bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on the simulation of single-event burnout in 1.2-kV GaN CAVET
Authors: Wei Yuan , Zhao Yuhao , Xu Binyi , Hu Kaifu , Zhang Xiaodong , Shen Chong
Published: October 2024

The simulation outcomes of single event burnout (SEB) in the common Gallium Nitride (GaN) Current Aperture Vertical Electron Transistor (CAVET) and Single Buffer Layer CAVET (SBL CAVET) were contrasted and elaborated in this thesis. In accordance with the employment of the 1.2-kV GaN CAVET, the boundary of the gate dielectric and source electrode region is the utmost sensitive ion’s strike point to SEB. The simulation of SBL’s robustness CAVET possessing various single buffer layer designs against a heavy-ion was conducted. From this, the compromising of the largest temperature near the source electrode by the doping concentration and the buffer layer’s thickness was realized. When it comes to the heavy ion, under the situation of transferring a linear energy of 0.9 pC/µm vertically, the threshold voltage of SEB for SBL-CAVET is 1, 250 V instead of CAVET’s 650 V.
MBGD-LSTNet-based IGBT aging fault prediction for photovoltaic inverters
Authors: Wang Tingting , Yang Jie , Xu Ziqian , Yu Chao , Liu Yanxi , Liu Xiao
Published: October 2024

The photovoltaic inverter serves as the core component of solar photovoltaic power generation equipment. However, during its operational lifecycle, common issues such as aging of the IGBT on the inverter’s DC side often arise. This aging not only hinders the inverter’s output power and efficiency but also undermines the stable operation of the entire photovoltaic power generation system. In this paper, to address the aging faults of DC-side IGBTs in PV inverters, a novel approach utilizing the Long- and Short-term Time-series Network (LSTNet) is introduced for aging fault prediction, which employs the transient turn-off spike voltage as a key characteristic parameter. Additionally, the Mini-Batch Gradient Descent (MBGT) method is employed to optimize the model, enabling more accurate predictions of aging faults and improved handling of noisy data. By utilizing the accelerated aging dataset for IGBTs provided by the NASA test center, the model is constructed and subjected to rigorous testing for comprehensive evaluation. By analyzing the experimental results for the comparative analysis of the model error, compared with the recurrent neural network and wavelet neural network prediction model, the MBGD-LSTNet network model exhibits reduced error and enhanced prediction accuracy, significantly improving the precision of forecasting aging faults in IGBTs.
Research on metrology method of surface magnetic field based on the nitrogen-vacancy center (NV) in diamonds
Authors: Sun Jinglu , Zhang Peiyan , Ji Rui , Zhang Xiangyang
Published: October 2024

This paper proposes a novel metrology method for surface magnetic fields based on the nitrogen-vacancy (NV) center in a diamond. A coplanar waveguide is used to calibrate the NV center, and its standard values are derived from its simulation results. This metrology method involves leveraging quantum NV scanning technology to capture the Optically Detected Magnetic Resonance (ODMR) spectrum and Rabi oscillation curves of the waveguide, and test data of the surface magnetic field of the coplanar waveguide are meticulously extrapolated through a rigorous fitting process. We compare the test data and simulation results to verify the accuracy of the metrology method. This method promises to enhance the fidelity of magnetic field distribution measurements on chip surfaces, thereby elevating the standards of chip testing accuracy for future applications.
Exogenous data enhancement-driven load cell prognostics
Authors: Zhang Ni , Wang Peng , Wang Chu , Wang Bin , Zhang Yufang
Published: October 2024

Load cells are widely used in various engineering applications. With the increase in service time, its performance tends to decline, resulting in measurement errors. Judging the deterioration degree of the load cell by error and predicting its remaining service life are the key prerequisites to increasing the performance of the load cell and decreasing the maintenance charge. Many factors may cause the load cell to deteriorate, the most prominent of which is temperature. The forecasting method, employing long-term and short-term memory networks, demonstrates strong memory capability for short-term historical data in time series. However, The Long Short-Term Memory Networks prediction algorithm, prone to succumbing to local optima and accumulating errors in long-term prognostication, entails intricate challenges that can not be used for Remaining Useful Life estimation. Therefore, it is suggested that the ambient temperature be used as an additional input to increase the accuracy of the deterioration trend forecast of the load cell. The result of this experiment shows that the forecast accuracy of this method in Remaining Useful Life estimation is 95.6126%, and it is very robust.
Research on fault location and distance measurement methods for low current grounding systems in short distances
Authors: Bai Dikai , Wu Weili , Yang Puwei
Published: October 2024

As the scale of the power system continues to expand, the quality of the power source is crucial to the stable operation of the electric network, making the automation of feeders an inevitable trend in power system development. In this context, this paper takes errors in low current grounding systems as a research subject. The mechanism of grounding fault occurrence is analyzed first, followed by the functional modeling of fault voltage and current, and a formulation describing changes in resistance at the fault point is provided. Subsequently, a neural network-based fault distance measurement model incorporating the resistance relationship is proposed. Extensive simulations of short-distance grounding fault distance measurements were conducted, achieving a high degree of fit. The results demonstrate that the neural network fault distance measurement model offers minimal prediction error for fault distance and significant practical research significance, making it suitable for application in engineering practices.
In-situ Thermal resistance measurement of GaN HEMTs
Authors: Yao Zhanwu , Feng Shiwei , Li Xuan , You Binyu , Lu Xiaozhuang , Bai Kun , Pan Shijie
Published: October 2024

