bluuebunny/crossref_metadata_2025 huggingface dataset:
Energy management strategy of fuel cell electric vehicle based on work condition recognition
Authors: ZHANG Zelong , HUANGFU Yigeng , WEI Jiang
Published: October 2024

To reduce hydrogen consumption in fuel cell electric vehicles, mitigate power fluctuations, and maintain the battery system's state of charge, a novel transition process recognition method based on work condition recognition framework of energy management strategy is proposed. This method offers the advantages such as higher recognition rates and faster recognition speed comparing with the traditional condition recognition methods. A comparison is made with the commonly used LVQ recognition method, and the simulations are conducted to demonstrate the superiority of this condition recognition algorithm and the improved performance of the energy management strategy based on the present recognition method under mixed work conditions.
Kutane Sarkoidose
Authors: Schauer Franziska , Diehl Rebecca
Published: October 2024

Die Sarkoidose ist eine Multisystemerkrankung, deren Ursache bislang ungeklärt ist. Pathognomonisch sind nicht verkäsende Granulome, die alle Gewebe oder Organsysteme betreffen können. Aufgrund der guten klinischen Sichtbarkeit der kutanen Sarkoidose ist diese oft der erste Hinweis für das Vorliegen einer systemischen Sarkoidose. Die Dermatologie spielt somit eine wichtige Rolle bei der Früherkennung dieser multisystemischen Erkrankung. Eine reine Hautmanifestation ohne systemische Beteiligung ist möglich. Die häufigsten Vertreter hierfür sind die makulopapulöse und die noduläre Sarkoidose. Zum anderen gibt es unspezifische Hautmanifestationen, wie zum Beispiel das Erythema nodosum, welches im Rahmen einer systemischen Sarkoidose auftreten kann. Die Diagnose wird mittels Gewebebiopsie gestellt. Die Biomarker CRP, sIl-2R und Neopterin können bei Hautmanifestation Hinweis für eine systemische Beteiligung sein. Die Therapie richtet sich nach Schwere der Hautmanifestation und systemischer Beteiligung. Zur Behandlung der kutanen Sarkoidose zugelassen sind topische, intraläsionale oder systemische Glukokortikosteroide. Bei therapierefraktären Verläufen können off-label immunmodulierende oder immunsuppressive Medikamente eingesetzt werden.
Zaungast in der Kniekehle
Authors: Zhang Zheng
Published: October 2024

Bei der Baker-Zyste handelt es sich um eine flüssigkeitsgefüllte Ausstülpung der Gelenkkapsel hinter dem Knie, meist infolge von Überlastung, Verletzung oder Knieerkrankungen wie Arthritis oder Arthrose. In der Traditionellen Chinesischen Medizin (TCM) gelten als ursächliche pathologische Faktoren unter anderem Nässe und Kälte, Blutstagnation im Blasenmeridian sowie Leber- und Nierenschwäche. Zu den wichtigen Akupunkturpunkten – auch im besprochenen Fall – zählen insbesondere die Ashi-Punkte „Drachen umzingeln“, Lokal- und Regionalpunkte auf dem Blasenmeridian und bewährte Fernpunkte, die nach pathologischem Muster und Schmerzausstrahlung ausgewählt werden.
Gute Lösungen
Authors: Stern Cornelia
Published: October 2024

Für die Wahl des richtigen Auszugsmediums einer Heilpflanzenzubereitung ist das Löslichkeitsverhalten der wirksamkeitsbestimmenden Inhaltsstoffe entscheidend. Am Beispiel der wichtigsten Pflanzenwirkstoffe wird die Löslichkeit in Wasser (Infus und Dekokt), Ethanol (Tinktur) und Öl (Ölauszug) dargestellt. Im Fokus stehen Gerbstoffe, Bitterstoffe, ätherische Öle, Saponine und Flavonoide und ihre jeweiligen Untergruppen.
Novel Approach to Identify Severe Maternal Morbidity Clusters: A Latent Class Analysis
Authors: Ibarra Andrea J. , Lopa Samia H. , Phan BaDoi N. , Himes Katherine , Butters Meryl A. , Beck Stacy , Catov Janet M.
Published: October 2024

Objective Whether clusters exist within severe maternal morbidity (SMM), a set of life-threatening heterogeneous conditions, is not known. Our primary objective was to identify SMM clusters using a data-driven clustering technique, their associated predictors and outcomes.

Study Design From 2008 to 2017, we used a delivery database supplemented by state data and medical record abstraction from a single institution in Pennsylvania. To identify SMM clusters, we applied latent class modeling that included 23 conditions defined by 21 Centers for Disease Control SMM indicators, intensive care unit (ICU) admission, or prolonged postpartum length of stay. Logistic regression models estimated risk for SMM clusters and associations between clusters and maternal and neonatal outcomes.

Results Among 97,492 deliveries, 2.7% (N = 2,666) experienced SMM by any of the 23 conditions. Four clusters were identified as archetypes of SMM. Deliveries labeled as Hemorrhage (37.7%, N = 1,004) were characterized by blood transfusions and sickle cell anemia; Critical Care (28.1%, N = 748) by ICU admission and amniotic embolism; Vascular (24.5%, N = 654) by cerebrovascular conditions; and Shock (9.8%, N = 260) by ventilatory support and shock. Hypertensive disorders of pregnancy, depression, and Medicaid insurance were associated with Shock cluster. People in all clusters had a high risk of maternal death within 1 year (odds ratio: 12.0, 95% confidence interval: 6.2–23). Infants born to those in the shock cluster had the highest odds of neonatal death, low Apgar scores, and neonatal ICU admission.

