Study on the coupling calculation method for the launch dynamics of a self-propelled artillery multibody system considering engraving process

The launch dynamics theory for multibody systems emerges as an innovative and efficacious approach for the study of launch dynamics,capable of addressing the challenges of complex modeling,diminished computational efficiency,and imprecise analyses of system dynamic responses found in the dynamics research of intricate multi-rigid-flexible body systems,such as self-propelled artillery.This advancement aims to enhance the firing accuracy and launch safety of self-propelled artillery.Recognizing the shortfall of overlooking the band engraving process in existing theories,this study introduces a novel coupling calculation methodology for the launch dynamics of a self-propelled artillery multibody system.This method leverages the ABAQUS subroutine interface VUAMP to compute the dynamic response of the projectile and barrel during the launch process of large-caliber self-propelled artillery.Additionally,it examines the changes in projectile resistance and band deformation in relation to projectile motion throughout the band engraving process.Comparative analysis of the computational outcomes with experimental data evidences that the proposed method offers a more precise depiction of the launch process of self-propelled artillery,thereby enhancing the accuracy of launch dynamics calculations for self-propelled artillery.

Continuous Sign Language Recognition Based on Spatial-Temporal Graph Attention Network

Continuous sign language recognition(CSLR)is challenging due to the complexity of video background,hand gesture variability,and temporal modeling difficulties.This work proposes a CSLR method based on a spatialtemporal graph attention network to focus on essential features of video series.The method considers local details of sign language movements by taking the information on joints and bones as inputs and constructing a spatialtemporal graph to reflect inter-frame relevance and physical connections between nodes.The graph-based multihead attention mechanism is utilized with adjacent matrix calculation for better local-feature exploration,and short-term motion correlation modeling is completed via a temporal convolutional network.We adopted BLSTM to learn the long-termdependence and connectionist temporal classification to align the word-level sequences.The proposed method achieves competitive results regarding word error rates(1.59%)on the Chinese Sign Language dataset and the mean Jaccard Index(65.78%)on the ChaLearn LAP Continuous Gesture Dataset.

Combining Genome Wide Association Studies and Differential Gene Expression Data Analyses Identifies Candidate Genes Affecting Mastitis Caused by Two Different Pathogens in the Dairy Cow

Mastitis is a costly disease which hampers the dairy industry. Inflammation of the mammary gland is commonly caused by bacterial infection, mainly Escherichia coli, Streptococcus uberis and Staphylococcus aureus. As more bacteria become multi-drug resistant, one potential approach to reduce the disease incidence rate is to breed selectively for the most appropriate and potentially protective innate immune response. The genetic contribution to effective disease resistance is, however, difficult to identify due to the complex interactions that occur. In the present study two published datasets were searched for common differentially expressed genes (DEGs) with similar changes in expression in mammary tissue following intra-mammary challenge with either E. coli or S. uberis. Additionally, the results of seven published genome-wide association studies (GWAS) on different dairy cow populations were used to compile a list of SNPs associated with somatic cell count. All genes located within 2 Mbp of significant SNPs were retrieved from the Ensembl database, based on the UMD3.1 assembly. A final list of 48 candidate genes with a role in the innate immune response identified from both the DEG and GWAS studies was further analyzed using Ingenuity Pathway Analysis. The main signalling pathways highlighted in the response of the bovine mammary gland to both bacterial infections were 1) granulocyte adhesion and diapedesis, 2) ephrin receptor signalling, 3) RhoA signalling and 4) LPS/IL1 mediated inhibition of RXR function. These pathways comprised a network regulating the activity of leukocytes, especially neutrophils, during mammary gland inflammation. The timely and properly controlled movement of leukocytes to infection loci seems particularly important in achieving a good balance between pathogen elimination and excessive tissue damage. These results suggest that polymorphisms in key genes in these pathways such as SELP, SELL, BCAR1, ACTR3, CXCL2, CXCL6, CXCL8 and FABP may influence the ability of dairy cows to resist mastitis.

