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The Qinling Orogenic Belt (QOB), formed by the subduction and collision between the North China Block (NCB) and the South China Block (SCB), is a key area for exploring the tectonic process and timing of integration between the two blocks. A range of tectonic models have been proposed with regard to the subduction and collision of the QOB, but controversy in the timing and integration process still remain debatable, especially in the late Palaeozoic orogeny. The South Qinling Belt (SQB) is located between the Shangdan and Mianlue sutures, widely dispersed sediments outcropped in the SQB provide natural ground for the detrital zircon study, that could trace the sedimentary provenance and continental crustal evolution history, thus provide important evidence for the late Palaeozoic evolutionary processes in the QOB. In this study, we applied a detailed geochronological U‐Pb zircon dating of the Silurian, Devonian and Permian sedimentary rocks from the SQB. The result of the U‐Pb isotopic data shows distinct age populations at 439–474 Ma of the Silurian samples, ca. 400–490 Ma of the Devonian samples and 260–310 Ma of the Permian samples, respectively. By comparing the regional geochronological data, we sum up that the Silurian detrital zircons are mainly derived from the SQB and the northern margin of SCB (N‐SCB), the Devonian detrital zircon age populations are dominated by the North Qinling Belt (NQB) and SQB and the Permian sediments mainly stemmed from the southern margin of the North China Block (S‐NCB) and the NQB. A mutual age population of the Devonian sediments at ca. 400–490 Ma from the NQB constrains the closure of the Shangdan Ocean between the NCB and the SCB before the middle Devonian times. Ca. 260 ~ 380 Ma age population of the Permian sediments show similarities with the age data from the northern margin of the NCB, indicating an uplift event of NQB before the late Permian, and further constrains the closure of Mianlue ocean later than Permian times. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks with tunable porous crystallinity and outstanding stability have exhibited fascinating pretreatment performance as ideal extraction media. Herein, the β‐ketoenamine‐linked TpPa‐1 synthesized by 1,3,5‐triformylphloroglucinol and paraphenylenediamine was employed as the absorbent for online micro‐solid phase extraction of trace bisphenols combined with high‐performance liquid chromatography detection. A series of characterizations indicated that the TpPa‐1 possessed large surface areas, high stability, and hydrophobicity. The main experimental parameters affecting the extraction efficiency were optimized in detail. Compared with four commercial sorbents, the TpPa‐1 exhibited superior enrichment capacity for extracting bisphenols. Under the optimum conditions, the established method demonstrated a wide linear range and high sensitivity with the limit of detection ranging from 0.05–0.06 μg/L. Furthermore, the developed method was successfully applied to determine bisphenols in plastic samples. Bisphenol A was actually detected in a transparent box with a concentration of 0.31 μg/g, and the recoveries of the four bisphenols in the plastic samples were 80.5–116% with the relative standard deviation less than 9.2%. Such performance was attributed to recognition affinity, including the π‐π affinity, hydrophobic effect, and hydrogen bond. These results demonstrated that TpPa‐1 possessed great potential to be an excellent pretreatment medium for online separation and analysis of trace analytes in complex samples. [ABSTRACT FROM AUTHOR]

Naturally occurring granular uranium particles are typically fine and are often found as accessory minerals. However, reports of megacrystalline uraninite are rare. The discovery of megacrystalline uraninite is a significant achievement in uranium prospecting and mineralogy in the Kangdian region and China. Our team's research and review of previous studies have led to a systematic summary of the formation age, genetic types, relationship with migmatization, and metallogenic dynamic background of megacrystalline uraninite in the Kangdian region. The key findings are as follows: (1) the formation age of megacrystalline uraninite is Neoproterozoic (790–770 Ma); (2) migmatization preceded uranium mineralization; (3) the formation of megacrystalline uraninite is linked to high-temperature, low-pressure metamorphism caused by partial melting; (4) and the formation of megacrystalline uraninite may be associated with the Rodinia rifting event. This review aims to enhance our understanding of uranium mineralization during the Neoproterozoic in China and worldwide. [ABSTRACT FROM AUTHOR]

• The 980 °C/300 MPa creep test results indicate that the creep lives and elongation of the three typical orientations at 980 °C are [1 1 1] orientation > [0 0 1] orientation > [0 1 1] orientation. The necking sections of [0 0 1], [0 1 1] and [1 1 1] orientation are circular and elliptical, respectively. Meanwhile, on the microscopic scale, the damage evolution caused by the expansion of the internal micropores in the single crystal alloy under the three orientations shows fourfold symmetry, double symmetry and triple symmetry. • During the creep process, fracture mechanism is related to the actuation of the slip system and the magnitude of the shear stress on the slip plane. Meanwhile, the damage evolution of nickel-based monocrystalline materials caused by the expansion of micropores is characterized by quadruple symmetry, double symmetry and triple symmetry, which is also attributed to the differences in the moving slip systems and explains the different cleavage planes of different orientations, where the creep life of the [0 1 1] oriented alloy is the shortest compared to the other orientations. • The anisotropic creep constitutive model and damage model based on the crystal plasticity theory can effectively reflect the difference in the creep deformation and damage evolution of a single crystal with different orientations. The simulation results are in agreement with the experimental results, which show that the theory can reflect the anisotropy of the characteristics of single crystal materials. Due to the anisotropy of the modulus of face-centered cubic cells, the nickel-based single crystal alloys exhibits substantial anisotropy at high temperatures. Their creep properties, especially the creep rupture lives, are related to the actuation of the slip system and the magnitude of the shear stress on the slip plane. The creep orientation sensitivity has been analyzed through creep experiments, as well as the microstructure and morphology of the fracture. On the macroscale, the necking sections of [0 0 1], [0 1 1] and [1 1 1] orientations are circular, elliptical and circular, respectively. Meanwhile, on the microscopic scale, the damage evolution caused by the expansion of the internal micropores in the single crystal alloy under the three orientations shows fourfold symmetry, double symmetry and triple symmetry, respectively. Based on the crystal plasticity theory, an anisotropic creep constitutive model and damage model are established to reflect the difference in creep deformation and damage evolution caused by orientation. The numerical simulations of the whole creep process of a second generation nickel-based single crystal superalloy show that the creep constitutive model and damage model can simulate the deformation and damage of the specimen under different orientations, and the creep life can be obtained. [ABSTRACT FROM AUTHOR]

Microstructure evolution occurs throughout the high temperature creep process inside nickel-based single crystal superalloys. In this study, creep tests of a nickel-based single crystal superalloy in the [001] orientation at 980 °C and 1100 °C were performed. The results indicated that creep failure occurred due to the formation of micropores and deterioration. Scanning electron microscopy (SEM) observations showed that the material degradation during creep was primarily reflected in the coarsening of the matrix channel and the precipitation of the TCP phase. Meanwhile, transmission electron microscopy (TEM) observations indicated that the dislocation morphology of the [001] orientation is consistent with the characteristics of the octahedral slip system. To obtain a quantifying explanation of such microscopic phenomena, a material constitutive model and creep damage model considering the Orowan effect and the dislocation effect were established based on the crystal plasticity theory. The model parameters were fitted according to the experimental results. Based on the quantitative description of the microstructure evolution during the creep process, the residual life prediction model of a single crystal superalloy was established for guidance in engineering applications. [ABSTRACT FROM AUTHOR]

A new hydrazone bond covalent organic polymer (BTH-PD-COP) was well designed and successfully synthesized based on the principle of Schiff-base reaction and the concept of reticular chemistry with 1,3,5-Benzenetricarbohydrazide (BTH) and 1,4-phthalaldehyde (PD) as organic monomers. The structure and properties of BTH-PD-COP materials were characterized by Fourier transform infrared spectroscopy (FT-IR), 13C solid state NMR, scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and thermogravimetric analysis (TGA). The results show that the BTH-PD-COP material has excellent physical and chemical properties. [ABSTRACT FROM AUTHOR]

