bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental and theoretical investigations of the radiation-induced conductivity in spacecraft polymers at extremely low temperatures
Authors: Tyutnev Andrey , Saenko Vladimir , Mullakhmetov Ilshat , Pozhidaev Evgenii
Published: September 2023

Radiation-induced conductivity (RIC) of polyethyleneterepfthalate and polypiromellitimide has been studied experimentally and numerically in a broad time range from some microseconds to seconds at 103 K. It has been established that the charge carrier transport is dispersive with a low value of the dispersion parameter α (0.08–0.12). We have suggested a direct method of determination of the frequency factor of the Rose–Fowler–Vaisberg (RFV) model, which has been parameterized using computer simulations by the trial-and-error method. The main concern is a critical analysis of the existing theories of geminate recombination. It has been shown that the traditional RFV model is well suited to describe the RIC in studied polymers even at 103 K if due corrections to the notion of a free charge carrier and a non-Langevin bimolecular recombination have been made. The problem of a space charge field due to beam electrons stopped in a polymer sample, which is especially important at low temperatures, has been accounted for but not fully explained.
Phononic Weyl pair, phononic Weyl complex, phononic real Chern insulator state, and phononic corner modes in 2D Kekulé-order graphene
Authors: Li Jianghua , Liu Ying , Bai Jingbo , Xie Chengwu , Yuan Hongkuan , Cheng Zhenxiang , Wang Wenhong , Wang Xiaotian , Zhang Gang
Published: September 2023

The conceptual framework of topological states has recently been extended to bosonic systems, particularly phononic systems. In this work, we chose the recently experimentally prepared two-dimensional (2D) Kekulé-order graphene as a target to propose the coexistence of gapless and gapped topological phonon states in its phonon curves. This is the first work to investigate rich gapped and gapless topological phonon states in experimentally feasible 2D materials. For the gapped topological phonons, 2D Kekulé-order graphene hosts phononic real Chern insulator states, i.e., second-order topological states, and corner vibrational modes inside frequency gaps at 27.96 and 37.065 THz. For the gapless topological phonons, 2D Kekulé-order graphene hosts a phononic Weyl pair [comprising two linear Weyl points (LWPs)] and a phononic Weyl complex [comprising one quadratic nodal point (QNP) and two LWPs] around 7.54 and 47.3 THz (39.2 THz), respectively. Moreover, the difference between the phononic Weyl pair and the phononic Weyl complex was investigated in detail. Our study not only promotes 2D Kekulé-order graphene as a concrete material platform for exploring the intriguing physics of phononic second-order topology but also proposes the coexistence of different categories of Weyl phonons, i.e., a Weyl complex that comprises two LWPs and one QNP, in two dimensions. Our work paves the way for new advancements in topological phononics comprising gapless and gapped topological phonons.
A self-locking structure for quantum dot DFB and FP lasers based on optical feedback
Authors: Yang Libo , Cao Sheng , Shi Junbing , Xue Xin , Wang Sheng Chao
Published: September 2023

This paper presents a self-coherent optical feedback system that achieves resonance between the external cavity mode and the relaxation oscillation frequency of distributed feedback (DFB) laser and the repetition frequency of Fabry–Perot (FP) laser, all in an effort to achieve optical feedback self-locking. Results using this system show that for FP lasers, feedback is able to reduce the 3 dB radio frequency linewidth from 2 MHz to 600 kHz. In the case of DFB lasers, an electric frequency comb with an external cavity repetition rate of 17.25 MHz is achieved. This research presents a significant step toward the improvement of the performance of quantum dot lasers in optical communication systems.
Clustering in gallium ion beam sputtered compound materials driven by bond strength and interstitial/vacancy reaction
Authors: Ma Zhenyu , Zhang Xin , Liu Pu , Deng Yong , Hu Wenyu , Chen Longqing , Zhu Jun , Chen Sen , Wang Zhengshang , Shi Yuechun , Ma Jian , Wang Xiaoyi , Qiu Yang , Zhang Kun , Cui Xudong , Walther Thomas
Published: September 2023

The investigation of chemical reactions during ion irradiation is a frontier for the study of the ion–material interaction. In order to probe the chemistry of ion produced nanoclusters, valence electron energy loss spectroscopy (VEELS) was exploited to investigate Ga+ ion damage in Al2O3, InP, and InGaAs, where each target material has been shown to react differently to the interaction between impinging ions, recoil atoms, and vacancies: metallic Ga, ternary InGaP clusters, and metallic In clusters are formed in Al2O3, InP, and InGaAs, respectively. Supporting simulations based on Monte Carlo and crystal orbital Hamiltonian calculations indicate that the chemical constitution of cascade induced nano-precipitates is a result of a competition between interstitial/vacancy consumption rates and preferential bond formation due to differing bond strengths.
Mechanism of a transverse jet mixing enhanced by high-frequency plasma energy deposition
Authors: Wang Hongyu , Yang Yanguang , Hu Weibo , Wang Gang , Xie Feng , Fan Xiaohua
Published: September 2023