The electrical method allows for quick, non-destructive, and accurate thermal resistance assessment in power devices. However, in practical engineering applications, the presence of decoupling capacitors affects the acquisition of the in-situ thermal resistance of the devices. Therefore, periodic thermal resistance monitoring requires repeated disassembly of the devices, which can introduce new reliability issues. This paper employs an operational circuit design to develop a method for in-situ thermal resistance measurement. The feasibility of this method is validated through the analysis of static and dynamic characteristics.
Research on optimal scheduling of virtual power plant considering demand response under carbon-green certificate trading mechanism
Authors: Yi Yingmin , Zhou Dingsong , Yuan Yiwei , Yu Yongjun
Published: October 2024

With the increasingly serious environmental problems and the randomness of wind-power output, the virtual power plant (VPP) has a positive significance for realizing the dual carbon goal and promoting the stable operation of the power system. To minimize the cost and the carbon emission of VPP operation, this paper proposes a VPP optimal dispatching model considering demand response (DR) under the carbon-green certificate trading mechanism. Firstly, the VPP operation architecture, which can meet various load requirements of electric heating and cooling, is established, and each component equipment of the system is modeled. Afterward, the price and alternative demand response models are constructed, respectively, and the carbon trading (CT) and green certificate trading (GCT) models are analyzed. Then, considering energy purchase cost, system maintenance cost, and carbon-green certificate trading cost, a low-carbon economic dispatching model is formulated to minimize the operational costs of the VPP throughout the dispatching cycle. Finally, the optimization model is solved; the total operating cost of the VPP under this model is 16633.15 yuan, and the carbon emission is 6094.75 kg. Experimental results prove that this optimized model can reduce system operational costs while simultaneously considering environmental benefits.
Research on clustered routing optimization-based improved ant colony algorithm
Authors: Long Xin , Wang Jianxin
Published: October 2024

This paper addresses limitations in the traditional LEACH protocol, characterized by singular considerations in cluster head election and a single-hop data transfer mode, leading to imbalanced network electricity and early node depletion. An enhanced LEACH protocol is proposed, incorporating an improved ant colony algorithm. During cluster head election, the algorithm integrates energy, distance, and density factors to calculate the probability of node election, choosing the most suitable candidate. To create links and speed up data transfer, the method uses the augmented ant colony algorithm to select the finest routes from each cluster head to the Sink during the data transmission phase. The outcomes of the simulation experiment demonstrate the improved protocol performs more effectively in balancing network energy usage, boosting network data gathering, and prolonging network lifetime compared to the traditional LEACH protocol.
A classification method for composite power quality disturbance based on model-agnostic meta-learning under small sample condition
Authors: Liu Yan , Li Hange
Published: October 2024

The classification of composite power quality disturbances (CPQD) in complex power system environments faces challenges due to model establishment and limited sample size, thereby limiting the effectiveness of traditional classification algorithms. This paper proposes a CPQD classification method tailored for small samples, leveraging the model-agnostic meta-learning (MAML) algorithm to address these issues. Analyzing the MAML algorithm, a CPQD classification network is built and implemented, and a CPQD classification comparison experiment is designed. Results demonstrate that, even with a mere five samples, the proposed method significantly improves classification accuracy by at least 20% compared to DT, KNN, and CNN. This innovation provides a viable new approach for CPQD classification in small sample conditions.
Numerical characteristics of DC breakdown and paschen curve of CF3I-N2 mixtures at low pressure
Authors: Wu Yifan , Wu Hao , Gao Jiamao , Yu Shimin , Chen Zhipeng , Jiang Wei , Wang Zhijiang
Published: October 2024

In this study, the DC breakdown characteristics of CF3I-N2 mixtures at low pressure are investigated and compared with those of pure CF3I to assess their insulating properties. Utilizing the particle-in-cell/Monte Carlo collisions (PIC/MC) model, we explore the breakdown process in detail, analyzing electron and ion kinetics across various phases. Our findings reveal that the CF3I-N2 mixture exhibits a faster breakdown rate than pure CF3I but requires more time to achieve a steady state. Additionally, we examine the Paschen curve of CF3I-N2 at varying pressures, discovering that the insulating performance improves with higher CF3I proportions at increased pressures. This study contributes to understanding the insulating behavior of CF3I-N2 mixtures, offering insights for their application in environmentally friendly high-voltage insulation technologies.
Study on intensive grounding design of UHV DC transmission lines in permafrost regions based on conductive concrete foundation
Authors: Zeng Qinghe , Wang Xiaoqing , Li Wenrong , Yang Yueguang , Zhou Jiayi , Chen Jiale , Nie Pei , Shen Zheng
Published: October 2024

