Stage Of Cu Research Articles

Atomic-Scale Dynamics of the Initial Stages of Cu and Cu Alloy Oxidation

Atomic-Scale Dynamics of the Initial Stages of Cu and Cu Alloy Oxidation

Особливості початкового етапу взаємодії компонентів стопу Cu–Fe під час топлення в індукційній тиґельній печі

Особливості початкового етапу взаємодії компонентів стопу Cu–Fe під час топлення в індукційній тиґельній печі

Deformation Relief of Surface and Plastic Deformation Stages of Cu–12 at % Al Single Crystals

Deformation Relief of Surface and Plastic Deformation Stages of Cu–12 at % Al Single Crystals

Empirical model of the development of electrification process in convective clouds

Results of the development of an empirical model of Cu electrification process are presented. A first part of the paper presents the initial stage of Cu organized electrization. It is based on aircraft investigations. The second part presents Cu characteristics during transition to thundercloud. It is based on the results of 100 experiments, where radar and lightning detection system LS8000 were used. The results confirm the crucial role of ice particles in the process of electrification of the convective cloud at all stages of its development.

Formation of the Cretaceous skarn Cu–Au deposits of the southern Gangdese belt, Tibet: Case studies of the Kelu and Sangbujiala deposits

Mesozoic subduction of Neo-Tethyan oceanic crust caused magmatism that formed numerous Jurassic and Cretaceous intrusions within the southern Gangdese belt of Tibet. These intrusions are associated with the formation of giant Jurassic Xiongcun porphyry Cu deposits, but the prospectivity of other Cretaceous intrusions in this area remains unclear. This study presents new molybdenite Re–Os ages for the Kelu and Sangbujiala Cu–Au skarn deposits within the southern Gangdese belt as well as new geochemical, zircon U–Pb geochronological, and Sr–Nd–Hf isotopic data for the intrusions associated with these deposits. These new data indicate that (1) the Kelu deposit formed at ca. 92 Ma, coeval with emplacement of the diorite and biotite granodiorite intrusions (ca. 92–90 Ma) in this area, and (2) the Sangbujiala deposit formed at ca. 95 Ma, contemporaneous with emplacement of the mineralized biotite granodiorite (ca. 95–92 Ma) in this area. These data suggest that the skarn Cu–Au mineralization in this area formed as a result of Cretaceous magmatism in the southern Gangdese belt. The intrusions associated with the Kelu and Sangbujiala deposits have adakitic affinities with low contents of Y and heavy rare-earth elements and high Sr/Y ratios (22.4–123). These intrusions also have more primitive Sr–Nd isotopic compositions (εNd(t) = 3.99–4.81, (87Sr/86Sr)i = 0.7040–0.7044), lower εHf(t) values (8.0–13.18), and higher zircon EuN/Eu* values (mean of 0.50) than those of contemporaneous but barren adakitic intrusions in this region. This suggests that the mineralization-related intrusions were oxidized and formed from magmas that were generated predominantly by partial melting of subducted Neo-Tethyan slab material without any significant crustal contamination or assimilation of sedimentary material. However, these intrusions contain elevated Th, Ni, and Cr contents, and have high Mg# ratios (43.4–56.9), suggesting that they formed from magmas that interacted with metasomatized mantle wedge peridotite material. Combining our new data with the results of previous research suggests that the southern Gangdese belt records two stages of Cu–Au mineralization related to Neo-Tethyan subduction. The first stage generated the large Xiongcun porphyry Cu–Au deposit and was associated with normal subduction during the Jurassic, whereas the second stage was associated with the formation of the Kelu and Sangbujiala skarn deposits during Cretaceous slab rollback.

Probing Dynamic Processes of the Initial Stages of Cu(100) Surface Oxidation by in situ Environmental TEM and Multiscale Simulations

Probing Dynamic Processes of the Initial Stages of Cu(100) Surface Oxidation by in situ Environmental TEM and Multiscale Simulations

Very High Aspect Ratio (AR>10) through Glass Hole (TGH) Filling in Stagnant Condition By Using DC Plating for Advanced Interposer Applications

