Binary Pb Research Articles

Temperature dependence of piezoelectric properties of the binary Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystals prepared by continuous feeding Bridgeman method

We have confirmed that the temperature dependence of the dielectric constant and piezoelectric charge constant of length-extensional mode d 31 of AC poled (ACP) Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 single crystals (SC) is 15 °C higher than that of DC poled (DCP) SC. The ACP SC, grown by the continuous feeding Bridgman process exhibited a d 31 of −2500 pC N−1 at 88 °C and maintained over −700 pC N−1 up to 105 °C. In comparison, the DCP SC showed a d 31 of −1500 pC N−1 at 88 °C and only maintained −700 pC N−1 up to 90 °C. In addition, low frequency constant N 31 of 560 Hz·m at 25 °C and 390 Hz·m at 88 °C of the ACP SC showed 25% and 37% lower than those of DCP SC. The ACP SC outperforms DCP SC not only in piezoelectric properties at room temperature but also heat resistance and this information is important for future ultrasound devices design.

A versatile study of single and binary removals of Pb(II) and Cd(II) ions from aqueous solutions using pine cone as biosorbent

A naturally occurring biosorbent (pine cone) was utilized to remove single and binary Pb(II) and Cd(II) ions from aqueous solutions. The biosorbent has been examined using ATR-IR, SEM, XRD, and pHpzc. The impacts of process factors such as contact time, pH value, biosorbent dosage, initial concentration, and medium temperature on the biosorption of Pb(II) and Cd(II) ions were researched. Langmuir and Freundlich's isotherms were implemented to describe the equilibrium process. At the most favorable condition for each metal, the Langmuir isotherm yielded a maximum loading capacity (qmax) of 43.47 mg/g for Pb(II) and 32.89 mg/g for Cd(II). The highest biosorption was reached with a single system and then reduced in the presence of coexisting ions in the mixtures under optimal conditions. Desorption studies show that 0.5 M HNO3 is the most effective way to remove heavy metals from a biosorbent loaded with metal ions. Thermodynamic parameters (ΔH°, ΔS°, and ΔG°) calculated from temperature data indicate that the biosorption mechanism is exothermic for Pb(II) and endothermic for Cd(II), spontaneous and favorable.

Pb isotopic fingerprinting of uranium pollution: New insight on uranium transport in stream-river sediments

Uranium mill tailings (UMT) present a significant environmental concern due to high levels of radioactive and toxic elements, including uranium (U), thorium (Th), and lead (Pb), which can pose serious health risks to aquatic ecosystems. While Pb isotopic tracers have been widely utilized in environmental studies to identify elemental sources and geological processes, their application in U geochemistry remains relatively limited. In this study, we investigate the distribution and migration of U in stream-river sediments surrounding a decommissioned U hydrometallurgical area, employing Pb isotopes as tracers. Our findings reveal significant enrichment and ecological risk of U, Pb, and Th in the sediments. Uranium predominantly associates with quartz and silicate minerals, and its dispersion process is influenced by continuous leaching and precipitation cycles of typical U-bearing minerals. Furthermore, we establish a compelling positive relationship (r2 = 0.97) between 208Pb/207Pb and 206Pb/207Pb in the stream-river sediments and sediment derived from UMT. Application of a binary Pb mixing model indicates that anthropogenic hydrometallurgical activities contribute to 2.5–62.7% of the stream-river sediments. Notably, these values are lower than the 6.6–89.6% recorded about 10 years ago, prior to the decommissioning of the U hydrometallurgical activity. Our results underscore the continued risk of U pollution dispersion even after decommission, highlighting the long-term environmental impact of UMT.

Novel pyroelectric single crystals PIN-PMN-PT and their applications for NDIR gas detectors

Ternary manganese-doped (1−x−y)Pb(In1/2Nb1/2)O3-xPb(Mg1/3Nb2/3)O3-yPbTiO3 (Mn-doped PIN-PMN-PT) single crystals have demonstrated remarkable pyroelectric properties alongside enhanced temperature stability. These attributes hold substantial promise for the advancement of high precision nondispersive IR (NDIR) applications. In this study, Mn-doped 0.21Pb(In1/2Nb1/2)O3-0.49Pb(Mg1/3Nb2/3)O3-0.30PbTiO3 single crystals were introduced and carefully investigated. A compensated structure of pyroelectric IR detector based on Mn-doped PIN-PMN-PT single crystal was designed and fabricated, and a CO2 gas concentration monitoring module was built. Results showed that Mn-doped PIN-PMN-PT single crystals exhibit high pyroelectric coefficient, and better thermal stability than binary (1−x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 system. The compensated pyroelectric IR detectors using Mn-doped PIN-PMN-PT single crystals as element chips showcase a performance that is approximately fourfold higher than that of commercial LiTaO3 pyroelectric detectors. The NDIR CO2 gas sensor module was assembled and exhibited remarkable accuracy along with an impressively low minimum detection concentration. These outcomes underscores its substantial potential for practical utilization in gas monitoring applications.

