Observation Of Cu Research Articles

Direct observation of Cu in high-silica chabazite zeolite by electron ptychography using Wigner distribution deconvolution

Direct observation of Cu in Cu-chabazite (CHA) zeolite has been achieved by electron ptychography using the Wigner distribution deconvolution. The imaging properties of ptychographically reconstructed images were evaluated by comparing the intensities of six-membered-ring columns of the zeolite with and without Cu using simulated ptychography images. It was concluded that although false contrast may appear at Cu-free columns for some acquisition conditions, ptychography can discriminate columns with and without Cu. Experimental observation of CHA with and without Cu was performed. Images obtained from the Cu-containing sample showed contrast at the six-membered-rings, while no contrast was observed for the Cu-free sample. The results show that ptychography is a promising technique for visualizing the atomic structures of beam-sensitive materials.

Effects of Ag on phase transformation of Cu3Sb at high temperatures

Effects of Ag on the phase transformation of Cu3Sb were investigated through scanning electron microscopy, energy-dispersive X-ray spectroscopy, and high-temperature X-ray diffraction (XRD) measurements. Observations of Cu–Sb–Ag alloys following heat treatment at 500 °C revealed that Ag dissolved up to 11 at.% in a cubic β-Cu3Sb phase stable only at high temperatures. XRD measurements confirmed that while a transformation from the β-Cu3Sb phase to orthorhombic ε-Cu3Sb phase occurred at 440 °C in the binary system, the transformation occurred below 380 °C in the alloy containing 5% Ag, suggesting the enhanced stability of the β-Cu3Sb phase owing to Ag. Furthermore, during measurements above 420 °C on alloys with a composition consistent with that of Cu3−xAgxSb containing 8–14% Ag (i.e., x = 0.32–0.56), the formation of a new alloy phase with a hexagonal structure (a = 4.3416 Å and c = 7.6864 Å at 500 °C) was observed. The crystal structure of the new alloy phase was inferred to be of the Na3As type, which belongs to the space group P63/mmc. Based on observations of alloys with various compositions, an isothermal section of the Cu–Sb–Ag ternary phase diagram at 500 °C was constructed.

Structure and heat resistance of high strength Al–3.3%Cu–2.5%Mn–0.5%Zr (wt%) conductive wire alloy manufactured by electromagnetic casting

The Al-3.3Cu-2.5Mn-0.5Zr (wt%) alloy was manufactured by electromagnetic casting and further subjected to processing including cold rolling, drawing and annealing. Excellent processability of the alloy at cold rolling and drawing was observed due to the ultrafine as-cast structure. Annealing of the cold-rolled strip at 350 °C for 48 h insignificantly reduces the hardness, but the electrical resistivity (ER) decreases by almost 3 times (from 115 to 40 nΩm). The large deformation during rolling (reduction 98.4%) and high fraction of the Zr- and Mn-bearing nano dispersoids (Al20Cu2Mn3 and Al3Zr-L12) stipulated the high set of mechanical properties and electrical conductivity after annealing at 400 °C (UTS~330 MPa, YS~250 MPa, EL~7%, 42.5 IACS). A model of ER dependence on the phase composition was proposed. While at above 400 °C there is a good agreement between the calculated and experimental values, the scatter at lower temperatures is attributed to exposure times insufficient for achieving the equilibrium (Al) composition. Atom probe tomography was employed for observation of Cu, Mn and Zr concentrations in (Al) after annealing at 350–450 °C. According to the experimental results and root-mean-square calculations, annealing at between 350 and 400 °C allows achieving (Al) compositions close to the equilibrium in reasonable time while with decreasing temperature the diffusion of Zr in (Al) decreases and thus it requires extremely long exposures, e.g. at 300 °C it is about 23,000 h. From this viewpoint annealing at below 350 °C is unreasonable for achieving lower ER.

Intramolecular electron transfer in Cu(ii) complexes with aryl-imidazo-1,10-phenanthroline derivatives: experimental and quantum chemical calculation studies

First observation of Cu(ii)–Cu(i) autoreduction in complex with aryl-imidazo-1,10-phenanthroline derivatives.

