bluuebunny/crossref_metadata_2025 huggingface dataset:
Platoon control design for unmanned surface vehicles subject to input delay
Authors: Liang Xiaoling , Zhang Yuexin , Yang Guotao
Published: January 2021

Vessel train formation as a new trend has been raised in cooperative control for multiple vessels. This paper addresses formation control design for a group of unmanned surface vehicles platoon considering input delay. To account for connectivity-preserving and collision-avoiding, Barrier Lyapunov function is incorporated into the constraints design of line-of-sight range and bearing. To alleviate the computational burden, neural dynamic model is employed to simplify the control design and smooth the input signals. Besides, input control arising from time delay due to mechanisms and communication is considered in the marine vessels. Within the framework of the backstepping technique, distributed coordination is accomplished in finite time and the uniformly ultimately boundness of overall system is guaranteed via rigorous stability analysis. Finally, the simulation is performed to verify the effectiveness of the proposed control method.
Influence of forest stand characteristics on physical, mechanical properties and chemistry of chestnut wood
Authors: Marini Francesco , Manetti Maria Chiara , Corona Piermaria , Portoghesi Luigi , Vinciguerra Vittorio , Tamantini Swati , Kuzminsky Elena , Zikeli Florian , Romagnoli Manuela
Published: January 2021

Site conditions and forest management affect dendrometric parameters of chestnut (Castanea sativaMill.) coppices, but there is modest knowledge on the effect of stand dendrometric characters on physical and mechanical wood characteristics. The aim of this study was to verify these relationships in chestnut coppices that were 12–14 years old. Wood density, compression and bending strength, shrinkages were measured on shoots of five different stand in a vulcanic site in Monte Amiata (Central – Italy). Investigated stands differ in number of stools/ha and dominant height, diameter/basal area of the shoots. The main difference in the physical characters among the stands is density. The initial results of the study showed that physical, mechanical wood characters are more dependent by the shoot than by the site. There is a positive relationships between the number of stools/ha and density and a negative one among shoot dominant height and basal area with wood density. Spectroscopic profile by FTIR has not showed relevant differences among the stands. Wood anatomy has showed the breakpoint at cellular level.
Assessing the efficacy of eDNA metabarcoding for measuring microbial biodiversity within forest ecosystems
Authors: Ladin Zachary S. , Ferrell Barbra , Dums Jacob T. , Moore Ryan M. , Levia Delphis F. , Shriver W. Gregory , D’Amico Vincent , Trammell Tara L. E. , Setubal João Carlos , Wommack K. Eric
Published: January 2021

We investigated the nascent application and efficacy of sampling and sequencing environmental DNA (eDNA) in terrestrial environments using rainwater that filters through the forest canopy and understory vegetation (i.e., throughfall). We demonstrate the utility and potential of this method for measuring microbial communities and forest biodiversity. We collected pure rainwater (open sky) and throughfall, successfully extracted DNA, and generated over 5000 unique amplicon sequence variants. We found that several taxa including Mycoplasma sp., Spirosoma sp., Roseomonas sp., and Lactococcus sp. were present only in throughfall samples. Spiroplasma sp., Methylobacterium sp., Massilia sp., Pantoea sp., and Sphingomonas sp. were found in both types of samples, but more abundantly in throughfall than in rainwater. Throughfall samples contained Gammaproteobacteria that have been previously found to be plant-associated, and may contribute to important functional roles. We illustrate how this novel method can be used for measuring microbial biodiversity in forest ecosystems, foreshadowing the utility for quantifying both prokaryotic and eukaryotic lifeforms. Leveraging these methods will enhance our ability to detect extant species, describe new species, and improve our overall understanding of ecological community dynamics in forest ecosystems.
Diabetic condition induces hypertrophy and vacuolization in glomerular parietal epithelial cells
Authors: Kawaguchi Takahisa , Hasegawa Kazuhiro , Yasuda Itaru , Muraoka Hirokazu , Umino Hiroyuki , Tokuyama Hirobumi , Hashiguchi Akinori , Wakino Shu , Itoh Hiroshi
Published: January 2021

Diabetic nephropathy (DN) is accompanied by characteristic changes in the glomerulus, but little is known about the effect of diabetes on parietal epithelial cells (PECs). In this study, a descriptive analysis of PECs was undertaken in diabetic db/db mice and in diabetic patients. PEC hypertrophy was significantly more prominent in diabetic mice than in nondiabetic mice, and this was evident even at the early stage. Additionally, the number of vacuoles in PECs was markedly increased in diabetic mice, suggesting the presence of cellular injury in PECs in DN. Although rare, binuclear cells were observed in mice with early diabetes. In cultured PECs, a high glucose condition, compared with normal glucose condition, induced cellular hypertrophy and apoptosis. Flow cytometry showed that some PECs in the G0 phase reentered the cell cycle but got arrested in the S phase. Finally, in human diabetic subjects, hypertrophy and vacuolization were observed in the PECs. Our data showed that PECs undergo substantial changes in DN and may participate in rearrangement for differentiation into podocytes.
Fall predictors beyond fall risk assessment tool items for acute hospitalized older adults: a matched case–control study
Authors: Noh Hye-Mi , Song Hong Ji , Park Yong Soon , Han Junhee , Roh Yong Kyun
Published: January 2021

