bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of thermocompression on properties of transparent glass-ceramics containing quantum dots
Authors: Tao Yiting , Wang Panting , Wu Ting , Zhao Mingjun , Chen Danping
Published: September 2023

A novel strategy for preparing transparent glass-ceramics with a uniform quantum-dot size and high transparency via thermocompression is reported. Borophosphate glass containing the Cs–Pb–Br component is prepared using the conventional melting method. The glass is then pressed with a piece of stainless steel to generate thermocompression during the crystallization heat treatment, by which small and uniform-sized nanocrystals of CsPbBr3 quantum dots are produced in glass. Thermocompression reduces the specific surface energy of the nanocrystals and inhibits the abnormal growth of microcrystals, thereby reducing the average particle size from 7 to 4 nm and completing the growth of microcrystals. This significantly increases the transmittance of the glass-ceramics and enhances the luminescence intensity by approximately threefold. The experimental results show that low-intensity pressure can control the structure and properties of glass-ceramics during the growth of microcrystals in glass, which is a new process for preparing transparent microcrystalline glass.
Bloch point nanospheres for the design of magnetic traps
Authors: Tejo F. , Zambrano-Rabanal C. , Carvalho-Santos V. L. , Vidal-Silva N.
Published: September 2023

Through micromagnetic simulations, this work analyzes the possibility of using an array of magnetic nanospheres hosting Bloch points (BPs) to compose a system with the features of a magnetic trap (MT). We show that a BP can be nucleated as a metastable configuration in a wide range of the nanosphere radius compared to a quasi-uniform and vortex state. We also show that the stabilized BP generates a quadrupolar magnetic field outside the nanosphere. Based on this fact, we analyze the field profile of different arrays of these nanospheres, showing that the obtained magnetic field profiles share the needed features to compose MTs. Some highlights of using an array of Bloch point nanospheres in MTs rely on the magnetic field gradients achieved, which are orders of magnitude higher than similar standard systems, and allow three-dimensional trapping. Our results could be useful in trapping particles through the intrinsic magnetization of ferromagnetic nanoparticles while avoiding the commonly used mechanisms associated with Joule heating.
Hybrid-wave solutions for a (2 + 1)-dimensional variable-coefficient Kadomtsev-Petviashvili equation in fluid mechanics and plasma physics
Authors: Zhao Yu , Tian Bo
Published: September 2023

In this paper, a (2 + 1)-dimensional variable-coefficient Kadomtsev-Petviashvili equation in fluid mechanics and plasma physics is studied. Gram-type solutions are derived via the bilinear Kadomtsev-Petviashvili hierarchy reduction method. Taking different parameter conditions in the Gram-type solutions, we construct the Y-shaped breather solutions and two types of the hybrid-wave solutions. Asymptotic forms for the aforementioned solutions are given. Based on the asymptotic forms, influences of the variable coefficients on the interactions of the breathers and solitons are studied. We obtain three types of the hybrid-wave solutions, which consist of several breathers and solitons. When those breathers and solitons interact, they form the evolving polyhedral arrangement. Changes of the entire arrangement of the breathers and solitons, and the processes of fission or fusion, are discussed and presented.
Simulation calculation of electric field distribution in the rat brain irradiated by electromagnetic pulses
Authors: Wang Shan , Song Zhongguo , Kang Jianjun , Guo Guozhen
Published: September 2023

Based on the spectrum distribution of electromagnetic pulses (EMPs), we constructed a dispersive electromagnetic model of rats with a fine division of tissues and organs and calculated the internal electric field distribution in the rat brain exposed to EMPs. The results showed that EMP radiation was capable of generating electric field distribution with good uniformity in the rat brain and that the peak field intensity in the rat brain was about 1/250 of that in the spatial domain. The electric field in the cerebral cortex was slightly higher than that in the deep hippocampus, striatum, and thalamus, and it was probably the lowest in the hypothalamus. In the cortex, the electric field was low in the prefrontal cortex, while it was relatively high in the parietal and temporal lobes near the middle and at the back of the brain. The data provide a theoretical quantitative basis for establishment of the dose–effect relationship between the electric field in the rat brain and biological effects of the pulse. In addition, it serves as a reference for simulation calculation of the effect of EMPs in living organisms.
Plasma flows during the ablation stage of an over-massed pulsed-power-driven exploding planar wire array
Authors: Datta R. , Angel J. , Greenly J. B. , Bland S. N. , Chittenden J. P. , Lavine E. S. , Potter W. M. , Robinson D. , Varnish T. W. O. , Wong E. , Hammer D. A. , Kusse B. R. , Hare J. D.
Published: September 2023

