[Research on mode adjustment control strategy of upper limb rehabilitation robot based on fuzzy recognition of interaction force].

In the process of robot-assisted training for upper limb rehabilitation, a passive training strategy is usually used for stroke patients with flaccid paralysis. In order to stimulate the patient's active rehabilitation willingness, the rehabilitation therapist will use the robot-assisted training strategy for patients who gradually have the ability to generate active force. This study proposed a motor function assessment technology for human upper-limb based on fuzzy recognition on interaction force and human-robot interaction control strategy based on assistance-as-needed. A passive training mode based on the calculated torque controller and an assisted training mode combined with the potential energy field were designed, and then the interactive force information collected by the three-dimensional force sensor during the training process was imported into the fuzzy inference system, the degree of active participation σ was proposed, and the corresponding assisted strategy algorithms were designed to realize the adaptive adjustment of the two modes. The significant correlation between the degree of active participation σ and the surface electromyography signals (sEMG) was found through the experiments, and the method had a shorter response time compared to a control strategy that only adjusted the mode through the magnitude of interaction force, making the robot safer during the training process.

Surface Modification of a Lignin-Derived Carbon-Supported Co-Based Metal/Oxide Nanostructure for Alkaline Water Splitting.

Exploring low-cost and eco-friendly bifunctional electrocatalysts of the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline electrolytes is still highly desired, and is crucial for water electrolysis and sustainable hydrogen generation. In this work, we report a facile pyrolysis-oxidation strategy to convert by-product lignin into bifunctional OER/HER electrocatalysts (Co/Co3O4-NPC-400) composed of Co/Co3O4 anchored on N-doped carbon with a surface of rich oxygen vacancies and oxygen-containing groups. The co-pyrolysis of lignin and NH4Cl can achieve a N-doped carbon matrix with a hierarchical pore structure, while the air-annealing process can induce the formation of oxygen-containing groups and oxygen vacancies. Owing to its surface properties, hierarchical pore structure and multiple active components, the constructed Co/Co3O4-NPC-400 possesses bifunctional catalytic activity and superior stability for OER/HER, especially for unexpected OER activity with a high current density of about 320 mA∙cm-2 at a potential of 1.8 V (vs. RHE). Water electrolysis using Co/Co3O4-NPC-400 as both the anode and the cathode needs a cell voltage of 1.95 and 2.5 V to attain about 10 and 400 mA∙cm-2 in 1 M KOH. This work not only provides a general strategy for the preparation of carbon-supported electrocatalysts for water splitting, but also opens up a new avenue for the utilization of lignin.

Fuzzy Adaptive Passive Control Strategy Design for Upper-Limb End-Effector Rehabilitation Robot.

Robot-assisted rehabilitation therapy has been proven to effectively improve upper-limb motor function in stroke patients. However, most current rehabilitation robotic controllers will provide too much assistance force and focus only on the patient's position tracking performance while ignoring the patient's interactive force situation, resulting in the inability to accurately assess the patient's true motor intention and difficulty stimulating the patient's initiative, thus negatively affecting the patient's rehabilitation outcome. Therefore, this paper proposes a fuzzy adaptive passive (FAP) control strategy based on subjects' task performance and impulse. To ensure the safety of subjects, a passive controller based on the potential field is designed to guide and assist patients in their movements, and the stability of the controller is demonstrated in a passive formalism. Then, using the subject's task performance and impulse as evaluation indicators, fuzzy logic rules were designed and used as an evaluation algorithm to quantitively assess the subject's motor ability and to adaptively modify the stiffness coefficient of the potential field and thus change the magnitude of the assistance force to stimulate the subject's initiative. Through experiments, this control strategy has been shown to not only improve the subject's initiative during the training process and ensure their safety during training but also enhance the subject's motor learning ability.

Double-function enhancement algorithm for low-illumination images based on retinex theory.

