bluuebunny/crossref_metadata_2025 huggingface dataset:
Single crystal diffraction study of Ba[H4C4O10][H3C4O10][H2CO3][HCO3], a hydrous mixed sp2/sp3-carbonate
Authors: Spahr Dominik , Bykova Elena , Bayarjargal Lkhamsuren , Milman Victor , Liermann Hanns-Peter , Winkler Björn
Published: December 2024

Ba[H4C4O10][H3C4O10][H2CO3][HCO3] is the first mixed sp2/sp3-carbonate containing both carbon trigonally coordinated in [CO3]2−-groups and tetrahedrally coordinated in [CO4]4−-groups.
Liquid-phase synthesis of Li4GeS4 and Li10GeP2S12 electrolytes using water as the main solvent
Authors: Tanigaki Hayata , Kimura Takuya , Kurioka Eiji , Motohashi Kota , Sakuda Atsushi , Tatsumisago Masahiro , Hayashi Akitoshi
Published: December 2024

Liquid-phase synthesis using water as a solvent with low environmental impact was demonstrated to synthesize sulfide electrolytes.
Cationic groups in polystyrene/O-PBI blends influence performance and hydrogen crossover in AEMWE
Authors: Hager Linus , Schrodt Maximilian , Hegelheimer Manuel , Stonawski Julian , Leuaa Pradipkumar , Chatzichristodoulou Christodoulos , Hutzler Andreas , Böhm Thomas , Thiele Simon , Kerres Jochen
Published: December 2024

The study of cationic groups in novel anion exchange membranes suggests an approach to reducing H2 crossover and improving performance.
In operando Raman microscopy of the Cu/Li1.5Al0.5Ge1.5(PO4)3 solid electrolyte interphase
Authors: Weich Ineke , Dopilka Andrew , Kasnatscheew Johannes , Winter Martin , Kostecki Robert
Published: December 2024

In operando Raman microscopy has revealed that the reduction of Li1.5Al0.5Ge1.5(PO4)3 (LAGP) to Ge particles surrounded by Li-phosphates occurs in reaction hotspots at the Cu/LAGP interface.
“Turn-on” NIR-II fluorescence of a dually quenched probe for sensitive imaging of cathepsin B in vivo
Authors: Deng Yu , Yan Kui , Xu Lingling , Liu Xiaoyang , Zhao Furong , Wang Shangfeng , Zhang Fan , Liang Gaolin , Wang Rui
Published: December 2024

Nanoparticle AF3-NP with dually quenched NIR-II fluorescence was rationally designed. Upon uptake by cancer cell, AF3-NP was cleaved by cathepsin B to yield AF3-cleaved to turn the NIR-II fluorescence “On” for sensitive tumor imaging.
A holistic approach to understanding structural, magneto-electronic, thermoelectric, and thermodynamic properties of RhMnZ (Z = Si, Ge) half Heusler alloys
Authors: Gurunani Bharti , Gupta Dinesh C.
Published: December 2024

This study analyzes RhMnZ half-Heusler alloys structural, mechanical, thermal, electronic, and thermoelectric properties. DFT and Boltzmann transport equations show metallic behavior, stability, and potential for thermoelectric applications.
Pickering multiphase materials using plant-based colloidal lignin nanoparticles
Authors: Gan Jian , Zhan Yifei , Fan Jing , Wang Jifu , Gao Qi , Huang Caoxing , Yu Wenji , Zhang Kai
Published: December 2024

A Pickering emulsion, stabilized by amphiphilic solid particles, is a highly functional and stable system that has attracted significant research interest.
Quantitative sizing of microplastics up to 20 µm using ICP-TOFMS
Authors: Sandro Fazzolari , Bodo Hattendorf , Detlef Günther
Published: December 2024

A vertically aligned sample introduction system combined with ICP-TOFMS allows the analysis of 20 µm microplastic particles.
A new calcite reference material for in situ oxygen isotope analysis using secondary ion mass spectrometry: development and application constraints
Authors: Yin Xuna , He Miaohong , Zhang Le , Deng Wenfeng , Guo Yangrui , Cui Zexian , Yang Qing , Zhang Yanqiang , Wei Gangjian
Published: December 2024

A calcite WS-1 was recommended as a reference material for oxygen isotope microanalysis by SIMS.
OoTrap: enhancing oocyte collection and maturation with a field-deployable fluidic device
Authors: Franko Roksan , de Almeida Monteiro Melo Ferraz Marcia
Published: December 2024

OoTrap is a fluidic device that captures and matures oocytes in a compact unit, reintroducing mechanical forces that enhance maturation rates, reduce chromosomal abnormalities, and support both laboratory and field applications.
Sheath-enhanced concentration and on-chip detection of bacteria from an extremely low-concentration level
Authors: Chen Xinye , Peng Ruonan , Wang Ruo-Qian , Du Ke
Published: December 2024

We develop a sheath-assisted and pneumatic-induced nano-sieve device for improved on-chip concentration and sensitive detection of Staphylococcus aureus, with a low concentration of ∼100 CFU mL−1, under a fluorescence microscope in less than 30 min.
A phosphite derivative with stronger HF elimination ability as an additive for Li-rich based lithium-ion batteries at elevated temperatures
Authors: Zheng Xiangzhen , Huang Tao , Pan Ying , Chen Yongwei , Wei Mingdeng , Wu Maoxiang
Published: December 2024

