bluuebunny/crossref_metadata_2025 huggingface dataset:
Understanding dynamics in coarse-grained models. III. Roles of rotational motion and translation-rotation coupling in coarse-grained dynamics
Authors: Jin Jaehyeok , Lee Eok Kyun , Voth Gregory A.
Published: October 2023

This paper series aims to establish a complete correspondence between fine-grained (FG) and coarse-grained (CG) dynamics by way of excess entropy scaling (introduced in Paper I). While Paper II successfully captured translational motions in CG systems using a hard sphere mapping, the absence of rotational motions in single-site CG models introduces differences between FG and CG dynamics. In this third paper, our objective is to faithfully recover atomistic diffusion coefficients from CG dynamics by incorporating rotational dynamics. By extracting FG rotational diffusion, we unravel, for the first time reported to our knowledge, a universality in excess entropy scaling between the rotational and translational diffusion. Once the missing rotational dynamics are integrated into the CG translational dynamics, an effective translation-rotation coupling becomes essential. We propose two different approaches for estimating this coupling parameter: the rough hard sphere theory with acentric factor (temperature-independent) or the rough Lennard-Jones model with CG attractions (temperature-dependent). Altogether, we demonstrate that FG diffusion coefficients can be recovered from CG diffusion coefficients by (1) incorporating “entropy-free” rotational diffusion with translation-rotation coupling and (2) recapturing the missing entropy. Our findings shed light on the fundamental relationship between FG and CG dynamics in molecular fluids.
Richtmyer–Meshkov instability of a single-mode heavy–light interface in cylindrical geometry
Authors: Li Jiaxuan , Wang He , Zhai Zhigang , Luo Xisheng
Published: October 2023

Richtmyer–Meshkov (RM) instability of a single-mode SF6–air interface subjected to a convergent shock is investigated experimentally. The convergent shock tube is specially designed with an opening tail to weaken the Rayleigh–Taylor effect and eliminate the reflected waves' effect. The gas layer scheme is used to create a heavy gas environment at the upstream side of the interface. Before phase inversion is finished, the amplitude reduction is accelerated, but the Bell–Plesset (BP) effect in this process is found to be negligible. After phase inversion is completed, the linear growth rate is generally predicted due to small amplitude and the weak BP effect. In nonlinear regime, an existing nonlinear model is revised based on the Padé approximation to give a better prediction of amplitude growth. The spike amplitude grows almost linearly, whereas the bubble amplitude gradually saturates and even reduces. For a heavy-light interface in convergent geometry, although both the spike and bubble amplitude growths are promoted by the BP effect, the spike growth is more promoted than the bubble. The BP effect enhances generation of the second-order harmonic, which results in saturation and reduction of the bubble amplitude. The discrepancy in the BP effect between light-heavy and heavy-light interfaces is qualitatively demonstrated for the first time.
Ultrafast dynamics of CN radical reactions with chloroform solvent under vibrational strong coupling
Authors: Fidler Ashley P. , Chen Liying , McKillop Alexander M. , Weichman Marissa L.
Published: October 2023

Polariton chemistry may provide a new means to control molecular reactivity, permitting remote, reversible modification of reaction energetics, kinetics, and product yields. A considerable body of experimental and theoretical work has already demonstrated that strong coupling between a molecular vibrational mode and the confined electromagnetic field of an optical cavity can alter chemical reactivity without external illumination. However, the mechanisms underlying cavity-altered chemistry remain unclear in large part because the experimental systems examined previously are too complex for detailed analysis of their reaction dynamics. Here, we experimentally investigate photolysis-induced reactions of cyanide radicals with strongly-coupled chloroform (CHCl3) solvent molecules and examine the intracavity rates of photofragment recombination, solvent complexation, and hydrogen abstraction. We use a microfluidic optical cavity fitted with dichroic mirrors to facilitate vibrational strong coupling (VSC) of the C–H stretching mode of CHCl3 while simultaneously permitting optical access at visible wavelengths. Ultrafast transient absorption experiments performed with cavities tuned on- and off-resonance reveal that VSC of the CHCl3 C–H stretching transition does not significantly modify any measured rate constants, including those associated with the hydrogen abstraction reaction. This work represents, to the best of our knowledge, the first experimental study of an elementary bimolecular reaction under VSC. We discuss how the conspicuous absence of cavity-altered effects in this system may provide insights into the mechanisms of modified ground state reactivity under VSC and help bridge the divide between experimental results and theoretical predictions in vibrational polariton chemistry.
Thermal characterization of carbon-rich boron carbonitride foams for thermal management applications
Authors: Ben-Shimon Yahav , Pradhan Anway , Glam Binyamin , Levin Natali , Ya'akobovitz Assaf
Published: October 2023

