.91 and 36.71, respectively, compared to 37.65 and 38.45 for the diamond mesh. Additionally, the retention probability at a fork length of 15 cm was lower for the square mesh than for the diamond mesh. These findings provide practical insights for gear design while contributing to the reduction of bycatch and small size fish catches in bottom trawl.
        4,000원
        3.
        2024.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study analyzed the selectivity of Octopus minor using the extended SELECT model in netpots. The data used for the analysis were collected from ten sea trials conducted between 2009 and 2010 using cylindrical octopus traps with six mesh sizes (16, 18, 20, 22, 24, and 26 mm). The selectivity analysis was performed using two models: the p-fixed split model and the p-estimated split model, depending on whether the encounter probability (split parameter) was estimated. The model fit was evaluated by comparing the model deviation and AIC values. The results showed that octopus catch decreased as mesh size increased, with a general tendency for larger individuals to be caught. The 16 mm trap, which had the smallest mesh size, accounted for 25.9% of the total octopus catch by number of individuals while the 22 mm trap, a commercial mesh size, accounted for 14.1%. The CPUE based on weight was highest for the 18 mm trap. The selectivity analysis results indicated that the p-estimated split model provided the best fit, and the 50% selection length for the 22 mm trap was 64.57 mm. In this study, reliability of various models was considered in the mesh selectivity analysis, and the findings are intended to serve as basic data for improving relevant regulations and deriving scientific research results.
        4,000원
        4.
        2024.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the refinement of Multiwalled Carbon Nanotubes (MWCNTs) derived from chemical vapor decomposition is investigated. An ultrasonic pretreatment method is employed to disentangle carbon and metal impurities intertwined with MWCNTs. The pretreated MWCNTs exhibit a marginal decrease in C–O/C = O content from 8.9 to 8.8%, accompanied by a 2.5% increase in sp3 carbon content, indicating a mildly destructive pretreatment approach. Subsequently, selective oxidation by CO2 and hydrochloric acid etching are utilized to selectively remove carbon impurities and residual metal, respectively. The resulting yield of intact MWCNTs is approximately 85.65 wt.%, signifying a 19.91% enhancement in the one-way yield of pristine MWCNTs. Notably, the residual metal content experiences a substantial reduction from 9.95 ± 2.42 wt.% to 1.34 ± 0.06 wt.%, representing a 15.68% increase in the removal rate. These compelling findings highlight the potential of employing a mild purification process for MWCNTs production, demonstrating promising application prospects.
        4,600원
        5.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        고성능 분리막 제조기술과 더불어 새로운 분리막 다단공정 설계를 통해 용매사용량 감소 및 선택도 향상이 가능 하다. 본 연구에서는 내용매성 셀룰로스 나노분리막을 제조하여 용매에 따른 용질의 선택도 차이를 비교하였다. 제막한 셀룰 로스 막을 기반으로 비극성 용매의 선택도 평가를 진행하였으며, 비극성 용매에서 용질에 대한 음배제율이 관측되었다. 특히, 분자량이 클수록 음배제율이 높아지는 역선택도의 거동을 확인하였다. 이를 기반으로 설계한 공정에서는 기존 분획 공정 대 비 3배 이상의 용매저감이 가능한 것을 확인할 수 있었다.
        4,000원
        6.
        2023.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study quantitatively evaluated size selectivity for three netting shapes (T0; regular, T45, T90) and hanging ratio (35%, 70%) of T0 netting used for trawl codend. The size selectivity experiment was performed in a tank using a cube experimental model with a length of 50 cm on one side and 389 experimental individuals, jack mackerel (Trachurus japonicus). In the selectivity analysis, a selectivity curve was created based on the selection ratio using a logistic function, and the 25%, 50%, and 70% selection length and selection range  were obtained. The T0 netting was 19.54 cm when the 50% selective length, which is a selectivity evaluation index, had a hanging ratio of 35%, a selection range of 0.51 cm, and 22.70 cm and 3.08 cm for the hanging ratio of 70%. The T45 netting was 24.34 cm and 2.13 cm, and the T90 netting was 23.51 cm and 2.84 cm. The results of the T45 netting and the T90 netting are similar, and the 50% selection length and selection range were relatively larger than the T0 netting. There was a significant difference in the correlation between the circumference of the inner circle of the mesh by the shape of the netting and the body girth of the experimental individual (Pearson test,      ). There was no significant difference in the correlation between the selection ratio by the T0 netting, T45 netting, and T90 netting with a 70% hanging ratio (one-way ANOVA,   ). The results of this study showed that selectivity such as T45 netting and T90 netting appeared when the hanging ratio, which maximizes the area of T0 netting, was maintained at 70%.
        4,000원
        7.
        2023.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, a comparative test operation was conducted through the alternate haul method to examine the selectivity of the four mesh sizes (60 mm, 90 mm, 110 mm, and 130 mm) of the trawl codend. The selectivity was analyzed using the SELECT model considering the fishing efficiency (split parameter) of each fishing gear in the comparative test fishing operation in the trawl and the maximum likelihood method for parameter estimation. A selectivity master curve was estimated for several mesh sizes using the extended-SELECT model. As a result of analyzing the selectivity for silver croaker based on the results of three times hauls for each experimental gear, it was found that the size of the fish caught increased as the size of the mesh size increased. When the selectivity for each mesh size analyzed by the SELECT model considering the split ratio was evaluated based on the size of the AIC value, the estimated split model was superior to the equal split model. Based on the master curve, the 50% selection length value was 2.893, which was estimated to be 136 mm based on the mesh size of 60 mm. In some selectivity models, there was a large deviance between observed and theoretical values due to the non-uniformity of the distribution of fished length classes. As a result, it is considered that appropriate sea trials and selectivity evaluation methods with high reliability should be applied to present trawl fishery resource management methods.
