Laser Raman Spectroscopy Research Articles

Mineralogical Characteristics and Color Origin of Nephrite Containing Pink Minerals

Recently, a variety of nephrite containing localized pink mineral aggregates has emerged on the market, which is sometimes referred to as “peach blossom jade” by some merchants. Currently, there is limited research on this type of nephrite containing pink minerals, and its detailed mineral composition characteristics and coloration mechanisms remain unclear. In this study, four samples of nephrite containing pink minerals were systematically investigated using conventional gemological tests, as well as modern analytical techniques such as X-ray powder diffraction (XRD), infrared spectroscopy (IR), laser Raman spectroscopy, ultraviolet–visible (UV-Vis) absorption spectroscopy, electron probe microanalysis (EPMA), and X-ray fluorescence spectroscopy (XRF). These techniques were employed to elucidate the mineral composition, chemical composition, spectroscopic features, and coloration origins of the samples. The results indicate that the primary mineral constituent of the samples is tremolite, with accessory minerals including zoisite, muscovite, orthoclase, andesine, diopside, and prehnite. The major chemical components of the samples are SiO2, CaO, and MgO, along with minor amounts of Al2O3, K2O, and FeOT. The overall green hue of the samples is positively correlated with Fe content. The pink mineral present in the samples is predominantly Mn-bearing zoisite, and the pink coloration of zoisite is primarily attributed to the energy level transitions of Mn2+ at approximately 540 nm and 440 nm.

Insights into the High Activity of Hydrotreating Catalysts for Heavy Gas Oil

The objective of this work was to develop a highly active hydrotreating catalyst for processing heavy gas oil to provide qualified feedstock for hydroisomerization or a hydrocracking unit. The NiMo/γ-Al2O3 catalysts doped with phosphate were prepared by introducing two kinds of additives, and the influencing factors for highly active hydrodenitrogenation (HDN) were revealed. TEM analysis results showed that the catalyst with a small MoS2 stack length tended to have high activity due to more active sites being exposed. Laser Raman spectroscopy demonstrated that the catalysts contained PMo12O403− metal active phases. For industrial heavy VGO feedstock, the nitrogen content can be reduced to 2 ppm with a hydrotreating process. The VI of the hydrotreated product can be improved from 132 to 145 after hydrotreatment, which is necessary to produce group III base oil as the most valuable base oil type. This work provides an insight into the high activity of hydrotreating catalysts for industrial lubricant hydroprocessing.

Microwave-Assisted Reduction of Graphene Oxide to Reduced Graphene Oxide

Green chemistry seeks to find alternative synthesis routes that are less harsh to living organisms and the environment. In this communication, a microwave-assisted hydrothermal technique and a thermal annealing method were used in the reduction of graphene oxide (GO) to make reduced GO (rGO). Graphite powder was oxidised using the Improved Hummers’ method, exfoliated, and freeze-dried. Thereafter, an aqueous suspension of GO was reduced under microwave (MW) irradiation for 10 min at 600 W with and without the help of a reducing agent (hydrazine hydrate). Thermal annealing reduction was also conducted under a nitrogen atmosphere at 300 °C for 1 h. Prepared samples were analysed using Raman laser spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), the Brunauer–Emmett–Teller (BET) method, and X-ray photoelectron spectroscopy (XPS). A successful reduction in the GO functional groups between the sheets was established using XRD. In the Raman analysis, the ratio of the intensity of the D and G band (ID/IG) in graphene sheets assisted in assessing the quality of the graphene films. An estimation of the number of structural defects was calculated using the ID/IG ratio. The Raman analysis showed an increase in the ID/IG ratio after both oxidation and reduction processes. The defect densities of both MW-treated samples were comparable while an increased defect density was evident in the thermally annealed sample. TEM micrographs confirmed the sheet-like morphology of the samples. The rGO sheets obtained from the MW-treated method appeared to be smaller when compared to the rGO ones obtained by thermal treatment. It was also evident from XRD analysis that thermal treatment promoted the coalition of graphitic layers, such that the estimated number of layers was larger than that of GO. The elemental analysis showed that the C/O ratio of GO increased from 2 to 7.8 after MW hydrazine reduction.

