bluuebunny/crossref_metadata_2025 huggingface dataset:
Self-similarity in cubic blocks of R-operators
Authors: Korepanov Igor G.
Published: October 2023

Cubic blocks are studied assembled from linear operators R acting in the tensor product of d linear “spin” spaces. Such operator is associated with a linear transformation A in a vector space over a field F of a finite characteristic p, like “permutation-type” operators studied by Hietarinta [J. Phys. A: Math. Gen. 30, 4757–4771 (1997)]. One small difference is that we do not require A and, consequently, R to be invertible; more importantly, no relations on R are required of the type of Yang–Baxter or its higher analogues. It is shown that, in d = 3 dimensions, a pn × pn × pn block decomposes into the tensor product of operators similar to the initial R. One generalization of this involves commutative algebras over F and allows to obtain, in particular, results about spin configurations determined by a four-dimensional R. Another generalization deals with introducing Boltzmann weights for spin configurations; it turns out that there exists a non-trivial self-similarity involving Boltzmann weights as well.
Development of a compact impact two-degree-of-freedom linear-rotary piezoelectric motor using one piezoelectric actuator
Authors: Han Liling , Xu Zhenying , Zhang Yanhu , Wang Yun
Published: October 2023

A compact impact two-degree-of-freedom linear-rotary piezoelectric motor is proposed using a single actuator. The proposed piezoelectric actuator has a pair of deformation counteracting helical interdigitated electrodes on its outside surface, which can be divided into two parts. When the two parts of the piezoelectric actuator are driving under the same driving voltage signals, the motor can realize independent linear motion. When the two parts of the piezoelectric actuator are driving under the driving voltage signals with opposite duty cycles, the motor can realize independent rotary motion. The fabricated piezoelectric motor can produce a maximum average linear velocity of 1.9 and −2.3 mm/s with a saw-shaped driving signal of 400 Vp-p (peak-to-peak driving voltage) at 9 kHz. Experiments also show that the fabricated piezoelectric motor can realize a maximum average rotary velocity of 2440 and −2235 mrad/s with a driving signal of 400 Vp-p at 9 kHz. The maximum load force and torque of the prototype are about 0.4 N and 1.5 mN m, respectively. The proposed motor provides a wide driving frequency and realizes high velocity in both linear and rotary motions.
A hard mask process and alignment device aims to achieve high consistency and mass-scale production of gas sensors based on spraying hydrothermal gas sensing material
Authors: Tang YanKun , Lai Penghui , Hu Zongxin , Luo Yu , Wang Hairong , Yu Lingmin
Published: October 2023

The material synthesized through the hydrothermal method has received extensive and in-depth study in recent years, with a large number of literature reporting their excellent performance in the fields of catalysis or gas sensitivity. In order to combine the hydrothermal material with micro-electro-mechanical system processes to achieve large-scale manufacturing of hydrothermal synthesized materials at the wafer-level, this paper proposes a series of processes for hard mask patterned electro-atomization spraying of hydrothermal materials and designs and manufactures an alignment device that achieves the alignment of silicon hard mask and electrode wafers based on the vacuum clamping principle. Through experiments, it has been verified that this device can achieve micrometer-level alignment between the hard mask and the electrode wafer. By conducting electro-atomization spraying, hard mask patterning, optical microscopy, and confocal laser scanning microscope measurements, as well as gas sensitivity testing on a CeO2/TiO2 hydrothermal composite material published in our previous research, it was further verified that this process has good film formation consistency (Sa and Sq are both less than 3 μm and the average film thickness deviation is less than 5 μm), excellent and consistent gas sensitivity performance, and good long-term working stability. This article provides a promising process method for the large-scale production of hydrothermal synthesis materials at the wafer-level.
Electron-to-nuclear spectral mapping via dynamic nuclear polarization
Authors: Pillai Arjun , Elanchezhian Moniish , Virtanen Teemu , Conti Sophie , Ajoy Ashok
Published: October 2023

We report on a strategy to indirectly read out the spectrum of an electronic spin via polarization transfer to nuclear spins in its local environment. The nuclear spins are far more abundant and have longer lifetimes, allowing for repeated polarization accumulation in them. Subsequent nuclear interrogation can reveal information about the electronic spectral density of states. We experimentally demonstrate the method by reading out the ESR spectrum of nitrogen vacancy center electrons in diamond via readout of lattice 13C nuclei. Spin-lock control on the 13C nuclei yields a significantly enhanced signal-to-noise ratio for the nuclear readout. Spectrally mapped readout presents operational advantages in being background-free and immune to crystal orientation and optical scattering. We harness these advantages to demonstrate applications in underwater magnetometry. The physical basis for the “one-to-many” spectral map is itself intriguing. To uncover its origin, we develop a theoretical model that maps the system dynamics, involving traversal of a cascaded structure of Landau–Zener anti-crossings, to the operation of a tilted “Galton board.” This work points to new opportunities for “ESR-via-NMR” in dilute electronic systems and in hybrid electron–nuclear quantum memories and sensors.
Delta-alpha cross-frequency coupling for different brain regions
Authors: Lukarski Dushko , Petkoski Spase , Ji Peng , Stankovski Tomislav
Published: October 2023

