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排序方式: 共有135条查询结果,搜索用时 15 毫秒
1.
Book Reviewed: Iain E.G. Richardson, H.264 and MPEG-4 VideoCompression: Video Coding for Next-GenerationMultimedia, John Wiley & Sons, 2003, $102.00, 206 pp., ISBN 0-470-84837-5. 相似文献
2.
Jale F. Akyurtlu Ates Akyurtlu Charles E. Hamrin JR 《Chemical Engineering Communications》1988,66(1):169-187
A theoretical investigation of a catalytic porous-wall reactor in which gaseous and liquid reactants approach each other from opposite sides of the catalyst is undertaken. Equations for the annular liquid-channel are coupled with those for the catalytic wall and solved numerically and analytically using a simplified model. For the model reaction under study, the main design and operation parameters which affect reactor performance are the Thiele modulus, Peclet number, width of the liquid channel and the inlet concentration of the reactant in the liquid phase.
The effect of reactor configuration is peculiar to the cylindrical geometry because the thickness and relative location of the catalytic wall as well as the selection of the liquid and gas channels can influence the reactor performance. Thin-walled catalyst tubes have larger effectiveness factors and as the tube radius approaches that of the reactor, conversion in the reactor increases especially when the liquid is saturated with the gaseous reactant. Concentration of the liquid reactant in the feed has a significant effect if the reactant is depleted at some point inside the catalyst wall. Since the reaction zone width can be adjusted by changing the feed composition, this might have important implications with respect to selectivity. 相似文献
The effect of reactor configuration is peculiar to the cylindrical geometry because the thickness and relative location of the catalytic wall as well as the selection of the liquid and gas channels can influence the reactor performance. Thin-walled catalyst tubes have larger effectiveness factors and as the tube radius approaches that of the reactor, conversion in the reactor increases especially when the liquid is saturated with the gaseous reactant. Concentration of the liquid reactant in the feed has a significant effect if the reactant is depleted at some point inside the catalyst wall. Since the reaction zone width can be adjusted by changing the feed composition, this might have important implications with respect to selectivity. 相似文献
3.
Turbidity and chemical oxygen demand (COD) removal efficiencies were analyzed depending on electrode layouts by performing electrocoagulation experiments using horizontal and vertical electrochemical cells. Multiple aluminum plate electrodes were placed into different sections of the electrochemical cells. Removal efficiencies at the horizontal electrochemical cell were always higher than the one’s obtained from the vertical electrochemical cell. But the use of vertical electrochemical cell consumed less energy during the electrocoagulation tests. The highest COD removal efficiencies were 97% and 88% in the horizontal and vertical electrochemical cells, respectively. However, the energy consumption for COD removal in the horizontal electrochemical cell was 47% higher than the energy consumed in the vertical electrochemical cell. 相似文献
4.
5.
Gulsah Congur Elif Selen Ates Aysegul Afal Husnu Emrah Unalan Arzum Erdem 《Journal of the American Ceramic Society》2015,98(2):663-668
The surfaces of pencil graphite electrodes (PGEs) were decorated with zinc oxide nanowires (ZnO NWs) for the electrochemical detection of nucleic acids. ZnO NWs were synthesized through simple hydrothermal method. PGEs decorated with ZnO NWs (ZnO NW/PGEs) were electrochemically characterized through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) following morphological characterization through transmission (TEM) and scanning electron microscopy (SEM). Enhanced sensor response obtained using ZnO NW/PGEs contrary to the bare PGE (control) samples. Our preliminary results simply reveal the potential of combining ZnO NWs with disposable sensor technology for the electrochemical detection of DNA. 相似文献
6.
