bluuebunny/crossref_metadata_2025 huggingface dataset:
Long-term Outcomes of PreserFlo MicroShunt versus XEN45 Gel Stent in Open-Angle Glaucoma
Authors: Nobl Matthias , Freissinger Sigrid , Rudolph Katrin , Vounotrypidis Efstathios , Kassumeh Stefan , Priglinger Siegfried , Mackert Marc Julian
Published: September 2023

Purpose To compare two glaucoma drainage devices with subconjunctival filtration (MicroShunt and XEN) for open-angle glaucoma (OAG), with respect to effectiveness and safety.

Patients and Methods This is a single center, retrospective, interventional study. In total, 106 eyes of 95 patients with OAG underwent surgery. Of these patients, 51 eyes of 45 patients received a MicroShunt implantation and 55 eyes of 50 patients received an XEN implantation. Failure was defined as an intraocular pressure (IOP) lower than 5 or higher than 17 mmHg at the end of follow-up after 2 years, the need for surgical revision, secondary glaucoma surgery, or loss of light perception. Outcome was rated as complete success or qualified success, depending on whether it was achieved with or without anti-glaucomatous medications. Postoperative complications and interventions were also documented for both groups.

Results In the MicroShunt group, mean IOP decreased from 20.6 ± 7.5 mmHg at baseline to 13.0 ± 3.9 mmHg (p < 0.0001) after 2 years. In the XEN group, mean IOP was lowered from 22.5 ± 7.9 mmHg to 13.5 ± 4.2 mmHg (p < 0.0001). In both groups, the mean number of medications was significantly reduced (MicroShunt 2.7 ± 1.2 to 0.9 ± 2.5; p < 0.0001 vs. XEN 3.2 ± 0.9 to 1.1 ± 1.5; p < 0.0001). In regard to success rates, 37% of MicroShunt patients achieved complete success and 57% qualified success at the end of follow-up. In the XEN group, rates were 25 and 45%, respectively. Patient demographics differed between the two groups with respect to age (MicroShunt 72.8 ± 8.7 vs. XEN 67.7 ± 9.0 years; p = 0.002). Postoperative complications were comparable between the two groups.

Conclusion Both MicroShunt and XEN are effective in significantly reducing IOP and glaucoma medications in OAG, and with a good safety profile.
Outcomes of CT-Guided Deeper Localization Technique for Superficial Pulmonary Nodules
Authors: Wu Jingpeng , Tian Ye , An Jianli , Zou Zibo , Dong Yanchao , Chen Zhuo , Niu Hongtao
Published: September 2023

Background The possibility of coil dislocation in computed tomography (CT)-guided microcoil localization of superficial pulmonary nodules is relatively high. The aim of the study is to investigate the outcomes of deeper localization technique during CT-guided microcoil localization of superficial pulmonary nodules before video-assisted thoracoscopic surgery (VATS).

Methods Fifty-seven identified superficial pulmonary nodules (nodule–pleural distance ≤ 1 cm on CT image) from 51 consecutive patients underwent CT-guided microcoil localization, and subsequent VATSs were included. The rate of technical success, complications, and excised lung volume were compared between deeper localization technique group and conventional localization technique group.

Results The technical success rate of the localization procedure was 100% (25/25) in the deeper localization group and 81.3% (26/32) in the conventional localization group (p = 0.030). Excluding one case of lobectomy, the excised lung volume in the deeper localization group and the conventional localization group was 39.3 ± 23.5 and 37.2 ± 16.2 cm3, respectively (p = 0.684). The incidence of pneumothorax was similar between the deeper localization group and the conventional localization group (24.0 vs. 21.9%, respectively, p = 0.850). The incidence of intrapulmonary hemorrhage in the deeper localization group was higher (16.0%) than that in the conventional localization group (6.3%), but the difference was not statistically significant (p = 0.388).

Conclusion CT-guided microcoil localization of superficial pulmonary nodules prior to VATS using a deeper localization technique is feasible. Deeper localization technique reduced the occurrence of dislocation but did not increase excised lung volume.
Treatment of walled-off necrosis using lumen-apposing metal stents versus plastic stents: a systematic review and meta-analysis of data from randomized trials
Authors: Bang Ji Young , Wilcox Charles Melbern , Navaneethan Udayakumar , Hawes Robert Holbrook , Varadarajulu Shyam
Published: September 2023

Background Walled-off necrosis (WON) is highly morbid disease most effectively managed by endoscopic drainage with lumen-apposing metal stents (LAMSs) or plastic stents, with or without necrosectomy. This meta-analysis compared the clinical outcomes of patients included in randomized trials treated using LAMSs or plastic stents.

Methods The MEDLINE and EMBASE databases were searched to identify all data collected from randomized trials comparing LAMSs and plastic stents for the treatment of WON. The primary outcome measure was need for endoscopic necrosectomy.

Results Three studies comprising 206 patients met inclusion criteria. Except for procedure duration, which was significantly shorter for LAMSs (standardized mean difference [SMD] −1.22, 95%CI −1.64 to −0.79), there was no significant difference in need for necrosectomy (38.5% vs. 41.2%; risk ratio [RR] 1.07, 95%CI 0.79–1.45), number of interventions (SMD −0.09, 95%CI −0.40 to 0.22), treatment success (90.7% vs. 94.5%; RR 0.96, 95%CI 0.87–1.06), recurrence (4.6% vs. 0.6%; RR 3.73, 95%CI 0.42–33.0), readmission (42.6% vs. 50.2%; RR 0.84, 95%CI 0.62–1.14), length of hospitalization (SMD −0.06, 95%CI −0.55 to 0.43), mortality (8.5% vs. 9.8%; RR 0.70, 95%CI 0.30–1.66), new-onset organ failure (10.6% vs. 14.6%; RR 0.72, 95%CI 0.16–3.32), bleeding (11.0% vs. 10.7%; RR 1.09, 95%CI 0.34–3.44), procedural adverse events (23.6% vs. 19.2%; RR 1.38, 95%CI 0.82–2.33), or overall costs (SMD −0.04, 95%CI −0.31 to 0.24) between LAMSs and plastic stents, respectively.

