• Title/Summary/Keyword: Hexagon

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Simulation of Small Clusters(II) -Geometries and Energies of$C_6-C_10$- (탄소 클러스터들에 관한 시뮬레이션(II) -$C_6-C_10$의 구조와 에너지-)

  • Lee, Jong-Mu
    • Korean Journal of Materials Research
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    • v.2 no.2
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    • pp.95-100
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    • 1992
  • The bond lengths, bond angles and energies of $C_6$ clusters are calculated by using the simulation technique based on some semiempirical potential energy functions, with the result that the equilibrium configuration of $C_6$ is a regular equilateral hexagon. The same simulations have been performed for linear and cyclic forms of $C_7-C_10$ clusters and the results show that the regular heptagonal, octagonal, nonagonal and decagonal forms are more stable than the linear forms of the respective clusters. Comparison of this result with the present author's previous result that the most stable configurations of $C_2-C_5$ are linear implies that the most stable configuration of the cluster changes from one-dimension al to two-dimensional one as the cluster size increases and that the critical cluster size is $C_6$.

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A Study on the Shape Evaluation using Non-contact Electromagnetic Measurement System (비접촉식 전자기 측정 시스템에서 자성물체의 형상판정에 관한 연구)

  • Kim, Jae-Min;Yun, Seung-Ho;Won, Hyuk;Park, Gwan-Soo
    • Journal of the Korean Magnetics Society
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    • v.20 no.2
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    • pp.45-51
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    • 2010
  • We suggest the algorithm that it detects volume and shape according with a variation of magnetic field in non-contact electromagnetic measurement system. It is possible to assess an object shape through a variation of magnetic field. The basic idea is compared a length difference with a variation of magnetic field in a detected object and a circle which modeled equivalent area. And the shape is detected to many calibration process that it is similar to signal pattern between a length difference and a variation of magnetic field in object and equivalent circle. This is the shape detection algorithm that use only the variation of magnetic field. In this paper, it has application to the shape detection algorithm about the object as hexagon, pentagon, rectangle, trigon. we can detect the object shape easily because the shape detection algorithm is only used to the variation of magnetic field.

Heat treatment induced morphological changes of $Ca^{++}$ implanted single crystal $Al_2O_3$ ($Ca^{++}$를 implant한 단결정 $Al_2O_3$에서 열처리에 의한 형태학적 변화)

  • 김배연
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.9 no.3
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    • pp.327-333
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    • 1999
  • Controlled Ca impurity implanted inner crack-like pore in the high purity alumina bi-crystal had been created by micro-fabrication technique, which includes ion implantation, photo-lithography, Ar ion milling, and hot press. The morphological change and the growth od crystals formed by heat treatment in Ca doped high purity single crystal alumina, were observed using optical microscopy. The dot was developed and hexagon like crystal appeared on inner surface of crack-like pore after heat treatment. Bar type crystals, probably CaO . $6Al_2O_3$, were observed on the inner surface of 100ppm Ca implanted specimen after 1 hour heat treatment at $1,500^{\circ}C$, but this bar type crystal disappeared after 1 hour heat treatment at $1,600^{\circ}C$. This disappearance means that there should be little increase of Ca solubility limit to alumina and/or changes of diffusion coefficient of Ca in alumina around this temperature.

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The Buckling Characteristics of Single-Layer Lamella Domes according to Support Position under Construction (단층라멜라 돔의 시공 중 서포트 위치에 따른 좌굴특성)

  • Kim, Cheol-Hwan;Suk, Chang-Mok;Jung, Hwan-Mok
    • Journal of Korean Association for Spatial Structures
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    • v.10 no.4
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    • pp.67-74
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    • 2010
  • Single layer latticed domes which have a mechanics property, a functional property, a aesthetic property and so on, occupies one part of long span space structures and after this, the using parts will be extended. The frame network pattern of single-layer latticed domes can be infinitely taken into account. The typical network patterns are triangular, square, hexagon, lamella and rib etc. It would take long time and cost too much to erect large roof structures with traditional erection techniques due to require of large number of temporary bracing and supports. The erection of large roof structures requires special techniques. As one of these special techniques is the Step-Up election method that utilizes jack-up supports and this will extremely saves time and cost to erect large roof structures. The objective of this study is to analysis the buckling characteristics of single-layer lamella domes according to the support number and position. From the result of this study, we obtained the fundamental data for the structural engineers who design the temporary support of large roof structures.

