bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improved dielectric and mechanical properties of aramid fiber reinforced epoxy resin composites by polyethyleneimine grafting
Authors: Du Boxue , Xue Rundong , Kong Xiaoxiao , Chen Yun 
Published: August 2023

Abstract
In this paper, aramid fiber surface is modified by polyethylenimine (PEI) grafting with abundant -NH2 active groups after plasma surface activation treatment. Various aramid fiber reinforced epoxy resin composites (AFRC) are prepared. The effects of PEI grafting on the dielectric and mechanical properties of AFRC are studied. Obtained results show that PEI is successfully grafted onto aramid fiber surface as evidenced by x-ray photoelectron spectroscopy results, and effectively improves the interfacial properties between aramid fiber and epoxy resin. The dielectric properties, including DC conductivity, dielectric constant, and integration charge Q(t) of the composites are improved after optimized modification parameters, and the breakdown strength is increased by up to 23%. These are attributed to the decrease in interfacial polarization and the increase in interfacial bonding strength. Furthermore, the interfacial shear strength of AFRC is increased from 29.5 MPa to 63.7 MPa, which further verifies the improvement of interfacial performance. This paper provides a way to improve the dielectric and mechanical properties of AFRC, which is of great significance for its application in high voltage power equipment.
The cell-centered Finite-Volume self-consistent approach for heterostructures: 1D electron gas at the Si–SiO2 interface
Authors: Mosallanejad Vahid , Li Haiou , Cao Gong , Chiu Kuei-Lin , Dou Wenjie , Guo Guo-ping 
Published: August 2023

Abstract
Achieving self-consistent convergence with the conventional effective-mass approach at ultra-low temperatures (below 4.2 K) is a challenging task, which mostly lies in the discontinuities in material properties (e.g. effective-mass, electron affinity, dielectric constant). In this article, we develop a novel self-consistent approach based on cell-centered finite-volume discretization of the Sturm–Liouville form of the effective-mass Schrödinger equation and generalized Poisson’s equation (FV-SP). We apply this approach to simulate the one-dimensional electron gas formed at the Si–SiO2 interface via a top gate. We find excellent self-consistent convergence from high to extremely low (as low as 50 mK) temperatures. We further examine the solidity of FV-SP method by changing external variables such as the electrochemical potential and the accumulative top gate voltage. Our approach allows for counting electron–electron interactions. Our results demonstrate that FV-SP approach is a powerful tool to solve effective-mass Hamiltonians.
Structural phase transition driven dielectric and optical properties with reduction in band gap in Sr2+ modified BaTiO3 ceramics
Authors: Mallick Jyotirekha , Kumar Ajay , Das Tupan , Pradhan Lagen Kumar , Parida Prakash , Kar Manoranjan 
Published: August 2023

Abstract
Ferroelectric materials with crystal symmetry transition from single phase to multiphase coexistence exhibit anomalous photosensitive properties. The optical properties (optical band gap and photosensitive) found on non-centrosymmetric and centrosymmetric systems achieved research interest because of their interesting behavior. In this regard, the lead-free polycrystalline Ba1−x
Sr
x
TiO3 (BSTO, 0

⩽
x
⩽
0.3

) has been synthesized to explore its crystal structure, dielectric, light absorption, and photocurrent sensing properties for various applications. Both experimental and theoretical studies on BSTO (0

⩽
x
⩽
0.3
)

ceramics confirm the crystal symmetry transition with the reduction of band gap as compared to pristine BaTiO3. This crystal symmetry transition plays an important role in varying the various physical properties as it involves the transition from the polar phase to the non-polar phase. The optical band gap has been estimated experimentally by the Tauc plot method and found that there is a small variation of energy band gap from 3.615 eV to 3.212 eV with Sr substitution. The highest dielectric constant was found to be 5327 at lower frequency on Ba0.76Sr0.24TiO3 after that for further increase in Sr concentration the dielectric constant decreases because of the introduction of the non-polar phase. A strong correlation between crystal structure and physical properties (dielectric, optical, etc.) has been observed. The photocurrent of the samples is significant which reveals that the sample is influenced by the photons. In a nutshell, the present study deepens the understanding of the correlation between crystal structure and various physical properties of BSTO and, hence provides an idea of required design parameters to construct a ferroelectric system for better photosensitive nature suitable for device applications.
Integration of N, P-doped carbon quantum dots with hydrogel as a solid-phase fluorescent probe for adsorption and detection of Fe3+
Authors: Dong Guohua , Lv Qihang , Hao Lijuan , Zhang Wenzhi , Zhang Zhuanfang , Chai Dong-feng , Zhu Min , Zhao Ming , Li Jinlong 
Published: August 2023

