Ultra-high Speed Research Articles

Numerical assessment on a hybrid axial throughflow cooling scheme applied to the thermal management of bump-type gas foil bearings

Axial throughflow cooling is a practical thermal management solution for gas foil bearings (GFBs) with ultrahigh rotational speeds and small bearing clearances. The present study conducted a numerical investigation to assess a hybrid axial-throughflow cooling design (both inner cooling flow passing through the hollow shaft and outer cooling flow passing through the rotor–stator gap) for a specific radial bump-type gas foil bearing using the fluid–solid coupled modelling methodology. First, the individual effects of each cooling flow (i.e., the outer cooling mode only and the inner cooling mode only) on the GFB thermal behaviours are directly compared under a fixed rotational speed of ω = 1 × 105 rpm with a preset eccentricity ratio of ε = 0.9. The outer cooling mode exhibited superior cooling efficiency compared with the inner cooling mode with the same cooling air usage, albeit at the cost of a significantly greater flow pressure drop. Second, the conjugate roles of the hybrid cooling flows on the GFB thermal behaviours are related to the total cooling air mass flow rate of mtotal = 10 kg/h. Nine flow distribution relationships were comparatively studied between the two cooling flows under the same preset static bearing load of F = 31 N, wherein the percentage of the outer cooling flow (mouter/mtotal) varied from 10 % to 90 %. The heat removal pathway of the outer cooling flow was found to be dominant. The outer cooling flow exhibited a heat removal proportion close to 60 % when its distribution percentage was 30 %. The results of a comprehensive performance evaluation that considered the peak temperature reduction and cooling air pressure drop suggest a favourable distribution percentage of the outer cooling flow in the range of 30–40 %.

Waveguide-shaped tuning fork for designing ultra-compact and ultra-high speed 4 × 2 photonic crystal encoder

Waveguide-shaped tuning fork for designing ultra-compact and ultra-high speed 4 × 2 photonic crystal encoder

Simulation analysis of detonation wave propagation in explosive with multiple initiation points by generalized Interpolation material point method

In the research of explosion shock theory and engineering application, the convergence of detonation waves can be realized by using multiple initiation points to utilize the detonation energy and pressure effectively. To study the propagation process of detonation wave and the distribution law of impact energy of the explosive with multiple initiation points, a detonation calculation model of the explosive with multiple initiation points is constructed using an improved material point method, namely the generalized interpolation material point (GIMP) method. Meanwhile, two-dimensional and three-dimensional numerical simulations are given on detonation wave propagation and convergence processes in explosives with multiple initiation points. The process of detonation wave formation and convergence is simulated by Wuji Particle Dynamics (WP-DYNA) software, and the dynamic changes of physical parameters such as detonation pressure, product density, and internal energy are analyzed in detail. To verify the accuracy of numerical simulation, corresponding explosive detonation experiments are carried out; the simulation results are compared with the ultra-high speed photoelectric framing photography and the aluminum ingot double detonating cord experiment. The results show that the generalized interpolation material point method has good stability and relatively high calculation accuracy when simulating explosive detonation waves. A robust numerical calculation tool can be provided for the practical application of explosive detonation.

Electrode materials optimize operating voltage and switching speed in micro/nano plasma ultrafast devices

Abstract The trade-off between ultrahigh speed and low operating voltage is a major challenge in the continuous improvement of modern electronics. Although micro/nano plasma devices have demonstrated the potential of picosecond switching speed and high output power, surpassing traditional electronic devices, versatile methods for optimizing the operating voltage and switching speed are highly desired. Here, an optimization scheme based on the work function of the electrode materials is reported, which reduces the operating voltage and improves the switching speed. Compared with traditional methods, such as narrowing gaps or distorting electric fields, this approach offers advantages such as reducing production costs, enhancing consistency, and improving tunability. The experimental results show that using silver as a low-work-function electrode material can reduce the operating voltage by 55% to 180 V and increase the switching speed by 58% to 7.1 V ps−1 compared to platinum, which is equivalent to a 71% reduction in gap size. In addition, the underlying working mechanisms and inherent advantages of the approach are demonstrated, providing new insights for the ultrahigh switching speed and low-power application of micro/nano plasma devices, such as high-speed communication and ultrafast electronics.

