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        검색결과 10

        1.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The aim of this study is to review freeze-and-thaw testing apparatuses, develop a freeze-and-thaw testing setup with a test protocol, test the freeze-and-thaw properties of soils collected from different parts of South Korea, and suggest an index for frost susceptibility criteria for soils found in South Korea. METHODS : Based on a literature review, a new freeze-thaw testing setup was developed. In addition, a test protocol was developed for freeze-thaw testing. Soils collected from different parts of South Korea and bedding sand used for block pavements were tested to determine whether the measurements from the newly developed test setup could capture important freeze-thaw characteristics of the soils. Finally, to develop local frost susceptibility criteria, a parameter including both the vertical deformation and thermal conductivity characteristics of the soils was suggested. RESULTS : The results from the laboratory experiments indicate that the newly developed freeze-and-thaw setup captures the required parameters to quantify the responses of soils subjected to cyclic freeze-and-thaw testing. In addition, a vertical deformation of up to 2.437 mm is measured. Moreover, seven soils out of the nine tested soils are classified as having a medium frost susceptibility, whereas the remaining two show low frost susceptibility. The bedding sand experiment also shows that there is a possibility of having a frost susceptible condition based on the moisture content. When submerged, the bedding sand is classified as having a medium frost susceptibility. CONCLUSIONS : The "HEART" freeze-thaw testing setup was able to capture the parameters required for evaluating the frost susceptibility of soils. This setup and testing procedure could be further used to test and prepare criteria for classifying the frost susceptibility of soils found in South Korea.
        4,000원
        2.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 반밀폐형 토마토 재배 온실에서 광합성율 극대화를 위한 적정 탄산가스 시비 농도를 구명하고자 광합성 모델을 이용하여 잎의 최대 카복실화율(Vcmax), 최대 전자전달속도(Jmax), 열파괴, 잎 호흡 등을 계산하고 실제 측정값과 비교하였다. 다양한 광도(PAR 200μmol·m -2 ·s -1 to 1500μmol·m -2 ·s -1 )와 온도(20°C to 35°C) 조건에서 CO2 농도에 대한 A-Ci curve는 광합성 측정 기기를 사용하여 측정하였고, 모델링 방정식으로 아레니우스 함수값 (Arrhenius function), 순광합성율(net CO2 assimilation, An), 열파괴(thermal breakdown), Rd(주간의 잎호흡)를 계산 하였다. 엽온이 30°C 이상으로 상승하였을 때 Jmax, An 및 thermal breakdown 예측치가 모두 감소하였고, 예측 Jmax의 가장 최고점은 엽온 30°C였으며 그 이상의 온도에서는 감소하였다. 생장점 아래 5번째 잎의 광합성율은 PAR 200- 400μmol·m -2 ·s -1 수준에서는 CO2 600ppm, PAR 600-800μmol·m -2 ·s -1 수준에서는 CO2 800ppm, PAR 1000μmol·m -2 ·s -1 수 준에서는 CO2 1000ppm, PAR 1200-1500μmol·m -2 ·s -1 수준에서는 CO2 1500ppm을 공급했을 때 포화점에 도달하였다. 앞으로 광합성 모델식을 활용하여 과채류 온실 재배 시 광합성을 높일 수 있는 탄산시비 농도를 추정할 수 있을 것으로 판단된다.
        4,000원
        3.
        2016.10 구독 인증기관·개인회원 무료
        An Oriental genus Paraleprodera Breuning, 1935 (Coleoptera: Cerambycidae: Lamiinae: Monochamiini) has been found for the first time in Korea in the form of Paraleprodera diophthalma diophthalma (Pascoe, 1857) from South Korea. We provide the first description of the genital structure and immature stage of Paraleprodera. A diagnosis of the genus, re-description, biological information and illustrations of P. diophthalma diophthalma are also provided.
        4.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        한반도 하늘소과의 미기록 Parechthistatus속을 처음 확인하고, Parechthistatus gibber (Bates)의 한반도 분포를 보고한다. 성충 및 유충의 사진 및 서식처 등 형태학적 정보와 생태학적 정보를 함께 제공한다.
        3,000원
        5.
        2013.12 구독 인증기관 무료, 개인회원 유료
        We studied antioxidant activity and inhibitory effect of α-glucosidase from aqueous, ethanolic and methanolic fractions of Galla rhois. In FRAP and ORAC assay for measuring antioxidant activity, we confirmed that Galla rhois extracts had strong antioxidant activity and ethanolic and methanolic extracts were relatively stronger than aqueous extract. We used trolox as a positive control. In order to measure the inhibitory effect of α-glucosidase, we compared acarbose and Galla rhois extracts. As a result of α-glucosidase inhibitory assay, aqueous, ethanolic and methanolic extracts of Galla rhois showed high inhibitory activitity and ethanolic and methanolic extracts were relatively stronger than aqueous extract. The 50% inhibitory concentrations (IC50s) of acarbose, aqueous, ethanolic and methanolic fractions were 0.45 mM, 0.53 μg/mL, 0.415 μg/mL and 0.37 μg/mL, respectively. These results suggest that Galla rhois extracts can be a clinically useful anti-diabetic ingredient, indicating that it needs to be fractionated and isolated and should be further investigated.
        4,000원
        6.
