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        검색결과 9,921

        2281.
        2020.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The goal of this study was to evaluate effects of various microbial and organic additives on chemical compositions, fermentation indices, and aerobic stability of barley silage. Youngyang barley harvested at 31.5% dry matter (DM), and ensiled into 20 L bucket silo for 0, 1, 3, 7, 48, and 100 d in quadruplicates with four additives following: sterile destilled water at 1% of fresh forage (CON); Lactobacillus plantarum at 1.2 x 105 cfu/g of fresh forage (CL); Lactobacillus buchneri at rate of 1.2 x 105 cfu/g fresh forage (LB); Fermented Persimmon Extract at 1% of fresh forage (FPE); and Essential Oil at 1% of fresh forage (EO). On 100 d of ensiling, CL and FPE silages had lower (p<0.05) DM than CON silage. Additionally, FPE silage had higher (p<0.05) crude protein than CON silage. All silages with additives, except EO, had higher (p<0.05) neutral detergent fiber (NDF) than CON silage. Silage treated with CL, LB, and FPE had lower in vitro DM digestibility than CON silage, and silages treated with LB and FPE had higher in vitro NDF digestibility (IVNDFD) on 100 d of ensiling. The PFE silage produced the highest (p<0.05) lactate during ensiling period, while LB silage produced the highest (p<0.05) acetate. All inoculated silages had higher (p<0.05) LAB count than control silage. Only CL silage had higher (p<0.05) yeast count than control silage, while the other silages were not differ compared to CON silage. The aerobic stability was higher (p<0.05) in LB and FPE silages than in CON silage. In conclusion, FPE could be an alternative additive to increase IVNDFD, fermentation indices, and aerobic stability of barley silage.
        4,000원
        2282.
        2020.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this work, the electrical explosion of wire in liquid and subsequent spark plasma sintering (SPS) was introduced for the fabrication of Ni-graphite nanocomposites. The fabricated composite exhibited good enhancements in mechanical properties, such as yield strength and hardness, but reduced the ductility in comparison with that of nickel. The as-synthesized Ni-graphite (5 vol.% graphite) nanocomposite exhibited a compressive yield strength of 275 MPa (about 1.6 times of SPS-processed monolithic nickel ~170 MPa) and elongation to failure ~22%. The hardness of Nigraphite composite had a value of 135.46 HV, which is about 1.3 times higher than that of pure SPS-processed Ni (105.675 HV). In terms of processing, this work demonstrated that this processing route is a novel, simple, and low-cost method for the synthesis of nickel-graphite composites.
        4,200원
        2283.
        2020.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we investigated the effects of precipitates and oxide dispersoids on the high-temperature mechanical properties of oxide dispersion-strengthened (ODS) Ni-based super alloys. Two ODS Ni-based super alloy rods with different chemical compositions were fabricated by high-energy milling and hot extrusion process at 1150℃ to investigate the effects of precipitates on high-temperature mechanical properties. Further, the MA6000N alloy is an improvement over the commercial MA6000 alloy, and the KS6000 alloy has the same chemical composition as the MA6000 alloy. The phase and microstructure of Ni-based super alloys were investigated by X-ray diffraction and scanning electron microscopy. It was found that MC carbide precipitates and oxide dispersoids in the ODS Ni-based super alloys developed in this study may effectively improve high-temperature hardness and creep resistance.
        4,000원
        2284.
        2020.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this research, a new medium-entropy alloy with an equiatomic composition of FeCuNi was designed using a phase diagram (CALPHAD) technique. The FeCuNi MEA was produced from pure iron, copper, and nickel powders through mechanical alloying. The alloy powders were consolidated via a high-pressure torsion process to obtain a rigid bulk specimen. Subsequently, annealing treatment at different conditions was conducted on the four turn HPT-processed specimen. The microstructural analysis indicates that an ultrafine-grained microstructure is achieved after post-HPT annealing, and microstructural evolutions at various stages of processing were consistent with the thermodynamic calculations. The results indicate that the post-HPT-annealed microstructure consists of a dual-phase structure with two FCC phases: one rich in Cu and the other rich in Fe and Ni. The kernel average misorientation value decreases with the increase in the annealing time and temperature, indicating the recovery of HPT-induced dislocations.
