Highly Energy-Dissipative,Fast Self-Healing Binder for Stable Si Anode in Lithium-Ion Batteries

A double-wrapped binder has been rationally designed with high Young's modulus polyacrylic acid (PAA) inside and low Young's modulus bifunctional polyurethane (BFPU) outside to address the large inner stress of silicon anode with drastic volume changes during cycling. Harnessing the “hard to soft” gradient distribution strategy, the rigid PAA acts as a protective layer to dissipate the inner stress first during lithiation, while the elastic binder BFPU serves as a buffer layer to disperse residual stress, and thus avoids structural damage of rigid PAA. Moreover, the introduction of BFPU with fast self-healing ability can dynamically recover the microcracks arising from large stress, further ensuring the integrity of silicon anode. This multifunctional binder with smart design of double-wrapped structure provides enlightenment on enlarging the cycling life of high-energy-density lithium-ion batteries that suffer enormous volume change during the cycling process.     

Molybdenum Dioxide Nanoparticles Anchored on Nitrogen-Doped Carbon Nanotubes as Oxidative Desulfurization Catalysts: Role of Electron Transfer in Activity and Reusability

Electron transfer between metal-oxides and supports considerably affects the oxidative desulfurization (ODS) performance of catalysts, while this is far from being well understood. Herein, molybdenum dioxide with oxygen vacancies (V_O-MoO₂) catalysts derived from Mo-based metal-organic frameworks are anchored on electron-rich nitrogen-doped carbon nanotubes (NC) to obtain excellent ODS activity and reusability. Results show that either dibenzothiophene (DBT) or 4,6-dimethyldibenzothiophene (4,6-DMDBT) is removed 100% on the composite catalyst (V_O-MoO₂@NC) within 40 min of reaction when cumene hydroperoxide is chosen as an oxidant. After five cycles of reaction, DBT and 4,6-DMDBT removal still exceeded 99.5 and 95.0%, respectively. Results from density functional theory calculations and characterizations confirm that the strong electron-donating effect of NC on V_O-MoO₂ can promote the dispersion of V_O-MoO₂ and reduce the bond energy of the Mo O bond, leading to exposure of active sites and enrichment of oxygen vacancies (V_O). Furthermore, the strong interfacial electrostatic interaction caused by the electron transfer from NC to V_O-MoO₂ can reduce the leaching of active sites of the catalyst. This study provides a versatile strategy of constructing strong electronic interaction between metal-oxide and support via anchoring on NC for the design of high-performance ODS catalysts.     

Quantification of Temperature-Dependent Charge Separation and Recombination Dynamics in Non-Fullerene Organic Photovoltaics

Transient optical spectroscopy is used to quantify the temperature-dependence of charge separation and recombination dynamics in P3TEA:SF-PDI₂ and PM6:Y6, two non-fullerene organic photovoltaic (OPV) systems with a negligible driving force and high photocurrent quantum yields. By tracking the intensity of the transient electroabsorption response that arises upon interfacial charge separation in P3TEA:SF-PDI₂, a free charge generation rate constant of ≈2.4 × 10¹⁰ s⁻¹ is observed at room temperature, with an average energy of ≈230 meV stored between the interfacial charge pairs. Thermally activated charge separation is also observed in PM6:Y6, and a faster charge separation rate of ≈5.5 × 10¹⁰ s⁻¹ is estimated at room temperature, which is consistent with the higher device efficiency. When both blends are cooled down to cryogenic temperature, the reduced charge separation rate leads to increasing charge recombination either directly at the donor-acceptor interface or via the emissive singlet exciton state. A kinetic model is used to rationalize the results, showing that although photogenerated charges have to overcome a significant Coulomb potential to generate free carriers, OPV blends can achieve high photocurrent generation yields given that the thermal dissociation rate of charges outcompetes the recombination rate.     

基于NB-IoT的智能烟感系统

传统的独立式烟感设备具有高成本,难以管理的技术痛点,已不再满足当下的消防需求。针对这样的问题,本文以实际应用需求为背景,开发设计了一款基于NB-IoT的智能烟感系统,集成Web系统端、移动APP端,降低管理和部署成本,提升管控效率,为“智慧城市”保驾护航。     

A review:Photonics devices,architectures,and algorithms for optical neural computing

The explosive growth of data and information has motivated various emerging non-von Neumann computational approaches in the More-than-Moore era.Photonics neuromorphic computing has attracted lots of attention due to the fascinating advantages such as high speed,wide bandwidth,and massive parallelism.Here,we offer a review on the optical neural computing in our research groups at the device and system levels.The photonics neuron and photonics synapse plasticity are presented.In addition,we introduce several optical neural computing architectures and algorithms including photonic spiking neural network,photonic convolutional neural network,photonic matrix computation,photonic reservoir computing,and photonic reinforcement learning.Finally,we summarize the major challenges faced by photonic neuromorphic computing,and propose promising solutions and perspectives.     

