bluuebunny/crossref_metadata_2025 huggingface dataset:
Homo-layer hafnia-based memristor with large analog switching window
Authors: Bai Na , Tian Baoyi , Mao Ge-Qi , Xue Kan-Hao , Wang Tao , Yuan Jun-Hui , Liu Xiaoxin , Li Zhaonan , Guo Shen , Zhou Zuopai , Liu Nian , Lu Hong , Tang Xiaodong , Sun Huajun , Miao Xiangshui
Published: January 2021

The fast development of high-accuracy neuromorphic computing requires stable analog memristors. While filamentary memory switching is very common in binary oxides, their resistive switching usually involves abrupt changes due to the rupture or reformation of metallic filaments. In this work, we designed a memristor consisting of dual-layer HfOy/HfOx, with different concentrations of oxygen vacancies (y > x). During the electroforming process, both the migration of existing oxygen vacancies in HfOx and the generation of new oxygen vacancies in HfOy occur simultaneously, leaving a semiconducting part close to the HfOy/HfOx interface. The resulting filament is not metallic as a whole, as revealed by first principles calculations. Such a device demonstrates excellent switching uniformity as well as highly gradual resistance change, ideal for neuromorphic computing. Through fine tuning of the filament structure, the device achieves low variation, high speed, gradual SET and RESET processes, and hundreds of stable multi-level state behaviors. The long-term synaptic plasticity was further achieved, showing good linearity and large analog switching window (ΔG as high as 487.5 μS). This works affords a route toward a gradual resistance change in oxide-based memristors.
Terahertz gyrotrons with inhomogeneous magnetic fields to suppress mode competition and enhance efficiency
Authors: Gao Zi-Chao , Du Chao-Hai , Li Fan-Hong , Liu Pu-Kun
Published: January 2021

Gyrotrons are promising radiation sources for bridging the terahertz gap. They are based on the instability of electron cyclotron maser, where the harmonic operation is generally necessary to alleviate the need for a strong magnetic field. Unfortunately, the performance of a harmonic gyrotron is extremely sensitive to mode competition and magnetic tuning. In this study, to achieve highly efficient and mode-selective gyrotrons, inhomogeneous magnetic fields are applied to introduce a specified longitudinal distribution of the detuning frequency between the terahertz wave and the gyrating electron beam. This detuning frequency has different influences on the oppositely traveling forward wave (FW) and backward wave (BW) inside the cavity, from which optimized magnetic-field profiles for FW-favored and BW-favored interaction circuits are generalized accordingly. It is proposed that a negatively tapering magnetic field converts the energy-transfer rate of the FW interaction into a positive value, leading to highly efficient FW interaction. By contrast, a positively tapering magnetic field reduces the detuning frequency of BW interaction and extends its effective length. By controlling the detuning frequency, a scenario of suppressed mode competition is proposed in a 330-GHz second-harmonic gyrotron. A universal understanding of the influence of an inhomogeneous magnetic field—i.e., the detuning frequency—on the interaction dynamics would help to develop efficient and broadband tunable terahertz gyrotrons.
Vapor condensation in Rayleigh–Bénard convection
Authors: Li Min , Zhang Yang , Liu Haihu , Wang Yuan , Yang Bin
Published: January 2021

In this work, the condensation process in the Rayleigh–Bénard convection is studied by a combination of theoretical analysis and numerical simulations. Depending on the domain size, three different patterns, namely, no condensation, critical condensation, and periodic condensation, are identified. By applying the order analysis to the energy equation, we show that the heat fluctuation is responsible to overcome the energy barrier of condensation and thus propose a new dimensionless number to describe the critical condition of condensation, which corresponds to zero value of the heat fluctuation. In addition, through the order analysis, a scaling law is established to quantify the condensation period when periodic condensation occurs. The scaling relations derived from the order analysis are well validated by the hybrid lattice Boltzmann finite difference simulations, where the Rayleigh number and the Prandtl number vary over the ranges of 104 ≤ Ra ≤ 106 and 1 ≤ Pr ≤ 10, respectively.
Oxygen vacancy induced phase and conductivity transition of epitaxial BaTiO3−δ films directly grown on Ge (001) without surface passivation
Authors: Dai Liyan , Niu Gang , Zhao Jinyan , Xue Yingxian , Luo Ren , Chen Bohan , An Ruihua , Sun Yanxiao , Feng Boyuan , Ding Sunan , Luo Wenbo , Ye Zuo-Guang , Ren Wei
Published: January 2021