We characterize the plasma flows generated during the ablation stage of an over-massed exploding planar wire array, fielded on the COBRA pulsed-power facility (1 MA peak current, 250 ns rise time). The planar wire array is designed to provide a driving magnetic field (80–100 T) and current per wire distribution (about 60 kA), similar to that in a 10 MA cylindrical exploding wire array fielded on the Z machine. Over-massing the arrays enables continuous plasma ablation over the duration of the experiment without implosion. The requirement to over-mass on the Z machine necessitates wires with diameters of 75–100μm, which are thicker than wires usually fielded on wire array experiments. To test ablation with thicker wires, we perform a parametric study by varying the initial wire diameter between 33 and 100 μm. The largest wire diameter (100 μm) array exhibits early closure of the cathode-wire gap, while the gap remains open over the duration of the experiment for wire diameters between 33 and 75 μm. Laser plasma interferometry and time-gated extreme-ultraviolet (XUV) imaging are used to probe the plasma flows ablating from the wires. The plasma flows from the wires converge to generate a pinch, which appears as a fast-moving (V≈100kms−1) column of increased plasma density (n¯e≈2×1018cm−3) and strong XUV emission. Finally, we compare the results with three-dimensional resistive-magnetohydrodynamic (MHD) simulations performed using the code GORGON, the results of which reproduce the dynamics of the experiment reasonably well.
Effect of the density ratio on the oscillatory Saffman–Taylor instability in vertical conical Hele–Shaw cell
Authors: Subbotin Stanislav , Karpunin Ivan , Kurysheva Darya , Kozlov Victor
Published: September 2023

The stability of an oscillating interface between two immiscible liquids with a high viscosity contrast in an axisymmetric conical Hele–Shaw cell in dependence on the density ratio is studied experimentally. The symmetry axis of the cell is vertical, while the tangential component of the gravy acts on the axisymmetric interface. The contact line is almost motionless, while the low-viscosity liquid penetrates a high-viscosity one in the form of an axisymmetric “tongue” in the course of an oscillating cycle. The increase in the oscillation amplitude leads to the development of azimuthal patterns (fingers) at the interface. Fingers of a low-viscosity liquid appear when a viscous liquid is being squeezed out of the cell and reach their maximum length at the maximum displacement of the interface. Then, the fingers decrease and are replaced by small depressions penetrating into the low-viscosity liquid in the phase of maximum boundary displacement toward the low-viscosity liquid. The increase in the density ratio of liquids has a stabilizing effect on the interface: The instability threshold is shifted to the higher oscillation amplitudes. Also, the stability threshold is independent of whether the high-viscosity or low-viscosity liquid is denser than the other one. We propose a new dimensionless parameter that controls the stability of the interface—the multiplication of the square root of the capillary number and the dimensionless amplitude of interface oscillations. It is revealed that the critical value of the stability parameter increases linearly with an increase in the density ratio of liquids.
Numerical analysis of voltage-controlled magnetization switching operation in magnetic-topological-insulator-based devices
Authors: Komine Takashi , Chiba Takahiro
Published: September 2023

We theoretically investigate influences of electronic circuit delay, noise, and temperature on write-error-rate (WER) in voltage-controlled magnetization switching operation of a magnetic-topological-insulator-based device by means of the micromagnetic simulation. This device realizes magnetization switching via spin–orbit torque (SOT) and voltage-controlled magnetic anisotropy (VCMA), which originate from the 2D-Dirac electronic structure. We reveal that the device operation is extremely robust against circuit delay and signal-to-noise ratio. We demonstrate that the WER on the order of ∼10−4 or below is achieved around room temperature due to steep change in VCMA. Also, we show that the larger SOT improves thermal stability factor. This study provides a next perspective for developing voltage-driven spintronic devices with ultra-low power consumption.
On the flow unsteadiness and operational characteristics of a novel supersonic fluidic oscillator
Authors: Maikap Spandan , Karthick S. K. , Rajagopal Arun Kumar
Published: September 2023

A novel supersonic jet oscillating method is investigated both experimentally and numerically. A rectangular primary supersonic jet is issued into a confined chamber with sudden enlargement. Secondary control jets are issued from the top and bottom backward-facing step regions formed due to sudden enlargement. The primary jet is oscillated in the transverse direction by blowing the secondary jets in the streamwise direction in a pulsating manner with a phase shift. The out-of-phase secondary jet blowing causes the primary jet to periodically adhere to the upper and lower part of the confined chamber, causing flapping of the primary jet and acting as a supersonic fluidic oscillator. The supersonic jet oscillation characteristics are experimentally investigated using shadowgraph type flow visualization technique and steady and unsteady pressure measurements. Quantitative analysis of the shadowgraph images using the construction of y – t and y – f plots reveals the presence of periodic jet oscillation with a discrete dominant frequency similar to the secondary jet excitation frequency. The existence of linearity between the excitation frequency and the flapping jet frequency on the low-frequency (0.66–6.6 Hz) side is first proven experimentally. Later, the high-frequency (16.67–5000 Hz) operation extent of the supersonic fluidic oscillator is further demonstrated using unsteady computational studies owing to the existing experimental facility's limitations. A reduced-order analytical framework has also been proposed to investigate the limiting oscillation frequency. It is found that the limiting frequency predicted from the proposed analytical model shows fairly good agreement with the computationally predicted results (5 kHz).
SPARC as a platform to advance tokamak science
Authors: Creely A. J. , Brunner D. , Mumgaard R. T. , Reinke M. L. , Segal M. , Sorbom B. N. , Greenwald M. J.
Published: September 2023

