• 제목/요약/키워드: Angle of plate

검색결과 1,134건 처리시간 0.024초

Displacement pattern of the anterior segment using antero-posterior lingual retractor combined with a palatal plate

  • Seo, Kyung-Won;Kwon, Soon-Yong;Kim, Kyung A;Park, Ki-Ho;Kim, Seong-Hun;Ahn, Hyo-Won;Nelson, Gerald
    • 대한치과교정학회지
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    • 제45권6호
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    • pp.289-298
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    • 2015
  • Objective: To evaluate and compare the effects of two appliances on the en masse retraction of the anterior teeth anchored by temporary skeletal anchorage devices (TSADs). Methods: The sample comprised 46 nongrowing hyperdivergent adult patients who planned to undergo upper first premolar extraction using lingual retractors. They were divided into three groups, based on the lingual appliance used: the C-lingual retractor (CLR) group (group 1, n = 16) and two antero-posterior lingual retractor (APLR) groups (n = 30, groups 2 and 3). The APLR group was divided by the posterior tube angulation; posterior tube parallel to the occlusal plane (group 2, n = 15) and distally tipped tube (group 3, n = 15). A retrospective clinical investigation of the skeletal, dental, and soft tissue relationships was performed using lateral cephalometric radiographs obtained pretreatment and post en masse retraction of the anterior teeth. Results: All groups achieved significant incisor and canine retraction. The upper posterior teeth did not drift significantly during the retraction period. The APLR group had less angulation change in the anterior dentition, compared to the CLR group. By changing the tube angulation in the APLR, the intrusive force significantly increased in the distally tipped tube of group 3 patients and remarkably reduced the occlusal plane angle. Conclusions: Compared to the CLR, the APLR provides better anterior torque control and canine tipping while achieving bodily translation. Furthermore, changing the tube angulation will affect the amount of incisor intrusion, even in patients with similar palatal vault depth, without the need for additional TSADs.

Effect of RBS on seismic performance of prefabricated steel-concrete composite joints

  • Zhen Zhu;Haitao Song;Mingchi Fan;Hao Yu;Chenglong Wu;Chunying Zheng;Haiyang Duan;Lei Wang
    • Steel and Composite Structures
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    • 제52권4호
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    • pp.405-418
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    • 2024
  • To study the influence of different reduced beam section (RBS) on the mechanical performance of modular boltedwelded hybrid connection joints (MHCJs), this article uses ABAQUS to establish and verify the finite element model (FEM) of the test specimens on the basis of quasi-static test research. Based on, 14 joint models featuring different RBS are devised to evaluate their influence on seismic behavior, such as joint failure mode, bending moment (M)-rotation angle (θ) curve, ductility, and energy consumption. The results indicate that when the flange and web are individually weakened, they alleviate to some extent the concentrated stress of the core module (CM) and column end steel skeleton in the joint core area, but both increase the stress on the flange connecting plate (FCP). At the same time, the impact of both on seismic performance such as bearing capacity, stiffness, and energy consumption is relatively small. When simultaneously weakening the flange and web of the steel beam, forming plastic hinges at the weakened position of the beam end, significantly alleviated the stress concentration of the CM and the damage at the FCP, improving the overall deformation and energy consumption capacity of joints. But as the weakening size of the web increases, the overall bearing capacity of the joint shows a decreasing trend.

라플라스 모세관이론과 수학물리학의 태동 (Theory of Capillarity of Laplace and birth of Mathematical physics)

