The effect of preliminary weak illumination at elevated temperatures on the photoelectric properties of undoped α-Si:H films is investigated. It is found that the dark conductivity and ...photoconductivity of films increases with the preliminary-illumination intensity, and the parameter γ determining the dependence of the photoconductivity on the illumination intensity decreases due to an increasing fraction of the bimolecular recombination of electrons at energy levels of the tail of the density of states of the conduction band. It is assumed that this effect may be induced by the presence of an uncontrolled oxygen impurity and an increase in the concentration of electrically active oxygen as a result of preliminary illumination of the films at elevated temperatures.
Z
boson peak tag-n-probe method was widely used for estimation of electron-to-photon misidentification rate for photon-oriented studies in Run I and in early Run II
pp
-collisions data. The increased ...luminosity and energy of collisions in Run II requires an improvement of the existing method, especially it is necessary for a description of underlying background spectra in the
Z
boson mass region of tag-n-probe mass distribution. This study presents the improved ways of tag-n-probe mass spectra fit in order to estimate a pure number of tag-n-probe events originating from the
Z
boson. Two approaches are considered. The first fit, with the exponential polynomial functions, does not include the
Z
peak itself. And the second one includes the
Z
peak, which is described by a Voigtian function. Comparison of
misidentification rate estimation with two approaches is presented. The study is done for conditions of ATLAS experiment during Run II at LHC and photon selection used in
measurements.
Redox potentials of photosensitive cyclometalated RuII derivatives of 2-phenylpyridine or 2-(4-tolyl)pyridine are controllably decreased by up to 0.8 V within several minutes. This is achieved by ...irradiation of the ruthena(II)cycles cis-Ru(o-X-2-py)(LL)(MeCN)2PF6 (2, X = C6H4 (a) or 4-MeC6H3 (b), LL = 1,10-phenanthroline or 2,2‘-bipyridine). The cis geometry of the MeCN ligands has been confirmed by the X-ray structural studies. The σ-bound sp2 carbon of the metalated ring is trans to LL nitrogen. Complexes 2 are made from Ru(o-X-2-py)(MeCN)4PF6 (1) and LL. This “trivial” ligand substitution is unusual because 1a reacts readily with phen in MeCN as solvent to give cis-Ru(o-C6H4-2-py)(phen)(MeCN)2PF6 (2c) in a 83% yield, but bpy does not afford the bpy-containing 2 under the same conditions. cis-Ru(o-C6H4-2-py)(bpy)(MeCN)2PF6 (2e) has been prepared in CH2Cl2 (74%). Studies of complexes 2c,e by cyclic voltammetry in MeOH in the dark reveal RuII/III quasy-reversible redox features at 573 and 578 mV (vs Ag/AgCl), respectively. A minute irradiation 2c and 2e converts them into new species with redox potentials of −230 and 270 mV, respectively. An exceptional potential drop for 2c is accounted for in terms of a photosubstitution of both MeCN ligands by methanol. ESR, 1H NMR, and UV−vis data indicate that the primary product of photolysis of 2c is an octahedral monomeric low-spin (S = 1/2) RuIII species, presumably cis-RuIII(o-C6H4-2-py)(phen)(MeOH)22+. The primary photoproduct of bpy complex 2e is cis-RuII(o-C6H4-2-py)(bpy)(MeCN)(MeOH)+, and this accounts for a lower decrease in the redox potential. Irradiation of 2c in the presence of added chloride affords (phen)(o-C6H4-2-py)ClRuIIIORuIVCl(o-C6H4-2-py)(phen)PF6, a first μ-oxo-bridged mixed valent dimer with a cyclometalated unit. The structure of the dimer has been established by X-ray crystallography.
The article considers the earthquake of April 5, 2017 with
M
W
GCMT
= 6.0 near the Turkmen–Iranian border, northeast of the Iranian village of Sefid Sang. During the entire seismic history of the ...region, this was the strongest seismic event within a 45 km radius of the epicenter. The earthquake caused widespread destruction in four villages; two people died and 100 were injured. The shaking was felt in population centers in Iran, Turkmenistan, and other countries. According to the compiled isoseist map, the northwestern orientation of isolines of equal intensity, coinciding with the strike of the nearest faults, and strong damping of the shaking intensity across tectonic structures were established. The macroseismic field equation has been established, which is close to the Blake–Shebalin equation with average world coefficients. According to both equations, the shaking intensity at the epicenter is estimated as
I
0
= 8. The northwestern (southeastern) orientation of the aftershock cluster and their southeast migration were revealed, which made it possible to choose the nodal plane of the focal mechanism with a similar strike as the active one. The fault plane parameters, length
L
= 30 km and width
W
= 12 km, have been estimated for the area of the highest aftershock density. The law of the decrease in the number of aftershocks with time has been established, which indicates rapid decay of the aftershock process.