The tower grounding device plays an indispensable role in the lightning protection and grounding of transmission lines. Reducing the grounding resistance of the tower grounding device is an important means to improve the lightning resistance of the line. However, the difficulty of reducing resistance in permafrost areas is a major challenge in engineering. Currently, there is still a lack of intensive grounding solutions in permafrost areas. Based on this, this article proposes two grounding devices using a conductive concrete foundation, establishes simulation calculation models using the boundary element method (BEM), studies the grounding characteristics under different structural parameters, and obtains an intensive grounding design plan for transmission lines in permafrost regions, providing practical design references for the intensive grounding design of transmission lines in permafrost regions.
Distributed cooperative planning for multi-agent electricity energy substitutions
Authors: Gao Zihan , Zhou Min , Zhang Sirui , Fang Jinghui , Bu Fanpeng , Wang Linlin
Published: October 2024

A distributed bi-level cooperative planning model for multi-agent electricity energy substitutions is established in this paper. The upper layer establishes the regional power flow model for distribution networks in this model. In contrast, the lower layer determines capacities and sizes for industrial electric boilers, building electric heat pumps, and agricultural electric flue-curing tobacco machines in different nodes. The connection between the upper and lower layers is crucial for maintaining power balance. A bi-level optimization algorithm is applied to address this issue to enable autonomous decision-making and facilitate electricity energy substitutions. Case analysis is then conducted to validate the proposed model’s effectiveness.
Simulation study on single-event burnout of 550 V double RESURF SOI Lateral IGBT
Authors: Zhao Chongning , Hu Dongqing , Zheng Yuechao , Jia Yunpeng , Zhou Xintian , Wu Yu , Tang Yun
Published: October 2024

Providing an additional hole extraction path can significantly enhance the resistance to single-event radiation of SOI-LIGBT devices. This paper designs a 550 V Double RESURF SOI-LIGBT device and studies its single-event effects through simulation. The results indicate that the designed NCSP-LIGBT structure significantly improves resistance to single-event radiation without excessively sacrificing conduction performance.
A novel array connection strategy for improving power generation efficiency of photovoltaic systems during localized shading
Authors: Chen Yichao , Wang Yizhou , Li Zichao , Zhu Yichao , Sun Yuxiao
Published: October 2024

To improve the photovoltaic (PV) system in the local shadow when the power generation efficiency, a PV module series DC/DC converter is the basic unit for a new form of photovoltaic array—distributed converter photovoltaic arrays. This paper selects the DC/DC as a buck converter. The maximum power is tracked by the buck converter with each PV module to realize the maximum power tracking of the uneven irradiation and the inconsistency of output characteristics caused by manufacturing differences and to avoid the complexity of the maximum power tracking algorithm at the same time, and to improve the system power generation efficiency significantly. The theoretical analysis of the connection method is carried out first to prove its feasibility. Finally, a string-type two-stage PV power generation system is constructed through Matlab/Simulink, and a simulation comparison between the traditional PV array and the new array is carried out. The results verify that the new array connection can significantly improve the power generation efficiency.
Microstrip antenna array reducing mutual coupling with split ring resonators branches and split ring resonators slots
Authors: Wang Xin , Yang Kai , Zhao Yi
Published: October 2024

A compact decoupling microstrip antenna array with high isolation by using two methods, including SRR branches and SRR slots, is proposed, whose adjacent unit’s center-to-center distance is 0.35λ. Parasitic patches and air cavities are introduced to achieve broadband characteristics of antenna elements. Spatial coupling is reduced by loading SRR (Split-ring resonator) branches between two feeding elements. Moreover, surface current coupling on the floor can be blocked by SRR slots etched on the floor. Simulated and measured results reveal that the designed antenna impedance bandwidth covers 6.7GHz ~ 8.7GHz (26%). The isolation within the working frequency band is better than 22dB. The prototype of the proposed antenna is easy to fabricate, which provides a feasible solution for achieving high isolation between multiple antennas in engineering.
A data association method based on multi-radar detection of GEO targets
Authors: Wang Linfeng , Lou Dingli , Zhang Shuo , Bu Linsheng
Published: October 2024

To enhance the association capability between measurements during the detection of dense geosynchronous equatorial orbit (GEO) targets, this article presents a data association method based on multi-radar detection of GEO targets. The proposed method utilizes range and velocity data from each radar station and employs direct solution and least squares methods to estimate the spatial position and velocity information of the targets, considering the spatial geometric relationships. Furthermore, a test statistic is constructed by using the Mahalanobis distance between the estimated and measured values of the targets’ spatial position and velocity. Finally, hypothesis testing is employed to achieve target association among different radar stations. The simulation results demonstrate that the proposed target association algorithm maintains a high level of correct association probability even for GEO targets with spatial distance differences in the kilometers range.
Research on outage performance of underground CR-STBC-NOMA communication system assisted by RIS
Authors: Yin Bin , Li Meiling , Ning Yonghong , Song Shizhen
Published: October 2024

