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Anupam Glorious Lobo Abdul Mujeeb Mahammad Nawaz Adeeb Aman A. P. Abdul Basith 《Polymer-Plastics Technology and Engineering》2016,55(16):1713-1719
Elucidation of the structure of naturally existing or synthesized substances is an important criterion in the study of materials to predict the application of the substance. In this study, polylactide was doped with nano-aluminium oxide and nano-cupric oxide with 1 and 3 mg of concentration variants. The interaction between the polymer matrix and the nanoparticles has been studied using Fourier transform infrared. Successful doping of the polymer has been observed. Attention has been drawn to check the intermolecular bonding in films having varying thicknesses, films prepared at higher sonication temperatures, and chemical homogeneity of the doped polymer films. 相似文献
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Talal Al-Wahaibi Mujeeb Smith Panagiota Angeli 《Journal of Petroleum Science and Engineering》2007,57(3-4):334-346
The effect of a drag-reducing polymer (DRP) in the water phase during horizontal oil–water flow was investigated in a 14 mm ID acrylic pipe. Oil (5.5 mPa s, 828 kg/m3) and a co-polymer (Magnafloc 1011) of polyacrylamide and sodium acrylate were used. Two polymer concentrations were tested, 20 ppm and 50 ppm, made from a 1000 ppm master solution. The results showed a strong effect of DRP on flow patterns. The presence of DRP extended the region of stratified flow and delayed transition to slug flow. The addition of the polymer clearly damped interfacial waves. Annular flow changed in all cases investigated to stratified or dual continuous flow, while slug flow changed in most cases to stratified flow. In the cases where the slug and bubble flow patterns still appeared after the addition of the polymer, the oil slugs and bubbles were seen to flow closer together than in the flow without the polymer. The DRP caused a decrease in pressure gradient and a maximum drag reduction of about 50% was found when the polymer was introduced into annular flow. The height of the interface and the water hold up increased with DRP. There were no large differences on pressure gradient and hold up between the two DRP concentrations. Using a two-fluid model it was found that the addition of the polymer results in a decrease in both the interfacial and the water wall shear stresses. 相似文献
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Naeem Ahmad Jan Saad Hassan Kiani Daniyal Ali Sehrai Muhammad Rizwan Anjum Amjad Iqbal Mujeeb Abdullah Sunghwan Kim 《计算机、材料和连续体(英文)》2021,66(1):35-49
In this paper, a low cost, highly efficient and low profile monopole
antenna for ultra-wideband (UWB) applications is presented. A new inverted triangular-shape structure possessing meander lines is designed to achieve a wideband response and high efficiency. To design the proposed structure, three steps
are utilized to achieve an UWB response. The bandwidth of the proposed antenna
is improved with changing meander lines parameters, miniaturization of the
ground width and optimization of the feeding line. The measured and simulated
frequency band ranges from 3.2 to 12 GHz, while the radiation patterns are measured at 4, 5.3, 6 and 8 GHz frequency bands. The overall volume of the proposed
antenna is 26 × 25 × 1.6 mm3
; whereas the FR4 material is used as a substrate
with a relative permittivity and loss tangent of 4.3 and 0.025, correspondingly.
The peak gain of 4 dB is achieved with a radiation efficiency of 80 to 98% for
the entire wideband. Design modelling of proposed antenna is performed in
ANSYS HFSS 13 software. A decent consistency between the simulated and
measured results is accomplished which shows that the proposed antenna is a
potential candidate for the UWB applications. 相似文献
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Yasin Kanbur Mihai Irimia-Vladu Eric D. Głowacki Gundula Voss Melanie Baumgartner Günther Schwabegger Lucia Leonat Mujeeb Ullah Hizir Sarica Sule Erten-Ela Reinhard Schwödiauer Helmut Sitter Zuhal Küçükyavuz Siegfried Bauer Niyazi Serdar Sariciftci 《Organic Electronics》2012,13(5):919-924
We report on the fabrication and performance of vacuum-processed organic field effect transistors utilizing evaporated low-density polyethylene (LD-PE) as a dielectric layer. With C60 as the organic semiconductor, we demonstrate low operating voltage transistors with field effect mobilities in excess of 4 cm2/Vs. Devices with pentacene showed a mobility of 0.16 cm2/Vs. Devices using tyrian Purple as semiconductor show low-voltage ambipolar operation with equal electron and hole mobilities of ~0.3 cm2/Vs. These devices demonstrate low hysteresis and operational stability over at least several months. Grazing-angle infrared spectroscopy of evaporated thin films shows that the structure of the polyethylene is similar to solution-cast films. We report also on the morphological and dielectric properties of these films. Our experiments demonstrate that polyethylene is a stable dielectric supporting both hole and electron channels. 相似文献
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Evidence for alpha-helical conformation of an essential N-terminal region in the human Bcl2 protein 总被引:1,自引:0,他引:1
LC Lee JJ Hunter A Mujeeb C Turck TG Parslow 《Canadian Metallurgical Quarterly》1996,271(38):23284-23288
A region occupying approximately 24 amino acids near the N terminus of human Bcl2 is essential for this cytoplasmic membrane protein's ability to inhibit apoptosis. Systematic mutagenesis of this N-terminal region indicates that only five hydrophobic and aromatic residues within it are specifically required for function. Computerized secondary structure prediction, together with circular dichroism spectroscopy of synthetic peptides, indicates that the region encompassing these five residues has the propensity to take on an alpha-helical conformation in the presence of SDS micelles, which presumably mimic the hydrophobic surfaces of cellular membranes or polypeptides. The five critical residues are predicted to be clustered on one face of this putative helix, where they might serve to mediate protein-protein contacts involved in the multimerization of Bcl2 or in the interaction of Bcl2 with other, as yet unidentified components of the apoptotic pathway. Apparent structural homologues of this helical motif are also present in at least some other anti-apoptotic proteins from the Bcl2 family but not in those family members that tend to potentiate, rather than inhibit, apoptosis. 相似文献
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Schwabegger G Ullah M Irimia-Vladu M Baumgartner M Kanbur Y Ahmed R Stadler P Bauer S Sariciftci NS Sitter H 《Synthetic Metals》2011,(19-20):2058-2062
We report on C(60) based organic field effect transistors (OFETs) that are well optimized for low voltage operation. By replacing commonly used dielectric layers by thin parylene films or by utilizing different organic materials like divinyltetramethyldisiloxane-bis(benzocyclo-butene) (BCB), low density polyethylene (PE) or adenine in combination with aluminum oxide (AlOx) to form a bilayer gate dielectric, it was possible to significantly increase the capacitance per unit area (up to two orders of magnitude). The assembly of metal-oxide and organic passivation layer combines the properties of the high dielectric constant of the metal oxide and the good organic-organic interface between semiconductor and insulator provided by a thin capping layer on top of the AlOx film. This results in OFETs that operate with voltages lower than 500?mV, while exhibiting field effect mobilities exceeding 3?cm(2)?V(-1)?s(-1). 相似文献