bluuebunny/crossref_metadata_2025 huggingface dataset:
Elastic Rayleigh–Taylor and Richtmyer–Meshkov instabilities in spherical geometry
Authors: Sun Y. B. , Zeng R. H. , Tao J. J.
Published: December 2020

An exact theoretical analysis is presented, mainly concerning linearly elastic Rayleigh–Taylor (RT) and Richtmyer–Meshkov (RM) instabilities at spherical interfaces by using the decomposition method. A stability analysis is performed to investigate the growth rates of instability with the degree of spherical harmonics n, dimensionless radius Br, Atwood number At, and elastic ratio T. Generally, spherical RT and RM instabilities resemble their planar counterparts when Br or n is large. However, low mode perturbations behave quite differently from planar ones, which is also observed in experiments in inertial confinement fusion and in theoretical analysis in geophysics. An analytical expression is obtained to study the dependence of the cutoff radius. There exist two kinds of it: a small one at which the most-active mode cannot be activated and a larger one that is similar to the planar one. In addition, the elastic parameter strongly affects the evolution of a mode with a lower number. The method is extended to study the RT instability at the interface between an elastic solid and a viscous fluid, which is relevant to some situations encountered experimentally. Finally, RM instability in elastic solids is also investigated, in particular, with regard to the evolution of RM instability with low-mode asymmetries. This method is able to provide guidelines for further studying spherical RT and RM instabilities in complex situations, including the finite thickness effects, elastoplastic properties, and Bell–Plesset effects.
Activation energies for two steps in the S2 → S3 transition of photosynthetic water oxidation from time-resolved single-frequency infrared spectroscopy
Authors: Mäusle Sarah M. , Abzaliyeva Aiganym , Greife Paul , Simon Philipp S. , Perez Rebeca , Zilliges Yvonne , Dau Holger
Published: December 2020

The mechanism of water oxidation by the Photosystem II (PSII) protein–cofactor complex is of high interest, but specifically, the crucial coupling of protonation dynamics to electron transfer (ET) and dioxygen chemistry remains insufficiently understood. We drove spinach-PSII membranes by nanosecond-laser flashes synchronously through the water-oxidation cycle and traced the PSII processes by time-resolved single-frequency infrared (IR) spectroscopy in the spectral range of symmetric carboxylate vibrations of protein side chains. After the collection of IR-transients from 100 ns to 1 s, we analyzed the proton-removal step in the S2 ⇒ S3 transition, which precedes the ET that oxidizes the Mn4CaOx-cluster. Around 1400 cm−1, pronounced changes in the IR-transients reflect this pre-ET process (∼40 µs at 20 °C) and the ET step (∼300 µs at 20 °C). For transients collected at various temperatures, unconstrained multi-exponential simulations did not provide a coherent set of time constants, but constraining the ET time constants to previously determined values solved the parameter correlation problem and resulted in an exceptionally high activation energy of 540 ± 30 meV for the pre-ET step. We assign the pre-ET step to deprotonation of a group that is re-protonated by accepting a proton from the substrate–water, which binds concurrently with the ET step. The analyzed IR-transients disfavor carboxylic-acid deprotonation in the pre-ET step. Temperature-dependent amplitudes suggest thermal equilibria that determine how strongly the proton-removal step is reflected in the IR-transients. Unexpectedly, the proton-removal step is only weakly reflected in the 1400 cm−1 transients of PSII core complexes of a thermophilic cyanobacterium (T. elongatus).
Erbium energy levels in GaN grown by hydride vapor phase epitaxy
Authors: Yan Y. Q. , Smith T. B. , Li J. , Lin J. Y. , Jiang H. X.
Published: December 2020

Erbium doped GaN (Er:GaN) is a promising candidate as a novel gain medium for solid-state high energy lasers (HELs) due to its superior physical properties over a synthetic garnet such as Nd:YAG. Er:GaN emits in the 1.5 µm region, which is retina-safe and has a high transmission in the air. We report photoluminescence (PL) studies performed on Er:GaN epilayers synthesized by the hydride vapor phase epitaxy (HVPE) technique. The room temperature PL spectra of HVPE grown Er:GaN epilayers resolved as many as 11 and seven emission lines in the 1.5 µm and 1.0 µm wavelength regions, respectively, corresponding to the intra-4f shell transitions between Stark levels from the first (4I13/2) and the second (4I11/2) excited states to the ground state (4I15/2) of Er3+ in GaN. The observed peak positions of these transitions enabled the construction of the detailed energy levels in Er:GaN. The results agree well with those of the calculation based on a crystal field analysis. Precise determination of the detailed energy levels of the Stark levels in the 4I11/2, 4I13/2, and 4I15/5 states is critically important for the realization of HELs based on Er:GaN.
Bootstrap embedding with an unrestricted mean-field bath
Authors: Tran Henry K. , Ye Hong-Zhou , Van Voorhis Troy
Published: December 2020

