一种基于实时几何测距的船桥主动防撞方法

本文提出一种基于实时几何测距的船桥主动防撞方法.该方法对船的改动量甚微,仅需维持多项距离矩阵,通过告警逻辑矩阵进行展示与告警,能起到很好的船桥防撞提示效果.     

基于“互联网+”视阈下的信息安全防范

在"互联网+"时代背景下,暴露在互联网上的任何终端、服务器、云主机、路由器等设备设施,只要接入到互联网必将面临来自外部网络环境的各种安全威胁。网络黑客攻击、网络病毒泛滥、网络爬虫风险和网络业务需求,悄然构成了对信息安全防范的迫切需要。文章对现有网络安全威胁以及表现形式客观分析,就加强信息安全应对防范措施做了讨论探析,并描述了本研究领域前沿发展趋势。     

壳层隔绝纳米粒子增强拉曼光谱测试系统设计

基于壳层隔绝纳米粒子增强技术,开发了一种新型的等离激元拉曼光谱测试系统,该系统能够有效地提高被测物质的拉曼反射信号强度。壳层隔绝纳米粒子增强技术采用包裹了极薄的二氧化硅或者氧化铝壳层的单层金纳米粒子,能够产生较强的表面增强效应。整个测试系统的硬件部分主要包括双处理器（ARM和DSP）主控板、半导体激光光源、光谱仪、光纤探头和粒子施加装置;软件部分能够自动获取被测物质的拉曼谱图。这里,粒子施加装置用于自动地将壳层隔绝纳米粒子施加到被测样本中。在实验中,将测试系统用于检测食品违禁添加物三聚氰胺和孔雀石绿,以验证壳层隔绝纳米粒子增强拉曼光谱技术。实验结果表明,该测试系统具有较高的测试灵敏度和较短的测试时间,广泛地适用于食品安全中痕量物质快速检测。     

EPON网络承载“我的e家”方案研究

本文深人分析了EPON网络的建设模式,研究了"我的e家"业务对宽带接入网的要求以及"我的e家"业务在EPON网络各种组网模式中的承载方案,并对EPON设备提出了新的技术要求.以实质性地推动中国电信"光进铜退"的发展.     

Organic perovskites

The past 20 years have witnessed the rapid growth of photonic integration circuits(PIC)technology,which has been warmly embraced by both academia and the industry.Powered by the advanced development in material growth,processing,and design capability,the PIC technology now covers multiple material platforms,including III–V(InP,GaAs),silicon,silica,lithium niobate on insulator(LNOI)polymer,etc.The integration level has evolved from a single functional device to thousands of components on-chip.The increase in the performance and the complexity of the PICs have become an energetic booster for communication and information technology.     

EPON还是GPON:FTTH的技术选择

EPON和GPON均为实现FTTH的重要技术,但在FTTH网络建设时应选择其中哪一种业界一直争论不休.本文从FTTH产业链各环节多角度出发,提出运营商主宰FTTH技术选择的观点,并建议运营商在技术选择时应考虑技术、产业链发展、成本以及时间等多个维度.     

Current mismatch due to local dopant fluctuations in MOSFET channel

A microscopic multitransistor model is developed to analyze the impact of local dopant fluctuation on the intrinsic mismatch of long-channel MOSFET. A closed analytical formula for current mismatch is derived to show a nonscaled and self-consistent form /spl sim/[4+Log(L/L/sub min/)]/WL. This is in contrast to the global fluctuation model, in which the current mismatch has a universal scaling form /spl sim/1/WL but is not self-consistent if a MOSFET is modeled as an equivalent two-transistor system. The weak violation of scaling law results from the local fluctuation that has more impact on longer channel devices than on shorter ones. Our new model is consistent with recent experimental observation and can explain the discrepancies between the experimental data and the existing models. The analysis indicates that the local dopant fluctuation is the major cause and accounts for about 60% to 80% of total current mismatch when operated at lower gate voltage, a usual regime for higher output impedance.     

航天级双读数多圈绝对式光电编码器设计

利用多圈光电编码器具有体积小、量程大以及数字量输出等优点,设计了基于双读数系统的航天级多圈绝对式光电编码器。根据航天相机的精度要求,采用精度高、分辨率高的绝对式矩阵玻璃码盘作为一级码盘完成角度测量;根据电机转动的计数要求,采用重量轻,体积小的绝对式矩阵金属码盘作为二级码盘完成对一级码盘的转动圈数计数;其具有的双狭缝及双读数系统可实现信号处理电路冷备份。按照鉴定级航天产品要求,通过热学环境实验和力学环境实验对编码器性能进行了验证。实验结果表明,所设计的编码器精度范围为±100″内、分辨率为80″、测量圈数为16圈、外形尺寸为φ50 mm×50 mm、重量为270 g,稳定性高、可靠性强,且满足高分辨率航天设备设计指标。     

大功率激光光束光斑诊断仪及其测试原理

针对激光加工用大功率激光的特点,分析了国内外现有的几种大功率激光光束诊断系统的测试原理和性能.详细介绍了一种能对大功率激光光束光斑在线测量的诊断仪.     

High-Performing Quasi-2D Perovskite Photodetectors with Efficient Charge Transport Network Built from Vertically Orientated and Evenly Distributed 3D-Like Phases

Quasi-two-dimensional (Q-2D) perovskites are emerging as one of the most promising materials for photodetectors. However, a significant challenge to Q-2D perovskites for photodetection is their insufficient charge transport ability, which is mainly attributed to their hybrid low-dimensional n-phase structure. This study demonstrates that evenly-distributed 3D-like phases with vertical orientation throughout the film can greatly facilitate charge transport and suppress charge recombination, outperforming the prevalent phase structure with a vertical dimension gradient. Based on such a phase structure, a Q-2D Ruddlesden−Popper perovskite self-powered photodetector achieving a combination of exceptional figures-of-merit is realized, including a responsivity of 0.45 AW⁻¹, a peak specific detectivity of 2.3 × 10¹³ Jones, a 156 dB linear dynamic range, and a rise/fall time of 2.89 µs/1.93 µs. The desired phase structure is obtained by utilizing a double-hole transport layer (HTL), combining hydrophobic PTAA and hydrophilic PEDOT: PSS. Besides, the dependence of the hybrid low-dimensional phase structure is also identified on the surface energy of the buried HTL substrate. This study gives insight into the correlation between Q-2D perovskites’ phase structure and performance, providing a valuable design guide for Q-2D perovskite-based photodetectors.