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The scale factor of each relative gravimeter must be calibrated both before and after the fieldwork of a terrestrial gravity survey, to reduce uncertainties and ensure high precision. Conventionally, such calibration is a time-consuming process performed following well-established baselines. We propose a new Bayesian method to estimate the scale factor in a hybrid gravity network that includes several absolute gravity observation stations. In this approach, the scale factor is estimated as a hyperparameter using the Akaike Bayesian information criterion and using known absolute gravity stations in the network or/and calibrated instruments as constraints. Testing the sensitivity of the gravity values and the residuals of the gravity difference between two successive stations to the change of the scale factor demonstrates the robustness of this method. We also test the sensitivity of the estimated scale factor in the presence of Gaussian noise and the non-linear instrumental drift rate. Moreover, if the maximum absolute gravity interval is greater than 60 per cent of the range of gravity values in the network, or if the known scale factors of calibrated gravimeters are well calibrated, this approach can provide reasonable estimates of the daily drift rate and the unknown scale factors, where the latter has an error of <3 × 10−5. We apply this approach to real gravity campaign data from Yunnan in China and use a cross-validation method to compare estimated gravity values and corresponding gravity values obtained from absolute gravity observations at the same stations, to validate how the proposed method improves estimation accuracy of the gravity value at each station. [ABSTRACT FROM AUTHOR]

In this paper, a novel time-varying gain extended state observer (ESO)-based moving sliding mode control method is proposed for anti-sway and positioning control of two-dimensional underactuated overhead cranes. The designed moving sliding mode surface can adjust its slope in real time according to the state variable errors; in addition, a dynamic exponential term is added into the moving sliding mode surface so as to drive any initial state variable errors into the sliding surface rapidly, and thereby the robustness of crane systems is improved. Then, a chattering-free reaching law is designed to realize fast convergence of the system state errors, and the input is modelled as a saturated one due to the fact the motor torque is bounded and the control law and adaptive updating law of switching gain are derived in the sense of Lyapunov function, so the stability can be guaranteed even under the input saturation. Moreover, to suppress the matched and unmatched disturbance occurring in crane dynamic systems, a time-varying gain ESO is constructed to estimate the lumped disturbance, then the estimated value is used for feedforward compensation to establish the controller. Finally, the simulation results confirm the effectiveness of the proposed controller. [ABSTRACT FROM AUTHOR]

In order to solve the problem that the blurred image of a moving object decreases accuracy in the process of detecting the payload swing angle of an overhead crane based on vision, and the tracking failure caused by the drastic change of grey targets, a robust real-time detection method of the load swing angle of a bridge crane is proposed. This method uses a spherical marker attached to the load, which is insensitive to rotation and tilt when it is detected. First, it uses the mean shift algorithm combined with Kalman filter to track the moving objects in the image plane continuously, and then integrates the method of minimum area circle to detect the spherical marker image in the region of interest accurately and quickly. Finally, combined with the geometric method, the real-time swing angle is calculated. In addition, the angle diagram method is used to increase the speed of calculating the swing angle. The experimental results show that the method is effective for detecting the load target swing angle of different trolley motion speed. [ABSTRACT FROM AUTHOR]

Ti3C2Tx MXene prepared by the removal of Al from the Ti3AlC2 precursor is an attractive 2D material with attractive physical and chemical properties. However, the measured properties of Ti3C2Tx, especially the microwave absorption (MA) properties, vary greatly in the literature. To illustrate the influence of the dominant factors on the MA property differences of Ti3C2Tx, different sized Ti3AlC2 precursors and processing conditions were investigated. The Ti3AlC2 precursors were synthesized by pressureless sintering a Ti/Al/graphite mixture at 1450 °C for 30 min, 60 min and 120 min, respectively. Ti3C2Tx flakes having various lateral dimensions and thicknesses were obtained after etching the Ti3AlC2 precursors in 40% HF solution for 2 h. The MA test showed the largest Ti3C2Tx flakes by etching of the 120 min-prepared Ti3AlC2 demonstrated the minimum reflection loss (RL) value of − 28.11 dB at 10.24 GHz, indicating the larger Ti3C2Tx flakes, the richer in surface terminations which dissipate more microwave energy. The etching times from 0.5 h to 20 h was adopted to enrich the surface functional groups which contribute to the enhanced MA properties. However, the prolonged etching time up to 20 h caused the poor MA performance. Furthermore, surface chemistry of Ti3C2Tx affected the MA behavior. Annealing Ti3C2Tx at 750 °C removed some surface groups, thus deteriorating the MA property. This work is conductive to the practical applications of MXenes. [ABSTRACT FROM AUTHOR]

