• Journal of Korean Vacuum Science & Technology
• /
• 제6권3호
• /
• pp.126-132
• /
• 2002

The origin of image-sticking in metal-insulator-metal type thin-film diode liquid crystal displays(TFD-LCDs) is the asymmetric current-voltage(I-V) characteristic of TFD element. We developed that TFD-LCDs have reduced-image-sticking. Tantalum pentoxide(Ta$_2$O$\sub$5/) is a candidate for use in metal-insulator-metal(MIM) capacitors in switching devices for active-matrix liquid crystal displays(AM-LCDs). High quality Ta$_2$O$\sub$5/ thin films have been obtained from anodizing method. We fabricated a TFD element using Ta$_2$O$\sub$5/ films which had perfect current-voltage symmetry characteristics. We applied novel process technologies which were postannealed whole TFD element instead of conventional annealing to the fabrication. One-Time Post-Annealing(OPTA) heat treatment process was introduced to reduce the asymmetry and shift of the I-V characteristics, respectively. OPTA means that the whole layers of lower metal, insulator, and upper metal are annealed at one time. Futhermore, in this paper, we discussed the effects of top-electrode metals and annealing conditions.

• 항공우주기술
• /
• 제8권1호
• /
• pp.58-65
• /
• 2009

본 논문은 검출기의 포화과정을 반영한 비선형 모델의 잡음 특성을 분석하고, 그러한 분석결과를 영상 신호-잡음비(Image SNR)의 분포도를 계산하기위하여 적용한다. 특별히, 검출 화소의 비선형성은 잡음분포(PDF)의 비대칭성과 화소 신호-잡음비(Pixel SNR)의 증폭이라는 두 가지 관점에서 분석되며, 제안된 영상 신호-잡음비 분포도를 이용하여 위성의 발사 후에 카메라 이득의 변화나 기타 상황에서도, 궤도상에서 최적의 위성 카메라 운영 변수들(노출시간, 누적횟수)을 얻을 수 있음이 주요한 특징으로 강조된다.

• Asia pacific journal of information systems
• /
• 제13권2호
• /
• pp.119-143
• /
• 2003

Trust has been identified as a key component in many e-Commerce studies. The purpose of this study is to find out which factors play a major role in building trust and how the built-up trust affect consumer's purchase intention in Internet used-car transactions. Based on the information asymmetry, TAM(Technology Acceptance Model), and the trust theory, our research model includes factors such as a buyer's propensity-to-trust, institutional characteristics(inspection and warranty policy), word-of-mouth referral, perceived size, and perceived benefits as independent variables. The model also includes trust as a mediate variable, intention to purchase as a dependent variable and perceived quality risk as a moderate variable. The research model is tested by analyzing 787 sample data gathered from Internet used-car transaction sites. The result shows that the trust has significant effects on the online purchase intention, and institutional characteristics has been identified as the most significant factor for the trust of Internet used-car sites. The independent factors influencing trust vary depending on the level of perceived quality risk. For users who perceive the quality risk low, the perceived benefits explain a little portion of the purchase intention. However, those who perceive quality risk high would purchase used-cars only when they have trust on the Internet sites, indicating that trust play an important role as a mediate variable. This study suggests that enhancing the trust in Internet used-car sites is important to increase online transactions.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제13권5호
• /
• pp.473-481
• /
• 2013

A fractional folding analog-to-digital converter (ADC) with a novel arithmetic digital encoding technique is discussed. In order to reduce the asymmetry errors of the boundary conditions for the conventional folding ADC, a structure using an odd number of folding blocks and fractional folding rate is proposed. To implement the fractional technique, a new arithmetic digital encoding technique composed of a memory and an adder is described. Further, the coding errors generated by device mismatching and other external factors are minimized, since an iterating offset self-calibration technique is adopted with a digital error correction logic. A prototype 8-bit 1GS/s ADC has been fabricated using an 1.2V 0.13 um 1-poly 6-metal CMOS process. The effective chip area is $2.1mm^2$(ADC core : $1.4mm^2$, calibration engine : $0.7mm^2$), and the power consumption is 88 mW. The measured SNDR is 46.22 dB at the conversion rate of 1 GS/s. Both values of INL and DNL are within 1 LSB.

• 소성∙가공
• /
• 제14권2호
• /
• pp.160-167
• /
• 2005

In the present study about extru-bending of angle product, the bending of extruded angle products with the $'\Lambda'$ section and 'ㄱ', section can be obtained using two extrusion billets by the hot metal extru-bending machine with the two punches moving in the different velocity. The bending curvature can be controlled by the different velocity of billets through the two-hole container. This paper describes simulations and experiments of extru-bending process that can make bending during extruding by the difference of stem velocities. And they are applied to two kinds of dies, that is, one of them is conical dies with symmetry $'\Lambda'$ section and the other one is conical dies with asymmetry 'ㄱ' section. The results of the forming simulation by $DEFORM^{TM}-3D$ and results of experiments show that the bending phenomenon at the die exit during extrusion can be obtained with two extrusion billet by the two stems moving in the different velocity. And it was known that it is possible to design the structure of conical cavity of extrusion dies and to control the curvature of product through the simulation and experiment of extru-bending process.

