• Wind and Structures
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• 제17권4호
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• pp.419-433
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• 2013

This paper investigates the vertical profiles of horizontal mean wind speed and direction based on the synchronized measurements from a Doppler radar profiler and an anemometer during 16 tropical cyclones at a coastal site in Hong Kong. The speed profiles with both open sea and hilly exposures were found to follow the log-law below a height of 500 m. Above this height, there was an additional wind speed shear in the profile for hilly upwind terrain. The fitting parameters with both the power-law and the log-law varied with wind strength. The direction profiles were also sensitive to local terrain setups and surrounding topographic features. For a uniform open sea terrain, wind direction veered logarithmically with height from the surface level up to the free atmospheric altitude of about 1200 m. The accumulated veering angle within the whole boundary layer was observed to be $30^{\circ}$. Mean wind direction under other terrain conditions also increased logarithmically with height above 500 m with a trend of rougher exposures corresponding to lager veering angles. A number of empirical parameters for engineering applications were presented, including the speed adjustment factors, power exponents of speed profiles, and veering angle, etc. The objective of this study aims to provide useful information on boundary layer wind characteristics for wind-resistant design of high-rise structures in coastal areas.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.371-375
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• 2002

Emissions of thermionic cathodes and field emitters were studied using a cathode emission profiler which works based on the anode scanning method. Findings about impregnated cathodes in thermal activation and gas poisoning processes are shown. Effects of surface treatments for field emitters are studied from the viewpoint of emission profiles and characteristics of the emitters.

• 한국진공학회지
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• 제1권1호
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• pp.28-31
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• 1992

초고진공 시스템을 구성할 때 고려할 요소는 진공용기의 세척과 표면조도, 진공용 기의 재질, 기타 방출기체의 요인이다. 초고진공용기를 전해연마 처리하였으며, 처리한 진공 용기의 표면조도를 표면 조도기(surface profiler)로 측정하였다. 진공용기는 직경 300mm이 고 높이는 720mm로 하였다. 설치한 초냉각 펌프로 18시간 배기후 2.9 $\times$ 10-10Torr를 얻었 으며, 계속해서 초고진공용기를 250에서 60시간 baking 후 최저도달 압력이 3.08 $\times$ 10-11torr에 도달하였다 누드 이온게이지를 이용하여 초고진공용기의 최저도달압력과 누출비 를 측정하였다.

• International Journal of Precision Engineering and Manufacturing
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• 제7권1호
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• pp.9-12
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• 2006

A spectral analysis and numerical simulation are employed to assess the effects of the stylus tip radius on measuring surface profiles. Original profiles with fractal spectral densities are generated and then are numerically traced with circular tipped stylus. Instead of their spectral densities, the accumulative power spectrums of traced profiles are analyzed. It is shown that the minimum wavelength of traced profile relates directly to the radius r of the stylus tip and the root-mean-square (rms) roughness ${\sigma}_o$ of original profile. From this accumulation spectral analysis, a formula is developed to estimate the minimum wavelength of traced profile. By using the concept of the minimum wavelength, an appropriate stylus tip radius can be chosen for the given rms roughness ${\sigma}_o$ of the profile.

• Journal of the Korean Wood Science and Technology
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• 제24권4호
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• pp.87-92
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• 1996

When cutting 2.0cm-thick red oak and hard maple with an air-jet-assisted carbon-dioxide laser of 2kW output power, maximum feed speed at the point of full penetration of the beam decreased with increasing the angle between grain and cutting direction. Feed speed averaged 3.75 and 3.38 meters per minute for red oak and hard maple, respectively. Gray-level of laser-cut surfaces were analyzed by image analysis system. The highest gray level of laser-cut surface was obtained when red oak was cut parallel to grain by laser. Surface profiler was used to scan the sawn and laser-cut surfaces. Center line average roughnesses of laser-cut surfaces were higher than those of sawn surfaces. Scanning electron micrographs showed the cell walls which were melted by laser.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전기물성,응용부문
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• pp.49-52
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• 2003

Single crystalline silicon (SCS) was adopted for a reliable micromirror array of biochip fabrication applications. SCS has excellent mechanical properties and smooth surface, which is the best material for micromirror devices. The mirror array has $16{\times}16$ micromirrors and each mirror has a $120{\mu}m{\times}100{\mu}m$ reflective surface. The micromirror has simple torsional beam springs and electrostatic force was used for driving. The designed tilting angle was $9.6^{\circ}$, and the tilting angles were measured according to applied voltages. The surface roughness was measured by a laser profiler. The response time was measured using He-Ne laser and position sensitive diode (PSD), and the lifetime was checked for reliability proof.

