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        검색결과 8

        1.
        2020.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present study investigated effects of antifungal and carboxylesterase inoculant on rumen fermentation with different rumen pH. Corn silage was treated without inoculant (CON) and with a mixed Lactobacillus brevis 5M2 and L. buchneri 6M1 (MIX). Rumen fluid was collected from two cannulated Hanwoo heifers before morning feeding (high rumen pH at 6.70) and 3 h after feeding (low rumen pH at 6.20). Dried corn silage was incubated in the rumen buffer (rumen fluid + anaerobic culture medium at 1:2 ratio) for 48 h at 39oC. Eight replications for each treatment were used along with two blanks. Both in a high and a low rumen pH, MIX silages presented higher (p<0.05) the immediately degradable fraction, the potentially degradable fraction, total degradable fraction, and total volatile fatty acid (VFA) than those of CON silages. Incubated corn silages in a low rumen pH presented lower (p<0.05) total degradable fraction, ammonia-N, total VFA (p=0.061), and other VFA profiles except acetate and propionate, than those in a high rumen pH. The present study concluded that application of antifungal and carboxylesterase inoculant on corn silage could improve degradation kinetics and fermentation indices in the rumen with high and low pH conditions.
        4,000원
        2.
        2018.05 구독 인증기관·개인회원 무료
        The Semi-Rigid Pavement (SRP) mixture is composed of Gap Graded Asphalt (GGA) mixture (air void = 20~28%) and cement paste. By inserting cement paste into voids in GGA mixture, SRP can provide not only flexibility but also rigidity characteristics on pavement performance. SRP can mitigate pavement surface temperature increase during summer session, provide better smoothness and mitigate rutting distress due to heavy weight vehicles, successfully. In Japan, SRP is widely applied in cross section area, heavy vehicle parking lot and highway ticketing booth in highway network system. In South Korea, SRP was introduced and applied since 2005. However, still more researches and studies are needed to understand material characteristics and improve performance of SRP. Moreover, the current SRP system in South Korea merely follows and adapts the aggregate gradation information from Japan which needs to be amended and customized into original material (i.e. aggregate, binder and cement) situation of South Korea. In this paper, SRP system based on Stone Mastic Asphalt (SMA) mixture design originated from Korea Expressway Corporation (KEC) and enhanced cement paste with addition of fly-ash and slags was developed. In addition, an optimized proportion between asphalt mixture air voids and cement paste amount with consideration of economic benefit was introduced. Based on field evaluation process it can be said that the newly developed SRP system can successfully adapted not only in static site on highway: parking lots or ticketing booth, but also in dynamic site on highway: driving and wheel path.
        3.
        2018.05 구독 인증기관·개인회원 무료
        In case of performing asphalt pavement overlay on existing concrete pavement layer, applying asphalt emulsion tack-coating or spreading prime-coating is considered to improve adhesion between asphalt and concrete layer. After coating work is done a curing process is considered not only for promoting evaporation process in coated (and/or spread) asphalt emulsion, but also for generating a membrane which can act as a bonding agent. Finally, asphalt overlay construction is performed when this curing process is completely done. However, during asphalt overlay construction process remarkable amount of spread tack-coating layer is lost due to asphalt material transfer vehicles (e.g. trucks, approximately 40~50% of total spread tack coating material is lost). In this paper, a new pavement equipment contains simultaneous asphalt emulsion spreading ability and corresponding construction techniques are introduced. Through applying this equipment, non-stop two step sequent working process: spreading asphalt emulsion on to existing concrete pavement layer then paving asphalt material for overlay construction, is available. During pavement working process temperature of asphalt material was kept with ranged between 130ºC and 170ºC. After performing field performance evaluation, it was found that crucial improvement in pavement layer adhesion, crack and rutting resistant ability were observed compared to the conventional paving method.
        4.
        2011.10 구독 인증기관·개인회원 무료
        Recently, the Q biotype of tobacco whitefly has been recognized as the most hazardous strain of worldwide because of increased resistance to some insecticide groups requiring alternative strategies for its control. We studied the susceptibility of this biotype of B. tabaci to 21 isolates of Beauveria bassiana, 3 isolates of Isaria spp., 1 isolate of P. cateni,3 isolates of Lecanicillium lecanii, 1 isolate of L. attenuatum and 1 isolate of Aschersonia aleyrodes. These isolates were evaluated on pruned egg plant seedlings, at a concentration of 108conidia/ml (deposited at 6000±586 conidia mm-2). The mortality based on mycosis varied from 18 to 97% after 6 days. An Isaria sp. isolate, two B. bassiana isolates and a L. lecanii isolate were found the most effective. Furthermore, five isolates were chosen for concentration-mortality response assays and compared to B. bassiana GHA as a standard. The numbers of nymphs infected by fungi were correlated with the spore concentration. A L. lecanii isolate and Isaria sp. had the short LT50 at 6000±586 conidia mm-2. Mortality reduced and LT50s were longer as the concentration of conidia was reduced. The LD50 values were differed in isolates from 87 to 269 conidia mm-2. These results indicated that the Q biotype of sweetpotato whitefly was susceptible to the five isolates of entomopathogenic fungi and these isolates have potential to be developed as a microbial pesticide for whitefly control.
