No abstract

In this paper, we present a new on-device automatic speech recognition (ASR) system based on monotonic chunk-wise attention (MoChA) models trained with large (> 10K hours) corpus. We attained around 90% of a word recognition rate for general domain mainly by using joint training of connectionist temporal classifier (CTC) and cross entropy (CE) losses, minimum word error rate (MWER) training, layer-wise pretraining and data augmentation methods. In addition, we compressed our models by more than 3.4 times smaller using an iterative hyper low-rank approximation (LRA) method while minimizing the degradation in recognition accuracy. The memory footprint was further reduced with 8-bit quantization to bring down the final model size to lower than 39 MB. For on-demand adaptation, we fused the MoChA models with statistical n-gram models, and we could achieve a relatively 36% improvement on average in word error rate (WER) for target domains including the general domain.

A novel electron-accepting bis-lactam building block, 3,7-dithiophen-2-yl-1,5-dialkyl-1,5-naphthyridine-2,6-dione (NTDT), and a conjugated polymer P­(NTDT-BDT) comprising NTDT as an electron acceptor and benzo­[1,2-b:4,5-b′]­dithiophene (BDT) as an electron donor are designed and synthesized for producing efficient organic solar cells. The thermal, electronic, photophysical, electrochemical, and structural characteristics of NTDT and P­(NTDT-BDT) are studied in detail and compared with those of the widely used bis-lactam acceptor 3,6-dithiophen-2-yl-2,5-dialkylpyrrolo­[3,4-c]­pyrrole-1,4-dione (DPPT) and its polymer P­(DPPT-BDT). Compared to DPPT derivatives, NTDT and P­(NTDT-BDT) exhibit remarkably higher absorption coefficients, deeper highest occupied molecular orbital energy levels, and more planar conformations. A bulk heterojunction solar cells based on P­(NTDT-BDT) exhibit power conversion efficiency of up to 8.16% with high short circuit current (J sc) of 18.51 mA cm–2, one of the highest J sc values yet obtained for BDT-based polymer. Thus, it is successfully demonstrated that the novel bis-lactam unit NTDT is a promising building block for use in organic photovoltaic devices.

Superoxide, NO, and peroxynitrite are involved in renal I/R injury. The reduction of peroxynitrite formation, via inhibition of superoxide or NO, or the induction of peroxynitrite decomposition may be beneficial in renal I/R injury.

We report a new β-dicyanodistyrylbenzene (β-DCS)-based polymer (PBDCS), which enables efficient fullerene and non-fullerene organic solar cells with low Eloss and high EQE.

We present a developed highly balanced and thermally stable ambipolar semiconducting polymer PBCDC consisting of diketo­pyrrolo­[3,4-c]­pyrrole and benzo­[1,2-b:4,5-b′]­dithiophene building blocks connected by a cyanovinylene linker unit. Stabilization of the frontier molecular orbitals and delocalization of the LUMO on the whole structural unit were realized by introducing the strong electron-withdrawing cyanovinylene linker. In addition to such electronic effects, the molecular stacking and crystallinity of the polymer film were significantly controlled by the presence of the cyanovinylene linker, which was preserved with no variation at different annealing temperatures. As a result of these electronic and structural effects of cyanovinylene, organic field-effect transistors based on the PBCDC exhibit highly balanced hole and electron mobilities of μh,max ∼ 0.2 cm2 V–1 s–1 and μe,max ∼ 0.2 cm2 V–1 s–1, respectively, which are virtually independent of the annealing temperature over the range of 80–250 °C.

A series of amorphous polymers of poly(arylenevinylene) copolymers, in which heterocycles (furan, thiophene, selenophene) and dialkoxy phenylenes were alternatingly linked by vinylene unit, was prepared by the Horner-Emmons reaction. Because of high regularity of the polymer microstructure by selective formation of E olefin, the resulting polymers showed good interchain π-π stacking in thin film state despite being amorphous polymers. When the A,B-alternating poly(phenylene thiophene vinylene), in particular with the bis(heptoxy) group, was used as a semiconductor material in an organic thin-film transistor, the best hole mobility up to 0.03 cm 2 /(V s) was observed, which is one of the highest values recorded from amorphous polymer film. The mobility was even improved to 0.06 cm 2 /(V s) when the polymer was blended with well-dispersed single-wall carbon nanotubes (SWCNT). Although this mobility is lower than that from the best crystalline polymers, these amorphous polymers showed advantages such as the device performances being less sensitive to both their molecular weights and the choice of gate insulators than the typical crystalline polymers.

No abstract