Electrical Connections Research Articles

Interconnecting EDOT-Based Polymers with Native Lignin toward Enhanced Charge Storage in Conductive Wood.

The 3D micro- and nanostructure of wood has extensively been employed as a template for cost-effective and renewable electronic technologies. However, other electroactive components, in particular native lignin, have been overlooked due to the absence of an approach that allows access of the lignin through the cell wall. In this study, we introduce an approach that focuses on establishing conjugated-polymer-based electrical connections at various length scales within the wood structure, aiming to leverage the charge storage capacity of native lignin in wood-based energy storage electrodes. We demonstrate that poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) PEDOT/PSS, integrated within the cell wall lumen, can be interfaced with native lignin through the wood cell wall through in situ polymerization of a water-soluble S-EDOT monomer. This approach increases the capacitance of the conductive wood to 315 mF cm-2 at a scan rate of 5 mV s-1, which is seven and, respectively, two times higher compared to the capacitance of conductive wood made with the single components PEDOT/PSS or S-PEDOT. Moreover, we show that the capacitance is contributed by both the electroactive polymers and native lignin, with native lignin accounting for over 70% of the total charge storage capacity. We show that accessing native lignin through in situ creation of electrical interconnections within the wood structure offers a pathway toward sustainable, wood-based electrodes with improved charge-storage capacity for applications in electronics and energy storage.

Views and experiences of young people on using mHealth platforms for sexual and reproductive health services in rural low-and middle-income countries: A qualitative systematic review.

In low- and middle-income countries (LMICs), reproductive health programs use mobile health (mHealth) platforms to deliver a broad range of SRH information and services to young people in rural areas. However, young people's experiences of using mobile phone platforms for SRH services in the rural contexts of LMICs remains unexplored. This review qualitatively explored the experiences and perceptions of young people's use of mobile phone platforms for SRH information and services. This qualitative evidence synthesis was conducted through a systematic search of online databases: Medline, Embase, CINAHL, PsycInfo and Scopus. We included peer reviewed articles that were conducted between 2000 to 2023 and used qualitative methods. The methodological quality of papers was assessed by two authors using Grading of Recommendations, Assessment, Development and Evaluation (GRADE) and Confidence in Evidence from Reviews of Qualitative research (CERQual) approach with the identified papers synthesized using a narrative thematic analysis approach. The 26 studies included in the review were conducted in a wide range of LMIC rural settings. The studies used seven different types of mHealth platforms in providing access to SRH information and services on contraception, family planning, sexually transmitted infections (STIs) and human immunodeficiency virus (HIV) education. Participant preferences for use of SRH service platforms centred on convenience, privacy and confidentiality, as well as ease and affordability. High confidence was found in the studies preferencing text messaging, voice messaging, and interactive voice response services while moderate confidence was found in studies focused on phone calls. The overall constraint for platforms services included poor and limited network and electricity connectivity (high confidence in the study findings), limited access to mobile phones and mobile credit due to cost, influence from socio-cultural norms and beliefs and community members (moderate confidence in the study findings), language and literacy skills constraints (high confidence in the study findings). The findings provide valuable information on the preferences of mHealth platforms for accessing SRH services among young people in rural settings in LMICs and the quality of available evidence on the topic. As such, the findings have important implications for health policy makers and implementers and mHealth technology platform developers on improving services for sustainable adoption and integration in LMIC rural health system.

3D package thermal analysis and thermal optimization

3D packaging mainly uses TSVs (Through Silicon via) to vertically interconnect multiple chips, achieving the purpose of signal transmission and electrical connection. As a popular advanced packaging method, its research is of great significance. Although stacked chips can achieve stronger performance in smaller spaces, they can also cause a series of reliability issues, among which thermal stress and warping due to differences in the thermal expansion coefficients of materials can even lead to chip failure. Therefore, it is highly valuable to simulate and analyze the entire 3D packaging model.In this study, the thermal stress and deformation of the whole three-dimensional package model were simulated by finite element analysis. The results showed that there were significant stress and deformation effects at the joint of the TSV structure at normal temperature, and the stress and deformation reached 209.99MPa and 0.0018519mm, respectively. After that, the temperature of the double-sided package system containing 3D package under electrothermal coupling conditions was optimized by heat dissipation design, which verified the ‘quantity first’ scheme of heat dissipation fins and reduced the temperature by 40%.

