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Objective There is limited research on the impact of mechanical method connecting passage construction on mainline tunnels and surrounding soil of metro shield interval in water-rich sandy stratum. Method Taking a metro shield tunnel interval project with mechanical method connecting passage construction in water-rich sandy stratum as example, a numerical model is established using ABAQUS finite element software to simulate and analyze the entire process of this engineering. The effects of mechanical method connecting passage construction on mainline tunnels and surrounding soil are investigated. The calculation results are compared with actual engineering monitoring data to verify the reliability of the proposed numerical model. Result & Conclusion Land subsidence along the longitudinal direction of the mainline tunnel and connecting passage caused by mechanical method connecting passage construction exhibits a U-shaped curve, with a maximum land subsidence value of 4.60 mm. The effects of the construction on mainline tunnel deformation are mainly vertical deformation and horizontal deformation along the mainline tunnel. The maximum vertical deformation of the mainline tunnel is 1.08 mm, and the maximum horizontal deformation is 1.28 mm. During construction, the maximum stress in the mainline tunnel suddenly increases with the breakthrough of the connecting passage portal, reaching 52.54 MPa upon completion of the construction. Actual monitoring data show that the fitted land subsidence monitoring data aligns with the trend of numerical calculation results, validating the reliability of the numerical calculations.

The disconnector fault in gas insulated switchgear (GIS) is commonly caused by the combined effects of mechanical, thermal, and electrical factors. Throughout the progression from defect development to a severe fault, various signals, including abnormal vibration, temperature changes, and partial discharge, are generated. The simultaneous measurement and analysis of multi-parameter information pertaining to the GIS disconnector are crucial for accurately determining its operating condition. This study focuses on simulating typical defects in a 220 kV GIS disconnector to investigate the evolution patterns of vibration signals, temperature variations, and partial discharge signals under different contact states. The aim is to establish the correlation between these signals and the condition of the GIS disconnector. Additionally, the study proposes a comprehensive evaluation method for GIS disconnector by incorporating the health index theory and an improved analytic hierarchy process. The proposed method is subsequently applied to practical GIS, demonstrating consistency between the identified fault and the analysis results obtained through the multi-parameter comprehensive evaluation approach. Overall, this research introduces a highly feasible new method for the detection of GIS disconnector conditions.

[Objective] The effects of breccias and round gravels on steep cut slope infiltration, runoff, sediment yield, and hydrodynamic characteristics were analyzed in order to provide a theoretical basis for a soil erosion prediction model and soil conservation on a steep cut slope on the Qinghai-Tibet Plateau. [Methods] Based on the shape and material composition of a steep cut slope and on climatic characteristics along the Pai-Mo road, the cut slope runoff and sediment yield process was observed by using indoor simulated rainfall experiments. The experimental conditions were 50° slope, 120 mm/h rainfall intensity, different gravel contents (30%, 40%, 50%), and different gravel roundness (pebble, breccia). [Results] The average infiltration rate for the pebble slope was higher than for the breccia slope. The average runoff rate for the pebble slope was lower than for the breccia slope. The initial runoff time for the pebble slope was significantly later than for the breccia slope. The water flow state and pattern for both slopes were laminar and jet, respectively. Although the runoff shear force and Reynolds number for the pebble slope was slightly smaller than for the breccia slope, the Froude number and the average flow velocity for the pebble slope were larger than for the breccia slope. Therefore, the ability of runoff to carry sediment was greater for the pebble slope. The sediment yield rate for the pebble slope was double the rate observed for the breccia slope, and the total sediment yield for the pebble slope was about 20% higher than for the breccia slope. [Conclusion] Because pebbles do not fit closely together in the soil, they are more likely to cause turbulence under heavy rainfall, causing small annular rills to form centered on the pebbles scattered all over the pebble slope. The rill density and total sediment yield will be greater for a steep cut slope underlain by alluvial deposits than for a steep cut slope underlain by colluvial deposits.

