bluuebunny/crossref_metadata_2025 huggingface dataset:
Speed Control of Induction Motor using Digital Signal Processor TMS320F28027F
Authors: Awaar Vinay Kumar , M.N Sandhya Rani , Naragani Pravardh , Talluri Sasidhar , Polisetty Samanvita , Vakkalanka Satya Sreyas , Al-Jawahry Hassan Mohmmed
Published: June 2023

Single-phase induction motors are widely used today. A single-phase induction motor is operated using a single-phase inverter. The Single-phase inverter consists of four MOSFETs, two for the high side and two for the low side. The Single-phase induction motors are a constant speed motor. As a corollary, the speed control of the Single-Phase Induction motor becomes a very important necessity. Speed control of the Single-Phase Induction motor can be done in many ways. The method followed in this paper is voltage control/ (V/F Control). By controlling the duty cycle of the MOSFETs, we can control the output of the inverter and there by control the speed of the Single-Phase Induction motor. The inverter has been interfaced with MATLAB, which generates pulses and sends them to the Digital Signal processor. Texas Instrument’s low-cost Piccolo F2802x MCUs are ideal for a variety of applications, such as washing machines, compressors, pumps, fans, electric bicycles, tools, treadmills, compact drives, sewing and textile machines, lifts and hobby motors. This paper focuses on closed loop control of single-phase induction motor using this Micro Controller, F2802x Digital Signal Processor using feedback obtained through a Hall Sensor.
Efficient Feature Extraction for Recognition of Human Emotions through Facial Expressions Using Image Processing Algorithms
Authors: M.K. Linga Murthy , Modepalli Divyanjali , Shaik Maibu Basha , Busi Madhuri , C. Venkataiah , Y. Mallikarjuna Rao , Alkhayyat Ahmed , Rawat Divya
Published: June 2023

Face emotion recognition is a challenging problem in computer vision that has been extensively studied in recent years. The project investigates the performance of Local Binary Pattern (LBP), Histogram of Oriented Gradients (HOG), K- Nearest Neighbour (KNN), and Support Vector Machine (SVM) for face emotion recognition. The aim of this study is to evaluate the performance of different combinations of these techniques and to identify the most effective approach for this task. To achieve this, we first collected a dataset of facial expressions that includes seven basic emotions such as happy, sad, angry, surprise, Neutral, fear, and disgust. We then extract LBP and HOG features from the facial images and then KNN and SVM classifiers to classify the emotions. We experimented with various combinations of LBP, HOG, KNN, and SVM and evaluated the performance of each approach using metrics such as accuracy, precision, recall, and F1 score. This study demonstrates the effectiveness of combining LBP and HOG features with KNN and SVM for face emotion recognition. Our results suggest that SVM is the most effective model for this task, when it is combined with HOG features and can further improve the system39;s performance. The model can be implemented using MATLAB and GUI Interface. These findings have important implications for the development of accurate and reliable face emotion recognition systems for various applications, including human-computer interaction, gaming, and healthcare.
A biased random-key genetic algorithm for the chordal completion problem
Authors: Silva Samuel E. , Ribeiro Celso C. , dos Santos Souza Uéverton
Published: June 2023

A graph is chordal if all its cycles of length greater than or equal to four contain a chord,i.e., an edge connecting two nonconsecutive vertices of the cycle. Given a graphG= (V, E), the chordal completion problem consists in finding the minimum set of edges to be added toGto obtain a chordal graph. It has applications in sparse linear systems, database management and computer vision programming. In this article, we developed a biased random-key genetic algorithm (BRKGA) for solving the chordal completion problem, based on the strategy of manipulating permutations that represent perfect elimination orderings of triangulations. Computational results show that the proposed heuristic improve the results of the constructive heuristics fill-in and min-degree. We also developed a strategy for injecting externally constructed feasible solutions coded as random keys into the initial population of the BRKGA that significantly improves the solutions obtained and may benefit other implementations of biased random-key genetic algorithms.
Reduced cutout for reverse oblique intertrochanteric hip fractures treated with trochanteric fixation advanced (TFN-A) nail compared to the short gamma-3 nail
Authors: Elbaz Etay , Morgan Samuel , Factor Shai , Shaked Or , Graif Nadav , Ben-Tov Tomer , Khoury Amal , Warschawski Yaniv
Published: June 2023

