bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental investigation and thermodynamic analysis of application of hybrid nanofluid in a parabolic solar trough collector
Authors: Wang He , Abed Azher M. , Beemkumar N. , Kumar Ambati Vijay , Ayed Hamdi , Mouldi Abir , Shamel Ali
Published: May 2024

In this research, thermal modeling has been done to investigate the effect of nanofluid on the performance of the linear parabolic collector. Therminol vapor/liquid phase fluid (VP-1) has been used as a base fluid; iron oxide nanoparticles have been used to produce mono-nanofluid; and iron oxide multi-walled carbon nanotubes nanocomposite has been used as nanoparticles to produce hybrid nanofluid. The fluid flow inside the absorber tube of the collector is assumed to be turbulent. The results show that when hybrid nanofluid and mono-nanofluid are used, the energy and exergy efficiencies of the collector are higher than those for the conditions of using the base fluid, but their amount is slightly lower with the use of hybrid nanofluid than when the working fluid is mono-nanofluid. According to the obtained results, the highest energy efficiency of the linear parabolic collector using nanofluid and mono-nanofluid is 70.2% and 70.4%, respectively, and the highest exergy efficiency is 35.7% and 35.9%, respectively. Despite this, the friction coefficient of mono-nanofluid compared to hybrid nanofluid was obtained on average about 9% higher. The results showed that the criterion for evaluating the performance of the collector (hydrodynamic thermal efficiency) when hybrid nanofluid is used is more than when mono-nanofluid is used.
Superconducting quantum memory with a suspended coaxial resonator
Authors: Krayzman Lev , Lei Chan U , Ganjam Suhas , Teoh James , Frunzio Luigi , Schoelkopf Robert J.
Published: May 2024

A promising way to store quantum information is by encoding it in the bosonic excitations of microwave resonators. This provides for long coherence times, low dephasing rates, as well as a hardware-efficient approach to quantum error correction. There are two main methods used to make superconducting microwave resonators: by traditionally machining them out of bulk material and by lithographically fabricating them on a chip in thin film. 3D resonators have few loss channels and larger mode volumes, and therefore smaller participations in the lossy parts, but it can be challenging to achieve high material quality. On-chip resonators can use low-loss thin films, but they confine the field more tightly, resulting in higher participations and additional loss channels from the dielectric substrate. In this work, we present a design in which a dielectric scaffold supports a thin-film conductor within a 3D package, thus combining the low surface participations of bulk-machined cavities with high quality and control over materials of thin-film circuits. By incorporating a separate chip containing a transmon qubit, we realize a quantum memory and measure single-photon lifetimes in excess of a millisecond. This hybrid 3D architecture has several advantages for scaling as it relaxes the importance of the package and permits modular construction with separately replaceable qubit and resonator devices.
Collective control of a vortex array in a ferroelectric ultrathin film
Authors: Ruan Bo , Xiong Pengcheng , Liu Qingyuan , Ji Ye , Yuan Shuai
Published: May 2024

Recently, the observation of ferroelectric vortex arrays has triggered the investigation of topological domain structures and their characteristics. Vortices are typical topological domain structures with chirality in nanoscale ferroelectric materials. The chirality of a single vortex in a nanodot can be easily manipulated, but the collective control of a vortex array is exceptionally difficult and has not yet been realized. This Letter proposes an effective scheme for the collective control of a vortex array and investigates it via phase-field simulations. The results indicate that the collective control of a vortex array with bidirectional switching can be realized by introducing a bending film with periodic large curvatures under alternative electric fields. Furthermore, a general rule for determining the electrically controllable chirality of ferroelectric vortices is proposed. This Letter demonstrates the feasibility of the collective control of vortex arrays and provides insights for developing ferroelectric nanoelectronic devices based on vortex arrays.
Structural heterogeneity and plasticity of a Zr-based metallic glass modulated by high-temperature deformation
Authors: Lu Wenting , Huang Bo , Liao Shansi , Liu Penghua , Lv Hui , Wu Jiayi , Yi Jun , Wang Qing , Wang Gang
Published: May 2024

Metallic glasses (MGs) are of high strength but limited plasticity at room temperature (RT) due to localized shear in the intrinsically heterogeneous structure. Here, we investigate the variation of structural heterogeneity and plasticity of a Zr-based MG after high-temperature (T) tension under different stresses (σ) at 579 K (0.9Tg, where Tg is the glass transition temperature). The correlation length (ξ) of the heterogeneous structure and the average Young's modulus (E¯) increase with σ when σ is below 160 MPa; when σ exceeds 160 MPa, both ξ and E¯ decrease with σ, leading to the improvement of the plasticity. This research could be enlightening for improving the plasticity of MGs at RT through tuning their structural heterogeneity with high-T deformation.
Giant polarization in tetragonal-like BiFeO3 film via (Ba,Ca)TiO3 doping
Authors: Li Teng , Zhu Beibei , Zhuo Hao , Hu Shudong , Liu Yiwen , Shao Botao , Wang Ke , Song Dongsheng , Xu Liqiang , Chen Feng
Published: May 2024

