bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of low-coherence high-power laser drivers for inertial confinement fusion
Authors: Gao Yanqi , Cui Yong , Ji Lailin , Rao Daxing , Zhao Xiaohui , Li Fujian , Liu Dong , Feng Wei , Xia Lan , Liu Jiani , Shi Haitao , Du Pengyuan , Liu Jia , Li Xiaoli , Wang Tao , Zhang Tianxiong , Shan Chong , Hua Yilin , Ma Weixin , Sun Xun , Chen Xianfeng , Huang Xiuguang , Zhu Jian , Pei Wenbing , Sui Zhan , Fu Sizu
Published: November 2020

The use of low-coherence light is expected to be one of the effective ways to suppress or even eliminate the laser–plasma instabilities that arise in attempts to achieve inertial confinement fusion. In this paper, a review of low-coherence high-power laser drivers and related key techniques is first presented. Work at typical low-coherence laser facilities, including Gekko XII, PHEBUS, Pharos III, and Kanal-2 is described. The many key techniques that are used in the research and development of low-coherence laser drivers are described and analyzed, including low-coherence source generation, amplification, harmonic conversion, and beam smoothing of low-coherence light. Then, recent progress achieved by our group in research on a broadband low-coherence laser driver is presented. During the development of our low-coherence high-power laser facility, we have proposed and implemented many key techniques for working with low-coherence light, including source generation, efficient amplification and propagation, harmonic conversion, beam smoothing, and precise beam control. Based on a series of technological breakthroughs, a kilojoule low-coherence laser driver named Kunwu with a coherence time of only 300 fs has been built, and the first round of physical experiments has been completed. This high-power laser facility provides not only a demonstration and verification platform for key techniques and system integration of a low-coherence laser driver, but also a new type of experimental platform for research into, for example, high-energy-density physics and, in particular, laser–plasma interactions.
Studies on DC transport and terahertz conductivity of granular molybdenum thin films for microwave radiation detector applications
Authors: Sharma Shilpam , Khandelwal Ashish , Amaladass Edward Prabu , S. Abhirami , SK. Ramjan , J. Jayabalan , Mani Awadhesh , Chattopadhyay M. K.
Published: November 2020

The morphological, transport, and terahertz optical properties of DC magnetron-sputtered granular molybdenum thin films with nano-grains embedded in an amorphous molybdenum/molybdenum oxide matrix have been studied in their normal and superconducting states. The superconducting transition temperatures of these films are much higher than that of bulk molybdenum. The optical properties of these thin films have been studied using terahertz time-domain spectroscopy. Their properties have been compared with those of the existing materials used for the development of radiation detectors. The films' resistivity lies in the >100 μΩ cm range, ideal for making highly sensitive radiation detectors. Hall measurements indicate holes as the dominant carriers with very small mean free path and mobility. In the normal state, the films are disordered bad metals. However, they have a large superfluid density and stiffness in their superconducting state. The properties of the films in the normal and superconducting states are promising for their use in cryogenic radiation detectors for microwave, terahertz, and far-infrared frequency ranges.
Quantifying interactions among car drivers using information theory
Authors: Roy Subhradeep
Published: November 2020

Information-theoretic quantities have found wide applications in understanding interactions in complex systems primarily due to their non-parametric nature and ability to capture non-linear relationships. Increasingly popular among these tools is conditional transfer entropy, also known as causation entropy. In the present work, we leverage this tool to study the interaction among car drivers for the first time. Specifically, we investigate whether a driver responds to its immediate front and its immediate rear car to the same extent and whether we can separately quantify these responses. Using empirical data, we learn about the important features related to human driving behavior. Results demonstrate the evidence that drivers respond to both front and rear cars, and the response to their immediate front car increases in the presence of jammed traffic. Our approach provides a data-driven perspective to study interactions and is expected to aid in analyzing traffic dynamics.
On the role of non-diagonal system–environment interactions in bridge-mediated electron transfer
Authors: Acharyya Nirmalendu , Ovcharenko Roman , Fingerhut Benjamin P.
Published: November 2020

Bridge-mediated electron transfer (ET) between a donor and an acceptor is prototypical for the description of numerous most important ET scenarios. While multi-step ET and the interplay of sequential and direct superexchange transfer pathways in the donor–bridge–acceptor (D–B–A) model are increasingly understood, the influence of off-diagonal system–bath interactions on the transfer dynamics is less explored. Off-diagonal interactions account for the dependence of the ET coupling elements on nuclear coordinates (non-Condon effects) and are typically neglected. Here, we numerically investigate with quasi-adiabatic propagator path integral simulations the impact of off-diagonal system–environment interactions on the transfer dynamics for a wide range of scenarios in the D–B–A model. We demonstrate that off-diagonal system–environment interactions can have profound impact on the bridge-mediated ET dynamics. In the considered scenarios, the dynamics itself does not allow for a rigorous assignment of the underlying transfer mechanism. Furthermore, we demonstrate how off-diagonal system–environment interaction mediates anomalous localization by preventing long-time depopulation of the bridge B and how coherent transfer dynamics between donor D and acceptor A can be facilitated. The arising non-exponential short-time dynamics and coherent oscillations are interpreted within an equivalent Hamiltonian representation of a primary reaction coordinate model that reveals how the complex vibronic interplay of vibrational and electronic degrees of freedom underlying the non-Condon effects can impose donor-to-acceptor coherence transfer on short timescales.
Four-component full configuration interaction quantum Monte Carlo for relativistic correlated electron problems
Authors: Anderson Robert J. , Booth George H.
Published: November 2020

