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        검색결과 156

        62.
        2018.05 구독 인증기관·개인회원 무료
        Composite pavements are constructed by placing a high functional asphalt surface layer on a high performance concrete rigid base layer and provide a more durable, high functional surface to road users. Service life of composite pavements is dependent on the bonding performance of the lower rigid base and the flexible surface layer. Accordingly, it is necessary to place an impermeability layer between the functional surface layer and the rigid base to enhance bonding performance and to prevent moisture penetration into the rigid base and deterioration of pavement. In order to use optimal composite pavement sections, two types were applied to impermeability layer: highly impermeable water-tight SMA and mastic asphalt currently in use. APT (Accelerated Pavement Testing) and experimental construction were carried out to evaluate bond strengths between the rigid base and the impermeability layer depending on the type of impermeability layers. Composite pavement sections for the APT had a 22 cm concrete rigid base layer and a 5cm functional surface, as well as either 5cm of SMA impermeability layer and 5cm of mastic layer. After applying around 8,574,000 ESALs, pull-off test was conducted, which showed that the mastic section outperformed the SMA section. In the experimental construction, three types of rigid base layers, JCP (Jointed Concrete Pavement), CRCP (Continuously Reinforced Concrete Pavement), and RCCP (Roller Compacted Concrete Pavement), were used for composite pavement sections, and as in the APT, two types of impermeability layers, SMA and mastic, were used per rigid base layer of new and deteriorated concrete pavement. Therefore, seven composite pavement sections in total were constructed. We measured the bond strength over one year or so following the construction of these composite pavement sections and found that regardless of the type of rigid base layer and whether it was new or not, those sections with a mastic impermeability layer had high bond strengths.
        63.
        2018.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this study was to investigate the effects of freeze dried placenta supplementation on reproductive performance, colostrum and plasma biochemical composition in pregnant sows. Eleven Landrace × Large white sows were fed with corn-soybean meal diets supplemented with or without 1% freeze dried placenta powder from 10 days before their expected farrowing dates until 10 days postpartum. The colostrum protein content was significantly higher(P=0.043) in the treatment group than in the control group. Compared to the control group, the immunoglobulin G(IgG) concentration in the colostrum was significantly higher(P=0.004) in the treatment. In day 25 piglets plasma, the IgG concentration was higher(P=0.184) in the treatment than the control. The mortality rate was lower(P=0.102), and the piglet weight gain was higher(P=0.35) in the treated group. Overall, the treatment group showed greater levels of protein and IgG concentration in the colostrum, when compared to control group. Therefore, the freeze dried placenta supplementation on pregnant sows can enhance its colostrum composition, hence decrease the mortality and increase the growth rate of piglets.
        4,000원
        64.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of the study was to investigate the effects of incentive spirometry and Ujjayi breathing technique on the pulmonary function of smokers. Subjects were individuals who had a smoking habit of at least a year. Subjects were randomly divided into 3 groups: the incentive spirometry group (n=8), Ujjayi breathing technique (n=9), and a group applying both incentive spirometry as well as Ujjayi breathing technique (n=8). Each intervention was performed twice a day, 5 times a week, for a total of 8 weeks whereupon the change in pulmonary function was evaluated. A spirometer was used to measure FVC, FEV1, and FEV1/FVC. The survey used for this study included the Fagerström Test of Nicotine Dependence (FTND) and the Shortness of Breath Questionnaire (SOBQ). Study results for the comparison within groups showed that in the group that performed both the incentive spirometry and Ujjayi breathing technique, FEV1 improved with statistical significance (p<.05). Furthermore, within this comparison the FEV1/FVC improved with statistical significance. Comparison amongst the groups showed no statistically significant differences in all areas. Following, to effectively increase pulmonary function in young adult smokers, both incentive spirometry and Ujjayi breathing technique should be employed together.
        4,000원
        65.
