bluuebunny/crossref_metadata_2025 huggingface dataset:
Feature extraction method of HPLC communication signal based on genetic algorithm
Authors: Tang Chao , Chang Zhengwei , Liang Huihui , Zhang Linghao , Pang Bo
Published: June 2023

Communication quality is a key factor affecting the effectiveness of distribution network operation status management. Therefore, it is required that the communication performance of the distribution network management system be good, and the communication signal can directly reflect the communication quality. Therefore, a genetic algorithm (GA) based HPLC communication signal feature extraction method is proposed. The process of constructing reference samples, training recognition models, constructing noise samples, self‐coding denoising processing, and denoising sample recognition has completed the identification of power line channel transmission characteristics. The state feature quantity of the topological line is based on the positioning results of the diagnostic function, and the calculated value of the reflection coefficient calculation model at the head end of the topological line is compared with the measured value. By optimizing the feature quantities containing topological line states through GAs, abnormal feature quantities close to the true state of topological lines are obtained. Experimental analysis shows that this method can correctly identify the position of reactive power compensation in the transmission line, and can also correctly identify the extraction of topological anomaly features. Therefore, the research method is of great significance in improving the safe operation of power systems and extending the service life of topology lines.
A digital delay locked loop with a monotonic delay line
Authors: Liu Jen‐Chieh , Yang Chuan
Published: June 2023

This paper proposes a digital delay locked loop (DLL) with a monotonic delay line (DL). This DLL adopts the calibration mode to reduce the non‐monotonic effects for the coarse‐tuning delay line (CTDL) and the fine‐tuning delay line (FTDL). The calibration mode detects the delay time of the delay unit, the timing resolution of CTDL, to adjust the delay range of the FTDL. Thus, the calibration mode can limit the overlap range of the delay time between the CTDL and the FTDL. The proposed DLL was implemented using a 0.18‐μm CMOS process, and the RMS and the peak‐to‐peak jitters of the DLL were 0.21% and 1.72%, respectively, at 560 MHz.
Computational social science in smart power systems: Reliability, resilience, and restoration
Authors: Valinejad Jaber , Mili Lamine , Yu Xinghuo , van der Wal C. Natalie , Xu Yijun
Published: June 2023

Smart grids are typically modelled as cyber–physical power systems, with limited consideration given to the social aspects. Specifically, traditional power system studies tend to overlook the behaviour of stakeholders, such as end‐users. However, the impact of end‐users and their behaviour on power system operation and response to disturbances is significant, particularly with respect to demand response and distributed energy resources. Therefore, it is essential to plan and operate smart grids by taking into account both the technical and social aspects, given the crucial role of active and passive end‐users, as well as the intermittency of renewable energy sources. In order to optimize system efficiency, reliability, and resilience, it is important to consider the level of cooperation, flexibility, and other social features of various stakeholders, including consumers, prosumers, and microgrids. This article aims to address the gaps and challenges associated with modelling social behaviour in power systems, as well as the human‐centred approach for future development and validation of socio‐technical power system models. As the cyber–physical–social system of energy emerges as an important topic, it is imperative to adopt a human‐centred approach in this domain. Considering the significance of computational social science for power system applications, this article proposes a list of research topics that must be addressed to improve the reliability and resilience of power systems in terms of both operation and planning. Solving these problems could have far‐reaching implications for power systems, energy markets, community usage, and energy strategies.
Investigation and 3E (economic, environmental and energy) analysis of a combined heat and power system based on renewable energies for supply energy of sport facilities
Authors: Fei Jiaming , Su Zhanguo , Yao Yuzhong , Fei Cheng , Shamel Ali
Published: June 2023

Due to the regular reduction of fossil fuels and the increase in emissions as a result of fossil fuel consumption, the use of renewable energy‐based systems is increasing gradually and microgrid systems have developed significantly due to the simultaneous production of electricity and heat on a very large scale. Therefore, microgrid modelling has been done considering fossil and non‐fossil sources wind turbines and photovoltaic cells are considered the main sources of energy supply and a gas turbine is the supporting source that thermal energy production in the system is the responsibility of the boiler. The purpose of the system modelling is optimization by considering different conditions including maximum energy supply, reducing emissions, and reducing the cost of operation, which is why different scenarios were evaluated. For an accurate evaluation, different scenarios have been set for the production of energy from different sources. One of the important results is the lower cost of the first scenario compared to the other two scenarios, the total cost of which is $180.53. In this scenario, 72.2466 kWh of electricity is purchased and 43.62 kWh of electricity is sold.
Parking space number detection with multi‐branch convolution attention
Authors: Guo Yifan , Zhang Jianxun , Lin Yuting , Zhang Jie , Li Bowen
Published: June 2023

