Wire Structures Research Articles

Features of the integration of two-layer metal knitwear made of titanium nickelide during the replacement of a thoracoabdominal defect in the experiment

The aim of investigation was to study experimentally the morphological features of tissue integration of two-layer titanium nickelide (TiNi) knitwear when replacing thoracoabdominal defects.Materials and methods. The experiments were carried out on 40 Wistar rats. The experimental animals were divided into two comparison groups: in Group A (n = 20) the defect was replaced using a two-layer knitted tape made of TiNi, in Group B (n = 20) a polypropylene mesh implant was used. The technique of the operation and the peculiarities of keeping the animals did not differ. Animals were taken out after 14, 30, 60 and 90 days of experiment. The macroscopic structural features at the site of implant fixation to tissues and at the sites of contact with underlying organs were studied, and the inflammatory process was assessed. The histological and electron microscopic study was carried out with an assessment of the features of tissue integration through the mesh structure of knitwear.Results. Thirty days after the surgery in four cases of Group B the appearance of the chest wall deformation at the site of implant fixation was noted, in one case the deformation site was located along the lateral edge of the abdominal wall. Among the animals of Group A no such changes were recorded. The histological and electron microscopy examination revealed that the porous structure of the TiNi wire, as well as the biomechanical and biochemical properties of the two-layer metal knitwear, ensure optimal integration of the endoprosthesis in the body tissues, forming an elastic frame close to natural. In Group B, on the contrary, the reaction of the body caused by the implanted polypropylene prosthesis was characterized by more pronounced fibrosis, and tissue integration through the mesh structure of the implant was not observed.Conclusion. Two-layer TiNi knitwear in the replacement of complex structures of the thoracoabdominal zone showed promising results, which opens up prospects for further clinical research.

Electromigration Reliability of Barrierless Ruthenium and Molybdenum for Sub-10 nm Interconnection

Cu interconnects suffer from increased resistance and poor reliability at a sub-10 nm width. Ru and Mo have been highlighted recently as the next interconnection material candidate due to their various advantages over Cu; they have lower resistance than Cu at sub-10 nm, do not diffuse into SiO2, and are etchable. Here, we evaluated the electromigration (EM) reliability of Ru and Mo to confirm their feasibility for the next-generation interconnection. The activation energy for EM failure is calculated by measuring the mean time to failure (MTTF) of film and wire structures while factoring in temperature increases with thermal coefficient of resistance (TCR) measurements. In addition, we investigate the EM properties in terms of resistivity-increasing parameters that originate from geometry and additional fabrication processes. Furthermore, we evaluate the EM performance in terms of electrochemical potential. Our findings confirm the feasibility of Ru as a promising candidate for next-generation interconnection applications, providing enhanced reliability compared to conventional Cu interconnects.

Numerical simulation and experimental study on metallographic structure characteristics of melting trace caused by overcurrent fault of copper wire

The microscopic characteristics of melting trace caused by copper wire fault are an important basis for the physical evidence identification of electrical fires. Metallography is an important method in electrical fire research, and computer-aided quantitative analysis on metallographic structure is common in materials aspect. In this study, the metallographic structure and phase composition characteristics of melting trace caused by overcurrent fault were explored with the aid of a metallographic microscope and an X-ray diffractometer (XRD). The results show that the grains are mainly slender dendritic and columnar crystals when the current is 128 A, while they are coarse dendritic and cellular crystals when the current is greater than 192 A; the average grain diameter of melting trace of copper wire grows with the increase in current. The main phases of melting trace caused by overcurrent fault of copper wire are α-Cu base and Cu2O, and the new phases Cu4Si and Cu2Mg are formed when the current is higher than 160 A. In addition, the solidification process of metallographic structure of copper wire under different currents was simulated by the Procast software. It is found that the simulation results are basically in agreement with the experimental data, which suggests that this model can effectively predict the microstructure characteristics of melting trace of copper wire under different currents. The research results can provide a sound basis for the physical evidence identification of electrical fire and improve the accuracy and scientificity of electrical fire investigation.

Influence of Nb Morphology on the Structure and Properties of High Strength and High Conductivity Cu-Nb Composite Wires

Influence of Nb Morphology on the Structure and Properties of High Strength and High Conductivity Cu-Nb Composite Wires

A Technology for Bonding Cu Wires with Cu Pads: Structure and Electrical Fatigue Mechanism of Fine Micro-alloyed Cu Wires

A Technology for Bonding Cu Wires with Cu Pads: Structure and Electrical Fatigue Mechanism of Fine Micro-alloyed Cu Wires

Individual Effects of Alkali Element and Wire Structure on Metal Transfer Process in Argon Metal-Cored Arc Welding.