A new dynamic covalent polymer (DCP) gel was well designed and constructed based on imine chemistry. Polycondensation of 4,4′-biphenyldicarboxaldehyde and 1,3,5-benzenetricarbohydrazide via Schiff-base reaction resulted in an acylhydrazone bond gel (AB-gel) DCP. AB-gel DCP had three-dimensional network of interconnected nanoparticles with hierarchically porous structure. AB-gel DCP was successfully fabricated as a monolithic column by an in-situ chemical bonding method for online enrichment and separation purpose with excellent permeability. AB-gel DCP based monolithic column showed remarkable adsorption affinity towards target analytes including sulfonamides (SAs) and fluorescent whitening agents (FWAs) due to its strong π-π affinity, hydrophobic effect and hydrogen bonding interaction. Then, AB-gel DCP based monolithic column was applied for online separation and analysis of trace SAs and FWAs in food samples coupled with high-performance liquid chromatography (HPLC). Sulfathiazole (ST) and sulfadimidine (SM2) in one positive weever sample were actually found and determined with concentrations of 273.8 and 286.3 μg/kg, respectively. 2,5-Bis(5- tert -butyl-2-benzoxazolyl) thiophene (FWA184) was actually quantified in one tea infusion sample with the concentration of 268.5 ng/L. The spiked experiments suggested the good recoveries in range of 74.5–110% for SAs in weever and shrimp samples with relative standard deviations (RSDs) less than 9.7% and in range of 74.0-113% for FWAs in milk and tea infusion samples with RSDs less than 9.0%. AB-gel DCP monolithic column was proved to be a promising sample preparation medium for online separation and analysis of trace analytes in food samples with complex matrices. [ABSTRACT FROM AUTHOR]

• A novel methacrylate-bonded COF (TpTh-MA) monolithic column was well designed and prepared inside capillary. • The TpTh-MA monolithic column possessed excellent adsorption performance for online enrichment and analysis estrogens. • The adsorption mechanism was carefully discussed that indicated the TpTh-MA monolithic column greatly improving the extraction performance. • Online analysis method was applied for three estrogens in milk and shrimp samples that obtained satisfied results. Covalent organic frameworks (COFs) are a burgeoning class of crystalline porous materials with unique properties and have been considered as a promising functional extraction medium in sample pretreatment. In this study, a new methacrylate-bonded COF (TpTh-MA) was well designed and synthesized via the aldehyde-amine condensation reaction, and the TpTh-MA was incorporated into poly (ethylene dimethacrylate) porous monolith by a facile polymerization reaction inside capillary to prepare a novel TpTh-MA monolithic column. The fabricated TpTh-MA monolithic column was characterized with scanning electron microscope, Fourier transform infrared spectrometer, X-ray diffraction, and N 2 adsorption–desorption experiments. Then, the homogeneous porous structure, good permeability and high mechanical stability of TpTh-MA monolithic column was used as separation and enrichment media of capillary microextraction, which was coupled with high-performance liquid chromatography fluorescence detection for online enrichment and analysis of trace estrogens. The main experimental parameters influencing the extraction efficiency were systematically investigated. The adsorption mechanism for three estrogens was also explored and discussed based on hydrophobic effect, π-π affinity and hydrogen bonding interaction, which contributed to its strong recognition affinity to target compounds. The enrichment factors of the TpTh-MA monolithic column micro extraction method for the three estrogens were 107–114, indicating a significant preconcentration ability. Under optimal conditions, a new online analysis method was developed and exhibited good sensitivity and wide linearity range of 0.25–100.0 µg·L-1 with a coefficient of determination (R 2) higher than 0.9990 and a low limit of detection with 0.05–0.07 µg·L-1. The method was successfully applied for online analysis of three estrogens of milk and shrimp samples and the recoveries obtained from spiking experiments were in range of 81.4–113% and 77.9–111%, with the relative standard deviations of 2.6–7.9% and 2.1–8.3% (n = 5), respectively. The results revealed the great potential for the application of the COFs-bonded monolithic column in the field of sample pretreatment. [ABSTRACT FROM AUTHOR]

Low cycle fatigue experiments of K403 Nickel-based superalloy miniature specimens were carried out in the high temperature fatigue testing machine at 750 °C. These specimens were cut from turbine blades which were processed with hot isostatic pressing (HIP) under two different stresses, 135 MPa and 145 MPa, respectively. The geometric model of the K403 alloy was established based on the observation of its microscopic structure under the scanning electron microscopy (SEM), while its constitutive model was built based on the crystal plasticity theory. Both the fatigue experiments and the finite element analysis (FEA) indicated that the HIP process (especially 145 Mpa HIP treatment) could dramatically reduce the stress concentration and plastic deformation of K403 alloy by eliminating the internal casting defects effectively so as to extend its fatigue life at 750 °C. The SEM analysis demonstrated that the grain boundary carbides have been gradually refined. Moreover, the microstructure of γ and γ′ phase could be largely optimized, which guarantees the improvement of the alloy fatigue property. [ABSTRACT FROM AUTHOR]

Covalent organic polymers (COPs) connected by covalent bonds are a new class of porous network materials with large surface area and potential superiority in sample pretreatment. In this study, a new hydrazone linked covalent organic polymer (HL-COP) adsorbent was well-designed and synthesized based on a simple Schiff-base reaction. The condensation of 1,4-phthalaldehyde and 1,3,5-benzenetricarbohydrazide as organic building blocks led to the synthesis of HL-COP with uniform particle size and good adsorption performance. This HL-COP adsorbent with high hydrophobic property and rich stacking π electrons contained abundant phenyl rings and imine ( C N) groups throughout the entire molecular framework. The adsorption mechanism was explored and discussed based on π–π affinity, hydrophobic effect, hydrogen bonding and electron–donor–acceptor (EDA) interaction, which contributed to its strong recognition affinity to target compounds. Enrichment factors were 305–757 for six Sudan dyes by HL-COP micro-solid phase extraction (μ-SPE), indicating its remarkable preconcentration ability. Furthermore, the adsorption amounts by HL-COP μ-SPE were 1.0–11.0 folds as those by three commonly used commercial adsorbents. Then, HL-COP was applied as adsorbent of online μ-SPE coupled with high performance liquid chromatography (HPLC) for enrichment and analysis of trace Sudan dyes in food samples with detection limit of 0.03–0.15 μg/L. The method was successfully applied for online analysis of chilli powder and sausage samples. Sudan II and Sudan III in one positive chilli powder sample were actually found and determined with concentrations of 8.3 and 6.8 μg/kg, respectively. The recoveries of chilli powder and sausage samples were in range of 75.8–108.2% and 73.8–112.6% with relative standard deviations of 1.2–8.5% and 1.9–9.4% ( n = 5), respectively. The proposed method was accurate, reliable and convenient for the online simultaneous analysis of trace Sudan dyes in food samples. [ABSTRACT FROM AUTHOR]

The carbonaceous-siliceous-argillitic rock type uranium deposit in the Zoige area is located in the northeastern margin of the Tibetan Plateau, and has gained much attention of many geologists and ore deposit experts due to its scale, high grade and abundant associated ores. Because of the insufficient reliable dating of intrusive rocks, the relationship between mineralization and the magmatic activities is still unknown. In order to study this key scientific issue and the ore-forming processes of the Zoige uranium ore field, the LA-ICP-MS zircon U-Pb dating of magmatic rocks was obtained: 64.08±0.59 Ma for the granite-prophyry and ∼200 Ma for the dolerite. U-Pb dating results of uraninite from the Zoige uranium ore field are mainly concentrated on ∼90 Ma and ∼60 Ma. According to LA-ICP-MS U-Pb zircon dating, the ages for the dolerite, porphyry granite and granodiorite are 200 Ma, 64.08 Ma approximately and 226.5-200.88 Ma, respectively. This indicates that the mineralization has close relationship with activities of the intermediate-acidic magma. The ages of the granite porphyry are consistent with those uraninite U-Pb dating results achieved by previous studies, which reflects the magmatic and ore-forming event during the later Yanshanian. Based on the data from previous researches, the ore bodies in the Zoige uranium ore field can be divided into two categories: the single uranium type and the uranium with polymetal mineralization type. The former formed at late Cretaceous (about 90 Ma), while the latter, closely related to the granite porphyry, formed at early Paleogene (about 60 Ma). And apart from ore forming elemental uranium, the latter is often associated with polymetallic elements, such as molybdenum, nickel, zinc, etc. [ABSTRACT FROM AUTHOR]

Highlights: [•] Preparation of sulfonated graphene/polypyrrole coating by in situ electropolymerization. [•] High extraction selectivity and capacity to volatile terpenes. [•] Practical application for analysis of trace terpenes from spice samples. [ABSTRACT FROM AUTHOR]

