bluuebunny/crossref_metadata_2025 huggingface dataset:
Bio-energy-powered microfluidic devices
Authors: Li Yuhan , Xu Chuangyi , Liao Yifan , Chen Xiao , Chen Jiang , Yang Fan , Gao Mingyuan
Published: December 2024

Bio-microfluidic technologies offer promising applications in diagnostics and therapy, yet they face significant technical challenges, particularly in the need for external power sources, which limits their practicality and user-friendliness. Recent advancements have explored innovative methods utilizing body fluids, motion, and heat to power these devices, addressing the power supply issue effectively. Among these, body-motion and body-heat-powered systems stand out for their potential to create self-sustaining, wearable, and implantable devices. In this Perspective, we focus on the principles and applications of hydrovoltaic cells, biofuel cells, and piezoelectric and triboelectric nanogenerators. Recent strides in energy conversion efficiency, coupled with the development of biocompatible and durable materials, are driving innovation in bio-integrated electronics. Integration with bio-microfluidic platforms further enhances the linkage to the human body and the potential of these devices for personalized healthcare applications. Ongoing research into these areas promises to deliver sustainable and user-friendly solutions for continuous monitoring, diagnostics, and therapy, potentially revolutionizing the landscape of healthcare delivery.
Investigation on the early pressure load characteristics of bubbles in near-field underwater explosion with condensed-phase CL-20 explosive detonation
Authors: Hao Yi , Sheng Zhenxin , Yan Bo , Xie Teng , Zhang Lunping , Mao Haibin , Yu Jun
Published: December 2024

This study investigates the early pressure characteristics of CL-20 explosives in near-field underwater explosions, focusing on the second ultra-high-pressure pulse in the detonation product zone. We use a compressible multiphase fluid solver with high-order finite difference schemes, including fifth-order weighted essentially non-oscillatory for spatial and third-order total variation diminishing Runge–Kutta for temporal discretization. The level-set method and modified ghost fluid method accurately capture multiphase interface dynamics. Validation against 1D detonation wave tests confirms the accuracy of our burn model. Numerical simulations of cylindrical and spherical CL-20 charges under near-field conditions show good agreement with the experimental data, highlighting the model’s precision in predicting shock wave propagation and interface motion. In spherical charges, the second pulse arises from rarefaction wave reflections within the gaseous products. The analysis of peak pressures at various distance-to-radius ratios provides insights into pressure distribution. These findings demonstrate the effectiveness of our numerical model in simulating complex detonation phenomena, offering valuable insights for both theoretical and practical applications.
Asynchronous-bit-rate differential phase-shift-keying
Authors: Lin You-Cheng , Hu Kuan-Wei , Huang Hsing-Yi , Yang Yueh-Hsun , Wang You-Xin , Hsu Shih-Chang , Cheng Chih-Hsien , Matsumoto Atsushi , Akahane Kouichi , Wu Yuh-Renn , Kuo Hao-Chung , Lin Gong-Ru
Published: December 2024

An adaptive differential-phase-shifting (DPS) quantum key distribution (QKD) protocol improved by encoding asynchronous-bit-rate with harmonic clock tunability, decoded by shortened delay-line interferometer (DLI) with enhancing stability, and received by single-photon detection with long hold-off is demonstrated to realize low-erroneous transmission. To achieve long-term stabilized visibility with a maintained quantum bit-error-ratio (QBER) and secure key rate, the shortened and polarized DLI enlarges its free-spectral range (FSR) and reduces its power-to-wavelength slope (δP/δλ) to suppress its sensitivity to thermal gradient, channel leakage, and wavelength disturbance. Extremely low power and wavelength drifts of ΔP/P < ±0.02% and Δλ/λ = ±6.45 × 10−8 can be achieved, even when using a single-mode QKD carrier with a relatively broadened 300-kHz linewidth. Flexibly expanding the 1-bit-delay FSR of the polarized DLI from 0.04 to 1.00 GHz improves its immunity to environmental disturbances, enabling the DPS-QKD decoding with 210–213 patterns, 3.2% QBER, and 17.46-kbit/s under 0.22 photon/pulse in average. The asynchronous-bit-rate DPS-QKD protocol enables harmonic expansion of DLI’s FSR at limited single-photon avalanche detector’s bit rate, which lengthens the duration of stable visibility to support long-pattern DPS-QKD.
P-type electrical transport properties and excellent Hall mobility of GaSb single crystal grown by Ga flux
Authors: Zhao Yu , Pan Yongqiang , Chen Li , Cheng Ming , Liu Lanxin , Zhang Lei , Zhang Ranran , Zhu Xiaoguang , Song Wenhai , Luo Xuan , Sun Yuping
Published: December 2024

Semiconductor materials, especial the Gallium antimonide (GaSb), have many unique properties and potential application, which attracted significant research interest. However, GaSb single crystal always shows a lower mobility due to the intrinsic defects, which greatly limits its application in electronic and optoelectronic devices. Here, GaSb single crystal has been grown by the Ga as the self-flux method. The properties of temperature dependent structure and surface morphology have been systematically investigated. The temperature dependent vibration modes of longitudinal optical and transverse optical were studied with Raman spectra. The thermal conductivity and thermoelectric measurements were on GaSb single crystal. The thermoelectric results revealed the Seebeck coefficient (S) is 552 μV/K at 300 K, which is conducive to thermoelectric property. The electrical resistivity and Hall coefficient display semiconducting behaviors with energy gaps of 34.5 and 29.2 meV, respectively. In particular, the Hall mobility reaches 1066 cm2/V·s at 300 K, which is superior than most of the GaSb single crystals grown by other methods. The mechanism of high Hall mobility related to the native defect concentration and dislocation density on the GaSb single crystal was discussed.
Type-n electrical activations of unintentionally
auto-doped N atoms in the CVD diamond films grown on the HPHT Ib substrates,
after 4-MeV Si2+ irradiations
Authors: Nakata Jyoji
Published: December 2024

