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We are concerned with weak solutions of elliptic equations involving measurable nonlinearities with Orlicz growth to address what would be the weakest regularity condition on the associated nonlinearity for the Calderón–Zygmund theory. We prove that the gradient of weak solution is as integrable as the nonhomogeneous term under the assumption that the nonlinearity is only measurable in one of the variables while it has a small BMO assumption in the other variables. To this end, we develop a nonlinear Moser-type iteration argument for such a homogeneous reference problem with one variable–dependent nonlinearity under Orlicz growth to establish $W^{1,q}$–regularity for every $q>1$. Our results open a new path into the comprehensive understanding of the problem with nonstandard growth in the literature of optimal regularity theory in highly nonlinear elliptic and parabolic equations.

As a matrix resin of silica/epoxy hybrid encapsulation material with high heat resistance and low coefficient of thermal expansion, a tri-functional triglycidyl p-aminophenol (TGPAP) epoxy was successfully synthesized with the desired chemical structure by reacting epichlorohydrin with p-aminophenol using sodium hydroxide catalyst. In order to produce highly pure TGPAP with lower viscosity, a physical thin film vacuum distillation was carried out after synthesis, resulting in 97% purity with the viscosity of 700 cps at room temperature. Silica/TGPAP hybrid was fabricated using two kinds of ground fumed silica with different sizes of 20 μm and 9 μm. Glass transition temperature of the hybrid was found to be as high as 185 °C. Viscosity of the hybrid was 30,000 cps at room temperature before curing, implying good processability. When two different sizes of silica were used with 1 to 1 weight ratio, very low coefficient of thermal expansion of 22.79 ppm/°C was obtained. From thermal shock test, no cracks were observed even after 1,000 cycles of thermal shock between −40 °C and 125 °C when 67 wt% (45.8 vol%) of silica was involved in the hybrid. In conclusion, silica/TGPAP hybrid with improved processability, superior thermal shock resistance and low thermal expansion coefficient could be fabricated as electronic device encapsulation.

Effect of formation of oxidation film on the wear behavior of Alloy 690 steam generator (SG) tubes for nuclear power plants was investigated. Alloy 690 SG tubes are normally oxidized during operation due to the high temperature of the pressurized water. Based on the previous tribology research for metallic materials, we reasoned that the oxidation film can have an important effect on the wear behavior of the Alloy 690 SG tubes. Therefore, in this study, Alloy 690, oxidized in an autoclave under secondary water conditions, was used for wear test. The result of the wear test showed that as the oxidation treatment time increased, the thickness of oxidation film increased and the wear resistance of Alloy 690 increased.

The effect of carbide size and spacing on the fretting wear resistance of Inconel 690 steam generator (SG) tube mated with SUS 409 was investigated in this study. Based on previous materials tribology research, we reasoned that increasing carbide size and spacing would increase the wear resistance of the Inconel 690. Experiments were performed to test this hypothesis. Commercialized Inconel 690 tube with mean carbide length, thickness and spacing of 0.29, 0.10, and 0.59 μm, respectively, was used for the wear test. Carbide length, thickness, and spacing increased to 0.36, 0.15, and 0.68 μm, respectively after heat treatment at 450 °C for 16 h without changes in carbide volume fraction, grain size or hardness. The results of the wear test showed that at the amplitude of 25 μm, wear coefficient did not change due to stick phenomenon. At the amplitude of 50 μm–150 μm, wear coefficient decreased about 50%. At the amplitude of 300 μm, the wear coefficient decreased from 2.7 × 10 − 13 m 3 / Nm to 2.0 × 10 − 13 m 3 / Nm due to increase in carbide size and spacing.

This work was supported by the Human Resource Development program (No. 20114010203020) of a Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korean Government Ministry of Trade, Industry and Energy.

As carbon monoxide oxidation is widely used for various chemical processes (such as methanol synthesis and water-gas shift reactions H

An effect of bilayer cathode Li2O/Al system was studied in Alq3 based organic light-emitting diodes with a variation of Li2O layer thickness from 0 to 10 nm. The device was made in a structure of ITO/(TPD)/Alq3/Li2O/Al. Current density-luminance-voltage (J-L-V) characteristics and a built-in voltage of the device were measured at ambient conditions. Built-in voltage in the device is generated due to a difference of work functions between the anode and cathode. From the J-L-V characteristics of the device, we observed an increase in luminance and current efficiency by more than 100 times and 2 times, respectively, for the device with 0.5 nm thick Li2O layer. The measured built-in voltage shows that the device with 0.5 nm thick Li2O layer has relatively higher built-in voltage compared to the others. Since the higher value of built-in voltage corresponds to the lower value of electron barrier height in cathode, the improvement in the efficiency for the device with 0.5 nm thick Li2O layer is thought to be due to a lowering of the electron barrier height.

