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This paper presents an efficient cascade calibration method with an improved Levenberg–Marquardt and sine–cosine hybrid algorithm to enhance the absolute positioning accuracy of robotic grinding systems. To expedite convergence in the Levenberg–Marquardt algorithm, a dynamic adaptive weight mechanism is introduced, enhancing global and local search capabilities. Furthermore, a novel learning rate, combining exponential and cosine functions, addresses local optima in the algorithm. The improved Levenberg–Marquardt algorithm is employed to obtain suboptimal values for robot kinematic parameter deviations. Subsequently, these values are used as central points for generating a candidate solution set in the sine–cosine algorithm, resulting in more accurate kinematic parameter deviation identification. This innovative dual-search optimization approach combines the two algorithms. Experimental results confirm the substantial improvements in absolute positioning accuracy and surface machining precision achieved by the proposed model, with the calibration method's effectiveness verified through experimentation. [ABSTRACT FROM AUTHOR]

The precision of workpiece machining is critically influenced by the geometric errors in the kinematics of grind robots, which directly affect their absolute positioning accuracy. To tackle this challenge, this paper introduces a logistic-tent chaotic mapping Levenberg Marquardt algorithm designed to accurately identify and compensate for this geometric error. the approach begins with the construction of a forward kinematic model and an error model specific to the robot. Then the algorithm is adopted to identify and compensate for the geometric error. The method establishes a mapping interval around the initial candidate solutions derived from iterative applications of the Levenberg Marquardt algorithm. Within this interval, the logistic-tent chaotic mapping method generates a diverse set of candidate solutions. These candidates are evaluated based on their fitness values, with the optimal solution selected for subsequent iterations. Empirical compensation experiments have validated the proposed method's precision and effectiveness, demonstrating a 6% increase in compensation accuracy and a 47.68% improvement in efficiency compared to existing state-of-the-art approaches. This process not only minimizes the truncation error inherent in the Levenberg Marquardt algorithm but also significantly enhances solution efficiency. Moreover, simulation experiments on grind processes further validate the method's ability to significantly improve the quality of workpiece machining. [ABSTRACT FROM AUTHOR]

Achieving high-precision manufacturing of optical components requires improving the absolute positioning accuracy of the robot to the highest possible level. Identifying the robot's kinematic parameters and compensating for kinematic errors are effective methods for improving the robot's positioning accuracy. This paper proposes a hybrid algorithm that combines the Levenberg–Marquardt algorithm and an opposition-based learning squirrel search algorithm to identify the kinematic parameters of a polishing robot. Firstly, the Levenberg–Marquardt algorithm is utilized to solve the suboptimal values of kinematic parameter deviations. Secondly, an opposition-based learning strategy is integrated into the standard squirrel search algorithm to increase the diversity of the population and prevent the population from getting stuck in local optima. The suboptimal values obtained by the Levenberg–Marquardt algorithm are subsequently used as the central values to generate the initial population for the opposition-based learning squirrel search algorithm, which helps identify more accurate kinematic parameter deviations. Ultimately, the kinematic parameters of the robot are effectively calibration. The calibration experimental results showed that the proposed method achieved a high level of calibration accuracy, resulting in a 62.61% improvement in absolute positioning error compared to before calibration. Offline machining experiments have validated the effectiveness of LM-OBLSSA in reducing deviations in the dwell points of optical components during the machining process. [ABSTRACT FROM AUTHOR]

With the growing prosperity of optical systems, the demand for high-precision optical components is becoming increasingly urgent. The mid-spatial frequency error generated on the optical components surface during the manufacturing process has become a bottleneck that restricts the improvement of the manufacturing accuracy of optical components. In this review, the processing techniques and polishing principles for optical components manufacturing are first briefly described and the source of mid-spatial frequency error is analyzed in detail. Then, several widely adopted suppression techniques in optical components manufacturing for mid-spatial frequency error are introduced in detail, such as the optimization methods for polishing path and polishing tool structure, and ion beam layer removal method. Moreover, their basic concepts, polishing mechanisms, development history, and characteristics are presented. Finally, the development of suppression techniques of mid-spatial frequency error for optical polishing is summarized and prospected. This paper analyses the problems of mid-spatial frequency error in optical components manufacturing, which may be worth investigating in the future. [ABSTRACT FROM AUTHOR]