This article describes observation of n-type conductivity for chemical vapor deposition (CVD) diamond films annealed by using 4-MeV Si2+ ion-beam irradiation at a low temperature of 660 °C. Although CVD diamond films grown on the High-Pressure High-Temperature (HPHT) Ib-substrates showed excellent crystallinity, these films were unintentionally auto-doped with highly concentrated N atoms. At first, n-type conductivity had not been judged for the as-grown state. However, after irradiation by 4-MeV Si2+ ions at 660 °C, the grown diamond film exhibited clear and stable n-type conductivity at a relatively low temperature of 250 °C. This fact was ascertained by measuring the electrical conductivity with a Hall effect apparatus. The as-purchased HPHT Ib-substrate after a normal RCA cleaning processes exhibited evident n-type conductivity at above 300 °C due to intrinsically contained dopant N atoms in the substrate. On the other hand, the as-grown CVD film deposited on the Ib-substrate exhibited evident n-type conductivity at a thoroughly lower temperature of 250 °C after 4-MeV Si2+ irradiation. 250 °C temperature is lower than 300 °C for the as-purchased HPHT Ib-substrate. Theoretical simulations were performed to fit Hall-measured data of sheet resistivity and sheet carrier concentration. The simulation results were based on the charge neutrality principles. The author also proposed novel activation energy of N atoms in diamond semiconductors to be 2.5 eV, which is much larger than formerly reported values of 1.4–1.7 eV. Lastly, the author discussed the possibility of MeV-ion irradiations being as novel and useful annealing technology for heavy type-n-dopants ion implantations into diamond semiconductors.
Design of soft x-ray high diffraction efficiency and spectral flux Au/Ni bilayer coated laminar-type diffraction grating for objective soft x-ray flat-field spectrograph in a region of 250–550 eV
Authors: Koike M. , Hatano T. , Pirozhkov A. S. , Murano T. , Oue Y. , Koshiya S. , Kakio T. , Kondo K. , Terauchi M.
Published: December 2024

An objective soft x-ray flat-field spectrograph employing a laminar-type bilayer coated, varied-line-spacing, spherical grating was designed to improve the detection limit and sensitivity of soft x-ray flat-field spectrographs in a region of 250–550 eV. As a design criterion, spectral flux, SF, [Hatano et al., Appl. Opt. 60, 4993–4999 (2021)], which is proportional to the amount of optical flux incident onto a detector and correlated with detection sensitivity, was used to be maximized. To enhance reflectivity with the coating design, Au/Ni bilayer coating was investigated to optimize the incidence angle and thickness of the Ni layer. This is based on the consideration that, in an energy region of over 400 eV, refractive indices of Au (bottom layer), Ni (top layer), and vacuum are increased from the bottom to the top of the layers, and a supplemental enhancement of reflectivity can be expected by optimizing the thickness of the top layer. Thus, the thickness of Ni and the incidence angle were chosen to be 8.0 nm and 86.00°, respectively. To maintain dispersion and spectral resolution of the grating used at an incidence angle of 87.07° as previously designed, groove density was increased to 1500 lines/mm from 1200 lines/mm of our previous design. Finally, a holographic, varied-line-spacing, spherical grating was designed assuming an aspherical-wavefront-recording configuration. The numerical simulation results showed that the spectrograph employing newly designed grating with laminar-type grooves and Au/Ni bilayer coating exhibited 2–18 times higher spectral flux as well as an improved spectral resolution compared with those obtained with the previously designed gratings and spectrographs.
Thermal enhancement of defect motion for optimizing periodic poling of x-cut thin-film lithium niobate
Authors: Doshi Sagar P. , West Gavin N. , Gray Dodd , Ram Rajeev J.
Published: December 2024

Patterning of stable, spatially tailored ferroelectric domains in thin-film lithium niobate enables efficient nonlinear optical interactions through quasi-phase matching. The engineering of domain structure is limited by the uncontrolled distribution of defects, which disrupt domain wall motion. Here, we fabricate quasi-phase matching gratings in thin-film lithium niobate with sub 20 nm of period variation. We demonstrate that annealing processed samples at 350 or 500 °C for 48 h, prior to E-field poling, can dramatically reduce the duty cycle variation. We show that maintaining an elevated temperature of 200 °C during poling enhances defect mobility, which leads to more rectangular inverted domains. Moreover, poling at elevated temperatures also increases inversion depth without sacrificing the periodic domain pattern's accuracy or precision. Elevating the temperature prior to and during poling resulted in near-ideal square wave patterning of ferroelectric domains (50% mean duty cycle, sub 10% domain width variation, and 100% depth inversion). This enables effective quasi-phase matching for second harmonic generation in 5.6 mm-long waveguides fabricated from MgO-doped x-cut thin-film lithium niobate.
Copper catastrophic oxidation: Theory and mechanisms
Authors: Belousov Valery V.
Published: December 2024

