bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection of near-interface traps in NO annealed 4H-SiC metal oxide semiconductor capacitors combining different electrical characterization methods
Authors: Vidarsson Arnar M. , Nicholls Jordan R. , Haasmann Daniel , Dimitrijev Sima , Sveinbjörnsson Einar Ö.
Published: June 2022

Fast near-interface (NI) traps have recently been suggested to be the main cause for poor inversion channel mobility in nitrided SiC metal-oxide-semiconductor-field-effect-transistors. Combining capacitance, conductance, and thermal dielectric relaxation current (TDRC) analysis at low temperatures of nitrided SiC MOS capacitors, we observe two categories of fast and slow near-interface traps at the SiO2/4H-SiC interface. TDRC reveals a suppression of slow near-interface traps after nitridation. Capacitance and conductance analysis reveals a high density of fast NI traps close to the SiC conduction band edge that are enhanced by nitridation. The very fast response of NI traps prevents them from detection using TDRC or deep level transient spectroscopy.
Synthesis of La2−xSrxCuO4 films via atomic layer-by-layer molecular beam epitaxy
Authors: Xu Xiaotao , He Xi , Shi Xiaoyan , Božović Ivan
Published: June 2022

Atomic layer-by-layer molecular beam epitaxy (ALL-MBE) is a sophisticated technique to synthesize high-temperature superconductor (HTS) materials. ALL-MBE produces single-crystal HTS films with atomically smooth surfaces and interfaces, as well as precise multilayer heterostructures engineered down to a single atomic layer level. This enables the fabrication of tunnel junctions, nanowires, nanorings, and other HTS devices of interest. Our group has focused on ALL-MBE synthesis and materials science of La2−xSrxCuO4 (LSCO), a representative HTS cuprate. In the past two decades, we have synthesized over three thousand LSCO thin films and characterized them by a range of analytical techniques. Here, we present in full detail a systematic process for the synthesis and engineering of atomically perfect LSCO films. The procedure includes the preparation of substrates, calibration of the elemental sources, the recipe for ALL growth of LSCO films without any secondary-phase precipitates, post-growth annealing of the films, and ex situ film characterization. This report should aid replication and dissemination of this technique of synthesizing single-crystal LSCO films for basic research as well as for HTS electronic applications.
Mechanism of current-collapse free for lateral GaN Schottky barrier diodes utilizing polarization-induced hole injection
Authors: Zhang Tao , Li Ruohan , Zhang Yanni , Su Huake , Zhang Weihang , Duan Xiaoling , Zhang Jincheng , Xu Shengrui , Lv Yueguang , Hao Yue
Published: June 2022

In this Letter, a mechanism of current-collapse free for high-performance lateral AlGaN/GaN Schottky barrier diodes (SBDs) with a thick single-crystal GaN cap layer is investigated. A high breakdown voltage of 1.74 kV and a low specific on-resistance (RON,sp) of 5.04 mΩ cm2 are achieved for the fabricated SBD with a spatial distance (LAC) of 15 μm. Benefiting from the optimized groove anode technique, including a low-damaged etching process and a post-anode-annealing process, a low leakage current of 87 nA/mm at −500 V as well as a low turn-on voltage of 0.8 V defined at an anode current density of 1 mA/mm are obtained. Holes induced by polarization effects at the GaN/AlGaN interface inject to the anode edge at the ON state, and the negatively charged centers induced by a groove etching process are neutralized, which lead to the suppressed tunneling current (ITU) and idealized ideality factor (η). The forward current density decreases due to the suppressed ITU at the barrier-limited region. When the devices are biased at the OFF state, holes around cathodes inject to the buffer layer, which suppress hole emission at the buffer layer, and current collapse is greatly suppressed even after a 300-s-long bias test at −600 V.
40 GHz waveguide-integrated two-dimensional palladium diselenide photodetectors
Authors: Wang Yi , Zhou Yaoqiang , Zhang Zunyue , Xiao Shuqi , Xu Jian-bin , Tsang Hon Ki
Published: June 2022

Hybrid integration of two-dimensional (2D) materials with photonic integrated circuits can enable additional functionality in planar waveguides based on excellent optical and electrical properties of 2D materials. 2D layered palladium diselenide (PdSe2) has a narrow energy bandgap and high carrier mobility, and its stability under normal laboratory environment conditions makes it of interest for use as high-performance infrared photodetectors. In this work, we propose and experimentally demonstrate a high-speed waveguide-integrated photodetector which uses chemical vapor deposition grown PdSe2 transferred onto a silicon waveguide. At 1550 nm wavelength, the photodetector can be operated without external bias with a responsivity of 0.57 mA/W and a responsivity of 20 mA/W at 6 V bias voltage. The detector had an impulse response full-width-half-maximum pulse width of about 11 ps, corresponding to a 3-dB bandwidth of 40 GHz.
On native point defects in ZnSe
Authors: Wu Yifeng , Mirrielees Kelsey J. , Irving Douglas L.
Published: June 2022

