Copper Chains Research Articles

Frequency domain attention network for copper chain defect detection in tobacco cutting machine

AbstractThe detection of defects on the copper chain in the production process of tobacco cutters is crucial for ensuring product quality. Traditional defect detection methods often rely on spatial domain image analysis, which not only has a large computational load but also performs poorly in handling high‐frequency noise and complex backgrounds. To address this issue, this paper proposes a novel neural network model based on frequency domain analysis, called frequency domain attention network. This network first utilizes discrete cosine transform to transform the image from the spatial domain to the frequency domain, effectively reducing computational complexity and improving processing speed. Subsequently, through the innovative frequency domain attention module, the network automatically identifies and enhances key discriminative features in the frequency domain, thereby strengthening the model's ability to identify defects. Finally, the frequency domain attention map, after feature extraction and integration, is inputted into the coupling detection head to achieve high‐precision defect detection. The experimental results show that our method outperforms the SOTA method with an increase of 0.03 in AP and 21 in FPS.

Biochemical properties of winter wheat (Triticum vulgare L.) under Zn and Cu balance in the soil-culture system

The role of trace elements as a factor in the formation of biochemical features of grain crops is a debatable and extremely understudied issue. At the same time, the ecological importance of the balance of nutritional elements for the normal functioning of plants is widely highlighted in biology and agronomy. The purpose of the study was to determine the interdependence of biochemical and biogeochemical features and to determine the influence of the biogeochemical balance of Zn and Cu on the biochemical parameters of wheat in various agrolandscapes of the forest-steppe of Ukraine. We has been developed an original method of regional spatial correlation between the balance of micronutrients in the soil-crop system and biochemical indicators of the quality of plant products. Spatial correlation was implemented in wheat growing areas in two agrolandscapes, namely, with dark gray podzolized soils in the Kyiv region and gray podzolized soils in the Vinnytsia region. Regional features of the distribution of Zn and Cu in the agricultural landscape are summarized by their biogeochemical formulas, which highlight 5 evaluation characteristics of the soil-culture system in subsoil rocks, soils, and grain crops. Features of the quality of wheat in the territory of agrolandscapes are determined by statistical data on the content of protein, gluten, and vitreousness. The result of the spatial correlation of the specified characteristics is the determination of the interdependencies of the biochemical parameters of the nutritional quality of wheat and the balance of Zn, Cu in the investigated agrolandscapes. The determined differences between the features of the links of the biogeochemical chains of zinc and copper indicate the possibility of a decrease in the vitreousness and protein in wheat grains as a result of the lack of this nutrient microelement, even under the conditions of their natural and agrogenic accumulation in the soil. The inconsistency of the processes in the soil and the agrocenosis of the agrolandscape indicates the expediency of changes in soil protection and agrochemical melioration systems. Special attention needs to be paid to research on foliar nutrition of wheat culture, as a factor in increasing the biophilicity of nutrient microelements and the corresponding increase in the protein content and vitrification of wheat grain.

Nizkorazmernyy magnetizm v namibite Cu(BiO)2VO4OH

A synthetic analog of rare secondary mineral namibite Cu(BiO)2VO4OH has been obtained by the hydrothermal method. The crystal structure of this compound contains isolated uniform chains of vertex-connected copper–oxygen octahedra. Magnetic susceptibility (χ) and magnetization (M) measurements have not indicated the long-range order in the temperature interval 2–300 K. Specific heat (Cp) measurements suggest the formation of a spin-liquid state at low temperatures. X-band electron paramagnetic resonance data recorded at low temperatures have demonstrated only a signal from impurities. First-principles calculations have estimated the exchange interaction in the chains as J = 555 K, whereas exchange interactions between the chains turn out to be one to two orders of magnitude smaller. Thus, namibite represents a rare example of an unordered half-integer spin chain.

Design and application of copper chain removal device for TOBSPIN tobacco cutter

In order to solve the difficulty in disassembling the copper chain of the TOBSPIN tobacco cutter, an automatic disassembly device was developed based on Solidworks mechanical simulation design software. Firstly, construct the overall structural model of the device by Solidworks. Then determining the feasibility of the equipment operation by the force analysis of the system. Lastly, the device can be automatically started and stopped by controlling PLC program. The results show that it takes 41.24 hours for manual disassembly per machine, and 11.18 hours to apply the automatic device, which reduces the working time by 72.9%. The device can provide technical support for improving the disassembly efficiency of the equipment and reducing operating intensity.