Neural interactions occur on different levels and scales. It is of particular importance to understand how they are distributed among different neuroanatomical and physiological relevant brain regions. We investigated neural cross-frequency couplings between different brain regions according to the Desikan–Killiany brain parcellation. The adaptive dynamic Bayesian inference method was applied to EEG measurements of healthy resting subjects in order to reconstruct the coupling functions. It was found that even after averaging over all subjects, the mean coupling function showed a characteristic waveform, confirming the direct influence of the delta-phase on the alpha-phase dynamics in certain brain regions and that the shape of the coupling function changes for different regions. While the averaged coupling function within a region was of similar form, the region-averaged coupling function was averaged out, which implies that there is a common dependence within separate regions across the subjects. It was also found that for certain regions the influence of delta on alpha oscillations is more pronounced and that oscillations that influence other are more evenly distributed across brain regions than the influenced oscillations. When presenting the information on brain lobes, it was shown that the influence of delta emanating from the brain as a whole is greatest on the alpha oscillations of the cingulate frontal lobe, and at the same time the influence of delta from the cingulate parietal brain lobe is greatest on the alpha oscillations of the whole brain.
Insights into the structure and Ion transport of pectin-[BMIM][PF6] electrolytes
Authors: Mohapatra Sipra , Halder Sougata , Chaudhari Sachin R. , Netz Roland R. , Mogurampelly Santosh
Published: October 2023

We investigate the effect of pectin on the structure and ion transport properties of the room-temperature ionic liquid electrolyte 1-n-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) using molecular dynamics simulations. We find that pectin induces intriguing structural changes in the electrolyte that disrupt large ionic aggregates and promote the formation of smaller ionic clusters, which is a promising finding for ionic conductivity. Due to pectin in [BMIM][PF6] electrolytes, the diffusion coefficient of cations and anions is observed to decrease by a factor of four for a loading of 25 wt. % of pectin in [BMIM][PF6] electrolyte. A strong correlation between the ionic diffusivities (D) and ion-pair relaxation timescales (τc) is observed such that D ∼ τc−0.75 for cations and D ∼ τc−0.82 for anions. The relaxation timescale exponents indicate that the ion transport mechanisms in pectin-[BMIM][PF6] electrolytes are slightly distinct from those found in neat [BMIM][PF6] electrolytes (D∼τc−1). Since pectin marginally affects ionic diffusivities at the gain of smaller ionic aggregates and viscosity, our results suggest that pectin-ionic liquid electrolytes offer improved properties for battery applications, including ionic conductivity, mechanical stability, and biodegradability.
Effect of chamber pressure on the output characteristics of a low-pressure DC plasma torch
Authors: Krushna Mohanta Ram , Kumawat Devilal , Ravi G
Published: October 2023

This study explores the effects of chamber pressure on the electrical and thermodynamic characteristics of a low-pressure thermal plasma jet. The investigation focuses on current–voltage characteristics, arc voltage fluctuations, plasma jet temperature, electron density, and velocity within the range of 100–500 A arc current, at chamber pressures of 100 Pa, 1 kPa, and 3 kPa. Spectral analysis of the arc voltage reveals the presence of distinct frequencies, including restrike, Helmholtz, and acoustic modes, which exhibit varying behavior under different chamber pressure conditions. Restrike frequency shows an increase with decreasing chamber pressure, while Helmholtz frequency remains unaffected, and the power density of the acoustic frequency diminishes, eventually disappearing from the spectrum. The transition of the plasma jet from a continuum regime to a frozen state with decreasing chamber pressure is observed along with its shock structures. Optical emission spectroscopy is utilized to map the excitation temperature and electron density profile along the jet axis, demonstrating that the jet temperature and density peaks at the compression zone. Furthermore, Mach probe measurements of the plasma jet velocity at different axial locations, under various chamber pressure conditions, illustrate that the plasma jet maintains a supersonic state, regardless of chamber pressure. However, after the formation of a Mach disk, the jet velocity becomes subsonic. The highest velocity is achieved at 100 Pa chamber pressure, reaching Mach 2.9 at 50 mm from the anode exit. This research enhances our understanding of thermal plasma jets under low-pressure conditions, contributing to the advancement of knowledge in their applications across various domains.
Measurement and optimization of the beam coupling impedance of a novel 3D-printed titanium alloy cage inside the thin-wall vacuum chamber
Authors: Du Shaohui , Liu Jie , Zhu Guangyu , Yang Jiancheng , Jiao Jiqiang , Zhang Xiang , Shen Guodong , Wu Junxia , Luo Cheng , Meng Jun
Published: October 2023