Polypyrrole/multi-walled carbon nanotube, poly(3,4-ethylenedioxythiophene)/multi-walled carbon nanotube and their nanocomposites P(EDOT-co-Py)/multi-walled carbon nanotube and P(EDOT-co-Py)/copper (II) oxide, (CuO) in the initial feed ratio of [EDOT]0/[Py]0 = 1/5 were electrosynthesized on glassy carbon electrode by cyclic voltammetric method. Their characterizations were performed by cyclic voltammetric, Fourier transform infrared-attenuated total reflectance, scanning electron microscopy, energy dispersion X-ray analysis, and electrochemical impedance spectroscopy. To the best of authors’ knowledge, the first report on polypyrrole/multi-walled carbon nanotube, PEDOT/multi-walled carbon nanotube, P(EDOT-co-Py)/multi-walled carbon nanotube and P(EDOT-co-Py)/CuO nanocomposite films were comparatively examined in 0.1 M NaClO4/CH3CN and in 0.1 M sodium dodecyl sulfate solutions. The highest specific capacitance for PEDOT/multi-walled carbon nanotube and polypyrrole/multi-walled carbon nanotube composite films were obtained as Csp = 306 mF × cm?2 for 3% multi-walled carbon nanotube and Csp = 804 mF × cm?2 for 1% multi-walled carbon nanotube, respectively. The highest specific capacitances were obtained as Csp = 27.40 mF × cm?2 and Csp = 26.90 mF × cm?2 for P(EDOT-co-Py)/multi-walled carbon nanotube includes the wt percent of 1% multi-walled carbon nanotube and P(EDOT-co-Py)/CuO includes the wt percent of 3% CuO, respectively. The Csp of P(EDOT-co-Py)/CNT composite films were calculated as 9.43 and 11.49 mF × cm?2 for 3 and 5% multi-walled carbon nanotube, respectively. In addition, The EIS results were simulated with the equivalent circuit model of Rs(Cdl1(R1(QR2)))(Cdl2R3). 相似文献
7.
Synthesis and characterization of PMMA composites activated with starch for immobilization of L‐asparaginase
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Poly (methyl methacrylate) (PMMA)–starch composites were prepared by emulsion polymerization technique for L‐asparaginase (L‐ASNase) immobilization as highly activated support. The hydroxide groups on the prepared composites offer a very simple, mild and firm combination for enzyme immobilization. The pure PMMA and PMMA‐starch composites were characterized as structural, thermal and morphological. PMMA‐starch composites were found to have better thermal stability and more hydrophilic character than pure PMMA. L‐ASNase was immobilized onto PMMA‐starch composites contained the different ratio of starch (1, 3, 5, and 10 wt %). Immobilized L‐ASNase showed better performance as compared to the native enzyme in terms of thermal stability and pH. Km value of immobilized enzyme decreased approximately eightfold compared with the native enzyme. In addition to, immobilized L‐ASNase was found to retain 60% of activity after 1‐month storage period at 4 °C. Therefore, PMMA‐starch composites can be provided more advantageous in terms of enzymatic affinity, thermal, pH and storage stability as L‐ASNase immobilization matrix. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43421. 相似文献
8.
Several building codes such as ANSI/AISC 360‐16 and EC3 EN 1993‐1‐1 require the use of a proper design method to consider instability and second‐order load effect problems for individual system elements and the entire structural system. Various methods are available to assess stability. All of these methods should consider P‐Δ and P‐δ effects (second‐order effects). The following calculation procedures are presented in this study: (a) a simplified method is developed for P‐Δ and P‐δ analysis in regular frames under the effect of constant axial loads to obtain story drifts and end moments; (b) this method can be applied to an entire building or any individual story, that is, story‐based design is possible; and (c) column effective length factors are obtained for individual columns. In addition, design tables are presented. 相似文献
9.
In this study, current and voltage transfer function filters using single active component, namely, current backward transconductance amplifier (CBTA) are presented. The proposed structures are a single-input three outputs (SITO) current-transfer function filter, a single-input four-output (SIFO) voltage transfer function filter and three-input single-output (TISO) voltage transfer function filter. The proposed filters have low active and passive sensitivities and use canonical number of electronics components. The validity of the proposed circuits is demonstrated by PSPICE simulations and experimental results. Operation range of the CBTA and its parasitic effects are also discussed. 相似文献
10.
Chander Shekhar Sharma Amanda Ates Poulson Joseph Kamlesh A. Soni M. Wes Schilling Aaron Kiess 《International Journal of Food Science & Technology》2013,48(7):1410-1415
The efficacy of lauric arginate (LAE) on Salmonella survivability in ground chicken containing 9.8% fat was determined under refrigerated storage. The effect of LAE treatments on total aerobes, pH and objective colour were also assessed in ground chicken. LAE was highly effective against Salmonella in 0.1% peptone with no detectable survivors following treatment with 200 ppm and 400 ppm of LAE. No difference existed (P > 0.05) in the growth of Salmonella and total aerobes after treatment with 200 and 400 ppm of LAE in ground chicken inoculated with a four strain mixture of Salmonella. At these concentrations, LAE did not exhibit any treatment effect on the pH and colour of ground chicken (P > 0.05). In conclusion, although LAE possesses strong inhibitory (P < 0.05) effect against Salmonella in suspension in 0.1% peptone water, no inhibitory (P > 0.05) effect on growth of Salmonella was observed in ground chicken at the currently approved levels of 200 ppm of LAE. 相似文献