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Photocatalytic Intramolecular Aminocarboxylation of Alkenes with Atmospheric CO2: Diastereoselective Access to β-Homoproline Derivatives
No full textbeta-Homoproline derivatives are valuable scaffolds in biologically active molecules and pharmaceuticals. However, efficient methods for synthesizing alpha-substituted beta-homoproline derivatives remain underdeveloped. We report a photoredox-catalyzed intramolecular aminocarboxylation of alkenes using atmospheric CO2 under mild conditions. This transformation provides a broad range of alpha-substituted beta-homoprolines in good to excellent yields (up to 93%) and high diastereoselectivity (up to 12:1). The synthetic utility of the products was demonstrated through various downstream transformations.FALSEsciescopu
Anisotropic strain relaxation-induced directional ultrafast carrier dynamics in RuO2 films
No full textUltrafast light-matter interactions inspire potential functionalities in picosecond optoelectronic applications. However, achieving directional carrier dynamics in metals remains challenging due to strong carrier scattering within a multiband environment, typically expected for isotropic carrier relaxation. In this study, we demonstrate epitaxial RuO2/TiO2 (110) heterostructures grown by hybrid molecular beam epitaxy to engineer polarization selectivity of ultrafast light-matter interactions via anisotropic strain engineering. Combining spectroscopic ellipsometry, x-ray absorption spectroscopy, and optical pump-probe spectroscopy, we revealed the strong anisotropic transient optoelectronic response at an excitation energy of 1.58 eV in strain-engineered RuO2/TiO2 (110) heterostructures along both in-plane [001] and [110] crystallographic directions. Theoretical analysis identifies strain-induced modifications in band nesting as the underlying mechanism for enhanced anisotropic carrier relaxation observed at this excitation energy. These findings establish epitaxial strain engineering as a powerful tool for tuning anisotropic optoelectronic responses with near-infrared excitations in metallic systems, paving the way for next-generation polarization-sensitive ultrafast optoelectronic devices.TRUEsciescopu
Sodium cation exchanged zeolites for direct air capture of CO2
No full textDirect air capture technology requires investigating materials that can capture carbon dioxide inexpensively and efficiently, considering their performance under real atmospheric conditions. This study systematically investigated the CO2 adsorption-desorption performance of the representative zeolites (ZSM-5, Beta, Mordenite and Y) in H- and Na-forms using various analytical methods, including in-situ Diffuse Reflectance Infrared Fourier Transform spectroscopy. Compared to the corresponding H-zeolites, the enhancement of CO2 adsorption capacity by Na+ ions was observed for all the structure-type zeolite adsorbents. The Na-ZSM-5 showed excellent performance in the direct air capture of CO2 (DAC) due to its relatively smaller pore size and stronger acid-basic properties. The effective adsorption capacity of Na-ZSM-5 was pronounced at lower Si/Al ratios, making it the most efficient low-concentration CO2 adsorbent. The low silica Na-ZSM-5 exhibited a durable adsorption-desorption capacity after multiple cycles, indicating its practical reusability. When applied to real atmospheric air conditions, this low silica Na-ZSM-5 effectively adsorbed CO2 in the presence of oxygen and moisture, emphasizing its potential for a direct air capture adsorbent. This study provides insights into the properties of zeolites for CO2 capture from air, highlighting their potential as effective DAC sorbents that can be produced on a large scale. © 2024TRUEscopu
Spectrally-coded optical film for independent transmission and reflection on curved surface
No full textEmerging demands for anti-counterfeit security and adaptive camouflage necessitate optical films that conform to the curved transparent substrates of windows, visors, and protective eyewear. These surface-conformal films must deliver high chromatic performance while accommodating geometrical flexibility. Crucially, applications such as hidden displays and directional visual cues require distinct color outputs depending on viewing direction or polarization state. To meet this need, we present a flexible, surface-conformal dual-mode spectral-coded color film (DS-CF) that enables independent control over transmitted and reflected colors. By integrating two resonators within a multilayer thin-film structure, the DS-CF leverages both Lorentzian and Fano-type resonances to realize programmable bi-directional coloration. This design overcomes the limitations of conventional dyes and photonic structures that inherently couple transmission and reflection responses. A painting-inspired demonstration validates the vivid and high-purity color expression in both transmission (approximate to 75%) and reflection (approximate to 41%). Additionally, polarization-sensitive reflectance control is achieved by tailoring the deposition angle of the lossy layer. With scalable fabrication and mechanical flexibility, the DS-CF offers a versatile platform for multifunctional optical films in anti-counterfeit labeling, hidden displays, and adaptive camouflage technologies.FALSEsciescopu