Exploring tarnished daguerreotypes with synchrotron light: XRF and \u03bc-XANES analysis

We report on the elemental and chemical characterization of tarnish on a historic daguerreotype plate. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy reveal the presence of C, O, Na, K, P, Cl, Hg, Ag, Cu, S and Au. Synchrotron based X-ray absorption near edge structure (XANES) spectroscopy, together with two-dimensional X-ray fluorescence (XRF) microscopy, provide information beyond the elemental distribution and speciation of the daguerreian tarnish features, revealing the presence of NaCl, KCl, HgCl2, HgSO4, CuS, and Ag2S on the surface. Through the application of synchrotron XRF, the distributions of Ag and S were found to be inversely correlated. This suggests a preferential accumulation of S within high-density particle regions. Spectroscopic investigation at different regions within the XRF image showed that blemish regions contained degradation products such as NaCl and KCl with AgCl noted in the surrounding regions. The observation of Cu on the surface, in the form of CuS, may either be a result of Cu diffusing through grain boundaries and/or holes in the Ag, or from the accretion of Cu salts, such as basic sodium copper carbonate, from the deterioration of the above cover glass. Silver halides (AgCl, AgBr and AgI) were also detected with XANES. This may be the result of either environmental conditions or from residual products from the production process of the plate. These results point to the interaction between deterioration products from the cover glass with the daguerreotype surface as one, but not the only, source of the tarnish.

TEM Observation of Cu and Ag Added Al-Mg-Si Alloy

TEM Observation of Cu and Ag Added Al-Mg-Si Alloy

Medical applications of Cu, Zn, and S isotope effects.

This review examines recent applications of stable copper, zinc and sulfur isotopes to medical cases and notably cancer. The distribution of the natural stable isotopes of a particular element among coexisting molecular species varies as a function of the bond strength, the ionic charge, and the coordination, and it also changes with kinetics. Ab initio calculations show that compounds in which a metal binds to oxygen- (sulfate, phosphate, lactate) and nitrogen-bearing moieties (histidine) favor heavy isotopes, whereas bonds with sulfur (cysteine, methionine) favor light isotopes. Oxidized cations (e.g., Cu(ii)) and low coordination numbers are expected to favor heavy isotopes relative to their reduced counterparts (Cu(i)) and high coordination numbers. Here we discuss the first observations of Cu, Zn, and S isotopic variations, three elements closely related along multiple biological pathways, with emphasis on serum samples of healthy volunteers and of cancer patients. It was found that heavy isotopes of Zn and to an even greater extent Cu are enriched in erythrocytes relative to serum, while the difference is small for sulfur. Isotopic variations related to age and sex are relatively small. The 65Cu/63Cu ratio in the serum of patients with colon, breast, and liver cancer is conspicuously low relative to healthy subjects. The characteristic time over which Cu isotopes may change with disease progression (a few weeks) is consistent with both the turnover time of the element and albumin half-life. A parallel effect on sulfur isotopes is detected in a few un-medicated patients. Copper in liver tumor tissue is isotopically heavy. In contrast, Zn in breast cancer tumors is isotopically lighter than in healthy breast tissue. 66Zn/64Zn is very similar in the serum of cancer patients and in controls. Possible reasons for Cu isotope variations may be related to the cytosolic storage of Cu lactate (Warburg effect), release of intracellular copper from cysteine clusters (metallothionein), or the hepatocellular and biosynthetic dysfunction of the liver. We suggest that Cu isotope metallomics will help evaluate the homeostasis of this element during patient treatment, notably by chelates and blockers of Cu trafficking, and understand the many biochemical pathways in which this element is essential.

Effects of Heat Treatment and Deformation on 2H and 18R Martensites in Cu–9.97 % Al–4.62 % Mn Alloy

In this study, some physical and mechanical properties of martensitic transformation in Cu–9.97 % Al–4.62 % Mn (wt%) alloy were investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and compression deformation test techniques. In SEM and XRD observations of Cu–9.97 % Al–4.62 % Mn alloy, two kinds of martensitic phases: thermally and deformation effect, \({\beta_{1}^{\prime}}\) and \({\gamma_{1}^{\prime}}\) from DO3 parent phase, and the type of the produced martensite structures were noted.

Assessment of heavy metals and their interrelationships with some physicochemical parameters in eco-efficient rivers of Himalayan region

Most precious and world famed Himalayan rivers like Ganga, Yamuna, and their tributaries are originated from Uttarakhand state of India. Over the years, increased industrial activities and urban growth along the rivers and lakes have resulted in increased load over the water bodies. In the present study, a comparison of characteristics of water quality with respect to heavy metals (Fe, Zn, Cu, and Pb) and their interrelationships with some physiological parameters during different seasons of year 2010 has been made in the water bodies flowing through the two geographical regions, namely Garhwal and Kumaon regions of the Himalayan State of India. All observed values of Pb, 02 observation of the Cu, and 59 observations of Fe are found exceed with the WHO standard for drinking water; 83 observations of Pb, 110 observations of Cu, and 59 observations of Fe are found exceed with the Bureau of Indian Standards. However, none of the observation of Zn is found exceeding with the standard limit. Cu shows the highest concentration 7.30mg/l among all observations and also its higher concentration in Kumaon rivers. All the metals show negative correlation with dissolved oxygen and pH. Fe in river Yamuna system and Zn in Kumaon rivers show significant temporal variations at 90% level of significance (LOS). However, no significant temporal difference of remaining metals is observed even at 95% LOS. All metals except Fe in river Yamuna system show very significant variation in spatial distribution in different river systems at 95% LOS.

