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Efficient removal of oxygen (O) impurities from titanium (Ti) scrap is necessary to accelerate the recycling of Ti scrap. However, deoxidation of Ti is extremely difficult, both thermodynamically and technically. In this study, we developed a deoxidation technique that uses Yb (a rare earth metal with high vapor pressure at elevated temperatures) to directly remove O dissolved in solid Ti. Experimental results showed that deoxidation using Yb in halide salt fluxes such as LiCl and LiF produced Ti with O concentrations of 520-1400 mass ppm. The O concentration in deoxidized Ti samples was reduced to a level lower than that in Ti under the Yb/Yb2O3 equilibrium, probably owing to the decrease in the activity of Yb2O3, which was the deoxidation product, caused by its dissolution in the fluxes. In contrast, when vapor of Yb metal and halide salts were supplied to Ti samples via a gas phase, the Ti samples were deoxidized to the same O concentration as that under the Yb/Yb2O3 equilibrium. This deoxidation limit was controlled by the Yb/Yb2O3 equilibrium. The supply of halide salt vapor did not affect the deoxidation limit. The proposed deoxidation method is expected to help scale up the recycling of Ti scrap and ensure efficient utilization of resources.

Corrosion is a degradation process on metal that happen naturally. Corrosion is one of the most common problems in the industry, resulting the corrosion prevention much needed to increase the lifetime of a material. One of the methods of corrosion prevention is cathodic protection using a sacrificial anode. This research was conducted to analyze the effect of ytterbium rare earth to the corrosion rate of sacrificial anode aluminium in seawater environment. In this research, the ytterbium rare earth used using variety of 14%, 21%, and 22%. The alloy was made using a casting process with a mini furnace, and was characterized using XRF, XRD, SEM-EDX, and Metallographic Tests. Then an immersion test was carried out for 10 days and a tafel test using the Corrtest tool and the CS Studio5 application. The electrolyte solution used is 3.5% NaCl and SCE as a reference electrode. The results show that as the element Ytterbium(Yb) increases, the grain size becomes smaller and finer. This is because Ytterbium(Yb) has a role as a grain refiner. Based on the results of the corrosion rate calculation, the lowest corrosion rate value was sample B with a Yb percentage of 21%, which had a corrosion rate value of 0.005 mm/year on the tafel test. Whereas for the 10-day immersion test, the lowest corrosion rate value was also obtained from sample B with a Yb percentage of 21%, namely 1.030 mm/year. The addition of the element Ytterbium(Yb) decreases the potential value of the sacrificial anode in seawater at room temperature with 22% Al-Yb alloy which has a potential value of the criterion of -821mV, so that only 22% Al-Yb alloy can protect the cathode.

Pulsed laser sources operating in the spectral range of 1.8 to 2.1 μm draw considerable attention due to their wide range of practical applications in many areas, including medicine, sensing, materials processing, etc. In this work, we propose a pulsed Tm-doped fiber laser scheme operating in the 2 μm spectral region with pulsed pumping at 1.57 μm. The pump source consisted of a series-connected Er-Yb pulsed master oscillator and an EDFA emitting ∼400 μs pulses with an energy of 9.3 mJ. Using this setup, we made a Tm-doped fiber laser that provided 2 mJ pulses in the 2 μm spectral region with a slope efficiency of 28% from pulses at 1.57 μm.

The title compound, diytterbium enneaoxidotritellurate(IV), was obtained in its C-type crystal structure from the binary oxides at 1073 K using a CsCl flux. It crystallizes isotypically with C-type Tm2Te3O9 and Lu2Te3O9, closing this gap of knowledge.

This paper presents the results of a study of the state of ytterbium atoms in silicon, carried out using the methods of Fourier transform infrared spectroscopy (IR) and Raman spectroscopy (RS). Silicon samples doped with ytterbium impurities were analyzed using FSM-2201 and SENTERRA II Bruker spectrometers. Registration and identification of both crystalline and amorphous phase components in the samples was carried out. The results of the study confirm that doping silicon with ytterbium impurities leads to a decrease in the concentration of optically active oxygen by 30-40%, depending on the concentration of the introduced impurities. It was also found that an increase in the number of defects leads to a broadening of the amorphous zone. It is assumed that similar dependencies exist for the Si-Yb system; however, to the best of our knowledge, similar results have not been reported previously. It is noted that the relative intensity of the three Raman bands in Si-Yb systems in the LTIOS (The light and temperature induced ordered state) state changes, and the relative intensity of Si-Si decreases. This indicates that pendant bonds are mainly formed by the breaking of Si-Si bonds. It was also observed that the light intensity causing this condition is far from that required for laser or solid phase crystallization. Using the Raman spectroscopy method, a structural transformation was discovered, expressed in a densely packed array of nanocrystals with a size of less than 11 lattice parameters. Small clusters were under strong internal stress (up to 3 GPa), which probably prevents the cluster size from increasing beyond the critical value for irreversible crystallization.

Data-driven machine learning approaches with precise predictive capabilities are proposed to address the long-standing challenges in the calculation of complex many-electron atomic systems, including high computational costs and limited accuracy. In this work, we develop a general workflow for machine learning-assisted atomic structure calculations based on the Cowan code’s Hartree–Fock with relativistic corrections (HFR) theory. The workflow incorporates enhanced ElasticNet and XGBoost algorithms, refined using entropy weight methodology to optimize performance. This semi-empirical framework is applied to calculate and analyze the excited state energy levels of the 4f closed-shell Yb I atom, providing insights into the applicability of different algorithms under various conditions. The reliability and advantages of this innovative approach are demonstrated through comprehensive comparisons with ab initio calculations, experimental data, and other theoretical results.

The lanthanide series elements are transition metals used as critical components of electronics, as well as rechargeable batteries, fertilizers, antimicrobials, contrast agents for medical imaging, and diesel fuel additives. With the surge in their utilization, lanthanide metals are being found more in our environment. However, little is known about the health effects associated with lanthanide exposure. Epidemiological studies as well as studies performed in rodents exposed to lanthanum (La) suggest neurological damage, learning and memory impairment, and disruption of neurotransmitter signaling, particularly in serotonin and dopamine pathways. Unfortunately, little is known about the neurological effects of heavier lanthanides. As dysfunctions of serotonergic and dopaminergic signaling are implicated in multiple neurological conditions, including Parkinson’s disease, depression, generalized anxiety disorder, and post-traumatic stress disorder, it is of utmost importance to determine the effects of La and other lanthanides on these neurotransmitter systems. We therefore hypothesized that early-life exposure of light [La (III) or cerium (Ce (III))] or heavy [erbium (Er (III)) or ytterbium (Yb (III))] lanthanides in Caenorhabditis elegans could cause dysregulation of serotonergic and dopaminergic signaling upon adulthood. Serotonergic signaling was assessed by measuring pharyngeal pump rate, crawl-to-swim transition, as well as egg-laying behaviors. Dopaminergic signaling was assessed by measuring locomotor rate and egg-laying and swim-to-crawl transition behaviors. Treatment with La (III), Ce (III), Er (III), or Yb (III) caused deficits in serotonergic or dopaminergic signaling in all assays, suggesting both the heavy and light lanthanides disrupt these neurotransmitter systems. Concomitant with dysregulation of neurotransmission, all four lanthanides increased reactive oxygen species (ROS) generation and decreased glutathione and ATP levels. This suggests increased oxidative stress, which is a known modifier of neurotransmission. Altogether, our data suggest that both heavy and light lanthanide series elements disrupt serotonergic and dopaminergic signaling and may affect the development or pharmacological management of related neurological conditions.

