Suppression of surface pattern formation in spin‐coated polymer films by the addition of polydimethylsiloxane‐grafted silica nanoparticles

Polydimethylsiloxane (PDMS)‐grafted nanoparticles and PDMS were added, respectively, to inhibit the dewetting of polymer films and the formation of surface patterns in spin coating. Uniform and flat films were successfully achieved with the addition of PDMS‐grafted silica nanoparticles or PDMS. Time‐of‐flight secondary ion mass spectrometry depth profiling indicated that PDMS‐grafted silica nanoparticles and PDMS preferentially segregated to the surface. A high concentration of bromine end groups was observed at the interface. The surface layer of PDMS or PDMS‐grafted silica nanoparticles can decrease the surface tension of the polymer solutions and reduce the evaporation rates of the solvents, providing more time for the bromine end groups to anchor themselves at the silicon substrates. Copyright © 2016 John Wiley & Sons, Ltd.     

Influence of Poly (methyl metacrylate) Addition on Resistive Switching Performance of P3HT/P(VDF-TrFE) Blend Films

Organic semiconducting/ferroelectric blend films attracted much attention due to their elec-trical bistability and rectification properties and thereof the potential in resistive memory devices. Blend films were usually deposited from solution, during which phase separation oc-curred, resulting in discrete semiconducting phase whose electrical property was modulated by surrounding ferroelectric phase. However, phase separation resulted in rough surface and thus large leakage current. To further improve electrical properties of such blend films, poly(methyl metacrylate) (PMMA) was introduced as additive into P3HT/P(VDF-TrFE) semiconducting/ferroelectric blend films in this work. It indicated that small amount of PMMA addition could effectively enhance the electrical stability to both large electrical stress and electrical fatigue and further improve retention performance. Overmuch PMMA addition tended to result in the loss of resistive switching property. A model on the con-figuration of three components was also put forward to well understand our experimental observations.     

Synergistic copper-TEMPO catalysis of intermolecular vicinal diamination of styrenes

A copper-catalyzed, 2,2,6,6-tetramethyl piperidine N-oxy radical-assisted intermolecular diamination of styrenes with N-fluorobenzenesulfonimide has been developed. The current protocol proved amenable to a diverse array of styrenes via cascade radical addition to readily afford synthetically useful aromatic vicinal diamines with exclusive diastereoselectivity.     

Effects of temperature and current density on the porous structure of InP

Journal of Solid State Electrochemistry - The electrochemical oscillations that occur during the etching of InP and the three-dimensional (3D) porous structure of the resulting material were...     

All-optical phase and amplitude regeneration of return-to-zero differential phase shift keying data

We report a novel implementation of an all-optical rephasing, reshaping, and reamplification differential phase shift keying (DPSK) regenerator. The rephasing is based on converting phase noise into amplitude noise by using an interferometric configuration and then eliminating the amplitude noise by using a semiconductor optical amplifier (SOA). The reshaping is performed using gain competition and gain compression in a saturated SOA. The scheme was tested using 10Gbit/s, 2(23)-1 pseudorandom bit sequence return-to-zero DPSK data. The measurement shows removal of the degraded data error floor with a 6 order-of-magnitude improvement in bit-error rate. The measured negative power penalty is about 4dB. Mathematical analysis shows a reduction in DPSK phase-noise power by half.     

Maturation-dependent microstructure length scale in the corpus callosum of fixed rat brains by magnetic resonance diffusion-diffraction

Techniques capable of assessing microstructure length scale are potentially useful in probing the integrity of biologic tissue at the microscopic level. Although the magnetic resonance (MR) diffusion-diffraction technique has been proposed for years, its realization in an undissected brain has not been reported on. In this study, validation of this method in a phantom simulating a series of repeated sheets of water with regular spacing was first performed. The same technique was applied to the corpus callosum of fixed rat brains of different ages (range, 21-84 days). The phantom was constructed with a pile of transparencies immersed in water doped with Gd-DTPA. The measured signal showed diffraction-like coherence peaks, the modulation of which was influenced by the gap distance and the center-to-center distance of the adjacent gaps. The measured distances were consistent with the actual values. In five 84-day-old rats, the diffusion length scale derived from the diffractogram was highly reproducible. In the course of brain maturation, the measured size decreased with age. Electron microscopy showed that axons on day 21 were smaller in diameter and less myelinated as compared with those on day 84. Progressive decrease in the diffusion length scale observed during brain maturation might reflect a gradual decrease in transmembrane permeability due to myelination. In conclusion, MR diffusion-diffraction can be observed in the corpus callosum of fixed rat brains. This technique might be useful in probing the status of myelination in the development of disease.     

Synthesis and structural characterization of lanthanide complexes with the di- or tri-anionic diguanidinate ligand: new insight into the flexibility and distinct reactivity of the linked diguanidinate ligand

Unprecedented disproportionation and deprotonation of the linked diguanidinate ligand have been established, demonstrating, for the first time, that the number and distribution of negative charges on the diguanidinate ligand are tunable, and representing a new and efficient method for synthesis of linked diguanidinate di- and tri-anion complexes.     

Cationic corrole derivatives: a new family of G-quadruplex inducing and stabilizing ligands

Water-soluble cationic corrole derivatives were designed and synthesized, and the first observation of their interactions with the telomeric G-quadruplex was made.     

High‐temperature oxidation behavior of Ni‐based superalloys with Nb and Y and the interface characteristics of oxidation scales

Ni‐based superalloys with niobium (Nb) or/and yttrium (Y) were prepared by vacuum melting. The oxidation kinetics of these alloys was studied by thermogravimetry at 800 °C for 100 h in static air. Morphology of oxides was studied using SEM, and the composition was analyzed by X‐ray diffraction. Energy‐dispersive X‐ray spectrometer was employed to examine the linear element distribution of the cross section of the oxidation films. Results showed that the oxidation kinetics all followed a parabolic law at different stages. The oxide films were mainly comprised of Cr₂O₃, NiCr₂O₄, Al₂O₃ and TiO₂. All the oxide films exhibited layered structure owing to different oxidation stages. With the addition of Nb or Y, the high‐temperature oxidation resistance of the superalloy was improved significantly and the surface morphology of the oxidation film was ameliorated. The comprehensive effect of Nb and Y was remarkable in improving the high‐temperature oxidation resistance of Ni‐based alloys. Copyright © 2014 John Wiley & Sons, Ltd.     

An Efficient Synthesis of Chromeno[2,3‐d]pyrimidine‐2,4‐diones with a Nitroketene‐Aminal Moiety at C(5) by a One‐Pot Four‐Component Reaction

An efficient and novel synthesis of chromeno[2,3‐d]pyrimidine‐2,4‐dione derivatives with a nitroketene‐aminal moiety at C(5) via four‐component reaction of salicylaldehydes, barbituric acid, diamines, and 1,1‐bis(methylsulfanyl)‐2‐nitroethene in EtOH and in the presence of AcOH is reported. Easy performance, good yields, and easy purification are the main advantages of this method. All structures were confirmed by IR, MS, and ¹H‐ and ¹³C‐NMR, and by X‐ray crystal‐structure analyses. A plausible mechanism for this type of reaction is proposed (Scheme).