With the increase of large shopping malls, there are many large parking spaces in complex environments, which increases the difficulty of finding vehicles in such environments. To upgrade the consumer's experience, some car manufacturers have proposed detecting parking space numbers in parking spaces. The detection of parking space number in parking spaces in complex environments has problems such as the diversified background of parking space numbers, tilted direction of parking space numbers, and small parking space number scale. Since no scholar has proposed a high‐performance method for such problems, a parking space number detection model based on the multi‐branch convolutional attention is presented. Firstly, using ResNet50 as the backbone network, a multi‐branch convolutional structure is proposed in the backbone network, which aims to process and fuse the feature map through three parallel branches, and enhance the network to represent ability information by convolutional attention, learn global features to selectively strengthen the features containing helpful information, and improve the ability of the model to detect the parking space number area. Secondly, a high‐level feature enhancement unit is designed to adjust the features channel by channel, obtain more spatial correlation, and reduce the loss of information in the process of feature map generation. The data results of the model on the parking space number dataset CCAG show that the precision, recall, and F‐measure are 84.8%, 84.6%, and 84.7%, respectively, which has certain advantages for parking space number detection.
Long-term optical spectral monitoring of a changing-look active galactic nucleus NGC 3516
Authors: Popović Luka Č. , Ilić Dragana , Burenkov Alexander , Patiño Alvarez Victor Manuel , Marčeta-Mandić Sladjana , Kovačević-Dojčinović Jelena , Shablovinskaya Elena , Kovačević Andjelka B. , Marziani Paola , Chavushyan Vahram , Wang Jian-Min , Li Yan-Rong , Mediavilla Evencio G.
Published: June 2023

Context.We analyze the broad Hβline profile variability of a “changing look” active galactic nucleus (CL-AGN) NGC 3516 over an extensive period of 25 years (from 1996 to 2021). The observed change in the broad line profile may indicate a change in the geometry of the broad line region (BLR). The main objective is to follow and understand the change in the BLR over a long period as well as its connection to the CL mechanism.

Aims.Using spectral line profiles, we aim to explore changes in the kinematics and dimensions of the BLR in NGC 3516. We consider two possible scenarios: the changes in the broad-line emission are either caused by a decrease of ionisation continuum emission or by the BLR obscuration by outer dusty regions. With this investigation, we aim to clarify the CL mechanism of this AGN.

Methods.We analyzed the spectral band around the Hβline as well as the broad Hβline parameters and how they change over time. We modelled the broad-line profiles, assuming that there is an emission from the accretion disc superposed with emission from a surrounding region that is outside the disc.

Results.We find that in the type 1 activity phase occurring when the strong broad emission lines are observed, the BLR is very complex. There is a clear disc-like BLR that contributes to the broad line wings and an additional intermediate line region (ILR) that contributes to the line core. In the high-activity phase, the ILR emission is close to the center of the line, although in some cases, it is slightly shifted to the red. In the low-activity phase (i.e. type 2 phase), the ILR component has a significant shift to the blue, indicating an outflow.

Conclusions.We propose that the changing-look mechanism in NGC 3516 is rather connected with the intrinsic effects than with an outer obscuring region. It may still be possible that the dust plays an important role in the low-activity phase when it is coming from within the BLR, leading to a dusty BLR. In this way, it would cause a decrease in the ionisation and recombination rates.
A z = 1.85 galaxy group in CEERS: Evolved, dustless, massive intra-halo light and a brightest group galaxy in the making
Authors: Coogan Rosemary T. , Daddi Emanuele , Le Bail Aurélien , Elbaz David , Dickinson Mark , Giavalisco Mauro , Gómez-Guijarro Carlos , de la Vega Alexander , Bagley Micaela , Finkelstein Steven L. , Franco Maximilien , Cooray Asantha R. , Behroozi Peter , Bisigello Laura , Casey Caitlin M. , Ciesla Laure , Dimauro Paola , Finoguenov Alexis , Koekemoer Anton M. , Lucas Ray A. , Pérez-González Pablo G. , Yung L. Y. Aaron , Arrabal Haro Pablo , Kartaltepe Jeyhan S. , Jogee Shardha , Papovich Casey , Pirzkal Nor , Wilkins Stephen M.
Published: June 2023

We present CEERS JWST/NIRCam imaging of a massive galaxy group at z = 1.85, to explore the early JWST view on massive group formation in the distant Universe. The group contains ≳16 members (including six spectroscopic confirmations) down to log10(M⋆/M⊙) = 8.5, including the brightest group galaxy (BGG) in the process of actively assembling at this redshift. The BGG is comprised of multiple merging components extending ∼3.6″ (30 kpc) across the sky. The BGG contributes 69% of the group’s total galactic stellar mass, with one of the merging components containing 76% of the total mass of the BGG and a star formation rate > 1810 M⊙ yr−1. Most importantly, we detected intra-halo light (IHL) in several HST and JWST/NIRCam bands, allowing us to construct a state-of-the-art rest-frame UV-NIR spectral energy distribution of the IHL for the first time at this high redshift. This allows stellar population characterisation of both the IHL and member galaxies, as well as the morphology distribution of group galaxies versus their star formation activity when coupled with Herschel data. We created a stacked image of the IHL, giving us a sensitivity to extended emission of 28.5 mag arcsec−2 at rest-frame 1 μm. We find that the IHL is extremely dust poor (Av ∼ 0), containing an evolved stellar population of log10(t50/yr) = 8.8, corresponding to a formation epoch for 50% of the stellar material 0.63 Gyr before z = 1.85. There is no evidence of ongoing star formation in the IHL. The IHL in this group at z = 1.85 contributes ∼10% of the total stellar mass, comparable with what is observed in local clusters. This suggests that the evolution of the IHL fraction is more self-similar with redshift than predicted by some models, challenging our understanding of IHL formation during the assembly of high-redshift clusters. JWST is unveiling a new side of group formation at this redshift, which will evolve into Virgo-like structures in the local Universe.
Hilfe Bei Exoten – Künstliche Intelligenz bei Seltenen Erkrankungen
Authors: Schwencke Silja
Published: June 2023