The response of isochronal and isothermal ageing on the microstructure, microhardness and electrical properties of as-cast and deformed AlYbEr and AlYbErZr alloys were studied. The addition of Zr does not affect the grain size of the alloys in the initial state. Stability of grain size in both AlYbEr and AlYbErZr as-cast alloys was proved up to ageing at 450 °C for 32 h. On the other hand recrystallized grains were already observed in cold rolled alloys after ageing at 450 °C for 2 h. It was found that Zr supports massive recrystallization of the alloys after ageing at 450 °C. The presence of L12-structured particles with dimensions about 20–100 nm was proved in the initial state of all studied aloys. Investigation of microstructure of the AlYbEr alloy after treatment up to 450 °C and 540 °C proved a presence of particles rich on Er, Yb, some of these pin dislocations. The structure of these particles could be tetragonal with the D019 or D023 lattice. In the AlYbErZr alloy many fine L12 particles (contain Er, Yb and Zr) were observed. The L12 particles were observed after ageing at 640 °C for 4 h in both alloys. The addition of Zr to the alloy highlighted the core-shell structure of these particles, moreover some of them have the double core-shell structure in the AlYbErZr alloy, where the outer shell contains Yb and Er, the inner shell contains Zr and Yb and Er was detected in the core.

Perovskite solar cells have attained high photoconversion efficiencies by changing chemical compositions of the perovskites and layered structures of the devices. However, the perovskite compounds easily decompose in air atmosphere even at the room temperature, and the photovoltaic properties are degraded by the formed defects. The motivation of this work is to solve these instability problems, and the objective the present work is to improve the film quality of the perovskite compounds by introducing lanthanide elements and decaphenylcyclopentasilane (DPPS), which were expected to contribute to decrease of the defects by the passivation effects. Here, effects of neodymium trifluoride (NdF3) or ytterbium trifluoride (YbF3) addition to CH3NH3PbI3 perovskite solar cells inserted with DPPS were investigated. Introduction of NdF3 or YbF3 increased the lattice constants and promoted crystal growth of the perovskites, and surface treatment by DPPS suppressed the PbI2 formation as surface passivation. Combined additions of NdF3 or YbF3 and DPPS contributed to the improvement of both the conversion efficiencies of the present perovskite devices and the stabilities of the photovoltaic properties by inhibiting the decomposition.

In this study, pure Sr2CeO4 (SCO) and codoped Sr2CeO4:Tm3+, Yb3+ (SCO:Tm, Yb) of powder phosphors were synthesized by a combustion technique. The concentration of Tm3+ was fixed at 0.5 mol %, while the Yb3+ doping concentration was varied from 0 to 7.0 mol %. The crystalline structure, morphology and luminescence properties were studied using X-ray diffraction (XRD), scanning electron microscope (SEM) and photoluminescence spectroscopy, respectively. The XRD analysis shows the crystalline orthorhombic phase for all synthesized samples of SCO and SCO: Tm, Yb. The SEM results show that the doped sample with 5.0 mol % Yb3+ has the lowest grain particle size of 1.92 mm. The SCO:Tm, Yb phosphors produce mainly blue and near infrared emission bands centered at 481 nm and 813 nm (under 980 nm, excitation) which corresponds respectively to 1G4→3H6 and 3H4→3H6 transitions of Tm3+. In addition, the international commission on illumination CIE coordinates were calculated for all samples taking the range of 400 – 700 nm obtaining for the 5.0 mol % Tm3+ doped sample the coordinates: (x,y) = (0.0833, 0.1671) which match with pure blue color. Due to the strong blue and near infrared emissions, the SCO:Tm, Yb phosphors could be good candidates for use in biomarkers or lighting applications.

A transparent Er3+,Yb3+:GdMgB5O10 single crystal with dimensions up to 24 × 15 × 12 mm was grown successfully by the high-temperature solution growth on dipped seeds technique from K2Mo3O10-based solvent. The grown crystal was characterized using PXRD, DSC and ATR techniques. Differential scanning calorimetry measurements and SEM analysis of the heat-treated solids revealed Er,Yb:GdMgB5O10 to be an incongruent melting compound with an onset point of 1087 °C. The absorption edge of the Er,Yb:GMBO sample is located in the region of 245 nm, which approximates a value of 4.8 eV. Absorption and emission spectra, and luminescence kinetics, were studied. The energy transfer efficiency from ytterbium to erbium ions was determined. The laser operation in continuous-wave mode was realized and output characteristics were measured. The maximal output power of 0.15 W with a slope efficiency of 11% was obtained at 1568 nm.

Ytterbium incorporated Bi2O3–B2O3–Li2O–PbO glasses have been found to be suitable for various photonics applications. In the current article, ytterbium (0.5, 1, 1.5, 2.0 and 2.5 mol%) were assorted with Bi2O3–B2O3–Li2O–PbO glass network formed by the conventional melt-quenching process. The XRD, SEM, DTA (DSC), FTIR, Optical absorption and Photoluminescence (PL) techniques employed to explore the detailed optical and structural features of the current glass samples. The analysis of XRD and SEM results confirmed the amorphous nature and their local structural changes perceived by DTA and FTIR results. From absorption data, indirect band gap energies, UE and cut of wavelength values are calculated. It is noticed that the PL properties improved with the increasing ytterbium compositional concentrations up to the level 2.5 mol%. The calculated CIE chromaticity coordinates from PL spectra confirmed quality of the light generated from the as-systemized glasses for LASER production. The obtained experimental results supported the usefulness of the developed glasses in the field of photonics.

Rare earth metals are important today, especially for heavy rare earth elements (HREEs). Dy and Yb, included in the HREE group, are widely used for permanent magnets and sensors. On the other hand, accumulated solid waste of zircon tailings is an environmental issue in mineral processing. Valuable minerals such as rare earth elements (REEs) also remain in the tailings. This study aims to determine the optimum conditions of the experimental parameters and obtain an appropriate kinetic model. The leaching process was carried out in a flat bottom three-neck flask equipped with a thermometer and reflux condenser. Observation of the effect of process conditions on recovery and kinetics analysis obtained satisfactory results. In this study, Dy and Yb leaching from solid REE-hydroxide using HCl solution afforded a total of 61.71% and 74.55% recovery of Dy and Yb, respectively, at operating conditions of 1 M HCl, 60°C, 10 g/100 mL (solid-to-liquid ratio), at 60 min (leaching duration), and 150 rpm (stirring speed). It was found that the leaching process was controlled by chemical reactions with apparent activation energies of 31.68 kJ/mol and 11.95 kJ/mol for Dy and Yb leaching, respectively.

