• Journal of Ginseng Research
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• 제16권3호
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• pp.228-234
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• 1992

There has been general tendency to explain the traditional ginseng efficacy through the pharmacological and biochemical activities of ginsenosides. However, when we analyze the pharmacological and biological data on ginseng reported yet, we can easily arrive at the conclsion that most of the data on pharmacological and biological activities must have been obtained using impure ginsenoside samples, which should contain some non-saponin constituents as impurities. Based on the above back-ground, the non-saponin constituents of ginseng were studied in our laboratory. Phenolic substances including Maltol, Vanillic Acid, Salicylic Acid, Ferrulic Acid and Caffeic acid and impure ginsenoside samples were found to show strong antioxidant and anti-fatigue activities, while pure ginsenosides were devoid of the activities. Maltol, one of antioxidant components In Korean red ginseng drew a special interest due to its very low pro-oxidant activity. The antioxidant activity of ginseng may be considered as scientific basis for the antiageing activity which was described in traditional medicinal material book as "long-term medication of ginseng will improve bio-efficiency and extend life-span" The lignin components, another non-saponin consitutents, isolated from ginseng extract In our laboratory may eplain the hepato-protective activity of ginseng which has been repeatedly rtaimed as one of the efficacies of ginsenosides. The P-carboline alkaloids isolated in our laboratory as one of the non-saponin constituents of ginseng may play some pharmacological activities which should also be investigated. Present paper will include chemistry and biochemical aspects of the non-saponin constituents of ginseng with special interests for the explanation of traditional ginseng efficacy on modern scientific basis.fic basis.

• 한국동물위생학회지
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• 제26권1호
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• pp.39-50
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• 2003

Non-typhoidal Salmonella serovars remain a potential threat to human health and many animals including beef cattle, broiler chickens, and pigs which possible sources of non-typhoidal salmonellosis in human. In this study, the cecal contents of slaughtered pigs were examined for Salmonella serovar prevalence. The characteristics of the isolates, including antimicrobial resistance patterns and virulence genes, were studied along with the reference strain S typhimurium ATCC 13311. Out of 640 sample, 137 Salmonella(21.4%) were isolated and their serovar were identified S typhimurium 83 strains(60.6%), S agona 10 strains(7.3%), S schwarzengrund 4 strains(2.9%), S derby 4 strains(2.9%), S ayinde 1 strains(0.7%), and untypable 35 strains(25.5%). All 83 S typhimurium strains(100%) were multi-drug resistance to at least 7 antibiotics, and 20 strains(24.1%) of 83 isolates were R-type ACSSuT. Examination of virulent gene by PCR revealed that 73 S typimurium field isolates(88%) have a invA gene and 24 strains(28.9%) have a spvC gene. Consequently, S typhimurium infection in slaughtered pigs was relatively to appear high prevalence in their herds which suggested that it should be necessary for herd health monitoring and surveillance.

• 전력전자학회논문지
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• 제4권4호
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• pp.377-383
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• 1999

종래의 충전기 및 통신용 전원장치에 있어서 입력 역률을 개선시키기 위해 고 역률 컨버터(Power Factor Correction Circuit)가 제안되어 적용되고 있고, 이들 대부분 회로는 Hard Switching을 이용한 정류회로로, 입력역률 1제어와 입력전류를 정현파형을 만들 수 있지만 Switching Noise에 의한 전자파장해(EMI)와 스위칭손실 등의 문제를 안고 있다. 또한, 절연된 DC 출력전압을 얻기 위해서는 고 역률 컨버터 후단에 절연된 DC/DC 컨버터가 적용되어야 함으로써, 주 회로 및 제어회로가 다단으로 구성되는 등 복잡화되는 단점이 있었다. 본 논문에서는 이러한 단점을 극복하기 위해 역률보정회로(PFC)를 갖는 절연된 Single Stage 무손실 스너버적용 고주파 소프트 스위칭 컨버터를 제안하고자 한다.

