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        검색결과 1,037

        101.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study examined the effect of ultraviolet (UV) application on bacterial disinfection in a commercialized humidifier using ultrasonic wave (UW). To accurately examine disinfection kinetics in tap-water condition, tap-water was sterilized using a filter, and then inoculated with pure cultures of E. coli and P. putida with known viable counts. The disinfection kinetic characteristics were experimentally compared when UV alone, UW alone, and UW+UV together were applied in disinfecting the added bacteria in the commercialized humidifier. When UV alone was applied, bacterial disinfection kinetics followed a first-order decay reaction, and showed an approximately 10-time weaker disinfection compared to the typical UV disinfection in water treatment or wastewater treatment. When UW alone was applied, bacterial disinfection kinetics followed a second-order decay reaction with a low disinfection rate constant of 0.0002 min-1(CFU/mL)-1. When UV and UW were applied together, however and interestingly, the disinfection rate constant (0.0211 min-1(CFU/mL)-1) was approximately 100 times increased than that for the UW alone case. These results revealed that the co-use of UV and UW can provide synergistic effect on bacterial disinfection in a tap-water condition in household humidifiers.
        4,000원
        102.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to determine the effect of horse manure compost application on Italian ryegrass (IRG) yield and volcanic ash soil characteristics. Because the number of horses in Korea is growing, the amount of horse manure is growing. Jeju island, where about 55 % of the horses live, is composed of volcanic ash soil. This study was conducted for about 7 months. Sowing was conducted on October 2019. Harvesting was conducted at heading stage(2020.5.). Five treatments were established based on the horse manure compost composition. These were 100 % chemical fertilizer (CF), the combination of 50 % horse manure and 50 % chemical fertilizer (combination), horse manure with 50 % nitrogen (HM 50 %), horse manure with 100 % nitrogen (HM 100 %), and horse manure with 150 % nitrogen (HM 150 %). The plant height and dry matter yield were investigated to determine the forage yield and the soil characteristics of pH, total nitrogen, available phosphate, and organic matter were analyzed. The plant heights in the CF, combination, and HM 150 % treatments were 147.8 cm, 144.3 cm, and 147.1 cm respectively (Table 2). Dry matter yield in the CF treatment was about 23,807 kg/ha, which tended to be the highest dry matter yield. HM 150 % and the combination treatment were about 18,804 and 18,455 kg/ha, respectively, which tended to be the highest dry matter yield of the treatments amended with horse manure compost. The dry matter yield of the HM 100 % and HM 50 % treatments was about 15,801 kg/ha and 14,446 kg/ha, respectively (Table 2). The pH of the surface soil tended to increase after the experiment. The soil pH of the HM 150 % treatment was significantly higher than the soil pH of the other treatments. The pH was affected by the amount of horse manure compost, with a pH of 8.1. The available phosphate in the treatments in which horse manure compost was added was higher than the available phosphate in the CF treatment. And the available phosphate in the HM 150 % treatment was significantly higher than the available phosphate in the other treatments (p < 0.05)(Table 3). These results suggest that 50 % horse manure should be applied to IRG as the basal fertilizer and the remaining 50 % should be chemical fertilizer as the top fertilizer. This can provide the proper IRG dry matter yield with less effect on volcanic ash soil.
