bluuebunny/crossref_metadata_2025 huggingface dataset:
Can pasture defoliation management targets be similar under full sun and shaded conditions?
Authors: Krahl Gustavo , Baldissera Tiago Celso , Pinto Cassiano Eduardo , Garagorry Fábio Cervo , Werner Simone Silmara , Lopes Cássio Felipe , Ribeiro Filho Henrique Mendonça Nunes
Published: August 2022

Context ​Defoliation management targets applied to forages under the full sun have not yet been properly evaluated for shaded environments such as occur in integrated crop–livestock systems with the presence of trees. Aims This study aimed to determine defoliation targets under full sun and shaded environments for the shade-tolerant perennial summer grass hybrid Axonopus catharinensis (giant missionary grass), widely used in pasture systems of South Brazil and Argentina. Methods Four pre-defoliation canopy heights (15, 25, 35 and 45 cm) and four defoliation severities (20%, 40%, 60% and 80% reduction in pre-defoliation canopy height) were evaluated. Plants were grown in 0.15 m3 wooden boxes filled with sand/vermiculite substrate (1:1 v/v) and irrigated with a complete nutrient solution. An artificial shade structure was made with wooden slats, reducing light intensity by 50% for shaded plants. Key results Herbage accumulation decreased by 54% in shaded plants compared with those under full sun. Regardless of the light environment, the lowest crude protein content (<150 g/kg dry matter) and the highest neutral detergent fibre content (>650 g/kg dry matter) were observed when the defoliation target height was >35 cm. Both shaded and full sun environments showed decreases in tiller density when defoliation severity was >60% of pre-defoliation canopy heights. Conclusions Pre-defoliation canopy heights >35 cm and defoliation severity >60% of pre-defoliation canopy height should be avoided when managing A. catharinensis, regardless of the light environment. Implications Recommended targets may be easily implemented by livestock producers and are similar for full sun and shade environments.
Disruption of mitochondria–sarcoplasmic reticulum microdomain connectomics contributes to sinus node dysfunction in heart failure
Authors: Ren Lu , Gopireddy Raghavender R. , Perkins Guy , Zhang Hao , Timofeyev Valeriy , Lyu Yankun , Diloretto Daphne A. , Trinh Pauline , Sirish Padmini , Overton James L. , Xu Wilson , Grainger Nathan , Xiang Yang K. , Dedkova Elena N. , Zhang Xiao-Dong , Yamoah Ebenezer N. , Navedo Manuel F. , Thai Phung N. , Chiamvimonvat Nipavan
Published: August 2022

The sinoatrial node (SAN), the leading pacemaker region, generates electrical impulses that propagate throughout the heart. SAN dysfunction with bradyarrhythmia is well documented in heart failure (HF). However, the underlying mechanisms are not completely understood. Mitochondria are critical to cellular processes that determine the life or death of the cell. The release of Ca
2+
from the ryanodine receptors 2 (RyR2) on the sarcoplasmic reticulum (SR) at mitochondria–SR microdomains serves as the critical communication to match energy production to meet metabolic demands. Therefore, we tested the hypothesis that alterations in the mitochondria–SR connectomics contribute to SAN dysfunction in HF. We took advantage of a mouse model of chronic pressure overload–induced HF by transverse aortic constriction (TAC) and a SAN-specific CRISPR-Cas9–mediated knockdown of
mitofusin-2
(
Mfn2
), the mitochondria–SR tethering GTPase protein. TAC mice exhibited impaired cardiac function with HF, cardiac fibrosis, and profound SAN dysfunction. Ultrastructural imaging using electron microscope (EM) tomography revealed abnormal mitochondrial structure with increased mitochondria–SR distance. The expression of Mfn2 was significantly down-regulated and showed reduced colocalization with RyR2 in HF SAN cells. Indeed, SAN-specific
Mfn2
knockdown led to alterations in the mitochondria–SR microdomains and SAN dysfunction. Finally, disruptions in the mitochondria–SR microdomains resulted in abnormal mitochondrial Ca
2+
handling, alterations in localized protein kinase A (PKA) activity, and impaired mitochondrial function in HF SAN cells. The current study provides insights into the role of mitochondria–SR microdomains in SAN automaticity and possible therapeutic targets for SAN dysfunction in HF patients.
Commentary Article: Association of Multidisciplinary Education and Research in Substance use and Addiction's (AMERSA) 2021 Transforming Care through Evidence and Policy Conference: Tackling Stigma and Giving Voice to Lived Experience
Authors: Oliva Elizabeth M. , Bagley Sarah M. , Bottner Richard , Northup Rebecca , MacLane-Baeder Doreen
Published: August 2022

This commentary provides an overview of the Association of Multidisciplinary Education and Research in Substance use and Addiction (AMERSA) 2021 annual conference: Transforming Care Through Evidence and Policy. The topics covered during the conference were especially critical given the unprecedented rise in drug overdose deaths and continued impact of the COVID-19 pandemic on substance use and addiction. The importance of tackling stigma and ensuring that we partner with those with lived experience to have maximal impact was highlighted.
Use of plasma oxidation for conversion of metal salt infiltrated thin polymer films to metal oxide
Authors: Conway J , Snelgrove M , Yadav P , Shiel K , Lundy R , Selkirk A , O’Connor R , Morris M A , Turner M M , Daniels S
Published: August 2022