        4,000원
        2289.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The root of Paeonia lactiflora has been used in Chinese medicine. We conducted to check the comparative qualities of ethanol solvent extraction (PLE) and supercritical carbon dioxide extraction (PLS) of P. lactiflora root. PLE had higher antioxidant and polyphenol contents than PLS. But, PLS were significantly increased peroxisome proliferator-activated receptor (PPAR)-α. In addition, PLS inhibited the adipocyte differentiation of 3T3-L1 cells. When treated with the extract at a concentration of 100 μg/mL, the Wnt/β-catenin pathway reporter luciferase activity of HEK 293-TOP cells increased approximately by 3-folds compared to that of the untreated control group. These results indicate that P. lactiflora supercritical carbon dioxide extract may serve as a cosmeceutical for improving skin barrier function and the treatment of obesity.
        4,000원
        2290.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we prepared ACFs with a high specific surface area from various precursors (rayon, pitch, and oxidized polyacrylonitrile-based fibers) by a steam-activation technique and investigated the effects of the micropore and mesopore fraction on 2-CEES adsorption behaviors. The activation time was precisely controlled so that the activation yield was in the range of 35–40% to ensure the mechanical properties of the ACFs. The N2 adsorption isotherm characteristics at 77K were confirmed by Brunauer–Emmett–Teller, Barrett–Joyner–Halenda and non-local density functional theory equations. The adsorption capacities of the ACF were measured by breakthrough experiments in the gas phase (750 μg/mL of 2-CEES in N2 flow). The removal efficiency of the ACFs was evaluated and compared with that of AC. From the results, specific surface areas and total pore volume of the ACF were determined to be 1380–1670 m2/g and 0.61–0.82 cm3/g, respectively. It was also observed that various pore characteristics of ACF were found to be dependent on crystallite structure of each precursor. The break through time (C/C0 = 0.10) was in the order of Oxi-Pan-H-9-2 < Saratoga AC < Rayon-H-9-3 < Pitch-H-9-4. This indicates that 2-CEES adsorption capacity could be a function not only of specific surface area or total pore volume, but also of sub-mesopore volume fraction in the range of 1.5–2.5 nm of adsorbents.
        4,000원
        2291.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study presents an efficient clothes-sizing system for those experiencing obesity in old age with the aim of revitalizing the clothing industry for older obese people. The study targets 249 obese men aged 60 to 85 who satisfy a Rohrer index score of 1.6 or higher and a BMI (body mass index) of 25 or higher. Elderly obese males showed more obesity in the body based on the waist. In particular, those in their 60s were the most obese, and after reaching their 70s, characteristics of old age in which the stature was reduced and the limbs were tapered were shown. The clothes-sizing system was set to 5cm in stature, 5cm and 3cm in chest girth, 2cm in waist girth (omphalion), and 2cm in hip girth according to the KS standards. Through the two-way distribution of each section, the name of the section with a high distribution was given. Casual tops were selected from eight sizes, ranging from 155 to 170cm in stature and 95 to 105cm in chest girth. Suit top sizes were selected from eight sizes, ranging from 160 to 170cm in stature and 94 to 103cm in chest girth. Bottoms suggested 10 sizes distributed between 90 and 100cm in waist girth (omphalion) and 92 and 98cm in hip girth. According to the KS standards, the detailed size was divided into the basic part and the reference part.
        4,500원
        2292.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A new discrete bis-dithiolene complex, [ PPh4]2[Zn(DMED)2] (1; DMED = 1,2-dicarbomethoxy-1,2-dithiolate) with sulfurbased radical character was synthesized and structurally characterized. Complex 1 is stable and exhibits a square planar geometry around the zinc metal. 1 forms nanospheres through a one-pot water-induced self-assembly in a mixture of solvents (acetonitrile–water). These nanospheres were further decorated with water-soluble carbon nanotubes (wsCNTs) through hydrogen bonding between the peripheral –COOCH3 groups of 1 and surfacial carboxyl groups of wsCNTs to assemble into a spherical nanocomposite. The as-prepared nanocomposite showed fluorescence emissions in visible region due to the separation of energy states of the nanospheres assisted by wsCNTs, suggesting the future possibilities of these new materials for use in biomedical application.
