• Title/Summary/Keyword: Material Derivative

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Emission Properties of Europium Complex Utilizing Multilayer Quantum-Well Structure Properties by Vacuum Vapor Deposition Method (진공증착법으로 제작한 다층 구조의 Europium Complex의 발광특성)

  • 이상필;이제혁;이한성;김영관;김정수
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.05a
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    • pp.609-612
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    • 1999
  • Organic electroluminescent(EL) devices have received a great deal of attention due to their potential application as full-color displays. They are attractive because of their capability of multicolor emission, ease of fabrication, and operation at a low driving voltage. In this study, single and multiple quantum-well structures consisting of Eu(TTA)$_3$(bpy) complex well layer sandwiched between triphenyldiamine derivative (TPD) layers were fabricated and their photoluminescent electroluminescent characteristics were also investigated. Sharp emission at 616 nm has been observed from the Eu complex in multilayer, single and multiple quantum-well structures. Details on the explanation of electrical properties of these structures will be discussed.

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Electron Transport in Stilbenquinone Derivative-Doped Polymer (Stilbenquinone 유도체가 도핑된 고분자의 전자 수송)

  • 조종래;정재훈;문정오;양종헌;손세모;김강언;정수태
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11a
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    • pp.378-381
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    • 2001
  • The electron drift mobility of poly(4,4'-cyclohexylidenediphenyl carbonate)(PC-Z) doped with 3,5-dimethy-3,5-di-t-butylstilbenequinone(MBSQ), 3,5,3,5-tetra-t-butyl stilbenequinone(TMSQ) and 3,5,3,5-tetra-methyl stilbenequinone(TMSQ) was measured by the time-of-flight technique. The electric field and temperature dependences of the electron drift mobility were discussed with Poole-Frenkel, Arrhenius formulations and non-Arrhenius type of temperature dependence. It was assumed that the hopping sites were Gaussian distribution. Mobility and activation energy of MBSQ were increased with increasing dopant. However, mobilities and activation energy of TBSQ and TMSQ were increased and decreased, respectively.

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Study on Optical Characteristics of 8-Hydroxyquinoline Synthesized Derivative as Sensing Material of the Fiber-Optic Copper Ion Sensor in Aqueous Environment (수질환경에서 광섬유 센서의 구리 이온 감지 물질로서 8-Hydroxyquinoline 합성유도체의 광학적 반응 특성 연구)

  • Kim, Beom Kyu;Park, Byung Gi
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.12
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    • pp.100-105
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    • 2017
  • An 8-hydroxyquinoline compound that was synthesized with 8-hydroxyquinoline-2-carboxaldehyde and 4-aminoantipyrine was investigated for use as the sensing material of a fiber-optic copper ion sensor in an aqueous environment. The experiment was conducted with a fiber-optic measurement system, in order to evaluate the relationship between the absorbance peak and copper ion concentration. The synthesized derivative exhibited a (highly selective) chromogenic phenomenon for copper ions among various metal ions in an aqueous environment and showed a specific absorbance peak at a wavelength of 530 nm for copper ions. The effect of mercury ions was investigated to evaluate the selectivity of the prepared synthesized derivatives toward Cu ions. The absorbance was measured at various concentration ratios of Cu and Hg ions (Cu:Hg ratios from 0.05 to 20), and it was found that the absorbance at 530 nm tended to increase with increasing Cu ion concentration. The experimental results also showed the linear relationship between the logarithmic concentration of copper ions and the specific absorbance peak at a wavelength of 530 nm. These results indicate that the synthesized 8-hydroxyquinoline compound has selectivity for copper ions and can be used as a sensing material for fiber-optic copper ion sensors.

Analysis of Surface Tracking of Micro and Nano Size Alumina Filled Silicone Rubber for High Voltage AC Transmission

  • Loganathan, N.;Chandrasekar, S.
    • Journal of Electrical Engineering and Technology
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    • v.8 no.2
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    • pp.345-353
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    • 2013
  • This paper discusses the experimental results in an effort to understand the tracking and erosion resistance of the micro and nano size $Al_2O_3$ filled silicone rubber (SIR) material which has been studied under the AC voltages, with ammonium chloride as a contaminant, as per IEC 60587 test procedures. The characteristic changes in the tracking resistance of the micro and nano size filled specimens were analyzed through leakage current measurement and the eroded masses were used to evaluate the relative erosion and tracking resistance of the composites. The fundamental, third and fifth harmonic of the leakage current during the tracking study were analyzed using moving average current technique. It was observed that the harmonic components of leakage current show good correlation with the tracking and erosion resistance of the material. The thermogravimetry-derivative thermo gravimetric (TG-DTG) studies were performed to understand the thermal degradation of the composites. The physical and chemical studies were carried out by using scanning electron microscope (SEM), Energy Dispersive X-ray analysis (EDAX) and Fourier Transform Infra-red (FTIR) Spectroscopy. The obtained result indicated that the performance of nano filled SIR was better than the micro filled SIR material when the % wt. of filler increased.