Abstract
In this work, a novel nitrogen-phosphorus co-doped carbon quantum dots (N, P-CQDs) hydrogel was developed utilizing the as-synthesized N, P-CQDs and acrylamide (AM) with the existence of ammonium persulfate and N, N′-methylene bisacrylamide (N-MBA). In consistent with pure N, P-CQDs, the N, P-CQDs hydrogel also shows a dramatic fluorescence property with maximum emission wavelength of 440 nm, which can also be quenched after adsorbing iron ions (Fe3+). When the concentration of Fe3+ is 0–6 mmol l−1, a better linear relationship between Fe3+ concentration and the fluorescence intensities can be easily obtained. Additionally, the N, P-CQDs hydrogel exhibits better recyclability. This confirms that the N, P-CQDs hydrogel can be used for adsorbing and detecting Fe3+ in aqueous with on–off–on mode. The fluorescence quenching mainly involves three procedures including the adsorption of Fe3+ by hydrogel, integration of Fe3+ with N, P-CQDs and the transportation of conjugate electrons in N, P-CQDs to the vacant orbits of Fe3+ and the adsorption process follows a pseudo-second-order kinetic model confirmed in the Freundlich isotherm model. In conclusion, this work provides a novel route for synchronously removing and detecting the metal ions in aqueous by integrating N, P-CQDs with hydrogel with better recyclability.
Analysis of travelling waves and propagating supports for a nonlinear model of flame propagation with a p-Laplacian operator and advection
Authors: Díaz Palencia José Luis , Rahman Saeed ur 
Published: August 2023

Abstract
In this paper, we propose a new model to characterize the behaviour of a flame driven by temperature and pressure variables. The model is formulated using a p-Laplacian operator, an advection term, and a nonlinear reaction (considering linear kinetics). First, the uniqueness and boundedness of the weak solutions are demonstrated. Subsequently, traveling wave solutions supported by the geometric perturbation theory are obtained. As a major outcome, minimum traveling wave speeds are shown to exist, for which the associated profiles of the solutions are purely monotonic with exponential behaviour. The assumptions considered in the analytical approach are further explored through a numerical assessment, and self-similar solutions are constructed to determine the evolution of the flame front in terms of the temperature and pressure variables.
Robust unenhanced peripheral magnetic resonance angiography using single-slab 3D chemical-shift-encoded GRASE
Authors: Maeng Hyunkyung , Kim Hahnsung , Sohn Jeong-Woo , Park Jaeseok 
Published: August 2023

Abstract

Objective. To develop a novel, unenhanced magnetic resonance angiography (MRA) exploiting cardiac-gated, single-slab 3D chemical-shift-encoded gradient- and spin-echo (GRASE) imaging for robust background suppression. Approach. The proposed single-slab 3D GRASE employs variable-flip-angles (VFA) in the refocusing radio-frequency (RF) pulse train to promote sensitivity to blood flow as well as imaging encoding efficiency. Phase encoding blips are inserted between adjacent lobes of the switching readout gradients such that chemical shift-induced phase information is encoded into different locations in k-space. Based on the assumption that most background signals in the angiogram come from the fatty tissues, the proposed method directly separates angiograms from fatty background tissue signals from highly incomplete measurements by solving a constrained optimization problem with sparsity prior. Numerical simulations and experiments were performed to validate the effectiveness of the proposed method in healthy volunteers as compared with conventional fresh blood imaging (FBI). Main results. Compared with conventional FBI, the proposed method yields clearer delineation of small branching arteries and robust fatty background suppression without apparent loss of signals. Significance. We have successfully demonstrated the feasibility of the proposed, single-slab 3D VFA GRASE with chemical-shift-encoded reconstruction for the generation of robust unenhanced peripheral MRA.
MUE-CoT: multi-scale uncertainty entropy-aware co-training framework for left atrial segmentation
Authors: Hao Dechen , Li Hualing , Zhang Yonglai , Zhang Qi 
Published: August 2023