        4,000원
        2293.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적 : 각막굴절교정수술 후 저평가되는 안압을 다양한 각막 절삭량에 따라 경도, 중등도, 고도 근시 군을 나누어 조사하고, 각 군별로 가장 적합한 수술 후의 안압 보정방법을 제시하고자 하였다. 방법 : 각막굴절교정수술을 받은 평균 연령 26.89±5.18세의 남녀 501명 1,002안(남자 237명, 여자 264명)을 대상으로 하였다. 안압은 비접촉식 안압계를 이용하여 측정하였고, 수술 후 저평가된 안압을 보정하기 위해 Ehlers, Shah, Dresden, Orssengo/Pye의 보정방법을 이용하였다. 다양한 각막 절삭량에서의 안압 차이를 비교하기 위해 세 그룹으로 나누어 분석하였다. 결과 : 비접촉식 안압계로 측정한 수술 전 안압은 15.67±2.39 mmHg이었고, 수술 후 안압은 10.12±2.11 mmHg로 평균 5.55±2.09 mmHg 만큼 유의하게 낮게 측정되었다. Ehlers의 보정방법으로 산출된 수술 후의 안압은 14.53±2.47 mmHg로 수술 전 안압과 평균 1.14±2.83 mmHg 차이를 보여 네 가지 보정방법 중에서 수술 전 안압 측정치와 가장 비슷한 수치를 보였다. 또한 각막 절삭량에 따라 나눈 경도, 중등도, 고도근시 각 군 모두에서 Ehlers 식으로 보정된 안압이 수술 전 안압과 차이가 가장 적게 나타났다. 결론 : 굴절교정수술 후 고도근시를 포함한 다양한 근시군 모두에서 4가지 보정방법 중 Ehlers 보정법이 가장 유용한 것으로 판단된다. 이 결과는 각막굴절교정수술 후 저평가되는 안압의 실제 값을 산출하여 녹내장에 대한 조기진단 및 치료시기가 늦어지는 것을 막는 데에 활용할 수 있을 것이라 생각된다.
        4,200원
        2294.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적 : 청광 차단렌즈의 효과를 정량적으로 분석하는 방법을 새롭게 제시하고, 이를 시판하고 있는 기능성 렌즈에 적용하여 비교 분석함으로써 그 활용 가능성을 확인하고자 하였다. 방법 : 렌즈의 광투과율을 측정하고, 청광 차단 효율 함수를 적용하여 효율에 대한 정성적인 분석을 하였다. 또한 청광 차단 효율 결과를 적분하여 수치화하는 정량적인 분석 방법을 새롭게 도입하여, 시판중인 청색광차단 기능성 렌즈에 적용하여 비교분석하였다. 결과 : 정성적인 분석 방법을 일반렌즈, 코팅방법으로 제작된 2종의 렌즈와 착색방법으로 제작된 1종의 렌즈에 적용한 결과, 모든 렌즈는 단파장 영역의 빛을 차단하는 효과가 우수한 것으로 분석되었다. 하지만 정량적인 분석 방법에 의한 결과에서는 각 렌즈별 다소 차이가 있음을 확인하였다. 결론 : 다양해지는 디스플레이 장치 및 스마트폰의 광 특성이 날로 진화되고 변화되고 있으므로, 다양한 방법으로 광원과 광학제품에 대한 광특성 분석이 요구된다. 이에 따라, 본 연구에서 새롭게 도입한 정량적인 분석 방법이 효과적인 수단일 될 수 있는 가능성을 확인 하였다.
