bluuebunny/crossref_metadata_2025 huggingface dataset:
Self-bias voltage formation and charged particle dynamics in multi-frequency capacitively coupled plasmas
Authors: Masheyeva R. U. , Dzhumagulova K. N. , Myrzaly M. , Schulze J. , Donkó Z.
Published: July 2021

In this work, we analyze the creation of the discharge asymmetry and the concomitant formation of the DC self-bias voltage in capacitively coupled radio frequency plasmas driven by multi-frequency waveforms as a function of the electrode surface characteristics. For the latter, we consider and vary the coefficients that characterize the elastic reflection of electrons from the surfaces and the ion-induced secondary electron yield. Our investigations are based on particle-in-cell/Monte Carlo collision simulations of the plasma and on a model that aids the understanding of the computational results. Electron reflection from the electrodes is found to slightly affect the discharge asymmetry in the presence of multi-frequency excitation, whereas secondary electrons cause distinct changes to the asymmetry of the plasma as a function of the phase angle between the harmonics of the driving voltage waveform and as a function the number of these harmonics.
Bandgap bowing parameter and alloy fluctuations for β-(AlxGa1−x)2O3 alloys for x ≤ 0.35 determined from low temperature optical reflectivity
Authors: Bhattacharjee Jayanta , Ghosh Sahadeb , Pokhriyal Preeti , Gangwar Rashmi , Dutt Rajeev , Sagdeo Archna , Tiwari Pragya , Singh S. D.
Published: July 2021

A bandgap bowing parameter of 0.4 ± 0.2 eV for β-(AlxGa1−x)2O3 alloys, with Al compositions (x) up to 0.35, has been determined from the bandgap obtained from low temperature optical reflectivity, which suppresses the effect of electron–phonon interaction on the bandgap. A length scale of inhomogeneity of 0.21 ± 0.03 times of the electron–hole mean free path length has been estimated for β-(AlxGa1−x)2O3 alloys. The unit cell of β-(AlxGa1−x)2O3 alloys compresses, and the lattice parameters vary linearly with Al substitution. Our results provide insight into bandgap engineering and alloy disorder for β-(AlxGa1−x)2O3 alloys, which are an important material system for applications in deep ultraviolet opto-electronic devices.
Understanding the evolution of liquid and solid microjets from grooved Sn and Cu samples using radiography
Authors: Bober David B. , Mackay Kyle K. , Akin Minta C. , Najjar Fady M.
Published: July 2021

Experiments were performed on grooved Sn and Cu samples to study the temporal evolution of microjets. Jets were generated by the impact of gun-launched flyer plates against the back of grooved targets made from either Cu or Sn (groove depth of ∼250 μm). The Hugoniot states in the various Sn targets encompassed conditions where solid phases are maintained throughout (7 and 16 GPa) and also conditions where melting occurs upon the release of compression (25 and 34 GPa); the transition occurs near a Hugoniot pressure of 23 GPa. Cu targets at 27 and 56 GPa provide comparisons in which the jets move at similar speeds but remain solid. In all cases, the spatial distribution of mass within the microjets was measured using high-speed synchrotron radiography. The result is a time history of the jet thickness profile from which quantities like total jet mass and jet velocity can be derived. In both the solid and liquid states, we generally observe that an increase in the shock strength leads to an increase in jet mass. However, this trend breaks down for Hugoniot states near the transition from continuously solid to melted-on-release. This is evidenced by the observation that there was no difference in the rate of mass flow in Sn jets at 16 and 25 GPa, while similar pressure jumps on either side of this range caused substantial changes in the jet mass. This contrasts with the behavior of smaller polishing defects that were present on the same samples (∼1 μm deep). From these, no ejecta mass was detected below the melt boundary, but obvious microjets were generated once melting occurred. This indicates that crossing the bulk melt-on-release threshold can alternately promote or inhibit the flow of mass into microjets based on the amplitude of the initial perturbation.
Structural origin of thermal shrinkage in soda-lime silicate glass below the glass transition temperature: A theoretical investigation by microsecond timescale molecular dynamics simulations
Authors: Shimizu Masahiro , Murota Teppei , Urata Shingo , Takato Yoichi , Hamada Yuya , Koike Akio , Shimotsuma Yasuhiko , Fujita Koji , Miura Kiyotaka
Published: July 2021

Microscopic dynamical features in the relaxation of glass structures are one of the most important unsolved problems in condensed matter physics. Although the structural relaxation processes in the vicinity of glass transition temperature are phenomenologically expressed by the Kohlrausch–Williams–Watts function and the relaxation time can be successfully interpreted by Adam–Gibbs theory and/or Narayanaswamy’s model, the atomic rearrangement, which is the origin of the volume change, and its driving force have not been elucidated. Using the microsecond time-scale molecular dynamics simulations, this study provides insights to quantitatively determine the origin of the thermal shrinkage below Tg in a soda-lime silicate glass. We found that during annealing below Tg, Na ions penetrate into the six-membered silicate rings, which remedies the acute O–O–O angles of the energetically unstable rings. The ring structure change makes the space to possess the cation inside the rings, but the ring volume is eventually reduced, which results in thermal shrinkage of the soda-lime silica glass. In conclusion, the dynamical structural relaxation due to the cation displacement evokes the overall volume relaxation at low temperature in the glassy material.
Dynamic imprint recovery as an origin of the pulse width dependence of retention in Hf0.5Zr0.5O2-based capacitors
Authors: Chernikova Anna G. , Markeev Andrey M.
Published: July 2021