Conclusions Except for procedure duration, there is no significant difference in clinical outcomes for patients with WON treated using LAMSs or plastic stents.
Recent Advances in Electrochemically Mediated Reactions of Diselenides
Authors: Mo Zu-Yu , Pan Ying-Ming , Zhan Lei , Wang Qian , Tang Hai-Tao
Published: September 2023

Organoselenium compounds are crucial molecules that are utilized extensively in diverse fields such as medicine, agriculture, catalysis, and organic materials. The incorporation of selenium atoms into organic molecules holds significant importance in synthetic chemistry. Organic electrochemical synthesis, a green, mild, and efficient strategy, has displayed remarkable potential for organoselenium chemistry synthesis. Consequently, there has been substantial interest in recent years in researching electrochemically mediated synthesis of organoselenium compounds. This review provides an overview of the progress made in electrochemically mediated organic selenium reactions over the last decade, including electrochemical mediated selenium catalysis, electrochemical oxidation of diselenide coupling, and electrochemical oxidation tandem selenocyclization. The scope, limitations, and mechanisms of those reactions are emphasized.

1 Introduction

2 Electrochemical Selenium-Catalyzed Reactions

3 Electrochemically Mediated Coupling of Aromatic/Heterocyclic Rings with Diselenides

4 Electrochemically Mediated Tandem Selenocyclization

5 Conclusion
Bis(pinacoloto)diboron/4-Phenylpyridine System for One-Pot Photocatalyzed Borylation and Reduction of Aldehyde: Synthesis of Tavaborole in a Flow Reactor
Authors: Kumar Kankanala Naveen , Mhate Mouzma , Swain Sharada Prasanna , Ravichandiran Velayutham
Published: September 2023

A photocatalyzed one-pot borylation of haloarene and reduction of aldehyde by cocatalysis of bis(pinacoloto)diboron/4-phenylpyridine is reported. The reaction was carried out in a flow reactor by irradiating the reaction at 410 nm, with residence time of 10 minutes. The method was successfully applied for the synthesis of tavaborole in a single step with 81% yield.
Radiation Safety and External Radiation Exposure Rate of Patients Receiving I-131 Therapy for Hyperthyroidism and Remnant Ablation as Outpatient: An Institutional Experience
Authors: Bhatia Nisha , Dhingra Vandana K. , Mittal Pulkit , Saini Sunil
Published: September 2023

Objective Our objective was to study the radiation exposure rate as function of time in the administration of radioiodine iodine-131 (I-131) for the treatment of thyrotoxicosis or Graves' disease and remnant ablation on an outpatient basis at the Department of Nuclear Medicine, and also, to study the impact of revised discharge criteria for radioiodine therapy enforced by the Atomic Energy Regulatory Board (AERB) of India.

Materials and Methods This study included patients who underwent low-dose radioiodine therapy using I-131. Patients were classified into two different groups, that is, group A and group B. Group A included patients receiving low dose I-131 for the treatment of thyrotoxicosis, whereas group B included patients receiving I-131 therapy for the ablation of residual thyroid tissue after total thyroidectomy. The radiation exposure rate was measured using a radiation detector in milli roentgen per hour (mR/h) at 5 cm distance of stomach and neck levels and with the patient standing at the distance of 1 m after oral administration of I-131 at 0, 1, and 2 hours.

Results A total of 134 (17 males and 117 females) patients were included in the study. Group A comprised 102 (14 male and 88 females) patients and group B of 32 (3 males and 29 females) patients. At the neck level, the average exposure rate in group A versus group B after 0, 1, and 2 hours was observed to be 6.9 versus 22.27 mR/h, 33.67 versus 43.39 mR/h, and 41.75 versus 48.90 mR/h, respectively. At the stomach level, the exposure rate was 23.65 versus 71.32 mR/h, 13.27 versus 48.45 mR/h, and 9.91 versus 39.43 mR/h after 0, 1, and 2 hours, respectively. At a distance of 1 m, the exposure rate was 1.31 versus 2.99 mR/h, 1.05 versus 2.58 mR/h, and 0.92 versus 2.21 mR/h, respectively.

Conclusion Exposure rate measured for patients treated with up to 1,110 MBq (30 mCi) of I-131 was under permissible limits as per revised discharged limits, that is, 50 µSv/h (5 mR/h) prescribed by AERB, India. The patients undergoing radioiodine therapy I-131 (up to 1,110 MBq/30 mCi) can be discharged safely 2 hours postadministration following good work practice along with providing proper radiation safety instructions to patients.
Buchholzia coriacea Leaves Attenuated Dyslipidemia and Oxidative Stress in Hyperlipidemic Rats and Its Potential Targets In Silico
Authors: Uti Daniel E. , Ibiam Udu A. , Omang Wilson A. , Udeozor Precious A. , Umoru Grace U. , Nwadum Solomon K. , Bawa Inalegwu , Alum Esther U. , Mordi Joseph C. , Okoro Edith O. , Obeten Uket Nta , Onwe Eucharia N. , Zakari Suleiman , Opotu Ohunene Rukayat , Aja Patrick M.
Published: September 2023

