High Ag Content Research Articles

Ag paste 및 사포를 이용하여 제작한 Schottky diode의 열처리에 따른 전기적 특성 분석

The electrical characteristics of the device manufactured at room temperature were confirmed to have almost the same current value at the forward or reverse voltage, which means that the Ag electrode formed a resistive contact with the P-type semiconductor. This phenomenon is because some of the components in the Ag paste remain on the electrode and affect the Ag and P-type silicon junction. Diodes with Ag electrodes manufactured at a high temperature of 800 degrees also observed higher turn-on voltages in the forward direction than commercially available devices. This is considered to be due to the remaining elements affecting the contact among the components of Ag and Ni paste. In the reverse voltage, the result of the large change in the current value according to the voltage above -7V is due to the tunneling phenomenon. In conclusion, if a paste with a high content of Ag and Ni in the paste is used and the doping of the P-type semiconductor is reduced, a device with more improved electrical characteristics can be realized.

Effect of silver oxide additives on structural, optical dispersion and protection features of lead boro-phosphate glasses

This work presents the structural, optical, refractive index dispersion, and shielding properties of Ag-containing lead-boro-phosphate glasses. The glasses were prepared using the classic melt-quenching method, in which the Ag2O concentration was varied in each synthesis. The precipitation of Ag NPs was proved by the appearance of the (200) crystal plane in the XRD patterns and confirmed by the homogeneous distribution of spherical agglomerates observed in TEM images. FTIR and Raman analyses have revealed a network depolymerization process resulting from the distortion of the PO4 units and the formation of Ag NPs. Therefore, the Ag ions contribute at high concentrations to an increase in the glass density and a reduction in the optical band gap energy. Ellipsometry parameters indicate that the glass becomes more optically dispersive due to the Ag NPs formation, which improves its performance for several potential applications in multi-functional optical devices. The mass attenuation factors are determined in the energy range of 15 keV–15 MeV and are very sensitive to the silver content at low energies. The Half value layer (HVL) decreases with the amount of Ag2O, indicating the improvement in the material's ability to attenuate radiation. The results show that the glass sample with the highest Ag content has the highest shielding effectiveness.

Transport and thermoelectric properties of crystalline Cu2−xAgxSe alloys prepared by facile method

Crystalline alloys of Cu2−Se containing a transition metal, Earth-abundant and eco-friendly element, are studied in this article as promising eco-friendly thermoelectric materials. Thermoelectric and transport properties of Cu2−xAgxSe (x = 0.00, 0.01, 0.03, 0.05, 0.07) bulk alloys were studied in the temperature range 273–473 K. Crystal structure and surface morphology were tested by X-ray diffraction analysis and scanning electron microscope. Electrical conductivity measurements showed metallic conduction behaviour besides a tremendous decrease in its values with increasing Ag content (x). In contrast, Ag-doping increased the Seebeck coefficient to a large extent. Calculations of the electronic thermal conductivity showed that phonon scattering is increased due to the Ag-doping. The incorporation of Ag-atoms resulted in existence of point defects, introduced secondary phases which significantly reduced the thermal conductivity. Such effects resulted in enhanced ZT, specially at higher Ag-content. The largest ZT value was recorded at 0.25, achieved for Cu1.93Ag0.07Se at 473 K, which is about two times of that observed for the pristine Cu2Se sample. The overall findings of the current study clearly demonstrates that the increasing of the Ag content helps to obtain good TE properties of the cubic Cu2−xAgxSe system, specially at higher temperatures.

Laser surface alloying of titanium alloy with silver: Microstructure, hardness and corrosion property

In this study, silver (Ag) was surface-alloyed in TC4 alloy (Ti6Al4V) with a high-power diode laser (HPDL). The Ag content in the alloyed layers were controlled to be 5 to 24 wt%. The microstructure, hardness and corrosion properties of the alloyed layers are affected by the Ag content. The hardness of TC4 alloy, when laser surface-alloyed with 14 wt% Ag increased from 381 HV0.2 to a maximum value of 569 HV0.2, caused by the formation of hard intermetallic phases (Ti2Ag and TiAg) in the α-Ti matrix. However, with the increase of Ag content to 24 wt% the hardness of the alloy was lowered to 456 HV0.2, result of the formation of a soft Ag-rich phase. In addition, observing a decrease in corrosion resistance of the laser surface-alloyed TC4 with a high Ag content, which is attributed to micro-galvanic effect between the α-Ti and Ti2Ag, TiAg and Ag-rich phase.

