bluuebunny/crossref_metadata_2025 huggingface dataset:
Space-charge-controlled field emission analysis of current conduction in amorphous and crystallized atomic-layer-deposited Al2O3 on GaN
Authors: Hiraiwa Atsushi , Horikawa Kiyotaka , Kawarada Hiroshi
Published: May 2021

As previously reported, postdeposition annealing at 800 °C and higher simultaneously crystallizes atomic-layer-deposited (ALD) Al2O3 films and reduces the current in Al/ALD-Al2O3/(0001) GaN capacitors by two orders of magnitude. This current reduction is caused by the enhancement of conduction band offset from 1.4 to 1.8 eV, as revealed by the space-charge-controlled field emission analysis. Selected area electron diffraction (SAED) patterns demonstrate that the crystallized films consist of twinned (111)-oriented cubic γ-Al2O3 with an epitaxial relation of Al2O3 ⟨01¯1⟩∥ GaN ⟨21¯1¯0⟩. The SAED patterns additionally include spots that are specific to triaxially tripled γ-Al2O3. The aforementioned epitaxy is due to the similarity of hexagonal close-packed sublattices between oxygen on a (111) γ-Al2O3 plane and nitrogen on a (0001) GaN plane. However, the hexagonal close-packed lattice constant of γ-Al2O3 is 12% smaller than that of GaN, necessitating domain matching epitaxy. The thickness of the interfacial transition layer caused by the large misfit is estimated to be thinner than four monolayers of oxygen sublattice, by using the methodology developed here. Based on these results, the effect of Al2O3 crystallinity on the characteristics of Al2O3/GaN capacitors, such as conduction current, dielectric breakdown, interface states, and bias instability, was comprehensively captured. According to x-ray diffraction analyses, Al2O3 films crystallize at 700 °C, which is ∼100 °C lower than the threshold temperature estimated by transmission electron microscope observations. This difference was possibly caused by locally crystallized Al2O3 films, as confirmed by the slightly reduced current. These findings form a basis for improving ALD-Al2O3 films as gate insulator.
Experimental demonstration of a reconfigurable acoustic second-order topological insulator using condensed soda cans array
Authors: Yue Zichong , Liao Danwei , Zhang Zhiwang , Xiong Wei , Cheng Ying , Liu Xiaojun
Published: May 2021

Traditional topological insulators support the topologically protected boundary states that are one dimension lower than the system itself. Recently, higher-order topological insulators have received increasing attention in the field of acoustic wave manipulation due to their unique bulk-boundary correspondence principle, hosting both gapped edge states and in-gap corner states simultaneously. However, for most of the topological acoustic systems, the lack of reconfigurability and the inevitable outer trivial regions with considerable thickness restrict the potential applications of acoustic topological insulators. Here, we experimentally demonstrate a reconfigurable condensed acoustic second-order topological insulator in free space by using subwavelength soda cans whose side length is significantly reduced to 1.89 times of the corresponding wavelength. The topological nontrivial phase is introduced through tunably modulating the interval between cans. Without the typically required outer trivial regions, we observe the topological corner states at the corner of the finite structures in both simulations and experiments. Furthermore, the robustness against the defects induced by dislocations and deformations is discussed. We foresee that the proposal may facilitate the application potentials of topological acoustics in low-frequency sound manipulations.
Effect of substrate preparation on the growth of lead-free piezoelectric (K0.5Na0.5)NbO3 on Pt(111)
Authors: Groppi C. , Mondonico L. , Maspero F. , Rinaldi C. , Asa M. , Bertacco R.
Published: May 2021

Lead-free piezoceramics aiming at replacing the market-dominant Pb(ZrxTi1−x)O3 have been extensively researched for more than a decade worldwide due to the toxicity of lead. In this context, (K0.5Na0.5)NbO3 (KNN) triggered the attention of the scientific community thanks to its bulk record piezoelectric coefficient combined with high critical temperature, which make it a good candidate for applications. In this paper, (001)-oriented KNN thin films grown by pulsed laser deposition on Pt(111)/TiO2/SiO2/Si substrates are investigated. We highlight the relevance of the template substrate in determining the structure of the film. Developing a suitable treatment for the Pt substrate is of great importance to film morphologic and topographic quality and to electric, ferroelectric, and piezoelectric properties. From local characterization of piezoelectric properties, we find a piezoelectric coefficient d33 of about 80 pm/V, comparable to the highest values reported for state-of-the-art undoped KNN thin films. Finally, electrical characterization of fabricated micro-capacitors allows the investigation of dielectric performance and shows remanent ferroelectric polarization over microscopic areas, thus paving the way to the integration of these KNN films in microfabricated actuator devices.
Fire – the influence of an extreme habitat disturbance on a threatened population of Desmoulin’s whorl snail: a case study from Poland
Authors: Lipińska Anna M. , Ćmiel Adam M. , Kwaśna Dorota
Published: May 2021

