排序方式: 共有71条查询结果,搜索用时 15 毫秒
41.
Demet Kuruo?lu Esin Canel Shahabuddin Memon Mustafa Yilmaz Esma Kili? 《Analytical sciences》2003,19(2):217-221
A hydrogen ion-selective poly(vinyl chloride) membrane electrode was constructed using 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetracyanomethoxycalix[4]arene as a neutral carrier. The electrode showed an apparent Nernstian response in the 2-11.5 pH range with a slope of 54.0 +/- 0.2 mV/pH at 20 +/- degrees C. This electrode showed a rapid response of the emf to changes in the pH, high ion selectivity with respect to lithium, sodium and potassium, and characteristics similar to those reported for the conventional pH glass membrane electrode. It can be used as a potentiometric indicator electrode in hydrofluoric acid solutions. The effects of iodide, thiocyanate, perchlorate and bromide on the characteristics of the electrode were also considered. 相似文献
42.
We classify all helicoidal non-degenerate surfaces in Minkowski space with constant mean curvature whose generating curve is a the graph of a polynomial or a Lorentzian circle. In the first case, we prove that the degree of the polynomial is 0 or 1 and that the surface is ruled. If the generating curve is a Lorentzian circle, we prove that the only possibility is that the axis is spacelike and the center of the circle lies on the axis. 相似文献
43.
Purification and characterization of organic solvent stable serine alkaline protease from newly isolated Bacillus circulans M34
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A protease from newly isolated Bacillus circulans M34 was purified by Q‐Sepharose anion exchange chromatography and Sepharose–bacitracin affinity chromatography followed by (NH4)2SO4 precipitation. The molecular mass of the purified enzyme was determined using SDS–PAGE. The optimum pH and temperature for protease activity were 11 and 50°C, respectively. The effect of various metal ions on protease activity was investigated. Alkaline protease from Bacillus circulans M34 wase activated by Zn2+, Cu2+ and Co2+ up to 31%. The purified protease was found to be stable in the organic solvents, surfactants and oxidizing agent. The substrate specificity of purified protease was investigated towards different substrates. The protease was almost completely inhibited by the serine protease inhibitor phenylmethanesulfonyl fluoride. The kinetic parameters of the purified protease, maximum rate (Vmax) and Michaelis constant (Km), were determined using a Lineweaver–Burk plot. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
44.
This study focuses on exact solutions of nonlinear Schrödinger equation in a power law media with fourth order dispersion. Jacobi elliptic functions will be used to carry out the integration of this equation. Bright, dark and singular optical soliton solutions are obtained as well as Jacobi elliptic function solutions. 相似文献
45.
Journal of Nanoparticle Research - In recent years, nickel nanoparticles (Ni NPs) have attracted a growing attention from the scientific research community, because they are inexpensive,... 相似文献
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Hassan Ridaoui Ali Dirani Olivier Soppera Esma Ismailova Cyril Brochon Guy Schlatter Georges Hadziioannou Raluca Tiron Philippe Bandelier Claire Sourd 《Journal of polymer science. Part A, Polymer chemistry》2010,48(6):1271-1277
Next generations of microelectronic devices request further miniaturized systems. In this context, photolithography is a key step and many efforts have been paid to develop new irradiation setup and materials compatible with sub‐100 nm resolution. Among other resist platforms, chemically amplified photoresists (CAR) are widely used because of their excellent properties in terms of resolution, sensitivity, and etching resistance. However, low information on the impact of the polymer structure on the lithography performance is available. CAR with well‐controlled polymer structures were thus prepared and investigated. In particular, the impact of the polymer structure on the lithographic performance was evaluated. Linear and branched polymers with various molecular weights and polydispersities were compared. We focused on the dependency of the photosensitivity of the resist with the structural parameters. These results allow further understanding the fundamental phenomena involved by 193‐nm irradiation. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1271–1277, 2010 相似文献
48.
The dynamics and throughput of a bucket brigade production system is studied when workers’ speeds increase due to learning. It is shown that, if the rules of the bucket brigade system allow a re-ordering of its workers then the bucket brigade production system is very robust and will typically rebalance to a self-organizing optimal production arrangement. As workers learn only those parts of the production line that they work on, the stationary velocity distribution for the workers of a stable bucket brigade is non-uniform over the production line. Hence, depending on the initial placement of the workers, there are many different stationary velocity distributions. It is shown that all the stationary distributions lead to the same throughput. 相似文献
49.
Choukchou-Braham Esma Benabadji Kamel Ismet Benkhaled Amel Sekkal Amina Rim Heddi Djawhar Djamaà Zoulikha 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(4):273-279
The removal of orange Telon from aqueous solutions by poly(N-octyl-4-vinylpyridiniumbromide) copolymer was investigated. Batch adsorption experiments were carried out to study the effect of experimental parameters on the orange Telon adsorption equilibrium. The adsorption characteristics of copolymer to ward orange Telon in dilute aqueous solution were followed using UV-Vis spectrophotometry. Adsorption equilibrium was reached within 60 min for 0.03 g of poly(4-vinylpyridine quaternized at 58%. The kinetic of adsorption is best described by a pseudo-second-order model. Results also showed that the equilibrium modeling of orange Telon removal process was described by Langmuir isotherms. The maximum adsorption capacity determined from the Langmuir isotherm was 76.4 mg g? 1. The study of the thermodynamic parameters showed that the adsorption of orange Telon on copolymer is an exothermic process and the randomness decreases at the solid-solution interface during the adsorption of dye on the copolymer. 相似文献
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Esma Dervisevic Muamer Dervisevic Yan Wang Luis F. Malaver‐Ortega Wenlong Cheng Kellie L. Tuck Nicolas H. Voelcker Victor J. Cadarso 《Electroanalysis》2020,32(8):1850-1858
The number of studies conducted about nonenzymatic electrochemical sensors has increased in recent years due to the development of more stable and robust electrodes using noble metals. One of the key aspects for achieving high sensing performance including detection limit and sensitivity is the design of electrode architecture. Herein, we report a new electrochemical sensing platform featuring ultrathin standing gold nanowires (AuNWs) for nonenzymatic detection of hydrogen peroxide (H2O2). The use of AuNWs resulted in an increased electron transfer efficiency due to the higher active surface area compared to traditional gold film electrodes. This sensor demonstrates good selectivity, reproducibility, a linear range up to 49.5 mM of H2O2 with a sensitivity of 0.185±0.003 mAmM?1cm?2 and a limit of detection of 111 μM. The biological relevance of this sensor was tested in cell culture media to illustrate the performance of the proposed sensing electrode in complex biological media. 相似文献