bluuebunny/crossref_metadata_2025 huggingface dataset:
Scrutinising the relationship between plage areas and sunspot areas and numbers
Authors: Chatzistergos Theodosios , Ermolli Ilaria , Krivova Natalie A. , Barata Teresa , Carvalho Sara , Malherbe Jean-Marie
Published: September 2022

Context.Studies and reconstructions of past solar activity require data on all magnetic regions on the surface of the Sun (i.e. on dark sunspots as well as bright faculae–plage and network). Such data are also important for understanding the magnetic activity and variability of the Sun and Sun-like stars. The longest available direct faculae–plage datasets are white-light facular and Ca IIK observations going back to 1874 and 1892, respectively. Prior to that time the only direct data available are for sunspots.

Aims.We reassess the relationship between plage areas and sunspot records (areas and numbers) since 1892, to allow reconstructions of facular–plage areas which can be employed for studies going further back in time to the period when solely sunspot observations are available.

Methods.We use the plage areas derived from 38 consistently processed Ca IIK archives as well as the plage area composite based on these archives. The considered archives include both the well-known observatories (e.g. Coimbra, Kodaikanal, Meudon, Mt Wilson), and the less explored observatories (e.g. Kharkiv, Mees, and Upice). These data allow us to study the relationship between plage area and sunspot records (areas and number) over a period of 12 solar cycles and for different bandpasses.

Results.We find the relationship between plage and sunspot areas to be well represented by a power-law function; the relationship between the plage areas and the sunspot number is also best fit with a power-law function. We further find that the relationships depend on the bandwidth and the solar cycle strength. The reconstructions with a power-law relationship are in good agreement with the original plage area series, whereas employment of a cycle-strength-dependent relationship improves the reconstructions only marginally. We also estimate the error in the plage areas reconstructed from the sunspot areas or numbers. Performing the same analysis on other previously published plage area series, usually derived from a single archive with diverse processing techniques, returns different results when using different time series. This highlights the importance of applying a consistent processing to the various archives and demonstrates the uncertainties introduced by using previously published series for studies of past solar activity, including irradiance reconstructions.

Conclusions.Our results have implications for past solar activity and irradiance reconstructions and for stellar activity studies, which sometimes assume a linear dependence between plage and sunspot areas.
Local structural study of α-MoO3 micro-strips using synchrotron X-ray diffraction and X-ray Absorption Spectroscopy at Mo K-edge
Authors: Gawai Umesh , Kamble Shilpa , Kamble Charudipa , Waghmare Yogita , Kulkari Suvarna , Singh Manvendra , Yadav Ashok , Jha Shambhu , Dole Babasaheb
Published: September 2022

The orthorhombic MoO3 micro-strips sample was synthesized using microwave assisted chemical co-precipitation technique. Synchrotron X-ray Diffraction (SXRD) pattern and Rietveld Refinement was used to estimate structural parameter, crystallite size of sample. It reveals that the synthesized sample MoO3 crystallized as an orthorhombic phase. X-ray Absorption Spectroscopy (XAS) measurement, which comprises both X-ray Absorption Near Edge Structure (XANES) and Extended X-ray Absorption Fine Structure (EXAFS) techniques, have been carried out on Mo K-edge to probe the local structure of samples. Local structure is also confirmed from the SXRD and Raman spectra of sample. XAS measurement reveals that the first bond length of Mo-O and Mo-Mo is 1.69 and 3.42 Å in orthorhombic MoO3 respectively. Transmission electron microscopy and SAED patterns showed stripe-like structure and single-crystal formation of MoO3 respectively.
Percutaneous ultrasound-guided ulnar nerve release technique compared to open technique: A cadaveric study
Authors: Mansour Jad , Ghanimeh Joe , Ghersi Abdelhamid , Moutinot Berenice , Coulomb Remy , Kouyoumdjian Pascal , Mares Olivier
Published: September 2022

Objectives: To evaluate the outcomes of a novel percutaneous ultrasound-guided technique for release of ulnar nerve entrapment at the elbow when compared to standard open releaseMethods: One single surgeon performed an ultrasound-guided percutaneous release of the cubital tunnel on a group of five cadaveric elbows and open release on five others. All procedures were timed, and incision lengths were recorded. Meticulous anatomic dissection was then performed to assess the complete release of the carpal tunnel and iatrogenic injuries.Results: No significant difference was found between the two groups in terms of complete release and iatrogenic injury, whereas Operative time was significantly shorter for the US-guided technique. Incomplete releases of the nerve were found only during the first two trials in each group, while the third, fourth, and fifth trials showed a complete ulnar nerve release in both series, highlighting a fast learning curve for both techniques. All of this through a significantly smaller incision in the US-guided technique.Conclusions: This study highlights the similar effects of these two techniques in terms of complete release of the ulnar nerve, with no clear superiority of one over the other in terms of morbidity rate. Both have a fast learning curve for an ultrasound-trained surgeon, with the US-guided technique being a less traumatic and quicker alternative procedure.
Existence of Triple Positive Solutions to a Four-Point Boundary Value Problem of a Fractional Differential Equations
Authors: YANG Liu , SHEN Chunfang , ZHOU Hui
Published: September 2022

