我国大容量通信用高端光纤技术的研究进展

文章总结了我国在高端光纤技术方面的研究进展:400Gbit/s用高端光纤技术包括超低损耗光纤技术和大有效面积光纤技术,我国研制的超低损耗光纤在1 550nm的衰减为0.167dB/km,达到了国际先进水平;但大有效面积光纤在1 550nm的有效面积仅为130μm2,与国际的150μm2有一定差距;在Tbit/s大容量空分复用光纤方面,我国进行了少模光纤、多芯光纤和轨道角动量光纤的基础探索研究,与国际水平相当。研究结论表明,我国在大容量通信用高端光纤技术方面达到了国际先进水平,这为我国下一代高速光纤通信技术探索了新的可能性

Neutron diffraction study of aging process effect on phase structure of single crystal superalloy

The neutron diffraction results obtained by oscillating and fixing during data collection show that the high ageing temperature is effective to eliminate dendrite crystals and the microstrain exists mainly in the ' phase. Based on the microstructure obtained by neutron diffraction and scanning electron microscope, the influence of ageing temperature and time on ' phase are evaluated. The unique misorientations among ' phase grains are observed from superlattice measurements. According to the neutron diffractions of different crystal planes, the crystal symmetry is slightly changed from cubic to quartet (a c) due mainly to the matrix phase and the experimental results also prove the strain deviation in difference orientations, thus providing the basis for the existence of driving force for the raft model. The calculation based on the superlattice diffraction shows that in the interfaces between the and ' phases exists a complex distortion: the mismatch varies from -0.1% to -0.3% and the mismatch value can be reduced by high temperature during the first ageing and long time during the second ageing.</jats:p

巢湖蓝藻水华的季节变化

&lt;正&gt;巢湖是中国第5大淡水湖,位于安徽省中部。100多年前已有记载:到了夏天,巢湖水面上漂浮有&quot;湖靛&quot;,即现在称作的蓝藻水华。历来,湖边农民捞这种湖靛作为肥料。这表明,巢湖蓝藻水华出现在环境污染严重化之前。上世纪90年代后,随着环境污染的日趋严

Determination of the number of ψ(3686) events taken at BESIII

The number of ψ(3686) events collected by the BESIII detector during the 2021 run period is determined to be (2259.3±11.1)×106 by counting inclusive ψ(3686) hadronic events. The uncertainty is systematic and the statistical uncertainty is negligible. Meanwhile, the numbers of ψ(3686) events collected during the 2009 and 2012 run periods are updated to be (107.7±0.6)×106 and (345.4±2.6)×106, respectively. Both numbers are consistent with the previous measurements within one standard deviation. The total number of ψ(3686) events in the three data samples is (2712.4±14.3)×10^