• Title/Summary/Keyword: Bio-sensors

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Electrical conductivity and stealth characteristics of copper-sputtered clothing materials - Focusing on changes in the pore size of clothing materials - (구리 스퍼터링 의류소재의 전기전도성과 스텔스 특성 - 의류소재 기공 크기 변화를 중심으로 -)

  • Hye Ree Han
    • The Research Journal of the Costume Culture
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    • v.31 no.1
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    • pp.107-123
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    • 2023
  • This research studied the electrical characteristics, IR transmission characteristics, stealth functions, and thermal characteristics of infrared thermal-imaging cameras of copper-sputtered samples. Nylon samples were prepared for each density as a base material for copper-sputtering treatment. Copper-sputtered NFi, NM1, NM2, NM3, NM4, and NM5, showed electrical resistance of 0.8, 445.7, 80.7, 29.7, 0.3, and 2.2 Ω, respectively, all of which are very low values; for the mesh sample, the lower the density, the lower the electrical resistance. Measuring the IR transmittance showed that the infrared transmittance of the copper-sputtered samples was significantly reduced compared to the untreated sample. Compared to the untreated samples, the transmittance went from 92.0-64.1%. When copper sputtered surface was directed to the IR irradiator, the IR transmittance went from 73.5 to 43.8%. As the density of the sample increased, the transmittance tended to decreased. After the infrared thermal imaging, the absolute values of △R, △G, and △B of the copper phase increased from 2 to 167, 98 to 192, and 7 to 118, respectively, and the closer the density of the sample (NM5→NFi), the larger the absolute value. This proves that the dense copper phase-up sample has a stealth effect on the infrared thermal imaging camera. It is believed that the copper-sputtered nylon samples produced in this study have applications in multifunctional uniforms, bio-signal detection sensors, stage costumes, etc.

Light Emitting Diode with Multi-step Quantum Well Structure for Sensing Applications (계단형 양자우물 구조가 적용된 센서 광원 용 발광다이오드 소자)

  • Seongmin Park;Seungjoo Lee;Jajeong Woo;Yukyung Kim;Soohwan Jang
    • Journal of Sensor Science and Technology
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    • v.32 no.6
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    • pp.441-446
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    • 2023
  • Electrical and optical characteristics of the GaN-based light-emitting diode (LED) with the improved multi-quantum well (MQW) structure have been studied for light source in bio-sensing systems. Novel GaN/In0.1GaN/In0.2GaN/In0.1GaN/GaN and Al0.1GaN/GaN/In0.2GaN/GaN/Al0.1GaN (MQW) structures were suggested, and their radiative recombination rate, light output power, electroluminescence, and external quantum efficiency were compared with those of the conventional GaN/In0.2GaN/GaN MQW structure using device simulation. The LED with the GaN/In0.1GaN/In0.2GaN/In0.1GaN/GaN MQW structure showed an excellent recombination rate of 5.57 × 1028 cm-3·s-1 that was more than one order improvement over that of the conventional LED. In addition, the efficiency droop was relieved by the suggested stepped MQW structure.

Analysis of Air Temperature and Humidity Distributions and Energy Consumptions according to Use of Air Circulation Fans in a Single-span Greenhouse (단동온실 내 공기순환팬 사용에 따른 온습도 및 에너지소비량 비교 분석)

  • Lee, Tae Seok;Kang, Geum Choon;Kim, Hyung Kweon;Moon, Jong Pil;Oh, Sung Sik;Kwon, Jin Kyung
    • Journal of Bio-Environment Control
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    • v.26 no.4
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    • pp.276-282
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    • 2017
  • The aim of this study was to compare and analyze air temperature and humidity distribution and energy consumptions according to using air circulation fans in single-span greenhouses. The greenhouses located in Cheongnam-myeon, Cheongyang-gun, Chungcheongnam-do, Korea. There were cherry tomatoes in the greenhouses and the size of greenhouses was as follows;ridge height : 3.2 m, wide : 6 m, length : 95 m. The heating system was composed of a hot-water boiler and 6 FCUs(Fan Coil Unit)-4 FCUs were on bottom with duct and 2 FCUs were installed at 2.0 m. A total of 18 air circulation fans(impeller's diameter : 230 mm) were bilaterally arranged in 2 rows in the experimental greenhouse. The sensors for measuring air temperature and humidity were located at a quarter and three quarters of a length. The height of sensors were 0.8 m, 1.8 m. To calculate energy consumption in greenhouses, water temperature at inlet and outlet in a water pump, volume of water were measured. Form February 3rd to March 23th, temperature, humidity and energy consumptions were measured during heating time(6pm~7am). In a greenhouse without fans, the average differences of temperature and humidity were $0.75^{\circ}C$, 2.31%, respectively. The operation of fans showed their differences to $0.42^{\circ}C$, 1.8%. The standard deviation of temperature and humidity between measuring points in the greenhouse with fans was lower than the greenhouse without fans. Total energy consumptions in a greenhouse without fans were 4,673 kWh. In the greenhouse with fans, the total energy consumptions were 4,009 kWh. The energy consumptions in a greenhouse with fans 14.2% were less than the greenhouse without fans. Therefore, air circulation makes temperature and humidity uniform and saves energy consumptions for heating.