Copper and its alloys with transition metals (as good conductors of electricity and heat) are extensively used in electrical industry, electronics, and cooling systems and can be the subject of surface degradation by oxidation. In certain circumstances, surface degradation of copper occurs catastrophically. Predicting catastrophic oxidation kinetics and developing protective technology require understanding the mass transfer mechanisms in the solid/liquid/gas composite scale formed on the copper surface during catastrophic degradation. However, these mechanisms are not clear enough. The role of capillary forces in the mass transport process in the composite scale with a high density of solid/liquid and liquid/gas interfaces has not been established. Here, we show the significant contribution of both electrochemical and solutocapillary forces to mass transfer and suggest the mechanisms, involving selective transport of ions, gas bubbles, and liquid, and their relationships with the microstructure of the composite scale. The bubble nucleation is discussed.
Effect of gas pressure on plasma asymmetry and higher harmonics generation in sawtooth waveform driven capacitively coupled plasma discharge
Authors: Sharma Sarveshwar , Turner Miles , Sirse Nishant
Published: December 2024

Using the particle-in-cell simulation technique, the effects of gas pressure (5–500 mTorr) on the plasma spatial asymmetry, ionization rate, metastable gas densities profile, electron energy distribution function, and higher harmonics generation are studied in a symmetric capacitively coupled plasma discharge driven by a sawtooth-like waveform. At a constant current density of 50 A/m2, the simulation results predict a decrease in the plasma spatial asymmetry (highest at 5mTorr) with increasing gas pressure reaching a minimum value (at intermediate gas pressures) and then turning into a symmetric discharge at higher gas pressures. Conversely, the flux asymmetry shows an opposite trend. At a low gas pressure, the observed strong plasma spatial asymmetry is due to high-frequency oscillation on the instantaneous sheath edge position near one of the electrodes triggered by a temporally asymmetric waveform, whereas the flux asymmetry is not present due to the collisionless transport of charge particles. At higher pressures, multistep ionization through metastable states dominates in the plasma bulk, causing a reduction in the plasma spatial asymmetry. Distinct higher harmonics (near 26th) are observed in the bulk electric field at a low pressure, which diminishes at higher gas pressures. The electron energy distribution function changes its shape from bi-Maxwellian at 5 mTorr to nearly Maxwellian at intermediate pressures, and then depletion of the high-energy electrons (below 25 eV) is observed at higher gas pressures. The inclusion of the secondary electron emission is found to be negligible on the observed simulation trend.
Voltage-induced magnetic domain evolution in a phase-change material
Authors: Chen Tian-Yue , Sasaki Dayne Y. , Achinuq Barat , Ghazikhanian Nareg , Salev Pavel , Ohldag Hendrik , Scholl Andreas , Schuller Ivan K. , Takamura Yayoi , Kent Andrew D.
Published: December 2024

Applying voltage to metal–insulator transition (MIT) materials allows electrical actuation of the local electronic phase state. In MIT systems that have the electronic order coupled with the magnetic order, voltage switching of the electronic phase state can also enable the electrical manipulation of magnetic properties. In this work, we utilized x-ray magnetic circular dichroism photoemission electron microscopy (XMCD-PEEM) to investigate the control of magnetic domain configurations in ferromagnetic MIT electrical switches. For applied voltages above a threshold value, the XMCD-PEEM images show that the magnetic domains separate into two distinct regions: one with a high contrast (white/black), indicating well-defined micrometer-scale magnetic domains with a component of their magnetization aligned parallel/antiparallel to the x-ray helicity, and the other with different shades of intermediate contrast (gray). Significant changes in magnetic domain configurations upon voltage biasing were only observed in these gray regions. Furthermore, the voltage-induced magnetic domain separation was found to be bias polarity-dependent, with the gray regions expanding from the opposite sample edge when the applied voltage polarity was reversed. This polarity-dependent electrical control of magnetic domain configurations during the MIT switching opens alternative opportunities in memory applications for magnetic MIT switching materials.
Experimental observation of ballistic to diffusive transition in phonon thermal transport of AlN thin films
Authors: Hoque Md Shafkat Bin , Koh Yee Rui , Zare Saman , Liao Michael E. , Huynh Kenny , Goorsky Mark S. , Liu Zeyu , Shi Jingjing , Graham Samuel , Luo Tengfei , Ahmad Habib , Doolittle W. Alan , Hopkins Patrick E.
Published: December 2024

Ultrawide bandgap semiconductor aluminum nitride (AlN) possesses high thermal conductivity in bulk form due to long phonon mean-free-paths, high group velocity, and long lifetimes. However, the thermal transport scenario becomes very different in a thin AlN film due to phonon-defect and phonon-boundary scattering. Herein, we report experimental observation of ballistic to diffusive transition in a series of AlN thin films (1.6–2440 nm) grown on sapphire substrates. The ballistic transport is characterized by constant thermal resistance as a function of film thickness due to phonon scattering by defects and boundaries. In this transport regime, phonons possess very small group velocities and lifetimes. A gradual increase in the optical phonon lifetime is observed in the diffusive regime. Our study will aid the incorporation of highly conductive thin film materials in the semiconductor production line for efficient thermal management.
Curvature structure triboelectric nanogenerator for harvesting human motion energy and cheerleading training monitoring
Authors: Wang Jing , Feng Anchao
Published: December 2024