Analysis of China's non-ferrous metals industry's path to peak carbon: A whole life cycle industry chain based on copper

Copper is an essential nonferrous metal, and the adjustment of its whole industry chain structure is conducive to realizing a carbon peak in the nonferrous metal industry. We have performed a life cycle assessment to calculate the carbon emissions of the copper industry. Based on the carbon emissions scenarios of shared socioeconomic pathways (SSPs), we have utilized material flow analysis and system dynamics to analyze the structural changes in the copper industry chain from 2022 to 2060 in China. The results show that (1) the flows and in-use stocks of all types of copper resources will increase significantly. The overall copper supply may meet demand around 2040–2045 due to secondary copper production potentially replacing primary copper production to a large extent, and trade supply is the primary pathway for meeting copper demand. (2) The total carbon emissions from the regeneration system are the smallest (4 %), followed by the production and trade subsystems, accounting for 48 %. The embodied carbon emissions from copper product trade in China have expanded annually. (3) Under the SSP scenario, the copper chain carbon emission peak will be achieved by approximately 2040. Based on a balanced copper supply and demand scenario, the recycled copper recovery efficiency must reach 84.6 %, and the energy structure (the proportion of non-fossil energy in electricity) must reach 63.8 % by 2030 to achieve the carbon peak target for the copper industry chain in China. The above conclusions indicate that actively promoting adjustments in the energy structure and resource recovery processes may help encourage the carbon peak of nonferrous metals in China by realizing the carbon peak of the copper industry.

Exchange coupling in a thiocyanato-bridged copper(II) chain: Computational approach to magnetostructural correlations

In this article we report the synthesis and magneto-structural characterization of two new copper(II) compounds with thiocyanato and methyl(2-pyridil) ketone oxime (mpkOH), namely [Cu(NCS)(mpkO)(mpkOH)] (1) and [Cu(µ-NCS)(NCS)(mpkOH)]n (2). Compound 1 is a mononuclear complex that crystallizes as discrete units. Conversely, compound 2 is a single equatorial-axial end-to-end thiocyanato bridged polymeric chain of Cu(II) with the oxime as a co-ligand. The coordination geometry around the Cu(II) centers is distorted square pyramidal for 1 and 2. The magnetic susceptibility data for 2 reveal weak intrachain antiferromagnetic coupling, with J value −0.74(3) cm−1 and g = 2.10(1). The application of computational tools to a binuclear model of 2 allowed us to unveil the structural basis that modulates the magnetic behavior of this type of thiocyanato-bridged Cu(II) chains. The results suggest that although small values of J are expected, the strongest ferromagnetic interactions can be obtained by including co-ligands that trigger a squared-based pyramidal-to-trigonal bipyramidal distortion of the coordination polyhedra.

Ferro- and Antiferromagnetic Interactions in Oxalato-Centered Inverse Hexanuclear and Chain Copper(II) Complexes with Pyrazole Derivatives.

