bluuebunny/crossref_metadata_2025 huggingface dataset:
Eco-econo-efficiency Based Quota Allocation towards Coal De-capacity Reform Implementation: Case Study from China
Authors: Tao Hongyan , Shu Kejing , Lv Chengwei
Published: August 2023

Reducing coal capacity is an essential part of China’s energy transition, with the formulation of a coal de-capacity quota allocation plan the key to achieving its coal overcapacity reductions. This paper presents a coal decapacity quota allocation mechanism based on a comprehensive consideration of the ecological, economic, and efficiency concerns at the enterprise level to deal with China’s coal overcapacity problems. A multi-objective optimization quota allocation model based on equilibrium strategy is established for the decision makers, in which the ecological concerns are measured by three waste emissions, the economic concern assessed based on the coal de-capacity costs, and the efficiency measured using a DEA method. By introducing a membership function method, the model is transformed into its equivalent single form and solved using LINGO software. To prove the practicality of the model, a case analysis was conducted. The results indicate that due to the different ecological and economic level in each coal mine, the allocation ratio of each coal mine for coal de-capacity is quite different. Compared with the government plan to reduce overcapacity in the mining area, the ecological benefits of the enterprise’s strategy increases by 4.69 million tonnes, and the economic costs has reduced 42.79 million CNY. A sensitivity analysis under different parameters for the decision maker preferences implemented, and the production efficiency changes in the mining areas analyzed and compared. It was found that although coal capacity reduction quota allocations can be affected by the decision makers preferences, the comprehensive ecological, economic, and efficiency objectives at small scale, low-efficiency coal mines should take on additional coal capacity reduction tasks. After the optimal allocations, the efficiencies in all mining areas reached an optimal value.
Evolutionary Game Analysis on Local Governments and Airlines’ Behavioral Strategies in China under Carbon Trading
Authors: Yuan Kaibo , Zhu Mengyuan , Chen Zhaoyang , Li Shuijin , Wang Yu
Published: August 2023

The reduction of carbon emissions by airlines has become a crucial objective in achieving carbon neutrality. However, due to the existing benefits game between airlines and local governments, reducing carbon emissions in the air transport industry is a complex process. Previous research on reducing carbon emissions in the Chinese air transport industry has been divided on which approach to take. This study investigates the potential contribution of a carbon trading mechanism towards carbon emission reduction. Firstly, evolutionary game theory is employed to analyze the complex interactions between local governments and airlines, with the public will being introduced as a constraint in the proposed model. Secondly, the impact of the carbon trading mechanism on the dynamic evolution process and stakeholders is analyzed. Furthermore, the stability of the proposed evolutionary game model is verified through empirical analysis. The results show that the carbon trading mechanism plays a significant positive role in promoting both parties’ objectives, indicating that it is a feasible method for reducing emissions in China’s air transport industry.
Life Cycle Analysis of the Coalbed Methane Industry Based on Technology Paradigm and Data Analysis System Method
Authors: Mao Zhiqian , Fan Lurong , Pan Nizhu
Published: August 2023

With the sharply increasing natural gas demand, coalbed methane (CBM), one of the main unconventional gas, significantly impacts the international energy supply. Driven by the global energy market demand, related technologies have been developed. However, previous studies of the CBM industry mostly focused on the description of a single technical field, lacking integrity and versatility, and unable to systematically describe the development of the technology track of the CBM industry. To summarize the life cycle of the technology development of the CBM industry, this paper proposes a new optimization methodology that combines the technology paradigm theory and data analysis system (DAS). Through data visualization, three technical paradigms are proposed; Competition, diffusion and transfer. Based on the visualization results, this paper discusses the challenges existing in the current CBM industry. It proposes corresponding policy recommendations so that the government can formulate appropriate and accurate subsidy incentive policies.
Analysis on Regional Guidance Mechanism for Promoting Prevention Based on Combination of Traditional Chinese Medicine and Western Medicine
Authors: Geng Ziyang , Zeng Ting , Wang Tao , Deng Likaiying
Published: August 2023

China’s health strategy puts forward the requirement of giving priority to prevention and paying equal attention to Traditional Chinese Medicine (TCM) and Western Medicine. Government should guide the preventive actions with combination of TCM and Western Medicine at regional level. An evolutionary game model for regional strategy pattern of TCM and Western Medicine has been constructed, and the solution of the model has been numerically simulated and analyzed. The enlightenment of analysis conclusions mainly includes three aspects: prevention guidance mechanism that does not weaken therapeutic function of medical service system can be established; in current prevention system dominated by Western Medicine, the cost required to promote TCM prevention is affordable; guidance mechanism cannot avoid polarization between preventive actions of TCM and Western medicine in the long run, but it is possible to promote prevention of them at the same time at initial stage of mechanism implementation. Policy suggestions have been put forward on judgment method of service structure changes of TCM and Western Medicine and on effective influence to regional incomes of TCM and Western Medicine.
Determinants of Credit Ratings and Comparison of the Rating Prediction Performances of Machine Learning Algorithms
Authors: Çetin Ali I˙hsan , Ahmed Syed Ejaz
Published: August 2023

