bluuebunny/crossref_metadata_2025 huggingface dataset:
Force of droplet impact on thin liquid films
Authors: Yu Xiaolong , Shao Yifan , Teh Kwee-Yan , Hung David L. S.
Published: April 2022

Inertia-dominated droplet impact transfers momentum to a dry flat target within a short span of time t characterized by (droplet diameter D)/(impact speed U). We investigate experimentally how impact force dynamics change when a droplet hits a thin liquid film of thickness H, less than or approximately equal to the droplet diameter, atop the flat target. Impact force and morphology are recorded simultaneously by piezoelectric force sensing and high-speed video imaging. Compared with a dry surface, the force of droplet impact on a thin liquid film is found to follow the same initial tU/D scaling and reach a slightly higher peak value, but at a significantly later time. Modeling the impact process as a perfect inelastic collision between the droplet and a liquid column of height equal to the film thickness yields the proper timescale (H+D)/U to characterize temporal evolution of the impact force near the inertial peak and through its subsequent exponential decay. The impact crater penetration depth developing within the thin film over the same time span is also found to collapse to a self-similar form based on this characteristic timescale, which attests to the validity of the inelastic collision model in capturing the underlying impact flow physics.
All carbon p-n border in bilayer graphene by the molecular orientation of intercalated corannulene
Authors: Maruyama Mina , Okada Susumu
Published: April 2022

Geometric and electronic structures of a corannulene (C20H10) intercalated bilayer graphene are investigated in terms of the molecular conformation using density functional theory. Our calculations indicate that the electronic structure of bilayer graphene is tunable by controlling the molecular conformation of corannulene. Holes and electrons coexist on the upper and lower layers of graphene, which are situated at the convex region and edge of corannulene when it has the bowl conformation. In contrast, bilayer graphene has a tiny gap of 4.7 meV at the K point owing to the substantial interaction between graphene and corannulene when corannulene has flat conformation. Electron and hole redistribution in bilayer graphene intercalating corannulene indicated the possibility of all carbon p-n border at an interface between corannulene with convex and concave arrangements. The intercalation substantially decreases the energy difference between the ground state bowl conformation and the metastable state flat conformation by approximately 400 meV. Accordingly, the two-dimensional nano-spacing between the graphene layers changes the molecular conformation of corannulene from a bowl to a flat structure at 139 MPa.
Stochastic behavior of an interface-based memristive device
Authors: Yarragolla Sahitya , Hemke Torben , Trieschmann Jan , Zahari Finn , Kohlstedt Hermann , Mussenbrock Thomas
Published: April 2022

A large number of simulation models have been proposed over the years to mimic the electrical behavior of memristive devices. The models are based either on sophisticated mathematical formulations that do not account for physical and chemical processes responsible for the actual switching dynamics or on multi-physical spatially resolved approaches that include the inherent stochastic behavior of real-world memristive devices but are computationally very expensive. In contrast to the available models, we present a computationally inexpensive and robust spatially 1D model for simulating interface-type memristive devices. The model efficiently incorporates the stochastic behavior observed in experiments and can be easily transferred to circuit simulation frameworks. The ion transport, responsible for the resistive switching behavior, is modeled using the kinetic cloud-in-a-cell scheme. The calculated current–voltage characteristics obtained using the proposed model show excellent agreement with the experimental findings.
Flat phonon modes driven ultralow thermal conductivities in Sr3AlSb3 and Ba3AlSb3 Zintl compounds
Authors: Yang Zhaoyu , Min Jingjing , Dong Tieshuan , Wen Weiru , Feng Zhenzhen , Yang Gui , Yan Yuli , Zeng Zaiping
Published: April 2022

Searching for compounds with intrinsic low lattice thermal conductivity has been proven a successful strategy for achieving high thermoelectric performance. Herein, employing density functional theory calculations combined with electron and phonon Boltzmann transport theories, we report that Sr3AlSb3 and Ba3AlSb3 within the Zintl 3–1–3 compositional family exhibit record low thermal conductivities of 0.78 and 0.55 W/mK at room temperature, respectively. These low thermal conductivities are rooted in low-energy optical phonon modes with strong anharmonicity and the emergence of high-energy flat optical phonon modes with zero contribution to the lattice thermal conductivity. Heavier cationic atoms are found to soften low-lying optical phonon modes, which enhance phonon scattering and, therefore, favor a lower thermal conductivity. These combined characteristics lead to high and balanced figure of merit values around 2.3 for Zintl Ba3AlSb3 at both optimal p-type and n-type doping and high temperature. Our work highlights the important role of flat optical phonon modes on designing promising thermoelectric materials with intrinsic low thermal conductivity.
Nighttime electric power generation at a density of 50 mW/m2 via radiative cooling of a photovoltaic cell
Authors: Assawaworrarit Sid , Omair Zunaid , Fan Shanhui
Published: April 2022