Flat-Knitted Double-Tube Structure Capacitive Pressure Sensors Integrated into Fingertips of Fully Fashioned Glove Intended for Therapeutic Use

A therapeutic glove, which enables medical non-professionals to perform physiotherapeutic gripping and holding movements on patients, would significantly improve the healthcare situation in physiotherapy. The glove aims to detect the orthogonal pressure load and provide feedback to the user. The use of textile materials for the glove assures comfort and a good fit for the user. This, in turn, implies a textile realization of the sensor system in order to manufacture both the glove and the sensor system in as few process steps as possible, using only one textile manufacturing technique. The flat knitting technology is an obvious choice here. The aim of the study is to develop a textile capacitive pressure sensor that can be integrated into the fingertips of a glove using flat knitting technology and to evaluate its sensor properties with regard to transmission behavior, hysteresis and drift. It was shown that the proposed method of a flat knitting sensor fabrication is suitable for producing both the sensors and the glove in one single process step. In addition, the implementation of an entire glove with integrated pressure sensors, including the necessary electrical connection of the sensor electrodes via knitted conductive paths in three fingers, was successfully demonstrated.

Construction of pumped storage power stations among cascade reservoirs to support the high-quality power supply of the hydro-wind-photovoltaic power generation system

Multi-energy complementary technology has become one of the core elements to promote the structural transformation of global energy and cope with climate change. Faced with the rapid growth of wind power and photovoltaic, the uncertainty of its power generation will increase further, and it is urgent to explore more types of flexible regulation power sources to compensate for them. The construction of pumped storage power stations among cascade reservoirs is a feasible way to expand the flexible resources of the multi-energy complementary clean energy base. However, this way makes the hydraulic and electrical connections of the upper and lower reservoirs more complicated, which brings more uncertainty to the power generation. Hence, to support the high-quality power supply, this research explores the complementary characteristics of the clean energy base building different types of pumped storage power stations, and recognizes the efficient operation intervals of the giant cascade reservoir. First, a multi-dimensional uncertainty evaluation system is proposed to elaborate on the typical output scenarios of wind power and photovoltaic in more detail. Next, based on different utilization principles of wind power and photovoltaic, the multi-energy complementary operation models of the hydropower-wind-PV hybrid system, the hydropower-wind-PV hybrid system including pump stations, and the hydropower-wind-PV hybrid system including reversible hydro units are established. Further, a multi-dimensional scenarios random combination method is applied to investigate the response relationship between the operation parameters of the key reservoir and the operation indicators of the clean energy base. Finally, these above methods have been practiced in the clean energy base in the upper Yellow River basin. The main results of the research are as follows: (1) when the power output of wind-PV plants is high, the absorption rates of wind power and photovoltaic increase by 36% and 12% respectively, in hydropower-wind-PV hybrid systems with reversible hydro units and with pump stations, compared to the hydropower-wind-PV hybrid system; (2) when the power output of wind-PV plants is high, the load loss rates of the transmission channel decrease by 28.57% and 14.28% respectively, in hydropower-wind-PV hybrid systems with reversible hydro units and with pump stations, compared to the hydropower-wind-PV hybrid system; (3) for the hydropower-wind-PV hybrid system including reversible hydro units, the comprehensive utilization flow of the key reservoir respectively maintain 500-800 m3/s and 1000-1200 m3/s in the max scenario and min scenario of wind power and photovoltaic, which is beneficial to the efficient absorption of new energy and high-quality power transmission; (4) for the hydropower-wind-PV hybrid system including pump stations, the comprehensive utilization flow of the key reservoir should respectively keep 500-750 m3/s and 950-1100 m3/s in the max scenario and min scenario of wind power and photovoltaic.

