1,051 research outputs found
Classification of areas using pixel-by-pixel and sample classifiers
There are no author-identified significant results in this report
Reactions of (-)-sparteine with alkali metal HMDS complexes : conventional meets the unconventional
Conventional (-)-sparteine adducts of lithium and sodium 1,1,1,3,3,3-hexamethyldisilazide (HMDS) were prepared and characterised, along with an unexpected and unconventional hydroxyl-incorporated sodium sodiate, [(-)-sparteine·Na(-HMDS)Na·(-)-sparteine]+[Na4(-HMDS)4(OH)]--the complex anion of which is the first inverse crown ether anion
Ramanujan sums for signal processing of low frequency noise
An aperiodic (low frequency) spectrum may originate from the error term in
the mean value of an arithmetical function such as M\"obius function or
Mangoldt function, which are coding sequences for prime numbers. In the
discrete Fourier transform the analyzing wave is periodic and not well suited
to represent the low frequency regime. In place we introduce a new signal
processing tool based on the Ramanujan sums c_q(n), well adapted to the
analysis of arithmetical sequences with many resonances p/q. The sums are
quasi-periodic versus the time n of the resonance and aperiodic versus the
order q of the resonance. New results arise from the use of this
Ramanujan-Fourier transform (RFT) in the context of arithmetical and
experimental signalsComment: 11 pages in IOP style, 14 figures, 2 tables, 16 reference
Qualification Tests of 474 Photomultiplier Tubes for the Inner Detector of the Double Chooz Experiment
The hemispherical 10" photomultiplier tube (PMT) R7081 from Hamamatsu
Photonics K.K. (HPK) is used in various experiments in particle and
astroparticle physics. We describe the test and calibration of 474 PMTs for the
reactor antineutrino experiment Double Chooz. The unique test setup at
Max-Planck-Institut f\"ur Kernphysik Heidelberg (MPIK) allows one to calibrate
30 PMTs simultaneously and to characterize the single photo electron response,
transit time spread, linear behaviour and saturation effects, photon detection
efficiency and high voltage calibration
Qualification Tests of 474 Photomultiplier Tubes for the Inner Detector of the Double Chooz Experiment
The hemispherical 10" photomultiplier tube (PMT) R7081 from Hamamatsu
Photonics K.K. (HPK) is used in various experiments in particle and
astroparticle physics. We describe the test and calibration of 474 PMTs for the
reactor antineutrino experiment Double Chooz. The unique test setup at
Max-Planck-Institut f\"ur Kernphysik Heidelberg (MPIK) allows one to calibrate
30 PMTs simultaneously and to characterize the single photo electron response,
transit time spread, linear behaviour and saturation effects, photon detection
efficiency and high voltage calibration
Qualification Tests of 474 Photomultiplier Tubes for the Inner Detector of the Double Chooz Experiment
The hemispherical 10" photomultiplier tube (PMT) R7081 from Hamamatsu
Photonics K.K. (HPK) is used in various experiments in particle and
astroparticle physics. We describe the test and calibration of 474 PMTs for the
reactor antineutrino experiment Double Chooz. The unique test setup at
Max-Planck-Institut f\"ur Kernphysik Heidelberg (MPIK) allows one to calibrate
30 PMTs simultaneously and to characterize the single photo electron response,
transit time spread, linear behaviour and saturation effects, photon detection
efficiency and high voltage calibration
Mechanical Strength Degradation of Graphite Fiber Reinforced Thermoset Composites Due to Porosity
The mechanical strength of composite laminates is sensitive to the presence of porosity. Porosity in laminates is generally considered to be a random distribution of voids incurred during the manufacture process. Larger, interlaminar voids typically result from trapped air or moisture; smaller, intralaminar voids may occur between fibers due to improper wetting or the release of volatile gases during the cure cycle. Porosity has its greatest effects on matrix-dominated mechanical properties such as compressive strength, transverse tensile strength and interlaminar shear strength (ILSS). Judd and Wright [1] have surveyed the existing data and made an appraisal of the effects of voids on the mechanical properties of composites. In a study of porosity in filament wound/CVD carbon-carbon composite [2], the transverse tensile strength was found to decrease exponentially with increasing porosity and followed an empirical equation often attributed to Ryshkewitch [3] and Duckworth [4]: σ = σmaxeBP (1) where σmax is the strength at zero porosity, P is the volume fraction of porosity, and B (a negative number) is an empirical constant that depends on pore size, shape, and orientation. More recently Yoshida et. al
Lithium Salt Effects on Silicon Electrode Performance and Solid Electrolyte Interphase (SEI) Structure, Role of Solution Structure on SEI Formation
Silicon electrodes were cycled with electrolytes containing different salts to investigate the effect of salt on the electrochemical performance and SEI structure. Comparable capacity retention were observed for the 1.2 M LiPF6, LiTFSI and LiClO4 electrolytes in ethylene carbonate (EC):dimethyl carbonate (DEC), 1:1, but severe fading was observed for the 1.2 M LiBF4 electrolyte. The differential capacity plots and EIS analysis reveals that failure of the 1.2 M LiBF4 electrolyte is attributed to large surface resistance and increasing polarization upon cycling. However, when LiBF4 was added as an electrolyte additive (10% LiBF4 and 90% LiPF6), the capacity retention and Coulombic efficiency were improved. The SEI was analyzed by FTIR and XPS for each electrolyte. Both spectroscopic methods suggest that the main components of the SEI are lithium ethylene dicarbonate (LEDC) and Li2CO3 in the 1.2 M LiPF6, LiTFSI and LiClO4 electrolytes, while an inorganic-rich SEI, composed of LiF and borates, was generated for both the 1.2 M LiBF4 electrolyte and the 10% LiBF4 electrolyte. The chemical composition of the SEIs and corresponding electrochemical performance of the Si electrodes were strongly correlated with electrolyte solution structure
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Reply to Smith et al.: Social tipping dynamics in a world constrained by conflicting interests
[No abstract available
Capacity Fading Mechanisms of Silicon Nanoparticle Negative Electrodes for Lithium Ion Batteries
A thorough analysis of the evolution of the voltage profiles of silicon nanoparticle electrodes upon cycling has been conducted. The largest changes to the voltage profiles occur at the earlier stages (\u3e 0.16 V vs Li/Li+) of lithiation of the silicon nanoparticles. The changes in the voltage profiles suggest that the predominant failure mechanism of the silicon electrode is related to incomplete delithiation of the silicon electrode during cycling. The incomplete delithiation is attributed to resistance increases during delithiation, which are predominantly contact and solid electrolyte interface (SEI) resistance. The capacity retention can be significantly improved by lowering delithiation cutoff voltage or by introducing electrolyte additives, which generate a superior SEI. The improved capacity retention is attributed to the reduction of the contact and SEI resistance
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