bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pressure-induced phase transition in cubic Yb2O3 and phase transition enthalpies
Authors: Jiang Sheng , Zhang Jichao , Wang Lingrui , Lin Chuanlong , Yan Shuai , Liu Jing , Li Aiguo , Tai Renzhong 
Published: September 2023

The high pressure structural evolution of cubic Yb2O3 has been studied using in situ synchrotron angle dispersive x-ray diffraction in combination with diamond anvil cell techniques up to 44.1 GPa. The XRD measurements revealed an irreversible reconstructive phase transition from cubic to monoclinic Yb2O3 at 11.2 GPa and extending up to 28.1 GPa with ∼8.1% volume collapse and a subsequent reversible displacive transition from monoclinic to hexagonal phase starting at 22.7 GPa. The monoclinic phase coexists with the hexagonal phase up to 44.1 GPa. After pressure releases, the hexagonal Yb2O3 reverts to the monoclinic structure. The second-order Birch–Murnaghan equation of state fit to the pressure–volume data yields a bulk modulus of 201 (4), 187 (6), and 200 (4) GPa for the cubic, monoclinic, and hexagonal phases, respectively. Furthermore, the effects of the hydrostatic pressure state on the diffraction patterns, bulk modulus, and onset transition pressure of Yb2O3 under high pressure have been discussed. It is concluded that the bulk modulus of the cubic Ln2O3 phase increases with decreasing cation radius due to lanthanide contraction. Another important work in this study is the determination of the enthalpies of the cubic to monoclinic and monoclinic to hexagonal phase transitions of Yb2O3 of 37.0 and 17.4 kJ/mol, respectively, based on the basic thermodynamic equations and using the onset transition pressures and corresponding volume changes obtained from high pressure XRD experiments.
Wideband image-reject RF channelization based on soliton microcombs (invited paper)
Authors: Ding Jiewen , Wu Yifan , Yang Huashan , Zhang Chao , Zhang Yifei , He Jijun , Zhu Dan , Pan Shilong 
Published: September 2023

Wideband radio frequency (RF) channelization is essential for the reception and detection of cross-band RF signals in various applications, including communications, radar, and spectrum sensing. However, digital channelizers are inefficient at performing RF channelization over a working bandwidth above 10 GHz. Meanwhile, current photonic RF channelizers face challenges in simultaneously considering a wideband, multi-channel, and a high crosstalk suppression ratio. In this work, we proposed and demonstrated a wideband image-reject RF channelization scheme based on integrated dual-soliton microcombs. The dual-soliton microcombs are used for RF spectral copies and heterodyne detection, respectively. Supported by image-reject mixers, the RF channelization is verified with an 8–37 GHz working bandwidth, a 1.2 GHz channel bandwidth, and 25 channels. The image suppression ratio is higher than 34 dB for single-tone signals and 20 dB for wideband signals. Our approach provides an innovative architecture of integrated photonic RF channelizers with high performance, which can benefit a wide range of RF applications by miniaturizing the systems.
Superior white electroluminescent devices using nitrogen-doped carbon dots/TiO2 nanorods heterostructures
Authors: Chakrabarty Poulomi , Ghorai Arup , Pal Sourabh , Adak Deepanjana , Roy Baidyanath , Ray Samit K , Mukherjee Rabibrata 
Published: September 2023