Thallium isotopes as indicators of ore mineralization at the Zn-rich sediment-hosted massive sulfide TL Deposit, British Columbia, Canada

Few studies have focused on the application of the Tl isotopic system for geochemical exploration. We report ε 205 Tl values of rock samples from the TL Deposit, British Columbia, Canada – a sediment-hosted massive sulfide (SHMS) deposit with characteristics of a Broken Hill-type deposit – and investigate relationships with major and trace element geochemistry. Maps generated using Tl isotope and trace element data indicate that ε 205 Tl values can potentially be used to fingerprint ore mineralization at the TL Deposit. The sources of Tl and other metals (Ag, Pb, Zn) are assessed using Tl isotope data. Measured ε 205 Tl values exhibit positive correlations with Pb, sedimentary exhalative metal index (Zn + 100*Pb + 100*Tl), and the redox proxy, U/Th, and negative correlations with Be, Cd, Ce, La, Ni and Th. Individual lithologies have distinct Tl isotopic compositions. Metal-rich heavily altered samples have relatively high ε 205 Tl values (−5.0 to −2.5 ε -units) reflecting the euxinic conditions of the global Paleoproterozoic ocean and hydrothermal influence. Samples with lower ε 205 Tl values (−15 to −7.6 ε -units) reflect a combination of their mineralogy (phyllosilicate minerals such as biotite and clinochlore), Tl from sediments reflecting the Tl isotopic composition of modern seawater, and possible low-temperature alteration processes. Samples with high Pb and Ag contents have high ε 205 Tl values, indicating a hydrothermal origin of these metals, whereas Zn is highest in samples with low ε 205 Tl values, indicating a low-temperature or sedimentary origin. Thallium isotopes, paired with conventional geochemical data, show promise as a useful tool for exploration of SHMS deposits with Broken Hill-type characteristics. Supplementary material: Major, minor and trace element contents of samples and reference materials, blank values, correlation coefficient values, and XRD patterns are available at https://doi.org/10.6084/m9.figshare.c.6370671 Thematic collection: This article is part of the Geochemical processes related to mined, milled, or natural metal deposits collection available at: https://www.lyellcollection.org/topic/collections/geochemical-processes-related-to-mined-milled-or-natural-metal-deposits

Shear Fatigue Analysis of SAC-Bi Solder Joint Exposed to Varying Stress Cycling Conditions

Sn–Ag–Cu (SAC) solder alloys are frequently used in electronic assemblies, and their fatigue resistance under various stress cycles is a significant factor that influences the reliability of electronics. Three distinct SAC-based solder joints (SAC305, SAC-Q, and SAC-R) were examined under various stress amplitude cycling and ambient temperature conditions. The stress on individual solder joints alternates between mild stress (MS) and harsh stress (HS) until complete failure. The hysteresis loop was investigated and compared under various stress amplitude cycles. In addition, the morphology and microstructure of the solder joints were analyzed. The results revealed that SAC-Q, with high Bi and Ag content, demonstrated superior fatigue resistance compared with SAC305 and SAC-R under varying stress amplitude conditions. The inelastic work increased with each change between the MS and HS cycles. SAC-Q exhibited solid solution and precipitate hardening mechanisms through the presence of bismuth (Bi) and silver (Ag) in the tin (Sn) lattice. At the same time, SAC305 showed Ag3Sn precipitates hardening, whereas SAC-R, with no Ag, demonstrated solid solution hardening exclusively. Different failure mechanisms were observed depending on the alloy composition and strain rate. SAC305 and SAC-R exhibited ductile failure. However, SAC-Q experienced an interfacial fracture. Excessive Bi may lead to the embrittlement of solder joints and a change in the failure mechanisms during mechanical testing.