        4,000원
        103.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 한우 암소와 씨수소의 육종가를 기반으로 연도별 유전적 개량량을 추정하여 현재 한우 축군의 개량 정도를 파악하여 향후 한우 개량 방향을 위한 기초자료로 활용하고자 본 연구를 시행하였다. 본 연구를 위하여 한우농가 4,040호에서 축산물품질평가원에 도축된 970,567두의 도축자료를 이용하여 10번 반복되어 추출된 표본 자료와 한우농가에서 2009년부터 2019년까지 사육되고 도축된 개체 중에서 한국종축개량협회에 혈통등록 되어 있는 거세우를 선별하여 결측치 및 이상치를 제거하고 도축월령이 27~32개월 이외의 기록은 분석에서 제외한 후, 1,391,141두의 도체 자료를 분석에 이용하였다. 이용된 형질은 도체중(Carcass Weight, CW), 등심단면적(Eye Muscle Area, EMA), 등지방두께(Backfat Thickness, BF) 및 근내지방도(Marbling Score, MS)의 4개 형질을 고려하였다. Random Sampling 10 반복되어 추출된 Data 1의 도체중, 등심단면적, 등지방두께 및 근내지방도의 개량추세에 대한 회귀계수는 매년 평균 0.44㎏, 0.197㎠, -0.051㎜ 및 0.034점으로 나타났으며, 도축성적을 보유한 전체 개체의 자료로 구성된 Data 2에서는 각각 0.35㎏, 0.22㎠, 0.06㎜ 및 0.04점의 개량추세를 보였다. Data 2에서 씨수소의 개량추세는 1.54㎏, 0.343㎠, -0.045㎜ 및 0.050점의 추세를 보였으며 암소와 씨수소 간에는 1.19㎏, 0.119㎠, -0.014㎜ 및 0.010점의 차이를 보였다. 유전적 개량량을 확인하기 위하여 육종가의 표준편차를 이용하였으며, 암소의 선발강도는 본 연구에서 보고한 암소의 후대 거세우 기록 빈도 및 비율을 통해 계산하였다. 한우 암소의 선발 시기를 3산차 이전을 기준으로 하는 것과 4산차 이후를 기준으로 하는 것으로 나눠서 선발강도를 적용하였다. 그 결과, 암소의 선발 시기를 3산차 이전으로 했을 때 세대당 유전적 개량량은 도체중, 등심단면적, 등지방두께 및 근내지방도에서 각각 5.04㎏, 1.31㎠, 0.71㎜ 및 0.32점으로 나타났다. 이러한 결과를 바탕으로 현재 한우 암소집단에서 정확한 육종가를 추정하고, 유전적 개량량을 높이기 위해서는 후대의 기록을 높이기 위한 육종 계획이 필요할 것으로 판단된다.
        4,000원
        110.
        2021.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 가로수로 식재 한 메타세쿼이아 214본을 대상으로 시각적 활력 평가와 형성층전기저항계(JunsMeter) 측정 결과를 비교하였다. 시각적 활력 평가로 경북 예천군에서는 모든 활력 단계를 관찰하였고, 상주시에서는 ‘매우 양호’와 ‘양호’ 단계만 나타났다. JunsMeter의 측정 평균값은 예천(75.48)보다 상주(86.99)에서 높았다(P=0.01). 방위별 JunsMeter 측정에서는 예천군의 서쪽(71.29)에서 가장 낮았다. 예천과 상주에서 시각적 활력 평가로 구분한 3개 그룹과 JunsMeter 측정값과 일관되게 나타났다.
        4,000원
        112.
        2021.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 고등학생의 자아존중감, 분노표현, SNS중독경향성의 정도 및 그들 변수 간의 관계와 SNS중독경향성에 미치는 영향 요인을 알아보고자 하는 서술적 조사연구이다. 대상자는 2020년 5월 18일~28일까지 총 10일 간 S시, G도 고등학교에 재학 중이며 SNS을 이용하고 있는 대상자에게 온라인 설문지를 이용하여 총 100부의 자료를 수집하였다. 연구결과, SNS중독경향성과 자아존중감(r=-.385, p<.001), 분노조절(r=-.354, p<.001)과는 보통의 역 상관관계, 분노표출(r=.321, p=.001), 분노억압(r=.308, p=.002)과는 보통의 순 상관관계를 나타냈다. SNS중독경향성에 미치는 영향 요인은 자아존중감(β =-.297, p=.001), 성별(β=.266, p=.003), 분노표출(β=.247, p=.007) 순으로 회귀모형의 설명력은 27.7% 로 나타났다(F=12.279, p<.001). 따라서 SNS중독경향성을 낮추기 위해 고등학생의 자아존중감을 높이고 분노표출을 낮추기 위한 프로그램 개발이 필요하며 특히 성별에서 여자 고등학생의 SNS중독경향성을 낮추기 위한 방안이 모색되어야 할 것이다.
        4,200원
        113.
        2021.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to determine the optimal digestible energy levels on pregnancy mares. Physical changes and fecal microorganism in pregnant horse and changes in birth characteristics of neonatal foals were investigated. The experiment was conducted by 18 mares (Jeju corssed bred, older than 36 months) into three treatment groups. The experimental diet consisted of 80%, 100%, 120% digestible energy levels based on NRC. The average daily intake was lower in the 120% (8.75±1.01) than the 100% (9.34±0.92), 80% (9.14±0.88) and there was significant difference (p<0.05). The feed efficiency was lower in the 120% than 80%, 100% (p<0.05). Total cholesterol, HDL-cholesterol, LDL-cholesterol and triglyceride was higher in 120% than others (p<0.05). However there were no health problem and there was no difference between the treatment groups in the birth characteristics of neonatal foals. At the phylum level, Fibrobactres was difference by digestible energy levels, 80% (8.53%) was higher than 100%, 120%. At the genus level, Bacteroides and Kineothrix increased in fecal proportions with increasing digestible energy levels (p<0.05). Fibrobacter showed higher composition at 80% than 100% and 120% (p<0.05).
