• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 춘계학술대회 논문집
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• pp.622-627
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• 2012

During helicopter rotor system development process, whirl tower test is conducted basically. For conducting whirl tower test during bearingless hub development process, design new blade or using existing blade with repair or remodeling. Because simple shape and efficient aerodynamic characteristic, BO-105 blade is used for hub system development widely. Originally BO-105 blade is used for hingeless hub, ho flap stiffness and lag stiffness on blade root area is relatively low. So applying BO-105 blade to bearingless hub whirl tower test, root area have to be reinforce. In this process, blade root area's section property will be changed. In this paper, suggest reinforcement method of BO-105 blade root area and study dynamic characteristic of bearingless rotor system with reinforcement BO-105 blade.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2000년도 춘계임시총회 및 학술발표대회
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• pp.38-44
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• 2000

To determine the optimum sowing date and nursery period in Alisma piantago in the southern area of Korea, Alisma plantago local cultivar was grown under three different sowing dates and nursery periods. The plant height, leaf width and leaf length at the area sown on the seedbed in June 30 and conducted the growing seedling in 30 days is 12.1cm, 2.5cm and 3.1cm respectively and it shows tess decrease than that of plant height, leaf width and leaf length with 12.3cm, 2.6cm and 3.2cm respectively which was sown on the seedbed in June 20 and carried out the growing seedling in 30 days, and it also shows less decrease than that of plant height, leaf width and leaf length with 15.2cm, 3.1cm and 5.2cm respectively at the area sown on the seedbed in July 10 and condected the growing seedling in the same date. The stem length, number of stems and diameter of root at the area sown on the seedbed in June 30 and conducted the growing seedling in 30 days is 31cm, 11 and 3.7cm respectively and it shows more increase than that of stem length, number of stem and diameter of and on the other hand shows tess decrease than that of stem length, number of stems and diameter of root with 30cm, 10cm, 35cm respectively which was sown on the seedbed in 30 days, and on the other hand shows less decrease than that of stem length, number of stems and diameter of root with 32cm,13cm,3.9cm respectively at the area sown on the seedbed in July 10 and conducted the growing seedling in the same date, The fresh yield of roots at the area sown on the seedbed in June 30 and conducted the growing seedling in 30 days is 431.4Kg/10a and it shows more increase of 26.9Kg than that of fresh yield of root with 410.59g110a which was sown on the seedbed in lune 20an4 carried out the growing seedling in 30 days, and it also shows more increase of 7Kg than that of fresh yield of root with 430.4Kg/10a at the area sown on the seedbed in July 10 and conducted the growing seedling in the same date. The dry yield of roots at the area on the seedbed in June 30 and conducted the growing seedling in 30 days is 351.9Kg110a which was sown on the seedbed in June 20 and carried out the growing seedling in 30 days, and it also shows more increase of 16.4Kg than that of dry yield of root with 335.4Kg110a at the area sown on the seedbed in July 10 and conducted the growing seedling in the same date. Therefore, the seedling period of proper seedbed for high yield bumper crop of Alisma plantago for exporting to Japan is June 30 and the number of days for seedling is 30 days.

• Journal of Periodontal and Implant Science
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• 제25권3호
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• pp.668-678
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• 1995

In order to evaluate the therapeutic effect of argon laser irradiation on hypersensitive root, 60 mandibular premolars that had been extracted due to periodontal disease were treated by thorough scaling, root planing and root conditioning with tetracycline HCI(100mg/ml, 5 min.) for induction of hypersensitive root. Within middle one third of root mesial surface(30) or distal surface(30) was randomly irradiated by 0.5W-, 0.75W- and 1.0W-power for 2 minutes argon laser(HGM Inc., USA) with or without topical application of 1.23% acidulated phosphate fluoride gel(Pascal, USA). After all teeth were maintained in 2% methylene blue solution for 48 hours and cross-sectioned through irradiated surface of dried roots, methylene blue stained area was compared between irradiated side and nonirradiated side. Following results were obtained : 1. Methylene blue stained area was significantly less in the laser irradiated group than control group(p<0.05). 2. There was no significant difference in methylene blue stained area between 0.5W-power and 0.75W-power group(p>0.1) and between 0.75W-power and 1.0W-power group(p>0.1), but there was significant difference between 0.5W-power and 1.0W-power group(p<0.05). 3. There was no significant difference in methylene blue stained area between two groups with and without topical application of 0.12% acidulated phosphate fluoride gel(p>0.1). The results suggest that argon laser irradiation on hypersensitive root may reduce the hypersensitivity by obstruction of dentinal tubules.