Trace Element Composition of Molybdenite: Deposit Type Discrimination and Limitations

Molybdenite is a common sulfide hosting many trace elements. Trace elements in molybdenite from individual deposits have been widely used to constrain the source and conditions of ore-forming fluids. However, the relationship between the trace element composition of molybdenite and deposit types has not been well investigated from a large dataset. Here, simple statistics and partial least squares–discriminant analysis (PLS-DA) were used to determine whether different types of deposits can be distinguished by trace elements in molybdenite and what factors control the variations in trace element composition based on published laser ablation ICP–MS data. Molybdenite from porphyry deposits is separated from that from quartz veins, greisen Sn–W, granite vein Mo, and granodiorite Mo deposits. The former is characterized by relatively high Re, Cu, Ag, Se, Pb, Bi, and Te contents, whereas the latter has higher Ni, Co, Sn, Sb and W contents. Molybdenite from the quartz vein Au ± W deposits (Au-dominated), and porphyry Cu–Au–Mo (moderate Au) are separated from other deposits without gold due to positive correlations with Au, Sb, Te, Pb, and Bi for the former. Assemblages of Au–Sb–Te–Pb–Bi in molybdenite are thus useful to discriminate as to whether deposits contain gold and the degree of gold mineralization. Higher oxygen fugacity is responsible for the relative enrichment of W in molybdenite from greisen Sn–W deposits, whereas lower oxygen fugacity results in the relative enrichment of Re in molybdenite from porphyry Cu ± Mo ± Au and Mo ± Cu ± Au deposits. There are some limitations to using molybdenite as an indicator mineral because of the complex occurrences of elements in molybdenite, large compositional variations within a specific deposit type, and an imbalanced dataset. To develop molybdenite as an indicator mineral tool, further work should be carried out to overcome these limitations. This study provides an attempt to classify deposit types using molybdenite trace elements and has important implications for ore genesis research and mineral exploration.

SOME IMPORTANT CHARACTERISTICS OF POLYMETALLIC LEAD-ZINC ORE IN HAJVALIA MINE, KOSOVO

In this paper are presented general geological data for the polymetallic Hajvalia deposit. In particular, we have presented the scientific results regarding the chemical and mineralogical composition of sulfur mineralizations from the Hajvalia deposit. The distribution of the main metals used during the mining activity in this deposit has been studied with special emphasis. From the microscopic description of the mineral samples in the Hajvalia deposit, the following mineral compositions result: sphalerite, galena, pyrite, chalcopyrite, marcasite, arsenopyrite, pyrrhotite, tenanntite, as well as non-metallic minerals. The geochemical associations indicate the strong connection of Pb with Zn and Ag, and less with Cd and Cu. There is another association of Sb with Cd in antagonism with Cu, and an association of Bi with Cu in antagonism with As. Electron probe analysis shows that galena is quite pure with sporadic high content of Ag (up to 100 ppm). The Fe content in the sphalerite is quite homogeneous and varies from 9 to 11.5%, or 0.18 Fe atoms in the crystallochemical formula. As is known, the Fe content in sphalerite depends on the temperature of the mineral formation and, in some cases, can be used as a geothermometer. The main characteristic of galenites is their "purity", with a very high content of Pb. Ag stands out among the other elements, as does the presence of Hg, more Sb than Bi. The characteristic is the presence of Te and Se in isomorphism with S, always with a predominance of Te. In contrast to galena, the contents of Ag as well as Se and Te are lower while it is found more often in Bi than Sb.

Controlling Threshold and Resistive Switch Functionalities in Ag‐Incorporated Organometallic Halide Perovskites for Memristive Crossbar Array

AbstractHalide perovskites (HPs) can be the effective functional materials for the sneak‐path current issue in the memristive crossbar array. Herein, an efficient strategy is proposed to integrate the HPs‐based bidirectional threshold and bipolar resistive switches (TS and RS). The resistance change characteristics from volatile threshold to nonvolatile resistive switching are modulated by controlling Ag doping concentration in the MAPbI3. HPs provide the diffusive condition and the quantity of Ag regulates the radius of its network. A low amount of Ag contributes to weak network with a short lifetime. However, when the amount of Ag increases, the conductive filament becomes more robust, showing a long lifetime. A MAPbI3:Ag TS with a low Ag content is developed, showing a steep switching slope (1 mV per decade), fast switching speed (< 80 ns), and low off‐current (10 nA). And, a MAPbI3:Ag RS with a high Ag content is developed, showing multilevel storage capability and long retention time (1400 s). Finally, these TS and RS coupled into the 1S‐1R integrated component, resulting the development of the maximum crossbar array size to 1.4 × 1012. This study offers an efficient methodology for tailoring the resistance change characteristics and a promising strategy for practical HPs‐based memristive crossbar application.

