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At present, the target tracking method based on the correlation operation mainly uses deep learning to extract spatial information from video frames and then performs correlations on this basis. However, it does not extract the motion features of tracking targets on the time axis, and thus tracked targets can be easily lost when occlusion occurs. To this end, a spatiotemporal motion target tracking model incorporating Kalman filtering is proposed with the aim of alleviating the problem of occlusion in the tracking process. In combination with the segmentation model, a suitable model is selected by scores to predict or detect the current state of the target. We use an elliptic fitting strategy to evaluate the bounding boxes online. Experiments demonstrate that our approach performs well and is stable in the face of multiple challenges (such as occlusion) on the VOT2016 and VOT2018 datasets with guaranteed real-time algorithm performance.

A series of cinnamic acid (CA)-esterified debranched starch (CDS) containing aromatic systems were prepared and successfully fabricated as nanoparticles to encapsulate curcumin by taking advantage of the additional π-π interactions provided from CA. The CDS nanoparticles (CDS NPs) have good dispersion (polydispersity index of 0.124-0.314) and sizes range of 130-330 nm. The excellent biosafety of CDS NPs was demonstrated by hemolysis, cytotoxicity and mutagenicity assays. Efficient encapsulation (LC = 26.86 %) and sustained release of curcumin were achieved, and the curcumin-encapsulated CDS NPs (CDS-Cur NPs) increased 266-fold water solubility and 2.3-6.5-fold photothermal stability for curcumin, compared to free curcumin. Functional studies showed that CDS-Cur NPs exhibited superior biofilm scavenging ability, with a 2-4.3-fold improvement compared to free curcumin. In addition, CDS-Cur NPs also exhibited far superior antibacterial effects than free curcumin in a bacteriostatic food model of chicken breast. This study not only provides a new scheme for the efficient loading of curcumin, but also provides new ideas for the usage of starch-based materials in antibacterial applications.

A new oligothiophene derivative (3TY) was synthesized, and used as a highly selective hydrazine (N2H4) chemosensor in ∼100% aqueous solution with “naked-eye” colorimetric and “turn-on” fluorimetric response. This chemosensor 3TY enabled ultrafast and ultrasensitive detection of hydrazine with ultralow detection limit of 1.45 nM (0.04 ppb) in a wide sensing pH range from 6 to 10. The sensing mechanism of 3TY toward hydrazine was strongly and fully confirmed. More importantly, colorimetric paper test strip and solid support silica are easily prepared by 3TY for on-site and real-time detection of hydrazine. Furthermore, 3TY displays many potential applications for detecting N2H4 in environmental water and human urine along with bio-imaging in living HeLa cells.

Using Hg

A new simple carbazole Schiff base (CBS) with typical aggregation-induced emission enhancement (AIEE) property was designed and synthesized based on carbaldehyde and 2-hydroxybenzohydrazide units, which was successfully utilized as a new dual-responsive colorimetric/fluorimetric chemosensor for highly selective and sensitive “turn-off” fluorescence detection of Hg2+ and “turn-on” fluorescence sensing Al3+ in near-perfect aqueous media based on metal chelation mechanism. The low detection limits of CBS for Hg2+ and Al3+ were respectively determined to be 14.7 nM and 47.2 nM, far lower than the WHO guidelines for drinking water, which permitted its nano-level determination in real samples. The CBS for Hg2+/Al3+ sensing displayed outstanding advantages of pH stability, excellent reversibility, ultra-fast response, stronger anti-interference capability and lower cytotoxicity compared with other related chemosensors. The binding mode of CBS with Hg2+/Al3+ was determined to be a 1:1 complexation stoichiometry using Job’s plot analysis and fluorescent titration curve, which further confirmed by FTIR and 1H NMR analysis. Due to its good colorimetric/fluorimetric properties, a simple cost-effective portable on-site test strip was developed that allows for visual, fast, reliable and convenient detecting Hg2+/Al3+ in environmental analysis. Moreover, chemosensor CBS has successful application in building molecular logic gates. Furthermore, the CBS was successfully applied in soil, environmental water, and food samples analysis and live-cell imaging, demonstrated its great potentials in environmental and biological applications.

A new bithiophene-based biocompatible fluorescent and colorimetric sensor 2TD capable of detecting hypochlorite (ClO−) in enviro/biosystem was successfully synthesized. This sensor 2TD underwent a highly specific and sensitive oxidation reaction with ClO− and produced a bithiophene aldehyde (2T-CHO) emitting strong blue fluorescence, which was strongly confirmed by 1H NMR, HRMS, FTIR and DFT calculation. The 2TD for detecting ClO− displays an ultra-fast response (25 s), great water-solubility (~100% aqueous solution), wide pH working range (7–11), excellent anti-interference capability, and ultra-sensitivity with low detection limit of 8.3 nM. Colorimetric test strips demonstrate that 2TD can be utilized as a cost-effective and efficient solid-state sensor for rapidly and conveniently sensing ClO− with great sensitivity in practical applications. With the robust applicability, the 2TD was successfully utilized to determine/image ClO− in environmental water and live-cells. More interestingly, this developed sensor 2TD could be used as an efficient test tool for ClO− sensing.