BiFeO3 is a multiferroic material, its tetragonality (T) phase usually exhibits large tetragonality (c/a ratio) and strong ferroelectricity. Unlike the commonly used method of strain engineering via substrate, here we present a general and practical approach for obtaining T-like phase BiFeO3 films through (Ba,Ca)TiO3 doping (BF-BCT). The BF-BCT film coherently grows on the La0.7Sr0.3MnO3/(La0.18Sr0.82)(Al0.59Ta0.41)O3 (001) substrate even at 180 nm thick, implying a very large critical thickness, and shows a large tetragonality of 1.12. Impressively, the films exhibit a giant remanent polarization (2Pr) of 320 μC/cm2, which is higher than the corresponding values of any other lead-free ferroelectric films reported to date. Cross-sectional scanning transmission electron microscopy measurements confirm the presence of the T-like phase in BF-BCT films, where the giant polarization might be attributed to the off-center B-site atom. The BF-BCT films are structurally homogeneous without any precipitation of the second phase. The giant polarization observed in the BF-BCT films indicate their great potential for application in next-generation storage and information devices.
Edge passivation: Considerable improvement in photovoltaic performance of perovskite/silicon tandem solar cells
Authors: Chen Bingbing , Cui Mengnan , Wang Xinru , Meng Hao , Bai Yuhua , Li Wenheng , Wang Xiao , Zhang Xuning , Chen Jianhui
Published: May 2024

Edge recombination is considered hard to avoid entirely in silicon (Si) solar cells as well as Si-base solar devices, hindering their future commercialization. However, such an important issue in perovskite/silicon (PK/Si) tandem solar cells has not attracted much attention. Herein, a low-temperature, non-vacuum liquid-based edge passivation strategy (LEPS) to improve the power conversion efficiency (PCE) of PK/Si tandem solar cells is proposed. The minority carrier lifetime (τeff) of the PK/Si tandem sample with 495.8 μs significantly enhances to 739.7 μs after passivating the Si sub-cell edge recombination. The open circuit voltage (VOC) of the PK/Si tandem solar cell increases by up to +3.8%abs from the initial state after LEPS treatment due to edge passivation, leading to the PCE of the PK/Si tandem solar cell increases by up to +1.2%abs. Finally, a monolithic PK/Si tandem cell with a PCE of 29.48% was achieved by further utilizing the LEPS, which opened up a simple and effective avenue for enhancing the PCE of PK/Si tandem solar cells and further promoting a higher photovoltaic output power of tandem modules.
Mixed strategy approach destabilizes cooperation in finite populations with clustering coefficient
Authors: Si Zehua , He Zhixue , Shen Chen , Tanimoto Jun
Published: May 2024

Evolutionary game theory, encompassing discrete, continuous, and mixed strategies, is pivotal for understanding cooperation dynamics. Discrete strategies involve deterministic actions with a fixed probability of one, whereas continuous strategies employ intermediate probabilities to convey the extent of cooperation and emphasize expected payoffs. Mixed strategies, though akin to continuous ones, calculate immediate payoffs based on the action chosen at a given moment within intermediate probabilities. Although previous research has highlighted the distinct impacts of these strategic approaches on fostering cooperation, the reasons behind the differing levels of cooperation among these approaches have remained somewhat unclear. This study explores how these strategic approaches influence cooperation in the context of the prisoner’s dilemma game, particularly in networked populations with varying clustering coefficients. Our research goes beyond existing studies by revealing that the differences in cooperation levels between these strategic approaches are not confined to finite populations; they also depend on the clustering coefficients of these populations. In populations with nonzero clustering coefficients, we observed varying degrees of stable cooperation for each strategic approach across multiple simulations, with mixed strategies showing the most variability, followed by continuous and discrete strategies. However, this variability in cooperation evolution decreased in populations with a clustering coefficient of zero, narrowing the differences in cooperation levels among the strategies. These findings suggest that in more realistic settings, the robustness of cooperation systems may be compromised, as the evolution of cooperation through mixed and continuous strategies introduces a degree of unpredictability.
High heat transfer plant-inspired neural network structure controlled by variable magnetic field
Authors: Li Dachao , Shi Taisen , Li Jianhua , Li Chunling , Shi Zhifeng , Gu Tongkai
Published: May 2024

Efficient heat dissipation and thermal protection present urgent challenges in high-power integrated circuits (ICs). Although applying a coating of highly thermally conductive materials on the surface of ICs is anticipated to mitigate heat concentration issues, ensuring thermal protection for adjacent devices continues to pose a challenge. Inspired by the microstructure of unidirectional nutrient transport in plant roots, this study utilizes magnetic liquid metal droplets to develop a high thermal conductivity network capable of adaptively manipulating the heat transfer path. This approach aims to tackle the challenges of heat concentration, disordered thermal dissipation, and thermal protection for high-power ICs, thereby enhancing thermal management efficiency. By controlling the distribution of the magnetic field, this study orchestrates the structure of the thermal conduction network to ensure rapid and orderly heat dissipation of ICs while simultaneously validating the network's thermal protection performance. The temperature in the IC thermal concentration zone reaches thermal equilibrium at 399.1 K when the ambient temperature is at 295 K. As the ambient temperature rises to 333 K, the temperature in the IC heat concentration zone stabilizes at approximately 400 K. Simultaneously, the temperature at a specific point in the thermal path of the network registers at 341 K, with the temperatures of the devices flanking this point at 314 K. The magnetron thermal conduction network, inspired by the root structure of bionic plants, not only boosts the thermal management efficiency of ICs but also shows promising application prospects in aerospace, electronics, and other related industries.
Radiationless decay spectrum of O 1s double core holes in liquid water
Authors: Trinter Florian , Inhester Ludger , Püttner Ralph , Malerz Sebastian , Thürmer Stephan , Marchenko Tatiana , Piancastelli Maria Novella , Simon Marc , Winter Bernd , Hergenhahn Uwe
Published: May 2024

