Retraction: Pu Zhang, Research on intelligent elevation control method of shearer drum based on deep learning, IET Software 2023 (https://doi.org/10.1049/sfw2.12089).
The above article from IET ...Software, published online on 17 January 2023 in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the Editor‐in‐Chief, Hana Chockler, the Institution of Engineering and Technology (the IET) and John Wiley and Sons Ltd. This article was published as part of a Guest Edited special issue. Following an investigation, the IET and the journal have determined that the article was not reviewed in line with the journal’s peer review standards and there is evidence that the peer review process of the special issue underwent systematic manipulation. Accordingly, we cannot vouch for the integrity or reliability of the content. As such we have taken the decision to retract the article. The authors have been informed of the decision to retract.
This paper addressed a well-documented open problem regarding multiple unmanned aerial vehicles (multi-UAVs) formation keeping. A cooperative guidance control method based on the back-stepping ...approach is proposed to rapidly form the desired formation and reach the multi-UAV steady state. The UAV formation system consists of four UAVs, forming a regular triangle formation. One of the UAVs is a virtual leader and is located at the center of the triangle; the other three UAVs are located at the vertices of the triangle. The forward speed of leader is used as the forward direction of the formation, and the followers follow the leader in a formation flight. The error dynamics model of each follower is established by using the leader guidance mechanism, and the communication mode between any two UAVs is established based on graph theory. In addition, the guidance control law is obtained via the back-stepping approach. We reasonably construct the Lyapunov function to prove the stability of the proposed cooperative guidance control law in formation aggregation and keeping. Moreover, the proposed method is compared with the model prediction method (MPC) and the Lyapunov method to further verify the effectiveness of the proposed method. The simulation results show that each UAV can converge to the desired motion trajectory and fly in the desired formation with fast convergence speed and small steady-state error.
Herein, by directly using Watson–Crick base pairing, a highly ordered and field-free three-dimensional (3D) DNA nanostructure is self-assembled by azobenzene (azo)-functionalized DNA nippers in a few ...minutes, which was applied as a 3D DNA nanomachine with an improved movement efficiency compared to traditional Au-based 3D nanomachines due to the organized and high local concentration of nippers on homogeneous DNA nanostructure. Once microRNA (miRNA) interacts with the 3D nanomachine, the nippers “open” to hybridize with the miRNA. Impressively, photoisomerization of the azo group induces dehybridization/hybridization of the nippers and miRNA under irradiation at different wavelengths, which easily solves one main technical challenge of DNA nanotechnology and biosensing: reversible locomotion in one step within 10 min. As a proof of concept, the described 3D machine is successfully applied in the rapid single-step detection of a biomarker, which gives impetus to the design of new generations of mechanical devices beyond the traditional ones with ultimate applications in sensing analysis and diagnostic technologies.
Enantiomers of 2, 6‐diaminotriptycene (R, R‐1 and S, S‐1) are split by chiral‐phase HPLC and their absolute configurations are identified by single‐crystal X‐ray diffraction technology. Using the ...enantiomers as monomers, a couple of chiral porous polyimides (R‐FTPI and S‐FTPI) are prepared by polycondensation reactions and display good heat stability, high BET surface area and good solubility in organic solvents. Moreover, both of R‐FTPI and S‐FTPI can be cast into robust, free‐standing films suitable for enantioselective separation with symmetrical chiral selectivity.
Chiral porous polyimides (FTPI) were synthesized using monomers of chiral 2,6‐diaminotriptycene. The absolute configurations were identified by single‐crystal X‐ray diffraction. The obtained R‐FTPI and S‐FTPI can be cast into robust, free‐standing films suitable for enantioselective separation with high permeation rates.
