A5061054075- Muon and positron interactions and applications
- Atomic and Molecular Physics
- Graphene research and applications
- Synthesis and characterization of novel inorganic/organometallic compounds
- Advancements in Battery Materials
- Neutrino Physics Research
- Quantum Information and Cryptography
- Nuclear physics research studies
- Quantum Mechanics and Applications
- Granular flow and fluidized beds
- Membrane Separation and Gas Transport
- Ammonia Synthesis and Nitrogen Reduction
- Marine animal studies overview
- Cellular Automata and Applications
- Organoboron and organosilicon chemistry
- Animal Vocal Communication and Behavior
- Scientific Research and Discoveries
- Quantum Computing Algorithms and Architecture
- Particle Accelerators and Free-Electron Lasers
- Glass properties and applications
- Material Dynamics and Properties
- Molecular Junctions and Nanostructures
- Advanced Thermodynamics and Statistical Mechanics
- Insect and Pesticide Research
- Bat Biology and Ecology Studies
Institute of Physics
2011-2023
Maria Curie-Skłodowska University
2010-2023
The positron annihilation lifetime spectroscopy was applied to the samples of human uterine leiomyomas and normal myometrium tissues taken from selected place uterus during a surgery.The method indicated differences in values measured parameters (lifetimes intensities) between healthy diseased tissue samples.The additional measurements were performed either darkness or presence visible light which influenced free radicals present both kind and, as result, made changes o-Ps decay intensity values.
Water confined in cylindrical pores of silica with a diameter 2 nm was studied by positron annihilation lifetime spectroscopy. Instead freezing at 273 K, the glass-like transition through viscous state to solid phase observed wide temperature range 225–188 K. Reducing vapor pressure over water allowed us obtain negative pn = −164 MPa liquid water, and changed 234–189 The dependence ortho-positronium (o-Ps) under became consistent surface tension as most liquids, opposed anomalous saturated...
Ortho-positronium lifetime and intensity were measured as a function of temperature for homologous series normal alkanes. Free volume shape concentration defects are different various phases. The lifetimes observed compared with model predictions an empty gap in the crystalline structure (at low temperatures), finite cylinder or cuboid (rotator phase) sphere (liquid). role intramolecular (nonplanar conformers) was discussed. A distinct difference dependence spectra when melting is preceded...
Positronium formation probability was investigated as a function of irradiation time and temperature for some long-chain saturated hydrocarbons (alkanes).Intensity ortho-positronium component in the lifetime spectrum depends on concentration trapped excess electrons, but also radicals ions acting electron scavengers.The results indicate existence two kinds traps; those which are not emptied by thermal treatment disappear after several days positron irradiation.
The distribution of electron trap depths in hydrocarbons seems to be continuous the range from 0.6 eV 2.2 eV. However, it that among deepest traps n-heptane also discrete ones appear as well. influence admixture other alkane on Ps intensity alkanes was examined. As far an with a shorter chain is concerned, depth and their amount remain almost same like case pure solvent. When comes essentially non-miscible solid heptane nonane, total lack accumulation effects observed. It exception mixed...
A review of data about positron annihilation lifetime in normal alkanes is presented. It was found that positronium rigid phase locates the interlamellar gap, while rotator one free volumes inside lamellae. Interesting effects seem to be: identity o-Ps and liquid long chain alkanes; appearance “premature” nonadecane with low tricosane admixture, long-term relaxation after changes temperature or pressure some binary mixtures, formation porous structure at solidification argon saturated alkane...
Abstract The study examined the effect of stearin and paraffin adulteration wax foundation on brood survival. In combs formed a stearin-adulterated (10, 30, 50% stearin, which means: 3.9, 11.7, 19.5% stearic acid, respectively), survival decreased statistically significantly ( p ≤ 0.001) compared to rates noted pure beeswax foundation. appearance resembled so-called scattered although queens oviposited normally. was caused by death young larvae, most probably due changes in properties royal...
The paper presents the application of multi-layer perceptron regressor model for predicting parameters positron annihilation lifetime spectra using example alkanes in solid phase. Good agreement calculation results was found when approach is compared with commonly used methods, e.g., LT. presented method can be as an alternative quick and accurate tool decomposition spectroscopy (PALS) general. advantages disadvantages this new are discussed. We show preliminary where trained network give...
We show that the projection evolution approach can reproduce exponential decay law. The method be potentially used to calculate lifetimes of decaying nuclei.
A numerical program calculating the energy of a positron or/and an electron near free volume in solid n-alkanes has been built. The theory interaction e(+) e(-) with this non-polar medium based on polarizability introduced. e(+)-e(-) pair bulk was compared to that calculated when forms positronium (Ps) inside volume. calculations are coupled dipole method and dipole-dipole for induced dipoles is taken into account. Furthermore, correction local permittivity taking account non-isotropic...
Positron lifetime spectra were measured for a series of odd-numbered n-alkanes from C 11 H 24 to 19 40 as function temperature and pressure.The ortho-Ps lifetimes in the rotator phase increase intensity at transition that can be explained by location Ps vicinity kink-type conformers.The relation between o-Ps molecule length described framework extended Tao-Eldrup model.One eliminate effect rise time sample illumination or application high pressure.A decrease 1 K is equivalent an pressure about 4 MPa.
A systematic study of o-Ps intensity quenching by different wavelength SWIR light was performed for a set n-alkanes which form crystal structures. The maximal able to quench determined two temperatures. results odd- and even-numbered alkanes were compared from this point view. decrease in the with shortening carbon chain found. Two kinds traps observed length exceeding 30 atoms, one kind only shorter ones. It found that binary mixture are shallower than neat
We propose a model of time evolution quantum objects which unites the unitary and measurement procedures. The allows to treat on equal footing with other dynamical variables.
The sorption of n-heptane in the SBA-3 silica was investigated using positron annihilation lifetime spectroscopy (PALS). PALS technique allows to study situ evolution pore filling by n-alkane. In dry SBA-3, free volumes attributed skeleton, micropores, mesopores as well intergranular spaces can be distinguished various ortho-positronium components. liquid appears an additional component, which monitor adsorption and desorption parameters. Filling with leads rapid, already at p/p0 = 0.08,...
The excess energy emitted during the positronium (Ps) formation in condensed matter may be released as light. Spectroscopic analysis of this light can a new method studying electronic properties materials. We report first experimental attempt, according to our knowledge, verify existence emission process. As result, possibility photons Ps is within uncertainty two different solids: an n-alkane and porous silica. However, it seems that on alkane surface not accompanied by with detection range...
It is generally assumed that weakly bound (trapped) electrons in organic solids come only from radiolytical (or photochemical) processes like ionization caused by an excited positron entering the sample. This paper presents evidence for presence of these non-irradiated samples docosane. can be due to triboelectrification process. We argue located either interlamellar gaps or spaces made non-planar conformers. Electrons former ones are more than latter ones. The origin Vis absorption...
The excess energy emitted as light, which may carry spectroscopic information during the positronium formation in condensed matter, is examined experimentally using alkanes and porous silica.