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High-speed penetration of ogive-nose projectiles into thick concrete targets:Tests and a projectile nose evolution model

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Defence Technology（防务技术） 2024年第2期32卷 553-571页

作者： xu li yan liu Junbo yan Zhenqing Shi Hongfu Wang Yingliang xu Fenglei Huang State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China Beijing Institute of Technology Chongqing Innovation Center Chongqing401120China China Research and Development Academy of Machinery Equipment Beijing100089China

The majority of the projectiles used in the hypersonic penetration study are solid flat-nosed cylindrical projectiles with a diameter of less than 20 *** study aims to fill the gap in the experimental and analytical study of the evolution of the nose shape of larger hollow projectiles under hypersonic *** the hypersonic penetration test,eight ogive-nose AerMet100 steel projectiles with a diameter of 40 mm were launched to hit concrete targets with impact velocities that ranged from 1351 to 1877 m/*** erosion of the projectiles was observed during high-speed penetration of heterogeneous targets,and apparent localized mushrooming occurred in the front nose of recovered *** examining the damage to projectiles,a linear relationship was found between the relative length reduction rate and the initial kinetic energy of projectiles in different penetration ***,microscopic analysis revealed the forming mechanism of the localized mushrooming phenomenon for eroding penetration,i.e.,material spall erosion abrasion mechanism,material flow and redistribution abrasion mechanism and localized radial upsetting deformation ***,a model of highspeed penetration that included erosion was established on the basis of a model of the evolution of the projectile nose that considers radial upsetting;the model was validated by test data from the literature and the present *** upon the impact velocity,v0,the projectile nose may behave as undistorted,radially distorted or *** to the effects of abrasion of the projectile and enhancement of radial upsetting on the duration and amplitude of the secondary rising segment in the pulse shape of projectile deceleration,the predicted DOP had an upper limit.

关键词： High-speed penetration Concrete target Erosion Projectile nose evolution model

Robust Interval State Estimation for Distribution Systems Considering Pseudo-measurement Interval Prediction

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Journal of Modern Power Systems and Clean Energy 2024年第1期12卷 179-188页

作者： xu Zhang Wei yan Meiqing Huo Hui li the School of Electrical Engineering Chongqing UniversityChongqing 400044China

Interval state estimation(ISE)can estimate state intervals of power systems according to confidence intervals of predicted pseudo-measurements,thereby analyzing the impact of uncertain pseudo-measurements on ***,predicted pseudo-measurements have prediction errors,and their confidence intervals do not necessarily contain the truth values,leading to estimation biases of the *** solve this problem,this paper proposes a pseudo-measurement interval prediction framework based on the Gaussian process regression(GPR)model,thereby improving the prediction accuracy of pseudo-measurement confidence ***,a weight assignment strategy for improving the robustness of weighted least squares(WLS)ISE is *** strategy quantifies the deviation between the pseudo-measurement intervals and their estimated intervals and assigns smaller weights to the pseudo-measurement intervals with larger deviations,thereby improving the estimation accuracy and robustness of the *** paper adopts the data from the supervisory control and data acquisition(SCADA)system of the New York Independent System Operator(NYISO).It verifies the advantages of the GPR method for pseudo-measurement interval prediction by comparing it with the quantile regression and neural network *** addition,this paper demonstrates the effectiveness of the proposed weight assignment strategy through the IEEE 14-bus ***,the differences in the estimation accuracy and the bad data identification between the robust interval state estimation and deterministic state estimation are discussed.

关键词： Interval state estimation interval analysis pseudo-measurement Gaussian process regression(GPR)

Flight Time Minimization of UAV for Cooperative Data Collection in Probabilistic LoS Channel

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China Communications 2024年第2期21卷 210-226页

作者： yan li Shaoyi xu Yunpu Wu Dongji li School of Electronic and Information Engineering Beijing Jiaotong UniversityBeijing 100044China School of Electrical Engineering and Electronic Information Xihua UniversityChengdu 610039China

This paper investigates the data collection in an unmanned aerial vehicle(UAV)-aided Internet of Things(IoT) network, where a UAV is dispatched to collect data from ground sensors in a practical and accurate probabilistic line-of-sight(LoS) channel. Especially, access points(APs) are introduced to collect data from some sensors in the unlicensed band to improve data collection efficiency. We formulate a mixed-integer non-convex optimization problem to minimize the UAV flight time by jointly designing the UAV 3D trajectory and sensors’ scheduling, while ensuring the required amount of data can be collected under the limited UAV energy. To solve this nonconvex problem, we recast the objective problem into a tractable form. Then, the problem is further divided into several sub-problems to solve iteratively, and the successive convex approximation(SCA) scheme is applied to solve each non-convex subproblem. Finally,the bisection search is adopted to speed up the searching for the minimum UAV flight time. Simulation results verify that the UAV flight time can be shortened by the proposed method effectively.