The study aimed to investigate how the solvent extract of Buchholzia coriacea (BCE), a widely known hypolipidemic agent, could contribute to hyperlipidemia treatment and identify the potential bioactive compounds. We studied Wistar albino rats, dividing them into seven groups: the normal control, normal rats treated with 400 mg/kg.b.wt of BCE (NRG group), the hyperlipidemic control (HPC group), hyperlipidemic rats treated with atorvastatin, a standard control drug (SC group), as well as 200, 400, and 800 mg/kg.b.wt of BCE extract respectively (T1, T2, T3 groups). The potential compounds that functioned in BCE extract were analyzed by in silico binding to acetyl-CoA carboxylase (ACC) and fatty acid synthase (FASN). The binding affinities and drug-like properties of the compounds were determined using virtual screening and absorption distribution metabolism excretion and toxicity prediction analysis. The gas chromatography-mass spectrometry analysis identified alkaloids, saponins, flavonoids, phenols, terpenoids, and 44 chemical compounds in the leaf extract of BCE. BCE significantly reduced the levels of triacylglycerol, total cholesterol, low-density lipoprotein, very low-density lipoprotein, atherogenic coefficient, atherogenic index, and coronary risk index, while enhancing the levels of high-density lipoprotein and cardioprotective index in comparison to the HPC group. The BCE reduced malondialdehyde quantities, which exhibit high levels in HPC. Superoxide dismutase and glutathione peroxidase activities as well as glutathione levels, which are otherwise reduced in HPC, were increased upon the BCE treatment. Among the identified BCE compounds, lupenone and 2,7-dimethylnaphthalene exhibited the highest binding affinities to ACC and FASN, suggesting that these two compounds might be the bioactive BCE components displaying hypolipidemic properties. BCE is found to be beneficial in blocking hyperlipidemia through the modulation of lipid profile, the protection of cardiovascular function, as well as the suppression of oxidative stress. BCE may be a natural source for exploring novel drugs for the treatment of dyslipidemia.
Highly efficient jellyfish jet propulsion
Authors: Shapiro Maura
Published: September 2023

Finding the ideal open-close frequency for efficient jet propulsion in jellyfish motion.
Magnetron sputtering system for depositing boron carbide film use as neutron detection
Authors: Zhu Jingtao , Liu Yang , Zhu Hangyu , Zhou Jianrong , Zhou Xiaojuan , Zhu Jie , Zhu Lin , Sun Zhijia , Chen Yuanbo , Cui Mingqi , Zhu Yunping , Jin Changli
Published: September 2023

Boron carbide (B4C) films used as neutron conversion layers were investigated in this paper to replace the traditional 3He detectors due to their shortage. A magnetron sputtering system was developed for depositing large-size B4C films with the 1500 × 400 mm2 uniform-area. B4C films at the micron scale were deposited on aluminum (Al), float glass (SiO2), and silicon (Si) substrates with an inserting adhesion layer. The key characteristics, including surface morphology, thickness nonuniformity, purity, and neutron efficiency of B4C films, were characterized using atomic force microscopy, scanning electron microscopy, grazing incidence x-ray reflectivity, x-ray photoelectron spectroscopy, and neutron radiation metrology. The experimental results indicate that the deposition thickness nonuniformity across a 1500 × 400 mm2 area was better than ±3%. The stoichiometric ratio of boron atoms and carbon atoms (B/C) is 5.18, with 6 at. % O and 0.79 at. % N concentrations. The measured neutron detection efficiency of a 3 µm 10B4C film for 25 meV neutrons was 3.3 ± 0.3(sys)%, which is close to the simulated results (3.4%). The results show that the B4C neutron conversion layer is a promising substitute for 3He for neutron detection in the future.
Can a deep-learning model make fast predictions of vacancy formation in diverse materials?
Authors: Choudhary Kamal , Sumpter Bobby G.
Published: September 2023

The presence of point defects, such as vacancies, plays an important role in materials design. Here, we explore the extrapolative power of a graph neural network (GNN) to predict vacancy formation energies. We show that a model trained only on perfect materials can also be used to predict vacancy formation energies (Evac) of defect structures without the need for additional training data. Such GNN-based predictions are considerably faster than density functional theory (DFT) calculations and show potential as a quick pre-screening tool for defect systems. To test this strategy, we developed a DFT dataset of 530 Evac consisting of 3D elemental solids, alloys, oxides, semiconductors, and 2D monolayer materials. We analyzed and discussed the applicability of such direct and fast predictions. We applied the model to predict 192 494 Evac for 55 723 materials in the JARVIS-DFT database. Our work demonstrates how a GNN-model performs on unseen data.
Dynamic control of light scattering in a single particle enabled by time modulation
Authors: Sadafi Mohammad Mojtaba , da Mota Achiles Fontana , Mosallaei Hossein
Published: September 2023