We present a combined experimental and theoretical investigation of the radiationless decay spectrum of an O 1s double core hole in liquid water. Our experiments were carried out using liquid-jet electron spectroscopy from cylindrical microjets of normal and deuterated water. The signal of the double-core-hole spectral fingerprints (hypersatellites) of liquid water is clearly identified, with an intensity ratio to Auger decay of singly charged O 1s of 0.0014(5). We observe a significant isotope effect between liquid H2O and D2O. For theoretical modeling, the Auger electron spectrum of the central water molecule in a water pentamer was calculated using an electronic-structure toolkit combined with molecular-dynamics simulations to capture the influence of molecular rearrangement within the ultrashort lifetime of the double core hole. We obtained the static and dynamic Auger spectra for H2O, (H2O)5, D2O, and (D2O)5, instantaneous Auger spectra at selected times after core-level ionization, and the symmetrized oxygen-hydrogen distance as a function of time after double core ionization for all four prototypical systems. We consider this observation of liquid-water double core holes as a new tool to study ultrafast nuclear dynamics.
Numerical analysis of heat transfer characteristics in ribbed two-passed channel with varied cross section
Authors: Li Minghao , Luo Lei , Yang Siyuan , Yan Han , Du Wei , Zhou Xun
Published: May 2024

The mid-chord region of turbine blades typically employs internal cooling channels to enhance heat transfer. However, traditional internal cooling channels are mostly designed in the form of straight channels, and studies based on it may not address the needs of variable cross section channels. Therefore, this study investigates the effect of rib configurations in variable cross section channels on channel performance. First, the cross sectional area of the two-passed channels is modified by altering the inclination angle of the dividers (−3°, 0°, and +3°). The flow pattern and heat transfer features within a two-passed channel with variable cross section under four different rib configurations of NP, NN, PN, and PP are investigated using numerical simulation. N denotes the ribs rotated 45° clockwise relative to the flow direction, while P denotes the ribs rotated 45° counterclockwise. Subsequently, the optimal rib configuration within the variable cross sectional two-passed channels is determined for Reynolds numbers ranging from 10 000 to 50 000. Results show that, at +3°, the PP exhibits the maximum decrease of up to 18.2% in transfer performance factor (TPF), while at −3°, the NN shows the maximum decrease of up to 12.7%. It is evident that the optimal rib configuration for two-passed channels under different divider inclinations is not consistent. At +3°, the NP exhibits the best TPF, while at −3°, the PP demonstrates the optimal TPF. This study provides insights into selecting appropriate rib configurations when the cross sectional area of internal channels within turbine blades varies. Compared to the studies that have focused on traditional straight channels, the research provides guidance for the design of ribbed two-passed channels with varied cross section.
Gas physisorption impact on prolate dust in free-molecule flows: A static study
Authors: Yu Hsin-Chen , Zhang Xiaoping , Wu Lei , Ren Zhongzhou , He Peishan
Published: May 2024

Gas–solid coupling systems operating at low pressure or the micro/nanoscale generally exist in nature and industrial manufacture. Although the gas-scattering model has been widely used to study this problem on the dust surface, the consideration of gas physisorption was often neglected in previous applications of gas–surface scattering models. Therefore, this study aims to investigate the distribution of gas physisorption on the dust surface and assess its impact on the static force experienced by nonspherical dust in free-molecule flows. In this study, the prolate dust spinning around its minor axis is considered and the in-house direct simulation Monte Carlo code is used. Results show that gas physisorption on prolate dust is influenced by changes in gas number densities, Mach number, and dust shape. Furthermore, the gas physisorption enhances the gas–dust coupling for dust with a smooth surface at low gas pressure, attributed to the increasing ratio of Maxwell diffuse scattering of gas molecules on the gas-adsorbed part of the surface. Hence, gas physisorption was suggested as a potential factor for gas–dust coupling at low gas pressure.
Piston problem for the pressureless hydrodynamic traffic flow model
Authors: Wang Zhengqi , Guo Lihui , Wei Zhijian
Published: May 2024

The hydrodynamic model can be used to describe traffic problems in transport. When the speed of the first car is less than the speed behind it, it leads to traffic jams. When the first car's speed is faster than the cars behind it, it leads to traffic evacuation. If we consider the first car to be a piston, then the speed of the piston will cause traffic jams and traffic evacuation. In this paper, we study the piston problem for the hydrodynamic model. The formation and propagation of shock wave, rarefaction wave, delta-shock wave, and vacuum can describe the phenomena of traffic jams, traffic evacuation, severe traffic jams, and traffic evacuation with traffic volume of zero, respectively. Therefore, for different traffic phenomena, we prove the existence of shock solution, rarefaction solution, delta shock solution, and vacuum solution. In addition, we perform some representative numerical simulations.
The advancing wave front on a sloping channel covered by a rod canopy following an instantaneous dam break
Authors: Buono Elia , Katul Gabriel G. , Poggi Davide
Published: May 2024

