• 한국초지조사료학회지
• /
• 제11권1호
• /
• pp.1-5
• /
• 1991

Tall fescue(Festuca amndinacea Schreb.) is a productive pasture grass that is widely adapted to the soil and climate of Korea. It is regarded, however, as relatively low in palatability and nutritive value. On the other hand, Italian ryegrass(lo1ium rnultz$om Lam.) is highly nutritious and palatable, but is essentially weak in cold tolerance. Numerous investigators have succeeded in producing hybrids between Lolium spp. and Festuca spp. but no improved varieties have resulted. Therefore, intergeneric hybridization of Italian ryegrass with tall fescue is employed in 1984 to improve the adaptive and cold resistance quality of Italian ryegrass. In the mean time, F1-hybrid plants obtained by crossing Italian ryegrass x tall fescue were observed in open field. The results are summarized as follows: 1. Leaf-size and silica cell hair were intermediate between the types of parents but the shape of auricle tended to show Italian ryegrass and auricle-cilia to show tall fescue. 2. Roots of $F_1$-hybrid plants were mainly distributed at top soil and did not produced florescence material. 3. Head type of hybrids was intermediate between the types of parents but ray length was somewhat less than the length of tall fescue ray. Typical Italian ryegrass or tall fescue-like phenotypes were not observed. 4. Anthers of $F_1$-hybrid plants were formed but pollen were not formed. Even though pollen were formed, they were all empty. 5. Hybrid plants were more winterhardy and summer persistency than Italian ryegrass. They showed a equivalent growth to Italian ryegrass in spring and to tall fescue in summer. 6. Chromosome of $F_1$-hybrids was allopolyploid(2n=4~=28) and all $F_1$-hybrid plants were sterile.

• 한국지구과학회지
• /
• 제22권4호
• /
• pp.317-326
• /
• 2001

한국 서남해안에 위치한 반폐쇄형 함평만 해안선은 대부분 높이 3m 미만의 급한 경사면을 가진 해안절벽으로 이루어져 있다. 해안절벽은 주로 연약한 풍화암 또는 적색 토양층으로 구성되어 있어 매우 불안정하며, 활발한 침식활동이 진행되고 있다. 1976년과 1990년에 촬영된 항공사진을 이용한 단사진 측정법(photogrammetry)을 통하여 이들 해안절벽 침식에 따른 해안선 변화(후퇴)를 정량적으로 계산한 결과, 함평만 해운리 해안선의 침식율(후퇴율)은 매년 1${\sim}$2m 정도로 계산되었으며, 이는 장 외(1999)에 의하여 현장에서 직접 관측${\cdot}$측정된 침식율과 일치하는 것으로 나타났다. 따라서 보 연구에서 적용한 단사진 측정법은 앞으로 해안선의 장기적 변화를 정량화하고 해석하는데 매우 유용한 방법으로 평가된다. 또한, 함평만에서의 활발한 해안침식은 간헐적으로 발생되는 고에너지의 태풍 및 폭풍에 의한 이상고조와 매우 불안정한 토양으로 구성된 해안절벽의 지질 특성 등의 복합적인 상호작용에 의한 것으로 해석된다.

• The Plant Pathology Journal
• /
• 제30권3호
• /
• pp.261-268
• /
• 2014

This work was conducted to identify mungbean genotypes showing yield stability and resistance to mungbean yellow mosaic virus (MYMV) disease. Sixteen genotypes were evaluated in a randomized complete block design with two replications for two years (2011 and 2012) at three locations (Gazipur, Ishurdi and Madaripur) of the Bangladesh Agricultural Research Institute. An analysis of variance exhibited significant effects of genotype (G), environment (E), and genotype ${\times}$ environment ($G{\times}E$) on grain yield. Among eight agronomic characters, the principal component 1 (PC1) was always higher than the PC2. Considering $G{\times}E$ interaction, BM6 was the best genotype at all three locations in both years. Based on grain yield and stability performance, BM6 ranked first while the worst performing genotypes were BM1 and G10. Based on discrimination and representation, Gazipur was identified as an ideal environment for these mungbeans. Relationship between soil-plant analysis developments (SPAD) value was positive with yield but negative with MYMV severity. BM6, G1 and G2 were considered as promising sources of resistance for low disease score and stable response across the environments. The environment proved to have an influence on MYMV infection under natural infestation. A positive correlation was observed between disease score and the temperature under natural growing condition.

