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A novel lead bismuth oxybromide/graphene oxide (PbBiO2Br/GO) composite photocatalyst were prepared using a controlled and nontemplate hydrothermal technique with PbBiO2Br and GO as ...the starting material. The heterojunction photocatalysts were characterized through XRD, FE-SEM-EDS, HR-TEM, XPS, DR-UV–vis, BET, PL, EPR, and UPS. Under the optimal synthesis conditions, the photocatalytic activity of PbBiO2Br/GO composites was much higher than that of PbBiO2Br. Under 25 °C, 1 atm, and 432-nm visible light irradiation at, the optimized PbBiO2Br/GO increased the rate (at 1.913 µmol g−1 h−1) of photocatalytic conversion from carbon dioxide (CO2) to methane (CH4). This conversion rate was higher than that of the original PbBiO2Br material (0.957 µmol g−1 h−1). Therefore, PbBiO2Br/GO is superior for CH4 production and has great potential as CO2 photoreduction catalysts. In addition, such catalytic performance (when using 0.05 wt%-GO/PbBiO2Br composite as a photocatalyst) indicates that the optimal reaction rate constants of crystal violet (CV) and 2-hydroxybenzoic acid (2-HBA) are 0.1278 and 0.0093 h−1, respectively, which are 1.82 and 1.24 times the reaction rate constant of PbBiO2Br as a photocatalyst, respectively. Our findings are useful for PbBiO2Br/GO synthesis and in its future environmental applications, particularly in solar fuel manufacture.
This paper aims to enhance the lateral path tracking control of autonomous vehicles (AV) in the presence of external disturbances. While AV technology has made significant strides, real-world driving ...scenarios often pose challenges such as slippery or uneven roads, which can adversely affect the lateral path tracking control and reduce driving safety and efficiency. Conventional control algorithms struggle to address this issue due to their inability to account for unmodeled uncertainties and external disturbances. To tackle this problem, this paper proposes a novel algorithm that combines robust sliding mode control (SMC) and tube model predictive control (MPC). The proposed algorithm leverages the strengths of both MPC and SMC. Specifically, MPC is used to derive the control law for the nominal system to track the desired trajectory. The error system is then employed to minimize the difference between the actual state and the nominal state. Finally, the sliding surface and reaching law of SMC are utilized to derive an auxiliary tube SMC control law, which helps the actual system keep up with the nominal system and achieve robustness. Experimental results demonstrate that the proposed method outperforms conventional tube MPC, linear quadratic regulator (LQR) algorithms, and MPC in terms of robustness and tracking accuracy, especially in the presence of unmodeled uncertainties and external disturbances.
•Microalgae extracted by microwave using the solvent have the largest extracted of lipid, 30wt.%.•Li4SiO4 is also successfully tested in the transesterification reaction of microalgae oil.•The ...transesterification efficiency by Li4SiO4 could approach 73.5% by the optimal conditions.
Biomass energy is considered as the most potential petroleum substitute in a shorter period of time, for its renewable ability and lower pollution. This research tends to extract algae oil from microalgae with microwave fragmentation technology. This process can reduce the production costs of microalgae biodiesel. The catalysts prepared in different conditions are characterized by BET, XRD and the conversion from the transesterification catalyzed by each catalyst which was determined using GC. Microwave is used for assisting in the lipid extraction of microalgae by solvents in this study. Microwave assists in lipid extraction under various solvents, and the extracting time and power are compared. The experimental results show that microalgae extracted using the solvent has the largest extracted quantity of microalgae lipid, 30wt.%, and the heating performance for transesterification shows that the best conversion is 76.2% under 68°C with the Li4SiO4 amount 3wt.% and the oil/methanol molar ratio 1:18 for 4h.
•This is the first report on a series of BiOxCly/BiOmIn heterojunctions.•The BiOxCly/BiOmIn composition was controlled by adjusting the growth parameters.•The BiOxCly/BiOmIn were indirect ...semiconductors with a 1.78–2.95-eV bandgap.•The new photocatalysts removed CV at a much faster rate than TiO2.•Mechanisms were determined by separating the intermediates using HPLC-MS.
A series of BiOxCly/BiOmIn composites were prepared using autoclave hydrothermal methods. The composition and morphologies of the BiOxCly/BiOmIn composites were controlled by adjusting the experimental conditions: the reaction pH value, temperature, and KCl/KI molar ratio. The products were characterized using X-ray diffraction, scanning electron microscopy-electron dispersive X-ray spectroscopy, UV–vis diffuse reflectance spectroscopy, Brunauer–Emmett–Teller specific surface areas, cathodoluminescence, high-resolution transmission electron microscopy, and high-resolution X-ray photoelectron spectroscopy. The photocatalytic efficiencies of composite powder suspensions were evaluated by monitoring the crystal violet (CV) concentrations. In addition, the quenching effects of various scavengers indicated that the reactive O2− played a major role, and OH or h+ played a minor role in CV degradation. The intermediates formed during the decomposition process were isolated, identified, and characterized using high performance liquid chromatography-photodiode array-electrospray ionization-mass spectrometry to elucidate the CV decomposition mechanism.
We report a colorimetric method for glucose detection based on Au nanoparticle-decorated WSe
2
(Au@WSe
2
) hybrid nanostructures. These hybrid structures are easily synthesized by simply stirring ...HAuCl
4
precursor with WSe
2
nanosheets in aqueous solution. Owing to strong synergistic catalytic effects of Au nanoparticles and WSe
2
nanosheets, the Au@WSe
2
hybrid nanostructures exhibit enhanced peroxidase-like activity (about 2-fold higher compared to WSe
2
nanosheets alone) for 3,3’,5,5’-tetramethylbenzidine oxidation by H
2
O
2
. Based on the highly catalytical property, the colorimetric method for glucose detection is established by coupling glucose oxidase (GOx). The detection limit of glucose is 3.66 µM. Moreover, the proposed colorimetric method is applicable to glucose detection in serum samples and is promising for applications in biomedical fields.