The drag coefficient Cd for a rigid and uniformly distributed rod canopy covering a sloping channel following the instantaneous collapse of a dam was examined using flume experiments. The measurements included space x and time t high resolution images of the water surface h(x, t) for multiple channel bed slopes So and water depths behind the dam Ho along with drag estimates provided by sequential load cells. Using these data, an analysis of the Saint-Venant equation (SVE) for the front speed was conducted using the diffusive wave approximation. An inferred Cd=0.4 from the h(x, t) data near the advancing front region, also confirmed by load cell measurements, is much reduced relative to its independently measured steady-uniform flow case. This finding suggests that drag reduction mechanisms associated with transients and flow disturbances are more likely to play a dominant role when compared to conventional sheltering or blocking effects on Cd examined in uniform flow. The increased air volume entrained into the advancing wave front region as determined from an inflow–outflow volume balance partly explains the Cd reduction from unity.
A simple model for evaluating the performance of sparker source with multi-electrode array
Authors: Zhang Liancheng , Zhang Zhi , Ding Shengdi , Fu Qinhai , Xu Wenjie , Pei Yanliang
Published: May 2024

Sparker sources have been widely applied in high-resolution seismic explorations. However, to date, there exists no model that can directly predict the electro-acoustic characteristics of a sparker source with a multi-electrode array. In this Letter, we propose an analytical water-resistance model that yields a more accurate loop current. A simplified energy conservation model and the multi-bubble dynamics equations are used to evaluate the electro-acoustic process. Considering the bubble interaction will give a better prediction of multi-bubble dynamics. Regardless of the bubble interaction, the model is also able to obtain the desirable loop current and shockwave. Finally, with the influence of electrode considered, we use the model to evaluate the performance of a 50 × 8 array. The modeling results agree well with the field trials.
The untold history of banana bunchy top disease
Authors: Geering Andrew D. W.
Published: May 2024

Of all the plant diseases that occur in Australia, banana bunchy top disease would rank high on any list of those that have had the greatest impact on society. Bunchy top first became a major problem in Australia during World War 1 in the Tweed Valley in New South Wales, close to the border of Queensland. The Soldier Settlement Scheme was initiated to provide a livelihood for returned soldiers, and the Northern Rivers region of New South Wales was chosen as the site for a new subtropical fruit industry. Physically and psychologically damaged men were encouraged to settle on the land to grow bananas, only to be left in ruins within two years because bunchy top had destroyed their plantations. Bunchy top did not discriminate, and many other well-established growers also ‘went broke’. The cries for assistance from the banana growers made it to the federal Parliament in Melbourne, and a Bunchy Top Investigation Committee was formed in 1924 with funding equally contributed by the New South Wales, Queensland, and Australian Governments. Charles Magee was the full-time plant pathologist appointed to the investigation, and he did most of the research. Most histories of the bunchy top research program follow the written accounts of Magee, but he only provided a narrow perspective. Several of the major hypotheses about the epidemiology of bunchy top disease, such as that it was spread in the plant’s suckers and was vectored by the banana aphid Pentalonia nigronervosa, were established by growers such as William John (aka Jack) Burton Marks well before the Bunchy Top Investigation Committee began. This paper describes the beginnings of the subtropical banana industry, the introduction of bunchy top disease, and efforts by the scientific and farming communities to find a preventative treatment or cure for the disease.
Neuronal PAS domain 1 identifies a major subpopulation of wakefulness-promoting GABAergic neurons in the basal forebrain
Authors: Troppoli Timothy A. , Yang Chun , Katsuki Fumi , Uygun David S. , Lin Ilyan , Aguilar David D. , Spratt Tristan , Basheer Radhika , McNally James M. , Savio Chan C. , McKenna James T. , Brown Ritchie E.
Published: May 2024

Here, we describe a group of basal forebrain (BF) neurons expressing neuronal Per-Arnt-Sim (PAS) domain 1 (Npas1), a developmental transcription factor linked to neuropsychiatric disorders. Immunohistochemical staining in Npas1-cre-2A-TdTomato mice revealed BF Npas1
+
neurons are distinct from well-studied parvalbumin or cholinergic neurons. Npas1 staining in GAD67-GFP knock-in mice confirmed that the vast majority of Npas1
+
neurons are GABAergic, with minimal colocalization with glutamatergic neurons in vGlut1-cre-tdTomato or vGlut2-cre-tdTomato mice. The density of Npas1
+
neurons was high, five to six times that of neighboring cholinergic, parvalbumin, or glutamatergic neurons. Anterograde tracing identified prominent projections of BF Npas1
+
neurons to brain regions involved in sleep–wake control, motivated behaviors, and olfaction such as the lateral hypothalamus, lateral habenula, nucleus accumbens shell, ventral tegmental area, and olfactory bulb. Chemogenetic activation of BF Npas1
+
neurons in the light period increased the amount of wakefulness and the latency to sleep for 2 to 3 h, due to an increase in long wake bouts and short NREM sleep bouts. NREM slow-wave and sigma power, as well as sleep spindle density, amplitude, and duration, were reduced, reminiscent of findings in several neuropsychiatric disorders. Together with previous findings implicating BF Npas1
+
neurons in stress responsiveness, the anatomical projections of BF Npas1
+
neurons and the effect of activating them suggest a possible role for BF Npas1
+
neurons in motivationally driven wakefulness and stress-induced insomnia. Identification of this major subpopulation of BF GABAergic neurons will facilitate studies of their role in sleep disorders, dementia, and other neuropsychiatric conditions involving BF.
Interspecific transfer of genetic information through polyploid bridges
Authors: Kauai Felipe , Bafort Quinten , Mortier Frederik , Van Montagu Marc , Bonte Dries , Van de Peer Yves
Published: May 2024