Terrestrial gastropods are keenly sensitive to changes in vegetation structure owing to their dependence on moisture. For this reason, low survivorship and recolonisation are to be expected after a fire. The fire described in this paper probably started as a result of the deliberate spring burning of vegetation that got out of control. Analysis of the data collected immediately after the fire does not reveal significant differences in the numbers of snails between habitats. This suggests that there are no refugia for this population: no vegetation-related refugium was confirmed. After the fire, snail numbers were found to have crashed, but the slight increase during the season could have been an indication of incipient recovery. Because the population of this species was consistently small, no differences in survivorship between habitats, regardless of their type, were discernible. The effects of the fire on this population in the River Nida Inland Delta were devastating: while it did survive the fire, its numbers fell sharply, by as much as two orders of magnitude.
Noncanonical protein kinase A activation by oligomerization of regulatory subunits as revealed by inherited Carney complex mutations
Authors: Jafari Naeimeh , Del Rio Jason , Akimoto Madoka , Byun Jung Ah , Boulton Stephen , Moleschi Kody , Alsayyed Yousif , Swanson Pascale , Huang Jinfeng , Martinez Pomier Karla , Lee Chi , Wu Jian , Taylor Susan S. , Melacini Giuseppe
Published: May 2021

Significance

Autosomal dominant mutations in one of the most ubiquitous isoforms of the inhibitory subunit (R1α) of protein kinase A (PKA) are linked to a generalized tumor predisposition, referred to as Carney complex (CNC). The molecular phenotype of CNC mutants is PKA overactivation. However, explaining PKA overactivation remains an unmet challenge for some of the most harmful CNC mutants, which are expressed and exhibit significantly reduced affinity for the cAMP activator but not for the PKA catalytic subunit (C). Here, we address this challenge by proposing a mechanism of PKA activation, distinct from the classical cAMP-dependent dissociation of the R
2
:C
2
complex and based on oligomerization of R1α into assemblies, which are incompetent to inhibit PKA C.
Phase space transport in the interaction between shocks and plasma turbulence
Authors: Trotta Domenico , Valentini Francesco , Burgess David , Servidio Sergio
Published: May 2021

Significance

Shocks and turbulence are spectacular, ubiquitous phenomena. In this work, we investigate, by kinetic simulations, the interaction between a supercritical shock and fully developed plasma turbulence. We demonstrate how turbulence dramatically changes the phase space transport due to a complex interaction. Two main findings are presented: 1) a paradigm for modeling the shocks, including a natural interaction with surrounding turbulence, and 2) an analysis method, based on coarse-grained kinetic equations, able to characterize (and simplify) the transport processes. These results are relevant for a variety of systems, ranging from the Earth’s bow shock interacting with solar wind turbulence to supernovae explosions propagating through the interstellar turbulent medium.
Parrhesia, orthodoxy, and irony
Authors: Chu Joon-Beom
Published: May 2021

This research applies Foucault’s framework ofparrhesiaor “truth-telling” to analyze the twelve Republican Party’s Presidential debates in 2015–2016, culminating in the nomination of Donald Trump as the party’s Presidential candidate. Using discourse and conversation analytical methods, it explores how the three main debate competitors constructed three different narratives of truth: Donald Trump’s “parrhesiastic truth;” Marco Rubio’s “orthodox truth;” and Ted Cruz’s “ironic truth” produced by combining features of the former two. Key findings of this research are that different narratives of truth compete during political elections, and that their public resonance, or lack thereof, is historically contingent, based on shifting public attitudes towards institutional power. Politicians such as Ted Cruz who attempt to emulateparrhesiarisk fracturing their personal and political voices, resulting in incoherence and silence on the public stage.
Critique de Saiz-Sánchez (2020): Les marqueurs d’accord et de désaccord du français et de l’espagnol. Étude diachronique XIe-XVIIIe siècle
Authors: Rodríguez Somolinos Amalia
Published: May 2021

Review of Marta Saiz-Sánchez (2020). Les marqueurs d’accord et de désaccord du français et de l’espagnol. Étude diachronique XIe-XVIIIe siècle. Berne : Peter Lang. 460 p. L’ouvrage que nous présentons est une étude exhaustive sur le fonctionnement des marqueurs d’accord et de désaccord oui, non et si du français, et sí et no de l’espagnol, mais également des structures anciennes qui en sont à l’origine, comme oïl, si feray ge ou non est, pour le français médiéval, et si faze ou sy haré, pour l’espagnol médiéval.
Euschistus heros (Neotropical brown stink bug).
Authors: Ziller Silvia Renate
Published: May 2021