Dipole magnet vacuum chambers are among the most critical and costly components of rapid-cycling accelerator facilities. Alternative approaches to traditional ceramic chambers have been explored for the implementation of fast-ramping dipole-magnet vacuum chambers, including thin-wall metallic beam pipe chambers strengthened with transverse ribs and ceramic rings inside thin-walled chambers. Here, we report a novel 3D-printed titanium alloy cage inside the thin-wall vacuum chamber, which is designed for high-intensity heavy ion accelerator facility (HIAF) to reduce manufacturing difficulty and cost, shorten the production cycle, and improve the quality. Comprehensive studies were undertaken to characterize the impedance of the 3D-printed titanium alloy cage inside the thin-wall vacuum chamber. The beam-coupling impedance and eddy currents of the new thin-wall vacuum chamber were studied mostly numerically. Strategies for further reducing the beam-coupling impedance were explored. In addition, impedance bench measurements using the “half wavelength” resonant method were conducted to identify the longitudinal and transverse impedances of the 3D-printed titanium alloy cage inside the thin-wall vacuum chamber prototype experimentally. The simulated and measured results for the impedance were consistent. Furthermore, a campaign for resonance-check measurements on the 3D-printed titanium alloy ring loaded inside a thin-wall vacuum chamber prototype was launched. This novel thin-wall vacuum chamber structure is now entering the fabrication stage and will soon be ready for installation in the Booster Ring (BRing).
Design, modeling and simulation of nuclear-powered integrated energy systems with cascaded heating applications
Authors: Poudel Bikash , Gautam Mukesh , Li Binghui , Huang Jianqiao , Zhang Jie
Published: October 2023

Nuclear-renewable integrated energy systems (IES) consist of a variety of energy generation and conversion technologies and can be used to meet heterogeneous end uses (e.g., electricity, heat, and cooling demands). In addition to supply-demand balance, end-use heat demands usually require heat supply of certain temperature ranges. The effective and efficient utilization of heat produced within an IES is, therefore, a critical challenge. This paper examines design options of an IES that includes heating processes of multiple temperature grades. We investigate a cascaded design configuration, where the remaining residual heat after high-grade heating processes [e.g., hydrogen production through high-temperature steam electrolysis (HTSE)] is recovered to meet the low-grade heating needs [e.g., district heating (DH)]. Additionally, a thermal energy storage system is integrated into the DH system to address the imbalance between heat supply and demand. This paper primarily focuses on the design and modeling of the proposed system and evaluates its operation with a 24-h transient process simulation using a DH demand profile with hourly resolution. The results indicate that the residual heat from the HTSE exhaust is insufficient for the DH demand, and additional topping heat directly from the reactor process steam is needed. Furthermore, the inclusion of thermal energy storage within the DH system provides the necessary balance between thermal generation and demand, thereby ensuring a consistent rated temperature of the DH supply water. This approach helps minimize the control actions needed on the reactor side.
Pulse-periodic gas discharge in atmospheric pressure helium with nanosecond excitation fronts
Authors: Bokhan P. A. , Gugin P. P. , Lavrukhin M. A. , Zakrevsky D. E. , Schweigert I. V.
Published: October 2023

The characteristics of barrier gas discharge in helium at atmospheric pressure are investigated when excited by pulses with voltage rise fronts of 3–10 ns and a pulse repetition rate of 5–100 kHz. The volumetric mode of the pulse current up to 80 A with a peak power of up to 1.5 MW and a specific power supply of an average power of up to 250 W cm−3 is realized. An increase in the steepness of the excitation pulses has little effect on the discharge current value but allows to maintain the volumetric nature of the current flow to the higher operating voltages. It is demonstrated that the maximum discharge current is restricted by an increase in ionization with an increase in the electron current from the cathode due to the ion–electron emission and charging of the dielectric surface, which increases the floating potential of the cathode surface relative to plasma.
Nonlocal phase coupling in turbulence spreading across the magnetic island
Authors: Zhang Y. , Jiang M. , Guo Z. B. , Xu Y. , Mao Z. J. , Hu Z. Q. , Xu J. Q. , Ke R. , Long T. , Wen J. , Yu X. , Li J. Q. , Xu M. ,   HL-2A Team
Published: October 2023

We study the nonlocal phase coupling during turbulence spreading across the magnetic island. It is found that the coherent convective cells (sharing similar features to quasi-coherent mode in experiment) on both sides of the O-point boundary are accumulated during the island formation. The phase entrainment of the convective cells on the turbulence both in the inner and the outer regions of the magnetic island sets up a nonlocal phase coupling channel and leads to a fast spreading of the outer turbulence into the magnetic island by conquering the flow shear at the O-point boundary. This nonlocal coupling mechanism of turbulence spreading is analogous to a turbulence version of the well-known enhanced diffusion of passive scalars in laminar convective flows of neutral fluid system.
Conformal bilayer h-AlN epitaxy on WS2 by ALD with ultralow leakage current
Authors: Wang Shin-Yuan , Chang Shu-Jui , Huang Yu-Che , Chih Jia Hao , Lin Yu-Chin , Cheng Chao-Ching , Radu Iuliana , Hu Chenming , Chien Chao-Hsin
Published: October 2023

In this work, we develop an ultrathin epitaxial h-AlN as an interfacial layer (IL) between HfO2 and monolayer WS2 channel by atomic layer deposition (ALD). The growth of ultrathin dielectrics using ALD has been challenging due to the dangling-bond-free surface of 2D materials. By utilizing sub-1 nm h-AlN as an IL and depositing HfO2 high-k dielectric, we were able to form a uniform and atomically flat gate dielectric without voids. The resulting structure exhibits an equivalent oxide thickness as low as 1 nm and ultra-low leakage currents of ∼10−6 A/cm2. The fabricated top-gate WS2 transistors demonstrate on-off ratios of around 106 and subthreshold swing as low as 93 mV/dec. Furthermore, we have verified the feasibility of using h-AlN IL for a gate-all-around structure. Our work presents a CMOS-compatible low-temperature ALD process for integrating gate dielectrics, offering excellent thickness scalability and uniform coverage around monolayer WS2 nanosheets. The combination of high-quality two-dimensional dielectrics and semiconductors will contribute to the development of future high-performance and low-power electronic devices.
Exploring plasmonic effect on exciton transport: A theoretical insight from macroscopic quantum electrodynamics
Authors: Weng Shih-Han , Hsu Liang-Yan , Ding Wendu
Published: October 2023