TMSPi, TMSPE, and TEP are comparatively evaluated as additives for high temperature application of a Li-rich lithium battery under high voltage and TMSPE shows the best electrochemical performance of the three phosphite-based additives.
Steering CO resistance and catalytic activity of PtRu alloy in methanol oxidation with atomically dispersed Ni
Authors: Zhang Guoqing , Li Jiankun , Li Shiyi , Wang Yixing , Lei Linfeng , Zhu Minghui , Zhuang Linzhou , Xu Zhi
Published: December 2024

The PtRu alloy with atomically dispersed Ni could adjust the electronic configuration of Pt and facilitate bond breaking between hydrogen and carbon, leading to excellent CO resistance and robust MOR activity.
Development and characterization of a gallic acid-infused topical emulgel for enhanced wound management: formulation and in vitro optimization
Authors: Dhandhi Sourav , Yeshna  , Vishal  , Monika  , Chauhan Samrat , Singh Monika , Singh Rahul Pratap , Jhawat Vikas
Published: December 2024

Development of topical emulgel containing gallic acid for wound healing.
Rapid synthesis and hydrothermal stability enhancement of Cu-SSZ-13 zeolites for nitrogen oxide removal
Authors: Su Jie , Ma Zhe , Wei Yingzhen , Zhou Yida , Shen Mao , Ren Shi-Bin , Han De-Man , Chen Mengyang , Yan Wenfu
Published: December 2024

The SSZ-13 zeolite can be synthesized in a short crystallization time of just 6 h using SAPO-18 seeds and minimal TMAdaOH, and metal precursors can significantly influence the NH3-SCR performance of bimetallic SSZ-13 zeolites.
Cobalt-catalyzed regio- and diastereoselective carbocyclization/arylation of 1,5-bisallenes
Authors: Wang Tao , Huang Hua , Guan Ji-Xun , An Xiao-Die , Tan Yun-Xuan , Tian Ping
Published: December 2024

The first non-precious cobalt-catalyzed carbocyclization/arylation of 1,5-bisallenes has been developed, affording cis-disubstituted pyrroles with high regio- and diastereoselectivity.
Dynamic pyridinethiol ligand shuttling within iron-anchored covalent organic frameworks boosts CO2 photoreduction
Authors: Zhang Yong-Kang , Zhao Lan , Terent'ev Alexander O. , He Liang-Nian
Published: December 2024

A dynamic D⋯M–A structure COF can effectively suppress photogenerated charge recombination, achieving rapid electron transfer via round-trip shuttling of pyridinethiol ligands within iron-anchored COFs and thereby enhancing PCO2RR performance.
A fabric-based multi-functional solar evaporator with all-weather efficient continuous evaporating capability through photothermal and electrothermal effects
Authors: Chen Chuanliang , Cheng Minhan , Qu Yuliang , Tian Ke , Li Qianyang , Fu Qiang , Deng Hua
Published: December 2024

Solar-driven desalination is a promising strategy to alleviate the water crisis.
An adsorption-catalysis bifunctional MoS2/Mo@rGO host material for lithium–sulfur power batteries
Authors: Cheng Chang , Wang Tianle , Guan Zefeng , Tao Tao , Liu Jianpeng , Zhu Jiliang
Published: December 2024

A MoS2–Mo@rGO composite host material enhances lithium polysulfide adsorption and reaction kinetics in lithium–sulfur batteries, achieving a 4 minute drone activation.
Direct covalent attachment of fluorescent molecules on plasma polymerized nanoparticles: a simplified approach for biomedical applications
Authors: Haidar Laura Libnan , Wang Yuheng , Gilmour Aaron D. , Austria Elmer , Boumelhem Badwi B. , Aziz Khan Naveed , Fadzil Arifah Anwar , Fraser Stuart T. , Bilek Marcela M. M. , Akhavan Behnam
Published: December 2024

This paper provides first-time evidence of covalent attachment of fluorescent molecules to plasma polymerised nanoparticles for diagnostic and therapeutic applications.
Frontiers in fluorescence imaging: tools for the in situ sensing of disease biomarkers
Authors: Yang Lei , Hou Hongwei , Li Jinghong
Published: December 2024

A comprehensive overview of recent advancements in fluorescence imaging techniques for in situ sensing of various biomarkers, emphasizing the transformative potential of artificial intelligence in shaping the future of bioimaging.
Nitrogen doped carbon quantum dots: a multifaceted carbon nanomaterial that interferes in an amyloid-forming trajectory
Authors: ElMorsy Sherin M. , Gutierrez Denisse A. , Valdez Salvador , Kumar Jyotish , Aguilera Renato J. , Noufal Mohamed , Chinnam Sampath , Sarma Hemen , Narayan Mahesh
Published: December 2024

LAdN-CQDs have been used to inhibit fibril formation, display biocompatibility, reduce reactive oxygen species, and safeguard against apoptosis, indicating promise in neuroprotection.
Polymorphism in mechanochromic luminogens: recent advances and perspectives
Authors: Gavale Ramakant , Khan Faizal , Misra Rajneesh
Published: December 2024

Polymorphism in mechanochromic materials is a subject of growing research interest due to its implication in various optoelectronic devices.
Recorded Word Recognition Testing Is Worth the Time
Authors: Austin Allie , Ladner Kathryn , Mendel Lisa Lucks
Published: December 2024

Purpose:

The goal of this study was to provide evidence of the inherent variability associated with monitored live voice (MLV) presentation methods and encourage audiologists to more closely follow best practice of using recorded stimuli. To accomplish the goal, administration times for word recognition testing were compared between MLV and MP3 recorded stimuli presented directly from an audiometer (computer assisted, CA). Furthermore, the variability of administration time across testers was evaluated.