Low level laser therapy has various therapy effects, This paper performed the basic study for fabricating the low level laser therapy apparatus, and one of the goals of this paper was to make this apparatus used handily. The apparatus has been fabricated using the laser diode and microprocessor unit. The apparatus used a 660nm, 785nm and 850nm laser diode for laser medical therapy and was designed for a pulse width modulation type to increase stimulation effects. To raise the stimulus effect of the human body, the optical irradiation frequency could be set up. In result, the irradiation frequency could be controlled stably.

We developed the 4channel Light Medical Therapy Apparatus for External Injury Cure using a high brightness LED. This equipment was fabricated using a micro-controller and a high brightness LED, and designed to enable us to control light irradiation time, intensity, frequency and so on, Especially, to control the light irradiation frequency, FPGA was used, and to control the change of output value, TLC5941 was used. Control stage is divided into 4 levels by program. Consequently, the current value could be controlled by the change of level in Continue Wave(CW) and the output of a high brightness LED could be controlled stage by stage. Compared with one LED irradiation, several LEDs irradiation could increase optical power.

Since the first report of the light-emitting diodes based on Alq 3, many organic materials have been synthesized and extended efforts have been made to obtain high performance electroluminescent (EL) device. We synthesized new emissive material, 1, 4-dihydoxy-5, 8-naphtaquinone· Alq 3 complex( Al 2 Nq 4), and extended efforts have been made to obtain high-performance electroluminescent (EL) devices. Current–voltage (I–V) and luminance–voltage (L–V) characteristics were measured by Flat Panel Display Analysis System (Model 200-AT) at room temperature. The Al 2 Nq 4 shows green photoluminescence and electroluminescence spectra at about 510 nm, and ITO/Al 2 Nq 4/Cathode device shows typical rectifying characteristics.

Organic light-emitting diodes were fabricated using Langmuir–Blodgett (LB) technique with new emissive organic material. This new emissive organic material was synthesized and called PECCP [poly(3,6- N -2-ethylhexyl carbazolyl cyanoterephthalidene)], which has strong electron donor group and electron acceptor group in main chain repeated unit. This material has good solubility in common organic solvent and has a good stability in air. We made PECCP LB films and investigated current–voltage ( I – V ) characteristics in ITO/PECCP LB/Al and ITO/PECCP LB/Alq 3 /Al structures, and the Alq 3 was used as an electron transport layer. We have observed that the peak in electroluminescent spectrum of ITO/PECCP LB/Alq 3 /Al device shifts to lower wavelength as the number of LB layer increases. The electroluminescent peaks are at about 507 nm, 505 nm, 503 nm, and 491 nm when the number of LB layers are 5, 7, 9, and 11 layers, respectively. From the I – V characteristics, the barrier height was obtained using Fowler–Nordheim analysis and it is in the range of 0.18 eV–0.26 eV.

It has been a long time since organic solar cells were expected as a low-cost energy-conversion device. Although practical use of them has not been achieved, technological progress continues. Morphology of the materials, organic/inorganic interface, metal cathodes, molecular packing and structural properties of the donor and acceptor layers are essential for photovoltaic response. We have fabricated solar cell devices based on zinc-phthalocyanine(ZnPc) as donor(D) and fullerene as electron acceptor(A) with doped charge transport layers, and BCP and as an exciton blocking layer(EBL). We have measured the photovoltaic characteristics of the solar cell devices using the Xe lamp as a light source. We were use of layer leads to external power conversion efficiency was at illumination intensity . Also we confirmed the optimum thickness ratio of the DA hetero-junction is about 1:2.

This paper shows the application of fuzzy system for a modeling of nonlinear biochemical process. A wastewater treatment process for nitrogen removal in a sequencing batch reactor (SBR) is presented and fuzzy systems with different consequent polynomials in the fuzzy rules to model and identify the oxidation reduction potential (ORP) of the process are introduced. The paper compares, analyzes the results of fuzzy modeling, and shows the nonlinear process can be modeled reasonably well by the present scheme.

Molecular switching devices were reported utilizing Langmuir–Blodgett (LB) monolayer films containing the 5,10,15,20-Tetrakis-Octadecyloxymethylphenyl-Porphyrin-Zn(II) as a redox-active component. From current–voltage (I–V) characteristics, it was found that the devices exhibit outstanding switching diode and tunneling diode behavior at room temperature, which seems to be due to the asymmetric device structure. These electrical properties of the devices may be applicable to active components for the memory and/or logic circuits in the future.

