491 research outputs found
Optical and electrical properties of cobalt chloride doped polyvinyl alcohol polyvinylpyrrolidone blend
Films of cobalt chloride doped polyvinyl alc. - polyvinylpyrrolidone blend were prepd. by soln. casting method, in the doping range 0 wtâ% up to 42 wtâ%. These films were characterized by XRD, UV-âVisible spectrometry, FTIR, thermal anal. and elec. measurements. The films were semi-âcryst., with an av. crystallite size of few nanometers. The optical band gap due to indirect allowed transitions (in k-âspace) decreases from 4.6 eV for 1.5 wtâ% doping level to 4.0 eV at 35 wtâ% doping level. In addn., absorption peaks were obsd. at 2.3 eV, 3.0 eV and 1.7 eV, which indicate that doping results in formation of allowed energy bands within the forbidden gap. The Urbach energy, which measures the width of band tails within the forbidden gap, is found to significantly decrease with increase in doping level. DC elec. measurements show a good fit for 3-âD Variable Range Hopping model of cond. The temp. variation of elec. resistivity obeys the Arrhenius relation, from which the activation energy obtained is found to decrease from 4.1 eV for 1.5 wtâ% doping level to 3.1 eV for 19 wtâ% doping level. (c) 2014 American Institute of Physics
Microstructural studies on cobalt chloride doped PVA -âPVP blend
Soln. cast films of PVA (polyvinylalc.) and PVP (polyvinylpyrrolidone) blend, doped with cobalt chloride (CoCl2) in the concn. range (doping level) from 1 wtâ% up to 28 wtâ% were characterized, and the data collected was analyzed to yield information about the microstructure of these films. XRD, DTATGA, ATR-âFTIR, UV-âVis and DC elec. measurements were performed. Although un-âdoped PVA-âPVP blend (equal compn. of PVA and PVP by wt.) was amorphous, the CoCl2 doped films showed a semicryst. nature, the av. crystallite size increasing from 7.5 nm at 9 wtâ% doping level up to 19 nm at 26 wtâ% doping level. The FTIR and DTA-âTGA spectra were used to complement the information about microstructure of these samples provided by XRD, and also correlated with elec. and optical anal., the latter revealing a higher degree of structural order in CoCl2 doped PVA-âPVP blend films, on increased incorporation of cobalt chloride
Structural, AC and DC Electrical Transport Properties of Nano Titania - Polyacrylamide Composite Films
227-237The microstructural features as well as the AC and DC electrical properties of titanium dioxide (titania or TiO2)
nanoparticle (NP) filled polyacrylamide (PAM) composite films with filler level (FLs) Varied from 0.02 up to 19.5 Wt %
were experimentally studied . SEM images revealed that the composite films with FLs equal to 0.02 and 0.40 Wt %
(low FLs) showed homogeneous dispersion of spherical TiO2 NPs, whereas aggregation of the filler was observed at higher
FLs. The XRD patterns of these composite films revealed an increase in their amorphousness at low FLs. The activation
energy (Ea) determined from Arrhenius equation showed that the composite with FL equal to 0.40 Wt % exhibited the
lowest value of Ea (equal to 0.84 eV). Dielectric study revealed that the composite film with FL equal to 0.40 Wt %
exhibited the highest value bulk conductivity at room temperature (4.39Ă10-6S m-1 at 303 K). Hence, the composite sample
with FL 0.40Wt %, along with pure PAM, were subjected to a detailed dielectric study at various fixed temperatures ranging
from 303K up to 353K. The composite sample with FL 0.40 Wt % showed a maximum bulk conductivity of 1.12Ă10-4 S m-
1at temperature 353K, while it was 3.45Ă10-8 S m-1 for pure PAM at 303 K
Analysis of electrical measurements oncadmium chloridedoped PVA-PVP blend
Films of Poly(vinyl alcohol) (PVA) - Poly(vinyl pyrrolidone) (PVP) blend, doped withcadmium chloride (CdCl2) from 0.5 wt% up to 40 wt% andprepared by solution casting method,were studied using temperature dependent direct current (DC)electrical measurements. The DC electrical data were analyzed using Variable Range Hopping (VRH) modelin the temperature range varying from 303K up to 318K. The Mott parameters are determined. The study of time evolution of current passing through the sample, when a constant voltage is applied across it reveals that ions are the majority charge carriers, but the role of electrons in charge transport cannot be neglected. The activation energy (Ea) for mobility of charge carriers has been calculated from VRHand Arrhenius models
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Multidifferential study of identified charged hadron distributions in -tagged jets in proton-proton collisions at 13 TeV
Jet fragmentation functions are measured for the first time in proton-proton
collisions for charged pions, kaons, and protons within jets recoiling against
a boson. The charged-hadron distributions are studied longitudinally and
transversely to the jet direction for jets with transverse momentum 20 GeV and in the pseudorapidity range . The