Euschistus heros feeds on several crop plants, especially soyabean. Although it is known as the Neotropical stink bug, there is no clear information about its native range. E. heros is not included in any lists of Euschistus species indigenous to South America (e.g., Grazia, 1987; Martins and Campos, 2006) so it is presumed to have been introduced to the region. There is no reference to impacts or invasiveness in natural areas, only on cultivated crops. Crop losses are mainly caused by the injection of saliva containing tissue-destroying enzymes resulting in damage to the fruits and seeds, and secondarily by physical damage. Although adapted to warmer climates, E. heros has recently spread to southern Brazil and Argentina through the trade in soyabean, and is establishing in new areas, probably favoured by climate change. Road transportation of soyabean is one of the main pathways of introduction of this pest to new areas as the insects can live in crop residues. Most of the published information on E. heros is from Brazil, where the species is a serious pest in soyabean cultivation. Intensive chemical control has been used to reduce economic losses in plantations and may have detrimental effects on the environment. Potential biological control agents have been identified, and insect resistant genotypes have been developed.
Poly(ADP-ribose) binding and macroH2A mediate recruitment and functions of KDM5A at DNA lesions
Authors: Kumbhar Ramhari , Sanchez Anthony , Perren Jullian , Gong Fade , Corujo David , Medina Frank , Devanathan Sravan K. , Xhemalce Blerta , Matouschek Andreas , Buschbeck Marcus , Buck-Koehntop Bethany A. , Miller Kyle M.
Published: May 2021

The histone demethylase KDM5A erases histone H3 lysine 4 methylation, which is involved in transcription and DNA damage responses (DDRs). While DDR functions of KDM5A have been identified, how KDM5A recognizes DNA lesion sites within chromatin is unknown. Here, we identify two factors that act upstream of KDM5A to promote its association with DNA damage sites. We have identified a noncanonical poly(ADP-ribose) (PAR)–binding region unique to KDM5A. Loss of the PAR-binding region or treatment with PAR polymerase (PARP) inhibitors (PARPi’s) blocks KDM5A–PAR interactions and DNA repair functions of KDM5A. The histone variant macroH2A1.2 is also specifically required for KDM5A recruitment and function at DNA damage sites, including homology-directed repair of DNA double-strand breaks and repression of transcription at DNA breaks. Overall, this work reveals the importance of PAR binding and macroH2A1.2 in KDM5A recognition of DNA lesion sites that drive transcriptional and repair activities at DNA breaks within chromatin that are essential for maintaining genome integrity.
Measuring Time with Fossils: A Start-Up Problem in Scientific Practice
Authors: Dresow Max
Published: May 2021

This article is about a start-up problem in scientific practice. Specifically, it is about the problem of justifying paleontological correlation—the practice of using fossils to establish time relations among fossiliferous rocks. Paleontological correlation was the key to assembling a geological timescale during the nineteenth century and remains an important practice in stratigraphic geology to this day. Yet contrary to philosophical expectations, this practice lacked a robust theoretical justification during the first half of the nineteenth century. This article examines what this lack of justification amounted to, as well as how the method of paleontological correlation was justified in practice.
The Substantial Role of Weyl Symmetry in Deriving General Relativity from String Theory
Authors: Dougherty John
Published: May 2021

String theory reduces to general relativity in appropriate regimes. Huggett and Vistarini have given an account of this reduction that includes a deflationary thesis about symmetry: although the usual derivation of general relativity from string theory appeals to a premise about the theory’s symmetry, Huggett and Vistarini argue that this premise plays no logical role. In this article I disagree with their deflationary thesis and argue that their analysis is based on a popular but flawed conception of the interaction between symmetry and quantization. I argue that a better conception recognizes a distinction between ordinary, broken, and anomalous symmetries.
Explanatory Coherence and the Impossibility of Confirmation by Coherence
Authors: Poston Ted
Published: May 2021

The coherence of independent reports provides a strong reason to believe that the reports are true. This plausible claim has come under attack from recent work in Bayesian epistemology. This work shows that, under certain probabilistic conditions, coherence cannot increase the probability of the target claim. These theorems are taken to demonstrate that epistemic coherentism is untenable. To date no one has investigated how these results bear on different conceptions of coherence. I investigate this situation using Thagard’s ECHO model of explanatory coherence. Thagard’s ECHO model provides a natural representation of the evidential significance of multiple independent reports.
Understanding and Equivalent Reformulations
Authors: Hunt Josh
Published: May 2021

Reformulating a scientific theory often leads to a significantly different way of understanding the world. Nevertheless, accounts of both theoretical equivalence and scientific understanding have neglected this important aspect of scientific theorizing. This essay provides a positive account of how reformulation changes our understanding. My account simultaneously addresses a serious challenge facing existing accounts of scientific understanding. These accounts have failed to characterize understanding in a way that goes beyond the epistemology of scientific explanation. By focusing on cases in which we have differences in understanding without differences in explanation, I show that understanding does not reduce to explanation.
Reflexivity, Functional Reference, and Modularity: Alternative Targets for Language Origins
Authors: LaCroix Travis
Published: May 2021

Researchers of language origins typically try to explain how compositional communication might evolve to bridge the gap between animal communication and natural language. However, as an explanatory target, compositionality has been shown to be problematic for a gradualist approach to the evolution of language. In this article, I suggest that reflexivity provides an apt and plausible alternative target that does not succumb to the problems that compositionality faces. I further explain how protoreflexivity, which depends on functional reference, gives rise to complex communication systems via modular composition.
Ionization in intense laser fields beyond the electric dipole approximation: concepts, methods, achievements and future directions
Authors: Maurer J , Keller U
Published: May 2021