Von rund 30 000 bekannten Krankheiten zählen 6000 bis 8000 zu den seltenen. Bis ihre Krankheit erkannt wird, machen die Patient*innen oft eine Odyssee mit. Wichtige Gründe dafür sind mangelndes Wissen und Bewusstsein für Seltene Erkrankungen. Der Einsatz künstlicher Intelligenz könnte dies ändern.
Patient-Reported Outcomes Measures in Rhinoplasty: Need for Use and Implementation
Authors: Warinner Chloe , Loyo Myriam , Gu Jeffrey , Wamkpah Nneoma S. , Chi John J. , Lindsay Robin W.
Published: June 2023

Patient-reported outcome metrics (PROMs) are increasingly utilized to capture data about patients' quality of life. PROMs play an important role in the value-based health care movement by providing a patient-centered metric of quality. There are many barriers to the implementation of PROMs, and widespread adoption requires buy-in from numerous stakeholders including patients, clinicians, institutions, and payers. Several validated PROMs have been utilized by facial plastic surgeons to measure both functional and aesthetic outcomes among rhinoplasty patients. These PROMs can help clinicians and rhinoplasty patients participate in shared decision making (SDM), a process via which clinicians and patients arrive at treatment decisions together through a patient-centered approach. However, widespread adoption of PROMs and SDM has not yet been achieved. Further work should focus on overcoming barriers to implementation and engaging key stakeholders to increase the utilization of PROMs in rhinoplasty.
What motivates business to donate to politics? A framework and an empirical application
Authors: McMenamin Iain , Power Sam
Published: June 2023

The secrecy, subtlety, and diversity of party-firm relations have proven challenging to synthesize. We introduce a new heuristic framework for the study business donors on the basis of pragmatic, partisan, and social motivations. We illustrate our framework with an analysis of donors to the UK Conservative Party from the property services and construction industries. While actors make it almost impossible to place particular events in our framework, in the aggregate the framework is empirically tractable. We triangulate a study of over twenty years of donations data, news on social events, and qualitative data to argue that the construction industry is motivated by a combination of pragmatic and social motivations, while the property services industry is best described by a combination of the social and partisan motivations.
Emotion classification for short texts: an improved multi-label method
Authors: Liu Xuan , Shi Tianyi , Zhou Guohui , Liu Mingzhe , Yin Zhengtong , Yin Lirong , Zheng Wenfeng
Published: June 2023

The process of computationally identifying and categorizing opinions expressed in a piece of text is of great importance to support better understanding and services to online users in the digital environment. However, accurate and fast multi-label automatic classification is still insufficient. By considering not only individual in-sentence features but also the features in the adjacent sentences and the full text of the tweet, this study adjusted the Multi-label K-Nearest Neighbors (MLkNN) classifier to allow iterative corrections of the multi-label emotion classification. It applies the new method to improve both the accuracy and speed of emotion classification for short texts on Twitter. By carrying out three groups of experiments on the Twitter corpus, this study compares the performance of the base classifier of MLkNN, the sample-based MLkNN (S-MLkNN), and the label-based MLkNN (L-MLkNN). The results show that the improved MLkNN algorithm can effectively improve the accuracy of emotion classification of short texts, especially when the value of K in the MLkNN base classifier is 8, and the value of α is 0.7, and the improved L-MLkNN algorithm outperforms the other methods in the overall performance and the recall rate reaches 0.8019. This study attempts to obtain an efficient classifier with smaller training samples and lower training costs for sentiment analysis. It is suggested that future studies should pay more attention to balancing the efficiency of the model with smaller training sample sizes and the completeness of the model to cover various scenarios.
Current collapse suppression in AlGaN/GaN HEMTs using dual-layer SiNx stressor passivation
Authors: Deng Chenkai , Cheng Wei-Chih , Chen XiGuang , Wen KangYao , He MingHao , Tang ChuYing , Wang Peiran , Wang Qing , Yu HongYu
Published: June 2023

In this work, a dramatic reduction in current collapse is achieved in GaN-based high-electron-mobility transistors (HEMTs) using dual-layer SiNx stressor passivation (DSSP), and the related mechanism is proposed. The SiNx compression neutralizes the inherent piezo polarization caused by the lattice mismatch at the heterojunction and effectively mitigates the peak electric field crowding at the drain-side gate edge, as supported by technology computer-aided design simulation. Thus, the inverse piezoelectric effect is suppressed and the trapped charge density is reduced under high electrical stress. As a result, the current collapse effect can be significantly restrained. Upon pulsing (Vg = −6 and Vds = 20 V), the device with DSSP exhibits a negligible current collapse (∼3%), which is significantly lower than the baseline device (∼34%). Moreover, it shows a one-order-of-magnitude reduction in gate leakage and a significant enhancement in gate stability. These results prove that the DSSP process is an attractive technique to facilitate high-reliability GaN-on-Si HEMTs.
A method for high-precision measuring differential transformer asymmetry
Authors: Yang Xiao-Tian , Hu Ming , Wang Cheng-Rui , Li Duo , Chen De-Cong , Ouyang Chao-Li , Bai Yan-Zheng , Qu Shao-Bo , Zhou Ze-Bing
Published: June 2023