  • 이호중
    • 한국수학사학회지
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    • 제21권3호
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    • pp.1-30
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    • 2008
  • 뉴턴의 중력이론의 성공은 수학물리학을 태동시키는 바, 최초로 19세기 초의 분자력의 모델성립에 중요한 요소로 등장하였다. 라플라스는 여기서 회전타원체의 작용이라는 모델을 이용하였고 회전타원체의 작용은 이계편미분방정식으로 표현이 되었다. 이것을 풀어서 유체를 담은 용기의 기하학적 모습과 와 유체와 고체의 접촉각에 대응시켰다. 알 수 없는 분자간거리는 추상적이고 미지의 힘 함수 $\varphi(f)$를 써서 표현하여, 분자 작용반경이라는 개념을 도입하여 이론적인 포텐셜 함수의 이론적인 토대를 구축하였다. 뉴턴의 중력이론은 라플라스이론에서 완성을 이루었고, 이후 분자력의 모델로서 작용을 하였다. 라플라스-영의 모세관이론은 수학적으로는 극소 곡면론에서 물리학적으로는 표면장력현상으로 설명이 된다.

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The Experimental Investigations of the Big Size Holographic Screen in the Autostereoscopic Displays

  • Son, J. Y.;Choi, Y. J.;Bahn, J. E.;Bobrinev, V.-I.
    • Journal of the Optical Society of Korea
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    • 제5권2호
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    • pp.55-59
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    • 2001
  • Results of an experimental study of possible ways to extend the capabilities of a big size transmission type holographic screen are presented. Different approaches to the problem of making a big size screen have been considered and tested experimentally. Up to 60$\times$80 $\textrm{cm}^2$ screens have been recorded on a single photographic plate VRP-M. By attaching a mirror behind the screen, the reflection mode of operation has been obtained. In this arrangement some additional peculiarities appear in the screen, which can be used to extend the screen capabilities. The first possibility is to increase the screen size by mosaicking the subscreens in the reflection mode of operation. Screens of 120$\times$80 $\textrm{cm}^2$ and 180$\times$40 $\textrm{cm}^2$ have been obtained by proper alignment of 60$\times$40 $\textrm{cm}^2$ subscreens. The second possibility is to move the viewing Bone by rotation of the screen together with the mirror and thereby realize by the eye-tracking capability. Methods of increasing vertical size of the viewing zone have been considered. Along with the multi-exposure method, which was considered in previous papers, addition of the vertical diffuser with the optimized scattering angle has been tested experimentally. The vertical size of the viewing zone has been increased by up to 10-15 cm. Another method consists of usage of a diffraction grating with vertical dispersion to solve the same problem.

Experimental and numerical investigation on the seismic behavior of the sector lead rubber damper

  • Xin Xu;Yun Zhou;Zhang Yan Chen;Song Wang;Ke Jiang
    • Earthquakes and Structures
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    • 제26권3호
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    • pp.203-218
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    • 2024
  • Beam-column joints in the frame structure are at high risk of brittle shear failure which would lead to significant residual deformation and even the collapse of the structure during an earthquake. In order to improve the damage issue and enhance the recoverability of the beam-column joints, a sector lead rubber damper (SLRD) has been developed. The SLRD can increase the bearing capacity and energy dissipation capacity, and also demonstrating recoverability of seismic performance following cyclic loading. In this paper, the hysteretic behavior of SLRD was experimentally investigated in terms of the regular hysteretic behavior, large deformation behavior and fatigue behavior. Furthermore, a parametric analysis was performed to study the influence of the primary design parameters on the hysteretic behavior of SLRD. The results show that SLRD resist the exerted loading through the shear capacity of both rubber parts coupled with the lead cores in the pre-yielding stage of lead cores. In the post-yielding phase, it is only the rubber parts of the SLRD that provide the shear capacity while the lead cores primarily dissipate the energy through shear deformation. The SLRD possesses a robust capacity for large deformation and can sustain hysteretic behavior when subjected to a loading rotation angle of 1/7 (equivalent to 200% shear strain of the rubber component). Furthermore, it demonstrates excellent fatigue resistance, with a degradation of critical behavior indices by no more than 15% in comparison to initial values even after 30 cycles. As for the designing practice of SLRD, it is recommended to adopt the double lead core scheme, along with a rubber material having the lowest possible shear modulus while meeting the desired bearing capacity and a thickness ratio of 0.4 to 0.5 for the thin steel plate.

