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31.
It is shown that, contrary to common belief, monochromatic light beams are, in general, not spatially completely coherent, i.e., they will, in general, not produce fringes of unit visibility in a Young's double pinhole interference experiment. We cite experiments with laser modes which confirm this result. 相似文献
32.
Abstract The synthesis and characterization of new vinyl chloride-p-acryloyloxyazobenzene copolymers are reported. Kinetics of photoinduced trans-cis and thermal cis-trans isomerization of azo pendant groups in copolymer have also been investigated, and the kinetic parameters were evaluated. An azo acrylate model compound was used for comparison. 相似文献
33.
Emil Tashev Tania Tosheva Stoycho Shenkov Anne-Sophie Chauvin Victoria Lachkova Rosica Petrova 《Supramolecular chemistry》2013,25(7):447-457
The synthesis and characterization of several new phosphorus-containing partially lower rim substituted derivatives of 5,11,17,23-tetra(t-butyl) calix(4)arene (I) and 5,11,17,23-tetra(t-octyl)calix(4)arene (II), namely 5,11,17,23-tetra(t-butyl)-25,27-dihydroxy-26,28-bis(diphenylphosphinoyl-oxy) calix(4)arene (IV); 5,11,17,23-tetra(t-butyl)-25-hydroxy-26,27,28-tris(tetramethyldiamido-phosphinoyl-oxy) calix(4)arene (Vb); 5,11,17,23-tetra(t-butyl)-25,27-dihydroxy-26,28-bis(dimethyl-phosphinoyl-methoxy) calix(4)arene (VI); 5,11,17,23-tetra (t-octyl)-25,27-dihydroxy-26,28-bis(dimethyl-phosphinoyl-methoxy) calix(4)arene (VII) are reported. The structure of the synthesized calix(4)arene derivatives are identified and confirmed by elemental analysis, IR, 1H, 13C, 31P{1H} NMR spectroscopy and mass spectrometry as and X-ray crystallographic analysis of 5,11,17,23-tetra(t-butyl)-25,27-dihydroxy-26,28-bis(dimethyl-phosphinoyl-methoxy) calix(4)arene VI. According to the NMR spectra, all calix(4)arenes are in cone conformation. 相似文献
34.
Chuan Li Marharyta Petukh Lin Li Emil Alexov 《Journal of computational chemistry》2013,34(22):1949-1960
Due to the enormous importance of electrostatics in molecular biology, calculating the electrostatic potential and corresponding energies has become a standard computational approach for the study of biomolecules and nano‐objects immersed in water and salt phase or other media. However, the electrostatics of large macromolecules and macromolecular complexes, including nano‐objects, may not be obtainable via explicit methods and even the standard continuum electrostatics methods may not be applicable due to high computational time and memory requirements. Here, we report further development of the parallelization scheme reported in our previous work (Li, et al., J. Comput. Chem. 2012, 33, 1960) to include parallelization of the molecular surface and energy calculations components of the algorithm. The parallelization scheme utilizes different approaches such as space domain parallelization, algorithmic parallelization, multithreading, and task scheduling, depending on the quantity being calculated. This allows for efficient use of the computing resources of the corresponding computer cluster. The parallelization scheme is implemented in the popular software DelPhi and results in speedup of several folds. As a demonstration of the efficiency and capability of this methodology, the electrostatic potential, and electric field distributions are calculated for the bovine mitochondrial supercomplex illustrating their complex topology, which cannot be obtained by modeling the supercomplex components alone. © 2013 Wiley Periodicals, Inc. 相似文献
35.
Ilya Kuselman Elena Kardash Emil Bashkansky Francesca Pennecchi Stephen L. R. Ellison Karen Ginsbury Malka Epstein Aleš Fajgelj Yury Karpov 《Accreditation and quality assurance》2013,18(6):459-467
A new technique for quantification of human errors in chemical analysis using expert judgments is described. This technique is based on the house-of-security approach developed recently in the field of safety and security for prevention of terrorist and criminal attacks against an organization. The following relative quantification parameters (expressed in %) are proposed in the technique: (a) likelihood score of human error in a chemical analytical measurement/testing method, (b) severity score of human error for reliability of the test results, (c) importance score of a component of a laboratory quality system, and (d) effectiveness score of the quality system as a whole in preventing/blocking human error. As an example, 34 scenarios of human error in pH measurement of groundwater are discussed and quantified. 相似文献
36.
