• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.3
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• pp.341-346
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• 2008

This paper is to develop a monitoring system with diagnosis for smart cargo sensors that is for management and maintenance of the liquid cargo ships. The main goal of the system is to achieve the total automation system of the cargo sensor. By this study, the active smart sensor for the liquid cargo ships is designed and developed that guarantees high-confidence, stability, and durability. The proposed system consists of a monitoring part of the steam pressure, high-level monitoring, over flowing monitoring, gas monitoring, and tank temperature monitoring. The signals transferred from each unit system are used for sensor diagnosis based on confidence and accuracy. Finally, in this study, the total supervisory monitoring system is developed to maintain and manage the cargo effectively based on fault diagnosis and prognosis of the each sensor system.

• Journal of Sensor Science and Technology
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• v.13 no.3
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• pp.182-187
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• 2004

The fluorinated amorphous carbon thin films (a-C:F) were deposited by PECVD(plasma enhanced chemical vapor deposition). The precursors were $C_{4}F_{8}$ which had a similar ratio of target film's carbon to fluorine ratio, and $Si_{2}H_{6}$/He for capturing excessive fluorine ion. We varied deposition condition of temperature and working pressure to survey the effect of each changes. We measured dielectric constant, composition, and etc. At low temperature the film adhesion to substrate was very poor although the growth rate was very high, the growth rate was very low at high temperature. The EDS(energy dispersive spectroscopy) result showed carbon and fluorine peak for films and Si peak for substrate. There was no oxygen peak.

• Journal of Sensor Science and Technology
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• v.6 no.3
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• pp.188-193
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• 1997

The lanthanum-modified lead titanate (PLT) thin films on (100) cleaved MgO single crystal substrate have been prepared by RF magnetron sputtering method using PbO-rich target with varing La contents. The substrate temperature, working pressure, $Ar/O_{2}$, and RF power density of PLT thin films were $580^{\circ}C$ 10mTorr, 10/1, and $1.7W/cm^{2}$, respectively. In these conditions, the c-axis growth and tetragonality of the PLT thin films decreased for addition of La content and the PLT thin films showed diffuse phase transition from high temperature XRD patterns. The infrared sensor was fabricated. The remanent polarization was above $1.71{\mu}C/cm^{2}$ and the pyroelectric voltage was above 500mV with 10:1 signal to noise ratio.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.4
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• pp.613-618
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• 2012

The Ultrasonic metal welding is used in the solid-phase welding method at room temperature or low temperature state. In welding process, the high frequency vibration energy is delivered to the welding part under the constant pressure for welding. In this study, we aimed to design and manufacture a 40,000 Hz band horn through finite element analysis. By performing modal analysis and harmonic response analysis, the modal analysis result is that the horn frequency was 39,599Hz and the harmonic response result that the horn frequency was 39,533Hz. These results were similar. In order to observe the designed horn's performance, about 4,000 voltage data was obtained from a light sensor and was analyzed by FFT analysis using Origin Tool. The result RMS amplitude was approximately $8.5{\mu}m$ at 40,000Hz, and maximum amplitude was $12.3{\mu}m$. Using this manufactured horn along with an ultrasonic metal welder and tension tester, the weldability of Cu sheets was evaluated. The maximum tensile force was 66.53 N in the welding condition of 2.0 bar pressure, 60% amplitude, and 0.32 s welding time. In excessive welding conditions, it was revealed that weldability is influenced negatively.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.2
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• pp.1-6
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• 2008

In recent years, developments in the semiconductor and electronic industries have brought a rapid increase in the use of large size silicon wafer. For further improvement of the ultra precision surface and flatness of Si wafer necessary to high density ULSI, it is known that polishing is very important. However, most of these investigation was experiment less than 300mm diameter. Polishing is one of the important methods in manufacturing of Si wafers and in thinning of completed device wafers. This study reports the machining variables that has major influence on the characteristic of wafer polishing. It was adapted to polishing pressure, machining speed, and the slurry mix ratio, the optimum condition is selected by ultra precision wafer polishing using load cell and infrared temperature sensor. The optimum machining condition is selected a result data that use a pressure and table speed data. By using optimum condition, it achieves a ultra precision mirror like surface.

