• Journal of the Korean Geotechnical Society
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• v.32 no.12
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• pp.15-22
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• 2016

The magnitude of the lateral resistance that resists the lateral movement of the pile is controlled by the amount of the pile movement and the strength and stiffness of soil. In this paper, we proposed an equation which produces the ultimate lateral resistance of the laterally loaded single pile in sand using the strain wedge model of the soil deformation. The ultimate lateral resistance in strain wedge model is composed of earth pressure of wedge rear, the shear resistance on the side of the wedge, and the frictional resistance between pile and ground. The ultimate lateral resistance determined by the proposed equation was compared with the Ashour, F.D.M., field test in sand. As a result, the error of the proposed equation and Ashour theory, field test, F.D.M were respectively 1.03%, 0.40~3.32%, 6.02%.

• Journal of the Korean Geotechnical Society
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• v.16 no.1
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• pp.99-106
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• 2000

The main advantage of incremental loading consolidation test is the simplicity of equipments that can be used. However, it is known that the incremental loading test has several deficiencies including long testing time, non-uniform stress state, high and variable rates of strain, very soft clay and problem of back pressure saturation. Due to these drawbacks, various testing methods including constant rate of strain consolidation test(CRS) were developed. In this paper, CRS consolidation test was performed with three different strain rate. The results were verified by the modified CRS theory of Wissa et al.(1971). And then the results obtained from the CRS consolidation tests were compared with those from incremental loading test and direct permeability test.

• YAKHAK HOEJI
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• v.40 no.6
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• pp.713-719
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• 1996

Identification of soil microorganism strain B-6. a producer of acyl CoA synthetase inhibitor, based on its morphological, physiological, biochemical and chemotaxonomical charact eristics was performed. The strain B-6 was identified as Bacillus subtilis. Ihe acyl CoA synthetase inhibitor produced by this strain was highly achieved in fermentation medium that contained glucose 1.0%, soluble starch 1.0%, NH$_4$Cl 0.3%, oatmeal 1.0%, pharmamedia 1.0%, basic magnesium carbonate 0.5%. pH 7.5 at 30$^{\circ}$C for 7 days. The optimal pH and temperature for growth were 9.0 and 30$^{\circ}$C, respectively. Butanol extract of culture filterate of strain B-6 in acyl CoA synthetase inhibitor production medium containing corn steep liquor exhibited high acyl CoA synthetase inhibitor activity and antimicrobial activity against C. albicans. But chloroform extract of culture filterate of strain B-6 in medium containing NH$_4$Cl, ($NH_4)_2SO_4$ or urea instead of corn steep liquor exhibited higher antimicrobial activity against C. albicans than that of butanol extract.

• Geomechanics and Engineering
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• v.30 no.2
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• pp.201-210
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• 2022

This paper presents a study regarding the influence of various water levels on the characteristics of subgrade mud pumping through a self-developed test instrument. The characteristics of mud pumping are primarily reflected by axial strain, excess pore water pressure, and fine particle migration. The results show that the axial strain increases nonlinearly with an increase in cycles number; however, the increasing rate gradually decreases, thus, an empirical model for calculating the axial strain of the samples is presented. The excess pore water pressure increases rapidly first and then decreases slowly with an increase in cycles number. Furthermore, the dynamic stress within the soil first rapidly decreases and then eventually slows. The results indicate that the axial strain, excess pore water pressure, and the height and weight of the migrated fine particles decrease significantly with a low water level. In this study, when the water level is 50 mm lower than the subgrade soil surface, the issue of subgrade mud pumping no longer exist.

• Journal of Microbiology and Biotechnology
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• v.18 no.6
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• pp.1011-1015
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• 2008

A Gram-negative, strictly aerobic, motile bacterial strain, designated Gsoil $124^T$, was isolated from a soil sample taken from a ginseng field in Pocheon Province (South Korea). The isolate contained Q-10 as the predominant lipoquinone, plus $C_{18:1}\;{\omega}7c$ and summed feature 4 ($C_{16:1}\;{\omega}6c$ and/or iso-$C_{15:0}$ 2-OH) as the major fatty acids. The G+C content of the genomic DNA was 68.1 mol%, and the major polar lipids consisted of sphingoglycolipid, phosphatidylglycerol, phosphatidylcholine, and phosphatidylethanolamine. A comparative 16S rRNA gene sequence analysis showed that strain Gsoil $124^T$ was most closely related to Sphingopyxis chilensis (98.7%), Sphingopyxis alaskensis (98.2%), Sphingopyxis witflariensis (98.2%), Sphingopyxis taejonensis (98.0%), and Sphingopyxis macrogoltabida (97.6%). However, the DNA-DNA relatedness between strain Gsoil $124^T$ and its phylogenetically closest neighbors was less than 22%. Thus, on the basis of its phenotypic properties and phylogenetic distinctiveness, strain Gsoil $124^T$ should be classified as representing a novel species in the genus Sphingopyxis, for which the name Sphingopyxis panaciterrae sp. nov. is proposed. The type strain is Gsoil $124^T$ (=KCTC $12580^T$=LMG $24003^T$).

