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21.
N. Punitha R. Ganapathi Sundaram K. Vijayalakshmi R. Rengasamy J. Elangovan 《印度化学会志》2022,99(9):100667
The effectiveness of 1H?pyrazole?3,5?dicarboxylic acid 5?benzyl ester 3?phenyl ester (PCBPE) as a preventer for deterioration of IS 513 Gr. D steel in 1 M HCl medium is evaluated via weight loss, electrochemical impedance, and polarization techniques. Kinetic and thermodynamic parameters assessed the feasibility of the adsorption process at diverse temperatures. The inhibition action on mild steel has been enhanced with increasing PCBPE concentration. It is found from the polarization studies that PCBPE behaves as mixed type inhibitor in HCl medium. The adsorption process of PCBPE on mild steel surface from acid environment is favoured Langmuir adsorption isotherm. The shielding efficiency of PCBPE has been enhanced at elevated concentrations, and it has been diminished at amplified temperatures. The Atomic Force Microscope (AFM), Scanning Electron Microscope (SEM), and Energy Dispersive Spectrum (EDS) were used to establish a surface characterization of metal specimens. A quantum chemical analysis of electron density distributions in the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) demonstrated how the inhibitor undergoes adsorption on mild steel in 1 M HCl. All experimental findings substantiate the corrosion mitigation performance of PCBPE on mild steel in acidic environments. 相似文献
22.
Rajendran Duraisamy Ramalingam Ganapathy Sundaram Esakkimuthu Jawahar Paulraj Sivakumar Vaithilingam Mahian Omid Bellos Evangelos 《Journal of Thermal Analysis and Calorimetry》2020,140(1):33-51
Journal of Thermal Analysis and Calorimetry - The solar collector (reflector and receiver) is the primary device being used in the concentrating solar power technologies for tapping the solar... 相似文献
23.
We present a new method to obtain high-mobility three-dimensional electron gas systems. We have achieved control of carrier density and of carrier profile by growth of the first remotely-doped parabolic potential well structures. Computer-controlled molecular beam epitaxy is used to grow a layer of ultra-fine superlattices with a programmable composition gradient. This produces conduction-band potentials which, in the absence of doping, are equivalent to the potential profiles of fixed charge distributions. When conduction electrons are introduced into these graded wells through remote doping of the barrier regions, they distribute themselves in such a way as to produce a uniform chemical potential at thermal equilibrium. We illustrate through computer simulations employing Fermi statistics that electrons introduced into a wide parabolic potential well distribute themselves uniformly. More significantly, the carrier distribution in the well is remarkably insensitive to the dopant sheet charge in the barrier, the more so at lower temperatures. We have fabricated remotely-doped graded potential well structures of the proposed type by molecular beam epitaxy. These structures exhibit the above effects. Measured mobilities of such three-dimensional electron gases grown using the GaAs/AlxGa1−xAs system are higher than those of bulk-doped GaAs doped to give the same uniform electron concentration. 相似文献
24.
Microexplosions in tellurite glasses 总被引:2,自引:0,他引:2
S.K. Sundaram C.B. Schaffer E. Mazur 《Applied Physics A: Materials Science & Processing》2003,76(3):379-384
Femtosecond laser pulses were used to produce localized damage in the bulk and near the surface of baseline, Al2O3-doped and La2O3-doped sodium tellurite glasses. Single or multiple laser pulses were non-linearly absorbed in the focal volume by the glass,
leading to permanent changes in the material in the focal volume. These changes were caused by an explosive expansion of the
ionized material in the focal volume into the surrounding material, i.e. a microexplosion. The writing of simple structures
(periodic array of voxels, as well as lines) was demonstrated. The regions of microexplosion and writing were subsequently
characterized using scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS) and atomic force microscopy (AFM).
Fingerprints of microexplosions (concentric lines within the region and a concentric ring outside the region), due to the
shock wave generated during microexplosions, were evident. In the case of the baseline glass, no chemistry change was observed
within the region of the microexplosion. However, Al2O3-doped and La2O3-doped glasses showed depletion of the dopant from the edge to the center of the region of the microexplosions, indicating
a chemistry gradient within the regions. Interrogation of the bulk- and laser-treated regions using micro-Raman spectroscopy
revealed no structural change due to the microexplosions and writing within these glasses.
Received: 27 December 2001 / Accepted: 9 July 2002 / Published online: 25 October 2002
RID="*"
ID="*"Corresponding author. +1-509/376-3108, E-mail: sk.sundaram@pnl.gov 相似文献
25.
26.
Sheila Sundaram 《Journal of Algebraic Combinatorics》1999,9(3):251-269
We present a class of subposets of the partition lattice
n
with the following property: The order complex is homotopy equivalent to the order complex of
n
– 1, and the S
n
-module structure of the homology coincides with a recently discovered lifting of the S
n
– 1-action on the homology of
n
– 1. This is the Whitehouse representation on Robinson's space of fully-grown trees, and has also appeared in work of Getzler and Kapranov, Mathieu, Hanlon and Stanley, and Babson et al.One example is the subposet P
n
n
– 1 of the lattice of set partitions
n
, obtained by removing all elements with a unique nontrivial block. More generally, for 2 k n – 1, let Q
n
k
denote the subposet of the partition lattice
n
obtained by removing all elements with a unique nontrivial block of size equal to k, and let P
n
k
=
i = 2
k
Q
n
i
. We show that P
n
k
is Cohen-Macaulay, and that P
n
k
and Q
n
k
are both homotopy equivalent to a wedge of spheres of dimension (n – 4), with Betti number
. The posets Q
n
k
are neither shellable nor Cohen-Macaulay. We show that the S
n
-module structure of the homology generalises the Whitehouse module in a simple way.We also present a short proof of the well-known result that rank-selection in a poset preserves the Cohen-Macaulay property. 相似文献
27.
It is shown that, if one takes account of the non-stationary nature of the background equilibrium, then ion acoustic waves in a two-temperature, collisional, fully ionized plasma are stable. 相似文献
28.
29.
An analysis of the semiclassical regime of the quantum-classical transition is given for open, bounded, one-dimensional chaotic dynamical systems. Environmental fluctuations-characteristic of all realistic dynamical systems-suppress the development of a fine structure in classical phase space and damp nonlocal contributions to the semiclassical Wigner function, which would otherwise invalidate the approximation. This dual regularization of the singular nature of the semiclassical limit is demonstrated by a numerical investigation of the chaotic Duffing oscillator. 相似文献
30.
A tight-binding representation of the kicked Harper model is used to obtain an integrable semiclassical Hamiltonian consisting of "quantized" bands of orbits. New bands appear when renormalized Harper parameters exceed integer multiples of pi/2. Orbits with frequencies commensurate with the kicking frequency are shown to correlate with classical accelerator modes in the original kicked problem. Signatures of this superdiffusive and, in our view, resonant transport are seen in both classical and quantum behavior. An important feature of our analysis is the emergence of a natural scaling relating classical and quantum couplings which is necessary for establishing correspondence. 相似文献