The electric dipole approximation is widely used in atomic, molecular and optical physics and is typically related to a regime for which the wavelength is much larger than the atomic structure. However, studies have shown that in strong laser fields another regime exists where the dipole approximation breaks down. During the ionization process in intense laser fields and at long wavelengths the photoelectrons can reach higher velocities such that the magnetic field component of the laser field becomes significant. The ionization dynamics and the final momentum of the electron is therefore modified by the entire Lorentz force. In contrast the magnetic field interaction is neglected in the dipole approximation. Rapid developments in laser technology and advancements in the accuracy of the measurements techniques have enabled the observation of the influence of such non-dipole effects on the final angular photoelectron momentum distributions. More recently the number of studies on ionization beyond the dipole approximation has increased significantly, providing more important insight into fundamental properties of ionization processes. For example we have shown that the final three dimensional photoelectron momentum spectra is significantly affected by the non-dipole drift with the parent–ion interaction, the linear multiphoton momentum transfer on a sub-cycle time scale and the sharing of the transferred linear photon momenta between the electron and the ion. In this article we present an overview of the underlying mechanisms and we review the experimental techniques and the achievements in this field. We focus on ionization in strong laser fields in the regime where the dipole approximation is not valid but a fully relativistic description is not required.
The role of O3 on the selective formation of nitrate and nitrite in plasma-treated water
Authors: Teng Yung-Hsin , Lin Yen-Ting , Wang Wei-Hsiang , Liao Ying-Hao
Published: May 2021

This study is to investigate the role of O3 on NO and NO2 oxidations to selective formations of NO2
− and NO3
− in plasma-treated water. Two plasma reactors, a surface dielectric-barrier discharge (DBD) and a coaxial DBD jet, are employed to water treatment with a working gas primarily consisting of N2 and O2. Results of surface DBD show that O3 first is increased with plasma treatment time, reaching a maximum, and then decreased. NO takes time to grow and the grow of NO is accompanied by O3 decrease. Formations of NO2
− and NO3
− are associated with gas-phase nitrogen oxides while the presence of O3 has a critical influence on a selective formation of NO2
− and NO3
−. The strong oxidation of O3 favors the formation of NO3
− while inhibits NO2
− formation. O3 serving as an inhibitor of NO2
− is confirmed with the DBD jet experiment where O3 is admixed in the downstream of the post discharge. O3 enhancement on NO3
− formation is demonstrated by exposing water to a synthetic NO gas with and without O3. In addition to O3, the presence of water vapor in the working gas, presumably facilitating formation of HNO2 and HNO3, greatly promotes NO2
− and NO3
− concentrations in solution. This is thought to be due to the stronger dissolution susceptibility and the relatively larger rate constant of HNO2 and HNO3 than those of N2O3 and N2O5. Finally, based on observations obtained here, a schematic roadmap of selective NO2
− and NO3
− formations is presented.
Weak crack identification of compressor impeller with hybrid methods of PNNs and SVD
Authors: Jiang Yongying , Wang Naige , Zhong Yongteng , Shao Liang
Published: May 2021

Damage to a compressor impeller can sometimes cause serious accidents, heavy casualties and property loss, etc. Therefore, it is necessary to conduct damage monitoring and identification for the compressor impeller. A damage identification method based on probabilistic neural networks (PNNs) with modal information fusion is proposed for a compressor impeller. The modal shape of the compressor impeller can be acquired by experimental modal analysis. Combining waveform capacity dimension, a singular value decomposition is applied to extract damage feature information from the system modal shape. The two damage indicators are fused by a multi-dimensional feature vector. Finally, a PNN model is constructed and used to identify structural damage. The experimental results indicate that the proposed method is effective in detecting damage to the compressor impeller.
Ab Initio modeling of Near-Edge EELS spectra for chemisorbed molecules
Authors: Jia Haili , Wang Canhui , Wang Chao , Clancy Paulette
Published: May 2021

Electron energy loss spectroscopy (EELS) has recently been applied to probe chemisorbed molecules on metal nanostructures, but a fundamental understanding of the correlation between these spectra and the electronic structures of the adsorbates has been limited. We report here on the insights afforded by time-dependent density functional theory to decipher the energy loss near edge structure (ELNES) of EELS spectra associated with chemisorption. These first-principles calculations simulate the ELNES-EELS spectra for chemisorbed CO on various facets of Au and Pt. Computational predictions of key signatures such as the ‘red shift’ and reductions in the peak intensity of the 2π* and 6σ* peaks, as compared to free CO in the gas phase, are validated in comparison to experimentally collected EELS spectra. These signatures are revealed to arise from changes in the electronic structure in terms of unoccupied density of states associated with the chemisorption process. They are consistent with a Blyholder model that incorporates donation and back-donation of electrons. They are also characteristic of the chemisorption process, such as the choice of metal, site of adsorption and the coverage and distribution of adsorbates. Our simulations thus provide guidelines for the use of ELNES-EELS to characterize the atomic structure and adsorption property of nanostructured surfaces and facilitate the development of advanced nanomaterials for catalytic applications.
Microscopy-based infrared spectroscopy as a tool to evaluate the influence of essential oil on the surface of loaded bilayered-nanoparticles
Authors: da Costa Ítalo Carvalho , Matos Robert Saraiva , de Azevedo Sidney Gomes , Costa Carlos Alberto Rodrigues , Sanches Edgar Aparecido , da Fonseca Filho Henrique Duarte
Published: May 2021

