bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on water blocking and residue damage mechanism of fracturing fluid in Yongjin tight reservoirs
Authors: Chen Xiaochun , Zhang Guangming , Ding Ran , Zheng Dianxin , Yang Zaiguang , Sun Zhonghua , Zhou Fujian , Wang Daobing
Published: April 2024

The existing reservoir in the Yongjin block exhibits an extremely low matrix permeability, posing challenges in precisely evaluating the damage caused by fracturing fluid using traditional core flow experimental methods. Currently, there is no established quantitative method for characterizing the degree of damage. In this study, we integrated online nuclear magnetic resonance, microscopic computed tomography, and core displacement experimental techniques, pioneering a novel approach to evaluate damage in deep tight oil reservoirs subjected to hydraulic fracturing. We analyzed the influence patterns of key factors such as backflow pressure differential, shut-in time, invasion volume, and residual retention on rock matrix damage in the operational area. The study unveiled the mechanisms behind water sensitivity, water block, and fracturing fluid retention damage among oil, water, and rock. The results indicate that water sensitivity damage is less than 20%, primarily occurring within large pores. Water block damage can significantly reduce the residual oil permeability. Experimental findings suggest that optimizing liquid backflow with a pressure differential and well shut-in time set at 5 MPa and 9 days can markedly reduce the intrusion volume of gel-breaking fluid, restoring the residual oil permeability. Under high-pressure differential conditions, residual fracturing fluid can infiltrate the rock matrix, resulting in pore damage. Additionally, it can accumulate on the fracture surfaces, thereby reducing the permeability of microfractures.
High-responsivity, high-detectivity, broadband infrared photodetector based on MoS2/BP/MoS2 junction field-effect transistor
Authors: Shu Xinrui , Wu Jianfeng , Zhong Fan , Zhang Xinlei , Fu Qiang , Han Xu , Zhang Jialin , Lu Junpeng , Ni Zhenhua
Published: April 2024

Sensitivity stands as a critical figure of merit in assessing the performance of a photodetector and can be characterized by two distinct parameters: responsivity or detectivity. Simultaneous optimization of these two parameters is essential to ensure the applicability of a single detector across various scenarios, yet it remains a persistent challenge for mid-infrared photodetector. Here, we demonstrate that the construction of a photoconductive detector based on a MoS2/BP/MoS2 npn junction field-effect transistor configuration can effectively balance the tradeoffs between photoresponsivity and detectivity. In this device, the black phosphorus layer serves as the channel, while the top and bottom MoS2 layers act as photogates to boost the photocurrent. Consequently, a high-performance room-temperature-operating mid-infrared photodetector with a responsivity and detectivity reaching 9.04 A W−1 and 5.36 × 109 cm Hz1/2 W−1 (1550 nm), and 7.25 A W−1 and 4.29 × 109 cm Hz1/2 W−1 (3600 nm) is achieved. Our study provides an alternative structural design, enabling the applications of mid-infrared photodetectors across multiple scenarios.
Ab initiopath integral Monte Carlo simulations of warm dense two-component systems without fixed nodes: Structural properties
Authors: Dornheim Tobias , Schwalbe Sebastian , Böhme Maximilian P. , Moldabekov Zhandos A. , Vorberger Jan , Tolias Panagiotis
Published: April 2024

We present extensive new ab initio path integral Monte Carlo (PIMC) results for a variety of structural properties of warm dense hydrogen and beryllium. To deal with the fermion sign problem—an exponential computational bottleneck due to the antisymmetry of the electronic thermal density matrix—we employ the recently proposed [Y. Xiong and H. Xiong, J. Chem. Phys. 157, 094112 (2022); T. Dornheim et al., J. Chem. Phys. 159, 164113 (2023)] ξ-extrapolation method and find excellent agreement with the exact direct PIMC reference data where available. This opens up the intriguing possibility of studying a gamut of properties of light elements and potentially material mixtures over a substantial part of the warm dense matter regime, with direct relevance for astrophysics, material science, and inertial confinement fusion research.
Modulation effect of uniform flow on three-dimensional freak wave generation in arbitrary water depth
Authors: Li Shaofeng , Xie Xiaohui , Chen Dake , Song Jinbao
Published: April 2024

In arbitrary water depths, the influence of uniform flow, which includes transverse and longitudinal flows, on the generation of three-dimensional (3D) freak waves is examined. A modified Davey–Stewartson equation is derived using potential flow theory and the multiscale method. This equation describes the evolution of 3D freak wave amplitude under the influence of uniform flow. The relationship between two-dimensional (2D) modulational instability (MI) and the generation of 3D freak waves, as represented by the modified 3D Peregrine Breather solution, is explored. The characteristics of 2D MI depend on the orientation of the longitudinal and transverse perturbations. In shallow waters, the generation of freak waves by MI is challenging due to the minimal orientation difference, and longitudinal flows hardly affect the occurrence of MI. Variations in relative water depth can contribute to forming shallow-water freak waves. In finite-depth waters, oblique modulation leads to MI, whereas in deep and infinite-depth waters, longitudinal modulation gains significance. In environments of finite-depth, deep, and infinite-depth waters, the divergence (convergence) effect of longitudinal favorable (adverse) currents reduces (increases) the MI growth rate and suppresses (facilitates) freak wave generation.
Skyrmionium dynamics on a racetrack in the presence of a magnetic defect
Authors: Vigo-Cotrina H. , Navarro-Vilca S. , Urcia-Romero S.
Published: April 2024