A large fraction of the world's population lacks access to the electric grid. Standard photovoltaic (PV) cells can provide a renewable off-grid source of electricity but only produce power from daytime solar irradiance and do not produce power at night. While there have been several theoretical proposals and experimental demonstrations of energy harvesting from the radiative cooling of a PV cell at night, the achieved power density is very low. Here, we construct a device, which incorporates a thermoelectric generator that harvests electricity from the temperature difference between the PV cell and the ambient surrounding. We achieve 50 mW/m2 nighttime power generation with a clear night sky, with an open-circuit voltage of 100 mV, which is orders of magnitude higher as compared with previous demonstrations. During the daytime, the thermoelectric generator also provides additional power on top of the electric power generated directly from the PV cells. Our system can be used as a continuous renewable power source for both day- and nighttime in off-grid locations.
Optimal efficiency of focusing diffused light through scattering media with iterative wavefront shaping
Authors: Woo Chi Man , Zhao Qi , Zhong Tianting , Li Huanhao , Yu Zhipeng , Lai Puxiang
Published: April 2022

Iterative wavefront shaping is a powerful tool to overcome optical scattering and enable the focusing of diffusive light, which has exciting potential in many applications that desire localized light delivery at depths in tissue-like complex media. Unsatisfactory performance and efficiency, however, have been a long-standing problem, and the large discrepancy between theoretical and experimental results has hindered the wide applications of the technology. Currently, most algorithms guiding the iterative search for optimum phase compensation rely heavily on randomness to achieve solution diversity. It is similar to black-box optimization, in which the mechanism for arriving at a good solution is unclear. The lack of clear guidance on the new solution generation process considerably affects the efficiency of optimization. Therefore, we propose a probability-based iterative algorithm that combines the genetic algorithm and ant colony optimization to develop new solutions based on a probability map. Thanks to the clearer guidance provided by the probability map and the reduced involvement of randomness, we can obtain optimization results with optimal efficiency for single and multiple focuses behind scattering media. In addition, with the proposed algorithm, we also demonstrate higher adaptability in an unstable scattering environment and more spatially uniform optical focusing in the field of view. This study advances the state-of-the-art in the practice of iterative wavefront shaping. More importantly, the significant improvement in optimization efficiency and adaptability, if further engineered, can potentially inspire or open up wide applications that desire localized and enhanced optical delivery in situ.
Transport modes of inertial particles and their effects on flow structures and heat transfer in Rayleigh–Bénard convection
Authors: Yang Wenwu , Wang Bo-Fu , Tang Shuai , Zhou Quan , Dong Yuhong
Published: April 2022

We investigate the flow characteristics and kinetic behaviors of particles in turbulent Rayleigh–Bénard convection particulate flows. Direct numerical simulations combined with a Lagrangian point-particle strategy were carried out in the range of Stokes numbers 2×10−4≤StL≤7.3×10−2 for Rayleigh numbers from 2×106 to 108 at the Prandtl number Pr=0.678. A two-way coupling model is employed in which the momentum exchange between the dispersed particles and the carrier fluid is taken fully into account. Based on various patterns of particle motion, we find three transport modes of inertial particles which are labeled as the circling transport (CCT) mode, the channel transport (CNT) mode, and the downpour transport (DPT) mode, respectively. These modes can switch to each other when Stokes numbers and Rayleigh numbers vary and exhibit different effects of particle motions on the flow field and heat transfer. For the CCT and DPT modes, compared with the CNT, a weakening alteration of flow structures and thermal plumes leads to no significant effect on the transport of momentum and heat. For the CNT mode, a pronounced effect of particles on enhancements of the turbulent momentum transport and heat transfer relates to the strong interaction between the particle clusters and the chaotic structures of eddies. What is more, the particles tend to homogeneously distribute for the CCT and DPT modes, although the particles exhibit different transport states. As for the CNT mode, under both preferential sweeping and centrifugal effects, particles accumulate into clusters that hover toward the region of high strain rate and the edges of eddies. We found that the averaged particle settling speeds are almost proportional to the Stokes number. The particle settling speeds are larger than the terminal velocity of Stokesian particles for the CCT and CNT modes as particles tend to settle in the downward fluid. In contrast, it becomes smaller than the terminal velocity for the DPT mode due to the drag of the upward fluid.
Interplay of self-assembly and viscoelasticity in chiral liquid crystal gels
Authors: Khan Raj Kumar , Majumdar Sayantan , Ramarao Pratibha
Published: April 2022

Electro-optic and photonic devices that are robust against external stresses and deformation offer several technological advantages. A variety of device applications based on chiral liquid crystals (LCs) exhibiting blue phases (BPs), chiral nematic (N*), and ferroelectric Smectic (SmC*) phases have already been demonstrated. Chiral LC-gels are, therefore, among the best soft materials that can further extend device performance and functionality by combining electro-optic and photonic properties with mechanical stability. In view of this, a composite material composed of two highly chiral calamitic LCs and a low-molecular-weight organogelator was developed and investigated using a variety of experimental techniques. Optical microscopy, selective reflection, and x-ray diffraction studies show that the LC characteristics are very well retained in the chiral LC-gels, namely, BPIII-gel, BPII-gel, BPI-gel, N*-gel, twist grain boundary A phase (TGBA)-gel, and SmC*-gel, which form sequentially as the sample is gradually cooled from the isotropic phase. Rheological studies establish that the chiral LC-gels exhibit several features of a soft viscoelastic solid. This has been understood in terms of the mode of self-assembly of the gelator fibers and the ubiquitous defects pertinent to different LC phases. The major highlights of the study are the formation of a defect-mediated strong N*-gel with enhanced viscoelastic moduli and the induction of a TGBA-gel. The stretchable nature of a free-standing film of the BPI-gel that retains its shape over time is another interesting aspect of the present work.
A wettability pattern-mediated trapped bubble removal from a horizontal liquid–liquid interface
Authors: Chowdhury Imdad Uddin , Mahapatra Pallab Sinha , Sen Ashis Kumar
Published: April 2022

