bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnetically targeted erythrocyte membrane coated nanosystem for synergistic photothermal/chemotherapy of cancer
Authors: Wang Long , Chen Sijie , Pei Wenjing , Huang Biying , Niu Chengcheng
Published: April 2020

Combination photothermal therapy (PTT)/chemotherapy has become an emerging cancer treatment strategy in recent years.
Examining Social Communication Effects of a Picture Communication Board in a Child With Autism
Authors: Lesser Jenna , Ebert Kerry Danahy
Published: April 2020

Purpose

Augmentative and alternative communication (AAC) systems have been shown to increase requesting and protesting among minimally verbal children with autism spectrum disorder (ASD). However, there is a lack of research on using AAC to address social communication in ASD. Additionally, most previous research on AAC involves expensive, difficult-to-access technology. Enhanced milieu teaching and joint attention, symbolic play, engagement, and regulation interventions have been combined to successfully improve social communication in ASD. The purpose of this study is to examine the impact of introducing a low-technology, picture-based communication board using enhanced milieu teaching with joint attention, symbolic play, engagement, and regulation on social communication.

Method

An A-B-A-B single-subject design was implemented with a minimally verbal boy with ASD aged 3;4 (years;months). Three baseline sessions were followed by six intervention sessions and then repeated. Outcome measures included frequency of communicative acts, percentage of communication acts using AAC, and percentage of communication acts that were social. Visual analysis in combination with Tau-U effect sizes was used to evaluate the effects of intervention.

Results

Clear and immediate effects on frequency of communication (Tau-U = 0.97) and adoption of the AAC system (Tau-U = 1.00) were observed. The intervention did not clearly impact social communication (Tau-U = 0.17).

Conclusions

This study extends previous research indicating that AAC can quickly increase communication frequency to low-technology, accessible systems. The intervention dosage may have been insufficient to affect social communication, and further research should consider whether picture communication boards can positively influence social communication in young children with ASD.
Peak‐to‐average power ratio reduction in LTE‐advanced systems using low complexity and low delay PTS
Authors: AhmadiMoghaddam Naser , Maleki Alireza , Sharafat Ahmad R.
Published: April 2020

Peak‐to‐average power ratio (PAPR) is the main parameter affecting the implementation cost of wireless transmitters utilising carrier aggregation in the end‐users' channels. In each frequency band, single‐carrier frequency division multiple access (SC‐FDMA) is exploited as the interface from the transmitter to the receiver, and carrier aggregation is implemented by SC‐FDMA on each band. Hence, the power amplifier simultaneously amplifies signals of multiple bands, meaning that its PAPR is affected by the use of multiple SC‐FDMA channels. In this study, a novel method has been proposed for the delay and PAPR reduction in carrier aggregation systems. Also, a novel recursive method is proposed to reduce the computational complexity of the proposed partial transmit sequence (PTS) algorithm. Utilising computer simulations, it has been shown that the PAPR can be reduced by 3.5 dB for the time‐domain PTS method in mapping for the three‐band SC‐FDMA comparing to existing methods.
Reconstruction of the far field radiated by an offset mounted volumetric AUT from non‐redundant spherical spiral near‐field measurements
Authors: D'Agostino Francesco , Ferrara Flaminio , Gennarelli Claudio , Guerriero Rocco , Migliozzi Massimo
Published: April 2020

The theoretical foundations of the near to far field transformation (NTFFT) techniques with spiral scannings have been properly applied to develop a non‐redundant spherical spiral NTFFT which properly accounts for a mounting of a volumetric antenna under test (AUT) in an offset configuration, due to any practical constraints. Such an NTFFT, based on the non‐redundant sampling representations of electromagnetic fields using spherical modelling of the AUT, requires the same number of near‐field (NF) spiral data when the AUT is mounted both in onset and offset configuration because this number depends only on the area of the modelling sphere centred at the AUT centre. Moreover, it employs an efficient two‐dimensional (2D) optimal sampling interpolation (OSI) formula to recover, from the spiral NF samples, the massive number of NF data required by the classical spherical NTFFT, which is related to the radius of the smallest sphere enclosing the AUT and centred at the scanning sphere centre. It is so possible to get a remarkable measurement time saving when the AUT is offset mounted. Numerical and experimental results, fully assessing the effectiveness of the developed NTFFT and the related 2D OSI algorithm, are shown.
Wearable high gain low SAR antenna loaded with backed all‐textile EBG for WBAN applications
Authors: El Atrash Mohamed , Abdalgalil Omar F. , Mahmoud Ibrahim S. , Abdalla Mahmoud A. , Zahran Sherif R.
Published: April 2020