Creep strain modeling for alloy 690 SG tube material based on modified theta projection method

  • Moon, Seongin;Kim, Jong-Min;Kwon, Joon-Yeop;Lee, Bong-Sang;Choi, Kwon-Jae;Kim, Min-Chul
    • Nuclear Engineering and Technology
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    • v.54 no.5
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    • pp.1570-1578
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    • 2022
  • During a severe accident, steam generator (SG) tubes undergo rapid changes in the pressure and temperature. Therefore, an appropriate creep model to predict a short term creep damage is essential. In this paper, a novel creep model for Alloy 690 SG tube material was proposed. It is based on the theta (θ) projection method that can represent all three stages of the creep process. The original θ projection method poses a limitation owing to its inability to represent experimental creep curves for SG tube materials for a large strain rate in the tertiary creep region. Therefore, a new modified θ projection method is proposed; subsequently, a master curve for Alloy 690 SG material is also proposed to optimize the creep model parameters, θi (i = 1-5). To adapt the implicit creep scheme to the finite element code, a partial derivative of incremental creep with respect to the stress is necessary. Accordingly, creep model parameters with a strictly linear relationship with the stress and temperature were proposed. The effectiveness of the model was validated using a commercial finite element analysis software. The creep model can be applied to evaluate the creep rupture behavior of SG tubes in nuclear power plants.

Analysis of the Characteristics of a White OLED using the Newly Synthesized Blue Emitting Material nitro-DPVT by Varying the Doping Concentrations of Fluorescent Dye and the Thickness of the NPB Layer (신규 합성한 청색발광재료 nitro-DPVT를 사용한 백색 유기발광다이오드의 형광색소 도핑농도 및 NPB 층의 두께 변화에 따른 특성 분석)

  • Jeon, Hyeon-Sung;Cho, Jae-Young;Oh, Hwan-Sool;Yoon, Seok-Beom
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.19 no.4
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    • pp.379-385
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    • 2006
  • A stacked white organic light-emitting diode (OLED) having a blue/orange emitting layer was fabricated by synthesizing nitro-DPVT, a new derivative of the blue-emitting material DPVBi on the market. The white-emission of the two-wavelength type was successfully obtained by using both nitro-DPVT for blue~emitting material, orange emission as a host material and Rubrene for orange emission as a guest material. The basic structure of the fabricated white OLED is glass/ITO/NPB$(200{\AA})$/nitro-DPVT$(100{\AA})$/nitro-DPVT:$Rubrene(100{\AA})/BCP(70{\AA})/Alq_3(150{\AA})/Al(600{\AA})$. To evaluate the. characteristics of the devices, firstly, we varied the doping concentrations of fluorescent dye Rubrene from 0.5 % to 0.8 % to 1.3 % to 1.5 % to 3.0 % by weight. A nearly pure white-emission was obtained in CIE coordinates of (0.3259, 0.3395) when the doping concentration of Rubrene was 1.3 % at an applied voltage of 18 V. Secondly, we varied the thickness of the NPB layer from $150{\AA}\;to\;200{\AA}\;to\;250{\AA}\;to\;300{\AA}$ by fixing doping with of Rubrene at 1.3 %. A nearly pure white-emission was also obtained in CIE coordinates of (0.3304, 0.3473) when the NPB layer was $250-{\AA}$ thick at an applied voltage of 16 V. The two devices started to operate at 4 V and to emit light at 4.5 V. The external quantum efficiency was above 0.4 % when almost all of the current was injected.

Effect of the variable visco-Pasternak foundations on the bending and dynamic behaviors of FG plates using integral HSDT model

  • Hebali, Habib;Chikh, Abdelbaki;Bousahla, Abdelmoumen Anis;Bourada, Fouad;Tounsi, Abdeldjebbar;Benrahou, Kouider Halim;Hussain, Muzamal;Tounsi, Abdelouahed
    • Geomechanics and Engineering
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    • v.28 no.1
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    • pp.49-64
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    • 2022
  • In this work, the bending and dynamic behaviors of advanced composite plates resting on variable visco-Pasternak foundations are studied using a simple shear deformation integral plate model. The research is carried out with a view to a three-parameter foundation including the influences of the variable Winkler coefficient, the constant Pasternak coefficient and the damping coefficient of the elastic medium. The present theory uses a displacement field with integral terms instead of derivative terms by including also the shear deformation effect without introducing the shear correction factors. The equations of motion for advanced composite plates are obtained using the Hamilton principle. Analytical solutions for the bending and dynamic analysis are deduced for simply supported plates resting on variable visco-Pasternak foundations. Some numerical results are presented to demonstrate the impact of material index, elastic foundation type, and damping coefficient of the foundation, on the bending and dynamic responses of advanced composite plates.