Exotic topological textures known as skyrmioniums can stabilize in different types of ferromagnetic nanostructures. They possess a topological charge of Q=0 and can move in straight lines unaffected by the skyrmion Hall effect. In this work, using micromagnetic simulations, we study the behavior of a skyrmionium when a polarized spin current transports it along a racetrack in the presence of a semicircular magnetic defect with different Dzyaloshinskii–Moriya interaction values. As a first step, we obtained the perpendicular uniaxial anisotropy (Kz) and the Dzyaloshinskii–Moriya constants (Dint) for which it is possible to form a skyrmionium in the racetrack. Our results show that the higher the Kz value, the higher the Dint values necessary to stabilize the skyrmionium. Furthermore, interaction energies between the skyrmionium and the semicircular defect are presented. The results show that the interaction energy can be attractive or repulsive, depending on the Dzyaloshinskii–Moriya defect interaction constant (Dintdef). Finally, we conclude that using these types of defects and a spin-polarized current, the motion of the skyrmionium can be either modified in a specific way or even blocked.
The Janus layered metamaterial modulated by liquid crystal with multitasking of different logic gates and mode-switching biosensing
Authors: Sui Jun-Yang , Liao Si-Yuan , Zou Jia-Hao , Zhang Hai-Feng
Published: April 2024

A Janus layered metamaterial (JLM) operating in the terahertz (THz) region is proposed, which increases the direction dimension to manipulate the propagation of electromagnetic waves (EWs) through the introduction of nonlinear Kerr media. It achieves multi-scale multitasking with different logic gates and mode-switching biosensing, making a breakthrough on traditional single-function and single-scale THz devices. Due to the electro-optical effect, the liquid crystal (LC) is adjusted by the electric field, and the sharp transmission peak generated by the located defect mode resonance can be used to realize the forward scale logic product gate and the backward scale exclusive NOR gate. In addition, by locking the sharp transmission peak, the biosensing can have different detection ranges under the LC modulation. Therefore, when EWs propagate forward and backward, the mode switching of different biosensing categories with a glucose concentration of 300–550 g/l, creatinine concentration of 80.9–85.28 μmol/l, and the blood component in refractive index of 1.33–1.38 can be realized. The JLM proposed provides a possibility for the design of the chip-level compact optical integrated circuit and offers a new idea for multi-purpose biomedical detection, owning certain research value.
Torsional parallel plate flow of Herschel–Bulkley fluids with wall slip
Authors: Gryparis Evgenios , Georgiou Georgios C.
Published: April 2024

The effect of wall slip on the apparent flow curves of viscoplastic materials obtained using torsional parallel plate rheometers is analyzed by considering Herschel–Bulkley fluids and assuming that slip occurs above the slip yield stress τc, taken to be lower than the yield stress, τ0. When the rim shear stress τR is below τc, the exerted torque is not sufficient to rotate the disk. When τc<τR≤τ0 the material is still unyielded but exhibits wall slip and rotates as a solid at half the angular velocity of the rotating disk. Finally, when τR>τ0, the material exhibits slip everywhere and yields only in the annulus r0≤r≤R, where r0 is the critical radius at which the shear stress is equal to the yield stress and R is the radius of the disks. In the general case, the slip velocity, which varies with the radial distance, can be calculated numerically and then all quantities of interest, such as the true shear rate, and the two branches of the apparent flow curve can be computed by means of closed form expressions. Analytical solutions have also been obtained for certain values of the power-law exponent. In order to illustrate the effect of wall slip on the apparent flow curve and on the torque, results have been obtained for different gap sizes between the disks choosing the values of the rheological and slip parameters to be similar to reported values for certain colloidal suspensions. The computed apparent flow curves reproduce the patterns observed in the experiments.
Influence of angle of attack on the semi-sealed cylindrical shell during high-speed water entry
Authors: Xia Shengsheng , Wei Yingjie , Wang Cong
Published: April 2024

The fluid–structure interaction based on STAR-CCM+ and ABAQUS collaborative simulation is adopted in this paper, which is combined with the overset mesh technology, and the cavity evolution and motion characteristics of the semi-sealed cylindrical shell with the angle of attack during high-speed water entry are studied. The results show that the shell with an angle of attack experiences significant deflection after penetrating into the water, which is due to the fluid hitting the upper wall of the shell and generating a large torque. The deformation of the horizontally placed shell is much more obvious than that of a vertically placed shell during water entry. Due to the deformation of the shell, the direction of the fluid's force can be changed, resulting in a horizontal component force, causing a horizontal movement of the horizontal shell during water entry. As the angle of attack decreases, the volume of fluid entering into the shell gradually decreases, resulting in a decrease in the volume of fluid flowing out of the shell. The shell with an angle of attack less than 75° causes the top wall to come into contact with the water surface during the deflection process, which also generates new cavities below.
Genome-wide association studies identifies genetic loci related to fatty acid and branched-chain amino acid metabolism and histone modifications under varying nitrogen treatments in safflower (Carthamus tinctorius)
Authors: Ali Fawad , Arif Mian A. R. , Ali Arif , Nadeem Muhammad A. , Aksoy Emre , Bakhsh Allah , Khan Shahid U. , Kurt Cemal , Tekdal Dilek , Ilyas Muhammad K. , Hameed Amjad , Chung Yong S. , Baloch Faheem S.
Published: April 2024

