Less and Less Noble: Local Adsorption Properties of Supported Au, Ni, and Pt Nanoparticles.

In this work, we studied the local adsorption properties of gold, nickel, and platinum nanoparticles. A correlation was established between the chemical properties of massive and nanosized particles of these metals. The formation of a stable adsorption complex M-A on the nanoparticles' surface was described.

3 a,6 a-Diaza-1,4-Diphosphapentalenes: Synthesis and Complexation with the Organic π-Acceptor 1,2,4,5-Tetracyanobenzene.

The reaction of PCl with diethyl ketazine and 4-phenylcyclohexanone azine results in the formation of 1,4-dichloro-3a,6a-diaza-1,4-diphosphapentalenes which were reduced by magnesium in THF to give corresponding diazadiphosphapentalenes EtMeDDP and PhcHexDDP, containing two-coordinate phosphorus atoms. According to the CVA data, the new diazadiphosphapentalenes are strong electron donors showing oxidation peak potentials at 0.34 and 0.

Combining thermal imaging and spectral pyrometry for express temperature mapping in additive manufacturing.

A compact and low-cost two-dimensional (2D) thermal imager was developed for real-time temperature mapping of a melt pool during coaxial laser cladding (the additive manufacturing technique). The device combines a color CMOS camera and a compact spectrometer. The spectrometer was utilized for internal calibration and validation of a 2D temperature map that was acquired by the CMOS camera.

Laser Remote Sensing of Lake Kinneret by Compact Fluorescence LiDAR.

Harmful algal blooms in freshwater reservoirs became a steady phenomenon in recent decades, so instruments for monitoring water quality in real time are of high importance. Modern satellite remote sensing is a powerful technique for mapping large areas but cannot provide depth-resolved data on algal concentrations. As an alternative to satellite techniques, laser remote sensing is a perspective technique for depth-resolved studies of fresh or seawater.

Oxidation of Supported Nickel Nanoparticles at Low Exposure to O: Charging Effects and Selective Surface Activity.

The oxidation of Ni nanoparticles supported on highly oriented pyrolytic graphite was investigated under conditions of low exposure to oxygen by methods of scanning tunneling microscopy and spectroscopy. It was found that charge transfer effects at the Ni-C interface influenced the surface activity of the nanoparticles. The O dissociation and the Ni oxidation were shown to occur only at the top of the nanoparticle, while the border of the Ni-C interface was the less preferable area for these processes.

Tunable-shift stimulated Raman scattering in water by chirped 50 fs to 4.5 ps UV-pulses.

Forward stimulated Raman scattering (SRS) induced by focused 400 nm pulses chirped to different pulse durations is observed in water and heavy water. The first Stokes Raman peak shift is shown to be tunable in the range of ${{3500 {-} 4200}}\;{{\rm{cm}}^{- 1}}$ in water and ${{2450 {-} 3250}}\;{{\rm{cm}}^{- 1}}$ in heavy water. It is demonstrated that the Stokes peak shift increases for shorter pulse durations and higher intensities.

Structural Features and Properties' Characterization of Polylactic Acid/Natural Rubber Blends with Epoxidized Soybean Oil.

Because of the effort to preserve petroleum resources and promote the development of eco-friendly materials, bio-based polymers produced from sustainable resources have attracted great attention. Among them, polylactide (PLA) and natural rubber (NR) present prominent polymers with unique barrier and mechanical features. A series of samples with improved phase compatibility were obtained by blending PLA and NR using a double-rotor mixer.

In situ laser-induced breakdown spectroscopy measurements during laser welding of superalloy.

Laser-induced breakdown spectroscopy (LIBS) has been utilized for in situ diagnostics of the laser welding process. The influence of different weld spot areas (melt pool, solid weld) on LIBS signals and plasma properties has been studied in detail. Liquid metal sampling and high target surface temperature of the melt enhance LIBS plasma intensity and increase plasma temperature.

Effect of CO Molecule Orientation on the Reduction of Cu-Based Nanoparticles.

The adsorption of CO on the surface of Cu-based nanoparticles was studied in the presence of an external electric field by means of scanning tunneling microscopy (STM) and spectroscopy (STS). Nanoparticles were synthesized on the surface of a graphite support by the impregnation-precipitation method. The chemical composition of the surface of the nanoparticles was determined as a mixture of CuO, CuO and CuO oxides.

Picosecond stimulated Raman scattering at 3000 and 3430 cm OH vibrations without optical breakdown: publisher's note.

This publisher's note contains corrections to Opt. Lett.45, 5624 (2020)OPLEDP0146-959210.

Picosecond stimulated Raman scattering at 3000 and 3430 cm OH vibrations without optical breakdown.

For the first time, to the best of our knowledge, stimulated Raman scattering (SRS) of picosecond laser pulses without optical breakdown has been detected simultaneously (as the first Stokes and anti-Stokes paired components) at ∼3430 and ∼3000 vibrations of water OH band. These components were generated coaxially to the pump beam in the forward direction as axial and conical ring beams, respectively, when the pump beam was focused at the water-air interface. We suggest an explanation of these new SRS phenomena by non-collinear four-wave parametric interaction.

Biodegradable Polylactide-Poly(3-Hydroxybutyrate) Compositions Obtained via Blending under Shear Deformations and Electrospinning: Characterization and Environmental Application.

Compositions of polylactide (PLA) and poly(3-hydroxybutyrate) (PHB) thermoplastic polyesters originated from the nature raw have been obtained by blending under shear deformations and electrospinning methods in the form of films and nanofibers as well as unwoven nanofibrous materials, respectively. The degrees of crystallinity calculated on the base of melting enthalpies and thermal transition temperatures for glassy state, cold crystallization, and melting point for individual biopolymers and ternary polymer blends PLA-PHB- poly(ethyleneglycol) (PEG) have been evaluated. It has been shown that the mechanical properties of compositions depend on the presence of plasticizers PEG with different molar masses in interval of 400-1000.