An adaptation of the full configuration interaction quantum Monte Carlo (FCIQMC) method is presented for correlated electron problems containing heavy elements and the presence of significant relativistic effects. The modified algorithm allows for the sampling of the four-component spinors of the Dirac–Coulomb(–Breit) Hamiltonian within the relativistic no-pair approximation. The loss of spin symmetry and the general requirement for complex-valued Hamiltonian matrix elements are the most immediate considerations in expanding the scope of FCIQMC into the relativistic domain, and the alternatives for their efficient implementation are motivated and demonstrated. For the canonical correlated four-component chemical benchmark application of thallium hydride, we show that the necessary modifications do not particularly adversely affect the convergence of the systematic (initiator) error to the exact correlation energy for FCIQMC calculations, which is primarily dictated by the sparsity of the wavefunction, allowing the computational effort to somewhat bypass the formal increases in Hilbert space dimension for these problems. We apply the method to the larger problem of the spectroscopic constants of tin oxide, correlating 28 electrons in 122 Kramers-paired spinors, finding good agreement with experimental and prior theoretical relativistic studies.
Cold atmospheric plasma for SARS-CoV-2 inactivation
Authors: Chen Zhitong , Garcia Gustavo , Arumugaswami Vaithilingaraja , Wirz Richard E.
Published: November 2020

Syndrome coronavirus 2 (SARS-CoV-2) infectious virions are viable on various surfaces (e.g., plastic, metals, and cardboard) for several hours. This presents a transmission cycle for human infection that can be broken by developing new inactivation approaches. We employed an efficient cold atmospheric plasma (CAP) with argon feed gas to inactivate SARS-CoV-2 on various surfaces including plastic, metal, cardboard, basketball composite leather, football leather, and baseball leather. These results demonstrate the great potential of CAP as a safe and effective means to prevent virus transmission and infections for a wide range of surfaces that experience frequent human contact. Since this is the first-ever demonstration of cold plasma inactivation of SARS-CoV-2, it is a significant milestone in the prevention and treatment of coronavirus disease 2019 (COVID-19) and presents a new opportunity for the scientific, engineering, and medical communities.
Experimental investigation of a nonspherical water droplet falling in air
Authors: Agrawal Meenu , Katiyar Rajat Kumar , Karri Badarinath , Sahu Kirti Chandra
Published: November 2020

We experimentally investigate the shape oscillations of an initially nonspherical water droplet falling in air using high-speed imaging. We design a customized experimental setup that allows us to study the freely falling droplets of initially oblate/prolate/tilted configurations. The setup uses a pneumatic piston-cylinder arrangement and a superhydrophobically coated plate to propel a droplet upwards in air whose motion is then recorded using a high-speed camera. Due to the propulsive force imparted to the droplet, it undergoes oblate–prolate oscillations and eventually comes to rest at a maximum height, at which time the droplet has a zero vertical velocity and a nonspherical shape with an inclination to the horizontal. We study the effect of the initial aspect ratio and size of the droplet on its shape oscillations during its downward motion.
Towards a Universal Declaration of the Rights of Wetlands
Authors: Davies G. T. , Finlayson C. M. , Pritchard D. E. , Davidson N. C. , Gardner R. C. , Moomaw W. R. , Okuno E. , Whitacre J. C.
Published: November 2020

The rights of Nature, a concept recognised by several courts, legislatures and international governance institutions, is being promoted by some non-governmental organisations, scientists, attorneys, Indigenous peoples, local communities, and others. In this article we propose a Universal Declaration of the Rights of Wetlands, consistent with the 1982 World Charter for Nature. Recognition of these rights supports the provision of ecosystem services essential to human well-being and to other life on Earth. Further, such rights could reinforce efforts to reduce wetland loss and deterioration, thereby slowing climate destabilisation and biodiversity declines. Because world scientists have warned that biodiversity loss, ecosystem degradation and climate destabilisation, which intensify wetland loss, constitute global emergencies, new approaches are required to ensure that wetlands are protected and their benefits to people sustained. The proposed Universal Declaration of the Rights of Wetlands states that wetlands possess rights to: exist; their ecologically determined location in the landscape; natural, connected and sustainable hydrological regimes; ecologically sustainable climatic conditions; naturally occurring biodiversity; regeneration and restoration; integrity of structure, function and evolutionary processes; fulfil natural ecological roles in the Earth’s processes; and be free from pollution and degradation. Recognition of these rights is seen as an essential step in efforts to stop wetland loss and deterioration.
Wetland ecological character and wise use: towards a new framing
Authors: Kumar Ritesh , McInnes Robert , Finlayson C. Max , Davidson Nick , Rissik David , Paul Swapan , Cui Lijuan , Lei Yinru , Capon Samantha , Fennessy Siobhan
Published: November 2020

