Substrate Resistance Research Articles

Effect of Temperature and Load on Tribological Behavior in Laser-Cladded FeCrSiNiCoC Coatings.

The FeCrSiNiCoC coatings with fine macroscopic morphology and uniform microstructure were made on 1Cr11Ni heat resistant steel substrate by a laser-based cladding technique. The coating consists of dendritic γ-Fe and eutectic Fe-Cr intermetallic with an average microhardness of 467 HV0.5 ± 22.6 HV0.5. At the load of 200 N, the average friction coefficient of the coating dropped as temperature increased, while the wear rate decreased and then increased. The wear mechanism of the coating changed from abrasive wear, adhesive wear and oxidative wear to oxidative wear and three-body wear. Apart from an elevation in wear rate with increasing load, the mean friction coefficient of the coating hardly changed at 500 °C. Due to the coating's transition from adhesive wear and oxidative wear to three-body wear and abrasive wear, the underlying wear mechanism also shifted.

Heteroepitaxial growth of CaGe2 films on high-resistivity Si(111) substrates and its application for germanane synthesizing

Realizing a germanane (GeH) film on insulating substrates is strongly required to understand its intrinsic electric properties in discussing the potential applications for the next-generation field-effect transistor channels. This study investigates the heteroepitaxial growth of CaGe2—the precursor of the GeH—films on a high resistive substrate of FZ-Si(111) using a molecular beam epitaxy with the deposition temperature (Tdepo) as a variable. X-ray diffraction and Raman spectroscopy analyses indicated that a metastable polytype of 2H was dominated in the epitaxial CaGe2 films; the Tdepo must be less than 700 °C to prevent Si diffusion from the substrates. We also synthesize GeH films by immersing some CaGe2 films in HCl acid solutions at a low temperature of −40 °C. Although the obtained grain size of GeH was still as small as several hundred nanometers, we believe that the present study is the first step in obtaining the GeH continuous films directly on insulators necessary for electrical characterizations.

Antenna-on-Chip for Millimeter Wave Applications Using CMOS Process Technology

In this paper, a monopole patch antenna is designed, and the structure of the antenna is analyzed. The manufacturing process adopts TSMC 0.18 μm CMOS process technology. An artificial magnetic conductor (AMC) on the M1 layer is proposed in this paper to increase the radiation gain and reduce the reflection coefficient (S11) magnitude for impedance matching and antenna performance. This method can make up for the radiation efficiency and benefits of the antenna-on-chip that are affected by the high dielectric constant and low resistivity of the silicon substrate of the CMOS process. The antenna designed in this paper obtains a simulated bandwidth of 37.5 GHz to 69.5 GHz using the Electromagnetic Simulation Software, and the fractional bandwidth of the design is 60%. Among them, 62 GHz shows a maximum gain value of −2.64 dBi. Actual measurements have confirmed that the reflection coefficient of the antenna on the chip proposed in this paper is the same as the simulation trend, and a wider bandwidth is obtained from 20.9 GHz to 67 GHz, with a fractional bandwidth of 104.89%. This bandwidth covers millimeter wave 28 GHz, 38 GHz, and 60 GHz application frequencies.

Performance improvements of microchannel heat sink using Koch fractal structure and nanofluids

With the rapid development of microelectronics technology, the heat flux density in the micro-component system is very high. Therefore, the design of new and efficient cooling and heat dissipation devices has become an urgent problem to be solved. We use the Koch fractal structure and nanofluid to create a new type of microchannel heat sink. In this paper, a single-phase method is used to numerically study the flow and heat transfer properties of TiO2-water nanofluids in microchannels and optimize the structure with Koch fractal baffles. The effects of various volume fractions of nanofluids and baffles with varying structures on the inlet and exit pressure drop, flow resistance coefficient, substrate temperature, and Nusselt number (Nu) in the microchannel are investigated. In the Reynolds number (Re) range of 100–1000, the Nu of nanofluid increases with the increase of Re and the Nu increases from 18.19 to 60.41, which increases by 3.32 times, and the flow resistance of nanofluid falls by 1.79 times. Nanofluids' improved heat transfer factors are not all larger than one. The critical point is Re = 439, indicating that the combined heat transfer performance of nanofluids is superior to that of deionized water within the Re range of 100–439.

