bluuebunny/crossref_metadata_2025 huggingface dataset:
Cold starting temperature time-related compensation model of inertial sensors based on particle swarm optimization algorithm
Authors: Wu Junqing , Huang Tiantian , Zhu Zhijuan , Song Kaichen
Published: June 2021

With the miniaturization of inertial instruments, sensors mounted inside are vulnerable to interference. In a complex thermal transmission environment, temperature drift is the main factor restricting the precision of high-performance inertial sensors. To solve this problem, a new method for compensating the time-related cold starting temperature drift of the inertial sensors is introduced in this paper. Based on the perspective that temperature drift can be regarded as the response curve of the sensor system to temperature and temperature gradient, temperature compensation models of first-order, second-order, and higher-order are proposed. Meanwhile, the particle swarm optimization algorithm is used to solve the model parameters. Under various practical circumstances, the method can be used to flexibly compensate the temperature drift and reduce the standard deviation of the output signal by about four times. Compared to other models or algorithms, the simulation and experimental results indicate that the proposed model is superior in adaptability, stability, and reliability.
Spatio-temporal correlation functions in scalar turbulence from functional renormalization group
Authors: Pagani Carlo , Canet Léonie
Published: June 2021

We provide the leading behavior at large wavenumbers of the two-point correlation function of a scalar field passively advected by a turbulent flow. We first consider the Kraichnan model, in which the turbulent carrier flow is modeled by a stochastic vector field with a Gaussian distribution, and then a scalar advected by a homogeneous and isotropic turbulent flow described by the Navier–Stokes equation, under the assumption that the scalar is passive, i.e., that it does not affect the carrier flow. We show that at large wavenumbers, the two-point correlation function of the scalar in the Kraichnan model decays as an exponential in the time delay, in both the inertial and dissipation ranges. We establish the expression, both from a perturbative and from a nonperturbative calculation, of the prefactor, which is found to be always proportional to k2. For a real scalar, the decay is Gaussian in t at small time delays, and it crosses over to an exponential only at large t. The assumption of delta-correlation in time of the stochastic velocity field in the Kraichnan model, hence, significantly alters the statistical temporal behavior of the scalar at small times.
Multiple active voltage stabilizations for multi-reflection time-of-flight mass spectrometry
Authors: Fischer Paul , Schweikhard Lutz
Published: June 2021

The performance of a multi-reflection time-of-flight (MR-ToF) mass spectrometer is evaluated under the use of four voltage feedback loops to actively regulate its mirror potentials. Different electronic hardware is characterized to find the most useful configuration for parallel regulation of all of the MR-ToF analyzer’s reflecting potentials. The gain in mass resolving power for low-abundance ion species is demonstrated by measuring pairs of molecular isobars of zinc clusters and analyzed in the context of expected flight-time fluctuations. For higher-abundance species, the resolving powers reached in short- and long-term measurements are probed with bismuth-cluster ions, resulting in values up to 500 000 and 200 000, respectively, in the absence of offline corrections. Additionally, feedback-loop regulation is found to be advantageous for changes of experiment cycles in which voltages are switched for, e.g., ion ejection.
Effects of outlets flow rates ratios on flow patterns in cross-shaped channels
Authors: Zhang Wei , Li Wei-feng , Liu Hai-feng , Wang Fu-chen
Published: June 2021

Flow patterns in a cross-shaped channel with two inlets and two outlets at 30 < Re < 350 were identified by plane laser induced fluorescence. The effects of outlets flow rates ratio (M, defined as the ratio of flow rates at two outlets) on flow regimes were investigated. For M = 1, four distinct flow regimes emerge in turns with increasing Reynolds number (Re), including a segregated flow, a steady engulfment flow, a vortex shedding oscillation, and an unsteady engulfment flow. For 1 < M ≤ 2, flow regimes remain unchanged, but the symmetry of the flow topologies is broken. Despite small outflow imbalance, the structures of recirculation regions originated from vortex breakdown are shifted significantly. For 2 < M < 20, the unsteady engulfment flow disappears and the critical Reynolds number of the vortex shedding oscillation decreases, leading to an increase in the Reynolds number ranges of the vortex shedding oscillation. Further increasing M, an oscillation of vortex merging occurs. The characteristics of the vortex shedding oscillation and the vortex merging oscillation are revealed and their mechanisms are discussed. Especially for M→∞, the inlet fluids preserved are segregated along the outlet channel in the Reynolds number ranges of the current experiment.
AIMSWISS—Ab initio multiple spawning with informed stochastic selections
Authors: Lassmann Yorick , Curchod Basile F. E.
Published: June 2021

Ab initio multiple spawning (AIMS) offers a reliable strategy to describe the excited-state dynamics and nonadiabatic processes of molecular systems. AIMS represents nuclear wavefunctions as linear combinations of traveling, coupled Gaussians called trajectory basis functions (TBFs) and uses a spawning algorithm to increase as needed the size of this basis set during nonadiabatic transitions. While the success of AIMS resides in this spawning algorithm, the dramatic increase in TBFs generated by multiple crossings between electronic states can rapidly lead to intractable dynamics. In this Communication, we introduce a new flavor of AIMS, coined ab initio multiple spawning with informed stochastic selections (AIMSWISS), which proposes a parameter-free strategy to beat the growing number of TBFs in an AIMS dynamics while preserving its accurate description of nonadiabatic transitions. The performance of AIMSWISS is validated against the photodynamics of ethylene, cyclopropanone, and fulvene. This technique, built upon the recently developed stochastic-selection AIMS, is intended to serve as a computationally affordable starting point for multiple spawning simulations.
Aqueous choline amino acid deep eutectic solvents
Authors: Miao Shurui , Jiang Haihui Joy , Imberti Silvia , Atkin Rob , Warr Gregory
Published: June 2021

