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121.
We demonstrate strong photonic thermal rectification effect between polar dielectrics plate and the composite metamaterials containing nonspherical polar dielectric nanoparticles with small volume fractions.Thermal rectification efficiency is found to be adjusted by the volume fractions and the nanoparticles’shape,and it can be as large as 80%when the polar dielectric nanoparticles are spherical in shape and are in the dilute limit with the volume fraction f=0.01.Physically,there exists strong electromagnetic coupling between the surface phonon polariton mode of polar dielectrics plate and the localized surface phonon polariton mode around polar dielectric nanoparticles.The results provide alternative new freedom for regulating energy flow and heat rectification efficiency in the near field,and may be helpful for design of multiparameter adjustable thermal diodes. 相似文献
122.
Abdul Rasheed Mohammed Srinivasa Rao Ravella Shankar Reddy Gagginapally Narsimha Bogaraju Ramakrishna V.S. Nirogi 《Green Chemistry Letters and Reviews》2014,7(2):150-157
Synthetic routes for 5-amino-6-chlorochroman-8-carboxylic acid 1 a key intermediate for several potent 5-HT4 agonists have been explored. An efficient, high yielding, and a concise synthetic route has been established with significant modifications to the earlier reported synthetic protocols, where we have avoided the use of toxic and corrosive reagents and reduced the reaction temperature from reflux to room temperature wherever is possible. We have also reduced the number of steps to reach the target compound and avoided the use of silica gel column purifications. 相似文献
123.
124.
125.
We examine the possibility of rolling tachyon to play the dual role of inflaton at early epochs and dark matter at late times.
We argue that enough inflation can be generated with the rolling tachyon either by invoking the large number of branes or
brane world assisted inflation. However, reheating is problematic in this model.
On leave from Jamia Millia Islamia, New Delhi 110 025, India 相似文献
126.
Uzma Rasheed Mughal Rashad Mehmood Abdul Malik Bakhat Ali Rasool Bakhsh Tareen 《Helvetica chimica acta》2012,95(1):100-105
Sparins A–C ( 1 – 3 , resp.), three new flavonoids, were isolated from the CHCl3 subfraction of the EtOH extract of the whole plant of Spiraea brahuica, along with 3′,7‐di‐O‐methylquercetin ( 4 ) and luteolin 7‐β‐D ‐glucopyranoside ( 5 ), reported for the first time from this species. The structures of the new compounds were elucidated by spectroscopic techniques including MS and 2D‐NMR spectroscopy. 相似文献
127.
Tabish Qureshi Sushanta Dattagupta 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1994,31(1):135-142
A stochastic model is introduced to study the transient magnetic field (TF) experienced by the nuclei of fast ions traversing a ferromagnetic medium. The field is assumed to arise primarily from the bound electrons of the ion, polarized by the internal magnetic field of the ferromagnetic specimen. Spin-flip scattering is considered to be the dominant mechanism for polarization transfer from the host to the ion. Electron capture and loss mechanisms are also taken into account in a phenomenological manner. An analytical expression is derived for the TF which depends on the electron capture and loss cross-sections. The result for the perturbation factor is shown to be more general than that derived by Abragam and Pound and reduces to their result in the appropriate limit. 相似文献
128.
A number of dinitroanilines on reaction with sodium hydride in dimethylformamide produced the sodium salt which, on further reaction with carbon disulfide, cyclized to nitrobenzothiazolinethiones. In several cases benzothiazolinethione sulfides and benzothiazolinethione disulfides were also isolated. 相似文献
129.
Deep eutectic solvents formed between choline chloride and carboxylic acids: versatile alternatives to ionic liquids 总被引:1,自引:0,他引:1
Abbott AP Boothby D Capper G Davies DL Rasheed RK 《Journal of the American Chemical Society》2004,126(29):9142-9147
Deep Eutectic Solvents (DES) can be formed between a variety of quaternary ammonium salts and carboxylic acids. The physical properties are significantly affected by the structure of the carboxylic acid but the phase behavior of the mixtures can be simply modeled by taking account of the mole fraction of carboxylic acid in the mixture. The physical properties such as viscosity, conductivity, and surface tension of these DES are similar to ambient temperature ionic liquids and insight into the cause of these properties is gained using hole-theory. It is shown that the conductivity and viscosity of these liquids is controlled by ion mobility and the availability of voids of suitable dimensions, and this is consistent with the fluidity of other ionic liquids and molten salts. The DES are also shown to be good solvents for metal oxides, which could have potential application for metal extraction. 相似文献
130.
Kuriakose S Vijayan KK Shaji S Eappen SM Nair KP Rasheed TM 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2004,60(10):2283-2286
The near infrared overtone absorption spectrum of liquid phase nitromethane in the spectral region deltaV = 2-5 is reported. The observed spectrum is analysed using local mode model. It is shown that the observed CH local mode overtones and local-local combinations are well predicted by a C(3V) coupled oscillator Hamiltonian. 相似文献