Ecological character and wise use are central tenets underpinning the Ramsar Convention’s global wetland ambitions. In this paper, we postulate that, given on-going and progressive degradation and destruction of wetlands, these concepts require reframing. So as to overcome the human–nature dualism, which underpins current wetland conservation, we propose that wetlands need to be placed within a social–ecological framing that can accommodate a plurality of worldviews and value systems. This reframing broadens the definition of wetland ecological character and replaces it with a more inclusive and comprehensive term ‘wetland character’. Wise use, consequently, becomes maintenance of wetland character. Further considerations on maintaining wetland character under this construct are presented.
Exploitative leaders incite intergroup warfare in a social mammal
Authors: Johnstone Rufus A. , Cant Michael A. , Cram Dominic , Thompson Faye J.
Published: November 2020

Significance

A classic explanation for the prevalence of complex warfare in human societies is leadership by exploitative individuals who reap the benefits of conflict while avoiding the costs. Here, we extend the classic hawk−dove model to show that leadership of this kind can also explain the evolution of severe collective violence in certain animal societies. We test our model using long-term data from wild banded mongooses, and show that female leaders incite fights with rival groups to gain genetic benefits, while males bear the costs of fighting. The result is unusually severe levels of intergroup violence. Our findings suggest that the decoupling of leaders from the costs that they incite amplifies the destructive nature of intergroup conflict.
Underpotential lithium plating on graphite anodes caused by temperature heterogeneity
Authors: Wang Hansen , Zhu Yangying , Kim Sang Cheol , Pei Allen , Li Yanbin , Boyle David T. , Wang Hongxia , Zhang Zewen , Ye Yusheng , Huang William , Liu Yayuan , Xu Jinwei , Li Jun , Liu Fang , Cui Yi
Published: November 2020

Significance

Metallic lithium plating on the graphite anode is a predominant cause for capacity decays during the fast charging of lithium-ion batteries. This work studies the lithium-plating phenomenon in a previously neglected thermodynamic perspective, taking into account practical temperature distributions within batteries. We show that elevated temperatures could enhance the equilibrium potential of Li
0
/Li
+
, making local lithium plating more thermodynamically favorable. Furthermore, lithium-plating patterns are correlated with temperature heterogeneities, confirming the preferential lithium plating at high-temperature regions due to both kinetic and thermodynamic origins. These findings provide possible explanations of the heterogeneous lithium-plating morphology, deepen the understandings on the lithium plating phenomenon, and will guide future strategies to realize the extreme fast charging of lithium-ion batteries.
Oncogenic allelic interaction in
Xiphophorus
highlights hybrid incompatibility
Authors: Lu Yuan , Sandoval Angel , Voss Sarah , Lai Zhao , Kneitz Susanne , Boswell Will , Boswell Mikki , Savage Markita , Walter Christi , Warren Wes , Schartl Manfred , Walter Ronald
Published: November 2020

Significance

The Bateson–Dobzhansky–Muller (BDM) model describes negative epistatic interactions that occur between genes with a different evolutionary history to account for hybrid incompatibility and is a central theory explaining genetic mechanisms underlying speciation. Since the early 1900 s when the BDM model was forwarded examples of BDM incompatibility have been described in only a few nonvertebrate cases. This study reports the only vertebrate system, with clearly defined interacting loci, that supports the BDM model. In addition, this study also poses that tumorigenesis serves as a novel mechanism that accounts for postzygotic isolation.
Seasonal and diel patterns of abundance and activity of viruses in the Red Sea
Authors: Hevroni Gur , Flores-Uribe José , Béjà Oded , Philosof Alon
Published: November 2020

Significance

The role of viruses in shaping microbial communities in the marine photic zone has been studied extensively in recent years. However, temporal patterns of abundance and activity of highly abundant viral groups and its relation to host abundance are still mostly unconstrained. By tracking changes in rank abundance patterns, we report evidence for seasonal succession in key viral groups alongside a persistence and low transcriptional activity of a large bank population. In addition, we show that high virion abundance does not necessarily translate to high host infection levels, suggesting the coexistence of a diverse repertoire of diel activity and life history traits, even within viral taxonomic groups. Our results highlight the diversity of viral life strategies in the ocean.
Selection on phenotypic plasticity favors thermal canalization
Authors: Svensson Erik I. , Gomez-Llano Miguel , Waller John T.
Published: November 2020

Significance

Organisms are increasingly challenged by increasing temperatures due to climate change. In insects, body temperatures are strongly affected by ambient temperatures, and insects are therefore expected to suffer increasingly from heat stress, potentially reducing survival and reproductive success leading to elevated extinction risks. We investigated how ambient temperature affected fitness in two insect species in the temperate zone. Male and female survivorship benefitted more from low temperatures than did reproductive success, which increased with higher temperatures, revealing a thermal conflict between fitness components. Male body temperature plasticity reduced survival, and natural and sexual selection operated on such thermal plasticity. Our results reveal the negative consequences of thermal plasticity and show that these insects have limited ability to buffer heat stress.
The origin of secondary microseism Love waves
Authors: Gualtieri Lucia , Bachmann Etienne , Simons Frederik J. , Tromp Jeroen
Published: November 2020