The differential transformer is an important component in the front-end electronics of high-precision capacitive position sensing circuits, which are widely employed in space inertial sensors and electrostatic accelerometers. The position sensing offset, one of the space inertial sensors’ most critical error sources in the performance range, is dominated by the differential transformer asymmetry and requires a high-precision evaluation. This paper proposes a method to assess differential transformers’ asymmetry and realize a prototype circuit to test a transformer sample. The results show that the asymmetry measurement precision can achieve 0.6 ppm for the transformer with an asymmetry level of about −278.2 ppm.
A quartz crystal microbalance (QCM)-based easy setup device for real-time mass change detection under high-power RF plasma
Authors: Senturk Fatih , Kocum Ismail Cengiz , Seyitoglu Melek Ilayda , Aksan Eda Sevval
Published: June 2023

Sensing technologies serve a crucial role in monitoring and testing surface properties in biosensors, thin films, and many other industries. Plasma treatments are routinely used in most of these technologies to modify the surfaces of materials. However, due to the high radio frequency (RF) noise in plasma processes, real-time surface tracking is still rather difficult. In this study, we aim to construct an easy-to-set up mass change detection system capable of operating under RF plasma conditions. For this purpose, we have presented a novel technique that utilizes the quartz crystal microbalance sensor to detect mass changes in different plasma environments. The constructed device was then tested under 13.56 MHz, 100 W plasma atmosphere. The results showed that the resonance frequency of a crystal was successfully measured with 1.0 Hz resolution under the impact of plasma-induced high power of RF noise. Moreover, as a preliminary study, we used ethylenediamine (EDA) to track changes in resonance frequency under plasma conditions and observed noise-free signals in frequency–voltage curves. Furthermore, the system’s sensitivity was found to be 3.8 ng/Hz, with a test molecule (EDA) deposition of about 380 ng in the RF plasma atmosphere. Overall, this study focused on creating a relatively new approach for detecting the real-time mass change in a strong RF environment, which we believe could be an improved and easy-to-set up technique for plasma-based processes such as surface coating, etching, and activation.
Analytical excited state gradients for time-dependent density functional theory plus tight binding (TDDFT + TB)
Authors: Havenridge Shana , Rüger Robert , Aikens Christine M.
Published: June 2023

Understanding photoluminescent mechanisms has become essential for photocatalytic, biological, and electronic applications. Unfortunately, analyzing excited state potential energy surfaces (PESs) in large systems is computationally expensive, and hence limited with electronic structure methods such as time-dependent density functional theory (TDDFT). Inspired by the sTDDFT and sTDA methods, time-dependent density functional theory plus tight binding (TDDFT + TB) has been shown to reproduce linear response TDDFT results much faster than TDDFT, particularly in large nanoparticles. For photochemical processes, however, methods must go beyond the calculation of excitation energies. Herein, this work outlines an analytical approach to obtain the derivative of the vertical excitation energy in TDDFT + TB for more efficient excited state PES exploration. The gradient derivation is based on the Z vector method, which utilizes an auxiliary Lagrangian to characterize the excitation energy. The gradient is obtained when the derivatives of the Fock matrix, the coupling matrix, and the overlap matrix are all plugged into the auxiliary Lagrangian, and the Lagrange multipliers are solved. This article outlines the derivation of the analytical gradient, discusses the implementation in Amsterdam Modeling Suite, and provides proof of concept by analyzing the emission energy and optimized excited state geometry calculated by TDDFT and TDDFT + TB for small organic molecules and noble metal nanoclusters.
Decomposable (5, 6)-solutions in eleven-dimensional supergravity
Authors: Chi Hanci , Chrysikos Ioannis , Schneider Eivind
Published: June 2023

We present decomposable (5, 6)-solutions M̃1,4×M6 in eleven-dimensional supergravity by solving the bosonic supergravity equations for a variety of non-trivial flux forms. Many of the bosonic backgrounds presented here are induced by various types of null flux forms on products of certain totally Ricci-isotropic Lorentzian Walker manifolds and Ricci-flat Riemannian manifolds. These constructions provide an analogy of the work performed by Chrysikos and Galaev [Classical Quantum Gravity 37, 125004 (2020)], who made similar computations for decomposable (6, 5)-solutions. We also present bosonic backgrounds that are products of Lorentzian Einstein manifolds with a negative Einstein constant (in the “mostly plus” convention) and Riemannian Kähler–Einstein manifolds with a positive Einstein constant. This conclusion generalizes a result of Pope and van Nieuwenhuizen [Commun. Math. Phys. 122, 281–292 (1989)] concerning the appearance of six-dimensional Kähler–Einstein manifolds in eleven-dimensional supergravity. In this setting, we construct infinitely many non-symmetric decomposable (5, 6)-supergravity backgrounds by using the infinitely many Lorentzian Einstein–Sasakian structures with a negative Einstein constant on the 5-sphere, known from the work of Boyer et al. [Commun. Math. Phys. 262, 177–208 (2006)].
Electrical, optical, and magnetic properties of amorphous yttrium iron oxide thin films and consequences for non-local resistance measurements
Authors: Roos M. J. , Bleser S. M. , Hernandez L. , Diederich G. M. , Siemens M. E. , Wu M. , Kirby B. J. , Zink B. L.
Published: June 2023

