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        검색결과 1,442

        583.
        2018.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Adsorption is one of the best methods for wastewater purification. The fact that water quality is continuously decreasing requires the development of novel, effective and cost available adsorbents. Herein, a simple procedure for the preparation of a magnetic adsorbent from agricultural waste biomass and ferrofluid has been introduced. Specifically, ferrofluid mixed with wheat straw was directly pyrolyzed either by microwave irradiation (900 W, 30 min) or by conventional heating (550°C, 90 min). Magnetic biochars were characterized by X-ray powder diffraction, Mössbauer spectroscopy, textural analysis and tested as adsorbents of As(V) oxyanion and cationic methylene blue, respectively. Results showed that microwave pyrolysis produced char with high adsorption capacity of As(V) (Qm= 25.6 mg g–1 at pH 4), whereas conventional pyrolysis was not so effective. In comparison to conventional pyrolysis, one-step microwave pyrolysis produced a material with expressive microporosity, having a nine times higher value of specific surface area as well as total pore volume. We assumed that sorption properties are also caused by several iron-bearing composites identified by Mössbauer spectroscopy ([super] paramagnetic Fe2O3, α-Fe, non-stoichiometric Fe3C, γ-Fe2O3, γ-Fe) transformed from nano-maghemite presented in the ferrofluid. Methylene blue was also more easily removed by magnetic biochar prepared by microwaves (Qm=144.9 mg g–1 at pH 10.9) compared to using conventional techniques.
        4,300원
        584.
        2018.04 구독 인증기관·개인회원 무료
        A native minute pirate bug, Orius minutus (L.), is a generalist predator of small insect pests such as thrips, mites, scale, etc. By comparing with Tetranychus urticae Koch in choice test, we evaluated the prey preference by counting number of prey killed for 4 hours on Amphitetranychus vienensis (Zacher), Frankliniella intonsa (Trybom), Stephanitis pyrioides Scott, and Eriococcus sp. nymph. Among them F. intonsa was the only one killed more than T. urticae by O. minutus. In no choice test, mean number of prey killed was highest in F. intonsa (7.2) followed by T. urticae (3.0), A. vienensis (2.4), Eriococcus sp. (2.0), and S. pyrioides (0.0) for 4 hours. This experiment shows that O. minutus could be a good predator for F. intonsa and T. urticae.
        585.
        2018.04 구독 인증기관·개인회원 무료
        Orius spp. (Heteroptera: Anthocoridae) prey on small arthropods such as aphids, thrips, whitefly, and mites both in greenhouse and field. Use of chemical attractants to natural enemies can improve the efficacy of biological control through push-pull strategy. We compared attractiveness of three synthetic herbivore-induced plant volatiles (HIPVs), i.e., nonanal, methyl anthranilate, and methyl salicylate for thrips natural enemies, O. laevigatus (Fieber) and O. minutus (L.), in Y-tube olfactometer. Mated unfed adult females of O. laevigatus showed higher choice rate to methyl anthranilate or methyl salicylate than nonanal. Orius minutus showed higher choice rate to methyl anthranilate than methyl salicylate or nonanal. These results suggest that, among the three HIPVs, methyl anthranilate can be used for the attractant of both O. laevigatus and O. minutus.
        586.
        2018.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We investigate the escape of Lyβ from emission nebulae with a significant population of excited hydrogen atoms in the level n = 2, rendering them optically thick in Hα. The transfer of Lyβ line photons in these optically thick regions is complicated by the presence of another scattering channel leading to re-emission of Hα, alternating their identities between Lyβ and Hα. In this work, we develop a Monte Carlo code to simulate the transfer of Lyβ line photons incorporating the scattering channel into Hα. Both Hα and Lyβ lines are formed through diffusion in frequency space, where a line photon enters the wing regime after a fairly large number of resonance scatterings with hydrogen atoms. Various line profiles of Hα and Lyβ emergent from our model nebulae are presented. It is argued that the electron temperature is a critical parameter which controls the flux ratio of emergent Lyβ and Hα. Specifically for T = 3 × 104 K and Hα line center optical depth α = 10, the number flux ratio of emergent Lyβ and Hα is ∼ 49 percent, which is quite significant. We propose that the leaking Lyβ can be an interesting source for the formation of Hα wings observed in many symbiotic stars and active galactic nuclei. Similar broad Hα wings are also expected in Lyα emitting halos found in the early universe, which can be potentially probed by the James Webb Telescope in the future.
        4,300원
        587.