A suite of quantum embedding methods have recently been developed where the Schmidt decomposition is applied to the full system wavefunction to derive basis states that preserve the entanglement between the fragment and the bath. The quality of these methods can depend heavily on the quality of the initial full system wavefunction. Most of these methods, including bootstrap embedding (BE) [M. Welborn et al; J. Chem. Phys. 145, 074102 (2016)], start from a spin-restricted mean-field wavefunction [call this restricted BE (RBE)]. Given that spin-unrestricted wavefunctions can capture a significant amount of strong correlation at the mean-field level, we suspect that starting from a spin-unrestricted mean-field wavefunction will improve these embedding methods for strongly correlated systems. In this work, BE is generalized to an unrestricted Hartree–Fock bath [call this unrestricted BE (UBE)], and UBE is applied to model hydrogen ring systems. UBE’s improved versatility over RBE is utilized to calculate high spin symmetry states that were previously unattainable with RBE. Ionization potentials, electron affinities, and spin-splittings are computed using UBE with accuracy on par with spin-unrestricted coupled cluster singles and doubles. Even for cases where RBE is viable, UBE converges more reliably. We discuss the limitations or weaknesses of each calculation and how improvements to RBE and density matrix embedding theory these past few years can also improve UBE.
Creation of large temperature anisotropies in a laboratory plasma
Authors: Beatty C. B. , Steinberger T. E. , Aguirre E. M. , Beatty R. A. , Klein K. G. , McLaughlin J. W. , Neal L. , Scime E. E.
Published: December 2020

Ion temperature anisotropy in an expanding magnetized plasma is investigated using laser induced fluorescence. Parallel and perpendicular ion velocity distribution functions (IVDFs) were measured simultaneously with high spatial resolution in the expanding plasma. Large ion temperature anisotropies (T⊥i/T∥i∼10) are observed in a conical region at the periphery of the expanding plasma plume. A simple 2D Boris stepper model that incorporates the measured electric field structure is able to reproduce the gross features of the measured perpendicular IVDFs. A Nyquist stability analysis of the measured IVDFs suggests that multiple instabilities with k⊥ρi∼1 and k||ρi∼0.2 are likely to be excited in these plasmas.
Direct numerical simulation and stability analysis of the transitional boundary layer on a marine propeller blade
Authors: Jing Z. , Ducoin A.
Published: December 2020

It is generally assumed that the cross-flow instability exists on propeller blade boundary layers due to their similarity with the rotating disk flow. However, to the best of our knowledge, there is no experimental or numerical evidence that directly shows the existence of the cross-flow instability on propellers. In this paper, we present a direct numerical simulation of the boundary layer flow around a marine propeller blade. For the investigated case, the cross-flow velocity inside the attached laminar boundary layer is smaller than the rotating disk case, but it is large enough to lead to the cross-flow instability. The wave-numbers and wave-direction of the cross-flow vortices observed agree well with the prediction of linear stability theory. Linearized Navier–Stokes simulations show that the boundary layer is absolutely unstable in the radial direction but convectively unstable in the streamwise direction. A significant flow direction deviation between laminar and turbulent regions is also observed on the blade surface. In the separation bubble, there is an unusually large radial velocity (around 50% of the inviscid streamwise velocity). Both the flow direction deviation and the large radial velocity in the separation bubble can be explained by the relationship between Coriolis forces and circumferential velocities.
A lattice Boltzmann modeling of viscoelastic drops’ deformation and breakup in simple shear flows
Authors: Wang Di , Tan Danielle S. , Khoo Boo Cheong , Ouyang Zhenyu , Phan-Thien Nhan
Published: December 2020

The deformation and breakup of viscoelastic drops in simple shear flows of Newtonian liquids are studied numerically. Our three-dimensional numerical scheme, extended from our previous two-dimensional algorithm, employs a diffusive-interface lattice Boltzmann method together with a lattice advection–diffusion scheme, the former to model the macroscopic hydrodynamic equations for multiphase fluids and the latter to describe the polymer dynamics modeled by the Oldroyd-B constitutive model. A block-structured adaptive mesh refinement technique is implemented to reduce the computational cost. The multiphase model is validated by a simulation of Newtonian drop deformation and breakup under an unconfined steady shear, while the coupled algorithm is validated by simulating viscoelastic drop deformation in the shear flow of a Newtonian matrix. The results agree with the available numerical and experimental results from the literature. We quantify the drop response by changing the polymer relaxation time λ and the concentration of the polymer c. The viscoelasticity in the drop phase suppresses the drop deformation, and the steady-state drop deformation parameter D exhibits a non-monotonic behavior with the increase in Deborah number De (increase in λ) at a fixed capillary number Ca. This is explained by the two distribution modes of the polymeric elastic stresses that depend on the polymer relaxation time. As the concentration of the polymer c increases, the degree of suppression of deformation becomes stronger and the transient result of D displays an overshoot. The critical capillary number for unconfined drop breakup increases due to the inhibitive effects of viscoelasticity. Different distribution modes of elastic stresses are reported for different De.
CL-20/CAB energetic composite microspheres prepared by premix membrane emulsification
Authors: Wang Jiechao , An Chongwei , Ye Baoyun , Xu Ruixuan , Liu Qian , Wang Jingyu , Dong Jun
Published: December 2020