Background: Reverse oblique fractures (AO/OTA 31-A3) account for 5–23% of all intertrochanteric fractures and are challenging to manage. The Gamma 3-Proximal Femoral Nail (GPFN) and the Trochanteric Fixation Nail Advanced (TFNA) are two common cephalomedullary systems used to treat this fracture. No study has reported on outcomes with the TFN-A for reverse oblique fractures. This study aimed to compare outcomes and complication rates in patients with reverse oblique fractures, treated with either TFNA or GPFN. Patients and methods: A total of 203 patients with reverse oblique fractures (137 in the GPFN group and 66 in the TFNA group), were treated in our institution between June 2010 and May 2019. Data was collected on postoperative radiological variables including screw or blade location, and tip-apex distance (TAD). Data were also collected for non-orthopaedic complication rates and orthopaedic complications. A sub-group analysis was additionally performed for different nail lengths. Results: We found no significant difference in the overall rate of complications and revisions between the two groups. Patients treated with the 235 mm TFN-A nail sustained lower rates of cutout, compared to 180 mm GPFN (GPFN: 6% TFN-A: 0%, p = 0.043). The frequency of revision surgeries and malunions/non-unions did not differ significantly between the two groups and additionally showed no difference in the subgroup analysis. Conclusion: The 235 mm TFN-A was associated with lower rates of cut-out compared to the short GPFN for reverse oblique intertrochanteric fractures. Future well-designed prospective studies are warranted to investigate the role of the TFN-A in improving outcomes for such fractures.
Hsa_Circ_0104206 is An Oncogenic circRNA in Colon Cancer by Targeting
Mir-188–3p/CCNA2 Axis
Authors: Li Zhong , Li Quanfu , Chen Zhuo
Published: June 2023

The identification of specific biomarkers is essential to improve cancer therapy,
and circular RNAs (circRNAs) have great potency to be biomarkers. We harbor the
goal to unveil the role of circ_0104206 in colon cancer (CC). The relative
expressions of circ_0104206, miR-188–3p and CCNA2 in different groups
were studied using real-time quantitative PCR (qPCR) or western blotting. The
proliferative and migratory capacity of cancer cells were monitored via CCK-8,
colony formation and Transwell assays. The transplanted tumor models were
generated to analyze circ_0104206’s role in vivo. The putative
relationship between miR-188–3p and circ_0104206 or CCNA2 by
bioinformatics tools was testified through dual-luciferase or RIP assay. The
abnormal elevation of circ_0104206 expression was observed in CC. Circ_0104206
silencing repressed CC cell proliferative and migratory behaviors, and also
decelerated tumor development in animal models. MiR-188–3p was directly
targeted by circ_0104206, and its inhibitor had the ability to reverse the
anticancer effects of circ_0104206 silencing on CC cells. CCNA2 was a target
downstream of circ_0104206/miR-188–3p network. Moreover, the
repressive effects of CCNA2 absence on cell proliferation and migration were
attenuated by miR-188–3p inhibitor. In conclusion, Circ_0104206 plays
oncogenic roles in CC via the implication of miR-188–3p/CCNA2
network, which further discloses CC pathogenesis and supplies potential markers
for CC.
Mehr als nur verschiedene Sprachen – Interkulturelles
Notfallmanagement
Authors: Peters Tim , Langner Michael
Published: June 2023

Im folgenden Artikel geht es darum, mit Menschen mit Migrationsgeschichte in
Notfällen richtig zu kommunizieren. Dabei geht es nicht nur um
sprachliche Herausforderungen und ggf. um das Organisieren eines Dolmetschers,
sondern auch darum, eine ethische Dimension mitzudenken und kulturelle
Missverständnisse in der Kommunikation zu vermeiden.
Engaging Patients and Other Stakeholders in “Designing for Dissemination” of Record Linkage Methods and Tools
Authors: Reno Jenna E. , Ong Toan C. , Voong Chan , Morse Brad , Ytell Kate , Koren Ramona , Kwan Bethany M.
Published: June 2023

Background Novel record linkage (RL) methods have the potential to enhance clinical informatics by integrating patient data from multiple sources—including electronic health records, insurance claims, and digital health devices—to inform patient-centered care. Engaging patients and other stakeholders in the use of RL methods in patient-centered outcomes research (PCOR) is a key step in ensuring RL methods are viewed as acceptable, appropriate, and useful. The University of Colorado Record Linkage (CURL) platform empowers the use of RL in PCOR.

Objectives This study aimed to describe the process of engaging patients and other stakeholders in the design of an RL dissemination package to support the use of RL methods in PCOR.

Methods Customer discovery, value proposition design, and user experience methods were used to iteratively develop an RL dissemination package that includes animated explainer videos for patients and an RL research planning workbook for researchers. Patients and other stakeholders (researchers, data managers, and regulatory officials) were engaged in the RL dissemination package design.

Results Patient partners emphasized the importance of conveying how RL methods may benefit patients and the rules researchers must follow to protect the privacy and security of patient data. Other stakeholders described accuracy, flexibility, efficiency, and data security compared with other available RL solutions. Dissemination package communication products reflect the value propositions identified by key stakeholders. As prioritized by patients, the animated explainer videos emphasize the data privacy and security processes and procedures employed when performing research using RL. The RL workbook addresses researchers' and data managers' needs to iteratively design RL projects and provides accompanying resources to alleviate leadership and regulatory officials' concerns about data regulation compliance.

