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951.
Dr. Bob C. Schroeder Dr. Zhe Li Michael A. Brady Dr. Gregório Couto Faria Dr. Raja Shahid Ashraf Dr. Christopher J. Takacs John S. Cowart Dr. Duc T. Duong Kar Ho Chiu Ching‐Hong Tan Dr. João T. Cabral Prof. Alberto Salleo Prof. Michael L. Chabinyc Prof. James R. Durrant Prof. Iain McCulloch 《Angewandte Chemie (International ed. in English)》2014,53(47):12870-12875
Cost‐effective, solution‐processable organic photovoltaics (OPV) present an interesting alternative to inorganic silicon‐based solar cells. However, one of the major remaining challenges of OPV devices is their lack of long‐term operational stability, especially at elevated temperatures. The synthesis of a fullerene dumbbell and its use as an additive in the active layer of a PCDTBT:PCBM‐based OPV device is reported. The addition of only 20 % of this novel fullerene not only leads to improved device efficiencies, but more importantly also to a dramatic increase in morphological stability under simulated operating conditions. Dynamic secondary ion mass spectrometry (DSIMS) and TEM are used, amongst other techniques, to elucidate the origins of the improved morphological stability. 相似文献
952.
V. Alagarsamy P. Parthiban V. Raja Solomon K. Dhanabal S. Murugesan G. Saravanan G. V. Anjana 《Journal of heterocyclic chemistry》2008,45(3):709-715
953.
Md Raja Sk Arya Bhattacharyya Shuvendu Saha Arpita Brahma Dr. Modhu Sudan Maji 《Angewandte Chemie (International ed. in English)》2023,62(30):e202305258
Annulative π-extension (APEX) reaction has become a powerful tool for the precise synthesis of well-defined polycyclic aromatic hydrocarbons (PAHs) such as nanographene, graphene, and other PAHs possessing unique structure. Herein, an APEX reaction has been realized at the masked bay-region for the efficient and rapid synthesis of valuable PAH, pyrene, bearing substitutions at the most challenging K-region. RhIII-catalyzed ketone-directed C−H activation at the peri-position of a naphthyl-derived ketone, alkyne-insertion, intramolecular nucleophilic attack at the carbonyl-group, dehydration, and aromatization steps occurred in one-pot to effectuate the protocol. Employing this strategy, a two-fold APEX reaction on enantiopure BINOL-derived ketones provided access to axially-chiral bipyrene derivatives. The detailed DFT study to support proposed mechanism, and synthesis of helical PAHs like dipyrenothiophene and dipyrenofuran are other highlights of the present study. 相似文献
954.
The relative cohomology Hdiff1(K(1|3), osp(2, 3);Dγ,µ(S1|3)) of the contact Lie superalgebra K(1|3) with coefficients in the space of differential operators Dγ,µ(S1|3) acting on tensor densities on S1|3, is calculated in N.Ben Fraj, I. Laraied, S. Omri (2013) and the generating 1-cocycles are expressed in terms of the infinitesimal super-Schwarzian derivative 1-cocycle s(Xf) = D1D2D3(f)α31/2, Xf ∈ K(1|3) which is invariant with respect to the conformal subsuperalgebra osp(2, 3) of K(1|3). 相似文献
955.
Effect of gamma irradiation on X‐ray absorption and photoelectron spectroscopy of Nd‐doped phosphate glass
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V. N. Rai Parasmani Rajput S. N. Jha D. Bhattacharyya B. N. Raja Shekhar U. P. Deshpande T. Shripathi 《Journal of synchrotron radiation》2016,23(6):1424-1432
X‐ray absorption near‐edge structure (XANES) and X‐ray photoelectron spectroscopy (XPS) of Nd‐doped phosphate glasses have been studied before and after gamma irradiation. The intensity and the location of the white line peak of the L3‐edge XANES of Nd are found to be dependent on the ratio O/Nd in the glass matrix. Gamma irradiation changes the elemental concentration of atoms in the glass matrix, which affects the peak intensity of the white line due to changes in the covalence of the chemical bonds with Nd atoms in the glass (structural changes). Sharpening of the Nd 3d5/2 peak profile in XPS spectra indicates a deficiency of oxygen in the glasses after gamma irradiation, which is supported by energy‐dispersive X‐ray spectroscopy measurements. The ratio of non‐bridging oxygen to total oxygen in the glass after gamma radiation has been found to be correlated to the concentration of defects in the glass samples, which are responsible for its radiation resistance as well as for its coloration. 相似文献
956.
