Decoupling Mechanism Research Articles

A frequency-limited waviness and curvature measurement algorithm for composite fibre trackings

Given a set of irregularly sampled 3D polygonal curves representing composite fibres within a micro-computed tomography volume, a new approach based on the Frenet–Serret formulas is proposed to measure the point curvature and waviness along a polyline even when its oscillations are not coplanar. However, a direct computation of the measures would lead to ill-formed results depending on variant externalities across acquisitions such as noise, sampling, resolution, fractality, etc. Consequentially, we also propose a decoupling mechanism employing a low-pass Gaussian frequency filter to gradually discard features smaller than a certain user-specified σ wavelength referenced in actual space units. This proposal has been tested, characterized and visualized using both real and synthetic datasets contemplating complex waveform features to assess the filter selectivity and convergence across varying sampling frequencies (i.e. polyline resolution). The C++ VTK implementation, alongside an extra amount of supplementary materials encompassing the execution results and synthetic datasets is provided.

Port isolation improvement of full‐duplex single‐patch antenna by loading full‐wave resonators

In this article, a pair of full-wave microstrip resonators is loaded at the nonradiative edges of the patch to improve port isolation of two-port copolarized single-patch antennas (SPAs) for full-duplex applications. First, the decoupling mechanism and its resulting radiation characteristics are exhaustively analyzed, which indicates that more similar radiation patterns and lower crosspolarization can be achieved based on the directly suppressing port coupling. Then, a transversal-section-like topology composed of an additional interference path and the SPA is proposed to realize this purpose. To clearly illustrate the operation principle in practical design, the phase shifts of both paths, that is, the interference paths from Port 1 to Port 2 via the patch and the full-wave resonators, are exhaustively investigated. Attributing to the realization of a stable 180° out of phase between the two paths, the resultant signal is highly and stably attenuated by the interfering signal, and the desired port isolation is satisfactorily attained by manipulating its amplitude readily. The measured results show a dramatic enhancement in isolation between the two ports from 4 to 55 dB with good impedance matching at the two ports. Most importantly, benefiting from the idea of direct port isolation, the radiation performance is hardly deteriorated, with a maximum gain of 8 dBi, beam squint angle of only 10°, and low crosspolarization in the upper half-space.

Tunable quantum gaps to decouple carrier and phonon transport leading to high-performance thermoelectrics

Thermoelectrics enable direct heat-to-electricity transformation, but their performance has so far been restricted by the closely coupled carrier and phonon transport. Here, we demonstrate that the quantum gaps, a class of planar defects characterized by nano-sized potential wells, can decouple carrier and phonon transport by selectively scattering phonons while allowing carriers to pass effectively. We choose the van der Waals gap in GeTe-based materials as a representative example of the quantum gap to illustrate the decoupling mechanism. The nano-sized potential well of the quantum gap in GeTe-based materials is directly visualized by in situ electron holography. Moreover, a more diffused distribution of quantum gaps results in further reduction of lattice thermal conductivity, which leads to a peak ZT of 2.6 at 673 K and an average ZT of 1.6 (323–723 K) in a GeTe system. The quantum gap can also be engineered into other thermoelectrics, which provides a general method for boosting their thermoelectric performance.

Fixed-time control of voltage dynamics of three-phase voltage source inverters with LC output filter

<p>This paper puts forward a fixed-time cascade voltage control system for threephase voltage source inverters (VSIs) with LC output filter.First, a feedforward decoupling mechanism is used to elminate the dependency between the d-q parts of the control system. Then, proportional-integral (PI) regulators are used for current control in the inner loop. The current reference is provided by a novel VSI control technique developed for fixed-time voltage regulation and reference tracking. The approach suggested in this work tracks and maintains the voltage magnitude at its normalized value in a finite-time and before a maximum settling-time fixed in advance and independent of the system’s initial state. The voltage controller also maintains current stability by providing a smoother and smaller current reference. A comparative study with VSI conventional PI control for linear, nonlinear and unbalanced loads confirms the theoretical results.</p>

Design of a Multiloop Control Structure for Load-Disturbance Attenuation and Power-Mismatch Mitigation in Isolated Multiport Power Converters

