bluuebunny/crossref_metadata_2025 huggingface dataset:
On a topological criterion to select a recurrence threshold
Authors: Andreadis Ioannis , Fragkou Athanasios D. , Karakasidis Theodoros E.
Published: January 2020

In this work, a topological criterion is proposed for selecting a recurrence threshold for constructing a recurrence plot of a time series. It is based on a metric structure of the set of the recurrence plots that is defined by the recurrence plot deviation distance among recurrence plots, introduced in a previous paper by the authors. In this process for a range of threshold values, the corresponding recurrence plots are constructed. Then, a value of the threshold is considered to be optimal when the image of its recurrence plot remains close to images of the other recurrence plots constructed for close values of thresholds based on the topological criterion introduced in the present work. The results are applied both to time series emanating from the Lorenz dynamical system and to Molecular Dynamic simulations.
Reconstructing bifurcation diagrams only from time-series data generated by electronic circuits in discrete-time dynamical systems
Authors: Itoh Y. , Uenohara S. , Adachi M. , Morie T. , Aihara K.
Published: January 2020

Bifurcation-diagram reconstruction estimates various attractors of a system without observing all of them but only from observing several attractors with different parameter values. Therefore, the bifurcation-diagram reconstruction can be used to investigate how attractors change with the parameter values, especially for real-world engineering and physical systems for which only a limited number of attractors can be observed. Although bifurcation diagrams of various systems have been reconstructed from time-series data generated in numerical experiments, the systems that have been targeted for reconstructing bifurcation diagrams from time series measured from physical phenomena so far have only been continuous-time dynamical systems. In this paper, we reconstruct bifurcation diagrams only from time-series data generated by electronic circuits in discrete-time dynamical systems with different parameter values. The generated time-series datasets are perturbed by dynamical noise and contaminated by observational noise. To reconstruct the bifurcation diagrams only from the time-series datasets, we use an extreme learning machine as a time-series predictor because it has a good generalization property. Hereby, we expect that the bifurcation-diagram reconstruction with the extreme learning machine is robust against dynamical noise and observational noise. For quantitatively verifying the robustness, the Lyapunov exponents of the reconstructed bifurcation diagrams are compared with those of the bifurcation diagrams generated in numerical experiments and by the electronic circuits.
Chaotic memetic algorithm and its application for detecting community structure in complex networks
Authors: Zarei Bagher , Meybodi Mohammad Reza , Masoumi Behrooz
Published: January 2020

Community structure is one of the most important topological characteristics of complex networks. Detecting the community structure is a highly challenging problem in analyzing complex networks and it has high significance for understanding the function and organization of complex networks. A wide range of algorithms for this problem uses the maximization of a quality function called modularity. In this paper, a Chaotic Memetic Algorithm is proposed and used to solve the problem of the community structure detection in complex networks. In the proposed algorithm, the combination of the genetic algorithm (global search) and a dedicated local search is used to search the solution space. In addition, to improve the convergence speed and efficiency, in both global search and local search processes, instead of random numbers, chaotic numbers are used. By using chaotic numbers, the population diversity is preserved and it prevents from falling in the local optimum. The experiments on both real-world and synthetic benchmark networks indicate that the proposed algorithm is effective compared with state-of-the-art algorithms.
Photon arrival time tagging with many channels, sub-nanosecond deadtime, very high throughput, and fiber optic remote synchronization
Authors: Wahl Michael , Röhlicke Tino , Kulisch Sebastian , Rohilla Sumeet , Krämer Benedikt , Hocke Andreas C.
Published: January 2020

Time-Correlated Single Photon Counting (TCSPC) and time tagging of individual photon detections are powerful tools in many quantum optical experiments and other areas of applied physics. Using TCSPC, e.g., for the purpose of fluorescence lifetime measurements, is often limited in speed due to dead-time losses and pileup. We show that this limitation can be lifted by reducing the dead-time of the timing electronics to the absolute minimum imposed by the speed of the detector signals while maintaining high temporal resolution. A complementing approach to speedy data acquisition is parallelization by means of simultaneous readout of many detector channels. This puts high demands on the data throughput of the TCSPC system, especially in time tagging of individual photon arrivals. Here, we present a new design approach, supporting up to 16 input channels, an extremely short dead-time of 650 ps, very high time tagging throughput, and a timing resolution of 80 ps. In order to facilitate remote synchronization of multiple such instruments with highest precision, the new TCSPC electronics provide an interface for White Rabbit fiber optic networks. Beside fundamental research in the field of astronomy, such remote synchronization tasks arise routinely in quantum communication networks with node to node distances on the order of tens of kilometers. In addition to showing design features and benchmark results of new TCSPC electronics, we present application results from spectrally resolved and high-speed fluorescence lifetime imaging in medical research. We furthermore show how pulse-pileup occurring in the detector signals at high photon flux can be corrected for and how this data acquisition scheme performs in terms of accuracy and efficiency.
Effect of ambient pressure on spatial structures of electrical exploding aluminum wires in argon gas
Authors: Zhao Junping , Liu Haoyu , Zhang Qianlong , Zhang Qiaogen
Published: January 2020

