bluuebunny/crossref_metadata_2025 huggingface dataset:
Mother of dragons
Authors: Barnes A. T. , Liu J. , Zhang Q. , Tan J. C. , Bigiel F. , Caselli P. , Cosentino G. , Fontani F. , Henshaw J. D. , Jiménez-Serra I. , Kalb D.-S. , Law C. Y. , Longmore S. N. , Parker R. J. , Pineda J. E. , Sánchez-Monge A. , Lim W. , Wang K.
Published: April 2023

Context. Core accretion models of massive star formation require the existence of massive, starless cores within molecular clouds. Yet, only a small number of candidates for such truly massive, monolithic cores are currently known.

Aims. Here we analyse a massive core in the well-studied infrared-dark cloud (IRDC) called the ‘dragon cloud’ (also known as G028.37+00.07 or ‘Cloud C’). This core (C2c1) sits at the end of a chain of a roughly equally spaced actively star-forming cores near the center of the IRDC.

Methods. We present new high-angular-resolution 1 mm ALMA dust continuum and molecular line observations of the massive core.

Results. The high-angular-resolution observations show that this region fragments into two cores, C2c1a and C2c1b, which retain significant background-subtracted masses of 23 M⊙ and 2 M⊙ (31 M⊙ and 6 M⊙ without background subtraction), respectively. The cores do not appear to fragment further on the scales of our highest-angular-resolution images (0.2″, 0.005 pc ~ 1000 AU). We find that these cores are very dense (nH2 > 106 cm−3) and have only trans-sonic non-thermal motions (ℳs ~ 1). Together the mass, density, and internal motions imply a virial parameter of <1, which suggests the cores are gravitationally unstable, unless supported by strong magnetic fields with strengths of ~1–10 mG. From CO line observations, we find that there is tentative evidence for a weak molecular outflow towards the lower-mass core, and yet the more massive core remains devoid of any star formation indicators.

Conclusions. We present evidence for the existence of a massive, pre-stellar core, which has implications for theories of massive star formation. This source warrants follow-up higher-angular-resolution observations to further assess its monolithic and pre-stellar nature.
Soft gamma-ray spectral and time evolution of the GRB 221009A: Prompt and afterglow emission with INTEGRAL/IBIS-PICsIT
Authors: Rodi James , Ubertini Pietro
Published: April 2023

Aims. The gamma-ray burst (GRB) 221009A, with its extreme brightness, has provided the opportunity to explore GRB prompt and afterglow emission behavior on short timescales with high statistics. In conjunction with detection up to very-high-energy gamma rays, studies of this event shed light on the emission processes at work in the initial phases of GRBs’ emission.

Methods. Using INTEGRAL/IBIS’s soft gamma-ray detector, PICsIT (200–2600 keV), we studied the temporal and spectral evolution during the prompt phase and the early afterglow period.

Results. We found a “flux-tracking” behavior with the source spectrum “softer” when brighter. However, the relationship between the spectral index and the flux changes during the burst. The PICsIT light curve shows that afterglow emission begins to dominate at ∼T0 + 630 s and decays with a slope of 1.6 ± 0.2, consistent with the slopes reported at soft X-rays.
Toward a pulsed antihydrogen beam for WEP tests in AEgIS
Authors: Huck Saiva , Auzins Marcis , Bergmann Benedikt , Burian Petr , Brusa Roberto S. , Camper Antoine , Caravita Ruggero , Castelli Fabrizio , Ciuryło Roman , Consolati Giovanni , Doser Michael , Farricker Aaron , Glöggler Lisa T. , Graczykowski Łukasz , Grosbart Malgorzata , Guatieri Francesco , Gusakova Natali , Haider Stefan , Janik Malgorzata , Kasprowicz Grzegorz , Khatri Ghanshyambhai , Kłosowski Łukasz , Kornakov Georgy , Krumins Valts , Lappo Lidia , Linek Adam , Malbrunot Chloé , Mariazzi Sebastiano , Nowak Lilian , Nowicka Dorota , Oswald Emmanuel , Penasa Luca , Petracek Vojtech , Piwiński Mariusz , Pospisil Stanislav , Povolo Luca , Prelz Francesco , Rangwala Sadiq , Rienäcker Benjamin , Rodin Volodymyr , Røhne Ole M. , Sandaker Heidi , Smolyanskiy Petr , Sowiński Tomasz , Tefelski Dariusz , Volponi Marco , Welsch Carsten , Wolz Tim , Zawada Michal , Zielinski Jakub , Zimmer Christian , Zurlo Nicola
Published: April 2023

The AEg̅IS collaboration at CERN’s AD produces antihydrogen atoms in the form of a pulsed, isotropic source with a precisely defined formation time. AEg̅IS has recently undergone major upgrades to fully benefit from the increased number of colder antiprotons provided by the new ELENA decelerator and to move toward forming a horizontal beam to directly investigate the influence of gravity on the H̅ atoms, thereby probing the Weak Equivalence Principle for antimatter. This contribution gives an overview of these upgrades as well as subsequent results from the first beam times with ELENA.
The search of Axion Dark Matter with a dielectric halo-scope: MADMAX
Authors: Majorovits Béla
Published: April 2023