Bio-Inspired Core-Shell Structured Electrode Particles with Protective Mechanisms for Lithium-Ion Batteries.

Lithium-ion batteries (LIBs), as predominant energy storage devices, are applied to electric vehicles, which is an effective way to achieve carbon neutrality. However, the major obstructions to their applications are two dilemmas: enhanced cyclic life and thermal stability. Taking advantage of bio-inspired core-shell structures to optimize the self-protective mechanisms of the mercantile electrode particles, LIBs can improve electrochemical performance and thermal stability simultaneously. The favorable core-shell structures suppress volume expansion to stabilize electrode-electrolyte interfaces (EEIs), mitigate direct contact between the electrode material and electrolyte, and promote electrical connectivity. They possess wide operating temperatures, high-voltage resistance, and inhibit short circuits. During cycling, the cathode and anode generate a cathode-electrolyte interface (CEI) and a solid-electrolyte interface (SEI), respectively. Applying multitudinous coating approaches can generate multifarious bio-inspired core-shell structured electrode particles, which is helpful for the generation of the EEIs, self-healing the surface cracks, and maintaining the structural integrities of electrodes. The protected shells act as barriers to minimize unwanted side reactions and enhance thermal stability. These in-depth understandings of the bio-inspired evolution for electrode particles can inspire further enhancements in LIB lifetime and thermal safety, especially for bio-inspired core-shell structured electrodes possessing high-performance protective mechanisms.

Acoustic Tunable Battery‐Free Implants Based on Sustainable Triboelectric Nanogenerators With Metal‐Polymer Intermixing Layers

AbstractUltrasound‐driven triboelectric nanogenerators (US‐TENGs) offer an innovative solution for transcutaneous power transfer, with the potential to enable battery‐free, permanently implantable electronics. However, research to date has primarily demonstrated only fragmentary functionalities for these applications. This work presents the simultaneous transmission of acoustic power and precise acoustic information using a double‐electrode US‐TENG, enabling a battery‐free implant controlled via ultrasound. High and sustained output from a US‐TENG is crucial for operating the versatile system; therefore, a novel triboelectric membrane with a top electrode incorporating a gold‐polymer intermixing layer has been designed. Reversible micro‐cracks form in the intermixing layer, ensuring electrical connectivity under high‐frequency strain. In vivo experiments confirm that the system is biocompatible and can be reliably operated inside living rats. These achievements represent a significant step toward realizing multifunctional implantable electronics that can be reliably powered and controlled by ultrasound.

Exploring alternative manufacturing techniques for high-quality solar cell interconnectors: a comparative study of laser cutting and electric discharge machining

Abstract Solar cell interconnectors are typically crafted from thin foils to establish an electrical connection between two components. For limited production of interconnectors with non-standard dimensions, common production methods (such as stamping and sheet metal processes) cannot be utilized. This article examines alternative techniques, such as Fiber Laser Cutting Machine and Electric Discharge Machining (wire cutting). The laser cutting method did not achieve the desired quality standards, leading to the rejection of the interconnectors. Issues such as burning, local melting, and damage to the silver coating were noted at the edges. The melting of the coating layers formed brittle intermetallic compounds, which can cause cracking and reduce weldability and solderability. In contrast, the Electric Discharge Machining method successfully produces interconnectors with complex shapes by stacking layers of foil. This approach results in high-quality interconnectors that showed no signs of burning or local melting on their edges.