We present magnetic characterization, charge resistivity, and optical photoluminescence measurements on amorphous yttrium iron oxide thin films (a-Y–Fe–O), with supporting comparisons to amorphous germanium (a-Ge) films. We measured magnetic properties with both SQUID magnetometry and polarized neutron reflectometry. These results not only confirm that a-Y–Fe–O is a disordered magnetic material with strong predominantly antiferromagnetic exchange interactions and a high degree of frustration, but also that it is best understood electrically as a disordered semiconductor. As with amorphous germanium, a-Y–Fe–O obeys expectations for variable-range hopping through localized electron states over a wide range of temperature. We also clarify the consequences of charge transport through such a semiconducting medium for non-local voltage measurements intended to probe spin transport in nominally insulating magnetic materials. We further compare non-local resistance measurements made with “quasi-dc” automated current reversal to ac measurements made with a lock-in amplifier. These show that the “quasi-dc” measurement has an effective ac current excitation with frequency up to approximately 22 Hz, and that this effective ac excitation can cause artifacts in these measurements including incorrect sign of the non-local resistance. This comprehensive investigation of non-local resistance measurements in a-Y–Fe–O shows no evidence of spin transport on micrometer length scales, which is contrary to our original work, and in line with more recent investigations by other groups.
Molecular dynamics simulation of the effect of AQP1 on the transmembrane transport of plasma RONS across cancer cell membranes
Authors: Cui Yanxiu , Zhao Tong , Wang Zichen , Wang Xiaolong , Wang Daohan , Zhang Yuantao
Published: June 2023

In the cold atmospheric plasma (CAP)-assisted cancer treatment, the increase in the concentration of reactive oxygen species (ROS) and reactive nitrogen species (RNS) produced by CAP is believed to be related to the overexpression of aquaporins (AQPs) on cancer cell membranes. In this paper, using classical molecular dynamics simulations, the transmembrane behavior of RNS and ROS on a pure phospholipid bilayer or a AQP1-phospholipid bilayer model was studied. The research shows that hydrophobic RNS tend to be transported through the bilayer of phospholipids. The overexpression of AQP1 can significantly improve the transmembrane efficiency of hydrophilic ROS. Our simulation fills the gap in the research for RNS-related molecular simulation and provides guidance for the precise targeting of cancer cells in CAP therapy.
Waveguided energy transfer in pseudo-two-dimensional systems
Authors: Somayaji Hrishikesh , Scholes Gregory D.
Published: June 2023

Resonance energy transfer (RET) is an important and ubiquitous process whereby energy is transferred from a donor chromophore to an acceptor chromophore without contact via Coulombic coupling. There have been a number of recent advances exploiting the quantum electrodynamics (QED) framework for RET. Here, we extend the QED RET theory to investigate whether real photon exchange can allow for excitation transfer over very long distances if the exchanged photon is waveguided. To study this problem, we consider RET in two spatial dimensions. We derive the RET matrix element using QED in two dimensions, consider an even greater confinement by deriving the RET matrix element for a two-dimensional waveguide using ray theory, and compare the resulting RET elements in 3D and 2D and for the 2D waveguide. We see greatly enhanced RET rates over long distances for both the 2D and 2D waveguide systems and see a great preference for transverse photon mediated transfer in the 2D waveguide system.
Long-pulse high-performance H-mode plasmas achieved on EAST
Authors: Huang J. , Gong X. , Garofalo A. M. , Qian J. , Ding R. , Zhang X. J. , Chen J. L. , Li M. H. , Yu Y. W. , Wang Y. F. , Huang Y. , Si H. , Meng L. Y. , Jia T. Q. , Sun Y. X. , Zeng L. , Han L. , Duan Y. M. , Ekedahl A. , Holcomb C. T. , Maingi R. , Li E. Z. , Liu H. Q. , Lyu B. , Ren Q. L. , Sun Y. W. , Wang L. , Xu L. Q. , Yao D. M. , Yang Q. Q. , Zang Q. , Zhang B. , Zhang L. , Zhai X. M. , Zuo G. Z. , Li G. Q. , Zi P. F. , Wang M. , Xu H. D. , Yuan Q. P. , Xie Y. H. , Huang L. S. , Zhang J. , Hu Y. L. , Xi W. B. , Zhou Z. W. , Wang Z. C. , Guo B. , Xu G. S. , Hu J. S. , Lu K. , Song Y. T. , Wan B. N. , Li J. ,   EAST team
Published: June 2023

