Ultrafast Method Research Articles

Ultrafast synthesis and luminescence properties of rare earth orthoniobates RENbO4 (RE = La, Eu, Gd, Yb, Lu)

Rare earth orthoniobates (RENbO4) are one kind of important functional materials due to its applications in solid-state phosphors, thermal barrier coatings, and microwave dielectric ceramics. The synthesis of rare earth niobates often needs high reaction temperatures (1300 °C–1700 °C) and long processing times (from hours to tens of hours) in solid-state reactions, which can increase the study time of the relationship between structure and properties. In this work, we used ultrafast high-temperature sintering method to synthesize RENbO4 (RE = La, Eu, Gd, Yb, Lu), and found specific structure and properties in these materials obtained with specific synthetic techniques. Based on the electronegativity scale, the charge transfer energy of lanthanide ions in the YNbO4 crystal was calculated. The rapid synthesis of RENbO4 in a vacuum atmosphere generated more oxygen vacancies, and the structures of [REO8] and [NbO6] were distorted. The shortening of the fluorescence lifetime of LaNbO4 and EuNbO4 was related to the formation of self-trapped excitons facilitated by lattice distortion. The emission peak of LuNbO4 at about 530 nm is attributed to the oxygen vacancy in the niobate group. The reported synthetic methods can provide a fast materials screening route for high melting point inorganic materials.

High-speed shearing: An ultra-fast internal energy accumulation method for nucleation of SnZnO in photocatalysis

Zinc oxide (ZnO) nanoparticles and their derivatives, appreciated for their cost-effectiveness, simplicity in synthesis, and versatile applications, have garnered considerable attention. However, unraveling the nucleation and growth mechanisms of ZnO nanoparticles remains a formidable challenge. By comparing the magnetic stirring synthesis (MSS) and high-speed shearing (HSS) methods, we conducted time-dependent calculations of pressure and velocity at various positions in the solution. Under the powerful shearing force, which is the key route to accumulate internal energy (Ein), molecules could achieve at most 174 eV Ein in HSS instead of 0.81 eV Ein in MSS. Molecules could obtain enough energy for nucleation in just 1.03 μs. HSS, utilizing a high-speed rotor for robust shear forces, not only modifies nucleation patterns but also facilitates effective mixing in multi-element systems. SnxZn1−xO1+x nanoparticles prepared through HSS display uniform size, markedly reduced agglomeration, homogeneous element distribution, and a more pronounced bandgap change, causing a decrease in photocatalytic activity to the original 11.2 %.

Spectator Exciton Effects in Nanocrystals III: Unveiling the Stimulated Emission Cross Section in Quantum Confined CsPbBr3 Nanocrystals.

Quantifying stimulated emission in semiconductor nanocrystals (NCs) remains challenging due to masking of its effects on pump-probe spectra by excited state absorption and ground state bleaching signals. The absence of this defining photophysical parameter in turn impedes assignment of band edge electronic structure in many of these important fluorophores. Here we employ a generally applicable 3-pulse ultrafast spectroscopic method coined the "Spectator Exciton" (SX) approach to measure stimulated-emission efficiency in quantum confined inorganic perovskite CsPbBr3 NCs, the band edge electronic structure of which is the subject of lively ongoing debate. Our results show that in 5-6 nm CsPbBr3 NCs, a single exciton bleaches more than half of the intense band edge absorption band, while the cross section for stimulated emission from the same state is nearly 6 times weaker. Discussion of these findings in light of several recent electronic structure models for this material proves them unable to simultaneously explain both measures, proving the importance of this new input to resolving this debate. Along with femtosecond time-resolved photoluminescence measurements on the same sample, SX results also verify that biexciton interaction energy is intensely attractive with a magnitude of ∼80 meV. In light of this observation, our previous suggestion that biexciton interaction is repulsive is reassigned to hot phonon induced slowdown of carrier relaxation leading to direct Auger recombination from an excited state. The mechanism behind the extreme slowing of carrier cooling after several stages of exciton recombination remains to be determined.

Development and validation of an ultrafast method of quantification of rivaroxaban in human serum using laser diode thermal desorption coupled to triple quadrupole mass spectrometry.