Development of a High-Speed Precision Ultrasonic-Assisted Spindle for Ultra-Precision Optical Mold Machining.

Ultrasonic vibration-assisted grinding is a critical method for machining ultra-hard optical molds. However, current ultrasonic-assisted grinding spindles, as essential foundational equipment, face limitations in maintaining ultra-high rotational speed, high precision, and a compact structure during ultrasonic operation. This study presents a novel ultra-precision ultrasonic-assisted high-speed aerostatic spindle for grinding ultra-hard optical molds, developed through theoretical calculations, FEM, and CFD simulations. The spindle features a simple and compact design (φ60 mm outer diameter × 194 mm length), operates at an ultrasonic frequency of 41.23 kHz, and is driven by an impulse turbine providing torque up to 50.4 N•mm, achieving speeds exceeding 40,000 r/min. Aerostatic bearings provide axial and radial load capacities of 89 N and 220 N, respectively. The results demonstrate that the proposed high-speed precision ultrasonic spindle exhibits both feasibility and potential for practical application.

A Method for Dynamic Kolsky Bar Compression at High Temperatures: Application to Ti-6Al-4V

Abstract An experimental apparatus for measuring the dynamic behavior of materials subjected to strain rates on the order of 10 $$^3$$ 3 s $$^{-1}$$ - 1 and temperatures up to 800°C with a unique triple actuation system is developed in this work. This system is based on the traditional Kolsky (or split-Hopkinson pressure) bar design, with the addition of an external furnace used to heat the specimen to the desired temperature. A synchronized triple pneumatic actuation system is used to control the motion and timing of the the sample, incident, and transmitted bars. The cold contact time (CCT), or the time during which the heated sample is in contact with the room temperature bars before compression, is measured experimentally and carefully controlled to minimize the development of a temperature gradient across the sample and avoid heating of the bars. Experiments are performed in conjunction with ultra high speed imaging and 2D digital image correlation (DIC), as well as high speed thermal imaging. To verify the viability of the proposed system, experiments were conducted on Ti-6Al-4V (wt.%) at temperatures from 25°C up to and 800°C at an average strain rate of approximately 1200 s $$^{-1}$$ - 1 .

Analysis of microcracking processes in microconcrete under confined compression utilising synchrotron-based ultra-high speed X-ray phase contrast imaging

In the present study, microconcrete (MC) samples were exposed to dynamic quasi-oedometric compression (QOC) tests and visualised in-situ by the means of MHz synchrotron X-ray phase-contrast imaging in the ESRF synchrotron in order to analyse the damage mechanisms governing the mechanical behaviour of concrete under high-strain-rate confined compression. To do so, small cylindrical samples were placed in polymeric confinement cell and dynamically compressed along their axial direction using SHPB (Split-Hopkinson Pressure Bar) set-up available in ID19 beamline in the European Synchrotron Radiation Facility (ESRF). The damage process was visualized with MHz X-ray phase-contrast imaging along with an ultra-high-speed camera operating at a recording frequency approximately 1 Mfps (million frames per second i.e., 880 ns interframe time). The axial stress and strain temporal profiles were obtained from standard Kolsky's (SHPB) data processing. In addition, data of radial stress and strain within the sample were deduced from non-linear analysis of the mechanical behaviour of the polycarbonate confining cell instrumented with a strain gauge. Finally, the onset and growth of microcracking observed from the equatorial zone of large spherical pores is correlated with deviatoric and pressure measurements showing how the pore collapse process develops during the applied mechanical loading.