A mixture of PbBr2 and YbBr3·nH2O in a dimethyl sulfoxide (DMSO) solution yielded single crystals of a lead halide perovskite precursor with ytterbium, bis[octakis(dimethyl sulfoxide)ytterbium(III)]pentabromidoplumbate(II) tribromide with dimethyl sulfoxide as co-crystallite, [Yb(C2H6OS)8][PbBr5]0.5Br1.5·0.5C2H6OS. The complex ions PbBr53− and Yb(DMSO)83+ are present in the crystal together with three Br− ions and DMSO molecules. X-ray crystallography revealed that the Br− ions in YbBr3 are replaced by the solvent and bound to a PbII atom or remain free. The presence of PbBr53− units, which are molecular ions with a square-pyramidal structure, is also observed. These single crystals react with a caesium chloride solution, exhibiting near-infrared (NIR) luminescence by visible photoexcitation, suggesting the formation of Yb3+-doped lead halide perovskites (CsPbBr3-xClx·Yb3+).

The single crystals of CsI-Yb2+ were grown, and their spectroscopic studies were conducted. The observed luminescence in CsI-Yb2+ is due to 5d–4f transitions in Yb2+ ions. Using time-resolved spectroscopy, spin-allowed and spin-forbidden radiative transitions of ytterbium ions at room temperature were found. The excitation spectra of Yb2+ luminescence bands were obtained in the range of 3–45 eV. The mechanism of charge compensation of Yb2+ ions in a CsI crystal was also studied, the spectrum of the thermally stimulated depolarization current was measured, and the activation energies of the two observed peaks were calculated. These peaks belong to impurity–vacancy complexes in two different positions. The charge compensation of Yb2+ occurs via cation vacancies in the nearest-neighbor and next-nearest-neighbor positions.The Yb2+ ions are promising dopants for CsI scintillators and X-ray phosphors in combination with SiPM photodetectors.

In this work, sol-gel synthesis and luminescence properties of erbium and ytterbium doped BaTiO3 (BaTiO3:Er,Yb) in porous anodic alumina are reported. Porous anodic alumina with its well-known tailor-made honeycomb structure was chosen as a template for the sol-gel synthesis of BaTiO3:Er,Yb. Porous anodic alumina was fabricated either on silicon wafer or aluminum foil. The sol corresponding to xerogel content of Ba0,76Er0,04Yb0,20TiO3 was deposited on porous anodic alumina by spinning, which was followed by drying and heat treatment at a relatively low temperature 450 °C on aluminum foil or 800 °C on silicon. Porous anodic alumina known also as an optically anisotropic structure differed in the experiments by diameter of the pores and thickness. Evidently, all fabricated samples demonstrated a roomtemperature erbium upconversion luminescence under excitation in the continuous-wave (CW) mode with a focused 980 nm laser beam of a 200 mW diode module. Erbium upconversion luminescence is characterized by the bands at 410, 523, 546, and 658 nm, corresponding to the 2H9/2 → 4I15/2, 2H11/2 → 4I15/2, 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2.

The use of multilevel quantum information carriers, also known as qudits, has attracted significant interest as a way of further scaling quantum computing devices. However, such multilevel systems usually express shorter coherence time than their two-level counterparts, which limits their computational potential. We thus propose and experimentally demonstrate two approaches for realizing the continuous dynamical decoupling of magnetic-sensitive states with mF = ±1 for qudits encoded in optical transition of trapped 171Yb+ ions. We improve the coherence time of qudit levels by an order of magnitude (more than 9 ms) without any magnetic shielding, revealing the potential advantage of the symmetry of the 171Yb+ ion energy structure for counteracting magnetic field noise. Our results are a step toward realizing qudit-based algorithms using trapped ions.

Synthesized solid solutions of (Y1-x-y-zYbxEryHoz)3Al5O12, studied their luminescence characteristics, the dependence of the intensity of the Stokes IR luminescence band 0,96-1.1 microns and 144-1.68 microns, 1,83-2,15 microns, the concentration of ions, Yb3+, Er3+, Ho3+, when excited by laser radiation with a wavelength of 0,94 microns. The analysis of the obtained relationships and determined the optimal composition of the phosphor (Y0,85-xYb0,1Er0,05Hox)3Al5O12, for maximum energy conversion efficiency from the near-infrared region at 2100 nm.

Has established the dependence of the intensity of IR-luminescence of polydisperce solid solutions Y0,84-xYb0,15Er0.01TmxAl3(BO3)4 on the ion concentration of thulium in the field of 1500 nm. Has offered the mechanisms of energy transfer between the erbium ions and thulium ions.

Has established the dependence of the intensity of IR-luminescence of polydisperce solid solutions Y1–xYbxAl3(BO3)4 on the ion concentration of dysprosium and thulium. Has offered the mechanisms of energy transfer between the ytterbium ions and impurity ions.

Solid-state erbium lasers, emitting in the spectral range of 1.5–1.6 µm, are of great interest for several industrial applications. Nowadays the Er:glass is the most widespread laser material for obtaining laser radiation at the wavelength near 1.5 µm. However, the maximal output powers of such lasers are restricted by hundreds of milliwatts because low thermal characteristics of the glass host. By this reason the search for new crystalline hosts doped with erbium ions is the actual task.In this article the investigation results of spectroscopic properties of Er3+,Yb3+:YGdSiO5 (YGSO) crystals are reported. Polarized absorption and luminescence spectra were measured. The lifetimes of energy levels were determined. The excited state absorption spectra were measured. It was shown that excited state absorption band does not overlap with gain band in the range 1.5–1.6 µm. The energy transfer efficiency from ytterbium to erbium ions was estimated. The stimulated emission and gain cross-section spectra for Er3+ ions in YGSO were calculated.

The main factors limiting the power scaling of high-peak-power high-brightness quasi-continuous wave (QCW) fiber laser oscillator and a possible solution are analyzed in this paper. The impacts of fiber length and grating parameters on the output power are studied by rate equations. Under the optimized parameters, a high-brightness QCW fiber laser oscillator with a peak power of 7.3 kW is presented experimentally by using a 24 meter long spindle-shaped Yb-doped fiber with a constant core cladding ratio, and that is the best performance of peak power and brightness in near-single-mode QCW fiber lasers at present to the best of our knowledge. The corresponding pulse energy is 0.57 J and the beam quality M2 factor is about 1.43 under the condition of repetition frequency of 1 kHz and pulse width of 100 μs. The details are analyzed, and also the limiting factors of further power scaling, strategies of suppressing nonlinear effects and the principle of optical device parameter optimization.

