• 한국작물학회:학술대회논문집
• /
• 한국작물학회 2017년도 9th Asian Crop Science Association conference
• /
• pp.231-231
• /
• 2017

Drought limits rice production under upland condition. This study quantified the effect of rhizobacteria inoculation on rice root system developmental response to drought and its role in maintaining high soil water use, and dry matter production under drought using NSIC Rc192 (rainfed lowland rice variety). The source of inoculant was Streptomyces mutabilis, a recently isolated rhizobacteria containing plant growth promoting compounds such as ACC deaminase, indole-3-acetic acid and phosphatase (Cruz et al., 2014, 2015). In the first experiment, pre-germination inoculation of seeds with S. mutabilis significantly increased the shoot and root (radicle) length as well as root hair lengths, relative to the non-inoculated control. In the second experiment, rice plants inoculated with S. mutabilis and grown in rootbox with soil generally had greater total root length under drought regardless of the timing of inoculations, relative to the non-inoculated control. Consequently, improved root system development contributed to the increase in soil water uptake under drought and thus, dry matter production. Among inoculation treatments, one-time inoculation of S. mutabilis either at pre-germination or pre-drought stress at 14 days after sowing (DAS), had significantly greater shoot dry matter production than three-time inoculation at pre-germination, at thinning (3 DAS) and at pre-drought (14 DAS). This study demonstrated the effectiveness of rhizobacteria (S. mutabilis) containing growth promoting compounds for enhancing drought dehydration avoidance root traits and improving the growth of rice plants under drought condition.

• 한국소음진동공학회논문집
• /
• 제23권2호
• /
• pp.105-111
• /
• 2013

Whirl tower test is conducted basically during helicopter rotor system development process. And for whirl tower test of rotor hub system, new design blade or existing blade which is remodeled for new rotor hub system is used. Because of simple shape and efficient aerodynamic characteristic, BO-105 helicopter blade is used for helicopter rotor hub development project widely. Originally BO-105 blade is used for hingeless hub system and blade root is used to flexure. So flap stiffness and lag stiffness at blade root area is relatively low compare with airfoil area. So, in order to apply the BO-105 blade to bearingless hub, blade root area have to be reinforced. And in this process, blade root area's section property is changed. In this paper, we suggest reinforcement method of BO-105 blade root area and study dynamic characteristic of bearingless rotor system with reinforcement BO-105 blade.

• 한국농업기계학회:학술대회논문집
• /
• 한국농업기계학회 1996년도 International Conference on Agricultural Machinery Engineering Proceedings
• /
• pp.792-801
• /
• 1996

A thinning algorithm -based image analysis technique was developed to measure corn root lengths. The root length measurement method was evaluated by comparing thread lengths measured by the image analysis system with actual thread lengths. The length measurement method accurately estimated actual thread lengths (less than 2% calculated error). Also, a rapid root length density measurement procedure, which utilizes the above root length measurement method, was developed to estimate corn root length density without washing the roots. Root length densities estimated from the cut soil surface of core samples taken from the field were paired with the root length densities determined from washed roots from the same soil core sample. A linear relationship between these two values was expected and was found. Eliminating the root washing procedure reduces the time required for measuring corn root length density substantially.

• 한국작물학회:학술대회논문집
• /
• 한국작물학회 2017년도 9th Asian Crop Science Association conference
• /
• pp.230-230
• /
• 2017