Recently, self-powered wearable sports monitoring devices have garnered widespread attention. However, earlier sensor devices suffer from limitations such as single-mode operation, unstable output, and high power consumption. In this study, we leveraged the curvature effect to enhance the performance of triboelectric nanogenerators (C-TENGs) for harvesting micro-mechanical energy. The C-TENG demonstrated an open-circuit voltage (Voc) of 507.07 V, a short-circuit current (Isc) of 80.03 μA, and a transfer charge (Qsc) of 100.47 nC. Additionally, the C-TENG achieved a high output power of 3.22 mW with a 4 MΩ external resistor. Furthermore, a C-TENG sensor array embedded in shoes can monitor the cheerleading performer’s gait by analyzing the differences in signals from three C-TENG sensors. This includes detecting slow walking, brisk walking, and jumping. This innovative sensing design differs from previous single-signal outputs and effectively avoids sensing errors caused by sensor fatigue and loss.
Fano-modulated chiral metasurface for near-infrared sensing via bound states in the continuum
Authors: Raza Faizan , Chen Rui , Ma Yungui
Published: December 2024

We report a plasmonic–dielectric metasurface that offers dynamic control over chiroptical properties, adjustable Q-factors, and inter-band chirality manipulation through multiple symmetry-breaking mechanisms. By controlling chiral quasi-bound states in the continuum (BIC) modes and Fano resonances, we enable hybridized and independently tunable spectral responses, offering precise control over resonance amplitude, polarization sensitivity, and refractive index sensing with high flexibility. Chirality is induced by rotating silicon nanofins on a dielectric spacer with a gold backplate, enabling tunable chiroptical responses with controllable spectral linewidth and independent or simultaneous dual-wavelength band excitation. We report a novel phenomenon of controlling interplay of chirality between two closely positioned wavelength bands to tailor symmetry breaking for a specific resonant mode (chiral) while preserving symmetry for the other mode (achiral). Additionally, we report the phase-sensitive evolution of Fano resonance from pure reflectance dip when controlled by dielectric spacer height and further demonstrated phase-insensitive control of Fano resonance amplitude. We divided Fano resonance into a distinct spectral peak and dip to improve light manipulation within the metasurface. Our proposed sensor demonstrates sensitivity and a quality factor of about 435 nm/RIU and 3888, respectively. Furthermore, we compared different phenomena (chiral selectivity, quasi-BIC, Fano) and sensing parameter values for different metasurface configurations (including single nanofin and absence of a spacer) and observed that the configuration without a spacer achieved the highest sensitivity of approximately 640 nm/RIU.
Molecular beam epitaxy of superconducting zirconium nitride on GaN substrates
Authors: May Brelon J. , Regmi Sabin , Khanolkar Amey R. , Buturlim Volodymyr , Cresswell Zachery E. , Vallejo Kevin D. , Gofryk Krzysztof , Hurley David H.
Published: December 2024

Epitaxial integration of metals and semiconductors can enable enhanced performance and novel functionality. Achieving such pristine interfaces with superconducting materials is of increasing interest for quantum devices and detectors, but the experimental demonstration remains challenging, given the very limited studies on single crystalline systems. To expand the potential materials for these systems, this work explores the deposition of zirconium nitride superconducting thin films on GaN substrates at various temperatures using molecular beam epitaxy. A general trend of decreasing superconducting critical temperature is observed as the deposition temperature is reduced. The optical properties reveal a transition from metallic to dielectric behavior with colder deposition. The plasma frequency of the metallic films is also observed to be a function of growth temperature. These results pave the way for the integration of a highly tunable metal nitride with a well-established semiconductor system.
Applicability criteria of proper charge neutrality and special relativistic MHD models extended by two-fluid effects
Authors: Yoshino Shuntaro , Hirota Makoto , Hattori Yuji
Published: December 2024

The applicability of relativistic magnetohydrodynamics (RMHD) and its generalization to two-fluid models (including the Hall and inertial effects) is systematically investigated by using the method of dominant balance in the two-fluid equations. Although proper charge neutrality or quasi-neutrality is the key assumption for all MHD models, this condition is difficult to be met when both relativistic and inertial effects are taken into account. The range of application for each MHD model is illustrated in the space of dimensionless scale parameters. Moreover, the number of field variables of relativistic Hall MHD (RHMHD) is shown to be greater than that of RMHD and Hall MHD. Nevertheless, the RHMHD equations may be solved at a lower computational cost than RMHD in the limit of cold plasma, since root-finding algorithm, which is the most time-consuming part of the RMHD code, is no longer required to compute the primitive variables.
Iron redox effect on the structure and viscosity of a sodium silicate glass and melt
Authors: Sukenaga Sohei , Cicconi Maria Rita , Yamada Hiroki , Wakihara Toru , Ohara Koji , Shibata Hiroyuki , Neuville Daniel R.
Published: December 2024

