Soil Stratum Tides

River deltas, where ocean tides can often freely propagate into the river, are focal points of human settlement. Beneath the delta surface, groundwater stored in the soil strata fluctuates with river tides, resulting in pressure variations within the soil strata. Here, we introduce a novel ultra-weak fiber-optic instrument to test the hypothesis that tide-induced groundwater level variations induce periodic soil stratum deformation. Using borehole deployments ranging over 70 m in the subsurface of the Yangtze Delta, we observe semidiurnal and spring–neap cycles of soil stratum deformation and reveal its dependence on lithology and depth. This allows us to coin the new term “soil stratum tide,” defined as the periodic deformation of soil strata in response to pressure fluctuations induced by tides in open water. High-accuracy monitoring of the breathing of tidal deltas enables calibrating Earth observation systems, analysis of delta subsidence, and safeguarding of infrastructure jeopardized by soil stratum deformation

Data supporting "Soil stratum tides"

This archive contains data that support the conclusions of the manuscript "Soil stratum tides"

Ultra-weak FBG sensing for identification and analysis of plastic zone of soil caused by supported excavation

Deformation caused by supported excavation makes significant impact on foundation pit stability. Evaluation of potential plastic zone is crucial for early warning of foundation pit instability. To address the shortcomings of existing evaluation methods, a new identification method based on the ultra-weak fiber Bragg grating (UWFBG) technology was proposed. To validate this approach, a UWFBG monitoring program was implemented in the boreholes as part of the Shanghai Metro Line 18 project. The monitoring results were utilized to determine the range of plastic zone for each borehole. It was noted that there are two plastic deformation zones formed with different mechanisms, one located near the base of the diaphragm wall (DW) and the other is distributed within the range of 6–19 m below the excavation face. Lastly, a criterion of early warning of foundation pit instability was presented. By analyzing the monitoring data, the highest risk level of this project was determined as “Attention”, implying the necessity of taking measures to prevent the local plastic zone from evolving into a full-scale sliding surface.The authors gratefully acknowledge the financial supports provided by the National Natural Science Foundation of China (Grant 42030701) and the China Scholarship Council (Grant number 202106190132)

Holey Graphitic Carbon Derived from Covalent Organic Polymers Impregnated with Nonprecious Metals for CO2 Capture from Natural Gas

Natural gas (NG), as a renewable and clean energy gas, is considered to be one of the most attractive energy carriers owing to its high calorific value, low price, and less pollution. Efficiently capturing CO2 from NG is a very important issue since CO2 reduces energy density of natural gas and corrodes equipment in the presence of water. In this study, the authors use holey graphene-like carbon derived from covalent organic polymers (COP) impregnated with nonprecious metals, i.e., COP graphene, as highly efficient separation materials. The dual-site LangmuirFreundlich adsorption model based ideal absorbed solution theory is applied to explore the adsorption selectivity. The experimental results along with first principles calculations show Mn-impregnated COP graphene exhibits greater CO2/CH4 selectivity than Fe and Co impregnated materials. Particularly, the selectivity of CCOPPMn reaches 11.4 at 298 K and 12 bars, which are much higher than those in many reported conventional porous materials and can be compared to the highest separation performance under similar condition. Importantly, all the three COP graphene show remarkably high regenerability (R &gt; 77%), which are much better than many reported promising zeolites, active carbon, and metal organic frameworks. Accordingly, COP graphene are promising cyclic adsorbents with high selectivity for separation and purification of CO2 from natural gas.</p

Cortical activation and brain network efficiency during dual tasks: An fNIRS study