The mixing mechanism of a transverse jet enhanced by high-frequency plasma energy deposition is investigated at Ma = 6.13 using both experimental measurements and improved delayed detached eddy simulation. The test configuration is a flat plate with argon gas injected vertically at its center. The plasma actuator driven by 20 and 50 kHz pulsed discharge is used as a mixing enhancement device, which is located upstream of the jet. The schlieren and planar laser scattering visualization show that the interaction between the hot bubbles induced by the plasma energy deposition and the bow shock caused by the jet generates large scale vortices that diffuse the jet components, and improve the penetration depth of the jet. These large-scale vortices augment the vorticity and turbulence intensity, thus enhancing the jet component mixing. The vortex analysis indicated that the jet vorticity increases due to the stronger baroclinic torque induced by Richtmyer–Meshkov (R–M) instability around the bubble/shock interaction region, which promotes the turbulent kinetic energy and the production of the large-scale vortex structures. The baroclinic torque and the resulting large-scale vortices are the physical origin of the enhanced mixing of the transverse jet.
Extraction and analysis of flow features in planar synthetic jets using different machine learning techniques
Authors: Muñoz Eva , Dave Himanshu , D'Alessio Giuseppe , Bontempi Gianluca , Parente Alessandro , Le Clainche Soledad
Published: September 2023

Synthetic jets are useful fluid devices with several industrial applications. In this study, we use the flow fields generated by two synchronously operating synthetic jets and simulated using direct numerical simulations. These flow fields are characterized by a jet Reynolds number, Re=100, 150, and 200, and a Strouhal number, St=0.03. We benchmark four different dimensionality reduction techniques: (1) higher-order dynamic mode decomposition (HODMD), (2) proper orthogonal decomposition, (3) vector quantization via principal component analysis (VQPCA), and (4) linear autoencoders. These techniques are often used in generating reduced-order models (ROMs). The performances of these techniques are compared (i) in terms of their ability to accurately reconstruct the high-dimensional flow fields from their low-dimensional manifolds and (ii) in terms of their ability to extract meaningful low-dimensional patterns/features/structures that best describe the main dynamics of the synthetic jets. The similarity between the extracted features is also quantitatively assessed with the help of Procrustes analysis, showing how manifolds from different techniques become more similar when a larger number of modes are retained. Accurate reconstruction and model complexity (or interpretability) are often two counter-balancing objectives. In this comparative study, we found that among the four techniques, VQPCA has clear advantages for developing accurate ROMs, while HODMD is useful for understanding the dynamics of synthetic jets, providing additional information that is not readily available with other methods.
Investigations on lock-in vortex-induced vibration of an airfoil at a high angle of attack based on detached eddy simulation
Authors: Lian Bo , Tong Xin , Zhu Xiaocheng , Du Zhaohui , Cui Yongdong , Khoo Boo Cheong
Published: September 2023

Large-scale modern wind turbines at standstill are prone to vortex-induced vibration (VIV). In this study, coupled fluid–solid dynamics of the wind turbine airfoil at a 90° attack angle are performed using the detached eddy simulation. The fully developed vibration responses with different structural dampings are explored in detail. The frequency lock-in regime is determined, and the corresponding phase differences between the lift and displacement are presented with the Lissajous curve. The dominant surface pressure mode and wake flow exhibit significant three-dimensional flow characteristics in unlock-in conditions, while a strong spanwise correlation in lock-in conditions is detected. The pressure fluctuation on the suction side in the lock-in state is observed to be more significant than in the unlock-in state. The effect of the distributed airfoil surface pressure on VIV is evaluated by considering the contribution value and the cyclic aerodynamic work density. With the decrease in structural damping, the aerodynamic work near the leading edge gets enhanced and the negative work region is reduced, leading to a higher amplitude of VIV. The beat vibration and hysteresis behavior at the critical reduced velocity are also analyzed in both the time domain and frequency domain.
Active reset of superconducting qubits using the electronics based on RF switches
Authors: Han Lian-Chen , Xu Yu , Lin Jin , Chen Fu-Sheng , Li Shao-Wei , Guo Cheng , Li Na , Li Dong-Dong , Li Yu-Huai , Gong Ming , Liao Sheng-Kai , Peng Cheng-Zhi
Published: September 2023

Active reset of qubits is a crucial step in achieving quantum algorithms, particularly in fault-tolerant quantum computing, as it allows qubits to be quickly initialized to the ground state. In this paper, we demonstrate active reset of superconducting qubits using the feedback electronics based on RF switches. We are able to reset the qubit to the ground state in 11.412 µs with a success rate of 99.82%, which is better than the natural relaxation method in terms of both time consumption (180 µs) and success rate (99.61%). The demonstrated method facilitates fast and high-fidelity qubit initialization, holding practical significance for large-scale quantum computation.
Improved electrical resistivity-temperature characteristics of oriented hBN composites for inhibiting temperature-dependence DC surface breakdown
Authors: Huang Zhengyong , Zhang Yingfan , Wang Haohuan , Li Jian
Published: September 2023