The interaction of light with time-varying materials offers intriguing opportunities for controlling light scattering and wavefront manipulation, thereby unlocking fascinating applications in the realm of optics and photonics. In this study, we present an analytical solution for the scattering from a particle made of a material with time-varying permittivity by exploiting the T-matrix approach. Through the manipulation of the active medium's eigenvalues, we demonstrate the pivotal ability to regulate the elements of a dynamically controlled T-matrix, thus enabling precise control over the scattering characteristics of the particle. Crucially, this dynamic control is achieved without resorting to modifying the particle's inherent physical parameters, such as shape, size, and dispersion. We demonstrate that the eigenvalues of the dynamic material can be skillfully manipulated through the adequate choice of the particle's modulation function, resulting in either in-phase or out-of-phase interactions between the magnetic and electric dipole modes, allowing us to satisfy the Kerker conditions at diverse harmonics. The results of the optimal modulation functions are presented in both the near-field and far-field regions, revealing time modulation as a dynamic means of achieving unidirectional scattering. Our findings pave the way for developing time-varying structures comprising dynamic meta-atoms, offering valuable insight into advanced light–matter interactions, and providing lucrative guidance for future research in the realm of dynamic photonic systems.
Electron inertia effects in 3D hybrid-kinetic collisionless plasma turbulence
Authors: Muñoz Patricio A. , Jain Neeraj , Farzalipour Tabriz Meisam , Rampp Markus , Büchner Jörg
Published: September 2023

The effects of the electron inertia on the current sheets that are formed out of kinetic turbulence are relevant to understand the importance of coherent structures in turbulence and the nature of turbulence at the dissipation scales. We investigate this problem by carrying out 3D hybrid-kinetic Particle-in-Cell simulations of decaying kinetic turbulence with our CHIEF code. The main distinguishing feature of this code is an implementation of the electron inertia without approximations. Our simulation results show that the electron inertia plays an important role in regulating and limiting the largest values of current density in both real and wavenumber Fourier space, in particular, near and, unexpectedly, even above electron scales. In addition, the electric field associated with the electron inertia dominates most of the strongest current sheets. The electron inertia is thus important to accurately describe the properties of current sheets formed in turbulence at electron scales.
Influence of ambient pressure and laser energy on the plasma dynamics and parameters of laser-irradiated polyvinyl chloride
Authors: Xu Yongfeng , Yang Liang , Zhou Dongjian , Li Qingwei , Shi Wenbo , Jin Yuqi
Published: September 2023

The dependence of propulsion performance generated by laser ablation of polyvinyl chloride on laser energy and pressure is investigated using Q-switched Nd: YAG laser with the wavelength of 1064 nm. When the pressure is decreased, the impulse and coupling coefficient rise first and then decline. Such a trend is also reflected in the variation of coupling coefficient with laser energy in the whole pressure range. However, the change in impulse with laser energy at atmospheric pressure is not completely consistent with that at low pressure levels. The dynamic behavior and duration of plasma plume are considered to be the factors for the difference in propulsion performance. By capturing the fast exposure images of plume, the separation at atmospheric pressure and severe expansion accompanied by rapid quenching in near vacuum are observed. Moreover, the plasma plume lasts longer time at high pressures. It is ascribed to the higher electron temperature, which promotes background gas to excite and ionize. Since the electron density increases with the improvement of laser energy and pressure, the absorption of electrons to laser energy becomes stronger through the inverse bremsstrahlung mechanism. Accordingly, the shielding effect of plasma is enhanced, causing the weak laser-target interaction. The result is that the crater depth and ablative mass increase with decreasing pressure. This work is important for understanding the energy conversion mechanism and optimizing the laser propulsion performance.
Magnetoelectrics enables large power delivery to mm-sized wireless bioelectronics
Authors: Kim Wonjune , Tuppen C. Anne , Alrashdan Fatima , Singer Amanda , Weirnick Rachel , Robinson Jacob T.
Published: September 2023

To maximize the capabilities of minimally invasive implantable bioelectronic devices, we must deliver large amounts of power to small implants; however, as devices are made smaller, it becomes more difficult to transfer large amounts of power without a wired connection. Indeed, recent work has explored creative wireless power transfer (WPT) approaches to maximize power density [the amount of power transferred divided by receiver footprint area (length × width)]. Here, we analyzed a model for WPT using magnetoelectric (ME) materials that convert an alternating magnetic field into an alternating voltage. With this model, we identify the parameters that impact WPT efficiency and optimize the power density. We find that improvements in adhesion between the laminated ME layers, clamping, and selection of material thicknesses lead to a power density of 3.1 mW/mm2, which is over four times larger than previously reported for mm-sized wireless bioelectronic implants at a depth of 1 cm or more in tissue. This improved power density allows us to deliver 31 and 56 mW to 10 and 27-mm2 ME receivers, respectively. This total power delivery is over five times larger than similarly sized bioelectronic devices powered by radiofrequency electromagnetic waves, inductive coupling, ultrasound, light, capacitive coupling, or previously reported magnetoelectrics. This increased power density opens the door to more power-intensive bioelectronic applications that have previously been inaccessible using mm-sized battery-free devices.
Multi-hole coupling power monitor with tapered sub-waveguide for dual-frequency high-power gyrotron
Authors: Yanai R. , Takeuchi T. , Mizuno Y. , Yoshimura Y. , Nishiura M. , Igami H. , Takahashi H. , Tsujimura T. Ii , Kenmochi N.
Published: September 2023

In magnetically confined fusion plasmas, a gyrotron is an essential auxiliary heating device for generating and sustaining plasma through electron cyclotron resonance heating owing to its ability to generate high-power microwaves. Microwaves emitted from a gyrotron are often transmitted through waveguides, and the transmitted power is monitored by a power monitor with a multi-hole directional coupler at the miter bend of the transmission line. Recently, a high-power dual-frequency gyrotron has been installed and operated in the Large Helical Device. A power monitor with good sensitivity to multiple frequencies is required to monitor the power transmission of the different frequencies at the same transmission line. In order to realize the power monitor, which can couple with the multiple-frequency microwaves, we focused on a sub-waveguide shape in the power monitor and investigated the influence of the tapered sub-waveguide by conducting electromagnetic simulations using a simple model. We also performed the high-power test using a power monitor with a tapered sub-waveguide. The experimental result was different from the simulation, but enough receiving power was obtained at both 116 and 154 GHz.
Insight into the evolution of electrical properties for Schottky-barrier IGZO thin-film transistors with Cu-based Schottky contacts
Authors: Li Yuzhi , Zhou Yue , Zou Shenghan , Lan Linfeng , Gong Zheng
Published: September 2023