Aiming at a fundamental understanding of the defect chemistry of pure ZnSe for optical and quantum applications, systematic density functional theory calculations with hybrid exchange-correlation functionals were performed to build an accurate database of native defects in ZnSe, including isolated defects and first nearest-neighbor defect–defect complexes. From the defect formation energies, zinc vacancy is found to be the most prevalent defect as the Fermi level approaches the conduction band edge, while zinc interstitial in the selenium tetrahedron and selenium vacancy become the most prevalent defects as the Fermi level approaches the valence band maximum. The divacancy complex, consisting of first nearest-neighboring zinc and selenium vacancies, is also found to have a favorable binding energy across the entire bandgap. Its formation energy is, however, always higher than either the isolated zinc or selenium vacancy, meaning it will never be the predominant defect in equilibrium. Finally, a point defect with extended spin coherence in Fluorine-implanted ZnSe was recently discovered, and it was found to exhibit a broad emission peak centered at 2.28 eV. The identity of this defect was determined to be either zinc vacancy or its associated complex according to the electron paramagnetic resonance measurements. Explicit simulations of the optical signatures of all zinc vacancy-related native defects were conducted here, showing that both zinc vacancy and divacancy are the most likely native defect contributors to that peak.
Understanding of glass-forming ability of Zr–Cu alloys from the perspective of vibrational entropy of crystalline phases
Authors: Kang Heng , Wang Ji , Zhang Yanhui , Li Zijing , Feng Shidong , Huo Juntao , Wang Li-Min
Published: June 2022

Glass formation is of fundamental importance for understanding the origin of glass transition and the design of new bulk metallic glasses. However, its nature has been extremely elusive and intangible over the past few decades. By combining experimental techniques and molecular dynamics simulations, we explored the mystery of glass-forming ability from the perspective of vibrational entropy in the prototypic Zr–Cu alloys. Our results suggest that the excess vibrational entropy of crystalline states and the low-frequency vibration modes can disclose the underlying physics behind good glass formers. The former works as an excellent indicator of glass formability to guide the more efficient composition design of novel glasses.
Laser cooling of Yb3+:LuLiF4 crystal below cryogenic temperature to 121 K
Authors: Lei Yongqing , Zhong Biao , Yang Tao , Duan Xuelu , Xia Meng , Wang Chaoyu , Xu Jiajin , Zhang Ziheng , Ding Jingxin , Yin Jianping
Published: June 2022

Optical cooling techniques of solid-state refrigerators, especially those toward the cryogenic temperature range, have attracted considerable attention in the fields of space exploration, precise measurement, material sciences, and so forth. Here, we report the laser cooling of the 7.5% Yb3+-doped LuLiF4 crystal down to 121 K reaching NIST's designated range of cryogenic temperatures (<123 K). Further results based on the cooling window indicate a promising cooling limit of 59 K, provided with enhancement in pump absorbance and heat load management of the sample. Our work, therefore, can motivate an all-solid-state optical refrigeration application beyond the liquid nitrogen boiling point, thus bringing great opportunity to realize cryogenic coolers and radiation-balanced lasers in miniaturized systems.
Electric-induced devil’s staircase in perovskite antiferroelectric
Authors: Hu Tengfei , Fu Zhengqian , Li Zhenqing , Yu Ziyi , Zhang Linlin , Yao Heliang , Zeng Kun , Wu Tiantian , Han Bing , Chen Xuefeng , Wang Genshui , Xu Fangfang
Published: June 2022

Antiferroelectric ceramics can realize ultra-high energy storage, which benefits from transformation between an antiferroelectric phase and a ferroelectric phase. Understanding the mechanism of such phase transition is the key point for building the structure-property correlation. Here, we report the observation of electric-induced devil’s staircase in the course of antiferroelectric–ferroelectric phase transition in PbZrO3-based antiferroelectric ceramics by in situ transmission electron microscopy. The dynamic evolution as-revealed in both reciprocal- and real-space involves stepwise rather than monotonic increase in modulation periods along with simultaneous proliferation of nanodomains. Desynchrony of phase transition is observed for incommensurate domains with different initial modulation periods within a single antiferroelectric domain. Then, the synergistic effect of the devil's staircase and as small as possible the initial modulation period is believed to contribute to the superior energy-storage performance. These findings will be helpful for the development of theories for antiferroelectric–ferroelectric phase transition and the design of high-power antiferroelectric materials.
High-temperature resonant ultrasound spectroscopy of highly radiation-damaged pyrochlore: Structural reorganization and high acoustic loss
Authors: Beirau Tobias , Carpenter Michael A.
Published: June 2022

High-temperature resonant ultrasound spectroscopy (HT-RUS) has been employed to follow in situ the thermally induced structural reorganization of highly radiation-damaged pyrochlore. The investigated sample with average composition (Na,Ca)2Nb2O6F contains ∼12 wt. % UO2 and has an amorphous fraction of ∼95%. The sample displays high acoustic loss, but an unconventional use of HT-RUS (monitoring the variation of the respective measured spectra's overall integrated intensity) nevertheless allows the thermally induced structural reorganization process to be followed in some detail. The recrystallization process is accompanied by clear changes in elastic properties, while initial heating causes elastic softening of the radiation-damaged pyrochlore. The results imply a general applicability of HT-RUS to in situ monitoring of the thermal behavior of highly attenuating materials.
Unsteady solute dispersion in non-Newtonian fluid flow in a tube with wall absorption—Deviation from the Gaussianity
Authors: Singh Shalini , Murthy P. V. S. N.
Published: June 2022

