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141.
Jang Myoun Ko Kwang Sun Ryu Sanghyo Kim Kwang Man Kim 《Journal of Applied Electrochemistry》2009,39(8):1331-1337
Three types of composite supercapacitor electrodes were prepared; electroactive polyaniline (PANI), PANI/multi-walled carbon
nanotube (CNT), and PANI/CNT/RuO2. Specifically, the PANI and PANI/CNT were prepared by polymerization, and PANI/CNT/RuO2 was prepared by electrochemical deposition of RuO2 on the PANI/CNT matrix. Cyclic voltammetry between −0.2 and 0.8 V (vs. Ag/AgCl) at various scan rates was performed to investigate
the supercapacitive properties in an electrolyte solution of 1.0 M H2SO4. The PANI/CNT/RuO2 electrode showed the highest specific capacitance at all scan rates (e.g., 441 and 392 F g−1 at 100 and 1,000 mV s−1, respectively). In contrast, the PANI/CNT electrode demonstrated the best capacitance retention (66%) after 104 cycles. Additional analysis including morphology and complex impedance spectroscopy suggested that with small loading of
RuO2, an increase in capacitance was observed, but dissolution and/or detachment of RuO2 species from the electrode might occur during cycling to reduce the cycle performance. 相似文献
142.
Rajkumar Patel Se Jun Im Yun Taek Ko Jong Hak Kim Byoung Ryul Min 《Journal of Industrial and Engineering Chemistry》2009,15(3):299-303
The syntheses of series of proton conducting comb copolymer membrane involving polysulfone back bone as main chain and poly(styrene sulfonic acid) (PSSA) being side chain, i.e. polysulfone grafted poly(styrene sulfonic acid) (PSU-g-PSSA) are presented. Chloromethylation of the polysulfone backbone was done by Fridel Craft alkylation reaction. Atom transfer radical polymerization was used for control grafting from the chloromethylated positions. The successful substitution of the chloromethyl group and its grafting with PSSA was characterized by elemental analysis and proton nuclear magnetic resonance. Water uptake, electrochemical properties like ion exchange capacity (IEC) and proton conductivities increase with increase in PSSA contents. Thermal gravimetric analysis (TGA) showed the thermal stability of membranes up to 250 °C. Proton conductivity for maximum amount of grafting is 0.02 S/cm. 相似文献
143.
This study was performed to develop a Real-Time Risk Monitoring System which helps to do fault detection using the information
from plant information systems in a chemical process. In this study, to do fault detection, principal component analysis (PCA)
methods of multivariate statistical analysis were used. The fundamental notions are a set of variable combinations, that is,
detection of principal components which indicate the tendency of variables and operating data. Besides classical statistic
process control, PCA can reduce the dimension of variables with monitoring process. Therefore, they are known as suitable
methods to treat enormous data composed of many dimensions. The developed Real-Time Risk Monitoring System can analyze and
manage the plant information on-line, diagnose causes of abnormality and so prevent major accidents. It’s useful for operators
to treat numerous process faults efficiently. 相似文献
144.
Joo Young Lee Joong Won Lee Jaewook Ko En Sup Yoon 《Korean Journal of Chemical Engineering》2005,22(5):649-656
Accidents caused by the domino effect in chemical plants or the petrochemical industry are generally more serious than any
other accident. But it is difficult to examine the true factor because the domino effect is influenced by many nonlinear factors.
The immediate causes of the domino effect are the peak overpressure, flying objects, and flame. Nonlinearity is inherent in
all three causes. However, it is believed that a systematic and mathematical approach can minimize the incidence of the domino
effect. We considered the case where there were n-explosive facilities in a given arbitrary rectangular facility site. This
paper suggests the positions that can minimize the domino effect using a nonlinear approach. The method initiated an arbitrary
number of facilities in addition to the original position, and can search for the position to minimize the domino effect.
This paper presents a new computer-aided module, MiniFFECT (MINImization of domino eFFECT). 相似文献
145.
Per Johan Råsmark Čestmír Koňák Petr Štěpánek Christer Elvingson 《Polymer Bulletin》2005,54(4-5):335-342
Summary Dynamic light scattering was used to investigate the dynamics of sodium poly(styrene sulfonate) and fully neutralized poly(acrylic acid) gels as a function of the degree of swelling and weight ratio of cross-linking agent. It was shown that the collective diffusion coefficient increases with increasing degree of swelling and that the diffusion coefficient shows stronger concentration dependence than predicted by scaling arguments. For gel samples measured at the swelling equilibrium, the diffusion coefficient increases with increasing gel concentration for both gel systems. 相似文献
146.
In this work the method of response surfaces was used for the purpose of drawing up a mathematical model for the calculation (forecasting) of the adhesion of a flame sprayed coating of powdered aluminum on S 235 JR steel. Experimental work was conducted according to a fractional central-composite design at three levels. The adhesion of the coatings made with combinations of input parameters of the procedure according to the experiment plan mentioned is measured in line with the EN 582 standard. A mathematical model was derived describing the dependence of the experimentally obtained adhesion values on the input parameters of the procedure. The possibility of analyzing the influence of the parameters on the adhesion for a certain combination of input parameters has been presented with the use of perturbation plots. 相似文献
147.