In this work, a novel carbazole-indandione based red-emitting fluorescent sensor CBI was developed, which exhibited typical and interesting aggregation-induced emission (AIE) characteristics with a large Stokes shift in mixed aqueous media. CBI as a colorimetric and fluorimetric sensor for sensing hydrazine in ~100% aqueous media shows ultrarapid response, excellent selectivity, and great sensitivity with a low detection limit of 1.18 ppb. The mechanism of CBI for highly sensing hydrazine was proved by fluorescence, FTIR, 1H NMR and HRMS spectra. Interestingly, the CBI was not only applied to sensitively detect aqueous N2H4 in water, human urine and live cells, but also was conveniently utilized to visualize gaseous N2H4 with sensitive naked-eye color diversification. Additionally, owing to its intense fluorescence irradiated by UV light, the CBI was significantly used as a new fluorescent ink for writing and drawing as well as a writable fluorescent display material.

A dual-function bithiophene-Meldrum's acid based chemosensor 2TM was developed, which displayed ultrafast, colorimetric and fluorescence turn-on responses for CN− and ClO− with specific selectivity and high sensitivity. The sensor 2TM for CN− detection in DMSO/H2O (1/3, V/V) solution was based on the nucleophilic addition of CN− to sensor, which resulted in remarkable spectral and discernible color changes. Meanwhile, 2TM showed specific selectivity for ClO− in 100% aqueous solution based on the sensing mechanism of oxidative cleavage of C C bond. The detection limits were obtained to be 0.96 μM for CN− and 48 nM for ClO−. The sensing mechanism of 2TM toward CN− and ClO− was investigated by job'plot, FTIR, 1H NMR, HRMS and optical spectra. The sensor 2TM loaded colorimetric test strips/supported silica measurements demonstrated to be a portable, eco-friendly and ultrafast device for real-time and on-site visual detection of CN− and ClO− in water by the naked eye. More importantly, sensor 2TM with excellent photophysical properties and low biotoxicity was successfully applied to detect CN− and ClO− in live cells and environmental water samples, as well as capable of monitoring CN− in the natural food samples, illustrating its practical utility in biological and environmental systems.

A novel highly sensitive and selective phenothiazine-based sensor PN has been successfully synthesized. The sensor PN showed specific recognition towards Cu2+ through dual “naked-eye” colorimetric and “turn-off” fluorescence responses in DMSO/H2O (1:3, V/V) solution with ultrafast response and good reversibility. The detection limit was determined to be as low as 0.179 µM, which was much lower than drinking water permission concentration by the United States Environmental Protection Agency (～20 µM) and the World Health Organization (～30 µM). The 1:1 binding mechanism of PN with Cu2+ was proposed and well confirmed by fluorescence titration, Job’s plot, 1H NMR, HRMS, FTIR analysis and DFT studies. Moreover, the sensor PN was successfully applied to sensitively detect the Cu2+ ions in real water samples with good accuracy and high precision. Furthermore, sensor PN could serve as a cost-effective solid-state sensor for immediate, convenient and “naked-eye” colorimetric detection of Cu2+ in environmental samples.

Using Hg2+-promoted deprotection reaction, we have developed a new fluorescent turn-on sensor 2TS based on bithiophene fluorophore for Hg2+ detection. The sensing mechanism of 2TS towards Hg2+ was strongly proved by 1H NMR, FTIR, HRMS, UV–vis and fluorescence spectra. Remarkly, 2TS towards Hg2+ in 100% aqueous solution shows high sensitivity with a low detection limit of 19 nM, superior selectivity and ultra-rapid response of 20 s during a wide sensing pH range from 4 to 10. Taking advantage of the excellent properties, the low-cost sensor 2TS-based filter paper/TLC test strips were fabricated for visual, immediate and quantitative detection of Hg2+ in water, proving its applicability towards sensitive in-situ and on-site detection. Meanwhile, 2TS showed high analytical performance for Hg2+ detection in water, seafood as well as human urine samples. Moreover, thanks to the good water solubility, negligible cytotoxicity, good biocompatibility and cell-membrane permeability, 2TS was further applied to effectively image Hg2+ in live cells. Furthermore, the developed sensor 2TS acted as good fluorescent display material for Hg2+ with obvious color change.

Titanium dioxide (TiO 2 ) nanocrystals with specific exposed crystal facet have attracted considerable interest due to their promising applications in the fields of energy and environment. In this paper, we report on a simple solvothermal approach for the synthesis of anatase TiO 2 octahedra with high yield, using titanium(IV) sulfate and hydrazine hydrate as the starting materials. The formation mechanism of anatase TiO 2 octahedra is suggested. The samples were characterized with XRD, Raman, SEM, TEM, FTIR, XPS, and UV/vis techniques, and further tested as a candidate in photocatalysis to decompose methyl orange in aqueous solution at room temperature. The results show that SO 4 2− ions not only benefit the formation of octahedral nanocrystals, but also inhibit nitrogen doping into TiO 2 matrix. More importantly, it is found that the octahedral TiO 2 nanocrystals show enhanced photocatalytic activity compared to TiO 2 P25 and anatase TiO 2 counterparts.

Spinel LiMn 2 O 4 was synthesized by solid state reaction. 5.0 wt.% of La 2 O 3 was coated on the surface of LiMn 2 O 4 via ball-milling method, followed by calcination at 650 °C for 5 h in the air. The uncoated and La 2 O 3 -coated LiMn 2 O 4 materials were physically characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller surface area measurements. It was observed that Li/LiMn 2 O 4 electrode obtained the capacity retention of 76.7% after 205 cycles at 1 C rate at 25 °C while that of the coated sample was 90.1%. At 55 °C, the bare and coated LiMn 2 O 4 showed a capacity retention of 69.4% and 82.6% after 95 cycles, respectively. Rate capability was also improved. The capacity retention of uncoated and La 2 O 3 -coated materials reduced to 46.9% and 80.3% at 10 C-rate, respectively.