Abstract
Nitrogen-doped carbon dots (NCDs), exhibiting strong yellow emission in aqueous solution and solid matrices, have been utilized for fabricating heterostructure white electroluminescence devices. These devices consist of nitrogen-doped carbon dots as an emissive layer sandwiched between an organic hole transport layer (PEDOT:PSS) and an array of rutile TiO2 nanorods, acting as an electron transport layer. Under an applied forward bias of 5 V, the device exhibits broadband electroluminescence covering the wavelength range of 390–900 nm, resulting in pure white light emission characteristics at room temperature. The result demonstrates the successful fabrication of all solution-processed, low-cost, eco-friendly NCDs-based LEDs with CIE (Commission Internationale d’Éclairage) coordinate of (0.31, 0.34) and color rendering index (CRI) > 90, which are close to ideal white light emission characteristics. The device functionalities are achieved based on defect-related NIR emission from TiO2 nanorods array and visible emission from nitrogen-doped carbon dots. This result paves a new opportunity to develop low-cost, solution-processed nitrogen-doped carbon dots based on warm White light emitting diodes with high CRI for large-area display and lighting applications.
Calculation and study for the growth process and electrical characteristics of the conductive filament in nanoscale resistance memory under current-driven mode
Authors: Ke Qing , Dai Yuehua 
Published: September 2023

Abstract
After investigating the behavior of ions during the growth of conductive filaments, we suggested a model for the growth process and electrical characteristics of the conductive filament under current-driven mode. In this model, the ionic displacement equation is derived by Arrhenius law, and a differential equation for the conductive filament growth has been established. We have also proved that the dielectric layer with the leakage current under current-driven mode can be equivalent to a parallel plate capacitor, which has a the equivalent dielectric constant. Consequently, the forming/set time of the device is gotten. At the same time, the kinetics process of ion motion is analyzed in detail, so that many microscopic parameters of the ion motion, such as the height of the potential barrier, the jump step, mobility and diffusion coefficient, can be obtained. Due to divalent and monovalent copper ions all participate in conduction, an equivalent copper ion Cuz+ is used for replacing both Cu+ and Cu2+, solving the computational complexity problem caused by multivalent metal ions. Finally, an equivalent circuit is proposed to calculate output voltage versus time characteristic. The calculation results of the model are consistent with experimental data.
Sub-second whole brain T2 mapping via multiband SENSE multiple overlapping-echo detachment imaging and deep learning
Authors: Li Simin , Kang Taishan , Wu Jian , Chen Weikun , Lin Qing , Wu Zhigang , Wang Jiazheng , Cai Congbo , Cai Shuhui 
Published: September 2023

Abstract

Objective. Most quantitative magnetic resonance imaging (qMRI) methods are time-consuming. Multiple overlapping-echo detachment (MOLED) imaging can achieve quantitative parametric mapping of a single slice within around one hundred milliseconds. Nevertheless, imaging the whole brain, which involves multiple slices, still takes a few seconds. To further accelerate qMRI, we introduce multiband SENSE (MB-SENSE) technology to MOLED to realize simultaneous multi-slice T2 mapping. Approach. The multiband MOLED (MB-MOLED) pulse sequence was carried out to acquire raw overlapping-echo signals, and deep learning was utilized to reconstruct T2 maps. To address the issue of image quality degradation due to a high multiband factor MB, a plug-and-play (PnP) algorithm with prior denoisers (DRUNet) was applied. U-Net was used for T2 map reconstruction. Numerical simulations, water phantom experiments and human brain experiments were conducted to validate our proposed approach. Main results. Numerical simulations show that PnP algorithm effectively improved the quality of reconstructed T2 maps at low signal-to-noise ratios. Water phantom experiments indicate that MB-MOLED inherited the advantages of MOLED and its results were in good agreement with the results of reference method. In vivo experiments for MB = 1, 2, 4 without the PnP algorithm, and 4 with PnP algorithm indicate that the use of PnP algorithm improved the quality of reconstructed T2 maps at a high MB. For the first time, with MB = 4, T2 mapping of the whole brain was achieved within 600 ms. Significance. MOLED and MB-SENSE can be combined effectively. This method enables sub-second T2 mapping of the whole brain. The PnP algorithm can improve the quality of reconstructed T2 maps. The novel approach shows significant promise in applications necessitating high temporal resolution, such as functional and dynamic qMRI.
Constraining quadratic f(R) gravity from astrophysical observations of the pulsar J0704+6620
Authors: Nashed G.G.L. , El Hanafy Waleed 
Published: September 2023