        2017.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Salt stress is one of the most limiting factors that reduce plant growth, development and yield. However, identification of salt-inducible genes is an initial step for understanding the adaptive response of plants to salt stress. In this study, we used an annealing control primer (ACP) based GeneFishing technique to identify differentially expressed genes (DEGs) in Italian ryegrass seedlings under salt stress. Ten-day-old seedlings were exposed to 100 mM NaCl for 6 h. Using 60 ACPs, a total 8 up-regulated genes were identified and sequenced. We identified several promising genes encoding alpha-glactosidase b, light harvesting chlorophyll a/b binding protein, metallothionein-like protein 3B-like, translation factor SUI, translation initiation factor eIF1, glyceraldehyde-3-phosphate dehydrogenase 2 and elongation factor 1-alpha. These genes were mostly involved in plant development, signaling, ROS detoxification and salt acclimation. However, this study provides new molecular information of several genes to understand the salt stress response. These genes would be useful for the enhancement of salt stress tolerance in plants.
        4,000원
        67.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 약용식물 추출물을 함유한 숙취해소 음료가 항산화 및 알코올 분해에 미치는 영향을 조사하기 위하여, 약용식물 추출물의 총 페놀성화합물 함량, 총 플라보노이드 함량 및 DPPH radical 소거활성 및 ALDH(aldehyde dehydrogenase) 활성을 측정하였고, 약용식물 추출물을 함유한 숙취해소 음료의 복용이 음주 후 호흡 중 알코올 농도에 미치는 영향을 조사하였다. 항산화활성은 빼빼목 추출물 에서 높은 수치(total phenolic compound 97.5.6mg/g, total flavonoid 306.5mg/g, DPPH radical 소거능 80.1%)를 나타냈으며 Acetaldehyde(ALDH)에 대한 활성은 헛개 및 울금 추출물에서 306% 및 292%로 가장 높은 활성을 나타내어, 헛개 및 울금 추출물이 ALDH 제거에 효과적인 것으로 나타났다. 헛개 및 울금 추출물이 함유된 숙취해소 음료를 이용하여, 임상실험을 실시한 결과, 시간경과에 따라 대조군에 비해 숙취해소음료 섭취군에서 알코올 농도가 감소되는 경향을 나타냈으며 흡연자에 비해 비 흡연자가, 남성에 비해 여성에게 숙취해소 음료의 섭취가 더 효과적인 것으로 확인되었다.
        4,000원
        68.
        2017.04 구독 인증기관·개인회원 무료
        We analyzed the variation in occurrence time and intensity of attacks by the rice stem borer (Chilo suppressalis Walker) on several crops. We found similar occurrence patterns of C. suppressalis in different crops. Overwintering larvae showed no difference in pupal period and weight compared to the non-overwintering ones. However, the larval period was reduced to 19.1 days in Miscanthus field, in contrast to that in the paddy fields. Efficiency of the emergence trap was confirmed to be greater than that of the delta trap for capturing C. suppressalis adults. It is necessary to adjust the control period because of the advancement in occurring time of C. suppressalis in recent years. The larvae of C. suppressalis experience favorable environmental conditions for overwintering in Miscanthus fields. The results of this study provide important inputs for the development of environment-friendly control methods.