The increasing need to evacuate heat from electronic components encourages the use of new thermal materials. Motivated by the good heat convection of graphene foam (GF), we have integrated boron and nitrogen atoms into GF, thereby obtaining carbon-rich boron carbonitride (BCN) foam, which shows a significant improvement to its thermal characteristics. We used the infrared micro-thermography method and showed that carbon-rich BCN foam has an exceptionally large effective convection area and a high convection coefficient, which is comparable to that obtained under forced convection. Additionally, carbon-rich BCN foam presents remarkable thermal stability with a degradation temperature of ∼750 °C. Finally, we attached the carbon-rich BCN to an electric circuit and demonstrated its feasibility to evacuate heat from electronic components. Therefore, we pave the path for the integration of carbon-rich BCN foams in advanced thermal applications, such as thermal management reinforcement in composites and heat dissipation elements.
Role of losses and coupling in bright-dark metasurfaces mimicking non-Hermitian parity-time symmetric systems
Authors: K. N. Indu Krishna , Punjal Ajinkya , Pandey Utkarsh , Puranik Ruturaj , Prabhu Shriganesh , K. N. Deepthi , Roy Chowdhury Dibakar
Published: October 2023

All real systems are essentially non-conservative in nature, which is non-Hermitian in the fundamental premises of the quantum realm. Such open systems obeying parity-time (PT) symmetry can offer intriguing physics, which has sparked much attention in recent years. The thoughtful interplay of loss and gain in PT-symmetric systems can tune the eigenstates from real to complex space passing through a singular point known as an exceptional point (EP) with concurrently coalescing the discrete eigenstates. In this regard, artificially engineered near-field coupled metasurfaces provide a remarkable podium to introduce as well as control loss and coupling strength simultaneously, manifesting a practical channel to attain EP. Motivated by this notion, we have theoretically explored near-field coupled dark-bright-mode assisted terahertz metasurfaces imitating a typical non-Hermitian PT-symmetric system. Structurally, such metasurfaces are realized by utilizing a pair of orthogonally twisted near-field coupled split-ring resonators (bright-dark-resonators). We have meticulously examined such a system with two distinctive approaches, i.e., the loss parameter and inter-resonator coupling strength. Eventually, our exploration demonstrates that judicious modulation of the loss parameter can invoke an undemanding route to approach the other wisely elusive exceptional point. We believe that this comprehensive study of non-Hermitian quantum systems in a photonic context can lead to the development of accurate and precise ultra-sensitive sensors besides other futuristic photonic devices.
Anisotropic dynamics of an interfacial enzyme active site observed using tethered substrate analogs and ultrafast 2D IR spectroscopy
Authors: Hill Tayler D. , Basnet Sunil , Lepird Hannah H. , Rightnowar Blaze W. , Moran Sean D.
Published: October 2023

Enzymes accelerate the rates of biomolecular reactions by many orders of magnitude compared to bulk solution, and it is widely understood that this catalytic effect arises from a combination of polar pre-organization and electrostatic transition state stabilization. A number of recent reports have also implicated ultrafast (femtosecond-picosecond) timescale motions in enzymatic activity. However, complications arising from spatially-distributed disorder, the occurrence of multiple substrate binding modes, and the influence of hydration dynamics on solvent-exposed active sites still confound many experimental studies. Here we use ultrafast two-dimensional infrared (2D IR) spectroscopy and covalently-tethered substrate analogs to examine dynamical properties of the promiscuous Pyrococcus horikoshii ene-reductase (PhENR) active site in two binding configurations mimicking proposed “inactive” and “reactive” Michaelis complexes. Spectral diffusion measurements of aryl-nitrile substrate analogs reveal an end-to-end tradeoff between fast (sub-ps) and slow (>5 ps) motions. Fermi resonant aryl-azide analogs that sense interactions of coupled oscillators are described. Lineshape and quantum beat analyses of these probes reveal characteristics that correlate with aryl-nitrile frequency fluctuation correlation functions parameters, demonstrating that this anisotropy is an intrinsic property of the water-exposed active site, where countervailing gradients of fast dynamics and disorder in the reactant ground state are maintained near the hydration interface. Our results suggest several plausible factors leading to state-selective rate enhancement and promiscuity in PhENR. This study also highlights a strategy to detect perturbations to vibrational modes outside the transparent window of the mid-IR spectrum, which may be extended to other macromolecular systems.
327 Gbps THz silicon photonic interconnect with sub-λ bends
Authors: Gupta Manoj , Navaratna Nikhil , Szriftgiser Pascal , Ducournau Guillaume , Singh Ranjan
Published: October 2023

Miniaturized photonic devices at the terahertz (THz) band are envisioned to bring significant enhancement to data transfer capacity and integration density for computing and future wireless communications. Broadband silicon waveguiding technology has continuously matured to advance low-loss platforms for integrated solutions. However, challenges are faced in realizing compact waveguiding platforms with different degrees of bends due to bend induced losses and mode distortion. Here, we demonstrate multiple bend incorporated photonic crystal waveguide platforms for multicarrier on-chip transmission. Our silicon interconnect device exhibits optimized bending radius to the free space wavelength ratio of 0.74, without signal distortion and transmission bandwidth of 90 GHz, representing 25.4% fractional bandwidth at 355 GHz. The broadband waveguide interconnect enables an aggregate data transfer rate of 327 Gbps by sending the complex modulated data over multiple carriers. This work augments the development of THz photonic integrated circuit for the future generations of on-chip high data rate interconnect and wireless communication, ranging from the sixth to X generation (6G to XG).
Features and mechanisms of asymmetric wake evolution downstream of two parallel circular cylinders
Authors: Yan Yuhao , Chen Weilin , Zhang Zhimeng , Ji Chunning , Srinil Narakorn
Published: October 2023