The heterogeneous epitaxial system of BaTiO3/Ge (BTO/Ge) is of great interest for both fundamental research and device applications, thanks to its quasi-lattice-matching feature and the integration of functional oxides on semiconductors. Currently, the heteroepitaxial growth of crystalline BTO films on Ge includes the utilization of ultrahigh vacuum tools and complex surface passivation pre-treatment as well as careful control of oxygen partial pressure during the growth. Meanwhile, oxygen vacancies in oxides strongly impact their structural and electrical properties. Here, we report a facile method to directly grow single crystalline BTO films on Ge using pulsed laser deposition. The strict control of oxygen partial pressure ensures a sharp interface with an atom-to-atom registry and also leads to the oxygen-deficient characteristics of BTO. The epitaxial relationship of BTO and Ge is [110] BTO (001)//[100] Ge (001). Detailed crystallographic studies on BTO films with different thicknesses show that, for the films with a thickness less than 20 nm, BTO shows a mixture of tetragonal and cubic phases due to the oxygen vacancies and the strain from the Ge substrate and the cubic phase eventually dominates as the film thickness increases. Such oxygen-deficient BTO films reveal conducting characteristics rather than dielectric properties. The oxygen vacancies can be partly “cured” after a low temperature annealing process. These results not only demonstrate the possibility to directly grow single crystalline oxides on semiconductors without surface passivation but also highlight the importance of oxygen vacancies and lattice strain on the crystallographic and electrical properties of BTO films.
Global existence of strong solutions to MHD with density-depending viscosity and temperature-depending heat-conductivity in unbounded domains
Authors: Cao Yuebo , Peng Yi , Sun Ying
Published: January 2021

We study the equations of a planar magnetohydrodynamic (MHD) compressible flow with the viscosity depending on the specific volume of the gas and the heat conductivity being proportional to a positive power of the temperature. In particular, we obtain the global existence of the unique strong solutions to the Cauchy problem or the initial-boundary-value one under natural conditions on the initial data in one-dimensional unbounded domains. This result generalizes the classical one of the compressible Navier–Stokes system with constant viscosity and heat conductivity [Kazhikhov, Siberian. Math. J. 23, 44–49 (1982)] to the planar MHD compressible flow with nonlinear viscosity and degenerate heat-conductivity, which means no shock wave, vacuum, or mass or heat concentration will be developed in finite time, although the interaction between the magnetodynamic and hydrodynamic effects is complex and the motion of the flow has large oscillations.
Comparison of the double-photoionization processes in triphenylene and corannulene with coronene
Authors: Wehlitz Ralf , Hartman Tim , Huber David L.
Published: January 2021

We have studied the production of doubly charged molecular ions by a single photon for the aromatic molecules triphenylene (C18H12) and corannulene (C20H10) using monochromatized synchrotron radiation from 18 eV to 270 eV. We compare our results with previously published data for partially deuterated benzene (C6H3D3), pyrene (C16H10), and coronene (C24H12). The question that we address in this paper is how the different but similar molecular structures of coronene, corannulene, and triphenylene affect the photon-energy dependence of the ratio of doubly to singly charged parent ions. A theoretical analysis of the main features in terms of independent molecular subsystems will be discussed.
Thermal transport in superconducting niobium nitride: A first-principles study
Authors: Liu Zeyu , Luo Tengfei
Published: January 2021

Superconducting metallic transition-metal nitrides, especially from the family of NbNx, are promising in various applications. Due to the fact that the lattice constants and the crystal structures are similar to those of GaN, GaN/NbN heterostructures have been grown to combine the benefits of superconductors and semiconductors, where the thermal transport property is of great significance. In this Letter, the thermal transport property of metallic hexagonal NbN is studied using a first-principles approach with the consideration of both electron and phonon scatterings. It is interesting to find that unlike most metals, phonons play a bigger role in hexagonal NbN compared to electrons, due to a relatively small electron density of states near the Fermi level. At room temperature, our calculated thermal conductivity is close to the experimental data. Our findings can provide a deeper understanding of how heat is transported in metallic transition-metal nitrides and may help design semiconductor/superconductor heterostructures.
Community midwifery: a primary health care approach to care during pregnancy for Aboriginal and Torres Strait Islander women
Authors: Munns Ailsa
Published: January 2021

Comprehensive primary health care is integral to meaningful client-centred care, with nurses and midwives central to partnership approaches with individuals, families and communities. A primary health model of antenatal care is needed for Aboriginal and Torres Strait Islander women in rural and remote areas, where complex social determinants of health impact on pregnancy outcomes, early years and lifelong health. Staff experiences from a community midwifery-led antenatal program in a remote Western Australian setting were explored, with the aim of investigating program impacts from health service providers’ perspectives. Interviews with 19 providers, including community midwives, child health nurses, program managers, a liaison officer, doctors and community agency staff, examined elements comprising a culturally safe community antenatal program for Aboriginal and Torres Strait Islander women, exploring program benefits and challenges. Thematic analysis derived five themes: Organisational and Accessibility Factors; Culturally Appropriate Support; Staff Availability and Competencies; Collaboration; and Sustainability. The ability of program staff to work in culturally safe partnerships with clients in collaboration with community agencies was essential to building meaningful and sustainable antenatal strategies. Midwifery primary health care competencies were viewed as a strong enabling factor, with potential to reduce health disparities in accordance with Australian Government and research recommendations.
An Examination of Fitness to Stand Trial, Competence to Make Treatment Decisions, and Psychosis in a Canadian Sample
Authors: King Christopher M. , Del Pozzo Jill , Ceballo Dwight , Zapf Patricia A.
Published: January 2021