Raman spectroscopy of dried serum for the detection of rapid noninvasive multiple myeloma

Raman spectroscopy has recently emerged as an attractive focus of research interest in studies of hematological diseases. However, comprehensive Raman spectral analyses of serum samples from patients with multiple myeloma (MM) or other forms of lymphatic neoplastic disease are lacking. In this study, laser Raman spectroscopy and orthogonal partial least-squares discrimination analysis (OPLS-DA) were employed to develop a simple, noninvasive approach to MM diagnosis based on dried serum samples. To that end, systematic OPLS-DA analyses of dried serum from 35 patients with MM and 13 healthy controls were performed, revealing clear differences between these two groups in terms of the resultant serum spectral data. Specifically, significant reductions in the intensities of Raman peaks corresponding to nucleic acids (726, 781, 1579 cm−1), proteins (621, 1603, 1616 cm−1), lipids (1437, 1443, 1446 cm−1) and carotenoids (957, 1160, 1520 cm−1) were observed in MM, together with increases in the intensities of peaks corresponding to carbohydrates (920, 1123 cm−1) and collagen (1345 cm−1). Through combined analyses of serological indices associated with metabolic activity, MM patients were confirmed to exhibit elevated serum glucose levels and decreased levels of high-density lipoprotein cholesterol. These results offer a spectroscopic foundation for the relationships between MM classification and serological testing data, offering new evidence that can guide the early and efficient identification and characterization of this deadly cancer type. This exploratory study thus offers insight into the potential utility of Raman spectroscopy as a tool for the noninvasive detection of specific subtypes of MM.

Optimizing laser-induced phase transformations in Sb2S3 thin films: Simulation framework and experiments

We present a novel simulation approach combined with pulsed laser experiments, spectroscopic ellipsometry, and Raman spectroscopy to comprehensively analyze phase transformation dynamics in thin films. The simulations apply to any thin film stack and incorporate critical factors, such as thin film interference, heat transfer, and temperature-dependent optical properties during heating and melting. As a case study, we investigate the picosecond laser-induced amorphization of antimony sulfide (Sb2S3) thin films, a promising alternative to traditional phase-change materials in photonic applications to validate the simulation model. The computational efficiency of our simulations enables not only the investigation of the laser-induced phase transformation but also the optimization of key process parameters and parameter fitting. The simulations identified optimal film thickness and laser fluence parameters that maximize energy efficiency, melting effectiveness, and quenching rate while ensuring high reflectivity contrast between the amorphous and crystalline states. By constructing a wide-ranging, high-resolution parameter map of the laser fluence and film thickness dependence of the melting process, we demonstrate how this model guides the understanding of phase transformation dynamics. Raman spectroscopy confirms the polycrystalline to amorphous transition of Sb2S3 and provides a semiquantitative estimate of the amorphous fraction as a function of laser fluence, which is qualitatively consistent with the simulation predictions of the model. The open-source simulation framework, experimentally validated, provides valuable insights into laser-induced amorphization dynamics in Sb2S3 and related phase-change material thin films, enabling rapid optimization of photonic devices.

Synthesis of low‐cost microporous activated carbon adsorbents for CO2 capture from Palmyra palm fruit shell waste biomass

AbstractUsing chemical activation techniques at dissimilar carbonization temperatures, activated carbon adsorbents were produced from Palmyra palm fruit biomass in this work. X‐ray diffraction, Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, laser Raman spectroscopy, scanning electron microscopy, CHNS‐elemental analysis, and N2 adsorption studies were among the characterization techniques used to assess the characteristics of the carbon adsorbents. The carbon adsorbents from Palmyra palm fruit were used to absorb CO2 in a temperature range of 25–70°C. The findings of the characterization showed that these carbons have a large surface area and microporosity. The temperature of carbonization and the activating agent had an impact on the surface characteristics. The samples with the highest adsorption capacity, 4.70 mmol/g at 25°C, were the activated carbons made by treating them with KOH and then carbonizing them at 750°C. The physicochemical properties of the adsorbents provided an explanation for their high adsorption capacity. The adsorbents showed simple desorption and maintained constant activity during ten cycles of recycling.