Ytterbium (Yb) containing magnesium alloys have aroused extensive interest due to their excellent mechanical properties after thermomechanical processing and heat treatment. Unfortunately, the sole effect of Yb addition on the microstructure and mechanical properties of pure Mg matrix remains uncertain to date. In this work, the effects of Yb concentration on the texture development and tensile properties of pure Mg matrix during hot extrusion and the subsequent annealing were systematically investigated. The results revealed that the constitutional supercooling induced by Yb addition refined the as-cast microstructure but exerted a negligible effect on the original columnar grain morphology. When extruded at 300 °C, the dynamic recrystallization (DRX) process was considerably retarded. The in-grain misorientation axes (IGMA) analysis combined with TEM observation indicated that non-basal slips operated with increasing Yb concentration. Specifically, the prismatic slip should be robustly activated in Mg–1.0 Yb extrudate, promoting the formation of the texture with {10–10} plane normal to the extrusion direction (ED), while for the Mg–2.0 Yb counterpart, the increased activity of pyramidal slip and the relaxation of basal/ dislocations generated an ED-tilted texture component. The preferential grain growth dominated the subsequent annealing texture development at 400 °C when a comparable grain size was achieved. An obvious ED-tilted texture intensity with the peak around was observed in Mg–2.0 Yb alloy, which was primarily caused by grains with the basal orientation vanished and with the non-basal orientations intensified due to a higher concentration of Yb solute. Favored by the grain refinement, the Mg–2.0 Yb extrudate exhibited a high tensile yield strength of 304 ± 3.5 MPa, while the subsequently annealed counterpart presented a favorable elongation to failure of 14.8 ± 1.2%, which mainly due to the homogeneous grain structure, weak ED-tilted texture, and dissolution of coarse phases after high-temperature annealing.

This work shows a study of pressure gas sensing using an optical fiber interferometer inside a gas cell; here, a thin-core fiber modal interferometer (TCFMI) is fabricated using two distinct types of fiber, a single-mode fiber (SMF model 1060XP) and thin-core fiber (TCF model 460 HP). This interferometric structure is set into a ring fiber laser with an ytterbium-doped fiber (YDF) pumped with a 980 nm laser diode. The TCFMI interference spectrum shows wavelength shifting and amplitude variations as the chamber pressure is altered in the range of 5 to 40 PSI; these changes control the ring fiber laser cavity response linearly and lead to good stability in its wavelength operation in a range of 30 nm. The proposed interferometer operates as a wavelength-selective filter in the fiber ring laser cavity. The single laser emission shows a side mode suppression ratio of 34.17 dB. The fiber ring laser is a reliable alternative for air pressure sensing applications.

Pure and Yb3+-doped ZnS (YbxZn1−xS) nanoparticles were prepared in this research via hydrothermal route at 160 °C and 12 h. The obtained products were characterized by means of Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and X-ray powder diffraction (XRPD). XRPD analyses displayed that the particles were perfectly crystallized and assigned to the cubic structure of zinc sulfide. TEM and SEM images indicated that the sizes of particles were in the range of 10-80nm.The photocatalytic performance of Yb3+-doped ZnS nanoparticles was assessed in an aqueous solution by observing the decolorization of Tartrazine (Yellow 5) in the process of visible-light radiation. The degradation percent of Yb0.06Zn0.94S and bare ZnS was 92.15 and 22.10% after 100 min of treatment, respectively. 6% Yb3+-doped ZnS nanoparticles demonstrated the highest removal efficiency between various values of dopant agent. It was noticed that the existence of inorganic ions like C2O42−, I−and other radical scavengers like benzoquinone and butanol decreased the decolorization efficiency.

Solid-state lasers emitting in the 1.5–1.6 μm spectral range are very promising for eye-safe laser range finding, ophthalmology, fiber-optic communication systems, and optical location. The aim of this work is the investigation of spectrosposcopic and laser properties of gain medium based on borate crystal for abovementioned lasers.Spectroscopic and laser properties of Er,Yb:YAl3(BO3)4 crystals with different concentrations of dopants were investigated. Polarized absorption and emission cross-section spectra were determined. The ytterbium- erbium energy transfer efficiency was estimated. The maximal energy transfer efficiency up to 97 % was obtained for Er(4 at.%),Yb(11 at.%):YAl3(BO3)4 crystal.The laser operation of heavily doped crystals with erbium concentration up to 4 аt.% (2.2^1020 cm^3) was realized. By using of Er(2 at.%),Yb(11 at.%):YAl3(BO3)4 crystal a maximal continuous- wave (CW) output power of 1.6 W was obtained at 1522 nm with slope efficiency of 32 %. By using of Er(4 at.%),Yb(11 at.%):YAl3(BO3)4 crystal a maximal peak output power up to 2.2 W with slope efficiency of 40 % was realized in quasi-continuous-wave regime of operation. The spatial profile of the output beam was close to TEM00 mode with M2 < 1.2 during all laser experiments.Based on the obtained results, it can be concluded that Er,Yb:YAl3(BO3)4 crystals are promising active media for lasers emitting in the spectral range of 1.5-1.6 pm for the usage in laser rangefinder and laser- induced breakdown spectroscopy systems, and LIDARs.

Rare earth elements (REEs) are valuable and strategically important in many high-technology areas, such as laser technology, pharmacy and metallurgy. The main methods of REE recovery are precipitation, extraction and sorption, in particular ion exchange using various sorbents, which allow to perform selective recovery and removal of associated components, as well as to separate rare earth metals with similar chemical properties. The paper examines recovery of ytterbium in the form of coordination compounds with Trilon B on weakly basic anion exchange resin D-403 from nitrate solutions. In order to estimate thermodynamic sorption parameters of ytterbium anionic complexes, ion exchange process was carried out from model solutions under constant ionic strength specified by NaNO3, optimal liquid to solid ratio, pH level, temperatures 298 and 343 K by variable concentrations method. Description of thermodynamic equilibrium was made using mass action law formulated for ion exchange equation and mathematically converted to linear form. Values of equilibrium constants, Gibbs free energy, enthalpy and entropy of the sorption process have been calculated. Basing on calculated values of Gibbs energy, a sorption series of complex REE ions with Trilon B was obtained over anion exchange resin D-403 from nitrate solutions at temperature 298 K. Sorption characteristics of anion exchange resin have been estimated: total capacity, limiting sorption of complex ions, total dynamic capacity and breakthrough dynamic capacity.

