• Journal of the Korean Ceramic Society
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• v.39 no.11
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• pp.1035-1041
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• 2002

The adhesion characteristics of adsorbent during impregnation of Y-type and ZSM-5type zeolites into ceramic paper were analyzed, as the amount of silica sol in slurry for impregnation was varied. 31 wt% of zeolite particle, which is useful for VOC adsorption, was evenly dispersed and adhered on ceramic paper and original crystal structure of the zeolite remained unchanged even after binder application and heat treatment. Surface area of the impregnated ceramic paper was decreased compared with that of zeolite powder. And it was found to be attributed to the reduction of volume of mesopore while the volume of micropore under $20{\AA}$ was unchanged. Zeolite-impregnated honeycomb cylinder, whose diameter and length were 10 cm and 40 cm, respectively, was subjected to adsorption/desorption test with respect to toluene, MEK, cyclohexanone. All of the VOC's were removed by adsorption with efficiency higher than 97% and from the static adsorption test, $42 Nm^3/h$ of 300 ppmv-VOC-laden air was calculated be treated continuously, when the honeycomb was used in an adsorptive rotor system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.343-343
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• 2008

Newly designed structure of a thin ultrasonic rotary motor was proposed. Thin brass plate was used as a cross shaped vibrator and eight ceramic plates were attached on the upper and bottom sides of the brass plate as in Figure 1. The thin type ultrasonic motor has the structure adherent piezoelectric ceramic on the top and bottom surface of the thin elastic body. The direction of polarization is decided so as to occur the elliptical displacement in regular sequence at touch point A, B, C and D of stator contacted with rotor. By applying two electric fields which have 90 degree phase difference on the ceramics, each contact points make rotational displacements as in figure 2. Finite element analysis program ATILA was used to find the optimal size of the stator. As a result of the simulation, elliptical displacements of the tips were obtained at off-resonance frequencies. The maximum displacements of the contact tips were obtained at the length of 16[mm], width of 6[mm] and thickness of 0.4[mm]. Changes of the resonance frequencies were inversely proportional to the length of ceramic and proportional to the width of ceramic. Elliptical motions of the contact tips. of the stator were consistently obtained at off resonance frequencies. From a prototype motor, speed of 600[rpm] was obtained at 20[Vrms].

• Advances in aircraft and spacecraft science
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• v.10 no.1
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• pp.19-49
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• 2023

The present study proposes a theoretical and numerical investigation on the dynamic response behaviour of a functional graded (FG) ceramic-metal tapered rotor shaft system, by the differential quadrature finite elements method (DQFEM) to identify the natural frequencies for modelling and analysis of the structure with suitable validations. The purpose of this paper is to explore the influence of heat gradients on the natural frequency of rotation of FG shafts via three-dimensional solid elements, as well as a theoretical examination using the Timoshenko beam mode, which took into account the gyroscopic effect and rotational inertia. The functionally graded material's distribution is described by two distribution laws: the power law and the exponential law. To simulate varied thermal conditions, radial temperature distributions are obtained using the nonlinear temperature distribution (NLTD) and exponential temperature distribution (ETD) approaches. This work deals with the results of the effect on the fundamental frequencies of different material's laws gradation and temperature gradients distributions. Attempts are conducted to identify adequate explanations for the behaviours based on material characteristics. The effect of taper angle and material distribution on the dynamic behaviour of the FG conical rotor system is discussed.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1780-1782
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• 1999

The ultrasonic motor used here is the windmill type ultrasonic motor operated by single-phase AC source. A metal-ceramic composite component was used as the stator element to generate ultrasonic vibrations. The windmill type ultrasonic motors has only three components; a stator element of two wind-mill shape slotted metal endcaps, a rotor and a bearing. In this paper we proposed a system for torque measurement of piezoelectric ultrasonic motor.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2002.11a
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• pp.209-214
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• 2002