This article proposes a multiloop control structure for isolated multiport power converters (IMPCs), which includes a multiloop load-disturbance attenuation controller (MLDAC) and also an improved multiloop power-mismatch mitigation controller (MPMMC). The inherent capability of the IMPC to use a common magnetic link (CML) instead of multiple magnetic links offers an attractive solution to design a compact multimodule-based IMPC. With the proposed MLDAC, the IMPC can regulate the system voltage for any load disturbance without requiring any feedforward output current sensor. Moreover, the proposed MPMMC effectively mitigates leakage parameter mismatch and strictly balances the power routing in the multiple ports of the IMPC. The proposed MLDAC and MPMMC are decoupled with an improved decoupling mechanism. Additionally, this article develops a control law to indicate a safe operating area of the MPMMC. The strict voltage regulation of the IMPC under random load disturbance facilitates plug-n-play connectivity and supply of power to pulsed power loads. Moreover, eliminating the power-mismatch issues in the CML ensures equal thermal stresses and duty-life cycles of the solid-state switching devices. The performance of the proposed MLDAC is tested and compared with existing disturbance attenuation techniques. The simulation and the experimental results substantiate the superiority of the proposed MLDAC and MPMMC.

Structural, thermal and superconducting properties of Ag2O-doped YBa2Cu3O7-x composite materials

A composite material with superconducting properties, consisting of YBa2Cu3O7-x doped with Ag2O, was obtained after 233 h of sintering at 960 °C and followed by a special cooling program in oxygen atmosphere. Preferential orientation of YBa2Cu3O7-x (YBCO-123) crystallites was evidenced through X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). Small increase of c parameter for orthorhombic YBCO-123 crystalline unit cell together with a slight decrease of oxygen content (7-x) versus Ag content, were encountered. The dimensions of YBCO-123 crystallites are dependent on Ag content. Thermogravimetric analysis (TGA) during heating in flowing air atmosphere from room temperature (RT) to 1100 °C, showed that total mass loss is depending on Ag content. The cooling (from 1100 °C to RT, in air atmosphere) endows optimal oxygen accumulation only for 0 and 5 wt% Ag, while final masses for 10 and 20 wt% of Ag content, are more than 10% less. Differential scanning calorimetry (DSC) showed peritectic melting points for YBa2Cu3O7-x dependent on Ag percentage. DSC graphics also highlighted the endothermic effects: silver melting; melting and decomposition of Ag2O (in 225.81–345.12 °C temperature range) only for 10 and 20 wt%, but completely missing in the case of 5 wt% Ag content. We concluded that some of Cu sites from YBCO-123 superconductor were substituted by Ag ions. Quasi de Almeida-Thouless lines in the range of magnetic field amplitudes from 0.4 to 800 A/m, in the temperature range from 77 K to RT, were also investigated. Two cases are found concerning intergranular critical currents (Jci): depinning mechanism available for 5 wt% Ag content; the decoupling mechanism for 10, and 20 wt% Ag content.

The Parasite Within: The Evolution of an Innovation Unit

Innovation units in large organizations are often mandated to follow different rules and dynamics than the rest of the organization, resulting in tensions and chaffing relationships. But our understanding about how such units evolve over time and integrate (or not) with the organization is scarce. This paper addresses the question of: How do tensions drive the evolution of an innovation unit and its relationship with the organization? Through a qualitative longitudinal single case study of an innovation unit in a large globally dispersed organization, the study finds that multi-level and reinforcing tensions drive the innovation unit’s evolution as it adopts different charter (culture building, network building and platform building). We derive a process framework showing how tight and loose coupling (and eventually de-coupling) mechanisms shape the relationship between the unit and the organization. This study contributes to the broader literature on organizing and managing innovation in large organizations.

Trajectory distributed receding planning for UAV swarms subject to limited communication distance

For the security and efficiency issues of trajectory planning of unmanned aerial vehicle (UAV) swarms subject to the limited communication distance, this paper establishes the distributed receding planning framework and proposes the local-priority-decoupled sequential convex programming method (LPD-SCP). LPD-SCP divides swarm trajectory planning problems into a series of short-horizon single-UAV convex optimization subproblems, which can improve the computational efficiency and security of trajectories. This paper derives the length of feasible planning horizon to ensure the safety of trajectories. The communication-distance-limited local-priority decoupling mechanism is designed to adjust the priority of UAVs in the neighborhood according to the communication condition for achieving collision avoidance under communication distance limitation. In addition, the trajectory-time-consistency adjustment strategy is customized to realize the flight time consistency of UAVs in the neighborhood by updating the lower boundary constraint of flight time. It is theoretically guaranteed that the proposed LPD-SCP can obtain a swarm trajectory in several receding planning horizons subject to flight constraints. Simulation results demonstrate that LPD-SCP can plan the cooperative trajectories satisfying the flight performance, collision avoidance, and time consistency constraints under communication distance limitation, and the runtime of generating the short-horizon rendezvous trajectories for 15 UAVs is less than 4 s.