        5.
        2002.10 구독 인증기관 무료, 개인회원 유료
        We give efficient algorithms for finding shortest distances in special types of sparse network where the networks are composed of series of subnetworks which form circles. The algorithms presented in this paper are so called extensions of the non-circular sparse network algorithms The suggested algorithm is composed of two approach parts for only donut shaped sparse network, the one is the node elimination approach and the other the arc elimination approach, Our algorithms for finding all shortest distances can be extended in general circular sparse networks.
        4,000원
        7.
        2016.05 서비스 종료(열람 제한)
        Background : For increasing saponin content of ginseng cultivated in shaded plastic house, this study was performed to investigate growth characteristics and saponin content of ginseng (Panax ginseng C.A. Mayer) according to foliar spray of germanium and water-soluble silicates processing. Methods and Results : Used a native species in this study is violet-stem variant that most commonly cultivated in ginseng’s farms. 1-year-old violet-stem variant was transplanted on March 24, 2015 and planting distance was 11 × 20 cm. Shading material of plastic house was used blue-white shading vinyl. The processing method of inorganic dissolved matter is as follows, we were diluted with germanium and water-soluble silicates to 500-fold, 1000-fold and investigated after foliar spray twice a month from May to September. The growth characteristics in above-ground part of 2-year-old ginseng was a good in the inorganic matters treatment compared to the control treatment, the difference of above-ground growth characteristics between the inorganic dissolved matters treatments was not significant. The growth characteristics in under-ground part of 2-year-old ginseng was a good in the inorganic matter treatments and root weight per plant in the 500-fold dilution of germanium was 12.4 g that increased by 29 % compared to the control (9.6 g). Crude saponin content of under-ground part was higher generally in inorganic matter treatments compared to the control (11.53 ㎎/g). In the 1000-fold dilution of water-soluble silicate and germanium (50:50), crude saponin content was the highest in 12.91 ㎎/g. Crude saponin content of above-ground part was higher generally in inorganic matter treatments compared to the control (61.76 ㎎/g). In the 1000-fold dilution of water-soluble silicate and germanium (50:50), crude saponin content was the highest in 65.69 ㎎/g. Conclusion : From the above results, we concluded that germanium and water-soluble silicates could be useful matters in promoting growth characteristics and saponin content of ginseng (Panax ginseng C.A. Mayer).
        8.
        2016.05 서비스 종료(열람 제한)
        Background : This study was performed to set proper soil moisture tension for promoting seed emergence and yield of ginseng when direct seeding cultivation of ginseng was carried out in shaded plastic house. Methods and Results : The test cultivars were used Cheonpung, Yeonpung, Geumpung and seeds were sown on November 20, 2013. Irrigation starting point was set to 30, 40, 50 kPa and irrigation breakpoint was set to 20 kPa. Ginseng was cultivated in clay loam soil and shading material of plastic house were used blue-white shading vinyl. The emergence rate of 3-year-old ginseng cultivars in accordance with soil moisture tension indicated Cheonpung 97.0%, Yeonpung 95.0%, Geumpung 95.3% in each 50 kPa, 50 kPa, 30 kPa. In general, emergence rate of ginseng was higher tendency in 50 kPa (93.3∼97.0%). The average absolute soil moisture content during the growing season indicated a moisture content of 19.3% (30 kPa), 17.9% (40 kPa), 16.2% (50 kPa). Looking at the growth characteristics in above-ground part of 3-year-old ginseng cultivars according to soil moisture tension, Yeonpung, Cheonpung and Geumpung were good growth tendency in each 30kPa, 40kPa, 50kPa. On the other hand, looking at the growth characteristics in underground part of 3-year-old ginseng cultivars according to soil moisture tension, Cheonpung, Geumpung and Yeonpung were good growth tendency in each 30kPa, 40kPa, 50kPa. Yield per 10a was indicated that Yeonpung was the highest in the 50kPa to 456kg. Yield per 10a of Cheonpung and Geumpung indicated 347kg, 263kg in each 30kPa, 50kPa. Conclusion : From the above results, we concluded that ginseng(Panax ginseng C.A. Mayer) seems to be a difference of growth characteristics according to soil moisture tension. Therefore, it is need to manage soil moisture for each ginseng cultivars