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        검색결과 7,607

        21.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Effects of glutamic acid (Glu) and monosodium glutamate (MSG) on oxidative stability of oil-in-water (O/W) emulsions with different emulsifier charges during riboflavin (RF) photosensitization were evaluated by analyzing headspace oxygen content and conjugated dienes. Cetyltrimethylammonium bromide (CTAB), Tween 20, and sodium dodecyl sulfate (SDS) were used as cationic, neutral, and anionic emulsifiers, respectively. Glu acted as an antioxidant in CTAB- and Tween-20-stabilized O/W emulsions during RF sensitization, whereas Glu acted as prooxidants in SDS-stabilized O/W emulsions in the dark. However, adding MSG did not have a constant impact on the degree of oxidation in O/W emulsions irrespective of the emulsifier charge. In RF-photosensitized O/W emulsions, the emulsifier charge had a greater influence on antioxidant properties of Glu than on those of MSG.
        4,000원
        22.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문은 회분식 반응기에서 습식 산화법으로 합성한 칼륨 페레이트(VI)에 의한 난분해성 아조 염료Reactive Black 5의 분해 과정을 연구하는 것을 목적으로 한다. 수용액에서 RB5의 분해는 pH, Ferrate (VI) 투입량, 초기 농도, 수용액 온도 등 다양한 변수의 조건에서 연구되었다. RB5 경우에는 최대 분해 효율은 pH 7.0에서 63.2%가 달성되었으며, 이 실험 조건에서 얻은 kapp 값은 190.49 M-1s-1 으로 나타났다. 온도 또한 가장 중요한 매개 변수 중 하나로 연구되었으며, 그 결과로부터 온도(45°C까지)를 증가시키면 페레이트(VI)에 의한 아조 화합물 염료의 분해 효율이 증가하고, 온도가 45°C를 초과하면 분해 효율이 저하되는 것으로 나타났다.
        4,200원
        23.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study explores the profound impact of varying oxygen content on microstructural and mechanical properties in specimens HO and LO. The higher oxygen concentration in specimen HO is found to significantly influence alpha lath sizes, resulting in a size of 0.5-1 μm, contrasting with the 1-1.5 μm size observed in specimen LO. Pore fraction, governed by oxygen concentration, is high in specimen HO, registering a value of 0.11%, whereas specimen LO exhibits a lower pore fraction (0.02%). Varied pore types in each specimen further underscore the role of oxygen concentration in shaping microstructural morphology. Despite these microstructural variations, the average hardness remains consistent at ~370 HV. This study emphasizes the pivotal role of oxygen content in influencing microstructural features, contributing to a comprehensive understanding of the intricate interplay between elemental composition and material properties.
        4,000원
        24.
        2024.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer (SPHEREx) will provide all-sky spectral survey data covering optical to mid-infrared wavelengths with a spatial resolution of 6.′′2, which can be widely used to study galaxy formation and evolution. We investigate the galaxy-galaxy blending in SPHEREx datasets using the mock galaxy catalogs generated from cosmological simulations and observational data. Only ∼0.7% of the galaxies will be blended with other galaxies in all-sky survey data with a limiting magnitude of 19 AB mag. However, the fraction of blended galaxies dramatically increases to ∼7–9% in the deep survey area around the ecliptic poles, where the depth reaches ∼22 AB mag. We examine the impact of the blending in the number count and luminosity function analyses using the SPHEREx data. We find that the number count can be overestimated by up to 10–20% in the deep regions due to the flux boosting, suggesting that the impact of galaxy-galaxy blending on the number count is moderate. However, galaxy-galaxy blending can marginally change the luminosity function by up to 50% over a wide range of redshifts. As we only employ the magnitude limit at Ks-band for the source detection, the blending fractions determined in this study should be regarded as lower limits.
        4,000원
        25.
        2024.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        A force-free field (FFF) is determined solely by the normal components of magnetic field and current density on the entire boundary of the domain. Methods employing three components of magnetic field suffer from overspecification of boundary conditions and/or a nonzero divergence-B problem. A vector potential formulation eliminates the latter issue, but introduces difficulties in imposing the normal component of current density at the boundary. This paper proposes four different boundary treatment methods within the vector potential formulation. We conduct a comparative analysis of the vector potential FFF solvers that we have developed incorporating these methods against other FFF codes in different magnetic field representations. Although the vector potential solvers with the new boundary treatments do not outperform our poloidal-toroidal formulation code, they demonstrate comparable or superior performance compared to the optimization code in SolarSoftWare. The methods developed here are expected to be readily applied not only to force-free field computations but also to time-dependent data-driven simulations.