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In-vitro development of a temporal abutment screw to protect osseointegration in immediate loaded implants

  • Garcia-Roncero, Herminio;Caballe-Serrano, Jordi;Cano-Batalla, Jordi;Cabratosa-Termes, Josep;Figueras-Alvarez, Oscar
    • The Journal of Advanced Prosthodontics
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    • v.7 no.2
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    • pp.160-165
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    • 2015
  • PURPOSE. In this study, a temporal abutment fixation screw, designed to fracture in a controlled way upon application of an occlusal force sufficient to produce critical micromotion was developed. The purpose of the screw was to protect the osseointegration of immediate loaded single implants. MATERIALS AND METHODS. Seven different screw prototypes were examined by fixing titanium abutments to 112 Mozo-Grau external hexagon implants (MG Osseous$^{(R)}$; Mozo-Grau, S.A., Valladolid, Spain). Fracture strength was tested at $30^{\circ}$ in two subgroups per screw: one under dynamic loading and the other without prior dynamic loading. Dynamic loading was performed in a single-axis chewing simulator using 150,000 load cycles at 50 N. After normal distribution of obtained data was verified by Kolmogorov-Smirnov test, fracture resistance between samples submitted and not submitted to dynamic loading was compared by the use of Student's t-test. Comparison of fracture resistance among different screw designs was performed by the use of one-way analysis of variance. Confidence interval was set at 95%. RESULTS. Fractures occurred in all screws, allowing easy retrieval. Screw Prototypes 2, 5 and 6 failed during dynamic loading and exhibited statistically significant differences from the other prototypes. CONCLUSION. Prototypes 2, 5 and 6 may offer a useful protective mechanism during occlusal overload in immediate loaded implants.

An Evaluation of Clamping Characteristics for High Strength Bolts with Variable Bolt Lengths (고력볼트 길이에 따른 체결 특성 평가)

  • Lee, Kang Min;Kim, Kang Seok;Nah, Hwan Seon;Lee, Hyeon Ju;Oh, Kyung Hwan
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.15 no.6
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    • pp.127-134
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    • 2011
  • It has been reported that the length parameter of high strength bolts results in the variance in tensile loads. The required turn of nut for each length is specified in AISC RCSC specification. There is no specific regulation datum about the bolt length in the two national codes and specifications in Korea. Therefore this study focused on evaluating influence of the clamping torque subjected to length parameter of high strength bolts. Two types of high strength bolt specimens were manufactured and tested; High Strength Hexagon bolt specified in ASTM A490 and Torque Shear Bolt in KS B 2819. The length parameter ranged from 60mm(3d) to 140mm(7d). The torque, turn of nut, and the clamping force were analyzed to review whether length parameter affects on the required tensile strength. To evaluate the effects of the length parameter on the torque and turn of nut for the required strength and clamping force, statistical analysis was also carried out.

Morphological characterization of Vibrio alginolyticus specific bacteriophage isolated from fish farms on west coast of Korea (서해안 양식장에서 분리한 Vibrio alginolyticus의 특이 bacteriophage에 대한 구조적 특성)

  • Heo, Yong Ju;Lee, Chan Heun;Baek, Min Suk;Ahn, Hyun Mi;Hwang, Yo Sep;Park, Kwan Ha;Choi, Sang Hoon
    • Journal of fish pathology
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    • v.25 no.3
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    • pp.165-172
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    • 2012
  • Vibrio alginolyticus (V. alginolyticus), which is one of bacterial pathogens evoking severe infection in fish and shellfish as well as in human has been found at high frequency around all coast areas in Korea. Both V. alginolyticus and V. alginolyticus specific bacteriophage were isolated from sea water and various fishes from fish farms on west coast in Korea. In a morphological study based on electron microscope, the purified phage appeared to be composed of hexagon head of 60 nm and short tail of 20 nm. In the denatured SDS-PAGE analysis, the structural proteins of the phage were found to be 7 different protein fractions ranging from 37.8 to 198 kda. The kind of nucleic acid of the phage was ascertained to a double stranded DNA.

