Adaptive Event-Triggered Time-Varying Output Group Formation Containment Control of Heterogeneous Multiagent Systems

In this paper,a class of time-varying output group formation containment control problem of general linear hetero-geneous multiagent systems(MASs)is investigated under directed topology.The MAS is composed of a number of tracking leaders,formation leaders and followers,where two different types of leaders are used to provide reference trajectories for movement and to achieve certain formations,respectively.Firstly,compen-sators are designed whose states are estimations of tracking lead-ers,based on which,a controller is developed for each formation leader to accomplish the expected formation.Secondly,two event-triggered compensators are proposed for each follower to evalu-ate the state and formation information of the formation leaders in the same group,respectively.Subsequently,a control protocol is designed for each follower,utilizing the output information,to guide the output towards the convex hull generated by the forma-tion leaders within the group.Next,the triggering sequence in this paper is decomposed into two sequences,and the inter-event intervals of these two triggering conditions are provided to rule out the Zeno behavior.Finally,a numerical simulation is intro-duced to confirm the validity of the proposed results.

幼儿园教师保育与教育能力情境判断测验——基于2304名教师的实证研究

保教能力是幼儿园教师专业素养的核心成分,直接影响着幼儿园教育质量和幼儿的学习与发展。本研究通过收集保教实践情境、建立教师反应项、确定评分标准三个步骤初步编制评价工具,辅以随机访谈及1182名教师测评反馈,形成“保育为基、游戏为重”的《幼儿园教师保育与教育能力情境判断测验(初版)》。该评价工具涵盖20个保教实践情境、80个教师反应项以及“最理想”“最不认同做法”“实际首选做法”三类问题作答形式。本研究对来自河北省、上海市、福建省、重庆市四个地区的1122名教师进行正式测评,结果发现该评价工具的信效度及题目质量良好,教师的保教能力与其教龄、职称、受教育水平存在相关;公办园教师的保教能力总体上优于民办园教师;教师普遍存在“知道不应做什么,但不知道应该如何做”的困惑,特别是在游戏与教学情境下。为促进教师保教能力的科学评价与教师保教水平的提升,应关注情境判断测验的开发与运用,提升教师“如何做”的实践智慧。

Recent advances in hydrothermal modification of calcium phosphorus coating on magnesium alloy

Magnesium(Mg) and its alloys have emerged as a favored candidate for bio-regenerative medical implants due to their superior biocompatibility, biodegradability and the elastic modulus close to that of human bone. Unfortunately, the rapid and uncontrollable degradation rate of Mg alloys in chloride-rich body microenvironments limits their clinical orthopedic applications. Recently, Calcium Phosphate(Ca-P)biomaterials, especially Hydroxyapatite(HA), have been broadly applied in the surface functional modification of metal-based biomaterials attributed to their excellent bioactivity and biocompatibility. Hydrothermal modification of Ca-P coatings on Mg alloys has been extensively exploited by researchers for its significant superiorities in controlling coating structure and improving interfacial bonding strength for better osseointegration and corrosion resistance. This work focuses on the up-to-the-minute advances in Ca-P coatings on the surface of Mg and its alloys via hydrothermal methods, including the strategies and mechanisms of hydrothermal modification. Herein, we are inclined to share some feasible and attractive hydrothermal surface modification strategies. From the perspectives of hydrothermal manufacturing technique innovation and coating structure optimization, we evaluate how to foster the corrosion resistance, coating bonding strength, osseointegration and antibacterial properties of Mg alloys with Ca-P coatings synthesized by hydrothermal method. The challenges and future perspectives on the follow-up exploration of Mg alloys for orthopedic applications are also elaborately proposed.

Detection of fusarium head blight using a YOLOv5s-based method improved by attention mechanism

Fusarium head blight (FHB) is one of the most destructive diseases in global wheat production. In order to count the FHB-infected wheat ears under field conditions, this study proposed an algorithm for diseased wheat ear detection based on improved YOLOv5s (Tr-YOLOv5s). The Swin Transformer was used to replace the CSPDarknet backbone network to enhance the extraction of characteristic information of the population wheat ears of FHB in the field background. The convolutional block attention module (CBAM) attention mechanism was added to improve the detection effect of target wheat ears, subsequently improving the overall accuracy of the model. The original loss function complete intersection over union (CIoU) was replaced by Scylla intersection over union (SIoU) loss to accelerate the model convergence and decrease the loss value. The results showed that the mean average precision (mAP) of the Tr-YOLOv5s model reached 90.64%, making a 4.63% improvement compared to the original YOLOv5s model. The improved model could quickly detect and count wheat FHB ear in the field environment, which laid a foundation for the subsequent automatic disease identification and grading of wheat FHB under field conditions.

Luminescence properties of Y2WO6：Yb^3＋/Er^3＋ with enhanced redemission via upconversion

The Er/Ybco-doped Y2 WO6 phosphors were prepared via high temperature solid method for the first time. The structure was investigated with X-ray diffraction(XRD). The crystal morphology was observed through scanning electron microscopy(SEM). Under the excitation of 980 nm diode laser,visible up-conversion(UC) emissions were observed in green and red regions. The luminescence study reveals strong ~4 Sto ~4 Itransition at 545 nm and strong ~4 Fto ~4 Itransition at 657 nm. The relative intensities ratios of red(510-580 nm) to green(640-690 nm) emissions(R) reduce when the samples co-doped with Ybions. The dependence of emission intensity on the pump power indicate that visible UC emissions are governed by two photons, meanwhile three photons process is also involved. For more details, the discussion is made in the energy level diagrams.