        4,300원
        26.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Most studies targeting stroke patients have confirmed improvements in balance and walking using immersive and non-immersive virtual reality training programs. However, to date, there are not many studies targeting brain activation enhancement for the two training programs. Objectives: The purpose of this study is to investigate the effect of a virtual reality training program on the EEG of stroke patients according to differences in immersion. Design: A randomized controlled trial. Methods: A total of 20 stroke patients, with 10 in an immersive virtual reality training programs group (IVRG) and 10 in a non-virtual reality training programs group (NVRG) were randomly assigned to exercise three times a week for 6 weeks. EEG was measured for 2 minutes using DSI-24. Results: The intra-group difference in relative alpha waves of brain waves was not significant for both groups, and the between-group difference was not significant. Differences in EEG relative beta waves in the experiment group were significant in the Fp1, Fp2, Cz, C3, C4, P3, and O2 in the experiment group, and significant in the Cz and O2 in the control group. As a result of comparing the differences between each group before and after, there was a significant difference in the Fp1 area. Conclusion: Virtual reality training programs based on differences in immersion were found to have a positive effect on EEG. Therefore, it is believed that a virtual reality training program based on differences in immersion can be provided as a clinical intervention method for EEG.
        4,500원
        27.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: The Nordic hamstring exercise is effective as a representative exercise for strengthening eccentric contraction that can activate the hamstring at high levels, improve eccentric contraction strength and ability, and significantly reduce injury rates. Objectives: To investigated a comparison with the lunge exercise to determine the effect of the Nordic hamstring exercise on muscle activity and balance ability in a sample of adult amateurs and football players. Design: Randomized controlled trials. Methods: The subjects of the study were stratified samples of 28 professional and amateur football players and two groups (Nordic hamstring group and lunge group) of 14 people each were studied. Surface electromyography using, was performed to measure the hamstring muscle activity, and the good morning exercise was selected as the measurement exercise. For balance ability, the surface area ellipse and length were measured with BioRescue, while for static balance, the posture of closing the eyes and single-limb standing was measured, and for dynamic balance the one-legged squat was measured. Results: The %MVIC of the semitendinosus and the biceps femoris improved in the Nordic hamstring exercise group and showed statistically significant increase (P<.05). The static and dynamic balance improved in the Nordic hamstring exercise group and showed statistically significant decrease (P<.05). Conclusion: The Nordic hamstring exercise can be useful as an exercise to improve the hamstring muscle activity and balance ability of professional and amateur football players.
        4,200원
        28.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        해사영어는 선박 운항, 해양 안전, 선내 의사소통 및 선외 교신을 위해 설계된 특수한 영어 언어체계이다. 국제해사기구 STCW(선원의 훈련, 자격증명 및 당직근무의 기준에 관한 국제협약)에 따르면 국제항해에 종사하는 항해사가 되기 위해서는 SMCP를 포함한 해사영어 대한 충분한 이해가 수반되어야 한다. 본 연구는 음성인식, 번역, 단어 기입 등 유형의 해사영어시험을 통하여 학생들 의 해사영어 활용 능력을 측정하고 플랫폼 사용에 따른 시험 점수 향상 정도, 나아가 초임항해사로 나가기 위하여 요구되는 해사영어 시험 플랫폼 활용 시간 등을 조사하고자 하였다. 실험은 먼저 초기 시험을 통해 학생들의 일반영어능력과 SMCP 활용 능력에 대한 연 관성을 조사한 후, 중간 시험 및 최종 시험을 통해 플랫폼 활용에 대한 점수 향상 정도, 응시시간 변화 등 요인을 측정하였다. 초기 시 험을 통해 개인 요인(예: 토익 점수, 본인 스스로에 대한 영어능력 평가)에 따른 그룹 간 해사영어시험 점수에 유의한 차이가 있음을 확인하였으며, 중간시험 및 최종시험을 통해 플랫폼 활용이 유의한 시험점수 향상으로 이어졌음을 확인하였다. 해당 연구는 해사 교육 분야에 다양하게 적용할 수 있는 학습 플랫폼 활용 효능을 조사하였으며 향후 해사영어 교육 외 그 범위를 넓혀 활용될 수 있을 것으 로 사료된다.