关键词： data collection flight time probabilistic line-of-sight channel unlicensed band unmanned aerial vehicle

家庭同步赋能教育对青中年宫颈癌根治术患者术后病耻感家庭功能及生活质量的影响

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中国妇幼保健 2024年第3期39卷 527-530页

作者：池佳妮应林平李旭艳温州市中心医院妇科浙江温州325000

目的探讨家庭同步赋能教育对青中年宫颈癌患者术后病耻感的影响。方法选取2021年7月—2022年6月在温州市中心医院行宫颈癌根治术治疗的青中年宫颈癌患者88例,根据时间顺序分为对照组(2021年7—12月期间,42例)与研究组(2022年1—6月期... 详细信息

目的探讨家庭同步赋能教育对青中年宫颈癌患者术后病耻感的影响。方法选取2021年7月—2022年6月在温州市中心医院行宫颈癌根治术治疗的青中年宫颈癌患者88例,根据时间顺序分为对照组(2021年7—12月期间,42例)与研究组(2022年1—6月期间,46例)。对照组患者及其家庭成员在术后给予常规健康教育干预,研究组患者及其家庭成员在术后给予家庭同步赋能教育,时间3个月。采用社会影响量表(SIS)、家庭功能评定量表(FAD)、生活质量核心问卷(QLQ-C30)对干预前及干预后6个月时的病耻感、家庭功能及生活质量进行评估。结果两组患者干预前SIS评分比较,差异无统计学意义(P>0.05),干预后评分低于干预前,且研究组低于对照组(P0.05),干预后评分低于干预前,且研究组低于对照组(P0.05),干预后功能领域、症状领域、6种症状评分均低于干预前,且研究组低于对照组,干预后总体健康状况评分高于干预前,且研究组高于对照组(P<0.05)。结论家庭同步赋能教育有助于降低青中年宫颈癌患者术后病耻感,改善家庭功能及提高生活质量。

关键词：家庭同步赋能教育宫颈癌病耻感青中年

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32例Mirizzi综合征的诊治分析

医师在线 2024年第3期14卷 54-56页

作者：吴昆霖季卫奔李延旭吴巍扬州大学医学院扬州大学附属医院肝胆外科江苏扬州225000

目的探讨Mirizzi综合征的临床特点及诊治经验。方法回顾性分析32例Mirizzi综合征患者的临床资料,总结病例的临床症状、影像学特点及诊治经验。结果32例患者中,Ⅰ型患者22例(68.8%),Ⅱ型患者7例(21.9%),Ⅲ型患者2例(6.5%),Ⅳ型患者1例(3.... 详细信息

目的探讨Mirizzi综合征的临床特点及诊治经验。方法回顾性分析32例Mirizzi综合征患者的临床资料,总结病例的临床症状、影像学特点及诊治经验。结果32例患者中,Ⅰ型患者22例(68.8%),Ⅱ型患者7例(21.9%),Ⅲ型患者2例(6.5%),Ⅳ型患者1例(3.2%)。其中,3例患者行ERCP+鼻胆管引流,其余患者均行手术治疗。术后无二次手术患者,均痊愈出院。结论Mirizzi综合征的术前诊断仍较困难,需根据术中具体分型及患者的腹部情况作出相应的治疗方案,从而减少术后并发症,改善患者的预后。

关键词： Mirizzi综合征胆囊结石腹腔镜开腹

Random gradient-free method for online distributed optimization with strongly pseudoconvex cost functions

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Control Theory and Technology 2024年第1期22卷 14-24页

作者： Xiaoxi yan Cheng li Kaihong Lu Hang xu School of Electrical and Information Engineering Jiangsu UniversityZhenjiang212013JiangsuChina College of Electrical Engineering and Automation Shandong University of Science and TechnologyQingdao266590ShandongChina

This paper focuses on the online distributed optimization problem based on multi-agent systems. In this problem, each agent can only access its own cost function and a convex set, and can only exchange local state information with its current neighbors through a time-varying digraph. In addition, the agents do not have access to the information about the current cost functions until decisions are made. Different from most existing works on online distributed optimization, here we consider the case where the cost functions are strongly pseudoconvex and real gradients of the cost functions are not available. To handle this problem, a random gradient-free online distributed algorithm involving the multi-point gradient estimator is proposed. Of particular interest is that under the proposed algorithm, each agent only uses the estimation information of gradients instead of the real gradient information to make decisions. The dynamic regret is employed to measure the proposed algorithm. We prove that if the cumulative deviation of the minimizer sequence grows within a certain rate, then the expectation of dynamic regret increases sublinearly. Finally, a simulation example is given to corroborate the validity of our results.