Uniform flow past side-by-side circular cylinders is a classical fluid dynamic model that triggers rich phenomena, from which asymmetric wakes usually emerge. Such asymmetry arising from a completely symmetric geometric setting is of theoretical interest when exploring the system bifurcations. Using direct numerical simulation, a detailed parametric map of the wakes behind two side-by-side circular cylinders is presented with several asymmetric wake patterns. These include asymmetric anti-phase (AAP), typical and special deflected (DF), and in-phase (IP) flows, for which AAP and special DF flows are discovered for the first time. Additionally, the IP flow is simulated by both two- and three-dimensional grids to explore the effect brought by three-dimensional vortical structures. The evolution of these asymmetric wakes is analyzed in different phases, with the aid of the wavelet transform, Hilbert–Huang transform, and dynamic mode decomposition, to reveal their temporal variations of developing features. Interestingly, although revealing with distinct fully developed flow fields, there are several common dynamics identified among these wake patterns: AP and IP vortex shedding, wake transition, and gap flow oscillation. The vicissitudes of dynamic flow evolution allow us to further differentiate several wake patterns and ultimately contribute to a deeper understanding of asymmetric flows.
Predicting the energy stability limit of shear flows using weighted velocity components
Authors: Nagy Péter Tamás , Kulcsár Márton
Published: October 2023

Predicting the subcritical transition in fluid dynamic systems remains a challenging task, but recent advancements utilizing edge tracking methods, polynomial Lyapunov functions, and various energy norms have shown promise. In this study, we propose a novel approach by defining the general kinetic energy through weighted velocity components. The minimal Reynolds number is determined, where the derivative of this generalized energy with respect to time is zero. The procedure is similar to that of the well-known Reynolds–Orr equation. Unlike traditional methods, our approach does not necessitate the monotonic decay of the classic perturbation kinetic energy, resulting in a larger critical Reynolds number and reduced conservativeness of the Reynolds–Orr equation. However, the energy production of the pressure is not negligible, in contrast to the classical Reynolds–Orr equation. The pressure's implicit dependence on the velocity field complicates the variation process. To address this, a method is presented to handle the problem effectively. Our approach is then applied to analyze parallel flows, specifically the plane Couette and plane Poiseuille flows, wherein the problem can be further simplified using the complex Fourier transformation. The weights of velocity components are optimized to maximize the critical Reynolds number, resulting in a significant increase.
Investigating unsteady airflow characteristics in the human upper airway based on the clinical inspiration data
Authors: Jing Hao , Ge Haiwen , Wang Li , Choi Sanghun , Farnoud Ali , An Zhongnan , Lai Wending , Cui Xinguang
Published: October 2023

To enhance understanding of the airflow characteristics in the human respiratory system during realistic inspiration, we investigated the airflow field in a human upper airway model using large eddy simulation and the dynamic grid method, taking into account clinically measured inspiratory characteristics. The results reveal the following novel findings: (1) The laryngeal jet and recirculation zone exhibit significant unsteadiness, with their dynamic characteristics primarily influenced by the transient inspiration flow rate and glottis motion. This pattern holds true for other airflow characteristics as well. (2) Glottis expansion reduces the energy consumed during inhalation for both steady and unsteady inspiratory flow rates, with the degree of expansion being directly related to the reduction in energy. We can accurately predict power loss by considering the glottis area and inspiratory flow rate. (3) Analysis of spectral entropy clearly demonstrates that the flow transitions from the laminar to turbulence earlier when using clinical inspiration data. Turbulence intensity in the trachea increases when either glottis motion or the transient inspiratory is ignored. In conclusion, the airflow dynamics are significantly more unsteady compared to cases where we ignore either glottis motion or the transient inspiratory flow rate. A precise understanding of realistic respiratory airflow cannot be achieved by assuming either a rigid glottis or a steady inspiration pattern. Therefore, it is crucial to use accurate inspiratory data when studying the properties of airflow structures in the human respiratory system. Moreover, incorporating more physiological data is also essential to obtain realistic respiratory airflow characteristics.
Experimental study of holographic metasurface for beam steering applications
Authors: Babu Raja , Agrahari Rajan , Mevada Pratik , Jain Pradip Kumar , Mahto Manpuran
Published: October 2023

In this article, a compact and high-gain, wide steering range and very low cross-polarization level holographic metasurface for beam steering is presented. The triangular modulated impedance surface is used for radiating the desired wave. The direction of the radiated beam is controlled through the varactor diode by changing the surface impedance of the device. The two prototypes of the designed device have been fabricated with two different varactor diodes. A higher gain of 11.7 dBi with a lower beam steering range of 25° and a radiation efficiency above 70% has been obtained from the device with a varactor diode SMV1405-079LF having lower parasitic resistance and larger capacitance properties. However, another fabricated device with higher parasitic resistance and lower capacitance property varactor diode SMV2201-40LF gives a lower gain of 9.1 dBi, a radiation efficiency below 55%, and a larger beam steering range of 61°. The experimental results are in good agreement with the simulation ones. The proposed device can be used for various applications like autonomous vehicles, toll plazas, and satellite communication.
Intelligent perception of tandem flapping wings' flow field environment with sparse detectors
Authors: Ji Tingwei , Jin Fan , Zheng Hongyu , Zhang Xinshuai , Xie Fangfang , Zheng Yao
Published: October 2023

