bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular dynamics insights into the dynamical behavior of structurally modified water in aqueous deep eutectic solvents (ADES)
Authors: Sil Arnab , Sangeeta  , Poonia Vishnu , Das Suman , Guchhait Biswajit
Published: October 2024

Recent studies have demonstrated that the presence of water in deep eutectic solvents (DESs) significantly affects their dynamics, structure, and physical properties. Although the structural changes due to the addition of water are well understood, the microscopic dynamics of these changes have been rarely studied. Here, we performed molecular dynamics simulation of 30% (v/v) (∼0.57 molar fraction) water mixture of DES containing CH3CONH2 and NaSCN/KSCN at various salt fractions to understand the microscopic structure and dynamics of water. The simulated results reveal a heterogeneous environment for water molecules in aqueous DES (ADES), which is influenced by the nature of the cation. The diffusion coefficients of water in ADESs are significantly lower than that in neat water and concentrated aqueous NaSCN/KSCN solution. When Na+ ions are replaced by K+ ions in the ADES system, the diffusion coefficient increases, which is consistent with the measured nuclear magnetic resonance data. Self-dynamic structure factor for water and other simulated dynamic quantities, such as reorientation, hydrogen-bond, and residence time correlation functions, show markedly slower dynamics inside ADES than in the neat water and aqueous salt solution. Moreover, these dynamics become faster when Na+ ions in ADES are replaced by K+ ions. The results suggest that the structural environment of water in Na+-rich ADES is rigid due to the presence of cation-bound water and geometrically constrained water. The medium becomes less rigid as the KSCN fraction increases due to the relatively weaker interaction of K+ ions with water than Na+ ions, which accelerates the dynamical processes.
C-type two-thermocouple sensor design between 1000 and 1700 °C
Authors: Guo Yangkai , Zhang Zhijie , Li Yanfeng , Wang Wenzhuo
Published: October 2024

At the present stage of transient ultra-high-temperature energy release of boron-containing warm-pressure explosives, single thermocouples are often used for multi-point measurements in the process of their temperature field changes, and the results of their temperature field reconstruction are not satisfactory due to the limited consistency of the thermocouples. Aiming at the above-mentioned problems, a C-type two-thermocouple suitable for transient temperature measurement in high-temperature environments is designed; the system characterization of the two-thermocouple is carried out by using the blind system identification method of the inter-relationships; the identification process is evaluated by a new cost function; and the optimal solution on the new cost function is realized by using the gradient descent method. The temperature reconstruction of the two-thermocouple output excited by the simulated heat source is carried out by using the auto-regressive with extra inputs model, and the feasibility of the reconstruction results is verified. In the experimental part, a thermocouple dynamic characteristic calibration system based on a high-temperature furnace is constructed and experimental validation is carried out in the high-temperature furnace to compare the effects of different exposure lengths and different wire diameters on the output of the two-thermocouple, and as a result, the outputs are corrected and analyzed. The results show that two-thermocouple methods with different combinations of wire diameters are better for temperature measurement, with a reconstructed root mean squared error of 0.0162 and a goodness of fit of 89.13%.
Exploring anti-ferroelectric thin films with high energy storage performance by moderating phase transition
Authors: Zhang Tianfu , Si Yangyang , Li Xudong , Li Yijie , Wang Tao , Zhang Qinghua , Tang Yunlong , Chen Zuhuang
Published: October 2024

Anti-ferroelectric thin films are renowned for their signature double hysteresis loops and sheds light on the distinguished energy storage capabilities of dielectric capacitors in modern electronic devices. However, anti-ferroelectric capacitors are still facing the dual challenges of low energy density and efficiency to achieve state-of-the-art performance. Their large hysteresis and sharp first-order phase transition usually results in a low energy storage efficiency and easy breakdown, severely obscuring its future application. In this study, we demonstrate that anti-ferroelectric (Pb0.97La0.02)(Zr1−xSnx)O3 epitaxial thin films exhibit enhanced energy storage performance through local structural heterogeneity to moderate the first-order phase transition by calculating the corresponding polarization as a function of switching time for the first time. The films exhibit remarkable enhanced breakdown strength (∼3.47 MV/cm, ∼5 times the value for PbZrO3) and energy storage performance. Our endeavors have culminated in the ingenious formulation of a novel strategy, namely, the postponement of polarization processes, thereby elevating the breakdown strength and total energy storage performance. This landmark achievement has unveiled a fresh vista of investigative opportunities for advancing the energy storage prowess of electric dielectrics.
Mesoporous La0.8Sr0.2CoO3/H-COK-12 catalyst synthesized by template method: Highly active for the complete oxidation of CO
Authors: Wang Xuefang , Chen Jieming , Li Chunhui , Liu Pan , Zha Xiaoqin
Published: October 2024