Conclusion We identified four novel SMM clusters that may help understand the collection of conditions defining SMM, underlying pathways and the importance of comorbidities such as depression and social determinants of health markers that amplify the well-established risk factors for SMM such as hypertensive disorders of pregnancy.

Key Points
Clinical Analysis of Inhaled Nitric Oxide Therapy in Preterm Infants at Different Gestational Ages: A National Retrospective Multicenter Study
Authors: Liang Guo-bao , Wang Lian , Huang Sheng-qian , Feng Bao-ying , Yao Mu-lin , Fan Xu-fang , Wang Meng-jiao , Zhu Lu , Zhang Jing , Zheng Zhi , Zhu Yao , Shen Wei , Duan Wen-li , Mao Jian , Wu Fan , Li Zhan-kui , Xu Fa-lin , Ma Li , Wei Qiu-fen , Liu Ling , Lin Xin-zhu
Published: October 2024

Objective This study aimed to investigate clinical features of inhaled nitric oxide (iNO) in preterm infants with a gestational age (GA) < 34 weeks in China.

Study Design The clinical data of 434 preterm infants with GA < 34 weeks, treated with iNO in the neonatology departments of eight Class A tertiary hospitals in China over a 10-year period from January 2013 to December 2022, were included in this retrospective multicenter investigation. The infants were divided into three groups based on GA: 24 to 27 weeks (extremely preterm infants), 28 to 31 weeks (very preterm infants), and 32 to 33 weeks (moderate preterm infants). The use of iNO, perinatal data, incidence and mortality of indication for iNO treatment, therapeutic effects of iNO, incidence of short-term complications for iNO treatment, and mortality were compared among these three groups.

Results Over the past 10 years, the proportion of iNO use was highest in extremely preterm infants each year. The lower the GA, the higher the iNO use rate: 4.20% for GA 24 to 27 weeks, 1.54% for GA 28 to 31 weeks, and 0.85% for GA 32 to 33 weeks. There was no significant difference in the therapeutic effect of iNO among the three groups. The incidence of neonatal pulmonary hemorrhage, neonatal shock, late-onset diseases, retinopathy of prematurity requiring intervention, intracranial hemorrhage (grade 3 or 4), periventricular leukomalacia, neonatal necrotizing enterocolitis (≥stage II), and moderate to severe bronchopulmonary dysplasia was highest in extremely preterm infants and increased with decreasing GA. Mortality was negatively correlated with GA and birth weight. The highest rate of iNO treatment in 24 to 27 weeks' preterm infants was due to hypoxic respiratory failure (HRF), whereas the highest rate of iNO treatment in 32 to 33 weeks' preterm infants was due to documented persistent pulmonary hypertension of the newborn (PPHN). The rates of iNO treatment due to HRF and documented PPHN were 54.3 and 60.6%, respectively, in extremely preterm infants, significantly higher than in very preterm and moderate preterm infants (all p < 0.05). Within the same GA group, the proportion of preterm infants treated with iNO for HRF was lower than that for documented PPHN (all p < 0.05), but there was no statistically significant difference in mortality between HRF and documented PPHN treated with iNO (all p > 0.05).

Conclusion Among preterm infants with GA < 34 weeks, the rate of iNO usage was highest in extremely preterm infants. However, iNO failed to improve the clinical outcome of extremely preterm infants with refractory hypoxemia, and there was no significant difference in the therapeutic effect of iNO among preterm infants with different GAs.
Modulating Immune Responses: The Double-Edged Sword of Platelet CD40L
Authors: Bendas Gerd , Gobec Martina , Schlesinger Martin
Published: October 2024

The CD40–CD40L receptor ligand pair plays a fundamental role in the modulation of the innate as well as the adaptive immune response, regulating monocyte, T and B cell activation, and antibody isotype switching. Although the expression and function of the CD40–CD40L dyad is mainly attributed to the classical immune cells, the majority of CD40L is expressed by activated platelets, either in a membrane-bound form or shed as soluble molecules in the circulation. Platelet-derived CD40L is involved in the communication with different immune cell subpopulations and regulates their functions effectively. Thus, platelet CD40L contributes to the containment and clearance of bacterial and viral infections, and additionally guides leukocytes to sites of infection. However, platelet CD40L promotes inflammatory cellular responses also in a pathophysiological context. For example, in HIV infections, platelet CD40L is supportive of neuronal inflammation, damage, and finally HIV-related dementia. In sepsis, platelet CD40L can induce extensive endothelial and epithelial damage resulting in barrier dysfunction of the gut, whereby the translocation of microbiota into the circulation further aggravates the uncontrolled systemic inflammation. Nevertheless, a distinct platelet subpopulation expressing CD40L under septic conditions can attenuate systemic inflammation and reduce mortality in mice. This review focuses on recent findings in the field of platelet CD40L biology and its physiological and pathophysiological implications, and thereby highlights platelets as vital immune cells that are essential for a proper immune surveillance. In this context, platelet CD40L proves to be an interesting target for various inflammatory diseases. However, either an agonism or a blockade of CD40L needs to be well balanced since both the approaches can cause severe adverse events, ranging from hyperinflammation to immune deficiency. Thus, an interference in CD40L activities should be likely done in a context-dependent and timely restricted manner.
Uniform microwave field formation for control of ensembles of negatively charged nitrogen vacancy in diamond
Authors: Rezinkin Oleg , Rezinkina Marina , Kitamura Takuya , Paul Rajan , Jelezko Fedor
Published: October 2024