The experiments demonstrated a strong dependence of the spatial structures of exploding aluminum wires on ambient pressures. Depending on whether having a current pause, electrical explosion of wires processes was classified into two types and analyzed by stage division. Through shadow, schlieren, and interference images, the spatial structures of exploding wires in two breakdown modes (internal and shunting) were observed. It was indicated that the basic difference is the relative positions of the wire core and the plasma channel. The breakdown mode makes a transition from the shunting mode to the internal mode with increasing pressures. Radial positions of the wire core boundary and the shockwave front were determined by comparing shadowgraphs and multi-frame photographs at different moments. The results demonstrated a gradual separation of the wire core and the shockwave, as well as their parabolic expansion trajectories. Furthermore, the average expansion velocity of wire cores decreases from ∼1.41 km/s to ∼0.78 km/s with the pressure varying from 50 kPa to 400 kPa.
Review of the development of copper oxides with titanium dioxide thin-film solar cells
Authors: Sawicka-Chudy Paulina , Sibiński Maciej , Rybak-Wilusz Elżbieta , Cholewa Marian , Wisz Grzegorz , Yavorskyi Rostyslav
Published: January 2020

Copper oxide-titanium dioxide (TiO 2) p–n junctions are promising materials for photovoltaic devices and may reduce production costs due to their low cost and inexpensive production methods compared with silicon solar cells. The present review compares solar cells made with copper oxides combined with TiO 2–TiO 2/Cu 2O and TiO 2/CuO heterojunctions, and “cascade heterojunction systems.” First, we describe the main properties of titanium (iv) dioxide (TiO 2), cuprous oxide (Cu 2O), and cupric oxide (CuO), and their potential applications. Next, we explain the concept of copper oxide and TiO 2 heterojunctions. We summarize and present the photovoltaic characteristics (efficiency, fill factor, circuit current density, and open circuit voltage), thickness, preparation method, and electrode type for solar cells comprising copper oxide and TiO 2. The efficiency of the solar cells ranged from 0.0005% to 1.62%. The thickness of the TiO 2 and cupric oxide layers ranged from 0.06 to 16 µm, and from 0.18 to 1.5 µm, respectively, depending on the fabrication method. Additionally, we review and discuss the available combinations of copper oxide with other materials (Cu 2O with ZnO, CuO with ZnO, and CuO with Si), as well as the effect of the thickness of the copper (i) oxide and copper (ii) oxide on the solar cell performance. Finally, we present aspects to improve the conversion efficiency of heterojunction solar cells with copper oxides combined with TiO 2. This review will be useful for the construction and further development of thin-film solar cells.
Accelerating viscous flow past a wedge
Authors: Xu Ling
Published: January 2020

This paper presents direct numerical simulations of accelerated viscous flow past an infinite wedge with a focus on the effect of the accelerating rate on vortex dynamics and material transport near the wedge tip. The wedge angle ranges π/3 ≤ βπ ≤ 5π/6 and the acceleration rate is 0 ≤ p ≤ 1. Since the wedge is infinite, the inviscid self-similar analysis predicts that the solution of one viscosity at a time is the same as the solution of a different viscosity at a scaled time. This theoretical prediction is numerically verified in the current work. Evolution of the vorticity, streamlines, and streaklines is shown in great detail. In the vorticity field, hierarchical vortex separations at the wedge tip are observed, which associate with multiple circulating regions in the streamlines. We also compare the solution at varying acceleration rates and wedge angles and explore the scaling laws in the solution. Streaklines are used to illustrate material transport in the fluid flow. The streaklines form two spirals, a major one that corresponds to the starting vortex and a second one that appears near the wedge tip. The formation of both the major and secondary spirals are investigated and diagnosed using the strain rate in the fluid flow.
Chemistry under extreme conditions: Pressure evolution of chemical bonding and structure in dense solids
Authors: Yoo Choong-Shik
Published: January 2020

Recent advances in high-pressure technologies and large-scale experimental and computational facilities have enabled scientists, at an unprecedented rate, to discover and predict novel states and materials under the extreme pressure-temperature conditions found in deep, giant-planet interiors. Based on a well-documented body of work in this field of high-pressure research, we elucidate the fundamental principles that govern the chemistry of dense solids under extreme conditions. These include: (i) the pressure-induced evolution of chemical bonding and structure of molecular solids to extended covalent solids, ionic solids and, ultimately, metallic solids, as pressure increases to the terapascal regime; (ii) novel properties and complex transition mechanisms, arising from the subtle balance between electron hybridization (bonding) and electrostatic interaction (packing) in densely packed solids; and (iii) new dense framework solids with high energy densities, and with tunable properties and stabilities under ambient conditions. Examples are taken primarily from low-Z molecular systems that have scientific implications for giant-planet models, condensed materials physics, and solid-state core-electron chemistry.
Beam and installation improvements of the NIO1 ion source
Authors: Cavenago M. , Barbisan M. , Delogu R. , Pimazzoni A. , Poggi C. , Ugoletti M. , Agostini M. , Antoni V. , Baltador C. , Cervaro V. , De Muri M. , Giora D. , Jain P. , Laterza B. , Maero G. , Maniero M. , Martini D. , Minarello A. , Ravarotto D. , Recchia D. , Rizzolo A. , Romé M. , Sartori E. , Sattin M. , Serianni G. , Taccogna F. , Valentino V. , Variale V. , Veltri P.
Published: January 2020

