bluuebunny/crossref_metadata_2025 huggingface dataset:
Aluminum oxides as alternative building blocks for efficient layer-by-layer blocking layers in dye-sensitized solar cells
Authors: Nascimento Lucas L , Brussasco Jessica G , Garcia Igor A , Paula Leonardo F , Polo A S , Patrocinio Antonio Otavio T
Published: October 2020

All inorganic layer-by-layer (LbL) thin films composed by TiO2 nanoparticles and [Al(OH)4]− anions (TiO

2

/AlO

x
) as well as Al2O3 and Nb2O5 nanoparticles (Al

2

O

3

/Nb

2

O

5
) have been deposited to fluorine-doped tin-oxide coated glass (FTO) surfaces and applied as blocking layers in dye-sensitized solar cells (DSCs). Structural and morphological characterization of the LbL films by different techniques reveal that in TiO

2

/AlO

x
assembly, aluminate anions undergo condensation reactions on the TiO2 surface leading to the formation of highly homogeneous films with unique optical properties. After 25 depositions transmittance losses below 10% in relation to the bare FTO substrate are observed. Electrochemical impedance spectroscopy shows that TiO

2

/AlO

x
layers impose an effective barrier for the charge recombination at FTO/electrolyte interface with an electron exchange time constant 50-fold higher than that for bare FTO. As a result, an improvement of 85% in the overall conversion efficiency of DSCs was observed with the employment of TiO2/AlOx blocking layers. Al

2

O

3

/Nb

2

O

5
LbL films can also work as blocking layers in DSCs but not as efficient, which is associated with the poor homogeneity of the film and its capacitive behavior. The production of cost-effective blocking layers with a low light scattering in the visible region is an important feature toward the application of DSC in other Building-integrated photovoltaic applications.
Instability induced by exchange forces in a 2D electron gas in a magnetic field with uniform gradient
Authors: Hoodbhoy Pervez
Published: October 2020

The exchange interaction is investigated theoretically for electrons confined to a 2D sample placed in a linearly varying magnetic field perpendicular to the plane. Unusual and interesting behavior is predicted: starting from zero electrons, as one adds electrons to the system the maximum distance an electron can travel transverse to the B

z
= 0 line (i.e. the system’s width) increases continuously but this width will subsequently begin shrinking at some critical number. However this collapse will be reversed as the number crosses another critical value, which we estimate here. For electron parameters typical for two dimensional electron gases, the instability could be observable at sufficiently low electron densities. A Hartree Fock equation is derived. We also show that in an appropriate asymptotic limit this leads to an approximately local potential. One key lesson is that the exchange interaction is large and cannot be reasonably excluded from any valid theoretical investigation.
Helping to know if you are properly protected while working in interventional cardiology
Authors: Vano E , RM Sanchez Casanueva , JM Fernandez Soto
Published: October 2020

Occupational protection is still a challenge for interventional cardiology. One of the main problems is the occasional improper use of the ceiling suspended screen. We present a methodology to audit the correct use of the shielding using active electronic dosimeters. To improve the protection, we suggest the use of an alert based on the ratio between the occupational dose per procedure, measured by a personal electronic dosimeter over the lead apron, and the dose measured by an unshielded dosimeter, located at the C-arm. The new electronic dosimeters and the automatic dose management systems allow processing the dosimetric data for individual procedures and for the radiation events, sending the values (wireless) to a central database. We selected six interventional cardiologists and analysed 385 interventional procedures involving about 30 000 radiation events. Our results suggest that for individual procedures, standard values of the ratio between operator dose and the C-arm reference dose, should be between 1%–2% for a proper use of the shielding. Percentage values ≥5%–10% for individual procedures, require an analysis of the different radiation events to identify the lack of occupational protection and suggest corrective actions. In our sample, half of the operators should improve the use of the shielding in around 20% of the procedures. Using this ratio as an alert to operators allows optimising occupational radiation protection and discriminating between high occupational doses derived from complex procedures and high doses due to the improper use of the protective screen.
Characterisation of the combustion behaviours of individual pulverised coal particles entrained by air using image processing techniques
Authors: Qian Xiangchen , Li Fengjie , Yan Yong , Lu Gang , Liu Hao
Published: October 2020

The combustion characteristics of individual coal particles are the basis for a deep understanding of the macroscopic pulverised coal combustion in power plant boilers. This work proposes a quantitative method to characterise the combustion behaviours of individual pulverised coal particles by measuring a set of physical parameters from digital images of the particles. The combustion process of pulverised particles of bituminous coal in a visual drop tube furnace was recorded by a high-speed camera with a frame rate of 6200 frames per second. An improved-Canny algorithm was developed to extract the combustion zones of a coal particle in both the volatile and char combustion phases. Using the improved-Canny and Otsu algorithms, the unburned part of the particle was identified in the volatile combustion phase. Characteristic parameters of coal particles, including the area, brightness, length, width and aspect ratio of volatile flame, and falling velocity, were derived from the processed images. The results obtained show that the volatile and char combustion took place successively and the volatile matter was combusted almost as soon as it was released. The particle travelled upward for around 14 ms during the early stage of combustion due to the influence of devolatilisation and volatile combustion. The particle also exhibited a slight difference in the rotation frequency at different combustion phases.
Modeling evolution of composition patterns in a binary surface alloy
Authors: Khenner Mikhail , Henner Victor
Published: October 2020