Significance

Secondary microseisms are the strongest background seismic vibrations of the Earth and represent the major part of global seismographic data. Secondary microseisms are generated by wind-driven ocean storms, whose energy couples with the solid Earth at the seafloor. State-of-the-art generation theories are unable to justify the presence of secondary microseism Love waves, horizontally polarized surface waves observed in two-thirds of the seismic data archive since the beginning of the 20th century. Using unprecedented high-frequency numerical simulations of global seismic wave propagation, we shed light on this 100-y-old conundrum by demonstrating that secondary microseism Love waves originate ergodically due to lateral heterogeneities in Earth structure.
Superconductivity, correlated insulators, and Wess–Zumino–Witten terms in twisted bilayer graphene
Authors: Christos Maine , Sachdev Subir , Scheurer Mathias S.
Published: November 2020

Significance

When the twist angle between two layers of graphene is close to

1
.

1

°

, the energy of an electron becomes nearly independent of its momentum, and the dominant Coulomb repulsion between the electrons leads to remarkable effects. Experiments have shown novel superconducting and insulating states. We propose here that these states are linked by a topological quantal phase, which is an analog of the Wess–Zumino–Witten term of high-energy physics. This term links spatiotemporal textures of one order with quanta of another order. We classify such orders in the superconducting and insulating states. Our work can help guide experiments studying twisted graphene on the microscopic scale and lead to a fundamental understanding of its remarkable and complex phase diagram.
Potential for sustainable irrigation expansion in a 3 °C warmer climate
Authors: Rosa Lorenzo , Chiarelli Davide Danilo , Sangiorgio Matteo , Beltran-Peña Areidy Aracely , Rulli Maria Cristina , D’Odorico Paolo , Fung Inez
Published: November 2020

Significance

Climate change is expected to reshape the distribution of irrigated lands. Using climatic projections from three global climate models, we investigate global patterns of irrigation water demand and availability in 1.5 °C and 3 °C warmer climates. We find that in up to 35% of currently rain-fed croplands, irrigation could be expanded as an adaptation strategy to climate change without negative environmental externalities on freshwater resources. Irrigation expansion could reduce vulnerability to water stress and improve crop productivity to feed up to 300 million additional people using small-scale water storage and up to 1.4 billion additional people using large-scale water storage. This work contributes to identifying target regions where investments in sustainable intensification of agriculture through irrigation expansion are needed.
Excess of the NF-ĸB p50 subunit generated by the ubiquitin ligase KPC1 suppresses tumors via PD-L1– and chemokines-mediated mechanisms
Authors: Kravtsova-Ivantsiv Yelena , Goldhirsh Gilad , Ivantsiv Alexandra , Ben Itzhak Ofer , Kwon Yong Tae , Pikarsky Eli , Ciechanover Aaron
Published: November 2020

Significance

Recruitment of the immune system to suppress malignant tumors can involve different mechanisms, including inhibition of suppressive immune checkpoints (the enemy of my enemy is my friend), generation of specific CAR-T cells that recognize tumor cells, and immunization against the patient’s tumor antigens. Here we describe a mechanism, where excess of the p50 subunit of the NF-ĸB transcription factor that when pairs with another subunit—p65—is oncogenic, but when generated in excess over p65 and as a result homodimerizes, it suppresses tumors. It appears to act via several mechanisms: it stimulates expression of other cancer suppressors, it inhibits generation of the immune inhibitor PD-L1 (thus unleashes the immune system), and it initiates secretion of chemokines, which are chemical attractants of immune cells.
Syntactic and morphosyntactic phenomena in Modern Greek dialects: The state of the art
Authors: Ralli Angela
Published: November 2020

In this paper I give an overview of several syntactic and morpho-syntactic phenomena applying to a range of Modern Greek dialects. I present a descriptive account of these phenomena, and refer to some possible theoretical analyses put forward by a number of well-known linguists. In certain cases, I offer evidence for the cross-dialectal occurrence of a phenomenon as a contribution to the establishment of syntactic isoglosses, and report some hints of its diachronic development when the available sources permit.
 My data are drawn not only from written sources, but also from the oral material that has been collected in the last six years from several Greek areas, and stored in the Modern Greek Dialects Laboratory (MGDL) of the University of Patras.
 The paper has the following structure: Section 1 contains some general observations with respect to the study and development of Modern Greek dialects. Dialectal word order is presented next (Section 2), followed by certain observations on the use of complementizers (Section 3), negation (Section 4), and sentential particles (Section 5). The issues of infinitival forms and periphrastic tenses (perfect and future) are examined in Section 6, while elements appearing in wh-questions constitute the topic of Section 7. The case form of the indirect object is tackled next (Section 8), and the paper ends with the well-described topic of verbal clitics, which is presented in Section 9. The paper concludes with remarks stressing the importance of research in the field of Modern Greek dialectology.
Spatio-temporal structure and emission of a large plasmoid in atmosphere
Authors: Friedl R , Fantz U , Pilottek I , Schmid D , Steibel S
Published: November 2020