군집분석을 통한 한국인 성인 골격성 제 II급 부정교합의 아분류 (Subclassification of Skeletal Class II Malocclusion of Korean Adults Using Cluster Analysis)

  • 안광석;백형선;김경호;김백일;이기준
    • 대한구순구개열학회지
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    • 제14권1_2호
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    • pp.1-18
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    • 2011
  • Skeletal malocclusion is the result of abnormal dimension and alignment of each skeletal component. Understanding on these mechanisms may help to elucidate the etiology of skeletal malocclusion and to establish population-oriented treatment plans. Attempts to subdivide the Angle's classification have been performed for Class III malocclusion, while few studies have been conducted for Class II malocclusion despite recent growing interests in Class II malocclusion. 200 adults (88 male, 112 female) with skeletal Class II malocclusion were collected and subdivided using cluster analysis, using the measurements representing the dimension and the alignment of each facial skeletal component. The properties of each cluster was grouped within the subjects and a comparison between the subjects and the control group (38 male, 35 female) with normal occlusion was performed. Six clusters were finally recognized in each male and female groups. The clusters in both genders were mainly characterized by the cranial base alignment, dimension of the posterior cranial base, dimension of the mandibular ramus and the degree of mandibular rotation. The results implicate that active treatment of mandible rather than the nasomaxillary complex may be primarily considered for the correction of Korean Class II skeletal pattern.

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Correction of Problematic Hypospadias with Dartos Fascia-Reinforced Flap and Slanted Incision of Fistula

  • Choi, Dong Sik;Lee, Jeong Woo;Yang, Jung Dug;Chung, Ho Yun;Cho, Byung Chae;Byun, Jin Suk;Choi, Kang Young
    • Archives of Plastic Surgery
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    • 제40권6호
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    • pp.766-772
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    • 2013
  • Background Hypospadias is the most common congenital malformation of the male urinary tract, wherein the urethral opening is located proximal to the normal site. Tubularized incised-plate urethroplasty reconstruction, and its efficacy, remains controversial due to the high recurrence rate. This study aimed to evaluate the results of dartos fascia-reinforced flap surgery in hypospadias patients with previous operative complications. Methods Nine patients (mean age, 12 years) who had previous one- or two-stage repair with TIP urethroplasty and suffered from urethrocutaneous fistulas or fissures as complications, underwent dartos fascia-reinforced flap surgery in our clinic between January 2010 and December 2012. The mean postoperative follow-up period was 6 months. Results Among the 9 patients, 7 had complete correction. In all the patients, the maximum uroflow angle was > $45^{\circ}$. No patient complained of an unnatural urinating position. The patients and parents gave very high satisfaction scores (4.7 points) with regard to the appearance of the outer genitalia. Conclusion The dartos fascia-reinforced flap could be a useful and reliable option for complications of hypospadias repair or fissure with the prepuce preserved, given that histological aspects vary and that the possibility of recurrence in the glanular region is high.

Optimization of Screw Pumping System (SPS) for Mass Production of Entrapped Bifidus

  • Ryu, Ji-Sung;Lee, Yoon-Jong;Choi, Soo-Im;Lee, Jae-Won;Heo, Tae-Ryeon
    • Food Science and Biotechnology
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    • 제14권5호
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    • pp.566-571
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    • 2005
  • Process of screw-pumping system (SPS) was optimized for mass production of encapsulated bifidus. SPS entrapment device was composed of feeding component, with optimized nozzle size and length of 18G (0.91 cm) and 4 mm, respectively, screw pump, and 37-multi-nozzle. Screw component had five wing turns [radius (r)=26 to 15 mm] from top to bottom of axis at 78-degree angle from middle of the screw, and two wings were positioned at screw edge to push materials toward nozzle. For nozzle component, 37 nozzles were attached to 20-mm round plate. Air compressor was attached to SPS to increase productivity of encapsulated bifidus. This system could be operated with highly viscous (more than 300 cp) materials, and productivity was higher than $1128\;{\pm}\;30\;beads/min$. Viability of encapsulated bifidus was $5.45\;{\times}\;10^8\;cfu$/bead, which is superior to that of encapsulated bifidus produced by other methods ($2.51{\times}10^8\;cfu$/bead). Average diameter of produced beads was $2.048\;{\pm}\;0.003\;mm$. Survival rate of SPS-produced encapsulated bifidus was 90% for Simulator of the Human Intestinal Microbial Ecosystem test and 88% in fermented milk (for 14 days). These results show SPS is effective for use in development of economical system for mass production of viable encapsulated bifidus.