Polygon-shaped Filters in Frequency Domain for Practical Filtering of Images (현실적 영상 필터링 방법을 위한 주파수 영역에서의 다각형 형태 필터의 모델링)

  • Kim, Ju-O;Kim, Ji-Su;Park, Cheol-Hyeong;Lee, Deok-Woo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.3
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    • pp.1-7
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    • 2019
  • In this paper, we propose an approach to design a practical filter and a mathematical modeling for images. In the areas of signal processing, including high-dimensional image processing, the filtering process has been fundamental and crucial in diverse practical applications such as image processing, computer vision, and pattern recognition. In general, the ideal filter is modeled as circular-shaped in the 2D frequency domain as the rectangular shape is ideal for the 1D frequency domain. This paper proposes an approach to modeling practical and efficient image filter in the 2D frequency domain. Instead of employing a circular-shaped filter, this study proposes a polygon-shaped filter inspired by the concept of a hexagon cellular system for frequency reuse in wireless communication systems. By employing the concept of frequency reuse, bandwidth efficiency is also achieved in the frequency domain. To substantiate the proposed approach, quantitative evaluation is performed using PSNR.

A Study on the Spatial Position Problem of PM Monitoring Stations Using Voronoi Technique and Density Analysis (보로노이 기법과 밀도분석을 활용한 미세먼지 측정소 공간적 위치 문제 연구)

  • Jeong, Jong-Chul
    • Journal of Cadastre & Land InformatiX
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    • v.48 no.2
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    • pp.185-195
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    • 2018
  • In the Seoul Metropolitan City, the PM(pariculate matter) application used by the citizens provides the PM concentration of the nearest monitoring stations located on the PM monitoring stations. Currently, the selecting method of the PM monitoring network considered by the Ministry of Environment is based on considering the monitoring station distribution and population density only. In this study, we analyzed the distance between PM monitoring station and the administrative center point in addition to the above considerations. The number of test sites was verified and the range of coverage of each monitoring stations was indicated by using the Voronoi algorithm and hexagon grid. The spatial position problem of the PM monitoring station was suggested by spatial data analysis. The variables of spatial data analysis are single-family houses, apartments, $1^{st}$ class neighborhood, $2^{nd}$ class neighborhood, garbage disposal plant, hazardous material disposal facility, factory, and the density map. The analysis result of the selection criterion considering the additional variables for new PM monitoring stations was presented, in addition to the selection criteria provided by the Ministry of Environment.

Numerical Analysis of Concentration Polarization for Spacer Configuration in Plate Type Membrane Module (평판형 분리막 모듈 내 스페이서 형태에 따른 농도분극에 관한 수치해석)

  • Shin, Ho Chul;Chung, Kun Yong
    • Applied Chemistry for Engineering
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    • v.22 no.6
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    • pp.703-710
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    • 2011
  • As the spacer in the membrane module provide the channel space to flow the feed solution smoothly and induce the flow turbulence, it could help to reduce both the concentration polarization and to take the long-term operation of membrane modules with high permeate flux by mixing the accumulated contaminants on the membrane surface into the bulk solution. In this study, the concentration distribution in membrane module with respect to the spacers which have the cross-sectional shapes of circle, cross, diamond and hexagon, the angles of spacer configuration, solute rejection and permeate flux were interpreted and optimized numerically using the "COMSOL Multiphysics" software. The concentration on the membrane surface was kept the lowest level for the cross-shape among the above four types of spacers. Also the 30 degree spacer configuration was showed as the most efficient case. The concentrations on the membrane surface at the module outlet for without spacer and the cross shape with the 30 degree spacer configuration were 2.09 and 1.29 times higher than those at inlet, respectively. The reduction effect of concentration polarization increased rapidly as the permeate flux increased.