Design of a Compact UWB-MIMO Antenna with Isolation Enhancement through Extended Elliptical Ground Plane

This paper deals with the design of a Multiple Input Multiple Output (MIMO) antenna for UWB applications. It is composed of two identical radiating elements (parallel monopoles) symmetrically arranged on a FR-4 substrate. The monopoles are closely spaced (about 0.2 Lambda, center to center). A decoupling mechanism based on vertical extension of the Ground plane with elliptical edges (stub) allows to achieve high isolation (>20 dB). Further, the designed system presents good diversity performance, as the obtained Envelope Correlation Coefficient is less than 0.01. The antenna array is compact (36x30 mm2), with ultra-wide operating frequency range (2.6 to 10.8 GHz). Simulations and measurements demonstrate good agreement. The obtained results make the proposed structure a good candidate for any UWB applications and modern wireless communications systems thanks to its wide frequency band, compactness and performance.

Novel Decoupling Method Based on Coupling Energy Cancellation and its Application in 5G Dual-Polarized High-Isolation Antenna Array

A novel decoupling method by utilizing one <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1\times2$ </tex-math></inline-formula> subarray to provide a pair of phase-reversed coupling paths for coupling energy cancellation is proposed. The newly proposed decoupling approach is implemented by symmetrically loading several U-type, I-type, and cross strips around the antennas to change the original couplings, so that two elements in the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1\times2$ </tex-math></inline-formula> subarray can form a pair of phase-reversed coupling paths into adjacent element in different subarray for coupling cancellation. Then, the couplings from the subarray to adjacent element are effectively suppressed, thus the isolations between different subarrays of the array are promoted. Moreover, the method can be also applied in improving the isolation between different polarizations in the same subarray. In addition, these strips not only have little influence on radiation characteristics of the antenna array, but also can be etched on the antenna layer without extra profile and process. For demonstration, one dual- polarized patch antenna array based on the new decoupling mechanism is designed. The results indicate that all the isolations between the subarrays of the proposed dual-polarized antenna array can achieve a very high level of over 25 dB in an operation band of 3.4–3.6 GHz. Compared with other decoupling methods, the proposed method can simultaneously improve complex multiple-port isolations among different subarrays and different polarizations to realize a very high isolation with less impact on antenna radiation. Due to above features, the proposed decoupling mechanism is expected to find potential applications in 5G dual-polarized multiple-input–multiple-output (MIMO) antenna array.

Supply‐controlled calcium carbonate dissolution decouples the seasonal dissolved oxygen andpHminima in Chesapeake Bay

AbstractAcidification can present a stress on organisms and habitats in estuaries in addition to hypoxia. Although oxygen and pH decreases are generally coupled due to aerobic respiration, pH dynamics may be more complex given the multiple modes of buffering in the carbonate system. We studied the seasonal cycle of dissolved oxygen (DO), pH, dissolved inorganic carbon, total alkalinity, and calcium ion (Ca2+) along the main channel of Chesapeake Bay from May to October in 2016. Contrary to the expected co‐occurrence of seasonal DO and pH declines in subsurface water, we found that the pH decline ended in June while the DO decline continued until August in mid‐Chesapeake Bay. We discovered that aerobic respiration was strong from May to August, but carbonate dissolution was minor in May and June and became substantial in August, which buffered further pH declines and caused the seasonal DO and pH minima mismatch. The rate of calcium carbonate (CaCO3) dissolution was not primarily controlled by the saturation state in bottom water, but was instead likely controlled by the supply of CaCO3particles. The seasonal variability of Ca2+addition in the mid‐bay was connected to Ca2+removal in the upper bay, and the timing of high carbonate dissolution coincided with peak seasonal biomass of upper Bay submerged aquatic vegetation. This study suggests a mechanism for a novel decoupling of DO and pH in estuarine waters associated with CaCO3, but future studies are needed to fully investigate the seasonality of physical transport and cycling of CaCO3.