        69.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 대추나무 생산농가의 합리적인 생산 계획수립을 지원하는 방안으로 2015년 9월부터 10월 사이에 경북 경산시 과원에서 5~30년생 대추나무의 수령별 과실특성, 수체특성 및 생산량을 조사하였 다. 대추나무 수령에 따른 과실 특성에 있어서, 과실 중량, 과실종경, 과실횡경은 5~25년생에서는 유의 성을 나타내지 않았으나, 30년생에서 감소된 수치를 나타냈고, 과형지수는 수령이 증가할수록 감소되는 경향을 나타냈다. 그러나, 과실당도는 23.28~25.46°Brix 범위로 수령에 따른 유의성이 나타나지 않았 다. 대추나무 수령에 따른 수체특성에 있어서, 수고, 근원경, 수관 폭 및 수관면적은 10년생까지 유의성 을 나타내며 생장하였으나, 10년생부터 30년생까지는 유의성을 나타내지 않았다. 생대추 생산량은 25년 생부터 유의하게 증가하는 경향을 나타내어, 대추나무의 수령이 생대추 생산량에 영향을 미치는 것을 확인하였다. 대추나무 수령이 생대추 생산량에 영향을 미치는 인자를 비교하였으며, 조사된 수체특성 인자에 대하여 상관계수를 도출하였다. 그 결과 생대추 생산량에 가장 큰 영향을 미치는 수체특성 인자 는 수관폭으로 나타났다.
        4,000원
        70.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The efficacy of the natural amendments in improving physical condition as well as waterretention characteristics of the growing media in pot culture was studied on seven different mixratio of growing media applied to soil. Growing media was prepared from peat, perlite, pruningwaste, pulp(3:1:3:3(w/w/w/w)). Growth substrates were prepared by mixing growing media at therates of 0%, 10%, 20%, 30%, 40%, 50% and 100% with soil at 100%, 90%, 80%, 70%, 60%,50% and 0%, respectively. The bulk density tended to decreased with increasing growing mediaproportions. The particle density was lowest(0.6 g/cm3) in sole growing media treatment and theporosity of all the soil mixed growing media(63.2~83.3%) was significantly higher than that ofthe soil as sole medium(60.7%). The water content was lowest in sole soil treatment(5.1%) andgrowing media as sole medium(57.8%) was the closely ideal range for pot culture(>60%). Although substrates were varying water to the atmosphere at similar rates which retained waterfor longer, growing media as sole still remain constant on high water content. It was confirmedthat strongly correlated between bulk density and water retentivity(correlation-0.85).
        4,300원
        71.
        2016.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Populus euramericana is emerging as a viable feedstock for producing bioethanol from renewable resources. Steam explosion pretreatment of P. euramericana can solubilize a significant portion of the hemicellulosic component and enhance the glucose conversion of the remaining cellulose for fermentation into ethanol. In this study, steam explosion condition of P. euramericana is performed in a steam explosion reactor at severity log Ro 4.02 and severity log Ro 4.37. Glucose conversion varied from 72.3% to 80.1% of steam exploded P. euramericana at severity log Ro 4.02 and severity log Ro 4.37. Ethanol yields(%) based on sugar content after enzymatic hydrolysis after 48 h fermentation ranged from 87.0% to 88.4%. As a result, from 100 g of raw material, 14.0 g of ethanol are recovered of 47.3 g available cellulose content. This research of steam explosion pretreatment was a promising method to improve glucose conversion and ethanol yield for bioethanol production.
        4,000원
        73.
        2016.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This experiment was designed to assess the physical and chemical properties of growing media substituted with a range of increasing concentrations of pretreated wood and to relate these properties to plant growth responses. For preparing the growing media, each material was combined with rural soil, peat, perlite and pretreated wood. Physicochemical properties studied were similar to ideal substrate ranges for plant growth on growing media, including pretreated wood. Physical properties were also well maintained over time. In comparison to plants growing in 100% rural soil, tall fescue(Festuca arundinacea) in the prepared growing media achieved better growth, especially when using the 50% rural soil + 50% PPW(peat + perlite + pretreated wood, 3:1:6(w/w/w)) and 30% rural soil + 70% PPW (peat + perlite + pretreated wood, 3:1:6(w/w/w)), and showed improved germination percentage. We confirmed the potential use of growing media, including pretreated wood. Furthermore, our results show a correlation among the physicochemical properties of tall fescue(Festuca arundinacea); physical properties were significantly influenced by germination and aerial parts. The root length of physicochemical properties was correlated with bulk density and organic compound (p<0.01).
