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The morphology dependent optical properties of Tb3+ in YbPO4 host lattice have been investigated. 10 % Terbium doped ytterbium phosphate (YbPO4:Tb3+) nanostructures (NSs) were synthesized by five different synthetic methods i.e. s...
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The morphology dependent optical properties of Tb3+ in YbPO4 host lattice have been investigated. 10 % Terbium doped ytterbium phosphate (YbPO4:Tb3+) nanostructures (NSs) were synthesized by five different synthetic methods i.e. sonochemical method, hydrothermal method, solvothermal method, sacrificial template method and coprecipitation method. Structural facets and optical properties of fabricated nanoparticles were studied in detail by powder X-ray diffraction (PXRD), Fourier transform infrared spectrum (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectra (EDS), and photoluminescence (PL) techniques. We have investigated the impact of synthetic procedures employed on the morphology and uniformity of synthesized NSs and consequently on the optical properties of the NSs. The intense green emission from the nanophosphor shows that phosphor can be used in IR-sensors, LEDs and as solar spectrum converters.
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Thiophenes are a highly important group of heterocycles and have been of great interest to researchers due to their various reactivities. Many synthetic strategies are used to generate functionalized thiophene derivatives. Several...
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Thiophenes are a highly important group of heterocycles and have been of great interest to researchers due to their various reactivities. Many synthetic strategies are used to generate functionalized thiophene derivatives. Several reactions are described, depending on the reactivity of the substituents attached to the thiophene nucleus toward different nucleophiles to yield the versatile thiophene products. Many diverse applications have been utilized for thiophenes from medicinal chemistry to material science.
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This paper is a report on current efforts at the Department of Speech, Music and Hearing, KTH, on data-driven multimodal synthesis including both visual speech synthesis and acoustic modeling. In the research we try to combine bot...
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This paper is a report on current efforts at the Department of Speech, Music and Hearing, KTH, on data-driven multimodal synthesis including both visual speech synthesis and acoustic modeling. In the research we try to combine both corpus based methods with knowledge based models and to explore the best of the two approaches. In the paper an attempt to build formant-synthesis systems based on both rule-generated and database driven methods is presented. A pilot experiment is also reported showing that this approach can be a very interesting path to explore further. Two studies on visual speech synthesis are reported, one on data acquisition using a combination of motion capture techniques and one concerned with coarticulation, comparing different models. (C) 2005 Elsevier B.V. All rights reserved.
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Background: Silver nanoparticles (AgNPs), are amongst the utmost striking nanosizedmaterials that are extensively applied in a variety of biomedical applications whichincludes diagnostic use, disease management, medical device coa...
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Background: Silver nanoparticles (AgNPs), are amongst the utmost striking nanosizedmaterials that are extensively applied in a variety of biomedical applications whichincludes diagnostic use, disease management, medical device coating, drug delivery and forpersonal health care.Discussion: With the growing interest and its application in the health care sector, it is becomingnecessary for a better understanding and exploration of AgNPs mechanism of actionlike biological interaction, their possible toxicity, and safety concern to human exposure.AgNPs have been the subject of researchers attention and interest due to the uniqueproperties and quality such as shape and size depending optical, electrical, and antimicrobialpotentials (antibacterial, antifungal, antiviral etc.). In recent times, several studies havebeen conducted on AgNPs antimicrobial potential and also a number of patents related to itssynthesis, clinical role and importance have also been registered. In this review, a shortoverview of AgNPs synthesis approach is presented (physical, chemical, and biological orgreen synthesis) and it also delivers a historical outlook of AgNPs application as an antimicrobialagent which includes combined evidence of microbial resistance and safety issueswith human exposure.
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The core structure of the complex pentacyclic 5,11-methanomorphanthridine skeleton and the vicinal quaternary and tertiary stereocenters of the 5,10b-phenanthridine skeleton are constructed stereospecifically in one step employing...
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The core structure of the complex pentacyclic 5,11-methanomorphanthridine skeleton and the vicinal quaternary and tertiary stereocenters of the 5,10b-phenanthridine skeleton are constructed stereospecifically in one step employing intramolecular 1,3-dipolar cyclo - addition of a nonstabilized azomethine ylide (AMY) generated by the sequential double desilylation of appropriate bis-trimethylsilylmethyl amines using Ag(I)F as a single-electron oxidant. The strategy is successfully applied for the total synthesis of biologically active alkaloids such as (±)-pancracine, (±)-brunsvigine, (±)-maritidine, and (±)-crinine.