        4,200원
        10.
        2022.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the selection action on the mesh in the net pot for whelk (Buccinum opisthoplectum) is experimentally considered, and the selectivity was compared by the SELECT model and the Nashimoto’s method with the probability model according to the contact shape of the mesh and the whelk. The experiments of the mesh size selectivity was conducted for two mesh sizes: 70 mm (inner stretched size 65.4 mm) and 44 mm (inner stretched size 39.5 mm). Selectivity experiments were conducted three times in total for each mesh size used 264 whelks. In addition, Nashimoto’s method analyzed the retention probability using probability model for whether the mesh passed or not based on the carapace width of the whelk. As a result of the selectivity analysis, the 50% selection carapace width for the mesh size of 70 mm was similar to 43.62 mm in the SELECT model and 42.64 mm in the Nashimoto's method. However, the 44 mm mesh with relatively small mesh size showed differences of 40.01 mm and 26.80 mm, respectively. As for the mesh size selectivity of whelk, it was found that the smaller the mesh size, the lower the selectivity. In addition, in the selectivity study on the mesh size of whelk, an evaluation method that closely considers the contact shape between the mesh and the target species is required.
        4,000원
        13.
        2020.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The effects on the size selectivity for Muraenesox cinereus caught by coastal longline fishery were investigated in the southern coast of Korea from June 2 to 17, 2019. Four sizes of hooks (sizes 15, 17, 18 and 19) and two sizes of bait (sizes 9.9 g and 18.3 g) were tested in seven and three fishing trials, respectively. Such results revealed that smaller hook and bait size improved capture efficiency. And our results demonstrate that there was no significant size selectivity effect for hook size (ANOVA, p>0.05), but small bait improved on catching smaller fish (ANOVA, p<0.05).
        4,000원
        14.
        2020.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The mesh selectivity of a drum shaped pot for finely-striate buccinum (Buccinum striatissimum) was conducted a total of eight times with four different mesh sizes (22, 35, 50 and 60 mm) from May to September, 2019 in the eastern coastal waters of Korea. The size selectivity analysis was estimated by the SELECT method to express logistic selectivity curves. In the results, the catch of finely-striate buccinum was occupied about 90% in the total catch weight. The equation of the master curve of selectivity was estimated to s(R) = exp(-7.778R+9.983)/[1+exp(-7.778R+9.983)]. The relative shell height of 50% selection was 1.284 and the selection range (SR) was 0.282. The optimal mesh size for 50% selection on the minimum maturation size (75 mm, Shell height) was estimated more than 60 mm by the master selectivity curve.
        4,000원
        16.
        2019.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The mesh selectivity of hairtail (Trichiurus lepturus) caught by coastal drift gill net was examined in field experiments with three different mesh sizes (45, 50 and 55 mm) from October to November, 2013 in the coastal areas of south-west of Jeju province. The mesh selectivity tests were conducted with the experimental net to be set middle part of conventional driftnets. The mesh selectivity tests were carried out the total of four times. The selectivity curve was estimated by the Kitahara’s and Fujimori’s method. In the results, the catch number of hairtail was 653 (125.8 kg) and occupied 34.8% in total catches weight. The optimal mesh size for 50% selection on the minimum landing size (180 mm, AL) and the first maturity size (260 mm, AL) of hairtail were estimated as 47.2 mm and 64.5 mm by master selectivity curves, respectively.
        4,000원
        18.
        2019.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Discarding juvenile fishes under girth 16 cm nearly equal to inner perimeter of codend mesh size collected by a cover net method in bottom trawl. The body size of the main five species (mackerel, horse mackerel, sea bream, melon seed and black throat seaperch) was measured for their body length, girth, weight, height and width and analyzed size selectivity. Frequency of penetrating fish as retention in a cover net was less than 40% of total number of juvenile discarding fish. The most of body length or girth of five species were significantly different between in the codend and in the cover net. The 50% selection girth in the cover net ranged 8-11 cm were smaller than those in the codend ranged 9-13 cm by the species respectively. The 50% selection body length was significantly related with the ratio of body height (H) by body width (W) both for in the codend or in the cover net while 50% selection girth was not significantly related with H/W. Furthermore 50% selection fish size by fish species between in the codend and in the cover net was not significantly different both in body length or girth. Therefore, the girth selectivity represented possibly as one unique value regarding fish body shape was considered as more useful method for multi-species catch in trawl.
        4,000원
        20.
        2018.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        To improve the etch rate of Si3N4 thin film, H2SiF6 is added to increase etching rate by more than two times. SiO3H2 is gradually added to obtain a selectivity of 170: 1 at 600 ppm. Moreover, when SiO3H2 is added, the etching rate of the SiO2 thin film increases in proportion to the radius of the wafer. In Si3N4 thin film, there is no difference in the etching rate according to the position. However, in the SiO2 thin film, the etching rate increases in proportion to the radius. At the center of the wafer, the re-growth phenomenon is confirmed at a specific concentration or above. The difference in etch rates of SiO2 thin films and the reason for regrowth at these positions are interpreted as the result of the flow rate of the chemical solution replaced with fresh solution.
        4,000원
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