In order to solve the problems of noise amplification and excessive enhancement caused by low contrast and uneven illumination in the process of low-illumination image enhancement, a high-quality image enhancement algorithm is proposed in this paper. First, the total-variation model is used to obtain the smoothed V- and S-channel images, and the adaptive gamma transform is used to enhance the details of the smoothed V-channel image. Then, on this basis, the improved multi-scale retinex algorithms based on the logarithmic function and on the hyperbolic tangent function, respectively, are used to obtain different V-channel enhanced images, and the two images are fused according to the local intensity amplitude of the images. Finally, the three-dimensional gamma function is used to correct the fused image, and then adjust the image saturation. A lightness-order-error (LOE) approach is used to measure the naturalness of the enhanced image. The experimental results show that compared with other classical algorithms, the LOE value of the proposed algorithm can be reduced by 79.95% at most. Compared with other state-of-the-art algorithms, the LOE value can be reduced by 53.43% at most. Compared with some algorithms based on deep learning, the LOE value can be reduced by 52.13% at most. The algorithm proposed in this paper can effectively reduce image noise, retain image details, avoid excessive image enhancement, and obtain a better visual effect while ensuring the enhancement effect.

Investigation on pore structure regulation of activated carbon derived from sargassum and its application in supercapacitor.

In order to realize the effective regulation of the pore structure of activated carbon and optimize its pore structure properties as electrode material, the effects of activation temperature, activation time and impregnation ratio on the specific surface area, total pore volume and average pore diameter of activated carbon prepared by sargassum are studied by orthogonal experiment. In addition, the electrochemical properties of sargassum-based activated carbon (SAC) and the relationship between the gravimetric capacitance and specific surface area of SAC are also studied. The SACs prepared under all conditions have high specific surface area (≥ 2227 m2 g-1) and developed pore structure, in which the pore diameter of micropores mainly concentrated in 0.4 ~ 0.8 nm, the pore diameter of mesopores mainly concentrated in 3 ~ 4 nm, and the number of micropores is far more than that of mesopores. In the activation process, the impregnation ratio has the greatest effect on the specific surface area of SAC, the activation temperature and impregnation ratio have significant effect on the total pore volume of SAC, and the regulation of the average pore diameter of SAC is mainly realized by adjusting the activation temperature. The SACs exhibit typical electric double layer capacitance performances on supercapacitors, delivering superior gravimetric capacitance of 237.3 F g-1 in 6 mol L-1 KOH electrolyte system at current density of 0.5 A g-1 and excellent cycling stability of capacitance retention of 92% after 10,000 cycles. A good linear relationship between gravimetric capacitance and specific surface area of SAC is observed.

Engineering Sulfur Vacancies in Spinel-Phase Co3S4 for Effective Electrocatalysis of the Oxygen Evolution Reaction.

Restricted by the sluggish kinetics of the oxygen evolution reaction (OER), efficient OER catalysis remains a challenge. Here, a facile strategy was proposed to prepare a hollow dodecahedron constructed by vacancy-rich spinel Co3S4 nanoparticles in a self-generated H2S atmosphere of thiourea. The morphology, composition, and electronic structure, especially the sulfur vacancy, of the cobalt sulfides can be regulated by the dose of thiourea. Benefitting from the H2S atmosphere, the anion exchange process and vacancy introduction can be accomplished simultaneously. The resulting catalyst exhibits excellent catalytic activity for the OER with a low overpotential of 270 mV to reach a current density of 10 mA cm-2 and a small Tafel slope of 59 mV dec-1. Combined with various characterizations and electrochemical tests, the as-proposed defect engineering method could delocalize cobalt neighboring electrons and expose more Co2+ sites in spinel Co3S4, which lowers the charge transfer resistance and facilitates the formation of Co3+ active sites during the preactivation process. This work paves a new way for the rational design of vacancy-enriched transition metal-based catalysts toward an efficient OER.

Esterification catalyzed by an efficient solid acid synthesized from PTSA and UiO-66(Zr) for biodiesel production.

p-Toluenesulfonic acid (PTSA) is a typical homogeneous acid for biodiesel production. Due to the shortcomings of high deliquescence and non-recyclability, it is necessary to synthesize a recyclable solid acid. For the sake of this, UiO-66(Zr) is used to support PTSA through defect coordination, and four different preparation routes are compared. The obtained catalyst (UiO-G) is characterized with thermogravimetry analysis (TG), X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), pyridine FTIR spectroscopy (py-FTIR), nitrogen adsorption-desorption, and base titration. In addition, the effects of esterification parameters on conversion are investigated to obtain the optimal conditions. To further verify the high catalytic activity of UiO-G, the kinetic model of solid-liquid-liquid esterification is established, in which the kinetic parameters of activation energy, reaction order, and exponential factor are calculated. Results indicate the PTSA is successfully inserted in UiO-66(Zr) without destroying its original structure. With that, the maximum conversion of oleic acid to biodiesel of 91.3% is achieved with a molar ratio of methanol/oleic acid of 12 and a catalyst amount of 8 wt% at 70 °C for 2 h. Moreover, UiO-G could remarkably reduce the activation energy, where the activation energy is 28.61 kJ mol-1, the average reaction order is 1.51, and the pre-exponential factor is 29.11 min-1.