The NIO1 (Negative Ion Optimization phase 1) source can provide continuous beam operation, which is convenient for systematic parameter and equipment studies. Even in the pure volume production regime, the source yield was found to depend on conditioning procedures. Magnetic configuration tests continued adding magnets to the existing setup; the filter field component Bx has been progressively extended to span the −12 to 5 mT range, and as a trend, source performances improved with |Bx|. The progress of camera beam diagnostics and of the quality of the volume-produced H− beam is also shown. The status, off-line results, and reliability of a first NIO1 cesium oven are discussed; other upgrades in preparation (cavity ring down spectrometer, the end calorimeter, and conceptual tests of the energy recovery system) are also listed.
Ab initio calculation of interlayer exchange coupling in Co-based synthetic antiferromagnet with alloy spacer
Authors: Takashima Rina , Tsukagoshi Takayuki , Ishihara Takamitsu , Kai Tadashi
Published: January 2020

Synthetic antiferromagnets (SAF) are widely used in magnetic tunnel junctions in order to reduce the stray field of the pinned layer. In SAF, the antiparallel spin alignment is stabilized by interlayer exchange coupling (IEC) between two ferromagnetic layers that are separated by a spacer layer. The strength of IEC depends on the spacer material. It is known that strong IEC is required for stable operation of magnetic random access memory with a low error rate, and hence a spacer material that shows strong IEC has been highly sought after. In this study, we investigate the IEC of ordered alloy spacers in Co multilayers by ab initio calculations based on density functional theory. We find that the IEC of binary alloy spacers composed of group 8 and 9 elements, namely, RuIr, RuRh, and OsIr, are greater than that of Ru and Ir spacers, which have commonly been used in SAF pinned layers. We also present dependence of IEC strength on the composition ratio of these alloy spacers. The relation between the strength of IEC and the lattice length is discussed.
Heterogeneous recurrence analysis of spatial data
Authors: Yang Hui , Chen Cheng-Bang , Kumara Soundar
Published: January 2020

Nonlinear dynamical systems often generate significant amounts of observational data such as time series, as well as high-dimensional spatial data. To delineate recurrence dynamics in the spatial data, prior efforts either extended the recurrence plot, which is a widely used tool for time series, to a four-dimensional hyperspace or utilized the network approach for recurrence analysis. However, very little has been done to differentiate heterogeneous types of recurrences in the spatial data (e.g., recurrence variations of state transitions in the spatial domain). Therefore, we propose a novel heterogeneous recurrence approach for spatial data analysis. First, spatial data are traversed with the Hilbert Space-Filling Curve to transform the variations of recurrence patterns from the spatial domain to the state-space domain. Second, we design an Iterated Function System to derive the fractal representation for the state-space trajectory of spatial data. Such a fractal representation effectively captures self-similar behaviors of recurrence variations and multi-state transitions in the spatial data. Third, we develop the Heterogeneous Recurrence Quantification Analysis of spatial data. Experimental results in both simulation and real-world case studies show that the proposed approach yields superior performance in the extraction of salient features to characterize and quantify heterogeneous recurrence dynamics in spatial data.
Thermoelectric properties of Janus MXY (M = Pd, Pt; X, Y = S, Se, Te) transition-metal dichalcogenide monolayers from first principles
Authors: Tao Wang-Li , Lan Jun-Qing , Hu Cui-E , Cheng Yan , Zhu Jun , Geng Hua-Yun
Published: January 2020

In this paper, the thermoelectric (TE) properties of Janus MXY monolayers (M = Pd, Pt; X, Y = S, Se, Te) are systematically studied using first principles and the Boltzmann transport theory. The thermal conductivity (k), Seebeck coefficient (S), power factor (PF), and TE figure of merit (ZT) are calculated accurately for various carrier concentrations. The lattice thermal conductivities of these six materials sequentially decrease in the order PtSSe, PtSTe, PtSeTe, PdSSe, PdSTe, and PdSeTe. PdSeTe and PtSeTe monolayers have a high ZT close to one at 300 K. In addition, we predicted the TE properties at high temperatures and found that the maximum ZT (2.54) is achieved for a monolayer of PtSeTe at 900 K. The structural and electronic properties of these six Janus transition-metal dichalcogenide (TMD) monolayers were systematically studied from first principles. Our results show that all six materials are semiconductors with bandgaps between 0.77 eV and 2.26 eV at the Heyd-Scuseria-Ernzerhof (HSE06) level. The present work indicates that the Janus MXY TMD monolayers (M = Pd, Pt; X, Y = S, Se, Te) are potentially TE materials.
Application of localization landscape theory and the k · p model for direct modeling of carrier transport in a type II superlattice InAs/InAsSb photoconductor system
Authors: Tsai Tsung-Yin , Michalczewski Krystian , Martyniuk Piotr , Wu Chao-Hsin , Wu Yuh-Renn
Published: January 2020

Localization landscape (LL) theory is applied to directly model carrier transport in a type II superlattice (T2SL) InAs/InAsSb photoconductor system. It is difficult to apply the classical Poisson and drift–diffusion (DD) model to direct modeling of carrier transport in superlattice systems because quantum effects need to be considered. With the LL theory, it is possible to obtain the effective quantum potential seen by carriers. By coupling the LL theory with the Poisson–DD model and replacing the traditional conduction and valence potentials with effective quantum potentials, it is possible to directly model carrier transport in a T2SL system. We compare the results of this approach with experimental results and find very good agreement, which indicates that this method will provide an efficient tool for the T2SL design.
On the effect of structural disorders on the Urbach’s tails of ternary chalcopyrite semiconductors and related ordered defect compounds
Authors: Wasim Syed M. , Marín Giovanni , Marquez Rigoberto , Rincón Carlos
Published: January 2020