The purpose of this secondary analysis of an archival sample of 100 Canadian men remanded for evaluations of fitness to stand trial was to investigate the relationships among fitness, competence to make treatment decisions, and psychosis. As hypothesized, competence to make treatment decisions was more often impaired in those with impaired fitness. Among unfit defendants, a diagnosis of a psychotic disorder also related to impaired competence to make treatment decisions. The issue of competence to make treatment decisions may have utility for evaluations and restoration of fitness to stand trial and tending to it may help to alleviate systems burdens.
Loss of the K+ channel Kv2.1 greatly reduces outward dark current and causes ionic dysregulation and degeneration in rod photoreceptors
Authors: Fortenbach Christopher , Peinado Allina Gabriel , Shores Camilla M. , Karlen Sarah J. , Miller Eric B. , Bishop Hannah , Trimmer James S. , Burns Marie E. , Pugh Edward N.
Published: January 2021

Vertebrate retinal photoreceptors signal light by suppressing a circulating “dark current” that maintains their relative depolarization in the dark. This dark current is composed of an inward current through CNG channels and NCKX transporters in the outer segment that is balanced by outward current exiting principally from the inner segment. It has been hypothesized that Kv2.1 channels carry a predominant fraction of the outward current in rods. We examined this hypothesis by comparing whole cell, suction electrode, and electroretinographic recordings from Kv2.1 knockout (Kv2.1−/−) and wild-type (WT) mouse rods. Single cell recordings revealed flash responses with unusual kinetics, and reduced dark currents that were quantitatively consistent with the measured depolarization of the membrane resting potential in the dark. A two-compartment (outer and inner segment) physiological model based on known ionic mechanisms revealed that the abnormal Kv2.1−/− rod photoresponses arise principally from the voltage dependencies of the known conductances and the NCKX exchanger, and a highly elevated fraction of inward current carried by Ca2+ through CNG channels due to the aberrant depolarization. Kv2.1−/− rods had shorter outer segments than WT and dysmorphic mitochondria in their inner segments. Optical coherence tomography of knockout animals demonstrated a slow photoreceptor degeneration over a period of 6 mo. Overall, these findings reveal that Kv2.1 channels carry 70–80% of the non-NKX outward dark current of the mouse rod, and that the depolarization caused by the loss of Kv2.1 results in elevated Ca2+ influx through CNG channels and elevated free intracellular Ca2+, leading to progressive degeneration.
Optimization of the co-axial dispensing nozzle of a 3D bioprinter for the fabrication of tubular structures with micro-channel encapsulation
Authors: Xiong Shaoping , Chen Yang , Jia Wanbo , Yang Xuyang , Liu Kun , Li Chong , Ling Gang
Published: January 2021

The 3D bio-printing has been developed as an effective approach to artificially create tubular tissue structures, which have been frequently found in body and organ systems. China Agricultural University (CAU) has developed a laboratory 3D bio-printer that can create tubular structures with the encapsulation of microfluidic channel. In order to create a tubular structure with more effective micro-channel encapsulation for better nutrient delivery and chemical stimulation, this work presents a design optimization of co-axial dispensing nozzle of this 3D bio-printer. In this study, an experimentally validated two-phase flow computational fluid dynamics modeling tool based on ANSYS CFX has been developed to analyze the microfluidic domain of fluid channels inside the nozzle. The simulations on the extrusion and encapsulation process of bio-inks have been conducted. Based on the response surface method, the simulation work has established an equation to predict the volume fraction of the encapsulating layer against a variety of influencing factors including the size of extrusion nozzle, pneumatic pressure condition and the dynamic viscosity of the bio-ink. This equation has been used to recommend optimal solutions of printing parameters for the CAU bio-printer, which is expected to improve the quality of bio-printed tubular structure with an encapsulation.
Elastic electron scattering from chlorobenzene
Authors: da Mata V A S , Hlousek B A , Bardela F P , da Silva A J , Sakaamini A , Homem M G P , Khakoo M A
Published: January 2021

We report a joint theoretical–experimental investigation on elastic electron scattering by chlorobenzene in the low- and intermediate-energy ranges as a part of a collaborative project established between the Federal University of São Carlos (UFSCar) and the California State University (CSUF). More specifically, experimental elastic differential cross sections (DCS), in the incident electron energy range of 1.0 to 800 eV and scattering angle range of 10° to 130°, were measured using the crossed-beam relative-flow technique. Integral and momentum-transfer cross sections were determined from the numerical integration over the experimental DCS. Theoretically, elastic differential, integral, and momentum-transfer cross sections were calculated using a combination of a molecular complex optical potential model with the Padé approximant technique for impact energies ranging from 1.0 to 150 eV. Further calculations of DCS were performed at an energy range of 20 to 500 eV using the independent-atom model. Our results, which significantly extend available electron scattering cross sections for this target, are compared to existing theoretical and experimental data in the literature.
Photon-spin-dependent contribution to the

P,T

-odd Faraday rotation effect for atoms
Authors: Chekhovskoi S D , Chubukov D V , Skripnikov L V , Petrov A N , Labzowsky L N
Published: January 2021

