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High-response and Low-power-consumption CO Micro Gas Sensor Based on Nano-powders and a Micro-heater
문승언,이재운,최낙진,이형근,양우석,김종대,박용주 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.60 No.2
In this research, a CO micro gas sensor was fabricated based on a micro-heater by using a tin oxide nano-powder for effective gas detection and a monitoring system with low power consumption and high sensitivity. Tin-oxide-based nano-powders were fabricated using a conventional method and their structural properties were examined by using the scanning electron microscope, X-ray diffractor,etc. Membrane type micro-heater based on Si substrate was fabricated by using complementary metal-oxide semiconductor (CMOS) compatible micro electro mechanical systems (MEMS) process by using bulk micromachining. The gas sensing properties for slurry-dropped tin oxide thick film device were measured for CO gas. The micro gas sensors showed high sensitivity and low power consumption, about 15 mW power consumption, 2 ppm CO could be detected.
문승언,이성규,Sang-kyun Lee,이영기,Yil Suk Yang,박강호,김종대 한국전자통신연구원 2009 ETRI Journal Vol.31 No.6
In this paper, we present the results of a preliminary study on the piezoelectric energy harvesting performance of a Zr-doped PbMg⅓Nb⅔O₃-PbTiO₃(PMN-PZT) single crystal beam. A novel piezoelectric beam cantilever structure is used to demonstrate the feasibility of generating AC voltage during a state of vibration. The energy-harvesting capability of a PMN-PZT beam is calculated and tested. The frequency response of the cantilever device shows that the first mode resonance frequency of the excitation model exists in the neighborhood of several hundreds of hertz, which is similar to the calculated value. These tests show that several significantly open AC voltages and sub-mW power are achieved. To test the possibility of a small scale power source for a ubiquitous sensor network service, energy conversion and the testing of storage experiment are also carried out.
문승언,임종필,김정훈,이재우,이미영,이주현,강승열,황치선,윤성민,김대환,민경식,박배호,Moon, S.E.,Im, J.P.,Kim, J.H.,Lee, J.,Lee, M.Y.,Lee, J.H.,Kang, S.Y.,Hwan, C.S.,Yoo, S.M.,Kim, D.H.,Min, K.S.,Park, B.H. 한국전자통신연구원 2018 전자통신동향분석 Vol.33 No.6
A neuromorphic hardware that mimics biological perceptions and has a path toward human-level artificial intelligence (AI) was developed. In contrast with software-based AI using a conventional Von Neumann computer architecture, neuromorphic hardware-based AI has a power-efficient operation with simultaneous memorization and calculation, which is the operation method of the human brain. For an ideal neuromorphic device similar to the human brain, many technical huddles should be overcome; for example, new materials and structures for the synapses and neurons, an ultra-high density integration process, and neuromorphic modeling should be developed, and a better biological understanding of learning, memory, and cognition of the brain should be achieved. In this paper, studies attempting to overcome the limitations of next-generation neuromorphic hardware technologies are reviewed.
Semiconductor-Type MEMS Gas Sensor for Real-Time Environmental Monitoring Applications
문승언,최낙진,이형근,이재우,양우석 한국전자통신연구원 2013 ETRI Journal Vol.35 No.4
Low power consuming and highly responsive semiconductor-type microelectromechanical systems (MEMS) gas sensors are fabricated for real-time environmental monitoring applications. This subsystem is developed using a gas sensor module, a Bluetooth module, and a personal digital assistant (PDA) phone. The gas sensor module consists of a NO2 or CO gas sensor and signal processing chips. The MEMS gas sensor is composed of a microheater, a sensing electrode, and sensing material. Metal oxide nanopowder is drop-coated onto a substrate using a microheater and integrated into the gas sensor module. The change in resistance of the metal oxide nanopowder from exposure to oxidizing or deoxidizing gases is utilized as the principle mechanism of this gas sensor operation. The variation detected in the gas sensor module is transferred to the PDA phone by way of the Bluetooth module.
Analysis of Vibration-energy-harvesting Devices based on a Piezoelectric Single Crystal Beam
문승언,이상균,이형근,이재우,양일석,김종대 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.58 No.31
In this paper, we present the results and analyses of vibration-energy-harvesting performances based on single crystal beam. A novel piezoelectric beam cantilever structure is used to measure the generated AC voltage during the vibration. The energy-harvesting capability of piezoelectric single crystal was measured, and the prototype based on a unimorph cantilever structure with a proof mass which were designend to operate at a vibration frequency of about 60 Hz. These tests show that several AC voltages and sub-mW power were achieved. Using the measured mechanical damping ratio and electro-mechanical coupling coefficient of the device, we calculated the output power and compared it with the above measured results.