In the literature, new machine learning algorithms are dynamically produced in the field of artificial intelligence engineering and the algorithms are constantly updated with new parameter estimations. The performance of existing algorithms in various business areas is still an important topic of discussion. Also, machine learning algorithms are frequently used in long-term credit ratings, which is an crucially important sub-branch of finance. This study was conducted to determine which popular machine learning model performs better in credit scoring. Artificial Neural Network, Random Forest, Support Vector Machine and K Nearest Neighbor were used to determine the algorithm that is suitable for the structure, attribute content and distribution of the data, and the operating logic of the models. In the study, the long-term credit rating is the target variable and the remaining variables are the features, the prediction performances of these 4 algorithm, which are frequently used in previous studies such as credit rating, credit risk, fraud analysis were compared. After data preprocessing, a classification study was carried out using the features included in the model. The metrics used in the comparison are MSE, RMSE, MAE and accuracy. According to the metrics, RF algorithm showed the best performance in the credit scoring.
Research on the Influence of Mobile Short Video Platform Recommendation Information Characteristics on User Stickiness
Authors: Chen Jingdong , Chen Mo , Wan Yuezhen
Published: August 2023

The outbreak of the scientific and technological revolution has brought about the vigorous development of the digital economy. Many short video APPs have gradually come into people’s sight and become important tools for leisure and entertainment. At this time, improving user stickiness has become the key to their competitiveness and long-term development. As a major feature of short video platform, information recommendation plays an important role in the sticky behavior of users. Therefore, targeted research on the internal mechanism of platform recommendation information features for user stickiness will help to improve the platform user stickiness. Based on the stimulus organism response theory, this paper constructs a theoretical model of the impact of the characteristics of recommendation information on the user’s sticky behavior during the use of mobile short video, and investigates 336 mobile short video platform users through online questionnaires. The research shows that the accuracy, benefit, interest and surprise of mobile short video recommendation information have a positive impact on users’ flow experience and sticky behavior; The flow experience has a positive impact on the sticky behavior of mobile short video users. This paper puts forward management suggestions for the management and operators of mobile short videos to help them optimize the design of their products, and recommends more accurate, profitable, interesting and surprising information based on user characteristics to stimulate users’ flow experience, thus improving users’ stickiness and helping enterprises achieve long-term development.
A Systematic Education Model for International Students Mental Health in China During the COVID-19 Pandemic
Authors: Wu Min , Ren Xiaozhu , Chen Xuanyuan , Hao Xinxin , Hu Xiao
Published: August 2023

The COVID-19 outbreak has a psychological impact on international students in China. Public psychological crisis prevention and intervention, and a timely economic and social restoration have become increasingly important. Focusing on international students in China, this paper summarizes different types of psychological issues and their causes after surveying the students’ mental health status and behavior changes. It proposes a systematic approach to address international students’ mental issues from three dimensions including government management, university education, and social support. It establishes the education model for international students’ mental health during the COVID-19 pandemic.
Does the Tax Cuts Policy Lower Firm Survival Risk? Evidence from China
Authors: Wang Hong , Pang Jingni , Chen Jinghao , Huang Yangzhi
Published: August 2023

This paper examines the effect of tax cuts policy on firm survival risk. We analyze a panel data of China’s listed companies over the period 20082021 based on two different techniques: Kaplan-Meier survival estimator and the Cox proportional hazards model. Our findings reveal that the tax cuts policy has positive and significant effect on improving firms’ survival probabilities. Moreover, compared with the income tax cuts, the value-added tax cuts play a more effective role on improving firms’ survival probability. By dividing firm locations into different regions, we also find that the tax cuts policy exerts a positive influence on firms’ survival probabilities in eastern region, while the positive effect in the central and western regions is relatively weaker. From the perspective of profitability heterogeneity, the results show that the beneficial effect from tax cuts policy on firm survival is more pronounced for firms with weaker profitability.
Nexus between Ease of Doing Business and Foreign Direct Investment: Evidence from 130 Economies
Authors: Xu Xinxin , Hu Yue , Tahir Safdar Husain
Published: August 2023

Based on both yearly data of 130 economies, this paper studies the association between the ease of doing business and FDI from three characteristics, i.e., internationalization, legalization, and facilitation. The results demonstrate that the ease of doing business and its three characteristics, i.e., internationalization, legalization, and facilitation all have a statistical positive influence in attracting FDI inflows. Second, this paper finds that in the legalization of doing business, the resolving insolvency indicator is the most statistically positive on attracting FDI, and in the facilitation of doing business, the paying taxes indicator plays an essential role in attracting FDI. Third, this paper finds that the ease of doing business has a vital impact on FDI inflows in developing countries, but not significant for developed countries. The implications of this paper are helpful for local governments optimizing their business environment to attract FDI.
Research on the safe separation corridor of the combined aircraft and its generation method
Authors: PAN Yihua , ZHANG Qingsong , ZHANG Jincheng , CAI Chengzhi , JIA Shan
Published: August 2023