In this work, we performed systematic electrical characterization and analysis of indium–gallium–zinc oxide (IGZO) Schottky-barrier thin-film transistors (SBTFTs) with different Cu-based Schottky contact structures. It was found that the Schottky barrier height (ΦB) between the IGZO layer and the Cu electrode could be modulated notably by changing the thickness of the AlOx tunnel layer, and the variation in ΦB significantly changed the saturation drain current (Idsat) of the IGZO SBTFTs based on the Schottky contacts but only had a minor influence on the saturation voltage (Vdsat) of the devices. Furthermore, Cu/Al stacked source/drain electrodes and silicon nitride (SiNx) passivation were employed to tailor the contact resistance and channel resistance of the IGZO SBTFTs, which led to an increase in Idsat and a variation in Vdsat. A universal resistance–capacitance network model was proposed to explain the observed evolution of Vdsat of the SBTFTs with different device structures. This work provides meaningful insight into developing low-cost metal oxide SBTFTs with tailored device performances.
Reconstruction, forecasting, and stability of chaotic dynamics from partial data
Authors: Özalp Elise , Margazoglou Georgios , Magri Luca
Published: September 2023

The forecasting and computation of the stability of chaotic systems from partial observations are tasks for which traditional equation-based methods may not be suitable. In this computational paper, we propose data-driven methods to (i) infer the dynamics of unobserved (hidden) chaotic variables (full-state reconstruction); (ii) time forecast the evolution of the full state; and (iii) infer the stability properties of the full state. The tasks are performed with long short-term memory (LSTM) networks, which are trained with observations (data) limited to only part of the state: (i) the low-to-high resolution LSTM (LH-LSTM), which takes partial observations as training input, and requires access to the full system state when computing the loss; and (ii) the physics-informed LSTM (PI-LSTM), which is designed to combine partial observations with the integral formulation of the dynamical system’s evolution equations. First, we derive the Jacobian of the LSTMs. Second, we analyze a chaotic partial differential equation, the Kuramoto–Sivashinsky, and the Lorenz-96 system. We show that the proposed networks can forecast the hidden variables, both time-accurately and statistically. The Lyapunov exponents and covariant Lyapunov vectors, which characterize the stability of the chaotic attractors, are correctly inferred from partial observations. Third, the PI-LSTM outperforms the LH-LSTM by successfully reconstructing the hidden chaotic dynamics when the input dimension is smaller or similar to the Kaplan–Yorke dimension of the attractor. The performance is also analyzed against noisy data. This work opens new opportunities for reconstructing the full state, inferring hidden variables, and computing the stability of chaotic systems from partial data.
Non-Oberbeck–Boussinesq effects in two-dimensional Rayleigh–Bénard convection of different fluids
Authors: Pan Xiaomin , Choi Jung-Il
Published: September 2023

Non-Oberbeck–Boussinesq (NOB) effects in three representative fluids are quantitatively investigated in two-dimensional Rayleigh–Bénard convection. Numerical simulations are conducted in air, water, and glycerol with Prandtl numbers of Pr=0.71,4.4, and 2547, respectively. We consider Rayleigh number Ra∈[106,109] involving temperature difference (Δθ̃) of up to 60 K. The velocity and temperature profiles are found to be top-bottom antisymmetric under NOB conditions. As Pr increases, the time-averaged temperature of the cavity center ⟨θc⟩t increases under NOB conditions and the value of ⟨θc⟩t is only weakly influenced by Ra for all fluids. For Pr = 4.4 and 2547, with the enhancement of NOB effects, ⟨θc⟩t linearly increases and the maximum θ rms decreases/increases, and its location shifts toward/away from the wall near the bottom/top wall. Dispersed ⟨θc⟩t points and opposite phenomenon are observed in Pr = 0.71. The Nusselt number (Nu) and thermal boundary layer thickness at hot and cold walls (λ¯h,cθ) of the three fluids are comparable, and the Reynolds number (Re) significantly decreases as Pr increases. Under the NOB conditions with Pr = 4.4 and 2547, Nu decreases, Re increases, and λ¯hθ (λ¯cθ) thins (thickens) in an approximately linear fashion. Furthermore, the NOB effects on Nu, Re, and λ¯h,cθ are relatively small for Pr = 0.71 and 4.4, whereas the modifications caused by NOB effects at Pr = 2547 are more significant. The power-law scaling factors of Nu, Re, and λ¯h,cθ are demonstrated to be robust to Pr, as well as NOB effects.
Silicon diffusion in AlN
Authors: Bonito Oliva V. , Mangelinck D. , Hagedorn S. , Bracht H. , Irmscher K. , Hartmann C. , Vennéguès P. , Albrecht M.
Published: September 2023

