• 제목/요약/키워드: cross-variation

검색결과 948건 처리시간 0.027초

진동저감을 위한 HDD용 Disk Clamp의 최적설계 (Optimal Design of Disk clamp to Reduce RRO in a Hard Disk Drive)

  • 이행수;고정석;황태연;정우철
    • 한국소음진동공학회:학술대회논문집
    • /
    • 한국소음진동공학회 2002년도 춘계학술대회논문집
    • /
    • pp.539-542
    • /
    • 2002
  • The role of disk clamp is to fasten disks to motor and to prevent the slip of disks during operation. This paper examined the effects of the design parameters of disk clamp - thickness, contact radius and cross-sectional shape -on the clamping force and circumferential stress distribution of disk. The large stress variation in circumferential direction results in large disk waveness and will increase repeatable run-out (RRO) finally. The disk clamp-disk-disk spacer system is modeled and the FE analysis is performed by ANSYS. The disk clamp with large contact radius shows more uniform stress distribution than the one with small contact radius and the stiffness variation around circumferential direct ion or the addition of the bending sect ion can make stress distribution uniform.

  • PDF

반용융 알루미늄 합금의 재가열 및 Thixoforging 부품의 기계적 성질 (Reheating of Semi-Solid Aluminum Alloys and Mechanical Properties of Thixoforged Product)

  • 정홍규;강충길
    • 소성∙가공
    • /
    • 제8권5호
    • /
    • pp.437-448
    • /
    • 1999
  • The reheating of the billet in the semi-solid state as quickly and homogeneously as possible is one of the most imposrtant parts. To obtain a fine globular microstructure in cross section of billet, the optimal design of the induction coil for variation of alloys and specimen sizes is necessary. For the thixo-forging process the construction of the reheating data base is very important, because the reheating conditions are different for variation of SSM and billet sizes. So in this study, the optimal coil design of A356 (ALTHIX) and Aι2024 with d×ι=60×90 (mm) to obtain the globular microstructure is theoretically proposed. The suitability of an optimal coil design will be demonstrated by reheating experiments. Finally, the thixoformability of an arbitrarily shaped product is evaluated by its forming variables. The defects and mechanical properties are also investigated.

  • PDF

Cone beam CT findings of retromolar canals: Report of cases and literature review

  • Han, Sang-Sun;Park, Chang-Seo
    • Imaging Science in Dentistry
    • /
    • 제43권4호
    • /
    • pp.309-312
    • /
    • 2013
  • A retromolar canal is an anatomical variation in the mandible. As it includes the neurovascular bundle, local anesthetic insufficiency can occur, and an injury of the retromolar canal during dental surgery in the mandible may result in excessive bleeding, paresthesia, and traumatic neuroma. Using imaging analysis software, we evaluated the cone-beam computed tomography (CT) images of two Korean patients who presented with retromolar canals. Retromolar canals were detectable on the sagittal and cross-sectional images of cone-beam CT, but not on the panoramic radiographs of the patients. Therefore, the clinician should pay particular attention to the identification of retromolar canals by preoperative radiographic examination, and additional cone beam CT scanning would be recommended.

하니콤 코어 샌드위치 구조 날개의 아음속 플러터 특성 (Subsonic Flutter Characteristics of a Sandwich Structure Wing with Honeycomb core)

  • 김유성;김동현
    • 한국항공운항학회지
    • /
    • 제14권2호
    • /
    • pp.17-26
    • /
    • 2006
  • The flutter characteristics of all movable tail wing with honeycomb sandwich structure have been studied in this study. The present wing model has a airfoil cross section and the linear variation of spanwise thickness. Structural vibration analysis is performed based on the finite element method using sandwich and beam elements. Unsteady aerodynamic technique used on the doublet lattice method has been effectively used to conduct the frequency-domain flutter analyses. The parametric flutter studies have been performed for various structural design parameters. Computational results on flutter stability due to the variation of structural parameters are presented and its related characteristics are investigated through the comparison of results.

  • PDF

Effect of Phase Transformation and Grain-size Variation on the Dry Sliding Wear of Hot-pressed Cobalt

  • Kim, Yong-Suk;Lee, Jong-Eun;Kang, Suk-Ha;Kim, Tai-Woong
    • 한국분말야금학회:학술대회논문집
    • /
    • 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
    • /
    • pp.879-880
    • /
    • 2006
  • Effect of phase transformation and grain-size variation of hot-pressed cobalt on its dry sliding wear was investigated. The sliding wear test was carried out against glass (83% $SiO_2$) beads at 100N load using a pin-on-disk wear tester. Worn surfaces, cross sections, and wear debris were examined by an SEM. Phases of the specimen and wear debris were identified by an XRD. Thermal transformation of the cobalt from the hcp $\varepsilon$ phase to the $\gamma$ (fcc) phase during the wear was detected, which was deduced as the wear mechanism of the sintered cobalt.