Mechanical properties of shale during pyrolysis: Atomic force microscopy and nano-indentation study

Quantitative characterization of the geo-mechanical properties of shale and organic matter (OM) holds paramount significance in the assessment of shale gas reserves and the design of hydraulic fracturing. However, the mechanical evolution processes during shale hydrocarbon generation and its influencing factors have received limited attention. This study examines the changes in shale mechanical properties during pyrolysis at high temperatures (415–600 °C) and high pressure (50–125 MPa) for mature to over-mature stages. The nanoindentation and in-situ AFM-QNM analysis are utilized to characterize the changes in mechanical properties during evolution. Subsequently, gas adsorption, Fourier Transform infrared spectroscopy (FTIR), and laser Raman spectroscopy (Raman) are used to investigate the factors influencing the mechanical properties of shale and the associated OM, and establish a model for the evolution of the mechanical properties. The results demonstrate that with increasing maturity, the overall Young's modulus of the bulk shale gradually increases from 42.8 GPa to 58.4 GPa for the temperature increment from 415 °C to 600 °C. During the thermal maturation process, the mesopore structure and quartz content of the shale significantly influence its mechanical properties. Young's modulus of OM shows an S-shaped trend, with variations in the micromechanical properties of OM corresponding to stages of hydrocarbon generation. In particular, two peaks of Young's modulus increase are observed during the mature and over-mature stages. In the mature stage, the aromatization of the kerogen leads to substantial detachment of aliphatic side chains and oxygenated functional groups, resulting in a higher degree of aromatization. This reduces the kerogen spacing and consequently increases the Young's modulus. In the over-matured stage, the process of aromatics condensation leads to the orientation and arrangement of aromatic rings, reducing the number of key site vacancies and crystal defects, thereby forming large aromatic clusters and significantly increasing the graphite-like structure. This study will facilitate the analysis of shale matrix deformation mechanisms at the microscale, providing a fundamental theoretical and scientific basis for shale fracturing design, exploration, and development.

The Contribution of Carbonaceous Material to Gold Mineralization in the Huangjindong Deposit, Central Jiangnan Orogen, China

The Huangjindong gold deposit in northeastern Hunan is one of the most representative gold deposits in the Jiangnan Orogenic Belt. The orebodies are mainly hosted in the Neoproterozoic Lengjiaxi Group, which comprises carbonaceous slates. Abundant carbonaceous material (CM) can be found in the host rocks and ore-bearing quartz veins, but its geological characteristics and genesis, as well as its association with gold mineralization, are still unclear. Systematic petrographic observation demonstrated two types of CM in host rocks and ores, i.e., CM1 and CM2. Among them, CM1 is the predominant type and mainly occurs in the layered carbonaceous slates, while CM2 is mostly present in quartz veins and mineralized host rocks. Laser Raman spectroscopic analyses of CM1 were performed at higher temperatures (376–504 °C), and CM2 was generated at similar temperatures (255–435 °C) to gold mineralization. Combined with previous studies, we can conclude that CM1 was produced by Neoproterozoic to early Paleozoic metamorphism before gold mineralization, while CM2 is of hydrothermal origin. Geochemical modeling indicates that CM1 could promote gold precipitation through reduction, as well as facilitate structure deformation and metal absorption as previously proposed. However, hydrothermal CM2 is favorable for gold mineralization because it triggers sulfidation, similar to other Fe-bearing minerals (such as siderite) in the host rocks. Consequently, both types of CM in the Huangjindong deposit are favorable for gold mineralization and carbonaceous slates could be important gold-bearing units for future ore prospecting in the Jiangnan Orogen as well as other places in South China.

