bluuebunny/crossref_metadata_2025 huggingface dataset:
Transient chimera states emerging from dynamical trapping in chaotic saddles
Authors: Medeiros Everton S. , Omel’chenko Oleh , Feudel Ulrike
Published: September 2023

Nonlinear systems possessing nonattracting chaotic sets, such as chaotic saddles, embedded in their state space may oscillate chaotically for a transient time before eventually transitioning into some stable attractor. We show that these systems, when networked with nonlocal coupling in a ring, are capable of forming chimera states, in which one subset of the units oscillates periodically in a synchronized state forming the coherent domain, while the complementary subset oscillates chaotically in the neighborhood of the chaotic saddle constituting the incoherent domain. We find two distinct transient chimera states distinguished by their abrupt or gradual termination. We analyze the lifetime of both chimera states, unraveling their dependence on coupling range and size. We find an optimal value for the coupling range yielding the longest lifetime for the chimera states. Moreover, we implement transversal stability analysis to demonstrate that the synchronized state is asymptotically stable for network configurations studied here.
On the conserved quantities in an Einstein-scalar system
Authors: He Xiaokai , Cao Zhoujian
Published: September 2023

The generalization of ten conserved quantities (Newman–Penrose constants) defined in asympotically flat vacuum spacetimes to asymptotically flat Einstein-scalar spacetimes is studied. It is found that these quantites, when suitably modified, are also conserved in a Einstein-scalar system.
Electromagnetic scattering characteristics of a hypersonic vehicle with a microrough surface in the millimeter wave band
Authors: Zhang Haifeng , Li Jiangting , Qiu Changkui , Yu Zhefeng , Bian Zheng , Guo Lixin , Guo Linjing , Liu Songhua
Published: September 2023

The rough structure may affect the flow field and electromagnetic (EM) scattering characteristics of a hypersonic vehicle. In this study, the EM scattering characteristics of the hypersonic vehicle RAM C-II with a microrough surface were investigated in the millimeter wave band. We first simulated the flow field of a smooth RAM C-II vehicle and calculated the radar cross section (RCS) in the wideband using the physical optics method. The calculation results show that many factors contribute to the variation in the RCS; however, it is occasionally difficult to predict. We then used a one-dimensional Gaussian random rough surface to generate a RAM C-II with a microrough surface through a point-coordinate transformation and simulated its flow field. The electron density flow field of the rough surfaced aircraft fluctuates greatly on the wall. Finally, we calculated the RCS of RAM C-II with different values of roughness in the millimeter wave band. The change of surface structure can be reflected in millimeter waves, and the RCS is determined by both plasma and rough structure.
Surface hopping, electron translation factors, electron rotation factors, momentum conservation, and size consistency
Authors: Athavale Vishikh , Bian Xuezhi , Tao Zhen , Wu Yanze , Qiu Tian , Rawlinson Jonathan , Littlejohn Robert G. , Subotnik Joseph E.
Published: September 2023

For a system without spin–orbit coupling, the (i) nuclear plus electronic linear momentum and (ii) nuclear plus orbital electronic angular momentum are good quantum numbers. Thus, when a molecular system undergoes a nonadiabatic transition, there should be no change in the total linear or angular momentum. Now, the standard surface hopping algorithm ignores the electronic momentum and indirectly equates the momentum of the nuclear degrees of freedom to the total momentum. However, even with this simplification, the algorithm still does not conserve either the nuclear linear or the nuclear angular momenta. Here, we show that one way to address these failures is to dress the derivative couplings (i.e., the hopping directions) in two ways: (i) we disallow changes in the nuclear linear momentum by working in a translating basis (which is well known and leads to electron translation factors) and (ii) we disallow changes in the nuclear angular momentum by working in a basis that rotates around the center of mass [which is not well-known and leads to a novel, rotationally removable component of the derivative coupling that we will call electron rotation factors below, cf. Eq. (96)]. The present findings should be helpful in the short term as far as interpreting surface hopping calculations for singlet systems (without spin) and then developing the new surface hopping algorithm in the long term for systems where one cannot ignore the electronic orbital and/or spin angular momentum.
Confinement of non-neutral proton plasma within a bent magnetic mirror field: 3D PIC simulation
Authors: Zhang Xiao-Jing , Sun Yong , Chen Liang-Wen , Wang Fang-Ping , Duan Wen-Shan
Published: September 2023

We conducted a study on the confinement properties of non-neutral proton plasma in an asymmetric magnetic mirror using the three-dimensional (3D) particle-in-cell simulation method. Our findings indicate a close relationship between the ability of the magnetic mirror to confine protons and the incidence orientation of the proton beam. This relationship can only be accurately assessed through 3D simulation, as opposed to two-dimensional simulation. In addition, we observed that a higher velocity parallel to the magnetic field direction results in a shorter confinement time. The electric field at and near the central point of the mirror exhibits quasi-periodic vibrations, attributed to the electrostatic oscillation of the proton and the cyclotron motion. Furthermore, we discovered a drift motion of the confined proton plasma in the direction of the magnetic field gradient. These findings hold implications for the design of magnetic mirrors capable of effectively confining charged particle beams.
Directional migration of impacting droplets on hydrophobic-superhydrophobic boundary
Authors: Xing Lei , Guan Shuai , Jiang Minghu , Shi Longlong
Published: September 2023