The passage of a bubble through an immiscible horizontal liquid–liquid interface has a wide range of applications, from chemical processes to microfluidic devices. Buoyancy governs this passage of the bubble, and at the liquid–liquid interface, the bubble encounters a downward pulling force due to surface tension. Depending on the volume of the bubble, it may pass through or become trapped at the interface. In this study, for the first time, we proposed the idea of trapped bubble removal from a liquid–liquid interface with the aid of a wettability-patterned cone. The bubble detachment dynamic is investigated using numerical results and theoretical analysis. The effect of fluid properties and cone parameters on bubble detachment has been extensively studied. It is found that density contrast (ρr) and viscosity contrast (μr) of both the liquids, surface tension ratio (σr), bubble diameter (d0), wettability of the cone (θ), and cone angle (α) play a crucial role in bubble detachment. Here, we studied the effect of each parameter on the bubble detachment and, based on that, identified two distinct regimes, e.g., detached regime and non-detached regime. The regime map is represented by two non-dimensional groups βco and ψ, which are functions of Bond number (Bo), Ohnesorge number (Oh), α, and θ. Furthermore, the transport characteristics of the bubble on the cone after the detachment indicate that the bubble velocity decreased as it moved from the narrower to the wider section of the cone. These findings could be useful in the removal of trapped bubbles from a liquid–liquid interface in small-scale chemical industries.
The effect of body position while coughing on the airborne transmission of pathogens
Authors: Amjadimanesh Hossein , Norouzi Mohammad , Johnson Matthew S. , Sadrizadeh Sasan , Abouali Omid
Published: April 2022

Given the recent acceptance of the central role of airborne transmission for SARS-CoV-2, increased attention has been paid to the dispersion of respiratory droplets in different scenarios. Studies including numerical simulations have been conducted on methods for breaking the chains of transmission. Here, we present the first such study on the impact of body position while coughing on the dispersion of respiratory droplets. Four scenarios are examined, including normal standing, bending the head at different angles, coughing into the elbow in still air, and a gentle breeze from the front and behind. The model showed that an uncovered cough is dangerous and causes many droplets to enter the environment, posing a cross-contamination threat to the others. Droplets with an initial diameter smaller than 62.5 μm remain suspended in windless air for more than 3 min. In the presence of wind, these droplets move with the wind flow and may travel long distances greater than 3.5 m. The model showed that covering the mouth with the elbow while coughing is clearly the best strategy for reducing airborne transmission of exhaled pathogens. About 62% of the initial number of droplets deposit on the cougher's elbow immediately after the cough and have no chance of spreading through the air in both windless and windy conditions. Covering the cough in windless or light breeze conditions also causes the upward thermal plume around the body to expel many small droplets.
Electron transfer and spin–orbit coupling: Can nuclear motion lead to spin selective rates?
Authors: Chandran Suraj S. , Wu Yanze , Teh Hung-Hsuan , Waldeck David H. , Subotnik Joseph E.
Published: April 2022

We investigate a spin-boson inspired model of electron transfer, where the diabatic coupling is given by a position-dependent phase, eiWx. We consider both equilibrium and nonequilibrium initial conditions. We show that, for this model, all equilibrium results are completely invariant to the sign of W (to infinite order). However, the nonequilibrium results do depend on the sign of W, suggesting that photo-induced electron transfer dynamics with spin–orbit coupling can exhibit electronic spin polarization (at least for some time).
Ordering kinetics of a tapered copolymer based on isoprene and styrene
Authors: Galanos Eftyxis , Steube Marvin , Butt Hans-Juergen , Frey Holger , Floudas George
Published: April 2022

High molar mass copolymers with a tapered interface are mechanically tough materials with an accessible order-to-disorder transition temperature and hence processability. We report the first ordering kinetics for a tapered tetrablock copolymer in comparison to a conventional diblock copolymer made sequentially. We show that tapered copolymers belong to the Brazovskii “universality class,” where fluctuations play a dominant role. Consequently, the order-to-disorder transition has a very weak, fluctuation-induced first-order character. The ordering kinetics of the lamellar phase from the supercooled disordered melt revealed several distinct differences associated with the range of metastability (increased), the timescales (bimodal), and the exact mechanism of ordering. The results are discussed in terms of the reduced interaction parameter and the introduction of structural defects within the lamellar grains.
Generalization of the Tavis–Cummings model for multi-level anharmonic systems: Insights on the second excitation manifold
Authors: Campos-Gonzalez-Angulo Jorge A. , Yuen-Zhou Joel
Published: April 2022

