Increase In Tin Concentration Research Articles

Resonant impurity level of Ni in the valence band of Pb1−xSnxTe alloys

The phase and elemental compositions and galvanomagnetic properties (4.2 K ≤ T ≤ 300 K, B ≤ 0.07 T) of samples from a single-crystal Pb1−x−ySnxNiyTe ingot (x = 0.08, y = 0.01) synthesized by the Bridgman–Stockbarger method were studied. Microscopic inclusions enriched in nickel were found. It is shown that in the main phase, the tin concentration increases exponentially along the ingot (x = 0.06–0.165), while the concentration of nickel impurity does not exceed 0.4 mol %. A significant increase in the concentration of holes along the ingot and an abnormal increase in the Hall coefficient with increasing temperature were found; both are due to the pinning of the Fermi level by the resonant nickel level located in the valence band. The dependences of the hole concentration and of the Fermi energy at T = 4.2 K on the tin concentration in alloys are calculated using the two-band Kane dispersion law. A qualitative model of electronic structure rearrangement is proposed. The model takes into account the movement of the nickel level into the depth of the valence band with an increase in tin concentration and the redistribution of electrons between the valence band and the level. The energy position of the nickel level and the speed of its movement relative to the top of the valence band with an increase in the tin content in Pb1−xSnxTe alloys are estimated.

The role of Sn–Fe co-doping on the atomic structure, phase transformation and antibacterial activity of TiO2 nanoparticles

Here, we studied the influence of Sn and Fe co-doping on the phase transformation and antibacterial properties of TiO2 nanoparticles. Different molar percent, including 0.6, 1.2, 2.4, and 4.8 mol%, of Fe and Sn were doped into the TiO2 nanoparticles and then the sample’s bactericidal properties, morphology, and crystal structure were studied. The antibacterial assessment’s results demonstrate excellent antibacterial properties of doped samples against Gram-negative Escherichia coli bacteria strain. Results showed that samples with the high concentration of Sn dopant showed maximum inhibition to the growth of bacteria. By increasing the concentration of Sn from 0.6 mol% to 4.8 mol%, the size of inhibition zone increased from 12 mm to 20 mm, respectively. But by rising the amount of Fe dopant in the presence of 0.6 mol% Sn antibacterial properties of nanoparticles did not change significantly. Such trend also observed in the specific surface area of the synthesized samples. Sn doping has more effect on the specific surface area in comparison to Fe doping. With an increase in tin concentration from 0.6 mol% to 4.8 mol%, the specific surface increased from 61.11 to 140.40 g.m-2, while for doped samples with the same mol% of Fe, it was only increased from 61.11 to 126.7 g.m-2.

Effect of sulfurization on the properties of Cu2ZnSnS4 thin films deposited using chemical spray pyrolysis over ITO substrates

Cu2ZnSnS4 thin films with different tin concentration are deposited over ITO coated glass substrates using chemical spray pyrolysis technique, by adjusting [Sn][Zn] ratio as 0.7, 1 and 1.3 in the precursor solution. As prepared films are subjected to sulfurization at a temperature of 500°C for 15min and its effect on the structure and composition of the films is studied. Sulfurization is carried out under non-vacuum condition inside the spray pyrolysis chamber making it compatible with the deposition technique. Pristine and sulfurized films are analysed using X-ray photoelectron spectroscopy, X-ray diffraction, Raman spectroscopy, UV–Vis–NIR spectroscopy and scanning electron microscopy. X-ray diffraction and Raman spectroscopy suggest the formation of Cu2ZnSnS4 and other binary compounds in the pristine films. Analysis of the sulfurized films indicates that the sulfurization process has brought about a significant change in the composition of the films while improving its crystallinity considerably. Compositional analysis using X-ray photoelectron spectroscopy reveals that substantial amount of indium from the underlying ITO has diffused into the film after sulfurization. However, it is observed that increase in concentration of tin in the film limits the diffusion of indium. Scanning electron microscopic images show the improvement in morphology of the films after sulfurization.