Directional transportation of droplets plays a crucial role in the fields of anti-fog, anti-icing, material transportation, and several other applications. Herein, the total directional transport of droplets on a surface with controllable wettability was numerically investigated by the level set method coupled with the volume of fluid method. The accuracy of the numerical simulation results was validated via high-speed photography experiments. The directional migration and morphological evolution mechanisms of droplets impacting on the superhydrophobic–hydrophobic interface were revealed. Moreover, the effects of the impacting position on the directional migration velocity, rebound height, and transport distance of droplets were systematically analyzed. Theoretical models were derived for predicting the transport distance and rebound height of droplets. The simulation results reveal that, for a droplet impacting on the superhydrophobic and hydrophobic interface, four stages exist, i.e., spreading, contraction, rebound, and directional migration, which differ from those for a droplet impacting on a normal surface. It is thus deduced that the adhesion length is a significant factor that affects the directional migration parameters. Moreover, there exists an optimal adhesion length for the impacting droplet, under which the transport distance can be maximized. The maximum transport distance of the droplet under the optimal adhesion length is 12 mm. Furthermore, the values predicted by using the theoretical models agree well with the actual ones, proving the feasibility of the prediction models. The results contribute to the fundamental theory of droplet directional migration and are valuable for related engineering applications.
Response to comment on “Stability of a moving radial liquid sheet: Time-dependent equations” [Phys. Fluids 35, 099101 (2023)]
Authors: Tirumkudulu Mahesh S.
Published: September 2023

In a recent comment, Mehring and Gyurkovich show that in our derivation of the time-dependent equations, we have neglected the perturbed term in the interface location while applying the kinematic boundary condition. When the neglected term is incorporated in the analysis, the time-dependent equation for the sinuous mode is different from our original expression. They conclude that the instability predicted by the original model does not exist for their new model. We show that, on the contrary, the new model predicts spatial growth of sinuous disturbance that depends on forcing frequency and the slope of the forcing disturbance.
The propagation characteristics of low frequency radio waves in magnetized hypersonic plasma sheaths
Authors: Mao Mingyang , Yuan Kai , Tang Rongxin , Xiong Jiawei , Zhao Ziyang , Deng Xiaohua
Published: September 2023

Communication blackouts have been a main threat to hypersonic vehicles for decades. The low frequency communication was considered a potential approach to mitigate the “blackout.” Nowadays, low frequency transmitters serving underwater communication have transmission power up to several megawatts. In other words, if low frequency communication signals could penetrate the plasma sheath, it would be a meaningful solution that using modern low frequency transmitters to give service to hypersonic vehicle communication, and the service area could be very large. Although the studies on blackouts using low frequency waves have lasted for many years, it still remains many unclear problems. The present study analyzes the characteristics of different frequency waves passing through a plasma sheath. The analysis revealed that the low frequency signals with high power could penetrate the plasma sheath and mitigate the blackout effectively. According to our simulation results, the transmission coefficient decreased with the flight speed and also increased with magnetic field intensity and the axial distance from the onboard antenna to the nose of the vehicle. Moreover, it is not sensitive to the frequency of signals. At last, two example models of using a ground low frequency station to communicate with the hypersonic vehicle were analyzed, which means that the low frequency communication can significantly be considered in the application of hypersonic vehicles in the near future.
A unified thermodynamic/Lamb-vector-based analysis of the aerodynamic force
Authors: Minervino Mauro , Tognaccini Renato
Published: September 2023

The Lamb vector, cross-product of flow vorticity and velocity, is at the basis of different far-field methods developed in the last decades for the aerodynamic force analysis and decomposition, as an alternative to the nowadays well-assessed thermodynamic methods. We here propose a mixed approach, where exact Lamb-vector-based force formulas are used in combination with a thermodynamic-based calculation of the Lamb vector through Crocco's equation. In computational fluid dynamics, this way of calculating the Lamb vector, therefore, inherits from the numerical form of the flow momentum equation and discretely satisfies the local (and integral) momentum balance on which far-field methods rely. The resulting hybrid method, which does not require an explicit vorticity calculation, provides results in far better agreement with regard to near-field force data when compared to standard vorticity-based approaches, especially in the presence of shock waves, where inaccuracies of domain integrals involving the Lamb vector were systematically reported by different authors. In addition, it overcomes the limitations of previous thermodynamic methods, which only compute the drag force.
A note on the summation relation in phase-field equations
Authors: Haghani Reza , Erfani Hamidreza , McClure James E. , Berg Carl Fredrik
Published: September 2023

In this paper, we investigate phase-field interface capturing equations for two-fluid systems to probe their accuracy and computational cost. Two different schemes are considered: In the first scheme, one of the two order parameters is numerically solved based on a phase-field equation, while the other order parameter is determined through the summation relation; the summation of order parameters equals unity. In the second scheme, the two order parameters are both obtained numerically by solving their respective phase-field equations. A phase-field model based on the color-gradient (CG) method is chosen, and available lattice Boltzmann models are employed for solving the interface-capturing equations together with the hydrodynamic equation. It is shown that for the first scheme, which includes the summation relation, numerical results become asymmetrical. Also, in some cases, it results in nonphysical interfaces. In terms of computational resources, this first scheme is about 11% faster with 25% less computational memory usage than the second scheme. It is shown that only for a zero velocity domain do the two schemes lead to equal results. Also, a theoretical analysis is conducted to highlight the differences between the two approaches.
Tunable flatband plasmonic quasi-bound states in the continuum based on graphene-assisted metasurfaces
Authors: Wang Zhuo , Wang Yue , Cheng Zhi , Qu Jiaqi , Cui Mingjie , Huang Dongmei , Yu Changyuan
Published: September 2023

