Recent progress towards understanding the mechanism of dynamical tunneling in Hamiltonian systems with three or more degrees of freedom (DoF) is reviewed. In contrast to systems with two degrees of freedom, the three or more degrees of freedom case presents several challenges. Specifically, in higher-dimensional phase spaces, multiple mechanisms for classical transport have significant implications for the evolution of initial quantum states. In this review, the importance of features on the Arnold web, a signature of systems with three or more DoF, to the mechanism of resonance-assisted tunneling is illustrated using select examples. These examples represent relevant models for phenomena such as intramolecular vibrational energy redistribution in isolated molecules and the dynamics of Bose-Einstein condensates trapped in optical lattices.
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http://dx.doi.org/10.3390/e26040333 | DOI Listing |
Rev Sci Instrum
January 2025
Pen-Tung Sah Institute of Micro-Nano Science and Technology, Xiamen University, Xiamen, Fujian 361005, China.
A two-degree-of-freedom bistable energy harvester with a spring-magnet oscillator designed for ultra-low frequency vibration energy harvesting is presented in this paper. It combines magnetic plucking frequency upconversion and a variable potential function to achieve a high-efficiency response while also being suitably installed for applications with spatial limitations. A lumped parameter model of the piezoelectric energy harvester and the magnetic dipoles is applied to develop the theoretical model for the system.
View Article and Find Full Text PDFPalliat Support Care
January 2025
Department of Thanatology and Health Counseling, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan.
Objectives: Supporting family caregivers (FCs) is a critical core function of palliative care. Brief, reliable tools suitable for busy clinical work in Taiwan are needed to assess bereavement risk factors accurately. The aim is to develop and evaluate a brief bereavement scale completed by FCs and applicable to medical staff.
View Article and Find Full Text PDFAnn Vasc Surg
January 2025
Department of Vascular Surgery, Xuanwu Hospital, Capital Medical University, Beijing, China. Electronic address:
Objectives: To compare the safety and efficacy of debulking devices, including directional atherectomy (DA) and excimer laser atherectomy (ELA), when combined with drug-coated balloons (DCB) for treating de novo femoropopliteal atherosclerotic obliterans (ASO). Additionally, to evaluate the long-term outcomes and application status of these different debulking devices.
Methods: Clinical data were collected from patients with femoropopliteal ASO who underwent combined debulking and DCBs at the Vascular Surgery Department of Xuanwu Hospital, Capital Medical University, China, between January 2018 and January 2023.
J Arthroplasty
January 2025
The University of Tennessee Health Science Center-Campbell Clinic Department of Orthopaedic Surgery and Biomedical Engineering, 1400 S. Germantown Rd, Germantown, TN, 38138. Electronic address:
Background: This study investigated the influence of surgical alignment techniques on knee joint biomechanics during stair negotiation tasks. Our hypothesis was that a more personalized joint alignment would result in reduced medial knee loading biomechanics to negotiate the stairs.
Methods: There were 28 adults (14 mechanical alignments [MA], 14 kinematic alignment [KA]) who underwent total knee arthroplasty (TKA) at least one year post-operatively and performed five stair ascent and descent trials at their preferred velocities.
Sensors (Basel)
January 2025
College of Resource Environmental and Safety Engineering, University of South China, Hengyang 421001, China.
To solve the issue of inconvenient and dangerous manual operation during the installation and removal of the main pipe plugging plate in the steam generator in nuclear power plants, a ten-degree-of-freedom plugging robot was designed in the present study that includes a collaborative robotic arm coupled with a servo electric cylinder. By establishing a joint coordinate system for the robot model, a D-H parameter model for the plate plugging robot was established, and the forward and inverse kinematics were solved. The volume level approximate convex decomposition algorithm was used to fit the steam generator model with a convex packet, and an experimental simulation platform was constructed.
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