Analysis of Spatial and Vertical Variability of Environmental Parameters in a Greenhouse and Comparison of Carbon Dioxide Concentration in Two Different Types of Greenhouses (온실 환경요인의 공간적 및 수직적 특성 분석과 온실 종류에 따른 이산화탄소 농도 비교)

  • Jeong, Young Ae;Jang, Dong Cheol;Kwon, Jin Kyung;Kim, Dae Hyun;Choi, Eun Young
    • Journal of Bio-Environment Control
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    • v.31 no.3
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    • pp.221-229
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    • 2022
  • This study was aimed to investigate spatial and vertical characteristics of greenhouse environments according to the location of the environmental sensors, and to investigate the correlations between temperature, light intensity, and carbon dioxide (CO2) concentration according to the type of greenhouse. Temperature, relative humidity (RH), CO2, and light sensors were installed in the four-different vertical positions of the whole canopy as well as ground and roof space at the five spatial locations of the Venlo greenhouse. Also, correlations between temperature, light intensity, and CO2 concentration in Venlo and semi-closed greenhouses were analyzed using the Curve Expert Professional program. The deviations among the spatial locations were larger in the CO2 concentration than other environmental factors in the Venlo greenhouse. The average CO2 concentration ranged from 465 to 761 µmol·mol-1 with the highest value (646 µmol·mol-1) at the Middle End (4ME) close to the main pipe (50Ø) of the liquefied CO2 gas supply and lowest (436 µmol·mol-1) at the Left Middle (5LM). The deviation among the vertical positions was greater in temperature and relative humidity than other environments. The time zone with the largest deviation in average temperature was 2 p.m. with the highest temperature (26.51℃) at the Upper Air (UA) and the lowest temperature (25.62℃) at the Lower Canopy (LC). The time zone with the largest deviation in average RH was 1 p.m. with the highest RH (76.90%) at the LC and the lowest RH (71.74%) at the UA. The highest average CO2 concentration at each hour was Roof Air (RF) and Ground (GD). The coefficient of correlations between temperature, light intensity, and CO2 concentration were 0.07 for semi-closed greenhouse and 0.66 for Venlo greenhouse. All the results indicate that while the CO2 concentration in the greenhouse needs to be analyzed in the spatial locations, temperature and humidity needs to be analyzed in the vertical positions of canopy. The target CO2 fertilization concentration for the semi-closed greenhouse with low ventilation rate should be different from that of general greenhouses.

Monitoring the Reoccurrence of Fire Blight and the Eradication Efficiency of Erwinia amylovora in Burial Sites of Infected Host Plants Using Sentinel Plants (미끼식물을 이용한 화상병 감염 기주 매몰지 내 화상병균 제거 효율 검증 및 병 재발 모니터링)

  • In Woong, Park;Yu-Rim, Song;Nguyen Trung, Vu;Eom-Ji, Oh;In Sun, Hwang;Hyeonheui, Ham;Seong Hwan, Kim;Duck Hwan, Park;Chang-Sik, Oh
    • Research in Plant Disease
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    • v.28 no.4
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    • pp.221-230
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    • 2022
  • The fire blight caused by Erwinia amylovora (Ea) was first reported in 2015 in Korea, and the disease has rapidly spread to 22 regions until 2021. In Korea, all host plants in the apple and pear orchards where fire blight occurred should be eliminated and buried by the Plant Protection Act. To prevent the spread of the disease, all burial sites were prohibited from planting the new host plants for the next three years. To confirm the eradication efficiency of Ea and the reoccurrence of fire blight, the surveillance facilities were established on three burial sites from 2019 to 2020 in Anseong-si, Gyeonggi-do, and Chungju-si, Chungcheongbuk-do. As host plants, five apple trees of fire blight-susceptible cultivar 'Fuji', were planted in each facility. All facilities were enclosed with fences and nets and equipped with two CCTVs, motion sensors, and several other sensors for recording weather conditions to monitor the environment of the sentinel plants in real-time. The sentinel plants were checked for the reoccurrence of fire blight routinely. Suspicious plant parts were collected and analyzed for Ea detection by loop-mediated isothermal amplification polymerase chain reaction and conventional polymerase chain reaction. Until November 2022, Ea has not been detected in all sentinel plants. These results might support that the burial control of infected plants in soil works efficiently to remove Ea and support the possibility to shorten the prohibition period of host plant establishment in the burial sites.