In this study, we synthesized uniform Au nanoparticles (NPs) within the pore channels of Fe3C@NG via a simple chemical method. The resulting Fe3C/Au@NG composite catalyst was characterized, and its ...catalytic performance in the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in aqueous solution under mild conditions was studied. Field emission transmission electron micrograph results revealed uniformly distributed Au NPs inside the pore channels of Fe3C/Au@NG, and this composite catalyst exhibited excellent catalytic performance and good reusability for 4-NP reduction and is easy to synthesize. Therefore, magnetically recoverable Fe3C/Au@NG appears to be a promising catalyst for the reduction of 4-nitrophenol.
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•Fe3C@NG has a mesoporous structure is beneficial to the mass transfer of reactants and products.•Fe3C/Au@NG exhibited excellent catalytic activity for 4-nitrophenol reduction.•Fe3C/Au@NG with good stability can be facilely magnetic separated.
For solving the trajectory tracking problem of the underwater vehicle and manipulator system (UVMS) in the presence of dynamic uncertainties and time-varying external disturbances, this paper ...presents an indirect adaptive control scheme which consists of three parts: an extended Kalman filter (EKF) estimation compensative system, a model-based computed torque controller (CTC), a H∞ robust compensative tracking controller. The contribution of our method is that it can overcome the disadvantages of existing control schemes, which are based on the accurate dynamic model of UVMS, known statistics unmodeled dynamics/external disturbances (e.g., constant or Gaussian), or the accurate, efficient system feedback measurement states by the sensors. According to the Lyapunov stability theorem, it is shown that the proposed indirect adaptive control scheme can guarantee its embedded H∞ robust controller tracking performance for our UVMS. Simulations show that the proposed control scheme can satisfy the design requirements of UVMS in rapid convergence, tracking accuracy, system stability and disturbance attenuation. Therefore, the method presented in this paper can provide a feasible way of controlling the nonlinear UVMS.
•Overcome dynamic uncertainties and time-varying external disturbances of UVMS.•Without known statistics unmodeled dynamics/external disturbances, or the accurate, efficient system feedback measurement states by the sensors.•Guarantee its embedded H∞ robust controller tracking performance for our UVMS.•Rapid convergence, tracking accuracy, system stability and disturbance attenuation.•Provide a feasible way of controlling the nonlinear UVMS.
Underwater vehicle-manipulator system (UVMS) is a commonly used underwater operating equipment. Its control scheme has been the focus of control researchers, as it operates in the presence of lumped ...disturbances, including modelling uncertainties and water disturbances. To address the nonlinear control problem of the UVMS, we propose a robust optimal control approach optimized using grey wolf optimizer (GWO). In this scheme, the nonlinear dynamic model of UVMS is deduced to a linear state-space model in the case of the lumped disturbances. Then, the GWO algorithm is used to optimize the Riccati equation parameters of the Hinfinity controller in order to achieve the Hinfinity performance criterion, such as stability and disturbance rejection. The optimization is performed by evaluating the performance of the closed-loop UVMS in real-time comparison with the popular artificial intelligent algorithms, such as as ant colony algorithm (ACO), genetic algorithm (GA), and particle swarm optimization (PSO), using feedback control from the physical hardware-in-the-loop UVMS platform. This scheme can result in improved Hinfinity control system performance, and it is able to ensure that UVMS has strong robustness to these lumped disturbances. Last, the validity of the proposed scheme can be established, and its performance in overcoming modeling uncertainties and external disturbances can be observed and analyzed by performing the hardware-in-the-loop experiments.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Colon cancer is one of the most life‐threatening malignancies worldwide. Long noncoding RNA (lncRNA) HOX transcript antisense RNA (HOTAIR) is a cancer‐associated biomarker involved in the metastasis ...and prognosis of several cancers. However, whether and how HOTAIR affects colon cancer progression is still unclear. Consequently, we used RNA interference to knock down HOTAIR to explore its effects on human colon cancer cells. The dual luciferase reporter gene assay was initially used for testify the regulating relationship between lncRNA HOTAIR and insulin‐like growth factor 2 mRNA‐binding protein 2 (IGF2BP2). We determined the expressions of HOTAIR, IGF2BP2, E‐cadherin, and vimentin. Meanwhile, cell growth, cycle and apoptosis, migration, and invasion were assayed. LoVo cells were transplanted into nude mice, and tumor formation and microvessel density were evaluated. LncRNA HOTAIR positively regulated IGF2BP2. Besides, the expressions of HOTAIR and E‐cadherin and the apoptosis were increased, while the expressions of IGF2BP2 and vimentin, the growth, invasion and migration of LoVo cells, the average tumor weight, and microvessel density value were decreased. Of importance, overexpressed IGF2BP2 could reverse the above impacts. Taken together, the current study indicates that silencing of HOTAIR could inhibit the invasion, proliferation, and migration, and promote apoptosis of colon cancer LoVo cells through suppressing IGF2BP2 and the epithelial‐mesenchymal transition.
Silencing of HOX transcript antisense RNA (HOTAIR) could inhibit the invasion, proliferation, and migration, and promote apoptosis of colon cancer LoVo cells through suppressing insulin‐like growth factor 2 mRNA‐binding protein 2 (IGF2BP2) and the epithelial‐mesenchymal transition.
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