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Underground pyrolysis of tar-rich coal is a green and low-carbon technology that effectively extracts oil and gas resources from coal. It represents the forefront of clean and low-carbon utilization of coal. The nano-pores present in coal play a vital role in the adsorption and desorption of tar and gas during the underground pyrolysis process. Therefore, understanding the evolution of nano-pore structure under underground pyrolysis conditions is a key scientific issue for enhancing the oil and gas yield of tar-rich coal through this process. To address this, the China Spallation Neutron Source (CSNS) - Small-Angle Neutron Scattering (SANS) technique was employed to simulate the in-situ pyrolysis environment of coal seams. This allows for the quantitative characterization of the scattering intensity, average pore size, and fractal dimension evolution of nano-pores in tar-rich coal in different heating rates and temperatures under unconfined pressure conditions. The complementary physical characterization methods such as physical adsorption (BET), thermogravimetric analysis (TG), and scanning electron microscopy (SEM) were also utilized. The research findings reveal the evolution of nano-pore structure characteristics during the underground pyrolysis of tar-rich coal. The research results demonstrate that during the underground pyrolysis process, the average pore size of nano-pores gradually increases with the rise in temperature. Nanopore development is relatively slow during the pyrolysis drying and degassing stage ( < 300 ℃), while the most significant growth occurs during the active stage (300−500 ℃), resulting in a 57.1% increase. Subsequently, nanopore development slows down during the secondary degassing stage. Importantly, it was observed that the low-medium-high temperature (≤800 ℃) pyrolysis conditions does not cause any significant changes in the surface fractal dimension (Ds) of tar-rich coal. Based on SANS spectroscopy analysis, it was discovered that the distribution of nano-pores in tar-rich coal during the pyrolysis process exhibits isotropic characteristics. This suggests that the pyrolysis reaction does not impact the directional development of nanopores in this experimental samples. Furthermore, a comparison between different heating rates (5 ℃/min and 20 ℃/min) reveals minimal influence on the average pore size and fractal dimension of nano-pores during underground pyrolysis of tar-rich coal. Notably, under slower heating rates, tar-rich coal exhibits higher overall scattering intensity, indicating more substantial development of the nano-pore structure. This, in turn, facilitates the progress of the underground pyrolysis reaction. In addition to these findings, the CSNS-SANS technique proves advantageous over the conventional characterization methods such as BET. It enables the detection of closed pores within the samples and provides experimental conditions that closely resemble the in-situ environment, thereby ensuring more reliable results.

The in-situ EBSD analysis method was used to systematically study the effect of retained austenite characteristics on the phase transformation behavior of ferritic stainless steel after the quenching and partitioning （Q&P） process. The results show that the phase transformation behavior of retained austenite during deformation is related to its grain size， distribution， and morphology， and its influence degree is arranged in descending order. Compared with inter-martensitic austenite and inter-martensite-ferrite austenite， the trigeminal and twin austenite are more prone to martensitic transformation in the early stage of deformation. This is closely related to the different strains or stresses applied to different distributed retained austenites during deformation. Compared with large-sized austenite， small-sized austenite begins to transform in the later stage of deformation， which is helpful to prolong the uniform elongation. This may be due to the higher interfacial energy and average C content of small-sized austenite， and the need for larger macroscopic stress/strain to induce martensitic transformation due to the strengthening effect of fine grains. The elongated/equiaxed austenite is easy to transform in the early stage of deformation， while the transformation of thin film-retained austenite is mainly concentrated in the later stage of deformation， which is helpful to further improve plasticity. The different transformation behaviors are due to the differences in C and N content， as well as the presence of defects such as stacking faults， dislocations， and slip.