Increasing interest in nanoparticles of technological application has been improving their fabrication processes. The encapsulation of essential oils as bioactive compounds has proved to be an excellent alternative to the use of less environment friendly compounds. However, the difficulty of identifying their constitution and interaction with carrier agents have aroused scientific interest and a problem to overcome. Bilayer-based nanoparticles were developed using gelatin and poly-ε-caprolactone (PCL) aiming the encapsulation of Piper nigrum essential oil. based on atomic force microscopy images and dynamic light scattering analysis, the size of the unloaded and loaded nanoparticles was found around (194 ± 40) and (296 ± 54) nm, respectively. The spatial patterns revealed that the surface of nanoparticles presented different surface roughness, similar shapes and height distribution asymmetry, lower dominant spatial frequencies, and different spatial complexity. Traditional infrared spectroscopy allowed the identification of the nanoparticle outermost layer formed by the gelatin carrier, but microscopy-based infrared spectroscopy revealed a band at 1742 cm−1 related to the carbonyl stretching mode of PCL, as well as a band at 1557 cm−1 due to the amide II group from gelatin. The combination of microscopy and spectroscopy techniques proved to be an efficient alternative to quickly identify differences in chemical composition by evaluating different functional groups in bilayer PLC/gelatin nanoparticles of technological application.
Nanofluidic charged-coupled devices for controlled DNA transport and separation
Authors: Nouri Reza , Guan Weihua
Published: May 2021

Controlled molecular transport and separation is of significant importance in various applications. In this work, we presented a novel concept of nanofluidic molecular charge-coupled device (CCD) for controlled DNA transport and separation. By leveraging the unique field-effect coupling in nanofluidic systems, the nanofluidic molecular CCD aims to store charged biomolecules such as DNAs in discrete regions in nanochannels and transfer and separate these biomolecules as a charge packet in a bucket brigade fashion. We developed a quantitative model to capture the impact of nanochannel surface charge, gating voltage and frequency, molecule diffusivity, and gating electrode geometry on the transport and separation efficiency. We studied the synergistic effects of these factors to guide the device design and optimize the DNA transport and separation in a nanofluidic CCD. The findings in this study provided insight into the rational design and implementation of the nanofluidic molecular CCD.
A multi-channel optical fibre-based smartphone spectrophotometer for measuring the spectra of LED colours
Authors: Puttharugsa Chokchai , Srikhirin Toemsak , Pipatpanukul Chinnawut , Houngkamhang Nongluck
Published: May 2021

This paper demonstrates the use of a smartphone as a low-cost multi-channel optical fibre spectrophotometer suitable for physics laboratory classes. A custom-designed cradle and structure support were fabricated using 3D printing. The plastic optical fibres were arranged and inserted into the hole of the cradle to guide the light to the rear camera of the smartphone. Here, we describe the multi-channel optical fibre-based smartphone spectrophotometer for measuring the spectra of different LED colours.
Water-responsive tough 1D hydrogel with programmable deformations for actuators and chemical sensors
Authors: Kim Sang Heon , Jeong Jae Hwan , Shim Hyeonbo , Woo Hee-Chul , Imani Kusuma Betha Cahaya , Yoon Jinhwan , Jeong Jae Hyun , Kim Mun Ho
Published: May 2021

To utilize water-responsive hydrogels in biomedical devices and soft robotics, hydrogels with high response speed and good mechanical properties are required. However, fabrication of such hydrogels remains challenging. In this study, a facile method for producing a one-dimensional (1D) hydrogel with water-responsive programmable deformations was developed. A tough hydrogel fiber with an interpenetrating polymer network based on a biopolymer was synthesized using a template-directed method. A 1D hydrogel that shrinks quickly in contact with water was fabricated by simply stretching and drying the hydrogel fiber under ambient conditions. The fabricated 1D hydrogel exhibited excellent mechanical properties, accurately controlled and programmable deformations, and an extraordinarily high degree of deformation with dimensional changes greater than 300%. Based on such 1D hydrogels, one-way soft actuators, which can be bent or can lift a weight when exposed to water, and a chemical sensing platform, which can detect ethanol in a water–ethanol mixture, were developed.
Composable security for practical quantum key distribution with two way classical communication
Authors: Jiang Cong , Hu Xiao-Long , Yu Zong-Wen , Wang Xiang-Bin
Published: May 2021

We present a theory for the composable security of sending-or-not-sending (SNS) protocol of twin field quantum key distribution (TF-QKD). We present methods to strictly calculate the finite-key effects in QKD with error rejection through two-way classical communication (TWCC) for SNS TF-QKD protocol. Unlike the normal QKD without TWCC, here the probability of tagging or untagging for each two-bit random group is not independent. We rigorously solve this problem by imagining a virtual set of bits where every bit is independent and identical. With explicit formulas, we show that simply applying Chernoff bound in the calculation gives correct key rate, but the failure probability changes a little bit. We calculate the key rate with strict bounds and security, and obtain key rates by far breaking the PLOB (Pirandola, Laurenza, Ottaviani, and Banchi) bound with composable security.
Polarization dependent beaming properties of a plasmonic lattice laser
Authors: Asamoah Benjamin O , Partanen Henri , Mohamed Sughra , Heikkinen Janne , Halder Atri , Koivurova Matias , Nečada Marek , Setälä Tero , Turunen Jari , Friberg Ari T , Hakala Tommi K
Published: May 2021

