Search for the tensor glueball Klempt, E.; Nikonov, K.V.; Sarantsev, A.V. ...
Physics letters. B,
07/2022, Letnik:
830
Journal Article
Recenzirano
Odprti dostop
The tensor glueball is searched for in BESIII data on radiative J/ψ decays into π0π0 and KsKs. The ππ invariant mass distribution exhibits an enhancement that can be described by a pole at ...(2210±60)−i(180±60)MeV or by three of ϕϕ resonances suggested a long time ago to be the trace of one, two or three glueballs. We speculate that several high-mass tensor mesons might have qq¯ and glueball components.
.
The isobar model EtaMAID has been updated with new and high precision data for
η
and
η
photoproduction on protons and neutrons from MAMI, ELSA, GRAAL and CLAS. The background is described in a ...recently developed Regge cut model, and for the resonance part the whole list of nucleon resonances has been investigated with 21
N
*
states contributing to
η
photoproduction and 12
N
*
states contributing to
η
photoproduction. A new approach is discussed to avoid double counting in the overlap region of Regge and resonances. A comparison is done among four newly updated partial waves analyses for observables and partial waves. Finally, the possibility of a narrow resonance near
W
=
1900
MeV is discussed, that would be able to explain unexpected energy and angular dependence of observables in
p
(
γ
,
η
)
p
near
η
threshold.
—
Using content analysis and the Python programming environment, we have found a number of general relationships determining the thermal properties of fluoride and modified fluoride glasses. Their ...compositions have been classified according to their glass transition temperature (
T
g
) and the difference between their crystallization onset temperature (
T
x
) and glass transition temperature:
T
x
–
T
g
. The use of Kauzmann’s rule for fluoride glasses, unmodified and modified with other halogens, has been shown to be more reliable if the
T
g
/
T
m
ratio is used, compared to the
T
g
/
T
l
ratio. We have qualitatively assessed how anion modification influences characteristic temperatures (glass transition temperature
T
g
, crystallization onset temperature
T
x
, crystallization peak temperature
T
c
, melting onset temperature
T
m
, and liquidus temperature
T
l
) and crystallization stability criteria (Hruby criterion
K
, Saad–Poulain criterion
S
, reduced thermal stability interval
H
, thermal stability interval
T
x
–
T
g
, and reduced glass transition temperatures
T
g
/
T
m
and
T
g
/
T
l
).
Study of the Viscosity of Arsenic Acid Solutions Fedorov, V. A.; Menshchikova, T. K.; Nikonov, K. S. ...
Theoretical foundations of chemical engineering,
10/2023, Letnik:
57, Številka:
5
Journal Article
Recenzirano
To optimize the processes of obtaining high-purity arsine and elemental arsenic by the electrochemical method, the dynamic viscosity is calculated and the kinematic viscosity is measured in solutions ...of arsenic acid formed by the electrolysis of a solution of hydrolytic sodium arsenite, the main product of the destruction of lewisite, in a temperature range of 20–80°C and a wide concentration range of 20–74 wt %.
Ceramic samples of Y
3
MgGa
3
SiO
12
, Y
3
MgGa
2
AlSiO
12
, and Y
3
MgGaAl
2
SiO
12
multicomponent garnets doped with 0.2 at % Cr
3+
have been obtained by high-temperature solid-state synthesis. In ...the luminescence spectra of the synthesized garnet samples, overlapping broadband luminescence is observed in the far red spectral region caused by the
4
T
2
→
4
A
2
transition in Cr
3+
ions, and a narrow band is observed in the range of 690–700 nm, corresponding to the zero-phonon line of the
2
Е →
4
A
2
transition in Cr
3+
. The narrow-band and broad-band parts of the spectra are attributed to radiation from two different types of chromium centers, which are in octahedral coordination with different distortion degrees and strength of the crystal field. This results from the presence of two ions at the octahedral position of these garnets, which differ significantly in crystal chemical properties, namely, Mg
2+
and Ga
3+
(Al
3+
). The studied phosphors, which have broadband luminescence in the phytoactive far red region of the spectrum, have the potential for use in greenhouse LED lamps.
A process for the growth of VSe
2
and VTe
2
single crystals using VCl
3
as a transport agent is proposed and experimentally demonstrated. X-ray diffractometry and Laue X-ray photography results ...indicate that the crystals thus grown are identical in properties to chalcogenide crystals grown using I
2
as a transport agent. The mechanism of chemical vapor transport is discussed and the process conditions are optimized.
Features of Methods to Produce High-Purity Arsenic Fedorov, V. A.; Menshchikova, T. K.; Nikonov, K. S. ...
Theoretical foundations of chemical engineering,
08/2023, Letnik:
57, Številka:
4
Journal Article
Recenzirano
This review surveys patent information and fundamental literature sources on the technological foundations of producing high-purity arsenic and its compounds in the leading countries: Russia (USSR), ...USA, Japan, Germany, and China. The 1960–1979 literature sources on the following issues are summarized:—recovery of elemental arsenic from various raw materials;—production of high-purity (99.99999 wt %) arsenic and its compounds;—devices and equipment for recovery and purification of elemental arsenic and arsenic-containing substances.
To study chemical transport and refine synthetic routes, single crystals of vanadium and zirconium diselenides were grown by the chemical transport reaction method using I
2
and Cl
2
as transporting ...agents. The thermodynamic parameters of chemical transport have been evaluated, and the mass transfer direction in a growth ampoule has been determined. The phase composition of the samples has been examined by X‑ray powder diffraction. Analysis of X-ray powder diffraction patterns of samples from the low- and high-temperature zones of the growth ampoule has confirmed the predictions based on thermodynamic calculations. With both transporting agents, ZrSe
2
transport occurs from the cold to the hot zone of the ampoule, while the direction of VSe
2
transport depends on the nature of the transporting agent. With I
2
as a transporting agent, transport occurs from the hot to the cold zone of the ampoule, while with Cl
2
, in the opposite mass transfer direction is observed. Microphotographs of the samples are consistent with thermodynamic and X‑ray diffraction data. The results can be used to optimize the technology of producing layered transition metal dichalcogenides.
—
Ceramic LiAl
5
O
8
lithium aluminate spinel materials doped with trivalent chromium ions have been prepared by high-temperature solid-state synthesis. The intensity, spectral shift, and width of ...two zero-phonon luminescence lines (
R
lines) due to transitions from the
2
E
excited state to the
4
A
2
ground state of Cr
3+
ions have been measured as functions of temperature in the range 80–295 K. Analysis of luminescence and luminescence excitation spectra of the ceramics points to severe local lattice distortion around the Cr
3+
ions, which shows up, in particular, as large inhomogeneous broadening of the zero-phonon Cr
3+
luminescence lines. The temperature dependences of the relative intensity, spectral shift, and width of the two zero-phonon lines can be sufficiently well described in terms of existing models for optical centers in crystals. The feasibility of using these temperature dependences for noncontact luminescence thermometry is assessed. Analysis of the data obtained in this study provides no way to uniquely identify the observed zero-phonon lines as due to transitions from two sublevels of the
2
E
state of a single type of chromium center (that is, as
R
1
and
R
2
lines) or transitions of two inequivalent chromium centers coupled by nonresonant energy transfer.
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