A high gain, low specific absorption rate, oval‐shaped monopole antenna is presented. It is backed by an all‐textile 3 × 3 array of electromagnetic bandgap (EBG) unit cells. The antenna is printed on the thin Rogers ULTRALAM 3850 substrate, while the EBG array is composed of the conductive ShieledIT Super and dielectric substrate felt. The design operates at 2.45 GHz of the Industrial, Scientific, and Medical band. Due to the close distance between the extended grounds of the co‐planar waveguide feeding configuration and the oval‐shaped monopole antenna, current‐coupling was achieved, leading to gain enhancement. However, with body‐loading cases, resonance at 2.45 GHz was attained at a separation of 30 mm. By incorporating the EBG array, as an isolator, this issue was resolved. In free space and over a gap of 3 mm from the human body, gain enhancements by 2.68 and 11.54 dB were achieved at 2.45 GHz, respectively. Simulated and measured results are benchmarked. Furthermore, SAR simulation study showed reductions by 99.5%, averaged over 1 and 10 g of tissue.
Dirac leaky wave antenna for millimetre‐wave applications
Authors: Rezaee Sina , Memarian Mohammad , Eleftheriades George V.
Published: April 2020

Dirac dispersion cones enable remarkable wave phenomena in electronics as well as electromagnetic systems. In this work, the authors experimentally demonstrate for the first time the Dirac leaky wave antennas (DLWAs) at millimetre‐wave (mm‐wave) frequencies. The demonstrated DLWAs are implemented in the substrate integrated waveguide technology, delivering unprecedented features at high frequencies such as radiation at, and continuous beam scanning through broadside, with ease of fabrication, making these designs well suited for mm‐wave applications such as emerging fifth generation and Internet of Things, radar and imaging. It is shown that a planar Dirac photonic crystal can be realised composed of air columns inside a host SIW waveguide, exhibiting a closed bandgap and linear dispersion around broadside. Phase and attenuation constants are controlled to obtain directive beam and scanning in a wide range of angles (from −30° to 20°). The presented DLWAs have a wide impedance bandwidth around 28 GHz with high efficiency, and operate with peak gains of about 16 dBi with <1 dB gain variation throughout the frequency range from 25 to 31 GHz. Several designs have been proposed, and their prototypes were fabricated using standard substrates. Measured results show excellent agreement with the simulated results, validating the proposed concepts.
Sliding mode observer‐based AC voltage sensorless model predictive control for grid‐connected inverters
Authors: Guo Leilei , Li Yanyan , Jin Nan , Dou Zhifeng , Wu Jie
Published: April 2020

Recently, model predictive control has been widely used to control grid‐connected inverters due to its advantages. However, the conventional model predictive control methods usually require two AC voltage and current sensors to sample the grid voltages and currents. Particularly, the DC voltage sensor is also required to calculate the values of the voltage vectors. The inverter will lose its stability once these sensors fail. Thus, in this study, to improve the operational reliability of the grid‐connected inverters, a sliding mode observer‐based AC voltage sensorless model predictive control is proposed. First, a sliding mode observer is designed to estimate the grid voltage. Next, a new adaptive compensation strategy is proposed to remove the phase and amplitude errors caused by the low‐pass filter. The main novelty of this compensation strategy is that it is immune to the actual grid frequency. Therefore, the grid voltage can be identified accurately, even under frequency deviation conditions. Besides, the stability and parameter designing method of the sliding mode observer is also analysed to provide a theoretical basis for its implementation. Finally, based on the observed grid voltage, the AC voltage sensorless model predictive control is achieved. Detailed comparative experimental results show the validity of the proposed method.
The proper motion of sub-populations in ω Centauri
Authors: Sanna N. , Pancino E. , Zocchi A. , Ferraro F. R. , Stetson P. B.
Published: April 2020

The galactic globular cluster ω Centauri is the most massive of its kind, with a complex mix of multiple stellar populations and several kinematic and dynamical peculiarities. Different mean proper motions have been detected among the three main sub-populations, implying that the most metal-rich one is of accreted origin. This particular piece of evidence has been a matter of debate because the available data have either not been sufficiently precise or limited to a small region of the cluster to ultimately confirm or refute the result. Using astrometry from the second Gaia data release and recent high-quality, multi-band photometry, we are now in a position to resolve the controversy. We reproduced the original analysis using the Gaia data and found that the three populations have the same mean proper motion. Thus, there is no need to invoke an accreted origin for the most metal-rich sub-population.
Numerical approximations for a fully fractional Allen–Cahn equation
Authors: Acosta Gabriel , Bersetche Francisco M.
Published: April 2020

A finite element scheme for an entirely fractional Allen–Cahn equation with non-smooth initial data is introduced and analyzed. In the proposed nonlocal model, the Caputo fractional in-time derivative and the fractional Laplacian replace the standard local operators. Piecewise linear finite elements and convolution quadratures are the basic tools involved in the presented numerical method. Error analysis and implementation issues are addressed together with the needed results of regularity for the continuous model. Also, the asymptotic behavior of solutions, for a vanishing fractional parameter and usual derivative in time, is discussed within the framework of the Γ-convergence theory.
Are zygomatic implants a simple and reliable technique for the stabilization of obturator prostheses? Case report and review of the literature
Authors: Sender Benjamin , Lacroix Thibault , Jaby Philippe , Chaux-Bodard Anne-Gaelle
Published: April 2020