Ultralow Ru-Induced Bimetal Electrocatalysts with a Ru-Enriched and Mixed-Valence Surface Anchored on a Hollow Carbon Matrix for Oxygen Reduction and Water Splitting.

Rational design of trifunctional electrocatalysts with robust efficiency used for oxygen reduction, oxygen evolution, and hydrogen evolution reactions (ORR, OER, and HER) is of significance to renewable energy conversion techniques, which remains a challenging issue. This study integrates dominant Co/Co3O4 with a small fraction of RuO2 and the CoRu alloy anchored on a hollow carbon matrix, originating from the novel Ru-doped hollow metal-organic framework (MOF) precursor, which is synthesized via tannic etching and ion exchange. Notably, the introduced ultralow Ru (1.28 wt %) not only generates new Ru-based species but also induces a Ru-enriched surface with abundant oxygen vacancies. Moreover, a suitable balance among different valencies of Co or Ru can be tuned by oxidation time, resulting in preferable Co2+ and Ru4+ species. Triggered by these unparalleled surface properties along with good conductivity, hollow structure, and the synergistic effect of multiple active sites, the resulting CoRu-O/A@hollow nitrogen-doped carbon (HNC) shows robust catalytic performance for ORR/OER/HER in an alkaline electrolyte. Typically, it exhibits a potential gap of 0.662 V for OER/ORR and enables an alkaline water electrolyzer with a cell voltage of 1.558 V at 10 mA cm-2. This work would serve as guidance for well construction of transition-metal-based trifunctional electrocatalysts by the MOF-assisted strategy or the modulation effects of low-content Ru.

Differential temperature control in heat-integrated pressure-swing distillation for separating azeotropes to deal with operating pressure fluctuations: Basic and explanatory data.

This data article contains basic and explanatory data of "Differential temperature control in heat-integrated pressure-swing distillation for separating azeotropes to deal with operating pressure fluctuations" [1], including thermodynamic models, vapor-liquid equilibrium diagrams, steady-state flowsheets, temperature profiles of columns, description and setpoint units of the abbreviation of inventory control loops, description of control loops of control flowsheet with DTC, control flowsheets of PCTC and DTC, temperature and composition tuning constants, faceplates and flowsheet equations, dynamic performances and integral absolute errors. It also contains other important information.

Facile in situ reductive synthesis of both nitrogen deficient and protonated g-C3N4 nanosheets for the synergistic enhancement of visible-light H2 evolution.

A new strategy is reported here to synthesize both nitrogen deficient and protonated graphitic carbon nitride (g-C3N4) nanosheets by the conjoint use of NH4Cl as a dynamic gas template together with hypophosphorous acid (H3PO2) as a doping agent. The NH4Cl treatment allows for the scalable production of protonated g-C3N4 nanosheets. With the corresponding co-addition of H3PO2, nitrogen vacancies, accompanied by both additional protons and interstitially-doped phosphorus, are introduced into the g-C3N4 framework, and the electronic bandgap of g-C3N4 nanosheets as well as their optical properties and hydrogen-production performance can be precisely tuned by careful adjustment of the H3PO2 treatment. This conjoint approach thereby results in improved visible-light absorption, enhanced charge-carrier separation and a high H2 evolution rate of 881.7 µmol h-1 achieved over the H3PO2 doped g-C3N4 nanosheets with a corresponding apparent quantum yield (AQY) of 40.4% (at 420 nm). We illustrate that the synergistic H3PO2 doping modifies the layered g-C3N4 materials by introducing nitrogen vacancies as well as protonating them, leading to significant photocatalytic H2 evolution enhancements, while the g-C3N4 materials doped with phosphoric acid (H3PO4) are simply protonated further, revealing the varied doping effects of phosphorus having different (but accessible) valence states.

Compact general interference hybrid-plasmonic multimode interferometers used for optical hybrid.

