This article studies the robust trajectory tracking control problem of a quadrotor unmanned aerial vehicle (UAV). In order to guarantee the desired trajectory tracking performance in the presence of ...external disturbances and model uncertainties, the design process of the quadrotor UAV controller is divided into two steps. First, by decomposing the attitude dynamic system into two serial-connected subsystems, a cascade active disturbance rejection control scheme is applied to the attitude subsystem. Second, by introducing an additional high-gain design parameter, a novel backstepping sliding-mode control scheme for position subsystem is constructed. Moreover, the Lyapunov stability analysis is provided to show that the trajectory tracking error can converge to an arbitrarily small residual set. Numerical results illustrate the effectiveness of the designed control method and its robustness to the external disturbances and model uncertainties. Finally, the proposed method is implemented on a quadrotor UAV to demonstrate its feasibility in practical application.
Due to the underwater thermal power system has the characteristic of big parameter variations, strong nonlinearity and other characteristics, it is difficult to achieve variable speed control. In ...this paper, we proposed a new way of stepless speed control of fuel supply, in order to realize precise control of the high-pressure fuel through regulating device, controller, driver and pressure generator. The simulation analysis and experiments showed that this method had rapid response, slight overshoot characters, and could meet the dynamic performance, stability and security requirements.
At nanoscale, man-made materials may show unique properties that differ from bulk and dissolved counterparts. The unique properties of engineered nanomaterials not only impart critical advantages but ...also confer toxicity because of their unwanted interactions with different biological compartments and cellular processes. In this review, we discuss various entry routes of nanomaterials in the human body, their applications in daily life, and the mechanisms underlying their toxicity. We further explore the passage of nanomaterials into air, water, and soil ecosystems, resulting in diverse environmental impacts. Briefly, we probe the available strategies for risk assessment and risk management to assist in reducing the occupational risks of potentially hazardous engineered nanomaterials including the control banding (CB) approach. Moreover, we substantiate the need for uniform guidelines for systematic analysis of nanomaterial toxicity, in silico toxicological investigations, and obligation to ensure the safe disposal of nanowaste to reduce or eliminate untoward environmental and health impacts. At the end, we scrutinize global regulatory trends, hurdles, and efforts to develop better regulatory sciences in the field of nanomedicines.
Understanding hydro‐morphological characteristics in mountain river confluences is significant in flood disaster mitigation and mountain river restoration, which is still poorly explored. This study ...employed a 2D hydro‐morphological model based on the finite element method to simulate the major bed morphological features in a mountainous‐type flume confluence and evaluate the effects of main controlling factors on these features. The modelling results show that the dominant bed morphological features in mountain river confluences can be well produced by the 2D model. Five controlling factors including downstream water level (H), branch discharge ratio (Qr), main channel sediment supply ratio (ψ), tributary slope (St) and confluence angle (α) reflecting different flow‐sediment‐geometry scenarios were adopted into a sensitive study. The upstream reach of the main channel is controlled by H and ψ and their decreases lead to bed degradation. The increase in Qr, St, and α mainly results in bed aggradation and steepening in the tributary, attaining a higher sediment transport rate. This contrasts the existing experimental results, due to the difference in sediment feeding. The size of the bank‐attached bar is promoted by the increase in Qr, St, and α and the decrease in H and ψ. A quantitative analysis shows that the water surface slope well correlates with various dimensions of the scour hole and bar morphology (correlation = 0.58–0.8). Meanwhile, the bank‐attached bar displays a strong self‐similarity (correlation = 0.84–0.98) regarding its geometric dimensions. This study provides new insights into the existing knowledge of the hydro‐sediment‐morphodynamics of mountain river confluences obtained from laboratory studies and field investigations.
The typical bed morphological features in a mountain river confluence can be reproduced by a depth‐averaged hydro‐morphological model. Further numerical assessment explores impacts of different controlling factors associated with hydrodynamics, sediment dynamics and channel geometry on the behaviors of these morphological features.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
It is a great challenge to simultaneously improve the two tangled parameters, open circuit voltage (Voc) and short circuit current density (Jsc) for organic solar cells (OSCs). Herein, such a ...challenge is addressed by a synergistic approach using fine‐tuning molecular backbone and morphology control simultaneously by a simple yet effective side chain modulation on the backbone of an acceptor–donor–acceptor (A–D–A)‐type acceptor. With this, two terthieno3,2‐bthiophene (3TT) based A–D–A‐type acceptors, 3TT‐OCIC with backbone modulation and 3TT‐CIC without such modification, are designed and synthesized. Compared with the controlled molecule 3TT‐CIC, 3TT‐OCIC shows power conversion efficiency (PCE) of 13.13% with improved Voc of 0.69 V and Jsc of 27.58 mA cm−2, corresponding to PCE of 12.15% with Voc of 0.65 V and Jsc of 27.04 mA cm−2 for 3TT‐CIC–based device. Furthermore, with effective near infrared absorption, 3TT‐OCIC is used as the rear subcell acceptor in a tandem device and gave an excellent PCE of 15.72%.