Exciton transport in extended molecular systems and how to manipulate such transport in a complex environment are essential to many energy and optical-related applications. We investigate the mechanism of plasmon-coupled exciton transport by using the Pauli master equation approach, combined with kinetic rates derived from macroscopic quantum electrodynamics. Through our theoretical framework, we demonstrate that the presence of a silver nanorod induces significant frequency dependence in the ability of transporting exciton through a molecule chain, indicated by the exciton diffusion coefficient, due to the dispersive nature of the silver dielectric response. Compared with the same system in vacuum, great enhancement (up to a factor of 103) in the diffusion coefficient can be achieved by coupling the resonance energy transfer process to localized surface plasmon polariton modes of the nanorod. Furthermore, our analysis reveals that the diffusion coefficients with the nearest-neighbor coupling approximation are ∼10 times smaller than the results obtained beyond this approximation, emphasizing the significance of long-range coupling in exciton transport influenced by plasmonic nanostructures. This study not only paves the way for exploring practical approaches to study plasmon-coupled exciton transport but also provides crucial insights for the design of innovative plasmon-assisted photovoltaic applications.
Amide isomerization pathways: Electronic and structural background of protonation- and deprotonation-mediated cis-trans interconversions
Authors: Kelemen Ádám A. , Perczel András , Horváth Dániel , Jákli Imre
Published: October 2023

The cis-trans isomerization of amide bonds leads to wide range of structural and functional changes in proteins and can easily be the rate-limiting step in folding. The trans isomer is thermodynamically more stable than the cis, nevertheless the cis form can play a role in biopolymers’ function. The molecular system of N-methylacetamide · 2H2O is complex enough to reveal energetics of the cis-trans isomerization at coupled cluster single-double and coupled cluster single–double and perturbative triple [CCSD(T)] levels of theory. The cis-trans isomerization cannot be oversimplified by a rotation along ω, since this rotation is coupled with the N-atom pyramidal inversion, requesting the introduction of a second dihedral angle “α.” Full f(ω,α) potential energy surfaces of the different amide protonation states, critical points and isomerization reaction paths were determined, and the barriers of the neutral, O-protonated and N-deprotonated amides were found too high to allow cis-trans interconversion at room temperature: ∼85, ∼140, and ∼110 kJ mol−1, respectively. For the N-protonated amide bond, the cis form (ω = 0°) is a maximum rather than a minimum, and each ω state is accessible for less than ∼10 kJ mol−1. Here we outline a cis-trans isomerization pathway with a previously undescribed low energy transition state, which suggests that the proton is transferred from the more favorable O- to the N-protonation site with the aid of nearby water molecules, allowing the trans → cis transition to occur at an energy cost of ≤11.6 kJ mol−1. Our results help to explain why isomerase enzymes operate via protonated amide bonds and how N-protonation of the peptide bond occurs via O-protonation.
Numerical study on optimization of secondary air box in a 600 MW opposed wall-fired boiler
Authors: Ning Xinyu , Yue Yang , Huang Jian , Ding Haoxuan , Li Bin , Deng Lei , Li Yiguo
Published: October 2023

The opposed wall-fired boiler has been widely employed in power plants in China due to its adaptability. However, the airflow in the same layer burners from the large air box is uneven, affecting the combustion characteristics of pulverized coal and causing the corrosion and slagging of the water-cooled wall. In this study, the numerical simulation is performed on a 600 MW wall-fired boiler to investigate the air distribution and flow characteristics of each burner and the secondary air duct under variable boiler loads (100%, 75%, 50%, and 30%), which would provide the basis for optimization of the secondary air box. The effectiveness of the modified burner, over-fire air (OFA) nozzle, and secondary air duct is demonstrated through the numerical simulation. The results indicate that the burner and OFA nozzle exhibit distinct flow deviation characteristics within the original air box. Specifically, the burner demonstrates a flow deviation ranging from 2% to 4%, whereas the OFA nozzle exhibits a flow deviation ranging from 10% to 35%. Integrating poly air rings into the burners and OFA nozzles on the sidewall separately addresses the issue of non-uniform flow distribution of the OFA nozzle while concurrently improving the air flow rate on both sides of the burners and OFA nozzles. The main air duct could be divided into three smaller air ducts by installing two deflectors at the corner of the secondary air duct. This scheme effectively decreases the pressure drops at the corner interface from 337.4 to 254.3 Pa. The findings of this study could have the potential to offer scientific insights into and recommendations for the optimal functioning of the boiler system.
Nonequilibrium interfacial properties of chemically driven fluids
Authors: Cho Yongick , Jacobs William M.
Published: October 2023

