Hierarchical Composite-Solid-Electrolyte with High Electrochemical Stability and Interfacial Regulation for Boosting Ultra-Stable Lithium Batteries

Solid-state electrolytes have drawn enormous attention to reviving lithium batteries but have also been barricaded in lower ionic conductivity at room temperature, awkward interfacial contact, and severe polarization. Herein, a sort of hierarchical composite solid electrolyte combined with a “polymer-in-separator” matrix and “garnet-at-interface” layer is prepared via a facile process. The commercial polyvinylidene fluoride-based separator is applied as a host for the polymer-based ionic conductor, which concurrently inhibits over-polarization of polymer matrix and elevates high-voltage compatibility versus cathode. Attached on the side, the compact garnet (Li_6.4La₃Zr_1.4Ta_0.6O₁₂) layer is glued to physically inhibit the overgrowth of lithium dendrite and regulate the interfacial electrochemistry. At 25 °C, the electrolyte exhibits a high ionic conductivity of 2.73 × 10⁻⁴ S cm⁻¹ and a decent electrochemical window of 4.77 V. Benefiting from this elaborate electrolyte, the symmetrical Li||Li battery achieves steady lithium plating/stripping more than 4800 h at 0.5 mA cm⁻² without dendrites and short-circuit. The solid-state batteries deliver preferable capacity output with outstanding cycling stability (95.2% capacity retained after 500 cycles, 79.0% after 1000 cycles at 1 C) at ambient temperature. This hierarchical structure design of electrolyte may reveal great potentials for future development in fields of solid-state metal batteries.     

基于北斗三号卫星非差多普勒观测信号的优化测速模型

针对运动载体速度估计方法精度不足、模型复杂等问题,提出了一种精度高、模型复杂度低的基于北斗三号卫星非差多普勒观测信号的优化测速模型。该模型利用北斗三号卫星原始数据,使用复杂度低的多普勒测速模型估计载体速度。为提高测速精度和解算效率,首先对原始模型线性化处理,然后依据载体航向与其速度矢量的相关性增加松约束。用北斗三号卫星实测数据验证了该模型的测速精度,评估了该模型的适用性。实验结果表明,载体静止时,优化多普勒测速精度可达cm/s级甚至mm/s级,在与原始多普勒测速的对比中,水平方向测速精度提高60%左右,解算时间缩短24%;载体运动时,增加航向约束的多普勒测速精度与原始多普勒测速相比,北、东方向测速精度可提高14%～21%,解算效率提升大约20%。     

Vanadium Doping Enhanced Electrochemical Performance of Molybdenum Oxide in Lithium‐Ion Batteries

Molybdenum trioxide (MoO₃) suffers from poor conductivity, a low rate capability, and unsatisfactory cycling stability in lithium‐ion batteries. The aliovalent ion doping may present an effective way to improve the electrochemical performances of MoO₃. Here, it is shown, by first‐principle calculations, that doping MoO₃ with V by 12.5% can modulate significantly electronic structure and provide a small diffusion barrier for enhancing the electrochemical performance of MoO₃. The ultralong Mo_0.88V_0.12O_2.94 nanostructures, which retain the h‐MoO₃ structure and present an exceptionally high conductivity and fast ionic diffusion due to the substitution of V, facilitating lithiation/delithiation behavior, and induce a fine nanosized structure with a reduced volume change are prepared. As a result, the stress and strain are alleviated during the Li‐ion intercalation/deintercalation processes, improving the cycling stability and rate capability. Such a large improvement in the electrochemical properties can be ascribed to the stabilizing effect of V, the small migration energy barrier, and short diffusion path, which arise from the introduction of V into MoO₃. The unique engineering strategy and facile synthesis route open up a new avenue in modifying and developing other species of electrode materials.     

肿瘤多细胞球:一种近似实体瘤的体外肿瘤模型

本文介绍了一种简便易行的方法,用以在体外建立近似体内实体瘤的肿瘤模型—肿瘤多细胞球模型(multicellular tumor spheroids,MCTSs).采用液滴重叠法(liquid overlay method)来构建HeLa肿瘤多细胞球模型,并在光镜下对肿瘤多细胞球的生长状况进行观察描述,再应用场发射扫描电...     