Remediation of Pb(II) and Cd(II) in polluted waters with calcium thioglycolate–modified straw biochar

The pollution of water bodies by heavy metals (HMs) such as Pb(II) and Cd(II) poses a serious environmental risk. Herein, rice straw biochar (RBC) modified with calcium thioglycolate was used to remove Pb(II) and Cd(II) from aqueous solutions. The adsorption performance of the modified biochar was investigated via adsorption kinetics and isotherm model fitting. Furthermore, scanning electron microscopy (SEM), X-ray energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) were used to elucidate the modification and adsorption mechanisms. The results showed that the modification process loaded sulfur-containing functional groups, calcium carbonate, and calcium oxalate crystals on the biochar surface, considerably enhancing its complexation performance and ion-exchange capacity. The equilibrium adsorption amounts for Pb(II) and Cd(II) reached 124.92 and 65.44 mg g−1 in unary systems, respectively; they reached 121.34 and 39.43 mg g−1 in a binary Pb(II) and Cd(II), respectively. Moreover, the optimal adsorption conditions were as follows: pH = 6, temperature = 25 °C, dosage = 0.8 g L−1, and contact time = 2 h. In the binary Pb(II) and Cd(II) system, the adsorption process obeyed the Langmuir competitive adsorption model, which means that one adsorption site on the modified biochar was effective for only one heavy-metal ion, and the modified biochar was more selective for Pb(II) than for Cd(II). The adsorption mechanism, which was dominated by chemisorption, mainly involved complexation, precipitation, ion exchange, and cation-π interactions. Meanwhile, adsorption and desorption experiments indicated that the modified biochar exhibited satisfactory recycling performance, demonstrating its feasibility as an inexpensive and efficient heavy-metal adsorbent for polluted water.

Naples yellow: Experimental re-working of historical recipes and the influence of the glazing process in the in situ analysis of historical artwork

Naples yellow was widely used across different types of artwork. Technical studies identified a binary Pb–Sb type as well as modified ternary variants with either zinc or tin in the structure. Although these variants were the object of previous experimental studies, a better understanding of the impact of the glazing procedure on the chromatic, chemical and crystallographic characteristics of the pigment is still lacking. In this work, several historical Naples yellow recipes were re-worked and subsequently applied and fired on test tiles, over a white glaze. The results show that the interaction between pigment and glaze produces important modifications to the colour, chemistry and structure of the pigment. Such modifications will strongly impact the reconstruction of historical recipes, with major consequences for identifying Naples yellow variants on artwork and investigating artistic practices.

The influence of Pb content on the interfacial free energy of solid Sn in eutectic Pb–Sn liquid mixtures using molecular dynamics simulations

ABSTRACT The solid–liquid interfacial free energy (γ) for binary Pb–Sn systems at different concentrations and crystal orientations is calculated using molecular dynamics (MD) simulation that employs a modified-embedded atom method interatomic potential. First, the solid–liquid interface is constructed in MD simulations according to its calculated phase diagram. Then, the capillary fluctuation method (CFM) is employed for the calculation of the solid–liquid interfacial stiffness. A novel systematic approach is proposed that eliminates the error in the linear approximation of the CFM. The results show that orientation of the solid Sn crystal does not have a significant influence on the value of the stiffness, which explains the experimentally observed spherical shape of Sn particles in eutectic liquid Pb–Sn mixtures. The calculated γ for pure Sn is in good agreement with experimental counterparts. In addition, this study finds that γ slightly increases with increasing the concentration of Pb in the eutectic liquid Pb–Sn mixture, which agrees with available experimental data.