Ti3C2Tx MXene with good thermal conductivity and microwave absorption (MA) properties is an attractive candidate used in 5G communication applications to dissipate the accumulated heat and absorb electromagnetic energy. Ti3C2Tx has good MA properties partially due to the contribution of the polarization loss induced by the surface terminations; however, these terminations, especially the −F, are easily removed under thermal environment. To investigate the influence of the annealing conditions on the MA properties, Ti3C2Tx was vacuum-annealed at 150, 350, and 550 °C, respectively, for 1 h. The 150 °C-annealed Ti3C2Tx demonstrated the best reflection loss (RL) value of − 15.10 dB at 9.92 GHz as compared with the pristine Ti3C2Tx (− 11.07 dB at 7.92 GHz) and resultant products annealed at 350 °C (− 3.60 dB at 13.68 GHz) and 550 °C (− 4.97 dB at 11.28 GHz). Annealing at 150 °C for 1 h removed part of −F, but tuned the impedance matching of Ti3C2Tx, thus improving the MA properties. Further prolonging the annealing time from 1 to 4 h at 150 °C induced a slight deterioration on the MA properties mainly due to −F desorption. This work confirms the application temperature of Ti3C2Tx as an attractive MA material used in 5G communication. [ABSTRACT FROM AUTHOR]

Rationale: (E)‐4‐Hydroxy‐2‐nonenal (HNE) is a reactive secondary product of lipid oxidation with biological significance. The analysis of HNE is a challenge due to its volatility and high activity. Developing sample preparation and analytical tools for the determination of free HNE is crucial for better understanding the actual level of free HNE in meat products. Methods: Liquid nitrogen freezing, subzero‐temperature extraction and derivatization were employed for meat sample treatment. Liquid chromatography/tandem mass spectrometry with electrospray ionization in negative ion mode was used for the determination of free HNE after isotope‐coded derivatization. Results: High repeatability and good recoveries with a limit of quantification as low as 0.25 pmol/g were found. Nineteen out of 24 samples, including chilled/processed meat products and meat‐based instant foods, were found to contain free HNE with a range of 0.014–1.160 nmol/g. Conclusions: The proposed method showed satisfactory reliability, sensitivity and accuracy. We believe that such a sample preparation strategy will provide a powerful tool for better understanding the actual level of free HNE in meat products. [ABSTRACT FROM AUTHOR]

Background: Microcalcification is one of the most reliable clinical features of the malignancy risk of breast cancer, and it is associated with enhanced tumour aggressiveness and poor prognosis. However, its underlying molecular mechanism remains unclear.Methods: Clinical data were retrieved to analyse the association between calcification and bone metastasis in patients with breast cancer. Using multiple human breast cancer cell lines, the osteogenic cocktail model was established in vitro to demonstrate calcification-exacerbated metastasis. Migration and invasion characteristics were determined by wound healing and transwell migration. mRNA and protein expression were identified by quantitative PCR and western blotting. Metabolic alterations in breast cancer cells were evaluated using Seahorse Analyser.Results: The osteogenic differentiation of human breast cancer cells activated the classical TGF-β/Smad signalling pathway and the non-canonical MAPK pathway, which, in turn, exacerbated the progression of epithelial-mesenchymal transition (EMT). The metabolic programme switched to enhancing mitochondrial oxidative phosphorylation (OXPHOS) upon osteogenic differentiation. Rotenone was used to inhibit the OXPHOS complex during osteogenesis to block mitochondrial function, consequently reversing the EMT phenotype.Conclusions: This study provides important insights into the mechanisms involved in breast cancer bone metastasis, and outlines a possible strategy to intervene in OXPHOS for the treatment of breast tumours. [ABSTRACT FROM AUTHOR]