1,269 research outputs found
On the spectrum of the AdS(5) x S-5 string at large lambda
archiveprefix: arXiv primaryclass: hep-th reportnumber: HU-EP-10-85 slaccitation: %%CITATION = ARXIV:1012.4471;%%archiveprefix: arXiv primaryclass: hep-th reportnumber: HU-EP-10-85 slaccitation: %%CITATION = ARXIV:1012.4471;%
Density Functional Theory screening of gas-treatment strategies for stabilization of high energy-density lithium metal anodes
To explore the potential of molecular gas treatment of freshly cut lithium
foils in non-electrolyte based passivation of high energy-density Li anodes,
density functional theory (DFT) has been used to study the decomposition of
molecular gases on metallic lithium surfaces. By combining DFT geometry
optimization and Molecular Dynamics, the effects of atmospheric (N2, O2, CO2)
and hazardous (F2, SO2) gas decomposition on Li(bcc) (100), (110), and (111)
surfaces on relative surface energies, work functions, and emerging electronic
and elastic properties are investigated. The simulations suggest that exposure
to different molecular gases can be used to induce and control reconstructions
of the metal Li surface and substantial changes (up to over 1 eV) in the work
function of the passivated system. Contrary to the other considered gases,
which form metallic adlayers, SO2 treatment emerges as the most effective in
creating an insulating passivation layer for dosages <= 1 mono-layer. The
substantial Li->adsorbate charge transfer and adlayer relaxation produce marked
elastic stiffening of the interface, with the smallest change shown by
nitrogen-treated adlayers
A note on the integral equation for the Wilson loop in N = 2 D=4 superconformal Yang-Mills theory
We propose an alternative method to study the saddle point equation in the
strong coupling limit for the Wilson loop in D=4 super
Yang-Mills with an SU(N) gauge group and 2N hypermultiplets. This method is
based on an approximation of the integral equation kernel which allows to solve
the simplified problem exactly. To determine the accuracy of this
approximation, we compare our results to those obtained recently by Passerini
and Zarembo. Although less precise, this simpler approach provides an explicit
expression for the density of eigenvalues that is used to derive the planar
free energy.Comment: 12 pages, v2: section 2.5 (Free Energy) amended and reference added,
to appear in J. Phys.
The Emergence of Aqueous Ammonium-Ion Batteries
Aqueous ammonium-ion (NH4+) batteries (AAIB) are a recently emerging technology that utilize the abundant electrode resources and the fast diffusion kinetics of NH to deliver an excellent rate performance at a low cost. Although significant progress has been made on AAIBs, the technology is still limited by various challenges. In this Minireview, the most recent advances are comprehensively summarized and discussed, including cathode and anode materials as well as the electrolytes. Finally, a perspective on possible solutions for the current limitations of AAIBs is provided
Tailoring the release of drugs having different water solubility by hybrid polymer-lipid microparticles with a biphasic structure
The aim of this study is to investigate the potential of hybrid polymer-lipid microparticles with a biphasic structure (b-MPs) as drug delivery system. Hybrid b-MPs of Compritol & REG;888 ATO as main lipid constituent of the shell and polyethylene glycol 400 as core material were produced by an innovative solvent-free approach based on spray congealing. To assess the suitability of hybrid b-MPs to encapsulate various types of APIs, three model drugs (fluconazole, tolbutamide and nimesulide) with extremely different water solubility were loaded into the polymeric core. The hybrid systems were characterized in terms of particle size, morphology and physical state. Various techniques (e.g. optical, Confocal Raman and Scanning Electron Microscopy) were used to investigate the influence of the drugs on different aspects of the b-MPs, including external and internal morphology, properties at the lipid/polymer interface and drug distribution. Hybrid b-MPs were suitable for the encapsulation of all drugs (encapsulation efficiency > 90 %) regardless the drug hydrophobic/hydrophilic properties. Finally, the drug release behaviors from hybrid b-MPs were studied and compared with traditional solid lipid MPs (consisting of only the lipid carrier). Due to the combination of lipid and polymeric materials, hybrid b-MPs showed a wide array of release profiles that depends on their composition, the type of loaded drug, the drug loading amount and location, providing a versatile platform and allowing the formulators to finely balance the release performance of drugs intended for oral administration. Overall, the study demonstrates that hybrid, solvent-free b-MPs produced by spray congealing are an extremely versatile delivery platform able to efficiently encapsulate and release very different types of drug compounds
Artificial Solid Electrolyte Interphases for Lithium Metal Electrodes by Wet Processing: The Role of Metal Salt Concentration and Solvent Choice
Wilson Loops in N=2 Super-Yang-Mills from Matrix Model
We compute the expectation value of the circular Wilson loop in N=2
supersymmetric Yang-Mills theory with N_f=2N hypermultiplets. Our results
indicate that the string tension in the dual string theory scales as the
logarithm of the 't Hooft coupling.Comment: 37 pages, 9 figures; v2: Numerical factors corrected, simple
derivation of Wilson loop and discussion of continuation to complex lambda
added; v3: instanton partition function re-analyzed in order to take into
account a contribution of the hypermultiplet
Localised degradation within sulfide-based all-solid-state electrodes visualised by Raman mapping
The distribution of degradation products, before and after cycling, within common sulfide-based solid electrolytes (β-LiPS, LiPSCl and LiGePS) was mapped using Raman microscopy. All composite electrodes displayed the appearance of side reaction products after the initial charge-discharge cycle, located at the site of a LiNiMnCoO particle
Scalable Synthesis of Microsized, Nanocrystalline ZnFeO-C Secondary Particles and Their Use in ZnFe O-C/LiNiMnO Lithium-Ion Full Cells
Conversion/alloying materials (CAMs) are a potential alternative to graphite as Liâion anodes, especially for highâpower performance. The so far most investigated CAM is carbonâcoated ZnFeO, which provides very high specific capacity of more than 900 mAhâg and good rate capability. Especially for the latter the optimal particle size is in the nanometer regime. However, this leads to limited electrode packing densities and safety issues in largeâscale handling and processing. Herein, a new synthesis route including three sprayâdrying steps that results in the formation of microsized, spherical secondary particles is reported. The resulting particles with sizes of 10â15 Îźm are composed of carbonâcoated ZnFeO nanocrystals with an average diameter of approximately 30â40 nm. The carbon coating ensures fast electron transport in the secondary particles and, thus, high rate capability of the resulting electrodes. Coupling partially prelithiated, carbonâcoated ZnFeO anodes with LiNiMnO cathodes results in cobaltâfree Liâion cells delivering a specific energy of up to 284 Whâkg (at 1âC rate) and power of 1105 Wâkgâ1 (at 3âC) with remarkable energy efficiency (>93â% at 1âC and 91.8â% at 3âC)
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