Evolution of composition patterns in the annealed, single-crystal surface alloy film is considered in the presence of the spinodal decomposition, the compositional stress and the diffusion anisotropy. While the former two effects contribute to overall phase separation, the anisotropy, correlated with the surface crystallographic orientation, guides the in-plane formation and orientation of a pattern. The impacts of the anisotropy parameters on patterns are systematically computed for [110], [100], and [111]-oriented fcc cubic alloy surfaces.
Rigorous justification of the hydrostatic approximation for the primitive equations by scaled Navier–Stokes equations*
Authors: Furukawa Ken , Giga Yoshikazu , Hieber Matthias , Hussein Amru , Kashiwabara Takahito , Wrona Marc
Published: October 2020

Considering the anisotropic Navier–Stokes equations as well as the primitive equations, it is shown that the horizontal velocity of the solution to the anisotropic Navier–Stokes equations in a cylindrical domain of height ɛ with initial data

u

0

=

(

v

0

,

w

0

)

∈

B

q
,
p

2
−
2
/
p

, 1/q + 1/p ⩽ 1 if q ⩾ 2 and 4/3q + 2/3p ⩽ 1 if q ⩽ 2, converges as ɛ → 0 with convergence rate

O

(

ε

)

to the horizontal velocity of the solution to the primitive equations with initial data v
0 with respect to the maximal-L

p
–L

q
-regularity norm. Since the difference of the corresponding vertical velocities remains bounded with respect to that norm, the convergence result yields a rigorous justification of the hydrostatic approximation in the primitive equations in this setting. It generalizes in particular a result by Li and Titi for the L
2–L
2-setting. The approach presented here does not rely on second order energy estimates but on maximal L

p
–L

q
-estimates which allow us to conclude that local in-time convergence already implies global in-time convergence, where moreover the convergence rate is independent of p and q.
Typical properties of interval maps preserving the Lebesgue measure
*
Authors: Bobok Jozef , Troubetzkoy Serge
Published: October 2020

We consider the class of the continuous functions from [0, 1] into itself which preserve the Lebesgue measure. This class endowed with the uniform metric constitutes a complete metric space. We investigate the dynamical properties of typical maps from the space.
Limit theorems for some time-dependent expanding dynamical systems
Authors: Hafouta Yeor
Published: October 2020

In this paper we will prove various probabilistic limit theorems for some classes of distance expanding sequential dynamical systems (SDS). Our starting point here is certain sequential complex Ruelle–Perron–Frobenius (RPF) theorems which were (essentially) proved by Hafouta and Kifer (2018 Nonconventional Limit Theorems and Random Dynamics) and Hafouta (2019 arXiv:1910.12792) using contraction properties of a complex version of the projective Hilbert metric developed by Rugh (2010 Ann. Math.
171 1707–52). We will start from the growth rate of the variances of the underlying partial sums. This is well understood in the random dynamics setup, when the maps are stationary, but not in the SDS setup, where various growth rates can occur. Some of our results in this direction rely on certain type of stability in these RPF theorems, which is one of the novelties of this paper. Then we will provide general conditions for several classical limit theorems to hold true in the sequential setup. Some of our general results mostly have applications for composition of random non-stationary maps, while the conditions of the other results hold true for general type of SDS. In the latter setup, results such as the Berry–Esseén theorem and the local central limit theorem were not obtained so far even for independent but not identically distributed maps, which is a particular case of the setup considered in this paper.
Energy spread estimation of radioactive oxygen ion beams using optical imaging
Authors: Kang Han Gyu , Yamamoto Seiichi , Takyu Sodai , Nishikido Fumihiko , Mohammadi Akram , Akamatsua Go , Sato Shinji , Yamaya Taiga
Published: October 2020

Radioactive ion (RI) beams combined with in-beam positron emission tomography enable accurate in situ beam range verification in heavy ion therapy. However, the energy spread of the radioactive beams generated as secondary beams is wider than that of conventional stable heavy ion beams which causes Bragg peak region and distal falloff region broadening. Therefore, the energy spread of the RI beams should be measured carefully for their quality control. Here, we proposed an optical imaging technique for the energy spread estimation of radioactive oxygen ion beams. A polymethyl methacrylate phantom (10.0 × 10.0 × 9.9 cm3) was irradiated with an 15O beam (mean energy = 247.7 MeV u−1, standard deviation = 6.8 MeV u−1) in the Heavy Ion Medical Accelerator in Chiba. Three different momentum acceptances of 1%, 2% and 4% were used to get energy spreads of 1.9 MeV u−1, 3.4 MeV u−1 and 5.5 MeV u−1, respectively. The in-beam luminescence light and offline beam Cerenkov light images were acquired with an optical system consisting of a lens and a cooled charge-coupled device camera. To estimate the energy spread of the 15O ion beams, we proposed three optical parameters: (1) distal-50% falloff length of the prompt luminescence signals; (2) full-width at half maximum of the Cerenkov light signals in the beam direction; and (3) positional difference between the peaks of the Cerenkov light and the luminescence signals. These parameters estimated the energy spread with the respective mean squared errors of 2.52 × 10−3 MeV u−1, 5.91 × 10−3 MeV u−1, and 0.182 MeV u−1. The distal-50% falloff length of the luminescence signals provided the lowest mean squared error among the optical parameters. From the findings, we concluded optical imaging using luminescence and Cerenkov light signals offers an accurate energy spread estimation of 15O ion beams. In the future, the proposed optical parameters will be used for energy spread estimation of other RI beams as well as stable ion beams.
Cone beam CT multisource configurations: evaluating image quality, scatter, and dose using phantom imaging and Monte Carlo simulations
Authors: Becker Amy E , Hernandez Andrew M , Schwoebel Paul R , Boone John M
Published: October 2020