In this paper, oriented hBN composites with anisotropic thermal conductivity are employed to improve electrical resistivity-temperature characteristics, thus inhibiting the occurrence of DC surface flashover under the temperature gradient by directionally manipulating heat flow. The DC surface flashover performance, electrical resistivity, carrier mobility, and electric field distribution of composites depending on the hBN orientation are studied at different temperatures. When the angle between the hBN basal plane and the axis of the electrodes is 90°, the out-of-plane oriented hBN composite shows the best electrical resistivity-temperature characteristics than that of the polymer filled with ceramic particles of positive temperature coefficient, whose surface flashover voltage is 28% higher than that of the out-of-plane oriented hBN composite with the angle of 0° between the hBN basal plane and the axis of the electrodes under the high-voltage electrode heated at 160 °C. The least rise in carrier mobility and electric field intensity near the GND electrode is the main factor in inhibiting the occurrence of DC surface flashover of the oriented hBN composites at high temperatures. The work presented in this paper will notably influence future research directions and modification solutions for DC dielectric materials.
Thermocapillary convection in a laser-heated Ni melt pool: A molecular dynamics study
Authors: Politano O. , Baras F.
Published: September 2023

Thermocapillary convection was investigated in a metallic system of pure Ni, at the nanoscale, by molecular dynamics. The system interface was irradiated by a heat flux, mimicking a focused laser source. The melt pool was submitted to a large temperature gradient that modified the surface tension along the interface. In liquid metal, because surface tension typically decreases with increasing temperature, the result is a gradient of surface tension along the free surface. The liquid metal, therefore, started to flow in the direction of high surface tension. Two counter-rotating convection cells developed, characteristic of those observed in welding and other material processing. A systematic estimation of relevant parameters in hydrodynamics allowed us to interpret the results in terms of Prandtl, Marangoni, and Péclet numbers. This study demonstrates the influence of laser power and system size on pool shape and flow characteristics.
Enhancing ion transport in nanofluidic systems through counter-charged nanochannels
Authors: Zhou Le , Shi Dachuang , Lin Shiji , Zhou Yanguang , Li Zhigang
Published: September 2023

In this work, we propose a new strategy to enhance ion transport in nanofluidic systems using counter-charged nanochannels, where half of the channels are positively changed while the other half are negatively charged. Molecular dynamics simulations and experiments are conducted to demonstrate the idea. Simulations show that the ionic current for the proposed system can be 5.8 times higher than that in the traditional fluidic systems, i.e., uniformly charged systems. The enhancement is caused by the separate transport of cations and anions in negatively and positively charged channels, respectively, for which the effective energy barrier for the ion transport is low. Experiments are carried out to confirm the proposed method. The results in this work provide helpful information for the design of certain energy systems, such as batteries and electrodes.
Environmental fluctuations explain the universal decay of species-abundance correlations with phylogenetic distance
Authors: Sireci Matteo , Muñoz Miguel A. , Grilli Jacopo
Published: September 2023

Multiple ecological forces act together to shape the composition of microbial communities. Phyloecology approaches—which combine phylogenetic relationships between species with community ecology—have the potential to disentangle such forces but are often hard to connect with quantitative predictions from theoretical models. On the other hand, macroecology, which focuses on statistical patterns of abundance and diversity, provides natural connections with theoretical models but often neglects interspecific correlations and interactions. Here, we propose a unified framework combining both such approaches to analyze microbial communities. In particular, by using both cross-sectional and longitudinal metagenomic data for species abundances, we reveal the existence of an empirical macroecological law establishing that correlations in species-abundance fluctuations across communities decay from positive to null values as a function of phylogenetic dissimilarity in a consistent manner across ecologically distinct microbiomes. We formulate three variants of a mechanistic model—each relying on alternative ecological forces—that lead to radically different predictions. From these analyses, we conclude that the empirically observed macroecological pattern can be quantitatively explained as a result of shared population-independent fluctuating resources, i.e., environmental filtering and not as a consequence of, e.g., species competition. Finally, we show that the macroecological law is also valid for temporal data of a single community and that the properties of delayed temporal correlations can be reproduced as well by the model with environmental filtering.
Fatty acid elongation by ELOVL6 hampers remyelination by promoting inflammatory foam cell formation during demyelination
Authors: Garcia Corrales Aida V. , Verberk Sanne G. S. , Haidar Mansour , Grajchen Elien , Dehairs Jonas , Vanherle Sam , Loix Melanie , Weytjens Tine , Gervois Pascal , Matsuzaka Takashi , Lambrichts Ivo , Swinnen Johannes V. , Bogie Jeroen F. J. , Hendriks Jerome J. A.
Published: September 2023

A hallmark of multiple sclerosis (MS) is the formation of multiple focal demyelinating lesions within the central nervous system (CNS). These lesions mainly consist of phagocytes that play a key role in lesion progression and remyelination, and therefore represent a promising therapeutic target in MS. We recently showed that unsaturated fatty acids produced by stearoyl-CoA desaturase-1 induce inflammatory foam cell formation during demyelination. These fatty acids are elongated by the “elongation of very long chain fatty acids” proteins (ELOVLs), generating a series of functionally distinct lipids. Here, we show that the expression and activity of ELOVLs are altered in myelin-induced foam cells. Especially ELOVL6, an enzyme responsible for converting saturated and monounsaturated C16 fatty acids into C18 species, was found to be up-regulated in myelin phagocytosing phagocytes in vitro and in MS lesions. Depletion of
Elovl6
induced a repair-promoting phagocyte phenotype through activation of the S1P/PPARγ pathway.
Elovl6
-deficient foamy macrophages showed enhanced ABCA1-mediated lipid efflux, increased production of neurotrophic factors, and reduced expression of inflammatory mediators. Moreover, our data show that ELOVL6 hampers CNS repair, as
Elovl6
deficiency prevented demyelination and boosted remyelination in organotypic brain slice cultures and the mouse cuprizone model. These findings indicate that targeting ELOVL6 activity may be an effective strategy to stimulate CNS repair in MS and other neurodegenerative diseases.
Earthquake alerting based on spatial geodetic data by spatiotemporal information transformation learning
Authors: Tong Yuyan , Hong Renhao , Zhang Ze , Aihara Kazuyuki , Chen Pei , Liu Rui , Chen Luonan
Published: September 2023

