Effect Of Yb Research Articles

Microstructural evolution and strength enhancement in laser powder bed fusion Al-Mg-Yb-Zr alloys

Al-Mg alloys fabricated by laser powder bed fusion (L-PBF) usually suffer from poor processability and strength response. In this work, the effect of Yb and Zr in Al-Mg alloys was studied using Al-3Mg-0.7Zr and Al-3Mg-0.5Yb-0.7Zr alloys fabricated by L-PBF. The size of average grain along the building direction was measured to be 3.6 μm, of which 94.2 % consisted of equiaxed grains. The formation of Al3(Yb,Zr) phase in the L-PBF was revealed through single-track and multi-track melt pools and the formation of Al3Zr, Al/Al3Yb eutectics, in couple with the L12-Al3(Yb,Zr) phase were found to be responsible for the high-volume fraction of refined equiaxed grains. After aging at 375 ℃ for 14 h, a high-volume fraction L12-Al3(Yb,Zr) (4.5 nm) was formed within the relatively coarse grains (5.8 μm), which showed strong thermal stability and precipitation strengthening. As such, the as-aged Al-3Mg-0.5Yb-0.7Zr alloy can deliver a good combination of strength-ductility, in which ultimate tensile strength (UTS) and elongation (El) are 401 MPa and 15.1 %, respectively.

Upconversion Luminescence Properties of Ho3+/Tm3+/Yb3+ Co-doped NaGd(MO4)2 Prepared by Hydrothermal Method

In this paper, Ho$$^{3+}$$/Tm$$^{3+}$$/Yb$$^{3+}$$-doped NaGd(MO$$_{4})_{2}$$ phosphors were prepared using the hydrothermal method and the effect of Yb$$^{3+}$$ doping amount on the luminescence properties of these phosphor materials was investigated. NaGd(MO$$_{4})_{2}$$ was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and spectral analysis. The results showed that Ho$$^{3+}$$/Tm$$^{3+}$$/Yb$$^{3+}$$-doped NaGd(MO$$_{4})_{2}$$ has tetragonal phase structures, and doping with rare-earth ions decreases the cell parameters of NaGd(MO$$_{4})_{2}$$. NaGd(MO$$_{4})_{2}$$:Ho$$^{3}$$/Tm$$^{3+}$$/Yb$$^{3+}$$ generates blue, green, and red lights at 477, 545, and 659 nm, respectively, under an excitation of 980 nm. The emission of these three lights is called a three-photon process. As the doping ratio of Yb$$^{3+}$$ increases, the colour coordinates of samples gradually approach the white region from the red region, enabling NaGd(MO$$_{4})_{2}$$:0.1Ho/1Tm/20Yb to exhibit white emission. Doping with Yb$$^{3 + }$$ increases the energy transfer and quantum efficiencies of NaGd(MO$$_{4})_{2}$$. When the concentration of Yb$$^{3+}$$ reached 30%, the quantum efficiency of NaGd(MO$$_{4})_{2}$$ reached the maximum value of 188.37%. Overall, NaGd(MO$$_{4})_{2}$$:Ho/Tm/Yb has broad application prospects in the field of white lighting.

Preparation and characterization of SiO2–Al2O3–Na2O–LaF3 upconversion glass-ceramic and its enhancing effect on the performance of photocatalyst

SiO2–Al2O3–Na2O–LaF3 glass-ceramic was prepared by high-temperature melting method and two-step heat treatment schedule. The upconversion performance was obtained under the effect of Yb and Tm. The optimal doping concentration ratio and the photoluminescence mechanism was analyzed. By introducing K+ and Li+ into the system, further optimization of upconversion performance was achieved. To investigate its impact on the efficiency of photocatalysts, glass-ceramic was mixed with photocatalysts to conduct photocatalytic degradation tests. The degradation efficiency of the mixture increased by 22 % compared to the group with only photocatalysts under near-infrared light, and this rate increased by 5.7 % under full spectrum. The first-order kinetic equation was used to fit the degradation rate for kinetic analysis, compared with the k values under near-infrared light, photocatalyst/glass-ceramic (k = 0.0035) > photocatalyst (k = 0.0006), and photocatalyst/glass-ceramic (k = 0.0135) > photocatalyst (k = 0.0124) under full spectrum.

