• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.12
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• pp.2416-2419
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• 2009

We performed frequency response measurements of four tuning fork crystal oscillators with different sizes and analyzed their measured electrical equivalent circuit parameters of R, L, $C_S$, and $C_P$ as functions of the linear dimensions, length, width, and thickness. We observed that R and L showed an decreasing behavior with increasing length while $C_S$, and $C_P$ showed an increasing behavior. Similar dependences of the electrical parameters on thickness were also observed. On the contrary, any noticeable dependence of these parameters on width has not been found.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.559-559
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• 2012

We developed a new scheme for the highly sensitive near-field scanning optical microscope (NSOM) by using a dithering sample stage rather than a dithering probe. In the proposed scheme, the sample is directly loaded on one prong surface of a dithering bare tuning fork. Gap control between probe and sample is performed by detecting the shear force between an immobile fiber probe and the dithering sample. In a conventional NSOM, the Q factor drastically decreases from 7783 to 1000 or even to 100 by attaching a probe to the tuning fork. In our proposed NSOM, on the contrary, the Q factor does not change significantly, 7783 to 7480, when the sample is loaded directly to the tuning fork instead of attaching a probe. Consequently, the graphene sheets that cannot be observed by a conventional NSOM were clearly observed by the proposed method with sub-nanometer vertical resolution due to the extremely high Q factor.

• Journal of the Korean Society for Nondestructive Testing
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• v.27 no.4
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• pp.345-353
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• 2007

We have obtained a topographical image nondestructively for a Cu thin film in liquid using a near-field scanning microwave microscope (NSMM), its operating frequency was 3.5 to 5.5 GHz. We have kept a distance of 10 nm between tip and sample using a quartz tuning fork shear force feedback system. As an end of tip was attached to one prong of the quartz tuning fork has a length of 2 mm, the only tip of tuning fork was immersed in water tank. A loss cause by evaporation in water tank is regulated with actuator was connected to a supplementary tank. Moreover, using a revise program of LabView, we could increase the accuracy of a measurement in liquid.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.16 no.27
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• pp.73-82
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• 1993

In this paper, We determine the expected travel time for several forks Storage/Retrieval machine which is allowed multiple stops in aisle. When throughput is increased, We propose adding to fork number of each S/R machine rather than adding to number of S/R machine, We also describe such a model which determines the optimal number of each several forks S/R machine subject to constraints on the hourly throughput and warehouse dimensions. Numerical example is presented to compare warehouse shapes against each single fork, twin forks, triple forks S/R machine for various throughput values.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.335.2-335
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• 2002

Non-singular boundary element method (BEM) codes are developed in acoustics application. The BEM code is then used to calculate unknown boundary surface normal displacements and surface pressures from known exterior near field pressures. And then the calculated surface normal displacements and surface pressures are again applied to the BEM in forward in order to calculate reconstructed field pressures. (omitted)

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.302-305
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• 2003

In this paper, a feedline which is a shape of a fork is designed to improve a bandwidth of the microstrip slot antenna. To determine design parameters of the feedline, the characteristics of the microstrip slot antenna is analyzed by changing design parameters of the feedline. The microstrip slot antenna with the feedline of a shape of a fork has a wide band, from 1.7 GHz to 6.1 GHz for VSWR $\leq$2.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10c
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• pp.487-489
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• 2000

회선분배장치를 제어관리하는 W/S의 Daemon 중에서 Event 처리를 담당하는 EvtProc Daemon의 경우를 들어 효율적인 부하 분산 알고리즘을 제안하였다. 본 논문에서는 대량의 Event 발생 시 담당 프로세스가 연속적으로 fork, exec 하지 않고 일정시간 대기함으로써 fork와 exec의 오버헤드를 줄이고 같은 Op Code의 연이은 Even 발생에 대기중인 프로세스가 이를 처리함으로써 더욱더 오버헤드를 줄일 수 있다. 그리고 Event를 처리하는 Child 생성에 있어 주 Child가 부하분산을 담당하게 함으로써 효율적이고 안정적으로 관리할 수 있는 방안을 제시하였다.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.645-646
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• 2006

The oscillation amplitude of a probe tip is an important parameter to determine the resolution of atomic force microscopy (AFM) techniques. In this work, we introduce a new method for the measurement of the oscillation amplitude of a quartz tuning fork tip sub-nanometer resolution.

• Journal of Power Electronics
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• v.8 no.2
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• pp.109-120
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• 2008

In this paper, a novel delta/double-fork transformer based 18-pulse full-wave AC-DC converter is designed, modeled, simulated and developed to feed isolated DC varying loads. The proposed AC-DC converter is used for low voltage and large current DC loads in applications such as electrowinning, where isolation is required mainly for stepping down the supply voltage. The proposed converter improves power quality at AC mains and meets IEEE-519 standard requirements at varying loads.

• Proceedings of the Optical Society of Korea Conference
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• 2002.11a
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• pp.260-261
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• 2002

For Near-field Scanning Optical Microscopy measurements, the fiber tip is glued on the side of one of the tuning fork prongs vertically to its extended direction. Higher Q-factor is attainable in this geometry than in the arrangement with the fiber tip parallel to the prong. A simple mechanical design is applied to hold the fiber tip above the gluing point. The overall tuning fork-fiber tip assembly gives another advantage of the flexible Q-factor enhancement. With this treatment, Q-factor higher than 3000 is easily achievable. As an operating instance, a grating is scanned for its one dimensional topographical image.