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Although atmospheric CO2 concentrations collected by satellites play a crucial role in understanding global greenhouse gases, the sparse geographic distribution greatly affects their widespread application. In this paper, a hybrid CNN and spatiotemporal Kriging (CNN-STK) model is proposed to generate a monthly spatiotemporal continuous XCO2 dataset over China at 0.25° grid-scale from 2015 to 2020, utilizing OCO-2 XCO2 and geographic covariates. The validations against observation samples, CAMS XCO2 and TCCON measurements indicate the CNN-STK model is effective, robust, and reliable with high accuracy (validation set metrics: R2 = 0.936, RMSE = 1.3 ppm, MAE = 0.946 ppm; compared with TCCON: R2 = 0.954, RMSE = 0.898 ppm and MAE = 0.741 ppm). The accuracy of CNN-STK XCO2 exhibits spatial inhomogeneity, with higher accuracy in northern China during spring, autumn, and winter and lower accuracy in northeast China during summer. XCO2 in low-value-clustering areas is notably influenced by biological activities. Moreover, relatively high uncertainties are observed in the Qinghai-Tibet Plateau and Sichuan Basin. This study innovatively integrates deep learning with the geostatistical method, providing a stable and cost-effective approach for other countries and regions to obtain regional scales of atmospheric CO2 concentrations, thereby supporting policy formulation and actions to address climate change. [ABSTRACT FROM AUTHOR]

In the early twentieth century, traditional handicraft was challenged by the latest technology in China. It is reflected by ethnic costumes combining new and old, as in the waistcoat of this study. This waistcoat made at Gyalrong Tibetan area in Sichuan, China, displays unique local features in terms of its brilliant colors and comprehensive craftsmanship. This study employs techniques such as optical microscopy, infrared spectroscopy, scanning electron microscope and high performance liquid chromatography-mass spectrometry to investigate various aspects of this waistcoat, including its fabrics and dyes. The results showed that the waistcoat was primarily made of cotton and silk, with a bamboo paper layer, and that silk as well as twisted gold and silver threads were employed for the embroidery. Various embroidery techniques were applied, with patterns, color combinations, and characteristics being consistent with those of Tibetan and Shu (蜀) embroidery. In terms of dyeing technology, a wide range of colors were achieved through multi-step dyeing processes using natural dye stuffs like pagoda bud, and synthetic dyes like magenta. These findings indicates that modern technologies were well integrated into traditional garment manufacture in the early twentieth century in China. [ABSTRACT FROM AUTHOR]

More than 50 earthquakes occurred in the Luding region, including a 6.8‐magnitude earthquake on September 5, 2022, which induced huge amounts of geological disasters. As the main triggered factors for the geological disasters, the vegetation, precipitation and temperature show regular changes on the time axis. Thus, this paper based on the spatial–temporal evolution of the precipitation, temperature and normalized difference vegetation index (NDVI), focuses on the susceptibility of the Luding area using the weighted information content method (ICM) and analytic hierarchy process (AHP) for the post‐earthquake regional planning and reconstruction. In the Luding area, it was found that there were 18 debris flow gullies, and 470 geological disasters scattered in the debris flow gullies. The NDVI of the study area has been declining in recent years, with only about 12% of the NDVI increasing from 2015 to 2020. From 2011 to 2015, the annual cumulative precipitation has been dropping overall, while the July average temperature has increasing quadratic functions after decreasing trend. Furthermore, the studied area's geological hazards susceptibility was classified into five categories, with extremely low susceptibility accounting for 5.82%, low susceptibility accounting for 13.61%, moderate susceptibility accounting for 38.54%, high susceptibility accounting for 39.96% and extremely high susceptibility accounting for 2.08%. The geological disasters in moderate, high and extremely high susceptibility accounted for approximately 95.08%, and the covered area of geological disasters in moderate, high and extremely high susceptibility accounted for 88.06%. Through the receiver operating characteristic (ROC) curve of the model verification found the AUC = 0.743. The geological hazards susceptibility study results show that the approach is useful for the analysis and prevention of geological disasters. [ABSTRACT FROM AUTHOR]

Siliceous minerals of the Dengying Formation in the Gaoshiti–Moxi area in the central Sichuan Basin exhibit four types of quartz crystals (cryptocrystalline quartz, chalcedony, microcrystalline quartz, and megacrystalline quartz) and three structural types: cryptocrystalline, microcrystalline, and mosaic (laminated mosaic, window-hole interrupted mosaic, and arc-laminated mosaic). Siliceous minerals have a great influence on the storage performance of the reservoirs in the Dengying Formation. According to the petrophysical parameters of the Dengying Formation and porosity intersection diagrams, the siliceous dolomite and the reservoirs have low impedance characteristics, which makes it difficult to distinguish between them and leads to difficulties in the characterization and prediction of the reservoirs. The transverse wave velocity is favorable for reservoir characterization. Currently, the main method used to estimate the transverse wave velocity is petrophysical modeling, which establishes a relationship between the elastic and physical parameters of the reservoir. In this paper, the siliceous minerals in the dolomite in the study area are regarded as solid inclusions, and the calculation method of the rock matrix modulus is improved by using solid replacement. Then, an improved petrophysical model is constructed by combining the KT (Kuster–Toksöz) model, the DEM (Discrete Element Method) model, the Gassmann equation, and the Wood equation. The transverse wave velocity is estimated using the improved model under the constraint of the longitudinal wave velocity. The shapes of the transverse wave velocity curves obtained by the improved model and the deviations from the measured velocities are significantly better than those of the Xu–Payne model and other models. The results show that the improved model can effectively estimate the transverse wave velocity of the reservoir in this area, which provides a basis for future reservoir predictions in this area. [ABSTRACT FROM AUTHOR]