Integrated multi-period distribution network expansion planning with Renewable energy penetration and distributed generation operator profit Kim, Woo-Sop Gwangju Institute of Science and Technology
No full textDriven by intensifying pressures to achieve zero-carbon emissions, Distribution Network Expansion Planning (DNEP) must increasingly reflect changes in energy markets from the Distribution System Operator (DSO) perspective. This study develops a new DNEP model that incorporates renewable energy (RE) penetration targets and explicitly considers DSO profit, integrating policy-driven elements such as grid tariffs and Renewable Portfolio Standards (RPS). Through detailed parameter analysis, including renewable penetration rates, grid tariff structures, and initial investment costs for RE, the research provides actionable insights into strategic decision-making. A key contribution of this work is the formulation of a new DNEP model that directly incorporates RE penetration targets and DSO economic profit. The proposed framework demonstrates how incremental increases in RE penetration determined from governmental policy reports can be integrated into period-based planning, ensuring consistency with national energy transition goals. By simulating various scenarios, the study highlights the importance of adaptive planning to achieve sustainability objectives, maintain DSO financial stability, and accommodate evolving market structures and regulatory mandates. Ultimately, this study offers a valuable tool for DSOs, enabling them to navigate the complexities of renewable integration more effectively. By balancing environmental targets with DSO profitability, the framework supports the development of resilient, economically viable, and policy-aligned distribution networks.MasterAbstract i
Contents ii
List of tables iv
List of figures v
Nomenclature vi
I. INTRODUCTION 1
II. Methodology 4
2. 1. Assumptions of This Paper 4
2. 2. Uncertainty modelling 4
2. 3. Distribution network expansion planning SOCP model formulation 6
2. 3. 1. Structure of DNEP model 6
2. 3. 2. Two-stage stochastic programming model for the DNEP. 8
2. 4. Formulation 9
2. 4. 1. Objective function 9
2. 4. 2. Steady-State Operation of a Radial Distribution System. 11
2. 4. 3. Investment constraints 12
2. 4. 4. Radial constraint 13
2. 4. 5. Distributed Generator (DG) constraints 14
2. 4. 6. Policy-Driven constraint 15
2. 4. 7. Distributed Generator Operator (DGO) constraints 16
III. CASE STUDY 17
3. 1. Target System & Environment 17
3. 2. Simulation Result and Analysis 18
3. 2. 1. Case 1 19
3. 2. 2. Case 2 21
3. 2. 2. Case 3 23
IV. CONCLUSION 24
References 2
Defying Gravity: Towards Gravitoinertial Retargeting of Acceleration for Virtual Vertical Motion in In-Car VR
No full textIn-car VR applications typically synchronize virtual motion with real vehicle movement to minimize visual-vestibular mismatch. However, this approach limits virtual movement to directions in which the vehicle can physically move, typically restricting the experience to horizontal motion. This study introduces a method to expand the range of virtual motion by simulating vertical movement, leveraging vehicle acceleration to induce a vertical pitch illusion via manipulation of gravitoinertial perception. We conducted a two-phase study evaluating (1) optimal vertical gain values for maximizing perceptual realism in a controlled environment and (2) user experience factors such as motion sickness and presence in an on-road VR flight simulation under realistic driving conditions. Our findings show that users tend to prefer vertical gains that exceed theoretically valid mappings, and highlight the importance of aligning virtual motion with perceived inertial cues to enhance the realism and coherence of vertical motion in in-car VR applications. © 2025 IEEE
강화학습 기반 OpenSim 자동 스케일링을 통한인체 운동 분석 정확도 향상 기법