Alerting for imminent earthquakes is particularly challenging due to the high nonlinearity and nonstationarity of geodynamical phenomena. In this study, based on spatiotemporal information (STI) transformation for high-dimensional real-time data, we developed a model-free framework, i.e., real-time spatiotemporal information transformation learning (RSIT), for extending the nonlinear and nonstationary time series. Specifically, by transforming high-dimensional information of the global navigation satellite system into one-dimensional dynamics via the STI strategy, RSIT efficiently utilizes two criteria of the transformed one-dimensional dynamics, i.e., unpredictability and instability. Such two criteria contemporaneously signal a potential critical transition of the geodynamical system, thereby providing early-warning signals of possible upcoming earthquakes. RSIT explores both the spatial and temporal dynamics of real-world data on the basis of a solid theoretical background in nonlinear dynamics and delay-embedding theory. The effectiveness of RSIT was demonstrated on geodynamical data of recent earthquakes from a number of regions across at least 4 y and through further comparison with existing methods.
Mimicking superinfection exclusion disrupts alphavirus infection and transmission in the yellow fever mosquitoAedes aegypti
Authors: Reitmayer Christine M. , Levitt Emily , Basu Sanjay , Atkinson Barry , Fragkoudis Rennos , Merits Andres , Lumley Sarah , Larner Will , Diaz Adriana V. , Rooney Sara , Thomas Callum J. E. , von Wyschetzki Katharina , Rausalu Kai , Alphey Luke
Published: September 2023

Multiple viruses, including pathogenic viruses, bacteriophages, and even plant viruses, cause a phenomenon termed superinfection exclusion whereby a currently infected cell is resistant to secondary infection by the same or a closely related virus. In alphaviruses, this process is thought to be mediated, at least in part, by the viral protease (nsP2) which is responsible for processing the nonstructural polyproteins (P123 and P1234) into individual proteins (nsP1–nsP4), forming the viral replication complex. Taking a synthetic biology approach, we mimicked this naturally occurring phenomenon by generating a superinfection exclusion-like state inAedes aegyptimosquitoes, rendering them refractory to alphavirus infection. By artificially expressing Sindbis virus (SINV) and chikungunya virus (CHIKV) nsP2 in mosquito cells and transgenic mosquitoes, we demonstrated a reduction in both SINV and CHIKV viral replication rates in cells following viral infection as well as reduced infection prevalence, viral titers, and transmission potential in mosquitoes.
The earliest evidence of deep-sea vertebrates
Authors: Baucon Andrea , Ferretti Annalisa , Fioroni Chiara , Pandolfi Luca , Serpagli Enrico , Piccinini Armando , de Carvalho Carlos Neto , Cachão Mário , Linley Thomas , Muñiz Fernando , Belaústegui Zain , Jamieson Alan , Lo Russo Girolamo , Guerrini Filippo , Ferrando Sara , Priede Imants
Published: September 2023

Vertebrate macroevolution has been punctuated by fundamental habitat transitions from shallow marine origins to terrestrial, freshwater, and aerial environments. Invasion of the deep sea is a less well-known ecological shift because of low fossilization potential and continual loss of abyssal fossil record by ocean floor subduction. Therefore, there has been a lack of convincing evidence of bottom-living vertebrates from pre-Paleogene deep seas. Here, we describe trace fossils from abyssal plain turbidites of the Tethys Ocean, which, combined with nannofossil dating, indicate that fishes have occupied the deep seafloor since at least the Early Cretaceous (Hauterivian–Barremian). These structures are identical to those produced by modern demersal fishes that feed by either scratching the substrate or expose their prey by water flow generated by suction or jetting. The trace fossils suggest activity of at least three fish species exploiting a productive abyssal invertebrate sediment fauna. These observations are consistent with Early Cretaceous vertebrate transition to the deep sea triggered by the availability of new food sources. Our results anticipate the appearance of deep-seafloor fishes in the fossil record by over 80 My while reassessing the mode of vertebrate colonization of the deep sea.
Chloroplast import motor subunits FtsHi1 and FtsHi2 are located on opposite sides of the inner envelope membrane
Authors: Chang Chia-Yun , Chen Lih-Jen , Li Hsou-min
Published: September 2023