The unique capabilities of the SPARC tokamak mean that it has the potential to contribute significantly to tokamak science and plasma physics, motivating further collaboration and broader data access beyond the CFS and MIT teams. SPARC is a compact, high-field tokamak that is currently under construction and is predicted to achieve burning plasma conditions once in operation. SPARC experimental data has the potential to advance the understanding of many aspects of tokamak physics, including but not limited to confinement and stability at high field and high density, burning plasma physics, disruption physics, and boundary physics and heat flux management in power plant-relevant conditions. The SPARC team is already a combination of members from Commonwealth Fusion Systems (CFS), a privately funded company, and the Massachusetts Institute of Technology (MIT), a non-profit university. This article describes the opportunities for the SPARC team to work with other researchers to advance toward a fusion power plant on the fastest possible time scales and to simultaneously broaden scientific understanding of plasma physics, meeting the missions of both CFS and academic partners.
Predicting abrasion resistance of concrete containing plastic waste, fly ash, and graphene nanoplatelets using an artificial neural network and response surface methodology
Authors: Adamu Musa , Rehman Khalil Ur , Ibrahim Yasser E. , Shatanawi Wasfi
Published: September 2023

The influence of plastic waste (PW) and fly ash as partial substitutes to coarse aggregate and cement, respectively, and Graphene NanoPlatelets (GNPs) as additive to cement mass on the Cantabro abrasion loss of concrete was investigated in this study. Artificial Neural Network (ANN) and Response Surface Methodology (RSM) techniques were adopted to establish models for estimating the Cantabro loss of the concrete. The variables used were PW, fly ash, GNPs, water-to-cementitious material ratio, and number of revolutions. For the ANN, 60 unique samples of Cantabro loss (%) were used. Fourteen neurons are considered in the hidden layer, and the Levenberg–Marquardt technique is applied to train the network. Both the coefficient of determination (R) and mean square error were taken into consideration for the performance analysis of ANN models to predict the Cantabro loss (%). The present prediction of Cantabro loss (%) by use of the ANN can be a helping source for preceding studies on proposing the solution to utilize PW in concrete. The developed model using RSM also has a very high degree of correlation (R2 = 0.953) and was highly significant. However, in terms of accuracy of prediction, the ANN model was the best, having the highest coefficient of determination with R2 values of 0.995, 0.995, and 0.992 for training, validation, and testing, respectively.
Discharge characterization and altitude correction of shielding sphere-plate gap at an altitude of 3400 m
Authors: Xiao Wei , Luo Bing , Liu Lei , Zhong Zheng , Zhang Hang , Ma Wenchuang , Cheng Yuzhou , Li Tianjiao , Lin Guo , Fan Caijin , Zhang Haofeng , Wang Ping , Liu Yunpeng , Geng Jianghai
Published: September 2023

Southeast Tibet in China is rich in clean energy such as water energy, light energy, and wind energy. As the key means of large-scale clean energy transmission in southeast Tibet, the ultra-high voltage (UHV) power transmission projects will be constructed at an altitude of nearly 4000 m. To accurately acquire the external insulation strength of electrical equipment operating at different altitudes, the standard positive switching impulse voltages were applied to a rod electrode and a 1.1 m diameter shielding sphere at the altitude of 3400, 2100, and 80 m. The switching impulse discharge characterization and altitude correction factors of the 1.1 m diameter shielding sphere-plate gap under different clearances at different altitudes were obtained. The discharge voltage of the rod-plate gap at the altitude of 80 m was corrected to the altitude of 3400 m using altitude correction methods recommended by GB 311.1, GB/T 16927.1, and DL/T 2305. Further comparison was made between the calculation results using the three altitude correction methods mentioned above and the test results at an altitude of 3400 m. The discharge characterization and the minimum clearance of the end fittings of the electrical equipment in the valve hall at the altitude of 3800 and 4500 m were obtained by fitting and extrapolating the test data. The research results provide important reference significance for the external insulation configuration of UHV converter stations constructed in areas with an altitude of 3000 m and above.
Active electromagnetic absorption metasurface with a switchable reflection band
Authors: Guo Qingxin , Chen Qian , Su Jianxun , Li Zengrui
Published: September 2023

An active electromagnetic (EM) absorption metasurface is proposed to achieve a switchable reflection band between two absorption bands. The metasurface consists of one lossy layer and one active layer separated by an air gap. The top lossy layer is composed of periodic metallic unit cells, designed to absorb the incident EM wave at the lower and higher absorption bands. PIN diodes are embedded on the bottom periodic array to control the reflection coefficient. When the PIN diodes are turned off, the incident EM wave is absorbed at lower and higher bands while reflected at the intermediate band; when the PIN diodes are turned on, the reflection band is switched off and a wide absorption band is achieved. Experimental results verify the numerical simulations.
The exceptional point of PT-symmetry metasurface: Topological phase studies and highly sensitive refractive index sensing applications
Authors: Gao Fan , Liu Hao , Zhou Jian , Deng Juan , Yan Bo
Published: September 2023

Exceptional points (EPs) are critical phase points in non-Hermitian systems, exhibiting fantastic physical phenomena and plenty of applications, such as unidirectional reflectionless and ultrahigh-sensitive detection of perturbations. Here, a non-Hermitian metasurface based on multilayers split-ring resonators (SRRs) is proposed with specific EP effects. By changing the angle of the SRRs and adjusting the geometric parameters of the metasurface, EPs are generated with topologically protected 2π-phase accumulation. A unique EP effect can be achieved in the THz region, and high-performance sensing of environment refractive index can be realized around the EP position. Therefore, this work demonstrates an EP-based sensing enhancement at non-Hermitian systems compared to Hermitian ones and paves the way for the design of high-performance THz sensors based on topological polaritonic effects.
Effect of acoustic metasurface on hypersonic-boundary-layer wave packet
Authors: Guo Peixu , Liu Xiao , Zhao Rui , Hao Jiaao , Wen Chih-Yung
Published: September 2023