Zygomatic implants have been used for several years for the treatment of extremely resorbed maxilla. Indications were extended for oral rehabilitations after maxillectomy in oncologic patients. A 24-year old patient with a triple A syndrome who underwent a left maxillectomy due to a spinocellular tumour was addressed for prosthetic rehabilitation. As his obturator prosthesis failed, surgical closure of the defect combined with 2 zygomatic implants to support the prosthesis was proposed. Despite a small persistent oro-antral fistula, the new obturator prosthesis restored the patient's functions and esthetics and improved his quality of life. The literature reports less than 40 cases of maxillectomy patients rehabilitated with zygomatic implants (with or without flap closure of the defect). Regardless of implant placement, there is no significant difference between reconstructive surgery and obturator prosthesis. Thus, zygomatic implants seem to be a reliable method for the stabilization of obturator prosthesis, without complex surgical procedure. Nonetheless, reservations should be expressed given the lack of data in terms of long-term follow up.
Occurrence of black stem on Helianthus annuus caused by Phoma macdonaldii and resistant evaluation of different sunflower varieties
Authors: Yan Ningning , Na Ren , Jia Ruifang , Zhang Jian , Zhao Jun
Published: April 2020

The first reported case of Phoma macdonaldii Boerema that caused sunflower black stem disease in China was from Xinjiang Uygur Autonomous Region in 2008. Black spindle lesions were observed on sunflower stems in the fields of Inner Mongolia region in China. The causal agents were isolated from the infected stems. Cultures on potato dextrose agar (PDA) plates were whitish with black particles underneath. Dark and pear-like pycnidia with yellowish or dirty whitish exudates were also observed on the surface of the cultures. The cultures produce primarily non-septate conidia. The cultures could infect sunflowers stems by artificial inoculation and developed symptoms consistent with those in the field. Morphological characteristics and molecular identification indicated the isolated causal agents were P. macdonaldii. Phylogenetic analysis based on ITS1, 5.8 s RNA and ITS2 region confirmed the identification. Disease resistance assessments were performed on twenty sunflower varieties and the results suggested that the resistance of seven sunflower varieties to P. macdonaldii was above the average; SC89 and Longkuiza1 were susceptible to P. macdonaldii.
Interactions of solitary waves in integrable and nonintegrable lattices
Authors: Deng Guo , Biondini Gino , Sen Surajit
Published: April 2020

We study how the dynamics of solitary wave (SW) interactions in integrable systems is different from that in nonintegrable systems in the context of crossing of two identical SWs in the (integrable) Toda and the (non-integrable) Hertz systems. We show that the collision process in the Toda system is perfectly symmetric about the collision point, whereas in the Hertz system, the collision process involves more complex dynamics. The symmetry in the Toda system forbids the formation of secondary SWs (SSWs), while the absence of symmetry in the Hertz system allows the generation of SSWs. We next show why the experimentally observed by-products of SW–SW interactions, the SSWs, must form in the Hertz system. We present quantitative estimations of the amount of energy that transfers from the SW after collision to the SSWs using (i) dynamical simulations, (ii) a phenomenological approach using energy and momentum conservation, and (iii) using an analytical solution introduced earlier to describe the SW in the Hertz system. We show that all three approaches lead to reliable estimations of the energy in the SSWs.
Shape anisotropy effects on spin-torque oscillators
Authors: Chao Xiaohui , Jamali Mahdi , Wang Jian-Ping
Published: April 2020

Spin-torque oscillators are promising candidates for hard disk drive read head sensors, neuromorphic computing, and telecommunications due to their frequency tunability by a direct current or a magnetic field. A narrow linewidth and a large quality factor are of great importance for these applications. Previous studies have indicated that the spin-torque oscillation linewidth depends on the temperature, current, and in-plane field angle. Here, we have investigated the spin-torque oscillations in MgO-based magnetic tunnel junctions (MTJs) and demonstrated the impact of the MTJ shape anisotropy on the threshold current. Our experimental results suggest that due to different threshold currents, the linewidth is different in the MTJs with different shape anisotropy, which might be significant for device optimization.
Quo vadis, perovskite emitters?
Authors: Sum Tze Chien , Righetto Marcello , Lim Swee Sien
Published: April 2020

Halide perovskites hold great promise for next generation printable optoelectronic devices. Within a decade of their debut in photovoltaics, these amazing materials proliferate beyond solar cells to applications such as light-emitting devices, lasers, radiation detectors, and memristors. Such versatility stems from perovskites’ favorable optoelectronic properties that are highly exceptional for a facile solution-processed system. Halide perovskite emitters have made significant inroads, in particular, perovskite light emitting device (PeLED) efficiencies have risen from <1% to >20% within 5 years, and perovskite continuous wave amplified spontaneous emission has also been demonstrated recently. This perspective distills the photophysical mechanisms underpinning the various approaches in enhancing their radiative efficiencies. Selected works are highlighted to detail the milestones and to chart the direction the field is heading. Challenges and opportunities for solid-state PeLEDs are discussed. A clear understanding of their basic photophysics and structure-function relations holds the key to rationalizing strategies and streamlining efforts to realize high efficiency PeLEDs and perovskite lasers.
The effect of dust grains on the Weibel instability in presence of large amplitude electrostatic waves
Authors: Gahlot Ajay , Sharma Suresh C. , Sharma Jyotsna
Published: April 2020