Two novel copper(II) complexes of formulas {[Cu(4-Hmpz)4][Cu(4-Hmpz)2(µ3-ox-κ2O1,O2:κO2′:κO1′)(ClO4)2]}n (1) and {[Cu(3,4,5-Htmpz)4]2[Cu(3,4,5-Htmpz)2(µ3-ox-κ2O1,O2:κO2′:κO1′)(H2O)(ClO4)]2[Cu2(3,4,5-Htmpz)4(µ-ox-κ2O1,O2:κ2O2′,O1′)]}(ClO4)4·6H2O (2) have been obtained by using 4-methyl-1H-pyrazole (4-Hmpz) and 3,4,5-trimethyl-1H-pyrazole (3,4,5-Htmpz) as terminal ligands and oxalate (ox) as the polyatomic inverse coordination center. The crystal structure of 1 consists of perchlorate counteranions and cationic copper(II) chains with alternating bis(pyrazole)(µ3-κ2O1,O2:κO2′:κO1′-oxalato)copper(II) and tetrakis(pyrazole)copper(II) fragments. The crystal structure of 2 is made up of perchlorate counteranions and cationic centrosymmetric hexanuclear complexes where an inner tetrakis(pyrazole)(µ-κ2O1,O2:κ2O2′,O1′-oxalato)dicopper(II) entity and two outer mononuclear tetrakis(pyrazole)copper(II) units are linked through two mononuclear aquabis(pyrazole)(µ3-κ2O1,O2:κO2′:κO1′-oxalato)copper(II) units. The magnetic properties of 1 and 2 were investigated in the temperature range 2.0–300 K. Very weak intrachain antiferromagnetic interactions between the copper(II) ions through the µ3-ox-κ2O1,O2:κO2′:κO1′ center occur in 1 [J = −0.42(1) cm−1, the spin Hamiltonian being defined as H = −J∑S1,i · S2,i+1], whereas very weak intramolecular ferromagnetic [J = +0.28(2) cm−1] and strong antiferromagnetic [J’ = −348(2) cm−1] couplings coexist in 2 which are mediated by the µ3-ox-κ2O1,O2:κO2′:κO1′ and µ-ox-κ2O1,O2:κ2O2′,O1′ centers, respectively. The variation in the nature and magnitude of the magnetic coupling for this pair of oxalato-centered inverse copper(II) complexes is discussed in the light of their different structural features, and a comparison with related oxalato-centered inverse copper(II)-pyrazole systems from the literature is carried out.

Review of Zambia’s potential for more value addition to the downstream copper chain

Zambia copper industry has been in existence for over a century. The country contains most known reserves in Africa and holding about 6 percent known copper reserves in the world. Copper production plays a big role in the performance of the economy. Copper exports account for more than 70 per cent of total exports and 12 per cent of the country GDP. However, with the rich history of mining and copper reserves, studies have shown that Zambia still exports more than 70 per cent of her raw copper blister or copper anodes. Only 5 percent of copper cathodes produced consumed locally to further produce finished products such as copper rods and cables. The study will, therefore, focus on the potential that Zambia has to add value in the copper chain downstream. Specifically, the research focused on the downstream copper production and processing potential in respect of copper blister or anodes, copper cathodes, copper rod and cables. In addition the study reviewed whether the current mineral development policies and taxation are adequate to encourage value addition downstream and also investigate local and regional market for the final copper product. The research utilised statistical data available from Central Statistical Office, Bank of Zambia, Chambers of Mines, ZCCM-IH and international Copper Study groups to establish production, export copper and import of copper rods or cables. In addition to the above, research included visits to the only two copper fabricators ZAMEFA based in Luanshya and Neelkanth Cables Limited in Ndola. Using the statistical data collected and field visits to the fabrication industry, it was established that Zambia has a potential to add more value to its downstream copper chain by producing more than 1 million copper blister or cathodes from the available smelter facilities and though enhancement of policies and taxation incentives.

Synthesis of a rod-based porous coordination polymer from a nucleotide as a sequential chiral inductor

We report the two-step synthesis of a novel chiral rod-based porous coordination polymer (PCP). The chemical approach consists of the use of a previously prepared bis(ethylenediamine) copper monomer [Cu(en)]2(NO3)2 [where en = ethylenediamine] reacting with the cytidine 5′-monophosphate (CMP) nucleotide. The bis(ethylenediamine) copper compound—stabilized by axial coordination of nitrate counter-anions—reacts in the presence of sodium salt of CMP to yield right-handed copper(II) chains of P helicity with formula [Cu2(en)2(CMP)2]·5H2O (1). The axial coordination of the CMP2- ligands through the N3 and O2 sites (free nitrogen and carbonyl groups) of the cytosine nucleobase and oxygen atoms of phosphate moieties, ensure stabilization of the neutral chiral polymer. The supramolecular organization involves strong hydrogen bonding interactions to build supramolecular chains of the same helicity. The resulting PCP constitutes one of the few examples of CMP compounds exhibiting coordination involving both nucleobase and phosphate moieties, where a highly stable metal complex is used as precursor for the rational construction of rod-based hydrogen metal-organic frameworks (HMOFs). Furthermore, it shows the intrinsic capability of biomolecules to act as chiral transfer systems.

