• 융합신호처리학회논문지
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• 제8권1호
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• pp.73-77
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• 2007

본 논문에서는 적응 필터링 분야에서 널리 쓰이고 있는 재귀형 LMS 필터의 고속연산을 위해 Cyclo-static 스케줄러를 이용하여 VLSI구현에 적합한 구조를 제안한다. 이과정은 크게 스케줄 생성 단계와 회로도 생성 단계로 구성되는데, 스케줄 생성단계는 입력으로서 Fully Specified Flow Graph(FSFG)로 표현된 재귀 DSP 알고리듬을 취하여 입력의 샘플링속도, 프로세서의 수, 그리고 주어진 입력에 대한 출력의 지연에 있어 최적인 Cyclo-static 스케줄러를 생성하여 각 프로세서간의 연결선이 최소가 되도록 스케줄을 변환한다. 회로도 생성 단계에서는 이 변환된 스케줄러로부터 미리 정의된 두 가지 형태의 프로세서 구조를 이용하여 그것을 구성하고 있는 레지스터 및 멀티플렉서의 할당을 행하고 제어신호를 포함한 완전한 회로도를 생성한다, 이렇게 생성된 회로도는 기존의 실리콘 컴파일러를 이용하여 VLSI 레이아웃으로 용이하게 변환 될 수 있다.

• Journal of Advanced Marine Engineering and Technology
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• 제27권6호
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• pp.753-758
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• 2003

In this study. an experiment has been performed to investigate distributions of static pressure around a circular cylinder in a uniform shear flow which is made by a specially designed wind tunnel. From the computation program(BLAYER), various boundary layer value are obtained depending on the shear flow rate. It is basical design data that boundary layer flow phenomenon of nuclear power plant heat exchanger tube surroundings. airfoil. and others flow fields.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.157-164
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• 2008

The temperature-entropy diagram of water or vapor displays graphically the thermophysical properties, so it is very conveniently used in various thermal systems. On general T-s chart of water, there are temperature, pressure, quality, specific volume, specific enthalpy, specific entropy. However, various state and process values besides above properties can be plotted on T-s diagram. In this study, we developed the software drawing twenty six kinds of properties, that is temperature, pressure, quality, specific volume, specific internal energy, specific enthalpy, specific entropy, specific exergy, exergy ratio, density, isobaric specific heat, isochoric specific heat, ratio of specific heat, coefficient of viscosity, kinematic coefficient of viscosity, thermal conductivity, prandtl number, ion product, static dielectric constant, isentropic exponent, velocity of sound, joule-thomson coefficient, pressure coefficient, volumetric coefficient of expansion, isentropic compressibility, and isothermal compressibility. Also, this software can analyze and print the system values of mass flow rate, volume flow rate, internal energy flow rate, enthalpy flow rate, entropy flow rate, exergy flow rate, heat flow rate, power output, power efficiency, and reversible work. Additionally, this software support the functions such as MS-Power Point.

• 대한기계학회논문집A
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• 제31권2호
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• pp.174-181
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• 2007

This paper is concerned with the thermo-mechanical behavior of steel sheet for an auto-body including temperature dependent strain rate sensitivity. In order to identify the temperature-dependent strain rate sensitivity of SPRC35R, SPRC45E and TRIP60, uniaxial tensile tests are performed with the variation of the strain rates from 0.001/sec to 200/sec and the variation of environmental temperatures from $-40^{\circ}C$ to $200^{\circ}C$. The thermo-mechanical response at the quasi-static state is obtained from the static tensile test and that at the intermediate strain rate is obtained from the high speed tensile test. Experimental results show that the variation of the flow stress and fracture elongation becomes sensitive to the temperature as the strain rate increases. It is observed that the dynamic strain aging occurs with TRIP60 at the temperature above $150^{\circ}C$. Results also indicate that the flow stress and tincture elongation of SPRC35R are more dependent on the changes of strain rates and temperature than those of SPRC45E and TRIP60.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 춘계학술대회논문집
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• pp.135-139
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• 1999

The static softening behavior of AISI 4140 could be characterized by the hot torsion test in the temperature ranges of 10$0^{\circ}C$~120$0^{\circ}C$ and strain rate ranges of 0.05/sec~5/sec. Deformation efficiency which was based on dynamic materials model was calculated from flow stress curves obtained continuous deformation. Interrupted deformation was performed with 2 pass deformation in the pass strain ranges of 0.25{{{{ epsilon _p}}}} ~3{{{{ epsilon _p}}}} and interrupted time ranges of 0.5~100sec. The dependences of process variables pass strain ({{{{ epsilon _i}}}}) stain rate ({{{{ {. } atop {$\varepsilon$ } }}}}) temperature (T) and interpass time ({{{{ {t }_{i } }}}}) on static recrystallization (SRX) and metadynamic recrystallization .(MDRX) could be indicidually predicted from the modified Avrami's equations. Comparison of the softening kinetics between MDRX and SRX showed that the rate of MDRX was more rapid than that of SRX for the same deformation variables. Controlled multipass deformations were performed using deformation efficiency static and metadynamic recrystallization of AISI 4140.