        4,000원
        75.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present research investigated copper and cadmium stress-induced differentially expressed genes (DEGs) using annealing control primers (ACP) with the differential display reverse transcription polymerase chain reaction technique in alfalfa (Medicago sativa L. cv. Vernal) leaves. Alfalfa leaves were subjected to 250 μM of copper and cadmium treatment for a period of 6 h. A total of 120 ACPs was used. During copper and cadmium treatment, 6 DEGs were found to be up or down regulated. During copper stress treatment, 1 DEG was up-regulated, and 3 novel genes were discovered. Similarly, during cadmium stress treatment, 1 DEG was up-regulated and 5 novel genes were identified. Among all 6 DEGs, DEG-4 was identified as the gene for trans-2,3-enoyl-CoA reductase, DEG-5 was identified as the gene for senescence-associated protein DIN1 and DEG-6 was identified for caffeic acid O-methyltransferase. All the up-regulated genes may play a role in copper and cadmium stress tolerance in alfalfa.
        4,000원
        76.
        2015.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        An experiment was conducted to study the potential of thermal treated oak sawdust(steaming and steam explosion) as horticultural medium component in plug seedlings production of Chinese cabbage(Brassica campestris L.). This study involves the chemical, physical characterization and growth test of thermal treated oak sawdust(steaming and steam explosion) in order to evaluate their use as components of horticultural media. A commercial peat moss and oak sawdust were used as control. The total carbohydrate, C/N ratio, pH, phenolic compound, total porosity and water holding capacity were 45.1g/100g dry wt, 425.1, 4.4, 141.8mg/g wt, 82.5%, 47.1% in oak sawdust and 39.2g/100g dry wt, 300.3, 4.7, 131.7mg/g wt, 84.9% and 49.2% in steamed oak sawdust and 30.3g/100g dry wt, 247.8, 5.7, 40.8mg/g wt, 92.3% and 51.7% in steam exploded oak sawdust, respectively. The mixtures of the horticultural media were prepared using different substrate as peat moss, oak sawdust, steamed oak sawdust, steam exploded oak sawdust and perlite to grow Chinese cabbage in a greenhouse. The seed germination, stem height and leaf area were 68%, 2.2cm, 1.1cm2 in OSP(containing 90% oak sawdust and 10% perlite) and 69%, 2.5cm, 1.5cm2 in SMP(containing 90% steamed oak sawdust and 10% perlite) and 87%, 3.0cm, 2.2cm2 in SEP(containing 90% steam exploded oak sawdust and 10% perlite), respectively. The leaf area SEP(containing 90% steam exploded oak sawdust and 10% perlite) was higher than that of PP(containing 90% peat moss and 10% perlite). This research indicates that steam exploded oak sawdust may be utilized as a suitable replacement for peat moss in horticultural media component for Chinese cabbage.
        4,200원
        77.