The effect of structural disorders on the Urbach's tails (UTs) in the optical absorption spectra in CuBIIIC2VI, CdBIVC2V ternary chalcopyrite semiconductors and other related CuB3IIIC5VI, CuB5IIIC8VI, and Cu3B5IIIC9VI ordered defect compounds (ODCs) is studied. Analysis of UT in such a large number of ternary compounds with the adjustable parameters P and N permits us to have a better understanding of their physical importance. These parameters are used to explain the variation of Urbach’s energy EU with temperature T. They take into account the basic effect of substitutional disorder caused by molecularity and deviation from stoichiometry and also the handicap in the thermal weight due to the distribution of the resulting additional phonon modes, respectively. They play an important role in determining quantitatively the presence of structural defects. P explains quite well higher values of hνp observed in multinary compounds, and N indicates when an order–disorder phase transition could occur in these materials. It is also found that the energy of phonons involved in the formation of the photon absorption edge hνp in ODCs is higher than that observed in normal CuBIIIC2VI chalcopyrite compounds and increases linearly as the effective cation radius reff increases in the sequence CuB5IIIC8VI→CuB3IIIC5VI→Cu3B5IIIC9VI. The analysis also suggests that the magnitude of these parameters can be very useful in device applications of these materials such as solar cells and thermoelectric power generation.
Transition from intrinsic to extrinsic anomalous Hall effect in the ferromagnetic Weyl semimetal PrAlGe1−xSix
Authors: Yang Hung-Yu , Singh Bahadur , Lu Baozhu , Huang Cheng-Yi , Bahrami Faranak , Chiu Wei-Chi , Graf David , Huang Shin-Ming , Wang Baokai , Lin Hsin , Torchinsky Darius , Bansil Arun , Tafti Fazel
Published: January 2020

Recent reports of a large anomalous Hall effect (AHE) in ferromagnetic Weyl semimetals (FM WSMs) have led to a resurgence of interest in this enigmatic phenomenon. However, due to a lack of tunable materials, the interplay between the intrinsic mechanism caused by Berry curvature and extrinsic mechanisms due to scattering remains unclear in FM WSMs. In this contribution, we present a thorough investigation of both the extrinsic and intrinsic AHEs in a new family of FM WSMs, PrAlGe1−xSix, where x can be tuned continuously. Based on the first-principles calculations, we show that the two end members, PrAlGe and PrAlSi, have different Fermi surfaces, but similar Weyl node structures. Experimentally, we observe moderate changes in the anomalous Hall coefficient (RS), but significant changes in the ordinary Hall coefficient (R0) in PrAlGe1−xSix as a function of x. By comparing the magnitude of R0 and RS, we identify two regimes: |R0| < |RS| for x ≤ 0.5 and |R0| > |RS| for x > 0.5. Through a detailed scaling analysis, we uncover a universal anomalous Hall conductivity (AHC) from intrinsic contribution when x ≤ 0.5. Such a universal AHC is absent for x > 0.5. Our study, thus, reveals the significance of extrinsic mechanisms in FM WSMs and reports the first observation of the transition from the intrinsic to extrinsic AHE in PrAlGe1−xSix.
Pressure responses of halide perovskites with various compositions, dimensionalities, and morphologies
Authors: Li Mei , Liu Tianbiao , Wang Yonggang , Yang Wenge , Lü Xujie
Published: January 2020

Metal halide perovskites (HPVs) have been greatly developed over the last decade, with various compositions, dimensionalities, and morphologies, leading to an emergence of high-performance photovoltaic and optoelectronic applications. Despite the tremendous progress made, challenges remain, which calls for a better understanding of the fundamental mechanisms. Pressure, a thermodynamic variable, provides a powerful tool to tune materials’ structures and properties. In combination with in situ characterization methods, high-pressure research could provide a better fundamental understanding. In this review, we summarize the recent studies of the dramatic, pressure-induced changes that occur in HPVs, particularly the enhanced and emergent properties induced under high pressure and their structure-property relationships. We first introduce the characteristics of HPVs and the basic knowledge of high-pressure techniques, as well as in situ characterization methods. We then discuss the effects of pressure on HPVs with different compositions, dimensionalities, and morphologies, and underline their common features and anomalous behaviors. In the last section, we highlight the main challenges and provide suggestions for possible future research on high-pressure HPVs.
Measurement of electron affinity of iridium atom and photoelectron angular distributions of iridium anion
Authors: Lu Yuzhu , Zhao Jing , Tang Rulin , Fu Xiaoxi , Ning Chuangang
Published: January 2020