A Study on the System Principle of PID Module Implementation (PID Module 구현 원리 시스템에 대한 연구)

  • 위성동;김태성;최창주;권병무
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.05a
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    • pp.183-192
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    • 1999
  • The derivative equation measured of a ${\Delta}MV=Kp*{(EVn-EVn-1)+\frac{1}{Ki/S}* EVn+(Kd/S)*(2PVn-1-PVn-PVn-1)}$ is used on the machine apparatus of industrial field, but this par doesn\`t able to educate now, because we didn\`t have the implementation device of PID module, so the principle implementation system of the PID Module is manufactured and developed. Through this system, the implementation system of PID Module is practiced with that the SV and the set of P, I, D is set on the derivative equation measured of PID. A things to be known of this experiment result is flow. 1)PID module is known that had to be used with the module of A/D and D/A. 2) In process of PV is approached to the SV to follow Kp, Ti and Td to cause a constant of set value on the $MVp=Kp*EV, MV=\frac{1}{Ki}{\int}EVdt, MVd=Td\frac{d}{dt}EV$, the variable rate of E and Kp, Td, Ti in that table 1 is analysed, is same as flow. (1)If Kp is high, PV is near fast to the SV, but Kp is small, PV is near slowly to the SV. (2)If Ki is shot, PV is close fast to the SV, but Ti is high, PV is close slowly to the SV (3)If Td is high, the variable rate of E press hardly when because it doesn\`t increase, but Td is small, the variable rate of E press not hardly, upper with 1), 2), PID module is supposed that be able to do the A/S and an implementation of that apparatus, and getting a success of aim that an engineer want, on control of temperature, tension, velocity, amount of flow, power of wind end so on, to get the principle of automatic implementation in industrial field with cooperation of A/D and D/A module.

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Data driven inverse stochastic models for fiber reinforced concrete

  • Kozar, Ivica;Bede, Natalija;Bogdanic, Anton;Mrakovcic, Silvija
    • Coupled systems mechanics
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    • v.10 no.6
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    • pp.509-520
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    • 2021
  • Fiber-reinforced concrete (FRC) is a composite material where small fibers made from steel or polypropylene or similar material are embedded into concrete matrix. In a material model each constituent should be adequately described, especially the interface between the matrix and fibers that is determined with the 'bond-slip' law. 'Bond-slip' law describes relation between the force in a fiber and its displacement. Bond-slip relation is usually obtained from tension laboratory experiments where a fiber is pulled out from a matrix (concrete) block. However, theoretically bond-slip relation could be determined from bending experiments since in bending the fibers in FRC get pulled-out from the concrete matrix. We have performed specially designed laboratory experiments of three-point beam bending with an intention of using experimental data for determination of material parameters. In addition, we have formulated simple layered model for description of the behavior of beams in the three-point bending test. It is not possible to use this 'forward' beam model for extraction of material parameters so an inverse model has been devised. This model is a basis for formulation of an inverse model that could be used for parameter extraction from laboratory tests. The key assumption in the developed inverse solution procedure is that some values in the formulation are known and comprised in the experimental data. The procedure includes measured data and its derivative, the formulation is nonlinear and solution is obtained from an iterative procedure. The proposed method is numerically validated in the example at the end of the paper and it is demonstrated that material parameters could be successfully recovered from measured data.

Color Pure and Stable Blue Light Emitting Material Containing Anthracene and Fluorene for OLED

  • Park, Hyun-Tae;Oh, Dae-Hwan;Park, Jong-Won;Kim, Jin-Hak;Shin, Sung-Chul;Kim, Yun-Hi;Kwon, Soon-Ki
    • Bulletin of the Korean Chemical Society
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    • v.31 no.7
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    • pp.1951-1955
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    • 2010
  • A new blue light emitting anthracene derivative, 9,10-bis-(9',9'-diethyl-7'-t-butyl-fluoren-2'-yl)anthracene (BETF), has been designed and synthesized by a palladium catalyzed Suzuki cross-coupling. A theoretical calculation of the three-dimensional structure of BETF supports that it has a non coplanar structure and inhibited intermolecular interactions resulting in high luminescent efficiency and high color purity. BETF has good thermal stability with glass-transition temperature (Tg) of $131^{\circ}C$. The PL maximum of BETF in solution and film were 438 nm and 440 nm, respectively, showing pure blue emission. A multilayer device using BETF as emitting material exhibits maximum luminescence efficiency of 2.2 cd/A and a pure blue emission (Commission Internationale de L'Eclairage (CIE) coordinates of x = 0.15, y = 0.10).