Using cheap sodium silicate as a silica source and surfactant P123 as a soft template, an environment-friendly mesoporous material, COK-12, was prepared in a near-neutral environment. COK-12 was modified with n-hexane to obtain an H-COK-12 template with a compact and ordered pore structure. In this study, the modified mesoporous material H-COK-12 was used as the template for the first time, and the mesoporous La0.8Sr0.2CoO3 (LSC) catalyst was prepared by nano-casting method combined with sol–gel method. The results showed that the LSC-650 catalyst synthesized at 650 °C for 2 h possessed a large specific surface area (103.46 m2/g) and the highest surface Co4+/Co3+ and Oads/Olat molar ratio. In addition, the CO conversion with the LSC-T (T = 550, 600, 650, 700 °C) samples indicated that the LSC-650 sample had the best catalytic activity (T50 = 145 °C, T90 = 149 °C) and stability.
Bistability-enhanced elastocaloric cooling device based on a natural rubber foil
Authors: Ludwig Carina , Kohl Manfred
Published: October 2024

A novel solid-state elastocaloric cooling device is presented, making use of a bistable actuation mechanism for loading of a natural rubber (NR) foil refrigerant. The thicknesses of the foil refrigerants are 290 and 650 μm in an initial undeformed state, while their lateral size is 9 × 26.5 mm2. Owing to the large surface-to-volume ratio of the NR foils, heat transfer to the heat sink and source is accomplished by a solid–solid mechanical contact. The loading mechanism consists of a rotating lever arm providing for stable positions at contact to the heat sink and source, which allows for significant power saving during elastocaloric cycling. In addition, the negative biasing associated with bistability favors good thermal contact at the end positions, which improves heat transfer resulting in a maximum temperature span ΔTdevice of 4.2 K in the strain range of 300%–700% under adiabatic conditions. The coefficient of performance of the device COPdevice reaches values up to 5.7 for foil refrigerants of 290 μm thickness. The maximum cooling power is 214 mW corresponding to a specific cooling power of 3.4 Wg−1.
Non-Hermitian mode management in periodically modulated waveguide amplifiers
Authors: Akhter Mohammad Nayeem , Botey Muriel , Herrero Ramon , Staliunas Kestutis
Published: October 2024

We propose an efficient mode management scheme in active nonlinear multimode fibers based on non-Hermitian potentials in the longitudinal direction with an antisymmetric transverse profile. The proposal takes advantage of the nonlinear saturation toward particular mode configurations, which can be tuned by the non-Hermitian potential. We demonstrate flexible control of the beam profile within the parameter space of the applied potential with various possibilities, such as improving the beam quality by condensing photons to the lowest order Hermite mode, exciting higher order modes, or engineering a desired mode profile as a combination of modes. The effect is also analytically predicted using a mode-expansion approach, showing good agreement with the full model calculations based on the complex Ginzburg–Landau equation. This study was performed for 1D planar guiding structures, yet the results can be extended to 2D fibers and could be very useful in applications of fiber amplifiers and lasers.
Calculation of tearing mode stability in an inverse aspect-ratio expanded tokamak plasma equilibrium
Authors: Fitzpatrick Richard
Published: October 2024

The tearing mode stability of an inverse aspect-ratio expanded tokamak plasma equilibrium of general shape is investigated using asymptotic matching techniques. Particular emphasis is placed on the conservation of toroidal electromagnetic angular momentum. The TJ code, which is a specific implementation of the results of the investigation, is described.
A modular, low-field magnetic resonance design with pre-polarization for characterizing flows
Authors: Richard Sebastian J. , Newling Benedict , Balcom Bruce J.
Published: October 2024

We have recently demonstrated a magnetic resonance method using variable τ spin echoes to simultaneously determine both the average velocity and flow behavior index in a variety of pipe flows. In this work, we present a new, modular, low-field design built specifically for use with our methodology. The design is based on low-cost ceramic magnets. It consists of a sensor built using a pitched magnet arrangement in combination with several modular pre-polarizing units to facilitate a controlled pre-polarization length for measurements on flows that require a significant amount of time in a magnetic field to become polarized (e.g., aqueous solutions). Here, measurements made with this design are shown for a range of flow rates that span the laminar regime and into the turbulent regime.
Difference in structural changes of surfactant aggregates near solid surface under shear flow versus those in the bulk
Authors: Nemoto Fumiya , Takabatake Fumi , Yamada Norifumi L. , Takata Shin-ichi , Seto Hideki
Published: October 2024

In water, the nonionic surfactant pentaethylene glycol monododecyl ether (C12E5) forms multi-lamellar vesicles upon application of shear, attributed to buckling instability of the surfactant layers. In the standard setup for applying shear, a pair of solid substrates is moved in opposite directions, and a non-slip condition at the solid surface is assumed. Based on theoretical predictions, the effective viscosity of the fluid surrounding the membrane is modified in this process, and this confinement may affect membrane fluctuation. However, only a few studies have analyzed the structural changes near the substrate. From this viewpoint, the structural changes in surfactant aggregates near a solid substrate under the application of shear were investigated herein using neutron reflectometry (NR). By increasing the shear rate, shear thickening at a lower shear rate and shear thinning at a higher shear rate were observed, similar to that in the bulk. However, a discontinuous change in the lamellar structure accompanying the condensation of the surfactant was observed in the NR experiments. This study presents the first experimental evidence indicating that the ramping speed of shear rates governs the shear-induced structuring of surfactant aggregates near the surface.
Dispersion leading potential energy surface of N2·NbN12−: Anion photoelectron spectroscopy and theoretical studies
Authors: Liu Kai-Wen , Yang Bin , Wang Peng , Yan Shuai-Ting , Xu Xi-Ling , Xu Hong-Guang , Zheng Wei-Jun
Published: October 2024