        2011.05 구독 인증기관·개인회원 무료
        The bulb mite (Rhizoglyphus echinopus) is damage garlic, shallot, onion in the bulbs, corms, tubers. It has recently become a serious problem because of the continuous use of acaricides resulting in resistance among bulb mite population. Thus, there is need to find alternative control measures to suppress bulb mite population. Initial screenings were performed using 352 isolates of pathogenic fungi from Korea soils. As results, 9 strains of acaropathogenic fungi were cadavers of bulb mite supporting fungal conidiation. These isolated were identified as 8 strains of Metarhizium anisopliae (4-1, 4-3-1, 4-3-2, 4-8-1, 4-4-1, 4-14-2, 4-16-1,and 4-31-2), 2 strains of Beauveria bassiana (4-4-2) by microscopic examination and genetic sequencing of the ITS region. However, ITS sequence analysis was consistent with the Metarhizium anisopliae (4-1, 4-3-1, 4-4-1, 4-31-2; a, 4-8-1, 4-14-2, 4-16-1; b, 4-3-2; c). Therefore, genetic diversity of selected in vitro isolates was characterized by Universally Primed (UP) PCR. The divided with Metarhizium anisopliae 4strain by UP-PCR. Of the 5stain isolation tested, 5stain resulted in mortality rates ≥20% within 6 days and all fungal treatment was detected mycosis. Thus these species of acaropathogenic fungi can be considered promising for biological control of bulb mite.
        7.
        2019.08 KCI 등재 서비스 종료(열람 제한)
        The pathological condition of excessive melanogenesis causing freckles, melasma, senile lentigo, pigmented acne scars, and cancer has a critical impact on the wellness of individuals. The mechanism of melanogenesis is related to the expression of melanogenic enzymes. Here, we evaluated the inhibitory effect of pine cone (Pinus densiflora) extracts on melanogenesis. P. densiflora, the Korean Red Pine, is the predominant tree species in the cool, temperate forests of northeast Asia, occurring in pure stands across Korea, Japan, and parts of northern China and Russia. P. densiflora leaves, pollen, and bark have been widely used for traditional medicine, or edible purposes. However, pine cones are rarely used as natural raw materials, although they contain many bioactive phytochemicals. The pine cone ethyl acetate fraction (PEF) showed no toxicity to B16F10 cells at a concentration of less than 100 ㎍/mL. PEF inhibited the expression of microphthalmiaassociated transcription factor (MITF), tyrosinase and tyrosinase-related factors in B16F10 cells treated with 3-Isobutyl- 1-methylxanthine (IBMX). These results suggest that pine cones can be used as an effective natural melanogenesis inhibitory agent.
        8.
        2017.04 KCI 등재 서비스 종료(열람 제한)
        A nearshore current or a wave-induced current is an important phenomenon in a nearshore zone, which is composed of longshore, cross-shore, and rip currents. The nearshore current is closely related to the occurrence of coastal accidents by beachgoers. A considerable number of coastal accidents by beachgoers involving the rip current have been reported at Jungmun Beach. However, in studies and observations of the nearshore current of Jungmun Beach, understanding of the rip current pattern remains unclear. In this study, a scientific approach is taken to understand the nearshore current and the rip current patterns at Jungmun Beach by numerical computation for year of 2015. From results of numerical computation, the occurrence and spatial characteristics of the rip current, and the similarities between the rip current and incident wave conditions are analyzed. The primary results of this study reveal that the rip currents are frequently generated at Jungmun Beach, especially in the western parts of the beach, and that the rip currents often occur with a wave breaking height of around 0.5 ~ 0.7 m, a wave period of around 6 ~ 8 seconds, and a breaking angle of around 0 ~ 15 degrees.
        9.
        2015.07 서비스 종료(열람 제한)
        Lesion mimic mutants commonly display spontaneous cell death in pre-senescent green leaves under normal conditions, without pathogen attack. Despite molecular and phenotypic characterization of several lesion mimic mutants, the mechanisms of the spontaneous formation of cell death lesions remain largely unknown. Here, we examined the rice lesion mimic mutant spotted leaf3 (spl3). In mutants grown under a light/dark cycle, spl3 mutants appeared similar to wild type at early developmental stages, but lesions gradually appeared in the mature leaves close to heading stage. By contrast, in mutants grown under continuous light, severe cell death lesions formed in developing leaves, even at the seedling stage. Histochemical analysis showed that hydrogen peroxide accumulated in the mutants, likely causing the cell death phenotype. By map-based cloning and complementation, we showed that a 1-bp deletion in the first exon of Oryza sativa Mitogen-Activated Protein Kinase Kinase Kinase1 (OsMAPKKK1)/OsEDR1/ OsACDR1 causes the spl3 mutant phenotype. We found that the spl3 mutants were insensitive to abscisic acid (ABA), showing normal root growth in ABA-containing media and delayed leaf yellowing during dark-induced and natural senescence. Expression of ABA signaling-associated genes was also less responsive to ABA treatment in the mutants. Furthermore, the spl3 mutants had lower transcript levels and activities of catalases, which scavenge hydrogen peroxide, probably due to impairment of ABA-responsive signaling. Finally we discuss a possible molecular mechanism of lesion formation in the mature leaves of spl3 mutants.