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991.
Using physical experiments we investigated the evolution of thermally driven melt patterns in a semi-infinite solid crystalline phase subjected to uniform heating from one side, maintaining melting temperature. We treat the melt initiation phenomenon theoretically in the perspective of two-phase interactions on the microscopic level, and propose a new reaction–diffusion model based on the prey–predator dynamics. This model predicts the fractal behavior of melt fronts observed in the experiments. 相似文献
992.
Inside Cover: Aggregation‐Induced Emission and Sensing Characteristics of Triarylborane–Oligothiophene–Dicyanovinyl Triads (Chem. Eur. J. 48/2016) 下载免费PDF全文
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995.
Dr. Amrita Sikder Dr. Debes Ray Dr. Vinod K. Aswal Prof. Dr. Suhrit Ghosh 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(44):10464-10471
Programmable assembly of biomolecules is a fast growing research area that aims to emulate nature's elegance in creating numerous hierarchical self-assembled structures, which are responsible for unimaginably difficult biological functions. Protein assembly is a particularly challenging task, owing to their structural diversity, conformational heterogeneity, and high molecular weight. This article reveals the ability of a supramolecular structure-directing unit (SSDU) to regulate the entropically favourable supramolecular assembly of a covalently conjugated protein (bovine serum albumin (BSA)) to produce well-defined protein-decorated micelles with remarkably high thermal stability, suppression of the thermal denaturation of the protein, and retention of enzymatic activity. Furthermore, a SSDU-appended thermo-responsive poly(N-isopropylacrylamide) (PNIPAM) co-assembles with the SSDU–BSA conjugate because, in both cases, assembly was primarily driven by specific molecular recognition between the SSDUs. However, the resulting supramolecular protein–polymer conjugate exhibits distinctly different polymersome structure to that of the micellar particle produced by the protein-SSDU conjugate. In this case, the enzymatic activity can be significantly suppressed above the lower critical solution temperature of supramolecularly conjugated PNIPAM, possibly due to collapse of the de-solvated polymer chains on the protein surface. 相似文献
996.
Palladium-based composites are widely used as a heterogeneous catalyst in carbon–carbon coupling reactions and in catalytic converters used in the car industry. In this work, we demonstrate a simple, green and scalable synthesis procedure to obtain palladium (Pd) based heterogeneous catalyst. Surface functionalized silica microparticles were obtained in one-step by spray-drying a colloidal suspension of silica nanoparticles and gum arabic, an environmental-friendly biopolymer. Subsequently, palladium nanoparticles were reduced and attached to the substrate by gum arabic. The as-synthesized composite was characterized by field-emission scanning electron microscopy (FESEM), energy-dispersive x-ray spectroscopy (EDS), x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), small angle x-ray scattering (SAXS), and high-resolution transmission electron microscopy (HR-TEM). The Pd@SiO2 composite was used as a catalyst in the reduction reaction of 4-nitrophenol by sodium borohydride. The catalyst showed good recycling properties. The present environmental-friendly approach for fabrication of Pd-based heterogeneous catalyst circumvents various complex chemical steps involved in conventional chemical methods and could be generalized for the production of ceramic or magnetite-based Pd composites. 相似文献
997.
This investigation presents numerical treatment of governing equations pertaining to thermosolutal flow within an annulus and an application of a model describing the important physical phenomenon as found in muffle furnace. The inner side of the annulus is exposed to high temperature and high solute concentration while the outer side of the annulus is maintained at low temperature and low solute concentration. Darcy-Brinkman-Forchheimer model is used to study the flow, heat and solute transfer in a non-Darcian saturated porous media. The solution is obtained upon application of control volume integration. Modified MAC method is used for the numerical solution of governing equations. Gradient dependent consistent hybrid upwind scheme of second order (GDCHUSSO) is used for discretization of the convective terms. The parameters such as Rayleigh-Darcy number, Darcy number, buoyancy ratio and width ratio, that govern the flow phenomenon have been identified and their effects are critically examined. The fluid flow pattern in the annular space and the associated heat and mass transfer are conceptualized from the obtained isoconcentration, isotherm and flowline contour maps. 相似文献
998.
S. Sarkar 《The European Physical Journal B - Condensed Matter and Complex Systems》2009,67(4):559-564
We study the dissipation physics of a one dimensional mesoscopic
superconducting quantum interference device array using the
field-theoretical renormalization group
method. We observe length scale dependent, superconductor-insulator
quantum phase transition at very low temperature and also observe
the dual behavior
of the system for higher and lower values of magnetic field.
At a critical magnetic field, we also observe a critical behavior
where the resistance is
independent of length. 相似文献
999.
Kaushik Sarkar Sovan K. Singha Shital K. Chattopadhyay 《Tetrahedron: Asymmetry》2009,20(15):1719-1721
A general route to α-, β- and γ-pyrrole-branched α-amino acid derivatives has been developed, which featured a one-pot ring-closing metathesis and aromatization reaction as the key step. 相似文献
1000.