Effects of Yb and Sc co-doping on the thermal properties and CMAS corrosion of garnet-type (Y3-xYbx)(Al5-xScx)O12 ceramics

Thermal barrier coatings with excellent thermal performance and corrosion resistance are essential for improving the performance of aero-engines. In this paper, (Y3-xYbx)(Al5-xScx)O12 (x = 0, 0.1, 0.2, 0.3) thermal barrier coating materials were synthesized by a combination of sol-gel method and ball milling refinement method. The thermal properties of the (Y3-xYbx)(Al5-xScx)O12 ceramics were significantly improved by increasing Yb and Sc doping content. Among designed ceramics, (Y2.8Yb0.2)(Al4.8Sc0.2)O12 (YS-YAG) showed the lowest thermal conductivity (1.58 Wm−1K−1, at 800 °C) and the highest thermal expansion coefficient (10.7 × 10−6 K−1, at 1000 °C). In addition, calcium-magnesium- aluminum -silicate (CMAS) corrosion resistance of YS-YAG was further investigated. It was observed that YS-YAG ceramic effectively prevented CMAS corrosion due to its chemical inertness to CMAS as well as its unique and complex structure. Due to the excellent thermal properties and CMAS corrosion resistance, YS-YAG is considered to be prospective material for thermal barrier coatings.

Effects of Yb2O3 as Stabilizer and Sensitizer on the Luminescence Properties of Cubic ZrO2 Single Crystals

Effects of Yb₂O₃ as Stabilizer and Sensitizer on the Luminescence Properties of Cubic ZrO₂ Single Crystals

Effect of Yb: Fiber laser on surface roughness and wettability of titanium

Background/Aim: In recent years, the role of computer aided design (CAD) and computer aided manufacturing (CAM) in dentistry has increasingly become important. However, the influence of different Yb: fiber laser applications on surface roughness of CAD/CAM implant has rarely been studied. The aim of this study is to investigate the effect of different Yb: fiber laser parameters on the surface roughness of CAD/CAM titanium. Material and Methods: Titanium samples, produced by CAD/CAM, were divided into 11 groups according to laser parameters such as scanning types (ST), application angles (AA) and hatch interval (HI). The surface roughness of CAD/CAM titanium was examined for each group. Wettability contact angles (CA) were also determined. Results: The highest surface roughness (43 mm) value was obtained for Group 10 (three-ways ST, 60o AA, 0.07mm HI). The lowest value (2.77 mm) after control group was obtained for Group 6. Surface roughness values, for Group 3, Group 9 and Group 10 were significantly higher than for the other groups (P= 0.000). In contact angle evaluations, the highest contact angle (144o) was observed in Group 10, while the lowest (95o) was observed in control group. Conclusions: Surface roughness was dependent on mixed effect of the laser application parameters. Three-ways ST, 60o AA, 0.07mm HI provided highest surface roughness and wettability contact angles. The surface roughness values of one-way ST, 0.06 mm HI, two-ways HT, 45o AA and 0.08 mm HI and three-ways ST, 60o AA and 0.07 mm HI were significantly higher than for the other groups (P=0.000).

