Textile‐based electronic techniques that can in real‐time and noncontact detect the respiration rate and respiratory arrest are highly desired for human health monitoring. Yarn‐shaped humidity sensor ...is fabricated based on a sensitive fiber with relatively high specific surface area and abnormal cross‐section. The response and recovery time of the yarn‐shaped humidity sensor is only 3.5 and 4 s, respectively, with little hysteresis, because of the hydrophobic property of these functional fibers and the grooves on the surface of the fibers, which is much faster than those of the commercial polyimide materials. Moreover, a battery‐free LC wireless testing system combined with the yarn‐shaped sensor is fabricated, which is further successfully imbedded into the intelligent mask to detect human breath. Based on the detection of LC wireless testing system, the frequency of 50.25 MHz under the exhaled condition shifts to 50.86 MHz under the inhaled situation of humidity sensor. In essence, the functional yarns with proper structure, would be an excellent candidature to the yarn‐shaped humidity sensor, in which there are good performance and wide application possibilities, eventually offering a facile method for the wireless detection of human physiological signals in the field of electronic fabrics.
A yarn‐shaped humidity sensor is fabricated using sensitive fibers with a relatively high surface area and specific cross‐section. It exhibits an extraordinary humidity sensitivity performance with little hysteresis. A full‐textile wireless and battery‐free humidity sensitive system is then successfully developed for the detection of human physiological signals, i.e., the respiration rate and respiratory arrest.
NiCoAl layered double hydroxide nanosheets.
Display omitted
•Layered double hydroxide nanosheets are prepared by a one-step solvothermal method.•The effects of solvothermal time and Co content on ...structure are investigated.•Al doping improves the electrical conductivity and activity of the electrode.•The assembled asymmetric supercapacitor exhibits excellent cycle performance.
NiCoAl layered double hydroxide nanosheets (NiCoAl-LDHNs) were prepared by a one-step solvothermal method. The shape and size of the obtained nanosheets are optimized by adjusting the solvothermal time and the molar concentration ratio of Ni2+/Co2+ to obtain the electrode material with the best performance. When the solvothermal time is 9 h and the molar concentration ratio of Ni2+/Co2+ is 1:1, NiCoAl-LDHNs has the best morphology and electrochemical performance. When assembled into a supercapacitor, NiCoAl-LDHN-9 has a high specific capacitance of 1228.5 F g−1 at 1 A g−1. As the current density is increased to 20 A g−1, the specific capacitance is 1001.8 F g−1, which still has a high capacitance retention of 81.6%. When NiCoAl-LDHN-9 was assembled into an asymmetric supercapacitor, NiCoAl-LDHN-9//AC has a specific capacitance of 102.1 F g−1 at 0.5 A g−1. The asymmetric supercapacitor devices also show excellent electrochemical performance in terms of energy density (35.9 Wh kg−1 at 225.8 W kg−1), power density (4.8 kW kg−1 at 22.2 Wh kg−1) and cycle life (capacitance retention rate after 10,000 cycles is 87.1%). Those results indicate that NiCoAl-LDHN have the potential to be promising electrode materials for high performance supercapacitors.
Intelligent textile that endow traditional fabric with functionalities have attracted increasing attention. In this research work, we fabricated a flexible and wearable pressure sensor with ...conductive nylon fabric as the electrodes and elastomer Ecoflex as the dielectric layer. The conductive nylon fabric in the twill structure, which showed a high conductivity of 0.268 Ω·cm (specific resistance), was prepared by magnetron sputtering with silver films. The flexible pressure sensor shows a high sensitivity of 0.035 kPa−1, a good linear response under pressure from 0 to 16 kPa, and a quick response time of 0.801 s. The fabricated pressure sensor was found to be highly reproducible and repeatable against repeated mechanical loads for 9500 times, with a small capacitance loss rate of 0.0534. The fabric-based flexible and wearable sensor with good properties can be incorporated into a fabric garment by the hot-pressing method without sacrificing comfort, which can then be used for human motion detecting or touch sensing. The smart glove with finger touch function was proved to be efficient in Morse code editing, which has potential for information transfer in the military field.
