bluuebunny/crossref_metadata_2025 huggingface dataset:
Structure, function, and lipid sensing activity in the thioesterase superfamily
Authors: Little Molly , Ortlund Eric A.
Published: August 2024

Lipid synthesis and transport are essential for energy, production of cell membrane, and cell signaling. Acyl-CoA thioesterases (ACOTs) function to regulate intracellular levels of fatty acyl-CoAs through hydrolysis. Two members of this family, ACOT11 and ACOT12, contain steroidogenic acute regulatory related lipid transfer domains, which typically function as lipid transport or regulatory domains. This work reviews ACOT11 and ACOT12 structures and functions, and the potential role of the START domains in lipid transfer activity and the allosteric regulation of catalytic activity.
To target cellular senescence in diabetic kidney disease: the known and the unknown
Authors: Wei Yuehan , Mou Shan , Yang Qing , Liu Fang , Cooper Mark E. , Chai Zhonglin
Published: August 2024

Cellular senescence represents a condition of irreversible cell cycle arrest, characterized by heightened senescence-associated beta-galactosidase (SA-β-Gal) activity, senescence-associated secretory phenotype (SASP), and activation of the DNA damage response (DDR). Diabetic kidney disease (DKD) is a significant contributor to end-stage renal disease (ESRD) globally, with ongoing unmet needs in terms of current treatments. The role of senescence in the pathogenesis of DKD has attracted substantial attention with evidence of premature senescence in this condition. The process of cellular senescence in DKD appears to be associated with mitochondrial redox pathways, autophagy, and endoplasmic reticulum (ER) stress. Increasing accumulation of senescent cells in the diabetic kidney not only leads to an impaired capacity for repair of renal injury, but also the secretion of pro-inflammatory and profibrotic cytokines and growth factors causing inflammation and fibrosis. Current treatments for diabetes exhibit varying degrees of renoprotection, potentially via mitigation of senescence in the diabetic kidney. Targeting senescent cell clearance through pharmaceutical interventions could emerge as a promising strategy for preventing and treating DKD. In this paper, we review the current understanding of senescence in DKD and summarize the possible therapeutic interventions relevant to senescence in this field.
A Psycholinguistic Approach to the Management of Aphasia in a Case of Left Parietal Stroke
Authors: Yetter Audra W.
Published: August 2024

Purpose:

The purpose of this study was to illustrate the use of a psycholinguistic model of aphasia as a guide to inform clinical management in a case of left parietal stroke, in a typical hospital outpatient setting.

Method:

This study used a case report with retrospective chart review.

Results:

A 79-year-old man developed acute speaking difficulty and was diagnosed with a left ischemic parietal stroke. A psycholinguistic approach was applied to conceptualize the underlying nature of the aphasia as well as to navigate various treatment decisions. Based upon the resultant aphasia profile demonstrating broad phonological impairment of word production, phonomotor treatment was implemented.

Conclusion:

Incorporating psycholinguistic theories and practices into the clinical management of aphasia can provide clinicians with a relevant framework to guide clinical decision making through precise delineation of the nature of aphasia and selection of correspondingly targeted interventions.
Crypto Deep Ring Topology Firewall in Sensitive Data Transmission and Retrieval in Cloud
Authors: K. Soman Vikas , Natarajan V.
Published: August 2024

The data transmission and data retrieval process from the cloud is a critical issue because of cyber‐attacks. The data in the cloud is highly vulnerable and may fall prey to hackers. The hackers tend to attack the data in the public network, deteriorating the range of confidentiality and the authentication of the data. To prevent this attack on the cloud data, this manuscript proposes a crypto deep ring topology firewall to protect the cloud from data breaches. The data transmission has been performed using egress ring topology crypto encryption that solves the difficulty in isolating the traffic path between the edge and cloud network. Moreover, during the cloud data retrieval, the data interoperability issue arises due to the improper cloud service level agreement, which is solved using an application programing interface firewall fetch intrusion prevention system used in the secure transmission technique in which the data are entered into the transport and session layer of the firewall and then into the intrusion detection and prevention system thus sieving of data is carried out to solve the amenability violation of the cloud network and eliminate data interoperability issue. The proposed model was implemented in the Python platform and provided an enhanced level of encryption and decryption performance than the existing cloud retrieval model, producing high access speed to the cloud network with data security. The proposed work has proved to be highly robust against cyber attacks like man‐in‐the‐middle attacks and spoofing attacks.
Optimization strategy of UAV‐ARIS assisted vehicular communication system
Authors: Zhao Haitao , Xu Zhuoran , Ni Yiyang , Sun Wenxue , Zhu Hongbo , Liu Yaxuan , Mo Zhaoying
Published: August 2024

In recent years, the Integrated Satellite Aerial Terrestrial (I‐SAT) network has garnered significant attention as an innovative and integrated communication system. However, it still encounters interference in the face of the complex external environment. In this context, reconfigurable intelligent surface (RIS) provides a key way of solving this problem and effectively improves the performance and stability of the I‐SAT network. This article considers the combination of unmanned aerial vehicle (UAV) and RIS and proposes a novel architecture for sub‐connected active RIS (ARIS) under the energy consumption constraints of UAV and ARIS. The authors first provide a UAV‐ARIS based position prediction strategy for the vehicle. Then, a joint RIS phase shift, amplification and UAV trail optimization algorithm is proposed to pursue a high achievable rate. The interference between each link and the total energy consumption are all taken into consideration. In addition, a deep deterministic policy gradient (DDPG) algorithm is utilized for the optimization problem, and achieves convergence in continuous action space. Finally, the simulation results affirm the precision of the proposed method in significantly enhancing performance compared to other schemes.
Enhanced control of double integrating plus time delay systems using a two‐degree‐of‐freedom Smith predictor
Authors: Tavakoli Saeed
Published: August 2024