Association between Single Nucleotide Polymorphism in RelA with Somatic Cell Count and Longevity Supports Importance of NF-κB Signalling in Cattle Health

Mastitis reduces milk production and causes culling. The NF-κB transcription factor RelA plays a central regulatory role in innate immunity. This study used a candidate gene approach to investigate associations between the synonymous C/G SNP rs48035703 in RELA with somatic cell count (SCC) and survival time. Blood samples were collected from 337 Holstein-Friesian heifers on 19 farms and genotyped by PCR-restriction fragment length polymorphism. Animals were monitored from 6 months until 2340 d of age. Pedigree, milk production and disease records were obtained. Genotype frequencies were CC 0.63, CG 0.30 and GG 0.06. The C allele had a favourable additive effect on survival: average longevities from birth were CC, 1872 d;CG, 1745 d and GG 1596 d (P < 0.003). Log transformed first lactation somatic cell count (SCC)data showed a significant association with this SNP using an allele substitution model (mean residuals ± SD: GG 0.30 ± 1.263;CG 0.22 ± 0.994, CC -0.04 ± 0.803, P < 0.05). More CC cows than expected were classified as intermediate and fewer as mastitic (30.4% v 45.9%) with respect to SCC class when categorised as 0 (unaffected), 1 (intermediate) and 2 (mastitic), whereas for CG heterozygotes fewer were intermediate and more were mastitic (12.1% v 60.3%) (p = 0.05). RELA rs48035703 CC genotype cows were therefore less likely to experience a high SCC and survived longer. These results support a role for RelA in combating mammary gland infection and warrant further studies in additional populations.

A theoretical investigation of glide dislocations in BN/AlN heterojunctions

Glide dislocations with periodic pentagon-heptagon pairs are investigated within the theory of one-dimensional misfit dislocations in the framework of an improved Peierls–Nabarro(P–N)equation in which the lattice discreteness is fully considered.We find an approximate solution to handle misfit dislocations,where the second-order derivative appears in the improved P–N equation.This result is practical for periodic glide dislocations with narrow width,and those in the BN/AlN heterojunction are studied.The structure of the misfit dislocations and adhesion work are obtained explicitly and verified by first-principles calculations.Compared with shuffle dislocations,the compression force in the tangential direction of glide dislocations has a greater impact on the normal direction,and the contributions of the normal displacement to the interfacial energy cannot simply be ignored.

Modification of the Peierls-Nabarro model for misfit dislocation

For a misfit dislocation,the balance equations satisfied by the displacement fields are modified,and an extra term proportional to the second-order derivative appears in the resulting misfit equation compared with the equation derived by Yao et al.This second-order derivative describes the lattice discreteness effect that arises from the surface effect.The core structure of a misfit dislocation and the change in interfacial spacing that it induces are investigated theoretically in the framework of an improved Peierls-Nabarro equation in which the effect of discreteness is fully taken into account.As an application,the structure of the misfit dislocation for a honeycomb structure in a two-dimensional heterostructure is presented.

Automatic Construction Method for Domain Concepts Based on Wikipedia Semantic Knowledge Base

This paper proposes a method to construct conceptual semantic knowledge base of software engineering domain based on Wikipedia. First, it takes the concept of SWEBOK V3 as the standard to extract the interpretation of the concept from the Wikipedia, and extracts the keywords as the concept of semantic;Second, through the conceptual semantic knowledge base, it is formed by the relationship between the hierarchical relationship concept and the other text interpretation concept in the Wikipedia. Finally, the semantic similarity between concepts is calculated by the random walk algorithm for the construction of the conceptual semantic knowledge base. The semantic similarity of knowledge base constructed by this method can reach more than 84%, and the effectiveness of the proposed method is verified.

Preoperative Prediction of Lymph Node Metastasis in Colorectal Cancer with Deep Learning

Objective.To develop an artificial intelligence method predicting lymph node metastasis(LNM)for patients with colorectal cancer(CRC).Impact Statement.A novel interpretable multimodal AI-based method to predict LNM for CRC patients by integrating information of pathological images and serum tumor-specific biomarkers.Introduction.Preoperative diagnosis of LNM is essential in treatment planning for CRC patients.Existing radiology imaging and genomic tests approaches are either unreliable or too costly.Methods.A total of 1338 patients were recruited,where 1128 patients from one centre were included as the discovery cohort and 210 patients from other two centres were involved as the external validation cohort.We developed a Multimodal Multiple Instance Learning(MMIL)model to learn latent features from pathological images and then jointly integrated the clinical biomarker features for predicting LNM status.The heatmaps of the obtained MMIL model were generated for model interpretation.Results.The MMIL model outperformed preoperative radiology-imaging diagnosis and yielded high area under the curve(AUCs)of 0.926,0.878,0.809,and 0.857 for patients with stage T1,T2,T3,and T4 CRC,on the discovery cohort.On the external cohort,it obtained AUCs of 0.855,0.832,0.691,and 0.792,respectively(T1-T4),which indicates its prediction accuracy and potential adaptability among multiple centres.Conclusion.The MMIL model showed the potential in the early diagnosis of LNM by referring to pathological images and tumor-specific biomarkers,which is easily accessed in different institutes.We revealed the histomorphologic features determining the LNM prediction indicating the model ability to learn informative latent features.

