Metal nanoparticle formation using laser ablation of targets in water by picosecond pulses is a well-developed process. Here we demonstrate how the salt and sugar being dissolved in water differently ...affect the spectral characteristics of the absorbance of the suspensions produced during ablation of silver and gold targets. We demonstrate the disappearance of the surface plasmon resonances of Ag and Au nanoparticles in the salt-containing solutions. The presence of salt does not allow for maintaining the synthesis of nanoparticles during ablation of metals contrary to the sugar-containing solution. Our nonlinear optical studies show that the saturable absorption observed in the nanoparticles-containing suspensions produced during laser ablation of silver and gold in distilled water and sugar-containing water entirely disappears in the case of the suspension produced during the ablation of these metals in salt-containing solution.
Laser-induced breakdown spectroscopy (LIBS) provides a rapid, cost-effective, and extra-sensitive analysis of geological samples to make preliminary conclusions about the presence of valuable ...elements up to the trace levels in the ore. We present the first results of a highly sensitive qualitative analysis of the core samples of geological ore from two boreholes in Latvia (Staicele 1, from a depth range of 794–802 m, and Garsene (Subate) 2A, from a depth range of 1102–1103 m) using LIBS. Our measurements using this technique confirmed the high iron content and indicated traces of rare and high in-demand metals (such as Ti, V, Co, Sm, etc.) in the sample from Staicele, renewing interest in studying boreholes across Latvia. The presented pilot studies demonstrated effectiveness and unique possibility in performing a very sensitive and time-saving qualitative analysis of the composition of samples of ores from the old but still valuable borehole cores by using the LIBS method. We compare these measurements with other methods of sample analysis.
Bioactive calcium phosphate coatings were deposited by radio-frequency magnetron sputtering from biphasic targets of hydroxyapatite and tricalcium phosphate, sintered at different mass % ratios. ...According to Raman scattering and X-ray diffraction data, the deposited hydroxyapatite coatings have a disordered structure. High-temperature treatment of the coatings in air leads to a transformation of the quasi-amorphous structure into a crystalline one. A correlation has been observed between the increase in the Ca content in the coatings and a subsequent decrease in Ca in the biphasic targets after a series of deposition processes. It was proposed that the addition of tricalcium phosphate to the targets would led to a finer coating's surface topography with the average size of 78 nm for the structural elements.
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•Targets with homogeneous mixtures of tricalcium phosphate and hydroxyapatite were used to deposit quasi-amorphous coatings.•Deposited coatings can be transformed to a crystalline state using annealing in air at 700 °С for one hour.•The structure, composition and morphology of the coating can be controlled by the composition of the biphasic target.•The addition of tricalcium phosphate to the biphasic mixture led to a finer size of the surface structural elements.
•Transition lines of neutral arsenic atom (As I) have been observed in the spectra of stellar and sub-stellar objects. An accurate and reliable data of oscillator strengths of those transitions allow ...differentiating between different evolution models of those objects. We have measured branching fractions for as i (4p25s-4p3) transition lines in 180–310 nm spectral range with higher increased accuracy using light source powered by inductively coupled radio frequency plasma (RF-ICP) source – not earlier applied in studies of atomic arsenic. The measurements were performed for 7 excited states of as i and compared with data from the literature. We combined them with the selected lifetime values reported in the literature. The transition probabilities for 26 spectral lines are obtained and compared with other experimental and theoretical data from literature. The absorption oscillator strengths for two as i (4p25s-4p3) resonance transitions (197.3 nm, f = 0.127, and 193.8 nm f = 0.059) are also reported..