This article presents a novel control approach using a two‐degree‐of‐freedom (2‐DOF) Smith predictor structure for double integrating plus time delay plants. The PD and PID controllers, integral components of the Smith predictor scheme, serve distinct roles in the control process. The PD controller is responsible for set‐point tracking, while both PD and PID controllers contribute to the rejection of load disturbances. Each controller is designed using the pole placement technique, with an appropriate tuning parameter established to balance performance and robustness effectively. A low‐pass filter is incorporated to improve the response of the set‐point signal by attenuating high‐frequency noise. The proposed method's effectiveness is compared with Skogestad internal model control, a well‐known PID tuning method, to benchmark performance improvements and demonstrate the advantages of the 2‐DOF Smith predictor approach. Simulation and comparison analysis demonstrates that the proposed controller setting is suitable for industrial applications due to its quick set‐point tracking, effective load disturbance rejection, and smooth control signal. The study highlights the practical benefits of the 2‐DOF Smith predictor in enhancing industrial control system performance and suggests directions for future research, including experimental validation and robustness analysis under varying system parameters.
Dynamic optimisation of virtual synchronous generator to enhance stability of power system
Authors: Koiwa Kenta , Tomabechi Akira , Zanma Tadanao , Liu Kang‐Zhi
Published: August 2024

Virtual synchronous generators (VSGs) are essential for the high penetration of renewable energy sources. VSGs have virtual rotating inertia, a damping effect, and synchronising power such as actual SGs. Such features of VSGs offer a promising structure to improve the stability of power systems. VSGs are required to suppress power and system frequency oscillations. In addition, VSGs must operate within a current limit since they are vulnerable to the overcurrent, unlike actual SGs. The authors propose a novel dynamic and optimal VSG to enhance the frequency stability in power systems while guaranteeing the current limit. The proposed approach determines an optimal tuple of inertia and damping of VSG online and guarantees the current limit with the use of a circuit model. The effectiveness of the proposed method is demonstrated via experiments, comparing it with the conventional methods.
Gearbox fault diagnosis based on Gramian angular field and TLCA-MobileNetV3 with limited samples
Authors: Dou Shuihai , Cheng Xuemin , Du Yanping , Wang Zhaohua , Liu Yuxin
Published: August 2024

Gearbox fault diagnosis based on traditional deep learning often needs a large number of samples. However, the gearbox fault samples are limited in practical engineering, which could lead to poor diagnosis performance. Based on the above problems, this paper proposes a gearbox fault diagnosis method based on Gramian angular field (GAF) and TLCA-MobileNetV3 to achieve fast and accurate limited sample recognition under varying working conditions, and further achieve the cross-component fault diagnosis within the gearbox. First, the 1D signals are converted into 2D images through GAF. Second, a lightweight convolutional neural network is established. Coordinate attention (CA) is integrated into the network to establish remote dependency in space and improve the ability of feature extraction. The optimal strategy for model training is determined. Finally, a transfer learning strategy is designed. The lower structures of network are frozen. The higher structures of network are fine-tuned using limited samples. Through experimental verification, the proposed network could achieve limited sample fault diagnosis under varying working conditions and cross-component conditions.
Mechanical characteristics of dissimilar friction stir welding processes of aluminium alloy [AA 2024-T351 and AA 7075-T651]
Authors: Gebreamlak Getachew , Palani Sivaprakasam , Sirahbizu Belete
Published: August 2024

Aerospace industries have remained dependent on aluminium alloys for airframe structural components manufacturing due to their superior strength, fracture toughness, and ability to resist corrosion. Especially, AA2024 and AA7075 have been the most prominent and timely tested robust aluminium alloys in these manufacturing sectors. However, joining these aluminium alloys through conventional fusion welding is difficult. The present investigation focused on the mechanical and metallurgical properties of these high-strength dissimilar aluminium alloys 2024-T351 and 7075-T651 using a Friction Stir Welding (FSW) process. The effects of factors such as rotational speed RS (800–1200 rpm), welding speed WS (20–60 mm/min), and tool plunge depth (0.2–0.4 mm) on the ultimate tensile strength (UTS) and yield strength (YS) have been evaluated. The experimental procedure employed is based on RSM. The fractured surface morphology was investigated using SEM. The investigation result showed higher tensile strength (147 MPa) at the combination of welding parameters (1200 rpm, 60 mm/min, and 0.4 mm). The fabrication industries became the great beneficiaries of this emerging technology of the FSW.
Le kit pédagogique LightBox : vers un rapprochement entre physiciens, enseignants et médiateurs autour de projets expérimentaux en optique
Authors: Daussy Christophe
Published: August 2024

