• Title/Summary/Keyword: Non-direct measurement

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A Study on the Fabrication of Laser-Induced Graphene Humidity Sensor for Mounting on a Disposable Mask (일회용 마스크에 장착을 위한 레이저 기반 그래핀 습도센서 제작에 관한 연구)

  • Lee, Jun-Uk;Shin, Yun-Ji;Yang, Hye-Jeong;Shin, Bo-Sung
    • Journal of the Korean Society of Industry Convergence
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    • v.23 no.4_2
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    • pp.693-699
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    • 2020
  • 355nm UV pulse laser is irradiated on the surface of polyimide (PI) by LDW (Laser Direct Writing) method to produce a high sensitivity flexible humidity sensor using a simple one-step process. The LDW method continuously investigates 2-D CAD data using a galvano scanner and an F-lens. This method is non-contact, so it minimizes physical strain on the PI. Laser-induced graphene (LIG) produced by lasers has a high surface area due to its high flexibility and numerous pores and oxidizers compared to conductors. For this reason, it is highly useful as a flexible humidity sensor. The humidity sensor produced in this study was attached to the inside of a mask filter, which has become a hot topic recently, and its applicability was confirmed.The measurement of humidity measured the sensitivity, reactivity, stability and recovery behavior of the sensor by measuring changes in capacitance and resistance.

THE NONDESTRUCTIVE MEASUREMENT OF THE SOLUBLE SOLID AND ACID CONTENTS OF INTACT PEACH USING VIS/NIR TRANSMITTANCE SPECTRA

  • Hwang, I.G.;Noh, S.H.;Lee, H.Y.;Yang, S.B.
    • Proceedings of the Korean Society for Agricultural Machinery Conference
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    • 2000.11b
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    • pp.210-218
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    • 2000
  • Since the SSC(soluble solid contents) and titratable acidity of fruit are highly concerned to the taste, the need for measuring them by non-destructive technology such as NIR(Visual and Near-infrared) spectroscopy is increasing. Specially, in order to grade the quality of each fruit with a sorter at sorting and packing facilities, technologies for online measurement satisfying the tolerance in terms of accuracy and speed should be developed. Many researches have been done to develop devices to measure the internal qualities of fruit such as SSC, titratable acidity, firmness, etc. with the VIS(Visual)/NIR(Near Infrared) reflectance spectra. The distributions of the SSC, titratable acidity, firmness, etc. are different with respect to the position and depth of fruit, and generally the VIS/NIR light can interact with fruit in a few millimeters of pathlength, and it is very difficult to measure the qualities of inner flesh of fruit. Therefore, to measure the average concentrations of each quality factor such as SSC and titratable acidity with the reflectance-type NIR devices, the spectra of fruit at several positions should be measured. Recently, the interest about the transmittance-type VIS/NIR devices is increasing. NIR light can penetrate through the fruit about 1/10-1/1,000,000 %. Therefore, very intensive light source and very sensitive sensor should be adopted to measure the transmitted light spectra of intact fruit. The ultimate purpose of this study was to develop a device to measure the transmitted light spectra of intact fruit such as apple, pear, peach, etc. With the transmittance-type VIS/NIR device, the feasibility of measurement of the SSC and titratable acidity in intact fruit cultivated in Korea was tested. The results are summarized as follows; A simple measurement device which can measure the transmitted light spectra of intact fruit was constructed with sample holder, two 500W-tungsten halogen lamps, a real-time spectrometer having a very sensitive CCD array sensor and optical fiber probe. With the device, it was possible to measure the transmitted light spectra of intact fruit such as apple, pear and peach. Main factors affecting the intensity of transmitted light spectra were the size of sample, the radiation intensity of light source and the integration time of the detector. Sample holder should be designed so that direct light leakage to the probe could be protected. Preprocessing method to the raw spectrum data significantly influenced the performance of the nondestructive measurement of SSC and titratable acidity of intact fruit. Representative results of PLS models in predicting the SSC of peach were SEP of 0.558 Brix% and R2 of 0.819, and those in predicting titratable acidity were SEP of 0.056% and R2 of 0.655.