        4,000원
        29.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to analyze the formative characteristics of women’s costumes among the Regency era’s elite in the television drama Bridgerton (2020). Its methodology investigates the socio-cultural background and literature on clothing in the Regency era. It also analyzes the formative elements of Daphne’s costumes (of the Bridgerton family) and Penelope’s costumes (of the Featherington family) representing the upper class. The study reveals that women’s costumes had a tubular silhouette consisting of a low neckline, high waistline, and short puffed sleeves. The series expressed well the Regency-era costumes, which were influenced by Neoclassicism and characterized by silk materials, shawls, gloves, belts, a reticule, and hairstyles. Among the formative elements, the Bridgerton and Featherington families’ costumes showed distinct differences in color, materials, patterns, accessories, and hairstyles. Daphne’s costumes were intelligent and elegant in pastel-toned blues and had small patterns. She carried small accessories and had a natural curled hairstyle. In contrast, Penelope wore decorative and splendid styles in intense colors and large patterns. Her accessories were large and colorful, and she had a strong curled hairstyle. These costumes express the Bridgerton family as aristocratic and the Petringer family as flashy, thereby distinguishing the two families. These research results will be presented as basic data for producing drama costumes in the 19th century to help complete the drama.
        4,500원
        30.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Along with other heavy metals, arsenic (As) is one among the substances most harmful to living organisms including humans. Owing to its morphological similarity to phosphorus, the uptake of As is influenced by photosynthesis and the phosphorus uptake pathway. In this study, we varied arsenic exposure and light intensity during nutrient solution cultivation of lettuce (Lactuca sativa L.) to determine the effect of these two factors on arsenic uptake, lettuce growth, and electron transfer in photosystem II. In the treatment exposed to 30 μmol L-1 of arsenic, the shoot arsenic concentration increased from 4.73 mg kg-1 to 18.97 mg kg-1 as the light intensity increased from 22 to 122 μmol m-2 s-1. The water content and ET2o/RC of the shoots were not affected by arsenic at low light intensity; however, at optimal light intensity, they decreased progressively with arsenic exposure. Increased light intensity stimulated the growth of plant roots and shoots; contrarily, the difference in growth decreased as the concentration of As exposure increased. The results of this study suggest that the effect of As on plant growth is dependent on light intensity; in particular, an increase in light intensity can increase the uptake of As, thereby affecting plant growth and As toxicity.
        4,000원
        31.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Hypertension is characterized by excessive renin-angiotensin system activity, leading to blood vessel constriction. Several synthetic compounds have been developed to inhibit renin and angiotensin-converting enzyme (ACE). These drugs often have adverse side effects, driving the exploration of plant protein-derived peptides as alternative or supplementary treatments. This study assessed the phenolic compound and amino acid content and the antioxidant and antihypertensive activity of 5 South Korean staple crops. Sorghum had the highest phenolic compound content and exhibited the highest antioxidant activity. Millet grains, particularly finger millet (38.86%), showed higher antihypertensive activity than red beans (14.42%) and sorghum (17.16%). Finger millet was found to contain a large proportion of branched-chain, aromatic, and sulfur-containing amino acids, which are associated with ACE inhibition. In particular, cysteine content was positively correlated with ACE inhibition in the crops tested (r=0.696, p<0.01). This study confirmed that the amino acid composition was more correlated with the antihypertensive activity of grains than the phenolic compound content. Finger millet mainly contained amino acids, which have higher ACE inhibitory activity, resulting in the strongest antihypertensive activity. These findings underscore the antihypertensive potential of select crops as plant-based food ingredients, offering insight into their biological functions.
        4,200원
        32.
        2023.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This comprehensive study delves into the intricate process of exfoliating and functionalizing boron nitride nanosheets (BNNSs) extracted from hexagonal boron nitride (h-BN), and meticulously explores their potential application within epoxy composites. The extensive research methodology encompasses a sequence of treatments involving hydrothermal and sonication processes aimed at augmenting the dispersion of BNNSs in solvents. Leveraging advanced analytical techniques such as Raman spectroscopy, X-ray diffraction, and FTIR spectroscopy, the study rigorously analyzes a spectrum of changes in the BNNS’s properties, including layer count variations, interlayer interactions, crystal structure modifications, and the introduction of functional groups. The research also rigorously evaluates the impact of integrating BNNSs, specifically glycidyl methacrylate (GMA)-functionalized BNNSs, on the thermal conductivity of epoxy composites. The conclusive findings exhibit notable enhancements in thermal properties, predominantly attributed to the enhanced dispersion of fillers and enhanced interactions within the epoxy matrix. This pioneering work illuminates the wide potential of functionalized BNNSs for significantly enhancing the thermal conductivity of epoxy composites, paving the way for advanced materials engineering and practical applications.