The purpose of this study was to compare various multisource configurations applied to cone beam CT (CBCT) using phantom imaging and Monte Carlo simulations. Image quality, scatter, and dose were evaluated in both overlapping (large cone angle) and collimated (small cone angle) configurations for CBCT. Four x-ray tube configurations were considered: traditional one source, three source overlapping, six source overlapping, and six source collimated. Image quality was evaluated on a prototype breast CT system using the following five phantoms: a Defrise phantom, a previously reported CBCT QA phantom (Corgi), a polyethylene cylinder, and two anthropomorphic phantoms (hand and knee). Scatter contamination and radiation dose were evaluated using Monte Carlo simulations of a voxelized polyethylene cylinder. The modulation of the Defrise phantom disks on average was 2.7X greater for the six source collimated configuration than the six source overlapping configuration. The data lost from cone beam artifact (spatial domain) and the null cone (frequency domain) in the overlapping configuration were completely recovered using the collimated configuration. The maximum scatter-to-primary ratio (SPR) for the overlapping configuration was 0.81 and the maximum SPR for the collimated configuration was 0.26. The average dose and maximum dose was 4X less in the collimated six source configuration when compared with the overlapping configurations. The maximum dose for the overlapping configurations (one, three & six) remained constant, but the average dose for the multisource (three & six source) overlapping configurations increased 25% when compared to the one source configuration. Use of a collimated multisource x-ray tube configuration was shown to provide significant improvements in image quality throughout the cone-beam geometry field-of-view, reduction in scatter contamination, and more efficient use of dose in comparison to both the traditional CBCT geometry with a single source and the overlapping multisource configurations.
In vivo neutron activation assembly design for quantification of trace elements using MCNP
Authors: Tabbassum Sana , Nie Linda H
Published: October 2020

Background: Trace and essential elements both play a crucial role in maintaining normal cellular and organ functions in human, while abnormal exposure to some of them is also potentially related to diseases, e.g. manganism. To study the association between elemental intake and health outcomes, accurate assessment of elemental uptake and storage in the human body is essential. Objective: Technology based on neutron activation analysis can be used for in vivo measurement of the trace elements given that the measurement system guarantees a low detection limit with an acceptable dose. This study aims to design and optimize a customized and portable deuterium–deuterium neutron generator-based irradiation assembly for the NAA of trace elements in vivo, using Monte Carlo simulations. Approach: The irradiation assembly includes a moderator, a fast neutron filter, a reflector, and shielding. The human hand phantoms doped with manganese (Mn) and potassium (K) are used to determine the respective elements’ system sensitivity and detection limit. Main results: The calculated detection limit is 0.16 μg Mn per gram dry bone (ppm) for Mn and 17 ppm for K, with an equivalent dose of 36 mSv to the hand for 10 min irradiation. Significance: This more sensitive in vivo neutron activation analysis system will detect trace elements in vivo.
Design and verification of novel silicon-controlled-rectifier-memristor based on standard CMOS process
Authors: Wang Yang , Cao Shengguo , Jin Xiangliang , Peng Yan , Luo Jun
Published: October 2020

Due to the unique nonlinear theory of memristors, it has been a research hotspot in the application of bionic synapses and neuromorphic computing for a long time. However, the currently designed memristors are difficult to be compatible with standard microelectronic processes to achieve large-scale integration. In this paper, a prototype structure of a silicon-controlled-rectifier-memristor (SCRM) will be proposed to solve the above problems. Technology computer aided design is utilized to simulate the memristive behavior of SCRM. The device is manufactured by the 0.18 μm bipolar complementary-metal-oxide-semiconductor double-diffused-metal-oxide-semiconductor process. The test platform was established to verify the memristive characteristics of SCRM. When a preset pulse is applied to both terminals of the device, the voltage and current of the SCRM are clamped to a lower level due to the negative-resistance effect, and hysteresis occurs. The I–V hysteresis loop fitted by extracting parameters verifies the consistency of theory, simulation and experiment. SCRM can change continuously between low-resistance state and high-resistance state. The design idea of SCRM compatible with silicon-based processes will promote further research on large-scale on-chip integrated neuromorphic computing.
Effect of steam conversion on the cellular structure, Young’s modulus and negative Poisson’s ratio of closed-cell foam
Authors: Duncan Olly , Allen Tom , Birch Alana , Foster Leon , Hart John , Alderson Andrew
Published: October 2020