Characteristics and formation of bedrock mega-grooves (BMGs) in glaciated terrain: 2 – conceptual models of BMG initiation

Understanding BMG formation equates to being able to explain their initiation as well as their subsequent evolution. Several scenarios of bedrock mega-groove (BMG) initiation are proposed here, which attempt to explain how such parallel fluted terrain could be incised through resistant substrates over the relatively short temporal periods associated with uni-directional fast ice flow. In cases where geological controls have been inferred from the BMG morphology or location, groove initiation was likely either structural through the exploitation of linear features, or lithological, whereby the origin of harder erodents necessary for abrading softer rocks can be explained by the succession of adjacent lithologies along former ice flow paths. Where no geological control over BMG initiation could be inferred, it is hypothesized that their initiation was due to antecedent land surface conditions, through gradual bedrock elimination or related to pre-Quaternary regolith on etchplains, which was potentially a source of erodents no longer visible in the landscape.

Plastisphere assemblages differ from the surrounding bacterial communities in transitional coastal environments

Marine plastic contamination is currently considered ubiquitous in aquatic environments. These particles present a resistant and hydrophobic substrate known to promote microbial colonisation and biofilm formation in aquatic ecosystems, the so-called “Plastisphere”, raising concerns about its potential ecological risks. The novelty of this topic translates into a relatively low number of studies, including for transitional coastal ecosystems, such as sandy beaches or estuarine habitats. Therefore, a sampling campaign was conducted in two transitional coastal ecosystems - the Mondego estuary (Portugal) - and adjacent sandy beaches (winter 2020). After visual sorting and filtering of suspected particles under sterile conditions DNA extraction and 16S rRNA amplicon high throughput sequencing was used to profile the bacterial communities on the surface of plastic particles and from those found on the water and sediments from the sampled transitional coastal ecosystems. All particles were characterised according to type, colour and size, and the chemical nature of the particles was determined by FTIR-ATR or μ-FTIR spectroscopy after DNA extraction.All samples contained plastics in several sizes (micro and mesoplastics), shapes (higher abundances of fragments on beaches and fibres in the estuarine waters), colours and polymers. Although no significant differences were detected in the α-diversity indexes of the bacterial communities between plastics and their surrounding environments, data showed the occurrence of unique key bacterial groups on plastics from both environments, such as pathogens (e.g., Lactococcus, Staphylococcus and Streptococcus) and groups commonly associated with wastewater treatment plants (e.g., members of the phylum Firmicutes). This highlights the concerns for plastics to act as vectors of transmission and spread of these bacterial groups in transitional coastal ecosystems. Furthermore, it raises the possibility that (micro)plastics entering the estuary from the sea play a substantial contribution to overall dynamics of (micro)plastics and their microbial assemblages in the estuarine system.

A Low‐Power WLAN CMOS LNA for Wireless Sensor Network Wake‐Up Receiver Applications

Wireless communication integration is related to many challenges such as reliability, quality of service, communication range, and energy consumption. As the overall performance of wireless sensor networks (WSN) will be improved if the capacity of each sensor node is optimized, several techniques are used to fine‐tune the various circuits of each node. In recent works, the wake‐up receiver nodes have been introduced to minimize latencies without increasing energy consumption. To overcome the sensitivity of wake‐up receiver limitations, a design of a low‐noise amplifier (LNA) with several design specifications is required. This article discusses the relevance of the wake‐up receiver in WSN applications and provides a brief study of this component. An LNA design for WSN wake‐up receiver applications is presented. The challenging task of the LNA design is to provide equitable trade‐off performances such as noise figure, gain, power consumption, impedance matching, and linearity. The LNA circuit is designed for wireless personal area network (WLAN) standards utilizing RF‐TSMC CMOS 0.18 μm. Two innovative techniques are applied to the LNA topology to improve its performance: forward body biasing is used to reduce power consumption by 11.43 mW, and substrate resistance is added to reduce noise by 1.8 dB. The developed LNA achieves a noise figure of 1.6 dB and a power gain of 21.7 dB at 5.2 GHz. At 0.6 V, the designed LNA dissipates 0.87 mW.