The viscosity of silicate melts is one of the most important physical properties for understanding high-temperature phenomena in magmatic systems and material processing. The effects of composition and temperature on viscosity have long been elucidated. Although iron ions are the main components of magmatic systems, their influence on viscosity remains unclear because the behavior of iron is complicated; iron ions have two redox states, Fe3+ and Fe2+. Here, we elucidate the viscosity of an iron-sodium-silicate system with a variety of iron redox states at temperatures close to its glass transition temperature (Tg). The redox states and structures of the samples were characterized using x-ray absorption near-edge structure (XANES) spectroscopy, Raman spectroscopy, synchrotron x-ray total scattering, and density (molar volume) measurements. The viscosity increased (by more than four orders of magnitude) with an increase in the ratio of Fe3+ to total Fe (Fe3+/Fetot), whereas the temperature dependence of the viscosity was larger for glasses with a higher Fe3+/Fetot ratio at temperatures close to the glass transition temperature. The tendencies in viscosity and structural variation against the Fe3+/Fetot ratio support the consensus on the structural roles of Fe3+ and Fe2+ from previous studies: Fe3+ ions have a stronger tendency to behave as network formers than Fe2+ ions.
Preparation of biocrude based on fish proteins and lipids as feedstock by subcritical hydrothermal liquefaction
Authors: Qin Junjie , Wang Yan , Wei Qinhong , Chen Yong , Yang Shuqing , Zheng Xianmin
Published: December 2024

The fact that aquatic product waste causes environmental pollution and is difficult to handle has become a major challenge globally. Hydrothermal liquefaction (HTL) has provided new ideas for addressing this challenge. In this study, small yellow croaker was used as the raw material for HTL. It was found that the transition temperature point R from P1 (liquefied but without biocrude production) to P2 (biocrude production) lies between 200 and 250 °C. The impact of the pyrolysis temperature on the physical properties and composition of the produced biocrude was examined. The results showed that as the temperature increased, the acidity and density of the biocrude decreased. Furthermore, gas chromatography–mass spectrometry (GC-MS) analysis identified the components, revealing that changes in the physical properties were closely related to changes in the chemical composition. Although the composition remained similar with increasing temperature, the content varied significantly: the content of fatty acids and their derivatives decreased markedly, whereas that of aromatic compounds increased significantly. At 300 °C, the carbon chain distribution of the compounds was notably lower, with most being light oils, resulting in a reduced viscosity and density of the biocrude. Additionally, GC-MS analysis explored the effect of residence time on biocrude quality and found that reaction conditions of 300 °C for 125 min yielded high-quality biocrude and showed great potential for quality improvement with the addition of catalysts. Moreover, by altering the temperature and residence time, the content of the products can be controlled to produce high-value-added products.
Exploring magnetism, topology, and magnetoresistance in rare-earth-based compound GdAuSn: Ab initio study
Authors: Mondal Sumit , Singh Jaspreet , Kanchana V.
Published: December 2024

Rare-earth intermetallics, especially Gd-based compounds, are of great interest due to their diverse magnetic ground states and intriguing topological properties. Using first-principles calculations, we investigate the magnetic, electronic, and phononic properties of GdAuSn. Our results identify the C-type antiferromagnetic configuration as the lowest energy state, with a critical temperature of 25 K estimated using the Heisenberg spin model and mean-field approximation. The electronic band structure reveals nodal surfaces and Dirac points, highlighting the material’s non-trivial topology. In the magnetically ordered state, GdAuSn exhibits positive transverse magnetoresistance, increasing to ∼25% at 3.5 T and 10 K, with Hall resistivity analysis confirming electron-dominated transport. Additionally, phonon dispersion analysis uncovers topological phononic states with nodal surfaces. These findings provide insights into the interplay of magnetism, topology, and transport in GdAuSn, establishing its potential for fundamental research and topological antiferromagnetic spintronics.
Robust dark-field signal extraction for modulation-based x-ray tensor tomography
Authors: Lautizi Ginevra , Di Trapani Vittorio , Studer Alain , Zdora Marie-Christine , De Marco Fabio , Kim Jisoo , Marone Federica , Stampanoni Marco , Thibault Pierre
Published: December 2024

We demonstrate a robust signal extraction method for x-ray speckle-based tensor tomography. We validate the effectiveness of the method for several carbon fiber composites, highlighting its potential for industrial applications. The proposed method can be adapted to various acquisition schemes and wavefront-marking optical elements, making it a versatile and robust tool for x-ray scattering tensor tomography.
Highly stretchable, electrochemical capacitance, and transparent supercapacitor based on serpentine-structured metallic mesh current collector
Authors: Jiang Zhouying , Zhao Yaoyao , Liu Yanhua
Published: December 2024

Transparent and stretchable energy storage devices, maintaining the capability of steady operations under harsh conditions, have gained more importance with the development of transparent and stretchable electronics devices. Highly stretchable and transparent supercapacitors are essential for next-generation energy-storage systems with confluent high transparency, electrochemical stability, and mechanical properties during deformation processing. In this work, we report a transparent, flexible, and stretchable solid-state supercapacitor device with a serpentine-structured MnO2–Au–Ni mesh and a commercialized very high bond (VHB) tape; the stretchability of the hybrid electrode-based supercapacitor is significantly improved by shrinking the metallic mesh patched onto the VHB tape with pre-strain. The as-fabricated device exhibits an electrochemical capacitance of 3.64 mF/cm2 and an optical transparency of 73.63% at 300% strain. Furthermore, the device maintains 90.6% retention with strains up to 300% and 81.2% capacitance retention after 500 repeated stretch–release cycles at strains of 0%–300%. Along with the excellent tolerance to high deformation, the as-fabricated device can burden the desire for further wearable electronics.
Numerical study on the transient dynamics and film cooling effect in a non-premixed cylindrical rotating detonation engine
Authors: Yu Jingtian , Yao Songbai , Li Jianghong , Lei Ying , Zhou Yeqi , Guo Chunhai , Zhang Wenwu
Published: December 2024