The latest electron affinity value of an iridium atom is 1.564 36(15) eV, determined via a method based on the Wigner threshold law by Bilodeau and co-workers. However, they observed a significant deviation from the Wigner threshold law in the threshold photodetachment experiment. To address this dilemma, we conducted high-resolution photoelectron spectroscopy of Ir− via the slow-electron velocity-map imaging method in combination with an ion trap. The electron affinity of Ir was measured to be 12 614.97(9) cm−1 or 1.564 057(11) eV. We find that the Wigner threshold law is still valid for the threshold photodetachment of Ir− through a p-wave fitting of the photodetachment channel Ir−5d86s23F4→Ir5d86sb4F9/2. The photoelectron angular distributions of photodetachment channels Ir−5d86s23F4→Ir5d76s2a4F9/2 and Ir−5d86s23F4→Ir5d86sb4F9/2 were also investigated. The behavior of anisotropy parameter β indicates a strong interaction between the two channels. Moreover, the energy level 3P2 of Ir−, which was not observed in the previous works, was experimentally determined to be 4163.24(16) cm−1 above the ground state.
System–bath entanglement theorem with Gaussian environments
Authors: Du Peng-Li , Wang Yao , Xu Rui-Xue , Zhang Hou-Dao , Yan YiJing
Published: January 2020

In this work, we establish a so-called “system–bath entanglement theorem,” for arbitrary systems coupled with Gaussian environments. This theorem connects the entangled system–bath response functions in the total composite space to those of local systems, as long as the interacting bath spectral densities are given. We validate the theorem with direct evaluation via the exact dissipaton-equation-of-motion approach. Therefore, this work enables various quantum dissipation theories, which originally describe only the reduced system dynamics, for their evaluations on the system–bath entanglement properties. Numerical demonstrations are carried out on the Fano interference spectroscopies of spin–boson systems.
Intrinsic piezoelectricity of monolayer group IV–V MX2: SiP2, SiAs2, GeP2, and GeAs2
Authors: Xu Yu , Li Zhenqing , He Chaoyu , Li Jin , Ouyang Tao , Zhang Chunxiao , Tang Chao , Zhong Jianxin
Published: January 2020

The intrinsic piezoelectric effect of the monolayer group IV–V MX2 (M = Si, Ge and X = P, As) is systematically investigated using the density functional theory based on first-principles calculations and the modern theory of polarization. We find that the piezoelectric coefficients d112D of the compounds are approximately one order of magnitude larger than those of other 2D materials, such as hexagonal boron nitride and MoS2, which have been widely studied both experimentally and theoretically. Furthermore, the coefficients d112D are always one order of magnitude larger than d122D, showing obvious anisotropy. Such strong anisotropy can be easily understood by the C2v symmetry and puckered configuration along the a direction, which leads to considerable flexibility. Our results show that these monolayers of group IV–V MX2 have potential for applications in nanosized sensors, piezotronics, and energy-harvesting in portable electronic nanodevices. Owing to the recent advances in synthesis technologies, it is expected that these monolayers may be put to a wide practical use in the future.
Particle separation induced by triangle obstacles in a straight channel
Authors: Wu Jian-Chun , Dong Tian-Wen , Jiang Gui-Wen , An Meng , Ai Bao-Quan
Published: January 2020

Efficient separation of particles has ever-growing importance in both fundamental research and nanotechnological applications. However, such particles usually suffer from some fluctuations from external surroundings and outside intervention from unknown directions. Here, we numerically investigate the transport of Brownian particles in a straight channel with regular arrays of equilateral triangle obstacles. The particles can be rectified by the triangle obstacles under the action of an oscillating (square wave) force. At the given amplitude and frequency of the oscillating force, the transport is sensitively dependent on the force direction and particle size. In the cases of longitudinal and transversal oscillating force, the particles with different sizes exhibit different transport behaviors. Interestingly, under a constant force in the longitudinal direction, the phenomenon of particle separation is observed, where the particles with different radii will move in different directions. Furthermore, we also study the transport of Brownian particles driven by a tilt oscillating force. By choosing proper force directions, we can observe the gating phenomenon and transport reversal. Under different driving conditions, we can separate particles of different sizes and make them move in opposite directions.
Improved reproductive growth of euhalophyte Suaeda salsa under salinity is correlated with altered phytohormone biosynthesis and signal transduction
Authors: Guo Jianrong , Lu Chaoxia , Zhao Fangcheng , Gao Shuai , Wang Baoshan
Published: January 2020

Phytohormones are essential for plant reproductive growth. Salinity limits crop reproductive growth and yield, but improves reproductive growth of euhalophytes. However, little is known about the mechanisms underlying salinity’s effects on plant reproductive growth. To elucidate the role of plant hormones in flower development of the euhalophyte Suaeda salsa under saline conditions, we analysed endogenous gibberellic acid (GA3,4), indoleacetic acid (IAA), zeatin riboside (ZR), abscisic acid (ABA), and brassinosteroids (BRs) during flowering in control (0 mM) and NaCl-treated (200 mM) plants. At the end of vegetative growth, endogenous GA3, GA4, ABA and BR contents in stems of NaCl-treated plants were significantly higher than those in controls. During flowering, GA3, GA4, IAA and ZR contents showed the most significant enhancement in flower organs of plants treated with NaCl when compared with controls. Additionally, genes related to ZR, IAA, GA, BR and ABA biosynthesis and plant hormone signal transduction, such as those encoding CYP735A, CYP85A, GID1, NCED, PIF4, AHP, TCH4, SnRK2 and ABF, were upregulated in S. salsa flowers from NaCl-treated plants. These results suggest that coordinated upregulation of genes involved in phytohormone biosynthesis and signal transduction contributes to the enhanced reproductive growth of S. salsa under salinity.
Nanoscopy through a plasmonic nanolens
Authors: Horton Matthew J. , Ojambati Oluwafemi S. , Chikkaraddy Rohit , Deacon William M. , Kongsuwan Nuttawut , Demetriadou Angela , Hess Ortwin , Baumberg Jeremy J.
Published: January 2020