Research on the dynamic variation law of the discontinuous characteristics of the curvic coupling of aero-engine rotors under working conditions

For the design of advanced aero-engine rotor systems under ultra-high rotational speeds, this paper undertakes a comprehensive investigation into the contact stiffness of curvic couplings, which are the key connection mechanism of modern aero-engine rotors, and explores the dynamic variations in the contact stiffness of curvic couplings under working conditions. Firstly, the impact of dynamic loads of aero-engine rotors under working conditions on the curvic coupling is studied; Then, the contact stiffness analytical model of curvic couplings considering three-dimensional geometric features is proposed with the effects of dynamic loads; Finally, based on the established stiffness model, the dynamic loss laws of contact stiffness of curvic couplings under different dynamic loads are investigated, and the established model is experimentally validated. The results show that the dynamic loss law of contact stiffness varies with different dynamic loads. In comparison to the contact stiffness under the static condition, dynamic loads significantly reduce the contact stiffness of curvic couplings under working conditions, which in turn leads to changes in the dynamic characteristics of the rotor with curvic couplings. For the safe integration of the discontinuous rotor system under ultra-high rotational speeds, it is essential to carefully design and regulate the operating speed, transmission torque, unbalanced mass, and preload.

ADRC Control of Ultra-High-Speed Electric Air Compressor Considering Excitation Observation

With the increasing power of fuel cells, ultra-high-speed electric air compressors (UHSEACs) have been widely used. However, due to the ultra-high speeds involved, UHSEACs face problems such as long speed adjustment times and large speed fluctuations. Compared to other control methods, Active Disturbance Rejection Control (ADRC) is well-suited for highly nonlinear systems like UHSEACs. The Extended State Observer (ESO), a key component of the ADRC, struggles to accurately observe high-frequency excitations. To address this, the first step is to add a cascaded structure to the ESO and design a Current State Extended State Observer (CS-ESO) to better observe the electromagnetic and load excitations in the UHSEAC. The second step involves designing the ADRC based on the CS-ESO and performing speed adjustment simulations. The third step is to build a UHSEAC experimental platform and a conduct speed adjustment experiment. The findings indicate that, compared to the Proportional Integral Derivative (PID) control, the ADRC with the ESO, and the Sliding Mode Control (SMC), the use of the ADRC with the CS-ESO results in a significant reduction in overshoot—by at least 760 RPM under load-increasing conditions and 140 RPM under load-reducing conditions. Furthermore, the speed regulation time is notably decreased by at least 0.2 s and 0.1 s under these respective conditions.

B-146 Unlocking the potential of large-cohort proteomics studies with the Orbitrap Astral mass platform

Abstract Background Large-cohort proteomics analysis using mass spectrometry is a powerful approach to discover and validate new biomarkers. In combination with clinical data and computational analysis, large-cohort proteomics study brings opportunities in improving early diagnosis, refining patient stratification, and predicting/monitoring treatment response. Yet, to achieve meaningful biological insights in large-cohort studies, robust, reproducible, and comprehensive proteome profiling in a high-throughput manner still remains challenging. Here, we use a high-resolution accurate mass (HRAM) Oribtrap Astral platform to enable high-quality and robust protein quantification across thousands of LC-MS/MS analyses. With a throughput of 100 samples/day, we can reproducibly profile ∼9000 proteins from human cell line and ∼800 proteins from undepleted plasma across multiple instruments and more than 10 consecutive days in a 24/7 operation mode. Methods Experiments were performed on multiple Orbitrap Astral mass spectrometers with and without FAIMS Pro interface. Chromatographic separations were performed using a trap/elute method on Vanquish Neo system at a 11-minute gradient and a flow rate of 1ul/min, resulting in a throughput of 100 samples/day. Undepleted plasma digest was analyzed in a 24/7 mode for > 1000 injections on each LC-MS/MS setup. In addition, HeLa digest as quality control (QC) was analyzed every 12hours. The Oribtrap Astral platform was operated in data-independent acquisition (DIA) mode using a full scan with m/z 380-980, and DIA MS/MS scans with an isolation window of 2Th. Resulting DIA raw files were automatically transferred and processed using Chimerys in a beta version of Proteome Discoverer software. Results Multiple LC-MS/MS systems were operated in DIA mode either with or without FAIMS Pro device in a 24/7 operation mode at a throughput of 100SPD. Undepleted plasma digest was analyzed with >1000 injections on each LC-MS/MS setup. To monitor the baseline performance, HeLa digest served as QC were analyzed periodically every 12 hours with 3 technical replicates each time. To effectively manage and analyze these thousands of data files generated, we developed an automated data transfer and analysis pipeline. Automatically, the resulting DIA raw data files were immediately transferred to a server, then processed by state-of-the-art intelligent search algorithm Chimerys. Benefiting from the ultra-high scan speed of up to 200Hz on the Orbitrap Astral mass spectrometer, a much narrower isolation window width of 2Th was applied in the DIA method, comparing to 10-20Th on the classic DIA method. As a result, ∼9000 proteins from HeLa digest and ∼800 proteins from undepleted plasma digest were identified within only a 11-minutes gradient, respectively. More than 80% of the plasma proteins were reproducibly identified and quantified from all the runs on each LC-MS/MS setup, indicating a great reproducibility from run-to-run longitudinally. Stable and robust peptide quantitation was observed by extracting peptides with high, medium, and low abundant across the runs. Importantly, QC showed no performance degradation throughout the entire study, indicating high robustness of the entire LC-MS/MS setup. Conclusions Orbitrap Astral mass platform can comprehensively analyze the proteome of >1000s of sample robustly and reproducibly in a high-throughput manner, addressing the needs in large-cohort studies.