We investigated whether clinical factors including comorbidities, medications, and laboratory results predict inpatient fall risk in older adults. The participants in this case–control study included hospitalized older adults with acute conditions who had falls during their hospital stay (case group) and 410 hospitalized older adults who did not experience falls (control group). Data on medical history, fall risk assessment (Morse Fall Scale; MFS), medications, and laboratory results were obtained. Conditional logistic regression analysis was performed to estimate the association between clinical factors and falls. Receiver operating characteristic curves and area under the curve (AUC) were used to determine whether clinical factors could discriminate between fallers and controls. We evaluated three models: (M1) MFS, (M2) M1 plus age, sex, ward, and polypharmacy, and (M3) M2 plus clinical factors. Patients with diabetes mellitus or MFS scores ≥ 45 had the highest risk of falls. Calcium channel blockers, diuretics, anticonvulsants, and benzodiazepines were associated with high fall risk. The AUC of the three models was 0.615, 0.646, and 0.725, respectively (M1 vs. M2, P = 0.042 and M2 vs. M3, P < .001). Examining clinical factors led to significant improvements in fall prediction beyond that of the MFS in hospitalized older adults.
Summer weather conditions influence winter survival of honey bees (Apis mellifera) in the northeastern United States
Authors: Calovi Martina , Grozinger Christina M. , Miller Douglas A. , Goslee Sarah C.
Published: January 2021

Honey bees are crucial pollinators for agricultural and natural ecosystems, but are experiencing heavy mortality in North America and Europe due to a complex suite of factors. Understanding the relative importance of each factor would enable beekeepers to make more informed decisions and improve assessment of local and regional habitat suitability. We used 3 years of Pennsylvania beekeepers’ survey data to assess the importance of weather, topography, land use, and management factors on overwintering mortality at both apiary and colony levels, and to predict survival given current weather conditions and projected climate changes. Random Forest, a tree-based machine learning approach suited to describing complex nonlinear relationships among factors, was used. A Random Forest model predicted overwintering survival with 73.3% accuracy for colonies and 65.7% for apiaries where Varroa mite populations were managed. Growing degree days and precipitation of the warmest quarter of the preceding year were the most important predictors at both levels. A weather-only model was used to predict colony survival probability, and to create a composite map of survival for 1981–2019. Although 3 years data were likely not enough to adequately capture the range of possible climatic conditions, the model performed well within its constraints.
Histamine H1 receptor antagonists selectively kill cisplatin-resistant human cancer cells
Authors: Matsumoto Nobuki , Ebihara Miku , Oishi Shiori , Fujimoto Yuku , Okada Tomoko , Imamura Toru
Published: January 2021

Cancer therapy is often hampered by the disease’s development of resistance to anticancer drugs. We previously showed that the autonomously upregulated product of fibroblast growth factor 13 gene (FGF13; also known as FGF homologous factor 2 (FHF2)) is responsible for the cisplatin resistance of HeLa cisR cells and that it is likely responsible for the poor prognosis of cervical cancer patients treated with cisplatin. Here we show that cloperastine and two other histamine H1 receptor antagonists selectively kill HeLa cisR cells at concentrations that little affect parental HeLa S cells. The sensitivity of HeLa cisR cells to cloperastine was abolished by knocking down FGF13 expression. Cisplatin-resistant A549 cisR cells were similarly susceptible to cloperastine. H2, H3, and H4 receptor antagonists showed less or no cytotoxicity toward HeLa cisR or A549 cisR cells. These results indicate that histamine H1 receptor antagonists selectively kill cisplatin-resistant human cancer cells and suggest that this effect is exerted through a molecular mechanism involving autocrine histamine activity and high-level expression of FGF13. We think this represents a potential opportunity to utilize H1 receptor antagonists in combination with anticancer agents to treat cancers in which emergent drug-resistance is preventing effective treatment.
Thermal transformation of polar into less-polar ginsenosides through demalonylation and deglycosylation in extracts from ginseng pulp
Authors: Yao Fan , Li Xiang , Sun Jing , Cao Xinxin , Liu Mengmeng , Li Yuanhang , Liu Yujun
Published: January 2021

The present study was conducted to qualitatively and quantitatively elucidate dynamic changes of ginsenosides in ginseng pulp steamed under different temperatures (100 or 120 °C) for different durations (1–6 h) through UPLC-QTOF-MS/MS and HPLC with the aid of as numerous as 18 authentic standards of ginsenosides. Results show that levels of eight polar ginsenosides (i.e., Rg1, Re, Rb1, Rc, Rb2, Rb3, F1, and Rd) declined but those of 10 less-polar ginsenosides [i.e., Rf, Rg2, 20(S)-Rh1, 20(R)-Rg2, F4, 20(S)-Rg3, 20(R)-Rg3, PPT, Rg5, and 20(R)-Rh2] elevated with increases of both steaming temperature and duration; the optimum steaming conditions for achieving the highest total ginsenosides were 100 °C for 1 h. Particular, 20(R)-Rg3, a representative less-polar ginsenoside with high bioactivity such as potent anti-cancer effect, increased sharply but Re, the most abundant polar ginsenoside in fresh ginseng pulp, decreased dramatically. More importantly, ginsenoside species enhanced from 18 to 42 after steaming, mainly due to transformation of polar into less-polar ginsenosides. Furthermore, four malonyl-ginsenosides were detected in fresh ginseng pulps and ten acetyl-ginsenosides were formed during steaming, demonstrating that demalonylation and acetylation of ginsenosides were the dominant underling mechanisms for transformation of polar into less-polar ginsenosides.
CROP: a CRISPR/Cas9 guide selection program based on mapping guide variants
Authors: Aprilyanto Victor , Aditama Redi , Tanjung Zulfikar Achmad , Utomo Condro , Liwang Tony
Published: January 2021

