Ni/Ni3C Core-Shell Nanochains and Its Magnetic Properties: One-Step Synthesis at low temperature

One-dimensional Ni/Ni3C core-shell nanoball chains with an average diameter by around 30 nm were synthesized by means of a mild chemical solution method using a soft template of trioctylphosphineoxide (TOPO). It was revealed that the uniform Ni nanochains were capped with Ni3C thin shells by about 1 to 4 nm in thickness and each Ni core consists of polygrains. The coercivity of the core-shell nanochains is much enhanced (600 Oe at 5 K) and comparable with single Ni nanowires due to the one-dimensional shape anisotropy. Deriving from the distinctive structure of Ni core and Ni3C shell, this architecture may possess a possible bi-functionality. This unique architecture is also useful for the study on the magnetization reversal mechanism of one-dimensional magnetic nanostructure.Comment: 17 pages, 6 figur

Walking-by-Logic: Signal Temporal Logic-Guided Model Predictive Control for Bipedal Locomotion Resilient to External Perturbations

This study proposes a novel planning framework based on a model predictive control formulation that incorporates signal temporal logic (STL) specifications for task completion guarantees and robustness quantification. This marks the first-ever study to apply STL-guided trajectory optimization for bipedal locomotion push recovery, where the robot experiences unexpected disturbances. Existing recovery strategies often struggle with complex task logic reasoning and locomotion robustness evaluation, making them susceptible to failures caused by inappropriate recovery strategies or insufficient robustness. To address this issue, the STL-guided framework generates optimal and safe recovery trajectories that simultaneously satisfy the task specification and maximize the locomotion robustness. Our framework outperforms a state-of-the-art locomotion controller in a high-fidelity dynamic simulation, especially in scenarios involving crossed-leg maneuvers. Furthermore, it demonstrates versatility in tasks such as locomotion on stepping stones, where the robot must select from a set of disjointed footholds to maneuver successfully

Traditional Chinese Herbal Patch for Short-Term Management of Knee Osteoarthritis: A Randomized, Double-Blind, Placebo-Controlled Trial

Objective. To assess the short-term efficacy and safety of two kinds of Traditional Chinese herbal patches, Fufang Nanxing Zhitong Gao (FNZG) and Shangshi Jietong Gao (SJG), for painful knee osteoarthritis (OA). Methods. Patients were randomly enrolled in a double-blind, placebo-controlled study to receive FNZG (n=60), SJG (n=60), or placebo patch (n=30) for 7 days. Outcome measures included visual analogue scale (VAS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Traditional Chinese Medicine Syndrome Questionnaire (TCMSQ) subscale. Results. Although there was no significant difference among, three groups in short-term pain management, patients receiving FNZG got significant improvement in symptom of fear of coldness as compared with placebo patch (P=0.029). The most common local adverse events of rash, itching, erythema, and slightly damaged skin were observed in 7% of participants. Conclusions. FNZG may be a useful treatment for symptom of knee OA and merits long-term study in broader populations

Fault tolerant operation method of double winding WFSMs system in high power mine equipment

In order to ensure safe and reliable operation of high power mine equipment in fault condition, a fault tolerant operation method of double winding WFSMs system in high power mine equipment was proposed. First, double winding WFSMs mathematical model under two phase rotating coordinate system was set up, and air gap flux was selected as main magnetic field of vector control. Then, mixture gap flux observer of self-switching voltage and current model were built. On this basis, double WFSMs vector control system was designed based on primary and slave parallel drive mechanism, and changing relationship of the WFSMs system models in fault condition was pointed out, then active current correction mechanism was introduced to realize tolerant operation of double winding WFSMs. Finally, 2.5 MW mine hoist industrial field test results show that the proposed method can realize tolerant operation of the system in fault condition, and meanwhile guarantee dynamic and steady state performance of the WFSMs drive system

Facile synthesis of monodisperse Mn3O4 tetragonal nanoparticles and their large-scale assembly into highly regular walls by a simple solution route