Study of microstructural evolution during operation of electrically connected components and analysis of failure mechanism

Abstract As a key current-carrying structure of high-voltage bushings, the reliability of electrical connection components is crucial to the safe and stable operation of power equipment. To obtain the microstructural evolution of electrical connection components with different deterioration states, CUD strap contactors were deteriorated in different ways, and electron backscatter diffraction technique was used to test the microstructure of strap contactors with different deterioration states. The results showed that compared to the unused contactors, the contact resistance of the contactors under the combined effect of friction and high temperature increased 203.12 times and was in a failed state. During the process from unused state to wear deterioration, high temperature deterioration, and then to eventual failure of the contactors, the average grain size gradually grows from 8.15 μm to 25 μm, the dislocation density gradually decreases from 2.38 × 1014 m−2 to 1.04 × 1014 m−2, and there are a significant proportion of the recrystallized organization. These changes are detrimental to the mechanical properties of the contactors. In addition, the distribution of grain boundaries in the contact area proves the occurrence of over-temperature phenomenon in this area, which will accelerate the deterioration of the contactors and eventually lead to the failure of the component. The relevant conclusions can provide a theoretical basis for the design of electrical connection structure of strap contacts as well as the study of deterioration mechanism.

Wear-free sliding electrical contacts with ultralow electrical resistivity

Sliding electrical contacts are commonly applied in electrical connectors, such as conductive slip rings, pantographs, switches, and commutators. However, they suffer from several unavoidable problems caused by friction and wear, including high energy consumption, intermittent failures, limited life, and even failure disasters. In this study, we realized an ultralow-friction and long-distance wear-free state, defined as structural superlubricity (SSL), between sliding electrical interfaces under ambient conditions. A conductive SSL can be implemented in experiments with single-crystal graphite flakes on flattened metals, such as Au and Ni films. Furthermore, we found that depositing a 2 to 3-nm-thick diamond-like carbon (DLC) film on a nickel alloy can lead to an even lower resistivity than that of metals alone. In addition, we revealed the mechanism by which DLC films can improve the conductivity between graphite and metals through density functional-theory simulations. In addition, we prepared a prototype of the SSL slip ring and proved that it possessed ultralow friction, was wear-free, and had no intermittent failures. Consequently, our results demonstrate a unique type of electrical-contact interface for applications requiring conduction while sliding. Thus, we opened the door for SSL electromechanical coupling.

Investigation of mechanical, electrical conductivity, wear and corrosion performances of traditional CuNi2Si and new high performance CuNiCoSi copper based alloys

ABSTRACT CuNi2Si copper alloy has been utilised in electronics, resistance welding electrodes, and electrical connections. The industry is seeking new copper alloys with improved strength and electrical conductivity. Cu-Ni-Co-Si alloys have been designated as the next generation of high-performance copper alloys. In this study, the cast and hot-forged CuNi2Si and CuNiCoSi alloys were solid-solution treated and aged. Under optimum ageing conditions, alloys were tested for hardness, electrical conductivity, microstructure, mechanical properties, wear resistance, and corrosion resistance. Comparing the CuNiCoSi alloy to the Co-free CuNi2Si alloy, the Co element decreased grain size, accelerating Ni2Si and Co2Si precipitates. The CuNiCoSi alloy has 23% higher conductivity, 31% higher tensile strength, and 17% higher resistance under a 5 N load, 44% higher under a 10 N pressure, and 50% higher under a 20 N load in wear tests than the CuNi2Si alloy. Potentiodynamic studies showed that the CuNi2Si alloy removed 40% more metal per unit time than the CuNiCoSi alloy. The CuNiCoSi alloy outperforms the CuNi2Si alloy in hardness, conductivity, mechanical strength, wear resistance, and corrosion resistance. Due to its outstanding performance, the CuNiCoSi alloy will be vital in industrial equipment, aviation, space, nuclear energy, and electrical power generation.

A batch-fabricated high-density flexible coil enabled by low-temperature bonding technique

In this work, a high-density flexible coil (HFC) is designed and fabricated by stacking and bonding multiple layers of thin flexible coils. A batch fabrication process of the HFC is developed based on a low-temperature gold compression bonding technique. A Cu-Ni-Au electrode-dummy structure is implemented to realize simultaneous electrical connection and mechanical bonding between the flexible coil layers. A proof-of-concept HFC demonstrator is batch-fabricated by bonding process with temperature of 200℃ and pressure of 8 MPa. The fabricated HFC includes 500 turns of coil within a volume of 10 mm×10 mm×0.72 mm, enabling high-coil density with miniaturized footprint. The structural, electrical, and mechanical properties of the HFC are systematically characterized and discussed.