Highlights: [•] An overview of online sample preparation techniques coupled with LC is presented. [•] The coupling approaches and corresponding interfaces are discussed. [•] The problems and expected trends in this field are attempted to be discussed. [ABSTRACT FROM AUTHOR]

• The characteristics of microstructure with different casting processes are described. • The tests are carried out on specimens cutting from blades instead of standard specimens. • The models of the grains have been established, inter-grain interaction has been analyzed. • Viscoplastic constitutive equation has been established considering the microstructure characteristics. • The prediction of K480 creep lives with different microstructures has been realized. Creep experiments were performed on miniature K480 nickel-based superalloy specimens at 835 °C and 400 MPa. These specimens were cut from turbine blades processed with different casting processes and pouring temperatures. The microstructure analysis, fracture morphology analysis, and grain size analysis were carried out by scanning electron microscopy (SEM), indicating that the influence of the moulding process and pouring temperature on the microstructure of the alloy is mainly reflected in the difference in the size of crystal grains, grain boundary precipitates and casting defects, which in turn affects the high temperature creep properties of the alloy. Based on crystal plasticity theory, a polycrystalline alloy viscoplastic constitutive equation considering the moulding process and pouring temperature parameters is established, meanwhile, the geometric models of the K480 alloy were established based on the observations of its microscopic structure under SEM. The study revealed the relationship between the casting process of the blade, the microstructure of the material, and the creep property of the specimen. The established plastic constitutive model can predict blade stress rupture life under different casting processes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ore-forming materials were sourced from the Niutitang Formation and deep crust. • Ore-forming fluids were derived from meteoric water. • Redox and fluid-rock reaction caused ore precipitation. • Tectonic system and overprinting zone of black-red alterations are indicators for prospecting. The Baimadong uranium deposit is situated in the Yangtze Craton, SW China, and is one of the most representative carbonate-hosted uranium deposits in China. Uranium mineralization has spatial and genetical relationships with black and red alterations that has been documented by previous studies. However, the signature, source, and evaluation of ore-forming fluids producing the alterations and mineralization remain poorly understood. Fluid inclusions hosted in different generations of hydrothermal calcite have been analyzed in this study, including Cal 1 (pre-ore stage), Cal 2 (early ore stage), and Cal 3 (main ore stage). Three types of fluid inclusions were identified: liquid-dominated biphase, vapor-dominated biphase, and vapor-only monophase. Based on fluid inclusion microthermometry using the FIA method, the fluids associated with Cal 2 are characterized by relatively higher temperature (∼243 ℃) and salinity (5.3 wt% NaCl equiv.) compared with fluids associated with Cal 1 (T h = ∼221 ℃; Salinity = 1.9 wt% NaCl equiv.) and Cal 3 (T h = ∼144 ℃; Salinity = 2.5 wt% NaCl equiv.). The results of stable isotopes (C, O, and S) indicate that the carbon in pre-ore stage fluids was dominantly originated from host marine carbonate rocks (δ13C fluid-PDB = −3.0 to 0.5 ‰; δ18O fluid-SMOW = 4.8 to 11.3 ‰), the carbon and sulfur in early ore-forming fluids were mainly derived from the Niutitang Formation with minor from deep crust (δ13C fluid-PDB = −11.2 to −8.4 ‰; δ18O fluid-SMOW = 7.9 to 11.4 ‰; δ34S v-CDT = −11.3 to + 2.1 ‰), whereas the main ore-forming fluids were sourced from meteoric fluids (δ13C fluid-PDB = −8.6 to −4.9 ‰; δ18O fluid-SMOW = 0.4 to 8.6 ‰). These results reveal that redox reaction as well as fluid-rock reaction are key factors controlling the large-scale uranium mineralization at Baimadong. Combined with these observations, geological setting, and previous geochemical features, we suggest that tectonic system together with overprinting zone of black and red alterations are indicators for exploration of carbonate-hosted uranium deposit in South China and elsewhere worldwide. [ABSTRACT FROM AUTHOR]

The Datian uranium deposit is a migmatite-hosted, high temperature, hydrothermal deposit in the Kangdian region. Detailed information on the chemical composition and formation age of the uraninite remains lacking, which impedes our understanding of uraninite genesis. Two phases of uraninite have been identified according to their relationships with other minerals and their field relationships. The phase 1 (Ur1) uraninite is characterized by local development of microfractures and pores in the crystal of uraninite, a scattered distribution, and irregular crystal shapes, and it is associated with ilmenite, biotite, and rare earth element (REE) minerals (monazite and xenotime). The phase 2 uraninite (Ur2) has anhedral crystal shapes with well-developed microfractures and pores and is associated with pyrite, albite, pyrrhotite, molybdenite, zircon, and chlorite. X-ray element mapping revealed that the distributions of U, Th, and Pb in the Ur1 uraninite are homogeneous, whereas those in the Ur2 uraninite are heterogeneous. The results of the electron microprobe analysis (EMPA) show that the UO2 and PbO contents of the Ur1 and Ur2 uraninite do not vary significantly. The high ThO2 contents of the Ur1 (1.08–1.68 wt %) and Ur2 uraninite (3.41–4.83 wt %) indicate that they formed at different temperatures. The laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis results show that the ∑REE of the Ur1 uraninite (3747.5–7032.3 ppm) is lower than that of the Ur2 uraninite (8369.2–11,484.3 ppm), and the REE patterns of the Ur1 and Ur2 uraninite are sickle-shaped with large negative Eu anomalies. The LA-ICP-MS U–Pb dating results revealed that the ages of the Ur1 (841.4 ± 4.0 Ma) and Ur2 (834.5 ± 4.1 Ma–837.2 ± 4.5 Ma) uraninite are in consistent with that of the migmatite. Thus, the Datian uranium deposit underwent at least two hydrothermal events, and the uraninite was formed due to the migmatization. [ABSTRACT FROM AUTHOR]

• Investigated the influence of sliver defects on the creep rupture life of nickel-based single crystal superalloys. • Revealed the damage mechanism of sliver defects on the creep life of single crystal superalloys through SEM and EBSD observations. • Developed creep constitutive equations for specimens containing sliver based on crystal plasticity theory, explaining the reasons for the decrease in sample life caused by sliver. • Predicted the damage tolerance of sliver defects with different orientations. Sliver defects are common casting imperfections in the preparation of single crystal blades, significantly impacting the high-temperature mechanical performance of blades and potentially leading to blade failure. A detailed study was conducted on the microstructure of sliver in the second-generation nickel-based single crystal superalloy CMSX-4, focusing on its influence on creep performance at 980 °C/250 MPa. Results indicate a substantial impact of sliver on the creep performance of single crystal superalloys, with a 26.37 % reduction in creep rupture time for samples with sliver compared to those without. Fracture analysis reveals that sliver primarily contributes to performance deterioration by promoting the extension of grain boundary microcracks through grain boundary sliding during the creep process, accelerating sample fracture. Utilizing crystal plasticity theory, a successful fit was achieved for the creep rupture life of samples with sliver, allowing the prediction of fracture life for samples with different orientations of slivers. Predictive results suggest that, for CMSX-4 alloy, the orientation of the sliver should be restricted to within 8°. [ABSTRACT FROM AUTHOR]

Due to the small size of uranium minerals, the occupations of U4+ and U6+, Th and Pb in uraninite is little studied. The coarse giant uraninite (CGU) from Miyi with size up to 1 cm is one of the best samples for studying uraninite mineralogical property. CGU mainly composed of UO2, ThO2, PbO, CaO. There are three forms of occurrence of U, namely UO2, UO3, and UO2+x; and impurity such as ThO2, PbO, CaO may entering the mineral lattice, which can affect mineral properties and facilitate the chemical reactions during mineralization and leaching processes. [ABSTRACT FROM AUTHOR]

The platinum group elements (PGE) in the mafic-ultramafic suite in the Xinjie layered intrusion and associated basalts and syenites were analyzed using neutron activation techniques after fire-assay preconcentration. On this basis, the geochemistry of the platinum group during the magmatic stage is discussed. With respect to PGE distribution, the Xinjie layered intrusion is similar to the Bushveld ferruginous ultramafic series and is distinct from komatiite and Alpine-type peridotite. It is also similar to the Emeishan basalt in PGE characteristics, implying that the original magmas of them may be of the same type. [ABSTRACT FROM AUTHOR]