Reaction of 2-(4,4-dimethyl-2-oxazolin-2-yl)aniline (H2-L1) with one equivalent of Na[N(SiMe3)2] in toluene afforded pale-yellow crystals of tetrameric poly[bis[μ3-2-(4,4-dimethyl-2-oxazolin-2-yl)anilinido][μ2-2-(4,4-dimethyl-2-oxazolin-2-yl)aniline]tetrasodium(I)], [Na4(C11H13N2O)4]n or [Na4(H-L1)4]n (2), in excellent yield. Subsequent reaction of [Na4(H-L1)4]n (2) with 1.33 equivalents of anhydrous YbCl3 in a 50:50 mixture of toluene–THF afforded yellow crystals of tris[2-(4,4-dimethyl-2-oxazolin-2-yl)anilinido]ytterbium(III), [Yb(C11H13N2O)3] or Yb(H-L1)3 (3) in moderate yield. Direct reaction of three equivalents of 2-(4′,4′-dimethyl-2′-oxazolinyl)aniline (H2-L1) with Yb[N(SiMe3)2]3 in toluene resulted in elimination of hexamethyldisilazane, HN(SiMe3)2, and produced Yb(H-L1)3 (3) in excellent yield. The structure of 2 consists of tetrameric Na4(H-L1)4 subunits in which each Na+ cation is bound to two H-L1 bridging bidentate ligands and these subunits are connected into a polymeric chain by two of the four oxazoline O atoms bridging to Na+ cations in the adjacent tetramer. This results in two 4-coordinate and two 5-coordinate Na+ cations within each tetrameric unit. The structure of 3 consists of a distorted octahedron where the bite angle of ligand L1 ranges between 74.72 (11) and 77.79 (11) degrees. The oxazoline (and anilide) N atoms occupy meridional sites such that for one ligand an anilide nitrogen is trans to an oxazoline nitrogen while for the other two oxazoline N atoms are trans to each other. This results in a significantly longer Yb—N(oxazoline) distance [2.468 (3) Å] for the bond trans to the anilide compared to those for the oxazoline N atoms trans to one another [2.376 (3), 2.390 (3) Å].

The rapidly expanding utilization of lanthanides (Ln) for the development of new technologies, green energies, and agriculture has raised concerns regarding their impacts on the environment and human health. The absence of characterization of the underlying cellular and molecular mechanisms regarding their toxicity is a caveat in the apprehension of their environmental impacts. We performed genomic phenotyping and molecular physiology analyses of Saccharomyces cerevisiae mutants exposed to La and Yb to uncover genes and pathways affecting Ln resistance and toxicity. Ln responses strongly differed from well-known transition metal and from common responses mediated by oxidative compounds. Shared response pathways to La and Yb exposure were associated to lipid metabolism, ion homeostasis, vesicular trafficking, and endocytosis, which represents a putative way of entry for Ln. Cell wall organization and related signaling pathways allowed for the discrimination of light and heavy Ln. Mutants in cell wall integrity-related proteins (e.g., Kre1p, Kre6p) or in the activation of secretory pathway and cell wall proteins (e.g., Kex2p, Kex1p) were resistant to Yb but sensitive to La. Exposure of WT yeast to the serine protease inhibitor tosyl phenylalanyl chloromethyl ketone mimicked the phenotype of kex2∆ under Ln, strengthening these results. Our data also suggest that the relative proportions of chitin and phosphomannan could modulate the proportion of functional groups (phosphates and carboxylates) to which La and Yb could differentially bind. Moreover, we showed that kex2∆, kex1∆, kre1∆, and kre6∆ strains were all sensitive to light Ln (La to Eu), while being increasingly resistant to heavier Ln. Finally, shotgun proteomic analyses identified modulated proteins in kex2∆ exposed to Ln, among which several plasmalemma ion transporters that were less abundant and that could play a role in Yb uptake. By combining these different approaches, we unraveled that cell wall components not only act in Ln adsorption but are also active signal effectors allowing cells to differentiate light and heavy Ln. This work paves the way for future investigations to the better understanding of Ln toxicity in higher eukaryotes.

Accurate estimation of individual feed intake (FI) of pigs could help better understand the variation in performance between individual animals. We studied dual marker methods to estimate individual FI in pigs. This method is based on the measurement of the ratio between two indigestible markers in faeces. Twelve 6.5-week-old individually housed male pigs were assigned to one of three oral dosing treatments supplying 180 mg of ytterbium chloride (YbCl3)/day and 111 mg of dotriacontane (C32)/day as reference markers, either once (R1), three times (R3) or five times (R5) daily. Pigs were offered a diet containing 0.46 g/kg of chromium chloride (CrCl3) and 0.15 g/kg of hexatriacontane (C36) as in-feed markers. The experiment lasted for 10 days: days −5 to 0: adaptation; days 1–3: dosing of reference marker; days 2–4: total faecal collection. Spot faecal samples were taken on day 3 at 1200 h, 1700 h and on day 4 at 0700 h. Pigs were fed restrictedly three times daily, at 133.6 g/kg BW0.60. Individual measured FI was recorded daily and was compared to predicted FI using the ratio of the dual marker pairs (Yb:Cr and C32:C36), both in total faecal collection and spot samples. Due to unequal variance, R1 pigs were omitted from the statistical treatment comparison. When using total faecal collection samples, the absolute prediction error (APE) (predicted FI minus measured FI) in R3 and R5 pigs was numerically lower than in R1 pigs, regardless of the marker pair used. The APE measured by C32:C36 was numerically lower than measured by Yb:Cr at all frequencies, and significantly (P = 0.039) in R3 pigs (C32:C36: 0.15 ± 0.02 kg/day; Yb:Cr: 0.29 ± 0.04 kg/day). This was related to a larger difference in faecal recovery between Yb and Cr compared with C32 and C36. Daily total faecal collection revealed that for R3 pigs, starting faecal collections 2 days after the onset of provision of the reference marker improved the APE when compared with starting after 1 day. When using C32:C36 to predict feed intake, pooled, but not single spot samples gave similar APEs compared with total faecal collections. Therefore, we recommend dosing the reference marker three times per day for 2 days on days 1 and 2, combined with pooled spot faecal sampling collected on days 3 and 4. In this way, absolute prediction errors of 10%-15% of simultaneously measured intakes of multiple nutrient resources in a complex housing system are feasible using the dual marker technique.

The individual separation of lanthanides is very complex due to the similarities between these elements. Ion-exchange separations with carboxylic acids are widely studied, but the importance of pH is overlooked. This study used citric acid to evaluate Lu and Yb separation with Dowex 50W-X8. The separation was monitored by X-ray fluorescence. Five new structures of Lu and Yb citrates are proposed. Better separation occurs when the pH of the ligand is pH 4.5, where a mononuclear structure is formed. Conversely, polynuclear structures are formed at higher pH, and separation fails. X-ray diffraction reveals different phases at each pH value, and FTIR results support the proposed structures.

Sol-gel technology has attracted attention in the fabrication of diverse luminescent materials and thin film structures, with forms that range from powders to microcavities. The optical properties of sol-gel-derived structures depend on the sol composition, deposition, and heat treatment conditions, as well as on the film thicknesses and other factors. Investigations on the upconversion luminescence of lanthanides in film structures and materials are also ongoing. In this study, we synthesized three different types of materials and film structures using the same sol, which corresponded to a Ba0.76Er0.04Yb0.20TiO3 xerogel, as follows: (a) the target form, which used the explosive compaction method for sol-gel-derived powder; (b) single-layer spin-on xerogel films annealed at 450 and 800 °C; and (c) microcavities with an undoped SiO2/BaTiO3 Bragg reflector surrounding a Ba0.76Er0.04Yb0.20TiO3 active layer. The BaTiO3:(Er,Yb)/SiO2 microcavity exhibited an enhancement of the upconversion luminescence when compared to the BaTiO3:(Er,Yb) double-layer film fabricated directly on a crystalline silicon substrate. The reflection spectra of the BaTiO3:(Er, Yb)/SiO2 microcavity annealed at 800 °C demonstrated a deviation of the maxima of the reflection within 15% for temperature measurements ranging from 26 to 120 °C. From the analyses of the transmission and reflection spectra, the optical band gap for the indirect optical transition in the single layer of the BaTiO3:(Er,Yb) spin-on film annealed at 450 °C was estimated to be 3.82 eV, while that for the film annealed at 800 °C was approximately 3.87 eV. The optical properties, upconversion luminescence, and potential applications of the BaTiO3:(Er,Yb) sol-gel-derived materials and structures are discussed in this paper.