High energy storage density in NaNbO_(3) antiferroelectrics with double hysteresis loop

Antiferroelectrics(AFEs)possess great potential for high performance dielectric capacitors,due to their distinct double hysteresis loop with high maximum polarization and low remnant polarization.However,the well-known NaNbO_(3) lead-free antiferroelectric(AFE)ceramic usually exhibits square-like P–E loop related to the irreversible AFE P phase to ferroelectric(FE)Q phase transition,yielding low recoverable energy storage density(Wrec).Herein,significantly improved Wrec up to 3.3 J/cm^(3) with good energy storage efficiency(η)of 42.4% was achieved in Na_(0.7)Ag_(0.3)Nb_(0.7)Ta_(0.3)O_(3)(30Agsingle bond30Ta)ceramic with well-defined double P–E loop,by tailoring the A-site electronegativity with Ag+and B-site polarizability with Ta^(5+).The Transmission Electron Microscope,Piezoresponse Force Microscope and in-situ Raman spectra results verified a good reversibility between AFE P phase and high-field-induced FE Q phase.The improved stability of AFE P phase,being responsible for the double P–E loop and improved Wrec,was attributed to the decreased octahedral tilting angles and cation displacements.This mechanism was revealed by synchrotron X-ray diffraction and Scanning Transmission Electron microscope.This work provides a good paradigm for achieving double P–E loop and high energy storage density in NaNbO_(3)-based ceramics.

钙钛矿织构陶瓷的前瞻观点

Piezoelectric materials are the core components in transducers and sensors within numerous electromechanical applications because of their ability to convert mechanical and electrical signals into each other [1]. Since piezoelectric materials govern the bandwidth, sensitivity, and energy conversion efficiency of the transducers, enhancing their electromechanical coupling factors emerges as a top priority to optimize the overall performance of piezoelectric applications. Among various piezoelectric materials.

Lead-free piezoceramic macro-fiber composite actuators toward active vibration control systems

Macro-fiber composite actuators(MFCAs)suffer from strict restrictions on the utilization of lead-containing precursors due to growing environmental concerns.To address this issue,a novel lead-free MFCA based on potassium sodium niobate piezoceramics has been developed using the dice&fill method.The MFCA demonstrates large electric field-induced displacement(31.4μm over-500-1500 V at 0.5 Hz),excellent frequency stability,and a strong linear relationship between the induced displacement and the external voltage amplitude.Meanwhile,unlike lead-based MFCA that requires superposition of a negative dc bias voltage to pursue higher output performance but risks depolarization,lead-free MFCA can achieve larger displacement by superimposing only a positive bias voltage.This device exhibits excellent reliability,maintaining a stable output over 10^(5) electrical cycles.Additionally,a“back-to-back”coupled MFCA has been developed to regulate bidirectional displacement,making it suitable for various practical applications,including active vibration control.This approach has resulted in a 90%vibration reduction and provides new insights into the design of MFCAs,further facilitating their application in active vibration control systems.

Coverage of 13-Valent Pneumococcal Conjugate Vaccine Among Children 0–15 Months of Age—9 Provinces,China,2019–2021

Summary What is already known on this topic?Limited data exist regarding the coverage of the 13-valent pneumococcal conjugate vaccine(PCV13)in China.A lack of official statistics,coupled with an insufficient body of published literature,hinders the accurate depiction of the current situation.What is added by this report?This study investigated the utilization of PCV13 and estimated its coverage in nine provinces across eastern,central,and western China between 2019 and 2021.Despite an annual increase in PCV13 usage during this period,the overall coverage remained suboptimal.

