bluuebunny/crossref_metadata_2025 huggingface dataset:
Corrigendum to: Ammonium metabolism in Selaginella bryopteris in response to dehydration-rehydration and characterisation of desiccation tolerant, thermostable, cytosolic glutamine synthetase from plant
Authors: Singh Kamal K. , Saha Shyamaprasad , Kadiravana Ram C. , Mazumdar Deepika , Rai Vijeta , Ghosh Shilpi
Published: February 2021

Water deficit (WD) has adverse effects on plant growth, and acclimation requires responses allowing primary metabolism to continue. Resurrection plants can serve as model system to gain insight into metabolic regulation during WD. We herein report the response of a resurrection lycophyte, Selaginella bryopteris, to dehydration-rehydration cycle with emphasis on ammonium metabolism. Dehydration of S. bryopteris fronds resulted in decrease of total protein and increase of free ammonium levels and the effect was reversed on rehydration. The proline content increased twice after 24 h of dehydration, which again recovered to background levels comparable to that at full turgor state. The specific activity of glutamine synthetase (GS) didn’t change significantly till 6 h and then declined by 21% after 24 h of dehydration, whereas specific activities of glutamate synthase (GOGAT) and aminating glutamate dehydrogenase (GDH) were enhanced significantly during dehydration. The deaminating activity of GDH also increased during dehydration albeit at a slower rate. Immunoblot analysis indicated overexpression of GS and GDH polypeptides during dehydration and their levels declined on rehydration. The results suggested significant role of GDH along with GS/GOGAT in production of nitrogen-rich amino acids for desiccation tolerance. Unlike higher plants S. bryopteris expressed GS only in cytosol. The enzyme had pH and temperature optima of 5.5 and 60°C, respectively, and it retained 96% activity on preincubation at 60°C for 30 min indicating thermostability. Hence, like higher plants the cytosolic GS from S. bryopteris has a conserved role in stress tolerance.
A stable antimicrobial peptide with dual functions of treating and preventing citrus Huanglongbing
Authors: Huang Chien-Yu , Araujo Karla , Sánchez Jonatan Niño , Kund Gregory , Trumble John , Roper Caroline , Godfrey Kristine Elvin , Jin Hailing
Published: February 2021

Significance

Citrus Huanglongbing (HLB) is the most destructive citrus disease worldwide and has caused billions of dollars in annual production losses, threatening the entire citrus industry. Despite extensive research efforts, there are still no effective management tools to treat HLB-positive trees or to prevent new infections. Current HLB management strategies include chemical application of insecticides and traditional heat-sensitive antibiotics, which pose threats to humans, animal health, and the environment, and likely generate drug resistant insects and microbes. Here, we identified a novel class of stable antimicrobial peptides (SAMPs) from Australian finger lime and other HLB-tolerant citrus close relatives, which has dual functions of inhibiting
C
Las growth in HLB-positive trees and activating host immunity to prevent new infections.
A dark quencher genetically encodable voltage indicator (dqGEVI) exhibits high fidelity and speed
Authors: Alich Therese C. , Pabst Milan , Pothmann Leonie , Szalontai Bálint , Faas Guido C. , Mody Istvan
Published: February 2021

Significance

Voltage sensing with genetically expressed optical probes is highly desirable for large-scale recordings of neuronal activity and detection of localized voltage signals in single neurons. Here we describe a method for a two-component (hybrid) genetically encodable fluorescent voltage sensing in neurons. The approach uses a glycosylphosphatidylinositol-tagged fluorescent protein (enhanced green fluorescent protein) that ensures the fluorescence to be specifically confined to the outside of the plasma membrane and D3, a voltage-dependent quencher. Previous hybrid genetically encoded voltage sensing approaches relied on a single quenching molecule, dipycrilamine (DPA), which is toxic, increases membrane capacitance, interferes with neurotransmitters, and is explosive. Our method uses a nontoxic and nonexplosive compound that performs better than DPA in all aspects of fluorescent voltage sensing.
The RING E3 ligase SDIR1 destabilizes EBF1/EBF2 and modulates the ethylene response to ambient temperature fluctuations in
Arabidopsis
Authors: Hao Dongdong , Jin Lian , Wen Xing , Yu Feifei , Xie Qi , Guo Hongwei
Published: February 2021

Significance

As a gaseous plant hormone, ethylene plays a vital role in plant growth and development as well as the adaptive responses to environmental stimuli. EBF1 and EBF2, which ubiquitinate and degrade the master transcription factors of ethylene signaling (EIN3/EIL1), have emerged as signaling hubs to regulate various physiological processes. Here, we characterized a RING finger E3 ligase SDIR1 that can directly destabilize EBF1/EBF2 to promote the ethylene response. Notably, SDIR1 mediates the temperature-induced protein degradation of EBF1/EBF2 to fine tune the ethylene signaling at different ambient temperatures. This work elucidates another layer of ethylene signal transduction and advances our understanding of the complex mechanisms underlying the environmental control of ethylene signaling.
The Covid infodemic
Authors: Hyland Ken , Jiang Feng (Kevin)
Published: February 2021