Modeling of some physicochemical properties in the liquid Au–Bi–Sn alloys relevant for Pb-free soldering

In this paper, some geometrical models such as Kohler, Muggianu, Toop, and Hillert have been used to estimate the molar volume of Au–Bi–Sn ternary systems based on the data of sub-binary systems over a wide temperature range (673–973[Formula: see text]K). The density of Au–Bi–Sn alloys was calculated from the calculated molar volume and using theoretical equation along three cross-sections [Formula: see text]/[Formula: see text]/2, 1/1 and 2/1. In addition, the viscosity of Au–Bi–Sn alloys was calculated by using Seetharaman–Sichen equation over a wide temperature range (673–1273[Formula: see text]K). The density of these alloys show linear dependence on temperature for all investigated compositions, while the molar volumes increase with increasing temperature and Sn compositions. The results show, as a function of temperature, that the increase in concentration of tin influences the viscosity of the Au–Bi–Sn alloys. The calculated values of density of Au–Bi–Sn alloys are compared with the experimental values reported in the literature, and a good agreement was observed.

Higher Toxicity of Dibutyltin and Poly-L-Lactide with a Large Amount of Tin but Lower Toxicity of Poly-L-Lactide of Synthetic Artificial Dura Mater Exhibited on Murine Astrocyte Cell Line

Neurotoxicities of dibutyltin (DBT), tin(II) octylate (OT), poly-L-lactides (PLLA, molecular weight [MW]=5000, PLLA 5000), PLLA without tin (MW=3000, PLLA 3000), PLLA with a large amount (590 ppm) of tin (S3), poly(glycolic acid-co-epsilon-caprolactone) oligomer (MW=6200, PGC oligomer), and poly(L-lactic acid-co-glycolic acid-co-epsilon-caprolactone) oligomer (MW=6400, PLGC oligomer) related to artificial dura mater were examined using the murine astrocyte cell line, CRL-2534. The indices were cell viability, glutamate concentration in the cell supernatant, and cell proliferation. Lower cell viability was observed among cells exposed to 0.5 microM DBT or 10 microg/ml of S3. There were no differences in cell viability of astrocytes exposed to OT, PLLA 5000, PLLA 3000, PGC oligomer, or PLGC oligomer. Mean glutamate concentration in the supernatant of cells exposed to 0.25 muM DBT was higher than that of the control after 2 h incubation. Lower mean concentration of glutamate in the supernatant of cells exposed to 5 microg/ml of S3 was observed after 2 h incubation. Cells exposed to 50 microg/ml of PGC oligomer had a higher mean concentration of glutamate in the supernatant. OT only inhibited cell proliferation at 100 microM. Proliferation of cells exposed to 0.25 microM or 0.5 microM DBT was inhibited, as was that of cells exposed to 100 microM OT, 50 microg/ml PLLA 5000, 50 microg/ml PLLA 3000, and 5 microg/ml S3, 5 d and 7 d after exposure. Although DBT does not reach levels that induced neurotoxicity in artificial dura mater, these results suggest that DBT is neurotoxic and PLLA toxicity increases with the increase in tin concentration.

Far-infrared, Raman spectroscopy, and microwave dielectric properties of La(Mg0.5Ti(0.5−x)Snx)O3 ceramics

La ( Mg 0.5 Ti ( 0.5 − x ) Sn x ) O 3 perovskite ceramics with composition (x=0.0−0.5) are prepared by the solid state reaction method. The ceramics are characterized by x-ray diffraction, far-infrared reflectance, Raman spectroscopy, and microwave dielectric properties. The symmetry of ceramics is monoclinic with P21/n space group. Intrinsic dielectric constant and loss are estimated by fitting reflectance to the four-parameter semiquantum model. Transverse optic phonon mode strengths and average phonon damping are calculated. The modes corresponding to B-site ordering are identified in Raman spectra and the A1g mode of La(MgTi)0.5O3 is analyzed by assuming two merging modes. The variation of long-range order is correlated with full width half maximum of the A1g mode. Microwave measurements are carried out in the frequency range of 8–10 GHz. The dielectric constant (ε′) is found to gradually decrease from 28.4 to 19.7 with an increase in tin concentration, whereas the temperature coefficient of resonant frequency (τf) decreases from −68 to −84 ppm/°C. The product of the quality factor and resonant frequency (Q×f) obtained for La(MgTi)0.5O3 is 55,000 GHz, that decreases to 46,000 for x=0.25 composition and then increases to 63,000 GHz for La(MgSn)0.5O3.