The homogeneity of the microwave magnetic field is essential in controlling a large volume of ensemble spins, for example, in the case of sensitive magnetometry with nitrogen-vacancy (NV) centers in diamond. This is particularly important for pulsed measurement, where the fidelity of control pulses plays a crucial role in its sensitivity. So far, several magnetic field-forming systems have been proposed, but no detailed comparison has been made. Here, we numerically study the homogeneity of five different systems, including a planar antenna, a dielectric resonator, a cylindrical inductor, a barrel-shaped coil, and a nested barrel-shaped coil. The results of the simulation allowed us to optimize the design parameters of the barrel-shaped field-forming system, which led to significantly improved magnetic field uniformity. To measure this effect, we experimentally compared the homogeneity of a field-forming system having a barrel shape with that of a planar field-forming system by measuring Rabi oscillations of an ensemble of NV centers with them. Significant improvements in inhomogeneity were confirmed in the barrel-shaped coil.
Equilibrium densities of intrinsic defects in transition metal diselenides of molybdenum and tungsten
Authors: Holtzman Luke N. , Vargas Preston Allen , Hennig Richard G. , Barmak Katayun
Published: October 2024

Point defects are thermodynamically stabilized in all crystalline materials, with increased densities negatively impacting the properties and performance of transition metal dichalcogenides (TMDs). While recent point defect reduction methods have led to considerable improvements in the optoelectronic properties of TMDs, there is a clear need for theoretical work to establish the lower limit of defect densities, as represented by thermal equilibrium. To that end, an ab initio and thermodynamic analysis of the equilibrium densities of intrinsic point defects in MoSe2 and WSe2 is presented. The intrinsic defect formation energies at the limits of the selenium and metal-rich regimes are determined by density functional theory (DFT) and then augmented with elemental chemical potential functions to determine temperature- and pressure-dependent formation energies. Equilibrium defect densities are determined for MSe, SeM, vM, and vSe, where M and v, respectively, represent the metal and the vacancy, as a function of synthesis temperature and pressure. The effects of vibrational free energy contributions and treatment of the DFT exchange–correlation potential are found to be non-negligible. Calculated equilibrium densities are several orders of magnitude below reported defect densities in TMDs made by chemical vapor deposition, chemical vapor transport, and flux methods, thereby establishing that current synthesis methods are either kinetically limited or impurity dominated.
The impact of interface and heterostructure on the stability of perovskite-based solar cells
Authors: Shen Yuxia , Li Chongwen , Liu Cheng , Reitz Samantha Ann , Chen Bin , Sargent Edward H.
Published: October 2024

Perovskite solar cells have made significant progress in achieving high power conversion efficiency (>26%) in the past decade. However, achieving long-term stability comparable to established silicon solar cells is still a significant challenge, requiring further investigation into degradation mechanisms and continued exploration of interface engineering strategies. Here we review stability at the interfaces between perovskite and charge transport layers. These interfaces are particularly vulnerable to defects and degradation under external stresses such as heat, light, and bias, further compounded by their ionic nature and thermal expansion mismatch. To address these issues, strategies such as the use of additives, organic self-assembled monolayers, and low-dimensional perovskites have been developed to improve interface stability. These approaches enhance crystallinity, reduce defect-related recombination, and improve mechanical toughness.
Polarity control and crystalline quality improvement of AlN thin films grown on Si(111) substrates by molecular beam epitaxy
Authors: Fan Shizhao , Yin Yuhao , Liu Rong , Zhao Haiyang , Liu Zhenghui , Sun Qian , Yang Hui
Published: October 2024

We attain N-polar and Al-polar AlN thin films on Si(111) substrates by plasma-assisted molecular beam epitaxy. The polarity of AlN epilayers has been validated by wet chemical etching using tetramethylammonium hydroxide and by the direct cross-sectional observation of atomic stacking under high-angle annular dark-field scanning transmission electron microscopy. For the 290 nm-thick as-grown N-polar AlN epilayer, x-ray diffraction (XRD) (002) and (102) ω rocking curve peak full width half maximums (FWHMs) are 475 and 1177 arcsec, and the surface mean square roughness (RMS) is 0.30 nm. We flipped the polarity using the metal-flux-modulation-epitaxy (MME) strategy. The MME strategy promotes anti-phase boundaries (APBs) on the {22¯01} crystalline planes instead of commonly observed lateral planar APBs in AlN epilayers. Merging of the tilted APBs at ∼50 nm leads to a complete Al-polar surface. For the 180 nm-thick Al-polar AlN epilayer, XRD (002) and (102) peak FWHMs are 1505 and 2380 arcsec, and the surface RMS is 1.41 nm. Strain analysis by XRD and Raman spectroscopy indicates a uniform tensile strain of 0.160% across the N-polar AlN epilayer surface and a strain distribution of 0.113%–1.16% through the epilayer. In contrast, the Al-polar AlN epilayer exhibits a much broader tensile strain distribution of 0.482%–2.406% along the growth direction, potentially due to the interaction of polarity inversion and strain relaxation.
No more gap-shifting: Stochastic many-body-theory based TDHF for accurate theory of polymethine cyanine dyes
Authors: Bradbury Nadine C. , Li Barry Y. , Allen Tucker , Caram Justin R. , Neuhauser Daniel
Published: October 2024