In this contribution, we present the spectroscopic study of two NIR emitting hydrophobic heteroleptic (R,R)-YbL1(tta) and (R,R)-NdL1(tta) complexes (with tta = 2-thenoyltrifluoroacetonate and L1 = N,N′-bis(2-(8-hydroxyquinolinate)methylidene)-1,2-(R,R or S,S)-cyclohexanediamine), both in methanol solution and embedded in water dispersible and biocompatible poly lactic-co-glycolic acid (PLGA) nanoparticles. Thanks to their absorption properties in a wide range of wavelengths extending from the UV up to the blue and green visible regions, the emission of these complexes can be effectively sensitized using visible radiation, which is much less harmful to tissues and skin than the UV one. The encapsulation of the two Ln(III)-based complexes in PLGA allows us to preserve their nature, making them stable in water and to test their cytotoxicity on two different cell lines, with the aim of using them in the future as potential bioimaging optical probes.

We propose and demonstrate a cladding-pumped, erbium-ytterbium co-doped fiber amplifier (EYDFA) scheme based on dual wavelength auxiliary signal injection technique to solve the issue of the backward Yb-ASE self-lasing under strong pumping for the high-power fiber amplification of 1.5-μm kHz-linewidth linearly-polarized laser signal. With the dual wavelength auxiliary signal of 1030 and 1040 nm injection, the allowable maximum pump power without triggering the backward Yb-ASE self-lasing can be greatly increased due to the relieving effect on the inhomogeneous gain broadening. For an EYDFA with 3.8-m erbium-ytterbium co-doped double-clad fiber, the net output power is improved to 13.8 W, while the linewidth of the amplified single-transverse-mode linearly-polarized 1560 nm laser signal is still only 3.5 kHz. The SBS effect is observed to be trivial during the fiber amplification.

We report, for the first time to our knowledge, a diode-pumped continuous-wave microchip Er,Yb:YMgB5O10 laser. The purpose of this work was to study the growth technique, spectroscopic properties and continuous-wave laser performance of Er3+,Yb3+:YMgB5O10 novel crystal. Absorption and luminescence spectra as well as kinetics of luminescence decay were studied. Ytterbium-erbium energy transfer efficiency was determined. The output characteristics (output power, slope efficiency, laser wavelength) of Er3+,Yb3+:YMgB5O10 laser were determined.Two intensive absorption bands with peaks centered at 937 nm and 976 nm were observed in the absorption spectra at the wavelength near 1 μm. The maximum value of absorption cross-section was determined to be 1.5·10–20 cm2 at 976 nm for polarization E//Ng . A number of narrow lines were observed in the absorption spectra in the 1425–1575 nm spectral range (transition 4I15/2 → 4I13/2 of erbium ions). The lifetime of the upper laser level 4I13/2 of Er3+ ions was determined to be 390 ± 20 μs. The ytterbium-erbium energy transfer efficiency for YMgB5O10 crystal with 2 at.% of Er3+ and 11 at.% for Yb3+ was close to 84 %. The maximal continuous-wave output power of 0.2 W with slope efficiency of 8 % regarding to absorbed pump power was realized at the wavelength of 1570 nm. With the improvement of cavity parameters the output laser performance of the Er,Yb:YMgB5O10 crystal can be further enhanced.Taking into account high thermal conductivity of ≈ 6.2 W·m–1·K–1, the Er,Yb:YMgB5O10 crystal can be considered as a good gain medium for 1.5 μm lasers for applications in laser rangefinder and LIDAR systems.

Reaction of 2-(anthracen-9-yl)phenol (HOPhAn, 1) with divalent Yb[N(SiMe3)2]2·2THF in THF–toluene mixtures affords the mixed-valence YbII–YbIII dimer {[2-(anthracen-9-yl)phenolato-κO]bis(tetrahydrofuran)ytterbium(III)}-tris[μ-2-(anthracen-9-yl)phenolato]-κ4O:O;κO:1,2-η,κO-{[2-(anthracen-9-yl)phenolato-κO]ytterbium(II)} toluene trisolvate, [Yb2(C20H13O)5(C4H8O)2]·3C7H7 or [YbIII(THF)2(OPhAn)](μ-OPhAn)3[YbII(OPhAn)]·3C7H7 (2), as the major product. It crystallized as a toluene trisolvate. The Yb—O bond lengths in the crystal structure of this dimer clearly identify the YbII and YbIII centres. Interestingly, the formally four-coordinate YbII centre shows a close contact with one anthracene C—C bond of a bridging OPhAn ligand, bringing the formal coordination number to five.

Europium bis(tetraphenylborate) [Eu(thf)7][BPh4]2⋅thf containing a fully solvated [Eu(thf)7]2+ cation, was synthesized by protolysis of “EuPh2” (from Eu and HgPh2) with Et3NHBPh4, and the structure was determined by single-crystal X-ray diffraction. Efforts to characterize the putative “Ph2Ln” (Ln = Eu, Yb) reagents led to the synthesis of a mixed-valence complex, [(thf)3YbII(μ-Ph)3YbIII(Ph)2(thf)]⋅2thf, resulting from the reaction of Yb metal with HgPh2 at a low temperature. This mixed-valence YbII/YbIII compound was studied by 171Yb-NMR spectroscopy and single-crystal X-ray diffraction, and the oxidation states of the Yb atoms were assigned.

Reaction of [YbCp2(dme)] (Cp = cyclopentadienyl, dme = 1,2 dimethoxyethane) with bis(diphenylphosphano)methane dioxide (H2dppmO2) leads to deprotonation of the ligand H2dppmO2 and oxidation of ytterbium, forming an extremely air-sensitive product, [YbIII(HdppmO2)3] (1), a six-coordinate complex with three chelating (OPCHPO) HdppmO2 ligands. Complex 1 was also obtained by a redox transmetallation/protolysis synthesis from metallic ytterbium, Hg(C6F5)2, and H2dppmO2. In a further preparation, the reaction of [Yb(C6F5)2] with H2dppmO2, not only yielded compound 1, but also gave a remarkable tetranuclear cage, [Yb4(µ-HdppmO2)6(µ-F)6] (2) containing two [Yb(µ-F)]2 rhombic units linked by two fluoride ligands and the tetranuclear unit is encapsulated by six bridging HdppmO2 donors. The fluoride ligands of the cage result from C-F activation of pentafluorobenzene and concomitant formation of p-H2C6F4 and m-H2C6F4, the last being an unexpected product.