We propose three general interference multimode interferometers (MMIs) based on hybrid plasmonic waveguides (HPWs). Among them, the general 2×2 and 4×4 MMIs are designed for a 90° optical hybrid, while the 3×3 MMI is for a 120° optical hybrid. First, by considering the mode interference characteristics inside the multimode HPWs, a compromise between the number of guided modes and the device length is obtained at a determined height of the SiO2 interlayer of the HPW. Also, by analyzing the characteristics of multimode propagation in the HPW-MMI, it is found that the optimal positions of self-images would shift from their theoretical ones. In addition, tapered HPW sections are implemented to improve the coupling efficiencies for lights coupled into/out of the multimode section. Therefore, by optimizing the width and length of the multimode section, and especially the position of the input and output single-mode waveguides, the appropriate structure parameters of three HPW-MMIs are obtained, where the footprints of the 2×2, 3×3, and 4×4 HPW-MMIs are only 1.96×5.4 µm2, 2.18×12.0 µm2, and 2.52×11.5 µm2, respectively. The simulation results show that, at the wavelength of 1550 nm, the 2×2 HPW-MMI exhibits a transmission of 75.6%, a maximum transmissions imbalance of 0.55 dB, and a phase error of 3.68°; the 3×3 HPW-MMI exhibits a transmission of 69.2%, a maximum transmissions imbalance of 0.43 dB, and a phase error of 4.66°; and the 4×4 HPW-MMI exhibits a transmission of 68.5%, a maximum transmissions imbalance of 0.91 dB, and a phase error of 4.81°. All these performances meet the standard industry requirements.

3D interconnected hierarchical porous N-doped carbon constructed by flake-like nanostructure with Fe/Fe3C for efficient oxygen reduction reaction and supercapacitor.

Hierarchical porous N-doped carbon with Fe/Fe3C nanoparticles, high content of N dopants (10.51 wt%), and a 3D interconnected porous architecture constructed by flake-like nanostructure was facilely prepared by carbonization of a zeolitic imidazolate framework-8 (ZIF-8) as a self-sacrificing template and potassium ferricyanide (PF) as a multifunctional iron precursor. The unique porous structure can offer a continuous pathway for electron transfer and shorten the mass transfer pathway, which contribute to both an oxygen reduction reaction (ORR) and a supercapacitor. The influence of the carbonization temperature and iron content on the performance of ORR and supercapacitor was investigated. The as-prepared composites carbonized at 800 °C (Fe-CZIF-800-10) displayed comparable ORR activity with Pt/C in alkaline media as well as excellent long-term stability, superb methanol tolerance, and appreciable onset potential in acid media. Moreover, Fe-CZIF-800-10 exhibited excellent capacity of 246 F g-1 at a current density of 0.5 A g-1 and stability in 6 M KOH. This report provides a facile approach to prepare hierarchical porous Fe/N-doped carbon as a promising electrode material for both fuel cell and supercapacitor applications.

Suppression of the NF­κB signaling pathway in colon cancer cells by the natural compound Riccardin D from Dumortierahirsute.

Colorectal cancer (CRC) is a major cause of mortality and morbidity. Chronic inflammation is closely associated with the development, progression and prognosis of the majority of intestinal malignancies. In recent years, targeting the nuclear factor (NF)­κB signaling pathway for CRC therapy has become an attractive strategy. Riccardin D, a novel macrocyclicbis (bibenzyl) compound, was isolated from the Chinese liverwort plant. Previous studies have suggested that Riccardin D exerted chemo­preventative effects against the intestinal malignancy formation. In the present study, cell counting kit­8, Hochest 33258 staining, mitochondria membrane permeability assay, western blotting analysis, reverse transcription­polymerase chain reaction, luciferase reporter gene assay and molecular modeling analysis were performed to detect the effect and mechanisms of Riccardin D on human colon cancer cells. The results demonstrated that Riccardin D significantly inhibited the growth of HT­29 cells. In addition, the cDNA expression of cyclooxygenase­2, and the protein expression and activity of NF­κB and tumor necrosis factor­α were downregulated; however, the protein expression of cleaved caspase­3 and ­9, and cleaved poly (adenosine diphosphate­ribose) polymerase, and the B­cell lymphoma (Bcl)­2: Bcl­2­associated X protein ratio were upregulated. Furthermore, Auto Dock analysis identified binding sites between Riccardin D and NF­κB. These results indicated that Riccardin D may inhibit cell proliferation and induce apoptosis in HT­29 cells, which may be associated with the blocking of the NF­κB signaling pathway. Thus, Riccardin D should be investigated as an NF­κB inhibitor in cancer therapy.

