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61.
RF sputtered p-type nickel oxide (NiO) thin film exhibiting tunable semiconductor character which in turns enhanced its functional properties. NiO thin film with high hole mobility is developed as a potential matrix for the realization of glucose biosensor. NiO thin film prepared under the optimized deposition conditions offer good electrical conductivity (1.5 × 10−3 Ω−1-cm−1) with high hole mobility (2.8 cm2 V−1 s−1). The bioelectrode (GOx/NiO/ITO/glass) exhibits a low value of Michaelis–Menten constant (Km = 1.05 mM), indicating high affinity of the immobilized GOx toward the analyte (glucose). Due to the high surface coverage (2.32 × 10−7 mol cm−2) of the immobilized enzyme on to the NiO matrix and its high electrocatalytic activity, the prepared biosensor exhibits a high sensitivity of 0.1 mA (mM−1-cm−2) and a good linearity from 25 to 300 mg dL−1 of glucose concentration with fast response time of 5 s. Various functional properties of the material (mobility, crystallinity and stress) are found to influence the charge communication feature of NiO thin film matrix to a great extent, resulting in enhanced sensing response characteristics. 相似文献
62.
Cicerone MT Zhong Q Johnson J Aamer KA Tyagi M 《The journal of physical chemistry letters》2011,2(12):1464-1468
We show that the short-time behavior of time-resolved fluorescence Stokes shifts (TRSS) are similar to that of the intermediate scattering function obtained from neutron scattering at q near the peak in the static structure factor for glycerol. This allows us to extract a Debye-Waller (DW) factor analog from TRSS data at times as short as 1 ps in a relatively simple way. Using the time-domain relaxation data obtained by this method we show that DW factors evaluated at times ≥ 40 ps can be directly influenced by α relaxation and thus should be used with caution when evaluating relationships between fast and slow dynamics in glassforming systems. 相似文献
63.
Clusters of high aspect ratio, high surface area anatase-TiO2 nanotubes with a typical nanotube outer diameter of about 18 nm, wall thickness of approximately 5 nm and length of 5-10 μm were synthesized, in powder form, by breakdown anodization of Ti foils in 0.1 M perchloric acid, at 10 V (299 K) and 20 V (∼275 and 299 K). The surface area, morphology, structure and band gap were determined from Brunauer Emmet Teller method, field emmission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman, photoluminescence and diffuse reflectance spectroscopic studies. The tubular morphology and anatase phase were found to be stable up to 773 K and above 773 K anatase phase gradually transformed to rutile phase with disintegration of tubular morphology. At 973 K, complete transformation to rutile phase and disintegration of tubular morphology were observed. The band gap of the as prepared and the annealed samples varied from 3.07 to 2.95 eV with increase in annealing temperature as inferred from photoluminescence and diffuse reflectance studies. 相似文献
64.
Keka R. Chakraborty S. M. Yusuf P. S. R. Krishna M. Ramanadham A. K. Tyagi 《Pramana》2004,63(2):251-255
We have synthesized polycrystalline La0.95Nd0.05CrO3 sample by doping the La-site of LaCrO3 with Nd and its magnetic properties have been studied using DC magnetization and neutron diffraction techniques. DC magnetization
study shows a paramagnetic to a weak ferromagnetic-like transition at ∼295 K followed by signatures of a spin reorientation
phenomenon at 233 and 166 K and, finally a transition to an antiferromagnetic-like phase at ∼21 K. Low-temperature neutron
diffraction measurements confirm a weak ferrimagnetic ordering of Cr3+ moments at all temperatures below 295 K. 相似文献
65.
66.
67.
Purple colored single crystals of the β-modification of Li3TiF6 have been prepared by heating an appropriate mixture of LiF and TiF3 at 820°C under an argon atmosphere. β-Li3TiF6 crystallizes in C2/c with a = 14.452(2) Å, b = 8.798(1) Å, c = 10.113(1) Å and β = 96.30(1)º. The structure is isotypic to β-Li3VF6 and contains isolated compressed TiF6 octahedra (dTi–F = 1.91–2.01 Å). Magnetic properties of β-Li3TiF6 were studied and discussed. Band structure calculations and calculations of the Madelung part of the lattice energy, MAPLE, were performed to discuss the chemical bonding. 相似文献
68.
Powder samples of the new oxide fluoride V2GeO4F2 have been obtained by the reaction of appropriate amounts V2O3, VF3, and GeO2 at 700°C for 18 h in an argon-filled sealed platinum tube. V2GeO4F2 crystallizes in the space group Pnma with a=9.336(1), b=8.898 (1), and c=4.912 (1) Å. The structure has been refined from X-ray powder diffraction data using the Rietveld method (Rint=5.5% and Rp=9.8%). The structure of V2GeO4F2 exhibits close packed layers of the anions with an ordering of O and F. The characteristic building units are discrete GeO4 tetrahedra with Ge-O distances of 1.75-1.80 Å. The V are coordinated by four O and two F to form VO4F2 octahedra connected via two common edges to give zigzag chains. These chains are linked via corners to form a three-dimensional network. The temperature dependence of the magnetic susceptibility of V2GeO4F2 indicates antiferromagnetic correlations. 相似文献
69.
Farheen N. Sayed Srungarpu N. Achary Sudhanshu·K. Deshpande Balasubhramanian Rajeswari Ramakant M. Kadam Sandhya Dwebedi Arun K. Nigam Avesh K. Tyagi 《无机化学与普通化学杂志》2014,640(10):1907-1921
Polycrystalline samples of La2MMnO6 (M = Co and Mg) were prepared by a combined gel‐combustion and high temperature reaction method. The samples were annealed in different oxygen partial pressure (pO2) and characterized by powder XRD, SQUID magnetometry, ac impedance spectroscopy, and electron paramagnetic resonance techniques. Monoclinic (P21/n) and rhombohedral (R$\bar{3}$ ) lattices were observed for La2CoMnO6 and La2MgMnO6, respectively. On annealing in inert atmosphere, La2MgMnO6 partially converted to monoclinic La2CoMnO6 type structure, whereas no structural change was observed in La2CoMnO6. Dielectric studies of La2CoMnO6 indicated relaxor like behavior with polaronic conduction, which systematically decreased with the increase in pO2 of the annealing atmosphere. Magnetic studies indicated multiple ferromagnetic phase transitions in La2CoMnO6 and a spin‐glass like phase transition in La2MgMnO6. The fraction of ferromagnetic phases of La2CoMnO6 was significantly dependent on the annealing environments. The variations of magnetic and dielectric properties of samples were related to the fluctuation of oxidation state of transition metal ions and oxygen vacancies in the samples. 相似文献
70.
Different substituted 2‐chloromethylpyridyl derivatives (6a–d) were oxidized with mCPBA to give the respective 2‐chloromethylpyridine‐N‐oxide derivatives (7a–d) at low temperature, which on condensation with 2‐mercapto‐1H‐benzimidazole (8a–c) in the presence of aprotic solvents give the 2‐[[(pyridin‐2‐yl‐1‐oxide)methyl]sulfanyl]‐1H‐benzimidazole (9a–d) in good yield. Finally, 9a–d oxidized with mCPBA in chlorinated solvent gives a mixture of 2‐[[(pyridin‐2‐yl‐1‐oxide)methyl]sulfonyl]‐1H‐benzimidazole (3a–d, 10%) and 2‐[[(pyridin‐2‐yl‐1‐oxide) methyl]sulfinyl]‐1H‐benzimidazole (4a–d, 90%) derivatives. 相似文献