The photon-spin-dependent (PS) contribution to the ordinary Faraday effect—optical rotation in an external magnetic field

H

⃗

is well known. This contribution is proportional to factor

(

s

⃗

p
h

⋅

H

⃗

)

where

s

⃗

p
h

is the photon spin. Recently a

P
,
T

-odd Faraday effect—optical rotation in an external electric field

E

⃗

—was discussed as a promising tool for observation of the electron electric dipole moment in the intra-cavity absorption spectroscopy. In the present paper, we introduce the PS contribution to the

P
,
T

-odd Faraday rotation effect. This contribution is proportional to

(

s

⃗

p
h

⋅

E

⃗

)

and has to be taken into account in the calculations of the

P
,
T

-odd Faraday effect.
Induced transparency based subwavelength acoustic demultiplexers
Authors: Gu Tianyu , Cheng Yi , Wen Zhihui , Ei Boudouti EI Houssaine , Jin Yabin , Li Yong , Djafari-Rouhani Bahram
Published: January 2021

Wave demultiplexers transporting desired wavelengths towards proper directions or ports are attracting numerous interests and applications in both physical and engineering areas. In acoustics, there is still a lack of compact and simple designs to achieve demultiplexers in three-port systems. In this work, we propose such a design using Helmholtz resonators where the frequency selection is based on the phenomenon of acoustically induced transparency (AIT). First, a modified transfer matrix method is derived to analytically describe and analyze the AIT effect with Helmholtz resonators. Then, the good performances of wave routing in these designs are further demonstrated by both simulation and experiment. These AIT based demultiplexers are subwavelength and simple in their designs. Therefore, they are promising for various potential applications such as signal processing, information communication and sensing.
Feasibility of lasing in the GaAs Reststrahlen band with HgTe multiple quantum well laser diodes
Authors: Afonenko Alexander , Ushakov Dmitrii , Alymov Georgy , Dubinov Aleksandr , Morozov Sergey , Gavrilenko Vladimir , Svintsov Dmitry
Published: January 2021

Operation of semiconductor lasers in the 20–50 µm wavelength range is hindered by strong non-radiative recombination in the interband laser diodes, and strong lattice absorption in GaAs-based quantum cascade structures. Here, we propose an electrically pumped laser diode based on multiple HgTe quantum wells with band structure engineered for Auger recombination suppression. Using a comprehensive model accounting for carrier drift and diffusion, electron and hole capture in quantum wells, Auger recombination, and heating effects, we show the feasibility of lasing at λ = 26, …, 30 µm at temperatures up to 90 K. The output power in the pulse can reach up to 8 mW for microsecond-duration pulses.
Effect of logarithmic perturbations in ohmic like spectral densities in dynamics of electronic excitation using variational polaron transformation approach
Authors: De Silva Nisal , Warnakula Tharindu , Gunapala Sarath D , Stockman Mark I , Premaratne Malin
Published: January 2021

Electronic excitation energy transfer is a ubiquitous process that has generated prime research interest since its discovery. Recently developed variational polaron transformation-based second-order master equation is capable of interpolating between Förster and Redfield limits with exceptional accuracy. Forms of spectral density functions studied so far through the variational approach provide theoretical support for various experiments. Recently introduced ohmic like spectral density function that can account for logarithmic perturbations provides generality and exposition to a unique and practical set of environments. In this paper, we exploit the energy transfer dynamics of a two-level system attached to an ohmic like spectral density function with logarithmic perturbations using a variational polaron transformed master equation. Our results demonstrate that even for a relatively large bath coupling strength, quantum coherence effects can be increased by introducing logarithmic perturbations of the order of one and two in super-ohmic environments. Moreover, for particular values of the ohmicity parameter, the effect of logarithmic perturbations is observed to be insignificant for the overall dynamics. In regard to ohmic environments, as logarithmic perturbations increase, damping characteristics of the coherent transient dynamics also increase in general. It is also shown that, having logarithmic perturbations of the order of one in an ohmic environment can result in a less efficient energy transfer for relatively larger system bath coupling strengths.
Insights into the hydrogen-bond cross-linking effects of small multiamine molecules on physical and mechanical properties of poly(vinly alcohol) by molecular dynamics simulations
Authors: Li Lujuan , Xu Xiaodong , Song Pingan , Cao Qianqian , Qiao Xin , Xu Zhiguang , Yang Yang , Zuo Chuncheng , Wang Hao
Published: January 2021