Oxygen plasma treatments for conversion of metal salt infiltrated polymer films to metal oxide films using an asymmetrical capacitively coupled plasma system were investigated. Hydroxylated Poly-2-Vinylpyridine (P2VP-OH) thin films grafted to silicon were exposed to metal salt-solvent solutions which swell the polymer enabling metal ion infiltration. Exposing the resulting film to oxygen plasma resulted in formation of polymer-free metal oxide films. Atomic oxygen and positive ions present in plasma can both influence the process outcome. A design of experiment approach was used to investigate the impact of radio frequency (RF) power, gas pressure and process time on plasma composition and the resulting metal oxide films. A combination of Langmuir probe, retarding field energy analyser and optical emission spectroscopy measurements were used to monitor the plasma. The samples surfaces were examined using x-ray photoelectron spectroscopy, ellipsometry, transmission electron microscopy and energy dispersive x-ray analysis. Gas pressure and RF power were found to strongly influence both ion energy, and atomic oxygen to molecular ion ratios [O]/[O2
+] in the plasma which impacted the resulting surface layer. For the plasma conditions investigated conversion to a metal oxide was achieved in minutes. Sputter contamination was found to be significant in some cases.
A comparative study of electrochemical and electrostatic doping modulation of magnetism in Fe3O4 via ultracapacitor structure
Authors: Gu Fangchao , Zhang Leqing , Li Zhaohui , Zhang Jie , Pan Yuanyuan , Li Qinghao , Li Hongsen , Qin Yufeng , Li Qiang
Published: August 2022

Electric field control of magnetism can boost energy efficiency and have brought revolutionary breakthroughs in the development of widespread applications in spintronics. Electrolyte gating plays an important role in magnetism modulation. In this work, reversible room-temperature electric field control of saturation magnetization in Fe3O4 via a supercapacitor structure is demonstrated with three types of traditional gate electrolytes for comparison. Different magnetization response and responsible mechanisms are revealed by Operando magnetometry PPMS/VSM and XPS characterization. The main mechanism in Na2SO4, KOH aqueous electrolytes is electrochemical effect, while both electrochemical and electrostatic effects were found in LiPF6 organic electrolyte. This work offers a kind of reference basis for selecting appropriate electrolyte in magnetism modulation by electrolyte-gating in the future, meanwhile, paves its way towards practical use in magneto-electric actuation, voltage-assisted magnetic storage, facilitating the development of high-performance spintronic devices.
Pavement crack measurement based on aerial 3D reconstruction and learning-based segmentation method
Authors: Jiang Shang , Gu Siyang , Yan Zhiyu
Published: August 2022

Rapid inspection of urban road cracks is vital to maintain traffic smoothness and ensure traffic safety. A rapid pavement crack inspection method uses low-altitude aerial images captured by an unmanned aerial system (UAS) and deep-learning aided 3D reconstruction, and a learning-based object segmentation algorithm is proposed to measure road cracks automatically. The contributions include: (a) An efficient 3D reconstruction method for low-altitude aerial images captured by a UAS is proposed, which applies an instance segmentation network to segment road targets from raw images with complex backgrounds first and then performs structure from motion to reconstruct a large-scale road orthophoto from a large number of aerial images. (b) To detect cracks from the reconstructed large-size road orthophoto, a sliding window algorithm and U-Net model optimized with a transformer structure are used to automatically identify and segment the cracks from the orthophoto at the pixel level. Then, a connected domain feature analysis method is used to measure the road crack length. The proposed method is applied to detection of road cracks in a 1.5 km2 area of a city. The results show that the proposed method can effectively and accurately detect cracks and measure the length of cracks in the 4-km-long road, which proves the practicality of the proposed method.
Noise reduction and feature enhancement of hob vibration signal based on parameter adaptive VMD and autocorrelation analysis
Authors: Yuan Yanfei , Yan Ping , Zhou Han , Huang Qin , Wu Dayuan , Zhu Junhan , Ni Zhongming
Published: August 2022

The vibration signal of the hobbing machine is susceptible to changes in the frequency domain distribution owing to the influence of the machine’s inherent vibration and random pulses, which affects the condition monitoring and wear prediction of the hobbing machine. Variational mode decomposition (VMD) can compensate for the mode mixing problem of ensemble empirical mode decomposition method owing to its inherent equivalent filtering property. However, the decomposition performance of VMD depends heavily on two hyperparameters that need to be set in advance, i.e. the number of bandwidth-limited intrinsic mode functions (BLIMFs) K and the penalty factor α. Thus, a hybrid signal denoising and feature enhancement method based on parameter adaptive variational mode decomposition (PAVMD) and autocorrelation analysis is proposed in this study. First, a gradient-based optimizer is introduced to optimally select the decomposition parameter of VMD, and then a series of BLIMFs are obtained via VMD. Further, an evaluation criterion called enhanced periodic modulation intensity based on autocorrelation analysis is built to quantify the noise-related degree of each BLIMF. Finally, the denoised signal is obtained based on the proposed reconstruction strategy. The comparison with other methods in both the simulation and the actual signal analysis reveals that the proposed method has a better performance in terms of eliminating the high-frequency noise, reserving higher effective frequencies, and the evaluation indicator.
A combined TEM and SAXS study of the growth and self-assembly of ultrathin Pt nanowires
Authors: McGuire Scott C , Zhang Yugang , Wong Stanislaus S
Published: August 2022