In order to understand the dispersion interactions between molecules and to provide information about the potential energy surface of geometry evolutions, NbN12− and N2·NbN12− complexes were investigated by using photoelectron spectroscopy and ab initio calculations. The experimental adiabatic detachment energy (ADE) and vertical detachment energy (VDE) of NbN12− were both measured to be 2.129 ± 0.030 eV. The experimental ADE and VDE of N2·NbN12− were measured to be 2.17 ± 0.05 and 2.23 ± 0.05 eV, respectively, which are slightly higher than those of NbN12−. The structures of NbN12−/0 were confirmed to be hexacoordinated octahedrons. The investigation of N2·NbN12− structures shows that it is stable for N2 to bind to the face or vertex site of octahedron NbN12−; the face-side-on structure has the lowest energy. The calculations based on symmetry-adapted perturbation theory suggest that the dispersion term is predominant and leads to the stability of N2·NbN12− complexes.
Emulsion formation and stability of surfactant–polymer flooding
Authors: Li Jierui , Li Yalong , Liu Weidong , Cong Sunan , Zheng Kai , Li Anjing
Published: October 2024

Emulsification plays a pivotal role in the process of enhanced oil recovery, especially in chemical flooding. Surfactant–polymer flooding is a promising technique with significant potential for improving oil recovery in medium and high permeability oilfields in China. Emulsification has emerged as one of the key mechanisms facilitating oil recovery in surfactant–polymer flooding. This study aimed to assess the effects of surfactant structure and concentration, polymer, oil–water ratio, clay content, and injection rate on the formation of different emulsion types and their stabilities. The assessment was conducted based on the actual conditions of surfactant–polymer flooding in the Qizhong area of the Xinjiang oilfield. The findings revealed that KPS-1 (petroleum sulfonate) demonstrated superior emulsifying and solubilizing abilities for crude oil compared to BS-18 (betaine), whereas BS-18 exhibited better emulsifying stability. KPS, which was a combination system of KPS-1 and BS-18, displayed favorable emulsifying ability. However, the emulsifying stability of the three surfactants decreased in the presence of HPAM (hydrolyzed polyacrylamide). The oil–water ratio primarily influenced the morphology of the emulsion. When the oil–water ratio exceeded 6:4, a water-in-oil emulsion was formed, and the viscosity of the emulsion reached its maximum at an oil–water ratio of 7:3. Moreover, clay demonstrated a significantly high ability to emulsify, resulting in the formation of emulsions with increased viscosity and robust stability. Regarding the injection rate, effective emulsification occurred when the injection rate reached 1 m/d, while emulsions with high viscosity were observed at an injection rate of 7 m/d.
Study on the flame structure and flow field of hydrogen-enriched combustion in array micro-tube
Authors: Tian Liang , Feng Wenbin , Han Xiao , Liu Yuzhi , Liu Hongfang , Cai Xiao
Published: October 2024

Addressing climate change and reducing greenhouse gas emissions are critical priorities. Utilizing hydrogen-rich methane or pure hydrogen as fuels within gas turbines, facilitated by array micro-tube premixed combustion technology, is anticipated to markedly accelerate the decarbonization process of the energy sector. In this study, the flame structure of the array micro-tube premixed burner under various fuel compositions was examined using OH-Planar Laser-Induced Fluorescence and Particle Image Velocimetry measurement techniques. The effects of the equivalence ratio (φ) and the hydrogen power ratio (HPR) on the characteristics of the flame front, including its curvature, density, volume, and the associated flow field properties, were discussed. As φ and HPR increase, the wrinkled structure of the flame front is significantly enhanced, with a more pronounced effect on smaller scales. This enhancement leads to the separation of the unburned pockets from the main flame. Concurrently, both the flame length and the flame area decrease with the augmentation of φ and HPR, indicating a more concentrated combustion process and increased combustion intensity under hydrogen-enriched and pure hydrogen conditions. The study also observed a slight increase in both the negative and positive curvatures of the flame front, with a more notable increase in the negative curvature. The increased negative curvature results in an elevated degree of wrinkling and a higher value of Σ (flame surface density), reaching a maximum of 0.876 mm−1 under the conditions where φ is 0.8 and ⟨c⟩ (mean progress variable) is 0.5, resulting in the smallest observed flame volume of 100.6 mm3. Upon coupling the flame with the flow field, it was discovered that the exit flow field of the array micro-tube exhibits symmetry and a characteristic conical flame shape. The burning velocity of the side flame brushes increases, and the velocity peak shifts upstream. The aforementioned findings confirm that the addition of hydrogen increases the laminar flame velocity, enabling the flame to stably anchor to the microtube outlet and thereby enhance the flame's robustness and stability.
Delayed fragmentation of weakly bound Kr2+
Authors: Ma Junyang , Wang Pengzhao , Li Shuqi , Xiong Lei , Hu Zhubin , Sun Haitao , Yang Yan , Sun Zhenrong
Published: October 2024