Hybridization blurs species boundaries and leads to intertwined lineages resulting in reticulate evolution. Polyploidy, the outcome of whole genome duplication (WGD), has more recently been implicated in promoting and facilitating hybridization between polyploid species, potentially leading to adaptive introgression. However, because polyploid lineages are usually ephemeral states in the evolutionary history of life it is unclear whether WGD-potentiated hybridization has any appreciable effect on their diploid counterparts. Here, we develop a model of cytotype dynamics within mixed-ploidy populations to demonstrate that polyploidy can in fact serve as a bridge for gene flow between diploid lineages, where introgression is fully or partially hampered by the species barrier. Polyploid bridges emerge in the presence of triploid organisms, which despite critically low levels of fitness, can still allow the transfer of alleles between diploid states of independently evolving mixed-ploidy species. Notably, while marked genetic divergence prevents polyploid-mediated interspecific gene flow, we show that increased recombination rates can offset these evolutionary constraints, allowing a more efficient sorting of alleles at higher-ploidy levels before introgression into diploid gene pools. Additionally, we derive an analytical approximation for the rate of gene flow at the tetraploid level necessary to supersede introgression between diploids with nonzero introgression rates, which is especially relevant for plant species complexes, where interspecific gene flow is ubiquitous. Altogether, our results illustrate the potential impact of polyploid bridges on the (re)distribution of genetic material across ecological communities during evolution, representing a potential force behind reticulation.
Three-component systems represent a common pathway for extracytoplasmic addition of pentofuranose sugars into bacterial glycans
Authors: Kelly Steven D. , Duong Nam Ha , Nothof Jeremy T. , Lowary Todd L. , Whitfield Chris
Published: May 2024

Cell surface glycans are major drivers of antigenic diversity in bacteria. The biochemistry and molecular biology underpinning their synthesis are important in understanding host–pathogen interactions and for vaccine development with emerging chemoenzymatic and glycoengineering approaches. Structural diversity in glycostructures arises from the action of glycosyltransferases (GTs) that use an immense catalog of activated sugar donors to build the repeating unit and modifying enzymes that add further heterogeneity. Classical Leloir GTs incorporate α- or β-linked sugars by inverting or retaining mechanisms, depending on the nucleotide sugar donor. In contrast, the mechanism of known ribofuranosyltransferases is confined to β-linkages, so the existence of α-linked ribofuranose in some glycans dictates an alternative strategy. Here, we use
Citrobacter youngae
O1 and O2 lipopolysaccharide O antigens as prototypes to describe a widespread, versatile pathway for incorporating side-chain α-linked pentofuranoses by extracytoplasmic postpolymerization glycosylation. The pathway requires a polyprenyl phosphoribose synthase to generate a lipid-linked donor, a MATE-family flippase to transport the donor to the periplasm, and a GT-C type GT (founding the GT136 family) that performs the final glycosylation reaction. The characterized system shares similarities, but also fundamental differences, with both cell wall arabinan biosynthesis in mycobacteria, and periplasmic glucosylation of O antigens first discovered in
Salmonella
and
Shigella
. The participation of auxiliary epimerases allows the diversification of incorporated pentofuranoses. The results offer insight into a broad concept in microbial glycobiology and provide prototype systems and bioinformatic guides that facilitate discovery of further examples from diverse species, some in currently unknown glycans.
A step-by-step guide to fragmenting bundled actin filaments
Authors: Kadzik Rachel S. , Kovar David R.
Published: May 2024

There has long been conflicting evidence as to how bundled actin filaments, found in cellular structures such as filopodia, are disassembled. In this issue, Chikireddy et al. (https://doi.org/10.1083/jcb.202312106) provide a detailed in vitro analysis of the steps involved in fragmentation of fascin-bundled actin filaments and propose a novel mechanism for severing two-filament bundles.
Observation of Giant Topological Hall Effect in Room-Temperature Ferromagnet Cr0.82Te
Authors: Miao 苗 Wei-Ting 伟婷 , Zhen 甄 Wei-Li 伟立 , Lu 陆 Zhen 振 , Wang 王 Heng-Ning 恒宁 , Wang 王 Jie 杰 , Niu 牛 Qun 群 , Tian 田 Ming-Liang 明亮
Published: May 2024

Novel magnetic materials with non-trivial magnetic structures have led to exotic magnetic transport properties and significantly promoted the development of spintronics in recent years. Among them is the Cr
x
Te
y
family, the magnetism of which can persist above room temperature, thus providing an ideal system for potential spintronic applications. Here we report the synthesis of a new compound, Cr0.82Te, which demonstrates a record-high topological Hall effect at room temperature in this family. Cr0.82Te displays soft ferromagnetism below the Curie temperature of 340 K. The magnetic measurement shows an obvious magneto-crystalline anisotropy with the easy axis located in the ab plane. The anomalous Hall effect can be well explained by a dominating skew scattering mechanism. Intriguing, after removing the normal Hall effect and anomalous Hall effect, a topological Hall effect can be observed up to 300 K and reaches up to 1.14 μΩ⋅cm at 10 K, which is superior to most topological magnetic structural materials. This giant topological Hall effect possibly originates from the noncoplanar spin configuration during the spin flop process. Our work extends a new Cr
x
Te
y
system with topological non-trivial magnetic structure and broad prospects for spintronics applications in the future.
Ameliorated in vitro anti-cancer efficacy of methotrexate loaded zinc oxide nanoparticles in breast cancer cell lines MCF-7 & MDA-MB-231 and its acute toxicity study
Authors: Joshi Mitesh , Bhatt Purvi
Published: May 2024