Covid-19, the greatest global health crisis for a century, brought a new immediacy and urgency to international bio-medical research. The pandemic generated intense competition to produce a vaccine and contain the virus, creating what the World Health Organization referred to as an ‘infodemic’ of published output. In this frantic atmosphere, researchers were keen to get their research noticed. In this paper, we explore whether this enthusiasm influenced the rhetorical presentation of research and encouraged scientists to “sell” their studies. Examining a corpus of the most highly cited SCI articles on the virus published in the first seven months of 2020, we explore authors’ use of hyperbolic and promotional language to boost aspects of their research. Our results show a significant increase in hype to stress certainty, contribution, novelty and potential, especially regarding research methods, outcomes and primacy. Our study sheds light on scientific persuasion at a time of intense social anxiety.
Relativistic R-matrix calculations of the photoionization of W63+ ions
Authors: An Y H , Wu Z W , Jiang J , Xie L Y , Zhang D H , Dong C Z
Published: February 2021

The direct and resonant single-photon photoionization of W63+ ions from their ground state 1s
22s
22p
63s
2
S
1/2 and four lowly-excited states 1s
22s
22p
63p
2
P
1/2,3/2 and 1s
22s
22p
63d
2
D
3/2,5/2 has been studied within the framework of the relativistic R-matrix method and the multiconfigurational Dirac–Fock method. Special attention has been paid to obtaining direct and resonant ionization limits and to identifying possible resonant symmetries of W63+ ions. To this end, the photoionization cross-sections have been calculated using the Dirac Atomic R-matrix Code package. Direct and resonant ionization limits were obtained for the ground-state photoionization of W63+ ions, and the resonant peaks identified were found to be associated with the resonances 1s
22s
22p
53lnl′ and 1s
22s2p
63lnl′ (l, l′ = s, p, d) for the fine-structured energy level or configuration at the level of fine structure or configuration. For excited-state photoionization, however, the resonant ionization limits and resonant peaks were hardly distinguishable due to much more densely spaced resonant peaks and a complicated resonant structure, although the respective direct ionization limits are obtained. We expect that this work will remedy the current lack of fundamental studies of the photoionization of W63+ ions and be helpful in the diagnosis and simulation of fusion plasmas in conjunction with the available photoionization data for tungsten ions in other charge states.
‘Dancing dolls in resonance’: a simple design-and-make STEAM toy project to promote student interest and engagement in physics
Authors: Amir Nazir , Abdullah Nor’Aini Bte
Published: February 2021

A way to promote student interest and engagement in physics is by capitalizing on students’ skills in arts and crafts to design and make physics-based toys. This article illustrates how two students (averaging 14 years of age) in the authors’ science class designed and fabricated a variation of a physics-based teaching aid that demonstrates the concept of resonance. The students value-added to the appeal of this teaching aid by adding ‘artful’ and ‘game-like’ contexts that aroused the curiosity of their classmates and young children in the functionality of the toy.
The ‘SXR—Pit’ paradox as an indicator of electron transport in tokamaks
Authors: Mirnov S V
Published: February 2021

A phenomenon is analyzed, which is observed at some laboratory-scale tokamaks and seems to be unexplained: a strong drop in the soft x-ray radiation (SXR) after it passed through the ‘thick’ Be foils (the pit in the SXR spectrum). This phenomenon becomes more pronounced as the foil thickness increases and the plasma electron density decreases. The explanation for this phenomenon is proposed, which involves the assumption that the Maxwellian electron velocity distribution becomes ‘depleted’ in the range of velocities that are 3–5 times higher than the thermal one. The anomalous electron heat transport along the weakly perturbed toroidal magnetic field of the tokamak (the ‘magnetic flutter’ model) seems to be the most probable reason for this depletion. Thus, the ‘SXR—Pit’ can be a new tool for studying the physical nature of the anomalous electron transport in tokamaks.
Omnidirectional and compact Tamm phonon-polaritons enhanced mid-infrared absorber*
Authors: Hua Xiaomin , Zheng Gaige , Xian Fenglin , Xu Dongdong , Wang Shengyao
Published: February 2021

Narrow band mid-infrared (MIR) absorption is highly desired in thermal emitter and sensing applications. We theoretically demonstrate that the perfect absorption at infrared frequencies can be achieved and controlled around the surface phonon resonance frequency of silicon carbide (SiC). The photonic heterostructure is composed of a distributed Bragg reflector (DBR)/germanium (Ge) cavity/SiC on top of a Ge substrate. Full-wave simulation results illustrate that the Tamm phonon-polaritons electric field can locally concentrate between the Ge cavity and the SiC film, contributed to the improved light-phonon interactions with an enhancement of light absorption. The structure has planar geometry and does not require nano-patterning to achieve perfect absorption of both polarizations of the incident light in a wide range of incident angles. Their absorption lines are tunable via engineering of the photon band-structure of the dielectric photonic nanostructures to achieve reversal of the geometrical phase across the interface with the plasmonic absorber.
Intercalation of germanium oxide beneath large-area and high-quality epitaxial graphene on Ir(111) substrate*
Authors: Wang Xueyan , Guo Hui , Lu Jianchen , Lu Hongliang , Lin Xiao , Shen Chengmin , Bao Lihong , Du Shixuan , Gao Hong-Jun
Published: February 2021