        4,000원
        2295.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Agrobacterium tumefaciens mediated gene transfer is widely used to generate genetic transformation of plants and transient assay of temporal exogenous gene expression. Syringe infiltration system into tobacco (Nicotiana benthamiana) leaves is a powerful tool for transient expression of target protein to study protein localization, protein-protein binding and protein production. However, the protocol and technical information of transient gene expression, especially double strand RNA (dsRNA), in tobacco using Agrobacterium is not well known. Recently, dsRNA is crucial for insecticidal effect on destructive agronomic pest such as Corn rootworm. In this study, we investigated the factor influencing the dsRNA expression efficiency of syringe agro-infiltration in tobacco. To search the best combination for dsRNA transient expression in tobacco, applied two Agrobacterium cell lines and three plant vector systems. The efficiency of dsRNA expression has estimated by real-time PCR and digital PCR. As a result, pHellsgate12 vector constructs showed the most effective accumulation of dsRNA in the cell. These results indicated that the efficiency of dsRNA expression was depending on the kind of vector rather than Agrobacterium cells. In summary, the optimized combination of transient dsRNA expression system in tobacco might be useful to in vivo dsRNA expression for functional study and risk assessment of dsRNA.
        4,000원
        2296.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 SNS(social network service)를 통한 화훼상품 구매인식과 화훼상품 이미지 선호도를 알아보고자 국내 성인남녀 311명을 대상으로 설문을 진행하였다. 소비자들이 SNS를 통해 화훼상품을 구매하는 가장 큰 이유로는 트렌드에 맞는 디자인을 판매하기 때문이며, 해당 항목에 대하여 20대가 가장 높은 평균으로 나타났다. 연령에 따라 20대와 30대의 응답자는 40대에 비해 SNS를 통해 판매하는 화훼상품의 가격이 덜 합리적이라고 생각하였으며, 50대 이상의 연령에서는 SNS를 통해 판매하는 화훼상품의 품질과 꽃의 신선도에 대해 낮게 신뢰하는 것으로 나타났다. 응답자들은 SNS에 게시된 화훼 상품의 이미지가 구매할 상품 선택에 많은 도움을 준다고 인식하였으며, SNS상의 화훼상품 이미지에 대해 긍정적으로 생각하는 것을 알 수 있었다. 또한 화훼상품의 이미지가 보정효과로 다듬어진 것이라고 인식하였으나, 실제 상품과 비슷할 것이라고 생각하는 경향을 보였다. 화훼상품 구매결정에 영향을 미치는 이미지 특성으로는 전체적인 분위기가 가장 중요하다고 인식하였으며, 절화 화훼상품 이미지에서 꽃다발과 꽃바구니 화훼상품에 따라 선호하는 배경에 약간의 차이가 나타났다. 구도에 따른 선호도는 꽃다발과 꽃바구니 모두 정면에서 촬영한 이미지를 가장 선호하였으며, 이미지 보정에 대한 선호도에서는 밝은 느낌의 채도가 높은 이미지를 가장 선호하는 반면, 어두운 느낌의 이미지는 선호하지 않는 것으로 나타났다. 화훼상품 이미지 보정효과에 대한 감성인식을 의미변별척도법(semantic differential scale)에 따라 조사한 결과, 채도에 상관없이 밝은 느낌의 이미지는 ‘풍부한’, ‘세련된’, ‘고급스러운’, ‘기품 있는’과 같이 긍정적인 감성어휘 쪽이 높은 것으로 나타났다. 반면 어두운 느낌의 이미지는 전반적으로 부정적인 감성어휘 쪽이 높은 것으로 나타났다. 화훼상품 이미지의 배경, 구도, 보정효과에 따라 소비자의 선호도와 감성반응에 차이가 나타났으나, 소비자의 성별, 연령 및 직업 특성에 따른 유의한 차이는 없었다. 이를 통해, 소비자가 선호하는 이미지를 구축하여 SNS를 통한 화훼상품을 판매하는 것이 소비자들의 구매상품 선택에 도움이 될 것으로 확인되었다.