Bionic flapping wing vehicles have great potential for civil and defense applications due to their flexibility and concealment at low Reynolds numbers. Since traditional flow field pattern recognition methods are difficult to identify effective information from the measured local flow field and deduce the state information of the moving body, this study uses an artificial intelligence method to establish the internal correlation between flow field pattern and state information. Specifically, a fully connected neural network is adopted to recognize the tandem flapping wings' flow field pattern by using different data acquisition methods and detector array distribution methods. Compared with the neural network based on time series data, the neural network based on spatial distribution data can realize the real-time judgment of flow field environment, which is closer to the real-time requirements in practical applications. In the paper, the intelligent perception of multi-flapping wings' flow field environment with sparse detectors is carried out and lays the theoretical foundation for autonomous navigation and obstacle avoidance of flapping wing aircrafts.
Intrinsic viscosity and dielectric relaxation of ring polymers in dilute solutions
Authors: Kumar Sumit , Biswas Parbati
Published: October 2023

The absence of chain ends makes ring polymers distinctly different from their linear analogues. The intrinsic viscosity, complex viscosity and the dielectric relaxation of ring polymers are investigated within the tenets of the optimized Rouse–Zimm theory. The distance dependent excluded volume interactions (EVIs) are obtained from Flory’s mean field theory. The hydrodynamic interactions (HIs) between the pairs of monomers are estimated using the preaveraged Oseen tensor. The intrinsic viscosity of linear and ring polymers both with and without EVI are compared as a function of ring size. A monotonically increasing trend of the intrinsic viscosity is observed in both cases. The intrinsic viscosity of both linear and ring polymers both with and without EVI show a very good agreement with the experimental results of polystyrene over a wide range of molecular weights in both good and theta solvents, respectively. The fractal dimensions of the ring polymers with EVI lie between that of a random walk and a self-avoiding walk model of linear polymers in three dimensions. The ring size increases with EVI and the effect of EVI is stronger on larger rings than that on smaller rings. The dielectric relaxation follow a connectivity independent universal scaling behavior at low and high frequency regions. The imaginary part of the complex dielectric susceptibility displays a local maxima in the intermediate frequency region, which reveals a structure dependent behavior of the rings. The theoretically calculated dielectric loss of ring polymers with HI matches well with those obtained from experiments.
Excitation and modulation of exchange spin waves in CoFeB films
Authors: Jin Ying , Zhao Yibing , Liang Bokai , Jiang Changjun
Published: October 2023

Spin waves in nanostructures have great potential to be future spintronic information carriers. Here, we report the excitation and modulation of exchange spin waves in Co20Fe60B20 (CoFeB) films by varying magnetic anisotropy. In a 50 nm-thick CoFeB film, the effective excitation of perpendicular standing spin waves (PSSWs) is achieved due to the uniaxial anisotropy induced by oblique sputtering. Additionally, patterning the films into a periodic array of rectangles enables the excitation of both exchange-dominated surface spin waves and PSSWs, with the modulation of spin waves achievable by altering the length–width ratio of the rectangle. It is worth noting that PSSWs are present in the easy axis, whereas surface spin waves are observed in the hard axis, emphasizing the significant influence of shape anisotropy on spin waves. Furthermore, we demonstrate the existence of PSSW in a CoFeB/Pb(Mg1/3Nb2/3)O3-Pb0.7Ti0.3O3 (PMN-PT) multiferroic heterostructure. The resonance field of PSSW can be shifted by applying electric fields, which originates from the strain anisotropy driven by the piezoelectric effect. These findings are expected to provide valuable insights for the development of energy-efficient spintronic devices and high-frequency data processing systems.
A new modeling method to evaluate effective forced-convective heat transfer rate of pipe flow with endothermic chemical reactions
Authors: Xu Shuai , Feng Yu , Zhang Yifeng , Qin Jiang , Li Bing
Published: October 2023

Heat transfer correlation describes the relationship between heat transfer and factors such as fluid properties and flow conditions. The establishment of heat transfer correlations is of paramount importance in the design and calculation of heat exchangers and reactors in various chemical engineering fields as well as in certain aerospace applications. In this study, we present a theoretical derivation of a heat transfer correlation model for fully developed flow with gas-phase homogeneous chemical reactions. By means of theoretical derivations, the modeling of complex multi-physics coupling problems can be significantly simplified, and the impact of chemical reactions can be effectively demonstrated. The concept of effective specific heat and effective thermal conductivity are generalized to finite-rate chemically reacting flow. Modifications are proposed for Nusselt number correlation. It is shown by preliminary verification that evaluating error of new correlation has been significantly decreased by the modification. The enhancement factor can be evaluated by specific ratio cpr,x/cp*. To demonstrate the reliability of the derived correlation, we carry out numerical simulations and compare the results with derived formulations. The simulations show good agreement with the theoretical values, demonstrating that the derived correlation is both theoretically grounded and practically usable.
Numerical investigation of droplet impact dynamics on Janus-textured heated substrates
Authors: Huang Jiangxu , Wang Lei , Hu Junjie
Published: October 2023