Les phénomènes optiques, souvent sources d’émerveillement, constituent un terrain d’expérimentation privilégié pour favoriser l’éveil scientifique. La LightBox est une action conçue pour l’enseignement et la diffusion de la culture scientifique afin d’encourager le développement de projets expérimentaux créatifs en optique. Elle vise à rapprocher les acteurs de l’enseignement supérieur, de la recherche et les enseignants, animateurs et médiateurs scientifiques.
Impact of Donor, Host, and Surgical Parameters on High Endothelial Cell Density More Than 5 Years after Penetrating Keratoplasty
Authors: Sneyers Albéric , Daas Loay , Zemova Elena , Quintin Adrien , Munteanu Cristian , Seitz Berthold
Published: August 2024

Objectives To investigate the correlation between postoperative endothelial cell loss (ECL) and donor, host, and surgical parameters, and to assess the clinical impact of maintaining a high endothelial cell density (ECD) of ≥ 1500 cells/mm2 5 years after penetrating keratoplasty (PKP).

Methods This retrospective cohort study included 216 eyes with 5 years of follow-up, of which 94 had annual visits, and who underwent normal-risk elective PKP for noninfectious indications by one corneal microsurgeon (B. S.) between 2009 and 2016.

Results Among the 216 eyes, ECL (39.1%) over 5 years postoperative exhibited weak positive correlations with storage solution time (p = 0.024) and postmortem time (p = 0.028), and moderately positively correlations with the preoperative ECD (p < 0.001). The 5-year postoperative ECL differed significantly between in domo-prepared (36.8%) and ex domo donor corneas (46.3%; p = 0.001). In the 94 eyes, no significant differences were found between the two groups for central pupil pachymetry (CCT) and BCVA (p > 0.074). However, CCT increased significantly between 1 and 4 years (p = 0.034) and 1 and 5 years postoperatively (p = 0.012), respectively. BCVA improved significantly at 1 year postoperatively and continued to improve until 2 years postoperatively (p < 0.001).

Conclusion The Lions corneal bank Saar-Lor-Lux achieved a significantly reduced ECL (36.8%) over 5 years compared to ex domo donor corneas (46.3%). A weak positive correlation was found between ECL with the storage solution time and the postmortem time, as well as a moderate positive correlation with the preoperative ECD. Although CCT increased significantly over 5 years, BCVA improved significantly from the first to the second postoperative year and remained stable thereafter.
Efficacy and safety of radial incision and cutting for nonsurgical refractory benign esophageal stricture
Authors: Mitani Yosuke , Hirohashi Kenshiro , Tamaoki Masashi , Yokoyama Akira , Katada Chikatoshi , Ueda Aya , Yamahigashi Natsuko , Higuchi Hirokazu , Muto Manabu
Published: August 2024

Background and study aims Radial incision and cutting (RIC) was established to improve refractory esophageal anastomotic strictures but its efficacy and safety for nonsurgical refractory strictures remain unclear. To evaluate the usefulness of RIC in nonsurgical refractory strictures, we retrospectively compared outcomes between nonsurgical and surgical strictures.

Patients and methods We retrospectively studied 54 consecutive patients who were initially treated with RIC for refractory benign esophageal stricture. The study variables included dysphasia score improvement rate, frequency of repeated RIC, cumulative patency rate, cumulative stricture improved rate, and adverse events(AEs), which were compared between nonsurgical (n = 21) and surgical (n = 33) stricture groups.

Results Immediately after RIC, 90.5% of patients in the nonsurgical group and 84.8% of patients in the surgical group had improvement in dysphagia (P = 0.69). The frequency of intervening repeated RIC was 42.9% in the nonsurgical group and 42.4% in the surgical group (P = 0.98). During median follow-up of 22.3 months (range, 1.0–175.0), the cumulative patency rate (P = 0.23) and cumulative stricture improvement rate (P = 0.14) but there was not statistical difference between the two groups. Despite a low cumulative stricture improvement rate (9.5%) at 6 months after the first RIC in the nonsurgical group, 57.7% of patients no longer required endoscopic balloon dilatation at 2 years. The cumulative stricture improvement rate was significantly lower in patients with a history of radiation therapy. No severe AEs were observed in the nonsurgical group.

Conclusions RIC for nonsurgical refractory benign esophageal
stricture is an effective and safe treatment option.
Predictors of Extended Length of Stay Following Open Reduction and Internal Fixation for Distal Radius Fractures
Authors: Smolev Emma , Sriram Varun , Kim Matthew , Kennedy John , Leatherwood William , Komatsu David E. , Wang Edward D.
Published: August 2024

Background An extended length of stay (eLOS) following open reduction and internal fixation (ORIF) for distal radius fractures has been associated with increased patient morbidity and health care costs. The primary objective of this study was to identify risk factors, including patient characteristics, comorbidities, and postoperative complications, which are associated with an eLOS following ORIF for distal radius fractures.

Methods All patients who underwent ORIF for distal radius fractures between 2015 and 2021 were queried from the American College of Surgeons National Surgical Quality Improvement Program database. Postoperative complications were reported within 30 days of procedure. eLOS was defined by ≥3 days from operation to discharge. We identified a total of 26,138 patients and 5.1% (1,323) of patients had an eLOS. Multivariate logistic regression, adjusted for all significantly associated variables, was employed to identify predictors of eLOS following ORIF.