We have investigated the structure and phase behavior of biocompatible, aqueous deep eutectic solvents by combining choline acetate, hydrogen aspartate, and aspartate amino acid salts with water as the sole molecular hydrogen bond donor. Using contrast-variation neutron diffraction, interpreted via computational modeling, we show how the interplay between anion structure and water content affects the hydrogen bond network structure in the liquid, which, in turn, influences the eutectic composition and temperature. These mixtures expand the current range choline amino acid ionic liquids under investigation for biomass processing applications to include higher melting point salts and also explain how the ionic liquids retain their desirable properties in aqueous solution.
Role of wire diameter size in the high voltage pulse wire explosion: Insights from molecular dynamics simulations
Authors: Pu Yanxu , Lv Fangwei , Sun Xinfeng , Zhang Tianping , Qi Hui , Geng Hai , Wu Chenchen , Cheng Xinwei
Published: June 2021

We performed molecular dynamics simulations of the high voltage pulse explosion of single aluminum wires with the energy ratio of 0.6 in vacuum and studied the role of wire radial dimension. Simulation results show that large-diameter wires having a large material depth and a small specific surface can maintain a higher deposition energy density and effectively reduce the influence of the radial difference in thermodynamic parameters, leading to higher explosion velocity and a lower vaporization rate in the large-diameter wire. The most significant effect is that the larger diameter wire has a longer explosion development time. In addition, the propagation and reflection of the rarefaction waves in the wire result in two explosion regimes: the spinodal decomposition propagating inward from the surface and the cavitation boiling from the center to the surface. Increasing the diameter will increase the domination range of the spinodal decomposition mechanism.
Barrier-dependent electronic transport properties in two-dimensional MnBi2Te4-based van der Waals magnetic tunnel junctions
Authors: Yan Zhi , Jia Xin , Shi Xiaowen , Dong Xinlong , Xu Xiaohong
Published: June 2021

Tunneling magnetoresistance (TMR) and spin filtering effects in the magnetic tunnel junctions (MTJs) have drawn much attention for potential spintronic applications based on magnetic manipulation of electric transport. However, the traditional MTJs cannot meet the demand for rapid miniaturization of electronic components. Thus, van der Waals (vdW) MTJs with a few atomic layers stacked vertically are ideal candidates for atomic scale devices. In this work, by employing the non-equilibrium Green's function combined with density-functional theory, we systemically study the spin-dependent electronic transport properties across MnBi2Te4 (MBT)-based vdW MTJs with three typical barrier layers, i.e., monolayer hexagonal boron nitride (h-BN), monolayer graphene, and vacuum. By using graphite as the electrode of these junctions, we find that a high TMR ratio up to 4000% and almost 100% spin filtering ratio are realized in MBT|h-BN|MBT MTJ at low bias voltages. Moreover, a remarkable negative differential resistance effect is observed in MBT|h-BN|MBT and MBT|Graphene|MBT junctions. The observed barrier-dependent quantum transport phenomenon is explained by the transmission coefficient. Our unique design of these vdW structures reasonably overcomes the bottleneck of current leakage and avoids the interface contact issues and paves the way for the exploration of spintronics devices with better performance.
Active controllable spin-selective terahertz asymmetric transmission based on all-silicon metasurfaces
Authors: Li Jitao , Li Jie , Zheng Chenglong , Yue Zhen , Wang Silei , Li Mengyao , Zhao Hongliang , Zhang Yating , Yao Jianquan
Published: June 2021

A strong spin-selective asymmetric transmission metasurface usually relies on a multilayer metal frame or compound all-dielectric system. By contrast, an all-silicon metasurface has advantages of simple process, low cost, and easy optical modulation. However, there is little work to explore the spin-selective asymmetric transmission in terahertz band based on the all-silicon metasurface due to weak interaction between all-silicon materials and terahertz waves. Herein, we have achieved excellent spin-selective terahertz asymmetric transmission in the all-silicon metasurface by the ingenious chirality structure design, and the maximum circular dichroism can reach 0.4. Meanwhile, 1064 nm continuous wave optical pumping modulates the asymmetric transmission amplitude of the all-silicon metasurface to achieve circular dichroism switch between “On” and “Off.” We have also developed terahertz chiral imaging applications based on the all-silicon metasurface with spin-selective asymmetric transmission, and the chiral imaging with On and Off switching characteristics can be realized via optically active control.
Evaluating the roles of temperature-dependent eigenvectors in predicting phonon transport properties of anharmonic crystals using normal mode analysis methods
Authors: He Jixiong , Liu Jun
Published: June 2021