Retention of the storing polarization state at elevated temperatures (typically 85–105 °C) as well as the ability to rewrite and subsequently read it are an essential property of usable HfO2-based ferroelectrics for ferroelectric random access memory implementation. This work shows that retention loss in TiN/Hf0.5Zr0.5O2 (HZO)/TiN capacitors is highly dependent on the duration of pulses that are used for measurements, i.e., there is better retention of the same state (SS), new same state (NSS), and opposite state (OS) for longer pulses. The root cause of this phenomenon is the dynamic recovery of the imprint, which happens during the first long SS measurement. This may be due to the fast re-injection of charges injected from the electrode and trapped in the HZO during storage at elevated temperatures. Such dynamic imprint recovery underlies the best NSS behavior compared to other states and may affect the worst retention loss of the OS.
Enhanced thermoelectric performance in K0.87RhO2 thin films induced by changing ambient gases during pulsed laser deposition
Authors: Luo Wenhao , Li Liangjie , Yao Yingbang , Luo Bing , Zhang Fuzeng , Wang Tingting
Published: July 2021

K0.87RhO2 thin films were prepared by pulsed laser deposition on fused silica substrates under different ambient gases. Besides the usual forming gas for oxides (i.e., O2), N2, Ar, mixture of O2 + N2, mixture of O2 + Ar, and vacuum were used during deposition. Although the crystal structure remained the same for all films, their electrical and thermoelectric properties were modified significantly depending on the ambient gases. Compared with the film deposited under O2, the film deposited under N2 exhibits electrical resistances one order of magnitude smaller, while the film prepared in N2 + O2 shows 50% enhancement in Seebeck coefficients. Moreover, the thermoelectric power factor was enhanced more than 100% as the ambient gas changed to Ar. Origins of such improvements in thermoelectric performance were discussed from the point of view of crystal defects, such as oxygen vacancies. Our results suggest an efficient way to modify the performance of K0.87RhO2 thermoelectric materials.
Elastic instabilities between two cylinders confined in a channel
Authors: Kumar Manish , Ardekani Arezoo M.
Published: July 2021

Polymeric flow through porous media is relevant in industrial applications, such as enhanced oil recovery, microbial mining, and groundwater remediation. Biological processes, such as drug delivery and the transport of cells and particles in the body, also depend on the viscoelastic flow through the porous matrix. Large elastic stresses induced due to confined geometries can lead to elastic instability for the viscoelastic fluid flow through porous media. We have numerically studied viscoelastic flow through a channel having two closely placed cylinders to investigate pore scale elastic instabilities. We have discovered three distinct flow states in the region between the cylinders. These flow states are closely coupled with the topology of the polymeric stress field. The transition between the flow states can be identified with two critical Weissenberg numbers (Wicr1 and Wicr2), where the Weissenberg number (Wi) is the ratio of elastic to viscous forces. At Wi<Wicr1, the flow is stable, symmetric, and eddy free. For Wicr1<WiWicr2, the eddy disappears and the flow around the cylinders becomes asymmetric. We have quantified the flow asymmetry around the cylinders for different flow rates and fluid rheology. We have also studied the effect of the cylinders' diameter and separation on the eddies' size (Wicr1<WiWicr2). We have also investigated the effect of fluid rheology and cylinders' diameter and separation on the value of critical Weissenberg numbers.
Modulate the work function of Nb2CTx MXene as the hole transport layer for perovskite solar cells
Authors: Zhang Jiankai , Huang Chengwen , Yu Huangzhong
Published: July 2021

The hole transport layer (HTL) in perovskite solar cells (PVSCs) plays an important role in determining the crystallization of a perovskite film and holes transfer efficiency at the perovskite/HTL interface. Herein, the Nb2CTx Mxene with excellent photoelectric properties was prepared and utilized as the HTL in fabricating the inverted PVSCs. The work function of Nb2CTx HTL was modulated by oxygen plasma treatment through increasing the –O terminated functional groups on the Nb2CTx surface. Under this circumstance, the work function of Nb2CTx HTL was increased due to the enhanced surface dipoles, and the electrons transfer from Nb2C to the –O terminated functional groups. Furthermore, an upward band-bending occurs at the perovskite/HTL interface, which is beneficial to increase the hole transfer efficiency and reduce charge recombination. As a result, the inverted PVSCs with oxygen plasma-treated Nb2CTx HTL achieve the highest power conversion efficiency (PCE) of 20.74% and good stability. Also, the flexible and large area (0.99 cm2) PVSCs achieve the highest PCE of 17.26% and 17.94% by utilizing oxygen plasma-treated Nb2CTx as the HTL. Therefore, this work demonstrates that the Nb2CTx MXene has great potential application in the photovoltaic field, especially in flexible devices.
Active bath-induced localization and collapse of passive semiflexible polymers
Authors: Mousavi S. Mahdiyeh , Gompper Gerhard , Winkler Roland G.
Published: July 2021

