9 research outputs found
Bidirectional Graph Reasoning Network for Panoptic Segmentation
Recent researches on panoptic segmentation resort to a single end-to-end
network to combine the tasks of instance segmentation and semantic
segmentation. However, prior models only unified the two related tasks at the
architectural level via a multi-branch scheme or revealed the underlying
correlation between them by unidirectional feature fusion, which disregards the
explicit semantic and co-occurrence relations among objects and background.
Inspired by the fact that context information is critical to recognize and
localize the objects, and inclusive object details are significant to parse the
background scene, we thus investigate on explicitly modeling the correlations
between object and background to achieve a holistic understanding of an image
in the panoptic segmentation task. We introduce a Bidirectional Graph Reasoning
Network (BGRNet), which incorporates graph structure into the conventional
panoptic segmentation network to mine the intra-modular and intermodular
relations within and between foreground things and background stuff classes. In
particular, BGRNet first constructs image-specific graphs in both instance and
semantic segmentation branches that enable flexible reasoning at the proposal
level and class level, respectively. To establish the correlations between
separate branches and fully leverage the complementary relations between things
and stuff, we propose a Bidirectional Graph Connection Module to diffuse
information across branches in a learnable fashion. Experimental results
demonstrate the superiority of our BGRNet that achieves the new
state-of-the-art performance on challenging COCO and ADE20K panoptic
segmentation benchmarks.Comment: CVPR202
The synthesis of novel AIE emitters with the triphenylethene-carbazole skeleton and para-/meta-substituted arylboron groups and their application in efficient non-doped OLEDs
Four novel aggregation-induced emission (AIE)-active luminogens (p-DPDECZ, p-DBPDECZ, m-DPDECZ and m-DBPDECZ) with triphenylethene-carbazole skeleton and para-/meta-substituted arylboron groups have been synthesized. Their structures are fully characterized using elemental analysis, mass spectrometry and proton nuclear magnetic resonance spectroscopy. The thermal stabilities, photophysical properties, electronic structures, and electrochemical properties of these molecules are investigated systematically using thermal analysis, UV-vis absorption spectroscopy, fluorescence spectroscopy, theoretical calculation and electrochemical methods. The effects of donor–acceptor interaction and conjugation degree on the photoluminescent and electroluminescent properties of these compounds are investigated. The results show that these donor–AIE–acceptor type compounds exhibit good thermal stability and electrochemical stability as well as AIE properties. Non-doped fluorescent OLEDs fabricated by using para-linked p-DPDECZ as an emitting layer emits a green light with a turn-on voltage of 4.8 V, a maximum brightness of 30210 cd m-2 and a maximum current efficiency of 9.96 cd A-1. While the OLED prepared with meta-linked m-DBPDECZ exhibits efficient blue light emission with a maximum current efficiency of 4.49 cd A-1 and a maximum luminance of 16410 cd m-2. The electroluminescence properties of these compounds demonstrate their potential application in OLEDs
Robust Red Organic Nanoparticles for In Vivo Fluorescence Imaging of Cancer Cell Progression in Xenografted Zebrafish
10.1002/adfm.201701418ADVANCED FUNCTIONAL MATERIALS273
Continual Object Detection via Prototypical Task Correlation Guided Gating Mechanism
Continual learning is a challenging real-world problem for constructing a
mature AI system when data are provided in a streaming fashion. Despite recent
progress in continual classification, the researches of continual object
detection are impeded by the diverse sizes and numbers of objects in each
image. Different from previous works that tune the whole network for all tasks,
in this work, we present a simple and flexible framework for continual object
detection via pRotOtypical taSk corrElaTion guided gaTing mechAnism (ROSETTA).
Concretely, a unified framework is shared by all tasks while task-aware gates
are introduced to automatically select sub-models for specific tasks. In this
way, various knowledge can be successively memorized by storing their
corresponding sub-model weights in this system. To make ROSETTA automatically
determine which experience is available and useful, a prototypical task
correlation guided Gating Diversity Controller(GDC) is introduced to adaptively
adjust the diversity of gates for the new task based on class-specific
prototypes. GDC module computes class-to-class correlation matrix to depict the
cross-task correlation, and hereby activates more exclusive gates for the new
task if a significant domain gap is observed. Comprehensive experiments on
COCO-VOC, KITTI-Kitchen, class-incremental detection on VOC and sequential
learning of four tasks show that ROSETTA yields state-of-the-art performance on
both task-based and class-based continual object detection
Solution-processable, star-shaped bipolar tetraphenylethene derivatives for the fabrication of efficient nondoped OLEDs
Organic light-emitting diodes (OLEDs) based on solution-processable small molecules are attracting intense attention, as such technology combines the merits of low-cost solution processability of polymers and finely defined structural uniformity of small molecules. Small-molecule tetraphenylethene (TPE) derivatives are excellent solid-state light emitters featuring aggregation-induced emission (AIE) characteristics, however those that can be used in solution-processable devices are very rare. To address this issue, herein, a series of novel star-shaped bipolar TPE derivatives are synthesized and characterized. Their thermal stabilities, photophysical properties, electronic structures, electrochemical behaviors, and application in solution-processed OLEDs are investigated systematically. These luminogens exhibit AIE characteristics and excellent fluorescence quantum yields up to 95% in the solid state. Nondoped OLEDs are successfully fabricated through a spin-coating method. The solution-processed OLEDs [ITO (130 nm)/PEDOT:PSS (40 nm)/emitter (70 nm)/TPBi (30 nm)/Ba (4 nm)/Al (120 nm)] adopting star- shaped TPE derivatives as light-emitting layers show peak luminance of 11665 cd m-2 and high electroluminescence (EL) efficiencies up to 8.3 cd A-1, 2.6 % and 7.5 lm W-1. These results demonstrate a promising avenue towards efficient nondoped OLEDs based on solution-processable AIE-active small molecules
Long-Term Tracking of the Osteogenic Differentiation of Mouse BMSCs by Aggregation-Induced Emission Nanoparticles
Bone marrow-derived mesenchymal stem
cells (BMSCs) have shown great
potential for bone repair due to their strong proliferation ability
and osteogenic capacity. To evaluate and improve the stem cell-based
therapy, long-term tracking of stem cell differentiation into bone-forming
osteoblasts is required. However, conventional fluorescent trackers
such as fluorescent proteins, quantum dots, and fluorophores with
aggregation-caused quenching (ACQ) characteristics have intrinsic
limitations of possible interference with stem cell differentiation,
heavy metal cytotoxicity, and self-quenching at a high labeling intensity.
