Critical Charge Research Articles

High‐Energy‐Density Waterborne Dielectrics from Polyelectrolyte‐Colloid Complexes

AbstractTo meet the demands of miniaturization and integration of next‐generation power systems, a major challenge is to improve the energy density of used dielectric capacitors. Polymer nanocomposites are of great potential for high‐energy‐density capacitors. However, most of them are prepared via melt blending at high temperatures or solution processing in hazardous organic solvents, which are energy consuming and environmentally problematic. It has long remained economically and ecologically challenging to develop new dielectric materials. Here, a class of high‐energy‐density dielectrics made by electrostatically complexing polyvinylidene fluoride (PVDF) latex with oppositely charged chitosan in an aqueous phase is reported. At the charge neutralization point, the film of PVDF@Chitosan complexes demonstrates the highest breakdown strength (630 MV m−1) and recoverable energy density (10.1 J cm−3), which are respectively 279% and 421% higher than the bare PVDF latex film, and far beyond most of the conventional solvent‐ or melt‐processed polymer films. The largely improved capacitive performances are ascribed to the significant minimization of losses at the critical charge neutralization point. The concept can be extended to a wide range of colloids, including polystyrene latex and aqueous bentonite suspension, highlighting the versatility of the proposed approach to develop environmentally friendly high‐performance capacitors.

Observation of a critical charge mode in a strange metal.

Understanding the strange metallic behavior that develops at the brink of localization in quantum materials requires probing the underlying electronic charge dynamics. Using synchrotron radiation-based Mössbauer spectroscopy, we studied the charge fluctuations of the strange metal phase of β-YbAlB4 as a function of temperature and pressure. We found that the usual single absorption peak in the Fermi-liquid regime splits into two peaks upon entering the critical regime. We interpret this spectrum as a single nuclear transition, modulated by nearby electronic valence fluctuations whose long time scales are further enhanced by the formation of charged polarons. These critical charge fluctuations may prove to be a distinct signature of strange metals.

Patient-oriented research and the shiny object syndrome.

Patient-oriented research and the shiny object syndrome.

Sanitation citizenship: state expectations and community practices of shared toilet use and maintenance in urban India

Although India declared itself “open defecation free” in 2019, critics charge that its national urban sanitation campaign, Swachh Bharat Mission–Urban (SBM-U), has failed. SBM-U provided community toilets in informal settlements where household latrines were unviable, delegating their upkeep to local governments and users. Initially, these community toilets were used. However, the failure to maintain and repair them resulted in a reversion to open defecation, forcing the state to reconsider its decision to withdraw after construction. We use the SBM-U to develop a framework of “sanitation citizenship”, which emerges through sanitation infrastructure’s use and disuse, and emerges over its life course. We trace how mutual expectations and everyday practices of citizenship by the state and users aligned and fractured during the construction, maintenance and repair phases of community toilets. We argue that the changing material condition of infrastructure is critical to negotiations over mutual obligations and definitions of the citizenship contract.

Phase Transformation during the Selective Dissolution of a Cu85Pd15 Alloy: Nucleation Kinetics and Contribution to Electrocatalytic Activity

This study determined the critical parameters for the morphological development of the electrode surface (the critical potential and the critical charge) during anodic selective dissolution of a Cu-Pd alloy with a volume concentration of 15 at.% palladium. When the critical values were exceeded, a phase transition occurred with the formation of palladium's own phase. Chronoamperometry aided in the determination of the partial rates of copper ionization and phase transformation of palladium under overcritical selective dissolution conditions. The study determined that the formation of a new palladium phase is controlled by a surface diffusion of the ad-atom to the growing three-dimensional nucleus under instantaneous activation of the nucleation centres. We also identified the role of this process in the formation of the electrocatalytic activity of the anodically modified alloy during electro-oxidation of formic acid. This study demonstrated that HCOOH is only oxidated at a relatively high rate on the surface of the Cu85Pd15 alloy, which is subjected to selective dissolution under overcritical conditions. This can be explained by the fact that during selective dissolution of the alloy, a pure palladium phase is formed on its highly developed surface which has prominent catalytic activity towards the electro-oxidation of formic acid. The rate of electro-oxidation of HCOOH on the surface of the anodically modified alloy increased with the growth of the potential and the charge of selective dissolution, which can be used to obtain an electrode palladium electrocatalyst with a set level of electrocatalytic activity towards the anodic oxidation of formic acid.