Robust Electric-Field Control of Colossal Exchange Bias in CrI3 Homotrilayer.

Controlling exchange bias (EB) by electric fields is crucial for next-generation magnetic random access memories and spintronics with ultralow energy consumption and ultrahigh speed. Multiferroic heterostructures have been traditionally used to electrically control EB and interfacial ferromagnetism through weak/indirect coupling between ferromagnetic and ferroelectric films. However, three major bottlenecks (lattice mismatch, interface defects, and weak/indirect coupling in multiferroic heterostructures) remain, resulting in only a few tens of milli-tesla EB field. Here, this study reports a robust electric-field control recipe to dynamically tailor the EB effect in a pure CrI3 homotrilayer on a ferroelectric Y-doped HfO2 (HYO) substrate, and demonstrate a colossal and tunable EB field (HE) from -0.15 to +0.33 T, giving rise to an EB modulation of 0.48 T. The charge doping due to ferroelectric HYO film divides a homo-configuration of CrI3 homotrilayer into one antiferromagnetic (AFM) bilayer CrI3 and one ferromagnetic (FM) monolayer CrI3, favoring direct exchange coupling. The synergies of charge doping and electric field induce a transition of magnetic orders from AFM to FM phase in bilayer CrI3, which is also supported by first-principles calculations, leading to the robust electric control of colossal EB effect. The results therefore open numerous opportunities for exploring 2D spintronics, memories, and braininspired in-memory computing.

The Effect of Support Misalignment on Vibration Characteristics of Aero-Engine Rotor Systems under Ultra-High Operating Speeds

In order to ensure the vibration safety of rotor systems in the next generation of aero-engines and reduce the impact of misalignment faults, the effect of support misalignment on the vibration characteristics of rotor systems under ultra-high operating speeds is investigated in this paper. Firstly, an analytical excitation model of the rotor systems under ultra-high operating speeds is established, considering the impact of the support misalignment. Then, based on the model of the misaligned combined support system, the dynamic model of the flexible discontinuous rotor support system with the support misalignment is presented. Subsequently, based on the established model, the effects of support parameters and support misalignment amounts on the vibration characteristics of the rotor support system are analyzed. Finally, experimental validation of the research findings is conducted. The research result shows that the support misalignment increases the vibration response of the rotor, reduces the vibration reduction efficiency of the combined support system, and consequently decreases the vibration safety of the rotor support system.