        4,000원
        114.
        2021.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, a manganese catalyst on the surface of a ceramic support was developed for the removal of odor emitted from barbecuing restaurants. Its ozone oxidation at room temperature was tested using acetaldehyde (CH3CHO), the most dominant compound in the barbecuing odor, and the ozonation efficiency under wet conditions was also studied. The manganese catalyst was made with the honeycomb-type ceramic support, and an acid pretreatment was applied to increase its specific surface area, resulting in an increase of the degree of dispersion of manganese oxide. The acetaldehyde removal efficiency using the manganese catalyst on the acidpretreated support (Mn/APS) increased by 49%, and the ozone decomposition rate and the CO2 conversion rate also increased by 41% and 27%, respectively. The catalyst without surface pretreatment (Mn/S) showed a low efficiency for the acetaldehyde ozonation, and other organic compounds such as acetic acid (CH3COOH) and nonanal (CH3(CH3)7CHO) were found as oxidation by-products. In comparison, CO2 was the most dominant product by the ozonation of acetaldehyde using the Mn/APS. When the relative humidity was increased to 50% in the influent gas stream, the acetaldehyde removal efficiency using the Mn/APS decreased, but only the production rates of CO2 and acetic acid were changed. As a result, the manganese oxide catalyst on the surface of the acid-pretreated honeycomb support manifested high acetaldehyde ozonation even at humid and room temperature conditions.
        4,000원
        115.
        2021.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this study is to identify the emission characteristics of VOCs from small-scale painting facilities, such emissions being pollutants that impact nearby living areas and to devise improvement measures to enhance management plans regarding pollutant emissions from painting facilities. VOCs emissions from painting facilities were estimated according to Clean Air Policy Support System (CAPSS) data based on the National Institute of Environmental Research (NIER)'s emission list in 2017. Three automotive painting facilities in Seoul were chosen for evaluation of the adsorption system. We analyzed the characteristics of VOCs generated by type of different operation and measured the removal efficiency of the adsorption system. Therefore, we analyzed current emissions of VOCs from automotive painting facilities based on field measurements. According to such detailed analysis, a systematic management plan was proposed.
        4,300원
        116.
        2021.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Previous studies have reported that deep neck flexor (DNF) exercise can improve neck problems, including neck pain, forward head posture, and headache, by targeting the deep and superficial muscles of the neck. Despite the prevailing opinion across studies, the benefits of DNF can vary according to the type of neck problems and the outcome measures adopted, ranging from positive outcomes to non-significant benefits. A meta-analysis was conducted in this study to assess conclusive evidence of the impact of DNF exercise on individuals with neck problems. We used PUBMED, MEDLINE, NDSL, EMBASE, and Web of Science to search for primary studies and the key terms used in these searches were “forward head posture (FHP),” “biofeedback,” “pressure biofeedback unit,” “stabilizer,” “headache,” and “neck pain.” Twenty- four eligible studies were included in this meta-analysis and were coded according to the type of neck problems and outcome measures described, such as pain, endurance, involvement of neck muscle, craniovertebral angle (CVA), neck disability index (NDI), cervical range of motion (CROM), radiographs of the neck, posture, strength, endurance, and headache disability index. The overall effect size of the DNF exercise was 0.489. The effect sizes of the neck problems were 0.556 (neck pain), –1.278 (FHP), 0.176 (headache), and 1.850 (mix). The effect sizes of outcome measures were 1.045 (pain), 0.966 (endurance), 0.894 (deep neck flexor), 0.608 (superficial neck flexor), 0.487 (CVA), 0.409 (NDI), and 0.252 (CROM). According to the results of this study, DNF exercise can effectively reduce neck pain. Thus, DNF exercise is highly recommend as an effective exercise method for individuals suffering from neck pain.