Atmospheric plasmoids with 20–30 cm diameter are generated via a high-voltage discharge above a water surface. They ascend in the ambient air and exist autonomously for several hundreds of milliseconds. The plasma processes leading to an emission of visible light for more than 350 ms after detachment from the energy supply are still unknown. Visual and spectroscopic high-speed diagnostics with spatial resolution are thus applied. It is shown for the first time that the free-floating body turns to a torus ring to the end of its lifetime, which ascends in air up to more than 1.5 m and radiates longer than 1.5 s in the infrared spectral range, only limited by the structural circumstances in the laboratory. Vortex formation is thus endorsed as being responsible for the structural integrity of the plasma during the autonomous phase. Emission in the optical spectral range (UV-NIR) is limited to the first 500 ms and is governed by radiation from the tap water contents without the influx of ambient air into the plasma. The OH A-X transition is the most intense emission during the entire visible evolution of the plasmoid. Atomic hydrogen emission is observed only during the first 100 ms close to the central electrode (CE) and is highly dynamic, while emission from dissolved salts is detected during the later evolution but is mostly overlaid by a continuum radiation, which is clearly non-thermal. Using the omnipresent OH emission, the optical emission profile of the main plasmoid is shown to be broad in the center and is rotationally symmetric. The radiated energy from the OH radical integrated over the entire plasmoid evolution is less than 100 J, which is about 3% of the total energy dissipated into the plasma. Emission from dissolved sodium is used to track the plasma channel, which connects the main plasmoid to the CE, during its ascension after energy shut-down giving a fourfold ascension velocity compared to the main plasmoid.
Investigation of soft and living matter using a micro-extensional rheometer
Authors: Dubey Sushil , Veer Sukh , Seshagiri Rao R V , Kalelkar Chirag , Pullarkat Pramod A
Published: November 2020

Rheological properties of a material often require to be probed under extensional deformation. Examples include fibrous materials such as spider-silk, high-molecular weight polymer melts, and the contractile response of living cells. Such materials have strong molecular-level anisotropies which are either inherent or are induced by an imposed extension. However, unlike shear rheology, which is well-established, techniques to perform extensional rheology are currently under development and setups are often custom-designed for the problem under study. In this article, we present a versatile device that can be used to conduct extensional deformation studies of samples at microscopic scales with simultaneous imaging. We discuss the operational features of this device and present a number of applications.
Raman spectroscopy and lattice dynamics calculations of tetragonally-structured single crystal zinc phosphide (Zn3P2) nanowires
Authors: Stutz Elias Z , Escobar Steinvall Simon , Litvinchuk Alexander P , Leran Jean-Baptiste , Zamani Mahdi , Paul Rajrupa , Fontcuberta i Morral Anna , Dimitrievska Mirjana
Published: November 2020

Earth-abundant and low-cost semiconductors, such as zinc phosphide (Zn3P2), are promising candidates for the next generation photovoltaic applications. However, synthesis on commercially available substrates, which favors the formation of defects, and controllable doping are challenging drawbacks that restrain device performance. Better assessment of relevant properties such as structure, crystal quality and defects will allow faster advancement of Zn3P2, and in this sense, Raman spectroscopy can play an invaluable role. In order to provide a complete Raman spectrum reference of Zn3P2, this work presents a comprehensive analysis of vibrational properties of tetragonally-structured Zn3P2 (space group P42/nmc) nanowires, from both experimental and theoretical perspectives. Low-temperature, high-resolution Raman polarization measurements have been performed on single-crystalline nanowires. Different polarization configurations have allowed selective enhancement of A1g, B1g and Eg Raman modes, while B2g modes were identified from complementary unpolarized Raman measurements. Simultaneous deconvolution of all Raman spectra with Lorentzian curves has allowed identification of 33 peaks which have been assigned to 34 (8 A1g + 9 B1g + 3 B2g + 14 Eg) out of the 39 theoretically predicted eigenmodes. The experimental results are in good agreement with the vibrational frequencies that have been computed by first-principles calculations based on density functional theory. Three separate regions were observed in the phonon dispersion diagram: (i) low-frequency region (<210 cm−1) which is dominated by Zn-related vibrations, (ii) intermediate region (210–225 cm−1) which represents a true phonon gap with no observed vibrations, and (iii) high-frequency region (>225 cm−1) which is attributed to primarily P-related vibrations. The analysis of vibrational patterns has shown that non-degenerate modes involve mostly atomic motion along the long crystal axis (c-axis), while degenerate modes correspond primarily to in-plane vibrations, perpendicular to the long c-axis. These results provide a detailed reference for identification of the tetragonal Zn3P2 phase and can be used for building Raman based methodologies for effective defect screening of bulk materials and films, which might contain structural inhomogeneities.
Gaussian distribution of inhomogeneous nickel–vanadium Schottky interface on silicon (100)
Authors: Soltani S , Gammon P M , Pérez-Tomas A , Ferhat Hamida A , Terchi Y
Published: November 2020