        2018.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of this study was to evaluate the optimization extrusion variables on quality of textured vegetable protein by using response surface methodology. In this study, 50% soy protein isolate, 40% wheat gluten, and 10% corn starch were blended and 15% of the mixture was substituted with green tea. The moisture content (45, 50, and 55%), barrel temperature (130, 140, and 150oC), and screw speed (100, 150, and 200 rpm) were varied. A Box- Behnken design was used in this experiment. Second order polynomial regression equations were developed to relate the response to extrusion variables as well as to obtain a response surface plot. The independent variables had significant effects on the quality of the products and moisture content was the most significant. The lower moisture content led to the higher integrity index, lower nitrogen solubility index, lower water absorption capacity, higher texture, and higher cutting strength. The optimum conditions were identified as moisture content 47.78%, barrel temperature 150.00oC, and screw speed 196.05 rpm. Incorporation of green tea into protein materials could effectively improve the nutritional value of the product. Understanding these optimized extrusion variables on the product quality was useful for producing textured vegetable protein in the future.
        4,000원
        588.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        분리막을 이용한 분리 기술은 에너지 소요가 적다. 제올라이트를 기반으로 제작한 분리막의 경우, 결정 구조 내에 작은 분자 크기의 기공을 갖고 있어 이를 이용하여 가혹한 조건에서도 분리가 가능하기 때문에, 그 관심도가 높다. NaA (LTA 유형의 제올라이트) 제올라이트의 경우, 산업적으로 유기 용매에서 수분을 제거하는 데 많이 사용되는 데, 해당 기공 크기나 열적/수열안정성은 제올라이트 내부나 외부의 원소를 바꿔줌으로써 조절할 수 있다. 더 작은 0.28 nm 크기를 지닌 SOD 유형의 제올라이트의 경우, 수소나 물 분리에 적합하여 그 관심도가 높아지고 있으며, 이 제올라이트 유형 또한, 이온 교환과 같은 방법으로 성질을 변경할 수 있다. 제올라이트는 주변 기술 및 공정 조건에 맞게 작은 분자들을 적절하게 분리할 수 있는 분리막을 창출할 수 있다는 장점을 지닌 소재이다.
        4,000원
        589.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        방울토마토의 수경재배 중 붕소+칼슘+규소 및 칼슘+규소의 복합 엽면시비가 수확 후 품질과 MAP 저장 중 저장성에 미치는 영향을 알아보고자 본 연구를 실시하였다. 엽면시비한 방울 토마토(‘Unicorn’)는 반숙 과상태에서 수확하여 산소투과성 필름으로 포장한 5oC, 11oC, 그리고 24oC에서 25일, 15일, 10일간 저장하였다. 붕소+칼슘+규소 복합처리한 방울토마토가 3가지 저장온도 모두에서 호흡과 에틸렌 발생이 억제되어 MAP 저장중 가장 낮은 생체중 감소와 가장 높은 외관상 품질을 보였다. 수확 후 조사한 방울토마토의 경도, 산도, 비타민 C 함량은 붕소+칼슘+규소 복합처리에서 가장 높았으며, 3가지 온도 모두에서 MAP 저장 후에도 모두 높게 유지되었다. 그러나 과피색, 라이코펜 함량과 당도는 수확 후에는 엽면시비 처리로 차이가 없었으나, 3가지 온도 모두 붕소+칼슘+규소 복합처리에서 가장 낮은 수치를 보였다. 이상의 결과로 볼 때 붕소+칼슘+규소 복합처리는 방울토마토의 수확후 생리 작용을 억제하고 경도, 산도, 비타민 C 함량을 높여 저장성을 향상시키는 것으로 판단되었다
        4,000원
        590.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A diverse of recommendation has been made for the structure and management of dairy cows, despite demanding research, the relationship between lactation number and various factors is yet to be established. The present study was aimed to investigate the covariance among lactation number, growth performance, calving interval, and milk production was considered to increase an efficiency of selection schemes and to manage more efficiently Holstein dairy cows that have been raised on small-scale family farms in Republic of Korea. For that purpose, the data were observed from 850 Holstein dairy cows, which a total of 3929 milking, since April 2016 - January 2017. We measured the body weight, height, age, calving interval, and milk production of the each dairy cow. Also, information about the date of lactation, calving interval, and milk production was recorded using an automatic milking system(AMS) with identification numbers. Milk production was calculated per udder quarter in the AMS. Our study results showed the increased average body weight(p>0.05) in 1, 2, 3, and 4th lactating dairy cows and afterwards, we noticed the tendency on the average body weight(p<0.05) per lactation progressed. There was no significant difference noticed on height measurement of dairy cows. From the processing data of 850 Holstein dairy cows, the lactation number 1 and 7 had a greater calving interval with significantly lowered milk production, and the lactation number 2, 3, 4, 5, and 6 had significantly lowered the calving interval(p<0.05) with a greater milk production. From our study results, we evidenced that there is a significant relationship between the lactation number, growth performance, calving interval, and milk yield, and the maximum production of milk occurring in the 3rd and 4th lactation dairy cows. The achieved results from this study can be used by the small-scale farmers to encourage the structure and management of growth performance, calving interval, and milk yield in Holstein dairy cows in Korea.