The off-target effect, in which DNA cleavage was conducted outside the targeted region, is a major problem which limits the applications of CRISPR/Cas9 genome editing system. CRISPR Off-target Predictor (CROP) is standalone program developed to address this problem by predicting off-target propensity of guide RNAs and thereby allowing the user to select the optimum guides. The approach used by CROP involves generating substitution, deletion and insertion combinations which are then mapped into the reference genome. Based on these mapped variants, scoring and alignment are conducted and then reported as a table comprising the off-target propensity of all guide RNAs from a given gene sequence. The Python script for this program is freely available from: https://github.com/vaprilyanto/crop.
Organic synaptic devices based on ionic gel with reduced leakage current
Authors: Liu Dapeng , Zhao Yiwei , Shi Qianqian , Dai Shilei , Tian Li , Xiong Lize , Huang Jia
Published: January 2021

A solid-state hybrid electrolyte dielectric film was designed for leakage current reduction, synaptic simulation and neuromorphic computing systems.
A multilayered sturdy shell protects silicon nanoparticle Si@void C@TiO2 as an advanced lithium ion battery anode
Authors: Hou Li , Cui Ruiwen , Xiong Shuangsheng , Jiang Xinyu , Wang Dong , Jiang Yang , Deng Shuolei , Guo Yuanyuan , Gao Faming
Published: January 2021

A functional double layer Si-based multi-component structure Si@void C@TiO2 was designed as anode material for lithium-ion batteries with high reversible capacity and long cycle stability.
Role of initial stage nitridation on the mechanical properties of an α-Fe(100) nanofilm in NH3
Authors: Sun Yu , Wang Hao , He Ziqiang , Qiao Baijie , Chen Xuefeng
Published: January 2021

An intermediate temperature leads to optimal mechanical properties of Fe due to the balance of improving the strength while controlling the brittleness.
Theoretical understanding of the properties of stepped iron surfaces with van der Waals interaction corrections
Authors: White Jessica Jein , Liu Junxian , Hinsch Jack Jon , Wang Yun
Published: January 2021

The stepped surfaces in nanoscale zero-valent iron (nZVI) play an essential role for environmental application.
High field parahydrogen induced polarization of succinate and phospholactate
Authors: Berner Stephan , Schmidt Andreas B. , Ellermann Frowin , Korchak Sergey , Chekmenev Eduard Y. , Glöggler Stefan , von Elverfeldt Dominik , Hennig Jürgen , Hövener Jan-Bernd
Published: January 2021

13C isotope effect leads to polarization loss.
Gallium and indium complexes with new hexadentate bis(semicarbazone) and bis(thiosemicarbazone) chelators
Authors: Prado Viviana S. , Leitao Renan C. F. , Silva Francisco , Gano Lurdes , Santos Isabel C. , Marques Fabio L. N. , Paulo António , Deflon Victor M.
Published: January 2021

Rapid, low temperature and high yield synthesis of 67Ga and 111In radiocomplexes with new hexadentate bis(semicarbazone) and bis(thiosemicarbazone) chelators.
MIL-101(Cr) with incorporated polypyridine zinc complexes for efficient degradation of a nerve agent simulant: spatial isolation of active sites promoting catalysis
Authors: Zhang Kai , Cao Xingyun , Zhang Zhiyan , Cheng Yong , Zhou Ying-Hua
Published: January 2021

To achieve the spatial isolation of active sites, zinc polypyridine complexes were incorporated into MIL-101(Cr). Compared with zinc complex without MOF support, the resulting catalyst was highly active for degradation of a nerve agent simulant.
Vascularized organoids on a chip: strategies for engineering organoids with functional vasculature
Authors: Zhang Shun , Wan Zhengpeng , Kamm Roger D.
Published: January 2021

Possible strategy to integrate pre-vascularized organoid and in vitro capillary bed on a microfluidic based platform, aiming for establishing perfused vasculature throughout organoids in vitro.
Discovery of triazolyl thalidomide derivatives as anti-fibrosis agents
Authors: Tang Kai-Wei , Hsu Wen-Li , Chen Cheng-Ru , Tsai Ming-Hsien , Yen Chia-Jung , Tseng Chih-Hua
Published: January 2021

Triazolyl thalidomide derivative10einhibits fibrogenesis by SOCE and TGF-β1/SMAD2/3 signaling pathways.
Efficient photocathode performance of lithium ion doped LaFeO3 nanorod arrays in hydrogen evolution
Authors: Li Yang , Wang Tao , Gao Bin , Fan Xiaoli , Gong Hao , Xue Hairong , Zhang Songtao , Huang Xianli , He Jianping
Published: January 2021