Epitaxial growth on transition metal surfaces is an effective way to prepare large-area and high-quality graphene. However, the strong interaction between graphene and metal substrates suppresses the intrinsic excellent properties of graphene and the conductive metal substrates also hinder its applications in electronics. Here we demonstrate the decoupling of graphene from metal substrates by germanium oxide intercalation. Germanium is firstly intercalated into the interface between graphene and Ir(111) substrate. Then oxygen is subsequently intercalated, leading to the formation of a GeO
x
layer, which is confirmed by x-ray photoelectron spectroscopy. Low-energy electron diffraction and scanning tunneling microscopy studies show intact carbon lattice of graphene after the GeO
x
intercalation. Raman characterizations reveal that the intercalated layer effectively decouples graphene from the Ir substrate. The transport measurements demonstrate that the GeO
x
layer can act as a tunneling barrier in the fabricated large-area high-quality vertical graphene/GeO
x
/Ir heterostructure.
Surface plasmon polaritons frequency-blue shift in low confinement factor excitation region*
Authors: Hu Ling-Xi , He Zhi-Qiang , Hu Min , Liu Sheng-Gang
Published: February 2021

Surface plasmon polaritons’ (SPPs’) frequency blue shift is observed in finite-difference time-domain (FDTD) simulation of parallel electron excitation Au bulk structure. Comparing with cold dispersion of SPPs, an obvious frequency blue shift is obtained in low confinement region excitation simulation results. Then, according to SPPs’ transverse attenuation characteristics, the excited frequency mode instead of cold dispersion corresponding frequency mode matches it. Thence, this excited mode is confirmed to be SPPs’ mode. As is well known the lower the frequency, the smaller the confinement factor is and the lower the excitation efficiency, the wider the bandwidth of excited SPPs is. And considering the attenuation in whole structure, the excited surface field contains attenuation signal. In a low confinement factor region, the higher the SPPs’ frequency, the higher the excitation efficiency is, while broadband frequency information obtained in attenuation signal provides high frequency information in stimulation signal. Thence, in the beam–wave interaction, as the signal oscillation time increases, the frequency of the oscillation field gradually increases. Thus, compared with cold dispersion, the frequency of excited SPP is blueshifted This hypothesis is verified by monitoring the time domain signal of excited field in low and high confinement factor regions and comparing them. Then, this frequency-blue shift is confirmed to have commonality of SPPs, which is independent of SPPs’ material and structure. Finally, this frequency-blue shift is confirmed in an attenuated total reflection (ATR) experiment. Owing to frequency dependence of most of SPPs’ devices, such as coherent enhancement radiation and enhancement transmission devices, the frequency-blue shift presented here is of great influence in the SPPs applications.
X-ray emission for Ar11+ ions impacting on various targets in the collisions near the Bohr velocity*
Authors: Zhou Xian-Ming , Wei Jing , Cheng Rui , Chen Yan-Hong , Mei Ce-Xiang , Zeng Li-Xia , Liang Chang-Hui , Li Yao-Zong , Zhao Yong-Tao , Zhang Xiao-An
Published: February 2021

X-ray emission from the collisions of 3 MeV Ar11 + ions with V, Fe, Co, Ni, Cu, and Zn is investigated. Both the x-rays of the target atom and projectile are observed simultaneously. The x-ray yield is extracted from the original count. The inner-shell ionization cross section is estimated by the binary encounter approximation model and compared with the experimental result. The remarkable result is that the Ar K-shell x-ray yield is diminished with the target atomic number increasing, which is completely opposite to the theoretical calculation. That is interpreted by the competitive consumption of the energy loss for the ionization of inner-shell electrons between the projectile and target atom.
Generation of wideband tunable femtosecond laser based on nonlinear propagation of power-scaled mode-locked femtosecond laser pulses in photonic crystal fiber*
Authors: Lv Zhiguo , Teng Hao
Published: February 2021

We implement an experimental study for the generation of wideband tunable femtosecond laser with a home-made power-scaled mode-locked fiber oscillator as the pump source. By coupling the sub-100 fs mode-locked pulses into a nonlinear photonic crystal fiber (NL-PCF), the exited spectra have significant nonlinear broadening and cover a spectra range of hundreds of nm. In experiment, by reasonably optimizing the structure parameters of NL-PCF and regulating the power of the incident pulses, femtosecond laser with tuning range of 900–1290 nm is realized. The research approach promotes the development of femtosecond lasers with center wavelengths out of the traditional laser gain media toward the direction of simplicity and ease of implementation.
Serverless distributed learning for smart grid analytics*
Authors: Huang Gang , Wu Chao , Hu Yifan , Guo Chuangxin
Published: February 2021

