Theoretical and Experimental Insight into the Mechanism for Spontaneous Vertical Growth of ReS2 Nanosheets

Rhenium disulfide (ReS₂) differs fundamentally from other group‐VI transition metal dichalcogenides (TMDs) due to its low structural symmetry, which results in its optical and electrical anisotropy. Although vertical growth is observed in some TMDs under special growth conditions, vertical growth in ReS₂ is very different in that it is highly spontaneous and substrate‐independent. In this study, the mechanism that underpins the thermodynamically favorable vertical growth mode of ReS₂ is uncovered. It is found that the governing mechanism for ReS₂ growth involves two distinct stages. In the first stage, ReS₂ grows parallel to the growth substrate, consistent with conventional TMD growth. However, subsequent vertical growth is nucleated at points on the lattice where Re atoms are “pinched” together. At such sites, an additional Re atom binds with the cluster of pinched Re atoms, leaving an under‐coordinated S atom protruding out of the ReS₂ plane. This under‐coordinated S is “reactive” and binds to free Re and S atoms, initiating growth in a direction perpendicular to the ReS₂ surface. The utility of such vertical ReS₂ arrays in applications where high surface‐to‐volume ratio and electric‐field enhancement are essential, such as surface enhanced Raman spectroscopy, field emission, and solar‐based disinfection of bacteria, is demonstrated.     

Hybrid 2D Dual‐Metal–Organic Frameworks for Enhanced Water Oxidation Catalysis

Metal–organic frameworks (MOFs) and MOF‐derived nanostructures are recently emerging as promising catalysts for electrocatalysis applications. Herein, 2D MOFs nanosheets decorated with Fe‐MOF nanoparticles are synthesized and evaluated as the catalysts for water oxidation catalysis in alkaline medium. A dramatic enhancement of the catalytic activity is demonstrated by introduction of electrochemically inert Fe‐MOF nanoparticles onto active 2D MOFs nanosheets. In the case of active Ni‐MOF nanosheets (Ni‐MOF@Fe‐MOF), the overpotential is 265 mV to reach a current density of 10 mA cm^?2 in 1 m KOH, which is lowered by ≈100 mV after hybridization due to the 2D nanosheet morphology and the synergistic effect between Ni active centers and Fe species. Similar performance improvement is also successfully demonstrated in the active NiCo‐MOF nanosheets. More importantly, the real catalytic active species in the hybrid Ni‐MOF@Fe‐MOF catalyst are unraveled. It is found that, NiO nanograins (≈5 nm) are formed in situ during oxygen evolution reaction (OER) process and act as OER active centers as well as building blocks of the porous nanosheet catalysts. These findings provide new insights into understanding MOF‐based catalysts for water oxidation catalysis, and also shed light on designing highly efficient MOF‐derived nanostructures for electrocatalysis.     

Sub-Nanowires Boost Superior Capacitive Energy Storage Performance of Polymer Composites at High Temperatures

Polymer dielectrics with high breakdown strength (E_b) and high efficiency are urgently demanded in advanced electrical and electronic systems, yet their energy density (U_e) is limited due to low dielectric constant (ε_r) and high loss at elevated temperatures. Conventional inorganic fillers with diameters from nano to micrometers can only increase ε_r at the cost of compromised E_b and U_e due to their poor compatibility with polymer matrix. Herein, hydroxyapatite (HAP) sub-nanowires with a diameter of ≈0.9 nm are incorporated in polyetherimide (PEI) matrix to form HAP/PEI sub-nanocomposites. ε_r and E_b of the composites are concomitantly enhanced with only 0.5 wt.% of HAP sub-nanowires, leading to high U_e of 5.14 (@150 °C) and 3.1 J cm⁻³ (@200 °C) with efficiency of 90% and high-temperature stability up to 3 × 10⁵ charge-discharge cycles at 200 °C. Microstructural analysis and molecular dynamics simulations indicate that the sub-nanowires with comparable diameter as polymer chains induce enormous interfacial area, substantially increase mobility of polymer chains and form dense traps for charge carriers. This work extends the current research scope of polymer-inorganics composite dielectrics to the sub-nano-level incorporation and provides a novel strategy for fabricating high performance polymer dielectrics at elevated temperatures.     

Field-Induced Multiscale Polarization Configuration Transitions of Mesentropic Lead-Free Piezoceramics Achieving Giant Energy Harvesting Performance

The development of high-performance (K,Na)NbO₃ (KNN)-based lead-free piezoceramics for next-generation electronic devices is crucial for achieving environmentally sustainable society. However, despite recent improvements in piezoelectric coefficients, correlating their properties to underlying multiscale structures remains a key issue for high-performance KNN-based ceramics with complex phase boundaries. Here, this study proposes a medium-entropy strategy to design “local polymorphic distortion” in conjunction with the construction of uniformly oversize grains in the newly developed KNN solid-solution, resulting in a novel large-size hierarchical domain architecture (≈0.7 µm wide). Such a structure not only facilitates polarization rotation but also ensures a large residual polarization, which significantly improves the piezoelectricity (≈3.2 times) and obtains a giant energy harvesting performance (W_out = 2.44 mW, P_D = 35.32 µW mm⁻³, outperforming most lead-free piezoceramics). This study confirms the coexistence of multiphase through the atomic-resolution polarization features and analyzes the domain/phase transition mechanisms using in situ electric field structural characterizations, revealing that the electric field induces highly effective multiscale polarization configuration transitions based on T–O–R sequential phase transitions. This study demonstrates a new strategy for designing high-performance piezoceramics and facilitates the development of lead-free piezoceramic materials in energy harvesting applications.     

