实验设备运行状况监测系统的设计与实现

针对高校设备利用率低的现象,提出了一种基于电流监测的实验设备运行状况监测系统实现方法。系统以STC12C5A60S2为电流监测模块控制器。结合Zigbee和485总线通信方式,将实验设备运行状况的信息进行集中管理,以较小的代价,大大简化了监督实验设备使用情况的工作流程,给管理人员提供了极大的便利。经过测试表明,该系统可以运行正常、稳定,可以适应断电等情况,完全满足设计需求,具有较高的推广应用价值。     

MEMIS: A Mobile-Supported English-Medium Instruction System

Education is one of the most important elements in our lives, as it provides a direct gain in knowledge. Thus, in order to provide better academic achievement, more and more instructors are adapting collaborative learning to their classes. However, two major problems lurk behind collaborative learning. First, it is difficult to apply collaborative learning because students tend to engage passively with traditional lectures. As a result, interactive technologies such as clickers have been applied to increase interactive learning and raise the rate of interaction. Nevertheless, these interactive technologies still have some limitations, such as limited mobility, high costs, setup issues, technical difficulties, and little support of higher-order thinking skills. Second, recently there has been an increasing number of EMI (English as Medium of Instruction) courses added to university course offerings in countries where English is not the first language. The goal of these courses is to support university internationalization and address the global status of English. However, it is even harder to achieve in-class interaction in large EMI lecture courses. In addition, some studies argue that EMI courses might affect the overall learning of course content because of students’ poor lecture comprehension and passive engagement in class.In order to address the limitations of interactive technologies, encourage more collaborative learning, facilitate greater in-class interaction in large lecture courses, and resolve students’ poor lecture comprehension in EMI courses, the author introduces MEMIS (Mobile-Supported English-Medium Instruction System), which includes both a T&S (Teachers & Students) mobile app and an EMI pedagogical method. The author first provides detailed implementation and all the features of the T&S mobile app, which improves students’ perceptions of classroom participation and in-class interaction. Then the author explains how she develops her EMI pedagogy such that it utilizes the features of the T&S mobile app to: 1) increase students’ overall learning in her EMI course, 2) develop students’ construction of knowledge and higher-order thinking, and 3) achieve all six cognitive processes from Bloom’s revised taxonomy. The author adapts a quasi-experimental design, statistically analyzes the effectiveness of both exam scores and final grades between a control group and an experimental group, and then asks students to evaluate their experiences and provide feedback about MEMIS. Based on both statistical results and students’ overall feedback, the author confirms that MEMIS is an effective approach that improves lecture comprehension, encourages more class engagement, promotes collaborative learning, and achieves better learning outcomes.     

脉冲红外激光助视夜视技术研究

在分析微光夜视系统视距理论的基础上．论证了用脉冲红外激光阵列助视提高微光夜视系统视距的可行性。针对激光助视易于暴露的缺陷,提出了微光夜视伪随机瞬态激光增强技术。系统研究了伪随机编码理论,并硬件实现了瞬态激光伪随机编码调制及同步图像捕捉控制电路。建立了脉冲红外激光助视微光夜视系统,进行了多次室内、野外试验及试验结果观测评估,取得了较好效果。     

矩量法分析埋地三维目标的近场电磁散射

采用混合位积分方程（MPIE）和基于RWG基函数的矩量法分析计算了埋地三维目标的近场电磁散射问题,利用二级离散复镜像（DCIM）和广义函数束（GPOF）相结合的方法求解近场Sommerfeld积分,很好地解决了多层媒质中电磁散射计算中的棘手问题,其方法简练、精确、高效,数值分析结果与有关文献吻合很好,证实了该方法的正确性和通用性。此外,该文还通过计算比较了不同观察点、不同目标埋地深度及不同地层媒质参数的电磁散射特性。     

Sol Electrolyte: Pathway to Long-Term Stable Lithium Metal Anode

Lithium (Li) metal batteries are the subject of intense study due to their high energy densities. However, uncontrolled dendrite growth and the resulting pulverization of Li foil during the repeated plating/stripping process seriously diminish their cycling life. Herein, a facile approach using octaphenyl polyoxyethylene (OP-10)-based sol electrolyte is proposed to alleviate Li anode pulverization. This sol electrolyte possesses better ionic conductivity compared to gel and solid-state electrolytes and also homogenizes Li ion diffusion throughout the entire electrolyte efficiently. As a result, Li/Li symmetric cells using this sol electrolyte demonstrate long-term cycling stability for up to 1800 h, with a plating capacity of 3.0 mAh cm⁻² without deteriorating the integrity of the thin Li foil. Using a conventional liquid electrolyte, electrode pulverization and battery failure can be observed after just three cycles. More importantly, a parameter of “throwing power” is introduced in a metal Li battery system to characterize the homogenizing ability of Li deposition in different electrolyte systems, which can serve as a guide to the efficient selection of electrolytes for Li metal batteries.     