The digitization, informatization, and intelligentization of physical systems require strong support from big data analysis. However, due to restrictions on data security and privacy and concerns about the cost of big data collection, transmission, and storage, it is difficult to do data aggregation in real-world power systems, which directly retards the effective implementation of smart grid analytics. Federated learning, an advanced distributed learning method proposed by Google, seems a promising solution to the above issues. Nevertheless, it relies on a server node to complete model aggregation and the framework is limited to scenarios where data are independent and identically distributed. Thus, we here propose a serverless distributed learning platform based on blockchain to solve the above two issues. In the proposed platform, the task of machine learning is performed according to smart contracts, and encrypted models are aggregated via a mechanism of knowledge distillation. Through this proposed method, a server node is no longer required and the learning ability is no longer limited to independent and identically distributed scenarios. Experiments on a public electrical grid dataset will verify the effectiveness of the proposed approach.
Absence of magnetic order in dichloro [1,2-bis (diphenylphosphino) ethane] nickel2+ single crystal*
Authors: Ma Shuaiqi , An Linlin , Zhu Xiangde
Published: February 2021

Dichloro [1,2-bis (diphenylphosphino) ethane] nickel2+ (NiCl2(dppe)) is an organic compound containing C26H24P2(dppe) molecules and Cl−, Ni2+ ions. The large-size NiCl2(dppe) single crystals with longest dimension of 4 mm were grown by the method of slow evaporation of organic solution. Single crystal x-ray diffraction spectrum indicates that the single crystal is of high quality. Magnetization results of the NiCl2(dppe) single crystals show an anisotropic paramagnetism behavior and diamagnetic background, which come from Ni2+ ions and benzene ring, respectively. However, according to the specific heat results with temperature down to 0.1 K and magnetic field up to 14 T, no expected field-induced quantum phase transition was observed in NiCl2(dppe) single crystals.
Target–background contrast enhancement based on a multi-channel polarization distance model
Authors: Zhong Binbin , Wang Xin , Wang Daqian , Yang Tian , Gan Xin , Qi Zhongjian , Gao Jun
Published: February 2021

Stomatopods are creatures that have a unique ability to manipulate their environment by detecting polarized light for finding prey, choosing habitat, and navigation. In this study, based on the concept of polarization distance proposed by Martin J et al 2014 [Proc. R. Soc. B
281, 20131632], we have analyzed several multi-channel polarization distance models. The simulation and experimental results revealed that compared to other models, a four-channel polarization distance model can significantly enhance the contrast between the target and the background, and it exhibits excellent performance in terms of scene discrimination capability and robustness to noise. The structure and signal processing method of this model are inspired by biological polarization vision such as that of mantis shrimps. According to this method, a polarization-vision neural network is simulated with four-orientation receptor information as the input, and the network connections are realized in a cascaded order. The target–background contrast enhancement method based on this model has wide application prospects in the field of camouflage removal and target detection.
3D printing-assisted fabrication of a patient-specific antibacterial radial head prosthesis with high periprosthetic bone preservation
Authors: Maydanshahi Mohammad Reza , Nazarian Ara , Eygendaal Denise , Ebrahimzadeh Mohammad Hossein , Kachooei Amir Reza , Mousavi Shaegh Seyed Ali
Published: February 2021

We present a novel fabrication and surgical approach for anatomical reconstruction of a fractured radial head using a patient-specific radial head prosthesis (RHP) made of polymethylmethacrylate (PMMA) bone cement. To this end, the use of PMMA bone cement for prosthesis fabrication was initially investigated using computational modeling and experimental methods. The RHP was fabricated through casting of PMMA bone cement in a silicone mold in the operating room before implantation. To enhance the precision of bony preparation for replacement of the radial head, a patient-specific surgical guide for accurate resection of the radial neck with the desired length was developed. Post-surgical clinical examinations revealed biomechanical restoration of elbow function, owing to the use of the patient-specific RHP and surgical guide. Importantly, follow-up radiographs after a mean follow-up of 18 months revealed bone preservation at the bone–prosthesis interface without any signs of erosion of the capitellum. Taken together, our method demonstrated the safety and efficacy of the PMMA RHP in restoring elbow biomechanics. This also provides a very safe and cost-effective method for making various patient-specific prostheses with localized antibacterial delivery and close mechanical properties to native bone for improved periprosthetic bone regeneration. The clinical trial of this study was registered at Mashhad University of Medical Sciences under the trial registration number 970493.
An LSTM-based neural network method of particulate pollution forecast in China
Authors: Chen Yarong , Cui Shuhang , Chen Panyi , Yuan Qiangqiang , Kang Ping , Zhu Liye
Published: February 2021