This study presents the characterization of the nickel–vanadium (NiV) Schottky diode on n-type silicon (Si) in the temperature range 75 K–300 K. The experimental current–voltage (I–V) measurements are first analyzed by using the thermionic emission (TE) theory. For this purpose, the vertical optimization method is used to find the values of the TE parameters, i.e. the values of the ideality factor, barrier height, and series resistance. It is found that these parameters exhibit strong temperature dependence, i.e. an increase of the ideality factor and a decrease of the barrier height

ϕ

B

and the series resistance

R

s

when the temperature decreases, which is due to inhomogeneities at the Schottky interface. Therefore, we employ Werner’s model under the assumption of a Gaussian distribution to analyze the temperature dependence of the TE parameters. The mean and standard deviation of the barrier height are obtained as

ϕ

B

0

=

 

0.68

 eV

and

σ
0

=

 

53.665

, respectively. In addition, we show that the apparent barrier height and apparent ideality factor are in accordance with Werner’s model. Furthermore, we use the modified Richardson plot to find the value of the Richardson constant. The obtained value of the latter is

A
∗

=

 

111.56

 

A cm−2 K−2 and is very close to the theoretical value of 112 A cm−2 K−2 of n-type Si. Finally, we investigate the temperature dependence of the ideality factor and show the validity of the T0-effect for the NiV/Si Schottky diode.
Separating strain sensor based on dual-resonant circular patch antenna with chipless RFID tag
Authors: Wan Guochun , Kang Wenhao , Wang Chao , Li Wenzhao , Li Mengmeng , Xie Liyu , Chen Lan
Published: November 2020

In the field of structural health detection, since the sensor needs to be directly bonded to the measured object, it is difficult to stably transmit the RFID information and realize the passive wireless structure strain detection. To circumvent these difficulties, this paper innovatively proposes a dual-resonant circular microstrip patch antenna (CMPA) sensor with chipless RFID tag. The information of the RFID tag can be changed that allows the sensor to be deployed on a large scale. The separating sensor includes chipless RFID tag layer and dual-resonant CMPA layer, which can simultaneously reflect RFID tag information and strain information.The design of separated layers can minimize the resonant frequency shift of ID tags when stress is implemented on CMPA strain part. Current distribution analysis and equivalent circuit are used to study the strain size and direction. Experiments show that the offset of the resonant frequency of the sensor antenna has linear relationship with the lateral and longitudinal strains. The correlation coefficients are 0.9284 and 0.9235 respectively, and the sensitivity coefficient of the lateral and longitudinal strain is 528 MHz ϵ
−1 and 384 MHz ϵ
−1. At the same time, the readability of the RFID tag information is maintained.
Dynamical phase diagram of ultracold Josephson junctions
Authors: Xhani K , Galantucci L , Barenghi C F , Roati G , Trombettoni A , Proukakis N P
Published: November 2020

We provide a complete study of the phase diagram characterising the distinct dynamical regimes emerging in a three-dimensional Josephson junction in an ultracold quantum gas. Considering trapped ultracold superfluids separated into two reservoirs by a barrier of variable height and width, we analyse the population imbalance dynamics following a variable initial population mismatch. We demonstrate that as the chemical potential difference is increased, the system transitions from Josephson plasma oscillations to either a dissipative (in the limit of low and narrow barriers) or a self-trapped regime (for large and wider barriers), with a crossover between the dissipative and the self-trapping regimes which we explore and characterize for the first time. This work, which extends beyond the validity of the standard two-mode model, connects the role of the barrier width, vortex rings and associated acoustic emission with different regimes of the superfluid dynamics across the junction, establishing a framework for its experimental observation, which is found to be within current experimental reach.
Effective Langevin equations for a polar tracer in an active bath
Authors: Knežević Miloš , Stark Holger
Published: November 2020

We study the motion of a polar tracer, having a concave surface, immersed in a two-dimensional suspension of active particles. Using Brownian dynamics simulations, we measure the distributions and auto-correlation functions of force and torque exerted by active particles on the tracer. The tracer experiences a finite average force along its polar axis, while all the correlation functions show exponential decay in time. Using these insights we construct the full coarse-grained Langevin description for tracer position and orientation, where the active particles are subsumed into an effective self-propulsion force and exponentially correlated noise for both translations and rotations. The ensuing mesoscopic dynamics can be described in terms of five dimensionless parameters. We perform a thorough parameter study of the mean squared displacement, which illustrates how the different parameters influence the tracer dynamics, which crosses over from a ballistic to diffusive motion. We also demonstrate that the distribution of tracer displacements evolves from a non-Gaussian shape at early stages to a Gaussian behavior for sufficiently long times. Finally, for a given set of microscopic parameters, we establish a procedure to estimate the matching parameters of our effective model, and show that the resulting dynamics is in a very good quantitative agreement with the one obtained in Brownian dynamics simulations.
Mean first-passage time to a small absorbing target in an elongated planar domain
Authors: Grebenkov Denis S. , Skvortsov Alexei T.
Published: November 2020