With the rapid development of the sixth-generation wireless communication network technology and smart mines, the construction of wireless communication networks in mines is becoming the key to the construction of smart mines. Due to the complex structure and diverse directions of underground tunnels, the propagation of signals in underground wireless communication networks faces problems such as shadow fading, multipath effects, and propagation blocking. A CR-STBC-NOMA (Cognitive Radio Space Time Block Coding Non-Orthogonal Multiple Access) communication system model has been built for underground applications with the assistance of Reflecting Intelligent Surface (RIS) to address the aforementioned issues. Based on the power limitation conditions for secondary network users in the cognitive network of the Underlay mode, the outage probability of users in the RIS-assisted underground CR-STBC-NOMA communication system was derived. The impact of factors such as the number of RIS reflection units, fading coefficient, and power limitation threshold on system outage performance was analyzed. The outage probabilities of the CR-STBC-OMA communication scheme and the CR-STBC-NOMA scheme were compared, and it was verified that the RIS-assisted CR-STBC-NOMA scheme has better outage performance.
Research on underwater target localization technology based on active and passive electric field
Authors: Wang Haixin , Zhang Hongfeng , Geng Weizhi , Xu Yidong , Jia Peisong , Li Beiming
Published: October 2024

Aiming at the issue that in view of the common underwater target electric field detection and localization technology, its electric signal attenuation in the water is faster and easy to be affected by the underwater complex environmental noise, which affects the detection performance of the problem, the paper carries out a research based on active and passive electric field detection and localization technology. First, a target electric field detection and localization system is designed. Then, two sets of basis functions in the horizontal and vertical directions are derived based on this detection system model, and then the detection and localization of underwater targets are realized by energy calculation. Finally, the image fusion algorithm of wavelet transform is adopted to further realize the detection and localization of underwater targets in a two-dimensional plane through the form of a heatmap. All the above contents are experimentally verified by simulation tools, and the experimental results show that compared with the traditional electric field detection and localization techniques for underwater targets, the method in this paper has better performance in the environment with a lower signal-to-noise ratio.
Design and simulation of an S-band RF photogun for a linac-injector for the SYLA FEL
Authors: Ashanin Ilia A. , Bondarenko Taras V. , Gusarova Mariia A. , Kliuchevskaia Yulia D. , Lalayan Mikhail V. , Polozov Sergey M. , Rashchikov Vladimir I. , Vladimirov Mikhail V.
Published: October 2024

Currently,

the 4th generation synchrotron radiation source SYLA (Synchrotron + Laser)
is being developed at NRC «Kurchatov Institute». The

SYLA
will

include
of a free electron laser (FEL) and a 6 GeV storage ring with a 7BA lattice, which will allow obtaining a transverse emittance value of about 50 pm·rad. A linear accelerator for full energy is considered as both the main top-up injector into the storage ring and a driver for FEL. To generate high-brightness bunch trains for FEL, an S-band radiofrequency (RF) gun with a photocathode based on 3.5-cells π-mode standing wave accelerating structure at operating frequency of 2.8 GHz will be used. In this paper, the general concept of the RF photogun is proposed and briefly discussed. An optimization of beam dynamics is performed, electrodynamics parameters are found, fields distribution in the cavity and coaxial RF coupler are provided. Thermal analysis of the structure presented is performed.
Multifunctional nano co-delivery system for efficiently eliminating neuroblastoma by overcoming cancer heterogeneity
Authors: Huang Shungen , Yang Xian , Gao Yajuan , Huang Haoying , Li Tuanwei , Li Meng , Wu Feng , Yang Hongcao , Li Chunyan
Published: October 2024

The high heterogeneity of neuroblastoma (NB) is currently the main challenge in clinical treatment, impeding the complete eradication of the tumor through monotherapy alone. In this study, we propose a combination strategy using a targeted nano co-delivery system (ADRF@Ag2Se) comprising phototheranostic agents, differentiation inducers and chemotherapy drugs for sequential therapy of NB. Upon intravenous injection, ADRF@Ag2Se demonstrates effective tumor targeting by the specific binding of AF7P to MMP14, which is overexpressed on the surface of NB cells. Subsequent implementation of local photothermal therapy (PTT) leverages the robust photothermal conversion capabilities of the amphiphilic photothermal reagent PF. This is followed by the temperature-triggered release of differentiation-inducing agent 13-cis-retinoic acid and chemo-drug doxorubicin to synergistically eliminate the residual lesions. This nanotherapeutic strategy facilitates in vivo targeted delivery and PTT under the supervision of NIR-II fluorescence, and it also enhances the chemotherapeutic response through differentiation induction of poorly differentiated cancer cells. In the NB tumor model, this co-delivery strategy effectively inhibited tumor growth and significantly prolonged the survival of the mice.
Detecting methane emissions from palm oil mills with airborne and spaceborne imaging spectrometers
Authors: Valverde Adriana , Roger Javier , Gorroño Javier , Irakulis-Loitxate Itziar , Guanter Luis
Published: October 2024