In this paper, the existence result of at least triple positive solutions to a boundary value problem of a fractional differential equations is achieved by means of the Avery-Peterson fixed point theorem and the careful analysis of the associate Green's function in which the derivative of unknown function is involved in the nonlinear term explicitly. An example illustrating our main result is given. Our results complement the previous work in the area of the positive solutions of fractional differential equations.
Best Practice Guideline – Empfehlungen der DEGUM zur Durchführung und Beurteilung der Mammasonografie – TEIL I – Untersuchungstechnik, Ultraschall-DEGUM-Kriterien und deren Dokumentation
Authors: Bader Werner , Vogel-Minea Claudia Maria , Blohmer Jens-Uwe , Duda Volker , Eichler Christian , Fallenberg Eva , Farrokh André , Golatta Michael , Gruber Ines , Hackelöer Bernhard-Joachim , Heil Jörg , Madjar Helmut , Marzotko Ellen , Merz Eberhard , Müller-Schimpfle Markus , Mundinger Alexander , Ohlinger Ralf , Peisker Uwe , Schäfer Fritz K. W. , Schulz-Wendtland Ruediger , Solbach Christine , Warm Mathias , Watermann Dirk , Wojcinski Sebastian , Hahn Markus
Published: September 2022

Die Mammasonografie hat sich seit vielen Jahren neben der Mammografie als wichtige Methode zur Abklärung von Brustbefunden etabliert. Problematisch bleiben jedoch Unterschiede in der Interpretation von Befunden 1
2. Dies vermindert die diagnostische Treffsicherheit der Sonografie nach Detektion eines Befundes, erschwert die interdisziplinäre Kommunikation und den Vergleich von wissenschaftlichen Arbeiten 3. Das American College of Radiology (ACR) hatte 1999 eine Arbeitsgruppe gebildet (International Expert Working Group), die auf der Basis der langjährig etablierten BI-RADS-Klassifizierung von mammografischen Befunden und unter Berücksichtigung von Literaturdaten eine ähnliche Einteilung für die Ultraschalluntersuchung erarbeitet hatte 4. Aufgrund inhaltlicher Unterschiede hatte die DEGUM bereits 2006 einen eigenen BI-RADS-analogen Kriterienkatalog publiziert 3. Die aktuelle 5. Edition des ACR-BI-RADS-Katalogs offenbart neben diesen weiterhin bestehenden inhaltlichen Unterschieden zudem das Problem der formalen Lizenzierung, wird aber inhaltlich von der DEGUM als weiteres Befundbeschreibungs- und Dokumentationssystem anerkannt.

Der Arbeitskreis Mammasonografie der DEGUM beabsichtigt mit der „Best Practice Guideline“, den senologisch tätigen Kolleginnen und Kollegen einen aktuellen Dignitätskriterien- und Befundungskatalog sowie „Best Practice“-Empfehlungen zu den verschiedenen Modalitäten an die Hand zu geben.
Persönlichkeitsstörungen und Sucht
Authors: Walter Marc , Pichler Eva-Maria
Published: September 2022

In der Klinik kommen Suchterkrankungen bei Patient:innen mit Persönlichkeitsstörungen häufig vor. Bei etwa jeder zweiten Persönlichkeitsstörung kann eine komorbide Suchterkrankung diagnostiziert werden. Bei Patient:innen mit einer Drogenabhängigkeit scheint eine komorbide Persönlichkeitsstörung etwas häufiger als bei der Alkoholabhängigkeit aufzutreten. Eine besonders häufige Assoziation wurde zwischen Cluster-B-Persönlichkeitsstörungen (DSM-5) und einer komorbiden Suchterkrankung gefunden.

In der Behandlung der Komorbidität sollte der Grundsatz gelten, dass beide Störungsbilder beachtet und gemeinsam behandelt werden. Ist die Persönlichkeitsproblematik im Vordergrund, werden insbesondere störungsspezifische Psychotherapien mit Erfolg angewandt (z. B. Dialektisch-Behaviorale Therapie DBT, Übertragungsfokussierte Therapie TFP, Mentalisierungsbasierte Therapie MBT, Schematherapie). Ist die Suchtproblematik klinisch führend, kommen derzeit neben pharmakologischen Behandlungen vorrangig suchtspezifische Interventionen, wie die Motivierende Gesprächsführung oder die Rückfallprävention zum Einsatz. Bei evidenzbasierter Behandlung ist die Prognose wahrscheinlich günstiger als dies in Studien bisher berichtet wurde.
New Computerized Elbow and Forearm Clinical Scores
Authors: Herzberg Guillaume , Burnier Marion , Ly Lyliane , Nakamura Toshiyatsu
Published: September 2022

Background Current elbow clinical scores are scarce with limited comparability between them. None of them are computerized yet. There is no forearm clinical score assessing all anatomical components of forearm disorders such as the Essex-Lopresti injuries. The aims of this paper were to present new computerized elbow and forearm clinical scores.

Methods These new computerized elbow and forearm clinical scores include four clinical criteria: pain, function, active range of motion and muscle strength. To each criterion is given a numerical value among 5 grades. The weight of each criterion is equivalent so that patient's and physician's related scores are equally balanced.

Results Clinical scores components are automatically included into diamond-shape graphs and tables that can be directly exported into PowerPoint presentations for demonstration and comparison purposes.

