Self-Healable Triboelectric Nanogenerators: Marriage between Self-Healing Polymer Chemistry and Triboelectric Devices

Based on the triboelectrification and electrostatic induction coupling, triboelectric nanogenerators (TENGs) can convert mechanical energy into electrical energy, showing a promising potential in the fields of micro/nano energy and self-powered sensors applications. However, the devices are prone to malfunction due to fatigue and damage, limiting their development and applications. In this review, according to the working modes and operational malfunctions as well as the possible solutions, it is proposed that a robust TENG device can be constructed from three perspectives: self-healing friction layers, self-healing electrodes, and self-healing whole devices. Based on the structure, suitable environment, and self-healing materials, the design ideas and fabrication approaches of self-healing TENGs in recent years are summarized in detail. Finally, the development of self-healing TENGs in energy harvesting and self-powered sensors is outlined. It is the wish to provide insights and guidance for the application design of self-healing TENGs in the future.     

选择性激光熔化技术制备的Cu-10Sn合金的载流摩擦学性能

为提高Cu-10Sn合金接触线的力学及载流摩擦学性能,利用选择性激光熔化（SLM）技术制备Cu-10Sn合金,分析Cu-10Sn合金的组织结构及硬度等,研究不同载荷和电流对Cu-10Sn合金的载流摩擦学行为的影响;利用扫描电子显微镜对摩擦表面进行微观分析,揭示其磨损机制。试验结果表明：与载荷为10 N时相比,30 N时摩擦副的平均摩擦因数增大,接触电阻和电弧能量降低,磨损加剧;Cu-10Sn合金与GCr15球对摩,合金表面被氧化,铜元素被转移并粘附于对摩球上形成黏着磨损;与纯机械摩擦行为相比,载流条件下Cu-10Sn合金表面磨痕加深,黏着物、氧化物的数量明显增加,摩擦因数和磨损体积发生显著变化;小载荷小电流下磨痕表面出现电弧烧蚀现象;而电流为10 A时,磨损表面形成的氧化膜的润滑作用,减缓了材料的磨损。在无电流条件下磨损机制主要为疲劳磨损和黏着磨损;而在载流条件下,电化学氧化和黏着磨损显著增强。研究结论为SLM技术制备的铜锡合金应用于接触线等电传导接触材料提供参考。     

现场安装膜式水冷壁焊接质量的控制

随着我国经济建设的发展,对能源消耗,环保质量的要求越来越严格,在大、中型锅炉的设计、选型时,普遍选用膜式壁的型式应用于工业、电力和城市集中供热工程.其优点是安装周期较短,采用轻型材料筑炉,热能利用率高,检修容易等.但膜式壁的现场组焊难度很大,是我公司所面临的一次新的挑战.     

厦门太古飞机库檩条在风吸力作用下稳定承载力的试验研究

本文介绍了Z型檩条在模拟风吸力作用下稳定承载力分析的蒙皮支撑足尺模型试验研究,采用三种规范公式计算了其承载力,并与试验结果进行了比较,指出门式钢架规程、冷弯薄壁型钢规范及澳大利亚规范安全度均较高,博思格来实公司的镀锌钢檩条设计手册表值离试验值较接近,可靠度符合规范要求,具有良好的经济效益。在试验分析的基础上,指出撑杆与檩条的连接对于檩条承载力的发挥作用显著,对实际工程的设计施工提出了建议。     

Enzyme‐Catalyzed Formation of Supramolecular Hydrogels as Promising Vaccine Adjuvants

Promising vaccine adjuvants of self‐assembling peptide hydrogels for protein ovalbumin (OVA) are introduced in this study. The hydrogels are formed by the enzyme of phosphatase, and the vaccine adjuvant potency of both l ‐ and d ‐peptide hydrogels is evaluated. The results indicate that, compared with the clinically used alum adjuvant, both l ‐ and d ‐peptide hydrogels can increase the IgG production of OVA for about 1.3 and 3.8 times, respectively. Both gels can enhance antigen uptake and induce dendritic cell maturation, and promote and prolong accumulation of antigen in lymph node, as well as evoke germinal center formation. However, the d ‐peptide hydrogel with OVA exhibits a slightly more efficient accumulation of OVA in the lymph nodes and seems preventing tumor growth more significantly than its l ‐counterpart. With the good biocompatibility and degradability of peptide hydrogels, the hydrogels described in this study have big potential for the production of protein vaccines for immunotherapy against different diseases.     