        4,000원
        117.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        적외선 유도 무기 체계의 발달로 항공기의 생존성은 지속적으로 위협받고 있으며, 항공기의 생존성을 향상시키기 위한 적외선 스텔스 기술 관련 연구가 진행되고 있다. 본 논문에서는 적외선 유도 미사일이 항공기와 배경 간의 대비 신호를 탐지하는 것에 주목하여 비행 조건에 따른 항공기의 최적 적외선 신호를 분석하고자 하였다. 이를 위해 항공기의 비행 조건을 고려하여 유동 해석과 대류, 전도, 복사 3차원 열전달 해석을 수행하였고, 동체 표면 온도를 도출하여 항공기 주변 유동 특성을 기반으로 항공기의 적외선 신호를 분석하였다. 더 나아가, 비행 조건 별로 최적 적외선 신호를 갖기 위한 최적 방사율을 도출하였고, 비행 조건 별로 최적 방사율을 동체 표면에 적용했을 때 적외선 신호 저감 효과를 분석하였다.
        4,000원
        118.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to investigate the growth characteristics of the shoot and roots and to analyse the morphological characteristics of roots of waterlogging resistant and susceptible maize inbred lines. Six maize inbred lines were treated with waterlogging for 10 days at V3, and the degree of leaf senescence was evaluated for waterlogging resistance. As a result of waterlogging resistance evaluation, KS85 was the most damaged inbred line with 3.33 senescence leaves and 5.54 degree, and KS141 was the least damaged inbred line with 1.33 senescence leaves and 3 degree. At 20 days after treatment, the effect of waterlogging stress on the shoot dry matter accumulation of KS85 and KS141 were decreased by 86.1% and 77.0%, respectively, compared to the control. Similarly, root dry matter accumulation of KS85 and KS141 were decreased by 77.6% and 65.0%. As a result of SEM photographs of the nodal roots of the two maize inbred lines, the thickness of cortex of KS141 was thicker than that of KS85, and the distortion of the cortex was observed in KS85 at 20 days after waterlogging. It was concluded that the thickness of cortex was related to maize waterlogging resistance.
        4,000원
        119.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This experiment was conducted to investigate the effects of feeding TMR(Total Mixed Ration) with Sasa quelpaertensis Nakai of Jeju cross-bred horses on the body weight and blood composition. Fourteen herds of Jeju cross-bred horses older than 36 months were selected as experimental animals. The experiment was conducted by dividing the herds into seven herds for feeding TMR with 20% Sasa quelpaertensis Nakai(treatment) and another seven herds for feeding TMR without Sasa quelpaertensis Nakai(control) and water were fed ad libitum. In the 12th week, the MPV(mean platelet volume) was statistically significantly higher with Sasa TMR than with control (p<0.05). However, both MPV levels are within a normal range and there were no health problems. With regard to the levels of cholesterol, there was a statistically significant difference between the 33.8±5.9 ㎎/㎗ with individual management and 25.4±8.2 ㎎/ ㎗ with control group (p<0.05). But It are also within a normal range and there were no health problems. In conclusion, feeding TMR with 20% Sasa quelpaertensis Nakai of Jeju cross-bred horses could be utilized as a feeding method for horse.
        4,000원
        120.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 한우농가에서 직접 사육되어 도축되어진 한우 거세우 전체의 도축성적 및 혈통자료를 수집하여 한우 암소의 유전능력평가를 위한 유전모수를 추정하고 농가에서 직접적으로 활용 가능한 유전능력 추정을 위한 기초자료로 제공하고자 하였다. 본 연구를 위해 검증된 970,141두의 도축기록으로부터 60,000두 이상의 표현형 표본을 추출하기 위해 전체 4,040농가 중 600농가를 단순임의추출(Simple Random Sampling)하여 선정된 농가의 도축기록을 모두 추출하는 방식으로 10회 반복하여 표본을 생성하였다. 본 연구에서 추정된 도체형질에 대한 유전력은 도체중에서 0.24-0.30, 등심단면적에서 0.24-0.31, 등지방두께에서 0.31-0.39, 근내지방도에서 0.38-0.58로 추정되었으며, 10회 반복 추정된 유전력의 평균값은 도체중, 등심단면적, 등지방두께 및 근내지방도에서 각각 0.28, 0.28, 0.35 및 0.48로 추정되었다. 추정된 결과가 기존에 한우에서 보고된 유전력에 비해 다소 낮게 추정되었으나 실제 농가에서 사육되어 도축된 전체 자료가 표본이 된 만큼 본 연구 결과는 전국단위의 도축자료를 이용한 결과로서 암소개량을 위해 직접적으로 활용 가능한 자료가 될 수 있을 것으로 기대된다.
        4,000원