• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.44-44
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• 2009

Recently, transparent ZnO-based TFTs have attracted much attention for flexible displays because they can be fabricated on plastic substrates at low temperature. We report the fabrication and characteristics of ZnO channel layers(ZnO TFTs) having different channel thicknesses. The ZnO film were deposited as active channel layers on $Si_3N_4/Ti/SiO_2p$-Si substrates by rf magnetron sputtering at $100\;^{\circ}C$ without additional annealing. Also the Zno thin films deposited at oxygen partial pressures of 40%. ZnO TFTs using a bottom-gate configuration were investigated. The $Si_3N_4$ film were deposited as gate insulator by PE-CVD at $15\;^{\circ}C$. All Processes were processed below $150^{\circ}C$ which is optimal temperature for flexible display and were used dry etching method.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.10
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• pp.821-825
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• 2009

Recently, transparent ZnO-based TFTs have attracted much attention for flexible displays because they can be fabricated on plastic substrates at low temperature. We report the fabrication and characteristics of ZnO TFTs having different channel thicknesses deposited at low temperature. The ZnO films were deposited as active channel layer on $Si_3N_4/Ti/SiO_2/p-Si$ substrates by RF magnetron sputtering at $100^{\circ}C$ without additional annealing. Also, the ZnO thin films deposited at oxygen partial pressures of 40%. ZnO TFTs using a bottom-gate configuration were investigated. The $Si_3N_4$ film was deposited as gate insulator by PE-CVD at $150^{\circ}C$. All Processes were processed below $150^{\circ}C$ which is optimal temperature for flexible display and were used dry etching method. The fabricated devices have different threshold slop, field effect mobility and subthreshold slop according to channel thickness. This characteristics are related with ZnO crystal properties analyzed with XRD and SPM. Electrical characteristics of 60 nm ZnO TFT (W/L = $20\;{\mu}m/20\;{\mu}m$) exhibited a field-effect mobility of $0.26\;cm^2/Vs$, a threshold voltage of 8.3 V, a subthreshold slop of 2.2 V/decade, and a $I_{ON/OFF}$ ratio of $7.5\times10^2$.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2008.05a
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• pp.23-29
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• 2008

- High Density Plasma Source-CCP-Dual/Triple, RF Frequency Control - Radical/Flux Analysis - Low Pressure Process - Chamber Design (Process gap/Wall gap) - Chamber Temp. Control. - ESC Dielectric Materials - Uniform Gas Injection

• Journal of Korean Society on Water Environment
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• v.26 no.1
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• pp.96-103
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• 2010

In this work, the presence of nitrification biochemical oxygen demand (NBOD) frequently occurred in the sewer outflow in winter season was analysed by the COD fraction methods using the respirometry and process simulations with real operation data measurements and analysis. The activated sludge models applied in this process simulation were based on the ASM No.2d temp. models, published by International Association on Water Quality (IAWQ). The ASM No.2d model is an extension of the ASM No.2 model and takes into account of carbon removal, nitrification, denitrification and phosphorus removal. The denitrifying capacity of phosphorus accumulating organisms has been implemented in the ASM No.2d model because experimental evidence shows that some of the phosphorus accumulating organisms can denitrify. It was shown that the concentrations of autotrophs (X_AUT) in the secondary clarifier and the $NH_4-N$ of T-N increased in the presence of NBOD measurements. Because of the low temperature (average $8^{\circ}C$) and possible operational troubles, the outcoming autotrophs exhausted oxygen in the process of nitrifying $NH_4-N$.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.2
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• pp.191-197
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• 2005

A new method, ToxTemp (TOXcity test based on TEMPerature control) using Ceridaphnia dubia was applied to evaluate the toxicity of insecticide materials and compared with the standard 48 hr acute bioassay. BPMC, diazinon and fenitrothion may cause the inhibition to the biological process in sewage treatment plant and need to detect toxicity within short contact time. The ToxTemp method showed sensitive detection with more shorter contact of 1-1.5 hr time than that of the standard 48 hr acute bioassay. To evaluate toxicity of real wastewater/sewage, the inhibition rate of nitrification and oxygen uptake rate (OUR) using activated sludge, the standard 48hr acute bioassay and ToxTemp method using C. dubia were compared, respectively. On the basis of the inhibition rate of nitrification, the OUR test showed the less sensitive results at the relatively strong toxic sewage. On the other hands, the standard 48hr acute bioassay and ToxTemp method using C. dubia represented the toxicity of each wastewater/sewage with high sensitivity. Even the slightly low (about 1.5%) sensitivity, the ToxTemp method showed the high applicability to the real site of sewage treatment plant.

