• 한국축산시설환경학회지
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• 제7권2호
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• pp.77-82
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• 2001

This research was carried out to investigate the daily amount and characteristics of wastewater produced from bucket milkers, pipeline, tandem ad herringbone milking system for washing operations after milking included 28 dairy farms. The average amount of wastewater produced from milking system was 9.8l/head/day. The amount of wastewater varied from a low of 8.2 litters/head/day(pipeline milking system) to 13.4 litter/head/day(herringbone milking system). The moisture content, Biochemical Oxygen Demand($BOD_5$), Chemical Oxygen Demand($COD_{Mn}$), Suspended Solids(SS), Total Nitrogen(T-N) and Total Phosphorus(T-P) concentration of wastewater were 99.9%, 394mg/l, 417.3mg/l, 1,201.3mg/l, 3.78mg/l, 0.51mg/l.

• 한국산학기술학회논문지
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• 제12권12호
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• pp.5412-5419
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• 2011

산업의 발달에 따른 각종기기 장치들의 고속화, 소형화, 정밀화로 인해 고속 스핀들의 필요성은 점점 커지고 있다. 또한 공기동압베어링은 스테이지 모션에 대해서 무마찰 실현을 위해서 웨이퍼 생산용 광학 리소그래피 분야에도 적용된다. 공기동압베어링은 마찰에 의한 동력손실과 열 발생이 적어 고속회전에 유리하고 고정밀 회전이 가능하기 때문에 고속 고정밀 스핀들 시스템 및 하드 디스크 드라이브에 사용될 수 있다. 본 연구에서는 축 하중 지지를 위해 헤링본 홈 형상을 가지는 공기동압베어링의 성능에 대한 수치해석을 수행하였다. 또한 본 연구에서는 공기동압베어링을 제작하기 위해서 기존의 기계 가공방법과는 다른 비접촉식 초정밀 가공 방법인 마이크로 전기화학가공에 의한 방법으로 마이크로 그루브 가공을 수행하였고, 수치해석 프로그램을 이용하여 전극의 간극, 전해용액 농도, 가공시간 등 이론적인 수치를 시뮬레이션 하였다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1996년도 제23회 학술대회
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• pp.36-40
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• 1996

A numerical analysis is performed about the static and dynamic characteristics of the oil-lubricated herringbone-grooved journal bearing which has circular groove profile. Some tests of jitter and W/F measurements are carried out to verify the performance of the newly designed drum assembly.

• Bulletin of the Korean Chemical Society
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• 제31권8호
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• pp.2247-2254
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• 2010

The surface structures of copper phthalocyanine (CuPc) thin films deposited on sulphur-passivated and plane perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA)-covered InAs(100) surfaces have been studied by low energy electron diffraction (LEED) and van der Waals (vdW) intermolecular interaction energy calculations. The annealing to $300^{\circ}C$ and $450^{\circ}C$ of $(NH_4)_2S_x$-treated InAs(100) substrates produces a ($1{\times}1$) and ($2{\times}1$) S-passivated surface respectively. The CuPc deposition onto the PTCDA-covered InAs(100) surface leads to a ring-like diffraction pattern, indicating that the 2D ordered overlayer exists and the structure is dominantly determined by the intermolecular interactions rather than substrate-molecule interactions. However, no ordered LEED patterns were observed for the CuPc on S-passivated InAs(100) surface. The intermolecular interaction energy calculations have been carried out to rationalise this structural difference. In the case of CuPc unit cells on PTCDA layer, the planar layered CuPc structure is more stable than the $\alpha$-herringbone structure, consistent with the experimental LEED results. For CuPc unit cells on a S-($1{\times}1$) layer, however, the $\alpha$-herringbone structure is more stable than the planar layered structure, consistent with the absence of diffraction pattern. The results show that the lattice structure during the initial stages of thin film growth is influenced strongly by the intermolecular interactions at the interface.