Here new evidence of the isotope geochronology and the geochemistry from the Yuanmou-Miyi complexes reveal the Precambrian tectono-magmatism geodynamic process in the study area. The Yangtze Block basement with 1.81- ~1.77 Ga and negative εHf(t) values of −7.8 to −0.7 corresponded to the assembly of the Columbia-supercontinent. However, the rifting magmatic event of ~ 1.70 Ga, which caused the continental crust extension-thinning in the study area, may exert influence on the subduction-magmatism in the Grenvillian period. The Yuanmou-Miyi complexes of 1.19- ~1.00 Ga are characterized by (La/Sm)N＞1, depletion in HFSEs, negative anomalies of Nb-Ta, and enrichment of LILEs, which show a genetic link with the subduction-magmatism. The temporal tendency that the magmatism from Yuanmou to Miyi gradually became younger, may be responsible for the subducting direction. The subduction caused the reactivation of the Anninghe-Lvzhijiag fault zone, and created the rupture windows of the subduction slab, leading to upwelling of the deep magma. These granitoids were derived from the partial melting of the mantle wedge, while the small-scale gabbro dikes intruded into the granitoids were likely spillover products from the asthenosphere mantle melts through the rupture windows. [ABSTRACT FROM AUTHOR]

• Baimadong U deposit is hosted by carbonate rocks and is associated with black and red alterations. • Black alteration is characterized by exogenous graphite and bitumen. • Red alteration is marked by precipitation of hematite and goethite. • Black alteration provides reducing agents for, and red alteration results from, U mineralization. The Baimadong uranium deposit is hosted in carbonate rocks that were subjected to extensive black and red alterations, silicification and argillization, and is assigned to the carbonaceous-siliceous-pelitic rock-type uranium deposits in the Chinese literature. However, the nature of the mineralization, especially the black and red alterations and their relationship with uranium mineralization, remains poorly understood. Petrographic and Raman spectroscopic studies indicate that the black material are organic matter mainly composed of graphite and bitumen, whereas the red-altered rocks are characterized by abundant iron oxides. Crosscutting relationships suggest that the black alteration occurred before the red alteration. Comparison of whole-rock geochemistry between the different types of rocks suggests that total organic carbon (TOC), U and total organic sulfur (TOS) were gained through the black alteration, and FeOT was gained through the red alteration, whereas total inorganic carbon (TIC), CaO and MgO were lost in both types of alterations. The δ13C org (PDB) values and biomarker characteristics of the black-altered rocks suggest that the organic matter was derived from the black shale of the Niutitang Formation underneath the deposit. U enrichment is associated with both the black and red alterations, and shows positive correlations with Al 2 O 3 , K 2 O, TiO 2 , SiO 2 , TOC and TOS. It is proposed that the uranium mineralization at Baimadong resulted from superposition of two fluid events controlled by a common structural system. First, petroleum generated in the black shales of the Niutitang Formation and hydrothermal fluids migrated along cross-formational faults to the carbonate rocks of the Qingxudong and Shilengshui formations, causing the black alteration and preliminary uranium enrichment. Second, an oxidizing, U-bearing fluid flowed through the same structure and precipitated uraninite through reaction with the black-altered rocks, accompanied by precipitation of hematite and goethite as marked by the red alteration. The combination of black and red alterations with major faults may be used as a mineralization indicator in the exploration of this type of U deposits. [ABSTRACT FROM AUTHOR]

The Shitoukengde Cu-Ni deposit is located in the eastern part of the East Kunlun Orogenic Belt (EKOB). The overall complex underwent emplacement into the surrounding rock, including the gneiss and marble. The ore-bodies exist in complex I, which is composed of peridotite, pyroxenite, and gabbro. The petrogeochemical characteristics of the rocks show that the m/f values range from 1.93 to 5.97, and the Fe3+/ΣFe ratios of the spinel are < 0.3, indicating that the Shitoukengde complexes have the potential to form a Cu-Ni ore deposit. Based on the evidence of marble and gneiss xenoliths, there are higher CaO and Al2O3 contents in the peridotite and pyroxene, there are Nb and Ta depletions, in the Shitoukengde; these results indicate that the ore-forming parental magma has been obviously contaminated by crustal material during the evolution process and that the materials responsible for the contamination mainly originated from the middle-upper crust. The mafic-ultramafic complex, which is closed to marble, has higher CaO and Al2O3 contents; higher (87Sr/86Sr)i values and lower Ni contents; thus, it is reasonable to infer that the Shitoukengde mafic-ultramafic rocks assimilated some marble, and the contamination of marble without sulfide suppresses the sulfide saturation. The pyroxenite with better mineralization is mainly orthopyroxene, and the increase in the sulfur isotope values in the pyroxenite and peridotite is accompanied by an increase in the Ni content; these results suggest that the SiO2 and S of biotite-plagioclase gneisses, especially the S addition, were important for the Shitoukengde intrusion to reach sulfide saturation. The whole-rock Ni content in the peridotite shows a positive relationship with the FeO content of spinel, indicating that the crystallization of spinel has little effect on sulfide saturation. The capable of crystallizing olivine with Fo content as high as 89.3 mol% and olivine Fo value exhibits a positive relationship with the olivine NiO content, indicating that olivine fractional crystallization did not play a significant role in sulfide saturation. The δ34SV-CDT value of the giant Xiarihamu deposit is much higher than that of Shitoukengde. The degree of crustal S contamination is probably responsible for the difference in the scale and ore grade of the Cu-Ni sulfide deposits in the East Kunlun area. The above indicators could guide the exploration and evaluation of similar deposits in the EKOB. [ABSTRACT FROM AUTHOR]

The dolostone reservoir of the Middle Permian Maokou Formation in Eastern Sichuan has good prospects for oil and gas exploration. Study of dolomitizing genesis of the Maokou Formation is essential for predicting the distribution of the dolostone reservoir. Petrography, in situ geochemistry, Sr-Mg isotopes, and fluid inclusions were carried out on samples from the Maokou Formation in Eastern Sichuan in order to discuss the dolomitizing process. Based on mineral and textural characteristics, dolomites were divided into four components: partially clouded dolomite (PCD), mosaic-like dolomite (MLD), cloudy-centered and clear-rimmed dolomite (CACD), and saddle dolomite (SDD). Results indicate that the Maokou Formation in Eastern Sichuan mainly experienced two stages of dolomitization. PCD, MLD, and cloudy-centered dolomite (CCD) were formed during the early dolomitization. They all show turbid crystal planes and bright orange-red CL and have similar trace element contents, 87Sr/86Sr ratios, and rare-earth patterns, indicating that they might be formed in the same fluid. This is a period when dolomitizing fluids mainly migrated along pores or microcracks and replaced protogenetic calcites, which occurred in the shallow burial stage of the Maokou Formation before the Late Permian. Clear-rimmed dolomite (CRD) and SDD were formed in the late stage of dolomitization. They all have clean crystal planes and darkly red CL. CRD of the ERY profile has trace element contents, 87Sr/86Sr ratios, and rare-earth patterns similar to SDD of the HLCH profile and Well TL6, inferring that both may be formed in the same fluid. Combined with high SrO contents and homogenous temperatures of fluid inclusions of CRD and SDD and Mg-isotopic compositions, they were generated by hydrothermal dolomitization. The hydrothermal fluid stage is related to the movement of the Emeishan Large Igneous Province, which was made up of basaltic magmatic fluids mixing with the surface water. The hydrothermal fluid mainly migrated upwards along structural fractures or faults and filled in structural fractures, occurring in the Late Permian to Middle-Late Triassic. [ABSTRACT FROM AUTHOR]

The article discusses the geological features and metallogenic process of the Erligou Gold Deposit, Sichuan Province, China. Topics discussed include presence of magmatic activities and favorable geographical setting for ore controlling; exposure of gold bearing quartz veins to groundwater; and display of toughness by the ore-bearing deposits in compression shear stress from different directions.

The article discusses the mineralization process of Huangjinping Gold Deposits in China. Topics discussed include testing of samples of trace elements such as quartz, pyrite and granitic mass; display of low rare earth elements pattern by auriferous pyrites; and formation of stable fracture surface by granite pluton under compressive stresses.