• 한국응용과학기술학회지
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• 제28권2호
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• pp.178-184
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• 2011

The analysis of reaction kinetics provided that the reaction order was the $1^{st}$ of triglyceride and the rate constant was 0.067 $min^{-1}$. The transesterification of camelina oil using 0.6 wt% mixed catalyst which consists of 40 v/v% of potassium hydroxide (1 wt%) and 60 v/v% of tetra methyl ammonium hydroxide (0.8 wt%), was carried out at $65^{\circ}C$ on the tubular reactor packed with static mixer. The conversion was shown to be 95.5% at the 6:1 molar ratio of methanol to oil, flow rate of feed of 3.0 mL/min and 24 of element of static mixer. The volume of washing water emitted by 0.6 wt% mixed catalyst was the half of the volume emitted by 1 wt% potassium hydroxide.

• Nuclear Engineering and Technology
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• 제52권2호
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• pp.271-278
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• 2020

The investigation into a full-scale 27 m high, by 6 m wide, thermosyphon loop. The simulation model is based on a one-dimensional axially-symmetrical control volume approach, where the loop is divided into a series of discreet control volumes. The three conservation equations, namely, mass, momentum and energy, were applied to these control volumes and solved with an explicit numerical method. The flow is assumed to be quasi-static, implying that the mass-flow rate changes over time. However, at any instant in time the mass-flow rate is constant around the loop. The boussinesq approximation was invoked, and a reasonable correlation between the experimental and theoretical results was obtained. Experimental results are presented and the flow regimes of the working fluid inside the loop identified. The results indicate that a series of such thermosyphon loops can be used as a cavity cooling system and that the one-dimensional theoretical model can predict the internal temperature and mass-flow rate of the thermosyphon loop.

• 대한기계학회논문집
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• 제19권9호
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• pp.2261-2270
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• 1995

Flow patterns were measured in an unshrouded centrifugal impeller. The flow rate in measurements was fixed at the value corresponding to a nearly zero incidence at the blade inlet. By using a single slanted hot-wire probe and a Kiel probe mounted on the impeller hub disk, the 3-D relative velocities and the rotary stagnation pressures were measured in seven circumferential planes from the inlet to the outlet of the impeller rotating at 700rpm, which diameter is 0.39 meter, and the static pressures and the slip factor at the impeller outlet were calculated from the measured values. From the measured data, the primary/secondary flows, the leakage flows, the wake-jet flows, static pressure distribution on blade surfaces and the wake production mechanism in the impeller passage were investigated.

• Corrosion Science and Technology
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• 제19권6호
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• pp.288-295
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• 2020

This study investigated the erosion-corrosion characteristics of 5038-H321 aluminum alloy in a natural seawater solution through various electrochemical experiments and flow rate parameters. Cathodic polarization experiments were conducted at flow rates ranging from 4 to 12 knots. Considering the concentration polarization section representing a relatively low current density, the range of the potentiostatic experiment was determined to be -1.6 to -1.0 V. The potentiostatic experiment was conducted at various potentials for 180 minutes in seawater. After the experiment, the corrosion characteristics were evaluated by observing surface morphology and measuring surface roughness. As a result, as the applied potential was lower, the amount of calcareous deposits increased and the roughness tended to increase. On the other hand, it was confirmed that the roughness was larger in the static condition than the flow rate condition due to the influence of the flow velocity. Variations in the chemical composition with flow rate variations were analyzed by energy-dispersive spectroscopy (EDS). In conclusion, the cathodic potential of AA5083-H321 in seawater was determined to be -1.0 V.

• 한국자동차공학회논문집
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• 제8권6호
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• pp.9-21
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• 2000

In this study, the characteristics of high-pressure swirl injector have been studied using a commercial CFD code, STAR-CD and experiment to investigate the effect of the length of orifice and swirl port on the spray characteristics. Influences of swirl port angle and initial conditions have also been examined in terms of penetration depth and Sauter`s mean diameter. Computed results of the spray characteristics are compared with experimental results. The results show that the tangential velocity at the nozzle exit decreases, but the axial velocity increases as swirl port angle is increased. Hence, the static flow rate increases, but the initial spray angle decreases with increasing the swirl port angle. It is also shown that the values of the initial SMD used as input data for spray simulation influences the penetration depth and SMD. The spray pattern from the present numerical simulation agrees well with experimental result.