• 한국정밀공학회지
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• 제17권5호
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• pp.124-130
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• 2000

For measuring out the submicron order straightness, a precision measuring device is developed in this paper. The device is constructed with a hydrostatic feed table and a capacitive type sensor which is mounted to the feed table. Straightness is acquired as substracting the motion error of feed table from the measured profile with probe. Motion error of feed table is simultaneously compensated upto 0.120${\mu}{\textrm}{m}$ of linear motion error and 0.20arcsec of angular motion error using the active controlled capillary. Reversal method and strai호t-edge is used fur estimating the measuring accuracy and from the experimental result, it is verified that the device has the measuring accuracy 0.030m. Also, through the practical application on the measurement of ground surface, it is confirmed that the device is very effective to measure the submicron order straightness.

• 한국자동차공학회논문집
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• 제7권5호
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• pp.9-15
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• 1999

A digital CDI(Capacitive Discharge Ignition) system on small two stroke motorcycle engine was developed in this paper, This CDI system with microprocessor as its main part has more flexible spark timing than the conventional CDI system because of its programmable characteristics. The principle of this digital CDI system and the design methods of hardware and software were presented in this paper, Two stroke small engine was tested to investigate the performance of digital CDI system And also this system was investigated to optimize the engine performance. Also comparison between conventional CDI can provide better spark timing variation than the conventional system. The part and full load test results show that the engine power was increased about 10-20% and fuel consumption was decreased about 10-20% simultaneously. Furthermore, this digital CDI system has simple structure, low cost and very little modification are required. It is a promising technology to substitute for the widely used conventional CDI system.

• 한국공작기계학회논문집
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• 제16권6호
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• pp.140-145
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• 2007

To improve productivity of a metal cutting process, it is required to monitor machining stability in real time. Since cutting environment is harsh against sensing conditions due to vibration, chip, and cutting fluid, etc., it is necessary to develop a robust and reliable sensing system for the practical application. In this work, a chatter monitoring system was developed and its effectiveness was proved. Spindle displacement caused by cutting was selected as a main monitoring parameter. A cylindrical capacitive displacement sensor was adopted. Chatter frequencies were identified through modal analysis. To quantify chatter vibrations, chatter correlation coefficient was introduced. The identification of the monitoring system showed a good agreement with the result of experiment.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 C
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• pp.1529-1531
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• 2003

Thick film mechanical sensors can be categorized into four main areas piezoresistive, piezoelectric, piezocapastive and mechanic tube. In this areas, the thick film strain gage is the earliest example of a primary sensing element based on the substrates. The latest thick film sensor is used various pastes that have been specifically developed for pressure sensor application. The screen printing technique has been used to fabricate the pressure sensors on alumina substrate($Al_2O_3$). Thick film capacitive of strain sensing characteristics are reported and dielectric paste based on (Ti+Ba) materials. The electric property of dielectric paste has been studied and exhibit good properly with good gage factor comparable to piezoresistive strain gage. New piezocapacitive strain sensor was designed and tested. The output of capacitive value was good characteristics.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집C
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• pp.53-58
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• 2001

This paper presents a high resolution capacitive microaccelerometer for applications to personal information systems. We reduce the mechanical noise level of the microaccelerometer by increasing the proof-mass based on deep RIE process. We reduce the electrical noise level by increasing the amplitude of an AC sense voltage. The high sense voltage is obtained by DC-to-DC voltage multiplier. In order to solve the nonlinearity problem caused by the high sense voltage, we modify the conventional comb electrode of straight finger type into that of branched finger type, resulting in self force-balancing effects for enhanced detection linearity. The proposed branched finger capacitive microaccelerometer was fabricated by the deep RIE process of an SOI wafer. The fabricated microaccelerometer reduces the electrical noise at the level of $2.4{\mu}g/\sqrt{Hz}$ for the sense voltage of l6.5V, which is 10.1 times smaller than the electrical noise level of $24.3{\mu}g/\sqrt{Hz}$ at 0.9V. For the sense voltage higher than 2V, the electrical noise level of the microaccelerometer became smaller than the constant mechanical noise level of $11{\mu}g/\sqrt{Hz}$. Total noise level, including the electrical noise and the mechanical noise, has been measured as $9{\mu}g/\sqrt{Hz}$ for the sense voltage of 16.5V, which is 3.2 times smaller than the total noise of $28.6{\mu}g/\sqrt{Hz}$ for the sense voltage of 0.9V. The self force-balancing effect results in the increased stiffness of 1.98 N/m at the sense voltage of 17.8V, compared to the stiffness of 1.35 N/m at 0V, thereby generating the additional stiffness at the rate of $0.002N/m/V^{2}$.