Aerial safety separation is an important indicator to evaluate the flight performance of medium and low speed combination aircraft. In this paper, the concept of impact box and safe separation corridor will be introduced for the air separation problem of the composite aircraft, and a numerical method for quickly obtaining the safe separation area of the composite aircraft is proposed: the influence box-corridor method, and the suitable separation area generation of a composite aircraft will be studied by this method. The article introduces and simplifies the separation process of a certain type of combined aircraft. The concept of impact box and safe separation corridor and the logic and process of the impact box-corridor method are expounded. On this basis, the method is applied to determine the safe separation area of a single body of a composite aircraft through numerical simulation. Finally, the application of this method to the field of real-time separation of aircraft is extended.
Pareto-optimal control of relative motion in the orbital maneuvering problem of spacecraft with finite thrust
Authors: ISHKOV S A , FILIPPOV G A , ZHOU Xiao , WANG Changqing
Published: August 2023

To solve the time-free rendezvous problem of two spacecraft, the multi-criteria optimization of the relative motion trajectory of the linear motion model in an orbiting cylindrical reference frame is studied. The equations for describing the secular and periodic parameters of the relative motion are obtained. The structure of the nominal control program for the longitudinal motion control variant with finite transversal thrust is investigated in some detail, and its analytical solutions are obtained. An algorithm for solving the Pareto-optimal control program for arbitrary boundary conditions and thrust control acceleration values in the standard time including maneuver time and total time is developed. The algorithm uses the Pareto optimal method to achieve two kinds of multi-objective optimization (total time optimization and fuel optimization). The numerical calculation results on the geostationary planar orbit parameter correction variants are given.
AFDX network equipment fault diagnosis technology
Authors: HU Lei , LIU Yang , GUO Qingchao , SHI Yu , MA Chunyan , ZHANG Jiandong , ZHANG Tao
Published: August 2023

This paper focuses on the network equipment fault monitoring and diagnosis software, and studies the fault diagnosis of the monitored AFDX network based on the network algorithm. Firstly, the range fault characteristic parameters are designed to identify the fault type, and the correlation between the detection results and the fault characteristic parameters at each location can be obtained. Secondly, the data storage management scheme of the first level filtering and the second level caching mechanism is designed for the data collected in the detection. Then, according to the designed fault classification, fault diagnosis methods are given respectively, and the occasional anomalies are identified and suppressed. Finally, the network fault diagnosis verification module is designed, and the experimental verification is carried out from the perspectives of real-time and concurrency. The verification results prove the effectiveness of the method.
A trajectory optimization method for UAV cascade relay broadcast communication system
Authors: LI Dongxia , SONG Siyu , LIU Haitao
Published: August 2023

An unmanned aerial vehicle's(UAV) trajectory optimization is an important way to improve the performance of its relay communication system. The trajectory optimization method for the UAV cascade relay broadcast communication system that uses the decoding and forwarding protocols is studied. Firstly, the expressions of the signal-to-noise ratio of the UAV and the user are given. Then, a joint trajectory optimization method and a distributed trajectory optimization method for cascaded UAVs based on the minimized maximum user interruption probability are proposed. The transmission performance of the system link that uses the two trajectory optimization methods is studied; the mathematical expressions of the relay communication system's traverse capacity and the outage probability of a single user are given. Finally, the influence of the relay communication system's characteristic parameters on the optimal trajectory of the cascade relay UAV and its performance are verified with computer simulations. The simulation results show that the performance of the two trajectory optimization methods is basically the same, thus verifying the effectiveness of the trajectory optimization criterion.
Optimize the corrosion behavior of AISI 204Cu stainless steel in different environments under previous cold working and welding
Authors: Lieth Haider Mahdi , Jabbar Murtadha Abbas , Jassim Raad Jamal , Al-Sabur Raheem
Published: August 2023

Enhancing corrosion resistance in stainless-ssteel alloys is a paramount objective in the petroleum industry. This study investigated the effects of the previous cold working and welding processes on the mechanical properties and corrosion rates of 204 Cu stainless steel in different aggressive environments (crude oil, freshwater, and seawater). The experimental sets were supported by microstructure analysis. The mean weight loss method was employed to determine the corrosion rates, which were optimized using the Taguchi method. The ferrite and austenite phase bands, as well as the deformed portions of austenite, are pushed to flatten out during cold working, which increases the material’s hardness. Cold-worked steels were welded, creating an annealed area around the HAZ in addition to the usual weld zones, which demonstrated partial microstructure recovery and hardness reduction. HAZ showed signs of iron overload and chromium nitride precipitation. Cold-worked specimens only showed reduced corrosion resistance to 30% of the initial rate and reduced thickness. Moreover, the Taguchi optimization technique indicated that the corrosion environment has the most effect on the corrosion rate compared to the cold work ratio for welded and non-welded stainless-steel specimens.
An analysis of the buoyancy and drag parameters in Rayleigh-Taylor dynamics
Authors: Hill Des , Abarzhi Snezhana
Published: August 2023