Theoretical modeling of phonon transport process in strongly anharmonic materials at a finite temperature needs to accurately capture the effects of lattice anharmonicity. The anharmonicity of potential energy surface would result in not only strong phonon scatterings but also shifts of phonon frequencies and eigenvectors. In this work, we evaluated the roles of anharmonicity-renormalized phonon eigenvectors in predicting phonon transport properties of anharmonic crystals at high temperatures using molecular dynamics-based normal mode analysis (NMA) methods in both time domain and frequency domain. Using PbTe as a model of strongly anharmonic crystal, we analyzed the numerical challenges to extract phonon lifetimes using NMA methods when phonon eigenvectors deviate from their harmonic values at high temperatures. To solve these issues, we proposed and verified a better fitting strategy, Sum-up Spectrum Fitting Method (SSFM) than the original frequency-domain NMA method. SSFM is to project the total spectrum energy density data of all phonon modes onto an inaccurate (harmonic or quasi-harmonic) eigenvector base and then manually sum up the peaks that belong to the same phonon mode (at the same frequency). The SSFM relaxes the requirement for accurate temperature-dependent eigenvectors, making it robust for analyzing strongly anharmonic crystals at high temperatures.
SARS CoV-2 aerosol: How far it can travel to the lower airways?
Authors: Islam Mohammad S. , Larpruenrudee Puchanee , Paul Akshoy Ranjan , Paul Gunther , Gemci Tevfik , Gu Yuantong , Saha Suvash C.
Published: June 2021

The recent outbreak of the SARS CoV-2 virus has had a significant effect on human respiratory health around the world. The contagious disease infected a large proportion of the world population, resulting in long-term health issues and an excessive mortality rate. The SARS CoV-2 virus can spread as small aerosols and enters the respiratory systems through the oral (nose or mouth) airway. The SARS CoV-2 particle transport to the mouth–throat and upper airways is analyzed by the available literature. Due to the tiny size, the virus can travel to the terminal airways of the respiratory system and form a severe health hazard. There is a gap in the understanding of the SARS CoV-2 particle transport to the terminal airways. The present study investigated the SARS CoV-2 virus particle transport and deposition to the terminal airways in a complex 17-generation lung model. This first-ever study demonstrates how far SARS CoV-2 particles can travel in the respiratory system. ANSYS Fluent solver was used to simulate the virus particle transport during sleep and light and heavy activity conditions. Numerical results demonstrate that a higher percentage of the virus particles are trapped at the upper airways when sleeping and in a light activity condition. More virus particles have lung contact in the right lung than the left lung. A comprehensive lobe specific deposition and deposition concentration study was performed. The results of this study provide a precise knowledge of the SARs CoV-2 particle transport to the lower branches and could help the lung health risk assessment system.
Improved uniformity in resistive switching behaviors based on PMMA films with embedded carbon quantum dots
Authors: Li Liye , Liu Binglin , Feng Julin , Hu Wei , Lin Hao , Huang Yanyi , Wu Daofu , Zeng Fanju , Zhou Jiaer , Tang Xiaosheng
Published: June 2021

The growth and rupture of conductive filaments act a crucial part in the reliability of resistive switching behaviors. The random growth and rupture of conductive filaments are the primary reason for the instability of set/reset reproducibility. Hence, we propose a method that embedded carbon quantum dots (CQDs) in polymethylmethacrylate (PMMA) to fabricate the Ag/PMMA&CQDs/FTO resistive switching device. Five different concentrations of CQDs are embedded in PMMA to regulate the resistive switching properties, and the resistive memory characteristics of the optimal group are systematically studied. The optimal group exhibits excellent switching repeatability, low set/reset voltages, and stable forming voltage, which is much better than PMMA without CQDs. Furthermore, we employ the COMSOL software to build a simulation model for exploring the influence of CQDs on the internal electric field of PMMA, which proved that the introduction of CQDs might have a favorable effect on the orderly growth of conductive filaments.
Fully epitaxial ferroelectric ScAlN grown by molecular beam epitaxy
Authors: Wang Ping , Wang Ding , Vu Nguyen M. , Chiang Tony , Heron John T. , Mi Zetian
Published: June 2021

We report on the demonstration of ferroelectricity in ScxAl1-xN grown by molecular beam epitaxy on GaN templates. Distinct polarization switching is unambiguously observed for ScxAl1-xN films with Sc contents in the range of 0.14–0.36. Sc0.20Al0.80N, which is nearly lattice-matched with GaN, exhibiting a coercive field of ∼ 4.2 MV/cm at 10 kHz and a remnant polarization of ∼135 μC/cm2. After electrical poling, Sc0.20Al0.80N presents a polarization retention time beyond 105 s. No obvious fatigue behavior can be found with up to 3 × 105 switching cycles. The work reported here is more than a technical achievement. The realization of ferroelectric single-crystalline III–V semiconductors by molecular beam epitaxy promises a thickness scaling into the nanometer regime and makes it possible to integrate high-performance ferroelectric functionality with well-established semiconductor platforms for a broad range of electronic, optoelectronic, and photonic device applications.
Analysis of an integrated thermal management system with a heat-pump in a fuel cell vehicle
Authors: Zhao Zhen , Wang Tie , Zhang Baifu , Wang Yiquan , Bao Chunjiang , Ji Zhiyong
Published: June 2021

