• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1993년도 추계학술대회 논문집
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• pp.475-481
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• 1993

The objective of this study is to develope the reliability prediction model for Float Rated Integrating Gyroscope( :FRIG) at maximum loading. The equation of motion for FRIG is firstly derived to set up the reliability prediction model. To analysis reliability or all parts of the gyro is not easy due to their complicated structure. Therefore the failure parts are chosen by Failure Mode Effective Analysis (:FMEA). F.E.M is utilized to calculate loads for the selseced rotating assembly and pivot / jewel. The technical reliability is calculated by applying reliability design theory with these results and the performance reliability is sought through distribution estimation with error test data. The bulk reliability of gyroscope is sought by applying the two results. The present prediction results are compared with the accumulation time in good agreement.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2009년도 학술발표회 초록집
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• pp.410-414
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• 2009

홍수 유량 측정에 주로 활용되는 봉부자법은 신속하고 간편하게 유량을 측정할 수 있지만, 부자의 유하 경로를 정확하게 알 수 없으므로 가정된 직선을 따라 유하하지 않을 경우 유속과 단면적 계산에 불확실성이 다소 크게 발생하는 단점이 있다. 또한 측정에 소요되는 시간이 짧지만, 대개 현장에서 유량 계산이 바로 이루어지지 못하므로 측정 유량의 적절성을 충분히 평가하지 못한다. 본 연구에서는 봉부자법의 장점은 살리고 단점을 개선할 수 있는 전자부자 시스템을 개발하고 이를 이용하여 유량을 산정하였다. 개발된 전자부자 시스템은 GPS에 의해 유하경로를 획득하여 RF 통신을 통해 실시간으로 기지국에 정보를 전송한다. 기지국은 3개 RF 채널을 통해 최대 15개의 전자부자의 위치 정보를 동시에 수집하며, 각 전자부자의 유하경로와 미리 측량한 단면 자료를 결합하여 측정과 동시에 자동으로 유속을 계산한다. 이렇게 계산된 유속은 지리정보와 결합되어 있으므로 하천의 평면 2차원적 흐름 특성을 나타내는데 활용될 수 있으며, 나아가 미리 측량된 단면 자료와 결합하여 측정과 동시에 즉각 유량이 얻어질 수 있다. 이러한 점에서 본 연구는 전자부자를 이용하여 현장에서 유속과 유량을 실측한 사례를 제시하고자 한다.

• Macromolecular Research
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• 제12권2호
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• pp.189-194
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• 2004

When water is evaporated quickly from a water-based colloidal suspension, colloidal particles protrude from the water surface, distorting it and generating lateral capillary forces between the colloidal particles. The protruded colloidal particles are then assembled into ordered colloidal crystalline domains that float on the water surface on account of their having a lower effective density than water. These colloidal crystal domains then assemble together by lateral capillary force and convective flow; the generated colloidal crystal has grain boundaries. The single domain size of the colloidal crystal could be controlled, to some extent, by changing the rate of water evaporation, but it seems very difficult to fabricate a single crystal over a large area of the water's surface without reorienting each colloidal crystal domain. To reorient such colloidal crystal domains, a glass plate was dipped into the colloidal suspension at a tilted angle because the meniscus (airwaterglass plate interface) is pinned and thinned by further water evaporation. The thinning meniscus generated a shear force and reoriented the colloidal crystalline domains into a single domain.

• 환경위생공학
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• 제15권3호
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• pp.37-43
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• 2000

The purpose of this experimental study examine characteristics of blood pigments removal of butchery wastewater by heat processed eggshell, compare activated carbon with its efficiency. Calcined eggshell were classified into four kinds of mesh as HPES-32(Heat Processed Eggshell 32 $mesh=500{\mu}m$), HPES-48($300{\mu}m$), HPES-150($180{\mu}m$) and HPES-150($106{\mu}m$). And two contacting process of CMFA(Complete Mixing Float Adsorption) and FLFA(Fixing layer Flow Adsorption) Were used for getting removal efficiency of blood pigments. In case of using CMFA process, the removal efficiency of blood pigments was occurred as HPES-80>HPES-150>HPES-32, but in case of using FLFA process was occurred as HPES-150>HPES-80>HPES-48>HPES-32. The two results between CMFA and FLFA were differ in strength of removal efficiency of blood pigments.

