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In this study, PZT (piezoelectric) actuators and PD control (PDs’ command line tool) method is selected to control the vibration of the flexible manipulator. The dynamic equations of the flexible manipulator system are established based on Lagrange principle. The control strategy of PZT actuators and joint control torque are designed. It is investigated by a Lyapunov approach that a combined scheme of PD feedback and command voltages applies to segmented PZT actuators. By comparison, only PD feedback control is also considered to control the flexible manipulator. The numerical simulations prove that the method of the designed PZT actuators’ control strategy and PD control is effective to compress the vibration of the flexible manipulator.

Water-soluble quantum dots (QDs) have attracted much attention because of their excellent optical stability and biocompatibility. Here we report a simple, easy to operate, safe, and nontoxic method...

The influences of the physical features and chemical properties of activated carbon on Hg0 adsorption were investigated. The textural characteristics of the samples were studied by Brunauer–Emmett–...

A novel gaseous elemental mercury (Hg0) removal agent was successfully synthesized via impregnation method, by using molybdenum trioxide (MoO3) as the active component and carbon aerogel (CA) as the carrier. The as-prepared samples maintained a large specific surface area and excellent pore structure of the pure carbon aerogel, so that MoO3 was better dispersed to obtain enhanced Hg0 removal performance. The maximum efficiency of elemental mercury removal was about 74%, achieved by Mo/C500 sample at 300 °C, while it still had good ability (nearly 60%) in the range of 500–700 °C. The mechanism of mercury oxidation removal was also verified by DFT calculation. This work should help in developing suitable materials for thermocatalytic oxidation of elemental mercury, and also provide some theoretical basis and data support for full-scale application of heavy metal mercury pollution control in coalfired power plants.

The gated photochromic systems have attracted great interest in scientific researches due to their merits in the opto-electronic fields, whereas the multi-stimuli gating function in a unimolecular platform has rarely been addressed. Herein, a new strategy to realize multi-stimuli gated photochromic function was devised relying on a simple Schiff-based diarylethene derivative. The compound shows no photoswitching properties in solution under irradiation with any wavelength of light. It is noteworthy that mecury(II) ions, water and protons can trigger its photo-reactivity independently with different absorption changes, respectively. Therefore, a molecular logic circuit with four inputs, including mecury(II) ions, water, protons and UV light, was fabricated on the basis of the unimolecular platform, suggesting promise for application in multi-controlled photoswitchings. These results could be valuable for the further development of photoswitchings with multiple stimuli responses.

Surface defect defection is a critical task in product quality assurance in industrial production lines. The defect characteristics of surface are easily affected by light. A surface defect detection model based on improved UNet-based neural network, surface defect UNet (S-UNet), is proposed to address the limitations of traditional detection algorithms in surface defect detection, as well as the problems of low accuracy, low precision, and cumbersome detection process. S-UNet uses atrous spatial pyramid pooling (ASPP) to acquire different receptive fields, overcoming the limitations of the UNet model with a single receptive field and improving the ability to segment targets of different sizes. S-UNet utilizes features at different levels to achieve complementary information and improve the coherence and accuracy of segmented areas. The model performs well on small industrial commutator datasets and steel surface defect dataset, reaching the optimal level in terms of precision, recall, and F-score. Compared to UNet and other models, as well as traditional methods, the proposed method achieves better results.

The Cu2+-doped BiOIO3 photocatalyst was prepared by hydrothermal method, with larger specific surface area and enhanced photocatalytic oxidation efficiency of elemental mercury. The crystallinity of the catalyst was affected by the doping ratios of Cu2+. The doping of Cu2+ could make BiOIO3 easier to achieve electron-hole separation and migration and expands the light response range of BiOIO3. The photocatalytic removal of gaseous mercury was used to study the effect of copper ion doping BiOIO3 on the photocatalytic activity of the sample, and the photocatalytic reaction mechanism of Cu2+-doped BiOIO3 was proposed.