• Earthquakes and Structures
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• 제4권4호
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• pp.341-363
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• 2013

Earthquake response calculation, parametric analysis and seismic parameter optimization of base-isolated structures are some critical issues for seismic design of base-isolated structures. To calculate the earthquake responses for such non-symmetric and non-classical damping linear systems and to implement the earthquake resistant design codes, a modified complex mode superposition design response spectrum method is put forward. Furthermore, to do parameter optimization for base-isolation structures, a graphical approach is proposed by analyzing the relationship between the base shear ratio of a seismic base-isolation floor to non-seismic base-isolation one and frequency ratio-damping ratio, as well as the relationship between the seismic base-isolation floor displacement and frequency ratio-damping ratio. In addition, the influences of mode number and site classification on the seismic base-isolation structure and corresponding optimum parameters are investigated. It is demonstrated that the modified complex mode superposition design response spectrum method is more precise and more convenient to engineering applications for utilizing the damping reduction factors and the design response spectrum, and the proposed graphical approach for parameter optimization of seismic base-isolation structures is compendious and feasible.

• 대한의생명과학회지
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• 제19권2호
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• pp.132-141
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• 2013

Mycobacterium isolates were retrospectively identified, antibiotics susceptibility test results and basic clinical data were analyzed for the 715, excepted 308 in 1,023 specimens, from a mycobacterial laboratory at a tertiary care hospital from September 2002 to December 2008. Their male to female ratio was 1.12 to 1 (379 male, 336 female). The median age of study population was 47 years (range from 10 to 93 years). Distribution of Mycobacterium species was 90.1% of total were isolates Mycobacterium tuberculosis, and 9.9% of the total non-tuberculosis Mycobacterium isolated, and Among nontuberculosis Mycobacterium isolates, 60.6% were Mycobacterium avium complex, 14.1% were isolates Mycobacterium abscessus, and 12.7% were isolates Mycobacterium intracellulare. Among 526 Mycobacterium tuberculosis isolates, 81.7% isolates were susceptible to first line antibiotics, 18.3% were resistant to one or more antibiotics. Non-tuberculosis Mycobacterium isolates, all were resistant to two or more antibiotics. Multi-antibiotic resistant tuberculosis rate was show 10.2% of total specimens. Isolated Mycobacterium species, 19.2% were multi-antibiotic resistant tuberculosis, and the rate of nontuberculosis Mycobacterium resistant to isoniazid and rifampin was very highly 84.5%. Thus among acid fast bacilli culture positive cases, Mycobacterium tuberculosis and non-tuberculosis Mycobacterium were must exactly identification and antibiotic sensitivity test. It was considered to help to select of the antibiotic in preventive medicine.

• The Plant Pathology Journal
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• 제18권2호
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• pp.63-67
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• 2002

To understand plant-pathogen interactions, a complete set of hot pepper genes differentially expressed against pathogen attack was isolated. As an initial step, hundreds of differentially expressed cDNAS were isolated from hot pepper leaves showing non-host resistance against bacterial plant pathogens (Xanthomonas campestris pv. glycines and Pseudomonas syringae pv. syringae) using differential display reverse transcription polymerase chain reaction (DDDRT-PCR) technique. Reverse Northern and Northern blot analyses revealed that 50% of those genes were differentially expressed in pepper loaves during non-host resistance response. Among them, independent genes without redundancy were micro-arrayed for further analysis. Random EST sequence database were also generated from various CDNA libraries including pepper tissue specific libraries and leaves showing non-host hypersensitive response against X. campestris pv. glycines. As a primary stage, thousands of cDNA clones were sequenced and EST data were analyzed. These clones are being spotted on glass slide to study the expression profiling. Results of this study may further broaden knowledge on plant-pathogen interactions.