Particulate pollution has become more than an environmental problem in rapidly developing economies. Large-scale, long-term and high concentration of particulate pollution occurs much more frequently, which not only affects human health but also economic production. As PM10 is one of the main pollutants, the prediction of its concentration is of great significance. In this study, we present a PM10 forecast model based on the long short-term memory (LSTM) neural network method and evaluate its performance of predicting PM10 daily concentrations at five representative cities (Beijing, Taiyuan, Shanghai, Nanjing and Guangzhou) in China. Our model shows excellent adaptability for various regions in China. The predicted PM10 concentrations have good correlations with observations (R = 0.81–0.91). We also achieve great predication accuracy (70%–80%) on predicting the next-day changing trend and the model has the best performance for heavy pollution situation (PM10 > 100 μg m−3). In addition, the comparison of LSTM-based method and other statistical/machine learning methods indicates that our model is not only robust to different pollution intensities and geographic locations, but also with great potential on pollution forecast with temporal-correlated feature.
How environmental values influence trust and beliefs about societal oversight and need for regulation of the Australian cattle industry
Authors: Witt G B , Althor G , Colvin R M , Witt K J , Gillespie N , McCrea R , Lacey J , Faulkner T
Published: February 2021

Livestock grazing covers half of Australia and vast areas of global terrestrial ecosystems. The sustainability of the beef cattle industries are being scrutinised amid ongoing environmental concerns. In response, industry discourse has identified public trust as critical to avoiding reactive environmental regulation. However, public perceptions of the cattle industry’s sustainability performance and trust are largely unknown and speculative. We present the first model of public attitudes toward the Australian cattle industry (n = 2913). Our results reveal that societal perceptions of the industry’s environmental performance strongly predict trust in the industry. However, trust only weakly predicts a perceived right for societal oversight and has only an indirect relationship on need for environmental regulation. Environmental values influence perceptions of industry performance and the perceived right for societal oversight. We conclude that effective industry governance must be values literate and recognise that strong environmental performance is critical for public trust. Public trust is high but does not translate to support for a relaxed regulatory environment.
Development of an intelligent ergonomic model for Hazards predictions in Domestic Tasks
Authors: Adeyemi H O
Published: February 2021

Behavioural pattern is linked to many home accidents among occupants which have caused many injuries to life and properties. This study considered the categories and prevalence of risks among women in domestic tasks. A model was developed to predict the safety level of the subjects using Artificial Neural Network (ANN) function. With the use of a structured questionnaire, the study was conducted among 169 unmarried and 171 married women and the data was analysis with SPSS software. The ANN function was developed using the participants’ conducts in performing house chore duties, as the input. The “level of safety” was the output of the system. To test for its functionality, the ANN system was applied to predict safety in the performance of regular domestic duties among some women in the study area. The prediction accuracy of the system met with the objectives of the study. Among the widely reported, 40% of the participants suffered from ‘Cuts injury’ and while 35.6% complained of ‘contact with hot objects’. The developed ANN system is useful in homes where women are deeply engaged in domestic work.
Reliability of a capacitated system with parallel subsystems considering performance sharing mechanism
Authors: Ma Ye , Wu Di , Gao Kaiye , Li Yingchun , Peng Rui
Published: February 2021

Performance sharing mechanism is widely applied in energy systems, computing systems and other types of industrial systems to increase system reliability. In reality, some systems may allow certain extent of performance deficiency instead of requiring every subsystem in the system satisfy its demand. Moreover, the subsystems in systems may combine with amounts of components, say that, a series of generators should be simultaneously used to provide the necessary energy for a given area. In this paper, we consider a system with performance sharing mechanism where the system remains functional as long as the summed weighted deficiency for subsystems after performance sharing is smaller than a predesigned reliable threshold. The amount of shared performance is further assumed to restricted by the bandwidth capacity of the system. We further consider the case where the surplus can be redistributed to maximize system reliability. Universal generating function technique is employed to model the reliability of the system and numerical examples are provided to illustrate the applications.
An information aggregation method for hierarchical system reliability analysis with insufficient reliability information based on Bayesian Melding Method
Authors: Xu Yingchun , Yao Wen , Chen Xiaoqian , Liu Jianfeng , Wang Sheng , Chen Xing , Zhou Tao
Published: February 2021

In practical engineering, the reliability analysis of the hierarchical system structure is a hot topic, which has made great progress in recent years. From former experiments, there exists multi-source reliability information for the complex system. In the literature, the Bayesian Melding Method is a useful tool to merge the subsystem and system information based on the deterministic structure. However, when the system reliability information is insufficient, how to integrate the limited information for the system reliability analysis remains a problem to be solved. In this paper, an information aggregation method is developed for the hierarchical system to make full use of the limited reliability information based on the traditional Bayesian Melding Method. Three main steps are involved in the proposed method, i.e. distribution assumption, structure reconstruction, and reliability inference, based on which the existed reliability information can be fully merged and partial missing reliability information can be acquired through the system structure. Finally, the benefit illustration and effectiveness verification of the proposed method are given in the numerical example.
Research on the construction of supportability index of aviation equipment system of systems
Authors: Ding Gang , Cui Li-Jie , Wang Li-Yong , Hu Rong , Qian Guang
Published: February 2021