We report the experimental observation of the delayed fragmentation of the weakly bound dimer Kr2+ produced through the single ionization of Kr2 by a femtosecond laser field. The observed time delay between ionization and fragmentation, which reflects the survival time of the resulting Kr2+, is measured on the microsecond timescale. A detailed analysis of the kinetic energy releases of the ejected fragments and photoelectrons suggests that this delayed fragmentation arises from the radiative decay of the long-lived Kr2+, transitioning from the bound state II(1/2u) to the repulsive state I(1/2g).
Caudal peduncle-inspired two-degree-of-freedom elastic coupling fin propulsion method
Authors: Lu Yiming , Zhang Haicheng , Liu Jiarui , Ding Jun , Xu Daolin
Published: October 2024

Marine animals orchestrate the swimming process through the coordinated interplay of body musculature, the caudal peduncle, and the caudal fin. However, understanding the coordinated action of these components to achieve high propulsive performance remains a significant challenge. The study proposes a self-propulsive physical model with two-degree-of-freedom (DoF) elastic coupling inspired by the caudal peduncle, where the caudal peduncle exhibits spring-like behaviors influencing the tail's motion along heave/pitch directions. The complex nonlinear fluid–structure interaction issues are addressed via the nonlinear vortex sheet method. The study primarily compares the propulsive performance of the two-DoF elastic coupling caudal fin model with the pitch caudal fin model. Numerical results show that the peak efficiency of the proposed model is nearly eight times that of the pitch caudal fin model. Additionally, the study reveals that the high-propulsive mechanism lies in generating the figure of a butterfly phase diagram for the hydrodynamic forces and exploiting vortices to decrease energy consumption. These findings offer novel perspectives for the future design of high-efficiency underwater robots.
Instability mechanism and vibration performance of a pumped storage power station under runaway conditions
Authors: Liu Yi , Yu Xiao-dong , Qiu Wei-xin , Hu Chao , Zhang Jian
Published: October 2024

With the large-scale access of renewable energy to the grid, the load rejection of pumped storage power stations (PSPSs) has become increasingly frequent, thus increasing the possibility of runaway accidents. This study aimed to investigate the instability mechanism and vibration performance of a PSPS by considering the coupling effect of the pressurized pipe and pump-turbine under the runaway condition. First, models of the PSPS based on the elastic water-column (elastic model) and rigid water-column (rigid model) were established. Subsequently, the vibration performances of the elastic and rigid models were compared. The comparison revealed that the runaway instability characteristics of the PSPS were mainly manifested as a high-frequency and large-amplitude vibration caused by the elastic water-column, which was not observed in the rigid model. Therefore, the elasticity of the water-column, which has normally been neglected or simplified using a rigid water-column in previous studies, has a significant effect on the runaway stability. Finally, the effects of other factors on the stability and vibration performance were clarified. The runaway stability was mainly determined by the characteristics of the runaway operating point. The discharge-head relationship coefficient (S5) for quantifying the stability performance of the runaway operating point was extracted. Moreover, increasing pipe friction loss could suppress runaway instability. Additionally, the pipe water inertia only affected the runaway vibration performance but not the runaway stability result. Overall, the study findings deepen the understanding of the physical nature of runaway instability and provide guidance for pump-turbine runner design and stable operation of PSPSs.
(Benzene-1,2,4,5-tetrayl)tetrakis(3-(1-carboxylatomethylpyridinium)), a novel uranyl-complexing tetrazwitterion
Authors: Lee Young Hoon , Kusumoto Sotaro , Atoini Youssef , Hayami Shinya , Kim Yang , Harrowfield Jack , Thuéry Pierre
Published: October 2024

The tetrazwitterionic, tetracarboxylate (benzene-1,2,4,5-tetrayl)tetrakis(3-(1-carboxylatomethylpyridinium)) (L) has been synthesized and used as a ligand in mixed-ligand complexes of the uranyl cation involving anionic carboxylates. {[(UO2)2(tdc)2(L)]·2H2O}n (1), where tdc2– is 2,5-thiophenedicarboxylate, crystallizes as a monoperiodic, ladder-like coordination polymer in which two UO2(tdc) rows are bridged by L ligands with monodentate carboxylate groups. {[(UO2)2(OH)4(L)]·2H2O}n (2) is a diperiodic polymer in which the dinuclear (UO2)2(OH)22+ units are the nodes of a square lattice (sql) network and L being bound by its four monodentate carboxylate groups. The positional isomer (benzene-1,2,4,5-tetrayl)tetrakis(4-(1-carboxylatomethylpyridinium)) (L′) undergoes decarboxylation during synthesis under solvo-hydrothermal conditions, giving tetracationic (benzene-1,2,4,5-tetrayl)tetra{4-(N-methylpyridinium)} (btp4+) included as a counterion in [btp][(UO2)4(O)2(pht)4]·1.5H2O (3), where pht2– is phthalate. The discrete, tetranuclear complexes in 3 are of the usual form with two μ3-oxo bridges and rows of alternating anions and cations linked through π–π interactions arranged into layers.
Complement activation by IgG subclasses is governed by their ability to oligomerize upon antigen binding
Authors: Frischauf Nikolaus , Strasser Jürgen , Borg Ellen G.F. , Labrijn Aran F. , Beurskens Frank J. , Preiner Johannes
Published: October 2024