• Journal of Periodontal and Implant Science
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• 제30권2호
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• pp.429-442
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• 2000

Based on current evidence in the literature, it is known that endotoxin is a weakly adherent surface phenomenon and that power-driven instruments can be used to accomplish definitive root detoxification and maximal wound healing without overinstrumentation of root and without extensive cementum removal. And one of the newly developed curette tips used with low power of piezoelectric ultrasonic scaler, is effective to remove calculus and not to remove the excessive cementum. The purpose of this study is therefore, to assess the influence of ultrasonic power and various working parameters on root substitute removal when instrumentation is performed with the curette tip on piezoelectric ultrasonic scaler. This study assessed defect depth, width and area resulting from instrumentation using a piezoelectric ultrasonic scaler with a curette type tip in vitro to acrylic resin block as a root substitute. The working parameters was standardized by the sledge device which controls lateral force(0.5 N, 1 N, 2 N) and instrumentation time(5 sec, 10 sec, 20 sec) and power setting was adjusted 0,2,4,8 in P mode. Power setting had the greatest influence on defect depth compared to lateral force and instrumentation time(standardized regression parameter estimates${\pm}$standard error, $0.37{\pm}0.02$, $0.19{\pm}0.02$, $0.07{\pm}0.02$). The effects on defect area also greatest for power setting($0.57{\pm}0.03$) compared to lateral force and instrumentation time($0.33{\pm}0.03$, $0.12{\pm}0.03$). The effect of the power setting on the defect width($0.15{\pm}0.01$) is not so great as defect depth or defect area compared to lateral force($0.12{\pm}0.01$) and effect of instrumentation time is minimal($0.02{\pm}0.01$). It could be concluded that the power setting has the greatest influence on the defect depth and area in curette type tip with low power of piezoelectric ultrasonic device. Many parameters can be adjusted in various situation in clinical use of piezoelectric ultrasonic scaler but the power setting is the first parameter to be adjusted.

• 대한치과보철학회지
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• 제35권3호
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• pp.486-503
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• 1997

The purpose of this study was to evaluate the stress patterns developed in abutment and residual ridge according to removable denture design in case of remaining mandibular canines. The removable denture designs in this study were as foolows : 1. Removable partial denture with non-splinted abutment 2. Removable partial denture with splinted abutment 3. Overdenture with telescopic crown 4. Overdenture with O-Ring attachment 5. Overdenture with combination bar attachment Photoelastic stress analysis was used to record the isochromatic fringe patterns and to calculate principal stress components at measuring points. The results were as follows : 1. In case of removable partial denture with non-splinted abutment, stress of root area at the loaded side was the largest. No significant differences in stress of root area were observed between loaded side and unloaded side. 2. No significant differences in stress of residual ridge at the loaded side were observed between removable partial denture with splinted abutment and removable partial denture with non-splinted abutment. 3. In case of combination bar attachment retained overdenture, stress of root area was the largest and in case of telescopic crown retained overdenture, stress of root area was the lowest. 4. In case of attachment retained overdenture, stress of residual ridge was lower but stress of root area was larger than in case of removable partial denture.

• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2001년도 춘계학술대회
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• pp.243-244
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• 2001

Root resorption is conventionally divided into internal and external varieties. Internal resorption occurs where there is loss of the internal wall of the root canal. and is usually associated with a localized area of necrotic pulp(Trope '||'&'||' Chivian 1984). External resorption occurs where there is loss of the external surface of the root and the resorption may be either transient or progressive(Tronstad 1988). External inflammatory resorption usually occurs following damage to the periodontal ligament or where there is communication between the periodontal ligament and a necrotic pulp. via open dentinal tubules or accessory canals. This type of resorption is usually progressive until root canal treatment is instituted (Barclay 1993).