The Surface Treatment Effect for Nanoimprint Lithography using Vapor Deposition of Silane Coupling Agent (나노임프린트 공정에서 실란커플링제 기상증착을 이용한 표면처리 효과)

  • Lee, Dong-Il;kim, Ki-Don;Jeong, Jun-Ho;Lee, Eung-Sug;Choi, Dae-Geun
    • Korean Chemical Engineering Research
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    • v.45 no.2
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    • pp.149-154
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    • 2007
  • Nanoimprint lithography (NIL) is useful technique because of its low cost and high throughput capability for the fabrication of sub-micrometer patterns which has potential applications in micro-optics, magnetic memory devices, bio sensors, and photonic crystals. Usually, a chemical surface treatment of the stamp is needed to ensure a clean release after imprinting and to protect the expensive original master against contamination. Meanwhile, adhesion promoter between resin and substrate is also important in the nanoscale pattern. In this work, we have investigated the effect of surface treatment using silane coupling agent as release layer and adhesion promoter for UV-Nanoimprint lithography. Uniform SAM (self-assembled monolayer) could be fabricated by vapor deposition method. Vapor phase process eliminates the use of organic solvents and greatly simplifies the handling of the sample. It was also proven that 3-acryloxypropyl methyl dichlorosilane (APMDS) could strongly improve the adhesion force between resin and substrate compared with common planarization layer such as DUV-30J or oxygen plasma treatment.

Morphology Control of Nanostructured Graphene on Dielectric Nanowires

  • Kim, Byeong-Seong;Lee, Jong-Un;Son, Gi-Seok;Choe, Min-Su;Lee, Dong-Jin;Heo, Geun;Nam, In-Cheol;Hwang, Seong-U;Hwang, Dong-Mok
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.08a
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    • pp.375-375
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    • 2012
  • Graphene is a sp2-hybridized carbon sheet with an atomic-level thickness and a wide range of graphene applications has been intensely investigated due to its unique electrical, optical, and mechanical properties. In particular, hybrid graphene structures combined with various nanomaterials have been studied in energy- and sensor-based applications due to the high conductivity, large surface area and enhanced reactivity of the nanostructures. Conventional metal-catalytic growth method, however, makes useful applications difficult since a transfer process, used to separate graphene from the metal substrate, should be required. Recently several papers have been published on direct graphene growth on the two dimensional planar substrates, but it is necessary to explore a direct growth of hierarchical nanostructures for the future graphene applications. In this study, uniform graphene layers were successfully synthesized on highly dense dielectric nanowires (NWs) without any external catalysts. We also demonstrated that the graphene morphology on NWs can be controlled by the growth parameters, such as temperature or partial pressure in chemical vapor deposition (CVD) system. This direct growth method can be readily applied to the fabrication of nanoscale graphene electrode with designed structures because a wide range of nanostructured template is available. In addition, we believe that the direct growth growth approach and morphological control of graphene are promising for the advanced graphene applications such as super capacitors or bio-sensors.

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Hybrid Fabrication of Screen-printed Pb(Zr,Ti)O3 Thick Films Using a Sol-infiltration and Photosensitive Direct-patterning Technique (졸-침투와 감광성 직접-패턴 기술을 이용하여 스크린인쇄된 Pb(Zr,Ti)O3 후막의 하이브리드 제작)

  • Lee, J.-H.;Kim, T.S.;Park, H.-H.
    • Journal of the Microelectronics and Packaging Society
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    • v.22 no.4
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    • pp.83-89
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    • 2015
  • In this paper, we propose a fabrication technique for enhanced electrical properties of piezoelectric thick films with excellent patterning property using sol-infiltration and a direct-patterning process. To achieve the needs of high-density and direct-patterning at a low sintering temperature (< $850^{\circ}C$), a photosensitive lead zirconate titanate (PZT) solution was infiltrated into a screen-printed thick film. The direct-patterned PZT films were clearly formed on a locally screen-printed thick film, using a photomask and UV light. Because UV light is scattered in the screen-printed thick film of a porous powder-based structure, there are needs to optimize the photosensitive PZT sol infiltration process for obtaining the enhanced properties of PZT thick film. By optimizing the concentration of the photosensitive PZT sol, UV irradiation time, and solvent developing time, the hybrid films prepared with 0.35 M of PZT sol, 4 min of UV irradiation and 15 sec solvent developing time, showed a very dense with a large grain size at a low sintering temperature of $800^{\circ}C$. It also illustrated enhanced electrical properties (remnant polarization, $P_r$, and coercive field, $E_c$). The $P_r$ value was over four times higher than those of the screen-printed films. These films integrated on silicon wafer substrate could give a potential of applications in micro-sensors and -actuators.