        2014.07 구독 인증기관 무료, 개인회원 유료
        As advances in digital technologies (e.g., Apps, QR code, RFID tag) is rapidly changing market environment, marketing researches have extended technology acceptance models in different contexts. Since a supermarket chain, “Home Plus,” in Korea, had opened the first QR code virtual store at the subway platform in 2011, many firms attempt to use QR code technology convergence into their retail business. According to a survey report (Embrian, 2012), QR codes are highly familiar with consumers in Korea, and more than 70% mobile phone users have ever scanned QR codes. Due to ubiquitous nature of QR codes, it is obviously implied that marketers would capitalize the QR code technology on their retail business. Yet, it is skeptical for individuals to adopt QR code virtual store because it is in an infant stage in the retail store context. Therefore, marketers need to predict acceptance and use of QR code virtual store from a consumer perspective. Based on UTAUT (Unified Theory of Acceptance and Use of Technology) suggested by Venkatesh et al. (2003; 2012), this study formulated consumer acceptance model with four core determinants of intentions in the context of QR code virtual stores. Specific objectives are (a) identify perceived value in the context of QR code virtual store; (b) test the changes in consumer perceived value by experience over time; and (c) to predict UTAUT model for consumer acceptance to use QR code virtual store across different time points (i.e., from the time of their initial introduction to stages of experience). A longitudinal field study was conducted at the selected QR code virtual stores among individuals using smart phones. A self-administered questionnaire was developed based on literatures the context of consumer use of QR code virtual store. The multi-item scales of perceived value (i.e., performance expectancy, effort expectance, social influence, and facilitating condition) were adapted from Venkatesh et al.’s (2003) UTAUT constructs. Four items of behavioral intention to use QR code virtual store was developed. All items were measured on 5 points rating scale. Sample in this study was obtained from volunteers who participated in three different points in time: initial experience (T1), one month after first experience (T2) and three months after second experience (T3). Participants were required to visit to an assigned QR code store and do shopping task per each time. Then, they were asked to answer the questions on a survey, and there were 123 valid respondents to the first stage of the field experiment. As removed the respondents who did not participate in T2 or T3 point, a total of 309 pooled data across time (103 each time) were analyzed. The sample represents more females (n=66, 68%) than males (n=31, 32%), aging from 19 to 29 years (mean=21.58 years). Preliminarily, using the data pooled across times, factor analysis was conducted to identify underlying constructs for all research variables. As expected, a factor analysis of perceived value constructs revealed four factors: social influence (5 items), performance expectancy (5 items), effort expectancy (4 items), and facilitating condition (3 items). All factor loadings were ranged from .63 to .86, and all internal consistency reliabilities were greater than .80. Also, a unidimensional behavioral intention (4 items) confirmed to be valid (factor loadings=.88 to .93) and reliable (α=.94). Therefore, it is deemed that content validity and reliability were within acceptable ranges for further analysis. Of the four perceived value constructs, there were significant differences in the effort expectancy (F=7.10, p<.01) and facilitating condition (F=8.22, p<.001) across times of experience. Specifically, the perceive effort expectancy tended to be increased over time, indicating a difference of means between T1 and T2 at the significant level of .01 as a result of Duncan’s post-hoc test. With respect to facilitating condition, the mean tended to be increased over time, but post hoc test indicated a significant difference between T1 and T2. The perceived effort expectancy and facilitating condition tended to be changed in positive from T2 to T3 point, which were not significantly different. Therefore, the finding implies that the second stage of experience (i.e., one month after first experience) is a critical point for consumers to increase perceived value of QR code virtual store as a new retail technology. Otherwise, the other factors, such as social influence, performance expectancy and behavioral intention were not significantly increased during the three times of experience. To predict UTAUT model for consumer acceptance to use QR code virtual store, behavioral intention was served as dependent variable and the four factors of perceived value were served as independent variables in regression analysis. In the initial experience (T1), behavioral intention was significantly predicted by social influence (β=.39, t=4.42, p<.001) and performance expectancy (β=.46, t=4.44, p<.001), which explained for 57% of total variance (F=32.08, p<.001, adjusted R²=.57). In the second experience (T2), behavioral intention was significantly predicted by three factors, such as social influence (β=.43, t=5.91, p<.001), performance expectancy (β=.35, t=4.10, p<.001) and facilitating condition (β=.15, t=2.32, p<.05), accounted for 68 % of total variance (F=52.35, p<.001, adjusted R²=.68). In the three month after second experience (T3), behavioral intention was significantly predicted by social experience (β=.36, t=3.33, p<.01) and performance expectancy (β=.33, t=3.33, p<.001), accounted for 52 % of total variance (F=27.65, p<.001, adjusted R²=.52). This study supports the UTAUT model for consumer acceptance of QR code virtual store over time from a theoretical perspective. It should be noted that social influence and performance expectancy appears to be a determinant of behavioral intention to use in most situations. The effect of facilitating condition on behavioral intention was only significant when experienced in second stage. In addition, future study needs to expend technology acceptance model of virtual store in conjunction with digital technological attributes across different product categories.