• 한국환경복원기술학회지
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• 제14권4호
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• pp.41-54
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• 2011

Tree roots can enhance soil shear strength and slope stability. However, there has been a limited study about root reinforcement of major tree species in Korea because of some experimental difficulties. Thus, this study was conducted to analyze the performance of Japanese larch (Larix kaempferi) and Korean pine (Pinus koraiensis) which are two common plantation species in Korea. Profile wall method was used to measure the spatial distribution of root system and its diameter within 15 soil walls of Japanese larch stand and 13 soil walls of Korean pine stand in Taehwa University Forest, Seoul National University, Korea. Root tensile properties of each species were assessed in the laboratory, and root reinforcements were estimated by Wu model. The study observed that the number and cross-sectional area (CSA) of root in both species could tend to decrease with soil depth. Especially, CSA were well-fitted to exponential functions of soil depth. Mean root area ratios (RAR) were 0.03% and 0.10% for Japanese larch and Korean pine, respectively. Estimated root reinforcement from Wu model were, on the average, 4.04 kPa for Japanese larch and 12.26 kPa for Korean pine. Overall, it was concluded that root reinforcement increased the factor of safety (Fs) of slope for small-scale landslide as the result of two-dimensional (2-D) infinite slope stability analysis considering vegetation effects.

• 생물환경조절학회지
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• 제32권3호
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• pp.205-209
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• 2023

기계적 자극은 식물체의 형태적 변화를 유도하는 것으로 알려져 있다. 본 연구에서는 기계적 자극을 적용한 토마토의 육묘기 동안의 생육 변화를 확인하기 위해 수행되었다. 브러싱 처리가 기계적 자극으로 이용되었으며, 아크릴이 부착된 이송장치를 이용하여 2시간 간격으로 파종 후 10일 이후부터 처리를 진행하였다. 브러싱 처리 동안 생육 변화를 확인하기 위해 3일 간격으로 생육을 조사하였다. 초장과 엽면적은 브러싱 처리에서 대조구에 비해 감소하는 결과를 보였으며 지상부의 생체중과 건물중은 대조구와 유사한 값을 보였다. 총 근장과 지하부 표면적은 브러싱 처리에서 대조구에 비해 증가하였으며, 지하부 부피는 대조구와 브러싱 처리가 유사한 값을 보였다. 결론적으로 토마토 공정묘에 브러싱 처리는 지상부의 생육 감소를 유도하였으며 지하부의 형태적 발달을 증가시키는 것으로 판단된다.

• Journal of Ginseng Research
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• 제20권1호
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• pp.78-82
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• 1996

In order to clarify effect of transplanting angle of seedling on shape and growth of ginseng root, ginseng of seedlings were transplanted with $60^{\circ}$ and $90^{\circ}$ respectively, and the root characters of 2-, 4- and 6-year-old ginseng were investigated. The length of main root with 45$^{\circ}$was above 7 cm (standard) but that of $60^{\circ}$ and $60^{\circ}$ was below 7 cm (standard). Number of good lateral root was above 2.3 ea for $45^{\circ}$, 0~$30^{\circ}$, but below 2.3 ea per plant for 60~$90^{\circ}$ respectively. Root fresh weight with $0^{\circ}$, $30^{\circ}$, $45^{\circ}$ was heavier than that with $60^{\circ}$ and $90^{\circ}$. Root disease infection rate was highest with $0^{\circ}$. There were, no significant difference in stem length, stem diameter, leaf area, comber of palmate leaves and leaflets per plant, ratio of missing plant, root diameter in 2-, 4- and 6-year-old ginseng.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제4권1호
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• pp.77-85
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• 1997

In this work we will show that, in the sense of the Maximum overestimation factor, the absolute root bound functional derived from the new formula for the divided difference is better than the other known results in this area.