Fuel cell vehicles (FCVs) are becoming increasingly popular because they are both environmentally friendly and energy efficient. However, because no waste heat from the internal combustion engine can be used, the additional electricity needed to heat the cabin in cold weather increases the energy consumption substantially. This also lowers both the fuel economics and driving range. The required additional heating is typically done with a positive temperature coefficient (PTC) electric heater. To overcome the associated performance problem, a novel vehicle-integrated thermal management system (VTMS) with a heat-pump system is developed and investigated in this study. Using a simulation, the performance of the VTMS is investigated with respect to cooling performance, heating performance, and heating energy consumption for several different heat sources. For four different driving cycles, the equivalent hydrogen consumption (EHC) is highest when the PTC heater is used. The heat-pump system, which uses waste heat generated by a proton exchange membrane fuel cell, shows the lowest EHC. The results reveal that the use of a heat-pump heating system with waste heat can reduce hydrogen consumption by ∼14.6%, 6.5%, 16.9%, and 16.7% compared to PTC heating. Furthermore, the driving ranges increased by 17.2, 6.8, 20.3, and 12.6 km per 100 km, respectively. The VTMS, thanks to its ability to reduce energy consumption effectively, makes it possible to improve the thermal comfort in the vehicle cabin, which is especially useful for the commercialization of FCVs.
Genomics-informed models reveal extensive stretches of coastline under threat by an ecologically dominant invasive species
Authors: Hudson Jamie , Castilla Juan Carlos , Teske Peter R. , Beheregaray Luciano B. , Haigh Ivan D. , McQuaid Christopher D. , Rius Marc
Published: June 2021

Significance

Species with narrow distributions provide unique opportunities for understanding the mechanisms that limit their spread. We studied a marine invader that exhibits ecological dominance within its range and has the capacity to fundamentally alter the coastal habitat when introduced to new locations. We found evidence of the species’ potential to establish itself far beyond its present introduced range from both genomic data and species distribution modeling. Therefore, minor oceanographic changes (due to, for example, contemporary climate change) or alteration to human-mediated dispersal may trigger a large-scale invasion along vast stretches of coastlines. Our work provides a holistic framework to assess potential changes in the distribution of invasive species.
Dopaminergic neuromodulation of prefrontal cortex activity requires the NMDA receptor coagonist
d
-serine
Authors: Dallérac Glenn , Li Xia , Lecouflet Pierre , Morisot Nadège , Sacchi Silvia , Asselot Rachel , Pham Thu Ha , Potier Brigitte , Watson David J. G. , Schmidt Staffan , Levasseur Grégoire , Fossat Pascal , Besedin Andrey , Rivet Jean-Michel , Coyle Joseph T. , Collo Ginetta , Pollegioni Loredano , Kehr Jan , Galante Micaela , Fone Kevin C. , Gardier Alain M. , Freret Thomas , Contarino Angelo , Millan Mark J. , Mothet Jean-Pierre
Published: June 2021

Significance

Dopamine and glutamate in the prefrontal cortex are important substrates of higher cognitive functions, which are impaired in neuropsychiatric disorders. As regards glutamatergic pathways, a role for the NMDA receptor coagonist
d
-serine has been highlighted, yet its relationship to dopaminergic transmission remains unclear. In this study, we reveal that
d
-serine plays a pivotal role in the modulation by dopamine of NMDA receptor activity and cognitive performance in the prefrontal cortex. Comprehensive evidence for this interaction is provided at the synaptic, neuronal, network, and behavioral levels. These observations are of relevance to the pathophysiology and treatment of cognitive impairment in numerous disorders involving disruption of the frontocortical dialogue between dopamine and glutamate.
LRRC8A-containing chloride channel is crucial for cell volume recovery and survival under hypertonic conditions
Authors: Serra Selma A. , Stojakovic Predrag , Amat Ramon , Rubio-Moscardo Fanny , Latorre Pablo , Seisenbacher Gerhard , Canadell David , Böttcher René , Aregger Michael , Moffat Jason , de Nadal Eulàlia , Valverde Miguel A. , Posas Francesc
Published: June 2021

Significance

Rapid regulatory volume increase (RVI) is important for cell survival under hypertonic conditions. RVI is driven by Cl
−
uptake via the Na–K–Cl cotransporter (NKCC), which is activated by WNK kinases following a reduction in intracellular [Cl
−
]. However, how intracellular [Cl
−
] is regulated to modulate the WNK–NKCC axis and engage a protective RVI remains unknown. Our work reveals that LRRC8A-containing chloride channel is a key protective factor against hypertonic shocks. Considering that LRRC8A (SWELL1) is typically activated by low ionic strength under hypotonic stress, our results posed another interesting question: what activates this chloride channel under hypertonic stress? We demonstrated that, upon hyperosmotic activation, the p38-MSK1 pathway gates LRRC8A-containing chloride channel to facilitate activation of WNK–NKCC and an effective RVI.
Structure and function at the lipid–protein interface of a pentameric ligand-gated ion channel
Authors: Kumar Pramod , Cymes Gisela D. , Grosman Claudio
Published: June 2021