Ultrathin Pt nanowires possess high activity for various electrocatalytic applications. However, little work has focused on understanding their growth mechanisms. Herein, we utilize a combination of time-dependent, ex situ transmission electron microscopy (TEM) and small angle x-ray scattering (SAXS) techniques to observe the growth process in addition to associated surfactant-based interactions. TEM images indicate that initially nanoparticles are formed within 30 s; these small ‘seed’ particles quickly elongate to form ultrathin nanowires after 2 min. These motifs remain relatively unchanged in size and shape up to 480 min of reaction. Complementary SAXS data suggests that the initial nanoparticles, which are coated by a surfactant bilayer, arrange into a bcc superlattice. With increasing reaction time, the bcc lattice disappears as the nanoparticles grow into nanowires, which then self-assemble into a columnar hexagonal structure in which the individual nanowires are covered by a CTAB monolayer. The hexagonal structure eventually degrades, thereby leading to the formation of lamellar stacking phases comprised of surfactant bilayers. To the best of our knowledge, this is the first time that SAXS has been used to monitor the growth and self-assembly of Pt nanowires. These insights can be used to better understand and rationally control the formation of anisotropic motifs of other metallic nanostructures.
Intratidal compliance of the lung and the total respiratory system
Authors: Dzierzawski Patryk , Oswalt Jakob , Wirth Steffen , Schumann Stefan
Published: August 2022

Objective. The worldwide rising quantity of surgeries and the corresponding need of mechanical ventilation means a rising number of patients are at risk of suffering from post-operative pulmonary complications. To prevent this risk, individual mechanics of the lung should be considered when setting the parameters of mechanical ventilation. Intratidal compliance analysis based on transpulmonal pressure would provide an estimate for individual lung mechanics. The downside of such measure, however, is its invasiveness. Accurate measurement requires recording of the esophageal pressure as surrogate for the actual pleural pressure. Measuring pressure at the airway opening is considerably easier, but the resulting mechanics of the respiratory system may not represent the actual lung mechanics in a straightforward fashion. Approach. In order to evaluate if the mechanics of the lungs are represented by analysis of the mechanics of the respiratory system we determined intratidal dynamic compliance-volume profiles of both in 23 lung-healthy mechanically ventilated patients undergoing elective surgery. We also compared the accuracy of the compliance profiles resulting from analysis of the total breath with those resulting from the analysis of inspiration data only. Main results. When the whole breath was analyzed 54.3%, and with only inspiration data 69.6%, of compliance profiles of the respiratory system matched those of the lung. With both approaches profiles of the lung and the respiratory system matched or deviated by only one neighboring step (75% whole breath, 91.3% inspiration only), and never contradicted each other. Significance. Compliance profiles calculated from volume and pressure data of the respiratory system are an adequate surrogate for the compliance profiles of the lungs of lung-healthy patients. Therefore, invasive assessment of esophageal pressure for achievement of intrapleural pressure is unnecessary. The compliance profiles based on only inspiratory data appear more sensitive for indicating intratidal derecruitment than those based on data of the whole breath.
Kinetic investigation of plasma catalytic synthesis of ammonia: insights into the role of excited states and plasma-enhanced surface chemistry
Authors: Sun Jintao , Chen Qi , Zhao Xuteng , Lin He , Qin Wanyue
Published: August 2022

The present work investigates the kinetics of catalytic ammonia synthesis in a N2/H2 mixture activated by a nanosecond pulsed discharge plasma experimentally and numerically. X-ray diffraction, high-resolution transmission electron microscopy and x-ray photoelectron spectroscopy are combined to characterize the morphology and surface electronic properties of the catalyst. Special attention is placed on the role of excited species in promoting the formation of important intermediates and the plasma-enhanced surface chemistry. A detailed kinetic mechanism consisting of atoms, radicals, excited species, molecules, ions, and surface species is developed and studied by incorporating a set of the electron impact reactions, reactions involving excited species, ionic reactions, direct and dissociative adsorption reactions, and surface reactions. A zero-dimensional model incorporating the plasma kinetics solver is used to calculate the temporal evolution of species densities in a N2/H2 plasma catalysis system. The results show that the coupling of Fe/γ–Al2O3 catalyst with plasma is much more effective in ammonia synthesis than the Fe/γ–Al2O3 catalyst alone and plasma alone. The numerical model has a good agreement with experiments in ammonia formation. The path flux analysis shows the significant roles of excited species N(2D), H2(v1), N2(v) in stimulating the formation of precursors NH, NH2, and adsorbed N(s) through the pathways N(2D) + H2 → NH + H, H2(v1) + NH → NH2 + H and N2(v) + 2Fe(s) → N(s) + N(s), respectively. Furthermore, the results show that the adsorption reaction N + Fe(s) → N(s) and Eley–Ridel interactions N(s) + H → NH(s), N + H(s) → NH(s), NH + H(s) → NH2(s) and NH2 + H(s) → NH3(s) can kinetically enhance the formation of ammonia, which further highlights the plasma-enhanced surface chemistry. This work provides new insights into the roles of excited species and plasma-enhanced surface chemistry in the plasma catalytic ammonia synthesis.
Surface processes involving nitrogen molecules and atoms on silica surface at low temperature: the role of energy exchanges
Authors: Rutigliano Maria , Pirani Fernando
Published: August 2022