Herein, we developed aggregation-induced emission nanoparticles decorated
with the Tat peptide (AIE-Tat NPs) for long-term tracking of the osteogenic
differentiation of mouse BMSCs without interference of cell viability
and differentiation ability. Compared with the ability of the commercial
Qtracker 655 for tracking of only 6 passages of mouse BMSCs, AIE-Tat
NPs have shown a much superior performance in long-term tracking for
over 12 passages. Moreover, long-term tracking of the osteogenic differentiation
process of mouse BMSCs was successfully conducted on the biocompatible
hydroxyapatite scaffold, which is widely used in bone tissue engineering.
Thus, AIE-Tat NPs have promising applications in tracking stem cell
fate for bone repair
Improving Electron Mobility of Tetraphenylethene-Based AIEgens to Fabricate Nondoped Organic Light-Emitting Diodes with Remarkably High Luminance and Efficiency
Robust
light-emitting materials with strong solid-state fluorescence
as well as fast and balanced carrier transporting ability are crucial
to achieve high-performance organic light-emitting diodes (OLEDs).
In this contribution, two linear tetraphenylethene (TPE) derivatives
(TPE-TPAPBI and TPE-DPBI) that are functionalized with hole-transporting
triphenylamine and/or electron-transporting 1,2-diphenyl-1<i>H</i>-benzimidazole groups are synthesized and fully characterized.
Both TPE-TPAPBI and TPE-DPBI have aggregation-induced emission attributes
and excellent photoluminescence quantum yields approaching 100% in
vacuum deposited films. They also possess good thermal property, giving
high decomposition temperatures (480 and 483 °C) and glass-transition
temperatures (141 and 157 °C). TPE-TPAPBI and TPE-DPBI present
high electron mobilities of 1.80 × 10<sup>–5</sup> and
1.30 × 10<sup>–4</sup> cm<sup>2</sup> V <sup>–1</sup> s<sup>–1</sup>, respectively, at an electric field of 3.6
× 10<sup>5</sup> V cm<sup>–1</sup>, which are comparable
or even superior to that of 1,3,5-tri(1-phenylbenzimidazol-2-yl)benzene.
The nondoped OLED device employing TPE-TPAPBI as active layer performs
outstandingly, affording ultrahigh luminance of 125 300 cd
m<sup>–2</sup>, and excellent maximum external quantum, power
and current efficiencies of 5.8%, 14.6 lm W<sup>–1</sup>, and
16.8 cd A<sup>–1</sup>, respectively, with very small roll-offs,
demonstrating that TPE-TPAPBI is a highly promising luminescent material
for nondoped OLEDs
High-Performance Doping-Free Hybrid White OLEDs Based on Blue Aggregation-Induced Emission Luminogens
Doping-free
white organic light-emitting diodes (DF-WOLEDs) have
aroused research interest because of their simple properties. However,
to achieve doping-free hybrid WOLEDs (DFH-WOLEDs), avoiding aggregation-caused
quenching is challenging. Herein, blue luminogens with aggregation-induced
emission (AIE) characteristics, for the first time, have been demonstrated
to develop DFH-WOLEDs. Unlike previous DFH-WOLEDs, both thin (<1
nm) and thick (>10 nm) AIE luminogen (AIEgen) can be used for devices,
enhancing the flexibility. Two-color devices show (i) pure-white emission,
(ii) high CRI (85), and (iii) high efficiency. Particularly, 19.0
lm W<sup>1–</sup> is the highest for pure-white DF-WOLEDs,
while 35.0 lm W<sup>1–</sup> is the best for two-color hybrid
WOLEDs with CRI ≥ 80. A three-color DFH-WOLED shows broad color-correlated
temperature span (2301–11628 K), (i) the first sunlight-like
OLED (2500–8000 K) operating at low voltages, (ii) the broadest
span among sunlight-like OLED, and (iii) possesses comparable efficiency
with the best doping counterpart. Another three-color DFH-WOLED exhibits
CRI > 90 at ≥3000 cd m<sup>–2</sup>, (i) the first
DF-WOLED
with CRI ≥ 90 at high luminances, and (ii) the CRI (92.8) is
not only the highest among AIE-based WOLEDs but also the highest among
DF-WOLEDs. Such findings may unlock an alternative concept to develop
DFH-WOLEDs