Curvature induced scalarization of Kerr-Newman black hole spacetimes

With certain nonminimal coupling between a massless scalar field and the Gauss-Bonnet curvature invariant in the extended scalar-tensor-Gauss-Bonnet (ESTGB) field theory, tachyonic instability of the Kerr-Newman (KN) black hole is promoted. Critical spin and charge for the onset of the spontaneous scalarization phenomenon for the KN black hole are calculated in the infinitely large coupling limit. Then the analytical formula for the coupling-strength-dependent critical existence line is obtained for the black-hole-scalar-field configuration in a finite large coupling regime. Moreover, numerical methods are used to perform threshold curves that are boundaries between bald KN black holes and their hairy counterparts. Intriguingly, we get to know the KN black hole can be scalarized in the vanishing spin limit in ESTGB theory.

Radiation hard true single-phase-clock logic for high-speed circuits in 28 nm CMOS

True Single-Phase-Clock (TSPC) dynamic logic is widely used in high-speed circuits such as high-speed SERDES (Serializer/Deserializer) and frequency dividers. TSPC flip-flops (FF) are known for their high operational speed and low power consumption, compared to static FFs. Due to the relatively high leakage currents in modern CMOS processes, the use of leakage protection techniques of the storage nodes in TSPC must be considered, especially at high radiation doses. In this paper, the limitations originating from Total Ionization Dose (TID)-induced subthreshold leakage currents are analysed and radiation-hardening-by-design (RHBD) circuit techniques are proposed. Additionally, Single Event Upsets (SEU) are investigated by quantifying the critical charge of the leakage protected TSPC FF. The results are compared to both the static and the TSPC FF without leakage mitigation.

Phases of mathcal{N} = 2 Sachdev-Ye-Kitaev models

We study mathcal{N} = 2 supersymmetric Sachdev-Ye-Kitaev (SYK) models with com- plex fermions at non-zero background charge. Motivated by multi-charge supersymmetric black holes, we propose a new mathcal{N} = 2 SYK model with multiple U(1) symmetries, integer charges, and a non-vanishing supersymmetric index, realizing features not present in known SYK models. In both models, a conformal solution with a super-Schwarzian mode emerges at low temperatures, signalling the appearance of nearly AdS2/BPS physics. However, in contrast to complex SYK, the fermion scaling dimension depends on the background charge in the conformal limit. For a critical charge, we find a high to low entropy phase transition in which the conformal solution ceases to be valid. This transition has a simple interpretation– the fermion scaling dimension violates the unitarity bound. We offer some comments on a holographic interpretation for supersymmetric black holes.

Design of radiation-hardened memory cell by polar design for space applications

This paper proposed a radiation-hardened memory cell (RHMC12T) by polar design for space applications. The proposed cell has the following advantages: (1) it can tolerate all single-node upset and partial double-node upset based on combining radiation hardened by polar design technology together with reasonable layout topology; (2) comparing with the state-of-the-art radiation hardened SRAM cells, simulation results show the proposed RHMC12T cell has lower write access time, higher wordline write trip voltage, larger static noise margin, and larger critical charge. And Monte Carlo simulation results have shown that RHMC12T has good robustness; (3) electrical quality metric is widely used to evaluate the overall performance of SRAM cells. And RHMC12T has the largest EQM compared with the state-of-the-art radiation hardened SRAM cells, which suggests the proposed RHMC12T exhibits good circuit performance (including write/read access time, static noise margin et al.) as well as good radiation resistance performance with sacrificing a large area overhead.