Small organic multiamine and multihydroxyl molecules have great potential for enhancing overall properties of poly(vinyl alcohol) (PVA) through the cross-linking effect of hydrogen bonds. However, experimentally there remains a remarkable lack of insightful understanding of the cross-linking effect on a molecular level. In the work, we report molecular dynamics simulations to reveal the cross-linking effect of hydrogen bonds of tetraaminopyrimidine (4N-2456) molecules on the structure, chain dynamics and mechanical properties of the PVA matrix. It was found that the addition of 4N-2456 leads to a nonlinear decrease of the free volume of PVA. A critical concentration of 4N-2456, about 5 wt%, was identified, resulting in the formation of 4N-2456 clusters. At this concentration, the PVA chains show the relatively slow mobility, the higher glass transition temperature and elastic modulus. Further increasing the 4N-2456 concentration enhances aggregation, and conversely weakens the interactions of hydrogen bonds between the PVA chains. Our work offers an understanding of how the 4N-2456 molecules influence the PVA chain dynamics and mechanical properties of the PVA matrix on molecular level.
Mechanically stable superhydrophobic nanostructured aluminum mesh with reduced water surface friction
Authors: Taghvaei Ehsan , Afzali Neda , Taghvaei Nastaran , Moosavi Ali
Published: January 2021

Superhydrophobic surfaces demonstrate significant characteristics which make them suitable for a wide variety of applications. In this study, we propose a facile, one-step, and cost-effective anodizing scheme using aluminum nitrate/stearic acid mixture solution to create a superhydrophobic surface on an aluminum mesh. The surface outperforms the surface anodized by the widely used oxalic acid solution in terms of superhydrophobicity and water-surface friction behavior. The proposed surface reduced the friction by 11% on average respective to the surface prepared by oxalic acid. The durability of the introduced superhydrophobic surface has also been investigated. The proposed surface retained its high water contact angle and showed higher hydrophobicity relative to the surface anodized by oxalic acid after ten abrasion cycles. This method and surface may be used for numerous applications due to its ease of fabrication, low cost, and excellent performance in energy-loss reduction.
Experience gravity in the classroom using the rubber sheet: an educational proposal from the collaboration between university and school
Authors: Postiglione Adriana , Angelis Ilaria De
Published: January 2021

Teaching modern physics in high school is of increasingly importance as it can offer students a more realistic and updated vision of the world, and can provide an opportunity to understand the most recent scientific discoveries. In this context, general relativity (GR) occupies a prominent place, since it is related to astonishing scientific results, such as the first image of a black hole or the discovery of gravitational waves. In this paper we describe an educational proposal aimed at teaching GR in high schools in a fun and playful way using the so-called rubber sheet analogy. We present a set of instructions to build a simple and low-cost space-time simulator, and a series of related educational cards that guide the teacher in the implementation of the activities step by step. This work is the result of a long and productive debate among Italian high school teachers who have collaborated for many years with the Department of Mathematics and Physics of Roma Tre University in Rome. As our proposal relies on the collaboration with the final users, we believe that it will meet their needs and expectations, and it will help to treat GR in high school more and more over time.
The cooling of a swede—part of an EUSO CSI challenge
Authors: Pendrill Ann-Marie
Published: January 2021

This paper presents preparations, execution and reflection on results for the physics part of a CSI task for the European Union Science Olympiad 2010, taking place at the University of Gothenburg. The participants were required to make a graph of the cooling of a swede (Brassica 
napus), as a proxy for the cooling of a murder victim, and to choose a mathematical expression for the cooling curve, as well as assigning an approximate time of death.
Physics of a hula hoop
Authors: Cross Rod
Published: January 2021

A hula hoop rotating around a person’s waist is an example of circular motion where the centripetal force on the hoop is directed towards the centre of the circle rather than the centre of the hoop. The friction force on the hoop is relatively small by comparison since the hoop rolls around the waist. A slight complication is that the hoop rotates in an elliptical path if the waist rotates back and forth in a straight line or if the waist rotates in an elliptical path. Three simple experiments are described to illustrate the physics involved.
Fast calculation of 3D radiofrequency ablation zone based on a closed-form solution of heat conduction equation fitted by ex vivo measurements
Authors: Chen Rendong , Zhang Jianfeng , Kong Dexing , Lou Qiong , Lu Fang
Published: January 2021

Fast calculation or simulation of the ablation zone induced by radiofrequency ablation (RFA) has a critical role in hepatic RFA planning and therapy. However, it remains challenging to approximate the ablation zone in real time, especially when more than one probe is involved in one ablation session. This paper presents a novel computational technique to calculate the 3D ablation zone of one probe RFA and two-probe switching RFA. The main idea is to get an approximate solution of the temperature distribution from a simplified Pennes bioheat equation, and further fit the solution to the coagulation measurements on ex vivo porcine liver. With a closed-form solution of temperature distribution, the calculation of the ablation zone is as simple as the commonly used ellipsoidal model, but it allows a more realistic prediction of combined ablation zones with different inter-probe spacing. The new approximation technique could potentially replace the original ellipsoidal model in the intervention planning step.
Predictive analysis for triton burnup ratio in HL-2A and HL-2M plasmas
Authors: Ogawa Kunihiro , Zhang Yipo , Zhang Jie , Sangaroon Siriyaporn , Isobe Mitsutaka , Liu Yi
Published: January 2021