• 한국지반공학회논문집
• /
• 제25권8호
• /
• pp.57-64
• /
• 2009

본 연구에서는 등가변형을 이용하며 테이퍼 말뚝의 지지력을 산정하는 방법을 제안하였다. 지반조건과 테이퍼각도를 고려하여 지지력을 산정하던 기존의 방법과 달리, 테이퍼말뚝의 지지력산정시 콘관입시험 결과를 활용하도록 하였다. 이때 테이퍼말뚝은 등가변형을 이용하여 형태를 단순화 시켰으며 이를 통해 실무에서 비교적 쉽게 지지력을 산정 할 수 있는 방법을 제안하였다. 제안된 방법의 검증을 위해 실내시험과 현장시험을 실시하였다. 실내모형시험 결과로부터 측정된 극한지지력과 본 연구에서 제안된 방법에 의한 예측값을 비교한 결과 표준편차는 $0.05{\sim}0.121$, COV는 $0.04{\sim}0.05$의 값을 보여 대체적으로 유사한 결과를 보였으며, 현장시험은 약 2.5%의 오차를 보여 측정값에 근접함을 알 수 있었다. 그 결과 제안된 지지력 산정법은 테이퍼말뚝의 지지력을 비교적 정확하게 예측하는 것으로 나타났다.

• 방사선산업학회지
• /
• 제17권2호
• /
• pp.183-190
• /
• 2023

The global problem of handling radioactive materials is facing limitations. Eco-friendly bioremediation methods using microorganisms are being studied. This study was conducted to screen cesium-resistant microbial strains. M1 strain was selected from the soil sample by enriched culture in R2A medium containing 100 mM CsCl. In liquid medium containing above 40 mM of CsCl, the growth of M1 was inhibited in a concentration-dependent manner. Otherwise, M1 can survive up to 80mM CsCl in solid medium although the growth rate was slow and colony size was small. M1 strain was genetically identified as a strain of the genus Acinetobacter through 16S rRNA sequencing, and radiation resistance (D10 value) of M1 was found to be 0.307 kGy. These results showed that M1 strain is highly resistant to cesium and can grow in radiation environment. It was considered that M1 strain is useful in the field of biological decontamination of cesium.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2003년도 봄 학술발표회 논문집
• /
• pp.315-322
• /
• 2003

Cyclic simple shear tests were performed to find out the effect of preshear on dynamic strength of the sandy soil. Tests were performed for the specimens with 40% and 60% of relative density, under three different effective vertical stress of 50, 100 and 200kPa. For 50 and 100kPa, preshear ratios 0.00, 0.08, 0.12 and 0.16 were given, respectively, For low and high relative densities, two different results are shown in dynamic tests. Under the dense conditions, the maximum shear stress ratio($\tau$$\_$cyc//$\sigma$$\_$vo/) and the cyclic shear stress ratio($\tau$$\_$cyc//$\sigma$$\_$vo/) causing a certain shear strain increase with augmenting preshear ratio(${\alpha}$). However, the maximum shear stress ratio and the cyclic shear stress ratio increase or decrease with increasing preshear ratio under the loose conditions. Correction factor(K$\_$${\alpha}$/) for preshear increases at an early stage and then decreases with increasing preshear ratio at loose condition and increase with increasing preshear ratio at dense condition. Correction factor (K$\_$${\alpha}$,Max/) for preshear increases with the increasing preshear ratio irrespective of relative density, and the value of has same behavior as K$\_$${\alpha}$/.

