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171.
Wet molybdate sulfuric acid (= dioxo[bis(sulfato‐κO)]molybdenum; MSA), a new solid acid, can be used in combination with sodium nitrite (NaNO2) to transform a variety of secondary amines to the corresponding N‐nitroso compounds under mild, heterogeneous conditions (Table). The process has several advantages: the reagents are inexpensive and non‐hazardous, the reaction is clean, fast, and high‐yielding, and MSA can be readily removed by filtration and re‐used (after treatment with HCl) without loss of activity. Further, only N‐nitrosation was observed, but no C‐ or O‐nitrosation. 相似文献
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Dispersion characteristic of MI and MII type single mode optical fibers is analytically investigated. For this purpose modal analysis of these fibers to obtain possible wave vectors for given system parameters are done. Then using numerical evaluation of the presented analytical relations, chromatic and waveguide dispersions are calculated. The effects of geometrical and optical parameters of the fibers on dispersion characteristics are investigated. In this analysis, we show that with increase of Δ (optical parameter) for MI structure the slope of dispersion curve is decreased and the case is reversed for MII structure. Also, with rising of Q (geometric parameter) for MI structure the slope of dispersion curve is decreased and the situation is reversed for MII structure. Finally, we show that with boosting of R2 for MII structure the slope of dispersion is increased. As a final result, our simulations show that small values for optical parameters are better in MII structure for multi-channel optical communications. In MI structure to obtain small dispersion slope, Q can be increased that is easy for fabrication in practice. Finally, Q and R2 are suitable parameters for control of dispersion in the proposed structures. 相似文献
175.
Experimental study of the behavior of a valveless impedance pump 总被引:1,自引:0,他引:1
When a fluid-filled flexible tube is connected to tubing of different impedance, a net flow in either direction can be induced by periodically pinching the flexible section asymmetrically from the ends. We have experimentally demonstrated a variety of conditions under which pumping occurs; including changes in actuator position, size and pinching frequency, transmural pressure, systemic resistance and materials. Data collected includes dynamic pressure and flow-rate measurements at the inlet and outlet of the pump and ultrasound imaging of the tube walls. The net flow rate is highly sensitive to pinching frequency. The pump does not require a closed loop and can sustain a pressure head. We have also shown that a flexible, yet inelastic material is a sufficient condition for impedance-driven flow. A micro-scaled version of the pump was simultaneously tested demonstrating the feasibility of a miniature design.
An erratum to this article is avaliable at .
相似文献
An erratum to this article is avaliable at .
Anna Iwaniec HickersonEmail: Phone: +1-626-395-4758Fax: +1-626-577-5258 |
176.
Simultaneous determination of promethazine,chlorpromazine, and perphenazine by multivariate calibration methods and derivative spectrophotometry 总被引:1,自引:0,他引:1
Partial least-squares (PLS) regression, singular value decomposition-based PLS, and an artificial neural network (ANN) were tested as calibration procedures for the simultaneous determination of promethazine, chlorpromazine, and perphenazine by both conventional and derivative spectrophotometry. Comparison of the results revealed that the application of the ANN to the derivative spectra is superior to the application of the 2 PLS methods used. Different binary and ternary synthetic mixtures of the phenothiazine drugs in pure form and in tablets were analyzed by the proposed method, and acceptable results were obtained. 相似文献
177.
Morteza Ziaee Mostafa Yourdkhani 《Journal of polymer science. Part A, Polymer chemistry》2021,59(15):1732-1739
In thermal frontal polymerization (FP), ambient temperature and staging conditions highly affect the resin behavior and front properties. This study describes the effect of staging conditions and resin reactivity on frontal ring opening metathesis polymerization of dicyclopentadiene in presence of phosphite-inhibited second-generation Grubbs catalyst. An experimental setup is designed to characterize and understand the effect of inhibitor concentration, incubation time, and incubation temperature on front velocity, activation time, and front temperature of the FP reaction. The results reveal that front properties are influenced by various factors, including available energy density of resin, stability of catalyst-inhibitor complex, resin temperature, and resin viscosity. An increase in staging temperature results in lower pot lives but faster gelation process and activation of FP reaction. Additionally, increasing the inhibitor concentration leads to slower fronts, higher activation times, and longer pot lives. The results of this study can be extended to other FP systems and can be used in design of new manufacturing processes and applications using FP. 相似文献
178.
Ali Jebali Seyedhossein Hekmatimoghaddam Aliasghar Behzadi Iraj Rezapor Bahador Haji Mohammadi Tahereh Jasemizad Seyed Ali Yasini Morteza Javadzadeh Asiye Amiri Mansoure Soltani Zeynab Rezaei Najme Sedighi Mina Seyfi Mohammad Rezaei Mehran Sayadi 《Cellulose (London, England)》2013,20(6):2897-2907
In this study, cellulose nanoparticles were prepared by acid hydrolysis, separately conjugated with allicin and lysozyme by a carbodiimide cross-linker, and characterized by scanning electron microscopy, dynamic light scattering, and Fourier transform infrared spectroscopy. Then, their antimicrobial properties were evaluated by the microdilution method and compared with allicin, lysozyme, and nanocellulose alone. The results showed that nanocellulose had few antimicrobial activities, but allicin-conjugated nanocellulose (ACNC) and lysozyme-conjugated nanocellulose (LCNC) had good antifungal and antibacterial effects against standard strains of Candida albicans, Aspergillus niger, Staphylococcus aureus, and Escherichia coli. Noticeably, although allicin and lysozyme had different minimum inhibitory concentrations (MICs) against all strains, the same quantity of MIC50 and MIC90 was observed for both ACNC and LCNC. The authors suggest that both ACNC and LCNC can be used in industries as an antimicrobial agent in food packaging, inside foodstuffs, and in textile materials. 相似文献
179.
Preparation of Iodide Selective Carbon Paste Electrode with Modified Carbon Nanotubes by Potentiometric Method and Effect of CuS‐NPs on Its Response
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Mehrorang Ghaedi Seyedeh Yasaman Shajaripour Jaberi Shaaker Hajati Morteza Montazerozohori Masoumeh Zarr Arash Asfaram Lokesh Kumar Kumawat Vinod Kumar Gupta 《Electroanalysis》2015,27(6):1516-1522
In this research, multiwalled carbon nanotubes (MWCNTs) was oxidized and chemically modified through reaction with 3‐(trimethoxysilyl)propan‐1‐amine (TMSPA) and their subsequent reaction with 2‐hydroxy‐3‐methoxy benzaldehyde. Subsequently, this material was metalized by reaction with copper acetate that lead to formation and impergeation of 2‐methoxy‐6‐((3‐(trimethoxysilyl)propylimino)methyl)phenol MMSPIMP? MWCNT‐Cu. This novel material was identified with different techniques such as SEM and FT‐IR analysis. In this work, the reported material are exhibited high accurate and repeatable monitoring of iodide due to its high surface area with various reactive centre. It exhibited selectivity for iodide over the wide linear dynamic range between 1.8×10?6 and 1.15×10?1 M, with a Nernstian slope of ?59.12±0.7 mV per decade of activity and detection limit of 1.8×10?6 M. Copper sulfide nanoparticles were prepared and their effect on the electrode response was investigated. The results were improved in the presence of nanoparticles with fast and stable response, good reproducibility, long‐term stability, high selectivity over the presence of common organic and inorganic anions, high detection limit and dynamic range. The proposed sensor has been applied as potentiometric determination of some iodine species over a pH range of 2.5–10. 相似文献
180.