Herein, a dual microRNA (miRNA) powered bi-directional DNA walking machine with precise control was developed to fabricate an enzyme-free biosensor on the basis of distance-based ...electrochemiluminescence (ECL) energy transfer for multiple detection of miRNAs. By using miRNA-21 as the driving force, the DNA walker could move forth along the track and generated quenching of ECL response due to the proximity between Au nanoparticles (AuNPs) and Mn2+ doped CdS nanocrystals (CdS:Mn NCs) film as the ECL emitters, realizing ultrasensitive determination of miRNA-21. Impressively, once miRNA-155 was introduced as the driving force, the walker could move back along the track automatically, and surface plasmon resonance (SPR) occurred owing to the appropriate large separation between AuNPs and CdS:Mn NCs, achieving an ECL enhancement and realizing ultrasensitive detection of miRNA-155. The bi-directional movement of the DNA walker on the track led to continuous distance-based energy transfer from CdS:Mn NCs film by AuNPs, which resulted in significant ECL signal variation of CdS:Mn NCs for multiple detection of miRNA-21 and miRNA-155 down to 1.51 fM and 1.67 fM, respectively. Amazingly, the elaborated biosensor provided a new chance for constructing controllable molecular nanomachines in biosensing, disease diagnosis, and clinical analysis.
An outbreak of the 2019 novel coronavirus (COVID-19) has been ongoing in China since January 2020. The threat of infection affects the work and life of most of the population and may also damage ...sleep. This study aims to examine the subjective sleep status and mental health of the population during the peak of the COVID-19 epidemic.
The data were collected through an online questionnaire with a sample of 5461 individuals in China from February 5, 2020, to February 23, 2020. Participants were divided into four groups based on their degree of threat from COVID-19: Group 1 was most closely associated with COVID-19, including inpatients diagnosed with COVID-19, first-line hospital workers and first-line management staff; Group 2 included outpatients diagnosed with COVID-19 and patients who developed a fever and visited the hospital; Group 3 included people related to Group 1 or 2, such as their colleagues, relatives, friends and rescuers; and Group 4 was the farthest removed from contact with COVID-19, covering the general public affected by COVID-19 prevention strategies. The Insomnia Severity Index (ISI), Patient Health Questionnaire (PHQ-9), Generalized Anxiety Disorder Scale (GAD-7) and Acute Stress Disorder Scale (ASDS) were used.
Threat degree of COVID-19 (groups) had significant correlations with insomnia, depression, anxiety, and stress (p < 0.05, p < 0.01). Age, gender, and area (Hubei province or other provinces) had significant correlations with insomnia (p < 0.01). A total of 1380 (24.46%) participants were suspected of having major depression based on the PHQ-9. Additionally, 1042 (18.47%) participants were suspected of having generalized anxiety disorder based on the GAD-7. A total of 892 (15.8%) of the participants had Acute Stress Disorder (ASD) according to the ASDS. The prevalence of clinical insomnia during the outbreak was 20.05% (1131) according to the ISI. The factors of satisfaction with the current sleep pattern and how perceptible the symptoms of the current sleep pattern are to other people (p < 0.05) and the middle (difficulty staying asleep) and terminal (waking up too early) (p < 0.01) factors of the ISI were significantly different across groups. A total of 1129 (20.01%) participants spent more than one hour awake in bed.
The results indicated that insomnia is more severe in people who are female, young, living in the epicenter and experiencing a high degree of threat from COVID-19. As prevention and treatment efforts continue with regard to COVID-19, the general public has developed poor sleep hygiene habits, which deserve attention.
•It reported the immediate impact of sleep status of a large sample at the peak of the COVID-19 spread in China.•Reports on sleep habits of individuals in China by different degrees of COVID-19 threat.•The threat degree of COVID-19 is associated with the prevalence of anxiety, depression and acute stress disorder.•The general public has developed poor sleep hygiene habits which deserve attention.