Premix membrane emulsification is a quick and efficient method to prepare emulsion. Pre-emulsion was prepared by dissolving 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) and cellulose acetate butyrate (CAB) in ethyl acetate, and the mixture was added to an aqueous solution containing a surfactant. Then, the droplet uniform emulsion through the transmembrane was formed. The composites with the core–shell structure were obtained after evaporating the solvent. The results displayed that the morphological structure of CL-20 based composite could change from the dumbbell-shaped structure to spherical structure with an increase in the CAB content. Based on the impact sensitivity and thermal properties, the composite enhanced the safety. Meanwhile, a remarkable enhancement in the decomposition peak temperature (Tp0) and the critical temperature of the explosion (Tb) at a relatively low content of CAB (3 wt. %, 5 wt. % and 10 wt. %) was also noted. This approach provides a faster way for the design and preparation of polymer composites.
Polyoxometalates as electron and proton reservoir assist electrochemical CO2 reduction
Authors: Lang Zhongling , Miao Jun , Lan Yangchun , Cheng Jiaji , Xu Xiaoqian , Cheng Chun
Published: December 2020

Limited and non-renewable fossil fuels prompt people to develop CO2 reduction technology. Polyoxometalate (POM)-based electrocatalysts have flourished due to their intriguing molecular structure and unique redox chemistry. In this Research Update, the investigations of POM-based electrocatalysts for CO2 are summarized through the following stages: first, brief fundamentals of electrochemical CO2 reduction reaction (CO2RR) and a concise introduction of POMs are introduced to provide a preliminary understanding of POM-based electrocatalysts for CO2RR; next a chronology is retrospected with respect to the development of POM-based electrocatalysts for CO2RR; subsequently, representative works are demonstrated based on the POMs themselves and POM-modified metals/alloys, and molecular catalysts as CO2RR electrocatalysts. Finally, perspectives are proposed for the challenges of the design and development of POM-based systems for electrochemical CO2RR.
Nondestructive mixing characteristics of optical resonance modes investigated using artificial dielectric systems
Authors: Tokuda Yasunori , Sakaguchi Koichiro , Watanabe Shogo , Nakajima Makoto , Akiyama Koichi
Published: December 2020

The nondestructive mixing properties of optical resonance modes were investigated using a structure with a dielectric sandwiched between metallic sub-wavelength cut-through slit-array slabs. For the un-shifted slit-array configuration, the resonance mode repulsion around the intersection was more enhanced for an intermediate dielectric with a greater refractive index, though no anticrossing characteristic was seen for an air-gap structure. On the other hand, a lateral shift of the slit arrays enhanced the mode mixing effects even for an air-gap structure. The geometrically dependent characteristics are interpreted in terms of the difference between the (effective) refractive indices of both sides of the slits.
Study on vorticity diffusion laws under oscillating flow and its influences on dissipation loss
Authors: Zhang Bilin , Liu Meng , Tang Yuming , Wang Huanguang
Published: December 2020

In this paper, the vorticity-stream function method is proposed to study the incompressible oscillating flow in the channel of Stirling regenerators. The vorticity field and velocity field in the channels of the parallel-plate regenerator are investigated. The plate spacing and oscillating frequency and kinematic viscosity of the working medium are unified as a dimensionless number e. The results showed that when e is ∼7, the “velocity overshoot” phenomenon occurs in the flow field, and this phenomenon becomes more evident with the increase of e and it gradually approaches the wall of the channel. The phase relationship between the pressure drop and the flow rate was obtained; the results showed that the phase of the flow rate lags behind the pressure drop, and the phase difference is influenced by spacing, frequency, and kinematic viscosity, with the maximal phase difference being 90°. The viscous dissipation loss in the channel was obtained based on the characteristic relationship between the cumulative flow and the pressure drop, and the wasted power of helium crossing a single channel was calculated to be less than 50 W when the frequency is no more than 100 Hz and the plate spacing is greater than 0.5 mm (given a swept volume of 500 ml). The results obtained in this paper verified the application of the vorticity-stream function method in oscillating flows, and the advantage of low resistance of helium over nitrogen was theoretically demonstrated in the relatively high frequency range.
Analysis on longitudinal vibration law of deep sea stepped mining pipe
Authors: Xiao Lin-jing , Liu Qiang , Lu Ji-ming
Published: December 2020

In order to study the longitudinal vibration law of the deep sea stepped mining pipe, the pipe is regarded as the beam element and discrete by the finite element method and the mathematical model is established. Based on the Wilson-θ integration method, the numerical calculation is performed and the longitudinal vibration law under different pipe lengths, pipe thicknesses, and towing speeds is obtained. The research shows that the vibration is the irregular oscillating motion, and the law of the vibration amplitude from the top to the bottom is to decrease first and then to increase. Under the same working conditions, increasing the total length of the mining pipe, the pipe thickness, and the towing speed will reduce the amplitude of the longitudinal vibration, but only when the total length of the pipe changes, will the position of the minimum vibration amplitude be changed. The pipe thickness and the towing speed cannot change the vibration frequency, while the pipe length can change the vibration frequency. When the same external damping is added, reducing the pipe length, pipe thickness, and towing speed will increase the vibration intensity attenuation value and enhance the damping effect.
Simultaneous imaging and manipulation of microparticles in horizontal and vertical planes of microchannels using a single objective lens
Authors: Lei Junjun , Cheng Feng , Li Kemin , Liu Guotian , Zhang Yongjun , Guo Zhongning , Zhang Yongkang
Published: December 2020