We have seen the effects of buffer layer in organic light-emitting diodes using poly(vinylcarbazole) (PVK) and copper phthalocyanine (CuPc) in a device structure of ITO/buffer/TPD/Alq3/Al. Polymer PVK buffer layer was made using spin casting method and CuPc layer was made using thermal evaporation. Current–voltage characteristics, luminance–voltage characteristics and external quantum efficiency were measured at room temperature with a thickness variation of PVK and CuPc layer. We have obtained an improvement of the external quantum efficiency by a factor of four when the PVK buffer layer is used. And we have also obtained an improvement of efficiency by a factor of two when the CuPc buffer layer is used. Our analysis shows that the PVK and CuPc layer are good candidates for hole-injection buffer layer. A reason for the improvement of the efficiency is that the PVK layer functions as a hole blocking and the CuPc layer as a hole injection supporter.

We have synthesized green light-emitting material, poly(3,6-N−2-ethylhexyl carbazolyl cyanotere-phthalidene)(PECCP), which has an electron-donor and electron-acceptor moiety in a repeated unit of polymer. Organic light-emitting diodes were made with PECCP Langmuir-Blodgett(LB) films in a sandwich structure between indium-tin-oxide(ITO) and aluminum electrodes. Z-type LB films were manufactured using a Kuhn type to use for an emissive layer. We have observed green photoluminescent and electroluminescent spectra at λmax = 536 nm corresponding to 2.31 eV.

We observed EL properties based on PVK, poly(3,6-N-2-ethylhexyl carbazolyl cyanoterephthalidene) (PECCP) and Alq3 emitting material devices with doped PPy conducting layer (>5 S/cm) and undoped polyacetylene derivative layer (PEPB, 10−10–10−11 S/cm) on top of rough ITO (surface resistance: less than 7 Ω/□). PPy conducting layer improved an EL efficiency of ITO/TPD/Alq3/Al device, which has a rough ITO surface of more than 1000 A peak to peak level. In PVK, PECCP EML device, when PPy is layered on top of ITO, the turn-on voltage is lowered from 13 to 10 V and from 15 to 9 V, respectively. The conductivity of undoped PEPB film is too low to improve EL property though it has good smoothness.

A new blue electroluminescent material analog to poly(3,6-N-2-ethylhexylcarbazolyl cyanotere-phthalidene) (PECCP) was synthesized by a facile reaction of 9-ethyl–3-carbazole carboxy aldehyde with 1,4-phenylenediacetonitrile. The resulting bis(3-N-ethylcarbazolyl)cyanoterephthalidene (BECCP) having cyano (electron acceptor part) and carbazole moiety (electron donor part) was characterized by NMR, IR, UV and was vacuum-deposited into thin film of smooth surface. BECCP shows blue PL and EL spectra at 480 nm corresponding to 2.58 eV and typical rectifying diode characteristics in ITO/BECCP/Al devices in both forward and reverse bias. The turn on voltage are +8 V and 4 V when the BECCP layer are 600 and 300 A thick, respectively.

Organic electroluminescent devices were fabricated using Alq3 (8-hydroxyquinolinate aluminum) and TPD (N,N′-diphenyl-N,N′-bis (3-methylphenyl)-[1-1′-biphenyl]-4,4′-diamine). We investigated current-voltage characteristics of the EL devices having buffer layer of PEI (Poly ether imide) blended with TPD, and conducting polymer PEDT (3,4-pyrazino-3′,4′-ethylenedithio-2,2′,5,5′-tetrathiafulvalenium). We measured UV/visible absorption spectrum. and PL (Photoluminescence) spectrum.

Electrical properties of C22-quinolinium(TCNQ) and polyamic acid alkylamine salts Langmuir–Blodgett (LB) films have been investigated through a study of surface pressure (π)–area (A) isotherms, current–voltage(I–V) characteristics, frequency-dependent dielectric responses, and thermally-stimulated currents (TSC). Through-plane I–V characteristics of C22-quinolinium(TCNQ) LB films show an anomalous behavior of breakdown near the electric-field strength of 106 V/cm. Frequency-dependent dielectric constants of the thermally annealed C22-quinolinium(TCNQ) LB films show that there are two characteristic dispersions in a frequency range of 10–13 Hz; one is a dispersion occurring near 1 MHz coming from the orientational polarization of the molecules and the other is probably due to an interfacial polarization below 1 kHz when the annealing temperature is above 80°C. The annealing temperature-dependent dielectric constants of the C22-quinolinium(TCNQ) LB films show that there are two maximum; one at near 80°C and the other at near 180°C. The first peak seems to be related to a disorder of alkyl chains. In the I–V characteristics of Z-type polyamic acid alkylamine salts (PAAS) LB films measured along the through-plane at room temperature, ohmic conduction has been observed below around 105 V/cm, which is similar to that of C22-quinolinium(TCNQ) LB films. Non-ohmic conduction has been observed above around 105 V/cm and the conduction mechanism can be explained by Schottky effect. Frequency-dependent dielectric responses of the PAAS LB film show that there is a dispersion at 104 Hz when the annealing temperature reaches about 100°C. Measurements of thermally-stimulated currents of those LB films were performed from room temperature to about 250°C and the temperature was increased at a rate of 0.2°C/s linearly. TSC peaks are observed at about 70°C in the arachidic acid LB films, and at about 70 and 160°C in the PAAS LB films. They indicate that the peak at 70°C is resulted from the alkyl group, and the other peak at 160°C is probably due to C O group in PAAS molecules.

