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Daryoosh Beigzadeh 《大分子反应工程》2007,1(3):331-337
In high‐throughput research, it is essential to use “right data” and “meaningful parameters” to reach reliable conclusions. The complexity and the large amount of data obtained from each set of experiments make the analysis of reaction data a nontrivial task. The important role of reaction kinetic modeling in the analysis of polymerization reaction data is discussed, and it is shown that the application of traditional methods for the determination of catalyst productivity can be misleading. Reaction kinetic modeling provides meaningful parameters for data analysis, gives complete information about the polymerization kinetic profile, and makes it possible to evaluate assumptions and hypotheses.
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Lobat Tayebi Masoud Mozafari Rita El‐khouri Parvaneh Rouhani Daryoosh Vashaee 《Photochemistry and photobiology》2014,90(3):517-521
Light induced cis/trans isomerization in the family of merocyanine (MC) dyes offers a recyclable proton pumping ability which can potentially be used in hybrid bio‐electronic devices. In this article, a hexadecyl MC dye is embedded in lipid molecules to make a macromolecular configuration of a lipid/hexadecyl MC membrane. Lipid molecules play a critical role in stabilizing the dye in a membrane structure for practical use in energy devices. In this study, we first examined the proton pumping characteristic of the lipid/hexadecyl MC membrane in a conventional photoelectrochemical cell. Next, a major modification in the cell was introduced by eliminating I2/I‐electrolyte which resulted in a two‐fold increase in the open circuit voltage compared with that of the conventional cell. In addition, the charging time in the new cell was reduced approximately four orders of magnitude. This research demonstrated that the newly designed lipid‐ MC cell can act as a promising bioelectronic device based on the green energy of photoinduced MC dye proton pumping. 相似文献
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Daryoosh Beigzadeh Joo B.P. Soares Thomas A. Duever 《Journal of polymer science. Part A, Polymer chemistry》2004,42(12):3055-3061
This investigation studied the solution polymerization of ethylene in Isopar E in a semibatch reactor using CGC‐Ti as catalyst and methylalumoxane (MAO) and tris(pentaflourophenyl)borane [B(C6F5)3] as cocatalysts. The effects of cocatalyst type and amount on the chain microstructure were investigated. 13C NMR and gel permeation chromatography were used to determine the long‐chain branching (LCB) content and molecular weight distribution (MWD), respectively, of the samples. It was observed that higher concentrations of MAO increased the LCB content and decreased the molecular weight of the polymer. On the other hand, increasing the amount of B(C6F5)3 lowered the LCB content, increased the molecular weight, and broadened MWD significantly. We believe that this approach can be used as an efficient way to control the microstructure of polyolefins made with these catalytic systems. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3055–3061, 2004 相似文献
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Mehdi Razavi Mohammadhossein Fathi Omid Savabi Daryoosh Vashaee Lobat Tayebi 《Surface and interface analysis : SIA》2014,46(6):387-392
Magnesium alloys are promising biomaterials as biodegradable implant for orthopedic applications. However, their low corrosion resistance and poor bioactivity have prohibited their implant applications. In order to enhance these two properties, a nano‐grain merwinite coating was prepared on magnesium alloy. Its corrosion and the bioactivity behavior were characterized with electrochemical and immersion tests. The results showed that the nano‐grain merwinite coating can improve both the corrosion resistance and the bioactivity of the magnesium alloy making it an appropriate material for biodegradable bone implants. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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In this paper we present a detailed theory of electron and thermoelectric transport perpendicular to heterostructure superlattices. This nonlinear transport regime above barriers is also called heterostructure thermionic emission. We show that metal-based superlattices with tall barriers can achieve a large effective thermoelectric figure of merit (ZT > 5 at room temperature). A key parameter to achieving high performance is the nonconservation of lateral momentum during the thermionic emission process. Conservation of lateral momentum is a consequence of translational symmetry in the plane of the superlattice. We also discuss the use of nonplanar barriers and embedded quantum dot structures to achieve high thermoelectric conversion efficiency. 相似文献
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Daryoosh Beigzadeh Joo B. P. Soares Thomas A. Duever 《Macromolecular rapid communications》1999,20(10):541-545
The solution polymerization of ethylene in Isopar E in a semi-batch reactor using combined CGC-Ti and Et[Ind]2ZrCl2 catalysts was studied. Methylaluminoxane (MAO) and tris(pentafluorophenyl)borane were used as co-catalysts. Samples were analyzed by 13C NMR and gel permeation chromatography (GPC) for their branching content and molecular weight distribution. It was shown that there was an optimum ratio of CGC-Ti/Et[Ind]2ZrCl2 that maximizes the number of long-chain branches of the formed polyethylene. 相似文献
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Polyethylene with long‐chain branches can be produced with certain metallocene catalysts, such as monocyclopentadienyl derivatives, by incorporation of macromonomers formed in‐situ into the polymer backbone. This investigation demonstrates how dual metallocene systems can be used to control and enhance the level of long chain branching of polyethylene made with these catalysts. For instance, a catalyst that favors long chain branch formation, such as Dow's constrained geometry catalyst, can be combined with another metallocene that produces macromonomers at a faster rate. In this way, the concentration of macromonomers in the reactor increases, thus favoring the formation of long chain branches. This leads, however, to a complex microstructural control problem, since both the molecular weight and long chain branch distribution are affected simultaneously by the presence of the second catalyst. Several mathematical models will be used to describe this challenging microstructural control problem. 相似文献
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Mohammad Neshat Daryoosh Saeedkia Safieddin Safavi-Naeini 《International Journal of Infrared and Millimeter Waves》2008,29(9):809-822
A semi-analytical method based on distributed source transmission line model is proposed to analyze a traveling-wave terahertz
photomixer integrated with a coplanar stripline waveguide. Multilayer spectral domain method along with complex image technique
have been applied to calculate the distributed voltage source element in the transmission line representation. To find the
coupled terahertz signal along the coplanar stripline, the transmission line equations are solved. The results obtained from
the proposed method are verified by the full wave analysis. 相似文献