Complement activation through antibody–antigen complexes is crucial in various pathophysiological processes and utilized in immunotherapies to eliminate infectious agents, regulatory immune cells, or cancer cells. The tertiary structures of the four IgG antibody subclasses are largely comparable, with the most prominent difference being the hinge regions connecting the Fab and Fc domains, providing them with unique structural flexibility. Complement recruitment and activation depend strongly on IgG subclass, which is commonly rationalized by differences in hinge flexibility and the respective affinities for C1, the first component of the classical complement pathway. However, a unifying mechanism of how these different IgG subclass properties combine to modulate C1 activation has not yet been proposed. We here demonstrate that complement activation is determined by their varying ability to form IgG oligomers on antigenic surfaces large enough to multivalently bind and activate C1. We directly visualize the resulting IgG oligomer structures and characterize their distribution by means of high-speed atomic force microscopy, quantify their complement recruitment efficiency from quartz crystal microbalance experiments, and characterize their ability to activate complement on tumor cell lines as well as in vesicle-based complement lysis assays. We present a mechanistic model of the multivalent interactions that govern C1 binding to IgG oligomers and use it to extract kinetic rate constants from real-time interaction data from which we further calculate equilibrium dissociation constants. Together, we provide a comprehensive view on the parameters that govern complement activation by the different IgG subclasses, which may inform the design of future antibody therapies.
AMBRA1 controls the translation of immune-specific genes in T lymphocytes
Authors: Gottlieb Simone , Shang Wanjing , Ye Deji , Kubo Satoshi , Jiang Ping Du , Shafer Samantha , Xu Leilei , Zheng Lixin , Park Ann Y. , Song Jian , Chan Waipan , Zeng Zhiqin , He Tingyan , Schwarz Benjamin , Häupl Björn , Oellerich Thomas , Lenardo Michael J. , Yao Yikun
Published: October 2024

T cell receptor (TCR) engagement causes a global cellular response that entrains signaling pathways, cell cycle regulation, and cell death. The molecular regulation of mRNA translation in these processes is poorly understood. Using a whole-genome CRISPR screen for regulators of CD95 (FAS/APO-1)-mediated T cell death, we identified AMBRA1, a protein previously studied for its roles in autophagy, E3 ubiquitin ligase activity, and cyclin regulation. T cells lacking AMBRA1 resisted FAS-mediated cell death by down-regulating FAS expression at the translational level. We show that AMBRA1 is a vital regulator of ribosome protein biosynthesis and ribosome loading on select mRNAs, whereby it plays a key role in balancing TCR signaling with cell cycle regulation pathways. We also found that AMBRA1 itself is translationally controlled by TCR stimulation via the CD28–PI3K–mTORC1–EIF4F pathway. Together, these findings shed light on the molecular control of translation after T cell activation and implicate AMBRA1 as a translational regulator governing TCR signaling, cell cycle progression, and T cell death.
Insects decline with host plants but coextinctions may be limited
Authors: Bassi Marlon I. E. , Staude Ingmar R.
Published: October 2024

The loss of wild plant populations is often assumed to lead to coextinctions, particularly among specialized insects. Despite global declines in both terrestrial insects and plants, the relationship between these trends remains elusive. Here, we address this gap by analyzing the relationship between population trends of insects and their host plants in Germany, encompassing over 150,000 interactions among 3,429 plant and 2,239 insect species, including both pollinators (bees and hoverflies) and herbivores (butterflies, moths, and sawflies). Our findings reveal parallel population declines of insects and host plants across taxa, except for more generalist hoverflies. However, simulated extinctions of threatened host plants led to limited coextinctions in insects. Notably, 96% of insect species retained over 25% of their host plant diversity, and among those, 98% still retained at least one common species in their interaction portfolio. Even highly specialized insects may persist because they tend to specialize in nonthreatened plant species. While uncertainties remain regarding the interchangeability of host plants, our findings suggest that insect coextinctions are far from a 1:1 match with plant extinctions. Our findings suggest the declining abundance of many plant species can contribute to insect decline yet challenge the common assumption that the extinction of threatened plant species will necessarily trigger an imminent extinction wave of associated insects. Interaction networks seem to be more resilient.
Light induces a rapid increase in cAMP and activates PKA in rod outer segments of the frog retina
Authors: Chernyshkova Olga , Erofeeva Natalia , Meshalkina Darya , Balykina Anna , Gambaryan Stepan , Belyakov Michael , Firsov Michael
Published: October 2024

The phototransduction cascade enables the photoreceptor to detect light over a wide range of intensities without saturation. The main second messenger of the cascade is cGMP and the primary regulatory mechanism is calcium feedback. However, some experimental data suggest that cAMP may also play a role in regulating the phototransduction cascade, but this would require changes in cAMP on a time scale of seconds. Currently, there is a lack of data on the dynamics of changes in intracellular cAMP levels on this timescale. This is largely due to the specificity of the sensory modality of photoreceptors, which makes it practically impossible to use conventional experimental approaches based on fluorescence methods. In this study, we employed the method of rapid cryofixation of retinal samples after light stimulation and subsequent isolation of outer segment preparations. The study employed highly sensitive metabolomics approaches to measure levels of cAMP. Additionally, PKA activity was measured in the samples using a western blot. The results indicate that when exposed to near-saturating but still moderate light, cAMP levels increase transiently within the first second and then return to pre-stimulus levels. The increase in cAMP activates PKA, resulting in the phosphorylation of PKA-specific substrates in frog retinal outer segments.
Quantum gravity phenomenology and the blackbody radiation
Authors: Turcati R , Soares I , Duarte S B
Published: October 2024