Open-cell auxetic foams have shown potential for use in sporting and other protective equipment. Previous conversion methods for auxetic closed-cell foam used a bespoke pressure vessel. This work expands upon a recent method, using steam absorption followed by cooling and condensation, to change the cell shape of closed-cell foam to impart a negative Poisson’s ratio. Aiming to present a simple, repeatable conversion method, foam samples (20 × 10 × 100 mm) floating in water-filled (∼20 °C), covered ceramic containers (300 × 200 × 100 mm) were heated in an oven at 105 °C for between 1 and 6.5 hrs. Based on the results for these smaller samples, a larger sample of foam (30 × 100 × 100 mm) was also converted, with a steaming time of 8 hrs. The final volume ratio (original/final volume) increased with heating time, up to a maximum of 4.6. The amount and angle of re-entrant (inward-folding) cell walls increased with the final volume ratio as cells contracted further, as evidenced by micro-computed tomography. Poisson’s ratios, measured using digital image correlation, were as low as −0.3 in tension and −1.1 in compression. The tensile Young’s modulus increased from ∼2 up to ∼6 MPa with the final volume ratio and the compressive Young’s modulus reduced from ∼1.5 MPa for low values of the final volume ratio between one and three and then remained close to 1.5 MPa.
Multi-party quantum fingerprinting with weak coherent pulses: circuit design and protocol analysis
Authors: Gómez-Sousa Hipólito
Published: October 2020

Quantum communication has been leading the way of many remarkable theoretical results and experimental tests in physics. In this context, quantum communication complexity (QCC) has recently drawn earnest research attention as a tool to optimize the amounts of transmitted qubits and energy that are required to implement distributed computational tasks. On this matter, we introduce a novel multi-user quantum fingerprinting (QF) protocol that is ready to be implemented with existing technology. Particularly, we extend to the multi-user framework a well-known two-user coherent-state fingerprinting scheme. This generalization is highly non-trivial for a twofold reason, as it requires not only to extend the set of protocol rules but also to specify a procedure for designing the optical devices intended for the generalized protocol. Much of the importance of our work arises from the fact that the obtained QCC figures of merit allow direct comparison with the best-known classical multi-user fingerprinting protocol, of significance in the field of computer technologies and networking. Furthermore, as one of the main contributions of the manuscript, we deduce innovative analytical upper bounds on the amount of transmitted quantum information that are even valid in the two-user protocol as a particular case. These original analytical bounds are of interest for estimating the realistic protocol performance prior to experimental realizations. Ultimately, comparative results are provided to contrast different protocol implementation strategies and, importantly, to show that, under realistic circumstances, the multi-user protocol can achieve tasks that are impossible by using classical communication alone. Our work provides relevant contributions towards understanding the nature and the limitations of QF and, on a broader scope, also the limitations and possibilities of quantum-communication networks embracing a node that is accessed by multiple users at the same time.
Manipulation of valley splitting for the WSe2/NiCl2 heterostructure by adjusting the interlayer spacing and constructing a NiCl2/WSe2/NiCl2 heterojunction
Authors: Teng Sukai , Mao Xiujuan , Liu Ze , Liu Yang , Xu Xiuting , Li Linyang , Xie Xinjian , Fan Shanshan , Zhou Guoxiang , Li Jun , Li Jia
Published: October 2020

The electronic band structure and valley splitting of the WSe2/NiCl2 heterostructure have been investigated by density functional theory and Berry curvature calculations. We demonstrate that the valley polarization of monolayer WSe2 is induced due to the magnetic proximity effect caused by the single layer of ferromagnetic NiCl2. The magnitude of valley splitting depends on the stacking configurations of WSe2/NiCl2, and the maximum value of valley splitting reaches −11.87 meV. Large valley splitting can be achieved by adjusting the layer spacing and constructing a NiCl2/WSe2/NiCl2 heterojunction with Ni spins arranged in parallel between two NiCl2 sheets. The valley-contrasting Berry curvature between the K and K′ valleys suggests that the WSe2/NiCl2-based heterostructure could potentially be used as a valleytronic device to realize the valley-polarized anomalous Hall effect as both spin and valley filter.
The secondary ionization wave and characteristic map of surface discharge plasma in a wide time scale
Authors: Zhu Yifei , Wu Yun
Published: October 2020

The surface discharge is the elementary process in a broad range of low temperature plasma applications. Variation of voltage profiles with different time scales leads to the redistribution of deposited energy as well as electro-hydrodynamic forces of surface discharges, while the mechanism and scaling law is still unknown. On the basis of theoretical and numerical analysis, we show that a secondary surface ionization wave forms during the voltage rising slope when electron density decreases to a critical level while the voltage is still rising. A characteristic map of energy and electro-hydrodynamics force in time scales between 1 ns and 0.1 s at atmospheric pressure is proposed, opening the door towards the target-directed design of surface discharges.
Analysis and implementation of new fractional-order multi-scroll hidden attractors*
Authors: Cui Li , Luo Wen-Hui , Ou Qing-Li
Published: October 2020