Conclusion Dissemination products to promote adoption and use of CURL include materials to facilitate patient engagement in RL research and investigator step-by-step decision-making materials about the integration of RL methods in PCOR.
Investment effect of regional trade agreements: an analysis from the perspective of heterogeneous agreement provisions
Authors: Yue Wen , Lin Qingxia , Xu Siyu
Published: June 2023

Global regional trade agreements (RTAs) are experiencing unprecedented rapid development in terms of number and content of provisions, and China’s RTAs are no exception. With the increase in the depth of RTA provisions, as an important form of economic and trade relations between countries, investment is bound to be affected. Taking the RTAs signed by China as the research object and using the bilateral foreign direct investment (FDI) data provided by the International Monetary Fund CDIS database and the relevant data from the World Bank RTA text depth database, this paper constructs various indexes to measure the depth of RTA provisions and analyzes the effects of changes in the depth of RTA provisions on inward FDI stocks to China. The study finds that the improvement of all four depth indexes, namely, total depth, core depth, depth of WTO+ provisions, and depth of WTO-X provisions, significantly promotes China’s inward FDI stocks. This conclusion still holds after a series of endogenous problem analysis and robustness tests. Further analysis shows that the improvement of the depth of RTA provisions has a relatively greater effect on FDI stocks from developing countries and countries along the “Belt and Road”. At the same time, there exists significant heterogeneity in the effects of different RTA provisions on the FDI stocks. The insights that we obtain in this paper enable us to provide policy recommendations for the construction of China’s global high-standard free trade agreement (FTA) network.
Sociocultural adaptation and job satisfaction as mediators between cultural competence and intention to stay among Vietnamese workers in Taiwan
Authors: Tsang Seng-Su , Nguyen Thi Vinh Tran
Published: June 2023

This study employs a moderated mediation model to investigate the role of sociocultural adaptation and job satisfaction in the relationship between cultural competence and intention to stay. It also considers the moderating function of local language proficiency and length of residence. A survey was conducted among Vietnamese migrant workers employed in Taiwan’s manufacturing industry under the labour export programme. This resulted in a valid dataset of 636 respondents, which was used to test the proposed hypotheses. The findings demonstrated that sociocultural adaptation and job satisfaction fully mediated the relationship between cultural competence and workers’ intention to stay. Moreover, local language proficiency and length of residence were found to substantially strengthen the positive relationship between cultural competence and sociocultural adaptation, but not to moderate the association between cultural competence and job satisfaction. Theoretically, the study contributes to the literature on psychological and behavioural management by examining how migrant workers’ job satisfaction and sociocultural adaptation are related to the association between cultural competence and intention to stay. Practically, the study addresses current concerns regarding the rate of job retention among migrant workers participating in labour export programmes. Its findings provide policymakers and employers with additional evidence to improve and effectively maintain their foreign labour force. It is recommended that both sending and receiving governments implement appropriate and effective management policies to manage the low-skilled foreign labour force.
Effectiveness of phase synchronization in chaotic food chain model with refugia and Allee effects during seasonal fluctuations
Authors: Dwivedi Shubhangi , Kumari Nitu
Published: June 2023

Seasonal effects powerfully shape the population dynamics with periodic climate changes because species naturally adjust their dynamics with seasonal variations. In response to these effects, sometimes population dynamics exhibit synchrony or generate chaos. However, synchronized dynamics enhance species’ persistence in naturally unstable environments; thus, it is imperative to identify parameters that alter the dynamics of an ecosystem and bring it into synchrony. This study examines how ecological parameters enable species to adapt their dynamics to seasonal changes and achieve phase synchrony within ecosystems. For this, we incorporate seasonal effects as a periodic sinusoidal function into a tri-trophic food chain system where two crucial bio-controlling parameters, Allee and refugia effects, are already present. First, it is shown that the seasonal effects disrupt the limit cycle and bring chaos to the system. Further, we perform rigorous mathematical analysis to perform the dynamical and analytical properties of the nonautonomous version of the system. These properties include sensitive dependence on initial condition (SDIC), sensitivity analysis, bifurcation results, the positivity and boundedness of the solution, permanence, ultimate boundedness, and extinction scenarios of species. The SDIC characterizes the presence of chaotic oscillations in the system. Sensitivity analysis determines the parameters that significantly affect the outcome of numerical simulations. The bifurcation study concerning seasonal parameters shows a higher dependency of species on the frequency of seasonal changes than the severity of the season. The bifurcation study also examines the bio-controlling parameters and reveals various dynamic states within the system, such as fold, transcritical branch points, and Hopf points. Moreover, the mathematical analysis of our seasonally perturbed system reveals the periodic coexistence of all species and a globally attractive solution under certain parametric constraints. Finally, we examine the role of essential parameters that contribute to phase synchrony. For this, we numerically investigate the defining role of the coupling dimension coefficient, bio-controlling parameters, and other parameters associated with seasonality. This study infers that species can tune their dynamics to seasonal effects with low seasonal frequency, whereas the species’ tolerance for the severity of seasonal effects is relatively high. The research also sheds light on the correlation between the degree of phase synchrony, prey biomass levels, and the severity of seasonal forcing. This study offers valuable insights into the dynamics of ecosystems affected by seasonal perturbations, with implications for conservation and management strategies.
Zealous cooperation does not always promote cooperation in public goods games
Authors: Wang Chaoqian , Sun Chengbin
Published: June 2023

