Reverse Phenomenon Research Articles

Amine Gas-Induced Reversible Optical Bleaching of Bismuth-Based Lead-Free Perovskite Thin Films.

Reversible optical property changes in lead-free perovskites have recently received great interest due to their potential applications in smart windows, sensors, data encryption, and various on-demand devices. However, it is challenging to achieve remarkable color changes in their thin films. Here, methylamine gas (CH3 NH2 , MA0 ) induced switchable optical bleaching of bismuth (Bi)-based perovskite films is demonstrated for the first time. By exposure to an MA0 atmosphere, the color of Cs2 AgBiBr6 (CABB) films changes from yellow to transparent, and the color of Cs3 Bi2 I9 (CBI) films changes from dark red to transparent. More interestingly, the underlying reason is found to be the interactions between MA0 and Bi3+ with the formation of an amorphous liquefied transparent intermediate phase, which is different from that of lead-based perovskite systems. Moreover, the generality of this approach is demonstrated with other amine gases, including ethylamine (C2 H5 NH2 , EA0 ) and butylamine (CH3 (CH2 )3 NH2 , BA0 ), and another compound, Cs3 Sb2 I9 , by observing a similar reversible optical bleaching phenomenon. The potential for the application of CABB and CBI films in switchable smart windows is investigated. This study provides valuable insights into the interactions between amine gases and lead-free perovskites, opening up new possibilities for high-efficiency optoelectronic and stimuli-responsive applications of these emerging Bi-based materials.

Mode transition mechanisms in semi-passive flapping-wing propulsion or energy extraction

To facilitate the smooth transition of operational modes in self-sustaining micro-thrusters, this study focuses on a device employing semi-passive flapping wings. Transient numerical methods are used to analyze the variation of flap energy acquisition and propulsion characteristics with pitching frequency, and the relationship between the dominant vortex structure and the force characteristics is analyzed by using the integral momentum theorem and the dynamic mode decomposition (DMD) method. The results indicate that, under the investigated operational conditions, with an increase in the pitching frequency, distinct wake evolution characteristics were observed. In the energy harvesting operational regime, the wake patterns manifest as 2P + mS, 2S + mS, and mS types. During the transitional phase from energy harvesting to propulsion, the wake patterns shift from 2S + mS to 2S transitional types, eventually leading to the manifestation of a reverse Karman vortex street (2S RBVK). In the propulsion operational regime, the wake patterns consist of a reverse Karman vortex street and asymmetric reverse Karman vortex street phenomena. Simultaneously, it was observed that the transition of flapping-wing performance from energy harvesting to propulsion conditions delays behind the transformation of vortex street structures. This delay is attributed to the necessity for the flapping-wing device to overcome its own resistance before generating a net effective propulsive force. The contributions of unsteady wake to thrust primarily encompass vortex thrust, thrust due to localized fluid acceleration, induced momentum force, and induced pressure force. As the pitching frequency increases, the influence of wake vortices on propulsion also intensifies. The contribution of wake vortices to flapping-wing propulsion is determined by the spatial distribution of Lamb vectors and localized fluid accelerations. The conclusions drawn from the dynamic modal analysis and reconstructed flow field analysis of wake vortices align with the findings of the investigation of wake vortices based on the integral momentum theorem.

Inverse thermodiffusion of active matter in temperature gradient systems

We have revealed an inverse thermodiffusion phenomenon for active particles under temperature gradient in one-species systems. This counterintuitive behavior is supported by numerical calculations as well as theoretical analyses. It is presented that the active particles flow from high-temperature to low-temperature regions when the self-driving force is small. On the contrary, the active particles can flow from low-temperature to high-temperature regions as long as the self-driving force is large enough. The mass current reversal phenomenon can be explained analytically from the special swimming pressures of the active particles. The P é clet numbers defined in our work indicate a potential application in separating the particles with different activities. The findings may bring a new understanding of the physical properties of active matter and provide enlightenment for the study of the non-equilibrium collective transport of active particles.