The strong CP problem is one of the most fundamental unresolved questions in the standard model of particle physics. The axion, emerging due to the maybe most elegant solution to the strong CP problem, could also solve the long standing dark matter problem. A short introduction to the strong CP problem is given. The axion as a dark matter candidate is discussed. The detection technology via inverse Primakoff effect using a dielectric haloscope is described. The MADMAX project is introduced and the status on the road towards its realization is given.
Systematic effects in the search for the muon electric dipole moment using the frozen-spin technique
Authors: Dutsov Chavdar , Hume Timothy , Schmidt-Wellenburg Philipp
Published: April 2023

At the Paul Scherrer Institute (PSI) we are developing a high precision instrument to measure the muon electric dipole moment (EDM). The experiment is based on the frozen-spin method in which the spin precession induced by the anomalous magnetic moment is suppressed, thus increasing the signal-to-noise ratio for EDM signals to achieve a sensitivity otherwise unattainable using conventional g - 2 muon storage rings. The expected statistical sensitivity for the EDM after a year of data taking is 6 10−23e cm with the p = 125 MeV/c muon beam available at the PSI. Reaching this goal necessitates a comprehensive analysis on spurious effects that mimic the EDM signal. This work discusses a quantitative approach to study systematic effects for the frozen-spin method when searching for the muon EDM. Equations for the motion of the muon spin in the electromagnetic fields of the experimental system are analytically derived and validated by simulation.
Study of an entropy dissipating finite volume scheme for a nonlocal cross-diffusion system
Authors: Herda Maxime , Zurek Antoine
Published: April 2023

In this paper we analyse a finite volume scheme for a nonlocal version of the Shigesada–Kawazaki–Teramoto (SKT) cross-diffusion system. We prove the existence of solutions to the scheme, derive qualitative properties of the solutions and prove its convergence. The proofs rely on a discrete entropy-dissipation inequality, discrete compactness arguments, and on the novel adaptation of the so-called duality method at the discrete level. Finally, thanks to numerical experiments, we investigate the influence of the nonlocality in the system: on convergence properties of the scheme, as an approximation of the local system and on the development of diffusive instabilities.
An application of a smart production system to control deteriorated inventory
Authors: Bhuniya Shaktipada , Guchhait Rekha , Ganguly Baishakhi , Pareek Sarla , Sarkar Biswajit , Sarkar Mitali
Published: April 2023

Deteriorating products require different handling procedures. Handling procedures includes prevention of the natural deterioration rate of the product. The production of deteriorating products requires prevention technology for those products to use for a long time. Overproduction of deteriorating types of products causes more trouble in preventing deterioration. This study uses a smart production system to control the production of deteriorating products. A controllable production rate controls the production of deteriorating products, and preservation technology reduces the deterioration rate of products. Preservation technology helps extend the life of products, but it requires a specific temperature controlled environment to work at maximum efficiency. Transportation of these products uses refrigerated transportation to maintain the quality during the transportation time. The purpose of using all these features for deteriorating products is to reduce the deterioration rate, which helps to reduce waste generation from production. Besides, imperfect products from the production system pass through a remanufacturing process to support the waste reduction process. A sustainable supply chain management model under the above-stated strategies is described here. Classical optimization is used to find the global optimum solution of the objective function. Then, the total cost of the supply chain is optimized using unique solutions of production rate, number of deliveries, delivery lot size, system reliability, and preservation investment. Global optimum solutions are established theoretically, and few propositions are developed. Some special cases, case studies, and a comparison graph are provided to validate the results. The beta distribution provides the minimum total cost of the system than uniform, gamma, triangular, and double triangular distribution. Smart production allows 72% system reliability with negligible imperfect products. Besides, the proposed policy gains 22.72% more profit than the existing literature. The model is more realistic through convex 3D graphs, sensitivity analyses, and managerial insights.
Manganese-Catalyzed ortho-Hydroalkylation of Aryl-Substituted N-Heteroaromatic Compounds with Maleimides
Authors: Shinde Vikki N. , Bhawani Bhawani , Kumar Anil , Nipate Dhanajay S. , Sonam Sonam , Meena Neha , Rangan Krishnan , Kumar Dalip
Published: April 2023

A regioselective manganese-catalyzed ortho-hydroalkylation of aryl-substituted N-heteroaromatic compounds with a range of maleimides is described. The developed C–H bond functionalization protocol allowed the introduction of the succinimide motif at the ortho-position of the aryl ring of N-heteroaromatic compounds, such as 2-arylimidazo[1,2-a]pyridines, 2-arylindazoles, 2-phenylpyridine, 2-phenyl­pyrimidine, 2-phenylimidazo[1,2-a]pyrimidine, 2-phenylimidazo[2,1-b]thiazole, 2-phenylbenzo[d]imidazo[2,1-b]thiazole, 1-phenylindazole and 1-phenylpyrazole, to produce 3-(2-(N-heteroaryl)aryl)pyrrolidine-2,5-diones in good yields. The protocol exhibited broad substrate scope, good functional group tolerance and excellent regioselectivity under mild and additive-free reaction conditions.
Palladium-Catalyzed Asymmetric 1,4-Addition of Diarylphosphines to α,β-Unsaturated Sulfonyl Fluorides
Authors: Duan Wei-Liang , Cheng An-Qi , Wu Zeng-Hua , Yang Huai-Lan
Published: April 2023