Methane (CH4) emissions from human activities are a major cause of global warming, necessitating effective mitigation strategies. In particular, the palm oil industry generates palm oil mill (POM) effluent, which continuously emits methane into the atmosphere. Satellites are becoming a powerful tool to detect and quantify methane emissions, but there is no evidence of their ability to monitor those from POM ponds. In this work, we have tested the potential of methane-capable satellite instruments to detect and quantify emissions from these ponds. We have focused on the satellite missions with the highest sensitivity to methane emissions, namely the GHGSat commercial constellation and the PRISMA, EnMAP, and EMIT imaging spectroscopy missions. We have also tested the AVIRIS-NG airborne imaging spectrometer. We report three methane plumes from POMs in Indonesia with GHGSat and two in Colombia with AVIRIS-NG. In the cases of EnMAP, PRISMA and EMIT, we observed substantial methane concentration enhancements over several ponds in Indonesia, Malaysia, and Colombia. It remains unclear whether they are due to retrieval artifacts caused by the particular albedo of the ponds, although the low spatial correlation between those enhancements and the ponds suggests that at least a fraction of the enhancements is caused by real emissions. By leveraging advanced imaging techniques and satellite data, this research contributes to progressing strategies to address new methane emissions sources with high mitigation potential, providing a first step toward the satellite-based monitoring of methane emissions from POMs.
FROT: A Framework to comprehensively describe radiative contributions to temperature responses
Authors: Monteiro Estela A , Silvy Yona , Hohn David , Burger Friedrich A , Frölicher Thomas L , Mengis Nadine
Published: October 2024

Different human activities and associated emissions of CO2 and non-CO2 radiative forcing agents and feedbacks determine the final state of Earth’s climate. To understand and explain contributions to global temperature changes, many emission-based metrics have been employed, such as CO2-equivalent or -forcing equivalent. None of these metrics, however, include dynamic responses from Earth system feedbacks in terms of carbon and heat redistribution, known to play an increasingly important role in ambitious mitigation scenarios. Here we introduce a framework that allows for an assessment of such feedbacks in addition to CO2, non-CO2 anthropogenic forcing and natural external variability contributions. FROT (Framework for Radiative cOntributions to Temperature response) allows for an assessment of components of direct radiative impact to the system (climate forcing), as well as Earth system feedbacks concerning heat and carbon. The framework is versatile in terms of applications and allows for exploring individual components contributions to, for example, temperature stabilisation simulations, or comparisons in different models and scenarios, as it can reasonably explain their simulated temperature variability. Here, we apply FROT to both an intermediate complexity and a fully coupled Earth system model, as we simulate highly ambitious mitigation scenarios. Comparing temperature stabilisation scenarios, we can show that both net-zero CO2 emissions and small amounts of positive CO2 emissions could lead to a stable global temperature trajectory. Our assessment reveals that the effects of non-CO2 climate forcings, especially the development of sulphate aerosols in the atmosphere, and the dynamics of the carbon cycle, play a pivotal role in the final level of warming and in enabling a temperature stabilisation. Under highly ambitious climate mitigation scenarios it becomes crucial to include Earth system feedbacks, specifically ocean heat uptake, to understand interannual to decadal temperature development, since previously secondary processes now become increasingly dominant. Our framework offers the opportunity to do so.
Seasonal prediction of North Atlantic sea surface temperature anomalies using the LSTM machine learning method
Authors: Xu Chang , Yan Xiaoqin , Tang Youmin
Published: October 2024

Sea surface temperature anomalies (SSTAs) over the North Atlantic (NA) have a significant impact on the weather and climate in both local and remote regions. This study first evaluated the seasonal prediction skill of NA SSTA using the North American multi-model ensemble and found that its performance is limited across various regions and seasons. Therefore, this study constructs models based on the long short-term memory (LSTM) network machine learning method to improve the seasonal prediction of NA SSTA. Results show that the seasonal prediction skill can be significantly improved by LSTM models since they show higher capability to capture nonlinear processes such as the impact of El Niño-Southern Oscillation on NA SSTA. This study shows the great potential of the LSTM model on the seasonal prediction of NA SSTA and provides new clues to improve the seasonal predictions of SSTA in other regions.
CVD graphene with high electrical conductivity: empowering applications
Authors: Lv Shuliang , Liu Haihui , Yan Fuchao , Lu Wenhao , Mao Boyang , Zhang Jincan
Published: October 2024

Graphene is an extraordinary material boasting a unique structure, enthralling properties, and promising application vistas. Particularly, the remarkable electrical conductivity of graphene confers it with an inimitable superiority in multiple fields. Endeavors have been continuously made to progressively elevate the conductivity of graphene materials that are synthesized using chemical vapor deposition (CVD), the primary means to prepare high-quality graphene in batches. From this perspective, we offer a comprehensive analysis and discussions on the growth, transfer, and post-treatment strategies evolved towards highly conductive graphene over the past five years. Large-area graphene films, ranging from monolayer to multilayer ones, are initially addressed, succeeded by graphene-based composites which enable traditional metals and non-metal materials to showcase novel or enhanced electrical performances. Eventually, an outlook for future directions to achieve higher electrical conductivity and to develop novel applications for CVD graphene materials is provided.
Towards invertible 2D crystal structure representation for efficient downstream task execution
Authors: Shibaev Egor , Ustyuzhanin Andrey
Published: October 2024