The conformational and dynamical properties of a passive polymer embedded in a bath of active Brownian particles (ABPs) are studied by Langevin dynamics simulations. Various activities and ABP concentrations below and above the critical values for motility-induced phase separation (MIPS) are considered. In a homogeneous ABP fluid, the embedded polymer swells with increasing bath activity, with stronger swelling for larger densities. The polymer dynamics is enhanced, with the diffusion coefficient increasing by a power-law with increasing activity, where the exponent depends on the ABP concentration. For ABP concentrations in the MIPS regime, we observe a localization of the polymer in the low-density ABP phase associated with polymer collapse for moderate activities and a reswelling for high activities accompanied by a preferred localization in the high-density ABP phase. Localization and reswelling are independent of the polymer stiffness, with stiff polymers behaving similarly to flexible polymers. The polymer collapse is associated with a slowdown of its dynamics and a significantly smaller center-of-mass diffusion coefficient. In general, the polymer dynamics can only partially be described by an effective (bath) temperature. Moreover, the properties of a polymer embedded in a homogeneous active bath deviate quantitatively from those of a polymer composed of active monomers, i.e., linear chains of ABPs; however, such a polymer exhibits qualitatively similar activity-dependent features.
The magnitude of germinal center reactions is restricted by a fixed number of preexisting niches
Authors: Avancena Patricia , Song Tengfei , Yao Yonghong , Fehlner-Peach Hannah , Diamond Betty , Gu Hua , Rajewsky Klaus , Zou Yong-Rui
Published: July 2021

Significance

The germinal center (GC) reaction generates high-affinity antibody–producing plasma cells and memory B cells that are pivotal for immune responses against pathogens and effective vaccination. However, it remains a challenging task to enhance GC reactions because increased antigen doses or repeated immunization, which should activate more B and T cells for GC formation, do not significantly augment antibody affinity. Here, we show that predetermined GC niches set the ceiling of GC numbers and thus limit GC responses. Clearance of the GC niche occupied by preexisting GC B cells may be a strategy to improve vaccine effectiveness or restore repressed antibody responses in autoimmune patients.
An otopetrin family proton channel promotes cellular acid efflux critical for biomineralization in a marine calcifier
Authors: Chang William W. , Matt Ann-Sophie , Schewe Marcus , Musinszki Marianne , Grüssel Sandra , Brandenburg Jonas , Garfield David , Bleich Markus , Baukrowitz Thomas , Hu Marian Y.
Published: July 2021

Significance

Otopetrins comprise a family of proton channels that are required for the development of calcified structures including otoliths and statoconia in vertebrates. To date, it remains unknown how otopetrins contribute to the calcification process. Using the sea urchin larva, we could demonstrate that the otopetrin ortholog
otop2l
encodes a proton channel that is essential for the formation of the CaCO
3
skeleton.
otop2l
is exclusively expressed by the calcifying primary mesenchyme cells, where it promotes the exit of protons liberated by the mineralization process. Given the deep phylogenetic origin of otopetrins in animals, our work identified a key mechanism in the mineralization process with relevance for many calcifying species and their responses to changes in environmental pH.
Mechanotaxis directs
Pseudomonas aeruginosa
twitching motility
Authors: Kühn Marco J. , Talà Lorenzo , Inclan Yuki F. , Patino Ramiro , Pierrat Xavier , Vos Iscia , Al-Mayyah Zainebe , Macmillan Henriette , Negrete Jose , Engel Joanne N. , Persat Alexandre
Published: July 2021

Significance

Single cells across kingdoms of life explore, prey, escape, or congregate using surface-specific motility. Motile eukaryotic cells use chemotaxis to direct migration on surfaces. However, how bacteria control surface motility remains underexplored.
Pseudomonas aeruginosa
twitches on surfaces by successive extension and retraction of extracellular filaments called type IV pili. Here, we show that
P. aeruginosa
directs twitching by sensing mechanical input generated by type IV pili. The Chp sensory system performs spatially resolved mechanosensing by harnessing two response regulators with antagonistic functions. Our results demonstrate that sensory systems, whose input often remains elusive, can sense mechanical signals to actively steer motility. Furthermore, Chp establishes a signaling principle shared with higher-order organisms, identifying a conserved strategy to transduce spatially resolved signals.
Characterization of DNA–protein complexes by nanoparticle tracking analysis and their association with systemic lupus erythematosus
Authors: Juul-Madsen Kristian , Troldborg Anne , Wittenborn Thomas R. , Axelsen Mads G. , Zhao Huaying , Klausen Lasse H. , Luecke Stefanie , Paludan Søren R. , Stengaard-Pedersen Kristian , Dong Mingdong , Møller Holger J. , Thiel Steffen , Jensen Henrik , Schuck Peter , Sutherland Duncan S. , Degn Søren E. , Vorup-Jensen Thomas
Published: July 2021

Significance

Progress in understanding and treating inflammatory diseases relies on accurate characterization of the molecular pathology. From application of nanoparticle tracking analysis, we expose a fundamental insight in oligomeric protein structure as polyvalent stimulants of autoreactive B cells. Quantification of hydrodynamic radii implicates these large proteins as part of vascular damage, which is an important source of morbidity and death in consequence of autoimmunity. Dysregulated alterations in protein concentration have been often sought as an explanation for diseases. Our work highlights now protein size as a key parameter in the inflammatory response both in and outside lymphoid organs. In this way, our findings may have wide implications for understanding disease associations based on polymerization and hydrodynamic radius changes of biological macromolecules.
Recopilación del léxico disponible dialectal en Andalucía sobre alimentos desde el análisis sociolingüístico de la
muestra sevillana
Authors: Trigo Ibáñez Ester , Clotilde Santos Díaz Inmaculada , Romero Oliva Manuel Francisco
Published: July 2021

