• 한국지반공학회논문집
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• 제17권6호
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• pp.235-244
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• 2001

액상화는 비배수조건에서 흙 강도의 갑작스러운 감소에 기인한다. 이러한 흙 강도의 손실은 과잉간극수압의 발현과 관련된다. 본 연구에서는 최대 및 최소간극비에 영향을 미치는 세립분 함유량이 조사되었다. 또한 포화된 실트질 모래에 대한 정적 및 동적 삼축시험의 결과를 제시하였다. 이들 시험은 액상화강도와 정적 및 동적 거동 특성을 평가하기 위해 수행되었다. 시료는 새만금 유역에서 채취되었으며 공기건조되었다. 결과를 요약하면 다음과 같다. 1) 최대 및 최소간극비선은 유사한 경향으로 나타났다. 2) 최대 및 최소간극비는 20~30%의 세립분 함유량에서 얻어졌다. 3) 구속압력과 과압밀비가 증가할수록 액상화에 대한 저항은 증가하였다. 4) 불안정마찰각은 초기상대밀도의 증가와 함께 커졌다. 5) 유효응력비가 증가함에 따라 액상화에 대한 저항은 감소하였다.

• 대한조선학회지
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• 제19권4호
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• pp.31-37
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• 1982

Developing a minimum wave resistance hull form which is satisfying the given requirements such as displacement and speed is one of the important problems in ship hydrodynamics. The theoretical approach conducted by Pien was successful in developing an optimized hull form, however, which can not be applied directly to practical hull form without manual lines fairing process. To avoid this difficulty, source distribution which arrived after the optimization was put into a fictitious restricted channel and as a result practicably modified hull form was derived by stream line tracing. The wave resistance of the hull thus obtained was calculated by solving the simplified integral equation suggested by Kan. The resistance at design point is almost same with that of the original hull which was represented by source distribution on the vertical rectangular center plane. It is therefore recommended to use the derived hull form for the hull which obtained after manual lines fairing process at Pienoid method. Further researches both in theory and experiment are necessary before this concept is put into practical application.

• 한국수산과학회지
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• 제52권6호
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• pp.587-595
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• 2019

Eighty-three Vibrio parahaemolyticus isolates from surface seawater in Gomso Bay on the west coast of Korea, and commercial fisheries from Gunsan fisheries center were analyzed for the presence of virulence genes and susceptibility to 30 different antimicrobials. All 83 isolates were examined for the presence of two virulence genes (tdh or trh) using polymerase chain reaction; however, neither gene was found in any of the isolates. A disk diffusion susceptibility test, showed that all of the strains studied were resistant to clindamycin, oxacillin, ticarcillin, and vancomycin, and also revealed varying levels of resistance to ampicillin (98.8%), penicillin G (95.2%), streptomycin (20.5%), cefoxitin (14.5%), amikacin (6.0%), cephalothin (4.8%), and erythromycin (3.6%). However, all of the strains were susceptible to 19 other antimicrobial agents, including cefepime, cefotaxime, chloramphenicol, gentamycin, nalidixic acid, sulfamethoxazole/trimethoprim, and trimethoprim. All 83 isolates (100%) were resistant to five or more classes of antimicrobials, and two strains exhibited resistance to ten antimicrobial agents. The average minimum inhibitory concentrations against V. parahaemolyticus of clindamycin, oxacillin, ticarcillin, and vancomycin were 55.9, 98.3, 499.3, and 44.3 ㎍/mL, respectively. These results provide new insight into the necessity for seawater sanitation in Gomso Bay and commercial fisheries, and provide evidence to help reduce the risk of contamination by antimicrobial-resistant bacteria.

• International Journal of Naval Architecture and Ocean Engineering
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• 제8권2호
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• pp.169-176
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• 2016

In this paper, further research is carried out to investigate the resistance encountered by an icebreaking vessel travelling through level ice and channel ice at low speed range. The present paper focuses on experimental and calculated ice resistances by some empirical formulas in both level ice and channel ice. In order to achieve the research, extra model tests have been done in an ice basin. Based on the measurements from model test, it is found that there exists a relationship between ice resistance, minimum ice load, maximum ice load and the standard deviation of ice load for head on operation in level ice. In addition, both level ice resistance and channel ice resistance are calculated and compared with model test results.

• 수산해양기술연구
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• 제41권3호
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• pp.222-226
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• 2005

A series of model tests carried out at the CWC of WJFEL for the purpose of prediction of resistance for the performance and improvement of resistance by attaching appendage for the ship of 50 knots class planing hull. The resistance performance evaluation has been carried out for the bare hull and for the appendage hull with two different depth of vertical type wedges. In the bare model test, trim and sinkage is calculated for the planing hull and the resistance is calculated. For minimizing the resistance, wedge appendage is attached and tested. Analysis and tests shows that for a 12.5mm wedge, resistance is minimum and overall power tallied to 5636ps.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 1995년도 추계학술강연 및 발표대회 강연 및 발표논문 초록집
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• pp.9-9
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• 1995

MATERIAL AND PROCESS VARIABLES THAT STRONGLY AFFECT THE CORROSION RESISTANCE OF PA4 STAINLESS STEELS, INCLUDE : ALLOY COMPOSITION, POWDER CLEANLINESS, NITROGEN, OXYGEN AND GARBON CONTENTS, CHROMIUM DEPLETION DUE TO SURFACE EVAPORATION AND SINTERED DENSITY. THE OPTIMUM PROCESS PARAMETERS FOR DELUBRICATION AND SINTERING THAT RESULT IN LOWEST LEVELS OF NITROGEN, OXYGEN AND CARBON AND MINIMUM LEVELS OF CHROMIUM DEPLETION WILL BE PRESENTED, FOR A NUMBER OF AUSTENTIC AND FERRITIC STAINLESS STEELS. THE EFFECT OF SINTERED DENSITY ON THE CORROSION RESISTANCE OF BOTH AUSTENITIC AND FERRITIC GRADES OF STAINLESS STEEL WILL ALSO BE COVERED.