The article focuses on a study that investigates geochemical characteristics of rare earth elements (REE) of Baijintaizi gold deposit in Kang Ding County, Si Chuan Province, China. The study mentions that granite, silicide granite shows strongly negative Europium (Eu) anomaly whereas pyrite and quartz mineral of gold-bearing quartz vein in the deposit shows positive Eu anomalies. Also the study reveals that the deposit may be associated with deep magma.

The article discusses the research study conducted to examine the geological features and genesis of Scheelite Deposit in Pingtan, Chengbu County, Hunan Province, China. Topics discussed include exposure of magmatic rock, stratum, and ore structure, genesis of mineral deposits and tectonic fracture zone, and metasomatic deposit.

The article discusses a study that focuses on the results of Tibetan Mineral Resources Potential Assessment Project based on the analysis and research of multi-source information data of Nixiong and Jiangla skarn iron ore forecast in Gangdese magmatic arc in Tibet, China. Topics discussed include analysis of iron mineralization law; processing of geological, geophysicalCgeochemical data; and application of Prediction Auxiliary System of Geologic Volume Method in resource reserve estimation.

[Display omitted] • Co-existing pyrite and calcite with uranium minerals play a significant role in ISL of uranium. • Gypsum produced by pyrite and calcite in CO 2 + O 2 environment disadvantages the leaching of uranium. • Secondary hexavalent uranium minerals will be produced in the ore layer of a neutral environment. Oxidative weathering of pyrite, a widespread iron sulfide mineral, is crucial for the uranium mineralization in sandstone-hosted uranium deposits and the ore utilization leaching under manual intervention. To understand the behavior of pyrite under CO 2 + O 2 leaching conditions in sandstone-hosted uranium deposits, samples of uranium ore from the mineralized zone of the Qianjiadian IV uranium deposit located in the lower section of the Yaojia Formation were collected for this study. The stirring leaching experiment was carried out through the processes of the pyrite-bearing uranium ore samples thinned before and after the reaction, followed by an optical microscopic study and the TESCAN Integrated Mineral Analyzer analysis, and finally, the thermodynamic simulation by making use of PHREEQC3.0. The results revealed the following: (1) The dissolution particles of pyrite become smaller, which may increase the porosity of the ore layer and the exposure ratio of uranium minerals. And more soluble pyrite with a high free surface will be more competitive with uranium minerals for the consumption of O 2. (2) The ion (Fe2+) produced by the dissolution of pyrite will be oxidized to Fe3+ by excess O 2 (4 mol), which provides an oxidant for the oxidation of uranium minerals, and the generated SO 4 2- will combine with the Ca2+ released from calcite to form a permanent precipitate of gypsum, which may block pores and cover the uranium ore. (3) Pyrite and calcite will consume O 2 and CO 2 in the injection system, thus jointly inhibiting the leaching of uranium minerals. After the injection of excessive CO 2 and O 2 , the concentration of Ca2+, SO 4 2-, Fe3+, UO 2 2+, and HCO 3 – in the system will continue to accumulate, resulting in the secondary precipitation of calcite, co-precipitation of gypsum, iron minerals, colloids, and hexavalent uranium minerals, resulting in plugging pores and seriously affecting the effective leaching of uranium. This study contributes to the understanding of the behavior of pyrite during uranium recovery through CO 2 + O 2 leaching. It also contributes to the understanding of quantitative uranium mineralization in sandstone-hosted uranium deposits and process parameters in in-situ leaching (ISL) of uranium. [ABSTRACT FROM AUTHOR]

Vanadium is a trace element widely distributed in the Earth’s crust. Naturally high levels of vanadium are recognized mainly in basic rocks and minerals, particularly in titaniferous magnetite. And the anthropogenic sources of vanadium include fossil fuel combustion and wastes including steel-industry slags. In the last few years, the authors have made investigations and assessments on the environmental geochemistry and ecological risk of vanadium in the Panzhihua mining and smelting area. In the study area, anthropogenic vanadium resulted from mining, extracting and smelting of V-Ti magnetite; vanadium pollution of topsoil and sediments occurs mainly in the mining and extracting area, smelting area, slag dumping area, tailing dam and coal mining area. In the soil, the chemical speciation of vanadium shows: insoluble residue > organically bound > Fe (amorphous) oxide-bound > Mn oxide-bound > soluble component. Vanadium pollution can cause potential harmful effects on ecological systems, and lead to animal poisoning and human disease. So vanadiam pollution should be monitored on a regular basis in the Panzhihua area. [ABSTRACT FROM AUTHOR]

Understanding the thermal stability of ceramic matrix composites is one of the necessary prerequisites for their engineering application. This study aimed to investigate the stress response and failure mechanism of SiC-coated C f composite during thermal shock in an O 2 free environment, at temperature between 500 and 1800 °C. Composites with a single layer of SiC coating, and a reinforcing phase are carbon fiber yarns with a three-dimensional four-step braided structure. A meso-scale finite element model considering the orientation of fiber yarns was established to analyze thermal residual stress (TRS) and thermal shock stress (TSS) by transient analysis. Results indicated that the most dangerous position generated by the TRS was in the matrix close to the fiber yarn/matrix interface. Initial cracks first nucleated in the matrix, because the matrix was subjected to large residual compressive stress along the braiding direction, which is related to the distribution characteristics of the fiber yarns (braiding method). Fiber yarns with different orientation exhibited almost the same stress state, and interaction between fiber yarns resulted in a similar "twisted" state. For single fiber yarns, the principal axis and fiber yarn/fiber yarn interface were prone to failure. TSS in the composites rapidly increased during the initial cooling stage. A sudden change in temperature and stress gradient led to cracking and peeling at the composites/coating interface. Possible failure modes and mechanisms of the composites with and without the SiC coating are discussed. [ABSTRACT FROM AUTHOR]

• Based on continuous damage mechanics, a new damage evolution law of anisotropic nickel-based single crystal materials is proposed. • Based on the crystal slip theory, creep resistance τ r e s (α) is innovatively introduced and the modified creep constitutive model of nickel-based single crystal superalloy is presented. • An anisotropic creep life prediction model for single crystal superalloy was established. The combination of macroscopic creep deformation and microscopic crystal slip is realized. • The creep parameters A, n, Q and τ r e s (α) are obtained by fitting on the basis of the slip theory of finite deformation crystals and test results. • The creep behavior of anisotropic Ni-based single crystal superalloy is simulated, the accuracy of life prediction is within 1.2 times data dispersion band. The current study is centered on the creep anisotropy of a nickel-based single crystal superalloy across a wide temperature range and with orientations of [001], [011], and [111]. Based on continuous damage mechanics, a new damage evolution law of anisotropic nickel-based single crystal materials is proposed. Based on the crystal slip theory, creep resistance is innovatively introduced and the modified creep constitutive model of nickel-based single crystal superalloy is presented. Meanwhile, in order to facilitate engineering application, an anisotropic creep life prediction model for single crystal superalloy was established based on continuous damage mechanics and crystal plasticity theory. By establishing the relationship between deformation gradient and shear strain rate on the sliding system, the combination of macroscopic creep deformation and microscopic crystal slip is realized. According to the working state of single crystal blade, a wide range of temperature creep tests at different load points were carried out. The creep parameters A (temperature dependent parameter), n (apparent stress index), Q (apparent activation energy) and τ r e s (α) (creep resistance) are obtained by fitting on the basis of the slip theory of finite deformation crystals and test results. The creep behavior of anisotropic Ni-based single crystal superalloy is simulated by using a modified life prediction model considering creep resistance in finite element framework, and the numerical results are compared with the experimental results. The results show that the constitutive formula proposed in this paper can be used to simulate the mechanical properties of Ni-based single crystal superalloys at different orientations in the wide temperature range, and the constitutive formula also can accurately predict the creep life and creep deformation with different temperatures and directions. The life prediction error is in the range of 1.2 times. [Display omitted] [ABSTRACT FROM AUTHOR]

