bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation of spacer-engineered stacked nanosheet tunnel FET with varying design attributes
Authors: Jain Garima , Sawhney Ravinder Singh , Kumar Ravinder 
Published: March 2024

Abstract
The stacked nanosheet field-effect transistors (SNS-FETs) are potential contenders for sub-7 nm technology. Device miniaturization leads to a larger off-state current and a higher subthreshold slope in SNS-FETs. Unlike SNS-FETs, the stacked nanosheet tunnelling field effect transistors (SNS-TFETs) function as switches in integrated circuits, featuring high performance and low power consumption. The endeavour aims to investigate how each design parameter optimises the switching characteristics of the SNS-TFET device. This paper examines various design attributes, such as different dielectric spacer materials, nanosheet width (NW), nanosheet thickness (NT), source doping, drain doping, etc. The Cogenda Visual TCAD serves as a tool for conducting device simulations. According to the simulation study, the use of a high-k hafnium dioxide (HfO2) spacer produces a higher switching ratio (

7.28
×

10

11

) and a lower subthreshold swing (20.303 mV/decade). Using either low-k or no spacers reduces the overall gate capacitance and unit frequency gain compared to high-k spacers. Upscaling the nanosheet width (10 to 50 nm) enhances the switching ratio by

1.11
×

10

1

and transconductance by 61.92%. Downscaling the nanosheet thickness (6 to 4 nm) at the optimized nanosheet width (50 nm) improves the switching ratio by 1.88. Increasing the gate length from 8 to 16 nm reduces the leakage current by

2.34
×

10

−
2

A and improves the switching ratio by

2.90
×

10

1

.

An increase in the source doping level from

1
×

10

20

to

5
×

10

20

cm−3 results in a

1.07
×

10

2

decrease in the switching ratio and a 2.48-fold increase in the subthreshold swing. Furthermore, the findings indicate that drain doping is crucial in determining ambipolar current. In SNS-TFET, ambipolar current reduces significantly when drain doping is

1
×

10

17

cm−3. Thus, the proposed work addresses the limitations of scaling and optimised design parameter characteristics for low-power nanoscale circuits.
Theoretical study on optoelectronic properties of layered In2O3 and Ga2O3
Authors: Lionel Chrislene , Das Shubham , Banik Diparnab , Koley S 
Published: March 2024

Abstract
Composite oxides have been indeed proved to be valuable materials in optoelectronic applications. The combination of indium oxide and gallium oxide and other materials can lead to enhanced optical and electronic properties, making them suitable for a variety of optoelectronic devices. Meticulous analysis of the various optical properties helped to draw conclusions about the heterostructure of Indium and Gallium oxide and its use as a suitable semiconducting material in the medium bandgap range. The density of states and the band structure have been obtained from the density functional theory calculations. Real frequency phonon density of states supports dynamical stability of the crystal structure. A favorable energy band gap is achieved in the visible region of the spectrum, indicating that this mixed oxide is well suited for optoelectronic devices such as LEDs and solar cells.
Magnetic soliton and breather interactions for the higher-order Heisenberg ferromagnetic equation via the iterative N-fold Darboux transformation
Authors: Liu Xue-Ke , Wen Xiao-Yong , Zhang Ting 
Published: March 2024

Abstract
This paper focuses on a higher-order Heisenberg ferromagnetic equation, which may describe the motion of the magnetic vector of isotropic ferromagnetism. The iterative N-fold Darboux transformation is first constructed to generate the dark and anti-dark magnetic solitons on the non-zero constant backgrounds, bright and dark breathers on the trigonometric function and non-zero constant backgrounds as well as breathers on the trigonometric function and vanishing backgrounds. We discover that the soliton structures of three different components can generate rotation with different constant seed solutions. Meanwhile, the trajectory curve and the direction of the magnetic vector are also discussed from the perspective of magnetism, we find that for constant seed solutions, the motion of the magnetic vector is limited to the hemisphere, while for trigonometric seed solutions, the motion of the magnetic vector can be distributed throughout the whole sphere. These novel phenomena may be helpful to understand the dynamics of the magnetic vector in the magnetic materials.
Complex pattern evolution of a two-dimensional space diffusion model of malware spread
Authors: Cheng Haokuan , Xiao Min , Lu Yunxiang , Bao Haibo , Rutkowski Leszek , Cao Jinde 
Published: March 2024