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Syntheses of racemic pterocarpin, its thia- and aza-pterocarpin have been achieved in a modular manner using sesamol iodide, diethyl malonate and 3-methoxyphenol, 3-methoxythiophenol and N-tosyl-3-methoxyaniline as building blocks...
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Syntheses of racemic pterocarpin, its thia- and aza-pterocarpin have been achieved in a modular manner using sesamol iodide, diethyl malonate and 3-methoxyphenol, 3-methoxythiophenol and N-tosyl-3-methoxyaniline as building blocks. Copper-mediated Hurtley coupling, Mitsunobu reaction, IBX-mediated oxidation, Pinnick oxidation, and intramolecular Friedel-Crafts acylation have been successfully exploited in the synthesis.
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The development of a two-step synthesis of multisubstituted N-methoxyamines from N-methoxyamides is reported. Utilization of the N-methoxy group as a reactivity control element was the key to success in this two-step synthesis. Th...
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The development of a two-step synthesis of multisubstituted N-methoxyamines from N-methoxyamides is reported. Utilization of the N-methoxy group as a reactivity control element was the key to success in this two-step synthesis. The first reaction involves a N-methoxyamide/aldehyde coupling reaction. Whereas ordinary amides cannot condense with aldehydes intermolecularly due to the poor nucleophilicity of the amide nitrogen, the N-methoxy group enhances the nucleophilicity of the nitrogen, enabling the direct coupling reaction. The second reaction in the twostep process was nucleophilic addition to the N-methoxyamides. Incorporation of the N-methoxy group into the amides increased the electrophilicity of the amide carbonyls and promoted the chelation effect. This nucleophilic addition enabled quick diversification of the products derived from the first step. The developed strategy was applicable to a variety of substrates, resulting in the elaboration of multi-substituted piperidines and acyclic amines, as well as a substructure of a complex natural alkaloid.
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The synthesis and the first X-ray structural characterization of a selenenyl selenocyanate, [o-(2,6-diisopropylphenyliminomethinyl) phenyl]selenenyl selenocyanate (DiPhSeSeCN), with a stable Se-Se bond are described. The isolation...
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The synthesis and the first X-ray structural characterization of a selenenyl selenocyanate, [o-(2,6-diisopropylphenyliminomethinyl) phenyl]selenenyl selenocyanate (DiPhSeSeCN), with a stable Se-Se bond are described. The isolation of stable DiPhSeSeCN, both in the solid state and in solution, is facilitated by strong intramolecular Se?N interaction. The compound DiPhSeSeCN, an example of unsymmetrical diselenide, did not exhibit any glutathione peroxidase-like activity. The reaction of DiPhSeSeCN with thiophenol afforded (3H-benzo[c][1,2]diselenol-3-yl)(phenyl)sulfane.
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Stable and unstable mirror-lens cavities are studied. Relations are obtained for calculating the parameters of a laser beam formed by such cavities with planar and (or) spherical mirrors and one or two lenses. The expressions have...
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Stable and unstable mirror-lens cavities are studied. Relations are obtained for calculating the parameters of a laser beam formed by such cavities with planar and (or) spherical mirrors and one or two lenses. The expressions have no singularities and make it possible to simplify the operations substantially and automate the solution of problems of analysis and synthesis of stable and unstable mirror-lens cavities.
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Water has long been used and regarded as a solvent in the synthesis of noble-metal colloids, but its role remains largely unexplored in terms of reactivity and functionality. We demonstrate that water can serve as a reducing agent...
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Water has long been used and regarded as a solvent in the synthesis of noble-metal colloids, but its role remains largely unexplored in terms of reactivity and functionality. We demonstrate that water can serve as a reducing agent for the synthesis of platinum (Pt) nanocrystals. Starting with only two components, i.e., K_2PtCl_4 and deionized water, we successfully synthesized Pt nanocrystals with an average size of 1.9 nm, without the aid of any exotic reducing agents as well as organic capping agents or stabilizers. Because of small particle sizes, these Pt nanocrystals exhibited a high activity toward the oxygen reduction reaction.
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