Method:

Fifty-word NU-6 lists were presented via MLV and CA to listeners with typical hearing (TH; defined as a four-frequency [500, 1000, 2000, and 4000 Hz] pure-tone average [PTA] of 20 dB HL or better) and hearing loss (HL; defined as a four-frequency PTA poorer than 20 dB HL). Audiologists and doctor of audiology students administered the word lists. Administration times were compared between the two presentation methods (MLV and CA).

Results:

MLV administration time was significantly shorter than CA presentation time for both the TH and HL groups. There was also a significant difference in word recognition scores (WRS) between the TH and HL groups only when using the CA method. Most notably, there was significantly more variability in the administration time for MLV presentation across testers compared to the CA method. Data were compared to Mendel and Owen (2011), and MLV administration time was found to be significantly shorter than CA and compact disk (CD) administration time.

Conclusions:

Despite the shorter average administration time for MLV presentation compared to CA or CD, the significant variability in administration time among individual testers limits the clinical value of the test results. In addition, WRS for those with hearing loss were significantly poorer than those with TH when using CA but not for MLV, indicating that MLV is not sensitive to the presence of sensorineural hearing loss. Thus, using recorded word recognition is strongly recommended.
Analysis of the influence of configuration parameters on the electric field distribution of the main insulation structure of valve‐side winding of converter transformer considering electro‐thermal coupling
Authors: Yang Lijun , Cheng Zhidong , Cheng Li , Liao Ruijin
Published: December 2024

The variation of configuration parameters in the insulation structure of transformers significantly impacts the distribution of electric fields. Current research on electric field distribution calculations often overlooks the influence of electric field intensity and temperature on this distribution. However, considering that the direct current conductivity of oil‐paper materials is easily affected by both electric field intensity and temperature, any changes in their conductivity will inevitably affect the electric field distribution. Therefore, this paper incorporates the influence of electric field intensity and temperature on the calculation process of the electric field distribution in the main insulation structure of the valve‐side winding. Additionally, it calculates the distribution of multi‐fields for a wide range of structural configuration parameters. Consequently, the influence law of insulation structure configuration parameters on the electric field distribution of the main insulation structure of valve‐side winding for converter transformer when considering electro‐thermal coupling is obtained. This finding can serve as a crucial reference for designing and optimising converter transformers.
Chance‐constrained scheduling considering frequency support from electric vehicles under multiple uncertainties
Authors: Liu Yifeng , Zeng Wenyuan , Chen Meng , He Zhongshi , Yuan Yi , Ding Tao
Published: December 2024

With the share of renewable generation increasing, considerable synchronous generators have been displaced. This trend results in the decline of system inertia and thus raises the frequency secure issue. Concurrently, electric vehicles (EVs) proliferate. Numerous EVs hold a huge potential of frequency regulation in case of contingency as EVs are able to achieve primary frequency responses (PFRs) via vehicle to grid chargers. However, the value of frequency responses from aggregated EVs has not fully exploited. This paper, proposes a chance constrained scheduling model incorporating the ability of PFRs from aggregated EVs. The proposed model characterizes uncertainties associated PFR capacities from aggregated EVs and wind power forecast errors by the Wasserstein‐metric ambiguity sets, which do not rely on distributional assumption, and then formulates uncertainties‐related constraints as distributionally robust (DR) chance constraints. These DR chance constraints are reformulated as tractable linear programs. Consequently, the proposed model leads to a mixed‐integer linear program. Numerical results on a modified IEEE 39‐bus system show that incorporating PFR from EVs can reduce total costs from $4,540,396 to $4,431,233, which is reduced by 2.4%. The proposed model also achieves better reliability compared to traditional methods, demonstrating the distributionally robust optimization in enhancing electricity scheduling and rising renewable integration.
Numerical investigation of instabilities in over-pressured magnetized relativistic jets
Authors: Hu Xu-Fan , Mizuno Yosuke , Fromm Christian M.
Published: December 2024

Context. Relativistic jets from active galactic nuclei are observed to be collimated on the parsec scale. When the pressure between the jet and the ambient medium is mismatched, recollimation shocks and rarefaction shocks are formed. Previous numerical simulations have shown that instabilities can destroy the recollimation structure of jets.

Aims. In this study, we aim to study the instabilities of nonequilibrium over-pressured relativistic jets with helical magnetic fields. Especially, we investigate how the magnetic pitch affects the development of instabilities.

Methods. We performed 3D relativistic magnetohydrodynamic simulations for different magnetic pitches, as well as a 2D simulation and a relativistic hydrodynamic simulation which served as comparison groups.

Results. In our simulations, Rayleigh-Taylor instability (RTI) is triggered at the interface between the jet and ambient medium in the recollimation structure of the jet. We find that when the magnetic pitch decreases, the growth of RTI becomes weak but, interestingly, another instability – the current-driven (CD) kink instability – is excited. The excitement of CD kink instability after passing the recollimation shocks can match the explanation of the quasi-periodic oscillations observed in BL Lac qualitatively.
Relationship between Intrapartum Continuous Glucose Monitoring Values and Neonatal Hypoglycemia in Individuals with Diabetes
Authors: Fishel Bartal Michal , Nazeer Sarah A. , Ashby Cornthwaite Joycelyn , Bitar Ghamar , Blackwell Sean C. , Pedroza Claudia , Chauhan Suneet P. , Saad Antonio , Saade George , Sibai Baha M.
Published: December 2024

Objective We aimed to evaluate the relationship between intrapartum continuous glucose monitoring (CGM) and neonatal hypoglycemia (NH) in individuals with diabetes.