        4,000원
        33.
        2023.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        A transfer cask serves as the container for transporting and handling canisters loaded with spent nuclear fuels from light water reactors. This study focuses on a cylindrical transfer cask, standing at 5,300 mm with an external diameter of 2,170 mm, featuring impact limiters on the top and bottom sides. The base of the cask body has an openable/closable lid for loading canisters with storage modules. The transfer cask houses a canister containing spent nuclear fuels from lightweight reactors, serving as the confinement boundary while the cask itself lacks the confinement structure. The objective of this study was to conduct a structural analysis evaluation of the transfer cask, currently under development in Korea, ensuring its safety. This evaluation encompasses analyses of loads under normal, off-normal, and accident conditions, adhering to NUREG-2215. Structural integrity was assessed by comparing combined results for each load against stress limits. The results confirm that the transfer cask meets stress limits across normal, off-normal, and accident conditions, establishing its structural safety.
        4,600원
        34.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present study describes Philodromus paiki sp. nov., which was previously misidentified as P. fuscomarginatus (De Geer, 1778), P. poecilus (Thorell, 1872), and P. spinitarsis Simon, 1895 in Korea, as a new species with diagnosis, detailed descriptions, and taxonomic photographs. Additionally, P. spinitarsis is also described to correct previous misidentifications of Korean records of the species.
        4,000원
        35.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Abstract Purpose : To investigate the prevalence and risk factors for dry eye syndrome (DES) in university students. Methods : A cross-sectional survey of university students was conducted through a combination of online smartphone surveys using Google Forms and face-to-face questionnaires. The questionnaire consisted of questions about risk factors for dry eye disease and the 5-item Dry Eye Questionnaire (DEQ-5). Results : A total of 288 university students participated in the study. The average age was 22.5±2.1 years, w ith 54.2% female a nd 4 5.8% m ale. The m ean of t he D EQ-5 s core w as 7.37±4.65, and the prevalence of DES by DEQ-5 was 47.2%. Female gender (p=0.012), digital screen use for more than 8 hours per day (p=0.018), digital screen use for more than two hours without a break (p=0.035), contact lens wear (p=0.016), refractive surgery (p=0.020), less than 6 hours of sleep per night (p=0.0169, and allergic conjunctivitis (p=0.016) were relevant associated risk factors for DES. Conclusion : The prevalence of DES in young adults may be underestimated in comparison to middle-aged and older adults. The severity of DES depends on several factors, including genetic and environmental factors, so identifying risk factors would help with proper prevention and early diagnosis. Key words : DEQ-5, Dry eye syndrome, Risk factor
        4,000원
        36.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Abstract Purpose : To investigate the effect of the amount of astigmatism on distance and near vertical heterophoria in adults aged 20~40 years. Methods : Thirty subjects (31.25±10.21 years) were participated, and refraction was performed using I-Profilerplus and a phoropter, and horizontal heterophoria (HH) and vertical heterophoria (VH) teats were conducted at distance and near using a Torrington chart. Results : HH and VH were approximately 0.80 △ (p=0.001) and 0.20 △ (p=0.002) greater at near than at distance, respectively. Spherical refractive errors did not correlate with HH and VH at distance and near. There was no correlation between astigmatism and HH at either distance or near (p=0.141, p=0.318, respectively), but VH at distance and near was significantly correlated with astigmatism (both, p < 0.001), the amount of VH increased with increasing the amount of astigmatism. Conclusion : We found that the amount of astigmatism affected the VH at both distance and near and that the amount of VH increased with increasing astigmatism. These findings suggest that it is important to assess both astigmatism and VH in clinical practice, and that correction of astigmatism may help to reduce symptoms of VH. Key words : Astigmatism, Horizontal heterophoria, Refractive error, Vertical heterophoria
        4,000원