Graphene-based electrochemical supercapacitors 总被引:9,自引:0,他引:9
S. R. C. Vivekchand Chandra Sekhar Rout K. S. Subrahmanyam A. Govindaraj C. N. R. Rao 《Journal of Chemical Sciences》2008,120(1):9-13
Graphenes prepared by three different methods have been investigated as electrode materials in electrochemical supercapacitors.
The samples prepared by exfoliation of graphitic oxide and by the transformation of nanodiamond exhibit high specific capacitance
in aq. H2SO4, the value reaching up to 117 F/g. By using an ionic liquid, the operating voltage has been extended to 3·5 V (instead of
1 V in the case of aq. H2SO4), the specific capacitance and energy density being 75 F/g and 31·9 Wh kg−1 respectively. This value of the energy density is one of the highest values reported to date. The performance characteristics
of the graphenes which are directly related to the quality, in terms of the number of layers and the surface area, are superior
to that of single-walled and multi-walled carbon nanotubes. 相似文献
957.
Rao NM Vijayalakshmi RP Reddy DR Reddy BK 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,69(2):688-691
(ZnS)1-x(MnTe)x luminescent powder samples with x=0.02, 0.05, 0.10, 0.15, 0.20 and 0.25 were prepared by solid-state reaction method. EPR spectra were recorded at room temperature (300K) in the frequency range 8.8-9.6GHz for samples of all compositions. The line width (DeltaH) and the number of spins increased with MnTe concentration. Room temperature dc magnetic susceptibility measurements were carried out using vibrating sample magnetometer. Susceptibility of the samples increased with MnTe content. 相似文献
958.
Kohr Mirela; Sekhar G. P. Raja; Blake John R. 《IMA Journal of Applied Mathematics》2008,73(2):374-392
The purpose of this paper is to obtain the Green's functionof the Brinkman equation in a 2D case of hydrodynamic anisotropywith respect to the permeability. The anisotropic nature ofthe permeability is assumed to be not space or time dependent.We use the method of Fourier transform which reduces the computationof the Green's function to the computation of the fundamentalsolution of a fourth-order partial differential equation. Thisresearch work has several applications in engineering and medicineto the motion of bodies in anisotropic porous media. 相似文献
959.
Manzoli M Shetti VN Blaine JA Zhu L Isrow D Yempally V Captain B Coluccia S Raja R Gianotti E 《Dalton transactions (Cambridge, England : 2003)》2012,41(3):982-989
Cluster-derived Ru(x)Pt(y)Sn(z) nanoparticles are active catalysts in the hydrogenation of nitrobenzene. The nature of the active sites has been elucidated by FTIR spectroscopy using CO and NO as probe molecules. A new metal carbonyl cluster precursor, Pt(2)Ru(2)(SnBu(t)(3))(2)(CO)(9)(μ-H)(2), has been synthesized to obtain a Ru(2)Pt(2)Sn(2)/SiO(2) catalyst, that displayed remarkably high levels of conversion and selectivities compared to other bi-and monometallic analogues. Spectroscopic comparisons with Ru(5)PtSn/SiO(2) indicate that both the nature and the stoichiometry of the metals play a key role in modulating the catalytic activities and selectivities. A multinuclear single-site containing Pt centers, which facilitate the hydrogen activation, coupled with a highly reactive Ru site, possibly involved in the nitrobenzene activation, can be hypothesized. The oxophilicity of tin helps with the anchoring of the nanoparticles, aids the dispersion of the other metals, and can play an important role in influencing the selectivity to aniline. 相似文献
960.
The seaweeds Dictyota dichotoma and Chaetomorpha linoides from the southeast coast of India were screened for anti-microfouling activity against biofilm bacteria, anti-macrofouling activity against brown mussels and feeding deterrence activity against the sea angel Monodactylus kottelati. The surface associated epiphytic bacteria were also isolated from seaweeds and screened for activity against biofilm bacteria. The acetone extracts showed a wide spectrum activity against biofilm bacteria and the algal metabolite was surface concentrated and non-polar in nature. The seaweeds also inhibited byssus production and attachment in brown mussels, and deterred feeding in the sea angel. The lower epiphytic bacterial number on the seaweed's surface compared to the surrounding seawater medium indicated selective inhibition or surface mediation. The epiphytic bacteria, which showed activity against biofilm bacteria, might also possibly play a role in seaweed defence strategies. The 50% deterrence of feeding activity at lower concentrations was not proportionate to the 100% inhibition concentration, which could be attributed to the adaptability of the fishes, an indication that the active substances are inhibitory in nature. This was further substantiated with the 100% recovery of mussels in a toxicity assay and the lower EC(50) values than LC(50) values in the mussel bioassay. The study indicates that the metabolites of both seaweeds have ecological significance and could possibly play a multifunctional role. 相似文献