A strategy of adopting Ga2O3 alloyed
with
Al element to reduce the oxygen vacancy defect density and enhance
the interface barrier height of Ga2O3 heterojunction
is proposed to fabricate deep-UV photovoltaic detectors with high
thermal stability, high photoresponsivity, and fast response speed.
Here, a graphene/(AlGa)2O3/GaN device with a
photoresponsivity of ∼20 mA/W, a rise time of ∼2 μs,
and a decay time of ∼10 ms is presented at 0 V bias. At the
working temperature of 453 K, the device still exhibits a photo-to-dark
current ratio (PDCR) of ∼1.8 × 103, which is
1–2 orders of magnitude higher than that of the reported high-temperature
deep-UV film detectors. By comparing the formation energy of oxygen
vacancy defects and the interface barrier height of the heterojunction
at different temperatures in graphene/Ga2O3/GaN
and graphene/(AlGa)2O3/GaN systems, the strategy
of synthesizing (AlGa)2O3 ternary composite
alloy is proved to be reliable for fabricating high-performance deep-UV
photovoltaic detectors. The method proposed in this paper can provide
reference for the preparation of deep-UV photovoltaic detectors with
high photoresponsivity and thermal stability in the future.
Self-healing performance plays an important role in the in situ microinvasive injection of hydrogels, which can reduce sudden drug release and prolong the service life of hydrogels. In this paper, a multifunctional injectable and self-healing hydrogel for wound healing was developed. Chitosan (CS) was modified with TA to achieve potential adhesion, anti-inflammatory properties, and slower degradation rate. The hydrogel was formed by Schiff base reaction based on amino groups in CS and aldehyde groups in oxidized hyaluronic acid (OHA). The gel formation process was quick and convenient in mild conditions without extra initiators. Due to the dynamically reversible covalent bonds, the hydrogel could self-heal within 2 min after injection. It also had good biocompatibility and hemostatic performance. With the addition of TA, the hydrogel acquired antiinflammatory properties and promoted cell growth, effectively accelerating the wound-healing process in vivo. The CS−TA/ OHA hydrogel is expected to be used for skin repair.
Exploring new materials and structures to construct synaptic devices represents a promising route to fundamentally approach novel forms of computing. Nanocrystals (NCs) of halide perovskites possess unique charge transport characteristics, i.e., ionic−electronic coupling, holding considerable promise for energy-efficient and reconfigurable artificial synapses. Herein, we report solution-processed thin-film memristors from all-inorganic CsPbBr 3 perovskite NCs, functioning as an electrically programmable analog memory with good stability. The devices are demonstrated to successfully emulate a number of essential synaptic functions with low power consumption, including reversible potentiation and depression, short-term plasticity (STP), paired-pulse facilitation (PPF), and long-term plasticity (LTP), such as spike-number-dependent plasticity (SNDP), spike-rate-dependent plasticity (SRDP), spike-timing-dependent plasticity (STDP), and spike-voltage-dependent plasticity (SVDP). It is proposed that a coupled capacitive and inductive phenomenon originating from charge trapping and ion migration in CsPbBr 3 NC films, controlled by the amplitude and timing of the programming pulses, defines the degree of synaptic plasticity. A transition emerges from the fast traprelated capacitive regime to a slow ionic inductive regime, which enables continuous change of the film resistance and the magnitude of the electronic current, analogous to the synaptic weight modulation in biological synapses.
Nowadays phone distraction has started to become an increasingly recognized phenomenon. This article aims to examine the influences of phone use on pedestrian crossing behavior at signalized intersections in China. Using video recording and manual counting, pedestrian crossing behavior, age, gender, phone use, and waiting time are obtained at four signalized intersections. Totally, 4196 pedestrians are observed in four peak hours. Among them, 328 pedestrians (7.82%) are using their mobile phones, including 162 male pedestrians and 166 female pedestrians. The average phone use rate in different age groups are presented as follows: children (4.49%), youth (10.69%), middle-aged (6.87%), and elderly (1.15%). In terms of the phone using behavior on the crosswalk, age is a significant factor, while gender is not. For the type of violation behavior, the results show that pedestrians who use mobile phones are most likely to be late starters. In addition, some other important results are found: mobile phone use can raise the violation of pedestrian crossing behavior; pedestrians using their phones are more likely to cross on red; and pedestrians using their phones while crossing walk more slowly. Finally, the application significance of this study and some recommendations are provided to improve pedestrian safety.
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