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Paper-based electronics have attracted much attention due to their softness, degradability, and low cost. However, paper-based sensors are difficult to apply to high-humidity environments or even underwater. Here, we report a fully paper-integrated piezoresistive sensing system that exhibits flexibility, waterproofing, air permeability, and biocompatibility. This system consists of hydrophobic paper as the substrate and encapsulation layer, conductive paper with a double ‘zig-zag’ and dotted surface structure as the sensing layer, and silver paste films as the interconnects. The structural design of the sensing layer helps to increase the contact area in adjacent layers under pressure and further improves the pressure sensitivity. The piezoresistive system can be worn on human skin in the ambient environment, wet environment, and water for real-time monitoring of physiological signals with air permeability and waterproofing due to its hydrophobic fiber structure. Such a device provides a reliable, economical, and eco-friendly solution to wearable technologies.

Recently, topic modeling has been widely used to discover the abstract topics in the multimedia field. Most of the existing topic models are based on the assumption of three-layer hierarchical Bayesian structure, i.e. each document is modeled as a probability distribution over topics, and each topic is a probability distribution over words. However, the assumption is not optimal. Intuitively, it’s more reasonable to assume that each topic is a probability distribution over concepts, and then each concept is a probability distribution over words, i.e. adding a latent concept layer between topic layer and word layer in traditional three-layer assumption. In this paper, we verify the proposed assumption by incorporating the new assumption in two representative topic models, and obtain two novel topic models. Extensive experiments were conducted among the proposed models and corresponding baselines, and the results show that the proposed models significantly outperform the baselines in terms of case study and perplexity, which means the new assumption is more reasonable than traditional one.

The Lungmachi Formation is widely distributed in Guizhou, Chongqing and the adjacent area. It is important for the study of Silurian biostratigraphy and shale-gas investigation. Based on those biostratigraphically well-studied sections from Guiyang to Huayingshan, we reveal the stage-progressive distribution pattern of the Lungmachi black shales. The distribution of the Lungmachi black shales in the studying area can be subdivided into four geographic belts from the south to the north, reflecting the joint effect of regional and global environmental changes. The graptolite depth zonation model was adopted herein to infer the water depth of major graptolite assemblages from the black shales. The changes in the water depth indicate two major stages. The first stage is named the transgressive distribution stage which ranged from the Persculptograptus persculptus Biozone (LM1, upper Hirnantian) to the Coronograptus cyphus Biozone (LM5, upper Rhuddanian), an interval mostly controlled by global sea-level rise. The second stage, ranging from the Demirastrites triangulatus Biozone (LM6, lower Aeronian) to the Spirograptus guerichi Biozone (LM9, lower Telychian), is named the regressive shrinking stage, during which the black shales were gradually replaced by mixed-facies or carbonate sediments from the south to the north, representing the effects of the persistent uplifting of the Central Guizhou Oldland.

Shoaling is a common type of sedimentation in the evolution of carbonate platform, and commonly has poor continuity. This paper presents a newly discovered and rare type of shoaling, i.e., mega-shoaling in nearly basin scale, which is developed in the Middle Triassic Leikoupo Formation of the Sichuan Basin, southwest China. During the Leikoupo time, the studied Sichuan Basin experienced hot and dry climate conditions and developed a carbonate platform within a restricted epicontinental sea. In B sub-layer of the Lei-1-1 sub-member of the Leikoupo Formation a series of grainstones of shoal facies accumulated throughout almost the entire basin, thereby generating features associated with basin-scale mega-shoaling. By detailed core examination and microscopic observation of thin sections, it is shown that the lithology of this set of grainstones is dominated by doloarenite (calcarenite) followed by oolitic dolomite (limestone). In addition, it contains three types of sedimentary sequences characterized by upward-coarsening and upward-shallowing as the followings: restricted lagoon to platform interior beach; restricted lagoon to platform interior beach and to platform flat; and tidal flat to peritidal beach. Subsequently, a multicyclic stratigraphic division and correlation revealed that this set of grainstones can be well traced and compared horizontally, and is generally isochronous. In addition, a template for logging facies, established based on core calibrations and logging data, was employed to analyze the 235 wells in the basin. The results demonstrate the shoal grainstones to be 10–40 m thick with a 15×104 km2 continuous distribution area. These findings indicate that the carbonate platform developed mega-shoals within a short period of time. The genesis of such a mega-shoaling was investigated by focusing on various shoaling conditions, such as paleo-tectonics, paleo-geomorphology, paleo-climate, sea-level changes, and palaeo-hydrodynamics. A specific combination of independent geological factors creates beneficial geomorphologic conditions for the mega-shoaling including a quiescent paleo-tectonic environment, relatively flat paleo-geomorphology and evaporites filling up and leveling off. In addition, a stably settling carbonate platform underwent sea-level fluctuations through swift transgressions and protracted regressions, which is not only conducive to continuous, multicyclic and superimposed vertical development of grain beaches but also beneficial for the horizontal migration, coalescence and superimposition of individual grain beaches. As a consequence, large-scale and continuously-distributed grain beach sedimentation emerges and mega-shoals develop.