We derive an approximate but fully explicit formula for the mean first-passage time (MFPT) to a small absorbing target of arbitrary shape in a general elongated domain in the plane. Our approximation combines conformal mapping, boundary homogenisation, and Fick–Jacobs equation to express the MFPT in terms of diffusivity and geometric parameters. A systematic comparison with a numerical solution of the original problem validates its accuracy when the starting point is not too close to the target. This is a practical tool for a rapid estimation of the MFPT for various applications in chemical physics and biology.
Thermal transport of bio-convection flow of micropolar nanofluid with motile microorganisms and velocity slip effects
Authors: Alqarni M S , Waqas Hassan , Imran Muhammad , Alghamdi Metib , Muhammad Taseer
Published: November 2020

The motivation of current research is to explore thermo-bioconvection micropolar liquid flow subject to motile microorganisms and nanomaterials. Rheological model characteristics of Maxwell viscoelasticity-based micropolar nanoliquid are considered for analysis. Slip mechanisms and stratification phenomenon are accounted. Heat and concentration diffusions are characterized by exploiting the Cattaneo-Christov fluxes for heat and mass. Aspects of thermophoresis, thermal radiation and Brownian motion are also accounted. The dimensional non-linear boundary value problems are rendered into the dimensionless ODE’s by utilizing admissible transformations and then tackled numerically by utilizing bvp4c technique via computational commercial software MATLAB. Significance of sundry variables against velocity, temperature, concentration of nanoparticles and microorganism’s concentration are described through graphs and numeric data.
Comparison between low optical absorption models for pump-probe transient thermal lens spectroscopy: a theoretical and experimental study
Authors: Isidro-Ojeda M A , Marín E
Published: November 2020

We compare the most widely used low optical absorption models based on the Fresnel diffraction theory for the description of the time-resolved thermal lens signal in a dual-beam pump-probe mode-mismatched configuration. In this work, we will name one of them as the numerical mode-mismatched model. The others are two simplified approximations of it that will be referred to as the analytical mode-mismatched and the reduced mode-mismatched (RMM) model. The limits of application of these approximations are discussed based on computational calculations and experimental measurements performed under conditions that neglect contributions to the thermal lens signal generation of mechanisms different from optical absorption, heat diffusion and the propagation of the excitation and probe laser beams. It is shown that for fractional changes of the probe beam greater than about 15% these approximations must be used carefully, particularly the RMM model.
Deuterium retention in liquid tin exposed to atomic deuterium flux
Authors: Zaplotnik Rok , Nemanič Vincenc , Žumer Marko , Kovač Janez , Mozetič Miran
Published: November 2020

Liquid tin samples at a temperature of 250 °C were exposed to neutral deuterium atoms at a flux of about 1024 m−2 s−1. The source of deuterium (D) atoms was the flowing afterglow of a low-pressure deuterium plasma sustained with a microwave discharge in the surfatron mode. The samples were analyzed by thermal desorption spectroscopy and time of flight secondary-ion mass spectrometry. An immeasurably low concentration of deuterium was detected in the pure tin. However, within the native layer of tin oxide, up to 165 ppm D/Sn was absorbed while the sample was exposed to D atoms. The deuterium concentration in the solid samples peaked at the D fluence of about 5 × 1025 m−2. At the fluence of several 1026 m−2 the concentration dropped below the detection limit, which was about 50 ppb D/Sn. The results were explained by the reduction of the oxide film under exposure to D atoms at large fluences. Thus, the retention of hydrogen isotopes in the liquid tin divertor of a fusion reactor is unlikely since the effect of the plasma makes it possible to reduce the tin oxide layer.
X-point radiation, its control and an ELM suppressed radiating regime at the ASDEX Upgrade tokamak
Authors: Bernert M. , Janky F. , Sieglin B. , Kallenbach A. , Lipschultz B. , Reimold F. , Wischmeier M. , Cavedon M. , David P. , Dunne M.G. , Griener M. , Kudlacek O. , McDermott R.M. , Treutterer W. , Wolfrum E. , Brida D. , Février O. , Henderson S. , Komm M.
Published: November 2020

Future fusion reactors require a safe, steady state divertor operation. The required detached operation is, in tokamaks with metal walls, usually achieved by seeding of impurities, such as nitrogen. With strong seeding levels, the dominant radiation is emitted from a small, poloidally localized volume inside the confined region, in the vicinity of the X-point. The location of the radiating volume is observed to vary relative to the X-point depending on seeding and power levels, i.e. depending on the degree of detachment. At the ASDEX Upgrade tokamak, the position of the radiator relative to the X-point can be controlled in real time by a modulation of the nitrogen puff level. At a certain height of the radiator above the X-point, an ELM-suppressed regime is observed with minimal reduction of confinement. While the control of the X-point radiator already allows operation in full detachment at a dissipated power fraction of around 95 %, which is required for a future reactor and was previously never achieved in a controlled way, such an ELM-suppressed regime additionally eliminates the challenge of the transient, intolerably high heat fluxes by ELMs. Both requirements are met in the presented regime while maintaining a high energy confinement at high density.
Simulation Analysis of Mechanical Performance of the Broadband Coaxial Step Attenuator
Authors: Kong Zhigang , Liu Peng
Published: November 2020