To improve the complexity of chaotic signals, in this paper we first put forward a new three-dimensional quadratic fractional-order multi-scroll hidden chaotic system, then we use the Adomian decomposition algorithm to solve the proposed fractional-order chaotic system and obtain the chaotic phase diagrams of different orders, as well as the Lyaponov exponent spectrum, bifurcation diagram, and SE complexity of the 0.99-order system. In the process of analyzing the system, we find that the system possesses the dynamic behaviors of hidden attractors and hidden bifurcations. Next, we also propose a method of using the Lyapunov exponents to describe the basins of attraction of the chaotic system in the matlab environment for the first time, and obtain the basins of attraction under different order conditions. Finally, we construct an analog circuit system of the fractional-order chaotic system by using an equivalent circuit module of the fractional-order integral operators, thus realizing the 0.9-order multi-scroll hidden chaotic attractors.
Spin correlations in the S = 1 armchair chain Ni2NbBO6 as seen from NMR*
Authors: Zeng Kai-Yue , Ma Long , Xu Long-Meng , Tian Zhao-Ming , Ling Lang-Sheng , Pi Li
Published: October 2020

We report our nuclear magnetic resonance (NMR) study on the structurally spin chain compound Ni2NbBO6 with complex magnetic coupling. The antiferromagnetic transition is monitored by the line splitting resulting from the staggered internal hyperfine field. The magnetic coupling configuration proposed by the first-principle density functional theory (DFT) is supported by NMR spectral analysis. For the spin dynamics, a prominent peak at T ∼ 35 K well above the N éel temperature (T
N ∼ 20 K at μ
0
H = 10 T) is observed from the spin-lattice relaxation data. As compared with the dc-susceptibility, this behavior indicates an antiferromagnetic coupling with the typical energy scale of ∼3 meV. Thus, the Ni2NbBO6 compound can be viewed as strongly ferromagnetically coupled armchair spin chains along the crystalline b-axis. These facts place strong constraints on the theoretical model for this compound.
Compact NbN resonators with high kinetic inductance*
Authors: Wei Xing-Yu , Pan Jia-Zheng , Lu Ya-Peng , Jiang Jun-Liang , Li Zi-Shuo , Lu Sheng , Tu Xue-Cou , Zhao Qing-Yuan , Jia Xiao-Qing , Kang Lin , Chen Jian , Cao Chun-Hai , Wang Hua-Bing , Xu Wei-Wei , Sun Guo-Zhu , Wu Pei-Heng
Published: October 2020

We design and fabricate λ/2 coplanar waveguide NbN resonators, the thickness and length of which are only several nanometers and hundred microns, respectively. The quality factor of such compact resonators can reach up to 7.5 × 104 at single photon power level at 30 mK with the resonance frequency around 6.835 GHz. In order to tune the resonant frequency, the resonator is terminated to the ground with a dc-SQUID. By tuning the magnetic flux in the dc-SQUID, the effective inductance of the dc-SQUID is varied, which leads to the change in the resonant frequency of the resonator. The tunability range is more than 30 MHz and the quality factor is about 3 × 103. These compact and tunable NbN resonators have potential applications in the quantum information processing, such as in the precision measurement, coupling and/or reading out the quantum states of qubits.
Controllable microwave frequency comb generation in a tunable superconducting coplanar-waveguide resonator*
Authors: Wang Shuai-Peng , Chen Zhen , Li Tiefu
Published: October 2020

Frequency combs are useful in a wide range of applications, such as optical metrology and high-precision spectroscopy. We experimentally study a controllable frequency comb generated in a tunable superconducting coplanar-waveguide resonator in the microwave regime. A two-tone drive is applied on one of the resonance modes of the resonator and comb generation is observed around the resonance frequency of the resonator. Both central frequency and teeth density of the comb are precisely controllable, and the teeth spacing can be adjusted from Hz to MHz. Moreover, we show that a few hundreds of sidebands can be generated using a sufficiently strong drive power and the weakest drive power needed to generate the comb can be reduced to approach the quantum limit. These experimental results can be qualitatively explained via theoretical analysis.
The landscape and flux of a minimum network motif, Wu Xing*
Authors: Zhang Kun , Xia Ashley , Wang Jin
Published: October 2020

Wu-Xing theory is an ancient philosophy that serves as a guiding principle in the traditional Chinese medicine (TCM). It has been used to explain the unbalance among the TCM organ systems in disease states and provide treatment philosophy qualitatively. Until now, it is still a challenge to explore the Wu-Xing theory beyond its philosophical nature. In this study, we established a quantitative framework using the landscape and flux theory to characterize the nature of the Wu-Xing theory from a perspective of a minimal network motif and leave certain specific functional aspects of Wu-Xing theory for future exploration. We uncovered the irregular ring shape of projection landscape for the Wu-Xing network with several local basins and barriers. We found that the dynamics of the self-organized Wu-Xing system was determined by the underlying negative landscape gradient force and the nonequilibrium rotational flux. While the shape of the Wu-Xing landscape determines the stabilities of the states, the rotational flux guarantees the persistent periodic oscillation and the stability of the flow. This provides a physical and quantitative basis for Yin–Yang duality of the driving forces for determining the dynamics and behaviors of the living systems. Applying landscape and flux analysis, we can identify the key parameter for the dynamics/function of Wu-Xing network. These findings allow us to have a deeper understanding of the scientific merits of the ancient Wu-Xing theory from the network motif perspective.
Ground state cooling of an optomechanical resonator with double quantum interference processes*
Authors: Zhang Shuo , Li Tan , Duan Qian-Hen , Zhang Jian-Qi , Bao Wan-Su
Published: October 2020

