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311.
Bera L.K. Choi W.K. Tan C.S. Samanta S.K. Maiti C.K. 《Electron Device Letters, IEEE》2001,22(8):387-389
Thermal stability and strain relaxation temperature of strained Si 0.91Ge0.09 layers has been investigated using double crystal x-ray diffraction (DCXRD). High quality gate oxynitride layers rapid thermally grown on strained Si0.91Ge0.09 using N2O and the split N2O cycle technique below the strained relaxed temperature is reported. A positive fixed oxide charge density was observed for N2O and split-N2 O grown films. The O2 grown films exhibit a negative fixed oxide charge. The excellent improvements in the leakage current, breakdown field and charge-to-breakdown value of the N2O or split-N2O grown films were achieved compared to pure O2 grown films 相似文献
312.
Two new cadmium(II) complexes of the empirical formulae [Cd(SMDTC)3] · 2NO3 (1) and [Cd(SBDTC)2] · 2NO3 (2) have been synthesized and characterized by elemental analyses, UV–Vis, IR, 1H NMR and TGA techniques. In complex 1, the six coordination sites around cadmium are occupied by three neutral SMDTC molecules with N and S donor atoms from each ligand molecule, whereas in complex 2 the cadmium center is four coordinated with two relatively larger SBDTC ligands chelating with N and S donor atoms in the neutral thione form. In the solid state, thermal gravimetric analysis shows that both complexes are relatively volatile in nature and undergo facile thermal decomposition above 120 °C to form the metal sulfide followed by stepwise loss of ligand molecules. The crystal and molecular structure of complex 1 has been established by the X-ray diffraction method. The central cadmium(II) atom has an octahedral geometry with three five-membered chelate rings formed by SMDTC ligands. The crystal structure consists of parallel layers of cations and anions. The SMDTC molecules in cations are arranged with their N donor groups directed towards the anion layer in an alternating fashion and form hydrogen bonds with the O atoms of the anion. 相似文献
313.
L. K. Bera S. K. Ray D. K. Nayak N. Usami Y. Shiraki C. K. Maiti 《Journal of Electronic Materials》1999,28(2):98-104
Gas source molecular beam epitaxy has been employed for the growth of a high quality strained-Si layer on a completely relaxed
step-graded Si1−xGex buffer layer. As-grown strained-Si layers have been characterized using secondary ion mass spectroscopy, Rutherford backscattering
spectroscopy, atomic force microscopy, and spectroscopic ellipsometry for the determination of composition, thickness, crystalline
quality, and surface roughness. Heterojunction conduction and valence band offsets (ΔEc, ΔEυ) of strained-Si/SiGe heterostructure have been determined from measured threshold voltages of a strained-Si channel p-metal
oxide semiconductor field effect transistor (MOSFET) fabricated using grown films. MOS capacitance-voltage profiling has been
employed for the extraction of strained-Si layer thickness and apparent doping profile in the device. 相似文献
314.
Paramita Bera Syamali Chakrabarti Nitin K. Gaikwad Nithya N. Kutty Monica Barman 《Natural product research》2019,33(3):435-438
Emitted scent volatile profile of an orchid species Zygopetalum maculatum was studied using dynamic headspace sampling technique with four different adsorbent matrices, namely Porapak Type Q polymer (mesh size: 80/100), Tenax (mesh size: 60/80), activated charcoal and graphite. In addition, developmental variations in scent emissions and endogenous volatile levels were also investigated. Gas chromatography-mass spectrometry analysis revealed the presence of 21 volatile compounds in the headspace, which was predominantly enriched with benzenoid compounds. Among these benzenoids, o-diethylbenzene and p-diethylbenzene were the major compounds followed by benzyl acetate and methyl salicylate. Among the phenylpropanoid compounds, 2-phenylethyl acetate was the major volatile. However, as compared to benzenoids, the quantity was much lesser, indicating the inclination of phenylalanine flux towards benzenoid pathway. The outcome of this study has the implications in enhancing fragrance and vase life of orchids of the Sikkim Himalaya region and thus may further help to meet the growing market demand. 相似文献
315.
Based on the statistical concept of the median, we propose a quantum uncertainty relation between semi-interquartile ranges of the position and momentum distributions of arbitrary quantum states. The relation is universal, unlike that based on the mean and standard deviation, as the latter may become non-existent or ineffective in certain cases. We show that the median-based one is not saturated for Gaussian distributions in position. Instead, the Cauchy-Lorentz distributions in position turn out to be the one with the minimal uncertainty, among the states inspected, implying that the minimum-uncertainty state is not unique but depends on the measure of spread used. Even the ordering of the states with respect to the distance from the minimum uncertainty state is altered by a change in the measure. We invoke the completeness of Hermite polynomials in the space of all quantum states to probe the median-based relation. The results have potential applications in a variety of studies including those on the quantum-to-classical boundary and on quantum cryptography. 相似文献
316.
