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This brief proposes a calibration method for offset, gain, and timing‐skew mismatches in time‐interleaved analog‐to‐digital converters. The calibration method includes the estimation method and the correction method. The estimation method is based on the difference between the spectral distribution of the error harmonics and the input signal. The correction method adopts sequential correction. Simulation results demonstrate that the proposed method calibrated all three mismatches simultaneously and eased the limit for input signals compared with the traditional method. [ABSTRACT FROM AUTHOR]

Paraloid B-72 (B72), as a transparent, colorless polymer material, has good film-forming ability when dissolved in acetone and is widely used as a sealing material for metal artifacts. In order to analyze and evaluate the preservation performance of B72 as a sealing material on the substrate of metal artifacts, a variety of electrochemical methods, mainly electrochemical noise (EN), and scanning electron microscopy (SEM) were applied to evaluate the B72 coating. The results showed that the B72 coating had a good preservation effect at the initial stage, and its poor water resistance led to the loss of its effectiveness after a few days of immersion. Compared with conventional electrochemical methods, electrochemical noise is non-destructive, which cannot cause new corrosion on the metal substrate and can well characterize the corrosion rate of the test system, and the results of its time domain and frequency domain analyses can correspond well with the polarization resistance and impedance spectra. Electrochemical noise is an effective method for evaluating the anti-corrosion performance of material preservation coatings. [ABSTRACT FROM AUTHOR]

Traditional drilling methods often face difficulty meeting the demand for efficient and accurate coring under complex geological conditions. Cordless coring is an advanced technology that uses hydraulic lifting to carry out coring, which can achieve automation and automated and intelligent drilling operations. In this research, a new type of hydraulic lifting cordless coring drilling tool is designed. Moreover, a numerical simulation model of the fluid flow in the annulus between the spearhead and spool of the cordless coring drilling tool was established. Orthogonal simulation tests are carried out, and according to the orthogonal test data, a numerical prediction model of the spool annulus fluid field based on the Backpropagation Neural Network (BP neural network) is established. The prediction of the flow rate of the drilling fluid and the spool back-pressure ratio was obtained when the structural parameters of the spearhead and the spool annulus were different. A multi-objective optimization of the annulus flow structure of the cordless core drilling tool has been carried out. The optimization objectives include deciding the back pressure ratio of the spool overcoming the spring and the flow rate of the drilling fluid. According to the established nonlinear optimization model and based on the improved Non-dominated Sorting Genetic Algorithm II (NSGA-II) multi-objective optimization algorithm, it is verified that the convergence speed and diversity of the improved algorithm are better than those before the improvement. The simulation and experimental validation are carried out. It is verified that the flow rate of drilling fluid increased by 33.56% after optimization, and the force ratio was lowered by 5.825%. Finally, based on the simulation and optimization results, the φ96 cordless core drilling tool was manufactured on a trial basis, and on-site concrete drilling, coring, and hydraulic lifting operations were conducted for smooth coring and lifting. This study could provide an important scientific basis and technical support for the application and development of hydraulic lifting cordless coring technology. [ABSTRACT FROM AUTHOR]

Hyperspectral anomaly detection is a vital aspect of remote sensing as it focuses on identifying pixels with distinct spectral–spatial properties in comparison to their background representations. However, existing methods for anomaly detection in HSIs often overlook the spatial correlation between pixels by converting the three-dimensional tensor data into its folded form of independent signatures, which may lead to insufficient detection performance. To address this limitation, we develop an anomaly detection algorithm from a tensor representation perspective, which begins by separating the observed hyperspectral image into background and anomaly cubes. We leverage the tensor nuclear norm (TNN) to capture the inherent low-rank structure of background cube globally. This allows us to effectively model and represent the background information. To further improve the detection performance, we introduce spatial–spectral total variation (SSTV) for effectively promoting piecewise smoothness of the background tensor, aiding in the identification of anomalies. Additionally, we incorporate RX-derived attention weights-guided ℓ 2 , 1 norm. This encourages group sparsity of anomalous pixels, improving the precision of anomaly detection. To solve our proposed method, we employ the alternating direction method of multipliers (ADMM), ensuring guaranteed convergence and efficient computation. Through experiments on different kinds of hyperspectral real datasets, we have demonstrated that our method surpasses several state-of-the-art detectors. [ABSTRACT FROM AUTHOR]

Straw pulping plays a vital role in virgin pulp supply and regional agricultural residue utilization. However, a significant decrease in its production has been observed. From an environmental perspective, why has there been a sharp decrease in straw pulping? Are there any innovations in straw pulp production that alleviate the heavy environmental burdens of straw pulping? In this study, factors contributing to the decrease in straw pulp are examined. An innovative technique to produce straw pulp is introduced and its environmental performance is analyzed and compared with conventional pulping. The results show that the main reasons contributing to the environmental burdens of straw pulping lie in the difficulties in black liquor extraction and alkaline recovery for the black liquor. Technical processes are changed in the innovative technique of straw pulping through using a rapid displacement cooking process, converting black liquor into fertilizers, utilizing total chlorine-free bleaching, etc. The new technique (Case B) achieves superior environmental performance than that of the conventional technique (Case A) from a carbon metabolism perspective. Specifically, 1022.90 kg and 857.80 kg of biogenic-carbon (bio-carbon), and 594.32 kg and 628.13 kg of fossil-carbon are needed to make 1 ton of bleached straw pulp for Case A and Case B, respectively. The carbon efficiencies for Case A, Case B (when pulp is the only desired product) and Case B (when including other products) are 39.10%, 46.63% and 92.21%, respectively. The carbon factors for Case A, Case B (when pulp is the only desired product) and Case B (when including other products) are 3.66, 3.60 and 1.86 kg CO 2 -eq, respectively. In addition, the corresponding E factors, which reflect the waste generation level, are 3.20, 2.69, and 1.39 kg, respectively. The new technique for straw pulping, which follows the principle of a circular economy by fully utilizing resources and reducing the generation of waste, achieves both economic and environmental benefits. It is a promising technique for straw pulping. [ABSTRACT FROM AUTHOR]

The second harmonic generation (SHG) responses of the paraelectric and ferroelectric phases of KH 2 PO 4 (KDP) were calculated by first-principles density functional theory (DFT) calculations, and the individual atom contributions to the SHG responses were analyzed by the atom response theory (ART). We show that the occurrence of static polarization does not enhance the SHG responses of the ferroelectric KDP, and that the Kleinman symmetry is reasonably well obeyed for the paraelectric phase, but not for the ferroelectric phase despite that the latter has a larger bandgap. This is caused most likely by the fact that the ferroelectric phase has lower-symmetry local structures than does the paraelectric phase. The contribution to the SHG response of an individual K + ion is comparable to that of an individual O 2- ion. The contributions of the O 2- and K + ions arise overwhelmingly from the polarizable parts of the electronic structure, namely, from the valence bands of the O-2p nonbonding states and from the conduction bands of the K-3d states., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)