According to the characteristics of the air force operation under the condition of informationization, the concept, connotation and characteristics of the supportability of the AESos(Aviation equipment system of systems) based on task are defined. Based on the supportability logical control relation of the AESos, the capability requirements of the system to different levels are defined, and the requirement of the system support capability is described in particular. Secondly, following the idea of model-capability-index, and on the basis of constructing the supportability index system of AESos, the paper puts forward three system-level indexes to evaluate the supportability of the AESos, which are the intact rate of the AESos, the availability of the AESos and the mission continuity probability of the AESos.Finally, the definition and calculation formula of the three system-level indexes are given, which can lay a foundation for modeling and analyzing the supportability of the AESos. It provides support for the evaluation, control, overall planning and optimization of maintenance support capability of modern AESos.
Research on Backup Strategy of BeiDou Global Navigation System Constellation
Authors: Qinghua Wang , Haitao Zhao , Lei Chen , Zhaozhao Gao , Xiaofang Zhao
Published: February 2021

BeiDou Global Navigation System (BDS-3) will be fully completed by 2020, and provide global users with high-quality services including positioning, navigation and timing, global short messages communication (GSMC), international search and rescue(SAR) etc. Compared with the regional navigation system, the global navigation system serves a wider area and more users, and the consequences are more serious in the event of a service outage. It is necessary to study the backup strategy of the space segment as early as possible in the early stage of system operation. Firstly, the paper analyses the effects of three kinds of satellite in different positions on the system performance, then analyses the probability distribution of multiple satellites failure, and then puts forward the satellite backup strategy. From the perspectives of improving GSMC coverage and increasing the available time of SAR, combined with the remaining life and configuration of the satellites in orbit, the orbit positions of redundancy satellites are suggested. The analysis results show that if one or two satellites are backed up in three MEO orbital planes, the robustness of the system will be improved effectively, and the availability of the system will be guaranteed even if any satellite fails. Furthermore, if four satellites equipped with SAR and GSMC load are backed up in proper phase on the first and third orbit planes, the availability of GSMC service will reach 100% in the global scope, and the availability of SAR service will be significantly improved.
Comprehensive Evaluation for Design for Design Scheme of Metro Auxiliary Power supply System Based on FAHP
Authors: Gong Q , Chen B Z , Zhi P P , Li Y H
Published: February 2021

Considering the main factors that affect the design scheme of power supply system, the fuzzy analytic hierarchy process (FAHP) is used to comprehensively evaluate the design scheme of metro auxiliary power supply system. Firstly, the evaluation model of the auxiliary power supply system design scheme is established, and the factors influencing the system evaluation are divided into two levels, and the factor evaluation grade is the third level. Secondly, analytic hierarchy process (AHP) is used to determine the weight of each factor, and the method of triangular fuzzy number is used to establish a comprehensive evaluation matrix. Finally, the three-level fuzzy comprehensive evaluation is carried out based on the principle of fuzzy transformation, and the comprehensive evaluation results of each design scheme are calculated. The research results show that the comprehensive evaluation score of the parallel centralized power supply mode is the highest, and the design scheme is the best, which is consistent with the actual application. It shows that the method can directly reflect the advantages and disadvantages of each design scheme, and provide some reference for the selection of the design scheme of the auxiliary power supply system of the metro.
Time-dependent reliability moment-independent global sensitivity analysis of planar motion mechanisms
Authors: Guo Q , Liu Y S , Chen B Q
Published: February 2021

The planar motion mechanisms are widely applied in aerospace field to realize the scheduled output. A moment-independent global sensitivity analysis method (MIGSA) is developed for time-dependent reliability of planar motion mechanisms. The defined sensitivity index can indicate the influence of the uncertainty of the input variables in the entire uncertain region on time-dependent reliability of the planar motion mechanisms. An active learning Kriging (ALK) model is established to solve time-dependent failure probability as well as sensitivity index efficiently. A representative rack-and-pinion steering linkage example is investigated for validating its significance of the time-dependent reliability MIGSA method in this paper, and the efficiency of ALK method for approximating the time-dependent reliability MIGSA index.
Reliability analysis of mixer structure under mixing simulation
Authors: Cheng Hai-Ying , Luo Zhun , Yong Liang
Published: February 2021

When the forced two-horizontal shaft mixer is used to mix concrete, the mixing drum and the mixing components are subjected to random loads of the mixture. Structural static analysis usually ignores the randomness of the load, resulting in a large calculation error. Based on the EDEM software, this paper simulates the mixing process of the mixture, obtains the random load data of the mixture on the mixing drum and the mixing parts, and describes the variation law of the random load with a probability distribution, establishes the stress-strength interference reliability model of the mixer structure, and Monte Carlo simulation method is used to solve the structural reliability of the mixer. The results show that the load distribution of the mixing arm is the same as the mixing blade, the load distribution follows the gamma distribution, and the mixing shaft also follows the gamma distribution; the load distribution of the mixing drum follows the normal distribution. After calculation, the above load probability distribution and its intensity distribution do not interfere, and the structural reliability of the mixer meets the requirements, which can ensure the safe operation of the mixer. This method solves the reliability calculation error caused by random loads.
Modelling and Failure Analysis of SiC MOSFET under the Effects of Parasitic Parameters
Authors: Ye Xuerong , Wang Haonan , Lai Yaokang , Zhai Guofu , Cao Yufeng
Published: February 2021

