Unraveling the Origin of Enhanced K+ Storage of Carbonaceous Anodes Enabled by Nitrogen/Sulfur Co-Doping

N-doped carbons, as promising anode materials for energy storage, are generally modified by the additional heteroatoms (B, P, and S) doping to further promote the electrochemical performance. However, the promotion mechanism by such additional doping, especially its interplay with N-containing species, remains unclear. Herein, by adopting N/S co-doped carbon as a model system, it is found that S-doping can significantly improve the content of pyridinic-N, i.e., the most energetically favorable N type for K⁺ storage. Theoretical calculations reveal that such S-induced pyridinic-N improvement possibly originates from its catalytic effect that can facilitate the transition from edge quaternary-N to pyridinic-N. The resultant high content of pyridinic-N, together with the additional S species, ensures abundant active sites for K⁺ storage. Accordingly, the N/S co-doped carbon anode delivers both a high reversible capacity (422.9 mA h g⁻¹ at 0.05 A g⁻¹) and an impressive cyclic stability (249.6 mA h g⁻¹ at 1 A g⁻¹ over 4000 cycles). Moreover, in/ex situ characterizations further verify the merits of N/S co-doped carbon from the perspective of compositional evolution and structural stability. This study unravels the origin of enhanced K⁺ storage by N/S co-doping, which also helps to understand the synergistic effects of other heteroatoms co-doping systems.     

Macro-Sized All-Graphene 3D Structures via Layer-by-Layer Covalent Growth for Micro-to-Macro Inheritable Electrical Performances

Creating 3D-engineered macroscopic architectures while inheriting the superior properties of individual building blocks remains one of the fundamental challenges in nanotechnology. Stable covalent interconnection between micro/nanoblocks is a desired but underexplored strategy to meet the challenges, rather than current dependently-used weak physical forces or organic cross-linking, which disrupts the continuity of chemical composition and electrical properties. Herein, a novel layer-by-layer covalent growth protocol is developed to construct all-graphene macrostructures (AGM) with micro-to-macro inheritable electrical properties by laser-assisted covalent linkage of polyethersulfone-derived 3D porous graphene microblocks without introducing any catalysts, templates, and additives. Creatively, along with graphene generation and inter-layer bonding, a quality optimization process is integrated into one-step laser irradiation, which is unique and efficient for synthesizing high-crystalline graphene. With the covalently nondestructive bridge and free of non-graphene foreign phase impurities, AGM shows unprecedented electrical conductivity, especially a more than 100-fold improvement in cross-layer conductivity compared with non-covalent assembly. Furthermore, the covalent growth mechanism of AGM is clarified by molecular dynamics simulations. Finally, the application efficacy of AGM with enhanced isotropic conductivity is verified by using it as a supercapacitor electrode. This methodology enables the as-obtained AGM to possess the potential for high-performance-pursuing, multi-disciplinary, or large-scale applications.     

The Localized-SOI MOSFET as a Candidate for Analog/RF Applications

In this paper, the characteristics of a localized-SOI (L-SOI) MOSFET are investigated for analog/RF applications. In the L-SOI device, the source/drain regions are quasi-surrounded by L-type oxide layers to reduce junction capacitance and avoid source/drain punchthrough, while the channel is directly connected with the substrate to alleviate the self-heating effect. Such structures can combine the advantages of both bulk and SOI MOSFETs and avoid their issues. Due to the unique structure of this novel device, the L-SOI MOSFET can exhibit excellent analog/RF behaviors. Higher g _m / I _ds ratio and intrinsic gain (g _m / g _ds)can be received compared with the conventional SOI structure, particularly at low gate bias. Higher and , which are due to higher g _m and reduced gate capacitance, can be observed in the L-SOI MOSFET. In addition, better noise performance can be achieved resulting from reduced lattice temperature and improved g _m . Thus, the L-SOI MOSFET can be considered as one of the potential candidates for analog/RF 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.     

相关扩展K-分布雷达杂波及其仿真分析

针对雷达杂波具有尖峰、非对称和重拖尾等非高斯特征,使用二元Rayleigh独立积和自由度为n的广义x~2分布的随机变量进行级联,得到扩展K-分布随机变量。二元Rayleigh独立积使得扩展K-分布比K-分布在概率密度函数上具有更为明显的尖峰和重拖尾,且二元Rayleigh独立积的出现与高分辨率雷达杂波的散射机制相符。使用Markov扩散过程模型产生相关的扩展K-分布杂波随机变量。仿真得到的随机序列的概率密度分布与理论值吻合很好。     

一种新型的在线式微波功率传感器

提出了一种基于MEMS技术的在线式微波功率传感器结构,并对该结构进行了理论分析、设计、制作和测量.该结构通过测量由MEMS膜耦合出的一小部分微波功率实现功率的测量.该结构制作工艺与GaAs MMIC工艺完全兼容.测量结果显示,在12GHz频率以内,微波功率传感器的反射系数小于-15dB,插入损耗小于2dB,在10GHz中心频率下的灵敏度为10 4μV/mW.     

采用铟束流保护下的调制中断生长技术改善(0001)GaN表面形貌

使用分子束外延方法,采用In束流保护下的调制中断生长技术,在(0001)蓝宝石衬底上生长GaN薄膜.利用反射式高能电子衍射(RHEED)对生长进行实时监控,并用扫描电子显微镜(SEM)、原子力显微镜(AFM)和X射线衍射(XRD)法对GaN外延薄膜的表面形貌和晶体质量进行分析.实验结果表明:采用该技术生长的Ga极性GaN外延薄膜中的晶体表面残留Ga滴密度大大降低,GaN外延薄膜的表面形貌得到改善,其均方根粗糙度(RMS)由3nm降低为0.6nm,同时XRD双晶摇摆曲线测试的结果表明,GaN外延层的晶格质量也得到改善.     

Design and Fabrication of a High-Voltage nMOS Device

High-voltage nMOS devices are fabricated successfully and the key technology parameters of the process are optimized by TCAD software.Experiment results show that the device’s breakdown voltage is 114V,the threshold voltage and maximum driven ability are 1.02V and 7.5mA(W/L=50),respectively.Experimental results and simulation ones are compared carefully and a way to improve the breakdown performance is proposed.     

一种基于ECDSA的USB存储设备访问控制方案

文章针对使用USB存储设备造成的内部泄密问题,提出了一种USB存储设备访问控制方案,该方案对用户的身份认证基于安全强度很高的椭圆曲线数字签名算法,同时使用过滤器驱动程序实现了USB存储设备的读写控制,因而此方案具有较好的安全性、实用性和通用性。     

通信设备厂商并购产业重组潮流涌动

现象揭示着规律,面对已不算新闻的爱立信-马可尼、阿尔卡特-朗讯、诺基亚-西门子三起通信设备厂商并购案,什么样的思考方能正解通信产业的变迁？也许这数起并购是通信产业重组潮流中的过去时．是进行时,也是将来时。邀请阚凯力、陈金桥、曾剑秋、陈育平、张薇及邓志成先生等知名业内人士一道聚焦这几起并购,《世界电信》与您一起思考。