Turning insulating silk fibroin materials into conductive ones turns out to be the essential step toward achieving active silk flexible electronics. This work aims to acquire electrically conductive ...biocompatible fibers of regenerated Bombyx mori silk fibroin (SF) materials based on carbon nanotubes (CNTs) templated nucleation reconstruction of silk fibroin networks. The electronical conductivity of the reconstructed mesoscopic functional fibers can be tuned by the density of the incorporated CNTs. It follows that the hybrid fibers experience an abrupt increase in conductivity when exceeding the percolation threshold of CNTs >35 wt%, which leads to the highest conductivity of 638.9 S m−1 among organic‐carbon‐based hybrid fibers, and 8 times higher than the best available materials of the similar types. In addition, the silk‐CNT mesoscopic hybrid materials achieve some new functionalities, i.e., humidity‐responsive conductivity, which is attributed to the coupling of the humidity inducing cyclic contraction of SFs and the conductivity of CNTs. The silk‐CNT materials, as a type of biocompatible electronic functional fibrous material for pressure and electric response humidity sensing, are further fabricated into a smart facial mask to implement respiration condition monitoring for remote diagnosis and medication.
A new conceptual silk meso‐fibrous material for biocompatible electronic applications is developed by carbon nanotubes meso reconstruction. It can be adopted to fabricate various fibrous sensors, i.e., electronic humidity sensors. In combination with internet of things (IoTs) and artificial intelligence technologies, a remote respiratory condition monitoring and diagnosis can be achieved.
Accurate and quick monitoring of an individual's respiration signals plays an important role in health monitoring and disease diagnosis. Electronic fabrics are the best candidates for detecting human ...signals through a non-invasive pathway. Inspired by the potential and attractive applications of fiber-shape electronics in smart and wearable e-textiles, here we developed an all-in-one fibrous capacitive humidity sensor. The fibrous sensor is prepared using a domestic winding fabrication facility and sputtering technique. Analysis of the exact morphology and elemental details of the fibrous sensor was carried out by Fourier transform infrared spectrometry, scanning electron microscopy, and energy dispersive spectrometry. Moreover, the frequency characteristic of the sensor is studied, and exhibits an increasing sensitivity with the decrease of testing frequency. The fabricated humidity sensor exhibited good repeatability and responsiveness performance under the 5 kHz frequency. In addition, the fibrous structure of the sensor makes it appropriate to be integrated into a fabric such as smart mask, which can be used to monitor breathing information and also to provide alarm signals.
In this survey we present a complete landscape of joint object detection and pose estimation methods that use monocular vision. Descriptions of traditional approaches that involve descriptors or ...models and various estimation methods have been provided. These descriptors or models include chordiograms, shape-aware deformable parts model, bag of boundaries, distance transform templates, natural 3D markers and facet features whereas the estimation methods include iterative clustering estimation, probabilistic networks and iterative genetic matching. Hybrid approaches that use handcrafted feature extraction followed by estimation by deep learning methods have been outlined. We have investigated and compared, wherever possible, pure deep learning based approaches (single stage and multi stage) for this problem. Comprehensive details of the various accuracy measures and metrics have been illustrated. For the purpose of giving a clear overview, the characteristics of relevant datasets are discussed. The trends that prevailed from the infancy of this problem until now have also been highlighted.
Highlights
Materials with contradictory performance were prepared using wool keratin (WK).
WK used for in situ preparation of AuNPs and N-doped carbon precursor as well.
Two- and three-electrode ...flexible strip sensors designed for pH and UA detection.
Flexible biosensors with high accuracy and reliable operation in detecting pH and uric acid levels in body fluids are fabricated using well-engineered metal-doped porous carbon as electrode material. The gold nanoparticles@N-doped carbon in situ are prepared using wool keratin as both a novel carbon precursor and a stabilizer. The conducting electrode material is fabricated at 500 °C under customized parameters, which mimics A–B type (two different repeating units) polymeric material and displays excellent deprotonation performance (pH sensitivity). The obtained pH sensor exhibits high pH sensitivity of 57 mV/pH unit and insignificant relative standard deviation of 0.088%. Conversely, the composite carbon material with
sp
2
structure prepared at 700 °C is doped with nitrogen and gold nanoparticles, which exhibits good conductivity and electrocatalytic activity for uric acid oxidation. The uric acid sensor has linear response over a range of 1–150 µM and a limit of detection 0.1 µM. These results will provide new avenues where biological material will be the best start, which can be useful to target contradictory applications through molecular engineering at mesoscale.
Display omitted
► Decahedral PdNPs synthesized using concentrated solar energy in aqueous medium. ► PdNPs solution employed for Suzuki coupling reaction (avoid isolation of PdNPs). ► Reporting lowest ...catalyst loading and highest TOF value for Suzuki reaction. ► The developed protocol was applicable for various derivatives of aryl halides. ► The catalyst works efficiently for three consecutive recycles.