TEM Observation of Cu and Ag Addition Al-Mg-Si Alloys

It has been known that Cu-and Ag-addition Al-1.0mass%Mg2Si alloys (Al-Mg-Si-Cu alloy and Al-Mg-Si-Ag alloy) have higher hardness and elongation than those of Al-1.0mass%Mg2Si alloy. In this study, the aging behaviour of Al-Mg-Si-Cu alloy, Al-Mg-Si-Ag alloy and (Cu+Ag)-addition Al-1.0 mass% Mg2Si alloy (Al –Mg –Si-Cu-Ag alloy) has been investigated by hardness test and TEM observation. The Al-Mg-Si-Cu-Ag alloy has the fastest age-hardening rate in the early aging period and the finest microstructure at the peak hardness among three alloys. Therefore the microstructure of the precipitate in Al–Mg–Si-Cu-Ag alloy has been investigated by HRTEM observation to understand the effect of Cu and Ag addition on aging precipitation.

Extreme-ultraviolet spectra of highly charged Pt ions with several valence-shell electrons: Observation and accurate calculations

Previous observations of Cu- through Ge-like high-$Z$ ions have demonstrated that accurate measurements and theory agree well for ions with a single valence electron but that additional electrons in the valence shell cause progressively worsening computational problems. We have obtained highly resolved euv spectra of Pt ($Z=78$) ions in an electron-beam ion trap. The measured wavelengths are compared to the results of a number of recent large-scale calculations, including our own multireference M\o{}ller-Plesset computations. The latter calculations match the best for Cu- and Zn-like ions and represent an order-of-magnitude improvement in predictive accuracy for Ga- and Ge-like ions.

Probing Cyanocuprates by Electrospray Ionization Mass Spectrometry

Solutions of CuCN/(RLi)n (n = 0.5, 0.8, 1.0, and 2.0 and R = Me, Et, nBu, sBu, tBu, and Ph) in tetrahydrofuran are analyzed by electrospray ionization mass spectrometry. In all cases, organocuprate anions are observed, whose exact nature depends on the reagent stoichiometry. While cyanide-free Lin−1CunR2n− anions completely predominate for CuCN/(RLi)2 solutions, cyanide-containing Lin−1CunRn(CN)n− complexes prevail for CuCN/(RLi)n reagents with n ≤ 1. Mixing studies with CuCN/MeLi/RLi as well as gas-phase fragmentation experiments of the mass-selected anions provide further insight into the relative stability and the likely structural composition of polynuclear cuprates. The thus obtained information not only agrees quite well with previous results from spectroscopic and crystallographic work but moreover reveals clear trends of how different organyl substituents influence the aggregation and ion-pairing behavior of cyanocuprates. In addition, the observation of Cu(+2)-containing cyanocuprate complexes fo...

Interface electronic structure and dynamics of tris-(8-hydroxyquinoline) aluminum on Cu(100)

We have investigated the evolution of occupied and unoccupied electronic states of tris-(8-hydroxyquinoline) aluminum (Alq3) molecules adsorbed on Cu(100) using ultraviolet photoelectron spectroscopy and interferometric time-resolved two-photon photoemission (ITR-2PPE). The adsorption of Alq3 lowers the work function of the surface, which allows an unambiguous observation of Cu(100) surface resonance coupled with d-band state and molecular interband transition in our ITR-2PPE setup. No evidence of an anion state, which used to be formed by dynamic charge transfer from metal to a molecular unoccupied state, is identified. Analysis of relaxation dynamics of the transiently occupied electronic states shows that the lifetimes for those excited states at this surface are independent of the Alq3 thickness. These results indicate that the Alq3–Cu(100) interface is described as a weak van der Waals interaction.

Polycrystalline oxides formation during transient oxidation of (001) Cu–Ni binary alloys studied by in situ TEM and XRD

The nucleation and growth of Cu2O and NiO islands due to oxidation of CuxNi1–x(001) films were monitored, at various temperatures, by in situ ultra-high vacuum (UHV) transmission electron microscopy (TEM) and in situ synchrotron X-ray diffraction (XRD). In remarkable contrast to our previous observations of Cu and Cu–Au oxidation, irregular-shaped polycrystalline oxide islands formed with respect to the Cu – Ni alloy film, and an unusual second oxide nucleation stage was noted. In situ XRD experiments revealed that NiO formed first epitaxially, then other orientations appeared, and finally polycrystalline Cu2O developed as the oxidation pressure was increased. The segregation of Ni and Cu towards or away, respectively, from the alloy surface during oxidation could disrupt the surface and cause polycrystalline oxide formation.