基于S3C2440的测试系统数字稳压电源设计

通过对所需求电源的分析,结合嵌入式控制技术,提出了一种基于S3C2440的测试系统数字稳压电源解决方案,以及实现该方案所采用的方法。该系统基于ARM控制技术,对数据进行采样,运用适当的算法进行电压调节和电路保护,以达到为测试系统提供稳压电源的目的。设计的系统经过实际应用,所提供的电源稳定可靠,满足芯片测试所需电源的要求。在此给出了系统的硬件构架和软件设计流程图。     

Tunable Crystallinity in Regioregular Poly(3‐Hexylthiophene) Thin Films and Its Impact on Field Effect Mobility

The properties of poly(alkylthiophenes) in solution are found to have a profound impact on the self assembly process and thus the microstructural and electrical properties of the resultant thin films. Ordered supramolecular precursors can be formed in regioregular poly(3‐hexylthiophene) (P3HT) solutions through the application of low intensity ultrasound. These precursors survive the casting process, resulting in a dramatic increase in the degree of crystallinity of the thin films obtained by spin coating. The crystallinity of the films is tunable, with a continuous evolution of mesoscale structures observed as a function of ultrasonic irradiation time. The photophysical properties of P3HT in solution as well in the solid state suggest that the application of ultrasound leads to a π stacking induced molecular aggregation resulting in field effect mobilities as high as 0.03 cm² V^?1 s^?1. A multiphase morphology, comprising short quasi‐ordered and larger, ordered nanofibrils embedded in a disordered amorphous phase is formed as a result of irradiation for at least 1 min. Two distinct regions of charge transport are identified, characterized by an initial sharp increase in the field effect mobility by two orders of magnitude due to an increase in crystallinity up to the percolation limit, followed by a gradual saturation where the mobility becomes independent of the thin film microstructure.     

Time‐of‐Flight Studies of Electron‐Collection Kinetics in Polymer:Fullerene Bulk‐Heterojunction Solar Cells

The charge‐collection dynamics in poly(3‐hexylthiophene:[6,6]‐phenyl‐C₆₁‐butyric acid methyl ester (P3HT:PCBM) bulk heterojunctions are studied in thick (>1 μm) devices using time‐of‐flight measurements and external quantum‐efficiency measurements. The devices show Schottky‐diode behavior with a large field‐free region in the device. Consequently, electron transport occurs by diffusion in the bulk of the active layer. At high applied biases where the depletion region spans the entire active layer, normal time‐of‐flight transients are observed from which the electron mobility can be determined. Here, the electron mobility follows Poole–Frenkel behavior as a function of field. At lower applied biases, where the depletion region only spans a small portion of the active layer, due to a high density of dark holes, the recombination kinetics follow a first‐order rate law with a rate constant about two orders of magnitude lower than that predicted by Langevin recombination.     

Improvement on low-temperature deposited HfO2 film and interfacial layer by high-pressure oxygen treatment

In this study, high-pressure oxygen (O₂ and O₂ + UV light) technologies were employed to effectively improve the properties of low-temperature-deposited metal oxide dielectric films and interfacial layer. In this work, 13 nm HfO₂ thin films were deposited by sputtering method at room temperature. Then, the oxygen treatments with a high-pressure of 1500 psi at 150 °C were performed to replace the conventional high temperature annealing. According to the XPS analyses, integration area of the absorption peaks of O-Hf and O-Hf-Si bonding energies apparently raise and the quantity of oxygen in deposited thin films also increases from XPS measurement. In addition, the leakage current density of standard HfO₂ film after O₂ and O₂ + UV light treatments can be improved from 3.12 × 10⁻⁶ A/cm² to 6.27 × 10⁻⁷ and 1.3 × 10⁻⁸ A/cm² at |Vg| = 3 V. The proposed low-temperature and high pressure O₂ or O₂ + UV light treatment for improving high-k dielectric films is applicable for the future flexible electronics.     

On the mechanisms limiting mobility in InP/InGaAs buried channel nMISFETs

MISFETs incorporating the InP/InGaAs buried channel showed a high peak mobility of 5500 cm²/V s. Spillover of the inversion carriers from the buried channel to the MIS interface on the InP barrier layer caused drastic mobility degradation as the carrier concentration was increased. The spillover was evidenced by observing a negative transconductance and a kink in split capacitance-voltage curves. Remote scattering by the trapped charges at the MIS interface also reduced the mobility when the InP barrier layer was as thin as 2 nm.     

先进制造技术在大型艺术制像中的应用研究

本文通过海南南山三面观音圣像(108米)的设计实例,论述了反向工程、计算机辅助设计、计算机辅助检测等先进制造技术在大型金属艺术制像中的应用,并介绍了ATOS便携式三维扫描仪及反向工程软件Imageware的工作原理.