We study beaming properties of laser light produced by a plasmonic lattice overlaid with organic fluorescent molecules. The crossover from spontaneous emission regime to stimulated emission regime is observed in response to increasing pump fluence. This transition is accompanied by a strong reduction of beam divergence and emission linewidth due to increased degree of spatial and temporal coherence, respectively. The feedback for the lasing signal is shown to be mainly one-dimensional due to the dipolar nature of the surface lattice resonance. Consequently, the beaming properties along x and y directions are drastically different. From the measurements, we obtain the M
2 value along both principal directions of the square lattice as a function of the pump fluence. Our work provides the first detailed analysis of the beam quality in plasmonic lattice lasers and reveals the underlying physical origin of the observed strong polarization dependent asymmetry of the lasing signal.
Decoherence dynamics of a charged particle within a non-demolition type interaction in non-commutative phase-space
Authors: Germain Yiande Deuto , Armel Azangue Koumetio , Tene Alain Giresse , Isofa Nsangou , Tchoffo Martin
Published: May 2021

This paper studies decoherence without dissipation of charged magneto-oscillator in the framework of quantum non-demolition type interaction in non-commutative phase-space. The master equation is derived considering the non-commutativity effects of a bath of harmonic oscillators to study the dynamics of such a system, and its possible exact solution is presented. By analyzing this solution, it turns out that the process involving decoherence without energy dissipation can be observed explicitly. In addition, the decoherence factor and the measure of coherence via linear entropy dynamic are deduced for two types of reservoir, namely the ohmic and super-ohmic reservoirs at low and high temperature limits. Numerical results obtained show that the coherence is better preserved in the system when non-commutativity effects are taken into account at low temperature, while the inverse phenomenon is observed at high temperature. Moreover, by kindly adjusting the non-commutative parameters, it is possible to improve the coherence time scale of the system. Another interesting result can be observed from the system’s coherence time scale, which is very sensitive to the magnetic field and thus adding to non-commutative parameters, it may be useful to control decoherence in the system.
New analytical solutions for the inextensible Heisenberg ferromagnetic flow and solitonic magnetic flux surfaces in the binormal direction
Authors: Körpınar Talat , Demirkol Rıdvan Cem , Körpınar Zeliha
Published: May 2021

Maxwellian electromagnetism describes the wave features of the light and related subjects. Its original formulation was established 150 years ago. One of the four Maxwell’s equations is Gauss’s law, which states significant facts regarding magnetic flux through surfaces. It was also observed that optical media provides surface electromagnetism around 60 years ago. This observation leads to improve new techniques on nano-photonics, metamaterials, and plasmonics. The goal of this manuscript is to suggest novel accurate and local conditions for defining magnetic flux surfaces for the inextensible Heisenberg ferromagnetic flow in the binormal direction. The theoretical accuracy of the methodology is verified through the evolution of magnetic vector fields and the anti-symmetric Lorentz force field operator. On the other hand, the numerical accuracy and efficiency is developed in detail by considering the conformable fractional derivative method when these fields are transformed under the traveling wave hypothesis.
Gravitational-wave detector networks: standard sirens on cosmology and modified gravity theory
Authors: Yang Tao
Published: May 2021

We construct the catalogues of standard sirens (StS) based on the future gravitational wave (GW) detector networks, i.e., the second-generation ground-based advanced LIGO+advanced Virgo+KAGRA+LIGO-India (HLVKI), the third-generation ground-based Einstein Telescope+two Cosmic Explorer (ET+2CE), and the space-based LISA+Taiji. From the corresponding electromagnetic (EM) counterpart detectors for each networks, we sample the joint GW+EM detections from the probability to construct the Hubble diagram of standard sirens for 10 years detections of HLVKI, 5 years detections of ET+2CE, and 5 years of detections of LISA+Taiji, which we estimate would be available and released in the 2030s. Thus we construct a combined Hubble diagram from these ground and spaced-based detector networks to explore the expansion history of our Universe from redshift 0 to 7. We give a conservative and realistic estimation of the catalogue and Hubble diagram of GW standard sirens and their potential on studying cosmology and modified gravity theory in the 2030s. We adopt two strategies for the forecasts. One is the traditional model-fitting Markov-Chain Monte-Carlo method (MCMC). The results show that the combined StS alone can constrain the Hubble constant at the precision level of 0.34%, 1.76 times more tightly than the current most precise measurement from Planck+BAO+Pantheon. The joint StS with current EM experiments will improve the constraints of cosmological parameters significantly. The modified gravity theory can be constrained with 0.46% error from the GW propagation. In the second strategy, we use the machine-learning nonparametric reconstruction techniques, i.e., the Gaussian process (GP) with the Artificial Neural Networks (ANN) as a comparison. GP reconstructions can give comparable results with MCMC. We anticipate more works and research on these topics.
Effective theory of inflationary magnetogenesis and constraints on reheating
Authors: Maity Debaprasad , Pal Sourav , Paul Tanmoy
Published: May 2021