A record duration of a 310 s H-mode plasma (H98y2 ∼ 1.3, ne/nGW ∼ 0.7, fBS > 50%) has been recently achieved on experimental advanced superconducting tokamak (EAST) with metal walls, exploiting the device's improved long-pulse capabilities. The experiment demonstrates good control of tungsten concentration, core/edge MHD stability, and particle and heat exhaust with an ITER-like tungsten divertor and zero injected torque, establishing a milestone on the path to steady-state long-pulse high-performance scenarios in support of ITER and CFETR. Important synergistic effects are leveraged toward this result, which relies purely on radio frequency (RF) powers for heating and current drive (H&CD). On-axis electron cyclotron heating enhances the H&CD efficiency from lower hybrid wave injection, increasing confinement quality and enabling fully non-inductive operation at high density (ne/nGW ∼ 70%) and high poloidal beta (βP ∼ 2.5). A small-amplitude grassy edge localized mode regime facilitates the RF power coupling to the H-mode edge and reduces divertor sputtering/erosion. The high energy confinement quality (H98y2 ∼ 1.3) is achieved with the experimental and simulated results pointing to the strong effect of Shafranov shift on turbulence. Transport analysis suggests that trapped electron modes dominate in the core region during the record discharge. The detailed physics processes (RF synergy, core-edge integration, confinement properties, etc.) of the steady-state operation will be illustrated in the content. In the future, EAST will aim at accessing more relevant dimensionless parameters to develop long-pulse high-performance plasma toward ITER and CFETR steady-state advanced operation.
Computational study of defect complexes in β-LiGaO2 and their relation to the donor–acceptor-pair recombination
Authors: Dabsamut Klichchupong , Boonchun Adisak , Lambrecht Walter R. L.
Published: June 2023

Hybrid functional calculations are presented for defects in LiGaO2 with the fraction of non-local exchange adjusted to reproduce the recently reported exciton gap of 6.0 eV. We study how the defect transition levels of the main native defects change with respect to the band edges compared to earlier calculations which assumed a smaller bandgap near 5.1 eV. In addition, we consider defect complexes formed by combining the main native donor GaLi with the main acceptors, VLi and LiGa antisites as a function of their relative position. These results are used to tentatively identify the photoluminescence bands previously assigned to donor–acceptor-pair recombination.
Smith–Purcell radiation controlled by the transmission characteristics and quality factor of a layer
Authors: Zhang Ping , Shu Jing , Dong Yin , Zhang Shuhe , Cao Xinxin , Wang Xiaosong , Yang Shengpeng , Liang Bingyang , Zheng Yuan , Wang Shaomeng , Gong Yubin
Published: June 2023

Photonic crystal structures have attracted significant attention because of their ability to confine light, especially outgoing waves in a bandgap. In this study, we investigate a layer that can control the Smith–Purcell radiation. The results show that transmission characteristics and quality factor of a 1D photonic crystal can narrow the radiation spectrum and enhance the radiation intensity. From another perspective, the entire structure can be treated as a composite grating, the radiation spectra of which are obtained by theoretical calculations and agree with that from the analysis based on the role of the 1D photonic crystal. Therefore, it can be concluded that the radiation from a composited structure can be simplified by the radiation controlled by the 1D metal photonic crystal, and it provides a fast way to reshape the radiation spectra by designing the transmission characteristic and quality factor of the photonic crystal. Furthermore, a layer with special transmission characteristics and quality factor above a reflection grating can be used to achieve coherent and tunable Smith–Purcell radiation, which is significant for the development of band-controllable light or terahertz radiation sources.
Investigation of air breakdown and plasma evolution on microstrip antenna surface using the particle-in-cell method
Authors: Jiang Ming , Xie Shaoyi , Hu Linkai , Gao Da , Zhang Lei , Zhu Keyi , Cao Meng
Published: June 2023

This paper investigates the breakdown of two microstrip antennas through experiments and particle-in-cell simulations. The breakdown thresholds of a microstrip dipole antenna and a double-layer patch microstrip antenna are investigated experimentally and found to be 15.6 and 30.8 kW, respectively. Ablation is observed on the surface of the antennas, indicating that the local electric field is particularly intense. To further understand the breakdown process, the particle-in-cell and Monte Carlo collision methods are combined to investigate the inception and development of partial discharge on the surface of the antennas. Under the criterion of continuous electron density growth, the breakdown thresholds of the dipole and double-layer patch antennas are estimated to be 19.4  and 52.9 kW in our simulations. The simulation results are in reasonable agreement with the experimental measurements. In the microstrip dipole antenna, the plasma evolution of the partial discharge is initiated near the tip, while the electric field close to the tip is distorted and a positive streamer directed toward the tip is observed. In the double-layer patch microstrip antenna, a more uniform discharge is observed at the edge of the circular patch in the simulations.
Optimizing Jastrow factors for the transcorrelated method
Authors: Haupt J. Philip , Hosseini Seyed Mohammadreza , López Ríos Pablo , Dobrautz Werner , Cohen Aron , Alavi Ali
Published: June 2023

We investigate the optimization of flexible tailored real-space Jastrow factors for use in the transcorrelated (TC) method in combination with highly accurate quantum chemistry methods, such as initiator full configuration interaction quantum Monte Carlo (FCIQMC). Jastrow factors obtained by minimizing the variance of the TC reference energy are found to yield better, more consistent results than those obtained by minimizing the variational energy. We compute all-electron atomization energies for the challenging first-row molecules C2, CN, N2, and O2 and find that the TC method yields chemically accurate results using only the cc-pVTZ basis set, roughly matching the accuracy of non-TC calculations with the much larger cc-pV5Z basis set. We also investigate an approximation in which pure three-body excitations are neglected from the TC-FCIQMC dynamics, saving storage and computational costs, and show that it affects relative energies negligibly. Our results demonstrate that the combination of tailored real-space Jastrow factors with the multi-configurational TC-FCIQMC method provides a route to obtaining chemical accuracy using modest basis sets, obviating the need for basis-set extrapolation and composite techniques.
Coherent microwave scattering for diagnostics of small plasma objects: A review
Authors: Shashurin Alexey , Patel Adam R. , Wang Xingxing , Sharma Animesh , Ranjan Apoorv
Published: June 2023