Plasma screening effect on electron-electron interactions

In the calculation of atomic structures within the plasma environment, the plasma screening effect on nuclei - electron interactions is generally considered, but the plasma screening effect on electron - electron interactions is less considered. In this work, the MCDHF method combined with the screening potential is used to study plasma screening effect on the atomic structure parameters versus the electron density, electron temperature, nuclear charge and the number of bound electrons. For the ground states and the first excited states of helium-like ions, the energy shifts, transition energy shifts and transition probability shifts caused by the plasma screening effect on electron-electron interactions increase with the increase of electron densities and decrease with increasing the electron temperatures, respectively. With the increase of nuclear charge, the energy shifts increase gradually and tends to a stable value, while the transition energy shifts and transition probability shifts decrease gradually and tend to 0. The energy shifts increase with the increase of the number of bound electrons. The electron density, electron temperature, nuclear charge and number of bound electrons corresponding to the percentages of transition energy shifts and transition probability shifts caused by plasma screening on electron-electron interactions greater than or equal to 10%, are called as the critical electron density, critical electron temperature, critical nuclear charge and critical number of bound electrons, respectively. When one of the following four conditions is satisfied, the percentages of transition energy shifts and transition probability shifts caused by plasma screening on electron-electron interactions will be greater than or equal to 10%, and the plasma screening effect on electron - electron interactions can not be ignored. 1) The electron density is greater than or equal to the critical electron density, when the electron temperature is a fixed value. 2) The electron temperature is less than or equal to the critical electron temperature, when the electron density is a fixed value. 3) The nuclear charge is less than or equal to the critical nuclear charge, when the electron density and temperature are both fixed. 4) The number of bound electrons is greater than or equal to the critical number of bound electrons, when the electron density and temperature are both fixed.

Experimental study on real-time measurement of single-event effects of 14 nm FinFET and 28 nm planar CMOS SRAMs based on Qinghai-Tibet Plateau

Based on the Yangbajing International Cosmic Ray Observatory in Lhasa with an altitude of 4300 m, a long-term real-time experiment is carried out in order to measure the atmospheric radiation induced soft errors in 14 nm FinFET and 28 nm planar CMOS SRAM array. The underlying mechanisms are also revealed. Five boards are used in the test, four of which are equipped with 28-nm process devices, and one board is equipped with 14-nm process devices. After removing the unstable bad bits, the actual effective test capacity is 7.1 Gb. During the test, the on-board FPGA reads the stored contents of all the tested devices in real time, reports the error information (occurrence time, board number, column number, device number, error address, error data) and corrects the error. The duration of the test is 6651 h. A total of 56 single event upset (SEU) events are observed, they being 24 single bit upset (SBU) events and 32 Multiple Cell Upset (MCU) events. Based on previous results of 65-nm SRAM, the study finds that SER continues to decrease with the reduction of process size, but the proportion of MCU in 28-nm process devices (57%) exceeds SBU, which is a process “maximum point” of MCU sensitivity, and the maximum size of MCU is 16 bits. Although the Fin spacing of the 14-nm FinFET device is only about 35 nm, and the critical charge decreases to sub-fC, the introduction of the FinFET structure leads to the change of charge collection and the sensitive volume sharing mechanism , and the shallow trench isolation leads to the narrowing of the charge diffusion channel. On the other hand, the surface area of the sensitive volume decreases to 0.0024 μm<sup>2</sup>, resulting in a significant decrease in the soft error rate of both SBU and MCU in the 14-nm process.

What, Exactly, Is Wrong with Confucian Filial Morality?

Confucianism’s emphasis on filial piety is both a hallmark of its approach to ethics and a source of concern. Critics charge that filial piety’s extreme partialism corrupts Chinese society and should therefore be expunged from the tradition. Are the critics correct? In this article, we outline the criticism and note its persistence over the last century. We then evaluate data from the empirical study of corruption to see whether they support the claim that partialism corrupts. Finally, we report some recent experimental work done with colleagues testing the claim that filial piety is associated with tolerance of corruption in Chinese societies. The results suggest that the critics are on to something. However, partialism (or kin affection) is not a cause of concern. Instead, authoritarianism (another aspect of filial piety) is associated with tolerance of corruption. We conclude that critics should reformulate their criticisms if they seek to combat corruption effectively.