• Journal of Sensor Science and Technology
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• v.29 no.5
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• pp.354-359
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• 2020

The high vacuum hermetic sealing technique ensures excellent performance of MEMS resonators. For the high vacuum hermetic sealing, the customization of anodic bonding equipment was conducted for the glass/Si/glass triple-stack anodic bonding process. Figure 1 presents the schematic of the MEMS resonator with triple-stack high-vacuum anodic bonding. The anodic bonding process for vacuum sealing was performed with the chamber pressure lower than 5 × 10^-6 mbar, the piston pressure of 5 kN, and the applied voltage was 1 kV. The process temperature during anodic bonding was 400 ℃. To maintain the vacuum condition of the glass cavity, a getter material, such as a titanium thin film, was deposited. The getter materials was active at the 400 ℃ during the anodic bonding process. To read out the electrical signals from the Si resonator, a vertical feed-through was applied by using through glass via (TGV) which is formed by sandblasting technique of cap glass wafer. The aluminum electrodes was conformally deposited on the via-hole structure of cap glass. The TGV process provides reliable electrical interconnection between Si resonator and aluminum electrodes on the cap glass without leakage or electrical disconnection through the TGV. The fabricated MEMS resonator with proposed vacuum packaging using three-layer anodic bonding process has resonance frequency and quality factor of about 16 kHz and more than 40,000, respectively.

• Journal of IKEEE
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• v.26 no.2
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• pp.219-225
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• 2022

The textile industry in Korea, the dyeing sector is an energy-intensive sector and has low per-unit productivity due to its labor-intensive nature. If the defective rate of dyed fabrics is high, additional costs are incurred due to an increase in production cost due to re-dyeing. Therefore, the goal of the dyeing factory was to minimize the defect rate rather than to save energy. It was difficult to check the dyeing state of the fabric in real time due to the risk of accidents due to burns or pressure when dyeing in a high-temperature and high-pressure environment. In this paper, a complex sensor that can measure the exhaustion rate of dye solution in the dyeing machine using turbidity, pH, and conductivity sensors was proposed, and the experimental method and experimental results were analyzed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.78-79
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• 2008

In this paper, poly 3C-SiC thin films were grown on $SiO_2$/Si by atmospheric pressure chemical vapor deposition (APCVD) using HMDS, $H_2$, and Ar gas at $1100^{\circ}C$ for 30 min, respectively. And then, palladium films were deposited on poly 3C-SiC by RF magnetron sputter. Thickness, uniformity, and quality of these samples were performed by SEM. Crystallinity and preferred orientationsof palladium were analyzed by XRD. And Pd/poly 3C-SiC schottky diodes were fabricated and characterized by current-voltage measurements. Its electric current density Js and barrier height voltage were measured as $2\times10^{-3}$ A/$cm^2$, 0.58 eV, respectively. And these devices operated about $350^{\circ}C$. From results, Pd/poly 3C-SiC devices are promising for high temperature hydrogen sensor and applications.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.28.1-28.1
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• 2009

The superior properties of ZnO such as high exciton binding energy, high thermal and chemical stability, low growth temperature and possibility of wet etching process in ZnO have great interest for applications ranging from optoelectronics to chemical sensor. Particularly, vertically well-aligned ZnO nanorods on large areas with good optical and structural properties are of special interest for the fabrication of electronic and optical nanodevices. Currently, low-dimensional ZnO is synthesized by metal-organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), thermal evaporation, and sol.gel growth. Recently, our group has been reported about achievement the growth of Ga-doped ZnO nanorods using ZnO seed layer on p-type Si substrate by RF magnetron sputtering system at high rf power and high growth temperature. However, the crystallinity of nanorods deteriorates due to lattice mismatch between nanorods and Si substrate. Also, in the growth of oxide using sputtering, the oxygen flow ratio relative to argon gas flow is an important growth parameter and significantly affects the structural properties. In this study, Phosphorus (P) doped ZnO nanorods were grown on c-sapphire substrates without seed layer by radio frequency magnetron sputtering with various argon/oxygen gas ratios. The layer change films into nanorods with decreasing oxygen partial pressure. The diameter and length of vertically well-aligned on the c-sapphire substrate are in the range of 51-103 nm and about 725 nm, respectively. The photoluminescence spectra of the nanorods are dominated by intense near band-edge emission with weak deep-level emission.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1458-1462
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• 2003

High temperature and high pressure heavy water flows through the pipes in atomic power plants. The curved parts of pipes are critical parts in that they change the direction of steam flow, and these parts are especially affected by severe wear. Therefore, most pipes in atomic power plants are tested by non-destructive examination by workers who use ultrasonic sensors to measure the wall thickness of pipes. But not only are these pipes located in a very dangerous environment, but the space is also very limited. For the safety of workers, it is necessary to design a device that uses a mobile robot that can inspect curved pipes. This paper presents the design and construction of a small device that can generate the necessary contact forces between ultrasonic sensors and pipe walls in a limited space. And a mobile robot is used in place ortho worker for successful non-destructive examination.