High aspect ratio (AR) through glass interposer filling has been widely investigated and developed in the recent years. Most efforts put on blind via filling by using the agitation (i.e., air agitation, cathode rotation, paddle agitation, etc.) or periodic pulse reverse (PPR) plating technique to help improvement of filling performance and enhancement of mass transfer of each component in plating electrolyte. However, high aspect ratio through hole filling has been less addressed because the void or seam defects are easily formed in the through hole. In this study, the AR>10 (AR~12) through glass hole filling with defect-free has been successfully demonstrated under stagnant condition, as shown in Figure 1 by using DC mode of fixed current density plating. Based on the operation condition, the equipment design is simple and the lifetime of additives could be long. Furthermore, the thickness difference between Cu overburden (3.51 μm) and dimple (2.88 μm) is around 0.7 μm, implying that the Cu surface is nearly flat, as shown in Figure 2. This achievement is because the additive of leveler could effectively inhibit the Cu deposition on the Cu seed layer surface, but it does not inhibit Cu deposition in the through hole center. Therefore, the butterfly pattern could be formed in the early stage of Cu filling. Besides, the relatively flat Cu surface is beneficial to post Cu removal process, such as expensive CMP process. Figure 1

Investigating the features in differential absorbance spectra of NOM associated with metal ion binding: A comparison of experimental data and TD-DFT calculations for model compounds

In this study, seven model compounds containing typical functional groups (phenolic and carboxylic groups) present in nature organic matter (NOM) were used to ascertain the nature of the characteristic bands in differential absorbance spectra (DAS) of NOM that are induced by metal ion binding. Some similarities were found between the DAS of the examined model compounds, caffeic acid, ferulic acid, sinapic acid, terephthalic acid, isophthalic acid, esculetin and myricetin and those of NOM. The binding of Cu(II) with carboxylic group might produce two peaks, A1 and A2, while the binding of Cu(II) with phenolic group might produce all four Gaussian peaks, from A1 to A4 displayed in the DAS of NOM. The UV–visible spectra predicted using time-dependent density functional theory (TD-DFT)-based methods met well with the experimental DAS of model compounds at different stages of Cu(II) binding. It demonstrates that the features in absorbance spectra are chiefly caused by HOMO (Highest Occupied Molecular Orbital) - LUMO (Lowest Unoccupied Molecular Orbital) transitions in the molecule and that the appearance of peaks in DAS reflects the changes of the molecular orbitals around reactive functional groups in a molecule before and after metal ion binding. The basis of the DAS features of NOM that are induced by metal ion binding could be identified primarily by the frontier molecular orbital theory.

Low Molecular Weight Components from Various Sources Eliminate Oxidative Stress and Restore Physiological Characteristic of Animals at Early Stages of Cu- Induced Liver Fibrosis Development

Background: Low molecular weight components (proteins and peptides with a molecular weight less than 45 kDa), were isolated from bovine colostrum and Sacharomyces cerevisue and Pleurotus osteatus cell components. It has been determined their effects on physiological characteristics (weight change, body temperature, work capacity) and biochemical parameters (cholesterol, triacylglycerols, creatinine and albumin) and lipid hydroperoxides (figure prooxidant activity) activity of glutathione peroxidase (a measure of antioxidant system) on the model of Cu-induced liver fibrosis. It is shown that irrespective of the method and the source of the LMWCC and the its components eliminated the loss of body weight, the body temperature normalized, and partially restored working capacity of animals with Cu-induced fibrosis. Methods: A three-fold serial intraperitoneal administration of copper sulfate to animals at the dose of 33% of the lethal dose with an interval of 48 hours between injections was accompanied with development of liver fibrosis. Doses of Mix-factor and LMWCC were chosen for the removed of influence of experimental animal’s fibrosis. In the investigation were used the methods of definition of content of cholesterol, triacylglycerols, creatinine and albumin. Besides, it has been activity of glutathione peroxidase and content of lipid hydroperoxides. Results: Content of cholesterol, triacylglycerols, creatinine and albumin remained unchanged in animals with Cuinduced liver fibrosis, a lipid hydroperoxides have increased by 90% in blood serum and 83% in liver mitochondria and activity of glutathione peroxidase was reduced. Introduction of LMWCC and mix-factor increases the activity of glutathione peroxidase and normalize lipid hydroperoxides content. It has been identified S-shaped dose dependence of LMWCC on indicators of proantioxidant system. Conclusion: The results showed that LMWCC obtained from various sources (from cow colostrum or from Pleurotus ostreatus fungi, or from yeast) activated antioxidant defense enzymes (glutathione peroxidase), eliminated oxidative stress in animals with Cu-induced liver fibrosis. These biochemical changes in the body of animals with fibrosis were accompanied by normalization of physiological characteristics (body temperature, growth rate of animals).

