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数学进展 2024年第5期53卷 974-982页

作者：杨博胡立群南昌大学数学与计算机学院江西南昌330031

本文证明了每一对充分大且满足某些必要条件的奇数可以表示为一个素数、四个素数的立方与128个2的方幂之和.

关键词：圆法 Goldbach-Linnik问题 2的方幂

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EAST托卡马克中子与伽马在线监测研究

核科学与工程 2024年第3期44卷 711-721页

作者：李成勋霍志鹏钟国强胡立群中国科学技术大学安徽合肥230026 中国科学院合肥物质科学研究院安徽合肥230031

为了实现对实验型先进全超导托卡马克(Experimental Advanced Superconducting Tokamak,EAST)装置聚变产物中子与射线的有效监测,建立了一套核辐射在线监测系统。在装置大厅内外区域共布置13个监测点,根据装置大厅内外辐射强度的差异,... 详细信息

为了实现对实验型先进全超导托卡马克(Experimental Advanced Superconducting Tokamak,EAST)装置聚变产物中子与射线的有效监测,建立了一套核辐射在线监测系统。在装置大厅内外区域共布置13个监测点,根据装置大厅内外辐射强度的差异,分别采用探测范围广、时间响应快和探测灵敏度高、工作稳定性强相结合的BF3正比计数管和氩气电离室。脉冲信号经前置放大器、运算放大器、脉冲甄别与成形后送入单片机处理,通过双绞线与以太网的混合组网方式将数据传输到采集机,利用LabVIEW采集软件实现对中子与射线实时剂量率及累积剂量的采集与存储。监测数据表明,放电时大厅内中子和射线剂量率在短时间快速升高,且距离主机越近剂量率越大。而大厅外辐射剂量率始终处于极低水平,几乎不受脉冲放电的影响。该监测系统满足了EAST托卡马克装置辐射监测需求,确保了人员与周围环境辐射安全,保障了聚变装置安全有效运行。

关键词： EAST 核辐射中子射线监测系统

微弧氧化钛电泳沉积制备氧化镁涂层及其抗菌性与生物相容性

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中国表面工程 2024年第2期37卷 211-219页

作者：范鑫丽杜佳恒肖东琴李耀华胡丽群贺葵翁杰段可刘刚利山东大学口腔医院口腔颌面外科济南250012 南充市中心医院组织工程与干细胞研究所南充637000 西南医科大学附属医院骨与关节外科泸州646000 西南交通大学医学院成都610031

口腔种植修复术失败的主要原因是术后细菌在种植体表面黏附形成生物膜并导致周围炎症,主要致病菌为牙龈卟啉单胞菌(***,P.g),植入物相关感染严重影响手术效果及增加患者痛苦与费用,因此须赋予植体表面抗菌能力以降低感染发生率。微弧氧... 详细信息

口腔种植修复术失败的主要原因是术后细菌在种植体表面黏附形成生物膜并导致周围炎症,主要致病菌为牙龈卟啉单胞菌(***,P.g),植入物相关感染严重影响手术效果及增加患者痛苦与费用,因此须赋予植体表面抗菌能力以降低感染发生率。微弧氧化(Micro-arc oxidation,MAO)技术是通过高电压形成牢固结合且具备良好骨整合性能的氧化涂层,同时已有研究发现镁及其化合物(氧化镁)具有良好抗菌性和生物相容性。将MAO与电泳沉积(Electrophoretic deposition,EPD)技术结合,在多微孔的二氧化钛表面沉积纳米氧化镁(nano-MgO)涂层,并评价其体外抗菌性能及生物相容性。通过SEM、XRD、EDS观察样品表面形貌结构、测定元素组成。通过稀释涂板计数法、细菌活死染色及SEM观察评价nano-MgO涂层对P.g的体外抗菌性能。通过将人牙龈成纤维细胞(HGF)与nano-MgO涂层共培养后CCK-8法、细胞活死染色及骨架染色观察评价nano-MgO涂层体外生物相容性。研究结果发现,nano-MgO颗粒在二氧化钛多微孔表面均匀-团聚沉积且覆盖率随沉积时间增加。各组样品对P.g的体外抗菌性能在24 h为6%~54%,在72 h为39%~79%。显微观察(活死及SEM)样品表面活菌比例随沉积时间而减少。各组样品与HGF共培养1 d后细胞相对存活率为79%–67%,5 d后为93–85%。荧光显微观察发现MAO钛样品表面几乎无死细胞,其余4组表面死细胞比例随沉积时间增加,各组样品表面细胞形态完整且各组间无明显差异。MAO钛表面EPD nano-MgO涂层具备良好体外抗菌性能及生物相容性,研究成果可为降低口腔种植修复术的感染发生率、减少患者痛苦及手术费用提供一种新方法。

关键词：口腔种植体微弧氧化电泳沉积氧化镁抗菌

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Waring−Goldbach problem for one prime power and four prime cubes under Riemann Hypothesis