Confined electromagnetic modes strongly couple to collective excitations in ensembles of quantum emitters, producing light–matter hybrid states known as polaritons. Under such conditions, the discrete multilevel spectrum of molecular systems offers an appealing playground for exploring multiphoton processes. This work contrasts predictions from the Tavis–Cummings model in which the material is a collection of two-level systems, with the implications of considering additional energy levels with harmonic and anharmonic structures. We discuss the exact eigenspectrum, up to the second excitation manifold, of an arbitrary number N of oscillators collectively coupled to a single cavity mode in the rotating-wave approximation. Elaborating on our group-theoretic approach [New J. Phys. 23, 063081 (2021)], we simplify the brute-force diagonalization of N2 × N2 Hamiltonians to the eigendecomposition of, at most, 4 × 4 matrices for arbitrary N. We thoroughly discuss the eigenstates and the consequences of weak and strong anharmonicities. Furthermore, we find resonant conditions between bipolaritons and anharmonic transitions where two-photon absorption can be enhanced. Finally, we conclude that energy shifts in the polaritonic states induced by anharmonicities become negligible for large N. Thus, calculations with a single or few quantum emitters qualitatively fail to represent the nonlinear optical response of the collective strong coupling regime. Our work highlights the rich physics of multilevel anharmonic systems coupled to cavities absent in standard models of quantum optics. We also provide concise tabulated expressions for eigenfrequencies and transition amplitudes, which should serve as a reference for future spectroscopic studies of molecular polaritons.
Efficiency assessment of a single surface dielectric barrier discharge plasma actuator with an optimized Suzen–Huang model
Authors: Sujar-Garrido P. , Becerra M. , Örlü R.
Published: April 2022

Spatial and time-resolved characteristics of a single surface dielectric barrier discharge (sDBD) actuator are experimentally and numerically investigated. The paper also focuses on the efficiency of sDBD actuators used as flow-control devices. The motivation is the need for developing a cost-effective way to optimize the balance between control performance and actuator power consumption. The study considers the steady state as often employed in experiments as well as the transient regime. Experimental methods to obtain the active power are revisited, and for the first time, the commonly used simplified phenomenological Suzen–Huang model (SHM) is used for the computation of electrical characteristics. The SHM represents fair qualitative features of the starting vortex. However, it fails when time-resolved velocity profiles are compared. Results show that even with an optimized parametrical analysis of the “tuned” plasma variables, the model is not able to fully reproduce the induced wall-jet neither spatially nor temporally. Furthermore, it underestimates the power consumption by more than 80%. The intrinsic challenge of accurately measuring the alternating current of the DBD and the instantaneous mechanical power, together with the failure of representing time-resolved velocity profiles and the underestimated electric power by the model, highlights that a better phenomenological model including gas dynamics and electric characteristics or using a fully coupled physical plasma model is required.
Tackling an accurate description of molecular reactivity with double-hybrid density functionals
Authors: Brémond Éric , Li Hanwei , Pérez-Jiménez Ángel José , Sancho-García Juan Carlos , Adamo Carlo
Published: April 2022

In this Communication, we assess a panel of 18 double-hybrid density functionals for the modeling of the thermochemical and kinetic properties of an extended dataset of 449 organic chemistry reactions belonging to the BH9 database. We show that most of DHs provide a statistically robust performance to model barrier height and reaction energies in reaching the “chemical accuracy.” In particular, we show that nonempirical DHs, such as PBE0-DH and PBE-QIDH, or minimally parameterized alternatives, such as ωB2PLYP and B2K-PLYP, succeed to accurately model both properties in a balanced fashion. We demonstrate, however, that parameterized approaches, such as ωB97X-2 or DSD-like DHs, are more biased to only one of both properties.
Study of the secondary droplet breakup mechanism and regime map of Newtonian and power law fluids at high liquid–gas density ratio
Authors: Kant Krishna , Banerjee R.
Published: April 2022

This work reports the numerical investigation of the secondary breakup of non-Newtonian droplets at different Weber Weg and Ohnesorge Ohl numbers. As part of this work, an in-house coupled level set volume of fluid solver is developed based on OpenFOAM libraries. It uses improved curvature calculation techniques like smoothening and the closest point search method. Flow is assumed to be axisymmetric. Approximately 95 different cases were simulated to investigate the effect of Weg and Ohl numbers on secondary breakup for Newtonian, shear-thinning, and shear-thickening fluids. Ohl varies from 10−3 to 101, and, correspondingly, Weg varies from 101 to 103. The non-Newtonian rheology is modeled as a power-law fluid, and the power-law index n ranged from 0.2–1.8. The present work describes the flow field near the droplet and the effects of non-Newtonian parameters and viscosity on the flow field. The various aspects of droplet dynamics like droplet deformation ratio y, deformation rate ẏ, and coefficient of pressure Cp are studied and compared with the internal flow theory. A generalized relation for critical Weber number Weg,cr is proposed for both Newtonian and non-Newtonian fluids and is shown in a phase diagram plot to map the different regimes of secondary droplet breakup.
Improvement of 650-nm red-emitting GaIn0.17N/GaIn0.38N multiple quantum wells on ScAlMgO4 (0001) substrate by suppressing impurity diffusion/penetration
Authors: Takahashi Ryo , Fujiki Ryoto , Hozo Keisuke , Hiramatsu Ryoya , Matsukura Makoto , Kojima Takahiro , Han Dong-Pyo , Iwaya Motoaki , Takeuchi Tetsuya , Kamiyama Satoshi
Published: April 2022