In this study, we investigate the diffusion of Si donors in AlN. Amorphous Si1−xNx sputtered on the surface of bulk AlN with low dislocation density is used as a Si source. The diffusion experiments are conducted through isochronal and isothermal annealing in a protective N2 atmosphere at temperatures between 1500 and 1700 °C. The Si depth profiles measured by secondary ion mass spectrometry exhibit a convex box-like shape with a steep diffusion front. These concentration profiles are best described with a diffusion coefficient that depends on the square of local Si concentration. From the characteristic box-shaped Si profiles, we conclude that diffusion of Si in AlN is mediated by singly negatively charged dopant–vacancy pairs SiAlVAl−. The strong concentration dependence of Si diffusion is due to the electric field associated with the incorporation of Si donors (SiAl+1) on substitutional Al lattice sites and reflects that Si is fully electrically active at diffusion temperature. The experimentally obtained extrinsic Si diffusion coefficient is reduced to intrinsic doping conditions. The temperature dependence of Si diffusion for intrinsic conditions is described by an activation enthalpy of (10.34±0.32)eV and a pre-exponential factor of 235−203+1485cm2s−1. The migration enthalpy of the donor–vacancy pair SiAlVAl− is estimated to be around 3.5 eV. This estimation is based on the activation enthalpy of the transport capacity of SiAlVAl− and theoretical results concerning the formation energy of negatively charged vacancies on Al-sites in AlN.
Field-free room-temperature modulation of magnetic bubble and stripe domains in 2D van der Waals ferromagnetic Fe3GaTe2
Authors: Zhang Gaojie , Yu Jie , Wu Hao , Yang Li , Jin Wen , Zhang Wenfeng , Chang Haixin
Published: September 2023

Field-free room-temperature modulating magnetic domain structures and realizing stable nanoscale magnetic bubbles in 2D van der Waals (vdW) intrinsic ferromagnets are fundamentally important for 2D spintronic devices. However, it is still very challenging for the absence of a proper room-temperature 2D vdW ferromagnet with suitable perpendicular magnetic anisotropy. Here, by using a 2D vdW intrinsic room-temperature ferromagnetic Fe3GaTe2 crystal with Curie temperature of over ∼340 K and large perpendicular magnetic anisotropy, we study field-free thickness-dependent magnetic domain structure evolution in Au-capped 2D Fe3GaTe2 nanosheets by magnetic force microscopy at room temperature. The magnetic domain varies from a labyrinth-like stripe domain to a single domain in Au/Fe3GaTe2 (20/x nm) with decreasing Fe3GaTe2 thickness from 129 to 17.8 nm. Importantly, the field-free, spontaneous, stable, nanoscale magnetic bubbles can be realized in Au/Fe3GaTe2 (8/x nm) with a wide range of Fe3GaTe2 thickness over 30 nm. The highest bubble density and smallest diameter are measured as ∼2.65 μm−1 and ∼130 nm, respectively, superior to that of most room-temperature magnetic bubble materials. This work paves the way for field-free, room-temperature magnetic domain modulation and vdW-integrated spintronic applications of 2D vdW crystals.
Ultraviolet/visible distinguishable self-powered photodetector enhanced by pyro-phototronic effect in p–n–p junction
Authors: Zhang Yongle , Xue Hanyi , Zhu Meng , Wang Zhaona
Published: September 2023

Self-powered photodetectors (PDs) with distinguishable wavelength detection have great application potential in intelligent optoelectronics. However, slow response speed, low responsivity, and signal interference prevent its development and applications. Here, an asymmetric bipolar p-NiO/n-ZnO/p-Si heterojunction is designed as a wavelength-distinguishable PD by using two tandem p–n junctions to reduce the wavelength interference and effectively separate photo-generated carriers. Bidirectional transient photocurrents are achieved in the external circuit for ultraviolet and visible detection by smartly using the pyro-phototronic effect induced by the variations of spontaneous polarization and interface-induced polarization within the p–n–p junction. The transient peak-to-peak current are thus significantly improved by 2310% for 325 nm lasing and by 5950% for 442 nm lasing. This approach can be used to realize wavelength-distinguishable detection through flexibly selecting materials and using the pyro-phototronic effect. The designed PD might have potential applications in the fields of environmental detection, smart imaging, and intelligent optoelectronics.
Molecular dynamics simulations of electrochemical interfaces
Authors: Zeng Liang , Peng Jiaxing , Zhang Jinkai , Tan Xi , Ji Xiangyu , Li Shiqi , Feng Guang
Published: September 2023

Molecular dynamics (MD) simulations have become a powerful tool for investigating electrical double layers (EDLs), which play a crucial role in various electrochemical devices. In this Review, we provide a comprehensive overview of the techniques used in MD simulations for EDL studies, with a particular focus on methods for describing electrode polarization, and examine the principle behind these methods and their varying applicability. The applications of these approaches in supercapacitors, capacitive deionization, batteries, and electric double-layer transistors are explored, highlighting recent advancements and insights in each field. Finally, we emphasize the challenges and potential directions for future developments in MD simulations of EDLs, such as considering movable electrodes, improving electrode property representation, incorporating chemical reactions, and enhancing computational efficiency to deepen our understanding of complex electrochemical processes and contribute to the progress in the field involving EDLs.
Efficient global sensitivity analysis of kinetic Monte Carlo simulations using Cramérs–von Mises distance
Authors: Dortaj Sina , Matera Sebastian
Published: September 2023