Recent years, SiC MOSFET has been gradually utilized in high power devices. However, it has become one of the highest failure rate devices in circuit systems. Its failure relates to the degradation which caused by the hot carrier injection(HCI) effect. Because the parasitic parameters make the oscillations in switching processes more intense, the switching time and voltage overshoot increases, and thus HCI effect exacerbates. So, it is necessary to analyse the influence of parasitic parameters on the failure of SiC MOSFET. In this paper, an improved SiC MOSFET model with all key parasitic parameters is built to set up an accurate test circuit. The parasitic parameters were divided into four parts: body diode, parasitic resistance, parasitic capacitance and parasitic inductance. According to the simulation, it concluded that only the parasitic inductance has a great impact on the HCI effect and the impacts are different according to the different locations of parasitic inductance. The influence of the parasitic inductance on the load circuit and near the source is much greater than other parts. Their increase greatly increases switching time and voltage overshoot, and thus exacerbates HCI effect and accelerates the degradation of SiC MOSFET.
Using data mining and root cause analysis method for failure analysis in electronic components
Authors: Wang Hongjian , Zhao Zhenbo , Dai Zongbei , Peng Zeya , Li Shaoping
Published: February 2021

The electronic components are the core of all electronic products, the reliability and maintainability directly affect manufacture products quality. And as products become more complex and more demanding. We need more reliable components. In order to solve this problem, we need to analysis how and why those components failed. Failure analysis cases are important data for analysis, data mining and improving reliability. China Electronic Product Reliability and Environment Testing Research Institute (CEPREI) is the earliest research organization engaged in reliability research and failure analysis in China, and has accumulated rich failure case data. By combining data mining methods such as Bayesian network, correlation analysis, we can perform statistical analysis and root cause analysis to assist failure analysis and improve product reliability. This paper will apply the failure analysis case of the electromagnetic relay, and explores and analyses related regular pattern.
Reliability Engineering Design Method based on Generalized Margin Design theory
Authors: Peng Wensheng , Li Yonghong
Published: February 2021

Traditional reliability indexes in engineering are statistic parameters of failure time or failure rates, these reliability parameters are not related to products’ design parameters directly. In fact, reliability design in engineering process is margin design, for instance, the safety factors approach, the derating design approach, and even the selection of the high quality components carried out by enhancing the margin of resisting the sense stress of failures. This paper proposes a reliability engineering design method based on the general margin theory, and the quantification relationships between the statistic reliability parameters and general margin parameters are established. The general margin proposed in this paper contains the stress margin and function margin. The margin design rules and requirements are defined according to the products(or concepts design) ‘s loads in the predicted lifecycle; and then the stress margin parameters that satisfying the reliability could be determined based on the stress-strength interference model, and these margin parameters could support the products concepts selection; if the stress margin parameters could not satisfy the requirements, then the function margin parameters are analyzed to guide the key function redundancy design until the reliability of the products are meet. This method could improve the suitability of reliability theory in engineering field. This paper demonstrates the availability of this design method with a case study.
A Fault Diagnosis Algorithm for Wind Turbine Blades Based on BP Neural Network
Authors: Bi Jun-Xi , Fan Wen-Ze , Wang Ying , Ren Jun , Li Hai-Bin
Published: February 2021

As one of the most critical wind power generation components, wind turbine blades play a key role in generating wind power. Aiming at the problem that the wind turbine blades are subjected to multiple loads in combination, the crack problem is easy to occur. Through the analysis of the macroscopic expansion mechanism and microscopic damage mechanism of short cracks and main cracks, the hidden relationship between crack appearance and damage nature is deeply explored. A fault diagnosis algorithm for wind turbine blades established on the basis of the BP neural network is raised. On the multi-discriminator fusion network structure, BP neural network algorithm is used to train the multi-feature sample data including wind turbine blades, so that the network parameters tend to convergence and gradually approach the real tag. The experimental analysis shows that the algorithm effectively diagnoses and evaluates the damage degree of the blade structure, and has a high recall rate and accuracy, which proves the effectiveness and robustness of the algorithm.
Remaining Life Prediction for Aircraft Turbine Engines Based on LSTM-RNN - HMM – APPROACH
Authors: Bi Jun-Xi , Fan Wen-Ze , Wang Shou-Bin
Published: February 2021

Prognostics and Health Management (PHM) of the aircraft gas turbine engine is essential in the safety of the aircraft. In this paper, engine remaining useful life (RUL) was predicted with a novel architecture based on a hybrid recurrent neural network. This hybrid model trains HMM firstly and then gives a small LSTM to get distributions of HMM states. These HMM states are further trained to fill in gaps in HMM. Subsequently, a jointly trained hybrid model is constructed, which can enhance stability and accuracy of prediction significantly.
Reliability oriented multi-AGVs online scheduling and path planning problem of automated sorting warehouse system
Authors: Yu N N , Li T K , Wang B L , Yuan S P , Wang Y
Published: February 2021