Abstract
In order to investigate the propagation mechanism of malware in cyber-physical systems (CPSs), the cross-diffusion in two-dimensional space is attempted to be introduced into a class of susceptible-infected (SI) malware propagation model depicted by partial differential equations (PDEs). Most of the traditional reaction-diffusion models of malware propagation only take into account the self-diffusion in one-dimensional space, but take less consideration of the cross-diffusion in two-dimensional space. This paper investigates the spatial diffusion behaviour of malware nodes spreading through physical devices. The formations of Turing patterns after homogeneous stationary instability triggered by Turing bifurcation are investigated by linear stability analysis and multiscale analysis methods. The conditions under the occurence of Hopf bifurcation and Turing bifurcation in the malware model are obtained. The amplitude equations are derived in the vicinity of the bifurcation point to explore the conditions for the formation of Turing patterns in two-dimensional space. And the corresponding patterns are obtained by varying the control parameters. It is shown that malicious virus nodes spread in different forms including hexagons, stripes and a mixture of the two. This paper will extend a new direction for the study of system security theory.
Testing multi-field inflation with LiteBIRD
Authors: Jinno Ryusuke , Kohri Kazunori , Moroi Takeo , Takahashi Tomo , Hazumi Masashi 
Published: March 2024

Abstract
We investigate expected constraints on the primordial tensor power spectrum from the future cosmic microwave background polarization experiment LiteBIRD as a test of multi-field inflation, where we specifically consider spectator models as representative examples. We argue that the measurements of the tensor-to-scalar ratio and the tensor spectral index, in combination with the constraints on the scalar spectral index from the Planck observation, are useful in testing multi-field inflation models. We also discuss implications for multi-field inflationary model building.
Non-Gaussianity in rapid-turn multi-field inflation
Authors: Iarygina Oksana , Marsh M.C. David , Salinas Gustavo 
Published: March 2024

Abstract
We show that theories of inflation with multiple, rapidly turning fields can generate large amounts of non-Gaussianity. We consider a general theory with two fields, an arbitrary field-space metric, and a potential that supports sustained, rapidly turning field trajectories. Our analysis accounts for non-zero field cross-correlation and does not fix the power spectra of curvature and isocurvature perturbations to be equal at horizon crossing. Using the δN formalism, we derive a novel, analytical formula for bispectrum generated from multi-field mixing on super-horizon scales.
Rapid-turn inflation can produce a bispectrum with several
potentially large contributions that are not necessarily of the local shape.
We exemplify the applicability of our
formula with a fully explicit model and show that the new contributions indeed can generate a large amplitude of local non-Gaussianity, f
NL
loc ∼ 𝒪(1). These results will be important when interpreting the outcomes of future observations.
Quantum coherence and entanglement under the influence of decoherence
Authors: Sun Wen-Yang , Ding A-Min , He Juan , Shi Jiadong , Wang Le , Xu Hui-Fang , Wang Dong , Ye Liu 
Published: March 2024

Abstract
In this work, we delve into the dynamic traits of the relative entropy of quantum coherence (REQC) as the quantum system interacts with the different noisy channels, drawing comparisons with entanglement (concurrence). The research results demonstrate the broader prevalence and stronger robustness of the REQC as opposed to concurrence. It’s worth noting that the bit flip channel cannot uphold a constant nonzero frozen the REQC, besides, the concurrence follows a pattern of temporary reduction to zero, followed by recovery after a certain time span. More importantly, the REQC maintains its presence consistently until reaching a critical threshold, whereas concurrence experiences completely attenuation to zero under the influence of phase damping and amplitude damping channels.
Defect production in tungsten under sub-threshold energy irradiation: role of hydrogen and surface effects
Authors: Huang Hao-Xuan , Li Yu-Hao , Li Jin-Liang , Ma Fang-Fei , Ren Qing-Yuan , Liu Li-Min , Zhou Hong-Bo , Lu Guang-Hong 
Published: March 2024