Oxidaiton of tin/II/ in air-kept hydrochloric acid solutions

An air-storage stability of tin/II/ chloride solution was studied by voltammetric and spectrophotometric methods. The chosen concentration range was due to the problems of the kits preparation for a99mTc generator. The rate of oxidation of tin/II/ in the range of 0.04–12.5 mg.ml−1 was shown to decrease with an increase in tin concentration. According to the obtained results one can determine maximal storage time for the correct practical use.

Granite magmatism and tin-tungsten metallogenesis in the Kuantan-Dungun area, Malaysia

The Kuantan-Dungun area (6000 km 2) is an important tin district which produced about 40 % of all tin mined in the Eastern Granite Province of Peninsular Malaysia. It is the most important wolframite-producing district in Malaysia. The largest underground tin mine of Malaysia (Sungei Lembing) is also located in this area. The granitoids that occupy about 30% of the area have a Permian age (240 - 275 Ma) except for a Triassic stock at Paka near Dungun (220 Ma). The composition of the granitoids ranges from gabbro to biotite granite (monzogranite). The largest part is occupied by biotite granite which exhibits characteristics of both S-type granite derived from a sedimentary source rock and I-type granite derived from an igneous protolith. Hornblende-biotite granite (to granodiorite) and gabbro (to quartz diorite) are subordi­ nate. The basic to intermediate rocks have affinities to tholeiitic magma and are not genetically linked to the granites by fractional crystallization. But the gabbroic rocks and the granites may have had a co=on heat source. Only in hydrothermally altered portions, the Kuantan-Dungun granites show ele­ vated Sn concentrations (up to 34 ppm Sn). The tin concentrations in unaltered rocks are low (averaging 3 ppm Sn). The Kuantan-Dungun granites have in common with other granites in the Eastern Province, tin concentrations that seem to be unrelated to the dif­ ferentiation stage, i.e. tin is a decoupled element. Both the low tin concentrations and the decoupled behavior of tin are unusual features of granites associated with tin deposits. The metallogenesis of tin in the wolframite-cassiterite area of Kuantan-Dungun is different from that in cassiterite-dominated S-type granite systems with very subordinate wolframite in the Main Range, of which the BujangMelaka pluton in the Kinta Valley is a typical example. The Main Range batholith, in general , and the Bujang Melaka pluton, in particular, show a significant increase in tin concentration with increasing degree of magmatic differentiation, i.e. tin is much higher in late-stage differentiates than in less evolved rocks. But for the Kuantan-Dungun granites, the distribution coefficient of tin between melt and solid must have been near 1 during most of the crystallization history of the magma. Tin enrichment did not take place until the residual fluids separated from the crystallizing magma.

Magnetic properties of PbTe and Pb1-xSnxTe.

The importance of various contributing mechanisms to the magnetic susceptibility \ensuremath{\chi} and Knight shift K of ${\mathrm{Pb}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{Sn}}_{\mathrm{x}}$Te is analyzed using a k\ensuremath{\cdot}\ensuremath{\pi} perturbation theory. It is found that the spin contributions, ${\ensuremath{\chi}}_{s}$ and ${K}_{s}$, are the dominant terms. However, with increase in carrier concentration, the strengths of ${\ensuremath{\chi}}_{\mathrm{so}}$ and ${K}_{\mathrm{so}}$ increase, and become of the same order as ${\ensuremath{\chi}}_{s}$ and ${K}_{s}$, respectively. While ${\ensuremath{\chi}}_{o}$ is of the same order as ${\ensuremath{\chi}}_{s}$, but with a negative sign, ${K}_{o}$ is three orders less than ${K}_{s}$. It is also found that electron-electron exchange enhancement increases with increase in the carrier density. However, both \ensuremath{\chi} and K remain virtually unaffected by electron-electron interaction because the maximum carrier density considered is about four orders less than the metallic density where the exchange enhancement is significant. With alloying, i.e., with increase in tin concentration, both \ensuremath{\chi} and K decrease for a fixed carrier density, with reference to the corresponding values in PbTe. This and other features considered are in overall agreement with the experimental results.