We introduce an individually fitted screened-exchange interaction for the time-dependent Hartree–Fock (TDHF) method and show that it resolves the missing binding energies in polymethine organic dye molecules compared to time-dependent density functional theory (TDDFT). The interaction kernel, which can be thought of as a dielectric function, is generated by stochastic fitting to the screened-Coulomb interaction of many-body perturbation theory (MBPT), specific to each system. We test our method on the flavylium and indocyanine green dye families with a modifiable length of the polymethine bridge, leading to excitations ranging from visible to short-wave infrared. Our approach validates earlier observations on the importance of inclusion of medium range exchange for the exciton binding energy. Our resulting method, TDHF@vW, also achieves a mean absolute error on a par with MBPT at a computational cost on a par with local-functional TDDFT.
ADCHα-I population analysis and constrained dipole moment density functional theory in force fields for molecular simulations
Authors: Carmona-Espíndola Javier , García-Melgarejo Valeria , Núñez-Rojas Edgar , Mendoza Samantha , García Abraham , Gázquez José L. , Alejandre José
Published: October 2024

A new population analysis, ADCHα-I, based on the interpolation between the Hirshfeld (H) and the iterative Hirshfeld (H-I) methods through a parameter α and on the atomic dipole moment corrected Hirshfeld (ADCH) methodology is proposed, in combination with the constrained dipole moment density functional theory (CD-DFT) previously developed, to determine the charge distributions of force fields. Following this approach, the electronic density of the isolated molecule is determined for the value of the dipole moment that reproduces the experimental dielectric constant, in order to incorporate through this property the effects of the surrounding molecules in the liquid, and to carry on this information to the molecular simulation, the new population analysis is built to obtain the set of charges that reproduces this dipole moment. By selecting α = 1/2, one is led to charges that are larger than the ones obtained through H and ADCH and smaller than those of H-I and that incorporate, at the local level, information about the response of isolated atoms to donate or to accept charge, which is not considered in ADCH. The results obtained for several liquid properties indicate that the combination of CD-DFT with this population analysis leads to a good description of the charge distributions in force fields used in molecular simulations.
Pore-scale study of three-dimensional three-phase dynamic behaviors and displacement processes in porous media
Authors: Sha Xin , Chen Li , Zhang Chuangde , Wei Hangkai , Tao Wen-Quan
Published: October 2024

Carbon dioxide geological sequestration is a key method to alleviate global warming and enhance oil recovery, where the three-phase displacement processes of oil, water, and carbon dioxide gas in porous media are frequently encountered. In this study, a three-phase three-dimensional lattice Boltzmann method coupled with special wettability and outlet boundary schemes is adopted to simulate the three-phase displacement processes in porous media. The method is validated by the contact angles on a curved surface and droplet flowing through the outlet boundary. With this method, the influences of capillary number, wettability, and local large pores on three-phase flow are investigated. In particular, different dynamic behaviors of fluids are observed at the pore scale, such as bypass-double displacement, stop-wait displacement, burst displacement, snap-off trapping, and corner flow. Further, Euler number and oil saturation are calculated to quantitatively characterize the fluidic morphology and displacement efficiency under different conditions. For all three phases, the Euler number of low capillary number, strong water-wet, and structures with large and medium pores is relatively low, indicating that the morphology of fluids is more connective. For enhancing oil recovery efficiency, high capillary number and strong water-wet structures are beneficial.
Experimental study on spraying mechanisms of the gas–liquid internal flow in an air-assisted nozzle
Authors: Duan KaiQiang , Wu Haifeng , Hao Yahui , Chai Xiaofei , Wang Ruixiang
Published: October 2024

Air-assisted nozzles are widely used in many industrial fields. For example, in artificial snowmaking systems, air-assisted nozzles can provide a key promoting role for the nucleation and crystallization of snow. To reveal how spray behavior depends on the internal flow patterns of air-assisted nozzles, we designed an experimental platform to observe the two-phase flow inside the nozzle. The results show that the internal flow pattern of the nozzle exhibits an annular flow pattern, forming a continuous hollow conical spray. As the gas–liquid pressure ratio (GLRP) increases, the interfacial disturbance waves gradually disappear at the gas–liquid interface of the internal flow, indicating a transition from a more turbulent to a more stable flow regime. As the gas core expands, the liquid film thickness gradually decreases, promoting finer atomization and a more uniform droplet distribution. This transition from a disturbed wave pattern to a stable annular flow enhances the uniformity of the droplet distribution and the stability of the spray. When GLRP increases from 20% to 67%, the uniformity of droplet distribution improves by 17%, and the stability is enhanced by 60%. Additionally, this study examines the link between internal flow patterns and atomization, providing a dimensionless formula that correlates nozzle flow dynamics with spray quality based on experimental and simulation data. This contributes valuable insights for optimizing air-assisted nozzle design for superior spray performance.
Path-filtering in path-integral simulations of open quantum systems using GFlowNets
Authors: Lackman-Mincoff Jeremy , Jain Moksh , Malkin Nikolay , Bengio Yoshua , Simine Lena
Published: October 2024