Theoretical investigations on the effect of dust charge fluctuations on Weibel instability in a plasma, with an electron beam in the presence of large amplitude electrostatic Langmuir waves, have been performed. It is observed that the dust charge fluctuations enhance the growth rate of electromagnetic (EM) perturbations. An increase in the electron to ion temperature ratio amplifies the EM perturbations, leading to an enhanced magnetic field due to Weibel instability. It has been found that the growth rate of Weibel instability strongly depends on the dust grain size for different values of ion to electron density ratio δm. Moreover, the electron to ion temperature ratio also destabilizes the Weibel instability.
Modification of magnetocrystalline anisotropy via ion-implantation
Authors: Lee Michael S. , Chopdekar Rajesh V. , Shafer Padraic , Arenholz Elke , Takamura Yayoi
Published: April 2020

The ability to systematically modify the magnetic properties of epitaxial La0.7Sr0.3MnO3 thin films is demonstrated through the use of Ar+ ion implantation. With increasing implant dose, a uniaxial expansion of the c-axis of the unit cell leads to a transition from in-plane toward perpendicular magnetic anisotropy. Above a critical dose of 3 × 1013 Ar+/cm2, significant crystalline disorder exists leading to a decrease in the average Mn valence state and near complete suppression of magnetization. Combined with lithographic techniques, ion implantation enables the fabrication of magnetic spin textures consisting of adjacent regions with tunable magnetic anisotropy in complex oxide thin films.
Application of dynamic mode decomposition to rotating structures in detached linear plasmas
Authors: Natsume H. , Tanaka H. , Kajita S. , Ohno N.
Published: April 2020

Dynamic mode decomposition (DMD) was applied to time-series snapshots of dynamic behavior in detached plasmas with a fast framing camera in the linear plasma device NAGDIS-II. The DMD extracted radial plasma ejection and Er×B rotation structures, which are associated with blob-like plasma structures. Besides, we investigated the influences from neutral gas pressure on the growth rates of the DMD modes. By increasing the neutral gas flow rate in the detached plasma, the growth rate of rotation mode became larger while the frequency decreased. The results indicated that the ejected plasma existed for a longer time in the periphery region. It is likely due to the fact that the ratio of the radial velocity to the rotation velocity of the ejected plasma decreased.
Cell biomechanics and mechanobiology in bacteria: Challenges and opportunities
Authors: Harper Christine E. , Hernandez Christopher J.
Published: April 2020

Physical forces play a profound role in the survival and function of all known forms of life. Advances in cell biomechanics and mechanobiology have provided key insights into the physiology of eukaryotic organisms, but much less is known about the roles of physical forces in bacterial physiology. This review is an introduction to bacterial mechanics intended for persons familiar with cells and biomechanics in mammalian cells. Bacteria play a major role in human health, either as pathogens or as beneficial commensal organisms within the microbiome. Although bacteria have long been known to be sensitive to their mechanical environment, understanding the effects of physical forces on bacterial physiology has been limited by their small size (∼1 μm). However, advancements in micro- and nano-scale technologies over the past few years have increasingly made it possible to rigorously examine the mechanical stress and strain within individual bacteria. Here, we review the methods currently used to examine bacteria from a mechanical perspective, including the subcellular structures in bacteria and how they differ from those in mammalian cells, as well as micro- and nanomechanical approaches to studying bacteria, and studies showing the effects of physical forces on bacterial physiology. Recent findings indicate a large range in mechanical properties of bacteria and show that physical forces can have a profound effect on bacterial survival, growth, biofilm formation, and resistance to toxins and antibiotics. Advances in the field of bacterial biomechanics have the potential to lead to novel antibacterial strategies, biotechnology approaches, and applications in synthetic biology.
Exchange bias effect in bulk multiferroic BiFe0.5Sc0.5O3
Authors: Fertman E. L. , Fedorchenko A. V. , Desnenko V. A. , Shvartsman V. V. , Lupascu D. C. , Salamon S. , Wende H. , Vaisburd A. I. , Stanulis A. , Ramanauskas R. , Olekhnovich N. M. , Pushkarev A. V. , Radyush Yu. V. , Khalyavin D. D. , Salak A. N.
Published: April 2020

Below the Néel temperature, TN ∼ 220 K, at least two nano-scale antiferromagnetic (AFM) phases coexist in the polar polymorph of the BiFe0.5Sc0.5O3 perovskite; one of these phases is a weak ferromagnetic. Non-uniform structure distortions induced by high-pressure synthesis lead to competing AFM orders and a nano-scale spontaneous magnetic phase separated state of the compound. Interface exchange coupling between the AFM domains and the weak ferromagnetic domains causes unidirectional anisotropy of magnetization, resulting in the exchange bias (EB) effect. The EB field, HEB, and the coercive field strongly depend on temperature and the strength of the cooling magnetic field. HEB increases with an increase in the cooling magnetic field and reaches a maximum value of about 1 kOe at 5 K. The exchange field vanishes above TN with the disappearance of long-range magnetic ordering. The effect is promising for applications in electronics as it is large enough and as it is tunable by temperature and the magnetic field applied during cooling.
Numerical simulation of multiple-current-pulse dielectric barrier discharge with ring electrodes in helium at atmospheric pressure
Authors: Wang Jing , Lei Bingying , Li Jing , Xu Yonggang , Wang Yishan , Tang Jie , Zhao Wei , Duan Yixiang
Published: April 2020