Chemically driven fluids can demix to form condensed droplets that exhibit phase behaviors not observed at equilibrium. In particular, nonequilibrium interfacial properties can emerge when the chemical reactions are driven differentially between the interior and exterior of the phase-separated droplets. Here, we use a minimal model to study changes in the interfacial tension between coexisting phases away from equilibrium. Simulations of both droplet nucleation and interface roughness indicate that the nonequilibrium interfacial tension can either be increased or decreased relative to its equilibrium value, depending on whether the driven chemical reactions are accelerated or decelerated within the droplets. Finally, we show that these observations can be understood using a predictive theory based on an effective thermodynamic equilibrium.
Effect of horizontal aspect ratio on convection rolls in the presence of transverse magnetic field
Authors: Sharma Lekha , Pal Pinaki
Published: October 2023

We perform three-dimensional direct numerical simulations to investigate the effect of transverse magnetic field on the convection rolls of electrically conducting fluids using the classical Rayleigh–Bénard convection model. The control parameters “Q” (the Chandrasekhar number), “r” (the reduced Rayleigh number), and “Γ” (horizontal aspect ratio) are varied in the ranges 0≤Q≤2000, 1≤r≤25, and 1/2≤Γ≤2, respectively, for two different Prandtl numbers (Pr=0.025 and 0.1). In the absence of the magnetic field, the system allows convection in the form of two dimensional rolls near the onset, and it is suppressed by the Lorentz force appearing in the presence of transverse magnetic field. As a result, primary instability is moved toward higher r for Q>0, and the movement increases with Γ. Interestingly, for weak to moderate magnetic fields, there exists two different kinds of onset depending on Γ and Q. Steady oblique rolls (SOR) and transverse rolls (STR) are preferred at the onset accordingly as Γ<1 and Γ>1, respectively, while for Γ = 1, both STR and SOR are found to occur at the onset depending on Q. On the other hand, stronger transverse magnetic field orients the flow toward itself for Γ≥1. In the considered parameter regime, diverse routes to chaos including period-doubling, quasiperiodic, intermittent, and transient are observed close to the onset along with some interesting scaling laws associated with the oscillatory instability of the rolls.
PCSK9 activation promotes early atherosclerosis in a vascular microphysiological system
Authors: Lee Jounghyun H. , Shores Kevin L. , Breithaupt Jason J. , Lee Caleb S. , Fodera Daniella M. , Kwon Jennifer B. , Ettyreddy Adarsh R. , Myers Kristin M. , Evison Benny J. , Suchowerska Alexandra K. , Gersbach Charles A. , Leong Kam W. , Truskey George A.
Published: October 2023

Atherosclerosis is a primary precursor of cardiovascular disease (CVD), the leading cause of death worldwide. While proprotein convertase subtilisin/kexin 9 (PCSK9) contributes to CVD by degrading low-density lipoprotein receptors (LDLR) and altering lipid metabolism, PCSK9 also influences vascular inflammation, further promoting atherosclerosis. Here, we utilized a vascular microphysiological system to test the effect of PCSK9 activation or repression on the initiation of atherosclerosis and to screen the efficacy of a small molecule PCSK9 inhibitor. We have generated PCSK9 over-expressed (P+) or repressed (P−) human induced pluripotent stem cells (iPSCs) and further differentiated them to smooth muscle cells (viSMCs) or endothelial cells (viECs). Tissue-engineered blood vessels (TEBVs) made from P+ viSMCs and viECs resulted in increased monocyte adhesion compared to the wild type (WT) or P− equivalents when treated with enzyme-modified LDL (eLDL) and TNF-α. We also found significant viEC dysfunction, such as increased secretion of VCAM-1, TNF-α, and IL-6, in P+ viECs treated with eLDL and TNF-α. A small molecule compound, NYX-1492, that was originally designed to block PCSK9 binding with the LDLR was tested in TEBVs to determine its effect on lowering PCSK9-induced inflammation. The compound reduced monocyte adhesion in P+ TEBVs with evidence of lowering secretion of VCAM-1 and TNF-α. These results suggest that PCSK9 inhibition may decrease vascular inflammation in addition to lowering plasma LDL levels, enhancing its anti-atherosclerotic effects, particularly in patients with elevated chronic inflammation.
Enhancing spin–orbit torques with a low voltage in metallic multi-layered heterostructures
Authors: He Zhexi , Zhao Yifan , Zhao Shishun , Li Yaojin , Liu Jiaqiang , Zha Xi , Zhao Meng , Du Yujing , Wang Rui , Jiang Yuxuan , Zhou Ziyao , Liu Ming
Published: October 2023

The manipulation of spin–orbit torque (SOT) manifests enormous potentiality in the field of spintronics due to virtues of low power consumption, ultrafast spin-flips, and high-density integration. Increaser the spin hall angle of the spin source layer or the SOT efficiency are the key approaches of achieving low power spintronics. Here, we report an enhancement of spin–orbit torques in Ta/Co/Pt heterostructures using low-voltage ionic liquid gating. The effective spin Hall angle increased threefold with an applied voltage of 2 V. As expected, the enhanced spin Hall angle lowers the critical current density by 66.7% (1.14 × 107 to 3.80 × 106 A cm−2). By the lock-in harmonic Hall voltage measurements, the outstanding performance of manipulation of the spin–orbit coupling originates from the electrostatic doping interracially by the ionic liquid. In addition to the significant fundamentals, our work could be feasibly wielded toward the spintronics such as memory and logic devices in the behaviors of energy-efficient and impressive tunability.
Ratiometric luminescent thermometry for the third bioimaging window by Er3+ doped garnet with large Stark splitting
Authors: Liu Shuaiqi , Ueda Jumpei , Tanabe Setsuhisa
Published: October 2023