Epitaxial Growth of AgxCu1−xI on Al2O3(0001)

Herein, the epitaxial growth of alloy layers and isolated small crystals on using close distance sublimation (CDS) technique is presented. Single‐phase thin films are fabricated up to an Ag content of , while at higher Ag contents the β‐phase is also observed. The epitaxial relationships between the deposited layers and the substrate as well as the structure type are discussed for different alloy compositions. In addition, a further approach is presented for deposition of polycrystalline single‐phase thin films for Ag contents up to based on the solid‐state reaction of AgI layers on substrate with CuI. Furthermore, for differently prepared samples it is shown that the near‐band‐edge emission at 2 K is dominated by excitonic recombination, whereas the spectral position of the emission profile can be tuned by the alloy composition.

Shape-stable Bi-Sn-In alloy/Ag/copper foam composite phase change material for thermal storage and management

With the increasing challenge of heat dissipation in electronic device, the development of rapid thermal storage and management materials with high thermal conductivity becomes an important topic. This study developed a novel low melting point metal composite phase change material composed of Bi-Sn-In alloy, Ag particles (1–4 wt%) and copper foam (apertures 0.25–0.64 mm) using high thermal conductivity synergetic enhanced effect. The Ag particles were uniformly distributed in Bi-Sn-In alloy and they changed to Ag strips with high Ag content, and Bi-Sn-In alloy/Ag can be evenly filled in apertures of copper foam. Bi-Sn-In alloy/Ag/copper foam composite with optimal aperture of 0.42 mm exhibited highest shape stability, because it avoided molten alloy leakage for larger apertures and residual alloy which was not pressed into copper foam for small apertures. As Ag content increases, the melting points of Bi-Sn-In alloy/Ag and Bi-Sn-In alloy/Ag/copper foam with Ag content of 4 wt% respectively increased by 4.91 % and 2.46 %, while their enthalpy slightly decreases by 10.9 % and 2.49 %. More importantly, the synergistic effect of Ag strips and copper skeleton addition formed continuous channels for heat transfer. The thermal conductivities of alloy/Ag (4 wt%) and alloy/Ag (4 wt%)/copper foam were respectively 22.4 and 42.7 Wm−1 °C−1, and they were remarkably higher than that of Bi-Sn-In alloy (16.4 Wm−1 °C−1). Furthermore, thermal management test showed that Bi-Sn-In alloy/Ag/foam copper had the most prominent endothermic and exothermic properties. The outstanding performance of present Bi-Sn-In alloy/Ag/copper foam demonstrates a promising prospect for solving the thermal management problems of contemporary electronic devices.

Ag decorated porous Si structure as potential high-capacity anode material for Li-ion cells

• Sample HCSi was synthesized by MRR of silica powder and improved with Ag nPs. • Silver nanoparticles were deposited in different amounts to increase conductivity. • The kinetics of Li alloying was analysed by chronoamperometric responses CV and EIS. • Sample HCSi10highest intercalation intensity Cs of 3333 mAh/g. • This strategy offers a promising route to advances in anode material for Li-ion cells. Ag decorated honeycomb silicon structure (HCSi) was prepared by magnesiothermic reduction of the synthesized SiO 2 and investigated as a potential anode material for Li-ion batteries. In order to increase the conductivity of HCSi, Ag nanoparticles were deposited on HCSi in different amounts. The characterization of HCSi powder showed the mean particle size of ≈30–40 nm and BET surface area of 102.22 m 2 /g. Sample HCSi10, which had the highest Ag content, showed the highest conductivity of 1.379 × 10 3 S/cm and lower BET surface (34.04 m 2 /g) which is suitable for anode material. These three materials were investigated as anode material in Li-ion cells and their electrochemical properties were investigated by chronoamperometry, cyclic voltammetry and electrochemical impedance spectroscopy. The enhanced electrochemical performance of sample HCSi10 is attributed to the lowest impedance, highest intercalation intensity and current which results in specific capacity of 3333 mAh/g at 0.067 A/g, and 2400 mAh/g at 0.2 A/g.

