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63.
Miss Durga 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1959,10(5):502-508
Zusammenfassung In dieser Arbeit wird der unterschiedliche Widerstand an einem Kreiszylinder berechnet, der in einem steten Strom angebracht ist und von einer Anzahl von Wirbelbewegungen in zwei Reihen begleitet ist. 相似文献
64.
Scattering measurements on individual tracks and relative scattering measurements on pairs of tracks have been made in two stacks exposed to 6·2 and 5·7 BeV protons respectively from the Berkeley Bevatron. Spurious scattering was determined in these two stacks for cell lengths ranging from 1 mm. to 8 mm. In one stack the magnitude of spurious scattering was very low while in the other it was fairly high. Our results indicate that:
- (a)Spurious scattering varies with cell lengtht, as tx, wherex is about 0·8 fort = 1 mm. to 3 mm. and about 0·5 fort = 3 mm. to 8 mm. 相似文献
65.
K. Kanaka Durga 《International Journal of Non》2004,39(2):233-245
Full approximate storage (FAS) multigrid algorithm is the most commonly used multigrid algorithm for non-linear equations. The algorithm initially developed for steady-state equations was later extended to obtain steady-state solutions employing unsteady equations. In extending the FAS algorithm for the steady-state non-linear equations to unsteady non-linear equations, the FAS algorithm does not to take into account that the governing equations are typically linearized in time before they are solved. Thus, there is a scope to develop a new multigrid algorithm to apply the multigrid technique to the equations linearized in time. In the present work, such an algorithm is developed exploring this possibility and is implemented for two-dimensional incompressible and compressible flows coupled with explicit time marching procedures. The results of the new algorithm compare favourably with those of the FAS multigrid method and single grid. 相似文献
66.
Sol-gel based alumina powders with catalytic applications 总被引:1,自引:0,他引:1
Maria Cri?an Maria ZaharescuValluri Durga Kumari Machiraju SubrahmanyamDorel Cri?an Nicolae Dr?ganM?lina R?ileanu Mihaela JitianuAdriana Rusu Gullapelli SadanandamJakkidi Krishna Reddy 《Applied Surface Science》2011,258(1):448-455
The sol-gel process provides a new approach to the preparation of oxide materials and offers many advantages for making catalysts. Since homogeneous mixing can be achieved at the molecular scale, the chemical reactivity of the oxide surface can be greatly enhanced; thus powders with high surface area and optimized pore size distribution can be obtained at low temperatures. In the present work NiO/Al2O3 sol-gel catalysts were obtained by simultaneous gelation of aluminium isopropoxide and nickel nitrate. A comparative study with pure sol-gel alumina was also realized. By physical-structural studies the changes induced by the introduction of the Ni precursor, before and after aluminium alkoxide hydrolysis were highlighted. The introduction of Ni at the beginning of the reaction favors γ-Al2O3 crystallization. When Ni is added at the end of reaction, it delays the alumina crystallization and induces the disorder of the lattice. The obtained Ni doped sol-gel derived alumina has been used as catalyst in the finished form for glycerol reforming to generate H2 for fuel cell applications. Some evaluation results of Ni-doped alumina combined with TiO2 in photocatalytic glycerol reforming reaction have been included. 相似文献
67.
Karteek S. Durga Reddy A. Gopi Tej M. Bhuvan Rao M. V. Basaveswara 《Russian Journal of Organic Chemistry》2021,57(2):272-282
Russian Journal of Organic Chemistry - A new series of fused tricyclic coumarin derivatives were designed, synthesized by a simple and convenient method, starting from 4-hydroxycoumarin and... 相似文献
68.
Dr. Khadanand KC Dr. Toby Woods Dr. Lisa Olshansky 《Angewandte Chemie (International ed. in English)》2023,62(45):e202311790
Mononuclear monodioxolene valence tautomeric (VT) cobalt complexes typically exist in their low spin (l.s.) CoIII(cat2−) and high spin (h.s.) CoII(sq⋅−) forms (cat2−=catecholato, and sq⋅−=seminquinonato forms of 3,5−di−tBu-1,2-dioxolene), which reversibly interconvert via temperature-dependent intramolecular electron transfer. Typically, the remaining four coordination sites on cobalt are supported by a tetradentate ligand whose properties influence the temperature at which VT occurs. We report that replacing one chelating pyridyl arm of tris(2-pyridylmethyl)amine (tpa) with a weaker field ortho-anisole moiety facilitates access to a third magnetic state, and examine a series of related complexes. Variable temperature crystallographic, magnetic, calorimetric, and spectroscopic studies support that this third state is consistent with l.s. CoII(sq⋅−). Thus, our ligand modifications not only provide access to the VT transition from l.s. CoIII(cat2−) to l.s. CoII(sq⋅−), but at higher temperatures, the complex undergoes spin crossover from l.s. CoII(sq⋅−) to h.s. CoII(sq⋅−), representing the first example of two-step magnetic switching in a mononuclear monodioxolene cobalt complex. We hypothesize that ligand dynamicity may facilitate access to the rarely observed l.s. CoII(sq⋅−) intermediate state, suggesting a new design criterion in the development of stimulus-responsive multi-state molecular switches. 相似文献
69.
Kristian J. Chambers Patthadon Sanghong Daniel Carter Martos Dr. Giorgia Casoni Dr. Rory C. Mykura Dr. Durga Prasad Hari Dr. Adam Noble Prof. Varinder K. Aggarwal 《Angewandte Chemie (International ed. in English)》2023,62(50):e202312054
Enones are widely utilized linchpin functional groups in chemical synthesis and molecular biology. We herein report the direct conversion of boronic esters into enones using commercially available methoxyallene as a three-carbon building block. Following boronate complex formation by reaction of the boronic ester with lithiated-methoxyallene, protonation triggers a stereospecific 1,2-migration before oxidation generates the enone. The protocol shows broad substrate scope and complete enantiospecificity is observed with chiral migrating groups. In addition, various electrophiles could be used to induce 1,2-migration and give a much broader range of α-functionalized enones. Finally, the methodology was applied to a 14-step synthesis of the enone-containing polyketide 10-deoxymethynolide. 相似文献
70.
Charge Separation in Graphene‐Decorated Multimodular Tris(pyrene)–Subphthalocyanine–Fullerene Donor–Acceptor Hybrids 下载免费PDF全文
Chandra B. KC Gary N. Lim Prof. Dr. Francis D'Souza 《Angewandte Chemie (International ed. in English)》2015,54(17):5088-5092
A new approach to probe the effect of graphene on photochemical charge separation in donor–acceptor conjugates is devised. For this, multimodular donor–acceptor conjugates, composed of three molecules of pyrene, a subphthalocyanine, and a fullerene C60 ((Pyr)3SubPc‐C60), have been synthesized and characterized. These systems were hybridized on few‐layer graphene through π–π stacking interactions of the three pyrene moieties. The hybrids were characterized using Raman, HRTEM, and spectroscopic and electrochemical techniques. The energy levels of the donor–acceptor conjugates were fine‐tuned upon interaction with graphene and photoinduced charge separation in the absence and presence of graphene was studied by femtosecond transient absorption spectroscopy. Accelerated charge separation and recombination was detected in these graphene‐decorated conjugates suggesting that they could be used as materials for fast‐responding optoelectronic devices and in light energy harvesting applications. 相似文献