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81.
Kristina Pickl Jan Götz Klaus Iglberger Jayant Pande Klaus Mecke Ana-Sunčana Smith Ulrich Rüde 《Journal of computational science》2012,3(5):374-387
We simulate the self-propulsion of devices in a fluid in the regime of low Reynolds numbers. Each device consists of three bodies (spheres or capsules) connected with two damped harmonic springs. Sinusoidal driving forces compress the springs which are resolved within a rigid body physics engine. The latter is consistently coupled to a 3D lattice Boltzmann framework for the fluid dynamics. In simulations of three-sphere devices, we find that the propulsion velocity agrees well with theoretical predictions. In simulations where some or all spheres are replaced by capsules, we find that the asymmetry of the design strongly affects the propelling efficiency. 相似文献
82.
Günlük Oktay Kalagnanam Jayant Li Minhan Menickelly Matt Scheinberg Katya 《Journal of Global Optimization》2021,81(1):233-260
Journal of Global Optimization - Decision trees have been a very popular class of predictive models for decades due to their interpretability and good performance on categorical features. However,... 相似文献
83.
We consider two parallel strategies for randomized restart algorithms. Given a set of available algorithms, one can either choose the best performing algorithm and run multiple copies of it in parallel (single algorithm portfolio), or choose some subset of algorithms to run in parallel (mixed algorithm portfolio). It has been previously shown in the literature that the latter approach may provide better results. In this paper we investigate the extent of such improvement. 相似文献
84.
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86.
Ignaty Leshchiner Natalia Boiko Jayant Kumar Robert M. Richardson Aziz Muzafarov Valery Shibaev 《Colloid and polymer science》2013,291(4):927-936
Amphiphilic carbosilane dendrimers with novel architectural layout have been synthesized. These dendrimers contain peripheral groups consisting of covalently bound promesogenic fragments and hydrophilic (oligoethyleneglycolic) linkages which are connected to a carbosilane core in two distinct ways: as spacer or as tail arrangement. Such molecules have a block structure where the hydrophilic and hydrophobic blocks are distributed within the dendrimer forming layers of different polarity. The hydrophilic layer is either enclosed between two hydrophobic parts of the molecule or is situated on the periphery. The synthetic strategy for achieving these structures is described. The interfacial properties of the dendrimers were studied and the influence of the dendritic structure’s organization on the Langmuir film formation process is assessed. 相似文献
87.
Ravi Mosurkal Lynne A. Samuelson Arti Tewari Arthur C. Watterson Virinder S. Parmar Jayant Kumar 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(12):1228-1232
Aromatic dianhydrides have been identified as potential candidates for crosslinking with biocatalytically synthesized siloxane copolymers containing a functional amino group on the isophthalate moieties. We present the synthesis, characterization, thermal and flame retardant properties of this novel class of crosslinked organo-siloxane copolymers. We also discuss the effect of the concentration of one of the crosslinkers, 1,2,4,5-benzenetetracarboxylic dianhydride (DAH), on thermal decomposition and flame retardant properties using thermogravimetric analysis (TGA) and pyrolysis combustion flow calorimetry (PCFC) studies. The char yields were improved in all the polymers crosslinked with the various aromatic dianhydrides. The heat release capacity of a polymer crosslinked with 20% DAH, compared to the pure polymer, was tremendously reduced from 190 J/gK to 100 J/gK. The decomposition kinetics from TGA showed that the crosslinked polymer is thermally more stable than the non-crosslinked polymer. 相似文献
88.
Vijayendra Kumar Bhavna Gupta Pramod K. Sharma Ravi Mosurkal Virinder S. Parmar Jayant Kumar 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(12):1199-1204
The great synthetic flexibility of organosilicone polymers, their ease of processing, low cost, and nontoxic nature present an attractive alternative solution over current flame retardant materials. Novozyme-435 catalyzed amidation reaction with silicone-based oligomer was carried out to scale up the synthesis of co-polymer which was fully characterized from its detailed spectroscopic studies. Synthesized co-polymer was compounded in polyolefins for flame retardant applications. Nanoclay [Cloisite 20A, 2C18 MMT (dimethylditallowammonium-/dimethyldioctadecylammonium-modified montmorillonite)] was used as a potential additive in co-polymer, which was then blended with polyolefins to improve their thermal as well as flame retardant properties. The present work provides an initial exciting basis for the enzymatic synthesis of silicon based co-polymers in bulk and their flame retardant applications. 相似文献
89.
Timothy Ponrathnam Junghwan Cho Pradeep Kurup Ramaswamy Nagarajan Jayant Kumar 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(12):1031-1037
Quartz Crystal Microbalance (QCM) based sensors have been used extensively to detect trace amounts of organic chemical vapors. These devices typically incorporate a polymer coating as an active layer that can bind the analytes of interest. Analyte adsorption causes a shift in the resonant frequency of the device proportional to the amount of adsorbed material. Currently some of the polymer coatings used in these sensors utilize hydrogen bonding to adsorb analytes. Dipole-dipole type interactions can also be utilized to promote interaction of the analytes with the polymer coating. Polymer coating containing segments that have a permanent molecular dipole can interact with explosive taggants. In this study, novel polypropylene glycol based polymers that incorporate both hydrogen bonding moieties and segments having large permanent dipole moment (p-nitroazobenzene functional groups) were synthesized and tested. The precursor polymer was prepared by the polymerization of the diglycidyl ether end functionalized polypropylene glycol macromer and aniline. The precursor polymers were post functionalized by an azo-coupling reaction. The sensor response to saturated vapors of o-nitrotoluene, nitrobenzene and 2,4 dinitrotoluene (DNT) saturated vapors was evaluated. Incorporation of p-nitroazobenzene moieties in the polymer increased the sensitivity of detection of the analytes. These studies offer new possibilities for using combination of interactions to improve the sensitivity of the QCM based sensors in the detection of nitroaromatic materials. 相似文献
90.
Ke Yang Yanping Wang Aloke Jain Lynne Samulson Jayant Kumar 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(12):1261-1264
Time of flight method (TOF) is used to measure the electron and hole mobility of a spin coated regioregular poly(3‐hexylthiophene) (P3HT) film. We find that both electron and hole have the same mobility (about 3.8~3.9×10?4 cm2/Vs) at an applied field of 120 kV/cm. It is demonstrated in this paper that the electron‐hole recombination process may prevent the electron transport in the material due to the fact that the carrier recombination time is much shorter than the transit time. 相似文献