Effect of the acoustic metasurface on a broadband wave packet in a Mach 6 boundary layer is studied. Direct numerical simulations (DNSs) with time-domain impedance boundary condition (TDIBC) and metasurface with microstructures are performed. It is shown that DNS with TDIBC resolves the amplitude and phase information of the wave packet satisfactorily. The minor prediction discrepancy arises from the modeling error in the acoustic impedance. The interesting finding of this paper is that the metasurface behaves as an equivalent unsteady blowing-suction model to perturb the wall-normal velocity and then passively the pressure field. Although both pressure and wall-normal velocity appear in the characteristic-wave variable, the pressure can be decoupled to be updated by the Neumann condition, as usually employed in Navier–Stokes solvers. The dominant frequency scale that enables reproducing the stabilization effect of the metasurface is found to be slightly smaller than the energetic frequency maximum of the wave packet. This observation indicates that the high-frequency unsteadiness nature of the blowing-suction behavior is indispensable, which is induced by the interaction of the metasurface and the wave packet. For the stabilization mechanism, energy analysis reveals that a dilatation-related work near the wall is significantly suppressed by the metasurface, which agrees with the wall-normal location where the wave-packet fluctuation gets attenuated.
Ion-based double network hydrogel with compressive, conductive, and sensing properties for sports monitoring
Authors: Yang Zhi , Xiao Ya
Published: September 2023

Conductive hydrogel, as a promising candidate material, is ideal for multifunctional strain sensors due to its similarity to biological tissues. It offers good wearability and high-precision information acquisition. However, fabricating conductive hydrogel-based strain sensors with both superior mechanical and conductive properties remains challenging. In this study, a compressive and conductive strain sensor based on multi-dynamic interactions is fabricated through a simple strategy. The strategy exploits hydrogen bonding and ionic ligand bonding by using nanocellulose reinforced poly(acrylic acid) hydrogels impregnated with the Fe3+ solution to prepare a double-network hydrogel. The prepared PAA/CNF–Fe3+ double-network hydrogel exhibited excellent properties, including extraordinary performance compressive stress (2.96 MPa) and remarkable electrical conductivity (6.34 S/m). With these advantages, the PAA/CNF–Fe3+ double network hydrogel was developed to be an attractive strain flexible sensor with cyclic stability (150 cycles) and good strain sensitivity (GF = 2.87). In addition, the PAA/CNF–Fe3+ hydrogel flexible sensor can be used as an electronic skin to accurately discriminate subtle and large body movements. Given the simple strategy, double network structure, and satisfactory functionality, the PAA/CNF–Fe3+ hydrogel provides a new sustainable and multifunctional development strategy that can be applied in the field of strain sensors and medical detection.
Optimization design of electrode structure of GaAs photoconductive semiconductor switch
Authors: Wang Hongqi , Tian Liqiang , Shi Wei , Ma Cheng , Wu Meilin , Chen Kaipeng
Published: September 2023

Previous studies revealed that changing the electrode structures of a gallium arsenide photoconductive semiconductor switch (GaAs PCSS) can significantly affect the local electric field and current density at the electrodes. Knowing the optimization of the electrode structures of GaAs PCSS can improve the withstand voltage performance and current carrying capability. In this work, we optimize the surface contact electrode structure of GaAs PCSS, and numerical simulations are performed to systematically study the electric field and current density distribution in the bulk of the device. The result shows that the maximum transverse current density and maximum longitudinal current density of the embedded 172° isosceles trapezoid electrode structure are smaller than other kinds of electrode structures, which is the most favorable for improving the withstand voltage and current carrying capability of GaAs PCSS.
History and fundamentals of molecular photochromism
Authors: Jago David , Gaschk Emma E. , Koutsantonis George A.
Published: September 2023

Photochromic molecules reversibly change their colour upon exposure to light. The increasing need for smart materials in the real world, coupled with progress in synthetic chemistry, fast spectroscopic techniques, and theoretical power in research laboratories, have seen research in organic photochromism accelerate over the past few decades. In this Primer Review, the topic of organic photochromism is introduced. The fundamental concepts and histories are given to contextualise this field. Moreover, key photochromic molecules and selected applications are showcased to provide the interested reader with an entry to this fascinating field of science and emerging technology.
Microstructures and properties of ultrasonically surface-modified Cu–0.2Be–1.0Co alloy
Authors: Wang Jinyun , Zhang Bowen , Hong Zhenyu , Zhao Hongliang
Published: September 2023