Rivaroxaban is an anticoagulant prescribed to patients who are at risk of medical conditions such as deep-vein thrombosis, pulmonary embolisms, and strokes caused by blood clots. The administration of this drug is monitored to adjust the dosage and evaluate patients' blood concentration. Rapid quantification of this drug in plasma could make it possible to ensure that the dose present in the blood of patients does not represent a danger for the medical intervention to be carried out. Liquid chromatography-tandem mass spectrometry is usually employed to quantify rivaroxaban in blood, plasma, and serum. Here, an alternative method of analysis based on laser diode thermal desorption-triple quadrupole mass spectrometry (LDTD-QqQMS) was developed and comprehensively validated. This new method allows the quantification of rivaroxaban in less than 13 s from sample to sample. The extraction of rivaroxaban in human serum was done by a salting-out liquid-liquid extraction with acetonitrile and a saturated sodium chloride solution. The proposed method allows the quantification of rivaroxaban in less than 13 s from sample to sample. During validation, all criteria were respected. The accuracy was <15% of the nominal value, the precision was <15%CV, and the recovery was ≥89.9%. There were no observed carryover or matrix effects. Analysis of the extracted samples established the stability of dry (24 h) and wet samples (1week) when samples cannot be analyzed immediately, a considerable advantage in a clinical setting. This method improves sample throughput by more than 1200% compared to liquid chromatography-tandem mass spectrometry methods of analysis of rivaroxaban and decreases analysis costs by reducing solvent consumption and instrument time.

A novel method for ultra-fast determination of phenolics with performance comparable to UPLC/DAD: Method development and validation on analysis of seedless table grapes

Grapes are well-known for the rich content of phenolics with benefits for human health. The reliable identification of phenolics in grapes is essential to explore the related bioactivity, highlighting the value of the grape source. In this work, an ultra-fast method for determining phenolic compounds in HPLC-DAD using a Rapid Resolution High Throughput-RRHT column (RP-C18 4.6 ×50 mm, 1.8 µm) was developed and validated and nine seedless table grapes produced in the São Francisco Valley, Brazil were analyzed. The method showed good sensitivity (LOD≤ 0.65 mg/L and LOQ< 1.12 mg/L), high linearity (R2 > 0.998), selectivity, precision (CV%< 6.82). The recovery (81.5–105.6 %) was adequate for the desired purpose. A total of 41 phenolics were separated in 20 min, rending a resolution equivalent to UPLC-DAD. Thirty-four phenolics were quantified in grapes, including eight phenolic acids, two stilbenes, one phenolic aldehyde, three isoflavones, four flavanols, three proanthocyanidins, five flavonols, and eight anthocyanins. Patented grapes presented a high content of mono glucoside anthocyanins. Brazilian registered grapes presented high anthocyanin content and the presence of 3,5-diglucoside anthocyanins. The validated method is an alternative for rapid identification of phenolics and maybe useful to stablish procedures for identifying compounds in determining the markers in fruit.

Ultrafast Construction of Interfacial Akaganéite FeOOH Phase to Enable the Long‐Term Stability of Nickel‐Iron Hydroxides for Seawater Splitting at Ampere‐Level Current Density

AbstractNiFe‐based hydroxides are well‐established as efficient electrocatalysts for the oxygen evolution reaction (OER) in alkaline purified water. However, they usually degrade rapidly in seawater electrolysis because of concentrated Cl− anions in seawater. In this work, a facile approach utilizing an ultrafast dipping method is presented to fabricate durable and scalable NiFe hydroxides, enhanced by interfacial akaganéite FeOOH for seawater splitting. This study reveals significantly improved electrocatalytic stability of NiFe hydroxides at an ampere‐level current density of 1000 mA cm−2 for 100 h in alkaline seawater. It is realized by the formed FeOOH in a specific akaganéite phase whose lattice tunnels are well filled by intrinsic Cl− anions, that serve to electrostatically repel corrosive chlorides in electrolyte. This anionic design also provides superior corrosion protection for other active metal‐based OER electrocatalysts when deployed in alkaline purified water and allows for facile scaling up of the anode, facilitating the practical utilization for seawater electrolysis.

