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The high-field-strength elements in diorite mainly occur in insoluble minerals (hornblende, zircon, etc.). The recoveries of high-field-strength elements, especially zirconium and hafnium, are low due to the conventional sealed acid digestion method. To solve this problem, according to the occurrence state of high-field-strength elements, this study added the pre-digestion process, and deigned three factor and three--level orthogonal experiment including the amount of reagents (hydrofluoric acid, nitric acid) and the digestion lime. According to the experiment, the optimal reagent addition amount was 2 mL hydrofluoric acid and 1 mL nitric add, and the digestion lime was 36 hours. The most important factor affecting the recoveries of high field strength elements-was hydrochloric aid. This study added 0.1% hydrochloric add (volume ratio) to the dissolved solution to ensure the stability of high field strength elements. High-field-strength elements contents of diorite in the Beishan area were determined by the method, which was consistent-with the results determined by alkali fusion and X-ray fluorescence methods. Detection Units of the method were in the range of 0.004 -- 2.5 µg/g with relative standard deviations of 1.5%-8.4% and recoveries of 93.0%-108%.As a result, accurate analysis of high-field-strength elements in diorite is realized. [ABSTRACT FROM AUTHOR]

Cyclosporine-A (CsA) is currently used to treat immune rejection after organ transplantation as a commonly used immunosuppressant. Liver injury is one of the most common adverse effects of CsA, whose precise mechanism has not been fully elucidated. Pregnane X receptor (PXR) plays a critical role in mediating drug-induced liver injury as a key regulator of drug and xenobiotic clearance. As a nuclear receptor, PXR transcriptionally upregulates the expression of drug-metabolizing enzymes and drug transporters, including cytochrome P4503A (CPY3A) and multidrug resistance-associated protein 2 (MRP2). Our study established CsA-induced cytotoxic hepatocytes in an in vitro model, demonstrating that CsA dose-dependently increased the aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) level secreted in the HepG2 cell supernatant, as well as viability and oxidative stress of HepG2 cells. CsA also dose-dependently decreased the PXR, CYP3A4, CPY3A5, and MRP2 levels of HepG2 cells. Mechanistically, altering the expression of PXR, CYP3A4, CYP3A5, and MRP2 affected the impact of CsA on AST and LDH levels. Moreover, altering the expression of PXR also changed the level of CYP3A4, CPY3A5, and MRP2 of HepG2 cells treated by CsA. Our presented findings provide experimental evidence that CsA-induced liver injury is PXR tightly related. We suggest that PXR represents an attractive target for therapy of liver injury due to its central role in the regulation of the metabolizing enzymes CYP3A and MRP2-mediated bile acid transport and detoxification. [ABSTRACT FROM AUTHOR]

The use of Constant‐stress accelerated degradation tests (CSADT) modeling is an effective way to assess the reliability of products. However, when conducting reliability experiments, the data collected may come from various sources such as different manufacturing batches, equipment, and operators. This can result in reduced accuracy of the test evaluations. In this research paper, we propose optimal designs for the Wiener constant‐stress accelerated degradation model that take into account the heterogeneity of manufacturing batches and individual differences. Our goal is to minimize the variability of the mean time to failure (MTTF) while working within a specified budget, test time, and available test units. To achieve this, we utilize particle swarm optimization (PSO) to find the best solution based on a complex objective function. We also compare our model with others using degradation data from LEDs, showing that our model has a better goodness‐of‐fit. Finally, we present examples of optimal CSADT plans under different constraints and conduct sensitivity analysis. [ABSTRACT FROM AUTHOR]

Desiccation shrinkage is a key factor contributing to the engineering hazards in expansive soil. To inhibit the initiation and expansion of cracks, a composite improvement approach using biochar and sisal fibers was applied to expansive soil from Nanning, Guangxi. An orthogonal test method was employed to conduct desiccation cracking tests on the improved soil, investigating the effects of biochar and sisal fibers on crack length, crack ratio and crack width. The results indicate that different proportions of sisal fibers and biochar can effectively inhibit soil crack development. The biochar content is the primary factor affecting crack length, while sisal fibers mainly inhibit the development of crack ratio and average crack width. The optimal proportion for composite improvement approach was found to be 6‰ of 3 cm sisal fibers and 4% biochar. The study findings can provide a new approach for the expansive soil improvement and for controlling engineering problems caused by soil cracking.