El análisis de las voces dialectales de una comunidad hablante es trascendental en múltiples disciplinas: la
dialectología, la etnografía, la sociología y la enseñanza de idiomas, entre otras. Los objetivos de esta investigación son, por
un lado, analizar el léxico dialectal consignado en el léxico disponible de Sevilla y, por otro, recopilar los dialectalismos del
centro de interés “Alimentos y bebidas” presentes en los diccionarios de disponibilidad léxica de las ocho provincias andaluzas.
Para la recogida de datos y la selección de la muestra se han seguido las directrices del Proyecto Panhispánico de Disponibilidad
Léxica. Los resultados estadísticos muestran que las variables socioculturales (sexo, tipo de centro educativo, población y nivel
sociocultural) no influyen significativamente en el léxico dialectal de sus hablantes. En cuanto a Andalucía, se han registrado 95
vocablos que han sido aportados en una sola provincia y 34 que aparecen en dos o más provincias. El repertorio léxico obtenido
supone una valiosa fuente de información para la selección del vocabulario en la enseñanza de español y para realizar futuras
comparaciones diatópicas y diacrónicas tanto en España como en otros países de habla hispana.
El complemento directo y de régimen en español y sus equivalencias en croata
Authors: Mikelenić Bojana , Oliver Antoni
Published: July 2021

El presente estudio se basa en la teoría sobre la relación del complemento directo (CD) y de régimen (CR) en
español –la posibilidad de su coocurrencia en el mismo predicado (Alarcos, 1966; Bosque, 1983; Rojo, 1983) y los predicados en
los que estos dos complementos pueden alternar– para analizar las diferencias en la traducción de estos verbos y sus argumentos al
croata. Mediante búsquedas en un corpus paralelo español-croata y la herramienta ReSiPC (Regular Expression Search in
Parallel Corpora): (Antoni Oliver y Bojana Mikelenić, 2020) desarrollados ambos para esta investigación, se muestran ejemplos de diferentes soluciones al
traducir dichas estructuras –verbos diferentes, el mismo verbo con el régimen diferente, cambio del verbo dependiendo del
significado del complemento–, al igual que ciertos paralelismos entre los esquemas de los dos idiomas. Con esta aproximación se
pretende contribuir en el desarrollo de la metodología y herramientas que facilitarán otros trabajos de esta índole, subrayando
también su valor descriptivo, dado el escaso número de trabajos que comparan estos dos idiomas.
Influencia de la lengua materna y del conocimiento de lenguas
extranjeras en el léxico disponible en ELE
Authors: Hidalgo Gallardo Matías
Published: July 2021

Son numerosas las voces que abogan por la inclusión de la lengua
materna en la enseñanza de lenguas extranjeras en pos de un aprendizaje más
positivo, lo que demuestra la incidencia de esta en la competencia lingüística
de los discentes, y más concretamente en la competencia léxica. También son
numerosos quienes defienden las bondades del multilingüismo en este contexto
educativo. Es, por tanto, evidente el interés que estos dos factores despiertan
en el campo de la investigación y de la didáctica de idiomas. En este sentido,
en el presente trabajo se pretende analizar qué influencia ejercen la lengua
materna (chino mandarín y chino cantonés) –y, en consecuencia, el bilingüismo en
ambas lenguas– y el conocimiento de varias lenguas extranjeras (computadas según
el número) en la competencia léxica en ELE de informantes sinohablantes, más
concretamente en su léxico disponible en español. A través de una serie de
análisis estadísticos comprobamos que la lengua materna no ejerce un impacto
significativo desde una perspectiva cuantitativa, mientras que la competencia
multilingüe sí se revela algo más influyente, aunque solo en las fases iniciales
del proceso de aprendizaje.
Entre la oración y el discurso
Authors: Matute Cristina
Published: July 2021

Este trabajo investiga la adquisición de las funciones adversativa y concesiva del adverbio todavía por parte de
aprendices de español no nativos. Los métodos de enseñanza por lo general solamente presentan su valor como adverbio aspectual, lo
cual permite explorar en qué medida estos aprendices son capaces de desarrollar sin enseñanza explícita funciones más complejas
así como su configuración en la sintaxis discursiva. Dado que los valores adversativo y concesivo únicamente se registran en la
interlengua de aprendices de lenguas maternas en las que existe un elemento equivalente, el estudio especifica las equivalencias
en los niveles léxico, sintáctico y discursivo que parecen subyacer a la transferencia de la L1 a la L2, y concluye que el proceso
se beneficiaría de la enseñanza para llegar a un uso nativo.
Functional immune cell–astrocyte interactions
Authors: Sanmarco Liliana M. , Polonio Carolina M. , Wheeler Michael A. , Quintana Francisco J.
Published: July 2021

Astrocytes are abundant glial cells in the central nervous system (CNS) that control multiple aspects of health and disease. Through their interactions with components of the blood–brain barrier (BBB), astrocytes not only regulate BBB function, they also sense molecules produced by peripheral immune cells, including cytokines. Here, we review the interactions between immune cells and astrocytes and their roles in health and neurological diseases, with a special focus on multiple sclerosis (MS). We highlight known pathways that participate in astrocyte crosstalk with microglia, NK cells, T cells, and other cell types; their contribution to the pathogenesis of neurological diseases; and their potential value as therapeutic targets.
Microglia in Alzheimer's disease at single-cell level. Are there common patterns in humans and mice?
Authors: Chen Yun , Colonna Marco
Published: July 2021