In the study of MoS2 lattice defects, we explore the use of Siamese neural networks to create invariant embeddings, which respect the crystalline symmetry of the lattice. By training our model with contrastive learning, we successfully differentiate configurations with varying defects, achieving perfect accuracy in recognizing equivalent placements. Our method showcases the capability to predict physical properties like formation energy per site and the bandgap with strong performance across both low and high-defect density scenarios, outperforming traditional methods when enhanced with polynomial features. Despite its effectiveness, the model presents limitations at high defect densities, indicating a need for further refinement. Our approach lays the groundwork for reverse-engineering processes. Thus, we open pathways for generative models that can navigate from specified property ranges to optimal defect configurations, fostering an efficient solution-space exploration for bespoke material synthesis.
Local heating at the running crack tip in bcc iron according to molecular dynamics
Authors: Hora Petr , Machová Anna , Červ Jan , Kordik Jozef
Published: October 2024

This study presents estimates of a possible temperature rise at the crack tip from three dimensional (3D) atomistic simulations of fracture via molecular dynamics (MD) technique. Simulations start from an initial temperature of 0 K. The pre-existing edge crack was loaded in tension mode I. Crack initiation in MD is accompanied by surface dislocation emissions and later by a cross slip of the emitted dislocations into other slip systems. This leads both to stress waves radiation and to local heating in the plastic zone created by these dislocations. The local heating at the crack tip in the surface layers reaches a level of 480–500 K at some atoms, but an average temperature in the plastic zone is lower and depends on a chosen crack tip zone size. In the bulk crystal, where no dislocation emission (i.e. no plastic zone) has been realized, no significant heating is observed at the crack tip. MD results at the free sample surface comply with experimental data for ferritic steels with a pre-existing notch, loaded (quasi-statically) in mode I, as well as with some continuum predictions.
Failure behavior study of EB-PVD TBCs under CMAS corrosion and thermal shock cycles
Authors: Luo Yi , Zhang Jiawei , Dong Qicai , Ning Aimin , Yu Yun
Published: October 2024

Calcia-magnesia-alumino-silicate (CMAS) erosion has become a major obstacle, limiting the operating temperature and service life of Thermal barrier coatings (TBCs) in aircraft engines. Constructing simulation environments that replicate TBCs’ working conditions and exploring online, non-destructive detection techniques are reliable approaches to studying coatings’ failure, representing both a global research hotspot and a challenge in this field. The paper presents an initial endeavor to establish a simulation experiment for TBCs in aviation-engine within a CMAS environment. Experimental results show that electron beam physical vapor deposition (EB-PVD) Y2O3-stabilized ZrO2 (YSZ), one of the mainstream TBCs technologies, produced 20% surface spallation after 50 thermal-shock cycles under simulated CMAS corrosion conditions. Testing and analysis of the macroscopic and microscopic structures of the failed samples, combined with SEM, EDS, and XRD findings, revealed significant physical and chemical interactions between the ceramic layer and CMAS deposits, as well as phase transformation within the coatings, leading to substantial alterations in mechanical properties and ultimately causing the failure of EB-PVD YSZ.
Biological effectiveness of uniform and nonuniform dose distributions in radiotherapy for tumors with intermediate oxygen levels
Authors: Chvetsov Alexei V , Pugachev Andrei
Published: October 2024

Objective. We propose a criterion of biological effectiveness of nonuniform hypoxia-targeted dose distributions in heterogeneous hypoxic tumors based on equivalent uniform aerobic dose (EUAD). We demonstrate the utility of this criterion by applying it to the model problems in radiotherapy for tumors with different levels of oxygen enhancement ratio (OER) and different degrees of dose nonuniformity. Approach. The EUAD is defined as the uniform dose that, under well-oxygenated conditions, produces equal integrated survival of clonogenic cells in radiotherapy for heterogeneous hypoxic tumors with a non-uniform dose distribution. We define the dose nonuniformity effectiveness (DNE) in heterogeneous tumors as the ratio of the EUAD(D
N) for a non-uniform distribution D
N and the reference EUAD(D
U) for the uniform dose distribution D
U with equal integral tumor dose. The DNE concept is illustrated in a radiotherapy model problem for non-small cell lung cancer treated with hypoxia targeted dose escalation. A two-level cell population tumor model was used to consider the hypoxic and oxygenated tumor cells. Results. Theoretical analysis of the DNE shows that the entire region of the OER can be separated in two regions by a threshold OERth: (1) OER > OERth where DNE > 1 indicating higher effectiveness of nonuniform dose distributions and (2) OER < OERth where DNE < 1 indicating higher effectiveness of uniform dose distributions. Our simulations show that the value of the threshold OERth in radiotherapy with conventional fractionation is significant in the range of about 1.2–1.6 depending on selected radiotherapy parameters. In general, the OERth increases with reoxygenation rate, relative hypoxic volume and dose escalation factor. The threshold value of OERth is smaller of about 1.1 for hypofractionated radiotherapy. Significance. The analysis of dose distributions using the DNE shows that the uniform dose distributions may improve biological cell killing effect in heterogeneous tumors with intermediate oxygen levels compared to targeted nonuniform dose distribution.
Change-point detection in anomalous-diffusion trajectories utilising machine-learning-based uncertainty estimates
Authors: Seckler Henrik , Metzler Ralf
Published: October 2024