The effect of surface modification with Ag nanoparticles on 21 nm TiO2: anatase/rutile material for application in photocatalysis

The purpose of this article is to present a perspective, environmentally friendly, and cost-effective chemical approach for preparing photocatalysts that can be used in wastewater treatment. One nanometer-sized Ag nanoparticles (NPs) were deposited on the surface of a commercial titanium dioxide mixture of anatase and rutile. A novel low-temperature chemical method using an ultrasonication process without a reducing agent was applied to surface-modified TiO2 grains with Ag NPs. The materials were characterized by several complementary techniques, such as X-ray powder diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), UV–Vis diffuse reflectance (DRS), Raman spectroscopy, X-ray electron spectroscopy (XPS), Mott-Schottky analysis, and N2 adsorption-desorption measurements. The silver content in the prepared samples ranged from 0.1 to 0.5 wt% (low Ag content) and from 1 to 5 wt% (high Ag content). The photocatalytic performance of the pristine and Ag NPs modified TiO2 powders in photodegradation of the acid orange 7 model dye was studied under ultraviolet (UV), visible (Vis) and UV + Vis radiation. This study explores, for the first time, a photodegradation mechanism for all combinations of wavelengths and silver contents, which is of practical importance in selecting the best photocatalyst and irradiation conditions.

Bonding Performance of Ag-Cu Brazing Solders and Half-Heusler Alloys for High-Performance Thermoelectric Generators.

Due to the uncertainty of the brazing solder composition and its unknown effect on the long-term stability of the interface, the brazing interface connection process for half-Heusler (hH) thermoelectric (TE) devices is still partially concealed and incomplete. In this work, we selected different types of Ag-Cu-based brazing solders with different Ag and Cu contents to assemble hH TE devices, observed the microstructure of the interface contact, and analyzed its formation mechanism. It is found that when the Cu element in the brazing solder is high, it tends to form an intermetallic compound (IMC) layer at the interface, which threatens the life of the device. On the contrary, when the content of the Ag element is high, the formation of the IMC layer will be avoided. Then, the long-term stability of the interface brazed by Ag72Cu28 with high Ag content was verified: the interface connection showed good contact resistivity stability and mechanical reliability; the fabricated uni-couple TE module achieved a maximum output power of 0.28 W and a maximum conversion efficiency of 7.34% at a temperature difference of 538 K. This work summarizes the selection principle of Cu-Ag-based brazing solder when assembling hH TE modules and verifies the long-term stability of the brazed connection interface. The experiment results can provide a reference for the actual fabrication of hH TE devices.

Steam disinfection enhances bioaccessibility of metallic nanoparticles in nano-enabled silicone-rubber baby bottle teats, pacifiers, and teethers

Nano-enabled silicone-rubber articles for feeding or chewing could be a source of metallic nanoparticles (NPs) directly exposed to infants and young children. However, the impact of steam disinfection on release of NPs and the related potential risks to children's health are unknown. Here, we investigated contents and form of Ag and Zn in 57 nano-enabled silicone-rubber baby bottle teats, pacifiers, and teethers of seven countries and examined the impacts of steam disinfection on in vitro bioaccessibility (IVBA) of Ag and Zn in the articles. Nearly 89% articles had a mixture of Ag- and Zn-containing NPs and the teethers had relatively high Ag and Zn contents (up to 501 and 254 µg/g, respectively). Steam disinfection caused rubber decomposition into micro(nano)plastics (0.54−15.7 µm) and NP release from the interior of bulk rubber and micro-sized plastics, thus enhancing the IVBA of Ag and Zn by up to 5.5 times. The findings provide insights into mechanisms for NP release by steam disinfection. Though oral exposure risk assessment suggested low health concerns on individual metal release, our study points out the need to assess the potential health risks of child co-exposure to metallic NPs and micro(nano)plastics.

