• 한국약용작물학회지
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• 제24권3호
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• pp.198-206
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• 2016

Background: Electrical conductivity (EC) and pH are important features of nutrient solution, affecting both growth and quality of crops by altering nutrient uptake. Methods and Results: The pH values of nutrient solutions were controlled at 5.0, 5.5, 6.0, 6.5 and EC values were controlled at 0.68, 0.84, 1.23, 1.41 dS/m. Gingesng root weights were higher during the initial growth period when the plants were treated with low pH and low EC nutrient solutions. However, the higher pH and EC levels, the greater the increase in the rate of root weight between the initial and middle growth periods. The highest ginsenoside amount changed during growth period. The total ginsenoside amount was highest in the root, and the lowest in leaves at 45 and 90 days after treatment, respectively, with solution at a pH of 6.0. After 135 days of treatment, the highest total ginsenoside amount was detected in root treated with soluton with EC values of 1.23 dS/m. Conclusions: For the cultivation of ginseng using a nutriculture system, the pH and EC values of nutrient solutions should to be controlled based on the stage of growth and targeted plant organ (root or leaves).

• Restorative Dentistry and Endodontics
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• 제43권3호
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• pp.31.1-31.7
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• 2018

Despite considerable focus on the regenerative endodontic treatment of immature teeth with necrotic infected pulps and apical periodontitis, little data exist with regard to its possible implementation in necrotic permanent teeth with complete apical and radicular development. The present report describes the procedures and outcome of a regenerative endodontic treatment approach in 2 previously-traumatized incisors with closed apex with apical periodontitis. A 2-visit treatment procedure was employed. At initial visit, the root canals were copiously irrigated, followed by placement of a triple antibiotic paste containing ciprofloxacin, metronidazole, and clindamycin into the root canals. After 4 weeks, the antibiotic paste was removed, and apical bleeding was initiated with size 10 hand files beyond the apices. The root canals were coronally sealed with mineral trioxide aggregate, and the access cavities were restored with bonded resin composite. At post-operative 60 months, both teeth were remained asymptomatic, with the recall radiographs showing complete resolution of apical radiolucency and reestablishment of periradicular tissues. In both teeth, the dimensions of root space remained unchanged as verified by image analysis. The revitalization protocol utilizing root canal disinfection and induced apical bleeding in necrotic, closed-apex incisors may offer a clinically acceptable alternative to conventional root canal treatment.

• The Plant Pathology Journal
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• 제15권2호
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• pp.127-130
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• 1999

Cytological changes of cowpea root at the early stage of root nodule formation (within 5 days after inoculation) were viewed by light and electron microscopy. The root region affected by the rhizobial infection, which was composed of a redial array of cortical cells, had prominent cell divisions, mostly anticlinal in the inner cortical cells and in addition oblique and periclinal in the outer cells. An infected root hair cell (or root hair-producing epidermal cell) had numerous infection threads and degenerated cytoplasm. Module meristem was formed adjacent to the infected root hair cell, and characterized by dense cytoplasm, prominent nucleus, numerous small vacuoles, and increased plastids, containing infection threads as well. Bacterial cells were dividing inside the infection thread, the wall materials of which appeared to be dissolved ad accumulated in small vacuoles. inner cortical cells contiguous to the nodule meristem appeared to be actively dividing and dedifferentiating; however, they were not infected by the rhizobia. These structural characteristics are similar to those in the Bradyrhizobium-soybean association previously reported, and may reflect the similar cytological process in cowpea in the early nodule formation.

• 한국지하수토양환경학회지:지하수토양환경
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• 제24권5호
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• pp.1-10
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• 2019

The effects of liquid phase ozonation on seed dormant alleviation and subsequent seedling growth were studied using two plant seeds of Indian jointvetch (Aeschynomene indica L.) and Indian mallow (Abutilon avicennae Gaertn.). At a constant ozone concentration ($80g/m^3$), contact time varied from 10 to 60 min with 10 min interval. Germination rate, root length, and specific root length were compared after 3-day incubation on gel-medium. The germination rate increased significantly (p<0.05) in the 50 min treatment of Indian mallow by 30% compared to the control. Enhanced root elongation was observed in the seeds of 30 min treatment of Indian jointvetch and 30~50 min treatment of Indian mallow. Specific root length, an indicator of environmental change, did not show significant changes, suggesting the level of ozone treatment has no adverse effect on seedling development. The results indicate that liquid phase seed ozonation can be an effective on-site germination alleviation method in the application of phytoremediation.

• 식물병연구
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• 제6권1호
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• pp.23-26
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• 2000

봄배추 무사마귀병의 감염시기별 피해정도를 포장시험으로 조사하였다. 정식후 감염시기가 빠를수록 수량에 대한 피해가 컸으며 정식후 20일 이전 감염배추는 수확전 완전히 고사하였고 정식후 30일에 감염된 배추는 수확시까지 외관상 건전한 생육을 보였으나 포기무게가 건전주의 59%에 불과하여 상품성이 없었다. 정식 40일 이후 감염배추는 수량에 대한 영향이 없었다. 이병배추는 감염후 시간이 경과할수록 잔뿌리의 생성이 감소되어 생육후기에는 거의 잔뿌리가 없었으며 뿌리의 신장도 건전주에 비해 1/2∼1/3 수준으로 감소하였다. 뿌리혹은 감염 20일후에 처음으로 관찰되어 이후 급속히 비대하였으며 최초 생성 20일후에 최대치에 달하였고 그후 혹뿌리의 부패로 근중이 감소하기 시작하여 수확기에는 건전주보다 낮아졌다. 뿌리혹의 발달 및 부패속도는 감염시기와 상관없이 배추생육기의 온도가 높아질수록 빨라지는 경향을 보였다. 식물체 위조는 뿌리혹이 생성된지 10일후에 처음으로 관찰되었으며 그후 10일경부터 혹이 부패하기 시작하여 열흘동안 완전히 부패 소실되었고 식물체도 고사하였다. 따라서 봄배추의 무사마귀병 포장정식시 감염은 20일간의 잠복기 20일간의 혹비대기를 거쳐 10일동안의 혹부패기, 그후의 토양내 잔존기로 구분이 가능하였다.