Li-doped LaFeO3 nanorod arrays are used in photoelectrochemical water reduction.
A solid thermal and fast synthesis of MgAl-hydrotalcite nanosheets and their applications in the catalytic elimination of carbonyl sulfide and hydrogen sulfide
Authors: Zhang Guanqing , Kan Xun , Zheng Yong , Cao Yanning , Liang Shijiang , Xiao Yihong , Liu Fujian , Jiang Lilong
Published: January 2021

MgAl hydrotalcites with high exposed OH−sites were designed, and showed superior performance for the catalytic elimination of COS and H2S.
Overcoming thermal quenching in upconversion nanoparticles
Authors: Wang Yanze , Chen Bing , Wang Feng
Published: January 2021

Recent efforts for alleviating energy dissipation and enhancement of energy collection are reviewed to combat thermal quenching in UCNPs.
Tris(pentafluorophenyl)borane catalyzed C–C and C–heteroatom bond formation
Authors: Kumar Gautam , Roy Sourav , Chatterjee Indranil
Published: January 2021

This review showcases a collective depiction on the potential utility of BCF as a versatile catalyst to develop various synthetic transformations.
Phenazines as model low-midpoint potential electron shuttles for photosynthetic bioelectrochemical systems
Authors: Clifford Eleanor R. , Bradley Robert W. , Wey Laura T. , Lawrence Joshua M. , Chen Xiaolong , Howe Christopher J. , Zhang Jenny Z.
Published: January 2021

Phenazines were explored as novel low-midpoint potential molecules for wiring cyanobacteria to electrodes.
Targeted delivery and controlled release of doxorubicin to cancer cells by smart ATP-responsive Y-shaped DNA structure-capped mesoporous silica nanoparticles
Authors: Bagheri Elnaz , Alibolandi Mona , Abnous Khalil , Taghdisi Seyed Mohammad , Ramezani Mohammad
Published: January 2021

In this study, a dual-receptor doxorubicin-targeted delivery system based on mesoporous silica nanoparticles (MSNs) modified with mucine-1 and ATP aptamers (DOX@MSNs-Apts) was developed.
A Gd-doped polydopamine (PDA)-based theranostic nanoplatform as a strong MR/PA dual-modal imaging agent for PTT/PDT synergistic therapy
Authors: Pu Yiyao , Zhu Yuda , Qiao Zi , Xin Nini , Chen Suping , Sun Jing , Jin Rongrong , Nie Yu , Fan Hongsong
Published: January 2021

The construction of a Gd–PDA-Ce6@Gd-MOF (GPCG) theranostic nanosystem which shows enhanced MR/PA imaging performance with great cancer photothermal/photodynamic synergistic therapeutic efficiency under 808/660 nm double laser irradiation.
Understanding the immune responses involved in mediating protection or immunopathology during leishmaniasis
Authors: Pacheco-Fernandez Thalia , Volpedo Greta , Verma Chaitenya , Satoskar Abhay R.
Published: January 2021

Leishmaniasis is a vector-borne Neglected Tropical Disease (NTD) transmitted by the sand fly and is a major public health problem worldwide. Infections caused by Leishmania clinically manifest as a wide range of diseases, such as cutaneous (CL), diffuse cutaneous (DCL), mucosal (MCL) and visceral leishmaniasis (VL). The host innate and adaptative immune responses play critical roles in the defense against leishmaniasis. However, Leishmania parasites also manipulate the host immune response for their survival and replication. In addition, other factors such as sand fly salivary proteins and microbiota also promote disease susceptibility and parasite spread by modulating local immune response. Thus, a complex interplay between parasite, sand fly and the host immunity governs disease severity and outcome. In this review, we discuss the host immune response during Leishmania infection and highlight the factors associated with resistance or susceptibility.
Auto‐calibration Kalman filters for non‐linear systems with direct feedthrough
Authors: Cui Yi , Wang Zhihua
Published: January 2021

The problem of state estimation for non‐linear systems with unknown inputs is discussed. The objective is to construct a non‐linear filter where the unknown input affects both the state equation and measurement equation. An auto‐calibration Kalman filter is proposed with three stages, where the first and second stages are the extension of the two‐stage Kalman filter in non‐linear system cases, and the third stage is the extended Kalman filter with correlated noise. Compared with the two‐stage extended Kalman filter, the presented algorithm conducts a more reasonable linearization of the measurement equation in the third stage. As a result, auto‐calibration is realized and more accurate and more stable state estimation can be obtained. Simulative and practical examples both demonstrate the validity and superiority of the presented auto‐calibration Kalman filter. Furthermore, positioning experiments illustrate that the auto‐calibration Kalman filter can obtain an accurate long‐term heading estimation in pedestrian navigation and is easy to apply in engineering applications.
Stability and stabilisation for switched impulsive positive systems
Authors: Du Shengli , Dong Jiangtao , Wang Yuee
Published: January 2021