• Restorative Dentistry and Endodontics
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• 제19권2호
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• pp.568-584
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• 1994

Bacteria have been regarded as major etiolgic factors in root canal infections. Infected root canal flora from thirteen patients who had visited to conservative department of Wonkwang dental hospital were cultured on blood agar plates. Cultued microorganisms were isolated and identified with Gram stain and biochemical tests using Vitek Systems(BioMeriux, MO, USA); Antibiotic susceptibillity was performed with disk diffusion and broth microdilution using Vitek Systems. Gram positive cocci(65 %) were predominant, which were composed of 6 Streptococcus viridans group, 5 Staph. spp., and 4 Enterococcus faecium, in the isolatd 23 strains. Gram negative rods (26 %) were the next common bacteria, which were composed of 5 non - fermentative Gram negative rods, and 1 Enterobacter cloacae. Most strains of S. viridans group and E. faecium were susceptible to antibiotics including penicillin. But strains of Staphylococcus spp. and non - fermentative Gram negative rods showed marked resistance to antibiotics except tetrancyclin and cefotaxime. Most results between disk diffusion and microdilution were all agreed, but the results of non - fermentative Gram negative rods were susceptible to cefotaxime in disk diffusion method but resistant in microdilution.

• 한국환경과학회지
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• 제8권6호
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• pp.653-660
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• 1999

The flow of non-rotation atmosphere with uniform stratification and wind past an isolated three dimensional topography obstacle is investigated with three-dimensional hydrostatic and non- hydrostatic numerical model. The characteristic of turbulence created the back of topography obstacle is usually defined by Froude number which is the function of upstream wind speed, the height of topography obstacle, and atmospheric stability. Turbulence tends to be formed more easily at the non-hydrostatic model than hydrostatic model. Especially, the difference between flow patterns of two models generated by isolated obstacle is more clear under low Froude number. The difference of flow patterns can be only seen at relatively low altitude, but at high altitude the patterns of two models are almost same. In this research, wind velocity in the parameters related with Froude number have great sensitivity at responsibility of numerical models. and slop of obstacle is also important factor at the flow pattern regardless of the species of numerical model

• 한국토양비료학회지
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• 제25권4호
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• pp.394-400
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• 1992

밭 토양에서 분리한 280개 균주의 방선균을 형태적 및 생리적특성으로 구분한 결과 15개 군으로 분류되었으며, 이들 각 군들중 Streptomyces속은 12개군의 87.2% 그리고 Non-Streptomyces속은 3개군의 12.8%로 확인되었다. 또한 전체 분리균주 중 포자체의 Spiral chain형태의 Streptomyces속이 75%로서 우점하였다. Streptomyces속의 12개군을 전자현미경상에서 포자체의 표면형태를 관찰한 결과 2개군은 Spiny형태를 보였고, 10군은 Smooth형태를 갖는 것으로 동정되었다. 또한 분리 동정한 방선균 15개 군을 E. coli. P. aeruginosa 및 S. aureus의 3개 시험균주에 대하여 항균력을 검정한 결과로는 E. coli에서 S-6균주가 $6.23r/m{\ell}$이고 P. aeruginosa에는 S-9균주가 $8.46r/m{\ell}$이며 S. aureus에는 S-2균주가 $7.24r/m{\ell}$로서 다른 방선균에 비하여 가장 높은 항균력을 나타내었다.

• 전력전자학회논문지
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• 제14권4호
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• pp.315-322
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• 2009

기존의 부스트 컨버터는 출력 전압이 커질수록 스위치와 다이오드의 전압, 전류 스트레스가 커지고 다이오드 역 방향회복에 의한 서지로 인해 실제 사용 가능한 승압비가 제한된다. 본 논문에서는 고승압 응용에 적합한 새로운 비절연 부스트 컨버터를 제안한다. 제안한 컨버터는 듀티비 0.5로 약 6배의 승압비를 가지며 CCM에서도 ZVS 스위칭이 가능하므로 넓은 ZVS 영역을 갖는다. 또한 스위치와 다이오드 전압정격이 출력전압의 1/3로 작고 인터리빙이 가능하여 입출력 수동소자의 정격도 작다. 다이오드도 ZCS 턴오프 동작으로 인해 역방향 회복에 의한 서지가 거의 없다. 제안하는 컨버터의 동작원리를 설명하였고 이론적 해석과 시뮬레이션 및 실험을 통해 타당성을 검증하였다.