We present a cooling scheme with a tripod configuration atomic ensemble trapped in an optomechanical cavity. With the employment of two different quantum interference processes, our scheme illustrates that it is possible to cool a resonator to its ground state in the strong cavity–atom coupling regime. Moreover, with the assistance of one additional energy level, our scheme takes a larger cooling rate to realize the ground state cooling. In addition, this scheme is a feasible candidate for experimental applications.
Grain boundary effect on structural, optical, and electrical properties of sol–gel synthesized Fe-doped SnO2 nanoparticles
Authors: V Archana , Mohan Lakshmi , P Kathirvel , S Saravanakumar
Published: October 2020

Tin oxide (SnO2) and iron-doped tin oxide (Sn1 – x
Fe
x
O2, x = 0.05 wt%, 0.10 wt%) nanoparticles are synthesized by the simple sol–gel method. The structural characterization using x-ray diffraction (XRD) confirms tetragonal rutile phases of the nanoparticles. The variations in lattice parameters and relative intensity with Fe-doping concentration validate the incorporation of iron into the lattice. The compressive strain present in the lattice estimated by using peak profile analysis through using Williamson–Hall plot also exhibits the influence of grain boundary formation in the lattice. The radiative recombination and quenching observed in optical characterization by using photoluminescence spectrum (PL) and the shift in the band gap estimated from UV-visible diffused reflectance spectrum corroborate the grain boundary influence. Raman spectrum and the morphological analysis by using a field emission scanning electron microscope (FESEM) also indicate the formation of grain boundaries. The compositional analysis by using energy dispersive x-ray spectrum (EDAX) confirms Fe in the SnO2 lattice. The conductivity studies exhibit that the impendence increases with doping concentration increasing and the loss factor decreases at high frequencies with doping concentration increasing, which makes the Sn1 – x
Fe
x
O2 a potential candidate for device applications.
Dissipative dynamics of an entangled three-qubit system via non-Hermitian Hamiltonian: Its correspondence with Markovian and non-Markovian regimes
Authors: Rastegarzadeh M , Tavassoly M K
Published: October 2020

We investigate an entangled three-qubit system in which only one of the qubits experiences the decoherence effect by considering a non-Hermitian Hamiltonian, while the other two qubits are isolated, i.e., do not interact with environment, directly. Then, the time evolution of the density matrix (for the pure as well as mixed initial density matrix) and the corresponding reduced density matrices are obtained, by which we are able to utilize the dissipative non-Hermitian Hamiltonian model with Markovian and non-Markovian regimes via adjusting the strange of the non-Hermitian term of the total Hamiltonian of the under-considered system.
Some theory and applications of 2N-dimensional canonical systems: periodic and nonperiodic
Authors: Acharya Keshav Raj , Ludu Andrei
Published: October 2020

In this paper, we study the 2N-dimensional canonical systems and their physical applications. We first discuss some basic theory including proving the existence of solutions of any canonical system and establish some properties of its fundamental solution. Then we discuss the periodic canonical systems, establish Floquet theory, and observe the asymptotic behavior of their solutions. We also explore some important physical applications of the systems, namely linear stability of periodic Hamiltonian systems, position-dependent effective mass, and pseudo-periodic nonlinear water waves.
Millimeter-wave generation using hybrid silicon photonics
Authors: Degli-Eredi Iterio , An Pengli , Drasbæk Jacob , Mohammadhosseini Hakimeh , Nielsen Lars , Tønning Peter , Rommel Simon , Monroy Idelfonso Tafur , Heck Martijn J R
Published: October 2020

Technological innovation with millimeter waves (mm waves), signals having carrier frequencies between 30 and 300 GHz, has become an increasingly important research field. While it is challenging to generate and distribute these high frequency signals using all-electronic means, photonic techniques that transfer the signals to the optical domain for processing can alleviate several of the issues that plague electronic components. By realizing optical signal processing in a photonic integrated circuit (PIC), one can considerably improve the performance, footprint, cost, weight, and energy efficiency of photonics-based mm-wave technologies. In this article, we detail the applications that rely on mm-wave generation and review the requirements for photonics-based technologies to achieve this functionality. We give an overview of the different PIC platforms, with a particular focus on hybrid silicon photonics, and detail how the performance of two key components in the generation of mm waves, photodetectors and modulators, can be optimized in these platforms. Finally, we discuss the potential of hybrid silicon photonics for extending mm-wave generation towards the THz domain and provide an outlook on whether these mm-wave applications will be a new milestone in the evolution of hybrid silicon photonics.
X-ray multi-modal intrinsic-speckle-tracking
Authors: Pavlov Konstantin M , Paganin David M , (Thomas) Li Heyang , Berujon Sebastien , Rougé-Labriet Hélène , Brun Emmanuel
Published: October 2020