Abstract 2675: The Dnase1L3 flexible C-terminal domain and altered charges in the actin recognition site result in broad substrate diversity and resistance to actin inhibition

Abstract 2675: The Dnase1L3 flexible C-terminal domain and altered charges in the actin recognition site result in broad substrate diversity and resistance to actin inhibition

Insulin receptor substrate-1 gene polymorphism and lipid panel data in type 2 diabetic patients with comorbid obesity and/or essential hypertension.

Objective. The hallmarks of type 2 diabetes mellitus (T2DM) are insulin resistance (IR) and insulin receptor substrate (IRS) proteins essential for the insulin signaling. IRS-1 gene has not only been shown to be associated with T2DM, but also has indicated that it may significantly correlate with diabetic complications, such as coronary heart disease and obesity. The aim of this study was to evaluate changes of the lipid panel data in T2DM patients with comorbid obesity and/or essential hypertension in connection with the IRS-1 (rs2943640) polymorphism. Methods. The study involved 33 T2DM patients and 10 healthy individuals. The IRS-1 (rs2943640) polymorphism was genotyped using a TaqMan real-time polymerase chain reaction method. Blood serum lipid panel data were determined with commercially available kits using a Cobas 6000 analyzer. Results. Analysis of the serum lipid panel data depending on the presence of the C/A alleles of IRS-1 (rs2943640) polymorphism in T2DM patients, regardless of the presence/absence of comorbidities, showed significantly lower level of high-density lipoprotein cholesterol (HDL-C) and significantly higher level of non-HDL-C in the carriers of C allele vs. carriers of A allele. In T2DM patients with comorbid obesity and essential hypertension, proatherogenic lipid changes were found in both C and A alleles carriers. Analysis of the effect of IRS-1 (rs2943640) genotypes on serum lipid panel data in T2DM patients, regardless of the presence/absence of comorbidities, showed that the CC genotype carriers had more pronounced pro-atherogenic changes vs. carriers of СА and АА genotypes. In the comorbid course of T2DM (both in combination with obesity and obesity and essential hypertension), pro-atherogenic changes were found in the carriers of the CA genotype of IRS-1 (rs2943640) polymorphism. Conclusions. The presence of the C allele of IRS-1 (rs2943640) polymorphism in both homo-zygous and heterozygous states indicates increased risk of pro-atherogenic changes in T2DM patients with comorbid obesity and/or essential hypertension.

Current-voltage simulation analysis of MIS structure utilizing aluminium nitride on high resistivity silicon

High resistivity silicon is increasingly becoming one of the subjects of interest in optimizing the performance of MIS photodetectors as it offers better bias responses compared to low resistivity silicon. The incorporation of thin AlN as the tunnelling insulator in MIS structure utilizing high resistivity silicon has shown promising photocurrent to dark current ratios, suggesting potential integration of the structure. In this work, the MIS structure on high resistivity silicon with AlN tunnelling insulator is simulated and empirically modelled using previous experimental work. The effects of substrate resistivity and AlN thickness are then evaluated. Simulation work shows good agreement with the previous experimental work, except for the photocurrent characteristics in the inversion region, where the recorded values are 107 magnitude lower than the reported experimental values. The photocurrent characteristics for MIS structures on high resistivity silicon is recorded to be higher than the structures on low resistivity silicon. Meanwhile, both dark current and photocurrent increases with decreasing AlN thickness up until 1 nm. Lastly, no conclusive evidence from this simulation work to show any tunnelling behaviour in the inversion region for all cases.