Investigation of the lithiation mechanism of tin phosphite SnHPO3 as anode for Lithium-ion batteries

Phosphite-based anodes are attracting increasing attention in energy storage, especially for lithium-ion technology, due to their distinctive structures and their good electrochemical performances. Herein, the lithiation mechanism of tin phosphite SnHPO3 as lithium anode was examined for the first time. SnHPO3 has been synthesized through a soft hydrothermal route. Its structure was characterized by X-ray diffraction, Fourier Transform Infrared spectroscopy and 31P Nuclear Magnetic Resonance spectroscopy techniques. The reaction mechanisms of lithiation-delithiation of SnHPO3 anode was conducted using operando X-ray diffraction, ex-situ X-ray and ex-situ Fourier Transform Infrared spectroscopy techniques at room temperature. Both in-situ and ex-situ measurements show that SnHPO3 undergoes a conversion mechanism. The lithiation-delithiation of tin phosphite took place in a complex redox reaction sequence, and the reversible electrochemical phenomenon exclusively occurs through the alloying of tin at a low potential. The lithiation of tin phosphite begins by partial degradation of its structure, signifying the start of the conversion process. Then, the phosphite matrix becomes amorphous. The reversible capacity of the system is governed by the lithium‑tin alloying de-alloying process, produced at low potential.

Consequences of variable wall permeability and magnetic field on non-isothermal flow in converging/diverging tubes

The current article is devoted to the development of a theoretical model investigating heat transfer analysis of MHD blood flow through renal tubules. For this purpose, we consider the transport of Newtonian fluid inside a non-uniform tube whose lateral surface is kept at constant temperature. The walls of tube are considered to admit the variable permeation and the flow is actuated by an externally applied magnetic field. The solution of the problem is formulated analytically in terms of axial and radial velocities and temperature distribution under the presumption of lubrication approximation in the inertia free flow field. Implication of Darcy’s law for fluid seepage across the tubular membrane results in an ordinary differential equation having variable coefficients for the unknown pressure, which is successfully computed numerically using RK45 routine. Performance of velocity, pressure and temperature distributions has been investigated for various values of the physical parameters involving in the model. Moreover, flow rate behavior, fluid reabsorption and the leakage flux has been analyzed through graphs and tables. The characteristics of heat transfer in the flow field is also evaluated for various values of Brinkman number. A significant discovery reported in the results of present model reveals that the axial flow exhaustion and radial flow reversal are significantly influenced by the tube converging/diverging parameter and the Hartmann number as well. By employing a strong magnetic field, exhaustion and reversal phenomena in the flow field can be restrained up to a certain limit. Moreover, with an increasing wall permeability, there is a significant exhaustion of axial flow in a divergent tube and a prominent assistance takes place in the radial flow reversal for convergent tube. It is hoped that the present model will bear the potential to study flow in renal tubules and in hemodialyzer.

Significance of tumor size and number of positive nodes in patients with FIGO 2018 stage IIIC1 cervical cancer.

This study aimed to investigate the prognostic significance of tumor size and number of positive pelvic lymph nodes (PLN) in International Federation of Gynecology and Obstetrics (FIGO) 2018 stage IIIC1 cervical cancer patients. Clinical data from 626 women with cervical cancer treated at Osaka International Cancer Center in 2010-2020 were retrospectively reviewed. Using the cutoff value obtained on the receiver operating characteristic analysis, the prognostic significance of tumor size and number of positive PLN in stage IIIC1 patients was first evaluated via uni- and multivariate analyses. Then, the impact of incorporating tumor size and number of positive PLN into the FIGO staging system was investigated using the Kaplan-Meier method. Among 196 women with Stage IIIC1 disease, larger tumors (>4cm) and multiple PLN metastases (≥4) were independent predictors of progression-free survival (PFS) in patients with stage IIIC1 cervical cancer. The PFS of patients with stage IIIC1 disease was inversely associated with the number of risk factors. Although patients with stage IIIC1 disease had significantly increased survival rates compared to those with stage IIIA or IIIB disease in the original FIGO 2018 staging system, this reversal phenomenon was resolved by incorporating larger tumors (>4cm) and multiple PLN metastases (≥4) into the revised staging system. Incorporating tumor size and number of metastatic lymph nodes into the FIGO staging system allows additional risk stratification for women with stage IIIC1 cervical cancer and improves survival prediction performance.

Investigation of Reverse Recovery Phenomenon for SiC MOSFETs in High-Temperature Applications

Investigation of Reverse Recovery Phenomenon for SiC MOSFETs in High-Temperature Applications

Demonstration of Pavlov Associative Memory by Implementation of Rate Coding Using Magnetic Tunnel Junction Neurons

In this paper, a fully functioning Pavlov associative memory system, one of the most famous examples of the biological brain function, is implemented by a basis of rate coding. In order to create a neural signal which is capable of emulating the synaptic weight based on rate coding, a neural signal is constructed by utilizing telegraphic switching of the magnetic tunnel junction (MTJ), a random magnetization reversal phenomenon. Spike rate of the MTJ neuron is controllable by adjusting the STT current bias, creating signals with rate information that is capable of implementing rate coding scheme as a weight update method for the TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> memristor synapse. The proposed neuron creates random spike signals containing rate information, which participates in emulating Pavlov associative memory characteristics such as learning and forgetting, as well as rate controlling characteristics. The suggested structure shows a coding scheme which both input and output neurons participate, which can be expanded to larger neuromorphic neural network applications.