The valve-side bushing of converter transformer bears AC-DC compound voltage, which has strict requirements on the performance and quality of the bushing. Under DC voltage, the accumulation of space charge at the interface of different medium causes the distortion of local electric field, and the existence of metal particles greatly increases the local electric field strength, both of which reduce the insulation performance of the bushing. In this paper, according to the structure of valve-side bushing of converter transformer, the simulation model of valve-side bushing is established by using finite element analysis software. The electric field distribution of the bushing under different types of voltage after adding space charge and the influence of metal particles on the local electric field are analyzed. The results show that the space charge at the dielectric interface is easier to accumulate under DC voltage, and the space charge is able to cause the distortion of the local electric field inside the bushing under AC-DC compound voltage. The degree of local electric field distortion of metal particles under DC voltage is greater than that under AC voltage, and the influence of metal particles on the degree of electric field distortion has little to do with its location in SF6.

Forests cover four billion hectares (31%) of the Earth’s landmass and contain over 75% of all carbon in vegetation. They provide renewable raw materials and natural amenities, protect land and water resources, harbor biological diversity, and mitigate climate change. However, due to less precipitation, the forest coverage rate is only 5.86% in Northwest China. The forests in these arid areas are mainly distributed in alpine areas, which play a key role in runoff regulation and ensure the ecological and economic development of the middle and lower reaches of the inland basins. In the past several decades, China had experienced large-scale deforestation and reforestation. What were the changes of the few forest areas and growing stock in arid Northwest China? Has forest quality been restored? Changes of that had been analyzed in this article. The results showed that the forest area and growing stock decreased greatly from the 1950s to 1970s; the artificial forest area increased clearly; the natural forest area stabilized from the 1980s, growing stock of forest per unit area was still lower than that in the 1950s; and the forest quality had not yet been restored. Results of the analysis of influencing factors showed that the policy-led human activities in different periods were the efficient cause of forest changes in Northwest China. With the development of forestry science, more and more attention has been paid to forest ecological restoration. “Three-North Shelter Forest Program (TNSFP)” in 1978 had made great progress on forest areas by afforestation, and the ecological benefits and economic benefits also increased remarkably owing to the increase in the artificial forest area. In recent years, great progress on forest areas has been made by afforestation, and the forests also contribute significantly to the ecology and economy. However, large-scale afforestation in the Loess Plateau had caused a phenomenon of large investment and little effect on water conservation in some afforestation areas, which showed that afforestation initiated under different polices, which were not always scientifically based, resulted in unintended consequences. Clear ecological principles should be used to ensure best environmental and forest ecology outcomes.

Aiming at the problem of low rate and poor security in general data transmission system, a multi-channel high-speed data security transmission system scheme is proposed. In this scheme, CPU is used as the control center, FPGA and high-speed serial transceiver TLK2711 are used for high-speed data security transmission in four-channel. To test and verify the feasibility of the scheme，the multi-channel high-speed data transmission system hardware platform is built. The experimental results show that the highest transfer rate in this system can up to 4.8 Gb/s.

Altered transcriptional and epigenetic regulation of brain cell types may contribute to cognitive changes with advanced age. Using single-nucleus multi-omic DNA methylation and transcriptome sequencing (snmCT-seq) in frontal cortex from young adult and aged donors, we found widespread age- and sex-related variation in specific neuron types. The proportion of inhibitory SST- and VIP-expressing neurons was reduced in aged donors. Excitatory neurons had more profound age-related changes in their gene expression and DNA methylation than inhibitory cells. Hundreds of genes involved in synaptic activity, including EGR1, were less expressed in aged adults. Genes located in subtelomeric regions increased their expression with age and correlated with reduced telomere length. We further mapped cell-type-specific sex differences in gene expression and X-inactivation escape genes. Multi-omic single-nucleus epigenomes and transcriptomes provide new insight into the effects of age and sex on human neurons.

A repeat expansion in the C9orf72 (C9) gene is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Here we investigate single nucleus transcriptomics (snRNA-seq) and epigenomics (snATAC-seq) in postmortem motor and frontal cortices from C9-ALS, C9-FTD, and control donors. C9-ALS donors present pervasive alterations of gene expression with concordant changes in chromatin accessibility and histone modifications. The greatest alterations occur in upper and deep layer excitatory neurons, as well as in astrocytes. In neurons, the changes imply an increase in proteostasis, metabolism, and protein expression pathways, alongside a decrease in neuronal function. In astrocytes, the alterations suggest activation and structural remodeling. Conversely, C9-FTD donors have fewer high-quality neuronal nuclei in the frontal cortex and numerous gene expression changes in glial cells. These findings highlight a context-dependent molecular disruption in C9-ALS and C9-FTD, indicating unique effects across cell types, brain regions, and diseases.