This study presents a three-dimensional numerical analysis of a cylindrical rotating detonation engine (RDE) utilizing a non-premixed injection scheme, in which the gaseous fuel is injected from the outer periphery toward the center through a slit-orifice injection system. The investigation explores the ignition process, transient behavior, and the structure of the rotating detonation wave (RDW) under varying mass flow rates. Additionally, the influence of the film cooling jets is analyzed in the current non-premixed RDE, where three different types of complex-shaped film cooling holes are considered and compared. At a low air flow rate of 100 g/s, the detonation flow field exhibits frequent combustion instabilities, including RDW intensity attenuation, quenching, and re-ignition due to self-ignition in the fuel refill region. These instabilities result in transitions between single-wave, dual-wave, and quenching states. At an air flow rate of 200 g/s, a stable single-wave mode is observed; however, the RDW shape fluctuates, alternating between elevated, stratified, inclined, and diminished wave front patterns. As the air flow increases to 300 g/s and 400 g/s, the RDW stabilizes into a dual high-pressure region with an approximate 40° forward inclination. When film cooling is introduced, although the RDW's structure remains stable, the cooling air jet alters fuel mixing, leading to low hydrogen mass fractions and affecting local equivalence ratios.
Functionally conserved inner mitochondrial membrane proteins CCDC51 and Mdm33 demarcate a subset of fission events
Authors: Edington Alia R. , Connor Olivia M. , Love Abigail C. , Marlar-Pavey Madeleine , Friedman Jonathan R.
Published: December 2024

While extensive work has examined the mechanisms of mitochondrial fission, it remains unclear whether internal mitochondrial proteins in metazoans play a direct role in the process. Previously, the yeast inner membrane protein Mdm33 was shown to be required for normal mitochondrial morphology and has been hypothesized to be involved in mitochondrial fission. However, it is unknown whether Mdm33 plays a direct role, and it is not thought to have a mammalian homolog. Here, we use a bioinformatic approach to identify a structural ortholog of Mdm33 in humans, CCDC51 (also called MITOK), whose depletion phenocopies loss of Mdm33. We find that knockdown of CCDC51 also leads to reduced rates of mitochondrial fission. Further, we spatially and temporally resolve Mdm33 and CCDC51 to a subset of mitochondrial fission events. Finally, we show that CCDC51 overexpression promotes its spatial association with Drp1 and induces mitochondrial fragmentation, suggesting it is a positive effector of mitochondrial fission. Together, our data reveal that Mdm33 and CCDC51 are functionally conserved and suggest that internal mitochondrial proteins are directly involved in at least a subset of mitochondrial fission events in human cells.
Synaptic sabotage: How Tau and α-Synuclein undermine synaptic health
Authors: Uytterhoeven Valerie , Verstreken Patrik , Nachman Eliana
Published: December 2024

Synaptic dysfunction is one of the earliest cellular defects observed in Alzheimer’s disease (AD) and Parkinson’s disease (PD), occurring before widespread protein aggregation, neuronal loss, and cognitive decline. While the field has focused on the aggregation of Tau and α-Synuclein (α-Syn), emerging evidence suggests that these proteins may drive presynaptic pathology even before their aggregation. Therefore, understanding the mechanisms by which Tau and α-Syn affect presynaptic terminals offers an opportunity for developing innovative therapeutics aimed at preserving synapses and potentially halting neurodegeneration. This review focuses on the molecular defects that converge on presynaptic dysfunction caused by Tau and α-Syn. Both proteins have physiological roles in synapses. However, during disease, they acquire abnormal functions due to aberrant interactions and mislocalization. We provide an overview of current research on different essential presynaptic pathways influenced by Tau and α-Syn. Finally, we highlight promising therapeutic targets aimed at maintaining synaptic function in both tauopathies and synucleinopathies.
Directed stochasticity: Building biomolecular condensates in the right place
Authors: Geisler Mark S. , Kemp James P. , Duronio Robert J.
Published: December 2024

Controlling biomolecular condensate formation within the nucleus is critical for genome function. In this issue, Xu et al. (https://doi.org/10.1083/jcb.202401036) report that KPNA3 promotes histone locus body formation and expression of replication-dependent histone genes by both importing NPAT into the nucleus and preventing NPAT condensation from improperly occurring in the cytoplasm.
Differential impact of lymphatic outflow pathways on cerebrospinal fluid homeostasis
Authors: Papadopoulos Zachary , Smyth Leon C.D. , Smirnov Igor , Gibson Daniel A. , Herz Jasmin , Kipnis Jonathan
Published: December 2024