Abstract

Objective. Accurate left atrial segmentation is the basis of the recognition and clinical analysis of atrial fibrillation. Supervised learning has achieved some competitive segmentation results, but the high annotation cost often limits its performance. Semi-supervised learning is implemented from limited labeled data and a large amount of unlabeled data and shows good potential in solving practical medical problems. Approach. In this study, we proposed a collaborative training framework for multi-scale uncertain entropy perception (MUE-CoT) and achieved efficient left atrial segmentation from a small amount of labeled data. Based on the pyramid feature network, learning is implemented from unlabeled data by minimizing the pyramid prediction difference. In addition, novel loss constraints are proposed for co-training in the study. The diversity loss is defined as a soft constraint so as to accelerate the convergence and a novel multi-scale uncertainty entropy calculation method and a consistency regularization term are proposed to measure the consistency between prediction results. The quality of pseudo-labels cannot be guaranteed in the pre-training period, so a confidence-dependent empirical Gaussian function is proposed to weight the pseudo-supervised loss. Main results. The experimental results of a publicly available dataset and an in-house clinical dataset proved that our method outperformed existing semi-supervised methods. For the two datasets with a labeled ratio of 5%, the Dice similarity coefficient scores were 84.94% ± 4.31 and 81.24% ± 2.4, the HD95 values were 4.63 mm ± 2.13 and 3.94 mm ± 2.72, and the Jaccard similarity coefficient scores were 74.00% ± 6.20 and 68.49% ± 3.39, respectively. Significance. The proposed model effectively addresses the challenges of limited data samples and high costs associated with manual annotation in the medical field, leading to enhanced segmentation accuracy.
Multi-level spatial-temporal and attentional information deep fusion network for retinal vessel segmentation
Authors: Huang Yi , Deng Tao 
Published: August 2023

Abstract

Objective. Automatic segmentation of fundus vessels has the potential to enhance the judgment ability of intelligent disease diagnosis systems. Even though various methods have been proposed, it is still a demanding task to accurately segment the fundus vessels. The purpose of our study is to develop a robust and effective method to segment the vessels in human color retinal fundus images. Approach. We present a novel multi-level spatial-temporal and attentional information deep fusion network for the segmentation of retinal vessels, called MSAFNet, which enhances segmentation performance and robustness. Our method utilizes the multi-level spatial-temporal encoding module to obtain spatial-temporal information and the Self-Attention module to capture feature correlations in different levels of our network. Based on the encoder and decoder structure, we combine these features to get the final segmentation results. Main results. Through abundant experiments on four public datasets, our method achieves preferable performance compared with other SOTA retinal vessel segmentation methods. Our Accuracy and Area Under Curve achieve the highest scores of 96.96%, 96.57%, 96.48% and 98.78%, 98.54%, 98.27% on DRIVE, CHASE_DB1, and HRF datasets. Our Specificity achieves the highest score of 98.58% and 99.08% on DRIVE and STARE datasets. Significance. The experimental results demonstrate that our method has strong learning and representation capabilities and can accurately detect retinal blood vessels, thereby serving as a potential tool for assisting in diagnosis.
Atmospheric pressure plasma treatment of skin: penetration into hair follicles
Authors: Konina Kseniia , Freeman Theresa A , Kushner Mark J 
Published: August 2023

Abstract
Sterilization of skin prior to surgery is challenged by the reservoir of bacteria that resides in hair follicles. Atmospheric pressure plasma jets (APPJs) have been proposed as a method to treat and deactivate these bacteria as atmospheric plasmas are able to penetrate into structures and crevices with dimensions similar to those found in hair follicles. In this paper, we discuss results from a computational investigation of an APPJ sustained in helium flowing into ambient air, and incident onto a layered dielectric similar to human skin in which there are idealized hair follicles. We found that, depending on the location of the follicle, the bulk ionization wave (IW) incident onto the skin, or the surface IW on the skin, are able to launch IWs into the follicle. The uniformity of treatment of the follicle depends on the location of the first entry of the plasma into the follicle on the top of the skin. Typically, only one side of the follicle is treated on for a given plasma pulse, with uniform treatment resulting from rastering the plasma jet across the follicle over many pulses. Plasma treatment of the follicle is sensitive to the angle of the follicle with respect to the skin, width of the follicle pocket, conductivity of the dermis and thickness of the underlying subcutaneous fat layer, the latter due to the change in capacitance of the tissue.
A novel coarse-grained modeling and simulation for the microstructure evolution of ferrofluids
Authors: Zhao Penghui , Du Tianxiang , Zeng Yaoxiang , Pan Zhongwen , Ma Ning , Zhao Jiamin , Dong Xufeng 
Published: August 2023