Discussion These user-friendly updatable clinical elbow and forearm scores are based on four classic clinical criteria, pain, function, motion, and strength that are expressed into grades. They were designed to evaluate any osteoarticular elbow or forearm disorder regardless of the etiology. These scores are open since they may be modified in future versions.
Reducing Tourniquet Pressures in Hand Surgery: Are Lower Pressures as Effective?
Authors: Azad Ali , Sager Brian , Gupta Salil , Ayalon Omri , Paksima Nader
Published: September 2022

Background Pneumatic tourniquets are widely used in hand surgery. Elevated pressures can be associated with complications, and thus, guidelines based on patient-specific tourniquet pressures have been recommended. The primary aim of this study was to determine whether lower tourniquet values based on systolic blood pressure (SBP) could be effectively applied in upper extremity surgery.

Methods A prospective case series of 107 consecutive patients undergoing upper extremity surgery with use of a pneumatic tourniquet was performed. Tourniquet pressure used was based on the patient's SBP. The tourniquet was inflated based on our predetermined guidelines: 60 mm Hg was added for SBP < 130 mm Hg, 80 mm Hg for SBP between 131 and 190 mm Hg, and 100 mm Hg for SBP > 191 mm Hg. The outcome measures included intraoperative tourniquet adjustment, surgeon-rated quality of bloodless operative field and complications.

Results The mean tourniquet pressure was 183 ± 26 mm Hg with a mean tourniquet time of 34 minutes (range: 2–120 minutes). There were no instances of intraoperative tourniquet adjustment. The surgeon-rated quality of bloodless operative field was excellent in all patients. No complications were associated with the use of a tourniquet.

Conclusion Tourniquet inflation pressure based on SBP is an effective method to provide a bloodless surgical field in upper extremity surgery at significantly lower inflation pressures than are the current standards.
Risk Factors Associated with Adverse Outcomes after Ablative Surgery for Lymphedema
Authors: Kuruvilla Annet S. , Shroyer Annie Laurie W. , Li Xiaoning , Yang Jie , Mulay Sagar R. , Agha Sohaib M. , Bellis Raymond M. , Kohli Harmehar K. , Tannous Henry J. , Krajewski Aleksandra
Published: September 2022

Background Postmastectomy breast cancer lymphedema poses an important health threat. Historically, physical therapy was the exclusive treatment option. More recently, lymphedema surgery has revolutionized care. As a first-in-kind, multicenter report, the postmastectomy breast cancer patients' risk factors associated with postlymphedema ablative surgical outcomes were documented.

Methods Using the New York Statewide Planning and Research Cooperative System database from 2010 to 2018, multivariable models identified the postmastectomy breast cancer lymphedema surgical patients' characteristics associated with major adverse outcomes and mortality.

Results Of 65,543 postmastectomy breast cancer patients, 1,052 lymphedema surgical procedures were performed including 393 (37.4%) direct excisions and 659 (63.6%) liposuctions. Direct excision and liposuction surgical patients had median ages of 58 and 52 years, respectfully (p < 0.001). Although a 30-day operative mortality was rare (0.3%, all direct excisions), major adverse outcomes occurred in 154 patients (28.5% direct excision; 6.4% liposuction; p < 0.0001). Multivariable clinical outcomes model identified that patients with higher Elixhauser's score, renal disease, emergent admissions, and direct excision surgery had higher incidences of adverse outcomes (all p < 0.01). For those patients with 30-day readmissions (n = 60), they were more likely to have undergone direct excision versus liposuction (12.5 vs. 1.7%; p < 0.0001). The important risk factors predictive of future cellulitis/lymphangitis development included diabetes mellitus, Medicaid insurance, renal disease, prior cellulitis/lymphangitis, chronic obstructive pulmonary disease (COPD), and chronic steroid use (all p < 0.01).

Conclusion Lymphedema surgery carries a favorable risk profile, but better understanding the “high-risk” patients is critical. As this new era of lymphedema surgery progresses, evaluating the characteristics for adverse postoperative outcomes is an important step in our evolution of knowledge.
Surgical Management of Patellar Tendinopathy Results in Improved Outcomes and High Rates of Return to Sport: A Systematic Review
Authors: Cognetti Daniel J. , Sheean Andrew J. , Arner Justin W. , Wilkerson Devaughn , Bradley James P.
Published: September 2022

Although the majority of patients with patellar tendinopathy (PT) can be treated nonoperatively, operative management may be indicated for recalcitrant cases. While several surgical techniques have been described, there is limited understanding of postoperative outcomes and expectations regarding return to activity and sport. The purpose of this study was to characterize the clinical outcomes associated with the surgical management of PT with an emphasis on return to sport (RTS) rates. We hypothesized that surgical management would lead to clinically important improvements in patient-reported outcomes (PROs) with high rates of RTS and RTS at the same level. A comprehensive search of the PubMed, Medline, and Embase databases was performed in December 2020. Level of evidence studies I through IV, investigating results of surgical management for PT (PRO, functional outcomes, pain, and/or RTS), were included. The search was performed in accordance with the Preferred Reported Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Forty clinical studies reporting on surgery for PT satisfied inclusion criteria, with 1,238 total knees undergoing surgery for PT. A comparison of pre- and postoperative Victorian Institute of Sport Assessment, patellar tendon (VISA-P) scores (mean difference: 41.89, p < 0.00001), Lysholm scores (mean difference: 41.52, p < 0.00001), and visual analogue scale (VAS) pain scores (mean difference: 5, p < 0.00001) demonstrated clinically and statistically significant improvements after surgery. The overall RTS rate following operative management was 89.8% (95% confidence interval [CI]: 86.4–92.8, I 2 = 56.5%) with 76.1% (95% CI: 69.7.5–81.9, I 2 = 76.4%) of athletes returning to the same level of activity. Surgery for PT provides meaningful improvement in patient reported outcomes and pain while allowing athletes to RTS at high rates with levels of participation similar to that of preinjury. Comparative studies of open and/or arthroscopic surgery are still limited but current evidence suggests better rates of RTS for arthroscopic surgery compared with open surgery. This is a systematic review of level-I to -IV studies.
Ground state solution for a nonlinear fractional magnetic Schrödinger equation with indefinite potential
Authors: Cui Na , Sun Hong-Rui
Published: September 2022