Rayleigh-Taylor instability (RTI) is of critical important in a broad range of natural and industrial processes and is an intellectual challenge for theoretical studies. In this work, we analyze the scale-dependent linear and nonlinear Rayleigh{Taylor (RT) dynamics within the group theory approach. We link the governing equations, through an associated dynamical system based on space groups, to a momentum model based on scaling transformations. In doing so, we precisely derive expressions for the buoyancy and drag parameters of the momentum model, exactly integrate the model equations and determine solutions for bubbles and for spikes in both early-time and late-time regimes. In particular, we focus on the general situation in which the instability is driven by an acceleration having power-law time dependence. Our analysis provides extensive benchmarks for future research.
Evaluation of chemical composition of seed oil and oil cake of Ailanthus excelsa (Roxb.) and its application
Authors: Pal Vijay , Gour Vinod Singh , Sharma Paras , Choudhary Aarti , Rekadwad Bhagwan Narayan , Singh Joginder , Rani Kanta
Published: August 2023

The purpose of this investigation was to examine the antibacterial activity of oil derived from Ailanthus excelsa (Roxb) as well as the chemical composition of seed oil and the proximate analysis of oil cake. The oil content of the seeds is ∼ 17%. The seed oil was analyzed using GC-MS/FID, and the results showed that it contained a variety of fatty acids, such as linoleic acid, oleic acid, and palmitic acid. When employed with 100 µL, the oil did not demonstrate any antibacterial activity against the bacteria Staphylococcus aureus, Salmonella typhi, Escherichia coli, Pseudomonas aeruginosa, and Bacillus subtilis. The oil does not possess any antifungal action against Candida albicans and Aspergillus flavus. The oil cake is rich in protein and minerals. These findings imply that A. excelsa seed oil and oil cake have the potential to be used in the food and pharmaceutical industries after ascertaining its non-toxic nature and absence of antinutrients. The oil is not having antibacterial activity hence it can be used as a part of nutrient media for bacterial cultures.
Open reduction and polyaxial plating for stemmed knee periprosthetic fractures: A case series
Authors: Gonzalez-Morgado Diego , Andres-Peiro Jose Vicente , Selga Marsa Jordi , Alberto Piedra Calle Carlos , Francesc Nomdedeu Sancho Josep , Teixidor Serra Jordi , Tomas Hernandez Jordi
Published: August 2023

Introduction: Stemmed total knee arthroplasty (STKA) periprosthetic fractures (PPFs) are an emerging problem affecting frail patients. Their surgical fixation is challenging, due to intramedullary involvement and poor bone stock. Polyaxial locking plating has yielded good results in implant-related femur fractures. We hypothesized that this treatment would provide similar results for STKA PPFs. Methods: Retrospective analysis of consecutive patients with a femoral PPF or inter-implant fracture around a knee revision stem who had undergone open reduction and periprosthetic-specific polyaxial plate fixation. Results: We found 14 cases of mean age 85.4 years. Cerclages were used in 80% of cases. Fixation of a mean 8.6 cortices around the revision stem was achieved, with an overall screw density of 1:2 or 1:3. Four patients lost their ability to walk, while four experienced postoperative local complications. Bone healing was achieved in all except one who died during hospitalization. The 13 remaining survived the first year of follow-up. Conclusion: STKA PPFs are an emerging and challenging problem affecting frail patients. Treatment using polyaxial locking plates provides stable fixation allowing early mobilization despite high complication rates.
Alle Kinder fit für die Schule? Die Gestaltung des
Entwicklungsscreenings im Rahmen der Schuleingangsuntersuchung in
Deutschland
Authors: Preuschhof Claudia , Küster Tess , Rademacher Jeanne , Baumgarten Melanie
Published: August 2023

Die Schuleingangsuntersuchung (SEU) liefert wichtige Informationen zum
Förderbedarf eines Kindes und für die
Gesundheitsberichterstattung. Die SEU sollte den neuesten Stand der Wissenschaft
abbilden und Daten von hoher Qualität erzeugen. Dazu muss sie
wissenschaftlichen Gütekriterien genügen sowie
fortwährend evaluiert und weiterentwickelt werden. In Anbetracht der
Relevanz der Daten und des hohen Personalaufwandes muss sich die SEU in Bezug
auf Sinnhaftigkeit, Inhalte und Struktur einer wissenschaftlichen und
öffentlichen Debatte stellen. Dafür ist eine transparente
Kommunikations- und Veröffentlichungspraxis erforderlich. Der
vorliegende Übersichtsartikel hat das Ziel, die öffentlich
verfügbaren Informationen zu Vorgaben der einzelnen Länder
bezüglich Entwicklungsscreenings in der SEU zusammenzutragen und
hinsichtlich Transparenz, Vollständigkeit und wissenschaftlicher
Güte zu bewerten. Während die erfassten Entwicklungsbereiche
stark übereinstimmen, bestehen große Unterschiede im Zeitpunkt
der SEU, ob ein ein- bzw. mehrstufiges Verfahren eingesetzt wird und inwieweit
alle Kinder von Ärzt*innen des Öffentlichen
Gesundheitsdienstes (ÖGD) untersucht werden. SOPESS ist das am
häufigsten in Deutschland eingesetzte Verfahren, für welches
auch hinreichende Gütekriterien aufgezeigt wurden. Für einige
breitflächig eingesetzte Verfahren fehlen vor allem Validierung und
Normierung. Insgesamt gibt es wenig öffentlich verfügbare
Informationen oder wissenschaftliche Publikationen zur SEU durch den
ÖGD. Die Heterogenität der eingesetzten Verfahren in Deutschland
kann als eine Chance für die Weiterentwicklung und Verbesserung der SEU
betrachtet werden. Wünschenswert hierfür wäre eine
kontinuierliche Kommunikation zwischen Verantwortlichen in den Ländern,
eine gründliche wissenschaftliche Begleitung sowie öffentliche
Debatte.
Aminoacylation of Alkenes by Cooperative NHC and Photoredox Catalysis
Authors: Lezius Lena , Reimler Jannik , Studer Armido , Döben Nadine , Hamm Michael , Daniliuc Constantin G.
Published: August 2023