Objective: Dual task (DT) is a commonly used paradigm indicative of executive functions. Brain activities during DT walking is usually measured by portable functional near infrared spectroscopy (fNIRS). Previous studies focused on cortical activation in prefrontal cortex and overlooked other brain regions such as sensorimotor cortices. This study is aimed at investigating the modulations of cortical activation and brain network efficiency in multiple brain regions from single to dual tasks with different complexities and their relationships with DT performance. Methods: Forty-two healthy adults [12 males; mean age: 27.7 (SD=6.5) years] participated in this study. Participants performed behavioral tasks with portable fNIRS simultaneous recording. There were three parts of behavioral tasks: cognitive tasks while standing (serial subtraction of 3′s and 7′s), walking alone and DT (walk while subtraction, including serial subtraction of 3′s and 7′s). Cognitive cost, walking cost and cost sum (i.e., sum of cognitive and walking costs) were calculated for DT. Cortical activation, local and global network efficiency were calculated for each task. Results: The cognitive cost was greater and the walking cost was less during DT with subtraction 3′s compared with 7′s (P’s = 0.032 and 0.019, respectively). Cortical activation and network efficiency were differentially modulated among single and dual tasks (P's < 0.05). Prefrontal activation during DT was positively correlated with DT costs, while network efficiency was negatively correlated with DT costs (P's < 0.05). Conclusions: Our results revealed prefrontal over-activation and reduced network efficiency in individuals with poor DT performance. Our findings suggest that reduced network efficiency could be a possible mechanism contributing to poor DT performance, which is accompanied by compensatory prefrontal over-activation

Simulations of the breakdown characteristics of n-on-p backside-illumination Silicon Photomultipliers by TCAD

This paper investigates, using Synopsys Sentaurus TCAD simulation, the dependence of the breakdown voltage of n-on-p backside-illumination Silicon Photomultipliers (BSI-SiPM) on the implantation dose, the implantation energy and the screening SiO2 thickness for implantation in p-enrichment region. The simulation results indicate that the breakdown voltage decreases linearly with the implantation dose and a high implantation energy can minimize the impact of the screening SiO2 thickness on the breakdown voltage. Additionally, some key process parameters implemented in coming fabrication have been obtained. Keywords: Silicon photomultiplier, Backside-illumination, Breakdown voltage, TCAD simulatio

Risk factors and a prediction model for sepsis: A multicenter retrospective study in China

Background: Sepsis is typically associated with poor outcomes. There are various risk factors and predictive models for sepsis based on clinical indicators. However, these models are usually predictive of all critical patients. This study explored the risk factors for 28-day outcomes of patients with sepsis and developed a prognosis prediction model. Methods: This was a multicenter retrospective analysis of sepsis patients hospitalized in three intensive care units (ICUs) from September 1st 2015, to June 30th 2020. Demographic, clinical history, and laboratory test data were extracted from patient records. Investigators explored the risk factors affecting 28-day sepsis prognosis by univariate analysis. The effects of confounding factors were excluded by multivariate logistic regression analysis, and new joint predictive factors were calculated. A model predicting 28-day sepsis prognosis was constructed through data processing analysis. Results: A total of 545 patients with sepsis were included. The 28-day mortality rate was 32.3%. Risk factors including age, D-dimer, albumin, creatinine, and prothrombin time (PT) were predictive of death from sepsis. The goodness-of-fit value for this prediction model was 0.534, and the area under the receiver operating characteristic curve was 0.7207. Further analysis of the immune subgroups (n=140) revealed a significant decrease in CD3+, CD4+CD8-, and CD4+CD29+ memory effector T lymphocytes and an increase in CD56+ natural killer (NK) cells in the hypoalbuminemia group compared with the normal albumin group (65.5 vs. 58.3, P=0.005; 41.2 vs. 32.4, P=0.005; 21.8 vs. 17.1, P=0.029; 12.6 vs. 17.6, P=0.004). Conclusions: Risk factors for 28-day sepsis mortality include age, D-dimer, creatinine, PT, and albumin. A decrease in albumin level may exacerbate immunosuppression in patients with sepsis. This study establishes a prediction model based on these indicators, which shows a good degree of calibration and differentiation. This model may provide good predictive value for clinical sepsis prognosis

Evidence for existence of two different phases in Bi1.8Pb0.2Sr-2Ca2Cu3Ox,

The elaborated and well characterized samples of Bi1.8Pb0.2Sr2Ca2Cu3Ox (2223 phase), as prepared, quenched from a partially melting state, and after melting, were studied carefully by X-ray diffraction (XRD), thermal analysis, electron diffraction (ED), transmission electron microscopy (TEM), and energy dispersive X-ray (EDX) microanalysis. Some evidence for the existence of two different phases in the 2223 phase has been obtained, in which one has incommensurate modulation and the other has none. Our experiment preliminarily gives the conditions for the existence of the two different phases. The phase with incommensurate modulation decomposes before melting, and the phase without it can exist in partially melting state. Based on the above fact, we tried to grow the single crystal of the 2223 phase from a partially melting state and got a small one. Unfortunately, the crystal is very unstable