An important class of methods for modeling dynamics in open quantum systems is based on the well-known influence functional (IF) approach to solving path-integral equations of motion. Within this paradigm, path-filtering schemes based on the removal of IF elements that fall below a certain threshold aim to reduce the effort needed to calculate and store the influence functional, making very challenging simulations possible. A filtering protocol of this type is considered acceptable as long as the simulation remains mathematically stable. This, however, does not guarantee that the approximated dynamics preserve the physics of the simulated process. In this paper, we explore the possibility of training Generative Flow Networks (GFlowNets) to produce filtering protocols while optimizing for mathematical stability and for physical accuracy. Trained using the trajectory balance objective, the model produces sets of paths to be added to a truncated initial set; it is rewarded if the combined set of paths gives rise to solutions in which the trace of the density matrix is conserved, the populations remain real, and the dynamics approach the exact reference. Using a simple two-level system coupled to a dissipative reservoir, we perform proof-of-concept simulations and demonstrate the elegant and surprising filtering solutions proposed by the GFlowNet.
On-demand performance optimization of AlGaN/GaN high electron mobility transistors using stoichiometric variation of dielectric alloy AlxTayO
Authors: Surapaneni Sreenadh , Ganguly Swaroop , Saha Dipankar
Published: October 2024

The current research investigates the potential advantages of optimally combining wide bandgap Al2O3 with high dielectric constant (high-κ) Ta2O5 for gate dielectric applications. Various compositions of 10 nm AlxTayO oxide films are grown on the Al0.3Ga0.7N/GaN heterostructure by co-sputtering Al and Ta metals, followed by thermal oxidation at 500 °C. The average root-mean-square roughness of the grown oxide films is ∼1.2–1.4 nm compared to 0.4 nm for as-deposited metal. X-ray photoelectron spectroscopy and transmission electron microscopyconfirm the formation and thickness of the grown oxide films. The bandgap (Eg) of the oxide films calculated from O1s electron energy loss spectra show a linear increase from 4.85 eV for pure Ta2O5 to 6.4 eV for pure Al2O3. The dielectric constant (εox) calculated from capacitance–voltage (CG−VG) measurements decreases linearly from 25.7 for Ta2O5 to 7.9 for Al2O3. The interface trap density (Dit) is estimated from the frequency dispersion of capacitance–voltage (CG−VG) characteristics. The DC and radio frequency (RF) characteristics of AlxTayO/Al0.3Ga0.7N/GaN high electron mobility transistor (HEMT) devices are measured and compared with the Schottky HEMT devices (without any gate oxide). Compared to Schottky HEMT devices, AlxTayO/Al0.3Ga0.7N/GaN HEMT devices show superior DC characteristics, which helps us achieve maximum RF output power. Furthermore, the OFF-state measurements show that the AlxTayO/Al0.3Ga0.7N/GaN HEMT devices can sustain higher source-to-drain voltages, from a minimum of 88 V on pure Ta2O5 metal-oxide-semiconductor (MOS)-HEMTs to a maximum of 138 V on pure Al2O3 MOS-HEMTs before the dielectric breakdown happens, compared to a 57 V breakdown voltage on Schottky HEMT devices. An oxide variation of AlxTayO, with Al composition ratio of 0.34, shows an exceptional ION/IOFF ratio of 4 × 1011, a gate leakage current of 8 × 10−12 A/mm, a near-ideal subthreshold slope of 63.8 mV/dec, and the unity current gain frequency (fT) of 25.6 GHz.
Uncertainty quantification on small angle x-ray scattering measurement using Bayesian deep learning
Authors: Yang Hairui , Wu Zhaolong , Zhang Kezhong , Wang Dawei , Yu Hong
Published: October 2024

Small angle x-ray scattering (SAXS) is a widely recognized solution for measuring complex nanostructures. With the increasing demand for accurately assessing structural characteristics and optimizing manufacturing processes, uncertainty quantification in SAXS inverse problems has become a critical issue. However, traditional methods face challenges such as slow computation speed and inaccurate estimation of multidimensional parameters. To overcome these issues, we propose an uncertainty quantification approach suitable for SAXS measurement that approximates the posterior using Bayesian deep learning. The effectiveness and reliability of our method are illustrated by assessing structural parameters of synthetic 2D Si grating samples. The uncertainty quantification takes only about 2.3 s, thousands of times faster than the conventional Markov Chain Monte Carlo (MCMC) methods. Also, our method has superior repeatability for parameter measurement compared to the MCMC approaches. It provides the potential of efficient and reliable SAXS measurement in increasingly intricate semiconductor manufacturing.
Propensity of hydroxide and hydronium ions for the air–water and graphene–water interfaces from ab initio and force field simulations
Authors: Scalfi Laura , Lehmann Louis , dos Santos Alexandre P. , Becker Maximilian R. , Netz Roland R.
Published: October 2024

Understanding acids and bases at interfaces is relevant for a range of applications from environmental chemistry to energy storage. We present combined ab initio and force-field molecular dynamics simulations of hydrochloric acid and sodium hydroxide highly concentrated electrolytes at the interface with air and graphene. In agreement with surface tension measurements at the air–water interface, we find that HCl presents an ionic surface excess, while NaOH displays an ionic surface depletion, for both interfaces. We further show that graphene becomes less hydrophilic as the water ions concentration increases, with a transition to being hydrophobic for highly basic solutions. For HCl, we observe that hydronium adsorbs to both interfaces and orients strongly toward the water phase, due to the hydrogen bonding behavior of hydronium ions, which donate three hydrogen bonds to bulk water molecules when adsorbed at the interface. For NaOH, we observe density peaks of strongly oriented hydroxide ions at the interface with air and graphene. To extrapolate our results from concentrated electrolytes to dilute solutions, we perform single ion-pair ab initio simulations, as well as develop force-field parameters for ions and graphene that reproduce the density profiles at high concentrations. We find the behavior of hydronium ions to be rather independent of concentration. For NaOH electrolytes, the force-field simulations of dilute NaOH solutions suggest no hydroxide adsorption but some adsorption at high concentrations. For both interfaces, we predict that the surface potential is positive for HCl and close to neutral for NaOH.
Review of diver propulsion vehicle: A review
Authors: Qin Hongde , Li Zhenqi , Xu Shengyuan , Liu Xun , Cao Xiaojian
Published: October 2024