We analyze the blackbody radiation problem in the presence of quantum gravity effects encoded in modified dispersion relations. The spectral radiance and the generalized Stefan–Boltzmann law are studied in this context. Furthermore, the regime of low temperatures is also contemplated, where features related to the blackbody thermal laws and the thermodynamic quantities such as energy, pressure, entropy, and specific heat are obtained. Possible implications in compact objects such as neutron stars are also discussed.
Sensemaking of wave–particle duality in a scientific outreach minicourse: a study based in self-regulation
Authors: Thomas Becker Matheus Henrique , Heidemann Leonardo Albuquerque , Lima Nathan Willig
Published: October 2024

On the Internet, Quantum Mechanics is an area of physics that is shrouded in misinterpretations. In this scenario, scientific outreach may serve as an instrument for disseminating scientific knowledge. Especially in this context, it is important that people’s learning encompasses more than the meanings of concepts and laws, involving aspects related to the ‘why’ and ‘for what purpose’ the knowledge was and is constructed. We consider these aspects as components of the sense, the connotative and subjective dimension of conceptual learning which encompasses a positioning of an individual towards a concept and its relevance in the physics framework. Motivated by this, in the present study, we investigated the senses ascribed to the concept of wave–particle duality (WPD) by 121 participants in a two-day (five-hour) science outreach minicourse in the double-slit experiment. Drawing on the ideas of Franco et al (2023, Cadernos de Pesquisa do Programa de Pós-graduação em Ensino de Física da UFRGS (Research Notebooks from the Postgraduate Program in Physics Teaching at UFRGS), Pimenta Cultural Editors S/A), we posit sensemaking as a type of cognitive effort to overcome a situation, viewed as a self-regulatory phenomenon wherein individuals self-observe, self-evaluate, and self-react to the situation to achieve a certain goal. In addition to identifying the senses attributed to the concept of WPD, we assessed the relationships between these senses and participants’ performance in a standardized test of this concept, as well as their educational background and field of study. Data were collected using questionnaires answered before and at the end of the course. The senses ascribed to the concept of WPD were investigated through similarity and cluster analysis based on responses to essay questions. The relationships among these senses, questionnaire performance, and educational background were evaluated using non-parametric statistical tests. We infer two senses attributed to wave–particle duality: (1) WPD is a basic and fundamental concept that impacts the way we comprehend the essence of nature, and (2) WPD is a very advanced concept restricted to the field of Quantum Mechanics. A statistically significant correlation (0.26 was identified between the senses attributed and participants’ performance on the standardized test, suggesting that the sense ascribed to a concept and performance in questions requiring its mobilization are overlapping elements but constitute two distinct dimensions of learning that need to be assessed simultaneously.
Ponderomotive potential effects on strong field two-photon double ionization in neon
Authors: Veerbhan Vidhi , Chatterjee Souvik
Published: October 2024

In the context of the recently reported experiment on photoionization in neon atom, we theoretically study the photoionization of neon atom at a comparatively intense laser field. The calculated photoelectron spectrum for a Gaussian laser pulse show an asymmetric double peak line shape at a pulse duration of 14.2 fs and peak intensity of 1 × 1015 W cm−2. A systematic study clearly indicates that the ponderomotive potential of the photoelectron released during photoionization of neon is instrumental in causing the visible asymmetry. Interestingly, for similar laser parameters asymmetry in the photoelectron spectrum gets significantly reduced for a Sech2 shaped laser pulse. Time resolved photoelectron spectrum reveals that even for a Sech2 shaped laser pulse the two peak photoelectron spectrum is initially asymmetric and evolves into a symmetric line shape with increase in time. The results clearly indicate that irrespective of laser pulse shape asymmetry shows a non-linear decrease as a function of time. Our study also shows the possibility of controlling the asymmetry by varying the pulse duration. The calculations establishes a correlation between the effects of direct double ionization and ponderomotive potential on the asymmetry of the photoelectron spectrum at different pulse durations.
Evaluating the effects of three anesthetic regimens on retinal structure and function in the living mouse eye using a customized bimodal OCT/ORG system
Authors: Ma Yanhong , Dong Rongyao , Song Tianqi , Zhou Mingliang , Bai Jing , Wang Shuai , Bell Brent A , Zhang Pengfei
Published: October 2024

Optical coherence tomography (OCT) is a non-invasive imaging technique that generates cross-sectional images of biological tissues at millimeter-level penetration depth with micron-level resolution. In this study, we developed a custom spectral-domain OCT system equipped with a flash stimulus module for dual-modality imaging of mouse retinal structure and function. The axial resolution of the system reached ∼2.7/2 μm in air/tissue following optimization and calibration. We deployed this system to conduct in vivo OCT structural imaging and optoretinography (ORG) functional assessment of mouse retina to investigate the effects of three anesthesia regimens. Statistical analysis of the results indicates that anesthesia results in a smaller relative intensity of inner/outer segment junction and external limiting membrane and a thickening of the outer segment compared to an awake state. Meanwhile, significant differences were observed in the effects on retinal structure and function between isoflurane and tribromoethanol anesthesia, while differences between isoflurane and esketamine+xylazine groups were small. These findings suggest that the type of anesthetic should be taken into account when comparing imaging results across studies reported in the literature.
A novel ultra-wideband rasorber based on triple lossy layers
Authors: Wen Kaihuai , Wang Yun , Yue Xiuli , Qiu Riquan , Han Tiancheng
Published: October 2024