This study aimed to clarify the effect of wire structure and alkaline elements in wire composition on metal transfer behavior in metal-cored arc welding (MCAW). A comparison of metal transfer in pure argon gas was carried out using a solid wire (wire 1), a metal-cored wire without an alkaline element (wire 2), and another metal-cored wire with 0.084 mass% of sodium (wire 3). The experiments were conducted under 280 and 320 A welding currents, observed by high-speed imaging techniques equipped with laser assistance and bandpass filters. At 280 A, wire 1 showed a streaming transfer mode, while the others showed a projected one. When the current was 320 A, the metal transfer of wire 2 changed to streaming, while wire 3 remained projected. As sodium has a lower ionization energy than iron, the mixing of sodium vapor into the iron plasma increases its electrical conductivity, raising the proportion of current flowing through metal vapor plasma. As a result, the current flows to the upper region of the molten metal on the wire tip, with the resulting electromagnetic force causing droplet detachment. Consequently, the metal transfer mode in wire 3 remained projected. Furthermore, weld bead formation is the best for wire 3.

Thermal-hydraulic analysis of He–Xe gas mixture in 2×2 rod bundle wrapped with helical wires

Gas-cooled space reactor, which adopts He–Xe gas mixture as working fluid, is a better choice for megawatt power generation. In this paper, thermal-hydraulic characteristics of He–Xe gas mixture in 2 × 2 rod bundle wrapped with helical wires is numerically investigated. The velocity, pressure and temperature distribution of the coolant are obtained and analyzed. The results show that the existence of helical wires forms the vortexes and changes the velocity and temperature distribution. Hot spots are found at the contact corners between helical wires and fuel rods. The highest temperature of the hot spots reach 1600K, while the mainstream temperature is less than 400K. The helical wire structure increases the friction pressure drop by 20%–50%. The effect extent varies with the pitch and the number of helical wires. The helical wire structure leads to the reduction of Nusselt number. Comparing thermal-hydraulic performance ratios (THPR) of different structures, the THPR values are all less than 1. It means that gas-cooled space reactor adopting helical wires could not strengthen the core heat removal performance. This work provides the thermal-hydraulic design basis for He–Xe gas cooled space nuclear reactor.

Influence of pitting corrosion parameters on the residual fatigue life of a steel cable

ABSTRACT Corrosion wastage is a significant factor that leads to load bearing capacity degradation of cable steel wire (CSW) structures. This paper aims to study the influence of pitting corrosion parameters on residual fatigue life (RFL) of a steel cable, so as to fit a series of formulas to predict the RFL of steel cables directly and quickly. Firstly, single and double pitting corroded CSWs are modelled by FEM. Secondly, stress concentration factors (SCFs) and residual fatigue lives (RFLs) of the corroded CSWs are calculated. Finally, calculation formulas of SCFs and RFLs of the CSWs with various pit depths and widths are fitted. The results show that SCF increases with the increase of pit depth and decreases with the increase of pit width. RFL decreases with the increase of pit depth and increases with the increase of pit width. SCF and RFL have nothing to do with the amount of corrosion pits, but only affected by the depth of the deepest pit.

Superhydrophobic and Conductive Wire Membrane for Enhanced CO2 Electroreduction to Multicarbon Products

AbstractGas‐liquid‐solid triple‐phase interfaces (TPI) are essential for promoting electrochemical CO2 reduction, but it remains challenging to maximize their efficiency while integrating other desirable properties conducive to electrocatalysis. Herein, we report the elaborate design and fabrication of a superhydrophobic, conductive, and hierarchical wire membrane in which core–shell CuO nanospheres, carbon nanotubes (CNT), and polytetrafluoroethylene (PTFE) are integrated into a wire structure (designated as CuO/F/C(w); F, PTFE; C, CNT; w, wire) to maximize their respective functions. The realized architecture allows almost all CuO nanospheres to be exposed with effective TPI and good contact to conductive CNT, thus increasing the local CO2 concentration on the CuO surface and enabling fast electron/mass transfer. As a result, the CuO/F/C(w) membrane attains a Faradaic efficiency of 56.8 % and a partial current density of 68.9 mA cm−2 for multicarbon products at −1.4 V (versus the reversible hydrogen electrode) in the H‐type cell, far exceeding 10.1 % and 13.4 mA cm−2 for bare CuO.

Superhydrophobic and Conductive Wire Membrane for Enhanced CO2 Electroreduction to Multicarbon Products.