This paper describes thermally stimulated currents (TSCs) of arachidic acid (AA) and polyamic acid alkylamine salts (PAAS) Langmuir–Blodgett (LB) films. The measurements were performed from room temperature to about 250°C and the temperature was increased at a rate of 0.2°C/s linearly. Two peaks are observed at about 70°C and 90°C in the arachidic acid LB films, and at about 70°C and 160°C in the PAAS LB films. They indicate that the peak at 70°C arises from the alkyl group, and the other peak at 160°C in PAAS LB film may be due to the C–O group. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) of the PAAS and arachidic acid powder were measured and analyzed.

Most Korean community represents the primary effluent of 180 mg/L COD, 80 mg/L BOD, 25 mg/L TKN and 4 mg/L TP. A/O, A2/O and MUCT (Modified University of Cape Town) systems were applied to laboratory scale reactor with a temperature of 10 to 20°C. A total of 6 hour hydraulic retention time including anaerobic, anoxic and aerobic zones was used with a maximum 3,000 mg/L MLSS to simulate the existing municipal plants. All BNR systems represented effluent BOD less than 10 mg/L. MUCT produced better quality; 0.5 mg/L SP (soluble phosphorus) with 10 mg/L TN vs 1.8 mg/L SP with 12 mg/L TN for A2/O with the same internal recycle ratio. Performance of BNR systems would suggest the primary effluent used for this study represents a nature of slowly biodegradable COD. As that result, anaerobic fraction must be increased to attain lower effluent P concentrations. However, prefermentation to increase Premoval was not necessary since P was also limited. Microbial mass fractions computed from COD and nitrogen mass balances suggested that poly-P microbes were about 33% in A/O and MUCT, denitrifier fractions were about 30% in A2/O and MUCT. Nitrifier fractions were about 2%.

This paper describes the thermally stimulated currents (TSCs) of acidic (AA) and polyamic acid alkylamine salts (PAAS) Langmuir-Blodgett (LB) films. The measurements were performed from room temperature to about 250/spl deg/C and the temperature was increased at a rate of 0.02/spl deg/C/s linearly. Peaks of TSCs are observed at about 80/spl deg/C in the arachidic acid LB films and at about 80/spl deg/C and 16/spl deg/C in the PAAS LB films. They indicate that the peak at 80/spl deg/C is resulted from alkyl group, and the other peak at 160/spl deg/C is due to alkyl and C-O group in PAAS molecules. The additional large peak at about 160/spl deg/C is due to dipole moments of the PAAS molecules. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) of the PAAS and arachidic acid molecules were measured and analyzed.

Temperature dependence of current-voltage-luminance characteristics in organic light-emitting diodes are studied in a device structure of ITO/TPD/Alq 3 /Al to understand an electrical conduction mechanism. The current-voltage-luminance characteristics are measured in the temperature range of 8K∼300K, and analyzed them using a hopping model with exponential trap distribution and Fowler-Nordheim tunneling. At low temperatures below 150K, the Fowler-Nordheim tunneling conduction mechanism is dominant. And we have obtained a zero field barrier height to be about 0.6∼0.8eV.

Green light-emitting material, poly(3,6-N-2-ethylhexyl carbazolyl cyanotere-phthalidene)(PECCP), was synthesized which has an electron-donor and electron-acceptor moiety in a repeated unit of polymer. We have made PECCP Langmuir-Blodgett(LB) films and they exhibit fluorescence. Organic light-emitting diodes with a single-layer structure (ITO/emitting layer/Al) have been fabricated with the PECCP LB films as an emitting material. We have observed green photoluminescent and electroluminescent spectra at λ max = 536nm corresponding to 2.34eV.