Effective identification and usage of genetic variation are prerequisites for developing nutrient-efficient cultivars. A collection of 94 safflower (Carthamus tinctorius) genotypes (G) was investigated for important morphological and photosynthetic traits at four nitrogen (N) treatments. We found significant variation for all the studied traits except chlorophyll b (chl b) among safflower genotypes, nitrogen treatments and G × N interaction. The examined traits showed a 2.82–50.00% increase in response to N application. Biological yield (BY) reflected a significantly positive correlation with fresh shoot weight (FSW), root length (RL), fresh root weight (FRW) and number of leaves (NOL), while a significantly positive correlation was also observed among carotenoids (C), chlorophyll a (chl a), chl b and total chlorophyll content (CT) under all treatments. Superior genotypes with respect to plant height (PH), FSW, NOL, RL, FRW and BY were clustered into Group 3, while genotypes with better mean performance regarding chl a, chl b C and CT were clustered into Group 2 as observed in principal component analysis. The identified eight best-performing genotypes could be useful to develop improved nitrogen efficient cultivars. Genome-wide association analysis resulted in 32 marker-trait associations (MTAs) under four treatments. Markers namely DArT-45481731, DArT-17812864, DArT-15670279 and DArT-45482737 were found consistent. Protein–protein interaction networks of loci associated with MTAs were related to fatty acid and branched-chain amino acid metabolism and histone modifications.
A review of Palaemonella (Decapoda: Caridea: Palaemonidae), with clarification of the taxonomic status of Cuapetes americanus, Eupontonia and Vir
Authors: Frolová Pavlína , van der Veer Eva , Fransen Charles H. J. M. , Ďuriš Zdeněk
Published: April 2024

The pantropical genus Palaemonella Dana, 1852 (Caridea: Palaemonidae) currently includes 27 species of free-living and symbiotic marine shrimps. The monophyly of Palaemonella with respect to several closely related genera, however, has been questioned by recent analyses. We tested the monophyly of Palaemonella based on multigene phylogenetic analysis and the genus was revealed to be a paraphyletic assemblage by inclusion of species of the genera Eupontonia Bruce, 1971 and Vir Holthuis, 1952, and two genetic lineages of the western Atlantic Cuapetes americanus (Kingsley, 1878). We recognise one of the latter lineages as the previously described Periclimenes rhizophorae Lebour, 1949. Eupontonia and Vir are synonymised with Palaemonella. We also transfer Cuapetes americanus and Periclimenes rhizophorae to Palaemonella. Species previously assigned to Vir were revised; V. colemani Bruce, 2003, V. orientalis (Dana, 1852), V. philippinensis Bruce & Svoboda, 1984 and V. smiti Fransen & Holthuis, 2007 are regarded as valid species of Palaemonella; Vir longidactylus Marin, 2008 is synonymised with P. smiti; and the status of V. euphyllius Marin & Anker, 2005 remains unresolved. Palaemonella is currently regarded as a taxon with variable states of two main diagnostic characters, i.e. the plesiomorphic mandibular palp (fully reduced in P. americana) and the hepatic tooth (fully reduced in former species of Vir and Eupontonia – evidently due to symbiotic modes of life). ZooBank: urn:lsid:zoobank.org:pub:7EEBC655-7EDE-4E46-BCB2-2A3BA16ED7DD
A time-resolved single-cell roadmap of the logic driving anterior neural crest diversification from neural border to migration stages
Authors: Kotov Aleksandr , Seal Subham , Alkobtawi Mansour , Kappès Vincent , Ruiz Sofia Medina , Arbès Hugo , Harland Richard M. , Peshkin Leonid , Monsoro-Burq Anne H.
Published: April 2024

Neural crest cells exemplify cellular diversification from a multipotent progenitor population. However, the full sequence of early molecular choices orchestrating the emergence of neural crest heterogeneity from the embryonic ectoderm remains elusive. Gene-regulatory-networks (GRN) govern early development and cell specification toward definitive neural crest. Here, we combine ultradense single-cell transcriptomes with machine-learning and large-scale transcriptomic and epigenomic experimental validation of selected trajectories, to provide the general principles and highlight specific features of the GRN underlying neural crest fate diversification from induction to early migration stages using
Xenopus
frog embryos as a model. During gastrulation, a transient neural border zone state precedes the choice between neural crest and placodes which includes multiple converging gene programs. During neurulation, transcription factor connectome, and bifurcation analyses demonstrate the early emergence of neural crest fates at the neural plate stage, alongside an unbiased multipotent-like lineage persisting until epithelial–mesenchymal transition stage. We also decipher circuits driving cranial and vagal neural crest formation and provide a broadly applicable high-throughput validation strategy for investigating single-cell transcriptomes in vertebrate GRNs in development, evolution, and disease.
Effect of skull morphology on fox snow diving
Authors: Yuk Jisoo , Pandey Anupam , Park Leena , Bemis William E. , Jung Sunghwan
Published: April 2024