Gas-liquid-solid triple-phase interfaces (TPI) are essential for promoting electrochemical CO2 reduction, but it remains challenging to maximize their efficiency while integrating other desirable properties conducive to electrocatalysis. Herein, we report the elaborate design and fabrication of a superhydrophobic, conductive, and hierarchical wire membrane in which core-shell CuO nanospheres, carbon nanotubes (CNT), and polytetrafluoroethylene (PTFE) are integrated into a wire structure (designated as CuO/F/C(w); F, PTFE; C, CNT; w, wire) to maximize their respective functions. The realized architecture allows almost all CuO nanospheres to be exposed with effective TPI and good contact to conductive CNT, thus increasing the local CO2 concentration on the CuO surface and enabling fast electron/mass transfer. As a result, the CuO/F/C(w) membrane attains a Faradaic efficiency of 56.8 % and a partial current density of 68.9 mA cm-2 for multicarbon products at -1.4 V (versus the reversible hydrogen electrode) in the H-type cell, far exceeding 10.1 % and 13.4 mA cm-2 for bare CuO.

Structure and Mechanical Properties of the NiTi Wire Joined by Laser Welding.

Joining wires made of NiTi alloys with shape memory effect and pseudoelasticity causes many technical and structural problems. They result from unwanted phase interactions that occur in high temperatures and negatively affect the characteristics of these materials. Such obstacles are challenging in terms of welding. Hence, an attempt was made to join NiTi wires via an economical and reliable basic laser welding technique which does not require complicated equipment and gas protection. The parameters such as spot diameter and pulse time were constant and only the laser power, calculated as a percentage of the total power, was optimized. The wires were parallelly connected with overlapping seam welds 10 mm long. The welds were examined regarding their microstructure, chemical and phase composition, reversible martensitic transformation, microhardness, and pseudoelasticity. The obtained results showed that the joint was completed at the 12-14% power. The weld revealed good quality with no voids or pores. As the laser power increased, the microhardness rose from 282 (for 4%) to 321 (for 14%). The joint withstood the stress-inducing reversible martensitic transformation. As the transformation was repeated cyclically, the stress value decreased from 587 MPa (initial wire) to 507 MPa (for the 14% power welded wire).

Integrated Model for Lightning Strikes on a Tall Structure: Application to a Wind Turbine System

This article presents an integrated model of the lightning channel and tall structure on the ground for lightning analysis, by considering their interaction. An extended distributed circuit is proposed for modeling the lightning channel, by including the dynamic behavior of the corona sheath. The nonlinear, nonuniform, and time evolution characteristics of the lightning channel are taken into account. Meanwhile, the wire structure on the ground is modeled with the partial element equivalent circuit method. A lumped voltage source is introduced to ensure an “undisturbed” current waveform at the attachment point. A procedure is provided to determine this voltage source in a nonlinear circuit. The proposed model is verified with the experimental data of lightning-striking tall towers. This model then is applied to simulate lightning surges on a wind turbine system. A comparison with the simple current source model is made. Significant oscillation is found with the simple current source model, which is not in correspondence with the observation result under natural lightning.

Lightning Protection With a Differentiated Configuration of Arresters in a Distribution Network

When concerning the installation and operation costs, it is always desirable to protect an overhead distribution network with a limited quantity of surge arresters (SAs). This paper presents a novel procedure for designing differentiated protection against lightning, by identifying appropriate positions for those SAs on the overhead line. Rather than the traditional flashover rate of a whole line, indices in terms of flashover numbers at individual poles and associated with possible stroke locations are introduced in this paper. Based on these flashover indices, a differentiated configuration of SAs can be identified using a selection strategy. After several rounds of selection, a differentiated SA protection scheme can be obtained, given by a pre-set quantity of SAs. In this procedure, a simplified probability-based approach is proposed to determine the flashover indices. By comparing the traditional Monte Carlo method, this approach can achieve a 10-fold increase in computational efficiency with reasonable accuracy. Two different selection strategies are introduced in this paper. Compared with the selection strategy using the flashover indices at individual poles, the selection strategy based on a group of poles is recommended because it yields a configuration with better lightning performance with the same quantity of SAs. This design procedure is applied to practical distribution networks with a shield wire and nearby structures. The influence of grounding impedance, a shield wire, and nearby structures is addressed. Finally, a generalized step-by-step procedure is provided to assist in a differentiated SA protection design.

Analyses for simulation-based solution of fluid-structure interaction in percutaneous coronary intervention

Fluid-structure interaction (FSI) analysis is of great significance for the clinical practice of percutaneous coronary intervention (PCI). In this study the finite element method (FEM) model of Y-shaped coronary artery is established and the solution methodology of FSI analysis is presented in detail, and then the FSI analyses are performed to get quantities of interest by analyzing the three main effect factors of PCI, thereby to get preferred intervention pattern. The formula to calculate the coefficient of fluctuation δ, is proposed and employed to characterize the oscillation properties of the guide wire (GW) structure. A total of 48 different working condition cases have been simulated numerically using the established method, and a comprehensive analysis on the comparison of variables with different effect factors has been presented. It has been shown that the oscillation phenomena of blood flow force and displacement are found; and, for vascular stenosis, the phenomenon of recirculation is also found for all of the cases at the bifurcation owing to the existence of plaque. For initial observations, the main branch (MB) entry means seems to be one good means, which can be used for initial detection of vascular stenosis or obstruction. For vascular stenosis, three comparisons are made and discussed, and the variation laws can be used to give application guidance. In addition, a trial test has also been performed to indirectly verify the reliability of the simulation results. This work can provide insights useful for the control and setting of catheter/GW operation in PCI, especially for surgical assisted robot.