Polycrystalline oxides formation during transient oxidation of (001) Cu–Ni binary alloys studied byin situTEM and XRD

The nucleation and growth of Cu2O and NiO islands due to oxidation of CuxNi1–x(001) films were monitored, at various temperatures, by in situ ultra-high vacuum (UHV) transmission electron microscopy (TEM) and in situ synchrotron X-ray diffraction (XRD). In remarkable contrast to our previous observations of Cu and Cu–Au oxidation, irregular-shaped polycrystalline oxide islands formed with respect to the Cu – Ni alloy film, and an unusual second oxide nucleation stage was noted. In situ XRD experiments revealed that NiO formed first epitaxially, then other orientations appeared, and finally polycrystalline Cu2O developed as the oxidation pressure was increased. The segregation of Ni and Cu towards or away, respectively, from the alloy surface during oxidation could disrupt the surface and cause polycrystalline oxide formation.

Observation of Cu2+–H2 Interactions in a Fully Desolvated Sodalite‐Type Metal–Organic Framework

Metal–H2 binding: A new tetrazolate-based metal–organic framework exhibits high H2 uptake at low temperature and moderate pressure. The evacuation of coordinated solvent molecules from Cu2+ ions within the framework provides strong binding sites for H2 molecules (see picture; Cu purple, C gray, N blue, Cl green).

Observation of Cu2+–H2 Interactions in a Fully Desolvated Sodalite‐Type Metal–Organic Framework

Observation of Cu²⁺–H₂ Interactions in a Fully Desolvated Sodalite‐Type Metal–Organic Framework

Oxidation Kinetics of Cu-Ni Alloy Observed by in situ UHV-TEM

AbstractThe nucleation and growth of Cu2O and NiO islands due to oxidation of Cu-24%Ni(001) films were monitored at various temperatures by in situ ultra-high vacuum (UHV) transmission electron microscopy (TEM). In remarkable contrast to our previous observations of Cu and Cu-Au oxidation, irregular-shaped polycrystalline oxide islands were observed to form with respect to the Cu-Ni alloy film, and an unusual second oxide nucleation stage was noted. Similar to Cu oxidation, the cross-sectional area growth rate of the oxide island is linear indicating oxygen surface diffusion is the primary mechanism of oxide growth.

Cu and Zn in different stellar populations: Inferring their astrophysical origin

Copper and Zinc behave differently in unevolved stars of various metallicities and stellar populations. Current hypotheses on the astrophysical origin of both elements are highly debated. It has been advanced in previous works ([Matteucci, F., Raiteri, C., Busso, M., Gallino, R. and Gratton, R. A&A 272 (1993) 421,Mishenina, T.V. et al. A&A 396 (2002) 189]) that most solar Cu and Zn were synthesized in Type la Supernovae, although present theory of SNIe explosions predicts very little contribution to both elements [Thielemann, F.-K., Nomoto, K. and Yokoi, K. A&A 158 (1986) 17]. We have collected a large sample of recent high-resolution spectroscopic observations of unevolved stars in the Galactic halo, thick-disk and thin-disk, in bulge-like stars, globular clusters, Omega Cen, and Dwarf Spheroidal systems. Then we compare spectroscopic observations of Cu and Zn with present stellar nucleosynthesis theory. Cu is the best signature of a secondary-like production in massive stars by neutron captures with a small primary contribution by explosive nucleosynthesis. Zn needs a more complex description. No need of extra contribution by SNIa is required.

Second harmonic observation of Cu [formula omitted] surface: in situ measurements during molecular adsorption

Second harmonic generation (SHG) spectroscopy using a tunable femtosecond laser has been demonstrated as an effective and a practical in situ monitor of surface electronic states during adsorption processes. We have successfully shown this technique to be suitable for the study of surface electronic states, not only those induced by adsorbed molecules but also those associated with clean surfaces. By observing the change in the SH signals from a Cu(1 1 1) surface during exposure to benzene or CO molecules, we discovered new resonances of the clean Cu surface that could not be ascribed to the well-known surface state (SS)–image state (IS) transition. One of these was from a surface site that is less likely to adsorb benzene, where the SH signal intensity was kept constant until the Cu surface was covered by the sub-monolayer.