Heavy metals and Pb isotopes in a marine sediment core record environmental changes and anthropogenic activities in the Pearl River Delta over a century

Heavy metal accumulation in marine sediments is associated with changes in both the natural environment and human activities. This study used heavy metals and Pb isotopes in a precisely dated (by 210Pb and 137Cs) sediment core from the Macao Sea to reconstruct the historical changes in anthropogenic activities and the environment in the western Pearl River Estuary (PRE). The distribution of heavy metals in the sediment core could be divided into four stages (pre-1950, 1950–1976, 1976–2000, and post-2000), which corresponded to the changes in anthropogenic activities and environment of the Pearl River Delta during the past 100 years. The contribution of anthropogenic metals (Pb and Zn) in the sediments increased gradually over time. However, the concentrations, enrichment factors, and fluxes of heavy metals in the sediments all displayed a downward trend since 2010, revealing a decline in metal pollutant input due to strict emission reduction policies implemented in the last decade. The Pb isotopes in the sediments showed a similar trajectory to the heavy metals, reflecting the changes in Pb sources in the sediments at different stages. Based on a binary Pb isotope mixing model, the calculated proportions of anthropogenic and natural Pb in the sediments were 0–50.9% (mean 15.9%) and 49.1–100% (mean 84.1%), respectively, suggesting that the Pb in the PRE sediments is mainly controlled by natural sources.

Enhancing Electromechanical Properties of Pb(Sc1/2Nb1/2)O3‐PbZrO3‐PbTiO3 Piezoelectric Ceramics via Templated Grain Growth

AbstractRelaxor‐PbTiO3‐based ternary ferroelectric solid‐solution ceramics with high Curie temperature end members are effective to achieve broader usage temperature range and drive field stability, meanwhile with comparable piezoelectric responses to binary Pb(Mg1/3Nb2/3)O3‐PbTiO3 (PMN‐PT). Templated grain growth is viable alternative to crystal growth that uses templates to induce crystal orientation along a specific direction, thus enhancing the piezoelectric response. In this research, perovskite Pb(Sc1/2Nb1/2)O3‐PbZrO3‐PbTiO3 (PSN‐PZ‐PT) system with varying components is developed to determine the morphotropic phase boundary; together with the texturing characteristics, a high piezoelectric response with broad temperature usage range is expected. 37.5PSN‐20PZ‐42.5PT exhibits enhanced piezoelectric d33 of 530 pC N−1 and strain level of 0.20% at 20 kV cm−1, while retaining a high Curie temperature of 309 °C. Of particular interest is that a high piezoelectric voltage coefficient g33, totaling 56 × 10−3 Vm N−1 can be achieved in this composition, leading to a high figure of merit, (d33 × g33)/tan δ, of 5.8 × 10−10 m2 N−1, one order higher than that of PMN‐PT textured counterpart, being potential for energy harvesting and hydrophone applications.

Heavy metal(loid) and Pb isotope compositions of black shale weathering profiles on the northern Yangtze Platform: insights into geochemical behavior, contamination assessment, and source apportionment.

Heavy metal(loid) (Cd, Co, Cr, Ni, Cu, Zn, Pb, V, Tl, and As) and Pb isotope compositions of two black shale weathering profiles were determined to investigate the geochemical behaviors of these toxic elements during black shale weathering and the heavy metal(loid) contamination and source apportionment of Pb in black shale-associated soils. Black shale has higher heavy metal(loid) concentrations than the upper continental crust and the worldwide average shale. In contrast, the surface soils have much higher heavy metal(loid) concentrations than the profile soils. The heavy metal(loid) concentrations in black shale-associated soils are higher than the Chinese and worldwide soil background values, except for Co and Pb. Black shale-associated soils, especially the surface soils, have higher average concentrations of As, Cd, Cr, Ni, Cu, and Zn than Chinese, Dutch, and Canadian soil guidelines. The enrichment factor (EF) and geoaccumulation index (Igeo) values indicate various degrees of heavy metal(loid) contamination in these soils, particularly for the heavy metals Cd, Tl, and V and metalloid As. Co and Pb contamination in these soils is not a current concern. According to the mass transfer coefficient (τTa,j) values, Cd, Co, Ni, and Zn show overall losses, and other metals (Cr, Cu, Pb, and V) exhibit different behavior in the studied black shale weathering profiles. Based on a simple binary Pb isotopic mixing model, black shale is the dominant contributor to the Pb in black shale-associated soils (70.5-91.1% to profile soils and 81.2-88.8% to surface soils), and vehicle exhaust contributes less (8.9-29.5%) to the Pb in profile soils. Vehicle exhaust can exert an impact on the Pb isotopic evolution at depth intervals of 60-80 cm below the soil surface.