data sample was collected with the LHCb experiment at a center-of-mass energy
of 13 TeV, corresponding to an integrated luminosity of 1.64 fb. Triple
differential distributions as a function of the hadron longitudinal momentum
fraction, hadron transverse momentum, and jet transverse momentum are also
measured for the first time. This helps constrain transverse-momentum-dependent
fragmentation functions. Differences in the shapes and magnitudes of the
measured distributions for the different hadron species provide insights into
the hadronization process for jets predominantly initiated by light quarks.Comment: All figures and tables, along with machine-readable versions and any
supplementary material and additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-013.html (LHCb
public pages
Study of the decay
The decay is studied
in proton-proton collisions at a center-of-mass energy of TeV
using data corresponding to an integrated luminosity of 5
collected by the LHCb experiment. In the system, the
state observed at the BaBar and Belle experiments is
resolved into two narrower states, and ,
whose masses and widths are measured to be where the first uncertainties are statistical and the second
systematic. The results are consistent with a previous LHCb measurement using a
prompt sample. Evidence of a new
state is found with a local significance of , whose mass and width
are measured to be and , respectively. In addition, evidence of a new decay mode
is found with a significance of
. The relative branching fraction of with respect to the
decay is measured to be , where the first
uncertainty is statistical, the second systematic and the third originates from
the branching fractions of charm hadron decays.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-028.html (LHCb
public pages
Measurement of the ratios of branching fractions and
The ratios of branching fractions
and are measured, assuming isospin symmetry, using a
sample of proton-proton collision data corresponding to 3.0 fb of
integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The
tau lepton is identified in the decay mode
. The measured values are
and
, where the first uncertainty is
statistical and the second is systematic. The correlation between these
measurements is . Results are consistent with the current average
of these quantities and are at a combined 1.9 standard deviations from the
predictions based on lepton flavor universality in the Standard Model.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-039.html (LHCb
public pages
Experimental study of PVA-PVP blend films doped with cadmium chloride monohydrate
The microstructure and properties of poly vinyl alcohol (PVA)-poly vinyl pyrrolidone (PVP) blend films doped with cadmium chloride monohydrate (CdCl2.H2O) have been experimentally studied using scanning electron microscope (SEM), atomic force microscope (AFM), X-ray diffraction (XRD), optical, electrical and differential scanning calorimetry (DSC) techniques in the doping range from 0.5 wt% up to 45 wt%. The SEM images reveal the formation of self-grown nanostructures in the form of nano-spheres and nano-rods in the doping range from 0.5 wt% up to 2.2 wt%. The XRD reveals formation of additional sharp peaks superposed on the amorphous pattern of PVA-PVP blend. This is attributed to the crystalline nature of dopant induced nanostructures. AFM scans show spike-like structures due to the dopant and also an increase in surface roughness. At 35 wt% of CdCl2, the surface of the film is smooth. The sample is found to be completely amorphous at 21.5 wt% and at higher doping levels, up to 45 wt%
Structural, AC and DC Electrical Transport Properties of Nano Titania - Polyacrylamide Composite Films
The microstructural features as well as the AC and DC electrical properties of titanium dioxide (titania or TiO2) nanoparticle (NP) filled polyacrylamide (PAM) composite films with filler level (FLs) Varied from 0.02 up to 19.5 Wt % were experimentally studied . SEM images revealed that the composite films with FLs equal to 0.02 and 0.40 Wt % (low FLs) showed homogeneous dispersion of spherical TiO2 NPs, whereas aggregation of the filler was observed at higher FLs. The XRD patterns of these composite films revealed an increase in their amorphousness at low FLs. The activation energy (Ea) determined from Arrhenius equation showed that the composite with FL equal to 0.40 Wt % exhibited thelowest value of Ea (equal to 0.84 eV). Dielectric study revealed that the composite film with FL equal to 0.40 Wt % exhibited the highest value bulk conductivity at room temperature (4.39Ă10-6S m-1 at 303 K). Hence, the composite sample with FL 0.40Wt %, along with pure PAM, were subjected to a detailed dielectric study at various fixed temperatures ranging from 303K up to 353K. The composite sample with FL 0.40 Wt % showed a maximum bulk conductivity of 1.12Ă10-4 S m- 1at temperature 353K, while it was 3.45Ă10-8 S m-1 for pure PAM at 303 K
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