Results Characteristics of patients significantly associated with eLOS were age ≥ 75 (p < 0.001), male gender (p = 0.006), body mass index < 18.5 (p < 0.001), American Society of Anesthesiologists (ASA) ≥ 3 (p < 0.001), dependent functional status (p < 0.001), noninsulin-dependent diabetes (p < 0.001), chronic obstructive pulmonary disorder (COPD) (p < 0.001), ascites (p = 0.005), congestive heart failure (CHF) (p < 0.001), hypertension (p < 0.001), chronic steroid use (p = 0.004), bleeding disorder (p < 0.001), and transfusion ≥ packed red blood cell (pRBC) 72 hours before surgery (p < 0.001). After controlling for significantly associated variables, predictors of eLOS were age ≥ 75 (reference < 65; odds ratio [OR]: 1.34, 95% confidence interval [CI]: 1.24–1.46; p < 0.001), ASA ≥ 3 (OR: 1.79, 95% CI: 1.54–2.01; p < 0.001), male gender (OR: 1.32, 95% CI: 1.13–1.54; p < 0.001), COPD (OR: 1.48, 95% CI: 1.15–1.91; p = 0.003), CHF (OR: 1.94, 95% CI: 1.10–3.42; p = 0.022), bleeding disorder (OR: 1.93, 95% CI: 1.45–2.58; p < 0.001), transfusion ≥ 1 pRBC before surgery (OR: 27.65 95% CI: 58.22–93.02; p < 0.001), bleeding transfusion (OR: 76.70, 95% CI: 15.13–388.81; p < 0.001), septic shock (OR: 13.31, 95% CI: 1.99–88.97; p = 0.008), and nonhome discharge (OR: 34.31, 95% CI: 28.21–41.72; p < 0.001).

Clinical Relevance Age ≥ 75, ASA ≥ 3, male gender, COPD, CHF, bleeding disorder, transfusion pRBC, bleeding transfusion, septic shock, and nonhome discharge were associated with eLOS following ORIF for distal radius fractures.

Level of Evidence Level III; retrospective cohort comparison; prognosis study
Comparison between the Risk of Developing Sleep Disorders with Lung Mechanics and Thoracic Ultrasound Signals in Adults with Obesity
Authors: Silva Sidney Fernandes da , Santos Carlos Eduardo , Fonseca Iasmim Maria Pereira Pinto , Pereira Wellington de Oliveira , Anjos Hendyl Pereira Soares dos , Lopes Agnaldo José
Published: August 2024

Objective The present study aimed to compare the risk of developing sleep disorders with abnormalities in lung mechanics, abnormal ultrasound signals, and anthropometric parameters in adults with obesity.

Materials and Methods A total of 50 individuals were assessed for the risk of obstructive sleep apnea (OSA) using the Mallampati classification, the Epworth Sleepiness Scale (ESS), the Snoring, Tiredness, Observed Apnea, High Blood Pressure, Body Mass Index, Age, Neck Circumference, and Gender (STOP-Bang) questionnaire, and the Sleep Apnea Clinical Score (SACS). Patients also underwent respiratory oscillometry, spirometry, and thoracic ultrasound.

Results The subgroup with abnormal respiratory oscillometry was more likely to have an ESS score indicating a high risk of developing OSA (87.5%) than the subgroup with normal respiratory oscillometry (42.9%) (p = 0.024). On thoracic ultrasound, the frequency of patients with a Mallampati classification of high risk of developing OSA was greater in the subgroup with > 2 B-lines (80%) than in the subgroup with ≤ 2 B-lines (25.7%) (p = 0.0003). The subgroup with subpleural consolidations was more likely to have an OSA-indicative ESS score (100%) than the subgroup without subpleural consolidations (41.9%) (p = 0.004). According to the multivariate analysis, > 2 B lines and body mass index were found to be independent variables for predicting the Mallampati classification, while subpleural consolidation was the only independent variable for predicting the ESS score.

Conclusion In adults with obesity, the greater the risk of developing OSA was, the worse the resistive and reactive parameters measured by respiratory oscillometry. Abnormal respiratory oscillometry and abnormal thoracic ultrasound are factors associated with a high risk of developing OSA.
CrysFormer: Protein structure determination via Patterson maps, deep learning, and partial structure attention
Authors: Pan Tom , Dun Chen , Jin Shikai , Miller Mitchell D. , Kyrillidis Anastasios , Phillips George N.
Published: August 2024

Determining the atomic-level structure of a protein has been a decades-long challenge. However, recent advances in transformers and related neural network architectures have enabled researchers to significantly improve solutions to this problem. These methods use large datasets of sequence information and corresponding known protein template structures, if available. Yet, such methods only focus on sequence information. Other available prior knowledge could also be utilized, such as constructs derived from x-ray crystallography experiments and the known structures of the most common conformations of amino acid residues, which we refer to as partial structures. To the best of our knowledge, we propose the first transformer-based model that directly utilizes experimental protein crystallographic data and partial structure information to calculate electron density maps of proteins. In particular, we use Patterson maps, which can be directly obtained from x-ray crystallography experimental data, thus bypassing the well-known crystallographic phase problem. We demonstrate that our method, CrysFormer, achieves precise predictions on two synthetic datasets of peptide fragments in crystalline forms, one with two residues per unit cell and the other with fifteen. These predictions can then be used to generate accurate atomic models using established crystallographic refinement programs.
Well-posedness and decay structure of a quantum hydrodynamics system with Bohm potential and linear viscosity
Authors: Plaza Ramón G. , Zhelyazov Delyan
Published: August 2024