A Pd-catalyzed asymmetric phosphination of α,β-unsaturated sulfonyl fluorides was developed, and a series of tertiary phosphorus compounds were obtained in excellent yields and enantioselectivities (up to 99% ee). The chiral adduct can be further converted into chiral phosphine sulfonic acid as the ligand for the arene Ru metal complex.
Long-term outcomes of Zenker’s peroral endoscopic myotomy (Z-POEM) for treatment of Zenker’s diverticulum
Authors: Steinway Steven , Zhang Linda , Amundson Julia , Nieto Jose , Desai Pankaj , Jacques Jeremie , Bejjani Michael , Pioche Mathieu , Kumta Nikhil , Hernandez-Mondragon Oscar , Ujiki Michael , Khashab Mouen
Published: April 2023

Background and study aims Z-POEM is now an established therapy for symptomatic Zenker’s diverticulum (ZD). Short-term follow-up of up to 1-year post Z-POEM suggests excellent efficacy and safety; however, long-term outcomes are not known. Thus, we sought to report on longer-term outcomes (≥ 2 years) following Z-POEM for treatment of ZD.

Patients and methods This was an International multicenter retrospective study at eight institutions across North America, Europe, and Asia over a 5-year period (from December 3, 2015 to March 13, 2020) of patients who underwent Z-POEM for management of ZD with a minimum 2-year follow-up. The primary outcome was clinical success, defined as improvement in dysphagia score to ≤ 1 without need for further procedures during the first 6 months. Secondary outcomes included rate of recurrence in patients initially meeting clinical success, rate of reintervention, and adverse events (AEs).

Results A total of 89 patients (male 57.3 %, mean age 71 ± 12 years) underwent Z-POEM for treatment of ZD (mean diverticulum size was 3.4 ± 1.3 cm). Technical success was achieved in 97.8 % of patients (n = 87) with a mean procedure time of 43.8 ± 19.2 minutes. The median post-procedure hospital stay was 1 day. There were eight AEs (9 %) (3 mild, 5 moderate). Overall, clinical success was achieved in 84 patients (94 %). Mean dysphagia, regurgitation, and respiratory scores all improved dramatically from 2.1 ± 0.8, 2.8 ± 1.3, and 1.8 ± 1.6 pre-procedure to 0.13 ± 0.5, 0.11 ± 0.5, and 0.05 ± 0.4, respectively, post-procedure at most recent follow-up (all P < 0.0001). Recurrence occurred in six patients (6.7 %) during a mean length of follow-up of 37 months (range 24 to 63 months).

Conclusions Z-POEM is a highly safe and effective treatment for Zenker’s diverticulum with durable treatment effect to at least 2 years.
Imaging of Anatomical Variants of the Long Head Biceps Tendon
Authors: Fischetti Michele , Romano Alfonso Maria , Albano Domenico , Di Salvatore Mariano Giuseppe , Sconfienza Luca Maria , Zappia Marcello
Published: April 2023

Anatomical variants of the long head of biceps (LHB) tendon are widely discussed in the literature. As one of the few intra-articular tendons, magnetic resonance arthroscopy can quickly evaluate the proximal part of LHB morphology. It provides good assessment of both intra-articular and extra-articular portions of the tendons. In-depth knowledge about imaging of the anatomical LHB variants discussed in this article is useful preoperatively for orthopaedists and also helps avoid potential diagnostic misinterpretations.
Anatomical Variants of the Upper Limb Nerves: Clinical and Preoperative Relevance
Authors: Schwabl Christoph , Hörmann Romed , Strolz Carola Johanna , Drakonaki Elena , Zimmermann Robert , Klauser Andrea Sabine
Published: April 2023

Profound knowledge of nerve variations is essential for clinical practice. It is crucial for interpreting the large variability of a patient's clinical presentation and the different mechanisms of nerve injury. Awareness of nerve variations facilitates surgical safety and efficacy. Clinically significant anatomical variations can be classified into two main groups: variability in the course of the nerve and variability of structures surrounding the nerve. In this review article we focus on the most common nerve variants of the upper extremity and their clinical relevance.
Anatomical Variants of the Sacroiliac Joint
Authors: Badr Sammy , Khizindar Huda , Boulil Youssef , Abou Diwan Ralph , Demondion Xavier , Cotten Anne
Published: April 2023

Anatomical variants are frequently encountered when assessing the sacroiliac joints (SIJ) using magnetic resonance imaging. When not located in the weight-bearing part of the SIJ, variants associated with structural and edematous changes can be misinterpreted as sacroiliitis. Their correct identification is necessary to avoid radiologic pitfalls. This article reviews five SIJ variants involved in the dorsal ligamentous space (accessory SIJ, iliosacral complex, semicircular defect, bipartite iliac bony plate, and crescent iliac bony plate) and three SIJ variants involved in the cartilaginous part of the SIJ (posterior dysmorphic SIJ, isolated synostosis, and unfused ossification centers).
Ulam–Hyers stability for second-order non-instantaneous impulsive fractional neutral stochastic differential equations
Authors: K. Dhanalakshmi , P. Balasubramaniam
Published: April 2023