The expected triton burnup ratio was analyzed based on numerical simulation to study the feasibility of demonstrating energetic particle confinement through 1 MeV triton burnup experiments in HL-2A and HL-2M. Calculations were conducted using LORBIT, a collisionless Lorentz orbit code, and FBURN, a neutron emission calculation code based on the classical confinement of energetic particles. First, the orbit loss and radial distribution of the tritons were evaluated using the LORBIT code. The LORBIT code revealed that all tritons were lost within ∼10−6 s in HL-2A, whereas in HL-2M, most of the tritons were still confined at 10−3 s. The FBURN code calculated the deuterium–tritium neutron emission rate using the radial distribution of 1 MeV tritons. The predictive analysis found that nearly no deuterium–tritium neutrons remained in HL-2A at a plasma current of 160 kA. Also, in HL-2M, a significant triton burnup ratio could be obtained at the relatively high plasma currents of 1MA, 2MA, and 3MA. This analysis predicts that the triton burnup ratio exceeds 1% under relatively high plasma current conditions.
Microdischarges properties in sDBD: the role of the exposed electrode oxidation
Authors: Selivonin I , Moralev I
Published: January 2021

The properties of microdischarges (MDs) in a surface barrier discharge, operating on various electrode materials are studied by current measurements and submicrosecond photography. Based on these data, the dynamics and statistics of MDs at various phases of the applied voltage are analyzed. It is shown that differences in oxide layer structure on the electrode edge strongly affect the spatial organization of the discharge and the properties of the current pulses.
Optical modeling of high-performance GaAs based photodetector with periodic right triangular texturization on nanopillar arrays structure
Authors: Baruah Smriti , Bora Joyatri , Maity Santanu
Published: January 2021

The high spectral responsivity of a photodetector depends upon proficient light absorption. In this respect, surface reflectance possesses a serious threat to the effective light absorption mechanism resulting in poor quantum efficiency. This paper presents an analytical investigation of a GaAs based periodic right triangular cut textured vertical nanopillar structural model deployed over a 50 μm × 50 μm planar front detector’s surface in reducing surface reflectivity. The geometrical analysis of the proposed model exhibits a 99.9% absorbance and 0.85 A W−1 photoresponsivity at 0.8 μm operating wavelength with a mere 0.5 μm depletion width.
The investigation of stability of n-CdS/p-Cu2S solar cells prepared by cold substrate method
Authors: Manir Melih , Nevruzoglu Vagif , Tomakin Murat
Published: January 2021

In this study, two different n-CdS/p-Cu2S solar cells were prepared by evaporating Cu at different substrate temperatures (200 K and 300 K) by vacuum evaporation method on a single crystal CdS semiconductor. Field emission scanning electron microscope images showed that the Cu layer obtained at a temperature of 200 K was composed of nanoparticles in accordance with the soliton growth mechanism. Cu film thickness was determined as 395 ∓ 0.76 nm at 300 K substrate temperature and 187 ∓ 0.45 nm at 200 K substrate temperature. The current–voltage (I–V) and capacitance–voltage (C–V) characteristics of the solar cells were examined for 12 weeks in dark and light environments. Open-circuit voltage (Voc), short-circuit current (Isc), maximum power (Pmax), filling factor and efficiency (η) were calculated fromI–Vmeasurements. For the prepared solar cells, the highest efficiency value was obtained in the 7th week (η= 0.1360) at 200 K substrate temperature, while it was obtained in the 5th week (η= 0.0384) at 300 K substrate temperature. FromC–Vmeasurements, donor density (Nd) and barrier potential (Vbi) were calculated. The solar cell produced at 200 K substrate temperature has higher donor density (1st week 2.99 × 1016cm−3) and barrier potential values (12th week 0.411 V). At the end of the 12-week period, the deterioration rate of solar cells created at 200 K and 300 K substrate temperatures was 51% and 94%, respectively.
Impurity dephasing in a Bose–Hubbard model
Authors: Caleffi Fabio , Capone Massimo , de Vega Inés , Recati Alessio
Published: January 2021

We study the dynamics of a two-level impurity embedded in a two-dimensional Bose–Hubbard (BH) model at zero temperature from an open quantum system perspective. Results for the decoherence across the whole phase diagram are presented, with a focus on the critical region close to the transition between superfluid and Mott insulator. In particular we show how the decoherence and the deviation from a Markovian behaviour are sensitive to whether the transition is crossed at commensurate or incommensurate densities. The role of the spectrum of the BH environment and its non-Gaussian statistics, beyond the standard independent boson model, is highlighted. Our analysis resorts on a recently developed method (2020 Phys. Rev. Res.
2 033276) – closely related to slave boson approaches – that enables us to capture the correlations across the whole phase diagram. This semi-analytical method provides us with a deep insight into the physics of the spin decoherence in the superfluid and Mott phases as well as close to the phase transitions.
A comparison of condensate mass of QCD vacuum between Wilson line approach and Schwinger effect *
Authors: Tahery Sara , Chen Xurong , Zou Liping
Published: January 2021

We studied the condensate mass of QCD vacuum through the duality approach via dilaton wall background in the presence of the parameter

, which represents the condensation in a holographic set up. First, from Wilson line calculation, we found