Bound states in the continuum (BICs) of plasmonic systems offer a powerful method for enhancing light–matter interaction at the nanoscale. The recent emergence of flatband quasi-BICs has alleviated the limitation of the incident angle of the excitation light on generating high-quality-factor (high-Q-factor) resonances, which makes it feasible to produce substantial near-field enhancement by focused light. However, the current works are limited to passive systems with fixed amplitude and Q-factor, hindering the dynamic tunability of light field enhancement. Here, we design a plasmonic metasurface integrated with monolayer graphene to achieve tunable flatband quasi-BICs. Under the illumination of a tightly focused transverse-magnetic wave, our simulations show that adjusting the chemical potential of graphene can increase Q-factor from 52.5 to 75.9 and improve absorption amplitude from 81% to 95%. These results pave the way for dynamically adjustable near-field enhancement with tightly focused light.
Optimal parameterizing manifolds for anticipating tipping points and higher-order critical transitions
Authors: Chekroun Mickaël D. , Liu Honghu , McWilliams James C.
Published: September 2023

A general, variational approach to derive low-order reduced models from possibly non-autonomous systems is presented. The approach is based on the concept of optimal parameterizing manifold (OPM) that substitutes more classical notions of invariant or slow manifolds when the breakdown of “slaving” occurs, i.e., when the unresolved variables cannot be expressed as an exact functional of the resolved ones anymore. The OPM provides, within a given class of parameterizations of the unresolved variables, the manifold that averages out optimally these variables as conditioned on the resolved ones. The class of parameterizations retained here is that of continuous deformations of parameterizations rigorously valid near the onset of instability. These deformations are produced through the integration of auxiliary backward–forward systems built from the model’s equations and lead to analytic formulas for parameterizations. In this modus operandi, the backward integration time is the key parameter to select per scale/variable to parameterize in order to derive the relevant parameterizations which are doomed to be no longer exact away from instability onset due to the breakdown of slaving typically encountered, e.g., for chaotic regimes. The selection criterion is then made through data-informed minimization of a least-square parameterization defect. It is thus shown through optimization of the backward integration time per scale/variable to parameterize, that skilled OPM reduced systems can be derived for predicting with accuracy higher-order critical transitions or catastrophic tipping phenomena, while training our parameterization formulas for regimes prior to these transitions takes place.
Numerical simulation of an electromagnetic squeezing hybrid nanofluid flow through permeable plates with sensor monitoring system
Authors: Rammoorthi Rajakumari , Mohanavel Dhivya
Published: September 2023

The primary aim of this study is to examine the effect of squeezing hybrid nanofluids copper and magnetite with water flow across a horizontal surface under the impact of magnetic and radiative effects, which has extensive applications in the field of biomedical engineering and nanotechnology. Additionally, a microcantilever sensor is placed between the horizontal surfaces to surveil the flow behaviors. The equations pertaining to momentum and energy are reconstructed into a set of ordinary differential equations (ODEs). These ODEs are subsequently solved through a numerical approach, wherein the bvp4c solver from MATLAB is utilized. This solver employs a collocation technique for the numerical solution. As a result, the solutions acquired for velocity and temperature are graphically displayed for different parameters, including volume fraction of nanoparticles, squeezing flow index parameter (b), magnetic parameter (M), permeable velocity parameter (f0), radiation parameter R, and Prandtl number (Pr). It has been observed that increasing the magnetic effect as well as the volume fraction of nanoparticles strengthens the flow effect. In contrast, increasing the squeezing and permeable velocity parameter impedes the flow. When there is an increase in a permeable velocity parameter, the temperature shoots up, and the cooling effect is spotted in the temperature profile, when the Prandtl number and magnetic and squeezing parameters are raised. This investigation upholds the significance of drag reduction, flow instabilities, fluid structure interactions, and heat transfer effectiveness by virtue of wall shear stress, squeezing flow index parameter, various hybrid nanofluids, and Nusselt number, respectively. A considerable comparative study has been made for the validation of current results.
Dynamic contact angle measurement of hydrophilic open microchannels: The role of surface wettability
Authors: Xian Zhaokun , Du Zuohao , Chen Yuanfen , Liu Liming , You Hui
Published: September 2023

Wetting dynamics play a major role in many practical applications; however, many fundamental problems remain unresolved, especially in relation to the dynamic contact angle. The present study investigates the movement of a gas–liquid interface in an open microchannel with different materials and wettability. Using a high-speed microscope camera, the shape of the dynamic equilibrium of the gas–liquid interface in a flowing state was recorded, including the microscopic regions near the contact line. The results show that the effects of the surface wetting condition play a crucial role in altering the apparent dynamic contact angle. During the experiment, we observed an interesting phenomenon where the dynamic equilibrium contact angle under flow conditions is larger than the contact angle predicted by the Cox–Voinov law. This may be attributed to the existence of friction between the fluid and the wall surface under flow, which reduces the additional pressure at the gas–liquid interface, and the magnitude of friction is manifested through the hysteresis contact angle. The instability and periodic variation of the microscopic contact angle are caused by the surface heterogeneity near the contact line, namely, the spatial variation of solid–gas and solid–liquid interfacial tensions. Understanding the surface properties can help optimize the interface system's design and improve its efficiency for use.
Controlling emission energy in metal–organic frameworks featuring cyclometalated iridium(III) linkers
Authors: Hua Carol , Connell Timothy U.
Published: September 2023