The synthesis of high-quality tetragonal Mn₃O₄ nanoparticles and the large-scale assembly of the nanoparticles into highly regularly walls using a simple solution method at low temperature and surfactant-free conditions was carried on. This synthesis route is easily controllable, well-repeatable, mild, and feasible for application to the fabrication of nanopatterns of other materials. Transmission electron microscopy (TEM) and the corresponding selected-area electron diffraction (SAED) pattern show uniform Mn₃O₄ tetragonal nanoparticles. The sharp SAED pattern, which can be obtained from any of the nanoparticles within the nanopatterns and parallel lattice fringes in high-resolution TEM (HRTEM) images, indicates that all of the quantum dots are Mn₃O₄ single crystals aligned along their c axis. The HRTEM images also show a finely dispersed configuration of the nanopatterns

Facile Growth of Caterpillar-like NiCo₂S₄ Nanocrystal Arrays on Nickle Foam for High-Performance Supercapacitors

Ternary cobalt nickel sulfide as a novel and efficient electrode material in supercapacitors has recently gained extensive interests. Herein, we first report a highly conductive caterpillar-like NiCo₂S₄, composed of NiCo₂S₄ nanosheet core and nanowire shell grown on Ni foam via a facile and cost-effective chemical liquid process. Growth mechanism of the NiCo₂S₄ nanosheets@nanowires (NSNWs) structure was also investigated in detail by analyzing time-dependent experimental as well as the amount of additive ammonium fluoride in solution. Furthermore, the electrochemical measurements were performed among three different morphologies of NiCo₂S₄ including nanosheets, nanosheets@nanoparticles, and NSNWs structure, which were obtained from different reaction stages. Because the NSNWs structure has relatively high electroactive surface area, conductivity, and effective electron transport pathways, the as-prepared NiCo₂S₄ NSNWs structure comparing with two other morphologies exhibits the maximum specific capacity of 1777 F/g at 1 A/g and the highest capacitance retention (83% after 3000 cycles) at a high scan rate of 10 A/g with a mass loading density of 4.0 mg/cm². These results indicate that the NiCo₂S₄ NSNWs structure has great potential in supercapacitors

Plasmon-exciton coupling of monolayer MoS2-Ag nanoparticles hybrids for surface catalytic reaction

The optical properties of monolayer molybdenum disulfide (MoS2)/Ag nanoparticle (NP) hybrids and their application to surface catalytic reactions were studied by transmission, photoluminescence (PL) and Raman spectroscopies. The local surface plasmon resonance (LSPR) of Ag nanoparticles was tuned to better match the exciton energy of monolayer MoS2. The PL of the hybrids was enhanced by more than 50 times when the local surface plasmon resonance (LSPR) peak was tuned systematically from 438 nm to 532 nm, indicating a stronger coupling and higher energy transfer rate between the plasmon of the Ag NPs and the excitons of the MoS2. Additionally, photocatalytic reactions of 4-nitrobenzenethiol (4NBT) were performed on the MoS2, the Ag nanoparticles, and the hybrid MoS2 with Ag nanoparticles. On the MoS2 substrate alone, there is no photocatalytic reaction. With a low laser intensity, the probability of a chemical reaction occurring for molecules directly adsorbed onto the Ag NPs is much lower than the probability of a reaction involving those molecules adsorbed onto the MoS2/Ag substrate. At a higher power, although the electric field was reduced by approximately 30% by the MoS2 layer, there is better efficiency for the plasmon-exciton co-driven surface catalytic reactions on the MoS2/Ag substrate compared to the Ag substrate alone. Our findings illustrate the potential to control hot carriers for better surface catalytic reactions by tuning the exciton-plasmon coupling between the 2D transition metal dichalcogenides (TMDCs) and Ag NPs

One-pot synthesis of highly crystallined lambda-MnO2 nanodisks assembled from nanoparticles: Morphology evolutions and phase transitions

Manganese oxides are important materials in many applications. We describe, for the first time, the facile one-pot synthesis of highly crystallined lambda-MnO2 nanodisks assembled from nanoparticles through a novel wet chemical route. Morphology evolutions, magnetic properties, and phase transitions are also studied by transmission electron microscopy, scanning electron rnicroscopy and thermal gravimetric analysis. A mechanism for the formation of the lambda-MnO2 nanodisks as well as their inner structure is proposed based on controlled experiments. The key to the successful preparation of this novel MnO2 nanostructure has been a synergic control of a surfactant, polyvinylpyrrolidone, and a solvent, dimethyl sulfoxide, capable of stabilizing the microreactors and promoting the assembly of manganese nanoparticles