About 200 rice varieties for irrigated and rainfed lowland ecosystems were released in the Philippines, which were bred for improving yield under favorable conditions. Root plasticity plays key roles in maintaining crop productivity under abiotic stressed conditions. We hypothesized that some of these varieties possess root plasticity traits in response to water stressed conditions. This study aimed to evaluate the root system development and dry matter production of 14 randomly selected rice varieties (6 irrigated lowland and 9 rainfed varieties) under progressive drought (PDR) and soil moisture fluctuations (SMF) stress conditions. Two experiments were done in rootbox and line source sprinkler systems (LSS). Each of the varieties was subjected to well-watered (WW), PDR and SMF conditions during vegetative stage in rootbox system while the same genotypes were subjected to different intensities of drought stress under LSS. Under rootbox system, PDR and SMF significantly reduced shoot dry matter production in all varieties relative to their WW controls. Among varieties, NSIC Rc238 (irrigated lowland) showed the least reduction in shoot dry weight (SDW) in both PDR (by 11.8%) and SMF (by 26.9%) conditions. Less reductions in SDW of NSICRc238 were partially attributed to the promotion of L-type lateral roots, thus increasing total lateral root length by 24.2% and 30.7% under PDR and SMF, respectively. In LSS, SDW of NSIC Rc238 under mild drought stress (16-21% soil moisture content (SMC) had 31.8% reduction relative to its WW control (${\geq}22%SMC$) and had lower sensitivity drought index. Compared with the IR64 susceptible check and NSIC Rc9 tolerant check, NSIC Rc238 had higher SDW by 90.8% and 38.6%, respectively. Furthermore, no rainfed lowland varieties included in the experiment performed well under different water stress treatments. The results implied that some other irrigated lowland rice varieties may also possess drought dehydration avoidance root plasticity traits under water-stressed growing environments.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2007년도 추계 학술논문 발표대회
• /
• pp.119-123
• /
• 2007

Recently, the green roofs market is active, but most constructors use former waterproofing method. So there are a lot of problems in the sub-organization of the green roofs system. I studied to use the block panel for the sub-organization of the green roofs system and I tested about the effectiveness of waterproofing, root barrier, drainage, and insulation. I have not found any problems about waterproofing, root barrier, drainage, and insulation in the results. The sub-organization of the green roofs system using the block panel is effective for waterproofing, root barrier, drainage, and insulation. We can apply it to the dried and unified execution technology.

• 한국초지조사료학회지
• /
• 제17권4호
• /
• pp.345-350
• /
• 1997

수정된 Lincoln용액을사용하여 여러가지 목초의 상대생장율, 뿌리/지상부(RlS)비율, 상대적 뿌리 용적 및 표면적 등을 동시에 비교하기 위하여 수경재배법을 개발하였다. 수정된 Lincoln 용액에서 19가지 초종이 모두 잘 자랐으며, 뿌리특성 연구에 긴요하게 이용될 수 있었다. 상대생장율은 조사기간 동안 이상적으로 일정 값을 유지하며 같은 식물체로 성공적으로 측정할 수 있었다. Group 간과 마찬가지로 group 내에서도 초종간 RlS율에 큰 차이가 있었다. 뿌리 조직밀도는 두과목초나 herb보다 화본과에서 낮았다. 뿌리 면적지수는 화본과 목초와 herb가 높았는데 이 면적지수는 각각 다른 초종의 상대척 根界 평가에 유용하게 이용될 수 있을 것으로 사료되었다.

• Journal of Forest and Environmental Science
• /
• 제10권1호
• /
• pp.8-24
• /
• 1994

수목(樹木)의 뿌리는 수목(樹木)의 생장(生長)과 토양(土壤)의 구조개선(構造改善)에 밀접한 관계가 있음에도 불구하고 지하부(地下部)에 위치하고 있으므로 연구가 미진한 상태이다. 따라서 각 수종(樹種)의 근계(根系)의 발달상태를 파악하는 것은 그 수종(樹種)의 특성 파악과 뿌리가 지표고정(地表固定)에 미치는 영향을 파악하는데 기초자료로 활용할 수 있다. 본 연구에서는 강원도(江原道) 소나무림(林)의 특성을 파악하기 위한 기초연구의 일부로서 일차적으로 강원대학교(江原大學校) 구내(構內) 소나무림(林)의 근계(根系) 형태(形態) 및 분포(分布)에 대하여 규명하였다. 5개의 공시목(供試木)에 대해 조사한 결과 뿌리의 형태(形態)는 수평근(水平根)이 잘 발달되어 있었다. 뿌리의 분포(分布)에 있어서 크기별로는 세근(細根)은 대부분이 점재(点在)(+)하고 있었음, 태근(太根)은 0.2cm가 대부분이었다. 깊이별로는 태근(太根), 세근(細根) 모두가 10~30cm에서 60~70% 이상 집중되었으며, 태근(太根)은 주로 0.9cm 이하였고, 세근(細根)은 대부분이 점재(点在)(+)하고 있었다.