This paper is concerned with the following nonlinear fractional Schrödinger equation with a magnetic field: ε2s(−Δ)A/εsu+V(x)u=f(|u|2)u inRN, where ɛ > 0 is a parameter, s ∈ (0, 1), N ≥ 3, V:RN→R and A:RN→RN are continuous potentials, and V may be sign-changing; the nonlinearity is superlinear with subcritical growth but without satisfying the Ambrosetti–Rabinowitz condition. Based on the Nehari manifold method, concentration-compactness principle, and variational methods, we prove the existence of a ground state solution for the above equation when ɛ is sufficiently small. Our results improve and extend the result of Ambrosio and d’Avenia [J. Differ. Equations 264, 3336–3368 (2018)].
Determination of the background doping polarity for unintentionally doped AlGaAsSb and AlInAsSb avalanche photodiodes on InP substrates
Authors: Schwartz M. , Kodati S. H. , Lee S. , Jung H. , Chen D. , Grein C. H. , Ronningen T. J. , Campbell J. C. , Krishna S.
Published: September 2022

Background doping polarity is a critical design parameter for the performance of many optoelectronic devices, including avalanche photodiodes. We have applied a technique by using capacitance–voltage (CV) measurements on double mesa structures with a p-i-n or n-i-p homojunction to determine the background polarity type of the unintentionally doped intrinsic region. Because CV measurements scale with the size of the mesa, they support design flexibility in producing variable-sized top and bottom mesa diameters. In this work, we grew, fabricated, and tested AlGaAsSb and AlInAsSb random alloy double mesa p-i-n structures and undertook CV measurements at 295, 150, and 77 K. It was found that the capacitance varied with the top mesa diameter for both material systems, and not the bottom mesa diameter, indicating that the unintentionally doped intrinsic region is n-type in nature.
Angle-resolved high-order harmonics in wurtzite-type ZnO
Authors: Li Wenkai , Liu Zhe , Shao Beijie , Qian Junyu , Li Yanyan , Peng Yujie , Leng Yuxin
Published: September 2022

High-order harmonics in solids provide a method of analyzing the intraband and interband dynamics of a solid driven by an ultrafast laser. This study analyzed the contributions of intraband and interband dynamics based on angle-resolved high-order harmonics. According to the simulations and experiments, we found that the angular divergences of the harmonics have an evident boundary at the bandgap when the laser is polarized along the asymmetric direction, which is primarily invoked by the interplay of an interband transition and an intraband electron movement, and the intraband and interband dynamics have different sensitivities of the spatial phase of driving laser.
Mechanical characterization of piezoelectric materials: A perspective on deformation behavior across different microstructural length scales
Authors: Kathavate V. S. , Prasad K. Eswar , Kiran Mangalampalli S. R. N. , Zhu Yong
Published: September 2022

Piezoelectric materials (PEMs) find a wide spectrum of applications that include, but are not limited to, sensors, actuators, semiconductors, memory devices, and energy harvesting systems due to their outstanding electromechanical and polarization characteristics. Notably, these PEMs can be employed across several length scales (both intrinsic and extrinsic) ranging from mesoscale (bulk ceramics) to nanoscale (thin films) during their applications. Over the years, progress in probing individual electrical and mechanical properties of PEM has been notable. However, proportional review articles providing the mechanical characterization of PEM are relatively few. The present article aims to give a tutorial on the mechanical testing of PEMs, ranging from the conventional bulk deformation experiments to the most recent small-scale testing techniques from a materials science perspective. The advent of nanotechnology has led materials scientists to develop in situ testing techniques to probe the real-time electromechanical behavior of PEMs. Therefore, this article presents a systematic outlook on ex situ and in situ deformation experiments in mechanical and electromechanical environments, related mechanical behavior, and ferroelectric/elastic distortion during deformation. The first part provides significant insights into the multifunctionality of PEM and various contributing microstructural length scales, followed by a motivation to characterize the mechanical properties from the application's point of view. In the midst, the mechanical behavior of PEM and related mechanical characterization techniques (from mesoscale to nanoscale) are highlighted. The last part summarizes current challenges, future perspectives, and important observations.
Two competing simplicial irreversible epidemics on simplicial complex
Authors: Li Wenjie , Nie Yanyi , Li Wenyao , Chen Xiaolong , Su Sheng , Wang Wei
Published: September 2022