This study aims to improve the crystalline quality of 650-nm GaIn0.17N/GaIn0.38N red-emitting multiple quantum wells (MQWs) fabricated on a ScAlMgO4 (SCAM) substrate. When using the SCAM substrate, the diffusion and/or penetration of impurities, including Mg, Sc, O, and Al, from the SCAM substrate poses as a challenge. To address this issue, we introduced an Al0.74In0.26N layer between the SCAM substrate and MQWs, which was lattice-matched to the substrate. The Al0.74In0.26N layer effectively blocked the diffusion of impurities from the SCAM substrate into the adjacent layers during the metal-organic vapor epitaxy (MOVPE) growth. For further suppression, a thick AlN layer was deposited on the back of the SCAM substrate before the MOVPE growth, which effectively suppressed impurity penetration from the growth surface. The structure proposed in this study improved the crystallinity and the surface roughness of MQWs, resulting in the improvement of internal quantum efficiency by approximately three times compared to that of the conventional sample.
Empty liquid state and re-entrant phase behavior of the patchy colloids confined in porous media
Authors: Hvozd T. V. , Kalyuzhnyi Yu. V. , Vlachy V. , Cummings P. T.
Published: April 2022

Patchy colloids with three and four equivalent patches, confined in an attractive random porous medium, undergo re-entrant gas–liquid phase separation with the liquid phase density approaching zero at low temperatures. The (bonding) colloid–colloid interaction causes the liquid–gas phase separation, which is modulated by the presence of the randomly distributed hard-sphere obstacles, attracting the colloids via Yukawa potential. Due to this interaction, a layer of mutually bonded colloids around the obstacles is formed. The network becomes nonuniform, with colloid particles locally centered on the obstacles. Features described in this article may open possibilities to produce equilibrium gels with predefined nonuniform distribution of particles and indicate how complicated the phase behavior of biological macromolecules in a crowded environment may be.
Ganglia dynamics during imbibition and drainage processes in nanoporous systems
Authors: Zhang Tao , Zhang Liehui , Zhao Yulong , Zhang Ruihan , Zhang Dongxu , He Xiao , Ge Feng , Wu Jianfa , Javadpour Farzam
Published: April 2022

We study the gas–water transient imbibition and drainage processes in two-dimensional nanoporous media using our recently developed lattice Boltzmann model. To describe the microscopic molecular interactions, the model employs a pseudopotential that correlates the local density and interaction strength to perform simulation at a mesoscopic scale. The primary interest is ganglia dynamics in the nanoporous media affected by fluid and geometrical properties of the porous structure. We performed sensitivity analyses on the fluid and rock characteristics such as the Euler number, gas–water interfacial area, water film area, capillary pressure, pore size distribution, specific surface area, and wettability. The simulation results revealed the fingering nature of the nonwetting phase. In the imbibition process, the flow pathway of water results in isolated and trapped gas bubble clusters because of the strong attraction between water and solid surfaces. In the drainage process, the pressure difference between the gas phase and the water phase depends on both the capillary pressure and the disjoining pressure due to the presence of water film. Pore topography and specific surface area control the continuity of the fluid phases in the imbibition process. In nonwet systems, the water phase starts fingering in the nanoporous system. The present work elucidates the microscopic ganglia dynamics of gas–water two-phase flow in nanoporous media. The microscopic scale details will help establish the macroscopic flow equation to accurately predict two-phase flow in shale gas, tight oil, and caprock seals.
CryoCiM: Cryogenic compute-in-memory based on the quantum anomalous Hall effect
Authors: Alam Shamiul , Islam Md Mazharul , Hossain Md Shafayat , Jaiswal Akhilesh , Aziz Ahmedullah
Published: April 2022

The scaling of the already matured complementary metal-oxide-semiconductor technology is steadily approaching its physical limit, motivating the quest for a suitable alternative. Cryogenic operation offers a promising pathway toward continued improvement in computing speed and energy efficiency without aggressive scaling. However, the memory wall bottleneck of the traditional von-Neumann architecture persists even at cryogenic temperature. That is where a compute-in-memory (CiM) architecture, which embeds computing within the memory unit, comes into play. Computations within the memory unit help to reduce the expensive data transfer between the memory and the computing units. Therefore, CiM provides extreme energy efficiency that can enable lower cooling cost at cryogenic temperature. In this work, we demonstrate CryoCiM, a cryogenic compute-in-memory framework utilizing a nonvolatile memory system based on the quantum anomalous Hall effect (QAHE). Our design can perform memory read/write and universal binary logic operations (NAND, NOR, and XOR). We custom design a peripheral circuit assembly that can perform the read/write and single-cycle in-memory logic operations. The utilization of a QAHE-based memory system promises robustness against process variations, through the usage of topologically protected resistive states for data storage. CryoCiM is a major step toward utilizing exclusively cryogenic phenomena to serve the dual purpose of storage and computation with ultra-low power (∼nano-watts) operations.
Amyloid-β and tau pathologies relate to distinctive brain dysconnectomics in preclinical autosomal-dominant Alzheimer’s disease
Authors: Guzmán-Vélez Edmarie , Diez Ibai , Schoemaker Dorothee , Pardilla-Delgado Enmanuelle , Vila-Castelar Clara , Fox-Fuller Joshua T. , Baena Ana , Sperling Reisa A. , Johnson Keith A. , Lopera Francisco , Sepulcre Jorge , Quiroz Yakeel T.
Published: April 2022