Hydrocarbon charge history of deeply buried clastic reservoirs in the Bozi area of the Kuqa Depression, western China: implications for deep and ultra-deep petroleum exploration

Significant progress has recently been made in deep and ultra-deep oil and gas exploration globally, demonstrating enormous exploration potential of the deep and ultra-deep strata. However, the accumulation and preservation pattern of deep and ultra-deep oil and gas remains poorly understood, greatly impeding further petroleum exploration and development in the deep and ultra-deep strata. By taking the Bozi deep and ultra-deep condensate gas reservoirs in the Kuqa Depression, western China as an example, we attempt to reconstruct the hydrocarbon charge history in such deep reservoirs via an integrated investigation involving quantitative grain fluorescence, fluid inclusion petrography and microthermometry, micro-fluorescence spectroscopy, laser Raman spectroscopy, PVTx modelling, and basin modelling. The results show that: (1) The Bozi deep and ultra-deep reservoirs contain one group of gas inclusion assemblage, and two groups of oil inclusion assemblages, with one being characterized by near yellowish-whitish and blue-whitish diphasic or triphasic oil inclusions, and the other being featured by bright blue diphasic oil inclusions; (2) The first oil charge occurred during the Early Neogene (6.5–5.5 Ma), and the second oil charge occurred during the Late Neogene (4.4–3.5 Ma), under normal hydrostatic pressure or slightly weak overpressure; and (3) The gas charge occurred during the Pleistocene (∼1.6 Ma), with a corresponding reservoir pressure coefficient of approximately 1.7, transforming the reservoir fluid phase state from black oil or volatile oil to condensate gas. Our findings highlight that aside from the present burial depth, a favorable burial history model is crucial for the preservation of liquid hydrocarbons in deep and ultra-deep reservoirs. The occurrence of liquid hydrocarbons in the Bozi deep and ultra-deep condensate gas reservoirs with depths over 7,000 m is benefited from a prolonged period (>100 Ma) of shallow burial and a late-stage (since 10 Ma) rapid subsidence.

Fluid evolution and genesis of the Shipenggou gold deposit in Central Jilin Province, China: Constraints from C–H–O and in–situ sulphur isotopes of pyrite and fluid inclusions

The origin and evolution of the Shipenggou gold deposit in the Shipenggou–Jiapigou–Jinchengdong (SJJ) gold belt in Jilin Province, Northeast China, remain poorly understood. In this study, fluid inclusion and C–H–O–S isotopes from the Shipenggou deposit were investigated to clarify the fluid evolution and mineralisation process. The gold mineralisation is hosted in the biotite plagiogneiss of the Archaean Sandaogou Formation and is dominated by gold–bearing quartz veins. The orebodies are controlled by NNE– and NEE–striking brittle–ductile structures. Four stages of mineralisation have been identified: (I) milky quartz–minor pyrite, (II) quartz–pyrite–minor gold, (III) gold–quartz–polymetallic sulphide, and (IV) quartz–carbonate. Fluid inclusions were identified as four types: aqueous (VL–type), CO2–bearing (CL–type), CO2–rich (LC–type), and carbonic (PC–type). VL–, CL–, LC–, and PC–type FIs were developed within quartz from Stages I–II. Stage III quartz contains both CL– and VL–type FIs. Only VL–type FIs were observed in calcite from Stage IV. The total homogenisation temperatures (Tht) of FIs in Stages I, II, III, and IV are of 281.5–324.8, 215.5–269.1, 151.2–198.3, and 125.4–149.5 °C with salinities of 2.8–13.2, 2.8–9.6, 3.2–8.4, and 3.0–5.9 wt% NaCl eqv. Laser Raman spectroscopy analysis indicated the CL– and PC–type FIs from Stages I and II contain CO2 and minor quantities of CH4. The ore–forming fluids have developed from a medium temperature, low–medium salinity immiscible NaCl–H2O–CO2 ± CH4 system to a low temperature, low salinity homogeneous NaCl–H2O system. The HO isotopic compositions indicate that the initial ore–forming fluids were mantle–derived magmatic water. Subsequently, the ore–forming fluids were gradually joined by meteoric water. δ13C values indicate C in the fluids have originated from organic matter. Organic matter may have originated from the mantle, which mixed crust materials influenced by the subduction of the Palaeo–Pacific slab. In–situ, S isotope data of pyrite indicate that the origin of sulphur at the Shipenggou deposit is the mantle containing a crust component. Based on the above analysis results, the Shipenggou gold deposit is a mesothermal magma-hydrothermal vein–type gold deposit.