Alzheimer’s disease (AD) is characterized by extracellular aggregates of amyloid β peptides, intraneuronal tau aggregates, and neuronal death. This pathology triggers activation of microglia. Because variants of genes expressed in microglia correlate with AD risk, microglial response to pathology plausibly impacts disease course. In mouse AD models, single-cell RNA sequencing (scRNA-seq) analyses delineated this response as progressive conversion of homeostatic microglia into disease-associated microglia (DAM); additional reactive microglial populations have been reported in other models of neurodegeneration and neuroinflammation. We review all of these microglial signatures, highlighting four fundamental patterns: DAM, IFN–microglia, MHC-II microglia, and proliferating microglia. We propose that all reported microglia populations are either just one or a combination, depending on the clustering strategy applied and the disease model. We further review single-nucleus RNA sequencing (snRNA-seq) data from human AD specimens and discuss reasons for parallels and discrepancies between human and mouse transcriptional profiles. Finally, we outline future directions for delineating the microglial impact in AD pathogenesis.
Single cell analysis of M. tuberculosis phenotype and macrophage lineages in the infected lung
Authors: Pisu Davide , Huang Lu , Narang Vipin , Theriault Monique , Lê-Bury Gabrielle , Lee Bernett , Lakudzala Agnes E. , Mzinza David T. , Mhango David V. , Mitini-Nkhoma Steven C. , Jambo Kondwani C. , Singhal Amit , Mwandumba Henry C. , Russell David G.
Published: July 2021

In this study, we detail a novel approach that combines bacterial fitness fluorescent reporter strains with scRNA-seq to simultaneously acquire the host transcriptome, surface marker expression, and bacterial phenotype for each infected cell. This approach facilitates the dissection of the functional heterogeneity of M. tuberculosis–infected alveolar (AMs) and interstitial macrophages (IMs) in vivo. We identify clusters of pro-inflammatory AMs associated with stressed bacteria, in addition to three different populations of IMs with heterogeneous bacterial phenotypes. Finally, we show that the main macrophage populations in the lung are epigenetically constrained in their response to infection, while inter-species comparison reveals that most AMs subsets are conserved between mice and humans. This conceptual approach is readily transferable to other infectious disease agents with the potential for an increased understanding of the roles that different host cell populations play during the course of an infection.
Thermodynamic anomalies in silicon and the relationship to the phase diagram
Authors: Fijan Domagoj , Wilson Mark
Published: July 2021

The evolution of thermodynamic anomalies are investigated in the pressure–temperature (pT) plane for silicon using the well-established Stillinger–Weber potential. Anomalies are observed in the density, compressibility and heat capacity. The relationships between them and with the liquid stability limit are investigated and related to the known thermodynamic constraints. The investigations are extended into the deeply supercooled regime using replica exchange techniques. Thermodynamic arguments are presented to justify the extension to low temperature, although a region of phase space is found to remain inaccessible due to unsuppressible crystallisation. The locus corresponding to the temperature of minimum compressibility is shown to display a characteristic ‘S’-shape in the pT projection which appears correlated with the underlying crystalline phase diagram. The progression of the anomalies is compared to the known underlying phase diagrams for both the crystal/liquid and amorphous/liquid states. The locations of the anomalies are also compared to those obtained from previous simulation work and (limited) experimental observations.
Validation of proton dose calculation on scatter corrected 4D cone beam computed tomography using a porcine lung phantom
Authors: Schmitz Henning , Rabe Moritz , Janssens Guillaume , Bondesson David , Rit Simon , Parodi Katia , Belka Claus , Dinkel Julien , Kurz Christopher , Kamp Florian , Landry Guillaume
Published: July 2021

Proton therapy treatment for lungs remains challenging as images enabling the detection of inter- and intra-fractional motion, which could be used for proton dose adaptation, are not readily available. 4D computed tomography (4DCT) provides high image quality but is rarely available in-room, while in-room 4D cone beam computed tomography (4DCBCT) suffers from image quality limitations stemming mostly from scatter detection. This study investigated the feasibility of using virtual 4D computed tomography (4DvCT) as a prior for a phase-per-phase scatter correction algorithm yielding a 4D scatter corrected cone beam computed tomography image (4DCBCTcor), which can be used for proton dose calculation. 4DCT and 4DCBCT scans of a porcine lung phantom, which generated reproducible ventilation, were acquired with matching breathing patterns. Diffeomorphic Morphons, a deformable image registration algorithm, was used to register the mid-position 4DCT to the mid-position 4DCBCT and yield a 4DvCT. The 4DCBCT was reconstructed using motion-aware reconstruction based on spatial and temporal regularization (MA-ROOSTER). Successively for each phase, digitally reconstructed radiographs of the 4DvCT, simulated without scatter, were exploited to correct scatter in the corresponding CBCT projections. The 4DCBCTcor was then reconstructed with MA-ROOSTER using the corrected CBCT projections and the same settings and deformation vector fields as those already used for reconstructing the 4DCBCT. The 4DCBCTcor and the 4DvCT were evaluated phase-by-phase, performing proton dose calculations and comparison to those of a ground truth 4DCT by means of dose-volume-histograms (DVH) and gamma pass-rates (PR). For accumulated doses, DVH parameters deviated by at most 1.7% in the 4DvCT and 2.0% in the 4DCBCTcor case. The gamma PR for a (2%, 2 mm) criterion with 10% threshold were at least 93.2% (4DvCT) and 94.2% (4DCBCTcor), respectively. The 4DCBCTcor technique enabled accurate proton dose calculation, which indicates the potential for applicability to clinical 4DCBCT scans.
Corrigendum: Lightning network: a second path towards centralisation of the bitcoin economy (2020 New J. Phys.
22 083022)
Authors: Lin Jian-Hong , Primicerio Kevin , Squartini Tiziano , Decker Christian , Tessone Claudio J
Published: July 2021