In this Letter, we present an experimental method that allows simultaneous imaging of microparticles in horizontal and vertical planes of a microchannel using a single objective lens to be achieved. This is done by implementing a specialized dual-prism arrangement, i.e., by placing two 67.5° right triangular prisms between the objective and the microfluidic channel. Apart from demonstrating simultaneous imaging of microparticles in orthogonal planes of a microchannel and discussing the applicability of the dual-prism configuration for efficient microchannel imaging, examples are also given for the imaging of microparticle alignment and motion in an acousto-microfluidic channel, where microparticles were found to be rapidly focused to the channel center under ultrasonic excitations. It is demonstrated here that, compared to the optical measurements using conventional microscopy, which generally can only ensure one plane of a microchannel in focus, the optical platform presented here enables more convenient and superior optical characterization of microparticles and acoustophoresis.
High radiation dose rates may improve cancer therapy
Authors: Feder Toni
Published: December 2020

The ill-understood effect is gaining momentum and opening new avenues of research. CERN’s Compact Linear Collider and other particle accelerators are contributing.
Spectrally selective fundamental core mode suppression in optical fibre containing absorbing rods
Authors: Aleshkina S.S. , Kashaykina T.A. , Yashkov M.V. , Salganskii M.Yu. , Alyshev S.V. , Bubnov M.M. , Guryanov A.N. , Likhachev M.E.
Published: December 2020

The feasibility of making a wavelength-selective fibre filter using fibre with absorbing rods in its silica cladding has been demonstrated theoretically for the first time. The technique described in this paper is of great practical interest for designing fibre lasers and amplifiers emitting at wavelengths where lasing is impeded by the presence of more energetically favourable radiative transitions in the active medium. In addition, the approach proposed here can be used for stimulated Raman scattering suppression. The unique feature of the fundamental core mode suppression mechanism examined is that there is a (bending) controlled spectral width of a region where excess losses are produced.
Multiple origins of obligate nematode and insect symbionts by a clade of bacteria closely related to plant pathogens
Authors: Martinson Vincent G. , Gawryluk Ryan M. R. , Gowen Brent E. , Curtis Caitlin I. , Jaenike John , Perlman Steve J.
Published: December 2020

Significance

Obligate symbioses are intimate associations between species in which neither partner can live without the other. It is challenging to study how obligate symbioses arise because they are often ancient and it is difficult to uncover early or intermediate stages. We have discovered a nascent obligate symbiosis involvingHowardula aoronymphium, a well-studied nematode parasite ofDrosophilaflies, and a bacterium related toPectobacterium, a lineage of plant pathogens. Moreover, this nematode symbiont is a member of a widespread group of invertebrate host-associated microbes that has independently given rise to at least four obligate symbioses in nematodes and insects, making it an exciting model to study transitions to obligate symbiosis.
Scaffold association factor B (SAFB) is required for expression of prenyltransferases and RAS membrane association
Authors: Zhou Mo , Kuruvilla Leena , Shi Xiarong , Viviano Stephen , Ahearn Ian M. , Amendola Caroline R. , Su Wenjuan , Badri Sana , Mahaffey James , Fehrenbacher Nicole , Skok Jane , Schlessinger Joseph , Turk Benjamin E. , Calderwood David A. , Philips Mark R.
Published: December 2020

Inhibiting membrane association of RAS has long been considered a rational approach to anticancer therapy, which led to the development of farnesyltransferase inhibitors (FTIs). However, FTIs proved ineffective againstKRAS-driven tumors. To reveal alternative therapeutic strategies, we carried out a genome-wide CRISPR-Cas9 screen designed to identify genes required for KRAS4B membrane association. We identified five enzymes in the prenylation pathway and SAFB, a nuclear protein with both DNA and RNA binding domains. SilencingSAFBled to marked mislocalization of all RAS isoforms as well as RAP1A but not RAB7A, a pattern that phenocopied silencingFNTA, the prenyltransferase α subunit shared by farnesyltransferase and geranylgeranyltransferase type I. We found that SAFB promoted RAS membrane association by controlling FNTA expression.SAFBknockdown decreased GTP loading of RAS, abrogated alternative prenylation, and sensitizedRAS-mutant cells to growth inhibition by FTI. Our work establishes the prenylation pathway as paramount in KRAS membrane association, reveals a regulator of prenyltransferase expression, and suggests that reduction in FNTA expression may enhance the efficacy of FTIs.
Hierarchical supramolecular assembly of a single peptoid polymer into a planar nanobrush with two distinct molecular packing motifs
Authors: Sun Jing , Wang Zhiwei , Zhu Chenhui , Wang Meiyao , Shi Zhekun , Wei Yuhan , Fu Xiaohui , Chen Xuesi , Zuckermann Ronald N.
Published: December 2020