[A compression algorithm for multi-spectral TDICCD image].

In order to solve the problem of edge and texture blurring of multi-spectral image caused by the wavelet transform and bit-plane encoder of traditional method not taking into account image characteristics, a compression algorithm of multi-spectral TDICCD image having few bands is proposed in the present paper. The proposed direction-adaptive lifting DWT can adaptively choose the best lifting direction and use the Lagrange interpolation technique to make prediction according to its local characteristics. This method makes good use of the image texture features. The proposed rate control algorithm can adaptively allocate the rate bits according to image content. The experiments results showed that the proposed compression algorithm has good compressive property. Compared with traditional approaches, the performance of our method corresponds to the conventional approach for smooth images. However, it was superior to others for images with rich texture and a large number of edge detail information. In the compression ration 4 : 1, the average peak signal to noise ratio of the proposed compression algorithmcould improve the average PSNR by 1.939 dB. They effectively protect the edge and texture detail information for multi-spectral image. It is very suitable for the application of space multi-spectral CCD image with rich texture and a large number of edge detail information.

[Lossless compression of hyperspectral image for space-borne application].

In order to resolve the difficulty in hardware implementation, lower compression ratio and time consuming for the whole hyperspectral image lossless compression algorithm based on the prediction, transform, vector quantization and their combination, a hyperspectral image lossless compression algorithm for space-borne application was proposed in the present paper. Firstly, intra-band prediction is used only for the first image along the spectral line using a median predictor. And inter- band prediction is applied to other band images. A two-step and bidirectional prediction algorithm is proposed for the inter-band prediction. In the first step prediction, a bidirectional and second order predictor proposed is used to obtain a prediction reference value. And a improved LUT prediction algorithm proposed is used to obtain four values of LUT prediction. Then the final prediction is obtained through comparison between them and the prediction reference. Finally, the verification experiments for the compression algorithm proposed using compression system test equipment of XX-X space hyperspectral camera were carried out. The experiment results showed that compression system can be fast and stable work. The average compression ratio reached 3.05 bpp. Compared with traditional approaches, the proposed method could improve the average compression ratio by 0.14-2.94 bpp. They effectively improve the lossless compression ratio and solve the difficulty of hardware implementation of the whole wavelet-based compression scheme.

[Application of ADV212 to the large field of view multi-spectral TDICCD space camera].

In order to resolve the difficult to hardware implementation of the whole vector quantization-based, predictive coding-based and transform coding-based compression scheme caused by the large volume of data, small spectral redundancy and line frequency variability etc. in multi-spectral space camera, an image compression scheme based on ADV212 was proposed in space camera. Firstly, custom-specific mode was presented based on the working principle of adv212 and CCD image properties. In the Custom-specific mode, an ADV212 is able to compress 8 channel CCD data by proposed image frame and interrupt processing strategy using pipelining. Then, this paper analyses the two parameters which affect the quality of image compression. A (10, 5) setting the quantization step method was proposed, This method makes the rate control error reduces 16.385%. Finally, the verification experiments to ADV212 compression system using ground test equipment were carried out. The experiments results showed that compression system can be fast and stable work. All PSNR were more than 30 dB in the compression ratio of 2:1 to 32:1. Compared with traditional approaches, the proposed method could improve the average PSNR by 2.49 dB in the lossy compression mode when the compression ratio is 1bpp. They effectively solve the difficult of hardware implementation of the whole wavelet-based compression scheme.

Ligustrazine derivatives. Part 5: design, synthesis and biological evaluation of novel ligustrazinyloxy-cinnamic acid derivatives as potent cardiovascular agents.

A series of novel ligustrazinyloxy-cinnamic acid derivatives were designed, synthesized and evaluated for their inhibitory effect on adenosine diphosphate (ADP)-induced platelet aggregation in vitro, and also assayed for their protective effect against hydrogen peroxide (H(2)O(2))-induced oxidative damage on ECV-304 cells. Some compounds exhibited high activity in one or both of the assays, of which, compound 2e displayed the highest protective effect on the proliferation of the damaged ECV-304 cells (EC(50) = 0.020 mM), and compound 2f was the most active anti-platelet aggregation agent (EC(50) = 0.054 mM). Structure-activity relationships were briefly discussed.