Ultrafast gelation of multifunctional β-cyclodextrin based hydrogel electrolyte for self-healing supercapacitor

The increasing attention towards flexible supercapacitors with self-healing ability can be attributed to their capacity to endure deformation and damage. However, the development of self-healing and adhesive hydrogel electrolytes, which serve as substrate materials for supercapacitors, remains a challenge. This work reports an ultrafast gelation method for fabricating multifunctional PAA-SL-CD hydrogels with ultrahigh stretchability, fast self-healing ability, superior adhesion, and high ionic conductivity (6.15 S/m). These excellent properties can be attributed to the hydrogen bonding between β-CD, the catechol groups and PAA chains, as well as metal-catechol coordination, metal-carboxyl coordination, and the unique truncated cone structure of the β-CD molecule. A flexible supercapacitor, fabricated using PAA-SL-CD hydrogel as electrolyte, demonstrates high areal specific capacitance (950 mF/cm2) and a capacitance retention rate of 76.3 % even after five cutting and healing cycles. With the well-designed adhesion of the hydrogel electrolyte, the device exhibits impressive specific capacitance retention after cyclic bending. Notably, a series supercapacitor retains the ability to power a clock for 28 min.

SURG-01. ULTRA-FAST DEEP-LEARNED CNS TUMOR CLASSIFICATION USING STURGEON; THE IMPACT ON STRATEGY FOR THE PEDIATRIC NEUROSURGEON

Abstract INTRODUCTION Central nervous system tumors still represent one of the most challenging fields to create curation in pediatric oncology. The primary treatment always starts with a neurosurgical intervention to obtain tumor tissue for diagnosis. In most cases this intervention is a maximal safe resection of the tumor. The oncological prognostic value of extent of resection is determined by the precise molecular diagnosis and per-operative ultra-fast molecular classification of central nervous tissue provides the neurosurgeon relevant information for choosing the right strategy. This per-operative molecular diagnosis determines the balance between the need of radicality versus the prevention of neurological morbidity in the individual patient. We shall report on our neurosurgical experiences with the per-operative use of Sturgeon in our national practice of pediatric neuro-oncology in the Netherlands. METHODS The ultra-fast AI-based nanopore sequencing method, Sturgeon, has been implemented as per-operative diagnostic in most neurosurgical tumor resections in our center (1). An overview of our nanopore sequencing pipe- and timeline will be presented and its impact on neurosurgical strategies will be shared. RESULTS Reliable and accurate diagnoses can be obtained within 40 minutes after starting sequencing in 45 out of 50 retrospectively sequenced samples (while abstaining from diagnosis of the other 5 samples). The implementation in real time surgery results in a turnaround time between taking out sample material to diagnosis in less than 90 minutes. The most important result is that there is a high sensitivity and virtually no false positives since it is refraining from diagnosis when there is too much uncertainty. Several illustrative cases with impact on the neurosurgical strategy have been collected. CONCLUSION Ultra-fast deep-learning CNS tumor classification using Sturgeon is feasible. Results of per-operative implementation illustrate the impact on neurosurgical strategy. 1. Ultra-fast deep-learned CNS tumour classification during surgery. Vermeulen C et al. Nature. 2023 Oct;622(7984):842-849.

Ultrafast Solid-Phase Oxidation of Aldehydes to Carboxylic Acids by Atmosphseric Plasma Treatment.

Although atmospheric plasma treatment is an industrially widespread, scalable, and environmentally friendly method, it has been generally used for surface modification, decontamination, or sterilization. In this paper, a novel, sustainable, green, and ultrafast oxidation method is described for aldehydes on a preparative thin-layer chromatographic plate as a solid support. The plasma treatment has proven to be suitable for producing the corresponding carboxylic acids by using only air as a reactant source under mild reaction conditions, while the isolation of the products is also directly integrated into the oxidation process. Extensibility to other reaction types is not explored yet, but we are sure that this novel synthesis conception carries a lot of possibilities.