In this paper, a compressible viscous-dispersive Euler system in one space dimension in the context of quantum hydrodynamics is considered. The purpose of this study is twofold. First, it is shown that the system is locally well-posed. For that purpose, the existence of classical solutions which are perturbation of constant states is established. Second, it is proved that in the particular case of subsonic equilibrium states, sufficiently small perturbations decay globally in time. In order to prove this stability property, the linearized system around the subsonic state is examined. Using an appropriately constructed compensating matrix symbol in the Fourier space, it is proved that solutions to the linear system decay globally in time, underlying a dissipative mechanism of regularity gain type. These linear decay estimates, together with the local existence result, imply the global existence and the decay of perturbations to constant subsonic equilibrium states as solutions to the full nonlinear system.
Group foliations of the β-plane barotropic vorticity equation
Authors: Kaptsov E. I.
Published: August 2024

Despite the large number of publications on symmetry analysis of the barotropic vorticity equation on the β-plane, its group foliations have not been considered previously. The present publication aims to address this shortcoming. Group foliations are constructed for the equation, and based on them, invariant solutions are derived, some of which generalize previously known exact analytical solutions. There is also a discussion of the pros and cons of the group foliation approach including consideration of some numerical issues.
On density functional theory models for one-dimensional homogeneous materials
Authors: Bensiali Bouchra , Lahbabi Salma , Maichine Abdallah , Mirinioui Othmane
Published: August 2024

This paper studies Density Functional Theory (DFT) models for homogeneous 1D materials in the 3D space. It follows the previous work [Gontier et al., Commun. Math. Phys. 388, 1475–1505 (2021)] about DFT models for homogeneous 2D materials in 3D. We show how to reduce the problem from a 3D energy functional to a 2D energy functional. The kinetic energy is treated as in the 2D material case by diagonalizing admissible states, and writing the kinetic energy as the infimum of a modified kinetic energy functional on reduced states. Besides, we treat here the Hartree interaction term in 2D, and show how to properly define the mean-field potential, through Riesz potential. We then show the well-posedness of the reduced model and present some numerical illustrations.
Numerical design and experimental validation of shockless plate impact configurations for the Lagrangian analysis of armor ceramics
Authors: Genevois Julia , Forquin Pascal , Zinszner Jean-Luc
Published: August 2024

Ceramic materials are widely used in armor or protective structures, providing weight saving at equivalent performance in comparison to their steel counterparts. Plate-impact experiments are commonly used to investigate the dynamic behavior of ceramics under compressive loading. Using the particle velocity measured at the back of the target, some mechanical properties such as the Hugoniot elastic limit (HEL) as well as the Hugoniot curve of the material can be deduced. Nevertheless, these tests do not provide a direct measurement of the plastic hardening (post-HEL) behavior of the target. In the present work, an experimental shockless plate-impact configuration was developed and implemented to conduct a Lagrangian analysis. This configuration relies on the use of a wavy-machined flyer plate impacting a target made of a buffer, two ceramic plates of different thicknesses, and two window plates as backing. First, the use of wavy flyer plates to generate a loading ramp was validated by considering the impact of the wavy-machined flyer plate against a target, both made of 316L steel. A numerical analysis of this test was developed to confirm the pulse-shaping effect observed experimentally. Next, a ceramic, F99.7 alumina was subjected to the shockless plate impact test in Lagrangian configuration considering the same steel as a buffer and flyer plate material. These tests coupled with Lagrangian analysis enable the curve of axial-stress vs axial-strain beyond the isentropic elastic limit (IEL) to be deduced. The experimental data allow identifying the parameters of an elastoplastic with strain-hardening model to describe the behavior of the tested alumina.
Dynamical integrity of the safe basins in a problem of forced escape
Authors: Kravetc Pavel , Gendelman Oleg , Fidlin Alexander
Published: August 2024

This paper explores the use of the approximation of isolated resonance method for determining the safe basins (SBs) in the problem of escape from a potential well. This study introduces a novel approach to capture the location and shape of the SBs and establish their erosion profiles. This research highlights the concept of “true” safe basins, which remain invariant with phase shifts, a critical factor often faced in real-world applications. A cubic polynomial potential serves as the benchmark to illustrate the proposed method.
A new four-dimensional chaotic system with rich transitional characteristics between dissipative and conservative
Authors: Sun Xu , Leng Xiangxin , Tian Bowen , Du Baoxiang
Published: August 2024

The general form of the Hamiltonian function serves as the foundation for the creation of a new four-dimensional chaotic system in this study. We discover that the external excitation parameter d, the internal parameter a, and all initial values have a transforming influence on the system property. Additionally, the corresponding fractional-order chaotic system in accordance with the constructed four-dimensional chaotic system is proposed. It is found that as the order q rises, the system transforms gradually from a dissipative system to a conservative system. Multiple coexisting attraction flows based on the Hamiltonian energy magnitude are present in this dual-property chaotic system. The complexity analysis shows that the system has a high level of complexity. NIST test indicates that the chaotic sequences produced by this dual-property chaotic system exhibit good pseudo-randomness. Finally, a Digital Signal Processing-based hardware platform confirms the physical realizability of the system.
Enhanced electrical performance in graphene field-effect transistors through post-annealing of high-k HfLaO gate dielectrics
Authors: Liu Chunlin , Li Xuesong , Qian Ling-Xuan , Tian Jing , Zhang Xiping
Published: August 2024