Study on the Vibration Reduction Characteristics of FWMAV Flexible Bionic Wings Mimicking the Hindwings of Trypoxylus dichotomus

Using the method of structural finite element topology optimization and analysis of the hindwings of Trypoxylus dichotomus,this work identified the main loading force transmission path and designed the initial structure of a bionic flexible wing.A structural design scheme of the vibration damping unit was proposed,and the structural mechanics and modal vibration characteristics were simulated and analyzed.3D printing technology was used to manufacture the designed bionic wing skeleton,which was combined with two kinds of wing membrane materials.The Flapping Wing Micro-aerial Vehicle(FWMAV)transmission mechanism vibration characteristics were observed and analyzed by a high-speed digital camera.A triaxial force transducer was used to record the force vibration of the flexible bionic wing flapping in a wind tunnel.A wavelet processing method was used to process and analyze the force signal.The results showed that the force amplitude was more stable,the waveform roughness was the lowest,and the peak shaving phenomenon at the z-axis was the least obvious for the bionic flexible wing model that combined the topology-optimized bionic wing skeleton with a polyamide elastic membrane.This was determined to be the most suitable design scheme for the wings of FWMAVs.

Biomimeitc Design of a Stubble-Cutting Disc Using Finite Element Analysis

Mole rat （Scaptochirus moschatus）, a soil-burrowing mammal, can efficiently dig soil using its fore claws. The profile curves of its claw toe provide excellent structure for digging. In this paper, a biomimetic stubble-cutting disc was designed by learning from the geometrical characteristics of the mole rat claw toes. To compare the structural strength and working eff^- ciency of the biomimetic disc and the conventional stubble-cutting disc, three-dimensional （3D） models of the discs were built and numerical analyzed in ABAQUS. In the dynamic soil cutting model, soil was modeled as an elastic-plastic material with elastic parameters, including Young＇s modulus, Poisson＇s ratio and Drucker-Prager criterion, which were obtained from triaxial tests. A general contact algorithm was used to simulate the interaction between rotary disc and soil. In FEA models, for the combined action of normal and friction stresses, the stress on the biomimetic disc is 34.33% lower than that of the conventional disc. For only the normal stress, the stress on the biomimetic disc is 22.64% lower than that on the conventional one. The magnitude of soil stress in biomimetie disc cutting model is 6.87% higher than that in conventional disc. The FEA results indicate that the biomimetic disc performs better in structural strength and cutting efficiency.

Bio-inspirations for the Development of Light Materials based on the Nanomechanical Properties and Microstructures of Beetle Dynastes tityus

Dynastes tityus(D.tityus)is a typical beetle whose elytra are light and strong.The primary function of elytra is to protect beetle's hindwings.In this paper,D.tityus elytra were selected as the biological prototype for the investigation to obtain bio-inspirations for the design and development of light materials with high ratio of strength to mass.Firstly,the microstructure investigation and quasi-static nanoindentation tests have been carried out on the ten samples of the selected elytra ofD.tityus to reveal their mechanical properties and microstructures.Secondly,based on the fmdings from the microstructure investigation and nanoindentation tests,three models of bio-inspired materials have been proposed for further study to gain the deep understanding of the relationships between the special mechanical characteristics and microstructures.Then Finite Element Analysis(FEA)simulations have been performed on the three models for harvesting the bio-inspirations for the initial design of light materials.Finally,through comparative analysis of the findings from the microstructure investigation,the nanoindentation tests and the simulations,some meaningful bio-inspirations have been reaped for the future optimization of the design and development of light materials with high ratio of strength to mass.

Ce and W co-doped CaBi_(2)Nb_(2)O_(9) with enhanced piezoelectric constant and electrical resistivity at high temperature

Ce and W co-doped CaBi_(2)Nb_(2)O_(9) ceramics with chemical formula Ca_(0.96)Ce_(0.04)Bi_(2)Nb_(2-x)W_(x)O_(9)(CCBNW100x,x=0-0.07)are fabricated via conventional solid state sintering method,to investigate the effect of W addition on the structure,electrical resistivity,dielectric and piezoelectric properties.A piezoelectric constant d33 of 13.4 pC/N is obtained in CCBN-W2 ceramics,>100% higher than that of pure CaBi_(2)Nb_(2)O_(9)(d_(33)=5.8e6.4 pC/N).Of particular significance is that the electrical resistivity of CCBN-W2 ceramics(r=3.7×109 U cm at 500℃)is three orders of magnitude higher than pure CaBi_(2)Nb_(2)O_(9)(r=2.9×10^(6) U cm at same temperature).All these properties,together with its low dielectric loss(tandδ0.13%)and excellent d33 thermal stability up to 800℃,merit the CCBN-W2 ceramics for high temperature piezoelectric sensing applications.