Certain fox species plunge-dive into snow to catch prey (e.g., rodents), a hunting mechanism called mousing. Red and arctic foxes can dive into snow at speeds ranging between 2 and 4 m/s. Such mousing behavior is facilitated by a slim, narrow facial structure. Here, we investigate how foxes dive into snow efficiently by studying the role of skull morphology on impact forces it experiences. In this study, we reproduce the mousing behavior in the lab using three-dimensional (3D) printed fox skulls dropped into fresh snow to quantify the dynamic force of impact. Impact force into snow is modeled using hydrodynamic added mass during the initial impact phase. This approach is based on two key facts: the added mass effect in granular media at high Reynolds numbers and the characteristics of snow as a granular medium. Our results show that the curvature of the snout plays a critical role in determining the impact force, with an inverse relationship. A sharper skull leads to a lower average impact force, which allows foxes to dive head-first into the snow with minimal tissue damage.
The structured narrative interview
Authors: Moenandar Sjoerd-Jeroen , Basten Floor , Taran Giti , Panagoulia Ariadni , Coughlan Gemma , Duarte Joana
Published: April 2024

In this study, Greimas’s work on narrative structure is used to improve a specific practice: the research interview. In the social sciences, narrative interviewing often consists of collecting data from which a narrative is then constructed through analysis afterwards. In the interview method presented here, the interviewer instead prompts the interviewee to construct a narrative. We introduce the method, contextualize it by comparing it to previous and contemporary interview methods, and illustrate it with a small, sociolinguistic study: students (n = 12) from a humanities faculty and a science and engineering faculty at a Dutch university were interviewed about experiences with the use of different languages than the language of instruction in an international learning environment. The method allowed for smooth data collection, due to its narratively structured questioning and consequent rich data. Moreover, using narrative structures to guide the interview also facilitated easy analysis and comparison of the stories.
The danger of the spread of
Ralstonia solanacearum
on potato crops worldwide and potential mitigation options
Authors: Okiro Lilian A. , Mulwa Richard M. , Oyoo Maurice E. , Nyalala Samuel
Published: April 2024

Potato is a major crop that is consumed by over one billion people worldwide. However, production is hampered by diseases such as viral infections, late blight, and bacterial wilt. Bacterial wilt disease caused by
Ralstonia solanacearum
is the second most prevalent disease after blight, and its effects are exacerbated by both global trade and climate change. The extent of the disease devastation varies by country, with more serious consequences evident in major potato-producing countries. The
Ralstonia
species complex (RSSC) is a group of pathogenic strains that spread through the use of infected seed potato, soils, water run-offs, plant debris, or contaminated farm equipment and propagation material. The elements that contribute to the rapid spread of bacterial wilt disease in potato are discussed in this review article, and a disease-control strategy is proposed. Understanding how
R. solanacearum
spreads through international trade is critical for developing effective mitigation and management techniques to control and limit the spread of this damaging phytopathogen.
Mitochondrial sites of contact with the nucleus
Authors: Campanella Michelangelo , Kannan Brindha
Published: April 2024

Membrane contact sites (MCS) between mitochondria and the nucleus have been recently described. Termed nucleus associated mitochondria (NAM), they prime the expression of genes required for cellular resistance to stressors, thus offering a tethering mechanism for homeostatic communication. Here, we discuss the composition of NAM and their physiological and pathological significance.
Treg–tissue cell interactions in repair and regeneration
Authors: Loffredo Lucas F. , Savage Thomas M. , Ringham Olivia R. , Arpaia Nicholas
Published: April 2024

Regulatory T (Treg) cells are classically known for their critical immunosuppressive functions that support peripheral tolerance. More recent work has demonstrated that Treg cells produce pro-repair mediators independent of their immunosuppressive function, a process that is critical to repair and regeneration in response to numerous tissue insults. These factors act on resident parenchymal and structural cells to initiate repair in a tissue-specific context. This review examines interactions between Treg cells and tissue-resident non-immune cells—in the context of tissue repair, fibrosis, and cancer—and discusses areas for future exploration.
Master constraint approach to quantum-reduced loop gravity
Authors: Mäkinen Ilkka
Published: April 2024

We introduce a master constraint operator on the kinematical Hilbert space of loop quantum gravity representing a set of gauge conditions which classically fix the densitized triad to be diagonal. We argue that the master constraint approach provides a natural and systematic way of carrying out the quantum gauge-fixing procedure which underlies the model known as quantum-reduced loop gravity. The Hilbert space of quantum-reduced loop gravity is obtained as a particular space of solutions of the gauge-fixing master constraint operator. We give a concise summary of the fundamental structure of the quantum-reduced framework, and consider several possible extensions thereof, for which the master constraint formulation provides a convenient starting point. In particular, we propose a generalization of the standard Hilbert space of quantum-reduced loop gravity, which may be relevant in the application of the quantum-reduced model to physical situations in which the Ashtekar connection is not diagonal.
Mitigating waveguide loss in Ge–Sb–Se chalcogenide glass photonics
Authors: Han Fengbo , Niu Yunfei , Zhang Yan , Gong Jue , Yu Shaoliang , Du Qingyang
Published: April 2024