Effects of welding parameters on the microstructure and mechanical properties of the AA6061 aluminium alloy joined by a Yb: YAG laser beam

In this study, the effects of Yb: YAG laser welding parameters on the microstructure and mechanical properties of AA6061-T4 joints were analysed. Samples without any welding defects such as porosity, melt pool collapse, and hot cracking were produced with different welding parameters. Energetic processing parameters had a significant influence on the fusion zone (FZ) and heat-affected zone (HAZ) microstructure and dimensions, in addition to local and global mechanical properties. The weld bead width increased with increasing power and energy densities and reduced the weld bead tensile properties. High welding travel speed produced a more elongated weld pool and ripples resulted in a ‘V’ shape. A significant quantity of axial heterogeneous nucleation was observed in the FZ centre of these weld beads because of the low-energy density. In contrast, low welding travel speed produced C-shaped ripples and a few axial grain nucleation sites in the FZ. The latter was evidence of a slower solidification rate. Dendrite secondary arm spacing measurements confirmed this hypothesis. It was observed that axial grains in the FZ centre improve the weld bead tensile properties. Compared to the base material (BM), the hardness in the FZ was reduced and identical in the HAZ. The FZ hardness depended on the welding parameters. Digital image correlation (DIC) strain measurements indicated higher deformation near the FZ, but when geometrical defects were removed, the FZ deformed more homogeneously.

Effects of Yb on the electrical and microstructural properties of (Y1-xYbx)Ba2Cu3O7-δ (x = 0 – 1.0) superconductor

Effects of Yb on the electrical and microstructural properties of (Y1-xYbx)Ba2Cu3O7-δ (x = 0 – 1.0) superconductor

Optical and magnetic properties of pure and Er, Yb-doped β-NaYF4 hexagonal plates for biomedical applications

The effects of Yb, Er on structural, optical, magnetic and biocompatibility of β-NaYF4 compounds were examined. The pure and Yb, Er-doped β-NaYF4 compounds were synthesized via simple hydrothermal method. X-ray diffraction analysis revealed the hexagonal crystal structure. The functional group present in the sample was identified by FT-IR analysis. The vibrational bands were analysed by Raman spectroscopy. Electron Microscope images exhibit the hexagonal plate-like morphology. The characteristic absorbance peaks of Yb, Er and host were obtained in UV–VIS–NIR absorbance spectra. The interesting green and enhanced red emission through Photoluminescence spectra of the prepared compounds might be useful for bio-imaging. Pure β-NaYF4 possessed diamagnetic property and Yb, Er-doped β-NaYF4 exhibited paramagnetic property at room temperature. Yb, Er-doped β-NaYF4 was incubated with HeLa cells and assessed cytotoxicity using MTT assay. Hence, Yb, Er-doped β-NaYF4 materials have promising application in cell imaging and bio-separation applications.

Effect of Yb on the Structure and Properties of an Electroconductive Al–Y–Sc Alloy

The influence of ytterbium addition on the phase composition, strengthening upon annealing before and after rolling, and on the electrical conductivity and mechanical properties of the Al–0.2% Y–0.2Sc alloy has been investigated in this work. A dispersed eutectic, in which particles of an intermetallic phase with a size of 100–250 nm are enriched in yttrium and ytterbium, has been revealed in the cast structure apart from the aluminum solid solution. The maximum strengthening of the ingot is achieved after the annealing at 300°C for 3 hours due to the precipitation of Al3M dispersoids. The annealing of deformed sheets at 300°C results in an increase in the hardness and yield strength, which is connected with the initiation of the process of the additional decomposition of the aluminum solid solution. This means that the addition of ytterbium stimulates the heterogeneous nucleation of Al3M dispersoids in the post-rolling annealing process. In this case, according to the international standard for the annealed copper, the electrical conductivity increases with increasing temperature and time of annealing from 54 to 54.9% and to 57.7% after annealing at 200°C and 300°C, respectively.