• Journal of Microbiology and Biotechnology
• /
• 제8권2호
• /
• pp.111-118
• /
• 1998

A bacterium producing unique antistaphylococcal substance (ASS) was isolated from soil samples. The isolated strain KUH-001 was identified to belong to Pseudomonas species from the characteristic properties of its fluorescence and cellular 3-hydroxy fatty acid composition, etc. The ASS component was purified by procedures employing activated carbon adsorption, column chromatography with silica gel, preparative TLC and HPLC. This compound could also be purified mainly by repeating of trituration and precipitation with chilled ether. Purified ASS with a m.p. value of $140~142^{\circ}C$ showed marked stability at high temperature (at $121^{\circ}C$ for 10 min) and extreme pHs (in 1N HC1 and 1N NaOH for 1 day) without significant loss of antibiotic activity. From spectral data of UV, IR, NMR, and FAB-MS, the compound was elucidated as 2-heptyl-4-hydroxyquinoline N-oxide (HHQO). Under the conditions employed, HHQO exhibited a narrow antimicrobial spectrum. active particularly against Staphylococcus aureus including the methicillin resistant strain. Moreover, it did not induce resistance, and besides, interacted synergistically with certain antibiotics such as vancomycin or erythromycin.

• Journal of Information Processing Systems
• /
• 제14권5호
• /
• pp.1136-1149
• /
• 2018

With the increasing of urban electricity demand, making the most use of the power cable carrying capacity has become an important task in power grid system. Contrary to the rated ampacity obtained under extremely conservative conditions, this paper presents the various steady value of cable ampacity by using the changing surrounding parameters under operation, which is based on cable ampacity calculation equation under the IEC-60287 standard. To some degree, the cable ampacity analysis of actual surroundings improves the transmission capacity of cables. This paper reveals the factors that influence cable ampacity such as insulating layer thickness, allowable long-term conductor temperature, the ambient temperature, soil thermal resistance coefficient, and so on, then gives the class of the influence of these parameters on the ampacity, which plays a great role in accurately calculating the real-time ampacity and improving the utilization rate of cable in the complex external environment condition. Furthermore, the transient thermal rating of the cable is analyzed in this paper, and temperature variation of the conductor under different overload conditions is discussed, which provides effective information for the operation and control of the system.

• Geomechanics and Engineering
• /
• 제2권3호
• /
• pp.177-190
• /
• 2010

This paper presents the details of indigenous development of the piezovibrocone and calibration chamber. The developed cone has a cylindrical friction sleeve of $150cm^2$ surface area, capped with a $60^{\circ}$ apex angle conical tip of $15cm^2$ cross sectional area. It has a hydraulic shaker, coupled to the cone penetrometer with a linear displacement unit. The hydraulic shaker can produce cyclic load in different types of wave forms (sine, Hover sine, triangular, rectangular and external wave) at a range of frequency 1-10 Hz with maximum amplitude of 10 cm. The piezovibrocone can be driven at the standard rate of 2 cm/sec using a loading unit of 10 ton capacity. The calibration chamber is of size $2m{\times}2m{\times}2m$. The sides of the chamber and the top as well as the bottom portions are rigid. It has a provision to apply confining pressure (to a maximum value of $4kg/cm^2$) through the flexible rubber membrane inlined with the side walls of the calibration chamber. The preliminary static as well as dynamic cone penetration tests have been done sand in the calibration chamber. From the experimental results, an attempt has been made to classify the soil based on friction ratio ($f_R$) and the cone tip resistance ($q_c$).

• Geomechanics and Engineering
• /
• 제10권5호
• /
• pp.617-633
• /
• 2016

A numerical study has been conducted to examine the improvement achieved in the ultimate pullout capacity of horizontal circular anchor plates embedded in undrained clay, by constructing granular columns of varying diameter over the anchor plates. The analysis has been carried out by using lower bound theorem of limit analysis and finite elements in combination with linear programming. The improvement in uplifting capacity of anchor plate is expressed in terms of an efficiency factor (${\xi}$). The efficiency factor (${\xi}$) has been defined as the ratio of ultimate vertical pullout capacity of anchor plate having diameter D embedded in soft clay reinforced by granular column to the vertical pullout capacity of the anchor plate with same diameter D embedded in soft clay only. The variation of efficiency factor (${\xi}$) for different embedment ratios and different diameter of granular column has been studied considering a wide range of softness of clay and different value of soil internal friction angle (${\phi}$) of the granular material. It is observed that ${\xi}$ increases with an increase in diameter of the granular column ($D_t$) and increase in friction angle of granular material. Also, the effectiveness of the usage of granular column increases with decrease in cohesion of the clay.