The electrochemical stability window of the electrolyte solution limits the energy content of non-aqueous lithium metal batteries. In particular, although electrolytes comprising fluorinated solvents show good oxidation stability against high-voltage positive electrode active materials such as LiNi0.8Co0.1Mn0.1O2 (NCM811), the ionic conductivity is adversely affected and, thus, the battery cycling performance at high current rates and low temperatures. To address these issues, here we report the design and synthesis of a monofluoride ether as an electrolyte solvent with Li-F and Li-O tridentate coordination chemistries. The monofluoro substituent (-CH2F) in the solvent molecule, differently from the difluoro (-CHF2) and trifluoro (-CF3) counterparts, improves the electrolyte ionic conductivity without narrowing the oxidation stability. Indeed, the electrolyte solution with the monofluoride ether solvent demonstrates good compatibility with positive and negative electrodes in a wide range of temperatures (i.e., from −60 °C to +60 °C) and at high charge/discharge rates (e.g., at 17.5 mA cm−2). Using this electrolyte solution, we assemble and test a 320 mAh Li||NCM811 multi-layer pouch cell, which delivers a specific energy of 426 Wh kg−1 (based on the weight of the entire cell) and capacity retention of 80% after 200 cycles at 0.8/8 mA cm−2 charge/discharge rate and 30 °C. The energy content of non-aqueous lithium batteries is limited by the electrochemical stability window of the electrolyte solution. Here, the authors report a monofluoride ether-based electrolyte to stabilize high-voltage lithium metal batteries at high current rates and low temperatures. [ABSTRACT FROM AUTHOR]

Cryogenic transmission electron microscopy (cryo-TEM) is a valuable tool recently proposed to investigate battery electrodes. Despite being employed for Li-based battery materials, cryo-TEM measurements for Na-based electrochemical energy storage systems are not commonly reported. In particular, elucidating the chemical and morphological behavior of the Na-metal electrode in contact with a non-aqueous liquid electrolyte solution could provide useful insights that may lead to a better understanding of metal cells during operation. Here, using cryo-TEM, we investigate the effect of fluoroethylene carbonate (FEC) additive on the solid electrolyte interphase (SEI) structure of a Na-metal electrode. Without FEC, the NaPF6-containing carbonate-based electrolyte reacts with the metal electrode to produce an unstable SEI, rich in Na2CO3 and Na3PO4, which constantly consumes the sodium reservoir of the cell during cycling. When FEC is used, the Na-metal electrode forms a multilayer SEI structure comprising an outer NaF-rich amorphous phase and an inner Na3PO4 phase. This layered structure stabilizes the SEI and prevents further reactions between the electrolyte and the Na metal. The solid electrolyte interphase (SEI) strongly affects the cycling behaviour of rechargeable alkali metal cells. Here, the authors investigate via cryo-electron microscopy the SEI formed on a Na metal electrode using fluoroethylene carbonate-containing electrolyte. [ABSTRACT FROM AUTHOR]

The ultimate bearing capacity of single pile is very important to engineering safety, so correctly predicting its value becomes an important part of engineering safety. Based on the traditional exponential curve model, a parameter optimization algorithm of the exponential curve model of single pile bearing capacity, which combines the golden section method and the linear least square method, is proposed. In order to verify the reliability of the proposed optimization algorithm, the measured data of the building engineering in the literature were optimized and calculated. Through comparison, it is found that the optimization algorithm is closer to the measured value than the traditional exponential curve model algorithm, which can better guide the engineering practice, and verify the effectiveness and superiority of the proposed parameter optimization method. [ABSTRACT FROM AUTHOR]

Highlights: A creative cooperative strategy involving silk fibroin/sericin is proposed for stabilizing high-performance flexible Li–S full batteries with a limited Li excess of 90% by simultaneously inhibiting lithium dendrites, adsorbing liquid polysulfides, and anchoring solid lithium sulfides. Such fabric Li–S full batteries offer high volumetric energy density (457.2 Wh L−1), high-capacity retention (99.8% per cycle), and remarkable bending capability (6000 flexing cycles at a small radius of 5 mm). Lithium–sulfur batteries are highly appealing as high-energy power systems and hold great application prospects for flexible and wearable electronics. However, the easy formation of lithium dendrites, shuttle effect of dissolved polysulfides, random deposition of insulating lithium sulfides, and poor mechanical flexibility of both electrodes seriously restrict the utilization of lithium and stabilities of lithium and sulfur for practical applications. Herein, we present a cooperative strategy employing silk fibroin/sericin to stabilize flexible lithium–sulfur full batteries by simultaneously inhibiting lithium dendrites, adsorbing liquid polysulfides, and anchoring solid lithium sulfides. Benefiting from the abundant nitrogen- and oxygen-containing functional groups, the carbonized fibroin fabric serves as a lithiophilic fabric host for stabilizing the lithium anode, while the carbonized fibroin fabric and the extracted sericin are used as sulfiphilic hosts and adhesive binders, respectively, for stabilizing the sulfur cathode. Consequently, the assembled Li–S full battery provided a high areal capacity (5.6 mAh cm−2), limited lithium excess (90%), a high volumetric energy density (457.2 Wh L−1), high-capacity retention (99.8% per cycle), and remarkable bending capability (6000 flexing cycles at a small radius of 5 mm). [ABSTRACT FROM AUTHOR]