Abstract
Despite the low solubility of hydrogen isotopes (HIs) in tungsten (W), their concentration can reach up to ∼10 at.% after low-energy plasma irradiation. This is generally attributed to the vacancies that may accommodate excessive HIs. However, the kinetic energy of incident HIs transferred to W is far below the energy threshold to create a Frenkel pair, the underlying mechanism of defect production is still unclear. Here, we investigate the influence of H on the defect production in W using the molecular dynamic (MD) simulations. It is found that the threshold displacement energy (TDE) in bulk W slight decreases with the increasing of H concentration. This is due to the formation of H-vacancy complexes, which prevents the vacancy-interstitial recombination. More importantly, the H effects are significantly magnified in the surface region. On the one hand, the maximum kinetic energy transferred from 400 eV H to W can reach up to ∼21 eV due to the double-hit process, which is two times higher than that predicted by elastic collision model. On the other hand, the momentum transferred to W is completely random, including both the recoil direction upward and downward from the surface. Accordingly, the lowest TDE in W surface is only 15–21 eV at sub-surface layers with the depth of 6.7–11.1 Å, which is lower than the maximum kinetic energy transferred to W. Therefore, the low-energy HIs irradiation can create the defects in W surface directly. Our findings provide deep insight into defect production in W at sub-threshold energy and have wider implications for materials performance under low-energy ions irradiation.
Structural optimization of S-CO2 Brayton cycle compressor impeller based on evolutionary algorithm
Authors: Xie Liangtao , Yang Jianguo , Hu Nao , Fan Yu , Sun Sicong 
Published: March 2024

Abstract
As the critical components for marine low-speed diesel engine flue gas waste heat recovery (WHR) supercritical carbon dioxide (S-CO2) Brayton cycle system, the structure of the compressor impeller is optimized by the evolutionary algorithm (EA) based on the co-simulation of the CAESES, ANSYS CFX and Opti Slang. The law of impeller pressure ratio, efficiency and power consumption in S-CO2 Brayton cycle (SCBC) as a function of rotational speed, inlet temperature, pressure and impeller structural parameters are revealed, and the method of improving SCBC efficiency for marine low-speed diesel engine flue gas waste heat recovery is studied. The optimized impeller structure is greatly enhanced in aerodynamic performance and safety, and the isentropic efficiency is increased by 2.54%, the pressure ratio is increased by 35.64%, and the temperature rise is increased by only 4.6%. A 100kW S-CO2 compression cycle test bench was set up to verify the simulation-optimized impeller results. The final results show that the optimized impeller structure, aerodynamic performance and safety are greatly improved. It provides theoretical support for selecting and optimising compressor impellers for marine low-speed diesel engine flue gas waste heat recovery S-CO2 Brayton cycle.
Investigation on unsteady characteristics of flow separation in a supercritical carbon dioxide centrifugal compressor
Authors: Yang Zimu , Jiang Hongsheng , Zhuge Weilin , Qian Yuping , Zhang Yangjun 
Published: March 2024

Abstract
As one of the core components of supercritical carbon dioxide (S-CO2) closed Brayton cycle, the efficiency of S-CO2 centrifugal compressor plays a crucial role. Affected by the special thermophysical properties of S-CO2 fluid, the flow mechanism of S-CO2 centrifugal compressor is different from the centrifugal compressor of conventional fluid, such as air. Previous studies have found that the flow separation within the flow domain of this kind of compressor is easily to occur downstream the pressure surface. Many steady computational fluid dynamics (CFD) studies have been conducted on the S-CO2 centrifugal compressors, but few studies focused on the unsteady evolution of this flow separation. In this paper, the unsteady CFD simulation is carried out in the flow passage of a S-CO2 centrifugal compressor. The solution domain of CFD simulation includes compressor blades, diffuser and volute. The performance and the unsteady flow behavior of S-CO2 centrifugal compressor is obtained. Under low flow rate conditions, the flow separation on the pressure surface of the blade of S-CO2 centrifugal compressor is more likely to occur, causing the decrease of compressor performance. This flow separation has strong unsteady characteristics, which deteriorates several times during a rotation cycle, meanwhile the vortex shedding happens. At the time steps of vortex shedding, the pressure near the trailing edge of the impeller fluctuates greatly, indicating that this unsteady flow separation brings a large flow loss to the S-CO2 centrifugal compressor.
Numerical investigation on the flow resistance characteristics of balance block in the rotary compressor
Authors: Zeng Wang , Pan Xi , Xie Junlong 
Published: March 2024