Structural evolution of a metal–organic framework and derived hybrids composed of metallic cobalt and copper encapsulated in nitrogen-doped porous carbon cubes with high catalytic performance

We present here the structural evolution of a Prussian blue analogue CuII3[CoIII(CN)6]2 (Cu–Co PBA) controlled by sodium citrate as a function of time at room temperature. We identified the different stages of Cu–Co PBA formation and elucidated its transformation kinetics. Moreover, 3D hybrid composites of nitrogen-doped porous carbon cubes, with cobalt and copper nanoparticles embedded within the well-graphitized shells, were rationally fabricated using Cu–Co PBA as the single precursor. The resulting Cu/Co@NPCC catalysts showed superior catalytic activity in the reduction of 4-nitrophenol to 4-aminophenol. Metallic cobalt and copper cores were leached out by FeCl3 and HCl treatment to determine the catalytically active sites. Results showed that the nitrogen-doped porous carbon still exhibited excellent catalytic performance after the metallic cores were removed. Based on the experimental results, we speculate that the unique structure of metal residues encapsulated inside the graphitic carbon layers may have higher catalytic activity than the metal particles themselves.

Direct-Writing of Cu Nano-Patterns with an Electron Beam

We demonstrate direct electron beam writing of a nano-scale Cu pattern on a surface with a thin aqueous layer of CuSO4 solution. Electron beams are highly maneuverable down to nano-scales. Aqueous solutions facilitate a plentiful metal ion supply for practical industrial applications, which may require continued reliable writing of sophisticated patterns. A thin aqueous layer on a surface helps to confine the writing on the surface. For this demonstration, liquid sample holder (K-kit) for transmission electron microscope (TEM) was employed to form a sealed space in a TEM. The aqueous CuSO4 solution inside the sample holder was allowed to partially dry until a uniform thin layer was left on the surface. The electron beam thus reduced Cu ions in the solution to form the desired patterns. Furthermore, the influence of e-beam exposure time and CuSO4(aq) concentration on the Cu reduction was studied in this work. Two growth stages of Cu were shown in the plot of Cu thickness versus e-beam exposure time. The measured Cu reduction rate was found to be proportional to the CuSO4(aq) concentration.

HIGH SULFIDATION EPITHERMAL MINERALIZATION AND ORE MINERAL ASSEMBLAGES OF CIJULANG PROSPECT, WEST JAVA, INDONESIA

Cijulang is a high-sulfidation epithermal system hosted in the calc-alkaline rocks of andesite lava and lapilli tuff. Mineralization in the prospect is characterized by pyrite-enargite-gold and associated acid sulfate alteration. Studies on ore and gangue mineral assemblages and their mutual textural relationships were carried out in order to explore the paragenetic sequence of mineralization. Hypogene mineralization primarily occurs in the silicic core and the advanced argillic zone in the form of massive replacement, fracture-filling veinlets, vug-filling, patches and dissemination. Mineralization is apparently controlled by both lithology and structures. Common ore minerals include pyrite, enargite, luzonite, tennantite, chalcopyrite, covellite, galena, emplectite and Te-bearing minerals. The paragenetic study indicates that the epithermal prospect evolved from an early stage of intense acid leaching resulting in the formation of vuggy silica and advantage argillic mineral assemblage which was followed by the sulfides deposition. Two metal stages were identified during ore deposition: an early Fe-As-S stage and the later Cu-Fe-As-S stage. The former stage is char- acterized high-sulfidation state sulfides such as enargite/ luzonite+covellite whereas a later stage of Cu- Fe-As–S is represented by intermediate sulfidation state sulfides assemblage of tennantite+chalcopyrite. Gold is probably introduced in the early stage within the ore system and more abundant in the late stage. Keywords: Cijulang, high-sulfidation, acid sulfate, mineralization, enargite, paragenetic, metal stages

Application of Sonication and Microwave Irradiation to Boost Continuous Fabrication of the Copper(II) Oxide Sub-Micron Particles

Viability of the continuous-flow synthesis of rhomboidal copper(II) oxide (CuO) micro- and nanonoparticles was demonstrated. It has been shown that ultrasonic mixing of reactants, in the stage of Cu(OH)2 synthesis, followed by microwave irradiation of the resulting suspension, gives very fine particles of CuO at high yield and within minutes. Near optimal parameters for the synthesis of fine particles in the continuous reactor were determined.