By surpassing the limitations of transmission efficiency found in traditional double-lossy-layers rasorbers, a novel rasorber with three distinct lossy absorption layers is presented, offering low insertion loss and ultra-wideband bandwidth. Compared to conventional rasorbers which have non-negligible insertion loss and large thickness, our design extends the bandwidth in the higher frequency band without increasing thickness, while maintaining high transmission efficiency. To further broaden the absorption band, an additional lossy layer resonating at lower frequency band, with high transmission above the resonance frequency was incorporated into the previous design. The composite structure is developed by the equivalent circuit model whose results are in accord well with the simulation results. The simulated results demonstrate that an insertion loss of 0.37 dB at 10 GHz, and a 159.5% 10 dB reflection reduction bandwidth from 2.04 to 18.05 GHz are attained under normal incidence. A manufactured specimen of the proposed structure is measured to validate our design.
Discharge modes evolution characteristics of metal particle on the spacer surface in AC gas insulated switchgear
Authors: Nie Jiayi , Fan Xing , Pei Zhehao , Ge Dong , Xu Yuan , Xiang Nianwen , Chen Weijiang
Published: October 2024

Flashover faults on gas insulated switchgear (GIS) insulators induced by metal particles occur frequently. Previous studies have obtained the characteristics of partial discharges (PDs) induced by metal particles on spacer surfaces, but these characteristics cannot explain the detection failure of ultra-high frequency (UHF) online monitoring. To enable further study of the PD characteristics induced by surface metal particles, the space electric field and a very-high-sensitivity pulse current (PC) measurement system were established. The electric field and PC characteristics of a PD induced by metal particle on the spacer surface of a 126 kV GIS were obtained. Two PD modes were found to be induced by surface metal particles. In addition to the typical pulse discharge (TP), there is a micro-discharge group (MG) mode with low apparent charge and long duration. The average apparent charge of the MG mode is approximately one-tenth of that of the TP at 0.4 pC. Its duration may extend to the millisecond level, causing significant distortion of the spatial electric field while hardly producing UHF signals. Moreover, increasing the applied voltage will increase the proportion of the MG within the total discharge, where this proportion can reach more than 90% before flashover, and the proportion of the discharge pulses that generates UHF signals is as low as 1%. The MG generation mechanism is analysed, the ion group stranded on the spacer surface by the TP changes the local electric field at the tip of the metal particle, which reduces the development length and apparent charge of the MG. Low apparent charge is cleared easily by the background electric field and thus the discharge interval is very short. This paper can provide an important basis for revealing the mechanism of GIS spacer surface discharge induced by metal particles and solving the effectiveness of PD monitoring devices.
Three-dimensional turning force sensor based on a decagonal ring structure: crosstalk mitigation design and performance optimization
Authors: Wang Peng , Han Jike , Qiangdai Yu , Zhang Changming , Hu Shanzhou , Yang Fan , Yan Zhipeng , Shen Bo , Zhang Xian , Wang kun
Published: October 2024

Real-time data acquisition using high-precision three-dimensional turning force sensors is crucial for intelligent manufacturing. However, existing sensors face challenges such as low integration levels and poor crosstalk resistance, rendering them inadequate for high-precision measurements. Theoretical analysis has demonstrated that a fully centered decagonal ring structure can effectively mitigate the effects of eccentric loading. This study focuses on designing a fully centered turning force sensor with minimal crosstalk. To achieve a balance between sensitivity and stiffness, multi-objective optimization was conducted using GWO-BP and TOP algorithms, resulting in a twofold increase in the sensitivity of the decagonal ring. The sensor design incorporates metallic strain gauges, instrumentation amplifiers, and peripheral circuits into the ring arms of the decagonal structure. Experimental results show that the sensor’s amplified sensitivities in the Fc, Ff, and Fp directions are 11.78 mV N−1, 10.31 mV N−1, and 1.78 mV N−1, respectively. The first three natural frequencies in an unconstrained state are 2518.5 Hz, 2537.5 Hz, and 4256.4 Hz. The sensor’s Fc-Fy crosstalk ranges from 0.18% to 0.88%, with noise limits for the Fc, Ff, and Fp directions of 0.035 N, 0.03 N, and 0.23 N, respectively. Cutting experiments have demonstrated that under varying spindle speeds and cutting depths, the sensor effectively detects surges in cutting force caused by rapid tool retraction, as well as other common faults.
Road boundary extraction method from mobile laser scanning point clouds
Authors: Xin Gongfeng , Cong Bori , Liu Rufei , Zhang Zhenhu , Liu Mengya
Published: October 2024

