• 한국정보디스플레이학회:학술대회논문집
• /
• 2000.01a
• /
• pp.85-87
• /
• 2000

In this study, high-density plasma etching characteristics of ITO(indium tin oxide) films used for transparent electrodes in display devices have been investigated. The etch characteristics of ITO as a function of $Ar/CH_4$ gas mixtures were analyzed using QMS(quadrupole mass spectrometry), OES(optical emission spectroscopy), and ESP(electrostatic probe). ITO etch rates were increased with the addition of moderate amount of $CH_4$ to Ar due to the increased chemical reaction between $CH_3$ or H and ITO in addition to the physical sputtering of ITO by Ar ion bombardment. However, the addition of excess amount of $CH_4$ decreased the ITO etch rates possibly due to the increased polymer formation on the ITO surface. Also, the measurement data obtained by QMS and OES suggested that $CH_3$ radicals are more activity involved in the etching of ITO compared to H radicals.

• Journal of the Korean Ceramic Society
• /
• v.50 no.5
• /
• pp.348-352
• /
• 2013

The evaluation of plasma resistance and the characteristics of yttria ceramics fabricated by calcination yttria as a starting material without dopants under an oxidation atmosphere was investigated. Regardless of the starting materials, as-received, and calcined yttria powder, XRD patterns showed that all samples have $Y_2O_3$ phase. The three cycling process inhibited a large grain, which occurs frequently during the yttria sintering, and a high density ceramic with a homogeneous grain size was obtained. The grain size of the sintered ceramic was affected by the starting powders. The smaller the grain size, the larger were the Young's modulus and KIC. Compared to $Al_2O_3$ and $ZrO_2$ ceramics, yttria ceramics showed a 3 times larger plasma resistance and a 1.4~2.2 times lower weight loss during the plasma etching test, respectively.

• Proceedings of the KIEE Conference
• /
• 1998.07e
• /
• pp.1840-1842
• /
• 1998

Gyroscope is a very important core sensor, as a rotation sensor in inertial space, in inertial guidance and navigation system on aeronautics, plane, vessel and so on for civilian and millitary applications. Mechnical gyroscopes, adopting a principle of spinning a top, have been used in many application system. These mechnical gyroscopes need high power consumption, long warming time and complicated peripheral devices. But fiber-optic gyroscopes, based on the Sagnac effect, have novel advantages as small volume. simple scheme, low power consumption and high reliability. So we have developed a Intermediate grade All-fiber Optic Gyroscope, which has open-loop and minimum reciprocal configuration scheme. We have designed feedback circuits for stability of amplitude and phase using four lock-in amplifier(LIA) circuits and also used for noise limitation. This paper describes the scheme of optical part and electronic part and also test results of this all-fiber optic gyroscope. The performance have been achieved as long-term bias drift of $9.54^{\circ}/h$, random walk of $0.0317^{\circ}/\sqrt{h}$ and dynamic range of ${\pm}150\;deg/s$.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.22 no.3
• /
• pp.68-76
• /
• 1985

A charge-coupled device (CCD) area image sensor has been demonstrated with an experi-mental 16$\times$16 prototype. The prototype is a vertical frame transfer charge.coupled imager using two-phase gate electrode structures. In this device, ion-implanted barriers are used for two -phase CCD, and NMOS process has been adopted. The total imaging setup consisting of optical lens, clock generators, clock drivels, staircase signal generators, and oscilloscope is easily achieved with the aid of PROM . English alphabets are displayed on the oscilloscope screen using the total imaging set-up. We measure charge transfer inefficiency and dark current for the fabricated devices.

• Journal of Magnetics
• /
• v.10 no.2
• /
• pp.66-70
• /
• 2005

The junction properties between the ferromagnet (FM) and two-dimensional electron gas (2DEG) system are crucial to develop spin electronic devices. Two types of 2DEG layer, InAs and GaAs channel heterostructures, are fabricated to compare the junction properties of the two systems. InAs-based 2DEG layer with low trans-mission barrier contacts FM and shows ohmic behavior. GaAs-based 2DEG layer with $Al_2O_3$ tunneling layer is also prepared. During heat treatment at the furnace, arsenic gas was evaporated and top AlAs layer was converted to aluminum oxide layer. This new method of forming spin injection barrier on 2DEG system is very efficient to obtain tunneling behavior. In the potentiometric measurement, spin-orbit coupling of 2DEG layer is observed in the interface between FM and InAs channel 2DEG layers, which proves the efficient junction property of spin injection barrier.