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) method is characterized by in-situ, high space resolution and high sensitivity. Therefore, the study of LA-ICP-MS in-situ trace elements analysis in magnetite has made a rapid progress and it is widely used in geological field in recent years. An analytical method for the trace elements determination of magnetite by LA-ICP-MS using Agilent 7700X inductively coupled plasma-mass spectrometry (ICP-MS) and Photo Machines Analyte Excite 193nm laser ablation was established at the laboratory of mineralization and dynamics, Chang′an University. This method adopts multiple external standards (BIR-1G, BHVO-2G, BCR-2G and GSE-1G) as calibration standards without an internal standard. Trace element compositions of the glass standard material NIST 612 and natural magmatic magnetite BC 28 were determined by the established method to evaluate its reliability. The results show that the relative standard deviation (RSD, N=30) of trace elements in NIST 612 ranges from 1.31% to 6.33%. Compared with the recommended values and the previous reference values obtained by LA-ICP-MS, the relative error of most elements in NIST 612 is smaller than 10%. The RSD (N=30) of most elements in BC 28 is lower than 10%, and the relative error of 11 important trace elements in BC 28 is smaller than 10% compared with the reported values by LA-ICP-MS. The above results show that in-situ trace element determination of magnetite can be carried out by using the method established in this study. The analysis data is accurate and reliable, and it has a great application potential.

The morphology, distribution, and entrapped inclusions of bubbles in thick slab of X70 pipeline steels were investigated by peeling layer.The results show that the diameters of 94%bubbles in thick slab are less than 200μm;the bubbles and the entrapped inclusions are common in 8 mm depth from the slab surface, but the defects are hardly found as peeling deeper into the middle of slab, only a small number of defects are shown, presenting a random distribution in this area;the main morphology of bubbles existing in slab are single bubbles and twin bubbles, the calabash bubbles and petal bubbles are also found;the inclusions are mainly in four existent forms:oxides, aggregation in clusters, bubbles in clusters, and ash inclusions.

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Compared to the traditional strontium isotope analytical method, a micro-sample strontium isotope system study can reveal the heterogeneity of analyzed samples and is widely used in various fields of geology, such as crust-mantle interaction, genesis and evolution of magmas, open magma systems, tracing provenance of sedimentary basin and climate research. Accurate measurement of Rb-Sr isotopic ratios is the premise to apply Sr isotope in these research fields. Two detailed and widely used analysis methods for micro-sample Sr isotope measurement are microdrilling-TIMS/MC-ICPMS and LA-MC-ICPMS. These two methods have different advantages and disadvantages in sample preparation, interference correction and measurement in mass spectrometry. The greatest advantage of microdrilling-TIMS/MC-ICPMS is that this technique can acquire high quality data (external precision is better than 100×10-6, 2SD). However the tedious chemical separation is very time-consuming (about 10 days) and the chemical procedure blank must be critical to low level. The large sampling depth (100-2000 μm) and diameter (200-2000 μm) reduce the spatial resolution. However, with chemical separation this method can effectively measure samples with high Rb content. Simple sample preparation and fast analysis are the most outstanding advantages of LA-MC-ICPMS which can analyze lots of samples in a much shorter time than that of microdrilling-TIMS/MC-ICPMS. The laser spot size is mainly from 60 to 300 μm. Based on Sr contents in samples, the method of LA-MC-ICPMS improved spatial resolution, compared to microdrilling-TIMS/MC-ICPMS technique. However, without chemical separation, many kinds of interferences (e.g. Rb, Ca, Kr and REEs) hinder this technique to obtain high quality data (external precision is about 200×10-6, 2SD and accuracy is about 150×10-6). LA-MC-ICPMS is only suitable for high Sr and low Rb samples, instead of samples with high content of interferences. Further studies are required for the microdrilling-TIMS/MC-ICPMS method to improve the efficiency of chemical separation, also microdrilling technology with increasing of spatial resolution by reducing spot diameter and depth. Meanwhile, a better solution for interferences of Kr, Rb and REEs is needed for LA-MC-ICPMS in order to improve precision and accuracy of high interference samples. Instrumental sensitivity improvement is also needed to satisfy Sr isotope measurement for samples with relative low Sr content.