Measurements of parameters of small-size plasmas are very challenging because many traditional diagnostic approaches cannot be used. Constructive coherent microwave scattering (CMS) offers a convenient diagnostic solution for such small plasmas. This work reviews the development and applications of constructive coherent microwave scattering by the Electric Propulsion and Plasma Laboratory at Purdue University. It presents fundamentals of CMS with an emphasis on Thomson, collisional, and Rayleigh scattering in short, thin, unmagnetized plasma media. Additionally, we review examples of CMS application for diagnostics of temporally resolved plasma dynamics and electron decay, photoionization rates, electron momentum-transfer collision frequencies, and number densities of selective species in gaseous mixtures. These applications are relevant for various research fields including strong field and femtosecond filamentation physics, plasma-assisted ignition and combustion, and combustion and spacecraft electric propulsion diagnostics.
Phototactic bioconvection with the combined effect of diffuse and oblique collimated flux on an algal suspension
Authors: Panda M. K. , Rajput S. K.
Published: June 2023

The objective of this paper is mainly to investigate the combined effect of diffuse and oblique collimated flux on the onset of phototactic bioconvection. The onset of phototactic bioconvection is examined numerically in a finite-depth algal suspension via linear stability theory. At bioconvective instability, an unstable mode of disturbance shifts from a non-oscillatory (an overstable) to an overstable (a non-oscillatory) state at the variation in oblique incidence angle/diffuse flux for fixed parameters. If n convection cells are piled up on another vertically, then the bioconvective solution of the linear stability problem is called mode n. For some parameters, mode 2 instability is switched to mode 1 instability as the angle of incidence/diffuse flux varies. In addition, diffuse flux (or oblique collimated flux) enhances algal suspension stability (or instability).
Effective properties of graded radially polarized piezoelectric cylindrical composites
Authors: Wei Jia-Qi , Wu Da-Wei , Kaswango Leon
Published: June 2023

This paper presents a theoretical study of a graded piezoelectric composite consisting of an infinitely long graded radially polarized piezoelectric cylinder embedded in an isotropic elastic non-piezoelectric matrix, under an external strain field. The physical properties of the graded cylindrical inclusion have a power-law profile with respect to the cylindrical radial variable. Using the variable separation method, closed-form solutions for the elastic displacement and electrical field in the entire composite regions are derived from the governing equation. The effective elastic and piezoelectric properties of the graded piezoelectric composite are formulated and discussed. The study reveals a vanishing mechanism of effective piezoelectric response in the graded radially polarized cylindrical piezoelectric composite. In addition, the paper derives the effective elastic formulas of the graded cylindrical elastic composites for the purely elastic problem and discusses the effects of graded property parameters on the effective elastic properties.
Energy harvesting using linear type magnetostrictive transducer for real-time application
Authors: Udhayakumar S. , Vasanthan George , Chelvane J. Arout , Bharathi K. Kamala
Published: June 2023

Economic and social development of nations across the globe is demanding enormous need for energy and power resources. Energy production using safe and renewable sources can aid in mitigating the release of greenhouse gases and avoiding the devastating climate changes. In the present case, a linear type magnetostrictive transducer device is designed by employing Terfenol-D magnetostrictive rods for renewable energy harvesting application. A linear device was designed with two Terfenol-D rods, three permanent magnets (neodymium magnets), springs, and primary and secondary coils. Terfenol-D rod crystallizes in cubic Laves phase and exhibits the saturation magnetostriction value of 1242 × 10−6 at the field of 2.5 kOe. An equivalent circuit is constructed for the induced magnetic flux in the designed transducer device. Frequency and wave form dependent output voltage is examined in the designed energy harvesting device. A square wave at the applied frequency of 2200 Hz (100 mA current) produces a maximum output voltage of 4.91 V. Sine and triangle waves produce 3.38 and 2.82 V, respectively, at 1700 and 1600 Hz. The induced voltage is sufficient to ignite the light emitting diode. A linear type magnetostrictive transducer can be employed as a potential renewable energy source for real-time application with moderate output voltage.
The effect of SbCl3 treatment on CdTe produced by close space sublimation method
Authors: Çiriş Ali
Published: June 2023