냉방과 습기제거에 제습제를 이용하는 것은 효과적이고, 경제적이며 환경 친화적인 방법이다. 제습제를 사용한 공기조화시스템은 학교, 극장, 슈퍼마켓, 병원과 음식점 등 모든 건물에 신선한 공기를 제공함으로써 실내공기의 품질을 향상시킨다. 수분을 포함하는 다량의 공기를 제습하기 위해서는 제습제와 공기의 접촉을 늘려주어야 하고, 이를 위하여 허니컴 형태의 제습제를 사용하는 것이 바람직하다.(중략)

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2002.05a
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• pp.155-160
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• 2002

최근 들어서 오존층을 파괴하는 것으로 알려진 CFC와 같은 냉매를 사용하지 않고 허니컴식 제습rotor와 rotor식 현열교환기로 구성된 '흡착식제습냉난방시스템'이 개발되어 실용화 단계에 있다. 제습제를 이용한 냉방시스템은 에너지측면에서 효율적이고, 비용 면에서 경제적이며, 환경친화적이다.(중략)

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2000.11a
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• pp.205-210
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• 2000

VOC는 volatile organic compound의 약자로서 toluene, benzene, MEK, MIBK등 자동차 운행, 도장산업, 인쇄업, 대형 세탁시설, 유류저장 및 출하시설에서 주로 배출되는 유기성 배기배출물을 총칭하는 개념이다. VOC는 작업현장에서 악취를 발생시켜 작업현장에서의 쾌적성을 해치기도 하지만, 태양에너지를 받아 오존을 형성하기 때문에 인체에 크게 해로운 역할을 한다. 정부에서는 대기환경보전법을 제정하여 휘발성유기화합물질 배출억제 정책을 실시하고 있으며, 배출업소에 대하여 휘발성유기화합물질 방지시설 설치를 의무화하고 있다.(중략)

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.03a
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• pp.2-4
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• 2010

Nowadays, application fields using piezoelectric ceramics are various. On this paper, Characteristics of thin-type ultrasonic motor generating elliptical displacements has been analyzed by FEM, and then the motor was fabricated. Structure of the motor consists of sixteen ceramic pieces attached elastic body upper and bottom. Principle of the motor is to apply alternative voltages which have 90 phase difference to attached ceramics, and then elliptical displacements is generated at four edges of clastic body. And then rotor is rotated by the elliptical displacements. In case of ceramic thickness 1.5[mm], characteristic of the highest speed was found at 79[kHz]. In case of ceramic thickness 2[mm], Characteristic of the highest speed was observed at 77.5 [kHz]. Consequently, speed and torque of USM were increased linearly with increasing in applied voltage.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.7
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• pp.525-529
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• 2010

In this paper, the characteristics of a thin-type ultrasonic motor generating elliptical displacements analyzed by FEM are presented, and then fabrication of the motor is then described. The structure of the motor consists of sixteen ceramic pieces attached to the upper and bottom surfaces of an elastic body. The principle of the motor is to apply alternating voltages which have a 90 phase difference to the attached ceramics, and then elliptical displacements are generated at four edges of the elastic body. Then the rotor is moved by the elliptical displacements. In the case of a ceramic thickness of 1.5, the highest speed was obtained at 79 kHz. In the case of a ceramic thickness of 2 mm, the highest speed was obtained at 77.5 kHz. Consequently, the speed and torque of the ultrasonic motor (USM) increased linearly with increasing applied voltage.

• Journal of the Korean Ceramic Society
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• v.39 no.11
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• pp.1042-1047
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• 2002

The sedimentation characteristics of ceramic fiber were analyzed when viscosity of the slurry for ceramic paper formation was varied and zeta potential change and degree of dispersion with pH were studied as well. The proper viscosity of the slurry for dispersion of fibers was between 28 and 31 cps. Zeta potential of the slurry was sensitively changed with pH adjustment and showed maximum value of -35~-36 mV at ph 7.5~9.5, which indicated better dispersion of ceramic fiber as zeta potential of the slurry was increased. The sedimentation rate of ceramic fiber in a slurry was reported minimum at the maximum zeta potential. Water content of the casted paper should be lower than 83% after vacuum dehydration for retention of binder and lower than 62% after press rolling for wet paper handling. The obtained ceramic paper had tensile strength and basis weight, $102 kgf/cm^2$ and $98 g/m^2$, respectively.