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Aiming at the problems of high manufacturing cost and easy damage of communication cable joint in the central cable type drill pipe, which is the cable transmission device for directional drilling in underground coal mine, an electromagnetic measurement while drilling（ＥＭ－ＭＷD） system used in coal mine is developed. The system is composed of special industrial computer, measuring tube, electromagnetic transmission tube, etc. It adopts the electromagnetic transmission mode with the drill pipe and the formation as the communication channel. The underground test results of coal mine show that the EM- MWD system works stably with correct measurement data and reliable electromagnetic transmission, and there is no need to use the central cable drill pipe, which not only improves the reliability of downhole directional drilling but also significantly reduces the drilling cost. The mine-used EM-MWD system could satisfy various requirements of directional drilling in coal mine.

The thixomolding technology offers distinct advantages for producing magnesium matrix composites with intricate geometries. This study explores the effects of incorporating hybrid SiC–Al2O3 particles on the microstructure, deformation, fracture, and mechanical properties of a thixomolded Mg–10Zn alloy. The composite exhibits a homogeneous distribution of Al2O3 and SiC particles within the matrix. The addition of SiC–Al2O3 reinforcements helps reduce the content of primary α -Mg solid and refine the microstructure. The composite demonstrates a yield strength of 186 MPa, an elastic modulus of 48.6 GPa, and a respectable elongation of 6.8%. The digital image correlation measurement was performed at the sample scale, unveiling overall deformation characteristics. Crystal plasticity finite element method was employed for high-fidelity microstructure, showcasing mesoscale deformation feature such as the deformation mechanism of grains adjacent to reinforcements. It was found that SiC–Al2O3 particles prevent the formation of large shear band, benefiting the ductility of the material. The post-mortem analysis using scanning electron microscope near the fracture position reveals micro-cracks inside the SiC particles. Notably, the SiC/Mg interface shows no signs of cracking, while some Al2O3/Mg interfaces are separated. Reinforcement cracking is correlated to the stress it withstands, and the mesoscale deformation analysis reveals that the reinforcement stress is increased when non-basal slip in grains adjacent to the reinforcement becomes difficult to be activated. This work serves as an example for developing Mg matrix composites through the thixomolding process. The findings of this study provide valuable insights for the design of high-performance thixomolded Mg-based composites [ABSTRACT FROM AUTHOR]

The present study investigates the mechanical behavior of a SiCp/Mg–5Zn–0.2Ca composite under tensile loading using in-situ synchrotron X-ray diffraction. The composite exhibited a yield strength of 167 MPa, ultimate tensile strength of 276 MPa, and tensile elongation of 15%. It was found that the onset of micro-yielding at a stress level of approximately 40 MPa, which is attributed to the thermal and interfacial mismatches between the SiC particles and α-Mg matrix. Furthermore, load partitioning between the SiC particles and α-Mg grains was observed following the micro-yielding event, indicating micro-load transfer from the softer α-Mg grains to the SiC particles. The occurrence of microcracks at the SiC/Mg phase interfaces after the micro-yielding event may have implications for the composite's overall fracture behavior. These findings underscore the influence of interfacial thermal mismatch on promoting micro-yielding in the composite. Several factors including reducing forming temperatures, utilizing reinforcements with lower coefficients of thermal expansion, and adjusting the alloying elements can be used to mitigate such micro-yielding effect. [ABSTRACT FROM AUTHOR]

Rationale: Saliva has been widely accepted as a more convenient alternative to serum or plasma in the field of clinical diagnosis. However, the detection of trace components in saliva has been a bottleneck problem. The aim of this work was to develop a highly sensitive and reliable method for simultaneously determining the trace steroid hormones including some with poor ionization efficiency in human saliva by liquid chromatography/tandem mass spectrometry (LC/MS)., Methods: Saliva was deproteinated by acetonitrile containing mixed isotope internal standards and extracted with methyl tert-butyl ether. The extraction solution was dried under a stream of nitrogen and the residue was derivatized using 50 mM O-ethylhydroxylamine hydrochloride in 80% methanol/water solution (v/v). The processed sample was determined by LC/MS in multiple reaction monitoring (MRM) mode., Results: The method was successfully established for the simultaneous quantification of seven steroid hormones in human saliva and showed excellent specificity and sensitivity. The limits of quantification (LOQs) of all steroid hormones were below 5 pg/mL, in particular, the LOQ of progesterone was as low as 0.15 pg/mL. The linear correlation coefficients (r) were greater than 0.9990 in the range of 2-200 pg/mL for T, DHEA, A4, P4, P5, and 17OHP4 and in the range of 5-500 pg/mL for 17OHP5. The intra-day and inter-day variability ranged from 1.86% to 7.83% and 1.95% to 10.4%, respectively. The recovery of the method ranged from 86.9% to 111.1% for all steroid hormones using three spiked concentrations., Conclusions: A novel LC/MS/MS method was developed for the simultaneous quantification of seven kinds of trace steroid hormones in human saliva. The results of the methodological study showed that the method exhibited excellent sensitivity and reliability for the evaluation of free steroid hormones in the human body. It is believed that this method could provide useful information of steroid hormone metabolism for auxiliary diagnosis of some endocrine disorders., (© 2021 John Wiley & Sons Ltd.)