Significance

The preparation of hierarchical biomimetic nanostructures remains a challenging task. Bioinspired peptoid polymers offer a promising opportunity to encode assembly information within the component chains. Here, we report a one-pot preparation of planar nanobrush structures from poly(ethyleneglycol)-
block
-poly(
N
-octylglycine) based on tuning the interplay of crystallization and solvophobicity. Each nanobrush assembly is composed of two distinct structural domains, which form sequentially by control of the solution temperature, and contain distinct molecular packing motifs. Micellar intermediates first assemble into linear arrays at elevated temperature in a mesophase state, followed by lateral, crystallization-driven growth in a living manner upon cooling. Precise control over the nanobrush dimensions could be achieved. The structural tunability and excellent biocompatibility of polypeptoids offer great potential for nanomaterials inaccessible previously.
A highly immunogenic and effective measles virus-based Th1-biased COVID-19 vaccine
Authors: Hörner Cindy , Schürmann Christoph , Auste Arne , Ebenig Aileen , Muraleedharan Samada , Dinnon Kenneth H. , Scholz Tatjana , Herrmann Maike , Schnierle Barbara S. , Baric Ralph S. , Mühlebach Michael D.
Published: December 2020

Significance

The COVID-19 pandemic has already caused over 1 million deaths. Therefore, effective vaccine concepts are urgently needed. In search of such a concept, we have analyzed a measles virus-based vaccine candidate targeting SARS-CoV-2. Using this well-known, safe vaccine backbone, we demonstrate here induction of functional immune responses in both arms of adaptive immunity, yielding antiviral efficacy in vivo with the desired immune bias. Consequently, no immunopathologies became evident during challenge experiments. Moreover, the candidate still induces immunity against the measles, recognized as a looming second menace, when countries are forced to stop routine vaccination campaigns in the face of COVID-19. Thus, a bivalent measles-based COVID-19 vaccine could be the solution for two significant public health threats.
The Fast Track intervention’s impact on behaviors of despair in adolescence and young adulthood
Authors: Godwin Jennifer W. ,   Conduct Problems Prevention Research Group, Bierman Karen L. , Coie John D. , Crowley Daniel M. , Dodge Kenneth A. , Greenberg Mark T. , Lochman John E. , McMahon Robert J. , Pinderhughes Ellen E.
Published: December 2020

Significance

Mortality among young adults (age 25 to 44) is rising due in part to preventable, self-inflicted deaths from suicide, alcohol-related liver disease, and drug overdose. This study finds that a comprehensive childhood intervention (Fast Track) designed to reduce conduct problems in at-risk children also reduces the probability of exhibiting adolescent and young adulthood behaviors that precede these deaths, including suicidal ideation and hazardous drinking as well as opioid use in young adulthood. Intervention-driven improvements in children’s interpersonal, intrapersonal, and academic skills in elementary and middle school partially mediate the direct intervention effect on adolescent and young adult behaviors of despair with a strong indirect pathway through earlier acquisition of interpersonal skills.
HSATII RNA is induced via a noncanonical ATM-regulated DNA damage response pathway and promotes tumor cell proliferation and movement
Authors: Nogalski Maciej T. , Shenk Thomas
Published: December 2020

Significance

HSATII RNA is associated with cancer progression and immunostimulation, and as we recently reported, it plays an important role in herpesvirus infections. However, our understanding of cellular processes responsible for the expression of HSATII RNA is limited. Our current investigation identified a noncanonical, ATM kinase-independent DNA damage response pathway as a common cellular mechanism regulating HSATII RNA induction in virus-infected cells or cells treated with DNA-damaging agents. Additionally, our study provides a link between expression of HSATII RNA and the cellular growth and migration phenotypes of cancer cells, establishing a paradigm to study the biological consequences of HSATII RNA expression, i.e., treatment of normal diploid and tumor cells with DNA-damaging agents.
Radiation with reticulation marks the origin of a major malaria vector
Authors: Small Scott T. , Labbé Frédéric , Lobo Neil F. , Koekemoer Lizette L. , Sikaala Chadwick H. , Neafsey Daniel E. , Hahn Matthew W. , Fontaine Michael C. , Besansky Nora J.
Published: December 2020

Significance

Introgressive hybridization is prevalent in recent and rapid animal radiations, and emerging evidence suggests that it leads to the sharing of genetic variation that can facilitate adaptation to new environments and generate novel phenotypes. Here we study a recent and rapid radiation of African mosquitoes in which only one species,
An. funestus
, is a primary human malaria vector with a continent-wide geographic distribution. We trace the evolutionary history of the group and demonstrate introgression events between multiple species, the most recent of which involved substantial gene flow into
An. funestus
that preceded its range expansion across tropical Africa. Our findings point to introgression as an underappreciated factor contributing to the acquisition of high malaria vectorial capacity.
Essentials of the unityp research project
Authors: Seiler (†) Hansjakob , Ono Yoshiko , Premper Waldfried
Published: December 2020

This contribution surveys the insights of ‘unityp’ (Language Universals and Typology), a research project initiated and led by Hansjakob Seiler from 1973 until 1992 and further developed by him until 2017. First, an overview of essential concepts and the architecture of the unityp model is given. Of central importance are three levels of research: cognitive-conceptual, general comparative grammar, and individual languages. Then the conceptual and methodological implications are demonstrated by selected analyses. These comprise a summary of Seiler’s latest ‘works in progress’ concerning Identification as well as an application of the crucial abductive method in cross-linguistic investigation, exemplified by the object relation and number.
Verbal vs. nominal reflexive constructions
Authors: Puddu Nicoletta
Published: December 2020