The current study is dedicated to addressing the stability and weighted ‐gain performance analysis of switched impulsive positive systems (SIPSs). Firstly, by designing a novel multiple piecewise‐continuous copositive linear Lyapunov function and using the mode‐dependent average dwell time (MDADT) switching method, improved stability conditions that are able to achieve a tighter dwell time bound are developed. It is shown that the system under study is stable and possesses an attenuation property under the designed switching signals. Secondly, with the above stability conditions, a more effective controller design strategy has been proposed. The solved controllers are both quasi‐time dependent and mode‐dependent. Moreover, the constraint on the rank of the controller and the computation burden caused by iteration algorithm used in literature are relaxed. Finally, the feasibility and superiority of the proposed strategies are verified by some simulations.
L4Net: An anchor‐free generic object detector with attention mechanism for autonomous driving
Authors: Wu Yanan , Feng Songhe , Huang Xiankai , Wu Zizhang
Published: January 2021

Generic object detection is a crucial task for autonomous driving. To devise a safe and efficient object detector, the following aspects are required to be considered: high accuracy, real‐time inference speed and small model size. Herein, a simple yet effective anchor‐free object detector named L4Net is proposed, which incorporates a keypoint detection backbone and a co‐attention scheme into a unified framework, and achieves lower computation cost with higher detection accuracy than prior art across a wide spectrum of resource constrains. Specifically, the backbone utilizes Multi‐scale Receptive‐fields Enhancement module (MRE) to capture context‐wise information, where the features of object scale and shape invariance are simultaneously considered. The co‐attention scheme integrates the strength of both Class‐agnostic Attention (CA) and Semantic Attention (SA), and explores the valuable features from low‐level to high‐level to generate more accurate prediction boxes. Compared with previous feature fusion strategy, multi‐scale features are selectively integrated by fully exploiting the different characteristics of low‐level and high‐level features, which leads to a small model size and faster inference speed. Extensive experiments on four well‐known datasets demonstrate the effectiveness of our method. For instance, L4Net achieves 71.68% mAP on KITTI test set, with 13.7 M model size at the speed of 149 FPS on NVIDIA TX and 30.7 FPS on Qualcomm‐based device, respectively, which is 4x smaller and 2x faster than baseline model.
A non‐uniform NSAF‐SF adaptive algorithm
Authors: Xavier P. P. S. , Petraglia M. R. , Haddad D. B.
Published: January 2021

Speech enhancement and acoustic noise reduction are two important tasks where adaptive filtering algorithms emerge as a competitive solution. Unfortunately, in such applications the convergence rate of the system identification is hampered when the excitation data is highly correlated. Subband adaptive algorithms have been developed to address such issue. A recently proposed low‐complexity subband adaptive structure with sparse subfilters is generalised, in order to permit a non‐uniform filter bank structure. This generalisation brings additional flexibility to the resulting critically decimated adaptive structure, which allows one to adapt it to the idiosyncrasies of the application of interest without losing the perfect‐reconstruction property. A closed‐form solution for the optimal values that the adaptive coefficient should assume in order to accurately emulate a given impulse response is derived. Simulations reveal that the resulting algorithm may outperform recently published subband adaptive filtering algorithms, thereby requiring even less computational effort.
A high‐linearity high‐gain up‐conversion mixer for 24 GHz automotive radar applications
Authors: Siddique A. , Delwar T. S. , Ryu J. Y.
Published: January 2021

This paper presents a high conversion gain and highly linearised up‐conversion mixer designed in 65 nm CMOS process, which translates intermediate frequency of 2.4 GHz and local oscillator frequency of 21.6–24 GHz in radio frequency. In the proposed mixer, the tranconductance stage consists of a common source route with neutralisation technique and dual capacitive cross coupled‐common gate route to achieve high linearity and stability. In addition, it also includes dual negative resistance switches with improved inter‐stage matching network to enhance the conversion gain and to decrease the noise figure. The mixer achieves the conversion gain of 4.7 dB, the measured output 1‐dB compression point of 0.41 dBm and noise figure of 3.8 dB at 24 GHz. In an automotive radar application, the proposed mixer showed a high conversion gain, an excellent output 1‐dB and a low noise figure with power consumption of approximately 5.2 mW at a 1.2 V supply.
Maximising robustness and diversity for improving the deep neural network safety
Authors: Esmaeili Bardia , Akhavanpour Alireza , Sabokrou Mohammad
Published: January 2021

This article proposes a novel yet efficient defence method against adversarial attack(er)s aimed to improve the safety of deep neural networks. Removing the adversarial noise by refining adversarial samples as a defence strategy is widely investigated in previous works. Such methods are simply broken if an attacker has access to both main and refiner networks. To cope with this weakness, the authors propose to refine the input samples relying on a set of encoder–decoders, which are trained in such a way to reconstruct the samples on completely different feature spaces. To this end, the authors learn several encoder–decoder networks and force their latent spaces to have a maximum diversion. In this way, if attacker gets access to one of the refiner networks, other ones can play as a defence network. The evaluation of the proposed method confirms its performance against adversarial samples.
Design and analysis of a novel topology for slotless brushless DC (BLDC) motors with enhanced torque and efficiency
Authors: Mousavi‐aghdam Seyed Reza
Published: January 2021