Landslides are common natural disasters that cause serious damage to ecosystems and human societies. To effectively prevent and mitigate these disasters, an accurate assessment of landslide hazards is necessary. However, most traditional landslide hazard assessment methods rely on static assessment factors while ignoring the dynamic changes in landslides, which may lead to false-positive errors in the assessment results. This paper presents a novel landslide hazard assessment method for the Zagunao River basin, China. In this study, an updated landslide inventory was obtained for the Zagunao River basin using data from interferometric synthetic aperture radar (InSAR) and optical images. Based on this inventory, a landslide susceptibility map was developed using a random forest algorithm. Finally, an evaluation matrix was created by combining the results of deformation rates from both ascending and descending data to establish a hazard level that considers surface deformation. The method presented in this study can reflect recent landslide hazards in the region and produce dynamic assessments of regional landslide hazards. It provides a basis for the government to identify and manage high-risk areas. [ABSTRACT FROM AUTHOR]

Hydropower resources have been developed to the cold regions in the west of China recently, wherein the dam will be subjected to high frequency of repeated freeze-thaw action during the construction process in winter, and thus will cause safety and stability problems of these projects. According to the actual construction situations of Lianghekou hydropower station located in Sichuan Province, one-side freezing and two-side thawing tests of unsaturated core-wall soil samples in a closed system are carried out, and the evolution of temperature, water and displacement as well as their interaction are tested and analyzed. The results show that with the increasing of freeze-thaw cycles, water migration results in a decrease of water content in the unfrozen zone and an increase in the frozen zone, and the water concentration area is formed in the soil column. Simultaneously, a deeper freezing depth accompanied with a shorter thawing duration after 10 freeze-thaw cycles is observed through the temperature field results, whereas a steady fluctuation of the deformation field is showed after the 7th freeze-thaw cycle. Moreover, based on the test results and exiting researches, a thermo-hydro-mechanical coupling model for unsaturated soils subjected to cyclic freeze-thaw action is proposed, in which both the permeability and compressibility are inextricably related to the void ratio, and vary in different calculated areas. Additionally, the effects of number of cycles on initial conditions and model parameters are also considered. Comparisons with the experimental data demonstrate the validity and adaptability of the proposed model in describing the freeze-thaw process of unsaturated soil. Through the combination of experiments and numerical simulation, the freeze-thaw process can be more clearly understood, and related engineering problems can be predicted with the help of the mathematical model in this paper. • One-side freezing and two-side thawing tests of unsaturated soil are carried out. • A thermo-hydro-mechanical coupling model in freeze-thaw process is proposed. • The thermo-hydro-mechanical coupling mechanism is revealed by simulations. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Pianyanzi area in western Sichuan hosts a rare sellaite-bearing orogenic gold deposit. • Gold is mostly present as visible native gold formed in two stages. • Gold precipitation was forced by interaction between auriferous fluids and wall rocks. • Metasomatized mantle lithosphere served a potential source of ore fluids. The Pianyanzi gold deposit is situated at the western margin of the Yangtze Craton, and represents a rare sellaite-bearing orogenic gold deposit. This deposit belongs to the Dauduhe gold belt of southwestern China and remains poorly documented. In this paper we present first petrographic and in-situ geochemistrical and sulfur isotope data from pyrite as well as results of multielement mapping. The deposit is dominated by native gold (average gold fineness = 980.8) filling fractures in minerals (e.g., pyrite, quartz, sellaite and hematite) or also emplaced along the contact interface between mineral grains. Pyrite is the most abundant sulfide mineral of this deposit. We identified five generations of pyrite: Py1, Py2a, Py2b, Py3, and Py4. Gold occurs in sellaite- and hematite-bearing mineral assemblages formed simultaneous with the formation of Py2a&b and Py4, respectively. Py1 formed in the Au-poor ore stage, while Py3 formed during the late galena-dominated sulfide stage. All generations of pyrite exhibit low concentrations of gold with an average value of less than 2 ppm. Py2a&b possess distinctive textures and chemical zonation, with trace elements displaying greater variations compared to Py1, Py3 and Py4. The δ34S values vary from −0.52 ‰ to 7.08 ‰, which is consistent with those of orogenic deposits of the Daduhe gold belt. The deep metasomatized mantle lithosphere acted as a potential source of ore fluids. We conclude that the co-precipitation of native gold and sellaite was triggered by the interaction between auriferous fluids and dolomite. [ABSTRACT FROM AUTHOR]