Efficient solid-state luminescent materials are critical components in varied optoelectronic devices. Here, we report three metal–organic frameworks combining calcium(II) with heteroleptic iridium(III) metalloligands containing the same 1,2-diimine ancillary ligand but different cyclometalating ligands. The synthesised frameworks exhibit similar supramolecular structure but different emission properties depending on the cyclometalating ligand. Binding calcium(II) to the metalloligands further affects framework emission depending on the relative contribution of triplet charge transfer (3MLLCT) or ligand-centred (3LC) transitions to the emissive excited state.
HMGB1 released by mesothelial cells drives the development of asbestos-induced mesothelioma
Authors: Suarez Joelle S. , Novelli Flavia , Goto Keisuke , Ehara Michiko , Steele Mika , Kim Jin-Hee , Zolondick Alicia A. , Xue Jiaming , Xu Ronghui , Saito Mai , Pastorino Sandra , Minaai Michael , Takanishi Yasutaka , Emi Mitsuru , Pagano Ian , Wakeham Andrew , Berger Thorsten , Pass Harvey I. , Gaudino Giovanni , Mak Tak W. , Carbone Michele , Yang Haining
Published: September 2023

Asbestos is the main cause of malignant mesothelioma. Previous studies have linked asbestos-induced mesothelioma to the release of HMGB1 from the nucleus to the cytoplasm, and from the cytoplasm to the extracellular space. In the cytoplasm, HMGB1 induces autophagy impairing asbestos-induced cell death. Extracellularly, HMGB1 stimulates the secretion of
TNFα
. Jointly, these two cytokines kick-start a chronic inflammatory process that over time promotes mesothelioma development. Whether the main source of extracellular HMGB1 were the mesothelial cells, the inflammatory cells, or both was unsolved. This information is critical to identify the targets and design preventive/therapeutic strategies to interfere with asbestos-induced mesothelioma. To address this issue, we developed the conditional mesothelial HMGB1-knockout (
Hmgb1
ΔpMeso
) and the conditional myelomonocytic-lineage HMGB1-knockout (
Hmgb1
ΔMylc
) mouse models. We establish here that HMGB1 is mainly produced and released by the mesothelial cells during the early phases of inflammation following asbestos exposure. The release of HMGB1 from mesothelial cells leads to atypical mesothelial hyperplasia, and in some animals, this evolves over the years into mesothelioma. We found that
Hmgb1
ΔpMeso
, whose mesothelial cells cannot produce HMGB1, show a greatly reduced inflammatory response to asbestos, and their mesothelial cells express and secrete significantly reduced levels of
TNFα
. Moreover, the tissue microenvironment in areas of asbestos deposits displays an increased fraction of M1-polarized macrophages compared to M2 macrophages. Supporting the biological significance of these findings,
Hmgb1
ΔpMeso
mice showed a delayed and reduced incidence of mesothelioma and an increased mesothelioma-specific survival. Altogether, our study provides a biological explanation for HMGB1 as a driver of asbestos-induced mesothelioma.
Shedding light on rechargeable Na/Cl
2
battery
Authors: Zhu Guanzhou , Liang Peng , Huang Cheng-Liang , Wu Shu-Chi , Huang Cheng-Chia , Li Yuan-Yao , Jiang Shi-Kai , Huang Wei-Hsiang , Li Jiachen , Wang Feifei , Hwang Bing-Joe , Dai Hongjie
Published: September 2023

Advancing new ideas of rechargeable batteries represents an important path to meeting the ever-increasing energy storage needs. Recently, we showed rechargeable sodium/chlorine (Na/Cl
2
) (or lithium/chlorine Li/Cl
2
) batteries that used a Na (or Li) metal negative electrode, a microporous amorphous carbon nanosphere (aCNS) positive electrode, and an electrolyte containing dissolved aluminum chloride and fluoride additives in thionyl chloride [G. Zhu
et al.
,
Nature
596
, 525–530 (2021) and G. Zhu
et al.
,
J. Am. Chem. Soc.
144
, 22505–22513 (2022)]. The main battery redox reaction involved conversion between NaCl and Cl
2
trapped in the carbon positive electrode, delivering a cyclable capacity of up to 1,200 mAh g
−1
(based on positive electrode mass) at a ~3.5 V discharge voltage [G. Zhu
et al.
,
Nature
596
, 525–530 (2021) and G. Zhu
et al.
,
J. Am. Chem. Soc.
144
, 22505–22513 (2022)]. Here, we identified by X-ray photoelectron spectroscopy (XPS) that upon charging a Na/Cl
2
battery, chlorination of carbon in the positive electrode occurred to form carbon-chlorine (C-Cl) accompanied by molecular Cl
2
infiltrating the porous aCNS, consistent with Cl
2
probed by mass spectrometry. Synchrotron X-ray diffraction observed the development of graphitic ordering in the initially amorphous aCNS under battery charging when the carbon matrix was oxidized/chlorinated and infiltrated with Cl
2
. The C-Cl, Cl
2
species and graphitic ordering were reversible upon discharge, accompanied by NaCl formation. The results revealed redox conversion between NaCl and Cl
2
, reversible graphitic ordering/amorphourization of carbon through battery charge/discharge, and probed trapped Cl
2
in porous carbon by XPS.
UHRF1 promotes spindle assembly and chromosome congression by catalyzing EG5 polyubiquitination
Authors: Qi Xuli , Liu Youhong , Peng Yuchong , Fu Yuxin , Fu Yongming , Yin Linglong , Li Xiong
Published: September 2023