Contrasting fracturing and cementation timings during shale gas accumulation and preservation: An example from the Wufeng-Longmaxi shales in the Fuling shale gas field, Sichuan Basin, China

The marine shales in southern China are characterized by high thermal evolution and intensive deformation during multistage burial and uplift. Fracturing and cementation, associated with tectonic activity, diagenesis, hydrocarbon generation and migration processes, are widely and variably distributed in shale reservoirs experiencing different tectonic evolution. In this study, we utilized cross-cutting relationships, fluid inclusion microthermometry, and laser Raman spectroscopy of fluid inclusions, along with U-Pb dating of fracture-filling calcite veins, integrated with burial history modeling, to elucidate the timing and mechanism of fracturing in the Paleozoic Wufeng-Longmaxi shale reservoir, as well as regional variations in the Fuling shale gas field. Bedding-parallel fractures (BFs) in shale reservoirs are filled with calcite and quartz veins. The timing of fracturing, as determined by minimum homogenization temperatures and U-Pb dating, is estimated to have occurred during ca. 191 -122 Ma, during which some short vertical (or high-angle) fractures (VFs) opened around 163.4 Ma and 137 Ma, subsequently sealed by calcite veins, respectively. All calcite and quartz veins within these fractures contain high-density methane inclusions, while shale reservoirs were in a high-over-mature evolutionary stage. This suggests that fracturing was primarily driven by gas generation overpressure during deep burial. In shale reservoirs near fault belt folds, multistage fractures developed, including three stages of intersecting fractures (IFs) and one-stage of long VFs. The timing of fracturing and cementation corresponds to the Yanshanian tectonic uplift (ca. 83 - 69 Ma) with intense tectonic movement likely being the direct cause of fracture opening. The presence of abundant gas inclusions in veins recorded shale gas expulsion during rapid tectonic uplift, reflecting the destruction of shale gas preservation conditions. In contrast, no significant fracturing or cementation processes have been observed in the tectonically gentle zones. The different fracturing and cementation processes indicated that preservation conditions declined with increased fracture openings during uplift, correlating with the gas enrichment.

Maturity characterization and formation mechanisms of nano-scale anisotropic pyrobitumen based on atomic force microscopy (AFM)

Highly evolved pyrobitumen is an important and realistic object for maturity characterization of ancient and deeply buried organic matter, but measurement of its reflectance is challenging due to its strong optical anisotropy and nano-scale relief. Here we conducted a case study in the Sinian (Ediacaran) Dengying Formation of the Sichuan Basin, China. High-resolution, three-dimensional, morphological imaging by atomic force microscopy (AFM), laser Raman (LRM) spectroscopy, and reflectance studies were conducted on the reservoir pyrobitumen. Our results show that Young’s modulus and adhesion, which are mechanical maturity parameter, provides effective characterization of maturity. The increase in Young’s modulus of pyrobitumen lags that of the vitrinite, given that pyrobitumen is formed by oil cracking and is more hydrogen-rich than vitrinite. A quantitative relationship between Young’s modulus, adhesion and reflectance in bright and dark areas of pyrobitumen was established, which can be used for maturity characterization. The changes in Young’s modulus of the pyrobitumen is related to the condensation of organic matter and directional arrangement of microcrystals. Young’s modulus of organic matter is a robust mechanical maturity index at high organic matter maturity (Ro > 2.0 %), but it is important to pay attention to the influence of anisotropy. Compared to Young’s modulus, adhesion is less affected by anisotropy. The nano-mechanics such as Young’s modulus and adhesion will be new maturity indicator in addition to conventional optical and spectroscopic method. The nano-mechanical properties of organic matter are expected to be applied to maturity indicators and macerals classification in the field of organic petrology in the further research.