With the rapid development of mobile laser scanning (MLS) technology, high-precision three-dimensional (3D) point cloud data has shown great potential in different fields such as topographic mapping, road asset management and smart city construction. 3D point cloud data contains not only position information, but also the shape and attributes of the target, which is very convenient for obtaining road information. Accurate extraction of the road boundary is a basic task for obtaining road infrastructural data, which can support the generation of high-precision maps, vehicle navigation and autonomous driving. However, road boundary extraction in urban environments is easily occluded such as vehicles and pedestrians on the road, which leads to problems such as difficulty and incomplete extraction of MLS point cloud road boundaries. To address this problem, this study proposes a road boundary extraction method that integrates pavement edge information, accurately considers the position of the road boundary from two dimensions, eliminates false boundaries, and completes the missing boundary through the extracted boundary spatial relationship. First, grid elevation filtering is used to remove high-level non-ground points. Then the pavement edges and curb stone points are extracted from the preprocessed point cloud, and they are superimposed to remove false boundary points to obtain accurate road boundaries. Finally, based on the spatial relationship of road boundaries, missing parts are detected and repaired to obtain complete road boundaries. Experimental results show that the accuracy on real road scenes exceeds 98%, the completeness rate is above 91%, and the extraction quality is above 90%, which verifies the effectiveness and accuracy of this method.
Computational design of 4D printed shape morphing lattices undergoing large deformation
Authors: Walker Andreas , Shea Kristina
Published: October 2024

In 4D Printing, active materials are embedded in structures such that the application of an external stimulus, usually coming from the environment, results in a structural response. To design structures that achieve a targeted shape change for a defined stimulus, also known as shape morphing, the material distribution and structure needs to be tuned. However, the computational design of such material distributions and structures is a challenging task and remains, despite recent advances, unable to fully leverage the entire design freedom offered by state-of-the-art 4D printing technology. Notable gaps concern the handling of large and complex deformations, the high computational cost, and the exploration of the design space by the generation of alternative solutions. In this article, a method is presented to fill this gap. First, an artificial neural net is trained that represents a deformation map that occurs during actuation. Then, a shape morphing truss is designed that achieves this deformation during actuation. The method is used to solve four shape morphing problems, where superior capabilities are demonstrated in terms of magnitude and complexity of deformations that can be handled, efficient generation of alternative solutions and versatility. Due to these capabilities, the method enables exploration of the full potential of 4D printing technology to create stimuli-responsive, multifunctional structures.
Improved gas sensing properties of copper-doped MoSe2 monolayers: a first-principles study on CO2 and NO2 adsorption
Authors: Jaiswal S N , Pandey Bramha P , Kumar Dharmendra , Mishra Neha , Tomar V K , Kumar Santosh
Published: October 2024

This paper investigates the impact of copper (Cu)-doped MoSe2 monolayer (ML) on gas sensing properties. The adsorption behaviour of CO2 and NO2 gas molecules on Cu-doped MoSe2 ML is reported and various sensing and electronic parameters such as adsorption energy, charge transfer and recovery time, are computed to delineate the adsorption characteristics and gas sensitivity. In our study, the doped Cu-atom in Se vacant MoSe2 ML shows the adsorption energies to be −1.32 eV (O-orient) and −1.72 eV (C-orient), for CO2, while for NO2, they are −0.879 eV (O-orient) and −1.06 eV (N-orient), respectively. The negative formation energy of −6.62 eV shows the electronic stability of Cu-doped MoSe2 ML and thermal stability, demonstrated by the molecular dynamics study through the Nose-Vervlet Thermostat (NVT) algorithm. Also, significant changes are observed in electronic conductivity and work function upon adsorbed Cu-MoSe2 ML. Lastly, these outcomes illustrate that Cu doping amplifies the capture ability of MoSe2 ML towards gas molecules, fostering improved electron interaction between the substrate surface and gas molecules, consequently enhancing its gas sensing ability.
Photon-modulated displaced thermal states: negativity and non-Gaussianity
Authors: Wu Wei-feng , Fang Yong , Fu Peng
Published: October 2024

In this paper, we propose a new non-Gaussian quantum state, termed the photon-modulated displaced thermal state (DTS). Using the operator ordering method, we obtain the normal ordering product of its density operator and then investigate its normalization, the negativity of its Wigner function and its non-Gaussianity.
Tunable mid-infrared absorber based on Dirac metamaterials
Authors: Li Bo , Cheng Guolun , Sun Bo , Yu Yingying , Yang Wenxing
Published: October 2024

In this paper, a tunable metamaterial absorber based on a Dirac semimetal is proposed. It consists of three different structures, from top to bottom, namely a double semicircular Dirac semimetal resonator, a silicon dioxide substrate and a continuous vanadium dioxide (VO2) reflector layer. When the Fermi energy level of the Dirac semimetal is

10

meV
,

the absorber absorbs more than 90% in the 39.06–84.76 THz range. Firstly, taking advantage of the tunability of the conductivity of the Dirac semimetal, dynamic tuning of the absorption frequency can be achieved by changing the Fermi energy level of the Dirac semimetal without the need to optimise the geometry and remanufacture the structure. Secondly, the structure has been improved by the addition of the phase change material VO2, resulting in a much higher absorption performance of the absorber. Since VO2 is a temperature-sensitive metal oxide with an insulating phase below the phase transition temperature (about 68 °C) and a metallic phase above the phase transition temperature, this paper also analyses the effect of VO2 on the absorptive performance at different temperatures, with the aim of further improving absorber performance.