54 research outputs found
Double-loop hysteresis of multisite dilute Sr(YDy)O single crystal Kramers paramagnets: electron-phonon interaction, quantum tunneling and cross-relaxation
Experimental and theoretical studies of the dynamic magnetization in swept
magnetic fields of the orthorhombic SrYO single-crystals doped with the
Dy Kramers ions (0.01 and 0.5 at.%) with natural abundances of even and
odd Dy isotopes are presented. Impurity ions substitute for Y ions at
two nonequivalent crystallographic sites with the same local symmetry but
strongly different crystal fields. Well pronounced double-loop hysteresis is
observed at temperatures 2, 4, 5 and 6 K for sweeping rates of 5 and 1 mT/s.
The microscopic model of spectral, magnetic and kinetic properties of Dy
ions is developed based on the results of EPR, site selective optical spectra
and magnetic relaxation measurements. The derived approach to the dynamic
magnetization in the sweeping field based on the numerical solution of
generalized master equations with time-dependent transition probabilities
induced by the electron-phonon interaction, quantum tunneling and
cross-relaxation allowed us to reproduce successfully the evolution of the
hysteresis loop shape with temperature, sweeping rate and concentration of
paramagnetic ions.Comment: 11 pages, 6 figures, 2 tables, 52 reference
Broadband optical properties of monolayer and bulk MoS2
Layered semiconductors such as transition metal dichalcogenides (TMDs) offer endless possibilities for designing modern photonic and optoelectronic components. However, their optical engineering is still a challenging task owing to multiple obstacles, including the absence of a rapid, contactless, and the reliable method to obtain their dielectric function as well as to evaluate in situ the changes in optical constants and exciton binding energies. Here, we present an advanced approach based on ellipsometry measurements for retrieval of dielectric functions and the excitonic properties of both monolayer and bulk TMDs. Using this method, we conduct a detailed study of monolayer MoS2 and its bulk crystal in the broad spectral range (290β3300 nm). In the near- and mid-infrared ranges, both configurations appear to have no optical absorption and possess an extremely high dielectric permittivity making them favorable for lossless subwavelength photonics. In addition, the proposed approach opens a possibility to observe a previously unreported peak in the dielectric function of monolayer MoS2 induced by the use of perylene-3,4,9,10-tetracarboxylic acid tetrapotassium salt (PTAS) seeding promoters for MoS2 synthesis and thus enables its applications in chemical and biological sensing. Therefore, this technique as a whole offers a state-of-the-art metrological tool for next-generation TMD-based devices
Hybrid Nanoparticles for Haloperidol Encapsulation: Quid Est Optimum?
The choice of drug delivery carrier is of paramount importance for the fate of a drug in a human body. In this study, we have prepared the hybrid nanoparticles composed of FDA-approved Eudragit L100-55 copolymer and polymeric surfactant Brij98 to load haloperidol-an antipsychotic hydrophobic drug used to treat schizophrenia and many other disorders. This platform shows good drug-loading efficiency and stability in comparison to the widely applied platforms of mesoporous silica (MSN) and a metal-organic framework (MOF). ZIF8, a biocompatible MOF, failed to encapsulate haloperidol, whereas MSN only showed limited encapsulation ability. Isothermal titration calorimetry showed that haloperidol has low binding with the surface of ZIF8 and MSN in comparison to Eudragit L100-55/Brij98, thus elucidating the striking difference in haloperidol loading. With further optimization, the haloperidol loading efficiency could reach up to 40% in the hybrid Eudragit L100-55/Brij98 nanoparticles with high stability over several months. Differential scanning calorimetry studies indicate that the encapsulated haloperidol stays in an amorphous state inside the Eudragit L100-55/Brij98 nanoparticles. Using a catalepsy and open field animal tests, we proved the prolongation of haloperidol release in vivo, resulting in later onset of action compared to the free drug
Detection of Pionium with DIRAC
The aim of the DIRAC experiment at CERN is to provide an accurate determination of S-wave pion-pion scattering lengths from the measurement of the lifetime of the pi+ pi- atom. The measurement will be done with precision comparable to the level of accuracy of theoretical predictions, formulated in the context of Chiral Perturbation Theory. Therefore, the understanding of chiral symmetry breaking of QCD will be submitted to a stringent test
Π Π°Π·ΡΠ°Π±ΠΎΡΠΊΠ° Π°Π»Π³ΠΎΡΠΈΡΠΌΠ° Π°Π²ΡΠΎΠΌΠ°ΡΠΈΠ·ΠΈΡΠΎΠ²Π°Π½Π½ΠΎΠ³ΠΎ ΠΏΡΠΎΠ΅ΠΊΡΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΠΏΡΠΎΠ²ΠΎΠ΄Π½ΠΎΠ³ΠΎ ΠΌΠΎΠ½ΡΠ°ΠΆΠ°
Nowadays, 3D electrical wiring design automation is less covered by EDA&CAD systems, than its
other aspects (solid modeling, simulation analysis, printed circuit boards development). This article
offers an algorithm of electrical wiring design automation realization and an algorithm of computer
aided development of design documentation package for electrical wiring aspect. The algorithms
are based on EDA system Altium Designer and CAD system SolidWorks. As a case study, existing
instrument manufacturing plant was takenΠ Π½Π°ΡΡΠΎΡΡΠ΅Π΅ Π²ΡΠ΅ΠΌΡ Π°Π²ΡΠΎΠΌΠ°ΡΠΈΠ·Π°ΡΠΈΠΈ ΠΏΡΠΎΠ΅ΠΊΡΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΠΎΠ±ΡΡΠΌΠ½ΠΎΠ³ΠΎ ΡΠ»Π΅ΠΊΡΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΠΌΠΎΠ½ΡΠ°ΠΆΠ°
ΡΠ΄Π΅Π»ΡΠ΅ΡΡΡ Π·Π½Π°ΡΠΈΡΠ΅Π»ΡΠ½ΠΎ ΠΌΠ΅Π½ΡΡΠ΅ Π²Π½ΠΈΠΌΠ°Π½ΠΈΡ, ΡΠ΅ΠΌ Π΄ΡΡΠ³ΠΈΠΌ Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΡΡΡΠΌ Π‘ΠΠΠ (ΡΠ²Π΅ΡΠ΄ΠΎΡΠ΅Π»ΡΠ½ΠΎΠ΅
ΠΌΠΎΠ΄Π΅Π»ΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅, Π°Π½Π°Π»ΠΈΠ· ΠΊΠΎΠ½ΡΡΡΡΠΊΡΠΈΠΉ, ΠΏΠ΅ΡΠ°ΡΠ½ΡΠΉ ΠΌΠΎΠ½ΡΠ°ΠΆ). Π Π΄Π°Π½Π½ΠΎΠΉ ΡΡΠ°ΡΡΠ΅ ΠΏΡΠ΅Π΄Π»ΠΎΠΆΠ΅Π½Ρ
Π°Π»Π³ΠΎΡΠΈΡΠΌ Π²Π½Π΅Π΄ΡΠ΅Π½ΠΈΡ ΡΠΈΡΡΠ΅ΠΌΡ Π°Π²ΡΠΎΠΌΠ°ΡΠΈΠ·ΠΈΡΠΎΠ²Π°Π½Π½ΠΎΠΉ ΡΠ°Π·ΡΠ°Π±ΠΎΡΠΊΠΈ ΠΏΡΠΎΠ²ΠΎΠ΄Π½ΠΎΠ³ΠΎ ΠΌΠΎΠ½ΡΠ°ΠΆΠ°
ΠΈ Π°Π»Π³ΠΎΡΠΈΡΠΌ Π°Π²ΡΠΎΠΌΠ°ΡΠΈΠ·ΠΈΡΠΎΠ²Π°Π½Π½ΠΎΠΉ ΡΠ°Π·ΡΠ°Π±ΠΎΡΠΊΠΈ ΠΏΠ°ΠΊΠ΅ΡΠ° ΠΏΡΠΎΠ΅ΠΊΡΠ½ΠΎΠΉ Π΄ΠΎΠΊΡΠΌΠ΅Π½ΡΠ°ΡΠΈΠΈ Π½Π°
ΠΏΡΠΎΠ²ΠΎΠ΄Π½ΠΎΠΉ ΠΌΠΎΠ½ΡΠ°ΠΆ. ΠΠ»Π³ΠΎΡΠΈΡΠΌ ΠΎΡΠ½ΠΎΠ²Π°Π½ Π½Π° ΡΠΈΡΡΠ΅ΠΌΠ°Ρ
EDA Altium Designer ΠΈ CAD SolidWorks,
ΠΈΡΠΏΠΎΠ»ΡΠ·ΡΠ΅ΠΌΡΡ
Π½Π° ΠΏΡΠ΅Π΄ΠΏΡΠΈΡΡΠΈΡΡ
ΠΏΡΠΈΠ±ΠΎΡΠΎΡΡΡΠΎΠΈΡΠ΅Π»ΡΠ½ΠΎΠ³ΠΎ ΠΏΡΠΎΡΠΈΠ»
Activity of phenoxy-imine titanium catalysts in ethylene polymerization : A quantum chemical approach