Contact electro catalysis driven degradation of malachite green dye by RGO/ZnO nanohybrid

This work demonstrates the potential of reduced graphene/zinc oxide (RGO/ZnO) nanohybrid for the degradation of malachite green dye (MG) via involving the mechanochemistry contact electro catalysis (CEC) approach through electronic transfer. Dielectric and piezoelectric RGO/ZnO nanohybrid in contact with aqueous medium offers electron transfer via direct catalytic reaction at solid-liquid interface which promotes CEC process than that of conventional photocatalysis. RGO/ZnO nanohybrid is prepared via ultrafast microwave irradiation method in 60 s using Mangifera indica leaves extract as a green reducing agent. The prepared RGO/ZnO nanohybrid is characterized by X-ray diffraction (XRD), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR) and UV–Visible (UV–Vis) spectroscopy. XRD analysis reveals the formation of pure ZnO with wurtzite hexagonal phase and signature reflection of the RGO. Raman, FTIR and UV–Vis spectroscopy results confirm the presence of bands corresponding to ZnO and RGO and hence the formation of RGO/ZnO nanohybrid without any impurity phase. Field emission-scanning electron microscopy (FE-SEM) reveals the growth of spherical shaped ZnO nanoparticles over the RGO matrix. The average particle size of ZnO nanoparticles is ⁓ 9.2 nm. Catalytic properties of RGO/ZnO nanohybrid is investigated by using 10 mg and 20 mg dosage in aqueous solution of MG. About 85.72 % degradation efficiency for MG in 60 min is achieved by using 20 mg RGO/ZnO nanohybrid via sonication through CEC process. Probably, contact electrolysis at ZnO-water interface induces electronic exchange and generation of free radicals to degrade the dye molecules. Reaction kinetics analysis reveals the suitability of the pseudo first-order kinetics for dye degradation and reusability of RGO/ZnO nanohybrid confirms its excellent stability up to three cycles with 60 % degradation ability. This research establishes RGO/ZnO nanohybrid as highly promising catalytic agents for wastewater treatment and hazard free CEC approach.

Recent advances in Joule‐heating synthesis of functional nanomaterials for photo and electrocatalysis

AbstractBackgroundCatalyst synthesis plays a crucial role in advancing photo and electrocatalysis technologies for sustainable development. However, the traditional thermal radiation heating method suffers from the disadvantages of high energy consumption, low heat transfer efficiency, slow heating speed and long heating time, which leads to the inefficiency and cost increases in catalyst preparation.AimsThe Joule‐heating ultrafast synthesis method with rapid heating/quenching and shorter heating time has attracted much attention. Despite its potential, there is a lack of comprehensive reviews specifically addressing the synthesis of advanced photo and electrocatalysts via Joule‐heating. Therefore, this review aims to help people quickly understand the advantages of Joule‐heating in the synthesis of photo and electrocatalysts.DiscussionHerein, we firstly introduce the principles and devices of Joule‐heating, and then we discuss breakthroughs in defect modulation, heterojunction construction, single‐atom catalysts, bimetallic alloy catalysts, high‐entropy alloy catalysts and metastable catalysts achieved through Joule‐heating technology. The diverse applications of these catalysts include hydrogen evolution, oxygen evolution, oxygen reduction reactions, carbon dioxide reduction reactions, nitrogen reduction reaction and degradation of organic pollutants. Furthermore, this review provides a forward‐looking perspective on future directions for employing Joule‐heating methods in the field of photo and electrocatalysis research.ConclusionThis review highlights the pivotal role played by Joule‐heating techniques in advancing nanomaterial synthesis as well as developing sustainable high‐performance catalyst systems.

Electric Field Effects in Flash Joule Heating Synthesis.

Flash Joule heating has emerged as an ultrafast, scalable, and versatile synthesis method for nanomaterials, such as graphene. Here, we experimentally and theoretically deconvolute the contributions of thermal and electrical processes to the synthesis of graphene by flash Joule heating. While traditional methods of graphene synthesis involve purely chemical or thermal driving forces, our results show that the presence of charge and the resulting electric field in a graphene precursor catalyze the formation of graphene. Furthermore, modulation of the current or the pulse width affords the ability to control the three-step phase transition of the material from amorphous carbon to turbostratic graphene and finally to ordered (AB and ABC-stacked) graphene and graphite. Finally, density functional theory simulations reveal that the presence of a charge- and current-induced electric field inside the graphene precursor facilitates phase transition by lowering the activation energy of the reaction. These results demonstrate that the passage of electrical current through a solid sample can directly drive nanocrystal nucleation in flash Joule heating, an insight that may inform future Joule heating or other electrical synthesis strategies.

High-Entropy Metal Oxide-Coated Carbon Cloth as Catalysts for Long-Life Li-S Batteries.

