• 한국수산과학회지
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• 제41권2호
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• pp.140-149
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• 2008

This study evaluated the efficiency of an oil fence and spreading devices for one vessel in a towing tank. A series of model experiments and numerical calculations were conducted using an existing oil fence for two vessels and a new method for one vessel. Models of the oil fence and spreading devices were constructed on $1/20^{th}$ scale from waterproofed nylon fabric and canvas. The tensions acting on the model of the oil fences and the horizontal distance between the spreading devices were calculated numerically while the oil fences were being towed. The results were extremely close to the results of the model experiments. The ratio of the opening width to the total length of the oil fence, which shows the efficiency of the oil fence for one vessel, was 49.7% in 0.4 m/sec. Therefore, the proposed oil fence system should be very useful for oil containment at sea. As the opening width of the oil fence is not proportional to the length of the towing rope, it may be reasonable to maintain the towing rope at approximately 100 m. Furthermore, a reasonable towing speed, when operating the oil fence for one vessel equipped with spreading devices, was within 0.4 m/sec.

• Transactions on Electrical and Electronic Materials
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• 제16권4호
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• pp.183-186
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• 2015

This research investigates the impact of charge spreading on the data retention of three-dimensional (3D) silicon-oxide-nitride-oxide-silicon (SONOS) flash memory where the charge trapping layer is shared along the cell string. In order to do so, this study conducts an electrical analysis of the planar SONOS test pattern where the silicon nitride charge storage layer is not isolated but extends beyond the gate electrode. Experimental results from the test pattern show larger retention loss in the devices with extended storage layers compared to isolated devices. This retention degradation is thought to be the result of an additional charge spreading through the extended silicon nitride layer along the width of the memory cell, which should be improved for the successful 3-D application of SONOS flash devices.

• 한국통신학회논문지
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• 제41권11호
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• pp.1349-1355
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• 2016

5G 이동통신 예상 시나리오 중 하나로, 저 용량 전송을 하는 수많은 모바일 단말 및 센서 들이 급증할 것으로 예상하고 있다. 이러한 저 용량, 초 다수 기기들을 지원하기 위해서 저 복잡도를 갖는 단일 반송파 시스템이 고려될 수 있다. 이러한 조건을 만족시키기 위해, 본 논문에서는 단일 반송파 기반의 기존 CDMA(Code Division Multiple Access) 시스템 보다 2배의 유저를 수용할 수 있는 복소수 스프레딩을 사용하는 CDMA 시스템을 제안한다. 본 논문에서 제안하는 시스템은 Multi-level BPSK(Binary Phase Shift Keying) 변조를 사용한다. 제안하는 시스템은 실수와 허수로 구성된 칩 코드를 이용하여 전송하고자 하는 심볼을 스프레딩 한다. 시뮬레이션의 결과로 기존 CDMA 시스템에 비하여 BER(Bit Error Rate) 성능이 약 3dB 열화되나, 기존의 CDMA 시스템 대비 2배의 유저를 수용할 수 있어서 다중접속 효율 향상을 확인하였다.

• 한국입자에어로졸학회지
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• 제18권4호
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• pp.129-136
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• 2022

The line width of circuits in semiconductor devices continues to decrease down to a few nanometers. Since nanoparticles attached to the patterned wafer surface may cause malfunction of the devices, it is crucial to remove the contaminant nanoparticles. Physical cleaning that utilizes momentum of liquid for detaching solid nanoparticles has recently been tested in place of the conventional chemical method. Dropwise impaction has been employed to increase the removal efficiency with expectation of more efficient momentum exchange. To date, most of relevant studies have been focused on drop spreading behavior on a horizontal surface in terms of maximum spreading diameters and average spreading velocity of drop. More important is the local liquid velocity at the position of nanoparticle, very near the surface, rather than the vertical average value. In addition, there are very scarce existing studies dealing with microdroplet impaction that may be desirable for minimizing pattern demage of the wafer. In this study, we investigated the local velocity distribution in spreading liquid film under various impaction conditions through the CFD simulation. Combining the numerical results with the particle removal model, we estimated an effective cleaning diameter (ECD), which is a measure of the particle removal capacity of a single drop, and presented the predicted ECD data as a function of droplet's velocity and diameter particularly when the droplets are microns in diameter.