317.
Swathi Swaminathan Prof. Jitendra K. Bera Dr. Manabendra Chandra 《Angewandte Chemie (International ed. in English)》2023,62(7):e202215933
Using visible photoexcitation of gold nanospheres we successfully demonstrate the simultaneous harvesting of plasmon-induced multiple hot holes in the complete oxidative scission of the C=C bond in styrene at room temperature to selectively form benzaldehyde and formaldehyde, which is a reaction that requires activation of multiple substrates. Our results reveal that, while extraction of hot holes becomes efficient for interband excitation, harvesting of multiple hot holes from the excited Au nanospheres becomes prevalent only beyond a threshold light intensity. We show that the alkene oxidation proceeded via a sequence of two consecutive elementary steps; namely, a binding step and a cyclic oxometallate transition state as the rate-determining step. This demonstration of plasmon-excitation-mediated harvesting of multiple hot holes without the use of an extra hole transport media opens exciting possibilities, notably for difficult catalytic transformations involving multielectron oxidation processes. 相似文献
318.
Synthesis of nanocrystalline CdS from cadmium(II) complex of S-benzyl dithiocarbazate as a precursor
The single X-ray crystal structure of the cadmium(II)–S-benzyl dithiocarbazate (SBDTC) complex, [Cd(SBDTC)Cl2]2, is reported. The compound has been found to be an effective single-source precursor for the preparation of CdS nanocrystals (NCs) via solvothermal method. CdS NCs including spheres and rods were prepared at a relatively low temperature by thermolysis of the precursor using chelating solvent like ethylene glycol (EG), ethylenediamine (EN), hydrazine hydrate (HH) or in a mixture of EG and EN. The influence of solvent, temperature and reaction time was investigated on the size and morphology of the NCs. Use of EG afforded spherical CdS NCs while EN uniquely yielded rod-shaped NCs, and mixture of spheres and rods are obtained from the mixture of EN and EG with a ratio 0.2 (v/v: EN/EG). UV–visible spectroscopy established pronounced quantum confinement with enhanced band gap and XRD analyses revealed hexagonal crystal phase for so obtained CdS NCs. The NCs were also characterized by transmission electron microscopy (TEM), photoluminescence spectroscopy (PL), energy-dispersive X-ray spectroscopy (EDS) and FTIR. The possible formation mechanism for the anisotropic growth of NCs was also discussed. 相似文献
319.
Kinetics of aqua ligand substitution from cis-[Ru(bpy)2(H2O)2]2+ by three vicinal dioximes, namely dimethylglyoxime (L1H), 1,2-cyclohexane dionedioxime (L2H) and α-furil dioxime (L3H) have been studied spectrophotometrically in the 45–60 °C temperature range. The rate constants increase with increasing
dioxime concentration and approach a limiting condition. We propose the following rate law for the reaction in the 3.5–5.5
pH range: where k
2 is the interchange rate constant from outer sphere to inner sphere complex and K
E is the outer sphere association equilibrium constant. Activation parameters were calculated from the Eyring plots for all
three systems: ΔH
≠ = 59.2 ± 8.8, 63.1 ± 6.8 and 69.7 ± 8.5 kJ mol−1, ΔS
≠ = −122 ± 27, −117 ± 21 and −99 ± 26 J K−1 mol−1 for L1H, L2H and L3H, respectively. An associative interchange mechanism is proposed for the substitution process. Thermodynamic parameters calculated
from the temperature dependence of the outer sphere association equilibrium constants give negative ΔG
0 values for all the systems studied at all the temperatures (ΔH
0 = 30.05 ± 2.5, 18.9 ± 1.1 and 11.8 ± 0.2 kJ mol−1; ΔS
0 = 123 ± 8, 94 ± 3 and 74 ± 1 J K−1 mol−1 for L1H, L2H and L3H, respectively), which also support our proposition. 相似文献
320.
Nitin Kumar Mukesh K. Alaria Udaybir Singh A. Bera T. P. Singh A. K. Sinha 《Journal of Infrared, Millimeter and Terahertz Waves》2010,31(5):601-607
A beam tunnel for a 42 GHz, 200 kW gyrotron for an Indian TOKAMAK system has been designed. The initial design of the beam
tunnel has been carried out on the basis of the required electron beam parameters at the interaction cavity and the electron
beam simulation of the magnetron injection gun. The design optimization of the beam tunnel has been done with the help of
3-D simulation software CST-Microwave Studio. In the simulation, the absorption, the reflection and the transmission of RF
power by the beam tunnel have been analyzed. Three different lossy ceramics, Al2O3–SiC, AlN–SiC and BeO–SiC have been investigated during the simulation. The simulation results obtained with CST-Microwave
Studio have been validated with another 3-D simulation software HFSS. The Q value of the beam tunnel for different ceramic
material has also been analyzed to investigate the parasitic mode excitation in the beam tunnel. 相似文献