Traditional therapies often struggle with specificity and resistance in case of cancer treatments. It is therefore important to investigate new approaches for cancer treatment based on nanotechnology. Zinc oxide nanoparticles (ZnONPs) are known to exhibit anti-cancer properties by inducing oxidative stress, apoptosis, and cell cycle arrest. Methotrexate (MTX) a known anti-folate shows specificity to folate receptors and interrupts healthy functioning of cells. This study proposes the use of previously characterized biocompatible Methotrexate loaded Zinc oxide nanoparticles (MTX-ZnONPs) as a dual action therapeutic strategy against breast cancer cell lines, MCF-7 (MTX-sensitive) and MDA-MB-231 (MTX-resistant). To elucidate the cytotoxicity mechanism of MTX-ZnONPs an in depth In vitro study was carried out. In vitro assays, including cell cycle analysis, apoptosis assay, and western blot analysis to study the protein expression were performed. Results of these assays, further supported the anti-cancer activity of MTX-ZnONPs showing apoptotic and necrotic activity in MCF-7 and MDA-MB-231 cell line respectively. In vivo acute oral toxicity study to identify the LD50 in animals revealed no signs of toxicity and mortality up to 550 mg kg−1 body weight of animal, significantly higher LD50 values than anticipated therapeutic levels and safety of the synthesized nanosystem. The study concludes that MTX-ZnONPs exhibit anti-cancer potential against breast cancer cells offering a promising strategy for overcoming resistance.
Quantitative validation of the suprasternal pressure signal to assess respiratory effort during sleep
Authors: Cerina Luca , Papini Gabriele B , Fonseca Pedro , Overeem Sebastiaan , van Dijk Johannes P , van Meulen Fokke , Vullings Rik
Published: May 2024

Objective. Intra-esophageal pressure (Pes) measurement is the recommended gold standard to quantify respiratory effort during sleep, but used to limited extent in clinical practice due to multiple practical drawbacks. Respiratory inductance plethysmography belts (RIP) in conjunction with oronasal airflow are the accepted substitute in polysomnographic systems (PSG) thanks to a better usability, although they are partial views on tidal volume and flow rather than true respiratory effort and are often used without calibration. In their place, the pressure variations measured non-invasively at the suprasternal notch (SSP) may provide a better measure of effort. However, this type of sensor has been validated only for respiratory events in the context of obstructive sleep apnea syndrome (OSA). We aim to provide an extensive verification of the suprasternal pressure signal against RIP belts and Pes, covering both normal breathing and respiratory events. Approach. We simultaneously acquired suprasternal (207) and esophageal pressure (20) signals along with RIP belts during a clinical PSG of 207 participants. In each signal, we detected breaths with a custom algorithm, and evaluated the SSP in terms of detection quality, breathing rate estimation, and similarity of breathing patterns against RIP and Pes. Additionally, we examined how the SSP signal may diverge from RIP and Pes in presence of respiratory events scored by a sleep technician. Main results. The SSP signal proved to be a reliable substitute for both esophageal pressure (Pes) and respiratory inductance plethysmography (RIP) in terms of breath detection, with sensitivity and positive predictive value exceeding 75%, and low error in breathing rate estimation. The SSP was also consistent with Pes (correlation of 0.72, similarity 80.8%) in patterns of increasing pressure amplitude that are common in OSA. Significance. This work provides a quantitative analysis of suprasternal pressure sensors for respiratory effort measurements.
Study on copper-to-copper bonding of three-dimensional integrated circuits using the quasicontinuum method
Authors: Nguyen Hoang-Giang , Wu Miao-Jing , Fang Te-Hua
Published: May 2024

Cu-Cu bonding presents an attractive approach to bottom-up manufacturing, facilitating nanoparticle production, linking, and restoration. The ramifications of varying bonding depths and orientations exhibit distinct characteristics. At the same time, investigations into the material composition of nanoscale bonded pairs involve scrutiny of atomic slippage, strain distribution, and the force-displacement profile. The methodology simulates the Cu-Cu bonding process by implementing the quasi-continuum (QC) approach, constituting a multifaceted mixed molecular dynamics technique integrating atomistic and continuum methods. The analysis of results reveals variations in the Contact effect induced by the four orientations, along with discrepancies in the atomic slippage observed in distinct directions. Notably, a pronounced distinction is discernible in the directional movement. Specifically, the strained regions on the flat surface of the lower substrate, characterized by the directionality of X[001]-Y[110], exhibit a notably broader range of atomic slip compared to regions strained by alternative orientations. Furthermore, the directional alignment of X[110]-Y[111] illustrates that irrespective of whether the lower substrate’s surface is flat or rough, the orientation of atomic slip diverges. In conclusion, our study employed a quasi-continuous method to explore the bonding efficacy of copper-to-copper interfaces on flat and irregular substrate surfaces. Through this approach, we scrutinized the distributions of strain, stress, average Newtonian force, and atom differential arrangement direction across different orientations.
Exploring the structural, morphological, and multiferroic properties of Al3+ modified (1-x) BCZT-(x) CFO ceramic composites
Authors: Hussain Shahzad , Dilpazir Hira , Naveed-Ul-Haq M , Waseem Muhammad , Ali Tahir
Published: May 2024

