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21.
The effects of host/filler interactions, processing, and morphological development of low percolation threshold (Φc) conducting blends were investigated. It was found that the value of Φc was dramatically reduced by the isolation of the carbon black (CB) conducting filler at the cocontinuous interface of a binary poly(styrene) (PS) and poly(styrene co‐acrylonitrile) (SAN) insulating host, resulting in a multiple percolation effect. Accumulation of the filler at the interface was possible due to the incompatibility of the CB filler with the PS phase and partial compatibility with the SAN phase. The best results were obtained by initially dispersing the CB in the PS phase during melt‐ blending, followed by the addition of the SAN phase. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 3106–3119, 2000 相似文献
22.
Fan HH Guo L Li KF Wong MS Cheah KW 《Journal of the American Chemical Society》2012,134(17):7297-7300
We report the synthesis and investigation of multiphoton absorption properties of a novel series of diphenylamino-end-capped ladder-type oligo(p-phenylene)s which exhibit greatly enhanced and efficient multiphoton (from two- to five-photon) upconverted blue photoluminescence with which the record-high intrinsic three-photon absorption cross-section of 4.56 × 10(-76) cm(6) s(2) in the femtosecond regime has been obtained. Exceptionally efficient two- to five-photon-excited lasing in the blue region has also been demonstrated in which the highest two-photon-excited lasing efficiency of 0.34% has been achieved. 相似文献
23.
Despoina-Eleni Zacharioudaki Ioannis Fitilis Melina Kotti 《Molecules (Basel, Switzerland)》2022,27(15)
Fluorescence spectroscopy is an optical spectroscopic method that has been applied for the assessment of environmental quality extensively during the last 20 years. Most of the earlier works have used conventional light sources in spectrofluorometers to assess quality. Many recent works have used laser sources of light for the same purpose. The improvement of the energy sources and of the higher resolution spectrometers has led to a tremendous increase in applications. The motivation for the present review study is the increasing use of laser sources in environmental applications. The review is divided in two parts. The fundamental principles of fluorescence spectroscopy are described in the first part. The environmental applications are described in the second part. 相似文献
24.
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
25.
H.M. Wong Jian-Bai Xia K.W. Cheah 《Applied Physics A: Materials Science & Processing》1997,64(5):507-509
Received: 10 June 1996/Accepted: 20 October 1996 相似文献
26.
F. Abdullah B. Bouzid M. A. Mahdi C. L. Cheah M. Z. Jamaludin M. K. Abdullah 《Optics & Laser Technology》2004,36(3):1793-190
This paper reports the design of a dual wavelength fibre laser system using a dumbbell shaped configuration. The oscillation of the lasing wavelength is completed via fibre loop mirrors with a tuneable bandpass filter. The output power, side mode suppression ratio and wavelength spacing of the lasers were investigated against the pump power for forward and backward pumping schemes. The output powers of 4.99 and 3.69 dBm at 1545.08 and 1547.28 nm, respectively, for forward pumping scheme. On contrary, the output powers of 1.93 and 2.14 dBm at 1546.12 and 1551.48 nm, respectively, for backward pumping scheme. The peak output powers of less than 1 dB difference are obtained without any adjustment of the intra-cavity loss over a wider spectral range. 相似文献
27.
28.
Wong WY Poon SY Lee AW Shi JX Cheah KW 《Chemical communications (Cambridge, England)》2004,(21):2420-2421
Oligo(fluorenyleneethynylenegermylene)s and their polyplatinynes are synthesized and photophysically characterized; inclusion of heavy germylene bridges greatly boosts the phosphorescence decay rate in metallopolymers. 相似文献
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30.
The adsorption behaviour and the micro- and mesopore size distributions of commercial palm kernel shell activated carbons (PKSAC) and other commercial activated carbon are characterized. The results showed that PKSAC are predominantly microporous materials, where micropores account 68–79% of total porosity. On the other hand, commercial activated carbons: Norit SX Plus, Calgon 12×40, and Shirasagi “A” activated carbons contained high mesopore fraction ranging from 33 to 52%. The analysis showed that the degree of mesoporosity of PKSAC is increased steadily with the decrease of particle size. This is due to the presence of channels interconnect the smaller pores in the interior of smaller particle size PKSAC. The smaller size PKSAC particle that is highly mesoporous has preformed better on the adsorption of larger molecules such as methylene blue. On the other hand, bigger size PKSAC particle has better performance on the adsorption of smaller adsorbates such as iodine. 相似文献