High-k gate dielectrics have attracted a great deal of attention in the investigation of transistors due to their unique properties such as superior gate controllability. However, their integration into graphene field-effect transistors (GFETs) remains problematic and the physical mechanisms governing the performance of these devices are still not fully understood. In this study, the effects of post-annealing on GFETs utilizing the high-k HfLaO ternary oxide as the gate dielectric were comprehensively investigated. The HfLaO film was deposited on top of graphene by magnetron sputtering, and the device performance with various post-annealing temperatures was conducted. It was found that post-annealing temperature can effectively increase the dielectric constant through balancing the oxygen-vacancy defects and moisture absorption. Both the surface morphology of HfLaO and performance of GFETs were investigated, and the fabricated GFETs exhibit notable electrical performance enhancements. Specifically, GFETs with a 200 °C post-annealed HfLaO gate dielectric demonstrate the optimal device performance, featuring a minimal Dirac point voltage (VDirac) of 1.1 V and a minimal hysteresis (ΔVDirac) of 0.5 V. The extracted hole and electron mobilities are 4012 and 1366 cm2/V · s, respectively, nearly one order of magnitude higher than that of GFETs with as-deposited HfLaO. This work outperforms other existing GFETs utilizing high-k gate dielectric and chemical vapor deposition grown graphene in terms of both carrier mobility and on–off ratio. It is also noted that the excessive post-annealing temperature can negatively impact the GFET performance through introducing oxygen vacancies, increasing the surface roughness, lowering the breakdown voltage, and inducing recrystallization.
Load-dependent optical coherence tomography attenuation imaging: How tissue mechanics can influence optical scattering
Authors: Gong Peijun , Boman Imogen , Zilkens Renate , Yeomans Chris , Hardie Mireille , Rijhumal Anmol , Saunders Christobel M. , Kennedy Brendan F.
Published: August 2024

Mechanical load imparted to tissue, for example via handheld imaging probes, leads to tissue deformation, altering the distribution of tissue microstructure and, consequently, attenuation of light and image formation in optical imaging. In mechanically heterogeneous tissue, the load can result in spatially varying deformation and, therefore, spatially varying changes in the attenuation of light, which may provide additional image contrast. To investigate this potential, an assessment of the spatially resolved impact of mechanical deformation of the tissue on optical imaging is critical; however, it is challenging to incorporate stress mapping into optical imaging without obscuring the detection of photons. To address this, we present the novel integration of stress imaging using optical palpation with attenuation imaging based on optical coherence tomography (OCT). The method was implemented using a compliant silicone sensor incorporated into a custom handheld OCT probe, providing two-dimensional stress imaging with concurrent attenuation imaging. Attenuation imaging with varying mechanical loads was demonstrated on 19 tissue regions acquired from eight freshly excised human breast specimens. The results demonstrated distinct characteristics for different breast tissue types: benign stroma showed relatively large increases in attenuation (e.g., ∼0.3 to 0.4 mm−1/kPa) over a low stress range (∼2 to 10 kPa), while cancerous tissue showed markedly small increases in attenuation (e.g., ∼0.005 to 0.02 mm−1/kPa) mainly over a medium to high stress range (∼10 to 90 kPa). The integration of stress imaging with attenuation imaging provided a pilot assessment of the spatially resolved impact of tissue mechanical heterogeneity on optical attenuation, providing novel image contrast by encoding variations in mechanical properties on optical attenuation in tissue.
The hydraulic fracture propagation pattern induced by multi-stage temporary plugging and diverting fracturing in reservoirs with various lithologies: An experimental investigation
Authors: Zhou Hang , Zhang Li , Zhang Kaixuan , Shi Guanghao , Wang Bo , Zhou Fujian
Published: August 2024

Multi-stage temporary plugging and diverting fracturing (TPDF) is an effective method for generating hydraulic fracture (HF) networks. This study investigates various lithological reservoirs in the Xinjiang region, obtaining downhole full-diameter cores for experimental analysis using true triaxial TPDF. The characteristics of HF morphology are quantitatively assessed by employing computed tomography (CT) scanning. The findings are summarized as follows: (1) Initial hydraulic fracturing of specimens with different lithologies results in σH-direction double-wing HF, while the first TPDF generates a single-wing HF along the σh direction, and the second TPDF produces a single-wing HF along the σH direction. (2) The volume and area of HFs in the first TPDF of volcanic rock increased by over 30%. The first TPDF effect is more pronounced in conglomerate rock, with HF volume over 25% and surface area increasing by more than 35%. (3) During multi-stage TPDF, volcanic rock transitions from initial HF to the formation of new HF, sandstone diverts from the wellbore to create new HF, and conglomerate generates new HF through multi-point initiation in the wellbore and HF. Each TPDF process involves the propagation of existing HFs and the generation of new ones. (4) The breakdown pressure in multi-stage TPDF increased by 46.5% and 51.6% in volcanic rock, while in sandstone, the first TPDF increased by 90.6%. In conglomerate rock, multi-stage TPDF saw increases of 51.2% and 41.9%, respectively. These findings offer theoretical insights for optimizing TPDF design in diverse lithological reservoirs.
The crucial role of diagnostics in achieving ignition on the National Ignition Facility (NIF)
Authors: Kilkenny J. D. , Pak A. , Landen O. L. , Moore A. S. , Meezan N. B. , Haan S. W. , Hsing W. W. , Batha S. H. , Bradley D. K. , Gatu-Johnson M. , Mackinnon A. J. , Regan S. P. , Smalyuk V. A.
Published: August 2024