When recording the movement of individual animals, cells or molecules one will often observe changes in their diffusive behaviour at certain points in time along their trajectory. In order to capture the different diffusive modes assembled in such heterogeneous trajectories it becomes necessary to segment them by determining these change-points. Such a change-point detection can be challenging for conventional statistical methods, especially when the changes are subtle. We here apply Bayesian Deep Learning to obtain point-wise estimates of not only the anomalous diffusion exponent but also the uncertainties in these predictions from a single anomalous diffusion trajectory generated according to four theoretical models of anomalous diffusion. We show that we are able to achieve an accuracy similar to single-mode (without change-points) predictions as well as a well calibrated uncertainty predictions of this accuracy. Additionally, we find that the predicted uncertainties feature interesting behaviour at the change-points leading us to examine the capabilities of these predictions for change-point detection. While the series of predicted uncertainties on their own are not sufficient to improve change-point detection, they do lead to a performance boost when applied in combination with the predicted anomalous diffusion exponents.
Machinability characteristics study on hibiscus rosa-sinensis reinforced polymer composites using soft computing techniques
Authors: Shetty Sawan , Shetty Raviraj , Nayak Rajesh , J P Supriya , Hegde Adithya
Published: October 2024

Understanding the drilling behaviour of composite materials is crucial for optimizing their manufacturing processes and enhancing their applicability across various industries. In this study, the drilling process of Hibiscus Rosa-Sinensis Polymer matrix composites is investigated due to the significance of investigating such advanced and sustainable composite materials for their potential applications. Hibiscus Rosa-Sinensis Fibers are extracted and processed from the outer bark of the hibiscus plant, are incorporated into polymer matrices in varying weight percentages (0 Wt%, 10 Wt%, 20 Wt%) to form discontinuously reinforced polymer composites. Samples with uniform dimensions of 150 × 75 × 15 mm, are used for the drilling operation using Ace Micromatic DTC-400 instrument. The project focuses on analysing the influence of key drilling input parameters such as Spindle speed, Feed rate and HRS (Hibiscus Rosa-Sinensis) Fiber weight percentage on the Thrust Force (N) and Torque (N-m) generated during drilling operations. Taguchi’s Design of Experiments with L27 orthogonal array is used to systematically optimize the input parameters to gain insights into the drilling behaviour of these composite materials. Further a second order mathematical model has been generated for Thrust Force and Torque using Response Surface Methodology (RSM). Thrust Force and Torque during drilling are measured using 9257 BA KISTLER Dynamometer coupled with DynoWare 2825 A software. The findings of this study not only contribute to a deeper understanding of the drilling process but also hold significant implications for industries reliant on composite materials. From aerospace to automotive sectors, where lightweight and durable materials are essential, to construction and renewable energy industries seeking sustainable alternatives, the application potential of hibiscus Rosa-Sinensis Fiber-reinforced composites is vast. By elucidating the intricate dynamics of drilling operations on these materials, this research paves the way for enhanced manufacturing processes and the development of advanced composite structures tailored to meet the demands of diverse industrial applications.
Comprehensive glass/banana fiber characterization with zirconium carbide filler-reinforced hybrid composites for lightweight structural applications
Authors: Muniyan Vijayan , Suganya Priyadharshini Ganesan , Thiagarajan Velmurugan , Palanisamy Senthamaraikannan , Suyambulingam Indran
Published: October 2024

The enhancement of the properties of fiber-based polymer composites is generally possible by the hybridization of fibers. Using synthetic and natural fibers in the composites will enhance the applications, and the problem of voids is solved by using fillers. Mixing banana fiber with glass fibers creates a lightweight yet robust material for architectural elements such as panels and insulation. The current investigation encompassed the production of a glass/banana hybrid composite by integrating a Zirconium carbide (ZrC) filler via compression molding methodologies. The filler proportion varied at five levels: 0 wt%, 0.5 wt%, 1 wt%, 1.5 wt% and 2 wt%, within an epoxy resin matrix. The composite materials underwent mechanical, water absorption, and vibration analysis. Furthermore, the fractured surface was examined using a field emission scanning electron microscope (FESEM) better to understand the interactions between the fibers and the matrix. The initial findings indicated that the incorporation of Banana and glass fibers in composite materials has the potential to achieve an optimal balance between strength and versatility. The key findings include a considerable increase in tensile, flexural, and impact strengths with 1.5 wt% ZrC filler, with improvements of up to 34.5% in impact strength and 44.7% in compressive strength over the unfilled composite.
Investigation of hydrothermal characteristics and entropy generation in a microchannel heat sink with elliptical fins
Authors: Xue Lirui , Liu Chang , Wen Junqi , Shi Yiming , Yan Ziyi , Meng Siyu , Fu Kepu , Chen Haitao , Xia Changquan , Qian Qinyu , Cheng Liwen
Published: October 2024

