A facile conversion of thio- and selenophosphoric acids and their derivatives into fluoridates by means of reaction with silver fluoride

Treatment of numerous thio- or selenophosphorus acids with aqueous silver fluoride in CHCl₃ at room temperature results in clean formation of the corresponding fluoridates. Analogous results were obtained with other phosphorothio (seleno)ates such as esters, amidates, or halides.     

Multi-frequency dynamic-mechanical thermal analysis of methyl methacrylate adhesive (MMA)

The paper presents the results of Dynamic-Mechanical Thermal Analysis (DMTA) for a selected methacrylate adhesive at the frequency range from 1 to 50?Hz and the heating rate of 1 and 3?°C/min, in the range from –70?°C to 180?°C. On the basis of the test results, the glass transition temperature was evaluated for three calculation methods. Master curves were also designated for three different reference temperatures: –20, +20 and +60?°C. Master curves were calculated using shift factors a_T - calculated by numerical method.     

Experimental investigation on using the piezoelectric and electromagnetic vibration absorbers in milling

The paper presents an active control system that counteracts the development of chatter vibration. The vibration amplitude depends on the dynamic properties of the machine tool, cutting tool and work-piece. In the paper we analyze the case when the loss of machining stability is caused by the work-piece. The proposed active control system employs electromagnet or piezoelectric actuator to suppress vibration during milling. The active control introduces damping into the system, thereby raising the critical depth of cut and reducing forced vibration amplitude. It enables stable cutting under a much wider range of cutting parameters that for the uncontrolled system. Cutting tests are performed on JAFO FYN-50 machine with mill DIN 845 B-25 K-N HSS to demonstrate an effectiveness of the proposed systems.     

On quantum iterated function systems

A Quantum Iterated Function System on a complex projective space is defined through a family of linear operators on a complex Hilbert space. The operators define both the maps and their probabilities by one algebraic formula. Examples with conformal maps (relativistic boosts) on the Bloch sphere are discussed.     

Ultrasonic investigation of magnetic nanoparticles suspension with PEG biocompatible coating

Water suspension of nanoparticles was studied by ultrasound spectroscopy. Nanoparticles have a core-shell structure with magnetic core Fe₃O₄ and surfactant shells. The surface of magnetic particles was coated with oleate sodium as the primary layer and polyethylene glycol as the secondary layer. The acoustic properties of suspensions, such as velocity and attenuation of ultrasonic waves, have been measured. From experimental data mechanical properties have been determined. Adiabatic compressibility of nanoparticles suspension decreased with increase of temperature. The changes of ultrasonic wave attenuation under the influence of the external magnetic field, show that magnetic liquids with high concentration of magnetic material (despite two surfactant shells) show tendency to aggregate.     

Evaluation of the UFXC32k photon‐counting detector for pump–probe experiments using synchrotron radiation

This paper presents the performance of a single‐photon‐counting hybrid pixel X‐ray detector with synchrotron radiation. The camera was evaluated with respect to time‐resolved experiments, namely pump–probe–probe experiments held at SOLEIL. The UFXC camera shows very good energy resolution of around 1.5 keV and allows the minimum threshold setting to be as low as 3 keV keeping the high‐count‐rate capabilities. Measurements of a synchrotron characteristic filling mode prove the proper separation of an isolated bunch of photons and the usability of the detector in time‐resolved experiments.     

Luminescence properties of epoxy resins modified with a carbazole derivative

Luminescence properties of a new material - epoxy resin with added 9-(2,3-epoxypropyl)carbazole (REPK) were studied. Absorption and photoluminescence (PL) spectra of REPK are compared with those of poly(N-vinylcarbazole) (PVK). PL in REPK is shifted to shorter wavelengths. Its intensity is higher than in PVK. REPK emits light in the range from 330 nm to 470 nm. PL spectrum of REPK could be well deconvoluted for four emission bands.     

Ultraweak spectrally resolved thermoluminescence in polymers

Spectrally resolved thermoluminescence (TL) measurements provide a lot of information concerning trapping and recombination states in various dielectric materials. As long-lived luminescence is typically weak, this technique requires a very sensitive apparatus. This paper describes the measurement system that is used for studying spectrally resolved TL and phosphorescence decay in polymers. Exemplary investigations are presented for poly(N-vinylcarbazole) (PVK) thin films. The obtained spectra clearly indicate the influence of solvents (dioxane, chlorobenzene) and excitation wavelengths on TL in PVK samples.