A convenient, mild and cost-effective synthesis of decahedral palladium nanoparticles by exposing aqueous PdCl2 solution to the sunlight in the presence of citric acid as a reducing agent and PVP as a capping agent was reported. Natural solar energy which acts as a driving force for the generation of palladium nanoparticles makes the process attractive and economical. The obtained nanoparticles were thoroughly characterized by using techniques like TEM, SAED, FEG-SEM, XRD and EDAX. It was observed that up to 70% of the palladium nanoparticles have decahedron shape, while remaining 30% consists of all other different shapes. The citric acid helps in shapes selective synthesis, whereas concentrated solar energy supplies dual energy which helps to speed up the reduction process. The aqueous reaction mixture of palladium nanoparticles was directly employed for the Suzuki coupling reaction and hence centrifuging efforts and cost of reagents required for the isolation of nanoparticles were avoided. The synthesized nanoparticles demonstrated excellent catalytic activity in Suzuki coupling reaction of aryl halides with phenyl boronic acid under mild reaction conditions. The methodology is applicable to diverse substrates providing good to excellent yields of desired products. Notably, the obtained yields with lowest catalytic loading resulting in highest TOF (0.05mol% catalyst loading and TOF of 1960h−1) were among the best ever reported for the Suzuki coupling reaction. In addition, the catalyst could be reused for three more consecutive recycles. The effectiveness of present new protocol for the PdNPs synthesis was also compared with PdNPs prepared using conventional heating method.
Silk fibroin (SF) material receives a great deal of attention in the biomedical field for its extensive mechanical performance and applications due to its singular structure/properties and ...applications, especially hierarchical structure. Here, we blended polyethylene glycol (PEG) into SF solutions that reconstruct the hierarchical micro structure of SF. The effect of PEG on the SF gelation process was in situ observed through rheological measurement and optical density changes. The structural change of SF/PEG blended films with different concentrations and their effects on the mechanical performance were investigated. The results indicated that with increasing PEG content, the β-sheet content of the films increased with the α-helix declining, which enables a composite film with a fracture strain exceeding 300%, Young's modulus exceeding 200 MPa and a fracture strength exceeding 20 MPa. The culture of MC-3T3 proves that the film is beneficial for cell proliferation and adhesion. By constructing the mesoscopic structure of SF, the plasticized silk materials provide great options for biodegradable and flexible protein-based materials.
Palladium nanoplates have been synthesized with good shape selectivity by novel and green methodology using concentrated solar. The procedure employs solar energy for the reduction of ionic palladium ...in the presence of PVP and ethylene glycol. The essential slower reduction rate for nanoplates preparation has been obtained by adjusting the concentration ratio of sunlight with PVP. Along with capping effect PVP act as a mild reductant however, ethylene glycol as a reductant and solvent. The obtained nanoparticles consisting ∼70% of hexagonal and triangular nanoplates in the size range of 20–50nm. The obtained PdNPs showing excellent catalytic performance in 2-phenoxy-1,1′-biphenyls and N,N-dimethyl-1,1′-biphenyl derivatives synthesis. The catalyst showing better performance than that of conventionally available 10% Pd/C catalyst. The synthesized nanoparticles could be recycled for three more consecutive recycles.
•Triangular and Hexagonal Pd nanoplates are prepared using concentrated solar energy.•Optimum concentration ratio of sunlight and PVP helps for the nanoplates synthesis.•2-phenoxy-1,1′-biphenyls and N,N-dimethyl-1,1′-biphenyl derivatives are prepared.•One step, heterogeneous, recyclable, ligand free method with low catalyst loading.•The palladium nanoplates shows high TOF value (1940h−1) and recyclability.
Present work aims to develop a greener approach for the palladium nanoplates (PdNPs) synthesis and its catalytic applications. The protocol deals with solar energy assisted ionic palladium reduction in the presence of polyvinylpyrrolidone (PVP) and ethylene glycol (EG) with a good shape selectivity. Polyvinylpyrrolidone plays a duel role of capping agent and mild reductant; whereas, ethylene glycol acts as a reductant and solvent. The optimum sunlight concentration is a key factor to the anticipated nanoplate's synthesis. Results show that the most of nanoparticles are hexagonal and triangular nanoplates in the range of 20–50nm. This is a first report which shows ∼70% selectivity to the nanoplates formation using sun light. The study also covers it's catalytic application, wherein; 2-phenoxy-1,1′-biphenyls and N,N-dimethyl-1,1′-biphenyl derivatives were synthesized by a simple, ligand free, faster, one pot, ecological and economic protocol in aqueous medium. The catalyst shows better performance than that of conventionally available 10% Pd/C catalyst. The prepared PdNPs showed excellent catalytic performance to the desired products with recyclability.
PDF