(i.e., the condensate parameter in mixed non-local condensation), whose behavior mimics that of QCD. The value of

that we found by this approach is in agreement with QCD data. Second, we considered the produced mass

via the Schwinger effect mechanism in the presence of the parameter

. We show that vacuum condensation generally contributes the mass dominantly and that the produced mass via Schwinger effect is suppressed by

.
Higgsino asymmetry and direct-detection constraints of light dark matter in the NMSSM with non-universal Higgs masses *
Authors: Wang Kun , Zhu Jingya , Jie Quanlin
Published: January 2021

In this study, we analyze the direct-detection constraints of light dark matter in the next-to minimal supersymmetric standard model (NMSSM) with non-universal Higgs masses (NUHM); we specially focus on the correlation between higgsino asymmetry and spin-dependent (SD) cross section. We draw the following conclusions. (i) The SD cross section is proportional to the square of higgsino asymmetry in dark matter

in the NMSSM-NUHM, and hence, it is small for highly singlino-dominated dark matter. (ii) The higgsino-mass parameter

is smaller than approximately

in the NMSSM-NUHM due to the current muon g-2 constraint, but our scenario with light dark matter can still be alive under current constraints including the direct detection of dark matter in the spin-dependent channel. (iii) With a sizeable higgsino component in the light dark matter, the higgsino asymmetry and SD cross section can also be sizeable, but dark matter relic density is always small; thus, it can escape the direct detections. (iv) Light dark matter in the

- and Z-funnel annihilation channels with sufficient relic density can be covered by future LUX-ZEPLIN (LZ) 7-ton in SD detections. (v) The spin-independent (SI) cross section is dominated by

- and

-exchanging channels, which can even cancel each other in some samples, leaving an SI cross section smaller by a few orders of magnitude than that of one individual channel.
Proton radioactivity half-lives with nuclear asymmetry factor
Authors: Soylu A. , Koyuncu F. , Gangopadhyay G. , Dehghani V. , Alavi S. A.
Published: January 2021

The dependence of proton emission half-lives on the nuclear asymmetry parameter is investigated using the WKB method and two types of empirical formula. Using the single-folding formalism with asymmetry-dependent nuclear radius and surface diffuseness of nuclear matter, the nuclear potential and consequently the half-life are functions of the asymmetry factor. Despite small values of asymmetry in neutron-deficient proton emitters, noticeable changes in the half-lives are observed. The addition of an asymmetry parameter term to the two forms of empirical formulas leads to a reduction in the rms error for ground state and isomeric transitions. A noticeable reduction of about 43% is obtained for isomeric transitions in the second form of the empirical formula. Considering ground state transitions in two categories, odd-even and odd-odd emitters, and adopting deformation and asymmetry-dependent empirical formulas, the rms decreases remarkably. The lowest values of rms errors, viz. 0.1492, 0.2312, and 0.1999, are obtained for the aforementioned empirical formulas for ground state transitions of odd-even and odd-odd emitters and for all isomeric transitions, respectively.
Prediction of electron density and pressure profile shapes on NSTX-U using neural networks
Authors: Boyer M.D. , Chadwick J.
Published: January 2021

A new model for prediction of electron density and pressure profile shapes on NSTX and NSTX-U has been developed using neural networks. The model has been trained and tested on measured profiles from experimental discharges during the first operational campaign of NSTX-U. By projecting profiles onto empirically derived basis functions, the model is able to efficiently and accurately reproduce profile shapes. In order to project the performance of the model to upcoming NSTX-U operations, a large database of profiles from the operation of NSTX is used to test performance as a function of available data. The rapid execution time of the model is well suited to the planned applications, including optimization during scenario development activities, and real-time plasma control. A potential application of the model to real-time profile estimation is demonstrated.
Comparison of SSA and SARIMA in Forecasting the Rainfall in Sumatera Barat
Authors: Fitri F , Rahmat R
Published: January 2021

Rainfall data in West Sumatra in 2001–2018 is assumed to have a seasonal pattern. Several methods can be used to model this data, including SSA and SARIMA. Each method has a different approach but has its own advantages. Therefore, a comparison will be made between the two based on the MAPE. According to the forecasting result, obtained MAPE for SSA is 17% and 22.75% for SARIMA.
Special Probability Distribution In Surah Al Falaq
Authors: Fitria D , Amalita N
Published: January 2021

Learn a subject which is not seem useful in daily life was really not interesting. How if it subject depends on religion, it will increase the motivation to study as worship spirit. All muslim known the Surah Al Falaq and they recite it daily since they were very young. In each verses in this surah tells us the concept of special probability distribution i.e Bernoulli, Binomial, Multinomial and Geometric distribution.
The Effectiveness of Student Worksheet Based on 4’Cs Skills to Improve Higher Order Thinking Skills Students’ SMP Pekanbaru
Authors: Yuanita P , Maimunah  , Arnellis
Published: January 2021