The representations of a quiver Q over a field k (the kQ-modules, where kQ is the path algebra of Q over k) have been studied for a long time, and one knows quite well the structure of the module ...category modkQ. It seems to be worthwhile to consider also representations of Q over arbitrary finite-dimensional k-algebras A. Here we draw the attention to the case when A=kϵ is the algebra of dual numbers (the factor algebra of the polynomial ring kT in one variable T modulo the ideal generated by T2), thus to the Λ-modules, where Λ=kQϵ=kQT/〈T2〉. The algebra Λ is a 1-Gorenstein algebra, thus the torsionless Λ-modules are known to be of special interest (as the Gorenstein-projective or maximal Cohen–Macaulay modules). They form a Frobenius category L, thus the corresponding stable category L_ is a triangulated category. As we will see, the category L is the category of perfect differential kQ-modules and L_ is the corresponding homotopy category. The category L_ is triangle equivalent to the orbit category of the derived category Db(modkQ) modulo the shift and the homology functor H:modΛ→modkQ yields a bijection between the indecomposables in L_ and those in modkQ. Our main interest lies in the inverse, it is given by the minimal L-approximation. Also, we will determine the kernel of the restriction of the functor H to L and describe the Auslander–Reiten quivers of L and L_.
Abstract
Electrochemical synthesis of H
2
O
2
through a selective two-electron (2e
−
) oxygen reduction reaction (ORR) is an attractive alternative to the industrial anthraquinone oxidation method, ...as it allows decentralized H
2
O
2
production. Herein, we report that the synergistic interaction between partially oxidized palladium (Pd
δ+
) and oxygen-functionalized carbon can promote 2e
−
ORR in acidic electrolytes. An electrocatalyst synthesized by solution deposition of amorphous Pd
δ+
clusters (Pd
3
δ+
and Pd
4
δ+
) onto mildly oxidized carbon nanotubes (Pd
δ+
-OCNT) shows nearly 100% selectivity toward H
2
O
2
and a positive shift of ORR onset potential by ~320 mV compared with the OCNT substrate. A high mass activity (1.946 A mg
−1
at 0.45 V) of Pd
δ+
-OCNT is achieved. Extended X-ray absorption fine structure characterization and density functional theory calculations suggest that the interaction between Pd clusters and the nearby oxygen-containing functional groups is key for the high selectivity and activity for 2e
−
ORR.
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•Sulfur-containing covalent organic framework (S-COF) was synthetized by post-modification strategy.•COF-supported Au NPs (Au-S-COF) has narrow size distribution (4.2 ± 1.2 nm) and ...high distribution density.•Au-S-COF exhibits excellent heterogeneous catalytic activity, stability and recyclability.
Post-modification strategy was used to synthesize sulfur-containing covalent organic framework (S-COF) by thiol-ene “click” reaction from a propenyl-functionalized COF (A-COF). Furthermore, the obtained S-COF was used as matrix to successfully prepare COF-supported Au NPs (Au-S-COF) with narrow size distribution (4.2 ± 1.2 nm) and high distribution density, which shows excellent catalytic activities in reduction of 4-nitrophenol with remarkable stability and recyclability. In the Au-S-COF heterogeneous catalytic system, the strong anchoring ability between Au NPs and sulfur-containing groups over COF’s surface enhance the binding of Au NPs with COFs to maintain the dispersity of NPs and their catalytic activity for long-term performance.
We clarify the relation between the subcategory D_（hf）~b（A） of homological finite objects in D~b（A）and the subcategory K~b（P） of perfect complexes in D~b（A）, by giving two classes of abelian ...categories A with enough projective objects such that D_（hf）~b（A） = K~b（P）, and finding an example such that D_（hf）~b（A）≠K~b（P）. We realize the bounded derived category D~b（A） as a Verdier quotient of the relative derived category D_C~b（A）, where C is an arbitrary resolving contravariantly finite subcategory of A. Using this relative derived categories, we get categorical resolutions of a class of bounded derived categories of module categories of infinite global dimension.We prove that if an Artin algebra A of infinite global dimension has a module T with inj.dimT 〈∞ such that ~⊥T is finite, then D~b（modA） admits a categorical resolution; and that for a CM（Cohen-Macaulay）-finite Gorenstein algebra, such a categorical resolution is weakly crepant.
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