There is a conventional belief that prosocial behaviors cannot arise through selfish human nature, because defection always exploits cooperation to achieve a higher payoff at an individual level. Unyieldingly, some people hope to move society to cooperation through their zealous cooperation, regardless of payoffs. From the perspective of spatial evolutionary games, however, such zealous behavior is unnecessary because cooperation can emerge from selfish human nature by aggregating in evolution. Yet, to what extent can zealous cooperation induce others to cooperate? We assume a fraction of zealous agents in spatial public goods games who always cooperate. The results show that a moderate proportion of these zealous cooperators can diminish the cooperation level in the system, and cooperation is only promoted when zealots are many. Regarding spatial behaviors, the areas of zealous cooperation in a medium density can prevent evolutionary cooperation from passing through and aggregating. The phenomenon of zealous cooperation impeding cooperation becomes more pronounced when agents become less random and more selfish. This is because dotted zealous cooperation provides significant payoffs to neighboring defection, making them more solid in fitness. In this way, we also find that when zealous cooperators have low productivity, the neighbors receive fewer benefits by exploitation, thus allowing cooperation to spread. We also study replicator dynamics in unstructured populations where zealous cooperation always promotes cooperation, agreeing that zealous cooperation hindering cooperation is a spatial effect.
MDiGest: A Python package for describing allostery from molecular dynamics simulations
Authors: Maschietto Federica , Allen Brandon , Kyro Gregory W. , Batista Victor S.
Published: June 2023

Many biological processes are regulated by allosteric mechanisms that communicate with distant sites in the protein responsible for functionality. The binding of a small molecule at an allosteric site typically induces conformational changes that propagate through the protein along allosteric pathways regulating enzymatic activity. Elucidating those communication pathways from allosteric sites to orthosteric sites is, therefore, essential to gain insights into biochemical processes. Targeting the allosteric pathways by mutagenesis can allow the engineering of proteins with desired functions. Furthermore, binding small molecule modulators along the allosteric pathways is a viable approach to target reactions using allosteric inhibitors/activators with temporal and spatial selectivity. Methods based on network theory can elucidate protein communication networks through the analysis of pairwise correlations observed in molecular dynamics (MD) simulations using molecular descriptors that serve as proxies for allosteric information. Typically, single atomic descriptors such as α-carbon displacements are used as proxies for allosteric information. Therefore, allosteric networks are based on correlations revealed by that descriptor. Here, we introduce a Python software package that provides a comprehensive toolkit for studying allostery from MD simulations of biochemical systems. MDiGest offers the ability to describe protein dynamics by combining different approaches, such as correlations of atomic displacements or dihedral angles, as well as a novel approach based on the correlation of Kabsch–Sander electrostatic couplings. MDiGest allows for comparisons of networks and community structures that capture physical information relevant to allostery. Multiple complementary tools for studying essential dynamics include principal component analysis, root mean square fluctuation, as well as secondary structure-based analyses.
Hamiltonian neural networks with automatic symmetry detection
Authors: Dierkes Eva , Offen Christian , Ober-Blöbaum Sina , Flaßkamp Kathrin
Published: June 2023

Recently, Hamiltonian neural networks (HNNs) have been introduced to incorporate prior physical knowledge when learning the dynamical equations of Hamiltonian systems. Hereby, the symplectic system structure is preserved despite the data-driven modeling approach. However, preserving symmetries requires additional attention. In this research, we enhance HNN with a Lie algebra framework to detect and embed symmetries in the neural network. This approach allows us to simultaneously learn the symmetry group action and the total energy of the system. As illustrating examples, a pendulum on a cart and a two-body problem from astrodynamics are considered.
Pressure-induced successive phase transitions and Fano resonance engineering in lead-free piezoceramics KNbO3
Authors: Qi Wenming , Xie Cuihuan , Hushur Anwar , Kojima Seiji
Published: June 2023

We carried out detailed high-pressure Raman scattering studies on lead-free perovskite piezoceramics KNbO3 (KNO) with a smaller pressure interval so that the successive phase transition pressures are precisely determined (PO→T: 8.2 GPa; PT→C: 10.9 GPa). The pressure-quenched phase does not return to the ambient orthorhombic phase completely. In this work, the pressure-induced phase transition sequence is discussed in detail. Also, based on the pressure-dependent Raman spectra of KNO, we have discovered clear evidence of a pressure-induced Fano resonance. It reveals the role played by the Raman-active continuum and discrete energy states in the condensed matter system under high pressure and enables the high-pressure Fano resonances engineering in arbitrary geometries [q∈(−∞, 0)]. These findings highlight the opportunity for designing and tuning the wave transmission and optical switch properties of lead-free piezoceramics KNO via high pressure.
Conditional cross-map-based technique: From pairwise dynamical causality to causal network reconstruction
Authors: Yang Liufei , Lin Wei , Leng Siyang
Published: June 2023