• Journal of Mechanical Science and Technology
• /
• 제14권12호
• /
• pp.1386-1395
• /
• 2000

The mear field structure of round turbulent jets with initially asymmetric velocity distributions is investigated experimentally. Experiments are carried out using a constant temperature hot-wire anemometry system to measure streamwise velocity in the jets. The measurements are undertaken across the jet at various streamwise stations in a range starting from the jet exit plane and up to a downstream location of twelve diameters. The experimental results include the distributions of mean and instantaneous velocities, vorticity field, turbulence intensity, and the Reynolds shear stresses. The asymmetry of the jet exit plane was obtained by using circular cross-section pipes with a bend upstream of the exit. There pipes used here include a straight pipe, and 90 and 160 degree-bend pipes. Therefore, at the upstream of the upstream of the pipe exit, secondary flow through the bend mean streamwise velocity distribution could be controlled by changing the curvature of pipes. The jets into the atmosphere have two levels of initial velocity skewness in addition to an axisymmetric jet from a straight pipe. In case of the curved pipe, a six diameter-long straight pipe section follows the bend upstream of the exit. The Reynolds number based on the exit bulk velocity is 13,400. The results indicate that the near field structure is considerably modified by the skewness of an initial mean velocity distribution. As the skewness increases, the decay rate of mean velocity at the centerline also increases.

• The Journal of Asian Finance, Economics and Business
• /
• 제7권9호
• /
• pp.39-49
• /
• 2020

This study empirically examines herd behavior for fast moving consumer goods (FMCG) sector stocks under varied market return conditions and the period during the global financial crisis and its aftermath. We examine the sample of stocks trading on the Nifty FMCG Index of the Indian equity market from January 2008 up to December 2018 using the dispersion measure of cross sectional absolute deviation and examine its relationship with the market return to explore herd phenomenon. Quantile regression estimate is used and the results of the study validate rational asset pricing models as the sector does not display herding. In contrast, anti-herd behavior at lower and median quantile values is observed. A possible reason can be the non-cyclical nature of the industry where investors rely more on the fundamentals rather than crowd chasing. We also findthe absence of herd phenomenon during the market asymmetries of bull and bear phases, extreme movements, the period of the global financial crisis, and afterward. We further examine herding under the impact of the information technology (IT) industry and conclude that significant return movements in IT sector impact dispersions in the FMCG industry. Also, there is a co-varying risk between the two sectors confirming the spillover in an integrated market.

• The Journal of Asian Finance, Economics and Business
• /
• 제7권9호
• /
• pp.293-304
• /
• 2020

The study reveals the extent of changes in selective financial numbers caused by fixed asset revaluation (FAR) and explores whether there was a management motive for playing the financial numbers game through using the FAR model. The data set consists of a sample of 142 listed companies purposively selected from 13 industries. The study found a significant impact of FAR on the net asset value (NAV), fixed asset intensity (FAI), and debt-to-equity ratio (DER). These findings are supported by the political cost and the debt covenant hypotheses. The study also observed a high growth of fixed assets by 9.5% to 14,603.8% resulting from FAR. More revealing is that FAR increased NAV in revaluer companies by an average of 427.20% as compared to 6.86% in non-revaluer companies. Even some companies with negative NAV took resort on FAR to show positive NAV. Besides, revaluer companies managed to reduce their DER by 70.45% as opposed to an increase of 8.45% in non-revaluer companies. Hence, the study concludes that most of the publicly-listed companies are involved in financial numbers game by the use of the FAR model. To build confidence among investors, companies should practice FAR rightly and disclose related information to help reduce information asymmetry.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제50권11호
• /
• pp.581-588
• /
• 2001

This paper presents theoretical and experimental study on the quality-factor of the laterally oscillated electrostatic microactuator, driven by a lateral repulsive-force generated by the asymmetry of planar electric field. The quality-factor of the repulsive-force microactuator using a creeping flow model of the ambient air is evaluated. By filling the simulation results of damping force, we evaluate the dimensionless damping force, $\alpha$, thereby obtaining an analytical damping force, F, in the form of $F=\mu\; \alphaUL,\; where\; \mu,$ U and L denote the air viscosity, the velocity and the characteristic length of the movable electrodes. The measured quality-factor increases from 12 to 13 for the DC bias voltage increased from 60V to 140v. The theoretical quality-factor estimated from the creeping flow model increases from 14.9 to 18.7. Characteristics of quality-factor of the repulsive-force microactuator have been discussed and compared with those of the conventional attractive-force microactuator.

• 소성∙가공
• /
• 제19권5호
• /
• pp.283-289
• /
• 2010

Extrusion process in the bulk material for fabrication of miniature helical gears has problems such as a high forming load and short tool life because the cross-section is complex and asymmetry. To overcome these problems, in this study, miniature helical gears were fabricated by Zn-22Al powder hot extrusion. The included die angle for minimum extrusion load and improving die filling was determined by FE-simulation. The Zn-22Al spheroidal powder produced by gasatomization were compacted and sintered for extrusion experiment. The dimension of helical-gear is 0.3mm in module, 3.35mm in pitch diameter, $15^{\circ}$ in helix angle and the number of teeth is 12. All of the extrusion experiments were performed with internal helical gear die which was machined by precision electric discharge machining using the electrode. The experiment was conducted at $190^{\circ}C$ to $310^{\circ}C$ to obtain extrusive and mechanical properties. The extruded helical gears were analyzed through extrusion load, Vickers hardness and SEM images for each extrusion temperature. The powder hot extrusion process was successfully applied to fabricate a miniature helical gear.