The presence of “living” macroradicals in the volume of a polymer–monomer particle may be one of the factors responsible for the loss of the aggregative stability of latexes. If the adsorption ...protection of a polymer–monomer particle is insufficient, high content of “living” macroradicals leads to gelation in the latex in the course of storage. Correlation between the latex life time, hydration of nonionic surfactant molecules in the adsorption layer of a polymer–monomer particle, and extent of the action of the macroradicals was determined. Naphthalenesulfonic dispersing agents enhance the stability of latex systems in the step of polymerization and distillation of the monomers owing to a decrease in the critical micelle concentration of the emulsifier, to extension of the micellar period of the polymerization, to an increase in the degree of saturation of polymer–monomer particles, and to an increase in the probability of macroradical recombination in the volume of a polymer–monomer particle. With an increase in the degree of polycondensation of naphthalene-containing dispersing agents, their surface activity increases, whereas the ability to support the aggregative stability of latexes decreases.
Run2 sensitivity to anomalous quartic gauge couplings was estimated for ATLAS experiment at LHC with increased energy of proton-proton collisions s=13 TeV and expected 40 fb−1 of integral luminosity. ...Simulation of Zγγ process with anomalous ZZγγ and Zγγγ couplings was performed using VBFNLO MC generator. Differential distributions on four-body invariant mass of final state particles was used for extraction of expected limits on Effective Field Theory parameters fT0/Λ4, fT5/Λ4, fT9/Λ4, fM2/Λ4, fM3/Λ4. Combined limits are obtained from two charged leptonic decay channels of Z boson (Zγγ → l+l−γγ, where l = e or µ). Unitarity of expected limits was studied using dipole form factor approach.
Significant progress was made in the past decade in understanding the mechanisms that regulate the circadian rhythms and, in particular, the sleep–wake cycle. In the light of new data, the regulation ...of the sleep–wake cycle is a multilevel process that involves various systems and functional clusters of the body to trigger and maintain wakefulness or slow-wave and REM sleep. The review summarizes information about the above mechanisms; bioenergetic processes in the brain; and the regulation of synaptic homeostasis, the immune system, glymphatic clearance, etc. Although a target of therapeutics in many diseases, sleep remains one of the main mysteries that the scientific community is facing.
Sensitivity to anomalous Z
Z
γγ and
Z
γγγ couplings in
Z
γγ production was probed for the ATLAS experiment at Large Hadron Collider.
Z
γγ process with anomalous couplings simulation in ppcollisions ...with √
s
= 13 TeV was performed using VBFNLO MC generator. The expected limits on the Effective Field Theory parameters
f
T
0
/Λ4,
f
T
5
/Λ4,
f
T
9
/Λ4,
f
M
2
/Λ4,
f
M
3
/Λ4 were extracted for 5 fb
−1
integral luminosity using the distribution on the invariant mass of
Z
γγ from the combination of charged leptonic decay channels of Z boson (
Z
γγ → μ
+
μ
−
γγ and
Z
γγ → e
+
e
−
γγ).
The kinetics of relaxation of the light-induced (at a temperature above 140°C) dark conductivity of undoped
a
-Si:H films is studied. The calculated time dependences of the relaxation rate of the ...dark conductivity are analyzed under the assumption that the thermal rates of the generation and relaxation of metastable defects formed by preliminary illumination are independent of illumination. It is shown that the features of the kinetics of the relaxation rates of dark conductivity under illumination are determined by the presence of light-induced processes of the relaxation and generation of slowly relaxing metastable defects whose energy levels are located in the upper half of the band gap.
The effect of weak illumination during the initial stage of relaxation of the dark metastable conductivity of an undoped
a
-Si:H film, photoinduced at
T
= 425 K, on the rate of its subsequent thermal ...relaxation is studied. It is found that the kinetics of relaxation upon illumination or in the absence of illumination is described by stretched exponents with the parameters τ
0
and β, which are smaller in the case of illumination. It is shown that a decrease in these parameters increases the rate of thermal relaxation of the dark conductivity of the film. Because the temperature and the illumination intensities at which the study is carried out are low, the changes in the relaxation rate of the metastable conductivity are unlikely associated with significant restructuring of the amorphous network. This may be due to changes in the system of hydrogen bonds, which can result, in particular, from the generation and relaxation of slow photoinduced defects under the influence of illumination.