厚壁压力容器声发射源定位精度分析

刘富君等人在论文“厚壁压力容器声发射技术声源定位误差分析”中,用实验与理论相结合的方式对厚壁压力容器定位误差进行了分析,作出了误差轨迹线。文章是在此基础上对该问题作了进一步的探讨,通过等价无穷小及忽略无穷小量等数学技巧,认为误差点近似位于同一直线上,与刘富君等人的实验数据相符,并得出了该直线的解析表达式,最后根据此直线方程提出了通过实际误差点反向移动特定距离来大幅缩小厚壁带来的误差,从而大大提高定位精度。     

深化投资体制改革 促进水东电站建设

在深化投资体制改革中，水东水电站建设采取了４家合资的办电方式，实行了项目法人责任制。项目法人抓总体规划、抓资金到位及管理、抓施工组织、抓质量监理、抓电站经营，并通过引入市场竞争机制，有效地控制工程造价。由于建设各方的共同努力，水东电站建设取得了可喜的成绩。     

Focused high frequency needle transducer for ultrasonic imaging and trapping

A miniature focused needle transducer (<1?mm) was fabricated using the press-focusing technique. The measured pulse-echo waveform showed the transducer had center frequency of 57.5 MHz with 54% bandwidth and 14?dB insertion loss. To evaluate the performance of this type of transducer, invitro ultrasonic biomicroscopy imaging on the rabbit eye was obtained. Moreover, a single beam acoustic trapping experiment was performed using this transducer. Trapping of targeted particle size smaller than the ultrasonic wavelength was observed. Potential applications of these devices include minimally invasive measurements of retinal blood flow and single beam acoustic trapping of microparticles.     

CO_2/CH_4分离膜技术在沼气提纯中的应用研究进展

生物天然气(BNG)是近年来新兴的一种可再生清洁能源.制备生物天然气的核心是去除沼气中的二氧化碳.CO2/CH4分离膜技术被认为是未来沼气提纯领域最有潜力的一项技术.本文对CO2/CH4分离膜技术在沼气提纯中的应用研究和发展现状进行综述,包括CO2/CH4分离膜材料的最新发展;膜法沼气提纯工艺过程的设计;欧美膜法沼气提纯工业化装置的近况等;最后对膜法沼气提纯技术的主要困难及未来发展方向进行分析与讨论.     

Backscattering measurement from a single microdroplet

Backscattering measurements for acoustically trapped lipid droplets were undertaken by employing a P[VDF-TrFE] broadband transducer of f-number = 1, with a bandwidth of 112%. The wide bandwidth allowed the transmission of the 45 MHz trapping signal and the 15 MHz sensing signal using the same transducer. Tone bursts at 45 MHz were first transmitted by the transducer to hold a single droplet at the focus (or the center of the trap) and separate it from its neighboring droplets by translating the transducer perpendicularly to the beam axis. Subsequently, 15 MHz probing pulses were sent to the trapped droplet and the backscattered RF echo signal received by the same transducer. The measured beam width at 15 MHz was measured to be 120 μ m. The integrated backscatter (IB) coefficient of an individual droplet was determined within the 6-dB bandwidth of the transmit pulse by normalizing the power spectrum of the RF signal to the reference spectrum obtained from a flat reflector. The mean IB coefficient for droplets with a 64 μ m average diameter (denoted as cluster A) was -107 dB, whereas it was -93 dB for 90-μm droplets (cluster B). The standard deviation was 0.9 dB for each cluster. The experimental values were then compared with those computed with the T-matrix method and a good agreement was found: the difference was as small as 1 dB for both clusters. These results suggest that this approach might be useful as a means for measuring ultrasonic backscattering from a single microparticle, and illustrate the potential of acoustic sensing for cell sorting.