• 제목/요약/키워드: Root shape

검색결과 471건 처리시간 0.024초

CBCT와 치과용 현미경을 이용한 C형 근관을 가지는 하악 제1소구치의 근관치료 (Endodontic management of mandibular first premolar with C-shaped canals by using cone-beam computed tomography and dental operating microscope)

  • 장훈상;김민정;이석련;홍성옥
    • 구강회복응용과학지
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    • 제30권4호
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    • pp.324-328
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    • 2014
  • 한국인에서는 하악 소구치의 변이가 매우 드물게 나타나며, 변이는 하악 소구치 근관치료시 성형과 세정으로 자극원의 제거를 어렵게 하여 근관치료의 실패를 야기할 수 있다. 본 증례에서는 C형의 드문 근관 형태를 가지는 하악 제1소구치를 CBCT를 촬영하여 복잡한 치아의 내부 형태를 확인한 후, 치과용 현미경을 사용해 확대된 시야와 개선된 조명하에서 성공적으로 근관치료 하였다.

십자형 필릿 용접부에서의 피로파괴 형상과 특성 (Patterns and Characteristics of Fatigue Failure in Cruciform Fillet Weld Joint)

  • 이용복;정준기;박상흡
    • Journal of Welding and Joining
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    • 제29권4호
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    • pp.67-72
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    • 2011
  • The proportion of the welding in the production process of machinery, buildings and marine structures is increasing and the joining are mainly conducted by butt and fillet weld. In the case of fillet weld, the shape of structures is complicated depending on the constraint on the geometry of the structures, therefore, the full penetration is mostly difficult. Accordingly, it is necessary to establish safe and economical criteria of design of the structures through the strength based on the penetration state of the fillet weld. Patterns of fatigue failure in cruciform fillet weld jont appear in the form of the root, toe and mixed failure. In the case of toe and mixed failure, the fatigue strength is higher than root failure. Therefore, we have to make the enough depth of penetration or perform the welding work through improving the fatigue strength of cruciform joints in welded structures. So it is necessary to optimize the penetrated depth in the range of the possible mixed failure and find the way in the cost-effective design to lessen the amount of the welding work.

Effect of Capsaicin on Delayed Rectifier $K^+$ Current in Adult Rat Dorsal Root Ganglion Neurons

  • Hahn, Jung-Hyun;Chung, Sung-Kwon;Bang, Hyo-Weon
    • The Korean Journal of Physiology and Pharmacology
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    • 제4권1호
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    • pp.9-14
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    • 2000
  • $K^+$ currents play multiple roles in the excitability of dorsal root ganglion (DRG) neurons. Influences on these currents change the shape of the action potential, its firing threshold and the resting membrane potential. In this study, whole cell configuration of patch clamp technique had been applied to record the blocking effect of capsaicin, a lipophilic alkaloid, on the delayed rectifier $K^+$ current in cultured small diameter DRG neurons of adult rat. Capsaicin reduced the amplitude of $K^+$ current in dose dependent manner, and the concentration-dependence curve was well described by the Hill equation with $K_D$ value of $19.1{\mu}M.$ The blocking effect of capsaicin was reversible. Capsaicin $(10 {\mu}M)$ shifted the steady-state inactivation curve in the hyperpolarizing direction by about 15 mV and increased the rate of inactivation. The voltage dependence of activation was not affected by capsaicin. These multiple effects of capsaicin may suggest that capsaicin bind to the region of $K^+$ channel, participating in inactivation process.

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Phytophthora nicotianae(Breda de Haan)에 의한 카네이션 역병 (Root Rot of Carnation Caused by Phytophthora nicotianae)

  • 류경열;진경식;이영희
    • 한국식물병리학회지
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    • 제14권2호
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    • pp.115-119
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    • 1998
  • Root rot of carnation caused by isolates of Phytophthora was found at Kongju, 1996. Infected plants appeared symptoms of wilting, brown discoloration on collar area and consequently led to death. The causal pathogen was identified as Phytophthora nicotianae based on morphological, cultural and physiological characteristics. Mycelium was grown to rosette colony pattern on corn meal agar and the growth was 10.2 mm/day on 10% clarified V8 medium at $25^{\circ}C$. Swelling with radiating hyphae was formed in water and on agar within 7 days. Chlamydospores were abundantly produced on agar within 7 days. Sporangium was prominent papillate, 2~3 apex, 1.2 : 1 l/b ratio, lateral attacment on sporangiospore and was rarely produced on solid media but produced in water. The shape of sporangium was spherical or ovoid, and the size was 34~73$\times$32~60 (av. 33$\times$66.5) ${\mu}{\textrm}{m}$ in dimension. The isolates were heterothallic, and mating type A2. Oogonium was spherical, ovoid, 26~36 (av. 36 ${\mu}{\textrm}{m}$) in diameter, and antheridium was amphygynious to oogonia. The fungus was able to grow 10~35$^{\circ}C$, and optimal temperature was 27$^{\circ}C$.

