Flexible pressure sensors are attracting great interest from researchers and are widely applied in various new electronic equipment because of their distinct characteristics with high flexibility, ...high sensitivity, and light weight; examples include electronic skin (E-skin) and wearable flexible sensing devices. This review summarizes the research progress of flexible pressure sensors, including three kinds of transduction mechanisms and their respective research developments, and applications in the fields of E-skin and wearable devices. Furthermore, the challenges and development trends of E-skin and wearable flexible sensors are also briefly discussed. Challenges of developing high extensibility, high sensitivity, and flexible multi-function equipment still exist at present. Exploring new sensing mechanisms, seeking new functional materials, and developing novel integration technology of flexible devices will be the key directions in the sensors field in future.
Ferroferric oxide（Fe3O4） magnetic nanoparticles are widely used as passive targeting carriers in gene therapy, due to their simple preparation, targeting under external magnetic field and easy ...surface grafting. This study synthesized oil phase Fe3O4 nanoparticles with controllable particle sizes in the range from 4 to 9 nm by regulating the accumulation growth time in the solvothermal method. Then, meso-2, 3-dimercaptosuccinic（DMSA）was employed to double exchange oleic acid molecules on its surface to provide good water dispersibility. Finally,Fe3O4-DMSA-PEI magnetic nanoparticles were obtained by grafting branched polyethylenimine（PEI） onto Fe3O4-DMSA surface through amidization reaction. The results demonstrate that the Fe3O4-DMSA-PEI magnetic nanoparticles have a surface Zeta potential of（52.50 ± 1.94） mV, remaining a certain degree of superparamagnetism（14.48 emu/g, 1 emu/g=1 A·m2/kg）. When the mass ratio of Fe3O4-DMSA-PEI magnetic nanoparticles to plasmid DNA is 15 : 1, it can completely block DNA and it
Flexible Temperature Sensors Liu, Ruping; He, Liang; Cao, Meijuan ...
Frontiers in chemistry,
09/2021, Volume:
9
Journal Article
Peer reviewed
Open access
Temperature reflects the balance between production and dissipate of heat. Flexible temperature sensors are primary sensors used for temperature monitoring. To obtain real-time and accurate ...information of temperature, different flexible temperature sensors are developed according to the principle of flexible resistance temperature detector (FRTC), flexible thermocouple, flexible thermistor and flexible thermochromic, showing great potential in energy conversion and storage. In order to obtain high integration and multifunction, various flexible temperature sensors are studied and optimized, including active-matrix flexible temperature sensor, self-powered flexible temperature sensor, self-healing flexible temperature sensor and self-cleaning flexible temperature sensor. This review focuses on the structure, material, fabrication and performance of flexible temperature sensors. Also, some typical applications of flexible temperature sensors are discussed and summarized.
Gelatin was widely used as scaffold materials in 3D bio-printing due to its excellent bioactivity and availability and especially that their arginine-glycine-aspartic acid (RGD) sequences could ...efficiently promote cell adhesion and proliferation. In this study, an electroactive and 3D bio-printable hydrogel was prepared through a two-step chemical cross-linking process. Specifically, residual free amino groups of methacrylated gelatin (GelMA) were cross-linked with the aldehyde groups of dibenzaldehyde-terminated telechelic polyethylene glycol (DF-PEG) via Schiff base bonds, forming a gel at 37 °C. During the subsequent 3D bio-printing process, GelMA underwent UV curing, forming a secondary cross-linked network to the mechanical strength and stability of the printed structure. The uniform dispersion of carbon nanotubes (CNTs) in the GelMA/DF-PEG composite hydrogel significantly increased its conductivity. The optimized GelMA/DF-PEG composite hydrogel, i.e., 30% GelMA and 25% DF-PEG (G30D25-CNTs), exhibited superior bio-printability. When the content of CNTs was above 4%, the conductivity of G30D25-CNTs hydrogel exceeded 10
S/m, which satisfied the needs of cells for micro-current stimulation. Furthermore, the pore microstructures, swelling behavior, degradation ability and cell toxicity of G30D25-CNTs electroactive hydrogels were thoroughly evaluated. Thus, the G30D25-CNTs hydrogel with 4% MWCNTs could be considered for further application in electrical stimulation of tissue regeneration such as muscle and cardiac nerve tissue repair.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Silicon oxynitride (SiN
O
) is a highly promising functional material for its luminescence performance and tunable refractive index, which has wide applications in optical devices, non-volatile ...memory, barrier layer, and scratch-resistant coatings. This review presents recent developments, and discusses the preparation methods, performance, and applications of SiN
O
film. In particular, the preparation of SiN
O
film by chemical vapor deposition, physical vapor deposition, and oxynitridation is elaborated in details.
