Controlling the nonradiative deactivation of triplet states and tuning the singlet-triplet energy gap are the major challenges to develop materials exhibiting thermally activated delayed fluorescence (TADF) and room temperature phosphorescence...

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In this report, we propose a scheme to provide online tweet recommendation for the movies. The method is based on user behavior patterns and interactions (based on retweets and favorites) performed on the tweets expressing the users' ratings. Traditional recommendation algorithms develop a model offline using training data and this model is then used to generate online recommendations. Training in traditional recommender systems is a very time consuming and hence cannot be used in domains which generate data very fast. To address this problem, we propose a novel recommendation algorithm, based on Extreme Learning Machine (ELM). We call our approach Extreme Learning Machine based Recommendation technique (ELMR). ELM is a learning system like single layer feed-forward neural network (SLFNN) which significantly reduces the amount of time needed for training of the system. It has been widely used for many applications requiring generalization, classification and prediction. The proposed ELMR method performs parameter learning with an intention to optimize recommendations on user engagement with an item (in this case tweet). The initial training and updating of ELMR are very fast and can be finished in real time. The experimental results show that the mean recommendation time of ELMR is shorter than MLP/ANN and naïve based classification algorithms reported in other reports with better accuracy.

<p></p><p>Control of nonradiative deactivation of triplet states and tuning the singlet-triplet energy gap (ΔE_ST) are the major challenges to develop materials exhibiting thermally activated delayed fluorescence (TADF) and room temperature phosphorescence (RTP). Herein, we propose a new class of multichromophoric tridonor-acceptor (D₃-A) compounds with rigid and flexible π-spacer having N-rich pyridoquinoxaline (PQ) and pyridopyrazine (PZ) acceptor core, respectively. The molecule with carbazole (Cz) donors at <i>meta</i> to quinoxaline (QX) nitrogen of rigid PQ core exhibits TADF. Whereas, the variation of the linkage position of Cz to PQ as well as twisted and flexible PZ core show predominantly RTP due to relatively higher singlet-triplet energy gap (ΔE_ST). Increasing the donor strength with phenoxazine (PO) in PZ system leads to simultaneous TADF and RTP. Further, we demonstrate the promising scope of all-organic triplet harvesting materials in solid-state security encryption.</p><br><p></p>