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Nematicidal activity of Glycyrrhiza uralensis Fisch. root extracts on Meloidogyne incognita eggs and juveniles

  • Dang-Minh-Chanh Nguyen;Thi-Hoan Luong;Van-Viet Nguyen;Woo-Jin Jung
    • Journal of Applied Biological Chemistry
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    • 제66권
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    • pp.388-393
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    • 2023
  • This study evaluated the in vitro nematicidal activity of Glycyrrhiza uralensis root extracts (GuRE) on Meloidogyne incognita eggs and juveniles. The results showed that treatment of M. incognita eggs with 2.0 mg/mL GuRE for 5 and 10 d resulted in 64.0 and 68.1% hatch inhibition, respectively. Furthermore, the relative mortality of J2 was 96.2% after treatment with 2.0 mg/mL GuRE for 48 h. Changes in the shape of the eggs and juveniles were determined after incubation with 2.0 mg/mL GuRE for 5 d and 48 h, respectively. These preliminary results suggest that GuRE can be used as an environment-friendly bio-nematicide to control root-knot nematodes. In the future, in vivo assays should be conducted using GuRE to ascertain its potential for widespread application as a nematicide.

i-PGS 기반 선회베어링의 접촉피로강도 설계 (Contact Fatigue Strength Design of a Slewing Bearing Based on i-PGS)

  • 권순만;신흥철
    • 한국생산제조학회지
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    • 제25권1호
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    • pp.21-29
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    • 2016
  • To overcome the large ring gear manufacturing problems seen in slewing bearings and girth gears, pin gear drive units have been developed. Among them, a novel slewing bearing with an internal pinwheel gear set (i-PGS) is introduced in this paper. First, we consider the exact cam pinion profile of i-PGS with the introduction of a profile shift coefficient. Furthermore, a new root relief profile modification for the i-PGS cam pinion is presented. Then, the contact stresses are investigated to determine the characteristics of the surface fatigue by varying the shape design parameters. The results show that the contact stresses of i-PGS can be reduced significantly by increasing the profile shift coefficient. In addition, the contact ratio, a measure of teeth overlapping action, decreases with the decrease of the allowable pressure angle.

풍력블레이드용 에어포일세트의 설계 및 해석 (Design and analysis fo wind turbine airfoils)

  • 신형기;김석우
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2007년도 춘계학술대회
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    • pp.362-365
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    • 2007
  • In wind turbine blades, airfoils are required to have different spec when compared with airplane airfoil. Airfoils for wind turbine blade must have a high lift-to-drag ratio, moderate to high lift and especially low roughness sensitivity. Also an operation Re. No.s are lower than conventional airplane airfoils. At mid-span and inboard region, structural problems have to be considered. Especially, for stall regulated type, moderate stall behavior is essential part of design. For these reasons, airfoil design for HAWT blade is essential part of blade design. In this paper, root airfoil and tip airfoil are discussed. For a root region, 24% thickness airfoil is designed and for a top region, 12% thickness ratio is done. A inverse design method and panel method are used for rapid airfoil design. In this paper, a design method, features of airfoil shape and characteristics are discussed.

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Parameter Estimations in the Complementary Weibull Reliability Model

  • Sarhan Ammar M.;El-Gohary Awad
    • International Journal of Reliability and Applications
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    • 제6권1호
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    • pp.41-51
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    • 2005
  • The Bayes estimators of the parameters included in the complementary Weibull reliability model are obtained. In the process of deriving Bayes estimators, the scale and shape parameters of the complementary Weibull distribution are considered to be independent random variables having prior exponential distributions. The maximum likelihood estimators of the desired parameters are derived. Further, the least square estimators are obtained in closed forms. Simulation study is made using Monte Carlo method to make a comparison among the obtained estimators. The comparison is made by computing the root mean squared errors associated to each point estimation. Based on the numerical study, the Bayes procedure seems better than the maximum likelihood and least square procedures in the sense of having smaller root mean squared errors.

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브러시 디버링 연삭 시스템 공정 최적화에 대한 연구 (A Study on the Process Optimization of Brush Deburring Grinding System)

  • 신관수
    • 한국생산제조학회지
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    • 제21권3호
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    • pp.394-400
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    • 2012
  • Due to the increasing demand for carious methodologies, the quality improvement of products were introduced. A brush, the most frequently used type of grinding process, is one of the deburring. In order to produce consistent burr shape, various machining conditions have been combined and applied to disk grinding process. By tool dynamometer, acoustic emission sensor and acceleration sensor depend on changes in processing conditions(depth of engagement, cutting speed, workpiece position, workpiece orientation, cutting time) signals were obtained for brush deburring grinding system. Root mean square obtained by processing the signal processing conditions by analyzing the characteristics of deburring is to derive the optimum conditions.

연근 전분의 이화학적 특성 (Physicochemical Properties of Lotus root (Nelunbo nucifera G.) Starch)

  • 양희천;김용휘;이태규;차연수
    • Applied Biological Chemistry
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    • 제28권4호
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    • pp.239-244
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    • 1985
  • Physicochcmical properties of the Lotus root starch wert investigated. The shape of starch granules was elliptical with the average size of $20{\sim}35{\mu}$. Starch showed B-type X-ray pattern. The content of amylose was 22.1%. The blue value for starch and amylose were 0.280 and 0.692, respectively. The alkali number was 4.74. By X-ray diffraction examination, gelatinization began at $55^{\circ}C{\sim}60^{\circ}C$ and almost completed at $65^{\circ}C{\sim}70^{\circ}C$.

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