The dynamics of elementary surface processes, promoted by nitrogen atoms and molecules impacting a silica surface, has been investigated by adopting a semiclassical scattering method. The appropriate treatment of the long-range interaction forces emphasized the crucial control exercised by the weakly bound precursor state on the stereo-dynamics of all basic elementary processes occurring at the gas-surface inter-phase. Molecular dynamics simulations have highlighted the role of vibrationally excited molecules in plasma dynamics. Indeed, N2 molecules, impinging the surface in low-medium vibrational levels, conserve the initial vibration state while are inelastically scattered, rotationally excited and translationally colder. Moreover, N2 molecules nascent from the atomic recombination on the surface have a fair probability of forming at very high vibrational levels, with a consistent part of reaction exothermicity transferred to the translational energy. Consequently, the surface induces a strong non-equilibrium condition, influencing directly the dynamics of processes occurring in the plasma bulk.
A computational study of accelerating, steady and fading negative streamers in ambient air
Authors: Guo Baohong , Li Xiaoran , Ebert Ute , Teunissen Jannis
Published: August 2022

We study negative streamers in ambient air using a 2D axisymmetric fluid model. Depending on the background electric field, we observe accelerating, steady and fading negative streamers. Fading occurs in low background fields, when negative streamers lose their field enhancement and when their velocities become comparable to their maximal electron drift velocities. Our focus is on the steady propagation mode, during which streamer properties like radius and velocity hardly change. However, this mode is unstable, in the sense that a small change in conditions leads to acceleration or deceleration. We observe steady negative streamers in background fields ranging from 9.19 kV cm−1 to 15.75 kV cm−1, indicating that there is no unique steady propagation field (or stability field). Another finding is that steady negative streamers are able to keep propagating over tens of centimeters, with only a finite conductive length behind their heads, similar to steady positive streamers. Approximately linear relationships are observed between the optical diameter and properties like the streamer velocity and the streamer head potential. From these linear relations, we obtain rough lower bounds of about 0.27 mm to 0.35 mm for the minimal optical diameter of steady negative streamers. The lowest background field in which a steady negative streamer could be obtained is 9.19 kV cm−1. In contrast, steady positive streamers have recently been obtained in a background field as low as 4.05 kV cm−1. We find that the properties of steady negative and positive streamers differ significantly. For example, for steady negative streamers the ratio between streamer velocity and maximal electron drift velocity ranges from about 2 to 4.5, whereas for steady positive streamers this ratio ranges from about 0.05 to 0.26.
Multiband effects in thermoelectric and electrical transport properties of kagome superconductors AV3Sb5 (A = K, Rb, Cs)
Authors: Mi Xinrun , Xia Wei , Zhang Long , Gan Yuhan , Yang Kunya , Wang Aifeng , Chai Yisheng , Guo Yanfeng , Zhou Xiaoyuan , He Mingquan
Published: August 2022

We studied the effects of multiband electronic structure on the thermoelectric and electrical transport properties in the normal state of kagome superconductors AV3Sb5 (A = K, Rb, Cs). In all three members, the multiband nature is manifested by sign changes in the temperature dependence of the Seebeck and Hall resistivity, together with sublinear response of the isothermal Nernst and Hall effects to external magnetic fields in the charge ordered state. Moreover, ambipolar transport effects appear ubiquitously in all three systems, giving rise to sizable Nernst signal. Finally, possible origins of the sign reversal in the temperature dependence of the Hall effect are discussed.
Unconditionally secure digital signatures implemented in an eight-user quantum network*
Authors: Pelet Yoann , Puthoor Ittoop Vergheese , Venkatachalam Natarajan , Wengerowsky Sören , Lončarić Martin , Neumann Sebastian Philipp , Liu Bo , Samec Željko , Stipčević Mario , Ursin Rupert , Andersson Erika , Rarity John G , Aktas Djeylan , Joshi Siddarth Koduru
Published: August 2022

The ability to know and verifiably demonstrate the origins of messages can often be as important as encrypting the message itself. Here we present an experimental demonstration of an unconditionally secure digital signature (USS) protocol implemented for the first time, to the best of our knowledge, on a fully connected quantum network without trusted nodes. We choose a USS protocol which is secure against forging, repudiation and messages are transferrable. We show the feasibility of unconditionally secure signatures using only bi-partite entangled states distributed throughout the network and experimentally evaluate the performance of the protocol in real world scenarios with varying message lengths.
Momentum transfer models of interacting dark energy
Authors: Linton Mark S. , Crittenden Robert , Pourtsidou Alkistis
Published: August 2022