Phytosynthesis of titanium dioxide nanoparticles using Cynodon dactylon leaf extract and their antibacterial activity

Due to use of nanoparticles, nanotechnology has become an important area of research penetrating in all the fields of science and technology including medicinal chemistry. Titanium dioxide nanoparticles (TiO2 NPs) play an important role in biotechnology and nanomedicine because of their antimicrobial effect against many pathogens such as bacteria, fungus, viruses and yeast. In this article, we propose an eco-friendly phytosynthesis method of TiO2 NPs using aqueous leaf extract of Cynodon dactylon herbal plant as a reducing agent. The formation of TiO2 NPs by plant bio-molecules involved in the reduction of metal ions to nanoparticles is demonstrated. The synthesized TiO2 NPs are analyzed using X-ray diffraction analysis, Fourier transform infrared spectroscopy, laser Raman spectroscopy and field emission scanning electron microscopy. The antibacterial activity of the TiO2 NPs against gram-positive bacterial pathogens like Bacillus subtilis and Staphylococcus aureus as well as gram-negative bacterial pathogen like Escherchia coli is tested. The obtained results demonstrate potent bactericidal activity of the TiO2 NPs.

Interfacial properties and mechanical performance of hybrid graphene/carbon fibre composites

The interaction zone between the matrix and the reinforcing component within carbon fibre (CF) composites plays a crucial role in influencing their performance characteristics, as extensively documented in scientific literature. Building on this fundamental knowledge, this research focuses to the investigation of the interface of fibrous composites and the effect of the incorporation of graphene nanoplatelets (GNPs) into the epoxy matrix. Through the utilization of laser Raman spectroscopy, a significant increase of over 60 % in interfacial strength with just a 2 % weight fraction of GNPs, as expressed by the enhanced shear-lag parameter observed in single fibre model composites, has been observed on model composites indicating a stronger interfacial interaction between the matrix and fibres. The effect of the incorporation of GNPs on CF-graphene interaction has been also investigated on a macroscopic level. Hybrid carbon fibre epoxy resin composite produced, by the introduction of GNPs into the polymer matrix. A series of mechanical tests were conducted, including extensive tensile testing of epoxy/graphene nanocomposite films, thorough examination of bending characteristics, and meticulous measurement of interlaminar shear strength for hybrid GNP/carbon fibre composites. These evaluations provided a clearer understanding of how the GNP integration affects the interface parameters that govern the mechanical behaviour of both the resin and carbon fibre composites.

Fast fabrication of superhydrophobic Ti-6Al-4V surface using Q-switched nanosecond pulsed laser at 1064 nm and cyclohexane

Superhydrophobic and superhydrophilic surfaces are attracting significant attention in fundamental and applied research. This study fabricated the micro/nanostructure with a Q-switched nanosecond pulsed laser on the Ti-6Al-4V surface. Three laser-generated surface topographies on titanium were produced based on three different pitch sizes (51 μm, 34 μm, and 29 μm). The laser textured surfaces (LTS) were studied in terms of both structure evolution and chemical composition using Field Emission Scanning Electron Microscopy (FE-SEM), Optical Microscopy (OM), Confocal Laser Scanning Microscopy (CLSM), Raman Spectroscopy, and X-ray Diffractometer (XRD). 29 μm pitch displayed the lowest water contact angle of 18.5° and surface roughness of 0.5 μm. This structure was further treated with cyclohexane at different temperatures. The best sample reached superhydrophobicity with a maximum water contact angle of 155.1° immediately after being treated with cyclohexane at the low temperature of 70 °C for 2 h, while the raw surface, for comparison, showed no change in hydrophobicity after being treated with cyclohexane under the same condition. Thus showing clear evidence of a combined effect between LTS and post-treatment. The surface features were assessed to explain the underlying process.

