• Journal of Korean Society for Atmospheric Environment
• /
• v.21 no.2
• /
• pp.269-274
• /
• 2005

In this work, analytical bias arising from the gas chromatographic determination of sulfur compounds was evaluated by the application of direct loop injection method to the GC/PFPD detection of four sulfur compounds including H$_{2}$S, CH$_{3}$SH, DMS, and DMDS. For the proper evaluation of analytical uncertainties involved in GC calibration, we employed two comparative techniques of calibration at fxed concentration injection (CFCI) vs calibration at fixed volume injection (CFVI) method. The results of our study indicate that CFCI method exhibits very poor sensitivity due to the matrix effect with varying injection volumes. On the other hand, as CFVI method overcomes such limitation, it can be used to obtain very accurate quantification of S compounds at their high concentration levels above a few to a few tens ppb.

• International Journal of Aeronautical and Space Sciences
• /
• v.1 no.1
• /
• pp.70-80
• /
• 2000

The attitude knowledge error model is formulated for specifically KOMPSAT attitude determination system using the Lefferts/Markley/Shuster method, and the attitude determination(AD) error analysis is performed so as to investgate the on-board attitude determination capability of KOrea Multi-Purpose SATellite(KOMPSAT) using the covariance analysis method. Analysis results show there is almost no initial value effect on Attitude Determination (AD) error and the sensor noise effects on AD error are drastically decreased as is predicted because of the inherent characteristic of Kalman filter structure. However, it shows that the earth radiance effect of IR-sensor(earth sensor) and the bias effects of both IR-sensor and fine sun sensor are the dominant factors degrading AD error and gyro rate bias estimate error in AD system. Analysis results show that the attitude determination errors of roll, pitch and yaw axes are 0.056, 0.092 and 0.093 degrees, respectively. These numbers are smaller than the required values for the normal mission of KOMPSAT. Also, the selected on-orbit data of KOMPSAT is presented to demonstrate the designed AD system.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2008.10a
• /
• pp.319-323
• /
• 2008

"How does advertising affect sales?" is the fundamental issue of modern advertising research. There is an interesting issue for estimating carry over effects of advertising on sales, and the aggregated data biases exist in the duration of advertising effect. This research suggests a modified model at micro-data using Koyck model (Koyck 1954) by estimated model the aggregate data, and empirically shows the aggregated data bias. Our modified model with the aggregated level of actual data is more appropriate than the base model for micro-data. The result shows that it is very important to consider the disaggregated data level in the analysis of dynamic effects of adverting such as lagged effects.

• Journal of Astronomy and Space Sciences
• /
• v.27 no.2
• /
• pp.123-128
• /
• 2010

This paper analyzes that the global positioning system (GPS) receiver differential code bias (DCB) has effect on the estimation the ionosphere total electron content (TEC). The data from nine permanent GPS sites of the Korea Astronomy and Space Science Institute (KASI) were used for the estimation of the receiver DCB before (Trimble 4000 SSi) and after (Trimble NetRS) the receiver replacement, using the singular value decomposition method. The results showed that the estimated mean value of the receiver DCB varied from 0.11 ns (nanosecond) to 7.54 ns before the receiver replacement, but the receiver DCBs shoed large values than 20 ns except some stations after the replacement. The receiver DCB showed a relatively large difference by types of the receivers, and, as a result, it had a great effect on the estimation the ionosphere TEC using GPS.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2007.08b
• /
• pp.1075-1078
• /
• 2007

Negative Bias Temperature Instability (NBTI) in Eximer Laser Annealing (ELA) based Low Temperature polysilicon (LTPS) Thin-Film Transistors (TFT) was investigated. Even though NBTI is generally appeared in devices with thin gate oxide, the TFT with gate oxide thickness of 120 nm, relatively thick, also showed NBTI effect and dynamic NBTI effect is dependent on operational frequency.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2010.03b
• /
• pp.40-40
• /
• 2010

CdSe nanocrystals (NCs) have been decorated on singlewalled carbon nanotubes (SWCNTs) by combining a method of chemically modified substrate along with gate-bias control. CdSe/ZnS core/shell quantum dots were negatively charged by adding mercaptoacetic acid (MAA). The silicon oxide substrate was decorated by octadecyltrichlorosilane (OTS) and converted to hydrophobic surface. The negatively charged CdSe NCs were adsorbed on the SWCNT surface by applying the negative gate bias. The selective adsorption of CdSe quantum dots on SWCNTs was confirmed by confocal laser scanning microscope. The measured photocurrent clearly demonstrates that CdSe NCs decorated SWCNT can be used for photodetector and solar cell that are operable over a wide range of wavelengths.

• Journal of the Semiconductor & Display Technology
• /
• v.14 no.2
• /
• pp.41-45
• /
• 2015

From 20nm technology node, the finFET has become standard device for ULSI's. However, the finFET process made stacking gate non-volatile memory obsolete. Some reported capacitor-less DRAM structure by utilizing the FBE. We present possible non-volatile memory device structure similar to the dual gate MOSFET. One of the gates is left floating. Since body of the finFET is only 40nm thick, control gate bias can make electron tunneling through the floating gate oxide which sits across the body. For programming, gate is biased to accumulation mode with few volts. Simulation results show that the programming electron current flows at the interface between floating gate oxide and the body. It also shows that the magnitude of the programming current can be easily controlled by the drain voltage. Injected electrons at the floating gate act similar to the body bias which changes the threshold voltage of the device.

• Proceedings of the International Microelectronics And Packaging Society Conference
• /
• 2000.04a
• /
• pp.97-102
• /
• 2000

We have studied etching characteristic of Ta film using Electron Cyclotron Resonance (ECR) etcher system. Microwave source power. RF bias power. and working pressure were varied to investigate the etch Profile. And we have used two step etching method to acquire the goWe have studied etching characteristic of Ta film using Electron Cyclotron Resonance (ECR) etcher system. Microwave source power. RF bias power. and working pressure were varied to investigate the etch Profile. And we have used two step etching method to acquire the good etch profile preventing the microloading effect.od etch profile preventing the microloading effect.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.27 no.7
• /
• pp.829-836
• /
• 2003

Understanding of heat generation in semiconductor devices is important in the thermal management of integrated circuits and in the analysis of the device physics. Scanning thermal microscope was used to measure the temperature and the electric potential distribution on the cross-section of an operating metal-oxide-semiconductor field-effect transistor (MOSFET). The temperature distributions were measured both in DC and AC modes in order to take account of the leakage current. The measurement results showed that as the drain bias was increased the hot spot moved to the drain. The density of the iso-potential lines near the drain increased with the increase in the drain bias.

• Journal of Magnetics
• /
• v.16 no.2
• /
• pp.97-100
• /
• 2011

Bilayers of soft NiFe (150 nm-420 nm) on hard Ni (150 nm) were prepared by electrodeposition. The process of magnetization reversal in the NiFe/Ni bilayers was then investigated. The hysteresis loop generated by a magnetization reversal of soft NiFe under a positive saturation state of a hard Ni layer shows a shift along the negative field axis, which is clear evidence for the exchange spring effect in the NiFe/Ni bilayers. The dependence of the coercive field $H_c$ and exchange bias field Hex on the thickness of the NiFe layer was also investigated. As the NiFe thickness increases from 150 nm to 420 nm, both $H_c$ and $H_{ex}$ decrease rapidly from $H_c$= 51.7 Oe and $H_{ex}$ = 12.2 Oe, and saturate to $H_c$ = 5.8 Oe and $H_{ex}$ = 3.5 Oe.