We consider two models of interacting dark energy, both of which interact only through momentum exchange. One is a phenomenological one-parameter extension to wCDM, and the other is a coupled quintessence model described by a Lagrangian formalism. Using a variety of high and low redshift data sets, we perform a global fitting of cosmological parameters and compare to ΛCDM, uncoupled quintessence, and wCDM. We find that the models are competitive with ΛCDM, even obtaining a better fit when certain data sets are included.
Capture of primordial black holes in extrasolar systems
Authors: Lehmann Benjamin V. , Webber Ava , Ross Olivia G. , Profumo Stefano
Published: August 2022

The vast datasets associated with extrasolar systems promise to offer sensitive probes of new physics in the near future. We consider the possibility that such systems may capture primordial black holes (PBHs) or other exotic compact objects, giving rise to unique observational signatures. We estimate the rate of captures by extrasolar systems, accounting for several distinct mechanisms. We find that the capture rate is negligible unless PBHs account for the entirety of dark matter in a narrow mass range just above the threshold of existing constraints from evaporation. In this scenario, luminous evaporating PBHs may be detectable by exoplanet searches.
The processing network of high-frequency acoustoelectric signal in the living rat brain
Authors: Song Xizi , Huang Peishan , Chen Xinrui , Xu Minpeng , Ming Dong
Published: August 2022

Objective. Acoustoelectric brain imaging (ABI) is a potential noninvasive electrophysiological neuroimaging method with high spatiotemporal resolution. At the focal spot of the focused ultrasound, with the couple of acoustic and electric fields, high-frequency acoustoelectric (HF AE) signal is generated. Because the brain is a volume conductor, HF AE signal can be detected in other brain cortex. The processing of HF AE signal is critical for improving decoding precision, further improving the spatial resolution performance of ABI. This study investigates the processing network of HF AE signal in the living rat brain. Approach. When HF AE generated on the left primary visual cortex (V1-L), low-frequency (LF) electroencephalography and HF AE signals on different cortex were recorded at the same time. Firstly, AE signal on different sides of the brain cortex were compared, including prefrontal cortex (FrA) and primary somatosensory cortex (S1FL). Then, we constructed and analyzed functional networks of two signals. Main results. In the same cortex, HF AE signal on the right side had stronger intensity. And compared with LF networks, HF AE network had larger global efficiency and shorter characteristic path length, denoting the stronger processing and transmission of AE signal. Additionally, in HF AE network, the node had significantly increased local properties and the connection were concentrated in the occipital lobe, reflecting the occipital lobe plays an important role in the processing. Significance. Experiment results demonstrate that, compared with LF network, HF AE network is more efficient and had stronger transmission capabilities. And the connection of HF AE network is concentrated in the occipital lobe. This work preliminarily reveals the HF AE signal processing, which is significant for improving the ABI quality and provides a new insight for understanding the brain HF signal.
AI Acceleration Enabled by Nanoelectronic Memristive Devices
Authors: Bordanov I A , Zuev A D , Danilin S N , Khranilov V P , Bukvarev E A , Kim S , Gryaznov E G , Mikhaylov A N , Shchanikov S A
Published: August 2022

Here we present an analysis of the current state in the field of development of hardware accelerators of artificial intelligence (AI). Despite the fairly good progress made over the past decades, this area is experiencing a number of significant difficulties in its development. The solution to this problem lies in the application of new approaches to the organization of computing, in particular, computing in memory enabled by nanoelectronic memristive devices. We provide an overview of state-of-art systems, as well as our own version of the experimental concept of AI accelerators based on metal-oxide memristive devices and the massively parallel architecture for information processing.
Investigation of material heating under the action of ultrashort laser pulses
Authors: Kharkova A V , Khorkov K S , Egorova A V
Published: August 2022

The aim of this work was to study the heating of an AISI 304 plate in the ablative mode of femtosecond laser pulses. The variable parameter was the change in the speed of movement of the laser beam over the treated surface. The paper presents the results of measuring the heating temperature of the sample surface exposed to laser radiation without scanning laser radiation with different pulse energies. The results of the dependence of the heating of the material surface on the speed of movement of the laser radiation with a constant number of acting pulses are presenting.
Research of the physical and mechanical properties of AISI 321 steel manufactured by selective laser melting
Authors: Zhdanov A V , Raznoschikov A S , Voznesenskaya A A , Poltorakova K S , Belyaev I V
Published: August 2022

In this paper, the problems of creating parts by selective laser melting from AISI 321 powder material are considered. Samples were made from powder material with a granulometric composition of 10-63 microns at a selective laser melting plant. Microslips were made to study the physical and mechanical properties. The structure of the samples and their porosity were evaluated using optical microscopy. The change of physical and mechanical properties depending on the change in the scanning speed is investigated. The connection between the modes of selective laser melting and the physical and mechanical properties of the resulting products has been established.
Birefringent tuner for narrowband alexandrite laser
Authors: Putilov A G , Antipov A A , Shepelev A E , Osipov A V , Arakelian S M
Published: August 2022

This article discusses the possibility of using Lyot interference-polarization tuners to create tunable lasers. The use of various variations and layouts of phase-shifting plates makes it possible to generate both dual-wave and single-wave radiation with the possibility of tuning. The tuning range depends both on the specific type of tuner used and on the parameters of the cavity and active medium. Dual-wave and single-wavelength generation of an alexandrite laser is demonstrated.
Deflection of particles of a laser erosion plume under the action of a high-voltage electrostatic field during ablation processing of titanium
Authors: Firsov I V , Zolotov A N , Efremov I M , Egorova A V
Published: August 2022