In this paper, sufficient conditions are established for the Ulam–Hyers stability of second-order non-instantaneous impulsive fractional neutral stochastic differential equations (NIIFNSDEs) with supremum norm in the pth means square sense. The existence of solution of NIIFNSDEs is derived by using the cosine family of linear operator, Itô’s formula, and Mönch fixed point theorem in infinite-dimensional space. Finally, an example is demonstrated to illustrate the obtained theoretical results.
On the Hochstadt–Lieberman theorem for the fourth-order binomial operator
Authors: Chen Lu , Shi Guoliang , Yan Jun
Published: April 2023

A method of recovering the potential of the fourth-order binomial operator on a half-interval [1/2, 1] using a known potential on another half-interval [0, 1/2] and the eigenvalues of the self-adjoint boundary problem on the whole interval [0, 1] is proposed.
Wong–Zakai approximations for non-autonomous stochastic parabolic
equations with X-elliptic operators in higher regular
spaces
Authors: Gao Lili , Huang Ming , Yang Lu
Published: April 2023

In this paper, we consider the regularity of Wong–Zakai approximations of the non-autonomous stochastic degenerate parabolic equations with X-elliptic operators. We first establish the pullback random attractors for the random degenerate parabolic equations with a general diffusion. Then, we prove the convergence of solutions and the upper semi-continuity of random attractors of the Wong–Zakai approximation equations in Lp(DN) ∩ H.
Performance of small- and wide-angle x-ray scattering beamline at Indus-2 synchrotron
Authors: Das Avik , Bahadur Jitendra , Kumar Ashwani , Sen Debasis
Published: April 2023

A Small- and Wide-Angle X-ray Scattering (SWAXS) beamline (BL-18) is installed and commissioned at a 1.5 T bending magnet port (5°) of Indus-2 synchrotron at RRCAT, Indore, India. The ∼40-m-long beamline has tunable x-ray energy in the range of 5–20 keV by using a double crystal monochromator. A 1.5-m-long toroidal mirror is used to focus the x-ray beam at the detector position. The beamline is equipped with a 6-m-long movable detector stage to access different wave-vector transfer ranges. At present, an online image plate area detector and a linear position-sensitive gas detector are installed for Small-Angle X-ray Scattering (SAXS) and Wide-Angle X-ray Scattering (WAXS) measurements, respectively. The beamline is operational in simultaneous SAXS/WAXS mode to probe the mesoscopic as well as molecular level structure over a wide range of wave-vector transfer. The specification of the beamline and its performance are reported here. A few recent experimental results, as obtained from BL-18, are also described in brief.
Broadband microwave absorption effects in 2D nitrogen capacitively coupled plasma under different operating conditions
Authors: Ouyang Wenchong , Liu Qi , Ding Chengbiao , Wu Zhengwei
Published: April 2023

In recent years, the interaction of electromagnetic waves (EM) with plasma sources under argon and helium discharges has been extensively studied due to its potential applications in plasma stealth. However, nitrogen, as a more economical discharge gas, has been ignored in terms of its absorption of EM waves and stealth effect. In this work, a numerical calculation model combining two-dimensional capacitively coupled plasma (CCP) fluid model and EM wave model was developed to investigate the plasma uniformity degree and broadband microwave absorption effects in helium and nitrogen CCP. It is concluded that the two-dimensional model in this paper has more accurate and reasonable through comparison with the one-dimensional and experimental results in helium CCP. Nitrogen CCP shows better broadband absorption effects than that of helium, and helium plasma has better uniformity than nitrogen under the same discharge parameters. But the uniformity degree of nitrogen plasma is not much different from that of helium under the same electron density, which means that nitrogen can significantly improve its broadband wave absorption properties to some extent without loss of uniformity degree. Based on the above conclusions, the absorption characteristics of nitrogen CCP under different radio frequency (RF) power and pressure are analyzed. The attenuation effect of nitrogen CCP increases with the increasing RF power, and it is interesting that the influence of pressure on the attenuation of EM waves is not monotonically increasing, and the related mechanism is discussed. Finally, discussion of skin depth under different RF power and pressure validates the above conclusions. The absorption band of nitrogen CCP under the best parameters in this work can reach the X-band, which shows great application potential in plasma stealth.
Solving the non-local Fokker–Planck equations by deep learning
Authors: Jiang Senbao , Li Xiaofan
Published: April 2023

Physics-informed neural networks (PiNNs) recently emerged as a powerful solver for a large class of partial differential equations (PDEs) under various initial and boundary conditions. In this paper, we propose trapz-PiNNs, physics-informed neural networks incorporated with a modified trapezoidal rule recently developed for accurately evaluating fractional Laplacian and solve the space-fractional Fokker–Planck equations in 2D and 3D. We describe the modified trapezoidal rule in detail and verify the second-order accuracy. We demonstrate that trapz-PiNNs have high expressive power through predicting the solution with low L 2 relative error by a variety of numerical examples. We also use local metrics, such as point-wise absolute and relative errors, to analyze where it could be further improved. We present an effective method for improving the performance of trapz-PiNN on local metrics, provided that physical observations or high-fidelity simulation of the true solution are available. The trapz-PiNN is able to solve PDEs with fractional Laplacian with arbitrary α ∈ ( 0 , 2 ) and on rectangular domains. It also has the potential to be generalized into higher dimensions or other bounded domains.
The nonlocal electron heat transport under the non-Maxwellian distribution in laser plasmas and its influence on laser ablation
Authors: Li Kai , Huo Wen Yi
Published: April 2023