Reflexives have been extensively studied from different approaches and perspectives, but no clear consensus has been established on the criteria for their definition. From a morphological point of view, a distinction between nominal reflexives and verbal reflexives has been generally accepted in both functional and generative approaches. However, it is ultimately hard to make a precise distinction between verbal and nominal reflexives which should possibly be viewed as a continuum rather than as a discrete partition. In this paper, I will discuss the opportunity of a categorial distinction between verbal and nominal reflexive constructions, identifying some general principles which allow us to classify a form as “verbal” or “nominal”.
The category ‘pronoun’ in East and Southeast Asian languages, with a focus on Japanese
Authors: Da Milano Federica
Published: December 2020

The topic of the paper is an analysis of the debated notion of the category ‘pronoun’ in East and Southeast Asian languages, with a special focus on Japanese. After a description of the main aspects of the notion of ‘person’ as a grammatical category, the focus is devoted to personal pronouns in general and then to personal pronouns in East and Southeast Asian languages. Special attention is devoted to Japanese personal pronouns, taking into account the Emancipatory Pragmatics approach.
Effects of the interfacial states on the spin-dependent tunneling of Mn3Al-based magnetic tunnel junction
Authors: Qiu Minzheng , Ye Shizhuo , Wang Wei , He Jin , Chang Sheng , Wang Hao , Huang Qijun
Published: December 2020

The study of antiferromagnets (AFMs) has become one of the hotspots of spintronics because of their strong environmental adaptability; however, their magnetic ordering structure limits their practical application. The compensated ferrimagnet Mn3Al has the characteristics of an AFM and the magnetic moment can be controlled by a magnetic field. The successful synthesis of Mn3Al, which possesses a high Curie temperature (605 K), may lead to new applications in spintronics devices. In this work, the electronic structure of free Mn3Al (001) surfaces and the interface effects of the Mn3Al electrode and the GaAs tunnel barrier in the magnetic tunnel junction (MTJ) are investigated with the non-equilibrium Green’s function method. Although redistribution of the partial density of states between the surface and bulk is observed for the two different types of Mn3Al surfaces, the half-metallicity is retained for both the surface structures. Due to the half-metallicity of the surfaces, the tunneling magnetoresistance (TMR) of the MTJ reaches up to 107%. Moreover, the TMR dependence on the GaAs barrier thickness as well as the interface is studied. Through the visual display of the interface states, we find that the interface states can promote electron tunneling in the antiparallel configuration. The high TMR can be maintained at a small barrier width owing to the weak interface states. The results are explained with the transmission coefficient in reciprocal space. This work provides some physical insight for the design and implementation of Mn3Al-based MTJs.
Observing the magnetization reversal processes and anisotropic effective damping of epitaxial FeSi/MgO (001)
Authors: Guo X B , Jiang Y P , Lu X L , Tang X G , Tang Z H , Liu Q X , Li W H , Zuo Y L , Xi L
Published: December 2020

Epitaxial FeSi film on MgO (001) substrate was fabricated via a radio frequency magnetron sputtering technology. The epitaxial relationship of FeSi(001)/[110]//MgO(001)/[100] was characterized by crystal structure measurements and confirmed by in-plane biaxial magnetic anisotropy through vibrating sample magnetometer (VSM). By measuring Kerr magnetic hysteresis loops and recording the real-time magnetic domain images through surface magneto-optic Kerr effect (MOKE), two successive 90° domain wall displacement along easy axis and two discontinuous 90° domain wall displacement along hard axis were directly observed. Meanwhile, the difference of magnetic hysteresis loops obtained by VSM and MOKE devices were discussed. Furthermore, from the results of magnetic field sweeping ferromagnetic resonance measurements, it was found that FeSi film possesses an anisotropic effective damping constant of 0.0042 for easy axis direction and 0.0053 for hard axis direction, which was ascribed to the crystallographic defects induced two magnon scattering contributions.
Calibration methodology for contact heat flux sensors with enhanced accuracy
Authors: Rizzo G , Christen R , Stöck M
Published: December 2020

This paper presents a method for the calibration of contact heat flow sensors and the measures taken to improve the overall standard uncertainty of the measurements. This may be particularly relevant for applications such as the thermal characterization of Li-ion battery cells, where small amounts of transferred heat must be measured. The designed calibration set-up is based on the measurement of temperature gradients within a reference object, which is a common and well known approach. However, certain aspects must be considered in order to obtain accurate results. In this paper all steps taken to improve the overall measurement uncertainty are described. One of the most important characteristics of the presented methodology is the experimental determination of an equivalent thermal conductivity of the used reference object. To do so, a single-sided guarded hot plate apparatus is integrated into the calibration set-up to generate a precisely known heat flow. This approach is comparable to the determination of the ‘energy equivalent’ in calorimeters. The measured equivalent thermal conductivity agrees well to literature values, but the achieved standard uncertainty is significantly lower. By way of example, the calibration method is applied on a thermoelectric generator, where the temperature dependent sensitivity and the Seebeck coefficient are determined and compared to literature values. The average standard uncertainty of the sensor sensitivity is ±1.86%, which is lower than most results published in the literature. At 20 °C the absolute value of the determined Seebeck coefficient of the examined thermoelectric element is only 2.7% higher than the value expected for the used material (

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The 3D reconstruction method of a line-structured light vision sensor based on composite depth images
Authors: Wang Jiahao , Zhou Zhehai
Published: December 2020