Abstract
We apply quadratic f(R) = R + ϵR
2 field equations, where ϵ has a dimension [L2], to static spherical stellar model. We assume the interior configuration is determined by Krori-Barua ansatz and additionally the fluid is anisotropic. Using the astrophysical measurements of the pulsar PSR J0740+6620 as inferred by NICER and XMM observations, we determine ϵ ≈ ± 3 km2. We show that the model can provide a stable configuration of the pulsar PSR J0740+6620 in both geometrical and physical sectors. We show that the Krori-Barua ansatz within f(R) quadratic gravity provides semi-analytical relations between radial, pr
, and tangential, pt
, pressures and density ρ which can be expressed as pr
≈ vr

2 (ρ-ρ
1) and pr
≈ vt

2 (ρ-ρ
2), where vr
(vt
) is the sound speed in radial (tangential) direction, ρ
1 = ρs
(surface density) and ρ
2 are completely determined in terms of the model parameters. These relations are in agreement with the best-fit equations of state as obtained in the present study. We further put the upper limit on the compactness, C = 2GMRs

-1
c
-2, which satisfies the f(R) modified Buchdahl limit. Remarkably, the quadratic f(R) gravity with negative ϵ naturally restricts the maximum compactness to values lower than Buchdahl limit, unlike the GR or f(R) gravity with positive ϵ where the compactness can arbitrarily approach the black hole limit C → 1. The model predicts a core density a few times the saturation nuclear density ρ
nuc = 2.7 × 1014 g/cm3, and a surface density ρs
> ρnuc
. We provide the mass-radius diagram corresponding to the obtained boundary density which has been shown to be in agreement with other observations.
Modelling and motion characteristics of a new multistage lead screw telescopic mechanism
Authors: Gao Xiaohui , Feng Zhipeng , Tong Saisai , Liu Yongguang 
Published: September 2023

Abstract
This paper presents a novel multistage electric telescopic mechanism. The mechanism is composed of multistage lead screw mechanism and multistage telescopic sleeve mechanism. It has the advantages of large stroke, large load and anti-sticking. Moreover, it has superior lateral bearing capacity and can be used in both transverse and longitudinal heavy load conditions. The force of the mechanism is analysed and the motion principle of the mechanism is expounded. Its mathematical model is established and its motion characteristics are studied. The speed, displacement and force data of the lead screw are analysed to verify its reliability and stability. The appropriate design parameters are obtained through the combination of experiment and simulation.
Modular design and simulation analysis of truss robot based on spatial bars structure
Authors: Wang Leilei , Gao Peng , Che Lei 
Published: September 2023

Abstract
For industrial applications, truss robots can perform mutipleoperations, such as transporting objects and handling tools independently, but face the challenges of inconvenient disassembly and non-recyclability. Therefore, a truss robot load-bearing module based on a spatial bar structure is designed, which consists of truss bars and connectors. Ansys Workbench is used for the static analysis of the truss robot beam. The results show that the maximum stress of the truss robot beam is 32.46 MPa and the maximum deformation is 1.1 mm under the load of 12,000 N. The maximum stress of the beam is significantly small than the yield limit of the material and the deformation is small, which meets the requirements of structural strength and load stability of the truss robot. Based on the mode analysis of the truss robot, the inherent vibration and frequency of the truss robot are extracted, providing a reference basis for the stability control of the truss robot. The modular truss robot has mutiple advantages, including the large span, high load capacity and assembly flexibility.
Finite element simulation study on cutting coal and rock by cutting head of roadheader
Authors: Liang Jianan , Tian Muqin , Huo Pengfei 
Published: September 2023

