摘要：This paper is concerned with the problems of robust admissibility and static output feedback( SOF)stabilization for a class of discrete-time switched singular systems with norm-bounded parametric *** objective is to design a suitable robust SOF controller guaranteeing the regularity,causality and asymptotic stability of the resulting closed-loop system under arbitrary switching laws. Based on the basic matrix inequality sufficient condition for checking the admissibility of switched singular systems,together with some matrix inequality convexifying techniques,the SOF controller synthesis is developed for the underlying systems. It is shown that the controller gains can be obtained by solving a set of strict linear matrix inequalities( LMIs). A simulation example is given to show the effectiveness of the proposed method.

摘要：Drop-on-demand (DOD) bioprinting has been widely used in tissue engineering due to its highthroughput efficiency and cost effectiveness. However, this type of bioprinting involves challenges such as satellite generation, too-large droplet generation, and too-low droplet speed. These challenges reduce the stability and precision of DOD printing, disorder cell arrays, and hence generate further structural errors. In this paper, a multi-objective optimization (MOO) design method for DOD printing parameters through fully connected neural networks (FCNNs) is proposed in order to solve these challenges. The MOO problem comprises two objective functions: to develop the satellite formation model with FCNNs;and to decrease droplet diameter and increase droplet speed. A hybrid multi-subgradient descent bundle method with an adaptive learning rate algorithm (HMSGDBA), which combines the multisubgradient descent bundle (MSGDB) method with Adam algorithm, is introduced in order to search for the Pareto-optimal set for the MOO problem. The superiority of HMSGDBA is demonstrated through comparative studies with the MSGDB method. The experimental results show that a single droplet can be printed stably and the droplet speed can be increased from 0.88 to 2.08 m·s^-1 after optimization with the proposed method. The proposed method can improve both printing precision and stability, and is useful in realizing precise cell arrays and complex biological functions. Furthermore, it can be used to obtain guidelines for the setup of cell-printing experimental platforms.

摘要：传统刺绣技艺历史悠久,承载着深厚的文化底蕴,具有丰富的艺术表现力。随着时代的变迁,传统刺绣技艺的影响力也在不断提升。在现代社会,刺绣不仅是民族文化身份的重要象征,也是服装设计领域中重要的艺术元素。因此,有必要深入探讨传统刺绣技艺在现代服装中的应用与传承,分析所面临的挑战,从而为传统刺绣技艺的现代化发展提供新的视角,促进现代时尚产业的创新发展。

摘要：《义务教育科学课程标准(2022年版)》明确科学课程要在整体设计的基础上开展主题教研,创新教研方式和手段,提高针对性与实效性,为教师专业发展提供服务和引领。区域在调查分析教师对科学教育教学改革的专业需求的基础上,探究当前教研活动中存在的问题与矛盾,设计了基于“多层次支持系统”的主题教研组织框架,细化形成了工作坊、同伴辅导和导师指导等活动方式,在整体分层设计和互动、个性的推进中提升了科学教师对新课标的理解与认识,发展了素养导向下课堂教学实践的能力,为学生核心素养的发展奠定了坚实基础。

摘要：国内样品辐照资源有限,可供选择的反应堆数量少,反应堆开启频率低,缺乏对反应堆辐照样品参数的系统研究,在不同程度上制约了^(40)Ar/^(39)Ar定年科研进展,需要开拓新的辐照资源.首次研究西安脉冲堆(XAPR)用于^(40)Ar/^(39)Ar定年样品的辐照条件,通过黑云母标准物质ZBH-25确定中子通量的径向梯度和轴向梯度变化情况,并通过钾盐和钙盐获得反应堆的副反应校正因子.结果表明辐照孔道径向J值变化幅度较小,仅为0.49%,且包含中子通量的峰值,表明样品处于反应堆中心位置进行辐照.辐照孔道轴向中子通量梯度为0.54%/cm,XAPR辐照孔道内的校正因子(^(40)Ar/^(39)Ar)K=0.002 082 6、(^(39)Ar/^(37)Ar)Ca=0.000 776 92、(^(36)Ar/^(37)Ar)Ca=0.000 299 98.对标准物质ZBH-25黑云母进行年龄测定,证明此反应堆满足^(40)Ar/^(39)Ar定年样品的辐照条件,可以作为一个新的辐照源.

