摘要：Wet-resistant flexible electronics have acquired increasing attention on applications in wet environments,such as sweaty skin, rainy weather, biological fluids, and underwater. However, it remains challenging to achieve nonswelling and underwater self-healing hydrogel sensors for the mechanical perception in aqueous solutions. Herein, a selfhealing and non-swellable hydrogel is successfully fabricated,which presents an automatically healing behavior in various aquatic environments, including deionized water, seawater,sweat, alkali and acidic aqueous solutions. Moreover, the hydrogel demonstrates high stretchability and stable electromechanical sensing properties in water. Furthermore, an electronic skin is designed with the features of fast responsiveness, reliability, and high sensitivity for detecting breathing, speaking, coughing, and diverse body movements. The self-healing hydrogel sensors enable a brilliant mechanical sensibility for detecting a series of dynamic stimuli in air and underwater, even after the healing of fracture interface in water. The underwater self-healing and anti-swelling hydrogel would provide enticing potential on various stable electronic devices for aquatic environments, such as implantable electrodes, triboelectric nanogenerators, and underwater soft robotics.

摘要：Ionic hydrogel-based sensors have shined a spotlight on wearable ***,the sensitivity and reliability of hydrogel devices are significantly hampered by the weak adhesion of skin-sensor interface as well as inferior temperature ***,inspired by the structure and composition of dermis,a novel skin-attachable and environment-stable hydrogel was designed by integrating collagen into the LiCl-containing chemically cross-linked polyacrylamide *** hydrogel exhibited skin-like mechanical properties of low modulus,superior stretchability as well as excellent ***,the introduction of collagen endowed the hydrogel with robust and seamless interfaces with diverse materials,including the curved *** a result,the hydrogel is capable of serving as a human-machine interface for collecting reliable electrocardiography(ECG)signals and discerning various human motions,with high sensitivity(gauge factor=10.7),fast response,negligible hysteresis as well as extensive monitoring ***,the hydrogel that can mimick the temperature-tolerant mechanism of most organisms possesses persistent stabilization of adhesive,conductive,sensory and mechanical performances at subzero or ambient *** skin-inspired strategy paves an effective way for the design of multifunctional materials with potential applications in next-generation electronics.

摘要：离子导电水凝胶由于其在生物相容性、导电性和灵活性方面的独特优势,已成为可穿戴式人体运动检测传感器的最有希望的替代品之一.然而,目前的水凝胶电子器件仍然面临着不可重复使用性和单一信号检测功能的限制.在此,我们通过模拟生物体的网络结构和离子传导机制,制备了基于聚乙烯醇、海藻酸纤维和胶原蛋白的离子导电水凝胶,用于人体运动和电生理信号的双模式信号采集.通过海藻酸纤维和胶原蛋白的协同调节,水凝胶表现出类似皮肤的机械性能,具有低模量、高韧性和抗疲劳性,从而可以最大限度地提高水凝胶可穿戴传感器的穿着舒适度和运动检测能力.此外,具有与生物体相似离子传输行为的水凝胶导体可以用作表皮电极,收集包含重要人体生理信息的表皮电位.通过对可穿戴设备的合理设计和组装,水凝胶不仅可以连续、准确地识别全身运动信号,还可以采集肌电图、心电图等不同电生理信号.值得注意的是,这种基于非共价交联结构的水凝胶是完全可回收的,可以任意重组为新的电子器件,同时保持原有功能,提高水凝胶的可重复使用性,减少电子浪费.

摘要：建立了电液集成式液压提升机电液速度伺服控制系统的数学模型,在系统参数对比分析的基础上,对原数学模型进行了简化。利用动态仿真软件Simulink建立了数学模型简化前后的仿真模型。利用MATLAB仿真程序研究了系统的动态特性,并据此进行了滞后校正,以满足系统设计要求。

摘要：人工智能时代,通过课堂教学提升学生高阶思维愈加重要。本文阐释了地理高阶思维的内涵与研究现状,发现当前地理高阶思维相关研究忽视了知识层面。据此,本文引入“强有力知识”理论,结合知识分类与同课异构教学设计分析“强有力知识”取向下的地理高阶思维培养策略。

摘要：关于体内静脉循环的纳米级核磁成像分子探针的设计,本研究利用热降解方法制备单一分散的四氧化三铁纳米粒子,利用溶剂增发的方法将四氧化三铁纳米包覆在嵌段式聚醚Pluronic F127聚合物胶束内。由于分子间疏水作用,四氧化三铁纳米粒子与胶束的疏水嵌段紧密结合,被包覆在胶束的核内部。对此成像剂的基本性质的测定,结果显示,胶束粒子的粒径为75 nm～80 nm,在弱酸弱碱性水相条件下仍然保持稳定状态,有利于长期的稳定的体内静脉循环。此外,通过对粒子的弛豫度的测定和计算,得出T2=144.5 mM-1s-1,说明了这种聚合物基粒子可以做为T2加权的核磁成像剂。

摘要：本文以杭州玉皇山地质考察为例,聚焦地理户外考察的设计,包括选址策略、学情分析、教学目标,梳理了地理户外考察的实施过程。结合对地理户外考察实施过程中问题的反思,提出教师地理实践指导素养亟待加强;学生学习方式转向实践;教学评价注重多元化过程性等建议。

摘要：基本公共服务均等化的价值定位事关其目标设计和路径选择,对实际推行过程中的具体部署和可能走向具有重要影响。只有明确基本公共服务均等化的价值定位,才能调和理念、凝聚共识,为与此相关的顶层设计提供相应的理论支持。对于基本公共服务均等化的价值定位,可以从三个方面加以把握:其一,社会公正是引领基本公共服务均等化的根本导向;其二,成果共享是实现基本公共服务均等化的核心理念;其三,人的尊严是推行基本公共服务均等化的最终归宿。

摘要：项目化学习是一种新的教学理念和方式,代表了当下学习方式变革的实践。本文以“区域及其类型”为例,基于逆向设计思维,融入图寻游戏,建构了地理项目化学习的实施路径:提取核心概念,确定项目主题;立足真实情境,设计驱动问题;组织实践活动,助力高阶认知;制作项目成果,推动反思复盘;全程多元评价,实施逆向设计。本文为提升学生区域认知素养、激发学科兴趣提供了新的教学启示。

摘要：根据无纬带绑扎机带式制动器的摩擦力学与热力学模型,进行了制动器稳态与瞬态热效应分析,确定了摩擦热与摩擦功率之间的关系。探讨了摩擦热量在摩擦副材料中的分配状况,研究并得到了摩擦副平衡温度和摩擦副可长期连续工作的条件。建立了基于ANSYS的制动器热效应分析模型,得到不同时间摩擦副温度场分布状况和温度随时间变化的状况。