• Elevated U concentrations (up to 266 ppm) were found in the Lala IOCG ores. • Uraninite, uranothorite, polycrase and coffinite were recognized. • Uranium was initially enriched with Cu, Mo, Th and REE at ca. 1086 to 1053 Ma. • U and Mo were remobilized and re-enriched together at ca. 888 to 828 Ma. Elevated uranium concentrations have been reported in many IOCG deposits, but detailed information about the occurrences of uranium minerals and their relationships with other minerals remains scarce, which hinders understanding of the mineralization mechanisms and the nature of the association of these metals. This paper reports a new case of uranium enrichment in an IOCG system, the Lala Cu-Fe deposit in the Kangdian region, SW China. Whole-rock analyses of ores and barren rocks yielded highly variable U concentrations ranging from 0.76 to 266 ppm. Uranium shows a strong positive correlation with Mo, broadly positive correlations with Cu and ΣREE, and a vague, negative correlation with Th. Four uranium minerals, uraninite [UO 2 , uranothorite [(Th,U)SiO 4 , polycrase [(Y,Ca,Ce,U,Th)(Ti,Nb,Ta) 2 O 6 , and coffinite [U(SiO 4) 1-x (OH) 4x , were identified. The uraninite is divided into two phases: phase 1 (Ur1) characterized by corroded or irregular crystal shapes, and phase 2 (Ur2) showing well-developed, subhedral to euhedral crystal shapes. Ur1 is interpreted to be formed in the primary Cu – Fe – Mo – REE – U mineralization, together with the bulk of Cu and other metal sulfides, as well as other U and REE minerals, including uranothorite, polycrase, bastnäsite and xenotime, and accompanied by K-alteration (K-feldspar and biotite). Ur2 is interpreted to be formed in a secondary hydrothermal event characterized by introduction of fluorite and carbonates, in which U and Mo, and to lesser extent Cu and REE, were remobilized, while Th remained relatively stable. The primary mineralization is inferred to have taken place in a period from ca. 1086 to 1053 Ma based on previous Re-Os geochronology, and the secondary mineralization (remobilization) likely took place from ca. 888 to 828 Ma, as suggested by uraninite chemical ages obtained in this study and other published geochronological data. These ages correspond to tectonomagmatic events taking place in generally extensional environments, in the western margin of the Yangtze Block during the Meso- to Neoproterozoic time. The Lala Cu-Fe deposit represents a new case of IOCG deposits with U (and REE) enrichment, the economic potential of which warrants further examination. [ABSTRACT FROM AUTHOR]

The article presents a study which discusses geological and geochemical evolution of forming of kalium-rich brine in Sichuan Basin in China. Topics discussed include effects of numerous distinct tectonic events on salt brine reservoir in Sichuan Basin, varied ion concentration of sea water due to sea water evaporation, occurrence of small amount of evaporites, and occurrence of celestite precipitate.

• Clay minerals and carbonate cementation are associated with U mineralization. • δD and δ18O values of clay minerals suggesting meteoric origin of the ore fluid. • Hydrocarbons may have played an important role in U mineralization. • H-O-C isotopes suggest a transient interface between oxidizing/reducing fluids. The Meso-Cenozoic Yili Basin in northwestern China hosts important uranium and coal resources. The uranium deposits are mainly hosted by sandstones and are characterized by clay and carbonate alterations within and surrounding the orebodies. H-O-C isotopes of clay minerals and carbonate cement in the different alteration zones of the uranium deposits in the southern margin of the Yili Basin are summarized to examine the mechanisms of uranium mineralization. The alteration zones associated with the uranium mineralization include an intensely oxidized zone, a weakly oxidized zone, a transitional (mineralization) zone, and a reduced zone. The δD and δ18O values of the parent fluids calculated from clay minerals from the different alteration zones show a linear trend that intersects the global meteoric line at a point with a δ18O V-SMOW of ca. −5‰ and a δD V-SMOW of ca. −30‰, which coincide with the upper end of the δD – δ18O trend (along the meteoric line) of formation waters in the basin, suggesting that the uranium mineralizing fluid was of meteoric origin. The general trends of decreasing δD and δ13C and increasing δ18O from the intensely oxidized zone to the reduced zone, together with the fact that calculated δD V-SMOW values of the mineralizing fluids are lower than the original meteoric fluid, and that the δ13C values of the calcite cement overlap with those of organic matter in sedimentary rocks, suggest that hydrocarbons were involved in uranium mineralization. The hydrocarbons may have been important reducing agents causing precipitation of uranium minerals. The hydrogen ion released from oxidation of the hydrocarbons may have been buffered by the formation of clay minerals, which favors co-development of clay alteration and calcite cement. Deviation of H-O-C isotopes from the general variation trends as expected from the above redox mechanism likely resulted from the dynamic nature of the redox front, which changed its position in response to hydrodynamic balance between a downward flow of uranium-bearing, oxidizing fluid and an upward flow of reductants-bearing, reducing fluid from the lower part of the basin. [ABSTRACT FROM AUTHOR]

• A creep test piece of the PDL cooling structure applied in turbine blade is designed. • The creep macro–micro fracture mechanism of the PDL cooling structure is revealed. • A creep life prediction model of the PDL cooling structure is established. This article investigates the high-temperature creep macroscopic and microscopic fracture mechanism of the porous double layer (PDL) cooling structure through experiments, and predicts the creep life of the structure using the back propagation (BP) neural network model based on the bone point stress method. The high temperature creep fracture of the PDL cooling structure is determined by the macro structure characteristics and the microstructure properties. Impingement holes and effusion holes, as stress concentration region, provide a place for crack initiation. The crack growth rate of effusion plate is greater than that of impingement plate. When the creep crack extends to a certain length, the effusion plate breaks first, and then the impingement plate breaks instantaneously. At the interface between carbide and matrix, microcracks are prone to occur due to stress concentration and inconsistent deformation, thereby promoting the initiation and propagation of macroscopic cracks. The BP neural network model based on the bone point method has a good prediction result for the creep life of the PDL cooling structure, and the maximum prediction error is 9%. [ABSTRACT FROM AUTHOR]

• In the non-isothermal creep stage, the Δε increases exponentially with the increase of the T over. After this stage, the Δε has a tendency to fall, and the material shows a new second stage of creep. • The greater the cumulative plastic deformation of the material at the end of the overheating phase, the shorter the creep life. High temperature can provide more thermal activation energy, which makes atomic diffusion easier, thus promoting rafting of γ′ phase. • The residual creep life t res gradually decreases exponentially with the increase of T over. In addition, the greater the T over , the greater the creep rate after non-isothermal. • A new creep constitutive model was proposed based on the crystal plasticity theory. Nonisothermal service conditions are one of the main abnormal failure modes of aero-engines. The creep tests of a Ni-based directionally solidified superalloy under nonisothermal creep conditions (T over = 980 °C, 1000 °C and 1020 °C) and constant load (σ = 227 MPa) were analyzed by SEM. According to the creep tests, we calculate the key creep parameters. By studying tests interrupted at different stages of creep, the microstructure evolution law is obtained. Based on the above research, an improved constitutive model is proposed. The creep behavior under different T over is simulated and calculated. The simulation results are in good agreement with the experimental results. [ABSTRACT FROM AUTHOR]

The article offers information on the mineralization process of the Changdagou Porphyry Copper Deposits in Dege, Sichuan Province in China. Topics discussed include the petrological and geochemical study of the porphyry pluton indicating the geochemical characteristics of the porphyry similar to the properties of the adakites, the ore-bearing pluton and granite porphyry consisting of mantle formed by magma, and hydrothermal fluids formed in the process of emplacement.

The article discusses the research study conducted to examine the geologic history of the iron oxide copper gold (IOCG) deposits in Southwestern China that was associated with polymetallic mineralization. It reveals the age of magmatic rocks and metallogenic epoch and the coupling relationship between polymetallic elements. It also reveals the ore-forming process including the volcanic sedimentation, grenville orogenic event, and superimposed mineralization.