Well over 100 diagnostics can operate on the National Ignition Facility (NIF) as a result of several decades of development on NIF, and before that on Nova, OMEGA, and earlier LLNL lasers. A subset of these have guided the approach to achieving ignition on the NIF in 2022 [H. Abu-Shawareb et al. (Indirect Drive ICF Collaboration), Phys. Rev. Lett. 129(7), 075001 (2022)]. Achieving ignition on NIF has required many types of experiments with this core set of diagnostics, some constraining known unknowns and some revealing surprises—arguably unknown unknowns. Early design work realized that the extreme precision required for ignition on NIF would require fine-tuning by experiment, that is, measuring and adjusting known unknowns. Many examples are given where the use of the core set of ignition diagnostics in experimental arrangements called platforms demonstrated control of the key theoretical parameters defined as shape, adiabat, velocity, and mix. The direction of the adjustments to input conditions is found either by trend analysis or, in many cases, by observing from the diagnostic data the direction to make an adjustment. In addition, diagnostics have revealed some unexpected or neglected known issues, which degrade performance, or unexpected issues, unknown unknowns. Some of these factors had been previously considered, but underestimated or difficult to calculate at the time. The overall methodology can be described as a variant of Popper's falsifiability philosophy [K. Popper, The Logic of Scientific Discovery (Hutchinson, 1974)]. This paper summarizes the role of ignition diagnostics in terms of falsification or validation of theory or experimental setup as well as uncovering unexpected issues. The journey to ignition started in the seventies with a 1-µm wavelength laser producing disastrous results. Diagnostics have guided us to the recent multi-decadal goal of demonstrating ignition and burn in the laboratory.
Role of charge injection/de-trapping in imprint behavior of ferroelectric Hf0.5Zr0.5O2 thin film
Authors: Liu Zhenhong , Toprasertpong Kasidit , Cai Zuocheng , Takenaka Mitsuru , Takagi Shinichi
Published: August 2024

Ferroelectric HfO2-based thin films have attracted increasing interest due to their potential applications in nonvolatile memory areas. However, their unique properties, such as imprint, lead to serious reliability issues. In this study, the origin of imprint behavior is investigated by using TiN/Hf0.5Zr0.5O2 (10 nm)/TiN MFM capacitors. By modulating the internal electric field during imprint, we discover that charge injection/de-trapping in metal–ferroelectric interfaces plays an essential role in imprint behavior rather than charge movement inside the FE layer. The asymmetric shift of the coercive field is also discussed, which is attributed to nonlinear interaction between polarization's bound charges and the electrode's screening charges. This suggests that controlling interface quality should effectively suppress imprint in HfO2-based thin films.
Impingement of vortex dipole on heated boundaries and related thermal plume dynamics
Authors: Kandre Shivakumar , Hari Prasad P. , Patil Dhiraj V.
Published: August 2024

The profound influence of an externally induced vortex dipole on thermal plume dynamics is numerically studied for varying Rayleigh numbers (Ra) employing the Bhatnagar–Gross–Krook collision model-based lattice Boltzmann method with a double distribution function approach. This study is extended to vortex dipole impingement with different types of heated bottom boundaries of two-dimensional domain, such as flat, “V-shaped,” and “inverted-V-shaped.” The vortex dipole impingement with the heated boundaries generates secondary vortices, which in turn produce vortex-driven thermal plumes, thereby advancing plume generation. The subsequent merging of the plumes enhances heat transport and leads to a continuous plume ascent. The presence of convex corners facilitates flow separation and also gives rise to the formation of secondary vortex dipoles, thereby significantly impacting the continuous generation of jet-like plumes when compared to concave configurations. The lack of an external vortex in pure buoyancy-driven flows produces less pronounced jet-like plumes and a relatively low Nusselt number. The boundary types and Ra significantly influence the vorticity production, resulting in higher enstrophy and palinstrophy for convex boundaries compared to flat and concave ones. A lower Prandtl number increases secondary vortices and corner rolls, leading to larger velocity gradients, higher thermal diffusivity, resulting in increased kinetic energy and thermal dissipation rates. The increased cell height enhances heat transfer at the top boundary due to improved heat convection from the slanted boundary and influence of early dipole impingement. Furthermore, kinetic energy dissipates in the dipole-driven flows and increases in the buoyancy-dominated flows.
Self-propulsion of a Quincke droplet on a superhydrophobic wall under low electric Reynolds number ReE≤ 1
Authors: Xie Zonglu , Dong Qingming , Sau Amalendu , Wang Zhentao
Published: August 2024