A novel high‐torque slotless brushless DC (BLDC) motor is proposed. The proposed topology has a unique concentrated winding structure and accordingly the motor design is effectively modified with its dual‐rotor structure. The rotor structure of the proposed motor may be modified itself and form three different topologies. First, the basic structures of the new slotless BLDC motor and its operation principle are described. Then, design methodology of the proposed motor is explained. Initial analysis of the motor is subsequently conducted using 2D finite element (FE) simulations. Next, design parameters of the proposed motor are further optimized using Salp algorithm. The proposed topologies are compared with the conventional single and dual‐rotor structures. Finally, experimental prototype is built for verification. The simulation and experimental results exhibit that the proposed slotless BLDC motor has high torque and efficiency in comparison with the conventional structures and may be a good candidate for small‐sized BLDC motors. Moreover, the results show that the proposed BLDC motor has nearly ideal back‐EMF which makes sensorless methods more efficient for the proposed motor.
Improvement of the slotless tubular permanent magnet linear motor with lighter mover mass for punching applications
Authors: Luo Ciyong , Long Xing , Zhu Ziang
Published: January 2021

The slotless tubular permanent magnet linear motor (STPMLM) offers obvious advantages when it is applied to the punching system, such as space saving and controllable impact strength. Herein, the mechanical and electromagnetic coupled differential equations were established to present a comprehensive analysis of the relationship between mover mass and motor performance in the punching system. The travel time of the punching movement was expressed analytically under the condition of the mover obtaining the same impact kinetic energy, and the relationship between the mover mass and the resistive energy consumption in one punching process was also deduced under the same condition. Then the analytical results were validated by a numerical model. The studies show that a lighter mover mass can contribute to less resistive energy consumption and faster dynamic response in the punching applications. Based on that, a STPMLM with special‐shaped yoke was designed for lighter mover mass. Moreover, prototype experiments including static thrust characteristic and dynamic performance were conducted. The experimental results proved that the proposed permanent magnet linear motor with special‐shaped yoke can improve the dynamic performance and reduce resistive energy consumption while ensuring that the electromagnetic performance is not affected.
Online non‐invasive evaluation of arcing time for condition assessment of high‐voltage gas circuit breakers
Authors: Mohammadhosein Milad , Niayesh Kaveh , Shayegani Akmal Amir Abbas , Mohseni Hossein
Published: January 2021

Online non‐invasive methods to assess circuit breaker condition have been under consideration in recent years. The combination of the arcing time and the short‐circuit current recorded by protective relays can be utilized to assess the degrading impact of current interruption on arcing contacts. In many previous investigations, an integral over arcing time of different functions of current and voltage has been proposed to predict the erosion rate of arcing contacts. Although the arcing time is a crucial parameter for these indices, no easily adaptable method to online condition assessment is available. This paper proposes a method for online determination of arcing time based on the measurement of the switching time of the auxiliary contacts. Several experiments have been performed under no‐load conditions as well as during short‐circuit current interruption, on two circuit breakers with different trip coil excitations (AC and DC). The results show that the delay time between the contact separation instant of the arcing contacts and the switching time of the auxiliary contacts has a very low jitter. This enables precise determination of the arcing time by measurement of the switching time of the auxiliary contacts, which is accessible during the online operation of circuit breakers.
An efficient framework for deep learning‐based light‐defect image enhancement
Authors: Ma Chengxu , Li Daihui , Zeng Shangyou , Zhao Junbo , Chen Hongyang
Published: January 2021

The enhancement of light‐defect images such as extremely low‐light, low‐light and dim‐light has always been a research hotspot. Most of the existing methods are excellent in specific illuminations, and there is much room for improvement in processing light‐defect images with different illuminations. Therefore, this study proposes an efficient framework based on deep learning to enhance various light‐defect images. The proposed framework estimates the reflectance component and illumination component. Next, we propose a generator guided by an attention mechanism in the reflectance part to repair the light‐defect in the dark. In addition, we design a colour loss function for the problem of colour distortion in the enhanced images. Finally, the illumination map of the light‐defect images is adjusted adaptively. Extensive experiments are conducted to demonstrate that our method can not only deal with the images with different illuminations but also enhance the images with clearer details and richer colours. At the same time, we prove its superiority by comparing it with state‐of‐the‐art methods under both visual quality comparison and quantitative comparison of various datasets and real‐world images.
Design and research of single‐sided slotted waveguide antenna with a large beam declination
Authors: Zhao Chengwei , Li Xiaoping , Sun Chao , Tian Lishan , Huang He
Published: January 2021

The slot of the conventional longitudinal slot antenna is alternately opened on both sides of the broadside. A novel single‐sided slot array with a large‐declination (biased towards the load) is proposed, in which the slots are only biased to the same side of the waveguide broadside. The main beam declination of a single‐sided slot antenna is only biased towards the load direction and is only related to the broad‐side of the waveguide. To verify the theoretical analysis, a single‐sided slot array with 10‐slot was simulated, fabricated, and measured. According to the measured results, the antenna achieved a beam declination of 25° and a sidelobe level below −22 dB, which is in good agreement with the theoretical analysis. Furthermore, the main beam declination of the single‐sided slot and the traditional double‐sided slot array has been thoroughly studied and compared. When the main beam has a large declination angle (>30°) to the load, a single‐sided slot array is the only choice.
Dielectric‐loaded substrate integrated waveguide H‐plane horn antenna with embedded air cavity
Authors: Huang Sheng , Chan King Yuk , Fu Yunhao , Ramer Rodica
Published: January 2021