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Temperature Field and Emission Spectrum Measurement of High Energy Density Steam Plasma Jet for Aluminum Powder Ignition (알루미늄 분말 점화용 고밀도 스팀 플라즈마 제트 온도장 및 방출 스펙트럼 측정)

  • Lee, Sanghyup;Lim, Jihwan;Lee, Dohyung;Yoon, Woongsup
    • Journal of the Korean Society of Propulsion Engineers
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    • v.18 no.1
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    • pp.26-32
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    • 2014
  • In this study, DC (Direct current) type steam plasma igniter is developed for effective ignition of high-energy density metal aluminum and gas temperature is measured by emission spectrum of OH radical. Because of the ultra-high gas temperature, the DC plasma jet is measured by Boltzmann plot method which is the non-contact optical technique and spectrum comparison-analysis. And both methods were applied to experiment after accurate verification. As a result, we could identify that plasma jet temperature is 2900 K ~ 5800 K in the 30 mm range from the nozzle tip.

Measurement of the Slurry Flow-Field during Chemical Mechanical Polishing (Particle Image Velocimetry 기법을 이용하여, Chemical Mechanical Polishing 공정시 Slurry 유동장 측정)

  • Shin, Sang-Hee;Kim, Mun-Ki;Koh, Young-Ho;Kim, Ho-Young;Lee, Jae-Dong;Hong, Chang-Ki;Yoon, Young-Bin
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.11a
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    • pp.125-128
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    • 2004
  • Chemical Mechanical Polishing(CMP) in semiconductor production is characterized its output property by Removal Rate(RR) and Non-Uniformity(NU). Some Previous works shows that RR is determined by production of pressure and velocity and NC is also largely affected by velocity of flow-field during CMP. This study is about the direct measurement of velocity of slurry during CMP and reconstruction whole flow-field by Particle Image Velocimetry(PIV) Techniques. Typical PIV system is tuned adequately for inspecting CMP and Slurry Flow-field is measured by changing both Pad RPM and Carrier RPM. The results show that velocity is majorly determined not by Carrier RPM, but by Pad RPM.

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Prediction of the Radiated Noise from the Vehicle Intake System (자동차 흡기계의 방사소음 예측에 대한 연구)

  • Kim, Hoi-Jeon;Ih, Jeong-Guon;Lee, Seong-Hyun;Shinoda, K.;Kitahara, S.
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.11b
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    • pp.105-108
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    • 2005
  • The radiated noise from the automotive intake system should be predicted at the design stage. To this end, the precise measurement of in-duct acoustic source parameters of the intake system, i.e., the source strength and source impedance, is essential. Most of previous works on the measurement of acoustic source parameters were performed under a fixed engine speed condition. However, the requirement of vehicle manufacturer is the noise radiation pattern as a function of engine speed. In this study, the direct method was employed to measure the source parameters of engine intake system under a fixed engine speed and engine run-up condition. It was noted that the frequency spectra of source impedance hardly changes with varying the engine speed. Thus, it is reasonable to calculate the source strength under the engine run-up condition by assuming that source impedance is invariant with engine speed. Measured and conventional source models, i.e., constant pressure source, constant velocity source, and non-reflective source, were utilized to predict insertion loss and radiated sound pressure level. A reasonable prediction accuracy of radiated sound pressure level spectra from the intake system was given in the test vehicle when using the measured source characteristics which were acquired under the operating condition.

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Real Time ECG Monitoring Through a Wearable Smart T-shirt

  • Mathias, Dakurah Naangmenkpeong;Kim, Sung-Il;Park, Jae-Soon;Joung, Yeun-Ho
    • Transactions on Electrical and Electronic Materials
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    • v.16 no.1
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    • pp.16-19
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    • 2015
  • A wearable sensing ECG T-shirt for ubiquitous vital signs sensing is proposed. The sensor system consists of a signal processing board and capacitive sensing electrodes which together enable measurement of an electrocardiogram (ECG) on the human chest with minimal discomfort. The capacitive sensing method was employed to prevent direct ECG measurement on the skin and also to provide maximum convenience to the user. Also, low power integrated circuits (ICs) and passive electrodes were employed in this research to reduce the power consumption of the entire system. Small flexible electrodes were placed into cotton pockets and affixed to the interior of a worn tight NIKE Pro combat T-shirt. Appropriate signal conditioning and processing were implemented to remove motion artifacts. The entire system was portable and consumed low power compared to conventional ECG devices. The ECG signal obtained from a 24 yr. old male was comparable to that of an ECG simulator.