Decoupling Capability of Levitation Frames for Medium-Low Speed Maglev Trains

Medium-low speed maglev trains (MSMTs) with a levitation gap of only 8–10[Formula: see text]mm need an adequate decoupling capability on the levitation frames to ensure stability control in levitation, while preventing the train from rolling sideways when in landing. Based on the geometric and kinematic relationships, two types of levitation frames are studied, i.e. levitation frame with end-set air spring (LFEAS) and levitation frame with mid-set air spring (LFMAS). For each levitation frame, the decoupling process and mechanism are analyzed, the analytical equations for the kinematic attitude are derived, the decoupling capability under different excitations is calculated, along with the effect of various structural parameters assessed. In addition, a test method is designed for the rolling of the levitation frame, particularly with the anti-rolling capability of the LFMAS measured. The results indicate that oscillation of the hanger rods and anti-rolling beams can compensate for displacement when the motion of the levitation frame is decoupled, which is the key to the decoupling capability. Also, the position of the anti-rolling devices and the length of hanger rods do not affect significantly the decoupling capability. However, a longer anti-rolling beam is more conducive to decoupling, but it does not affect the anti-rolling capacity of the levitation frame. The maximum roll computed of the LFMAS is 2.84[Formula: see text]mm, which meets the anti-rolling requirement.

Decomposing the decoupling of plastics consumption and economic growth in G7 and China: Evidence from 2001 to 2020 based on China's import ban

Plastic recycling is critical for dematerializing of plastics. It has a profound implication on decoupling economic growth from environmental pressure and advancing waste plastic governance domestically and internationally while identifying drivers that might improve decoupling. In this study, plastic consumption and recycling patterns are presented, and the factors influencing the acceleration of dematerialization subsequent to the ban were investigated in the G7 countries and China. The results show that plastic consumption increases from 7.60 million metric tons (mt) to 12.60 mt between 2017 and 2019, and subsequently rapidly decreases to 6.84 mt in 2020. The plastic recycling rate drastically decreased by 21.3% in 2017, and decreased slightly from 2017 to 2020, at an annual rate of 2.9% on average. China's ban shocked the decoupling trends, which showed resilience and motivated the development of robust plastic recycling, and the global recycling transformation pattern accelerated the dematerialization of plastics. Decoupling performances of the G7 and China gradually stabilized in 2019, and all the countries were strongly decoupled in 2020, although decoupling index (DI) fluctuates from 2017 to 2020. Among the recycling-trading drivers, the improvement of waste plastic quality in recycling contributes more to decoupling, the recycling rate shows a more negative decoupling effect on China before the ban, and the population effect is weak relative to other influencing factors. The factors revealed the mechanism of decoupling of plastic consumption in the recycling-trading process, and the recyclability improvement in terms of plastic quality is important for dematerialization.

Decoupling mechanism of heavy metal water pollutant discharge in the Yellow River Basin

The decoupling of economic growth and heavy metal water pollution discharge in the Yellow River Basin is conducive to the coordinated promotion of large-scale governance. Although there are abundant researches on the decoupling elasticity of resource and environment consumption and its driving effect, there are few microscopic analyses on the driving effect. In view of this, Tapio and LMDI model for the Yellow River basin in 2011-2017 economic growth and heavy metal water pollutants decoupling state and driving effect, explain the decoupling mechanism of heavy metal discharge in the Yellow River basin. The results show that : (1) Although there is a strong decoupling state at the basin level (except 2014-2015), the decoupling situation in the upstream region is still very unstable. (2) The sewage discharge intensity effect is the dominant effect driving the discharge decoupling of heavy metal water pollutants in the basin; The income effect of industrialization is the dominant effect of restraining the decoupling of heavy metal water pollutant discharge.

Optimal control and learning for cyber‐physical systems

Optimal control and learning for <scp>cyber‐physical</scp> systems

A Passive Decoupling Mechanism for Misalignment Compensation in Master-Slave Teleoperation

Teleoperated robots are commonly used in minimally invasive surgery as they can control surgical instruments at a distance. An operator sends the motion command via a master console, which must convert these into suitable slave instrument actuator inputs for intuitive interaction. However, most master-slave systems available to date use incremental task-space control and clutching, which introduces a discontinuity and orientation misalignment between the master control handle and slave instrument, with a consequent impact on task performance. In this article, we proposed a new master manipulator design to compensate for misalignment mechanically. The modular gimbal consists of a passive decoupling mechanism and a wrist locking feature. After describing the mechanisms and its kinematic configuration, we report on a comparative study under controlled conditions, developed to measure the end effector orientation in both compensated and non-compensated scenarios. The results demonstrate that the compensated master console maintains a near constant end effector orientation over the workspace during clutching, showing great promise as a solution to this outstanding open challenge in master-slave manipulation.