Global Electrification of Vehicles and Intertwined Material Supply Chains of Cobalt, Copper and Nickel

Electric vehicles (EVs) will be an important part of a low-carbon economy. Future EV adoption depends on overcoming multiple barriers, including charging infrastructure, sufficient electricity generation, and the availability of battery raw materials at acceptable costs, including cobalt, copper and nickel – which typically are co-produced. Various EV projections have been made, along with associated requirements for battery raw materials (demand). There have been separate assessments of the availability of raw materials (supply). However, integrated assessments of supply and demand and their interaction over time are lacking to support decision-making. Using a dynamic market model that reflects the co-produced nature of cobalt, copper and nickel production as well as recycling, we estimate global output of these three metals under different EV growth scenarios from 2020 to 2040. Results suggest that starting in 2025, replacement demand for battery raw materials becomes important. Thus, estimates for future material demand that consider only demands from new EVs are incomplete and misleading. EV deployment and associated increased demand for raw materials will have a greater impact on prices for cobalt than nickel and, in turn, for nickel than copper. High EV deployment scenarios will be difficult to achieve without larger supplies of copper, nickel and cobalt than forthcoming under the conditions modeled here, which anticipates a six-year time lag between a demand increase and the expansion of metal-production capacity. Shortening battery lifetimes and improving collection and recycling rates increase secondary supply, but the extent to which these factors support additional EV deployment is mixed.

Well-isolated pyrazine-bridged copper(II) chains: synthesis and magneto-structural analysis

A pair of well-isolated 1-D-QHAF compounds with the molecular formula [Cu(pz)(L)2(H2O)2](ClO4)2 with L = 3-Cl-4-hydroxypyridine (1) and 3-Br-4-hydroxypyridine (2) (catena-(diaqua-bis(3-chloro/bromo-4-pyridono-κO)(μ-pyrazine)copper(II) diperchlorate) were synthesized via slow-evaporation crystallization and characterized structurally and magnetically to develop magneto-structural correlations. Single-crystal X-ray diffraction at 120 K provided the structures of 1 and 2 which comprise six-coordinate Cu(II) pyrazine-bridged chains propagating parallel to the crystallographic a-axis in the triclinic space-group P-1. Chains are offset from each other in the c-direction by the bulk of L and along the dz2 axis occupied by a semi-coordinate water molecule engaged in hydrogen bonding with the perchlorate gegenion. Magnetic susceptibility experiments showed that 1 and 2 behave as quasi-Heisenberg 1-D-AFMs with J ≈ 8 K and no sign of 3 D ordering down to 1.8 K. Aspects of crystal engineering are addressed to understand the potential to design systems with desired magnetic properties in light of comparisons with a variety of pyrazine-bridged chains already in the literature. The effect of L and the general structural scaffold are investigated to this end. Powder X-Band EPR experiments were performed to determine the electronic environment of the Cu(II) ion and average g-factor. The pyrazine-bridged chains in 1 with the AFM electronic spins represented as glowing arrows.

Origin of up-up-down-down magnetic order in Cu2GeO4

We use density-functional band-structure calculations to explore the origin of the up-up-down-down (UUDD) magnetic order in Cu$_2$GeO$_4$ with the frustrated $J_1-J_2$ spin chains coupled into layers within the spinel-like crystal structure. In contrast to earlier studies, we find that the nearest-neighbor coupling $J_1$ may be negligibly small, owing to a nearly perfect compensation of the ferromagnetic direct exchange and antiferromagnetic superexchange. Under this condition, weak symmetric anisotropy of the exchange couplings gives rise to the UUDD order observed experimentally and also elucidates the non-trivial ordering pattern between the layers, whereas a small Dzyaloshinsky-Moriya interaction causes a spin canting that may generate local electric polarization. We argue that the buckling of the copper chains plays a crucial role in the suppression of $J_1$ in Cu$_2$GeO$_4$ and sets this compound apart from other $J_1-J_2$ chain magnets.

