Search

Bulk chemical composition analysis is a primary and pivotal analytical task for extraterrestrial geological samples (e.g., lunar soil, asteroids, or meteoroids). However, the analysis of mg-level consumption of extraterrestrial geological samples poses a significant challenge to existing analytical techniques. In this study, a new method was developed for trace element determination in bulk extraterrestrial geological samples prepared as lithium borate glasses, following customized procedures for X-ray fluorescence (XRF) analysis with a 10 mg sample by femtosecond LA-ICP-MS. All thirty-two trace elements in the borate glass samples were evenly distributed with homogeneity indices (H) < Hcrit. For the borate glass samples, Si was more suitable as an internal standard for Co, Ni, Cu, and Zn, whereas Al was better for the others. The femtosecond laser greatly reduces the influence of matrix effects, making calibration with non-matrix-matched external standards (NIST 612 and 614) accurate. Although the mass ratio of the flux and sample was as high as 35 : 1, the analytical results of 32 trace elements in six silicate rock reference materials (covering mafic to felsic rock types) using the developed technique were consistent with the reference values within 10% for most elements, and analytical precision (RSD) was also within 10% for most elements. Finally, one lunar basalt (NWA14526) and one shergottite (NWA13190) were assayed using the proposed method, and a comparison with the results of solution nebulization (SN)-ICP-MS confirmed the reliability of the method. The proposed method, combined with XRF, achieved the rapid, simultaneous, and accurate determination of major and trace elements in the same small sample aliquot (10 mg), which is highly suitable for the analysis of extraterrestrial geological samples. [ABSTRACT FROM AUTHOR]

The article used sebacic acid and meta phenylenediamine as raw materials, and explored the synthesis process of nylon MXD10 through high-temperature and high-pressure melt polymerization. On this basis, the performance of the synthesized semi-aromatic nylon MXD10 was characterized. The structure of nylon MXD10 was analyzed using Fourier transform infrared spectroscopy. The thermal properties of nylon MXD10 were analyzed by differential scanning calorimetry and thermogravimetric analyzer. The results showed that the melting temperature and crystallization temperature of the synthesized nylon MXD10 were 175 °C and 117 °C, respectively. Thermal decomposition was a one-step decomposition method. Non isothermal crystallization kinetics analysis was also conducted on nylon MXD10, and the non isothermal crystallization kinetics of semi-aromatic nylon MXD10 were studied comprehensively through the Jeziorny equation and Mo Zhishen method. The results indicate that the crystal growth of semi-aromatic nylon MXD10 is two-dimensional, and the crystallization temperature decreases with the increase of cooling rate. The activation energy is -981.625 kJ/mol. [ABSTRACT FROM AUTHOR]

Objective: The Polygonatum cyrtonema was processed to investigated its effects on material and energy metabolism in CUMS depressed model mice. Methods: 80 KM/SPF mice were randomly divided into model group, positive group, processed P. cyrtonema group and compatible group, with male and female were equally divided. CUMS depressed mice model were established by unpredictable mild stress for 28 days. The levels of ICD, α-KGDHC, ATPs and Na+-K+ ATPase in brain, cerebellum, liver, kidney and spleen were detected by ELISA. Results: Processed P. cyrtonema and its compatibility had different effects on the enzyme levels of material and energy metabolism in both male and female mice. Compared to the positive group, each treatment group was affected significantly (P＜0.05). P. cyrtonema could significantly increase the α-KGDHC content in brain, cerebellum, liver, kidney and spleen of female mice (P＜0.01), and complex differences in levels of ICD α-KGDHC, ATPs and Na+-K+ ATPase in different organs of male and female mice were observed. Conclusion: Processed P. cyrtonema and its compatibility had different effects on the enzyme levels of marerial and energy metabolism in both male and female mice. P cyrtonema group had the strongest effect on depressed mice.

