多路毫米波接收信号相关合成技术

提出了多站小口径接收系统相关合成接收的方法。介绍了相关运算原理,并用于 毫米波多路接收信号的相关合成。针对大型天线不能机动、造价高的不利因素,提出了小型 化、机动化解决方案。采用三路相关合成技术,改善信噪比47 dB,相当于将天线口 径 减小42%。该方法适用于更多路的相关合成,对接收站的设计有一定参考意义 。     

毫米波线性化固态功放的研制

研制了工作于Ka频段的10 W线性化固态功放。采用预失真技 术的线性化单元主要由一个肖特基二极管和一个电容并联构成,具有增益扩展和相位延迟的 特性, 并且其增益和相位特性具有可调性。将其应用于工作频率为30 GHz、输出功率为10 W 的功放,双音激励信号频率间隔为5 MHz,三阶互调（IMD3）可以改善15 dBc。     

反涂层隐身地面金属目标的毫米波辐射探测方法

针对涂层隐身地面金属目标难以探测的现实问题,从辐射探测角度研究了毫米波交 流辐射计用于发动机工作状态下涂层隐身地面金属目标探测的新方法。在对毫米波交流辐射 计系统组成及工作原理论述的基础上,结合不同条件下目标辐射特性的特点,对毫米波辐射 探测技术反涂层隐身地面金属目标的机理和方法进行分析,并给出理论计算结果,然后利用 研制的3 mm频段全功率交流辐射计,在草地背景上进行了一系列模拟探测实验。实验结果与 理论分析相吻合,验证了毫米波辐射探测技术反涂层隐身地面金属目标的可行性和有效性, 从而为反涂层隐身技术提供了一种新思路。     

波浪作用下的海底管道溢油扩散运移规律

为了最大程度减少溢油事故造成的环境污染及经济损失,对海底管道溢油扩散行为的影响因素进行研究.首先,利用流体力学软件建立了波浪条件下的二维有风模型,并进行了验证.其次,通过二维有风模型进行溢油模拟,分析讨论了原油密度、海浪波长、水面风速等因素对溢油扩散的影响.研究结果表明:1)建立的二维有风模型模拟结果比现有文献中模型更...     

Do rival political parties enforce government efficiency? Evidence from Canada 1867–2021

This paper investigates the role of inter-party rivalry in enhancing federal government efficiency in post-Confederation Canada. It tests and finds confirmation in the data for two hypotheses. The first is that the ex post size of the first versus second seat share margin is a useful metric for the ineffectiveness of political parties in policing the incumbent's spending behaviour over its period of tenure. The second is the hypothesis that shirking by the incumbent governing party is decreased by greater expected electoral contestability and expected contestability is related to the effective number of competing parties (ENPSeats) nonmonotonically. In this regard the results suggest that contestability in Canada reaches a maximum when the incumbent faces a value of ENPSeats that is closer to 2.5 than Duverger's 2.     

Urban wireless traffic evolution: The role of new devices and the effect of policy

The emergence of new wireless technologies, such as the Internet of Things, allows digitalizing new and diverse urban activities. Thus, wireless traffic grows in volume and complexity, making prediction, investment planning, and regulation increasingly difficult. This article characterizes urban wireless traffic evolution, supporting operators to drive mobile network evolution and policymakers to increase national and local competitiveness. We propose a holistic method that widens previous research scope, including new devices and the effect of policy from multiple government levels. We provide an analytical formulation that combines existing complementary methods on traffic evolution research and diverse data sources. Results for a centric area of Helsinki during 2020–2030 indicate that daily volumes increase, albeit a surprisingly large part of the traffic continues to be generated by smartphones. Machine traffic gains importance, driven by surveillance video cameras and connected cars. While camera traffic is sensitive to law enforcement policies and data regulation, car traffic is less affected by transport electrification policy. High-priority traffic remains small, even under encouraging autonomous vehicle policies. Based on peak hour results, we suggest that 5G small cells might be needed around 2025, albeit the utilization of novel radio technology and additional mid-band spectrum could delay this need until 2029. We argue that mobile network operators inevitably need to cooperate in constructing a single, shared small cell network to mitigate the high deployment costs of massively deploying small cells. We also provide guidance to local and national policymakers for IoT-enabled competitive gains via the mitigation of five bottlenecks. For example, local monopolies for mmWave connectivity should be facilitated on space-limited urban furniture or risk an eventual capacity crunch, slowing down digitalization.