A Review on Friction Stir Welding of Copper: Tool Geometry, Process Parameters, and Joint Properties.

This paper comprehensively reviews friction stir welding (FSW) as applied to copper and its alloys. FSW is a solid-state joining process that offers significant advantages over traditional fusion welding methods, particularly for materials like copper that are difficult to weld conventionally due to their high thermal conductivity and oxidation issues. Over time, the FSW process has been developed for different industries. Copper structures joined through FSW are utilized for nuclear waste storage, electrical connectors, chemical and petrochemical storage, refrigeration systems, heat exchangers, and the aerospace industry. This covers recent advancements in FSW technology, the geometry of the tools used, the process parameters, and the microstructural characteristics and mechanical properties of the joints. It examines the shapes, sizes, and materials of the tools used for welding copper and its alloys, along with process parameters such as rotational speed and traverse speed, and their influence on the quality of the joints. Additionally, the paper presents syntheses of previously published results, highlighting the values of parameters that indicate the quality of the welds, including grain size, microhardness, mechanical strength, and elongation. The challenges and potential solutions in applying FSW to copper are also discussed, providing a starting point for future research and industrial applications.

Enhancing efficiency of dense array CPV receivers with controlled DC-DC converters and adaptive microfluidic cooling under non-uniform solar irradiance

Concentrating solar technologies offer substantial potential for optimizing solar energy for heat and power generation, particularly in green hydrogen production. This study investigates the use of commercial high efficiency concentrated photovoltaic (CPV) cells in a central tower concentrating solar system to enhance energy conversion efficiency. By integrating DC-DC converters with self-adaptive microfluidic cooling systems, we address current mismatches and temperature variations that affect CPV performance. The novel receiver design ensures scalability for large-scale implementations by implementing the electrical connections between DC-DC converters and each CPV cell without creating shaded areas. We numerically model and simulate the thermodynamic and electrical characteristics of a dense array CPV receiver, evaluating six illumination profiles. Our results indicate a significant improvement in receiver efficiency compared to the traditional configuration with bypass diodes, demonstrating an increase from 23.4 % to 30.3 % under a central Gaussian illumination profile, and reaching up to 38 % relative efficiency improvement depending on the applied profile. Power transfer losses decrease from 26 % to 10 % when 200 kW/m2 of illumination non-uniformity occurs. The proposed solution enhances reliability and energy conversion efficiency, presenting a viable path forward for large-scale CPV applications.

Study on Wear Debris Distribution and Performance Degradation of Electrical Connector Under Step Random Vibration Stress

Study on Wear Debris Distribution and Performance Degradation of Electrical Connector Under Step Random Vibration Stress

Facile Formation of Metallic Surface with Microroughness via Spray-Coating of Copper Nanoparticles for Enhanced Liquid Metal Wetting.

This paper presents a simple, fast, and cost-effective method for creating metallic microstructured surfaces by spray-coating a dispersion of copper nanoparticles (CuNPs) onto polymethyl methacrylate (PMMA) substrates, enabling the imbibition-induced wetting of liquid metal. The formation of these microstructured patterns is crucial for the spontaneous wetting of gallium-based liquid metals. Traditional techniques for producing such microstructures often involve complex and costly lithography and vacuum deposition methods. In contrast, this study demonstrates that liquid metal wetting can occur with metal microstructures formed through a straightforward spray-coating process. To immobilize the CuNPs on the polymer substrate, an organic solvent that dissolves the polymer surface was employed as the dispersion medium. The effects of various spray-coating parameters, including distance and time, on the uniformity and immobilization of CuNP films were systematically investigated. Under optimal conditions (120 s of spray time and 10 cm spray distance), CuNPs dispersed in dichloromethane (DCM) yielded uniform and stable microstructured surfaces. The spontaneous wetting of gallium-based liquid metal was observed on the fabricated CuNP film. Additionally, liquid metal selectively wet the CuNP patterns formed by stencil techniques, establishing electrical connections between electrodes. These findings underscore the potential of spray-coating for fabricating metallic surfaces to drive the formation of liquid metal patterns in flexible electronics applications.