Synthesis, crystal structures and magnetic properties of picolinate-bridged copper(II) chains

The paper reports the synthesis, crystal structures, and magnetic properties of two copper(II) coordination polymers, Cu2(L1)4 (1) and Cu3(L2)6 (2), based on rigid ethynylene-bridged ditopic ligands containing one picolinate subunit (L1 = 5-(pyridin-3-ylethynyl)picolinate anion; L2 = 5-((4-(methoxycarbonyl)phenyl)ethynyl)picolinate anion). Both 1 and 2 have a chain structure. In 1, the repeating unit in the chain is a doubly bridged picolinate dicopper(II) complex, whereas 2 is built upon trimeric units where the Cu2+ ions are also connected by double picolinate bridges. Both compounds exhibit antiferromagnetic interactions in the solid state. The magnetic properties of 1 and 2 were analyzed in terms of simple dimer (H = –2JSCuSCu) and linear trimer [H = –2J(SCu1SCu2+SCu2SCu1)] models, respectively, neglecting the intermolecular interactions between the polynuclear units. The values of the exchange coupling parameters were J = −0.59 and J = –0.30 cm−1 for 1 and 2, respectively.

Development of a Millimeter-Wave Electron-Spin-Resonance Measurement System for Ultralow Temperatures and Its Application to Measurements of Copper Pyrazine Dinitrate

We have developed a millimeter-wave electron-spin-resonance (ESR) measurement system using a 3He-4He dilution refrigerator for the ultralow-temperature range below 1 K. The currently available frequency range is 125–130 GHz. This system is based on a Fabry-Perot-type resonator (FPR) that is composed of two mirrors. The frequency can be changed by adjusting the distance between the mirrors using a piezoelectric actuator installed at the bottom of the resonator. A homodyne detection system with an InSb detector is built into the low-temperature section of the 3He-4He dilution refrigerator; this system provides high sensitivity. Using this system, we performed ESR measurements on a Heisenberg quantum-spin chain—copper pyrazine dinitrate, Cu(C4H4N2)(NO3)2—over the temperature range from 6.6 down to 0.25 K. The ESR lines change continuously with decreasing temperature. Our results suggest that the ESR spectrum of copper pyrazine dinitrate may be useful as a temperature sensor for the very low-temperature range.

Participation of copper ions in formation of alginate conditioning layer: Evolved structure and regulated microbial adhesion

Antifouling function of copper-based layers is usually gained through the release of cuprous or copper ions to damage most fouling species. In this research the intervening mechanisms of copper ions in formation of simplified conditioning layer comprising marine polysaccharide alginate and subsequent adhesion of typical marine bacteria and algae were studied. Fast interaction of Cu2+ with alginate with the formation of copper alginate multimers was observed for the first time by negative-staining electron microscopy. Interconnecting chains of alginate and copper alginate upon adsorption on silicon wafer and tangled structure of the conditioning layer were further characterized by atomic force microscopy. Adhesion testing showed that consumption of copper ions by their linking with alginate in incubation solutions resulted in mitigated toxicity of the ions to the microorganisms Bacillus sp., Chlorella pyrenoidosa and Phaeodactylum tricornutum. The results would give insight into understanding and regulating the formation of conditioning layer for desired antifouling performances.

Controlled and Reversible Stepwise Growth of Linear Copper(I) Chains Enabled by Dynamic Ligand Scaffolds.

Reversible stepwise chain growth in linear CuI assemblies can be achieved by using the dynamic, unsymmetric naphthyridinone-based ligand scaffolds L1 and L2. With the same ligand scaffolds, the length of the linear copper chain can be varied from two to three and four copper atoms, and the nuclearity of the complex is easily controlled by the stepwise addition of a CuI precursor to gradually increase the chain length, or by the reductive removal of Cu atoms to decrease the chain length. This represents a rare example of a stepwise controlled chain growth in extended metal atom chains (EMACs). All complexes are formed with excellent selectivity, and the mutual transformations of the complexes of different nuclearity were found to be fast and reversible. These unusual rearrangements of metal chains of different nuclearities were achieved by a stepwise "sliding" movement of the naphthyridinone bridging fragment along the metal chain.