A simple yet effective side chain modulation on the backbone for obtaining both enhanced Voc and Jsc simultaneously is demonstrated in this work. Compared with the controlled molecule 3TT‐CIC, 3TT‐OCIC showed PCE of 13.13% with improved Voc of 0.69 V and Jsc of 27.58 mA cm−2, and the tandem device gives an excellent efficiency of 15.72%.
Full text
Available for:
FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
To explore the effects and molecular mechanism of
on the proliferation, migration and invasion of acute myeloid leukemia (AML) cells.
Bone marrow samples from 35 pediatric AML patients and 35 healthy ...controls in Henan Provincial Children's Hospital from April 2015 to April 2017 and human bone marrow stromal cell lines (HS-5) and AML cell lines (HL-60, THP-1, U-937 and Kasumi-1) were collected. The expressions of
and homeobox A9 (HOXA9) in bone marrow samples and cells were detected by RT-qPCR and Western blot. The Pearson method was used to analyze the correlation of
and
mRNA expression levels in bone marrow samples of AML patients. HL-60 cells were cultured in vitro and divided into 5 groups: Control, si-NC, si-circ-SFMBT2, si-circ-SFMBT2+anti-NC and si-circ-SFMBT2+anti-miR-491-5p, HL-60 cells were transfected with si-NC, si-circ-SFMBT2, anti-NC, and miR-491-5p inhibitor with Lipofectamine™ 3000. RT-qPCR and Western blot were performed to detect the expression levels of
and HOXA9 in cells of each group. The
Purpose/Significance In China, the elderly population is huge, and the degree of aging is obviously accelerating. The gap between urban and rural areas is obvious, with the proportion of the elderly ...population in rural areas being higher than that in urban areas. Along with the accelerating aging process, the health problems faced by the elderly are becoming more and more prominent, and the demand for personal health information literacy will be increasing. Research on health information literacy and health promotion among the elderly, especially the rural elderly, will become an important topic. Therefore, it is important to understand the current situation of health information literacy among rural elderly and explore its influencing factors in order to establish ways and mechanisms to successfully promote health information literacy among rural elderly. Method/Process This paper used a mixed approach combining literature review and quantitative research. Firstly, we formulated a questionnaire and propo
Dissipative self-assembly is common in biological systems, where it serves to maintain a far-from-equilibrium functional state through fuel consumption. Synthetic dissipative systems have been ...prepared that can mimic some of the properties of biological systems, but they often show poor mechanical performance. Here, we report a shear-induced transient hydrogel that is highly stretchable. The system is constructed by adding Cu(II) into the aqueous solution of a pseudopolyrotaxane, which is itself formed by threading molecular tubes on polyethylene glycol chains. Vigorous shaking transforms the solution into a gel, which gradually relaxes back to the sol state over time. This cycle can be repeated at least five times. A mechanism is proposed that relies on a shear-induced transition from intrachain to interchain coordination and subsequent thermal relaxation. The far-from-equilibrium hydrogel is highly stretchable, which is probably due to 'frictional' sliding of the molecular tubes on the polyethylene glycol chains. On shaking, the hydrogel undergoes fast self-healing.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Alzheimer's disease (AD) continues to be a major global health challenge, and the recent approval of Aduhelm and Leqembi has opened new avenues for its treatment. Small‐molecule inhibitors targeting ...Aβ aggregation hold promise as an alternative to monoclonal antibodies. In this study, we evaluated the ability of berbamine hydrochloride (BBMH), a member of the bisbenzylisoquinoline alkaloids, to reduce Aβ aggregation and cytotoxicity. Thioflavin T kinetics, circular dichroism spectroscopy, and atomic force microscopy results indicated that BBMH effectively inhibited Aβ aggregation. Surface plasmon resonance and molecular docking results further revealed that BBMH could bind to Aβ fibrils, thereby hindering the aggregation process. This physical picture has been confirmed in a quantitative way by chemical kinetics analysis, which showed BBMH tends to bind with the fibril ends and thus prevents the transition from protofibrils to mature fibrils as well as the elongation process. Additionally, our MTT results showed that BBMH was able to reduce the cytotoxicity of Aβ40 on N2a cells. Our results demonstrate, for the first time, the potential of BBMH to inhibit Aβ aggregation and cytotoxicity, offering a promising direction for further research and drug development efforts in the fight against Alzheimer's disease.
The inhibitory effects of berbamine hydrochloride (BBMH) on Aβ aggregation were comprehensively evaluated using several widely‐used biophysical assays. Furthermore, the inhibitory mechanisms of BBMH were elucidated through SPR analysis and chemical kinetics analysis. These findings suggest that bisbenzylisoquinoline alkaloids hold great promise in the battle against Alzheimer's disease.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
PDF