Protein import into chloroplasts is powered by ATP hydrolysis in the stroma. Establishing the identity and functional mechanism of the stromal ATPase motor that drives import is critical for understanding chloroplast biogenesis. Recently, a complex consisting of Ycf2, FtsHi1, FtsHi2, FtsHi4, FtsHi5, FtsH12, and malate dehydrogenase was shown to be important for chloroplast protein import, and it has been proposed to act as the motor driving protein translocation across the chloroplast envelope into the stroma. To gain further mechanistic understanding of how the motor functions, we performed membrane association and topology analyses on two of its subunits, FtsHi1 and FtsHi2. We isolated cDNA clones encoding FtsHi1 and FtsHi2 preproteins to perform in vitro import experiments in order to determine the exact size of each mature protein. We also generated antibodies against the C-termini of the proteins, i.e., where their ATPase domains reside. Protease treatments and alkaline and high-salt extractions of chloroplasts with imported and endogenous proteins revealed that FtsHi1 is an integral membrane protein with its C-terminal portion located in the intermembrane space of the envelope, not the stroma, whereas FtsHi2 is a soluble protein in the stroma. We further complemented an
FtsHi1
-knockout mutant with a C-terminally tagged FtsHi1 and obtained identical results for topological analyses. Our data indicate that the model of a single membrane–anchored pulling motor at the stromal side of the inner membrane needs to be revised and suggest that the Ycf2–FtsHi complex may have additional functions.
Correcting misperceptions of the other political party does not robustly reduce support for undemocratic practices or partisan violence
Authors: Druckman James N.
Published: September 2023

A growing consensus suggests that a cause of support for undemocratic practices and partisan violence is that partisans misperceive the other side. That is, they vastly exaggerate the extent to which members of the other party support undemocratic practices and violence. When these misperceptions are corrected, citizens’ own beliefs moderate. I present results from an experiment that show that misperception corrections do not have an effect in the presence of competing information (i.e., that challenges the validity of the correction or offers a conflicting narrative). Basic corrections do not constitute a robust way to counter democratic backsliding stemming from citizens’ misperceptions. The results highlight the need to devise stronger misperception interventions and, more generally, to consider competing information environments when devising any scalable behavioral intervention.
Disenchantment of the word in sixteenth-century Dutch farce
Authors: Kramer Femke
Published: September 2023

Representations of exorcism in farces written and performed in the sixteenth-century Low Countries at first sight merely testify to their authors’ propensity for the grotesque and critical stance towards Roman Catholic rituals. This paper argues that these farcical exorcism episodes, besides ridiculing exorcism and expressing scepticism in matters of demonology, also undermined beliefs concerning the potency of language. Analysis of the ritual as represented in farce and the metadiscursive comments surrounding it points to a conception of the ceremony as “administering” inherently powerful words to an object. This conception is also reflected in a contemporaneous “speech act theory”avant la lettrewhich attributes autonomous powers to words. Viewed against a backdrop of historical and ethnographic documentation on this type of discourse, this notion is likely to be an outgrowth of perceptions underlying ritual discourse activities cross-culturally. Discrediting the belief that words are capable of affecting reality autonomously, the playwrights may have advocated an understanding of language as a fully man-made instrument, the use and efficacy of which are entirely human-controlled processes.
Insights into crystallographic and topographic characteristics of local corrosion attack on zinc
Authors: Zhong Xiangli , Withers Philip J. , Guo Yi , Zhou Xiaorong , Cole Ivan S.
Published: September 2023

Through large area crystallographic analysis across the whole cross-section of a 0.5 mm zinc wire by backscattered electron diffraction (EBSD) excavated by plasma focused ion beam (pFIB) and topographic analysis by scanning electron microscopy (SEM), the crystallographic and topographic characteristics of corrosion on zinc are identified and correlated. Striated domains dominating the surface are the result of preferential dissolution of non-basal planes leaving (0001) plates intersecting the surface. Remnant fragments of zinc lie close to the original surface which is due to the combined effects of the initial protective film on the surface and the crystallographic corrosion. Three corrosion layers were found, namely from the outside inwards, a highly porous outer layer, a densified intermediate layer and an attacked layer.
Excellent spin filtering and significant magnetoresistance of rhenium phthalocyanine molecular junctions on Au(100)
Authors: Hou Zhi-Yu , Yu Jing-Xin , Yin Shao-Chong , Liu Xiu-Ying , Li Xiao-Dong
Published: September 2023

Spin transport properties of single rhenium phthalocyanine (RePc) and double-rhenium phthalocyanine (Re2Pc2) molecular devices with gold electrodes have been investigated by combining Density Functional theory and nonequilibrium Green’s functions. It was found that the RePc molecular devices exhibited good spin filtration efficiency in the small bias range even in the absence of magnetic electrodes. The Re2Pc2 molecular device exhibited a large magnetoresistance and excellent spin-filtering properties at a finite bias, which can only be achieved by altering the magnetization orientation of the rhenium atom at the center of the phthalocyanine molecule. These conclusions of the rhenium phthalocyanine molecule may have potential application in magnetoresistive devices and spin filters.
Effect of CF4 concentration on the discharge dynamics and reactive species distribution of atmospheric nanosecond pulsed He plasma jet
Authors: Zhao Huan , Wang Lijun , Liu Jie
Published: September 2023