Controlled and Reversible Stepwise Growth of Linear Copper(I) Chains Enabled by Dynamic Ligand Scaffolds

AbstractReversible stepwise chain growth in linear CuI assemblies can be achieved by using the dynamic, unsymmetric naphthyridinone‐based ligand scaffolds L1 and L2. With the same ligand scaffolds, the length of the linear copper chain can be varied from two to three and four copper atoms, and the nuclearity of the complex is easily controlled by the stepwise addition of a CuI precursor to gradually increase the chain length, or by the reductive removal of Cu atoms to decrease the chain length. This represents a rare example of a stepwise controlled chain growth in extended metal atom chains (EMACs). All complexes are formed with excellent selectivity, and the mutual transformations of the complexes of different nuclearity were found to be fast and reversible. These unusual rearrangements of metal chains of different nuclearities were achieved by a stepwise “sliding” movement of the naphthyridinone bridging fragment along the metal chain.

In situ surface assembly of core-shell TiO2-copper(I) cluster nanocomposites for visible-light photocatalytic reduction of Cr(VI)

1D loop chain copper(I) cluster, [Cu2I2L2]n, can be obtained based upon 9-(3-phenylselanyl-2-phenylselanylmethylpropyl)anthracene (L) and CuI. A facile in situ surface assembly strategy was designed to construct polymeric [Cu2I2L2]n on the surface of TiO2 nanoparticles. The visible-light photocatalytic property of core-shell TiO2-[Cu2I2L2]n was confirmed by effective reduction of aqueous chromium(VI), showing a clear correlation to optical absorption (Eg=2.8eV). The key points of this strategy include high reactivity between copper(I) and soft selenium atom, efficient charge-transfer through polymeric cluster shell, and visible-light photoactivity of copper(I) halogen clusters.

Two new POM-based compounds containing a linear tri-nuclear copper(II) cluster and an infinite copper(II) chain, respectively

Abstract Using the pendent organic ligand 1-butyl-1H-(1,3,4)triazole (btz), two new polyoxometalate (POM)-based compounds, [Cu3(btz)6(H2O)4(H3P2W18O62)2]·6H2O (1) and [Cu2(btz)(tz)(H2O)2(SiMo12O40)]·5H2O (2) (tz=1H-(1,3,4)triazole), have been synthesized under hydrothermal conditions. In compound 1, three CuII ions are fused by six btz ligands to form a linear tri-nuclear CuII cluster, with water as bridging molecules. Two Wells-Dawson anions offer two terminal O atoms to link two apical CuII atoms of this tri-nuclear cluster. In compound 2, the btz and tz molecules connect CuII ions to construct an infinite CuII chain still with water molecules as bridges. The adjacent chains are linked by one type of POM anions to build a 2D grid-like layer. Considering the long-range coordinative Cu–O bonds, the other types of POM anions connect adjacent layers to form a 3D framework. The electrochemical and photocatalytic properties of compounds 1 and 2 were also studied.

A 1-D alternating copper(II) chain based on three acetate-bridging modes: synthesis, crystal structure, DNA binding and magnetic properties

A new 1-D alternating copper(II) polymer, [Cu2(L)(OAc)4]n (1) (L = 5-chloro-2-(pyridine-2-yl)benzo[d]thiazole), has been isolated and characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy, and magnetic susceptibility. The complex crystallized in the triclinic space group P-1, a = 8.2277(16) Å, b = 9.4233(19) Å, c = 15.831(3) Å, α = 103.38(3)°, β = 99.95(3)°, γ = 92.70(3)°, V = 1171.3(4) Å3, and comprises a 1-D polymer linked by three kinds of acetate-bridging modes in an alternating manner. UV–visible and fluorescence spectra revealed that 1 is bound to CT-DNA in a partial intercalation mode. Through gel electrophoresis assays, 1 displayed an efficient oxidative cleavage activity on supercoiled plasmid DNA (pUC19) in the presence of H2O2. Magnetic measurements were performed from 2 to 300 K, and the experimental results were satisfactorily reproduced with J1 = –160 ± 20 cm−1, J2 = 5.8 ± 0.2 cm−1, zJ′ = 0.381 ± 0.005 cm−1 and g = 2.1, showing antiferromagnetic coupling between Cu1 and Cu1i, ferromagnetic exchange between Cu2 and Cu2ii, and a weak ferromagnetic molecular field correction accounting for all interspecies interactions.