        37.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Abstract Purpose : The distribution of axial length and ocular dimensions was investigated, and each correlation according to gender and age was investigated. Methods : Among 847 eyes of 438 patients, 207 eyes in 20s, 210 eyes in 30s, 216 eyes in 40s, and 214 eyes in 50s were measured for axial length with IOL-Master 700. Refractive error was measured with KR-800. Corneal curvature radius and corneal eccentricity were measured with Keratograph 4. Results : Axial length (male: 24.57±1.22mm, female: 24.03±1.12mm) and horizontal corneal eccentricity (male: 0.58±0.11, female: 0.54±0.12) tended to increase in decreased age, male and myopia. Mean corneal curvature radius (male: 7.82±0.25mm, female: 7.71±0.25 mm), and horizontal corneal curvature radius (male: 7.91±0.26 mm, female: 7.79±0.26mm), nasal corneal eccentricity (male: 0.68±0.14, female: 0.66±0.15), and temporal corneal eccentricity (male: 0.45±0.14, female: 0.44±0.13) tended to increase in decreased age and male. Mean corneal eccentricity (male: 0.57±0.12, female: 0.54±0.12), vertical corneal curvature radius (male: 7.71±0.27 mm, female: 7.65±0.24 mm), vertical corneal eccentricity (male: 0.56±0.15, female: 0.54±0.15), and inferior corneal eccentricity (male: 0.52±0.19, female: 0.46±0.22) tended to increase in male. The correlation with axial length and corneal curvature radius showed a high correlation in emmetropia and the horizontal. Horizontal and temporal corneal eccentricity showed a low correlation. Conclusion : Axial length, corneal curvature radius, and corneal eccentricity (excluding vertical) were higher in males. As age increased, axial length, and corneal curvature radius decreased. Among the 4 quadrants of corneal eccentricity, only the temporal s ide showed a significant correlation with axial length. Key words : Age, Axial length, Corneal curvature radius, Corneal eccentricity, Gender Authors ORCID:†
        5,500원
        38.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Abstract Purpose : To determine the perceptions of soft contact lens wearers regarding contact lens wear and care, and their knowledge of adverse effects of contact lens wear by self-assessment. Methods : An online survey using smartphone was conducted by Naver and Google questionnaires among university students who have experience wearing soft contact lenses. Results : Two hundred twenty-eight soft lens wearers were participated in the study. The average age was 20.9±1.7 years (female 72.8%; male 27.2%) were university students. Approximately 25.4% of respondents did not receive training and practices for safe soft lens wear and 14.1% evaluated themselves as poor at wearing and caring for soft lenses. The most uncomfortable symptom of soft lens wear was dryness at 76.3%, and 36.0% experienced soft lens-related adverse events. The higher type of adverse event was conjunctivitis, and the most common self-reported cause of contact lens-related adverse events was improper lens care and non-compliance to lens wear regimens. Conclusion : Based on the self-assessment of soft lens care that resulted from this survey, we believe that a more proactive approach to intervention by contact lens practitioners is still needed to prevent the risk of adverse events and improve soft lens wearer behavior. Key words : Compliance, Contact lens-related adverse events, Self-assessment, Soft contact lens Authors ORCID:†
        4,500원
        39.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 한국산 미기록속인 이마줄불청객파리속(신칭)과 미기록종인 작은눈이마줄불청객파리(신칭)를 처음으로 보고한다. 우리는 이 종이 포식성 거미의 섭식과정에 관여하는 phoretic relationship의 습성을 갖는 것을 확인하였다. 이 종의 성충에 대한 기재문과 사진 및 DNA바 코드 서열을 제공한다.
        4,000원
        40.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Abstract Purpose : This study investigated the impact of knowledge and awareness of perception of harmful rays on the use of blue light blocking lenses among university students majoring in optometry. Methods : This study targeted 65 optometry students who responded to an online survey from September 2023 to October 2023. The survey used a survey tool with a total of 15 questions, including knowledge and awareness of perception of harmful rays and demands for guidelines. Statistical analysis was performed using SPSS 19.0. Results : The overall knowledge score about UV rays and blue light was 14.00±3.10 for optometry students and 12.30±3.50 for general university students, showing that the optometry students had higher knowledge (p<0.001). In the case of use of UV-blocking lenses, 70.8% of optometry students were found to be using them, which was higher than 51.5% of general university students. The use of glasses to block blue light was found to be 41.5% of optometry students and 36.9% of general university students. The correlation between perception of the importance of blocking harmful rays and the need for guidelines for the correct selection of blue light blocking lenses was r=0.528 (p<0.001). Conclusion : Optometry students' knowledge and perception of harmful rays were found to be higher than those of general university students, and it appears to have an impact on the use of harmful ray-blocking lenses. Therefore, it is necessary to strengthen education and establish guidelines for the correct selection of harmful ray blocking lenses.
        4,000원
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