UHRF1 is an epigenetic coordinator bridging DNA methylation and histone modifications. Additionally, UHRF1 regulates DNA replication and cell cycle, and its deletion induces G1/S or G2/M cell cycle arrest. The roles of UHRF1 in the regulation of G2/M transition remain poorly understood. UHRF1 depletion caused chromosome misalignment, thereby inducing cell cycle arrest at mitotic metaphase, and these cells exhibited the defects of spindle geometry, prominently manifested as shorter spindles. Mechanistically, UHRF1 protein directly interacts with EG5, a kinesin motor protein, during mitosis. Furthermore, UHRF1 induced EG5 polyubiquitination at the site of K1034 and further promoted the interaction of EG5 with spindle assembly factor TPX2, thereby ensuring accurate EG5 distribution to the spindles during metaphase. Our study clarifies a novel UHRF1 function as a nuclear protein catalyzing EG5 polyubiquitination for proper spindle architecture and faithful genomic transmission, which is independent of its roles in epigenetic regulation and DNA damage repair inside the nucleus. These findings revealed a previously unknown mechanism of UHRF1 in controlling mitotic spindle architecture and chromosome behavior and provided mechanistic evidence for UHRF1 deletion-mediated G2/M arrest.
Identifying biomarkers of heterogeneity and transplantation efficacy in retinal pigment epithelial cells
Authors: Farjood Farhad , Manos Justine D. , Wang Yue , Williams Anne L. , Zhao Cuiping , Borden Susan , Alam Nazia , Prusky Glen , Temple Sally , Stern Jeffrey H. , Boles Nathan C.
Published: September 2023

Transplantation of retinal pigment epithelial (RPE) cells holds great promise for patients with retinal degenerative diseases, such as age-related macular degeneration. In-depth characterization of RPE cell product identity and critical quality attributes are needed to enhance efficacy and safety of replacement therapy strategies. Here, we characterized an adult RPE stem cell–derived (RPESC-RPE) cell product using bulk and single-cell RNA sequencing (scRNA-seq), assessing functional cell integration in vitro into a mature RPE monolayer and in vivo efficacy by vision rescue in the Royal College of Surgeons rats. scRNA-seq revealed several distinct subpopulations in the RPESC-RPE product, some with progenitor markers. We identified RPE clusters expressing genes associated with in vivo efficacy and increased cell integration capability. Gene expression analysis revealed lncRNA (TREX) as a predictive marker of in vivo efficacy. TREX knockdown decreased cell integration while overexpression increased integration in vitro and improved vision rescue in the RCS rats.
Disease-associated KCNMA1 variants decrease circadian clock robustness in channelopathy mouse models
Authors: Dinsdale Ria L. , Roache Cooper E. , Meredith Andrea L.
Published: September 2023

KCNMA1 encodes the voltage- and calcium-activated K+ (BK) channel, which regulates suprachiasmatic nucleus (SCN) neuronal firing and circadian behavioral rhythms. Gain-of-function (GOF) and loss-of-function (LOF) alterations in BK channel activity disrupt circadian behavior, but the effect of human disease-associated KCNMA1 channelopathy variants has not been studied on clock function. Here, we assess circadian behavior in two GOF and one LOF mouse lines. Heterozygous Kcnma1N999S/WT and homozygous Kcnma1D434G/D434G mice are validated as GOF models of paroxysmal dyskinesia (PNKD3), but whether circadian rhythm is affected in this hypokinetic locomotor disorder is unknown. Conversely, homozygous LOF Kcnma1H444Q/H444Q mice do not demonstrate PNKD3. We assessed circadian behavior by locomotor wheel running activity. All three mouse models were rhythmic, but Kcnma1N999S/WT and Kcnma1D434G/D434G showed reduced circadian amplitude and decreased wheel activity, corroborating prior studies focused on acute motor coordination. In addition, Kcnma1D434G/D434G mice had a small decrease in period. However, the phase-shifting sensitivity for both GOF mouse lines was abnormal. Both Kcnma1N999S/WT and Kcnma1D434G/D434G mice displayed increased responses to light pulses and took fewer days to re-entrain to a new light:dark cycle. In contrast, the LOF Kcnma1H444Q/H444Q mice showed no difference in any of the circadian parameters tested. The enhanced sensitivity to phase-shifting stimuli in Kcnma1N999S/WT and Kcnma1D434G/D434G mice was similar to other Kcnma1 GOF mice. Together with previous studies, these results suggest that increasing BK channel activity decreases circadian clock robustness, without rhythm ablation.
Final report of APMP.AUV.V-K3.1: Key comparison in the field of acceleration on the complex voltage sensitivity
Authors: Tu Tsung-Hsien , Kuo Shu-Fen , Chen Jiun-Kai , Yang Lifeng , Rattanangkul Pairoj , Lee Yong-Bong , Veldman Ian , Garg Naveen , Hung Chen-Yun
Published: September 2023

Main text

This report presents the results of the APMP comparison in the area of 'vibration', which here refers to the calibration of the accelerometer standards set in compliance with method 1 or method 3 as recommended in the international standard ISO 16063-11:1999.The participants have reached a consensus and considered the most appropriate method, then referred to CCAUV.V-K3 report, the weighted mean and the degrees of equivalence were evaluated for this particular comparison. The calculation of the key weighted mean was in accordance with the Guidelines for CIPM key comparisons.The "linking" procedure was applied to establish the relationship between the results of the participants and those of the CIPM comparison in the field of vibration, which was CCAUV.V-K3. Only one pilot laboratory, NIM, acted as the linking laboratory. The linking factors were defined as the ratio and difference for magnitude and phase shift respectively through the NIM results in CCAUV.V-K3 and APMP.AUV.V-K3.1. Using the linking factors, this RMO results of six participants were directly compared with the results of CCAUV.V-K3.