Low-Be copper alloys exhibit high thermal and electrical conductivities but weak strength, hardness, wear and corrosion resistances, which limit their practical applications severely. To overcome these defects, we herein systematically investigate the effects of ultrasonic surface modification on the microstructures and properties of Cu–0.2Be–1.0Co alloy. It is found that the gradient microstructures characterized by pile-ups and dents, fine grains, dense dislocations and compressive residual stresses are generated in the 171 μm thickness surface layer of the Cu–0.2Be–1.0Co alloy by ultrasonic surface modification. As a result, the surface hardness obtains a 162% enhancement, the wear rate drops from 5.03 × 10−4 to 3.46 × 10−4 mm3·N−1·m−1, and the electrochemical corrosion current density decreases from 3.24 to 1.92 μA/cm2. These results indicate that the comprehensive properties of Cu–0.2Be–1.0Co alloy can be simultaneously improved by utilizing ultrasonic surface modification.
Completing the Cabrera Circle: deriving adaptable leads from ECG limb leads by combining constraints with a correction factor
Authors: Dathe Henning , Krefting Dagmar , Spicher Nicolai
Published: September 2023

Objective. We present a concept for processing 6-lead electrocardiography (ECG) signals which can be applied to various use cases in quantitative electrocardiography. Approach. Our work builds upon the mathematics of the well-known Cabrera sequence which is a re-sorting of the six limb leads (I, II, III, aV
R, aV
L, aV
F) into a clockwise and physiologically-interpretable order. By deriving correction factors for harmonizing lead strengths and choosing an appropriate basis for the leads, we extend this concept towards what we call the ‘Cabrera Circle’ based on a mathematically sound foundation. Main results. To demonstrate the practical effectiveness and relevance of this concept, we analyze its suitability for deriving interpolated leads between the six limb leads and a ‘radial’ lead which both can be useful for specific use cases. We focus on the use cases of i) determination of the electrical heart axis by proposing a novel interactive tool for reconstructing the heart’s vector loop and ii) improving accuracy in time of automatic R-wave detection and T-wave delineation in 6-lead ECG. For the first use case, we derive an equation which allows projections of the 2-dimensional vector loops to arbitrary angles of the Cabrera Circle. For the second use case, we apply several state-of-the-art algorithms to a freely-available 12-lead dataset (Lobachevsky University Database). Out-of-the-box results show that the derived radial lead outperforms the other limb leads (I, II, III, aV
R, aV
L, aV
F) by improving F1 scores of R-peak and T-peak detection by 0.61 and 2.12, respectively. Results of on- and offset computations are also improved but on a smaller scale. Significance. In summary, the Cabrera Circle offers a methodology that might be useful for quantitative electrocardiography of the 6-lead subsystem—especially in the digital age.
Collective dynamics of a dense streamer front
Authors: Teixeira-Gomes M B , Gordillo-Vázquez F J , Luque A
Published: September 2023

We explore the dynamics of dense streamer channel fronts. We introduce a novel, fully three-dimensional, adaptive mesh refinement streamer simulation code, which leverages the power of general-purpose graphical processing units to accelerate computations. Our code enables the simulation of systems comprising several parallel-propagating streamers, using appropriate boundary conditions to emulate an infinitely extended front of positive streamers in ambient air. Our findings reveal that denser streamer packings result in slower front propagation and increased electric field screening within the streamers. To interpret these results and progress towards developing a coarse-grained corona model, we present a streamlined model that effectively approximates the behavior of the comprehensive microscopic system.
Selective removal of 4H-SiC porous structures caused by photoelectric chemical etching via post oxidation annealing
Authors: Li Yunkai , Zhao Siqi , Yang Shangyu , Guo Ning , Yuan Weilong , Pei Yicheng , Yan Guoguo , Liu Xingfang
Published: September 2023

Low-temperature post oxidation annealing of 4H-SiC at 900 °C for 90 min after photoelectric chemical (PEC) etching in alkaline solution can eliminate the porous structures that form during the etching process, reduce the porosity, and optimize the surface morphology, which has minimal effect on unetched surfaces, allowing for selective treatment between etched and unetched surfaces. Additionally, it can improve the etching depth and enable effective repetition of the etching process. These benefits make PEC etching a valuable technique for microstructure fabrication and surface treatment.
Overview of spark plasma synthesis and sintering of MgB2 superconductor
Authors: Xing Y , Bernstein P , Muralidhar M , Noudem J
Published: September 2023

This study aims to investigate the sintering mechanisms of magnesium diborides using spark plasma sintering and optimize the sintering process conditions. Three different precursor materials were used: (i) commercial powder MgB2, (ii) mixtures of magnesium and nano boron powder (Mg + 2B), and (iii) mixtures of Mg and MgB4 powder for an ‘in-situ’ reactive synthesis. The density of the obtained bulks exceeds 90% of the theoretical density of the material. The structure and microstructure of the samples were analyzed using x-ray diffraction and scanning electron microscope, which were correlated with their superconducting properties. The critical current density (J
c), pinning force (f
p), and electrical resistivity (ρ) of the samples were also investigated. The results show that the in-situ reactive synthesis of MgB2 using magnesium and nano boron powder was the most effective method for producing high-quality samples with improved superconducting properties. The findings could lead to the development of more efficient methods for producing high-performance of MgB2 bulks.
The research on the influence mechanism of internal deformation for the performance of Bi-2212
Authors: Zhang Zhen-Chuang , Yang Dong-Sheng , Yu Min , Zhou Meng-Liang , Zhou Hai-Shan , Qin Jing-Gang
Published: September 2023