Cooperative NHC and photoredox catalysis has gained significant attention as an emerging research field in recent years. Herein, we report a cyclizing aminoacylation of alkenes, which is enabled through the combination of these two catalytic modes. The key step is a radical/radical cross-coupling between a persistent ketyl radical and a transient benzylic or aliphatic C-radical, which is generated through radical cyclization of an oxidatively formed amidyl radical. Several carbamates, amides and sulfonamides containing an alkene moiety and different acyl fluorides can be used as substrates. The resulting products are obtained in moderate to good yields.
Time-frequency volatility spillovers between Chinese renminbi onshore and offshore markets during the COVID-19 crisis
Authors: Wang Liang , Xiong Xianyan , Cao Ziqiu
Published: August 2023

This article investigates the time-frequency volatility spillovers between Chinese renminbi onshore and offshore markets during the COVID-19 crisis. By employing wavelet analysis, we find that: (i) As the timescale increases, the volatility spillovers between renminbi onshore and offshore markets are gradually significant and bidirectional, and they have increased significantly after the COVID-19 outbreak. (ii) The significant volatility spillovers of the two markets are decomposed into many sub-spillovers on different timescales, most possibly precipitated by heterogeneous behaviors across various investment horizons. (iii) During the COVID-19 crisis, the onshore market has the dominant position on price discovery and leads the offshore market.
Size effect on single pulse all-optical helicity-independent switching in GdFeCo disk arrays
Authors: Gweha Nyoma Danny Petty , Vergès Maxime , Hehn Michel , Lacour Daniel , Hohlfeld Julius , van Dijken Sebastiaan , Malinowski Grégory , Mangin Stéphane , Montaigne François
Published: August 2023

We experimentally demonstrate single pulse toggle switching of the magnetization of GdFeCo disks with perpendicular to film plane anisotropy, which diameter ranges from 3 μm to 400 nm using 35 fs linearly polarized laser pulses. Two different magnetic states can be observed depending on the laser fluence: either a deterministic switching of the disk magnetization or a randomly oriented disk. We report that the fluence required to observe both magnetic states show a non-monotonic behavior with disk diameter and that the smallest disks require the lowest minimum fluence for achieving single pulse all-optical helicity-independent switching. Different evolution of the fluence thresholds for both phenomenon as a function of the disk size is observed and discussed.
Frequency combs generated from rotational Doppler effect
Authors: Liu Zhi-Hong , Cheng Zi-Mo , Zhu Wen-Zheng , Li Hao , Dong Bo-Wen , Lou Yan-Chao , Ren Zhi-Cheng , Ding Jianping , Wang Xi-Lin , Wang Hui-Tian
Published: August 2023

In frequency domain, power spectrum density with evenly spaced discrete lines forms a frequency comb, which has become a fundamental physical concept for wave. Especially, in optical electromagnetic wavebands, an optical frequency comb plays a crucial role for a variety of precision measurement technologies and has become one of the representative breakthroughs in modern physics. To extend the study of frequency comb to other wave region would be an interesting and important task. One significant challenge is to develop a general method suitable to different waves. Here, by manipulation one of the essence natures of wave, orbital angular momentum (OAM), we demonstrate an general approach to produce a frequency comb based on a rotational Doppler effect with the OAM comb. We experimentally generate and verify frequency comb with teeth up to 10. Our results not only provide a general way for the frequency comb generation suitable to various waves but also may open up possibilities for application of frequency comb in more types of wave.
Modeling the functional heterogeneity and conditions for the occurrence of microreentry in procedurally created atrial fibrous tissue
Authors: Kalinin Aleksey , Naumov Vadim , Kovalenko Sandaara , Berezhnoy Andrey , Slotvitsky Mihail , Scherbina Serafima , Aitova Aleria , Syrovnev Vladimir , Popov Mikhail , Kalemberg Andrey , kizi Frolova Sheyda Rauf , Agladze Konstantin , Tsvelaya Valeriya
Published: August 2023