LaFeO3 perovskite was synthesized by sol–gel method and calcination method and used to remove mercury in flue gas. Three kinds of metal oxides La2O3, Fe2O3, and LaFeO3 were evaluated. The results indicated that the performances for Hg0 removal decreased in the order of LaFeO3 > Fe2O3 > La2O3. LaFeO3 has ∼94% removal efficiency at 120 ℃. To explore the temperature response range and the influence of simulated flue gas, the performance of LaFeO3 to remove Hg0 under O2, NO, SO2, and different temperature conditions was further examined. Furthermore, LaFeO3 is repeat-ability. The characterization results showed that the Hg0 transition to HgO is due to the valence change of iron and the release of lattice oxygen. In addition, density functional theory (DFT) was conducted to calculate the density of states to verify the performance of the sample. This work shows that LaFeO3 is a promising adsorbent for mercury removal from flue gas in coal-fired power plants.

CuO is an attractive p-type semiconductor due to narrow band gap, low cost, and easy availability. In this paper, we obtained CuO crystals through a simple sol-gel method at room temperature. The samples were proved to be pure CuO crystals through the X-ray diffraction and Raman measurement. The reaction time and OH− concentration played a critical role in the structure and morphologies of pure CuO crystals. Through adjusting of the pH value, several different morphologies, including leaf-like, featheriness structure, and flake-like, were obtained. This paper provided a very simple, low cost and environmentally friendly method to control the morphologies of CuO.

The effective capture or conversion of elemental mercury (Hg0), is the key scientific problem for controlling total mercury pollution in coal-fired power plants. In this work, the cerium chloride (CeCl3) modified carbon aerogel (CA) was successfully synthesized via impregnation method. The as-prepared samples maintained the large specific surface area and excellent pore structure of CA, and the CeCl3 was evenly dispersed, which can play a synergistic role in chemical adsorption and thermal catalysis to capture and oxidize the Hg0 effectively, and the Hg0 removal efficiency was greatly improved, up to 98% at 120 °C. The enhanced Hg0 removal performance could be attributed to the surface active chlorine and cerium oxide (CeO2) particle generated in the preparation process. Based on density functional theory (DFT), the mechanism of mercury removal was discussed in detail. This work would give a new insight for mercury and other heavy metal pollution control in coal-fired power plants.

In this work, Ti3C2, was obtained by selective etching of Al in Ti3AlC2 by hydrofluoric and VS2 was modified on two-dimensional Ti3C2 by solvothermal process to prepare VS2/Ti3C2 composites. In the three-electrode system, the prepared VS2/Ti3C2 composites were compared with VS2 and Ti3C2, respectively, and it was found that the electrochemical properties of VS2/Ti3C2 composites were better. The intercalated VS2 nanosheets expanded the distance between Ti3C2 sheets, leading to a wide ion-accessible surface region and fast ionic/electric transport, resulting in the improved the electrochemical performance of the Ti3C2/VS2 composites. Density functional theory (DFT) analysis shows that the prepared VS2/Ti3C2 composite material has high electrical conductivity. Under the current density of 1 A ∙ g − 1 , the specific capacity of VS2/Ti3C2 composite is 191.3 m A h ∙ g − 1 , which is much higher than that of VS2 and Ti3C2. The asymmetric supercapacitors were assembled with VS2/Ti3C2 composites as positive electrodes, and the electrochemical performance was tested when the power density was 1288 W · k g − 1 and the energy density was 24 Wh · k g − 1 . The initial capacity retention is 82.2% after 5000 cycles of constant current charge and discharge at the current density of 2 A · g − 1 . In short, VS2/Ti3C2 composites show excellent supercapacitor performance in terms of capacity, stability, energy density and power density. It shows that VS2/Ti3C2 is a promising electrode material for supercapacitors.