• Journal of Mechanical Science and Technology
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• 제18권11호
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• pp.1978-1988
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• 2004

Hybrid finite element analysis was used to analyze the influence of bearing stiffness on the static properties of a planetary gear system with manufacturing errors. The effects of changes in stiffness were similar for most of the manufacturing errors. State variables were most affected by the stiffness of the planet ,bearings. Floating either the sun or carrier helps to equal load sharing and minimizes the critical tooth stress. The effects of a floating sun and carrier are similar, but it is not recommended that both float, because this can induce greater critical tooth stress. Planet bearing stiffness should be optimized. Both load sharing and critical tooth stress should be considered to determine optimal bearing stiffness.

• 한국군사과학기술학회지
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• 제21권4호
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• pp.520-528
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• 2018

This paper studies the optimal inventory levels of Korea Assault Amphibious Vehicle(KAAV)'s assemblies in order to assure the required operational availability. The simulation model is built and implemented for the impact of the inventory levels on operational availability. Using regression analysis and integer programming, the optimal inventory levels of essential assemblies are suggested and analyzed. Finally, sensitivity analysis is conducted with recycling maintenance delay time.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년 학술대회 논문집 정보 및 제어부문
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• pp.244-246
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• 2006

In this study, we search some parameters well-related to floating-sinking pulse by statistical analysis, because these pulses are frequently used in clinic. Pulse signals were acquired by 3D pulse analyzer and 30 subjects consist of 15 people diagnosed as floating pulse and 15 people diagnosed as sinking pulse by oriental doctors who have over 5 years clinical experience. Then, we made a representative beat template for each subject and, through a peak detection algorithm, we calculated several pulse parameters. To find the parameters related to floating-sinking pulse, we performed statistical testing with 17 parameters through the independence sampling, t-test. As a result, there is the biggest difference between pressure, the maximum pulse pressure, diastolic area(Ad) and float-sink data. (p < .05).

• 한국세라믹학회지
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• 제52권6호
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• pp.403-409
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• 2015

Porous alumina ceramics are involved in many industrial applications due to the exceptional properties of these products. This study addresses the preparation of porous alumina ceramics using hollow microspheres as a pore-forming agent and slip casting as a green-body-forming technique. A uniform distribution of pores is a basic requirement of a porous material. This study investigates three different slurry systems, i.e., as-prepared alumina slurry, alumina slurry electrostatically dispersed by hydrochloric acid (HCl), and slurry dispersed by the commercial dispersant 'Darvan C-N'. At a low viscosity, the hollow microspheres in the slurry tend to float, which causes a non-uniform pore distribution. To avoid this phenomenon, the viscosity of the slurry was increased to the extent that the movement of hollow microspheres ceased in the slurry. As a result, a uniform pore distribution was achieved.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 F
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• pp.2590-2593
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• 1999

This paper describes the development of Emergency Generator Equipments Diagnosis System for monitoring generator equipments and battery system. This system is capable of measuring on up to 20 separate sites of generator, engine and periphral equipment's. Battery system also capable of measure the setting time, float and discharge voltage of up to 240 cells in a single installation, and has the memory capacity to store battery's alarm data information on up to 200 separate sites. This system are easy to maintain and attain cost effectively, so that prepared for meeting the customer's service needs immediately. The system is additionally programmed with a each model, that will enable to accurately determine the generator equipments and remain battery capacity in a system following a short discharge test. It is also equipped with remote interrogation and control facilities.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2003년도 The Fifth Asian Computational Fluid Dynamics Conference
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• pp.160-161
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• 2003

Thermocapillary convection is a surface tension driven flow due to a temperature gradient along an interface. It occurs during a crystal-growth process and therefore understanding the convection is important to material processing in microgravity. Although modelling of the float-zone crystal-growth process has been of interest for a few decades, most studies of liquid bridges assumed non-deformable flat surfaces. In reality, the surface profile, g(t,z), is unknown and should be obtained as a solution to the coupled transport equations along with the surface force balance. Here we report on a numerical study of axisymmetric thermocapillary convection in liquid bridges with deformable surfaces. The interface is determined as part of the complete solution. The influence of the capillary number (Ca), Reynolds number (Re), Prandtl number (Pr) and aspect ratio(Ar) on the dynamics is explored.