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Frontiers of Mathematics in China 2023年第2期18卷 139-146页

作者： Xiaoming PAN liqun hu Department of Mathematics Nanchang UniversityNanchang 330031China

Let k≥1 be an *** that RH *** this paper we prove that a suitable asymptotic formula for the average number of representations of integers n=p^(k)_(1)+p^(3)_(2)+p^(3)_(3)+p^(3)_(4)+p^(3)_(5),where p_(1),p_(2),p_(3),p... 详细信息

关键词： Hardy−Littlewood method Waring−Goldbach problem Riemann Hypothesis short intervals

基于第四代评价理论的高职理论课程教学评价探析

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科教导刊 2024年第4期 25-27页

作者：胡立群唐克静周文瑞湖北工业职业技术学院湖北十堰442000

当前,高职理论课程的学习评价形式主要以期末考试为主,这种终结性评价方式无法全面地反映学生的学习效果。文章首先对第四代评价理论进行概述,分析传统评价方法存在的问题,提出在理论课程评价中引入第四代评价理论的必要性,探讨在高职... 详细信息

当前,高职理论课程的学习评价形式主要以期末考试为主,这种终结性评价方式无法全面地反映学生的学习效果。文章首先对第四代评价理论进行概述,分析传统评价方法存在的问题,提出在理论课程评价中引入第四代评价理论的必要性,探讨在高职理论课程中从识别评价中的利益相关者、引导各利益相关者进行评价建构、运用解释学辩证性方法论并达成共识、搭建沟通平台以解决评价争议等方面进行有效课堂教学评价,对增强课堂教学监控、促进教学质量持续改进和提升人才培养质量具有积极意义。

关键词：第四代评价高职院校理论课程学习评价

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Parametric resonance of axially functionally graded pipes conveying pulsating fluid

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Applied Mathematics and Mechanics(English Edition) 2024年第2期45卷 239-260页

作者： Jie JING Xiaoye MAO hu DING liqun CHEN Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai Frontier Science Center of MechanoinformaticsShanghai Institute of Applied Mathematics and MechanicsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200444China Shanghai Institute of Aircraft Mechanics and Control Shanghai 200092China

Based on the generalized Hamilton's principle,the nonlinear governing equation of an axially functionally graded(AFG)pipe is *** non-trivial equilibrium configuration is superposed by the modal functions of a simply supported *** the direct multi-scale method,the response and stability boundary to the pulsating fluid velocity are solved analytically and verified by the differential quadrature element method(DQEM).The influence of Young's modulus gradient on the parametric resonance is investigated in the subcritical and supercritical *** general,the pipe in the supercritical region is more sensitive to the pulsating *** nonlinearity changes from hard to soft,and the non-trivial equilibrium configuration introduces more frequency components to the ***,the increasing Young's modulus gradient improves the critical pulsating flow velocity of the parametric resonance,and further enhances the stability of the *** addition,when the temperature increases along the axial direction,reducing the gradient parameter can enhance the response *** work further complements the theoretical analysis of pipes conveying pulsating fluid.

关键词： pipe conveying fluid axially functionally graded supercritical resonance multi-scale method parametric resonance

An improved interval model updating method via adaptive Kriging models

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Applied Mathematics and Mechanics(English Edition) 2024年第3期45卷 497-514页

作者： Sha WEI Yifeng CHEN hu DING liqun CHEN Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai Frontier Science Center of MechanoinformaticsShanghai Institute of Applied Mathematics and MechanicsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200072China Shanghai Institute of Aircraft Mechanics and Control Shanghai 200092China

Interval model updating(IMU)methods have been widely used in uncertain model updating due to their low requirements for sample ***,the surrogate model in IMU methods mostly adopts the one-time construction *** makes the accuracy of the surrogate model highly dependent on the experience of users and affects the accuracy of IMU ***,an improved IMU method via the adaptive Kriging models is *** method transforms the objective function of the IMU problem into two deterministic global optimization problems about the upper bound and the interval diameter through universal grey *** optimization problems are addressed through the adaptive Kriging models and the particle swarm optimization(PSO)method to quantify the uncertain parameters,and the IMU is *** the construction of these adaptive Kriging models,the sample space is gridded according to sensitivity *** sampling is then performed in key subspaces based on the maximum mean square error(MMSE)*** interval division coefficient and random sampling coefficient are adaptively adjusted without human interference until the model meets accuracy *** effectiveness of the proposed method is demonstrated by a numerical example of a three-degree-of-freedom mass-spring system and an experimental example of a butted cylindrical *** results show that the updated results of the interval model are in good agreement with the experimental results.