Higher-order interactions have significant implications for the dynamics of competing epidemic spreads. In this paper, a competing spread model for two simplicial irreversible epidemics (i.e., susceptible–infected–removed epidemics) on higher-order networks is proposed. The simplicial complexes are based on synthetic (including homogeneous and heterogeneous) and real-world networks. The spread process of two epidemics is theoretically analyzed by extending the microscopic Markov chain approach. When the two epidemics have the same 2-simplex infection rate and the 1-simplex infection rate of epidemic A (λA) is fixed at zero, an increase in the 1-simplex infection rate of epidemic B (λB) causes a transition from continuous growth to sharp growth in the spread of epidemic B with λB. When λA>0, the growth of epidemic B is always continuous. With the increase of λA, the outbreak threshold of epidemic B is delayed. When the difference in 1-simplex infection rates between the two epidemics reaches approximately three times, the stronger side obviously dominates. Otherwise, the coexistence of the two epidemics is always observed. When the 1-simplex infection rates are symmetrical, the increase in competition will accelerate the spread process and expand the spread area of both epidemics; when the 1-simplex infection rates are asymmetrical, the spread area of one epidemic increases with an increase in the 1-simplex infection rate from this epidemic while the other decreases. Finally, the influence of 2-simplex infection rates on the competing spread is discussed. An increase in 2-simplex infection rates leads to sharp growth in one of the epidemics.
Effect of heavy inert ion strikes on cell density-dependent profile variation and distortion during the etching process for high-aspect ratio features
Authors: Kwon Hyoungcheol , Won Imhee , Han Songhee , Yu Dong-Hun , Kwon Deuk-Chul , Im Yeon Ho , Iza Felipe , Oh Dongyean , Park Sung-Kye , Cha Seonyong
Published: September 2022

Vertical scaling technique faces a physical limitation in 3D NAND device fabrication, even assuming superior etching technology. Another promising scaling technique to increase the storage density is lateral scaling, which increases the number of holes between slit and slit from four to nine and above. However, unpredictable small critical dimension, feature-to-feature variation, and distortion occur. To elucidate the profile deteriorations induced by the lateral scaling, we analyzed the effect of the angular etching yield dependency of the incident ion fluxes into a given feature using the multiscale technology computer-aided design methodology. As one of the inherent features of the gas, incident angle θmax in which the sputtering yield achieves its maximum value is a crucial factor for analyzing and modeling etching profiles. Moreover, the impact of the heavy inert ion strikes on the unpreferred etching profiles was investigated. In this study, the synergy of lower energy ions, larger fluxes, and larger θmax of heavy inert ions decrease the feature-to-feature variation, reducing hard mask distortion without the etch rate reduction.
Quantifying electron temperature distributions from time-integrated x-ray emission spectra
Authors: MacDonald M. J. , Liedahl D. A. , Brown G. V. , Åberg D. , Cliche D. T. , Foord M. E. , Grabowski P. E. , Heeter R. F. , Hoarty D. J. , London R. A. , Martin M. E. , Nilsen J. , Patel M. V. , Scott H. A. , Shepherd R. , Whitley H. D. , Widmann K.
Published: September 2022

K-shell x-ray emission spectroscopy is a standard tool used to diagnose the plasma conditions created in high-energy-density physics experiments. In the simplest approach, the emissivity-weighted average temperature of the plasma can be extracted by fitting an emission spectrum to a single temperature condition. It is known, however, that a range of plasma conditions can contribute to the measured spectra due to a combination of the evolution of the sample and spatial gradients. In this work, we define a parameterized model of the temperature distribution and use Markov Chain Monte Carlo sampling of the input parameters, yielding uncertainties in the fit parameters to assess the uniqueness of the inferred temperature distribution. We present the analysis of time-integrated S and Fe x-ray spectroscopic data from the Orion laser facility and demonstrate that while fitting each spectral region to a single temperature yields two different temperatures, both spectra can be fit simultaneously with a single temperature distribution. We find that fitting both spectral regions together requires a maximum temperature of 1310−70+90 eV with significant contributions from temperatures down to 200 eV.
UV-A to UV-B electroluminescence of core-shell GaN/AlGaN wire heterostructures
Authors: Grenier Vincent , Finot Sylvain , Valera Lucie , Eymery Joël , Jacopin Gwénolé , Durand Christophe
Published: September 2022

Core-shell GaN/AlGaN multiple quantum wells (MQWs) embedded in a p–n junction are integrated on the upper part of GaN microwires grown by silane-assisted metal organic vapor phase epitaxy. Dispersed wires are then contacted by electron beam induced deposition for fabrication of single wire UV-LED devices. Rectifying diode-like behavior is first demonstrated for both GaN and GaN/AlGaN p-n junctions without a MQW active region. A weak leakage current in the GaN/AlGaN core-shell heterostructure is attributed to an additional conduction path along wire sidewalls. Electroluminescence at 340 nm in UV-A is demonstrated using a GaN (2.6 nm)/Al0.3Ga0.7N (3 nm) heterostructure embedded in a GaN/Al0.3Ga0.7N p–n junction. This value is even decreased to 310 nm by reducing the well thickness to 0.9 nm and increasing the Al-content of barriers (up to 60%) integrated in the GaN/Al0.3Ga0.7N p–n junction. This work demonstrates UV-B emission based on single wire core-shell UV-LEDs.
Identification of defects in the inner layers of composite components based on capacitive sensing
Authors: Sun Yurong , Zhang Yuyan , Wen Yintang
Published: September 2022