A flexible retinal device with CMOS smart electrodes fabricated on parylene C thin-film and bioceramic substrate

We developed implementation technologies for artificial vision devices compatible with suprachoroidal transretinal stimulation. We aimed to develop a device that can be safely implanted in the sclera of the eye for a long period. Using parylene C and bioceramics as biocompatible base materials, we realized a device with high in vivo safety by making the device structure flexible and reducing the wires of control signals. We successfully created a prototype device that combines a flexible wire structure based on a parylene C thin film with a wire-saving CMOS smart electrode structure based on CMOS integrated circuits. We conducted in vitro and in vivo experiments to confirm their performances. The immersion test confirmed that the device could work normally for four days. Furthermore, in the in vivo experiments using rats, we successfully measured evoked potentials in the brain induced by the stimulation current using the device.

Biometric authentication security enhancement under quantum dot light-emitting diode display via fingerprint imaging and temperature sensing

We improved biometric authentication security using dual recognition based on fingerprint image detection and skin-temperature-change sensing under quantum dot light-emitting diode (QLED) displays. QLEDs are more advantageous than organic light-emitting diodes (OLEDs) in terms of the contrast classification of patterns such as those in fingerprint recognition, owing to their narrow full-width-half-maximum. In this work, scattered, transmitted, and reflected light was captured from the top of the QLED, improving the digital luminance by 25%, as compared with that of OLEDs, because the electroluminescence spectra of the QLED were sustained, whereas those of the OLED were distorted by the generated noise peaks. A QLED with eight apertures sized up to tens of micrometers, mimicking the actual wiring structure of commercialized smartphones, was implemented to detect human fingerprints. The QLED using reduced graphene oxide as the temperature sensor detected temperature changes instantaneously upon finger touch, showing a 2% temperature response based on the human body temperature; however, the temperature change was less than 0.1% for spoof fingerprints printed on paper. Thus, this study successfully enhanced biometric authentication security, through fingerprint recognition based on image sensing using an optical system with micrometer-sized apertures and skin-temperature detection under QLED displays.

On the causes of electrothermal destruction of fiber-optic communication lines placed on the structures of AC overhead wires

The paper analyses the impact of the electromagnetic field of an alternating current catenary section on a fiber-optic cable suspended on the structures of the catenary system or on the overhead wires of the Centralised Traffic Control (CTC). Based on this calculation, conclusions have been made about the negative impact of alternating current electric fields with high vorticity.

A novel hierarchical-based simulation method for refined calculation of Litz wire structure

A novel hierarchical-based simulation method for refined calculation of Litz wire structure

Long and oriented graphene nanoribbon synthesis from well-ordered 10,10'-dibromo-9,9'-bianthracene monolayer on crystalline Au surfaces.

Bottom-up synthesis on metal surfaces has attracted attention for the fabrication of graphene nanoribbons (GNRs) with atomically-precise chemical structures to realize novel electronic devices. However, control of length and orientation on surfaces during GNR synthesis is difficult, thus, achieving longer and aligned GNR growth is a significant challenge. Herein, we report GNR synthesis from a well-ordered dense monolayer on Au crystalline surfaces for long and oriented GNR growth. Scanning tunneling microscopy showed that 10,10'-dibromo-9,9'-bianthracene (DBBA) precursors deposited on Au(111) at room temperature self-assembled into a well-ordered dense monolayer, and the straight molecular wire structure was formed where Br atoms in each precursor were adjacent along the wire axis. The DBBAs in the monolayer were found to be hardly desorbed from the surface under subsequent heating and efficiently polymerize along with the molecular arrangement, resulting in more long and oriented GNR growth compared to the conventional growth method. The result is attributed to be suppression of random diffusion and desorption of the DBBAs on the Au surface during polymerization due to the densely-packed DBBA structure. Additionally, an investigation of the effect of the Au crystalline plane on the GNR growth revealed further anisotropic GNR growth on Au(100) compared to Au(111) due to the stronger interactions of DBBA with Au(100). These findings provide fundamental knowledge for controlling GNR growth from a well-ordered precursor monolayer to achieve more long and oriented GNRs.

A novel hierarchical-based simulation method for refined calculation of Litz wire structure

A novel hierarchical-based simulation method for refined calculation of Litz wire structure