We develop x-ray multi-modal intrinsic-speckle-tracking (MIST), a form of x-ray speckle-tracking that is able to recover both the position-dependent phase shift and the position-dependent small-angle x-ray scattering (SAXS) signal of a phase object. MIST is based on combining a Fokker–Planck description of paraxial x-ray optics, with an optical-flow formalism for x-ray speckle-tracking. Only two images need to be taken in the presence of the sample, corresponding to two different transverse positions of the speckle-generating membrane, in order to recover both the refractive and local-SAXS properties of the sample. Like the optical-flow x-ray phase-retrieval method which it generalises, the MIST method implicitly rather than explicitly tracks both the transverse motion and the diffusion of speckles that is induced by the presence of a sample. Application to x-ray synchrotron data shows the method to be efficient, rapid and stable.
Automated extended depth of focus digital holographic microscopy using electrically tunable lens
Authors: Barak Neelam , Kumari Vineeta , Sheoran Gyanendra
Published: October 2020

A combination of electrically tunable lens with a microscope objective lens (MO) for multifocal plane imaging capability is proposed. The method aims at extending the depth of focus of the MO by changing its axial range and field of view. The combination is implemented in a common path off-axis digital holographic microscopy configuration experimentally and it achieves an axial scanning range of 363.5 μm. It utilizes image plane holography to obtain in-focus images throughout the axial range. The proposed method demonstrates its application in quantitative phase imaging of the USAF 1951 test chart and flowing red blood cells at different axial depths. An axial depth variation of 0.76 μm–0.81 μm is obtained between two consecutive focused planes. The results validate and postulate the advantage of the proposed method over traditional extended depth-of-focus algorithms. The quantitative and qualitative results exploit the possibility of using the proposed method further for localization and tracking of flowing microscopic samples.
Non-invasive tracking of polarization rotation from speckle contrast using uncorrelated speckle patterns
Authors: Roy Abhijit , Singh Rakesh Kumar , Brundavanam Maruthi M
Published: October 2020

A technique based on the superposition of two uncorrelated speckle patterns and speckle contrast measurement is proposed and demonstrated to track the polarization rotation of an optical beam behind a scattering layer. One of the superposed speckle patterns is considered as reference, and it is shown that with the help of the reference speckle pattern of a known linear polarization, it is possible to track the polarization rotation behind a scattering layer in a non-invasive manner by measuring the contrast of the resultant speckle pattern. The working principle and the experimental demonstration of the proposed technique are presented, and the experimental results are compared with the theoretically predicted values. The performance of the proposed technique is quantitatively evaluated by determining the rotation of the polarization vector behind the scattering layer for two different cases, namely, polarization rotation by a half-wave plate and sugar solution of different concentrations, and good matches are found between the experimental results and the theoretical prediction. Issues like resolution of tracking the polarization vector rotation and determination of sugar solution concentration are also discussed in the context of the experimental results. The proposed technique can have potential applications in non-invasive sensing and biomedical studies.
Biaxial strain engineering of CVD and exfoliated single- and bi-layer MoS2 crystals
Authors: Michail Antonios , Anestopoulos Dimitris , Delikoukos Nikos , Parthenios John , Grammatikopoulos Spyridon , Tsirkas Sotirios A , Lathiotakis Nektarios N , Frank Otakar , Filintoglou Kyriakos , Papagelis Konstantinos
Published: October 2020

Single- and bi-layer MoS2 are two-dimensional semiconductors able to withstand very large deformations before failure, standing out as suitable templates for strain engineering applications and flexible electronics. It is imperative, for the proper integration of this material in practical applications, that the relationship between material property and strain is well understood. Two dimensional MoS2 crystals fabricated by chemical vapor deposition or micromechanical exfoliation are transferred onto flexible substrates and subjected to biaxial tension on a carefully designed and assessed loading stage with high accuracy and control. The successful stress transfer from substrate to the overlying 2D crystal is identified by in-situ monitoring of the strain-induced phonon frequency and photoluminescence peak shifts. Reliable values for the mode Grüneisen parameters and exciton deformation potentials were obtained by studying a significant number of crystals. The experimental results are backed by density functional theory calculations and are in good agreement with the experiments. This work highlights the potential of these materials in strain engineering applications and gives accurate values for single- and bi-layer MoS2 thermomechanical parameters.
Surface residual stress, micro-hardness and geometry of TC6 titanium alloy thin-wall parts processed by multiple oblique laser shock peening
Authors: Zhu Ran , Zhang Yongkang , Zhang Chi
Published: October 2020

