溢流堰表孔弧形闸门开启过程水力特性3维数值模拟

基于动网格技术和VOF方法对某工程宽尾墩泄洪表孔弧形闸门开启过程进行了3维数值模拟研究。为获得详细的水力特性,采用3种不同的开启速度。获得了闸门区、宽尾墩及消力池的压力、速度等水力参数的时空变化规律和易发生空化空蚀的时刻与区域,指出闸门开启过快时的不利因素,并将部分结果与试验进行对比,吻合良好,验证了数值方法是可靠的,可为确定闸门的合理运行方式及工程体型优化提供重要的参考依据。     

超声波无线能量传输技术应用与研究进展

无线能量传输技术是目前研究的热点,该技术可以为无线设备的供电提供一种解决方案,同时可有效提高设备供电的可靠性、便捷性和安全性.超声波无线能量传输技术作为其中的一种新兴技术,受到了越来越多的关注.阐述了超声波无线能量传输技术的基础,对几种不同介质中的超声波无线能量传输技术研究现状进行分析,最后针对超声波无线电能传输技术的不足及发展前景进行了探讨与展望.     

延安时期红色美术创作的革命艺术诠释

通过分析延安时期红色美术作品独有的艺术构建,思考当前新时代社会下,红色美术作品所具备的历史价值与影响,以此来引导传播红色美术在特殊时期独特的艺术性价值其实,为发展传承革命传统而创作的艺术方向发展.     

Bio‐Orthogonal T Cell Targeting Strategy for Robustly Enhancing Cytotoxicity against Tumor Cells

T cells can kill tumor cells by cell surface immunological recognition, but low affinity for tumor‐associated antigens could lead to T cell off‐target effects. Herein, a universal T cell targeting strategy based on bio‐orthogonal chemistry and glycol‐metabolic engineering is introduced to enhance recognition and cytotoxicity of T cells in tumor immunotherapy. Three kinds of bicycle [6.1.0] nonyne (BCN)‐modified sugars are designed and synthesized, in which Ac₄ManN‐BCN shows efficient incorporation into wide tumor cells with a BCN motif on surface glycans. Meanwhile, activated T cells are treated with Ac₄GalNAz to introduce azide (N₃) on the cell surface, initiating specific tumor targeting through a bio‐orthogonal click reaction between N₃ and BCN. This artificial targeting strategy remarkably enhances recognition and migration of T cells to tumor cells, and increases the cytotoxicity 2 to 4 times for T cells against different kinds of tumor cells. Surprisingly, based on this strategy, the T cells even exhibit similar cytotoxicity with the chimeric antigen receptor T‐cell against Raji cells in vitro at the effector: target cell ratios (E:T) of 1:1. Such a universal bio‐orthogonal T cell‐targeting strategy might further broaden applications of T cell therapy against tumors and provide a new strategy for T cell modification.     

加载速率对单晶γ-TiAl裂纹扩展影响的分子动力学模拟

运用分子动力学方法研究微观尺度下单晶γ-TiAl裂纹的扩展过程,运用嵌入原子势进行模拟,得到裂纹扩展的轨迹图和能量演变图,比较分析不同加载速率对γ-TiAl能量和应力-应变关系的影响,进而揭示对裂纹扩展的影响。研究表明:随着加载速率的增大,体系的原子运动加剧,总能量上升到峰值的剧烈程度增加,试件断裂的时间缩短,所需的应变越小,而裂纹扩展的形态没有变化;总能量随时间的演化曲线只出现一个峰值。应力-应变曲线中只有弹性阶段,没有塑性阶段,加载速率对拉升过程的弹性变形机理没有影响。     

Event-triggered average dwell time control for switched uncertain linear systems with actuator saturation

This paper investigates an event-triggered average dwell time (ADT) control method for switched systems with dynamic uncertainty and actuator saturation. An event-trigger is employed and only few necessary data are authorised to be transmitted to the controller by the event-trigger when its threshold is violated. Since the time-intervals of system switching signal and data releasing time-intervals of the event-trigger share common time-sequence yet not inter-influenced, an ADT control law is proposed for guaranteeing system exponential stability; meanwhile, the actuator saturation limitation is also considered. More significantly, a minimal data releasing time-interval of the event-trigger is given and it has been proved that the event-trigger cannot be violated during that time-interval. Numerical example is provided to demonstrate the effectiveness of the proposed method.     