Research on the mechanism of natural antibacterial properties of Calotropis gigantea fiber

This research explores the antibacterial mechanism of Calotropis gigantea (CG) fiber through systematic antimicrobial testing and microstructural characterizations on different types of dried CG fibers. Different temperatures and light exposure times were employed to prepare a series of fiber samples. Standard antimicrobial tests were conducted, revealing that both light exposure time and drying temperature significantly influenced the fiber's antibacterial properties against Escherichia coli. Prolonged light exposure time and drying temperatures notably suppressed the antibacterial efficacy. Chemical composition, surface morphology, and thermal stability were further investigated using various techniques, including laser microscopy, Raman, FTIR, and X-ray photoelectron spectroscopies, as well as thermogravimetric-differential thermal analysis. The results revealed a minor role of surface profile and lignin in the variation of antibacterial properties of CG fiber, which should mainly be associated with the alteration of flavonoids, despite the presence of distinct mass losses and decomposition temperature shifts after fiber drying. This study not only unveils and confirms the resource and mechanism of the antimicrobial activity of Calotropis gigantea fiber but also provides insights to guide future optimization of processes and control of microstructure. These findings hold promise for the development of Calotropis gigantea fiber applications in antibacterial products.

New Evidences of Fluid Inclusions from Wufeng Formation Reveal Shale Gas Accumulation and Leakage Histories in Northern Guizhou, Southwestern China

Abstract Shale gas accumulation and leakage histories are significant for evaluating the prospects of hydrocarbon exploration. The Wufeng Formation in northern Guizhou is a potential target for shale gas exploration and development. This work selected a typical Well YH1 to conduct detailed fluid inclusion analyses in the Wufeng Formation. We integrated the inclusion results with systematic core description, thin-section microscopic observation, laser Raman spectroscopy, microscopic temperature measurement, and burial–thermal history to reveal shale gas accumulation and leakage histories in northern Guizhou. The results show that the source rocks of the Wufeng Formation occurred in oil generation since the Permian and entered the stage of natural gas generation at the end of the Late Triassic. During the Early Jurassic and Early Cretaceous, shale gas accumulated in the Wufeng Formation reservoirs, and the stratigraphical pressure coefficient ranged from 1.47 to 1.97. Under the influence of the Yanshan orogeny, northern Guizhou experienced a rapid uplift and exhumation since the end of the Early Cretaceous. Under the influence of this tectonic, the stratigraphical pressure plummeted to the normal level, adversely impacting the accumulated shale gas in reservoirs and resulting in leakage events since the end of the Early Cretaceous. The reservoirs were further destroyed and adjusted, and the gas continued to leak because of a long-term and large-scale uplift and exhumation during the Himalayan orogeny. This work clarified that shale gas accumulation and leakage histories are significant for evaluating petroleum exploration.

Enhanced growth rates of N-type phosphorus-doped polycrystalline diamond via in-liquid microwave plasma CVD

Phosphorus-doped diamond (PDD) exhibits excellent properties, making it suitable for a wide range of applications, such as electronic devices and electrodes. Here, we report the first synthesis of PDD by in-liquid microwave plasma CVD (IL-MPCVD) under high-pressure and low-power conditions. A mixture of methanol (MeOH) and ethanol (EtOH) with triethyl phosphate ((C2H5)3PO4) and (P/C = 1000 ppm) was used for the PDD deposition. Samples were characterized by laser microscopy, Raman spectroscopy, and glow discharge optical emission spectroscopy. Notably, PDD was successfully produced at a growth rate of 280 μm/h, which is two orders of magnitude higher than conventional CVD methods. Additionally, cyclic voltammetry (CV) and impedance spectroscopy (EIS) were used to evaluate the electrochemical properties of PDD. As a result, we confirmed the wide potential window characteristic of conductive diamond and determined that the donor density was [P] = 3.8 × 1017cm⁻³. Therefore, it is clear that IL-MPCVD is applicable for very high growth rates in the CVD process for PDD synthesis.