Cable-in-conduit conductor (CICC), one of the most promising conductors for manufacturing magnets in magnetic confinement fusion devices, has attracted lots of attention. In the production of CICC, porosity control is necessary for its stability. The porosity control is usually realized by the diameter-reducing process, which would also lead to indentation damages to the elements of CICC-superconducting wires. In this article, systematic research of indentation damages was carried out on the next generation of high-temperature superconducting materials–Bi-2212 wires. The results indicate that the current carrying capacity of the indentation-damaged wire would first keep steady and then show exponential decline with the increase of indentation depth. The wires subjected to pre-overpressure (pre-OP) treatment exhibit slightly improved resistance against indentation damage at shallow indentation depths. However, their critical current (I
c) deteriorates more rapidly at greater indentation depths when compared to wires that have not undergone the per-OP process. The following structural characterization analyzed the reasons for the property changes with the help of scanning electron microscopy, energy dispersive x-ray spectroscopy, computed tomography, and hardness tester. Misalignment between the Bi-2212 grains and shaped filaments was found in the indentation-damaged wires, with which the degradation in I
c of the wires and the differences in properties of the two kinds of wires were further discussed.
Collective excitations of a Bose–Einstein condensate of hard-core bosons and their mediated interactions: from two-body bound states to mediated superfluidity
Authors: Santiago-García Moroni , Camacho-Guardian Arturo
Published: September 2023

The exchange of collective modes has been demonstrated to be a powerful tool for inducing superconductivity and superfluidity in various condensed matter and atomic systems. In this article, we study the mediated interactions of collective excitations in an ultracold gas of hard-core bosons. We show that the induced interaction supports two-body states with energies, symmetries, and a number of bound states strongly dependent on the properties of the hard-core boson gas. The ability to control the nature of the two-body bound states motivates the study of superfluid phases, which we address within the BKT theory. We demonstrate how the superfluid parameters and critical temperatures can be tuned in our system. Our findings may pave the way for future theoretical and experimental studies with ultracold gases and solid-state systems.
Effect of p-MoOx interfacial layer on the photovoltaic performances of p-MoS2/n-Si heterojunction solar cells by theoretical simulation
Authors: Deng Quanrong , Lu Kun , Xiong Liwei , Shen Yonglong , Wang Geming , Wang Shenggao , Huang Wei
Published: September 2023

As one of particular 2D transition metal dichalcogenide materials, the outstanding properties of MoS2 enable the promising formation of superior homo or heterojunction solar cells. However, in the process of introducing oxygen treatment to modify the interface defects of MoS2/Si solar cells, or modulate the Fermi level of MoS2 films, a thin layer of p-MoOx capping layer is generally produced next to MoS2. In order to essentially clarify the functional mechanism of MoOx layer, p-MoS2/n-Si heterojunction solar cells with or without MoOx interfacial layer are simulated using SCAPS software. The influences of band gap, electron affinity, thickness of MoS2 and front contact barrier height on the performances of p-MoS2/n-Si solar cells are theoretically studied. It is demonstrated that p-MoS2/n-Si solar cell can achieve a high efficiency of 21.9%. With the appearance of MoOx, the effect of location, electron affinity and thickness of MoOx on the photovoltaic performances p-MoS2/n-Si heterojunction solar cells are studied. The efficiencies of p-MoS2/p-MoOx/n-Si solar cells are significantly reduced to be lower than 11.4%, p-MoOx/p-MoS2/n-Si solar cells maintain superior efficiencies over 20% in a large range of electron affinities lower than 3.0 eV for p-MoOx. Consequently, in modulating the Fermi level of MoS2 films through MoOx doping, p-MoOx capping layer is suggested to be located between MoS2 and front electrode rather than at p-MoS2/n-Si interface, to maintain the excellent performances of p-MoS2/n-Si solar cells.
Opportunities for cost-effective manufacturing of fully printed high performance displays enabled by vertical light-emitting transistor pixels
Authors: Vasilyeva Svetlana V , Chen Xiao , Katsui Hiromitsu , Miyachi Koichi , Huang Shao-Ting , Rinzler Andrew G , Lemaitre Maxime G , Liu Bo
Published: September 2023

With the vertical organic light-emitting transistor (VOLET), we introduce a promising solution that could significantly benefit the manufacturing of displays, accelerating the wide adoption of flexible and printed electronics. The VOLET—like conventional, lateral channel, organic thin film transistors—is compatible with a variety of printing techniques as well as flexible substrates and low-temperature processing. In combination these devices will enable a more cost-effective approach to mass-production that can dramatically extend the market potential of active-matrix organic light-emitting diode (AMOLED) displays. In this paper we discuss the prospects that AMOLED presents for the future of the display market, with a focus on the innovative VOLET device architecture. We assess how the integration of this device into active-matrix displays can contribute to the long range sustained competitiveness of AMOLED technology. We review recent progress in mass production techniques for printed electronics, with a particular emphasis on large-scale carbon nanotube material deposition. Finally, we explore the prospects for fully printed active-matrix light-emitting displays, including a review of high-performance printed components whose integration could facilitate the mass production of low-cost, high-performance, VOLET based AMOLEDs.
E-polynomials of character varieties for real curves
Authors: Baird Thomas , Wong Michael
Published: September 2023

