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191.
Kinetics of the extraction of V(IV) from acidic sulfate medium by Cyanex 301 dissolved in kerosene has been investigated using a constant interfacial area stirred cell with laminar flow (Lewis cell). Reaction orders with respect to different concentration terms, rate constant, activation energy, entropy change in activation, and the enthalpy change in activation have been measured at a phase circulation speed of 3 Hz. The rate equation at 293 K is F (kmol/m2s) = 10?7.02 (1 + 0.025[V(IV)]?1)?1 (1 + 398[H+])?1 (1 + 0.10 [HA]o?1)?1 (1 + 3.16 [SO42?]). Based on the experimental results, the mechanism of extraction has been proposed. 相似文献
192.
Subir Kumar Sarkar Anupam Karmakar Ashis Kumar De 《Czechoslovak Journal of Physics》2001,51(3):249-256
Small-signal ac transport of degenerate one-dimensional hot electrons in quantum wires of GaAs and In0.53Ga0.47As is studied for lattice temperatures of 77 K and 300 K. The carrier energy loss via polar optic phonons and momentum losses via polar optic phonons, acoustic phonons and ionized impurities are included in the calculations. Alloy disorder scattering in momentum loss is additionally incorporated for (In,Ga)As. The consideration of nonequilibrium optical phonons or hot phonons is found to enhance the 3dB cut-off frequency (f3dB) considerably, where the ac mobility falls to 0.707 of its low frequency value. f3dB is generally higher for (In,Ga)As quantum wire than for GaAs. 相似文献
193.
paper presents a novel approach to model and represent chipless radio-frequency identification (RFID) frequency signatures. The approach involves the geometrical representation of chipless RFID frequency signatures in a signal space. A small set of orthonormal basis functions is derived using singular value decomposition in order to represent the 2 b possible tag signatures of a b-bit chipless tag. Each tag signature is represented as a point in an L-dimensional signal space, and minimum distance detection is used to extract the information bit sequence of the tag. Detection error probability is also examined through analytical derivations and Monte Carlo simulation. A set of 3-bit tags were fabricated to validate the approach. Experimental results show that the new approach is capable of accurately detecting information contained in chipless RFID tags. This approach offers a solid mathematical framework for developing novel detection methods for chipless tags. 相似文献
194.
195.
P.-Y. Chan M. Gogna E. Suarez F. Al-Amoody S. Karmakar B. I. Miller E. K. Heller J. E. Ayers F. C. Jain 《Journal of Electronic Materials》2013,42(11):3259-3266
An indium gallium arsenide quantum-dot-gate field-effect transistor using Zn0.95Mg0.05S as the gate insulator is presented in this paper, showing three output states which can be used in multibit logic applications. The spatial wavefunction switching effect in this transistor has been investigated, and modeling simulations have shown supporting evidence that additional output states can be achieved in one transistor. 相似文献
196.
197.
Epitaxial bilayered thin films composed of ferromagnetic La0.6Sr0.4MnO3 and ferroelectric 0.7Pb (Mg1/3Nb2/3)O3–0.3(PbTiO3) were fabricated on LaAlO3 (100) substrates by pulsed laser ablation. Ferroelectric, ferromagnetic and magneto–dielectric characterizations performed earlier indicated the possible existence of strain-mediated magneto–electric coupling in these biferroic heterostructures. In order to investigate their true remnant polarization characteristics, usable in devices, room-temperature polarization versus electric field, positive-up negative-down (PUND) pulse polarization studies and remnant hysteresis measurements were carried out. The PUND and remnant hysteresis measurements revealed the significant contribution of the non-remnant component in the observed polarization hysteresis response of these heterostructures. 相似文献
198.
Ayan Maity Dr. Jung‐Suk Choi Dr. Thomas S. Teets Dr. Nihal Deligonul Prof. Dr. Anthony J. Berdis Prof. Dr. Thomas G. Gray 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(47):15924-15932
Fundamental study of enzymatic nucleoside transport suffers for lack of optical probes that can be tracked noninvasively. Nucleoside transporters are integral membrane glycoproteins that mediate the salvage of nucleosides and their passage across cell membranes. The substrate recognition site is the deoxyribose sugar, often with little distinction among nucleobases. Reported here are nucleoside analogues in which emissive, cyclometalated iridium(III) complexes are “clicked” to C‐1 of deoxyribose in place of canonical nucleobases. The resulting complexes show visible luminescence at room temperature and 77 K with microsecond‐length triplet lifetimes. A representative complex is crystallographically characterized. Transport and luminescence are demonstrated in cultured human carcinoma (KB3‐1) cells. 相似文献
199.
E. Suarez M. Gogna F. Al-Amoody S. Karmakar J. Ayers E. Heller F. Jain 《Journal of Electronic Materials》2010,39(7):903-907
This paper presents preliminary data on quantum dot gate nonvolatile memories using nearly lattice-matched ZnS/Zn0.95Mg0.05S/ZnS tunnel insulators. The GeO
x
-cladded Ge and SiO
x
-cladded Si quantum dots (QDs) are self-assembled site-specifically on the II–VI insulator grown epitaxially over the Si channel
(formed between the source and drain region). The pseudomorphic II–VI stack serves both as a tunnel insulator and a high-κ dielectric. The effect of Mg incorporation in ZnMgS is also investigated. For the control gate insulator, we have used Si3N4 and SiO2 layers grown by plasma- enhanced chemical vapor deposition. 相似文献
200.
Tirtha Som Basudeb Karmakar 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2010,75(2):640-646
Dichroic Sm3+: Au-antimony glass nanocomposites are synthesized in a new reducing glass (dielectric) matrix (mol%) K2O–B2O3–Sb2O3 (KBS) by a single-step melt-quench technique involving selective thermochemical reduction. X-ray diffraction (XRD) and selected area electron diffraction (SAED) results indicate that Au0 nanoparticles are grown along the (2 0 0) plane direction. The transmission electron microscopic (TEM) image reveals the elliptical Au0 nanoparticles having major axis range 12–17 nm. Dichroic behavior is due to elliptical shape of Au0 nanoparticles of aspect ratio ~1.2. Au0 NPs of concentration of 0.03 wt% (4.1 × 1018 atoms/cm3) drastically enhances the intensity (~7-folds) of electric dipole 4G5/2 → 6H9/2 red transition (636 nm) of Sm3+ ions and then attenuates with further increase in Au0 concentration. The magnetic dipole 4G5/2 → 6H5/2 green (566 nm) and 4G5/2 → 6H7/2 orange (602 nm) transitions remain almost unaffected by presence of nano Au0. Local field enhancement (LFE) induced by Au0 SPR and energy transfer (ET) from fluorescent Au0 → Sm3+ ions are found to be responsible for the enhancement while reverse ET from Sm3+ → Au0 and optical re-absorption due to Au0 SPR for attenuation. 相似文献