Causality detection methods based on mutual cross mapping have been fruitfully developed and applied to data originating from nonlinear dynamical systems, where the causes and effects are non-separable. However, these pairwise methods still have shortcomings in discriminating typical network structures, including common drivers, indirect dependencies, and facing the curse of dimensionality, when they are stepping to causal network reconstruction. A few endeavors have been devoted to conquer these shortcomings. Here, we propose a novel method that could be regarded as one of these endeavors. Our method, named conditional cross-map-based technique, can eliminate third-party information and successfully detect direct dynamical causality, where the detection results can exactly be categorized into four standard normal forms by the designed criterion. To demonstrate the practical usefulness of our model-free, data-driven method, data generated from different representative models covering all kinds of network motifs and measured from real-world systems are investigated. Because correct identification of the direct causal links is essential to successful modeling, predicting, and controlling the underlying complex systems, our method does shed light on uncovering the inner working mechanisms of real-world systems only using the data experimentally obtained in a variety of disciplines.
Preparation of degenerate n-type AlxGa1−xN (0 < x ≤ 0.81) with record low resistivity by pulsed sputtering deposition
Authors: Nishikawa Yuto , Ueno Kohei , Kobayashi Atsushi , Fujioka Hiroshi
Published: June 2023

Highly conductive AlGaN alloys hold a great technological potential, wherein the degenerate n-type doping is key in reducing parasitic resistances in electronic and opto-electronic devices. Nonetheless, AlxGa1−xN elaborated in conventional methods exhibits degraded electron concentration at high Al compositions. Here, we demonstrated the growth of degenerate n-type AlxGa1−xN (0 < x ≤ 0.81) with record high electron concentrations by using the pulsed sputtering deposition (PSD) method. The fabricated samples were investigated by cathodoluminescence and Hall-effect measurements in studying the related deep-level emission and electron mobility, respectively. Our findings showed that the PSD-grown heavily Si-doped AlxGa1−xN exhibits record low resistivity values: 2.5 × 10−3 Ω cm with an electron concentration of 1.2 × 1020 cm−3 for x = 0.60 and 1.7 × 10−2 Ω cm with an electron concentration of 3.2 × 1019 cm−3 for x = 0.81. Temperature-dependent Hall-effect measurements confirmed the degenerate nature of heavily Si-doped AlxGa1−xN up to x = 0.81. These results clearly show that the PSD n-type AlGaN is quite promising for reducing parasitic resistance in AlGaN based far UVC light-emitting devices and high breakdown voltage electron devices.
Investigation of concentric-zonal color effects in polyphase ceramic samples by x-ray fluorescence analysis
Authors: Baimolda Dossan , Cechak Tomas , Kulbek Marat , Aytan Nazygul , Shyngysova Shyryn
Published: June 2023

The purpose of this study is to investigate and analyze new concentric-zonal color effects in polyphase ceramic samples, particularly in a ceramic sample obtained from coal ash in the Ekibastuz coal basin. The study aims to explore the nature and characteristics of these color bands through x-ray fluorescence analysis, and provide a qualitative and quantitative analysis of the obtained x-ray fluorescence spectra. This paper presents the results of the study of new volume-surface concentric-zonal color effects in polyphase ceramic samples. Concentric-zonal color bands on the cross-sectional surface of a ceramic cylindrical sample were investigated by using x-ray fluorescence analysis. The experimental work was carried out at the laboratory of the Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague. A comparative qualitative and quantitative analysis of the obtained x-ray fluorescence spectra was carried out.
High-directivity and compact microstrip coupler for RF power applications
Authors: Chan Cheng-Hsuan , Yu Tsung-Chi , Chang Tsun-Hsu
Published: June 2023

A microstrip coupler was designed, fabricated, and tested to monitor the power of the 500 MHz kW-level amplifier modules currently installed in an 80-kW solid-state transmitter. The proposed coupler consists of multi-section coupled lines and employs a reverse-coupling scheme, achieving a very compact structure. The dual-side configuration with good termination enables the coupler to have high directivity and wide bandwidth without using any lump components for better temperature stability. Under a low-power test, the measured coupling is 37.69 dB with high directivity from 82 to 700 MHz. The coupling is almost independent of the power at 499.65 MHz, while the directivity slightly decreases to 33.85 dB at the input power of 1 kW. The maximal insertion loss of 0.08 dB was observed at 1-kW input power. The proposed directional coupler suits many high-power applications, especially in low-frequency regimes.
Interconnected ordinal pattern complex network for characterizing the spatial coupling behavior of gas–liquid two-phase flow
Authors: Du Meng , Wei Jie , Li Meng-Yu , Gao Zhong-ke , Kurths Jürgen
Published: June 2023