AbstractIn order to improve the cutting efficiency of the roadheader and address the challenge of monitoring the load of the cutting head and pick, a load simulation method was proposed using ABAQUS finite element software to simulate the cutting head at different cutting depths under various cutting conditions. According to the coal cutting test, a finite element simulation model was developed using Drucker-Prager as the constitutive model of coal to simulate the conical pick cutting of coal. The results of the finite element analysis were compared with the cutting test results, and the reliability of the former was confirmed. The study further involved establishing a model of cutting coal with different depths under various working conditions, and the torque waveform was obtained through finite element simulation. MATLAB was employed to program the theoretical formula, the theoretical waveforms of the force and torque of the cutting head were obtained. Additionally, the mean value of the cutting force of each pick in the finite element simulation results under different working conditions was statistically analyzed, and its distribution law was obtained. The results showed that the finite element simulation results were in good consistency with the theoretical calculation results, indicating that the simulation method was both reasonable and feasible for simulating the coal cutting process. Finite element simulation combined with theoretical calculation can be used in the stability control of cutting head dynamic load, and provide a basis for improving cutting efficiency.
Low-order isotropic spatial resolution characteristics of the viscous terms for LES analysis on iso/anisotropic steady turbulent flows
Authors: Hirabayashi Riku , Suzuki Hiroki , Mochizuki Shinsuke 
Published: September 2023

Abstract
This study aims to clarify the effect of reducing the isotropic spatial resolution on the turbulence field obtained in the Large Eddy Simulation (LES). Here, isotropic or anisotropic steady turbulence is analysed in this LES. A linear forcing method is used to generate these steady turbulent flows. Although the spatial resolution can be enhanced by increasing the number of spatial grid points or by using higher-order discrete forms, the isotropic resolution is only sometimes maintained. This viewpoint is expected to be particularly evident in the present study, especially in the LES analysis of wall turbulence. The present study focuses mainly on the spatial resolution of the viscous terms, where the spatial resolution can be varied while maintaining isotropy. Here, the discretisation accuracy order of the viscous terms was set from second to eighth order. In this study, the discretisation accuracy order of the convection terms is also varied. As shown in this study, the effect of the viscous term on the turbulence fields is larger than that of the discretisation accuracy order of the convection terms. There is a difference in the characteristics of the turbulence field obtained when the discretisation accuracy of the viscosity terms is of second and fourth or higher order.
Research on operation characteristics and control strategy of hybrid multi-feed HVDC system
Authors: Wang Ting , Hu Xinyang , Zhang Longen , Ye Pangqi 
Published: September 2023

Abstract
Flexible DC transmission technology based on voltage source converter (VSC-HVDC) and high voltage DC transmission technology based on grid commutation converter (LCC-HVDC) have complementary characteristics, so the hybrid DC technology combined with LCC-HVDC and VSC-HVDC can make them complement each other and become the development trend of power grid technology in the future. In the existing hybrid multi-infeed DC system, conventional DC transmission (LCC-HVDC) and flexible DC transmission (VSC-HVDC) operate independently and are not coordinated with each other, but there is a blank in the research on the protection coordination relationship between VSC/LCC parallel DC hybrid system and its near area AC system. Therefore, it is necessary to theoretically analyse and study the operation characteristics, control strategy and protection coordination relationship between near-area AC systems of hybrid multi-infeed HVDC systems. Due to the limited space, this paper mainly analyses the operation characteristics and control strategy of hybrid multi-infeed HVDC system, and verifies the correctness of the theory through simulation research. In the next step, the corresponding protection is configured in the above simulation model, and the protection adaptability analysis and protection optimization scheme of hybrid multi-infeed HVDC system are obtained.
Daily load prediction study on SCASL and BiGRU models
Authors: Li Qiaosen , Chen Li , Wang Changyi , Zhang Xiang , Zhao Jing 
Published: September 2023

