• Journal of Sensor Science and Technology
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• v.3 no.2
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• pp.74-80
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• 1994

Silicon direct bonding technology is very attractive for both silicon-on-insulator devices and sensor fabrication because of its thermal stress free structure and stability. The process of SDB includes hydration of silicon wafer and heat treatment in a wet oxidation furnace. After hydration process, hydroxyl groups of silicon wafer were analyzed by using Fourier transformation-infrared spectroscopy. In case of hydrophilic treatment using a ($H_{2}O_{2}\;:\;H_{2}SO_{4}$) solution, hydroxyl groups are observed in a broad band around the 3474 $cm^{-1}$ region. However, hydroxyl groups do not appear in case of diluted HF solution. The bonded wafer was etched by using tetramethylammonium hydroxide etchant. The surface of the self etch-stopped silicon dioxide is completely flat, so that it can be used as sensor applications such as pressure, flow and acceleration, etc..

• Journal of Sensor Science and Technology
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• v.13 no.2
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• pp.128-132
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• 2004

Short wave infrared (SWIR) photovoltaic devices have been fabricated from metal organic vapour phase epitaxy (MOVPE) grown n- on p- HgCdTe films on GaAs substrates. The MOVPE grown films were processed into mesa type discrete devices with wet chemical etching employed for meas delineation and ZnS surface passivatlon. ZnS was thermally evaporated from effusion cell in an ultra high vacuum (UHV) chamber. The main features of the ZnS deposited from effusion cell in UHV chamber are low fixed surface charge density, and small hysteresis. It was found that a negative flat band voltage with -0.6 V has been obtained for Metal Insulator Semiconductor (MIS) capacitor which was evaporated at $910^{\circ}C$ for 90 min. Current-Voltage (I-V) and temperature dependence of the I-V characteristics were measured in the temperature range 80 - 300 K. The Zero bias dynamic resistance-area product ($R_{0}A$) was about $7500{\Omega}-cm^{2}$ at room temperature. The physical mechanisms that dominate dark current properties in the HgCdTe photodiodes are examined by the dependence of the $R_{0}A$ product upon reciprocal temperature. From theoretical considerations and known current expressions for thermal and tunnelling process, the device is shown to be diffusion limited up to 180 K and g-r limited at temperature below this.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.2
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• pp.92-103
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• 2003

Research and technological advances in the field of remote sensing have greatly enhanced the ability to detect and quantify physical and biological stresses that affect the productivity of agricultural crops. Reflectance in specific visible and near-infrared regions of the electromagnetic spectrum have proved useful in detection of nutrient deficiencies. Especially crop canopy sensors as a ground remote sensing measure the amount of light reflected from nearby surfaces such as leaf tissue or soil and is in contrast to aircraft or satellite platforms that generate photographs or various types of digital images. Multi-spectral vegetation indices derived from crop canopy reflectance in relatively wide wave band can be used to monitor the growth response of plants in relation to environmental factors. The normalized difference vegetation index (NDVI), where NDVI = (NIR-Red)/(NIR+Red), was originally proposed as a means of estimating green biomass. The basis of this relationship is the strong absorption (low reflectance) of red light by chlorophyll and low absorption (high reflectance and transmittance) in the near infrared (NIR) by green leaves. Thereafter many researchers have proposed the other indices for assessing crop vegetation due to confounding soil background effects in the measurement. The green normalized difference vegetation index (GNDVI), where the green band is substituted for the red band in the NDVI equation, was proved to be more useful for assessing canopy variation in green crop biomass related to nitrogen fertility in soils. Consequently ground remote sensing as a non destructive real-time assessment of nitrogen status in plant was thought to be useful tool for site specific crop nitrogen management providing both spatial and temporal information.

• Journal of Advanced Navigation Technology
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• v.24 no.1
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• pp.9-15
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• 2020

Recently, active electronically scanned array (AESA) radar, electro-optical and infrared (EO-IR) and infra-red search and track (IRST) sensors are under development in the Korean fighter experimental(KF-X) project, and AESA radar is currently undergoing preliminary research for flight testing. This paper focuses on the flying test bed (FTB) aircraft operation cases of developed countries in accordance with AESA radar development. As a result, we review domestic laws and regulations related to the airworthiness for FTB aircraft to operate in domestic environment and look for ways to operate FTB aircraft. Therefore, we propose how to selecting, airworthiness and operating FTB aircraft suitable for the domestic environment.

• Journal of Sensor Science and Technology
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• v.10 no.6
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• pp.273-278
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• 2001

Absorption spectra of blood components have been measured for the purpose of predicting the total hemoglobin concentration. We obtained absorption spectra of major blood components from the visible to near-infrared of $400{\sim}2500nm$ region. In the near-infrared, water is the main absorbing constituent. The amount of water in the sample cell varies depending on the volume of solute concentration(water displacement). We acquired water-compensated spectra by considering the variation of water volume depending on the variation of analyze concentration. Those spectra show inherent absorption peaks of analyzes and linearity with respect to concentration. We selected wavelengths for non-invasive measurement of hemoglobin concentration considering the scattering effect of tissue and the interference of other blood components.