Study Design a multicenter prospective study (November 2021–December 2022) of laboring individuals with pregestational or gestational diabetes at ≥34 weeks. Cohorts had a blinded CGM placed from admission through delivery and were monitored with fingerstick (FS) according to usual care. The primary outcome was NH. Secondary neonatal outcomes included neonatal intensive care unit (NICU) length of stay, need for intravenous (IV) glucose therapy, hyperbilirubinemia, respiratory distress, or respiratory distress syndrome. Time in the target range (TIR; range 70–110 mg/dL) and time above the target range (TAR; >110 mg/dL) were expressed as a percentage of all CGM readings, and mean glucose was obtained. Youden index was used to choose the cut point for TAR and prediction of NH.

Results Of 9,479 deliveries during the study period, 202 (2.1%) met the inclusion criteria, and 112 (56%) participants were enrolled (n = 7 did not have available CGM data). Of the study participants, 45 (40%) had pregestational diabetes, and 67 (60%) had gestational diabetes. The mean glucose in labor using a CGM was 102.6 mg/dL (interquartile range [IQR]:89.9, 113.5 mg/dL), and the average percentage of TIR was 62.1% (IQR, 36.9, 85.6). CGM and FS were poor predictors of NH, with no differences in area under the curve (AUC) of mean glucose as a predictor (0.64, 95% CI: 0.48–0.23 vs. 0.53, 95% CI: 0.4–0.6, respectively). The best cut-off for the prediction of NH was a TAR of 61%, with 23% (n = 24) being above the threshold. The rate of NH for TAR >61% versus ≤61% was 45.8 versus 25.9% (p = 0.06). Neonates born to individuals with TAR >61% were more likely to require continuous positive airway pressure after delivery and had a higher cord c-peptide level.

Conclusion In this prospective study of laboring individuals with diabetes, intrapartum CGM TAR was associated with a higher rate of NH.

Key Points
First-principles prediction of zone-center optical phonon linewidths and IR spectra of hexagonal boron nitride
Authors: Guo Ziqi , Sokalski Peter , Han Zherui , Cheng Yanhua , Shi Li , Taniguchi Takashi , Watanabe Kenji , Ruan Xiulin
Published: December 2024

Raman and infrared (IR) spectra provide rich information about materials. In this study, we employ first-principles calculations to predict the temperature-dependent linewidths of zone-center phonon modes, along with the IR dielectric function in bulk hexagonal boron nitride. We include the contributions of three-phonon, four-phonon scattering, and phonon renormalization, and our predictions show good agreement with our own experimental results as well as those in the literature. Our findings show that the temperature dependency of phonon linewidth would be strengthened by considering four-phonon scattering while weakened by further including phonon renormalization. After considering all these effects, four-phonon scattering shows a significant or even leading contribution to the linewidth over three-phonon scattering, especially at elevated temperatures.
Room temperature polarization-resolved Raman and photoluminescence in uniaxially strained layered MoS2
Authors: Ali Shahzad Akhtar , Ahmed Bilal , Javed Ahsan , Muzaffar M. Usman , Bano Afsar , Ulhaq Ata
Published: December 2024

Transition metal dichalcogenides (TMDCs) are one of the material systems of choice toward achieving room temperature quantum coherence. Externally applied strain is used as a more common control mechanism to tune electro-optical properties in TMDCs like molybdenum disulfide (MoS2). However, room temperature electron–phonon interactions in the presence of strain in transition metal dichalcogenides are still not fully explored. In this work, we employ uniaxial strain dependent Raman and photoluminescence (PL) studies on monolayer and bilayer MoS2 to explore electron–phonon physics. Helicity-resolved Raman in MoS2 obeys robust selection rules. Our studies reveal clear modification in these helicity-based selection rules in the presence of moderate uniaxial strain (ϵ = 0.4%–1.2%). The selection rules are restored upon clear symmetry breaking of the in-plane vibrational mode (ϵ > 1.2%). We assign these changes to the onset of Fröhlich interaction in this moderate strain regime. The changes in Raman scattering are accompanied by changes in valley selective relaxation observed through non-resonant photoluminescence (PL). The moderate strain regime also exhibits the onset of PL polarization for indirect excitonic emission under non-resonant excitation. Our experimental observations point toward electron–phonon coupling mechanisms affecting both valley-selective electron relaxation during PL emission as well as polarization-selective Raman scattering of two-dimensional semiconductors at room temperature.
A low-temperature synthesis of strongly thermochromic W and Sr co-doped VO2 films with a low transition temperature
Authors: Kaufman Michal , Vlček Jaroslav , Houška Jiří , Farrukh Sadoon , Haviar Stanislav , Čerstvý Radomír , Kozák Tomáš
Published: December 2024