In this paper, the structure and performance of broadband coaxial step attenuator are studied by simulation. Through the finite element static structure simulation, the stress and strain of the internal structure of the step attenuator are analyzed. The contact pressure, contact state and contact stability between the reed and the attenuation unit are analyzed. The theoretical analysis and calculation of the fatigue life with the nominal stress method are carried out. At the same time, the structure of the reed is optimized and improved for better performance. Then the dynamic mechanical properties of the structure are analyzed. The finite element simulation results show that the maximum stress is 395.53MPa. Due to the high stress in the contact area between the reed and the ejector rod, there will be micro cracks at these stress concentration positions under the constant impact of the ejector rod on the reed. The micro cracks gradually grow up and finally form the macro cracks, which lead to the reed fracture.
Research on Lightweight Design of Automobile Collision Safety Structure Based on Multiple Materials
Authors: Wang Tingting , Dong Ruoyan , Zhang Shan , Qin Dongchen
Published: November 2020

With the increase in car ownership and the increasing pressure of energy conservation and emission reduction, the lightweighting of cars has become an important development direction for traditional cars to reduce emissions and increase the endurance of electric vehicles. Aiming at the lightweight design of automobile crash safety structure, this paper proposes a variable section and multiple materials vehicle lightweight design framework based on collision safety. Taking a certain type of racing car frame as the research object, the lightweight design is carried out, and the optimal design scheme of racing car frame with good collision safety performance is obtained. Taking the lightest frame mass as the design goal, the optimal latin square design and response surface model are used to optimize the thickness of each pipe frame, and the lightweight frame optimization scheme based on the improvement of collision safety performance is obtained. Finally, under the premise that the peak acceleration of the cockpit is reduced by 20.02% and the amount of intrusion at the brake pedal is reduced by 25.31%, weight reduction of 14.38% is achieved. Based on the actual engineering situation, this paper constructs a lightweight design framework for automobiles based on collision safety, and provides an efficient optimization process for lightweight design of automobiles.
A Discussion of Mathematical Models Used to Simulate the Vertical Mass Flux Profile of the Mega-Dune
Authors: Shi Huanyu , Dong Zhibao , Xiao Nan , Huang Qinni
Published: November 2020

The research of the sand transport profile is significant for the calculation of sediment transport rates and the improvement of previous models. However, there are few suitable mathematical models to simulate the “stratification pattern” of the vertical mass flux profile in sandy lands. The present study measured the sand flux vertical distribution within 30cm height with 2cm division at the windward slope and the top of the mega dune in the hinterland of Badain Jaran Desert in winter and used the method of function fitting to analyze the flux density profiles above each observation site. The results show that: (1) The sand-drift activity at each site of the mega-dune is in the erosional state. (2) Low temperature and snow cover have little effect on the vertical mass flux profile. (3) The slope is the key factor to affect the vertical mass flux profile. It is significant in the middle and upper-middle of the windward slope, the sediment transport rate decreases exponentially with the increase of the height. At the top of the slope, the sediment transport rate increases at the beginning and then decreases with the increase of the height, which is an Extreme function distribution. The present study use suitable mathematical models to simulate the stratification pattern of the sand transport profile in sandy lands, explains the physical significance of each fitting coefficients in the function, discusses the effect of the slope on the vertical mass flux profile, and provides theoretical support for the practice of sand-control.
Code Conversion Method on Process-in-Memory Platform
Authors: Liu Jinhui , Zhao Chen , Du Fangzhou , Liu Xuwen
Published: November 2020

Process-in-Memory (PIM) has become a favorable solution for data intensive applications with its advantages of placing processing units in or near memory, reducing the movement of data between memory and processing unit. However, most recent PIM platforms have relatively large limitations in terms of computing flexibility and types of computing, and programming is complicated, which cannot provide a unified programming framework. Therefore, it becomes a challenge to deploy the code to the hardware, which severely restricts the application development on the PIM platform. This paper presents a method of code conversion based on the PIM platform, which allows users to develop applications on the PIM platform with the high-level programming language, makes the PIM platform more accessible in the development of data intensive applications.
Research on Supply Chain Collaborative Manufacturing Mode
Authors: Li Mengliang , Yang Hong , Guo Xiong
Published: November 2020

In this paper, through the study of supply chain collaborative manufacturing business process and resource interaction mode, around the core production enterprises, from collaborative planning, collaborative procurement, collaborative production, collaborative logistics and collaborative service five supply chain business links. With the support of supply chain collaborative manufacturing platform, the overall competitiveness of supply chain collaborative manufacturing is improved, and the real-time interaction and information sharing of material flow, information flow and capital flow among suppliers, manufacturers and customers are realized.
Numerical Simulation on Perforation of Conical Nose Rigid Projectile into Thick Aluminum Alloy Target
Authors: Xu Ruihuai
Published: November 2020

In this paper, the penetration and perforation process of the conical nose rigid projectile into thick aluminum alloy target was simulated numerically by using finite element method. The residual velocity was obtained by using numerical simulation. Time history of the projectile velocity is presented. Comparison of the present experimental results with numerical data from MSC.DYTRAN code indicates validity of the proposed simulation. The simulation results indicate that in the same conditions, the simulated residual velocity is in generally good agreement with the existing data. It shows the validity and exactness of the numerical simulation.