The reduction mechanisms of Yb(III) on W electrodes in molten LiCl-KCl-YbCl3 were explored at 773 K, and the diffusion coefficient of Yb(III) was determined. Then, various electrochemical techniques were employed to investigate the electroreduction of Yb(III) in molten LiCl-KCl on a liquid Pb film and Pb electrode. Electrochemical signals were associated with forming Pb3Yb, PbYb, Pb3Yb5, and PbYb2. The deposition potentials and equilibrium potentials of four Pb-Yb intermetallics were obtained through open-circuit chronopotentiometry. Metallic Yb was extracted by potentiostatic electrolysis (PE) on a liquid Pb electrode, and XRD analyzed the Pb-Yb alloy obtained at different extraction times. The recovered Yb was found in the form of Pb3Yb and PbYb intermetallics. The extraction efficiency of Yb was calculated according to ICP analysis results, and extraction effectivity could attain 94.5% via PE at −1.86 V for 14 h.

Currently, laser systems based on active elements doped with Yb3+ with simultaneously high pulse repetition rates and high peak power are in demand for many applications. High thermal load of active elements is the primary limiting factor for average power scaling. Experimental investigation of temperature distribution in active elements is of particular importance for estimation of cooling efficiency and for thermal processes’ monitoring. In the present work, the method of dynamic laser thermometry is proposed for temperature distribution investigation within cryogenically cooled Yb3+-doped active elements. The method is based on the dependence of the Yb3+ ion absorption cross-section on temperature at a wavelength of 1030 nm. The method was tested to study the 2D temperature map of the Yb:YAG active element of the high-power, diode-pumped, cryogenically cooled laser amplifier. The best measurement accuracy ±3 K is achieved at the maximal temperature 176 K. The results of numerical simulation are in good agreement with the experimental data. On the basis of the investigation, the quality of the cooling system is evaluated. The advantages and other possible applications of the method are discussed.

Magnesium-based alloys are widely used in the construction, automotive, aviation and medical industries. There are many parameters that can be modified during their synthesis in order to obtain an alloy with the desired microstructure and advantageous properties. Modifications to the chemical composition and parameters of the synthesis process are of key importance. In this work, an Mg-based alloy with a rare-earth element addition was synthesized by means of mechanical alloying (MA). The aim of this work was to study the effect of milling times on the Mg-based alloy with a rare-earth addition on its structure and microhardness. A powder mixture of pure elements was milled in a SPEX 8000D high energy shaker ball mill under an argon atmosphere using a stainless steel container and balls. The sample was mechanically alloyed at the following milling times: 3, 5, 8 and 13 h, with 0.5 h interruptions. The microstructure and hardness of samples were investigated. The Mg-based powder alloy was examined by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and using a Vickers microhardness test. The results showed that microhardness of the sample milled for 13 h was higher than that of those with milling time of 3, 5 and 8 h.

The main purpose of this work is to thoroughly describe the implementation protocol of laser-induced breakdown spectroscopy (LIBS) method in the plant analysis. Numerous feasibility studies and recent progress in instrumentation and trends in chemical analysis make LIBS an established method in plant bioimaging. In this work, we present an easy and straightforward phytotoxicity case study with a focus on LIBS method. We intend to demonstrate in detail how to manipulate with plants after exposures and how to prepare them for analyses. Moreover, we aim to achieve 2D maps of spatial element distribution with a good resolution without any loss of sensitivity. The benefits of rapid, low-cost bioimaging are highlighted.In this study, cabbage (Brassica oleracea L.) was treated with an aqueous dispersion of photon-upconversion nanoparticles (NaYF4 doped with Yb3+ and Tm3+ coated with carboxylated silica shell) in a hydroponic short-term toxicity test. After a 72-hour plant exposure, several macroscopic toxicity end-points were monitored. The translocation of Y, Yb, and Tm across the whole plant was set by employing LIBS with a lateral resolution 100 µm. The LIBS maps of rare-earth elements in B.oleracea plant grown with 50 μg/mL nanoparticle-treated and ion-treated exposures showed the root as the main storage, while the transfer via stem into leaves was minimal. On the contrary, the LIBS maps of plants exposed to the 500 μg/mL nanoparticle-treated and ion-treated uncover slightly different trends, nanoparticles as well as ions were transferred through the stem into leaves. However, the main storage organ was a root as well.

The results of a series of pump–probe spectral hole-burning experiments are presented on Yb3+- or Er3+-doped Li6Y(BO3)3 (LYB) single crystals in the temperature range of 2–14 K and 9–28 K, respectively. The spectral hole has a complex structure for Yb3+ with superposed narrow and broad bands, while a single absorption hole has been observed for Er3+. Population relaxation times (T1) at about 850 ± 60 μs and 1010 ± 50 μs and dipole relaxation times (T2) with values of 1100 ± 120 ns and 14.2 ± 0.3 ns have been obtained for the two components measured for the Yb3+:2F7/2—2F5/2 transition. T1 = 402 ± 8 μs and T2 = 11.9 ± 0.2 ns values have been found for the Er3+:4I15/2—4I11/2 excitation. The spectral diffusion rate at about 1 and 5 MHz/ms has been determined for the narrow and broad spectral line in Yb3+-doped crystal, respectively. The temperature dependence of the spectral hole halfwidth has also been investigated.

A transparent Yb:YMgB5O10 single crystal with dimensions up to 25 × 23 × 25 mm and weight 10.337 g was grown using a high-temperature solution growth on dipped seeds technique with a K2Mo3O10 solvent. The Yb3+ concentration was calculated to be 4.7 at.% (NYb = 3.71 × 1020 atoms/cm3) with a distribution coefficient Kd of 0.59. The grown crystal was characterized by means of PXRD, TGA-DSC and ATR-FTIR techniques. The spectroscopic characteristics of the Yb:YMgB5O10 crystal were demonstrated. Absorption cross-section spectra were produced. The luminescence spectra of the Yb:YMgB5O10 crystal were measured in the spectral range of 950–1100 nm. The luminescence kinetics of the 2F5/2 energy level were investigated and the lifetime was determined.