SIGNIFICANCE

Amyloid-β and tau, hallmark pathologies of Alzheimer’s disease (AD), are hypothesized to spread through brain functional networks that are critical for neural communication. Using high-resolution network analyses and positron emission tomography, we showed that greater tau burden was related to functional dysconnectivity of regions associated with memory function and increased connectivity of structures that are important for integrating information in cognitively unimpaired Presenilin-1 E280A carriers, who will develop early-onset AD dementia. These findings enlighten how brain pathology relates to distinct patterns of functional connectivity in regions that are essential for memory and information processing. Elucidating how brain pathology alters functional connections before individuals experience cognitive impairment could help detect AD early and predict disease progression and dementia risk.
Efficient control of western flower thrips by plastid-mediated RNA interference
Authors: Wu Mengting , Dong Yi , Zhang Qi , Li Shengchun , Chang Ling , Loiacono F. Vanessa , Ruf Stephanie , Zhang Jiang , Bock Ralph
Published: April 2022

Significance

Thrips are a group of piercing-sucking pest insects that do massive damage in agriculture and horticulture. The western flower thrip is a particularly notorious pest that has spread all over the world and is extremely difficult to control. In this work, we have shown that upon feeding, thrips take up substantial quantities of chloroplast RNA. When we expressed from the chloroplast genome long double-stranded RNAs that are targeted against essential thrip genes, the RNAs induced a potent RNA interference response and efficiently killed the insects. Our study demonstrates that an important group of nonchewing pest insects can be targeted by plant-mediated RNA interference and provides an efficient weapon to control thrips and other sucking plant pests.
High-precision tumor resection down to few-cell level guided by NIR-IIb molecular fluorescence imaging
Authors: Wang Feifei , Qu Liangqiong , Ren Fuqiang , Baghdasaryan Ani , Jiang Yingying , Hsu RuSiou , Liang Peng , Li Jiachen , Zhu Guanzhou , Ma Zhuoran , Dai Hongjie
Published: April 2022

Significance

Surgical removal of tumors has been performed to combat cancer for over a century by surgeons relying on visual inspection and experience to identify margins between malignant and healthy tissues. Herein, we present a rare-earth down-conversion nanoparticle–anti-CD105 conjugate for cancer targeting and a handheld imager capable of concurrent photographic imaging and fluorescence/luminescence imaging. An unprecedented tumor-to-muscle ratio was achieved by near-infrared-IIb (NIR-IIb, 1,500 to 1,700 nm) imaging during surgery, ∼100 times higher than previous organic dyes for unambiguous determination of tumor margin. The sensitivity/biocompatibility/safety of the probes and instrumentation developed here open a paradigm of imaging-guided surgery at the single-cell level, meeting all major requirements for clinical translation to combat cancer and save human lives.
Chemical–genetic interaction mapping links carbon metabolism and cell wall structure to tuberculosis drug efficacy
Authors: Koh Eun-Ik , Oluoch Peter O. , Ruecker Nadine , Proulx Megan K. , Soni Vijay , Murphy Kenan C. , Papavinasasundaram Kadamba , Reames Charlotte J. , Trujillo Carolina , Zaveri Anisha , Zimmerman Matthew D. , Aslebagh Roshanak , Baker Richard E. , Shaffer Scott A. , Guinn Kristine M. , Fitzgerald Michael , Dartois Véronique , Ehrt Sabine , Hung Deborah T. , Ioerger Thomas R. , Rubin Eric J. , Rhee Kyu Y. , Schnappinger Dirk , Sassetti Christopher M.
Published: April 2022

Significance

Efforts to improve tuberculosis therapy include optimizing multidrug regimens to take advantage of drug–drug synergies. However, the complex host environment has a profound effect on bacterial metabolic state and drug activity, making predictions of optimal drug combinations difficult. In this study, we leverage a newly developed library of conditional knockdown
Mycobacterium tuberculosis
mutants in which genetic depletion of essential genes mimics the effect of drug therapy. This tractable system allowed us to assess the effect of growth condition on predicted drug–drug interactions. We found that these interactions can be differentially sensitive to the metabolic state, and select in vitro–defined interactions can be leveraged to accelerate bacterial killing during infection. These findings suggest strategies for optimizing tuberculosis therapy.
An adaptive integral terminal sliding mode controller to track the human upper limb during front crawl swimming
Authors: Haghpanah Seyyed Arash , Khosrowpour Elham , Hematiyan Mohammad Rahim
Published: April 2022

Injuries are inevitable during swimming. The main goal of athletes especially competitive ones and coaches is to do the most mechanically effective movement patterns. In this case, biomechanical assessments could be beneficial in the management and prevention of injuries and pain in swimmers’ vulnerable joints. As the upper limb in swimming causes the highest propulsive force, the arm is exposed to more injuries. A skeletal model with 5 degrees of freedom is developed to simulate the swimmer's arm during front crawl swimming. This model includes shoulder and elbow joints with all of their degrees of freedom. An adaptive integral sliding mode (AITSM) controller is employed to track the desired joint trajectories during swimming. This controller can converge the tracking errors to zero in finite time. For tuning the controller gains regardless of the upper bounds of the system uncertainties, an adaptive controller is applied. The results demonstrate the performance of the AITSM strategy in tracking the desired trajectory of an underwater arm model during swimming. During the down sweep to catch phase, arm movements cause more stress in the shoulder than the elbow. The applied moment at the shoulder is almost triple of the elbow's moment. Therefore, the most vulnerable joint is the shoulder. By considering shoulder strength, the injury risk is predicted about 10% for the considered swimmer.

