分类: 光学 >> 量子光学 提交时间: 2023-02-19
摘要: This paper constructs the mapping relation from density of states (DOS) to UV-vis spectra by using an ab initio perspective. Taking BiOIO3 semiconductor photocatalyst as an example, the experimental verification was also carried out. The optical response of the material considers the superposition benefits of all possible transitions. Directly using the difference between valence band maximum (VBM) and conduction band minimum (CBM) will lead to an underestimate of the energy band gap. This paper provides a new idea of linking the density functional theory (DFT) data with experiment phenomenon.
分类: 材料科学 >> 电子、光学、磁材料 提交时间: 2023-10-26
摘要: Triboelectric nanogenerators (TENGs) are promising self-powering suppliesfor a diverse range of intelligent sensing and monitoring devices, especially due to their capability of harvesting electric energy from low frequency and small-scale mechanical motions. Inspired by the fact that contact-separation mode TENGs with small contact areas harvest high electrical outputs due to fringing effect, this study employed discontinuity on the dielectric side of contact-separation mode TENGs to promote fringing electric fields for the enhancement of electrical outputs. The results reveal that the TENGs with more discontinuities show higher overall electric performance. Compared to pristine TENGs, the TENGs with cross discontinuities increased the surface charge by 50% and the power density by 114%. However, one should avoid generating discontinuities on tribonegative side of TENGs using metal blade within a positive-ion atmosphere due to the neutralization through electrically conductive metal blade. The computational simulation validated that the TENGs with discontinuities obtained higher electrical outputs, and further investigated the effect of discontinuity gap size and array distance on TENGs performance. This study has provided a promising method for the future design of TENGs using discontinuous structures.
分类: 天文学 >> 天文学 提交时间: 2024-03-29 合作期刊: 《Research in Astronomy and Astrophysics》
摘要: A time-synchronization strategy for packetized transmission of target position about a large-aperture telescope observation control system has been proposed in this study. Compared with the existing telescope tracking strategy, the target position packing and sending strategy based on the time synchronization method proposed in this paper has the advantages of high stability and reliability. First, the telescope tracking observation control method was elaborated in this paper, including the motion pattern during telescope tracking. Then, the strategy for packetizes transmission of target positions based on time-synchronization is established and lists the detailed steps. Finally, the performance of the tracking strategy is verified using the 2.5 m telescope for the simulated uniform speed star and the blind-tracking fixed star HIP 31216, respectively. The test results show that the accuracy root mean square of the tracking strategy proposed in this paper is less than 002 at 30 minutes, and the performance is much better than the design requirement of 03. The most important advantage of this tracking strategy is that the telescope can guarantee normal tracking for a certain period of time even if the hardware or software of the host computer is abnormal.
分类: 天文学 >> 天文学 提交时间: 2024-05-24 合作期刊: 《Research in Astronomy and Astrophysics》
摘要: Owing to the broad energy coverage of Insight-HXMT in the hard X-ray band, we detected the highest energy of pulsation exceeding 200 keV around the 2017–2018 outburst peak of the first Galactic pulsating ultraluminous X-ray source (PULX) Swift J0243.6+6124, which is the highest energy detected from PULXs to date. We also obtained the highest energy of pulsation of every exposure during the outburst in 2017–2018, and found the highest energy is roughly positively correlated with luminosity. Using our newly developed method, we identified the critical luminosity being 4 × 1038 erg s−1 when the main peaks of the low and high energy pulse profiles became aligned, which separates the fan-beam dominated and pencil-beam dominated accretion regimes. Above the critical luminosity, the phase of the main peak shifted gradually from 0.5 to 0.8 until the outburst peak in all energy bands is reached, which is in agreement with the phase shift found previously at low energies. Our result is consistent with what is derived from spectral analysis.
分类: 生物学 >> 生态学 提交时间: 2017-11-17
摘要: A novel dipeptidyl peptidase IV inhibitor hit (5, IC50 = 0.86 mu M) was structurally derived from our recently disclosed preclinical candidate 4 by replacing the cyanobenzyl with a butynyl based on pharmacophore hybridization. A hit-to-lead optimization effort was then initiated to improve its potency. Most N-substituted analogs exhibited good in vitro activity, and compound 180 (IC50 = 1.55 nM) was identified to be a potent dipeptidyl peptidase IV inhibitor with a significantly improved pharmacokinetic properties (bioavailablity: 41% vs 82.9%; T-1/2: 2 h vs 4.9 h). (C) 2013 Elsevier Ltd. All rights reserved.
分类: 生物学 >> 生态学 提交时间: 2017-11-17
摘要: We previously reported a highly potent DPP-IV inhibitor 6 with low in vivo efficacy. While trying to maintain consistent in vitro and in vivo biological activity, we initiated a pharmacokinetic property-driven optimization to improve the metabolic stability and permeability of inhibitor 6. A simple scaffold replacement of thienopyrimidine with pyrrolopyrimidine (21a) led to significantly improved metabolic stability (4% vs. 65% remaining). Further modification of the pyrrolopyrimidine scaffold to produce compound 21j resulted in much better oral bioavailability than 6. Importantly, compound 21j exhibits greater in vivo efficacy than does 6 and Alogliptin and is worthy of further development. (C) 2012 Elsevier Masson SAS. All rights reserved.