Peripheral Nerve‐Derived Matrix Hydrogel Promotes Remyelination and Inhibits Synapse Formation

Regeneration of injured nerve tissues requires intricate interplay of complex processes like axon elongation, remyelination, and synaptic formation in a tissue‐specific manner. A decellularized nerve matrix‐gel (DNM‐G) and a decellularized spinal cord matrix‐gel (DSCM‐G) are prepared from porcine sciatic nerves and spinal cord tissue, respectively, to recapitulate the microenvironment cues unique to the native tissue functions. Using an in vitro dorsal root ganglion–Schwann cells coculture model and proteomics analysis, it is confirmed that DNM‐G promotes far stronger remyelination activity and reduces synapse formation of the regenerating axons in contrast to DSCM‐G, Matrigel, and collagen I, consistent with its tissue‐specific function. Bioinformatics analysis indicates that the lack of neurotrophic factors and presence of some axon inhibitory molecules may contribute to moderate axonal elongation activity, while laminin β2, Laminin γ1, collagens, and fibronectin in DNM‐G promote remyelination. These results confirm that DNM‐G is a promising matrix material for peripheral nerve repair. This study provides more insights into tissue‐specific extracellular matrix components correlating to biological functions supporting functional regeneration.     

Stable Cycling of Phosphorus Anode for Sodium‐Ion Batteries through Chemical Bonding with Sulfurized Polyacrylonitrile

Sodium‐ion batteries are attracting increasing interests as a promising alternative to lithium‐ion batteries due to the abundant resource and low cost of sodium. Despite phosphorus (P) has extremely high theoretical capacity of 2595 mAh g^?1, its wide application for sodium‐ion battery is highly hampered by its fast capacity fading and low Coulombic efficiency as a result of large volume change upon cycling. Herein, a robust phosphorus anode with long cycle life for sodium‐ion battery via hybridization with functional conductive polymer is presented. To this end, the polyacrylonitrile is first dehydrogenated by sulfur via a facile thermal treatment, forming a conductive main chain embedded with C–S–S moieties. This functional conductive polymer enables the formation of P? S bonds between phosphorus and functional conductive matrix, leading to a robust electrode that can accommodate the large volume change upon substantial volume change in cycling. Consequently, this hybrid anode delivers a high capacity of ≈1300 mAh g^?1 at a current density of 520 mA g^?1 with high Coulombic efficiency (>99%) and good cycling performance (91% capacity retention after 100 cycles).     

如何避免雷电对民航电子设备的危害

雷电对电子设备的危害是无法估量的,各行业遭受雷电灾害的频率也越来越高,经济损失也在逐年增加,尤其是在民航领域多采用电子设备来运作,电子设备由于其特性容易受到雷电的入侵,造成机场电子设备的损坏甚至是瘫痪,会引发严重的后果,因此,有效避免雷电对电子设备的危害至关重要.基于此,本文主要分析了民航电子设备遭受雷电入侵的渠道和产生的危害,并且针对如何避免雷电对民航电子设备的危害提出相关解决措施来探讨和研究.     

Survey of outdoor and indoor architecture design in TVWS networks

To understand the utilizability of TV white spaces (TVWS), a comprehensive overview of the outdoor and indoor network design over TVWS is given. The related challenges are analyzed. The potential approaches to overcoming these challenges are discussed. The open research issues are investigated. The result shows that: in the indoor scenario, the white space ratio is on average 18.4% higher than that in the outdoor scenario, which corresponds to 7.7 vacant TV channels. Both network design includes 7 key components: TV spectrum identification, access point (AP) discovery, AP association, spectrum allocation, band width adaptation, interface control and disruption handling. Due to building penetration loss, the indoor TVWS identification and AP placement should be carefully considered in the indoor scenario.     

一种新颖的晶闸管串联均压的检验方法

为了改善由串联不均压引起的晶闸管失效问题,从晶闸管的选配和测试原理出发,详细分析了通态电流和器件温度等因素对串联选配的影响.提出了一种新颖的晶闸管串联均压的检验方法,并搭建了一个可以在一个周期中实现双电流测试,且温度可控的实验平台.该平台还具有人机互动功能,可以快速实现数据的采集和分析,方便了测试人员的操作,并大大提高了工作效率.经过现场满功率和未开满功率运行测试,均压系数与实验平台测试结果相似,验证了该方法的可靠性.该检验方法已应用于晶闸管中频电源选配中.