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161.
In the current endeavor, polystyrene (PS) was first functionalized to get nitro-substituted polystyrene (PS-NO2) and then the matrix was further modified into an amino-functional polystyrene (PS-NH2). Later the effect of addition of acid functional graphite (F-G) on the mechanical, thermal, morphological, and non-flammability properties of composite series (PS/F-G 0.01–0.5, PS-NO2/F-G 0.01–0.5, and PS-NH2/F-G 0.01–0.5) was scrutinized. The composites were prepared using solution processing and melt blending. According to FESEM, the solution mixing of graphite prevented the nano-filler aggregation in the matrix relative to melt-processed hybrids. There was considerable augment in the tensile strength and tensile modulus of solution-processed amino-functional material (32.8–39.6?MPa and 3.8–5.7?GPa, respectively) with functional graphite loading relative to PS/F-G 0.01–0.5 and PS-NO2/F-G 0.01–0.5 prepared. Adding up of F-G also improved the thermal stability of solution-processed composites, and the enhancement was maximum in the case of PS-NH2/F-G 0.01–0.5 with 10% weight loss in the range 446–477 °C. In solution system, cone calorimetry results show a decrease in the PHHR values of the composites relative to pure PS and nitro-functional matrix. PS-NH2/F-G 0.5 had PHHR value of 462 kW/m2, and the reduction of HRR values was also escorted by decrease in ignition time. Thermal, mechanical, and non-flammability results of solution-processed systems were found to be enhanced compared with melt-blended system depicting the advantage of the technique used. 相似文献
162.
Farook Ahmad Ahmad Pauzi Mohd Yusof Martina Bainbridge Sulaiman Ab Ghani 《Electroanalysis》2007,19(5):541-548
Hydrogen peroxide (H2O2) was the main types of many peroxides produced in living mammalian cells that consumed oxygen. In the brain, the main source of H2O2 was the superoxide dismutase (SOD)‐catalyzed reaction in mitochondria. However, the level of H2O2 would be elevated through administration of control drugs and alcohol by dopamine metabolism of monoamine oxidase. In this study, a H2O2 microsensor was used to investigate the level of H2O2 in the brain striatum after administration of methamphetamine (MAP), morphine (MrP) or ethanol (Eth). The placement of microsensor in the brain was done at coordinates A/P 1.1 from bregma, M/L+2.6 and D/V‐1.5. A working potential of +0.05 V vs. Ag/AgCl was applied. The H2O2 concentration was measured direct from the current generated by its catalytic reaction at the electro active surface of the electrode. A significant increase of H2O2 level was observed after 7 successive injections of the controlled drugs or alcohol. The initial measurement of H2O2 is essential as excess dosage of H2O2 during treatment will contribute to the formation of neurotoxin oxygenated radicals. The H2O2 was the precursor of O2? and OH radicals. Thus, this study provided a mean to monitor H2O2 level in the brain. 相似文献
163.
Haider Abbas K.P. Tiwary L.S.S. Singh Mohd. Zulfequar Z.H. Zaidi M. Husain 《Journal of luminescence》2005,114(2):162-166
The sol-gel process is a technique which provides a low-temperature route for the preparation of organic dye-doped porous silica glass. Extended UV transmission was observed for HCl-catalysed sol-gel silica. Properties of a solute may differ greatly between a free solution and that solution confined in pores of a sol-gel glass. Absorption and fluorescence properties of sulforhodamine 640-doped silica samples prepared by sol-gel process were investigated. In the TEOS-derived gel, the emission of the dye does not shift during aging but exhibits a large change during drying. The emission maximum of sulforhodamine 640 blue shifts was discussed as a function of increasing rigidity of the surrounding matrix. 相似文献
164.
165.
166.
and
provided a variety of
and
alkaloids as well as novel ring-opened indole alkaloids including leuconolam (6), rhazinilam (8) and 5,21-dihydrorhazinilam (9). Facile acid and base reactions of leuconolam lead to ring reclosure products. Physical and spectral data of norfluorocurarine (
), norfluorocurarine-Nb-oxide (
), eburnamine (2), kopsinine (5) and epileuconolam (7) as well as some derivatives of leuconolam are also provided. 相似文献
167.
168.
The law of variation for mean Hubble’s parameter with average scale factor, in an anisotropic Bianchi type V cosmological space–time, is discussed within the frame work of Lyra’s manifold. The variation of Hubble’s parameter, which gives a constant value of deceleration parameter, generates two types of solutions for the average scale factor; one is the power-law and the other one is of exponential form. Using these two forms, new classes of exact solutions of the field equations have been found for a Bianchi type V space–time filled with perfect fluid in Lyra’s geometry by considering a time-dependent displacement field. The physical and kinematical behaviors of the singular and non-singular models of the universe are examined. Exact expressions for look-back time, luminosity distance and event horizon versus redshift are also derived and their significance are discussed in detail. It has been observed that the solutions are compatible with the results of recent observations. 相似文献
169.
The composite of silver-modified lithium manganese oxide were prepared using thermal decomposition method of different mole
ratio. Structural characterization was carried out by X-ray diffraction (XRD). XRD analysis revealed different patterns as
the content of the dopant in the spinel increases. Phase analysis shows that Ag particles were dispersed on the LiMn2O4 surface instead of entering the spinel structure. On the other hand, the electrochemical behavior of cathode powder was examined
by using two-electrode test cells consisting of a cathode, metallic lithium as anode, and a solid polymer electrolyte of 0.87PEO-0.13LiCF3SO3-0.10DBP. According to the electrochemical tests results, the influence of the Ag additive content on the electrochemical
properties of Ag/LiMn2O4 composites is clearly shown. 相似文献
170.
A Lanczos potential for an arbitrary Petrov type D vacuum spacetimes, using the compacted spin coefficient formalism (or GHP-formalism),
has been obtained; which in turn leads to a solution of Weyl-Lanczos equations. 相似文献