Abstract
In the short-term power load prediction, the environmental uncertainty will have an impact on the prediction accuracy and increase the complexity of the prediction. To deal with this problem, the paper proposes a bidirectional gated recurrent unit (BiGRU) network model for and sine cosine optimization algorithm with self-learning strategy and Levy flight (SCASL). With real power load data as a data set, high correlation parameters are selected through the Pearson correlation coefficient analysis as input, using the SCASL algorithm and nonlinear weight factor. Finally, the key time points in capturing the historical information of the load changes are established according to the optimization parameters, and BiGRU model is used to learn to predict its accuracy. The experimental results show that the MAPE (Mean Absolute Percentage Error) and RMSE (Root Mean Square Error) of BiGRU model are better than the comparison model gated recurrent unit (GRU) network model. The final results show that the prediction accuracy of the power load system has been significantly improved.
Real-time measurement and compensation based on iGPS for industrial robotic pose accuracy
Authors: Shi Feng , Sun Nianjun , Du Zhaocai , Liu Liming 
Published: September 2023

Abstract
In order to satisfy the requirements of industrial robotic pose accuracy in the operation process, measurement and compensation methods based on iGPS (indoor Global Positioning System) are proposed. An iGPS measuring network is established by solving transformation relations between robotic coordinates and iGPS coordinate, setting up measuring field and calibrating external parameters of transmitters. According to the measured values of iGPS, pose accuracies are calculated, and robotic poses are compensated by modifying command pose and secondary motion fine-tuning respectively. Experiments are designed to verify the measurement and compensation methods. The robotic poses of pre and post compensation are depicted based on 30 successive motion cycles. The pose accuracies are calculated and the effects of the two compensation methods are compared. Experimental results show that the robotic pose accuracies are greatly improved by using the proposed methods, and the real-time compensation method of secondary motion fine-tuning has better compensation effect, which proves the feasibility and effectiveness of the real-time measurement and compensation method based on iGPS.
Development and application research of startup failure and operation failure model of emergency diesel generator in nuclear power plants
Authors: Yang Xiaohu , Qing Chen , Yu Na , Zhang Yanpeng , Cheng Bin 
Published: September 2023

Abstract
In order to fully grasp the law of startup failure and operation failure of emergency diesel generator in nuclear power plants, this paper first presents the development method of integrated fault model for emergency diesel generator startup failure and operation failure on the basis of fully integrating the existing mature fault tree analysis methods. Then, taking a certain type of Emergency diesel generator as an example, a complete startup failure and operation failure model was developed, and qualitative analysis and quantitative evaluation were carried out on the basis of the model, which verified the accuracy and applicability of the model development method. Finally, this paper puts forward the qualitative analysis and quantitative evaluation results based on model, which are directly used in the basic application scheme of equipment safeguard measures and the advanced application scheme of dynamic risk assessment and long-term trend monitoring of emergency diesel generator sets based on model + data driven by emergency diesel generator sets. Through the advanced application solution, users can identify dynamic high-risk defects and long-term reliability management weaknesses in advance, and formulate effective short-term fault elimination and long-term fault prevention measures in time to avoid the consequences of startup failure and operation failure. The above research results have important practical significance for the continuous improvement of the startup reliability and operation reliability of emergency diesel generator in nuclear power plants.
Thermal simulation analysis of power module of combined converter for metro vehicle
Authors: Zhang Junfeng , Chen Yutong , Zhang Liwei 
Published: September 2023

Abstract
In order to reduce the occupancy space and equipment cost of the on-board converter, a combined traction-auxiliary converter for subway vehicles is proposed in this paper. The power loss of the main traction converter module (MCM) and the auxiliary converter module (ACM) was calculated according to the speed and power variation of the vehicle running between five consecutive stations, and the flow rate of cooling air was calculated through the heat balance theory. The air volume of MCM and ACM and the plate temperature of the radiator are analysed by step method. Then, according to the instantaneous maximum temperature of the radiator obtained by simulation and the thermal parameters of the IGBT module, the junction temperature of the IGBT and diode chips is calculated by means of the junction temperature equivalent circuit. The results show that the plate temperature of the heat sink and junction temperature meet the design requirements. The design and thermal simulation method in this paper provide theoretical reference for the design of railway vehicle converters.