The ablative particles of the laser erosion torch during the processing of titanium with subpicosecond pulses were analyzed for vertical deflection under the action of an electrostatic field. The installation of a solid-state ytterbium laser with a radiation wavelength of 1030 nm was used. The photographs of the registered deviations of ablation particles in the region of propagation of the electrostatic field were obtained. The dependence of the vertical deflections of ablated particles on the laser pulse energy and the distance from the electrodes to the target is calculated.
Fractal models of the PbTe nanocluster structures on a solid surface
Authors: Bukharov D N , Abramov A S , Novikova O A , Samyshkin V D
Published: August 2022

A fractal approach is proposed for modeling systems of PbTe nanoclusters on a solid surface. The systems under consideration were generated by solid-phase laser modification. For the obtained samples, their fractal dimension was estimated. In accordance with the proximity to it, the corresponding chaotic fractal structures were selected.
Topological photonics – 4D-laser technology for nanoelectronics on new physical principles to create the element base of next generation
Authors: Kucherik A , Kutrovskaya S , Bukharov D , Khudaiberganov T
Published: August 2022

In the paper we consider femtonanophotonics of the topological controlled low-dimensional dynamic structures in thin films induced by laser radiation on the surface of solids, using the achievements of quantum technologies and nonlinear dynamics for different regimes of electroconductivity.

We completed several laser procedures for obtaining nanostructures and thin films with controllable topology. They occur under the development of different nonlinear processes in the system (thermodiffusion, gas-dynamic evaporation in pore-like structures with bubbles, ablation products, ballistic movement of the particles in liquid). A simple 2-steps mechanism for enhancement of quantum behavior (e.g. in electroconductivity) exists for different conditions.

First, when inelastic length l
inelastic > a
cluster (size of cluster) we have no incoherent electron-phonon (e-ph) scattering, and coherent process occurs with scale ℓcoh.

Second, when de Broglie length λdB ≡ ℓcoh > Λ (Λ – spatial period of the nanoparticle distribution) the coherent tunneling without loss occurs, and a long-range order with interference of the states takes place in the medium due to lattice structure in system.

Under such conditions, the electroconductivity enhancement can result in paradoxical phenomenon when electroconductivity in granulated structure may be higher than in monolith sample due to many surface/boundary units – like topological states in topological insulator.
Features of the formation of bound states of optical phonons in nanostructures – the role of anharmonism
Authors: Arakelyan M
Published: August 2022

In this paper, we discuss the features of the formation of bound states of phonons and the role of anharmonism for such a formation in a dimensionally quantized system in comparison with bulk sample.
Distribution of laser radiation in opaque porous media
Authors: Voznesenskaya A A , Raznoschikov A S , Galkin A F , Oparin E S , Zavitkov A V , Loktev A S , Gusev D S
Published: August 2022

The work is aimed at studying the interaction of laser radiation and powder material, in particular, the nature of propagation and absorption of laser radiation in a porous medium. Measurements of the nature of propagation and interaction of laser radiation with a powder material were carried out using a low-power laser in the “before reflow” mode. The paper presents the results of measuring the intensity of the passage of a laser beam through layers of powder material made of an aluminum alloy AlSi10Mg with an average fraction of 30 μm of various thicknesses. The results of measuring the heating of the powder material under the action of laser radiation and the dependence of the depth of penetration of the laser beam into the powder material are presented.
Design of multi-layer grid in a giant electrostatic collection vessel of ultra-high sensitivity radon monitor
Authors: Mo Yixiang , Tang Jianfeng , Fan Zhongkai , Hu Tao , Lin Fen , Xie Ruomei , Yuan Shuai , Liu Shuaibin , Yuan Hongzhi , Tan Yanliang
Published: August 2022

Developing an ultra-high sensitivity electrostatic
collection radon monitor benefits the scientific experiments of
China Jinping Underground Laboratory. Here, a one cubic meter
electrostatic collection vessel with a multi-layer hemispherical
metal grid was designed to increase the collection efficiency of
positively charged Po-218 ions. The 3D model of the giant
electrostatic collection vessel was constructed using the COMSOL
Multiphysics simulation software, and the potential and electric
field distributions in the vessel were simulated. Numerical
simulation results were obtained according to the different radii
and voltages applied to the grid. The electric field between the
vessel wall and grid, between two grids, and between the grid and
surface of the PIPS detector must be set uniformly to reduce the
collection time of the positively charged Po-218 ions. Simulation
results showed that setting a charged metal grid in the vessel can
optimize the electric field distribution, and setting a two-layer
charged metal grid in the giant vessel can further increase the cost
performance. The average collection times of the electrostatic
collection vessel with the two-layer grid along the vertical and
oblique lines approximately 15% and 13% of that without the
grid. The rates of positively charged Po-218 ions that could pass
through the one and two-layer metal grids were 86.78% and
50%. Optimizing the electric field can greatly increase the
sensitivity of radon monitors and reduce the humidity restrictions.
ACHINOS: a multi-anode read-out for position reconstruction and tracking with spherical proportional counters
Authors: Katsioulas I. , Knights P. , Manthos I. , Matthews J. , Neep T. , Nikolopoulos K. , Ward R.
Published: August 2022

