Trinary arithmetic and logic unit (TALU) using savart plate and spatial light modulator (SLM) suitable for optical computation in multivalued logic

Arithmetic logic unit (ALU) is the most important unit in any computing system. Optical computing is becoming popular day-by-day because of its ultrahigh processing speed and huge data handling capability. Obviously for the fast processing we need the optical TALU compatible with the multivalued logic. In this regard we are communicating the trinary arithmetic and logic unit (TALU) in modified trinary number (MTN) system, which is suitable for the optical computation and other applications in multivalued logic system. Here the savart plate and spatial light modulator (SLM) based optoelectronic circuits have been used to exploit the optical tree architecture (OTA) in optical interconnection network.     

Amyloid‐Like Fibrillogenesis through Supramolecular Helix‐Mediated Self‐Assembly of Tetrapeptides Containing Non‐Coded α‐Aminoisobutyric Acid (Aib) and 3‐Aminobenzoic Acid (m‐ABA)

Single‐crystal X‐ray diffraction studies of two terminally protected tetrapeptides Boc‐Ile‐Aib‐Val‐m‐ABA‐OMe ( I ) and Boc‐Ile‐Aib‐Phe‐m‐ABA‐OMe ( II ) (Aib=α‐aminoisobutyric acid; m‐ABA=meta‐aminobenzoic acid) reveal that they form continuous H‐bonded helices through the association of double‐bend (type III and I) building blocks. NMR Studies support the existence of the double‐bend (type III and I) structures of the peptides in solution also. Field emission scanning electron‐microscopic (FE‐SEM) and high‐resolution transmission electron‐microscopic (HR‐TEM) images of the peptides exhibit amyloid‐like fibrils in the solid state. The Congo red‐stained fibrils of peptide I and II , observed between crossed polarizers, show green‐gold birefringence, a characteristic of amyloid fibrils.     

An efficient synthesis of (7S,10R)-2-bromo-5,6,7,8,9,10-hexahydro-7,10-epiminocyclohepta[b]indole: application in the preparation and structural confirmation of a potent 5-HT6 antagonist

(7S,10R)-5-Methyl-2-((3-(trifluoromethyl)phenyl)sulfonyl)-5,6,7,8,9,10-hexahydro-7,10-epiminocyclohepta[b]indole 1a is a potent 5-HT₆ antagonist (h5-HT₆ K_i = 1.5 nM) which is derived from an epiminocyclohept[b]indole scaffold. In order to synthesize 1a on a multi-gram scale to support advanced biological testing, an efficient chiral resolution of the intermediate tert-butyl 2-bromo-5,6,7,8,9,10-hexahydro-7,10-epiminocyclohepta[b]indole-11-carboxylate 2 was developed. After derivatizing 2 with (1R)-(?)-menthyl chloroformate it was found that a single diastereomer 7a could be isolated by selective precipitation from n-hexane. The absolute stereochemistry of 7a was determined by X-ray crystallography and the structure was confirmed as (7S,10R)-tert-butyl 2-bromo-5,6,7,8,9,10-hexahydro-7,10-epiminocyclohepta[b]indole-11-carboxylate. Removal of the chiral auxiliary under basic conditions afforded intermediate 2a in >99% enantiomeric purity and with 80% yield based on recovery from the racemic compound 2. Intermediate 2a was used successfully to synthesize 5-HT₆ antagonist 1a on a multi-gram scale.     

Synthesis and Raman signature for the formation of CdO/MnO2 (core/shell) nanostructures