Disturbance Decoupling and Tracking Controller Design for Lateral Vehicle Dynamics

This paper addresses an augmented nonlinear lateral vehicle and lane keeping dynamics in the presence of some unknown disturbances. In a geometric basin, considering unobservable spaces, their orthogonal complements, and using control invariant properties, a disturbance decoupling mechanism is designed for the mentioned dynamics. Afterward, a nonlinear tracking controller is designed to steer the vehicle on a reference path. The obtained disturbance decoupling and tracking controllers are implemented on a typical passenger car in a simulation environment to demonstrate the effectiveness and performance of the proposed method. It is shown that the controller decouples both the uniformly distributed and exponentially attenuated disturbances from the output.

Anisotropic conductive networks for multidimensional sensing.

In the past decade, flexible physical sensors have attracted great attention due to their wide applications in many emerging areas including health-monitoring, human-machine interfaces, smart robots, and entertainment. However, conventional sensors are typically designed to respond to a specific stimulus or a deformation along only one single axis, while directional tracking and accurate monitoring of complex multi-axis stimuli is more critical in practical applications. Multidimensional sensors with distinguishable signals for simultaneous detection of complex postures and movements in multiple directions are highly demanded for the development of wearable electronics. Recently, many efforts have been devoted to the design and fabrication of multidimensional sensors that are capable of distinguishing stimuli from different directions accurately. Benefiting from their unique decoupling mechanisms, anisotropic architectures have been proved to be promising structures for multidimensional sensing. This review summarizes the present state and advances of the design and preparation strategies for fabricating multidimensional sensors based on anisotropic conducting networks. The fabrication strategies of different anisotropic structures, the working mechanism of various types of multidimensional sensing and their corresponding unique applications are presented and discussed. The potential challenges faced by multidimensional sensors are revealed to provide an insightful outlook for the future development.

Fast weight recovery, metabolic rate adjustment and gene-expression regulation define responses of cold-stressed honey bee brood

In temperate climates, low ambient temperatures in late winter and in spring can result in cold stress conditions in brood areas of weakened honey bee colonies, leading to increased levels of developmental interruptions and death of the brood. Very little is known about the physiological and molecular mechanisms that regulate honey bee brood responses to acute cold-stress. Here, we hypothesized that central regulatory pathways mediated by insulin/insulin-like peptide signalling (IIS) and adipokinetic hormone (AKH) are linked to metabolic changes in cold-stressed honey bee brood. A. mellifera brood reared at suboptimal temperatures showed diminished growth rate and arrested development progress. Notably, cold-stressed brood rapidly recovers the growth in the first 24 h after returning at control rearing temperature, sustained by the induction of compensatory mechanisms. We determined fast changes in the expression of components of IIS and AKH pathways in cold-stressed brood supporting their participation in metabolic events, growth and stress responses. We also showed that metabolic rate keeps high in brood exposed to stress suggesting a role in energy supply for growth and cell repair. Additionally, transcript levels of the uncoupling protein MUP2 were elevated in cold-stressed brood, which could indicate that this protein acts in the heat generation through mitochondrial decoupling mechanisms and/or in the ROS attenuation. Physiological, metabolic and molecular mechanisms that shape the responses to cold-stress in honey bee brood are addressed and discussed.

Integrated linear reactor in transformer based on non-orthogonal decoupling method

The air-core reactor has the advantage of good linearity and low noise, however the problem of large space occupation. Power filter with the air-core reactor is indispensable with the widespread use of the power electronic devices in electrified transportation system and urban distribution system. It is hoped that the air-core reactor can be integrated in the transformer to reduce the space while the good performance of the power filter is kept. In this paper, a non-orthogonal decoupling (NOD) method is proposed, as well as a new design to integrate the linear reactor based on it. Further research including the structure of the integrated linear reactor (ILR) windings, the mechanism of the power decoupling among windings and the calculation of the inductance values are introduced. A 3-D finite-element simulation model is established which demonstrate the correctness of the analysis and provided an assistant approach of engineering design. Finally, the prototype system of the box-type distribution substation with integrated filter reactor and its experimental date are shown, the distribution transformer with integrated air-core reactors are confirmed to have excellent performance.