Edge-TCT evaluation of high voltage-CMOS test structures with unprecedented breakdown voltage for high radiation tolerance

This paper presents the edge Transient Current Technique (eTCT) measurements of passive test-structures on the UKRI-MPW0 pixel chip, a 280 µm thick proof-of-concept High Voltage-CMOS (HV-CMOS) device designed and fabricated in the LFoundry 150 nm technology node with a nominal substrate resistivity of 1.9 kΩ cm. Samples were irradiated up to 1 × 1016 1 MeV neq cm−2 with neutrons to observe the change in depletion depth and effective doping concentration with irradiation. A depletion depth of the sensor was found to be ≈50 µm at ≈−400 V at 1 × 1016 1 MeV neq cm−2. A stable damage introduction rate (g c ) was also calculated to be 0.011 ± 0.002 cm−1.

Mg-implanted vertical GaN junction barrier Schottky rectifiers with low on resistance, low turn-on voltage, and nearly ideal nondestructive breakdown voltage

Vertical GaN junction barrier Schottky (JBS) diodes with superior electrical characteristics and nondestructive breakdown were realized using selective-area p-type doping via Mg ion implantation and subsequent ultra-high-pressure annealing. Mg-ion implantation was performed into a 10 μm thick Si-doped GaN drift layer grown on a free-standing n-type GaN substrate. We fabricated the JBS diodes with different n-type GaN channel widths Ln = 1 and 1.5 μm. The JBS diodes, depending on Ln, exhibited on-resistance (RON) between 0.57 and 0.67 mΩ cm2, which is a record low value for vertical GaN Schottky barrier diodes (SBDs) and high breakdown (BV) between 660 and 675 V (84.4% of the ideal parallel plane BV). The obtained low RON of JBS diodes can be well explained in terms of the RON model, which includes n-type GaN channel resistance, spreading current effect, and substrate resistance. The reverse leakage current in JBS diodes was relatively low 103–104 times lower than in GaN SBDs. In addition, the JBS diode with lower Ln exhibited the leakage current significantly smaller (up to reverse bias 300 V) than in the JBS diode with large Ln, which was explained in terms of the reduced electric field near the Schottky interface. Furthermore, the JBS diodes showed a very high current density of 5.5 kA/cm2, a low turn-on voltage of 0.74 V, and no destruction against the rapid increase in the reverse current approximately by two orders of magnitude. This work demonstrated that GaN JBS diodes can be strong candidates for low loss power switching applications.

Performance Studies of the ATLASpix HV-MAPS Prototype for Different Substrate Resistivities

The ATLASpix high-voltage monolithic active pixel sensor (HV-MAPS) was designed as a technology demonstrator for the ATLAS ITk Upgrade and the CLIC tracking detector. In this contribution new results from laboratory-based energy calibration measurements using fluorescence X-rays are presented for the ATLASpix_Simple matrix. These findings are complemented by new results from test-beam studies with inclined tracks, in which the active charge collection depth is determined.

Development and characterization of high voltage CMOS particle pixel sensor with integrating electronics

We present a High Voltage (HV) CMOS particle pixel sensor with pixel electronics based on a high dynamic range integrator. The application is beam monitoring at an ion beam therapy facility. The test sensor chip has been implemented in an180 nm HV-CMOS technology with a high resistivity substrate. Readout electronics are implemented on-chip and sensing elements formed by n in p substrate. Beam test and lab measurements are presented.