The ocean serves as a vital arena for resource exploitation, scientific inquiry, and strategic endeavors. Among the array of underwater propulsion technologies, diver propulsion vehicles (DPVs) stand out for their exceptional integration, concealability, and maneuverability. They hold a pivotal role in both marine scientific exploration and military operations beneath the waves, thus carrying significant research implications. However, the existing literature on DPVs remains limited, lacking comprehensive examinations of their design processes and parameters. This review systematically surveys and assesses the current landscape of DPV development and research. Three key facets—propeller design, performance assessment, and equipment engineering—are scrutinized and analyzed. By consolidating essential data from ongoing studies, this review offers valuable insights. Additionally, it forecasts potential directions and emerging focal points in the evolution of underwater propulsion for frogmen, drawing from current advancements. The objective is to furnish foundational data to support the design and study of frogman underwater propulsion systems, thereby advancing engineering applications in this domain.
Variational quantum imaginary time evolution for matrix product state Ansatz with tests on transcorrelated Hamiltonians
Authors: Li Hao-En , Li Xiang , Huang Jia-Cheng , Zhang Guang-Ze , Shen Zhu-Ping , Zhao Chen , Li Jun , Hu Han-Shi
Published: October 2024

The matrix product state (MPS) Ansatz offers a promising approach for finding the ground state of molecular Hamiltonians and solving quantum chemistry problems. Building on this concept, the proposed technique of quantum circuit MPS (QCMPS) enables the simulation of chemical systems using a relatively small number of qubits. In this study, we enhance the optimization performance of the QCMPS Ansatz by employing the variational quantum imaginary time evolution (VarQITE) approach. Guided by McLachlan’s variational principle, the VarQITE method provides analytical metrics and gradients, resulting in improved convergence efficiency and robustness of the QCMPS. We validate these improvements numerically through simulations of H2, H4, and LiH molecules. In addition, given that VarQITE is applicable to non-Hermitian Hamiltonians, we evaluate its effectiveness in preparing the ground state of transcorrelated Hamiltonians. This approach yields energy estimates comparable to the complete basis set (CBS) limit while using even fewer qubits. In particular, we perform simulations of the beryllium atom and LiH molecule using only three qubits, maintaining high fidelity with the CBS ground state energy of these systems. This qubit reduction is achieved through the combined advantages of both the QCMPS Ansatz and transcorrelation. Our findings demonstrate the potential practicality of this quantum chemistry algorithm on near-term quantum devices.
Influence of phase stability on postshock mechanical properties and microstructure evolution in Ti-17 alloy
Authors: Li Zheng , Ren Yu , Zhang Ziyue , Nie Zhihua , Ning Xianjin , Tan Chengwen , Chen Pengwan
Published: October 2024

There has been a growing surge of interest in examining the shock response of titanium alloys, owing to their considerable potential for military applications. The present study aims to reveal the influence of phase stability on the shock-induced mechanical response and substructure evolution of a metastable β titanium alloy, namely, Ti-17. This investigation included extensive work, such as plate impact tests, quasi-static reloading compression tests, and electron microscope analyses. The microstructural evaluations following the shock-wave loading unveil planar slip as the prevailing deformation mechanism in Ti-17 with a bimodal microstructure with stable α and β phases. However, when the shock stress exceeds 10 GPa, the activation of {101¯1}α nano-sized twins was observed, leading to improved reloading ductility. This implies a novel strategy to achieve excellent strength-plasticity compatibility in titanium alloys through appropriate shock-wave loading. Conversely, in Ti-17 with an equiaxed β microstructure, the metastability of the β phase leads to the activation of shock-induced α″ martensite, shock-induced ω, and planar slip. Two distinct forms of interaction involving the α″ laths, i.e., shear and truncation, were also observed. Phase stability greatly influences substructure evolution, which ultimately controls the reloading mechanical properties of the postshock Ti-17 alloy.
Classification of solid and liquid structures using a deep neural network unveils origin of dynamical heterogeneities in supercooled liquids
Authors: Liu Min , Oyama Norihiro , Kawasaki Takeshi , Mizuno Hideyuki
Published: October 2024

As the temperature decreases, the dynamics of supercooled liquids significantly slow down and become increasingly heterogeneous in space. Many previous studies have found that static structures also become heterogeneous and are spatially correlated with the dynamical heterogeneity. However, there are still debates on whether the dynamical heterogeneity is controlled by the structures, and which structural order parameters should be used to describe the structural heterogeneities (if exist) in amorphous systems. The appropriate order parameter depends on the specific details of the system and needs to be determined for each system. To address this difficulty, here, we use a machine-learning-based method that was trained solely by the static structures. This method combines convolutional neural networks and gradient-weighted class activation mapping, providing interpretable characteristic structures, which can quantify the degrees of liquid-like and solid-like structures in every local part of the system. We apply this method to a canonical glass-forming system and demonstrate that particles in the liquid-like structures are mobile, while those in the solid-like structures are immobile. The present work develops a novel approach to accurately characterize amorphous structures, which will be particularly useful for systems where appropriate structural order parameters have not yet been identified.
Acoustics of wet porous media with evaporation/condensation
Authors: Boutin Claude , Venegas Rodolfo
Published: October 2024