Dysfunctional lymphatic drainage from the central nervous system (CNS) has been linked to neuroinflammatory and neurodegenerative disorders, but our understanding of the lymphatic contribution to CNS fluid autoregulation remains limited. Here, we studied forces that drive the outflow of the cerebrospinal fluid (CSF) into the deep and superficial cervical lymph nodes (dcLN and scLN) and tested how the blockade of lymphatic networks affects CNS fluid homeostasis. Outflow to the dcLN occurred spontaneously in the absence of lymphatic pumping and was coupled to intracranial pressure (ICP), whereas scLN drainage was driven by pumping. Impaired dcLN drainage led to elevated CSF outflow resistance and delayed CSF-to-blood efflux despite the recruitment of the nasal-to-scLN pathway. Fluid regulation was better compensated after scLN obstruction. The dcLN pathway exhibited steady, consistent drainage across conditions, while the nasal-to-scLN pathway was dynamically activated to mitigate perturbances. These findings highlight the complex physiology of CSF homeostasis and lay the groundwork for future studies aimed at assessing and modulating CNS lymphatic function.
Bilateral comparison of 1.018 V and 10 V standards between the NSAI (Ireland) and the BIPM, May to June 2024 (part of the ongoing BIPM key comparison BIPM.EM-K11.a and b)
Authors: Solve S , Chayramy R , Stock M , Power O , Prendergast S
Published: December 2024

Main text

As part of the ongoing BIPM key comparison BIPM.EM-K11.a and b, a comparison of the 1.018 V and 10 V voltage reference standards of the BIPM and the National Standards Authority of Ireland, National Metrology Laboratory (NSAI-NML), Dublin, Ireland, was carried out from May to June 2024. Two BIPM Zener diode-based travelling standards (Fluke 732B), BIPM_B (ZB) and BIPM_C (ZC), were transported by freight to NSAI-NML and back to BIPM. At the NSAI-NML, the reference standard for DC voltage is a Programmable Josephson Voltage Standard (PJVS). The output electromotive force (EMF) of each travelling standard was measured by direct comparison with the primary standard.

At the BIPM, the output EMF of each travelling standard was calibrated before and after the measurements at the NSAI-NML against the PJVS developed at the BIPM around a PTB programmable SNS Josephson junctions (Superconductor/Normal Metal/Superconductor) array.

Results of all measurements were corrected by the BIPM for the dependence of the output voltages of the Zener standards on internal temperature and ambient atmospheric pressure.

The final result of the comparison is presented as the difference between the values assigned to DC voltage standards by NSAI-NML, at the level of 1.018 V and 10 V, at NSAI-NML, UNSAI-NML, and those assigned by the BIPM, at the BIPM, UBIPM, at the reference date of the 28th of May 2024.

UNSAI-NML - UBIPM = -0.20 V; uc = 0.08 V, at 1.018 V

UNSAI-NML - UBIPM = -0.02 V; uc = 0.13 V, at 10 V

where uc is the combined standard uncertainty associated with the measured difference, including the uncertainty of the realization of the volt at the BIPM and at NSAI-NML, based on KJ, and the uncertainty related to the comparison.

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.

The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Gyroscopic gravitational memory from quasi-circular binary systems
Authors: Faye Guillaume , Seraj Ali
Published: December 2024

Gravitational waves cause freely falling spinning objects to precess, resulting in a net orientation change called gyroscopic memory. In this paper, we will consider isolated gravitational sources in the post-Newtonian (PN) framework and compute the gyroscopic precession and memory at leading PN orders. We compare two competing contributions: the spin memory and the nonlinear helicity flux. At the level of the precession rate, the former is a 2PN oscillatory effect, while the latter is a 4PN adiabatic effect. However, the gyroscopic memory involves a time integration, which enhances subleading adiabatic effects by the fifth power of the velocity of light, leading to a 1.5PN memory effect. We explicitly compute the leading effects for a quasi-circular binary system and obtain the angular dependence of the memory on the celestial sphere.
Fabrication of strain-sensing fibers with silver nanoparticles and reduced graphene oxide via wet spinning
Authors: Liu Xiaoyuan , Xu Qiuyu , Zhang Xuepeng , Jiang Wei , Li Junmei , Pan Runan , Song Ruochen , Liu Lifang
Published: December 2024

To advance the industrialization of flexible strain sensors, an innovative flexible sensing fiber was developed through a sophisticated wet spinning process. Silver trifluoroacetate and graphene oxide (GO) were combined with thermoplastic polyurethane (TPU) to prepare the fibers via wet spinning. Ascorbic acid was used to in situ reduce the silver trifluoroacetate and graphene oxide within the polyurethane, causing the growth of silver nanoparticles to bond with reduced graphene oxide, forming a dual conductive pathway. This resulted in the creation of silver nanoparticles/reduced graphene oxide/polyurethane fibers (AgNPs-rGO-TPU sensing fibers). The tensile and sensing properties of AgNPs-rGO-TPU sensing fibers under different parameters were investigated. The results showed that with 25 wt% TPU as the matrix, 30 wt% silver trifluoroacetate, and 1 wt% graphene oxide, the fibers achieved an optimal balance of mechanical and sensing properties. The tensile strength was 7.69 MPa, the elongation at break was 370.75%, and the toughness modulus was 18.45 MJ m−3. The AgNPs-rGO-TPU sensing fibers effectively detect external stimuli, exhibiting high sensitivity over a wide strain range (gauge factor is 4.25 below 5% strain, 24.79 in the 5%–25% strain range, 23.06 in the 25%–80% strain range, and 21.32 in the 80%–110% strain range), with a conductivity of 163.17 ms·cm−1. They can stably recognize movements and physiological signals from various parts of the human body, showing good application prospects.
A triboelectric sensor with an inverted pendulum design for machine and human movement monitoring in freestanding mode
Authors: Wong Kwong Long , Goh Qi Lun , Tan Chun Hui , Lim Eng Hock , Chee Pei Song
Published: December 2024

