252 research outputs found
Magneto-transport and magnetic susceptibility of SmFeAsO1-xFx (x = 0.0 and 0.20)
Bulk polycrystalline samples, SmFeAsO and the iso-structural superconducting
SmFeAsO0.80F0.20 are explored through resistivity with temperature under
magnetic field {\rho}(T, H), AC and DC magnetization (M-T), and Specific heat
(Cp) measurements. The Resistivity measurement shows superconductivity for x =
0.20 sample with Tc(onset) ~ 51.7K. The upper critical field, [Hc2(0)] is
estimated ~3770kOe by Ginzburg-Landau (GL) theory. Broadening of
superconducting transition in magneto transport is studied through thermally
activated flux flow in applied field up to 130 kOe. The flux flow activation
energy (U/kB) is estimated ~1215K for 1kOe field. Magnetic measurements
exhibited bulk superconductivity with lower critical field (Hc1) of ~1.2kOe at
2K. In normal state, the paramagnetic nature of compound confirms no trace of
magnetic impurity which orders ferromagnetically. AC susceptibility
measurements have been carried out for SmFeAsO0.80F0.20 sample at various
amplitude and frequencies of applied AC drive field. The inter-granular
critical current density (Jc) is estimated. Specific heat [Cp(T)] measurement
showed an anomaly at around 140K due to the SDW ordering of Fe, followed by
another peak at 5K corresponding to the antiferromagnetic (AFM) ordering of
Sm+3 ions in SmFeAsO compound. Interestingly the change in entropy (marked by
the Cp transition height) at 5K for Sm+3 AFM ordering is heavily reduced in
case of superconducting SmFeAsO0.80F0.20 sample.Comment: 18 pages text + Figs: comments/suggestions welcome
([email protected]
An Ionic Molecular Glass as Electron Injection Layer for Efficient Polymer Light-Emitting Diode
An ionic molecular glass based on a dendronized monoammonium salt has been facilely synthesized and utilized as an interfacial electron-injection layer in a light-emitting diode (LED). The characterization of a yellow-green LED that involves an Al cathode and a thin layer of the new compound spin cast from a methanol solution has shown device performances comparable to those obtained with a Ba/Al cathode. Photovoltaic measurements under white light irradiation reveal that a thin layer of the new compound can significantly increase the built-in potential and thus facilitate electron injection from an Al cathode. Furthermore, it is interesting to observe that the new ionic salt could undergo reorganization on the emissive conjugated polymer layer, which leads to the formation of nearly uniform nanoaggregates
Measurement of the Atmospheric Muon Spectrum from 20 to 3000 GeV
The absolute muon flux between 20 GeV and 3000 GeV is measured with the L3
magnetic muon spectrometer for zenith angles ranging from 0 degree to 58
degree. Due to the large exposure of about 150 m2 sr d, and the excellent
momentum resolution of the L3 muon chambers, a precision of 2.3 % at 150 GeV in
the vertical direction is achieved.
The ratio of positive to negative muons is studied between 20 GeV and 500
GeV, and the average vertical muon charge ratio is found to be 1.285 +- 0.003
(stat.) +- 0.019 (syst.).Comment: Total 32 pages, 9Figure
Application of Improved Interferometry on Low SNR Data to Auto-pick First Arrivals
Three improvements are added to the traditional super-virtual refraction interferometry. Inverse correlation functions are used to enhance the quality of near-offset traces. Interferometry in common-receiver gathers increases the stacking fold. Wavelet shaping effectively suppresses spurious events. The improved interferometry increases the SNR of first arrivals on both synthetic data and real exploration data. We then add two methods to distinguish the spurious events and real events on super-virtual data by event consecutiveness and inexistence of spurious events in raw data. With improved interferometry and improved auto-picking process, we can accurately auto-pick first arrivals over an expanded aperture of low SNR data.EI
The study on bactericidal effect and ultrastructural alterations of chlorocresol nanoemulsion disinfectant against <i>Staphylococcus aureus</i>
Chlorocresol nanoemulsion disinfectant (CND) is an environmental disinfectant prepared with nanoemulsion as its drug carrier. This study aimed to investigate the bactericidal effect of CND on Staphylococcus aureus ( S. aureus) and its effect on bacterial ultrastructure. The neutralizing effect of CND against S. aureus was first screened by suspension quantitative evaluation experiment procedure of neutralizer. Disinfection performance was evaluated by the determination of Minimal Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC), quantitative bactericidal experiment, and comparative experiment of disinfection performance between 0.1% CND and 0.1% chlorocresol aqueous solution. Meanwhile, the effect of CND on the ultrastructure of S. aureus was investigated with scanning electron microscope (SEM) and transmission electron microscope (TEM) to preliminarily explore the bactericidal mechanism. The results showed that 3% Tween-80 in PBS could be screened as the neutralizer of CND against S. aureus. MIC and MBC were 100 ÎŒg/mL and 200 ÎŒg/mL, respectively. The bactericidal rates were all 100% when 0.06% and 0.08% disinfectant acted for 15 and 5 min, respectively. Furthermore, compared with 0.1% chlorocresol aqueous solution, the bactericidal effect of 0.1% CND was significantly enhanced (p<0.01). After treatment with CND for 10 min, SEM observation showed that the morphology of S. aureus cells were changed and the integrity destroyed. TEM observation showed that the cell shape changed, and the structures of the cell wall, cell membrane and cytoplasm were damaged in varying degrees. CND showed the strong bactericidal effect on S. aureus and could cause ultrastructure alterations of S. aureus
ÎŽ13C variation of C3 and C4 plants across an Asian monsoon rainfall gradient in arid northwestern China
Effects of stacking fault energy on the thermal stability and mechanical properties of nanostructured CuâAl alloys during thermal annealing
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