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121.
Naveen?KumarEmail author V. K.?Tripathi B. K.?Sawhney 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2005,32(1):63-68
A fast rising flattop high power laser pulse, with Gaussian intensity
distribution along its wavefront, causes single and double ionizations of
the gas through which it propagates. The foot of the pulse causes single
ionization of the gas and creates a sharp radial density profile resulting
in strong defocusing of the front part of the pulse. After a little while,
single state ionization saturates, creating a flat density profile in the
axial region and weakening the divergence of the pulse. As the intensity of
the pulse rises further, second state ionization occurs, causing strong
defocusing of the beam. Later in time when the second state ionization
saturates, the relativistic mass nonlinearity together with the electron
cavitation tends to focus the pulse. 相似文献
122.
Dileep Kumar Achutha Bharath Srinivasan Dharmappa Rekha N. Naveen Shivalingegowda Lokanath Neratur Krishnappagowda Ajay Kumar Kariyappa 《Research on Chemical Intermediates》2018,44(9):5635-5652
Research on Chemical Intermediates - The current study presents the synthesis of functionalized pyrazoles (18–29) through 3?+?2 annulation reaction of ethyl... 相似文献
123.
Viveka Shivapura Vasantha Gowda Dinesha Naveen Shivalingegowda Lokanath Neratur Krishnappagowda Nagaraja Gundibasappa Karikannar 《Research on Chemical Intermediates》2016,42(5):4497-4511
Research on Chemical Intermediates - The present research work has focused on combined experimental and theoretical studies of one of the biologically important pyrazole-4-carboxylic acid... 相似文献
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Naveen Yadav Aparna Tyagi Jabir Khan Chinmoy Kumar Hazra 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(64):e202201938
An unprecedented, Brookhart's acid-catalyzed temperature-switchable regioselective divergent approach for N-alkylation of arylamines and heterocyclic amines by utilising cyclopropylcarbinols is presented herein. The reaction offers N-alkylated cyclopropyl derivatives and homoallyl amines by employing 2.5 mol% catalyst loading at different temperatures in excellent regioselectivity and yields. This method has shown to be relevant with a wide range of cyclopropylcarbinols, including aliphatic ones. Several control experiments and spectroscopic studies have been performed to gain insight into the reaction mechanism. Further, the synthetic utility of the protocol has also been described. 相似文献
126.
Dr. Subhadeep Saha Dr. Yen-Ting Chen Dr. Sudhakar Ganta Markus Gilles Björn Holzapfel Dr. Pascal Lill Prof. Dr. Heinz Rehage Prof. Dr. Christos Gatsogiannis Prof. Dr. Guido H. Clever 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(5):e202103406
Metallo-supramolecular self-assembly has yielded a plethora of discrete nanosystems, many of which show competence in capturing guests and catalyzing chemical reactions. However, the potential of low-molecular bottom-up self-assemblies in the development of structured inorganic materials has rarely been methodically explored so far. Herein, we present a new type of metallo-supramolecular surfactant with the ability to stabilize non-aqueous emulsions for a significant period. The molecular design of the surfactant is based on a heteroleptic coordination cage ( CGA-3 ; CGA =Cage-based Gemini Amphiphile), assembled from two pairs of organic building blocks, grouped around two Pd(II) cations. Shape-complementarity between the differently functionalized components generates discrete amphiphiles with a tailor-made polarity profile, able to stabilize non-aqueous emulsions, such as hexadecane-in-DMSO. These emulsions were used as a medium for the synthesis of spherical metal oxide microcapsules (titanium oxide, zirconium oxide, and niobium oxide) from soluble, water-sensitive alkoxide precursors by allowing a controlled dosage of water to the liquid-liquid phase boundary. Synthesized materials were analyzed by a combination of electron microscopic techniques. In situ liquid cell transmission electron microscopy (LC-TEM) was utilized for the first time to visualize the dynamics of the emulsion-templated formation of hollow inorganic titanium oxide and zirconium oxide microspheres. 相似文献
127.
Today’s fertilizers rely heavily on mining phosphorus (P) rocks. These rocks are known to become exhausted in near future, and therefore effective P use is crucial to avoid food shortage. A substantial amount of P from fertilizers gets adsorbed onto soil minerals to become unavailable to plants. Understanding P interaction with these minerals would help efforts that improve P efficiency. To this end, we performed a molecular level analysis of the interaction of common organic P compounds (glycerolphosphate (GP) and inositol hexaphosphate (IHP)) with the abundant soil mineral (goethite) in presence of water. Molecular dynamics simulations are performed for goethite–IHP/GP–water complexes using the multiscale quantum mechanics/molecular mechanics method. Results show that GP forms monodentate (M) and bidentate mononuclear (B) motifs with B being more stable than M. IHP interacts through multiple phosphate groups with the 3M motif being most stable. The order of goethite–IHP/GP interaction energies is GP M < GP B < IHP M < IHP 3M. Water is important in these interactions as multiple proton transfers occur and hydrogen bonds are formed between goethite–IHP/GP complexes and water. We also present theoretically calculated infrared spectra which match reasonably well with frequencies reported in literature. 相似文献
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Ming-Fong Tsai Naveen Chilamkurti Ce-Kuen Shieh Alexey Vinel 《Mathematical and Computer Modelling》2011,53(11-12):2067-2077
Wireless transmission suffers from poor wireless channel conditions, such as high bit error rate and error bursts resulting from channel fading and radio interference. The MAC-level Forward Error Correction (MFEC) mechanism is proposed to solve these problems. The MFEC mechanism cannot only adaptively adjust Forward Error Correction (FEC) redundancy, depending on the network condition, but can also retransmit whole packets even if the error packet includes several bit errors. In this paper, an Adaptive MAC-level FEC (AMFEC) mechanism is proposed to improve wireless transmission quality. The AMFEC mechanism relies on the effective packet loss rate model to dynamically adjust MFEC redundancy in order to minimize error recovery overhead. The AMFEC mechanism will retransmit the error of sub-packets and increase FEC redundancy to reduce transmission redundancy. The AMFEC mechanism not only enhances the quality of wireless transmission but also reduces the overhead of retransmission. The experimental results show the AMFEC mechanism is better than conventional MFEC mechanisms. 相似文献