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

The final report has been peer-reviewed and approved for publication by the CCAUV, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Ferroelectric polarization tailored spin polarized electronic structure and magnetic anisotropy in two-dimensional ScSi2N4/CuInP2S6 multiferroic heterostructures
Authors: Zhao Zhenxian , Wang Xiaocha , Mi Wenbo
Published: September 2023

Two-dimensional (2D) van der Waals (vdW) multiferroic heterostructures which consist of vdW intrinsic magnets and ferroelectrics (FEs) plays an extremely important role in novel 2D spintronic devices. In this paper, the electronic structure and magnetic anisotropy of 2D vdW ScSi2N4/CuInP2S6 heterostructure are systematically investigated using first-principles calculation. CuInP2S6 is a 2D FE material with out-of-plane polarization, and ScSi2N4 is a half-metal with ferromagnetic (FM) properties. After the ab initio molecular dynamics simulations, the structures of upward polarization (P↑) and downward polarization (P↓) states are stable. Both the P↑ and P↓ states of ScSi2N4/CuInP2S6 heterostructure are FM half-metals. Biaxial strains modulate the electronic structure and magnetic properties of the ScSi2N4/CuInP2S6 heterostructure. With the application of compressive strains in P↓ state, the spin-up band crosses Fermi level and the P↓ state changes from half-metal to metal. The transition from half-metal to metal in P↑ state is realized at ϵ = −4% and ϵ = −6%. The magnetic anisotropy energy of the P↓ state can be enhanced by compressive strains of −2% and −4%. The P↓ state shows the largest average planar electrostatic potential of 0.819 eV at ϵ = −6%, which keeps the maximum electrostatic field between ScSi2N4 and CuInP2S6 monolayers. As the strain increases from −2% to −6%, the potential difference of P↑ state increases gradually. At +6% tensile strain, the band structure inversion occurred in both P↑ and P↓ states. These results demonstrate the potential of 2D vdW multiferroic heterostructures and can enrich the field of spintronic devices.
Evaluation of three approaches used for respiratory measurement in healthy subjects
Authors: Duan Xiaojuan , Song Xin , Yang Caidie , Li Yunchi , Wei Liang , Gong Yushun , Li Yongqin
Published: September 2023

Objective. Respiration is one of the critical vital signs of human health status, and accurate respiratory monitoring has important clinical significance. There is substantial evidence that alterations in key respiratory parameters can be used to determine a patient’s health status, aid in the selection of appropriate treatments, predict potentially serious clinical events and control respiratory activity. Although various approaches have been developed for respiration monitoring, no definitive conclusions have been drawn regarding the accuracy of these approaches because each has different advantages and limitations. In the present study, we evaluated the performance of three non-invasive respiratory measurement approaches, including transthoracic impedance (IMP), surface diaphragm electromyography-derived respiration (EMGDR) and electrocardiogram-derived respiration (ECGDR), and compared them with the direct measurement of airflow (FLW) in 33 male and 38 female healthy subjects in the resting state. Approach. The accuracy of six key respiratory parameters, including onset of inspiration (Ion
), onset of expiration (Eon
), inspiratory time (It
), expiratory time (Et
), respiratory rate (RR) and inspiratory–expiratory ratio (I:E), measured from the IMP, EMGDR and ECGDR, were compared with those annotated from the reference FLW. Main results. The correlation coefficients between the estimated inspiratory volume and reference value were 0.72 ± 0.20 for IMP, 0.62 ± 0.23 for EMGDR and 0.46 ± 0.21 for ECGDR (p < 0.01 among groups). The positive predictive value and sensitivity for respiration detection were 100% and 100%, respectively, for IMP, which were significantly higher than those of the EMGDR (97.2% and 95.5%, p < 0.001) and the ECGDR (96.9% and 90.0%, p < 0.001). Additionally, the mean error (ME) for Ion
, Eon
, It
, Et
and RR detection were markedly lower for IMP than for EMGDR and ECGDR (p < 0.001). Significance. Compared with EMGDR and ECGDR, the IMP signal had a higher positive predictive value, higher sensitivity and lower ME for respiratory parameter detection. This suggests that IMP is more suitable for dedicated respiratory monitoring and parameter evaluation.
Evanescent coupling of nonlinear integrated cavities for all-optical reservoir computing
Authors: Boikov I K , Brunner D , De Rossi A
Published: September 2023