• 방사선산업학회지
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• 제5권3호
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• pp.243-247
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• 2011

In this study, a convenient method for the selective immobilization of single strand DNA (ssDNA) on a polymer surface was described. A positively charged polyelectrolyte, poly(diallyldimethylammonium chloride) (PDDA), was spin-coated on a tissue culture petridish and the micropatterns of the PDDA were formed by selective ion implantation through a pattern mask. The surface property of the implanted PDDA was investigated by using a surface profiler and FT-IR spectrometer. Cy3-labeled ssDNA was selectively immobilized on the PDDA patterns through ionic interaction and thus, well-defined ssDNA patterns were obtained.

• 한국해양학회지
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• 제24권4호
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• pp.172-183
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• 1989

1987년 9월 한국해협에서 수집한 ADCP의 음파산란 신호를 이용하여 음향적으로 동물플랑크톤의 수직적인 분포를 추정하였다. ADCP의 음파산란 자료는 8m 두께의 해수내에 존재하는 산란체에 의한 음파산란 신호로써 이를 근거로 계산한 동물플랑크톤의 개체수는 계절 수온약층이 존재하는 수심 40m 부근을 경계로 하여 하층보다 상층에서 많은 양이 나타남을 보이고 있다. 한편 한국해협 저층의 냉수층에서도 상당량이 존재함을 나타내고 있다. 표층의 개체수 분포는 부산연안에서 많은 양을 보이다가 한국해협 중앙부까지는 거의 일정하며 다시 대마도 부근으로 갈수록 증가함을 볼 수 있다. 이러한 분포양상은 기존의 방법에 의한 분포와 잘 일치함을 보여주고 있다. 따라서 동물플랑크톤의 시공간적 분포 파악을 위해 ADCP를 이용한 음향학적인 접근방법의 가능성을 보여주었다.

• 한국기계가공학회지
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• 제19권2호
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• pp.69-74
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• 2020

In this study, we proposed a method for surface profiling aspheric lens molds using a precision displacement sensor with a spatial scanning mechanism. The precision displacement sensor is based on the confocal principle using a broadband light source, providing a 10 nm resolution over a 0.3 mm measurable range. The precision of the sensor, depending on surface slope, was evaluated via Allan deviation analysis. We then developed an automatic surface profiling system by measuring the cross-sectional profile of a lens mold. The precision of the sensor at the flat surface was 10 nm at 10 ms averaging time, while 200 ms averaging time was needed for identical precision at the steepest slope at 25 deg. When we compared the measurement result of the lens mold to a commercial surface profiler, we found that the accuracy of the developed system was less than 90 nm (in terms of 3 sigmas of error) between the two results.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.1080-1083
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• 2002

In this paper, we have studied with regard to the use of lasers for modifying the surface properties of silicon in order to improve it's wettability and adhesion characteristics. Using an Nd:YAG pulse laser, the wettability and adhesion characteristics of silicon surface have been developed by an Nd:YAG pulse laser. It was found that the laser treatment of silicon surfaces modified the surface energy. In the result of wetting experiments, by the sessile drop technique using the distilled water, wetting characteristic of silicon after the laser irradiation shows a decreased value of the contact angle. In case of the laser treated silicon surface, laser direct writing of copper lines has been achieved by pyrolytic decomposition of copper formate films$(Cu(HCOO)_2{\cdot}4H_2Q)$, using a focused $Ar^+$ laser beam$(\lambda=514.5nm)$ on the silicon substrates. The deposited patterns were measured by energy dispersive X-ray(EDX), Scanning Electron Microscopy(SEM) and surface profiler($\alpha$-step) to examine the cross section of deposited copper lines and linewidth.