Sónia Simões Filomena Viana Mustafa Koçak A. Sofia Ramos M. Teresa Vieira Manuel F. Vieira 《Journal of Materials Engineering and Performance》2012,21(5):678-682
In this article, the characterization of the interfacial structure of diffusion bonding a TiAl alloy is presented. The joining surfaces were modified by Ni/Al reactive multilayer deposition as an alternative approach to conventional diffusion bonding. TiAl substrates were coated with alternated Ni and Al nanolayers. The nanolayers were deposited by dc magnetron sputtering with 14 nm of period (bilayer thickness). Joining experiments were performed at 900 °C for 30 and 60 min with a pressure of 5 MPa. Cross sections of the joints were prepared for characterization of their interfaces by scanning electron microscopy (SEM), transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), high resolution TEM (HRTEM), energy dispersive x-ray spectroscopy (EDS), and electron backscatter diffraction (EBSD). Several intermetallic compounds form at the interface, assuring the bonding of the TiAl. The interface can be divided into three distinct zones: zone 1 exhibits elongated nanograins, very small equiaxed grains are observed in zone 2, while zone 3 has larger equiaxed grains. EBSD analysis reveals that zone 1 corresponds to the intermetallic Al2NiTi and AlNiTi, and zones 2 and 3 to NiAl. 相似文献
148.
H. Y. Koo J. H. Kim S. K. Hong Y. N. Ko H. C. Jang D. S. Jung J. M. Han Y. J. Hong Y. C. Kang S. H. Kang S. B. Cho 《Metals and Materials International》2012,18(3):445-449
Fe powders as the heat pellet material for thermal batteries are prepared from iron oxide powders obtained by spray pyrolysis from a spray solution of iron nitrate with ethylene glycol. The iron oxide powders with hollow and thin wall structure produce Fe powders with elongated structure and fine primary particle size at a low reducing temperature of 615 °C. The mean size of the primary Fe powders with elongated structure decreases with increasing concentration of ethylene glycol dissolved into the spray solution. The heat pellets prepared from the fine-size Fe powders with elongated structure have good ignition sensitivities below 1 watt. The heat pellets formed from the Fe powders obtained from the spray solution with 0.5 M EG have an extremely high burn rate of 26 cms?1. 相似文献
149.
Correlation between current frequency and electrochemical properties of Mg alloy coated by micro arc oxidation 总被引:2,自引:0,他引:2
The present work investigated the electrochemical behavior of Mg alloy subjected to micro arc oxidation coating for 120 s with respect to current frequencies from 60 Hz to 2000 Hz. The microstructure and chemical compound of thin coating layers with a thickness of ~ 3 μm were analyzed using scanning electron microscopy and X-ray photoelectron spectroscopy. The microstructural observations on the surface and cross sections revealed that both the size of pores and the number of discharge channels decreased significantly as the current frequency increased, resulting in a compact coating layer. This was primarily attributed to the transition time of the alternating electrical wave, which was determined by the current frequencies tested. Based on potentiodynamic polarization tests, the sample coated at a frequency of 2000 Hz demonstrated the highest polarization resistance of 6.37 × 105 Ω cm2, implying that the corrosion resistance was superior to that obtained under other conditions due to its condensed structure. This electrochemical response was also interpreted in relation to the equivalent circuit model. 相似文献
150.
In this study, 1-(2,6-diisopropylphenyl)-2,5-di(2-thienyl)pyrrole-based metal-free organic dyes containing three different non planar electron donor groups such as methoxy or hexyloxy substituted triphenylamine and difluorenephenylamine were prepared in order to see the effect of electron donor groups on the opto-electrical properties and applied in dye-sensitized solar cells (DSSC). All three dyes showed broad absorption band in visible part of the solar spectrum (∼300 nm–600 nm). The dye (TPTDYE-3) containing sterically less hindered methoxy substituted triphenylamine was found to show relatively red shifted absorption compared to that of the dye (TPTDYE-4) containing hexyloxy substituted triphenylamine or the dye (TPTDYE-5) containing difluorenephenylamine. The optical band gaps of the three dyes were calculated to be 2.19 eV, 2.22 eV and 2.24 eV, respectively, and the highest occupied molecular orbital (HOMO) energy levels of the three dyes were found to be located at 0.65 V, 0.68 V and 0.75 V, respectively. The DSSC performance of each dye was investigated with and without coadsorbent. The maximum solar to electrical energy conversion efficiencies (η) of the DSSCs made from only sensitizer were 4.18%, 5.28% and 5.42% while those of the DSSCs made from sensitizer with coadsorbent were 5.47%, 5.58% and 5.63%, respectively. 相似文献