OBJECTIVES The Xiuwacu Mo-W deposit is a typical hydrothermal quartz vein deposit in the Yidun island arc Cu-Mo metallogenic belt, northwest Yunnan. Numerous studies have been conducted on rock and ore chronology and petrogenesis, dynamics, but its ore-forming fluid evolution has been rarely studied. OBJECTIVES To reveal the origin and evolution of ore-forming fluids of the Xiuwacu Mo-W deposit. METHODS Scanning electron microscope (SEM) cathodoluminescence method, and in situ trace element (LA-ICP-MS) and in situ Sr (fs-LA-MC-ICP-MS) isotope analyses of scheelite. RESULTS The occurrences of scheelite and the cathodoluminescence images indicated three generations of scheelite, Ⅰ, Ⅱ, and Ⅲ, with the middle stage scheelite being the most developed. The rare earth element pattern of the scheelite in the early stage was similar to that of the porphyritic granite. It showed a right-inclined pattern with light rare earth enrichment and a moderate negative Eu anomaly (δEu=0.42). The average Mo content was 3.0%, and the average 87Sr/86Sr was 0.7098, close to the specular feldspar granite (0.7075-0.7098). Compared with scheelite in the early stage, the content of light rare earth elements in the scheelite from the middle stage was low, and Eu also had a medium negative anomaly (δEu=0.37). Mo content was reduced to an average of 2445μg/g, and 87Sr/86Sr increased to 0.7113. The rare earth distribution pattern of scheelite in the later stage showed an arched pattern with relative enrichment of middle rare earth and no Eu anomaly (δEu=0.93). Mo content of scheelite decreased to 56μg/g, and average 87Sr/86Sr was 0.7083. Conclusion From early to late, the gradual decrease of light rare-earth elements, especially La and Ce, in scheelite indicates the crystallization of bastnaesite. The increase in δEu and the sharp decrease in Mo content indicate the transformation of ore-forming fluids from oxidation to reduction. The change of Sr isotope composition indicates the change in the source of ore-forming materials. The magmatic fluid contributed a lot in the early stage, and the large-scale interaction between the magma-hydrothermal fluids and surrounding rocks is responsible for the formation of scheelite in the middle stage. The strata provide amounts of Ca for scheelite formation, indicating that strong water-rock interaction played an important role in the formation of the deposit.

BACKGROUND The Nanyangtian scheelite deposit is an important skarn scheelite deposit in Yunnan Province, which is located in Laojunshan W-Sn deposit area, Southeast Yunnan. Due to its complex geological background and multi-stage metallogenic characteristics, its mineralization age and genesis remain controversial. OBJECTIVES To explore the metallogenic age, genesis and material origins of two types of scheelite deposits in order to explore formation patterns. METHODS Molybdenum Re-Os isotope dating was used to constrain the age, whereas in situ trace element and in situ Sr isotopes of scheelite were used to determine the composition of trace elements and Sr isotopes in scheelite. RESULTS The Re-Os isochron age of molybdenite associated with scheelite in the feldspar-quartz mineral vein of Nanyantian was 151.0±1.3Ma, younger than the age of skarn mineralization, indicating a later mineralization event. The skarn-type scheelite was enriched in light rare earth elements with negative Eu anomaly (δEu=0.46). The average content of ∑REE, Mo and Sr in skarn scheelite were 65.60, 240.16 and 883.43μg/g, respectively. Feldspar-quartz vein-type scheelite showed a flat rare earth pattern with positive Eu anomaly (δEu=2.8) and average content of ∑REE, Mo and Sr were 194.40, 16.01 and 129.26μg/g, respectively. respectively. The skarn scheelite had a relatively low and uniform 87Sr/86Sr value of 0.71319 to 0.71491, indicating that the ore-forming fluids were mainly magmatic-hydrothermal in origin, whereas feldspar-quartz vein type scheelite had a wide 87Sr/86Sr range of 0.71537 to 0.72803, with an average of 0.72079, characteristic of metamorphic fluids. CONCLUSIONS The differences in trace and rare earth element contents between two types of mineralization indicate that they have different fluid sources. The negative Eu anomaly of the skarn-type scheelite indicates a high oxygen fugacity environment, whereas the feldspar-quartz vein-type scheelite is formed in a reductive environment in terms of positive Eu anomaly. Sr isotopes of two different types of scheelite display a feature of binary mixing, indicating that feldspar-quartz vein-type scheelite has a superimposed transformation effect on skarn-type scheelite, and the strong metasomatism of ore-forming fluids and surrounding rocks is the key to the formation of scheelite.