A two-dimensional fluid model was used to investigate the characteristics of a multiple-current-pulse dielectric barrier discharge (DBD) equipped with ring electrodes in helium at atmospheric pressure. The simulation results show that the discharge at peak moment follows the Townsend mode in the DBD with two current pulses in each half cycle. However, when there are three or four current pulses in each half cycle, the discharge mode at the first current peak transforms to the glow mode. Additionally, for the first and third current pulse, the breakdown first occurs in the radial center of the ring electrodes. But for the discharge in the second and fourth current pulse, it ignites from the periphery of the ring electrodes. Moreover, the discharge structure, i.e., the radial spatial distributions of current density, electron density, and electric field at peak moments, shows a feature of alternation between (1) higher current density, electron density, and electric field locating in the radial center of ring electrodes (center-advantage) and (2) higher current density, electron density, and electric field locating in the periphery of ring electrodes (periphery-advantage). This behavior is attributed to the fact that non-uniform surface charge accumulation during the previous discharge has different effects on the electric field in the gas gap in the subsequent discharge.
Instability of an electron-plasma shear layer in an externally imposed strain flow
Authors: Hurst N. C. , Danielson J. R. , Dubin D. H. E. , Surko C. M.
Published: April 2020

The E×B shear instability of a two-dimensional (2D) filament (i.e., a thin, rectangular strip perpendicular to the magnetic field) of magnetized pure electron plasma is investigated experimentally in the presence of an externally imposed strain flow. Data are acquired using a specialized Penning–Malmberg trap in which strain flows can be applied in 2D by biasing segmented electrodes surrounding the plasma. The E×B drift dynamics are well-described by the Drift-Poisson equations, which are isomorphic to the 2D Euler equations describing ideal fluids. Thus, the experimental results correspond to the Rayleigh instability of a shear layer in a 2D ideal fluid, where the electron density is analogous to the fluid vorticity. Shear layers are prepared by stretching initially axisymmetric electron vortices using a strong, applied strain flow. The data at early times are in quantitative agreement with a linear model which extends Rayleigh's work to account for the influence of an external strain flow. In the presence of weak strain, the system approximately maintains a phase relationship that corresponds to an instantaneous Rayleigh eigenmode. The instability develops into the nonlinear regime later in time and at smaller spatial scales as the strain rate is increased. A secondary vortex pairing instability is observed, but it is suppressed when the strain-to-vorticity ratio exceeds roughly 0.025. In this way, vorticity transport perpendicular to the filament is diminished due to the applied strain.
High repetition rate and high power picosecond terahertz parametric amplifier with a KTiOPO4 crystal
Authors: Zhao Gang , Yang Yuting , Huang Yue , Liu Fangming , Feng Liwen , Huang Senlin , Liu Kexin
Published: April 2020

A high repetition rate, high power, and widely tunable THz parametric amplifier (TPA) with a KTiOPO4 crystal has been demonstrated in this work. A peak power of 1.7 kW and an average power of 89 μW have been obtained at a frequency of 5.74 THz and a repetition rate of 10 kHz. The radiation is expected to be Fourier transform limited, with a pulse duration (full width at half maximum, FWHM) of 5.4 ps and a bandwidth (FWHM) of 81 GHz, and has an M2 parameter close to the pump laser. We have also tested the TPA at a repetition rate of 100 kHz, and the results indicate that mW-level (average power) THz radiation output is feasible with a stronger pump laser that is commercially available.
Enhanced performance of InAs/GaAs quantum dot superluminescent diodes by direct Si-doping
Authors: Wang Hong , Lv Zun-Ren , Zhang Zhong-Kai , Ding Yun-Yun , Wang Hao-Miao , Yang Xiao-Guang , Yang Tao
Published: April 2020

It is necessary to improve the output power and spectral width of superluminescent diodes (SLDs) simultaneously. In this paper, we show that both the output power and the spectral width of the SLDs based on InAs/GaAs quantum dots (QDs) can be significantly enhanced by direct Si-doping in the QDs. The maximum output power of the Si-doped QD-SLD reaches 20.5 mW at an injection current of 570 mA, while that of the undoped one with an identical structure is only 17.8 mW at the injection current of 550 mA. Moreover, the broadest spectral width of the doped QD-SLD is 105 nm, while that of the undoped QD-SLD is 93 nm. The enhanced performance of the doped QD-SLDs can be attributed to the direct Si doping that leads to inactivating the nonradiative recombination centers within or near the QDs and provides excess carriers to occupy the higher excited states.
A communication-free WPT system based on transmitter-side hybrid topology switching for battery charging applications
Authors: Li Xiaoming , Yang Lin , Xu Ziwei , Wu Yuanbao , Liu Sheng , Cai Changsong
Published: April 2020