Effective theory framework based on symmetry has recently
gained widespread interest in the field of cosmology. In this
paper, we apply the same idea on the genesis of the primordial
magnetic field and its evolution throughout the cosmological
universe. Given the broken time-diffeomorphism symmetry by the
cosmological background, we considered the most general Lagrangian
of electromagnetic and metric fluctuation up to second order, which
naturally breaks conformal symmetry in the electromagnetic (EM)
sector. We also include parity violation in the electromagnetic
sector with the motivation that has potential observational
significance. In such a set-up, we explore the evolution of EM,
scalar, and tensor perturbations considering different observational
constraints. In our analysis we emphasize the role played by the
intermediate reheating phase which has got limited interest in all
the previous studies. Assuming the vanishing electrical conductivity
during the entire period of reheating, the well-known Faraday
electromagnetic induction has been shown to play a crucial role in
enhancing the strength of the present-day magnetic field. We show
how such physical effects combined with the PLANCK and the large
scale magnetic field observation makes a large class of models
viable and severely restricts the reheating equation of state
parameter within a very narrow range of 0.01 < ωeff < 0.27, which is nearly independent of reheating scenarios we
have considered.
Searching for axion-like particle decay in the near-infrared background: an updated analysis
Authors: Caputo Andrea , Vittino Andrea , Fornengo Nicolao , Regis Marco , Taoso Marco
Published: May 2021

The extragalactic background light is comprised of the cumulative radiation from all galaxies across the history of the universe. The angular power spectrum of the anisotropies of such a background at near-infrared (IR) frequencies lacks of a complete understanding and shows a robust excess which cannot be easily explained with known sources. Dark matter in the form of axion-like particles (ALPs) with a mass around the electronvolt will decay into two photons with wavelengths in the near-IR band, possibly contributing to the background intensity. We compute the near-IR background angular power spectrum including emissions from galaxies, as well as the contributions from the intra-halo light and ALP decay, and compare it to measurements from the Hubble Space Telescope and Spitzer. We find that the preferred values for the ALP mass and ALP-photon coupling to explain the excess are in tension with star cooling data and observations of dwarf spheroidal galaxies.
Reconstruction of reionization history through dispersion measurements of fast radio bursts
Authors: Dai Ji-Ping , Xia Jun-Qing
Published: May 2021

In this paper, we study the evolution of the ionization
fraction x
e(z) during the epoch of reionization by using the
dispersion measurements (DMs) of fast radio bursts (FRBs). Different
from the previous studies, here we turn to consider the large-scale
clustering information of observed DMs of FRB catalog, which only
needs the rough redshift distribution, instead of the exact redshift
information of each FRB. Firstly, we consider the instantaneous
“tanh” model for x
e(z) and find that including the
auto-correlation information of the mock catalog, about 104 FRBs
with the intrinsic DM scatter of 100 pc/cm3 spanning 20% of
all sky, could significantly improve the constraint on the width
Δz of the model, when comparing with that from the CMB data
alone. The evolution shape of the ionization fraction will be
tightly narrowed, namely the duration of the epoch of reionization
has been shrunk, z
dur < 2.24 (95% C.L.). Furthermore, we
also use another redshift-asymmetric reionization model and obtain
that the FRB mock catalog could measure the ionization fraction at
z = 6 precisely with the 1σ error Δ x
e (z = 6) = 0.012,
which means that the large-scale clustering information of observed
DMs of FRB catalog is very sensitive to the ionization fraction of
the end of reionization epoch. We conclude that the observation of
high-redshift FRBs could be a complementary probe to study the
reionization history in the future.
The First Photometric Investigation and Spectroscopic Analysis of Two Contact Binaries: ASAS J124343+1531.7 and LINEAR 2323566
Authors: Xia Qiqi , Michel Raul , Li Kai , Higuera Jesus
Published: May 2021

The multi-color passband CCD light curves of ASAS J124343+1531.7 and LINEAR 2323566 were first obtained by the 0.84 m Ritchey–Chrétien telescope with follow up observations by the WIYN 0.90 m Cassegrain telescope. The data from the Transiting Exoplanet Survey Satellite of ASAS J124343+1531.7 was also applied for subsequent analysis. By analyzing the data through the W-D program, their mass ratios and fill-out factors were determined as 3.758, 1.438 and 31.8%, 14.9%, respectively. ASAS J124343+1531.7 is a W-subtype median contact binary, while LINEAR 2323566 is a W-subtype shallow contact binary, and the asymmetric light curves prove that they both have the O’Connell effect, which is generally explained by magnetic activity. The equivalent widths of H
α
lines were calculated, which show they certainly have magnetic activity. Moreover, LINEAR 2323566 has a stronger magnetic activity. The analysis of orbital period changes shows that ASAS J124343+1531.7 has a trend of secular period increase, which is generally explained by the mass transfer from the less massive to the more massive star. According to the estimated absolute parameters, their evolutionary states are discussed. The two components of ASAS J124343+1531.7 are both main sequence stars. While for LINEAR 2323566, the more massive star is a main sequence star, the less massive star has evolved out of main sequence and is over-luminous and over-sized.
Selection of optimal parameters of technological modes for the synthesis of polymer composite materials based on verified mathematical models
Authors: Markov A V , Oreshina O A
Published: May 2021