Flexible and Extensible Ribbon-Cable Interconnects for Implantable Electrical Neural Interfaces.

The design and characterization of thin-film ribbon cables as electrical interconnects for implanted neural stimulation and recording devices are reported. Our goal is to develop flexible and extensible ribbon cables that integrate with thin-film, cortical penetrating microelectrode arrays (MEAs). Amorphous silicon carbide (a-SiC) and polyimide were employed as the structural elements of the ribbon cables and multilayer titanium/gold thin films as electrical traces. Using photolithography and thin-film processing, ribbon cables with linear and serpentine electrical traces were investigated. A cable design with an open lattice geometry was also investigated as a means of achieving high levels of extensibility while preserving the electrical function of the cables. Multichannel ribbon cables were fabricated with 50 mm lengths and metallization trace widths of 2-12 μm. The ribbon cables tolerate flexural bending to a radius of 50 μm with no change in trace impedance but tolerate less than 5% tensile elongation without trace failure. Ribbon cables with a lattice structure exhibit 300% elongation without failure. The high elongation tolerance is attributed to a lattice design that results in an out-of-plane displacement that avoids fracture or plastic deformation. Extensible ribbon cables underwent up to 50,000 tensile elongation cycles to 45% extension without failure. An electrical interconnect process using through-holes in the distal gold bond pads of the ribbon cables was used to connect to an a-SiC-based MEA. The electrical connection was created by stenciling a conductive epoxy into the through-holes, bridging metallization between the traces, and MEA. The interconnect was tested using a ribbon cable connected to an a-SiC MEA implanted acutely in rat cortex and used to record neuronal activity. These highly flexible and extensible ribbon cables are expected to accommodate large extensions and facilitate cable routing during surgical implantation. They may also reduce tethering forces on implanted electrode arrays, potentially improving chronic neural recording performance.

Wire Bond Ability Enhancement of 8 Leads Small Outline Integrated Circuit and 14 Leads Thin Shrink Small Outline Package Using AuPd Coated Cu Wire Bonding for Automotive Devices

Paper present a study enhancement of wire bonding process in the integrated circuit package with 2N AuPd coated Cu wire (2N-AuPdCu) for Automotive devices. Wire bonding is the electrical connection between pad and leadframe. In present, Au wire is recently use for interconnection while the gold price still exorbitant and caused concern to the wire bonding cost. Cu wire is a lower price and considered to be an alternative for the interconnection but still concern in term of corrosion and reliability. Recently, 4N AuPd coated Cu wire (4N-AuPdCu) material have been introduced for automotive device but still encounter the reliability problem. The 2N AuPd coated Cu wire was developed version for more reliability enhancement and consider to use for alternative wire of automotive device. In the experiment, Au wire, 4NAuPdCu wire and 2N AuPd coated Cu wire were used for wire bonding process on 8 leads Small Outline Integrated Circuit Package (8L-SOIC) and 14 leads Thin Shrink Small Outline Package (14L-TSSOP) to compare wire bond ability. Analysis, this package tested wire bond ability and reliability. The results performed well in wire bond ability and reliability for 2N AuPd coated Cu wire when comparing with Au wire and 4N AuPd coated Cu wire. Therefore, 2N AuPd coated Cu wire can enhance the quality and reliability for 8L-SOIC package and 14L-TSSOP package for automotive device.