Multiferroics with strong magnetoelectric coupling can be created by improving the magnetostriction of the ferrite phase and combining it with the best-known piezoelectric. Herein, the ferromagnetic CoFe2O4 was modified with Al incorporation further improve the resistivity, magnetic, and magnetostrictive properties and then combined with (0.5)Ba(Zr0.2Ti0.8)O3−(0.5)(Ba0.7Ca0.3)TiO3 (BCZT) with different weight percentages. XRD results revealed the presence of a mixed spinel cubic phase for CAF (Fd-3m), whereas BCZT crystallized in a tetragonal structure (Amm2) in composite systems. The dielectric response of the materials was studied using impedance spectroscopy and it displayed a typical Maxwell–Wagner polarization of two-phase composites. The magnetic response of the CAF sample improved significantly which is attributed to the preference of Al3+ ions on tetrahedral sites. The magnetization of composites increased as the nonmagnetic BCZT component increased and the (0.75)CAF-(0.25)BCZT system had the highest saturation magnetization. We anticipate that these systems will have significantly improved magnetoelectric characteristics than unmodified CFO-BCZT systems.
Unveiling multi-wave patterns: dynamic characterization and sensitivity analysis of the Yu-Toda-Sasa-Fukuyama model in lattice and liquid
Authors: Riaz Muhammad Bilal , Kazmi Syeda Sarwat , Jhangeer Adil
Published: May 2024

In this study, an examination of the Yu-Toda-Sasa-Fukuyama equation is undertaken, a model that characterizes elastic waves in a lattice or interfacial waves in a two layer liquid. Our emphasis lies in conducting a comprehensive analysis of this equation through various viewpoints, including the examination of soliton dynamics, exploration of bifurcation patterns, investigation of chaotic phenomena, and a thorough evaluation of the model’s sensitivity. Utilizing a simplified version of Hirota’s approach, multi-soliton pattens, including 1-wave, 2-wave, and 3-wave solitons, are successfully derived. The identified solutions are depicted visually via 3D, 2D, and contour plots using Mathematica software. The dynamic behavior of the discussed equation is explored through the theory of bifurcation and chaos, with phase diagrams of bifurcation observed at the fixed points of a planar system. Introducing a perturbed force to the dynamical system, periodic, quasi-periodic and chaotic patterns are identified using the RK4 method. The chaotic nature of perturbed system is discussed through Lyapunov exponent analysis. Sensitivity and multistability analysis are conducted, considering various initial conditions. The results acquired emphasize the efficacy of the methodologies used in evaluating solitons and phase plots across a broader spectrum of nonlinear models.
Natural convection and heat transmission of two-phase Bingham Fe3O4-CoFe2O4-water hybrid nanofluid flow in an enclosure with a corrugated heated cylinder
Authors: Mahmud Muhammad Zawad , Molla Md Mamun
Published: May 2024

The Galerkin weighted residual finite element method (GFEM) has been used to numerically investigate the natural convection flow of two-phase Bingham hybrid nanofluid in a square cavity with a corrugated cylinder at the center. The base fluid here is water. The hybrid nanofluid is made of Fe3O4-CoFe2O4 nanoparticles. The flow inside the enclosure is considered laminar, non-Newtonian, and incompressible. The corrugated cylinder is taken heated. The top and bottom walls of the outer square are considered adiabatic, and the left and right walls are considered cold. Several non-dimensional parameters, including the Rayleigh number (Ra = 104, 105, 106), the Bingham number (Bn = 0, 0.5, 1), the volume fraction (ϕ = 0.00, 0.04), the Brownian parameter (Nb = 0.1, 0.2, 0.3), thermophoresis parameter (Nt = 0.1, 0.2, 0.3), buoyancy ratio (Nr = 0.1, 0.2, 0.3), corrugation (N = 5, 6, 7), the Prandtl number (Pr = 6.2), and the Lewis number (Le = 1000) have been numerically simulated. The main focus of this work is to witness streamlines, isotherm, and nanoparticles’ volume fraction distribution and understand heat transmission with the help of average Nusselt number and local Nusselt number for several parameters for a two-phase Bingham hybrid nanofluid. The results show that an upsurge in Ra increases the extent of the upper two vortices and decreases the extent of the lower two vortices. All four vortices are seen to increase in dimension for an increase in Bn. The same observation is found for an increase in ϕ. The lower vortices are growing, and the top ones are nearly eliminated for base fluid, while those are visible for nanofluid when corrugation is increased. A further expansion completely destroyed the higher ones and increased the size of the bottom ones. The average Nusselt number (

Nu

¯

) increases when Ra is incremented.