In order to simplify the three-dimensional (3D) reconstruction process of a rotating scanning line-structured light vision sensor, a 3D reconstruction method of composite depth images is proposed. First, a frame of an image acquired by a camera at a constant speed is converted into a column of data in the composite pixel image. Second, the composite pixel image is transformed into a depth image via coordinate transformation. Finally, the 3D coordinates of the object are calculated from the depth image by perspective transformation. The parameters of the light plane are calibrated by using a one-dimensional target, and the focal length of the depth image is calibrated by using a ball target. Compared with the traditional 3D reconstruction method of a structured light vision sensor, this method uses a composite depth image instead of point cloud splicing, which is simple to operate and flexible to calibrate, and further improves the efficiency of the 3D reconstruction of a structured light vision sensor. Experiments show that the absolute error of the 3D measurement in the measurement range of 380–4000 mm is less than 0.21 mm, and the accuracy is higher than 0.26%, which significantly improves the measurement efficiency and point cloud density of the system, and can meet the general 3D reconstruction requirements of the scene.
MoO2@C modified separator as an interlayer for high performance lithium–sulfur batteries
Authors: Li Qian , Wang Yasai , Wang Yang , Yang Liwen , Chen Yanxiao , Guo Xiaodong , Wu Zhenguo , Zhong Benhe , Xiang Wei
Published: December 2020

Lithium–sulfur batteries have attracted much attention as a promising next-generation energy storage system due to their high theoretical specific capacity and energy density. However, lithium–sulfur batteries are still facing some problems that hinder their large-scale commercial application. High conductivity molybdenum dioxide coated with carbon composite (MoO2@C) were introduced to coat the separator to study its application in lithium sulfur batteries. Molybdenum dioxide coated with carbon composite nanoparticles were synthesized by hydrothermal method and high-temperature calcination and then was coated on the separator with acetylene black. The coating layer can take advantage of the synergetic effect of physical barrier and chemical adsorption to reduce the loss of active substances. The electrochemical performance of the battery has been improved by applying MoO2@C in lithium–sulfur separator. The first discharge specific capacity is 917 mA h g−1 under the current density of 1.0 A g−1, after 300 cycles, the capacity is 618 mA h g−1; after 200 cycles under the current density of 2.0 A g−1, the reversible specific capacity can still maintain 551 mA h g−1.
Hole transport free flexible perovskite solar cells with cost-effective carbon electrodes
Authors: Xie Haixia , Yin Xingtian , Guo Yuxiao , Liu Dan , Liang Tong , Wang Gangfeng , Que Wenxiu
Published: December 2020

Low temperature derived carbon electrodes are employed to fabricate low cost hole transport layer free perovskite solar cells, in which perovskite films annealed in glovebox and ambient air are used as the absorbers, respectively. Results suggest that the air annealed sample has bigger crystal grains and higher crystallinity, and the existence of a small amount of lead iodide which passivates grain boundaries contributes to a lower trap density. As a result, a maximum power conversion efficiency (PCE) of 13.07% was obtained on the air annealed device, which is higher than those of devices annealed in glovebox (11.25%). Furthermore, the stability of unencapsulated devices stored in wet (with humidity around 90% ± 5%) air atmosphere are investigated and the results prove that our devices exhibit good stability. In addition to rigid devices, flexible perovskite solar cells are also fabricated using the same procedure. The highest PCE of 11.53% is demonstrated on the champion flexible device, and 69% of its initial PCE can be maintained even after 2000 bending cycles with a bending radius of 2 mm. Our work provides a promising and simple rout for low-cost, air-stable, high-efficiency carbon perovskite solar cells for both large area production and flexible electronic devices industry.
Dynamics of momentum distribution and structure factor in a weakly interacting Bose gas with a periodical modulation
Authors: Liu Ning , Tu Z C
Published: December 2020

The momentum distribution and dynamical structure factor in a weakly interacting Bose gas with a time-dependent periodic modulation in terms of the Bogoliubov treatment are investigated. The evolution equation related to the Bogoliubov weights happens to be a solvable Mathieu equation when the coupling strength is periodically modulated. An exact relation between the time derivatives of momentum distribution and dynamical structure factor is derived, which indicates that the single-particle property is strongly related to the two-body property in the evolutions of Bose–Einstein condensates. It is found that the momentum distribution and dynamical structure factor cannot display periodical behavior. For stable dynamics, some particular peaks in the curves of momentum distribution and dynamical structure factor appear synchronously, which is consistent with the derivative relation.
Soliton and other solutions to the (1 + 2)-dimensional chiral nonlinear Schrödinger equation
Authors: Hosseini K , Mirzazadeh M
Published: December 2020

The (1 + 2)-dimensional chiral nonlinear Schrödinger equation (2D-CNLSE) as a nonlinear evolution equation is considered and studied in a detailed manner. To this end, a complex transform is firstly adopted to arrive at the real and imaginary parts of the model, and then, the modified Jacobi elliptic expansion method is formally utilized to derive soliton and other solutions of the 2D-CNLSE. The exact solutions presented in this paper can be classified as topological and nontopological solitons as well as Jacobi elliptic function solutions.
Novel localized wave solutions of the (2+1)-dimensional Boiti–Leon–Manna–Pempinelli equation
Authors: Sun Li , Qi Jiaxin , An Hongli
Published: December 2020