Typically, the parameters entering a physical simulation model carry some kind of uncertainty, e.g., due to the intrinsic approximations in a higher fidelity theory from which they have been obtained. Global sensitivity analysis (GSA) targets quantifying which parameter uncertainties impact the accuracy of the simulation results, e.g., to identify which parameters need to be determined more accurately. We present a GSA approach based on the Cramérs–von Mises distance. Unlike prevalent approaches, it combines the following properties: (i) it is equally suited for deterministic as well as stochastic model outputs, (ii) it does not require gradients, and (iii) it can be estimated from numerical quadrature without further numerical approximations. Using quasi-Monte Carlo for numerical integration and a first-principles kinetic Monte Carlo model for the CO oxidation on RuO2(110), we examine the performance of the approach. We find that the results agree very well with what is known in the literature about the sensitivity of this model and that the approach converges in a modest number of quadrature points. Furthermore, it appears to be robust against even extreme relative noise. All these properties make the method particularly suited for expensive (kinetic) Monte Carlo models because we can reduce the number of simulations as well as the target variance of each of these.
Hydrodynamic performance of a self-protected hybrid offshore wind-wave energy system
Authors: Cong Peiwen , Liu Yingyi , Wei Xuanqi , Ning Dezhi , Teng Bin
Published: September 2023

The load-bearing capacity is a pivotal consideration in the design of offshore renewable energy structures. This paper aims to address the technical challenges associated with the additional wave loads caused by the integrated devices in a hybrid system for the multi-purpose utilization of coastal renewable energy. A self-protected hybrid wind-wave energy system is proposed, in which an oscillating water column (OWC) device is attached at a monopile foundation of an offshore wind turbine. In the meantime, the OWC is connected by a submerged horizontal perforated plate at its exterior shell, which is expected to minimize the wave loads on the system. The hydrodynamic performance of the system is investigated. A novel approach is developed to model the wave interaction with the hybrid system. This efficient approach removes the necessity of decomposing the wave-scattering field into diffraction and pressure-dependent radiation components. Detailed numerical computation is then conducted for both regular and irregular sea states. Various hydrodynamic properties related to the system, such as wave energy harvesting, wave force/moment, and free-surface elevation, have been evaluated. Numerical results manifest the feasibility of imposing a negligible effect on the high wave energy harvesting while reducing the high wave loads by manipulating the submerged horizontal perforated plate. The impact of the perforated plate on the dominant wave energy harvesting in the long-period region is found to be trivial. In contrast, it can affect the high bending moment in the short-period region, which causes a reduction of greater than 15%.
On the longitudinal wave pumping in fluid-filled compliant tubes
Authors: Aghilinejad Arian , Rogers Bryson , Geng Haojie , Pahlevan Niema M.
Published: September 2023

This study investigates the physics of the longitudinal stretching-based wave pumping mechanism, a novel extension of the traditional impedance pump. In its simplest form, an impedance pump consists of a fluid-filled elastic tube connected to rigid tubes with a wave generator. These valveless pumps operate based on the principles of wave propagation in a fluid-filled compliant tube. Cardiovascular magnetic resonance imaging of the human circulatory system has shown substantial stretching of the aorta (the largest compliant artery of the body carrying blood) during the heart contraction and recoil of the aorta during the relaxation. Inspired by this dynamic mechanism, a comprehensive analysis of a longitudinal impedance pump is conducted in this study where waves are generated by stretching of the elastic wall and its recoil. We developed a fully coupled fluid–structure interaction computational model consisting of a straight fluid-filled elastic tube with longitudinal stretch at one end and a fixed reflection site at the other end. The pump's behavior is quantified as a function of stretching frequency and tube wall characteristics. Our results indicate that stretch-related wave propagation and reflection can induce frequency-dependent pumping. Findings suggest a non-linear pattern for the mean flow–frequency relationship. Based on the analysis of the propagated waveforms, the underlying physical mechanism in the longitudinal impedance pump is discussed. It is shown that both the direction and magnitude of the net flow strongly depend on the wave characteristics. These findings provide a fundamental understanding of stretch-related wave pumping and can inform the future design of such pumps.
Shock-induced melting and crystallization in titanium irradiated by ultrashort laser pulse
Authors: Zhakhovsky Vasily , Kolobov Yury , Ashitkov Sergey , Inogamov Nail , Nelasov Ivan , Manokhin Sergey , Khokhlov Victor , Ilnitsky Denis , Petrov Yury , Ovchinnikov Andrey , Chefonov Oleg , Sitnikov Dmitry
Published: September 2023

Modification of titanium microstructure after propagation of a melting shock wave (SW) generated by a femtosecond laser pulse is investigated experimentally and analyzed using hydrodynamic and atomistic simulations. Scanning and transmission electron microscopy with analysis of microdiffraction is used to determine the microstructure of modified subsurface layers of titanium. We found that two layers are modified beneath the surface. A top surface polycrystalline layer of nanoscale grains is formed from shock-molten material via rapid crystallization. In a deeper subsurface layer, where the shock-induced melting changes into plastic deformation due to attenuation of SW, the grain structure of solid is considerably affected, which results in a grain size distribution differing from that in the intact titanium. Molecular dynamics simulation of single-crystal titanium reveals that the SW front continues to melt even after its temperature drops below the melting curve Tm(P). The enormous shear stress of ∼12 GPa generated in a narrow SW front leads to free slip of atomic planes, collapse of the crystal lattice, and formation of a supercooled metastable melt. Such melt crystallizes in an unloading tail of SW. The mechanical melting ceases after drop in the shear stress giving rise to the shock-induced plastic deformation. The last process triggers a long-term rearrangement of atomic structures in solid. The overall depth of modified layers is limited by SW attenuation to the Hugoniot elastic limit and can reach several micrometers. The obtained results reveal the basic physical mechanisms of surface hardening of metals by ultrashort laser pulses.
Scale-free avalanches in arrays of FitzHugh–Nagumo oscillators
Authors: Contreras Max , Medeiros Everton S. , Zakharova Anna , Hövel Philipp , Franović Igor
Published: September 2023