No full textPrecise musculoskeletal scaling is vital for reliable human motion analysis, yet traditional scaling methods are often performed manually, which is time-consuming and expert-dependent. To address these limitations, this study introduces an automatic scaling framework that combines the OpenSim gait2354 model with a Twin Delayed Deep Deterministic Policy Gradient (TD3) reinforcement learning agent. Using 100 static OpenCap trials, subject-specific RL environments were designed and trained with a reward minimizing total errors, RMS, and peak errors. Following over 2,000 episodes, errors significantly reduced: mean total errors from 0.00473 to 0.00168 m² (-64.5%), RMS from 14.7 to 8.8 mm (-40.1%), and peak errors from 27.6 to 15.9 mm (-42.4%). This satisfies OpenSim scaling guidelines (<10 mm RMS, <20 mm peak). The framework can be expanded to diverse anthropometries, effectively automating the scaling process and showing potential for online fine-tuning with new subjects
Numerical demonstration of a switchable binary-state metasurface for the spin hall effect of circularly polarized light
No full textThe spin Hall effect of light, a transverse and spin-dependent splitting at an optical interface, generally depends on the interface properties. By contrast, the spin Hall effect of circularly polarized light is interface-independent, which aids precise nanoscale displacement control. However, the spin Hall-shifted beam generally exhibits low efficiency near normal incidence, where the shift is large. The static nature of metasurfaces with in-plane anisotropy that have been proposed to address this limitation renders them unsuitable for dynamic or reconfigurable applications. In this study, we numerically demonstrated an electrically tunable metasurface that enabled binary-state switching between spin-Hall-shifted and suppressed reflection efficiencies. The metasurface comprised a grating structure and an indium tin oxide layer, whose permittivity was dynamically modulated via an electrical bias, resulting in changes in the reflection amplitude and phase, and thus, in the spin Hall efficiency. Without an applied voltage, the metasurface exhibited suppressed reflection in the spin-Hall-shifted component. By contrast, the dominance switched to spin Hall-shifted reflection upon voltage application. This approach enables the selective control of the spin-dependent reflection intensity without altering the beam displacement, thereby facilitating reconfigurable spin-optical photonic systems.TRUEsciescopu
Development of Adaptive Impedance Control Strategy for an Upper-Limb Cable-Driven Rehabilitation Robot
No full textCable-driven rehabilitation robots (CDRR) offer low inertia and a large workspace, making them well-suited for upper-limb therapy in bedridden patients. Assist-as-Needed (AAN) control promotes neuroplasticity by providing minimal support only when needed, but may not sufficiently challenge users with position-dependent weakness, such as frozen shoulder. To address this, we propose an Assist–Resist Adaptive Control (ARAC) strategy that switches between assistive stiffness and resistive damping, tuning impedance via radial basis functions updated by an adaptive law with forgetting and bias terms. ARAC was implemented on a custom 3-DOF cable-driven planar CDRR with inline load cells and quadratic tension allocation. Eight participants used an elastic fixture to simulate angle-dependent shoulder weakness, which limited their unaided range of motion. Compared to AAN, ARAC significantly increased interaction forces in resistive phases and overall EMG activity, without compromising the full range of motion. These results demonstrate that adaptive control in CDRRs can enable personalized rehabilitation by combining assistance and resistance.Master1. Introduction 1
1.1 Background 1
1.2 Existing Rehabilitation Robot Controls 4
1.3 Research Objectives 6
2 Hardware Setup 9
2.1 Actuation and Sensing Architecture 9
2.2 Motor Configuration 11
2.3 Real-Time Control Framework 13
2.4 Safety and Hardware Integration 15
3 Control Strategy 16
3.1 Low-Level Control 16
3.2 Mid-Level Control 18
3.2.1 Cartesian-to-Cable Tension Mapping 18
3.2.2 Forward Kinematics 19
3.3 High-Level Control 20
3.3.1 Assist-as-Needed: Adaptive Stiffness Learning 20
3.3.2 Resist-as-Needed: Adaptive Damping Learning 23
3.3.3 Assist-Resist Adaptive Control 24
4 Experimental Results 27
4.1 Experimental Setup 27
4.2 Experiment Order 29
4.3 Data Analysis 31
4.4 Results 33
4.4.1 Representative Participant A (Moderate Capability) 33
4.4.2 Representative Participant B (Low Capability) 36
4.4.3 Representative Participant C (High Capability) 38
4.5 Statistical Analysis 40
5 Conclusion 44
5.1 Summary 44
5.2 Contribution 44
References 47
A System Implementation and Validation 51
A.1 Stick-Slip Mitigation 51
A.2 Verification of Interaction Force Measurements 53
A.3 Stiffness Response Analysis 56
B Mathematical Derivations 59
B.1 Conditions for Quadratic Programming 59
B.2 Adaptive Learning Stability 61
C All Participants Results 64
Acknowledgements 6