• Journal of Microbiology and Biotechnology
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• v.20 no.1
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• pp.15-20
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• 2010

A Gram negative, aerobic, nonspore-forming, straight or curved rod-shaped bacterium, designated Gsoil $317^T$, was isolated from soil of a ginseng field in Pocheon Province (South Korea) and was characterized using a polyphasic approach. Cells were dimorphic, with stalk (or prostheca) and nonmotile or nonstalked and motile, by means of a single polar flagellum. Comparative analysis of 16S rRNA gene sequences revealed that strain Gsoil $317^T$ was most closely related to Caulobacter mirabilis LMG $24261^T$ (97.2%), Caulobacter fusiformis ATCC $15257^T$ (97.1 %), Caulobacter segnis LMG $17158^T$ (97.0%), Caulobacter vibrioides DSM $9893^T$ (96.8%), and Caulobacter henricii ATCC $15253^T$ (96.7%). The sequence similarities to any other recognized species within Alphaproteobacteria were less than 96.0%. The detection of Q-10 as the major respiratory quinone and a fatty acid profile with summed feature 7 ($C_{18:1}\;{\omega}7c$ and/or $C_{18:1}\;{\omega}9t$ and/or $C_{18:1}\;{\omega}12t;$ 56.6%) and $C_{16:0}$ (15.9%) as the major fatty acids supported the affiliation of strain Gsoil $317^T$ to the genus Caulobacter. The G+C content of the genomic DNA was 65.5 mol%. DNA-DNA hybridization experiments showed that the DNA-DNA relatedness values between strain Gsoil $317^T$ and its closest phylogenetic neighbors were below 11%. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain Gsoil $317^T$ should be classified as representing a novel species in the genus Caulobacter, for which the name Caulobacter ginsengisoli sp. novo is proposed. The type strain is Gsoil $317^T$ (=KCTC $12788^T=DSM\;18695^T$).

• The Korean Journal of Mycology
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• v.12 no.3
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• pp.85-92
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• 1984

To isolate antibiotic-producing microorganisms from Korean soils, microbes were isolated from the soil samples and screened for antibacterial activity. A strain which was isolated from the soil sample collected in Choong Chung Book Do had a high antibacterial activity against gram-positive bacteria. The examination of morphological and physiological characteristics of that strain according to the International Streptomyces Project methods showed that it was one of Streptomyces species. After the antibacterial constituent of the strain was produced in submerged culture method, it was isolated and purified by XAD-2 and CM-Sephadex column chromatography. And it was found to be one of quinone type antibiotics.

• The Korean Journal of Mycology
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• v.13 no.2
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• pp.89-97
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• 1985

To find antibacterial strains of the soil microorganisms in Korea, they were isolated from the soil samples of different locations and screened for antibacterial activity against several standard microorganisms. An isolate among them had antibacterial activities against gram-positive and gram-negative bacteria. The examination of its morphological, biochemical, cultural and physiological characteristics according to the International Streptomyces Project methods showed that it belongs to the genus Streptomyces. This strain appears to be a novel strain when it was compared with those species of the genus which have been so far reported. The antibiotic metabolite was produced in the submerged culture of the strain. This metabolite was extracted from the culture filtrate and purified by ion-exchange column chromatography. Physico-chemical properties of the antibacterial metabolite were characterized.

• Journal of Microbiology and Biotechnology
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• v.32 no.7
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• pp.855-861
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• 2022

A white-pigmented, non-motile, gram-negative, and rod-shaped bacterium, designated CYS-02^T, was isolated from soil sampled at Suwon, Gyeonggi-do, Republic of Korea. Cells were strictly aerobic, grew optimally at 20-28℃ and hydrolyzed Tween 40. Phylogenetic analysis based on 16S rRNA gene sequence indicated that strain CYS-02^T formed a lineage within the family Comamonadaceae and clustered as members of the genus Variovorax. The closest members were Variovorax guangxiensis DSM 27352^T (98.6% sequence similarity), Variovorax paradoxus NBRC 15149^T (98.5%), and Variovorax gossypii JM-310^T (98.3%). The principal respiratory quinone was Q-8 and the major polar lipids contain phosphatidylethanolamine (PE), phosphatidylethanolamine (PG), and diphosphatidylglycerol (DPG). The predominant cellular fatty acids were C_16:0, summed feature 3 (C_16:1ω7c and/or C_16:1ω6c) and summed feature 8 (C_18:1ω7c and/or C_18:1ω6c). The DNA GC content was 67.7 mol%. The ANI and dDDH values between strain CYS-02T and the closest members in the genus Variovorax were ≤ 79.0 and 22.4%, respectively, and the AAI and POCP values between CYS-02^T and the other related species in the family Comamonadaceae were > 70% and > 50%, respectively. The genome of strain CYS-02^T showed a putative terpene biosynthetic cluster responsible for antioxidant activity which was supported by DPPH radical scavenging activity test. Based on genomic, phenotypic and chemotaxonomic analyses, strain CYS-02^T was classified into a novel species in the genus Variovorax, for which the name Variovorax terrae sp. nov., has been proposed. The type strain is CYS-02^T (= KACC 22656^T = NBRC 00115645^T).

• Geomechanics and Engineering
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• v.22 no.3
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• pp.219-226
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• 2020

Unconfined compression test (UCT) is widely conducted in laboratories to evaluate the mechanical behavior of frozen soils. However, its results are sensitive to the initial conditions of sample creation by freezing as well as the end-surface conditions during loading of the specimen into the apparatus for testing. This work compared ice samples prepared by three-dimensional and one-dimensional freezing. The latter created more-homogenous ice samples containing fewer entrapped air bubbles or air nuclei, leading to relatively stable UCT results. Three end-surface conditions were compared for UCT on ice specimens made by one-dimensional freezing. Steel disc cap with embedded rubber was found most appropriate for UCT. Three frozen materials (ice, frozen sand, and frozen silt) showed different failure patterns, which were classified as brittle failure and ductile failure. Ice and frozen sand showed strain-softening, while frozen silt showed strain-hardening. Subsequent investigation considered the influence of fines content on the unconfined compression behavior of frozen soil mixtures with fines contents of 0-100%. The mixtures showed a brittle-to-ductile transition of failure patterns at 10%-20% fines content.