        4,300원
        2297.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present study was designed to determine the effect of barn or cycle of grazing on changes of biochemical metabolites in prepartum and changes of milk composition in postpartum of dairy cows. For this purpose, a total of sixteen 25 months old Holstein primiparous dairy cows were allocated in two groups (n=8) with an average body weight of 571.61 ± 35.30 kg (Barn) and 578.10 ± 39.20 kg (Grazing). The study was conducted from June 2018 to October 2018. Results revealed that barn raised dairy cows had a higher increase in their serum albumin and calcium level on day 14 prepartum. However, the level of palmitic acid, saturated fatty acid increased significantly, and the level of fat, oleic acid, γ-linoleic acid, arachidonic acid and unsaturated fatty acids decreased significantly in barn raised dairy cow’s milk on day 14 postpartum. There were no significant differences observed with respect to all other biochemical metabolites, fatty acids and minerals between barn raised and cycle grazing dairy cows during prepartum and postpartum. Our study results could serve to a better understanding of barn raised cow with respect to changes of biochemical metabolites in prepartum and changes of milk composition, fatty acids and minerals content in grazing dairy cows in postpartum for estimating their physiological status.
        4,000원
        2298.
        2019.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The purpose of study was to investigate university students’ attitudes towards English language learning apps and examine whether there is any significant difference in their attitudes depending on their personal variables such as their gender, major, grade, nationality, and so on. This study also explored students’ perceptions of English language learning apps that they have used. Participants were college students living in Korea and China. Data were collected by means of a questionnaire and an interview. Results showed that both Korean and Chinese students generally held positive attitudes towards English language learning apps, although Chinese students showed more positive attitudes than Koreans. The main reasons that they liked to use English language learning apps were their convenience, ubiquity, and rich resources. On the other hands, it was revealed that the lack of communication and feedback was the main problem of using such apps. Both Korean and Chinese students stated that it was an effective way to use English language learning apps to practice pronunciation, vocabulary, listening, and reading skills. Findings of this research suggest that English language learning apps should be developed to inspire users/students’ learning interest and foster learner autonomy.
        5,500원
        2299.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Reliability analysis of the components frequently starts with the data that manufacturer provides. If enough failure data are collected from the field operations, the reliability should be recomputed and updated on the basis of the field failure data. However, when the failure time record for a component contains only a few observations, all statistical methodologies are limited. In this case, where the failure records for multiple number of identical components are available, a valid alternative is combining all the data from each component into one data set with enough sample size and utilizing the useful information in the censored data. The ROK Navy has been operating multiple Patrol Killer Guided missiles (PKGs) for several years. The Korea Multi-Function Control Console (KMFCC) is one of key components in PKG combat system. The maintenance record for the KMFCC contains less than ten failure observations and a censored datum. This paper proposes a Bayesian approach with a Dirichlet mixture model to estimate failure time density for KMFCC. Trends test for each component record indicated that null hypothesis, that failure occurrence is renewal process, is not rejected. Since the KMFCCs have been functioning under different operating environment, the failure time distribution may be a composition of a number of unknown distributions, i.e. a mixture distribution, rather than a single distribution. The Dirichlet mixture model was coded as probabilistic programming in Python using PyMC3. Then Markov Chain Monte Carlo (MCMC) sampling technique employed in PyMC3 probabilistically estimated the parameters’ posterior distribution through the Dirichlet mixture model. The simulation results revealed that the mixture models provide superior fits to the combined data set over single models.
        4,000원
        2300.
        2019.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This paper examined the use of assessment techniques in extensive reading and students’ and teachers’ perceptions on the practice of extensive reading. A total of 232 university students who were placed at different proficiency levels of classes and 13 professors participated in the study by completing a questionnaire. In-depth interviews were carried out with a selected number of student and professor volunteers. Data were analyzed using t-tests to compare two different groups of students. Results revealed that writing short answers and assessments involving discussion with peers and professor were utilized more at the basic level, but students at the basic level reported discussion with peers and professor as the most effective assessment technique. In contrast, at the intermediate level, multiple-choice questions and T/F statements were used more as assessments, but students at the intermediate level reported that writing one’s opinion on themes was the most effective technique. Both groups believed that reading graded readers is helpful in improving reading skills and vocabulary as well as understanding other cultures. Results further revealed that professors preferred to use writing short-answer questions and in-class discussion as assessments on graded readers; however, they responded that a writing task was the most adequate type of assessment. In addition, they reported that graded readers are helpful in improving all language skills and favored the use of graded readers as part of the language program.
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