The electron heat transport plays an important role in laser driven inertial confinement fusion. For the plasmas created by intense laser, the traditional Spitzer–Härm theory cannot accurately describe the electron heat transport process mainly due to two physical effects. First, the electron distribution function would significantly differ from the Maxwellian distribution because of the inverse bremsstrahlung heating. Second, the long mean free paths of heat carrying electrons relative to the temperature scale length indicate that the electron heat flux has the nonlocal feature. In 2020, we have developed a nonlocal electron heat transport model based on the non-Maxwellian electron distribution function (NM-NL model) to describe the electron heat flux in laser plasmas. Recently, this model is successfully incorporated into our radiation hydrodynamical code RDMG. In this article, we numerically investigated the electron heat flux in laser plasmas, especially the nonlocal feature of heat flux and the influence of the non-Maxwellian distribution. The influence of electron heat transport on laser ablation is also discussed. The simulated plasma conditions based on different electron heat transport models are presented and compared with experiments. Our results show that the nonlocal feature of heat flux and the influence of non-Maxwellian distribution function are considerable in plasmas heated by intense lasers.
Some perturbation results for quasi-bases and other sequences of vectors
Authors: Bagarello Fabio , Corso Rosario
Published: April 2023

We discuss some perturbation results concerning certain pairs of sequences of vectors in a Hilbert space H and producing new sequences, which share, with the original ones, reconstruction formulas on a dense subspace of H or on the whole space. We also propose some preliminary results on the same issue, but in a distributional settings.
Focused laser differential interferometry post-processing methodology for flowfields with circular symmetry
Authors: Camillo Giannino Ponchio , Wagner Alexander
Published: April 2023

An analytic methodology is presented to reconstruct the pressure waveform of flowfields with circular symmetry from the phase shift detected with Focused Laser Differential Interferometry (FLDI). A weak blast wave generated by an electric spark in ambient air is investigated with the proposed approach. Values of separation distance between the differentiating foci of the FLDI Δx of 76, 120, 175, and 252 μm are employed to probe the flowfield at locations between 3 and 50 mm from the spark source. In a subset of these distances, reference measurements of peak pressure obtained with a surface pressure sensor indicate good agreement with the reconstructed data when small separation distances are used. Further analysis of FLDI reconstructed data is conducted using theoretical correlations for N-waves in terms of the distribution of pressure peak amplitude and compression phase as the wave front propagates. Agreement with theory is verified for all differentiation separation distances except the largest, for which peak pressure comparison shows a 10% loss of measured vs predicted value. A computational FLDI is employed to scrutinize the simplifying hypotheses supporting the waveform reconstruction approach. The direct comparison between experimental and computational FLDI output reveals additional discrepancies for intermediate Δx values but very good agreement for the smallest Δx. The proposed methodology is thus verified to be reasonable, upon appropriate minimization of the FLDI differentiation distance. A parametric analysis using computational FLDI indicates the adequate value of FLDI Δx to be 20% or less of the flowfield characteristic length in terms of density gradient.
Simulations of energy deposition of electron cyclotron waves in a dipole-confined plasma based on ray trajectory
Authors: Ma Hao-Jie , Xie Hua-Sheng , Li Bo
Published: April 2023

The energy deposition of electron cyclotron waves in a dipole-confined plasma is investigated for the RT-1 device, specifically including the effects of high-energy electrons and the electron Bernstein wave (EBW) excitation and absorption. Simulations of wave trajectories with various injection locations and angles indicate that the energy deposition of ordinary mode (O-mode) and extraordinary modes (X-mode) is small in low-temperature plasmas. The high-energy electrons in the plasma increase the energy deposition of the X-mode but have little effect on the O-mode. Meanwhile, the energy deposition of the slow X-EBW conversion and O-X-EBW conversion to excite EBW is also discussed. The results show that the converted EBW in an over-dense plasma is easily obtained, but it may not always have efficient energy deposition. Finally, the possible mechanism for the plasma production and heating by using electron cyclotron waves is proposed.
Fully stretchable and skin-mountable ionic-gated organic phototransistors based on elastomeric semiconductor and dielectric
Authors: Yang Jiaxin , Jin Chunyang , Hu Binlai , Liu Guokeng , Xu Haihua
Published: April 2023

Soft optoelectronics that can be naturally conformable to human skins for noninvasive light-tissue interplays are inspiring for the realization of human–machine interactions, health monitoring, and soft robotics. Advances in material and structural engineering have been made to realize various skin-like electronics/optoelectronics. However, there still exist great challenges such as procedure complexity and high-power dissipation that seriously impede practical applications for these devices. In this work, we demonstrate a fully stretchable and skin-mountable ionic-gated organic phototransistor with an ultra-low power dissipation of 3 nW, high sensitivity up to 103, and a mechanical stretchability of ε = 20%. The phototransistor is composed of an elastomeric ionic gate dielectric layer with ultrahigh capacitance over 1 μF/cm2 and high stretchability up to ε = 50%. Strain-insensitive photodetection of the device is achieved by the nanoconfinement effect existing inside the intrinsically stretchable photoactive semiconductor layer via blending elastic and insulative polymers into an organic bulk heterojunction. Combining with its pronounced electromechanical properties, the stretchable photodetector can be conformable to various body parts for real-time and noninvasive monitoring on different pulse-waves, demonstrating the ability of low-cost and in-home supervision on chronic diseases in daily life.
Detecting hidden nodes in networks based on random variable resetting method
Authors: Jiang Weinuo , Wang Shihong
Published: April 2023