Based on the 4I13/2 → 4I15/2 emission (1450–1700 nm) of Er3+ in garnet, which is matching well with third bioimaging window (NIR-III), we propose a ratiometric near-infrared (NIR) thermometer (YAGG:Ce-Er) in NIR-III by utilizing thermal coupling between Stark levels of 4I13/2, where energy levels were split into seven sublevels (I–VII). The energy gaps between Stark sublevel VII and I (ΔEVII-I) and V and I (ΔEV-I) of the 4I13/2 level, calculated from the temperature dependence of intensity ratios of the two selected thermal couples, corresponded well with the theoretical values. This agreement supports the analysis that the system can be utilized as a Boltzmann thermometry. Moreover, the relative sensitivity (Sr) within the temperature range commonly encountered in organisms (25–60 °C) reached a value of 0.63 ± 0.03% K−1 for the VII/I ratio and 0.57 ± 0.07% K−1 for the V/I ratio. These high relative sensitivity values indicate the strong potential for practical application in various biological fields.
Experimental demonstration of a dual-input/dual-output reflective impedance metasurface
Authors: Keyrouz Jean Louis , Ataloglou Vasileios G. , Eleftheriades George V.
Published: October 2023

This paper presents the experimental demonstration of a dual-input/dual-output reflective impedance metasurface. The design of the metasurface relies on the Method of Moments and leverages auxiliary surface waves to achieve anomalous reflection of two impinging plane waves with controlled sidelobe levels. The two beams are chosen independently compared to those in a conventional phase-gradient metasurface where the design presents a single slope to achieve a certain reflection and all other incident beams would depend on that slope. A prototype that ensures maximum directivity at two prescribed reflection angles for the two input waves is then fabricated on a Rogers RO3003 printed-circuit board using 42 metawires loaded with printed capacitors. The proposed metasurface is capable of reflecting an incident beam from −20° to −55° and a second from +10° to 50° at 9.93 GHz. The metasurface is experimentally characterized and an illumination efficiency of at least 89% is calculated for each of the reflected waves, indicating a high multiplexing efficacy.
Weakly nonlinear instability analysis of triple diffusive convection under internal heat generator and modulated boundaries
Authors: Jakhar Atul , Kumar Anand , Gupta Vinod K.
Published: October 2023

A nonlinear instability analysis of triple diffusive convection under the time-dependent heat and mass transfer boundary conditions in the presence of internal heat source is evaluated in this study. On various physical parameters, the momentary behavior of both Sherwood and Nusselt number profiles is examined. In the geometry, we have considered two parallel infinite horizontal plates acting gravity vertically downward z-direction. By using the weakly nonlinear analysis, the Ginzburg–Landau equation is generated for the rate of heat and mass transport. Here, we have considered the temperature and concentration of two solutes. The temperature and first concentration of the solute at the lower plate are higher than the upper plate, while the second concentration of the solute at the upper plate is higher compared to that of the lower plate. According to the different modulation, we have considered four cases based on the phase angle of the modulations. The convective heat and mass transports are measured as a function of the Nusselt number (Nu) and Sherwood number (Sh1 and Sh2) for both the concentration. From the results, it is found that the first Lewis number increases all the considered profiles, while Ri increases the Nusselt number profile only. The principal discovery elucidated by this article resides in the observation that the internal heat source, subject to modulated boundaries, maintains the convective instability if different solutes are used from both ends.
Quantum oscillations and nontrivial topological properties of layered metal SrAg4Sb2
Authors: Nie Yong , Tu Wenqian , Yang Yang , Chen Zheng , Wang Yuanyuan , Pan Senyang , Mei Ming , Zhu Xiangde , Lu Wenjian , Ning Wei , Tian Mingliang
Published: October 2023

We investigate on the synthesis and physical properties of layered metal SrAg4Sb2 single crystals. The crystals present large unsaturated magnetoresistance up to 2.4 × 104% at T = 1.8 K and B = 28 T. Strong quantum oscillations were observed in both magnetotransport and magnetic torque measurements under high magnetic fields. The analysis of oscillations reveals the existence of multi-bands in this material. Our experimental results and the theoretical calculation suggest that SrAg4Sb2 hosts a nontrivial topological bandgap and should be a topological semimetal candidate.
Hypersonic flow and heat transfer of a micro-rough plate in the near-continuum regime
Authors: Guo Jinghui , Wang Xiaoyong , Li Sijia , Lin Guiping
Published: October 2023

