Stacking of two-dimensional (2D) van der Waals (vdW) atomic sheets has been established as a powerful approach to fabricating new materials with broad versatilities and emergent functionalities. Here we demonstrate a bottom-up approach to fabricating isolated single W 6 Te 6 wires and their lateral assemblies, offering a unique platform for investigating the elegant role of vdW coupling in 1D systems with atomic precision. We find experimentally and theoretically a single W 6 Te 6 wire is a 1D semiconductor with a band gap of ∼60 meV, and a semiconductor-to-metal transition takes place upon interwire vdW stacking. The metallic multiwires exhibit strong Tomonaga−Luttinger liquid characteristics with the correlation parameter g varying from g = 0.086 for biwire to g = 0.136 for six-wire assemblies, all much reduced from the Fermi liquid regime (g = 1). The present study demonstrates wire-by-wire vdW stacking is a versatile means for fabrication of 1D systems with tunable electronic properties.

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The operation of large-scale reservoirs have modified water and sediment transport processes, resulting in adjustments to the river topography and water levels. The polynomial fitting method was applied to analyze the variation characteristics of water levels under different water discharge values in the Jingjiang reach of the Yangtze River from 1991-2016. The segregation variable method was used to estimate the contributions of the varied riverbed evaluation, the downstream-controlled water level, and the comprehensive roughness on the altered water level at an identical flow. We find that low water levels in the Jingjiang reach of the Yangtze River from 1991-2016 are characterized by a significant downward trend, which has intensified since 2009. Riverbed scouring has been the dominate factor causing the reduced low water level while increased roughness alleviated this reduction. From 1991-2016, there was first a decrease followed by an increase in the high water level. The variation characteristic in terms of the "high flood discharge at a high water level" before 2003 transformed into a "middle flood discharge at a high water level" since 2009. The increased comprehensive roughness was the main reason for the increased high water level, where river scouring alleviated this rise. For navigation conditions and flood control, intensified riverbed scouring of the sandy reaches downstream from dams enhanced the effects that the downstream water level has on the upstream water level. This has led to an insufficient water depth in the reaches below the dams, which should receive immediate attention. The altered Keywords: water level at identical flow; spatio-temporal evolution; channel geomorphology; middle reaches of the Yangtze River

Sediment accumulation has been the most important factor influencing the comprehensive benefit of reservoirs. A quantitative investigation of the sediment trapping efficiencies of reservoirs is a key to understanding the impact of sedimentation on reservoirs. Generally, the simplest method to assess sediment accumulation ratio is adopting sediment concentration curve with trap efficiency (TE) of the reservoir. Many empirical and semi-empirical models have been proposed to determine this term related to the average annual inflow, features and characteristics of the reservoir watershed area. In this article four different empirical models decided by capacity to inflow ratio (C/I), capacity to watershed ratio (C/W) were used. These different models were summarized and utilized to determine TE of large reservoirs on the Upper Yangtze River for recent decades. Based on these conventional models, an improved model to estimate sediment trapping efficiency is proposed, and experimental data from other 18 reservoirs come from different basins were used to validate the model. The results indicate that the sediment trapping efficiencies that were estimated by the four empirical model were similar to the measured efficiencies for reservoirs on the Upper Yangtze River. Among the the Brune and Siyam empirical models were the most reliable and can be applied to estimate sediment trapping efficiency for reservoirs on the Upper Yangtze River. The improved model takes the capacity/annual inflow ratio and capacity/watershed area ratio into account comprehensively, the effect of particle size and settling velocity of the sediment are also considered, it is more applicable and accuracy to predict large reservoir sediment trapping efficiency. The results of this study provide a valuable reference for predicting large reservoir sedimentation and sediment regulation.