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31.
María Abreu-Sepúlveda Dominique E. Williams Ashfia Huq Chetan Dhital Yunchao Li M. Parans Paranthaman Karim Zaghib A. Manivannan 《Ionics》2016,22(3):317-325
Titanium, tantalum-substituted Li7La3Zr2-xAxO12 (LLZO, A?=?Ta, Ti) garnets, and chromium-substituted La(2/3)-xLi3xTi1-yCryO3 (LLTO) perovskites were prepared by a conventional solid-state reaction and the Pechini processes. The desired crystal phases were obtained by varying the calcination temperature and time, as well as the substitution concentration. All samples indicated decomposition of the precursors when heated above 750 °C and formation of the desired phase after heat treatment at higher temperatures. Neutron diffraction data shows the formation of a predominant cubic phase in the case of Ta-LLZO, and monoclinic phase with minor impurity phases for Cr-LLTO. Ionic conductivity for Ti-LLZO (Li7La3Zr1.4Ti0.6O12), Ta-LLZO (Li6.03La3Zr1.533Ta0.46O12), and Cr-LLTO (La(2/3)-xLi3xTi0.9Cr0.1O3) at room temperature were found to be 5.21?×?10?6, 1.01?×?10?6, and 1.2?×?10?4 S cm?1, respectively. The activation energies of the compounds were determined from the Arrhenius plot and were 0.44 eV (Ti0.6-LLZO), 0.54 eV (Ta0.5-LLZO), and 0.20 eV (Cr0.1-LLTO). 相似文献
32.
33.
Manandhar Suman Sankhe Runali Priya Keerthi Hari Gangadhar Kumar B. Harish Mehta Chetan H. Nayak Usha Y. Pai K. Sreedhara Ranganath 《Molecular diversity》2022,26(5):2793-2811
Molecular Diversity - Wnt signaling pathway is an evolutionarily conserved pathway responsible for neurogenesis, axon outgrowth, neuronal polarity, synapse formation, and maintenance.... 相似文献
34.
Oyer AJ Carrillo JM Hire CC Schniepp HC Asandei AD Dobrynin AV Adamson DH 《Journal of the American Chemical Society》2012,134(11):5018-5021
Applications requiring pristine graphene derived from graphite demand a solution stabilization method that utilizes an easily removable media. Using a combination of molecular dynamics simulations and experimental techniques, we investigate the solublization/suspension of pristine graphene sheets by an equimolar mixture of benzene and hexafluorobenzene (C(6)H(6)/C(6)F(6)) that is known to form an ordered structure solidifying at 23.7 °C. Our simulations show that the graphene surface templates the self-assembly of the mixture into periodic layers extending up to 30 ? from both sides of the graphene sheet. The solvent structuring is driven by quadrupolar interactions and consists of stacks of alternating C(6)H(6)/C(6)F(6) molecules rising from the surface of the graphene. These stacks result in density oscillations with a period of about 3.4 ?. The high affinity of the 1:1 C(6)H(6)/C(6)F(6) mixture with graphene is consistent with observed hysteresis in Wilhelmy plate measurements using highly ordered pyrolytic graphite (HOPG). AFM, SEM, and TEM techniques verify the state of the suspended material after sonication. As an example of the utility of this mixture, graphene suspensions are freeze-dried at room temperature to produce a sponge-like morphology that reflects the structure of the graphene sheets in solution. 相似文献
35.
Dhital C Yamani Z Tian W Zeretsky J Sefat AS Wang Z Birgeneau RJ Wilson SD 《Physical review letters》2012,108(8):087001
We report neutron scattering experiments probing the influence of uniaxial strain on both the magnetic and structural order parameters in the parent iron pnictide compound, BaFe2As2. Our data show that modest strain fields along the in-plane orthorhombic b axis can affect significant changes in phase behavior simultaneous to the removal of structural twinning effects. As a result, we demonstrate in BaFe2As2 samples detwinned via uniaxial strain that the in-plane C4 symmetry is broken by both the structural lattice distortion and long-range spin ordering at temperatures far above the nominal (strain-free) phase transition temperatures. Surprising changes in the magnetic order parameter of this system under relatively small strain fields also suggest the inherent presence of magnetic domains fluctuating above the strain-free ordering temperature in this material. 相似文献
36.
Chetan K. Modi Parthiv M. Trivedi Sanjeev K. Gupta Prafulla K. Jha 《Journal of inclusion phenomena and macrocyclic chemistry》2012,74(1-4):117-127
A series of zeolite-Y encapsulated hybrid catalysts, [M(STCH)·xH2O]-Y have been prepared by encapsulating Schiff base complexes [where M?=?Mn(II), Fe(II), Co(II), Ni(II); (x?=?3) and Cu(II); (x?=?1); H2STCH?=?salicylaldehyde thiophene-2-carboxylic hydrazone] in zeolite-Y matrix by flexible ligand method. These hybrid materials have been characterized by various physico-chemical techniques such as ICP-OES, elemental analyses, (FT-IR and electronic) spectral studies, BET, scanning electron micrographs, thermal analysis and X-ray powder diffraction patterns. X-ray powder diffraction analysis reveals that the structural integrity of the mother zeolite in the hybrid material remained intact upon immobilization of the complex. Density functional theory is employed to calculate the relaxed structure, bond angle, bond distance, dihedral angle, difference of highest occupied molecular orbital and lowest unoccupied molecular orbital energies gap and electronic density of states of ligand and their neat transition metal complexes. The hybrid materials are active catalysts for the hydroxylation of phenol using hydrogen peroxide (30% H2O2) as an oxidant in order to selectively synthesize catechol or hydroquinone, amongst them [Cu(STCH)·H2O]-Y shown the highest % of selectivity towards catechol (81.3%). 相似文献
37.