We consider theoretically a network of evanescently coupled optical microcavities to implement a space-multiplexed optical neural network in an integrated nanophotonic circuit. Nonlinear photonic network integrations based on evanescent coupling ensure a highly dense integration, reducing the chip footprint by several orders of magnitude compared to commonly used designs based on long waveguide connections while allowing the processing of optical signals with bandwidth in a practical range. Different nonlinear effects inherent to such microcavities are studied for realizing an all-optical autonomous computing substrate based on the reservoir computing concept, and their contribution to computing performance is demonstrated. We provide an in-depth analysis of the impact of basic microcavity parameters on the computational metrics of the system, namely, the dimensionality and the consistency. Importantly, we find that differences between frequencies and bandwidths of supermodes formed by the evanescent coupling are the determining factor of the reservoir’s dimensionality and scalability. The network’s dimensionality can be improved with frequency-shifting nonlinear effects such as the Kerr effect, while two-photon absorption has the opposite effect. Finally, we demonstrate in simulation that the proposed reservoir is capable of solving the Mackey–Glass prediction and the optical signal recovery tasks at gigahertz timescale.
Temperature-dependent dielectric properties of p-n heterojunction diodes based on hydrothermally synthesized ZnO nanostructures
Authors: Çağırtekin Ali Orkun , Ajjaq Ahmad , Barin Özlem , Acar Selim
Published: September 2023

In this study, the effect of coating p-Si substrates with a pure ZnO layer using the hydrothermal reaction method on the dielectric parameters was reported. The studied dielectric properties of the ZnO/p-Si structure include dielectric constant (ε′), dielectric loss (ε″), ac electrical conductivity (σ
AC), and real and imaginary electrical modulus (M′, M″). These properties were investigated using experimental capacitance-frequency (C-f) and conductivity-frequency (G-f) measurements in a frequency range of 20 Hz-1 MHz and a temperature range of 300-420 K. Experimental results show that dielectric parameters are strongly frequency- and temperature-dependent. The dielectric constant showed an increase of about 11 times in the investigated temperature range. At the same time, AC electrical conductivity increased with increasing frequency and temperature. In addition, the electrical modulus was examined, and peaks were observed in M″ values. It was observed that the peaks shifted to the high-frequency region with the increase in temperature. The activation energies were also calculated from the conductivity parameters and a decrease was observed in the activation energies as the frequency increased. Regardless of temperature and frequency, the higher dielectric loss of the fabricated diode compared to its dielectric constant can be advantageous for certain heating or electromagnetic absorption applications.
Pulse electromagnetic flow of Jeffrey fluid in parallel plate microchannels
Authors: Li Dongsheng , Li Kun , Li Haibin
Published: September 2023

This paper investigates the pulse electromagnetic flow of a Jeffery fluid between parallel plate microchannels, where the pulse is considered as a relatively stable and common rectangular pulse. The Laplace transform and residue theorem are employed to derive the analytical solutions for the velocity and volumetric flow rate of the pulse electromagnetic flow. Graphical representations depict the effects of several important parameters, including the Hartmann number

H
a
,

pulse width

a
¯

,

relaxation time

λ
¯

1

and retardation time

λ
¯

2

on them. The study findings demonstrate that the Hartmann number

H
a

plays a vital role in the investigation of pulse electromagnetic flow. During the first half-cycle of the pulse electric field, the magnitude of the velocity amplitude increases and then decreases with the Hartmann number

H
a
.

An interesting observation is that in the second half-cycle, larger Hartmann number

H
a

values result in a decrease in velocity followed by a reverse increase. The profiles of velocity and volumetric flow rate exhibit oscillations over a relatively short period of time, then gradually reach a stable state with time and display periodic variation characteristics. Moreover, a larger pulse width

a
¯

leads to a longer variation period and more stable profiles of velocity and volumetric flow rate. For smaller Hartmann numbers

H
a
,

the magnitude of the volumetric flow rate amplitude grows with the relaxation time

λ
¯

1

and reduces with the retardation time

λ
¯

2

.

However, as the Hartmann number

H
a

increases, the influence of relaxation time

λ
¯

1

and retardation time

λ
¯

2

on the volumetric flow rate becomes significantly weakened, especially the retardation time

λ
¯

2

.
Graphene metamaterial-based broadband/dual-narrowband switchable terahertz absorber with adjustable absorptivity and large phase shift
Authors: Ma Xiaoya , Jiang Mingzhu , Song Zihang , Hu Fangrong , Zhang Longhui , Li Yanke , Han Jiaguang
Published: September 2023

We present a graphene metamaterial-based broadband/dual-narrowband switchable terahertz (THz) absorber with adjustable absorptivity and large phase shift. From top to bottom of the device, there are graphene-metal hybrid pattern, silicon dioxide layer, silicon layer and metal substrate. When the Fermi energy (EF) of graphene is equal to 0 eV, it has two narrowband absorption peaks at frequencies of 1.88 THz and 2.54 THz, respectively. However, when the EF is equal to 0.8 eV, it turns to a broadband absorber in the frequency range from 1.60 to 2.42 THz. Moreover, if the EF increases from 0.2 eV to 0.8 eV, its absorptivity can be dynamically adjusted from 60% to more than 90% in a broadband of 0.82 THz. Most importantly, the absorber can also dynamically control the phase shift. In the frequency range of 2.04 THz to 2.34 THz, a maximum dynamic phase shift of 192 degrees is achieved by changing the EF of graphene. This work provides an alternative method for constructing multifunctional integrated THz devices based on graphene metamaterial.
Local discrimination of lattice states via complete graph
Authors: Liu Qian-Qian , Yang Ying-Hui , Chen Pei-Ying , Wang Xiao-Li
Published: September 2023