• 비파괴검사학회지
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• 제33권1호
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• pp.14-19
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• 2013

금속 재료의 비선형 파라미터는 고유한 물성치로서 기본주파수의 음압의 크기($A_1$)과 2차고조파의 음압의 크기($A_2$)을 측정하면 산정할 수 있다. 하지만, 실험적으로 $A_1$과 $A_2$를 측정하는 것은 매우 복잡한 변환 과정이 필요하기 때문에 현재 많은 연구자들이 비선형 파라미터의 절대값을 측정하지 않고, 전압 변화를 관찰하는 비선형 파라미터의 상대값을 측정하고 있다. 하지만, 비선형 파라미터 상대값으로는 재료의 물성치를 대변할 수가 없기 때문에, 열화도에 따른 시편 측정에만 사용할 수 있는 제약이 있다. 따라서 본 연구에서는 정전용량 측정기법(capacitive detector)보다는 비용이 적게 소모되고 현장 적용이 가능한 압전형 수신기법(piezoelectric detection)을 이용하여 비선형 파라미터의 절대값을 측정하기 위한 시스템을 구축하였다. $A_1^2vsA_2$ 그래프로 시스템의 선형성을 검증하고 시험편인 fused silica와 Al2024-T4에 대한 비선형 파라미터를 측정하였다.

• 멤브레인
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• 제27권2호
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• pp.129-137
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• 2017

본 연구에서는 수계 내 포함된 양이온들 중 특히 중금속 이온을 효율적으로 분리할 수 있는 양이온 교환막을 개발하였다. 기저 고분자로는 sulfonated polyetheretherketone (SPEEK)를 사용하였으며 이에 중금속 이온에 결합력이 강한 킬레이팅 수지를 파우더링하여 첨가하였다. 또한 양이온 교환막의 성능을 최적화시키기 위해 킬레이팅 수지의 함량 및 SPEEK의 이온교환용량을 제어하였다. 결과적으로 제조된 양이온 교환막을 막 축전식 탈염 공정(membrane capacitive deionization, MCDI)에 적용한 결과 중금속 이온 제거 효율이 20% 이상 향상됨을 확인할 수 있었다.

• 멤브레인
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• 제26권3호
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• pp.229-237
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• 2016

막결합 축전식 탈염에 적용하기 위하여 불균질 이온교환막을 제조하였다. 이온교환수지 분말과 LLDPE (linear low density polyethylene) 혼합물을 압착시켜 불균질 이온교환막을 제조하였다. 제조한 막의 막 특성 분석과 MCDI 탈염실험을 실시하였다. 이온교환수지의 함량이 증가할수록 막의 전기저항은 감소하였고 함수율은 증가하였다. 그러나 막의 이온선택성을 나타내는 이온 수송수는 상업용 균질 막과 유사한 성능을 나타냈다. MCDI 탈염실험 결과 탈염량은 불균질 막의 높은 전기저항으로 인해 균질 막을 이용한 셀의 탈염량의 90% 수준을 나타냈다. 불균질 이온교환막은 균질 막에 비해 탈염성능은 다소 감소하였지만 제조가 간편하고 가격이 저렴하여 MCDI에 적용이 가능할 것으로 판단되었다.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제6권4호
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• pp.304-313
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• 2006

This paper describes a novel way of applying capacitive sensing technology to a mobile user interface. The key idea is to use grip-pattern, which is naturally produced when a user tries to use the mobile device, as a clue to determine an application to be launched. To this end, a capacitive touch sensing system is carefully designed and installed underneath the housing of the mobile device to capture the information of the user's grip-pattern. The captured data is then recognized by dedicated recognition algorithms. The feasibility of the proposed user interface system is thoroughly evaluated with various recognition tests.

• 항공우주시스템공학회지
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• 제12권6호
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• pp.17-22
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• 2018

항공기 항속시간에 영향을 미치는 요소인 연료량은 정확한 측정이 필요하다. 본 논문에서는 정전용량형 연료센서, DAQ 보드, Labview 소프트웨어로 구현된 연료량측정시스템을 다루었다. 연료량에 따라 변화하는 파라미터를 확인하기 위해 Pspice를 이용하여 구현된 시스템의 주회로가 시뮬레이션 되었다. 시뮬레이션을 통해 연료량에 따라 변화하는 파라미터인 Vrms를 찾아내었다. 연료 센서의 출력인 Vrms는 구현된 연료량측정시스템의 DAQ 보드를 통해 Labview 소프트웨어로 전송되고, 이 소프트웨어를 사용하여 연료량이 계산된다. 그 결과, 필터가 적용되지 않은 연료량측정시스템보다 정확도가 향상되었다.