TiO2/g-C3N4 (TCN) heterojunction photocatalysts with dimensionality tuning was prepared, g-C3N4 successfully shifted from 3D (3DBG) to 2D (2DGN). Compared with 2DGN and TiO2, all the as-prepared heterostructure samples exhibited significantly enhanced photoactivities under light irradiation. Through the photocatalytic mercury removal experiment on samples with different doping ratios, the effect of oxygen species such as hydrocarbons or surface-adsorbing molecular H2O and doping amount on the performance of photocatalytic oxidation were investigated. Finally, the photocatalytic reaction mechanism of charge transfer in the dimensional adjustable Z-scheme heterojunction was proposed. This work provides a new strategy for developing efficient photocatalysts to control mercury.

The tunable photochromic systems have received wide attention in the photoelectronic fields. Herein, we report a diarylethene derivative attached with 2-hydrazylbenzothiazole via Schiff base, which shows the typical photochromic properties upon alternating irradiation with UV and visible light. Remarkably, the varying binding mode and complex strength between the diarylethene and selective metal ions (Cu2+, Ni2+, Cr3+, Sn2+ and Al3+) enable the methanol solution of the diarylethene to exhibit stepwise photochromic reactivity by virtue of these metal ions. The photochromic reactivity of the diarylethene could be suppressed at different levels by the formation of the complex with Cu2+ and Ni2+ in a 2:1 binding mode, respectively, whereas the photochromic reactivity was enhanced to varying degrees by Cr3+, Sn2+ and Al3+ in a 1:1 binding mode. Based on these multiple stimuli responses, a logic circuit with six input signals and three output signals was constructed to perform complex logical operations at the single molecular level.

The morphology of catalyst is a very important factor influencing the photocatalytic activity of the catalyst. Owing to its scientific and technological importance, controllable preparation of photocatalysts with different morphologies has been studied. In this work, BiOIO

A series of flower-like BiOBr with exposed the (0 0 1) and (0 1 0) facets were successfully synthesized by pH adjustment method for gas-phase Hg0 photocatalytic oxidation. The physicochemical properties of the BiOBr were characterized by XRD, SEM, TEM, SAED, XPS, UV–vis DRS, PL, EIS and ESR analysis. It was found that BiOBr with the main exposed (0 1 0) facets exhibited better photocatalytic activity, and its best efficiency reached 65%. This can be attributed to the optimal ratio of dominant (0 1 0) facets exposed by pH adjustment to effectively promote the spatial separation of photo-generated charges. Finally, a possible photocatalytic reaction mechanism was proposed.

A novel particle-nanosheet CeO2/BiOIO3 composites with Ce4+/Ce3+ redox centers and oxygen vacancies were successfully prepared via hydrothermal and calcination schemes. Then the as-prepared samples were analyzed with SEM, TEM, XRD, EPR and other characterizations for the morphology, elemental composition and chemical state. Photocatalytic performance of the CeO2/BiOIO3 composites was evaluated by the removal ability of gas-phase Hg0. It is clearly illustrated that the conjunction of CeO2 with BiOIO3 regulatory band structure effectively reduced the band gap, which can promote the utilization of visible solar light. Furthermore, abundant Ce4+/Ce3+ redox centers and oxygen vacancies on the catalyst surface can promote carrier separation and transfer efficiency. Therefore, combining the above advantages, the best photocatalytic mercury removal efficiency of CeO2/BiOIO3 reached 86.53%, which is 1.3 times higher than that of the pure BiOIO3. Based on the experimental results, the photocatalytic mechanism of CeO2/BiOIO3 heterostructure has been proposed. The catalyst design scheme in this work can provide new ideas for catalyst modification, which can be widely used in solar energy utilization and environmental restoration.

