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991.
Conversion-type transition metal fluoride cathodes offer a 200%–300% higher theoretical energy density limit than state-of-the-art intercalation cathodes. Recent publications have reshaped our understanding of the reaction mechanism in these materials. Herein, we review recent reports highlighting how active material dissolution, particle fusing, electrolyte consumption, and the resultant capacity fade can be mitigated by rational electrolyte design. Recent work has established the possibility of high discharge rate in transition metal fluorides at significant active material mass fraction; we examine the relationship between rate capability and active material fraction. Tuning transition metal fluoride chemistry via cation and anion substitution has demonstrated the potential to improve its electrochemical properties. A brief technoeconomic analysis is presented to highlight the practical advantages of different transition metal chemistries. 相似文献
992.
Epstein SA Shemesh D Tran VT Nizkorodov SA Gerber RB 《The journal of physical chemistry. A》2012,116(24):6068-6077
Methyl peroxide (CH(3)OOH) is commonly found in atmospheric waters and ices in significant concentrations. It is the simplest organic peroxide and an important precursor to hydroxyl radical. Many studies have examined the photochemical behavior of gaseous CH(3)OOH; however, the photochemistry of liquid and frozen water solutions is poorly understood. We present a series of experiments and theoretical calculations designed to elucidate the photochemical behavior of CH(3)OOH dissolved in liquid water and ice over a range of temperatures. The molar extinction coefficients of aqueous CH(3)OOH are different from the gas phase, and they do not change upon freezing. Between -12 and 43 °C, the quantum yield of CH(3)OOH photolysis is described by the following equation: Φ(T) = exp((-2175 ± 448)1/T) + 7.66 ± 1.56). We use on-the-fly ab initio molecular dynamics simulations to model structures and absorption spectra of a bare CH(3)OOH molecule and a CH(3)OOH molecule immersed inside 20 water molecules at 50, 200, and 220 K. The simulations predict large sensitivity in the absorption spectrum of CH(3)OOH to temperature, with the spectrum narrowing and shifting to the blue under cryogenic conditions because of constrained dihedral motion around the O-O bond. The shift in the absorption spectrum is not observed in the experiment when the CH(3)OOH solution is frozen suggesting that CH(3)OOH remains in a liquid layer between the ice grains. Using the extinction coefficients and photolysis quantum yields obtained in this work, we show that under conditions with low temperatures, in the presence of clouds with a high liquid-water content and large solar zenith angles, the loss of CH(3)OOH by aqueous photolysis is responsible for up to 20% of the total loss of CH(3)OOH due to photolysis. Gas phase photolysis of CH(3)OOH dominates under all other conditions. 相似文献
993.
Magdalena Gra?ulAleksander Kufelnicki Magdalena WozniczkaIngo-Peter Lorenz Peter MayerAndrzej Jó?wiak Malgorzata CzyzElzbieta Budzisz 《Polyhedron》2012,31(1):150-158
The chromone derivative 5-amino-8-methyl-4H-benzopyran-4-one (ligand) (1) has been used to obtain a series of Cu(II) complexes 2-4 as potential anticancer compounds. The molecular structures of ligand 1 and its Cu(II) complex 3 have been determined by X-ray crystallography. The cytotoxicity of all obtained compounds has been evaluated on melanoma A375 cell line. The ability of compounds 1-4 to take part in redox reactions and their antioxidant activity have been studied. 相似文献
994.
Linnebacher M Lorenz P Koy C Jahnke A Born N Steinbeck F Wollbold J Latzkow T Thiesen HJ Glocker MO 《Analytical and bioanalytical chemistry》2012,403(1):227-238
Patient-specific sequential epitopes were identified by peptide chip analysis using 15mer peptides immobilized on glass slides
that covered the topoisomerase IIa protein with a frameshift of five amino acids. Binding specificities of serum antibodies
against sequential epitopes were confirmed as being mono-specific by peptide chip re-analysis of epitope-affinity-purified
antibody pools. These results demonstrate that serum samples from colon carcinoma patients contain antibodies against sequential
epitopes from the topoisomerase IIa antigen. Interactions of patients’ antibodies with sequential epitopes displayed by peptides
on glass surfaces may thus mirror disease-specific immune situations. Consequently, these data suggest epitope–antibody reactivities
on peptide chips as potential diagnostic readouts of individual immune response characteristics, especially because monospecific
antibodies can be interrogated. Subsequently, the clonality of the antibodies present in the mono-specific antibody pools
was characterized by 2D gel electrophoresis. This analysis suggested that the affinity-purified antibodies were oligoclonal.