Minimizing propagation loss within waveguides remains a central objective across diverse photonic platforms, impacting both linear lightwave transmission and nonlinear wavelength conversion efficiencies. Here, we present a method to mitigate waveguide loss in Ge28Sb12Se60 chalcogenide glass, a material known for its high nonlinearity, broad mid-infrared transparency, and significant potential for mid-IR photonics applications. By applying a sacrifical oxide layer to eliminate etching residues and a subsequent waveguide thermal reflow to smooth lithography-induced line edge roughness, we successfully reduced the waveguide loss down to 0.8 dB cm−1 at 1550 nm wavelength. This represents the best result in small-core and high-index-contrast Ge28Sb12Se60 channel waveguides. Our approach paves the way for low-loss, on-chip chalcogenide photonic devices.
Broad band modulation of two-dimensional Mo1-x
W
x
S2 by variational compositions
Authors: Huang Zuqiang , Zhao Hongquan , Liu Shaoxiang , Liang Xianxiao , Chen Yin , Wu Zepeng , Liu Xiu , Yuan Hongkuan , Wang Chunxiang , Shi Xuan
Published: April 2024

Precisely tuning bandgap enables tailored design of materials, which is of crucial importance for optoelectronic devices. Towards this end, ternary Mo1-x
W
x
S2 monolayers with continually variational transition metal compositions are synthesized by precisely control of the precursors and growth temperatures in the chemical vapor deposition process, and thus to manipulate the bandgap of the monolayers. Energy dispersive x-ray spectroscopy demonstrates that the composition of the ternary Mo1-x
W
x
S2 monolayers can be effectively modulated by the precursors and synthesizing temperatures. Frequency and intensity of the Raman and photoluminescent peaks of the Mo1-x
W

x

S2 monolayers are continually modulated by the variational Mo and W compositions. The maximum of 0.148 eV bandgap modulation is achieved by modulating the transition metal compositions, which is highly consistent to the calculated 0.158 eV by first-principles theory. Photodetectors based on the Mo1-x
W
x
S2 monolayers are fabricated and U-shape of photoresponse characteristics are demonstrated as x change from 0 to 1 under the same measurement conditions. The estimated photocurrent, photoresponsivity and external quantum efficiency show that the minimum values appear at the composition of x = 0.5, while the maximum values appear at x = 1. The results illustrate an excellent level of control on the band structure of two-dimensional ternary Mo1-x
W
x
S2 by precisely control of the transition metal compositions.
Plasma-deposited reactive species assisted synthesis of colloidal zinc-oxide nanostructures
Authors: Kutasi Kinga , Péter László , Tóth Zsolt
Published: April 2024

A surface-wave microwave discharge is applied to deposit reactive oxygen and nitrogen species (RONS) into the liquid subsequently used as a medium for laser ablation of a Zn metallic target. It is shown that during laser ablation in plasma-treated liquids the H2O2 concentration decreases, while in deionized water (DIW) significant H2O2 is produced. Meanwhile, the pH—initially adjusted by applying reductive metals—increases in the acidic liquids and decreases in the alkaline ones. During months of storage the pH of colloids stabilize around pH 6, which insures the long-term stability of RONS. It is demonstrated that in DIW metallic Zn NPs are created, which gradually oxidize during storage, while in the plasma-treated liquids ZnO NPs are produced with the mean size of 18 nm. In the alkaline plasma-treated liquid the NPs form large aggregates, which slows the dissolution of NPs. In the acidic and neutral solutions besides NPs nanosheets are also formed, which during storage evolve into nanosheet networks as a result of the dissolution of NPs. The band gap of the colloidal ZnO is found to decrease with the formation of aggregates and nanosheet networks. The ZnO NPs ablated in plasma-treated liquids exhibit a high-intensity visible emission covering the green-to-red spectral region. The photoluminescence spectra is dominated by the orange-red emission—previously not detected in the case of laser-ablated ZnO NPs and attributed to the interstitial Zn and oxygen sites—and the yellow emission, which can be attributed to the OH groups on the surface. It is shown that during months of storage, due to the dissolution of NPs and formation of nanosheets, the intensity of the visible emission decreases and shifts to the blue-green spectral region.
Carbon nanostructures synthesis by catalyst-free atmospheric pressure plasma jet
Authors: Neira-Velázquez María Guadalupe , Ku-Herrera José de Jesús , Narro-Céspedes Rosa Idalia , Flores-Villaseñor Sergio Enrique , Cortez-Garza Yuvicela Leticia , Cuellar-Gaona Claudia Gabriela , Soria-Arguello Gustavo
Published: April 2024