Growth, sex reversal pattern, and reproductive characteristics of Barramundi (Lates calcarifer) broodstock candidates reared in floating cages

Sex reversal of male to female is a characteristic of barramundi (Lates calcarifer), which is affected by several factors, thereby changing the broodstock population. A study was conducted in floating cages in Langkawi, Malaysia, to determine the weight point at the onset of the sex reversal phenomena. A total of 75 female and 55 male adult individuals (3–4 weeks of age) were sampled from the fish cultured in cages to ascertain their sex at different weights. The water temperature and salinity values were 29.82 °C and 33.12 ppt, respectively. The specimens were classified into twelve bodyweight classes (2.00–8.00 ± 0.5 kg intervals). Female specimen body weight distribution was highest in the 6.01–6.50 kg class (22.6%), followed by the 5.51–6.00 kg and 4.51–5.00 class (13.3%), while male specimen body weight distribution was highest in the 4.51–5.00 kg class (32.1%), followed by the 4.01–4.50 kg class (30.3%). Length-to-weight relationships for females and males of Asian Seabass indicated positive allometric growth. The correlation between body weight and GSI, using Pearson’s correlation, for both sexes, for the male and female barramundi, there was a weak correlation between body weight and GSI, which was 37 and 30%, respectively. Based on the present study’s findings, it can be concluded that sex reversal from male to female in Barramundi largely occurred at 4.57 kg body weight and 66.8 cm total length.

Analysis of a parallel-channel natural circulation loop in the passive residual heat removal system of the NHR200-II reactor

The passive residual heat removal (PRHR) system of the NHR200-II nuclear heating reactor is a parallel-channel single-phase natural circulation loop. The reverse-flow phenomenon in parallel-channel natural circulation loops will cause insufficient heat removal capacity in the PRHR system. In this study, a simplified mathematical model was established for the PRHR system of NHR200-II. The mechanism of the reverse flow phenomenon in the PRHR system was analyzed using a pressure drop-flow rate diagram, and the effects of cooler elevation and loop resistance on the number of reverse flow branches were discussed. The analysis reveals that the reverse flow phenomenon of the PRHR system can be suppressed by increasing the elevation of the air cooler. Furthermore, there exists a critical elevation of the air cooler. It is not feasible to suppress the reverse flow by changing the friction coefficients of either the PHE branches or the air cooler branch when the air cooler elevation is less than the critical value. Oppositely, the number of reverse flow branches can be reduced or even eliminated by increasing the resistance of the PHE branches or reducing the resistance of the air cooler branch when the air cooler elevation is greater than the critical value.

Deletions within intronic T-DNA lead to reversion of T-DNA mutant phenotypes.

Agrobacterium-mediated transformation enables random transfer-DNA (T-DNA) insertion into plant genomes. T-DNA insertion into a gene's exons, introns or untranscribed regions close to the start or stop codon can disrupt gene function. Such T-DNA mutants have been useful for reverse genetics analysis, especially in Arabidopsis thaliana. As T-DNAs are inserted into genomic DNA, they are generally believed to be stably inherited. Here, we report a phenomenon of reversion of intronic T-DNA mutant phenotypes. From a suppressor screen using intronic T-DNA pi4kβ1,2 double mutant, we recovered intragenic mutants of pi4kβ1, which suppressed the autoimmunity of the double mutant. These mutants carried deletions in the intronic T-DNAs, resulting in elevated transcription of normal PI4Kβ1. Such reversion of T-DNA insertional mutant phenotype stresses the need for caution when using intronic T-DNA mutants and reiterates the importance of using irreversible null mutant alleles in genetic analyses.

On the Nature of Post‐Constrained Recovery Residual Stress of NiTi Shape Memory Alloys

In this article, the nature of the post‐constrained recovery residual stress (PCRRS) observed in nickel titanium (NiTi) shape memory alloys (SMAs) subjected to constrained recovery and returned to a low‐temperature state while remaining constrained is investigated. After performing the thermomechanical cycling to produce the PCRRS state, four experiments are performed with different deflection profiles applied from the PCRRS state, and the changes in the residual stress is observed. All tests produce a gradual decrease in stress after every load cycle, similar to cyclic softening. However, repetition of the process used to initially generate PCRRS restores the initial magnitude of the PCRRS, indicating that the decrease in residual stress is a stable, repeatable, and reversible phenomenon, and not true material degradation. To better understand the nature of PCRRS, an analysis is performed comparing the modulus relating stress and strain at different points along the thermomechanical loading path. In this analysis, it is shown that NiTi has a combination of twinned and detwinned martensite in the PCRRS state. Understanding the nature of PCRRS, properties and its stability have the potential for advanced engineering applications such as self‐healing and fatigue‐resistant materials by generating stresses without continuous actuation over a long period of time.