Lead-free textured piezoceramics using tape casting:A review

In this review,the evolution of textured lead-free piezoceramics has been explored,primarily focusing on the technique of templated grain growth(TGG)and reactive-templated grain growth(RTGG),as an alternative to single crystals.The mechanics and properties of using template in guiding and orienting the ceramic grains into the same crystal orientation allow for piezoelectric properties approaching those of their single-crystal counterparts.The fabrication process was surveyed in depth,with focus placed on the tape casting process and numerous variables associated with aligning the template seeds in the ceramic matrix.The piezoelectric and ferroelectric properties of the textured ceramics are supposed to be a function of all parameters(tape casting,slurry formation,sintering profile,template properties)in an effort to determine the significance of their contributions to the properties.

Implantable nerve guidance conduits:Material combinations,multi-functional strategies and advanced engineering innovations

Nerve guidance conduits(NGCs)have attracted much attention due to their great necessity and applicability in clinical use for the peripheral nerve repair.Great efforts in recent years have been devoted to the development of high-performance NGCs using various materials and strategies.The present review provides a comprehensive overview of progress in the material innovation,structural design,advanced engineering technologies and multi functionalization of state-of-the-art nerve guidance conduits NGCs.Abundant advanced engineering technologies including extrusion-based system,laser-based system,and novel textile forming techniques in terms of weaving,knitting,braiding,and electrospinning techniques were also analyzed in detail.Findings arising from this review indicate that the structural mimetic NGCs combined with natural and synthetic materials using advanced manufacturing technologies can make full use of their complementary advantages,acquiring better biomechanical properties,chemical stability and biocompatibility.Finally,the existing challenges and future opportunities of NGCs were put forward aiming for further research and applications of NGCs.

(Bi_(0.51)Na_(0.47))TiO_(3) based lead free ceramics with high energy density and efficiency

Dielectric ceramics with high energy storage density and energy efficiency play an important role in high power energy storage applications.In this work,lead free relaxor ferroelectric ceramics in (1-x) Bi_(0.51)Na_(0.47)TiO_(3-x)Ba(Zr_(0.3)Ti_(0.7))O_(3)(BNT-BZT100x:x=0.20,0.30,0.40 and 0.50)system are fabricated by conventional solid-state sintering method.The BNT-BZT100x ceramics are sintered dense with minimal pores,exhibiting pseudocubic symmetry and strong relaxor characteristic.A high energy storage density of 3.1 J/cm^(3) and high energy efficiency of 91% are simultaneously achieved in BNT-BZT40 ceramic with 0.1mm in thickness,at the applied electric field of 280 kV/cm.The temperature stability of the energy density is studied over temperature range of 20-160℃ ,showing minimal variation below 1.5%,together with the excellent cycling reliability(the variations of both energy density and efficiency are below 3% up to 106 cycles),making BNT-BZT40 ceramic promising candidate for high-temperature dielectric and energy storage applications.

Review and Classification of Bio-inspired Algorithms and Their Applications

Scientists have long looked to nature and biology in order to understand and model solutions for complex real-world problems.The study of bionics bridges the functions,biological structures and functions and organizational principles found in nature with our modem technologies,numerous mathematical and metaheuristic algorithms have been developed along with the knowledge transferring process from the lifeforms to the human technologies.Output of bionics study includes not only physical products,but also various optimization computation methods that can be applied in different areas.Related algorithms can broadly be divided into four groups:evolutionary based bio-inspired algorithms,swarm intelligence-based bio-inspired algorithms,ecology-based bio-inspired algorithms and multi-objective bio-inspired algorithms.Bio-inspired algorithms such as neural network,ant colony algorithms,particle swarm optimization and others have been applied in almost every area of science,engineering and business management with a dramatic increase of number of relevant publications.This paper provides a systematic,pragmatic and comprehensive review of the latest developments in evolutionary based bio-inspired algorithms,swarm intelligence based bio-inspired algorithms,ecology based bio-inspired algorithms and multi-objective bio-inspired algorithms.