Hypersonic near-continuum flow over a flat plate with micro-scale roughness is studied using the kinetic direct simulation Monte Carlo method on roughness module configurations with different relative roughness (h) values and roughness densities (RN) under a matrix of freestream parameters (Mach number Ma∞, Reynolds number Re∞, temperature T∞, and Knudsen number Kn∞). An open-source Stochastic PArallel Rarefied-gas Time-accurate Analyzer code, which enables Cartesian grid adaption and efficient parallelization, is utilized for the rough-plate flow simulations. Flowfield analysis reveals that the local patterns inside the roughness modules evolve starting from closed (two vortices) via transitional ultimately to open (one vortex) by an increase in h, with co-existing shrinkage of high-density zones and attenuation of density peaks. The surface quantities are significantly influenced by the flowfield characteristics, and a local association between the peak heat flux and the peak pressure is identified. Non-dimensional peak heating and pressure correlation laws for the local peak heat flux and pressure coefficients in terms of two length-scale transformations are proposed, enabling the capture of local heating and pressure extrema on rough plates with varying h and RN conditions under different Ma∞, Re∞, and T∞ parameter values. The peak heat flux and pressure coefficients can be described by analogous correlating equations expressed by first-order-polynomial or power functions. An increase in the rarefaction degree (Kn∞) deviating from the near-continuum regime causes the correlation laws to fail.
Cryogenic packaging of nanophotonic devices with a low coupling loss <1 dB
Authors: Zeng Beibei , De-Eknamkul Chawina , Assumpcao Daniel , Renaud Dylan , Wang Zhuoxian , Riedel Daniel , Ha Jeonghoon , Robens Carsten , Levonian David , Lukin Mikhail , Riedinger Ralf , Bhaskar Mihir , Sukachev Denis , Loncar Marko , Machielse Bart
Published: October 2023

Robust, low-loss photonic packaging of on-chip nanophotonic circuits is a key enabling technology for the deployment of integrated photonics in a variety of classical and quantum technologies including optical communications and quantum communications, sensing, and transduction. To date, no process has been established that enables permanent, broadband, and cryogenically compatible coupling with sub-dB losses from optical fibers to nanophotonic circuits. Here, we report a technique for reproducibly generating a permanently packaged interface between a tapered optical fiber and nanophotonic devices on diamond with a record-low coupling loss <1 dB per facet at near-infrared wavelengths (∼730 nm) that remains stable from 300 K to 30 mK. We further demonstrate the compatibility of this technique with etched lithium niobate on insulator waveguides. The technique lifts performance limitations imposed by scattering as light transfers between photonic devices and optical fibers, paving the way for scalable integration of photonic technologies at both room and cryogenic temperatures.
Non-Hermitian control of localization in mosaic photonic lattices
Authors: Longhi Stefano
Published: October 2023

Exploring the deep insight into localization, disorder, and wave transport in non-Hermitian systems is an emergent area of research of relevance in different areas of physics. Engineered photonic lattices, with spatial regions of optical gain and loss, provide a prime and simple physical platform for tailoring non-Hermitian Hamiltonians and for unveiling the intriguing interplay between disorder and non-Hermiticity. Here, it is shown that in mosaic photonic lattices with on-site uncorrelated disorder or quasi-periodic order, the addition of uniform loss at alternating sites of the lattice results in the suppression or enhancement of wave spreading, thus providing a simple method for non-Hermitian control of wave transport in disordered systems. The results are illustrated by considering discrete-time quantum walks in synthetic photonic lattices.
Low-cost, interdigitated capacitive sensor using laser-written graphene foam for touch, proximity, and liquid level detection
Authors: Devinder Shital , Joseph Shereena , Pandey Saurabh , Joseph Joby
Published: October 2023

Flexible capacitive sensors are gaining popularity in place of sophisticated optical sensing or bulky mechanical designs for specific applications such as proximity/gesture detection and liquid level sensing. So, here, we propose Laser Induced Graphene Foam (LIGF) based planar capacitive sensors, which are flexible, highly sensitive, energy-efficient, and cost-effective, making them accessible for various applications. The working of these sensors involves the interdigitated planar electrode configuration and the fringing effect, influencing capacitance when the permittivity or the electric charge of the surrounding medium changes. LIGF planar capacitive elements were produced on a commercially availed polymer polyimide by using direct laser writing technique employing a low-cost diode laser. The developed LIGF-based planar capacitive touch sensor showed an average touch response (|ΔC/Co|) of more than 49%; moreover, when used for proximity sensing, this sensor could detect the presence of human hand up to a maximum distance of 170 mm from the sensor surface. An extended design of the sensor has demonstrated liquid level sensing with an accuracy of 0.97 mm. As a result of its ability to sense dielectric materials, contactless operation, long-range sensing, cost-effectiveness, low-power consumption, and environmental friendliness, the LIGF electrode-based capacitive sensor can be incorporated into a variety of modern technology and devices.
Deterioration of mild anxiety and depression with Better Access treatment: implications for scaling up psychotherapy worldwide
Authors: Allison Stephen , Bastiampillai Tarun , Kisely Steve , Looi Jeffrey C. L.
Published: October 2023

The Australian Medicare Better Access initiative in mental health reached one in every 10 Australians in 2021 (more than 2.6 million people) with interventions targeted at mild-to-moderate anxiety and depression, provided by general practitioners, allied health professionals, and/or psychiatrists, at a cost of AUD1.2 billion. However, the overall mental health of the Australian population has not improved since the introduction of Better Access. The benefits of population-scale mental health interventions (medications and psychotherapies) might have been overestimated for milder conditions, and the iatrogenic potential underestimated. A recent evaluation of Better Access found that mild anxiety and depressive symptoms were threefold more likely to worsen (32%) rather than improve (10%). Better Access might be targeted more cost-effectively towards severe and complex conditions, for which treatment appears to have superior risk–benefit ratios. These findings have implications for similar initiatives worldwide, such as those proposed by the World Health Organization.
The macroeconomic spillovers from space activity
Authors: Corrado Luisa , Grassi Stefano , Paolillo Aldo , Silgado-Gómez Edgar
Published: October 2023