Lithium-sulfur (Li-S) batteries with high specific energy density, low cost, and environmental friendliness of sulfur have been regarded as a competitive alternative to replace lithium-ion batteries. However, the shuttle effect and the sluggish conversion rate of lithium polysulfides (LiPSs) have seriously limited the practical application of Li-S batteries. Herein, high-entropy oxides grown on the carbon cloth (CC/HEO) are synthesized by a simple and ultrafast solution combustion method for the sulfur cathode. The as-prepared composites possess abundant HEO active sites for strong interaction with LiPSs, which can significantly promote redox kinetics. Besides, the carbon fiber substrate not only ensures high electrical conductivity but also accommodates large volume change, leading to a stable sulfur electrochemistry. Benefiting from the rational design, the Li-S batteries with CC/HEO as cathode skeleton exhibits good cyclability with a capacity decay rate of 0.057% per cycle after 1000 cycles at 2 C. More importantly, the Li-S batteries with 4.3 mg cm-2 high sulfur loading can still retain a high capacity retention of 78.2% after 100 cycles.

An Improved Method to Compute the Mutual Capacitance between Interdigital Transducers in Radio Frequency Surface Acoustic Wave Filters

This paper proposes an improved method to calculate the mutual capacitance between interdigital transducer (IDT) electrodes to enhance the accuracy of the traditional coupling-of-modes (COM) model, which is commonly used to simulate surface acoustic wave (SAW) filters and duplexers. In this method, the boundary element method (BEM) is adopted to obtain the capacitance per unit length in a layered medium, while the partial capacitance (PC) method is used to derive the effective relative permittivity of the multi-layered IDT. Numerical results from commercially available software are provided for comparison with the results calculated using the proposed method. The consistent results verify the validity and accuracy of this method, which also demonstrates significantly faster calculation speed compared to commercially available software. Precise electrical response prediction of a dual-mode SAW (DMS) filter can be achieved by applying this method to the COM model, and this ultra-fast calculation method can also be included in filter design optimization.

Dynamic Mode Decomposition for Transient Cavitation Bubbles Imaging in Pulsed High-Intensity Focused Ultrasound Therapy.

Pulsed high-intensity focused ultrasound (pHIFU) can induce sparse de novo inertial cavitation without the introduction of exogenous contrast agents, promoting mild mechanical disruption in targeted tissue. Because the bubbles are small and rapidly dissolve after each HIFU pulse, mapping transient bubbles and obtaining real-time quantitative metrics correlated with tissue damage are challenging. Prior work introduced Bubble Doppler, an ultrafast power Doppler imaging method as a sensitive means to map cavitation bubbles. The main limitation of that method was its reliance on conventional wall filters used in Doppler imaging and its optimization for imaging blood flow rather than transient scatterers. This study explores Bubble Doppler enhancement using dynamic mode decomposition (DMD) of a matrix created from a Doppler ensemble for mapping and extracting the characteristics of transient cavitation bubbles. DMD was first tested in silico with a numerical dataset mimicking the spatiotemporal characteristics of backscattered signal from tissue and bubbles. The performance of DMD filter was compared to other widely used Doppler wall filter-singular value decomposition (SVD) and infinite impulse response (IIR) high-pass filter. DMD was then applied to an ex vivo tissue dataset where each HIFU pulse was immediately followed by a plane wave Doppler ensemble. In silico DMD outperformed SVD and IIR high-pass filter and ex vivo provided physically interpretable images of the modes associated with bubbles and their corresponding temporal decay rates. These DMD modes can be trackable over the duration of pHIFU treatment using k-means clustering method, resulting in quantitative indicators of treatment progression.

Ultra-fast calculation method of incident angle based on underwater acoustic round-trip positioning

In underwater acoustic round-trip positioning, the incident angle calculation in constant gradient acoustic ray tracing significantly hinders the efficiency of positioning calculation. To address this issue, we proposed an ultra-fast calculation method for determining incident angle based on underwater acoustic round-trip positioning. Specifically, the method employs the k-mean++ clustering algorithm to streamline the sound velocity profile. Additionally, a function formula for the incident angle is constructed, and its partial derivative with respect to Snell's constant is derived. Finally, Newton's method is applied to iteratively calculate the incident angles of the signal emission and reception, respectively. The simulation test results demonstrate that the proposed method reduces the positioning calculation time by 80.123%, 80.105%, 80.136%, and 80.104% on four transponders compared to the traditional method. In the field experiment, the proposed method is superior to the traditional method by 81.693% in positioning calculation time. These findings indicate the significant superiority of the proposed method in positioning calculation efficiency compared to the traditional method.