전산화단층사진을 이용한 하악지구조분석 (A COMPUTERIZED TOMOGRAPHIC STUDY ON THE STRUCTURE OF THE MANDIBULAR RAMUS)

  • 김평수;안융;진우정;고광준
    • Maxillofacial Plastic and Reconstructive Surgery
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    • 제21권4호
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    • pp.345-352
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    • 1999
  • This study was conducted for the purpose of suggestion of the new technique of sagittal split ramus osteotomy pararell to the true sagittal plane. This pararellism is the important concept of the sagittal split ramus osteotomy to reduce the condylar sagging including mandibular hypomobility, temporomandibular disorder, occlusal relapse and other complications. We used 26 adult dry manibles(52 rami), and obtained the computed tomographs through the sagittal, horizontal and coronal sections. The results were obtained as follows. 1. On sagittal section, mean area of S1 was $8.63{\pm}2.10cm^2$, S2 was $8.93{\pm}1.94cm^2$, S3 was $9.49{\pm}2.15cm^2$, S6 was $10.72{\pm}2.22cm^2$. The wider area of sagittal section, the more lateral section, But, no significant differency between the areas of the sagittal sections(P>0.05). 2. On horizontal section, The distance between the inferior alveolar canal and the lateral cortical plate of the mandibular ramus were $6.73{\pm}1.24mm$ minum, $7.70{\pm}1.44mm$ maximum. 3. On coronal section, Outer mandibular angle were $4.84{\pm}2.37^{\circ}$ right side, $4.93{\pm}2.12^{\circ}$ left side. 4. The design of the ideal true sagittal split ramus osteotomy is that posterior border of osteotomy must be limited vertically, at the right posterior point of lingula mandibularis and anterior of osteotomy must be extended to mandibular body, anteroinferiorly.

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해성점토지반에 관입된 앵커 및 닻줄의 변형해석 (Anchor and Mooring Line Analysis in Cohesive Seafloor)

  • 한희수;전성곤;장동훈;장서용
    • 한국지반공학회논문집
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    • 제22권3호
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    • pp.37-43
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    • 2006
  • 이 연구는 선박을 정착하기 위하여, 해성점토에 관입된 앵커 및 닻줄의 변형, 인장력 및 지반거동을 해석할 수 있는 방법에 대한 연구로써, 앵커와 닻줄을 multi-segment로 나누어, 일차원 유한 요소 해석을 하였다. 각 element와 지반거동에 대한 힘과 모멘트의 평형조건을 만족시키면서, 앵커와 닻줄의 변형과 인장력을 해석하는 방법으로, 앵커 및 선박 상판에서 구할 수 있는 특정경계조건을 구한 후, 지속적인 반복작업을 이용하여 각 element의 변형과 인장력을 구하는 방법을 채택하였다. 이러한 연구결과는 앵커 및 닻줄이 사용된 해양구조물의 설계 및 시공에 반영될 수 있으며, 이 연구의 예측결과는 실제 현장 건ta와 비교 분석되었으며, 비교를 위한 항목으로는 anchor의 지지력, 닻줄길이, 선박에 연결된 닻줄의 각도 및 인장력 등이 사용되었다. 각 항목의 비교결과, 실제 현장 data와 상당히 일치하여, 이 방법으로 지반 및 선체의 거동을 예측할 수 있다는 것이 증명되었다.