This study aims to determine the effectiveness of Student Worksheet (LKPD) based on 4'Cs skills and its effect on improving higher-order thinking skills of class VIII SMPN 4 Pekanbaru. The design used in this study was pre-experimental with the Static Group Comparison design. The data analysis technique was performed using statistical t-test. The results showed that this LKPD was declared effective as a learning innovation based on indicators of higher-order thinking skills. The effectiveness of the LKPD based on 4'Cs skills is proven to be influential in improving higher-order thinking skills based on the acquisition of results using the difference test.
Analysis of High Order Thinking Skill of Students in Contextual Problems Solving
Authors: Arnellis  , Fauzan A , Arnawa I M , Yerizon
Published: January 2021

This study aims to analyze the high-order thinking skills of students in solving contextual problems in calculus lectures. Currently, students are required to be more creative in solving calculus problems that lead to High Order Thinking Skill (HOTS) thinking, where students apply the knowledge and skills that have been developed during lectures in a new context. This type of research is qualitative, with a descriptive presentation method and a case study approach. The subjects in this study were six students of the January-June 2020/2021 semester mathematics education study program who were selected based on their level of ability to solve contextual questions. The data collection techniques used in this study were observation and written tests presented in contextual problems. Based on the research results, it can be concluded that student HOTS is determined by the student's ability to solve contextual questions, the higher the student's ability to solve contextual questions, the more HOTS indicators are achieved. HOTS students with high abilities are able to meet indicators of analyzing, evaluating, and creating. HOTS students with moderate ability are able to meet the indicators of analyzing and evaluating. HOTS students with low ability are able to only meet the analyzing indicators, The results showed that there were differences in HOT problem solving among students with high, medium and low abilities.
An Initial Observation for Development of Learning Instruction Based on Ethnomathematic at SMP Pembangunan Padang
Authors: Rurisman  , Yerizon
Published: January 2021

Junior high school student learning outcomes are still low, especially problem solving abilities. This happens because the existing equipment does not match the characteristics of students. Good learning instruction will lead students to have good problemsolving abilities. Initial observations aim to find, analyze and explain (1) students' mathematical problem solving abilities (2) the conditions of learning tools (LKPD) used and developed by the teacher (3) as a basis for continuing ethnomatematic based development research to develop problem solving abilitiesof students. This is a descriptive study research with a qualitative approach. The results of the observations made at the UNP Laboratory Development Junior High School, it can be concluded that the learning tools still not connect the material with the environment and student culture, so the learning experienced by students is less meaningful. The LKPD used are still general and does not match the characteristics of students.
Development of Problem-Based Learning (PBL) Instrument to Improve Mathematical Communication
Authors: Putri M E , Yerizon  , Khaidir C
Published: January 2021

The purpose of the research is to develop students' worksheet with valid, practical, and effective PBL-based for the second semester of VIII grade students of SMP / MTs to improve mathematical communication. This research was conducted in class VIII of MTsN 7 Tanah Datar. This research was using Plomp model development, which consists of three phases, namely preliminary research, prototyping, and assessment. The instruments used in this research were LKPD validation sheets, questionnaires, interview guidelines, and tests. Before using the tool to collect data, the tool has been validated by the validator. The results showed that the designed LKPD is valid, practical, and effective.
Application of the E-Learning with Adaptive Theory Information Model in English for Mathematics Lectures
Authors: Jamaan E Z , Arnellis
Published: January 2021

After the emergence of the Covid-19 outbreak, the education system began to look for the latest innovations to form an effective lecture process with a learning model that was suitable for students in distance learning using the E-Learning learning model which was been adaptive additional information was needed. It;s known as the Elita model. The purpose of this research is to produce profile information about Elita's users who are categorized, in student's achievement and student's preferences in English for Mathematics lectures. This type of research is a mixture of qualitative and quantitative. Quantitative data were obtained from tests, and qualitative data were obtained from interviews and observations. The population is students of Mathematics Education, Universitas Negeri Padang. The sample was 43 students from January to June 2020 semesters. The instruments used were interview guides, field notes, and tests. The results obtained were the achievement of student's achievement in understanding the EFM lecture material, an increase in the average score, while the results of student’s preference in the EFM lecture process with the Elita model was moderate.
Development of an Android-Based for Math E-Module by using Adobe Flash Professional CS6 for Grade X Students of Senior High School
Authors: Ilmi R , Arnawa I M , Yerizon  , Bakar N N
Published: January 2021

Learning in the industrial revolution 4.0 requires the optimal use of technology in the learning, one of which is by learning to use mathematical e-modules that can be operated on smartphones using an android operating system. This study aimed to create valid, practical, and effective android-based e-modules. This research was research and development (R&D) with the Plomp development model, which consists of the preliminary research phase, the development or prototyping phase, and the assessment phase. The subjects of this study were students of grade X in SMA N 5 Pekanbaru. The results of this study were the android-based e-module was valid, practical, and effective. The validity of e-modules was classified based on the results of the experts' evaluation. The practicality of the e-module was classified based on the questionnaire responses of teachers and students, who can use the e-module well, can help students in understanding the material, and interested in using it. The effectiveness of e-modules was classified by the percentage of student's completeness learning after using e-modules more than 70%.