Based on a special transformation that we introduce, theN-soliton solution of the (2+1)-dimensional Boiti–Leon–Manna–Pempinelli equation is constructed. By applying the long wave limit and restricting certain conjugation conditions to the related solitons, some novel localized wave solutions are obtained, which contain higher-order breathers and lumps as well as their interactions. In particular, by choosing appropriate parameters involved in theN-solitons, two interaction solutions mixed by a bell-shaped soliton and one breather or by a bell-shaped soliton and one lump are constructed from the 3-soliton solution. Five solutions including two breathers, two lumps, and interaction solutions between one breather and two bell-shaped solitons, one breather and one lump, or one lump and two bell-shaped solitons are constructed from the 4-soliton solution. Five interaction solutions mixed by one breather/lump and three bell-shaped solitons, two breathers/lumps and a bell-shaped soliton, as well as mixing with one lump, one breather and a bell-shaped soliton are constructed from the 5-soliton solution. To study the behaviors that the obtained interaction solutions may have, we present some illustrative numerical simulations, which demonstrate that the choice of the parameters has a great impacts on the types of the solutions and their propagation properties. The method proposed can be effectively used to construct localized interaction solutions of many nonlinear evolution equations. The results obtained may help related experts to understand and study the interaction phenomena of nonlinear localized waves during propagations.
Discrete wavelet structure and discrete energy of classical plane light waves
Authors: Zhang Xing-Chu , She Wei-Long
Published: December 2020

We find by the wavelet transform that the classical plane light wave of linear polarization can be decomposed into a series of discrete Morlet wavelets. In the theoretical frame, the energy of the classical light wave becomes discrete; interestingly, the discretization is consistent with the energy division of P portions in Planck radiation theory, where P is an integer. It is shown that the changeable energy of a basic plane light wave packet or wave train is H
0k
= np
0k

ω (n = 1, 2, 3, … k = |
k
|), with discrete wavelet structure parameter n, wave vector
k
and idler frequency ω, and a constant p
0k
. The wave-particle duality from the Mach--Zehnder interference of single photons is simulated by using random basic plane light wave packets.
Wave-activity relation containing wave-basic flow interaction based on decomposition of general potential vorticity*
Authors: Li Na , Ran Ling-Kun , Jiao Bao-Feng
Published: December 2020

On the basis of the general potential vorticity theorem (GPV), a new wave–activity relation is derived in an ageostrophic and nonhydrostatic dynamic framework. When the Reynolds average is taken, the wave–activity relation shares an exchange term with the equation of the basic-state GPV. Thus, the two equations are capable of presenting the dynamic process of the wave–basic flow interaction. Unlike the E–P flux theory which can only be used in large-scale atmosphere, the corresponding derivation provides a useful tool to analyze the feedback of waves to basic states and the forcing of basic states to waves simultaneously, and it can be used in mesoscale systems, such as heavy rainfall processes. The theory was initially applied to the landfalling Typhoon Mujigae (2015) by assigning the scalar φ to the generalized potential temperature (GPT). The results showed that the newly-derived wave–activity density is able to describe the wave activities associated with strong precipitation in Typhoon Mujigae (2015), including the eyewall and spiral rainbands. However, the interaction between the basic-state vortex and mesoscale waves denoted by the exchange term between basic-state GPV and wave–activity density mainly occurs in the eyewall in Typhoon Mujigae (2015). A comparison of the exchange term with other forcing terms in the newly-derived wave–activity relation indicates that the basic state–wave interaction plays a significant role in enhancing wave activities in the high-precipitation eyewall. By a magnitude analysis of the interaction term, it is found that the strong interaction between basic-state vortex and mesoscale waves is mainly attributed to two factors: the vertical vorticity intensity of the basic-state vortex and the averaged perturbation advection of perturbation GPT which is an exchange between the basic-state GPT and perturbation GPT.
Influences of supply voltage on single event upsets and multiple-cell upsets in nanometer SRAM across a wide linear energy transfer range*
Authors: Luo Yin-Yong , Chen Wei , Zhang Feng-Qi , Wang Tan
Published: December 2020

The influences of reducing the supply voltage on single event upset (SEU) and multiple-cell upset (MCU) in two kinds of 65-nm static random access memories (SRAMs) are characterized across a wide linear energy transfer (LET) range. The results show that the influence of the voltage variation on SEU cross section clearly depends on the LET value which is above heavy ion LET threshold no matter whether the SRAM is non-hardened 6T SRAM or radiation-hardened double dual interlocked cells (DICE) SRAM. When the LET value is lower than the LET threshold of MCU, the SEU only manifests single cell upset, the SEU cross section increases with the decrease of voltage. The lower the LET value, the higher the SEU sensitivity to the voltage variation is. Lowering the voltage has no evident influence on SEU cross section while the LET value is above the LET threshold of MCU. Moreover, the reduction of the voltage can result in a decrease in the highest-order MCU event cross section due to the decrease of charge collection efficiency of the outer sub-sensitive volume within a certain voltage range. With further scaling the feature size of devices down, it is suggested that the dependence of SEU on voltage variation should be paid special attention to for heavy ions with very low LET or the other particles with very low energy for nanometer commercial off-the-shelf (COTS) SRAM.