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GOCE卫星重力梯度观测值为高阶静态重力场反演提供了重要的数据支撑，但其在使用前需考虑扣除时变重力场变化的影响。本文研究了GOCE卫星重力梯度观测值的时变重力场变化改正方法，更新了ESA标准和背景模型，以更好地扣除时变重力场变化的影响，自主实现了由GOCE卫星Level 1b重力梯度数据直接进行重力场反演。本文通过3种时变重力场变化改正方案分析了其对高阶静态重力场反演的影响，研究结果表明：从全球大地水准面差异看，时变重力场变化改正对重力场反演是有影响的，其在局部区域对大地水准面的影响值最大可超过1 cm，说明利用GOCE卫星重力梯度数据反演高阶静态重力场时需扣除时变重力场变化改正，同时新标准和背景模型更有利于扣除时变重力场变化的影响。

China＇s economy enjoys the prominent characteristics of a dual structure, with a severe surplus in the agricultural labor force. Scholars in China and overseas have conducted extensive research on the issue of labor surplus and have developed estimates on the size and percentage of surplus labor. The results, however, vary considerably due to the differences in methods and data sources. Based on existing research and using the National Agricultural Costs and Returns Compilation as the data source, this paper proposes that the size of the agricultural surplus labor force is only 8,520,000 persons, accounting for 2.1% of the total rural labor force.

Multi-walled carbon nanotubes（MWCNTs） reinforced hollow glass microspheres（HGMs）/epoxy syntactic foam was fabricated. The effects of ultrasonication on the density, compression strength, and water absorption properties were studied. Better dispersed MWCNTs can be obtained after ultrasonication treatment, but an increasing viscosity will lead to a larger amount of voids during syntactic foam preparation especially when the content of HGMs is more than 70 vol%. The existing voids will decrease the density of epoxy syntactic foam. However, the ultrasonication does not change the compression strength much. Ultrasonication treatment will decrease the water absorption content due to the better dispersion and hydrophobic properties of MWCNTs. But a significant increase of water absorption content occurs when HGMs is more than 70 vol%, which is attributed to the higher viscosity and larger amount of voids.

TP393; 联邦学习以参与设备之间协作训练全局模型的形式,有效地解决了数据隐私等问题.然而,在复杂的网络环境中,网络拓扑和设备算力等因素极其影响联邦学习的训练和通信过程.作为一种算力可测、可感知、可分配、可调度和可管理的新型网络架构和范式,6G中的算力网络恰好能有效支持联邦学习训练并提高其通信效率.根据业务需求、资源负载、网络条件和设备算力等信息,算力网络可以决策联邦学习的训练进而实现通信效率提高.为了提高复杂网络环境下联邦学习的通信效率,本文研究了其在6G算力网络中的通信效率优化方法,针对不同的网络条件和参与设备的算力作出训练过程的决策.仿真实验基于联邦学习中存在的两种架构,依据算力信息调度设备参与训练,并在传输模型参数的过程中实现通信效率的优化.仿真结果表明,本文提出的方法能够很好地应对复杂的网络情况,有效平衡参与设备的本地训练延迟差异,提高在传输模型参数时的通信效率,并提高网络中的资源利用率.

A large number of experimental and theoretical investigations of carbon dioxide （CO 2 ） spectra have been conducted since the most recent update of the High-Resolution Transmission Molecular Absorption （HITRAN） database. To maintain optimal parameters, the HITRAN 2004 CO 2 line list has been completely replaced by HITRAN 2008 data in the near-infrared region from 4300 cm-1 to 7000 cm-1 . To examine the effect of this change on the retrieval of CO 2 vertical column data from reflected sunlight spectra in the 1.61-μm spectral window, synthetic measurements for a given atmospheric state and instrument setup were generated and compared using radiative transfer model with the line-transition parameters from the HITRAN 2004 and 2008 databases. Simulated retrievals were then performed based on the optimal estimation retrieval theory. The results show that large systematic errors in atmospheric CO 2 column retrievals were induced by the differences in the HITRAN laboratory line parameters in the 1.61-μm region. The retrieved CO 2 columns were underestimated by 10 ppm using the HITRAN 2004 data, and improvements resulting from the use of the improved HITRAN database were more pronounced at a higher spectral resolution.