Concentration mediated structural modulation in a family of mixed-ligand coordination polymers: Structure, sorption and luminescence study

A series of mixed-ligands Zn(II) coordination polymers (CPs) have contracted by varying the relative ratio of two ligands. A linear N,N′-donor ligand, trans 4,4′-azobispyridine (azbpy) and a sodium salt of tri carboxylic acid, 1,3,5-benzenetricarboxylate (Na3btc) have been used in different ratio, along with Zn(II) salt to synthesize three different mixed ligands multifunctional hydroxy bridged CPs, namely {[Zn2(μ2-OH)(azbpy)(btc)(H2O)]. (H2O)(MeOH)}n (1), {[Zn2(μ3-OH)(azbpy)1.5(btc)(H2O)].(azbpy)0.5(H2O)4}n (2), and {[Zn2.5(azbpy)(Hbtc)2(μ2-OH)(H2O)3].(H2O)3.5(MeOH)}n (3). All these CPs 1, 2 and 3 have been characterized by single crystal X-ray diffraction (SCXRD), elemental analysis, infrared (IR) spectroscopy, thermogravimetric (TG) analysis, UV–visible spectroscopy and powder X-ray diffraction (PXRD). The desolvated frameworks of 1 and 2 adsorb CO2 better, over N2, whereas, complex 3 shows reverse phenomenon. Solid state luminescence studies of these CPs display attentive fluorescence emission at room temperature. Change in those properties has been observed, which has been discussed here with structural correlation.

Reversed charge transfer induced by nickel in Fe-Ni/Mo2C@nitrogen-doped carbon nanobox for promoted reversible oxygen electrocatalysis

The interaction between metal and support is critical in oxygen catalysis as it governs the charge transfer between these two entities, influences the electronic structures of the supported metal, affects the adsorption energies of reaction intermediates, and ultimately impacts the catalytic performance. In this study, we discovered a unique charge transfer reversal phenomenon in a metal/carbon nanohybrid system. Specifically, electrons were transferred from the metal-based species to N-doped carbon, while the carbon support reciprocally donated electrons to the metal domain upon the introduction of nickel. This led to the exceptional electrocatalytic performances of the resulting Ni-Fe/Mo2C@nitrogen-doped carbon catalyst, with a half-wave potential of 0.91 V towards oxygen reduction reaction (ORR) and a low overpotential of 290 mV at 10 mA cm−2 towards oxygen evolution reaction (OER) under alkaline conditions. Additionally, the Fe-Ni/Mo2C@carbon heterojunction catalyst demonstrated high specific capacity (794 mA h gZn−1) and excellent cycling stability (200 h) in a Zn-air battery. Theoretical calculations revealed that Mo2C effectively inhibited charge transfer from Fe to the support, while secondary doping of Ni induced a charge transfer reversal, resulting in electron accumulation in the Fe-Ni alloy region. This local electronic structure modulation significantly reduced energy barriers in the oxygen catalysis process, enhancing the catalytic efficiency of both ORR and OER. Consequently, our findings underscore the potential of manipulating charge transfer reversal between the metal and support as a promising strategy for developing highly-active and durable bi-functional oxygen electrodes.

Not Asian Anymore: Reconstruction of the History, Evolution, and Dispersal of the "Asian" Lineage of CPV-2c.

Variability has been one of the hallmarks of canine parvovirus type 2 (CPV-2) since its discovery, and several lineages and antigenic variants have emerged. Among these, a group of viruses commonly called Asian CPV-2c has recently been reported with increasing frequency in different regions. Currently, its global epidemiology and evolution are essentially unknown. The present work deals with this information gap by evaluating, via sequence, phylodynamic, and phylogeographic analyses, all the complete coding sequences of strains classified as Asian CPV-2c based on a combination of amino acid markers and phylogenetic analysis. After its estimated origin around 2008, this lineage circulated undetected in Asia until approximately 2012, when an expansion in viral population size and geographical distribution occurred, involving Africa, Europe, and North America. Asia was predicted to be the main nucleus of viral dispersal, leading to multiple introduction events in other continents/countries, where infection establishment, persistence, and rapid evolution occurred. Although the dog is the main host, other non-canine species were also involved, demonstrating the host plasticity of this lineage. Finally, although most of the strains showed an amino acid motif considered characteristic of this lineage, several exceptions were observed, potentially due to convergent evolution or reversion phenomena.