Reconstructing network connections from measurable data facilitates our understanding of the mechanism of interactions between nodes. However, the unmeasurable nodes in real networks, also known as hidden nodes, introduce new challenges for reconstruction. There have been some hidden node detection methods, but most of them are limited by system models, network structures, and other conditions. In this paper, we propose a general theoretical method for detecting hidden nodes based on the random variable resetting method. We construct a new time series containing hidden node information based on the reconstruction results of random variable resetting, theoretically analyze the autocovariance of the time series, and finally provide a quantitative criterion for detecting hidden nodes. We numerically simulate our method in discrete and continuous systems and analyze the influence of main factors. The simulation results validate our theoretical derivation and illustrate the robustness of the detection method under different conditions.
Effects of pulse rise time on electron dynamics properties in nitrogen–oxygen mixture under repetitive nanosecond pulses
Authors: Li Chenjie , Zheng Xinlei , Wang Yifeng , Liu Shuhan , Zhao Zheng , Li Jiangtao
Published: April 2023

The effects of pulse rise time on the temporal evolution of electron energy and density under repetitive nanosecond pulses in atmospheric nitrogen with 100 ppm oxygen impurities are investigated in this paper by a two-dimensional particle-in-cell/Monte Carlo collision model. It is found that the peak value of mean electron energy increases with decreasing pulse rise time in the single pulsed discharge. However, in the repetitive pulsed discharge approximated by pre-ionization, the peak value of mean electron energy no longer varies with the pulse rise time, showing a saturation trend with decreasing pulse rise time. Whether or not pre-ionization is present, the time required for the mean electron energy to reach its peak is approximately equal to the pulse rise time. It is worth noting that the presence of pre-ionization enhances the tracking ability of the mean electron energy to the pulse waveform during the pulse rise edge. Although after the peak of the pulse, the mean electron energy terminates the tracking process to pulse waveform due to the formation of high-density avalanches and even streamers, its energy decay rate gradually decreases with the increase in the pre-ionization density. Therefore, when the pulse repetitive frequency is greatly increased or the pre-ionization density is increased by other means, it is possible to achieve the complete control of the mean electron energy by pulse waveform modulation.
Maximum entropy states of collisionless positron–electron plasma in a dipole magnetic field
Authors: Sato Naoki
Published: April 2023

We are developing a positron–electron plasma trap based on a dipole magnetic field generated by a levitated superconducting magnet to investigate the physics of magnetized plasmas with mass symmetry as well as antimatter components. Such laboratory magnetosphere is deemed essential for the understanding of pair plasmas in astrophysical environments, such as magnetars and blackholes, and represents a novel technology with potential applications in antimatter confinement and the development of coherent gamma-ray lasers. The design of the device requires a preemptive analysis of the achievable self-organized steady states. In this study, we construct a theoretical model describing maximum entropy states of a collisionless positron–electron plasma confined by a dipole magnetic field and demonstrate efficient confinement of both species under a wide range of physical parameters by analyzing the effect of the three adiabatic invariants on the phase space distribution function. The theory is verified by numerical evaluation of spatial density, electrostatic potential, and toroidal rotation velocity for each species in correspondence with the maximum entropy state.
Suppression of effects of temperature variation by high-order frequency modulation in large fiber-optic gyroscopes
Authors: Chen Yanjun , Cao Yuwen , Zhu Lanxin , He Yan , Wang Wenbo , Huang Huimin , Ma Xiangdong , Li Zhengbin
Published: April 2023

Temperature variation degrades the performance of fiber-optic gyroscopes. In terms of a noise mechanism, we report that thermal phase noise contributes to the dominant effect of temperature variation in large fiber-optic gyroscopes when the conventional Shupe effect is basically suppressed. High-order frequency modulation is introduced to reduce the corresponding effect of temperature variation. A time-varying temperature variation experiment has been carried out for verification. Compared with the conventional eigen frequency modulation, the temperature sensitivity is reduced by 32 times, which effectively enhances the temperature adaptability of the fiber-optic gyroscope.
A new high-pressure high-temperature deformation apparatus to study the brittle to ductile transition in rocks
Authors: Meyer G. G. , Acosta M. , Leclere H. , Morier L. , Teuscher M. , Garrison G. , Schubnel A. , Violay M.
Published: April 2023