The bitcoin lightning network (BLN), a so-called ‘second layer’ payment protocol, was launched in 2018 to scale up the number of transactions between bitcoin owners. In this paper, we analyse the structure of the BLN over a period of 18 months, ranging from 12th January 2018 to 17th July 2019, at the end of which the network has reached 8.216 users, 122.517 active channels and 2.732,5 transacted bitcoins. Here, we consider three representations of the BLN: the daily snapshot one, the weekly snapshot one and the daily-block snapshot one. By studying the topological properties of the binary and weighted versions of the three representations above, we find that the total volume of transacted bitcoins approximately grows as the square of the network size; however, despite the huge activity characterising the BLN, the bitcoins distribution is very unequal: the average Gini coefficient of the node strengths (computed across the entire history of the Bitcoin Lightning Network) is, in fact, ≃0.88 causing the 10% (50%) of the nodes to hold the 80% (99%) of the bitcoins at stake in the BLN (on average, across the entire period). This concentration brings up the question of which minimalist network model allows us to explain the network topological structure. Like for other economic systems, we hypothesise that local properties of nodes, like the degree, ultimately determine part of its characteristics. Therefore, we have tested the goodness of the undirected binary configuration model (UBCM) in reproducing the structural features of the BLN: the UBCM recovers the disassortative and the hierarchical character of the BLN but underestimates the centrality of nodes; this suggests that the BLN is becoming an increasingly centralised network, more and more compatible with a core-periphery structure. Further inspection of the resilience of the BLN shows that removing hubs leads to the collapse of the network into many components, an evidence suggesting that this network may be a target for the so-called split attacks.
Landau damping of electrons with bouncing motion in a radio-frequency plasma*
Authors: Tao Jun , Xiang Nong , Hu Yemin , Huang Yueheng
Published: July 2021

One-dimensional particle simulations have been conducted to study the interaction between a radio-frequency electrostatic wave and electrons with bouncing motion. It is shown that bounce resonance heating can occur at the first few harmonics of the bounce frequency (nω
b,n = 1,2,3,…). In the parameter regimes in which bounce resonance overlaps with Landau resonance, the higher harmonic bounce resonance may accelerate electrons at the velocity much lower than the wave phase velocity to Landau resonance region, enhancing Landau damping of the wave. Meanwhile, Landau resonance can increase the number of electrons in the lower harmonic bounce resonance region. Thus electrons can be efficiently heated. The result might be applicable for collisionless electron heating in low-temperature plasma discharges.
Improved thermal property of strained InGaAlAs/AlGaAs quantum wells for 808-nm vertical cavity surface emitting lasers
Authors: Zhao Zhuang-Zhuang , Xun Meng , Pan Guan-Zhong , Sun Yun , Zhou Jing-Tao , Wu De-Xin
Published: July 2021

The 808-nm vertical cavity surface emitting laser (VCSEL) with strained In0.13Ga0.75Al0.12As/Al0.3Ga0.7As quantum wells is designed and fabricated. Compared with the VCSELs with Al0.05Ga0.95As/Al0.3Ga0.7As quantum wells, the VCSEL with strained In0.13Ga0.75Al0.12As/Al0.3Ga0.7As quantum wells is demonstrated to possess higher power conversion efficiency (PCE) and better temperature stability. The maximum PCE of 43.8% for 10-μm VCSEL is achieved at an ambient temperature of 30 °C. The size-dependent thermal characteristics are also analyzed by characterizing the spectral power and output power. It demonstrates that small oxide-aperture VCSELs are advantageous for temperature-stable performance.
Explosive synchronization in a mobile network in the presence of a positive feedback mechanism
Authors: Qian Dong-Jie
Published: July 2021

Synchronization is a process that describes the coherent dynamics of a large ensemble of interacting units. The study of explosive synchronization transition attracts considerable attention. Here, I report the explosive transition within the framework of a mobile network, while each oscillator is controlled by global-order parameters of the system. Using numerical simulation, I find that the explosive synchronization (ES) transition behavior can be controlled by simply adjusting the fraction of controlled oscillators. The influences of some parameters on explosive synchronization are studied. Moreover, due to the presence of the positive feedback mechanism, I prevent the occurrence of the synchronization of continuousphase transition and make phase transition of the system a first-order phase transition accompanied by a hysteresis loop.
Suppressed light-induced phase transition of CsPbBr2I: Strategies, progress and applications in the photovoltaic field
Authors: Zhang Hushan , Jin Zhiwen
Published: July 2021

The rapid rise in the power conversion efficiency (PCE) of CsPbBr2I-based perovskite solar cells (PSCs), from 4.7% in 2016 to 11.08% in 2020, render it a promising material for use in photovoltaic devices. However, the phase stability and current hysteresis caused by photo-induced phase segregation in CsPbBr2I represent major obstacles to further improvements in the PCE for such devices. In this review, we describe the basic structure and optical properties of CsPbBr2I, and systematically elaborate on the mechanism of the phase transition. We then discuss the strategies in progress to suppress phase transition in CsPbBr2I, and their potential application in the photovoltaic field. Finally, challenges and application prospects for CsPbBr2I PSCs are summarized in the final section of this article.
Efficient MAPbI3 solar cells made via drop-coating at room temperature
Authors: Zhang Lixiu , Zuo Chuantian , Ding Liming
Published: July 2021