摘要：现行安全性评价规范缺乏针对四级、等外公路等低指标公路的线形设计安全性指导,为此提出了一种检验山区低指标复杂线形公路行驶安全性的方法:基于CarSIM/TruckSIM仿真软件平台搭建“人-车-路”系统仿真,选取代表性车型,以实车行驶数据为仿真参数设置依据,开展车辆虚拟行驶试验,利用速度、横向稳定性、驾驶操纵性、速度调控等四类指标,分析被检公路的公路几何设计符合性、速度协调性、驾驶操纵负荷、事故易发路段甄别、连续纵坡路段安全性。通过运行与实车试验相似的虚拟仿真行驶实验验证了“人-车-路”仿真方法的可行性,并且选取了1条四级公路、1条等外公路为实例,结果表明,该方法能有效检验出公路线形设计组合指标超低限的、不协调的线形单元,驾驶操纵负荷较大、均衡性较差的路段,危险路段及对应的车辆事故形态和临界安全速度,重型载重货车通过回头曲线越出行车道的位置及越出宽度;进而可以根据危险路段的行驶/事故状况提出靶向性的几何参数改善措施,增加车辆在山区低指标复杂线形公路行驶的通过性和稳定性,最终达到提高山区低指标公路的线形设计质量和行驶安全性的目的。

摘要：乡土建筑一直以来都是具有独特魅力和价值的建筑形态,而竹材作为一种天然生态材料,在乡土建筑中扮演着重要角色。本文旨在分析竹材在乡村建设中的价值挖掘及应用,并从物质、生态、建造及形态四个层面探索乡土性竹建筑设计,指出结合新型材料的乡土化、构建新型竹结构、节点连接方式的更新、三维形态的本体化设计、生态层面的可持续设计是建构乡土性竹建筑的关键策略。

摘要：This study presents the RF design of a linear accelerator(linac)operated in single-bunch *** accelerator is powered by a compressed RF pulse produced from a SLED-I type RF pulse *** compressed RF pulse has an unflattened shape with a gradient distribution which varies over the structure *** analytical study to optimize the accelerating structure together with the RF pulse compressor is *** optimization aims to maximize the efficiency by minimizing the required RF power from the generator for a given average accelerating *** study shows that,owing to the compressed RF pulse shape,the constant-impedance structure has a similar efficiency to the optimal structure using varying iris *** constant-impedance structure is easily fabricated and is favorable for the design of a linac with a pulse *** utilize these findings to optimize the RF design of a X-band linac using the constant-impedance accelerating structure for the Tsinghua Thomson X-ray source facility.

摘要：传统的考虑地震作用的边坡风险率分析普遍采用特定地震参数作为计算的前置条件,忽略了地震参数的不确定性。为此,提出了地震作用下的库岸边坡综合风险率等级评估方法,即首先采用极值Ⅱ型分布模型建立50年设计基准期内的地震峰值加速度(PGA)概率密度函数;然后采用基于有限元的改进一次二阶矩法计算库岸边坡的失效概率,在全概率理论框架下进行积分得到地震作用下的综合风险率;最后采用该方法对某库岸边坡进行风险率分析。结果表明,该库岸边坡在地震作用下的综合风险率为0.0994,对应5级风险概率,可见该方法能够充分考虑不同PGA的发生概率及滑动面内部材料参数的随机性,可对工程的风险率等级作出合理客观评价,且提高了评估的全面性。

摘要：传统的浪涌保护电路对元器件的功率等级要求较高,导致整个电路结构的性能降低,硬件成本提高.设计了一种低成本带吸收电容防浪涌的电路.通过理论分析、软件仿真以及实验测试证明了该电路结构采用更低功率等级的金属-氧化物半场效晶体管(metal-oxidesemiconductor field-effect transistor,MOSFET),能在降低浪涌保护电路成本的同时,提升浪涌电路电压等级以及电路的稳定性.