Janus-textured substrates refer to surfaces with heterogeneous topographies, which have received particular attention recently due to their potential application in manipulating droplet-bouncing behaviors [Li et al., Nat. Phys. 12, 606–612 (2016)]. In this paper, the droplet impact dynamics on the Janus-textured heated substrates are numerically investigated with an improved thermal lattice Boltzmann method. A comprehensive parametric study is conducted by varying the wettability, the Jakob number, the Weber number, and the surface topographies. With different control parameters, three distinct boiling regimes are observed, i.e., the contact boiling regime, the transition boiling regime, and the film boiling regime (Leidenfrost state). To reveal the underlying physics, the distributions of the unbalance Young's force, the thermophoretic force, and the vapor pressure difference in the system are theoretically analyzed. As for the self-propulsion behaviors, it is find that the droplet tends to move toward the denser side (area with more pillar arrays) for the contact boiling regime. However, when the droplet is under the Leidenfrost state, its bouncing dynamics depend on the combined effects of the Weber number and the wettability, and a decrease in wettability induces the droplet to migrate toward the sparser side (area with fewer pillar arrays). These physical insights enrich the fundamental understanding of the droplet-bouncing dynamics on heated substrates and also provide guidelines for designing advanced surfaces to manipulate the droplet-bouncing behavior.
Orbital Hall magnetoresistance in Ni/Ti bilayers
Authors: Hayashi Hiroki , Ando Kazuya
Published: October 2023

We report the observation of the orbital counterpart of the spin Hall magnetoresistance (SMR): the orbital Hall magnetoresistance (OMR). We measured angular-dependent longitudinal magnetoresistance for Ni/Ti bilayer and Ni single-layer films by rotating a magnetic field along three orthogonal planes. When the magnetic field is rotated in the plane perpendicular to the applied current direction, the angular dependence of the magnetoresistance in the Ni/Ti bilayers is consistent with the prediction of the SMR and OMR, whereas that in the Ni single-layer film can be attributed to the geometrical size effect of the anisotropic magnetoresistance. In the Ni/Ti bilayers, the magnetoresistance ratio is found to be five orders of magnitude larger than the prediction of the SMR, indicating that the OMR plays a dominant role in this system.
Spin and valley-polarized multiple Fermi surfaces of
α
-RuCl3/bilayer graphene heterostructure
Authors: Kim Soyun , Hong Jeonghoon , Watanabe Kenji , Taniguchi Takashi , Falson Joseph , Kim Jeongwoo , Kim Youngwook
Published: October 2023

We report the transport properties of α-RuCl3/bilayer graphene heterostructures, where carrier doping is induced by a work function difference, resulting in distinct electron and hole populations in α-RuCl3 and bilayer graphene, respectively. Through a comprehensive analysis of multi-channel transport signatures, including Hall measurements and quantum oscillation, we unveil significant band modifications within the system. In particular, we observe the emergence of spin and valley-polarized multiple hole-type Fermi pockets, originating from the spin-selective band hybridization between α-RuCl3 and bilayer graphene, breaking the spin degree of freedom. Unlike the α-RuCl3/monolayer graphene system, the presence of different hybridization strengths between α-RuCl3 and the top and bottom graphene layers leads to an asymmetric behavior of the two layers, confirmed by effective mass experiments, resulting in the manifestation of valley-polarized Fermi pockets. These compelling findings establish α-RuCl3 proximitized to bilayer graphene as an outstanding platform for engineering its unique low-energy band structure.
Thermal control of polarization of light with nonlocal plasmonic anisotropic metamaterials
Authors: Wu Jingyi , Bykov Anton Yu. , Krasavin Alexey V. , Nasir Mazhar E. , Zayats Anatoly V.
Published: October 2023

Plasmonic nanostructures have demonstrated significant potential for engineering the intensity and polarization state of light with further opportunities to actively manipulate them by external stimulation using nonlinear effects. Plasmonic metamaterials composed of arrays of vertically oriented metallic nanorods have shown a dynamically tunable optical response based on the change of the electron temperature. The modulation of the optical properties is particularly pronounced in the epsilon-near-zero regime and can be further enhanced by nonlocal effects. Here, we experimentally study the optical properties of gold nanorod metamaterials with a strong nonlocal response under optically-induced heating, exploiting temperature dependence of the metal permittivity. Recovering the Stokes parameters of light transmitted through the metamaterial, we demonstrate the change in the polarization of the transmitted light by more than 20% for temperature changes under hundred degrees. Combined with a numerical analysis, this shows the possibility of controlling transmission and polarization state of light by using metamaterial-assisted thermal modulation.
Development of an analytical exponential-6 equation of state through Monte Carlo simulations
Authors: Hallstadius Peter
Published: October 2023

