In this Letter, we show that a hexagonal boron nitride (h-BN) slot waveguide can achieve strong field enhancement and light confinement in a slot region and a giant gradient force between h-BN slabs. Excellent agreement between simulations and results from an analytical model is observed. In a two-dimensional case, a field enhancement ratio near 60, a power confinement ratio of 80%, and a gradient force over -8.5 nN/μm×mW have been achieved, which are much higher than the slot waveguide based on artificial hyperbolic metamaterials. The gradient force and power confinement ratio in a three-dimensional slot waveguide structure are also studied. A gradient force of -1.2 nN/mW and a power confinement ratio of 50% have been obtained. The h-BN slot waveguide may have potential in particle manipulation.
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http://dx.doi.org/10.1364/OL.41.004991 | DOI Listing |
Sensors (Basel)
December 2024
Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an 710119, China.
During the interaction process of a manipulator executing a grasping task, to ensure no damage to the object, accurate force and position control of the manipulator's end-effector must be concurrently implemented. To address the computationally intensive nature of current hybrid force/position control methods, a variable-parameter impedance control method for manipulators, utilizing a gradient descent method and Radial Basis Function Neural Network (RBFNN), is proposed. This method employs a position-based impedance control structure that integrates iterative learning control principles with a gradient descent method to dynamically adjust impedance parameters.
View Article and Find Full Text PDFSensors (Basel)
December 2024
School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
This study aimed to predict and fit the nonlinear dynamic grip force of the human upper limb using surface electromyographic (sEMG) signals. The research employed a time-series-based neural network, NARX, to establish a mapping relationship between the electromyographic signals of the forearm muscle groups and dynamic grip force. Three-channel electromyographic signal acquisition equipment and a grip force sensor were used to record muscle signals and grip force data of the subjects under specific dynamic force conditions.
View Article and Find Full Text PDFTaiwan J Obstet Gynecol
January 2025
Graduate Institute of Applied Science and Engineering, Fu Jen Catholic University, New Taipei City, Taiwan. Electronic address:
Objective: With an estimated global frequency ranging from5 % to 21 %, polycystic ovary syndrome (PCOS) is one of the most prevalent hormonal disorders. There are many factors found to be related to PCOS. However, most of these researches used traditional methods such as multiple logistic regression (LR).
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Chemistry, Chemical Theory Center, University of Minnesota, Minneapolis, MN 55455-0431.
Multiconfiguration pair-density functional theory (MC-PDFT) was proposed a decade ago, but it is still in the early stage of density functional development. MC-PDFT uses functionals that are called on-top functionals; they depend on the density and the on-top pair density. Most MC-PDFT calculations to date have been unoptimized translations of generalized gradient approximations (GGAs) of Kohn-Sham density functional theory (KS-DFT).
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Global Zero Emission Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 16-1 Onogawa, Tsukuba, Ibaraki 305-8569, Japan.
Recently, ionic thermoelectric supercapacitors have gained attention because of their high open circuit voltages, even for ions that are redox inactive. As a source of open circuit voltage (electromotive force), an asymmetry in electric double layers developed by the adsorption of ions at the electrode surfaces kept at different temperatures has previously been proposed. As another source, the Eastman entropy of transfer, which is related to the Soret coefficient, has been considered.
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