Analysis of Power Requirement of Agricultural Tractor during Baler Operation (베일러 작업 시 트랙터 소요동력 분석)

  • Kim, Yong-Joo;Lee, Dae-Hyun;Chung, Sun-Ok;Park, Seung-Jae;Choi, Chang-Hyun
    • Journal of Biosystems Engineering
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    • v.36 no.4
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    • pp.243-251
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    • 2011
  • Purpose of this study was to analyze power requirement of an agricultural tractor for baler operation. First, a power measurement system was developed and installed in a 75 kW agricultural tractor. Strain-gages with a telemetry system were used to measure torques of transmission and PTO input shafts. An engine tachometer was used to measure rotational speed of transmission and PTO input shafts. The measurement system also included pressure sensors to measure pressure of hydraulic pumps, an I/O interface to acquire the sensor signals, and an embedded system to determine power requirements. Second, field experiments were conducted at two PTO speed levels, and proportion of utilization ratio of rated engine power and power consumption of major parts (transmission input shaft, PTO input shaft, main hydraulic pump, and auxiliary hydraulic pump) were analyzed. Results of usage proportion of engine power for PTO speed level 1 and 2 were 4.1 and 2.2%, 31.5 and 16.3%, 49.6 and 59.7%, 14.4 and 20.8%, and 0.4 and 1.0%, respectively, for ratio of measured engine power to rated engine power of less than 25%, 25 ~ 50%, 50 ~ 75%, 75 ~ 100%, and greater than 100%. The results showed that the usage proportion increased in the range with the ratio of power requirement to rated engine power of over than 50% when the PTO gear was shifted from P1 to P2. Averaged engine power requirement for baling operation, tying and discharging operation, and total operation were 43.3, 37.3, and 42.0 kW and 49.0, 37.0, and 47.4 kW, respectively, for PTO speed level 1 and 2. Paired t-test showed significant difference in power consumption of engine, transmission input shaft, and PTO input shaft for different PTO speed levels. Therefore, the power consumption of engine for baler operation increased when the PTO gear was shifted from P1 to P2. It was indicated that the power requirement of tractor was affected by the PTO rotational speed for baler operation.

Development of a Classification Model for Driver's Drowsiness and Waking Status Using Heart Rate Variability and Respiratory Features

  • Kim, Sungho;Choi, Booyong;Cho, Taehwan;Lee, Yongkyun;Koo, Hyojin;Kim, Dongsoo
    • Journal of the Ergonomics Society of Korea
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    • v.35 no.5
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    • pp.371-381
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    • 2016
  • Objective:This study aims to evaluate the features of heart rate variability (HRV) and respiratory signals as indices for a driver's drowsiness and waking status in order to develop the classification model for a driver's drowsiness and waking status using those features. Background: Driver's drowsiness is one of the major causal factors for traffic accidents. This study hypothesized that the application of combined bio-signals to monitor the alertness level of drivers would improve the effectiveness of the classification techniques of driver's drowsiness. Method: The features of three heart rate variability (HRV) measurements including low frequency (LF), high frequency (HF), and LF/HF ratio and two respiratory measurements including peak and rate were acquired by the monotonous car driving simulation experiments using the photoplethysmogram (PPG) and respiration sensors. The experiments were repeated a total of 50 times on five healthy male participants in their 20s to 50s. The classification model was developed by selecting the optimal measurements, applying a binary logistic regression method and performing 3-fold cross validation. Results: The power of LF, HF, and LF/HF ratio, and the respiration peak of drowsiness status were reduced by 38%, 22%, 31%, and 7%, compared to those of waking status, while respiration rate was increased by 3%. The classification sensitivity of the model using both HRV and respiratory features (91.4%) was improved, compared to that of the model using only HRV feature (89.8%) and that using only respiratory feature (83.6%). Conclusion: This study suggests that the classification of driver's drowsiness and waking status may be improved by utilizing a combination of HRV and respiratory features. Application: The results of this study can be applied to the development of driver's drowsiness prevention systems.