The complex phase interactions of the two-phase flow are a key factor in understanding the flow pattern evolutional mechanisms, yet these complex flow behaviors have not been well understood. In this paper, we employ a series of gas–liquid two-phase flow multivariate fluctuation signals as observations and propose a novel interconnected ordinal pattern network to investigate the spatial coupling behaviors of the gas–liquid two-phase flow patterns. In addition, we use two network indices, which are the global subnetwork mutual information (I) and the global subnetwork clustering coefficient (C), to quantitatively measure the spatial coupling strength of different gas–liquid flow patterns. The gas–liquid two-phase flow pattern evolutionary behaviors are further characterized by calculating the two proposed coupling indices under different flow conditions. The proposed interconnected ordinal pattern network provides a novel tool for a deeper understanding of the evolutional mechanisms of the multi-phase flow system, and it can also be used to investigate the coupling behaviors of other complex systems with multiple observations.
Paradoxical nature of negative mobility in the weak dissipation regime
Authors: Wiśniewski Mateusz , Spiechowicz Jakub
Published: June 2023

We reinvestigate a paradigmatic model of nonequilibrium statistical physics consisting of an inertial Brownian particle in a symmetric periodic potential subjected to both a time-periodic force and a static bias. In doing so, we focus on the negative mobility phenomenon in which the average velocity of the particle is opposite to the constant force acting on it. Surprisingly, we find that in the weak dissipation regime, thermal fluctuations induce negative mobility much more frequently than it happens if dissipation is stronger. In particular, for the very first time, we report a parameter set in which thermal noise causes this effect in the nonlinear response regime. Moreover, we show that the coexistence of deterministic negative mobility and chaos is routinely encountered when approaching the overdamped limit in which chaos does not emerge rather than near the Hamiltonian regime of which chaos is one of the hallmarks. On the other hand, at non-zero temperature, the negative mobility in the weak dissipation regime is typically affected by weak ergodicity breaking. Our findings can be corroborated experimentally in a multitude of physical realizations, including, e.g., Josephson junctions and cold atoms dwelling in optical lattices.
Cascade-enhanced transport efficiency of biochemical systems
Authors: Cao Zhiyu , Bao Ruicheng , Hou Zhonghuai
Published: June 2023

Recent developments in nonequilibrium thermodynamics, known as thermodynamic uncertainty relations, limit the system’s accuracy by the amount of free-energy consumption. A transport efficiency, which can be used to characterize the capacity to control the fluctuation by means of energy cost, is a direct result of the thermodynamic uncertainty relation. According to our previous research, biochemical systems consume much lower energy cost by noise-induced oscillations to keep almost equal efficiency to maintain precise processes than that by normal oscillations. Here, we demonstrate that the performance of noise-induced oscillations propagating can be further improved through a cascade reaction mechanism. It has been discovered that it is possible to considerably enhance the transport efficiency of the biochemical reactions attained at the terminal cell, allowing the cell to use the cascade reaction mechanism to operate more precisely and efficiently. Moreover, an optimal reaction coupling strength has been predicted to maximize the transport efficiency of the terminal cell, uncovering a concrete design strategy for biochemical systems. By using the local mean field approximation, we have presented an analytical framework by extending the stochastic normal form equation to the system perturbed by external signals, providing an explanation of the optimal coupling strength.
Room-temperature synthesis of 2D-Ti3C2Tx nano-sheets by organic base treatment
Authors: Rafiq Sunaina , Gentili Alessandra , Navarra Maria Assunta , Zamparelli Corrado , Betti Maria Grazia , Frisenda Riccardo , Mariani Carlo
Published: June 2023

The growing demand for improved electrochemical performance in energy storage systems has stimulated research into advanced two-dimensional (2D) materials for electrodes. In this work, we obtain a layered MXene compound by exfoliating a titanium aluminum carbide precursor using tetramethylammonium hydroxide (TMAOH) ions in a full room temperature process followed by manual shaking. The hexagonal crystal structure and composition of the layered materials are characterized using different techniques. X-Ray diffraction shows the formation of 2D nano-sheets before and after the TMAOH treatment via its characteristic (002) diffraction peak, bringing to light an increase in the interlayer spacing after treatment. Scanning electron microscopy images confirm the layered morphology, whose composition is determined by energy dispersive x-ray analysis for the bulk material and by x-ray photoelectron spectroscopy for the surface of the obtained compounds. This study demonstrates a promising route to enhance delamination of this MXene 2D material in a low-cost room-temperature approach.
Inhibition and activation of interactions in networked weak prisoner’s dilemma
Authors: Yao Yichao , Zeng Ziyan , Pi Bin , Feng Minyu
Published: June 2023