Large eddy simulation of various EMBr effects on the fluid flow, heat transfer and solidification process in an ultra-high speed thin slab casting mould with multi-port SEN

Effective control of intense turbulence is a crucial challenge for achieving steady production with ultra-high casting speed in thin slab continuous casting. In thin slab casting process, specially designed multi-port submerged entry nozzle (SEN) with four outlets is utilised to ensure an ample supply of molten steel, necessitating the selection and optimisation of suitable Electromagnetic Braking (EMBr) equipment for steel jet control. This study established a comprehensive three-dimensional model of a funnel-type mould, employing a combined experimental-numerical approach to validate and investigate the flow, heat transfer, solidification and electromagnetic behaviour in the mould. The steel grade studied in the simulation is Q235B, and its physical properties were calculated based on its composition with a temperature range of 1450–1826 K. To analyse the influence of high casting speed on the flow and solidification behaviour in the mould, three casting speeds were selected for the study, which were 6, 7 and 8 m/min. The results indicate that the novel Bowl EMBr significantly suppressed the penetration of steel jet and thus enhanced the thickness and uniformity of the solidified shell. As the casting speed increases from 6 to 8 m/min, the solidified shell thickness at the mould exit decreases from 7.91 to 5.94 mm, with the stagnant growth region approaching the mould exit. This highlights the requirement to correspondingly increase EMBr strength under ultra-high casting speed condition to avoid remelting of the shell and the risk of molten steel leakage. The coupled mathematical model established in this study provides guidance for optimising EMBr structures and casting speed under special multi-port SEN conditions, offering recommendations for the rational control of flow, heat transfer and solidification process in the mould.

Effect of WC content on the microstructure and properties of AlCoCrFeNi2.1 eutectic high entropy alloy coating prepared by ultra-high speed laser cladding technology

AlCoCrFeNi2.1 eutectic high entropy alloy coating with different WC content were prepared on 304 stainless steel surface by ultra-high speed laser cladding technology. Microstructure, phase distribution, Microhardness, friction, and wear properties were analyzed to investigate the influence mechanism of WC on the properties of alloy coatings. The results indicate that the addition of WC results in refined crystalline strengthening. The decomposition of WC leads to the formation of W2C and Cr23C6, which contribute to solid solution strengthening and second-phase strengthening. With increasing WC content, a noticeable improvement in microhardness and wear resistance properties is observed.

PhotoSolver: A bidirectional photonic solver for systems of linear equations

Solving systems of linear equations is one of the most fundamental challenges in computing, with ubiquitous applications in science and engineering. Solving large-scale linear equations is particularly challenging, requiring tremendous computing expenses. However, conventional solvers in electronic digital computers face inevitable physical bottlenecks that hinder further advancements in electronic chips. Unlike the electronic architectures, optical computing harnesses the inherent advantages of lights, such as ultimately high speed, negligible energy consumption, and high parallelism, making optical architectures attractive sources for ultra-high speed analog computing. Especially, recent advances in integrated photonic circuits bring exciting new possibilities for high performance computing based on photonic chips. In this work, we propose a bidirectional PhotoSolver using the propagation of optical signals in different directions on a single integrated photonic chip to perform multiple operations in solving systems of linear equations, scalable to solve large-scale systems. Specifically, we propose an in situ approach to iteratively update solutions by performing the forward and backward propagations within a single photonic chip. Furthermore, we propose a partitioning approach to solve large-scale systems using arrays of photonic chips. Numerical experiments demonstrate these capabilities with representative systems of linear equations. By utilizing lights propagating in integrated photonic chips, our PhotoSolvers provide a promising computing architecture to solve large systems of linear equations, with potentials in wide computational applications.

Rapid generation of birefringent nanostructures by spatially and energy manipulated femtosecond lasers for ultra-high speed 5D optical recording exceeding MB/s.

In the current era of data explosion, developing a data storage method that combines longevity, large capacity, and fast read/writing capabilities has become imperative. A promising approach is the nanogratings-based 5D optical data storage, which is realized by femtosecond lasers processing of silica glass, with its extremely long storage lifetime and high-density storage capabilities. However, a significant limitation of nanogratings is that their formation relies on in-situ irradiation with tens to hundreds of femtosecond laser pulses. This limitation severely hinders the writing speed of storage techniques that rely on nanogratings. Addressing this challenge, our method, rooted in a deep understanding of the nanogratings evolution process, effectively reduces the pulse requirement for inducing a complete birefringent nanostructure to just three. By modulating the energies and focus depths of seeding and writing pulses, this method achieves control over the material environment and near-field enhancement in the focus region. Crucially, it circumvents the ascent process of nanovoids, a process traditionally necessitating more than 80% pulse number during nanogratings formation. This approach significantly boosts the recording speed of 5D optical data storage based on birefringent nanostructure, likely achieving speed exceeding megabytes per second (MB/s). Such a breakthrough facilitates the development of innovative practical applications utilizing nanogratings structures, including multi-dimensional optical data storage, microfluidics, waveguide, and geometric phase components.