Significance

The preparation of membrane-protein specimens for structural characterization commonly involves a detergent-solubilization step that is sometimes followed by the reincorporation of the protein into laboratory-made lipid nanodiscs. Whether the native conformation and arrangement of tightly bound lipids are retained despite solubilization or restored upon nanodisc formation cannot be predicted. To determine the structure of the bacterial pentameric ligand-gated ion channel ELIC in its native environment, we overexpressed it inEscherichia coli, fragmented the inner membranes into disc-shaped structures in the absence of detergents, purified discs containing single copies of the protein, and imaged the resulting particles using cryogenic electron microscopy. The obtained three-dimensional reconstruction of the unliganded channel (2.5-Å resolution) revealed previously unseen details of the lipid–protein interface.
Spatial distribution of LTi-like cells in intestinal mucosa regulates type 3 innate immunity
Authors: Sécca Cristiane , Bando Jennifer K. , Fachi José L. , Gilfillan Susan , Peng Vincent , Di Luccia Blanda , Cella Marina , McDonald Keely G. , Newberry Rodney D. , Colonna Marco
Published: June 2021

Significance

The lymphoid tissue inducer (LTi)-like cell is a specialized innate lymphocyte that produces cytokines that promote intestinal epithelial barrier integrity and protective immunity against pathogenic bacteria. Here, we report that the spatial positioning of LTi-like cells within intestinal mucosa enables them to receive signals that control their activity. Deletion of the LTi-like cell chemokine receptor CXCR5 displaced LTi-like cells from their natural niche in gut mucosa and enhanced their capacity to produce cytokines upon activation. LTi-like cell hyperresponsiveness in
Cxcr5
-deficient mice strongly improved gut barrier integrity and protected mice during infection with the human opportunistic pathogen
Clostridium difficile
. Our findings demonstrate that the specialized positioning of LTi-like cells within the gut mucosa controls their activity and impacts protective immunity.
Exploring conceptions of reading risk and program-specific literacy outcomes for Spanish speakers in dual language and English-medium programs
Authors: Neugebauer Sabina Rak , Howard Elizabeth R.
Published: June 2021

Considerable research documents the efficacy of dual language programs for the reading achievement of English learners from Spanish-speaking homes. However, there is uncertainty in the field of dual language education about how students at-risk for literacy difficulties fare in these same programs, as well as questions about how risk should be defined – i.e., difficulty with decoding versus lower levels of vocabulary – with distinct understandings of risk potentially differentially explaining students’ reading trajectories. This study followed Spanish-speaking students from Grades 3–5 to understand how students at-risk for reading difficulties fare in English reading comprehension in dual language versus English-medium programs, examining two different risk indicators in the process. Study results indicate that across risk categories, students performed equally well regardless of program model. In addition, decoding was a more robust indicator of risk than vocabulary.
Audio and vestibular analyses in patient with multiple sclerosis
Authors: Delphi Maryam , Sayaf Maryam , Taheri Fatemeh , Majdinasab Nastaran
Published: June 2021

Background

Multiple sclerosis (MS) is a neurologic demyelinating disease that affects the brain and spinal cord. As well, Brainstem involvement is common in MS. Auditory and vestibular tests are included in the methods that can be used to examine the brainstem. So, this study aimed to evaluate brainstem in MS patients using MLD, ABR, and VEPM as well as demonstrating the predictor factors in MLD, ABR, and VEPM tests for MS occurrence.

Methods

In this cross-sectional study, MLD, ABR, and VEPM were recorded in 25 healthy individuals and 25 MS patients aged between 18 and 45 years old. MS diagnosis was made by a neurologist using the McDonald's criterion. The obtained data were analysed using SPSS.

Result

A significant difference was observed among the latency of III, V, interpeak intervals I–III, III–V, I–V, V/I ratio in ABR, P13, and N23 in VEMP, and MLD value in the two groups (p < .05). The latency of V, P13, N23, V/I ratio, and MLD were also found to be associated with the occurrence of MS.

Conclusion

latency of V, P13, N23, V/I ratio, and MLD appear to be predictors of the occurrence of MS; therefore, auditory brainstem tests such as MLD, ABR, and VEPM can be considered as useful tools for detecting early lesions in MS patients.
Giant Rashba-like spin–orbit splitting with distinct spin texture in two-dimensional heterostructures*
Authors: Zhu Jianbao , Qin Wei , Zhu Wenguang
Published: June 2021

Based on first-principles density functional theory calculation, we discover a novel form of spin-orbit (SO) splitting in two-dimensional (2D) heterostructures composed of a single Bi(111) bilayer stacking with a 2D semiconducting In2Se2 or a 2D ferroelectric α-In2Se3 layer. Such SO splitting has a Rashba-like but distinct spin texture in the valence band around the maximum, where the chirality of the spin texture reverses within the upper spin-split branch, in contrast to the conventional Rashba systems where the upper branch and lower branch have opposite chirality solely in the region below the band crossing point. The ferroelectric nature of α-In2Se3 further enables the tuning of the spin texture upon the reversal of the electric polarization with the application of an external electric field. Detailed analysis based on a tight-binding model reveals that such SO splitting texture results from the interplay of complex orbital characters and substrate interaction. This finding enriches the diversity of SO splitting systems and is also expected to promise for spintronic applications.
Optical absorption tunability and local electric field distribution of gold-dielectric-silver three-layered cylindrical nanotube*
Authors: Ma Ye-Wan , Wu Zhao-Wang , Jiang Yan-Yan , Li Juan , Yin Xun-Chang , Zhang Li-Hua , Yi Ming-Fang
Published: June 2021