The mechanical properties of nickel-based single-crystal superalloys are sensitive to temperature and orientation. The present work focuses on the stress and strain responses of a second-generation nickel-based superalloy at different temperatures and with different orientations. Microstructure and dislocation arrangements are observed by scanning and transmission electron microscopy of samples after tensile testing. The results reveal the tensile fracture failure modes and dislocation morphologies (braids, cells, stacking faults, etc.) for different temperatures and orientations. Although the [001] sample shows higher yield strength than the other two orientations, the strain hardening was more significant at [111] orientation and stress softening at [011] orientation due to their different dislocation mechanisms. In addition, a new hardening model and damage evolution law are proposed and coupled with a crystal plastic constitutive model. Numerical analysis results show that the proposed constitutive model can accurately fit the full stress-strain response from tensile experiments for different temperatures and orientations. [ABSTRACT FROM AUTHOR]

• Indosinian magma-related Mo mineralization was confirmed. • The Mo mineralization in the Cuojiaoma took place at ∼210 Ma. • Mixture of crustal- and mantle-derived magma formed the Cuojiaoma batholith. • There could be more prospective Mo resources in northern YDT. Subduction of oceanic plates beneath continental lithosphere is critical for understanding tectonic evolution and evaluation of prospecting and exploration. Within the Yidun Terrane (YDT) of southwestern China, a number of Mesozoic to Cenozoic granitoid intrusions are exposed and they are useful for investigating the tectonic evolution of the Paleo-Tethys system. However, Mesozoic magmatism of the northern portion of the YDT, remains ambiguous regarding to their magmatic spatial–temporal evolution and their mineralization potential. As the largest pluton in the northern YDT, the Cuojiaoma batholith mainly consists of monzogranite and granodiorite. In this study, we present new zircon U–Pb and molybdenite Re–Os ages, whole-rock geochemical, and zircon Hf–O isotopic data for the Cuojiaoma batholith. LA-ICP-MS zircon U-Pb dating of granodiorite and monzogranite exhibit ages of 221.8 ± 1.4 Ma (n = 22, MSWD = 2.4) and 216.7 ± 2.2 Ma (n = 14, MSWD = 0.03), respectively. A total of 9 molybdenite samples differing Re-Os model ages of 205.4 ± 3.3 and 220.6 ± 5.5 Ma, yield a robust weighted mean model age of 209.9 ± 1.8 Ma (MSWD = 2.4, n = 9) representing the depositional age of molybdenite. The monzogranite and granodiorite's mineralogical and geochemical characteristics indicate they are classified as (medium-) high-K calc-alkaline and metaluminous to weakly peraluminous I-type granite. Geochemically, they are enriched in large-ion lithophile elements (LILEs, e.g., Rb, U, K) and light rare earth elements (LREEs), and depleted in high-field-strength elements (HFSEs, e.g., Nb, Ta, Ti and P) and heavy rare earth elements (HREEs), and contain distinctly or slightly negative Eu anomalies and no significant Ce anomalies, indicating an affinity to classical island arc magma. Combined with their negative zircon ε Hf (t) values (−16.24 to −2.49 and −16.41 to −1.43) and two-stage Hf model ages (2019–1255 Ma and 2027–1200 Ma), plus their zircon δ 18O values, which range from 5.96 to 8.01 and from 5.05 to 7.61 for monzogranite and granodiorite, respectively, these geochemical indexes indicate that the Cuojiaoma batholith shares similar petrogenesis to other intrusions within the YDT. The formation of the early granodiorite may be genetically related to the slab subduction and is most likely formed by mixture of lower crustal melts and mafic magma derived from partial melting of mantle wedge induced by the influx of slab derived melt (fluid). Subsequent slab break-off and the upwelling asthenosphere at ∼ 216 Ma to 210 Ma led to high heat flow and extensive melting of the overlying mantle wedge, followed by the highly crystallization differentiation, which finally contributed to the monzogranite and the subsequential disseminated molybdenite in a post-subduction extension setting. The northern YDT possesses high Mo metallogenic prospectivity, especially for the magmatic activity that dominantly by lower crustal melt and genetically related to the slab break-off occurred at ∼ 216 Ma and represented by the highly fractionated granite derived from the large Cuojiaoma granitic batholith. [ABSTRACT FROM AUTHOR]

• A a novel covalent organic polymers (AB-COP) is firstly prepared. • AB-COP is firstly used to purify biflavonoids from Selaginella doederleinii. • Properties, performance and mechanism are investigated comprehensively. • 4.Compared with commonly used materials, AB-COP has excellent enrichment effect. • New purification method is developed for biflavonoids from natural products. Herein, a novel covalent organic polymers (COP) material based on acylhydrazone bond (AB-COP) was prepared as an efficient extraction material for enriching natural medicine biflavonoids from Selaginella doederleinii Hieron. The obtained AB-COP structure was characterized in detail. And it was the first time to investigate the effect of AB-COP on the adsorption of biflavonoids. The effects of initial concentration of solution, adsorption temperature, solid-liquid ratio, adsorption time on the adsorption of biflavonoids were studied. In addition, adsorption kinetic model, adsorption thermodynamic model and density functional theory (DFT) were also investigated to evaluate the adsorption mechanism. At the same time, the static desorption and reusability of AB-COP were investigated. Finally, the dynamic enrichment effect of AB-COP for biflavonoids was investigated. The results showed that AB-COP was successfully synthesized by Fourier transform infrared spectroscopy (FT-IR), solid state nuclear magnetism (NMR), X-ray diffraction (XRD), thermogravimetric analysis (TG), scanning electron microscopy (SEM), laser particle size analysis and Brunner Emmet Teller (BET) specific surface area test. The optimized adsorption parameters of AB-COP were initial concentration of 0.5 mg/mL, temperature of 45 °C, solid-liquid ratio of 10:10 (mg/mL), adsorption time of 60 min. The Langmuir adsorption isotherm could effectively describe the adsorption process, the pseudo-secondary adsorption model could accurately explain the adsorption mechanism, and the DFT calculations revealed that the interaction forces of AB-COP and biflavonoids were π-π stacking and hydrogen bonding. In addition, AB-COP successfully resolved biflavonoids through urea-methanol (1.3 mol/L), and the material can be reused at least four times. Finally, the solid phase extraction (SPE) chromatographic column prepared by AB-COP was successfully applied to the enrichment of biflavonoids from S. doederleinii , and the effect was significantly better than traditional chromatography materials, andthis method was also successfully applied to the enrichment of flavonoids in other plant extracts including Flos sophorae, Pericarpium viride, Lophatheri herba, Herba cuscutae. These results provide references for further purification of bioactive ingredients from plant extracts by using AB-COP. [ABSTRACT FROM AUTHOR]

[Display omitted] • Uranium enrichment mainly occurs at the transition zone between Neogene and Quaternary sandstones. • The C-O isotopes of carbonates associated with U suggest involvement of hydrocarbons. • Disseminated uranyl silicates (coffinite) are major constituents of ore. There are several sandstone-type uraniferous basins around Tibetan Plateau. The Qaidam Basin is the largest sedimentary basin in the internal Tibetan Plateau, hosting important oil and coal resources, and has good potential for sandstone-hosted uranium resources. In this study, we examine the petrographic and mineralogical characteristics of a uranium mineralization interval at the Neogene-Quaternary transition (NQT) in the western Qaidam Basin using optical microscopy and electron probe microanalyzer (EPMA), including back scattered electron (BSE) imaging and energy-dispersive spectroscopy (EDS). The sedimentary lithofacies features and C-O stable isotopes of carbonate cement from two boreholes were analyzed, especially for the uraniferous interval. Whole-rock analyses of ores and barren rocks yielded highly variable U concentrations ranging from 1.5 to 2548 ppm. The main uranium minerals are coffinite and uraninite. The co-occurrence of uranium minerals with calcite indicates that uranium mineralization and calcite cementation were coeval. Coffinite mainly occurs at the interface between calcite cement and other minerals. The carbonates have δ13C V-PDB ranging from −29.67 to +3.93‰, suggesting involvement of organic carbon during uranium mineralization. This is also supported by the general trend of decreasing δ13C V-PDB and increasing U content from the conglomerate/coarse sandstone to the mudstone samples, and the overlap of δ13C V-PDB values between the calcite cement and organic matter in sedimentary rocks. The organic carbon may have been derived from hydrocarbons sourced from the deeper part of the basin and/or biogenic gases at shallow depths. The unconformity at the NQT may represent a favorable interval where oxidizing fluids carrying uranium met with reducing fluids carrying hydrocarbons and resulted in uranium mineralization. Thus, the NQT may serve as a guide for uranium exploration in this basin. [ABSTRACT FROM AUTHOR]