In the framework of the coevolution dynamics of the weak prisoner’s dilemma, inspired by prior empirical research, we present a coevolutionary model with local network dynamics in a static network framework. Viewing the edges of the network as social interactions between individuals, when individuals play the weak prisoner’s dilemma game, they accumulate both payoffs and social interaction willingness based on a payoff matrix of the social interaction willingness we constructed. The edges are then inhibiting or activating based on the social interaction willingness of the two individuals, and individuals only interact with others through activated edges, resulting in local network dynamics in a static network framework. Individuals who receive more cooperation will be more likely to activate the edges around them, meaning they will participate in more social interactions. Conversely, individuals who receive more defects will do the opposite. Specifically, we investigate the evolutionary dynamics of cooperation under different levels of sensitivity to social interaction willingness and the temptation to defect. Through the simulation, we find that sparse cooperator clusters can expand greatly when social interaction sensitivity and temptation to defect are low. In contrast, dense cooperator clusters form rapidly in a high social interaction sensitivity, which protects the cooperation from high temptation.
Nonequilibrium mixture dynamics: A model for mobilities and its consequences
Authors: Akaberian Maryam , Thewes Filipe C. , Sollich Peter , Krüger Matthias
Published: June 2023

Extending the famous model B for the time evolution of a liquid mixture, we derive an approximate expression for the mobility matrix that couples different mixture components. This approach is based on a single component fluid with particles that are artificially grouped into separate species labeled by “colors.” The resulting mobility matrix depends on a single dimensionless parameter, which can be determined efficiently from experimental data or numerical simulations, and includes existing standard forms as special cases. We identify two distinct mobility regimes, corresponding to collective motion and interdiffusion, respectively, and show how they emerge from the microscopic properties of the fluid. As a test scenario, we study the dynamics after a thermal quench, providing a number of general relations and analytical insights from a Gaussian theory. Specifically, for systems with two or three components, analytical results for the time evolution of the equal time correlation function compare well to results of Monte Carlo simulations of a lattice gas. A rich behavior is observed, including the possibility of transient fractionation.
Fano-resonant propagating plexcitons and Rabi-splitting local plexcitons of bilayer borophene in TERS
Authors: Cao Yi , Feng Yanting , Cheng Yuqing , Meng Lingyan , Sun Mengtao
Published: June 2023

Optical nanocavity provides an opportunity to deeply study the light–matter interaction with notable findings such as Rabi splitting in strong coupling and Fano resonance in weak coupling. Here, we theocratically explore the plexcitons of a bilayer (BL) borophene synthesized on an Ag (1 1 1) film in a tip-enhanced Raman scattering (TERS) system, where the BL borophene is located in the nanocavity between the tip and substrate, stimulated by recent experimental synthesis [Liu et al., Nat. Mater. 21, 35 (2022)]. In the strong-coupling region, the negative real part of the dielectric function of the BL borophene manifests; the BL borophene is of plasmonic properties resulting in Rabi splitting of plexcitons with 310 meV. In the weak-coupling region, the spectra show typical asymmetry with a sharp change between a dip and a peak (Fano resonance). A balanced gain and loss facilitates single-mode lasing in the parity-time symmetry-broken regime, where single-mode lasing with a very narrow half-width is of ultrahigh enhancement factor up to 108. Fano-resonant propagating plexcitons are observed in the dip of Fano resonance, which is extremely sensitive to the excitation wavelength. Our results not only deepen the physical understanding of the plasmon–exciton coupling interaction in the TERS system but also provide a way to manipulate the light–matter interaction in the TERS system.
Protein–ligand interactions from a quantum fragmentation perspective: The case of the SARS-CoV-2 main protease interacting with α-ketoamide inhibitors
Authors: Genovese Luigi , Dawson William , Nakajima Takahito , Cristiglio Viviana , Vallet Valérie , Masella Michel
Published: June 2023

We present a hybrid, multi-method, computational scheme for protein/ligand systems well suited to be used on modern and forthcoming massively parallel computing systems. The scheme relies on a multi-scale polarizable molecular modeling, approach to perform molecular dynamics simulations, and on an efficient Density Functional Theory (DFT) linear scaling method to post-process simulation snapshots. We use this scheme to investigate recent α-ketoamide inhibitors targeting the main protease of the SARS-CoV-2 virus. We assessed the reliability and the coherence of the hybrid scheme, in particular, by checking the ability of MM and DFT to reproduce results from high-end ab initio computations regarding such inhibitors. The DFT approach enables an a posteriori fragmentation of the system and an investigation into the strength of interaction among identified fragment pairs. We show the necessity of accounting for a large set of plausible protease/inhibitor conformations to generate reliable interaction data. Finally, we point out ways to further improve α-ketoamide inhibitors to more strongly interact with particular protease domains neighboring the active site.
Measuring the variability of local characteristics in complex networks: Empirical and analytical analysis
Authors: Sidorov S. , Mironov S. , Grigoriev A.
Published: June 2023

We examine the dynamics for the average degree of a node’s neighbors in complex networks. It is a Markov stochastic process, and at each moment of time, this quantity takes on its values in accordance with some probability distribution. We are interested in some characteristics of this distribution: its expectation and its variance, as well as its coefficient of variation. First, we look at several real communities to understand how these values change over time in social networks. The empirical analysis of the behavior of these quantities for real networks shows that the coefficient of variation remains at high level as the network grows. This means that the standard deviation and the mean degree of the neighbors are comparable. Then, we examine the evolution of these three quantities over time for networks obtained as simulations of one of the well-known varieties of the Barabási–Albert model, the growth model with nonlinear preferential attachment (NPA) and a fixed number of attached links at each iteration. We analytically show that the coefficient of variation for the average degree of a node’s neighbors tends to zero in such networks (albeit very slowly). Thus, we establish that the behavior of the average degree of neighbors in Barabási–Albert networks differs from its behavior in real networks. In this regard, we propose a model based on the NPA mechanism with the rule of random number of edges added at each iteration in which the dynamics of the average degree of neighbors is comparable to its dynamics in real networks.
DFT + μ: Density functional theory for muon site determination
Authors: Blundell S. J. , Lancaster T.
Published: June 2023