This paper describes the development and validation of a rapid internal defect detection method for multilayer composite components. Coplanar array capacitive imaging is based on electrical capacitance tomography, in which all electrodes are arranged in a single plane. The coplanar array capacitive sensor system is based on the capacitive edge effect and reconstructs the dielectric distribution in the sensitive area by measuring the capacitance of the sensor. A 4 × 3 array of coplanar electrode sensors is established and used to image the defects in the inner layers of multilayer composite components. Using a 3D model of the sensor and the sensitivity field, the variation pattern of the sensitivity field is analyzed. By placing different objects into the sensitivity area of the system, changes in the dielectric constant can be observed. Multilayer composite components with void defects are placed in the measurement area for defect detection. The dielectric distribution is visualized by reconstruction algorithms from the capacitance data and sensitivity field data. The results show that the imaging system based on a coplanar array capacitive sensor can reproduce the location of defects and realize the nondestructive testing of complex multilayer composite components.
Crises and chaotic scattering in hydrodynamic pilot-wave experiments
Authors: Choueiri George , Suri Balachandra , Merrin Jack , Serbyn Maksym , Hof Björn , Budanur Nazmi Burak
Published: September 2022

Theoretical foundations of chaos have been predominantly laid out for finite-dimensional dynamical systems, such as the three-body problem in classical mechanics and the Lorenz model in dissipative systems. In contrast, many real-world chaotic phenomena, e.g., weather, arise in systems with many (formally infinite) degrees of freedom, which limits direct quantitative analysis of such systems using chaos theory. In the present work, we demonstrate that the hydrodynamic pilot-wave systems offer a bridge between low- and high-dimensional chaotic phenomena by allowing for a systematic study of how the former connects to the latter. Specifically, we present experimental results, which show the formation of low-dimensional chaotic attractors upon destabilization of regular dynamics and a final transition to high-dimensional chaos via the merging of distinct chaotic regions through a crisis bifurcation. Moreover, we show that the post-crisis dynamics of the system can be rationalized as consecutive scatterings from the nonattracting chaotic sets with lifetimes following exponential distributions.
Simultaneous application of photon Doppler velocimetry and coherent backscattering for probing ejecta from shock-loaded samples
Authors: Andriyash A. V. , Ismailov Sh. M. , Kamenev V. G. , Kaplukov G. V. , Kondratev A. N. , Kubasov P. V. , Kuratov S. E. , Rogozkin D. B. , Tikhov A. A. , Tur I. V. , Shubin A. S. , Shubin S. A. , Yaroschuk P. N.
Published: September 2022

We present the results of experiments on simultaneous probing of a shock-loaded layer of aluminum oxide particles by the methods of photon Doppler velocimetry (PDV) and coherent backscattering (CBS). The measurements of the angular profiles of CBS from a dynamically expanding medium are reported for the first time. The powder of particles was applied to the surface of an explosively driven steel plate. The particle velocities ranged from 0.9 to 1.3 km/s. The main characteristics of the cloud of ejected particles (the areal density, mass–velocity distribution, etc.) are recovered from the PDV and CBS probing data using an approach based on theoretical modeling of the measurement results with the transport equation. By varying the parameters of the particle cloud (the transport optical thickness and the parameters of the initial velocity distribution), it is managed to fit the dynamics of the calculated Doppler spectra and CBS angular profiles to the data of measurements in given time intervals and, thereby, recover the values of these parameters. As applied to the diagnostics of ejecta from shock-loaded samples, the CBS method is shown to provide independent data on the spatial distribution of particles over the cloud thickness. The presented results demonstrate that the joint application of PDV- and CBS-based channels of measurements to ejecta diagnostics makes it possible to halve the error in recovering the ejecta parameters compared to using PDV alone.
Ultraviolet photodissociation of Mg+–NO complex: Ion imaging of a reaction branching in the excited states
Authors: Ito Yuri , Nakashima Yuji , Okutsu Kenichi , Nakano Motoyoshi , Misaizu Fuminori
Published: September 2022

Ultraviolet photodissociation processes of gas phase Mg+–NO complex were studied by photofragment ion imaging experiments and theoretical calculations for excited electronic states. At 355 nm excitation, both Mg+ and NO+ photofragment ions were observed with positive anisotropy parameters, and theoretical calculations revealed that the two dissociation channels originate from an electronic transition from a bonding orbital consisting of Mg+ 3s and NO π* orbitals to an antibonding counterpart. For the NO+ channel, the photofragment image exhibited a high anisotropy (β = 1.53 ± 0.07), and a relatively large fraction (∼40%) of the available energy was partitioned into translational energy. These observations are rationalized by proposing a rapid dissociation process on a repulsive potential energy surface correlated to the Mg(1S) + NO+(1Σ) dissociation limit. In contrast, for the Mg+ channel, the angular distribution was more isotropic (β = 0.48 ± 0.03) and only ∼25% of the available energy was released into translational energy. The differences in the recoil distribution for these competing channels imply a reaction branching on the excited state surface. On the theoretical potential surface of the excited state, we found a deep well facilitating an isomerization from bent geometry in the Franck–Condon region to linear and/or T-shaped isomer. As a result, the Mg+ fragment was formed via the structural change followed by further relaxation to lower electronic states correlated to the Mg+(2S) + NO(2Π) exit channel.
Electrically tunable spectral response in vertical nanowire arrays
Authors: Xia Hui , Liu Yaqian , Wang Hailu , Li Tianxin , Tong Zhongying , Chen Xiren , Chen Pingping , Hu Weida , Lu Wei
Published: September 2022