Understanding of Delamination Mechanism of Anisotropic Conductive Film (ACF) Bonding in Thin Liquid Crystal Display (LCD) Module

The chip-on-glass (COG) technique using anisotropic conductive film (ACF) has been developed for liquid crystal display (LCD) panels with excellent resolution and high quality for several years. However, many serious manufacturability and reliability issues were observed from previous studies. In those, delamination occurring at the ACF interface is one of the common concerns. Few works presented analysis of delamination mechanism through the whole COG bonding process with the combination of LCD module scale and ACF interconnect scale. In this paper, the delamination mechanism of COG/ACF interconnection was studied by using finite element analysis. Equivalent block and global-local modeling methods were implemented with nonlinear elastic-plastic and sequential coupled thermal-mechanical analysis. The critical parameters of the COG bonding process and geometry of integrated circuit (IC) and glass were investigated to understand the mechanism of ACF delamination. It was found that the delamination could be reduced by decreasing the temperature difference between bonding head and glass substrate or using thin and short IC. The local model analysis revealed that the interface of glass/ACF epoxy encountered the higher stress than that in the interface of IC/ACF epoxy and had the higher possibility to delaminate. Therefore, increasing the bonding-strength between glass and ACF epoxy is the direction to reduce the probability of ACF delamination.     

Model-based adaptive resolution upconversion of degraded images

Resolution upconversion of a degraded image is an ill-posed inverse problem that is even harder than video superresolution due to lack of redundant observations from reference frames. To overcome this difficulty an adaptive 2D piecewise autoregressive (PAR) model is used to strengthen the constraints on the solution of the inverse problem. The PAR model can be fit to local image waveforms by adjusting its parameters. But estimating the model parameters needs the knowledge of the very original high-resolution pixels to be estimated by the model. We resolve this chicken-and-egg dilemma by adaptive nonlinear least-squares joint estimation of both model parameters and original pixels. This non-linear estimation problem is solved by the method of structured total least-squares, constrained by the degradation function (e.g., the point spread function of a camera plus noises) that forms the observed low-resolution image. As such, this work offers a unified general framework for joint upsampling, deconvolution, and denoising. Moreover, the upsampling can be carried out at an arbitrary scale rather than power of two. Experiments show that the proposed NEARU technique outperforms current methods in both PSNR and subjective visual quality, and its advantage becomes greater for larger scaling factors.     

Low power flexible organic thin film transistors with amorphous Ba0.7Sr0.3TiO3 gate dielectric grown by pulsed laser deposition at low temperature

We deposited amorphous Ba_0.7Sr_0.3TiO₃ (BST) on silicon and plastic substrate under 110 °C by pulsed laser deposition (PLD) and use it as the dielectric of the organic transistor. Depends on the thickness of BST layer, the highest mobility of the devices can achieve 1.24 cm² V^?1 s^?1 and 1.01 cm² V^?1 s^?1 on the silicon and polyethylene naphthalate (PEN) substrate, respectively. We also studied the upward and downward bending tests on the transistors and the dielectric thin films. We found that the BST dielectric pentacene transistor can maintain the mobility at 0.5 cm² V^?1 s^?1 or higher while the bending radius is around 3 mm in both upward and downward bending. Our finding demonstrates the potential application of PLD growth high-k dielectric in the large area organic electronics devices.     

卫星定位中伪距的广义延拓外推

GPS当丢失部分伪距不能正常定位时,采用广义延拓外推法外推伪距来实现对用户位置的定位.仿真结果和理论推理表明,这种伪距外推法在外推步数一定的条件下能满足用户接收机定位的要求.     

激光干扰对红外成像探测器MTF影响的仿真研究

分析了激光辐照对成像探测器的软损伤效应,尤其是成像探测器光学性能的退化效应.通过探测器仿真软件模拟了激光辐照前后的斜缝成像效果,并使用二维傅里叶变换法获得了辐照前后的系统MTF值,证明了激光辐照对MTF的影响.     

红外雷达复合隐身技术探讨

简要介绍了目前红外、雷达隐身技术的现状和存在的问题,并对国外目前研究的掺杂氧化物半导体材料、导电聚合物、视黄基席大碱盐、涂覆金属空心导电微珠和纳米吸波材料等新型红外雷达兼容隐身材料进行了详细探讨,最后沦述了红外雷达复合隐身涂层技术的隐身机理和发展现状.