A rotating object placed on a wall can generate an additional translating motion. Inspired by this phenomenon, we unfold a novel approach to the self-propulsion of a Quincke rotating drop in the current two-dimensional numerical simulation based on the resting wall effect. Accordingly, the impact of two controlling variables, the electric field strength E0* and viscosity ratio λ, is examined in detail for a Quincke drop resting on a superhydrophobic wall. We consider a fixed conductivity ratio and permittivity ratio to (i) explore the dynamic activities of the droplet to verify the proposed self-propulsion scheme and (ii) reveal the physical propelling mechanism. Our results show that the Quincke drop displays three distinct states. (I) Taylor state (where the symmetry in dynamic behaviors is the primary indicator). (II) Transition stage from a Taylor regime to the Quincke regime, when the symmetry is broken and the created asymmetric flow causes the droplet to detach from the wall. At this stage, the tuned controlling parameters led to diverse droplet detachment processes, significantly influencing the subsequent self-propulsion. Additionally, based on the droplet behaviors in the transition stage for 6.78 < E0* ≤ 57.63 at fixed λ = 50, three distinct propulsion patterns are discovered: one-way propulsion for 6.78 < E0* < 9.5, round trip propulsion for 9.5 ≤ E0* < 33.9, and liquid film-breakup propulsion for 33.9 ≤ E0* ≤ 57.63. (III) Self-propulsion stage. Here, the levitated droplet entrains the bulk fluid into the bottom, preventing its re-depositing on the wall by creating a liquid cushion between the Quincke rotating drop and the wall. This thin liquid cushion generates a higher viscous stress at the droplet's bottom, causing a significant velocity difference between its upper and lower halves. This velocity difference produces the crucial horizontal translation for the rotating droplet, i.e., the self-propulsion. Moreover, the liquid cushion's thickness (h*) affects the translation velocity. A higher E0* or λ leads to a smaller h* and expedites the droplet translation.
Experimental study of the effect of the ventilation mode on the water-exit of the vehicle
Authors: Zhang Qing-Sen , Ming Fu-Ren , Liu Chang , Zhu Yi-Heng , Zhang A-Man
Published: August 2024

The water-exit problem of active ventilation vehicles has complex cavity dynamics and hydrodynamic characteristics. This study explores the influence of the ventilation parameters on the dynamic evolution of the cavity and the hydrodynamic forces by experimentation. The full development of cavities is beneficial for hydrodynamic stability. The ventilation parameters focus on two influencing factors: the ventilation opening type and the ventilation angle between the direction of gas flow and the axis of the vehicle. The former includes porous structure, ventilation hole, and ventilation seam, while the latter includes 30° and 90°. Compared to the cases of holes and seams, the cavities formed under the porous structure opening condition have larger diameters and shorter lengths. This is not conducive to the hydrodynamic performance, which includes frictional resistance, pressure drag, and impact pressure at the closure point. When the cavity transits from a partial state to a supercavity state, the frictional resistance no longer changes significantly, and the axial drag coefficient tends to be stable. The increase in the cavity diameter leads to an increase in the pressure drag and the impact pressure at the cavity closure. The ventilation angle mainly affects the stability of the internal pressure and the morphology of the cavity. This work can provide reference for the design of artificial cavity of underwater vehicles.
Conversion mechanism of the atomically precise group IB metal nanoclusters by theoretical calculations
Authors: Lv Ying , Nie Wan , Yu Haizhu , Zhu Manzhou
Published: August 2024

The controllable synthesis and design of group IB metal (i.e., Au/Ag/Cu) and their alloy nanoclusters (IB-NCs) rely on an elucidation of the conversion mechanism, bonding preference, and structure–property relationships. In the past decades, the development of cluster-to-cluster transformation and spectroscopic tracking strategy have provided important mechanistic insights that greatly help researchers improve synthetic skills and explore the application of IB-NCs. Specifically, with the aid of DFT calculations, the structural information of cluster-to-cluster conversion, including the intermediates and active sites, can be deduced from the atomic level. In this review, the conversion mechanisms of IB-NCs in the past three years have been reviewed to summarize the key factors influencing structural transformation and reactivity. The three types of cluster-to-cluster conversion (i.e., foreign metal source, foreign ligand, and other reagents/condition-induced conversion) were highlighted for further synthesis and design of functional nanoclusters.
Effects of submergence ratio on flow around a circular pier in combined wave–current flows using particle image velocimetry
Authors: Aravind Jagilinki , Eldho T. I. , Mazumder B. S.
Published: August 2024

The present study illustrates an experimental investigation of flow hydrodynamics in the vicinity of a submerged circular pier across various submergence levels under only current and wave–current combined flow conditions. The instantaneous velocity data are collected using particle image velocimetry for three distinct frequencies of waves to determine the influence of wave superimposition on the current-induced turbulence parameters. The distribution of phase averaged turbulence quantities, such as mean velocities, Reynolds shear stress, turbulent kinetic energy, flow patterns, and vorticity analysis by Q-criterion, are presented. The results provide insight into the impacts of wave frequency and submergence ratio on the formation of horseshoe vortices, trailing vortex, and reverse flow zones. From the results it is observed that a decrease in the submergence level of the structure causes the formation of strong horseshoe vortices and reverse flow zones in the absence of waves. Also, an increase in wave frequency intensifies the turbulence kinetic energy at the upstream of the pier and eddy generation behind the pier. The present findings highlight the effects of pier submergence and wave characteristics, such as frequency, wave height, and wave period, on flow patterns and turbulent flow characteristics and aid in the design of marine structures. Furthermore, experimental data serve as a valuable resource for validating theoretical or mathematical models related to combined wave–current environments.