The red water-soluble AgInS2 nanocrsytals (AIS NCs) were synthesized by one-step hydrothermal method. The effects of reaction time and molar ratio of precursors on the bandgap and fluorescence properties of AIS NCs were studied by UV–Vis absorption spectra, photoluminescence (PL) spectra. The experimental results indicated that the fluorescence peak of AIS NCs showed red-shift from 651 nm to 691 nm with the increase of reaction time. The full width at half maximum (FWHW) of AIS NCs obtained at 12 h was very narrow with 18.5 nm. When the reaction temperature and time were set to 200 °C and 12 h, the PL peaks of AIS NCs changed from 696 nm to 670 nm and 735 nm with the increase of indium concentration. In addition, the effect of In concentration on the optical band gap and PL peak was opposite. The optical bandgaps were 1.29 eV, 1.76 eV, and 1.51 eV, respectively. The photocatalytic H2 production performance was studied. The results indicated that the all AIS NCs obtained at different conditions showed high hydrogen production efficiency (>1000 μmol g−1•h−1). Finally, this method is very simple, safe, and easily controlled, and the position of fluorescence peak is adjustable, which shows that AIS NCs obtained in the paper have great application prospects.

The g-C3N4/Bi4O5I2 bionic flower-like structure was facilely synthesized by one step calcination method, and the as-prepared samples were characterized by XRD, UV-vis DRS, photoelectron chemical analysis etc. There obviously exists the phenomenon of a certain right shift for absorption edge of bionic composites according to UV-Vis DRS tests. The mercury removal efficiency of NB-1 (the doping content of g-C3N4 is 1 mmol) can be improved by 76%, which is higher than that of g-C3N4 and Bi4O5I2. Electrochemistry confirms that the bionic structure is beneficial to facilitate the migration efficiency and suppress the surface charge recombination, in turn improve the photocatalytic performance. In addition, the heterostructure between g-C3N4 and Bi4O5I2 are built for efficient modulating the charge transfer channels in the interface/surface to enhance photocatalytic efficiency of Hg0. On the basis of experiment and characterization, a reasonable and convincing mechanism of charge transfer and photocatalytic reaction on Hg0 was proposed.

An amorphous phase TiO2 was fabricated via a fast and simple hydrolysis method and it was characterized with XRD, TEM, BET, UV–Vis, XPS and EPR. The as-prepared amorphous TiO2 has a specific surface area record-breaking 100 times that of crystal TiO2. The results show that the as-samples had better photocatalytic property, which was evaluated for gas-phase Hg0 oxidation under LED light, and photocatalytic efficiency reached up to 40%, which is 1.4 times that of commercial P25. It can be mainly attributed to the large specific surface area of amorphous TiO2 providing more reactive sites and its surface oxygen vacancies as carriers transport channels.

This paper proposes a simple geometrical ray approach to calibrate the extrinsic parameters of the virtual cameras and solve the stereo correspondence problem of the single-lens bi-prism stereovision system. Each images captured using this system can be divided into two sub-images which are generated by two virtual cameras due to the refraction through the bi-prism. This stereovision system is equivalent to the conventional two camera system and the two captured sub-images provide disparity which can be used for depth recovery. The virtual cameras will be calibrated geometrically and the correspondence problem of this system will be solved by applying epipolar geometry constraint on the generated virtual cameras instead of the real CCD camera. Experiments are conducted to validate the proposed method and the results are compared to the conventional approach to confirm its accuracy and effectiveness.

This paper proposes a new method for rectification of single-lens stereovision system with a triprism. The image plane of this camera will capture three different views of the same scene behind the filter in one shot. These three sub-images can be taken as the images captured by three virtual cameras which are generated by the three Face (3F) filter (triprism). A geometry-based method is proposed to determine the pose of virtual cameras and obtain the rotational and translational transformation matrix to real camera. At the same time, the parallelogram rule and refraction rule are employed to determine the desired sketch ray functions. Followed by this, the rectification transformation matrix which applied on the images captured using the system is computed. The approach based on geometry analysis of ray sketching is significantly a simpler implementation: it does not require the usual complicated calibration process. Experimental results are presented to show the effectiveness of the approach.