Transition lines of neutral arsenic atom (As I) have been observed in the spectra of stellar and sub-stellar objects. Accurate and reliable data of oscillator strengths of those transitions allow differentiating between different evolution models of those objects. We have measured branching fractions for As I (4p25s-4p3) transition lines in 180–310 nm spectral range with higher increased accuracy using light source powered by inductively coupled radio frequency plasma (RF-ICP) source – not earlier applied in studies of atomic arsenic. The measurements were performed for 7 excited states of As I and compared with data from the literature. We combined them with the selected lifetime values reported in the literature. The transition probabilities for 26 spectral lines are obtained and compared with other experimental and theoretical data from literature. The absorption oscillator strengths for two As I (4p25s-4p3) resonance transitions (197.3 nm, f = 0.127, and 193.8 nm f = 0.059) are also reported.
We demonstrate a new instrument for in situ detection of atmospheric iodine atoms and molecules based on atomic and molecular resonance and off-resonance ultraviolet fluorescence excited by lamp ...emission. The instrument combines the robustness, light weight, low power consumption and efficient excitation of radio-frequency discharge light sources with the high sensitivity of the photon counting technique. Calibration of I2 fluorescence is achieved via quantitative detection of the molecule by Incoherent Broad Band Cavity-enhanced Absorption Spectroscopy. Atomic iodine fluorescence signal is calibrated by controlled broad band photolysis of known I2 concentrations in the visible spectral range at atmospheric pressure. The instrument has been optimised in laboratory experiments to reach detection limits of 1.2 pptv for I atoms and 13 pptv for I2, for S/N = 1 and 10 min of integration time. The ROFLEX system has been deployed in a field campaign in northern Spain, representing the first concurrent observation of ambient mixing ratios of iodine atoms and molecules in the 1–350 pptv range.
Novel immune photoluminescent biosensor, based on TiO2 nanoparticles, for retroviral leucosis detection has been developed. The photoluminescence spectra were excited by solid state laser with ...wavelength 355nm and measured in the range of 370-800nm. Original photoluminescence spectrum of TiO2 nanoparticles showed wide maximum at 515nm. The biosensitive layer was formed by immobilization of retroviral leucosis antigens on the surface of TiO2 nanoparticles. Immobilization of antigens on TiO2 surface led to UV-shift of photoluminescence spectrum and increase of PL intensity. The response to different concentrations of retroviral leucosis antibodies has been measured. The decrease of spectrum intensity and IR-shift were observed after antibodies adsorption on biosensor surface. The experimental dependences of maximum shift and intensity changes versus antibodies concentration were obtained.
Article makes roundup on role and problems of iodine impact on Global atmospheric ecosystem, tells about significant project TOAST and novel instrument made for it, and shows samples how to solve ...typical RF electronics problems with lot of modelling tools.
Electrodeless iodine and mercury iodide high-frequency discharge lamps have been made to provide intensive sources of resonance radiation of iodine and mercury in the 183-253 mm region. Both lamps ...(iodine and mercury iodide) are designed and used for monitoring the iodine level population kinetics after flash photolysis of I2.
The discovery of graphene and its unique properties has inspired researchers to try to invent other two-dimensional (2D) materials. After considerable research effort, a distinct "beyond graphene" ...domain has been established, comprising the library of non-graphene 2D materials. It is significant that some 2D non-graphene materials possess solid advantages over their predecessor, such as having a direct band gap, and therefore are highly promising for a number of applications. These applications are not limited to nano- and opto-electronics, but have a strong potential in biosensing technologies, as one example. However, since most of the 2D non-graphene materials have been newly discovered, most of the research efforts are concentrated on material synthesis and the investigation of the properties of the material. Applications of 2D non-graphene materials are still at the embryonic stage, and the integration of 2D non-graphene materials into devices is scarcely reported. However, in recent years, numerous reports have blossomed about 2D material-based biosensors, evidencing the growing potential of 2D non-graphene materials for biosensing applications. This review highlights the recent progress in research on the potential of using 2D non-graphene materials and similar oxide nanostructures for different types of biosensors (optical and electrochemical). A wide range of biological targets, such as glucose, dopamine, cortisol, DNA, IgG, bisphenol, ascorbic acid, cytochrome and estradiol, has been reported to be successfully detected by biosensors with transducers made of 2D non-graphene materials.
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