Plasmonics now delivers sensors capable of detecting single molecules. The emission enhancements and nanometer-scale optical confinement achieved by these metallic nanostructures vastly increase spectroscopic sensitivity, enabling real-time tracking. However, the interaction of light with such nanostructures typically loses all information about the spatial location of molecules within a plasmonic hot spot. Here, we show that ultrathin plasmonic nanogaps support complete mode sets which strongly influence the far-field emission patterns of embedded emitters and allow the reconstruction of dipole positions with 1-nm precision. Emitters in different locations radiate spots, rings, and askew halo images, arising from interference of 2 radiating antenna modes differently coupling light out of the nanogap, highlighting the imaging potential of these plasmonic “crystal balls.” Emitters at the center are now found to live indefinitely, because they radiate so rapidly.
Opioid system is necessary but not sufficient for antidepressive actions of ketamine in rodents
Authors: Klein Matthew E. , Chandra Joshua , Sheriff Salma , Malinow Roberto
Published: January 2020

Significance

Ketamine, an NMDA receptor antagonist, has generated intense excitement as a therapy for treatment-resistant depression. However, ketamine and its metabolites can act on a wide range of targets, including opioid receptors, which has raised concerns. Using behavioral and cellular assays in rodents, we find that blocking opioid function prevents the antidepressant-like effects of ketamine. However, in contrast to ketamine, administration of a µ-opioid agonist is hedonic and ineffective on anhedonia/avolition. Furthermore, ketamine’s cellular actions are both mimicked and occluded by an NMDAR antagonist but not by a µ-opioid agonist. These results suggest that ketamine does not act as a μ-opioid agonist, but functional μ-opioid receptors are permissive for the antidepressant effects of ketamine.
Simulation-based optimization of inner layout of a theater considering the effect of pedestrians*
Authors: Gao Qing-Fei , Tao Yi-Zhou , Wei Yan-Fang , Wu Cheng , Dong Li-Yun
Published: January 2020

We propose an extended cellular automaton model based on the floor field. The floor field can be changed accordingly in the presence of pedestrians. Furthermore, the effects of pedestrians with different speeds are distinguished, i.e., still pedestrians result in more increment of the floor field than moving ones. The improved floor field reflects impact of pedestrians as movable obstacles on evacuation process. The presented model was calibrated by comparing with previous studies. It is shown that this model provides a better description of crowd evacuation both qualitatively and quantitatively. Then we investigated crowd evacuation from a middle-size theater. Four possible designs of aisles in the theater are studied and one of them is the actual design in reality. Numerical simulation shows that the actual design of the theater is reasonable. Then we optimize the position of the side exit in order to reduce the evacuation time. It is shown that the utilization of the two exits at bottom is less than that of the side exits. When the position of the side exit is shifted upwards by about 1.6 m, it is found that the evacuation time reaches its minimum.
Microstructure evolution and passivation quality of hydrogenated amorphous silicon oxide (a-SiOx:H) on 〈100〉- and 〈111〉-orientated c-Si wafers*
Authors: Chen Jun-Fan , Zhao Sheng-Sheng , Yan Ling-Ling , Ren Hui-Zhi , Han Can , Zhang De-Kun , Wei Chang-Chun , Wang Guang-Cai , Hou Guo-Fu , Zhao Ying , Zhang Xiao-Dan
Published: January 2020

Hydrogenated amorphous silicon oxide (a-SiO
x
:H) is an attractive passivation material to suppress epitaxial growth and reduce the parasitic absorption loss in silicon heterojunction (SHJ) solar cells. In this paper, a-SiO
x
:H layers on different orientated c-Si substrates are fabricated. An optimal effective lifetime (τ
eff) of 4743 μs and corresponding implied open-circuit voltage (i V
oc) of 724 mV are obtained on 〈100〉-orientated c-Si wafers. While τ
eff of 2429 μs and i V
oc of 699 mV are achieved on 〈111〉-orientated substrate. The FTIR and XPS results indicate that the a-SiO
x
:H network consists of SiO
x
(Si-rich), Si– OH, Si– O– SiH
x
, SiO2≡Si– Si, and O3 ≡S– Si. A passivation evolution mechanism is proposed to explain the different passivation results on different c-Si wafers. By modulating the a-SiO
x
:H layer, the planar silicon heterojunction solar cell can achieve an efficiency of 18.15%.
Comparison study of GaN films grown on porous and planar GaN templates*
Authors: Ding Shan , Li Yue-Wen , Xiu Xiang-Qian , Hua Xue-Mei , Xie Zi-Li , Tao Tao , Chen Peng , Liu Bin , Zhang Rong , Zheng You-Dou
Published: January 2020

The GaN thick films have been grown on porous GaN template and planar metal-organic chemical vapor deposition (MOCVD)-GaN template by halide vapor phase epitaxy (HVPE). The analysis results indicated that the GaN films grown on porous and planar GaN templates under the same growth conditions have similar structural, optical, and electrical properties. But the porous GaN templates could significantly reduce the stress in the HVPE-GaN epilayer and enhance the photoluminescence (PL) intensity. The voids in the porous template were critical for the strain relaxation in the GaN films and the increase of the PL intensity. Thus, the porous GaN converted from β-Ga2O3 film as a novel promising template is suitable for the growth of stress-free GaN films.
Comparative study on transport properties of N-, P-, and As-doped SiC nanowires: Calculated based on first principles*
Authors: Li Ya-Lin , Gong Pei , Fang Xiao-Yong
Published: January 2020