The mechanism of ethylene polymerization on phenoxy-imine (FI) titanium catalysts was studied theoretically to identify the major factors affecting the catalytic activity. Geometry optimizations of FI ligands, octahedral titanium dichloride complexes, active cationic species, and their Οβcomplexes with ethylene as well as calculations of the energy profile of chain propagation were performed at the BP86-D3 level. We found that the calculated energy gaps between frontier orbitals (HOMO and LUMO) in the active cations of the catalysts correlate with the experimental activity values. High activities of FI catalysts with Ξ±βCumyl groups were attributed to smaller HOMO-LUMO gaps due to hyperconjugation between Ο-systems of Ξ±βCumyl and (Nβaryl)salicylaldimine moieties in the active cations. The correlation provides a qualitative estimate of the catalytic activity for further design of new FI titanium complexes
Volumetric registration of magnetic nanoparticles for optimization of quantitative immunochromatographic assays for detection of small molecules
Precise quantitative and highly sensitive detection of small molecules (haptens) is highly demanded in medicine, food quality control, in vitro diagnostics, criminalistics, environmental monitoring, etc. In the present work, the magnetic method of particle quantification and the optical methods of spectral correlation and spectral phase interferometry complement each other for optimization of a quantitative assay for measuring concentrations of small molecules. The assay employs magnetic nanoparticles as labels in rapid immunochromatographic format. The approach was demonstrated with fluorescein as a model molecule. The interferometric label-free biosensors were employed for selection of optimal reagents that produced high specificity and sensitivity. The method of magnetic particle quantification counted the magnetic labels over the entire volume of the immunochromatographic membrane to provide their distribution along the test strip. Such distribution was used for optimization of such parameters as concentrations of the used reagents and of antibody immobilized on the labels, amount of the labels and conjugates of haptens with protein carriers to realize the advanced quantitative immunochromatographic assay
Volumetric registration of magnetic nanoparticles for optimization of quantitative immunochromatographic assays for detection of small molecules
Precise quantitative and highly sensitive detection of small molecules (haptens) is highly demanded in medicine, food quality control, in vitro diagnostics, criminalistics, environmental monitoring, etc. In the present work, the magnetic method of particle quantification and the optical methods of spectral correlation and spectral phase interferometry complement each other for optimization of a quantitative assay for measuring concentrations of small molecules. The assay employs magnetic nanoparticles as labels in rapid immunochromatographic format. The approach was demonstrated with fluorescein as a model molecule. The interferometric label-free biosensors were employed for selection of optimal reagents that produced high specificity and sensitivity. The method of magnetic particle quantification counted the magnetic labels over the entire volume of the immunochromatographic membrane to provide their distribution along the test strip. Such distribution was used for optimization of such parameters as concentrations of the used reagents and of antibody immobilized on the labels, amount of the labels and conjugates of haptens with protein carriers to realize the advanced quantitative immunochromatographic assay
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