This paper investigates acoustic wave propagation in wet rigid-frame porous media accounting for evaporation and condensation. At equilibrium, the solid walls are covered by a thin water film, and water vapor in the air is at its temperature-dependent saturation pressure. Small acoustic perturbations cause water to vaporize or condense, which together with the reversibility of the phase change, lead to a linear problem where the usual local poro-acoustics physics is enriched with the (i) Clapeyron relation linking liquid-wall temperature, vapor pressure, and latent heat of vaporization, (ii) latent heat transfer in the solid frame, (iii) diffusion equation for water vapor in air, and (iv) water vapor's equation of state. The equilibrium temperature highly influences the vapor concentration and the physical parameters of saturated moist air. Using the two-scale asymptotic homogenization method, it is shown that the dynamic permeability is determined similarly to classical porous media, while the effective compressibility is modified by evaporation/condensation and the equilibrium temperature. This modification is influenced by vapor mass and heat flows associated with phase changes through a local fully coupled heat transfer and water vapor diffusion problem, with specific boundary conditions at the gas–water interface. The analysis identifies dimensionless parameters and characteristic frequencies defining the upscaled model's features. Depending on equilibrium temperature, the theory qualitatively and quantitatively determines the characteristics of acoustic waves propagating through the media. The results are illustrated and discussed with analytically developed models.
Self-diffusion of liquid deuterium hydride and liquid tritium
Authors: Prisk T. R. , Hanna S. , Azuah R. T.
Published: October 2024

We present a quasi-elastic neutron scattering study of liquid deuterium hydride carried out using the Disk Chopper Spectrometer at the National Institute of Standards and Technology. Under saturated vapor pressure, the self-diffusion constant of deuterium hydride obeys an Arrhenius law D=D0exp−EA/kBT, where the prefactor D0 is given by D0=9.5±1.2Å2/ps and the activation energy is given by EA = 58 ± 2 K. We apply the quantum law of corresponding states to the known diffusion constants of the hydrogen isotopologues. From this application, we estimate that D0≈9.1Å2/ps and EA ≈ 75 K in liquid tritium. Young’s theory of quantum-mechanical effects in van der Waals fluids [Young, Phys. Rev. A 23, 1498 (1981)] is shown to apply to the diffusion constants of the liquid hydrogens. Our results underscore the importance of nuclear quantum effects in shaping the properties and behavior of the hydrogen isotopologues.
Effects of lattice instability on the thermoelectric behavior of kagome metal ScV6Sn6
Authors: Kuo C. N. , Huang R. Y. , Tian W. S. , Hong C. K. , Ou Y. R. , Kuo Y. K. , Lue C. S.
Published: October 2024

Kagome metal ScV6Sn6 has been a subject of interest due to the emergence of a first-order structural phase transition with intriguing charge density wave behavior below the transition temperature Tc ∼ 92 K. To explore the thermoelectric properties and provide experimental insights into the nature of the phase transition, we have carried out a combined study by means of the electrical resistivity, Seebeck coefficient, and thermal conductivity measurements on single crystalline ScV6Sn6. Pronounced features near Tc have been characterized by all measured physical quantities. In particular, the Seebeck coefficient exhibits a marked reduction as lowering temperature across Tc, attributed to an imbalance of the contribution from different type of carriers induced by the structural phase transition. From the examination of the electronic and lattice thermal conductivities, we obtained a confirmation that the observed enhancement at Tc is essentially caused by the change of the lattice thermal conductivity, demonstrating the primary importance of lattice distortions for the heat transport of ScV6Sn6. In addition, the lattice thermal conductivity above Tc was found to increase monotonically with temperature. We associated the peculiar phenomenon with lattice fluctuations, highlighting the essence of structural instability in the kagome lattice ScV6Sn6. These results add to the knowledge about the thermal transport properties in kagome materials with a hexagonal HfFe6Ge6-type structure.
The influence of salt concentration on the dissolution of microbubbles in bulk aqueous electrolyte solutions
Authors: Yakovlev Egor V. , Kryuchkov Nikita P. , Gorbunov Evgeny A. , Zotov Arsen K. , Ovcharov Pavel V. , Yurchenko Stanislav O.
Published: October 2024

We study microbubbles (MBs) in aqueous electrolyte solutions and show that increasing the salt concentration slows down the kinetics of MB dissolution. We modified the Epstein–Plesset theory and experimented with NaCl aqueous solutions to estimate the MB effective surface charge and to compare it with predictions from the modified Poisson–Boltzmann theory. Our results reveal a mechanism responsible for the change in the dissolution of MBs in aqueous electrolyte solutions, with implications for emerging fields ranging from physics of solutions to soft and biological matter.
Two-dimensional boundary layer receptivity to finite periodic disturbances
Authors: Li Peifan , Cao Zhen , Li Dong , An Bo , Chen Shusheng , Deng Xiaogang
Published: October 2024