基于双路径递归网络与Conv-TasNet的多头注意力机制视听语音分离

目前的视听语音分离模型基本是将视频特征和音频特征进行简单拼接,没有充分考虑各个模态的相互关系,导致视觉信息未被充分利用,分离效果不理想。该文充分考虑视觉特征、音频特征之间的相互联系,采用多头注意力机制,结合卷积时域分离模型(Conv-TasNet)和双路径递归神经网络(DPRNN),提出多头注意力机制时域视听语音分离(MHATD-AVSS)模型。通过音频编码器与视觉编码器获得音频特征与视频的唇部特征,并采用多头注意力机制将音频特征与视觉特征进行跨模态融合,得到融合视听特征,将其经DPRNN分离网络,获得不同说话者的分离语音。利用客观语音质量评估(PESQ)、短时客观可懂度(STOI)及信噪比(SNR)评价指标,在VoxCeleb2数据集进行实验测试。研究表明,当分离两位、3位或4位说话者的混合语音时,该文方法与传统分离网络相比,SDR提高量均在1.87 dB以上,最高可达2.29 dB。由此可见,该文方法能考虑音频信号的相位信息,更好地利用视觉信息与音频信息的相关性,提取更为准确的音视频特性,获得更好的分离效果。     

Scalable Construction of Multifunctional Protection Layer with Low-Cost Water Glass for Robust and High-Performance Zinc Anode

Zinc ion batteries (ZIBs) have recently attracted tremendous interest for being low-cost, environmentally benign, and high energy density. However, the large-scale practical application of ZIBs is hampered by well-known undesirable dendrite growth and serious side reactions of the Zn anode during the long-term cycling process. Herein, a multifunctional water-glass artificial protection layer with enormous Si─O functional groups is constructed on Zn anode through a simple spin-coating method. The theoretical and experimental investigation suggests that the as-constructed interface with rich Si─O hydrophilic functional groups on Zn anode could facilitate the even distribution of electric field distribution and homogeneous wettability, navigate uniform zinc deposition/stripping along the (002) plane, and subsequently lead to well-suppressed dendrite growth and effective prohibition of oxygen-involved corrosion. Consequently, the water glass-modified anode achieves highly reversible Zn plating/stripping over 1500 h at a high current density of 10 mA cm⁻² in symmetrical cells, and a high capacity retention ratio of 79.4% at the current density of 5 A g⁻¹ in full cells paired with V₂O₅ cathode. This proposed water glass coating layer design is cheap, up-scalable, and facile, which could substantially accelerate the rapid commercialization of zinc anodes and unleash the full potential of renewable ZIBs for next-generation large-scale energy storage.     

可信网络的发展及其面对的技术挑战

随着信息网络的基础性、全局性作用日益增强,传统的网络理论与技术,尤其是网络安全,已经不能满足网络发展的需要,提供系统的安全可信的服务已经成为网络研究的新趋势。本文认为可信网络应该是网络和用户的行为及其结果总是可预期与可管理的。网络可信主要包括服务提供者的可信、网络信息传输的可信性和终端用户的可信等3个方面的内容。从网络与用户行为的可信模型、可信网络的体系结构、服务的可生存性、网络的可管理性4个方面进行研究,以便为解决可信网络面临的科学问题提供思路。     

Controlled Synthesis of Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>/Ag Core–Shell Composite Nanoparticles with High Electrical Conductivity

The presented method provides an easy processing route to synthesize Fe₃O₄/Ag core–shell composite nanoparticles. Their structures were characterized by x-ray diffraction and transmission electron microscopy. The average size of the Fe₃O₄ core and Ag shell was about 32.0 nm and 5.0 nm (or 28.0 nm), respectively. Furthermore, magnetic measurements showed that the composite nanoparticles exhibited typical superparamagnetic behavior, specific saturation magnetization of ca. 24.0 emu/g, and intrinsic coercivity of 106.0 Oe. At the same time, high conductivity (64.7 S/cm) of the composite nanoparticles was also observed. This method provides an opportunity to synthesize other core–shell (Fe₃O₄) nanoparticles in a single step.     

Inhibition of Whisker Growth on the Surface of Sn-3Ag-0.5Cu-0.5Ce Solder Alloyed with Zn

Solder alloys doped with rare-earth elements have been reported to show many beneficial effects. However, tin whiskers have been observed to appear on the surface of Sn-3Ag-0.5Cu-0.5Ce solder joints after air exposure for short periods. Such a phenomenon of abnormal whisker growth may significantly degrade the reliability of electronic packaging. The present study shows that the tin whiskers can be prevented by the addition of 0.5 wt.% Zn into a Sn-3Ag-0.5Cu-0.5Ce solder. The inhibition effect on the whisker growth is correlated to the refining of (Ce_0.9Zn_0.1)Sn₃ intermetallics in this Sn-3Ag-0.5Cu-0.5Ce-0.5Zn alloy.