Effect of Bi, Sb, and Ti on Microstructure and Mechanical Properties of SAC105 Alloys.

The Sn-Ag-Cu (SAC) solder alloys with a low Ag (Ag < 3 wt.%) content have attracted great attention owing to their low cost, increased ability in bulk compliance, and plastic energy dissipation. However, some of their mechanical properties are generally lower than the SAC alloys with a higher Ag content. Adding alloying elements is an effective approach for improving the mechanical properties of the SAC alloys. In this study, the effect of Bi, Sb, and Ti on Sn-1 wt.%Ag-0.5 wt.%Cu (SAC105) solder alloys was investigated. The SAC solders with four compositions: SAC105-1 wt.%Bi, SAC105-1 wt.%Sb, SAC105-1 wt.%Bi-1 wt.%Sb, SAC105-1 wt.%Bi-1 wt.%Sb-0.4 wt.%Ti were prepared. The microstructure and phase compositions were characterized using electron scanning microscopy, and X-ray diffraction. The thermal properties and wettability were also examined. Uniaxial tensile tests and nano-indentation tests were conducted to evaluate the mechanical properties. The results show that adding Bi or Sb could increase the strength of SAC105 alloys mainly due to the solid solution strengthening effect. The creep resistance of SAC105 alloys was also improved with the additions of Bi and Sb. The co-additions of Bi and Sb into SAC105 alloys exhibit an enhanced creep resistance than that calculated by the theoretical calculation. The further addition of Ti into SAC105-1Bi-1Sb alloys demonstrated a much-improved creep resistance, which could be attributed to the synergistic effects of both solid solution strengthening and the precipitation hardening effects.

Design and preparation of a biomedical titanium alloy with low elastic modulus and high antibacterial property based on Ti-Mo-Ag system

Titanium and titanium alloys have been widely used as biomedical materials as a result of low density, high specific strength, good biological propertise, good mechanical compatibility and easy processing. However, problems such as stress shielding and bacterial infection often occur in the clinical application. In this paper, Ti-15Mo-xAg (x = 10, 12) alloys were designed and prepared to obtain low elastic modulus and excellent antibacterial ability. We studied the microstructure, mechanical properties, antibacterial properties and cytocompatibility by scanning electron microscopy, differential scanning calorimeter, X-ray diffraction, micro-hardness instrument and plate counting method. The calculated results indicated that Ti-15Mo alloys with different Ag contents could be β-type or near β-type alloy with potential of a low elastic modulus. Microstructure results demonstrated that the increasing Ag content from 10 wt% to 12 wt% increased the phase transformation temperature and resisted the formation of ω phase in Ti-Mo-Ag system. Both the elastic modulus and the antibacterial ability were significantly influenced by the ageing treatment and Ag content due to the phase constitution, and high Ag content and the precipitation of Ti 2 Ag were beneficial to the antibacterial performance but increased the elastic modulus. Cell assessment showed that Ti-Mo-Ag alloys did not have cytotoxicity to MC3T3. Ti-15Mo-10Ag alloy exhibited strong antibacterial rate of 99.5%, good cellular compatibility and low elastic modulus of 85 GPa, which suggests that this alloy might be a highly competitive medical material. • The effects of Ag content and heat treatment process on elastic modulus and antibacterial properties were studied. • Ti-15Mo-10Ag and Ti-15Mo-12Ag alloy had no cytotoxicity to MC3T3 cell. • Ti-15Mo-10Ag exhibited low elastic modulus and good antibacterial ability after the ageing treatment of 650 ℃.