The effects of inner nanowire radius, shell thickness, the dielectric functions of middle layer and surrounding medium on localized surface plasmon resonance (LSPR) of gold-dielectric-silver nanotube are studied based on the quasi-staticapproximation. Theoretical calculation results show that LSPR of gold-dielectric-silver nanotube and LSPR numbers can bewell optimized by adjusting its geometrical parameters. The longer wavelength of

|

ω
−
−

〉

mode takes place a distinct red-shift with increasing the inner nanowire radius and the thickness of middle dielectric layer,while a blue-shift with increasing outer nanotube thickness. The physical mechanisms are explained based on the plasmon hybridization theory, induced charges and phase retardation. In addition, the effects of middle dielectric function and surrounding medium on LSPR, and the local electric field factor are also reported. Our study provides the potential appications of gold-dielectric-silver nanotube in biological tissues, sensor and related regions.
Magnetocrystalline anisotropy and dynamic spin reorientation of half-doped Nd0.5Pr0.5FeO3 single crystal*
Authors: Zhai Haotian , Gao Tian , Zheng Xu , Li Jiali , Chen Bin , Dong Hongliang , Chen Zhiqiang , Zhao Gang , Cao Shixun , Cai Chuanbing , Marchenkov Vyacheslav V.
Published: June 2021

The single crystals of Nd0.5Pr0.5FeO3 were successfully grown by optical floating zone method. Room temperature x-ray diffraction and Laue photograph declared the homogeneity and high quality of the crystal. The significant magnetic anisotropy and multiple magnetic transitions illustrate the complex magnetic structure. At high temperatures (T > 66 K), it shows the typical characteristics of Γ
4(G
x
, A
y
, F
z
) state. With the decrease of the temperature, it undergoes a first-order spin reorientation transition from Γ
4(G
x
, A
y
, F
z
) to Γ
2(F
x
, C
y
, G
z
) state in the temperature window of 45–66 K under an applied magnetic field of 0.01 T. As the temperature drops to ∼ 17 K, a new magnetic interaction mechanism works, which results in a further enhancement of magnetization. The T–H phase diagram of Nd0.5Pr0.5FeO3 single crystal was finally constructed.
A low noise, high fidelity cross phase modulation in multi-level atomic medium*
Authors: Wang Liangwei , Guan Jia , Zhu Chengjie , Li Runbing , Shi Jing
Published: June 2021

We develop a hybrid scheme of cross phase modulation based on electromagnetically induced transparency (EIT) and active Raman gain (ARG) in a multi-level atomic medium. The cross phase modulation, with low loss and without noise, is demonstrated in a room-temperature 85Rb vapor. We show that a π radian nonlinear Kerr phase shift of the signal light relative to a reference light is observed when the signal light is modulated by the phase control field with the low light intensity. We also show that the linear and the third-order absorption can be eliminated via the Raman gain, and the phase noise of the signal light can be ignored when the phase control light is applied in this hybrid scheme.
Oxygen vacancy control of electrical, optical, and magnetic properties of Fe0.05Ti0.95O2 epitaxial films*
Authors: Xia Qing-Tao , Li Zhao-Hui , Zhang Le-Qing , Zhang Feng-Ling , Li Xiang-Kun , Liu Heng-Jun , Gu Fang-Chao , Zhang Tao , Li Qiang , Li Qing-Hao
Published: June 2021

High-quality Fe-doped TiO2 films are epitaxially grown on MgF2 substrates by pulsed laser deposition. The x-ray diffraction and Raman spectra prove that they are of pure rutile phase. High-resolution transmission electron microscopy (TEM) further demonstrates that the epitaxial relationship between rutile-phased TiO2 and MgF2 substrates is 110 TiO2 ∥ 110 MgF2. The room temperature ferromagnetism is detected by alternative gradient magnetometer. By increasing the ambient oxygen pressure, magnetization shows that it decreases monotonically while absorption edge shows a red shift. The transport property measurement demonstrates a strong correlation between magnetization and carrier concentration. The influence of ambient oxygen pressure on magnetization can be well explained by a modified bound magnetization polarization model.
Micro-pinch formation and extreme ultraviolet emission of laser-induced discharge plasma*
Authors: Wang Jun-Wu , Wang Xin-Bing , Zuo Du-Luo , Zakharov Vassily S.
Published: June 2021

Extreme ultraviolet (EUV) source produced by laser-induced discharge plasma (LDP) is a potential technical means in inspection and metrology. A pulsed Nd:YAG laser is focused on a tin plate to produce an initial plasma thereby triggering a discharge between high-voltage electrodes in a vacuum system. The process of micro-pinch formation during the current rising is recorded by a time-resolved intensified charge couple device camera. The evolution of electron temperature and density of LDP are obtained by optical emission spectrometry. An extreme ultraviolet spectrometer is built up to investigate the EUV spectrum of Sn LDP at 13.5 nm. The laser and discharge parameters such as laser energy, voltage, gap distance, and anode shape can influence the EUV emission.
Actively tunable dual-broadband graphene-based terahertz metamaterial absorber*
Authors: Hu Dan , Meng Tian-Hua , Wang Hong-Yan , Fu Mai-Xia
Published: June 2021