Abstract
With the increasing demand for energy saving, the air conditioner with variable frequency becomes the mainstream of the market, which leads to a high requirement for the dynamic balance characteristics of the rotary compressor at variable speed conditions. The balance block is the key part in the eccentric shaft system to balance the rotational inertia force brought by the eccentric wheel, and its flow resistance during rotating process has a large impact on the power consumption. In this paper, CFD simulations will be carried out to study the flow characteristics of several different compressor balance blocks and the results can provide reference for the optimization design of the balance block in the rotary compressor.
A numerical study of clogging analysis in submersible drainage pump
Authors: Rakibuzzaman Md , Suh Sang-Ho , Song Kwang Chul , Song Kyung Hee , Zhou Ling 
Published: March 2024

Abstract
Erosion of material surface due to collisions with solid particles has become a challenge to several engineering fields. Therefore, it is necessary to effectively design radial flow pumps that mitigate the sediment particles’ clogging effect from the system performance. This study aims to analyse and identify the clogging development of a newly designed submersible pump using computational fluid dynamics (CFD) techniques. The particle trajectory was accounted Tabakoff–Grant erosion model for predicting the clogging impact. The experimental pump performance results obtained by this study were used to validate the numerical results of the submersible pump. Pump results revealed a good agreement between the two marks, especially the head of the pump was obtained at a flow rate of 0.165 m3/min. When considering the motor power factor of 0.78, the pump efficiency was found to be 46%, and the test result was well-matched. Also, for combined cavitation-erosion, the performance characteristics of erosion rate density increase linearly. At a flow rate of 0.16 m3/min, the erosion rate density of the original model was more significant than the revised model. Furthermore, compared to the original model significantly reduced the adverse clogging effects on the impeller blades of the revised model.
The effect of the impeller eccentricity on the hydrodynamic characteristics of a centrifugal pump
Authors: Fancheng Wanli , Ni Hengtai , Liu Jing 
Published: March 2024

Abstract
To explore the effect of impeller eccentricity caused by shaft parallel misalignment on the hydrodynamic characteristics of a centrifugal pump, a numerical simulation model based on computational fluid dynamics (CFD) is established. The SST k-ω turbulence model is used to describe the flow field in centrifugal pump. The eccentric motion of the impeller is described by the sliding mesh method (SMM). The results indicates that the nonuniformity and instability of flow field will be aggravated with the increment of impeller eccentricity, which then reduce the pump head and efficiency to a certain extent. The radial force exerted on the impeller is directly proportional to the eccentricity of the impeller. In addition, the impeller eccentricity has a significant impact on the peak rotation frequency of shaft frequency. This study can provide a numerical reference for eccentricity fault diagnosis and vibration control of centrifugal pump impellers to carry out optimal design and vibration reduction.
Numerical investigation on vortex dynamics characteristics of a large vertical centrifugal pump operating in the hump region under cavitation conditions
Authors: Yang Gang , Shen Xi , Zhang Desheng , Luo Wenhua , Meng Jia 
Published: March 2024

Abstract
The large vertical centrifugal pump (LVCP) is widely used in major hydraulic engineering such as cross-region water transfer. This paper focuses on the hydraulic stability of LVCP under extremely operating conditions. The transient numerical simulations of cavitation in LVCP in the hump region are conducted based on delayed detached eddy simulation coupled with a homogeneous cavitation model. The main research is the effect of cavitation on the flow pattern and the vortex dynamics of the LVCP under stall conditions. The results of the numerical investigations show that the variation of the pump performance parameters is consistent with the experimental data under cavitation conditions. Under deep stall conditions, the H drop due to cavitation in the pump can happen earlier. Under the critical cavitation of the stall condition, backflow vortex cavitation, sheet cavitation and separation vortex cavitation can be observed at the impeller inlet. The vortex structures generated at the cavitation tail can result in worse flow patterns in the impeller. The vortex dynamics analysis shows that severe cavitation in the impeller deteriorates the inlet conditions of the vaned diffuser and induces sheet cavitation at the LE of vanes. The cavitations in the vaned diffuser accelerate the production and development of stall vortices and result in increased flow instability. The research in this paper can be helpful to improve the operation stability of LVCP.
Analysis of internal flow characteristics of a multistage pump during start-up
Authors: Xia Yinling , Mao Jieyun , Li Guidong , Zhao Danhua , Zhang Jinfeng , Wang Peng 
Published: March 2024