In this study, influence of SbCl3 treatment on CdTe films deposited by the close space sublimation method was investigated. SbCl3 treatment was compared with conventional CdCl2 treated and untreated samples. It was determined that CdTe grew as Cd-rich and there was a slight decrease in Cd-amount after SbCl3 and CdCl2 treatments. In addition, a significant amount of Sb was detected in the SbCl3 treated sample. The samples crystallized in the cubic structure of CdTe. However, graded structures such as phase-I and phase-II with different structural parameters were formed. In the SbCl3 sample, it was revealed that the presence of Sb- caused a slight increase in the lattice parameter, compared to the other samples. Morphological analyses of the samples showed facet and large-small grain structures. CdCl2 treatment caused a slight decrease in grain size, while SbCl3 treatment resulted in a coarser and rougher grain structure. CdCl2 treatment increased transmittance, whereas SbCl3 treatment caused a decrease in transmittance (hence, an increase in absorbance). It was observed that the bandgaps were ∼1.49 eV in all samples, and annealing, as well as CdCl2 and SbCl3 heat treatments did not cause a sharp change in the bandgaps. Photoluminescence spectra revealed the presence of band-edge and shallow-level defect transitions (except CdCl2 treated) in the samples. All results suggest that SbCl3 heat treatment has a significant effect on CdTe and may be an alternative to CdCl2.
Understanding the high-resolution spectral signature of the N2–H2O van der Waals complex in the 2OH stretch region
Authors: Glorieux R. , Hays B. M. , Bogomolov A. S. , Herman M. , Vanfleteren T. , Moazzen-Ahmadi N. , Lauzin C.
Published: June 2023

We present the observation of the N2–H2O van der Waals complex in the 2OH stretch overtone region. The high-resolution jet cooled spectra were measured using a sensitive continuous wave cavity ringdown spectrometer. Several bands were observed and vibrationally assigned in terms of ν1, ν2, and ν3, the vibrational quantum numbers of the isolated H2O molecule, as (ν1′ν2′ν3′)←(ν1″ν2″ν3″)=(200)←(000) and (101) ← (000). A combination band involving the excitation of the in-plane bending motion of N2 and the (101) vibration of water is also reported. The spectra were analyzed using a set of four asymmetric top rotors, each associated with a nuclear spin isomer. Several local perturbations of the (101) vibrational state were observed. These perturbations were assigned to the presence of the nearby (200) vibrational state and to the combination of (200) with intermolecular modes.
Weakly coupled Majorana wire arrays under tilted magnetic fields
Authors: Rana Deepti , Sheet Goutam
Published: June 2023

An array of Rashba-coupled semiconducting nanowires lying in proximity to an s-wave superconducting substrate, with weak inter-wire coupling, in the presence of an external magnetic field shows even–odd effect in the differential conductance over a chosen parameter space. Such an effect is a direct consequence of end Majoranas in each nanowire hybridizing into bonding and anti-bonding states. In the present work, we study in detail the impact of tilting of external magnetic field on the differential conductance of an array of both uncoupled and weakly coupled wires. The phase diagram evolution with various control parameters including the tilt angle of the magnetic field has also been presented. From detailed analysis of the field-angle dependence of the odd–even effect, and the evolution of the same over a large parameter space we summarize that the results can be used to exploit magnetic-field angle in an array of Rashba-coupled semiconducting nanowires on a superconducting substrate as an important tuning parameter to investigate zero-bias conductance peak arising from Majorana edge modes vis-a-vis that arising from a non-topological origin.
An additive-manufactured microwave cavity for a compact cold-atom clock
Authors: Batori Etienne , Bregazzi Alan , Lewis Ben , F. Griffin Paul , Riis Erling , Mileti Gaetano , Affolderbach Christoph
Published: June 2023

We present an additive-manufactured microwave cavity for a Ramsey-type, double resonance, compact cold-atom clock. Atoms can be laser cooled inside the cavity using a grating magneto-optic trap with the cavity providing an excellent TE011-like mode while maintaining sufficient optical access for atomic detection. The cavity features a low Q-factor of 360 which conveniently reduces the cavity pulling of the future clock. Despite the potential porosity of the additive-manufacturing process, we demonstrate that the cavity is well-suited for vacuum. A preliminary clock setup using cold atoms allows for measuring the Zeeman spectrum and Rabi oscillations in the cavity which enables us to infer excellent field uniformity and homogeneity, respectively, across the volume accessed by the cold atoms. Ramsey spectroscopy is demonstrated, indicating that the cavity is suitable for clock applications. Finally, we discuss the limitations of the future clock.
Electric-field driven source of photocarriers for tunable electron spin polarization in InGaAs quantum dots
Authors: Kise Hiroto , Hiura Satoshi , Park Soyoung , Takayama Junichi , Sueoka Kazuhisa , Murayama Akihiro
Published: June 2023

Electric-field control of spin polarization of electrons during injection into InGaAs quantum dots (QDs) was studied via circularly polarized time-resolved photoluminescence. Electric-field modulation of optical spin polarization in QDs will play a key role in future progress of semiconductor opto-spintronics. The tuning of band potentials by applying external electric fields can not only affect spin-injection efficiencies but also switch dominant spin-injection layers. In this study, we developed a QD-based electric-field-effect optical spin device with two different spin-injection layers, which consisted of a GaAs and GaAs/Al0.15Ga0.85As superlattice (SL) barriers. The bias-voltage modulation of the optical spin polarization in QDs was demonstrated by changing the spin polarization degree of electrons injected from these barriers into the QD via the electric-field switching of the spin-injection layers. This was achieved by exploiting the difference in spin relaxation properties between bulk GaAs and the SL. This proposed structure, which comprised of one luminescent layer and two spin-injection layers, is highly scalable because the modulation range of optical spin polarization can be enhanced by changing the combination of spin-injection layers, as well as the material used and its layer thickness.