To improve the machining accuracy and stability of CNC machine tools, the lead screw is divided into several segments, and the action law of single section thermal deformation is analyzed, then the thermal deformation model of lead screw base on subsection processing is established. Then the relative relation of thermal deformation of each segment, the cumulative thermal drift of thermal deformation of each segment itself, the total thermal deformation of the free end of lead screw, and the relationship between them are obtained. Then, a segmented thermal compensator based on PLC for CNC system is developed. The thermal error of each segment of the lead screw is detected and compensated separately, and then the thermal error of the segment where the machine tool worktable moves to the different segment of the lead screw is compensated. Tests show that the segmented thermal compensator has achieved good actual compensation effect, so that the positioning error caused by thermal deformation of each shaft can be reduced by more than 50%. [ABSTRACT FROM AUTHOR]

Using a co-precipitation approach, we introduce Co into LiNi0.5Mn1.5O4 to prepare a series of Co-doped cathode materials in which the Co substitutes partial Ni and Mn. We then systematically study the effects of Co doping at these various sites. The structural and electrochemical properties are investigated by means of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller analysis, galvanostatic charge–discharge tests, and electrochemical impedance spectroscopy. The Co-doped samples experience a slight capacity loss, but their cycling stability and rate properties are significantly improved. When Ni and Mn are simultaneously substituted, the capacities at 0.1 C and 2.0 C of a battery using this doped material as the cathode stay at 99.7% and 96.8%, respectively, after 80 cycles, which is much better than the results for a battery with undoped material as the cathode. [ABSTRACT FROM AUTHOR]

The incorporation of inorganic fillers into poly(ethyleneoxide)(PEO)-based solid polymer electrolytes (SPEs) is well known as a low-cost and effective method to improve their mechanical and electrochemical properties. Porous zeolitic imidazolate framework-8 (ZIF-8) is firstly used as the filler for PEO-based SPEs in this work. Due to the introduction of ZIF-8, an ionic conductivity of 2.2 × 10−5 S/cm (30 °C) is achieved for the composite SPE, which is one order of magnitude higher than that of the pure PEO. ZIF-8 also accounts for the broader electrochemical stability window and lithium ion transference number (0.36 at 60 °C) of the composite SPE. Moreover, the improved mechanism of ZIF-8 to the composite SPE is investigated by zeta potential and Fourier transform infrared spectrograph characterizations. The stability at the composite SPE/lithium interface is greatly enhanced. The LiFePO4||Li cells using the composite SPE exhibit high capacity and excellent cycling performance at 60 °C, i.e., 85% capacity retention with 111 mA·h/g capacity retained after 350 cycles at 0.5 C. In comparison, the cells using the pure PEO show fast capacity decay to 74 mA·h/g maintaining only 68 capacity. These results indicate that the PEO-based SPEs with ZIF-8 are of great promise for the application in solid-state lithium metal batteries. [ABSTRACT FROM AUTHOR]

Correction to: I Nature Communications i https://doi.org/10.1038/s41467-023-36793-6, published online 25 February 2023 Supplementary Figure 30 of this article contained an error. These authors contributed equally: Guangzhao Zhang, Jian Chang. [Extracted from the article]

NaV(PO)/C composite nanofibers are prepared successfully through a coaxial electrospinning technique and subsequent calcination. The diameter of the prepared nanofibers is uniformly distributed (about 100∼200 nm), and the composite nanofibers (NF-NVP/C) contain NaV(PO) nanofibers and carbon nanofibers, and NaV(PO) nanoparticles with diameters of 5-10 nm are embedded into the composite nanofibers. The NF-NVP/C anode exhibits a high reversible capacity 189.9 mAh/g at a current rate of 0.2 C (1 C=118 mA/g) in the voltage range of 0.01-3.00 V (vs. Na/Na). Even at high rates of 5 and 10 C, this anode displays discharge capacities of 105.1 and 80.4 mAh/g at the second cycle and capacity retentions of 83 and 77% after 200 and 500 cycles, respectively. A sodium-ion full cell with NF-NVP/C as the electroactive material of both positive and negative electrodes presents two average operating voltages at ∼0.5 and ∼1.5 V and delivers a reversible capacity of 106.2 mAh/g at a current density of 100 mA/g in a voltage range of 0.01-4.00 V. The outstanding electrochemical performance is attributed to the unique nanofiber structure and uniform distribution of NVP nanoparticles in the highly conductive carbon matrix. [ABSTRACT FROM AUTHOR]

The effect of pH value on the electrostatic layer-by-layer self-assembly and the photo-responsive behavior of Poly{2-[4-(4-ethoxyphenylazo)phenoxy]ethyl acrylate- co-acrylic acid} (PEAPE) was studied. Results show that in the studied pH value range, the lower the pH value is, the higher is the UV-vis absorbance and the larger is the thickness of the multilayer films. FTIR studies indicate that the azo polyelectrolyte exhibits a different ionization degree in solutions with different pH values. The higher absorbance and the larger thickness of the layer-by-layer films can be attributed to the low ionization degree and the shrinkage conformation of PEAPE in the solution with low pH values. FTIR analysis also confirms that the driving force for layer-by-layer self-assembly of PEAPE and PDAC is the electrostatic interaction. [ABSTRACT FROM AUTHOR]