• 한국환경복원기술학회지
• /
• 제6권3호
• /
• pp.69-78
• /
• 2003

The main purpose of this study was to verify the shore margin protection effect of the root system of Salix gracilistyla Miq. developed from direct sticking cuttings on wetland, focusing on the effect of the root system reducing soil particle dissociation rate in water. The soil dissociation rate was examined through slaking tests with cylindric pure soil column at maximum particle density and the same size column of root reinforced soil. The dry weight of remained soil was measured after 5, 10, 15, 30minutes and 1, 6, 12, 24, 48hours inundation. As results, the soil particles began to dissociate severely at 10 minutes and only 10% of soil particles were left after 25minutes inundation. The stable slope angle of pure soil was $36^{\circ}$after 24 hours. On the other hand, the columns of root reinforced soil were stable even after 24hours, being dissociated only 7.2% of soil particles. So, it was revealed that the root system was very effective materials protecting more than 80% of soil particle from dissociation in inundation.

• 한국정보통신학회논문지
• /
• 제10권7호
• /
• pp.1326-1331
• /
• 2006

일반적으로 용접 Root 캡은 여러 가지 용접 결함들 중에 용접 품질을 저하시키는 중요한 요인 중의 하나이다. Gas metal arc welding (GMAW)에서 root 갭은 용접 전류, 아크 전압, 용적률 등과 같은 여러 가지 용접 파라미터들에 영향을 미친다. 그러나 용접 공정의 비선형성 때문에 root 갭과 많은 용접 파라미터들 사이의 관계를 분석하기가 힘들다. 그리고 아크센서를 사용하였을 경우, 감지된 신호에 대한 신호처리가 어렵지만 가격이 저렴하고 자동화하기가 쉬우므로 현재의 산업공정에서 대부분 아크센서가 사용되고 있다. 지금까지 언급된 여러 가지 어려운 문제점과 아크센서의 특정 때문에 본 논문에서는 GMAW에서 root 갭을 검출할 수 있는 적당한 용접 파라미터들을 선정하고, root 캡과 선정된 파라미터들의 관계를 인식할 수 있는 신경회로망을 이용하여 root 갭 검출 시스템을 설계하였다. 또한, 용접 품질의 검사에 용접 비드형상이 중요한 요인이다. 따라서 본 논문에서는 신경회로망으로 용접 파라미터와 용접 비드형상과의 관계를 인식하여, 용접 품질을 추정하고 용접 파라미터들의 효과를 분석할 수 있는 용접 비드 형상의 실시간 모니터링 시스템을 제안하여 여러 실험 데이터들을 기반으로 한 시뮬레이션을 통해 제안된 시스템이 root 갭을 검출하고 또한 용접 비드 형상을 실시간으로 모니터링이 가능함 보여준다.

• 한국가시화정보학회지
• /
• 제14권1호
• /
• pp.40-45
• /
• 2016

Elimination of the smear layer and bacteria in the root canal is the most important in the endodontic treatment, and various irrigation devices have been developed. Nevertheless, it is hard to eliminate the smear layer and bacteria completely. In this paper, a micro bubble irrigation system has been developed for the root canal cleaning of tooth. Micro bubbles are generated when pressurized fluids passing through a porous material inside a hand-piece nozzle, and the bubbly flows excited by ultrasonic vibration are observed using a high-speed camera and a microscope. The results show that the diameter and number of bubbles increases with the applied pressure, and there found an optimum excitation frequency in order to minimize the bubble size. From in-vitro tests, it is also verified that the developed bubble irrigation system has the ability of antibacterial and infection removal. Thus, this biocompatible system would be well suited for root canal cleaning.