Solid-Phase Low-Temperature Evolution of the Binary Pb–Au System: Via Contact Interactions to Intermetallic Compounds, through the Destructurization to a New Multielemental State

The paper presents the results of the long-term experiment on the solid-phase transformation of the Au–Pb metallic system which takes place at room and cryogenic temperatures. It is found that the solid-phase contact interactions between lead and gold lead to the formation of the Pb + AuPb3 eutectoid. The mass transfer and the phase formation are due to the lead extrusion along the percolation channels that form as a result of the substructural destruction of gold. No reaction layer forms at the boundary of the contacting metals. The decomposition of the solid solutions based on intermetallics AuPb3 occurs through the process of the destructurization of the material into nanoparticles, the displacement of impurity atoms from the bulk to the boundaries, the integration and ordering of separated components of the solid solution. The decomposition of the AuPb3 intermetallic compound leads to the formation of AuPb2 and the phases of variable compositions, and, then, pure components Au + Pb. The decomposition occurs through the stage of fast growth of lead crystals accompanying by the formation of loose gold nanoparticles that gradually take a faceting. The results of these studies can be useful for solution of problems of designing multicomponent metallic materials with an evolution prediction of their structure–phase transformations under the service conditions.

An experimental study about the effects of phosphorus loading in river sediment on the transport of lead and cadmium at sediment-water interface

Phosphorus (P) in the river sediment plays an important role in the fate and transport of heavy metals at sediment-water interface of the aquatic eutrophication environment. To explicate the effect of P loading, the sediments with different P contents were employed in this study to experimentally investigate the adsorption/desorption of Pb2+ and Cd2+ and the releasing behavior of P during the adsorption/desorption processes. Results illustrated a strong affinity between Pb2+ ions and the P-containing sediments in both single Pb and binary Pb + Cd systems. In single-metal systems, the Pb2+ adsorption capacities of all types of sediments (15.04–19.44 mg g−1) were higher than those for Cd2+ (4.68–5.56 mg g−1). While in binary-metal systems, the Pb2+ adsorption was slightly influenced by the coexisting Cd2+, but the Cd2+ adsorption capacities were decreased by over 5 times. Moreover, the adsorption amount and retention ability of Pb2+ on sediment were enhanced by increasing content of P in the sediment. Meanwhile, the releasing of P was also closely depended and significantly inhibited by the Pb2+ attached on the sediment. The P release amounts during the desorption processes of Pb- and Pb + Cd-loaded sediments were over 50 times lower than those from the raw sediments (sediments without heavy metals adsorbed), but the values decreased by a factor of two for the single Cd-loaded sediments. Furthermore, the results of X-ray photoelectron spectroscopy indicated the crucial role of P loading in Pb transport in the sediment and overlaying water. The findings in this study showed important implications for the transport of heavy metals and P at the sediment-water interface and offered new insights for further explicating the mechanisms of secondary pollution caused by heavy metals and P in aquatic eutrophication environment.

Solidification Morphology and Bifurcation Predictions with the Maximum Entropy Production Rate Model

The use of the principle of maximum entropy generation per unit volume is a new approach in materials science that has implications for understanding the morphological evolution during solid–liquid interface growth, including bifurcations with or without diffuseness. A review based on a pre-publication arXiv preprint is first presented. A detailed comparison with experimental observations indicates that the Maximum Entropy Production Rate-density model (MEPR) can correctly predict bifurcations for dilute alloys during solidification. The model predicts a critical diffuseness of the interface at which a plane-front or any other form of diffuse interface will become unstable. A further confidence test for the model is offered in this article by comparing the predicted liquid diffusion coefficients to those obtained experimentally. A comparison of the experimentally determined solute diffusion constant in dilute binary Pb–Sn alloys with those predicted by the various solidification instability models (1953–2011) is additionally discussed. A good predictability is noted for the MEPR model when the interface diffuseness is small. In comparison, the more traditional interface break-down models have low predictiveness.