Based on a two dimensional self-consistent model, the effect of different CF4 concentrations on the discharge dynamics characteristics, F-containing species distribution and the distribution of the axial and radial ionization rates of He atmospheric pressure plasma jet (APPJ) has been investigated. In addition, the accuracy of the simulation is verified by comparing the experimental results. The ionization rate of He APPJ enhances with the increase of CF4 from 0% to 2% because of the Penning ionization of CF4 with metastable He while decreases in the case of 3% CF4 owing to the electronegativity and the electron excitation energy loss of CF4. The increase of CF4 concentration and the decrease of the electron density leads to the decrease of CF4
+ density at 3% CF4. CF3
+ density is determined by the Penning ionization rate of CF4 and the reaction rate of He+ + CF4 → CF3
+ + F + He. As CF4 concentration increases from 2% to 3%, the decrease of metastable He and He+ concentration results in the significant decrease of CF3
+ density. The densities of CF3
− and F− keep increasing from 1% to 3% CF4 due to the effect of the electron attachment reaction of CF4. With the addition of CF4, the ionization reaction of CF4 is gradually playing the major role in the streamer head, the Penning ionization of CF4 is the main source of electron ionization inside the jet and dominates in the formation of ionization wave tail. As the concentration of CF4 increases from 0% to 2%, the electron impact ionization rates of He and CF4 near the axis increase, resulting in the more uniform radial ionization rate distribution of He + 2% CF4 APPJ.
Large-scale and stacked transfer of bilayers MoS2 devices on a flexible polyimide substrate
Authors: Guo Xiaojiao , Wang Die , Zhang Dejian , Ma Jingyi , Wang Xinyu , Chen Xinyu , Tong Ling , Zhang Xinzhi , Zhu Junqiang , Yang Peng , Gou Saifei , Yue Xiaofei , Sheng Chuming , Xu Zihan , An Zhenghua , Qiu Zhijun , Cong Chunxiao , Zhou Peng , Fang Zhiqiang , Bao Wenzhong
Published: September 2023

Two-dimensional transition metal dichalcogenides (TMDs), as flexible and stretchable materials, have attracted considerable attention in the field of novel flexible electronics due to their excellent mechanical, optical, and electronic properties. Among the various TMD materials, atomically thin MoS2 has become the most widely used material due to its advantageous properties, such as its adjustable bandgap, excellent performance, and ease of preparation. In this work, we demonstrated the practicality of a stacked wafer-scale two-layer MoS2 film obtained by transferring multiple single-layer films grown using chemical vapor deposition. The MoS2 field-effect transistor cell had a top-gated device structure with a (PI) film as the substrate, which exhibited a high on/off ratio (108), large average mobility (∼8.56 cm2 V−1 s−1), and exceptional uniformity. Furthermore, a range of flexible integrated logic devices, including inverters, NOR gates, and NAND gates, were successfully implemented via traditional lithography. These results highlight the immense potential of TMD materials, particularly MoS2, in enabling advanced flexible electronic and optoelectronic devices, which pave the way for transformative applications in future-generation electronics.
Enhanced photocatalytic degradation of crystal violet dye and high-performance electrochemical supercapacitor applications of hydrothermally synthesised magnetic bifunctional nanocomposite (Fe3O4/ZnO)
Authors: Bhat Aabid Hussain , Chopan Nisar Ahmad , Chisti Hamida-Tun-Nisa
Published: September 2023

The present investigation employed a facile hydrothermal approach for the fabrication of Fe3O4/ZnO dual-functional magnetic nanocomposite. Supercapacitor and visible-light-driven photocatalytic applications of the material were explored. X-ray diffraction, Fourier transform infrared spectra, ultraviolet–visible diffuse reflectance spectra (UV–vis/DRS), field emission scanning electron microscopy (FE-SEM), energy dispersive x-ray spectroscopy, and vibrating sample magnetometer were used to analyse the nanocomposite’s structural, morphological, optical, and magnetic properties. The FE-SEM analysis demonstrated that the surface morphology of Fe3O4, ZnO, and the Fe3O4/ZnO nanocomposite consisted of nanoparticles, nanoflakes, and nanoparticles adhered to the nanoflakes, respectively. The maximum specific capacitance of the electrode based on the Fe3O4/ZnO nanocomposite was measured to be 736.36 Fg−1 at a scan rate of 5 mVs−1. The electrode also demonstrated remarkable cycling stability, retaining 86.5% of its capacitance even after 3000 cycles. The Fe3O4/ZnO nanocomposite was found to have an optical bandgap of 2.7 eV, an average particle size of 22.5 nm, and a saturation magnetization of 68.7 emu g−1. The photocatalysis experiment was conducted using the optimised settings, which included a pH of 7.0, a dye concentration of 30 mg l−1, a catalyst dose of 1 g l−1, and a contact time of 120 min. The Fe3O4/ZnO nanocomposite exhibited a notable degradation efficiency towards crystal violet dye upon exposure to visible light, achieving a degradation efficiency of 96.9%. This performance surpassed that of pure ZnO, which attained a degradation efficiency of 70.2%. The nanocomposite exhibited a rate constant of 2.80 × 10−2 min−1, which was found to be notably higher than that of pure ZnO (0.8 × 10−2 min−1), as determined through modelling (pseudo-first order linear fit). The radical scavenger experiments indicated that the superoxide radicals and hydroxyl radicals are the primary reactive species. The Fe3O4/ZnO photocatalyst can be effectively isolated using a bar magnet. Remarkably, the photocatalytic efficiency of the material remained almost entirely intact even after undergoing four cycles of recycling. In addition, this research opens up exciting new possibilities for use in fields like energy storage and pollution control.
Improving the electrical properties of transparent ZnO-based thin- film transistors using MgO gate dielectric with various oxygen concentrations
Authors: Hwang Jun-Dar , Hsu Zhu-Rong
Published: September 2023