Resisting Dendrites in Lithium Batteries, One Pinhole at a Time

For humanity to successfully transition from fossil fuels, the mismatch in the demand and supply of renewable energy must be addressed by reliable, high energy storage systems. One promising energy storage system is the lithium metal battery (LMB), owing to the high gravimetric capacity of lithium (3860 mAh/g). The potential gain in volumetric and gravimetric energy density offered by LMBs could usurp today’s lithium-ion battery technology and revolutionize energy storage. However, the lifetime of LMBs is hindered by morphological instabilities experienced during the electrodeposition of lithium.Modifications of the solid electrolyte interphase (SEI) and electrolyte are the most common strategies for improving lithium metal morphology. However, electrolyte and SEI engineering are often tedious, based on trial and error, and insufficient for enhancing lithium electrodeposition. Here, we demonstrate a new, alternative strategy for controlling lithium metal morphology and improving electrochemical performance that is independent of the electrolyte and SEI. By modifying the current collector with atomic layer deposited (ALD) thin films of ZnO, SnO2, and Al2O3, we show that lithium deposits atop, rather than beneath, the thin films, resulting in changes in lithium morphology and battery performance that are strongly dependent on the electrical resistance of the ALD films. The results show that low resistance copper modification films like SnO2 and ZnO provide numerous sites for lithium nucleation and promote the formation of high surface area (fast electrolyte consuming) lithium deposits, while the highly resistive Al2O3-modified copper reduces the available sites for lithium nucleation and promotes the formation of low surface area (slow electrolyte consuming) clusters of lithium deposits.We propose and demonstrate the first recorded mechanism for the connection between electrical resistance and lithium growth - we propose that, in resistive substrates, lithium metal nucleates atop only pinhole sites, then grows laterally by the radial diffusion of lithium ions from the electrolyte. We prove this mechanism analytically, using diffusion controlled current equations, and experimentally by introducing patterned pinholes into a resistive, pinhole-free substrate. We generalize the concept of resistance-controlled morphology and demonstrate high battery performance in three distinct classes of electrolytes, culminating in anode-free pouch cells that retain 60% of their initial discharge capacity after 100 cycles. This work presents a new approach for understanding the electrodeposition of lithium and tuning the performance of lithium metal batteries.

Determining Substrate Oxygen Transport Resistance at Limiting Current Using Pore Network Modelling

The polymer electrolyte membrane (PEM) fuel is a promising technology to supplant traditional, greenhouse gas emitting energy conversion devices. However, widespread commercial adoption of the PEM fuel cell is hindered by the high cost of the precious metals required for its catalyst (1). The amount of catalyst required in a PEM fuel cell can be reduced if the reactant (oxygen) is delivered more efficiently to the catalyst. Therefore, previous studies have sought to characterize the mechanisms affecting oxygen transport in PEM fuel cells (2)(3)(4)(5). In past studies, the oxygen transport resistance of a PEM fuel cell was measured at limiting current, and this value was further decomposed into contributions from individual PEM fuel components using empirical modelling. By resolving each PEM fuel cell component’s contribution to oxygen transport resistance, an informed approach can be undertaken to design next generation components with enhanced oxygen transport capabilities.In this study, we employed pore network modelling to quantify the oxygen transport resistance arising from the presence of liquid water within the substrate region of the gas diffusion layer (GDL). First, we captured the operando liquid water distribution within a PEM fuel cell operating at limiting current using synchrotron X-ray radiography. Next, we used a combination of invasion percolation and an in-house water invasion inlet selection algorithm to partially saturate the representative pore network of the substrate and to reproduce the mean water saturation. Finally, we obtained substrate oxygen transport resistance values by performing transport simulations on the partially saturated pore network and compare our findings with the experimental observations. References X. X. Wang, M. T. Swihart, and G. Wu, Nature catalysis, 2, 7 (2019).D. R. Baker, D. A. Caulk, K. C. Neyerlin, and M. W. Murphy, J. Electrochem. Soc., 156, B991 (2009).T. Reshtenko, J. St-Pierre, J. Electrochem. Soc., 161, F1089 (2014)D. Muirhead, R. Banerjee, M. G. George, N. Ge, P. Shrestha, H. Liu, J. Lee, A. Bazylak, Electrochimica Acta, 274 (2018).N. Ge, P. Shrestha, M. Balakrishnan, D. Ouellette, A. K. C. Wong, H. Liu, C. H. Lee, J. K. Lee, A. Bazylak, Electrochimica acta, 328 (2019).