The exponential-6 (exp-6) potential is commonly used to model fluids at high densities. In this paper, I propose a new equation of state (EOS) in the form of an analytical expression for the excess Helmholtz free energy of an exp-6 fluid. The EOS is based on extensive Monte Carlo simulations and therefore combines the excellent accuracy of the simulations with the numerical efficiency of a polynomial expression. The mean relative error in compressibility factor and internal energy is 0.14% and 0.25% respectively, which is a significant improvement over statistical mechanical theories. The EOS was implemented into a thermochemical code in order to optimize gas parameters and evaluate its performance on pure gas data, shock compression and detonation properties. Predicted gas densities, heat capacities and speed of sound for pure gases were generally within experimental uncertainties at pressures up to 1 GPa and temperatures above 300 K. For polar molecules, a simple free energy correction was introduced which greatly improved accuracy at low temperature. Calculated shock Hugoniots showed excellent agreement with experimental values up to 150 GPa and 10 000 K, and the detonation performance was accurately predicted for a number of different types of explosives.
Insight of charge injection barrier at the copper/epoxy resin interface with cross-linking molecules: First-principles calculation and experimental verification
Authors: Ma Diqin , Wang Weiwang , Qu Guanghao , Hu Leiyu , Li Shengtao
Published: October 2023

Understanding charge injection at a metal/cross-linking epoxy resin (EP) interface facilitates the design and application of high-power electric and electronic devices. This paper focuses on the charge injection barrier at the metal/EP interfaces using first-principles calculation. Two fragmentary structures, obtained from cross-linking EP with amine and anhydride curing agent, were selected to construct interface models on a Cu(111) slab. The injection barrier, dipole moment, charge transfer, and vacuum energy level shift (Δ) at the interfaces were examined. The model with the anhydride groups produced higher electron and hole injection barriers than the interface model with the amine groups. The model with the amine groups had a higher Δ, which was derived from molecule dipole and charge transfer. An increase in the work function and Δ caused by an electric field caused an increase in the electron injection barrier and a decrease in the hole injection barrier. Experimental results of the methyl tetrahydrophthalic anhydride cross-linking EP showed a higher charge injection than that of m-phenylenediamine cross-linking EP, providing experimental verification of the theoretical calculation.
Synergistic effect of interface engineering and bulk photovoltaic effect enhanced self-powered Ta2NiS5/
α
-In2Se3/WSe2 van der Waals heterojunction for photodetection
Authors: Tan Shiwen , Hou Pengfei
Published: October 2023

The discovery of van der Waals ferroelectric materials with narrow bandgaps has opened up opportunities for the extensive adoption of self-powered ferroelectric devices that rely on the bulk photovoltaic effect. However, it still needs to overcome the challenges related to the weak ferroelectric polarization and bulk photovoltaic effect in ultrathin van der Waals ferroelectric materials. In this report, we present a synergistic effect of interface engineering and bulk photovoltaic effect in the Ta2NiS5/α-In2Se3/WSe2 van der Waals heterojunction for photodetection. The heterojunction can detect the light with a wide range of wavelengths from near-ultraviolet to near-infrared without requiring external power sources. The output current density of the self-powered heterojunction shows a linear relationship with the optical power intensity at a specific wavelength. Moreover, it accurately identifies the wavelength of light at the same optical power intensity. The on/off ratio is 1.1 × 104, 3.9 × 104, 1 × 104, and 17, respectively, when the optical power density is 100 mW/cm2 for 405, 660, 808, and 1064 nm light. The self-powered Ta2NiS5/α-In2Se3/WSe2 van der Waals photodetector exhibits high specific detectivity of 1.56 × 1011, 1.79 × 1012, 9.16 × 1010, and 1.26 × 105 Jones for wavelengths of 405, 660, 808, and 1064 nm, respectively. These results validate our strategy for enhancing the detection performance in self-powered ferroelectric van der Waals photodetectors, thus opening up possibilities for future self-powered photodetection technologies.
Grain boundary engineering in metavalent SnTe: A simplified approach
Authors: Jakhar Navita , Kedia Dinesh Kumar , Kumar Ankit , Singh Surjeet
Published: October 2023

The metavalently bonded SnTe has gathered enormous attention recently as an environmentally friendly alternative to PbTe. While some of the issues with SnTe, including its small bandgap and large valence band offset, have largely been resolved, its relatively high lattice thermal conductivity (κl) has remained a matter of concern. Here, we show that the temperature-induced vacancy migration in SnTe results in the growth of SnTe nanoparticles in the intergrain region. The enhanced grain boundary scattering due to this led to a highly reduced κl and increased carrier mobility, enhancing the zT of our SnTe by almost 70% over the zT of various SnTe ingot samples from this and several previous studies. The validity of this approach was further confirmed for a 3% Ag-doped SnTe sample, a composition well-investigated in the past. The simplicity and effectiveness of our approach enhance the prospect of SnTe for practical applications.
Revealing the missing puzzle piece of concentration in regulating Zn electrodeposition
Authors: Zhao Zhongxi , He Yi , Yu Wentao , Shang Wenxu , Ma Yanyi , Tan Peng
Published: October 2023

