Dopant Diffusion Equilibrium Overcoming Impurity Loss of Doped QDs for Multimode Anti-Counterfeiting and Encryption

High ion diffusivity of Cu⁺ dopants accelerates outdiffusion in quantum dots (QDs) at high temperatures. This kind of self-purification gives rise to a sharp decrease in dopant photoluminescence (PL) intensity. Herein, a dopant diffusion equilibrium strategy is developed by introducing extra Cu⁺ in the epitaxial growth process. By preventing the loss of dopant Cu⁺, both the decrease of dopant PL and increase of band-edge PL intensity are successfully suppressed. The coexistence of visible and invisible near-infrared (NIR) PL bands for Cu-doped CdSe@CdS QDs demonstrates their novel multimode anti-counterfeiting/encryption potential. Via printing by combined using of intrinsic and doped QD “inks” with visible and invisible NIR emissions, respectively, the bulk-sized patterns, texts, and numerals can achieve visible–invisible PL synergetic confidential information multimode anti-counterfeiting and encryption.     

Ultrafast Electrochemical Growth of Lithiophilic Nano-Flake Arrays for Stable Lithium Metal Anode

Lithium dendrites caused by nonuniform Li⁺ flux leads to the capacity fade and short-circuit hazard of lithium metal batteries. The solid electrolyte interface (SEI) is critical to the uniformity of Li⁺ flux. Here, an ultrafast preparation of uniform and vertical Cu₇S₄ nano-flake arrays (Cu₇S₄ NFAs) on the Cu substrate is reported. These arrays can largely improve the lithiophilicity of the anode and form Li₂S-enriched SEI due to the electrochemical reduction of Cu₇S₄ NFAs with lithium. A further statistical analysis suggests that the SEI, with a higher content of Li₂S, is more effective to inhibit the formation of lithium dendrites and yields less dead lithium. A quite stable coulombic efficiency of 98.6% can be maintained for 400 cycles at 1 mA cm^–2. Furthermore, at negative to positive electrode capacity ratio of 1.5 (N/P = 1.5), the full battery of Li@Cu₇S₄ NFAs||S shows 83% capacity retention after 100 cycles at 1 C, much higher than that of Li@Cu||S (33%). The findings demonstrate that high Li₂S content in the SEI is crucial for the dendrite inhibition to achieve better electrochemical performance.     

3D Porous Honeycomb-Like CoN-Ni3N/N-C Nanosheets Integrated Electrode for High-Energy-Density Flexible Supercapacitor

Transition metal nitrides (TMNs) are considered as potential electrode materials for high-performance energy storage devices. However, the structural instability during the electrochemical reaction process severely hinders their wide application. A general strategy to overcome this obstacle is to fabricate nanocomposite TMNs on the conducting substrate. Herein, the honeycomb-like CoN-Ni₃N/N-C nanosheets are in situ grown on a flexible carbon cloth (CC) via a mild solvothermal method with post-nitrogenizing treatment. As an integrated electrode for the supercapacitor, the optimized CoN-Ni₃N/N-C/CC achieves remarkable electrochemical performance due to the enhanced intrinsic conductivity and increased concentration of the active sites. In particular, the flexible quasi-solid-state asymmetric supercapacitor assembled with CoN-Ni₃N/N-C/CC cathode and VN/CC anode delivers an excellent energy density of 106 μWh cm⁻², maximum power density of 40 mW cm⁻², along with an outstanding cycle stability. This study provides a neoteric perspective on construction of high-performance flexible energy storage devices with novel metallic nitrides.     

Hierarchically Responsive Tumor-Microenvironment-Activated Nano-Artificial Virus for Precise Exogenous and Endogenous Apoptosis Coactivation

Targeting apoptotic pathways in tumor cells is recognized as a potent anticancer strategy. However, monotherapies that target a single apoptotic pathway often do not meet expectations and the nonspecific and uncontrolled activation of apoptotic pathways can overshadow potential application prospects. Here, a novel tumor-microenvironment-activated nano-artificial virus (TMAN) with hierarchically responsive capacity is fabricated and loaded with the plasmid encoding tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and mitochondria-targeted red fluorescent phototoxic protein (KillerRed) simultaneously for precise and controllable exogenous and endogenous apoptosis coactivation. The inert TMAN is endowed with in vivo longevity and undergoes orderly acidity-triggered deshielding of a masking layer, enzyme-responsive charge-reversal, and oxidative stress-sensitive structural fragmentation in the tumor extra/intracellular microenvironment to exert precise tumor recognition, deep penetration, cellular internalization, rapid endosomes escape, and effective gene release ability, leading to the effective and tumor-specific delivery of payloads. Given the virtues of TMAN, a favorable collaboration of TRAIL-triggered exogenous apoptosis and mitochondria-targeted KillerRed induced endogenous apoptosis is achieved synchronously under the control of light irradiation, thus remarkably improving antitumor efficacy with minimal toxicity. Taken together, this strategy highlights the significance of exogenous and endogenous apoptosis coactivation in cancer treatments and offers a promising paradigm for precise exo/endogenous dual-augmented antitumor therapy.     

