• Kyungpook Mathematical Journal
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• v.57 no.2
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• pp.223-232
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• 2017

We classify the extreme and exposed symmetric bilinear forms of the unit ball of the space of symmetric bilinear forms on ${\mathbb{R}}^2$ with hexagonal norms. We also show that every extreme symmetric bilinear forms of the unit ball of the space of symmetric bilinear forms on ${\mathbb{R}}^2$ with hexagonal norms is exposed.

• Journal of the Korean earth science society
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• v.24 no.1
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• pp.36-45
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• 2003

This study is made for examining the characteristics of the lead-zinc deposition from the mineralogy of pyrrhotite at the Yeonhwa 1 Mine, Korea. The pyrrhotite of the Yeonhwa 1 mine is divided two species; the pynhotites I and II. The pyrrhotite I that represents the product in Stage II mineralization is characterized by hexagonal pyrrhotite occurring as the mechanical mixtures of hexagonal and monoclinic phases with various proportion. These mixtures might be formed from 'primary' hexagonal pyrrhotite by the subsequent retrograde reaction and/or by the influence of later mineralization in Stage III. Whereas the pyrrhotite II crystallized out in later Mineralization Stage III (hydrothermal stage) is always monoclinic variant with ferromagnetic properties; no two phase mixtures have been recognized.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.05a
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• pp.197-200
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• 2001

In the multi-stage former, manufacture of hexagonal fitting nut was generated in a defective products about $70{\~}80\%$. Defective products reduced in a product stiffness and increased a product cost. Defects for manufacturing hexagonal fitting nut caused in a increase of ductile fracture value. So in the study, a preform designed to reduce ductile fracture value and designed preform verified through the finite element simulation. In conclusion, Ductile fracture value reduced if A round dimension of preform reduced and a part of opposition angle contributed in Plenty a volume.

• Journal of Korea Multimedia Society
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• v.20 no.12
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• pp.2009-2015
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• 2017

A two-dimensional lens is required to reproduce both the horizontal and vertical parallax through an autostereoscopic 3D display. Among the two-dimensional lenses, a hexagonal micro lens array (MLA) having good optical efficiency is mainly used. However, the hexagonal MLA has complex geometric features. The first feature is that the lens cells are zigzagged in the vertical direction, which should be reflected in the view number calculation for each sub-pixel. The second feature is that the four sides of a hexagonal lens cell are tilted, requiring a more careful view index assignment to the lens cell. In this paper, we propose a sub-pixel multiplexing scheme suitable for the features of the hexagonal MLA. We also propose a view-overlay algorithm based on a two-dimensional lens and compare subjective image quality with existing view-selection through autostereoscopic 3D display implementation.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.222-224
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• 2002

In proton and heavy ion radiotherapy, compensators are required to modify the energy of heavy ion, to compensate the local difference of tumor depth. Conventional compensators have to be created, exchanged, and stored for each patient and for each irradiation directions. A Cylinder Type Liquid Variable Compensator is and is under development. Hexagonal cylinders will be arranged in honeycomb structure. In which air and fluid are divided by hexagonal pistons. The position of each piston will be changed in each cylinder for adjusting the thickness of fluid for variable compensator. The location of each hexagonal piston is determined by each controlling cylinder connected to the hexagonal cylinder by inlet pipes of fluid. Each controlling cylinder includes controlling a piston, which is moved mechanically. Each controlling cylinder is to be moved by a motor driven by a computer.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.11a
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• pp.15-20
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• 1996

We present the result of physical studies for three integral-type burnable absorbers of gadolinia, erbia and IFBA, in the hexagonal fuel assembly. The analysis of nuclear characteristics for gadolinia and IFBA cases shows that the spectrum hardening of hexagonal fuel assembly compared to rectangular one leads to smaller reactivity hold-down worth(RHW) and less change of MTC in the negative direction per insertion of one burnable absorber rod. Erbia case, on the other hand, exhibits reversed trend in RHW and MTC due to the enhanced absorption of large resonance of Erbium at 0.5 eV It turns out to be that Erbia performs best in terms of minimizing the peak pin power and maintaining as more negative MTC as practically attainable during the entire operational phase, and IFBA provides the least residual reactivity penalty at EOC. Therefore, we take Erbium as the suitable burnable absorber and provide optimal designs of 60, 120, 180, 240 and 300 erbia-shimmed hexagonal fuel assemblies with regard to minimizing the peak pin power.

• Tribology and Lubricants
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• v.24 no.6
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• pp.368-373
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• 2008

This paper will investigate the friction characteristics of a 100m Hexagonal Array, Micro-scale Dimple Pattern, on bearing steel. These characteristics are researched by utilizing a pin-on-disk wear test machine, under various test conditions. The reduction of friction is a necessary requirement for the improved efficiency of this machine. As the speed increases, there is a decrease in the effect of the dimple of friction characteristic, with substantially little change to density. Conversely, as the load increases, the dimple pattern grows larger, resulting in a difference in the texture of these two components. At a dimple density of 10% the friction characteristic is easily demonstrated, with a consistent change in both speed and load.

• Journal of electromagnetic engineering and science
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• v.6 no.1
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• pp.53-61
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• 2006

In this paper, we present parametric studies for the optimum design of a hexagonal plate monopole antenna. The dependence of the antenna performance on various geometric parameters is investigated using a commercial electromagnetic software, from which an optimum design of a hexagonal plate monopole antenna is derived. Guidelines for determining initial parameter values are given. The diameter of the circular ground plane is minimized tlo 1/5 wavelength at the lowest operating frequency. The antenna impedance matching is controlled by adjusting the gap between the plate and the ground plane, the plate base width, and the base bevel angle. The antenna proposed in. this paper shows a reflection coefficient less than -10 dB and a $2.0{\sim}6.2$ dBi gain over $3{\sim}20$ GHz frequencies.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.204-207
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• 2000

In this paper, we have studied the effect of doped with B-Bi-Zn on properties (microstructure, density, shrinkage, permeability as a function of frequency, etc.) of hexagonal-ferrite for high frequency chip-inductor material about several GHz. The permeability were analyzed by impedance analyzer(100 kHz~40 MHz) and network analyzer(30 MHz~3 GHZ). As a result of the characteristics, the B-Bi-Zn glass ceramic was used to lower the sintering temperature for additive as a function of frequency from 100 kHz to 1.8 GHz showed constant tends. The maximum imaginary value of complex permeability was observed near the resonance frequency of 2 GHz.

• Tribology and Lubricants
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• v.25 no.1
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• pp.25-30
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• 2009

본 연구에서는 pin-on-disk 마찰 시험기를 통하여 Hexagonal 배열 $40{\mu}m$ Dimple 패턴의 효과를 실험하였다. 마찰 실험은 미끄럼 속도가 $0.06{\sim}0.34m/s$로 하였으며 마찰하중은 $20{\sim}100\;N$의 범위로 하였고, Dimple의 밀도는 $10{\sim}25%$의 범위로 제작하여 실험을 행하였다. 일반적으로 속도가 증가하고 하중이 감소할수록 마찰계수는 감소하는 경향을 나타내었으며, Dimple에 의한 마찰저감 효과는 속도가 $0.14{\sim}0.26m/s$의 범위에서 나타났다. $40{\mu}m$ Hexagonal 배열 Dimple 패턴의 마찰 특성에서는 밀도가 12.5%에서 가장 좋은 경향을 나타내었다.