Abstract
Ferrofluid (FF) has attracted more and more attention due to its tunable rheological properties, in which the microstructure under a magnetic field plays an important role in these properties. In this study, an innovative coarse-grained (CG) model of FF is presented for the first time to capture the microstructure evolution of FF at the nanoscale. The potential functions of carrier liquid for FF CG models are obtained by the iterative Boltzmann inversion method, and the CG nonbonded interaction between the magnetic particles (MPs) is obtained via the strain energy conservation. Then, CG molecular dynamics (CGMD) simulations are used to study the microstructure evolutions of FF under different magnetic fields. Notably, we demonstrate the existence of a carrier liquid adsorption layer on the MPs surface, and its thickness is calculated. The staggered arrangement style of MPs in the chains is also revealed by the CGMD method. The present FF CG model has fully considered the carrier liquid molecular structure and interaction with the MPs, and the CGMD is used to solve the problem that classical molecular dynamics cannot simulate the microstructure of FF, making the simulation results more in line with the actual situation.
Effects of recycling on polystyrene shape memory polymers for in-situ resource utilization
Authors: Nelson Maggie A , Siwakoti Midhan , Cardon Rylee , Triggs Eldon , Mailen Russell W 
Published: August 2023

Abstract
One-way, thermoplastic shape memory polymers (SMPs) used as actuators for self-folding origami are typically single-use materials that would be decommissioned upon completion of mission objectives. As a result, there exists an abundance of unutilized, single-use SMP waste. In-situ resource utilization (ISRU) and recycling offer solutions for the use and integration of sustainable SMP material infrastructures on Earth and for long-duration space missions. Unfortunately, mechanical recycling causes degradation of material properties. Therefore, it is imperative to quantify the effects of recycling on SMP properties. Herein, we utilize a thermo-mechanical recycling method applied to polystyrene SMPs. After recycling, we conduct Fourier transform infrared spectroscopy, differential scanning calorimetry, and dynamic mechanical analysis to investigate changes to the chemical structure, viscoelastic properties, and shape recovery response of the polymer. The results indicate negligible changes to the viscoelastic and shape recovery properties of the recycled material from one to six recycling sequences (extrusions) when compared to the non-recycled material. The most evident form of deterioration occurred in the physical appearance of the material. Otherwise, the shape recovery performance and thermo-mechanical properties remained consistent after recycling. Therefore, the recovery characteristics (recovery ratio, recovery time, and actuation stress) do not change significantly after six recycling sequences, making this material viable for ISRU applications in space environments.
Adiabatic quantum-flux-parametron boosters for long interconnection and large fanouts
Authors: Mizushima Naoya , Takeuchi Naoki , Yamanashi Yuki , Yoshikawa Nobuyuki 
Published: August 2023

Abstract
Adiabatic quantum flux parametron (AQFP) is energy-efficient superconducting logic that operates with zero static energy consumption and extremely small dynamic energy consumption thanks to the adiabatic switching of the logic gates. One drawback in AQFP logic circuits is the wire length and fan-out limitations because of the low driving ability of the logic gates, which results in a large circuit area and significant latency. In the present study, we propose AQFP boosters with high driving ability. Two types of AQFP boosters are proposed: one is composed of a parallel connection of AQFP buffers, and the other uses multistage buffers driven by one excitation clock. We evaluated the maximum wire length of the proposed boosters by circuit simulations, including thermal noises, and found that the maximum wire length is 3.9 mm for fan-out one and 1 mm for fan-out four. We implemented the boosters and demonstrated their correct operations at low-speed tests. We also demonstrated a 5-to-31 decoder using the proposed boosters. It was shown that the circuit area, latency, and energy consumption were improved by about 30% compared to the design without the boosters.
E–I characteristics and critical currents of small Bi-2223/Ag coil thermally stabilized by solid and liquid nitrogen compared to water ice
Authors: Búran M , Kopera L , Melišek T , Kováč P 
Published: August 2023