Proven Impact of an Advanced Air Purification System in the Reduction of Infectious Airborne and Surface Pathogens, Concomitant Reduction of Hospital-acquired Infections and Length of Stay, and Improvement in Health-care Economics.

Proven Impact of an Advanced Air Purification System in the Reduction of Infectious Airborne and Surface Pathogens, Concomitant Reduction of Hospital-acquired Infections and Length of Stay, and Improvement in Health-care Economics.

Improving the quality indicators and performance of logical blocks and static memory of the microprocessor as part of improving the energy efficiency of devices

The study is aimed at consideration of improving the energy efficiency of devices. The article discusses methods for ensuring resistance to heavy charged particles (HCP) of a microprocessor RAM unit . A description of the implementation and a block diagram of static memory based on dummy blocks is provided. The work discusses methods of combating the biopolar effect, which are aimed at controlling the potential of the transistor body and reducing resistance. The dependence of the critical charge of a SOI memory cell on the gain of a parasitic biopolar transistor is modeled. To increase the fault tolerance of combinational circuits consisting of control logic and decoder blocks, redundancy is used at the level of individual gates. The article is considered to be useful for IT engineers and energy engineers, as well.

Description of Photodegradation Mechanisms and Structural Characteristics in Carbon@Titania Yolk–Shell Nanostructures by XAS (Small 2/2023)

Carbon@Titania Yolk–Shell Nanostructures In article number 2203881, Shih-Yun Chen, Chi-Liang Chen, and co-workers use carbon@titania yolk-shell nanostructures for acetaminophen photocatalytic degradation in water. X-ray absorption spectroscopy discovers critical charge transfer processes and holes that formed in the p-d hybridized bands significantly enhance photodegradation ability under solar irradiation.

Effect of substrate charge density on the adsorption of intrinsically disordered protein amyloid β40: a molecular dynamics study.

The inhibitory effect of negatively charged gold nanoparticles (AuNPs) on amyloidogenic protein fibrillation has been established from experiments and computer simulations. Here, we investigate the effect of the charge density (σ) of gold (Au) surfaces on the adsorption of the intrinsically disordered amyloid β40 (Aβ40) monomer using molecular dynamics (MD) simulations. On the basis of the binding free energy, some key residues (ARG5, LYS16, LYS28, LEU17-ALA21, ILE31-VAL38) were found to be responsible for preventing the β-sheet formation, which is known to be a precursor for fibrillation. Until a critical charge density (σc) of -0.167 e nm-2, the key residues remained adsorbed on the Au slab. A saturation in the number of condensed counterions (Na+) on Aβ40 was also observed at σc. Beyond σc, the condensation of Na+ occurs only on the Au slab, leading to competition between positively charged key residues and condensed ions. This competition was found to be responsible for the lack of adsorption of the key residues, leading to β-sheet formation for σ > -0.167 e nm-2. This study suggests that if the key residues are not adsorbed, then β-sheet formation is observed, which can then lead to the development of proto-fibrils and subsequently fibrillation. Therefore the surface should have an optimal charge density to be an effective inhibitor of fibrillation.

Energy-Efficient Dual-Node-Upset-Recoverable 12T SRAM for Low-Power Aerospace Applications

With technology scaling, transistor sizing as well as the distance between them, is decreasing rapidly, thereby reducing the critical charge of sensitive nodes. This reduction makes SRAM cells used for aerospace applications more susceptible to radiation as it can cause single-event upsets (SEUs) and also single-event multi-node upsets (SEMNUs). This article presents an energy-efficient dual-node-upset-recoverable 12T SRAM cell for low-power aerospace applications, EDP12T, in 65-nm CMOS technology. The proposed cell mitigates SEUs as well as SEMNUs. To judge the relative performance of EDP12T, a comparative study is made between it and other radiation-hardened cells: RHM12T, QUCCE12T, QUATRO12T, RHD12T, SRRD12T, RHPD12T, RSP14T, LWS14T, SAR14T, and S8P4N16T. EDP12T can recover from SEUs induced at all the sensitive nodes and from SEMNUs that have occurred at its internal node-pair. EDP12T exhibits better write performance than most of the comparison cells, it also consumes the least energy during write mode, and lower energy than most of the comparison cells during read mode. EDP12T exhibits a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.08\times /1.17\times /1.37\times /1.56\times /2.32\times $ </tex-math></inline-formula> higher read stability than S8P4N16T/RHPD12T/QUCCE12T/QUATRO12T/LWS14T. Additionally, EDP12T dissipates the lowest hold power among all the cells for comparison, except for RHM12T. These improvements are obtained by the proposed cell while consuming a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.03\times /1.06\times /1.07\times /1.08\times /1.14\times /1.43\times /2.01\times $ </tex-math></inline-formula> lower area than SAR14T/RHD12T/S8P4N16T/RSP14T/LWS14T/RHPD12T/SRRD12T. However, these advantages come with a slight penalty in the read delay.