A tunable metamaterial absorber (MA) with dual-broadband and high absorption properties at terahertz (THz) frequencies is designed in this work. The MA consists of a periodic array of flower-like monolayer graphene patterns at top, a SiO2 dielectric spacer in middle, and a gold ground plane at the bottom. The simulation results demonstrate that the designed MA has two wide absorption bands with an absorption of over 90% in frequency ranges of 0.68 THz–1.63 THz and 3.34 THz–4.08 THz, and the corresponding relative bandwidths reach 82.3% and 20%, respectively. The peak absorptivity of the absorber can be dynamically controlled from less than 10% to nearly 100% by adjusting the graphene chemical potential from 0 eV to 0.9 eV. Furthermore, the designed absorber is polarization-insensitive and has good robustness to incident angles. Such a high-performance MA has broad application prospects in THz imaging, modulating, filtering, etc.
Spin transport properties for B-doped zigzag silicene nanoribbons with different edge hydrogenations
Authors: Zhao Jing-Fen , Wang Hui , Yang Zai-Fa , Gao Hui , Bu Hong-Xia , Yuan Xiao-Juan
Published: June 2021

Exploring silicon-based spin modulating junction is one of the most promising areas of spintronics. Using nonequilibrium Green’s function combined with density functional theory, a set of spin filters of hydrogenated zigzag silicene nanoribbons is designed by substituting a silicon atom with a boron one and the spin-correlated transport properties are studied. The results show that the spin polarization can be realized by structural symmetry breaking induced by boron doping. Remarkably, by tuning the edge hydrogenation, it is found that the spin filter efficiency can be varied from 30% to 58%. Moreover, it is also found and explained that the asymmetric hydrogenation can give rise to an obvious negative differential resistance which usually appears at weakly coupled junction. These findings indicate that the boron-doped ZSiNR is a promising material for spintronic applications.
The role of astronomical silicates during a cometary outburst
⋆
Authors: Wesołowski Marcin
Published: June 2021

This paper presents a new approach to analyzing the change of cometary brightness. In our considerations, we assume that astronomical silicates (dust agglomerates) and gas are present in the coma. This assumption is a consequence of the analysis of the result observed during the Rosetta mission to comet 67P/Churyumov-Gerasimenko (abbreviated 67P/Ch-G). The dimensions of these agglomerates can be up to several centimeters. However, the large ones are few compared to particles with dimensions of several micrometers. This paper presents the results of calculations on the change in hypothetical comet brightness as a result of its outburst. The calculations take into account the percentage of carbonaceous particles and silicates rich in magnesium.
Using GIS technology for land suitability analysis to select drainage project location: Nasiriya city south of Iraq as a case study
Authors: Mohammed Haidar Razzaq , Alkanaani Hayder A , Alowaid Humam K
Published: June 2021

The main aim of this paper is to produce a theoretical basis for the selection of drainage project location by using the GIS technology’. Nasirya city that located in the southern part of Iraq has been selected as a case study. The site must be ideally chosen where it must be subjected to specified standards. The model of a suitable site was constructed utilizing a model developer in ArcGIS. It was assembled dependent on the spatial system which is known as the weighted linear combination. The final suitable maps were produced by coordinating different models. In this work, the feature of exactness in the determination of the most fitting site for the foundation of the drainage venture, which is viewed as one of most significant elements that lead to extend the arable area. Thus process should be the basic leadership for the choice of the most appropriate site as indicated by strict procedures and consistent choice. The outcomes result from the procedure suggested that six areas were chosen according to indicated factors. The scores were depended on experts and literature. The Locations were determined in the examination zone by embracing the GIS incorporated Analytic Hierarchy Process. The most suitable areas among them for the development of drainage venture ‘serving the rural regions as indicated by spatial analysis were picked dependent on the characteristics of the proposed area. The proposed location no 3 was the best of them where it fulfils all factors firmly. Unsustainable administration prompts a horrible impact on arable area and results in the loss of the appropriate strategy. The mistake in the choice of the most reasonable site for the venture not only lead to pressure on the system but also a collapse in the water system framework of the agricultural reality of the country.
Finite element analysis of seepage for Kongele earth dam Using Geo- Studio software
Authors: Th Al-Hadidi M , Hashim S H
Published: June 2021

Seepage occurs under or inside structures or in the place, where they come into contact with the sides under the influence of pressure caused by the difference in water level in the structure U / S and D / S. This paper is designed to model seepage analysis for Kongele (an earth dam) due to its importance in providing water for agricultural projects and supporting Tourism sector. For this purpose, analysis was carried out to study seepage through the dam under various conditions. Using the finite element method by computer program (Geo-Studio) the dam was analysed in its actual design using the SEEP / W 2018 program. Several analyses were performed to study the seepage across Kongele dam in several cases, including when the reservoir was empty, and at the normal and maximum water level. The final results of the analysis show that the dam is safe.
Change monitoring and assessment of health capacity of Iraq due to COVID-19 by application of GIS techniques
Authors: Al-Khuzaie Marwah M.
Published: June 2021