Highlights

The human upper limb during front crawl swimming is simulated.

A 5‐DOF skeletal model is considered to simulate the arm.

An adaptive integral sliding mode (AITSM) controller is employed to track the desired trajectory.

The results show that the controller has the proper performance to track the desired motion.

The most vulnerable joint is the shoulder and higher moments are induced at this joint.
IL-17A–producing γδT cells promote muscle regeneration in a microbiota-dependent manner
Authors: Mann Alexander O. , Hanna Bola S. , Muñoz-Rojas Andrés R. , Sandrock Inga , Prinz Immo , Benoist Christophe , Mathis Diane
Published: April 2022

Subsequent to acute injury, skeletal muscle undergoes a stereotypic regenerative process that reestablishes homeostasis. Various types of innate and adaptive immunocytes exert positive or negative influences at specific stages along the course of muscle regeneration. We describe an unanticipated role for γδT cells in promoting healthy tissue recovery after injection of cardiotoxin into murine hindlimb muscle. Within a few days of injury, IL-17A–producing γδT cells displaying primarily Vγ6+ antigen receptors accumulated at the wound site. Punctual ablation experiments showed that these cells boosted early inflammatory events, notably recruitment of neutrophils; fostered the proliferation of muscle stem and progenitor cells; and thereby promoted tissue regeneration. Supplementation of mice harboring low numbers of IL-17A+ γδT cells with recombinant IL-17A largely reversed their inflammatory and reparative defects. Unexpectedly, the accumulation and influences of γδT cells in this experimental context were microbiota dependent, unveiling an orthogonal perspective on the treatment of skeletal muscle pathologies such as catastrophic wounds, wasting, muscular dystrophies, and myositides.
Simple pendulum with speed-independent bearing friction
Authors: Mungan Carl E , Lipscombe Trevor C
Published: April 2022

Damping of an oscillator is often analyzed in terms of linear or quadratic drag as the object moves through a fluid such as air. Here attention is instead focused on the frictional torque in the bearing of a rigidly swinging pendulum. Two simple models are proposed to describe the bearing. First, it is considered to be two concentric cylinders with friction acting at one point of contact between them. Second, the bearing is taken to be composed of small balls in the race between the two cylinders, so that there are many points of contact over which the frictional force is distributed. The level of analysis in these two models is accessible to students in a first university course in calculus-based mechanics.
Topological band transition between hexagonal and triangular lattices with (p

x
, p

y
) orbitals
Authors: Hao Xiamin , Wu Weikang , Zhu Jiaojiao , Song Biyu , Meng Qingling , Wu Meimei , Hua Chenqiang , Yang Shengyuan A. , Zhou Miao
Published: April 2022

By combining tight-binding modelling with density functional theory based first-principles calculations, we investigate the band evolution of two-dimensional (2D) hexagonal lattices with (p

x
, p

y
) orbitals, focusing on the electronic structures and topological phase transitions. The (p

x
, p

y
)-orbital hexagonal lattice model possesses two flat bands encompassing two linearly dispersive Dirac bands. Breaking the A/B sublattice symmetry could transform the model into two triangular lattices, each featuring a flat band and a dispersive band. Inclusion of the spin–orbit coupling and magnetization may give rise to quantum spin Hall and quantum anomalous Hall (QAH) states. As a proof of concept, we demonstrate that half-hydrogenated stanene is encoded by a triangular lattice with (p

x
, p

y
) orbitals, which exhibits ferromagnetism and QAH effect with a topological gap of ∼0.15 eV, feasible for experimental observation. These results provide insights into the structure-property relationships involving the orbital degree of freedom, which may shed light on future design and preparation of 2D topological materials for novel electronic/spintronic and quantum computing devices.
Detailed magneto heat capacity analysis of SnAs topological superconductor
Authors: Sharma M M , Awana V P S
Published: April 2022

In this article, we report magneto heat capacity analysis of superconducting SnAs. Magneto heat capacity analysis of superconductors is an important tool to determine bulk superconductivity as well as the pairing mechanism of Cooper pairs. SnAs crystal is characterized through x-ray diffraction and x-ray photoelectron spectroscopy. Magneto transport measurements of studied SnAs superconductor evidenced presence of superconductivity at around 4 K, which persists up to an applied field of 250 Oe. The bulk nature of superconductivity is determined through AC susceptibility (χ) along with the heat capacity measurements. Magneto heat capacity measurements show SnAs to be a fully gapped s wave superconductor. This finding is well supported by calculated physical parameters like α (3.36), λ
e–ph (0.70) and ΔC
el/γT
c (1.41). Calculation of residual Sommerfeld coefficient (γ
res) at different fields, confirms node-less superconductivity in SnAs.
Study on memory characteristics of fin-shaped feedback field effect transistor
Authors: Han Shinick , Kim Younghyun , Son Donghee , Baac Hyoung Won , Won Sang Min , Shin Changhwan
Published: April 2022