Abstract
In order to study the transient characteristics during the startup process of a multi-stage pump, the Flowmaster software was used to obtain the rotating speed and flow characteristic curves of the pump under different valve openings, and analyze its internal flow and structural characteristics based on numerical simulation. The study results indicate that the time required for the flow to reach a steady state lags significantly behind the time required for the rotational speed to reach a stable state during the initial stage of pump start-up. By comparing the pressure distributions of a multistage pump under quasi-steady state and transient conditions, it can be seen that the internal flow field evolution of the pump under transient condition during the startup process lagged behind that under quasi-steady state condition, which makes using quasi-steady state laws were not suitable for describing the changes in transient flow field. The deformation law of the first-stage impeller under stable and start-up conditions was similar. The impact of increased flow rate on deformation was relatively weak and the difference in deformation values under different flow rates was relatively small under transient condition.
High-temperature molten salt circulating cold salt pump shaft system prestress response analysis research
Authors: Gao Xiongfa , Zhao Yang , Zhu Zhiyu , Zhang Desheng , Wang Daohong 
Published: March 2024

Abstract
To investigate the response characteristics of the rotor system in a high-temperature molten salt pump, a specific model of a cold salt pump was selected as the research object. The natural frequencies and mode shapes, critical speeds, and harmonic response analysis based on modal analysis of the rotor system with and without prestress were computed. The results indicate that with prestress, the natural frequencies of the rotor are higher compared to the rotor without prestress, and there is no clear pattern among the various vibration modes. The calculated critical speed for the second mode is much higher than the rotor’s operating speed. This suggests that the rotor system will not experience resonance at its operating speed, meeting design requirements and ensuring stable operation. When the rotor of the cold salt pump is subjected to unbalanced forces, vibrations occur in the x, y, and z directions. The region with the largest vibration amplitude is located at the fifth-stage impeller. At a frequency of 52 Hz, the corresponding harmonic response displacement reaches its maximum value, and this frequency remains unchanged with variations in the magnitude and position of the unbalanced force. Therefore, it is advisable to avoid operating the rotor system at the critical speeds corresponding to the first and second modes. Furthermore, the operating speed of the rotor system is much lower than the critical speeds corresponding to the first and second modes, so axial unbalanced forces generally do not affect the normal operation of the rotor system.
A computational fluid dynamic method for dense-phase carbon dioxide centrifugal pump
Authors: Han Kejia , Li Zhen , Ju Yaping , Du Zhenming , Liu Zhipeng , Wang Zhenwei , Zhang Chuhua 
Published: March 2024

Abstract
As an advanced approach for large-scale low-carbon utilization of fossil energy, the carbon capture, utilization and storage technology is a promising means to achieve the carbon-neutrality target by 2060. Among the most widely used approaches for carbon storage is the enhanced oil recovery technique, for which the centrifugal pump is used to inject high-pressure dense-phase carbon dioxide (CO2) into the stratum. This work focuses on real fluid effects and inter-stage matching deviation from the incompressibility assumption for a dense-phase CO2 centrifugal pump, of which the inlet condition is close to the fluid critical point. With a thermophysical-state table for CO2 based on the thermophysical-property database of the National Institute of Standards and Technology embedded into a computational fluid dynamics solver, a numerical simulation method for compressible dense-phase CO2 pumps is established. The developed method is validated in the 50kW main compressor for a supercritical CO2 cycle and then applied to the simulation of a multistage dense-phase CO2 pump designed for carbon storage. The stage with the most remarkable fluid compressibility is determined, which provides a priori basis for the follow-up design optimization of the pump. This work is of promising application prospect for design of advanced dense-phase fluid machinery.