Unsteady solute dispersion in a pulsatile Herschel–Bulkley fluid flow in a tube is reinvestigated to examine the significance of the skewness and kurtosis on the concentration distribution using Aris' method of moments considering Hermite polynomials. This study is also an initiation in the direction of solute dispersion in a pulsatile non-Newtonian flow considering the first five moments. This investigation not only brings in the accuracy in the estimation but also measures the deflection and decrease in the axial mean concentration distribution of a solute in a tube. Significant variations in the skewness and kurtosis coefficients against various values of the flow governing parameters, such as the yield stress τy, the wall absorption parameter β, the power law index a, the Womersley frequency parameter α, and the amplitude of fluctuating pressure component e, are presented graphically along with the variations in the mean concentration distribution of the solute in the tube. For larger values of the Womersley frequency parameter, the occurrence of double frequency period for the convection and dispersion coefficients is noticed, which has significant influence on the skewness and kurtosis coefficients. The results for solute dispersion in Newtonian fluid, Bingham fluid, and power law fluid flows are also reported as special cases of this analysis.
Individual ion species chemical potentials in the Mean Spherical Approximation
Authors: Høye Johan S. , Gillespie Dirk
Published: June 2022

The Mean Spherical Approximation (MSA) is a commonly used thermodynamic theory for computing the energetics of ions in the primitive model (i.e., charged hard-sphere ions in a background dielectric). For the excess chemical potential, however, the early MSA formulations (which were widely adopted) only included the terms needed to compute the mean excess chemical potential (or the mean activity coefficient). Other terms for the chemical potential μi of individual species i were not included because they sum to 0 in the mean chemical potential. Here, we derive these terms to give a complete MSA formulation of the chemical potential. The result is a simple additive term for μi that we show is a qualitative improvement over the previous MSA version. In addition, our derivation shows that the MSA’s assumption of global charge neutrality is not strictly necessary, so that the MSA is also valid for systems close to neutrality.
A decade-long longitudinal survey shows that the Supreme Court is now much more conservative than the public
Authors: Jessee Stephen , Malhotra Neil , Sen Maya
Published: June 2022

Significance

Leveraging three unique surveys collected over a decade that ask members of the public about the policy issues before the US Supreme Court, we show how the court stands relative to the public. As we demonstrate, the court has, since 2020, become much more conservative than the public and is now more similar to Republicans in its ideological position on key issues. We also find that members of the public update their beliefs about the court’s ideology when its composition and rulings change. Even so, many members of the public currently underestimate the court’s conservative leaning, which in turn makes them less likely to support making changes to the institution than they would otherwise.
In situ structure of intestinal apical surface reveals nanobristles on microvilli
Authors: Zhu Hao , Li Meijing , Zhao Ruixue , Li Ming , Chai Yongping , Zhu Zhiwen , Yang Yihong , Li Wei , Xie Zhongyun , Li Xiaomin , Lei Kexin , Li Xueming , Ou Guangshuo
Published: June 2022

Significance

We study microvilli of
Caenorhabditis elegans
larvae and mouse intestinal tissues by combining high-pressure freezing, cryo-focused ion-beam milling, cryo-electron tomography, and subtomogram averaging. We find that many radial nanometer bristles, referred to as nanobristles, project from the lateral surface of nematode and mouse microvilli. The
C. elegans
nanobristles are 37.5 nm long. We show that nanobristle formation requires a protocadherin family protein, CDH-8, in
C. elegans
. The loss of nanobristles in cdh-8 mutants slows down animal growth and ectopically increases the number of Y-shaped microvilli, the putative intermediate structures if microvilli split from their tips. Our results reveal a potential role of nanobristles in separating microvilli and suggest that microvilli division may help generate nascent microvilli with uniformity.
Hemodynamic changes in prefrontal cortex following dynamic balance test in sporting and non-sporting population
Authors: Sathe Abhinav , Shenoy Shweta , Khandekar Sathe Prachi
Published: June 2022

Purpose

Balance is crucial for an individual's capacity to maintain an upright position during both static and dynamic conditions. Balance control is a complex sensory-motor action based on automated and spinal reflexes, under the influence of several distinct and separate supraspinal centres in the brainstem, cerebellum, and cortex. However, cortical neural activation during the functioning of sensory feedback mechanisms involved in the dynamic balance of the sporting group (SG) and non-sporting group (NSG) of young adults is yet to be evaluated. Thus, we evaluated hemodynamic changes in the prefrontal cortex (PFC) following a dynamic balance task in SG and NSG of young adults.

Materials and methods

The dynamic balance of 48 participants was evaluated using the wobble board of the Kinematics Measurement System. Hemodynamic changes were recorded using Functional Near Infra-red Spectroscopy System during the dynamic balance task.

Results

SG performed significantly better (p < .05) on the dynamic balance, as compared to the NSG. PFC hemodynamics was significantly different (p < .05) in SG and NSG.

