• 대한기계학회논문집B
• /
• 제32권7호
• /
• pp.487-496
• /
• 2008

Quartz crystal oscillator is frequently used in measuring a very small amount of mass attached to or adsorbed on the surface of an electrode on the quartz plate. The physical principle is that the resonance frequency of the shear vibration of the quartz caused by an applied electric field is a function of the mass. Recently, effort has been tried to measure physical properties of viscoelastic fluids, such as viscosity and shear modulus. This paper presents useful formula that can be used in estimating the properties of viscoelastic fluids. Important finding in this analysis is that the formula can produce multiple values for the physical properties of the viscoelastic materials.

• Applied Science and Convergence Technology
• /
• 제25권6호
• /
• pp.124-127
• /
• 2016

Humidity calibration for a temperature-stable quartz oscillator (TSQO) was investigated to exclude the influences of relative humidity on the TSQO output in order to use the corresponding devices outdoors. The TSQO output is a voltage that is inversely proportional to the electric impedance of the quartz oscillator, which depends on the viscosity and density of the measured gas. The TSQO output was humidity calibrated using its humidity dependence, which was obtained by varying the relative humidity (RH) from 0 to 100 RH% while other conditions were kept constant. The humidity dependencies of the TSQO output were fit by a linear function. Subtracting the change in the TSQO output induced by the change in humidity, calculated with the function from the experimentally measured TSQO output for a range of 0-100RH%, eliminated the influence of humidity on the TSQO output. The humidity calibration succeeded in reducing the fluctuations of the TSQO output from 0.4-3% to 0.1-0.3% of the average values for a range of 0-100RH%, at constant temperatures. The necessary stability of the TSQO output for application in hydrogen sensors was below one-third of the change observed for a hydrogen leakage of 1 vol.% hydrogen concentration, corresponding to 0.33% of the change in each background. Therefore, the results in this study indicate that the present humidity calibration effectively suppresses the influence of humidity, for the TSQO output for use as an outdoor hydrogen sensor.

• 대한전자공학회논문지
• /
• 제6권4호
• /
• pp.20-30
• /
• 1969

전압 가변용량 다이오드를 사용하여서 인가전압을 변조신호로 하였을때 수정발진회로의 동조소자로 하면 변조입력을 전혀 필요지 않는 진폭변조방식을 실현할 수 있으며 한편에서는 수정발진자를 4분지 1파장 결합회로를 통하면 하아트레 발진회로가 가장 광대역 주파수 변조기로서 적합함을 시작 결과로서 입증하였다.

• Bulletin of the Korean Chemical Society
• /
• 제17권1호
• /
• pp.39-42
• /
• 1996

A new oscillator for electrochemical quartz crystal microbalance (EQCM) was developed by using an operational amplifier without any LC component. The home-made EQCM using this oscillator showed only 0.02 Hz frequency noise at 0.3 s gate time when a 6 MHz AT-cut crystal was used. Pb underpotential deposition on gold substrate in nitric acid media was examined to demonstrate the performance of this EQCM. The derivative of frequency change could be obtained without averaging multiple scans.

• 센서학회지
• /
• 제19권2호
• /
• pp.149-154
• /
• 2010

Top of the alumina body which is made according to plan has been printed using a screen printer equipment in order to print an electrode pattern. The electrode is connected with the quartz crystal oscillator of the piezoelectricity method which has a piezoelectric characteristic. The pressure contact department has been experimented using three type of the teflon. The teflon is good for pressure delivery vector but it is bad restitution. So we devised the structure which inserts the metal in the teflon. Bottom of the module is connected with the signal processing department which is planned in advance and then has investigated to characteristic. Therefore we have got the best output-voltage and frequency characteristic follows in the pressure.

• 한국광학회지
• /
• 제10권4호
• /
• pp.267-272
• /
• 1999

근접장광학계 (Near-Field Scanning Optical Microscope :NSOM)의 표본과 팁의 거리 유지를 위해 소리굽쇠모양의 수정발진자 (tuning forktype quartz crystal unit)의 한쪽 다리에 광섬유를 고정시키고 광섬유 팁을 수정발진자와 같이 진동하게 만들어 사용하였다. 수정 진동자는 광섬유 팁이 시료에 얼마나 가까이 갔느냐에 따라 진폭이 바뀌게 되고 이 변화를 일반적인 방법인 레이저 빛에 의하여 읽어내는 것이 아니라 바로 수정 발진자의 임피던스 변화에 따른 전압 변화를 측정하여 알아냈다. 팁이 표면에 접근함에 따라 수정발진자 진동폭의 변화와 팁을 통해 들어오는 빛의 세기 변화 등을 측정하여 계의 감도를 조사하였다.

• 대한전자공학회논문지
• /
• 제8권5호
• /
• pp.27-39
• /
• 1971

이동편 간이형 FM송신기를 제작할때 종전방식에 의한 리액턴스변조방식보다 VVC다이오드를 사용한 수정주파수변조방식이 채배단을 필요치않기 때문에 변조기로서 더 적합하다. 이때 수정발진자와 변조회로소자 및 VVC다이오드와의 관계에서 가장 변조직선성이 좋으면서 중심주파수의 안전도를 허용범위내에 들게하려면 어떻게 하면 되는가를 이론적해석과 실험적결과로서 입증하였다.

• 한국정보기술응용학회:학술대회논문집
• /
• 한국정보기술응용학회 2005년도 6th 2005 International Conference on Computers, Communications and System
• /
• pp.103-106
• /
• 2005

This paper reports design and fabrication of CMOS temperature sensor circuit using MOSIS 0.25um CMOS technology. The proposed circuit has a temperature coefficient of $13mV/^{\circ}C$ for a wide operating temperature range with a good linearity. This circuit may be applicable to the design of one-chip IC where quartz crystal resonator is directly mounted on CMOS oscillator chips.

• Bulletin of the Korean Chemical Society
• /
• 제17권11호
• /
• pp.975-977
• /
• 1996

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 C
• /
• pp.434-436
• /
• 2000

In this study, we investigate the optical characteristics of merocyanine dye Langmuir-Blodgett(LB) film using the oscillation characteristics of quartz crystal. As results, the resistance and frequency shift at the parallel resonance under the UV irradiation is to be going down. This behaviour of resistance and frequency is different from the case of general mass adsorption into the organic film on the quartz crystal. Generally the frequency decrease of quartz crystal oscillator, which has been considered as mass loading, goes along with the resistance increase. Thus it has been suggested that the J-aggregate dissociation in merocyanine dye LB film by UV irradiation give rise to transformation of oscillation characteristics of quartz crystal.