This paper presents a funnel dynamic surface control combined with fuzzy echo state networks (FESNs) for the prescribed tracking performance of a strict feedback multi-input-multi-output (MIMO) ...nonlinear dynamic system. A new funnel variable is defined so that the funnel virtual control forces the tracking error to fall within funnel boundary, and adaptive FESN method is also proposed to improve the approximation performance in conventional neural network algorithms. A strict feedback controller and adaptive laws for estimating the uncertainties were derived using the recursive steps of dynamic surface control based on the Lyapunov stability theory. Lyapunov stability analysis confirmed the boundedness and convergence of the closed-loop system. The performance of the proposed control scheme was validated by simulations and experimental applications to the tracking control of a MIMO nonlinear system and a robot manipulator.
It has recently been demonstrated that the OER activity of transition metal sulfides (TMSs) could be enhanced by the introduction of a thin amorphous layer on a pristine surface. We report here a ...novel strategy to enhance the OER by developing cobalt nickel sulfide (Co x Ni 1−x S 2 , CNS) with a high density of crystalline and amorphous phase boundaries. Electrochemical activation (ECA) can partially amorphize hollow CNS nanoparticles derived from surface-selective sulfidation. The ECA-treated CNS (ECA-CNS) electrocatalyst, which is comprised of CNS nanodots separated by thin amorphous layers, shows high densities of crystalline and amorphous phase boundaries. This catalyst shows superior OER catalytic performance with a current density of 10 mA cm −2 at a small overpotential of 290 mV, a low Tafel slope of 46 mV dec −1 , a high mass activity of 217 A g −1 , a high turnover frequency of 0.21 s −1 at an overpotential of 340 mV, and excellent stability in alkaline media.
As an extension of the conventional output constraint problem, this paper proposes the use of nonlinear dynamic surface control (DSC) combined with adaptive fuzzy logic control to constrain the ...partial tracking errors of strict feedback nonlinear dynamic systems with uncertainties. Transformation of the tracking errors into new virtual error variables is used to recursively design a DSC controller, and a careful selection of the controller design parameters ensures that partial state tracking errors are confined at all times within the prescribed bounds. The stability and boundedness of all closed-loop signals were confirmed using the Lyapunov theorem. The simulation results highlight the efficacy and utility of the proposed control scheme.
Black anatase TiO2 has surprisingly enhanced solar energy harvesting efficiency and electrical conductivity, which makes it a promising material in a wide range of energy and environmental ...applications. Several experimental and theoretical studies have successfully revealed the mechanisms of band gap reduction by surface hydrogenation of anatase TiO2. However, recent experimental evidence suggests the existence of bulk point defects that yield infrared (∼1.0 eV) photoabsorption and high conductivity of black anatase TiO2. In the current study, using a combination of ab initio molecular dynamics simulations and electronic structure calculations, we successfully explain the physical properties, metallicity, and infrared/microwave absorption (i.e., black color) of highly reduced anatase TiO2 crystal in a hydrogenated state with a newly found pair defect (Tii–VO)4+. Hydrogen atoms in the bulk are unnecessary to understand the observed properties.
This paper presents a dynamic-model-based control scheme for the balancing and velocity control of a unicycle robot. Unicycle robot motion consists of a pitch that is controlled by an in-wheel motor ...and a roll that is controlled by a reaction wheel pendulum. The unicycle robot lacks an actuator for yaw-axis control, which makes the derivation of the dynamics relatively simple although it may limit the motion control. The Euler-Lagrange equation is applied to derive the dynamic equations of the unicycle robot to implement dynamic speed control. To achieve real-time speed control, a sliding-mode control and a nonzero set-point linear quadratic regulator (LQR) are utilized to guarantee stability while maintaining the desired speed-tracking performance. In the roll controller, a sigmoid-function-based sliding-mode controller has been adopted to minimize switching-function chattering. An LQR controller has been implemented for pitch control to drive the unicycle robot to follow the desired velocity trajectory in real time using the state variables of pitch angle, angular velocity, wheel angle, and angular velocity. The control performance of the two control systems using a single dynamic model has been experimentally demonstrated.
An output-tracking-error-constrained dynamic surface control (DSC) is proposed for the robust output positioning of a multiple-input-multiple-output nonlinear dynamic system in the presence of both ...friction and deadzone nonsmooth nonlinearities. An error transformation method and simple barrier Lyapunov function are also proposed to ensure the prescribed output tracking performance and stability without requiring specific observations of the friction and deadzone parameters. In addition, a new adaptive cerebellar model articulation controller-echo state neural networks system is proposed to deal with an unknown nonlinear function to improve the positioning performance. The boundedness of the overall closed-loop signals and the prescribed performance constraints were guaranteed, and precise positioning performance was also ensured regardless of the effects of friction and deadzone. The proposed control scheme was evaluated by simulation and experiment.