Conclusion

We conclude that superior balance scores in SG compared to NSG are associated with different areas of activation of PFC during dynamic balance tasks.
MnO2–NiO–MWCNTs nanocomposite as a catalyst for methanol and ethanol electrooxidation
Authors: Shojaeifar Mohsen , Askari Mohammad Bagher , Hashemi Seyed Rouhollah Samareh , Di Bartolomeo Antonio
Published: June 2022

The potential of metal oxide-based nanocatalysts and multi-walled carbon nanotubes (MWCNTs) for the methanol and ethanol electrooxidation process is studied in the attempt of introducing cheap and stable nanocatalysts for use in the alcohol oxidation process. In this regard MnO2–NiO (MN), and MnO2–NiO–MWCNT (MNM) are synthesized and characterized in terms of structure and morphology. The electrocatalytic activity of these materials is evaluated by electrochemical tests. MNM show 90% cyclic stability after 1000 consecutive cycles in methanol oxidation reaction (MOR) and 86% in ethanol oxidation reaction (EOR) and maximum current densities of 262 and 148 μA cm−2 in methanol and ethanol electrooxidation, in optimal scan rate respectively. Also, the onset potential of MNM is lower than MN, indicating superior kinetics and facile oxidation of methanol due to the synergistic effect of adding MWCNTs to the structure of MN nanocatalyst. From these results, MNM can be an attractive and inexpensive option for use in MOR and EOR process for application in alcohol fuel cells.
Intermediate valence state in YbB4 revealed by resonant x-ray emission spectroscopy
Authors: Frontini Felix , Lebert Blair W , Cho K K , Song M S , Cho B K , Pollock Christopher J , Kim Young-June
Published: June 2022

We report the temperature dependence of the Yb valence in the geometrically frustrated compound

Y
b
B

4

from 12 to 300 K using resonant x-ray emission spectroscopy at the Yb

L

α
1

transition. We find that the Yb valence, v, is hybridized between the v = 2 and v = 3 valence states, increasing from

v
=
2.61
±
0.01

at 12 K to

v
=
2.67
±
0.01

at 300 K, confirming that

Y
b
B

4

is a Kondo system in the intermediate valence regime. This result indicates that the Kondo interaction in

Y
b
B

4

is substantial, and is likely to be the reason why

Y
b
B

4

does not order magnetically at low temperature, rather than this being an effect of geometric frustration. Furthermore, the zero-point valence of the system is extracted from our data and compared with other Kondo lattice systems. The zero-point valence seems to be weakly dependent on the Kondo temperature scale, but not on the valence change temperature scale T

v
.
A simulation of gas pipeline leakage monitoring based on distributed acoustic sensing
Authors: Fu Shichong , Zhang Dan , Peng Yang , Shi Bin , Yedili Nuerlan , Ma Zhuo
Published: June 2022

A simulation test on gas pipeline leakage by using distributed acoustic sensing technology was designed. An optical sensing cable with a spiral structure was adopted to improve the sensitivity of leakage monitoring. The method of pipeline leakage signal identification and location based on fast Fourier transform is proposed. By analyzing the vibration of the optical fiber in the time and frequency domains, the leakage signal can be accurately monitored. According to the variation in the spectral average amplitude of each sensing channel, the leakage point can be located, and the positioning equation is given. The size of the leakage hole and the direction of leakage on the spectral characteristics of the leakage signal are discussed. The average absolute amplitude in the time domain and spectral average amplitude in the frequency domain of the leakage signal decrease with the size of the leakage hole. As the angle between the leakage direction and the direction from the pipeline to the optical sensing cable increases, the spectral average amplitude of the leakage signal gradually decreases. The effect of the distance from the leakage hole on the leakage signal is discussed. The average absolute amplitude of the leakage signal decreases with the relative distance between the leakage hole and the optical sensing cable.
Quasi-aligned Cu2S/Cu(OH)2 nanorod arrays anchored on Cu foam as self-supported electrode for non-enzymatic glucose detection
Authors: Liao Yanxin , Du Qian , Sun Shupei , Shi Nianfeng , Yin Guangfu , Huang Zhongbing , Liao Xiaoming
Published: June 2022

Self-supported Cu2S/Cu(OH)2 composite nanorods for highly sensitive non-enzymatic glucose sensing were in situ grown on Cu foam by simple hydrothermal treatment of aligned Cu(OH)2 nanorods. The physicochemical and electrochemical properties of the as-fabricated Cu2S/Cu(OH)2 composite nanorods were characterized by scanning electron microscopy, transmission electron microscopy, x-ray diffraction, Raman spectroscope, x-ray photoelectron spectroscope, cyclic voltammetry, electrochemical impedance spectroscopy, amperometric i–t measurements. The mechanism of the composite nanorods produced on conductive substrates was also explored. The electrode exhibits a sensitivity of 9626.88 μA mM−1 cm−2 towards glucose with good anti-interference ability, indicating it a promising electrode material for the enhanced non-enzymatic glucose detection.
Real-time MRI motion estimation through an unsupervised k-space-driven deformable registration network (KS-RegNet)
Authors: Shao Hua-Chieh , Li Tian , Dohopolski Michael J , Wang Jing , Cai Jing , Tan Jun , Wang Kai , Zhang You
Published: June 2022