Emil I. Muresan Mioara Drobota Alexandra Bargan Corina A. M. Dumitriu 《Central European Journal of Chemistry》2014,12(4):528-536
This paper reports a systematic study on the preparation, characterization and testing of metallosilicate macrobeads that contain chromium ions as active catalytic centers. In order to obtain hard macrospheres, four metals (Cr, Al, Zr and Zn) were incorporated into the silica matrix using chitosan as a template and shape generator. Metallosilicate macrospheres were synthesized at room temperature using tetraethylorthosilicate as silicon source and chlorohydric acid as catalyst. The size of metallosilicate macrospheres was in the range 0.9 — 1.1 mm. The catalyst was characterised by means of water sorption technique, FTIR spectroscopy and SEM/EDX analyses. FTIR spectra put into evidence the presence of metallic ions within the silica framework. EDX analyses confirmed the efficient incorporation of metals within the silica matrix (the content of metals from the calcined catalyst is almost the same as that from the initial gel mixture). Porous structure of catalyst investigated by water sorption technique and by pycnometric methods (with n-heptan and mercury respectively) proved that the synthesized catalyst had micro, meso and macropores. Catalyst was tested in the esterification reaction of acetic acid with epichlorohydrin. The temperature and the amount of catalyst exerted a marked influence on reaction rate. This work opens new perspectives for heterogeneous catalysis encouraging the replacement of powder catalysts with macrospherical catalysts that are easy to recover and to reuse. 相似文献
37.
Laura E. Muresan Adrian I. Cadis Ioana Perhaita Emil Indrea 《Central European Journal of Chemistry》2014,12(10):1023-1031
Yttrium silicate doped with cerium (Y2SiO5:Ce) was obtained from Y-Ce-Si based precursors prepared by the simultaneous addition of reagents (SimAdd) technique. The synthesis of the precursors was done in well controlled conditions using ammonium oxalate, ammonium carbonate or urea as precipitating agents. Results regarding the influence of precipitating agents on the morpho structural and photoluminescent characteristics of Y2SiO5:Ce are reported. The TG analysis in correlation with EGA, FT-IR and XRD investigations reveals the formation of oxalate, hydroxy-carbonate or hydroxy-nitrate based compounds, the same as the conversion of the precursors to well crystallized yttrium silicate. XRD patterns show that the precursors are amorphous except for the sample prepared with ammonium oxalate. Depending on the precipitation conditions, the phosphors phase composition varies from single phase (X2-Y2SiO5) to a mixture of phases (X2-Y2SiO5, X1-Y2SiO5, Y2O3). Under UV excitation, phosphors exhibit the specific blue emission of cerium with an intensity that varies from 175.8% (urea) to 96.0% (ammonium carbonate) and to 78.5% (ammonium oxalate). The emission intensity depends on the phase purity and order degree of the phosphors. PACS Classification codes:78.55 Hx, 81.20Fw 相似文献
38.
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40.
Michael Hengge Paul Hänsch Daniel Ehjeij Frank S. Benneckendorf Jan Freudenberg Uwe H. F. Bunz Klaus Müllen Emil J. W. List-Kratochvil Felix Hermerschmidt 《Journal of polymer science. Part A, Polymer chemistry》2022,60(12):1878-1886
An increasing number of organic light-emitting diodes (OLEDs) is nowadays based on the use of polymers as the emissive material. For this material class in particular, solution-processing of the OLEDs has gained traction in both research and industry. However, in order to access multilayer material systems, orthogonal solvents must be used to prevent dissolution of previously prepared layers. The use of crosslinkers can facilitate this production method by reducing the number of orthogonal solvents needed since insoluble networks are generated. In this work, a novel bisazide crosslinker is employed to insolubilize Super Yellow, a polyphenylene-vinylene emitter. This allows the use of an additional poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine electron blocking layer (EBL) from the same solvent. Devices including the blocking layer show improved efficacies compared to reference devices without the additional EBL, while also maintaining the emission spectrum. Using the upscalable technique of doctor blading, OLEDs were fabricated which showed a particularly noticeable effect of the blocking layer with a nearly twofold increase in luminance and a 56% increase in current efficacy. 相似文献