Genesis of the Jianbeigou Gold Deposit on the Southern Margin of the North China Craton: Insights from Fluid Inclusions, H‐O‐S Isotopes, and Pyrite in situ Trace Element Analyses

AbstractThe Jianbeigou gold deposit is a typical lode gold deposit in the Qinling metallogenic belt, located on the southern margin of the North China Craton. Three stages of the hydrothermal process can be distinguished, including the quartz ± pyrite, quartz‐polymetallic sulfide, and quartz‐carbonate ± pyrite stages. From the early to late stages, the homogenization temperatures of primary fluid inclusions are 281–362°C, 227–331°C, and 149–261°C, respectively. The corresponding salinities estimated for these fluids are 3.9–9.9 wt%, 0.4–9.4 wt%, and 0.7–7.2 wt% NaCl equiv. Combined with laser Raman spectroscopy data, the ore‐forming fluid belongs to a H2O‐CO2‐NaCl ± CH4 system with medium–low temperature and salinity. The δ18Ofluid and δD values for the quartz veins are –1.0‰ to 6.0‰ and –105‰ to –84‰, respectively, which indicates that the ore‐forming fluid is of mixed source, mainly derived from magma, with a contribution from meteoric water. Pyrite has been identified into three generations based on mineral paragenetic sequencing, including Py1, Py2, and Py3. The pyrites have δ34S sulfur isotopic compositions from three stages between 3.7‰ and 8.4‰, indicating that sulfur mainly originated from magma. Te, Bi, Sb, and Cu contents in pyrite were all high and showed a strong correlation with Au concentrations. Native gold and the Au‐Ag‐Bi telluride minerals were formed concurrently, and the As concentration was low and decoupled from the Au content. Therefore, Te, Bi, Sb and other low‐melting point chalcophile elements play an important role for gold mineralization in arsenic‐deficient ore‐forming fluid. Combined with the geological setting, evolution of pyrite, and ore‐fluids geochemistry, we propose that the Jianbeigou deposit can be classified as a magmatic–hydrothermal lode gold deposit. Gold mineralization on the southern margin of the North China Craton is related to Early Cretaceous magmatism and formed in an extensional setting.

Na2.64Mn1.64(MoO4)3 and Na2.62Ni1.69(MoO4)3: Physicochemical investigations and electrochemical properties as 3.5 V class positive electrode material for Na-batteries

Powders of two new mixed molybdates Na2.64Mn1.64(MoO4)3 (1) and Na2.62Ni1.69(MoO4)3 (2) have been prepared via a solid-solid reaction. They are isostructural, both crystallizing in monoclinic system (S. G.: C2/c), Z = 1, and the unit cell parameters a = 12.74109 (18) Å, b = 13.69390 (15) Å, c = 7.20028 (8) Å, β = 112.4314 (7) °, V = 1161.22 (2) Å3 (1), and a = 12.6368 (2) Å, b = 13.3633 (2) Å, c = 7.08501 (10) Å, β = 111.9248 (10) °, V = 1109.91 (3) Å3 (2). The structure consists of a 3D network of corners and edges sharing [MoO4] and [MO6] polyhedral, delimiting tunnels in which the Na ions partly site. The samples were investigated by powder X-ray diffraction, infrared spectroscopy, and scanning electron microscopy coupled to energy-dispersive X-ray spectroscopy (SEM-EDX). The vibrational study confirms the existence of the MoO42− functional groups. Laser Raman spectroscopy showed that the MoO42− tetrahedra in the two compounds are more regular, suggesting high symmetry for the compound. The as-synthesized compounds are fiber-like grains with an average length of 10−1 μm. FT-IR spectra showed the presence of all the functional groups present in the compounds. Magnetisation measurements showed their paramagnetic behaviour. The title compounds were characterized by cyclic voltammetry (CV), electrochemical performance and limiting factors are also applied as electrode material for Na-ion batteries at room temperature. Benefiting from these advantages, between 1.5 V and 4.6 V, (1) and (2) deliver high specific capacities of 230 and 160 mA h g−1 after 60 cycles, and good rate performances, respectively. It can also be inferred that the prepared electrocatalyst showed for both phases excellent Hydrogen Evolution Reaction (HER) performance with an overpotential of 531 mV for Mn and 512 mV for Ni, required to afford a current density of 10 mA cm−2.