Purpose. Real-time three-dimensional (3D) magnetic resonance (MR) imaging is challenging because of slow MR signal acquisition, leading to highly under-sampled k-space data. Here, we proposed a deep learning-based, k-space-driven deformable registration network (KS-RegNet) for real-time 3D MR imaging. By incorporating prior information, KS-RegNet performs a deformable image registration between a fully-sampled prior image and on-board images acquired from highly-under-sampled k-space data, to generate high-quality on-board images for real-time motion tracking. Methods. KS-RegNet is an end-to-end, unsupervised network consisting of an input data generation block, a subsequent U-Net core block, and following operations to compute data fidelity and regularization losses. The input data involved a fully-sampled, complex-valued prior image, and the k-space data of an on-board, real-time MR image (MRI). From the k-space data, under-sampled real-time MRI was reconstructed by the data generation block to input into the U-Net core. In addition, to train the U-Net core to learn the under-sampling artifacts, the k-space data of the prior image was intentionally under-sampled using the same readout trajectory as the real-time MRI, and reconstructed to serve an additional input. The U-Net core predicted a deformation vector field that deforms the prior MRI to on-board real-time MRI. To avoid adverse effects of quantifying image similarity on the artifacts-ridden images, the data fidelity loss of deformation was evaluated directly in k-space. Results. Compared with Elastix and other deep learning network architectures, KS-RegNet demonstrated better and more stable performance. The average (±s.d.) DICE coefficients of KS-RegNet on a cardiac dataset for the 5- , 9- , and 13-spoke k-space acquisitions were 0.884 ± 0.025, 0.889 ± 0.024, and 0.894 ± 0.022, respectively; and the corresponding average (±s.d.) center-of-mass errors (COMEs) were 1.21 ± 1.09, 1.29 ± 1.22, and 1.01 ± 0.86 mm, respectively. KS-RegNet also provided the best performance on an abdominal dataset. Conclusion. KS-RegNet allows real-time MRI generation with sub-second latency. It enables potential real-time MR-guided soft tissue tracking, tumor localization, and radiotherapy plan adaptation.
Emergence of Sinai physics in the stochastic motion of passive and active particles
Authors: Shapira Dekel , Cohen Doron
Published: June 2022

A particle that is immersed in a uniform temperature bath performs Brownian diffusion, as discussed by Einstein. But Sinai has realized that in a ‘random environment’ the diffusion is suppressed. Follow-up works have pointed out that in the presence of bias f there are delocalization and sliding transitions, with threshold value f
c that depends on the disorder strength. We discuss in a critical way the emergence of Sinai physics for both passive and active Brownian particles. Tight-binding and Fokker–Planck versions of the model are addressed on equal footing. We assume that the transition rates between sites are enhanced either due to a driving mechanism or due to self-propulsion mechanism that are induced by an irradiation source. Consequently, counter intuitively, the dynamics becomes sub-diffusive and the relaxation modes become over-damped. For a finite system, spontaneous delocalization may arise, due to residual bias that is induced by the irradiation.
Reduced nonlocal integrable mKdV equations of type (−λ, λ) and their exact soliton solutions
Authors: Ma Wen-Xiu
Published: June 2022

Abstarct

We conduct two group reductions of the Ablowitz–Kaup–Newell–Segur matrix spectral problems to present a class of novel reduced nonlocal reverse-spacetime integrable modified Korteweg–de Vries equations. One reduction is local, replacing the spectral parameter with its negative and the other is nonlocal, replacing the spectral parameter with itself. Then by taking advantage of distribution of eigenvalues, we generate soliton solutions from the reflectionless Riemann–Hilbert problems, where eigenvalues could equal adjoint eigenvalues.
SOLPS-ITER modeling of CFETR advanced divertor with Ar and Ne seeding
Authors: Senichenkov I.Yu. , Ding R. , Molchanov P.A. , Kaveeva E.G. , Rozhansky V.A. , Voskoboynikov S.P. , Shtyrkhunov N.V. , Makarov S.O. , Si H. , Liu X. , Sang C. , Mao S. , Team CFETR
Published: June 2022

The Chinese Fusion Engineering Testing Reactor (CFETR) is a project proposed by the Chinese fusion community to bridge the gap between ITER and a commercial fusion power plant with fusion power up to 1 GW. The mitigation of divertor target heat fluxes for such a powerful machine is a challenging problem, which might appear to be more severe than in ITER. In the present paper, the results of the CFETR advanced divertor optimization by SOLPS-ITER modeling with full drifts and currents activated are presented. Three divertor geometries, which differ by the distance from the X-point to the strike point on the outer target, are considered. Argon (Ar) and neon (Ne) are compared as seeded impurities. It is demonstrated that for all three geometries and for both radiators it is possible to achieve acceptable divertor heat loads (below 5 MW m−2) without notable fuel dilution (Z
eff < 2.5). Impurity compression in divertors and pedestal radiation are compared for two gases. Similar core plasma and divertor conditions, as well as radiated power fraction, may be achieved with 2–3 times less Ar seeding rate than the Ne one. Estimated radiation from the confined region appears to be small compared to the exhaust power. However, in all modeling cases the T
e at the far scrape-off layer part of both targets remains significantly above 5 eV, which might cause tungsten (W) sputtering. Further optimization of target shape will be performed to reduce the electron and ion temperature.
Improvements of the on-the-fly MC variance reduction technique with dynamic WW upper bounds
Authors: Zheng Yu , Qiu Yuefeng , Lu Peng , Chen Yixue , Fischer Ulrich , Liu Songlin
Published: June 2022