Characteristic of the Radiation Heat Flux Distribution for the KIER Solar Furnace (KIER 태양로의 열유속 분포 특성)

  • Chai, Kwan-Kyo;Lee, Hyun-Jin;Kim, Jong-Kyu;Yoon, Hwan-Ki;Lee, Sang-Nam;Kang, Yong-Heack;Seo, Tae-Beom
    • 한국태양에너지학회:학술대회논문집
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    • 2011.11a
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    • pp.74-79
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    • 2011
  • Concentration characteristics of the KIER solar furnace are analyzed with a heat flux measurement technique. Total heat capacity of 40kW was confirmed within 1.04% average error, and the normalized maximum heat flux of 3,452 $kW/m^2$ was proved. Non-Gaussian flux distribution in the vertical direction implies that reflectors should not be random rather inclined downwards. Moreover, we characterized flux distribution variations with furnace blind opening ratio, distance from the focal plane, and misalignment of the measurement system. Based on the results, the heat flux distribution can be simply estimated once reflectivity and direct normal insolation values are known. This study will be helpful to the design and the performance evaluation of receivers or chemical reactors.

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Adaptive Wireless Localization Filter Containing NLOS Error Mitigation Function

  • Cho, Seong Yun
    • Journal of Positioning, Navigation, and Timing
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    • v.5 no.1
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    • pp.1-9
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    • 2016
  • Range-based wireless localization system must measure accurate range between a mobile node (MN) and reference nodes. However, non-line-of-sight (NLOS) error caused by the spatial structures disturbs the localization system obtaining the accurate range measurements. Localization methods using the range measurements including NLOS error yield large localization error. But filter-based localization methods can provide comparatively accurate location solution. Motivated by the accuracy of the filter-based localization method, a filter residual-based NLOS error estimation method is presented in this paper. Range measurement-based residual contains NLOS error. By considering this factor with NLOS error properties, NLOS error is mitigated. Also a process noise covariance matrix tuning method is presented to reduce the time-delay estimation error caused by the single dynamic model-based filter when the speed or moving direction of a MN changes, that is the used dynamic model is not fit the current dynamic of a MN. The presented methods are evaluated by simulation allowing direct comparison between different localization methods. The simulation results show that the presented filter is more accurate than the iterative least squares- and extended Kalman filter-based localization methods.

High Quality Non-Transfer Single-Layer Graphene Process Grown Directly on Ti(10 nm)-Buffered Layer for Photo Lithography Process (포토 리소그래피 공정을 위한 Ti(10 nm)-Buffered층 위에 직접 성장된 고품질 무전사 단층 그래핀 공정)

  • Oh, Keo-Ryong;Han, Yire;Eom, Ji-Ho;Yoon, Soon-Gil
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.34 no.1
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    • pp.21-26
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    • 2021
  • Single-layer graphene is grown directly on Ti-buffered SiO2 at 100℃. As a result of the AFM measurement of the Ti buffer layer, the roughness of approximately 0.2 nm has been improved. Moreover, the Raman measurement of graphene grown on it shows that the D/G intensity ratio is extremely small, approximately 0.01, and there are no defects. In addition, the 2D/G intensity ratio had a value of approximately 2.1 for single-layer graphene. The sheet resistance is also 89 Ω/□, demonstrating excellent characteristics. The problem was solved by using graphene and a lift-off patterning method. Low-temperature direct-grown graphene does not deteriorate after the patterning process and can be used for device and micro-patterning research.

Effect of fringe divergence in fluid acceleration measurement using LDA (레이저 도플러 원리를 이용한 유체 가속도 측정)

  • Chun, Se-Jong;Nobach, Holger;Tropea, Cam;Sung, Hyung-Jin
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.1546-1551
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    • 2004
  • The laser Doppler technique is well-established as a velocity measurement technique of high precision for flow velocity. Recently, the laser Doppler technique has also been used to measure acceleration of fluid particles. Acceleration is interesting from a fluid mechanics point of view, since the Navier Stokes equations, specifically the left-hand-side, are formulated in terms of fluid acceleration. Further, there are several avenues to estimating the dissipation rate using the acceleration. However such measurements place additional demands on the design of the optical system; in particular fringe non-uniformity must be held below about 0.0001 to avoid systematic errors. Relations expressing fringe divergence as a function of the optical parameters of the system have been given in the literature; however, direct use of these formulae to minimize fringe divergence lead either to very large measurement volumes or to extremely high intersection angles. This dilemma can be resolved by using an off-axis receiving arrangement, in which the measurement volume is truncated by a pinhole in front of the detection plane. In the present study an optical design study is performed for optimizing laser Doppler systems for fluid acceleration measurements. This is followed by laboratory validation using a round free jet and a stagnation flow, two flows in which either fluid acceleration has been previously measured or in which the acceleration is known analytically. A 90 degree off-axis receiving angle is used with a pinhole or a slit.

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