Comparative study on metal versus zirconium dioxide infrastructure manufacturing in prosthetic rehabilitation in the maxillary frontal zone

Prosthetic rehabilitation of the maxillary front teeth is an extremely laborious problem for the dental team, consisting of the dentist and the dental technician. If for the physiognomic component the most recommended materials are the ceramic masses, for the resistance substrate there are several variants. Conventional technologies using dental alloys and modern ones involving the use of zirconium dioxide can be used successfully in performing fixed prosthetic restorations in the maxillary frontal area, both options having both advantages and disadvantages, as we will describe in this material.

Phonons in complex twisted crystals: Angular momenta, interactions, and topology

Phonons and their interactions are critically important for a variety of energy-relevant applications ranging from low thermal resistance substrates to thermal barrier coatings. Fundamental insights into the nature of phonons and allowed interactions are governed by the underlying symmetries of the crystal lattice. In this paper, we provide a comprehensive and detailed description of lattice dynamics derived from twist symmetries of chiral and achiral crystals---twist dynamics. Phonon bands naturally carry quantized crystal angular momentum derived from rotational phases, which give insights into the nature of band crossings and avoided crossings, selection rules for phonon interactions, and topological band crossing behaviors. Twist dynamics is demonstrated for a variety of materials covering a range of space groups, symmetry operations, twist axis orientations, and constituent elements. Furthermore, twist symmetry offers insights into peculiar features observed in scattering measurements. In this context, we present inelastic neutron scattering measurements for rutile ${\mathrm{TiO}}_{2}$ and explain them using twist dynamics.

Effects of process parameters and carbon nanotubes content on microstructure and properties of laser cladding composite coatings using Ni-Ti-Cr-carbon nanotubes

The Ni-Ti-Cr-carbon nanotubes (CNTs) composite coatings was successfully fabricated by laser cladding. The optical microscope was used to observe the metallographic structure of the composite coating, the phase composition of the composite layer was detected by XRD, the microstructures of the composite coatings were observed by SEM, and the point distribution and line distribution of elements were analyzed by EDS. With the increase of laser specific energy (Es) and CNTs content, the TiC enhanced particles in the composite coatings evolves into coarse dendrites. Compared with the mild steel substrate, the microhardness and wear resistance of the composite coatings are obviously improved. The maximum microhardness obtained by the composite coating is approximately 5 times that of the mild steel substrate. The increase of Es and the excessive content of CNTs will reduce the microhardness and wear resistance of the composite coatings. The in situ synthesis of TiC particles not only enhance the microhardness of the composite coatings, but also improve the wear resistance of the coatings.

Effect of Scanning Speed on Properties of Laser Surface Remelted 304 Stainless Steel

In order to study the microstructure and properties of stainless steel after laser surface remelting, based on the theory of laser surface remelting, a simulation model of nanosecond-pulsed laser surface remelted stainless steel was established to study the evolution law of the Marangoni force of the molten pool during laser surface remelting. A single-lane laser remelting experiment was performed to study the variation of the scanning speed on the remelting width, roughness, and layer microtopography. The “S” scanning path was used to remelt the stainless steel surface to investigate the bonding force between the remelted layer and the substrate, the hardness, microscopic morphology, and corrosion resistance. The results show that the viscosity of the liquid metal in the molten pool increases with the increase of the scanning speed. Larger liquid viscosity and smaller surface tension temperature gradients promote a weaker flow of liquid metal, which reduces the velocity of the liquid metal flow in the molten pool. With the increase of scanning speed, the remelting width gradually decreases, but the roughness gradually increases. When the element content of Cr increases, the element content of Fe and O decreases. The surface is covered with an oxide film, the main components of which are oxides of Cr and Fe, the remelted layer is greater than that of the substrate, and the corrosion resistance is improved. Laser surface remelting technology can improve the structure and properties of 304 stainless steel.