In this paper, we use graph theory to study the distinguishability of lattice states under local operations and classical communication (LOCC) in

C

p

2

⨂

C

p

2

. Firstly, we present that for the basis of lattice unitary matrices, there are (p
2 + 1)(p + 1) distinct maximal commuting sets in p
2-dimensional system. Secondly, for any set



of lattice states, we can obtain a graph G which consists of some k-complete subgraphs. Using the graph G, we show that the set



can be distinguished by one-way LOCC if

n
(
p
+
1
)
−

∑

k
=
1

p
+
1

s

k

(
k
−
1
)
<
(

p

2

+
1
)
(
p
+
1
)

, where n is the number of vertices of a graph G and s

k
is the number of k-complete subgraphs. Moreover, we also proved that this conclusion is necessary and sufficient in

C

2

2

⨂

C

2

2

. For

C

p

2

⨂

C

p

2

system, our result can cover the results in (2015, Phys. Rev. A
92, 042 320); (2020, Sci. China-Phys. Mech. Astron.
63, 280 312).
New method to revisit the gravitational lensing analysis of the Bullet Cluster using radio waves
Authors: Yoon Youngsub , Park Jong-Chul , Hwang Ho Seong
Published: September 2023

Gravitational lensing studies of the Bullet Cluster suggested convincingly in favor of the existence of dark matter.
However, it was performed without the knowledge of the original orientation of each galaxy before gravitational lensing.
A potential improvement to this issue lies in the measurement of the original orientation from the polarization direction of radio waves emitted from each galaxy.
In this context, Francfort et al. derived a formula that can utilize the information about the original orientation of each galaxy to obtain what is called shear.
However, we demonstrate that shear in their formula should be replaced by reduced shear when the change in sizes of images of galaxies is taken into account.
As the previous gravitational lensing analysis of the Bullet Cluster used reduced shear, we suggest applying our improved formula directly for the reanalysis once we obtain the polarization direction of radio waves.
In particular, we show that our new formula can yield a more accurate analysis than the previous one, if the polarization direction can be measured more precisely than 10°.
Moreover, the approach discussed in this work is generically applicable to the gravitational lensing analysis of clusters, not only limited to the Bullet Cluster.
Study on the Effect of Anti-galloping Device with Cubic Stiffness and Particle Damping
Authors: Zhao Bin , Cheng Yongfeng , Wang Jingchao , Liu Bin , Chen Yushu
Published: September 2023

The galloping of iced conductors is a common disaster of overhead conductors. Most traditional anti-galloping devices lack a nonlinear dynamic vibration absorber; hence, they have a limited anti-galloping effect. In this study, we designed, optimized, and tested an electric power fitting and an anti-galloping device with cubic stiffness and particle damping for ultra-high-voltage (UHV) transmission lines. We built a nonlinear dynamic model of the coupling galloping system comprising split conductors and anti-galloping devices. The harmonic balance method obtained the steady-state analytical solutions and corresponding averaged equations. The test spans in the laboratory were used to design the test program and equipment. We verified the accuracy of the nonlinear dynamic model and the harvesting effect of the anti-galloping device with cubic stiffness and particle damping. The theoretical and experimental results were highly consistent, and in the range of (0, 2] Hz, the anti-galloping device reduced the galloping amplitude. Therefore, cubic stiffness and particle damping can effectively improve the anti-galloping ability of UHV transmission lines, prolonging their service period.
Study on Heat Transfer Performance of Flat Plate Pulsating Heat Pipe with Graphene Oxide at Low Heating Power
Authors: Shi Yang , Su Lei
Published: September 2023

Graphene oxide (GO) has high thermal conductivity and strong hydrophilicity which can enhance the heat transfer performance of the fluid. Standby heat transfer is a long-time, low-heat power and small heat area heat transfer, caused in electronic equipment. In this paper, the heat transfer performance of flat plate pulsating heat pipe (FPPHP) under the different concentrations of GO as working fluid is studied to solve the standby heat transfer and analyze the enhancement and the retardation of the GO to FPPHP. The FPPHP is made of aluminum, 2 tubes, with the concentration of GO, is 0.1%, 0.3%, 0.5%, a heating power range of 1∼10 W, and a filling rate (FR) is 30%. The results of the experiment indicate that under the condition of the concentration of 30% of GO, the FPPHP startup at 4 W and run stably at 6 W. When the heating power is 10 W, the wall temperature of evaporation is 89.75 °C, the thermal resistance is 1.18 °C/W.
Advanced exergy analysis of a novel air source heat pump system coupled with the liquid receiver and gas-liquid separator
Authors: Zhu Chao , Ma Longxia , Wang Fenghao , Wang Zhihua , Li Yongpeng , Liu Zixuan , Shi Peng , Ding Tao
Published: September 2023

In previous studies, an air source heat pump system coupled with the liquid receiver and the gas-liquid separator was proposed, which improved the defrosting efficiency according to the improvement of the refrigerant mass flow during defrosting and shortened the defrosting time. In this paper, the exergy efficiencies and exergy loss (including endogenous and exogenous exergy loss) of the new system are studied. They are compared with the original air source heat pump system by constructing the advanced exergy study model of the system. Results show that the exergy efficiencies of the compressor, evaporator, and throttle valve of the new system are increased by 0.2%, 2.3%, and 5.9%, respectively. The endogenous exergy loss of the new system accounts for 65.16% of the total exergy loss of the system, and most of the exergy loss in the new system is caused by the components themselves.