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Using methods of pulsed laser ablation from a silicon target in helium (He)-nitrogen (N2) gas mixtures maintained at reduced pressures (0.5–5 Torr), we fabricated substrate-supported silicon (Si) nanocrystal-based films exhibiting a strong photoluminescence (PL) emission, which depended on the He/N2 ratio. We show that, in the case of ablation in pure He gas, Si nanocrystals exhibit PL bands centered in the “red - near infrared” (maximum at 760 nm) and “green” (centered at 550 nm) spectral regions, which can be attributed to quantum-confined excitonic states in small Si nanocrystals and to local electronic states in amorphous silicon suboxide (a-SiOx) coating, respectively, while the addition of N2 leads to the generation of an intense “green-yellow” PL band centered at 580 nm. The origin of the latter band is attributed to a radiative recombination in amorphous oxynitride (a-SiNxOy) coating of Si nanocrystals. PL transients of Si nanocrystals with SiOx and a-SiNxOy coatings demonstrate nonexponential decays in the micro- and submicrosecond time scales with rates depending on nitrogen content in the mixture. After milling by ultrasound and dispersing in water, Si nanocrystals can be used as efficient non-toxic markers for bioimaging, while the observed spectral tailoring effect makes possible an adjustment of the PL emission of such markers to a concrete bioimaging task.

Recent results on studies of bottomonium and bottomonium-like states at Belle are reported. The results are obtained with a 121.4 fb−1 data sample collected with the Belle detector in the vicinity of the ϒ(5S) resonance at the KEKB asymmetric-energy e+e− collider.

The paper presents the results of investigation of the possibility of using textural statistical features to classify the images of ultrasound diagnostics of thyroid nodules. Ultrasound diagnostics has a significant potential for quantitative diagnostics. New information technologies allow us to identify characteristics that complement the classical methods of image analysis in medicine.

We elaborated a technique of pulsed laser ablation in gas mixtures (He-N 2 ), maintained under residual pressures of 0.5–5 Torr to deposit silicon (Si)-based nanostructured films on a substrate. We show that the deposited films can exhibit strong photoluminescence (PL) emission with the position of peaks depending on the pressure of ambient gas and the ratio of gases in the mixture. Nanostructured films prepared in pure He gas exhibited a strong band in the infrared range (around 760 nm) and a weak band in the green range (550 nm), which were attributed to quantum-confined excitonic states in small Si nanocrystals and radiative transitions via the localized electronic states in silicon suboxide coating, respectively. In contrast, nanostructured films prepared in He-N 2 mixtures exhibited more intense “green-yellow” PL band centered at 580 nm, which was attributed to a radiative recombination in amorphous oxynitride (a-SiN x O y ) coating of Si nanocrystals. We also present a detailed analysis of morphology of nanostructures Si-based films prepared by laser ablation. Finally, we show that the nanocrystals can be removed from the substrate and milled by ultrasound to form aqueous solutions of colloidal Si nanopartiles. The fabricated Si-based nanocrystals present a promising object for theranostics, combining imaging functionality based on PL emission and a series of therapy functionalities (photo and radiofrequency hyperthermia, photodynamic therapy).

We present the first model-independent measurement of the CKM unitarity triangle angle ϕ3 using B±→ D(KS0\\[ {K}_{\\mathrm{S}}^0 \\]π+π−π0) K± decays, where D indicates either a D0 or D¯\\[ \\overline{D} \\]0 meson. Measurements of the strong-phase difference of the D →KS0\\[ {K}_{\\mathrm{S}}^0 \\]π+π−π0 amplitude obtained from CLEO-c data are used as input. This analysis is based on the full Belle data set of 772 × 106BB¯\\[ \\overline{B} \\] events collected at the Υ(4S) resonance. We obtain ϕ3 = (5.7−8.8+10.2\\[ {5.7}_{-8.8}^{+10.2} \\]±3.5±5.7)° and the suppressed amplitude ratio rB = 0.323±0.147±0.023±0.051. Here the first uncertainty is statistical, the second is the experimental systematic, and the third is due to the precision of the strong-phase parameters measured from CLEO-c data. The 95% confidence interval on ϕ3 is (−29.7, 109.5)°, which is consistent with the current world average.

Experimental and kinetic modeling study of the ignition of a stoichiometric mixture of acetone with oxygen diluted by argon was carried out behind reflected shock waves within the temperature range of 1350-1810 K for the total mixture concentration [M50] ~ 10-5 mol/cm3. Emission signals were recorded simultaneously for three different wavelengths: OH* (λ = 308 nm) and CO 2 * (λ1 = 365 nm; λ2 = 451 nm). It was revealed that the time it takes to reach the maximum of emission of OH* and CO 2 * is practically the same over the whole temperature range. At the same time, the emission profiles of CO 2 * after the maximum was attained, recorded at λ2 = 451 nm, differ noticeably from the profiles recorded at λ1 = 365 nm. For numerical modeling of the emission profiles of OH* and CO 2 * , the corresponding sets of excitation and quenching reactions available in the literature were used. In the course of our numerical simulations we succeeded in good agreement of our own experimental and simulation results on acetone ignition and the results available in the literature for conditions under consideration.

Experimental investigations and detailed kinetic simulations of the formation of soot particles during pyrolysis of mixtures of acetylene with acetone and propane behind reflected shock waves are performed. Acetone and propane additives are found to substantially promote the process of soot formation as compared with that in acetylene-argon mixtures. Detailed kinetic simulations closely reproduce our own experimental results and published data. The kinetic model of soot formation is comprised of 4782 direct and reverse reactions involving 372 species. The predictive possibility of the kinetic model of soot formation is tested by describing the effect of acetone and propane additives to acetylene-argon mixtures on soot formation. All the kinetic parameters of the unified kinetic model are kept constant. The indicated additives enhance the soot yield because polyyne-dominated pathway of soot nucleation, characteristic of unseeded acetylene-argon mixtures, is augmented by the aromatic pathway, typical of most hydrocarbons.

The autoignition of a stoichiometric propane-oxygen mixture diluted with argon was studied behind reflected shock waves in the temperature range of 1230-1700 K at the total concentration of [M]50 ∼ 10−5 mol/cm3. Emission signals from electronically excited CH* (at λ = 429 nm) and C2* (at λ = 516 nm) radicals were recorded. It was found that the CH* and C2* emission time profiles reached their maxima almost simultaneously over the entire temperature range covered. The temperature dependence of the ignition delay time measured from the time of reaching the maximum by the CH* emission signal was simulated within the framework of several published data kinetic mechanisms. It was found that, at temperatures below 1400 K, all the kinetic models tested predict ignition delay times severalfold longer than that experimentally observed. Using a sensitivity analysis to the reaction rate constants in the induction period, the main reactions that affect the ignition delay time were identified.

In this article the results of the clock synthesizer development are shown. Different variants of voltage repeater for the system of automatic frequency tuning were analyzed. It was shown that for the purpose of energy consumption and jitter reducing the repeater on peripheral transistor can be used. The synthesizerwas created on the technology with design rules 180 nm. Scaling for the technology with design rules 90 nm is also possible.