The vast availability of ambient mechanical vibrations in the natural environments and our daily activities has spurred the advancement of triboelectric sensors for vibration sensing. However, the operation of the traditional triboelectric vibration sensors (VSs) is usually constrained to contact–separation mode, limiting their functionality to transverse vibrations and making them unsuitable for longitudinal and rotary movements. The inherent wear and tear associated with the contact–separation mode further restricts their practical application. To address these limitations, this study presents a new design for a VS that employs a spring-assisted inverted pendulum structure. The VS exhibits a 10 Hz resonant frequency and produces maximum triboelectric output at the vibration amplitude of 5 mm. As a proof of concept, the VS successfully detects balanced and unbalanced fan blades by analyzing the obtained data via fast Fourier transform analysis. Besides machine monitoring, the proposed VS can be integrated into a wearable device for tracking human wrist movements. Combined with a machine learning algorithm, the sensor has achieved an accuracy level of greater than 95% in recognizing four distinct wrist motions: bending, rotating, waving, and handshaking. These findings have proven that the proposed triboelectric sensor design can be effectively integrated into wearable technologies, smart factories, and virtual/augmented reality systems, significantly broadening the triboelectric sensor applications.
A constitutive artificial neural networks-based mechanical model of the pneumatic artificial muscles
Authors: Wang Shuopeng , Wang Rixin , Ma Binwu , Zhang Ying , Hao Lina
Published: December 2024

Pneumatic artificial muscles (PAMs), recognized as typical smart material actuators, have perennially presented a formidable challenge in the realm of precise mechanical modeling due to the hyperelasticity and nonlinearity. In order to construct the mechanical model of the PAM, we propose a constitutive artificial neural network-based mechanical model. Utilizing the constitutive artificial neural network (CANN), we have constructed a strain energy function for PAMs that satisfies symmetry, objectivity, and polyconvexity. Furthermore, by employing the principle of virtual work and considering the hyper-elastic material, the geometric constraints, and the deformation of the internal air chamber, we have derived the mechanical model of PAMs. To verify the accuracy of the proposed model, the finite element simulation is used to demonstrate the modeling accuracy under different load conditions for PAMs with different geometries and constitutive model conditions. Finally, the accuracy and generalization of the proposed model is validated through experiments on a PAM experimental platform.
Ion-molecule reactions in CO2 clusters induced by low-energy electron attachment
Authors: Fan Mengyuan , Liu Jiayi , Tang Guoqiang , Tian Shan Xi
Published: December 2024

Dissociative electron attachment (DEA) process in molecular clusters is inherently complex, and elucidating the underlying mechanisms presents significant challenges. This study builds upon our previous research by investigating DEA in the larger and more numerous CO2 clusters, and extending the electron attachment energy to 15 eV. This enhanced approach allows for the detection of anionic species such as O

2

−

and (CO2)nO

2

−

. We recorded the production efficiency curves and kinetic energy distributions of the fragment anions, revealing that the O

2

−

anions can be formed via the DEA process of CO2 monomers, consistent with previously reported observations. Additionally, O

2

−

may also be produced through a cascade reaction process involving ion-molecule/atom interactions within the clusters, even when the attachment energy exceeds the DEA threshold of O

2

−

production from CO2 monomers. Furthermore, the stabilization of these detected anions (CO2)nO

2

−

is attributed to energy dissipation via molecular evaporative cooling, as previously proposed. This study offers new insights into the underlying mechanisms of DEA in molecular clusters, thereby enhancing our understanding of electron-induced reactions in atmospheric and astrochemical contexts.
Analysis on sensitivity and imperfect interfaces on the propagation of inter-facial anti-plane waves on the finely coated piezomagnetic reinforced composite structure
Authors: Singh Abhishek Kumar , Singh Pratiksha
Published: December 2024

Surface acoustic waves are pivotal in modern technology due to their exceptional sensitivity and adaptability. The motivation for this study stems from the need to enhance the efficiency of surface wave sensors by advancing mass loading techniques and addressing the imperfections that can alter the magneto-mechanical properties, velocities, and propagation behavior of anti-plane waves in layered composite structures. The present work analyses the propagation behavior of Love-type and B-G-type waves in a piezomagnetic fiber-reinforced composite (PMFRC) structure underlying an Air medium (in Model-1) and under a coated thin filmed mass loading (in Model-2) in the presence of distinct inter-facial imperfections viz. Mechanically compliant magnetically weakly permeable (MCMWP), Mechanically compliant magnetically highly permeable (MCMHP), Low magnetic permeable (LMP), Magnetically grounded (MG), and welded. These inter-facial imperfections have been considered as five different submodels under both Model-1 and 2. At first, the micromechanical model of PMFRC has been developed, and closed-form expression for the material constants has been derived by harnessing the techniques of strength of materials and the rule of mixtures. Employing the suitable boundary conditions associated with distinct five inter-facial imperfections, velocity equations have been derived, validated, and graphically demonstrated for both magnetic cases (open (MO) and short (MS)) under various submodels of both models. Magneto-mechanical coupling, mass loading sensitivity, volume fraction, and imperfect interfaces affecting the phase velocity of Love-type and B-G type waves have been analyzed with a comparative approach under various models and submodels. The outcomes of the study can enhance detection capabilities in SAW devices, broadening their use in telecommunications, aerospace, and other industries.