Abstract
A small-sized coil of helically wound Bi-2223/Ag tape was measured in liquid/solid nitrogen (LN2/SN2), and also in water (H2O) ice at external fields of 0–8 T and in a temperature range of 10–77 K. This work is especially focused on the coil stability for current amplitudes above the critical current criterion of 1 µV cm−1. While the E–I characteristics measured under the critical current criterion did not show any substantial variances at these different cooling conditions, significant differences were observed above the critical current magnitude, mainly upon cooling by solid nitrogen and water ice. The results confirm improved thermal stability for the coil measured in sub-cooled water ice compared to solid nitrogen. Consequently, cooling by water ice could be interesting for future applications of high-temperature superconducting coils.
Novel two-step procedure for measuring I
c vs. tensile stress of commercial REBCO tape
Authors: Zhang Zili , Chen Sikan , Wang Lei , Liu Hui , Liu Yan , Zhao Yue , Suo Hongli , Wang Qiuliang 
Published: August 2023

Abstract
This paper presents a novel two-step procedure for measuring the critical current (I
c) properties as a function of tensile stress. The proposed method completely eliminates the possible negative effect of the voltage tap used during the tensile procedure, allowing the actual I
c irreversible degradation stress to be clearly determined. Six different commercial REBCO tapes from five manufacturers were tested. The I
c value does not degrade until the stress reaches the ‘inflection area’ in the tensile curve, which corresponds to the most pronounced transformation step from elastic to plastic deformation. This allows easy estimation of the stress corresponding to I
c irreversible degradation by a simple and accurate cryogenic tensile curve instead of complicated in-situ I
c tensile measurement. A feasible composite-material tensile model is established to explain the phenomenon. In addition, fatigue measurements on a commercial REBCO tape from Shanghai Superconductor technology show that the tape can withstand 10 000 cycles under 580 MPa and over 5000 cycles under 695 MPa, which also is consistent with the proposed composite-materials tensile model and is confirmed by the EBSD experiments on the Hastelloy substrate. This research provides better insight and tools for designing and fabricating extremely high-field magnets.
Nonlinear optical and luminescence studies on Zinc Alumino-Boro-Silicate glasses co-doped with Dy3+ and Sm3+ ions for optical limiting and W-LEDs applications
Authors: Monisha M , Rajput Vinod K , Naraharisetty Sri Ram G , Sayyed M I , Altowyan Abeer S , Kamath Sudha D 
Published: August 2023

Abstract
In the present work, Dy3+ and Sm3+ co-doped Zinc Alumino-Boro-Silicate (ZABS) glasses doped with an optimized Dy3+ concentration (0.5 mol%) and varying Sm3+ concentrations are prepared using a conventional melt-quenching method. Optical absorption spectra showed the signature of Dy3+ and Sm3+ peaks through possible transitions in the range of 300–1800 nm. The optical bandgap of the glasses is obtained in the range of 4.2 to 3.9 eV. The emission curves aswellas decay lifetimes of Dy3+ and Sm3+ ions under 350 nm and 402 nm excitation were investigated using photoluminescence studies. Through the Inokuti-Hirayama (I-H) energy fitting model, the nature of energy transfer between Dy3+ and Sm3+ is found to be a ‘dipole–dipole’ type. Neutral to near warm white light emissions from the co-doped glasses were evaluated through colour chromaticity and correlated colour temperature calculations. The nonlinear optical measurements showed the reverse saturable absorption behaviour of the glasses whose nonlinear absorption coefficients (β) decreased with higher concentrations of Sm3+. Among the prepared glasses, ZABSDS1 (Sm3+ 0.1 mol%) glass showed the highest nonlinear coefficient (3.56 × 10−12 W cm−2) and lowest optical limiting (37.5 × 1011 W cm−2) threshold. From the overall studies, the suitability of the prepared glasses for White LEDs and optical limiting laser device applications were realized.