The technique of muon spin rotation (μSR) has emerged in the last few decades as one of the most powerful methods of obtaining local magnetic information. To make the technique fully quantitative, it is necessary to have an accurate estimate of where inside the crystal structure the muon implants. This can be provided by density functional theory calculations using an approach that is termed as DFT + μ, density functional theory with the implanted muon included. This article reviews this approach, describes some recent successes in particular μSR experiments, and suggests some avenues for future exploration.
Cross-plane thermal conductivity of h-BN thin films grown by pulsed laser deposition
Authors: Alvarez Gustavo A. , Christiansen-Salameh Joyce , Biswas Abhijit , Puthirath Anand B. , Jeong Eugene , Kwon Jinha , Lee Jaejun , Gray Tia , Vajtai Robert , Ajayan Pulickel M. , Tian Zhiting
Published: June 2023

The distinguished properties of hexagonal boron nitride (h-BN), specifically its atomically smooth surface, large critical electric field, and large electronic bandgap, make it ideal for thin film microelectronics and as an ultrawide bandgap semiconductor. Owing to weak van der Waals interactions between layers, h-BN exhibits a significant degree of anisotropic thermal conductivity. The in-plane thermal conductivity of h-BN has extensively been studied, yet the only measured data of cross-plane thermal conductivity (k⊥) are for exfoliated h-BN films. Exfoliation from bulk crystals is not a sustainable method for scalable production of h-BN due to its low repeatability, low yield, poor control of sample thickness, and limitation to small areas. Thus, it is necessary to investigate the thickness-dependence of k⊥ for thin films grown by a practical growth method, such as pulsed laser deposition (PLD), which enables the production of reliable and large-area h-BN films with a control of film thickness. We grew h-BN using PLD at 750 °C and observed a decreasing trend of k⊥ as thickness increases from 30 to 300 nm, varying from ∼1.5 to ∼0.2 W/(m K). We observed a relatively high k⊥ value for h-BN at a thickness of 30 nm, providing insight into the k⊥ of PLD-grown films suitable for electronics applications.
A high-performance thermal transistor based on interfacial negative differential thermal resistance
Authors: Yang Yu , Zhao Yunshan , Zhang Lifa
Published: June 2023

A thermal transistor, which can achieve the smart, flexible, and precisely controlled thermal management, proves to be a promising thermal device. Recently, thermal transistors based on the negative differential thermal resistance (NDTR) have been regarded as the most feasible configuration considering their simple structures. Among the several methods to implement NDTR, the method of reducing the contact pressure between mated surfaces by using the negative thermal expansion material, thus generating a negative temperature dependent interface thermal conductance and accompanied NDTR, is the most likely to be observed experimentally. In this paper, a thermal transistor based on NDTR is designed by engineering the interfacial thermal resistance. Moreover, we optimize the switching function and the amplification function of the transistor by only adjusting the temperature and the length of the source terminal. As an example, a silicon thermal transistor with a high switching ratio as well as an accurately controlled thermal flux amplification function is discussed at low temperature. The design and optimization of macroscopic thermal transistor will promote the rapid development of thermal functional devices and help to control thermal flux in a more flexible and effective way.
Improved multivariate multiscale sample entropy and its application in multi-channel data
Authors: Li Weijia , Shen Xiaohong , Li Yaan , Chen Zhe
Published: June 2023

Entropy, as a nonlinear feature in information science, has drawn much attention for time series analysis. Entropy features have been used to measure the complexity behavior of time series. However, traditional entropy methods mainly focus on one-dimensional time series originating from single-channel transducers and are incapable of handling the multidimensional time series from multi-channel transducers. Previously, the multivariate multiscale sample entropy (MMSE) algorithm was introduced for multi-channel data analysis. Although MMSE generalizes multiscale sample entropy and provides a new method for multidimensional data analysis, it lacks necessary theoretical support and has shortcomings, such as missing cross-channel correlation information and having biased estimation results. This paper proposes an improved multivariate multiscale sample entropy (IMMSE) algorithm to overcome these shortcomings. This paper highlights the existing shortcomings in MMSE under the generalized algorithm. The rationality of IMMSE is theoretically proven using probability theory. Simulations and real-world data analysis have shown that IMMSE is capable of effectively extracting cross-channel correlation information and demonstrating robustness in practical applications. Moreover, it provides theoretical support for generalizing single-channel entropy methods to multi-channel situations.