The reversible semiconductor-to-metal transition of vanadium dioxide (VO2) makes VO2-based coatings a promising candidate for thermochromic smart windows, reducing the energy consumption of buildings. We report low-temperature (320 °C) depositions of thermochromic V1−x−yWxSryO2 films with a thickness of 71–73 nm onto 170–175 nm thick Y-stabilized ZrO2 layers on a 1 mm thick conventional soda-lime glass. The developed deposition technique is based on reactive high-power impulse magnetron sputtering with a pulsed O2 flow feedback control allowing us to prepare crystalline W and Sr co-doped VO2 films of the required stoichiometry without any substrate bias or post-deposition annealing. The W doping of VO2 decreases the transition temperature below 25 °C, while the Sr doping of VO2 increases the integral luminous transmittance, Tlum, significantly due to widening of the visible-range optical bandgap, which is consistent with lowering of the absorption coefficient of films. We present the discussion of the effect of the Sr content in the metal sublattice of VO2 on the electronic and crystal structure of V1−x−yWxSryO2 films, and on their temperature-dependent optical and electrical properties. An optimized V0.855W0.018Sr0.127O2 film exhibits a high Tlum = 56.8% and modulation of the solar energy transmittance ΔTsol = 8.3%, which are 1.50 times and 1.28 times, respectively, higher compared with those of the V0.984W0.016O2 film. The achieved results constitute an important step toward a low-temperature synthesis of large-area thermochromic VO2-based coatings for future smart-window applications, as it is easy to further increase the Tlum and ΔTsol by >6% and >3%, respectively, using a 280 nm thick top SiO2 antireflection layer.
Switching, amplifying, and chirping diode lasers with current pulses for high bandwidth quantum technologies
Authors: Buser Gianni
Published: December 2024

A series of simple and low-cost devices for switching, amplifying, and chirping diode lasers based on current modulation are presented. Direct modulation of diode laser currents is rarely sufficient to establish precise amplitude and phase control over light, as its effects on these parameters are not independent. These devices overcome this limitation by exploiting amplifier saturation and dramatically outperform commonly used external modulators in key figures of merit for quantum technological applications. Semiconductor optical amplifiers operated on either rubidium D line are recast as intensity switches and shown to achieve ON:OFF ratios >106 in as little as 50 ns. Current is switched to a 795 nm wavelength (Rb D1) tapered amplifier to produce optical pulses of few nanosecond duration and peak powers of 3 W at a similar extinction ratio. Fast rf pulses are applied directly to a laser diode to shift its emission frequency by up to 300 MHz in either direction and at a maximum chirp rate of 150 MHz ns−1. Finally, the latter components are combined, yielding a system that produces watt-level optical pulses with arbitrary frequency chirps in the given range and <2% residual intensity variation, all within 65 ns upon asynchronous demand. Such systems have broad application in atomic, molecular, and optical physics and are of particular interest to fast experiments simultaneously requiring high power and low noise, for example, quantum memory experiments with atomic vapors.
Record-high power, low phase noise synchronously-pumped optical parametric oscillator tunable from 2.7 to 4.7 μm
Authors: Pecile Vito F. , Leskowschek Michael , Modsching Norbert , Wittwer Valentin J. , Südmeyer Thomas , Heckl Oliver H.
Published: December 2024

Within the domain of optical frequency comb systems operating in the mid-infrared region, extensive exploration has been undertaken regarding critical parameters, such as stabilization, coherence, or spectral tunability. Despite this, certain essential parameters remain inadequately addressed, particularly concerning light source stability at high average powers. This study explores stability limitations of an optical parametric oscillator system when scaling to several watts of average power of the idler. Notably, the highest average power reported in the 3–5 μm region, reaching 10.3 W for the idler output at 3.1 μm, is achieved. Additionally, we analyze the phase noise and beam quality of both idler and signal beams and identify the onset of higher order modes as limiting for stability at high-power operation. Finally, we estimate the free-running optical linewidth of our idler beam to be ∼300 kHz, undermining the high passive temporal stability of our source. These findings represent a significant advancement toward the realization of highly stable high-power optical frequency combs in the mid-infrared region, thereby facilitating applications previously constrained by light source average powers and quality limitations.
Gate voltage tuning of photo-responses in n-AlGaAs/GaAs/AlGaAs double-heterojunction
Authors: Kawazu Takuya
Published: December 2024

We demonstrate that the gate voltage Vg tunes the Schottky photocurrent ISG for the irradiation of two lights (Light A and B) in an n-AlGaAs/GaAs/AlGaAs double-heterojunction. Light A is a 975-nm laser that illuminates the entire Schottky gate region at 280 μW/mm2. Light B is a 670-nm laser that locally illuminates the ungated region at 0.4 μW. When Vg = 0 V, Light B doubles ISG for Light A. At Vg = 87 mV, ISG is generated only when both Light A and B are irradiated simultaneously, like the logical operation A∩B. When Vg = 165 mV, ISG is induced only for the illumination of Light A alone, like A∩B̄.
Active control of wake-induced vibration using deep reinforcement learning
Authors: Ren Feng , Ding Zihan , Zhao Yuanpu , Song Dong
Published: December 2024