Improved thermal stability of polyethylene with rare earth trifluoromethanesulfonate

Abstract The thermal degradation of polyethylene (PE) is a free radical chain reaction, in other words, free radicals are the primary cause of combustion and degradation. Discovering proper compounds with radical trapping ability is critical for developing flame retardant PE composites. Herein, we introduced rare earth trifluoromethanesulfonate (RE(OTf) 3 ), with radical trapping ability, into PE. The effects of ytterbium (Yb(OTf) 3 ) and lanthanum (La(OTf) 3 ) on the thermal stability and flammability properties of polyethylene (PE) were investigated systemically. Electron spin resonance (ESR) spectroscopy proved the free radical-trapping ability of La(OTf) 3 and Yb(OTf)3 . The results of thermogravimetric analysis (TG) and differential scanning calorimetry (DSC) showed that Yb(OTf) 3 could improve the thermal stability of PE more significantly compared with La(OTf)3. The flame retardancy of PE/intumescent flame retardant (IFR) composite was improved when 0.4 wt% IFR was substituted by RE(OTf)3. It changed the PE/IFR26 from UL-94 non-rated to V-0. Vertical flame test, limited oxygen index (LOI) and microscale combustion calorimeter (MCC) indicated that the effect of Yb(OTf)3 on the flame retardancy of PE was better than La(OTf)3. The improvement on the thermal stability and flame retardancy of PE is due to the combined action of anion and cation of RE(OTf)3. However, the different effects are attributed to the different reactivity of rare earth elements.

Effect of frustrated exchange interactions and spin-half-impurity on the electronic structure of strongly correlatedNiFe2O4

Spin-polarized density functional calculations, magnetization, and neutron diffraction (ND) measurements are carried out to investigate the magnetic exchange interactions and strong correlation effects in Yb substituted inverse spinel nickel ferrite. In the pristine form, the compound is found to be a mixed insulator under the Zaanen-Sawatzky-Allen classification scheme as it features both charge transfer and Mott insulator mechanisms. Estimation of magnetic exchange couplings reveals that both octahedral-octahedral and octahedral-tetrahedral spin-spin interactions are antiferromagnetic. This is typical of a spin-frustrated triangular lattice with one of the vertices occupied by tetrahedral spins and the remaining two occupied by octahedral spins. However, since the octahedral-tetrahedral interaction is dominant, it leads to a forced parallel alignment of the spins at the octahedral site which is in agreement with the results of ND measurements. The substituent Yb is found to be settled in +3 charge state, as confirmed from the x-ray photoelectron spectroscopy measurements, to behave like a spin-half-impurity carried by the localized ${f}_{z({x}^{2}\ensuremath{-}{y}^{2})}$ orbital. The impurity $f$ spin significantly weakens the antiferromagnetic coupling with the spins at the tetrahedral site, which explains the experimental observation of a decrease in Curie temperature with Yb substitution.

Generation of high-energy femtosecond pulses by use of spectral broadening effects in Yb:YAG thin-disk regenerative amplifiers

As a result of experimentally verified simulations of Yb:YAG regenerative amplifiers utilizing spectral broadening effects due to self-phase modulation, we provide a map for the optimized choice of initial chirp and internal group-delay dispersion (GDD) within the amplifier. We show that the shortest pulse durations can be obtained with negative internal GDD, being, however, limited by the damage threshold of the optical components due to increased peak powers and by a breakup of pulses comparable to the propagation of higher-order solitons. We propose that by usage of increasing amounts of positive internal GDD, along with a corresponding amount of negative initial GDD, the obtainable peak powers after compression can be scaled far beyond the usual gain-bandwidth limitation.