According to the one-dimensional quantum state distribution, carrier scattering, and fixed range hopping model, the structural stability and electron transport properties of N-, P-, and As-doped SiC nanowires (N-SiCNWs, P-SiCNWs, and As-SiCNWs) are simulated by using the first principles calculations. The results show that the lattice structure of N-SiCNWs is the most stable in the lattice structures of the above three kinds of doped SiCNWs. At room temperature, for unpassivated SiCNWs, the doping effect of P and As are better than that of N. After passivation, the conductivities of all doped SiCNWs increase by approximately two orders of magnitude. The N-SiCNW has the lowest conductivity. In addition, the N-, P-, As-doped SiCNWs before and after passivation have the same conductivity–temperature characteristics, that is, above room temperature, the conductivity values of the doped SiCNWs all increase with temperature increasing. These results contribute to the electronic application of nanodevices.
Tailoring electronic properties of two-dimensional antimonene with isoelectronic counterparts*
Authors: Zhang Ye , Guo Huai-Hong , Dong Bao-Juan , Zhu Zhen , Yang Teng , Wang Ji-Zhang , Zhang Zhi-Dong
Published: January 2020

Using ab initio density functional theory calculations, we explore the three most stable structural phases, namely, α, β, and cubic (c) phases, of two-dimensional (2D) antimonene, as well as its isoelectronic counterparts SnTe and InI. We find that the band gap increases monotonically from Sb to SnTe to InI along with an increase in ionicity, independent of the structural phases. The band gaps of this material family cover the entire visible-light energy spectrum, ranging from 0.26 eV to 3.37 eV, rendering them promising candidates for optoelectronic applications. Meanwhile, band-edge positions of these materials are explored and all three types of band alignments can be achieved through properly combining antimonene with its isoelectronic counterparts to form heterostructures. The richness in electronic properties for this isoelectronic material family sheds light on possibilities to tailor the fundamental band gap of antimonene via lateral alloying or forming vertical heterostructures.
Influence of dynamic tissue properties on temperature elevation and lesions during HIFU scanning therapy: Numerical simulation*
Authors: Zou Xiao , Dong Hu , Qian Sheng-You
Published: January 2020

When large tumors are treated, ablation of the entire volume of tumors requires multiple treatment spots formed by high intensity-focused ultrasound (HIFU) scanning therapy. The heating effect of HIFU on biological tissue is mainly reflected in temperature elevation and tissue lesions. Tissue property parameters vary with temperature and, in turn, the distribution of temperature as well as the heating effects change accordingly. In this study, an HIFU scanning therapy model considering dynamic tissue properties is provided. The acoustic fields and temperature fields are solved combining the Helmholtz wave equation with Pennes bio-heat transfer equation based on the finite element method (FEM) to investigate the effects of various tissue properties (i.e., the attenuation coefficient, acoustic velocity, thermal conductivity, specific heat capacity, density, and blood perfusion rate) on heating performance. Comparisons of the temperature distribution and thermal lesions under static and dynamic properties are made based on the data of tissue property parameters varying with temperature. The results show that the dynamic changes of thermal conductivity, specific heat capacity, and acoustic velocity may account for the decrease of temperature elevation in HIFU treatment, while the dynamic changes of attenuation coefficient, density, and blood perfusion rate aggravate the increase of temperature on treatment spots. Compared with other properties, the dynamic change of attenuation coefficient has a greater impact on tissue temperature elevation. During HIFU scanning therapy, the temperature elevation and tissue lesions of the first treatment spot are smaller than those of the subsequent treatment spots, but the temperature on the last treatment spot drops faster during the cooling period. The ellipsoidal tissue lesion is not symmetrical; specifically, the part facing toward the previous treatment spot tends to be larger. Under the condition of the same doses, the temperature elevation and the size of tissue lesions under dynamic properties present significant growth in comparison to static properties. Besides, the tissue lesion begins to form earlier with a more unsymmetrical shape and is connected to the tissue lesion around the previous treatment spot. As a result, lesions around all the treatment spots are connected with each other to form a closed lesion region. The findings in this study reveal the influence of dynamic tissue properties on temperature elevation and lesions during HIFU scanning therapy, providing useful support for the optimization of treatment programs to guarantee higher efficacy and safety.
Influence of Zr50Cu50 thin film metallic glass as buffer layer on the structural and optoelectrical properties of AZO films*
Authors: Zhang Bao-Qing , Liu Gao-Peng , Zong Hai-Tao , Fu Li-Ge , Wei Zhi-Fei , Yang Xiao-Wei , Cao Guo-Hua
Published: January 2020