• 치과방사선
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• 제27권2호
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• pp.15-25
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• 1997

This study was performed to prepare the quantitative method of judging the sensitive prognosis of chronic apical periodontitis as early as possible. The subjects were 25 cases with periapical radiolucencies of which were treated with endodontic treatment. Serial radiographs were taken by standardized method longitudinally. The density slice function of digital radiographic system were employed for quantitative and longitudinal assessment of the radiolucent area and the condensing osteitis simultaneously. Obtained results were as follows: 1. The amount of bone repair after endodontic treatment could be detected quantitatively by the density slice function of digital radiographic system. 2. Within the 6-week period after root canal filling, the prognosis could be evaluated by assessment both radiolucent area and condensing osteitis on digital radiographic system. 3. The pattern of bone repair showed peripheral type in most cases from the 6th week after root canal filling. 4. In longitudinal change, bone repair showed two patterns; the succeeding reduction of radiolucent area showing the increase of condensing osteitis in size till 6th week and following by static state or reduction tendency and the reduction following the initial increase of both areas. 5. Cases with pulpitis by trauma showed initial increase of condensing osteitis at 2nd week, marked reduction of radiolucent area and condensing osteitis at 6th week, and approximately normal bone state at 8th week after root canal filling.

• 한국식품과학회지
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• 제37권6호
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• pp.1012-1017
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• 2005

게맛살로부터 분리한 주요 부패세균은 내열성 포자를 형성하는 Bacillus subtilis와 Bacillus licheniformis로 동정되었다. 게맛살의 제조 공정상 가열 처리 과정에서 B. subtilis와 B. Licheniformis 등 내열성 포자를 형성하는 균을 완전히 사멸시키기는 어려우며, 살아남은 포자는 유통과정 중, 적정 온도와 시간이 경과함에 따라, 영향 세포로 발아하여 게맛살의 부패에 영향을 미친다. 이러한 부패세균의 증식에 있어서 초기균수와 온도의 영향을 조사한 결과, 초기균수에 따른 최대증식속도상수(k)와 유도기(LT), 세대시간(GT)은 유의적인 차이가 없었으며, 온도의 영향이 지배적인 것으로 나타났다. 또한 본 실험에서 유도기(LT)와 온도의 관계는 $L(hr)=2.5219e^{-0.2467{\cdot}T}$의 관계가 성립하며, square root model과 polynomial model을 이용, 온도와 초기균수에 대한 최대증식속도상수(k)를 정량화한 정량평가모델을 개발하였으며, 그 식은 다음과 같다. $$Square\;root\;model:\;{\sqrt{k}}=0.0267\;(T-3.5089)$$ $$Polynomial model:\;k=-0.2160+0.0241T-0.01999A_0$$ 온도와 초기균수에 대한 최대증식속도상수(k)의 정량평가모델로부터 특정온도와 초기 균수에서 최대증식속도상수(k)를 계산할 수 있으며, 계산된 최대증식속도상수(k)를 균의 기본 증식 모델인 Gomperz model에 적용하여 균의 성장을 예측할 수 있었다.

• 제어로봇시스템학회논문지
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• 제5권4호
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• pp.379-384
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• 1999

In this paper, we present a new time-varying sliding surface to achieve fast and robust tracking of higher-order uncertain systems. The surface passes through an initial error, and afterwards, it moves towards a predetermined target surface by means of a variable named by sliding surface gain and its intercept. Specifically, the sliding surface gain is determined so that its initial value can minimize a shifting distance of the surface and that the system roots in sliding mode can follow certain stable trajectories. The designed sliding mode control forces the system errors to stay always on the proposed surface from the beginning. By this means, the system remains insensitive to system uncertainties and disturbances for the whole time. To illustrate the effectiveness of the proposed method, the comparative study with conventional time-invariant sliding mode control is performed.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1792-1797
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• 2007

This paper try to find root-cause of failure in a connector used in transmitting signals for throttle body control in automotives by analyzing possible failure causes and performing experiments to simulate the cable failure in field. The connector comprises fins, wires, and case moldings. The failure is due to degradation of initial clamping force required fixing fins and wires in the connector. Expansion and compression of the case molding material surrounding fins would cause the degradation. Investigations of strict initial claming force and control of thermal expansion property of the molding are required to prevent the failure.

• Journal of Plant Biology
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• 제37권3호
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• pp.357-363
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• 1994

An expreiment with non-nodulating alfalfa (Medicago sativa L.) plants was designed to investigate the changes in protein contents and the activities of proteolytic enzymes during a regrowth period of 24 d. Shoot removal caused a depression of root growth and significantly reduced protein contents in roots. An initial decline of root proteins for the first 10 d was followed by a rapid recovery from d 11 to 24. The major increase of regrowing shoot weight occurred also from d 11. The activities of aminopeptidase and endoprotease slightly decreased in regrowing leaves, while protein contents remains stable after shoot removal. Roots exhibited source behaviour with a rapid increase of endoprotease activities for the first 10 d of regrowth; about a 370% increase over the initial level was observed. Increase in endoprotease activity in roots coincided with the time of protein remobilization after shoot removal, indicating the important role of endoproteases in protein degradation.