Wake-induced vibration (WIV) is a typical type of flow-induced vibration. Effectively controlling such vibration is of significant value in engineering fields. In this study, we focus on the feasibility, effectiveness, and efficiency of the deep reinforcement learning (DRL)-guided active flow control for WIV control. Here an elastically mounted circular cylinder is interfered by the wake of an upstream equal-size cylinder at Reynolds number 100. With different center-to-center in-line distances, the unwanted vibration is noted to be more complicated than the vortex-induced vibration, which is then controlled by the rotary control with sensory motor cues as feedback signals. The control strategy is established by the DRL and is trained in the numerical environment built upon the lattice Boltzmann solver. For the tandem configuration, the DRL learns effective control strategies that can control the vibration amplitude by 99.7%, 99.2%, and 95.7%, for the cases with nondimensionalized gap length of 2, 6, and 8, respectively. Both time-averaged flow fields and vortex dynamics are discussed, revealing that the DRL-guided control learns different control strategies for different gap spacing. With the successfully learned strategy in tandem configuration, the WIV in staggered configuration is further explored based on the transfer learning. The vibration amplitudes of all cases in the staggered configuration are mitigated by more than 97%. To conclude, this study confirms that the DRL is effective in situations involving strong wake interference. It is anticipated that the DRL can provide a general solution for controlling flow-induced vibration.
Predicting the passive control of fluid forces over circular cylinder in a time dependent flow using neuro-computing
Authors: Asghar Atif , Mahmood Rashid , Majeed Afraz Hussain , Alotaibi Hammad , Refaie Ali Ahmed
Published: December 2024

The objective of this research is to combine Artificial Neural Networks (ANNs) and Computational Fluid Dynamics (CFD) approaches to leverage the advantages of both methods. To achieve this goal, we introduce a new artificial neural network architecture designed specifically for predicting fluid forces within the CFD framework, aiming to reduce computational costs. Initially, time-dependent simulations around a rigid cylinder and a passive device (attached and detached) were conducted, followed by a thorough analysis of the hydrodynamic drag and lift forces encountered by the cylinder and passive device with various length L=0.1,0.2,0.3 and gap spacing Gi=0.1,0.2,0.3. The inhibition of vortex shedding is noted for gap separations of 0.1 and 0.2. However, a splitter plate of insufficient length or placed at an unsuitable distance from an obstacle yields no significant benefits. The finite element method is employed as a computational technique to address complex nonlinear governing equations. The nonlinear partial differential equations are spatially discretized with the finite element method, while temporal derivatives are addressed using a backward implicit Euler scheme. Velocity and pressure plots are provided to illustrate the physical aspects of the problem. The results indicate that the introduction of a splitter plate has reduced vortex shedding, leading to a steady flow regime, as evidenced by the stable drag and lift coefficients. The data obtained from simulations were utilized to train a neural network architecture based on the feed-forward backpropagation algorithm of Levenberg–Marquardt. Following training and validation stages, predictions for drag and lift coefficients were made without the need for additional CFD simulations. These results show that the mean square error values are very close to zero, indicating a strong correlation between the fluid force coefficients obtained from CFD and those predicted by the ANN. Additionally, a significant reduction in computational time was achieved without sacrificing the accuracy of the drag and lift coefficient predictions.
Novel pseudo-hexagonal montmorillonite model and microsecond MD simulations of hydrate formation in mixed clay sediments with surface defects
Authors: Mi Fengyi , Pang Jiangtao , Li Wei , Moultos Othonas A. , Ning Fulong , Vlugt Thijs J. H.
Published: December 2024

Both CH4 hydrate accumulation and hydrate-based CO2 sequestration involve hydrate formation in mixed clay sediments. The development of realistic clay models and a nanoscale understanding of hydrate formation in mixed clay sediments are crucial for energy recovery and carbon sequestration. Here, we propose a novel molecular model of pseudo-hexagonal montmorillonite nanoparticles. The stress–strain curves of tension, compression, and shear of pseudo-hexagonal montmorillonite nanoparticles exhibit linear characteristics, with tension, compression, and shear moduli of ∼435, 410, and 137 GPa, respectively. We perform microsecond molecular dynamics simulations to study CH4 and CH4/CO2 hydrate formation in montmorillonite–illite mixed clay sediments with surface defects. The results indicate that hydrate formation in mixed clay sediments is significantly influenced by the presence of clay defects. CH4 and CH4/CO2 mixed hydrates are challenging to form at the junction between the inside and outside clay defects. CH4 and CH4/CO2 mixed hydrates exhibit a preference for forming outside the clay defects rather than inside the clay defects. Some CH4 and CO2 molecules from the inside clay defect migrate to the outside clay defect, thereby promoting CH4 and CH4/CO2 mixed hydrate formation outside the clay defects. This molecular insight advances the development of clay particle models and expands an understanding of natural gas hydrate accumulation and hydrate-based CO2 sequestration.
Real-time three-dimensional monitoring and analysis of perovskite solar cell using short wavelength infrared digital holography
Authors: Yuan Enhui , Huang Haochong , Zhang Dongshun , Zheng Zhiyuan , Sun Dexin , Dong Jingjing , Qiu Yifeng
Published: December 2024