A new type of dielectric‐loaded substrate integrated waveguide H‐plane horn antenna with an embedded air cavity is proposed aiming to improve E‐plane performance on a thin substrate. Comparing with recent works, this design attracts superior radiation performance only requiring drilling process to embed a rectangular air cavity in the extended dielectric loading. The measurement results show that at 24.15 GHz, the proposed antenna provides a gain of 13 dBi and 27.7 dB front‐to‐back ratio with narrow 34.3° and 27.3° half‐power beamwidths in E‐ and H‐plane. From 22 to 27 GHz, the side lobe level in E‐plane is reduced below −10 dB. The entire proposed antenna size is 59 × 16 × 3.175 mm.
High scaling ratio line width reduction and fabrication method with electrohydrodynamic jet printing
Authors: E Cheng  , Zhang Tianxiao , Cheng Yu , Li Jinnan , Zhang Zhengyan
Published: January 2021

Electrohydrodynamic (EHD) printing has great potential to be used in the field of electronic industry, precision optics and biological engineering. However, it is still a challenge to achieve a high scaling ratio for line patterns production by EHD jet printing technique, which can effectively prevent the needles to be blocked. In this paper, the influence of the key process parameters on the line width of EHD jet printing was investigated. The printing needle with the inner diameter of 890 μm was used, and the line with width of 3.02 μm was printed by optimizing the parameters. The scaling ratio between the needle inner diameter and the printed line width was up to 295 times. At the same time, the function model between the flow rate and printed line width of PVP/PEO composite was deduced. The error was found to be less than 1% by the verification of experiments. By utilizing this model, the printed line width can be predicted by controlling the flow rate, which will greatly improve the work efficiency. By controlling the flow rate, the goal of printing on demand can be realized. The proposed method and model can provide support for the fabrication of micro‐nano scale structure.
A dynamic functional model of diode bridge rectifier for unbalanced input voltage conditions
Authors: Deriszadeh Adel , Karabasoglu Orkun , Ćalasan Martin P. , Mehdipour Farnaz
Published: January 2021

Diode bridge rectifiers are employed in many industrial applications wherein, under practical operating conditions, input voltages can be occasionally or inherently unbalanced. Using the switching function method, this paper proposes a new accurate functional model of the diode bridge rectifier capable of dealing with unbalanced input voltage conditions. To take all degrees of unbalanced conditions into account, this paper introduces uneven commutation intervals phenomenon between diodes occurring under unbalanced voltage conditions and proposes dynamically updating switching functions.
Grid input current feedback active damping control method for IPMSM drives with small DC‐link capacitor
Authors: Yin Quan , Li Haichun , Luo Hui , Wang Qingyi , Miao Jigui , Hou Yanting
Published: January 2021

With large input line inductance and low dc‐link capacitance, the small dc‐link drive system shows an instability problem, which is mainly caused by LC resonance between the line side inductor and the dc‐link film capacitor. This paper proposes a grid current feedback active damping control method to improve system stability and suppress the LC resonance. The feedback variables are analyzed, and the detected grid current is selected. Thus, the damping current is consistent with the LC resonance components in grid current, which benefits the drive system power factor and grid current quality. Furthermore, the grid current feedback control loop has been established, and the feedback gain is designed based on system parameters that can be adjusted to fit different systems. The stability margin and robustness of the drive system to the changes in line inductance and dc‐link capacitance are improved. Compared with the conventional voltage‐based damping method, the power factor is increased to 0.984 and the grid current harmonics are reduced to satisfy the requirements of EN61000‐3‐2. The effectiveness of the proposed active damping method is verified by the experimental results.
Single‐phase AC‐AC Z‐source converter based on asymmetrical gamma structure with continuous input current and safe commutation strategy
Authors: Mousavi Seyyed Mohammad Javad , Babaei Ebrahim , Alizadeh Darioush , Komurcugil Hasan
Published: January 2021

This paper examines a new topology of the AC‐AC Z‐source converter based on asymmetric Gama structure is proposed. The proposed converter has all the common features such as common ground between input and output, realizing the continuous input current and the ability of boost in‐phase and buck out of‐phase. In order to generate a high voltage gain in the proposed converter, a coupled inductor with Gama structure is used. In this structure, as the turn ratio approaches to one, it gives a higher voltage gain. In order to damping the voltage and current overshoots on the proposed converter switches, a safe commutation strategy is used. Due to the specific topology of the proposed converter, the output filter has been eliminated, so the size and cost of the proposed converter are reduced. Circuit analysis and performance principles are presented in detail and a laboratory prototype implemented to confirm the practicality of the proposed converter.
High‐frequency pulse width modulation noise reduction for permanent magnet synchronous motors using hybrid asymmetrical regular sampled modified space‐vector pulse width modulation
Authors: Zhang Wentao , Xu Yongxiang , Yu Guodong , Zou Jibin
Published: January 2021