The occurrence of atrial fibrillation (AF), one of the most socially significant arrhythmias, is associated with the presence of areas of fibrosis. Fibrosis introduces conduction heterogeneity into the cardiac tissue and, thus, may be a substrate for spiral wave reentry, which provokes the onset of AF and is often associated with its persistence. Despite results from computer and animal models of cardiac tissues, data on the conditions under which microreentries occur in human tissues are limited. In this work, we conducted a study of the new approach to modeling the fibrous atrial tissue, which takes into account the cellular structure and conduction in fibrosis areas. Using the Potts model, we created a realistic texture of atrial tissues remodeled by fibroblasts and showed the presence of pathways in such a system with a low proportion of fibroblasts. Our study revealed the relationship between the shape of the cells’ action potential, their location in the tissue, and the direction of the wave propagation. The wavefront obtained in the model creates a dynamic heterogeneity of the tissue, which affects the migration and pinning of spiral waves, and explains the formation of microreentries in the cardiac tissue. In the future, such a model can become a potential tool for predictive modeling of AF and the search for ablation target identification.
Modeling and analysis of the magnetic force and stiffness of a low-frequency vibration isolator with axial magnetized magnetic rings
Authors: Li Qiang , Huang Song , Zhang Shengguo , Xu Dengfeng , He Zhaoyun , Li Yaqiong
Published: August 2023

The vibration isolator is a key part of many ultra-precision machines and measuring apparatus. Magnetic suspension vibration isolators (MSVIs) will have excellent application prospects in these instruments to restrain external oscillations. So this paper firstly proposes a new basic configuration of MSVI. Then, in order to study the mechanical characteristics of the MSVI, an analytical expression of the magnetic force is established. The effectiveness of which is demonstrated by the experiment and finite element analysis (FEA). The stiffness of the MSVI is obtained by the derivative of the established analytical magnetic force. Both the axial magnetic force and stiffness appear strong nonlinearity when the inner ring moves at both ends of the fixed outer ring. While the inner ring travels in the middle of the fixed outer one, the axial magnetic force and stiffness indicate approximate linearity with enough bearing capacity. Furthermore, parametric analysis, based on the created magnetic force and stiffness, is performed. The analytical results show that the axial magnetic stiffness may achieve a zero or even negative stiffness value in this range at some size dimensions. The MSVI appears to have a negative stiffness characteristic. More importantly, if a linear and nonlinear positive stiffness spring is combined with the MSVI, it can increase the load capacity of the MSVI. As an example study, the vibration isolation performance of the MSVI is analyzed. The vibration isolation calculation and experiment with the zero stiffness MSVI will be the further focus of the paper.
Competition between full slip and twinning in BCC-Fe: Effect of preloaded stress and temperature
Authors: Veerababu J. , Nagesha A.
Published: August 2023

Slip or twinning is one of the fundamental questions in the deformation studies of metals and alloys. Internal parameters such as generalized stacking fault energy and size and external parameters such as pressure, strain rate, and temperature influence the competition between the full slip and twinning, thus dictating the predominance of one mechanism over the other. In the present investigation, we studied the influence of preloaded stress and temperature on the deformation behavior of BCC-Fe nanowires using molecular dynamics simulations and theoretical analysis. Based on detailed investigations into the energetics associated with slip and twinning, we observed that twinning is the preferred deformation mechanism in BCC-Fe. However, this has been modified by preloaded stresses applied in normal, transverse, and both directions on the nanowire. We observed a slip on {110}, on {112}, and even on {123} planes. The temperature did not alter the inherent twinning nature but linearly decreased the various fault energies.
Effect of dimensionless roughness on cascade flow separation
Authors: Liang Di , Li Yimin , Zhou Zhongning
Published: August 2023

This study examines the impact of dimensionless roughness on flow separation structures and flow characteristics through a combination of experimental and numerical simulation methods. The findings indicate that a specific dimensionless roughness k+ exists for the fixed airfoil that minimizes cascade loss. Furthermore, increasing surface dimensionless roughness can alter the flow separation structure and effectively prevent flow separation. The numerical simulation results indicate that as dimensionless roughness increases, the impact of open separation and separation bubbles on the flow state over the blade surface is reduced or eliminated. In cases where separation occurs in the cascade, increasing dimensionless roughness results in a reduction in the boundary layer thickness and the width of the wake jet, thereby leading to a smoother outlet angle and improved efficiency. Conversely, when there is no separation, increasing dimensionless roughness leads to the accumulation of low-energy fluid at the trailing edge of the cascade. This results in an increase in the boundary layer thickness and the width of the wake loss, a larger outlet angle of the blade, and a decrease in the efficiency of the cascade. By analyzing the influence of dimensionless roughness on flow separation in cascades, engineers can quickly identify the geometric roughness height to suppress flow separation.
Relativistic laser third-harmonic generation from magnetized plasmas under a tapered magnetostatic wiggler
Authors: Abedi-Varaki Mehdi
Published: August 2023