Yielding of cement-mixed gravelly soil affected by viscous property, ageing and damage

The yielding of compacted moist cement-mixed gravelly (CMG) soil, subjected to arbitrary loading histories with two stress variables, is studied by means of non-standard drained triaxial compression tests. A non-linear three-component model is modified to describe the elasto-viscoplastic property affected by ageing and shear yielding-associated damage. The development of the inviscid yield locus (YL) is formulated based on the interactive double-yielding mechanism that comprises (i) the bounding mechanism controlled by “inviscid YL, YB” and (ii) the frictional mechanism controlled by “inviscid YL, YF”. Each inviscid YL is determined as an inner envelope of a given set of YB and YF that have developed by ageing and shear yielding and have been affected by damage. As the inviscid YL approaches the peak strength line, the shape changes in association with a decrease in the effect of YB and an increase in the effect of YF. The size and shape of the respective YLs in total stresses (i.e., measured effective stresses) are different from those of the corresponding inviscid YLs due to the viscous effects. The total stress–strain relation for a given loading history is obtained by accounting for the viscous effects from the inviscid stress–strain relation, which is obtained from the basic inviscid stress–strain relation accounting for the effects of ageing and damage. It is shown that this model can properly simulate the development of YL for a wide variety of loading histories applied along various stress paths.

Multifunctional nanoheater based on NaGdF4:Yb3+, Er3+ upconversion nanoparticles.

Upconversion nanoparticles (UCNPs) provide an ideal platform for achieving multifunction, such as multimodal imaging, sensing, therapy, etc., mainly by combining with other nanomaterials to construct complicated heterogeneous nanostructures. Multifunctional integration on a simple single-phase structure still is an open question and poses a big challenge. Here we show that small-sized NaGdF(4):Yb(3), Er(3+) UCNPs (~7.5 nm) can simultaneously possess upconversion luminescence (UCL), temperature sensing, paramagnetic and photothermal conversion properties, endowing them great potential for photothermal treatments with real-time imaging and temperature monitoring. Effects of Yb(3+) concentrations, nanoparticle sizes and core/shell structures on the light-to-heat conversion capability of UCNPs were also investigated, and the results were discussed on the basis of the variation in absorption rates and non-radiative relaxation probabilities of UCNPs. There is a competition between UCL and light-to-heat conversion processes. Higher UCL efficiency and enhanced photothermal conversion properties can be realized on UCNPs with the active-core/active-shell structure due to enhanced absorption rates.

Thermal effects in Yb:YAG single-crystal thin-rod amplifier

This work presents a new design for the laser gain module based on a ytterbium-doped yttrium aluminum garnet (Yb:YAG) single-crystal thin rod. Thermal effects (temperature, phase, and polarization distortion of laser radiation) and small signal gain are investigated both experimentally and theoretically. We then analyzed the influence of thermal effects and amplified spontaneous emission on the power scaling of the laser based on the gain module. A small signal gain as high as 3.3 per pass was experimentally achieved.

Abstract 3433: Identification of potential salivary response biomarkers in subjects practicing yogic breathing

Abstract Yogic Breathing (YB; Pranayama) is a form of Yoga technique practiced since ancient times for healthy living. In the United States, the practice of Yoga has markedly increased in recent years. Recent data suggest that adjunctive Yoga in cancer patients may help patients with symptom management. Whereas there are data on Asana (Postures) that involve physical movements in cancer patients, there are limited data on YB. Considering the ease of practice when compared to Asana, YB might benefit patients who are already physically overwhelmed with symptom burden. Current data measure the outcomes of Yoga using subjective measures, but biomarkers in an easily accessible biospecimen might provide key information as to the effects of YB among practitioners. We hypothesized that YB stimulates alterations in the salivary biomarker expression. We conducted an Institutional Review Board approved pilot randomized controlled trial in 20 subjects (n = 10 in each group) to compare the salivary expression of biomarkers between a 20 min YB group vs. Attention Control (AC) group. The YB group performed two exercises (Pranava Pranayama, and Thirumoolar Pranayama) each for 10 min, and the AC group read a scientific article for the same amount of time. Tandem Mass Spectrometric (LC-LC-MS-MS), Multiplex, and Western blot analysis showed the differential expression of 22 salivary proteins associated with immune response, stress and cancer. As compared with the AC group, YB increased Deleted in Malignant Brain Tumor 1 (DMBT1) as early as 5 min and maintained significantly high levels in all time points tested. In contrast, YB reduced IL-1beta (at 10, 15 and 20 min) and IL-8 levels (at 5, 10, 15 and 20 min) in participants when compared to AC controls. Further analysis of salivary lipidomic profiles demonstrated marginal reductions in sphingosine and sphingosine-1-phosphate levels in YB group. Collectively, our data provide the first evidence that YB could alter salivary biomarkers associated with cancer, inflammation, and stress. These markers may be useful to evaluate symptom management via stress reduction and immune regulation. Citation Format: Sundaravadivel Balasubramanian, Michael G. Janech, Graham W. Warren. Identification of potential salivary response biomarkers in subjects practicing yogic breathing. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3433. doi:10.1158/1538-7445.AM2015-3433