Aiming at the problems of inaccurate judgment of linear range and the inability to measure dynamically of traditional compliance measuring instrument of loudspeaker spider，a spider compliance measurement system based on STM32 was designed. In the hardware design, the function of auto-measurement was realized by motion control circuit and data acquisition circuit, and a low voltage ripple DC voltage regulator was used to make the sampling result more accurate. In the part of the software design, the sliding mean filter algorithm was used to reduce the output error, the least square algorithm was used to improve the fitting goodness, and the linear approximation was used to obtain the linear range of the spider. The experiments show that the resolution of the system is high, the compliance curve and the linear range of the spider can be obtained accurately.

As the penetration rate of wind power systems is rising, which causes the overall system's inertia to decline, the power system's capacity to regulate frequency will be negatively affected. Therefore, this paper investigates the inertia control of doubly fed induction generation, and an energy storage system is installed in the wind farm to respond to the frequency deviation. First, a fuzzy control-based virtual inertia adaptive control strategy is presented. The goal of dynamic adjustment of the virtual inertia coefficient is realized by taking into account the uncertain factors of wind speed and frequency change rate. A recovery strategy based on the energy storage system's level of charge is employed to prevent overcharging and over-discharging of the battery. Then, a weight factor based on frequency deviation is introduced to combine the droop output of the energy storage system with the virtual inertia output of the doubly fed induction generation, and the joint output mode of the wind storage system is determined in each stage of primary frequency regulation. Finally, the simulation verification is performed using the wind storage system simulation model created by MATLAB. The comparison results with other control methods prove that the proposed method is effective. [ABSTRACT FROM AUTHOR]

The sealing of the drive shaft assembly of the impact screw drilling tool is very easy to fail under the coupling of high temperature and 3-D compound motion, which limits the popularization and application of the impact screw drilling tool. In order to study the sealing characteristics and parameter sensitivity of the drive shaft assembly under the coupling effect of high temperature, high speed and reciprocating motion, the contact surface formed by the shaft and the slip ring was defined as the main sealing surface, and the contact surface formed by the O-ring and the groove bottom was defined as the secondary sealing surface. Based on the contact pressure of the main sealing surface, numerical simulation was performed on the relevant parameters that affect the sealing characteristics of the combined ring, and the influence of friction coefficient, O-ring diameter, carbon fiber content and reciprocating speed on the sealing performance of the combined ring was studied. Studies have shown that with the increase of friction coefficient, the contact pressure and Mises stress of the primary and secondary sealing surfaces in the pre-compression state increase, the contact pressure of the primary and secondary sealing surfaces in the static seal state decreases,and the Mises stress of the slip ring increases. In the dynamic seal state,when the friction coefficient of left and right stroke is 0. 01, 0.02, 0.03,the contact pressure fluctuation range is small. When the friction coefficient is 0.04,the contact pressure fluctuation range is larger. It is reasonable to recommend that the friction coefficient is less than 0.04. As the diameter of the O-ring and the carbon fiber content increase, the contact pressure of the primary and secondary sealing surfaces and the Mises stress of the O-ring and slip ring in the precompression state increase, and the contact pressure and Mises stress of the primary and secondary sealing surfaces in the static and dynamic sealing states increase. With the increase of reciprocating speed, the average contact pressure of the primary and secondary sealing surfaces in the right stroke is larger than that in the left stroke. The contact pressure of the left stroke shows a decreasing trend; on the contrary, the average value of the contact pressure and the stress difference between the left and right strokes increase. The research results provide guidance and reference for the selection and use of sealing rings of impact screw drilling tools in the future. [ABSTRACT FROM AUTHOR]