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11.
Fullerene(C60)‐dibenzo‐16‐crown‐5‐oxyacetic acid (DBI6C5‐OCH2‐COOC60) was prepared and applied as the coating material on piezoelectric quartz crystals for detection of various metal ions and polar/nonpolar organic molecules. The C60‐crown ether‐coated piezoelectric crystal sensor with a home‐made computer interface for signal acquisition and data processing was applied as an ion chromatographic (IC) detector for various metal ions, e.g., alkali metal, alkaline earth metal and transition‐metal ions. The piezoelectric detector exhibited quite good sensitivity of 104 ~ 106 Hz/M and good detection limit of 10?3 ~ 10?4 M for these metal ions. The C60‐crown ether piezoelectric detector compared well with the commercial conductivity detector conventionally used for metal ions. The ionic size and ionic charge seemed to have significant effect on the frequency response of the piezoelectric detector. The C60‐crown ether coated piezoelectric crystal sensor was also employed as a high performance liquid chromatographic (HPLC) detector for various polar organic molecules with frequency responses in the order: amines > carboxylic acids > alcohols > ketones. Furthermore, nonpolar organic molecules, e.g., n‐hexane, 1‐hexene and 1‐hexyne, were also detected with this piezoelectric crystal detector. The frequency responses of the piezoelectric crystal detector for these nonpolar organic molecules were in the following order: alkynes > alkenes > alkanes. The effects of solvents and flow rate on the frequency responses of the piezoelectric crystal detector were investigated. The C60‐crown ether coated piezoelectric crystal detector also showed short response time (< 1 min.) and good reproducibility. 相似文献
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Hong Chi Siew Lay Lim Fuke Wang Xizu Wang Chaobin He Wee Shong Chin 《Macromolecular rapid communications》2014,35(8):801-806
Emission of conjugated polymers is known to undergo bathochromic shift from solution to film formation due to π–π stacking in the solid state. In this report, a series of pearl‐necklace‐like hybrid polymers is designed via the hydrosilylation condensation between bifunctional polyhedral oligomeric silsesquioxanes ( B‐POSS ) and oligofluorene segments. Optoelectronic analyses unequivocally show that the presence of these interconnecting B‐POSS can effectively reduce red‐shift in photoluminescence and electroluminescence during film formation. These hybrid poly(oligofluorenes) display stable blue emission with high color purity. Thermal analyses also indicate that they are vitrified polymers with high glass transition temperature (up to 125 °C). We believe that this strategy can be extended to other conjugated systems to control color purity in electroactive materials and holds promise as new emissive materials for various applications.
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Bi‐channel Surface Acoustic Wave Gas Sensor for Carbon Disulfide and Methanol Vapors in Polymer Plants 下载免费PDF全文
A C60‐polyphenylacetylene (C60‐PPA) and polyvinylpyrrolidone (PVP) coated two‐channel surface acoustic wave (SAW) crystal gas sensor with a homemade computer interface for data acquisition and data processing was developed and employed to detect carbon disulfide (CS2) and methanol (CH3OH) vapors in polymer plants. The frequency of surface acoustic wave oscillator decreases due to the adsorption of gas molecules on the coated materials of the SAW sensor. Six coating materials (C60‐PPA, nafion, PPA, crytand [2,2], polyethene glycol and PVP) were used to adsorb and detect carbon disulfide and methanol gases. Adsorption of all the six coating materials to CS2 and CH3OH was found to be physical adsorption. The C60‐PPA coated SAW detector exhibited more sensitive to CS2 than the other coating materials. In contrast, the PVP coated SAW detector was more sensitive to CH3OH than the other coating materials. With the two‐channel SAW sensor, the C60‐PPA coated SAW showed a good detection limit of 0.4 ppm and good reproducibility with RSD of 3.37 % (n=10) for CS2. Similarly, the PVP coated SAW also showed a good detection limit of 0.05 ppm and good reproducibility, with RSD of 0.86 % (n=10) for CH3OH. The interference effect of other organic molecules on the SAW detection system was negligible, except for the irreversible adsorption of C60‐PPA to propylamine. The frequency signals from the two‐channel SAW sensor array C60‐PPA and PVP coatings were processed by a back‐propagation artificial neural network (BPN) and multiple regression analysis (MRA). Thus a two‐channel SAW sensor array with BPN and MRA has been successfully applied for the qualitative and quantitative analyses of CS2 and CH3OH in mixtures. 相似文献
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本文考虑一般的半线性抛物型方程ut=uxx+f(u,ux,t)的爆破点集,证明在一定条件下,爆破只能在一点发生 相似文献
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超强激光的等离子体烧孔效应 总被引:1,自引:1,他引:0
针对激光聚变快速点火方案中的等离子体烧孔效应,用活塞模型研究了超强激光压缩等离子体并直接驱动激波的过程,给出了描述该过程的各物理参量的理论定标律。 相似文献
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