In the present report, bare CdO and CdO/MnO₂ core/shell nanostructures of various cores and different shell sizes were synthesized using co‐precipitation method. The phase, size, shape and structural details of the bare CdO and CdO/MnO₂ nanostructures were investigated by X‐ray diffraction, transmission electron microscopy (TEM), and Raman spectroscopy measurements. TEM micrographs confirm the formation of core/shell nanostructures. The presence of CdO (core) and MnO₂ (shell) crystal phases was determined by analyzing the Raman data of bare CdO and CdO/MnO₂ core/shell nanostructures. The Raman spectra of bare CdO nanostructures contain one broad intense convoluted envelop of three bands in the spectral range of 200–500 cm⁻¹ and a weaker band located at ~940 cm⁻¹. The intensity of these two Raman bands is decreased with the increase of shell size and disappeared completely for the shell size 5.3 ± 1 nm. Further, two new Raman bands appeared at ~451 and ~665 cm⁻¹ for the shell size 1.3 ± 0.1 nm. These two Raman bands are assigned to the deformation of Mn–O–Mn and Mn–O stretching modes of MnO₂. The intensity of these two Raman bands is enhanced with the increase of shell size and attains a maximum value for the shell size 5.3 ± 1 nm. The disappearance of characteristics Raman bands of CdO phase and the appearance of characteristics Raman bands corresponding to MnO₂ phase for nanostructures of shell size 5.3 ± 1 nm authenticate the presence of CdO as core and MnO₂ as shell in the core/shell nanostructures. Copyright © 2014 John Wiley & Sons, Ltd.     

Eu activated M6AlP5O20 (M=Sr/Ba/Mg) novel red phosphors

Eu³⁺ activated M₆AlP₅O₂₀ (where M=Sr/Ba/Mg) phosphors prepared by combustion synthesis and the completion of the synthesis was confirm by XRD (X-ray diffraction) patterns. The surface morphology studied by scanning electron microscopy (SEM) and photoluminescence (PL) properties has been reported in this paper. The Eu³⁺ PL emission spectrum was observed in M₆AlP₅O₂₀ phosphors (where M=Sr/Ba/Mg) at 592 (orange) and 618 nm (red) region, the spectrum due to ⁵D₀→⁷F₁ and ⁵D₀→⁷F₂ transitions at mercury free excitation, respectively. Its considerable emission intensity under 350 nm excitations makes it possible candidate materials as red component of tricolor luminescence materials and for near ultra violet light emitting diode (n-UVLED) phosphors.     

Real-world quantum sensors: evaluating resources for precision measurement

Quantum phenomena present in many experiments signify nonclassical behavior, but do not always imply superior performance. Quantifying the enhancement achieved from quantum behavior needs careful analysis of the resources involved. We analyze the case of parameter estimation using an optical interferometer, where increased precision can in principle be achieved using quantum probe states. Common performance measures are examined and some are shown to overestimate the improvement. For the simplest experimental case we compare the different measures and exhibit this overestimation explicitly. We give the preferred analysis of these experiments and calculate benchmark values for experimental parameters necessary to realize a precision enhancement. Our analysis shows that unambiguous real-world enhancements in optical quantum metrology with fixed photon number are yet to be attained.     

Size dependent electron-phonon coupling in Li0.5Co0.1Fe2.4O4 nanoparticles investigated by Raman spectroscopy

The Raman spectra of Li_0.5Co_0.1Fe_2.4O₄ nanoparticles have been recorded in the spectral range, 400-800 cm⁻¹ at four different particle sizes. X-ray and TEM measurements were done to determine crystal structure and size of the nanoparticles. X-ray diffraction (XRD) shows that the Li_0.5Co_0.1Fe_2.4O₄ nanoparticles have an order phase spinel structure without any impurity. The size of the nanocrystal was calculated through XRD patterns and TEM micrographs and it turns out to be 34-42 nm. The Raman spectra of each size nanoparticles show five Raman bands. The most intense Raman band shows a noticeable asymmetrical feature towards lower wavenumber side. A line shape analysis was performed to get the exact spectral parameters of the Raman bands. The intensity of asymmetrical feature keeps on increasing with decreasing the particle size from 42 nm to 34 nm and finally evolved as a new Raman band. The appearance of new band and its intensity response relative to the intensity of the main Raman band as a function of particle size has been explained in terms of electron-phonon coupling. It was observed that the strength of electron-phonon coupling goes on increasing with reducing the particle size. The red shifting of the Raman bands upon reducing the crystalline size is explained in terms of the lattice expansion, which is well supported by the XRD data.