The search for new crystalline host materials for the usage in lasers emitting in the eye-safe spectral range of 1.5–1.6 µm is an important task. The aim of this work was to study the growth technique, spectroscopic properties and laser characteristics of new active media – crystals Er3+,Yb3+:Ca2RE2(BO3)4 (RE=Y, Gd).Calcium-yttrium Er3+,Yb3+:Ca3Y2 (BO3)4 (CYB) and calcium-gadolinium Er3+,Yb3+: Ca2 Gd 2(BO3)4 (CGB) oxoborate crystals co-doped with erbium and ytterbium ions were investigated. Polarized absorption and emission cross-section spectra were determined. The lifetimes of 4I11/2 and 4I13/2 energy levels of Er3+ ions were measured and ytterbium-erbium energy transfer efficiencies were estimated. The calculation of the gain cross-section spectra was performed. By using of Er3+,Yb3+: Ca2 RE 2(BO3)4 (RE=Y, Gd) crystals the laser performance was realized, for the first time to the best of our knowledge. The laser characteristics were studied in a quasi-CW (QCW) laser operation.The wide band with a peak at the wavelength of 976 nm is observed in the absorption spectra of both crystals. This peak coincides with the emission wavelength of the pump laser diodes for Yb-doped active media. The maximum value of absorption cross-section was 1.7 × 10–20 cm2 for polarization E // b for both crystals. The lifetimes of the upper laser level 4I13/2 of Er3+ ions were 580 ± 30 μs and 550 ± 30 μs for Er,Yb:CYB and Er,Yb:CGB crystals, respectively. The energy transfer efficiencies from ytterbium to erbium ions for an Er,Yb:CYB and Er,Yb:CGB crystals were 94 % and 96 %, respectively. According to gain spectrum of the Er,Yb:CYB crystal the gain band peak is centered at the wavelength of 1530 nm. The maximum QCW output power was 0.5 W with slope efficiency of 13 % regarding to absorbed pump power for an Er,Yb: CYB crystal. The laser beam parameter M2 did not exceed < 1.5.Based on the obtained results, it can be concluded that these crystals are promising active media for lasers emitting in the spectral range of 1.5–1.6 μm for the usage in laser rangefinder and laser-induced breakdown spectroscopy systems, and LIDARs.

Grazing management has an important impact on dairy ruminants’ performance. References on the intake and milk yield of dairy goats under strip-grazing systems in temperate regions are scarce. In order to study the effect of pasture allowance on pasture intake (PI), milk yield and grazing behaviour, a trial was carried out in spring with 36 Alpine goats in mid-lactation. Three daily pasture allowances (PA=1.7, 2.6 and 3.5 kg dry matter (DM)/day, namely Low, Medium and High, respectively) were compared in a 3 × 3 Latin square design replicated six times during three successive 14-day periods. Goats individually received 268 g DM of concentrate twice daily at each milking and had access 11 h/day to pasture (from 0830 to 1600 h and from 1730 to 2100 h). Pasture intake increased with PA, and more so between Low and Medium than between Medium and High (+216 v. +101 g DM/kg DM of PA). Milk yield was lower on Low than on Medium and High (2.79 v. 3.13 kg/day), as were milk fat and protein yields. Grazing time averaged 476 min/day and was lowest on Low and greatest on Medium. Pasture intake rate was 30 g DM/h lower on Low and Medium than on High. It is concluded that under temperate conditions, when goats are supplemented with 536 g DM of concentrate and have enough access time to pasture (11 h/day), a medium pasture allowance close to 2.6 kg DM/day may be sufficient to maximise milk yield.

The noise and gain characteristics of pulsed double-pass (DP) amplifiers operating at low repetition rates are analyzed theoretically and experimentally. The Frantz-Nodvik equations are extended to realize rapid calculation of signal gain in DP fiber amplifiers. At the same time, the rate equations are used to compute the evolution of amplified spontaneous emission (ASE) noise. The effects of the pump scheme, the input energy, and the insertion loss on the gain and noise characteristics are discussed. Based on the simulation results, a new structure Yb-doped DP amplifier is proposed. The experimental results show that the small-signal gain of the DP amplifier can exceed 50 dB. In particular, the average ASE background of the DP amplifier at high-energy output is lower than that of the single-pass amplifier at the same output. This result is quite different from continuous-wave fiber amplifiers.

Erbium upconversion (UC) photoluminescence (PL) from sol-gel derived barium titanate (BaTiO3:Er) xerogel structures fabricated on silicon, glass or fused silica substrates has been studied. Under continuous-wave excitation at 980 nm and nanosecond pulsed excitation at 980 and 1540 nm, the fabricated structures demonstrate room temperature PL with several bands at 410, 523, 546, 658, 800 and 830 nm, corresponding to the 2H9/2 → 4I15/2, 2H11/2 → 4I15/2, 4S3/2 → 4I15/2, 4F9/2→ 4I15/2 and 4I9/2→ 4I15/2 transitions of Er3+ ions. The intensity of erbium UC PL increases when an additional macroporous layer of strontium titanate is used beneath the BaTiO3 xerogel layer. It is also enhanced in BaTiO3 xerogel films codoped with erbium and ytterbium (BaTiO3:(Er,Yb)). For the latter, a redistribution of the intensity of the PL bands is observed depending on the excitation conditions. A multilayer BaTiO3:(Er,Yb)/SiO2 microcavity structure was formed on a fused silica substrate with a cavity mode in the range of 650–680 nm corresponding to one of the UC PL bands of Er3+ ions. The obtained cavity structure annealed at 450 °C provides tuning of the cavity mode by 10 nm in the temperature range from 20 °C to 130 °C. Photonic application of BaTiO3 xerogel structures doped with lanthanides is discussed.

The effect of zirconium on the microstructure, phase composition, and mechanical properties of AlCuYb and AlCuGd alloys was studied. The microstructure of the as-cast alloys did not consist of new intermetallic phases of zirconium with other elements, so the zirconium was fully dissolved in the aluminum matrix. The AlCuYbZr/AlCuGdZr alloys demonstrated higher hardness values compared to the AlCuYb/AlCuGd alloys due to the precipitation of the Al3(Zr,Yb) and Al3(Zr,Gd) phases, which were formed during the homogenization treatment. The AlCuYbZr alloy had a 10–20 MPa higher yield and tensile strength than the AlCuGdZr alloy at the same annealing temperature and time. The AlCuYbZr alloy exhibited good mechanical tensile properties at an annealing temperature of 100 °C for 1 h, with a yield strength of 276 MPa, ultimate tensile strength of 312 MPa, and elongation of 3.1%, while the as-rolled AlCuGdZr alloy had similar mechanical tensile properties, with a yield strength of 279 MPa, ultimate tensile strength of 307 MPa, and elongation of 4.8%. At an annealing temperature of 300 °C for 10 min, The AlCuYbZr and AlCuGdZr alloys showed a good ductility of 10.5% and 8%, respectively, with 207 MPa yield strength for both alloys. AlCuYbZr and AlCuGdZr alloys are a prospective base composition for developing novel high technology heat resistant aluminum alloys.

The influence of homogenization treatment on microstructure evolution of Mg-5.8Zn-0.5Zr-1.0Yb (mass fraction, %) alloy was investigated under different annealing temperatures and holding times. Results indicated a severe dendritic segregation in the as-cast ingot. Zn and Yb segregate remarkably at the grain boundary and Zr appears in the form of precipitates. The Mg-Zn binary eutectic phases and a new ternary phase Mg-Zn-Yb are mainly distributed at dendrite boundaries. After homogenization, most of the eutectic phases dissolve into the matrix, except for a small amount of Mg-Zn-Yb phase. The area fractions of residual secondary phase decrease from 5.54% in the as-cast alloy to 0.59% in the well-homogenized sample. Microhardness test indicates that with the increasing temperature and holding time, microhardness value decreased sharply within the first stage of homogenization and then increased steadily to the local maximum value at 380 ºC and 12 h, followed by a slight reduction. Basing on the comprehensive analysis on microstructure and mechanical properties, the homogenization treatment at 380 ºC for 12 h is preferable.