The resurgence in space activities we are witnessing may provide opportunities for new technologies to generate potential spillovers to the real economy. To address this view, we propose a macroeconomic model with endogenous growth and a space sector. The model describes the relationship between space investment and technological spillovers, which support persistent economic growth. Our estimates indicate that space activities provide growth spillovers that peak from the late 1960s to the early 1980s. Recent space activities have a much lower economic impact. Finally, extensive experiments quantify the economic relevance of our results.
Oligopoly competition between satellite constellations will reduce economic welfare from orbit use
Authors: Guyot Julien , Rao Akhil , Rouillon Sébastien
Published: October 2023

Orbital space enables many essential services, such as weather forecasting, global communication, navigation, Earth observation for environmental and agricultural management, and national security applications. Orbit use is increasingly defined by firms launching coordinated fleets—“constellations”—of satellites into low-Earth orbit. These firms operate in markets with few or no competitors, such as the market for broadband internet provision to rural areas. How will oligopolistic competition shape the allocation of orbital space? We analyze orbital-use patterns and economic welfare when two profit-maximizing firms operate satellite constellations with sophisticated collision avoidance systems. We compare this duopoly equilibrium to public utility constellations designed and regulated to maximize economic welfare from orbit use. We show that imperfect competition reduces economic welfare from orbit use by up to 12%—$1.1 billion USD—per year and distorts the allocation of orbital space. The nature of the distortion depends on the magnitude of constellation-related environmental damages. When damages are low, economic welfare is maximized by larger-than-equilibrium constellations. When damages are high, economic welfare is maximized by smaller-than-equilibrium constellations. Between the growing commercial and national interests in outer space and the importance of low-Earth orbit to space exploration, orbit-use management is likely to be a fruitful and policy-relevant area for economic research. We conclude with a discussion of future research directions in orbit-use management relevant to policymakers around the world.
Perceptual learning across saccades: Feature but not location specific
Authors: Grzeczkowski Lukasz , Shi Zhuanghua , Rolfs Martin , Deubel Heiner
Published: October 2023

Perceptual learning is the ability to enhance perception through practice. The hallmark of perceptual learning is its specificity for the trained location and stimulus features, such as orientation. For example, training in discriminating a grating’s orientation improves performance only at the trained location but not in other untrained locations. Perceptual learning has mostly been studied using stimuli presented briefly while observers maintained gaze at one location. However, in everyday life, stimuli are actively explored through eye movements, which results in successive projections of the same stimulus at different retinal locations. Here, we studied perceptual learning of orientation discrimination across saccades. Observers were trained to saccade to a peripheral grating and to discriminate its orientation change that occurred during the saccade. The results showed that training led to transsaccadic perceptual learning (TPL) and performance improvements which did not generalize to an untrained orientation. Remarkably, however, for the trained orientation, we found a complete transfer of TPL to the untrained location in the opposite hemifield suggesting high flexibility of reference frame encoding in TPL. Three control experiments in which participants were trained without saccades did not show such transfer, confirming that the location transfer was contingent upon eye movements. Moreover, performance at the trained location, but not at the untrained location, was also improved in an untrained fixation task. Our results suggest that TPL has both, a location-specific component that occurs before the eye movement and a saccade-related component that involves location generalization.
GAS41 promotes H2A.Z deposition through recognition of the N terminus of histone H3 by the YEATS domain
Authors: Kikuchi Masaki , Takase Shohei , Konuma Tsuyoshi , Noritsugu Kota , Sekine Saaya , Ikegami Takahisa , Ito Akihiro , Umehara Takashi
Published: October 2023

Glioma amplified sequence 41 (GAS41), which has the Yaf9, ENL, AF9, Taf14, and Sas5 (YEATS) domain that recognizes lysine acetylation (Kac), regulates gene expression as a subunit of the SRCAP (SNF2-related CREBBP activator protein) complex that deposits histone H2A.Z at promoters in eukaryotes. The YEATS domains of the proteins AF9 and ENL recognize Kac by hydrogen bonding the aromatic cage to arginine situated just before K9ac or K27ac in the N-terminal tail of histone H3. Curiously, the YEATS domain of GAS41 binds most preferentially to the sequence that contains K14ac of H3 (H3K14ac) but lacks the corresponding arginine. Here, we biochemically and structurally elucidated the molecular mechanism by which GAS41 recognizes H3K14ac. First, stable binding of the GAS41 YEATS domain to H3K14ac required the N terminus of H3 (H3NT). Second, we revealed a pocket in the GAS41 YEATS domain responsible for the H3NT binding by crystallographic and NMR analyses. This pocket is away from the aromatic cage that recognizes Kac and is unique to GAS41 among the YEATS family. Finally, we showed that E109 of GAS41, a residue essential for the formation of the H3NT-binding pocket, was crucial for chromatin occupancy of H2A.Z and GAS41 at H2A.Z-enriched promoter regions. These data suggest that binding of GAS41 to H3NT via its YEATS domain is essential for its intracellular function.