• Korean Chemical Engineering Research
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• v.59 no.4
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• pp.611-625
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• 2021

Mg crowns were manufactured using domestic dolomite (Ca·Mg(CO₃)₂) (20~30 mm). In order to manufacture the calcined dolomite (CaO·MgO), (a) electric furnace (950 ℃, 480 min) and (b) microwave furnace (950 ℃, 60 min) processes were used. As a result of XRD analysis, it was analyzed as (a) CaO 56.9 wt%, MgO 43.1 wt% by electric furnace process and (b) CaO 55 wt%, MgO 45 wt% by microwave furnace process. Even when the decarbonation reaction time of dolomite was shortened by 1/8 in microwave furnace process compare with electric furnace process, the calcined dolomite could be produced. The hydration reaction (ASTM C 110) is a standard for the hydration reactivity of calcined dolomite, and the calcined dolomite produced by electric furnace process showed a high hydration reactivity (max temp 79.8 ℃/1.5 minutes). Such hydration reactivity was occurred by only CaO hydration reaction and that was confirmed by XRD analysis. The calcined dolomite produced by microwave furnace process showed low hydration reactivity (max temp 81.7 ℃/19.5 minutes). Such low hydration reactivity was occurred by CaO and MgO hydration reaction due to the hydration reaction of CaO thereafter occurring of the hydration reaction of MgO, and that was confirmed by XRD analysis. The prepared Mg crown were 58.8 g and 74.6 g by electric furnace and microwave furnace processes, respectively, under the reaction conditions of 1,230 ℃, 60 min, 5 × 10^-2 torr by silicothermic reduction.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.10a
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• pp.193-197
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• 2002

Polyurethane casting wing fairings included in F-5E/F 15% spar kit are to be installed on aircraft wing surfaces and used for compensating the changes of the aerodynamic configuration by the leading edge extension fairings. These fairing are mandatory items in repairing wing areas and was imported from foreign supplier with long term delivery and high cost. Accordingly, local manufacturing is necessary to get rid of above disadvantages such as long term delivery and high cost. Basic properties test of specimen to be developed and part's requirements after localization was taken and its values were similar or higher when comparing with the original's even in low temp test at -55C. Casting mold process was used to manufacture the polyurethane fairings and its demensional stability ＆ physical condition was proper and met to the related specification and drawing's requirements

• Journal of the Korea Institute of Military Science and Technology
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• v.23 no.5
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• pp.523-531
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• 2020

Extraction and anti-solvent crystallization were proposed to recover octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) from pressed polymer bonded explosives(PBXs). DXC-57 and DXC-59, whose polymeric binders are Estane and HyTemp with dioctyl adipate plasticizer, respectively, were used as pressed PBX models. Estane of DXC-57 was removed by washing with tetrahydrofuran prior to extraction, which enabled the crystallization of HMX at a low degree of supersaturation, sufficient to obtain β-form HMX. Using dimethyl sulfoxide and ethanol as the extraction solvent and the anti-solvent for crystallization, respectively, HyTemp and dioctyl adipate in DXC-59 were separated from HMX. The purity of recovered β-form HMX was higher than 99 %.

• Journal of the Korea Society of Computer and Information
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• v.24 no.11
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• pp.21-27
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• 2019

Recently, embedded systems have been introduced in various fields such as smart factories, industrial drones, and medical robots. Since sensor data collection and IoT functions for machine learning and big data processing are essential in embedded systems, it is essential to port the operating system that is suitable for the function requirements. However, in embedded systems, it is necessary to separate the hard real-time system, which must process within a fixed time according to service characteristics, and the flexible real-time system, which is more flexible in processing time. It is difficult to port the operating system to a low-performance embedded device such as 8BIT MCU to perform simultaneous real-time. When porting a real-time OS (RTOS) to a low-specification MCU and performing a number of tasks, the performance of the real-time and general processing greatly deteriorates, causing a problem of re-designing the hardware and software if a hard real-time system is required for an operating system ported to a low-performance MCU such as an 8BIT MCU. Research on the technology that can process real-time processing system requirements on RTOS (ported in low-performance MCU) is needed.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.279-281
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• 1997

The properties of Platinum dry etching were investigated in MICP(Magnetized Inductively Coupled Plasma). The problem with Platinum etching is the redeposition of sputtered Platinum on the sidewall. Because of the redeposits on the sidewall, the etching of patterned Platinum structure produce feature sizes that exceed the original dimension of the PR size and the etch profile has needle-like shape.[1] Generally, $Cl_2$ plasma is used for the fence-free etching.[1][2][3] The main object of this study was to investigate a new process technology for the fence-free Pt etching. Platinum was etched with Ar plasma at the cryogenic temperature and with Ar/$SF_6$ plasma at room temperature. In cryogenic etching, the height of fence was reduced to 20% at $-190^{\circ}C$ compared with that of room temp., but the etch profile was not fence-free. In Ar/$SF_6$ Plasma, chemical reaction took part in etching process. The trend of properties of Ar/$SF_6$ Plasma etching is similar to that of $Cl_2$ Plasma etching. Fence-free etching was possible, but PR selectivity was very low. A new gas chemistry for fence-free Platinum etching was proposed in this study.