The quality and crystallization process of all-inorganic perovskite films play a crucial role in the performance of solar cells. However, traditional detection methods lack three-dimensional depth information and real-time capabilities, hindered by strong visible light absorption, posing challenges to research. Here, a simple digital holography technique is proposed that offers real-time, nondestructive, three-dimensional phase imaging with low absorption characteristics in the short-wave infrared range. The use of short-wave infrared reduces the negative impact of visible light and vibrations in the environment on detection accuracy, while being nearly non-absorbing. The proposed method operates at a speed of 15 Hz, combining a lensless vertical structure, holographic reconstruction algorithm, and phase unwrapping algorithm to achieve real-time three-dimensional observation without image distortion and with low noise of the crystallization process of CsPbBr3 perovskite quantum dots (PQDs)/ethylene-vinyl acetate solution, which crystallizes in 39 s. Subsequently, employing minimum bounding rectangle, field stitching, intensity registration, and sub-pixel level calibration algorithms, real-time characterization is performed on the large-sized droplet of polymethyl methacrylate-matrix-encapsulated CsPbBr3 perovskite quantum dots, which has a crystallization time of 1285 s, without being limited by the field of view. Finally, using this system, the surface quality of the film is assessed, revealing fluctuations at the edge and fabrication defects of the perovskite film. Experimental results demonstrate the potential of short-wave infrared digital holography in enhancing the film formation process and quality inspection. By leveraging this technology, advancements in the development of high-performance all-inorganic perovskite solar cells can be fostered, optimizing global energy output.
Optothermal trapping of microparticles near an absorbing reflective film with an annular beam
Authors: Chen Dong , Jia Jie , Meng Chun , Yu Panpan , Li Chen-Xu , Zhong Min-Cheng
Published: December 2024

Optothermal manipulation technologies trap and manipulate microparticles under a light-controlled temperature gradient. In this paper, we demonstrate the possibilities of optothermal trap, which is generated by an annular beam irradiating on an absorbing reflective film to capture the microparticles. The particles are subjected to thermal and optical gradient forces. First, we investigate the particle trapping near a non-absorbing reflective surface to understand the action of the optical force of annular beam. The results show that the optical force cannot trap the particles near a reflective surface. Second, an annular beam is generated by Gaussian beam shaping with the aid of axicons, which is then used to irradiate and heat a gold film to create an optothermal trap. The induced thermal gradient and thermal convection can bind the particles in the center of the annular spot. The trapping stiffness of the optothermal trap is 8.1 ± 2.9 fN/μm at a laser power of 100 mW.
A hybrid quantum-classical framework for computational fluid dynamics
Authors: Ye Chuang-Chao , An Ning-Bo , Ma Teng-Yang , Dou Meng-Han , Bai Wen , Sun De-Jun , Chen Zhao-Yun , Guo Guo-Ping
Published: December 2024

Recent advancements in quantum computing provide opportunities to address the challenges of computational resource limitations in computational fluid dynamics (CFD). This work presents a hybrid quantum-classical CFD framework that leverages quantum linear algorithms to practical flow simulations. By transforming nonlinear fluid dynamics problems into linear systems, the framework employs quantum linear algorithms to compute solutions, effectively integrating quantum and classical computing approaches. Furthermore, this framework employs subspace methods to map the original large-scale linear systems to small ones solved by quantum linear algorithms, thereby enabling the solution of large-scale problems using the currently limited quantum resources. We applied the famous Harrow–Hassidim–Lloyd (HHL) algorithm and variational quantum linear solver to simulate complex flows, including unsteady flows around a cylinder, simulation of an aircraft with turbulence model, and combustion flows. The performance and quantum resource consumption of these algorithms were evaluated in practical flow scenarios, demonstrating their effectiveness with an average relative error lower than 0.001%. We conducted quantum resource and convergence analyses to adapt this framework for use with near-term quantum computers. Our framework supports simulations of up to 9.4 × 106 grid cells, marking a significant advancement from previous quantum approaches limited to simple flows. This paper not only offers a way for employing quantum linear algorithms in solving complex flow problems but also provides insights into optimizing quantum algorithms for CFD applications, pushing forward the practical utilization of quantum CFD.
Attitude motion and nonlinear free-surface deformation of stone-skipping over shallow water
Authors: Li Jipeng , Wang Fan , Cao Ming , Yao Linquan , Wu Bing , Su Xianglong , Han Jae-hung , Cao Dengqing , Tian Yishen
Published: December 2024

Stone-skipping is a common yet complex motion that involves rigid-body dynamics and fluid–structure interaction (FSI). While many computational fluid dynamics methods are used to simulate the interaction between a stone and fluid, little research has been done to consider the stone, fluid, and fluid boundary as a whole in a simulation. This study, focuses on the attitude motion and free-surface deformation of stone-skipping over shallow water to investigate how the boundary effect of FSI impacts ricochet behaviors. Initially, we establish an iteration framework for the stone-skipping FSI issue based on a weakly compressible smoothed particle hydrodynamics (SPH) method with a Riemann solver. We conduct particle-independence verification and simulate several cases under varying water heights. Additionally, we analyze and compare ricochets in deep and shallow cases with different incident angles and initial pitch angles. The numerical results demonstrate that in shallow flow scenarios, the “comma-shaped” high-pressure area is compressed by the stone and the fluid boundary, leading to a more moderate variation in pitch angle. Stone-skipping in shallow water typically covers a shorter distance and reaches a lower height compared to deep water cases. Changes in the incident angle show that shallow water hinders successful skipping. Futhermore, different initial pitch angles reveal that water height directly impact the stone's trajectory in both horizontal and vertical directions. These highlight the connection between motion patterns and parameters, offering a reliable numerical prediction for the stone-skipping problem using the Riemann SPH method.
Research and design of transient test platform for DC current transformer
Authors: Zhang Ying , Zhang Xu
Published: December 2024