Ravi Vithalani Dikin S. Patel Chetan K. Modi Vaishali Sharma Prafulla K. Jha 《应用有机金属化学》2020,34(4):e5500
Graphene oxide (GO) supported transition metal complexes are apprised as sturdy and everlasting heterogeneous catalysts. GO surface was functionalized with 3-triethoxysilylpropylamine (TSPA) and this amino functionalized GO (A-f-GO) nanocomposite with vanadyl Schiff base complex (VO-f-GO) was prepared and to give credence of its potentiality, it was chosen for the selective epoxidation of styrene using environmentally benign 30% H2O2 to styrene oxide (SO). To evade the detrimental exposure of “inborn” water, a selective high boiling and potent hygroscopic solvent, ethylene glycol was chosen to make this transformation productively successful. With the assistance of theoretical studies, we have probed the effect of H2O2 on to structural properties, binding mechanism and electronic properties of the catalyst and substrate. Adsorption energy (Ead), energy band gap (Eg) and HOMO-LUMO were also calculated. Based on DFT calculations, resonance Raman and UV/Vis studies, we confirmed the formation of metal-peroxo species and propose the plausible catalytic pathway. The influence of the diverse experimental parameters, like substrate to oxidant mole ratio, catalyst concentration, type of solvents, solvent amount, time, temperature and oxidant were tested. A clear relationship was found between different reaction parameters like solvent amount, oxidant, catalyst concentration and temperature etc. and product distribution. This heterogeneous catalyst yielded styrene oxide as nearly the sole product (selectivity = 98.7%) with a conversion value of 99.2% in the oxidation of styrene with hydrogen peroxide in ethylene glycol. 相似文献
38.
Ghule A Bhongale C Chang H 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2003,59(7):1529-1539
Thermal dehydration and condensation processes of disodium hydrogen phosphate dodecahydrate (Na2HPO4*12H2O) were monitored by thermo-Raman spectroscopy (TRS). Various hydrated forms Na2HPO4*12H2O, Na2HPO4*8H2O, Na2HPO4*7H2O, Na2HPO4*2H2O, Na2HPO4*H2O and Na2HPO4 were observed, followed by condensation of Na2HPO4 to sodium pyrophosphate (Na4P2O7) in a dynamic thermal process. Representative Raman spectra of all the hydrated forms Na2HPO4*12H2O, Na2HPO4*8H2O, Na2HPO4*7H2O, Na2HPO4*2H2O, Na2HPO4*H2O and Na2HPO4 were detected in both H2O and PO4(3- )regions are reported. The thermo-Raman intensity (TRI) thermogram also showed systematic loss of water in five steps of dehydration, with the differential TRI thermogram in agreement shows five dips corresponding to the five steps of dehydration, respectively. Thermogravimetry (TG) and differential thermogravimetry (DTG) are in harmony with the results of TRS, though, the two could not resolve the steps involved. 相似文献
39.
Rai B Sathish P Malhotra CP Pradip Ayappa KG 《Langmuir : the ACS journal of surfaces and colloids》2004,20(8):3138-3144
Molecular dynamics simulations incorporating explicit gold atoms in the simulations have been carried out for alkanethiol self-assembled monolayers chemisorbed on the Au(III) surface. The structural properties of the monolayer are evaluated for two force fields: one in which the Au--S--C bond is fixed (FF I), and the other in which it is flexible (FF II). The influence of these force fields on the structural properties of HS(CH2)14CH3 on the structured Au surface is compared at different temperatures. FF I yields greater tilt angles and a smaller film thickness when compared with FF II. Both of the force fields predict that the tilt angles do not follow a monotonic decrease with temperature but show minima around 200 K. Simulations carried out at different chain lengths at 300 K reveal that FF II predicts a greater film thickness than FF I; however, the difference is within 1 A. 相似文献
40.
Krishna S. Indalkar Chetan K. Khatri Ganesh U. Chaturbhuj 《Tetrahedron letters》2017,58(22):2144-2148
A straightforward, mild, efficient, and environmentally benign protocol for a three-component Strecker reaction of aldehydes or ketones, amines, and trimethylsilyl cyanide catalyzed by sulfated polyborate has been described to afford α-aminonitriles under solvent-free reaction conditions. The major advantages of the present method are excellent yields, shorter reaction time, simple experimental procedure, easy workup procedure, recyclability of the catalyst, solvent-free reaction conditions and ability to tolerate a variety of functional groups which gives economical as well as ecological rewards. 相似文献