• KSTLE International Journal
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• 제4권1호
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• pp.18-26
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• 2003

Recently, fluid dynamic bearings (EDBs) have important applications in miniature rotating machines such as those found in the computer information storage industry, due to their outstanding low acoustic noise and NRRO (Non-Repeatable Run Out) characteristics. This research investigates the dynamic behavior of fluid dynamic bearings composed of hydrodynamic herringbone groove journal and spiral groove thrust bearing. The five degrees of freedom of FDB are considered to describe the real motion of a general rotor bearing system. The Reynolds equation and five nonlinear equations of motion for the dynamic behavior are solved simultaneously, The incompressible Reynolds equation is solved by using the finite element method (FEM) in order to calculate the pressure distribution in a fluid film and the five equations of motion by using the Runge-Kutta method. The reaction forces and moments are obtained by integrating the pressure along the fluid film. Numerical results are validated by comparing with the previously published experimental and numerical results. As a result the dynamic behavior of FDB spindle such as orbit, floating height, and angular orbit is investigated by considering the conical motion under the static and dynamic load conditions.

• Bulletin of the Korean Chemical Society
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• 제28권8호
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• pp.1358-1362
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• 2007

The structures, energetics and transfer integrals of the acene tetramers up to pentacene are investigated with the ab initio molecular orbital method at the level of second-order Møller-Plesset perturbation theory (MP2). Calculated geometries for the herringbone-style structures found in the crystal structure were characterized as local minima, however the geometrical discrepancy between crystal and MP2 theoretical structure is reasonably small. The binding energy of pentacene tetramer was calculated up to 40 kcal/mol (MP2/6-31G(d)) and about 90 kcal/mol (MP2/aug-cc-pVDZ), and the latter seems to be too much overestimated. The tendency of the hole transfer integrals computed with ab initio MP2/3-21G(d) geometry is well agreement with those estimated with crystal structure with some discrepancy, and the gradual increment of the transfer integrals at the crystal geometry is attributed to mainly packing structure rather than the intrinsic property of acene such as a size of acene.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2006년도 춘계학술대회 논문집
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• pp.31-34
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• 2006

The characteristic of carbon nano fiber (CNF) as electron emitters was described. Carbon nano fiber (CNF) of herringbone was prepared by thermal chemical vapor deposition(CVD), mixed with binders and conductive materials, and then were formed by screen-printing process. In order to increase effectively field emissions, the surface treatment of rubbing & peel-off was applied to the printed CNF emitters on cathode electrode. The measurements of field emission properties were carried out by using a diode structure inline vacuum chamber. CNF of herringbone type showed good emission properties that a turn on field was as low as $2.5V/{\mu}m$ and current density was as large as $0.15mA/cm^2$ of $4.5V/{\mu}m$ with electric field. After the vacuum packaged panel of 5-inch in diagonal, the measured white brightness was as high as $7000cd/m^2$ at 1900V of anode and 700V of gate voltage.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2001년도 제34회 추계학술대회 개최
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• pp.197-203
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• 2001

In this paper, numerical analyses were undertaken to calculate the static and dynamic performances of step-pocket, inward pumping spiral grooved, outward pumping spiral grooved and herringbone grooved bearings. For each bearing, optimal values for various design parameters were obtained to maximize the load capacity and the stiffness and bearing performances were calculated. The optimized performances of these bearings were compared to conclude that the performance of step-pocket bearing is better than the other bearings.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 하계학술발표대회 논문집
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• pp.58-58
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• 2007

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.379-380
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• 2006

Recently, in spindle motors for hard disk drive (HDD) devices, fluid dynamic bearings (FDB) with herringbone grooves have come to be used instead of ball bearings due to the demand for high density recording of the devices etc. In this study, a 5-lobe bearing with high bearing stiffness using a sintered material was developed, and the bearing performance was examined by simulated calculations and experiments. As a result, it was clarified that the 5-lobe bearing had the required performance for practical use in the spindle motor for HDD