Aluminum-doped ZnO (AZO) thin films with thin film metallic glass of Zr50Cu50 as buffer are prepared on glass substrates by the pulsed laser deposition. The influence of buffer thickness and substrate temperature on structural, optical, and electrical properties of AZO thin film are investigated. Increasing the thickness of buffer layer and substrate temperature can both promote the transformation of AZO from amorphous to crystalline structure, while they show (100) and (002) unique preferential orientations, respectively. After inserting Zr50Cu50 layer between the glass substrate and AZO film, the sheet resistance and visible transmittance decrease, but the infrared transmittance increases. With substrate temperature increasing from 25 °C to 520 °C, the sheet resistance of AZO(100 nm)/Zr50Cu50(4 nm) film first increases and then decreases, and the infrared transmittance is improved. The AZO(100 nm)/Zr50Cu50(4 nm) film deposited at a substrate temperature of 360 °C exhibits a low sheet resistance of 26.7 Ω/□, high transmittance of 82.1% in the visible light region, 81.6% in near-infrared region, and low surface roughness of 0.85 nm, which are useful properties for their potential applications in tandem solar cell and infrared technology.
Effects of electron correlation and the Breit interaction on one- and two-electron one-photon transitions in double K hole states of He-like ions (10 ≤ Z ≤ 47)*
Authors: Ding Xiaobin , Wu Cunqiang , Cao Mingxin , Zhang Denghong , Zhang Mingwu , Xue Yingli , Yu Deyang , Dong Chenzhong
Published: January 2020

The x-ray energies and transition rates associated with single and double electron radiative transitions from the double K hole state 2s2p to the 1s2s and 1s2 configurations of 11 selected He-like ions (10 ≤ Z ≤ 47) are calculated using the fully relativistic multi-configuration Dirac–Fock method (MCDF). An appropriate electron correlation model is constructed with the aid of the active space method, which allows the electron correlation effects to be studied efficiently. The contributions of the electron correlation and the Breit interaction to the transition properties are analyzed in detail. It is found that the two-electron one-photon (TEOP) transition is correlation sensitive. The Breit interaction and electron correlation both contribute significantly to the radiative transition properties of the double K hole state of the He-like ions. Good agreement between the present calculation and previous work is achieved. The calculated data will be helpful to future investigations on double K hole decay processes of He-like ions.
Evolution of the International System of Units: considering the challenge of user adoption
Authors: Brown Richard J C
Published: January 2020

This discussion considers the challenge of making amendments to the International System of Units (SI) in terms of the varying levels of adoption of these amendments by users of the SI. It categorises possible amendments along two scales. First, whether these are changes or additions to the SI; and second whether these amendments are optional or compulsory. Where amendments fall on these two scales gives an indication of whether they are low-risk or high-risk actions, in terms of their likely adoption by users of the SI and the confusion that lack of adoption might cause. Proposed amendments to the SI of current interest are considered with respect to this framework.
Preliminary study on the online reprocessing and refueling scheme for SD-TMS reactor
Authors: Ashraf O , Tikhomirov G V
Published: January 2020

The Single-fluid Double-zone Thorium Molten Salt reactor (SD-TMSR) has a promising future. Inherent safety, liquid fuel, and possibility of online reprocessing and refueling are unique potentials of the SD-TMSR. In the present study, the Monte Carlo code Serpent2 has been chosen to model the full core of the SD-TMSR. In addition, online reprocessing and refueling has been modeled based on subroutine provided by Serpent2. During the burnup time (10 years), the total mass of the fuel inside the core has been checked and found to be almost constant. Furthermore, we controlled the reactivity by adjusting the feed rate of fissile and/or fertile materials. The change of Keff, breeding ratio, Th and U-233 refill rates with burn-up time have been investigated. Additionally, the build-up of U-233 during 10 years has been calculated.
Evaluation of neutron activation of intermetallic matrices for dispersive nuclear fuel obtained by SH-synthesis
Authors: Balachov M.M. , Dolmatov O.Yu. , Kuznetsov M.S. , Kostyuchenko K.S. , Pimenov N.O. , Permikin A.A.
Published: January 2020

The paper describes a technique for obtaining intermetallic matrix materials based on Zr-Al and Ni-Al systems for dispersive nuclear fuel. This type of fuel is planned to be used in existing and future high-temperature nuclear reactors. Physical and mathematical modelling of the process of activation of matrices by neutron radiation showed that upon reaching the value of thermal neutron fluence of the order of 2.76⋅1021 n⋅cm−2, the activity of Zr-Al and Ni-Al matrices was 1.3 ⋅ 1010 and 0.2⋅1010 Bq/g, respectively. The analysis showed that in terms of exposure of irradiated fuel it is preferable to use a matrix based on the zirconium-aluminium system.
Application of pulsed heating in technologies of thermal-cycle processing of steel
Authors: Kozyr’ I.G. , Komolikov A.S.
Published: January 2020

In work features of application of concentrated streams of energy in technologies of thermal-cycle processing of metal products are considered. Examples of application of currents of high frequency at thermal-cycle processing are given. It is shown that application of concentrated streams of energy significantly reduces processing time, increases energy efficiency and allows receiving especially fine structure in the surface layers.
Determination of Effective Temperature at in-pile Study of Nuclear Fuel
Authors: Belendryasova E G , Panasenko R A , Tutnov I A , Anufriev B F , Maksimkin A I
Published: January 2020

In this work we describe the method to calculate the creep rate of uranium-gadolinium oxide fuel through the effective temperature of fuel samples. Effective temperature characterizes the creep rate with uneven temperature distribution during operation of fuel. Modern modeling technologies presented in ANSYS software were used to calculate the effective temperature. The calculations are compared with measures from in-pile experiments. The results of this work are extremely important for the licensing of new type of nuclear fuel.