• 대한조선학회지
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• 제4권1호
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• pp.49-54
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• 1967

The authors considered the effects of trim in the small coastal passenger boat upon resistance in this paper. Any change of trim no matter how small, necessarily produces some effect upon resistance. The relations between the resistance coefficients and trim were investigated through the towing test of the Model $MCI-P_1-65$, Korean Standardized Ship, GT 70 tons passenger boat in the gravitational tank. The Lines of the Model are given in Fig. 1. Principal dimensions and other characteristics vary with the trim in general. Those values varied with the trim for $MCI-P_1-65$ are tabulated in table 1. The resistance was measured at five conditions such as even keel, 0.0273L, (original designed trim) 0.0473L, 0.0663L, 0.0873L trim by the stern, fixing the displacement corresponding to the designed load water line. Model was made of wood in length of 3.5 feet coated with varnish, and without appendages. As the artificial turbulent stimulator, the sand strip method was used. The results of model towing tests, correcting to water temperature of $70^{\circ}F$, were expanded to full scale using the Schoenherr's friction formula and surface roughness allowance coefficient of 0.0004. The authors point out, the following results. 1) Optimum trim which gives the minimum resistance exists for every speed at constant displacement and each comes to the same value. For $MCI-P_1-65$ optimum trim is 0.0673L trim by the stern(Fig.4-The cross curves of the resistancecoefficients). 2) At constant displacement, when LCB(longitudinal position of center of buoyancy) varies with the trim, there exists optimum value of LCB which gives minimum resistance for every speed and each comes to the same value. For $MCI-P_1-65$ optimum position of LCB is 8%L aft from midship section (Fig.6).

• Journal of Microbiology and Biotechnology
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• 제34권4호
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• pp.871-879
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• 2024

Our group had isolated Bifidobacterium breve strain BS2-PB3 from human breast milk. In this study, we sequenced the whole genome of B. breve BS2-PB3, and with a focus on its safety profile, various probiotic characteristics (presence of antibiotic resistance genes, virulence factors, and mobile elements) were then determined through bioinformatic analyses. The antibiotic resistance profile of B. breve BS2-PB3 was also evaluated. The whole genome of B. breve BS2-PB3 consisted of 2,268,931 base pairs with a G-C content of 58.89% and 2,108 coding regions. The average nucleotide identity and whole-genome phylogenetic analyses supported the classification of B. breve BS2-PB3. According to our in silico assessment, B. breve BS2-PB3 possesses antioxidant and immunomodulation properties in addition to various genes related to the probiotic properties of heat, cold, and acid stress, bile tolerance, and adhesion. Antibiotic susceptibility was evaluated using the Kirby-Bauer disk-diffusion test, in which the minimum inhibitory concentrations for selected antibiotics were subsequently tested using the Epsilometer test. B. breve BS2-PB3 only exhibited selected resistance phenotypes, i.e., to mupirocin (minimum inhibitory concentration/MIC >1,024 ㎍/ml), sulfamethoxazole (MIC>1,024 ㎍/ml), and oxacillin (MIC >3 ㎍/ml). The resistance genes against those antibiotics, i.e., ileS, mupB, sul4, mecC and ramA, were detected within its genome as well. While no virulence factor was detected, four insertion sequences were identified within the genome but were located away from the identified antibiotic resistance genes. In conclusion, B. breve BS2-PB3 demonstrated a sufficient safety profile, making it a promising candidate for further development as a potential functional food.

• Journal of Microbiology and Biotechnology
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• 제30권8호
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• pp.1180-1183
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• 2020

The prevalence and characterization of plasmid-mediated quinolone resistance (PMQR) determinants in ciprofloxacin-resistant Escherichia coli isolated from a Korean commercial layer farm were studied. A total of 45 ciprofloxacin-resistant E. coli isolates were recovered and all isolates were multidrug-resistant. Eight isolates have the PMQR genes aac(6')-Ib-cr, qnrS1, and qnrB4, and seven isolates exhibited double amino acid exchange at both gyrA and parC, and have high fluoroquinolone minimum inhibitory concentrations. Five transconjugants demonstrated transferability of PMQR and β-lactamase genes and similar antimicrobial resistance. Because PMQR genes in isolates from commercial layer chickens could enter the food supply and directly affect humans, control of ciprofloxacin resistance is needed.

• 생약학회지
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• 제40권1호
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• pp.70-76
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• 2009

Thirty six essential oils from herb drugs entered in Korean official formulary, which are frequently used in oriental region, were tested for antibiotic resistance inhibition. When the oils were combined with ampicillin (Am) or amoxicillin (Amx) they showed significant inhibitory effects on the growth of multi-drug resistant Staphylococcus aureus SA2 in considerably low concentration. The most effective combinations were oils from Acanthopanacis Cortex ($0.49{\mu}g/mL$) with Am and Cnidii Rhizoma and Lonicerae Flos (2.77 and $2.79{\mu}g/mL$, respectively) with Amx as shown in minimum resistance inhibitory concentrations.