Cu spectroscopy from a z-pinch plasma

Recent improvements in diagnostic techniques at the Sandia Laboratories Z accelerator have facilitated the production of very detailed x-ray spectral data in the range of 1–20 keV. The high energy density plasma produced in a z-pinch is inherently in non-local thermodynamic equilibrium (NLTE). We therefore employ a NLTE collisional equilibrium model in a 1D radiation-magnetohydrodynamics code to simulate the dynamics of the pinch and to generate synthetic emission spectra. We will discuss the effects on radiation spectra and the yields of using simplifying assumptions in the atomic model and/or the radiation transport. X-ray emission from moderately high atomic number plasmas such as Fe and Cu wire array implosions often include substantial 2p–1s K-α radiation. In a z-pinch plasma, K-shell vacancies can be produced by e-beams, hot electrons at the tail of a Maxwellian and also by photopumping from energetic photons emitted near the pinch axis. In the Z-1975 Cu wire implosion, K-α lines from various ionization stages of Cu as well as from minor constituents including Ni, Fe and Cr are observed. We have calculated K-α production within a full simulation of a Cu implosion, including contributions from energetic electrons and photons. Photo-pumped K-α emission can be distinguished from that produced by e-beams; K-shell vacancies will be produced near the axis for a beam, and near the outer edge of the plasma for energetic photons. Spectroscopic modeling of these K-α lines as well as K- and L-shell emission from valence electrons can provide quantitative diagnostics of plasma parameters. This methodology can also be used to investigate K-α emission from other laboratory experiments such as EBIT and astrophysical plasmas.

A comparative study on shock compression of nanocrystalline Al and Cu: Shock profiles and microscopic views of plasticity

Shock compressions of nanocrystalline (nc) metals Al and Cu with the same grain size and texture are studied by using molecular dynamics simulations. Results have revealed that the shock front of both Al and Cu can be divided into three stages: elastic, grain-boundary-mediated, and dislocation-mediated plastic deformation. The transition planes among these three stages are proven to be non-planar by two-dimensional shock response analysis, including local stress, shear, temperature, and atom configuration. The difference between shocked Al and Cu is that the rise rate of the elastic stage of Cu is slightly higher than that of Al, and that the shock-front width of Al is wider than Cu at the same loading conditions. For the plastic stage, the dislocation density of shocked Al is lower than Cu, and the contribution of grain-boundary-mediated plasticity to shock front and strain for nc Al is more pronounced than for nc Cu. These results are explained through intrinsic material properties and atomistic analysis of the plastic process. In the case of the shocked Al sample, partial dislocations, perfect dislocations, and twins are observed, but few evidence of perfect dislocations and twins are observed in the shocked Cu.

Application of spectrum–area fractal model to identify of geochemical anomalies based on soil data in Kahang porphyry-type Cu deposit, Iran

The aim of this study is to identify geochemical anomalies using power spectrum–area (S–A) method based on the grade values of Cu, Mo and Au in 2709 soil samples collected from Kahang porphyry-type Cu deposit, Central Iran. S–A log–log plots indicated that there are three stages of Cu, Mo and Au enrichment. The third enrichment was considered as the main stage for the presence of Cu, Mo and Au at the concentrations above 416ppm, 23ppm and 71ppb, respectively. Elemental anomalies are positively associated with monzo–granite–diorite and breccias units which are in the central and western parts of the deposit. The anomalies are located within the potassic, phyllic and argillic alteration types and also there is the positive correlation between the anomalies and nearing faults in the studied area. The results obtained via fractal model were interpreted accordingly to incorporate the information for the mineralized areas including detailed geological map, structural analysis and alterations. The results show that S–A multifractal modeling is applicable for anomalies delineation based on soil data.

Ab initioatomistic thermodynamics study of the early stages of Cu(100) oxidation

Using an ab initio atomistic thermodynamics framework, we identify the stable surface structures during the early stages of Cu(100) oxidation at finite temperature and pressure conditions. We predict the clean surface, the 0.25 monolayer oxygen-covered surface, and the missing-row reconstruction as thermodynamically stable structures in range of 100--1000 K and 10${}^{\ensuremath{-}15}$--10${}^{5}$ atm, consistent with previous experimental and theoretical results. We also investigate the thermodynamic stabilities of possible precursors to Cu${}_{2}$O formation including missing-row reconstruction structures that include extra on- or subsurface oxygen atoms as well as boundary phases formed from two missing-row nanodomains. While these structures are not predicted to be thermodynamically stable for oxygen chemical potentials below the nucleation limit of Cu${}_{2}$O, they are likely to exist due to kinetic hindrance.