关键词： interval model updating(IMU) non-probabilistic uncertainty adaptive Kriging model surrogate model grey number

A viscoelastic metamaterial beam for integrated vibration isolation and energy harvesting

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Applied Mathematics and Mechanics(English Edition) 2024年第7期45卷 1243-1260页

作者： Long ZHAO Zeqi LU hu DING liqun CHEN Shanghai Institute of Applied Mathematics and Mechanics Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai Frontier Science Center of MechanoinformaticsSchool of Mechanics and Engineering Science Shanghai University School of Microelectronics Shanghai University

Locally resonant metamaterials have low-frequency band gaps and the capability of converging vibratory energy in the band gaps at resonant cells. It has been demonstrated by several researchers that the dissipatioin of vibratory energy within the band gap can be improved by using viscoelastic materials. This paper designs an integrated viscoelastic metamaterial for energy harvesting and vibration isolation. The viscoelastic metamaterial is achieved by a viscoelastic beam periodically arrayed with spatial ball-pendulum nonlinear energy harvesters. The nonlinear resonator with an energy harvesting function is achieved by placing a free-rolling magnetic ball in a spherical cavity with an additional induction coil. The dynamic equations of viscoelastic metamaterials under transverse excitation are established, and the energy harvesting and vibration isolation characteristics within the dispersion relation of viscoelastic metamaterials are analyzed. The results show that the vibrations of the main body of the viscoelastic metamaterial beam are significantly suppressed in the frequency range of the local resonance band gap. At the same time, the elastic waves are limited in the nonlinear resonator with an energy harvesting function, which improves the energy output. Finally, an experimental platform of viscoelastic metamaterial vibration is established for validation purposes.

关键词： viscoelastic metamaterial nonlinear vibration vibration isolation energy harvesting O326 70J35

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料仓落料过程中不同粒径颗粒的混合均匀性

中国粉体技术 2024年第1期30卷 79-89页

作者：褚嘉玮胡力群韩振强邵威长安大学公路学院特殊地区公路工程教育部重点实验室陕西西安710064

【目的】研究厂拌法施工过程中料仓落料环节对粒料混合均匀性产生的影响。【方法】采用离散单元法和多因素Box-Behnken响应面模型,探讨在落料过程中粒料的混合均匀性;设计网格均匀性指数(grid uniformity index,σ_(g))、竖向离析指数(v... 详细信息

【目的】研究厂拌法施工过程中料仓落料环节对粒料混合均匀性产生的影响。【方法】采用离散单元法和多因素Box-Behnken响应面模型,探讨在落料过程中粒料的混合均匀性;设计网格均匀性指数(grid uniformity index,σ_(g))、竖向离析指数(vertical segregation index,S_(v))、中心区域比例差值(center percentage difference,P_(c))指标,用于评价竖向、水平和网格划分粒料均匀性;研究贮料仓卸料漏斗的倾角、漏斗开口大小、颗粒间滚动摩擦系数对落料过程中粒料均匀性的影响。【结果】在颗粒间滚动摩擦系数为0.07时,选择倾角为55°、漏斗出口边长为400 mm的贮料仓漏斗,可以获得较为均匀的粒料分布。【结论】使用S_(v)、P_(c)和σ_(g)指标可以有效地评估落料过程中粒料的分布情况;漏斗倾角、漏斗开口大小、颗粒间滚动摩擦系数对粒料均匀性具有显著影响。

关键词：料仓道路材料均匀性离散元

Dynamics and vibration reduction performance of asymmetric tristable nonlinear energy sink

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Applied Mathematics and Mechanics(English Edition) 2024年第3期45卷 389-406页

作者： Hongyan CHEN Youcheng ZENG hu DING Siukai LAI liqun CHEN School of Mechanical Engineering University of Science and Technology BeijingBeijing 100083China Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai Frontier Science Center of MechanoinformaticsShanghai Institute of Applied Mathematics and MechanicsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200444China Department of Civil and Environmental Engineering The Hong Kong Polytechnic UniversityKowloonHong KongChina

With its complex nonlinear dynamic behavior,the tristable system has shown excellent performance in areas such as energy harvesting and vibration suppression,and has attracted a lot of *** this paper,an asymmetric tristable design is proposed to improve the vibration suppression efficiency of nonlinear energy sinks(NESs)for the first *** proposed asymmetric tristable NES(ATNES)is composed of a pair of oblique springs and a vertical ***,the three stable states,symmetric and asymmetric,can be achieved by the adjustment of the distance and stiffness asymmetry of the oblique *** governing equations of a linear oscillator(LO)coupled with the ATNES are *** approximate analytical solution to the coupled system is obtained by the harmonic balance method(HBM)and verified *** vibration suppression efficiency of three types of ATNES is *** results show that the asymmetric design can improve the efficiency of vibration reduction through comparing the chaotic motion of the NES oscillator between asymmetric steady *** addition,compared with the symmetrical tristable NES(TNES),the ATNES can effectively control smaller structural *** other words,the ATNES can effectively solve the threshold problem of TNES failure to weak ***,this paper reveals the vibration reduction mechanism of the ATNES,and provides a pathway to expand the effective excitation amplitude range of the NES.

关键词： asymmetric nonlinear energy sink(NES) tristable vibration control po-tential barrier