• 제목/요약/키워드: Normal Direction

검색결과 1,128건 처리시간 0.034초

일방향성 배열을 가진 Sic whisker에 의해 강화된 알루미나 복합체의 Whisker orientation 에 따른 마모마찰 특성 (Tribological Behavior of the Alumina Reinforced with Unidirectionally Oriented SiC whiskers depending on whisker orientation)

  • 간태석;한병동;임대순
    • 한국윤활학회:학술대회논문집
    • /
    • 한국윤활학회 1999년도 제29회 춘계학술대회
    • /
    • pp.220-224
    • /
    • 1999
  • Sliding wear test was employed to determine the effect of whisker content and orientation on the firiction and wear behavior of SiC whisker reinforced alumina. Composites containing unidirectionally oriented whiskers were prepared by a modified tape casting followed by lamination, binder removal and hot pressing in order to align the whiskers in the tape casting direction. Wear coefficients on three directions were measured; parallel and normal to the tape casting direction on the tape casting surface and normal to lamination direction on surfnce normal to the tape casting direction. In the effect of whisker orientation, the highest wear rate was obtained in the direction parallel tape casting direction and the lowest in the direction normal to lamination direction at all temperatures. Silicon oxide layer amoothing the surface was detected by energy dispersive X-ray analysis on the worn surface.

  • PDF

SCALED VISUAL CURVATURE AND VISUAL FRENET FRAME FOR SPACE CURVES

  • Jeon, Myungjin
    • 충청수학회지
    • /
    • 제34권1호
    • /
    • pp.37-53
    • /
    • 2021
  • In this paper we define scaled visual curvature and visual Frenet frame that can be visually accepted for discrete space curves. Scaled visual curvature is relatively simple compared to multi-scale visual curvature and easy to control the influence of noise. We adopt scaled minimizing directions of height functions on each neighborhood. Minimizing direction at a point of a curve is a direction that makes the point a local minimum. Minimizing direction can be given by a small noise around the point. To reduce this kind of influence of noise we exmine the direction whether it makes the point minimum in a neighborhood of some size. If this happens we call the direction scaled minimizing direction of C at p ∈ C in a neighborhood Br(p). Normal vector of a space curve is a second derivative of the curve but we characterize the normal vector of a curve by an integration of minimizing directions. Since integration is more robust to noise, we can find more robust definition of discrete normal vector, visual normal vector. On the other hand, the set of minimizing directions span the normal plane in the case of smooth curve. So we can find the tangent vector from minimizing directions. This lead to the definition of visual tangent vector which is orthogonal to the visual normal vector. By the cross product of visual tangent vector and visual normal vector, we can define visual binormal vector and form a Frenet frame. We examine these concepts to some discrete curve with noise and can see that the scaled visual curvature and visual Frenet frame approximate the original geometric invariants.

Evaluation of Dowel Bearing Strength of Structural Composite Lumber(SCL) on the Effect of Moisture Content

  • Oh, Sei Chang
    • Journal of the Korean Wood Science and Technology
    • /
    • 제31권3호
    • /
    • pp.61-69
    • /
    • 2003
  • This study investigated the effect of moisture content and loading direction on dowel bearing strength of two types of SCL. Dowel bearing tests of LVL and PSL were conducted with two different MC level, 7.5% and 19%, and two different oriention, L-direction(loading parallel to grain) and X-direction(loading perpendicular to grain). Most of specimens showed typical load-deformation curves and intersected 5% offset line. Failure modes were classified into two categories; spliting(for L-direction specimens) and peeling(for X-direction specimens). Dowel bearing strength generally decreased with increasing MC. The decreasing rate was more significant in X-directon. ESG also decreased with increasing MC, and the ratio of ESG of 7.5% versus 19% was about 1.47. Dowel bearing strength of LVL and PSL in L-direction was higher than that of X-direction. This results indicated that MC and loading orientation had a significant effect on dowel bearing strength of SCL. The average dowel bearing strength of LVL were higher than that of PSL in each loading direction. Two types of probability distribution model were chosen to quantify strength distribution, normal and 2-parameter weibull distribution. The two models showed good agreement with the data, especially in lower tail of the cumulative distribution. Normal and 2-parameter weibull distribution seemed to proper model of the dowel bearing strength for each MC levels.

THE ZEROS DISTRIBUTION OF SOLUTIONS OF HIGHER ORDER DIFFERENTIAL EQUATIONS IN AN ANGULAR DOMAIN

  • Huang, Zhibo;Chen, Zongxuan
    • 대한수학회보
    • /
    • 제47권3호
    • /
    • pp.443-454
    • /
    • 2010
  • In this paper, we investigate the zeros distribution and Borel direction for the solutions of linear homogeneous differential equation $f^{(n)}+A_{n-2}(z)f^{(n-2)}+{\cdots}+A_1(z)f'+A_0(z)f=0(n{\geq}2)$ in an angular domain. Especially, we establish a relation between a cluster ray of zeros and Borel direction.

충결하중의 방향에 따른 정전집진기 집진판의 진동 특성 연구 (A Study on the Vibration Characteristics by the Change of Impact Load Direction in the Collecting Plates of Electrostatic Precipitator)

  • 나종문;이기백;양장식
    • 소음진동
    • /
    • 제5권2호
    • /
    • pp.247-256
    • /
    • 1995
  • In this paper, double exposure holographic interferometry using ruby pulse laser is formed in order to investigate the propagation of transient waves. The vibration characteristics according to the change of impact load direction, i.e., impacted in the shear direction and in the normal direction are analyzed. It was observed that the macroscopic trends of transient wave generation and propagation in the assembly of precipitator plates were almost similar regardless of the change of impact load direction. But the propagation and mixing of transient wave was advanced relatively slowly when impacted in the normal direction.