The spherical proportional counter is a versatile gaseous detector with physics applications ranging from rare event searches to fast neutron spectroscopy. In its simplest form, the detector operates with a single channel read-out, and uses pulse-shape information to reconstruct the interaction radius, which is used for background discrimination and target volume definition. Recent developments in the read-out instrumentation have enabled the use of a multi-anode read-out structure, ACHINOS. The multiple anodes provide information about the interaction position which, coupled with the radial information, can be used to reconstruct an ionisation track. This ability has implications for several applications of the detector, for example, enhanced background discrimination in rare event searches.
Precision antihydrogen annihilation reconstructions using the ALPHA-g detector
Authors: Woosaree Pooja
Published: August 2022

The ALPHA (Antihydrogen Laser PHysics Apparatus) collaboration aims to test fundamental symmetries with matter and antimatter by testing CPT (charge conjugation, parity reversal, time reversal) theory and observing whether antimatter follows Einstein’s Weak Equivalence Principle (WEP), where the acceleration due to gravity that a body experiences is independent of its structure or composition. A measurement of the gravitational mass of antimatter has never been done before, as previous experiments used charged particles, which meant the experiments were dominated by electromagnetic forces. The ALPHA-g apparatus will use electrically neutral antihydrogen atoms produced in a vertical Penning-Malmberg trap and hold the antihydrogen in a magnetic well. Once the antihydrogen is released, the position of the resulting annihilations can be reconstructed with a radial time projection chamber (rTPC) surrounding the trapping volume. Tracing the annihilation position within the rTPC is imperative to measuring the gravitational mass of antihydrogen. These proceedings will highlight simulations of antihydrogen annihilations, and how to calibrate the detector for z-positions. This data will be used to measure the gravitational mass of antihydrogen; an important measurement in testing the fundamental symmetry of matter and antimatter. The ALPHA-g apparatus is currently being commissioned at CERN, and the first gravitational measurements of antihydrogen are underway.
Live fish learn to anticipate the movement of a fish-like robot
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Authors: Bierbach David , Gómez-Nava Luis , Francisco Fritz A , Lukas Juliane , Musiolek Lea , Hafner Verena V , Landgraf Tim , Romanczuk Pawel , Krause Jens
Published: August 2022

The ability of an individual to predict the outcome of the actions of others and to change their own behavior adaptively is called anticipation. There are many examples from mammalian species—including humans—that show anticipatory abilities in a social context, however, it is not clear to what extent fishes can anticipate the actions of their interaction partners or what the underlying mechanisms are for that anticipation. To answer these questions, we let live guppies (Poecilia reticulata) interact repeatedly with an open-loop (noninteractive) biomimetic robot that has previously been shown to be an accepted conspecific. The robot always performed the same zigzag trajectory in the experimental tank that ended in one of the corners, giving the live fish the opportunity to learn both the location of the final destination as well as the specific turning movement of the robot over three consecutive trials. The live fish’s reactions were categorized into a global anticipation, which we defined as relative time to reach the robot’s final corner, and a local anticipation which was the relative time and location of the live fish’s turns relative to robofish turns. As a proxy for global anticipation, we found that live fish in the last trial reached the robot’s destination corner significantly earlier than the robot. Overall, more than 50% of all fish arrived at the destination before the robot. This is more than a random walk model would predict and significantly more compared to all other equidistant, yet unvisited, corners. As a proxy for local anticipation, we found fish change their turning behavior in response to the robot over the course of the trials. Initially, the fish would turn after the robot, which was reversed in the end, as they began to turn slightly before the robot in the final trial. Our results indicate that live fish are able to anticipate predictably behaving social partners both in regard to final movement locations as well as movement dynamics. Given that fish have been found to exhibit consistent behavioral differences, anticipation in fish could have evolved as a mechanism to adapt to different social interaction partners.
Thrust and torque production of a squid-inspired swimmer with a bent nozzle for thrust vectoring
Authors: Luo Yang , Xiao Qing , Zhu Qiang , Pan Guang
Published: August 2022

A three-dimensional pulsed-jet propulsion model consisting of a flexible body and a steerable bent nozzle in tethered mode is presented and studied numerically. By prescribing the body deformation and nozzle angle, we examine the flow evolution and propulsive/turning performance via thrust vectoring. Our results show that the vortex ring is no longer axis-symmetric when the jet is ejected at an angle with the incoming flow. A torque peak is observed during jetting, which is mainly sourced from the suction force (negative pressure) at the lower part of the internal nozzle surface when the flow is directed downward through an acute angle. After this crest, the torque is dominated by the positive pressure at the upper part of the internal nozzle surface, especially at a relatively low jet-based Reynolds number (O(102)). The torque production increases with a larger nozzle bent angle as expected. Meanwhile, the thrust production remains almost unchanged, showing little trade-off between thrust and torque production which demonstrates the advantage of thrust vectoring via a bent nozzle. By decoupling the thrust at the internal and outer surfaces considering special characteristics of force generation by pulsed-jet propulsion, we find that variations in Reynolds number mostly affect the viscous friction at the outer surfaces. The influence of the maximum stroke ratio is also studied. Results show that both the time-averaged thrust and the torque decrease at a larger stroke ratio.
Modeling the musculoskeletal system of an insect thorax for flapping flight
Authors: Ando Noriyasu , Kono Tokuro , Ogihara Naomichi , Nakamura Sakiko , Yokota Hideo , Kanzaki Ryohei
Published: August 2022