        4,000원
        591.
        2017.12 구독 인증기관 무료, 개인회원 유료
        With the rapid development of the global economy, transport safety and security have become the key issues in maritime transportation all over the world. In practical applications, the Automatic Identification System (AIS)-based measurement of similarities between different vessel trajectories plays an important role in improving maritime transportation, e.g., maritime navigation, maritime supervision and management. However, the received AIS datasets are usually composed of a large amount of redundant information which could significantly increase the computational complexity. To deal with this problem, a Douglas-Peucker (DP)-based calculation method is introduced in this paper to accurately compress the spatio-temporal AIS trajectories while preserving the main geometrical structures. Based on the compressed trajectories, it is able to accelerate the Dynamic Time Warping (DTW) algorithm for the measurement of similarities between different vessel trajectories. In particular, the combination of DP and DTW has the capacity of significantly reducing the computational cost and guaranteeing the accuracy of similarity measures. The experimental results have demonstrated the superior performance of the proposed method in terms of computational cost and accuracy of similarity measures.
        4,000원
        592.
        2017.11 KCI 등재 구독 인증기관·개인회원 무료
        The prohibition on torture has attained status as a peremptory norm of general international law. This gives rise to the obligation erga omnes to take action against those who torture. Despite this, most world states routinely conduct torture. Is there really a worldwide prohibition of torture? Argument is framed to demonstrate that the concept of a jus cogens peremptory norm, flowing erga omnes to all nations, is in practice unattainable, preventing any absolute and universal international law prohibition against torture. States cannot declare someone an enemy of all mankind, or bind all other states to that view. Jus cogens is a text writers’ municipal communis opinio, but held administratively to be based in customary international law. Any prohibition against torture appears to remain in municipal customary law form, breaches of which are proved as arguments based on fact, eliminating operation of any absolute peremptory governing norm.
        593.
        2017.11 구독 인증기관·개인회원 무료
        The aim of this study was to determine the different soy protein concentrate (0, 15, 30, and 45%), defatted soy flour (0, 10, 20, and 30%), and wheat flour (10, 20, and 30%) contents replacing fish meal on physiochemical properties of extruded aquatic feed by using twin screw extruder. The moisture content, barrel temperature, die diameter, and screw speed were adjusted to 45%, 137°C, 4 mm, and 250 rpm, respectively. With the higher amount of soy protein concentrate replacing fish meal, the expansion ratio, swelling ratio, and water stability significantly increased while specific length and water holding capacity significantly decreased. With increasing the defatted soy flour contents, expansion ratio significantly increased, but specific length, water holding capacity and water stability significantly decreased. With increasing in the wheat flour contents, the specific length significantly decreased while the water stability significantly increased. In conclusion, high-quality aquatic feed was achieved in this study and could be used in the future.
        594.
        2017.11 구독 인증기관·개인회원 무료
        The aim of the study was to determine physiochemical properties of extruded fish feed at different barrel temperature (120, 130, and 140°C) and moisture content (35, 40, and 45%). As barrel temperature and moisture content increased, expansion ratio, water holding capacity, and water stability increased, while bulk density, hardness, and swelling ratio decreased. Soaking time had significant (P<0.05) effect on water stability. Best water stability was observed on all samples soaked for 1 h. Protein digestibility was not significantly different among the samples while protein digestibility of extruded fish feed significant higher than raw materials.
        599.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, Bi-Sb-Te thermoelectric materials are produced by mechanical alloying (MA) and spark plasma sintering (SPS). To examine the influence of the milling atmosphere on the microstructure and thermo-electric (TE) properties, a p-type Bi-Sb-Te composite powder is mechanically alloyed in the presence of argon and air atmospheres. The oxygen content increases to 55% when the powder is milled in the air atmosphere, compared with argon. All grains are similar in size and uniformly, distributed in both atmospheric sintered samples. The Seebeck coefficient is higher, while the electrical conductivity is lower in the MA (Air) sample due to a low carrier concentration compared to the MA (Ar) sintered sample. The maximum figure of merit (ZT) is 0.91 and 0.82 at 350 K for the MA (Ar) and MA (Air) sintered samples, respectively. The slight enhancement in the ZT value is due to the decrease in the oxygen content during the MA (Ar) process. Moreover, the combination of mechanical alloying and SPS process shows a higher hardness and density values for the sintered samples.
        4,000원