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81.
Shashank Tripathi Achu Chandran Tilak Joshi Anil Kumar Ajay Dhar 《Liquid crystals》2013,40(9):1255-1262
In this article, a newly synthesised ferroelectric liquid crystal (FLC) material, namely LAHS 22, has been characterised. The characterisation of the FLC material has been performed using dielectric relaxation spectroscopy, differential scanning calorimetry and polarisation optical microscopy. We observed an enhancement in the dielectric and electro-optical properties of the FLC material by incorporating gold nanoparticles (GNPs)-decorated multiwalled carbon nanotubes (MWCNTs). The GNPs-decorated MWCNTs cause an increment in dielectric dispersion (up to kHz), absorption, spontaneous polarisation and rotational viscosity of the FLC material. The pure and GNPs-decorated MWCNTs doped FLC cells were analysed by means of various dielectric spectroscopic and optical measurements. The observed enhancement in the dielectric and electro-optical properties of the FLC material has also been studied with concentration of GNPs-decorated MWCNTs in FLC material. The GNPs-decorated MWCNTs/FLC composites are not only of fundamental importance, but also useful materials for device applications such as liquid crystal displays and memory devices. 相似文献
82.
George Cordoyiannis Patricia Losada-Pérez Chandra Shekhar Pati Tripathi Brigita Rožič Uroš Tkalec Vassilios Tzitzios 《Liquid crystals》2013,40(11):1419-1426
The phase transition behaviour of the chiral liquid crystal CE6 doped with spherical surface-functionalised CdSe nanoparticles has been examined by means of high-resolution adiabatic scanning calorimetry and polarising microscopy. The addition of nanoparticles results in an essentially stabilised blue phase III. The phase diagram is displayed upon heating and cooling and the enthalpy changes involved in the conversion between the blue phases are determined. The dispersion of functionalised nanoparticles is prominent for the stabilisation of blue phase III, which is potentially useful for applications, especially if applied on liquid crystals that exhibit blue phases close to room temperature. 相似文献
83.
A new phenanthroindolizidine alkaloid, 3-O-demethyl tylophorinidine (VI), was isolated from the aerial (leaves and stem) parts of Tylophora indica and characterized using different spectral techniques. Gel chromatography and reverse phase preparative HPLC were used for sample purification. The new alkaloid, VI, was screened for anticancer activity against a panel of different cancer cell lines and it showed significant anticancer activity with IC50 value in the range of 0.89?C1.40 ??M. 相似文献
84.
Dr. Dongpeng Yan Dr. Dejan‐Krešimir Bučar Dr. Amit Delori Bhavnita Patel Dr. Gareth O. Lloyd Prof. William Jones Prof. Xue Duan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(25):8213-8219
Multi‐component organic nanocrystals that are comprised of two or more supramolecular building blocks can be used to extend the design and assembly scope of solid molecular materials. Herein, we report the use of ultrasonication to prepare halogen‐bonded stilbene‐based nano‐cocrystals that exhibit different photoemission properties, including one‐ and two‐phonon emission and fluorescence lifetimes, relative to those of macrodimensional crystals. The structural transformation from nano‐cocrystals into nanocrystals upon heating results in a luminescence red‐shift from greenish blue to yellow. The temperature‐dependent ratiometric luminescence may allow such nano‐cocrystals to be used as fluorescent sensors and thermosensitive materials. 相似文献
85.
A mathematical theory of time-dependent dislocation mechanics of
unrestricted geometric and material nonlinearity is reviewed. Within
a ``small deformation" setting, a suite of simplified and
interesting models consisting of a nonlocal Ginzburg Landau
equation, a nonlocal level set equation, and a nonlocal generalized
Burgers equation is derived. In the finite deformation setting, it
is shown that an additive decomposition of the total velocity
gradient into elastic and plastic parts emerges naturally from a
micromechanical starting point that involves no notion of plastic
deformation but only the elastic distortion, material velocity,
dislocation density and the dislocation velocity. Moreover, a
plastic spin tensor emerges naturally as well. 相似文献
86.
A simple and convenient approach for the synthesis of unsymmetrical diaryl chalcogenides (Te, Se, and S) has been developed by copper-catalyzed cross-coupling reaction of organoboronic acid with diaryl dichalcogenide in ethanol using NaBH4 in air or oxygen. The present methodology is highly practical for the synthesis of unsymmetrical diaryl tellurides with various functionalities such as –NO2, –F, –Br, and –COOH that have been obtained in good to excellent yields. Methodology is also effective for the synthesis of unsymmetrical diaryl selenides and sulfides. Moreover, symmetrical diaryl selenides have also been obtained from arylboronic acids using elemental selenium powder under optimized reaction conditions. The use of NaBH4 is the key for the development of milder reaction conditions, which enable the construction of unsymmetrical diaryl chalcogenides from boronic acid substrates in ethanol at room temperature. 相似文献
87.
A facile, single pot diastereoselective access to seven and eight membered aza-heterocycles was developed by using β-lactam-synthon approach. The developed protocol does not involve the typical intricacies viz. the use of expensive transition metal catalysts and high boiling solvents, associated with the convenient protocols. 相似文献
88.
Nitro‐Substituted Bishomocubanes: Synthesis,Characterization, and Application as Energetic Materials 下载免费PDF全文
Sohan Lal Dr. Sundaram Rajkumar Amit Tare Dr. Sasidharakurup Reshmi Prof. Dr. Arindrajit Chowdhury Prof. Dr. Irishi N. N. Namboothiri 《化学:亚洲杂志》2014,9(12):3533-3541
Several high‐energy‐density strained polycyclic compounds nitromethyl‐l,3‐bishomocubane (NMBHC), nitromethylene‐1,3‐bishomocubane (NMyBHC), and bis(nitromethyl)‐1,3‐bishomocubane (DNTMBHC), which were synthesized for the first time from bishomocubanone, hold potential for application as standalone fuels in liquid bipropellant systems or as additives in liquid and solid propellant formulations. DFT analysis at the B3LYP/6‐31G(d) level of theory was employed to optimize the geometries of the compounds and to determine their densities, heats of formation, and various thermodynamic properties. The density specific impulse, determined by using equilibrium thermodynamics, demonstrated an improvement of 75 s for NMBHC and NMyBHC over standard hydrocarbons. The specific impulse with ammonium perchlorate showed an improvement of 25–30 s over hydroxy‐terminated polybutadiene. Thermogravimetric analysis revealed that NMBHC, NMyBHC, and DNTMBHC evaporated readily with activation energies of 58.8, 69.2, and 74.5 kJ mol?1, respectively. 相似文献
89.
90.