Understanding the micro-mechanisms underlying the localized–ductile transition (LDT) as well as the brittle–plastic transition (BPT) has become crucial for our wider understanding of crustal processes and seismicity. Given how difficult in situ observations of these transitions are to perform, laboratory experiments might be our only way to investigate the processes active under these conditions (high T and high P). Here, we present Triaxial AppaRatus for GEoThermal energy, a new gas-based triaxial apparatus located at EPFL in Switzerland that was specifically designed to operate under conditions where both the LDT and BPT can occur in geomaterials. We show that the machine is capable of deforming rock samples at confining pressures of up to 400 MPa, temperatures of up to 800 °C, and pore pressures (liquid or gas) of up to 300 MPa while keeping the temperature gradient along samples of 40 mm in length and 20 mm in diameter minimal (less than 30 at 700 °C). Most importantly, the maximum load is 1000 kN (stresses as high as 2.2 GPa on 24 mm samples and 3 GPa on 20 mm samples), allowing for the deformation of very competent rock samples. Moreover, during deformation, the pair of syringe pore pressure pumps allow for continuous permeability or dilatancy recording. We benchmarked our machine against existing data in the literature and show that it accurately and precisely records stress, strain, permeability, pressure, and temperature.
High efficiency radio frequency antennas for amplifier free quantum sensing applications
Authors: Mahtab S. , Milas P. , Veal D.-T. , Spencer M. G. , Ozturk B.
Published: April 2023

Radio frequency (RF) signals are frequently used in emerging quantum applications due to their spin state manipulation capability. Efficient coupling of RF signals into a particular quantum system requires the utilization of carefully designed and fabricated antennas. Nitrogen vacancy (NV) defects in diamond are commonly utilized platforms in quantum sensing experiments with the optically detected magnetic resonance (ODMR) method, where an RF antenna is an essential element. We report on the design and fabrication of high efficiency coplanar RF antennas for quantum sensing applications. Single and double ring coplanar RF antennas were designed with −37 dB experimental return loss at 2.87 GHz, the zero-field splitting frequency of the negatively charged NV defect in diamond. The efficiency of both antennas was demonstrated in magnetic field sensing experiments with NV color centers in diamond. An RF amplifier was not needed, and the 0 dB output of a standard RF signal generator was adequate to run the ODMR experiments due to the high efficiency of the RF antennas.
Koopman analysis of the periodic Korteweg–de Vries equation
Authors: Parker Jeremy P. , Valva Claire
Published: April 2023

The eigenspectrum of the Koopman operator enables the decomposition of nonlinear dynamics into a sum of nonlinear functions of the state space with purely exponential and sinusoidal time dependence. For a limited number of dynamical systems, it is possible to find these Koopman eigenfunctions exactly and analytically. Here, this is done for the Korteweg–de Vries equation on a periodic interval using the periodic inverse scattering transform and some concepts of algebraic geometry. To the authors’ knowledge, this is the first complete Koopman analysis of a partial differential equation, which does not have a trivial global attractor. The results are shown to match the frequencies computed by the data-driven method of dynamic mode decomposition (DMD). We demonstrate that in general, DMD gives a large number of eigenvalues near the imaginary axis and show how these should be interpreted in this setting.
Densest packing of flexible polymers in 2D films
Authors: Pedrosa Clara , Martínez-Fernández Daniel , Herranz Miguel , Foteinopoulou Katerina , Karayiannis Nikos Ch. , Laso Manuel
Published: April 2023

How dense objects, particles, atoms, and molecules can be packed is intimately related to the properties of the corresponding hosts and macrosystems. We present results from extensive Monte Carlo simulations on maximally compressed packings of linear, freely jointed chains of tangent hard spheres of uniform size in films whose thickness is equal to the monomer diameter. We demonstrate that fully flexible chains of hard spheres can be packed as efficiently as monomeric analogs, within a statistical tolerance of less than 1%. The resulting ordered polymer morphology corresponds to an almost perfect hexagonal triangular (TRI) crystal of the p6m wallpaper group, whose sites are occupied by the chain monomers. The Flory scaling exponent, which corresponds to the maximally dense polymer packing in 2D, has a value of ν = 0.62, which lies between the limits of 0.50 (compact and collapsed state) and 0.75 (self-avoiding random walk).
Relation of stability and bifurcation properties between continuous and ultradiscrete dynamical systems via discretization with positivity: One dimensional cases
Authors: Ohmori Shousuke , Yamazaki Yoshihiro
Published: April 2023

The stability and bifurcation properties of one-dimensional discrete dynamical systems with positivity, which are derived from continuous ones by tropical discretization, are studied. The discretized time interval is introduced as a bifurcation parameter in the discrete dynamical systems, and the emergence condition of an additional bifurcation, flip bifurcation, is identified. The correspondence between the discrete dynamical systems with positivity and the ultradiscrete ones derived from them is discussed. It is found that the derived ultradiscrete max-plus dynamical systems can retain the bifurcations of the original continuous ones via tropical discretization and ultradiscretization.
The effects of pulse voltage rise time on the nanosecond pulsed breakdown of nitrogen spark switch at atmospheric pressure with 3D PIC-MCC model
Authors: Wang Yongliang , Li Junna , Jiang Ming , Li Qisheng , Li Chunan , Li Shiji , Wang Haoyan , Qiu Aici
Published: April 2023