Advancements in Blood Rheology and Hemodynamics Simulation with a Brief History

Blood rheology is a complex field of study that investigates blood flow behavior, vital for understanding its role in physiological and pathological conditions. This article delves into various rheological models that describe blood behavior, ranging from Generalized Newtonian models to more sophisticated thixotropic and elastoviscoplastic models. One such model, the Horner-Armstrong-Wagner-Beris (HAWB) model, offers valuable insights into the dynamic interplay of reversible and irreversible phenomena in blood flow. Recent advancements, such as the mHAWB framework, provide enhanced accuracy and versatility in modeling blood rheology, holding great potential for diagnostic and therapeutic applications. Moreover, microscopic and mesoscopic simulations have paved the way for deeper insights into blood behavior, bridging the gap between theory and experiment. Multiscale models offer a promising approach to capturing the complexities of blood rheology at various length scales. Finally, we explore the clinical implications of blood rheology, including its significance in conditions like polycythemia, neonatal respiratory distress, and circulatory inadequacy. By understanding blood rheology comprehensively, we can advance our knowledge of complex blood flow dynamics and its potential applications in healthcare.

First-principles study on the magnetic properties in non-metallic co-doped cubic LaNiO3

Using the first principles spin polarized calculations, the electronic structures and magnetic properties of two C atoms and two S atoms doped LaNiO3 (LNO) are investigated. For the double C-doped LNO (C-LNO), C–O–C chain exhibits the ferromagnetic (FM) order arrangement. The introduction of C atoms increases the average magnetic moment of each Ni atom by 0.23 μB/cell and enhances the hybridization between Ni-3d and O-2p states. The C atom generates a weak magnetic moment of 0.07 μB/atom due to the magnetization in the FM ground state. For the case of double S-doped LNO (S-LNO), S–O–S chain exhibits the antiferromagnetic (AFM) order. In the ferromagnetic configuration of S-LNO, each S atom generates a magnetic moment of 0.18 μB/atom due to the Ni–O hybridization. In addition, the interesting phenomenon of magnetic moment reversal of S atoms is observed in both the FM and AFM structures of S-LNO.

The Investigation into the Extent of Investors Irrationality Based on GARCH-M Model

Research in risk preference suggests that, in violation of economic man hypothesis, most investors are economically irrational, which is reflected through the phenomenon of preference reversal. However, there is a scant of study to measure the extent how irrational individuals are. Inspired by the way how efficient market is defined, this paper proposes a measurement of preference reversal and divides irrationality into two types. Furthermore, based on the data of market index and GARCH-M model, this paper finds that risk preference inconsistency always exists and investors in smooth time are weakly irrational.

PIV-based experiments on reverse flow characteristics in an equal-height-difference passive heat removal system for ocean nuclear power plants

The equal-height-difference passive heat removal system (EHDPHRS) has a large potential in floating nuclear power plants (FNPPs) due to its ability to fully utilize the marine environment to achieve residual heat removal. However, the horizontal connection between the heat sink and the heat source could easily lead to the subcooled-water reverses flow and thus trigger serious flow instabilities. In the present paper, a fully visualized experimental set was built, combined with a particle image velocity (PIV) system to investigate the subcooled-water reverses flow in the EHDPHRS. First, PIV observations clearly highlighted five flow stages during a complete natural circulation, including the reverse flow occurred in the single-phase and two-phase flow. Then, it was shown that the single-phase reverse velocity is proportional to heating power and inversely proportional to subcooled-water temperature. While, the two-phase reverse velocity increases first and then decreases with the increase in heating power. Moreover, the two-phase reverse flow phenomenon shows obvious periodicity. Finally, the buoyancy force (Fb) caused by the density contrast, and the pressure difference (FΔP) caused by the direct contact condensation (DCC) are the triggering forces for the reverse flow, while the flow inertia force (Fi) caused by the forward flow represents the restraining force.

Optimization Research on DC Air Circuit Breaker at High Altitudes Based on Arc Root Stagnation and Arc Reverse Movement Phenomena

Optimization Research on DC Air Circuit Breaker at High Altitudes Based on Arc Root Stagnation and Arc Reverse Movement Phenomena