  • PDF

L-형 사형주조에서 Chill 효과에 관한 수치적 해석 (Numerical Analysis of the Chill Effect in L-shaped Sand Castings)

  • 김삼동;강춘식
    • 한국주조공학회지
    • /
    • 제5권2호
    • /
    • pp.109-117
    • /
    • 1985
  • A two dimensional analysis of the solidification phenomena has been simulated by IAD (Implicit Alternating Direction)method for L-shaped castings with external chills. The effect of chills has been studied with the variation of chill size, shape, and their materials, and also with the variation of the pouring temperature. Three kinds of cross-sectional shapes of chills such as triangle, square, and L-shape were chosen, and graphite, cast iron, and copper for their materials. It has been shown by the computation that the hot spot at the junction of L-shaped castings can not be removed by external chills, and that the distance between the inner corner and the hot spot on the line of symmetry, as well as the solidification time of castings depend only on VHC (Volumetric Heat Capacity).

  • PDF

다특성을 고려한 상황하에서의 공정능력지수에 관한 연구 (A Study on Process Capability Index using Loss Function Under the Muli-Attribute Conditions)

  • 김연희;김수열;박명규
    • 대한안전경영과학회:학술대회논문집
    • /
    • 대한안전경영과학회 2005년도 춘계학술대회
    • /
    • pp.503-521
    • /
    • 2005
  • Process capability indices are widely used in industries and quality assurance system. When designing the parameter on the multiple quality characteristics, there has been a study for optimization of problems, but there has been few former study on the possible conflicting phenomena in considertion of the correlations among the characteristics. To solve the issue on the optimal design for muliple quality characteristics, the study propose the expected loss function with cross-product terms among the characteristics and derived range of the coefficients of terms. Therefore, the analysis have to be required a multivariate statistical technique. This paper introduces to multivariate capability indices and then selects a multivariate process capability index incorporated both the process variation and the process deviation from target among these indices under the multivariate normal distribution. We propose a new multivariate capability index $MC_{pm}^{++}$ using quality loss function instead of the process variation and this index is compared with the proposed indices when quality characteristics are independent and dependent of each other,

  • PDF

기대손실함수를 이용한 다특성치 공정능력지수에 관한 연구 (A Study on Multiple Characteristics Process Capability Index using Expected Loss Function)

  • 김수열;조용욱;박명규
    • 대한안전경영과학회:학술대회논문집
    • /
    • 대한안전경영과학회 2004년도 추계학술대회
    • /
    • pp.69-79
    • /
    • 2004
  • Process capability indices are widely used in industries and quality assurance system. When designing the parameter on the multiple quality characteristics, there has been a study for optimization of problems, but there has been few former study on the possible conflicting phenomena in considertion of the correlations among the characteristics. To solve the issue on the optimal design for multiple quality characteristics, the study propose the expected loss function with cross-product terms among the characteristics and derived range of the coefficients of terms. Therefore, the analysis have to be required a multivariate statistical technique. This paper introduces to multivariate capability indices and then selects a multivariate process capability index incorporated both the process variation and the process deviation from target among these indices under the multivariate normal distribution. We propose a new multivariate capability index $MC_{pm}^{++}$ using quality loss function instead of the process variation and this index is compared with the proposed indices when quality characteristics are independent and dependent of each other.

  • PDF

Variation in Flower Color among Hybrids of Jeoktanshim Hibiscus syriacus L

  • Park Hyung-Soon;Cho Yoon-Jin;Chung Hun-Gwan;Jang Yong-Suk;Chung Dong-Jun
    • Plant Resources
    • /
    • 제8권3호
    • /
    • pp.250-257
    • /
    • 2005
  • This study was performed to provide basic information of the development and breeding of new cultivars of Hibiscus syriacus L., which have more beautiful and diverse flowers. Morphological characteristics of the flowers and leaves, and genetic variation of the flowers color of two Jeoktanshim-line cultivars, Bulsae and Pyungsung, were crossed each other. The result of the cross between Bulsae and Pyungsung are as follows: Mean flower height and width were 5.35 cm and 7.69 cm, respectively. Mean length and width of petal were 5.43 cm and 3.80 cm respectively, and mean length and width of flower pistil were 4.67 cm and 0.44 cm, respectively. The flower color of all ten individuals was the color of the Jeoktanshim-line, and Pyungsung, and all flower type were I-c type.

  • PDF

Anatomical variations of the tibial nerve and their clinical correlation

  • Anita Soraya Soetoko;Dina Fatmawati
    • Anatomy and Cell Biology
    • /
    • 제56권4호
    • /
    • pp.415-420
    • /
    • 2023
  • The tibial nerve is a branch of the sciatic nerve, which innervates the legs and feet. Anatomical variations of this nerve at the ankle are commonly found. The variation of the tibial nerve in its branching point and cross-sectional area (CSA) at the ankle is commonly related to clinical condition such as foot neuropathy. Knowledge of these variations can support the clinician in making appropriate clinical decisions. This review aims at providing knowledge on the anatomical variations of tibial nerve at ankle, as well as its clinical correlation. This review outlined the variation of the terminal branching point and CSA of the tibial nerve at the ankle in cadaveric and clinical studies.