문승언,Sank Kyun Lee,이영기,김광만,양이석,양우석,김종대 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.60 No.2
In this paper, we present the calculations and the results for vibration-energy-scavenging performances based on a piezoelectric single-crystal beam. Using the measured mechanical damping ratio and electro-mechanical coupling coefficient of a novel cantilever structure device, we calculated the output performances and compared them with the measured results. A device based on a bimorph cantilever structure with a proof mass was designed to have a natural resonance frequency of about 60 Hz, and the energy-scavenging capability of piezoelectric single crystal was measured. The results showed that several tens of AC volts and a few milliwatts power were achieved under a 0.1 grms vibration condition. Also using this device and a commercial power management circuit,we performed Li-ion battery charging experiment. In this paper, we present the calculations and the results for vibration-energy-scavenging performances based on a piezoelectric single-crystal beam. Using the measured mechanical damping ratio and electro-mechanical coupling coefficient of a novel cantilever structure device, we calculated the output performances and compared them with the measured results. A device based on a bimorph cantilever structure with a proof mass was designed to have a natural resonance frequency of about 60 Hz, and the energy-scavenging capability of piezoelectric single crystal was measured. The results showed that several tens of AC volts and a few milliwatts power were achieved under a 0.1 grms vibration condition. Also using this device and a commercial power management circuit,we performed Li-ion battery charging experiment.
문승언,양우석,김종대 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.61 No.6
In this paper, we present the simulation and the experimental results for vibration-energyscavenging performances in a cantilever-type piezoelectric energy scavenger with bandwidth broadening properties by using a variable width structure. Using the measured mechanical damping ratio and electro-mechanical coupling coefficient of the fabricated cantilever-type device, we simulated the output performances and designed a cantilever-type piezoelectric energy scavenger with bandwidth broadening characteristics. A device based on a parallel-bimorph cantilever structure with a proof mass, which was designed to have a natural resonance frequency of about 60 Hz, and the energy-scavenging capability of a piezoelectric single crystal was measured and compared them with the simulated results. The results showed that several tens of ac volts and a few milliwatts of power were achieved under a 0.1 <i>g<sub>rms</sub></i> vibration condition with a 3 Hz bandwidth.
문승언,김정훈,J. P. Im,J. Lee,S. Y. Im,S. H. Hong,S. Y. Kang,S. M. Yoon 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.73 No.11
To study the applications for ferroelectric non-volatile memory and ferroelectric memristor, etc., deposition pressure dependent electric the properties of (Hf; Zr)O2 thin films by RF sputtering deposition method were investigated. The bottom electrode was TiN thin film to produce stress effect on the formation of orthorhombic phase and top electrode was Pt thin film by DC sputtering deposition. Deposition pressure was varied along with the same other deposition conditions, for example, sputtering power, target to substrate distance, post-annealing temperature, annealing gas, annealing time, etc. The structural and electric properties of the above thin films were investigated. As a result, it is confirmed that the electric properties of the (Hf; Zr)O2 thin films depend on the deposition pressure which affects structural properties of the thin films, such as, structural phase, ratio of the constituents, etc.
문승언,J.-W. Lee,박소정,J. Park,K.-H. Park,J. Kim 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.56 No.1
Small-scale, low-power-consumption, and high-sensitivity NO2 gas sensors based on ZnO nanorods are reported in this work. To activate the chemical absorption and desorption for NO2gas, we embedded co-planar micro-heater in a micro gas sensor, that was made by using a Complementary Metal–oxide–semiconductor compatible Microelectromechanical Systems(CMOS-MEMS)process. To acquire simple fabrication and low fabrication cost, we located the micro-heater and the sensing electrode in the same plane. High-quality single-crystalline ZnO nanorods were selectively grown by using photolithography and a hydrothermal method. Their structural properties were confirmed by using X-ray diffractometry (XRD), energy dispersive X-ray spectroscopy microanalysis (EDAX), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). The temperature-dependent current-voltage characteristics were measured to optimize the operating temperature of the fabricated devices as a chemical gas sensor. To test the possibility for use as chemical sensor, we measured the NO2 gas response.
문성오 ( Moon Seong-oh ),모승언 ( Mo Seung-un ),윤예빈 ( Youn Ye-bin ) 한국건축시공학회 2020 한국건축시공학회 학술발표대회 논문집 Vol.20 No.2
The Temporary construction refers to the construction or dismantling of temporary structures installed for the construction of the main structure at the construction site, and the members constituting this temporary facility are called temporary equipment. Temporary equipment used in construction sites is mostly used products that are reused rather than new products, and it is necessary to consider performance degradation due to repeated use. This study is a preliminary study to develop the performance evaluation criteria applied to temporary equipment that is distributed and reused for secondhand. This study is to analyze the performance status of temporary equipment of used goods owned by rental companies by condition grade through performance tests.