In this work, the third harmonic generated by Gaussian laser pulse propagating in magnetized plasma under the impact of tapered magnetostatic wiggler field is studied. Fundamental equations for analysis of third-harmonic generation by employing the equation of motion, the continuity equation, and the perturbation technique for Gaussian laser pulse in a weakly relativistic regime and the attendance of a wiggler magnetic field are derived. Additionally, the influences of laser strength, wiggler field, plasma frequency, and the δ-parameter on the third-harmonic generation are investigated. The results show that the amount of wiggler frequency required to generate the third harmonic decreases with an increase in the laser strength parameter. Aside from that, the plasma frequency is enhanced with increasing wiggler frequency. Furthermore, it is observed that the efficiency of the generated third harmonic decreases with increasing δ-parameter. In addition, it is found that the efficiency of the generated third harmonic also depends on the time, and the maximum efficiency occurs while the phase matching condition is satisfied. Furthermore, it is seen that the efficiency of the generated third harmonic enhances with increasing plasma frequency. Moreover, it is revealed that the Gaussian laser pulse amplitude has a negligible effect on the third-harmonic efficiency at very low intensities.
High performance InGaN/GaN visible-light field effect phototransistor using polarization induced virtual photogate
Authors: Lv Zesheng , Lu Jiabing , Xu Haoming , Peng Tianzhi , wen Quan , Wang Gang , Jiang Hao
Published: August 2023

Visible-light field effect phototransistors (FEPTs) with high detectivity and high speed are fabricated using a polarization induced photogate in a simple In0.15Ga0.85N/GaN heterostructure, where the pure polarization electric field acts as a virtual photogate of the FEPT and the total In0.15Ga0.85N layer plays the roles of absorber and channel. Experimental results show that the polarization electric field from high quality pseudo-crystalline InGaN/GaN structure can fully deplete the channel layer and leads to an ultra-low dark current. Furthermore, the channel conductivity can be significantly promoted with visible-light illumination. Therefore, the FEPT achieves a high visible-light gain of 6.0 × 104 and a superhigh shot noise limited specific detectivity of 1.5 × 1016 Jones, as well as a high speed with 15 ns/160 ns rise/fall time. The results not only present huge potential in visible-light photodetection, but also provide an insight into the application of polarization effects in wide bandgap semiconductors.
Application of a fluid model in the local energy approximation to numerical simulation of the ionization wave front of negative polarity in He
Authors: Trusov K. K.
Published: August 2023

The fluid equation model in the local energy approximation is applied to computer simulation of the negative ionization wave front in He stimulated by the applied electrostatic field. Numerical calculations are carried out based on 1D dimensionless representation of the equation system, in the context of streamer propagation in this gas. Pooling the known experimental and theoretical data on the ionization-transport coefficients of electrons in He enabled their approximations by the analytical functions within the range of the reduced electric field 10−3–104 Td and integration into the calculation code. The front propagation velocity and spatial thickness along the direction of its propagation, defined by the level 0.1–0.9 of the maximum electric field ahead of the front, and the electron density close on the front tail are calculated depending on the applied electric field strength and presented in the work. The obtained results allowed estimating the ratios of the electron momentum and mean energy relaxation rates to the rate of the changes induced in the gas by the front propagation. The local equilibrium condition of the fluid model validity requires the ratios to exceed the unity repeatedly. Their values are shown to decrease with an increase in the electric field, thus restricting its range from above the approved model application. For example, the admission of their excess over 10 to be sufficient for the electron relaxation within the front leads to the restriction of the application range by about 600 Td (the mean electron energy about 46 eV).
Experimental and numerical study of liquid film by jet impingement: Based on contact angle model
Authors: Wang Sheng-Ju , Shi Zhe-Hang , Yao Tian-Liang , Li Wei-Feng , Lin Qing-Guo
Published: August 2023

Liquid film by jet impingement is widely applied in aerospace, steel quenching, ink-jet printing, and cleaning. In this paper, simulations with the modified contact angle model were used to describe the characteristics of the liquid film. Based on the Hoffman's law and the Tanner's correlation, the contact angle model was constructed and further nested within the Coupled Level Set and Volume of Fluid model. The model determined the movement direction of contact line according to the inner product of the normal vector at the phase interface and the lateral velocity in the cell and then outputted the value of the contact angle. Results showed that the advancing and the receding contact angles of droplet were inappropriate for the simulation of the liquid film. The size of the liquid film obtained by the static contact angle largely depended on the selection of contact angle values. Instead, the modified contact angle model provided an accurate prediction on the morphology and the size of the liquid film.
Characterization and discrimination of some gem silicate minerals adopting LIBS, FTIR, and Raman spectroscopic techniques
Authors: Khedr Amal Abdelfattah , Surour Adel A. , El-Hussein Ahmed , Abdelhamid Mahmoud
Published: August 2023