A communication-free wireless power transfer system based on transmitter-side hybrid topology switching for various battery charging applications is proposed in this paper. The method realizes the stable and reliable constant current (CC) and constant voltage (CV) outputs by the inherent characteristics of the designed hybrid topology. Besides, the zero phase angle condition can be obtained, which enhances the power transmission capability and improves system efficiency. The transition point from the CC to CV charging mode is determined by the battery charging voltage, which is estimated in real-time by measuring the root-mean-square value of high-frequency inverter output current. Then, the whole charging process can be operated by the transmitter-side controller; hence, the receiver-side controller is unnecessary. The advantages are that wireless communication links for real-time feedback of charging parameters between the transmitter and receiver are avoided, sophisticated control strategies are no longer required, and a lightweight, miniaturized, and compact receiver is guaranteed. Finally, to verify the effectiveness and practicability of the proposed approach, a confirmatory experimental setup with 80 V charging voltage and 5 A charging current is constructed. The experimental results match the theoretical analysis.
Exciton–polaritons of a 2D semiconductor layer in a cylindrical microcavity
Authors: Gomes José Nuno S. , Trallero-Giner Carlos , Peres Nuno M. R. , Vasilevskiy Mikhail I.
Published: April 2020

We describe exciton–polariton modes formed by the interaction between excitons in a 2D layer of a transition metal dichalcogenide embedded in a cylindrical microcavity and the microcavity photons. For this, an expression for the excitonic susceptibility of a semiconductor disk placed in the symmetry plane perpendicular to the axis of the microcavity is derived. Semiclassical theory provides dispersion relations for the polariton modes, while the quantum-mechanical treatment of a simplified model yields the Hopfield coefficients, measuring the degree of exciton–photon mixing in the coupled modes. The density of states (DOS) and its projection onto the photonic and the excitonic subspaces are calculated, taking monolayer MoS2 embedded in a Si3N4 cylinder as an example. The calculated results demonstrate a strong enhancement for certain frequencies of the total and local DOS (and, consequently, of the spontaneous emission rate of a nearby point emitter, i.e., the Purcell effect) caused by the presence of the 2D layer.
Green’s function of the Smoluchowski equation with reaction sink: Application to geminate and bulk recombination reactions
Authors: Lee Kyusup , Sung Jaeyoung , Choi Cheol Ho , Lee Sangyoub
Published: April 2020

By applying a recently developed solution method for the Fredholm integral equation of the second kind, we obtain an expression for Green’s function of the Smoluchowski equation with a reaction sink. The result is applied to obtain accurate analytical expressions for the time-dependent survival probability of a geminate reactant pair and the rate coefficient of the bulk recombination between reactants undergoing diffusive motions under strong Coulomb interactions. The effects of both repulsive and attractive interactions are considered, and the results are compared with the numerical results obtained by solving the equation for the survival probability and the nonequilibrium pair correlation function. It is shown that the solutions are accurate enough for most reasonable parameter values.
Al
27
NMR chemical shift of Al(OH)4− calculated from first principles: Assessment of error cancellation in chemically distinct reference and target systems
Authors: Martinez-Baez Ernesto , Feng Rulin , Pearce Carolyn I. , Schenter Gregory K. , Clark Aurora E.
Published: April 2020

Predicting accurate nuclear magnetic resonance chemical shieldings relies upon cancellation of different types of errors between the theoretically calculated shielding constant of the analyte of interest and the reference. Often, the intrinsic error in computed shieldings due to basis sets, approximations in the Hamiltonian, description of the wave function, and dynamic effects is nearly identical between the analyte and reference, yet if the electronic structure or sensitivity to local environment differs dramatically, this cannot be taken for granted. Detailed prior work has examined the octahedral trivalent cation Al(H2O)63+, accounting for ab initio intrinsic errors. However, the use of this species as a reference for the chemically distinct tetrahedral anion Al(OH)4− requires an understanding of how these errors cancel in order to define the limits of accurately predicting Al27 chemical shielding in Al(OH)4−. In this work, we estimate the absolute shielding of the Al27 nucleus in Al(OH)4− at the coupled cluster level (515.1 ± 5.3 ppm). Shielding sensitivity to the choice of method approximation and atomic basis sets used has been evaluated. Solvent and thermal effects are assessed through ensemble averaging techniques using ab initio molecular dynamics. The contribution of each type of intrinsic error is assessed for the Al(H2O)63+ and Al(OH)4− ions, revealing significant differences that fundamentally hamper the ability to accurately calculate the Al27 chemical shift of Al(OH)4− from first principles.
Efficient noise reduction for the free induction decay signal from a proton precession magnetometer with time-frequency peak filtering
Authors: Liu Huan , Wang Hongpeng , Bin Junchi , Dong Haobin , Ge Jian , Liu Zheng , Yuan Zhiwen , Zhu Jun , Luan Xinqun
Published: April 2020