In this study, carbon nanostructures were synthesized utilizing a warm plasma jet at atmospheric pressure in a continuous and catalyst-free process. The procedure and apparatus were designed and constructed in our laboratory. Plasma was generated with 600 W of electrical energy, using a high-voltage, high-frequency alternating current power source. The working gas utilized was a propane/butane mixture, with a concentration ratio of 60:40, respectively. A production rate of 300 mg min−1 of powdered material was achieved, with a particle size between 20 and 100 nm. The product was characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, Raman spectroscopy, x-ray diffraction, and transmission electron microscopy. Results show the formation of multilayer carbon nanostructures with a low content of functional groups; the obtained material presented structural defects and amorphous carbon. This work demonstrates that, with adequate control, warm plasma jet discharges can be employed for the synthesis of carbon nanostructures. The process is scalable and can be utilized for hydrocarbon reforming and hydrogen production. However, further studies are needed to improve the quality of the nanostructures and process efficiency. The synthesized material can potentially be used in gas adsorption or in the manufacture of polymeric nanocomposites with enhanced thermal, electrical, and mechanical properties.
Chain dynamics of alternating polymers P(C
n
EG4)
Authors: Bichler Karin J , Jakobi Bruno , Schneider Gerald J
Published: April 2024

Alternating or sequence defined polymers attract the attention of an increasing number of researchers recently. Due to their different blocks, they are very customizable and material properties can be tuned. In this publication, we present dynamical studies with focus on polymer dynamics, investigated by rheology and fast field cycling (FFC) NMR. The molecular weight dependencies of the relaxation time and zero-shear viscosity could hint to entanglement effects; however, the spectral shape of the viscoelastic data resembles the polymer dynamics of unentangled melts. Taking both techniques into account, i.e. rheology and FFC NMR leads to the conclusion that the relaxation spectra of the alternating polymer are similar to those of linear polymers.
Spin-valley polarization and tunneling magnetoresistance in monomer, dimer, and trimer magnetic silicene superlattices
Authors: Rojas-Briseño J G , Villasana-Mercado P , Molina-Valdovinos S , Oubram O , Rodríguez-Vargas I
Published: April 2024

Monomer, dimer and trimer semiconductor superlattices are an alternative for bandgap engineering due to the possibility of duplicate, triplicate, and in general multiply the number of minibands and minigaps in a specific energy region. Here, we show that monomer, dimer, and trimer magnetic silicene superlattices (MSSLs) can be the basis for tunable magnetoresistive devices due to the multiplication of the peaks of the tunneling magnetoresistance (TMR). In addition, these structures can serve as spin-valleytronic devices due to the formation of two well-defined spin-valley polarization states by appropriately adjusting the superlattice structural parameters. We obtain these conclusions by studying the spin-valley polarization and TMR of monomer, dimer, and trimer MSSLs. The magnetic unit cell is structured with one seed A with positive magnetization, and one, two, or three seeds B with variable magnetization. The number of B seeds defines the monomer, dimer, and trimer superlattice, while its magnetic orientation positive or negative the parallel (PM) or antiparallel magnetization (AM) superlattice configuration. The transfer matrix method and the Landauer–Büttiker formalism are employed to obtain the transmission and transport properties, respectively. We find multiplication of TMR peaks in staircase fashion according to the number of B seeds in the superlattice unit cell. This multiplication is related to the multiplication of the minibands which reflects as multiplication of the descending envelopes of the conductance. We also find well-defined polarization states for both PM and AM by adjusting asymmetrically the width and height of the barrier-well in seeds A and B.
Thermal conductivity of irregularly shaped nanoparticles from equilibrium molecular dynamics
Authors: Li Hongfei , Zhu Yuanxu , Chu MengFan , Dong Haikuan , Zhang Guohua
Published: April 2024

The computation of thermal conductivity for finite nanoparticulate systems, particularly those of irregular shapes, poses significant challenges. The nonequilibrium molecular dynamics (NEMD) methods has been extensively utilized in numerous prior studies for the computation of thermal conductivity of nanoparticles. One of our recent works (Dong et al 2021 Phys. Rev. B 103 035417) proposed that equilibrium molecular dynamics (EMD) methods can be used for the simulation of thermal conductivity of finite-scale systems and demonstrated their equivalence to NEMD methods. In this study, we investigated the application of the (EMD) approach for the computation of thermal conductivity in zero-dimensional nanoparticles. In our initial step, we merged both methodologies to substantiate the equivalence in thermal conductivity calculation for cube and cylinder nanoparticles. After filtering the data, we confirmed the usefulness of EMD for evaluating the thermal conductivity of zero-dimensional materials. The NEMD method faces challenges in accurately predicting thermal conductivity in nanoparticle systems with a varying cross-sectional area along the transport direction, whereas EMD methods can be utilized to estimate thermal conductivity when the volume is known. In a subsequent study, we used the state-of-the-art machine learning potential to calculate the thermal conductivity of spherical nanoparticles and compared the results with those obtained using the classical Tersoff potential. Ultimately, we predicted the thermal conductivity of nanoparticles with various geometries in all directions. Our findings collectively demonstrate the simplicity and effectiveness of employing EMD methods for calculating thermal conductivity in nanoparticle systems, thereby opening up new avenues for investigating thermal transport properties in particle systems as well as nanopders.
Superconductivity in monolayer Janus titanium-sulfur hydride (TiSH) at ambient pressure
Authors: Munib ul Hassan Noor ul Taqi M , Pinsook Udomsilp
Published: April 2024