BACKGROUND The Huize ultra-large lead-zinc deposit is a typical MVT or HZT type deposit in the lead-zinc polymetallic belt. This deposit is known as a unique metallogenic system and germanium enrichment. Due to the low mineralization temperature and lack of suitable dating minerals, the age of the ore deposits has been controversial. OBJECTIVES To precisely date the mineralization age by Negative Thermal Ionization Mass Spectrometry (NTIMS) Re-Os isotope analyses and discuss the Himalayan metallogenic dynamic process in the Huize ultra-large lead-zinc deposit. METHODS NTIMS Re-Os isotope analyses were carried out on pyrite, galena, and sphalerite samples collected from the Huize ultra-large lead-zinc deposit. The Re-Os isochron age from the pyrite, galena, and sphalerite samples was used to constrain mineralization age. The initial 187Os/188Os values were used to trace the material sources. RESULTS The Re-Os isochron age of the pyrite samples is 40.7±2.6 Ma (2σ, n=9) with a model weighted average age of 40.0±2.6 Ma (2σ, n=8). The sphalerite and galena samples have model ages of 38.24±0.41 Ma and 36.57±0.40 Ma, respectively. Furthermore, the initial 187Os/188Os values of the pyrite samples vary from 0 to 0.26, whereas those of the sphalerite and galena samples are 0.46 and 0.41, respectively. CONCLUSIONS The Re-Os isochron ages indicate that the mineralization for the Huize ultra-large lead-zinc deposit occurred during the Eocene period. Based on regional ore controlling structure, tectono-lithofacies alteration characteristics in Northeastern Yunnan and the isochron ages results, a two-stage (Yanshanian and Himalayan) tectonic-fluid metallogenic model for the Huize Ultra-large lead-zinc deposit is inferred.

BACKGROUND The Kunyang phosphate deposit in central Yunnan is the largest marine sedimentary phosphorite deposit in China. The deposit is hosted in black shale of the Lower Cambrian Meishucun Formation. However, there is still some controversy on the material source of the phosphorite and the deposition age of the black shale. OBJECTIVES To precisely date the black shale and provide direct constraint for the depositional age of the phosphorite and to better understand the successive depositional environment evolution from the phosphorite to black shale in vertical profiles. METHODS Negative Thermal Ionization Mass Spectrometry (NTIMS) Re-Os isotope tracer and dating studies were performed on phosphorite of Zhongyicun Member and black shale of Shiyantou Member in the Kunyang phosphate deposit. RESULTS The Re-Os isochron age of black shale in the Shiyantou Member is 521.9±5.4 Ma, which directly constrains the deposition age of black shale in the Kunyang Phosphate deposit. The phosphorite and black shale samples have initial 187Os/188Os values from 0.6576 to 0.7671 and of 0.887, respectively. The phosphorite and black shale samples have 187Re/188Os values of 2.582-240.5 and 96.24-341.8, respectively. The δEu and δCe values of trace elements in the phosphorite and black shale show changes from low to high in the vertical profile. This evidence indicates that the formation of the Kunyang phosphorus deposit occurred in the period of rapid erosion in the mainland and a large amount of terrigenous debris involvement in diagenesis-mineralization also occurred. CONCLUSIONS Based on previous studies, the atmospheric oxygen content increased rapidly, aggravating the weathering of the continental crust and the input of a large number of highly radioactive terrestrial Os caused the initial 187Os/188Os initial ratio to increase gradually during the Cambrian Period. In addition, due to the rise of the global sea level, the paleo-marine environment of the Lower Cambrian Meishucun gradually changed from shallow water oxidization to deep water reduction. The Kunyang phosphorus deposit formed during the early stages of the sea-inward-cycle sedimentation.

We examined the effects of temperature on SOC mineralization rate (Cmin) and enzyme kinetic parameters in soils of two different latitudinal forests, i.e., broad-leaved Korean pine forest in Changbai Mountain at higher latitude and evergreen broad leaved forest in Dinghu Mountain at lower latitude. The results showed that the soil Cmin increased with temperature, and the Cmin and ...) of the Changbai Mountain forest soil were higher than those of the Dinghu Mountain forest soil. The maximal rates of velocity (Vmax) and the half saturation constant (Km) of the Changbai Mountain forest soil were higher relative to the Dinghu Mountain soil for both soil β glucosidase (βG) and N-acetyl-β-D-glucosaminidase (NAG), but being opposite for catalytic efficiency (Vmax/Km). Both Vmax and Vmax/Km of βG and NAG increased with the increase of incubation temperature, while Km decreased, i.e., the affinity of enzymes to the substrate were increased. Inconsistent with the soil...), ...) and Q10(Km) of the soil βG were higher in Dinghu Mountain forest soil than those in the Changbai Mountain forest soil. The mechanisms underlying the effects of temperate variation on Cmin and the enzyme kinetic parameters were different, and thus the temperature sensitivity of Cmin and enzyme kinetic parameters should be considered differentially in the models of soil biochemical process. [ABSTRACT FROM AUTHOR]