Results 21 to 30 of about 6,902 (167)
, 2018 利用线性调频(Chirp)信号在水下通信中具有良好的抗噪声和抗多径特性,提出基于Chirp-BOK(binary orthogonal keying,二进制正交键控调制)扩频的水声通信系统。系统采用二进制正交键控调制以及匹配滤波接收器,利用正向调频信号和反向调频信号,结合BOK调制技术,实现适合水声环境的扩频通信系统。噪声信道和多径信道下的仿真实验结果表明,该系统具有良好的抗噪声和抗多径性能,适用于水声系统的扩频通信。国家自然科学基金项目(61701422);;福建省自然科学基金项目 ...
伊锦旺 +4 more
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Jellyfish blooms restructure plankton dynamics and trophic linkages in coastal waters
Functional Ecology, EarlyView.Read the free Plain Language Summary for this article on the Journal blog. Abstract Jellyfish blooms are increasing globally in frequency and intensity, introducing complex ecological interactions, yet the mechanisms by which they alter ecosystem structure remain poorly characterized due to a lack of sustained field observations.
Pengpeng Wang +4 more
wiley +1 more source
Study on Millimeter-Wave Collision Avoidance Radar Based On Digital Beamforming [PDF]
, 2016 近年来，随着交通情况的日益复杂及人们对安全性的要求越来越高，防撞雷达的研究也进入一个快速发展的时期，不断涌现出新的方法和理论。防撞雷达常见的探测方式有超声波、激光等方式。这些方式存在穿透能力较差、作用距离近等缺点，实际工作效果并不是很好。毫米波方式波长短、抗干扰能力强，在雨雪天气下工作良好，且硬件设备具有体积小、重量轻的特点。另外，由于线性调频连续波雷达具有距离分辨率高、结构简单、无距离盲区等优点，因此，基于线性调频连续波方式的毫米波雷达在防撞雷达中得到广泛采用。 目前 ...
庄景波
core
Economic Research on Energy Storage Auxiliary Frequency Regulation of Lithium Iron Phosphate Battery for 2 × 600 MW Coal-fired Unit in Guangdong [PDF]
, 2023 [Introduction] In view of the economic benefits of AGC frequency regulation project of combined energy storage in Guangdong coal-fired power plant, the method of establishing typical engineering cases is demonstrated. [Method] This article summarized the
Binsi LI +4 more
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Distribution, scale, and drivers of mass mortality events in Europe's freshwater bivalves
Conservation Biology, EarlyView.Abstract Mass mortality events (MMEs) are decimating populations and compromising key ecosystem functions around the globe. One taxon particularly vulnerable to MMEs is freshwater bivalve mollusks. This group has important ecosystem engineering capacities and includes highly threatened and highly invasive taxa.
Daniel A. Cossey +39 more
wiley +1 more source
Study on Target Detection Method by Coherent Integration for Frequency Modulation Coded Radar Systems [PDF]
, 2016 在现代战场上，高速低可侦测性目标以及各种电子干扰手段的出现对雷达的目标探测性能提出了更高的要求。调频编码雷达作为一种新型的高距离分辨率雷达，具有数据利用率高、对雷达瞬时带宽要求不高以及抗干扰性能强的优点。为了增强调频编码雷达对微弱目标的检测能力，进一步研究调频编码雷达的相干积累检测方法具有重要意义。因此，本文主要开展了如下创新工作： (1)针对调频编码雷达，提出了一种基于运动补偿的相干积累检测方法。首先对调频编码雷达的回波信号进行建模，利用最大似然估计 ...
王智灵
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The influence of the electrical boundary condition on domain structures and electrocaloric effect of PbTiO3 nanostructures [PDF]
, 2016 本文在基于金兹堡—朗道—德文希尔唯象理论的相场法理论下，应用有限差分方法及四阶龙格—库塔法数值求解，研究不同电学边界条件对铁电纳米点畴结构演化和热电温度效应的影响。本文所用的中间电学边界条件，可以用来表示表面电极与纳米点之间的黏合情况及电极对表面电荷的补偿情况，进而说明退极化电场和退极化电能对系统自由能的影响，不同以往的对退极化能进行权重处理，具有实际的物理意义。 当电学参数λ0为0时，中间电学边界可以退化为开路电学边界条件；当λ0趋向无穷大时，对应于短路电学边界条件，即表面电荷可充分补偿。λ0的值越大，
陈志英
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Research on Energy Storage Planning Method Considering the Dual Constraints of Peak Shaving and Frequency Modulation [PDF]
, 2023 [Introduction] In the process of building a new power system, renewable energy will maintain a high-speed development trend. Along with large-scale grid connection of renewable energy sources such as wind energy and photovoltaic energy, the randomness ...
Lei CHEN, Ting WEN
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Conservation Biology, EarlyView.Abstract Knowledge of species distributions is essential for informing policies on nature conservation and restoration. However, updating them on a regular basis and doing so in a harmonized manner at the international level is difficult. The European Bird Census Council integrated national monitoring data covering 5 years to update farmland bird ...
Sergi Herrando +54 more
wiley +1 more source
Gaoya dianqi, 2023 电池储能系统被认为是解决可再生能源的不确定性和不平衡性导致的功率不足和频率波动的有效途径。基于此，文中提出了一种基于电池的荷电状态SOC(state of charge)的电池储能系统混合控制策略。首先，文中将电池的SOC、调频和调峰需求划分为不同的区域，并对调频和调峰提出相应的控制策略，提出SOC自恢复控制策略。之后提出储能的混合控制策略，基于电池储能的SOC，将储能的调频与调峰功能与SOC自恢复策略相结合，实现储能对电力系统的优化。最后通过仿真分析验证该控制策略的合理性与应对可再生能源波动的能力。
李盈 +9 more
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