Infectious disease distribution is fundamentally a spatial process; thus, geospatial data, technology and analysis methods play an essential role in analysing and controlling the 2019 Coronavirus Disease (COVID-19) pandemic. As a result of this virus, there is a rapid increase in the number of infected and deaths distributed in different regions of Iraq. Social functioning, human health, life, human production, and also international relations are extremely threatened by COVID-19. To fight this virus, Geographic Information Systems (GIS) can play an important role in many aspects such as preventing the spread and the evaluating the required measures. GIS is an advanced technique which has a complete method for database, form construction, model construction, and map production geographical health gaps and social weaknesses review, and communicating illness state or return-to-normal operations in hospitals. The use of the GIS has the ability to improve the location and usability of personal security installations, ventilators, hospital beds and other objects. However, strengthen production of GIS to boost our ability to respond rapidly in the face of pandemics that are on the verge of spreading. This study summarizes the main uses of GIS technologies in the global health care sector, highlighting applications related to the modelling and analysis of parasitic diseases. It also allows investigators to connect health public and climate data so that relations of health-related variables and environmental risk factors at various geographical quantities can be analysed.
Estimation of surface temperature using landsat satellite images and geographic information systems for environmental studies in iraq
Authors: Ali Hussain Zaydan
Published: June 2021

The local environment of a city is different for urban area in the center and the surroundings rural. The urban area is 4 to 6 °c warmer than its surroundings rural. Due to changes in urban areas many processes are affected. Like solar radiation absorbed, the temperature of the surface, and the heat stored. The temperature of the land surface gives us important information concerning the physical properties of surface and climate because they plays a great role in many processes in the environment. Sensors in the thermal band onboard satellite can be used to obtain the temperature of the surface. The Surface temperature provides us a great way to monitor the urban environment, and also the activities of human. In this paper the surface temperature was estimated using Landsat satellite data in Iraq. First I extract radiance of the surface using the pixel values (DN) of image. Second the temperature of the surface is calculated from the surface radiance using ArcGIS 10.2. Map of temperature distribution was produced for the study area.
Mechanical and impact properties of concrete slabs reinforced with waste plastic fiber with adding recycled aggregates
Authors: Al-Obaidi Z A
Published: June 2021

In this study, demolished concrete products were used after crushed and replaced with normal coarse aggregate besides the addition of fibers produced from manual chopping of plastic bottles used to preserve soft drinks were used to improve the Impact resistance and some mechanical properties of concrete. Two types of mixes were poured; the first type contains normal coarse aggregate with different fibers ratios, while the second type the normal coarse aggregate was fully replaced by crushed concrete products by adding the same different fibers ratios to the mix. Two reference mixes made for each type of concrete without adding fibers for the purpose of comparison. The results of concrete containing natural coarse aggregate, and fiber added showed a slight decrease in concrete density and an improvement in compression resistance and bending resistance at age (28) days. And improvement in the impact resistance of slabs at age (56) days. The results of concrete containing recycled aggregates and fiber added showed a slight decrease in the density of concrete and an improvement in compression resistance and bending resistance at age (28) days respectively, the impact resistance of the slabs improved at age (56) days.
Rubberized concrete mix – discussions for literature review
Authors: Al-Mutairee Hayder M K , Makki Ola Mazen
Published: June 2021

Using scraped tires in construction nowadays is one of the most effective topics for designers. Due to the capacity of the new material (rubcrete) to convert the behaviour from brittle to completely ductile, enlarge the strain value till failure load, and the mix withstands the nonlinearity stage before total collapse. This paper overviews the literature important results of rubber replacement by aggregates, discussed the behaviour of rubber in the concrete mix, and limitations an approximate indication about the drop in concrete properties after adding rubber. It has been concluded that using rubber weakens the overall compressive strength in a range of (10-50) % for 10% sand replacement. While replacement by 15% almost causes to decrease compressive strength in the range (15-36) % for sand and (30-50) % for gravel. The expected drop in tensile strength for sand replacement by 15% ranged approximately from 20-40%. Replacing sand by 5% leads to increase tensile strength in a range that varies from 5-15%. Gravel replacement by15% caused to minimize strength in a magnitude varies from 20-50%. 15% replacement of sand leads to minimizing the flexural strength in a value range from 14-25%. The average ultimate strain of rubcrete equals two to three times that of conventional concrete.
Properties of no-fines recycled aggregate concrete contains waste plastic fibers
Authors: Al-Obaidi Z A
Published: June 2021

The purpose of this study is to produce recycled concrete from the most common environmental pollutants, which are plastic waste and recycle concrete. Where plastic bottles were cut and used as fibers to reinforce concrete besides using the recycle concrete as an aggregate. also, it can be used in improving the various properties of concrete in terms of improving compressive strength, bending, thermal insulation, etc., because it is considered one of the most influencing disadvantages of concrete. Five mixes of concrete free of fine aggregate were poured with various volumetric proportions (0.6, 0.8, 1.0, 1.2 and 1.4) % of plastic fibers were added to them. The natural aggregate was completely replaced by a carefully graded product according to the specifications of crushed concrete residue. A comparative mix of recycled fiber-free concrete was poured. The results showed that with an increase in the fiber content, the thermal conductivity of the concrete samples decreases, the compressive and bending resistance increases at the age of (28) days, as well as, the density of concrete decreased. Besides, the results showed a slight improvement in the resistance to the impact of the slabs at the age of (90) days.