As the integration of microelectronic devices continues to increase, thermal management issues become increasingly prominent. Microchannel heat sinks are effective for heat dissipation in high heat flux microelectronic devices. This study designs five elliptical finned microchannel heat sinks with different aspect ratios (γ) while maintaining a constant elliptical area to enhance heat transfer performance. The values of γ are 0.74, 0.86, 1, 1.17, and 1.35, respectively. Over the Reynolds number (Re) range of 293 to 740, the hydrothermal characteristics and entropy generation of the microchannels with elliptical fins (MC-EFs) are investigated through numerical simulations. The thermal enhancement mechanism of MC-EFs is analyzed via flow, temperature, and pressure fields. The optimal γ value is determined by maximizing the overall performance factor (OPF) and minimizing the augmentation entropy generation number (N
s,a). Results indicate that introducing elliptical fins in the straight microchannel (SMC) significantly improves heat dissipation. An increase in γ enhances thermal performance but also raises flow resistance. Specifically, when γ increases from 0.74 to 1.35, the Nusselt number (Nu) improves by 10.71%-25.64%, and the friction coefficient (f) increases by 30.92%-57.27%. Overall, at Re = 740, the OPF of the MC-EF with γ = 1.35 reaches a maximum of 1.285, and at Re = 597, the N
s,a for this configuration is minimized to 0.578. These findings provide valuable insights for effective thermal management in microelectronic devices.
Unlocking the potential of photoexcited molecular electron spins for room temperature quantum information processing
Authors: Chen Kuan-Cheng , Collauto Alberto , Rogers Ciarán J , Yu Shang , Oxborrow Mark , Attwood Max
Published: October 2024

Future information processing technologies like quantum memory devices have the potential to store and transfer quantum states to enable quantum computing and networking. A central consideration in practical applications for such devices is the nature of the light-matter interface which determines the storage state density and efficiency. Here, we employ an organic radical, α,γ-bisdiphenylene-β-phenylallyl doped into an o-terphenyl host to explore the potential for using tuneable and high-performance molecular media in microwave-based quantum applications. We demonstrate that this radical system exhibits millisecond-long spin-lattice relaxation and microsecond-long phase memory times at room temperature, while also having the capability to generate an oscillating spin-polarized state using a co-dissolved photo-activated tetraphenylporphyrin moiety, all enabled by using a viscous liquid host. This latest system builds upon collective wisdom from previous molecules-for-quantum literature by combining careful host matrix selection, with dynamical decoupling, and photoexcited triplet-radical spin polarisation to realise a versatile and robust quantum spin medium.
Building Eurorack Modules with PCBs
Authors: Edstrom Brent
Published: October 2024

This chapter discusses how to build Eurorack modules with custom printed circuit boards (PCBs). It introduces DipTrace, a popular PCB-design application that represents a good blend of power, ease of use, and flexible licensing options. Unlike protoboard projects that utilize wires to connect front-panel components to circuitry, PCB projects typically utilize pots, switches, jacks, and other components that are soldered directly to a PCB. The chapter then explains how to create schematics with PCBs. It then highlights how the project that illustrates many core concepts can provide a handy mixer, which is a useful addition to almost any Eurorack kit.
A Health Media Literacy Intervention Increases Skepticism of Both Inaccurate and Accurate Cancer News Among U.S. Adults
Authors: Lyons Benjamin , King Andy J , Kaphingst Kimberly A
Published: October 2024

Background

Inaccurate cancer news can have adverse effects on patients and families. One potential way to minimize this is through media literacy training—ideally, training tailored specifically to the evaluation of health-related media coverage.

Purpose

We test whether an abbreviated health-focused media literacy intervention improves accuracy discernment or sharing discernment for cancer news headlines and also examine how these outcomes compare to the effects of a generic media literacy intervention.

Methods

We employ a survey experiment conducted using a nationally representative sample of Americans (N = 1,200). Respondents were assigned to either a health-focused media literacy intervention, a previously tested generic media literacy intervention, or the control. They were also randomly assigned to rate either perceived accuracy of headlines or sharing intentions. Intervention effects on accurate and inaccurate headline ratings were tested using OLS regressions at the item-response level, with standard errors clustered on the respondent and with headline fixed effects.

Results

We find that the health-focused media literacy intervention increased skepticism of both inaccurate (a 5.6% decrease in endorsement, 95% CI [0.1%, 10.7%]) and accurate (a 7.6% decrease, 95% CI [2.4%, 12.8%]) news headlines, and accordingly did not improve discernment between the two. The health-focused media literacy intervention also did not significantly improve sharing discernment. Meanwhile, the generic media literacy intervention had little effect on perceived accuracy outcomes, but did significantly improve sharing discernment.

Conclusions

These results suggest further intervention development and refinement are needed before scaling up similarly targeted health information literacy tools, particularly focusing on building trust in legitimate sources and accurate content.