This paper presents the recent progress in the development of the on-the-fly global variance reduction (OTF-GVR) method for Monte Carlo (MC) shielding calculations. OTF-GVR method provides on-the-fly weight window mesh (WWM) generation along with the particle transport simulation. In the previous study, the solution for the so-called ‘long-history’ problem, in which particles are unnecessarily over-split, is empirical and not fully effective. In this work, an innovative method using dynamic WWM upper bounds was proposed, which diminishes the over-splitting particles by relaxing the weight-windows upper bounds. This method has been proven effective through applications for several fusion reactors and neutron source facilities, with excellent performances over analogue simulations and variance reduction runs using common GVR methods.
Comparative Analysis and Development of Voice-based Chatbot System for Differently-abled
Authors: Jain Anjali , Bhati Pooja
Published: June 2022

One technology that improved humans’ lifestyle is a Chatbot System, an AI-based system that conducts people’s conversations. Chatbots are used in a wide range of applications-assistive technologies, customer service, home automation, education, medical bots, entertainment, etc. Such technology could be beneficial to differently-abled for teaching, assistance, etc. But when it comes to people with a slight speech disorder or autism, available chatbot systems aren’t very effective. This paper investigates the existing speech recognition APIs based on WER and CER and tries to improve results by adding a personalized layer for the user. This chatbot system can be embedded with existing technologies-domestic robots, smart mirrors, home automation, medical applications, etc. It will open these technologies to a wide range of audiences. The proposed Chatbot will use the existing speech recognition API and improve the results based on the above performance measures.
Survey: Tensorflow in Machine Learning
Authors: Ramchandani Monica , Khandare Hrishikesh , Singh Priyanshi , Rajak Prince , Suryawanshi Nidhi , Jangde Anjali Sagar , Arya Laxmi , Kumar Prithviraj , Sahu Mridu
Published: June 2022

TensorFlow(TF) is a large-scale ML system that can be used in many different situations. Data-flow graphs are used by TF to define operations, shared state, and computations that change that state. It distributes the nodes of a Data-flow graph across multiple machines in a cluster, as well as diverse processing units within a single system, such as multicore CPUs, general-purpose GPUs and Tensor Processing Units, which are custom-designed ASICs (TPUs). Developers may use TF to try out new training techniques and optimizations. It covers a broad applications range, which focus on inference and DNN training. It is utilised in production by several Google services, and it has since been released as an open-source project and is broadly used in ML research. We review TensorFlow and place it in the context of modern deep learning techniques and technologies in this paper. We go over the fundamental computational concepts and how they work. The distributed execution concept, as well as its programming interface as accompanying visualisation toolkit. The remainder of this paper will provide a comprehensive overview of TensorFlow and place it in the context of machine learning today
AI Model to Generate SQL Queries from Natural Language Instructions through Voice
Authors: Sawant Aditya , Raina Rohit , Patil Anuja , Pardeshi Anand
Published: June 2022

Data plays the most important role in the development of industries, small businesses. Even world leaders need the data to make analyses and make better policies for people. In almost every field where the work process is digitized need to store data and then retrieve it. According to statistics most of the data is stored in the relational database and for manipulations of the data, Structured Query Language(SQL) is commonly used. So for handling databases a person need to have specialized knowledge regarding the queries and had to remember the syntax of many complex queries. So to enhance data manipulation using SQL and to efficiently get the required query, the paper proposes a method for the generation of SQL query from natural language input, spoken(audio input) by the user. The model is constructed on NLP (Natural Language Processing) and Neural Networks (Deep Learning) technologies. Long Short Term Memory(LSTM) Model is used for predicting queries and is trained on the dataset with natural language as input and returns outline skeletal structure of the query as output. Then the output will be processed and the final query will be displayed to the user. The project also aims to benefit the people who are suffering from Repetitive Stress Injury (RSI), causing pain in the finger joints, which has been attributed to work requiring a long period of typing and also to those who are not familiar with SQL queries. As this system will readily provide the required query.
Delineation of groundwater potential zones in Safei watershed, Sundargarh, Odisha, using Remote Sensing and GIS techniques
Authors: Mohanty Swapnajit , Diwan P , Vishwakarma N. , Jhariya D C
Published: June 2022

Versatile use of groundwater made it more demanding and priceless. Rising inhabitants getting more dependent on groundwater and exploiting it rapidly. So we need to explore more groundwater potential zones for development and growth. This study done by unification of data files and maps such as satellite imagery, drainage, groundwater level, rainfall, land use land cover, slope, and existing maps of geology, in order to highlight groundwater prospect areas. Using overlay analysis tool safei watershed has been assigned weightage for the influencing factors. This study shows best suitable result for the groundwater prospecting. Today’s groundwater screenplay of town and commercial area of Safei watershed is considered as comestible for drinking purposes, handling. Additionally it is be in need of zones where groundwater found in excessive quantity for multifaceted application of human welfare.
Fabrication of UV-VIS photodetector based on the ZnO/MoS2 and ZnO/WS2 heterostructures
Authors: Winata Suci Mufidah , Fauzia Vivi
Published: June 2022