In this paper, characterization and discrimination of some silicate gems (gemstones and low-gem quality varieties) from ancient Egyptian mines have been performed for the first time adopting molecular and elemental spectroscopic techniques. The selected gem groups are peridot, beryl/emerald, amazonite, and amethyst. In this sense, characterization of the genuine Egyptian gems and the importance of mineralogical and chemical signatures in a historical context as well as the scope of geoheritage can be achieved for the first time. Laser induced breakdown spectroscopy (LIBS) analysis has been found to be an effective method for the discrimination among different gems groups where a characterizing element for each group in a specific spectral window has been found. Raman and Fourier transform infrared (FTIR) spectroscopy spectra have proven to be fingerprints with the ability to distinguish future alteration of the gemstone depending on the molecular vibrational spectroscopy. FTIR provides the functional group that can absorb the infrared radiation and be responsible for the coloring of the gemstones.
In-plane anisotropic mechanical properties of two-dimensional NbOI2
Authors: Cui Yuanyuan , Li Shuqi , Zhang Xiangping , wang Tingjun , Cao Xinyu , Yan Shaohua , Zhang Xiao , Lei Hechang , Tang Gang , Hong Jiawang , Wang Xueyun
Published: August 2023

Two-dimensional niobium oxide diiodide (NbOI2) has recently attracted extensive attention due to its highly anisotropic band structures and rich physical characteristics in electronics and optoelectronics. Nevertheless, mechanical properties of NbOI2 have not been systematically investigated, which are critical parameters for applications. Here, we determine the directional dependence of Young's modulus of thin NbOI2 flakes by using an atomic force microscopy-based nanoindentation technique. We find that Young's moduli along two perpendicular in-plane crystalline axis, the c-axis and the a-axis, were 97.27 ± 2.12 and 51.51 ± 8.21 GPa, respectively. The anisotropic ratio is up to 1.89, which is a high anisotropy value in two-dimensional materials reported so far.
Rapid acquisition of liquid thermophysical properties from pure metals to quaternary alloys by proposing a machine learning strategy
Authors: Xiao R. L. , Liu K. L. , Ruan Y. , Wei B.
Published: August 2023

The establishment of reliable materials genome databases involving the thermophysical properties of liquid metals and alloys promotes the progress of materials research and development, whereas acquiring these properties imposes great challenges on experimental investigation. Here, we proposed a deep learning method and achieved a deep neural network (DNN) interatomic potential for the entire Ti–Ni–Cr–Al system from pure metals to quaternary alloys. This DNN potential exhibited sufficient temperature and compositional transformability which extended beyond the training and provided the prediction of the liquid structure and thermophysical properties for metallic materials with both density functional theory accuracy and classic molecular dynamics efficiency. The predicted results agreed well with the reported experimental data. This work opens a feasible way to address the challenges of rapidly and accurately acquiring thermophysical properties data for liquid pure metals and multicomponent alloys, covering a broad temperature range from superheated to undercooled state.
Toward time resolved dynamic light scattering microscopy: Retrieving particle size distributions at high temporal resolutions
Authors: Urquidi Oscar , Barbosa Natercia , Brazard Johanna , Adachi Takuji B. M.
Published: August 2023

Dynamic light scattering (DLS) is a widely applied technique in multiple scientific and industrial fields for the size characterization of nanoscale objects in solution. While DLS is typically applied to characterize systems under static conditions, the emerging interest in using DLS on temporally evolving systems stimulates the latent need to improve the time resolution of measurements. Herein, we present a DLS microscopy setup (micro-DLS) that can accurately characterize the size of particles from autocorrelation functions built from sub-100 ms time windows, several orders of magnitude faster than previously reported. The system first registers the arrival time of the scattered photons using a time-correlated single photon counting module, which allows the construction of the autocorrelation function for size characterization based on a time window of freely chosen position and width. The setup could characterize both monomodal (60 or 220 nm polystyrene particles; PS) and multimodal size distributions (e.g., mixture of 20 nm LUDOX and 80 nm PS) with high accuracy in a sub-100 ms time window. Notably, the width of the size distribution became narrower as a shorter time window was used. This was attributed to the ability of the system to resolve the sub-ensemble of the broad size distribution, as the broad distribution could be reconstructed by accumulating the distribution obtained by consecutive 80 ms time windows. A DLS system with high temporal resolution will accelerate the expansion of its application toward systems that evolve as a function of time beyond its conventional use on static systems.
Non-equilibrium dissipation laws in a minimal two-scale wake model
Authors: Shao X. , Fang J. , Fang L.
Published: August 2023

The existence of a large-scale non-equilibrium dissipation law (Cε∼Reλ−15/14) has been well documented through various experiments conducted on grid-generated turbulent wake flows. In our previous studies, we have successfully demonstrated the coexistence of a rapid non-equilibrium dissipation law (Cε∼Reλ−2) before the large-scale counterpart in homogeneous isotropic turbulence with inversed or perturbed initial conditions and accordingly developed the closure models. In this paper, we introduce a simplified minimal two-scale wake model, which serves as a simplification of grid-generated turbulence experiments. It is evident that both the large-scale and rapid non-equilibrium dissipation laws coexist in this flow, similar to our previous studies in homogeneous isotropic turbulence. Moreover, we show that the utilization or exclusion of spanwise averages does not significantly affect the qualitative characteristics of non-equilibrium behaviors. Furthermore, by investigating the turbulent/non-turbulent interface, we argue that the presence of coherent structures is not necessarily required to generate the scaling associated with non-equilibrium behavior.