China Nonferrous Metals Changsha Investigation Design Institute

Introduction Microbially induced desaturation and precipitation (MIDP) is a promising environmentally friendly technique for improving liquefiable coastal sands; however, the key factors governing microbial gas-production efficiency and their governing patterns remain insufficiently understood. Methods To clarify the gas-production characteristics of Pseudomonas stutzeri for potential MIDP application in coastal liquefied sand treatment, this study systematically investigated the effects of temperature, pH, bacterial concentration (OD 600 ), and nitrate concentration (KNO 3 ) using a four-factor, five-level orthogonal experimental design under controlled laboratory conditions. Results The results show that gas-production efficiency increases markedly with temperature from 10 to 30 °C. Increasing pH from 5 to 9 enhanced the gas-production rate by 2.3-fold. As OD 600 increased from 0.05 to 0.25, gas production first improved and then declined, with the optimum performance observed at OD 600 = 0.10. Among the investigated factors, KNO 3 concentration was identified as the most influential variable controlling gas production by Pseudomonas stutzeri . Discussion These findings provide an experimental basis for optimizing the application of MIDP in the anti-liquefaction treatment of coastal liquefiable sand.

Two-dimensional (2D) covalent polymers offer environmental stability, surface area, and mechanical resilience, but preparation of functional, freestanding 2D polymers remains challenging. Inspired by phospholipid bilayers, we developed a bilayer self-assembly strategy for 2D covalent polymer synthesis with tailored functionalized surface. Ionic amphiphilic styrene monomers employ intramolecular face-to-face stacking, inducing a folded monomer conformation that achieves a critical packing parameter near unity. This drives 2D nanosheet formation in basic aqueous solution. Concurrent electrostatic repulsion enabled spontaneous exfoliation. In situ radical polymerization within preorganized framework, accelerated by nanoconfinement effect, converted supramolecular assemblies into covalent bilayer polymers with 95% monomer conversion. Incorporating sulfonic acid-functionalized 2D polymers (0.66wt%) into Nafion D2020 membrane enhanced mechanical strength and proton conductivity at room temperature. Fuel cell testing (70°C, 100% RH) demonstrated increased open-circuit voltage (1.00V vs. 0.96V), suppressed hydrogen permeation, elevated peak power density (678.9vs. 454.6 mW·cm-2), and reduced ohmic resistance (25.2vs. 55.1mΩ).

Abstract Epithermal deposits are characterized by complex low‐temperature hydrothermal alterations, but the links between mineralization and superimposed alteration are obscure and require further elucidation. This study employs short‐wave infrared (SWIR) spectral scalars for alteration mineral mapping and three‐dimensional modeling of the Ulan Uzhur Ag polymetallic deposit, a newly discovered epithermal deposit in the Qimantagh. Alteration zoning transitions from illite‐muscovite‐carbonate‐pyrite in the core (Zone I), through muscovite ± illite‐kaolinite‐chlorite‐carbonate (Zone II), to muscovite‐chlorite‐biotite (Zone III) at the periphery. The Zone I with mineralization features long‐wavelength white mica (wAlOH > 2207 nm) with a high Illite Crystallinity (IC) (mean > 2.0), suggesting a relatively high‐temperature environment conducive to mineralization. Petrographic analyses with fluid inclusion and IC curve characteristics suggests that fluid boiling may be a pivotal mechanism for mineral precipitation. Furthermore, surface mapping and deep three‐dimensional modeling of spectral characteristics reveal a correlation between long‐wavelength white mica, high IC and mineralization zones. These findings indicate that SWIR spectroscopy reveal the evolution of fluids and provide valuable guidance for future exploration efforts.

The nuclear magnetic resonance (NMR) T₂ distributions of free fluid are widely used to characterize the bulk relaxation properties of fluids. However, in the heavy crude oil of reservoirs in the western South China Sea, solid-phase impurities such as waxes, asphaltenes, and colloids result in multi-peak, broad-spectrum T₂ distributions. This complexity hinders accurate peak identification and fluid property analysis. To address this, typical crude oils from the study area were selected, and their free-fluid T₂ distributions were measured under reservoir-temperature conditions. The observed multi-peak patterns were analyzed to determine their physical and chemical origins. Based on the Gaussian distribution function, a fast Gaussian picking method is proposed to search for representative distribution peaks in crude oil in conjunction with extreme points. The non-negative least squares (NNLS) method is utilized to fit the data, and the complex T₂ distribution was decomposed into components representing different phases and viscosities. After mathematical-physical tests and demonstrations, the rapid classification of the T2 distribution of the free-fluid state of impurity-containing viscous crude oil is realized. Applied to downhole NMR data, the method accurately captured the T₂ characteristics of such crude oils, offering a fast and reliable tool for analyzing complex bulk relaxation behaviors and fluid identification. Finally, the method’s performance, influencing factors, and applicability were discussed.