Janus two dimensional (2D) materials are new and novel materials. As they break out-of-plane symmetry, they possess several fascinating properties which can be applied in catalytic reactions and opto-electronics. Recent synthesis of MoSH and the prediction of phonon-mediated superconductivity have opened a new way to investigate the properties of hydrogenated Janus materials (Novoselov et al 2004 Science
306 666–9; Mehta et al 2023 Solid State Commun.
375 115347; Naik et al 2023 Comput. Theor. Chem.
1228 114278). In this work, we performed the density functional theory calculations to demonstrate that titanium sulfur hydride (TiSH) is dynamically stable and becomes phonon-mediated superconductor with the superconducting critical temperature, Tc
= 9.24 K with the corresponding value of electron–phonon coupling constant, λ = 0.71, in the weak interaction limits, under ambient conditions. Eliashberg spectral function

α
2

F

(
ω
)

was well converged for dense grid of q1 × q2 × q3 = 12 × 12 × 1 and nk1 × nk2 × nk3 = 140 × 140 × 1. The effect of smearing broadening was also considered for determining well converged value of Tc
and λ. Figure 5(b) shows that after smearing broadening of 0.02 Ry, λ shows convergent values, and subsequent changes are as low as less that 5% of the peak value. Overall, our findings predicted a new member in the 2D Janus hydride family with possible applications in 2D nanomaterials and superconducting devices applications.
Radar-optical fusion detection of UAV based on improved YOLOv7-tiny
Authors: Tang Hao , Xiong Wei , Dong Kai , Cui Yaqi
Published: April 2024

This study presents a radar-optical fusion detection method for unmanned aerial vehicles (UAVs) in maritime environments. Radar and camera technologies are integrated to improve the detection capabilities of the platforms. The proposed method involves generating regions of interest (ROI) by projecting radar traces onto optical images through matrix transformation and geometric centroid registration. The generated ROI are matched with YOLO detection boxes using the intersection-over-union (IoU) algorithm, enabling radar-optical fusion detection. A modified algorithm, called SPN-YOLOv7-tiny, is developed to address the challenge of detecting small UAV targets that are easily missed in images. In this algorithm, the convolutional layers in the backbone network are replaced with a space-to-depth convolution, and a small object detection layer is added. In addition, the loss function was replaced with a normalized weighted distance loss function. Experimental results demonstrate that compared to the original YOLOv7-tiny method, SPN-YOLOv7-tiny achieves an improved mAP@0.5 (mean average precision at an IoU threshold of 0.5) from 0.852 to 0.93, while maintaining a high frame rate of 135.1 frames per second. Moreover, the proposed radar-optical fusion detection method achieves an accuracy of 96.98%, surpassing the individual detection results of the radar and camera. The proposed method effectively addresses the detection challenges posed by closely spaced overlapping targets on a radar chart.
Semi-supervised method for visual detection of automotive paint defects
Authors: Jiang Weiwei , Chen Xingjian , He Yike , Wang Xiuxian , Hu Songyu , Lu Minhua
Published: April 2024

Automotive paint defect detection plays a crucial role in the automotive production process. Current research on visual defect detection methods is mainly based on supervised learning, which requires a large number of labeled image samples for model training. The labeling work is not only time consuming but also expensive, seriously hindering the testing and application of these models in practice. To address this issue, this study proposes a new method for automotive paint defect detection based on a semi-supervised training strategy. First, a semi-supervised automotive paint defect detection framework, which can use labeled and unlabeled samples to reduce the cost of data labeling effectively, is presented. Then, a spatial pyramid pooling fast external attention module that introduces an external attention mechanism is proposed to improve the traditional YOLOv7 network structure, called YOLOv7-EA, to obtain good detection performance. This network acts as a detector to generate high-quality pseudo labels for the unlabeled samples, providing additional data to train the model; meanwhile, it performs the final detection task. Lastly, a Wise-intersection over union loss function that considers the quality of the anchor box is introduced to reduce the interference of low-quality samples and improve the convergence speed and detection accuracy of the model. Using this method, we can accomplish the task of automotive paint defect detection with a small number of labeled image samples. Experimental results on the automotive paint defect dataset show that mean average precision (mAp)@.5, mAp@.75, and mAp@.5:.95 are superior to other methods under the condition of 10% and 15% labeled data, achieving good defect detection performance.
Determining the potato samples processed manner with an electronic nose system supported by a machine-learning approach
Authors: Amkor Ali , Aboulkacem Asmae , Bannay Omar El , El Barbri Noureddine
Published: April 2024