  • PDF

초음파 모터용 람다형 다방향 변환자 (Multi-directionally Movable Lambda Shape Transducer for Ultrasonic Motor)

  • 도영수;남효덕;김영덕
    • 한국전기전자재료학회논문지
    • /
    • 제21권2호
    • /
    • pp.131-136
    • /
    • 2008
  • The transducer for multi-directionally movable ultrasonic motor having lambda shaped vibrators has been proposed and designed. The two branches cross at a right angle with each other at the tip. FEM analyses of lambda shaped transducer were carried out to find vibration modes for ultrasonic motor. The lambda shaped transducer has one symmetric mode and two anti-symmetric modes. The symmetric mode generates the normal direction motion of the tip. The lateral and vertical direction motion of the tip are excited by two anti-symmetric modes. The normal and lateral direction motions made an lateral elliptic trajectory. And the normal and vertical direction motions made an vertical elliptic trajectory normal to previous one. The transducer with 1 mm in thickness and 25 mm in length has been fabricated and evaluated. The resonance frequencies of the transducer was 32 kHz and 103 kHz. The tangential and vertical vibration displacement of the transducer having the lateral elliptic trajectory were $1.5{\mu}m\;and\;1.1{\mu}m$, respectively at the driving voltage of 100 Vpp and frequency of 32 kHz and 103 kHz. And the tangential and vertical vibration displacement of the transducer having the vertical elliptic trajectory were $0.4{\mu}m\;and\;0.2{\mu}m$, respectively at the same driving condition.

ON THE NORMALITY OF TRANSLATED FAMILIES OF TRANSCENDENTAL ENTIRE FUNCTIONS

  • KIM JEONG HEON;KWON KI HO;PARK SUK BONG
    • Journal of applied mathematics & informatics
    • /
    • 제17권1_2_3호
    • /
    • pp.573-583
    • /
    • 2005
  • For a certain set G in the complex plane, we construct a transcendental entire function f whose translated family ${f(2^{n}z)}$ is normal only at z in G and establish the relation between the normal family and the Julia direction of f(z).

Comparison of Fractional Anisotropy Values of Corticospinal Tract and Corpus Callosum between 6- and 25-Direction Diffusion Tensor Images in Normal Subjects

  • Lee, Jeong-Hyun;Lee, Sun-Young;Kim, Hyun-Jeong;Park, Choong-Gon;Lee, Deok-Hee;Lee, Ho-Kyu;Kim, Sang-Joon;Suh, Dae-Chul
    • 대한자기공명의과학회:학술대회논문집
    • /
    • 대한자기공명의과학회 2003년도 제8차 학술대회 초록집
    • /
    • pp.20-20
    • /
    • 2003
  • Purpose: To investigate the difference of fractional anisotropy (FA) values between 6- and 25-direction diffusion tensor images (DTI) in normal adult brain. Materials and Methods: DTI was peformed in 28 normal subjects (15 subjects with 6-direction, 13 subjects with 25-direction) in a 1.5 T MR system. DTI was done with SE-EPI sequence with TR/TE/NEX 10000/84/1, 5mm slice thickness and b=1000 s/mm2. FA values were measured from 8 different anatomical locations which included both cerebral peduncles, both posterior limbs of the internal capsules, both corona radiata, genu and splenium of the corpus callosum. Statistical difference of FA was tested between 6-and 25-direction DTI.

  • PDF

Anisotropic Phase Transitions of Hard-Spheres Confined in Hard Walls

  • 윤병집
    • Bulletin of the Korean Chemical Society
    • /
    • 제22권12호
    • /
    • pp.1375-1379
    • /
    • 2001
  • Monte Carlo simulations of hard-spheres confined in parallel hard walls have been carried out extensively at various densities and for various wall distances. The compressibility factors in the directions parallel and normal to the wall have been calculated from the radial free space distribution function (RFSDF) with the results showing that the compressibility factors normal to the wall are smaller than those in parallel direction and that a solid phase is formed in the direction normal to the wall while a fluid phase remains in the parallel direction. An order parameter is found to classify the phases whether a system (or a molecule) is in a fluid or a solid state. The compressibility factors of narrow wall are very small compared to those when the wall is put away. A plausible mechanism of the rise of sap in xylem vessel has been proposed.

혼합치열 및 영구치열기에서 mesh diagram을 이용한 3급 부정교합자 악안면구조의 위치변화에 관한 비교 연구 (A COMPARATIVE STUDY ON THE POSITIONAL CHANCES OF CRANIOFACIAL STRUCTURES BETWEEN MIXED AND PERMANENT DENTITION IN CLASS III MALOCCLUSION BY MESH DIAGRAM)

  • 이영미;김광원
    • 대한치과교정학회지
    • /
    • 제23권1호
    • /
    • pp.101-113
    • /
    • 1993
  • For the purpose of interpretation of positional changes of craniofacial structures in Class III malocclusion between mixed and permanent dentition, 73 normal samples and 103 Class III samples of mixed dentition and 125 normal samples and 168 Class III samples of permanent dentition were selected. Comparative cephalometric analysis was undertaken between them respectively by mesh diagram method to evaluate the positional changes of maxilla and mandible in anteroposterior direction and vertical direction and also the inclination changes of maxillary and mandibular incisors in labio-lingual direction. The following results were obtained : 1. The antero-posterior positional changes of the maxilla and mandible were posterior direction of maxilla and anterior direction of mandible. 2. The vertical positional changes of the maxilla and mandible were superior direction of both maxilla and mandible. 3. The labio-lingual inclination changes of the maxillary and mandibular incisors were lingual direction of both maxillary and mandibular incisors.

  • PDF