Dielectric relaxation and local domain structures of ferroelectric PIMNT and PMNT single crystals

AbstractDielectric relaxation properties of ternary Pb(In1/2Nb1/2)O3‐0.49Pb(Mg1/3Nb2/3)O3‐0.27PbTiO3 (PIMNT27) and binary Pb(Mg1/3Nb2/3)O3‐0.27PbTiO3 (PMNT27) single crystals have been investigated. The dielectric constant peak temperature Tm with frequency obeys the Vogel‐Fulcher (V‐F) law. The dielectric constants at temperatures above Tm can be described by the Lorenz‐type relationship. The fitting parameter δA and ΔTm of PIMNT27 are higher than those of PMNT27, indicating stronger relaxation in ternary PIMNT system. Local nanodomain structures were measured by the piezoelectric force microscopy (PFM). The average autocorrelation function technique was applied to quantify these nanoscale domain patterns. The PIMNT27 exhibits smaller size nanodomains and shorter mean local short‐range correlation length compared to PMNT27. The enhanced local disorder in PIMNT is related to the introduction of In3+ in PMNT system, which can enhance the disorder of B‐site ions. In addition, the evolution of local polarization rotation under a step‐increased tip dc voltage and the mean local short‐range correlation length <ξ> as a function of dc voltage were obtained for both PIMNT27 and PMNT27 single crystals, which are crucial parameters for the understanding of the relationship between dielectric relaxation and local domain structures in relaxor‐PbTiO3 systems.

Mutual effects behind the simultaneous removal of toxic metals and cationic dyes by interlayer-expanded MoS2 nanosheets.

Simultaneous removal of coexisting metals and dyes from industrial wastewaters is challenging, and the mutual effects behind the co-adsorption of these pollutants remain unclear. Herein, interlayer-expanded MoS2 (IE-MoS2) nanosheets prepared by a one-pot simple and scalable method were tested to simultaneously remove toxic metals and cationic dyes. The adsorption capacities of IE-MoS2 nanosheets were 499, 423, 500, 355, and 276mg/g for Pb(II), Cu(II), methylene blue, malachite green, and rhodamine B, respectively, in a mono-contaminant system. Interestingly, the sequestration amount of Pb(II) was dependent on the concentrations of dyes in the binary Pb(II)-dye systems, while uptake of cationic dyes was almost not influenced by coexisting Pb(II). The simultaneous adsorption mechanism was further confirmed by spectroscopic methods. The IE-MoS2 nanosheets were easily regenerated and reused for six adsorption-desorption cycles without structure destruction, thus avoiding the potential hazards of nanomaterial to the ecosphere. More interestingly, high-efficiency uptake of Pb(II) from intentionally contaminated natural water and model textile effluent was obtained by using a column filled with IE-MoS2 nanosheets. In summary, IE-MoS2 nanosheets with facile and scalable synthesis method, efficient adsorption performance, and excellent reusability showed potential promise for the integrative treatment of complex wastewater bearing both metals and organic pollutants.

Large Piezoelectric Stability and Low Polarization Fatigue in 6Pb(Sc1/2Nb1/2)O3-70Pb(Mg1/3Nb2/3)O3-24PbTiO3 Crystals

The electrical properties and polarization fatigue of [001]-oriented 6Pb(Sc1/2Nb1/2)O3-70Pb(Mg1/3Nb2/3)O3-24PbTiO3 (6PSN-70PMN-24PT) crystals were investigated. Compared with binary Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) crystals, the ternary 6PSN-70PMN-24PT crystal showed a higher rhombohedral → tetragonal transition temperature (TR-T = 120°C) and a larger coercive field (Ec = 4 kV/cm). It was found that the piezoelectric constant (d33 ≈ 1200 pC/N) and electromechanical coupling coefficient (kt ≈ 61%) were weakly dependent on the thermal annealing temperature (Ta), maintaining over 90% of the original value at Ta < 120°C, indicating excellent piezoelectric thermal stability. Electric fatigue measurements showed that the ternary 6PSN-70PMN-24PT crystal exhibited slight fatigue characteristics below 105 bipolar cycles, while the binary PMN-PT crystal exhibited sudden polarization degradation when the cycle numbers were above 102 cycles. The improved fatigue stability for 6PSN-70PMN-24PT crystals was attributed to the large coercive field. The physical mechanisms of the enhanced coercive field and high transition temperature were discussed based on repulsive energy and polar domains.

