• 공업화학
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• 제16권2호
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• pp.187-193
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• 2005

광촉매 $TiO_2$박막은 titanium (IV) isopropoxide, 에탄올, HCl을 일정한 비율로 졸-겔방법에 의해 제작하였다. SEM에 의한 표면관찰에서는 $500^{\circ}C$에서 5회 반복해서 코팅하여 제작한 것이 우수했다. EDX에 의한 성분비는 spin코팅이 O : Ti의 atom%가 61 : 39로 dip코팅보다 우수했다. 그리고 박막제작의 온도에 따라서 anatase상에서 rutile상으로 결정구조가 변화되어 가는 것을 XRD측정으로 알았다. 제작한 $TiO_2$박막에 UV빔을 조사해서 얻은 TOC의 광분해효율이 1 h 이내에 20~65%를 나타내었고, 그 이후에는 서서히 감소하는 것을 확인했다.

• Journal of Advanced Marine Engineering and Technology
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• 제8권1호
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• pp.85-99
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• 1984

The stability of the two-phase flow in a heated channel is of great importance in the design and operation of the boilers and light water nuclear reactors, because it can cause flow oscillations and lead to a violation of thermal limits with resultant overheating of the channels and cladding. This paper presents a systematic evaluation to the variation effects of the basic four (4) dimensionless parameters in a homogeneous equilibrium model. The flow stability is examined on the ground of static characteristic curves. The complicated transfer function of flow dynamics which gives consideration to the transport lag of density wave is derived, and the transient flow stability is analysed by applying the Nyquist stability criterion in control engineering. The analysis results summed up as follows 1. The coolant flow becomes stable in large friction number and specific flow, while it is unstabale in small friction number and flow. 2. Large phase-change number and Froude number destabilize the two-phase flow, but small numbers stabilize it. The effect to variation of phase-change number is more dominant compared with Froude number. 3. The dynamic analysis is required to hold the sufficient safety of heated channels since only static results does not keep it. The special attention could be payed in the design and operation of heat engines, because the unstaable region exists within the stable boundary at small and middle phase-change number and Froude number.

• 복식
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• 제54권4호
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• pp.85-95
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• 2004

The Purpose of this study was to find a phase of clothing in Korean proverb. The results of the analysis of this research was as follows： In the case of headgear, was expose that symbolize handsomeness, conduct of life, personality that display charm and position which is not usage as only head protection. Upper wear was expressing aspect and person's similarity, and was symbolizing conduct of life by meaning of dress and its ornaments according to a person that dress displays that change. Trousers(bottom wear) was expose that it means aspect or conduct of life(a 4 case, 40％) through site. Overcoat showed that overcoat that is clothes that is symbolizing wearer's situation, aspect and wear most on face because is involved with behavior that is not right in clothes usage is used by standard that foretell personality. Underwear can know that expressed being involved with right behavior, nature by the basic clothes. I was able to know that I express an attitude of a life or a form through shoe, and the accessories won an minor order but that I have a large influence on a character or the appearance of a person. Silk fabrics expresses Position, and hemp cloth expressed by symbol that display ability. Also, silk fabrics had meaning that hint person's background. Dress and its ornaments that is used in proverb by these result can know that have function as symbolic symbol that display Person's nature or situation, aspect that is wearing clothes that is not function as only simple clothes.

• International Journal of Contents
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• 제7권4호
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• pp.98-102
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• 2011

In this study, we investigated the effects of neuromuscular electrical stimulation (NMES) on the treatment of 20 acute stroke patients with dysphagia. For both the treated and control groups, the basic facial stimulation training was conducted for 30 minutes, five times a week, for four weeks. NMES was performed on the treated group only, for 30 minutes each time. Both groups were evaluated according to the functional dysphagia scale (FDS) using a videofluoroscopic swallowing study (VFSS). After the treatment was performed for four weeks, the FDS results of the treated group showed a significance difference in oral transit time in the oral phase and in the triggering of pharyngeal swallow fluid, laryngeal elevation and epiglottic closure, nasal penetration, residue in valleculae, coating of pharyngeal wall after swallow fluid, and pharyngeal transit time in the pharyngeal phase. In addition, the treated group showed a significant difference in laryngeal elevation and epiglottic closure, nasal penetration, and pharyngeal transit time in the pharyngeal phase after the treatment compared to the control group. The results of this study showed that neuromuscular electrical stimulation may be an effective method of treating dysphagia in acute phase stroke patients.

• 한국통신학회논문지
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• 제21권11호
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• pp.2978-2990
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• 1996

With the advent of multimedia era, there are ever increasing interest in computer music and sound syntheis. An FM type sound synthesizing method makes possible the syntheis ofvarious sounds ofmusical instruments with a relatively simple hardware architecture. Therefore, in this paper, we designed a hardware architecture for real-time sound synthesizer and its logic gates. In this paper, we designed a basic sound generator for implementation of real-time logic gates, analzed characteristics of sounds synthesized in this architecture and extracted parameters of FM sounds of musical instruments by using the Csound software. The major bolkcs to build the hardware are a phase-generator, a singe-function-generator, an envelope-generator and a multiplier-part. Finally, logic circuits are designed and verified in VHDL and logic gates by 1.0um standard cell library, which will be easily implementable by the form of ASIC.