Geochemistry, sulfur and lead isotopic composition of hydrothermal sulfide from the Duanqiao hydrothermal field on the Southwest Indian Ridge: implications for ore genesis

ABSTRACT Hydrothermal activities on ultraslow-spreading ridges exhibit diverse characteristics, long histories with multiple participants, and might form large-scale, high-grade sulfide deposits. The Duanqiao hydrothermal field (DHF) is located at the segment with the thickest oceanic crust and a large axial magma chamber on the Southwest Indian Ridge, providing unique perspective of sulfide metallogenesis on ultraslow-spreading ridges. Previous studies revealed that DHF sulfide exhibits distinct features of enrichment of ore-forming elements in comparison with those of hydrothermal fields on sediment-starved mid-ocean ridges. However, the genesis and processes responsible for such differences remain poorly constrained. In this study, mineralogical, geochemical and S and Pb isotopic analyses were performed on relict sulfide mound samples to characterize DHF formation. The samples show clear concentric mineral zonation from the interior to the exterior wall. Assemblages of chalcopyrite, sphalerite, and pyrite are distributed mainly in the interior wall, whereas pyrite and marcasite are distributed mainly in the exterior wall. The low Cu content and Pb isotopic composition of the sulfide indicate that the metals are derived mainly from basement basalts. The δ34S values exhibit positive values distributed over a reasonably narrow range (2.42‰–7.97‰), which suggests approximately 62.1%–88.5% of S with basaltic origin. Compared with most hydrothermal fields along the sediment starved mid-ocean ridges, the DHF sulfide shows particularly high contents of Pb (263–2630 ppm), As (234–726 ppm), Sb (7.32–44.3 ppm), and Ag (35.2 to >100 ppm). The δ34S values exhibit an increasing tendency from the sample exterior to the interior. We propose that these features probably reflect the existence of a subsurface zone refining process. Our results provide new insight into the sulfide formation process and contribute to understanding the metallogenic mechanism of hydrothermal sulfides on ultraslow-spreading ridges.

Electron-Induced Decomposition of Different Silver(I) Complexes: Implications for the Design of Precursors for Focused Electron Beam Induced Deposition.

Focused electron beam induced deposition (FEBID) is a versatile tool to produce nanostructures through electron-induced decomposition of metal-containing precursor molecules. However, the metal content of the resulting materials is often low. Using different Ag(I) complexes, this study shows that the precursor performance depends critically on the molecular structure. This includes Ag(I) 2,2-dimethylbutanoate, which yields high Ag contents in FEBID, as well as similar aliphatic Ag(I) carboxylates, aromatic Ag(I) benzoate, and the acetylide Ag(I) 3,3-dimethylbutynyl. The compounds were sublimated on inert surfaces and their electron-induced decomposition was monitored by electron-stimulated desorption (ESD) experiments in ultrahigh vacuum and by reflection−absorption infrared spectroscopy (RAIRS). The results reveal that Ag(I) carboxylates with aliphatic side chains are particularly favourable for FEBID. Following electron impact ionization, they fragment by loss of volatile CO2. The remaining alkyl radical converts to a stable and equally volatile alkene. The lower decomposition efficiency of Ag(I) benzoate and Ag(I) 3,3-dimethylbutynyl is explained by calculated average local ionization energies (ALIE) which reveal that ionization from the unsaturated carbon units competes with ionization from the coordinate bond to Ag. This can stabilise the ionized complex with respect to fragmentation. This insight provides guidance with respect to the design of novel FEBID precursors.

Detrimental and essential elements in fruiting bodies of wild-growing fungi Coprinus comatus, Flammulina velutipes, and Armillaria ostoyae

Edible medicinal wild-growing fungi Coprinus comatus, Flammulina velutipes, and Armillaria ostoyae were analyzed with regard to the contents of 21 elements in their fruiting bodies. The samples were collected from selected sites in South Bohemia, the Czech Republic. C. comatus concentrated Ag, Cd, Cu, Se, and Rb with bioconcentration factors of 12, 2.5, 2.3, 1.8, and 1.1, respectively. High contents (all values expressed in mg kg−1 dry matter) of Al (260), Ca (480), Cu (61), Fe (340), Mg (1400), and Zn (86) were determined for this species. F. velutipes was characterized with markedly high contents of Ca (360), Fe (110), Mg (1200), Mn (26), and Zn (98), respectively. A considerably high content of Ag (5.6) was revealed for A. ostoyae. High contents of Ca (150), Cu (28), Fe (190), Mg (1100), Mn (30), and Zn (40) were determined in fruiting bodies of this species as well. The data concerning the detrimental elements in fruiting bodies of studied fungi indicate no considerably negative effect on human health if they are consumed as a delicacy or used in alternative medicine.