        3,000원
        78.
        2014.04 구독 인증기관·개인회원 무료
        Polyhedrin is the major component of the nuclear viral occlusions produced during replication of the baculovirus Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV). To enhance the production efficiency of foreign protein in baculovirus expression system, the effects of various polyhedrin fragments were investigated by fusion expressing them with the enhanced green fluorescent protein (EGFP). Recombinant viruses were generated to express EGFP fused with polyhedrin fragments based on the previously reported minimal region for self-assembly and the KRKK nuclear localization signal (NLS). The marked increase of EGFP by these fusion expressions was confirmed through protein and fluorescence intensity analyses. Among the fusion-expressed protein in nucleus and cytoplasm, the most hyper-expression was observed in the fusion of amino acids 19 to 110 and 32 to 59 of polyhedrin. Also these fragments, some degradation of only the fused polyhedrin was observed in the fusion of amino acids 19 to 85 and 32 to 85. The production of E2 protein, which is a major antigen of classical swine fever virus, was dramatically increased by fusion expression with polyhedrin amino acids 19 to 110, and its preliminary immunogenicity was verified using experimental guinea pigs. The production of luciferase was approximately two folds increased by fusion expression with polyhedrin amino acids 32 to 59, and its activity was measured using Luminometer. This study suggests a new option for higher expression of useful foreign recombinant protein using the partial polyhedrin fusion expression in baculovirus.
        79.
        2013.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The fact that flip-flops, one of many different types of unstable shoes, are light and relatively easy to put on, accounts for their popularity among people. But because flip-flops rely heavily on the support of a single thong between your first and second toes, they impose a huge amount of pressure onto lower leg. Thus in the following experiment we tried to examine the different effects of flip-flops and running shoes in terms of their effect on muscle activity and fatigue of tibialis anterior and gastrocnemius during walking. In order to measure an electromyogram we used Free EMG system. 10 men and 10 women in running shoes ran on treadmills for 15 minutes at 4.8km/h, 2 days later the same experiment was carried out, but this time, in flip-flops. p value turned out to be greater than .05 and thus there was no considerable difference between the effects of flip-flops and running shoes on muscle activity and fatigue during walking. Therefore we conclude that despite the fact that flip-flops are considered unstable, their effects on muscle activity and fatigue of tibialis anterior and gastrocnemius are negligible.
        3,000원
        80.
        2013.04 구독 인증기관·개인회원 무료
        Mealworms, Tenebrio molitor (L.) is used as an important animal feed additive for growth promotion and health management, but potentially exposes to fungal infection. In this work, virulence of two species of entomopathogenic fungi against the insect, and the relationship between abiotic features and virulence were investigated. Secondly our consideration was also given to the effect of chemical fungicides on conidial germination for risk control. Between Beauveria bassiana (Bb) and Metarhizium roberstii (Mr) (previously M. anisopliae), Bb isolates had much higher virulence (~100% mortality in 3~4 days after the treatment), rather than Mr isolates in laboratory assays. Next, fungus-treated mealworms were kept at wheat bran at 20, 25, 30 and 35℃ with 3, 6, 9 times of water spray to the feeds for set-up of different humidity conditions. Inoculation of fungi to mealworms was conducted by fungal spray and feeding methods, which resulted in higher virulence in feeding method. In the feeding method, all temperature treatments except 35℃ showed high virulence against mealworms, but any significant relationship between virulence and humidity was not observed. In the chemical fungicide screening, fluazinam (CAS No. 79622-59-6) and mancozeb (8018-01-7) significantly inhibited the germination of Bb and Mr conidia. This work suggest that contamination of wheat bran with fungal pathogens, particularly B. bassiana may induce mycosis of mealworms, but introduction of effective fungicides possibly reduce fungal infection.
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