Search results for "electronics"
showing 10 items of 4340 documents
ChemInform Abstract: Microwave-Assisted Tandem Organocatalytic Peptide-Coupling Intramolecular aza-Michael Reaction: α,β-Unsaturated N-Acyl Pyrazoles…
2015
Conjugated N-acyl pyrazoles are successfully employed in the organocatalytic enantioselective intramolecular aza-Michael reaction as ester surrogates.
Theoretical characterization of the electronic structure of polymeric systems combining disilanylene and /spl pi/-conjugated units
1994
Summary form only given. Polymeric organosilicon systems are in the forefront of research, due to their intriguing properties (semiconducting behavior, photoconduction, non-linear optical properties, and thermo- and piezochromism). The fundamental skeletons of most of these polymers consist of a /spl sigma/-electron network formed by silicon-silicon bonds. Recently, polymeric organosilicon systems containing a regular alternation of a disilanylene unit and carbon /spl pi/-conjugated moiety as phenylene, ethynylene, or ethenylene have been synthesized. The purpose of this contribution is to perform a detailed study of the electronic structure of polymers containing alternated disilanylene an…
Precise structural investigation of symmetric diblock copolymer thin films with resonant soft X-ray reflectivity
2013
Symmetric diblock copolymers are known to form lamellar structures in the bulk of an organic thin film. Polymer/polymer and polymer/substrate interfaces play a critical role in this application. Here, we report the investigation of multiple buried interfaces by using a novel technique resonant soft X-ray reflectivity which benefits from enhanced contrast between different polymers near the carbon K-edge. This allows us to obtain a precise interface structure. We also present an alternative method to determine optical constants of polymers by fitting X-ray reflectivity of polymers with known structural parameters at specific soft X-ray energies. This approach is compared with the way of obta…
Non-linear optical spectra of excitons in polydiacetylene
1992
Abstract Adding long-range Coulomb interactions to the Su-Schrieffer-Heeger model makes it possible to investigate excitonic states in conjugated polymers. Various characteristic features due to these states as well as due to the electron-hole continuum can be found in the calculated non-linear optical susceptibilities. In particular the electroabsorption spectrum and the third harmonic generation intensity and its dependence on the system size are examined. Using only moderate interaction strength, various experiments in polydiacetylene can be interpreted in a consistent way.
<title>All-optical poling of DMABI molecules in a polymer matrix</title>
2005
Many organic compounds in solid state have nonlinear optical properties due to the orientation of the molecules in a polymer matrix. In this work, all-optical poling and second harmonic generation in a composition consisting of 1 mass% of N,N-dimethylaminobenzylidene 1,3-indandione (DMABI) compound in poly(methyl methacrylate) (PMMA) matrix were studied. Thin films were prepared by solvent casting. The 1.064-μm fundamental and 532-nm second harmonic wavelengths of a Nd:YAG laser were used. It is shown that DMABI molecules can be oriented by the method of all- optical poling, and that the process is related to the photoinduced switching between two equally stable states of the molecule.
Growth Mechanism and Surface Functionalization of Metal Chalcogenides Nanostructures
2014
Following the discovery of carbon fullerenes and nanotubes (NTs), nanostructured materials and their synthesis have attracted tremendous attention due to their superior mechanical properties, their unique electronic behavior, and their high potential in making technologically advanced nanodevices. Among different classes, layered metal chalcogenides nanostructures are of interest for a variety of applications ranging from nanoelectronics or as source materials for energy applications, nanotribology and in heterogeneous catalysis. These nanoparticles are metastable phases. Therefore, equilibrium methods are necessary to prevent the formation of the thermodynamically stable bulk phase. On the…
Electrical Behaviour of Heterobimetallic [MM′(EtCS2)4] (MM′=NiPd, NiPt, PdPt) and MM′X-Chain Polymers [PtM(EtCS2)4I] (M=Ni, Pd)
2012
Herein, we report the isolation of new heterobimetallic complexes [Ni0.6Pd1.4ACHTUNGTRENUNG(EtCS2)4] (1), [NiPtACHTUNGTRENUNG(EtCS2)4] (2) and [Pd0.4Pt1.6ACHTUNGTRENUNG(EtCS2)4] (3), which were constructed by using transmetallation procedures. Subsequent oxidation with iodine furnished the MM'X monodimensional chains [Ni0.6Pt1.4ACHTUNGTRENUNG(EtCS2)4I] (4) and [Ni0.1Pd0.3Pt1.6ACHTUNGTRENUNG(EtCS2)4I] (5). The physical properties of these systems were investigated and the chain structures 4 and 5 were found to be reminiscent of the parent [Pt2ACHTUNGTRENUNG(EtCS2)4I] species. However, they were more sensitively dependent on the localised nature of the charge on the Ni ion, which caused spont…
Investigation of Adsorption behaviour of Acetone Vapour towards a Surface Plasmon Resonance Sensing Layer using Adsorption Isotherm Models
2021
Abstract Surface plasmon resonance (SPR) sensors are widely explored due their ultra-sensitivity to even a minute alteration of refractive index. Knowledge of adsorption processes could be exploited to explain the performance and interaction mechanism of an SPR sensor. Here in, we report the fitting of the experimental SPR sensing data during the detection of low concentrations of acetone vapour (0.5-5 ppm) using the linearized and non-linearized format of the Langmuir and the Freundlich isotherm models. The sensing layer is made from a ternary composite material of doped polyaniline, reduced graphene oxide and chitosan. The objective is to find the best model, understand the interaction me…
Evidence for the formation of sodium hassate(VIII)
2004
SummaryHassium, element 108, was produced in the fusion reaction between26Mg and248Cm. The hassium recoils were oxidizedin-situto a highly volatile oxide, presumably HsO4, and were transported in a mixture of He and O2to a deposition and detection system. The latter consisted of 16 silicon PIN-photodiodes facing a layer of NaOH, which served, in the presence of a certain partial pressure of water in the transport gas, as reactive surface for the deposition of the volatile tetroxides. Six correlated α-decay chains of Hs were detected in the first 5 detectors centred around detection position 3. In analogy to OsO4, which forms Na2[OsO4(OH)2], an osmate(VIII), with aqueous NaOH, HsO4presumably…