Indirect actuation of the wings via thoracic deformation is a unique mechanism widely observed in flying insect species. The physical properties of the thorax have been intensively studied in terms of their ability to efficiently generate wingbeats. The basic mechanism of indirect wing actuation is generally explained as a lever model on a cross-sectional plane, where the dorsoventral movement of the mesonotum (dorsal exoskeleton of the mesothorax) generated by contractions of indirect muscles actuates the wing. However, the model considers the mesonotum as an ideal flat plane, whereas the mesonotum is hemispherical and becomes locally deformed during flight. Furthermore, the conventional model is two-dimensional; therefore, three-dimensional wing kinematics by indirect muscles have not been studied to date. In this study, we develop structural models of the mesonotum and mesothorax of the hawkmoth Agrius convolvuli, reconstructed from serial cross-sectional images. External forces are applied to the models to mimic muscle contraction, and mesonotum deformation and wing trajectories are analyzed using finite element analysis. We find that applying longitudinal strain to the mesonotum to mimic strain by depressor muscle contraction reproduces local deformation comparable to that of the thorax during flight. Furthermore, the phase difference of the forces applied to the depressor and elevator muscles changes the wing trajectory from a figure eight to a circle, which is qualitatively consistent with the tethered flight experiment. These results indicate that the local deformation of the mesonotum due to its morphology and the thoracic deformation via indirect power muscles can modulate three-dimensional wing trajectories.
Independent control of molecular weight, concentration, and stiffness of hyaluronic acid hydrogels
Authors: Townsend Jakob M , Sanders Megan E , Kiyotake Emi A , Detamore Michael S
Published: August 2022

Hyaluronic acid (HA) hydrogels have been used for a multitude of applications, perhaps most notably for tissue engineering and regenerative medicine, owing to the versatility of the polymer and its tunable nature. Various groups have investigated the impact of hydrogel parameters (e.g. molecular weight, concentration, stiffness, etc) in vitro and in vivo to achieve desired material performance characteristics. A limitation in the literature to date has been that altering one hydrogel parameter (a ‘manipulated variable’) to achieve a given hydrogel characteristic (a ‘controlled variable’) changes two variables at a time (e.g. altering molecular weight and/or concentration to investigate cell response to stiffness). Therefore, if cell responses differ, it may be possible that more than one variable caused the changes in observed responses. In the current study, we leveraged thiol-ene click chemistry with a crosslinker to develop a method that minimizes material performance changes and permitted multiple material properties to be independently held constant to evaluate a single variable at a time. Independent control was accomplished by tuning the concentration of crosslinker to achieve an effectively constant stiffness for different HA hydrogel molecular weights and polymer concentrations. Specific formulations were thereby identified that enabled the molecular weight (76–1550 kDa), concentration (2%–10%), or stiffness (∼1–350 kPa) to be varied while the other two were held constant, a key technical achievement. The response of rat mesenchymal stem cells to varying molecular weight, concentration, and stiffness demonstrated consistent upregulation of osteocalcin gene expression. The methodology presented to achieve independent control of hydrogel parameters may potentially be adopted by others for alternative hydrogel polymers, cell types, or cell culture medium compositions to minimize confounding variables in experimental hydrogel designs.
Projected changes in early summer ridging and drought over the Central Plains
Authors: Cook Benjamin I , Williams A Park , Marvel Kate
Published: August 2022

Early summer (May–June–July; MJJ) droughts over the Central Plains are often caused by atmospheric ridging, but it is uncertain if these events will increase in frequency or if their influence on drought severity will change in a warming world. Here, we use tree-ring based reconstructions (1500–2020 CE) of MJJ ridging and 0–200 cm soil moisture with six CMIP6 model ensembles to investigate the response of Central Plains drought dynamics to a moderate warming scenario (SSP2-4.5). By the end of the 21st century (2071–2100), precipitation increases in most models during the preceding months (February–March–April), especially over the northern part of the Central Plains, while changes during MJJ are non-robust. By contrast, vapor pressure deficit increases strongly in all models, resulting in five of the six models projecting robust median soil moisture drying and all six models projecting more rapid seasonal soil moisture declines during the transition into the summer. Major ridging events increase in frequency in some models, and there is strong agreement across all models that when ridging events do occur, they will cause more severe soil moisture drought and seasonal drying at the end of the 21st century. The median multi-model response also indicates, by the end of the 21st century, that the Central Plains will experience a three-fold increase in the risk of drought events equivalent to the most extreme droughts of the last 500 years. Our results demonstrate that even moderate warming is likely to increase early summer soil moisture drought severity and risk over the Central Plains, even in the absence of robust precipitation declines, and that drought responses to major atmospheric ridging events will be significantly stronger.