关键词： Multi-agent system Online distributed optimization Pseudoconvex optimization Random gradient-free method

Spherical Confinement Generates Entropic Force to Accelerate Polymer Chain Detachment

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Chinese Journal of Polymer Science 2024年第3期42卷 407-416,I0010页

作者： Yu-Shan Zheng Jian-Ping Zhou yan xu Kai li Mechanical Engineering Xinjiang UniversityUrumqi 830002China

To understand the dynamic process of polymer detachment, it is necessary to determine the mean detachment time of a single breakable link, which is modeled as a spring. Normally, this time can be viewed as the escape of a Brownian particle from the potential well of the spring. However, as the free dangling length of the polymer chain increases, the conformational entropy of the chain is affected by geometric confinement. It means that the wall exerts a repulsive force on the chain, resulting in accelerated link detachment from a macroscopic perspective. In this work, we investigate the effect of entropy on the detachment rate in the case where the substrate is spherical. We demonstrate that spherical confinement accelerates chain detachment both inside and outside the sphere. An analytical expression for the mean detachment time of breakable links is given, which includes an additional pre-factor that is related to the partition function. Additionally, we analyze the expressions for entropic forces inside the sphere, outside the sphere, and on a flat wall, comparing their magnitudes to explain the difference in mean detachment time.

关键词： Polymer detachment Breakable link Entropic force Mean first passage time

劳动教育融入人体及动物生理学专业课程教学的实践探索

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安徽农业科学 2024年第12期52卷 261-263,267页

作者：李旭艳蒋湘蒲小秋付娜张洪军岭南师范学院广东湛江524048 湛江第一中学广东湛江524048

积极探索劳动教育与专业课程的渗透融合是新时代教学改革的要求,是实现立德树人根本任务的途径之一。人体及动物生理学是生物科学专业的必选课程,充分挖掘课程的劳动教育元素,通过田间劳动、参与式实验课程等方式渗透劳动实践内容,探索... 详细信息

积极探索劳动教育与专业课程的渗透融合是新时代教学改革的要求,是实现立德树人根本任务的途径之一。人体及动物生理学是生物科学专业的必选课程,充分挖掘课程的劳动教育元素,通过田间劳动、参与式实验课程等方式渗透劳动实践内容,探索劳动教育融入专业课程的有效途径,引导学生全面发展。

关键词：专业课程人体及动物生理学劳动教育实践探索

Thermal fatigue and wear of compacted graphite iron brake discs with various thermomechanical properties

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China Foundry 2024年第3期21卷 248-256页

作者： Gui-quan Wang Zhuo xu Zhong-li liu Xiang Chen yan-xiang li School of Nuclear Equipment and Nuclear Engineering Yantai UniversityYantai 264005ShandongChina School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China Key Laboratory for Advanced Materials Processing Technology Ministry of EducationBeijing 100084China

The increase in payload capacity of trucks has heightened the demand for cost-effective yet high performance brake *** this work,the thermal fatigue and wear of compacted graphite iron brake discs were investigated,aiming to provide an experimental foundation for achieving a balance between their thermal and mechanical *** graphite iron brake discs with different tensile strengths,macrohardnesses,specific heat capacities and thermal diffusion coefficients were produced by changing the proportion and strength of *** peak temperature,pressure load and friction coefficient of compacted graphite iron brake discs were analyzed through inertia friction *** morphology of thermal cracks and 3D profiles of the worn surfaces were also *** is found that the thermal fatigue of compacted graphite iron discs is determined by their thermal properties.A compacted graphite iron with the highest specific heat capacity and thermal diffusion coefficient exhibits optimal thermal fatigue *** of the matrix at low temperatures significantly weakens the function of alloy strengthening in hindering the propagation of thermal *** the reduced hardness,increasing the ferrite proportion can mitigate wear loss resulting from low disc temperatures and the absence of abrasive wear.

关键词： compacted graphite iron brake disc thermomechanical properties thermal fatigue wear