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61.
Conventional fabrication method of porous silicon is anodisation of single crystal silicon in hydrofluoric acid. In this report, we show that it is possible to fabricate porous silicon by laser-induced etching. An earlier report by us has demonstrated the dependence of porous silicon photoluminescence characteristic on the etching laser wavelength [1]. Here we used 780 nm line from a diode laser as the etching source, and the optimum etching conditions were obtained. A simple model was proposed to explain the etching process. Scanning Electron Microscope (SEM) images of the samples support the proposed process. 相似文献
62.
C. L. Choy W. P. Leung E. L. Ong Yimin Wang 《Journal of Polymer Science.Polymer Physics》1988,26(8):1569-1584
The nine independent stiffness constants Cpq for rolled nylon 66 at thickness reduction ratios λt = 2.4, 4.9, 7.6 have been measured from ?40 to 50°C by an ultrasonic method at 10 MHz. Analysis of x-ray pole figures indicates that at high λt the material has a uniplanar-axial texture, with hydrogen-bonded (010) planes parallel to the roll plane and the molecular chains along the roll direction. The mechanical behavior is determined not only by the alignment of molecular chains and hydrogen bonds but also by the microfibrillar morphology. On the basis of this idea the magnitudes of the tensile moduli along the three principal axes can be understood in terms of the Takayanagi model. The effects of water absorption have also been investigated. 相似文献
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65.
Shin Y Choy N Turner TR Balachandran R Madiraju C Day BW Curran DP 《Organic letters》2002,4(25):4443-4446
[structure: see text] Two hybrid analogues of discodermolide and dictyostatin (3, 26) have been designed and synthesized. These are the first macrocyclic analogues of discodermolide and biological activities were evaluated and compared with linear discodermolide analogues. 相似文献
66.
The kinetics of precipitation reactions with110AgNO3 of some di (β-chlorethyl) amine derivates and hydrochlorides with esters of N-(p-aminobenzoyl)-L-aspartic acid as carriers in dimethylformamide-water mixture, were studied. The rate constants of these reactions were of the order of 10?4 1 · mol?1 · min?1. The concentrations of the corresponding hydrochloride solutions were measured by radiometric titration with110AgNO3 solution of given concentration. 相似文献
67.
68.
Stowers MA van Wuijckhuijse AL Marijnissen JC Scarlett B van Baar BL Kientz CE 《Rapid communications in mass spectrometry : RCM》2000,14(10):829-833
Matrix-assisted laser desorption/ionization (MALDI) mass spectra were obtained from single biological aerosol particles using an aerosol time-of-flight mass spectrometer (ATOFMS). The inlet to the ATOFMS was coupled with an evaporation/condensation flow cell that allowed the aerosol to be coated with matrix material as the sampled stream entered the spectrometer. Mass spectra were generated from aerosol composed either of gramicidin-S or erythromycin, two small biological molecules, or from aerosolised spores of Bacillus subtilis var niger. Three different matrices were used: 3-nitrobenzyl alcohol, picolinic acid and sinapinic acid. A spectrum of gramicidin-S was generated from approximately 250 attomoles of material using a molar ratio of 3-nitrobenzyl alcohol to analyte of approximately 20:1. A single peak, located at 1224 Da, was obtained from the bacterial spores. The washing liquid and extract solution from the spores were analyzed using electrospray mass spectrometry and subsequent MS/MS product ion experiments. This independent analysis suggests that the measured species represents part of the B. subtilis peptidoglycan. The on-line addition of matrix allows quasi-real-time chemical analysis of individual, aerodynamically sized particles, with an overall system residence time of less than 5 seconds. These results suggest that a MALDI-ATOFMS can provide nearly real-time identification of biological aerosols. Copyright 2000 John Wiley & Sons, Ltd. 相似文献
69.
Four metallated conjugated oligothiophenes,S-1,S-2,S-3 and S-4,with platinum(II)aryleneethynylenes as the electron-rich building block were synthesized to investigate their physicochemical and photovoltaic properties.These small molecules possess fairly low-lying HOMO energy levels which match with the LUMO energy level of the electron acceptor PC70BM([6,6]-phenyl-C71-butyric acid methyl ester).Using the simple process of spin-coating solution fabrication technique,S-1:PC70BM(1:4,w/w)based organic solar cells exhibiting a high Voc of 0.913 V,with a PCE value of 0.88%were developed.In contrast,the OSC device based on S-2:PC70BM(3:7,w/w)displayed a higher PCE of 1.59%with a higher Jsc value of 5.89m A cm–2.The device based on S-4:PC70BM(1:4,w/w)exhibited a PCE value of 1.56%,with a Voc of 0.917 V. 相似文献
70.
Sher Alam Dr. Chokkalingam Anand Kripal Singh Lakhi Prof. Jin‐Ho Choy Wang Soo Cha Dr. Ahmed Elzhatry Prof. Salem S. Al‐deyab Prof. Yutaka Ohya Prof. Ajayan Vinu 《Chemphyschem》2014,15(16):3440-3443
The preparation of size‐controllable Fe2O3 nanoparticles grown in nanoporous carbon with tuneable pore diameters is reported. These hybrid materials exhibit strong non‐linear magnetic properties and a magnetic moment of approximately 229 emu g?1, which is the highest value ever reported for nanoporous hybrids, and can be attributed to the nanosieve effect and the strong interaction between the nanoparticles and the carbon walls. 相似文献