In the modern realities of creating structural elements for various purposes, polymer composite materials are widely used. These materials are used in almost all industries, from aerospace, shipbuilding, automotive, and ending with consumer goods. The article shows the need to develop mathematical models that reflect the relationship between mechanical properties and parameters of technological modes for the synthesis of polymer composite materials, to select the optimal parameters of the technological mode of their synthesis. The article discusses the optimization of a group of mechanical properties described by mathematical models built on the basis of a full factorial experiment, in order to obtain the optimal values of the parameters of the technological modes of synthesis of a polymer composite material based on heat-resistant low-molecular-weight synthetic rubber with the addition of ferric iron oxide as a filler. The research method is optimization by the method of successive concessions. Computer experiments have been carried out to optimize the parameters of technological modes for the synthesis of materials. The performed calculations were checked with experimental data, the adequacy of the obtained models was checked.
Methods for measuring the reflection coefficient of radio waves
Authors: Samoylov A G , Samoylov S A
Published: May 2021

Methods for measuring the reflection coefficient of non-ionized electromagnetic radiation from sheet materials are considered. Horn antennas with square apertures were used for measurements. The maximum dimensions of the irradiation spot are determined depending on the distance to the irradiating horn antenna for different frequency ranges. Two methods of measuring the reflection coefficient of radio waves from sheet materials are described. The first method is based on the use of two antennas for irradiating the material and for receiving the reflected signal. The second method is based on the use of a measuring line. In this case, one antenna is used. A measuring installation was made.
Method of manufacturing reinforced concrete floor slabs using non-removable void formers
Authors: Pushkarev B A , Burenina N B
Published: May 2021

The article provides a critical analysis of the work on the manufacture of monolithic reinforced concrete, relying on the contour, hollow floor slabs using box-shaped, spherical and tubular hollow-formers. The paper proposes a method of manufacturing monolithic reinforced concrete hollow floor slabs based on the contour using circular tubular polyethylene cardboard holders of rectangular or square shape in plan. The subject of the research is a method of continuous production of reinforced concrete floor slabs with round voids based on the contour using non-removable void formers, their technical and economic efficiency of solutions to reduce the weight of monolithic floor slabs by reducing the resources for their production. The technical and economic feasibility of manufacturing monolithic reinforced concrete floor slabs based on the contour with the use of non-retrievable void formers from round pipes of square and rectangular shape in plan has been substantiated. Materials for the manufacture of void former are proposed. The technical result has been determined - the maximum weight reduction of the proposed hollow core slabs compared to solid slabs.
Generalized functions in non-linear thermal conductivity problem for two-layer structure with heat source
Authors: Mikheeva G V
Published: May 2021

Based on the generalized functions theory an exact analytical solution to the stationary non-linear problem of thermal conductivity for two-layer plate with heat sources for the asymmetrical Newton’s limiting conditions. Dependence of thermal conductivity factors of each layer on the temperature was assumed to be linear. The problem for a two-layer structure, using the Heaviside asymmetric unit function, is normalized to a single-layer one with piecewise homogeneous (discontinuous) properties of the medium. The advantage of this method for obtaining analytical solutions is that there is no need to directly fulfill the conjugation conditions at the layers’ contact points, since, thanks to the use of the Heaviside function, they are included in the generalized differential equation of the boundary value problem and are fulfilled in the process of obtaining its solution. A specific example of calculating the temperature state of a two-layer plate is provided.
Testing of thin-walled cylindrical shells made of steel 45 in solving the problem of stability
Authors: Cheremnykh S V
Published: May 2021

The theory of shell stability beyond the elastic limit is considered when studying the issue of testing, diagnostics and quality control of materials made of steel shells of round cylindrical cross-section. Since, depending on the history of the loading process of an elastic-plastic system, its final deformation corresponding to the same external load is different, by studying the inelastic stability problems should proceed from the analysis of simple combined loading processes that lead to different critical deformations. Not only the question of the loading history, which leads to the minimum value of critical loads, but also the question of choosing and implementing such a loading history of a given system, which gives it the maximum value of the stability limit and the load-bearing capacity of the material, is solved. Innovative methods are proposed for solving the problem of shell stability in tests of complex loading of steel cylindrical shells by internal pressure, compression and torsion in the direction of structural mechanics and mechanics of deformable solids, implemented on an experimental complex. The obtained results allow us to determine the loss of stability of the material beyond the elastic limit with a sufficient degree of accuracy for a given cross-section and the loading trajectory of a cylindrical thin-walled shell made of steel 45, while the correctness of the obtained results is justified experimentally.