Research on the chaotic secure communication of the phase-space symmetric Lorenz oscillator group

To meet the demand of chaotic oscillators for large scale secure communications,the Lorenz oscillator was taken as an example,a phase-space symmetric chaotic oscillator group model was proposed and the synchronization problem was studied.According to the condition of synchronization,a communication model based on symmetric chaotic oscillator was constructed and verified by simulation.The symmetrical oscillator group can provide an infinite number of symmetric chaotic oscillators,which can satisfy the application in large-scale secure communication and maintain the excellent characteristics of the original chaotic oscillator,and has a good application prospect.     

形状可调的5次组合样条及其参数选择

目的 为了克服3次参数B样条在形状调整与局部性方面的不足,提出带参数的5次多项式组合样条。方法 首先构造一组带参数的5次多项式基函数;然后采用与3次B样条曲线相同的组合方式定义带参数的5次多项式组合样条曲线,并讨论基于能量优化法的5次组合样条曲线参数最佳取值问题;最后定义相应的组合样条曲面,并研究利用粒子群算法求解曲面的最佳参数取值。结果 5次组合样条不仅继承了3次B样条的诸多性质,而且还比3次B样条具有更强的局部性及形状可调性。由于5次组合样条仍为多项式模型,因此方程结构相对较为简单,符合实际工程的需要。利用能量优化法可获得光顺的5次组合样条曲线与曲面。结论 所提出5次多项式组合样条克服了3次参数B样条在形状调整与局部性方面的不足,是一种实用的自由曲线曲面造型方法。     

Influence of the ambient illuminance on the subjective brightness measurements

The subjective brightness is determined by not only the display screen luminance but also the light surrounding the display. A metric for space brightness named “Feu” is adopted to consider the effect of luminance distribution. The relation between the pupil diameter and the space brightness is applied to obtain the subjective brightness. The measured subjective brightness is obtained both for direct‐view display and augmented reality (AR) display. The results indicate that the measured subjective brightness is much closer to the perceived result. The subjective brightness increases along with the increase of the screen luminance under the same ambient illuminance. While under the same screen luminance, the subjective brightness decreases with the increase of the ambient illuminance in most cases.     

带局部形状参数的λ-B曲线设计

目的 目前有很多研究B样条曲线的含参数扩展,给出的曲线都具备B样条曲线的局部形状控制性以及独立于控制顶点的形状可调性,但有些文献给出的参数是全局的,导致曲线不具备局部形状调整性,有些文献给出的调配函数不具有全正性,导致曲线不具备变差缩减性、保凸性。本文的出发点是构造同时具备保凸性、局部形状调整性、局部形状控制性的曲线。方法 首先运用拟扩展函数空间的理论框架证明了已有的3次Bézier曲线的扩展基,简称λμ-Bernstein基,恰好为所在空间中的规范B基。然后运用λμ-Bernstein基的线性组合来构造3次均匀B样条曲线的扩展基,根据预设的曲线性质反推出扩展基的性质,进而求出线性组合的系数,得出扩展基的表达式。扩展基可以表示成λμ-Bernstein基与一个转换矩阵的乘积,证明了转换矩阵的全正性,由扩展基定义了一种结构与3次B样条曲线相同的含一个局部形状参数的分段曲线。结果 转换矩阵的全正性决定了扩展基的全正性,扩展基的全正性决定了扩展曲线的变差缩减性、保凸性,形状参数的局部性决定了曲线的局部形状调整性,曲线的分段结构决定了曲线的局部形状控制性。结论 本文给出的构造具有全正性的B样条扩展基的方法具有一般性,与现有众多扩展曲线相比,本文方法构造的曲线因为具有变差缩减性和保凸性,从而为保形设计提供了一种有效方法。