• Journal of the Semiconductor & Display Technology
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• v.2 no.4
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• pp.37-40
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• 2003

We have studied micro-machining technologies to fabricate parts and sensors used in the semiconductor equipment. The studies were based on the silicon integrated circuit processes, and composed of the anisotropic etching of single crystal silicon to fabricate a membrane structure for hot and cold junctions in the infrared absorber. KOH and TMAH were used as etching solutions for the anisotropic wet etching for membrane structure formation. The etching characteristic was observed for the each solution, and etching rate was measured depending upon the temperature and concentration of the etching solution. The different characteristics were observed according to pattern directions and etchant concentration. The pattern was made to incline $45^{\circ}$ on the primary flat, and optimum etching property was obtained in the case of 30 wt% and $90^{\circ}C$ of KOH etching solution for the formation of the membrane structure.

• International Journal of Internet, Broadcasting and Communication
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• v.7 no.1
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• pp.15-19
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• 2015

The depth information of an image is used in a variety of applications including 2D/3D conversion, multi-view extraction, modeling, depth keying, etc. There are various methods to acquire depth information, such as the method to use a stereo camera, the method to use the depth camera of flight time (TOF) method, the method to use 3D modeling software, the method to use 3D scanner and the method to use a structured light just like Microsoft's Kinect. In particular, the depth camera of TOF method measures the distance using infrared light, whereas TOF sensor depends on the sensitivity of optical light of an image sensor (CCD/CMOS). Thus, it is mandatory for the existing image sensors to get an infrared light image by bundling several pixels; these requirements generate a phenomenon to reduce the resolution of an image. This thesis proposed a measure to acquire a high-resolution image through gradual area movement while acquiring a low-resolution image through pixel bundling method. From this measure, one can obtain an effect of acquiring image information in which illumination intensity (lux) and resolution were improved without increasing the performance of an image sensor since the image resolution is not improved as resolving a low-illumination intensity (lux) in accordance with the gradual pixel bundling algorithm.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.1
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• pp.157-164
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• 2021

Wind and temperature were measured with a three-dimensional ultrasonic anemometer and the carbon dioxide concentration was measured using an infrared sensor in the tidal flat of Suncheon Bay. In general, as the temperature increases, the concentration of carbon dioxide increases, and as the temperature decreases, the carbon dioxide also decreases in the atmosphere. However, since photosynthesis declined immediately after the sunset, the concentration of carbon dioxide increased as the temperature decreased. In addition, near the high tide when the tidal flat is covered with seawater, the atmospheric turbulence was strong despite an increase in temperature, resulting in a decrease in carbon dioxide concentration. It is necessary to quantitatively evaluated the effects of photosynthesis, respiration and atmospheric turbulence on the change of carbon dioxide concentration over tidal flat ecosystems.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.5
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• pp.873-882
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• 2022

In this paper, we studied the voice recognition system kiosk for convenience, thinking that the kiosk widely used in modern society should compensate for the inconvenience of using by the visually impaired. Using ultrasonic sensor and PIR(Passive Infrared), it recognizes the visually impaired within the range of 80cm-40cm, introduces the kiosk through the MP3 module and induces them to come closer. Also, when the visually impaired within 40cm is recognized, the product description and order are guided through the MP3 module. A recording-based data voice recognition system and a kiosk that outputs desired items through servo motors were studied. A kiosk for the convenience of the visually impaired was manufactured through operation and optimization experiments of PIR, ultrasonic, voice recognition, and shock sensor for the manufactured voice recognition kiosk. Finally, it was confirmed that security can be strengthened by using shock sensors and emergency bells to enhance security.

• The Research Journal of the Costume Culture
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• v.30 no.4
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• pp.579-593
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• 2022

This study examines the surface characteristics, electrical conductivity, electromagnetic wave blocking characteristics, infrared (IR) transmittance, stealth function, thermal characteristics, and moisture characteristics of IR thermal imaging cameras. Nylon film (NFi), nylon fabric (NFa), and 5 types of nylon mesh were selected as the base materials for aluminum sputtering, and aluminum sputtering was performed to study IR thermal imaging, color difference, temperature change, and so on, and the relationship with infrared transmittance was assessed. The electrical conductivity was measured and the aluminum-sputtered nylon film demonstrated 25.6kΩ of surface resistance and high electrical conductivity. In addition, the electromagnetic wave shielding characteristics of the sputtering-treated nylon film samples were noticeably increased as a result of aluminum sputtering treatment as measured by the electromagnetic wave blocking characteristics. When NFi and NFa samples with single-sided sputtering were placed on the human body (sputtering layer faced the outside air) and imaged using IR thermographic cameras, the sputtering layer displayed a color similar to the surroundings, showing a stealth effect. Moreover, the tighter the sample density, the better the stealth function. According to the L, a, b measurements, when the sputtering layer of NFi and NFa samples faced the outside air, the value of a was generally high, thereby demonstrating a concealing effect, and the △E value was also high at 124.2 and 93.9, revealing a significant difference between the treated and untreated samples. This research may be applicable to various fields, such as the military wear, conductive sensors, electromagnetic wave shielding film, and others.