This paper proposes a strategy called hybrid asymmetrical regular sampled modified space‐vector pulse width modulation technique in two‐level voltage source inverters. Based on the existing modified space‐vector pulse width modulation, the presented strategy further changes the phase voltage waveform and carrier period, therefore not only eliminating the pulse width modulation noise nearby odd‐order carrier frequency but also reducing the noise around even‐order carrier frequency. Moreover, the frequency band is not elevated due to the periodical varying switching frequency. Under the condition of achieving similar high‐frequency harmonic performance, the proposed strategy will save at least 25% switching loss compared with conventional space‐vector pulse width modulation. Moreover, the dynamic performance of the drive system using the hybrid asymmetrical regular sampled modified space‐vector pulse width modulation can also be improved by asymmetrical regular sample. Implementation process has been introduced and the noise elimination principle has been analysed by mathematical demonstration. Finally, the effectiveness of the proposed strategy has been confirmed by simulation and detailed experimental results.
Open‐switch fault diagnosis in three‐level rectifiers based on selective calculation method for instant voltage deviation
Authors: Chen Mingyun , He Yigang , Sui Chunsong
Published: January 2021

This paper presents an open‐switch fault detection, and identification method for a neutral‐point clamped rectifier system. A new calculation method for phase‐to‐phase pole voltage deviations is proposed for reducing calculation errors. In this way, the more accurate diagnosis can be achieved. Both single‐switch faults, and multiple‐switch faults can be identified effectively by using fewer diagnostic variables, which makes the diagnostic method simpler, and more reliable. And all the variables can be simply calculated by signals which are available to the control system of the rectifier, avoiding the use of additional hardware. Moreover, different voltage thresholds are designed for different faulty feature sections to further reduce the diagnostic time. Additionally, a diagnostic result checking method is proposed to avoid the misdiagnosis when considering the effect of outer‐switch faults. Finally, experiments are carried out, and the results show the robustness, and effectiveness of the proposed method.
Optimal energy management for PV‐integrated residential systems including energy storage system
Authors: Varzaneh S. Ghafouri , Raziabadi A. , Hosseinzadeh Mohammad , Sanjari Mohammad J.
Published: January 2021

Economic profit is the main incentive for PV‐integrated residential prosumers, so energy management algorithms play a key role in these systems. The main priority of conventional rule‐based energy management systems (REMS) is to supply the demand. As a result, the total amount of energy sold to the distribution network, and consequently the user profit in such systems, is not considerable. This study proposes a smart energy management system (SEMS) for optimal energy management in a grid‐connected residential photovoltaic (PV) system, including battery as an energy storage unit. The proposed method, which is simulated by MATLAB, using real values for load and PV characteristics, will result in achieving an economic plan for battery operation based on a discretised state of charge of the battery. Experimental tests, carried out to verify the simulation results, demonstrate a noticeable increase in the prosumer benefits as well as the load profile correction compared to the classic energy management algorithms.
A new impedance measurement method and its application to stability analysis of the inverter‐grid system
Authors: Liu Junliang , Du Xiong , Shi Ying , Tai Heng‐Ming
Published: January 2021

Grid‐connected inverter have been extensively used in the renewable energy grid‐connect systems, such as solar and wind. Interaction between the grid and the inverter may generate harmonic resonances that lead to reduced power quality and even instability. To analyse the stability of the inverter‐grid system using impedance‐based stability criterion, inverter impedance has to be known. Impedance measurement in the dq‐domain requires the precise synchronous phase angle to obtain accurate measurement. For impedance measurement in the stationary frame, inaccuracy usually results from not considering the effects of grid impedance and the frequency coupling. A new impedance measurement method in the stationary frame is proposed to obtain accurate measurement. The proposed method takes into account the grid impedance and its interaction with the inverter. Thus, it overcomes the limitations of current impedance measurement methods. More important, the proposed method enables accurate stability analysis results, whereas current methods may fail. Simulation and experimental results are presented to demonstrate the effectiveness of the proposed measurement method.
Blackstart from HVDC‐connected offshore wind: Hard versus soft energization
Authors: Jain Anubhav , Saborío‐Romano Oscar , Sakamuri Jayachandra N. , Cutululis Nicolaos A.
Published: January 2021

In recent years, renewable energy sources have been integrated on a large scale in power systems all around the world to address the environmental sustainability concerns. With conventional thermal generators being phased out, large offshore wind power plants present a viable alternative to provide blackstart services for power system restoration. By means of simulations, grid‐forming wind turbines are shown to successfully energize the offshore transformer and the high‐voltage direct current (HVDC) export link in a controlled manner, to ultimately supply onshore block load. Two methods for energizing the offshore network have been compared: the prevalent hard‐switching approach and the more complex soft‐start method. Additionally, control has been implemented to mitigate the significant transients in the export link associated with pre‐charging of the onshore converter. It is shown that soft‐start can provide faster energization with smaller transients compared to hard‐switching. Moreover, the sensitivity analyses performed in this study illustrate the impact of pre‐insertion resistor and voltage ramp‐up rates on transients during hard‐switching and soft‐start, respectively. The results presented also show that grid‐forming wind power plants can deal with controlled pre‐charging of the onshore converter from its DC terminals that is essential for the safe energization and operation of the export link.