Similarly to large-scale screening approaches for specific antigen–antibody interactions in order to improve disease diagnostic,
we suggest that “protein-wide” screening for specific epitope–paratope interactions may help to develop novel assays for monitoring
of personalized therapies, since individual properties of antigen–antibody interactions remain distinguishable. 相似文献
995.
Let R ? G denote a crossed product of the finite group G over the ring R and let V be an R ? G-module. Maschke's theorem states that if 1/∣G∣ ε R and if V is completely reducible as an R-module, then V is also completely reducible as an R ? G -module. In this paper, we obtain two applications of this theorem, both under the assumption that R is semiprime with no ∣G∣ -torsion. The first concerns group actions and here we show that if G acts on R and if I is an essential right ideal of the fixed ring RG , then IR is essential in Rs. This result, in turn, simplifies a number of proofs already in the literature. The second application here is a short proof of a theorem of Fisher and Montgomery which asserts that the crossed product R ? G is semiprime. 相似文献
996.
K. P. O'Donnell M. Auf der Maur A. Di Carlo K. Lorenz the SORBET consortium 《固体物理学:研究快报》2012,6(2):49-52
The design strategy presently employed to obtain ‘white’ light from semiconductors combines the emission of an InGaN blue or UV light‐emitting diode (LED) with that of one or more yellow‐orange phosphors. While commercially successful, this approach achieves good colour rendering only by increasing the number and spectral range of the phosphors used; compared to the alternative of combining ‘true’ red, green and blue (RGB) sources, it is intrinsically inefficient. The two major roadblocks to the RGB approach are 1. the green gap in the internal quantum efficiency (IQE) of LEDs; 2. the diode droop in the efficiency of LEDs at higher current densities. The physical origin of these effects, in the case of III‐nitrides, is generally thought to be a combination of Quantum Confined Stark Effect (QCSE) and Auger Effect (AE). These effects respectively reduce the electron–hole wave‐ function overlap of In‐rich InGaN quantum wells (QW), and provide a non‐radiative shunt for electron–hole recombination, particularly at higher excitation densities. SORBET, a novel band gap engineering strategy based upon quantum well intermixing (QWIM), offers solutions to both of the roadblocks mentioned above. In this introduction to SORBET, its great potential is tested and confirmed by the results of simulations of green InGaN diodes performed using the TiberCAD device modelling suite, which calculates the macroscopic properties of real‐world optoelectronic and electronic devices in a multiscale formalism. An alternative approach to the realisation of RGB GaN‐based LEDs through doping of an active layer by rare earth (RE) ions will also be briefly described. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
997.
Simultaneous time and frequency detection in off‐resonant femtosecond degenerate four‐wave mixing (fs‐DFWM) experiments displays spectral features that are covered in standard, nondispersed, frequency‐integrated measurements. The application of laser fields with finite bandwidths, narrower than or comparable to the rotational Raman bands, affects the observed coherent signals. Information available from such experiments is split between the time and frequency domains and an improved measurement necessitates a combined detection. Rotational recurrences of oxygen (O2), measured by dispersed fs‐DFWM at room temperature, exhibit spectral characteristics, using 800‐nm laser pulses with ∼100 fs duration. Analysis of the detected signals in both dimensions incorporating temporal and spectral trends can assist in the extraction and interpretation of chemicophysical quantities from the experiment. The dispersed recurrent signals are in accordance with simulations. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
998.
Abstract The cubic to orthorhombic transition in PbSe is investigated by electrical resistivity measurements up to 7 GPa and for temperatures between 20 °C and 300 °C. The phase diagram is constructed and the kinetics of the transition is discussed. 相似文献
999.
Reflection approach for the analytical description of light ion implantation into bilayer structures
Abstract One of the main problems while developing analytical multilayer models for ion implantation is how to make them ‘physical'. Satisfactory agreement between results obtained with existing multilayer models and the Monte Carlo prediction cannot always be expected, since mostly none of the important physical effects is accounted for. Extensive Monte Carlo study has been performed in order to extract some guiding principles for the construction of a more physically based multilayer model. Ion reflection accross the interfaces has a very strong impact on the final shape of a multilayer profile. First attempts to include this phenomenon in a multilayer model have been made. In this paper, a simple approach for light ion reflection at an interface is presented and the incorporation into a multilayer model is discussed. 相似文献
1000.
Stochastic ordinary differential equations are investigated for which the coefficients depend on nonlocal properties of the current random variable in the sample space such as the expected value or the second moment. The approach here covers a broad class of functional dependence of the right-hand side on the current random state and is not restricted to pathwise relations. Existence and uniqueness of solutions is obtained as a limiting process by freezing the coefficients over short time intervals and applying existence and uniqueness results and appropriate estimates for stochastic ordinary differential equations. 相似文献