The activity in the brain cortex remarkably shows a simultaneous presence of robust collective oscillations and neuronal avalanches, where intermittent bursts of pseudo-synchronous spiking are interspersed with long periods of quiescence. The mechanisms allowing for such coexistence are still a matter of an intensive debate. Here, we demonstrate that avalanche activity patterns can emerge in a rather simple model of an array of diffusively coupled neural oscillators with multiple timescale local dynamics in the vicinity of a canard transition. The avalanches coexist with the fully synchronous state where the units perform relaxation oscillations. We show that the mechanism behind the avalanches is based on an inhibitory effect of interactions, which may quench the spiking of units due to an interplay with the maximal canard. The avalanche activity bears certain heralds of criticality, including scale-invariant distributions of event sizes. Furthermore, the system shows increased sensitivity to perturbations, manifested as critical slowing down and reduced resilience.
Control on the density and optical properties of color centers at SiO2/SiC interfaces by oxidation and annealing
Authors: Nakanuma Takato , Tahara Kosuke , Kutsuki Katsuhiro , Shimura Takayoshi , Watanabe Heiji , Kobayashi Takuma
Published: September 2023

Color centers in solids can serve as single photon emitters (SPEs) those are important in many quantum applications. Silicon carbide (SiC) is a promising host for color centers because of its well-established crystal growth and device technologies. Although color centers with extremely high brightness were found at the silicon dioxide (SiO2)/SiC interface, controlling their density and optical properties remains a challenge. In this study, we demonstrate control over the color centers at the SiO2/SiC interface by designing the oxidation and annealing conditions. We report that post-oxidation CO2 annealing has the ability to reduce the color centers at the interface and form well-isolated SPEs with bright emission. We also discuss the correlation between the color centers and electrically active defects.
Shape effects of Darcy–Forchheimer unsteady three-dimensional CdTe-C/H2O hybrid nanofluid flow over a stretching sheet with convective heat transfer
Authors: Mohana C. M. , Rushi Kumar B.
Published: September 2023

The present investigation explores the Darcy–Forchheimer unsteady hybrid nanofluid flow over a bidirectionally stretching sheet, with particular emphasis on convective heat transfer. The main focus of this study is to investigate the heat transfer and flow characteristics of sphere, brick, and blade-shaped cadmium telluride and graphite nanoparticle suspensions in water with viscous dissipation and Joule heating effects. The methodology involves the conversion of governing partial differential equations into ordinary differential equations (ODEs) through similarity variables. An implicit Keller Box numerical technique is used to solve the resulting ODEs. Porosity and inertia coefficients reduce the velocity, but the reverse trend is observed for the temperature profiles. Eckert and Biot numbers enhance the temperature of the fluid. The variation in the nanoparticle volume fraction ranges from 2% to 10%. For 10% nanoparticle volume fraction, CdTe/H2O, C/H2O mono-nanofluids achieve 25.71% and 30.76% heat transfer rate, respectively. However, for 10% of the nanoparticle volume fraction, CdTe-C/H2O hybrid nanofluids achieve 28.6%, 34.66%, and 69.07%, and Al2O3-CuO/H2O hybrid nanofluids achieve 31.14%, 38.37%, and 83.21% heat transfer rates for spherical, brick, and blade-shaped nanoparticles. The heat transfer rate of Al2O3-CuO nanoparticles is found to be greater when compared to CdTe-C nanoparticles. In the context of CdTe-C/H2O and Al2O3-CuO/H2O hybrid nanofluids, it has been observed that blade-shaped nanoparticles exhibit heat transfer rates that are 25.55% and 32.41% higher than those achieved with brick-shaped nanoparticles, respectively. Blade-shaped nanoparticles exhibit a greater velocity and heat transport rate in comparison with spherical and brick-shaped nanoparticles.
Flashing ratchet effect for driving carriers to accelerate directional migration in organic photovoltaic devices
Authors: Li Han , Gao Teng , He Dongxin , Xie Shijie
Published: September 2023

The organic electron flashing ratchet experiment describes the phenomenon in which an electric current can be detected, even in the absence of a net potential bias. To understand the experimental mechanism at the quantum level, we utilize the quantum nonadiabatic method to simulate the electron dynamics in an organic polymer chain with the flashing ratchet potential. It is found that electrons exhibit directional migration with a velocity, which depends on both the asymmetry and the flashing frequency of the ratchet potential. In addition, the flashing ratchet, which describes the non-uniform and time-varying electric field, increases the velocity by 58.6% compared to the uniform electric field. The flashing ratchet effect exists intrinsically in actual organic photovoltaics (OPVs), due to the naturally uneven and time-varying inherent electric field caused by various inevitable factors in bulk heterojunctions (BHJ). Moreover, the ratchet potential can be artificially constructed by designing the morphology of the BHJ, which opens a promising avenue for driving electrons to accelerate directional migration, and improving the photoelectric conversion efficiency of OPVs.
Paint and Coating Physics
Authors: Tirumkudulu Mahesh S.
Published: September 2023

Paints and Coatings are ubiquitous with wide ranging applications in architectural and construction, aerospace, automotive, electronic, food, and the pharmaceutical industries. The manufacture and storage of paints, their application on a substrate, and the film formation process all involve fluid flow whose understanding and control is important for achieving the desired finish. Within this context, this special issue presents developments in advanced computational models, experiments, and analysis related to the various stages of paint formulation and their applications.