• Proceedings of the KSR Conference
• /
• 2009.05a
• /
• pp.831-839
• /
• 2009

An interlocking equipment of railway signalling systems is manufactured with electrical devices and electrical interlocking equipment has been substituted for existing interlock equipment(relay sequential logic type). But interlock conditions are still generated from rail diagram and used to make Interlock Table manually. In order to make EIS(Electrical Interlock System) operate, we should write interlock data which is made from interlock table. But, as the station is larger and more complicated, handwork may becomes a very tediou work and makes more mistakes. Therefore the development of CAD system for Interlocking System is very significant, if CAD can reduce the mistakes from handwork and help the configuring the interlocking system. In this paper, we first arrange some rules which can be used to extract route information automatically from rail diagram and interlocking rules. And then we propose "Search-And-Rollback" algorithm to extract route information and individual interlocking rules. The proposed algorithm is implemented and tested through the signal design process of the Hyundai-Steel private railway to carry melted pig iron from the blast furnace to the steel-making workshop. some cases. It shows that CAD for Interlocking system is very helpful in time saving aspect and system reliability.

• Bulletin of the Korean Chemical Society
• /
• v.28 no.8
• /
• pp.1389-1395
• /
• 2007

Two series of new organic fluorophores such as asymmetrical 3-(benzimidazol-2-yl)-10-hexylphenothiazine derivatives 1 and symmetrical 3,7-bis(benzimidazol-2-yl)-10-hexylphenothiazine derivatives 2 have been synthesized. Electronic absorption, fluorescence, and electrochemistry measurements reveal that the electron withdrawing benzimidazole subunit directly connected to the phenothiazine core facilitates the charge transfer characters which were also verified by the theoretical calculations. Various substituents on the benzimidazole moieties can allow a fine-tuning of the LUMO energy levels of the molecules without significantly affecting the HOMO energy levels. The method provides a new route for designing ambipolar molecules whose energy levels are well-matched with the Fermi levels of the electrodes to facilitate the electron or hole injection/transfer in OLED devices.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.11
• /
• pp.3253-3256
• /
• 2013

Lithium is a highly attractive material for high-energy-concentration batteries, since it has low weight and high potential. Rechargeable lithium-ion batteries (LIBs), which have the extremely high gravimetric and volumetric energy densities, are currently the most preferable power sources for future electric vehicles and various portable electronic devices. In order to improve the efficiency and lifetime, new electrode compounds for lithium intercalation or insertion have been investigated for rechargeable batteries. Solid-state nuclear magnetic resonance (NMR) is a very useful tool to investigate the structural changes in electrode materials in actual working lithium-ion batteries. To detect the in-situ microstructural changes of electrode and electrolyte materials, $^7Li-^{19}F$ double-resonance solid-state NMR probe with a static solenoidal coil for a 600-MHz narrow-bore magnet was designed, constructed, and tested successfully.

• Journal of Power System Engineering
• /
• v.4 no.1
• /
• pp.45-50
• /
• 2000

Circuit breakers have traditionally employed mechanical methods to interrupt excessive currents. According to power semiconductor technology advances in power electronic device, some mechanical breakers are replaced with solid state equivalents. Advantages of the contactors using semiconductor devices include faster fault interrupting, fault current limiting, no arc to contain or extinguish and intelligent power control, and high reliability. This paper describes the design of a static $100{\pm}10%V$ and 0 to 50A DC self-protected contactor with 85A "magnetic tripping" and 100A interruption current at $2.2A/{\mu}s$ short circuit of load condition using a new power device the HARRIS MCT (600V-75A). The self-protection circuit of this system is designed by the classical ZnO varistor for energy absorption and turn-off snubber circuit ("C" or "RCD") of the MCT.

• Journal of the Korean Chemical Society
• /
• v.61 no.1
• /
• pp.12-15
• /
• 2017

We presented a mapping the work function of the vanadium pentoxide ($V_2O_5$) nanonet structures by scanning Kelvin probe microscopy (SKPM). In this measurement, the $V_2O_5$ nanonet was self-assembled via dropping the solution of $V_2O_5$ nanowires (NWs) onto the $SiO_2$ substrate and drying the solvent, resulting in the networks of $V_2O_5$ NWs. We found that the SKPM signal as a surface potential of $V_2O_5$ nanonet is attributed to the contact potential difference (CPD) between the work functions of the metal tip and the $V_2O_5$ nanonet. We generated the histograms of the CPD signals obtained from the SKPM mapping of the $V_2O_5$ nanonet as well as the highly ordered pyrolytic graphite (HOPG) which is used as a reference for the calibration of the SKPM tip. By using the histogram peaks of the CPD signals, we successfully estimated the work function of ~5.1 eV for the $V_2O_5$ nanonet structures. This work provides a possibility of a nanometer-scale imaging of the work function of the various nanostructures and helps to understand the electrical characteristics of the future electronic devices.