Adsorption Kinetics and Isotherms of Cu (II) and Cd (II) onto Oxidized Nano Carbon Black

A new kind of sorbent, Oxidized Nano Carbon Black (OCB), was prepared with the acid potassium permanganate. The adsorption kinetics,isotherms of Cu (II) and Cd (II) onto Nano Carbon Black(CB) and Oxidized Nano Carbon Black(OCB) were investigated. The experimental data were analyzed by Langmuir, Freundlich isotherm, Pseudo first order equation and Pseudo second order equation. The results demonstrated that the Langmuir isotherm provided a better fit to the experimental data of CB and the OBC fitted well into Freundlich adsorption isotherm. The adsorption capacity of Cu2+ and Cd2+onto oxidized Carbon black was significantly enhanced after modification. The maximum amount of CB was 16.129mg/g for Cu2+, 5.747mg/g for Cd2+, the maximum amount of OCB was 83.333mg/g for Cu2+, 10.3097mg/g for Cd2+, respectively. The Freundlich parameters of OCB were KF, Cu = 0.360, nCu = 1.16, KF, Cd = 1.777 and nCd = 3.086. The values of n > 1 indicated a favorable adsorption process. The study of adsorption kinetic showed that the adsorption stage of Cu and Cd onto sorbents could be divided into two stages: fast reaction and slow reaction. The adsorption kinetic model of metal on OCB followed pseudo second order model well (RCu2=0.985, RCd2=0.987) and the data of CB fitted pseudo first order model well (RCu2=0.983, RCd2=0.998).

In situ ultra-high vacuum transmission electron microscopy studies of the transient oxidation stage of Cu and Cu alloy thin films

Because environmental stability is an essential property of most engineered materials, many theories exist to explain oxidation mechanisms. Yet, nearly all classical oxidation theories assume a uniform growing film, where structural changes were not considered because of the previous lack of experimental procedure to visualize this non-uniform growth in conditions that allowed for highly controlled surfaces and impurities. With the advent of vacuum technologies and advances in microcopy techniques, especially in situ, one can now see structural changes under controlled surface conditions. Here, we present a review of our systematic studies on the transient oxidation stages of a model metal system, Cu, and its alloys, Cu–Au and Cu–Ni, by in situ ultra-high vacuum transmission electron microscopy (UHV-TEM). The dependence of the oxidation behavior on the crystal orientation, oxygen pressure, temperature and alloying is attributed to the structures of the oxygen-chemisorbed layer, oxygen surface diffusion, surface energy and the interfacial strain energy. Heteroepitaxial concepts, developed to explain thin film formation on a dissimilar substrate material (e.g., Ge on Si), described well these initial oxidation stages.

Application of concentration–number (C–N) multifractal modeling for geochemical anomaly separation in Haftcheshmeh porphyry system, NW Iran

Geochemical anomaly separation using the concentration–number (C–N) method at the Haftcheshmeh porphyry system in NW Iran is the aim of this study. We used lithogeochemical data sets to explore Cu, Mo, Au and Re mineralization in gabbroic, dioritic and monzonitic units at the Haftcheshmeh Cu–Mo porphyry system. The obtained results were interpreted using a rather extensive set of information available for each mineralized area, consisting of detailed geological mapping, structural interpretation and alteration data. Threshold values of elemental anomalies for the mineralized zone were computed and compared with the statistical methods based on the data obtained from chemical analyses of samples for the lithological units. Several anomalies at local scale were identified for Cu (40 ppm), Mo (12 ppm), Au (79 ppb), and Re (0.02 ppm), and the results suggest the existence of local Cu anomalies whose magnitude generally is above 500 ppm. The log–log plots show the existence of three stages of Cu and Mo enrichment, and two enrichment stages for Au and Re. The third and most important mineralization event is responsible for presence of Cu at grades above 159 ppm. The identified anomalies in Haftcheshmeh porphyry system, and distribution of the rock types, are mainly gabbrodiorite–monzodiorite, granodiorite and monzodiorite–diorite that have special correlation with Cu–Mo and gabbroic and monzonitic rocks, especially the gabbrodiorite–monzodiorite type, which is of considerable importance. The study shows that these elemental anomalous parts have been concentrated dominantly by potassic and phyllic, argillic and propylitic alterations within the gabbroic, monzonitic and dioritic rocks especially in the gabrodioritic type in certain parts of the area. The results, which were compared with fault distribution patterns, revealed a positive correlation between mineralization in anomalous areas and the faults present in the mineralized system.