Nu

¯

rises with a rise in ϕ. An increment in ϕ to 0.04 results in a 4.43% gain in

Nu

¯

. An increase in Bn is causing

Nu

¯

to drop by 18.02%. For Ra = 105 and Bn = 2, ϕ = 0.02 has the maximum heat transfer enhancement between 0.00 ≤ ϕ ≤ 0.04. In the future, we plan to use mixed convection in a three-dimensional domain along with the impact of magnetohydrodynamics (MHD).
A modified Astable multi-vibrator-driven 3D chaotic circuit with Dual LC band stop filters
Authors: Ponnambalam Maran , Ponnambalam Mathivanan
Published: May 2024

This work describes a proposed circuit design with three essential parts: an Astable Multi-vibrator (ASMV) source producing a square wave as the driving signal, a two-stage LC band stop filter selectively attenuating frequencies with a focus on suppressing high-frequency components, and an integrator combining outputs from the second and third stages. Using two extra feedback channels, a standard ASMV gains the ability to change the duty cycle of the square wave, effectively altering the amplitude and duty cycle of the ASMV output signal. The LC band stop filter is vital for reducing or blocking frequencies close to 650 Hz and allowing other frequencies to predominate in the signal. The output frequency of the proposed circuit is governed by its specific parameters and frequency response characteristics. The suggested three-dimensional chaotic circuit produces dynamic, complex chaotic attractors with a simple circuit complexity. The differential equations describing the circuit’s functioning were checked using MATLAB. Circuit working was verified using Keysight ADS simulation and validated by experimental measurement. The randomness of the state variables are verified using the NIST test.
Search for heavy dark matter from dwarf spheroidal galaxies: leveraging cascades and subhalo models
Authors: Song Deheng , Hiroshima Nagisa , Murase Kohta
Published: May 2024

The Fermi Large Area Telescope (Fermi-LAT) has been widely used to search for
Weakly Interacting Massive Particle (WIMP) dark matter signals due to its unparalleled sensitivity
in the GeV energy band. The leading constraints for WIMP by Fermi-LAT are obtained from the
analyses of dwarf spheroidal galaxies within the Local Group, which are compelling targets for
dark matter searches due to their relatively low astrophysical backgrounds and high dark matter
content. In the meantime, the search for heavy dark matter with masses above TeV remains a
compelling and relatively unexplored frontier. In this study, we utilize 14-year Fermi-LAT
data to search for dark matter annihilation and decay signals in 8 classical dwarf spheroidal
galaxies within the Local Group. We consider secondary emission caused by electromagnetic cascades
of prompt gamma rays and electrons/positrons from dark matter, which enables us to extend the
search with Fermi-LAT to heavier dark matter cases. We also update the dark matter subhalo
model with informative priors respecting the fact that they reside in subhalos of our Milky Way
halo aiming to enhance the robustness of our results. We place constraints on dark matter
annihilation cross section and decay lifetime for dark matter masses ranging from 103 GeV to
1011 GeV, where our limits are more stringent than those obtained by many other high-energy
gamma-ray instruments.
Direct Detection and Characterization of Exoplanets Using Imaging Fourier Transform Spectroscopy
Authors: Zhang 张 Jingwen 婧雯 , Bottom Michael , Serabyn Eugene
Published: May 2024

Space-based direct imaging provides prospects for detection and spectral characterization of exoplanets at optical and near-infrared wavelengths. Integral field spectrographs (IFS) have been historically baselined for these mission concepts. However, multiple studies have revealed that detector noise is a serious obstacle for such instruments when observing extremely faint targets such as Earth-like planets. Imaging Fourier transform spectrographs (iFTS) are generally less sensitive to detector noise, and have several other compelling features such as simultaneous imaging and spectroscopy, smaller-format detector requirements, and variable spectral resolving power. To date, they have not been studied as options for such missions. Here, we compare the capabilities of IFS and iFTS for directly obtaining spectra from an Earth-like planet using both analytic and numerical models. Specifically, we compare the required exposure times to achieve the same signal-to-noise ratio with the two architectures over a range of detector and optical system parameters. We find that for a 6 m telescope, an IFS outperforms an iFTS at optical wavelengths due to the effects of distributed photon noise. In the near-IR, the relative efficiency of an IFS and iFTS depends critically on the instrument design and detector noise. An iFTS will be more efficient than an IFS if the readout noise of the near-IR detector is above ∼2–3 e− pix−1 frame−1 (t
frm = 1000 s), which correspond to half to one-third of the state-of-art detector noise. However, if the readout noise is reduced below this threshold, the performance of an IFS will experience a substantial improvement and become more efficient. These results motivate consideration of an iFTS as an alternative option for future direct imaging space missions in the near-IR.
Developing a penning ionization gauge ion source with a filament for a compact ion microbeam system
Authors: Ishii Yasuyuki , Ohkubo Takeru , Saito Yuichi
Published: May 2024

We present the development of a penning ionization gauge ion source with a filament (F-PIG) for producing submicron ion beams in a compact ion microbeam system. The conventional penning ionization gauge ion source (PIG) represents a viable choice for microbeam system due to its compact size and low power consumption. However, directly utilizing a PIG for generating submicron ion beam poses challenges, primarily from significant energy spread, causing substantial aberrations. Considering this, this study proposes a solving the generation of low-voltage discharge plasma, achieved using low-energy electrons from a filament by focusing on the development of F-PIG for this purpose. Experimental results demonstrate that the F-PIG exhibits considerable promise an ion source to forming submicron beam within a compact ion microbeams system. These findings indicate that F-PIG can effectively reduce the width of the beam energy spread, making it a valuable asset for microbeam applications.