Here we demonstrate a room-temperature drop-coating method for MAPbI3 films. By using low-boiling-point solvent, high-quality MAPbI3 films were made by simply casting a drop of solution onto the substrate at room temperature. This approach took advantage of the synergistic effect of good wettability and volatility of the solvent, enabling high nuclei density and compact film at room temperature. The crystal growth in different solvents was in-situ observed by using optical microscope, which helped us to understand the mechanism for the formation of different film morphology. Perovskite solar cells gave a PCE of 18.21%.
A 15 Gbps-NRZ, 30 Gbps-PAM4, 120 mA laser diode driver implemented in 0.15-µm GaAs E-mode pHEMT technology
Authors: Wahba Ahmed , Cheng Lin , Lin Fujiang
Published: July 2021

This paper presents the design and testing of a 15 Gbps non-return-to-zero (NRZ), 30 Gbps 4-level pulse amplitude modulation (PAM4) configurable laser diode driver (LDD) implemented in 0.15-µm GaAs E-mode pHEMT technology. The driver bandwidth is enhanced by utilizing cross-coupled neutralization capacitors across the output stage. The output transmission-line back-termination, which absorbs signal reflections from the imperfectly matched load, is performed passively with on-chip 50-Ω resistors. The proposed 30 Gbps PAM4 LDD is implemented by combining two 15 Gbps-NRZ LDDs, as the high and low amplification paths, to generate PAM4 output current signal with levels of 0, 40, 80, and 120 mA when driving 25-Ω lasers. The high and low amplification paths can be used separately or simultaneously as a 15 Gbps-NRZ LDD. The measurement results show clear output eye diagrams at speeds of up to 15 and 30 Gbps for the NRZ and PAM4 drivers, respectively. At a maximum output current of 120 mA, the driver consumes 1.228 W from a single supply voltage of –5.2 V. The proposed driver shows a high current driving capability with a better output power to power dissipation ratio, which makes it suitable for driving high current distributed feedback (DFB) lasers. The chip occupies a total area of 0.7 × 1.3 mm2.
Structural and electrical characterization of Cu2ZnSnS4 ingot material grown by melting method
Authors: Kerour S. , Bouloufa A. , Lasladj M. , Djessas K. , Medjnoun K.
Published: July 2021

In this work, a Cu2ZnSnS4 (CZTS) ingot is grown via a melting method, then cooled; the resulting molten stoichiometric mixture is sealed off in a quartz ampoule under vacuum. The CZTS powder chemical composition analyses are determined using energy dispersive spectroscopy, and revealing the slightly Cu-rich and Zn-poor character of the ingot. Powder X-ray diffraction analysis reveals a crystalline structure with a kesterite phase formation, and a preferred orientation of (112) plane. The lattice constants of the a- and c- axes, calculated based on the XRD analyses, are a = 5.40 Å and c = 10.84 Å. Based on Hall measurements at room temperature, we find that the crystal exhibits p-type conductivity, with a high concentration of 1018 cm–3, a resistivity of 1.7 Ω cm, and a mobility of 10.69 cm2V–1s–1. Activation energies are estimated based on an Arrhenius plot of conductivity versus 1/T, for a temperature range of 80–350 K, measuring 35 and 160 meV in low- and high-temperature regimes, respectively, which is attributed to complex defects (2CuZn+SnZn) and antisite defects (CuZn), respectively. The observed scattering mechanisms are attributed to ionized impurities and acoustic phonons at low and high temperatures, respectively. The extracted band-gap is 1.37 eV.
Fiber coupled high count-rate single-photon generated from InAs quantum dots
Authors: Chen Yao , Li Shulun , Shang Xiangjun , Su Xiangbin , Hao Huiming , Shen Jiaxin , Zhang Yu , Ni Haiqiao , Ding Ying , Niu Zhichuan
Published: July 2021

In this work, we achieve high count-rate single-photon output in single-mode (SM) optical fiber. Epitaxial and dilute InAs/GaAs quantum dots (QDs) are embedded in a GaAs/AlGaAs distributed Bragg reflector (DBR) with a micro-pillar cavity, so as to improve their light emission extraction in the vertical direction, thereby enhancing the optical SM fiber’s collection capability (numerical aperture: 0.13). By tuning the temperature precisely to make the quantum dot exciton emission resonant to the micro-pillar cavity mode (Q ~ 1800), we achieve a fiber-output single-photon count rate as high as 4.73 × 106 counts per second, with the second-order auto-correlation g
2(0) remaining at 0.08.
Fabrication, characterization, numerical simulation and compact modeling of P3HT based organic thin film transistors
Authors: Dadhich Shubham , Dwivedi A. D. D. , Singh Arun Kumar
Published: July 2021

This paper presents the fabrication, characterization and numerical simulation of poly-3-hexylthiophene (P3HT)-based bottom-gate bottom-contact (BGBC) organic thin film transistors (OTFTs). The simulation is based on a drift diffusion charge transport model and density of defect states (DOS) for the traps in the band gap of the P3HT based channel. It combines two mobility models, a hopping mobility model and the Poole–Frenkel mobility model. It also describes the defect density of states (DOS) for both tail and deep states. The model takes into account all the operating regions of the OTFT and includes sub-threshold and above threshold characteristics of OTFTs. The model has been verified by comparing the numerically simulated results with the experimental results. This model is also used to simulate different structure in four configurations of OTFT e.g. bottom-gate bottom-contact (BGBC), bottom-gate top-contact (BGTC), top-gate bottom-contact (TGBC) and top-gate top-contact (TGTC) configurations of the OTFTs. We also present the compact modeling and model parameter extraction of the P3HT-based OTFTs. The extracted compact model has been further applied in a p-channel OTFT-based inverter and three stage ring oscillator circuit simulation.
Design of unmanned plant monitoring system based on cloud platform
Authors: Tao Li , Wen Sha
Published: July 2021