Cells of the adult mouse cardiac conduction system in wild type and Nkx2-5 heterozygous loss-of-function mutation

Abstract Background Specialised cardiomyocytes in the cardiac conduction system (CCS) generate and spread the electrical impulse that initiates synchronised heartbeats. Disrupted signal transduction in the atrioventricular (AV) node, a key electrical connection between atria and ventricles, causes AV block. AV block potentially leads to electromechanical uncoupling and sudden cardiac death. Nkx2-5 encodes a cardiac transcription factor that is critical for embryonic CCS formation. Heterozygous loss-of-function mutation of Nkx2-5 (Nkx2-5+/–) results in a hypoplastic CCS in humans and mice and progressive AV block. Purpose We aimed to create a cell atlas of the adult mouse CCS and define the consequences of Nkx2-5 haploinsufficiency on the structural organisation and transcript expression of CCS cells. Methods We performed single-nucleus RNA sequencing on the sinoatrial nodes, AV nodes, His bundles, right bundle branches (RBB) and moderator bands of 17 wild type and 14 Nkx2-5+/– mice (aged 13 to 35 weeks, 5159 CCS cells). Employing single-molecule fluorescent RNA in situ hybridisation (smFISH), we validated selected transcripts and examined the spatial organisation of identified cell populations. Results In the AV node, we identified two subpopulations of pacemaker cells that were spatially separated in the proximal and distal pacemaker region (Fig1). Within these subpopulations, expressed transcripts indicated an atrial-to-ventricular gradient of electrical activity, corresponding to their respective topography. We determined two subpopulations in the His bundle and RBB that were enriched for either slow or fast conduction markers. Spatially, the slow-conducting populations seemed to surround the fast-conducting ones and might act as electrical isolation (Fig1). In Nkx2-5+/- cells of the pacemaker AV node, His bundle, RBB and Purkinje fibres, genes involved in Slit-Robo signalling were dysregulated. Slit-Robo signalling was previously reported in neuronal differentiation and embryonic heart lumen formation. Slit ligand 3 was downregulated in Nkx2-5+/- pacemaker AV node cells (Slit3, log2FC = -2.22, p = 7.0e-42), as was the roundabout guidance receptor 1 (Robo1, log2FC = -0.96, p = 1.6e-4). By contrast, there was upregulation of neural EGF-like 1 (Nell1, log2FC = 3.18, p = 5.3e-6), an alternative ligand of roundabout guidance receptors. Altered Nell1 and Slit3 expressions were confirmed by smFISH (Fig2). Conclusions Our cell atlas defines new CCS cell populations with informative transcriptomic profiles and spatial organisation, providing insights into subpopulations in the AV junction where electrical signals switch from slow to fast conduction. We identified disrupted Slit-Robo signalling in Nkx2-5+/-, possibly impairing differentiation and maturation of the CCS and altering electrophysiologic functions. Our normative anatomical and transcription data on the CCS can inform future studies of cardiac electrophysiology and arrhythmias.Fig1 - Subpopulations in AV junctionFig2 - Nell1 smFISH in pacemaker AV node

Properties of Wedge Wire Bonded Connection Between a Composite Copper Core Aluminum Shell Wire and an 18650 Cylindrical Lithium-Ion Battery Cell.

Wedge wire bonding is a solid-state joining process that uses ultrasonic vibrations in combination with compression of the materials to establish an electrical connection. In the battery industry, this process is used to interconnect cylindrical battery cells due to its ease of implementation, high flexibility and ease of automation. Wire materials typically used in battery pack manufacturing are pure or alloyed aluminum and copper. While copper wires possess better electrical properties, the force used in the bonding process can lead to cell isolator damage and cell thermal runaway. This is an unacceptable result of the bonding process and has led to the development of new types of composite wires containing a copper core embedded in an aluminum shell. This material has the advantage of high copper electrical and thermal conductivity combined with less aggressive bonding parameters of the aluminum wire. The aim of this study was to establish a process window for the wedge wire bonding of 400 µm composite copper-aluminum Heraeus CucorAl Plus wire on the surface of a BAK 18650 battery cell. This study was conducted using a Hesse Bondjet BJ985 CNC wire bonder fitted with an RBK03 bond head designed for the bonding of copper wires. The methods used in this study included light and scanning electron microscopy of bond and battery cell cross-sections, shear testing on the XYZtec Sigma bond tester system, and energy dispersive spectroscopy. The results were compared with a previous study conducted using a wire of the same diameter and made out of high-purity aluminum.