Analysis of drilling response under ultra-high-speed diamond drilling: Theory and experiment

The ultra-high-speed diamond drilling (UHSDD) technology represents a groundbreaking and effective approach to deep hard rock drilling. This innovative method addresses the critical need for reduced weight on bit (WOB) while simultaneously achieving remarkable enhancements in drilling velocities. However, the absence of a comprehensive fundamental theory poses challenges, such as drill wear and inconsistent rock crushing efficiency. In this paper, the experimental data obtained from UHSDD was processed and analyzed by leveraging the drilling response model under standard rotational speeds (D-D model). The interface laws of diamond bit based on rate-relatedness were proposed. Notably, the depth of cut per revolution d of the bit is influenced by a complex interplay of rotational speed and weight on bit variables. A new variable Γ was introduced to measure the force required per revolution for d at ultra-high speeds. Within the proposed model framework, the quantitative information from drilling data was extracted, encompassing the wear state of the bit, drilling parameters, and rock properties. To validate the accuracy of the new model, a series of extensive laboratory experiments on the UHSDD test experimental platform was conducted. The reliability of the model was preliminary verified. The results of this study enhanced our understanding of the drilling response of UHSDD in practical drilling applications.

An Antiferromagnetic Neuromorphic Memory Based on Perpendicularly Magnetized CoO.

Antiferromagnets (AFMs) are ideal materials to boost neuromorphic computing toward the ultrahigh speed and ultracompact integration regime. However, developing a suitable AFM neuromorphic memory remains an aspirational but challenging goal. In this work, we construct such a memory based on the CoO/Pt heterostructure, in which the collinear insulating AFM CoO shows a strong perpendicular anisotropy facilitating its electrical readout and writing. Utilizing the unique nonlinear response and bipolar fading memory properties of the device, we demonstrate a multidimensional reservoir computing beyond the traditional binary paradigm. These results are expected to pave the way toward next-generation fast and massive neuromorphic computing.

Aerodynamic noise analysis of the skirting board under an ultra-high-speed train based on bidimensional empirical mode decomposition

ABSTRACT The grille located in the lower part of the train often forms a grille-cavity structure in the equipment bay’s surface. The issue of flow-induced sound of this structure becomes more significant at high speeds. In this study, we focus on a skirting board with a grille, that is simplified as a grille-cavity structure. We use DDES in combination with modal decomposition, to analyze the fluidization mechanism of the structure. The results indicate that the shear oscillation at the opening of the cavity is more pronounced at ultra-high speed. Moreover, it has been shown that both POD and BEMD can accurately separate and identify coherent structures in the flow field. BEMD has higher accuracy. And the flow is primarily dominated by low-frequency acoustic oscillation. Finally, when we compare three grille configurations (V, ᴖ), we find that the grille’s presence mitigates the cavity’s aerodynamic noise, especially when using a -shaped grille.

Design and implementation of dynamic balance in ultra-high speed IP network

Abstract Nowadays, with the rapid development of IP network service demand, network construction is also accelerating, IP network is expanding at a higher rate, and gradually moving toward ultra-high speed networks above 40G. In view of the problems of inconsistent IP packet order, random IP packet length and traffic burst brought by the application environment of high traffic, high bandwidth and high concurrency in ultra-high speed IP network, this paper introduces a kind of dynamic balance processing technology of ultra-high speed IP network based on information label. By optimizing the IP processing architecture, a two-level scheduling architecture of multi-board and multi-module is established, and VPN is established in ultra-high speed IP network by using dynamic balance processing technology and order preserving technology to realize high performance IP processing, so as to achieve ultra-high speed data transmission.