In this paper, the effects of pulse voltage rise time on the nanosecond pulsed breakdown of the nitrogen spark switch at atmospheric pressure are analyzed. Based on the assumption of initial electrons generation due to the field emission, the simulations are performed using a three-dimensional particle-in-cell, Monte Carlo-collision model for the pulse voltage with a rise time of 40, 60, and 100 ns, respectively. The breakdown experiments of the nitrogen spark switch are carried out for three different rise times. The results obtained are as follows. First, the nanosecond pulsed breakdown of the switch includes the formation and fast propagation of the streamer, which depend on the multiplication of the electron avalanche, and the intense ionization due to photoelectrons and energetic electrons, respectively. Second, with the rise time of pulse voltage increasing, the generation of runaway electrons becomes more difficult and the streamer branches, which are mainly caused by photoionization and captured energetic electrons, become more obvious. Finally, the breakdown time delay of the switch becomes shorter and the breakdown voltage becomes higher at the same pressure for the decreasing rise time of pulse voltage, which is consistent with the measurement results.
Spatiotemporal theory of the sectioned gyro-BWO with the zigzag quasi-optical system
Authors: Novak E. M. , Samsonov S. V. , Savilov A. V.
Published: April 2023

We present the quasi-analytical spatiotemporal theory, which describes the process of establishing generation in a backward-wave gyro-oscillator based on the use of a sectioned quasi-optical system with the zigzag path of the operating wave beam. This theory explains peculiarities (namely, a piecewise character) of changing the operating frequency and power of the output signal in the process of the broadband frequency tuning provided by changing the operating magnetic field. This theory also describes competition of different modes of the system in the process of excitation of auto-oscillators and predicts the possibility for realization of the regime of automodulations of the output power, as well as the regime of formation of a short powerful super-radiant pulse.
Evolution of unsteady vortex structures in the tip region of an axial compressor rotor
Authors: Hou Jiexuan , Liu Yangwei
Published: April 2023

The evolution of unsteady vortex structures in the tip region of an axial compressor rotor is investigated based on delayed detached eddy simulation. The vortex structures are identified by the LTcri method, and the velocity fields are visualized by the particle tracing method. The results show that the evolution of the tip leakage vortex (TLV) can be divided into three phases: the generation phase, the development phase, and the dissipation phase. The unsteadiness of the flow field mainly appears in the dissipation phase as a consequence of the unsteady secondary tip leakage. There are three primary unsteady vortex structures caused by the tip leakage flow (TLF), and these vortex structures are related to each other as a feedback loop. The intermittent formation of the vortex ropes leads to the breakdown of the TLV and thus results in the roll-up of the backflow vortex (BFV) due to the radial velocity gradient. The secondary leakage of the BFV locally enhances the TLF jet and affects the formation of the vortex ropes in turn. This feedback loop causes the unsteady behavior of the TLF and has great impacts on the performance and stability of the compressors.
Exceptional points treatment of cavity spectroscopies
Authors: Mukamel Shaul , Li Anqi , Galperin Michael
Published: April 2023

The infrared response of a system of two vibrational modes in a cavity is calculated by an effective non-Hermitian Hamiltonian derived by employing the nonequilibrium Green's function (NEGF) formalism. Degeneracies of the Hamiltonian (exceptional points, EPs) widely employed in theoretical analysis of optical cavity spectroscopies are used in an approximate treatment and compared with the full NEGF. Qualitative limitations of the EP treatment are explained by examining the approximations employed in the calculation.
Rapid observation of dispersion curves in system-on-chip devices
Authors: Wei Zimiao , Chen Yikai , Li Junfeng , Wang Zekai , Wu Xueqin , Zheng Jiale , Liu Xilong , Lan Wenke , Song Yang , Shen Zhonghua , Fu Qiang
Published: April 2023

We have developed a rapid detection instrument to characterize the behavior of light on the surface of devices during light–matter interactions. The equipment enables the non-destructive and real-time observations of the dispersion curves for microstructures, providing the basis for a large number of new planar photonic chip applications. The method is based on the traditional prismatic reflection and makes full use of the grating dispersion capabilities, enabling simultaneous multi-wavelength and multi-angle reflectance measurements over a wide range. This method is beneficial for designing new microstructure devices and brings convenience to delicate microstructure processing. The instruments do not require any mechanical scanning, allowing for rapid acquisition, and the integrated and reusable optics make them easily miniaturized. Additionally, the functionalized design allows for spectral analysis applications, such as far-field spectral measurements. The instrument can also be easily integrated into established microscopic imaging systems, extending their observational characterization capabilities as well as accomplishing dynamic monitoring in proven system-on-a-chip devices.
Measurement of ultrasonic pulse velocity with improved accuracy using automatic threshold error correction
Authors: Piyush  , Dhiman Nitin , Kumar Bishan , Yadav Sanjay , Dubey P. K.
Published: April 2023

Ultrasonic Pulse Velocity (UPV) measurement is extensively used to monitor the strength and health of concrete structures as per American Society for Testing and Materials C 597 – 09. The commercially available UPV measurement systems work on the basis of single threshold detection of the received signal. Therefore, measurement accuracy is affected due to threshold error. The effect is sensitive to the signal amplitude reaching the threshold comparator and, hence, receiver gain. It is observed that a UPV tester operating at 50 kHz to test concrete might generate an error of up to 10% in the ultrasonic transit time measurement of 50 µs. Hence, it is of great concern and needs to be improved. In this article, the UPV measurement circuit capable of detecting and compensating the threshold error is described. The threshold error correction is achieved with the help of two threshold comparators and two hybrid counters. The circuit developed minimizes the threshold error for wide receiver gain. The measurement carried out with the developed system shows significant improvement, having deviations within 100 ns.