We calculate the E-polynomial for a class of (complex) character varieties

M

n

τ

\mathcal {M}_n^{\tau }

associated to a genus

g
g

Riemann surface

Σ
\Sigma

equipped with an orientation reversing involution

τ
\tau

. Our formula expresses the generating function

∑

n
=
1

∞

E
(

M

n

τ

)

T
n

\sum _{n=1}^{\infty } E(\mathcal {M}_n^{\tau }) T^n

as the plethystic logarithm of a product of sums indexed by Young diagrams. The proof uses point counting over finite fields, emulating Hausel and Rodriguez-Villegas [Invent. Math. 174 (2008), pp. 555–624].
On global ACC for foliated threefolds
Authors: Liu Jihao , Luo Yujie , Meng Fanjun
Published: September 2023

In this paper, we prove the rational coefficient case of the global ACC for foliated threefolds. Specifically, we consider any lc foliated log Calabi-Yau triple

(
X
,

F

,
B
)

(X,\mathcal {F},B)

of dimension

3
3

whose coefficients belong to a set

Γ
\Gamma

of rational numbers satisfying the descending chain condition, and prove that the coefficients of

B
B

belong to a finite set depending only on

Γ
\Gamma

.

To prove our main result, we introduce the concept of generalized foliated quadruples, which is a mixture of foliated triples and Birkar-Zhang’s generalized pairs. With this concept, we establish a canonical bundle formula for foliations in any dimension.

As for applications, we extend Shokurov’s global index conjecture in the classical MMP to foliated triples and prove this conjecture for threefolds with nonzero boundaries and for surfaces. Additionally, we introduce the theory of rational polytopes for functional divisors on foliations and prove some miscellaneous results.
scAce: an adaptive embedding and clustering method for single-cell gene expression data
Authors: He Xinwei , Qian Kun , Wang Ziqian , Zeng Shirou , Li Hongwei , Li Wei Vivian
Published: September 2023

Motivation

Since the development of single-cell RNA sequencing (scRNA-seq) technologies, clustering analysis of single-cell gene expression data has been an essential tool for distinguishing cell types and identifying novel cell types. Even though many methods have been available for scRNA-seq clustering analysis, the majority of them are constrained by the requirement on predetermined cluster numbers or the dependence on selected initial cluster assignment.

Results

In this article, we propose an adaptive embedding and clustering method named scAce, which constructs a variational autoencoder to simultaneously learn cell embeddings and cluster assignments. In the scAce method, we develop an adaptive cluster merging approach which achieves improved clustering results without the need to estimate the number of clusters in advance. In addition, scAce provides an option to perform clustering enhancement, which can update and enhance cluster assignments based on previous clustering results from other methods. Based on computational analysis of both simulated and real datasets, we demonstrate that scAce outperforms state-of-the-art clustering methods for scRNA-seq data, and achieves better clustering accuracy and robustness.

Availability and implementation

The scAce package is implemented in python 3.8 and is freely available from https://github.com/sldyns/scAce.
Unintended Consequences: Risk of Opportunistic Infections Associated With Long-term Glucocorticoid Therapies in Adults
Authors: Chastain Daniel B , Spradlin Megan , Ahmad Hiba , Henao-Martínez Andrés F
Published: September 2023

Glucocorticoids are widespread anti-inflammatory medications used in medical practice. The immunosuppressive effects of systemic glucocorticoids and increased susceptibility to infections are widely appreciated. However, the dose-dependent model frequently used may not accurately predict the risk of infection in all patients treated with long-term glucocorticoids. In this review, we examine the risks of opportunistic infections (OIs) in patients requiring glucocorticoid therapy by evaluating the influence of the glucocorticoid dose, duration, and potency, combined with biological and host clinical factors and concomitant immunosuppressive therapy. We propose strategies to prevent OIs, which involve screening, antimicrobial prophylaxis, and immunizations. While this review focuses on patients with autoimmune, inflammatory, or neoplastic diseases, the potential risks and preventative strategies are likely applicable to other populations. Clinicians should actively assess the benefit–harm ratios of systemic glucocorticoids and implement preventive efforts to decrease their associated infections complications.
Tixagevimab and Cilgavimab (Evusheld) as Pre-exposure Prophylaxis for COVID-19 in Patients With Inflammatory Bowel Disease: A Propensity Matched Cohort Study
Authors: Desai Aakash , Hashash Jana G , Kochhar Gursimran S , Farraye Francis A
Published: September 2023

Background

Tixagevimab and cilgavimab (Evusheld) are 2 fully human monoclonal antibodies that received emergency-use authorization on December 21, 2021, for pre-exposure prophylaxis of coronavirus disease 2019 (COVID-19) in patients who are moderate–severely immunocompromised. The real-world efficacy of Evusheld in patients with inflammatory bowel disease (IBD) is not known.

Methods

We conducted a retrospective cohort study using TriNetX, a multi-institutional database in patients with IBD who received Evusheld compared to patients with IBD who did not receive Evusheld (12.1.2021–10.28.2022). The primary outcome was to assess the risk of COVID-19 within 6 months. One-to-one propensity score matching (PSM) was performed for demographic parameters, comorbid conditions, IBD medications, and history of COVID-19. Risk was expressed as adjusted odds ratio (aOR) with 95% confidence interval (CI).