The titanium alloy thin-walled part with light in weight and high specific strength is widely used in the aviation engine fan, turbine and compressor. The fatigue damage of the thin-walled part often happens under the action of the cyclic loads and high temperatures. Laser shock peening(LSP) is an innovative surface treatment process, which has been used to improve the fatigue life of metallic materials. Considering the shape and size of the thin-walled parts, the TC6 titanium alloy thin-wall parts were treated by the oblique incident laser beam in this work. The purpose of this study is to investigate the effects of multiple oblique LSP on TC6 titanium alloy thin-wall parts. Nd: YLF laser with a wavelength of 1053 nm was applied. The laser incidence angle was determined first by experiment. The effects of laser energies, impact times, pulse durations and pulse frequencies on the surface residual stress, micro-hardness and geometry of TC6 titanium alloy thin-wall parts were investigated. The results showed that by the use of oblique LSP, the higher surface residual stress and surface micro-hardness could be induced on the surface of treated specimens. However, surface deformation and surface roughness of treated specimens can also increase.
Boron nitride-palladium nanostructured catalyst: efficient reduction of nitrobenzene derivatives in water
Authors: Nayebi Behnam , Rabiee Navid , Nayebi Behzad , Shahedi Asl Mehdi , Ramakrishna Seeram , Jang Ho Won , Varma Rajender S , Shokouhimehr Mohammadreza
Published: October 2020

Boron nitride (BN) supported palladium (Pd) nanostructured catalyst, as an alternative support for heterogeneous reduction of nitrobenzene derivatives, was prepared by a mild reduction of a Pd precursor in water. The structural characteristics and distribution of the synthesized Pd nanoparticles (NPs) on BN support were investigated by transmission electron microscopy, scanning transmission electron microscopy, energy-dispersive x-ray spectroscopy and x-ray photoelectron spectroscopy methods. The potential and efficiency of the BN supported Pd NPs as an active and stable nanostructured catalyst were verified in the reduction of nitroaromatics. Excellent yields of the corresponding aryl amines in water were obtained and due discussion were included about the catalytic activity of the synthesized catalyst. It was also indicated that the nanostructured catalyst can be recycled at least for six consecutive cycles in the reduction of nitrobenzene, without losing significant activity.
Quantifying Native Speakerism in Second Language (L2) Writing: A Study of Student Evaluations of Teaching
Authors: Lee Sei , Du Qian
Published: October 2020

Despite the continually growing number of non-native English-speaking (NNES) teachers in English language teaching, the profession is nonetheless still shaped by native speakerism (Holliday 2005), the idealization of native English speakers (NESs) as linguistically and culturally superior to their NNES counterparts. Such an ideology leads to negative perceptions toward NNES faculty even if they hold equal qualifications to their NES counterparts. This study sought to determine whether multilingual students themselves evaluate instructors differently based on the instructors’ language background. Based on 5,050 Student Evaluation of Teaching (SET) scores compiled over three years (2015–18), independent t-tests and MANCOVA analysis revealed a statistically significant relationship between NNES students’ perceptions of teacher effectiveness and instructor’s language background. Such findings were further compounded by instructor’s gender and course variables, additionally disadvantaging NNES instructors. The broader implications are for institutional stakeholders to be cognizant of the prevalence of native speakerism in L2 writing contexts and use holistic models for teacher assessment to adapt more equitable approaches to assessing underrepresented faculty.
Morphosyntactic Challenges for Swedish-Speaking Children with Developmental Language Disorder in Comparison with L1 and L2 Peers
Authors: Reuterskiöld Christina , Hallin Anna Eva , Nair Vishnu K K , Hansson Kristina
Published: October 2020

This article provides an overview of the research on morpho-syntactic challenges in Swedish-speaking children with developmental language disorder (DLD), compared with typically developing (TD) children learning Swedish as their first and second language (L1/L2). Children with DLD show vulnerabilities with verb finiteness, the possessive construction, and noun phrase gender agreement, as well as word-order in nonsubject initiated sentences. For L2-learners, word order and the noun phrase gender agreement present main challenges. We discuss to what extent these morpho-syntactic weaknesses can be explained by different theoretical accounts and identify future research needs. Surface similarities between groups may originate from different factors and more knowledge is needed to inform educational and clinical practice for both of these groups of children.
Cats and Apples: Semantic Fluency Performance for Living Things Identifies Patients with Very Early Alzheimer’s Disease
Authors: Krumm Sabine , Berres Manfred , Kivisaari Sasa L , Monsch Andreas U , Reinhardt Julia , Blatow Maria , Kressig Reto W , Taylor Kirsten I
Published: October 2020

Objective: Reduced semantic memory performance is a known neuropsychological marker of very early Alzheimer’s disease (AD), but the task format that best predicts disease status is an open question. The present study aimed to identify the semantic fluency task and measure that best discriminates early-stage AD patients (PATs) from cognitively healthy controls. Method: Semantic fluency performance for animals, fruits, tools, and vehicles was assessed in 70 early-stage AD PATs and 67 cognitively healthy participants. Logistic regressions and receiver operating characteristics were calculated for five total score semantic fluency measures. Results: Compared with all other measures, living things (i.e., total correct animals + total correct fruits) achieved highest z-statistics, highest area under the curve and smallest difference between the upper and lower 95% confidence intervals. Conclusion: Living things total correct is a powerful tool to detect the earliest signs of incipient AD.