Consequences of approximating electron correlation effects

ABSTRACT The effect of approximating electron correlation in few-electron systems is investigated using three wavefunctions: the many body wavefunction referred to as fully-correlated (FC), the Hartree Fock wavefunction (HF), and the Colle and Salvetti Jastrow-style wavefunction (CS) used in the derivation of the popular Lee, Yang and Parr (LYP) correlation functional. The electron correlation energy, static and dynamic Coulomb holes, various expectation values, and radial energy distributions (energy densities) are considered. It is shown that whilst the CS wavefunction can capture the behaviour of the wavefunction at the singularities of the Coulomb potential corresponding to the coalescence of two particles and decreases the area of the primary static Coulomb hole by nearly 30% compared to HF for He and Li + , it is unable to accurately model expectation values that depend on the whole of space and key features of the electron density behaviour in dynamic Coulomb holes and the energy density behaviour in energy distributions. These issues are amplified when considering the hydride ion and a system with the critical nuclear charge for binding.

Discharge characteristics of leader inception and development under 10 m long air gap—experimental observation and simulation results

AbstractThe physical mechanism of leader formation and development is not well understood. In this study, we present experimental and simulation results obtained with a 10 m long air gap discharge. A 10 m outdoor discharge experiment is carried out to obtain the current, voltage, and optical image during the leader discharge process. Four different impulse voltages were applied to the rod‐plane gap. The measured current is used as an input for a plasma model, then the temperature and electric field could be calculated. The simulation results show that the temperature of the streamer stem during the dark period may exceed 2000 K. In addition, the critical charge required for leader initiation can be as low as 0.27 μC for a 10 m air gap. The channel temperature is relatively stable in the process of leader development, which is maintained at about 4500 K. The electron density is about 0.5–3 × 1020 m−3, and the discharge channel conductivity fluctuates in the range of 1–10 S/m for the leader current between 1 and 2 A. A long dark period is tended to be associated with a higher injected charge by the first streamer. It is inferred that the voltage increments during the dark period play an important role in promoting streamer‐to‐leader transition, except for temperature and the injected charge.

An SEU-hardened ternary SRAM design based on efficient ternary C-elements using CNTFET technology

Ternary logic has been investigated for several years as it can provide substantial advantages in reducing the complexity of operations and the number of interconnects. On the other hand, with the advancement of technology and the reduction of the feature size and supply voltage, the sensitivity of memory elements to radiation effects has increased. In this paper, a robust ternary SRAM (TSRAM) cell is designed using a novel ternary C-element based on carbon nanotube field-effect transistors (CNTFETs). Besides, a 2m×2n ternary memory array architecture is designed and simulated based on the proposed TSRAM cell. Unlike the previous TSRAM cells, our proposed cell is hardened against radiation effects caused by high-energy particle strikes, which is a significant achievement in ternary memory design. Our extensive simulations demonstrate that the proposed radiation-hardened TSRAM offers up to 77× higher critical charge and up to 98 % higher SNM at the cost of 47 % to 65 % area overhead. It is also noteworthy that the proposed design only needs only two threshold voltages. Moreover, the proposed TSRAM is robust against the process and temperature variations. Our results emphasize that the proposed design is a milestone for designing high-performance, radiation-hardened, and robust ternary memory chips.