Despite achievements in suppressing dendrites and regulating Zn crystal growth, secondary aqueous Zn batteries are still rare in the market. Existing strategies mainly focus on electrode modification and electrolyte optimization, while the essential role of ion concentration in liquid-to-solid electrodeposition is neglected for a long time. Herein, the mechanism of concentration regulation in Zn electrodeposition is investigated in depth by combining electrochemical tests, post hoc characterization, and multiscale simulations. First, initial Zn electrodeposition is thermodynamically controlled epitaxial growth, whereas with the rapid depletion of ions, the concentration overpotential transcends the thermodynamic influence to kinetic control. Then, the evolution of the morphology from 2D sheets to 1D whiskers due to the concentration change is insightfully revealed by the morphological characterization and phase-field modeling. Furthermore, the depth of discharge (DOD) results in large concentration differences at the electrode–electrolyte interface, with a mild concentration distribution at lower DOD generating (002) crystal plane 2D sheets and a heavily varied concentration distribution at higher DOD yielding arbitrarily oriented 3D blocks. As a proof of concept, relaxation is introduced into two systems to homogenize the concentration distribution, revalidating the essential role of concentration in regulating electrodeposition, and two vital factors affecting the relaxation time, i.e., current density and electrode distance, are deeply investigated, demonstrating that the relaxation time is positively related to both and is more sensitive to the electrode distance. This work contributes to reacquainting aqueous batteries undergoing phase transitions and reveals a missing piece of the puzzle in regulating Zn electrodeposition.
Triggering photocatalytic performance of La
2
Co
x
Mn
2-x
O
6
via heat activation
Authors: Chen Cheng , Wu Mingge , Chen Bolei , Ma Chunyan , Song Maoyong , Jiang Guibin
Published: October 2023

The La-based perovskite (LaBO
3
) exhibits excellent optical properties. However, its valence band (VB) potential is not sufficiently positive to reach the oxidation potential required for the cleavage of chemical bonds (such as benzylic C–H), limiting its application in photocatalysis. Herein, we report the unconventional effects of heat activation on the reduction of the dissociation energy of benzylic C–H and aqueous H–O, thereby triggering the photocatalytic activity of La
2
Co
x
Mn
2-x
O
6
perovskites. Additionally, we demonstrate that photocatalysis is the main contributor to substrate conversion in the selective oxidation of toluene and reduction of CO
2
. Particularly, La
2
Co
1.5
Mn
0.5
O
6
shows excellent performance with a product yield of 550.00 mmol g
cat
−1
and a toluene conversion of 22,866.67 μmol g
cat
−1
h
−1
. To the best of our knowledge, this is the highest reported product yield for the selective oxidation of benzylic C–H bond of toluene. Our findings provide insight into the specific role of heat activation in photocatalysis, which is crucial for breaking and overcoming the VB barrier to realize challenging reactions.
Emergent properties of melanin-inspired peptide/RNA condensates
Authors: Netzer Amit , Katzir Itai , Baruch Leshem Avigail , Weitman Michal , Lampel Ayala
Published: October 2023

Most biocatalytic processes in eukaryotic cells are regulated by subcellular microenvironments such as membrane-bound or membraneless organelles. These natural compartmentalization systems have inspired the design of synthetic compartments composed of a variety of building blocks. Recently, the emerging field of liquid–liquid phase separation has facilitated the design of biomolecular condensates composed of proteins and nucleic acids, with controllable properties including polarity, diffusivity, surface tension, and encapsulation efficiency. However, utilizing phase-separated condensates as optical sensors has not yet been attempted. Here, we were inspired by the biosynthesis of melanin pigments, a key biocatalytic process that is regulated by compartmentalization in organelles, to design minimalistic biomolecular condensates with emergent optical properties. Melanins are ubiquitous pigment materials with a range of functionalities including photoprotection, coloration, and free radical scavenging activity. Their biosynthesis in the confined melanosomes involves oxidation-polymerization of tyrosine (Tyr), catalyzed by the enzyme tyrosinase. We have now developed condensates that are formed by an interaction between a Tyr-containing peptide and RNA and can serve as both microreactors and substrates for tyrosinase. Importantly, partitioning of Tyr into the condensates and subsequent oxidation-polymerization gives rise to unique optical properties including far-red fluorescence. We now demonstrate that individual condensates can serve as sensors to detect tyrosinase activity, with a limit of detection similar to that of synthetic fluorescent probes. This approach opens opportunities to utilize designer biomolecular condensates as diagnostic tools for various disorders involving abnormal enzymatic activity.
Efficient Bayesian inference under the multispecies coalescent with migration
Authors: Flouri Tomáš , Jiao Xiyun , Huang Jun , Rannala Bruce , Yang Ziheng
Published: October 2023

Analyses of genome sequence data have revealed pervasive interspecific gene flow and enriched our understanding of the role of gene flow in speciation and adaptation. Inference of gene flow using genomic data requires powerful statistical methods. Yet current likelihood-based methods involve heavy computation and are feasible for small datasets only. Here, we implement the multispecies-coalescent-with-migration model in the Bayesian programbpp, which can be used to test for gene flow and estimate migration rates, as well as species divergence times and population sizes. We develop Markov chain Monte Carlo algorithms for efficient sampling from the posterior, enabling the analysis of genome-scale datasets with thousands of loci. Implementation of both introgression and migration models in the same program allows us to test whether gene flow occurred continuously over time or in pulses. Analyses of genomic data fromAnophelesmosquitoes demonstrate rich information in typical genomic datasets about the mode and rate of gene flow.
Hansard at Huddersfield
Authors: Jeffries Lesley , Stradling Fransina , Lünen Alex von , Sanjurjo-González Hugo
Published: October 2023