Zinc oxide (ZnO)-based thin-film transistors (TFTs) have attracted increasing attention towards flat-panel displays as alternatives to silicon-based TFTs due to their transparency to visible light. Magnesium oxide (MgO) has a wide bandgap (7.8 eV) and high dielectric constant (k). This leads to the development of TFTs using MgO as a gate oxide layer, which can significantly reduce the operating voltage. However, the electrical properties and dielectric constant of MgO are determined from the percentage of oxygen in MgO. In this study, a MgO gate-oxide was deposited on ZnO by magnetron sputtering at various oxygen concentrations (0%, 66%, and 100%) to fabricate TFTs. With an increase in the oxygen concentration, the oxygen vacancies of MgO were compensated, thereby improving the crystallinity and enhancing the dielectric constant from 6.53 to 12.9 for the oxygen concentrations of 0% and 100%. No pinch-off (saturation) behavior was observed in the TFTs with 0% oxygen; however, the pinch-off voltages were significantly reduced to 17 and 2 V in the TFTs with 66% and 100% oxygen, respectively; hence, the TFT-100 could be operated at a low operating voltage (2 V). With an increase in oxygen from 0% to 100%, the threshold voltage and trap-state density significantly decreased from −159 V and 1.6 × 1018 cm−3 to −31.4 V and 6.5 × 1016 cm−3, respectively. The TFTs with 0% oxygen exhibited a higher field-effect mobility of 12 cm2 V−1 s−1 due to the uncompensated oxygen vacancy in ZnO, which had a higher electron concentration. After introducing oxygen atoms, the field-effect mobility decreased to 0.16 cm2 V−1 s−1 in the TFTs with 66% oxygen, which can be attributed to the compensated oxygen vacancy and lower electron concentration. In contrast, the field-effect mobility increased to 1.88 cm2 V−1 s−1 for the TFTs with 100% oxygen due to the enhanced dielectric constant and crystallinity of MgO.
Monitoring structural transformations in metamagnetic shape memory alloys by non-contact GMI technology
Authors: Beato-López Juan Jesús , La Roca Paulo , Algueta-Miguel José María , Garaio Eneko , Sánchez-Alarcos Vicente , Recarte Vicente , Gómez-Polo Cristina , Pérez-Landazábal José Ignacio
Published: September 2023

Different applications based on metamagnetic shape memory alloy (MSMA) require monitoring the evolution of the martensitic transformation (MT) to optimize the actuation mechanism. To avoid interaction with the active material, a non-contact technique would be ideal. Nevertheless, non-contact detection involves complex methods like diffraction, optical analysis, or electromagnetic technology. The present work demonstrates that the MT can be monitored without interaction with the active material using a low-cost technology based on the Giant Magnetoimpedance (GMI) effect. The GMI sensor is based on a (CoFe)SiB soft magnetic wire submitted to an alternating current and whose second harmonic voltage variation allows to detect changes in the strength of the stray magnetic fields linked to the metamagnetic phase transition. The sensor has been tested using the MT of a NiMnInCo MSMA. A specific application for environmental temperature control using the non-contact GMI sensor is proposed.
Optical sorting by trajectory tracking with high sensitivity near the exceptional points
Authors: Cui LiYong , Liu Song , Wang Neng
Published: September 2023

Exceptional points (EPs) in non-Hermitian systems embody abundant new physics and trigger various novel applications. In the optical force system, the motion of a particle near its equilibrium position is determined by the optical force stiffness matrix (OFSM), which is inherently non-Hermitian when the particle is illuminated by vortex beams. In this study, by exploiting the rapid variations in eigenvalues and the characteristics of particle motion near EPs of the OFSM, we propose a method to sort particles with subtle differences in their radii or refractive indices based on their trajectories in air. We demonstrate that the trajectory of a particle with parameters slightly larger than those corresponding to certain EPs closely resembles an ellipse. The increase in the major axis of the ellipse can be several orders of magnitude larger than the increase in particle radius. Furthermore, even a slight change in the refractive index can not only significantly alter the size of the ellipse but also rotate its orientation angle. Hence, particles with subtle differences can be distinguished by observing the significant disparities in their trajectories. This approach holds promise as a technique for the precise separation of micro and nanoscale particles.
Generalized
∂¯
-dressing method for coupled nonlocal NLS equation
Authors: Tian Meijie , Huang Yehui , Yao Yuqin , Wang Xiaoying
Published: September 2023

In this paper, we investigate a general integrable coupled nonlocal nonlinear Schrödinger (cnNLS) equation with reverse space and reverse time. First, we introduce a 4-component nonlocal nonlinear Schrödinger (nNLS) equation. Based on two 3 × 3 matrices

∂

¯

-problems, we obtain the N-soliton solutions of the 4-component nNLS equation by constructing two spectral transformation matrices R and

R

ˆ

with some specific scattering data

{

k

i

,

α

i

,

β

i

}

i
=
1

N

and

{

λ

j

,

ξ

j

,

η

j

}

j
=
1

N

˜

. We have the symmetry condition for R and

R

ˆ

. We express the determinant in the N-soliton solution in the form of sums with the help of Cauchy matrix properties to facilitate follow-up reduction. The general nonlocal reduction of the 4-component nNLS equation to the cnNLS equation is discussed in detail. After obtaining the 1-soliton solution of cnNLS equation, we analyse the nonsingular region of the single soliton solution, with spectral parameters k
1 and λ
1 are conjugate. We also draw some typical images of 1-soliton solution. The 2-soliton solutions for cnNLS equation are derived and their asymptotic behaviours are discussed. After that we discuss the dynamic behaviour of the two waves in 2-soliton solution under the condition of different spectral parameters values.
Quantum approximate optimization algorithm in non-Markovian quantum systems
Authors: Yue Bo , Xue Shibei , Pan Yu , Jiang Min
Published: September 2023