The automated sorting warehouses are operated by multiple AGVs simultaneously, which can quickly sort a large number of packages. How to solve the problems of multi-AGVs scheduling, path planning and conflict resolution is the key to the reliable and rapid operation of the warehouse system. In order to improve the reliability and sorting efficiency of the system, the objective of this paper is to minimize the maximum handling completion time. Firstly, a multi-AGVs path planning algorithm based on Grid Blocking Degree (GBD) is proposed. This algorithm can plan a conflict-free handling path for each handling task of each AGV, and update the path dynamically according to the real-time traffic congestion. Furthermore, aiming at the comprehensive optimization of scheduling and path planning, a scheduling algorithm based on priority rules is proposed to determine the handling task for AGVs. The data experiments compare the difference of the solution effect of different priority rules, and verify the effectiveness of the algorithm proposed in this paper.
A Method for Thermal Resistance Test of Reverse-Conducting IGBT (RC-IGBT)
Authors: Chen Y , Zhang P , Hu X F , Huang H Z , Lai P , He Z Y , Chen Y Q
Published: February 2021

The RC-IGBT is integrated IGBT and fast recovery diode (FRD) on the same chip. RC-IGBT has smaller size, higher power density, lower cost, and higher reliability. However, due to the snap-back effect, the traditional test circuit and method cannot accurately measure the thermal resistance of RC-IGBT. In this paper, a thermal resistance test circuit based on series compensation of two devices is proposed, and the voltage drop Vec of the body diode is taken as the temperature sensitive parameter of RC-IGBT. The thermal response curve is obtained basing on the change of Vec with temperature. By comparing the traditional method with the new method, it can be seen that the new method can greatly improve the test accuracy.
Reliability analysis of Aeroengine Blades Based on Fourier Transform
Authors: Bi Jun-Xi , Hu Zeng-Lin , Wang Ying , Li Hai-Bin , Wang Shou-Bin
Published: February 2021

As a key part of aero-engine, blade is responsible for energy conversion. This paper summarizes the significance of traditional aero-engine blade reliability analysis. The basic principle of Fourier Transform is introduced. According to the Fourier transform, the decomposition method of the actual dynamic load curve of the blade in the working process in the frequency domain is deduced, and the dynamic load is decomposed in the frequency domain. The specific information of the sinusoidal harmonics which constitute the time domain signal is obtained, and then the theoretical method of restoring it to the time domain is deduced. The Fast Fourier Transform (FFT) is applied to the time domain signal by MATLAB. The dynamic load of aero-engine blade is analyzed by Fourier Transform, and the derivation process of Fourier Transform and inverse transform is completed. Fourier Transform can simulate the actual dynamic load curve of aero-engine blade, which can be used as the theoretical basis for the next step of aero-engine blade reliability test-bed loading.
Research on the Method of Rotary Machinery Fault Diagnosis based on PCA and DBN
Authors: Li H P , Qi Zh L , Hu J P , Zhang X Y
Published: February 2021

Aiming at the difficulty of complex vibration signal transmission path, great influence of different sensor positions on diagnosis results and difficulty in feature extraction of rotary machinery fault diagnosis, a new fault diagnosis method based on Principal Component Analysis (PCA) and Deep Belief Network (DBN) is proposed. The framework of the method is constructed. The theory of PCA and DBN are introduced. And the validity and superiority of the proposed method are verified by the experimental data of typical rotary machinery.
Reliability Evaluation and Optimization for Phased Mission Systems with Cascading Effects
Authors: Ma Chenyang , Zhang Shuai , Zhou Mi , Si Shubin , Cai Zhiqiang
Published: February 2021

The phased mission system (PMS) has been widely used in aerospace, data transmission, internet of things, which perform the entire mission with non-overlapping, consecutive and multiple phases of operation. The challenge for the PMS reliability evaluation is to consider both the dynamic of each component across phases and the functional dependence (FDEP) among components. In some cases, the component can fail individually or resulting from the cascading effect (CE) caused by internal FDEP among components. So, this paper presents the reliability evaluation method for PMSs with the CE based on recursive algorithm. Then, to find the best components’ allocation scheme with the maximized system reliability and the minimized manufacturing cost, the non-dominated sorting genetic algorithm (NSGA-II) is employed to solve the combinatorial optimization problem. Finally, the numerical example illustrates the effectiveness of proposed method and obtains solutions of the optimization model.
Research on the Method of Safety Warning for Shipboard Aircraft Landing
Authors: Fang X T , Zhang K P , Chang Z Z , Peng D
Published: February 2021

In order to ensure the landing safety of the shipboard aircraft, it is necessary to monitor the landing process of the shipboard aircraft, and give an alarm in time for the situation that may endanger the flight safety. This paper mainly studies the use of human (Landing Signal Officer and Flight Crew) and Aircraft Environment Surveillance System (AESS) and compares the defects of these two methods. On this basis, a method of shipboard aircraft landing based on the probability of landing risk is proposed. By comparing the estimated value of landing guidance error with the warning threshold of landing guidance error in the vertical and lateral direction respectively, the warning is determined according to the comparison results.