Summary
The roles of amorphous phases in photochemical water splitting of semiconductors are still in debate, as the effects of the amorphous phase are largely irregular even in a single material. We ...presumed that the photochemistry of crystal‐amorphous mixed semiconductor systems would be governed by the interface characteristics, and conducted a systematic study to understand the origins of the largely varying photochemical reaction of semiconductors having an amorphous phase. First‐principles calculations on crystalline anatase and amorphous TiO2 showed that the coexistence of crystalline and amorphous TiO2 and the exposure of the phase boundary are advantageous due to the accelerated charge separation by interface dipole moment and the parallelizable oxygen evolution reaction at the boundary. Our computation‐based strategies were demonstrated in our experiments: only the TiO2 nanoparticle and nanotube having partial amorphization on surfaces have highly enhanced photocatalytic water splitting performances (approximately 700%) compared to the pristine and completely amorphized TiO2 systems.
Photocatalytic water splitting activities of c‐a junctioned TiO2 are largely affected by interface electric fields phase boundary exposed to the surface. This work successfully demonstrated two new important factors in the design of photoactive semiconductors: interface electric field and surface parallelization.
Objective
To evaluate predictors of more aggressive disease and the role of multiparametric 3.0‐T magnetic resonance imaging (MRI) in selecting patients with prostate cancer for active surveillance ...(AS).
Patients and Methods
We retrospectively assessed 298 patients with prostate cancer who met the Prostate Cancer Research International: Active Surveillance (PRIAS) criteria, defined as T1c/T2, PSA level of ≤10 ng/mL, PSA density (PSAD) of <0.2 ng/mL2, Gleason score <7, and one or two positive biopsy cores.
All patients underwent preoperative MRI, including T2‐weighted, diffusion‐weighted, and dynamic contrast‐enhanced imaging, as well as radical prostatectomy (RP) between June 2005 and December 2011.
Imaging results were correlated with pathological findings to evaluate the ability of MRI to select patients for AS.
Results
In 35 (11.7%) patients, no discrete cancer was visible on MRI, while in the remaining 263 (88.3%) patients, a discrete cancer was visible. Pathological examination of RP specimens resulted in upstaging (>T2) in 21 (7%) patients, upgrading (Gleason score >6) in 136 (45.6%), and a diagnosis of unfavourable disease in 142 (47.7%) patients.
The 263 patients (88.3%) with visible cancer on imaging were more likely to have their cancer status upgraded (49.8% vs 14.3%) and be diagnosed with unfavourable disease (52.1% vs 14.3%) than the 35 patients (11.7%) with no cancer visible upon imaging, and these differences were statistically significant (P < 0.001 for all).
A visible cancer lesion on MRI, PSAD, and patient age were found to be predictors of unfavourable disease in multivariate analysis.
Conclusion
MRI can predict adverse pathological features and be used to assess the eligibility of patients with prostate cancer for AS.
Lipid accumulation in adipocytes occurs through multifactorial effects such as overnutrition due to unbalanced eating habits, reduced physical activity, and genetic factors. In addition, obesity can ...be intensified by the dis-regulation of various metabolic systems such as differentiation, lipogenesis, lipolysis, and energy metabolism of adipocytes. In this study, the Jeju roasted peel extract from
S.Markov. (JRC), which is discarded as opposed to the pulp of
S.Markov., is commonly consumed to ameliorate obesity. To investigate the anti-obesity effect of JRC, these studies were conducted on differentiated 3T3-L1 cells and in high-fat diet-induced mice, and related methods were used to confirm whether it decreased lipid accumulation in adipocytes. The mechanism of inhibiting obesity by JRC was confirmed through mRNA expression studies. JRC suppressed lipid accumulation in adipocytes and adipose tissue, and significantly improved enzymes such as alanine aminotransferase, aspartate aminotransferase, and gamma-glutamyl transferase and serum lipid profiles. In addition, it effectively modulated the expression of genes related to lipid and energy metabolism in adipose tissue. As a result, these findings suggest that JRC could be a therapeutic regulator of body fat accumulation by significantly alleviating the dis-regulation of intracellular lipid metabolism in adipocytes and by enhancement of energy metabolism (Approval No. CNU IACUC-YB-2023-98).