Asymmetrical-cavity picosecond Raman laser at the water-air interface.

For the first time, to the best of our knowledge, we demonstrated a new type of Raman laser with asymmetrical cavity at the liquid-air interface. We observed an intriguing stimulated Raman scattering (SRS) threshold dependence when the pumping laser beam waist was transferred through the liquid-air interface, and we demonstrated a paradoxical 30-fold SRS threshold reduction in the vicinity of the water-air surface. The minimum SRS threshold was achieved when the pumping laser beam waist was located at the liquid surface.

In situ elemental analysis and failures detection during additive manufacturing process utilizing laser induced breakdown spectroscopy.

The feasibility of in situ quantitative multielemental analysis and production failures detection by laser induced breakdown spectroscopy (LIBS) has been demonstrated during direct energy deposition process in additive manufacturing. Compact LIBS probe was developed and equipped with the laser cladding head installed at industrial robot for real-time chemical quantitative analysis of key components (Ni, W) during the synthesis of high wear resistant coatings of nickel alloy reinforced with tungsten carbide particles. Owing to non-uniform distribution of tungsten carbide grains in the upper surface layer the only acceptable choice for LIBS sampling was made to the melt pool at growing clad.

Surface plasma influence on nanosecond laser ablation.

The comparison of laser ablation and plasma evolution has been carried out for a molten steel sample in the absence and in the presence of surface plasma. A continuous wave (cw) laser beam was utilized for local melting of a steel (Fe>99  wt.%) sample, but it also induced a surface plasma according to optical emission spectroscopy.

Effect of Size on Hydrogen Adsorption on the Surface of Deposited Gold Nanoparticles.

An experimental study of molecular hydrogen adsorption on single gold nanoparticles of various sizes deposited on the surface of highly oriented pyrolytic graphite (HOPG) was carried out by means of scanning tunneling microscopy and spectroscopy. The effect of size on the HOPG/Au system was established. Hydrogen was dissociatively chemisorbed on the surface of gold nanoparticles with an average size of 5⁻6 nanometers.

Optimizing laser crater enhanced Raman spectroscopy.

Raman signal enhancement by laser crater production was systematically studied for 785 nm continuous wave laser pumping. Laser craters were produced in L-aspartic acid powder by a nanosecond pulsed solid state neodymium-doped yttrium aluminum garnet laser (532 nm, 8 ns, 1 mJ/pulse), while Raman spectra were then acquired by using a commercial spectrometer with 785 nm laser beam pumping. The Raman signal enhancement effect was studied in terms of the number of ablating pulses used, the lens-to-sample distance, and the crater-center-laser-spot offset.

Optimizing laser crater enhanced Raman scattering spectroscopy.

The laser crater enhanced Raman scattering (LCERS) spectroscopy technique has been systematically studied for chosen sampling strategy and influence of powder material properties on spectra intensity enhancement. The same nanosecond pulsed solid state Nd:YAG laser (532 nm, 10 ns, 0.1-1.

Laser-induced breakdown spectroscopy for three-dimensional elemental mapping of composite materials synthesized by additive technologies.

Three-dimensional multi-elemental mapping of composite wear-resistant coatings by laser-induced breakdown spectroscopy has been demonstrated for the first time, to the best of our knowledge. Individual clads of 1560 nickel alloy reinforced with tungsten carbide were synthesized by a co-axial laser cladding technique. Electron energy dispersive x-ray spectroscopy revealed elemental maps for major elements (W, Ni, Co, Cr, Fe) but failed to measure silicon and carbon.

Combining Raman and laser induced breakdown spectroscopy by double pulse lasing.

A new approach combining Raman spectrometry and laser induced breakdown spectrometry (LIBS) within a single laser event was suggested. A pulsed solid state Nd:YAG laser running in double pulse mode (two frequency-doubled sequential nanosecond laser pulses with dozens microseconds delay) was used to combine two spectrometry methods within a single instrument (Raman/LIBS spectrometer). First, a low-energy laser pulse (power density far below ablation threshold) was used for Raman measurements while a second powerful laser pulse created the plasma suitable for LIBS analysis.

Validity of Heart Rate-Based Indices to Measure Training Load and Intensity in Elite Football Players.

Silva, P, Santos, ED, Grishin, M, and Rocha, JM. Validity of heart rate-based indices to measure training load and intensity in elite football players. J Strength Cond Res 32(8): 2340-2347, 2018-This study aimed to identify the most sensible heart rate-based indices to physical measures of training load and intensity.

Laser crater enhanced Raman spectroscopy.

Raman signal enhancement by multiple scattering inside laser crater cones was observed for the first time, to the best of our knowledge. Laser crater enhanced Raman spectroscopy (LCERS) yielded a 14-fold increase in the Raman spectra bands due to efficient multiple scattering of laser irradiation within the laser crater walls. The same pulsed Nd:YAG laser (532 nm, 10 ns) was used for both laser crater formation and Raman scattering experiments by varying the output pulse energy.

Quantifying Raman OH-band spectra for remote water temperature measurements.

Remote water temperature measurements by Raman scattering is a perspective tool for in situ and/or real-time studies for inaccessible areas such as the Arctic region. State-of-the-art laser remote temperature detection techniques are based on temperature-dependent transformation of the Raman OH stretching vibration band. This study compared different approaches quantifying Raman OH-band spectra transformation with temperature: the two-color technique, deconvolution procedure, Raman difference spectroscopy, and centroid technique.