Image fast reconstruction for sparse view computed tomography with reduced sampling integration time

Industrial computed tomography (CT) can detect the internal structure of objects nondestructively. Its scanning and image reconstruction are time-consuming, which limits its application in the fast detection field. In this work, we reduce the sampling integration time in sparse view CT to achieve ultra-fast scanning in only 5 s. However, this ultra-fast scanning method produces more noise and streak artifacts in the reconstructed CT images. The existing reconstruction methods cannot effectively reconstruct high quality CT images under this ultra-fast scanning. To solve this issue, a faster and higher quality CT image reconstruction method is proposed in this paper. We construct a novel objective function using multi-directional TV and adaptive non-local means (ANLM), and design a solution algorithm to solve the objective function. The multi-directional TV-norm takes into account the differences in horizontal, vertical, and 45° directional gradients to obtain more image detail information, while the ANLM-norm focuses on noise suppression. Simulation and practical experiments show that the proposed method can reconstruct higher quality CT images under faster CT scanning strategy, and the peak signal to noise ratio (PSNR) is 1.3 dB higher than the optimal baseline algorithm. On the other hand, our method converges faster and achieves a shorter CT image reconstruction time, which is 47 s shorter than the current popular iterative reconstruction methods. This reconstruction method provides a reliable scheme for faster CT scanning and image reconstruction.

Ruthenium-Based Binary Alloy with Oxide Nanosheath for Highly Efficient and Stable Oxygen Evolution Reaction in Acidic Media.

Traditional noble metal oxide, such as RuO2, is considered a benchmark catalyst for acidic oxygen evolution reaction (OER). However, its practical application is limited due to sluggish activity and severe electrochemical corrosion. In this study, Ru-Fe nanoparticles loading on carbon felt (RuFe@CF) is synthesized via an ultrafast Joule heating method as an active and durable OER catalyst in acidic conditions. Remarkably low overpotentials of 188 and 269mV are achieved at 10 and 100mA cm-2, respectively, with a robust stability up to 620 h at 10mA cm-2. When used as an anode in a proton exchange membrane water electrolyzer, the catalyst shows more than 250 h of stability at a water-splitting current of 200mA cm-2. Experimental characterizations reveal the presence of a Ru-based oxide nanosheath on the surface of the catalyst during OER tests, suggesting a surface reconstruction process that enhances the intrinsic activity and inhibits continuous metal dissolution. Moreover, density functional theory calculations demonstrate that the introduction of Fe into the RuFe@CF catalyst reduces the energy barrier and boosts its activities. This work offers an effective and universal strategy for the development of highly efficient and stable catalysts for acidic water splitting.

Large-volume focus control at 10 MHz refresh rate via fast line-scanning amplitude-encoded scattering-assisted holography

The capability of focus control has been central to optical technologies that require both high temporal and spatial resolutions. However, existing varifocal lens schemes are commonly limited to the response time on the microsecond timescale and share the fundamental trade-off between the response time and the tuning power. Here, we propose an ultrafast holographic focusing method enabled by translating the speed of a fast 1D beam scanner into the speed of the complex wavefront modulation of a relatively slow 2D spatial light modulator. Using a pair of a digital micromirror device and a resonant scanner, we demonstrate an unprecedented refresh rate of focus control of 31 MHz, which is more than 1,000 times faster than the switching rate of a digital micromirror device. We also show that multiple micrometer-sized focal spots can be independently addressed in a range of over 1 MHz within a large volume of 5 mm × 5 mm × 5.5 mm, validating the superior spatiotemporal characteristics of the proposed technique – high temporal and spatial precision, high tuning power, and random accessibility in a three-dimensional space. The demonstrated scheme offers a new route towards three-dimensional light manipulation in the 100 MHz regime.

An Ultrafast Estimation Method for Coupling Coefficient and Receiver Resonant Frequency in Universal Wireless Power Transfer Systems

An Ultrafast Estimation Method for Coupling Coefficient and Receiver Resonant Frequency in Universal Wireless Power Transfer Systems