The nonvolatile and volatile memory characteristics of feedback field-effect transistors (FBFETs) with nitride charge storage layers were theoretically studied. Because of the electrons and holes stored in the nitride layer, the threshold voltage (V
TH) window of 0.6 V was opened/observed. And, with the help of the formation of a positive feedback loop in the p+–n+–p–n+ doped silicon region in FBFET, it turned out that the read delay time of the FBFET for nonvolatile memory applications can be shorter than 1 ns. On the other hand, for the volatile memory applications, the FBFET can implement (a) non-destructive read operations owing to the self-sustaining feedback loop characteristic, and (b) a significantly long retention time which can suppress the power dissipation in refresh. Furthermore, the operation scheme of volatile memory mode can be simplified by setting gate voltage conditions for the hold and read operations to be identical to each other. The FBFET showed its on-state drive current of 6 × 10−5 A μm−1 and the on-/off-current ratio of 109. The potential of merging nonvolatile and volatile memory devices in a single cell is discussed and demonstrated in this work.
The influence of lightly doped p-GaN cap layer on p-GaN/AlGaN/GaN HEMT
Authors: Liu Kai , Wang Runhao , Wang Chong , Zheng Xuefeng , Ma Xiaohua , Bai Junchun , Cheng Bin , Liu Ruiyu , Li Ang , Zhao Yaopeng , Hao Yue
Published: April 2022

In this paper, the influence of a lightly doped p-GaN (p−-GaN) cap layer on p-GaN/AlGaN/GaN high electron mobility transistors (HEMTs) (LDP-HEMTs) was investigated. No difference in output or off-state breakdown characteristics was observed, but there was a negative shift in threshold voltage (V
TH). The gate leakage (V
GS = 7 V) dropped by three orders of magnitude, and the gate forward breakdown voltage and continuous operating voltage increased by 6.5 V and 2.5 V, respectively. It is worth noting that the gate characteristics are significantly optimized, which is ascribed to the employment of the p−-GaN cap layer. The simulations illustrate that the electric field is dispersed, and the electric peak is alleviated by the p−-GaN cap layer, thus suppressing the impact ionization and carrier injection in the high electric field. Furthermore, there is a negligible effect on the temperature reliability of V
TH based on the temperature-dependent characteristics in LDP-HEMTs. However, the temperature stability of the gate current (V
GS = 7 V) will worsen in LDP-HEMTs due to the difference in the conduction mechanism, compared with conventional p-GaN HEMTs.
Interesting and complex behaviour of Duffing equations within the frame of Caputo fractional operator
Authors: Ilhan Esin
Published: April 2022

The coupled system exemplifying the damped and driven oscillators (namely, Duffing equations) is examined with a familiar and robust numerical method. In the framework, we hired a reliable and most cited Caputo fractional operator to capture essential and stimulating behaviours of the hired physical model. The existence of the solution for the considered model is presented, and we captured the nature of the strange attractor for the Duffing equations with a period of the driving force. The effect of chaotic nature associated parameter is illustrated. The essence of generalizing the classical models is presented with plots, and associated consequences are demonstrated for the substantial time period.
A new attempt to identify long-term precursors for endogenous financial crises in the market correlation structures
Authors: Heckens Anton J , Guhr Thomas
Published: April 2022

Prediction of events in financial markets is every investor’s dream and, usually, wishful thinking. From a more general, economic and societal viewpoint, the identification of indicators for large events is highly desirable to assess systemic risks. Unfortunately, the very nature of financial markets, particularly the predominantly non-Markovian character as well as non-stationarity, make this challenge a formidable one, leaving little hope for fully fledged answers. Nevertheless, it is called for to collect pieces of evidence in a variety of observables to be assembled like the pieces of a puzzle that eventually might help to catch a glimpse of long-term indicators or precursors for large events—if at all in a statistical sense. Here, we present a new piece for this puzzle. We use the quasi-stationary market states that exist in the time evolution of the correlation structure in financial markets. Recently, we identified such market states relative to the collective motion of the market as a whole. We study their precursor properties in the US stock markets over 16 years, including two endogenous crises, the dot-com bubble burst and the pre-phase of the Lehman Brothers crash. We identify certain interesting features and critically discuss their suitability as indicators.
Avpd: An Anti-virus Model with Remote Thread Injection for Android Based on ResNet50
Authors: Yang Yuer , Chen Zeguang , Chen Shaobo , Du Zhuoyun , Luo Yuxin , Zhao Liangtian , Zhou Lifeng , Quan Yujuan
Published: April 2022

Most Android mobile anti-virus software in the industry is checked at the application level, and users familiar with the Android operating system are well aware that the use of virtual clicks, function execution, or shell commands can force the application to stop, which poses a threat to the real-time monitoring of anti-virus software. Moreover, the current mainstream anti-virus software in the industry can only let users manually uninstall or deactivate malicious apps when detected, which also makes the anti-virus software in Android mobile lose the ability of mobile anti-virus software to remove or delete viruses and Trojans automatically. To solve the problems above, in this paper, we train a mobile anti-virus model based on Resnet50 and proposes an Android mobile anti-virus method using remote thread injection - overriding the execution of malicious code by RTI means such as hook API, nulling related functions, rewriting related classes or functions to preserve the app as much as possible. In contrast, The model can identify malicious code with the highest accuracy. The model's recognition accuracy is up to 98.14%, and the malicious code blocking rate is up to 99.70% after recognition.