搜索结果: 1-15 共查到“工学 KM”相关记录112条 . 查询时间(0.078 秒)
中国移动联合团队成功研制突破0.1dB/km的超低损空芯光纤
中国移动 超低损 空芯光纤 光纤通信
2024/9/23
近日，中国移动研究院、领纤科技、暨南大学联合团队提出新型反谐振空芯光纤方案并完成制备，采用四单元截断型双层嵌套结构设计，实现了低于0.1dB/km的超低传输损耗和2.6万倍的高阶模式抑制比纪录，在国内首次突破0.14dB/km实芯光纤理论损耗极限，达到国际领先水平。相关成果近期发表在国际学术会议OPTICA Advanced Photonics Congress，是反谐振空芯光纤技术和产业发展的标...
月球岩浆洋模型认为岩浆洋晚期会在月幔顶部形成富含钛铁矿的辉石岩堆晶（IBC）以及富集放射性元素的克里普组分（KREEP）。而IBC堆晶由于密度较大会沉入深部引发月幔翻转。一些研究认为是下沉到深部的IBC的活动导致了嫦娥五号玄武岩（CE5）的形成。然而，这一观点会面临两个问题：1）IBC的沉降发生在岩浆洋结晶的晚期（~44-43亿年）；2）之前的研究认为CE5玄武岩是由低钛玄武岩演化而来，而后者源区...
60~100 km低电离层对无线电传播、测量具有重大影响。IRI2016作为目前最新的国际参考电离层模型，研究其提供的电子密度在高度60~100 km的精度具有重要实际意义。本文以廊坊中频雷达（位于中纬度地区）提供的电子密度资料（2014—2016年）为基准，利用偏差、绝对差、相关系数、相对偏差和Lomb-Scargle周期图方法，定量分析了IRI2016模型电子密度在中纬度地区60~100 km...
Development & assessment of the global land one-km base elevation Digital Elevation Model (GLOBE)
Environmental variables Global Database Topography
2016/5/20
The Global Land One-kilometer Base Elevation (GLOBE) digital elevation model is the most thoroughly designed, reviewed, and documented global digital elevation dataset to date. GLOBE was developed by ...
9.2 GHz频率信号50 km光纤传递
微波频率 光纤 相位共轭 频率传递
2016/12/6
基于相位共轭稳相方法研制微波频率传递系统,简化传递系统光路,实现光纤微波频率传递链路噪声的实时补偿,完成50 km光纤9.2 GHz超稳微波频率传递实验.该系统采用模块化设计,由微波参考信号生成模块、相位补偿模块、光纤传递模块组成.在实验室环境下经过9 d的连续测试,结果表明,自由运转时频率传递的稳定度(标准阿伦方差)为4.2E-13@1 s,4.3E-14@1 d;补偿后频率传递系统的稳定度达到...
UTILIZING THE GLOBAL LAND COVER 2000 REFERENCE DATASET FOR A COMPARATIVE ACCURACY ASSESSMENT OF GLOBAL 1 KM LAND COVER MAPS
global land cover accuracy assessment
2015/5/6
Many investigators use global land cover (GLC) maps for different purposes, such as an input for global climate models. The current GLC maps used for such purposes are based on different remote sens...
406.6-Gb/s PDM-BPSK Superchannel Transmission over 12,800-km TWRS Fiber via Nonlinear Noise Squeezing
406.6-Gb/s PDM-BPSK Superchannel Transmission 12,800-km TWRS Fiber Nonlinear Noise Squeezing
2014/11/6
We transmit a 406.6-Gb/s superchannel consisting of eight 37.5-GHz-spaced 32-Gbaud Nyquist-filtered PDM-BPSK signals over 12,800-km (160×80-km) EDFA-only amplified dispersion-unmanaged TWRS fiber. Thi...
High Capacity Field Trials of 40.5 Tb/s for LH Distance of 1,822 km and 54.2 Tb/s for Regional Distance of 634 km
High Capacity Field Trials 40.5 Tbs for LH Distance of 1,822 km 54.2 Tbs for Regional Distance 634 km
2014/11/6
40.5 Tb/s over 1,822km and 54.2 Tb/s over 634km field SSMF was realized using 41 Nyquist rate DP-8QAM and DP-16QAM superchannels. They are the highest field capacities for long-haul and regional dista...
Single-carrier 400G interface and 10-channel WDM transmission over 4,800 km using all-ETDM 107-Gbaud PDM-QPSK
Single-carrier 400G interface 10-channel WDM transmission over 4,800 km all-ETDM 107-Gbaud PDM-QPSK
2014/11/6
We transmit all-electronically multiplexed 107-Gbaud polarization-multiplexed quadrature-phase-shift-keying over 4,800-km using coherent detection based on a real-time oscilloscope with 63-GHz electro...
146λ××6××19-Gbaud Wavelength- and Mode-Division Multiplexed Transmission over 10××50-km Spans of FewMode Fiber with a Gain-Equalized Few-Mode EDFA
146λ××6××19-Gbaud Wavelength Mode-Division Multiplexed Transmission over 10××50-km Few Mode Fiber Gain-Equalized Few-Mode EDFA
2014/11/6
We demonstrate wavelength- and mode-division multiplexed transmission over a fiber re-circulating loop comprising 50-km of low-DMGD few-mode fiber, and an optimized few-mode EDFA with a flat gain spec...
32-bit/s/Hz Spectral Efficiency WDM Transmission over 177-km Few-Mode Fiber
32-bit/s/Hz Spectral Efficiency WDM Transmission over 177-km Few-Mode Fiber
2014/11/6
We transmit 32 WDM channels over 12 spatial and polarization modes of 177 km few-mode fiber at a record spectral efficiency of 32 bit/s/Hz. The transmitted signals are strongly coupled and recovered u...
基于1 km网格的天津市二氧化碳排放研究
城市CO2排放 1 km网 空间特征
2013/11/11
中国城市建制及地理边界特征使得国际城市CO2排放的关键问题在中国难以深入研究.例如,城市排放占比,城市与周边区域排放差异等.本文基于天津市CO2排放的1 km网格,分析天津市CO2排放的空间特征,探讨天津市不同城市范围的CO2排放水平,并与纽约市进行对比分析.结果显示,2007年天津市市域内CO2排放总量为12599万吨,人均排放11.30 t.天津市市域CO2排放的空间格局是从中心6个城区向外单...
100 km量子纠缠分发实验捕获跟踪技术
量子通信 量子纠缠分发 捕获跟踪瞄准
2014/3/11
介绍了100 km量子纠缠分发实验中的捕获跟踪瞄准（ATP）技术。以Alice接收端的700 mm望远镜为例分析了ATP系统的技术指标、光路布局和高带宽跟踪精度的实现方法。为了抑制近地面水平大气湍流引起的量子信息传输光束和信标光束的到达角起伏， 在经典复合轴跟踪模式的基础上，设计了具有粗跟踪、精跟踪和超精跟踪功能的双重复合轴跟踪系统和双快速控制反射镜融合的跟踪算法，用高帧频CMOS探测器和压电快速...
This letter proposes and experimentally demonstrates a cost-effective phase-modulation duobinary modulation scheme for improving self-phase modulation tolerance using a single modulator. Successful tr...
A novel bidirectional transmission system is proposed and experimentally demonstrated using a four-port interleaver to enable unidirectional amplification. Following bidirectional transmission through...