Effect of Yb^3+ on the upconversion luminescence of Tm^3+/Yb^3+ co-doped La_2O_3-TiO_2-ZrO_2 glasses

Containerless processing has been used to prepare Tm3+/Yb3+ co-doped La2O3-TiO2-ZrO2 (LTZ) glasses with intense blue emission. The effects of Yb3+ ions on the thermal stability and upconversion luminescence of as-prepared LTZ glasses and glass-ceramics have been studied. Yb3+ ions perform negative effect on the thermal stability of glasses. As Yb3+ increases, the emissions can be enhanced by improving energy transfer from Yb3+ to Tm3+ and reducing energy loss. A model is proposed to discuss the effects of active ions, sensitizers, and hosts on the upconversion luminescence process. Moreover, the refractive index value and Abbe number of glasses are 2.261 and 20.7, indicating excellent optical properties.

Enhanced emission of 2.86 μm from diode-pumped Ho(3+)/Yb(3+)-codoped PbF(2) crystal.

A novel Ho(3+)Yb(3+)-codoped PbF(2) mid-IR laser crystal was successfully grown and analyzed. Enhanced emission at 2.86 μm was observed from the crystal under excitation of a common 970 nm laser diode for the first time. The effect of Yb(3+) codoping on the 2.86 μm photoluminescence of Ho(3+) was investigated. In comparison to Ho(3+)-singly doped PbF(2) crystal, the Ho(3+)/Yb(3+)-codoped PbF(2) crystal possessed comparable quantum efficiency (88.8%), and fluorescence branching ratio (20.52%) along with a larger calculated emission cross section (1.90×10(-20) cm(2)) corresponding to the laser transition (5)I(6)→(5)I(7) of Ho(3+). It was found that the introduced Yb(3+) enhanced the 2.86 μm emission by depopulating the Ho(3+):(5)I(7) level. The energy transfer (ET) efficiency from Yb(3+):(2)F(5/2) to Ho(3+):(5)I(6) is as high as 96.7%, indicating that Yb(3+) ion is an effective sensitizer for Ho(3+) ion in PbF(2) crystal. These results suggest that Ho(3+)/Yb(3+)-codoped PbF(2) crystal may become an attractive host for developing solid state lasers at around 2.86 μm under a conventional 970 nm LD pump.

Threshold characteristics analysis of a uniformly side-pumped Yb3+-doped gain-guided and index-antiguided fiber laser

Abstract The improved rate equations with additional leakage losses of signal light for a uniformly side-pumped Yb 3+ -doped gain-guided and index-antiguided fiber laser are established. An exact analytical expression of threshold pump power is obtained. Then the effects of Yb 3+ concentration, fiber length, core radius and mirror reflectivity on threshold pump power are discussed in detail, separately. The method of designing the fiber parameters is described while maintaining single mode oscillation, such as R 1 =1, R 2 =0.75, a =85 μm, L =10 cm, N =5×10 20 cm −3 , and threshold power is 6.3 W. Compared with end-pumped scheme, the doped concentration and length of the fiber used in side-pumped scheme can be both larger. The analytical solution was easy to calculate and showed distinct results for the optimal design of the fiber laser.