• Journal of Acupuncture Research
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• 제21권6호
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• pp.209-219
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• 2004

Objective : This study was designed to compare acupuncture sensation index among three different acupuncture devices. Methods : A, B and C acupuncture devices were inserted into Quchi(LI 11) of the subjects. After 5 minutes the subjects completed a questionnaire rating the intensity of 21 kinds of acupuncture sensation; hurting, penetrating, sharp, aching, intense, spreading, radiating, tingling, pricking, stinging, pulling, heavy, dull, numb, electric, shocking, hot, burning, cool, pulsing, and throbbing. We compared subjective evaluations of acupuncture sensation among the groups. Results : The acupuncture sensation index when administrated among three different acupuncture devices(A, B and C) was not significantly different. The acupuncture sensation of B acupuncture devices showed significant difference than A or C in Spreading, Dull, Numb item. But, the other items of acupuncture sensation were not significantly different among three acupuncture devices. Conclusions : We found that acupuncture sensation index when administrated among three different acupuncture devices. Further study is needed to know different acupuncture sensation among acupuncture devices.

• 대한전기학회논문지
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• 제41권3호
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• pp.267-273
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• 1992

An advanced on-resistance model of VDMOS devices in the low voltage regimes is proposed and verified by 2-D device simulations. The model considers the lateral gaussian doping profiles in the channel region and exact current spreading angles in the epitaxial layer for both linear and cellular geometries by employing the conformal mapping, It is found out that the on-resistance of low voltage VDMOS may be overestimated considerably if it is analyzed by the conventional method. The 2-D device simulation results show that the proposed model is valid for the VDMOS devices in the low voltage regimes.

• 한국전기전자재료학회논문지
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• 제15권11호
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• pp.969-975
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• 2002

Thin film transistors(TFT) were made based on the polycrystalline Si (poly-Si) crystallized by sequential lateral solidification(SLS) method. The electrical characteristics of the devices were analyzed. n-type TFTs did not show a superior characteristics compared to p-type TFTs. We analyzed the causes of the failure by focused ion beam(FIB) analysis and automatic spreading resistance(ASR) measurement, to study the structural integrity and the doping distribution, respectively. FIB showed no structural problems but it revealed a non-intermixed layer in the contact holes between the polysilicon and the aluminum electrode. ASR analyses on poly-Si layer with various doping concentrations and activation temperatures showed that the inadequately doped areas were partially responsible for the inferior behavior of the whole device.

• Applied Microscopy
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• 제47권3호
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• pp.95-100
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• 2017

High resolution measurements of the carrier profile in semiconductor devices is required as the semiconductor industry progresses from the 10-nm lithography node to 7-nm and beyond. We examine the factors which determine the resolution of the present method of scanning spreading resistance microscopy as well as such factors for the newer method of scanning frequency comb microscopy that is now under development. Also, for the first time, we consider the sensitivity of both methods to the location of heterogeneities in the semiconductor. In addition, mesoscopic effects on these measurements are considered for the first time. Two simple analytical models are extended to study the sensitivity to heterogeneities as well as mesoscopic effects.

• Applied Microscopy
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• 제42권4호
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• pp.223-227
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• 2012

Focused Ion Beam (FIB) systems have incorporated versatile nanomanipulators with inherent sophisticated machining capability to characterize the electrical properties of highly miniature components of electronic devices. Carbon fibers were chosen as a model system to test the applicability of nanomanipulators to microscale electronic materials, with special emphasis on the direct current current-voltage characterizations in terms of electrode configuration. The presence of contact resistance affects the electrical characterization. This resistance originates from either i) the so-called "spreading resistance" due to the geometrical constriction near the electrode - material interface or ii) resistive surface layers. An appropriate electrode strategy is proposed herein for the use of FIB-based manipulators.

• International Journal of Computer Science & Network Security
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• 제23권7호
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• pp.149-154
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• 2023

Internet of Things (IoT) is now spreading everywhere. It's the technology of every person's need so we can't step back from IoT but we can secure it as it is spreading quickly so it has greater chances of danger and being misused. There is an urgent need to make IoT devices secure from getting cracked or hacked. A lot of methods had tried and still trying to mitigate IoT security issues. In this paper Blockchain is going to be the solution of most of the IoT issues or problems. We have discussed or highlighted security issues with centralized IoT and then provided solution of such security challenges through the use of blockchain because is based on a decentralized technology that is hard to modify or update.