Kinetic Studies of Zn(II) Removal from Single and Binary Solutions by Synthetic Hydroxyapatite - Based Nanopowders

A kinetic study has been carried out with two hydroxyapatite nanopowders to establish the mechanism involved in heavy metals removal from aqueous synthetic solutions. The samples of nanohydroxyapatite have been previously characterized. The first sample represents a pure hydroxyapatite (HAP) nanopowder named HAP-1, and the second sample (HAP-2) consist of a mixture of hydroxyapatite (HAP; Ca10(PO4)6(OH)2) and b-tricalcium phosphate (b-TCP; Ca3(PO4)2). Batch experiments with single and binary Zn(II) and Pb(II) aqueous solutions have been performed. According to this research study, it was found that the both nanohydroxyapatite samples show good heavy metals adsorption capacity, and selectivity for Pb(II) ions. A more pronounced decreasing of sorption capacity of Zn(II) ions from binary solutions compared to that registered from single heavy metal ion solutions has been observed. From the kinetic point of view, the sorption process can be described for both heavy metals as a pseudo-second-order kinetic process. According to this model, the Zn(II) and Pb(II) sorption can be achieved by chemical reactions between heavy metals and functional groups of adsorbents. The obtained results are indicative of good hydroxyapatite adsorption ability towards Pb(II) and Zn(II) ions.

Astroserver – Research Services in the Stellar Webshop

Abstract A quick look at research and development in astronomy shows that we live in exciting times. Exoplanetary systems, supernovae, and merging binary black holes were far out of reach for observers two decades ago and now such phenomena are recorded routinely. This quick development would not have been possible without the ability for researchers to be connected, to think globally and to be mobile. Classical short-term positions are not always suitable to support these conditions and freelancing may be a viable alternative.We introduce the Astroserver framework, which is a new freelancing platform for scientists, and demonstrate through examples how it contributed to some recent projects related to hot subdwarf stars and binaries. These contributions, which included spectroscopic data mining, computing services and observing services, as well as artwork, allowed a deeper look into the investigated systems. The work on composite spectra binaries provided new details for the hypervelocity wide subdwarf binary PB 3877 and found diverse and rare systems with sub-giant companions in high-resolution spectroscopic surveys. The models for the peculiar abundance pattern of the evolved compact star LP 40-365 showed it to be a bound hypervelocity remnant of a supernova Iax event. Some of these works also included data visualizations to help presenting the new results. Such services may be of interest for many researchers.

Chemical characteristics and Pb isotopic compositions of PM2.5 in Nanchang, China

In mid-September 2013, PM2.5 samples were collected at six sites in Nanchang, Jiangxi Province, China, to quantify nine water-soluble ions (Ca2+, Mg2+, K+, Na+, NH4+, SO42−, Cl−, F−, NO3−), 29 trace elements (Ba, Zn, Pb, Ni, Mo, Cr, Cu, Sr, Sb, Rb, Cd, Bi, Zr, V, Ga, Li, Y, Nb, W, Cs, Tl, Sc, Co, U, Hf, In, Re, Be, and Ta), and to characterize Pb isotopic ratios (207Pb/206Pb, 208Pb/206Pb, and 207Pb/204Pb) for identifying the main source(s) of Pb. The results showed that the average daily PM2.5 concentration (53.16±24.17) μg/m3 was within the secondary level of the Chinese ambient air quality standard. The combined concentrations of SO42−, NH4+, and NO3− to total measured water-soluble ion concentrations in PM2.5 ranged from 79.40% to 95.18%, indicating that anthropogenic sources were significant. Coal combustion and vehicle emissions were both contributors to PM2.5 based on the NO3−/SO42− ratios. Wushu School experienced the lowest concentrations of PM2.5 and most trace elements among the six sampling sites. Enrichment factor results showed that Tl, Cr, In, Cu, Zn, Pb, Bi, Ni, Sb, and Cd in PM2.5 were affected by anthropogenic activities. Cluster analysis suggested that Cd, Sb, Pb, Re, Zn, Bi, Cs, Tl, Ga, and In were possibly related to coal combustion and vehicle exhaust, while Ni, Nb, Cr, and Mo may have originated from metal smelting. Pb isotopic tracing showed that coal dust, cement dust, road dust and construction dust were the major Pb sources in PM2.5 in Nanchang. Combined, these sources contributed an average of 72.51% of the Pb measured, while vehicle exhaust accounted for 27.49% of Pb based on results from a binary Pb isotope mixed model.

Size-dependent thermodynamic description of the binary Pb-Sn system

Recently, a new thermodynamic description of the binary Pb - Sn system was proposed and it seems to be interesting to extend this description on the system, where size of particles plays a key-role. To obtain this goal a set of surface Gibbs energies was calculated and added to Gibbs energies describing bulk phases. The extended thermodynamic description was used for calculation of size-dependent phase diagram of binary Pb-Sn system. Comparison of calculation with limited literature information allows for statement that the proposed model is in good agreement with experiment.