The semiconductor nanowire (NW) array promises a high photoconductive-gain as well as an enhanced light-absorption in optoelectronic applications. However, to date, the two kinds of advantages are always consuming each other, leading to a low global income. In this work, we show a feasible route to balance the electric gain and the light absorption efficiency. It is accomplished by an inverse injection of photocarriers into NW (from the tip to the bottom of NW or in the opposite direction), which will activate the photoconductive gain in maximal degree. Experimentally, the responsivity reaches up to ∼200 A/W. The spectral response of the GaAs nanowire-array detector is proven to be bias-voltage controlled, allowing it to work at visible or shortwave-infrared enhanced modes. Also, the photoresponse carries on the wavelength information of the incident light, thus, can be used to discriminate monochromatic lights from each other. Together, these findings depict a full image of the photoresponse process in the vertical nanowire array. It might pave a way for the design and fabrication of subwavelength optoelectronic devices.
Temperature-dependent critical spin-orbit field for orthogonal switching in antiferromagnets
Authors: Rama-Eiroa R. , Otxoa R. M. , Atxitia U.
Published: September 2022

The discovery of current-induced spin–orbit torque (SOT) orthogonal reorientation, also known as orthogonal switching, of metallic Mn2Au and CuMnAs has opened the door for ultrafast writing of an antiferromagnet (AFM). A phenomenological theory predicts that the minimum field necessary for SOT switching—critical field—for ultrashort pulses increases inversely proportional to the pulse duration, thereby limiting the use of ultrafast stimulus as driving force for switching. We explore the possibility that by varying the working temperature, the critical field reduces enabling orthogonal switching in response to ultrashort pulses. To do so, we extend the previous theory to finite temperature and show that the critical field for orthogonal switching strongly depends on temperature. We determine how the temperature dependence of the critical field varies as a function of the pulse duration. For long pulses, the temperature dependence of the critical field is determined by the anisotropy field, and for ultrashort pulses, it is determined by the characteristic frequency of the AFM. We show that the short and long pulse duration limits for the critical field can be connected by an analytical expression.
An insight into the interaction between the in-plane and out-of-plane responses of a catenary flexible riser
Authors: Gao Yue , Zhu Hongjun , Li Quanhua , Hu Jie , Zhou Tongming , Shao Yongbo
Published: September 2022

Nonlinear dynamic response of catenary flexible risers excited by ocean currents is the main reason for fatigue failures. In this work, a series of experiments are conducted to improve the understanding of the intrinsic relationship between the in-plane and out-of-plane responses of a catenary flexible riser subjected to a sheared current in the depth-averaged Reynold number range of 150–1880. It is found that the interaction between the in-plane and out-of-plane responses is sensitive to the reduced velocity. Four patterns are identified, including the weak coupling, the partial coupling, the strong coupling, and the strong coupling+. The interaction is negligible at low reduced velocities. In contrast, when the reduced velocity is sufficiently large, the in-plane dominant frequency coincides with the out-of-plane one, signifying a strong coupling. As the reduced velocity increases, only a part of the riser possesses the same dominant frequency in the in-plane and out-of-plane directions, termed partial coupling. At higher reduced velocities, the coupled pipe section is shortened and the interaction is finally attenuated.
Estimating wind velocity and direction using sparse sensors on a cylinder
Authors: Caverly D. , Nedić J.
Published: September 2022

Using finite pressure measurements on a cylinder, we are able to estimate both the oncoming wind speed and direction of uniform flow over a cylinder at Reynolds numbers 20 000<Re<120 000. While reduced-order methods, such as proper orthogonal decomposition with QR factorization, require at least nine sensors to estimate the oncoming wind speed and direction with <10% error, other methods, such as probabilistic approaches or curve-fitting, can achieve similar results with as few as five sensors. A utility function, based on the Kullback–Leibler divergence, is used to determine the locally optimal location of the sensors to accurately estimate inlet conditions. It was found that sensor arrangement also plays a significant role, with unevenly distributed sensors being preferable than evenly distributed sensors. These techniques, when paired with existing flow field estimation approaches, allow the user to predict the surrounding flow field from any oncoming direction.
Hydrodynamic performance of dual-chamber Oscillating Water Column array under oblique waves
Authors: Li Yang , Zhao Xuanlie , Zou Qingping , Geng Jing
Published: September 2022

A multiple Oscillating Water Column (OWC) device may provide better wave absorption over a wider frequency bandwidth than a single-chamber OWC due to multiple resonances. The scattering and radiation of three-dimensional oblique waves by an array of periodic dual-chamber OWCs are considered here along a coastal cliff. A semi-analytical model was developed based on potential flow theory and matching eigenfunction method to investigate the oblique wave interaction with a dual-chamber OWC array system. The velocity singularity at the tip of a chamber wall is resolved by introducing the Galerkin technique to accelerate the convergence. The semi-analytical solution is verified by the Haskind relation and energy conservation law. Hydrodynamics of the proposed system and the influence of wave and geometric parameters were investigated. Theoretical results indicate that a dual-chamber OWC array has a broader capture bandwidth than a single-chamber OWC array for both normal and oblique waves. The presence of the along-shore and cross-shore sloshing resonance is theoretically confirmed in each subchamber of OWC unit, which decreases the hydrodynamic efficiency and increases the wave reflection drastically. Although the wave loading on the chamber wall decreases with increasing incident wave angle θ, the wave loading on chamber/partition wall may increase sharply due to sloshing resonance at critical frequency kc. To our knowledge, this is the first attempt to investigate the hydrodynamics of dual-chamber OWC array under oblique waves. The present theoretical results indicate the potential risks of structural damage and total wave reflection due to sloshing resonance, which should be an important design consideration.
Particle clusters within inertial vortical flows in micro-cross-shaped channels
Authors: Zhang Wei , Shi Zhe-Hang , Li Wei-Feng , Liu Hai-Feng , Wang Fu-Chen
Published: September 2022