Aiming at the phenomenon that people are keen to cultivate green plants in life, but because of busy work and business trips. They forget to water in time and cause plants to die due to lack of water. Based on this, this paper proposes a plant unmanned monitoring system design based on cloud platform. Using STM32 as the main control chip and ESP8266 wireless module as the communication module. Using the Internet of Things cloud service technology to send the data collected in the smart home to the cloud combine various sensors and hardware circuit design to realize remote control of the intelligent watering system. The tested system has stable operation, low design cost, easy expansion of functions, strong real-time effect, high precision and broad application prospects. The system debug results show that the design can meet the unmanned online real-time monitoring of plants and it is suitable for home use.
Checking the X.509 Certificate Linter Zlint Based on Request for Comments 5280
Authors: Ren Pinghong , Chen Chu , Yang Donggang
Published: July 2021

The X.509 certificate linter Zlint is helpful to trace changes that a certificate conforms to and violates rules in a process of certificate mutation. Therefore, the correctness of Zlint is very important. We put forward an approach for checking Zlint based on RFC 5280. First, rules adopted by Zlint are extracted from Zlint and checked against rules specified in RFC 5280 to reveal discrepancies. Second, certificates violating intersected rules are generated and employed to test the program of Zlint to find out whether Zlint outputs correct analytical results. Third, rules in RFC 5280 but not in Zlint are analyzed to find out latent missing functions of Zlint. We have implemented our approach and conducted comprehensive experiments. Experimental results show that some rules adopted by Zlint are informal, some analytical results produced by Zlint are not correct, and Zlint misses some functions related to the rules of RFC 5280.
Direct current distribution network protection scheme based on inductive current limiting
Authors: Lv Jiale , Liu Jianwen , Wu Zaijun , Cao Xiaoyong , Yang Jinggang
Published: July 2021

Converter blocking in the case of pole-to-pole short circuit of the direct current (DC) distribution network can cause large-scale power outage and slow system recovery. Given this issue, a scheme of short circuit protection between poles of the DC distribution network based on the cooperation of fault current limiting module and DC circuit breaker is proposed in this paper. According to the inductive current limiting topology, the transient characteristics of the bridge arm current and the fault current on the DC side of the converter are analyzed, and the theoretical calculation method and selection principle of the current limiting inductor parameters are given. The proposed protection scheme can realize the fault ride-through of the converter during the pole-to-pole short circuit, reduce the scope of power outage and quickly restore the system. The simulation results under the PSCAD/EMTDC environment verify the correctness and feasibility of the protection scheme.
Design and technical verification of a new type of subscriber identity module card for internet of vehicles
Authors: Li Yimeng , Ren Xiaoming , Yue Zuhui , Liu Hui , Ding Lanhai
Published: July 2021

The Internet of Vehicles communication security aims to solve the V2X communication security problems under several scenarios, including direct communication and communication based on cellular network, and provides guaranteed communication security for the achievement of business goals such as vehicle-road information collaboration and road safety. Currently, V2X communication security mostly adopts digital certificate technical proposal based on public key infrastructure and is implemented through the HSM security module. However, this solution requires to preset security data such as digital certificate in the HSM module of the vehicle terminal, which has high demands on the production line of the enterprise, the difficulty is predictable. This paper designs a new type of SIM card for Internet of Vehicles based on high performance chip, which can implement the writing and updating operation of security parameters (certificates, keys, etc.) online, which can reduce the requirements for the transformation of the production line of car companies and at the same time, the security of data management is also improved. The validation result indicates that the new SIM card can realize functions such as login authentication, certificate download, signature verification, etc., and its performance meets the requirements of V2X secure communication.
Shared Parking Behavioral Analysis Based on SEM
Authors: Xue Han , Dongdong Zhang , Di Wang , Chen Li
Published: July 2021

Shared parking has become a widely studied topic among researchers due to a rise in urban expansion. Over the past years, several studies have been conducted to investigate the relationship between the choices of shared parking spaces by urban residents and the different factors influencing these choices. This paper analyzes the different factors that can possibly affect parking choice behavior and builds a structural equation model to determine the most influencing attributes.
Study on stability of portal section of High Slope Tunnel Based on numerical analysis
Authors: Ding Libo , Duan Yuxin , Wei Xiaohang , Wang Fuhua , Song Zhanping
Published: July 2021

Due to the complexity of the portal section of high slope tunnel, unsafe accidents are prone to occur. Because of its convenience and accuracy, numerical simulation method is often used in tunnel stability analysis. In this paper, the excavation process of the slope and tunnel at the entrance of the tunnel is simulated by using the finite element software MIDAS-GTS, taking the No.6 tunnel project of the Kovi-Agvida E60 Highway Line in Georgia as an example. According to the results of numerical calculation, although the excavation volume of the slope is large, the displacement is small and the stability is good; the deformation of the surrounding rock of the tunnel is stable, and the displacement of the supporting structure is small, and the maximum displacement is about 20 mm, which is located at the vault. Therefore, the monitoring work should be done well and the support can be strengthened properly during the construction.