1,721,121 research outputs found
Research on the performance of PGC phase demodulation algorithm based on WTD-ESO
No full textPhase generated carrier (PGC) technology is a commonly used signal demodulation scheme. PGC demodulation is easily affected by light source intensity fluctuation, system noise and environmental disturbance. In order to improve the accuracy and robustness of PGC phase demodulation, a PGC phase demodulation algorithm combining wavelet threshold de-noising (WTD) and extended state observer (ESO) is proposed in this paper. WTD is used to preprocess the PGC interference signal with noise to effectively suppress the noise interference. A phase tracker based on ESO is constructed to estimate the phase to be demodulated, the phase change rate and the lumped disturbance in the system as the extended state, so as to achieve the accurate extraction of the phase. This algorithm can significantly improve the accuracy and dynamic response characteristics of PGC phase demodulation in complex noise environment.</p
3+1 beam laser interference lithography for preparing 3D nanostructures
No full textTargeting the demand for three-dimensional (3D) micro/nanostructure fabrication, we systematically investigate the optical field formation mechanism in non-coplanar 3+1 beams interference. It specifically elucidates the governing role of the coherent beams' incidence angle in controlling the aspect ratio of the interference patterns. Based on this theoretical framework, the 3+1 beam laser interference lithography system was constructed for studying the 3D periodic nanostructures.</p
The effect of measurement parameters on cellular mechanics detection
No full textAtomic force microscopy (AFM) is an advanced nanotechnology that can image and measure the mechanical properties of living cells in liquid environment. However, the measurement parameters will affect the mechanics data. In this work, the effects of indentation force, indentation speed, lifting height, and probe shape on the cellular mechanics detection were studied. The results showed that the indentation depth increased alongside the indentation force, while the baseline separation distance also showed an increase corresponding to the higher indentation speed, and the lifting height and cantilever shape had a significant effect on the force curves measurements. This is important for studying the measurement of cellular mechanical properties at the nanoscale
A study of noble metal films in periodic structures in relation to excitation wavelength for SERS
No full textSurface-enhanced Raman spectroscopy (SERS) has established itself as a highly sensitive technique for biochemical detection. Despite significant research progress, most SERS substrates with single-resonant plasmonic nanostructures on planar surfaces are plagued by narrowband operational constraints in SERS performance. Herein, we design a simple periodic hexagonal nanostructure to explore the impacts of noble metal film parameters on surface plasmon distribution and electric field intensity. By studying the role of noble metals in SERS structures, we derive a method for designing nanostructures tailored to target excitation wavelengths. Periodic hexagonal nanostructures fabricated via ICP etching are employed to validate the findings, achieving relatively high detection sensitivity at excitation wavelengths of 532 nm and 633 nm, respectively.</p
Tailoring 2D and 3D interference structures via multi-parameter control in a 3+1 beam laser interference system
No full textAchieving precise 3D geometric control in Laser Interference Lithography (LIL) is vital. This study simulates a 3+1 beam LIL system, exploring how wave vector, polarization, and phase modulation impact 2D/3D pattern symmetry and morphology. We found phase shifts translate patterns, polarization rotation reshapes motifs, and wave vector changes alter lattice symmetry. Thus, wave vector governs periodicity/symmetry, polarization controls morphology, and phase tunes position. This decoupled parameter control in 3+1 LIL allows fabrication of programmable structures for advanced photonics and materials.</p
Optimization of shark groove drag reduction based on CFD and genetic algorithm
No full textAn optimization of shark scale flake groove structure by genetic algorithm is proposed to enhance its drag reduction performance. The microstructure of shark scales has been shown to play a key role in reducing frictional drag and enhancing hydrodynamic efficiency. Therefore, a genetic algorithm was used to optimize the design of the groove shape of the scales to exhibit optimal performance in the fluid environment. Genetic algorithms of selection, crossover and mutation are used to find the optimal solution in the design space. The optimized design is validated by Computational Fluid Dynamics (CFD) technique. The CFD simulation results demonstrate the improved hydrodynamic performance of the optimized groove design and confirm the effectiveness of genetic algorithms in complex engineering design problems. This study provides a new research avenue to improve the hydrodynamic efficiency
PGC-Arctan demodulation method based on improved IKEF
No full textThe proposed method is an improvement on the traditional PGC demodulation technique, specifically addressing the impact of carrier phase delay, modulation depth drift, and low-frequency ambient noise on phase demodulation accuracy in phase-modulated homodyne interferometers. It utilises an improved iterative extended Kalman filtering (IEKF) approach. The algorithm enhances the iterative updating process by incorporating a damping factor into the traditional IEKF. This enables optimal estimation and correction of the parameters of the PGC quadrature signals, resulting in reduced nonlinear error in the demodulation process. Additionally, the improved algorithm achieves higher demodulation accuracy. Simulation results demonstrate the method's effectiveness in eliminating nonlinear error in phase generation carrier
The role of exercise intervention on insulin resistance
No full textInsulin resistance (IR) refers to the decrease of insulin sensitivity and the insensitivity of the body to insulin. The normal concentration of insulin cannot maintain the normal level of blood sugar, and no matter how much insulin is secreted, it cannot achieve good hypoglycemic effect, thus causing diabetes. The major target organs and tissues of IR are liver, fat and skeletal muscle. IR can be improved by lifestyle intervention, such as diet and exercise control. Exercise is a non-drug intervention to prevent and treat IR. The clinical application of exercise is more and more extensive. Because it is more convenient, economical and effective. In this article, the pathogenesis and pathophysiological process of insulin resistance are reviewed. The mechanism of intervention of exercise on insulin resistance is combed, so as to try to find the best exercise prescription for improving IR and provide useful reference for clinics.</p
Bioinspired surfaces for directional liquid transport:design and manufacturing
No full textControllable directional liquid transport, as a promising form of intelligent liquid manipulation, plays an important role in many fields. In nature, directional liquid transport properties are found on a wide variety of biological surfaces, such as the Namib Desert beetle, cactus and Crassula muscosa, etc. Learning from nature provides great inspiration for researchers to solve engineering problems. In this review, the classical directional transport mechanisms, including the wettability gradient and the Laplace pressure difference, are introduced. Then, from single to multiple biomimetic surfaces, the design and manufacturing are reviewed in detail through some representative examples. Finally, some challenges faced in the current development of bioinspired surfaces are summarized.</p
A study on the imobilization method of E. coli for AFM detection under physiological conditions
No full textThe micro-nano manipulation techniques based on Atomic Force Microscopy (AFM) is an important tool for studying the morphology and mechanical properties of bacteria under physiological conditions. However, immobilizing the bacteria on the substrate is the key obstacle for AFM detection in liquid condition. In this study, the methods of embedding and adsorption were combined to improve the immobilization efficiency. Compared to E. coli on a non-structured base surface, E. coli on a structured base surface appears more stretched out and is less likely to aggregate. It grown along the structure of the substrate, achieving nanomanipulation to a certain extent. This study will provide a new immobilization method for microorganism as well as E. coli.</p
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