非均匀粘弹介质中有限元地震数字模型

本文讨论了粘弹介质的地震波响应。假定介质为块状,且块中纵,横波速度及密度、品质因数横向分段线性连续变化。在此条件下,给出了粘弹波动方程制作时间剖面的数学模型,导出了相应的有限元方程并给出其计算方法(包括刚度矩阵、阻尼矩阵)。模拟某实际水平叠加剖面的仿真结果,展示了该方法的效果和水平。     

5G下的应急广播

以5G技术为研究的出发点,探讨5G时代下应急广播技术的发展方向。同时,结合当前应急广播现状,分析了5G时代下应急广播的实践应用,给出了5G时代应急广播技术升级转型的意见和建议,为5G时代下应急广播发展和广泛应用提供可参考的思路。     

Locally Welded Silver Nano‐Network Transparent Electrodes with High Operational Stability by a Simple Alcohol‐Based Chemical Approach

As an indispensable aspect of emerging flexible optoelectronics, flexible transparent electrodes, especially those comprised of metal nanowires, have attracted great attentions recently. Welding the nanowire junctions is an effective strategy for reducing the sheet resistance and improving the operational stability of flexible nanowire electrode in practical applications. Herein, a simple alcohol‐based solution approach is proposed to weld crossed silver nanowires by chemically growing silver “solder” at the junctions of the nanowires, forming transparent silver nano‐network electrodes with improved electrical conductivity and operational stability. Remarkably, silver nano‐networks can be rapidly formed by this simple approach under ambient condition and room temperature, requiring no assistance from heat, light, electrical current, or mechanical pressure. Furthermore, our results show that the nano‐network electrode formed from large diameter nanowires offers a better operational stability, whose trend is opposite to that of the untreated electrodes. To demonstrate the potential application of the highly stable silver nano‐network from large diameter nanowires, organic solar cells fabricated on the nano‐network electrode incorporated with silicon dioxide nanoparticles achieve comparable performance to the ITO control device. Consequently, strategy demonstrated in this work can contribute to low‐cost and highly stable transparent electrodes in emerging flexible optoelectronics.     

一种星上资源动态分配的GSM网络扩展方案

在农村和偏远地区实现地面蜂窝网的覆盖成本高、代价大。iDirect Technologies提出通过卫星基于TDMA体制实现GSM网络的扩展,可以大大节省星上的带宽资源,为电信运营商对地面蜂窝网络的扩展提供了新的增长点。     

Euryhaline Hydrogel with Constant Swelling and Salinity-Enhanced Mechanical Strength in a Wide Salinity Range

In nature, many biological organisms possess a unique osmoregulation feature that enables them to survive in environments of different salinity, which is called euryhaline characteristics (e.g., salmon that can survive in freshwater and seawater). Drawing inspiration from these salinity-tolerant organisms, here a strategy that integrates two polymer chain segments with different salinity tolerances is reported to produce a euryhaline hydrogel with stable water retention, constant swelling properties, superoleophobicity, and low-adhesion to oil in aqueous environments over a wide range of salinity. The formation of internal dynamic complementary crosslinks is a key structural factor of the euryhaline attributes. The euryhaline hydrogel-coated meshes can be successfully utilized in various oil/aqueous phase separation in a wide range of salinity. Furthermore, by creating a double network with dynamic bonds, superior euryhaline hydrogel with unique salinity-enhanced mechanical strength can be obtained. It is anticipated that the euryhaline hydrogel will have broad application prospects in complex and variable ionic environments.     

红光LED尺寸对ITO电流扩展的影响

采用真空电子束蒸镀的方法制备氧化铟锡(ITO)薄膜,以此作为AlGaInP红光发光二极管(LED)的电流扩展层。研究了该LED结构中,不同的芯粒尺寸对ITO电流扩展的影响。结果表明,在电极尺寸一定的情况下,随着芯粒尺寸的变大,ITO电流扩展层对芯粒发光强度的变化起到显著的效果;在电极直径大小为90μm,芯粒尺寸为190μm×190μm时,电流扩展效果最优,亮度增加18.80%,而当芯粒尺寸增大到220μm×220μm时,亮度增加17.01%,其相对电流扩展效果下降。选取适当芯粒尺寸对ITO的电流扩展至关重要。     

Low-Cost Multi-Function Electrolyte Additive Enabling Highly Stable Interfacial Chemical Environment for Highly Reversible Aqueous Zinc Ion Batteries

The practicality of aqueous zinc ion batteries (AZIBs) for large-scale energy storage is hindered by challenges associated with zinc anodes. In this study, a low-cost and multi-function electrolyte additive, cetyltrimethyl ammonium bromide (CTAB), is presented to address these issues. CTAB adsorbs onto the zinc anode surface, regulating Zn²⁺ deposition orientation and inhibiting dendrite formation. It also modifies the solvation structure of Zn²⁺ to reduce water reactivity and minimize side reactions. Additionally, CTAB optimizes key physicochemical parameters of the electrolyte, enhancing the stability of the electrode/electrolyte interface and promoting reversibility in AZIBs. Theoretical simulations combined with operando synchrotron radiation-based in situ Fourier transform infrared spectra and in situ electrochemical impedance spectra further confirm the modified Zn²⁺ coordination environment and the adsorption effect of CTAB cations at the anode/electrolyte interface. As a result, the assembled Zn-MnO₂ battery demonstrates a remarkable specific capacity of 126.56 mAh g⁻¹ at a high current density of 4 A g⁻¹ after 1000 cycles. This work highlights the potential of CTAB as a promising solution for improving the performance and practicality of AZIBs for large-scale energy storage applications.     

The effect of IMU inaccuracies on airborne SAR imaging

When using motion compensation approaches based on the measurement of motion sensors, the residual uncompensated motion errors due to measurement instrument inaccuracies contribute to phase errors and hence degrade Synthetic Aperture Radar (SAR) images. This paper presents a model to compute the phase error caused by Inertial Measurement Unit (IMU) measurement inaccuracies. By analyzing SAR motion compensation method and the effect of lever arm, this model derives the contribution of each term of IMU inaccuracies towards the residual uncompensated motion errors and provides a method to calculate each order of the residual phase error. According to the model, computed results of the airborne X-band SAR system with POS AV510 accord closely with the actual image quality.     

热光Si共振腔型可调谐滤波器

报道了利用Si基键合技术和化学机械抛光工艺制作的垂直结构的Fabry- Perot可调谐滤波器,调谐机理为pn结正向注入电流引起的热光效应.调谐范围可达2 3nm,响应时间约为30 0 μs,并给出了获得更快响应和更低能耗的热光和电注入可调谐滤波器件结构改进方案.     

OFDM中频率同步的一种实现方案

频率同步是影响OFDM系统性能的一个很重要的问题。在分析现有的几种算法基础上,对频率跟踪、频率捕获和频域细同步进行了非常细致的研究,提出可行的频率同步方案。