A Novel Approach to All-Optical Generation of Ultra-Wideband Signals

Abstract

The generation of ultra-wideband signals in the optical domain is highly desirable for ultra-wideband-over-fiber systems, which has recently become a topic of interest. In this article, a novel and simple approach to achieve all-optical generation of ultra-wideband signals is proposed, which is based on delaying and superimposing optical Gaussian pulses with opposite polarities. The proposed system is capable of generating both ultra-wideband monocycle and doublet pulses, and the polarity of the generated ultra-wideband monocycle pulses can be fast-switched to implement pulse polarity modulation with the required bit pattern. A model to describe the proposed system is developed, and the generation of ultra-wideband signals is demonstrated with simulations and a proof-of-concept experiment.     

Hydrogen Spillover Enhanced Hydroxyl Formation and Catalytic Activity Toward CO Oxidation at the Metal/Oxide Interface

H₂‐promoted catalytic activity of oxide‐supported metal catalysts in low‐temperature CO oxidation is of great interest but its origin remains unknown. Employing an FeO(111)/Pt(111) inverse model catalyst, we herewith report direct experimental evidence for the spillover of H(a) adatoms on the Pt surface formed by H₂ dissociation to the Pt?FeO interface to form hydroxyl groups that facilely oxidize CO(a) on the neighboring Pt surface to produce CO₂. Hydroxyl groups and coadsorbed water play a crucial role in the occurrence of hydrogen spillover. These results unambiguously identify the occurrence of hydrogen spillover from the metal surface to the noble metal/metal oxide interface and the resultant enhanced catalytic activity of the metal/oxide interface in low‐temperature CO oxidation, which provides a molecular‐level understanding of both H₂‐promoted catalytic activity of metal/oxide ensembles in low‐temperature CO oxidation and hydrogen spillover.     

Eco-friendly solution processing of all-polymer solar cells: Recent advances and future perspective

All-polymer solar cells (all-PSCs) exhibit great potentials in commercial applications. All-PSCs have observed steady performance gains with power conversion efficiency now reaching over 17% in the open literature. However, the current processing of all-PSCs relies predominantly on toxic, chlorinated solvents in moisture-free environments, representing a significant barrier for their commercialization due to the added costs to handle and dispose of such solvents. There is thus an urgent need for safe, environmentally benign, and sustainable ink-based processing methods to produce all-PSC devices reliably and reproducibly in ambient air. In this perspective, fundamental insights on the interplay between all-polymer blend morphologies and eco-friendly solvents are provided. Also, we discuss the recent successes of the green processing methods to manipulate the photoactive morphologies for high-efficiency all-PSCs. In the end, we provide an outlook on future challenges and opportunities of eco-friendly solvents processed all-PSCs for large-scale manufacturing.     

Gorenstein projective bimodules via monomorphism categories and filtration categories

We generalize the monomorphism category from quiver (with monomial relations) to arbitrary finite dimensional algebras by a homological definition. Given two finite dimension algebras A and B, we use the special monomorphism category $\mathsf{Mon}(B,A\text{-}\mathsf{Gproj})$ to describe some Gorenstein projective bimodules over the tensor product of A and B. If one of the two algebras is Gorenstein, we give a sufficient and necessary condition for $\mathsf{Mon}(B,A\text{-}\mathsf{Gproj})$ being the category of all Gorenstein projective bimodules. In addition, if both A and B are Gorenstein, we can describe the category of all Gorenstein projective bimodules via filtration categories. Similarly, in this case, we get the same result for infinitely generated Gorenstein projective bimodules.     

Triple Frustrated Lewis Pair-Type Reactivity on a Single Rare-Earth Metal Center

Rare-earth metal cations have been used rarely as Lewis-acidic components in the chemistry of frustrated Lewis pairs (FLPs). Herein, we report the first cerium/phosphorus system ( 2 ) employing a heptadentate N₄P₃ ligand, which exhibits triple FLP-type reactivity towards a series of organic substrates, including isocyanates, isothiocyanates, diazomethane, and azides on a single rare-earth Lewis acidic Ce center. This result shows that the Ce center and three P atoms in 2 could simultaneously activate three equivalents of small molecules under mild conditions. This study broadens the diversity of FLPs and demonstrates that rare earth based FLP exhibit unique properties compared with other FLP systems.     

Simultaneous determination of paeoniflorin from total glucosides of paeony in Sprague–Dawley rats and spontaneously hypertensive rats by high‐performance liquid chromatography–tandem mass spectrometry: in vivo and in vitro studies

Paeoniflorin is a well‐known monoterpene glucoside in the herbal drug that exhibits a number of biological activities. The pharmacokinetic characteristics of paeoniflorin from total glucosides of paeony in spontaneously hypertensive rats (SHR) are still unclear. It is essential to investigate the in vivo and in vitro pharmacokinetic differences of paeoniflorin from total glucosides of paeony in Sprague–Dawley (SD) and SHR. The in vivo pharmacokinetic data were analyzed using DAS 2.0 software and the in vitro metabolic characteristics were measured using rat hepatic microsomes. The concentration of paeoniflorin in biological samples was determined using high‐performance liquid chromatography–electrospray ionization tandem mass spectrometry method, which showed good precision and stability. The plasma concentration–time profiles of paeoniflorin following oral administration of total glucosides of paeony showed a single peak and there were significant differences in the mean values of AUC_(0–t), AUC_(0–∞), CL_z/F and T_max between SD and SHR (p < 0.05). The metabolic rate of paeoniflorin from total glucosides of paeony was slower in SHR than in SD rats (p < 0.05). The results might be useful in further applications of paeoniflorin and total glucosides of paeony. Copyright © 2016 John Wiley & Sons, Ltd.