To study the degradation of directionally solidified turbine blades with different service times, four parts of four cross sections are selected to examine their microstructure through scanning electron microscopy. The width of the γ-phase channel, γ' volume fraction, types of carbides, and elemental composition are chosen to characterize the damage. Creep tests are carried out at four heights on the upper and lower parts of the turbine blades, and the residual creep life is determined. The degrees of degradation of the blades are examined based on the microstructures and creep test results of the samples with respect to various service times. The results indicate that the quantitative description of the microstructure is consistent with the experimentally obtained results for the remaining creep life. The relationships between the residual lives of the small samples and the width of the γ-channel and γ'-phase volume fraction are presented in a three-dimensional graph. Based on the creep damage model, a method for predicting the remaining life of the turbine blades in service is established. The predicted results of the remaining life fit well with the model results. • The study of serviced turbine blades can obtain first-hand information. • The volume fraction and size of the γ' phase are closely related to the mechanical properties. • The degradation degree of the same part of the blades increases with the large increase of service time. • There is a good correlation between the mechanical properties and the icrostructural features of the blades. • The quantitative description of the microstructure is consistent with the test results of the remaining creep life. • Based on the creep damage model, a method for predicting the remaining lives of turbine blades in service was established. [ABSTRACT FROM AUTHOR]

Megacrystalline uraninite (up to one centimeter in size) represents one of the most important discoveries in uranium mineralogy in the western margin of the Yangtze Block and even in China in recent years. However, the genesis of megacrystalline uraninite remains controversial. In this study, the megacrystalline uraninite found in the felsic and quartz veins in the Haita area is examined for the first time. The study examined the geochemical characteristics of uraninite in the two veins and resulted in two primary findings. (1) The genesis of the uraninite was likely intrusive and was closely related to partial melting. (2) The quartz vein and feldspar vein are cogenetic and have a simple differentiation evolution relationship. Therefore, the partial melting of felsic materials during migmatization may be the most important mechanism of uranium mineralization in the study area. Furthermore, further simple fractional crystallization may be another important mechanism for the formation of megacrystalline uraninite. This study enriches the REE database of uraninite in uranium deposits worldwide, which is meaningful for studying the genesis of megacrystalline uraninite. [ABSTRACT FROM AUTHOR]

An eco-environmental geochemical investigation was carried out in and around the Dexing mining area to determine the concentrations of heavy metals in the surface water, sediments, soils and plants. The main objective of this study is to assess the environmental situation and evaluate the transferring of heavy metals from mining activities into the food chain. Some samples of water, sediment, topsoil and plant were collected along the Lean River in the Dexing mining area. The total concentrations of Cu, Pb, Zn, Cd, and As were determined by AAS, and Hg was analyzed by cold-vapor AAS. Some indices such as 'contamination degree', 'geo-accumulation index', and 'biological absorption coefficient' were used to assess eco-environmental quality. The investigation indicated a highly localized distribution pattern closely associated with the two pollution sources along the Le'an River bank: one is strong acidity and a large amount of Cu in the drainage from the Dexing Cu mining area; and the other is the high concentrations of Pb and Zn in the effluents released from many smelters and mining, processing and extracting activities in the riparian zone. Results from the investigated localities indicated, at least in part, that some problems associated with environmental quality deterioration should be solved in the future. [ABSTRACT FROM AUTHOR]

Mining and smelting activities are the main causes for the increasing pollution of heavy metals in soil, water body and stream sediment. An environmental geochemical investigation was carried out in and around the Panzhihua mining and smelting area to determine the extent of chemical contamination in soil and sediment. The main objective of this study was to investigate the environmental geochemistry of Ti, V, Cr, Mn, Cu, Pb, Zn and As in soil and sediment and to assess the degree of pollution in the study are. The data of heavy metal concentrations reveal that soils and sediments in the area have been slightly contaminated. Geochemical maps of I[subgeo] of each heavy metal show that the contaminated sites are located in V-Ti-magnetite sloping and smelting, gangues dam. The pollution sources of the selected elements come mainly from dusts resultant from mining activities and other three-waste-effluents. The are needs to be monitored regularly for trace metal, especially heavy metal enrichment. [ABSTRACT FROM AUTHOR]

Presents a study that determined geochemical baseline models and assessed the contributions of trace elements from natural and anthropogenic sources in the Panzhihua mining area in China. Background on Panzhihua; Adoption of a normalization procedure to establish geochemical baselines; Analytical results and relevant parameters for trace metals in topsoil samples from the area.

• A label-free impedance sensor for cancer cells detection was developed. • Capture of cells on electrode surface based on hyaluronic acid-CD44 interaction. • The change of electron-transfer resistance was used to analyze CD44 expression. • CD44 expression on MDA-MB-231 cells is higher than that on L02 or HCT116 cells. In this study, a novel label-free electrochemical impedance spectroscopy (EIS) sensor was developed by successfully conjugating hyaluronic acid (HA) with bovine serum albumin (BSA)-modified gold nanoparticles (GNPs) for cancer cell quantification and CD44 expression analysis. Based on the molecular recognition of HA, the CD44-overexpressing cancer cells can be captured on the nanocomposites (HA-BSA-GNPs) modified electrode, increasing the electron-transfer resistance (R et). The change of R et was measured by the EIS to quantify the number of cancer cells and evaluate the CD44 expression level on the cell surface. Under optimal conditions, the change of R et was proportional to the logarithm of the cell concentration, namely from 2.0 × 102 to 3.0 × 105 cells mL−1 with a detection limit of 128 cells mL−1 for the MDA-MB-231 cells. Moreover, compared to HCT116 and L02 cells, the MDA-MB-231 cells exhibited a distinctly higher expression level of CD44. This indicates that the MDA-MB-231 cells have greater metastatic potential. The proposed sensor may find potential applications in cancer monitoring and research on tumor metastasis. [ABSTRACT FROM AUTHOR]

A series of visible-light-driven 3D TiO 2 -HNCs with 2D rGO heterojunction hybrids with facet-dependent contacts have been fabricated by a facile one-step solid-state calcination treatment via a topotactic transformation process with TiOF 2 as template for the first time. The unique facet-dependent contacting rGO with {1 0 1} instead of {0 0 1} facets of TiO 2 -HNCs hybrids facilitated the injection and transfers of photo-generated electrons from {1 0 1} facet of TiO 2 -HNCs to rGO and improved the photocatalytic degradation RhB rate constants under simulated sunlight irradiation. • A facile one-step solid state topological calcination strategy. • 3D anatase TiO 2 -HNCs illustrate mainly contact rGO via {1 0 1} facets. • TiO 2 -HNCs/rGO hybrids can enhance adsorption RhB abilities. • 3D/2D heterojunctions with intimate and large facet-dependent contact areas. One-step solid state calcination strategy via a template-engaged topotactic transformation process has been developed to construct serials of 3D TiO 2 hollow nanocubes (TiO 2 -HNCs) with 2D reduced graphene oxide (rGO) heterojunction hybrids with facet-dependent contact for the first time. The effect of calcination temperature and TiOF 2 /GO mass ratio on the morphology and photocatalytic activity of TiO 2 -HNCs/rGO hybrids was systematically discussed. The study indicated that 3D TiO 2 hollow nanocubes were assembled by six regular nanosheets and GO can effectively reduce the solid-state calcination temperature and facilitate the topological transformation from cubic TiOF 2 to TiO 2 -HNCs through 3D/2D heterojunctions hybridized to TiO 2 -HNCs, which also provided a transferring photo-induced electrons bridge to sensitize TiO 2 -HNCs for enhancing visible light response. The infrared spectra (IR), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopic studies revealed that rGO principally hybridized on the surface as sp2 graphitic carbon in extended p -π conjugated environments and a small percentage of rGO created carbonate structure by substituted surface Ti atoms in the TiO 2 -HNCs lattice. Due to the superior sensitization and charge carrier mobility of rGO, the photodegradation activity of Rhodamine B (RhB) of as-prepared T300/5rGO hybrid improved 4.6 times compared to P25 with a degradation yield of 99% within 90 min under simulated sunlight irradiation (>420 nm) and still remained over 95% after 5 recycles. The enhanced photoreactivity of TiO 2 -HNCs/rGO was mainly attributed to the strong hybridized interaction through chemical bonds between TiO 2 -HNCs and rGO, which formed 3D/2D facet-dependent contact heterojunctions and further verified by its good dispersibility and stability. The unique facet-dependent contacting rGO with {1 0 1} instead of {0 0 1} facets of TiO 2 -HNCs facilitated the injection and transfers of photo-induced electrons from {1 0 1} facet of TiO 2 -HNCs to rGO, thus retarding the recombination of electron-hole pairs, which was not only increasing the numbers of active sites, but also facilitating the adsorption of dye molecules, and improving light-harvesting ability, thereby enhancing visible photoreactivity of TiO 2 -HNCs/rGO hybrids. [ABSTRACT FROM AUTHOR]