This article studies the design and simulation of a transient test platform for DC current transformers to verify the effectiveness of the design scheme. DC current transformers convert large currents on the primary side into small currents on the secondary side through electromagnetic induction principles and are widely used in power systems. In order to verify the feasibility of the design scheme, simulation research was adopted, and the simulation parameters were the same as the actual scheme, including controllable current source parameters, cable parameters, and MOS switch branches. The simulation results show that the designed DC transient square wave current source can effectively compensate for the impulse current, and the output current waveform is stable, meeting the design requirements.
Flow field recovery in restricted domains using a generative adversarial network framework
Authors: Yousif Mustafa Z. , Zhou Dan , Yu Linqi , Zhang Meng , Mohammadikarachi Arash , Sub Lee Jung , Lim Hee-Chang
Published: December 2024

This study aims to reconstruct the complete flow field from spatially restricted domain data by utilizing an enhanced super-resolution generative adversarial network (ESRGAN) model. The difficulty in flow field reconstruction lies in accurately capturing and reconstructing large amounts of data under nonlinear, multi-scale, and complex flow while ensuring physical consistency and high computational efficiency. The ESRGAN model has a strong information mapping capability, capturing fluctuating features from local flow fields. The effectiveness of the model in reconstructing the whole domain flow field is validated by comparing instantaneous velocity fields, flow statistical properties, and probability density distributions. Using laminar bluff body flow from direct numerical simulation (DNS) as a priori case, the model successfully reconstructs the complete flow field from three non-overlapping limited regions, with flow statistical properties perfectly matching the original data. Validation of the power spectrum density for the reconstruction results also proves that the model could conform to the temporal behavior of the real complete flow field. Additionally, tests using DNS turbulent channel flow with a friction Reynolds number (Reτ=180) demonstrate the ability of the model to reconstruct turbulent fields, though the quality of results depends on the number of flow features in the local regions. Finally, the model is applied to reconstruct turbulence flow fields from particle image velocimetry (PIV) experimental measurements, using limited data from the near-wake region to reconstruct a larger field of view. The turbulence statistics closely match the experimental data, indicating that the model can serve as a reliable data-driven method to overcome PIV field-of-view limitations while saving computational costs.
Influence of liquid–vapor phase change on the self-propelled motion of droplets on wettability gradient surfaces
Authors: Cunha Vitor H. C. , Dorao Carlos A. , Fernandino Maria
Published: December 2024

Self-propelled motion of sessile droplets on gradient surfaces is key to the advancement of microfluidic, nanofluidic, and surface fluidic technologies. Precise control over droplet dynamics, which often involves liquid–vapor phase transitions, is crucial for a variety of applications, including thermal management, self-cleaning surfaces, biochemical assays, and microreactors. Understanding how specific phase changes like condensation and evaporation affect droplet motion is essential for enhancing droplet manipulation and improving transport efficiency. We use the thermal Navier–Stokes–Korteweg equations to investigate the effects of condensation and evaporation on the motion and internal dynamics of droplets migrating across a surface with a linear surface energy profile. The study focuses on the early dynamics of self-propelled motion of a phase changing droplet at sub-micron scale before viscous forces are comparable with the gradient forces. Our results demonstrate that phase change significantly affects the self-propelled motion of droplets by reshaping interfacial mass flux distributions and internal flow dynamics. Condensation increases droplet volume and promotes extensive spreading toward regions of higher wettability, while evaporation reduces both volume and spreading. These changes in droplet shape and size directly affect the driving forces of motion, augmenting self-propulsion through condensation and suppressing it during evaporation. Additionally, each phase change type generates distinct internal flow patterns within the droplet, with condensation and evaporation exhibiting unique circulatory movements driven by localized phase changes near the contact lines.
A novel concept of pre-chamber turbulent jet ignition-induced liquid ammonia spray flame
Authors: Zhong Lijia , Zhao Wanhui , Wei Haiqiao , Shu Gequn , Zhou Lei
Published: December 2024

Ammonia is one of the most promising alternative fuels owing to its nature of zero-carbon emission. However, the weak ignition characteristic of ammonia imposes a great hindrance on its application on engines. In the present work, a novel concept of pre-chamber turbulent jet ignition (TJI) induced liquid ammonia spray flame based on a high-pressure injection in a constant-volume chamber is proposed. The ignition modes associated with flame development of the transient ammonia spray flame are investigated. The effects of mixture reactivity in the pre-chamber and turbulent jet velocity are investigated. During the TJI-induced ammonia spray flame process, the three distinguished stages, including pre-chamber combustion, partially premixed combustion, and mixing-controlled combustion, are observed. The ignition takes place in the jet-liquid ammonia spray interaction region, but the flame fails to stabilize and propagates downstream along the ammonia spray. However, a spray flame is ignited when the hot combustion products are re-entrained by the ammonia spray, with the liftoff length gradually decreasing. The effects of mixture reactivity are further explored by enriching the pre-chamber mixture to φp = 3. The results indicate that a richer mixture can extend the ignition ability, as the critical oxygen concentration necessary for successful ignition decreases. In addition, a combustion mode transition of extinction-re-ignition phenomenon of spray flame is observed. The fundamental mechanism for the extinction-re-ignition phenomenon is attributed to the cooling effect of flash boiling and re-entrainment of hot combustion products. Furthermore, different nozzle diameters are employed to study the effects of turbulent jet velocity on the ignition tolerance. It can be concluded that a lower turbulent jet velocity can extend the ignition ability in two aspects. On the one hand, the slower hot jet increases the ignition energy by enabling a sufficient mixing between the hot jet and the ammonia spray. On the other hand, the reduced turbulence intensity weakens the turbulent heat dissipation that suppresses ignition. This work provides insightful views for ammonia compression engines.