Although quantum approximate optimization algorithm (QAOA) has demonstrated its quantum supremacy, its performance on Noisy Intermediate-Scale Quantum (NISQ) devices would be influenced by complicated noises, e.g. quantum colored noises. To evaluate the performance of QAOA under these noises, this paper presents a framework for running QAOA on non-Markovian quantum systems which are represented by an augmented system model. In this model, a non-Markovian environment carrying quantum colored noises is modelled as an ancillary system driven by quantum white noises which is directly coupled to the corresponding principal system; i.e. the computational unit for the algorithm. With this model, we mathematically formulate QAOA as piecewise Hamiltonian control of the augmented system, where we also optimize the control depth to fit into the circuit depth of current quantum devices. For efficient simulation of QAOA in non-Markovian quantum systems, a boosted algorithm using quantum trajectory is further presented. Finally, we show that non-Markovianity can be utilized as a quantum resource to achieve a relatively good performance of QAOA, which is characterized by our proposed exploration rate.
Study on the X-Ray Re-brightening Signature of GRB 220117A
Authors: Zhao Li-Tao
Published: September 2023

The Swift/XRT detected the X-ray afterglow of long burst GRB 220117A, which began to rebrighten 300 s after triggering and followed a single power-law decay segment after thousands of seconds of the orbital observation gap. This segment is different from the shallow decay segment (plateau) and flare, and may belong to a giant X-ray bump. We investigated this segment by the fall-back accretion model and found that the model can interpret this segment with reasonable parameter values. Within this physical model scenario, the fall-back accretion rate reaches a peak value ∼1.70 × 10−5
M
⊙ s−1 around 300 s in the central engine frame, which is compatible with the late mass supply rate of some low-metallicity massive progenitor stars. The initial black hole (BH) spin is

a

0

=

0.64

−
0.26

+
0.24

and implies that this re-brightening signature requires a larger BH spin. The total accretion mass during the fall-back process is M
acc = (3.09 ± 0.02) × 10−2
M
⊙. The jet energy from the fall-back accretion is (9.77 ± 0.65) × 1052 erg, with a ratio of 0.066 to the isotropic-equivalent radiation energies of the GRB prompt phase in the 1–104 keV band. The fall-back radius r

p
corresponding to the peak time of fall-back t

p
is (3.16 ± 0.05) × 1010 cm, which is consistent with the typical radius of Wolf–Rayet stars. In summary, our results provide additional support for the origin of the long burst from the core collapse of Wolf–Rayet stars, and its late central engine activity is likely due to the fall-back accretion process.
Detection of Cu(II) in water by using N, S co-doped carbon dots
Authors: Bisauriya Ramanand , Antonaroli Simonetta , Cabibbo Marcello , Pizzoferrato Roberto
Published: September 2023

Determination of Cu(II) ions in surface and drinking water is a high-priority issue both for the environment and human health. Here, we report on the preparation via a hydrothermal method of stable water suspensions of N and S co-doped carbon dots. This material demonstrated selective sensitivity to the presence of copper in water with the appearance of a characteristic absorption band at 658 nm resulting in a visual color variation from orange to dark brown. The colorimetric measurement, carried out by recording the difference between the absorbance at two wavelengths, showed a good linear dependence on the ion concentration from 1 to 100 μM with a lower limit of detection of 300 nM, significantly below the values set by health and environmental organizations. The sensing method is simply based on the addition of the contaminated sample to the carbon dot solution without any other reagents or previous treatment. Moreover, the sensing solution showed stability for at least 6 months after preparation.
Hydrophilic silver nanoparticles for the treatment of water polluted by heavy metals
Authors: Bertelà F. , Bellingeri A. , Burratti L. , Prosposito P. , Di Vona M. L. , Sgreccia E. , Corsi I. , Marsotto M. , Iucci G. , Battocchio C. , Venditti I.
Published: September 2023

Hydrophilic silver nanoparticles (AgNPs) are widely used in advanced biotechnologies, due to their versatile, easy, cheap preparations and due to their peculiar physico-chemical properties. It is well known that their surface functionalization plays a key role in defining the chemical-physical behaviour of AgNPs. If used for monitoring and remediation of heavy metals polluted water, the surface functionalization can direct the selectivity and sensitivity of the nanomaterial. Moreover, different capping agents can also induce different ecotoxicity. In this framework AgNPs are synthetises and properly functionalized using different capping agent, such as citrate (Cit), sodium 3 mercapto-1-propansulphonate (3MPS), L-cysteine (Lcys) and glutathione (GSH). The opportune choice of these capping agents induces size control (in the range of Ø = 2-30 nm) and make available selectively detection of heavy metal ions, such as Co(II), Hg (II) or Fe (III). These investigations confirmed that the multiple functionalized AgNPs are amazing and promising systems for monitoring and treatment of heavy metals polluted water.