The rational design of efficient Earth-abundant electrocatalysts for the ethanol oxidation reaction (EOR) is the key to developing direct ethanol fuel cells (DEFCs). Among these, the smart structure ...is highly demanded for highly efficient and stable non-precious electrocatalysts based on transition metals (such as Ni, Co, and Fe). In this work, high-performance NiCo-layered double hydroxide@carbon nanotube (NiCo-LDH@CNT) architectures with hollow nanocage structures as electrocatalysts for EOR were prepared via sacrificial ZIF-67 templates on CNTs. Comprehensive structural characterizations revealed that the as-synthesized NiCo-LDH@CNTs architecture displayed 3D hollow nanocages of NiCo-LDH and abundant interfacial structure between NiCo-LDH and CNTs, which could not only completely expose active sites by increasing the surface area but also facilitate the electron transfer during the electrocatalytic process, thus, improving EOR activity. Benefiting from the 3D hollow nanocages and interfacial structure fabricated by the sacrificial ZIF-67-templated method, the NiCo-LDH@CNTs-2.5% architecture exhibited enhanced electrocatalytic activity for ethanol oxidation compared to single-component NiCo-LDH, where the peak current density was 11.5 mA·cm
, and the j
/j
value representing the resistance to catalyst poisoning was 1.72 in an alkaline environment. These results provide a new perspective on the fabrication of non-precious metal electrocatalysts for EOR in DEFCs.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Implantable electrical devices offer a variety of potential diagnostic options and treatments in different medical fields. Especially in the absence of specific drugs, the implantable nerve ...electrodes (INEs) are one of the main treatments for neurological diseases such as epilepsy, Parkinson’s disease, Alzheimer’s disease, etc. INEs are helpful in studying and regulating nervous system via recording nerve electrical signals or stimulating nerve tissue, but the mechanical mismatch between rigid electrode and soft biological tissue is a critical challenge for long-term implantation. The advances in micromachining technologies and materials have greatly promoted the development of INEs, such as enhanced biocompatibility, reduced foreign body reactions, and structural innovation. In particular, the mechanical performances of flexible implantable electrode and soft biological tissue matched better with less tissue damage. In this review, the implantable flexible nerve electrodes (IFNEs) based on functionalized substrates, intelligent electrodes, and innovative structures are elaborated and discussed. We summarized their various applications in neural prosthesis and neural signal recording. We also discussed the questions and possible methods for developing future IFNEs in the perspective.
•The IFNEs based on functionalized materials and innovative structures are elaborated and discussed.•The various applications of IFNEs in neural prosthesis and neural signal recording are summarized in the manuscript.•The questions and possible methods for developing future IFNEs are discussed in the perspective.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Monolayer nanosheets have gained significant attention as functional materials and also in photo/electrocatalysis due to their unique physical/chemical properties, abundance of highly exposed ...coordination sites, edges, and corner sites, motivating the pursuit of highly active monolayer nanosheets. NiFe-based layered double hydroxide (NiFe-LDH) nanosheets have been regarded as the most efficient electrocatalysis for oxygen evolution. However, the limited catalytic active site and the stacking layer limited the performance. Therefore, by introducing highly electroactive Co ions into monolayer NiFe-LDH, the obtained ternary NiFeCo-LDH monolayer structure possessed an increased concentration of defect (oxygen and metal vacancies), providing enough unsaturated coordination sites, benefitting the electrocatalytic water oxidation, as also explained by the density functional theory (DFT). This work reported an efficient strategy for the synthesis of ternary monolayer LDH in the application of energy conversion and storage.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
In recent years, optoelectronics and related industries have developed rapidly. As typical optoelectronics devices, photodetectors (PDs) are widely applied in various fields. The functional materials ...in traditional PDs exhibit high hardness, and the performance of these rigid detectors is thus greatly reduced upon their stretching or bending. Therefore, the development of new flexible PDs with bendable and foldable functions is of great significance and has much interest in wearable, implantable optoelectronic devices. Graphene with excellent electrical and optical performance constructed on various flexible and rigid substrates has great potential in PDs. In this review, recent research progress on graphene-based flexible PDs is outlined. The research states of graphene conductive films are summarized, focusing on PDs based on single-component graphene and mixed-structure graphene, with a systematic analysis of their optical and mechanical performance, and the techniques for optimizing the PDs are also discussed. Finally, a summary of the current applications of graphene flexible PDs and perspectives is provided, and the remaining challenges are discussed.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Cyanobacterial blooms are one of the most serious water pollution problems for freshwater lakes. The treatment of blooms requires a lot of material and financial resources, so an early accurate ...prediction of cyanobacterial blooms is a very important way to deal with the outbreak of them. But it is challenging to predict the cyanobacterial blooms due to the uncertainty and complexity of their growth process. To deal with this problem, an improved attention-based bidirectional long short-term memory (LSTM) model is proposed in this paper, to make multistep predictions of chlorophyll-
a
concentration, which is a recognized characterization of algae activity. Firstly, the convolutional neural network (CNN) is used to extract data features and spatiotemporal correlation. Secondly, the bidirectional LSTM network (BiLSTM) is used to predict the concentration of chlorophyll-
a
based on the extracted features. Finally, the attention mechanism is used to calculate the weights for the characteristic factors that affect the chlorophyll-
a
concentration. At last, some experiments are carried out based on the real monitoring data of a platform in the Taihu Lake area. Compared with the prediction results of the other four state-of-the-art deep learning methods, the results show that the proposed method in this paper has the highest prediction accuracy.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
PDF
