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571.
Gupta AK Shakya PD Pardasani D Palit M Dubey DK 《Rapid communications in mass spectrometry : RCM》2005,19(8):975-983
This communication describes the synthesis and gas chromatography/mass spectrometric (GC/MS) analysis of N,N-dialkylphosphoramidic dihalides and alkylphosphonic difluorides, which are synthones of nerve agents. The study was undertaken with a view to developing a spectral database of these compounds for verification purposes of the Chemical Weapons Convention (CWC). The modified synthetic approach reported here has advantages over traditional syntheses in terms of time and yield. GC/MS analysis of these synthones yielded electron ionization (EI) mass spectra and, based on these spectra, generalized fragmentation routes are proposed that rationalize most of the characteristic ions. 相似文献
572.
ABSTRACTIn the present paper, we report an alternative method to model the electro-mechanical instability (EMI) phenomenon of the dielectric elastomeric (DE) actuators. The proposed method is based on a classical continuum mechanics approach followed by the second law of thermodynamics. We first formulate an electro-elastic deformation of a continua through an amended energy function followed by the theory of electro-elasticity. The amended energy function accounts the electrostriction phenomenon for a class of an incompressible isotropic electro-elastic material. In addition, the proposed energy function also overcomes the hurdle of the physical interpretation of the Maxwell stress tensor in large deformation. We then consider that the DE actuators are subjected to a pre-stretching effect through a simple loading with an applied electrical voltage across the thickness. Further, we develop the analytical EMI models for the DE actuators through a new amended energy function. Finally, the obtained EMI models through the proposed method are compared with an existing energy-based method, and also validated with the experimental data existing in the literature. The comparison and validation indicate that the proposed classical method is more realistic as compared to the existing one. 相似文献
573.
Silica gel thin-layer chromatography plates impregnated with macrocyclic antibiotic, vancomycin, as chiral selector were prepared and used for the resolution of (+/-)-verapamil. A mobile phase system of acetonitrile-methanol-water (15:2.5:2.5, v/v) was worked out systematically. The effects of chiral selector, temperature and pH on resolution were also studied. The spots were detected with iodine vapors and the detection limit was found to be 0.074 microg of each enantiomers. 相似文献
574.
The effect of addition of chromium and nickel oxides on the physicochemical properties and performance of V2O5/ZrO2 catalysts was studied for the oxidative dehydrogenation of propane. Addition of chromium oxide increased, whereas addition
of nickel oxide lowered the activity. Selectivity for propene was lower for the doped catalysts. The selectivity was lowered
by higher total acidity as well as the higher concentration of stronger acid sites in doped catalysts. 相似文献
575.
Sustainable existence of solid mercury (Hg) nanoparticles at room temperature and their applications
Villa Krishna Harika Tirupathi Rao Penki Boddapati Loukya Atanu Samanta Gui-Liang Xu Cheng-Jun Sun Ilya Grinberg Francis Leonard Deepak Khalil Amine Doron Aurbach Aharon Gedanken 《Chemical science》2021,12(9):3226
Although liquid mercury (Hg) has been known since antiquity, the formation of stable solid nano forms of Hg at room temperature has not been reported so far. Here, for the first time, we report a simple sonochemical route to obtain solid mercury nanoparticles, stabilized by reduced graphene oxide at ambient conditions. The as-formed solid Hg nanoparticles were found to exhibit remarkable rhombohedral morphology and crystallinity at room temperature. Extensive characterization using various physicochemical techniques revealed the unique properties of the solid nanoparticles of Hg compared to its bulk liquid metal phase. Furthermore, the solid nature of the Hg nanoparticles was studied electrochemically, revealing distinctive properties. We believe that solid Hg nanoparticles have the potential for important applications in the fields of electroanalytical chemistry and electrocatalysis.Formation of the stable solid mercury nanoparticles by acoustic cavitation and their electrochemical activity compared to its bulk liquid metal. 相似文献
576.
The 2H‐1‐benzo/naphthopyran‐2‐one‐4‐yl (un)substituted phenyl‐1,3,4‐oxadiazoles has been synthesized by the oxidative cyclization of benzoic acid hydrazides formed in situ by the condensation of the respective 2H‐1‐benzo/naphthopyran‐2‐one‐4‐carboxaldehyde and (un)substituted monobenzoyl hydrazide in moderate yields. Also, spiro[indoline‐thiozolidine]‐2,4′‐diones has been syhthesized in a similar way from 3‐phenyl‐spiro[3H‐indoline‐3,2′‐thiozolidine]‐2,4′‐(1 H)dione monohydrazide and (un)substituted benzaldehydes. 相似文献
577.
The appearance energy of the [C6H4]+˙ ion from benzonitrile has been measured, using an electron monochromator. The value observed at onset, 12.54±0.03 eV, leads to a heat of formation of 1304±3 kJ mol?1. Possible reasons for widely divergent values reported previously are proposed. 相似文献
578.
Suresh K. Bhargava James Tardio Harit Jani Deepak B. Akolekar Karl Föger Manh Hoang 《Catalysis Surveys from Asia》2007,11(1-2):70-86
Catalytic wet air oxidation (CWAO) is a promising process for removing organic compounds from industrial aqueous streams.
Over the last three decades a significant amount of research has been conducted on various aspects of the process including
catalyst development, catalytic reaction mechanisms and oxidation reaction mechanisms, and the effects of important parameters
such as temperature, pressure and pH on total organic carbon (TOC) removal. The Industrial Chemistry Group at RMIT University
has conducted a significant amount of research on this process over the last several years focussing on organics removal from
three very different industrial aqueous streams: Bayer liquor used in alumina refining; stripped sour water used in oil shale
refining; and pulp and paper effluent used in paper manufacturing. Important results obtained on each of the aforementioned
industrial aqueous streams are discussed in detail in this survey article. 相似文献
579.
A. Krishnamoorthy Vishwanath C. Narayanan T. G. Deepak 《Journal of Applied Mathematics and Computing》2007,25(1-2):389-405
In this paper, we study ak-out-of-n system with single server who provides service to external customers also. The system consists of two parts: (i) a main queue consisting of customers (failed components of thek-out-of-n system) and (ii) a pool (of finite capacityM) of external customers together with an orbit for external customers who find the pool full. An external customer who finds the pool full on arrival, joins the orbit with probability γ and with probability 1- γ leaves the system forever. An orbital customer, who finds the pool full, at an epoch of repeated attempt, returns to orbit with probability δ (< 1) and with probability 1- δ leaves the system forever. We compute the steady state system size probability. Several performance measures are computed, numerical illustrations are provided. 相似文献
580.
We revisit the question whether the critical behavior of sandpile models with sticky grains is in the directed percolation universality class. Our earlier theoretical arguments in favor, supported by evidence from numerical simulations [P.K. Mohanty, D. Dhar, Phys. Rev. Lett. 89 (2002) 104303], have been disputed by Bonachela et al. [Phys. Rev. E 74 (2006) 050102] for sandpiles with no preferred direction. We discuss possible reasons for the discrepancy. Our new results of longer simulations of the one-dimensional undirected model fully support our earlier conclusions. 相似文献