Computational Studies on Carbon Dots Electrocatalysis: A Review

Electrocatalytic reactions possess wide application prospects in solving the energy crisis. Recently, the emerging 0D carbon dots (CDs) have become potential candidate materials due to their low cost, high conductivity, easy modification, and simple synthesis. CDs-based composite materials showcase attractive electrocatalytic performances because of the abundant active sites and charge distribution on the material surface. Considering the complicated structure of CDs, it's important to identify the specific catalytic activity source and understand catalytic mechanisms with the aid of theoretical method. In this review, the latest advancements are presented on improving the electrocatalytic activity and stability of CDs-based composite materials from theoretical perspective. Meanwhile, the opportunity and challenges about developing high-performance CDs catalysts are also highlighted.     

6.5 kV SiC光控晶闸管的研制

基于Sentaurus TCAD软件,研制了一款6.5 kV SiC光控晶闸管.通过优化雪崩击穿模型,对多层外延材料的规格及渐变终端技术进行研究,有效抑制了芯片表面峰值电场,实现了6.5 kV的耐压设计;此外结合实际应用需求,对器件的开通特性进行了仿真模拟.在4英寸(1英寸=2.54 cm)SiC工艺平台制备了6.5 kV SiC光控晶闸管,并对器件性能进行了测试.测试结果显示,芯片击穿电压超过6.5 kV,在4 kV电源电压以及365 nm波长紫外光触发的条件下,器件导通延迟约为200 ns,脉冲峰值电流约为2.1 kA,最大导通电流变化率(di/dt)达到6.3 kA/μs,测试结果与仿真模拟结果基本一致.     

基于智慧课堂的"传感器原理及应用"混合式教学探讨研究

本文分析了"传感器原理及应用"课程教学过程中存在的问题,在教学大纲体系优化、教学方式和教学组织模式等三方面提出了一些改革性的建议,结合项目式教学提出了基于智慧课堂的混合式教学方式.     

Targeted transfer of self-assembled CdSe nanoplatelet film onto WS2 flakes to construct hybrid heterostructures

Colloidal CdSe nanoplatelets are thin semiconductor materials with atomic flatness surfaces and one-dimensional strong quantum confinement,and hence they own very narrow and anisotropic emission.Here,we present a polydimethylsilox-ane(PDMS)assisted transferring method that can pick up single layer CdSe nanoplatelet films self-assembled on a liquid sur-face and then precisely transfer to a target.By layer-by-layer picking up and transferring,multiple layers of CdSe films can be built up to form CdSe stacks with each single layer having dominant in-plane transition dipole distribution,which both materi-al and energic structures are analogous to traditional multiple quantum wells grown by molecular-beam epitaxy.Additionally,with the great flexibility of colloidal nanoplatelets and this transferring method,CdSe nanoplatelets films can be combined with other materials to form hybrid heterostructures.We transferred a single-layer CdSe film onto WS2 flakes,and precisely stud-ied the fast energy transfer rate with controlled CdSe nanoplatelet orientation and by using a streak camera with a ps time resol-ution.     

Faster-than-Nyquist Transmission in SC-FDE System Over Frequency Selective Channel with Concatenated Equalizers

The trustworthiness and connectivity of the network depends on the energy drain rate of mobile nodes. Colluders like vampire nodes in ad hoc network make it more vulnerable as they rapidly drain considerable amount of energy. This generic vampire attacks seem to capitalize on the potential features of the incorporated baseline protocol used for facilitating trustworthy data dissemination. The main goal of this paper is to formulate an attack prevention scheme that uses fuzzy trust relationship perspective for detecting vampire attacks and enforcing reduced energy drain rate of colluding mobile nodes. This fuzzy trust relationship perspective-based prevention mechanism (FTRPPM) initially estimates the associative trust and associative reputation of mobile nodes. Further, it quantifies the impact of factors that could induce vampire attack in the network under its influence. Finally, it facilitates the detection of vampire nodes based on the established ranges of threshold that are dynamically adjusted based on quantified level of probability factor. The empirical and simulation results of FTRPPM is confirmed to be exceptional as it ensures a remarkable improvement in mean PDR of 16% and mean throughput of 14% under the impact of increasing number of mobile nodes on par with the existing vampire attack mitigation schemes.     

Washable Multilayer Triboelectric Air Filter for Efficient Particulate Matter PM2.5 Removal

Efficient removal of particulate matter (PM) is the major goal for various air cleaning technologies due to its huge impact on human health. Here, a washable high‐efficiency triboelectric air filter (TAF) that can be used multiple times is presented. The TAF consists of five layers of the polytetrafluoroethylene (PTFE) and nylon fabrics. Compared with traditional electrostatic precipitator, which requires a high‐voltage power supply, the TAF can be charged by simply rubbing the PTFE and nylon fabrics against each other. The electrical properties of the TAF are evaluated through the periodic contacting–separating of the PTFE and nylon fabrics using a linear motor, and an open‐circuit voltage of 190 V is achieved. After charging, the TAF has a removal efficiency of 84.7% for PM_0.5, 96.0% for PM_2.5, which are 3.22 and 1.39 times as large as the uncharged one. Most importantly, after washing several times, the removal efficiency of the TAF maintains almost the same, while the commercial face mask drops to 70% of its original efficiency. Furthermore, the removal efficiency of the PM_2.5 is very stable under high relative humidity. Therefore, the TAF is promising for fabricating a reusable and high‐efficiency face mask.