Through several studies, electronic nose (E-nose) devices have been demonstrated to serve as useful measurement equipment for the fast and reliable analysis of complex odour profiles in a wide range of fields, including the area of ensuring food safety. In the same perspective, i.e. checking food safety comes this work, where potatoes are assessed using an E-nose principally made of five metal oxide gas sensors supported with a machine learning algorithm, said evaluation is based on their origin fields: naturally treated, treated with chemical NPK fertilizers, or treated with chicken manure. The technique of support vector machines has been exploited for the data obtained from the multi-sensor system in order to distinguish the potato types mentioned by following two methods: a direct method where all the data have been exploited with a rate of success of 91.7%, and a composed method where the classification was first between naturally treated samples and those treated differently with a success rate of 96.7%, then a classification between those treated differently had a 92.5% success rate. A microbiological analysis was also carried out and its results were compared with those obtained by the E-nose. As per the two methods’ results, the distinction of the potato types by the nature of the cultivated fields is possible with the recording of the multisensory system superiority due to response time, low cost, simplicity, and portability.
FCS-YOLO: an efficient algorithm for detecting steel surface defects
Authors: Zhao Chunhua , Fan Yankun , Tan Jinling , Li Qian , Lin Zhangwen , Luo Shun , Chen Xi
Published: April 2024

Due to the imperfection of the manufacturing process and external factors, there may be some defects on the steel surface, which seriously affects the life and availability of the steel. Aiming at the problems of low precision and poor real-time performance in the inspection of steel surface defects in the past, an algorithm named FCS-you only look once (YOLO) was proposed for the inspection of steel surface defects. Firstly, the backbone feature extraction network is reconstructed using FasterNet to reduce the number of model parameters and weight size. Secondly, a new C2f-global attention mechanism module is proposed, which can focus image features more accurately by dynamically adjusting feature response. Finally, the attention mechanism SK is embedded in the feature extraction network to adjust the receptive field of the model, strengthen its feature recognition ability, and effectively improve the detection accuracy of steel surface defects. The test results show that FCS-YOLO has the best detection effect and the fastest detection speed among the comparison models. On the NEU-DET Dataset, the detection accuracy reached 81.8% and the detection speed reached 129.87 frames per second, which met the requirements of accurate and fast detection of strip surface defects.
Realtime 3D reconstruction algorithm based on improved AKAZE and multi-layer feature detection network
Authors: Pan Zihao , Hou Junyi , Su Yan , Lv Yong , Chen Zhong , Yu Lei
Published: April 2024

Simultaneous localization and mapping (SLAM) technology aims to solve the problem of how to determine the trajectory of robots by observing the environment and construct sparse spatial models. And the 3D reconstruction technology can further build dense spatial models based on the pose information. This paper proposes a dense 3D reconstruction algorithm based on improved accelerated-KAZE features and a multi-layer feature detection network. A multi-layer feature detection neural network is constructed to replace the bag-of-words model and optimize the loopback results, which improves the effect of pose estimation. The optimized algorithm improves the mapping effect and construct clear and robust indoor complex models. The pose estimation results show that the optimized algorithm improves the accuracy by 30% compared with ORB-SLAM2. Compared with the mapping effect of Kintinuous, ElasticFusion, ORB-SLAM2 and BundleFusion, the optimized models own the advantages of clearer details, richer information and no split layer.
A 3D printing assisted microfluidic absorbance-based measurement system for biological assay
Authors: Kumar Ankit , Nath Prathul , Das Neeladrisingha , Chatterjee Manisha , Roy Partha , Satapathi Soumitra
Published: April 2024

Development of rapid analytical systems utilizing 3D printing is an emerging area of interest with the potential to provide efficient solutions by integrating multidisciplinary technology without compromising the quality of the system. In this study we report the fabrication of a 3D printing assisted microfluidic based absorbance measurement system, leveraging 3D printing along with integrating miniature optical components for the accurate measurement of biological assays. The developed system is rapid, affordable, and compact, through set of computer-aided design models and fusion deposition modeling 3D printing along with relevant electronic circuitry involving optical components like surface mounting devices. The handheld device features a capacitive touchscreen display, programmed to seamlessly perform MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. The device was employed for assessing the cell viability using Michigan cancer foundation-7 (MCF-7) cell lines over varying concentrations of tamoxifen, reciprocating the MTT assay analysis conducted by using spectrophotometer. The device achieved excellent results which upon comparison with the conventional spectrophotometer-based results have shown a correlation coefficient of 0.98. This compact and rapid absorbance measurement system holds significant potential for evaluating the cytotoxicity of drugs, and further development of innovative analytical devices.
Impact location of metal structures based on time–frequency image features and deep residual network
Authors: Zhang Yu , Zhou Zeye , Rui Xiaobo , Xu Lixin , Li Bin , Ma Chang , Qi Lei
Published: April 2024

Impact location detection plays an important role in the structural health monitoring of metal materials. However, the methods of metal material impact location detection based on physical analysis are often limited by the extraction accuracy of some parameters such as material and structure parameters and time difference calculation. Therefore, this paper develops a deep residual network method for impact location detection, time–frequency characteristic deep residual network (TF-DRN). This method takes the four-channel short-time Fourier transform time–frequency graph as input, uses the unique residual network architecture to automatically extract the advanced features, and then uses the global average pooling layer and the full connection layer to establish the mapping between the advanced features and the impact location, so as to detect the impact location. By introducing regularization and batch normalization, the problems of gradient disappearance and gradient explosion are alleviated, and the generalization and efficiency of impact location detection are further improved. The experimental results show that on an 800 mm × 800 mm × 2.5 mm aluminum plate, the average error of the validation set and the test set are 0.85 cm and 1.33 cm respectively, and the performance of the method is significantly better than that of CNN, ResNet18 and ResNet33 networks.