Inertial vortical flows can be used as a tool to capture and manipulate microparticles, vesicles, or cells. Current work follows our previous report [Zhang et al., Int. J. Multiphase Flow 150, 104030 (2022)] to study the flow of diluted particle suspension in micro-cross-shaped channels at 20 < Re < 500 by micro-laser-induced fluorescence and high-speed photography. Effects of inlet aspect ratio (α) and Reynolds numbers (Re) on flow regimes and particle capture were studied. Numerical simulation was adopted to reveal vortex breakdown dynamics associated with particle capture. For each α, as Re increases, segregated flows, steady engulfment flows, vortex shedding flows, and unsteady engulfment flows appear in turns. Experimental results demonstrate a flow-induced, Re and α-dependent particle cluster within steady engulfment and vortex shedding flows, and an increase in α decreases the onset Re of the cluster. With increasing Re, an interesting oscillation of the cluster is established, which triggers the escape of captured particles. Simulation results show that the oscillation frequencies of the cluster and fluid are comparable. Although isolated particles display brief recirculating paths under unsteady engulfment flows, the particle cluster disappears.
Coupled local mode method for simulating vibrational spectroscopy
Authors: Hanson Matthew D. , Corcelli Steven A.
Published: September 2022

Experimental and theoretical studies have highlighted protonated water clusters (PWCs) as important models of the excess proton in aqueous systems. A significant focus has been characterizing the spectral signatures associated with different excess proton solvation motifs. Accurate vibrational frequency calculations are crucial for connecting the measured spectra to the structure of PWCs. In this paper, we extend and characterize a coupled local mode (CLM) approach for calculating the infrared spectra of PWCs using the H+(H2O)4 cluster as a benchmark system. The CLM method is relatively low cost and incorporates the anharmonicity and coupling of OH vibrations. Here, we demonstrate the accuracy of the technique compared to experiments. We also illustrate the dependence of calculated spectral features on the underlying electronic structure theory and basis sets used in the local mode frequency and coupling calculations.
Valence molecular orbitals and cationic structures of 2-fluoropyridine by high-resolution ion spectroscopy and Franck–Condon fitting
Authors: Lee Yu Ran , Kwon Chan Ho
Published: September 2022

The alteration of the valence molecular orbitals’ ordering of halopyridine molecules, by the introduction of a halogen atom(s) as substituent on the pyridine ring, has spurred an extensive interest for their investigation. Herein, the effect of a fluorine substituent on the two outermost orbitals of pyridine was elucidated by investigating the photoionization dynamics of 2-fluoropyridine (2-FP), considering that the geometrical changes with respect to the neutral geometry induced by adiabatic ionic transition affect the vacuum ultraviolet mass-analyzed threshold ionization (VUV-MATI) spectrum. The adiabatic ionization energy associated with the 0-0 band on the measured high-resolution VUV-MATI spectrum was determined to be 9.6702 ± 0.0004 eV (77 995 ± 3 cm−1), which differs considerably from the 9.401 eV by two-color ionization spectroscopy. Franck–Condon simulation of the MATI spectrum corresponded quantitatively with the experimental results. Interestingly, among the forbidden transitions under CS symmetry, an out-of-plane ring-bending mode resulting from the warped cationic structure of 2-FP with C1 symmetry was discovered. Rigorously, among the unassigned peaks, the first prominent peak at 78 532 cm−1 should rather be assigned as the origin of the excited electronic state (D1) of the 2-FP cation, in accordance with time-dependent density functional theory calculations. Natural bond orbital analysis led to the conclusion that such observations could be induced by electron removal from the highest occupied molecular orbital (HOMO) consisting of the π orbital of the pyridine ring and lone-pair orbital of the fluorine atom or from the HOMO-1 of the molecular non-bonding orbitals, to generate the two proximate electronic states of the cation.
Preserving entanglement in a solid-spin system using quantum autoencoders
Authors: Zhou Feifei , Tian Yu , Song Yumeng , Qiu Chudan , Wang Xiangyu , Zhou Mingti , Chen Bing , Xu Nanyang , Lu Dawei
Published: September 2022

Entanglement, as a key resource for modern quantum technologies, is extremely fragile due to the decoherence. Here, we show that a quantum autoencoder, which is trained to compress a particular set of quantum entangled states into a subspace that is robust to decoherence, can be employed to preserve entanglement. The training process is based on a hybrid quantum-classical approach to improve the efficiency in building the autoencoder and reduce the experimental errors during the optimization. Using nitrogen-vacancy centers in diamond, we demonstrate that the entangled states between the electron and nuclear spins can be encoded into the nucleus subspace, which has much longer coherence time. As a result, lifetime of the Bell states in this solid-spin system is extended from 2.22 ± 0.43 μs to 3.03 ± 0.56 ms, yielding a three orders of magnitude improvement. The quantum autoencoder approach is universal, paving the way of utilizing long lifetime nuclear spins as immediate-access quantum memories in quantum information tasks.