Two-dimensional layers of the transition metal dichalcogenides (2D TMDs) such as molybdenum disulfide (MoS2) and tungsten disulfide (WS2) attract much attention due to their potential applications in optoelectronic devices. MoS2 and WS2 with tunable bandgap are promising materials to enhance the light absorption range on ZnO-based photodetector. In this work, we report that the exfoliated MoS2 and WS2 were deposited on the surface ZnO nanorods for UV-vis photodetector application. The photoelectrical response of photodetector was observed using electrometer under 325, 505, and 625 nm laser diodes as UV and visible light sources. This study shows that the addition of MoS2 and WS2 could improve the performance of the ZnO photodetector due to higher photocurrent. The increase in both dark current and photocurrent is not yet clearly understood, but it may be that the edge sites of MoS2 and WS2 play a vital role to reduce the natural defects of ZnO; hence the mobility of charge carriers was improved.
Spectral characteristic of symmetric double tapered plastic optical fibers
Authors: Marinah M. , Puspita I. , Banurea D.P.M. , Zyrlirosa  , Hatta A.M. , Koentjoro Sekartedjo
Published: June 2022

Plastic optical fiber (POF) sensor has been immensely developed for many sensing applications including physical and chemical/bio sensor. Since it offers the advantages of non-destructive, easy fabrication and installation, immunity to electromagnetic interference, compact, low fabrication costs and higher durability compare to silica fiber sensor. Tapered POF is one of the modified structures on POF by reducing its diameter and induces guided modes in the core to be evanescent modes. As a sensor, the tapered structure on POF increase the sensitivity of non-tapered POF. The number of tapers on optical fiber affect its characteristics as well. Hence, it is important to investigate the characteristic of tapered POF with the variation on number of tapers. In this paper, the spectral characteristic of symmetric double tapered POF (DT POF) was investigated. The fabrication of symmetric DT POF was conducted by reducing the core diameter using chemical process as described in. The core diameter and the length of the tapered were fixed at 0.45 mm and 1 cm, respectively. The distance between two tapers was varied from 1-3 cm. Transmission spectrum characterization of symmetric DT POF was measured at near infrared wavelength range (900-1600 nm) using a spectrometer by OTO-Photonics.
Programmable photonic circuits
Authors: Marpaung David
Published: June 2022

We highlight a recent trend in photonics where integrated photonic chips are designed and operated as programmable devices like in the case of integrated electronics. We discuss the potential application of these programmable photonic circuits in signal processing.
Analysis of Aerodynamic Characteristics of High-speed Train with Asymmetric Heads
Authors: Li Weibin , Wang Yuejun , Hao Yunquan , Zhao Wei , Zhang Yanlin
Published: June 2022

High-speed transportation is closely related to people’s livelihood and national economy, so it becomes an important development aspect to the whole country. The safety, comfort and economy of high-speed train are the key consideration during its design process. In the future, new trains and old ones will be used for a long time, and the performance of new trains which run on the old lines may be limited. These situations make the research of high-speed train with asymmetric heads much necessary. Aiming at the feasibility of the train with asymmetric heads, the heads of train CRH3 and another typical train with a similar speed are selected. Based on the two heads, the digital models of the traditional trains with symmetric heads and the new trains with asymmetric heads are built firstly. And then their aerodynamic characteristics are computed by the SIMPLE method. In the numerical part, the performances of the trains are compared on the condition without crosswind, which shows that one of the new trains with asymmetric heads is the best among them. Moreover, the aerodynamic characteristics of this new model under crosswind is analyzed, which demonstrates that the train with asymmetric heads is feasible. The research shows that the train with asymmetric heads can achieve better results through the proper aerodynamic shape optimization design, which presents an idea for the future high-speed train design.
Numerical simulation on static aerodynamic characteristics of supersonic cavities
Authors: Luo Lei , Chen Hongyang , Zhang Jie , Jia Hongyin , Zhang Peihong
Published: June 2022

A numerical study on supersonic cavity flow is carried out, where the influence law of the freestream parameters and configuration factors on static aerodynamic characteristics is investigated, focusing on the change of pressure distribution on the cavity walls at high and low Mach numbers. It is found that with the Mach number increment at high speeds (M>2), the pressure peak on the rear side of the cavity bottom floor rises, and the change in pressure distribution on the cavity walls shows a variating trend in flow type from a closed-cavity flow to an open-cavity flow, which is consistent with the law at low speeds (M≤2). At high speeds, the change in Reynolds number has a certain impact on the pressure distribution in the cavity, which is inconsistent with the law at low speeds. The increase of Reynolds number will increase the pressure on the rear side of the cavity bottom floor and on the rear wall, and the greater the Mach number, the greater the difference caused by Reynolds number variation. When the length-to-depth ratio increases at high speeds, the pressure peak on the rear side of the cavity bottom floor decreases, and the flow type is changing from an open-cavity flow to a transitional-cavity flow, which is consistent with the law at low Mach numbers, while the pressure variation is greater at high speeds. The influence of the length-to-width ratio on the pressure distribution is relatively small, and the increase of length-to-width ratio increases the pressure peak on the rear side of the cavity bottom floor slightly. Spanwise bending has a certain impact on the pressure distribution. The pressure peak on rear side of the bottom floor increases when the cavity is bending, which is consistent with the influence caused by length-to-width ratio increment.
Simulation Research on the Effect of Reynolds Number on the Aerodynamic Characteristics of High Lift Device
Authors: Zhao Hui , Yang Yueyue , Zhang Yaobing , Li Weibin
Published: June 2022

