Robust Transfer of Optical Frequency over 500km Fiber Link with Instability of 10^(−21)

Our primary objective is to mitigate the adverse effects of temperature fluctuations on the optical frequency transmission system by reducing the length of the interferometer.Following optimization,the phase-temperature coefficient of the optical system is reduced to approximately 1.35 fs/K.By applying a sophisticated temperature control to the remained“out-of-loop”optics fiber,the noise floor of the system has been effectively lowered to 10−21 level.Based on this performance-enhanced transfer system,we demonstrate coherent transmission of optical frequency through 500-km spooled fiber link.After being actively compensated,the transfer instability of 4.5×10^(−16) at the averaging time of 1 s and 5.6×10^(−21) at 10000 s is demonstrated.The frequency uncertainty of received light at remote site relative to that of the origin light at local site is achieved to be 1.15×10^(−19).This enhanced system configuration is particularly well suited for future long-distance frequency transmission and comparison of the most advanced optical clock signals.

非线性光学数据库:理论预测助力材料的快速发现

现代激光技术迫切需要能够通过二次谐波产生相干光的非线性光学材料.然而,只有很少一部分非中心对称晶体材料的非线性光学性质被实验或者理论研究,针对高性能非线性光学晶体材料的探索仍非常有限.本工作建立了迄今为止最大的计算非线性光学晶体材料数据库,其中包含2354个非中心对称晶体结构,以及它们的倍频系数和带隙.本文提供了理论数据的计算细节和其与实验数据的对比验证,以及数据库的详细描述.该数据库的重要特点之一是它包含大量通过进化算法搜索发现的新的热力学稳定和亚稳定结构,这为寻找具有更好性能的新型非线性光学材料提供了可能性.

Adjusting the stiffness of a cell-free hydrogel system based on tissue-specific extracellular matrix to optimize adipose tissue regeneration

Background:Large-area soft tissue defects are challenging to reconstruct.Clinical treatment methods are hampered by problems associated with injury to the donor site and the requirement for multiple surgical procedures.Although the advent of decellularized adipose tissue(DAT)offers a new solution to these problems,optimal tissue regeneration efficiency cannot be achieved because the stiffness of DAT cannot be altered in vivo by adjusting its concentration.This study aimed to improve the efficiency of adipose regeneration by physically altering the stiffness of DAT to better repair large-volume soft tissue defects.Methods:In this study,we formed three different cell-free hydrogel systems by physically crosslinking DAT with different concentrations of methyl cellulose(MC;0.05,0.075 and 0.10 g/ml).The stiffness of the cell-free hydrogel system could be regulated by altering the concentration of MC,and all three cell-free hydrogel systems were injectable and moldable.Subsequently,the cell-free hydrogel systems were grafted on the backs of nude mice.Histological,immunofluorescence and gene expression analyses of adipogenesis of the grafts were performed on days 3,7,10,14,21 and 30.Results:The migration of adipose-derived stem cells(ASCs)and vascularization were higher in the 0.10 g/ml group than in the 0.05 and 0.075 g/ml groups on days 7,14 and 30.Notably,on days 7,14 and 30,the adipogenesis of ASCs and adipose regeneration were significantly higher in the 0.075 g/ml group than in the 0.05 g/ml group(p<0.01 or p<0.001)and 0.10 g/ml group(p<0.05 or p<0.001).Conclusion:Adjusting the stiffness of DAT via physical cross-linking with MC can effectively promote adipose regeneration,which is of great significance to the development of methods for the effective repair and reconstruction of large-volume soft tissue defects.

A combination process of mineral carbonation with S02 disposal for simulated flue gas by magnesia-added seawater

The desulfurization by seawater and mineral carbonation have been paid more and more attention.In this study,the feasibility of magnesia and seawater for the integrated disposal of S02 and C02 in the simulated flue gas was investigated.The process was conducted by adding MgO in seawater to reinforce the absorption of S02 and facilitate the mineralization of C02 by calcium ions.The influences of various factors,including digestion time of magnesia,reaction temperature,and salinity were also investigated.The results show that the reaction temperature can effectively improve the carbonation reaction.After combing S02 removal process with mineral carbonation,Ca^2+removal rate has a certain degree of decrease.The best carbonation condition is to use 1.5 times artificial seawater(the concentrations of reagents are 1.5 times of seawater)at 80℃and without digestion of magnesia.The desulfurization rate is close to 100%under any condition investigated,indicating that the seawater has a sufficient desulfurization capacity with adding magnesia.This work has demonstrated that a combination of the absorption of S02 with the absorption and mineralization of C02 is feasible.