777 research outputs found
Nucleon-nucleon interaction in the -matrix inverse scattering approach and few-nucleon systems
The nucleon-nucleon interaction is constructed by means of the -matrix
version of inverse scattering theory. Ambiguities of the interaction are
eliminated by postulating tridiagonal and quasi-tridiagonal forms of the
potential matrix in the oscillator basis in uncoupled and coupled waves,
respectively. The obtained interaction is very accurate in reproducing the
scattering data and deuteron properties. The interaction is used in the no-core
shell model calculations of H and He nuclei. The resulting binding
energies of H and He are very close to experimental values.Comment: Text is revised, new figures and references adde
The synthesis of benzo[4,5]thieno[2,3-f]isoindole-carboxylic acids by IMDAV reaction
We successfully managed to expand the described approach to benzothiophene derivatives. 3-(Benzo[b]thiophen-2-yl)allylanilines were made to react with maleic anhydrides, a number of benzo[4,5]thieno[2,3-f]isoindole-10-carboxylic acids were obtained in different yields.This work was supported by the Russian Foundation for Basic Research (project № 19-03-00807 A)
Broadband spectroscopy of astrophysical ice analogues: II. Optical constants of CO and CO ices in the terahertz and infrared ranges
Context: Broadband optical constants of astrophysical ice analogues in the
infrared (IR) and terahertz (THz) ranges are required for modeling the dust
continuum emission and radiative transfer in dense and cold regions, where
thick icy mantles are formed on the surface of dust grains. Aims: In this
paper, the THz time-domain spectroscopy (TDS) and the Fourier-transform IR
spectroscopy (FTIR) are combined to study optical constants of CO and CO
ices in the broad THz-IR spectral range. Methods: The measured ices are grown
at cryogenic temperatures by gas deposition on a cold Si window. A method to
quantify the broadband THz-IR optical constants of ices is developed based on
the direct reconstruction of the complex refractive index of ices in the THz
range from the TDS data, and the use of the Kramers-Kronig relation in the IR
range for the reconstruction from the FTIR data. Uncertainties of the
Kramers-Kronig relation are eliminated by merging the THz and IR spectra. The
reconstructed THz-IR response is then analyzed using classical models of
complex dielectric permittivity. Results: The complex refractive index of CO
and CO ices deposited at the temperature of K is obtained in the range
of 0.3--12.0 THz. Based on the measured dielectric constants, opacities of the
astrophysical dust with CO and CO icy mantles are computed. Conclusions:
The developed method can be used for a model-independent reconstruction of
optical constants of various astrophysical ice analogs in a broad THz-IR range.
Such data can provide important benchmarks to interpret the broadband
observations from the existing and future ground-based facilities and space
telescopes. The reported results will be useful to model sources that show a
drastic molecular freeze-out, such as central regions of prestellar cores and
mid-planes of protoplanetary disks, as well as CO and CO snow lines in
disks.Comment: Accepted for publication in A&A, 9 pages, 7 figure
Inverse scattering J-matrix approach to nucleon-nucleus scattering and the shell model
The -matrix inverse scattering approach can be used as an alternative to a
conventional -matrix in analyzing scattering phase shifts and extracting
resonance energies and widths from experimental data. A great advantage of the
-matrix is that it provides eigenstates directly related to the ones
obtained in the shell model in a given model space and with a given value of
the oscillator spacing . This relationship is of a particular
interest in the cases when a many-body system does not have a resonant state or
the resonance is broad and its energy can differ significantly from the shell
model eigenstate. We discuss the -matrix inverse scattering technique,
extend it for the case of charged colliding particles and apply it to the
analysis of and scattering. The results are compared with
the No-core Shell Model calculations of He and Li.Comment: Some text is added following suggestions of a journal refere
Rapid Ring-Opening Metathesis Polymerization of Monomers Obtained from Biomass-Derived Furfuryl Amines and Maleic Anhydride
Well-controlled and extremely rapid ring-opening metathesis polymerization of unusual oxanorbornene lactam esters by Grubbs third-generation catalyst is used to prepare a range of bio-based homo- and copolymers. Bio-derived oxanorbornene lactam monomers were prepared at room temperature from maleic anhydride and secondary furfuryl amines by using a 100 % atom economical, tandem Diels–Alder lactamization reaction, followed by esterification. Several of the resulting homo- and copolymers show good control over polymer molecular weight and have narrow molecular weight distributions
Phonon assisted resonant tunneling and its phonons control
© 2016, Pleiades Publishing, Inc.We observe a series of sharp resonant features in the tunneling differential conductance of InAs quantum dots. We found that dissipative quantum tunneling has a strong influence on the operation of nanodevices. Because of such tunneling the current–voltage characteristics of tunnel contact created between atomic force microscope tip and a surface of InAs/GaAs quantum dots display many interesting peaks. We found that the number, position, and heights of these peaks are associated with the phonon modes involved. To describe the found effect we use a quasi-classical approximation. There the tunneling current is related to a creation of a dilute instanton–anti-instanton gas. Our experimental data are well described with exactly solvable model where one charged particle is weakly interacting with two promoting phonon modes associated with external medium. We conclude that the characteristics of the tunnel nanoelectronic devices can thus be controlled by a proper choice of phonons existing in materials, which are involved
Phonon assisted resonant tunnelling and its phonons control
© 2016 Pleiades Publishing, Inc.We observe a series of sharp resonant features in the tunnelling differential conductance of InAs quantum dots. We found that dissipative quantum tunnelling has a strong influence on the operation of nano-devices. Because of such tunnelling the current-voltage characteristics of tunnel contact created between atomic force microscope tip and a surface of InAs/GaAs quantum dots display many interesting peaks. We found that the number, position, and heights of these peaks are associated with the phonon modes involved. To describe the found effect we use a quasi-classical approximation. There the tunnelling current is related to a creation of a dilute instanton-anti-instanton gas. Our experimental data are well described with exactly solvable model where one charged particle is weakly interacting with two promoting phonon modes associated with external medium. We conclude that the characteristics of the tunnel nanoelectronic devices can thus be controlled by a proper choice of phonons existing in materials, which are involved
Shrinking a large dataset to identify variables associated with increased risk of Plasmodium falciparum infection in Western Kenya
Large datasets are often not amenable to analysis using traditional single-step approaches. Here, our general objective was to apply imputation techniques, principal component analysis (PCA), elastic net and generalized linear models to a large dataset in a systematic approach to extract the most meaningful predictors for a health outcome. We extracted predictors for Plasmodium falciparum infection, from a large covariate dataset while facing limited numbers of observations, using data from the People, Animals, and their Zoonoses (PAZ) project to demonstrate these techniques: data collected from 415 homesteads in western Kenya, contained over 1500 variables that describe the health, environment, and social factors of the humans, livestock, and the homesteads in which they reside. The wide, sparse dataset was simplified to 42 predictors of P. falciparum malaria infection and wealth rankings were produced for all homesteads. The 42 predictors make biological sense and are supported by previous studies. This systematic data-mining approach we used would make many large datasets more manageable and informative for decision-making processes and health policy prioritization
Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC
Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ γ, H → Z Z∗ →4l and H →W W∗ →lνlν. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson
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