Based on the consideration of grid factors and turbulence model factors, the confluence boundary layer and aerodynamic characteristics of the NHLP-2D airfoil are studied. Compared with the experimental results, the grid distribution near the confluence boundary layer is important for calculating the width of the wake area. The calculation results of the structured and unstructured grids are basically the same when the surface grid distribution is the same. On the basis of the mesh refinement in the wake area, the aerodynamic characteristics calculated by the SA turbulence model and the distribution of the total pressure coefficient in the confluence boundary layer are in good agreement with the experimental results. The width of the confluence boundary layer and the wake strength decrease with the increase of Reynolds number, the lift coefficient increases with the increase of Reynolds number, but the drag and pitching moment have opposite pattern. The maximum lift of the airfoil increases as the Reynolds number increases. As the Reynolds number increases, the stall angle of attack of the airfoil gradually increases and then remains stable with the increase of the Reynolds number.
Numerical analysis of horizontal bearing capacity of large-diameter implanted rock-socketed piles for offshore wind turbines
Authors: Wu Zhaoqi , Zhang Xingcheng , Song Qiming , Liu Wei , Chen Zhibing
Published: June 2022

There is no standard for rock-socketed pile foundation of offshore wind farm at China and abroad. According to the practical geological and environmental conditions of offshore wind power plant, response of rock-socketed pile under horizontal load was analyzed by using a finite element software, ABAQUS. Then, the parameters of rock-socketed pile, i.e. depth, pile diameter, ratio of pile diameter to thickness, and grouting thickness were investigated by orthogonal analysis and parametric analysis. It is found that the thickness of grouting has little influence on the displacement of pile head. The diameter and the ration of diameter to thickness of pile, rock-socketed depth have significant influence. The displacement of pile tip tends to stable and the bending moment at bottom of pile become zero when the rock-socketed depth reaches 3dp. The maximum Tresca stress of grouting body and 1st principal stress of rock mass decrease with an increase of rock-socketed depth.
Numerical Simulation of Orbit Controlled Hot-gas Lateral Jet of the triangular plate with rudder
Authors: Wan Zhao , Fu Yangaoxiao , Wang Xinguang , Chen Qi
Published: June 2022

Hypersonic interception weapons have high requirements for the efficiency and accuracy of the control system. As an effective control approach, the thermochemical non-equilibrium effect of jet flow must be considered in order to accurately predict the aerodynamic characteristic. At present, relevant researches are mostly focused on the low-flow rate hot jet, while numerical simulation and wind tunnel test studies on high-flow rate hot jet are rare. In this paper, the interaction flow field of the rail-controlled jet at the altitude of 60Km and 70Km has been simulated by solving the three-dimensional viscous fluid governing equations. The influence of the thermalchemical non-equilibrium effect of the jet interaction on the flow field characteristics and aerodynamic characteristics of the aircraft was analyzed. The primary results show that: (1) The flow fields of the cold-gas jet, frozen-gas jet and hot-gas jet have significant differences under the high-flow rate jet condition, which is mainly reflected the size and the pressure value of the separation region before the nozzle. The separation region length of the cold-gas jet is approximately twice that of the hot-gas jet and the length of the frozen-gas jet is between them; (2)Jet interaction will increase the surface pressure of the aircraft and reduce the skin-friction. When Ma=25, the aerodynamic interaction of hot jet is only about 30% of that of cold jet; (3) Jet interaction on aerodynamic characteristics increases with altitudes. With the increase of Mach number, the difference between the predicted results of hot jet and cold jet is enlarged because of the enhancement of the thermochemical non-equilibrium effect.
Experimental study of small-scale thin-layer boilover suppression using salt additive
Authors: Chen Miao , Wang Xuehui , Chen Qinpei , Wang Jian
Published: June 2022

The boilover is a well-known disaster for tank fires. Previous study has shown that changing the boiling point of sub-layer can suppress the small-scale thin-layer boilover, but the detail of suppression mechanism is not claimed. Thus, this study conducted experiments using salt additive with various initial fuel thickness (10mm, 15mm, 20mm). The boilover process and temperature characteristics in liquid pool is discussed. The thermal structure within the liquid pool is figure out in this paper, and the temperature evolution in burning process is analyzed. The results show that the salt additive can change the boiling point of sub-layer and the thermal structure within the liquid pool, which is the main mechanism to suppress the boilover.
Numerical Simulation of Robustness to Large Displacement of Optical Flow Based on Deep Learning
Authors: Wang Chao , Dong Xiucheng , Gu Shifu , Zhang Zhengyu
Published: June 2022

Traditional optical flow algorithm based on prior is sensitive to large displacement, in order to solve the problems, one optical flow algorithm based on deep learning is introduced to measure the global velocity of fluorescent oil film. The test results of numerical simulation show that the Average Endpoint Error (AEE) of HS, LK and Flownet2 are 2.4604 pixels, 2.3898 pixels and 0.9916 pixels in terms of warping 0.1s respectively, and the error of FlowNet2 is always the lowest under the conditions of large displacement. Therefore, the algorithm is more robust to large displacement than the others that is currently being used, which has certain exploration significance and engineering reference value.