The proton precession magnetometer (PPM) is a commonly used device to measure the varying magnetic field. Since the frequency of the PPM sensing free induction decay (FID) signal is proportional to the magnetic field, the signal-to-noise ratio (SNR) is always a critical issue that influences the measurement accuracy severely due to the external interferences such as harmonic noise and random noise. In this study, to boost the SNR of the FID signal, an effective filtering algorithm based on time-frequency peak filtering (TFPF) analyzed with pseudo-Wigner–Ville distribution (PWVD) is proposed. Through pre-treating the collected noisy FID signal with frequency modulation and instantaneous frequency estimation using the peak value of the time-frequency characterization, the embedded noise can be decorrelated and the relative pure FID signal can be detected regardless of the impact of varying noise levels. The superiority of the proposed synaptic noise reduction framework, namely, TFPF-PWVD, was found by comparing it with state-of-the-art approaches under the same conditions. The results illustrated that even though in a strong-noisy scenario, the proposed TFPF-PWVD based approach still achieved the best SNR for the yielded sensing FID and the minimum standard deviation for the observed magnetic field data, which can enhance the geomagnetic measuring performance of a PPM.
X-ray scattering tensor tomography with circular gratings
Authors: Kim Jisoo , Kagias Matias , Marone Federica , Stampanoni Marco
Published: April 2020

Three dimensional (3D) information of the microstructure organization of various relevant materials in industry and nature is fundamental to master the understanding of their macroscopic properties. X-ray scattering tensor tomography provides 3D directional information on unresolved microstructures in large volumes, facilitating the investigation of the microstructural organization in statistically large enough sample portions. However, established acquisition protocols such as scanning small angle x-ray scattering and x-ray grating interferometry require long measurement time. In this Letter, a rapid x-ray scattering tensor tomography acquisition method is proposed. It is based on circular gratings, which provide single-shot 2D-omnidirectional information of the sample scattering properties. The main advantage of the presented method is the reduced data acquisition time compared to the existing protocols for x-ray scattering tensor tomography, paving the way toward rapid time-resolved studies.
SMAUG helps generate infrared spectroscopy data for Hot Jupiter-type exoplanets
Authors: Mandel Savannah
Published: April 2020

A diagnostic tool known as SMAUG allows researchers to gather more precise data on the atmospheric conditions of Hot Jupiter-type exoplanets.
Dynamics of moving contact line on a transversely patterned inclined surface
Authors: Xia Yuting , Qin Jian , Mu Kai
Published: April 2020

We study the dynamics of moving contact lines and film deposition on a chemically patterned plate withdrawn from a liquid bath obliquely. The plate is patterned with transverse stripes and characterized by alternating wettability. We assume that the inclination of the plate is small enough, so lubrication theory can be employed. The finite element method is used to solve the one-dimensional unsteady lubrication equation, and it is combined with the precursor film model and disjoining pressure to realize the moving contact line with finite contact angles. When the width of the strips is relatively large, four typical modes of contact line dynamics are observed as the withdrawal speed of the plate increases. In particular, if the withdrawal speed is smaller than the critical value of the wetting transition on the more wettable strip, the contact line would periodically move between the equilibrium positions of the more wettable and less wettable regions, which is known as a “stick-slip” motion. In accordance with the Cox–Voinov law, a quantitative analysis of the “stick-slip” motion is conducted, which predicts the critical condition of the “stick” process and the relaxation time of the “slip” process. When the stripe width is sufficiently small, the evolution of the contact line and liquid film is similar to that on an equivalent homogeneous substrate, whose contact angle can be predicted via Cassie theory.
Influence of disorder and surface roughness on the electrical and thermal properties of lithiated silicon nanowires
Authors: Bauer Dominik , Luisier Mathieu
Published: April 2020

We use density functional theory and reactive-force-field methods to investigate the electrical and thermal transport properties of long disordered lithiated silicon nanowires. The latter could build the core of future lithium ion batteries with enhanced storage capacity. Due to the amorphous nature of these nanowires, disorder and surface roughness effects inevitably arise, affecting the lithiation process. It is found that the electrical conductivity of the nanowires steadily increases as a function of the lithium concentration, despite the presence of disorder, while the thermal conductivity follows the opposite trend and decreases significantly with reduced heat evacuation capabilities as a consequence. This behavior can be attributed to the influence of Li ions, which on one hand tend to metallize Si nanowires and thus enhance their electron mobility. On the other hand, the random distribution of Li atoms perturbs the phonon propagation through the nanowire, explaining the decrease in thermal conductivity.
Linkage mapping and whole-genome predictions in canola (Brassica napus) subjected to differing temperature treatments
Authors: Koscielny Chadwick B. , Gardner Stuart W. , Technow Frank , Duncan Robert W.
Published: April 2020