A portable X-ray Fluorescence Spectrometer (XRF) can be used for field analysis with the advantages of rapidity and non-destruction; the applications of hand-held XRF in in-situ analysis of cobalt-rich crust chunks and core are described. The calibration curve for cobalt-rich crusts was established using national certified reference materials such as GBW 07337, GBW 07338 and GBW 07339. The proposed method has been validated by analyzing certified reference materials; the relative standard deviation was 0.3%-3.0%, which is appropriate for analysis of cobalt-rich crust in field. The hand-held XRF was utilized for in-situ analysis of cobalt-rich crust chunks and drilling core in marine exploration. A comparison of the results from in-situ analysis of dried crust chunks and those obtained from the hand-held XRF instrument after pressed powder sample preparation is presented, and good consistencies were found for the elements of interest. The data of in-situ analysis of crust core was evaluated by comparing with that obtained from laboratory testing after powder was layered artificially; the results based on two different methods indicate that distribution features of Mn, Fe, Co, Ni and Cu are similar. The methodology has been proved to be an effective method for in-situ analysis, which can meet the need of fast evaluation of cobalt-rich crusts resources, meanwhile, the proposed method, is appropriate for distribution research of Mn, Fe, Co, Ni and Cu in original cobalt-rich crust, which is helpful for the study of mineralization in different metallogenic stages of the crust.

Nanxiaoyao gold deposit, is located in the middle of Yishu fault zone, Shandon, develops the altered type and quartz vein type ores. According to the characteristics of major and trace elements of three types of ores (including greenschist with beresitization, mylonite with pyritization and chloritization, and quartz-sulfide vein) and pyrites in Nanxiaoyao gold deposit, the characteristics of metallogenic materials and fluids, tectonic settings and metallogenic mechanism were discussed. The results show that the three types of ores are enriched in Co and Ni, and depleted in REE, indicating that their metallogenic fluids may be all from the deep, and the Eu varies from slightly negative anomaly to positive anomaly, showing that the characteristics of metallogenic fluids may be changed; the ratio of mass fraction of Au to Ag of pyrite is less than 0.5, and As is poor, indicating that the temperature of fluid is high; the formation of all ores may be related to volcanism, and the metallogenic fluid of greenschist with beresitization, and quartz-sulfide vein could be from volcanic and subvolcanic activities in Yanshanian; the protoliths of ores may be sedimentary rocks and alkaline intermediate-basic magmatic rocks, and the metallogenic materials of ores may be derived from deep mantle. In conclusion, the metallogenic materials and fluids in Nanxiaoyao gold deposit are all derived from deep; because of the upward with the volcanic-magma activity, the metallogenic environment changes from weak reduction to weak oxidation by blend of meteoric water, enhancing the Au precipitation and forming the distinct gold deposits in different tectonic settings. [ABSTRACT FROM AUTHOR]

The developments of in-situ X-ray Fluorescence (XRF) analysis techniques in the fields of Portable XRF Spectrometer, in-situ analytical methods and its applications are described in this paper. Portable XRF Spectrometer has been divided into four generations, based on the aspects of X-ray excitation sources, X-ray detectors and electrical circuit units. The paper also documents some in-situ analytical methodologies for analyzing X-ray spectra, overcoming the influence of the matrix effect, unevenness effect, moisture effect and heterogeneous effect on in-situ XRF analysis results. Finally, some applications in mineral exploration, environmental investigation, cultural relic discrimination and alloy analysis are introduced. The domestic Portable XRF Spectrometer was between generations Ⅲ and Ⅳ. The low power miniature X-ray generator and electric refrigeration semiconductor detector were dependent upon importation from foreign countries. The full digital X-ray energy spectrum collector is not yet available commercially. It is also pointed out that there are some capabilities for improving the accuracy and method detection limit of in-situ analysis. Research fields need be broadened to include the applications of Portable XRF Spectrometer.

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)