• 한국철도학회논문집
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• 제9권3호
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• pp.271-276
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• 2006

Insight into behaviour of pedestrians as welt as tools to assess passenger flow condition is important in such instances as planning and geometric design of railway station under regular and safety-critical circumstances. Algorithm for passenger flow analysis based on DEM (Discrete Element Method) is newly developed. There are lots of similarity between particle-laden two phase flow and passenger flow. The velocity component of 1st phase corresponds to the unit vector of calculation cell, each particle to passenger, volume fraction to population density and the particle velocity to the walking velocity, etc. And, the walking velocity of passenger is also represented by the function of population density. Key algorithms are developed to determine the position of passenger, population density and numbering to each passenger. To verify the effectiveness of new algorithm, passenger flow analysis for the basic models of railway station is conducted.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.387-391
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• 2006

Insight into behaviour of pedestrians as well as tools to assess passenger flow conditions are important in for instance planning and geometric design of railway station under regular and safety-critical circumstances. Algorithm for passenger flow analysis based on DEM(Discrete Element Method) is newly developed. There are lots of similarity between particle-laden two phase flow and passenger flow. The velocity component of 1st phase corresponds to the unit vector of calculation cell, each particle to passenger, volume fraction to population density and the particle velocity to the walking velocity, etc. And, the walking velocity of passenger is also represented by the function of population density. Key algorithms are developed to determine the position of passenger, population density and numbering to each passenger. To verify the effectiveness of new algorithm, passenger flow analysis for the basic models of railway station is conducted.

• 대한임베디드공학회논문지
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• 제18권5호
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• pp.209-215
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• 2023

This study proposes an AC servo motor control program structure and its implementation method to efficiently integrate 13 types of additional compensation algorithms into the basic FOC (field-oriented control) algorithm program. Various compensation algorithms are necessary to enhance the stability and performance of machine tools by compensating for interference from disturbances and vibrations. Each compensation algorithm is implemented as a separate, independent function and called from a switch-case statement in the ISR (interrupt service routine) of the PWM (pulse-width modulation) device. The advantages of this approach include facilitating not only debugging and testing but also reducing the possibility of errors during the program development phase. Thus, it is easy to add and activate each specific compensation algorithm for the program update during the program operation phase. The implemented motor control program was experimented with a single-axis feed shaft testbed driven by a commercial AC servo motor control drive board and a 750 Watts SPMSM (surface-mounted permanent magnet synchronous motor), and the results verified its normal operation and performance improvement.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 춘계학술대회 논문집 에너지변화시스템부문
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• pp.180-182
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• 2009

As a train control system becomes a large scale and complex, it is necessary to control rigorously the system requirements specification of the train control system at the early phase. This paper describes Use Cases and activity diagrams of ATS functions requirements in the train control system. Basic functions of the train control system refers to IEC 62290-land are suggested. And the basic functions includes train operation without a driver. It is anticipated that this paper will be helpful for the analysis of ATS functions, ATO functions and EI function in the train control system.

• 대한기계학회논문집B
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• 제28권1호
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• pp.24-30
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• 2004

Analysis model for the two-phase catalytic reactor is presented. With the progress in development of micro thermofluidic devices, needs fur understanding of the phenomena in two phase reaction in cm scale has been arisen. To investigate thermal and reactive performance of down scaled two phase reactor simple analysis model that is a kind of lumped flow model is proposed. Analysis model presented is based on the experiment on mm scale model reactor. Target experiment is catalytic decomposition of 70wt％ hydrogen peroxide with existence of perovskite L $a_{0.8}$S $r_{0.2}$Co $O_3$ catalyst. It is composed of balance equations of mass and energy. Each phase is considered to be a species fur the simplicity. Axial diffusion and transversal distribution of properties are neglected. Two phase catalytic reaction is modeled as successive gasification of liquid lump around catalyst and reaction in gas phase. Heat transfer is modeled by model function ofNu number. Modeled Nu is expressed as Nu=N $u_{0}$ (1＋ $a_1$( $a_2$ $T^{-}$ $a_3$)exp( $a_4$ $T^{-1}$)exp( $a_{5}$ z). Transfer coefficients are determined by the comparison of experimental results. With the model, heat transfer characteristics are investigated. Also by the mass transfer coefficient, characteristics in mass transfer is investigated. With the result basic understanding on design and analysis of mm scale two-phase reactive device is obtained. Also it can be further applied to micro scale reactive device fabricated by micromachining.ing..