Canola (Brassica napus L.) is grown on >8 Mha in Canada and is sensitive to high temperatures; therefore, research on breeding methodologies to improve heat-stress tolerance is warranted. This study utilised a doubled-haploid population created from two parents (PB36 and PB56) that differed in their ability to set seed following growth at high temperatures. The experiment was designed to identify potential quantitative trait loci (QTLs) responsible for conferring tolerance to increased temperatures, and to utilise this population as a test case for evaluating the prospects of whole-genome prediction. The population was phenotyped in a split-plot, randomised complete block experimental design at three locations with two planting-date treatments. The first planting date was during the normal planting period (control), and the second planting was timed to experience increased average temperatures (1.7°C, 2.0°C and 1.2°C) and increased number of days with maximum temperatures above the critical temperature of 29.5°C (4, 12 and 3 days). The stress treatment reduced yield on average by 16.7%. There were 66 QTLs discovered across the nine traits collected. Given the quantitative nature of the traits collected, the ability to use whole-genome prediction was investigated. The prediction accuracies ranged from 0.14 (yield) to 0.66 (1000-seed weight). Prediction had higher accuracy within the stress treatment than within the control treatment for seven of the nine traits, demonstrating that phenotyping within a stress environment can provide valuable data for whole-genome predictions.
Microbial activity and diversity in the rhizosphere soil of the invasive species Zizania latifolia in the wetland of Wuchang Lake, China
Authors: Zhou Baohua , Liu Zhaowen , Yang Guo , He Hui , Liu Haijun
Published: April 2020

Information about the consequences of invasive species overgrowing freshwater wetlands is limited. According to remote sensing data, the invasive species Zizania latifolia spreads at an annual rate of 1.78km2 in the freshwater wetland of Wuchang Lake, China, resulting in wetland loss and degradation due to the overgrowth. This species not only increases soil organic matter, total carbon, total nitrogen, total sulfate, available nitrogen and the C/N ratio in the rhizosphere soil, but also results in increased urease, sucrose and catalase activity, as well as fluorescein diacetate hydrolysis. In this study, we have analysed microbial diversity in rhizosphere soils among different habitat types of Z. latifolia. Microbial communities in different habitats invaded by Z. latifolia differed considerably at the genus level, although all soil samples were predominated by the phyla Proteobacteria, Acidobacteria and Chloroflexi. The dominant bacterial taxa in the rhizosphere soil from the floating blanket included Acidimicrobiales, Thiomonas, Alicyclobacillus, Acetobacteraceae and Acidocella, whereas those in rhizosphere soils from the lake sludge were Acidobacteria, Anaerolineaceae, Bacteroidetes and Nitrospirae. The bacterial community in the rhizosphere soil differed significantly from that in the non-rhizosphere soil. Z. latifolia potentially creates suitable habitats and provides substrate for a unique set of microbes, further facilitating the succession of this species.
Increasing nitrogen removal efficiency by intermittent aeration in partial areas of laboratory-scale vertical flow constructed wetlands
Authors: Chen Chen , Zhang Nannan , Liu Zhe , An Shuqing , Zhao Dehua
Published: April 2020

Intermittent aeration (IA) has been widely used in constructed wetlands (CWs) because it is economical and results in high nitrogen removal efficiency (RE). The aim of this study was to identify whether IA (4hday–1; the recommended frequency according to previous studies) in a partial area (PIA) can improve nitrogen RE compared with IA applied throughout the CW (TIA). Three types of laboratory-scale vertical flow CWs were constructed: PIA, TIA and non-aerated (NA). PIA achieved a higher RE of total nitrogen than TIA and NA (mean RE 60.6 v. 45.2 and 37.4% respectively). In the PIA, the ammonia mono-oxygenase subunit A (amoA) gene was abundant in aerated areas, whereas the nitrate reductase gene narG and nitrite reductase genes nirK and nirS were abundant in anaerobic areas. The results of this study suggest that PIA is an effective strategy for nitrogen removal when applying aeration in CWs because it preserves a constant anaerobic area for denitrification.
New Mochica and the challenge of reviving an extinct
language
Authors: Eloranta Rita , Bartens Angela
Published: April 2020

In this paper, we discuss New Mochica as an
example of language revival. New Mochica is definitely not the
Mochica of the colonial or republican epoch of present-day Peru and
the continuity of an already extinct language can be questioned. Van
Coetsem’s (1988, 2000) framework of language
contact explains why the contribution of the language revivalists’
dominant language, Spanish, has such a powerful impact on New
Mochica, eradicating the central typological features of Mochica. On
the other hand, the groups of language revivalists presented in this
paper explore the linguistic resources at hand in creative ways.
Based on this case study, we propose that language revival should be
studied as distinct from language revitalization (cf. Zuckermann & Walsh,
2011), yet as related to overall processes of language
making (Hüning & Krämer,
2018).
Political boundary spanning: politicians at the interface between collaborative governance and representative democracy
Authors: Sørensen Eva , Hendriks Carolyn M , Hertting Nils , Edelenbos Jurian
Published: April 2020

Research finds that productive interfaces between collaborative and bureaucratic forms of governance hinges on the extent to which public managers act as competent boundary spanners who process information, accommodate communication and align and coordinate behavior, and it seems likely that politicians have an equally important role to play in aligning processes and arenas of collaborative governance with representative democracy. The empirical forms that political boundary making takes are examined in a study of 28 cases of local, regional or national level policy-making in nine Western countries. This study indicates that there is considerable variation in the way politicians perform political boundary spanning particularly with respect to their degree of engagement in collaborative policymaking arenas and the focus of their boundary-spanning activities. Furthermore, the study shows that collaborative governance tends to go best in tandem with representative democracy in those cases where politicians perform both hands off and hands on boundary-spanning activities.