This chapter describes one project’s approach to
fostering uptake of corpus tools in research beyond corpus linguistics. It
introduces the Hansard at Huddersfield web application, a new search tool
that combines tried-and-tested corpus tools with interactive visualisations
to make Hansard, the official record of the UK parliament (1803–2021), more
accessible for in-depth study by non-specialists. The chapter outlines the
thinking behind and development of the Hansard at Huddersfield web interface
and exemplifies how the site’s adapted corpus tools offer non-linguists new
entry points for Hansard research through three small sample studies. It
further reflects on the process of preparing the large Hansard corpus to
allow insights to be gleaned from corpus-style searches by researchers with
relatively little training.
From criminal lunacy to mental disorder
Authors: Nevala Minna , Tyrkkö Jukka
Published: October 2023

This chapter investigates discourses of mental health in
the British parliament over two centuries (1800–2020). A pattern-driven
approach is used to explore terminology related to mentally ill people,
mental institutions, and mental health in general. The study focuses on
lexical trends in parliamentary discourse, the extent to which mental health
discourse was discussed in general, and the way in which the lexis of modern
mental health care has developed. The results show that the major shifts in
the entire lexical field have happened in specific time periods, the turning
points being in the 1840s, 1930s and 1950s. The general attitude also seems
to have shifted, and the data show an increasing concern for legally
protecting people with mental illness.
Colloquialisation, compression and democratisation in British parliamentary debates
Authors: Schneider Gerold , Reveilhac Maud
Published: October 2023

We conduct an analysis of the link between
colloquialisation and democratisation in debates in the British parliament.
Our corpus is a sampler of the Hansard archive, covering the period
1803–2005 and containing 170 million words. We first investigate how the
linguistic patterns of parliamentary debates have evolved, and second how
the content of the debates has changed over time. Combining these two
research questions allows us to step to a third question: are there direct
relations between linguistic features, most notably colloquialisation and
compression of language, and the topical content of parliamentary discourse,
particularly its underpinnings in social and political democratisation
processes? We also critically discuss strong correlations between features
of language complexity and democracy indices. We adopt an interdisciplinary
perspective embedded in both linguistics and political sciences.
Myosin and tropomyosin–troponin complementarily regulate thermal activation of muscles
Authors: Ishii Shuya , Oyama Kotaro , Kobirumaki-Shimozawa Fuyu , Nakanishi Tomohiro , Nakahara Naoya , Suzuki Madoka , Ishiwata Shin’ichi , Fukuda Norio
Published: October 2023

Contraction of striated muscles is initiated by an increase in cytosolic Ca2+ concentration, which is regulated by tropomyosin and troponin acting on actin filaments at the sarcomere level. Namely, Ca2+-binding to troponin C shifts the “on–off” equilibrium of the thin filament state toward the “on” state, promoting actomyosin interaction; likewise, an increase in temperature to within the body temperature range shifts the equilibrium to the on state, even in the absence of Ca2+. Here, we investigated the temperature dependence of sarcomere shortening along isolated fast skeletal myofibrils using optical heating microscopy. Rapid heating (25 to 41.5°C) within 2 s induced reversible sarcomere shortening in relaxing solution. Further, we investigated the temperature-dependence of the sliding velocity of reconstituted fast skeletal or cardiac thin filaments on fast skeletal or β-cardiac myosin in an in vitro motility assay within the body temperature range. We found that (a) with fast skeletal thin filaments on fast skeletal myosin, the temperature dependence was comparable to that obtained for sarcomere shortening in fast skeletal myofibrils (Q10 ∼8), (b) both types of thin filaments started to slide at lower temperatures on fast skeletal myosin than on β-cardiac myosin, and (c) cardiac thin filaments slid at lower temperatures compared with fast skeletal thin filaments on either type of myosin. Therefore, the mammalian striated muscle may be fine-tuned to contract efficiently via complementary regulation of myosin and tropomyosin–troponin within the body temperature range, depending on the physiological demands of various circumstances.
Multiscale hierarchical decomposition methods for ill-posed problems
Authors: Kindermann Stefan , Resmerita Elena , Wolf Tobias
Published: October 2023

The multiscale hierarchical decomposition method (MHDM) was introduced in Tadmor et al (2004 Multiscale Model. Simul.
2 554–79; 2008 Commun. Math. Sci.
6 281–307) as an iterative method for total variation (TV) regularization, with the aim of recovering details at various scales from images corrupted by additive or multiplicative noise. Given its success beyond image restoration, we extend the MHDM iterates in order to solve larger classes of linear ill-posed problems in Banach spaces. Thus, we define the MHDM for more general convex or even nonconvex penalties, and provide convergence results for the data fidelity term. We also propose a flexible version of the method using adaptive convex functionals for regularization, and show an interesting multiscale decomposition of the data. This decomposition result is highlighted for the Bregman iteration method that can be expressed as an adaptive MHDM. Furthermore, we state necessary and sufficient conditions when the MHDM iteration agrees with the variational Tikhonov regularization, which is the case, for instance, for one-dimensional TV denoising. Finally, we investigate several particular instances and perform numerical experiments that point out the robust behavior of the MHDM.