Receptivity is the focus and frontier of the research on boundary layer transition and flow drag reduction, but the temporal and spatial evolution of Tollmien–Schlichting waves (T-S waves) is not yet fully investigated, limiting the development of highly efficient laminar flow control techniques. In the present study, the local receptivity problem of the laminar boundary layer on a zero-pressure-gradient flat plate is investigated by using the direct numerical simulation, considering both the temporal and spatial evolution characteristics of the T-S waves. External disturbances at fixed frequencies are introduced in the form of velocity pulsations with different periods to excite T-S waves. The temporal and spatial evolution characteristics of the T-S waves excited by different forms and periods of disturbances are studied. It is found that the amplitude, frequency, and wave velocity of the T-S wave induced by the external multi-period disturbances are different from those induced by the constant disturbances. These conclusions are the same as those of T-S wave induced by wall inhalation. After a further investigation on this particular phenomenon, the influence mechanism of external disturbances on the receptivity process is revealed. This new research finding enriches the instability theory and provides a reference for more efficient applications on active laminar flow control technologies.
Comparison of hybrid deep learning models for estimation of the time-dependent scour depth downstream of river training structures
Authors: Azma Aliasghar , Liu Yakun , Eftekhari Mobin , Zhang Di
Published: October 2024

Submerged weirs, mainly positioned downstream of bridges, play a key role in safeguarding against floods and long-term scour damage. However, the structural stability of these structures could be threatened by local scour holes. This study evaluates five deep learning algorithms—Deep Neural Networks, Convolutional Neural Networks (CNNs), Convolutional Extreme Gradient Boosting (CXGB), convolutional extremely randomized trees regression, and Self-Attention-based Convolutional Neural Network (SA-CNN) in predicting the evolution of scour depth. Using Hyperband and Bayesian optimization, the models were fine-tuned for maximum accuracy. Additionally, this study investigates the impact of two data splitting methods, including random pointwise sampling and case-wise sampling on model performance. Results indicate that the hybrid CXGB and the SA-CNN models outperform other models in terms of accuracy of the estimation of the time-dependent scour depth with R2 = 0.997 in pointwise and R2 = 0.878 in case-wise split strategies, respectively. This not only demonstrates the effectiveness of these sophisticated algorithms in time-dependent scour estimation but also clarifies the effects of various data sampling techniques on model performance. Finally, the contribution of features in provided estimations is discussed utilizing SHapley Additive exPlanations values. Results indicated that the time (T) and the ratio of the flow velocity to critical velocity U0/Uc had the greatest effect on the model outputs, while side slopes indicated a negligible effect on model output compatible with the physics of the problem.
Performance study of explosively formed projectile using CoCrFeNi high-entropy alloy as a liner
Authors: Li Rong-Xin , Chen Jia-Lin , Wang Rui-Qi , Song Jia-Xing , Huang Jun-Yi , Zhang A.-Zhen , Wu Jia-Xiang , Li Yu-Chun
Published: October 2024

Based on mechanical tensile experiments on the CoCrFeNi high-entropy alloy (HEA), this study explores the forming patterns of the eccentrically shaped sub-hemispherical lined explosively formed projectile (EFP) made of the HEA material. The CoCrFeNi HEA material is initially prepared, and mechanical tensile tests are conducted at various temperatures and strain rates. The Johnson–Cook (J–C) constitutive equation for this material is derived by fitting the experimental data. Scanning electron microscopy and the energy dispersive spectrometer characterize the fracture surface of the tensile specimens, providing insights into the mechanical ductility and fracture mechanism of CoCrFeNi HEA. The EFP forming process under various charge configurations is simulated using AUTODYN software, leading to the identification of the optimal charge configuration. In addition, the damage performance is evaluated. This study provides a theoretical basis for applying HEA materials in the field of shaped charges and offers new ideas and methods for designing more efficient shaped charge warheads.
Effect of wettability and surface roughness on flow and heat transfer characteristics in nanochannels
Authors: Miao Shanshan , Xia Guodong , Zhou Wenbin , Shang Huiqing
Published: October 2024

The flow and heat transfer processes of liquid argon within nanochannels with random roughness are investigated using the molecular dynamics method. This study explores the effects of surface roughness and wettability on flow and heat transfer performance. The results indicate that both surface roughness and wettability significantly influence temperature jumps, velocity slip, flow resistance, and temperature distribution. Specifically, hydrophilic surfaces can reduce temperature jumps and velocity slip due to their enhanced ability to adsorb liquid atoms, which effectively improves heat transfer while simultaneously increasing flow resistance. The fractal dimension D characterizes the surface roughness, which decreases as D increases. Additionally, both the Nusselt number and drag coefficient decrease with increasing D. In this study, we investigate cases where D ranges from 2.5 to 2.9, with D = 2.5 representing the highest roughness, and the smooth channel corresponding to the lowest roughness. For hydrophilic nanochannels at D = 2.5, the Nusselt number and drag coefficient increased by factor of 2.2 times and 5.2 times compared to smooth channels, respectively. For hydrophobic nanochannels at D = 2.5, the Nusselt number and drag coefficient increased by a factor of 4.5 times and 29.1 times compared to smooth surface channels, respectively. Considering both flow and heat transfer performances, the best comprehensive performance is achieved with D = 2.8 for channels with hydrophilic surfaces and D = 2.6 for channels with hydrophobic surfaces. This work systematically investigates the coupled effects of random roughness and wettability on the flow and heat transfer characteristics in nanochannels, providing new theoretical insights for optimizing nanochannel design.