Results

Four hundred and eight patients (0.19%) with IBD received Evusheld (mean age 58.6 ± 15.4 years old, female 47.7%) during the study period. After PSM, there was no difference in the risk (aOR 0.88, 95% CI, 0.33–2.35) of COVID-19 in the Evusheld cohort compared to the IBD control cohort. No patients required ICU care or intubation/respiratory support or were deceased in the Evusheld cohort.

Conclusions

Our study did not show that Evusheld decreases the risk of COVID-19 in patients with IBD. Prevention of moderate–severe COVID-19 in these patients should focus on vaccination strategies and early COVID-19 therapies.
The Mortality Effects of Winter Heating Prices
Authors: Chirakijja Janjala , Jayachandran Seema , Ong Pinchuan
Published: September 2023

This paper examines how the price of home heating affects mortality in the United States. Exposure to cold is one reason that mortality peaks in winter, and a higher heating price increases exposure to cold by reducing heating use. Our empirical approach combines spatial variation in the energy source used for home heating and temporal variation in the national prices of natural gas and electricity. We find that a lower heating price reduces winter mortality, driven mostly by cardiovascular and respiratory causes. Our estimates imply that the 42% drop in the natural gas price in the late 2000s, mostly driven by the shale gas boom, averted 12,500 deaths per year in the United States. The effect appears to be especially large in high-poverty communities.
The association between use of ambient voice technology documentation during primary care patient encounters, documentation burden, and provider burnout
Authors: Owens Lance M , Wilda Joshua J , Hahn Peter Y , Koehler Tracy , Fletcher Jeffrey J
Published: September 2023

Background

The burden of documentation in the electronic medical record has been cited as a major factor in provider burnout. The aim of this study was to evaluate the association between ambient voice technology, coupled with natural language processing and artificial intelligence (DAX™), on primary care provider documentation burden and burnout.

Methods

An observational study of 110 primary care providers within a community teaching health system. The primary objectives were to determine the association between DAX™ usage and provider burnout scores on the Oldenburg Burnout Inventory (OLBI) as well as the effect on documentation time per patient encounter (minutes).

Results

The completion rate for the survey was 75% (83/110) and high DAX™ use (>60% of encounters) was seen in 28% of providers (23/83). High DAX™ use was associated with significantly less burnout on the OLBI disengagement sub-score (MD [Mean Difference] −2.1; 95% confidence interval [CI] −3.8 to −0.4) but not the OLBI disengagement sub-score (−1.0; 95% CI −2.9 to 1.0) or total score (MD −3.0; 95% CI −6.4 to 0.3). Nineteen providers with high implementation of DAX™ had pre and postimplementation data on documentation time per encounter. After DAX™ implementation average documentation time in notes per encounter was significantly reduced by 28.8% (1.8 min; 95% CI 1.4–2.2).

Conclusions

The use of ambient voice technology during patient encounters was associated with significantly reduced documentation burden and primary care provider disengagement but not total provider burnout scores.
Multidisciplinary Inflammatory Bowel Disease Conference: The Impact of the Expert Pathologist on Patient Care
Authors: Kim Seo Hyun , Buhle Anna , Roberts Abra , Singh Neha , Mir Adil , Kesar Varun , Lozano Alicia , Ji Wenyan , Hanlon Alexandra , Grider Douglas
Published: September 2023

Background

Multidisciplinary teams (MDT) aid the diagnosis and management of patients with inflammatory bowel disease (IBD) and improve patient outcomes. The direct impact of a gastrointestinal expert pathologist on MDT care of IBD patients is unknown.

Methods

A retrospective chart review was conducted evaluating all cases (N = 289) discussed at the IBD MDT conference at Carilion Roanoke Memorial Hospital from June 1, 2013, through December 31, 2019. Cases were discussed between 1 and 6 times at the conference. Data collected included demographics, diagnosis before and after conference, reason for diagnostic change, endoscopy findings, medications, surgeries, and clinical follow-up.

Results

Approximately 15% to 42% of patients had a change in diagnosis after the first 3 conferences. The majority of diagnostic changes after the first (84%), second (73%), and third (67%) conferences were due to expert pathologist interpretation. Indeterminate colitis was the most frequently changed diagnosis, and Crohn’s disease was the most common new diagnosis after conference. Among patients with a diagnostic change, 28.6% to 38.5% of patients had a change in their IBD medication regimen, and 7.7% to 10.9% had a surgical intervention after the first 2 conferences. Approximately 54.2% to 60% of patients reported clinical improvement or remission within 6 months of the first 3 conferences.

Conclusion

The majority of diagnostic changes made at the multidisciplinary IBD conference were due to histopathologic re-interpretation. A change in diagnosis at times led to significant modifications in medical or surgical management. An expert gastrointestinal pathologist is an essential MDT member for IBD management.
Targeted Probiotics Against Bacterial-Fungal Biofilms: A New Concept Seems to Bring Us Closer to Microbiome-modulating Therapy for Inflammatory Bowel Disease
Authors: Sitkin Stanislav , Pokrotnieks Juris
Published: September 2023

Lay Summary

This article describes the concept of microbiome-modulating therapy for inflammatory bowel diseases using targeted probiotics. A designed probiotic composition is discussed as an example, the targets for which are polymicrobial bacterial-fungal biofilms specific for Crohn’s disease.