In the paper, the algorithm of segment-based stereo matching using graph cuts is developed for extracting depth information from the stereo image pairs. The first step of the algorithm employs the mean-shift algorithm to segment the reference image, which ensures our method to correctly estimate in large untextured regions and precisely localize depth boundaries, followed by the use of Adaptive Support Weighted Self-Adaptation dissimilarity algorithm (ASW-SelfAd) for the estimation of initial disparity. This is followed by application of Singular Value Decomposition (SVD) in solving the robust disparity plane fitting. In order to ensure reliable pixel sets for the segment, we filter out outliers which contain occlusion region through three main rules, namely; cross-checking, judging reliable area and disparity distance measurement. Lastly, we apply improved clustering algorithm to merge the neighboring segments. The geometrical relationship of adjacent planes such as parallelism and intersection is employed for determination of whether two planes shall be merged. A new energy function is subsequently formulated with the use of graph cuts for the refinement of the disparity map. Finally, the depth information is extracted from the final disparity map. Experimental results on the Middlebury dataset demonstrate that our approach is effective in improving the state of the art.

Tagged Magnetic Resonance Imaging (MRI) is a noninvasive technique for examining myocardial function and deformation. Tagged MRI can also be used in quasistatic MR elastography to acquire strain maps of other biological soft tissues. Harmonic phase (HARP) provides automatic and rapid analysis of tagged MR images for the quantification and visualization of myocardial strain. We propose a new artifact reduction method in strain maps. Image intensity of the DC component is estimated and subtracted from spatial modulation of magnetization (SPAMM) tagged MR images. DC peak interference in harmonic phase extraction is greatly reduced after DC component subtraction. The proposed method is validated using both simulated and MR acquired tagged images. Strain maps are obtained with better accuracy and smoothness after DC component subtraction.

The objective of this paper is to reconstruct three-dimensional scenes from stereo images. In this paper, the single-lens stereovision system using biprism is employed to capture image pairs. Then, we propose a geometry-based approach to solve stereo rectification problem based on this system. It does not require complex calibration at all and also can obtain accurate extrinsic matrix. Then we propose an algorithm of stereo matching to obtain the disparity map. This method can filter outliers and deal with occlusion. Lastly, we use the algorithm of triangulation to calculate the 3D point cloud from the disparity map and then the final 3D scene is reconstructed. The experimental results show that our proposal methods are feasible and effective.

In the paper, we formulate a new energy function followed by the use of graph cuts to refine the disparity map which takes segment as node. Firstly, the robust disparity plane fitting is modeled and the method of Singular Value Decomposition (SVD) is used to solve least square. In order to ensure reliable pixel sets for the segment, we filter out outliers through three main rules, namely; cross-checking, judging reliable area and measuring the distance between previous disparity to the computed disparity plane. Secondly, we apply improve hierarchical clustering algorithm to merge neighbor. Finally, the final disparity map is obtained. Experimental results demonstrate that our approach is effective in improving the state of the art.

In this paper, we proposed a new method for analyzing the image formation of a prism. The prism was considered as a single optical system composed of some planes. By analyzing each plane individually and then combining them together, we derived a transformation matrix which can express the relationship between an object point and its image by the refraction of a prism. We also explained how to use this matrix for epipolar geometry and three-dimensional point reconstruction. Our method is based on optical geometry and could be used in a multiocular prism. Experimentation results are presented to prove the accuracy of our method is better than former researchers' and is comparable with that of the multicamera stereovision system.

We propose a geometrical approach for virtual camera rectification on uncalibrated single-lens stereovision using a biprism. This system is also called a virtual stereovision system, as the image captured can be divided into two which are equivalent to two images captured using two cameras with different perspectives. The proposed method is divided into two parts. The first part is to compute the projection transformation matrix of two virtual cameras based on a unique geometrical ray sketching, which can accurately recover the extrinsic parameters, and the second part is to compute the rectification transformation matrix, which is applied on the images captured using the system. As the geometrical analysis eliminates the complex calibration process and rectification reduces the correspondence searching to one-dimensional, this method provides a simple stereo matching technique for this system. Experimental results are presented to show the effectiveness of the approach.